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Sample records for charge electro osmotic

  1. Equilibrium Electro-osmotic Instability

    CERN Document Server

    Rubinstein, Isaak

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. First theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge-selectivity for the sake of simplicity and so did the subsequent numerical studies of various time-dependent and nonlinear features of electro-osmotic instability. In this letter, we show that relaxing the assumption of perfect charge-selectivity (tantamount to fixing the electrochemical potential in the solid) allows for equilibrium electro-osmotic instability. Moreover, we s...

  2. Equilibrium Electro-osmotic Instability

    OpenAIRE

    Rubinstein, Isaak; Zaltzman, Boris

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium elect...

  3. Topology and shape optimization of induced-charge electro-osmotic micropumps

    DEFF Research Database (Denmark)

    Gregersen, Misha Marie; Okkels, Fridolin; Bazant, M. Z.; Bruus, Henrik

    2009-01-01

    For a dielectric solid surrounded by an electrolyte and positioned inside an externally biased parallel-plate capacitor, we study numerically how the resulting induced-charge electro-osmotic (ICEO) flow depends on the topology and shape of the dielectric solid. In particular, we extend existing...... conventional electrokinetic models with an artificial design field to describe the transition from the liquid electrolyte to the solid dielectric. Using this design field, we have succeeded in applying the method of topology optimization to find system geometries with non-trivial topologies that maximize the...... design field. Our results show the importance of the topology and shape of the dielectric solid in ICEO systems and point to new designs of ICEO micropumps with significantly improved performance....

  4. A novel microfluidic valve controlledby induced charge electro-osmotic flow

    Science.gov (United States)

    Wang, Chengfa; Song, Yongxin; Pan, Xinxiang; Li, Dongqing

    2016-07-01

    In this paper, a novel microfluidic valve by utilizing induced charge electro-osmotic flow (ICEOF) is proposed and analyzed. The key part of the microfluidic valve is a Y-shaped microchannel. A small metal plate is placed at each corner of the junction of the Y-shaped microchannel. When a DC electrical field is applied through the channels, electro-osmotic flows occur in the channels, and two vortices will be formed near each of the metal plates due to the ICEOF. The two vortices behave like virtual ‘blocking columns’ to restrain and direct the flow in the Y-channel. In this paper, effects of the length of the metal plates, the applied voltages, the width of the microchannel, the zeta potential of the non-metal microchannel wall, and the orientation of the branch channels on the flow switching between two outlet channels are numerically investigated. The results show that the flow switching between the two outlet channels can be flexibly achieved by adjusting the applied DC voltages. The critical switching voltage (CSV), under which one outlet channel is closed, decreases with the increase in the metal plate length and the orientation angle of the outlet channels. The CSV, however, increases with the increase in the inlet voltage, the width of the microchannel, and the absolute value of the zeta potential of the non-metal microchannel wall. Compared with other types of micro-valves, the proposed micro-valve is simple in structure without any moving parts. Only a DC power source is needed for its actuation, thus it can operate automatically by controlling the applied voltages.

  5. Non-isothermal electro-osmotic flow in a microchannel with charge-modulated surfaces

    Science.gov (United States)

    Bautista, Oscar; Sanchez, Salvador; Mendez, Federico

    2015-11-01

    In this work, we present an theoretical analysis of a nonisothermal electro-osmotic flow of a Newtonian fluid over charge-modulated surfaces in a microchannel. Here, the heating in the microchannel is due to the Joule effect caused by the imposition of an external electric field. The study is conducted through the use of perturbation techniques and is validated by means of numerical simulations. We consider that both, viscosity and electrical conductivity of the fluid are temperature-dependent; therefore, in order to determine the heat transfer process and the corresponding effects on the flow field, the governing equations of continuity, momentum, energy and electric potential have to be solved in a coupled manner. The principal obtained results evidence that the flow patterns are perturbed in a noticeable manner in comparison with the isothernal case. Our results may be used for increasing microfluidics mixing by conjugating thermal effects with the use of charge-modulated surfaces. This work has been supported by the research grants no. 220900 of Consejo Nacional de Ciencia y Tecnología (CONACYT) and 20150919 of SIP-IPN at Mexico. F. Méndez acknowledges also the economical support of PAPIIT-UNAM under contract number IN112215.

  6. Electro-osmotic flows inside triangular microchannels

    International Nuclear Information System (INIS)

    This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.

  7. Maximum efficiency of the electro-osmotic pump

    Science.gov (United States)

    Xu, Zuli; Miao, Jianying; Wang, Ning; Wen, Weijia; Sheng, Ping

    2011-06-01

    Electro-osmotic effect in a porous medium arises from the electrically charged double layer at the fluid-solid interface, whereby an externally applied electric field can give rise to fluid flow. The electro-osmotic pump (EOP) is potentially useful for a variety of engineering and biorelated applications, but its generally low efficiency is a negative factor in this regard. A study to determine the optimal efficiency of the EOP and the condition(s) under which it can be realized is therefore of scientific interest and practical importance. We present the results of a theoretical and experimental study on the maximum efficiency optimization of the electrokinetic effect in artificially fabricated porous media with controlled pore diameters. It is shown that whereas the EOP efficiency increases with decreasing channel diameter, from 4.5 to 2.5 μm for samples fabricated on oxidized silicon wafers as expected for the interfacial nature of the electro-osmotic effect, the opposite trend was observed for samples with much smaller channel diameters fabricated on anodized aluminum oxide films, with the pore surface coated with silica. These results are in agreement with the theoretical prediction, based on the competition between interfacial area and the no-slip flow boundary condition, that an optimal efficiency of ˜1% is attained at a microchannel diameter that is five times the Debye length, with a zeta potential of ˜100 mV.

  8. Electro-osmotic flow enhancement in carbon nanotube membranes.

    Science.gov (United States)

    Mattia, Davide; Leese, Hannah; Calabrò, Francesco

    2016-02-13

    In this work, experimental evidence of the presence of electro-osmotic flow (EOF) in carbon nanotube membranes with diameters close to or in the region of electrical double layer overlap is presented for two different electrolytes for the first time. No EOF in this region should be present according to the simplified theoretical framework commonly used for EOF in micrometre-sized channels. The simplifying assumptions concern primarily the electrolyte charge density structure, based on the Poisson-Boltzmann (P-B) equation. Here, a numerical analysis of the solutions for the simplified case and for the nonlinear and the linearized P-B equations is compared with experimental data. Results show that the simplified solution produces a significant deviation from experimental data, whereas the linearized solution of the P-B equation can be adopted with little error compared with the full P-B case. This work opens the way to using electro-osmotic pumping in a wide range of applications, from membrane-based ultrafiltration and nanofiltration (as a more efficient alternative to mechanical pumping at the nanoscale) to further miniaturization of lab-on-a-chip devices at the nanoscale for in vivo implantation. PMID:26712647

  9. Ionic Origin of Electro-osmotic Flow Hysteresis

    Science.gov (United States)

    Lim, Chun Yee; Lim, An Eng; Lam, Yee Cheong

    2016-02-01

    Electro-osmotic flow, the driving of fluid at nano- or micro- scales with electric field, has found numerous applications, ranging from pumping to chemical and biomedical analyses in micro-devices. Electro-osmotic flow exhibits a puzzling hysteretic behavior when two fluids with different concentrations displace one another. The flow rate is faster when a higher concentration solution displaces a lower concentration one as compared to the flow in the reverse direction. Although electro-osmotic flow is a surface phenomenon, rather counter intuitively we demonstrate that electro-osmotic flow hysteresis originates from the accumulation or depletion of pH-governing minority ions in the bulk of the fluid, due to the imbalance of electric-field-induced ion flux. The pH and flow velocity are changed, depending on the flow direction. The understanding of electro-osmotic flow hysteresis is critical for accurate fluid flow control in microfluidic devices, and maintaining of constant pH in chemical and biological systems under an electric field.

  10. An analysis of electro-osmotic and magnetohydrodynamic heat pipes

    International Nuclear Information System (INIS)

    Mechanically simple methods of improving heat transport in heat pipes are investigated. These methods are electro-osmotic and magnetohydrodynamic augmentation. For the electro-osmotic case, a detailed electrokinetic model is used. The electrokinetic model used includes the effects of pore surface curvature and multiple ion diffusivities. The electrokinetic model is extended to approximate the effects of elevated temperature. When the electro-osmotic model is combined with a suitable heat-pipe model, it is found that the electro-osmotic pump should be a thin membrane. Arguments are provided that support the use of a volatile electrolyte. For the magnetohydrodynamic case, a brief investigation is provided. A quasi-one-dimensional hydromagnetic duct flow model is used. This hydromagnetic model is extended to approximate flow effects unique to heat pipes. When combined with a suitable heat pipe model, it is found that there is no performance gain for the case considered. In fact, there are serious pressure-distribution problems that have not been previously recognized. Potential solutions to these pressure-distribution problems are suggested

  11. Electro-Osmotic Flow of Semidilute Polyelectrolyte Solutions

    OpenAIRE

    Uematsu, Yuki; Araki, Takeaki

    2013-01-01

    We investigate electro-osmosis in aqueous solutions of polyelectrolytes using mean-field equations. A solution of positively charged polyelectrolytes is confined between two negatively charged planar surfaces, and an electric field is applied parallel to the surfaces. When electrostatic attraction between the polymer and the surface is strong, the polymers adhere to the surface, forming a highly viscous adsorption layer that greatly suppresses the electro-osmosis. Conversely, electro-osmosis ...

  12. Experimental Verification of Overlimiting Current by Surface Conduction and Electro-osmotic Flow in Microchannels

    CERN Document Server

    Nam, Sungmin; Heo, Joonseong; Lim, Geunbae; Bazant, Martin Z; Sung, Gunyong; Kim, Sung Jae

    2014-01-01

    Possible mechanisms of overlimiting current in unsupported electrolytes, exceeding diffusion limitation, have been intensely studied for their fundamental significance and applications to desalination, separations, sensing, and energy storage. In bulk membrane systems, the primary physical mechanism is electro-convection, driven by electro-osmotic instability on the membrane surface. It has recently been predicted that confinement by charged surfaces in microchannels or porous media favors two new mechanisms, electro-osmotic flow (EOF) and surface conduction (SC), driven by large electric fields in the depleted region acting on the electric double layers on the sidewalls. Here, we provide the first direct evidence for the transition from SC to EOF above a critical channel height, using in situ particle tracking and current-voltage measurements in a micro/nanofluidic device. The dependence of the over-limiting conductance on channel depth (d) is consistent with theoretical predictions, scaling as d^-1 for SC a...

  13. Effect of Electro-Osmotic Flow on Energy Conversion on Superhydrophobic Surfaces

    CERN Document Server

    Seshadri, Gowrishankar

    2013-01-01

    It has been suggested that superhydrophobic surfaces, due to the presence of a no-shear zone, can greatly enhance transport of surface charges, leading to a considerable increase in the streaming potential. This could find potential use in micro-energy harvesting devices. In this paper, we show using analytical and numerical methods, that when a streaming potential is generated in such superhydrophobic geometries, the reverse electro-osmotic flow and hence current generated by this, is significant. A decrease in streaming potential compared to what was earlier predicted is expected. We also show that, due to the electro-osmotic streaming-current, a saturation in both the power extracted and efficiency of energy conversion is achieved in such systems for large values of the free surface charge densities. Nevertheless, under realistic conditions, such microstructured devices with superhydrophobic surfaces have the potential to even reach energy conversion efficiencies only achieved in nanostructured devices so ...

  14. Anisotropic electro-osmotic flow over super-hydrophobic surfaces

    OpenAIRE

    Bahga, Supreet S.; Vinogradova, Olga I.; Bazant, Martin Z.

    2009-01-01

    Patterned surfaces with large effective slip lengths, such as super-hydrophobic surfaces containing trapped gas bubbles, have the potential to greatly enhance electrokinetic phenomena. Existing theories assume either homogeneous flat surfaces or patterned surfaces with thin double layers (compared to the texture correlation length) and thus predict simple surface-averaged, isotropic flows (independent of orientation). By analyzing electro-osmotic flows over striped slip-stick surfaces with ar...

  15. Augmentation of peristaltic microflows through electro-osmotic mechanisms

    International Nuclear Information System (INIS)

    The present work aims to theoretically establish that the employment of an axial electric field can substantially augment the rate of microfluidic transport occurring in peristaltic microtubes. For theoretical analysis, shape evolution of the tube is taken to be arbitrary, except for the fact that the characteristic wavelength is assumed to be significantly greater than the average radius of cross section. First, expressions for the velocity profile within the tube are derived and are subsequently utilized to obtain variations in the net flow rate across the same, as a function of the pertinent system parameters. Subsequently, the modes of interaction between the electro-osmotic and peristaltic mechanisms are established through the variations in the time-averaged flow rates for zero pressure rise and the pressure rise for zero time-averaged flow rates, as expressed in terms of the occlusion number, characteristic electro-osmotic velocity and the peristaltic wave speed. From the simulation predictions, it is suggested that a judicious combination of peristalsis and an axial electrokinetic body force can drastically enhance the time-averaged flow rate, provided that the occlusion number is relatively small

  16. Electro-osmotic flow of a second-grade fluid in a porous microchannel subject to an AC electric field

    Institute of Scientific and Technical Information of China (English)

    MISRA J.C.; CHANDRA S.

    2013-01-01

    Studies on electro-osmotic flows of various types of fluids in microcharmel are of great importance owing to their multifold applications in the transport of liquids,particularly when the ionized liquid flows with respect to a charged surface in the presence of an external electric field.In the case of viscoelastic fluids,the volumetric flow rate differs significantly from that of Newtonian fluids,even when the flow takes place under the same pressure gradient and the same electric field.With this end in view,this paper is devoted to a study concerning the flow pattern of an electro-osmotic flow in a porous microchannel,which is under the action of an alternating electric field.The influence of various rheologieal and electro-osmotic parameters,e.g.,the Reynolds number,Debye-Huckel parameter,shape factor and fluid viscoelasticity on the kinematics of the fluid,has been investigated for a second-grade viscoelastic fluid.The problem is first treated by using analytical methods,but the quantitative estimates are obtained numerically with the help of the software MATHEMATICA.The results presented here are applicable to the cases where the channel height is much greater than the thickness of the electrical double layer comprising the Stern and diffuse layers.The study reveals that a larger value of the Debye-Huckel parameter creates sharper profile near the wall and also that the velocity of electro-osmotic flow increases as the permeability of the porous microchannel is enhanced.The study further shows that the electro-osmotic flow dominates at lower values of Reynolds number.The results presented here will be quite useful to validate the observations of experimental investigations on the characteristics of electro-osmotic flows and also the results of complex numerical models that are necessary to deal with more realistic situations,where electro-osmotic flows come into the picture,as in blood flow in the micro-circulatory system subject to an electric field.

  17. Electro-osmotic fluxes in multi-well electro-remediation processes.

    Science.gov (United States)

    López-Vizcaíno, Rubén; Sáez, Cristina; Mena, Esperanza; Villaseñor, Jose; Cañizares, Pablo; Rodrigo, Manuel A

    2011-01-01

    In recent years, electrokinetic techniques on a laboratory scale have been studied but few applications have been assessed at full-scale. In this work, a mock-up plant with two rows of three electrodes positioned in semipermeable electrolyte wells has been used to study the electro-osmotic flux distribution. Water accumulated in the cathodic wells when an electric voltage gradient was applied between the two electrode-well rows. Likewise, slight differences in the water flux were observed depending on the position and number of electrodes used and on the voltage gradient applied. Results show that the electro-osmotic flow did not increase proportionally with the number of electrodes used. During the start-up of the study, there was an abrupt change in the current density, pH and conductivity of the soil portions closest to electrodic wells due to electrokinetic processes. These differences can be explained in terms of the complex current distributions from anode and cathode rows. PMID:22029697

  18. Electro-osmotic pumping and ion-concentration polarization based on conical nanopores

    Science.gov (United States)

    Yeh, Hung-Chun; Chang, Chih-Chang; Yang, Ruey-Jen

    2015-06-01

    A numerical investigation is performed into the characteristics of an electro-osmotic pump consisting of a negatively charged conical nanopore. It is shown that the dependence of the flow rectification effect on the bias direction is the reverse of that of the ion current rectification effect. Moreover, the nozzle mode (i.e., the bias is applied from the base side of the nanopore to the tip side) has a higher flow rate compared to the diffuser mode (i.e., the bias is applied from the tip side of the nanopore to the base side). The results showed that the ion-concentration polarization effect occurred inside the conical nanopore, resulting in surface conduction dominating in the ionic current. The ions inside the nanopore are depleted and enriched under the nozzle mode and the diffuser mode, respectively. As a result, the electro-osmotic pump yields a greater pumping pressure, flow rate, and energy conversion efficiency when operating in the nozzle mode. In addition, we also investigated the flow rate rectification behavior for the conical nanopore. The best flow rate rectification factor in this work is 2.06 for an electrolyte concentration of 10-3M .

  19. Analysis of electro-osmotic flow in a microchannel with undulated surfaces

    CERN Document Server

    Yoshida, Hiroaki; Washizu, Hitoshi

    2016-01-01

    The electro-osmotic flow through a channel between two undulated surfaces induced by an external electric field is investigated. The gap of the channel is very small and comparable to the thickness of the electrical double layers. A lattice Boltzmann simulation is carried out on the model consisting of the Poisson equation for electrical potential, the Nernst--Planck equation for ion concentration, and the Navier--Stokes {\\color{black}equations} for flows of the electrolyte solution. An analytical model that predicts the flow rate is also derived under the assumption that the channel width is very small compared with the characteristic length of the variation along the channel. The analytical results are compared with the numerical results obtained by using the lattice Boltzmann method. In the case of a constant surface charge density along the channel, the variation of the channel width reduces the electro-osmotic flow, and the flow rate is smaller than that of a straight channel. In the case of a surface ch...

  20. Applications of Electro-Osmotic Transport in the Processing of Textiles

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.; Krueger, R.; Hopper, R.; Cherepy, N.

    1999-11-29

    We report development of a pilot process for the industrial rinsing of fabrics. This process combines hydraulic (pressure-driven) transport with electro-osmotic transport. It reduces the total amount of water required in certain rinsing operations by a factor of about five. Cotton exhibits an electro-osmotic transport coefficient of about 6 x 10{sup -9} m{sup 2}/s-V resulting from a partial ionization of hydroxyl groups on the cellulose polymer substrate. This process applies a field transverse to the fabric to effect the movement of water in the spaces between the 10 {micro}m cotton fibers which constitute the yam. The field strength is adjusted so that the induced electro-osmotic flux is comparable to a pressure-driven flux, which moves preferentially in the more open channels between the yams. For a fixed current density, solution conductivity and electro-osmotic transport vary inversely. The process is most practical for removal of liquids of relatively low conductivity (<500 {micro}S/cm). For removal of solutions of conductivity greater than 1200 {micro}S/cm, the rate of electro-osmotic flow may be too low to benefit the rinsing process if current densities are restricted to practical levels of about 30 mA/cm{sup 2}. Electra-osmotic transport may have important applications in wet processing of extremely fine textiles, such as micro fiber fabrics. In addition to rinsing, electro-osmotic transport may also be used to speed the penetration of chemicals and dyestuffs that are applied to the surface of wet textiles.

  1. Oscillatory electro-osmotic flow through a slit channel with slipping stripes on walls

    International Nuclear Information System (INIS)

    A theoretical model is presented in this paper for time-oscillating electro-osmotic flow through a plane channel bounded by two parallel plates, which are patterned with periodic stripes of distinct hydrodynamic slippage and wall potential. The flow is driven by oscillatory pressure gradient and electric field of the same frequency in the axial direction. Flows that are longitudinal or transverse to the stripes are investigated. Based on the Debye–Hückel approximation, and assuming Stokes flow, the electric potential and the velocity fields are found by the methods of eigenfunction expansion and point collocation. The phenomenological coefficients of the Onsager relations for the fluid and current fluxes are deduced as functions of the channel height, the area fraction of wall with slippage, the intrinsic slip length, the Debye parameter, the zeta potentials and the oscillation parameter. Considering several kinds of wall patterns, we extend the theoretical limits in the steady-flow regime to the oscillatory-flow regime. For a uniformly charged wall, the effective slip length obtained from the hydrodynamic problem can still be used directly in the electro-osmotic flow as if the wall were uniformly slipping. When the slipping stripes are perfectly slipping but uncharged, the presence of such stripes will always have a decreasing effect on the streaming conductance, unlike the steady case in which it gives no net effect on the flow in the limit of a very thin double layer. Furthermore, we confirm the presence of a threshold frequency, beyond which the flow will diminish significantly. The slipping fraction of the wall will always introduce a phase lag to the response and lower the threshold frequency. Increasing the wall potential in the presence of slippage can appreciably increase the streaming conductance and the phase lag. (paper)

  2. Low-frequency oscillations of the impedance of electrolyte moving in an electro-osmotic regime

    Science.gov (United States)

    Kompan, M. E.; Malyshkin, V. G.; Goffman, V. G.

    2014-07-01

    The impedance of a liquid electrolyte has been studied under the conditions of electro-osmotic flow. It is found that the impedance exhibits oscillations in the region of subhertz frequencies, which are related to resonant mechanical oscillations arising in the flow. Assumptions concerning the type of these resonant oscillations are formulated based on the observed spectrum of impedance oscillations.

  3. Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

    OpenAIRE

    Norihisa Miki; Koichi Hishida; Reiko Kuriyama; Yohei Sato; Yosuke Koga

    2013-01-01

    Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD) plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF) is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined ...

  4. Fabrication and study of AC electro-osmotic micropumps

    Science.gov (United States)

    Guo, Xin

    In this thesis, microelectrode arrays of micropumps have been designed, fabricated and characterized for transporting microfluid by AC electro-osmosis (ACEO). In particular, the 3D stepped electrode design which shows superior performance to others in literature is adopted for making micropumps, and the performance of such devices has been studied and explored. A novel fabrication process has also been developed in the work, realizing 3D stepped electrodes on a flexible substrate, which is suitable for biomedical use, for example glaucoma implant. There are three major contributions to ACEO pumping in the work. First, a novel design of 3D "T-shaped" discrete electrode arrays was made using PolyMUMPsRTM process. The breakthrough of this work was discretizing the continuous 3D stepped electrodes which were commonly seen in the past research. The "T-shaped" electrodes did not only create ACEO flows on the top surfaces of electrodes but also along the side walls between separated electrodes. Secondly, four 3D stepped electrode arrays were designed, fabricated and tested. It was found from the experiment that PolyMUMPsRTM ACEO electrodes usually required a higher driving voltage than gold electrodes for operation. It was also noticed that a simulation based on the modified model taking into account the surface oxide of electrodes showed a better agreement with the experimental results. It thus demonstrated the possibility that the surface oxide of electrodes had impact on fluidic pumping. This methodology could also be applied to metal electrodes with a native oxide layer such as titanium and aluminum. Thirdly, a prototype of the ACEO pump with 3D stepped electrode arrays was first time realized on a flexible substrate using Kapton polyimide sheets and packaged with PDMS encapsulants. Comprehensive experimental testing was also conducted to evaluate the mechanical properties as well as the pumping performance. The experimental findings indicated that this fabrication

  5. Electro-optical detection of charged particles

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO sub 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  6. Particle and droplet dynamics and separation in AC electro-osmotic micropumps

    International Nuclear Information System (INIS)

    Typical tasks in life--sciences are the transport of small amounts of liquids as well as the segregation of suspended biological cells or particles in the microfluidic environment. In the last decade alternating-current electro-osmotic (ACEO) pumping has been found to be an effective means for transporting conductive fluids in microfluidic channels. The ACEO pumping channel is characterized by its configuration of periodic interdigitated electrode fingers on the channel bottom. If a harmonic voltage is applied, an electric double layer develops adjacent to the electrodes that electrically screens the applied potential. The motion of the charged surface layer due to the remaining electric field results in a net flow in the channel. This work proposes to use the ACEO pump not only for the transport of liquids but also for the systematic manipulation and separation of immersed particles. In order to achieve this an extensive study of the relevant forces and dynamics of particles and droplets in the resulting electro-kinetic channel flow is done. This work therefore analyzes the electric and the flow field by means of the finite element method and investigates the size and density dependent particle motion as a function of magnitude and frequency of the applied voltage. Furthermore, the deformation of droplets in the electrokinetic flow is investigated. Their motion is therefore analyzed by means of three-dimensional finite element computations of the respective two-phase flow, where surface tension forces and electrical stresses on the interface between droplet and carrier fluid are regarded. In the course of this work it is shown, that suspended particles and droplets are influenced by the interplay of viscous fluid drag, gravitation, surface tension and dielectrophoretic forces. Therein, the significant dependance of these forces on the particle properties allows for the separation with respect to mass--density and size. Based on this knowledge, channel designs are

  7. Electro-osmotic pumping and ionic conductance measurements in porous membranes

    Science.gov (United States)

    Vajandar, Saumitra K.

    Electro-osmotic (EO) pumps directly convert electrical energy into fluids' kinetic energy, which have many advantages such as a simple and compact structure, no mechanical moving parts, and easy integration. In general, it is easy for EO pumps to generate enough pressure but it has been a challenge for EO pumps to produce a high flowrate. EO pumps have found applications in various micro-/nano-electro-mechanical systems (MEMS/NEMS) and have the potential to impact a variety of engineering fields including microelectronics cooling and bio-analytical systems. This dissertation focuses on the design, fabrication and characterization of EO pumps based on two novel porous membrane materials: SiO2-coated anodic porous alumina and SiNx-coated porous silicon. High quality porous alumina membranes of controllable pore diameters in the range of 30-100 nm and pore lengths of 60-100 mum were fabricated by electrochemical anodization. The pores are straight, uniform and hexagonally close-packed with a high porosity of up to 50%. The inner surface of the pore was coated with a thin layer (˜5 nm) of SiO2 conformally to achieve a high zeta potential. The EO pumping flowrate of the fabricated anodic alumina membranes, coated and uncoated, was experimentally measured. Results indicate that the high zeta potential of the SiO2 coating increases the pumping flowrate even though the coating reduces the porosity of the membrane. The nanostructured SiO2-coated porous anodic alumina membranes can provide a normalized flowrate of 0.125 ml/min/V/cm2 under a low effective applied voltage of 3 V, which sets a record high normalized flowrate under low applied voltage. To realize field effect control of EO pumping, we designed and fabricated SiNx-coated porous silicon membranes with the silicon core as the electrode to apply a transverse gate potential. The gate potential will modulate the zeta potential of the pore wall and thereby provide control over the EO flowrate. The membranes were

  8. EFFECT OF AQUEOUS PHASE PROPERTIES ON CLAY PARTICLE ZETA POTENTIAL AND ELECTRO-OSMOTIC PERMEABILITY: IMPLICATIONS FOR ELECTRO-KINETIC SOIL REMEDIATION PROCESSES

    Science.gov (United States)

    The influence of aqueous phase properties (pH, ionic strength and divalent metal ion concentration) on clay particle zeta potential and packed-bed electro-osmotic permeability was quantified. Although pH strongly altered the zeta potential of a Georgia kaolinite, it did not signi...

  9. Ultrafast High-pressure AC Electro-osmotic Pumps for Portable Biomedical Microfluidics

    CERN Document Server

    Huang, Chien-Chih; Thorsen, Todd

    2009-01-01

    This paper details the development of an integrated AC electro-osmotic (ACEO) microfluidic pump for dilute electrolytes consisting of a long serpentine microchannel lined with three dimensional (3D) stepped electrode arrays. Using low AC voltage (1 Volt rms, 1 kHz), power (5 mW) and current (3.5 mA) in water, the pump is capable of generating a 1.4 kPa head pressure, a 100-fold increase over prior ACEO pumps, and a 1.37 mm/sec effective slip velocity over the electrodes without flow reversal. The integrated ACEO pump can utilize low ionic strength solutions such as distilled water as the working solution to pump physiological strength (100 mM) biological solutions in separate microfluidic devices, with potential applications in portable or implantable biomedical microfluidic devices. As a proof-of-concept experiment, the use of the ACEO pumps for DNA hybridization in a microfluidic microarray is demonstrated.

  10. Suppression of nano-channel ion conductance by electro-osmotic flow

    CERN Document Server

    Liu, Yang; Zhu, Xin; Ran, Qiushi; Dutton, Robert

    2016-01-01

    This theoretical study concerns a basic understanding of ion transport in nano-channels that have weakly overlapping electric double layers. Numerical simulations reveal that the electro-osmotic flow (EOF) interplays with the concentration-polarization process and drives the ion depletion zone into the channels, thus significantly suppressing the channel conductance. The conductance may be restored at high electrical biases in the presence of recirculating vortices within the channels. Further analysis are conducted based on a 1-D, long channel model, and analytic expressions derived to quantitatively account for the EOF-driven ion depletion process. A limiting-conductance behavior is revealed as intrinsically different from the classical limiting-current behavior.

  11. Non-steady electro-osmotic flow of a micropolar fluid in a microchannel

    International Nuclear Information System (INIS)

    We formulated the initial-boundary-value problem of non-steady electro-osmotic flow of a micropolar fluid in a rectangular microchannel of height much larger than the Debye length and length much larger the height. Solving the governing differential equations numerically when a spatially uniform electric field is applied as an impulse of finite magnitude, we found that the effect is instantaneous on the flow, just as for simple Newtonian fluids. The decay times of the fluid velocity and the microrotation, however, are smaller in micropolar fluids than in simple Newtonian fluids. The maximum magnitude of microrotation decreases as the micropolarity increases. The effect of microrotation on the stress tensor is more dominant than that of the fluid speed, and a threshold effect with respect to the magnitude of the zeta potential is evident in the spatial profile of the couple stress tensor. We expect similar trends even when the applied electric field varies over some finite interval of time.

  12. Experimental and theoretical investigations of non-Newtonian electro-osmotic driven flow in rectangular microchannels.

    Science.gov (United States)

    Huang, Yi; Chen, Juzheng; Wong, TeckNeng; Liow, Jong-Leng

    2016-07-20

    With the development of microfluidics, electro-osmotic (EO) driven flow has gained intense research interest as a result of its unique flow profile and the corresponding benefits in its application in the transportation of sensitive samples. Sensitive samples, such as DNA, are incapable of enduring strong flow shear induced by conventional hydrodynamic driven methods. EO driven flow is thus a niche area. However, even though there are a few research studies focusing on bio-fluidic samples related to EO driven flow, the majority of them are merely theoretical modeling without solid evidence from experiments due to the inherent complex rheological behavior of the bio-fluids. Challenges occur when the EO driven mechanism meets with complex rheology; vital questions such as can the zeta potential still be assumed to be constant when dealing with fluids with complex rheology? and "Does the shear thinning effect enhance electro-osmotic driven flow?" need to be answered. We conducted experiments using current monitoring and microscopy fluorescence methods, and developed a theoretical model by coupling a generalized Smoluchowski approach with the power-law constitutive model. We calculated the zeta potential and compared the experimental results with modeling to answer the questions. The results show a reduction of zeta potential in the presence of PEO aqueous solutions. A constant zeta potential is also indicated by varying the PEO concentration and the electric field strength.The shear thinning effect is also addressed via experimental data and theoretical calculations. The results show a promising enhancement of the EO driven velocity due to the shear thinning effect. PMID:27381295

  13. Modified Bernoulli Equation for Use with Combined Electro-Osmotic and Pressure-Driven Microflows

    CERN Document Server

    Adams, Thomas M

    2012-01-01

    In this paper we present electro-osmotic (EO) flow within a more traditional fluid mechanics framework. Specifically, the modified Bernoulli equation (viz. the energy equation, the mechanical energy equation, the pipe flow equation, etc.) is shown to be applicable to EO flows if an electrical potential energy term is also included. The form of the loss term in the modified Bernoulli equation is unaffected by the presence of an electric field; i.e., the loss term still represents the effect of wall shear stress, which can be represented via a friction factor. We show that that the friction factor for pure EO flow (no applied pressure gradient) varies inversely with the Reynolds number based on the Debeye length of the electric double layer. Expressions for friction factor for combined laminar pressure-driven and EO flow are also given. These are shown to be functions of Reynolds number and geometry, as well as the relative strength of the applied electric field to the applied pressure gradient.

  14. Flow patterning in Hele-Shaw configurations using non-uniform electro-osmotic slip

    Science.gov (United States)

    Boyko, Evgeniy; Rubin, Shimon; Gat, Amir D.; Bercovici, Moran

    2015-10-01

    We present an analytical study of electro-osmotic flow in a Hele-Shaw configuration with non-uniform zeta potential distribution. Applying the lubrication approximation and assuming thin electric double layer, we obtain a pair of uncoupled Poisson equations for the pressure and depth-averaged stream function, and show that the inhomogeneous parts in these equations are governed by gradients in zeta potential parallel and perpendicular to the applied electric field, respectively. We obtain a solution for the case of a disk-shaped region with uniform zeta potential and show that the flow field created is an exact dipole, even in the immediate vicinity of the disk. In addition, we study the inverse problem where the desired flow field is known and solve for the zeta potential distribution required in order to establish it. Finally, we demonstrate that such inverse problem solutions can be used to create directional flows confined within narrow regions, without physical walls. Such solutions are equivalent to flow within channels and we show that these can be assembled to create complex microfluidic networks, composed of intersecting channels and turns, which are basic building blocks in microfluidic devices.

  15. Electro-osmotically driven MHD flow and heat transfer in micro-channel

    Science.gov (United States)

    Shit, G. C.; Mondal, A.; Sinha, A.; Kundu, P. K.

    2016-05-01

    A theoretical analysis is presented for electro-osmotic flow (EOF) of blood in a hydrophobic micro-channel with externally applied magnetic field. The lumen of micro-channels is assumed to be porous medium in addition to the consideration of permeability of the channel walls. The effects of slip velocity and thermal-slip are taken into consideration. The governing equations in the electrical double layer (EDL) together with the Poisson-Boltzmann equation and the body force exerted by the applied potential are furthermore considered. The flow is governed by the non-Newtonian viscoelastic fluid model. These equations along with the thermal energy equation are approximated by assuming that the channel height is much greater than the thickness of electrical double layer consisting the stern and diffusive layers. The problem is solved analytically and the computed results have presented graphically for various values of the dimensionless parameters. The results presented here have significant impact on the therapeutic treatment in hyperthermia as well as in controlling blood flow and heat transfer in micro-channels.

  16. Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

    Directory of Open Access Journals (Sweden)

    Norihisa Miki

    2013-03-01

    Full Text Available Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined glass surfaces, which includes surface roughness that is determined by the manufacturing processes. In this paper, we investigate the effect of micromaching processes on the glass surface topography and the EOF mobility. We prepared glass surfaces by either wet etching or by NLD plasma etching, investigated the surface topography using atomic force microscopy, and attempted to correlate it with EOF generated in the micro-channels of the machined glass. Experiments revealed that the EOF mobility strongly depends on the surface roughness, and therefore upon the fabrication process used. A particularly strong dependency was observed when the surface roughness was on the order of the electric double layer thickness or below. We believe that the correlation described in this paper can be of great help in the design of micro/nano fluidic devices.

  17. Heat-transfer enhancement in AC electro-osmotic micro-flows

    Science.gov (United States)

    Liu, Z. P.; Speetjens, M. F. M.; Frijns, A. J. H.; van Steenhoven, A. A.

    2012-11-01

    Heat transfer in micro-flows is essential to emerging technologies as advanced microelectronics cooling systems and chemical processes in lab-on-a-chip applications. The present study explores the potential of AC electro-osmotic (ACEO) flow forcing, a promising technique for the actuation and manipulation of micro-flows, for heat-transfer enhancement. Subjects of investigation include the 3D flow structure due to ACEO forcing via an array of electrodes in a micro-channel by way of 3D velocity measurements. Presence and properties of vortical structures of the 3D flow are quantified in laboratory experiments. Typical outcomes of the experimental study result from a number of 3D particle trajectories obtained by using 3D micro-Particle-Tracking Velocimetry (3D μ-PTV). The steady nature of the flow enables combination of results from a series of measurements into one dense data set. This facilitates accurate evaluation of quantities relevant for heat transfer by data-processing methods. The primary circulation is given above one half of an electrode in terms of the spanwise component of vorticity. The outline of the vortex boundary is determined via the eigenvalues of the strain-rate tensor. To estimate convective heat transfer, wall shear rate above one half of an electrode is quantitatively analyzed as function of voltage amplitude and frequency. These results yield first insights into the characteristics of 3D ACEO flows and ways to exploit and manipulate them for heat-transfer enhancement.

  18. Numerical analysis of finite Debye-length effects in induced-charge electro-osmosis

    DEFF Research Database (Denmark)

    Gregersen, Misha Marie; Andersen, Mathias Bækbo; Soni, G.; Meinhart, C.; Bruus, Henrik

    2009-01-01

    For a microchamber filled with a binary electrolyte and containing a flat unbiased center electrode at one wall, we employ three numerical models to study the strength of the resulting induced-charge electro-osmotic (ICEO) flow rolls: (i) a full nonlinear continuum model resolving the double layer......, (ii) a linear slip-velocity model not resolving the double layer and without tangential charge transport inside this layer, and (iii) a nonlinear slip-velocity model extending the linear model by including the tangential charge transport inside the double layer. We show that, compared to the full...... model, the slip-velocity models significantly overestimate the ICEO flow. This provides a partial explanation of the quantitative discrepancy between observed and calculated ICEO velocities reported in the literature. The discrepancy increases significantly for increasing Debye length relative to the...

  19. Simulation of an ac electro-osmotic pump with step microelectrodes

    Science.gov (United States)

    Kim, Byoung Jae; Lee, Seung-Hyun; Rezazadeh, Soghra; Sung, Hyung Jin

    2011-05-01

    Pumps with step microelectrodes subjected to an ac voltage are known to have faster pumping rates than those with planar asymmetric microelectrodes. The driving force for pumping in these systems is ac electro-osmosis. This paper aims to understand the flow behaviors of pumps with step microelectrodes by using a realistic model applicable to high external voltages. This model takes the steric effect due to the finite sizes of ions into account and copes with the exponential sensitivity of the counterion concentration to voltage. The effects on the pumping flow rate of varying the pump parameters were investigated. The geometrical parameters were optimized, and the effects of varying the ac frequency and amplitude were examined. The electrical potential of the fluid and the electrical charge at the electrode surface were solved simultaneously, and the Stokes equation was used to describe the fluid flow.

  20. Ion fluxes and electro-osmotic fluid flow in electrolytes around a metallic nanowire tip under large applied ac voltage.

    Science.gov (United States)

    Poetschke, M; Bobeth, M; Cuniberti, G

    2013-09-10

    Motivated by the analysis of electrochemical growth of metallic nanowires from solution, we studied ion fluxes near nanoelectrodes in a binary symmetric electrolyte on the basis of the modified Poisson-Nernst-Planck equations in the strongly nonlinear region at large applied ac voltage. For an approximate calculation of the electric field near the nanowire tip, concentric spherical blocking electrodes were considered with radius of the inner electrode being of typically a few ten nanometers. The spatiotemporal evolution of the ion concentrations within this spherical model was calculated numerically by using the finite element method. The potential drop at the electric double layer, the electric field enhancement at the electrode surface, and the field screening in the bulk solution were determined for different bulk concentrations, ac voltages, and frequencies. The appearance of ac electro-osmotic fluid flow at the tip of a growing metallic nanowire is discussed, based on an estimation of the body force in the liquid near the nanowire tip, which was modeled by a cylinder with hemispherical cap. Electric field components tangential to the electrode surface exist near the contact between cylinder and hemisphere. Our analysis suggests that ac electro-osmotic flow causes an additional convective transport of metal complexes to the tip of the growing metal nanowire and thus affects the nanowire growth velocity. PMID:23927385

  1. In situ electro-osmotic cleanup of tar contaminated soil—Removal of polycyclic aromatic hydrocarbons

    KAUST Repository

    Lima, Ana T.

    2012-12-01

    An in situ electro-osmosis experiment was set up in a tar contaminated clay soil in Olst, the Netherlands, at the site of a former asphalt factory. The main goal of this experiment was to remove polycyclic aromatic hydrocarbons (PAHs) from the contaminated clay layer by applying an electric gradient of 12 V m-1 across the soil over an electrode distance of 1 m. With the movement of water by electro-osmosis and the addition of a non-ionic surfactant (Tween 80), the non-polar PAHs were dragged along by convection and removed from the fine soil fraction. Soil samples were taken at the start and after 159 days at the end of the experiment. Water at the electrode wells was sampled regularly during the course of the experiment. The results reflect the heterogeneity of the soil characteristics and show the PAH concentrations within the experimental set up. After first having been released into the anolyte solution due to extraction by Tween 80 and subsequent diffusion, PAH concentrations increased significantly in the electrode reservoirs at the cathode side after 90 days of experiment. Although more detailed statistical analysis is necessary to quantify the efficiency of the remediation, it can be concluded that the use of electro-osmosis together with a non-ionic surfactant is a feasible technique to mobilize non-polar organic contaminants in clayey soils. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.

  2. Electro-Optical Detection of Charged Particle Beams

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R C; Lazarus, D M; Magurno, B; Srinivasan-Rao, T; Tsang, Thomas; Usack, V

    1999-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the propagation of laser light in a birefringent crystal at the Brookhaven National Laboratory Accelerator Test Facility. Polarized infrared light was coupled to a LiNbO3 crystal through a polarization maintaining fiber of 4 micron diameter. An electron beam in 10ps bunches of 1mm diameter was scanned across the crystal. The modulation of the laser light during passage of the electron beam was observed using a photodiode with 45GHz bandwidth. The fastest rise time measured, 120ps, was made in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. Both polarization dependent and polarization independent effects were observed. This technology holds promise of greatly improved spatial and temporal resolution of charged particle beams.

  3. Asymmetric flows over symmetric surfaces: capacitive coupling in induced-charge electro-osmosis

    International Nuclear Information System (INIS)

    We report curious asymmetric induced-charge electro-osmotic (ICEO) flows over a symmetric, planar gate electrode under applied ac electric fields, whereas symmetric, counter-rotating rolls are expected. Furthermore, the asymmetric component of the flow is consistently directed towards the grounded electrode. We propose that capacitive coupling of the gate electrode to the microscope stage-a comparatively large equipotential surface that acts effectively as a ground-is responsible for this symmetry breaking. This stray capacitance drives the formation of a double layer whose zeta potential is proportional to the potential drop from the electrolyte directly above the gate electrode to the external stage. Therefore, the charge in this 'stray' double layer varies in phase with the driving field, resulting in a rectified, steady flow as with standard ICEO. We experimentally vary the stray capacitance, the electric potential of the stage and the location of the gate electrode, and find that the effect on the stray flow is qualitatively consistent with the predictions of the proposed mechanism. In the process, we demonstrate that capacitive coupling offers an additional means of manipulating fluid flow over a polarizable surface.

  4. 异性纳米通道中NaCl水溶液电渗输运特性%MD Simulation of Electro-Osmotic Characteristics of NaC1 Solution in Different Nano-Tubes

    Institute of Scientific and Technical Information of China (English)

    蒋洁; 陈永平; 郝英立

    2011-01-01

    The flow characteristics of NaCl solution in different nanotubes were investigated. The tubes differ in charge. One has no charge and the other has negative charge. The distribution of velocity, density, viscosity and thermal conductivity were got. It is found the Na+ is absorbed by charged wall, Cl- is expelled to the center of the tube. Na+ and water travel towards the cathode and Cl-travels towards the anode. Ions travel as electro-osmotic flow and water travels as a mixture of electro-osmotic flow and dragged flow. The order of particles in NaCl solution and diffusion are strengthened by charged wall. The thermal conductivity near the wall is larger than in the center area.%采用分子动力学方法模拟了电场驱动下纳米通道中NaCl水溶液的电渗输运特性,壁面为无电荷和带有负电荷两种情况,统计了速度、密度、黏度和热传导系数的分布规律.在壁面电荷作用下,Na+被壁面吸附,Cl-聚集在通道中央;Na+与水分子朝电场负方向、Cl-朝电场正方向运动;Na+、Cl-呈电渗流动,水分子则较为复杂,呈电渗流和被离子拖拽混杂流动;在壁面作用下,水分子和Na+/Cl-的有序度、系统的自扩散系数增大;热传导系数分布呈靠近壁面处大,主流区小的特点.

  5. Theory and design method for electro-osmotic consolidation%电渗排水固结的设计理论和方法

    Institute of Scientific and Technical Information of China (English)

    庄艳峰

    2016-01-01

    探讨了电渗法处理大面积深厚软土地基的若干问题,包括:电极材料、能耗、电源功率、设计理论和方法。EKG材料的出现解决了电极腐蚀和电渗能耗过高的问题,现在电渗法在大面积应用中面临的是电源功率要求过高的问题,该问题可以通过轮询通电的方法解决。依据电渗能级梯度理论提出了电渗排水固结的设计方法。时间因子和流量系数是电渗设计方法中的两个关键参数,其中流量系数具有较明显的模型尺寸效应,设计时需要进行修正。%The problems of electro-osmotic consolidation for large scale deep soft ground, including electrode, energy consumption, electric power, theory and design method, are discussed. Innovation of EKG materials has solved the problems of electrode corrosion and high energy consumption in electro-osmotic consolidation. High electric power demand is currently a new challenge for large scale application of electro-osmotic consolidation, and the solution will be the roll polling program embedded in novel designed electric power source. The design method based on the energy level gradient theory of electro-osmotic consolidation is proposed. The time factor and flow coefficient are the key parameters of the design method. The flow coefficient has distinct scale effect, and it needs to be corrected before applied in the design.

  6. Dispersion in oscillatory electro-osmotic flow through a parallel-plate channel with kinetic sorptive exchange at walls

    Institute of Scientific and Technical Information of China (English)

    吴朝安

    2014-01-01

    Dispersion in time-oscillatory electro-osmotic flows in a slit micro-channel under the effect of kinetic sorptive exchange at walls is theoretically investigated using the homogenization method. The two walls of the channel are considered to be made up of different materials, and therefore have different zeta potentials and sorption coefficients. A general expression for the Taylor disper-sion coefficient under different zeta potentials as well as various sorption conditions at the walls is derived analytically. The disper-sion coefficient is found to be dependent on the oscillation frequency, the Debye parameter, the species partition coefficient, the rea-ction kinetics and the ratio of the wall potentials. The results demonstrate that the presence of wall sorption tends to enhance the dispersion when the oscillation frequency is low, but the effect is negligible in high-frequency oscillatory flows. Moreover, it is found that the dispersion coefficient could be significantly changed by adjusting the relative wall potentials for low-frequency flows.

  7. Negatively charged hyperbranched polyglycerol grafted membranes for osmotic power generation from municipal wastewater.

    Science.gov (United States)

    Li, Xue; Cai, Tao; Chen, Chunyan; Chung, Tai-Shung

    2016-02-01

    Osmotic power holds great promise as a clean, sustainable and largely unexploited energy resource. Recent membrane development for pressure-retarded osmosis (PRO) is making the osmotic power generation more and more realistic. However, severe performance declines have been observed because the porous layer of PRO membranes is fouled by the feed stream. To overcome it, a negatively charged antifouling PRO hollow fiber membrane has been designed and studied in this work. An antifouling polymer, derived from hyperbranched polyglycerol and functionalized by α-lipoic acid and succinic anhydride, was synthesized and grafted onto the polydopamine (PDA) modified poly(ether sulfone) (PES) hollow fiber membranes. In comparison to unmodified membranes, the charged hyperbranched polyglycerol (CHPG) grafted membrane is much less affected by organic deposition, such as bovine serum albumin (BSA) adsorption, and highly resistant to microbial growths, demonstrated by Escherichia coli adhesion and Staphylococcus aureus attachment. CHPG-g-TFC was also examined in PRO tests using a concentrated wastewater as the feed. Comparing to the plain PES-TFC and non-charged HPG-g-TFC, the newly developed membrane exhibits not only the smallest decline in water flux but also the highest recovery rate. When using 0.81 M NaCl and wastewater as the feed pair in PRO tests at 15 bar, the average power density remains at 5.6 W/m(2) in comparison to an average value of 3.6 W/m(2) for unmodified membranes after four PRO runs. In summary, osmotic power generation may be sustained by properly designing and anchoring the functional polymers to PRO membranes. PMID:26630043

  8. Negatively Charged Hyperbranched Polyglycerol Grafted Membranes for Osmotic Power Generation from Municipal Wastewater

    KAUST Repository

    Li, Xue

    2015-11-18

    Osmotic power holds great promise as a clean, sustainable and largely unexploited energy resource. Recent membrane development for pressure-retarded osmosis (PRO) is making the osmotic power generation more and more realistic. However, severe performance declines have been observed because the porous layer of PRO membranes is fouled by the feed stream. To overcome it, a negatively charged antifouling PRO hollow fiber membrane has been designed and studied in this work. An antifouling polymer, derived from hyperbranched polyglycerol and functionalized by α-lipoic acid and succinic anhydride, was synthesized and grafted onto the polydopamine (PDA) modified poly(ether sulfone) (PES) hollow fiber membranes. In comparison to unmodified membranes, the charged hyperbranched polyglycerol (CHPG) grafted membrane is much less affected by organic deposition, such as bovine serum albumin (BSA) adsorption, and highly resistant to microbial growths, demonstrated by E. coli adhesion and S. aureus attachment. CHPG-g-TFC was also examined in PRO tests using a concentrated wastewater as the feed. Comparing to the plain PES-TFC and non-charged HPG-g-TFC, the newly developed membrane exhibits not only the smallest decline in water flux but also the highest recovery rate. When using 0.81 M NaCl and wastewater as the feed pair in PRO tests at 15 bar, the average power density remains at 5.6 W/m2 in comparison to an average value of 3.6 W/m2 for unmodified membranes after four PRO runs. In summary, osmotic power generation may be sustained by properly designing and anchoring the functional polymers to PRO membranes.

  9. Electrical Potential, Mass Transport and Velocity Distribution of Electro-osmotic Flow in a Nanochannel by Incorporating the Variation of Dielectric Constant of Aqueous Electrolyte Solution

    CERN Document Server

    Padidhapu, Rajendra; Brahmajirao, V

    2016-01-01

    We consider a coupled system of Navier Stokes, Maxwell Stefan and Poisson Boltzmann equations by incorporating the variation of dielectric constant, which governs the electro osmotic flow in nano channel, describing the evolution of the velocity, concentration and potential fields of dissolved constituents in an aqueous electrolyte solution. We apply the finite difference technique to solve one and two dimensional systems of these equations. The solutions give an extremely accurate prediction of the dielectric constant for a variety of salts and a wide range of concentrations.

  10. Macroscopic electric field and osmotic pressure in ultracentrifugal sedimentation-diffusion equilibria of charged colloids

    International Nuclear Information System (INIS)

    Sedimentation-diffusion (SD) equilibria from analytical ultracentrifugation of well-characterized charged silica spheres in ethanol deviate strongly from a barometric profile and demonstrate the existence and substantial effects of a recently predicted internal macroscopic electric field (van Roij 2003 J. Phys.: Condens. Matter 15 S3569). Experimental SD-profiles yield the gradient of the electrostatic potential energy of the colloids, which clearly manifests an almost homogeneous macroscopic electric field. Electrochemical Donnan potential measurements confirm a difference in electrical potential between the top and bottom of the profiles. A 'non-barometric' limiting law derived from electroneutrality explains the trends in the SD-profiles quite well. Our analysis of osmotic pressures (obtained from integrating SD-profiles) beyond this simple law includes, among other things, colloid-ion attractions and extra volume terms in the free energy

  11. Osmotic Properties of Charged Cylinders: Critical Evaluation of Counterion Condensation Theory

    OpenAIRE

    Hansen, Per Lyngs; Podgornik, Rudi; Parsegian, V. Adrian

    2000-01-01

    The osmotic coefficient of B-DNA in water may, in moderately dilute solutions, deviate as much as 100 % from predictions based on a simple 'counterion condensation' theory. We determine the results for osmotic properties via a cell model description of the ionic atmosphere near a cylindrical polyelectrolyte. The cell model predictions for the osmotic properties disagree with predictions based on simple condensation theory, but are in surprisingly good harmony with experimental findings. We ar...

  12. Analysis of metal ions migration to determine electro-osmotic flow for the in-situ cleanup of a tar-contaminated site

    KAUST Repository

    Lima, Ana T.

    2012-03-01

    An electro-osmosis experiment was set up on a former asphalt factory site, which is currently contaminated by tar, in Olst, the Netherlands. The main goal of this experiment was to remove polycyclic aromatic hydrocarbons (PAHs) from a contaminated clay layer by applying an electric gradient. But before calculating PAH removal, the direction and intensity of electro-osmosis have to be estimated. In field situations, tracers are used to get information about the water flow. In the present study, the inorganic elements concentration oscillations during electro-osmosis application are used as tracers. The experiment was set up in a clay layer, with the configuration 1m×1m×0.3m, at a depth of 4m below soil surface. Al, Ca, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Si, Ti and Zn concentrations were determined in 28 measurements and were performed during the experimental period of 159days. Then they were used in a first evaluation where auto and cross-correlations were analyzed to aid in the geochemical interpretation and select the most conservative elements. The second part of this study is devoted to estimate the migration of water based on the concentrations development of Cl - at the anode and Na + at the cathode. Electro-osmotic flow was estimated to be intense (2.9 -10 -9-2.18 -10 -8m -s -1) during the first 10 to 50days of experiment and to cease after this period. © 2012.

  13. Biquaternionic Model of Electro-Gravimagnetic Field, Charges and Currents. Law of Inertia

    CERN Document Server

    Alexeyeva, Lyudmila

    2016-01-01

    One the base of Maxwell and Dirac equations the one biquaternionic model of electro-gravimagnetic (EGM) fields is considered. The closed system of biquaternionic wave equations is constructed for determination of free system of electric and gravimagnetic charges and currents and generated by them EGM-field. By using generalized functions theory the fundamental and regular solutions of this system are determined and some of them are considered (spinors, plane waves, shock EGMwaves and others). The properties of these solutions are investigated.

  14. Multi-functional Lagrangian flow structures in three-dimensional ac electro-osmotic micro-flows

    International Nuclear Information System (INIS)

    Flow forcing by ac electro-osmosis (ACEO) is a promising technique for the actuation and manipulation of micro-flows. Utilization to date mainly concerns pumping and mixing. However, emerging micro-fluidic applications demand further functionalities. The present study explores the first ways to systematically realize this in three-dimensional (3D) micro-flows using ACEO. This exploits the fact that continuity 'organizes' Lagrangian fluid trajectories into coherent structures that geometrically determine the transport properties. Lagrangian flow structures typically comprise families of concentric tubular structures, acting both as transport barriers and as transport conduits, embedded in chaotic regions. Numerical simulations of representative case studies demonstrate that ACEO, possibly in combination with other forcing mechanisms, has the potential to tailor these features into multi-functional Lagrangian flow structures that can fulfill various transport purposes. This may greatly enhance the functionality and versatility of labs-on-a-chip.

  15. Electro-elastic fields due to a point charge in a flexoelectric medium

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rajdeep, E-mail: rsharma@exponent.com

    2015-10-01

    Flexoelectricity provides a two-way connection between strain gradients and polarization that is pronounced at the nanoscale for isotropic materials which cannot link electromechanically via piezoelectricity. In this paper, the general equations for an isotropic, flexoelectric material were formulated, with contributions from strain gradients included. The electromechanical fields associated with a point charge in an infinite medium were derived, and results for GaAs were obtained. Our formulation yields two electromechanical length-scales, instead of one obtained from previous theories, and enables us to capture local fields accurately. Results from this paper provide insight into the electro-mechanical behavior of materials with charged defects.

  16. Active Vector Separation Using Induced Charge Electro-osmosis with Polarizable Obstacle Arrays

    Science.gov (United States)

    Sugioka, Hideyuki

    2016-09-01

    Vector separation using obstacle post arrays is promising for various microfluidic applications. Here, we propose a novel active sieve using induced charge electro-osmosis (ICEO). By the multi-physics simulation technique based on the boundary element method combined with a thin electric double-layer approximation, we find that the active sieve having a polarizable post array shows excellent vector separation with dynamic size selectivity owing to the hydrodynamic interactions between the polarizable post array and the target particle. We consider that our separation device is useful for realizing innovative high-throughput biomedical systems with a simple structure.

  17. 电极间距和排水方式对电渗固结效果试验%Influence of electrode spacing and drainage mode on electro-osmotic consolidation

    Institute of Scientific and Technical Information of China (English)

    曾宏

    2015-01-01

    为了探讨淤泥电渗固结的最佳方式,开展了不同电极间距和排水方式的电渗对比试验,试验中对渗水量、土体沉降、电能消耗、含水率等指标进行了监测,得出了适合工程应用的电极间距为1.2 m,排水孔钻孔深度7.5 m,排水方式采用塑料排水板套砂袋组合体排水.工程应用实例表明:采用该电极间距和排水方式取得了良好的电渗固结效果.%In order to study the best mode of mud electro-osmotic consolidation,electro-osmotic tests were con-ducted with different electrode spacing and drainage modes. The observed indexes during tests include seepage wa-ter volume,soil mass settlement,electric energy consumption,water-content coefficient etc. According to the re-sults of tests,some indexes applicable for engineering were concluded,including a electrode spacing of 1.2m, drainage bore depth of 7.5m,composite drainage mode of plastic drainage plate in sand bag. Application of above conclusions in completed project has demonstrated good electro-osmotic consolidation effects.

  18. Newton's laws for a biquaternionic model of the electro-gravimagnetic field, charges, currents and their interactions

    OpenAIRE

    Alexeyeva, Lyudmila

    2011-01-01

    With use the Hamiltonian form of the Maxwell's equations one biquaternionic model for electro-gravimagnetic (EGM) field is offered. The equations of the interaction of EGM-fields, which are generated by different charge and current, are built. The field analogs of three Newton's laws are offered for free and interacting charge-currents, as well as total field of interaction. The invariance of these equations at Lorentz transformation is investigated, and, in particular, of the charge-current ...

  19. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, H., E-mail: haalghamdi@nu.edu.sa [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Faculty of Engineering, Najran University, Najran, P.O.Box 1988 (Saudi Arabia); Chen, G.; Vaughan, A. S. [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2015-12-15

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  20. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    International Nuclear Information System (INIS)

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology

  1. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Science.gov (United States)

    Alghamdi, H.; Chen, G.; Vaughan, A. S.

    2015-12-01

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  2. Electro-optical measurement of sub-ps structures in low charge electron bunches

    Science.gov (United States)

    Müller, F.; Peier, P.; Schlott, V.; Steffen, B.; Feurer, T.; Kuske, P.

    2012-07-01

    Electro-optical detection of THz coherent synchrotron radiation is a nondestructive method for measuring subpicosecond electron bunches or subpicosecond substructures on otherwise longer electron bunches. With a new diagnostic setup at the Swiss Light Source, which combines an amplified Yb fiber laser and a suitable GaP crystal, we demonstrate sampling as well as spectrally resolved single-shot measurements of sliced electron bunches containing as little as a few pC of charge. The single-shot measurements not only allow for a precise electric field characterization but also for a detailed analysis of the timing jitter between the electron bunch and the synchronized Yb fiber laser. The measurements of subsequent turns in the storage ring show distinct deviations from the simulations and we find strong indications that this discrepancy is caused by radiation loss through coherent synchrotron radiation itself, which is not included in many of today’s simulation codes.

  3. Electro-hydrodynamics near Hydrophobic Surfaces

    CERN Document Server

    Maduar, S R; Lobaskin, V; Vinogradova, O I

    2014-01-01

    We show that the dynamics of the electrostatic diffuse layer at the slippery hydrophobic surface depends strongly on the mobility of surface charges. For a hydrophobic surface with immobile charges the fluid transport is considerably amplified by the existence of a hydrodynamic slippage. In contrast, near the hydrophobic surface with mobile adsorbed charges it is also controlled by an additional electric force, which increases the shear stress at the slipping interface. To account for this we formulate electro-hydrodynamic boundary conditions at the slipping interface, which are applied to quantify electro-osmotic flows. Our theoretical predictions are fully supported by dissipative particle dynamics simulations with explicit charges. These results lead to a new general concept of zeta-potential of hydrophobic surfaces.

  4. In situ electric fields causing electro-stimulation from conductor contact of charged human.

    Science.gov (United States)

    Nagai, Toshihiro; Hirata, Akimasa

    2010-08-01

    Contact currents flow from/into a human body when touching an object such as a metal structure with a different electric potential. These currents can stimulate muscle and peripheral nerves. In this context, computational analyses of in situ electric fields caused by the contact current have been performed, while their effectiveness for transient contact currents has not well been investigated. In the present study, using an anatomically based human model, a dispersive finite-difference time-domain model was utilised to computed transient contact current and in situ electric fields from a charged human. Computed in situ electric fields were highly localised in the hand. In order to obtain an insight into the relationship between in situ electric field and electro-stimulation, cell-maximum and 5-mm averaged in situ electric fields were computed and compared with strength-duration curves. The comparison suggests that both measures could be larger than thresholds derived from the strength-duration curves with parameters used in previous studies. PMID:20382974

  5. In situ electric fields causing electro-stimulation from conductor contact of charged human

    International Nuclear Information System (INIS)

    Contact currents flow from/into a human body when touching an object such as a metal structure with a different electric potential. These currents can stimulate muscle and peripheral nerves. In this context, computational analyses of in situ electric fields caused by the contact current have been performed, while their effectiveness for transient contact currents has not well been investigated. In the present study, using an anatomically based human model, a dispersive finite-difference time-domain model was utilised to computed transient contact current and in situ electric fields from a charged human. Computed in situ electric fields were highly localised in the hand. In order to obtain an insight into the relationship between in situ electric field and electro-stimulation, cell-maximum and 5-mm averaged in situ electric fields were computed and compared with strength-duration curves. The comparison suggests that both measures could be larger than thresholds derived from the strength- duration curves with parameters used in previous studies. (authors)

  6. Experimental research on effect of electrode spacing on electro-osmotic dewatering under same voltage gradient%等电势梯度下电极间距对电渗影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    李瑛; 龚晓南

    2012-01-01

    通过室内1:5的模型试验进行了等电势梯度下2m×1 m和1 m×0.5 m两种工程常见矩形布置电极间距下的软黏土电渗性状的研究.利用监测排水量、排水速率、电流、电势、含水率和pH值等指标,对不同电极间距试样的电渗处理效果、能量效率和电极腐蚀等方面进行了分析.结果表明:保持电势梯度不变而减半电极间距能够加快电渗排水,降低土体含水率,减小能量消耗和电极界面电阻,但也会导致土体pH值变化和阳极腐蚀量的增大.此外,采用较小的电极间距可使损失在电极和土接触面上的电势降减小,但损失的电势降占电源电压的比例增大.%A 1:5 scaled model test is conducted in order to find a simple and feasible technical means to improve electro-osmotic efficiency in soft clay foundation. The test program involves two different electrode spacings which are 2m×1m and lm×0.5m. By monitoring drainage, current intensity, voltage, water content and soil pH values, two tests are compared in terms of treatment effect, energy efficiency and electrodes corrosion. The results show that: halving the electrode spacing and keeping the voltage gradient could improve electro-osmotic treatment efficiency effectively including faster drainage rate, more reduction in water content, less energy consumption and less interface resistivity while it would also lead more changes in pH values of soil and more anodes corrosion; moreover, in the condition of halved spacing, smaller voltage drop took place at the soil-electrode interface; but the proportion of the voltage drop to supply voltage is higher.

  7. Thermodynamic study of aqueous solutions of polyelectrolytes of low and medium charge density without added salt by direct measurement of osmotic pressure

    International Nuclear Information System (INIS)

    A special block osmometer has been constructed and applied to a systematic study of poly (vinyl alcohol and vinyl sulphate ester) (PVS) sodium salts in dilute and moderately concentrated salt free aqueous solutions. In order to avoid surely ionic contamination all parts of the equipment that can contact with the polyelectrolyte solutions were made of different kinds of plastics and glass. The pressure range spans from (50 to 1.3 . 105) Pa. The measuring system was found to be appropriate for determination of the molar mass of water soluble polymers, too. Above a certain analytical density of dissociable groups (ADDG) an ion size dependent transition was observed on the reduced osmotic pressure vs. concentration curves. The analysis of the osmotic pressure data has clearly revealed that the dependence of the degree of dissociation on ADDG calculated at zero polyelectrolyte concentration contradicts to 'ion condensation' theory. With increasing polyelectrolyte concentration the degree of dissociation decreased rather steeply but at very low concentrations sharp maximums appeared due either to the change in conformation of these charged macromolecules, or formation of dynamic clusters induced by salting out of neutral parts of the macromolecules by the ionized groups. The applicability of the scaling concept as well as the many possible ways of characterization of non-ideality of polyelectrolyte solutions will be discussed in detail.

  8. Suppression of a Brownian noise in a hole-type sensor due to induced-charge electro-osmosis

    Science.gov (United States)

    Sugioka, Hideyuki

    2016-03-01

    Noise reduction is essential for a single molecular sensor. Thus, we propose a novel noise reduction mechanism using a hydrodynamic force due to induced-charge electro-osmosis (ICEO) in a hole-type sensor and numerically examine the performance. By the boundary element method that considers both a Brownian motion and an ICEO flow of a polarizable particle, we find that the Brownian noise in a current signal is suppressed significantly in a converging channel because of the ICEO flow around the particle in the presence of an electric field. Further, we propose a simple model that explains a numerically obtained threshold voltage of the suppression of the Brownian noise due to ICEO. We believe that our findings contribute greatly to developments of a single molecular sensor.

  9. Charging and discharging tests for obtaining an accurate dynamic electro-thermal model of high power lithium-ion pack system for hybrid and EV applications

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Camacho, Oscar Mauricio Forero; Nørgård, Per Bromand

    2013-01-01

    This paper presents a battery test platform including two Li-ion battery designed for hybrid and EV applications, and charging/discharging tests under different operating conditions carried out for developing an accurate dynamic electro-thermal model of a high power Li-ion battery pack system. The...

  10. Nano-particle size-dependent charging and electro-deposition in dielectric barrier discharges at atmospheric pressure for thin SiO{sub x} film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Jidenko, N [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France); Jimenez, C [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Massines, F [Laboratoire de Genie Electrique de Toulouse, CNRS - Universite Paul Sabatier, 118 route de Narbonne, 31060 Toulouse (France); Borra, J-P [Equipe Decharges Electriques et Environnement du Laboratoire de Physique des Gaz et des Plasmas, UMR 8578 CNRS - Universite Paris-Sud Orsay, F-91405 Supelec, Plateau Moulon, F-91192 Gif Sur Yvette (France)

    2007-07-21

    This paper focuses on charging and electro-deposition of nano-particles produced in a mixture of silane and nitrous oxide diluted in N{sub 2}, by dielectric barrier discharge (DBD) at atmospheric pressure for SiO{sub x} film deposition. Townsend discharge (TD) and filamentary discharge (FD) are compared with and without SiH{sub 4}. Without SiH{sub 4}, particles are produced by filament-surface interaction. Both filament-surface and plasma-silane interactions lead to bimodal particle size distributions from nucleation and agglomeration. With SiH{sub 4}, particle formation and growth imply the same mechanisms in TD and FD. Faster dynamics in FD are related to higher local volume energy density than in TD. From scanning electron microscope images of the film and measurements downstream of the DBD reactor, the diameter of the particle produced is below 50 nm. An analytical model of electro-collection in an ac electric field is used to investigate nano-particle charging. To account for selective electro-deposition leading to particles smaller than 50 nm being included in the layer and to particle size distribution measured downstream of the DBD, the same size-dependent charging and electro-deposition of particle are involved, with different charging dynamics in TD and FD.

  11. Electro-osmosis in kaolinite with pH-dependent surface charge modelling by homogenization

    OpenAIRE

    Sidarta A. Lima; Marcio A. Murad; Christian Moyne; Didier Stemmelen

    2010-01-01

    A new three-scale model to describe the coupling between pH-dependent flows and transient ion transport, including adsorption phenomena in kaolinite clays, is proposed. The kaolinite is characterized by three separate nano/micro and macroscopic length scales. The pore (micro)-scale is characterized by micro-pores saturated by an aqueous solution containing four monovalent ions and charged solid particles surrounded by thin electrical double layers. The movement of the ions is governed by the ...

  12. Electro-osmosis in kaolinite with pH-dependent surface charge modelling by homogenization.

    Science.gov (United States)

    Lima, Sidarta A; Murad, Marcio A; Moyne, Christian; Stemmelen, Didier

    2010-03-01

    A new three-scale model to describe the coupling between pH-dependent flows and transient ion transport, including adsorption phenomena in kaolinite clays, is proposed. The kaolinite is characterized by three separate nano/micro and macroscopic length scales. The pore (micro)-scale is characterized by micro-pores saturated by an aqueous solution containing four monovalent ions and charged solid particles surrounded by thin electrical double layers. The movement of the ions is governed by the Nernst-Planck equations, and the influence of the double layers upon the flow is dictated by the Helmholtz-Smoluchowski slip boundary condition on the tangential velocity. In addition, an adsorption interface condition for the Na+ transport is postulated to capture its retention in the electrical double layer. The two-scale nano/micro model including salt adsorption and slip boundary condition is homogenized to the Darcy scale and leads to the derivation of macroscopic governing equations. One of the notable features of the three-scale model is there construction of the constitutive law of effective partition coefficient that governs the sodium adsorption in the double layer. To illustrate the feasibility of the three-scale model in simulating soil decontamination by electrokinetics, the macroscopic model is discretized by the finite volume method and the desalination of a kaolinite sample by electrokinetics is simulated. PMID:20209253

  13. Charging and discharging tests for obtaining an accurate dynamic electro-thermal model of high power lithium-ion pack system for hybrid and EV applications

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Camacho, Oscar Mauricio Forero; Nørgård, Per Bromand

    2013-01-01

    This paper presents a battery test platform including two Li-ion battery designed for hybrid and EV applications, and charging/discharging tests under different operating conditions carried out for developing an accurate dynamic electro-thermal model of a high power Li-ion battery pack system. The...... aim of the tests has been to study the impact of the battery degradation and to find out the dynamic characteristics of the cells including nonlinear open circuit voltage, series resistance and parallel transient circuit at different charge/discharge currents and cell temperature. An equivalent...

  14. Design of a treatment pilot by electro-coagulation and electro-flotation of high charged liquid effluents; Conception d'un pilote de traitement par electrocoagulation-electroflottation d'effluents liquides fortement charges

    Energy Technology Data Exchange (ETDEWEB)

    Cames, M.C.; Leclerc, J.P.; Valentin, G.; Sanchez-Calvo, L.; Lapicque, F. [Centre National de la Recherche Scientifique (CNRS-ENSIC), Lab. des Sciences du Genie Chimique, 54 - Nancy (France); Rostan, A.; Muller, P. [Centre de Recherche pour l' Environnement, l' Energie et le Dechet, Vivendi Environnement, 78 - Limay (France)

    2001-07-01

    The possibilities of the electro-coagulation and electro-flotation process has been studied on many industrial effluents by cells. The results show that the process efficiency is conditioned by the effluent nature and the dissolved aluminium quantity, what ever the initial rate of Carbon Organic Total (COT). Other parameters as the current density and the circulation speed are not significant. (A.L.B.)

  15. Kerr electro-optic field mapping study of the effect of charge injection on the impulse breakdown strength of transformer oil

    Science.gov (United States)

    Zhang, X.; Zahn, M.

    2013-10-01

    The smart use of charge injection to improve breakdown strength in transformer oil is demonstrated in this paper. Hypothetically, bipolar homo-charge injection with reduced electric field at both electrodes may allow higher voltage operation without insulation failure, since electrical breakdown usually initiates at the electrode-dielectric interfaces. To find experimental evidence, the applicability and limitation of the hypothesis is first analyzed. Impulse breakdown tests and Kerr electro-optic field mapping measurements are then conducted with different combinations of parallel-plate aluminum and brass electrodes stressed by millisecond duration impulse. It is found that the breakdown voltage of brass anode and aluminum cathode is ˜50% higher than that of aluminum anode and brass cathode. This can be explained by charge injection patterns from Kerr measurements under a lower voltage, where aluminum and brass electrodes inject negative and positive charges, respectively. This work provides a feasible approach to investigating the effect of electrode material on breakdown strength.

  16. Electro-osmosis in kaolinite with pH-dependent surface charge modelling by homogenization

    Directory of Open Access Journals (Sweden)

    Sidarta A. Lima

    2010-03-01

    Full Text Available A new three-scale model to describe the coupling between pH-dependent flows and transient ion transport, including adsorption phenomena in kaolinite clays, is proposed. The kaolinite is characterized by three separate nano/micro and macroscopic length scales. The pore (micro-scale is characterized by micro-pores saturated by an aqueous solution containing four monovalent ions and charged solid particles surrounded by thin electrical double layers. The movement of the ions is governed by the Nernst-Planck equations, and the influence of the double layers upon the flow is dictated by the Helmholtz-Smoluchowski slip boundary condition on the tangential velocity. In addition, an adsorption interface condition for the Na+ transportis postulated to capture its retention in the electrical double layer. Thetwo-scalenano/micro model including salt adsorption and slip boundary condition is homogenized to the Darcy scale and leads to the derivation of macroscopic governing equations. One of the notable features of the three-scale model is there construction of the constitutive law of effective partition coefficient that governs the sodium adsorption in the double layer. To illustrate the feasibility of the three-scale model in simulating soil decontamination by electrokinetics, the macroscopic model is discretized by the finite volume method and the desalination of a kaolinite sample by electrokinetics is simulated.Neste artigo propomos um modelo em três escalas para descrever o acoplamento entre o fluxo eletroosmótico e o transporte de íons incluindo fenômenos de adsorção em uma caulinita. A argila é caracterizada por três escalas nano/micro e macroscópica. A escala microscópica é constituída por micro-poros saturados por uma solução aquosa contendo quatro íons monovalentes e partículas sólidas carregadas eletricamente circundadas por uma dupla camada elétrica fina. O movimento dos íons é governado pelas equações de Nernst-Planck e a

  17. Electro-Orientation of Boron-Nitride Nanotubes in Aqueous Solution

    Science.gov (United States)

    Cetindag, Semih; Kim, Sangil; Tiwari, Bishnu; Bhandari, Shiva; Zhang, Dongyan; Yap, Yoke Khin; Shan, Jerry

    2015-11-01

    Boron-nitride nanotubes (BNNTs), which have similar structure to carbon nanotubes but very different electronic properties, are of interest for a variety of applications, including hydrogen storage, water desalination, mechanical reinforcement and improving the thermal conductivity of composites. Many potential applications would benefit from alignment of BNNTs. We demonstrate, for the first time, the ability to align BNNTs, which are insulating at room temperature, with spatially uniform AC fields in aqueous solution. Electro-orientation rates are experimentally found to decline as the frequency of the AC field is increased. The behavior of the cross-over frequency with varying solution conductivity is suggestive of induced-charge-electro-osmotic (ICEO) alignment, despite the extremely low electrical conductivity of BNNTs. We further discuss electro-orientation with DNA-wrapped BNNTs and compare with pristine nanotubes.

  18. Osmotic Dehydration of Fruits

    OpenAIRE

    Guiné, Raquel; Barroca, Maria João

    2009-01-01

    The need for increasing improvements in the quality of food products conducted to an increased interest in osmotic treatment. This technology involves the partial dehydration of a water-rich solid foodstuff, either whole or in pieces, through immersion in an osmotic solution. In fact, osmotic treatment is applied with the goal of modifying the composition of food material through partial water removal and impregnation of solutes, without affecting the structural integrity of products. Three k...

  19. Saltstone Osmotic Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Ralph L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dixon, Kenneth L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRN

    2013-09-23

    Recent research into the moisture retention properties of saltstone suggest that osmotic pressure may play a potentially significant role in contaminant transport (Dixon et al., 2009 and Dixon, 2011). The Savannah River Remediation Closure and Disposal Assessments Group requested the Savannah River National Laboratory (SRNL) to conduct a literature search on osmotic potential as it relates to contaminant transport and to develop a conceptual model of saltstone that incorporates osmotic potential. This report presents the findings of the literature review and presents a conceptual model for saltstone that incorporates osmotic potential. The task was requested through Task Technical Request HLW-SSF-TTR- 2013-0004.

  20. Theory of fluid slip in charged capillary nanopores

    CERN Document Server

    Catalano, J; Biesheuvel, P M

    2016-01-01

    Based on the capillary pore model (space-charge theory) for combined fluid and ion flow through cylindrical nanopores or nanotubes, we derive the continuum equations modified to include wall slip. We focus on the ionic conductance and streaming conductance, cross-coefficients of relevance for electrokinetic energy conversion and electro-osmotic pumping. We combine the theory with a Langmuir-Stern 1-pK charge regulation boundary condition resulting in a non-monotonic dependence of the cross-coefficients on salt concentration.

  1. Saltstone Osmotic Pressure

    International Nuclear Information System (INIS)

    Recent research into the moisture retention properties of saltstone suggest that osmotic pressure may play a potentially significant role in contaminant transport (Dixon et al., 2009 and Dixon, 2011). The Savannah River Remediation Closure and Disposal Assessments Group requested the Savannah River National Laboratory (SRNL) to conduct a literature search on osmotic potential as it relates to contaminant transport and to develop a conceptual model of saltstone that incorporates osmotic potential. This report presents the findings of the literature review and presents a conceptual model for saltstone that incorporates osmotic potential. The task was requested through Task Technical Request HLW-SSF-TTR-2013-0004. Simulated saltstone typically has very low permeability (Dixon et al. 2008) and pore water that contains a large concentration of dissolved salts (Flach and Smith 2013). Pore water in simulated saltstone has a high salt concentration relative to pore water in concrete and groundwater. This contrast in salt concentration can generate high osmotic pressures if simulated saltstone has the properties of a semipermeable membrane. Estimates of osmotic pressure using results from the analysis of pore water collected from simulated saltstone show that an osmotic pressure up to 2790 psig could be generated within the saltstone. Most semi-permeable materials are non-ideal and have an osmotic efficiency 3, KNO3, Na3PO4x12H 2O, and K3PO4 when exposed to a dilute solution. Typically hydraulic head is considered the only driving force for groundwater in groundwater models. If a low permeability material containing a concentrated salt solution is present in the hydrogeologic sequence large osmotic pressures may develop and lead to misinterpretation of groundwater flow and solute transport. The osmotic pressure in the semi-permeable material can significantly impact groundwater flow in the vicinity of the semi-permeable material. One possible outcome is that groundwater

  2. Facet-selective charge carrier transport, deactivation mechanism and stabilization of a Cu2O photo-electro-catalyst.

    Science.gov (United States)

    Li, Yang; Yun, Xiaogang; Chen, Hong; Zhang, Wenqin; Li, Yongdan

    2016-03-14

    A facet-dependent photo-deactivation mechanism of Cu2O was verified and reported, which is caused by the facet-dependent charge carrier transport. During irradiation, the {100} and {110} crystal facets are selectively corroded by the photo-generated holes, while the {111} facets are comparatively stable. PMID:26898270

  3. Shock Electrodeposition in Charged Porous Media

    CERN Document Server

    Han, Ji-Hyung

    2015-01-01

    It is shown that surface conduction in porous media can drastically alter the stability and morphology of electrodeposition at high rates, above the diffusion-limited current. Copper electrodeposits are visualized by scanning electron microscopy and energy dispersive spectroscopy in cellulose nitrate membranes, whose pores are coated with positive or negative charged polymers. Above the limiting current, surface conduction inhibits growth in the positive membrane and produces irregular dendrites, while it enhances growth and suppresses dendrites behind a deionization shock in the negative membrane. The discovery of uniform growth contradicts quasi-steady leaky membrane models, which are in the same universality class as unstable Laplacian growth, and indicates the importance of transient electro-diffusion or electro-osmotic dispersion. Shock electrodeposition could be exploited for high-rate recharging of metal batteries or manufacturing of metal matrix composite coatings.

  4. How does the increment of hetero-cyclic conjugated moieties affect electro-optical and charge transport properties of novel naphtha-difuran derivatives? A computational approach.

    Science.gov (United States)

    Chaudhry, Aijaz Rasool; Ahmed, R; Irfan, Ahmad; Muhammad, Shabbir; Shaari, A; Al-Sehemi, Abdullah G

    2014-12-01

    We have investigated computationally the effects of π-conjugation extension on naphtha[2,1-b:6,5-b'] difuran (DPNDF); where we increase the number of fused NDF (central core) and furan rings in the parent molecule. The molecular structures of all analogues have been optimized at the ground (S0) and first excited (S1) states using density functional theory (DFT) and time-dependent density functional theory (TD-DFT), respectively. Then highest occupied molecular orbitals (HOMOs), the lowest unoccupied molecular orbitals (LUMOs), photophysical properties, adiabatic/vertical electron affinities (EAa)/(EAv), adiabatic/vertical ionization potentials (IPa)/(IPv), and hole/electron reorganization energies λh/λe have been investigated. The effect of NDF and furan rings on structural and electro-optical properties has also been studied. Our calculated reorganization energies of 1a, 1b, and 2c reveal them, materials with balanced hole/electron charge transport, whereas 2a and 2b are good hole-transport materials. By increasing the number of furan rings; the photostability was augmented in 2a, 2b, and 2c. PMID:25503703

  5. Electrokinetic Instability near Charge-Selective Hydrophobic Surfaces

    CERN Document Server

    Shelistov, V S; Ganchenko, G S

    2014-01-01

    The influence of the texture of a hydrophobic surface on the electro-osmotic slip of the second kind and the electrokinetic instability near charge-selective surfaces (permselective membranes, electrodes, or systems of micro- and nanochannels) is investigated theoretically using a simple model based on the Rubinstein-Zaltzman approach. A simple formula is derived to evaluate the decrease in the instability threshold due to hydrophobicity. The study is complemented by numerical investigations both of linear and nonlinear instabilities near a hydrophobic membrane surface. Theory predicts a significant enhancement of the ion flux to the surface and shows a good qualitative agreement with the available experimental data.

  6. Drying brick masonry by electro-osmosis

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Rörig-Dalgaard, Inge

    2006-01-01

    When a fine grained, porous medium is applied an electric DC field, transport of matter occurs, and the transport mechanism in focus of the present study is electro-osmosis, which is transport of water. In laboratory it was shown possible to transport water inside a brick and brick/mortar system ...... a clear movement of water towards the cathode was seen. Thus the basis for utilizing the electro-osmotic effect for drying brick masonry is present, but proper electrodes still needs to be developed....

  7. Asymmetric polymerisation in liquid crystals and resultant electro-chiroptical effect: Structure organising polymerisation and chiral charge carrier ''chiralion''

    International Nuclear Information System (INIS)

    Electrochemical synthesis in liquid crystal (LC) affords conducting polymers having LC molecular order and electro-activity. The polymerisation method can be referred to as structure organising polymerisation (SOP). The optical textures of the polymers thus prepared appear very similar to that of the LC electrolyte solution used for the polymerisation. Especially, polymers prepared in cholesteric LC (chiral LC) having structural chirality show doping-dedoping (redox) driven change in chiroptical activity (controllable circular dichroism and optical rotation), as electro-chiroptical effect. The polymer films exhibit interference colour and electrochemically driven refractive index modulations. The chiroptical activity of the polymer prepared in cholesteric LC comes from axial chirality of the helical structure

  8. Osmotic Pressure in Ionic Microgel Dispersions

    Science.gov (United States)

    Denton, Alan R.; Tang, Qiyun

    2015-03-01

    Microgels are microscopic gel particles, typically 10-1000 nm in size, that are swollen by a solvent. Hollow microgels (microcapsules) can encapsulate cargo, such as dye molecules or drugs, in their solvent-filled cavities. Their sensitive response to environmental conditions (e.g., temperature, pH) and influence on flow properties suit microgels to widespread applications in the chemical, pharmaceutical, food, and consumer care industries. When dispersed in water, polyelectrolyte gels become charged through dissociation of counterions. The electrostatic contribution to the osmotic pressure inside and outside of ionic microgels influences particle swelling and bulk materials properties, including thermodynamic, structural, optical, and rheological properties. Within the primitive and cell models of polyelectrolyte solutions, we derive an exact statistical mechanical formula for the contribution of mobile microions to the osmotic pressure within ionic microgels. Using Poisson-Boltzmann theory, we validate this result by explicitly calculating ion distributions across the surface of an ionic microgel and the electrostatic contribution to the osmotic pressure. Within a coarse-grained one-component model, we further chart the limits of the cell model for salty dispersions. This work was supported by the National Science Foundation under Grant No. DMR-1106331.

  9. A REVIEW ON OSMOTIC DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Harnish Patel

    2012-04-01

    Full Text Available Conventional oral drug delivery systems supply an instantaneous release of drug, which cannot control the release of the drug and effective concentration at the target site. This kind of dosing pattern may result in constantly changing, unpredictable plasma concentrations. Drugs can be delivered in a controlled pattern over a long period of time by the process of osmosis. Osmotic devices are the most promising strategy based systems for controlled drug delivery. They are the most reliable controlled drug delivery systems and could be employed as oral drug delivery systems. Various patents available for osmotic drug delivery system like Rose-Nelson pump, Higuchi leeper pump, Higuchi Theeuwes pump, Elementary Osmotic pump etc. ODDS are useful for poorly soluble drug, for pulsatile drug release, zero order release. Various techniques available for preparation of ODDS include push pull osmotic Pump, osmotic Brusting osmotic pump, liquid oral osmotic system, sandwiched osmotic tablets , delayed delivery osmotic device, monolithic osmotic System and controlled porosity osmotic Pump. Osmotically controlled oral drug delivery systems utilize osmotic pressure for controlled delivery of active agents. These systems can be utilized for systemic as well as targeted delivery of drugs. The release of drugs from osmotic systems is governed by various formulation factors such as solubility and osmotic pressure of the core components, size of the delivery orifice, and nature of the rate-controlling membrane. In this Paper mainly focused on the Osmotic System with example, the basic component of osmotic system and evaluation parameter of the osmotic drug delivery system.

  10. Structure and osmotic pressure of ionic microgel dispersions

    Science.gov (United States)

    Hedrick, Mary M.; Chung, Jun Kyung; Denton, Alan R.

    2015-01-01

    We investigate structural and thermodynamic properties of aqueous dispersions of ionic microgels—soft colloidal gel particles that exhibit unusual phase behavior. Starting from a coarse-grained model of microgel macroions as charged spheres that are permeable to microions, we perform simulations and theoretical calculations using two complementary implementations of Poisson-Boltzmann (PB) theory. Within a one-component model, based on a linear-screening approximation for effective electrostatic pair interactions, we perform molecular dynamics simulations to compute macroion-macroion radial distribution functions, static structure factors, and macroion contributions to the osmotic pressure. For the same model, using a variational approximation for the free energy, we compute both macroion and microion contributions to the osmotic pressure. Within a spherical cell model, which neglects macroion correlations, we solve the nonlinear PB equation to compute microion distributions and osmotic pressures. By comparing the one-component and cell model implementations of PB theory, we demonstrate that the linear-screening approximation is valid for moderately charged microgels. By further comparing cell model predictions with simulation data for osmotic pressure, we chart the cell model's limits in predicting osmotic pressures of salty dispersions.

  11. Structure and osmotic pressure of ionic microgel dispersions

    International Nuclear Information System (INIS)

    We investigate structural and thermodynamic properties of aqueous dispersions of ionic microgels—soft colloidal gel particles that exhibit unusual phase behavior. Starting from a coarse-grained model of microgel macroions as charged spheres that are permeable to microions, we perform simulations and theoretical calculations using two complementary implementations of Poisson-Boltzmann (PB) theory. Within a one-component model, based on a linear-screening approximation for effective electrostatic pair interactions, we perform molecular dynamics simulations to compute macroion-macroion radial distribution functions, static structure factors, and macroion contributions to the osmotic pressure. For the same model, using a variational approximation for the free energy, we compute both macroion and microion contributions to the osmotic pressure. Within a spherical cell model, which neglects macroion correlations, we solve the nonlinear PB equation to compute microion distributions and osmotic pressures. By comparing the one-component and cell model implementations of PB theory, we demonstrate that the linear-screening approximation is valid for moderately charged microgels. By further comparing cell model predictions with simulation data for osmotic pressure, we chart the cell model’s limits in predicting osmotic pressures of salty dispersions

  12. Structure and osmotic pressure of ionic microgel dispersions

    Energy Technology Data Exchange (ETDEWEB)

    Hedrick, Mary M. [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States); Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108-6050 (United States); Chung, Jun Kyung; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

    2015-01-21

    We investigate structural and thermodynamic properties of aqueous dispersions of ionic microgels—soft colloidal gel particles that exhibit unusual phase behavior. Starting from a coarse-grained model of microgel macroions as charged spheres that are permeable to microions, we perform simulations and theoretical calculations using two complementary implementations of Poisson-Boltzmann (PB) theory. Within a one-component model, based on a linear-screening approximation for effective electrostatic pair interactions, we perform molecular dynamics simulations to compute macroion-macroion radial distribution functions, static structure factors, and macroion contributions to the osmotic pressure. For the same model, using a variational approximation for the free energy, we compute both macroion and microion contributions to the osmotic pressure. Within a spherical cell model, which neglects macroion correlations, we solve the nonlinear PB equation to compute microion distributions and osmotic pressures. By comparing the one-component and cell model implementations of PB theory, we demonstrate that the linear-screening approximation is valid for moderately charged microgels. By further comparing cell model predictions with simulation data for osmotic pressure, we chart the cell model’s limits in predicting osmotic pressures of salty dispersions.

  13. Osmotic water transport in aquaporins

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Alsterfjord, Magnus; Beitz, Eric;

    2013-01-01

    molecules give rise to no water transport. Accordingly, the rate of water transport is proportional to the reflection coefficient σ, while the solute permeability, P(S), is proportional to 1 - σ. The model was tested in aquaporins heterologously expressed in Xenopus oocytes. A variety of aquaporin channel...... sizes and geometries were obtained with the two aquaporins AQP1 and AQP9 and mutant versions of these. Osmotic water transport was generated by adding 20 mM of a range of different-sized osmolytes to the outer solution. The osmotic water permeability and the reflection coefficient were measured......Abstract  We test a novel, stochastic model of osmotic water transport in aquaporins. A solute molecule present at the pore mouth can either be reflected or permeate the pore. We assume that only reflected solute molecules induce osmotic transport of water through the pore, while permeating solute...

  14. THEORY OF SIMILARITY OF ELECTRO MEMBRANE SYSTEMS WITH REGARD TO FORCED, GRAVITATIONAL AND ELECTRO CONVECTION

    Directory of Open Access Journals (Sweden)

    Kovalenko A. V.

    2015-01-01

    Full Text Available In the article, we have suggested a general mathematical model of non-stationary and non-isothermal process of a binary electrolyte transfer in dilute solutions in an electro-membrane system (EMS, taking into account the joint action of gravitational convection, forced convection and electro convection in potential dynamic mode. This model is a boundary problem for a system of two-dimensional quasi-linear Navier-Stokes equation and Nernst-Planck-Poisson in partial derivatives equation. We have developed a theory of similarity of the process of heat and mass transfer in electro-membrane systems, specifically, in a desalting channel of electro dialysis apparatus, taking into account joint actions of concentration polarization, space charge, gravity convection, forced convection and electro convection. It is shown that the criterion of electro convection does not directly depend on the initial concentration, and, therefore, electro convection occurs at any initial concentration. At the same time, the criterion of concentration convection linearly dependents on the initial concentration, and, therefore, at high concentrations, concentration convection prevails, while at lower concentrations, the role of gravitational convection begins to fall whereas the role of electro convection increases. The theory of similarity of the process of heat and mass transfer in the desalting channel of electro dialysis apparatus built in this work taking into account the joint action of concentration polarization, space charge, gravity convection, forced convection and electro convection is important for engineering calculations, for scaling the results of experiments in an electro-membrane cell for industrial electro dialysis water desalting apparatus

  15. Determination of colloidal osmotic equation of state by dielectrophoresis

    Science.gov (United States)

    Mazza, Jacob; Huang, Hao; Ou-Yang, H. Daniel

    2015-03-01

    Osmotic equation of state [P(N,T)] describes both the mechanical properties and phase behavior of a colloidal suspension. As an alternative to sedimentation, we propose a new approach to determine P(N,T) by dielectrophoresis (DEP). Using fluorescence confocal microscopy, we obtain particle density profiles in order to determine the DEP force distribution when the particle concentration is low and the inter-particle interactions are negligible. From the known force distribution and Einstein's osmotic equilibrium equation, we can calculate P(N,T) from the particle density profile of interacting, charge-stabilized polystyrene latex particles under different salt concentrations and added neutral polymers. The osmotic equation of state for colloidal suspensions can then be crosschecked by sedimentation equilibrium.

  16. Electro-osmosis in nematic liquid crystals

    Science.gov (United States)

    Tovkach, O. M.; Calderer, M. Carme; Golovaty, Dmitry; Lavrentovich, Oleg; Walkington, Noel J.

    2016-07-01

    We derive a mathematical model of a nematic electrolyte based on a variational formulation of nematodynamics. We verify the model by comparing its predictions to the results of the experiments on the substrate-controlled liquid-crystal-enabled electrokinetics. In the experiments, a nematic liquid crystal confined to a thin planar cell with surface-patterned anchoring conditions exhibits electro-osmotic flows along the "guiding rails" imposed by the spatially varying director. Extending our previous work, we consider a general setup which incorporates dielectric anisotropy of the liquid-crystalline matrix and the full set of nematic viscosities.

  17. Osmotic origin of over pressures in shale formations: impact of osmotic efficiency models

    International Nuclear Information System (INIS)

    The ongoing research on the construction of a possible geological nuclear waste repository in shale formations raises the issue of the electrochemical interactions extensively studied in soil science between pore waters, solutes and clay mineral surfaces. These interactions are related to the negatively charged surfaces of clay platelets which generate the presence of the so-called electric double layer and the occurrence of anion exclusion. This feature suggests that clay formations may have a membrane behaviour. The assumption is supported by extended experimental works on samples in the 1970 and 1980 and more recently by field experiments proving the existence of osmotic behaviour in shales at the field scale i.e. in geological media. The osmotic theory developed in biophysics has been extended to geological situations through the observation that shales can behave as semi-permeable membranes. If the geological membrane is perfect, only water can flow in response to salinity gradients. In most case studies, the semi-permeable layer is not an ideal membrane and some solute transport takes place. Osmotic flow occurs when there is a concentration gradient within the geological medium which causes solute transport dominated by diffusion. The chemical potential drives the fluid flow from the low-concentration zones to the high-concentration ones. In order to account for this chemical potential driving force, an osmotic pressure term π (Pa) has to be added to the hydraulic potential h to describe fluid flow. Darcy law in one dimension is then modified. Osmotic effects are sometimes proposed to explain abnormal pressures in shales. The values of excess pressures that can be obtained by such processes are highly dependent on the a value. This efficiency coefficient is determined from electrochemical or mechanical analyses of the interaction between solutes and clay platelets. Different theories predicting the possible values of these coupling parameters are available

  18. Study on Osmotic Pressure and Liquid-Liquid Equilibria for Micelle, Colloid and Microemulsion Systems by Yukawa Potential

    Institute of Scientific and Technical Information of China (English)

    FU,Dong(付东); LU,Jiu-Fang(陆九芳); WU,Wei(吴畏); Li,Yi-Gui(李以圭)

    2004-01-01

    An equation of state (EOS) was established to study the osmotic pressure and liquid-liquid equilibria for micelle,colloid and microemulsion systems. The Carnahan-Starling equation was used for the hard sphere repulsion. The Yukawa potential was used to describe both the attractive dispersion and the double-layer repulsion. By using the established EOS, the osmotic pressures for charged colloid, uncharged micelle, uncharged and weakly charged microemuslion, the phase equilibria for uncharged micelle and charged colloid systems were studied.

  19. Ultrafiltration of charge-stabilized dispersions at low salinity.

    Science.gov (United States)

    Roa, Rafael; Menne, Daniel; Riest, Jonas; Buzatu, Pompilia; Zholkovskiy, Emiliy K; Dhont, Jan K G; Wessling, Matthias; Nägele, Gerhard

    2016-05-18

    We present a comprehensive study of cross-flow ultrafiltration (UF) of charge-stabilized suspensions, under low-salinity conditions of electrostatically strongly repelling colloidal particles. The axially varying permeate flux, near-membrane concentration-polarization (CP) layer and osmotic pressure profiles are calculated using a macroscopic diffusion-advection boundary layer method, and are compared with filtration experiments on aqueous suspensions of charge-stabilized silica particles. The theoretical description based on the one-component macroion fluid model (OCM) accounts for the strong influence of surface-released counterions on the renormalized colloid charge and suspension osmotic compressibility, and for the influence of the colloidal hydrodynamic interactions and electric double layer repulsion on the concentration-dependent suspension viscosity η, and collective diffusion coefficient Dc. A strong electro-hydrodynamic enhancement of Dc and η, and likewise of the osmotic pressure, is predicted theoretically, as compared with their values for a hard-sphere suspension. We also point to the failure of generalized Stokes-Einstein relations describing reciprocal relations between Dc and η. According to our filtration model, Dc is of dominant influence, giving rise to an only weakly developed CP layer having practically no effect on the permeate flux. This prediction is quantitatively confirmed by our UF measurements of the permeate flux using an aqueous suspension of charged silica spheres as the feed system. The experimentally detected fouling for the largest considered transmembrane pressure values is shown not to be due to filter cake formation by crystallization or vitrification. PMID:27113088

  20. Electro-Deposition Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The electro-deposition laboratory can electro-deposit various coatings onto small test samples and bench level prototypes. This facility provides the foundation for...

  1. Role of Osmotic Adjustment in Plant Productivity

    Energy Technology Data Exchange (ETDEWEB)

    Gebre, G.M.

    2001-01-11

    Successful implementation of short rotation woody crops requires that the selected species and clones be productive, drought tolerant, and pest resistant. Since water is one of the major limiting factors in poplar (Populus sp.) growth, there is little debate for the need of drought tolerant clones, except on the wettest of sites (e.g., lower Columbia River delta). Whether drought tolerance is compatible with productivity remains a debatable issue. Among the many mechanisms of drought tolerance, dehydration postponement involves the maintenance of high leaf water potential due to, for example, an adequate root system. This trait is compatible with productivity, but requires available soil moisture. When the plant leaf water potential and soil water content decline, the plant must be able to survive drought through dehydration tolerance mechanisms, such as low osmotic potential or osmotic adjustment. Osmotic adjustment and low osmotic potential are considered compatible with growth and yield because they aid in the maintenance of leaf turgor. However, it has been shown that turgor alone does not regulate cell expansion or stomatal conductance and, therefore, the role of osmotic adjustment is debated. Despite this finding, osmotic adjustment has been correlated with grain yield in agronomic crop species, and gene markers responsible for osmotic adjustment are being investigated to improve drought tolerance in productive progenies. Although osmotic adjustment and low osmotic potentials have been investigated in several forest tree species, few studies have investigated the relationship between osmotic adjustment and growth. Most of these studies have been limited to greenhouse or container-grown plants. Osmotic adjustment and rapid growth have been specifically associated in Populus and black spruce (Picea mariuna (Mill.) B.S.P.) progenies. We tested whether these relationships held under field conditions using several poplar clones. In a study of two hybrid poplar

  2. Efficiency of osmotic pipe flows

    DEFF Research Database (Denmark)

    Haaning, Louise Sejling; Jensen, Kaare Hartvig; Helix Nielsen, Claus;

    2013-01-01

    We present experiments and theory for flows of sugar or salt solutions in cylindrical tubes with semipermeable walls (hollow fiber membranes) immersed in water, quantifying the strength of the osmotic driving force in relation to the dimensionless parameters that specify the system. The pumping e...

  3. Osmotic Effects in Sludge Dewatering

    DEFF Research Database (Denmark)

    Keiding, Kristian; Rasmussen, Michael R.

    2003-01-01

    A model of filtration dewatering is presented. The model is based on the d’Arcy flow equation in which the resistance to filtration is described by the Corzeny–Carman equation and the driving force is the difference between the external pressure and the osmotic pressure of the filter cake. It has...

  4. LO-TO splittings, effective charges and interactions in electro-optic meta-nitroaniline crystal as studied by polarized IR reflection and transmission spectra

    Science.gov (United States)

    Szostak, M. M.; Le Calvé, N.; Romain, F.; Pasquier, B.

    1994-10-01

    The polarized IR reflection spectra of the meta-nitroaniline ( m-NA) single crystal along the a, b and c crystallographic axes as well as the b and c polarized transmission spectra have been measured in the 100-400 cm -1 region. The LO-TO splitting values have been calculated from the reflection spectra by fitting them with the four parameter dielectric function. The dipole moment derivatives, relevant to dynamic effective charges, of the vibrations have also been calculated and used to check the applicability of the oriented gas model (OGM) to reflection spectra. The discrepancies from the OGM have been discussed in terms of vibronic couplings, weak hydrogen bondings (HB) and intramolecular charge transfer.

  5. The Role of the Tight Junction in Paracellular Fluid Transport across Corneal Endothelium. Electro-osmosis as a Driving Force.

    Science.gov (United States)

    Fischbarg, J; Diecke, F P J; Iserovich, P; Rubashkin, A

    2006-03-01

    The mechanism of epithelial fluid transport is controversial and remains unsolved. Experimental difficulties pose obstacles for work on a complex phenomenon in delicate tissues. However, the corneal endothelium is a relatively simple system to which powerful experimental tools can be applied. In recent years our laboratory has developed experimental evidence and theoretical insights that illuminate the mechanism of fluid transport across this leaky epithelium. Our evidence points to fluid being transported via the paracellular route by a mechanism requiring junctional integrity, which we attribute to electro-osmotic coupling at the junctions. Fluid movements can be produced by electrical currents. The direction of the movement can be reversed by current reversal or by changing junctional electrical charges by polylysine. Aquaporin 1 (AQP1) is the only AQP present in these cells, and its deletion in AQP1 null mice significantly affects cell osmotic permeability but not fluid transport, which militates against the presence of sizable water movements across the cell. By contrast, AQP1 null mice cells have reduced regulatory volume decrease (only 60% of control), which suggests a possible involvement of AQP1 in either the function or the expression of volume-sensitive membrane channels/transporters. A mathematical model of corneal endothelium predicts experimental results only when based on paracellular electro-osmosis, and not when transcellular local osmosis is assumed instead. Our experimental findings in corneal endothelium have allowed us to develop a novel paradigm for this preparation that includes: (1) paracellular fluid flow; (2) a crucial role for the junctions; (3) hypotonicity of the primary secretion; (4) an AQP role in regulation and not as a significant water pathway. These elements are remarkably similar to those proposed by the Hill laboratory for leaky epithelia. PMID:16868674

  6. Extra pontine osmotic demyelination syndrome

    OpenAIRE

    Zunga, Pervaiz M.; Farooq, Omar; Dar, Mohd I.; Dar, Ishrat H; Rashid, Samia; Rather, Abdul Q.; Basu, Javid A; Ashraf, Mohammed; Jahangeer A. Bhat

    2015-01-01

    The osmotic demyelination syndrome (ODS) has been identified as a complication of the rapid correction of hyponatremia for decades. However, in recent years, a variety of other medical conditions have been associated with the development of ODS, independent of changes in serum sodium which cause a rapid changes in osmolality of the interstitial (extracellular) compartment of the brain leading to dehydration of energy-depleted cells with subsequent axonal damage that occurs in characteristic a...

  7. Towards Relativistic Atomic Physics. I. The Rest-Frame Instant Form of Dynamics and a Canonical Transformation for a System of Charged Particles plus the Electro-Magnetic Field

    CERN Document Server

    Alba, David; Lusanna, Luca

    2008-01-01

    A complete exposition of the rest-frame instant form of dynamics for arbitrary isolated systems (particles, fields, strings, fluids)admitting a Lagrangian description is given. The starting point is the parametrized Minkowski theory describing the system in arbitrary admissible non-inertial frames in Minkowski space-time, which allows one to define the energy-momentum tensor of the system and to show the independence of the description from the clock synchronization convention and from the choice of the 3-coordinates. In the inertial rest frame the isolated system is seen as a decoupled non-covariant canonical external center of mass carrying a pole-dipole structure (the invariant mass $M$ and the rest spin ${\\vec {\\bar S}}$ of the system) and an external realization of the Poincare' group. Then an isolated system of positive-energy charged scalar articles plus an arbitrary electro-magnetic field in the radiation gauge is investigated as a classical background for defining relativistic atomic physics. The ele...

  8. Auxin response under osmotic stress.

    Science.gov (United States)

    Naser, Victoria; Shani, Eilon

    2016-08-01

    The phytohormone auxin (indole-3-acetic acid, IAA) is a small organic molecule that coordinates many of the key processes in plant development and adaptive growth. Plants regulate the auxin response pathways at multiple levels including biosynthesis, metabolism, transport and perception. One of the most striking aspects of plant plasticity is the modulation of development in response to changing growth environments. In this review, we explore recent findings correlating auxin response-dependent growth and development with osmotic stresses. Studies of water deficit, dehydration, salt, and other osmotic stresses point towards direct and indirect molecular perturbations in the auxin pathway. Osmotic stress stimuli modulate auxin responses by affecting auxin biosynthesis (YUC, TAA1), transport (PIN), perception (TIR/AFB, Aux/IAA), and inactivation/conjugation (GH3, miR167, IAR3) to coordinate growth and patterning. In turn, stress-modulated auxin gradients drive physiological and developmental mechanisms such as stomata aperture, aquaporin and lateral root positioning. We conclude by arguing that auxin-mediated growth inhibition under abiotic stress conditions is one of the developmental and physiological strategies to acclimate to the changing environment. PMID:27052306

  9. Casein Micelle Dispersions under Osmotic Stress

    OpenAIRE

    Bouchoux, Antoine; Cayemitte, Pierre-Emerson; Jardin, Julien; Gésan-Guiziou, Geneviève; Cabane, Bernard

    2009-01-01

    Casein micelles dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis. This technique measured an equation of state of the dispersions over a wide range of pressures and concentrations and at different ionic strengths. Three regimes were found. i), A dilute regime in which the osmotic pressure is proportional to the casein concentration. In this regime, the casein micelles are well separated and rarely interact, whereas the osmotic press...

  10. Application and Research of Combination of Electro-osmotic Method and Vacuum-overlying Water Preloading Method for Strengthening Dredger Fill%电渗复合真空覆水预压法加固吹填土地基的应用研究

    Institute of Scientific and Technical Information of China (English)

    沈扬; 陶明安; 刘志浩; 刘汉龙

    2012-01-01

    吹填土渗透系数小,结合水含量高,常规排水固结法只能排除地基土中的自由水,且真空传递效率低.而电渗法已经被证明可以有效排除土体中的结合水.故提出电渗复合真空覆水预压加固吹填土的方法,并结合温州某吹填土地基处理工程,对电渗复合真空覆水预压技术进行了现场试验研究.结果表明,电渗法能够有效降低地下水位,并对土体后期强度增长的贡献明显;电渗复合真空覆水预压法加固效果好于真空覆水预压法,在地基土的沉降速率上有显著优势,达到相同地基处理效果,施工工期更短,为该技术的推广应用提供借鉴和指导.%Dredger fill has low permeability and high contant of bound water. Conventional vacuum preloading method can only exclude free water from the ground, and the efficiency is low to the such kind of soil. While electro-osmosis method has proved to be effective in the exclusion of bound water. So the combination of the electro-osmosis method and the vacuum-overlying water preloading method, was proposed to improve dredger fill ground. And the correlated in-suit tests were performed with the dredger fill ground treatment project in Wenzhou. The results showed that electro-osmosis method could effectively lower the groundwater level and contributed significantly to the growth of soil' s late strength. The combination method with electro-osmosis and vacuum preloading has achieved better effects than the vacuum preloading method alone, especially in the shortening of the construction period by increasing of the ground settlement rate.

  11. [Effect of osmotic pressure on nitrification].

    Science.gov (United States)

    Zheng, Ping; Wu, Ming-Sheng

    2006-01-01

    The effect of osmotic pressure on nitrification was investigated in the internal-loop air-lift nitrifying reactor. When influent ammonia concentration is kept at 420mg x L(-1) and influent osmotic pressure is increased from 4.3 to 18.8 x 10(5) Pa, the ammonia conversion of the nitrifying bioreactor is maintained between 93% and 100%. After influent osmotic pressure is further increased to 19.2 x 10(5)Pa, the ammonia conversion goes down to 69.2%. The influence of osmotic pressure on nitrification takes place without any alarm and the critical osmotic pressure is between 18.8 x 10(5) and 19.2 x 10(5) Pa. During osmotic stress, the nitrifying bacterial populations in the activated sludge become simplified, the cell size becomes smaller, the inner membrane becomes less and some unknown inclusion particles are formed. The cell structure is restored as soon as the osmotic pressure is removed. Addition of potassium is able to relieve the effect of osmotic pressure on nitrification. The nitrifying activity of the activated sludge is stimulated by the osmotic stress, and the specific ammonia conversion is increased from 0.083 kg x kg(-1) x d(-1) to 0.509 kg x kg(-1) x d(-1) and 2.569 kg x kg(-1) x d(-1), respectively. PMID:16572857

  12. Harnessing electro driven separation technique for the separation of selected agrochemicals

    International Nuclear Information System (INIS)

    Electro driven separation techniques offer a different approach to the analysis of complex mixtures than do traditional pressure-driven chromatographic system; it may rely on electrophoresis, the transport of charged species through a medium by an applied field or may rely on electro driven mobile phase to provide a true chromatographic separation. In the current work the potential of an electro driven separation technique viz. Micellar electrokinetic chromatography (MEKC), is harnessed for the separation of selected agrochemicals (organophosphorus pesticides, OPPs) widely used in the agriculture sector in Malaysia. The current study compares the use of MEKC in normal mode (NM) and reverse mode (RM) for the separation of the selected OPPS. This study also highlights the difference in separations produced by performing separations in normal mode-MEKC (NM-MEKC) and reverse mode-MEKC (RM-MEKC) for the selected OPPs. In RM-MEKC, separation is conducted at acidic pH (pH 2.5 in the current work) where the electro osmotic flow (EOF) is weak whereas in NM-MEKC, the separation is carried out under basic pH (9.3 in this work) where the EOF is strong. A reverse migration order of the OPPs was observed under RM-MEKC. Separation under NM-MEKC was found to be superior to those of RM- MEKC. A comparison is also made between separations performed under sweeping-NM-MEKC and sweeping-RM-MEKC. In sweeping, the OPPs are prepared in the same background solution (BGS) minus the micelles and is adjusted to the same conductivity as the BGS. The study showed that NM-MEKC is more sensitive than RM-MEKC but sweeping-RM-MEKC is superior to sweeping-NM-MEKC. However, sweeping-RM-MEKC only separates two of the OPPs in a single run whereas sweeping-NM-MEKC separates four OPPs in a single run. The better choice of separation mode would be sweeping-NM- MEKC for more OPPs separation in a single run. (author)

  13. Electro-Optical Nanotraps for Neutral Atoms

    OpenAIRE

    Murphy, Brian; Hau, Lene Vestergaard

    2008-01-01

    We propose a new class of nanoscale electro-optical traps for neutral atoms. A prototype is the toroidal trap created by a suspended, charged carbon nanotube decorated with a silver nanosphere dimer. An illuminating laser field, blue detuned from an atomic resonance frequency, is strongly focused by plasmons induced in the dimer and generates both a repulsive potential barrier near the nanostructure surface and a large viscous damping force that facilitates trap loading. Atoms with velocities...

  14. Osmotic water transport through carbon nanotube membranes

    OpenAIRE

    Kalra, Amrit; Garde, Shekhar; Hummer, Gerhard

    2003-01-01

    We use molecular dynamics simulations to study osmotically driven transport of water molecules through hexagonally packed carbon nanotube membranes. Our simulation setup comprises two such semipermeable membranes separating compartments of pure water and salt solution. The osmotic force drives water flow from the pure-water to the salt-solution compartment. Monitoring the flow at molecular resolution reveals several distinct features of nanoscale flows. In particular, thermal fluctuatio...

  15. Osmotic dehydration of fish: principal component analysis

    OpenAIRE

    Lončar Biljana Lj.; Pezo Lato L.; Lević Ljubinko B.; Filipović Vladimir S.; Nićetin Milica R.; Knežević Violeta M.; Kuljanin Tatjana A.

    2014-01-01

    Osmotic treatment of the fish Carassius gibelio was studied in two osmotic solutions: ternary aqueous solution - S1, and sugar beet molasses - S2, at three solution temperatures of 10, 20 and 30oC, at atmospheric pressure. The aim was to examine the influence of type and concentration of the used hypertonic agent, temperature and immersion time on the water loss, solid gain, dry mater content, aw and content of minerals (Na, K, Ca and Mg). S2 solution has p...

  16. The chronicle of the electro-magnetostatic

    International Nuclear Information System (INIS)

    The Chronicle of the electro-magnetostatic is shown, since the first observation made by Tales de Mileto, in the VI centry B.C., about the magnetic and electric phenomenons, up to the mathematical learning of the electrical circuits, made by Kirchhoff, almost in the first half of the XIX century. In run away of this chronicle, the experimental laws involving the behavior of the electrical charge, in the insulators and in the conductors, are presented as well as the piezo and piro-electrical and chemical effects the electrical charge incite in some substances. (Author)

  17. Extra pontine osmotic demyelination syndrome.

    Science.gov (United States)

    Zunga, Pervaiz M; Farooq, Omar; Dar, Mohd I; Dar, Ishrat H; Rashid, Samia; Rather, Abdul Q; Basu, Javid A; Ashraf, Mohammed; Bhat, Jahangeer A

    2015-01-01

    The osmotic demyelination syndrome (ODS) has been identified as a complication of the rapid correction of hyponatremia for decades. However, in recent years, a variety of other medical conditions have been associated with the development of ODS, independent of changes in serum sodium which cause a rapid changes in osmolality of the interstitial (extracellular) compartment of the brain leading to dehydration of energy-depleted cells with subsequent axonal damage that occurs in characteristic areas. Slow correction of the serum sodium concentration and additional administration of corticosteroids seems to be a major prevention step in ODS patients. In the current report we aimed to share a rare case which we observed in our hospital. A 65 year old female admitted as altered sensorium with history of vomiting, diarrhea was managed with intravenous fluids for 2 days at a peripheral health centre. Patient was referred to our centre with encephalopathy, evaluated and found to have hyponatremia and hypokalemia rest of biochemical parameters and septic profile were normal. Patient's electrolyte disturbances were managed as per guidelines but encephalopathy persisted. Supportive treatment was continued and patient was discharged after 2 wks of stay in hospital after gaining full sensorium and neurological functions. PMID:26124552

  18. Determination of colloidal particle surface charge from dielectrophoresis

    Science.gov (United States)

    Chavez, Marko; Nuansri, Rittirong; Mazza, Jacob; Ou-Yang, H. Daniel

    2015-03-01

    Electrophoresis (EP) is used to determine colloidal particle surface charge. However, when the Debye length is comparable to or larger than the particle size, electrophoresis cannot be reliably used to determine the surface charge due to counter ion retardation flow. Alexander et al. developed a theory relating colloidal osmotic pressure and particle surface charge. We use dielectrophoresis (DEP) to obtain a potential landscape based on the number density distribution of the particles in a non-uniform AC electric field. We determine the osmotic pressure from the DEP force and density profiles using Einstein's osmotic equilibrium equation. Surface charge obtained by DEP (thermodynamics) will be compared to that obtained by EP (electrokinetics).

  19. Practical electro technology

    International Nuclear Information System (INIS)

    This book deals with practical electro technology with seven chapters, which explain basics of electricity and electron, circuit theory like a direct current circuit and alternating current circuit, DC machine such as principle and structure, theory, kinds and property of DC machine generator and DC motor, operation, loss and efficiency of DC machine, synchronous machine like induced electro motive force and property, tannoform such as structure, principle and kinds, induction motor like theory, operation and control of speed and electric application like a measuring instrument and power system in the ship.

  20. Microfluidic pumping, routing and metering by contactless metal-based electro-osmosis.

    Science.gov (United States)

    Fu, Xiaotong; Mavrogiannis, Nicholas; Doria, Steven; Gagnon, Zachary

    2015-09-01

    Over the past decade, many microfluidic platforms for fluid processing have been developed in order to perform on-chip fluidic manipulations. Many of these methods, however, require expensive and bulky external supporting equipment, which are not typically applicable for microsystems requiring portability. We have developed a new type of portable contactless metal electro-osmotic micropump capable of on-chip fluid pumping, routing and metering. The pump operates using two pairs of gallium metal electrodes, which are activated using an external voltage source, and separated from a main flow channel by a thin micron-scale PDMS membrane. The thin contactless membrane allows for field penetration and electro-osmotic (EO) flow within the microchannel, but eliminates electrode damage and sample contamination commonly associated with traditional DC electro-osmotic pumps that utilize electrodes in direct contact with the working fluid. The maximum flow rates and pressures generated by the pump using DI water as a working buffer are 10 nL min(-1) and 30 Pa, respectively. With our current design, the maximum operational conductivity where fluid flow is observed is 0.1 mS cm(-1). Due to the small size and simple fabrication procedure, multiple micropump units can be integrated into a single microfluidic device for automated on-chip routing and sample metering applications. We experimentally demonstrated the ability to quantify micropump electro-osmotic flowrate and pressure as a function of applied voltage, and developed a mathematical model capable of predicting the performance of a contactless micropump for a given external load and internal hydrodynamic microchannel resistance. Finally, we showed that by activating specific pumps within a microchannel network, our micropumps are capable of routing microchannel fluid flow and generating plugs of solute. PMID:26053965

  1. Electro Hydraulic Hitch Control

    DEFF Research Database (Denmark)

    Hansen, M. R.; Andersen, T. O.; Nielsen, B.;

    2003-01-01

    This paper present and discusses R&D results on electro hydraulic hitch control for off-road vehicle, in particular active damping of oscillation occuring on tractors. The research deals with analysis and control of the oscillations occuring on tractors which are design without any susspection...

  2. Hydrodynamics and electro-osmosis in clay by molecular simulation: comparison of two force-fields

    International Nuclear Information System (INIS)

    Document available in abstract form only. Full text of publication follows: Understanding mass transfer through clay pores is necessary in many contexts, such as groundwater hydrology, gas reservoir engineering, and carbon dioxide sequestration or geological disposal of radioactive waste. The up-scaling from the pore-scale flow, usually described by the Navier-Stokes equation, to the macroscopic one, satisfying Darcy's law, can be obtained using the mathematical tools of homogenization. However the validity of continuous solvent equation as the Navier-Stokes one can be questioned, especially in nano-pores where the diffusion and hydrodynamic flow can be seriously influenced by the fluid interaction with the surface. Non-equilibrium molecular dynamics (NEMD) simulation is used to investigate the validity of continuous hydrodynamics of water in nano-pores of a charged clay and an uncharged one (montmorillonite and pyrophyllite respectively). The characteristics of hydrodynamic and electro-osmotic flows obtained with two different clay force-fields (SSFF and clayFF) are compared: in both cases, the Navier-Stokes equation can be used to predict simulated flow, as long as slip boundary conditions are taken into account at the solid/liquid interface. However slippy/sticky conditions depend strongly on the force-field and the charge of the clay, leading to contradictory conclusions. Considering previous works showing a better agreement for water diffusion and hydrophilic/hydrophobic clay surface characteristics between clayFF and experiment, this force-field, if not perfect, should be preferred in future works. (authors)

  3. Collective osmotic shock in ordered materials.

    Science.gov (United States)

    Zavala-Rivera, Paul; Channon, Kevin; Nguyen, Vincent; Sivaniah, Easan; Kabra, Dinesh; Friend, Richard H; Nataraj, S K; Al-Muhtaseb, Shaheen A; Hexemer, Alexander; Calvo, Mauricio E; Miguez, Hernan

    2012-01-01

    Osmotic shock in a vesicle or cell is the stress build-up and subsequent rupture of the phospholipid membrane that occurs when a relatively high concentration of salt is unable to cross the membrane and instead an inflow of water alleviates the salt concentration gradient. This is a well-known failure mechanism for cells and vesicles (for example, hypotonic shock) and metal alloys (for example, hydrogen embrittlement). We propose the concept of collective osmotic shock, whereby a coordinated explosive fracture resulting from multiplexing the singular effects of osmotic shock at discrete sites within an ordered material results in regular bicontinuous structures. The concept is demonstrated here using self-assembled block copolymer micelles, yet it is applicable to organized heterogeneous materials where a minority component can be selectively degraded and solvated whilst ensconced in a matrix capable of plastic deformation. We discuss the application of these self-supported, perforated multilayer materials in photonics, nanofiltration and optoelectronics. PMID:22120413

  4. Inverse osmotic process for radioactive laundry waste

    International Nuclear Information System (INIS)

    Purpose: To effectively recover the processing amount reduced in a continuous treatment. Method: Laundry waste containing radioactive substances discharged from a nuclear power plant is processed in an inverse osmotic process while adding starch digesting enzymes such as amylase and takadiastase, as well as soft spherical bodies such as sponge balls of a particle diameter capable of flowing in the flow of the liquid wastes along the inverse osmotic membrane pipe and having such a softness and roundness as not to damage the inverse osmotic membrane. This process can remove the floating materials such as thread dusts or hairs deposited on the membrane surface by the action of the soft elastic balls and remove paste or the like through decomposition by the digesting enzymes. Consequently, effective recovery can be attained for the reduced processing amount. (Furukawa, Y.)

  5. Dependence of osmotic pressure on solution properties

    International Nuclear Information System (INIS)

    Hydrostatic pressure, temperature, salt concentration, and the chemical composition of the salt are parameters affecting solution properties. Pressure and temperature have little effect on osmosis, but osmotic pressure variations due to type of dissolved salt may be significant, especially at high concentrations. For a given salt solution, concentration variations cause large differences in osmotic pressure. A representative difference in concentration across a clay layer in a relatively shallow groundwater system might be 100 to 1,000 ppm. When expressed as ppm NaCl, this difference could cause a head difference of 0.8 to 8 meters of water if one of the rock bodies were closed to fluid escape

  6. Osmotic dehydration of fish: principal component analysis

    Directory of Open Access Journals (Sweden)

    Lončar Biljana Lj.

    2014-01-01

    Full Text Available Osmotic treatment of the fish Carassius gibelio was studied in two osmotic solutions: ternary aqueous solution - S1, and sugar beet molasses - S2, at three solution temperatures of 10, 20 and 30oC, at atmospheric pressure. The aim was to examine the influence of type and concentration of the used hypertonic agent, temperature and immersion time on the water loss, solid gain, dry mater content, aw and content of minerals (Na, K, Ca and Mg. S2 solution has proven to be the best option according to all output variables.[ Projekat Ministarstva nauke Republike Srbije, br. TR 31055

  7. Electro Hydraulic Hitch Control

    DEFF Research Database (Denmark)

    Hansen, M. R.; Andersen, T. O.; Nielsen, B.;

    2003-01-01

    This paper present and discusses R&D results on electro hydraulic hitch control for off-road vehicle, in particular active damping of oscillation occuring on tractors. The research deals with analysis and control of the oscillations occuring on tractors which are design without any susspection...... for a parameter research study with emphasis on the requirements to the hitch control by use of hydraulic pressure compensated proportional control valve....

  8. Electric-field Induced Microdynamics of Charged Rods

    Directory of Open Access Journals (Sweden)

    Kyongok eKang

    2014-12-01

    Full Text Available Electric-field induced phase/state transitions are observed in AC electric fields with small amplitudes and low frequencies in suspensions of charged fibrous viruses (fd, which are model systems for highly charged rod-like colloids. Texture- and particle-dynamics in these field-induced states, and on crossing transition lines, are explored by image time-correlation and dynamic light scattering, respectively. At relatively low frequencies, starting from a system within the isotropic-nematic coexistence region, a transition from a nematic to a chiral nematic is observed, as well as a dynamical state where nematic domains melt and reform. These transitions are preliminary due to field-induced dissociation/association of condensed ions. At higher frequencies a uniform state is formed that is stabilized by hydrodynamic interactions through field-induced electro-osmotic flow where the rods align along the field direction. There is a point in the field-amplitude versus frequency plane where various transition lines meet. This point can be identified as a non-equilibrium critical point, in the sense that a length scale and a time scale diverge on approach of that point. The microscopic dynamics exhibits discontinuities on crossing transition lines that were identified independently by means of image and signal correlation spectroscopy.

  9. Electro-chemo-hydro-mechanical coupling in clayey media

    International Nuclear Information System (INIS)

    The aim of this study is to understand coupled phenomena that occur in swelling porous materials like clays. Electro-chemo-hydro-mechanical contributions are taken into account to analyze transfers in such minerals. In a first part, a general discussion is proposed to introduce mineralogical and physico- chemical considerations of clayey media. An important objective of this chapter is to show the crucial role of the microstructure. In a second part is presented an imbibition test in a MX80 bentonite powder. The hydraulic diffusivity versus water content curve's decrease is explained thanks to a double porosity model that shows the progressive collapse of meso-pores due to swelling effects at the micro-scale. Thus a multi-scale analysis is necessary to well describe clayey media behaviour. The third chapter exposes such a multi-scale modelling (periodic homogenization). It is based on the double-layer theory and introduces an innovative concept of virtual electrolyte solution. First numerical results are given in a simple geometry (parallel platelets). In the next part are proposed numerical simulations of two kinds: response of the system to a chemical gradient and simulation of electro-osmosis. The end of this chapter puts into relief the necessity to integrate pH effects in the model. In the last part, chemical surface exchanges are incorporated in the modelling to understand pH and ionic force roles in electro-osmotic process. (author)

  10. Strange Attractors Characterizing the Osmotic Instability

    CERN Document Server

    Tzenov, Stephan I

    2014-01-01

    In the present paper a simple dynamical model for computing the osmotically driven fluid flow in a variety of complex, non equilibrium situations is derived from first principles. Using the Oberbeck-Boussinesq approximation, the basic equations describing the process of forward osmosis have been obtained. It has been shown that these equations are very similar to the ones used to model the free Rayleigh-Benard convection. The difference is that while in the case of thermal convection the volume expansion is driven by the coefficient of thermal expansion, the key role for the osmotic instability is played by the coefficient of isothermal compressibility. In addition, it has been shown that the osmotic process represents a propagation of standing waves with time-dependent amplitudes and phase velocity, which equals the current velocity of the solvent passing through the semi-permeable membrane. The evolution of the amplitudes of the osmotic waves is exactly following the dynamics of a strange attractor of Loren...

  11. Magnetically Guided Propulsion of Osmotic Motors

    Science.gov (United States)

    Vidal, Glenn; Rinaldi, Carlos; Córdova-Figueroa, Ubaldo

    2010-11-01

    Propulsion of artificial nano- and micro-scale objects induced by chemical reactions is one of the most exciting challenges in colloidal physics. Recent experiments have shown that directed motion of catalytic motors is hindered by their rotary Brownian motion, preventing its potential to be fully realized. The present work investigates the magnetically guided propulsion of a colloidal particle--the osmotic motor-- immersed in a dispersion of colloidal `bath' particles subject to an unidirectional magnetic field using Brownian dynamics simulation. The osmotic motor is propelled by a chemical reaction that consumes bath particles over a portion of its surface. The non-equilibrium microstructure of bath particles induced by the surface reaction creates an `osmotic pressure' imbalance on the motor's surface causing it to move to regions of lower bath particle concentration. The strength of the magnetic field is controlled by the Langevin parameter, which physically measures the relative importance of magnetic to Brownian torques, and dictates the directionality of the osmotic motor. The translational self-diffusivity is measured for different reaction speeds, particle sizes, bath particle concentrations, and magnetic dipole orientations. Finally, a theory to determine the long-time self-diffusivity and time-averaged particle velocity is developed and compared to the simulation results.

  12. Electro-diffusion in a plasma with two ion species

    CERN Document Server

    Kagan, Grigory

    2012-01-01

    Electric field is a thermodynamic force that can drive collisional inter-ion-species transport in a multicomponent plasma. In an inertial confinement fusion (ICF) capsule, such transport causes fuel ion separation even with a target initially prepared to have equal number densities for the two fuel ion species. Unlike the baro-diffusion driven by ion pressure gradient and the thermo-diffusion driven by ion and electron temperature gradients, electro-diffusion has a critical dependence on the charge-to-mass ratio of the ion species. Specifically, it is shown here that electro-diffusion vanishes if the ion species have the same charge-to-mass ratio. An explicit expression for the electro-diffusion ratio is obtained and used to investigate the relative importance of electro- and baro-diffusion mechanisms. In particular, it is found that electro-diffusion reinforces baro-diffusion in the deuterium and tritium mix, but tends to cancel it in the deuterium and helium-3 mix.

  13. Electro-chemo-hydro-mechanical coupling in clayey media; Couplage electro-chimio-hydro-mecaniques dans les milieux argileux

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, Th

    2004-12-15

    The aim of this study is to understand coupled phenomena that occur in swelling porous materials like clays. Electro-chemo-hydro-mechanical contributions are taken into account to analyze transfers in such minerals. In a first part, a general discussion is proposed to introduce mineralogical and physico- chemical considerations of clayey media. An important objective of this chapter is to show the crucial role of the microstructure. In a second part is presented an imbibition test in a MX80 bentonite powder. The hydraulic diffusivity versus water content curve's decrease is explained thanks to a double porosity model that shows the progressive collapse of meso-pores due to swelling effects at the micro-scale. Thus a multi-scale analysis is necessary to well describe clayey media behaviour. The third chapter exposes such a multi-scale modelling (periodic homogenization). It is based on the double-layer theory and introduces an innovative concept of virtual electrolyte solution. First numerical results are given in a simple geometry (parallel platelets). In the next part are proposed numerical simulations of two kinds: response of the system to a chemical gradient and simulation of electro-osmosis. The end of this chapter puts into relief the necessity to integrate pH effects in the model. In the last part, chemical surface exchanges are incorporated in the modelling to understand pH and ionic force roles in electro-osmotic process. (author)

  14. Electro-optical properties of tetragonal KNbO3

    Indian Academy of Sciences (India)

    P U Sastry

    2007-06-01

    Linear electro-optical tensor coefficients and optical susceptibility of tetragonal KNbO3 are calculated using a formalism based on bond charge theory. Results are in close agreement with the experimental data. The covalent Nb–O bonding network comprising the distorted NbO6 octahedral groups in the structure is found to be a major contributor to the electro-optic coefficients making these groups more sensitive to these properties than the KO12 groups. The orientations of the chemical bonds play an important role in determining these properties.

  15. Decay of electric charge on corona charged polyethylene

    International Nuclear Information System (INIS)

    This paper describes a study on the surface potential decay of corona charged low density polyethylene (LDPE) films. A conventional corona charging process is used to deposit charge on the surface of film and surface potential is measured by a compact JCI 140 static monitor. The results from corona charged multilayer sample reveal that the bulk process dominates charge decay. In addition, the pulsed-electro-acoustic (PEA) technique has been employed to monitor charge profiles in corona charged LDPE films. By using the PEA technique, we are able to monitor charge migration through the bulk. Charge profiles in corona charged multilayer sample are consistent with surface potential results. Of further significance, the charge profiles clearly demonstrate that double injection has taken place in corona charged LDPE films

  16. The inverse electro-oculogram.

    OpenAIRE

    Doft, B H; Burns, S A; Elsner, A.

    1982-01-01

    An electro-oculogram ratio of less than one was found to be caused by limited ocular excursions under photopic conditions in a patient with a rod-cone dystrophy. Because this inverse electro-oculogram ratio was not caused by a decrease in standing potential under photopic conditions, it should be considered an artefact.

  17. Field-Effect Modulated Electro-Osmotic Pumps for High Precision Colloid Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The ability to precisely control the position of satellites is a critical enabling technology for space missions involving interferometric arrays. One proposed...

  18. Numerical characterization of silicon DC electro-osmotic pumps: the role of the micro channel geometry

    OpenAIRE

    Geri, M; Lorenzini, M.; Morini, GL; 3rd Micro and Nano Flows Conference (MNF2011)

    2011-01-01

    This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute. ...

  19. Electro-ultrafiltration of industrial enzyme solutions

    DEFF Research Database (Denmark)

    Enevoldsen, Ann Dorrit; Hansen, Erik Børresen; Jonsson, Gunnar Eigil

    2007-01-01

    To reduce the problems with fouling and concentration polarization during crossflow ultrafiltration of industrial enzyme solutions an electric field is applied across the membrane. The filtration performance during electro-ultrafiltration (EUF) has been tested with several enzymes. Results show...... that EUF is an effective method to filter high concentrated solutions at low crossfiow. The flux improved 3-7 times for enzymes with a significant surface charge at an electric field strength of 1600V/m compared to conventional UF. The greatest improvement is observed at high concentration. Not all...... enzymes can be filtered with EUF, mainly due to a low surface charge and impurities in the feed solution. Using a pulsed electric field did not improve the flux compared to a constant field. Gel electrophoresis experiments of the enzymes appear to be a useful method for estimating the influence of the...

  20. Electro-oxidation process for molybdenum concentrates

    Institute of Scientific and Technical Information of China (English)

    FU Jian-gang; ZHONG Hong; BU Xiang-ming; WANG Fu-li

    2005-01-01

    Sodium hypochlorite was used to treat the standard molybdenum concentrates; the oxidization conditions for sodium hypochlorite were investigated, and the electro-oxidation process was performed. The results indicate that in the suitable conditions, such as temperature around 25 ℃, NaCl concentration 4.0 mol/L, mass ratio of ore slurry liquid to solid (mL/mS) 20, electric charge per gram Mo 0.522 C, pH value of original slurry 8, anodic current density 700 A·m-2 (cell potential 2.7-2.9 V), the Mo leaching rate and the current efficiency reach 98% and 36%, respectively. In order to overcome some shortages of the electro-oxidation process, such as low current efficiency, low Mo concentration in the leaching solution, ultrasonic was adopted to intensify the leaching process. The results show that the Mo leaching rate exceeds 98%, current efficiency increases from 36% to 50% and the Mo concentration in the leaching solution reaches about 60 g/L at low mL/mS of 8 and low electric charge of 0.373 C.

  1. Physics of Bacteria During Osmotic Shock

    Science.gov (United States)

    Price, Jordan; Klug, William

    Bacteria combat hypoosmotic shocks by opening mechanosensitive ion channels located within the inner membrane. These channels are believed to act as ``emergency release valves,'' reducing transient pressure during the shock by regulating solute and water flux. Recent experiments have shown that cell survivability depends strongly on channel populations and the rate of osmotic shock. However, the understanding of the physical mechanisms behind osmotic protection remains unclear. We investigate how channel deletions, variations in shock rate, and cell envelope mechanics affect survivability by constructing theoretical elasticity and transport models. We find that reducing the number of channels and applying faster shocks significantly increases the time-dependent stress of the cell membrane and wall. This result provides insight into physical mechanisms that govern cell failure, including membrane rupture and wall fracture.

  2. Pulsatile lipid vesicles under osmotic stress

    CERN Document Server

    Chabanon, Morgan; Liedberg, Bo; Parikh, Atul N; Rangamani, Padmini

    2016-01-01

    The response of lipid bilayers to osmotic stress is an important part of cellular function. Previously, in [Oglecka et al. 2014], we reported that cell-sized giant unilamellar vesicles (GUVs) exposed to hypotonic media, respond to the osmotic assault by undergoing a cyclical sequence of swelling and bursting events, coupled to the membrane's compositional degrees of freedom. Here, we seek to deepen our quantitative understanding of the essential pulsatile behavior of GUVs under hypotonic conditions, by advancing a comprehensive theoretical model for vesicle dynamics. The model quantitatively captures our experimentally measured swell-burst parameters for single-component GUVs, and reveals that thermal fluctuations enable rate dependent pore nucleation, driving the dynamics of the swell-burst cycles. We further identify new scaling relationships between the pulsatile dynamics and GUV properties. Our findings provide a fundamental framework that has the potential to guide future investigations on the non-equili...

  3. Thermo-Osmotic Flow in Thin Films

    Science.gov (United States)

    Bregulla, Andreas P.; Würger, Alois; Günther, Katrin; Mertig, Michael; Cichos, Frank

    2016-05-01

    We report on the first microscale observation of the velocity field imposed by a nonuniform heat content along the solid-liquid boundary. We determine both radial and vertical velocity components of this thermo-osmotic flow field by tracking single tracer nanoparticles. The measured flow profiles are compared to an approximate analytical theory and to numerical calculations. From the measured slip velocity we deduce the thermo-osmotic coefficient for both bare glass and Pluronic F-127 covered surfaces. The value for Pluronic F-127 agrees well with Soret data for polyethylene glycol, whereas that for glass differs from literature values and indicates the complex boundary layer thermodynamics of glass-water interfaces.

  4. Thermo-osmotic flow in thin films

    CERN Document Server

    Bregulla, Andreas; Günther, Katrin; Mertig, Michael; Cichos, Frank

    2016-01-01

    We report on the first micro-scale observation of the velocity field imposed by a non-uniform heat content along the solid/liquid boundary. We determine both radial and vertical velocity components of this thermo-osmotic flow field by tracking single tracer nanoparticles. The measured flow profiles are compared to an approximate analytical theory and to numerical calculations. From the measured slip velocity we deduce the thermo-osmotic coefficient for both bare glass and Pluronic F-127 covered surfaces. The value for Pluronic F-127 agrees well with Soret data for polyethylene glycol, whereas that for glass differs from literature values and indicates the complex boundary layer thermodynamics of glass-water interfaces.

  5. Osmotically-assisted desalination method and system

    Science.gov (United States)

    Achilli, Andrea; Childress, Amy E.; Cath, Tzahi Y.

    2014-08-12

    Systems and methods for osmotically assisted desalination include using a pressurized concentrate from a pressure desalination process to pressurize a feed to the desalination process. The depressurized concentrate thereby produced is used as a draw solution for a pressure-retarded osmosis process. The pressure-retarded osmosis unit produces a pressurized draw solution stream that is used to pressurize another feed to the desalination process. In one example, the feed to the pressure-retarded osmosis process is impaired water.

  6. A REVIEW ON OSMOTIC DRUG DELIVERY SYSTEM

    OpenAIRE

    Harnish Patel; Upendra Patel; Hiren Kadikar; Bhavin Bhimani; Dhiren Daslaniya; Ghanshyam Patel

    2012-01-01

    Conventional oral drug delivery systems supply an instantaneous release of drug, which cannot control the release of the drug and effective concentration at the target site. This kind of dosing pattern may result in constantly changing, unpredictable plasma concentrations. Drugs can be delivered in a controlled pattern over a long period of time by the process of osmosis. Osmotic devices are the most promising strategy based systems for controlled drug delivery. They are the most reliable con...

  7. Asymmetric Membrane Osmotic Capsules for Terbutaline Sulphate

    OpenAIRE

    Gobade, N. G.; Marina Koland; K H Harish

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist...

  8. Hydrothermal Carbonization of Spent Osmotic Solution (SOS Generated from Osmotic Dehydration of Blueberries

    Directory of Open Access Journals (Sweden)

    Kaushlendra Singh

    2014-09-01

    Full Text Available Hydrothermal carbonization of spent osmotic solution (SOS, a waste generated from osmotic dehydration of fruits, has the potential of transformation into hydrochars, a value-added product, while reducing cost and overall greenhouse gas emissions associated with waste disposal. Osmotic solution (OS and spent osmotic solution (SOS generated from the osmotic dehydration of blueberries were compared for their thermo-chemical decomposition behavior and hydrothermal carbonization. OS and SOS samples were characterized for total solids, elemental composition, and thermo-gravimetric analysis (TGA. In addition, hydrothermal carbonization was performed at 250 °C and for 30 min to produce hydrochars. The hydrochars were characterized for elemental composition, Brunauer-Emmett-Teller (BET surface area, particle shape and surface morphology. TGA results show that the SOS sample loses more weight in the lower temperature range than the OS sample. Both samples produced, approximately, 40%–42% (wet-feed basis hydrochar during hydrothermal carbonization but with different properties. The OS sample produced hydrochar, which had spherical particles of 1.79 ± 1.30 μm diameter with a very smooth surface. In contrast, the SOS sample produced hydrochar with no definite particle shape but with a raspberry-like surface.

  9. Osmotic pressure of matter and vacuum energy

    CERN Document Server

    Volovik, G E

    2009-01-01

    The walls of the box which contains matter represent a membrane that allows the relativistic quantum vacuum to pass but not matter. That is why the pressure of matter in the box may be considered as the analog of the osmotic pressure. However, we demonstrate that the osmotic pressure of matter is modified due to interaction of matter with vacuum. This interaction induces the nonzero negative vacuum pressure inside the box, as a result the measured osmotic pressure becomes smaller than the matter pressure. As distinct from the Casimir effect, this induced vacuum pressure is the bulk effect and does not depend on the size of the box. This effect dominates in the thermodynamic limit of the infinite volume of the box. Analog of this effect has been observed in the dilute solution of 3He in liquid 4He, where the superfluid 4He plays the role of the non-relativistic quantum vacuum, and 3He atoms play the role of matter.

  10. OSMOTIC PUMP DRUG DELIVERY SYSTEM: A NOVAL APPROACH

    Directory of Open Access Journals (Sweden)

    Kashmir Singh

    2013-09-01

    Full Text Available Conventional drug delivery systems have little control over their drug release and almost no control over the effective concentration at the target site. The major problem associated with conventional drug delivery system is unpredictable plasma concentrations. Controlled drug delivery systems offer spatial control over the drug release. Osmotic pumps are most promising systems for controlled drug delivery. These systems are used for both oral administration and implantation. The present review is concerned with the study of drug release systems which are tablets coated with walls of controlled porosity. . Osmotic pump uses the basic principle of osmosis for release of drug(s. Osmotic pumps consist of an inner core containing drug and osmogens, coated with a semi permeable membrane. As the core absorbs water, it expands in volume, which pushes the drug solution out through the delivery ports. Osmotic pumps release drug at a rate that is independent of the pH and hydrodynamics of the dissolution medium. Various patents available for osmotic drug delivery system like Rose-Nelson pump, Higuchi-leeper pump, higuchi-theeuwes pump and elementary osmotic pump. In this paper, various types of osmotic pump and the basic components of  osmotic system tablets have been discussed briefly. Keywords: Osmosis, component of osmotic system, Osmotic pump

  11. Theoretical analysis of osmotic agents in peritoneal dialysis. What size is an ideal osmotic agent?

    Science.gov (United States)

    Rippe, B; Zakaria el-R; Carlsson, O

    1996-01-01

    In this article the difference between osmotic fluid flow (ultrafiltration) as driven by osmotic pressure and diffusion through thin leaky membranes is discussed. It is pointed out that water transport induced by osmosis is fundamentally different from the process of water diffusion. Applying modern hydrodynamic pore theory, the molar solute concentration and the solute concentration in grams per 100 mL, exerting the same initial transmembrane osmotic pressure as a 1% glucose solution, was investigated as a function of solute molecular weight (MW). It was then assumed, base on experimental data, that the major pathway responsible for the peritoneal osmotic barrier characteristics is represented by pores of radius approximately 47 A. With increasing solute radius, the osmotic reflection coefficient (sigma) and, hence, the osmotic efficiency per mole of solute will increase. However, simultaneously, the molar concentration per unit solute weight will decrease. The balance point between these two events apparently occurs at a solute MW of approximately 1 kDa. An additional advantage of using solutes of high MW as osmotic agents during peritoneal dialysis (PD), rather than increased osmotic efficiency per se, lies in the fact that large solutes, due to their low peritoneal diffusion capacity, will maintain a sustained rate of ultrafiltration (osmosis) over a prolonged period. To illustrate this, we have performed computer simulations of peritoneal fluid transport according to the three-pore model of peritoneal permselectivity. According to these simulations, 4% of an 800 Da polymer solution (+50 mmol/L above isotonicity) will produce the same cumulative amount of intraperitoneal fluid volume ultrafiltered (UF) during 360-400 minutes as 4% of a 2 kDa polymer solution (+20 mmol/L) or 6.5% of a 10 kDa polymer solution (+6.5 mmol/L) having the same electrolyte concentration as dialysis solutions conventionally used for PD. Similar cumulative UF volumes (during 400 minutes

  12. Astrocytes Are an Early Target in Osmotic Demyelination Syndrome

    OpenAIRE

    Gankam Kengne, Fabrice; Nicaise, Charles; Soupart, Alain; Boom, Alain; Schiettecatte, Johan; Pochet, Roland; Brion, Jean Pierre; Decaux, Guy

    2011-01-01

    Abrupt osmotic changes during rapid correction of chronic hyponatremia result in demyelinative brain lesions, but the sequence of events linking rapid osmotic changes to myelin loss is not yet understood. Here, in a rat model of osmotic demyelination syndrome, we found that massive astrocyte death occurred after rapid correction of hyponatremia, delineating the regions of future myelin loss. Astrocyte death caused a disruption of the astrocyte-oligodendrocyte network, rapidly upregulated infl...

  13. Compliant electro-thermal microactuators

    DEFF Research Database (Denmark)

    Jonsmann, Jacques; Sigmund, Ole; Bouwstra, Siebe

    1999-01-01

    This paper describes design, microfabrication and characterisation of topology optimised compliant electro-thermal microactuators. The actuators are fabricated by a fast prototyping process using laser micromachining and electroplating. Actuators are characterised with respect to displacement...

  14. Formulation and process optimization of multiparticulate pulsatile system delivered by osmotic pressure-activated rupturable membrane.

    Science.gov (United States)

    Hung, Sheng-Feng; Hsieh, Chien-Ming; Chen, Ying-Chen; Lin, Cheng-Mao; Ho, Hsiu-O; Sheu, Ming-Thau

    2015-03-01

    In this study, a multiparticulate pulsatile drug delivery system activated by a rupturable controlled-release membrane (Eudragit(®) RS) via osmotic pressure (with NaCl as the osmogent) was developed and characterized for omeprazole, omeprazole sodium, and propranolol HCl which have different water solubilities. Multiparticulates in pellet form for incorporation with or without the osmogent were manufactured by three methods and then used to coat a polymeric membrane. Results demonstrated that drug/osmogent-containing pellets manufactured by the extrusion/spheronization method with incorporation of the osmogent were optimal. The lag time (tL) to initiate pulsatile release is regulated by tL=l(2)/(6×D), which is dependent on the coating levels (l(2)) and plasticizer content (D). The pulsatile release pattern was found to be dependent on the osmotic pressure (osmogent), drug solubility, and mechanical properties of the polymeric membrane (elasticity and toughness). Omeprazole with lower water solubility could not generate sufficient osmotic pressure to create a crack in the membrane to activate pulsatile release, whereas the two other model drugs with higher solubilities could. But adsorption of omeprazole sodium on Eudragit(®) RS via charge-charge interactions led the its incomplete release. Finally, with 4% osmogent of NaCl added, a lag time in a range from 0 to 12h proportionally regulated by varying both the membrane thickness and plasticizer level initiated the complete pulsatile release of propranolol HCl. In conclusion, a multiparticulate pulsatile drug delivery system activated by a rupturable controlled-release membrane via osmotic pressure was successfully developed, and clinical applications of chronotherapy with drugs like propranolol HCl are expected. PMID:25575473

  15. A Simple Student Laboratory on Osmotic Flow, Osmotic Pressure, and the Reflection Coefficient.

    Science.gov (United States)

    Feher, Joseph J.; Ford, George D.

    1995-01-01

    Describes a laboratory exercise containing a practical series of experiments that novice students can perform within two hours. The exercise provides a confirmation of van't Hoff's law while placing more emphasis on osmotic flow than pressure. Students can determine parameters such as the reflection coefficient which stress the interaction of both…

  16. Geochemical effects of electro-osmosis in clays

    KAUST Repository

    Loch, J. P. Gustav

    2010-02-13

    Geochemical effects of electro-osmosis in bentonite clay are studied in the laboratory, where a 6 mm thick bentonite layer is subjected to direct current. Acidification and alkalization near anode and cathode are expected, possibly causing mineral deterioration, ion mobilization and precipitation of new solids. Afterwards the clay is analysed by XRF and anolyte and catholyte are analysed by ICP-MS. In addition, as a preliminary experiment treated bentonite is analysed by high resolution μ-XRF. Electro-osmotic flow is observed. Due to its carbonate content the bentonite is pH-buffering. Alkalization in the catholyte is substantial. Ca, Na and Sr are significantly removed from the clay and accumulate in the catholyte. Recovery in the catholyte accounts for a small fraction of the element-loss from the clay. The rest will have precipitated in undetected solid phases. μ-XRF indicates the loss of Ca-content throughout the bentonite layer. © The Author(s) 2010.

  17. The Balance of Fluid and Osmotic Pressures across Active Biological Membranes with Application to the Corneal Endothelium.

    Science.gov (United States)

    Cheng, Xi; Pinsky, Peter M

    2015-01-01

    The movement of fluid and solutes across biological membranes facilitates the transport of nutrients for living organisms and maintains the fluid and osmotic pressures in biological systems. Understanding the pressure balances across membranes is crucial for studying fluid and electrolyte homeostasis in living systems, and is an area of active research. In this study, a set of enhanced Kedem-Katchalsky (KK) equations is proposed to describe fluxes of water and solutes across biological membranes, and is applied to analyze the relationship between fluid and osmotic pressures, accounting for active transport mechanisms that propel substances against their concentration gradients and for fixed charges that alter ionic distributions in separated environments. The equilibrium analysis demonstrates that the proposed theory recovers the Donnan osmotic pressure and can predict the correct fluid pressure difference across membranes, a result which cannot be achieved by existing KK theories due to the neglect of fixed charges. The steady-state analysis on active membranes suggests a new pressure mechanism which balances the fluid pressure together with the osmotic pressure. The source of this pressure arises from active ionic fluxes and from interactions between solvent and solutes in membrane transport. We apply the proposed theory to study the transendothelial fluid pressure in the in vivo cornea, which is a crucial factor maintaining the hydration and transparency of the tissue. The results show the importance of the proposed pressure mechanism in mediating stromal fluid pressure and provide a new interpretation of the pressure modulation mechanism in the in vivo cornea. PMID:26719894

  18. The Balance of Fluid and Osmotic Pressures across Active Biological Membranes with Application to the Corneal Endothelium.

    Directory of Open Access Journals (Sweden)

    Xi Cheng

    Full Text Available The movement of fluid and solutes across biological membranes facilitates the transport of nutrients for living organisms and maintains the fluid and osmotic pressures in biological systems. Understanding the pressure balances across membranes is crucial for studying fluid and electrolyte homeostasis in living systems, and is an area of active research. In this study, a set of enhanced Kedem-Katchalsky (KK equations is proposed to describe fluxes of water and solutes across biological membranes, and is applied to analyze the relationship between fluid and osmotic pressures, accounting for active transport mechanisms that propel substances against their concentration gradients and for fixed charges that alter ionic distributions in separated environments. The equilibrium analysis demonstrates that the proposed theory recovers the Donnan osmotic pressure and can predict the correct fluid pressure difference across membranes, a result which cannot be achieved by existing KK theories due to the neglect of fixed charges. The steady-state analysis on active membranes suggests a new pressure mechanism which balances the fluid pressure together with the osmotic pressure. The source of this pressure arises from active ionic fluxes and from interactions between solvent and solutes in membrane transport. We apply the proposed theory to study the transendothelial fluid pressure in the in vivo cornea, which is a crucial factor maintaining the hydration and transparency of the tissue. The results show the importance of the proposed pressure mechanism in mediating stromal fluid pressure and provide a new interpretation of the pressure modulation mechanism in the in vivo cornea.

  19. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  20. Osmotic stress on nitrification in an airlift bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jin Rencun [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China); Zheng Ping [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China); Mahmood, Qaisar [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China); Hu Baolan [Department of Environmental Engineering, Zhejiang University, Hangzhou 310029 (China)]. E-mail: blhu@zju.edu.cn

    2007-07-19

    The effect of osmotic pressure on nitrification was studied in a lab-scale internal-loop airlift-nitrifying reactor. The reactor slowly adapted to the escalating osmotic pressure during 270 days operation. The conditions were reversed to the initial stage upon full inhibition of the process. Keeping influent ammonium concentration constant at 420 mg N L{sup -1} and hydraulic retention time at 20.7 h, with gradual increase in osmotic pressure from 4.3 to 18.8 x 10{sup 5} Pa by adding sodium sulphate, the ammonium removal efficiencies of the nitrifying bioreactor were maintained at 93-100%. Further increase in osmotic pressure up to 19.2 x 10{sup 5} Pa resulted in drop of the ammonium conversion to 69.2%. The osmotic pressure caused abrupt inhibition of nitrification without any alarm and the critical osmotic pressure value causing inhibition remained between 18.8 and 19.2 x 10{sup 5} Pa. Nitrite oxidizers were found more sensitive to osmotic stress as compared with ammonia oxidizers, leading to nitrite accumulation up to 61.7% in the reactor. The performance of bioreactor recovered gradually upon lowering the osmotic pressure. Scanning and transmission electron microscopy indicated that osmotic stress resulted in simplification of the nitrifying bacterial populations in the activated sludge as the cellular size reduced; the inner membrane became thinner and some unknown inclusions appeared within the cells. The microbial morphology and cellular structure restored upon relieving the osmotic pressure. Addition of potassium relieved the effect of osmotic pressure upon nitrification. Results demonstrate that the nitrifying reactor possesses the potential to treat ammonium-rich brines after acclimatization.

  1. Osmotic stress on nitrification in an airlift bioreactor

    International Nuclear Information System (INIS)

    The effect of osmotic pressure on nitrification was studied in a lab-scale internal-loop airlift-nitrifying reactor. The reactor slowly adapted to the escalating osmotic pressure during 270 days operation. The conditions were reversed to the initial stage upon full inhibition of the process. Keeping influent ammonium concentration constant at 420 mg N L-1 and hydraulic retention time at 20.7 h, with gradual increase in osmotic pressure from 4.3 to 18.8 x 105 Pa by adding sodium sulphate, the ammonium removal efficiencies of the nitrifying bioreactor were maintained at 93-100%. Further increase in osmotic pressure up to 19.2 x 105 Pa resulted in drop of the ammonium conversion to 69.2%. The osmotic pressure caused abrupt inhibition of nitrification without any alarm and the critical osmotic pressure value causing inhibition remained between 18.8 and 19.2 x 105 Pa. Nitrite oxidizers were found more sensitive to osmotic stress as compared with ammonia oxidizers, leading to nitrite accumulation up to 61.7% in the reactor. The performance of bioreactor recovered gradually upon lowering the osmotic pressure. Scanning and transmission electron microscopy indicated that osmotic stress resulted in simplification of the nitrifying bacterial populations in the activated sludge as the cellular size reduced; the inner membrane became thinner and some unknown inclusions appeared within the cells. The microbial morphology and cellular structure restored upon relieving the osmotic pressure. Addition of potassium relieved the effect of osmotic pressure upon nitrification. Results demonstrate that the nitrifying reactor possesses the potential to treat ammonium-rich brines after acclimatization

  2. Osmotic barrier of the parietal peritoneum.

    Science.gov (United States)

    Flessner, M F

    1994-11-01

    Fluid movement into the peritoneal cavity results after instillation of a hypertonic solution. Some investigators have assumed that the peritoneum is a significant barrier to small solutes and have predicted that fluid would be drawn by an osmotic gradient into the cavity from the tissue surrounding the peritoneal cavity, resulting in tissue hydrostatic pressures well below atmospheric pressure. Contrary to this, we have previously shown that protein and fluid cross the peritoneum and enter the tissue at the same rate during either isotonic or hypertonic dialysis. To investigate the nature of the osmotic barrier of the peritoneum, the hydrostatic pressure profiles were measured in the abdominal wall of the rat during conditions of either isotonicity or hypertonicity in the peritoneal cavity and constant intraperitoneal hydrostatic pressure (Pip). Measurements were made with a micropipette mounted on a micromanipulator and connected to a servo-null pressure measurement system. No interstitial pressures below atmospheric pressure were observed with either type of solution in the peritoneal cavity. For the three Pip values tested, there were few significant differences between the corresponding pressure profiles of isotonic or hypertonic solutions. It is concluded that the parietal peritoneum is not a functional barrier to small solutes, which are often used to raise the osmolality of intraperitoneal solutions. This finding also implies that the tissue interstitium underlying the parietal peritoneum is not the source of water flow into the cavity, which is observed during hypertonic dialysis. PMID:7977791

  3. Electrostatic interaction between nonuniformly charged colloids: experimental and numerical study.

    Science.gov (United States)

    Derot, Claire; Porcar, Lionel; Lee, YongJin; Pincus, Phillip A; Jho, YongSeok; In, Martin

    2015-02-10

    The influence of the surface charge distribution on the interaction between nanosized particles in water is reported. The distribution of charges at the surface of initially neutral microemulsion droplets has been modulated by additions of various oligomeric cationic surfactants. The osmotic compressibility of the doped microemulsions was measured by light and small-angle neutrons scattering and reveals that the overall effective interaction induced by the ionic groups is repulsive. However, particular charge distributions decrease the osmotic compressibility much less than others. Independent measurements of the activity of the bromide counterions with specific electrodes evidence a significant decrease in the effective charge, which, however, cannot account for the osmotic compressibility in the framework of the primitive model. The q dependence of the structure factor reveals an attractive contribution over a short distance. Numerical studies assign this attractive contribution to the overlap of hydration shells that are extended as a result of the charge localization. PMID:25587999

  4. Osmotic Power: A Fresh Look at an Old Experiment

    Science.gov (United States)

    Dugdale, Pam

    2014-01-01

    Electricity from osmotic pressure might seem a far-fetched idea but this article describes a prototype in Norway where the osmotic pressure generated between salt and fresh water drives a turbine. This idea was applied in a student investigation, where they were tasked with researching which alternative materials could be used for the…

  5. Removal of PAHs from contaminated clayey soil by means of electro-osmosis

    KAUST Repository

    Lima, Ana T.

    2011-06-01

    The removal of polycyclic aromatic hydrocarbons (PAHs) from clayey soils is an intricate task. The low porosity of compacted clayey soil hinders bacterial activity and makes convective removal by hydraulic flow impossible. Electro-osmosis is a process that has been used for the mobilization and cleanup of contaminants in clayey soils with varying successes. The present study focuses on the remediation of a contaminated peaty clay soil, located in Olst - the Netherlands, by means of electro-osmosis. The soil was originally contaminated by an asphalt production plant, active from 1903 to 1983, and presents high levels of all 16 priority PAHs indicated by the US Environmental Protection Agency (EPA). Such a long contact times of PAH with the soil (≥100 years) presents a unique study material with well established solid/liquid contaminant partitioning equilibrium, preferable to artificially spiked soil. A batch of 6 electro-osmosis laboratory experiments was carried out to study the removal of 16 PAHs through electro-osmosis. In these experiments, water and a surfactant (Tween 80) were used to enhance the PAH desorption. The electro-osmotic conductivities ranged from 2.88 × 10-10 to a substantial 1.19 × 10-7 m2 V-1 s -1 when applying a current density of 0.005-0.127 A m-2. Electro-osmosis was expected to occur towards the cathode, because of natural soil characteristics (negative zeta potential), but presented scattered directions. The use of reference electrodes proved to be very effective to the prediction of the flow direction. Finally, the addition of Tween 80 as a surfactant enhanced PAH removal up to 30% of the total PAH content of the soil in 9 days. © 2011 Elsevier B.V.

  6. Refinement of elastic, poroelastic, and osmotic tissue properties of intervertebral disks to analyze behavior in compression.

    Science.gov (United States)

    Stokes, Ian A F; Laible, Jeffrey P; Gardner-Morse, Mack G; Costi, John J; Iatridis, James C

    2011-01-01

    Intervertebral disks support compressive forces because of their elastic stiffness as well as the fluid pressures resulting from poroelasticity and the osmotic (swelling) effects. Analytical methods can quantify the relative contributions, but only if correct material properties are used. To identify appropriate tissue properties, an experimental study and finite element analytical simulation of poroelastic and osmotic behavior of intervertebral disks were combined to refine published values of disk and endplate properties to optimize model fit to experimental data. Experimentally, nine human intervertebral disks with adjacent hemi-vertebrae were immersed sequentially in saline baths having concentrations of 0.015, 0.15, and 1.5 M and the loss of compressive force at constant height (force relaxation) was recorded over several hours after equilibration to a 300-N compressive force. Amplitude and time constant terms in exponential force-time curve-fits for experimental and finite element analytical simulations were compared. These experiments and finite element analyses provided data dependent on poroelastic and osmotic properties of the disk tissues. The sensitivities of the model to alterations in tissue material properties were used to obtain refined values of five key material parameters. The relaxation of the force in the three bath concentrations was exponential in form, expressed as mean compressive force loss of 48.7, 55.0, and 140 N, respectively, with time constants of 1.73, 2.78, and 3.40 h. This behavior was analytically well represented by a model having poroelastic and osmotic tissue properties with published tissue properties adjusted by multiplying factors between 0.55 and 2.6. Force relaxation and time constants from the analytical simulations were most sensitive to values of fixed charge density and endplate porosity. PMID:20711754

  7. Osmotic and motional properties of intracellular water as influenced by osmotic swelling and shrinkage of Xenopus oocytes.

    Science.gov (United States)

    Cameron, I L; Merta, P; Fullerton, G D

    1990-03-01

    Experiments were done on fully grown Xenopus oocytes to determine the extent and the properties of cellular water of hydration. The studies involved the osmotic shrinking and swelling of the oocytes under known osmotic pressure as well as proton NMR spectral, titration, and free induction decay analyses. Studies were done both on whole oocytes and on subcellular fractions. The results show that little if any of the oocyte water in situ has the motional or osmotic properties expected of pure "bulk" water. Four distinct water of hydration compartments were found and defined on the basis of distinct hydrogen bounding mechanisms. Some of the water in yolk platelets was found not to be in fast exchange with other water compartments. Osmotic shrinkage of oocytes caused an adaptive decrease in the bound water of hydration compartments. This osmotically induced decrease is attributed to decreased surface area available for the hydrogen bounding of water molecules on cellular proteins. PMID:2312616

  8. Electro-Optic System Development Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Electro-Optic System Development Lab serves as a development facility for electro-optical systems ranging from visible through long wave infrared. Capabilities...

  9. Electromigration of Contaminated Soil by Electro-Bioremediation Technique

    Science.gov (United States)

    Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Shaylinda, M. Z. N.; Azim, M. A. M.

    2016-07-01

    Soil contamination with heavy metals poses major environmental and human health problems. This problem needs an efficient method and affordable technological solution such as electro-bioremediation technique. The electro-bioremediation technique used in this study is the combination of bacteria and electrokinetic process. The aim of this study is to investigate the effectiveness of Pseudomonas putida bacteria as a biodegradation agent to remediate contaminated soil. 5 kg of kaolin soil was spiked with 5 g of zinc oxide. During this process, the anode reservoir was filled with Pseudomonas putida while the cathode was filled with distilled water for 5 days at 50 V of electrical gradient. The X-Ray Fluorescent (XRF) test indicated that there was a significant reduction of zinc concentration for the soil near the anode with 89% percentage removal. The bacteria count is high near the anode which is 1.3x107 cfu/gww whereas the bacteria count at the middle and near the cathode was 5.0x106 cfu/gww and 8.0x106 cfu/gww respectively. The migration of ions to the opposite charge of electrodes during the electrokinetic process resulted from the reduction of zinc. The results obtained proved that the electro-bioremediation reduced the level of contaminants in the soil sample. Thus, the electro-bioremediation technique has the potential to be used in the treatment of contaminated soil.

  10. Flow patterns and heat transfer in electro-thermo-convection

    International Nuclear Information System (INIS)

    In this article we study the electro-thermo-convective phenomena in a dielectric liquid layer placed between two electrodes and subjected to the simultaneous action of an electric field and a thermal gradient. The full set of coupled equations: Navier-Stokes, Electro-Hydro-Dynamic (EHD) and Heat Transfer equations are directly solved in a 2D cavity using a finite volume method. In order to characterize the influence of the electric field on heat transfer we first heat the liquid till the thermal steady state is obtained and then apply the electric potential and charge are injected from the lower electrode. Two cases of heating are considered: from the lower electrode and from a lateral wall (left or right). We show that both flow pattern and Nusselt number strongly depend on the following non-dimensional characteristic parameters: electrical parameter, Rayleigh number, Prandtl number and mobility parameter. The development of the convective motion passing from a purely thermal convection to a purely electrical convection is investigated as well as the number of electro-thermo-convective rolls. As a consequence of the analysis of the combined effect of electric and thermal fields on the flow structure and on Nusselt number, we have also evaluated the heat transfer enhancement due to electro-convection.

  11. Analysing transfer phenomena in osmotic evaporation

    Directory of Open Access Journals (Sweden)

    Freddy Forero Longas

    2011-12-01

    Full Text Available Osmotic evaporation is a modification of traditional processes using membranes; by means of a vapour pressure differential, produced by a highly concentrated extraction solution, water is transferred through a hydrophobic membrane as vapour. This technique has many advantages over traditional processes, allowing work at atmospheric pressure and low temperatures, this being ideal for heatsensitive products. This paper presents and synthetically analyses the phenomena of heat and mass transfer which occurs in the process and describes the models used for estimating the parameters of interest, such as flow, temperature, heat transfer rate and the relationships that exist amongst them when hollow fibre modules are used, providing a quick reference tool and specific information about this process.

  12. Asymmetric membrane osmotic capsules for terbutaline sulphate

    Directory of Open Access Journals (Sweden)

    N G Gobade

    2012-01-01

    Full Text Available The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate.

  13. Asymmetric membrane osmotic capsules for terbutaline sulphate.

    Science.gov (United States)

    Gobade, N G; Koland, Marina; Harish, K H

    2012-01-01

    The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate. PMID:23204625

  14. Optimisation of mass transfer kinetics during osmotic dehydration of pork meat cubes in complex osmotic solution

    Directory of Open Access Journals (Sweden)

    Filipović Vladimir

    2014-01-01

    Full Text Available This paper presents the effects of different process temperature (20, 35 and 50 °C, immersion time (1, 3 and 5 hours and the concentration of sugar beet molasses + NaCl + sucrose water solution on osmotic dehydration of pork meat (M. triceps brachii cubes, shaped 1 x 1 x 1 cm, at atmospheric pressure. The main objective was to examine the influence of different parameters on the mass transfer kinetics during osmotic treatment. The observed system’s responses were: water loss, solid gain, and water activity. The optimum osmotic conditions (temperature of 40 °C, treatment time of 4.1 h and concentration 67 %, were determined using response surface method, by superimposing the contour plots of each process variable, and the responses were: water loss=0.46, solid gain=0.15, and water activity=0.79. Transport coefficients, for both solids and water transfer and energy of activation for all samples were also determined. [Projekat Ministarstva nauke Republike Srbije, br. TR-31055

  15. Attraction between like-charge surfaces in polar mixtures

    OpenAIRE

    Samin, Sela; Tsori, Yoav

    2011-01-01

    We examine the force between two charged surfaces immersed in aqueous mixtures having a coexistence curve. For a homogeneous water-poor phase, as the distance between the surfaces is decreased, a water-rich phase condenses at a distance $D_t$ in the range 1-100nm. At this distance the osmotic pressure can become negative leading to a long-range attraction between the surfaces. The osmotic pressure vanishes at a distance $D_e

  16. Salt Effect on Osmotic Pressure of Polyelectrolyte Solutions: Simulation Study

    Directory of Open Access Journals (Sweden)

    Jan-Michael Y. Carrillo

    2014-07-01

    Full Text Available Abstract: We present results of the hybrid Monte Carlo/molecular dynamics simulations of the osmotic pressure of salt solutions of polyelectrolytes. In our simulations, we used a coarse-grained representation of polyelectrolyte chains, counterions and salt ions. During simulation runs, we alternate Monte Carlo and molecular dynamics simulation steps. Monte Carlo steps were used to perform small ion exchange between simulation box containing salt ions (salt reservoir and simulation box with polyelectrolyte chains, counterions and salt ions (polyelectrolyte solution. This allowed us to model Donnan equilibrium and partitioning of salt and counterions across membrane impermeable to polyelectrolyte chains. Our simulations have shown that the main contribution to the system osmotic pressure is due to salt ions and osmotically active counterions. The fraction of the condensed (osmotically inactive counterions first increases with decreases in the solution ionic strength then it saturates. The reduced value of the system osmotic coefficient is a universal function of the ratio of the concentration of osmotically active counterions and salt concentration in salt reservoir. Simulation results are in a very good agreement with osmotic pressure measurements in sodium polystyrene sulfonate, DNA, polyacrylic acid, sodium polyanetholesulfonic acid, polyvinylbenzoic acid, and polydiallyldimethylammonium chloride solutions.

  17. Osmotically regulated transport of proline by Lactobacillus acidophilus IFO 3532.

    Science.gov (United States)

    Jewell, J B; Kashket, E R

    1991-10-01

    We reported previously that, when exposed to high osmotic pressure, Lactobacillus acidophilus IFO 3532 cells accumulated N,N,N-trimethylglycine (glycine betaine), which serves as a compatible intracellular solute. When grown in medium with high osmotic pressure, these cells also accumulated one amino acid, proline. The uptake of [3H]proline by resting, glucose-energized cells was stimulated by increasing the osmotic pressure of the assay medium with 0.5 to 1.0 M KCl, 1.0 M NaCl, or 0.5 M sucrose. The accumulated [3H]proline was not metabolized further. In contrast, there was no osmotic stimulation of [3H]leucine uptake. The uptake of proline was activated rather than induced by exposure of the cells to high osmotic pressure. Only one proline transport system could be discerned from kinetics plots. The affinity of the carrier for proline remained constant over a range of osmotic pressures from 650 to 1,910 mosM (Kt, 7.8 to 15.5 mM). The Vmax, however, increased from 15 nmol/min/mg of dry weight in 0.5 M sucrose to 27 and 40 nmol/min/mg of dry weight in 0.5 M KCl and in 1.0 M KCl or NaCl, respectively. The efflux of proline from preloaded cells occurred rapidly when the osmotic pressure of the suspending buffer was lowered. PMID:1786048

  18. Development and optimization of buspirone oral osmotic pump tablet.

    Science.gov (United States)

    Derakhshandeh, K; Berenji, M Ghasemnejad

    2014-01-01

    The aim of the current study was to design a porous osmotic pump-based drug delivery system for controlling the release of buspirone from the delivery system. The osmotic pump was successfully developed using symmetric membrane coating. The core of the tablets was prepared by direct compression technique and coated using dip-coating technique. Drug release from the osmotic system was studied using USP paddle type apparatus. The effect of various processing variables such as the amount of osmotic agent, the amount of swellable polymer, concentration of the core former, concentration of the plasticizer, membrane thickness, quantum of orifice on drug release from osmotic pump were evaluated. Different kinetic models (zero order, first order and Higuchi model) were applied to drug release data in order to establish the kinetics of drug release. It was found that the drug release was mostly affected by the amount of NaCl as osmotic agent, the swellable polymer; hydroxy propyl methyl cellulose (HPMC), the amount of PEG-400 and cellulose acetate in the coating solution and thickness of the semipermeable membrane. The optimized formulation released buspirone independent of pH and orifice quantum at the osmogen amount of 42%, hydrophilic polymer of 13% and pore size of 0.8 mm on the tablet surface. The drug release of osmotic formulation during 24 h showed zero order kinetics and could be suggested that this formulation as a once-daily regimen improves pharmacokinetic parameters of the drug and enhances patient compliance. PMID:25657794

  19. Influence of osmotic processes on the excess-hydraulic head measured in the Toarcian/Domerian argillaceous formation of Tournemire

    International Nuclear Information System (INIS)

    In the framework of the studies dealing on ability to store radioactive wastes in argillaceous formations, signification of interstitial pressures is an important point to understand water and solutes transport. In very low permeability argillaceous formations, like those studied in the Callovo-Oxfordian of the Paris basin by ANDRA, pore pressure is frequently higher than the theoretical hydrostatic pressure or than the pressure in the surrounding aquifers. Such an overpressure is also measured in the Toarcian/Domerian argillaceous formation (k = 10-21m2), studied by the IRSN in the underground research laboratory of Tournemire (Aveyron, France). The hydraulic head profile has been specified in this manuscript and found to present a 30 ±10 m excess head. This excess-head can be due to compaction disequilibrium of the argillaceous formation, diagenetic evolution of the rock, tectonic compression, changes in hydrodynamic boundary conditions or osmotic processes. Amongst these potential causes, chemical osmosis and thermo-osmosis, a fluid flow under a chemical concentration and a temperature gradient, respectively, are expected to develop owing to the small pore size and the electrostatic interactions related to the charged surface of clay minerals. The goal of the work presented here was to study and quantify the contribution of each cause to the measured excess-head. Chemo-osmotic and thermo-osmotic permeabilities were obtained by experiments and using theoretical models. Theoretical models are based on the reproduction of the interactions occurring between the charged surface of clay minerals and pore solution and their up-scaling at the representative elementary volume macroscopic scale. Chemical osmosis phenomenon is related to anionic exclusion and the determination of the chemo-osmotic efficiency requires the resolution of an electrical interactions model. A triple-layer-model which considers diffuse layers overlapping was improved during this thesis to be

  20. Self-assembly of silk fibroin under osmotic stress

    Science.gov (United States)

    Sohn, Sungkyun

    The supramolecular self-assembly behavior of silk fibroin was investigated using osmotic stress technique. In Chapter 2, a ternary phase diagram of water-silk-LiBr was constructed based on X-ray results on the osmotically stressed regenerated silk fibroin of Bombyx mori silkworm. Microscopic data indicated that silk I is a hydrated structure and a rough estimate of the number of water molecules lost by the structure upon converting from silk I to silk II has been made, and found to be about 2.2 per [GAGAGS] hexapeptide. In Chapter 3, wet-spinning of osmotically stressed, regenerated silk fibroin was performed, based on the prediction that the enhanced control over structure and phase behavior using osmotic stress method helps improve the physical properties of wet-spun regenerated silk fibroin fibers. The osmotic stress was applied in order to pre-structure the regenerated silk fibroin molecule from its original random coil state to more oriented state, manipulating the phase of the silk solution in the phase diagram before the start of spinning. Monofilament fiber with a diameter of 20 microm was produced. In Chapter 4, we investigated if there is a noticeable synergistic osmotic pressure increase between co-existing polymeric osmolyte and salt when extremely highly concentrated salt molecules are present both at sample subphase and stressing subphase, as is the case of silk fibroin self-assembly. The equilibration method that measures osmotic pressure relative to a reference with known osmotic pressure was introduced. Osmotic pressure of aqueous LiBr solution up to 2.75M was measured and it was found that the synergistic effect was insignificant up to this salt concentration. Solution parameters of stressing solutions and Arrhenius kinetics based on time-temperature relationship for the equilibration process were derived as well. In Chapter 5, self-assembly behavior of natural silk fibroin within the gland of Bombyx mori silkworm was investigated using osmotic

  1. Osmotically Regulated Transport of Proline by Lactobacillus acidophilus IFO 3532

    OpenAIRE

    Jewell, J. B.; Kashket, E R

    1991-01-01

    We reported previously that, when exposed to high osmotic pressure, Lactobacillus acidophilus IFO 3532 cells accumulated N,N,N-trimethylglycine (glycine betaine), which serves as a compatible intracellular solute. When grown in medium with high osmotic pressure, these cells also accumulated one amino acid, proline. The uptake of [3H]proline by resting, glucose-energized cells was stimulated by increasing the osmotic pressure of the assay medium with 0.5 to 1.0 M KCl, 1.0 M NaCl, or 0.5 M sucr...

  2. Enhancing the brightness of Si nanocrystal light-emitting devices with electro-excited surface plasmons

    International Nuclear Information System (INIS)

    The use of electro-excited surface plasmons (SPs) in Ag nanoparticles (Ag-NPs) is shown to enhance the brightness of Si nanocrystal light-emitting devices (Si-NC LEDs). The Ag-NPs are prepared on the Si-NC thin film by ultrasonic irradiation and postannealing treatments. Electro-excited SPs on Ag-NPs are found, which are induced by electron impact on Ag-NPs and the front electrode Al layer during the charge injection process of LED. The electro-excited SPs enhance the electroluminescence of Si-NC, or LED brightness, via the SP field coupling to the exciton dipole moment of Si-NC. A maximal 5.2-fold brightness enhancement of Si-NC LED is achieved at the postannealing temperature of 200 °C. Remnant far-field radiations arising from electro-excited SPs are detected, which further supports the existence of such SPs. (paper)

  3. Enhancing the brightness of Si nanocrystal light-emitting devices with electro-excited surface plasmons

    Science.gov (United States)

    Chen, Jia-Rong; Zhou, Zhi-Quan; Hao, Hong-Chen; Lu, Ming

    2014-09-01

    The use of electro-excited surface plasmons (SPs) in Ag nanoparticles (Ag-NPs) is shown to enhance the brightness of Si nanocrystal light-emitting devices (Si-NC LEDs). The Ag-NPs are prepared on the Si-NC thin film by ultrasonic irradiation and postannealing treatments. Electro-excited SPs on Ag-NPs are found, which are induced by electron impact on Ag-NPs and the front electrode Al layer during the charge injection process of LED. The electro-excited SPs enhance the electroluminescence of Si-NC, or LED brightness, via the SP field coupling to the exciton dipole moment of Si-NC. A maximal 5.2-fold brightness enhancement of Si-NC LED is achieved at the postannealing temperature of 200 °C. Remnant far-field radiations arising from electro-excited SPs are detected, which further supports the existence of such SPs.

  4. Electro-optic techniques in electron beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    van Tilborg, Jeroen; Toth, Csaba; Matlis, Nicholas; Plateau, Guillaume; Leemans, Wim

    2011-06-17

    Electron accelerators such as laser wakefield accelerators, linear accelerators driving free electron lasers, or femto-sliced synchrotrons, are capable of producing femtosecond-long electron bunches. Single-shot characterization of the temporal charge profile is crucial for operation, optimization, and application of such accelerators. A variety of electro-optic sampling (EOS) techniques exists for the temporal analysis. In EOS, the field profile from the electron bunch (or the field profile from its coherent radiation) will be transferred onto a laser pulse co-propagating through an electro-optic crystal. This paper will address the most common EOS schemes and will list their advantages and limitations. Strong points that all techniques share are the ultra-short time resolution (tens of femtoseconds) and the single-shot capabilities. Besides introducing the theory behind EOS, data from various research groups is presented for each technique.

  5. Electro-optic techniques in electron beam diagnostics

    International Nuclear Information System (INIS)

    Electron accelerators such as laser wakefield accelerators, linear accelerators driving free electron lasers, or femto-sliced synchrotrons, are capable of producing femtosecond-long electron bunches. Single-shot characterization of the temporal charge profile is crucial for operation, optimization, and application of such accelerators. A variety of electro-optic sampling (EOS) techniques exists for the temporal analysis. In EOS, the field profile from the electron bunch (or the field profile from its coherent radiation) will be transferred onto a laser pulse co-propagating through an electro-optic crystal. This paper will address the most common EOS schemes and will list their advantages and limitations. Strong points that all techniques share are the ultra-short time resolution (tens of femtoseconds) and the single-shot capabilities. Besides introducing the theory behind EOS, data from various research groups is presented for each technique.

  6. Microfluidic System Simulation Including the Electro-Viscous Effect

    Science.gov (United States)

    Rojas, Eileen; Chen, C. P.; Majumdar, Alok

    2007-01-01

    This paper describes a practical approach using a general purpose lumped-parameter computer program, GFSSP (Generalized Fluid System Simulation Program) for calculating flow distribution in a network of micro-channels including electro-viscous effects due to the existence of electrical double layer (EDL). In this study, an empirical formulation for calculating an effective viscosity of ionic solutions based on dimensional analysis is described to account for surface charge and bulk fluid conductivity, which give rise to electro-viscous effect in microfluidics network. Two dimensional slit micro flow data was used to determine the model coefficients. Geometry effect is then included through a Poiseuille number correlation in GFSSP. The bi-power model was used to calculate flow distribution of isotropically etched straight channel and T-junction microflows involving ionic solutions. Performance of the proposed model is assessed against experimental test data.

  7. Mechanism of actuation in conducting polymers: Osmotic expansion

    DEFF Research Database (Denmark)

    Bay, Lasse; Jacobsen, Torben; West, Keld;

    2001-01-01

    Conducting polymers expand or contract when their redox state is changed. This expansion/contraction effect can be separated in an intrinsic part because of changes of the polymer backbone on reduction/oxidation and a part depending on the surrounding electrolyte phase, because of osmotic expansi...... and designing actuator experiments and when comparing experimental results from different sources.......Conducting polymers expand or contract when their redox state is changed. This expansion/contraction effect can be separated in an intrinsic part because of changes of the polymer backbone on reduction/oxidation and a part depending on the surrounding electrolyte phase, because of osmotic expansion...... of the polymer phase. The osmotic effect causes solvent molecules to move into the polymer in a number far in excess of those bound strongly in the solvation shell of the mobile ion, resulting in large volume changes. In this paper, a thermodynamic description of the osmotic expansion is worked out. The model...

  8. An evaluation of the osmotic method of controlling suction

    CERN Document Server

    Delage, Pierre

    2008-01-01

    Experimental techniques of testing the mechanical properties of unsaturated soils are complex and difficult to conduct. As a consequence, complete sets of parameters that characterise the behaviour of unsaturated soils remain scarce and necessary. In this context, it has been found useful to gather the information obtained after some years of practice of the osmotic technique of controlling suction. As compared to the more documented axis-translation technique, the osmotic technique has its own advantages and drawbacks that are discussed in this paper, together with some potential future developments. The osmotic method has been developed by soil scientists in the 1960s and adapted to geotechnical testing in the early 1970s. This paper presents the osmotic technique and comments on its advantages (including suction condition close to reality and higher suctions easily attained) and drawbacks (including some concern with the membrane resistance and some membrane effects in the suction/concentration calibration...

  9. Plant response to sunflower seeds to osmotic conditioning

    Directory of Open Access Journals (Sweden)

    Camila Santos Barros de Morais

    2014-10-01

    Full Text Available The aim of this study was to evaluate the effect of seeds osmotic conditioning in seedlings emergence and plants performance of sunflower. Three lots of seeds sunflower (Catissol, was submited to osmotic conditioning with polyethylene glycol solution, –2,0 MPa in aerated system, under 15 ºC for 8 hour and then was evaluated for germination tests and vigour. Under filed conditions was conducted emergency evaluations of seedling, plants development as well as the productivity and seeds quality, and the accumulation of nutrients in the seeds. The osmotic conditioning improve the survival of seedling, the dry matter mass to aerial part of plants from 60 days after sowing and oil content, in lots with low seeds physiological quality. The osmotic conditioning not increase the seeds yield but promotes the vigour of seeds produced, regardless of the lot used for sowing seeds.

  10. Osmotic pressure: resisting or promoting DNA ejection from phage

    CERN Document Server

    Jeembaeva, Meerim; Larsson, Frida; Evilevitch, Alex

    2008-01-01

    Recent in vitro experiments have shown that DNA ejection from bacteriophage can be partially stopped by surrounding osmotic pressure when ejected DNA is digested by DNase I on the course of ejection. We argue in this work by combination of experimental techniques (osmotic suppression without DNaseI monitored by UV absorbance, pulse-field electrophoresis, and cryo-EM visualization) and simple scaling modeling that intact genome (i.e. undigested) ejection in a crowded environment is, on the contrary, enhanced or eventually complete with the help of a pulling force resulting from DNA condensation induced by the osmotic stress itself. This demonstrates that in vivo, the osmotically stressed cell cytoplasm will promote phage DNA ejection rather than resisting it. The further addition of DNA-binding proteins under crowding conditions is shown to enhance the extent of ejection. We also found some optimal crowding conditions for which DNA content remaining in the capsid upon ejection is maximum, which correlates well...

  11. The lateral intercellular space as osmotic coupling compartment in isotonic transport.

    Science.gov (United States)

    Larsen, E H; Willumsen, N J; Møbjerg, N; Sørensen, J N

    2009-01-01

    Solute-coupled water transport and isotonic transport are basic functions of low- and high-resistance epithelia. These functions are studied with the epithelium bathed on the two sides with physiological saline of similar composition. Hence, at transepithelial equilibrium water enters the epithelial cells from both sides, and with the reflection coefficient of tight junction being larger than that of the interspace basement membrane, all of the water leaves the epithelium through the interspace basement membrane. The common design of transporting epithelia leads to the theory that an osmotic coupling of water absorption to ion flow is energized by lateral Na(+)/K(+) pumps. We show that the theory accounts quantitatively for steady- and time dependent states of solute-coupled fluid uptake by toad skin epithelium. Our experimental results exclude definitively three alternative theories of epithelial solute-water coupling: stoichiometric coupling at the molecular level by transport proteins like SGLT1, electro-osmosis and a 'junctional fluid transfer mechanism'. Convection-diffusion out of the lateral space constitutes the fundamental problem of isotonic transport by making the emerging fluid hypertonic relative to the fluid in the lateral intercellular space. In the Na(+) recirculation theory the 'surplus of solutes' is returned to the lateral space via the cells energized by the lateral Na(+)/K(+) pumps. We show that this theory accounts quantitatively for isotonic and hypotonic transport at transepithelial osmotic equilibrium as observed in toad skin epithelium in vitro. Our conclusions are further developed for discussing their application to solute-solvent coupling in other vertebrate epithelia such as small intestine, proximal tubule of glomerular kidney and gallbladder. Evidence is discussed that the Na(+) recirculation theory is not irreconcilable with the wide range of metabolic cost of Na(+) transport observed in fluid-transporting epithelia. PMID:18983444

  12. Experimental Support for a Predictive Osmotic Model of Clay Membranes

    International Nuclear Information System (INIS)

    Osmosis has been cited as a mechanism for explaining anomalously high fluid pressures in the subsurface. Clays and shales act as membranes, and osmotic flux across these units may result in pressures sufficiently high to explain these anomalies. The theoretical osmotic pressures as calculated solely from solution properties can be quite large; however, it is not yet resolved whether these geologic membranes are sufficiently ideal to generate such pressures

  13. Osmotic fragility test in heterozygotes for alpha and beta thalassaemia.

    OpenAIRE

    Maccioni, L; Cao, A

    1985-01-01

    This study shows that the combination of heterozygous beta thalassaemia and deletion heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) alpha+ thalassaemia may result in the production of erythrocytes which have normal mean volume and haemoglobinisation but decreased osmotic fragility. Based on this finding and previous studies, which have shown that beta thalassaemia screening by the osmotic fragility test may miss a significant proportion of beta thalassaemia heterozygotes, we ...

  14. Osmotic Pressure and Packaging Structure of Caged DNA☆

    OpenAIRE

    Li, Zhidong; Wu, Jianzhong; Wang, Zhen-Gang

    2008-01-01

    We present a theoretical model for aqueous solutions of double-stranded (ds) DNA with explicit consideration of electrostatic interactions, excluded-volume effects, van der Waals attractions, and salt ions. With reasonable parameters estimated from the DNA structure and experimental data for electrolytes, we are able to reproduce the DNA osmotic pressure in the bulk in good agreement with experiment. The predicted DNA osmotic pressure in λ-bacteriophages is found to coincide with that of the ...

  15. Physiological and genetic responses of bacteria to osmotic stress.

    OpenAIRE

    Csonka, L N

    1989-01-01

    The capacity of organisms to respond to fluctuations in their osmotic environments is an important physiological process that determines their abilities to thrive in a variety of habitats. The primary response of bacteria to exposure to a high osmotic environment is the accumulation of certain solutes, K+, glutamate, trehalose, proline, and glycinebetaine, at concentrations that are proportional to the osmolarity of the medium. The supposed function of these solutes is to maintain the osmolar...

  16. Electro-chemical sensors, sensor arrays and circuits

    Science.gov (United States)

    Katz, Howard E.; Kong, Hoyoul

    2014-07-08

    An electro-chemical sensor includes a first electrode, a second electrode spaced apart from the first electrode, and a semiconductor channel in electrical contact with the first and second electrodes. The semiconductor channel includes a trapping material. The trapping material reduces an ability of the semiconductor channel to conduct a current of charge carriers by trapping at least some of the charge carriers to localized regions within the semiconductor channel. The semiconductor channel includes at least a portion configured to be exposed to an analyte to be detected, and the trapping material, when exposed to the analyte, interacts with the analyte so as to at least partially restore the ability of the semiconductor channel to conduct the current of charge carriers.

  17. Enteric bacteria and osmotic stress: intracellular potassium glutamate as a secondary signal of osmotic stress?

    Science.gov (United States)

    Booth, I R; Higgins, C F

    1990-06-01

    Enteric bacteria have evolved an impressive array of mechanisms that allow the cell to grow at widely different external osmotic pressures. These serve two linked functions; firstly, they allow the cell to maintain a relatively constant turgor pressure which is essential for cell growth; and secondly they permit changes in cytoplasmic composition such that the accumulation of intracellular osmolytes required to restore turgor pressure does not impair enzyme function. The primary event in turgor regulation is the controlled accumulation of potassium and its counterion glutamate. At high external osmolarities the cytoplasmic levels of potassium glutamate can impair enzyme function. Rapid growth is therefore dependent upon secondary responses, principally the accumulation of compatible solutes, betaine (N-trimethylglycine), proline and trehalose. The accumulation of these solutes is achieved by the controlled activity of transport systems and enzymes in response to changes in external osmotic pressure. It has been proposed that the accumulation of potassium glutamate during turgor regulation acts as a signal for the activation of these systems [1,2]. This brief review will examine the evidence that control over the balance of cytoplasmic osmolytes is achieved by sensing of the intracellular potassium (and glutamate) concentration. PMID:1974769

  18. Coupled chemo-electro-mechanical finite element simulation of hydrogels: II. Electrical stimulation

    International Nuclear Information System (INIS)

    Certain polyelectrolyte gels are distinguished by a large swelling or bending capability under the influence of external physical, chemical or electrical stimuli. In this paper we investigate the mechanisms occurring in polyelectrolyte gels due to externally applied electric fields. By applying a coupled chemo-electro-mechanical model which is extended and predestined for electrical stimulation, we describe the concentrations and the electric potential in both the gel and the solution as well as the locally different swelling and shrinking in the gel. The local change of geometry is formulated by a local osmotic pressure difference between the gel and the solution next to the gel phase. In addition to this effect, the change of the local gel domain leads to a local variation of the concentration of bound groups and thus to a change of the local concentrations of mobile ions. As the focus of the presented work we demonstrate the superiority of the fully coupled chemo-electro-mechanical description compared to the previously developed one-way chemo-electric to mechanical coupled model. Finally, by a qualitative comparison with experimental results, the validity of the fully coupled chemo-electro-mechanical model for electrical stimulation is demonstrated

  19. Interface-tracking electro-hydrodynamic model for droplet coalescence

    Science.gov (United States)

    Crowl Erickson, Lindsay; Noble, David

    2012-11-01

    Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. micro-fluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. We present a conformal decomposition finite element (CDFEM) interface-tracking method for two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface. The electro-hydrodynamic equations solved allow for convection of charge and charge accumulation at the interface, both of which may be important factors for the pinch-off dynamics in this parameter regime.

  20. One biquaternion model of electro-gravimagnetic field. Field analogues of Newton laws

    OpenAIRE

    Alexeyeva, Lyudmila A.

    2007-01-01

    Using the biquaternions algebra with involution and mutual quaternional gradients the equations of one model of electro-gravimagnetic (EGM) field are constructed on the base of Hamilton form of Maxwell equations. For this field the hypothesis of equivalence of magnetic charge to gravitational mass is implied. The equations of interaction of generated by different charges and currents EGM-fields are built. On its base the analogies of three Newton's laws are obtained. The laws of transformatio...

  1. Uniqueness of photon spheres in electro-vacuum spacetimes

    CERN Document Server

    Cederbaum, Carla

    2015-01-01

    In a recent paper, the authors established the uniqueness of photon spheres in static vacuum asymptotically flat spacetimes by adapting Bunting and Masood-ul-Alam's proof of static vacuum black hole uniqueness. Here, we establish uniqueness of suitably defined sub-extremal photon spheres in static electro-vacuum asymptotically flat spacetimes by adapting the argument of Masood-ul-Alam. As a consequence of our result, we can rule out the existence of electrostatic configurations involving multiple "very compact" electrically charged bodies and sub-extremal black holes.

  2. Electro-Optics/Low Observables Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Electro-Optics/Low Observables Laboratory supports graduate instruction for students enrolled in the Low Observables program. Its purpose is to introduce these...

  3. Missile Electro-Optical Countermeasures Simulation Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — This laboratory comprises several hardware-in-the-loop missile flight simulations designed specifically to evaluate the effectiveness of electro-optical air defense...

  4. Electro-mechanical sensing in freestanding monolayered gold nanoparticle membranes

    Science.gov (United States)

    Gauvin, M.; Grisolia, J.; Alnasser, T.; Viallet, B.; Xie, S.; Brugger, J.; Ressier, L.

    2016-06-01

    -induced length variation of the interparticle junctions. This work thus evidences a new class of highly sensitive nano-electro-mechanical systems based on freestanding monolayered gold NP membranes. Electronic supplementary information (ESI) available: TEM images of freestanding monolayered Au NP membranes and nanoparticle size distribution, the AFM topography image and corresponding profile of an Au NP membrane, the force-displacement curve of a 5 μm wide freestanding monolayered Au NP membrane, discussion on the charging energy model for Arrhenius type temperature dependence, details of the numerical simulations of strain-induced resistance variations in freestanding NP membranes and mappings of the simulated normalized current and local strain in a 5 μm wide polarized NP membrane under point-load actuation. See DOI: 10.1039/c6nr02004f

  5. Electro-expulsive separation system

    Science.gov (United States)

    Haslim, Leonard A. (Inventor); Lee, Robert D. (Inventor)

    1987-01-01

    An electro-expulsive system has one or more overlapped conductors, each comprising a flexible ribbon conductor, which is folded back on itself. The conductors are embedded in an elastomeric material. Large current pulses are fed to the conductors from power storage units. As a result of the antiparallel currents, the opposed segments of a conductor are forcefully separated and the elastomeric material is distended. Voids in the elastomer aid the separation of the conductor segments. The distention is almost instantaneous when a current pulse reaches the conductor and the distention tends to remove any solid body on the surface of the elastomeric material.

  6. Studies of Protein Solution Properties Using Osmotic Pressure Measurements

    Science.gov (United States)

    Agena, S.; Bogle, David; Pusey, Marc; Agena, S.

    1998-01-01

    Examination of the protein crystallization process involves investigation of the liquid and solid state and a protein's properties in these states. Liquid state studies such as protein self association in solution by light scattering methods or other methods have been used to examine a protein Is properties and therefore its crystallization process and conditions. Likewise can osmotic pressure data be used to examine protein properties and various published osmotic pressure studies were examined by us to correlate osmotic pressure to protein solution properties. The solution behavior of serum albumin, alpha - chymotrypsin, beta - lactoglobulin and ovalbumin was examined over a range of temperatures, pH values and different salt types and concentrations. Using virial expansion and a local composition model the non ideal solution behavior in form of the activity coefficients (thermodynamic) was described for the systems. This protein activity coefficient data was related to a protein's solubility behavior and this process and the results will be presented.

  7. Repulsion between oppositely charged planar macroions.

    Directory of Open Access Journals (Sweden)

    YongSeok Jho

    Full Text Available The repulsive interaction between oppositely charged macroions is investigated using Grand Canonical Monte Carlo simulations of an unrestricted primitive model, including the effect of inhomogeneous surface charge and its density, the depth of surface charge, the cation size, and the dielectric permittivity of solvent and macroions, and their contrast. The origin of the repulsion is a combination of osmotic pressure and ionic screening resulting from excess salt between the macroions. The excess charge over-reduces the electrostatic attraction between macroions and raises the entropic repulsion. The magnitude of the repulsion increases when the dielectric constant of the solvent is lowered (below that of water and/or the surface charge density is increased, in good agreement with experiment. Smaller size of surface charge and the cation, their discreteness and mobility are other factors that enhance the repulsion and charge inversion phenomenons.

  8. Coulomb field strength measurement by electro-optic spectral decoding system at the CALIFES beam line

    CERN Document Server

    Pan, R; Lefevre, T; Gillepsie, WA; CERN. Geneva. ATS Department

    2015-01-01

    Electro-optic (EO) techniques are increasingly used for longitudinal bunch profile measurements. A bunch profile monitor, based on electro-optic spectral decoding(EOSD), has been developed and demonstrated on the CALIFES beam line at CERN. The EO response is analysed using a frequency domain description, and two methods for extraction of absolute Coulomb field strengths from the electron bunch are demonstrated. Measurements at field strengths up to 1.3 MV/m agree with the expectation based on independent charge measurements.

  9. Coulomb field strength measurement by electro-optic spectral decoding system at the CALIFES beam line

    Science.gov (United States)

    Pan, R.; Jamison, S. P.; Lefevre, T.; Gillespie, W. A.

    2016-06-01

    Electro-optic (EO) techniques are increasingly used for longitudinal bunch profile measurements. A bunch profile monitor, based on electro-optic spectral decoding (EOSD), has been developed and demonstrated on the CALIFES beam line at CERN. The EO response is analysed using a frequency domain description, and two methods for extraction of absolute Coulomb field strengths from the electron bunch are demonstrated. Measurements at field strengths up to 1.3 MV/m agree with the expectation based on independent charge measurements.

  10. Linear electro-optical properties of tetragonal BaTiO3

    Indian Academy of Sciences (India)

    P U Sastry

    2002-09-01

    Linear optical susceptibility and clamped linear electro-optical tensor coefficients of tetragonal BaTiO3 are calculated using a formalism based on bond charge theory. Calculated values are in close agreement with experimental data. The covalent Ti–O bonds constituting distorted TiO6 octahedral groups are found to be major contributors to the electro-optic coefficients making them more sensitive than the BaO12 groups for these properties. Orientations of chemical bonds play an important role in determining these properties.

  11. Identification of calmodulin released by osmotic shock of maize roots

    International Nuclear Information System (INIS)

    Exogenously applied calcium at low concentrations (10 mM and less) stimulates, while higher concentrations (greater than 20 mM) inhibit maize root growth. The phenothiazine calmodulin inhibitors chlorpromazine and trifluoperzine inhibit maize root growth and are reversible by calcium. The loss of acid-inducible growth after osmotic shock indicates that at least part of the complex associated the acid-induced growth is released. Since calmodulin (CaM) is a small protein (mol wt about 17 kD) found to play a pivotal role in Ca+2 regulated mechanisms, the material released from maize roots by osmotic shock was examined for the presence of CaM

  12. A. P. S. ELECTRO-TUBE EVALUATION

    Science.gov (United States)

    The report gives results of an evaluation of an Air Pollution Systems (APS) Inc. Electro-Tube, a wet electrostatic precipitator. Fine particle collection efficiency as a function of particle size was computed from data taken on the Electro-Tube. It was operated at gas flow rates ...

  13. Dielectric sample with two-layer charge distribution for space charge calibration purposes

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Rasmussen, C.

    2002-01-01

    In the present paper is described a dielectric test sample with two very narrow concentrations of bulk charges, achieved by two internal electrodes not affecting the acoustical properties of the sample, a fact important for optimal application of most space charge measuring systems. Space charge...... formation was investigated under different electrical conditions by means of the laser induced pressure pulse (LIPP) method and the pulsed electro-acoustic method (PEA)....

  14. The Criteria for Interfacial Electro-Thermal Equilibrium

    CERN Document Server

    Seaver, Albert E

    2008-01-01

    When the surface of a first material is brought into contact with the surface of a second material the contact region is called an interface. Since the time of James Clerk Maxwell it has been customary to treat a material electrically as having well-defined bulk properties and having surfaces of zero-thickness. In order to obtain a better understanding of the interface this paper reviews Maxwell's original argument to justify a zero-thickness-surface and reexamines the interface problem assuming electrical charges are actually particles having a finite thickness. Thermodynamics requires that in thermal equilibrium any movement of free charge cannot produce a net electrical current anywhere in the materials or across their interface. For materials in contact and in thermal equilibrium this reexamination gives a set of equations that can be called the interfacial electro-thermal equilibrium (IETE) criteria. A well-defined interfacial potential results from this criteria.

  15. Electro-acoustic shock waves in dusty plasmas

    International Nuclear Information System (INIS)

    A rigorous theoretical investigation has been made of electro- acoustic [particularly, dust-ion acoustic (DIA) and dust-acoustic (DA)] shock waves in unmagnetized dusty plasmas. The reductive perturbation method has been employed for the study of the small but finite amplitude DIA and DA shock waves. It has been reported that the dust grain charge fluctuation can be one of the candidates for the source of dissipation, and can be responsible for the formation of DIA shock waves in an unmagnetized dusty plasma with static charged dust particles. It has also been reported that the strong co-relation among dust particles can be one of the candidates for the source of dissipation, and can be responsible for the formation of DA shock waves in an unmagnetized strongly coupled dusty plasma. The basic features and the underlying physics of DIA and DA shock waves, which are relevant to space and laboratory dusty plasmas, are briefly discussed. (author)

  16. Electro-magnetically controlled acoustic metamaterials with adaptive properties.

    Science.gov (United States)

    Malinovsky, Vladimir S; Donskoy, Dimitri M

    2012-10-01

    A design of actively controlled metamaterial is proposed and discussed. The metamaterial consists of layers of electrically charged nano or micro particles exposed to external magnetic field. The particles are also attached to compliant layers in a way that the designed structure exhibits two resonances: mechanical spring-mass resonance and electro-magnetic cyclotron resonance. It is shown that if the cyclotron frequency is greater than the mechanical resonance frequency, the designed structure could be highly attenuative (40-60 dB) for vibration and sound waves in very broad frequency range even for wavelength much greater than the thickness of the metamaterial. The approach opens up wide range of opportunities for design of adaptively controlled acoustic metamaterials by controlling magnetic field and/or electrical charges. PMID:23039553

  17. Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

    OpenAIRE

    Kowalski Stefan J.; Łechtańska Joanna M.

    2015-01-01

    This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L.) after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl) concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG), Water Loss (WL), Weight Reduction (WR) were determined. It...

  18. Microbial fuel cells and osmotic membrane bioreactors have mutual benefits for wastewater treatment and energy production.

    Science.gov (United States)

    Hou, Dianxun; Lu, Lu; Ren, Zhiyong Jason

    2016-07-01

    This study demonstrates that microbial fuel cells (MFCs) and osmotic membrane bioreactors (OMBRs) can be mutually beneficial when integrated together for wastewater treatment. When connecting MFCs with OMBRs, the solute buildup increased conductivity and buffer capacity, which greatly increased MFC power density from 3 W/m(3) up to 11.5 W/m(3). In turn, the MFCs conditioned and reduced sludge production and therefore reduced forward osmosis (FO) membrane fouling. The MFC-OMBR equipped with new thin-film composite (TFC) membrane showed excellent organic (>95%) and phosphorus removal (>99%) and therefore maintained effluent sCOD below 20 mg/L. However, the nitrogen removal was limited due to the negative surface charge of the thin-film composite membrane and solution chemistry, which led to higher flux of ammonium toward the OMBR draw solution. Further studies are needed to improve nitrogen removal, reduce fouling, and optimize system integration. PMID:27105032

  19. Osmotic dehydration of mandarins: Influence of reutilized osmotic agent on behaviour and product quality

    Directory of Open Access Journals (Sweden)

    Maria Lobo Sapata

    2009-09-01

    Full Text Available   Background. Osmotic dehydration (OD is a technology that allows the concentration mainly of fruits and vegetables, without change of phase, through partial water removal, when immersed in a hypertonic solution of sugar, salt or others. It can be successfully applied to some products whose production is not fully marketed in fresh form. However, an additional process is necessary to stabilize the product. The process leads to the achievement of high quality alternative products, with an extended shelf-life, economy in storage and transport. The aim of this work was to study, at a pilot scale, the behaviour evaluation of a sucrose dehydration solution, during twelve OD reuses, and the quality of processed mandarins. Material and methods. The process was carried out using mandarins (Citrus reticulata Blanco cv Clementina Nova, from Algarve, Portugal, manually peeled and segments chemically skinned. In assays a 60°Brix sucrose solution was used, conducted in thermo- -stabilized baths, at 45°C, 16 h, 40 oscillations per minute and a fruit:solution ratio of 1:2 (m/m. After each OD cycle, the solution was filtered and reconcentred to 60°Brix by sucrose addition, and adjusted to original volume. The osmodehydrated mandarins were stabilized by pasteurization. The drying solution behaviour and mandarins’ quality were assessed through different physical, chemical and microbiological analysis. Results. The factorial discriminate analysis allowed to distinguish a different behaviour between the original and final dehydration sucrose solution during OD processes, but did not affect its desiccant power, only a high pollutant load development explained by BOD5 values. The results of osmodehydrated mandarins showed that stability was achieved by “combined process” with pasteurization. Conclusions. The resultslead to concludethat osmotic dehydration process is a good option to improve mandarin’s stabilization, after pasteurization

  20. A Simple Membrane Osmometer System & Experiments that Quantitatively Measure Osmotic Pressure

    Science.gov (United States)

    Marvel, Stephen C.; Kepler, Megan V.

    2009-01-01

    It is important for students to be exposed to the concept of osmotic pressure. Understanding this concept lays the foundation for deeper discussions that lead to more theoretical aspects of water movement associated with the concepts of free energy, water potential, osmotic potential, pressure potential, and osmotic adjustment. The concept of…

  1. Electro-smog; Elektrosmog. Ein Thema in aller Munde, doch viele Quellen sind wenig bekannt

    Energy Technology Data Exchange (ETDEWEB)

    Thalmann, K. [Ecosens AG, Wallisellen (Switzerland); Gugler, M. [Schaffner EMV AG, Luterbach (Switzerland)

    2007-07-01

    This article deals with the topic of electro-smog - the non-ionising radiation produced by technical installations in low and high-frequency ranges. Various sources such as mobile telephones, radio and television and newer sources such as WLAN and Bluetooth are discussed. The correct installation of electrical circuits in buildings is considered as being a simple and effective means of reducing mains-frequency electro-smog. Effects on human beings are discussed and regulations concerning protection against non-ionising radiation are examined. The fact that certain electrical and magnetic fields such as those caused by cookers, vacuum cleaners and hair-dryers are short term, whereas radio-alarms, laptops and charging stations are quasi-continuous sources. Also the placing of boilers and refrigerators is considered. The specific absorption rate (SAR) value for mobile telephones is also looked at and recommendations are made on keeping distance to electro-magnetic sources.

  2. Experimental study on electro-jet instability of coal water slurry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, J.; Zhang, J.; Luo, T.; Liu, X.; Pan, Y. [Jiangsu University, Zhenjiang (China)

    2007-04-15

    An experimental study was performed on the electro-jet instability of coal slurry (CWS) under needle-ring electrode configuration. By testing the jet divarications, splay angle of branch jets and diameter of droplets, the influence of working parameters on electron-jet instability and distribution of droplet diameters at various instability modes were analyzed. The result shows the atomisation quality of CWS electro-jet is greatly better than nonelectro-jet. Compared with the low viscous liquids, the viscosity, charging voltage and flow rate are the three most influential factors affecting highly viscous electro-jet instability. The distribution of droplet size show uni-modal and bimodal characteristics at cone jet and vibrative multi-branch jet modes respectively. 9 refs., 5 figs., 1 tab.

  3. Osmotic generation of 'anomalous' fluid pressures in geological environments

    Science.gov (United States)

    Neuzii, C.E.

    2000-01-01

    Osmotic pressures are generated by differences in chemical potential of a solution across a membrane. But whether osmosis can have a significant effect on the pressure of fluids in geological environments has been controversial, because the membrane properties of geological media are poorly understood. 'Anomalous' pressures - large departures from hydrostatic pressure that are not explicable in terms of topographic or fluid-density effects are widely found in geological settings, and are commonly considered to result from processes that alter the pore or fluid volume, which in turn implies crustal changes happening at a rate too slow to observe directly. Yet if osmosis can explain some anomalies, there is no need to invoke such dynamic geological processes in those cases. Here I report results of a nine- year in situ measurement of fluid pressures and solute concentrations in shale that are consistent with the generation of large (up to 20 MPa) osmotic-pressure anomalies which could persist for tens of millions of years. Osmotic pressures of this magnitude and duration can explain many of the pressure anomalies observed in geological settings. The require, however, small shale porosity and large contrasts in the amount of dissolved solids in the pore waters - criteria that may help to distinguish between osmotic and crystal-dynamic origins of anomalous pressures.

  4. Osmotic pressure of the cutaneous surface fluid of Rana esculenta

    DEFF Research Database (Denmark)

    Hviid Larsen, Erik; Ramløv, Hans

    /Kg, n = 16. Osmolality of lymph was, 239 ± 4 mosmol/Kg, n = 8. Thus the flow of water across the epidermis would be in the direction from CSF to the interstitial fluid driven by the above osmotic gradients and/or coupled to the inward active Na+ flux via the slightly hyperosmotic paracellular...

  5. Mass Transfer During Osmotic Dehydration Using Acoustic Cavitation

    Institute of Scientific and Technical Information of China (English)

    孙宝芝; 淮秀兰; 姜任秋; 刘登瀛

    2005-01-01

    An experimental study on intensifying osmotic dehydration was carried out in a state of nature and with acoustic cavitation of different cavitating intensity (0.5A, 0.TA and 0.9A) respectively, in which the material is apple slice of 5 mm thickness. The result showed that acoustic cavitation remarkably enhanced the osmotic dehydration, and the water loss was accelerated with the increase of cavitating intensity. The water diffusivity coefficients ranged from 1.8 × 10-10 m2.s-1 at 0.5A to 2.6 × 10-10 m2.s-1 at 0.9A, and solute diffusivity coefficients ranged from 3.5×10-11 m2.s-1 at 0.5A to 4.6×10-11 m2.s-1 at 0.9A. On the basis of experiments, a mathematical model was established about mass transfer during osmotic dehydration, and the numerical simulation was carried out. The calculated results agree well with experimental data, and represent the rule of mass transfer during osmotic dehydration intensified by acoustic cavitation.

  6. An Overview on Osmotic Controlled Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Thummar A

    2013-06-01

    Full Text Available This paper reviews constructed drug delivery systems applying osmotic principles for controlled drugrelease from the formulation. Osmotic devices which are tablets coated with walls of controlled porosityare the most promising strategy based systems for controlled drug delivery. In contrast to commontablets, these pumps provide constant (zero order drug release rate. When these systems are exposed towater, low levels of water soluble additive is leached from polymeric material i.e. semipermeablemembrane and drug releases in a controlled manner over an extended period of time. The main clinicalbenefits of oral osmotic drug delivery system are their ability to improve treatment tolerability andpatient compliance. These advantages are mainly driven by the capacity to deliver drugs in a sustainedmanner, independent of the drug chemical properties, of the patient’s physiological factors or followingfood intake. This review brings out the theoretical concept of drug delivery, history, advantages anddisadvantages of the delivery systems, types of oral osmotic drug delivery systems, factors affecting thedrug delivery system and marketed products.

  7. Root water extraction under combined water and osmotic stress

    NARCIS (Netherlands)

    Jong van Lier, de Q.; Dam, van J.C.; Metselaar, K.

    2009-01-01

    Using a numerical implicit model for root water extraction by a single root in a symmetric radial flow problem, based on the Richards equation and the combined convection-dispersion equation, we investigated some aspects of the response of root water uptake to combined water and osmotic stress. The

  8. Vocal Fold Epithelial Response to Luminal Osmotic Perturbation

    Science.gov (United States)

    Sivasankar, Mahalakshmi; Fisher, Kimberly V.

    2007-01-01

    Purpose: Dry-air challenges increase the osmolarity of fluid lining the luminal surface of the proximal airway. The homeostasis of surface fluid is thought to be essential for voice production and laryngeal defense. Therefore, the authors hypothesized that viable vocal fold epithelium would generate a water flux to reduce an osmotic challenge (150…

  9. Osmotic Stressing, Membrane Leakage, and Fluorescence: An Introductory Biochemistry Demonstration

    Science.gov (United States)

    Seu, Kalani J.

    2015-01-01

    A fluorescence demonstration is described that incorporates several fundamental aspects of an introductory biochemistry course. A variation of a known leakage assay is utilized to prepare vesicles containing a quenched fluorophore. The vesicles are exposed to several osmotic environments ranging from isotonic to hypotonic. The degree of vesicle…

  10. A semi-automatic device for measuring osmotic pressures (1962)

    International Nuclear Information System (INIS)

    A cryoscopic apparatus for measuring osmotic pressure in small samples (0.1 ml) is described. The sample is frozen by air cooled dry ice or liquid nitrogen; the temperature is measured by a thermistor resistance and a recording millivoltmeter. (author)

  11. Self-consistent unstirred layers in osmotically driven flows

    DEFF Research Database (Denmark)

    Jensen, Kåre Hartvig; Bohr, Tomas; Bruus, Henrik

    2010-01-01

    on both sides of the membrane remain well mixed due to an external stirring mechanism. We investigate the effects of concentration boundary layers on the efficiency of osmotic pumping processes in the absence of external stirring, i.e. when all advection is provided by the osmosis itself. This case...

  12. Controlled porosity solubility modulated osmotic pump tablets of gliclazide.

    Science.gov (United States)

    Banerjee, Arti; Verma, P R P; Gore, Subhash

    2015-06-01

    A system that can deliver drug at a controlled rate is very important for the treatment of various chronic diseases such as diabetes, asthma, and heart disease. Poorly water-soluble drug with pH-dependent solubility such as gliclazide (GLZ) offers challenges in the controlled-release formulation because of low dissolution rate and poor bioavailability. Solid dispersion (SD) of GLZ consisted of hydroxypropyl cellulose (HPC-SSL) as a polymeric solubilizer was manufactured by hot melt extrusion (HME) technology. Then, controlled porosity osmotic pump (CPOP) tablet of gliclazide was designed to deliver drug in a controlled manner up to 16 h. The developed formulation was optimized for type and level of pore former and coating weight gain. The optimized formulation was found to exhibit zero order kinetics independent of pH and agitation speed but depends on osmotic pressure of dissolution media indicated that mechanism of drug release was osmotic pressure. The in vivo performance prediction of developed formulation using convolution approach revealed that the developed formulation was superior to the existing marketed extended-release formulation in terms of attaining steady state plasma levels and indicated adequate exposure in translating hypoglycemic response. The prototype solubilization method combined with controlled porosity osmotic pump based technique could provide a unique way to increase dissolution rate and bioavailability of many poorly water-soluble, narrow therapeutic index drugs used in diabetes, cardiovascular diseases, etc. PMID:25378281

  13. Micro electro-mechanical heater

    Science.gov (United States)

    Oh, Yunje; Asif, Syed Amanulla Syed; Cyrankowski, Edward; Warren, Oden Lee

    2016-04-19

    A sub-micron scale property testing apparatus including a test subject holder and heating assembly. The assembly includes a holder base configured to couple with a sub-micron mechanical testing instrument and electro-mechanical transducer assembly. The assembly further includes a test subject stage coupled with the holder base. The test subject stage is thermally isolated from the holder base. The test subject stage includes a stage subject surface configured to receive a test subject, and a stage plate bracing the stage subject surface. The stage plate is under the stage subject surface. The test subject stage further includes a heating element adjacent to the stage subject surface, the heating element is configured to generate heat at the stage subject surface.

  14. Electro-optic modulator material

    Science.gov (United States)

    Adams, John J.; Ebbers, Chris A.

    2005-02-22

    An electro-optic device for use with a laser beam. A crystal has a first face and a second face. Means are provided for applying a voltage across the crystal to obtain a net phase retardation on the polarization of the laser beam when the laser beam is passed through the crystal. In one embodiment the crystal is composed of a compound having the chemical formula ReAe40(BO3)3 where: RE consists of one or more of the following elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and two other elements Y and Sc; and where Ae is from the list of Ca, Sr, or Ba.

  15. Electro optical monitor final report

    CERN Document Server

    Dehler, M

    2013-01-01

    In the CLIC two beam acceleration scheme the Main Beam must be precisely synchronized with respect to the RF power produced by the Drive Beam. Timing errors would have an impact on the collider performances. The Drive Beam phase errors should be controlled, by means of a feed forward system, within 0.1 ° (23 fs @ 12GHz) to avoid a luminosity reduction larger than 2%. A beam phase arrival monitor is an essential component of the system. As an alternative to a classical design using analogue electronic done in task 9.5.1., we pursue an approach using electro optical modulators. The advantage of this is its very high band width, it is measuring the arrival time of individual bunches with a potential resolution below 10 fs. The system was designed, manufactured and tested. As specified in the work package, the performance with beam was validated at the PSI injector.

  16. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    International Nuclear Information System (INIS)

    Highlights: • We report a facile method for fabrication of MnO2 nanostructures on electro-etched carbon fiber. • MnO2-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO2-ECF electrode. • The coulombic efficiency of MnO2-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO2 on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO2 electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g−1 was achieved at a scan rate of 5 mV s−1 for MnO2 electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes

  17. Electrodeposited manganese dioxide nanostructures on electro-etched carbon fibers: High performance materials for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Kazemi, Sayed Habib, E-mail: habibkazemi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Maghami, Mostafa Ghaem [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kiani, Mohammad Ali [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of)

    2014-12-15

    Highlights: • We report a facile method for fabrication of MnO{sub 2} nanostructures on electro-etched carbon fiber. • MnO{sub 2}-ECF electrode shows outstanding supercapacitive behavior even at high discharge rates. • Exceptional cycle stability was achieved for MnO{sub 2}-ECF electrode. • The coulombic efficiency of MnO{sub 2}-ECF electrode is nearly 100%. - Abstract: In this article we introduce a facile, low cost and additive/template free method to fabricate high-rate electrochemical capacitors. Manganese oxide nanostructures were electrodeposited on electro-etched carbon fiber substrate by applying a constant anodic current. Nanostructured MnO{sub 2} on electro-etched carbon fiber was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis. The electrochemical behavior of MnO{sub 2} electro-etched carbon fiber electrode was investigated by electrochemical techniques including cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. A maximum specific capacitance of 728.5 F g{sup −1} was achieved at a scan rate of 5 mV s{sup −1} for MnO{sub 2} electro-etched carbon fiber electrode. Also, this electrode showed exceptional cycle stability, suggesting that it can be considered as a good candidate for supercapacitor electrodes.

  18. Electro-optical effects and temperature-dependent electrical properties of LuFe2O4 thin films

    International Nuclear Information System (INIS)

    We report electro-optical and temperature-dependent electrical-transport properties of LuFe2O4 (LFO) thin films. The LFO thin films at 78 K showed the electro-optical effects of size up to 5% near the Fe2+d to d on-site electronic transition. In the three-dimensional charge-ordered state of LFO, we observed hysteresis in dc voltage–current measurements and nonlinear voltage–current relationship in transient response of voltage under current pulses. The electro-optical and electrical properties of LFO thin films are interpreted in terms of the field-induced changes of the charge-ordered state mediated by the spin–charge–lattice coupling effect. We also discuss possible mechanisms of the complex electrical properties and electro-optical effects in conjunction with the Maxwell–Wagner effects. - Highlights: • High quality thin films of LuFe2O4 on sapphire substrates by e-beam deposition • Electro-optical effects up to 5% near the Fe d to d electronic transition at 78 K • Hysteresis effects in dc voltage–current and nonlinear response in ac voltage–current • Field-induced changes of the CO state mediated by the spin-charge-lattice

  19. Electro-optic properties of organic nanotubes.

    Science.gov (United States)

    Stoylov, Stoyl P; Stoilova-McPhie, Svetla

    2011-08-10

    In this review article the theoretical and experimental possibilities of applying EO-methods for estimation of the physico-chemical properties of the organic nanotubes (ONTs) are studied. The ONTs are highly organized nanostructures of strongly elongated, anysometric, and hollow cylinders with a size range of 1 nm to 10,000 nm, e.g. in aqueous solutions they could behave as colloid (disperse) particles. They have high interaction ability due to their extremely large curved, rolled-up external surfaces (bilayers of membrane walls) and unique properties because of their specific electric charge distribution and dynamics that make possible the functionalization of their surfaces. Thus they could template guestsubstances such as membrane proteins and protein complexes on the exterior surfaces and in the membrane. We performed our investigations for the case of ONT aqueous colloid suspension. Following our earlier proposition of the general expression for the electro-optic (EO) effect we derived equations for the evaluation of the electric properties of ONT particles such as mechanism of electric polarization and identification of their most important electric Dipole Moments (DM), permanent (pDM) and induced (iDMs). Further we recommend ways for the calculation of their magnitude and direction. Also we evaluated some geometrical properties such as length of the ONT particles and their polydispersity. The knowledge that we provided about the ONT properties may enable us to elucidate and predict their biological activity. Templating biological active ligands (such as membrane proteins and protein complexes) on the inner and outer surfaces as well as in the surface membrane creates their potential usefulness as carrier and deliverer of biopharmaceuticals in bio-nanodevices. The theoretical equations were compared with the experimental data for ONTs such as (lipid) LNT, Tobacco Mosaic Virus (TMV) and microtubules (MT). Comparison of EO methods with other methods used till

  20. Drying of red beetroot after osmotic pretreatment: Kinetics and quality considerations

    Directory of Open Access Journals (Sweden)

    Kowalski Stefan J.

    2015-09-01

    Full Text Available This article presents experimental studies on drying kinetics and quality effects of red beetroot (Beta vulgaris L. after convective drying with a preliminary osmotic pretreatment. The effects of the osmotic agent (NaCl concentration and the osmotic bath time on the product colour and nutrient content preservation, the water activity, and rehydration ability after drying were analysed. Osmotic dehydration curves and Solid Gain (SG, Water Loss (WL, Weight Reduction (WR were determined. It was proved that drying of beetroot with osmotic pretreatment contributes to shorter drying time, smaller water activity, higher retention of betanin, better colour preservation, and a greater degree of water resorption.

  1. Charged spin-1 gluons, parton model and the Archimedes effect

    International Nuclear Information System (INIS)

    In a gauge theory of (SU(2) x U(1))sub(flavour) x SU(3)sub(colour) with unconfined integer-charged quarks and massive inter-charged gluons both quarks and gluons contribute to electro and neutrino-production. The gluon parton contribution to the lepto-production of colour is considered. (author)

  2. Treatment of Sprain by Electro-Acupuncture

    Institute of Scientific and Technical Information of China (English)

    郭乃琴

    2003-01-01

    @@ Sprain is a injury commonly encountered in the daily life and sports event. Since 1998, I have treated such cases by electro-acupuncture with satisfactory results. The following is a brief summary.

  3. Electro Polishing of Niobium Cavities at DESY

    CERN Document Server

    Matheisen, A; Morales, H; Petersen, B; Schmoekel, M; Steinhau-Kühl, N

    2004-01-01

    At DESY a facility for electro polishing (EP) of the super conducting (s.c.) TESLA/TTF cavities have been built and is operational since summer 2003. The EP infrastructure is capable to handle single-cell structures and the standard TESLA/ TTF nine-cell cavities. Several electro polishing processes have been made since and acceleration voltage up to 40 MV/m have been reached in nine cell structures. We report on measurements and experiences gained since 2003 as well as on handling procedures developed for the preparation of electro polished resonators. Specific data like heat production, variation of current density and bath aging will be presented. Another important point for reproducible results is the quality control of the electro polishing process. First quality control steps to be implanted in the EP procedure for large-scale production will be described.

  4. Fiber Acousto-Electro-Optic Modulator

    Institute of Scientific and Technical Information of China (English)

    Anen; Jiang

    2003-01-01

    A new kind of fiber acousto-electro-optic modulator is made by using Lithium Niobate crystal. This kind of modulator can be used in fiber communication, and its center frequency can be changed by directed current voltages.

  5. Precision Munition Electro-Sciences Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility allows the characterization of the electro-magnetic environment produced by a precision weapon in free flight. It can measure the radiofrequency (RF)...

  6. Design of an osmotic pressure sensor for sensing an osmotically active substance

    Science.gov (United States)

    Ch, Nagesh; Paily, Roy P.

    2015-04-01

    A pressure sensor based on the osmosis principle has been designed and demonstrated successfully for the sensing of the concentration levels of an osmotically active substance. The device is fabricated using the bulk micro-machining technique on a silicon on insulator (SOI) substrate. The substrate has a square cavity on the bottom side to fill with the reference glucose solution and a silicon (Si) membrane on the top side for the actuation. Two sets of devices, having membrane thicknesses of 10 µm and 25 µm, but the same area of 3 mm ×3 mm, are fabricated. The cavity is filled with a glucose solution of 100 mg dL-1 and it is sealed with a semi-permeable membrane made up of cellulose acetate material. The glucose solution is employed to prove the functionality of the device and it is tested for different glucose concentration levels, ranging from 50 mg dL-1 to 450 mg dL-1. The output voltage obtained for the corresponding glucose concentration levels ranges from -6.7 mV to 22.7 mV for the 10 µm device and from -1.7 mV to 4 mV for the 25 µm device. The device operation was simulated using the finite element method (FEM) and the finite volume method (FVM), and the simulation and experimental results match closely. A response time of 40 min is obtained in the case of the 10 µm device compared to one of 30 min for the 25 µm device. The response times obtained for these devices are found to be small compared to those in similar works based on the osmosis principle. This pressure sensor has the potential to provide controlled drug delivery if it can be integrated with other microfluidic devices.

  7. Electro-optic component mounting device

    Science.gov (United States)

    Gruchalla, Michael E.

    1994-01-01

    A technique is provided for integrally mounting a device such as an electro-optic device (50) in a transmission line to avoid series resonant effects. A center conductor (52) of the transmission line has an aperture (58) formed therein for receiving the device (50). The aperture (58) splits the center conductor into two parallel sections on opposite sides of the device. For a waveguide application, the center conductor is surrounded by a conductive ground surface (54), which is spaced apart from the center conductor with a dielectric material (56). One set of electrodes formed on the surface of the electro-optic device (50) is directly connected to the center conductor 52 and an electrode formed on the surface of the electro-optic device is directly connected to the conductive ground surface (54). The electrodes formed on the surface of the electro-optic device are formed on curved sections of the surface of the device to mate with correspondingly shaped electrodes on the conductor and ground surface to provide a uniform electric field across the electro-optic device. The center conductor includes a passage ( 60) formed therein for passage of optical signals to an electro-optic device.

  8. Coupled chemo-electro-mechanical finite element simulation of hydrogels: I. Chemical stimulation

    International Nuclear Information System (INIS)

    Polyelectrolyte gels are viscoelastic adaptive materials with enormous swelling capabilities under the influence of different kinds of stimulation, e.g. chemical, electrical or thermal. This unique property makes them very attractive for 'pseudomuscular' actuators. In this paper we investigate the mechanism of the chemical stimulation, by changing the salt concentration in the solution bath surrounding the gel. By applying a fully coupled chemo-electro-mechanical model, the change of the concentrations, of the electric potential and of the displacement are investigated when varying the ambient chemical conditions. The change of the mechanical displacement and the gel geometry is realized by the change of the osmotic pressure difference between the gel and the solution. The volume change of the gel leads to a change in the concentration of bound anionic groups while keeping their mole number constant. It is shown that the full coupling of the mechanical and the chemo-electrical field is necessary and that it is a real improvement to the previously developed one-way chemo-electric to mechanical coupling. It is demonstrated that the fully coupled model works as a kind of limiter for the change of the chemo-electric unknowns and thus for the gel deformation. A qualitative comparison with experimental results shows the validity of the fully coupled chemo-electro-mechanical model for chemical stimulation

  9. Molecular views of surface driven transport : electro-osmosis, diffusio-osmosis, and beyond

    Science.gov (United States)

    Bocquet, Lyderic; Ybert, Christophe; Ajdari, Armand

    2006-11-01

    We investigate the molecular mechanisms associated with surface driven transport, such as electro-, diffusio- or thermo-osmosis, which generate flows by application of a macroscopic gradient (of electric potential, solute concentration or temperature). The driving force (e.g., electric or osmotic) is located typically within a nanometric distance to the surface and the resulting effects are thus expected to be strongly affected by modifications of surface properties. We show in this context that moderate departures from the no-slip hydrodynamic boundary condition can result in very large enhancement of most interfacially driven transport, - up to two orders of magnitude for hydrodynamic slip lengths in the nanometer range ! -. The amplification of the effect due to slippage scales as the ratio between the slip length and the interfacial characterisic length (debye length, or solute attraction or depletion range). These predictions are confirmed qualitatively and quantitatively by molecular dynamics simulation of electro- and diffusio -osmosis. We will discuss the pertinence of these effects for flow enhancement in nano- or micro- fluidic geometries, but also fortransport of macromolecules in externally applied or self- generated gradient, in line with recent experiments.

  10. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

  11. The safety of osmotically acting cathartics in colonic cleansing

    DEFF Research Database (Denmark)

    Nyberg, Caroline; Hendel, J.; Nielsen, O.H.

    2010-01-01

    Efficient cleansing of the colon before a colonoscopy or a radiological examination is essential. The osmotically acting cathartics (those given the Anatomical Therapeutic Chemical code A06AD) currently used for this purpose comprise products based on three main substances: sodium phosphate......, combinations of polyethylene glycol and electrolyte lavage solutions (PEG-ELS), and magnesium citrate. All these preparations give adequate cleansing results and have similar profiles in terms of the frequency and type of mild to moderate adverse effects. However, serious adverse events, such as severe...... hyperphosphatemia and irreversible kidney damage owing to acute phosphate nephropathy, have been reported after use of sodium-phosphate-based products. The aim of this Review is to provide an update on the potential safety issues related to the use of osmotically acting cathartics, especially disturbances of renal...

  12. Giant Osmotic Pressure in the Forced Wetting of Hydrophobic Nanopores

    Science.gov (United States)

    Michelin-Jamois, Millan; Picard, Cyril; Vigier, Gérard; Charlaix, Elisabeth

    2015-07-01

    The forced intrusion of water in hydrophobic nanoporous pulverulent material is of interest for quick storage of energy. With nanometric pores the energy storage capacity is controlled by interfacial phenomena. With subnanometric pores, we demonstrate that a breakdown occurs with the emergence of molecular exclusion as a leading contribution. This bulk exclusion effect leads to an osmotic contribution to the pressure that can reach levels never previously sustained. We illustrate, on various electrolytes and different microporous materials, that a simple osmotic pressure law accounts quantitatively for the enhancement of the intrusion and extrusion pressures governing the forced wetting and spontaneous drying of the nanopores. Using electrolyte solutions, energy storage and power capacities can be widely enhanced.

  13. Swelling and osmotic flow in a potential host rock

    International Nuclear Information System (INIS)

    Measurements of osmotic and hydraulic permeability are reported for a series of tests conducted on Opalinus Clay samples from the Mont Terri underground research laboratory in the Jura Mountains of NE Switzerland. Osmotic flow was observed across discs of this clay-shale separating 0,245 M NaCl solution from distilled water. Pressure transients monitored during constant flow rate testing were analysed to give permeability and specific storage values. The mean permeability normal to bedding of the two Opalinus Clay specimens was 7,9 x 10-21 m2. The mean specific storage based on all reliable determinations was 4,1 x 10-4 m-1. Values calculated from the steady-state pressure gradients established during constant flow rate testing were very close to those obtained by mathematical analysis of pressure transients. The calculation of the transients was carried out using a new model of flow and solute transport which included terms for the osmotic coupling. The form of the pressure transients and the magnitude of the strain seen during the tests lead to a revision to the definition of solid phase compressibility to incorporate a term dependent upon the osmotic coupling coefficient. Steady-state osmotic flow rates were in the range 0,1 to 0,6 μL.hr-1 when the specimens were placed between a sodium chloride solution with a theoretical osmotic pressure of 1,19 MPa and distilled water. Transient flow rates were substantially larger. Membrane efficiencies were found to be relatively low, ranging from 1% to 6% (mean around 4%). The mean osmotic permeability normal to bedding was 3,5 x 10-22 m2. Specific storage and pore compressibility values were substantially larger than anticipated, suggesting that the volumetric strain of the clay-shale under the conditions of laboratory testing must be largely determined by quasi-elastic deformation processes such as swelling and crack dilation. To test this hypothesis, a 3D swelling test was performed on a cubic specimen of the same

  14. Osmotic demyelination syndrome with a dysequilibrium syndrome: reversible MRI findings

    International Nuclear Information System (INIS)

    Neurological disorders may be seen in end-stage renal disease patients due to uraemia or to complications of dialysis. A dysequilibrium syndrome may be seen, usually soon after or towards the end of haemodialysis. This group of patients has no particular findings on MRI. On the other hand, the osmotic demyelination syndrome has definitive MRI findings, not to date reported with the dysequilibrium syndrome. We report a patient with end-stage renal disease and the dysequilibrium syndrome who showed findings of osmotic demyelination on MRI. The patient had a convulsion after a first haemodialysis, with quadriparesis and hyperactive deep tendon reflexes and bilateral Babinski signs. The upper motor neurone signs lasted for a week. Meanwhile, he was also dysarthric and had dysphagia. He recovered neurologically without any residuum following appropriate treatment and there was improvement on MRI. (orig.)

  15. Osmotic stress affects functional properties of human melanoma cell lines

    CERN Document Server

    La Porta, Caterina A M; Pasini, Maria; Laurson, Lasse; Alava, Mikko J; Zapperi, Stefano; Amar, Martine Ben

    2015-01-01

    Understanding the role of microenvironment in cancer growth and metastasis is a key issue for cancer research. Here, we study the effect of osmotic pressure on the functional properties of primary and metastatic melanoma cell lines. In particular, we experimentally quantify individual cell motility and transmigration capability. We then perform a circular scratch assay to study how a cancer cell front invades an empty space. Our results show that primary melanoma cells are sensitive to a low osmotic pressure, while metastatic cells are less. To better understand the experimental results, we introduce and study a continuous model for the dynamics of a cell layer and a stochastic discrete model for cell proliferation and diffusion. The two models capture essential features of the experimental results and allow to make predictions for a wide range of experimentally measurable parameters.

  16. Osmotically driven flows in microchannels separated by a semipermeable membrane

    Science.gov (United States)

    Bruus, Henrik; Hartvig Jensen, Kaare; Bohr, Tomas

    2008-11-01

    Osmotically driven flows in microchannels are studied experimentally and theoretically. The propagation of the front of sugar solutions has been measured using dye and particle tracking in 200 μm wide and 50, 100, and 200 μm high polymer-based microchannels. Each of these microchannels was separated by a semipermeable membrane from a reservoir containing pure water. We have also established a theoretical model of this system. In the limit of low axial flow resistance, our model predicts the propagation speed of the sugar front as a function of sugar concentration and channel geometry. The theoretical predictions agree well with the measurements. Our motivations for studying osmotically driven flows are that they are believed to be responsible for the translocation of sugar in plants and that they can be used as the driving mechanism in micropumps with no moveable parts.[5mm] This work was supported by the Danish National Research Foundation, Grant No. 74.

  17. Quorum sensing regulates the osmotic stress response in Vibrio harveyi.

    Science.gov (United States)

    van Kessel, Julia C; Rutherford, Steven T; Cong, Jian-Ping; Quinodoz, Sofia; Healy, James; Bassler, Bonnie L

    2015-01-01

    Bacteria use a chemical communication process called quorum sensing to monitor cell density and to alter behavior in response to fluctuations in population numbers. Previous studies with Vibrio harveyi have shown that LuxR, the master quorum-sensing regulator, activates and represses >600 genes. These include six genes that encode homologs of the Escherichia coli Bet and ProU systems for synthesis and transport, respectively, of glycine betaine, an osmoprotectant used during osmotic stress. Here we show that LuxR activates expression of the glycine betaine operon betIBA-proXWV, which enhances growth recovery under osmotic stress conditions. BetI, an autorepressor of the V. harveyi betIBA-proXWV operon, activates the expression of genes encoding regulatory small RNAs that control quorum-sensing transitions. Connecting quorum-sensing and glycine betaine pathways presumably enables V. harveyi to tune its execution of collective behaviors to its tolerance to stress. PMID:25313392

  18. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    Science.gov (United States)

    Lemay, Serge G.; Panja, Debabrata; Molineux, Ian J.

    2013-02-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution or culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection in vivo; the mechanism is perfectly consistent with phage genome ejection in vitro.

  19. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    CERN Document Server

    Lemay, Serge G; Molineux, Ian J

    2012-01-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly \\textit{in vitro}, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution/culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection \\textit{in vivo}; the mechanism is perfectly consistent with phage genome ejection \\textit{in vitro}.

  20. OPTIMIZATION OF OSMOTIC DEHYDRATION PROCESS OF PUMPKIN IN TERNARY SOLUTIONS

    OpenAIRE

    Ruth R. Bambicha; Miriam E. Agnelli; Rodolfo H. Mascheroni

    2012-01-01

    By applying the methodology of response surface analysis (RSM) optimum conditions were determined for maximum WL (water loss) and WR (weight reduction), and minimal SG (solute gain), NMC (normalized moisture content) and change of color (CC) for the osmotic dehydration (OD) of pumpkin (Cucurbita Moschata) in ternary solutions (water/sucrose/sodium chloride) carried out in 32 executions (n) by application of a Face-Centered Central Composite Design (CCF) that evaluated the effect of experiment...

  1. CONTROLLED-POROSITY OSMOTIC PUMP TABLETS-AN OVERVIEW

    OpenAIRE

    AJAY BABU,PRASADA RAO. VIJAYA RATNA

    2013-01-01

    Conventional drug delivery systems have little control over their drug release and almost no control over the effective concentration at the target site. This kind of dosing pattern may result in constantly changing, unpredictable plasma concentrations. Drugs can be delivered in a controlled pattern over a long period of time by the process of osmosis. Osmotic devices are the most promising strategy based systems for controlled drug delivery. They are the most reliable controlled drug deliver...

  2. A Case of Osmotic Demyelination Presenting with Severe Hypernatremia

    OpenAIRE

    Han, Min Jee; Kim, Do Hyoung; Kim, Young Hwa; Yang, In Mo; Park, Joon Hyung; Hong, Moon Ki

    2015-01-01

    Osmotic demyelination syndrome is a demyelinating disorder associated with rapid correction of hyponatremia. But, it rarely occurs in acute hypernatremia, and it leads to permanent neurologic symptoms and is associated with high mortality. A 44-year-old woman treated with alternative medicine was admitted with a history of drowsy mental status. Severe hypernatremia (197mEq/L) with hyperosmolality (415mOsm/kgH2O) was evident initially and magnetic resonance imaging revealed a high signal inten...

  3. Osmotic pressure in Ca/Na montmorillonite dispersions: Monte Carlo simulations

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In the past, clay-water systems have been extensively studied. due to its importance in agricultural as well as technological applications. A more recent use of clay is as sealing material for nuclear waste. The success for such a containment depends on the clay structure and its swelling properties. This means that the clay should be able to sustain considerable changes in the surrounding ground water including salinities of glacial melt water as well as sea water, while still being an effective hydraulic barrier. We have approached this problem using statistical mechanical simulation techniques. The osmotic pressure in Ca/Na montmorillonite dispersions has been calculated via Monte Carlo simulations. For a clay system in equilibrium with pure water, Monte Carlo simulations predict a large swelling when the clay counterions are monovalent, while in presence of divalent counterions a limited swelling is predicted with an aqueous layer between the clay lamellae of about 1 nm - in excellent agreement with SAXS data. Montmorillonite in contact with a salt reservoir with e.g. both Na and Ca counterions will only show a modest swelling unless the Na+ concentration in the bulk is several orders of magnitude larger than the Ca2+ concentration. This is true both for a clay repository surrounded by ground water as well as sea water of high salinity. The limited swelling of clay in presence of divalent counterions is a consequence of ion-ion correlations, which both reduce the entropic repulsion and give rise to an attractive component in the total osmotic pressure. Ion-ion correlations also favour divalent counterions when competing with monovalent ones. This is an important aspect for the retention of radioactive charged species. A more fundamental result of ion-ion correlations is that the osmotic pressure as a function of clay sheet separation becomes non-monotonic - which indicates the possibility of a phase separation

  4. Status of strangeness electro-production at MAMI

    International Nuclear Information System (INIS)

    At the Institut fuer Kernphysik in Mainz, Germany, the microtron MAMI has been upgraded to 1.5 GeV electron beam energy and can now be used to study strange hadronic systems. The magnetic spectrometer KAOS from GSI was dismantled and re-installed in the spectrometer facility operated by the A1 collaboration. The spectrometer's primary purpose is to study strangeness electro-production. Its compact design and its capability to detect negative and positive charged particles simultaneously under forward scattering angles complements the existing spectrometers. In 2008, an important milestone has been reached by the successful measurement of kaon production off a liquid hydrogen target. The identification of Λ and Σ0 hyperons in the missing mass spectra has demonstrated the capability of the extended facility to perform strangeness electro-production spectroscopy. To operate KAOS as a double-arm spectrometer under zero degree scattering angle major modifications are needed. A new vacuum chamber was constructed and installed, a new coordinate detector with many thousands of channels was built and tested, a new trigger system for the high rate environment was developed, and a magnetic chicane for the primary electron beam is under construction. (author)

  5. FORMULATION AND EVALUATION OF CONTROLLED POROSITY OSMOTIC TABLETS OF LORNOXICAM

    Directory of Open Access Journals (Sweden)

    A. Uma Maheswari*, K. Elango, Daisy Chellakumari, K. Saravanan and Anglina Jeniffer Samy

    2012-06-01

    Full Text Available The aim of the present study is to formulate and evaluate controlled release formulation of lornoxicam based on osmotic technology. Lornoxicam, a potent non-steroidal anti-inflammatory drug (NSAID with shorter half life, makes the development of sustained release (SR dosage forms extremely advantageous. However, due to its weak acidic nature, its release from SR delivery system is limited to the lower GIT which consequently leads to a delayed onset of its analgesic action. Basic pH modifier tromethamine and wicking agent SLS were incorporated into the core tablet to create basic environmental pH inside the tablets, which provide complete drug release that starts in the stomach to rapidly alleviate the painful symptoms and continue in the intestine to maintain protracted analgesic effect. The effect of different formulation variables namely level of osmogen (mannitol in the core tablet and level of pore former (sorbitol in the coating membrane on in-vitro release was studied. Lornoxicam release from controlled porosity osmotic pump was directly proportional to the pore former (sorbitol and level of osmogen (mannitol. Drug release from the developed formulations was independent of pH and agitational intensity and was dependent on osmotic pressure of the release media. Results of SEM studies showed the formation of pores in the membrane from where the drug release occurred. The optimized formulation was found to release the drug in zero order and found to be stable upon stability studies.

  6. Simultaneous measurement of peritoneal glucose and free water osmotic conductances.

    Science.gov (United States)

    La Milia, V; Limardo, M; Virga, G; Crepaldi, M; Locatelli, F

    2007-09-01

    Ultrafiltration (UF) failure is one of the most important causes of long-term peritoneal dialysis (PD) failure in patients. Osmotic forces acting across small and ultra-small pores generate a UF with solutes through the small pore and free water transport (FWT) through the ultra-small pore. The ability of glucose to exert an osmotic pressure sufficient to cause UF is the so-called 'osmotic conductance to glucose' (OCG) of the peritoneal membrane. Our study proposes a simple method to determine both the OCG and FWT. In 50 patients on PD, a Double Mini-Peritoneal Equilibration Test (Double Mini-PET), consisting of two Mini-PET, was performed consecutively. A solution of 1.36% glucose was used for the first test, whereas a solution of 3.86% glucose was used for the second test. The sodium removal values and the differences in UF between the two tests were used to calculate FWT and the OCG. Patients with UF failure showed significant reductions not only in the OCG and the FWT but also of UF of small pores. The Double Mini-PET is simple, fast, and could become useful to evaluate patients on PD in everyday clinical practice. PMID:17609692

  7. Osmotically controlled drug delivery system with associated drugs.

    Science.gov (United States)

    Gupta, Brahma Prakash; Thakur, Navneet; Jain, Nishi P; Banweer, Jitendra; Jain, Surendra

    2010-01-01

    Conventional drug delivery systems have slight control over their drug release and almost no control over the effective concentration at the target site. This kind of dosing pattern may result in constantly changing, unpredictable plasma concentrations. Drugs can be delivered in a controlled pattern over a long period of time by the controlled or modified release drug delivery systems. They include dosage forms for oral and transdermal administration as well as injectable and implantable systems. For most of drugs, oral route remains as the most acceptable route of administration. Certain molecules may have low oral bioavailability because of solubility or permeability limitations. Development of an extended release dosage form also requires reasonable absorption throughout the gastro-intestinal tract (GIT). Among the available techniques to improve the bioavailability of these drugs fabrication of osmotic drug delivery system is the most appropriate one. Osmotic drug delivery systems release the drug with the zero order kinetics which does not depend on the initial concentration and the physiological factors of GIT. This review brings out new technologies, fabrication and recent clinical research in osmotic drug delivery. PMID:21486532

  8. Active osmotic exchanger for advanced filtration at the nano scale

    Science.gov (United States)

    Marbach, Sophie; Bocquet, Lyderic

    2015-11-01

    One of the main functions of the kidney is to remove the waste products of an organism, mostly by excreting concentrated urea while reabsorbing water and other molecules. The human kidney is capable of recycling about 200 liters of water per day, at the relatively low cost of 0.5 kJ/L (standard dialysis requiring at least 150 kJ/L). Kidneys are constituted of millions of parallel filtration networks called nephrons. The nephrons of all mammalian kidneys present a specific loop geometry, the Loop of Henle, that is believed to play a key role in the urinary concentrating mechanism. One limb of the loop is permeable to water and the other contains sodium pumps that exchange with a common interstitium. In this work, we take inspiration from this osmotic exchanger design to propose new nanofiltration principles. We first establish simple analytical results to derive general operating principles, based on coupled water permeable pores and osmotic pumps. The best filtration geometry, in terms of power required for a given water recycling ratio, is comparable in many ways to the mammalian nephron. It is not only more efficient than traditional reverse osmosis systems, but can also work at much smaller pressures (of the order of the blood pressure, 0.13 bar, as compared to more than 30 bars for pressure-retarded osmosis systems). We anticipate that our proof of principle will be a starting point for the development of new filtration systems relying on the active osmotic exchanger principle.

  9. FORMULATION AND EVALUATION OF BACLOFEN CONTROLLED POROSITY OSMOTIC PUMP TABLETS

    Directory of Open Access Journals (Sweden)

    Indarapu Rajendra Prasad

    2013-06-01

    Full Text Available In the present study, attempts were made to develop and evaluate the controlled porosity osmotic pump (CPOP based drug delivery system of sparingly water soluble drug Baclofen. Formulation variables, such as, levels of solubility enhancer, ratio of drug to osmogents, coat thickness of semi permeable membrane (SPM and level of pore former were found to affect the drug release from the developed formulations. Cellulose acetate was used as the semi permeable membrane. Drug release was directly proportional to the level of the solubility enhancer, osmotic pressure generated by osmotic agent and level of pore former; however, was inversely proportional to the coat thickness of SPM. Drug release from developed formulations was independent of pH and agitation intensities of release media. Burst strength of the exhausted shells decreased with increase in the level of pore former. This system was found to deliver Baclofen at a zero-order rate. The optimized formulations were subjected to stability studies as per ICH guidelines, and formulations were found to be stable after 45days study.

  10. Osmotically driven flows in microchannels separated by a semipermeable membrane.

    Science.gov (United States)

    Jensen, Kåre Hartvig; Lee, Jinkee; Bohr, Tomas; Bruus, Henrik

    2009-07-21

    We have fabricated lab-on-a-chip systems with microchannels separated by integrated membranes allowing for osmotically driven microflows. We have investigated these flows experimentally by studying the dynamics and structure of the front of a sugar solution travelling in 200 microm wide and 50-200 microm deep microchannels. We find that the sugar front travels at a constant speed, and that this speed is proportional to the concentration of the sugar solution and inversely proportional to the depth of the channel. We propose a theoretical model, which, in the limit of low axial flow resistance, predicts that the sugar front should indeed travel with a constant velocity. The model also predicts an inverse relationship between the depth of the channel and the speed, and a linear relation between the sugar concentration and the speed. We thus find good qualitative agreement between the experimental results and the predictions of the model. Our motivation for studying osmotically driven microflows is that they are believed to be responsible for the translocation of sugar in plants through the phloem sieve element cells. Also, we suggest that osmotic elements can act as on-chip integrated pumps with no movable parts in lab-on-a-chip systems. PMID:19568680

  11. Development and Optimization of Cefaclor Gastroretentive Osmotic control release Tablets

    Directory of Open Access Journals (Sweden)

    Prasad Garrepally

    2014-03-01

    Full Text Available The purpose of this present research work was to development and optimization of different formulations of osmotic control gastroretentive tablets containing Cefaclor. The cefaclor osmotic control gastroretentive tablets was formulated by 3 step process involve core tablet, coating and pore forming. Core tablets were formulated by using different polymers HPMC, polyox and sodium CMC alone and in combination. Initially drug excipients interactions were carried by using FTIR spectra; results showed that there was no interaction. Twelve different formulations of cefaclor osmotic control gastroretentive were prepared and characterized for flow properties and physical properties. Results of these parameters were within the Pharmacopoeial limits. Floating behaviour of all formulations was reported to be less than 100sec of floating lag time and greater than 12hr of duration of floating. F 7 formulation was selected as a optimised based on in vitro drug release studies. It showed the drug release patters similar to that of theoretical release. In vitro dissolution data of all formulation were fit into different kinetic models to know the mechanism of drug release; results revealed that the optimised F 7 formulation gave perfect zero order type of drug transport. Finally, stability studies were performed for optimised formulation and result revealed no significant difference between before and after storage for selected formula.

  12. Development and evaluation of microporous osmotic tablets of diltiazem hydrochloride

    Directory of Open Access Journals (Sweden)

    Afifa Bathool

    2012-01-01

    Full Text Available Microporous osmotic tablet of diltiazem hydrochloride was developed for colon targeting. These prepared microporous osmotic pump tablet did not require laser drilling to deliver the drug to the specific site of action. The tablets were prepared by wet granulation method. The prepared tablets were coated with microporous semipermeable membrane and enteric polymer using conventional pan coating process. The incorporation of sodium lauryl sulfate (SLS, a leachable pore-forming agent, could form in situ delivery pores while coming in contact with gastrointestinal medium. The effect of formulation variables was studied by changing the amounts of sodium alginate and NaCMC in the tablet core, osmogen, and that of pore-forming agent (SLS used in the semipermeable coating. As the amount of hydrophilic polymers increased, drug release rate prolonged. It was found that drug release was increased as the concentration of osmogen and pore-former was increased. Fourier transform infrared spectroscopy and Differential scanning calorimetry results showed that there was no interaction between drug and polymers. Scanning electron microscopic studies showed the formation of pores after predetermined time of coming in contact with dissolution medium. The formation of pores was dependent on the amount of pore former used in the semipermeable membrane. in vitro results showed acid-resistant, timed release at an almost zero order up to 24 hours. The developed osmotic tablets could be effectively used for prolonged delivery of Diltiazem HCl.

  13. Polyamine metabolism and osmotic stress. I. Relation to protoplast viability

    Science.gov (United States)

    Tiburcio, A. F.; Masdeu, M. A.; Dumortier, F. M.; Galston, A. W.

    1986-01-01

    Cereal leaves subjected to the osmotica routinely used for protoplast isolation show a rapid increase in arginine decarboxylase activity, a massive accumulation of putrescine, and slow conversion of putrescine to the higher polyamines, spermidine and spermine (HE Flores, AW Galston 1984 Plant Physiol 75: 102). Mesophyll protoplasts from these leaves, which have a high putrescine:polyamine ratio, do not undergo sustained division. By contrast, in Nicotiana, Capsicum, Datura, Trigonella, and Vigna, dicot genera that readily regenerate plants from mesophyll protoplasts, the response of leaves to osmotic stress is opposite to that in cereals. Putrescine titer as well as arginine and ornithine decarboxylase activities decline in these osmotically stressed dicot leaves, while spermidine and spermine titers increase. Thus, the putrescine:polyamine ratio in Vigna protoplasts, which divide readily, is 4-fold lower than in oat protoplasts, which divide poorly. We suggest that this differing response of polyamine metabolism to osmotic stress may account in part for the failure of cereal mesophyll protoplasts to develop readily in vitro.

  14. Silicon electro-optic modulator with high-permittivity gate dielectric layer

    Institute of Scientific and Technical Information of China (English)

    Mengxia Zhu; Zhiping Zhou; Dingshan Gao

    2009-01-01

    A high-permittivity (high-k) material is applied as the gate dielectric layer in a silicon metal-oxidesemiconductor (MOS) capacitor to form a special electro-optic (EO) modulator.Both induced charge density and modulation efficiency in the proposed modulator are improved due to the special structure design and the application of the high-k material.The device has an ultra-compact dimension of 691 μm in length.

  15. Electrolytic treatment of liquid effluents: decontamination by electro coagulation of release water of a petroleum platform

    International Nuclear Information System (INIS)

    The water releases of petroleum platforms present lots of pollutants; Usually, these waters are reinjected in ground water when it is possible. In the other cases they are released at the surface and need then a treatment. The electro-coagulation is a suitable method often used. The authors propose to study the optimum conditions of decontamination by this method, by a parametric evaluation (water flow, charge density, ph). Experiments used iron and aluminium electrodes. (A.L.B.)

  16. Dynamic mesh refinement for discrete models of jet electro-hydrodynamics

    OpenAIRE

    Lauricella, Marco; Pontrelli, Giuseppe; Pisignano, Dario; Succi, Sauro

    2015-01-01

    Nowadays, several models of unidimensional fluid jets exploit discrete element methods. In some cases, as for models aiming at describing the electrospinning nanofabrication process of polymer fibers, discrete element methods suffer a non constant resolution of the jet representation. We develop a dynamic mesh-refinement method for the numerical study of the electro-hydrodynamic behavior of charged jets using discrete element methods. To this purpose, we import ideas and techniques from the s...

  17. Physics of Giant ElectroMagnetic Pulse generation in short pulse laser experiments

    OpenAIRE

    Poyé, Alexandre; Hulin, Sébastien; Bailly-Grandvaux, Mathieu; Dubois, Jean-Luc; Ribolzi, Jérôme; Raffestin, Didier; Bardon, Matthieu; Lubrano-Lavaderci, Frédéric; D'Humières, Emmanuel; Santos, Joao Jorge; Nicolaï, Philippe; Tikhonchuk, Vladimir

    2015-01-01

    In this paper we describe the physical processes that lead to the generation of Giant Electro- Magnetic Pulses (GEMP) on powerful laser facilities. Our study is based on experimental mea- surements of both the charging of a solid target irradiated by an ultra-short, ultra-intense laser and the detection of the electromagnetic emission in the GHz domain. An unambiguous correlation between the neutralisation current in the target holder and the electromagnetic emission shows that the source of ...

  18. Evaluating Pt-Ru/C mixtures as ethanol electro-oxidation catalysers

    OpenAIRE

    Bibian Alonso Hoyos; Javier González; Carlos Sánchez

    2010-01-01

    This work studies ethanol electro-catalytic oxidation by cyclic voltametry in sulphuric acid solutions at different temperatures and concetrations, using platinum.rutenium mixtures supported in vitreous carbon as catalysers. The results indicate that ethanol oxidation in theses electrodes is irreversible, has slow kinetics, is controlled by charge transfer and is brought about by a bi-functional reaction mechanism, this being ethanol adsorption on platinum atoms and additional oxidation of sp...

  19. Recent experimental data may point to a greater role for osmotic pressures in the subsurface

    Science.gov (United States)

    Neuzil, C.E.; Provost, A.M.

    2009-01-01

    Uncertainty about the origin of anomalous fluid pressures in certain geologic settings has caused researchers to take a second look at osmosis, or flow driven by chemical potential differences, as a pressure-generating process in the subsurface. Interest in geological osmosis has also increased because of an in situ experiment by Neuzil (2000) suggesting that Pierre Shale could generate large osmotic pressures when highly compacted. In the last few years, additional laboratory and in situ experiments have greatly increased the number of data on osmotic properties of argillaceous formations, but they have not been systematically examined. In this paper we compile these data and explore their implications for osmotic pressure generation in subsurface systems. Rather than base our analysis on osmotic efficiencies, which depend strongly on concentration, we calculated values of a quantity we term osmotic specific surface area (Aso) that, in principle, is a property of the porous medium only. The Aso values are consistent with a surprisingly broad spectrum of osmotic behavior in argillaceous formations, and all the formations tested exhibited at least a modest ability to generate osmotic pressure. It appears possible that under appropriate conditions some formations can be highly effective osmotic membranes able to generate osmotic pressures exceeding 30 MPa (3 km of head) at porosities as high as ??0.1 and pressures exceeding 10 MPa at porosities as high as ??0.2. These findings are difficult to reconcile with the lack of compelling field evidence for osmotic pressures, and we propose three explanations for the disparity: (1) Our analysis is flawed and argillaceous formations are less effective osmotic membranes than it suggests; (2) the necessary subsurface conditions, significant salinity differences within intact argillaceous formations, are rare; or (3) osmotic pressures are unlikely to be detected and are not recognized when encountered. The last possibility, that

  20. Electro-hydrodynamic investigations of fluids in complex systems by NMR mapping experiments and computer simulations

    International Nuclear Information System (INIS)

    Nuclear Magnetic Resonance (NMR) techniques offer valuable insights into the transport phenomena in complex systems like porous media. This cumulative thesis presents a number of experimental NMR mapping techniques for retrieving and recording valuable information about transport quantities in simple and complex geometries. NMR investigation protocols have been developed for velocity mapping, acceleration mapping, ionic current density mapping and electro-hydrodynamic mapping. Complementary information about the same objects can be obtained in most situations with the aid of Computational Fluid Dynamics (CFD) simulations. This procedure allowed us a direct comparison between the experimental and simulated data. The simple objects presented here are to be seen as test devices for microfluidics, and the complex percolation structures as model objects for real porous materials. The acceleration mapping technique developed here allows the direct measurement of spatial acceleration distributions in simple and complex test objects. Experimentally recorded acceleration maps highlighted the tortuous pathway of the fluid in site-correlated percolation objects. The correlated site-percolation models presented here try to mimic the high connectivity of the real porous materials, as they occur in nature. Well established NMR investigation protocols and CFD simulations permitted us to characterize the test objects only from the geometrical (percolation threshold, correlation length, fractal dimension) but also from the dynamic point of view. Transport phenomena under combined action of pressure and electrical field gradients are of interest for many microfluidics applications. Electroosmotic flow patterns are strongly modified by hydrodynamic pressure gradients and ionic current density distributions built up in the pore system. The appearance of closed loops and vortices was detected. Electro-osmotic flow and current density mapping reveal dissimilarity in the Helmholtz

  1. Dynamics in simultaneous electro-generative leaching for sphalerite-MnO2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The principle for the electro-generative leaching was applied to simultaneous leaching of sphalerite-MnO2. A galvanic system for the bio-electro-generative leaching was set up. The effects of grain size and temperature on rate of zinc extraction from sphalerite under the conditions of presence and absence ofAcidithiobacillusferrooxidans (A.ferrooxidans) were studied, respectively.The results show that with bacteria, the maximum extraction of zinc from the ores with grain size of 16.6 μm can reach 32.01% after leaching for 12 h, while to obtain the same extraction ratio in the traditional bio-leaching route (i.e. not electro-generative one) 10 d is needed to ore granules with same size. The unreacted shrinking core model was used for describing the reaction-relative and diffusion-relative phenomena presented in the process of the electro-generative leaching with and without bacteria, which is considered to be diffusion controlled. The activation energies of the anodic reaction for leaching system in the presence and absence of bacteria are 11.97 and 14.39 kJ/mol, respectively, indicating that leaching rate can be decreased by A. ferrooxidans. SEM was used to study the effect of A. ferrooxidans on the ores in the simultaneous electro-generative leaching, which indicates that the produced sulfur on the surface of the sulfides can be oxidized by A. ferrooxidans after bio-electro-generative leaching for 24 h, and the transferred charge due to the bacterial oxidation is up to 17.86%, which is an important part of the output electric quantity.

  2. Storage of osmotically treated entomopathogenic nematode Steinernema carpocapsae

    Institute of Scientific and Technical Information of China (English)

    SHI-PENG FENG; RI-CHOU HAN; XUE-HONG QIU; LI CAO; JING-HUA CHEN; GUO-HONG WANG

    2006-01-01

    The infective juveniles (IJs) of Steinernema carpocapsae 'All' were osmotically stressed by a mixture of ionic (fortified artificial seawater) and non-ionic (3.2 mol/Lglycerol) solutions to establish a method for osmotic storage of entomopathogenic nematodes.Seven combinations (termed solution A to G) with different proportions of these two solutions were tested, with sterile extra pure water (sepH2O, termed solution H) as a control. The mortality of the IJs at a concentration of 5 × 105 IJ/mL in the solutions A to G, and H were 13.2%,16.2%, 16.7%, 13.5%, 25.2%, 31.6%, 44.6%, and 1.0%, respectively, after 21 days storage at 25℃. Most of the IJs shrunk and stopped motility after 6-9 hours incubation at 25℃ in solutions A to D. Based on the results, solutions A to D and H were chosen to further test the osmotic survival of the IJs at different IJ concentrations (5×105, 2.5 × 105, 2000 IJ/mL) and incubation temperature (30℃, 25℃, 10℃). The resulting IJs were exposed to a high temperature assay (45℃ for 4 h, HTA). Osmotically stressed IJs showed improved heat tolerance. The mortality of the IJs increased with the increasing concentrations of the test IJs and the storage temperatures after exposing to the HTA. More than 88.4%, 62.3% or 2.4% of the treated IJs died at the above three IJ concentrations, respectively. At the three IJ concentrations (2 000 IJs/mL, 2.5 × 105 IJs/mL or 5 × 105 IJs/mL), the highest mortality was recorded in solution D (11.6%, 85.9% or 98.0%, respectively), and the lowest mortality in solution B (2.4%, 62.3% or 86.6%, respectively). No untreated IJs survived after the heat treatment. During 42 days storage at 10℃, the IJs mortality in the solutions A to D and H were 7.19%, 5.97%,4.41%, 4.34%, and 4.34% respectively, and showed no significant differences. In conclusion,solutions enhances the heat tolerance. The mortality of the IJs after HTA increased with the increasing concentrations of the test IJs and the storage

  3. SAXS investigations on lipid membranes under osmotic stress

    International Nuclear Information System (INIS)

    Full text: In this work we, experimentally, investigate the interactions between lipid bilayers. A structural characterization is performed by small angle x-ray scattering (SAXS) on multilamellar systems under known osmotic pressure. Changes in the composition of membranes can modify their mechanical properties and structural parameters, like the flexibility of these membranes, which plays a key role on the determination of the tridimensional organization of bilayers. The membranes are composed of soya lecithin, where the major component is DPPC (Dipalmitoylphosphatidylcholine), and fatty acids are incorporated to the membrane in different concentrations, in order to turn the membrane more fluid. The membranes are inserted in a solution of PVP [poly(vinyl-pyrrolidone) - 40000] and the polymer will apply an osmotic pressure on them. The osmotic pressure is controlled by preparing PVP solutions of desired composition and, as we know the concentration of polymer in solution, we can obtain the intensity of the osmotic pressure. SAXS experiments were done in order to determine the distance between the bilayer. From the position of the Bragg peaks, the lamellar periodicity (the thickness of the membranes plus their distance of separation) was determined. Using theoretical model for the form and structure factors we fitted those experimental data and determined the thickness of the membranes. The distance between the membranes was controlled by the osmotic pressure (P) applied to the membranes and, for a given pressure, we determine the distance between the bilayers (a) on equilibrium. The experimental curve P(a) is theoretically described by the different contributions from van der Waals, hydration and fluctuation forces. From the fitting of experimental curves, relevant parameters characterizing the strength of the different interactions are obtained, such as Hamaker and rigidity constant [2, 3]. We observe that the separation between the bilayers on equilibrium is

  4. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest Lab., WA (United States)

    1996-08-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated as one of the enabling technologies for advanced energy systems. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that promises an order of magnitude increase in deposition rates and achievable coating thicknesses. Since this regime borders on and exceeds the normal operating limits of existing ESD electronic equipment, development is in progress to produce equipment that can consistently and reliably achieve these conditions for a broad range of materials. Progress so far has resulted in a consistent 500% increase in deposition rates, and greater rates still are anticipated. Technology transfer activities are a significant portion of the ESD program effort. Notable successes now include the start-up of a new business to commercialize the ESD technology, the incorporation of the process into the operations of a major gas turbine manufacturer, major new applications in gas turbine blade and steam turbine blade protection and repair, and in military, medical, metal-working, and recreational equipment applications.

  5. Dissipative electro-elastic network model of protein electrostatics

    International Nuclear Information System (INIS)

    We propose a dissipative electro-elastic network model to describe the dynamics and statistics of electrostatic fluctuations at active sites of proteins. The model combines the harmonic network of residue beads with overdamped dynamics of the normal modes of the network characterized by two friction coefficients. The electrostatic component is introduced to the model through atomic charges of the protein force field. The overall effect of the electrostatic fluctuations of the network is recorded through the frequency-dependent response functions of the electrostatic potential and electric field at the protein active site. We also consider the dynamics of displacements of individual residues in the network and the dynamics of distances between pairs of residues. The model is tested against loss spectra of residue displacements and the electrostatic potential and electric field at the heme's iron from all-atom molecular dynamics simulations of three hydrated globular proteins. (paper)

  6. Dissipative electro-elastic network model of protein electrostatics

    CERN Document Server

    Martin, Daniel R; Matyushov, Dmitry V

    2011-01-01

    We propose a dissipative electro-elastic network model (DENM) to describe the dynamics and statistics of electrostatic fluctuations at active sites of proteins. The model combines the harmonic network of residue beads with overdamped dynamics of the normal modes of the network characterized by two friction coefficients. The electrostatic component is introduced to the model through atomic charges of the protein force field. The overall effect of the electrostatic fluctuations of the network is recorded through the frequency-dependent response functions of the electrostatic potential and electric field at the active site. We also consider the dynamics of displacements of individual residues in the network and the dynamics of distances between pairs of residues. The model is tested against loss spectra of residue displacements and the electrostatic potential and electric field at the heme's iron from all-atom molecular dynamics simulations of three hydrated globular proteins.

  7. Electro-acoustic solitary waves in dusty plasmas

    International Nuclear Information System (INIS)

    present a rigorous theoretical investigation of electro- acoustic [particularly, dust-ion acoustic (DIA) and dust-acoustic (DA)] solitary waves in dusty plasmas. We employ the reductive perturbation method for small but finite amplitude solitary waves as well as the pseudo-potential approach for arbitrary amplitude ones. We also analyze the effects of non-planar geometry and dust charge fluctuations on both DIA and DA solitary waves, the effect of finite ion-temperature on DIA solitary waves, and the effects of dust-fluid temperature and non-isothermal ion distributions on DA solitary waves. It has been reported that these effects do not only significantly modify the basic features of DIA or DA solitary waves, but also introduce some important new features. The basic features and the underlying physics of DIA and DA solitary waves, which are relevant to space and laboratory dusty plasmas, are briefly discussed. (author)

  8. Uniqueness of photon spheres in electro-vacuum spacetimes

    Science.gov (United States)

    Cederbaum, Carla; Galloway, Gregory J.

    2016-04-01

    In a recent paper (Cederbaum C and Galloway G J 2015 Commun. Analysis Geom. at press), the authors established the uniqueness of photon spheres in static vacuum asymptotically flat spacetimes by adapting Bunting and Masood-ul-Alam’s proof of static vacuum black hole uniqueness. Here, we establish uniqueness of suitably defined sub-extremal photon spheres in static electro-vacuum asymptotically flat spacetimes by adapting the argument of Masood-ul-Alam (1992 Class. Quantum Grav. 9 L53-5). As a consequence of our result, we can rule out the existence of electrostatic configurations involving multiple ‘very compact’ electrically charged bodies and sub-extremal black holes.

  9. Medically relevant ElectroNeedle technology development.

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Carrie Frances; Thomas, Michael Loren; McClain, Jaime L.; Harper, Jason C.; Achyuthan, Komandoor E.; Ten Eyck, Gregory A.

    2008-11-01

    ElectroNeedles technology was developed as part of an earlier Grand Challenge effort on Bio-Micro Fuel Cell project. During this earlier work, the fabrication of the ElectroNeedles was accomplished along with proof-of-concept work on several electrochemically active analytes such as glucose, quinone and ferricyanide. Additionally, earlier work demonstrated technology potential in the field of immunosensors by specifically detecting Troponin, a cardiac biomarker. The current work focused upon fabrication process reproducibility of the ElectroNeedles and then using the devices to sensitively detect p-cresol, a biomarker for kidney failure or nephrotoxicity. Valuable lessons were learned regarding fabrication assurance and quality. The detection of p-cresol was accomplished by electrochemistry as well as using fluorescence to benchmark ElectroNeedles performance. Results from these studies will serve as a guide for the future fabrication processes involving ElectroNeedles as well as provide the groundwork necessary to expand technology applications. One paper has been accepted for publication acknowledging LDRD funding (K. E. Achyuthan et al, Comb. Chem. & HTS, 2008). We are exploring the scope for a second paper describing the applications potential of this technology.

  10. Method and tool for expanding tubular members by electro-hydraulic forming

    Science.gov (United States)

    Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

    2013-10-29

    An electro-hydraulic forming tool having one or more electrodes for forming parts with sharp corners. The electrodes may be moved and sequentially discharged several times to form various areas of the tube. Alternatively, a plurality of electrodes may be provided that are provided within an insulating tube that defines a charge area opening. The insulating tube is moved to locate the charge area opening adjacent one of the electrodes to form spaced locations on a preform. In other embodiments, a filament wire is provided in a cartridge or supported by an insulative support.

  11. Advances in understanding of osmotic dehydration and vacuum impregnation of fruits

    OpenAIRE

    Tylewicz, Urszula

    2011-01-01

    Osmotic Dehydration and Vacuum Impregnation are interesting operations in the food industry with applications in minimal fruit processing and/or freezing, allowing to develop new products with specific innovative characteristics. Osmotic dehydration is widely used for the partial removal of water from cellular tissue by immersion in hypertonic (osmotic) solution. The driving force for the diffusion of water from the tissue is provided by the differences in water chemical potential between ...

  12. Formulation and evaluation of verapamil hydrochloride osmotic controlled release matrix tablets

    OpenAIRE

    Vidyadhara, S.; R. L. C. Sasidhar; V Uma Maheswara Rao; C. H. Showri Babu; D. Lakshmi Harika

    2014-01-01

    Osmotically controlled oral drug delivery systems utilize osmotic pressure as energy source for the controlled delivery of drugs, independent of pH and hydrodynamic conditions of gastrointestinal tract (GIT). The present study was aimed to develop osmotic controlled extended release formulations of verapamil hydrochloride an angiotensin II receptor antagonist with anti-hypertensive activity. Verapamil hydrochloride matrix tablets were prepared by direct compression process using hydroxypropyl...

  13. Development and Evaluation of Swellable Elementary Osmotic Pump Tablet of Glipizide

    OpenAIRE

    Preethi N; Sujatha S

    2013-01-01

    A novel type of elementary osmotic pump [EOP] tablet for efficient delivery of poorly water-soluble drug, glipizide has been designed. Drug release from the system, called Swellable Elementary Osmotic Pump [SEOP], is through a delivery orifice in the form of a very fine dispersion, ready for dissolution and absorption. SEOP tablets were prepared by compressing the mixture of micronized drug and excipients into convex tablet. The effect of wetting agent, swelling agent, osmotic agent and hydro...

  14. On-chip electro membrane extraction

    DEFF Research Database (Denmark)

    Petersen, Nickolaj Jacob; Jensen, Henrik; Hansen, Steen Honore;

    2010-01-01

    This paper presents the first downscaling of electro membrane extraction (EME) to a chip format. The voltage-controlled extraction for sample preparation on microfluidic devices has several advantages such as selective extraction removing the high ionic strength of biological samples, preconcentr......This paper presents the first downscaling of electro membrane extraction (EME) to a chip format. The voltage-controlled extraction for sample preparation on microfluidic devices has several advantages such as selective extraction removing the high ionic strength of biological samples...... basic drugs were selectively extracted from the flowing sample solution, into the organic phase SLM, and further into just 7 mu I of 10 mM HCI, serving as acceptor solution. Subsequently, the acceptor solution was analyzed by capillary electrophoresis. The electro membrane chip was highly efficient...

  15. Swelling, mechanical and friction properties of PVA/PVP hydrogels after swelling in osmotic pressure solution.

    Science.gov (United States)

    Shi, Yan; Xiong, Dangsheng; Liu, Yuntong; Wang, Nan; Zhao, Xiaoduo

    2016-08-01

    The potential of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogels as articular cartilage replacements was in vitro evaluated by using a macromolecule-based solution to mimic the osmotic environment of cartilage tissue. The effects of osmotic pressure solution on the morphology, crystallinity, swelling, mechanical and friction properties of PVA/PVP hydrogels were investigated by swelling them in non-osmotic and osmotic pressure solutions. The results demonstrated that swelling ratio and equilibrium water content were greatly reduced by swelling in osmotic solution, and the swelling process was found to present pseudo-Fickian diffusion character. The crystallization degree of hydrogels after swelling in osmotic solution increased more significantly when it compared with that in non-osmotic solution. After swelling in osmotic solution for 28days, the compressive tangent modulus and storage modulus of hydrogels were significantly increased, and the low friction coefficient was reduced. However, after swelling in the non-osmotic solution, the compressive tangent modulus and friction coefficient of hydrogels were comparable with those of as-prepared hydrogels. The better material properties of hydrogels in vivo than in vitro evaluation demonstrated their potential application in cartilage replacement. PMID:27157740

  16. THE EFFECT OF EMI EHF ON ELECTRO - KINETIC POTENTIAL OF CELL NUCLEAR MEMBRANES OF WHEAT SEEDLINGS TREATED WITH HYBBERELLIC ACID

    Directory of Open Access Journals (Sweden)

    Vardevanyan Poghos O

    2013-09-01

    Full Text Available The effect of hybberellic acid and EMI EHF on electro kinetic potential changes of cell nuclear membrane of wheat seedlings has been investigated. It was revealed that electro kinetic potential value depends on functional state of plant organism. It was reported that the treatment of wheat germs with hybberellic acid and EMI EHF induces a change of nuclear membrane surface charge. It was revealed that the combined influence of chemical as well as physical factors induces more pronounced response on biological systems as compared to separately. It was also observed that the effect of EMI EHF has significant effect on water resonant frequencies as compared to water non- resonant frequencies.

  17. Reprint of: Coulomb field strength measurement by electro-optic spectral decoding system at the CALIFES beam line

    Science.gov (United States)

    Pan, R.; Jamison, S. P.; Lefevre, T.; Gillespie, W. A.

    2016-09-01

    Electro-optic (EO) techniques are increasingly used for longitudinal bunch profile measurements. A bunch profile monitor, based on electro-optic spectral decoding (EOSD), has been developed and demonstrated on the CALIFES beam line at CERN. The EO response is analysed using a frequency domain description, and two methods for extraction of absolute Coulomb field strengths from the electron bunch are demonstrated. Measurements at field strengths up to 1.3 MV/m agree with the expectation based on independent charge measurements.

  18. Temperature dependence studies on the electro-oxidation of aliphatic alcohols with modified platinum electrodes

    Indian Academy of Sciences (India)

    Panadda Katikawong; Tanakorn Ratana; Waret Veerasai

    2009-05-01

    Temperature dependence on the electro-oxidation of methanol, ethanol and 1-propanol in 0.5 M H2SO4 were investigated with Pt and PtRu electrodes. Tafel slope and apparent activation energy were evaluated from the cyclic voltammetric data in the low potential region (0.3-0.5 V vs SHE). The CV results provided Tafel slopes for alcohols in the range of 200-400 mV dec-1 which indicated a difference in the rate determining step. The decrease in Tafel slope was only observed in the case of methanol for the Ru-modified Pt electrode. This indicates that Ru improves the rate of determining step for methanol while hindering it for the other alcohols. The electrochemical impedance spectroscopy was also used to evaluate the electro-oxidation mechanism of alcohols on these electrodes. The simulated EIS results provided two important parameters: charge transfer resistance () and inductance (). The $R^{-1}_{ct}$ and -1 represent the rate of alcohol electro-oxidation and rate of desorption of intermediate species, respectively. These values increased with the increasing of temperature. The results from two techniques were well agreed that the electro-oxidation of methanol was improved by raising the temperature and ruthenium modification.

  19. Surface charge measurement by the Pockels effect

    CERN Document Server

    Sam, Y L

    2001-01-01

    have been observed by applying both impulse and AC voltages to a needle electrode in direct contact with the BSO. AC surface discharge behaviour of polymeric materials bonded to the BSO has also been investigated. The effect of the surrounding environment has been experimentally examined by placing the cell inside a vacuum chamber. Surface charge measurements have been made at various atmospheric pressures. The effect of an electro-negative gas (Sulphur Hexafluoride) on the surface charge distribution has also been investigated. This thesis is concerned with the design and development of a surface charge measurement system using Pockels effect. The measurement of surface charge is important in determining the electrical performance of high voltage insulation materials. The method proposed allows on-line measurement of charge and can generate two-dimensional images that represent the charge behaviour on the surface of the material under test. The measurement system is optical and uses a Pockels crystal as the ...

  20. An osmotic model of the growing pollen tube.

    Directory of Open Access Journals (Sweden)

    Adrian E Hill

    Full Text Available Pollen tube growth is central to the sexual reproduction of plants and is a longstanding model for cellular tip growth. For rapid tip growth, cell wall deposition and hardening must balance the rate of osmotic water uptake, and this involves the control of turgor pressure. Pressure contributes directly to both the driving force for water entry and tip expansion causing thinning of wall material. Understanding tip growth requires an analysis of the coordination of these processes and their regulation. Here we develop a quantitative physiological model which includes water entry by osmosis, the incorporation of cell wall material and the spreading of that material as a film at the tip. Parameters of the model have been determined from the literature and from measurements, by light, confocal and electron microscopy, together with results from experiments made on dye entry and plasmolysis in Lilium longiflorum. The model yields values of variables such as osmotic and turgor pressure, growth rates and wall thickness. The model and its predictive capacity were tested by comparing programmed simulations with experimental observations following perturbations of the growth medium. The model explains the role of turgor pressure and its observed constancy during oscillations; the stability of wall thickness under different conditions, without which the cell would burst; and some surprising properties such as the need for restricting osmotic permeability to a constant area near the tip, which was experimentally confirmed. To achieve both constancy of pressure and wall thickness under the range of conditions observed in steady-state growth the model reveals the need for a sensor that detects the driving potential for water entry and controls the deposition rate of wall material at the tip.

  1. Sporadic hypokalemic paralysis caused by osmotic diuresis in diabetes mellitus.

    Science.gov (United States)

    Vishnu, Venugopalan Y; Kattadimmal, Anoop; Rao, Suparna A; Kadhiravan, Tamilarasu

    2014-07-01

    A wide variety of neurological manifestations are known in patients with diabetes mellitus. We describe a 40-year-old man who presented with hypokalemic paralysis. On evaluation, we found that the cause of the hypokalemia was osmotic diuresis induced by marked hyperglycemia due to undiagnosed diabetes mellitus. The patient had an uneventful recovery with potassium replacement, followed by glycemic control with insulin. Barring a few instances of symptomatic hypokalemia in the setting of diabetic emergencies, to our knowledge uncomplicated hyperglycemia has not been reported to result in hypokalemic paralysis. PMID:24472241

  2. The osmotic tissue expander: a three-year clinical experience.

    Science.gov (United States)

    Obdeijn, Miryam C; Nicolai, Jean-Philippe A; Werker, Paul M N

    2009-09-01

    Closure of defects after trauma or excision of neoplasms is a basic skill in plastic surgery. Local, regional and distant flaps lead to additional scars. Skin recruitment by serial excision or skin expansion is a less damaging option for defects that must be closed. Advantages of tissue expansion include good colour and texture match. Disadvantages are the need for a second operation, use of an implant with the attendant risk of infection, time needed for inflation of the device, repeat visits to the clinic, and punctures to inflate the expander. To overcome the last disadvantage, an osmotic expander was developed in Germany in 1999 by OSMED GmbH (Ilmenau). PMID:18755643

  3. Optimization of process parameters for osmotic dehydration of papaya cubes

    OpenAIRE

    S.K. Jain; R. C. Verma; Murdia, L. K.; Jain, H. K.; Sharma, G. P.

    2010-01-01

    Process temperature (30, 40 and 50 °C), syrup concentration (50, 60 and 70o Brix) and process time (4, 5 and 6 h) for osmotic dehydration of papaya (Carica papaya) cubes were optimized for the maximum water loss and optimum sugar gain by using response surface methodology. The peeled and pre-processed papaya cubes of 1 cm size were immersed in sugar syrup at constant temperature water bath having syrup to papaya cubes ratio of 4:1 (w/w). The cubes were removed from bath at pre-decided time, r...

  4. 49 CFR 236.817 - Switch, electro-pneumatic.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch, electro-pneumatic. 236.817 Section 236.817 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, electro-pneumatic. A switch operated by an electro-pneumatic switch-and-lock movement....

  5. Electro Catalytic Oxidation (ECO) Operation

    Energy Technology Data Exchange (ETDEWEB)

    Morgan Jones

    2011-03-31

    The power industry in the United States is faced with meeting many new regulations to reduce a number of air pollutants including sulfur dioxide, nitrogen oxides, fine particulate matter, and mercury. With over 1,000 power plants in the US, this is a daunting task. In some cases, traditional pollution control technologies such as wet scrubbers and SCRs are not feasible. Powerspan's Electro-Catalytic Oxidation, or ECO{reg_sign} process combines four pollution control devices into a single integrated system that can be installed after a power plant's particulate control device. Besides achieving major reductions in emissions of sulfur dioxide (SO{sub 2}), nitrogen oxides (NOx), fine particulate matter (PM2.5) and mercury (Hg), ECO produces a highly marketable fertilizer, which can help offset the operating costs of the process system. Powerspan has been operating a 50-MW ECO commercial demonstration unit (CDU) at FirstEnergy Corp.'s R.E. Burger Plant near Shadyside, Ohio, since February 2004. In addition to the CDU, a test loop has been constructed beside the CDU to demonstrate higher NOx removal rates and test various scrubber packing types and wet ESP configurations. Furthermore, Powerspan has developed the ECO{reg_sign}{sub 2} technology, a regenerative process that uses a proprietary solvent to capture CO{sub 2} from flue gas. The CO{sub 2} capture takes place after the capture of NOx, SO{sub 2}, mercury, and fine particulate matter. Once the CO{sub 2} is captured, the proprietary solution is regenerated to release CO{sub 2} in a form that is ready for geological storage or beneficial use. Pilot scale testing of ECO{sub 2} began in early 2009 at FirstEnergy's Burger Plant. The ECO{sub 2} pilot unit is designed to process a 1-MW flue gas stream and produce 20 tons of CO{sub 2} per day, achieving a 90% CO{sub 2} capture rate. The ECO{sub 2} pilot program provided the opportunity to confirm process design and cost estimates, and prepare for large

  6. The Electro-Optic Beam Position Monitor

    CERN Document Server

    Doherty, James

    2013-01-01

    This reports outlines the development of a new ultra-wideband electro-optic beam position monitor (EO-BPM) for use in the Large Hadron Collider (LHC) which utilises birefringent crystals and the Pockels effect to monitor beam position. The physical principles behind the operation of the device and tested topology, which incorporates two Lithium Tantalate crystals, is discussed.

  7. Electro-optical Position-Measuring System

    Science.gov (United States)

    Tcheng, Ping; Schott, Timothy D.

    1991-01-01

    Electro-optical system developed to measure five components of coordinates representing position and orientation of model in test section of wind tunnel. Located entirely outside test section, uses small lasers as sources of light and self-scanning linear photodiode arrays (LPDA's) as sensing elements. With improvements in measuring ranges, adapted for use in other aerodynamic applications.

  8. Electro-impulse Method of Surface Cleaning

    OpenAIRE

    Bekbolat R. Nussupbekov; Kappas Kussaynov; Аyanbergen К. Khassenov

    2013-01-01

    This article is focused on the qualitative assessment of the electro-impulse method of surface cleaning efficiency. Heat exchanger tubes are cleaned under the action of blast waves created by the high voltage discharge in the liquid. The article presents dependences of degree of surface purification on the impulse voltage at switching device and on spark rate

  9. Electro-impulse Method of Surface Cleaning

    Directory of Open Access Journals (Sweden)

    Bekbolat R. Nussupbekov

    2013-01-01

    Full Text Available This article is focused on the qualitative assessment of the electro-impulse method of surface cleaning efficiency. Heat exchanger tubes are cleaned under the action of blast waves created by the high voltage discharge in the liquid. The article presents dependences of degree of surface purification on the impulse voltage at switching device and on spark rate

  10. Electro-optic voltage sensor head

    Science.gov (United States)

    Crawford, Thomas M.; Davidson, James R.; Woods, Gregory K.

    1999-01-01

    The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers.

  11. THEORY OF SIMILARITY OF ELECTRO MEMBRANE SYSTEMS WITH REGARD TO FORCED, GRAVITATIONAL AND ELECTRO CONVECTION

    OpenAIRE

    Kovalenko A. V.; Pismenskiy A. V.; Urtenov M. K.

    2015-01-01

    In the article, we have suggested a general mathematical model of non-stationary and non-isothermal process of a binary electrolyte transfer in dilute solutions in an electro-membrane system (EMS), taking into account the joint action of gravitational convection, forced convection and electro convection in potential dynamic mode. This model is a boundary problem for a system of two-dimensional quasi-linear Navier-Stokes equation and Nernst-Planck-Poisson in partial derivatives equation. We ha...

  12. Thermal and Osmotic Tolerance of 'Irukandji' Polyps: Cubozoa; Carukia barnesi.

    Directory of Open Access Journals (Sweden)

    Robert Courtney

    Full Text Available This research explores the thermal and osmotic tolerance of the polyp stage of the Irukandji jellyfish Carukia barnesi, which provides new insights into potential polyp habitat suitability. The research also targets temperature, salinity, feeding frequency, and combinations thereof, as cues for synchronous medusae production. Primary findings revealed 100% survivorship in osmotic treatments between 19 and 46‰, with the highest proliferation at 26‰. As salinity levels of 26‰ do not occur within the waters of the Great Barrier Reef or Coral Sea, we conclude that the polyp stage of C. barnesi is probably found in estuarine environments, where these lower salinity conditions commonly occur, in comparison to the medusa stage, which is oceanic. Population stability was achieved at temperatures between 18 and 31°C, with an optimum temperature of 22.9°C. We surmise that C. barnesi polyps may be restricted to warmer estuarine areas where water temperatures do not drop below 18°C. Asexual reproduction was also positively correlated with feeding frequency. Temperature, salinity, feeding frequency, and combinations thereof did not induce medusae production, suggesting that this species may use a different cue, possibly photoperiod, to initiate medusae production.

  13. Osmotic concentration of polypeptides from hemofiltrate of uremic patients.

    Science.gov (United States)

    Ehrlich, K; Holland, F; Turnham, T; Klein, E

    1980-07-01

    Hemofiltrate from uremic patients was concentrated 15- to 40-fold by osmotic removal of water across a reverse osmosis membrane which retains salts and proteins. Salts and low molecular weight components were removed from the concentrate by partial dialysis using a highly impermeable cellulose membrane. Following this desalting step, 100- to 500-fold concentration could be achieved by evaporation at low pressure. The concentrate was fractionated on Sephadex G15 columns. Fractions were tested for their toxicity to human cells in culture. Fractions containing components with molecular weights greater than 700 daltons inhibited 3H-thymidine incorporation into the DNA of HeLa and skin fibroblast cells more than did low molecular weight peptides and an iso-osmolar control. Components eluting in the molecular weight range of angiotensin I and vitamin B-12 were most inhibitory. These studies show that hemofiltrate from uremic patients is a readily available source of toxic polypeptides. The osmotic concentration and gel chromatographic procedures described should make available large amounts of these molecules for further studies. PMID:7408253

  14. Does osmotic distillation change the isotopic relation of wines?

    Directory of Open Access Journals (Sweden)

    Schmitt Matthias

    2014-01-01

    Full Text Available Currently partial alcohol reduction of wine is in the focus of research worldwide. There are several technologies available to achieve this target. These techniques are either based on distilling or membrane processes. Osmotic distillation, one of the possibilities, is a quite modern membrane process that can be used. During that process, wine is pumped in counter flow to water along a micro porous, hydrophobic membrane. The volatile components of the wine can permeate that membrane and are dissolved in water. The driving force of that process is the vapor pressure difference between the volatiles on the wine and water side of the membrane. The aim of this work was to determine if the alcohol reduction by osmotic distillation can change the isotopic relation in a wine. Can this enological practice change the composition of a wine in a way that an illegal water addition is simulated? Different wines were reduced by 2% alcohol v/v with varying process parameters. The isotopic analysis of the O 16/18 ratio in the wine were performed according to the OIV methods (353/2009 These analyses showed that the isotopic ratio is modified by an alcohol reduction of 2% v/v in a way that corresponds to an addition of 4–5% of external water.

  15. Osmotically driven flows in microchannels separated by a semipermeable membrane

    CERN Document Server

    Jensen, Kaare Hartvig; Bohr, Tomas; Bruus, Henrik

    2008-01-01

    We perform experimental investigations of osmotically driven flows in artificial microchannels by studying the dynamics and structure of the front of a sugar solution traveling in 200 um wide and 50-200 um deep microchannels. We find that the sugar front travels with constant speed, and that this speed is proportional to the concentration of the sugar solution and inversely proportional to the depth of the channel. We propose a theoretical model, which, in the limit of low axial flow resistance, predicts that the sugar front indeed should travel with a constant velocity. The model also predicts an inverse relationship between the depth of the channel and the speed and a linear relation between the sugar concentration and the speed. We thus find good agreement between the experimental results and the predictions of the model. Our motivation for studying osmotically driven flows is that they are believed to be responsible for the translocation of sugar in plants through the phloem sieve element cells. Also, we ...

  16. Preparation and In Vitro/In Vivo Evaluation of Vinpocetine Elementary Osmotic Pump System

    Directory of Open Access Journals (Sweden)

    Meiying Ning

    2011-01-01

    Full Text Available Preparation and in vitro and in vivo evaluation of vinpocetine (VIN elementary osmotic pump (EOP formulations were investigated. A method for the preparation of VIN elementary osmotic pump tablet was obtained by adding organic acid additives to increase VIN solubility. VIN was used as the active pharmaceutical ingredient, lactose and mannitol as osmotic agent. Citric acid was used as increasing API solubility and without resulting in the API degradation. It is found that the VIN release rate was increasing with the citric acid amount at a constant range. Cellulose acetate 398-3 was employed as semipermeable membrane containing polyethylene glycol 6000 and diethyl-o-phthalate as pore-forming agent and plasticizer for controlling membrane permeability. In addition, a clear difference between the pharmacokinetic patterns of VIN immediate release and VIN elementary osmotic pump formulations was revealed. The area under the plasma concentration-time curve after oral administration of elementary osmotic pump formulations was equivalent to VIN immediate release formulation. Furthermore, significant differences found for mean residence time, elimination half-life, and elimination rate constant values corroborated prolonged release of VIN from elementary osmotic pump formulations. These results suggest that the VIN osmotic pump controlled release tablets have marked controlled release characters and the VIN osmotic pump controlled release tablets and the normal tablets were bioequivalent.

  17. The osmotic pressure of 3He-4He mixtures along the phase separation curve

    International Nuclear Information System (INIS)

    The osmotic pressure of 3He-4He mixtures was measured along the phase separation curve at temperatures up to 500 mK by balancing it with the fountain pressure of pure 4He. The usefullness of the secondary osmotic pressure thermometer was reinvestigated. (Auth.)

  18. Renal blood flow, early distal sodium, and plasma renin concentrations during osmotic diuresis

    DEFF Research Database (Denmark)

    Leyssac, P P; Holstein-Rathlou, N H; Skøtt, O

    2000-01-01

    significant inverse relationship between superficial nephron ED(NaCl) and PRC. We conclude that ED(Na) decreases during osmotic diuresis, suggesting that the increase in PRC was mediated by the macula densa. The results suggest that the natriuresis during osmotic diuresis is a result of impaired sodium...

  19. Sedimentation equilibria of ferrofluids: II. Experimental osmotic equations of state of magnetite colloids

    NARCIS (Netherlands)

    Luigjes, B.; Thies-Weesie, D.M.E.; Erné, B.H.; Philipse, A.P.

    2012-01-01

    The first experimental osmotic equation of state is reported for well-defined magnetic colloids that interact via a dipolar hard-sphere potential. The osmotic pressures are determined from the sedimentation equilibrium concentration profiles in ultrathin capillaries using a low-velocity analytical c

  20. ‘Wine Glass’ sign in recurrent postpartum hypernatremic osmotic cerebral demyelination

    OpenAIRE

    Saroja, Aralikatte O.; Karkal R Naik; Rajendra V Mali; Sanjeeva R Kunam

    2013-01-01

    Osmotic demyelination syndrome resulting from postpartum hypernatremia is a recently described entity wherein young women present with hypernatremic encephalopathy and white matter hyperintensities along with quadriparesis from rhabdomyolysis. It is an acute monophasic condition with acute hypernatremia occurring during puerperium with good recovery in majority of the patients with treatment. To the best of our knowledge, recurrent postpartum hypernatremia with encephalopathy, osmotic demyeli...

  1. Velocity evolution of electro-magnetically driven shock wave for beam-dissociated hydrogen interaction experiment

    Science.gov (United States)

    Kondo, Kotaro; Oguri, Yoshiyuki

    2016-03-01

    We present the velocity measurements in electro-magnetic shock tube for beam interaction experiment by three methods; laser refraction, photodiode for self-emission, and high speed framing camera. The laser refraction showed that the average shock velocity was 6.7 km/s when the initial pressure was 1000 Pa and the initial charging voltage was 16 kV. The self-emissions from piston discharge plasma were measured by photodiodes and by high speed framing camera. The measurements showed that the duration between shock and piston was up to 8 microseconds with a 400-mm propagation in the shock tube, which is enough time as dissociation target for beam interaction experiment.The complementary velocity measurement is significant for understanding the electro-magnetically driven shock physics.

  2. Colloid osmotic pressure in decompensated cirrhosis. A 'mirror image' of portal venous hypertension

    DEFF Research Database (Denmark)

    Henriksen, J H

    1985-01-01

    Colloid osmotic pressure in plasma (IIP) and ascitic fluid (IIA) and hydrostatic pressures in the hepatoportal system were measured simultaneously in 20 patients with decompensated cirrhosis. IIP was significantly decreased (mean, 21 mm Hg, versus normal, 30 mm Hg; P less than 0.01), and IIA was....../IIP (r = -0.77, P less than 0.001). WHV--IVCP was in most patients in the same order as and closely correlated to effective colloid osmotic pressure (IIP--IIA) (r = 0.88, P less than 0.001). No relationship was found between WHV--IVCP and IIP. The results indicate that a fall in colloid osmotic pressure...... in the interstitial space and ascitic fluid is related to and most likely secondary to the elevated portal pressure in decompensated cirrhosis. Effective colloid osmotic pressure may therefore be regarded as a 'mirror image' of transmural portal pressure. The role of colloid osmotic pressure in the...

  3. Design and Development of Osmotic Drug Delivery System for Anti-Hypertensive Agent

    Directory of Open Access Journals (Sweden)

    Shah N

    2013-04-01

    Full Text Available Controlled porosity osmotic tablet of Atenolol prepared and evaluated in this study. Atenolol is v lowsoluble drug. So it is difficult to formulate osmotic tablet of Atenolol which gives drug release up to 24hr at zero order. To get desired dissolution profile various formulation parameters like osmogenconcentration, level of weight gain and level of pore former concentration were studied. Polysorbate 80was added as solubilizer to increase its dissolution rate and get drug release up to 24 hr at zero order. Asconcentration of solubilizer increases, dissolution rate increases. Final optimized formulation wasstudied for effect of pH of dissolution media, agitation intensity and osmotic pressure of dissolutionmedia. There is no effect of pH of dissolution media and agitation intensity on dissolution. There issignificant effect of osmotic pressure on dissolution confirms that prepared Atenolol tablet gives drugrelease in osmotically control manner.

  4. ENHANCING OSMOTIC DEHYDRATION WITH ACOUSTIC CAVITATION%声空化强化渗透脱水

    Institute of Scientific and Technical Information of China (English)

    孙宝芝; 姜任秋; 淮秀兰; 李斌; 刘登瀛

    2004-01-01

    An experimental study was carried out to enhance osmotic dehydration of fruits--apples using acoustic cavitation. The variation in water losses and dry matter gain rates of materials with solute concentration, cavitation intensity, the thickness of materials and treating time segment during osmotic dehydration was discussed, at the same time, the influence of different materials on mass transfer during osmotic dehydration using acoustic cavitation was investigated. The results showed that water losses rates of materials were remarkably increased during osmotic dehydration using acoustic cavitation, but dry matter gain rates increased very little. Meanwhile the physical mechanism of enhanced mass transfer during osmotic dehydration with acoustic cavitation was clarified on the basis of analyzing the experimental results.

  5. Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

    Science.gov (United States)

    Nouralishahi, Amideddin; Rashidi, Ali Morad; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Choolaei, Mohammadmehdi

    2015-04-01

    The electro-catalytic behavior of Pt-CoOx/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH4 as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoOx, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of COads on Pt active sites by the participation of CoOx. Compared to Pt/MWCNTs, Pt-CoOx/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoOx/MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups controls the total rate of MOR process.

  6. Performance efficiency of electro-coagulation coupled electro-flotation process (EC–EF) versus adsorption process in Doxycycline removal from aqueous solutions

    OpenAIRE

    Zaidi, S; Chaabane, T.; Sivasankar, V.; Darchen, A.; Maachi, R.; Msagati, T. A. M; Prabhakaran, M

    2016-01-01

    International audience Two treatment methodologies such as electro-coagulation coupled electro-flotation (EC–EF) and adsorption have been adopted to remove doxycycline hyclate (DCH) from the aqueous solution. An electro-coagulation (EC) coupled electro-flotation (EF) system has been designed in a closed reactor with a capacity of 1.5L on a laboratory scale. Electro-synthesis of alumina (electro-generated alumina, EGA) using aluminium electrodes with magnesium chloride as an electrolyte was...

  7. Space charge dynamics in pressboard-oil-pressboard multilayer system under DC voltages

    OpenAIRE

    Fu, Mingli; Luo, Bing; Hou, Shuai; Liao, Yifan; Hao, Miao; Chen, George

    2015-01-01

    Converter transformers play a critical role in HVDC power transmission system. Space charge is a general concern for dielectric system under DC field. In this paper, the space charge behavior in a sandwiched oil-pressboard insulation system has been investigated using the pulsed electro-acoustic (PEA) method. The presence of homo-charges in the pressboards bulk and hetero-charges at the two interfaces between oil gap and pressboards leads to the electric field enhancement in the pressboards b...

  8. Is osmotic pressure relevant in the confinement of a polymer brush

    International Nuclear Information System (INIS)

    Polymer brushes are highly dense arrays of polymers grafted to an interface and are powerful ways to control the forces of adhesion, lubrication and friction. A key property of the brush that governs its behavior is how the structure of the brush responds to external forces and to confinement. We have developed a unique new setup that combines a surface force type apparatus with neutron reflection. Using this device, we measured the structure of polymer brushes under confinement. The brushes consisted of either the neutral poly(ethylene oxide), PEO, or the weakly charged poly(acrylic acid), PAA. Without confinement, both PEO and PAA brushes are found to be highly swollen with water, yielding the expected parabolic brush structure. Compression of the PEO brushes with as little as 0.5 bar of confining pressure is enough to reduce the brush to a polymer block of uniform density that is significantly dehydrated (<12% v/v of water). For the charged PAA brush (at pH 9), we observe the same transition from parabolic profile to nearly dehydrated block profile, but it occurs between 1 and 5 bars of confining pressure. These experimental results are compared against a theoretical model based on numerical selfconsistent field (nSCF) theory. Whilst the nSCF model correctly predicts the observed transition from a brush to a block profile, it predicts that we should need a confining pressure a factor of 100 greater than observed in our experiments. Looking also at SFA and AFM data, we will discuss further the role of osmotic pressure in a confined polymer brush.

  9. A charge-driven molecular water pump.

    Science.gov (United States)

    Gong, Xiaojing; Li, Jingyuan; Lu, Hangjun; Wan, Rongzheng; Li, Jichen; Hu, Jun; Fang, Haiping

    2007-11-01

    Understanding and controlling the transport of water across nanochannels is of great importance for designing novel molecular devices, machines and sensors and has wide applications, including the desalination of seawater. Nanopumps driven by electric or magnetic fields can transport ions and magnetic quanta, but water is charge-neutral and has no magnetic moment. On the basis of molecular dynamics simulations, we propose a design for a molecular water pump. The design uses a combination of charges positioned adjacent to a nanopore and is inspired by the structure of channels in the cellular membrane that conduct water in and out of the cell (aquaporins). The remarkable pumping ability is attributed to the charge dipole-induced ordering of water confined in the nanochannels, where water can be easily driven by external fields in a concerted fashion. These findings may provide possibilities for developing water transport devices that function without osmotic pressure or a hydrostatic pressure gradient. PMID:18654410

  10. Fractional charges

    International Nuclear Information System (INIS)

    20 years ago fractional charges were imagined to explain values of conductivity in some materials. Recent experiments have proved the existence of charges whose value is the third of the electron charge. This article presents the experimental facts that have led theorists to predict the existence of fractional charges from the motion of quasi-particles in a linear chain of poly-acetylene to the quantum Hall effect. According to the latest theories, fractional charges are neither bosons nor fermions but anyons, they are submitted to an exclusive principle that is less stringent than that for fermions. (A.C.)

  11. Osmotic pressure induced tensile forces in tendon collagen

    Science.gov (United States)

    Masic, Admir; Bertinetti, Luca; Schuetz, Roman; Chang, Shu-Wei; Metzger, Till Hartmut; Buehler, Markus J.; Fratzl, Peter

    2015-01-01

    Water is an important component of collagen in tendons, but its role for the function of this load-carrying protein structure is poorly understood. Here we use a combination of multi-scale experimentation and computation to show that water is an integral part of the collagen molecule, which changes conformation upon water removal. The consequence is a shortening of the molecule that translates into tensile stresses in the range of several to almost 100 MPa, largely surpassing those of about 0.3 MPa generated by contractile muscles. Although a complete drying of collagen would be relevant for technical applications, such as the fabrication of leather or parchment, stresses comparable to muscle contraction already occur at small osmotic pressures common in biological environments. We suggest, therefore, that water-generated tensile stresses may play a role in living collagen-based materials such as tendon or bone.

  12. Effect of osmotic pressure to bioimpedance indexes of erythrocyte suspensions

    Science.gov (United States)

    Melnikov, A. A.; Nikolaev, D. V.; Malahov, M. V.; Smirnov, A. V.

    2012-12-01

    In the paper we studied effects of osmotic modification of red blood cells on bioimpedance parameters of erythrocyte suspension. The Cole parameters: the extracellular (Re) and intracellular (Ri) fluid resistance, the Alpha parameter, the characteristic frequency (Fchar) and the cell membranes capacitance (Cm) of concentrated erythrocyte suspensions were measured by bioimpedance analyser in the frequency range 5 - 500 kHz. Erythrocytes were incubated in hypo-, hyper- and isoosmotic solutions to achieve changes in cell volume. It was found that Re and Alpha increased in the suspensions with low osmolarity and decreased in the hypertonic suspensions. Ri, Fchar and Cm were higher in the hyperosmotic and were lower in the hypoosmotic suspensions. Correlations of all BIS parameters with MCV were obtained, but multiple regression analysis showed that only Alpha parameter was independently related to MCV (β=0.77, p=0.01). Thus Alpha parameter may be related the mean corpuscular volume of cells.

  13. Effect of osmotic pressure to bioimpedance indexes of erythrocyte suspensions

    International Nuclear Information System (INIS)

    In the paper we studied effects of osmotic modification of red blood cells on bioimpedance parameters of erythrocyte suspension. The Cole parameters: the extracellular (Re) and intracellular (Ri) fluid resistance, the Alpha parameter, the characteristic frequency (Fchar) and the cell membranes capacitance (Cm) of concentrated erythrocyte suspensions were measured by bioimpedance analyser in the frequency range 5 – 500 kHz. Erythrocytes were incubated in hypo-, hyper- and isoosmotic solutions to achieve changes in cell volume. It was found that Re and Alpha increased in the suspensions with low osmolarity and decreased in the hypertonic suspensions. Ri, Fchar and Cm were higher in the hyperosmotic and were lower in the hypoosmotic suspensions. Correlations of all BIS parameters with MCV were obtained, but multiple regression analysis showed that only Alpha parameter was independently related to MCV (β=0.77, p=0.01). Thus Alpha parameter may be related the mean corpuscular volume of cells.

  14. Osmotically driven flows in microchannels separated by a semipermeable membrane

    DEFF Research Database (Denmark)

    Jensen, Kåre Hartvig; Lee, J.; Bohr, Tomas;

    2009-01-01

    We have fabricated lab-on-a-chip systems with microchannels separated by integrated membranes allowing for osmotically driven microflows. We have investigated these flows experimentally by studying the dynamics and structure of the front of a sugar solution travelling in 200 mu m wide and 50-200 mu...... m deep microchannels. We find that the sugar front travels at a constant speed, and that this speed is proportional to the concentration of the sugar solution and inversely proportional to the depth of the channel. We propose a theoretical model, which, in the limit of low axial flow resistance......, predicts that the sugar front should indeed travel with a constant velocity. The model also predicts an inverse relationship between the depth of the channel and the speed, and a linear relation between the sugar concentration and the speed. We thus find good qualitative agreement between the experimental...

  15. GABA not only a neurotransmitter: osmotic regulation by GABAAR signalling

    Directory of Open Access Journals (Sweden)

    Tiziana Cesetti

    2012-01-01

    Full Text Available In neurons the anionic channel γ-aminobutyric (GABA A receptor (GABAAR plays a central role in mediating both the neurotrophic and neurotransmitter role of GABA. Activation of this receptor by GABA also affects the function of non-neuronal cells in the central nervous system (CNS, as GABAARs are expressed in mature macroglia and in almost all progenitor types, including neural stem cells. The relevance of GABA signalling in non-neuronal cells has been comparatively less investigated than in neurons. However, it is becoming increasingly evident that these cells are direct targets of GABA regulation. In non-neuronal cells GABAAR activation leads to influx or efflux of chloride (Cl- depending on the electrochemical gradient. Ion transport is indissolubly associated to water fluxes across the plasma membrane and plays a key role in brain physiology. Therefore, GABAAR could affect osmotic tension in the brain by modulating ion gradients. In addition, since water movements also occur through specialized water channels and transporters, GABAAR signalling could affect the movement of water also by regulating the function of the channels and transporters involved, thereby affecting not only the direction of the water fluxes but also their dynamics. This regulation has consequences at the cellular level as it modulates cell volume and activates multiple intracellular signalling mechanisms important for cell proliferation, maturation and survival. It may also have consequences at the systemic level. For example, it may indirectly control neuronal excitability, by regulating the extracellular space and interstitial concentration of Cl-, and contribute to brain water homeostasis. Therefore, GABAergic osmotic regulation should be taken into account during the treatment of pathologies requiring the administration of GABAAR modulators and for the development of therapies for diseases causing water unbalance in the brain.

  16. Atrial natriuretic peptide mediates oxytocin secretion induced by osmotic stimulus.

    Science.gov (United States)

    Chriguer, Rosengela S; Antunes-Rodrigues, José; Franci, Celso R

    2003-02-15

    Atrial natriuretic peptide (ANP), first discovered in the heart, has been also detected in various brain regions involved in the control of cardiovascular function and water and sodium balance. The anteroventral region of the third ventricle (AV3V) and the subfornical organ (SFO) have ANP-immunoreactive projections towards the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. Extracellular fluid (ECF) hyperosmolality stimulates the secretion of oxytocin (OT) which induces ANP release by the atrium. On the other hand, passive immunoneutralization of ANP reduces OT secretion in response to ECF hypertonicity. Previous studies have shown the co-localization of ANP and OT in PVN and SON neurons and in the periventricular region, as well as the presence of ANPergic and oxytocinergic neurons in the median eminence. The aim of the present study was to investigate the OT and ANP content in the SON and PVN of the hypothalamus and in the posterior pituitary (PP) after an osmotic stimulus that induces OT secretion. The results showed that intracerebroventricular microinjection of normal rabbit serum (NRS) or of ANP antiserum followed or not by an intraperitoneal injection of isotonic saline did not alter OT secretion or OT content in the PVN, SON, and PP; passive ANP immunoneutralization reduced the basal content of ANP in the PVN, SON, and PP of animals in a situation of isotonicity; the ANP antiserum inhibited the increase of OT secretion and content of OT and ANP in the PVN, SON and PP induced by the osmotic stimulus. Thus, the increase in plasma OT and oxytocinergic neurons of the hypothalamus-posterior pituitary system in response to hypertonicity depends on the action of endogenous ANP, i.e., ECF hypertonicity must activate ANPergic neurons which directly or indirectly stimulate OT release. PMID:12576148

  17. Net Fluorescein Flux Across Corneal Endothelium Strongly Suggests Fluid Transport is due to Electro-osmosis.

    Science.gov (United States)

    Sanchez, J M; Cacace, V; Kusnier, C F; Nelson, R; Rubashkin, A A; Iserovich, P; Fischbarg, J

    2016-08-01

    We have presented prior evidence suggesting that fluid transport results from electro-osmosis at the intercellular junctions of the corneal endothelium. Such phenomenon ought to drag other extracellular solutes. We have investigated this using fluorescein-Na2 as an extracellular marker. We measured unidirectional fluxes across layers of cultured human corneal endothelial (HCE) cells. SV-40-transformed HCE layers were grown to confluence on permeable membrane inserts. The medium was DMEM with high glucose and no phenol red. Fluorescein-labeled medium was placed either on the basolateral or the apical side of the inserts; the other side carried unlabeled medium. The inserts were held in a CO2 incubator for 1 h (at 37 °C), after which the entire volume of the unlabeled side was collected. After that, label was placed on the opposite side, and the corresponding paired sample was collected after another hour. Fluorescein counts were determined with a (Photon Technology) DeltaScan fluorometer (excitation 380 nm; emission 550 nm; 2 nm bwth). Samples were read for 60 s. The cells utilized are known to transport fluid from the basolateral to the apical side, just as they do in vivo in several species. We used 4 inserts for influx and efflux (total: 20 1-h periods). We found a net flux of fluorescein from the basolateral to the apical side. The flux ratio was 1.104 ± 0.056. That difference was statistically significant (p = 0.00006, t test, paired samples). The endothelium has a definite restriction at the junctions. Hence, an asymmetry in unidirectional fluxes cannot arise from osmosis, and can only point instead to paracellular solvent drag. We suggest, once more, that such drag is due to electro-osmotic coupling at the paracellular junctions. PMID:26989056

  18. Charge-induced patchy attractions between proteins.

    Science.gov (United States)

    Li, Weimin; Persson, Björn A; Morin, Maxim; Behrens, Manja A; Lund, Mikael; Zackrisson Oskolkova, Malin

    2015-01-15

    Static light scattering (SLS) combined with structure-based Monte Carlo (MC) simulations provide new insights into mechanisms behind anisotropic, attractive protein interactions. A nonmonotonic behavior of the osmotic second virial coefficient as a function of ionic strength is here shown to originate from a few charged amino acids forming an electrostatic attractive patch, highly directional and complementary. Together with Coulombic repulsion, this attractive patch results in two counteracting electrostatic contributions to the interaction free energy which, by operating over different length scales, is manifested in a subtle, salt-induced minimum in the second virial coefficient as observed in both experiment and simulations. PMID:25494398

  19. Testing of electro-optical imaging systems

    Science.gov (United States)

    Chrzanowski, Krzysztof; Barela, Jaroslaw; Firmanty, Krzysztof

    2004-08-01

    Humans cannot objectively judge electro-optical imaging systems looking on an image of typical scenery. Quality of the image can be bad for some people but good for others and therefore objective test methods and advanced equipment are needed to evaluate these imaging systems. Test methods and measuring systems that enable reliable testing and evaluation of modern thermal cameras, color and monochrome TV cameras, LLLTV cameras and image intensifier systems are presented in this paper.

  20. Electro- and magnetostatic variations in SSC tunnel

    International Nuclear Information System (INIS)

    Applications of electro- and magnetostatic fields for very high energy accelerators such as the proposed 20 TeV Superconducting Super Collider (SSC) or Desertron are discussed. The possibility of replacing the quadrupole and even the dipole magnetic fields with electrostatic fields is examined. On the other hand, the Rare Earth Cobalt (REC) alloys offer the application of high remanent magnetostatic dipole fields, too. A possible combination of electrostatic and magnetostatic fields is discussed. (author)

  1. Electro-optical hybrid slip ring

    Science.gov (United States)

    Hong, En

    2005-11-01

    The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility

  2. Conception of Electro-Stimulation System

    OpenAIRE

    Adil Salbi; Seddik Bri

    2014-01-01

    The aim of this work is to suggest a reliable solution of electro-stimulation making it possible to restore defective functions of the nervous systems among certain patients. This solution consists in creating a signal similar to that arriving of the central nervous system. Thus, work presented aims to design an electronic circuit of stimulation allowing the contraction of the muscle to restore its function by a biphasic train of electric impulse. This stimulator system is composed of a clock...

  3. Physics of Giant ElectroMagnetic Pulse generation in short pulse laser experiments

    CERN Document Server

    Poyé, Alexandre; Bailly-Grandvaux, Mathieu; Dubois, Jean-Luc; Ribolzi, Jérôme; Raffestin, Didier; Bardon, Matthieu; Lubrano-Lavaderci, Frédéric; D'Humières, Emmanuel; Santos, Joao Jorge; Nicolaï, Philippe; Tikhonchuk, Vladimir

    2015-01-01

    In this paper we describe the physical processes that lead to the generation of Giant Electro- Magnetic Pulses (GEMP) on powerful laser facilities. Our study is based on experimental mea- surements of both the charging of a solid target irradiated by an ultra-short, ultra-intense laser and the detection of the electromagnetic emission in the GHz domain. An unambiguous correlation between the neutralisation current in the target holder and the electromagnetic emission shows that the source of the GEMP is the remaining positive charge inside the target after the escape of fast electrons accelerated by the ultra-intense laser. A simple model for calculating this charge in the thick target case is presented. From this model and knowing the geometry of the target holder, it becomes possible to estimate the intensity and the dominant frequencies of the GEMP on any facility.

  4. Osmotic pressure of ionic liquids in an electric double layer: Prediction based on a continuum model

    Science.gov (United States)

    Moon, Gi Jong; Ahn, Myung Mo; Kang, In Seok

    2015-12-01

    An analysis has been performed for the osmotic pressure of ionic liquids in the electric double layer (EDL). By using the electromechanical approach, we first derive a differential equation that is valid for computing the osmotic pressure in the continuum limit of any incompressible fluid in EDL. Then a specific model for ionic liquids proposed by Bazant et al. [M. Z. Bazant, B. D. Storey, and A. A. Kornyshev, Phys. Rev. Lett. 106, 046102 (2011), 10.1103/PhysRevLett.106.046102] is adopted for more detailed computation of the osmotic pressure. Ionic liquids are characterized by the correlation and the steric effects of ions and their effects are analyzed. In the low voltage cases, the correlation effect is dominant and the problem becomes linear. For this low voltage limit, a closed form formula is derived for predicting the osmotic pressure in EDL with no overlapping. It is found that the osmotic pressure decreases as the correlation effect increases. The osmotic pressures at the nanoslit surface and nanoslit centerline are also obtained for the low voltage limit. For the cases of moderately high voltage with high correlation factor, approximate formulas are derived for estimating osmotic pressure values based on the concept of a condensed layer near the electrode. In order to corroborate the results predicted by analytical studies, the full nonlinear model has been solved numerically.

  5. A high pressure cell for simultaneous osmotic pressure and x-ray diffraction measurements

    International Nuclear Information System (INIS)

    In this paper, we report on a novel osmotic cell, developed to simultaneously subject a sample to osmotic stress and measure structural changes by small angle x-ray diffraction. The osmotic cell offers many advantages over more conventional methods of osmotically stressing soft materials to measure their structural response. In particular, a full osmotic analysis can be performed with a single small sample (25 μl). This reduces sample handling and the associated systematic errors, as well as enabling tight control and monitoring of the thermodynamic environment during osmosis, thereby increasing measurement precision. The cell design enables control of osmotic pressure to ±0.04 bar over a pressure range of 1-100 bar, and temperature control to ±0.05 deg. C. Under these conditions, the lattice spacing in lyotropic structures was resolved to better than ±0.005 A. Using the osmotic cell, we demonstrate good agreement with previous conventional measurements on the energy of dehydrating the fluid lamellar phase of dioleoylphosphatidylcholine in water.

  6. An overview of osmotic power generation and its scope in Pakistan

    International Nuclear Information System (INIS)

    The need of introducing innovative power generation methods is increasing rapidly. The conventional fuel driven methods not only require heavy financial investments, they have also been held responsible for many natural calamities faced by the human population. While the research on better utilizing the renewable resources such as wind, tidal and wave energy etc is underway, the Osmotic Power has been commercially introduced as a new fuel-free energy resource. The energy in the osmotic power is derived from the difference in salt concentration between the fresh water and the salt water. In an osmotic power plant, the river water is used as the fresh water and the sea water is treated as the salt water for getting electric power through osmosis. While the hydroelectric dams can threat irrigation activities in some areas by blocking the water supply, the osmotic plants are situated at locations where the river water falls into the sea and hence cause no water hold-ups. In this paper, we take an in-depth look into the technical methods and the associated challenges of the osmotic power generation. We highlight the scope of osmotic power in Pakistan. We identify important geographical locations in the country which can be ideal for setting up an osmotic power station. (author)

  7. A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Zhu, Jianhua

    2010-04-16

    Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have previously identified salt overly sensitive (sos) mutants of Arabidopsis that fall into five loci, SOS1 to SOS5. These loci are required for the regulation of ion homeostasis or cell expansion under salt stress, but do not play a major role in plant tolerance to the osmotic stress component of soil salinity or drought. Here we report an additional sos mutant, sos6-1, which defines a locus essential for osmotic stress tolerance. sos6-1 plants are hypersensitive to salt stress and osmotic stress imposed by mannitol or polyethylene glycol in culture media or by water deficit in the soil. SOS6 encodes a cellulose synthase-like protein, AtCSLD5. Only modest differences in cell wall chemical composition could be detected, but we found that sos6-1 mutant plants accumulate high levels of reactive oxygen species (ROS) under osmotic stress and are hypersensitive to the oxidative stress reagent methyl viologen. The results suggest that SOS6/AtCSLD5 is not required for normal plant growth and development but has a critical role in osmotic stress tolerance and this function likely involves its regulation of ROS under stress. © 2010 Blackwell Publishing Ltd.

  8. The Arabidopsis Vacuolar Sorting Receptor1 Is Required for Osmotic Stress-Induced Abscisic Acid Biosynthesis

    KAUST Repository

    Wang, Zhen-Yu

    2014-11-21

    Osmotic stress activates the biosynthesis of the phytohormone abscisic acid (ABA) through a pathway that is rate limited by the carotenoid cleavage enzyme 9-cis-epoxycarotenoid dioxygenase (NCED). To understand the signal transduction mechanism underlying the activation of ABA biosynthesis, we performed a forward genetic screen to isolate mutants defective in osmotic stress regulation of the NCED3 gene. Here, we identified the Arabidopsis (Arabidopsis thaliana) Vacuolar Sorting Receptor1 (VSR1) as a unique regulator of ABA biosynthesis. The vsr1 mutant not only shows increased sensitivity to osmotic stress, but also is defective in the feedback regulation of ABA biosynthesis by ABA. Further analysis revealed that vacuolar trafficking mediated by VSR1 is required for osmotic stress-responsive ABA biosynthesis and osmotic stress tolerance. Moreover, under osmotic stress conditions, the membrane potential, calcium flux, and vacuolar pH changes in the vsr1 mutant differ from those in the wild type. Given that manipulation of the intracellular pH is sufficient to modulate the expression of ABA biosynthesis genes, including NCED3, and ABA accumulation, we propose that intracellular pH changes caused by osmotic stress may play a signaling role in regulating ABA biosynthesis and that this regulation is dependent on functional VSR1.

  9. Proline, glycine betaine, total phenolics and pigment contents in response to osmotic stress in maize seedlings

    Directory of Open Access Journals (Sweden)

    SAJJAD MOHARRAMNEJAD

    2015-12-01

    Full Text Available In order to evaluate the fresh weight, RWC, pigment content, total phenolics, proline and glycine betaine responses of maize inbred lines to osmotic stress, a factorial experiment was carried out under laboratory conditions with two maize inbred lines (B73 and MO17 and two osmotic stress levels induced by PEG (control and -0.6 MPa. Fresh weight significantly decreased under drought stress. On the basis of percent inhibition in fresh weight at the osmotic stress MO17 was ranked as tolerant (inhibition 45.30%, and B73 drought sensitive (inhibition more than 50%. Leaf relative water content (RWC was significantly decreased in both inbred lines under osmotic stress. The pigment concentrations were substantially declined in both maize inbreds under osmotic stressed conditions. However, this reduction was less in B73 than MO17. Osmoitc stress declined the levels of total phenolics in both maize inbreds. On the other hand, the osmotic stress markedly enhanced the levels of proline and glycine betaine in both maize inbreds, but this was more pronounced in MO17. The present results showed that osmotic stress retards the growth and some biochemical attributes of maize inbreds. In conclusion, the level of proline and glycine betaine in maize could improve drought tolerance.

  10. Electric charge, early universe and the Superstring Theories

    OpenAIRE

    Abbas, Afsar

    1999-01-01

    Very recently, it has been shown by the author that the Standard Model Higgs cannot be a physical particle. Here, on most general grounds it is established that as per the Standard Model there is no electric charge above the electro-weak phase transition temperature. Hence there was no electric charge present in the early universe. The Superstring Theories are flawed in as much as they are incompatible with this requirement. Hence the Superstring Theories are inconsistent with this basic stru...

  11. ELECTROKINETIC PHENOMENA : VII. RELATIONSHIP BETWEEN ELECTRIC MOBILITY, CHARGE, TITRATION CURVE, AND OPTICAL ROTATION OF PROTEIN.

    Science.gov (United States)

    Abramson, H A; Grossman, E B

    1932-05-20

    The specific rotation of egg albumin, gliadin, and gelatin (40 degrees C.) is discussed in connection with available data on (a) mobility, (b) titration curve, and (c) osmotic pressure. It seems likely that the change in specific rotation with pH of protein solutions is proportional to the change in net charge. PMID:19872669

  12. Distinguishing Field Effects from Charge Effects in the Optoelectronic Properties of Carbon Nanotube Films

    International Nuclear Information System (INIS)

    We have used charge-induced absorption to quantify the influence of injected charges on electro absorption measurements in single-wall carbon nanotube films. The interpretations of experimental measurements of X processes in nanotubes are simplified by taking into account the change in electron-electron interactions upon charge injection. Electro absorption spectra that are properly corrected for charge-induced effects show remarkable agreement with a simple Stark shift of the exciton transitions with no notable second-derivative contributions. Thus, distinguishing electric field effects from carrier density effects allows for a more rigorous calculation of exciton polarizability from electro absorption measurements, even in heterogeneous films. PACS: 78.67.Ch Nanotubes: optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures.

  13. Microchannel electrokinetics of charged analytes in buffered solutions near floating electrodes

    DEFF Research Database (Denmark)

    Andersen, Mathias Bækbo; Wolfcale, Trevor; Gregersen, Misha Marie; Pennathur, Sumita; Bruus, Henrik

    accurately predict such behavior in these flow regimes. Experimentally, using conventional fluorescence microscopy, we investigated the concentration gradient (as well as the associated electroosmosis, induced-charge electro-osmosis, and electrophoresis) of the charged analyte near the floating electrode as...

  14. Osmotic coefficients of water for thorium nitrate solutions at 25, 37, and 50oC

    International Nuclear Information System (INIS)

    Vapor pressure osmometry was used to measure osmotic coefficients of water for thorium nitrate solutions at 25, 37, and 50oC and at molalities up to 0.2 mol·kg-1. The data were fitted to three- and four-parameter equations containing limiting-law terms for a 4:1 electrolyte. The variation of the osmotic coefficients as a function of temperature was found to be small. The results are compared to published values for the osmotic coefficients. (author)

  15. Osmotic stress-regulated the expression of glutathione peroxidase 3 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    MIAO YuChen; GUO JingGong; LIU ErTao; LI Kun; DAI Jie; WANG PengCheng; CHEN Jia; SONG ChunPeng

    2007-01-01

    Gene expression of glutathione peroxidase 3 (ATGPX3) in response to osmotic stress was analyzed in Arabidopsis using ATGPX3 promoter-glucuronidase (GUS) transgenic plants. High levels of GUS expression were detected under osmotic stress in ATGPX3 promoter-GUS transgenic plants. Compared with the wild type, the growth and development of ATGPX3 mutants (atgpx3-1) were more sensitive to mannitol. In addition, the expression of RD29A, ABI1, ABI2 and RbohD in atgpx3-1 was induced by ABA stress. These results suggest that ATGPX3 might be involved in the signal transduction of osmotic stress.

  16. Posttranscriptional osmotic regulation of the sigma(s) subunit of RNA polymerase in Escherichia coli.

    OpenAIRE

    Muffler, A; Traulsen, D D; Lange, R. de; Hengge-Aronis, R

    1996-01-01

    The sigma(s) subunit of RNA polymerase (encoded by the rpoS gene) is a master regulator in a complex regulatory network that governs the expression of many stationary-phase-induced and osmotically regulated genes in Escherichia coli. rpoS expression is itself osmotically regulated by a mechanism that operates at the posttranscriptional level. Cells growing at high osmolarity already exhibit increased levels of sigma(s) during the exponential phase of growth. Osmotic induction of rpoS can be t...

  17. INVESTIGATION OF ULTRASOUND WAVES ON PRETREATMENT OF OSMOTIC DEHYDRATION OF CARROT SLICES

    OpenAIRE

    Tahmasebi, Soheila; Mirzaee, Somaye; Kaviyani, Mehdi; Tabrizi, Mahsa; Shariati, Mohammad

    2014-01-01

    In this study, carrot slices were put in glucose osmotic 50% at 1, 2 and 3 hr. Ultrasound waves, frequency 40 kH power 30 w/l, passed through container of osmotic solution and carrot slices. The results revealed that significant increasing of dry matter of sample by using ultrasound waves.pre osmotic time had a significant on dry material by increasing from 1to 3 hr.sample treated by ultrasound waves lost water faster and their final dry solid was significantly more than control (without ultr...

  18. Physicochemical characteristics of guava “Paluma” submitted to osmotic dehydration

    OpenAIRE

    Roselene Ferreira Oliveira; Lia Mara Moterlle; Edmar Clemente

    2014-01-01

    The aim of this work was to evaluate the conservation post process osmotic of guava stored temperature at 5oC. Guava (Psidium guajava L.), red variety “Paluma” minimally processed by mild osmotic dehydration, were packaged in polyethylene terephthalate (PET) and stored temperature at 5ºC. Non-treated guava, packed in PET trays, was used as control. The treatment used was osmotic dehydration in sucrose syrup at 60ºBrix and physicochemical determinations were pH, total soluble solids (TSS), tot...

  19. An electro-optic waveform interconnect based on quantum interference

    CERN Document Server

    Qin, Li-Guo; Gong, Shang-Qing

    2016-01-01

    The ability to modulate an optical field via an electric field is regarded as a key function of electro-optic interconnects, which are used in optical communications and information processing systems. One of the main required devices for such interconnects is the electro-optic modulator (EOM). Current EOM based on the electro-optic effect and the electro-absorption effect often is bulky and power inefficient due to the weak electro-optic properties of its constituent materials. Here we propose a new mechanism to produce an arbitrary-waveform EOM based on the quantum interference, in which both the real and imaginary parts of the susceptibility are engineered coherently with the superhigh efficiency. Based on this EOM, a waveform interconnect from the voltage to the modulated optical absorption is realised. We expect that such a new type of electro-optic interconnect will have a broad range of applications including the optical communications and network.

  20. Charged Condensation

    CERN Document Server

    Gabadadze, Gregory

    2008-01-01

    We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

  1. Enhanced methanol electro-oxidation reaction on Pt-CoOx/MWCNTs hybrid electro-catalyst

    International Nuclear Information System (INIS)

    Highlights: • Promoting effects of Cobalt oxide on methanol electro-oxidation over Pt/MWCNTs are investigated. • Higher activity, about 2.9 times, and enhanced stability are observed on Pt-CoOx/MWCNTs. • Electrochemical active surface area of Pt nanoparticles is significantly improved upon CoOx addition. • Bi-functional mechanism is facilitated in presence of CoOx. - Abstract: The electro-catalytic behavior of Pt-CoOx/MWCNTs in methanol electro-oxidation reaction (MOR) is investigated and compared to that of Pt/MWCNTs. The electro-catalysts were synthesized by an impregnation method using NaBH4 as the reducing agent. The morphological and physical characteristics of samples are examined by XRD, TEM, ICP and EDS techniques. In the presence of CoOx, Pt nanoparticles were highly distributed on the support with an average particle size of 2 nm, an obvious decrease from 5.1 nm for Pt/MWCNTs. Cyclic voltammetry, CO-stripping, Chronoamperometry, and electrochemical impedance spectroscopy (EIS) measurements are used to study the electrochemical behavior of the electro-catalysts. The results revealed a considerable enhancement in the oxidation kinetics of COads on Pt active sites by the participation of CoOx. Compared to Pt/MWCNTs, Pt-CoOx/MWCNTs sample has a larger electrochemical active surface area (ECSA) and higher electro-catalytic activity and stability toward methanol electro-oxidation. According to the results of cyclic voltammetry, the forward anodic peak current density enhances more than 89% at the optimum atomic ratio of Pt:Co = 2:1. Furthermore, inclusion of cobalt oxide species causes the onset potential of methanol electro-oxidation reaction to shift 84 mV to negative values compared to that on Pt/MWCNTs. Based on EIS data, dehydrogenation of methanol is the rate-determining step of MOR on both Pt/MWCNTs and Pt-CoOx/MWCNTs, at small overpotentials. However, at higher overpotentials, the oxidation of adsorbed oxygen-containing groups controls the

  2. Robust Position Control of Electro-mechanical Systems

    OpenAIRE

    Rong Mei; Mou Chen

    2013-01-01

    In this work, the robust position control scheme is proposed for the electro-mechanical system using the disturbance observer and backstepping control method. To the external unknown load of the electro-mechanical system, the nonlinear disturbance observer is given to estimate the external unknown load. Combining the output of the developed nonlinear disturbance observer with backstepping technology, the robust position control scheme is proposed for the electro-mechanical system. The stabili...

  3. A Mechanistic Approach to Elucidate Ethanol Electro-oxidation

    OpenAIRE

    TAPAN, Niyazi Alper

    2007-01-01

    In order to elucidate the mechanism of ethanol oxidation, a simple cylindrical diffusion-surface reaction was developed on a platinum disk electrode. An ethanol electro-oxidation mechanism was proposed, in which electrochemical reactions proceed without adsorption of any electro-oxidation products (C2 type) on the surface. After the simulation of the proposed mechanism, it was seen that the model can explain ethanol electro-oxidation behavior without any surface CO formation. The si...

  4. Globalization and Restructure of the Electro Power Sector

    OpenAIRE

    Vlatko Ecimovic

    2005-01-01

    In the last decade the wave of globalization reached the electro power sector, which commonly embraces about 30% of entire state economy. Therefore, consequences of restructure and liberalization of the electro power sector are many and remarkable and have an extensive impact on the economy. It is necessarily to have well goverment strategy and manage the electro power sector wisely, to efficiently implement that proceses. This writing represents an energy development strategy in Croatia as w...

  5. Electro-magnetic design and simulation of wall current monitor sensor for LEHIPA

    International Nuclear Information System (INIS)

    Beam diagnostic instruments are essential component of any accelerator. Wall current monitors (WCMs) are common beam diagnostic tools used for acquiring the temporal distribution of the charged particle bunches. This paper discusses the electro-magnetic design and simulation results of Wall current Monitor sensor being developed at Electronics Division, BARC with a bandwidth from 16.9 MHz to 30 GHz. As per the simulation results, output of the sensor for a 0.30A peak current bunched beam will be 0.8 Vpeak to peak. The simulations were carried out for Eigen modes, Particle In Cell (PIC) and Wake-field simulations using CST Microwave Studio Suite. (author)

  6. Electro-optical Bunch Length Monitor for FLUTE: Layout and Simulations

    OpenAIRE

    Borysenko, A.; Hertle, E.; Schuh, M.; Schwarz, M.; Wesolowski, P.; Steffen, Bernd; Hiller, N.; Judin, V.; Kehrer, B.; Marsching, S.; Müller, A. -S.; Nasse, M. J.; Rossmanith, R.; Ruprecht, R.

    2014-01-01

    A new compact linear accelerator FLUTE is currently under construction at Karlsruhe Institute of Technology (KIT) in collaboration with DESY and PSI. It aims at obtaining femtosecond electron bunches (~1fs - 300 fs) with a wide charge range (1 pC - 3 nC) and requires a precise bunch length diagnostic system. Here we present the layout of a bunch length monitor based on the electro-optic technique of spectral decoding using an Yb-doped fiber laser system (central wavelength 1030 nm) and a GaP ...

  7. Electro-optical characterization of MPPC detectors for the ASTRI Cherenkov telescope camera

    International Nuclear Information System (INIS)

    This work addresses a systematic and in-depth electro-optical characterization of the Multi-Pixel Photon Counter (MPPC) sensors constituting the camera detection system at the focal plane of the ASTRI telescope prototype. The paper reports the experimental results of a large set of measurements on the MPPC devices in order to provide a reliable qualification of the detector performance and evaluate its compliance with the telescope focal plane requirements. In particular, breakdown voltage, internal gain, dark count rate, cross-talk and extra-charge probability, and absolute photon detection efficiency measurements are performed on the basic sensor device unit as a function of the detector operating conditions

  8. Evaluating Pt-Ru/C mixtures as ethanol electro-oxidation catalysers

    Directory of Open Access Journals (Sweden)

    Bibian Alonso Hoyos

    2010-04-01

    Full Text Available This work studies ethanol electro-catalytic oxidation by cyclic voltametry in sulphuric acid solutions at different temperatures and concetrations, using platinum.rutenium mixtures supported in vitreous carbon as catalysers. The results indicate that ethanol oxidation in theses electrodes is irreversible, has slow kinetics, is controlled by charge transfer and is brought about by a bi-functional reaction mechanism, this being ethanol adsorption on platinum atoms and additional oxidation of specties adsorbed in the presence of platinum and retenium oxides. Experimental results show increased catalytic activity with electrodes, followed by reduced activity for electrodes having a greater quantity of rutenium.

  9. Dynamic mesh refinement for discrete models of jet electro-hydrodynamics

    CERN Document Server

    Lauricella, Marco; Pisignano, Dario; Succi, Sauro

    2015-01-01

    Nowadays, several models of unidimensional fluid jets exploit discrete element methods. In some cases, as for models aiming at describing the electrospinning nanofabrication process of polymer fibers, discrete element methods suffer a non constant resolution of the jet representation. We develop a dynamic mesh-refinement method for the numerical study of the electro-hydrodynamic behavior of charged jets using discrete element methods. To this purpose, we import ideas and techniques from the string method originally developed in the framework of free-energy landscape simulations. The mesh-refined discrete element method is demonstrated for the case of electrospinning applications.

  10. Comparative study of chemo-electro-mechanical transport models for an electrically stimulated hydrogel

    International Nuclear Information System (INIS)

    The main objective of this work is to introduce a new expression for the hydrogel’s hydration for use within the Poisson Nernst–Planck chemo electro mechanical (PNP CEM) transport models. This new contribution to the models support large deformation by considering the higher order terms in the Green–Lagrangian strain tensor. A detailed discussion of the CEM transport models using Poisson Nernst–Planck (PNP) and Poisson logarithmic Nernst–Planck (PLNP) equations for chemically and electrically stimulated hydrogels will be presented. The assumptions made to simplify both CEM transport models for electric field application in the order of 0.833 kV m−1 and a highly diluted electrolyte solution (97% is water) will be explained. This PNP CEM model has been verified accurately against experimental and numerical results. In addition, different definitions for normalizing the parameters are used to derive the dimensionless forms of both the PNP and PLNP CEM. Four models, PNP CEM, PLNP CEM, dimensionless PNP CEM and dimensionless PNLP CEM transport models were employed on an axially symmetric cylindrical hydrogel problem with an aspect ratio (diameter to thickness) of 175:3. The displacement and osmotic pressure obtained for the four models are compared against the variation of the number of elements for finite element analysis, simulation duration and solution rate when using the direct numerical solver. (papers)

  11. Role of electro-osmosis in the impedance response of microchannel-nanochannel interfaces.

    Science.gov (United States)

    Schiffbauer, Jarrod; Yossifon, Gilad

    2012-11-01

    The influence of net fluid flow on the low-frequency ac response of a microchannel-nanochannel interface under dc bias is studied theoretically using a simple 1D model based on the Poisson-Nernst-Planck-Stokes equations. The model describes cross-sectional averaged transport wherein the electro-osmotic flow is controlled by the magnitude of the dc bias and captures essential features of the problem related to the micro-nano interface, specifically geometric focusing effects and nanochannel control of the net fluid flow. This model predicts behavior which differs from that predicted by a purely electrodiffusive formulation. The high-frequency edge of the Warburg branch of the complex impedance plot has a slope which deviates from the π/4 Warburg value, decreasing with increasing bias, and there are corresponding changes in the overall phase as seen in the Bode plots. This can be attributed to a streaming contribution to the capacitive reactance of the device as well an increase in the conductance of the depleted region, both due to net fluid flow. The increase in conductance, corresponding to reduced interfacial depletion, also permits dc currents above the classical electrodiffusive limit. PMID:23214878

  12. Oral push-pull osmotic pumps of pentazocine hydrochloride: Development and evaluation

    Directory of Open Access Journals (Sweden)

    Mishra B

    2006-01-01

    Full Text Available The present study was aimed to formulate and evaluate oral osmotic pumps of pentazocine HCl that are expected to deliver the drug as solution for prolonged period of time with reduced frequency of drug administration and reduced side effects. Push-Pull osmotic pumps of pentazocine HCl were prepared using different formulation variables like diameter of pores, presence of surfactant in formulation core, addition of osmopolymer pectin and presence/absence of water-soluble polymer (carboxymethylcellulose sodium. Fabricated osmotic pumps were evaluated for weight variation, coating thickness, pore diameter, drug content and in vitro release studies. Release rates were found to be independent of size of pores, agitation intensity, and pH of the release medium. The presence of surfactant, water-soluble polymer and osmopolymer (pectin affected the drug release significantly. Almost all the osmotic pumps gave controlled and prolonged drug release profiles beyond 2 h of lag phase.

  13. Selection and characterization of tomato plants for osmotic stress tolerance derived from a gamma ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kwon Kyoo; Jung, Yu Jin [Hankyong National University, Anseong (Korea, Republic of)

    2010-09-15

    The present study has been performed to select the osmotic tolerant lines using polyethylene glycol (PEG 6000)through an in vitro and in vivo mutagensis with a gamma-ray. During the screening, we selected three mutant lines that seemed to confer elevated osmotic tolerance in high concentrations of PEG 6000. Fruits of these mutants (Os-HK101, Os-HK102 and Os-HK103) were those of the wild type. Also the chlorophyll contents were few decreased more in the three mutant lines than the WT plants. Our results suggest that the Os-HK101 is characterized as osmotic stress tolerance considering the sugar concentration and lycopine content. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected osmotic resistant lines.

  14. The osmotic second virial coefficient and the Gibbs-McMillan-Mayer framework

    DEFF Research Database (Denmark)

    Mollerup, J.M.; Breil, Martin Peter

    2009-01-01

    . The independent variables of the solvents are temperature, pressure, and chemical potentials. The derivatives in the Gibbs-McMillan-Mayer framework are transformed into derivatives in the Gibbs framework. This offers the possibility for an interpretation and correlation of the osmotic second virial......The osmotic second virial coefficient is a key parameter in light scattering, protein crystallisation. self-interaction chromatography, and osmometry. The interpretation of the osmotic second virial coefficient depends on the set of independent variables. This commonly includes the independent...... is an independent variable. A Taylor expansion is applied to the osmotic pressure of a solution where one of the solutes is a small molecule, a salt for instance, that equilibrates between the two phases. Other solutes are retained. Solvents are small molecules that equilibrate between the two phases...

  15. Electro-optic frame photography with pulsed ruby illumination

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, L.L.; Muelder, S.A.; Rivera, A.T.; Dunmire, J.L.; Breithaupt, R.D.

    1992-11-11

    By combining the attributes of electro-optic shuttering and pulsed laser illumination in a large format camera system, we have developed a multi-frame image converter camera with a laser illuminator that produces sequential photographs of fast phenomena with very high resolution. The combination of the large size image plane (75 mm), short exposure time per frame (minimum 12--15 ns), and monochromatic laser illumination provides clear, sharp, front-lit images of surfaces and shapes with no degradation by luminous air shocks or motion blur. The unique modular design of the camera and the laser allow for a variety of configurations and applications. The current camera system produces eight independent pictures or four stereo pairs. A Q-switched ruby laser with multiple pulse capability provides individual illumination for each frame. This system has photographed a variety of fast phenomena including the first stereo sequential photographs of the initial formation and early time history of high velocity shaped-charge jets.

  16. Electro-coagulation-flotation process for algae removal.

    Science.gov (United States)

    Gao, Shanshan; Yang, Jixian; Tian, Jiayu; Ma, Fang; Tu, Gang; Du, Maoan

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density=1 mA/cm(2), pH=4-7, water temperature=18-36 degrees C, algae density=0.55 x 10(9)-1.55 x 10(9) cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m(3). The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view. PMID:20042280

  17. Electro-coagulation-flotation process for algae removal

    International Nuclear Information System (INIS)

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density = 1 mA/cm2, pH = 4-7, water temperature = 18-36 deg. C, algae density = 0.55 x 109-1.55 x 109 cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m3. The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

  18. Electro-coagulation-flotation process for algae removal

    Energy Technology Data Exchange (ETDEWEB)

    Gao Shanshan, E-mail: luck81919@hotmail.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, Hei Longjiang (China); Yang Jixian; Tian Jiayu; Ma Fang; Tu Gang; Du Maoan [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin 150090, Hei Longjiang (China)

    2010-05-15

    Algae in surface water have been a long-term issue all over the world, due to their adverse influence on drinking water treatment process as well as drinking water quality. The algae removal by electro-coagulation-flotation (ECF) technology was investigated in this paper. The results indicated that aluminum was an excellent electrode material for algae removal as compared with iron. The optimal parameters determined were: current density = 1 mA/cm{sup 2}, pH = 4-7, water temperature = 18-36 deg. C, algae density = 0.55 x 10{sup 9}-1.55 x 10{sup 9} cells/L. Under the optimal conditions, 100% of algae removal was achieved with the energy consumption as low as 0.4 kWh/m{sup 3}. The ECF performed well in acid and neutral conditions. At low initial pH of 4-7, the cell density of algae was effectively removed in the ECF, mainly through the charge neutralization mechanism; while the algae removal worsened when the pH increased (7-10), and the main mechanism shifted to sweeping flocculation and enmeshment. The mechanisms for algae removal at different pH were also confirmed by atomic force microscopy (AFM) analysis. Furthermore, initial cell density and water temperature could also influence the algae removal. Overall, the results indicated that the ECF technology was effective for algae removal, from both the technical and economical points of view.

  19. Analysis of low pressure electro-positive and electro-negative rf plasmas with Monte Carlo method

    OpenAIRE

    M. ARDEHALI

    1998-01-01

    Particle-in-cell/Monte Carlo technique is used to simulate low pressure electro-negative and electro-positive plasmas at a frequency of 10 MHz. The potential, electric field, electron and ion density, and currents flowing across the plasma are presented. To compare the physical properties of the electro-positive gas with those of an electro-negative gas, the input voltage was decreased from 1000 Volts to 350 Volts. The simulation results indicate that the introduction of negative ions induces...

  20. Osmotic Pressure of Aqueous Chondroitin Sulfate Solution: A Molecular Modeling Investigation

    OpenAIRE

    Bathe, Mark; Rutledge, Gregory C.; Grodzinsky, Alan J.; TIDOR, BRUCE

    2005-01-01

    The osmotic pressure of chondroitin sulfate (CS) solution in contact with an aqueous 1:1 salt reservoir of fixed ionic strength is studied using a recently developed coarse-grained molecular model. The effects of sulfation type (4- vs. 6-sulfation), sulfation pattern (statistical distribution of sulfate groups along a chain), ionic strength, CS intrinsic stiffness, and steric interactions on CS osmotic pressure are investigated. At physiological ionic strength (0.15 M NaCl), the sulfation typ...

  1. The Osmotic Coefficient of Rod-like Polyelectrolytes: Computer Simulation, Analytical Theory, and Experiment

    OpenAIRE

    Deserno, M.; Holm, C; Blaul, J.; Ballauff, M.; Rehahn, M.

    2001-01-01

    The osmotic coefficient of solutions of rod-like polyelectrolytes is considered by comparing current theoretical treatments and simulations to recent experimental data. The discussion is restricted to the case of monovalent counterions and dilute, salt-free solutions. The classical Poisson-Boltzmann solution of the cell model correctly predicts a strong decrease in the osmotic coefficient, but upon closer look systematically overestimates its value. The contribution of ion-ion-correlations ar...

  2. Irreversible injury of isolated adult rat myocytes. Osmotic fragility during metabolic inhibition.

    OpenAIRE

    Ganote, C. E.; Vander Heide, R. S.

    1988-01-01

    Isolated myocytes can be established as a valid model for studying changes in cytoskeletal proteins during the development of irreversible injury only if isolated cells develop lesions similar to those that occur during irreversible injury to intact hearts, specifically osmotic fragility and subsarcolemmal blebs. In the first experiment, isolated cells were irreversibly injured by metabolic inhibition with 5 mM Iodoacetic acid (IAA) and 6 mM amobarbital (Amy). Osmotic fragility of control and...

  3. Osmotic Stress Induces Oxidative Cell Damage to Rhesus Macaque Spermatozoa1

    OpenAIRE

    McCarthy, Megan J.; Baumber, Julie; Kass, Philip H.; Meyers, Stuart A.

    2009-01-01

    Cryopreservation introduces extreme temperature and osmolality changes that impart lethal and sublethal effects on spermatozoa survival. Additionally, evidence indicates that the osmotic stress induced by cryopreservation causes oxidative stress to spermatozoa as well. Our objective was to determine the effect of reactive oxygen species (ROS) on rhesus macaque (Macaca mulatta) sperm function and to determine whether osmotic stress elicits the production of ROS. In the first experiment, the xa...

  4. The Na/K pump, Cl ion, and osmotic stabilization of cells

    OpenAIRE

    Armstrong, Clay M.

    2003-01-01

    An equation for membrane voltage is derived that takes into account the electrogenicity of the Na/K pump and is valid dynamically, as well as in the steady state. This equation is incorporated into a model for the osmotic stabilization of cells. The results emphasize the role of the pump and membrane voltage in lowering internal Cl− concentration, thus making osmotic room for vital substances that must be sequestered in the cell.

  5. Effect of process variables on the osmotic dehydration of star-fruit slices

    OpenAIRE

    Camila Dalben Madeira Campos; Ana Carla Kawazoe Sato; Renata Valeriano Tonon; Míriam Dupas Hubinger; Rosiane Lopes da Cunha

    2012-01-01

    The objective of this work was to study the effect of blanching and the influence of temperature, solution concentration, and the initial fruit:solution ratio on the osmotic dehydration of star-fruit slices. For blanching, different concentrations of citric and ascorbic acids were studied. The samples immersed in 0.75% citric acid presented little variation in color in relation to the fresh star-fruit. Osmotic dehydration was carried out in an incubator with orbital shaking, controlled temper...

  6. Proteomic Analysis of Erythritol-Producing Yarrowia lipolytica from Glycerol in Response to Osmotic Pressure.

    Science.gov (United States)

    Yang, Li-Bo; Dai, Xiao-Meng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2015-07-01

    Osmotic pressure is a critical factor for erythritol production with osmophilic yeast. Protein expression patterns of an erythritol-producing yeast, Yarrowia lipolytica, were analyzed to identify differentially-expressed proteins in response to osmotic pressure. In order to analyze intracellular protein levels quantitatively, two-dimensional gel electrophoresis was performed to separate and visualize the differential expression of the intracellular proteins extracted from Y. lipolytica cultured under low (3.17 osmol/kg) and high (4.21 osmol/kg) osmotic pressures. Proteomic analyses allowed identification of 54 differentially-expressed proteins among the proteins distributed in the range of pI 3-10 and 14.4-97.4 kDa molecular mass between the osmotic stress conditions. Remarkably, the main proteins were involved in the pathway of energy, metabolism, cell rescue, and stress response. The expression of such enzymes related to protein and nucleotide biosynthesis was inhibited drastically, reflecting the growth arrest of Y. lipolytica under hyperosmotic stress. The improvement of erythritol production under high osmotic stress was due to the significant induction of a range of crucial enzymes related to polyols biosynthesis, such as transketolase and triosephosphate isomerase, and the osmotic stress responsive proteins like pyridoxine-4-dehydrogenase and the AKRs family. The polyols biosynthesis was really related to an osmotic response and a protection mechanism against hyperosmotic stress in Y. lipolytica. Additionally, the high osmotic stress could also induce other cell stress responses as with heat shock and oxidation stress responses, and these responsive proteins, such as the HSPs family, catalase T, and superoxide dismutase, also had drastically increased expression levels under hyperosmotic pressure. PMID:25737116

  7. The osmotic stress response of split influenza vaccine particles in an acidic environment

    OpenAIRE

    Choi, Hyo-Jick; Kim, Min-Chul; Kang, Sang-Moo; Montemagno, Carlo D.

    2013-01-01

    Oral influenza vaccine provides an efficient means of preventing seasonal and pandemic disease. In this work, the stability of envelope-type split influenza vaccine particles in acidic environments has been investigated. Owing to the fact that hyper-osmotic stress can significantly affect lipid assembly of vaccine, osmotic stress-induced morphological change of split vaccine particles, in conjunction with structural change of antigenic proteins, was investigated by the use of stopped-flow lig...

  8. Osmotic dehydration of red cabbage in sugar beet molasses: Mass transfer kinetics

    OpenAIRE

    Filipčev Bojana V.; Lević Ljubinko B.; Koprivica Gordana B.; Mišljenović Nevena M.; Kuljanin Tatjana A.

    2009-01-01

    The paper describes a study of osmotic dehydration of red cabbage in sugar beet molasses of different concentrations (40, 60 and 80%) at 50°C and under atmospheric pressure. The best results were obtained at the sugar beet molasses of 80% as an osmotic medium. The most important kinetic parameters of the process were determined: water loss, solid uptake, weight reduction, normalized solid content and normalized moisture content. The kinetic parameters were determined after 1, 3 and 5 hours. M...

  9. FORMULATION AND EVALUATION OF CONTROLLED POROSITY OSMOTIC DRUG DELIVERY SYSTEM OF METOPROLOL SUCCINATE

    OpenAIRE

    Hardik Patel* and M. M. Patel

    2012-01-01

    Controlled porosity osmotic tablet of metoprolol succinate prepared and evaluated in this study. Metoprolol succinate is very high soluble drug, so complete drug release obtained very fast. It is difficult to formulate osmotic tablet of Metoprolol succinate which gives drug release up to 24 hr at zero order. To get desired dissolution profile various formulation parameters like osmogen concentration, level of weight gain and level of pore former concentration were studied. Hypromellose was ad...

  10. Development and Optimization of Osmotically Controlled Asymmetric Membrane Capsules for Delivery of Solid Dispersion of Lycopene

    OpenAIRE

    2014-01-01

    The aim of the present investigation is to develop and statistically optimize the osmotically controlled asymmetric membrane capsules of solid dispersion of lycopene. Solid dispersions of lycopene with β-cyclodextrin in different ratios were prepared using solvent evaporation method. Solubility studies showed that the solid dispersion with 1 : 5 (lycopene : β-cyclodextrin) exhibited optimum solubility (56.25 mg/mL) for osmotic controlled delivery. Asymmetric membrane capsules (AMCs) were prep...

  11. Desorption electro-flow focusing ionization of explosives and narcotics for ambient pressure mass spectrometry.

    Science.gov (United States)

    Forbes, Thomas P; Brewer, Tim M; Gillen, Greg

    2013-10-01

    Desorption electro-flow focusing ionization (DEFFI), a desorption-based ambient ion source, was developed, characterized, and evaluated as a possible source for field deployable ambient pressure mass spectrometry (APMS). DEFFI, based on an electro-flow focusing system, provides a unique configuration for the generation of highly charged energetic droplets for sample analysis and ionization. A concentrically flowing carrier gas focuses the liquid emanating from a capillary through a small orifice, generating a steady fluid jet. An electric field is applied across this jet formation region, producing high velocity charged droplets that impinge on an analyte laden surface. This configuration separates the jet charging region from the external environment, eliminating detrimental effects from droplet space charge or target surface charging. The sample desorption and ionization processes operate similar to desorption electrospray ionization (DESI). DEFFI demonstrated strong signal intensities and improved signal-to-noise ratios in both positive and negative mode mass spectrometry for narcotics, i.e., cocaine, and explosives, i.e., cyclotrimethylenetrinitramine (RDX), respectively. A characterization of DEFFI ionization mechanisms identified operation regimes of both electrospray and corona discharge based analyte ionization, as well as limitations in overall signal. In addition, the DEFFI response was directly compared to DESI-MS under similar operating conditions. This comparison established a wider and more stable optimal operating range, while requiring an order of magnitude lower applied gas pressure and applied potential for DEFFI than DESI. These reductions are due to the physical mode of jet formation and geometric configuration differences between DEFFI and DESI, pointing to a potential benefit of DEFFI-MS for field implementation. PMID:23923127

  12. Electro-optic imaging Fourier transform spectrometer

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Znod, Hanying (Inventor)

    2009-01-01

    An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.

  13. Electro-optical fuel pin identification system

    International Nuclear Information System (INIS)

    A prototype Electro-Optical Fuel Pin Identification System referred to as the Fuel Pin Identification System (FPIS) has been developed by the Hanford Engineering Development Laboratory (HEDL) in support of the Fast Flux Test Facility (FFTF) presently under construction at HEDL. The system is designed to remotely read an alpha-numeric identification number that is roll stamped on the top of the fuel pin end cap. The prototype FPIS consists of four major subassemblies: optical read head, digital compression electronics, video display, and line printer

  14. Electro-decontamination of cementitious materials

    International Nuclear Information System (INIS)

    The end of operations in nuclear facilities is followed by various decontamination and decommissioning operations. Similar to other electrochemical techniques such as re-alkalinisation and chloride extraction, an electrokinetic remediation process is being developed as a specific method for deeply contaminated concrete structures. Two cements, an ordinary Portland and a 30% slag cement, have been chosen for the conducted work.Mortars and concretes are contaminated by adding non-radioactive cesium in the batch water, cesium being a representative specie of deep encountered contaminants. The conducted experimental and numerical work have focused on three main aspects: characterizing and understanding the cesium transport mechanisms, assessing the electro-remediation process at lab-scale and evaluating the real scale constraints. Using existing knowledge of chloride transport mechanisms, experiments have been conducted to characterize the cesium interactions with cementitious phase and ionic transport in saturated materials. A numerical model have then been developed to describe the cesium transport, taking into account the ionic activity coefficients and interactions with solid phases. Indeed, lab-scale experiments have demonstrated that electro-remediation reduced to 20-50% the initially contained cesium after a three weeks treatment. Treated samples analysis confirmed that deeply diffused cesium is migrating to the surface. Moreover, conducted experiments showed the consistency between the different materials properties, applied currents and decontamination efficiency. A comparative analysis of experiments carried on samples with different shapes, formulations and contamination modes helped assessing and optimizing the process efficiency for various continuous and variable applied currents. Finally, electro-remediation experiments have also been carried on 1m2 concrete slabs. Liquid catholyte and anolyte solutions are replaced by alumina gels and cellulose pastes

  15. Interaction modes between asymmetrically and oppositely charged rods

    Science.gov (United States)

    Antila, Hanne S.; Van Tassel, Paul R.; Sammalkorpi, Maria

    2016-02-01

    The interaction of oppositely and asymmetrically charged rods in salt—a simple model of (bio)macromolecular assembly—is observed via simulation to exhibit two free energy minima, separated by a repulsive barrier. In contrast to similar minima in the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the governing mechanism includes electrostatic attraction at large separation, osmotic repulsion at close range, and depletion attraction near contact. A model accounting for ion condensation and excluded volume is shown to be superior to a mean-field treatment in predicting the effect of charge asymmetry on the free-energy profile.

  16. Active Osmotic Exchanger for Efficient Nanofiltration Inspired by the Kidney

    Science.gov (United States)

    Marbach, Sophie; Bocquet, Lydéric

    2016-07-01

    In this paper, we investigate the physical mechanisms underlying one of the most efficient filtration devices: the kidney. Building on a minimal model of the Henle loop—the central part of the kidney filtration—we investigate theoretically the detailed out-of-equilibrium fluxes in this separation process in order to obtain absolute theoretical bounds for its efficiency in terms of separation ability and energy consumption. We demonstrate that this separation process operates at a remarkably small energy cost as compared to traditional sieving processes while working at much smaller pressures. This unique energetic efficiency originates in the double-loop geometry of the nephron, which operates as an active osmotic exchanger. The principles for an artificial-kidney-inspired filtration device could be readily mimicked based on existing soft technologies to build compact and low-energy artificial dialytic devices. Such a "kidney on a chip" also points to new avenues for advanced water recycling, targeting, in particular, sea-water pretreatment for decontamination and hardness reduction.

  17. Rationalization of Sucrose Solution Using During the Fruit Osmotic Dehydration

    Directory of Open Access Journals (Sweden)

    Mirko Babić

    2009-12-01

    Full Text Available The model of sustainable energy production of dried fruit conducted by using combined technology – the model that has been developed at the Faculty of Agriculture in Novi Sad – includes osmotic dehydration of fruit in sucrose solution. During the process of dehydration the moisture content of the solution is increased due to mass transfer of moisture from fruit. This article examines different models of recycling and concentrating of the solution. Thus, the model for concentrating of the solution has been chosen according to this analysis, and it has been applied within its own technology. Evaporators of the low temperature solution have been used and they are based on the solar energy source. Two types of devices have been made on the basis of the heating process of evaporating. One type is filled with the stainless steel shavings, while the other type is based on the fillings by plates. The paper presents the evaluation model of the benefits of this concentrating manner as well as the evaluation criterion of the evaporators’ fillings types. The energy support used here was an original solar air heater of semi-concentrated type.

  18. Sandwich-structured hollow fiber membranes for osmotic power generation

    KAUST Repository

    Fu, Feng Jiang

    2015-11-01

    In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

  19. Osmotic shock as alternative method to control Acanthaster planci

    Institute of Scientific and Technical Information of China (English)

    Jairo Rivera-Posada; Leigh Owens

    2014-01-01

    Objective:To test six osmotic stressors as alternative methods to control Acanthaster planci (A. planci) outbreaks by exploiting their incapacity to tolerate drastic changes in osmolarity. Finding more effective ways to control A. planci outbreaks is one of the most immediate and effective ways by which to reverse rapid declines in the abundance of live coral cover in the Indo-Pacific. Methods: A total of 10 mL of each of the following chemicals: sodium chloride, ethylenediaminetetraacetic acid, sodium carbonate, sodium cholate, sodium deoxycholate, urea and mannitol were injected into individual healthy sea stars to examine which chemicals induced disease and death. Results:Four out of six chemicals used in this study induced disease. Sodium chloride, sodium cholate, sodium deoxycholate and ethylenediaminetetraacetic acid are capable of inducing death in injected sea stars offering an alternative option to control A. planci outbreaks. Conclusions: Hyperosmotic stress is a viable alternative to control A. planci outbreaks as massive cell death results when acute hypertonicity exceeds a certain level.

  20. Miniature osmotic actuators for controlled maxillofacial distraction osteogenesis

    Science.gov (United States)

    Li, Yu-Hsien; Su, Yu-Chuan

    2010-06-01

    We have successfully demonstrated miniature actuators that are capable of converting chemical potential directly into steady mechanical movements for maxillofacial distraction osteogenesis. Pistons and diaphragms powered by osmosis are employed to provide the desired linear and volumetric displacements for bone distraction and potentially the release of bone morphogenetic proteins, respectively. The cylindrical-shaped miniature actuators are composed of polymeric materials and fabricated by molding and assembly processes. In the prototype demonstration, vapor-permeable thermoplastic polyurethane was employed as the semi-permeable material. 3 cm long actuators with piston and diaphragm radii of 1 mm and 500 µm, respectively, were fabricated and characterized. The maximum distraction force from the piston-type actuator is found to be 6 N while the piston travels at a constant velocity of 32 µm h-1 (or 0.77 mm/day) for about 1 week. Meanwhile, the release rate from the diaphragm-type actuator is measured to be constant, 0.15 µl h-1 (or 3.6 µl/day), throughout the experiment. Moreover, the sizes and output characteristics of the self-regulating actuators could readily be tailored to realize optimal distraction rate, rhythm and osteogenic activity. As such, the demonstrated miniature osmotic actuators could potentially serve as versatile apparatuses for maxillofacial distraction osteogenesis and fulfill the needs of a variety of implantable and biomedical applications.

  1. Osmotically induced cytosolic free Ca(2+) changes in human neutrophils.

    Science.gov (United States)

    Morris, M R; Doull, I J; Hallett, M B

    2001-02-01

    Cytosolic free Ca(2+) concentration in neutrophils was measured by ratiometric fluorometry of intracellular fura2. Increasing the extracellular osmolarity, by either NaCl (300-600 mM) or sucrose (600-1200 mM), caused a rise in cytosolic free Ca(2+) (Delta(max) approximately equal to 600 nM). This was not due to cell lysis as the cytosolic free Ca(2+) concentration was reversed by restoration of isotonicity and a second rise in cytosolic free Ca(2+) could be provoked by repeating the change in extracellular osmolarity. Furthermore, the rise in cytosolic free Ca(2+) concentration occurred in the absence of extracellular Ca(2+), demonstrating that release of intracellular fura2 into the external medium did not occur. The osmotically-induced rise in cytosolic free Ca(2+) was not inhibited by either the phospholipase C-inhibitor U73122, or the microfilament inhibitor cytochalasin B, suggesting that neither signalling via inositol tris-phosphate or the cytoskeletal system were involved. However, the rise in cytosolic free Ca(2+) may have resulted from a reduction in neutrophil water volume in hyperosmotic conditions. As these rises in cytosolic Ca(2+) (Delta(max) approximately equal to 600 nM) were large enough to provoke changes in neutrophil activity, we propose that conditions which removes cell water may similarly elevate cytosolic free Ca(2+) to physiologically important levels. PMID:11341979

  2. The effects of osmotic stress on human platelets.

    Science.gov (United States)

    Armitage, W J; Parmar, N; Hunt, C J

    1985-05-01

    The effect of osmotic stress on human platelets was investigated at 0, 25, and 37 degrees C. The osmolality of the suspending plasma was decreased by adding water or increased by adding sodium chloride or sucrose. After 5 min, isotonicity was restored by dilution with an excess of isotonic phosphate-buffered saline. After centrifugation, the platelets were resuspended in autologous plasma and then incubated for 1 hr at 37 degrees C before assaying the active transport of 5-hydroxytryptamine (5-HT) and the hypotonic stress response. Anisosmotic conditions had a greater effect on the extent of volume reversal in the hypotonic stress test than on 5-HT uptake. At 25 degrees C, only moderate degrees of hypotonicity (0.25 osmol/kg) or hypertonicity (0.59 osmol/kg) were sufficient to depress the hypotonic stress response. In general, platelets tolerated departures from isotonic conditions better at 0 degree C than at the higher temperatures. Furthermore, at 0 and 25 degrees C approximately equiosmolal concentrations of sucrose and sodium chloride depressed the hypotonic stress response to similar extents, but at 37 degrees C high osmolalities (greater than 2 osmol/kg) were tolerated better when the additive was sucrose than when it was sodium chloride. Platelets shrank when subjected to hyperosmotic conditions, but their discoid shape and the peripheral band of microtubules were maintained. PMID:3980588

  3. Miniature osmotic actuators for controlled maxillofacial distraction osteogenesis

    International Nuclear Information System (INIS)

    We have successfully demonstrated miniature actuators that are capable of converting chemical potential directly into steady mechanical movements for maxillofacial distraction osteogenesis. Pistons and diaphragms powered by osmosis are employed to provide the desired linear and volumetric displacements for bone distraction and potentially the release of bone morphogenetic proteins, respectively. The cylindrical-shaped miniature actuators are composed of polymeric materials and fabricated by molding and assembly processes. In the prototype demonstration, vapor-permeable thermoplastic polyurethane was employed as the semi-permeable material. 3 cm long actuators with piston and diaphragm radii of 1 mm and 500 µm, respectively, were fabricated and characterized. The maximum distraction force from the piston-type actuator is found to be 6 N while the piston travels at a constant velocity of 32 µm h−1 (or 0.77 mm/day) for about 1 week. Meanwhile, the release rate from the diaphragm-type actuator is measured to be constant, 0.15 µl h−1 (or 3.6 µl/day), throughout the experiment. Moreover, the sizes and output characteristics of the self-regulating actuators could readily be tailored to realize optimal distraction rate, rhythm and osteogenic activity. As such, the demonstrated miniature osmotic actuators could potentially serve as versatile apparatuses for maxillofacial distraction osteogenesis and fulfill the needs of a variety of implantable and biomedical applications.

  4. Pulsatile arginine vasopressin release from the rat hypothalamo neurohypophyseal system during osmotic stimulation.

    Directory of Open Access Journals (Sweden)

    Ohno,Norihito

    1981-06-01

    Full Text Available Arginine vasopressin (AVP was released in vitro in a pulsatile pattern from the hypothalamo-neurohypophyseal system (HNS and from the hypothalamus during continuous hyperosmotic stimuli with NaCl or fructose. No significant difference was found in the AVP pulse frequency between the two kinds of hyperosmotic agents. AVP was released from the HNS in a dose-related manner under NaCl stimulation. When the neural lobe was stimulated with NaCl or fructose, a clear AVP pulse pattern was not apparent. Urea failed to evoke a significant AVP release from the neural lobe or HNS. A stepwise increase in NaCl stimulation from 5 to 25 mEq induced a AVP response from the HNS and hypothalamus similar to that under constant stimulation at 25 mEq NaCl. This phenomenon was also found with fructose or sucrose. These results suggest that AVP release from the HNS during continuous osmotic stimulation has a pulsatile pattern regardless of the hyperosmotic substance or osmotic pressure. This AVP release accurately reflects the physiological function of the hypothalamus without modulation in the neural lobe. These results also suggest that the total amount of AVP was related to the osmotic pressure or the osmotic substance but that the frequency of the pulse release was not, moreover, that the AVP release depends not only on the absolute osmotic pressure, but also on the changing rate of osmotic pressure.

  5. Effect on effective diffusion coefficients and investigation of shrinkage during osmotic dehydration of apricot

    Energy Technology Data Exchange (ETDEWEB)

    Togrul, Inci Turk; Ispir, Ayse [Firat University, Engineering Faculty, Department of Chemical Engineering, 23279 Elazig (Turkey)

    2007-10-15

    This article represents the results of the variation in density and shrinkage of apricots during its osmotic dehydration. Shrinkage was investigated by means of dimensionless volume, diameter and length. Various osmotic agents such as sucrose, glucose, fructose, maltodextrin and sorbitol were used. It was found that the shrinkage of apricots could be well correlated with the moisture content of the sample during osmotic dehydration. The relationship between dimensionless parameters and moisture content was investigated by using eight non-linear models for each osmotic agent. It was find that the following proposed model can be confidently use for explaining the effect of shrinkage during osmotic dehydration of apricots.V/V{sub 0},D/D{sub 0},L/L{sub 0},{rho}/{rho}{sub 0}=a+b. exp (cX)+d. exp (e.X{sup f})In addition, the osmotic dehydration kinetics of apricots with and without shrinkage was studied. The effective diffusivities calculated from the diffusional model with and without shrinkage varied from 10.342 x 10{sup -9} m{sup 2}/s to 5.139 x 10{sup -9} and from 1.755 x 10{sup -10} and 0.767 x 10{sup -10} m{sup 2}/s, respectively. (author)

  6. EFFECT OF TABLET FORMULATION VARIABLES ON TRAMADOL HCL ELEMENTARY OSMOTIC PUMP TABLET

    Directory of Open Access Journals (Sweden)

    Basani Gavaskar

    2010-12-01

    Full Text Available Osmotic drug delivery system utilize osmotic pressure as a energy source and driving force for delivery of drugs, pH presence of food under physiological factors may affect drug release from conventional controlled release system (Matrices and reservoirs, where as drug release from osmotic system is independent of these factors to a large extent. The aim of the current study was to formulate elementary osmotic pump tablets of water soluble Tramadol HCl. Formulation were prepared based on wet granulation method, coated with cellulose acetate solution containing varying amount of Dibutylphthalate (DBP, and Polyethylene glycol 400 (PEG-400. Drug release from the osmotic drug delivery system was studied using USP Type I Paddle type apparatus. The excipients of physio-chemical property of the drug were determined by DSC (Differential scanning calorimetry. The optimized formulation was subjected to accelerated stability testing as per ICH guidelines. Optimization results indicated that to a certain extent drug release was less effected by the orifice size, concentration of coating solution and coating weight. DSC showed the excipients used in the formulation did not alter physicochemical properties of the drug. The results confirmed that the factors responsible for drug release were osmotic agents (core and orifice size membrane.

  7. Charge independence and charge symmetry

    CERN Document Server

    Miller, G A; Miller, Gerald A; van Oers, Willem T H

    1994-01-01

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed.

  8. Charge independence and charge symmetry

    International Nuclear Information System (INIS)

    Charge independence and charge symmetry are approximate symmetries of nature, violated by the perturbing effects of the mass difference between up and down quarks and by electromagnetic interactions. The observations of the symmetry breaking effects in nuclear and particle physics and the implications of those effects are reviewed. (author). 145 refs., 3 tabs., 11 figs

  9. Electro-Optical Laser Technology. Curriculum Utilization. Final Report.

    Science.gov (United States)

    Nawn, John H.

    This report describes a program to prepare students for employment as laser technicians and laser operators and to ensure that they have the necessary skills required by the industry. The objectives are to prepare a curriculum and syllabus for an associate degree program in Electro-Optical Laser Technology. The 2-year Electro-Optical Laser program…

  10. 49 CFR 236.837 - Valve, electro-pneumatic.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Valve, electro-pneumatic. 236.837 Section 236.837 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Valve, electro-pneumatic. A valve electrically operated which, when operated, will permit or...

  11. Method for the electro-addressable functionalization of electrode arrays

    Energy Technology Data Exchange (ETDEWEB)

    Harper, Jason C.; Polsky, Ronen; Dirk, Shawn M.; Wheeler, David R.; Arango, Dulce C.; Brozik, Susan M.

    2015-12-15

    A method for preparing an electrochemical biosensor uses bias-assisted assembly of unreactive -onium molecules on an electrode array followed by post-assembly electro-addressable conversion of the unreactive group to a chemical or biological recognition group. Electro-addressable functionalization of electrode arrays enables the multi-target electrochemical sensing of biological and chemical analytes.

  12. Defence electro-optics: European perspective

    Science.gov (United States)

    Hartikainen, Jari

    2011-11-01

    In 2009 the United States invested in defence R&T 3,6 times and in defence research and development 6,8 times as much as all member states of the European Defence Agency (EDA) combined while the ratio in the total defence expenditure was 2,6 in the US' favour. The European lack of investments in defence research and development has a negative impact on the competitiveness of European defence industry and on the European non-dependence. In addition, the efficiency of investment is reduced due to duplication of work in different member states. The Lisbon Treaty tasks EDA to support defence technology research, and coordinate and plan joint research activities and the study of technical solutions meeting future operational needs. This paper gives an overview how EDA meets the challenge of improving the efficiency of European defence R&T investment with an emphasis on electro-optics and describes shortly the ways that governmental and industrial partners can participate in the EDA cooperation. Examples of joint R&T projects addressing electro-optics are presented.

  13. Electro-optics and lasers in Israel

    Science.gov (United States)

    Van Zwaren, Joesph

    1992-05-01

    With over 3,000 scientists, engineers, and technicians spread out in some 86 companies, and in 10 universities and research institutes, all within less than a 2 hour drive from one another, Israel has no doubt one of the largest concentrations of researchers and skilled manpower in electro-optics and lasers in the world. This report presents an up-to-date picture of the field in Israel, covering the industry, academia and education. The recent wave of Russian immigration is bringing thousands of scientists and tens of thousands of engineers and is expected to make an impact on the field of electro-optics and lasers. A million immigrants from Russia are expected to come between 1990 and 1995. There were 3,700 scientists and 2,800 engineers among the first 200,000 Soviet immigrants. As most of this qualified manpower can not be expected to be absorbed by the existing industry, the Israeli government is actively encouraging local and foreign investors and local and multinational companies to help develop new and expanded high-tech enterprises in Israel. The Ministry of Industry and Trade has embarked upon a broad ranged program for industrial growth and immigrant absorption with the goal of doubling technology-based exports in the next four years. The Ministry of Science and Technology has started a program supporting R&D projects at the different universities for immigrant scientists with the goal of capitalizing on the talents of the newcomers to strengthen academia.

  14. Electro-optic device with gap-coupled electrode

    Science.gov (United States)

    Deri, Robert J.; Rhodes, Mark A.; Bayramian, Andrew J.; Caird, John A.; Henesian, Mark A.; Ebbers, Christopher A.

    2013-08-20

    An electro-optic device includes an electro-optic crystal having a predetermined thickness, a first face and a second face. The electro-optic device also includes a first electrode substrate disposed opposing the first face. The first electrode substrate includes a first substrate material having a first thickness and a first electrode coating coupled to the first substrate material. The electro-optic device further includes a second electrode substrate disposed opposing the second face. The second electrode substrate includes a second substrate material having a second thickness and a second electrode coating coupled to the second substrate material. The electro-optic device additionally includes a voltage source electrically coupled to the first electrode coating and the second electrode coating.

  15. Charged Leptons

    CERN Document Server

    Albrecht, J; Babu, K; Bernstein, R H; Blum, T; Brown, D N; Casey, B C K; Cheng, C -h; Cirigliano, V; Cohen, A; Deshpande, A; Dukes, E C; Echenard, B; Gaponenko, A; Glenzinski, D; Gonzalez-Alonso, M; Grancagnolo, F; Grossman, Y; Harnik, R; Hitlin, D G; Kiburg, B; Knoepfe, K; Kumar, K; Lim, G; Lu, Z -T; McKeen, D; Miller, J P; Ramsey-Musolf, M; Ray, R; Roberts, B L; Rominsky, M; Semertzidis, Y; Stoeckinger, D; Talman, R; Van De Water, R; Winter, P

    2013-01-01

    This is the report of the Intensity Frontier Charged Lepton Working Group of the 2013 Community Summer Study "Snowmass on the Mississippi", summarizing the current status and future experimental opportunities in muon and tau lepton studies and their sensitivity to new physics. These include searches for charged lepton flavor violation, measurements of magnetic and electric dipole moments, and precision measurements of the decay spectrum and parity-violating asymmetries.

  16. Single-Step Electrophoretic Deposition of Non-noble Metal Catalyst Layer with Low Onset Voltage for Ethanol Electro-oxidation.

    Science.gov (United States)

    Ahmadi Daryakenari, Ahmad; Hosseini, Davood; Ho, Ya-Lun; Saito, Takumi; Apostoluk, Aleksandra; Müller, Christoph R; Delaunay, Jean-Jacques

    2016-06-29

    A single-step electrophoretic deposition (EPD) process is used to fabricate catalyst layers which consist of nickel oxide nanoparticles attached on the surface of nanographitic flakes. Magnesium ions present in the colloid charge positively the flake's surface as they attach on it and are also used to bind nanographitic flakes together. The fabricated catalyst layers showed a very low onset voltage (-0.2 V vs Ag/AgCl) in the electro-oxidation of ethanol. To clarify the occurring catalytic mechanism, we performed annealing treatment to produce samples having a different electrochemical behavior with a large onset voltage. Temperature dependence measurements of the layer conductivity pointed toward a charge transport mechanism based on hopping for the nonannealed layers, while the drift transport is observed in the annealed layers. The hopping charge transport is responsible for the appearance of the low onset voltage in ethanol electro-oxidation. PMID:27295080

  17. Chemo-electro-mechanical modeling of pH-sensitive hydrogels

    Science.gov (United States)

    Wallmersperger, Thomas; Keller, Karsten; Kröplin, Bernd; Günther, Margarita; Gerlach, Gerald

    2011-04-01

    Hydrogels are viscoelastic active materials. They consist of a polymer network with bound charges and a liquid phase with mobile anions and cations. In water based solutions these gels show large swelling capabilities under the influence of different possible stimulation types, such as chemical, electrical or thermal stimulation. In the present work a coupled chemo-electro-mechanical formulation for polyelectrolyte gels using the Finite Element Method (FEM) is applied. In addition to the three given fields, the dissociation reactions of the bound charges in the gel are considered. Thus, we are able to model and simulate pH-stimulation and to give the different ion concentrations, the electric potential and the mechanical displacement. Depending on the initial conditions and the dissociation ratio, different kinds of stimulation cycles can be simulated. Concluding, the developed model is applicable for chemical stimulation and can model both, hydrogel actuators and sensors.

  18. Sixteen-Day Bedrest Significantly Increases Plasma Colloid Osmotic Pressure

    Science.gov (United States)

    Hargens, Alan R.; Hsieh, S. T.; Murthy, G.; Ballard, R. E.; Convertino, V. A.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    Upon exposure to microgravity, astronauts lose up to 10% of their total plasma volume, which may contribute to orthostatic intolerance after space flight. Because plasma colloid osmotic pressure (COP) is a primary factor maintaining plasma volume, our objective was to measure time course changes in COP during microgravity simulated by 6 deg. head-down tilt (HDT). Seven healthy male subjects (30-55 years of age) were placed in HDT for 16 days. For the purpose of another study, three of the seven subjects were chosen to exercise on a cycle ergometer on day 16. Blood samples were drawn immediately before bedrest on day 14 of bedrest, 18-24 hours following exercise while all subjects were still in HDT and 1 hour following bedrest termination. Plasma COP was measured in all 20 microliter EDTA-treated samples using an osmometer fitted with a PM 30 membrane. Data were analyzed with paired and unpaired t-tests. Plasma COP on day 14 of bedrest (29.9 +/- 0.69 mmHg) was significantly higher (p less than 0.005) than the control, pre-bedrest value (23.1 +/- 0.76 mmHg). At one hour of upright recovery after HDT, plasma COP remained significantly elevated (exercise: 26.9 +/- 0.87 mmHg; no exercise: 26.3 +/- 0.85 mmHg). Additionally, exercise had no significant effect on plasma COP 18-24 hours following exercise (exercise: 27.8 +/- 1.09 mmHg; no exercise: 27.1 +/- 0.78 mmHg). Our results demonstrate that plasma COP increases significantly with microgravity simulated by HDT. However, preliminary results indicate exercise during HDT does not significantly affect plasma COP.

  19. Electro-membrane processes for flue gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, T. F.

    1997-12-31

    Various techniques for NO removal in Membrane Contactor were considered. However the NO absorption in a liquid adsorbent with chemical enhancement and its ease for regeneration, was selected as the most practicable choice. Various different compounds for chemical enhancement were studied and Fe(II)-chelate enhanced adsorbent was selected for further studies. The technical feasibility of Fe(II)-chelate enhanced adsorbent for obtaining greater than 80% NO removal have been successfully established. Even though the membrane area required for greater than 80% NO removal has been found to be about 500 m{sup 2}/MW{sub c} (compared to 50 - 150 m{sup 2}/MW{sub c}, for 95% SO{sub 2} removal, depending on the membrane characteristics), suitable Membrane Contactor design has been proposed for carrying out the process at an acceptable gas side pressure drop. The electro-membrane processes for the regeneration of adsorbents have been studied both theoretically and experimentally. The theoretical studies have concerned the study of basic functions of both the bipolar membranes and charge laden (anion/cation) membranes. Suitable experimental techniques have been devised for studying of these basic parameters (e.g. charge transport number, salt diffusion through membranes, current-voltage characteristics of bipolar membranes and electrical resistance of charge laden membranes). These parameters have further been utilized in the mechanistic model of combined membranes in an ED cell (electrodialysis). Based on these fundamental studies and analysis of process requirements, suitable configuration of ED cell has been developed and verified by experimental studies. The effect of both the stack design parameters (e.g. number of cells, membrane type and spacer design) and the operational parameters (e.g. temperature, electrolyte concentration, liquid velocity and current density) have been studied for optimization of energy consumption for regeneration of loaded adsorbents. As a result

  20. Wheat can acclimate to seawater by pretreatment with kinetin and spermine through osmotic adjustment and solutes allocation

    OpenAIRE

    Heshmat S. Aldesuquy; Baka, Zakaria A; Berdees M. Mickky

    2013-01-01

    A key issue in salt adaptation is the osmotic adjustment, therefore, during ear emergence the effect of exogenous application of kinetin and spermine on osmotic pressure (OP) and solutes allocation (total soluble sugars, total soluble nitrogen, proline, organic acids and inorganic ions (Na +, K +, Ca 2+, Mg 2+ and Cl -) were quantified in flag leaf of wheat plants irrigated by seawater at 25%. Seawater salinity induced significant increase in osmotic pressure. Furthermore, seawater stress ind...

  1. Micro electro mechanical system optical switching

    Science.gov (United States)

    Thorson, Kevin J; Stevens, Rick C; Kryzak, Charles J; Leininger, Brian S; Kornrumpf, William P; Forman, Glenn A; Iannotti, Joseph A; Spahn, Olga B; Cowan, William D; Dagel, Daryl J

    2013-12-17

    The present disclosure includes apparatus, system, and method embodiments that provide micro electo mechanical system optical switching and methods of manufacturing switches. For example, one optical switch embodiment includes at least one micro electro mechanical system type pivot mirror structure disposed along a path of an optical signal, the structure having a mirror and an actuator, and the mirror having a pivot axis along a first edge and having a second edge rotatable with respect to the pivot axis, the mirror being capable of and arranged to be actuated to pivot betweeen a position parallel to a plane of an optical signal and a position substantially normal to the plane of the optical signal.

  2. Iterative electro-optic matrix processor

    Science.gov (United States)

    Carlotto, M. J.

    An electro-optic vector matrix processor with electronic feedback is described. The iterative optical processor (IOP) is designed for the rapid solution of linear algebraic equations. The IOP and the iterative algorithm it realizes are analyzed and simulated. A version of the system was fabricated using advanced solid state light sources and detectors plus fiber optic technology, and its performance is evaluated. An extension of the system using wavelength multiplexing is developed and the basic system concepts demonstrated. Its use in the restoration of degraded images or signals (deconvolution) and the computation of matrix eigenvectors and eigenvalues and matrix inversion are demonstrated. The two major case studies pursued are: adaptive phased array radar processing and optimal control. In the former case, the system is used to compute the adaptive antenna weights for a radar system. In the latter case, the IOP solves the linear quadratic regular and algebraic Ricatti equations of modern control theory.

  3. Concrete decontamination by electro-hydraulic scabbling

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, V.; Gannon, R. [Textron Defense System, Everett, MA (United States)

    1995-10-01

    Textron Defense Systems (TDS) is developing an electro-hydraulic device that has the potential for faster, safer, and less expensive scabbling of contaminated concrete surfaces. In the device, shock waves and cavitating bubbles are produced in water by the electric pulses, and the direct and reflected shock waves impinging on the concrete surface result in the crushing and cracking of the concrete. Pulse energy, frequency, and traverse speed control the depth of the scabbling action. Performance thus far has demonstrated the capability of a prototype unit to process a swath 24 inches wide, up to 3/4 inch deep at a linear velocity of up to 6 feet per hour, i.e., at a scabbling rate of 12 sq. ft. per hour.

  4. MET Standards for Electro-Technical Officers

    Directory of Open Access Journals (Sweden)

    Janusz Mindykowski

    2014-12-01

    Full Text Available The paper deals with one of the most important changes in the STCW 1978 as amended in 2010 Convention, from the point of view of the watchkeeping officers responsible for control, maintenance, diagnostic and repair of electrical and electronic installations on board of ships. Some reasons, why the MET Standards for Electro-Technical had to be developed and implemented are shortly analyzed and described. A legislative way towards and a short description of the minimum standards competence for ETO are presented. Next, new tools supporting ETO’s standards implementation are appointed. Finally, the future works as well as the concluding remarks concerning discussed issue are formulated and commented on.

  5. Mathematical methods in electro-magneto-elasticity

    CERN Document Server

    Bardzokas, DI; Filshtinsky, LA

    2007-01-01

    The mechanics of Coupled Fields is a discipline at the edge of modern research connecting Continuum Mechanics with Solid State Physics. It integrates the Mechanics of Continuous Media, Heat Conductivity and the theory of Electromagnetism that are usually studied separately. For an accurate description of the influence of static and dynamic loadings, high temperatures and strong electromagnetic fields in elastic media and constructive installations, a new approach is required; an approach that has the potential to establish a synergism between the above mentioned fields. Throughout the book a vast number of problems are considered: two-dimensional problems of electro-magneto-elasticity as well as static and dynamical problems for piecewise homogenous compound piezoelectric plates weakened by cracks and openings. The boundary conditions, the constructive equations and the mathematical methods for their solution are thoroughly presented, so that the reader can get a clear quantitative and qualitative understandi...

  6. Electro neutrons around a 12 MV Linac

    International Nuclear Information System (INIS)

    Neutron contamination around Linacs for radiotherapy is a source of undesirable doses for the patient. The main source of these neutrons is the photonuclear reactions occurring in the Linac head and the patient body. Electrons also produce neutrons through (e, en) reactions. This reaction is known as electro disintegration and is carried out by the electron scattering that produce a virtual photon that is absorbed by the scattering nucleus producing the reaction e + A → (A-1) + n + e'. In this work the electron-neutron spectrum to 100 cm from the isocenter of a 12 MV Linac has been measured using a passive Bonner spheres spectrometer in a novel procedure named Planetary mode. (Author)

  7. Electro neutrons around a 12 MV Linac

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico); Perez L, L. H., E-mail: fermineutron@yahoo.com [Instituto Zacatecano del Tumor, A. C., Lago de la Encantada No. 294, Fracc. Lomas del Lago, Zacatecas (Mexico)

    2012-10-15

    Neutron contamination around Linacs for radiotherapy is a source of undesirable doses for the patient. The main source of these neutrons is the photonuclear reactions occurring in the Linac head and the patient body. Electrons also produce neutrons through (e, en) reactions. This reaction is known as electro disintegration and is carried out by the electron scattering that produce a virtual photon that is absorbed by the scattering nucleus producing the reaction e + A {yields} (A-1) + n + e'. In this work the electron-neutron spectrum to 100 cm from the isocenter of a 12 MV Linac has been measured using a passive Bonner spheres spectrometer in a novel procedure named Planetary mode. (Author)

  8. Electro-optical tunable birefringent filter

    Energy Technology Data Exchange (ETDEWEB)

    Levinton, Fred M. (Princeton, NJ)

    2012-01-31

    An electrically tunable Lyot type filter is a Lyot that include one or more filter elements. Each filter element may have a planar, solid crystal comprised of a material that exhibits birefringence and is electro-optically active. Transparent electrodes may be coated on each face of the crystal. An input linear light polarizer may be located on one side of the crystal and oriented at 45 degrees to the optical axis of the birefringent crystal. An output linear light polarizer may be located on the other side of the crystal and oriented at -45 degrees with respect to the optical axis of the birefringent crystal. When an electric voltage is applied between the electrodes, the retardation of the crystal changes and so does the spectral transmission of the optical filter.

  9. Conception of Electro-Stimulation System

    Directory of Open Access Journals (Sweden)

    Adil Salbi

    2014-10-01

    Full Text Available The aim of this work is to suggest a reliable solution of electro-stimulation making it possible to restore defective functions of the nervous systems among certain patients. This solution consists in creating a signal similar to that arriving of the central nervous system. Thus, work presented aims to design an electronic circuit of stimulation allowing the contraction of the muscle to restore its function by a biphasic train of electric impulse. This stimulator system is composed of a clock, an inverter and a logical sequencer which shifts the clock signal. The stage of power makes it possible to adapt the signals newcomers on a transformer booster coupled to a stage of order to regulate the amplitude of the impulse.

  10. Photoinduced electro-optics measurements of biosilica transformation to cristobalite

    International Nuclear Information System (INIS)

    In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica. - Graphical abstract: The phase transformation of biosilica from marine sponges to Cristobalite under thermal treatment was investigated using photoinduced electro optics measurements. The figure shows the changes of the electro-optic coefficient of cristobalite and biosilica. - Highlights: • We examine phase transformation of biosilica. • We report transition from amorphous biosilica to crystalline Cristobalite. • Biosilica transformation to Cristobalite at temperature of 850 °C. • Biosilica transformation is studied with photoinduced measurements. • We examine changes in the photoinduced linear electro optics properties

  11. Photoinduced electro-optics measurements of biosilica transformation to cristobalite

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Ido [Department of Chemistry and the Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900 (Israel); Aluma, Yaniv; Ilan, Micha [Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Kityk, Iwan [Institute of Electronic Systems, Faculty of Electrical Engineering, Czestochowa University, Czestochowa 42-201 (Poland); Mastai, Yitzhak, E-mail: Yitzhak.Mastai@biu.ac.il [Department of Chemistry and the Institute of Nanotechnology, Bar-Ilan University, Ramat-Gan 52900 (Israel)

    2015-03-15

    In this paper we studied the photoinduced electro optics effects in the thermal transformation process of biosilica to cristobalite, at a relatively low temperature and ambient pressure. This process was characterized by a variety of standards techniques with emphasis on linear electro optic effect measurements. Overall we demonstrated that photoinduced electro optics measurements are very sensitive to the transformation from amorphous structure of silica in the natural sponge samples to laminar string morphology of cristobalite. With this technique we could probe the change in the samples chirality from achiral bio silica to chiral cristobalite structure. Furthermore it is shown that natural biosilica have photoinduced linear electro optics respond indicating the chiral natural of biosilica. - Graphical abstract: The phase transformation of biosilica from marine sponges to Cristobalite under thermal treatment was investigated using photoinduced electro optics measurements. The figure shows the changes of the electro-optic coefficient of cristobalite and biosilica. - Highlights: • We examine phase transformation of biosilica. • We report transition from amorphous biosilica to crystalline Cristobalite. • Biosilica transformation to Cristobalite at temperature of 850 °C. • Biosilica transformation is studied with photoinduced measurements. • We examine changes in the photoinduced linear electro optics properties.

  12. Electro-optic high voltage sensor

    Science.gov (United States)

    Davidson, James R.; Seifert, Gary D.

    2002-01-01

    A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal having at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

  13. Interaction of prechilling, temperature, osmotic stress, and light in Picea abies seed germination

    International Nuclear Information System (INIS)

    A multi-factor experimental approach and proportional odds model was used to study interactions between five environmental factors significant to Norway spruce seed germination: prechilling (at +4.5 °C), suboptimal temperatures (+12 and +16 °C), osmotically induced water stress (–0.3 Mpa and 0 Mpa), prolonged white light, and short-period far-red light. Temperature and osmotic stress interacted with one another in the germination of seeds: the effect of osmotic stress being stronger at +16 °C than at +12 °C. In natural conditions, this interaction may prevent germination early in the summer when soil dries and temperature increases. Prolonged white light prevented germination at low temperature and low osmotic potential. Inhibitory effect was less at higher temperatures and higher osmotic potential, as well as after prechilling. Short-period far-red light did not prevent germination of unchilled seeds in darkness. Prechilling tended to make seeds sensitive to short pulses of far-red light, an effect which depended on temperature: at +12 °C the effect on germination was promotive, but at +16 °C, inhibitory and partly reversible by white light. It seems that Norway spruce seeds may have adapted to germinate in canopy shade light rich in far-red. The seeds may also have evolved mechanisms to inhibit germination in prolonged light

  14. Early selection of kabuli chickpea genotypes (Cicer arietinum L. tolerant to osmotic water stress

    Directory of Open Access Journals (Sweden)

    Kamel Ben Mbarek

    2013-05-01

    Full Text Available Eight " kabuli " chickpea genotypes Beja1, Amdoun1, Nayer, Kasseb, Bochra, FLP96-114C, FLP88-42C and Chetoui were germinated, in two in vitro culture media, particularly, agar and filter paper Watman n°2 and under tree osmotic water pressures (OWP: -0,33; -4 and -8 bars induced by PEG8000. On filter paper, germination appeared more accelerated with a higher rate compared to the agar media. Osmotic water stress has negatively affected the seeds germination and the seedlings vegetative development parameters. Osmotic water pressure - 8 bars completely inhibited seeds germination on filter paper media. On the other hand, on agar media, it caused a feeble germination rate and a stunting of the seedlings. A broad genotypic variability of the chickpea cultivars was revealed toward the osmotic water stress. Tolerance index to osmotic water stress revealed three groups of cultivars: (1 Nayer and Kasseb are tolerant, (2 Bochra, FLIP88-42C and Chetoui are fairly tolerant and (3 Amdoun1, Beja1 and FLIP96-114C are sensitive to this abiotic stress.

  15. Early osmotic adjustment responses in drought-resistant and drought-sensitive oilseed rape

    Institute of Scientific and Technical Information of China (English)

    Sarah Hatzig; L Irina Zaharia; Suzanne Abrams; Marie Hohmann; Laurie Legoahec; Alain Bouchereau; Nathalie Nesi; Rod J.Snowdon

    2014-01-01

    The impact of osmotic stress on growth, physiolo-gy, and metabolism of winter oilseed rape (Brassica napus L.) was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genetical y unrelated drought-tolerant genotypes and two unrelated drought-sensitive genotypes. Seedlings were grown in vitro under control ed conditions and osmotic stress was simulated by applying a gradual treatment with polyethylene glycol (PEG 6000), fol owed by hypo-osmotic treatment of variants used for metabolite determination. The results provide a basis for the identification of reliable selection criteria for drought resistance in oilseed rape. The in vitro cultivation system established during this study enabled effective discrimination of early osmotic stress responses between drought-resistant and-susceptible oilseed rape genotypes that also show large differences in relative seed yield under drought conditions in the field. Clear physiological and metabolic differences were observed between the drought-resistant and drought-sensitive genotypes, suggesting that osmotic adjustment is a key component of drought response in oilseed rape. Unexpected-ly, however, the drought-resistant genotypes did not show typical hormonal adjustment and osmolyte accumulation, suggesting that they possess alternative physiological mech-anisms enabling avoidance of stress symptoms.

  16. Physicochemical characteristics of guava “Paluma” submitted to osmotic dehydration

    Directory of Open Access Journals (Sweden)

    Roselene Ferreira Oliveira

    2014-09-01

    Full Text Available The aim of this work was to evaluate the conservation post process osmotic of guava stored temperature at 5oC. Guava (Psidium guajava L., red variety “Paluma” minimally processed by mild osmotic dehydration, were packaged in polyethylene terephthalate (PET and stored temperature at 5ºC. Non-treated guava, packed in PET trays, was used as control. The treatment used was osmotic dehydration in sucrose syrup at 60ºBrix and physicochemical determinations were pH, total soluble solids (TSS, total titratable acidity (TTA, reducing sugars (RS, total sugars (TS and parameters related to colour read (a*, chroma (c*, yellow (b*, luminosity (L* of the fresh and osmotically dehydrated guava slices. The dehydrated fruits lost about 34.45% of water, concentrating contents of soluble solids, total and reducing sugars, when compared to control samples. The pH value remained around 3.76 for the OD fruits and 3.87 for the fresh fruits. The colour of the dehydrated fruits was more intense than the control samples’. The guava slices osmotic dehydration had 21 days of shelf life, showed physicochemical characteristics significantly superior to the control samples’, having a stable and high quality product as a result.

  17. Changes of DHN1 expression and subcellular distribution in A. delicisoa cells under osmotic stress

    Institute of Scientific and Technical Information of China (English)

    QIU; Quansheng; (邱全胜); WANG; Zezhou(王泽宙); CAI; Qigui(蔡起贵); JIANG; Rongxi(姜荣锡)

    2002-01-01

    The changes of DHN1 expression and subcellular distribution in A. delicisoa cells under osmotic stress were studied by using GFP as a reporter molecule. Through creating the Xba I and BamH I restriction sites at the ends of dhn1 by PCR, the expression vector for the fusion protein DHN1-mGFP4 was constructed by cloning dhn1 into plasmid pBIN-35SmGFP4. Then the DHN1-mGFP4 expression vector was transformed into A. delicisoa suspension cells by microprojectile bombardment method. Bright green fluorescence of GFP which shows the high-level expression of DHN1-mGFP4 was visualized after culture for 10 h. However, the green fluorescence was only located within the nucleus. By increasing the culture medium osmotic potential, the green fluorescence was visualized in the cytoplasm (mainly around the plasma membranes). The generation of GFP fluorescence in the cytoplasm was also promoted by increasing the medium osmotic potential. Moreover, GFP green fluorescence was abolished by protein synthesis inhibitor dicyclohexylcarbodiimid, indicating that the cytoplasmic DHN1 was newly synthesized under osmotic stress. Furthermore, ABA promoted the presence of green fluorescence in the cytoplasm, and the GFP fluorescence was visualized within a shorter time under a higher osmotic potential.

  18. Osmotic stress at the barley root affects expression of circadian clock genes in the shoot.

    Science.gov (United States)

    Habte, Ermias; Müller, Lukas M; Shtaya, Munqez; Davis, Seth J; von Korff, Maria

    2014-06-01

    The circadian clock is an important timing system that controls physiological responses to abiotic stresses in plants. However, there is little information on the effects of the clock on stress adaptation in important crops, like barley. In addition, we do not know how osmotic stress perceived at the roots affect the shoot circadian clock. Barley genotypes, carrying natural variation at the photoperiod response and clock genes Ppd-H1 and HvELF3, were grown under control and osmotic stress conditions to record changes in the diurnal expression of clock and stress-response genes and in physiological traits. Variation at HvELF3 affected the expression phase and shape of clock and stress-response genes, while variation at Ppd-H1 only affected the expression levels of stress genes. Osmotic stress up-regulated expression of clock and stress-response genes and advanced their expression peaks. Clock genes controlled the expression of stress-response genes, but had minor effects on gas exchange and leaf transpiration. This study demonstrated that osmotic stress at the barley root altered clock gene expression in the shoot and acted as a spatial input signal into the clock. Unlike in Arabidopsis, barley primary assimilation was less controlled by the clock and more responsive to environmental perturbations, such as osmotic stress. PMID:24895755

  19. Osmotic coefficients and apparent molar volumes of 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid in alcohols

    International Nuclear Information System (INIS)

    Highlights: • Physical and osmotic properties of [HMim][TfO] in alcohols are reported. • Apparent molar properties and osmotic coefficients were obtained. • Apparent molar volumes were fitted using a Redlich–Meyer type equation. • The osmotic coefficients were modeled with the Extended Pitzer and the MNRTL models. -- Abstract: In this work, density for the binary mixtures of 1-hexyl-3-methylimidazolium trifluoromethanesulfonate in alcohols (1-propanol, or 2-propanol, or 1-butanol, or 2-butanol, or 1-pentanol) was measured at T = 323.15 K and atmospheric pressure. From this property, the corresponding apparent molar volumes were calculated and fitted to a Redlich–Meyer type equation. For these mixtures, the osmotic and activity coefficients, and vapor pressures of these binary systems were also determined at the same temperature using the vapor pressure osmometry technique. The experimental osmotic coefficients were modeled by the Extended Pitzer model of Archer. The parameters obtained in this correlation were used to calculate the mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures

  20. Osmotic and apparent molar properties of binary mixtures alcohol + 1-butyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid

    International Nuclear Information System (INIS)

    Highlights: ► Osmotic and physical properties of binary mixtures {alcohol + [BMim][TfO]} were measured. ► From experimental data, apparent molar properties and osmotic coefficients were calculated. ► The apparent properties were fitted using a Redlich–Meyer type equation. ► The osmotic coefficients were correlated using the Extended Pitzer model. -- Abstract: In this work, physical properties (densities and speeds of sound) for the binary systems {1-propanol, or 2-propanol, or 1-butanol, or 2-butanol, or 1-pentanol + 1-butyl-3-methylimidazolium trifluoromethanesulfonate} were experimentally measured from T = (293.15 to 323.15) K and at atmospheric pressure. These data were used to calculate the apparent molar volume and apparent molar isentropic compression which were fitted to a Redlich–Meyer type equation. This fit was used to obtain the corresponding apparent molar properties at infinite dilution. On the other hand, the osmotic and activity coefficients and vapor pressures of these binary mixtures were also determined at T = 323.15 K using the vapor pressure osmometry technique. The Extended Pitzer model of Archer was employed to correlate the experimental osmotic coefficients. From the parameters obtained in the correlation, the mean molal activity coefficients and the excess Gibbs free energy for the studied mixtures were calculated

  1. Development and Optimization of Elementary osmotic pump tablet of Nicardipine Hydrochloride using central composite experimental Design

    Directory of Open Access Journals (Sweden)

    Mehta Teja

    2013-09-01

    Full Text Available Elementary Osmotic Pumps (EOP consists of osmotic core (coated with a semipermeable membrane (SPM and a small orifice is created in the membrane. The objective of the present study was to develop an optimized EOP tablets containing inclusion complex of Nicardipine Hydrochloride (NH using central composite design. Amount of osmotic agent (X1 and size of delivery orifice (X2 were selected as independent variables. Formulations were prepared by direct compression method and evaluated for % Cumulative Drug Release (% CDR at 540min. as dependent variables. Amount of osmotic agent and size of delivery orifice had a significant effect on % CDR. The results of multiple linear regression analysis revealed that EOP tablets should be prepared using an optimum concentration of osmotic agent and size of delivery orifice to achieve a zero order drug release. Contour plots as well as response surface plots were constructed to show the effects of X1 and X2 on % CDR. A model was validated for accurate prediction of % CDR by performing checkpoint analysis. The computer optimization process, contour plots and response surface plots predicted at the concentration of independent variables X1 and X2 (50mg and 0.8mm respectively, for maximized response. The drug release from the developed formulation was found independent of pH and agitational intensity. The above optimized batch was also evaluated by different pharmacokinetic models. Stability study of optimized batch was conducted at accelerated conditions for six month and it was found to be stable.

  2. Osmotic damage as a predictor of motility loss during convective desiccation of bovine sperm.

    Science.gov (United States)

    Sitaula, Ranjan; Jimenez, Jorge; Bhowmick, Sankha

    2013-12-01

    Current state-of-the art technologies are lagging in the application of desiccation storage to mammalian cells using nonreducing sugars. For bovine sperm, motility is irreversibly lost before reaching a sufficiently low moisture content necessary for preservation. It is hypothesized that much of the damage during drying is related to the osmotic stress encountered due to increased osmolarity of the extracellular environment. To test this hypothesis, we subjected sperm to liquid hyperosmotic environments for varying time-periods and measured their motility. We then extracted parameters for two models for motility loss based on these experiments: a first-order rate injury model (Fast or Slow) and a multi-modal (MM) injury model. The MM injury model incorporated an additional function accounting for damage induced by a time-independent osmotic change. Based on these models, we predicted sperm motility loss measured from natural and forced convective desiccation experiments. The MM injury model was able to closely bracket motility loss for desiccation as an osmotic change event with time-independent and time-dependent components. While the mechanistic basis of osmotic damage requires further exploration, the model can serve as a bracketing tool for predicting motility loss during desiccation based on excipients designed to minimize osmotic damage. PMID:24835367

  3. Flow cytometric determination of osmotic behaviour of animal erythrocytes toward their engineering for drug delivery

    Directory of Open Access Journals (Sweden)

    Kostić Ivana T.

    2015-01-01

    Full Text Available Despite the fact that the methods based on the osmotic properties of the cells are the most widely used for loading of drugs in human and animal erythrocytes, data related to the osmotic properties of erythrocytes derived from animal blood are scarce. This work was performed with an aim to investigate the possibility of use the flow cytometry as a tool for determination the osmotic behaviour of porcine and bovine erythrocytes, and thus facilitate the engineering of erythrocytes from animal blood to be drug carriers. The method of flow cytometry successfully provided the information about bovine and porcine erythrocyte osmotic fragility, and made the initial steps in assessment of erythrocyte shape in a large number of erythrocytes. Although this method is not able to confirm the swelling of pig erythrocytes, it indicated to the differences in pig erythrocytes that had basic hematological parameters inside and outside the reference values. In order to apply/use the porcine and bovine erythrocytes as drug carriers, the method of flow cytometry, confirming the presence of osmotically different fractions of red blood cells, indicated that various amounts of the encapsulated drug in porcine and bovine erythrocytes can be expected.

  4. Electro-Optical System Design for Information Processing

    OpenAIRE

    Wyatt, Clair L.

    1991-01-01

    This practical text/reference provides a clear,systems-oriented approach to electro-optical system design. Covering electro-optical systems that are used for information processing,the book focuses on those systems that convey information via an electro-optical beam as in remote sensing,guidance and tracking,and fiber optic and laser communication systems. With 30% more pages,this book is a greatly expanded and revised version of the author's Radiometric System Design. Part I prepares the rea...

  5. Permeability of Electro spun Super hydrophobic Nano fiber Mats

    International Nuclear Information System (INIS)

    This paper discusses the fabrication and characterization of electro spun nano fiber mats made up of poly(4-methyl-1-pentene) polymer. The polymer was electro spun in different weight concentrations. The mats were characterized by their basis weight, fiber diameter distribution, contact angles, contact angle hysteresis, and air permeability. All of the electro spun nonwoven fiber mats had water contact angles greater than 150 degrees making them super hydrophobic. The permeabilities of the mats were empirically fitted to the mat basis weight by a linear relation. The experimentally measured air permeabilities were significantly larger than the permeabilities predicted by the Kuwabara model for fibrous media.

  6. Electro-optic properties of hybrid solgel doped with a nonlinear chromophore with large hyperpolarizability.

    Science.gov (United States)

    Zhang, Hong Xi; Lu, Dong; Peyghambarian, Nasser; Fallahi, Mahmoud; Luo, Jing Dong; Chen, Bao Quan; Jen, Alex K Y

    2005-01-15

    We report the electro-optic properties of hybrid silica solgel doped with a nonlinear chromophore with large hyperpolarizability. Electro-optic coefficients of higher than 30 pm/V have been obtained. Moreover, the electro-optic coefficients have good temporal stability and show promise for the development of high-speed electro-optic devices. PMID:15675685

  7. Analysis of batch-related influences on injection molding processes viewed in the context of electro plating quality demands

    Science.gov (United States)

    Siepmann, Jens P.; Wortberg, Johannes; Heinzler, Felix A.

    2016-03-01

    The injection molding process is mandatorily influenced by the viscosity of the material. By varying the material batch the viscosity of the polymer changes. For the process and part quality the initial conditions of the material in addition to the processing parameters define the process and product quality. A high percentage of technical polymers processed in injection molding is refined in a follow-up production step, for example electro plating. Processing optimized for electro plating often requires avoiding high shear stresses by using low injection speed and pressure conditions. Therefore differences in the material charges' viscosity occur especially in the quality related low shear rate area. These differences and quality related influences can be investigated by high detail rheological analysis and process simulation based on adapted material describing models. Differences in viscosity between batches can be detected by measurements with high-pressure-capillary-rheometers or oscillatory rheometers for low shear rates. A combination of both measurement techniques is possible by the Cox-Merz-Relation. The detected differences in the rheological behavior of both charges are summarized in two material behavior describing model approaches and added to the simulation. In this paper the results of processing-simulations with standard filling parameters are presented with two ABS charges. Part quality defining quantities such as temperature, pressure and shear stress are investigated and the influence of charge variations is pointed out with respect to electro plating quality demands. Furthermore, the results of simulations with a new quality related process control are presented and compared to the standard processing.

  8. Temperature and pressure dependent osmotic pressure in liquid sodium-cesium alloys

    International Nuclear Information System (INIS)

    The evaluation of the osmotic pressure in terms of the concentration fluctuations of mixtures and the equations of state of the pure liquids is considered. The temperature and pressure dependent experimentally measured concentration-concentration correlations in the long wavelength limit of liquid sodium-cesium alloys are used to demonstrate the appreciable dependence of the temperature and pressure on the osmotic pressure as a function of concentration. Introducing interchange energies as functions of temperature and pressure, our analysis is consistent with the Flory model. Thus, a formalism for evaluating the state dependent osmotic pressure is developed and our numerical work is considered to be an extension of the calculations of Rashid and March in the sense that a temperature and pressure dependent interchange energy parameter that more closely parameterizes the state dependent concentration fluctuations in the liquid alloys, is used. (author)

  9. Development and Evaluation of Extended Release Formulation of Tramadol Hydrochloride Based on Osmotic Technology

    Directory of Open Access Journals (Sweden)

    Patel JB

    2013-05-01

    Full Text Available Extended release formulation of Tramadol Hydrochloride based on osmotic technology was developedand evaluated. Target release profile was selected and different variables were optimized to achieve it.Formulation variables such as osmotic agent, plasticizer and coating thickness of semi-permeablemembrane were found to markedly affect drug release. Tramadol hydrochloride release was directlyproportional to the level of osmogent and plasticizer but inversely proportional to the level of coatingthickness of semi-permeable membrane. Drug release from developed formulation was independent ofpH and agitation intensity but dependent on osmotic pressure of release media. The optimizedformulation was compared with marketed product CONTRAMAL SR and accelerated stability studywas also carried out for 6 months.

  10. Recommendation to use iso-osmotic contrast medium in interventional treatment

    International Nuclear Information System (INIS)

    With the rapid development of imaging diagnostic and interventional therapeutic techniques, the contrast medium (CM) has been used more and more common in clinical practice, and meanwhile more and more attention has been paid to the CM-related adverse events. Contrast induced nephropathy (CN) is the most common CM-related adverse event, and CM-related neurotoxicity has already attracted the physicians' attention. The osmotic pressure of the iso-osmotic contrast medium (IOCM) is quite the same as that of the plasma, and therefore its safety is higher than that of low-osmotic contrast medium (LOCM), the patient's tolerance to IOCM is better than that to LOCM. For this reason, the use of IOCM should be strongly recommended in interventional procedures, which is of great significance to the reduction of the occurrence of CM-related adverse events. (authors)

  11. ′Wine Glass′ sign in recurrent postpartum hypernatremic osmotic cerebral demyelination

    Directory of Open Access Journals (Sweden)

    Aralikatte O Saroja

    2013-01-01

    Full Text Available Osmotic demyelination syndrome resulting from postpartum hypernatremia is a recently described entity wherein young women present with hypernatremic encephalopathy and white matter hyperintensities along with quadriparesis from rhabdomyolysis. It is an acute monophasic condition with acute hypernatremia occurring during puerperium with good recovery in majority of the patients with treatment. To the best of our knowledge, recurrent postpartum hypernatremia with encephalopathy, osmotic demyelination, and rhabdomyolysis has not been described. We present a young lady who had two episodes of reversible postpartum hypernatremic encephalopathy with rhabdomyolysis. Cerebral magnetic resonance imaging (MRI before treatment revealed osmotic demyelination on both occasions. During first admission MRI revealed hyperintensities in internal capsule and corpus callosum, and at second admission revealed more extensive white matter hyperintensity, which simulated the ′wine glass′ appearance.

  12. Impact of oxidative and osmotic stresses on Candida albicans biofilm formation.

    Science.gov (United States)

    Pemmaraju, Suma C; Padmapriya, Kumar; Pruthi, Parul A; Prasad, R; Pruthi, Vikas

    2016-09-01

    Candida albicans possesses an ability to grow under different host-driven stress conditions by developing robust protective mechanisms. In this investigation the focus was on the impact of osmotic (2M NaCl) and oxidative (5 mM H2O2) stress conditions during C. albicans biofilm formation. Oxidative stress enhanced extracellular DNA secretion into the biofilm matrix, increased the chitin level, and reduced virulence factors, namely phospholipase and proteinase activity, while osmotic stress mainly increased extracellular proteinase and decreased phospholipase activity. Fourier transform infrared and nuclear magnetic resonance spectroscopy analysis of mannan isolated from the C. albicans biofilm cell wall revealed a decrease in mannan content and reduced β-linked mannose moieties under stress conditions. The results demonstrate that C. albicans adapts to oxidative and osmotic stress conditions by inducing biofilm formation with a rich exopolymeric matrix, modulating virulence factors as well as the cell wall composition for its survival in different host niches. PMID:27472386

  13. OSMOTIC DEHYDRATION KINETICS OF GUAVAS IN MALTOSE SOLUTIONS WITH CALCIUM SALT*

    Directory of Open Access Journals (Sweden)

    S. DI S. MASTRANTONIO

    2009-03-01

    Full Text Available

    The osmotic dehydration kinetics of guavas in maltose solutions at 40 and 60ºBrix, with addition of 0, 0.6 and 1.2% of calcium lactate was studied in this paper and the final product quality was evaluated. The experiments were carried out up to 60 hours and samples were taken for analysis at different times to evaluate guavas weight reduction, water loss and sugar gain and to characterize the product according to its texture and color. After 24 hours of process the mass transfer of water and sugar between the osmotic solution and the fruit was negligible, showing that process equilibrium was reached. The increase of sugar concentration in the osmotic solution showed strong influence on the dehydration process, increasing the water loss and reducing sugar gain. The presence of calcium ions in the osmotic solution also influenced the kinetics of mass transfer and showed a strong influence on fruit texture. Higher values of stress and strain at failure were obtained when calcium lactate was employed. The effect of the different osmotic treatments on the color parameters was also investigated and significant changes were observed in the values of chroma C* and hue H* due to sugar concentration and calcium addition.

    KEYWORDS: Osmotic dehydration; kinetics; guava; maltose; calcium lactate.

  14. Electro-Optic Imaging Fourier Transform Spectral Polarimeter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Boulder Nonlinear Systems, Inc. (BNS) proposes to develop an Electro-Optic Imaging Fourier Transform Spectral Polarimeter (E-O IFTSP). The polarimetric system is...

  15. STUDY OF SALT WHEY TREATMENT WITH ELECTRO DIALYSIS

    Directory of Open Access Journals (Sweden)

    Permyakov A. V.

    2014-10-01

    Full Text Available The results of the effect of the electro dialysis treatment on the composition and properties of salt whey are presented. The main regularities of the demineralization process of salt whey and its efficiency are determined

  16. Use of Different Kinds of Solutes Alternative to Sucrose in Osmotic Dehydration of Yacon

    Directory of Open Access Journals (Sweden)

    Bethania Brochier

    2015-02-01

    Full Text Available The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble solids respectively. Maltodextrin did not promote dehydration.

  17. Use of Different Kinds of Solutes Alternative to Sucrose in Osmotic Dehydration of Yacon

    OpenAIRE

    Bethania Brochier; Ligia Damasceno Ferreira Marczak; Caciano Pelayo Zapata Noreña

    2015-01-01

    The present work aimed to evaluate glycerol, maltodextrin, polydextrose and sorbitol for the osmotic dehydration of yacon for diabetics, keeping its properties as prebiotic. Osmotic dehydration was carried out using a yacon to 33% concentrated syrup weight ratio of 1:12, with magnetic stirring at 23ºC and atmospheric pressure. The best results were achieved for glycerol and sorbitol with 80 ± 4% and 81± 1% of water removal and increase of 3.73 ± 0.11 and 4.30 ± 0.16 times in total soluble sol...

  18. Mathematical modelling of the osmotic dehydration of cherry tomato (Lycopersicon esculentum var. cerasiforme)

    OpenAIRE

    Patricia Moreira AZOUBEL; Murr Fernanda E. Xidieh

    2000-01-01

    Osmotic dehydration of cherry tomato as influenced by osmotic agent (sodium chloride and a mixed sodium chloride and sucrose solutions) and solution concentration (10 and 25% w/w) at room temperature (25°C) was studied. Kinetics of water loss and solids uptake were determined by a two parameter model, based on Fick's second law and applied to spherical geometry. The water apparent diffusivity coefficients obtained ranged from 2.17x10-10 to 11.69x10-10 m²/s.

  19. Influence on concentration of sugar on mass transfer of pineapple slices during osmotic dehydration

    OpenAIRE

    Khanom, S.A.A.; Rahman, M.M.; Uddin, M.B.

    2014-01-01

    Osmotic drying is a partial dehydration process to give the product a quality improvement over the conventional drying process. The experiment was conducted for studying water loss(WL), sugar gain(SG), weight reduction(WR) and total solid(TS) during osmotic dehydration of pineapple slices (10 mm thick) in different concentration of sugar (40%, 50% and 60%) up to 6 hours at room temperature. It was found that increasing the concentration of the sugar solution used resulted in increased rates o...

  20. A new equation of state of a flexible-chain polyelectrolyte solution: Phase equilibria and osmotic pressure in the salt-free case.

    Science.gov (United States)

    Budkov, Yu A; Kolesnikov, A L; Georgi, N; Nogovitsyn, E A; Kiselev, M G

    2015-05-01

    We develop a first-principle equation of state of salt-free polyelectrolyte solution in the limit of infinitely long flexible polymer chains in the framework of a field-theoretical formalism beyond the linear Debye-Hueckel theory and predict a liquid-liquid phase separation induced by a strong correlation attraction. As a reference system, we choose a set of two subsystems-charged macromolecules immersed in a structureless oppositely charged background created by counterions (polymer one component plasma) and counterions immersed in oppositely charged background created by polymer chains (hard-core one component plasma). We calculate the excess free energy of polymer one component plasma in the framework of modified random phase approximation, whereas a contribution of charge densities' fluctuations of neutralizing backgrounds we evaluate at the level of Gaussian approximation. We show that our theory is in a very good agreement with the results of Monte Carlo and MD simulations for critical parameters of liquid-liquid phase separation and osmotic pressure in a wide range of monomer concentration above the critical point, respectively. PMID:25956114

  1. A new equation of state of a flexible-chain polyelectrolyte solution: Phase equilibria and osmotic pressure in the salt-free case

    Science.gov (United States)

    Budkov, Yu. A.; Kolesnikov, A. L.; Georgi, N.; Nogovitsyn, E. A.; Kiselev, M. G.

    2015-05-01

    We develop a first-principle equation of state of salt-free polyelectrolyte solution in the limit of infinitely long flexible polymer chains in the framework of a field-theoretical formalism beyond the linear Debye-Hueckel theory and predict a liquid-liquid phase separation induced by a strong correlation attraction. As a reference system, we choose a set of two subsystems—charged macromolecules immersed in a structureless oppositely charged background created by counterions (polymer one component plasma) and counterions immersed in oppositely charged background created by polymer chains (hard-core one component plasma). We calculate the excess free energy of polymer one component plasma in the framework of modified random phase approximation, whereas a contribution of charge densities' fluctuations of neutralizing backgrounds we evaluate at the level of Gaussian approximation. We show that our theory is in a very good agreement with the results of Monte Carlo and MD simulations for critical parameters of liquid-liquid phase separation and osmotic pressure in a wide range of monomer concentration above the critical point, respectively.

  2. Terahertz wave electro-optic measurements with optical spectral filtering

    International Nuclear Information System (INIS)

    We propose electro-optic detection techniques based on variations of the laser pulse spectrum induced during pulse co-propagation with terahertz wave radiation in a nonlinear crystal. Quantitative comparison with two other detection methods is made. Substantial improvement of the sensitivity compared to the standard electro-optic detection technique (at high frequencies) and to the previously shown technique based on laser pulse energy changes is demonstrated in experiment

  3. Electro-optic methods for longitudinal bunch diagnostics at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, B.R.

    2007-07-15

    Precise measurements of the temporal profile of sub-picosecond electron bunches are of high interest for the optimization and operation of VUV and X-ray free electron lasers. In this thesis, the shortest electro-optic signals measured so far for electron bunch diagnostics are presented, reaching a time resolution of better than 50 fs (rms). The e ects that introduce signal distortions and limit the time resolution are studied in numerical simulations for different electro-optic detection materials and techniques. The time resolution is mainly limited by lattice resonances of the electro-optic crystal. Electro-optic signals as short as 54 fs (rms) are obtained with gallium phosphide (GaP) crystals in a crossed polarizer detection scheme using temporally resolved electro-optic detection. Measuring near crossed polarization, where the electro-optic signal is proportional to the velocity field of the relativistic electron bunch, the shortest obtained signal width is 70 fs (rms). The electro-optic signals are compared to electron bunch shapes that are measured simultaneously with a transverse deflecting structure with 20 fs resolution. Numerical simulations using the bunch shapes as determined with the transverse deflecting cavity as input data are in excellent agreement with electro-optical signals obtained with GaP, both for temporally and spectrally resolved measurements. In the case of zinc telluride (ZnTe) the observed signals are slightly broader and significantly smaller than expected from simulations. These discrepancies are probably due to the poor optical quality of the available ZnTe crystals. (orig.)

  4. Terahertz wave electro-optic measurements with optical spectral filtering

    Energy Technology Data Exchange (ETDEWEB)

    Ilyakov, I. E., E-mail: igor-ilyakov@mail.ru; Shishkin, B. V. [Institute of Applied Physic RAS, Nizhny Novgorod 603950 (Russian Federation); Kitaeva, G. Kh. [Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Akhmedzhanov, R. A. [Institute of Applied Physic RAS, Nizhny Novgorod 603950 (Russian Federation); N.I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod 603950 (Russian Federation)

    2015-03-23

    We propose electro-optic detection techniques based on variations of the laser pulse spectrum induced during pulse co-propagation with terahertz wave radiation in a nonlinear crystal. Quantitative comparison with two other detection methods is made. Substantial improvement of the sensitivity compared to the standard electro-optic detection technique (at high frequencies) and to the previously shown technique based on laser pulse energy changes is demonstrated in experiment.

  5. Electro-optical Properties of Ultra-Thin Organic Films

    OpenAIRE

    Hodges, Ping Y.

    2001-01-01

    Electro-optical properties of thin film are of great interest owing to the perpetual demand for miniaturization and higher speed devices for communication, electronic, and biomedical applications. The thickness of polymer films developed for these applications has decreased dramatically making interfacial effects significant. It is well documented that, in submicron thickness range, both film/substrate & film/air interface are critical. In this study, we probe the dynamics of electro-optic...

  6. Electro oxidation of Malachite Green and Modeling Using ANN

    OpenAIRE

    Antony Soloman, P.; Ahmed Basha, C.; Velan, M.; Balasubramanian, N.

    2010-01-01

    This study involves the electro-oxidation of malachite green, a triphenyl methane dye, extensively used in industries and aquaculture, and later banned in most developed countries because of its potential carcinogenicity, mutagenicity and teratogenicity in mammals. The study is conducted in a batch electro-chemical reactor using the catalytic anode (made of noble oxide coated, RuOx-TiOx, titanium expanded mesh) that mediates the oxidation of organic species by the formation of higher oxida...

  7. Application of electro-optic sampling in FEL diagnostics

    International Nuclear Information System (INIS)

    The electro-optic sampling technique has been used for the full characterization (both amplitude and phase) of freely propagating pulsed electromagnetic radiation (such as FEL pulses, transition radiation) and for the quasistatic electric field of relativistic electron bunches. Measurements of the electron bunch length and shape have been performed with both non-intercepting and intercepting methods. Sub-picosecond time resolution has been obtained with this electro-optic detection technique

  8. Application of electro-optic sampling in FEL diagnostics

    CERN Document Server

    Yan, X; Gillespie, W A; Knippels, G M H; Oepts, D; Meer, A F G

    2001-01-01

    The electro-optic sampling technique has been used for the full characterization (both amplitude and phase) of freely propagating pulsed electromagnetic radiation (such as FEL pulses, transition radiation) and for the quasistatic electric field of relativistic electron bunches. Measurements of the electron bunch length and shape have been performed with both non-intercepting and intercepting methods. Sub-picosecond time resolution has been obtained with this electro-optic detection technique.

  9. Electro-optic methods for longitudinal bunch diagnostics at FLASH

    International Nuclear Information System (INIS)

    Precise measurements of the temporal profile of sub-picosecond electron bunches are of high interest for the optimization and operation of VUV and X-ray free electron lasers. In this thesis, the shortest electro-optic signals measured so far for electron bunch diagnostics are presented, reaching a time resolution of better than 50 fs (rms). The e ects that introduce signal distortions and limit the time resolution are studied in numerical simulations for different electro-optic detection materials and techniques. The time resolution is mainly limited by lattice resonances of the electro-optic crystal. Electro-optic signals as short as 54 fs (rms) are obtained with gallium phosphide (GaP) crystals in a crossed polarizer detection scheme using temporally resolved electro-optic detection. Measuring near crossed polarization, where the electro-optic signal is proportional to the velocity field of the relativistic electron bunch, the shortest obtained signal width is 70 fs (rms). The electro-optic signals are compared to electron bunch shapes that are measured simultaneously with a transverse deflecting structure with 20 fs resolution. Numerical simulations using the bunch shapes as determined with the transverse deflecting cavity as input data are in excellent agreement with electro-optical signals obtained with GaP, both for temporally and spectrally resolved measurements. In the case of zinc telluride (ZnTe) the observed signals are slightly broader and significantly smaller than expected from simulations. These discrepancies are probably due to the poor optical quality of the available ZnTe crystals. (orig.)

  10. Weakly polarization dependent electro-optic effect in poled silica

    DEFF Research Database (Denmark)

    Arentoft, Jesper; Pedersen, K.; Bozhevolnyi, Sergey I.;

    1999-01-01

    A ratio between c(2)33 and c(2)31 less than 3 is observed in measurements of the linear electro-optic effect and second-harmonic generation of poled silica.......A ratio between c(2)33 and c(2)31 less than 3 is observed in measurements of the linear electro-optic effect and second-harmonic generation of poled silica....

  11. THz Electro-absorption Effect in Quantum Dots

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Monozon, Boris S.; Livshits, Daniil A.; Rafailov, Edik U.; Hoffmann, Matthias C.

    2011-01-01

    Instantaneous electro-absorption effect in quantum dots, induced by electric field of THz pulse with 3 THz bandwidth is demonstrated in THz pump - optical probe experiment. This effect may be promising for Tbit/s wireless transmission systems.......Instantaneous electro-absorption effect in quantum dots, induced by electric field of THz pulse with 3 THz bandwidth is demonstrated in THz pump - optical probe experiment. This effect may be promising for Tbit/s wireless transmission systems....

  12. Hydrogel Walkers with Electro-Driven Motility for Cargo Transport

    OpenAIRE

    Chao Yang; Wei Wang; Chen Yao; Rui Xie; Xiao-Jie Ju; Zhuang Liu; Liang-Yin Chu

    2015-01-01

    In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two “legs” for walking. The hydrogel walkers can reversibly bend and stretch via repeated “on/off” electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers ...

  13. Proteomic profiling analysis reveals that glutathione system plays important roles responding to osmotic stress in wheat (Triticum aestivum L.) roots.

    Science.gov (United States)

    Ma, Jianhui; Dong, Wen; Zhang, Daijing; Gao, Xiaolong; Jiang, Lina; Shao, Yun; Tong, Doudou; Li, Chunxi

    2016-01-01

    Wheat is one of the most important crops in the world, and osmotic stress has become one of the main factors affecting wheat production. Understanding the mechanism of the response of wheat to osmotic stress would be greatly significant. In the present study, isobaric tag for relative and absolute quantification (iTRAQ) was used to analyze the changes of protein expression in the wheat roots exposed to different osmotic stresses. A total of 2,228 expressed proteins, including 81 differentially expressed proteins, between osmotic stress and control, were found. The comprehensive analysis of these differentially expressed proteins revealed that osmotic stress increased the variety of expressed proteins and suppressed the quantity of expressed proteins in wheat roots. Furthermore, the proteins for detoxifying and reactive oxygen species scavenging, especially the glutathione system, played important roles in maintaining organism balance in response to osmotic stress in wheat roots. Thus, the present study comprehensively describes the protein expression changes in wheat roots in response to osmotic stress, providing firmer foundation to further study the mechanism of osmotic resistance in wheat. PMID:27602297

  14. Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo

    KAUST Repository

    Fujii, Hiroaki

    2011-01-10

    Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved in osmotic stress signaling. However, due to functional redundancy, their contribution to osmotic stress responses remained unclear. In this report, we constructed an Arabidopsis line carrying mutations in all 10 members of the SnRK2 family. The decuple mutant snrk2.1/2/3/4/5/6/7/8/9/10 grew poorly under hyperosmotic stress conditions but was similar to the wild type in culture media in the absence of osmotic stress. The mutant was also defective in gene regulation and the accumulation of abscisic acid (ABA), proline, and inositol 1,4,5-trisphosphate under osmotic stress. In addition, analysis of mutants defective in the ABA-activated SnRK2s (snrk2.2/3/6) and mutants defective in the rest of the SnRK2s (snrk2.1/4/5/7/8/9/10) revealed that SnRK2s are a merging point of ABA-dependent and -independent pathways for osmotic stress responses. These results demonstrate critical functions of the SnRK2s in mediating osmotic stress signaling and tolerance.

  15. Electro-active bio-films: formation, characterization and mechanisms

    International Nuclear Information System (INIS)

    Some bacteria, which are able to exchange electrons with a conductive material without mediator form on conductive surfaces electro-active bio-films. This bacterial property has been recently discovered (2001). Objectives of this work are to develop electro-active bio-films in various natural environments from indigenous flora, then through complementary electrochemical techniques (chrono-amperometry and cyclic voltammetry), to evaluate electro-activity of isolates coming from so-formed bio-films and to characterize mechanisms of electron transfer between bacteria and materials. First, electro-active bio-films have been developed under chrono-amperometry in garden compost and in water coming from Guyana mangrove. These bio-films were respectively able to use an electrode as electron acceptor (oxidation) or as electron donor (reduction). In compost, results obtained in chrono-amperometry and cyclic voltammetry suggest a two-step electron transfer: slow substrate consumption, then rapid electron transfer between bacteria and the electrode. Thereafter, the ability to reduce oxygen was demonstrated with cyclic voltammetry for facultative aerobic isolates from compost bio-films (Enterobacter spp. and Pseudomonas spp.) and for aerobic isolates obtained from marine electro-active bio-films (Roseobacter spp. in majority). Finally, bio-films inducing current increase in chrono-amperometry were developed in bioreactor with synthetic medium from a pure culture of isolates. Hence, for the first time, electro-activity of several anaerobic strains of Geobacter bremensis isolated from compost bio-films was highlighted. (author)

  16. Electro-thermography technique for nondestructive testing (NDT) applications

    Science.gov (United States)

    Chen, Y. S.; Hung, Y. Y.; Liu, L.

    2008-11-01

    In this paper, Electro-Thermography is introduced in nondestructive testing applications. Electro-Thermography is one of the novel active thermography techniques for nondestructive testing. It gains the advantages from the optical and electromagnetic properties in full-field, non-contact, high inspection speed, and sensitivity in geometry variation. It is mostly applicable to all kind of ferrous-metal, some composites materials. A fundamental difference among electro-thermography and other active thermography techniques are the excitation mechanism. Electro-Thermography is a combination of the electromagnetic induction and surface thermal radiation measuring technique; it used the induction method to excite the object, and then it used the radiation properties to measure the distribution of surface temperature of the object. It detects flaws by the flaw's anomalous heating and heat transfer response. The method of excitation is also different from others irradiation excitation. Electro-Thermography needs an electromagnetic coil to generate eddy current through induction to change the surface and subsurface temperature. Electro-Thermography can detect surface and sub-surface flaws, unless the flaw is too remote and tiny from the surface. Some experiments in flaw detections and other types of inspections are demonstrated.

  17. New method to improve dynamic stiffness of electro-hydraulic servo systems

    Science.gov (United States)

    Bai, Yanhong; Quan, Long

    2013-09-01

    Most current researches working on improving stiffness focus on the application of control theories. But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated, so the control action is lagged. Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms. In this paper, the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed. On this basis, the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward. And a scheme using double servo valves to realize flow feedforward compensation is presented, in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time. The two valves are arranged in parallel to control the cylinder jointly. Furthermore, the model of flow compensation is derived, by which the product of the amplitude and width of the valve’s pulse command signal can be calculated. And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations. Using the proposed scheme, simulations and experiments at different positions with different force changes are conducted. The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time. That is, system dynamic load stiffness is evidently raised. This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

  18. Investigation of quadratic electro-optic effects and electro-absorption process in GaN/AlGaN spherical quantum dot

    OpenAIRE

    Kouhi, Mohammad; Vahedi, Ali; Akbarzadeh, Abolfazl; Hanifehpour, Younes; Joo, Sang Woo

    2014-01-01

    Quadratic electro-optic effects (QEOEs) and electro-absorption (EA) process in a GaN/AlGaN spherical quantum dot are theoretically investigated. It is found that the magnitude and resonant position of third-order nonlinear optical susceptibility depend on the nanostructure size and aluminum mole fraction. With increase of the well width and barrier potential, quadratic electro-optic effect and electro-absorption process nonlinear susceptibilities are decreased and blueshifted. The results sho...

  19. Electro-active sensor, method for constructing the same; apparatus and circuitry for detection of electro-active species

    Science.gov (United States)

    Buehler, Martin (Inventor)

    2009-01-01

    An electro-active sensor includes a nonconductive platform with a first electrode set attached with a first side of a nonconductive platform. The first electrode set serves as an electrochemical cell that may be utilized to detect electro-active species in solution. A plurality of electrode sets and a variety of additional electrochemical cells and sensors may be attached with the nonconductive platform. The present invention also includes a method for constructing the aforementioned electro-active sensor. Additionally, an apparatus for detection and observation is disclosed, where the apparatus includes a sealable chamber for insertion of a portion of an electro-active sensor. The apparatus allows for monitoring and detection activities. Allowing for control of attached cells and sensors, a dual-mode circuitry is also disclosed. The dual-mode circuitry includes a switch, allowing the circuitry to be switched from a potentiostat to a galvanostat mode.

  20. Propagation of electro-kinetic waves in magnetized GaN semiconductor with nano-sized ion colloids

    International Nuclear Information System (INIS)

    Based on hydrodynamic model of multi-component plasma, an analytical study on propagation of longitudinal electro-kinetic (LEK) waves in wurtzite and zincblende structures of GaN is carried out. Nano-sized ion colloids (NICs) are embedded in the sample by the technique of ion-implantation. The implanted NICs are considered massive by an order as compared to the host lattice points and do not participate in Based LEK perturbations. Though, the NICs are continuously bombarded by the electrons as well as the holes yet, the former acquires a net negative charge owing to relatively higher mobility of electrons and consequently results into depletion of electron density in the medium. It i s found that the presence of charged NICs significantly modifies the dispersion and amplification characteristics of LEK waves in magnetized GaN semiconductor plasma and their role becomes increasingly effective as the fraction of charge on them increases

  1. Research progress on space charge characteristics in polymeric insulation

    Science.gov (United States)

    Zhang, Yibo; Christen, Thomas; Meng, Xing; Chen, Jiansheng; Rocks, Jens

    2016-03-01

    Due to their excellent electrical insulation properties and processability, polymer materials are used in many electrical products. It is widely believed that space charge plays an important role for the electric field distribution, conduction, ageing, and electric breakdown of polymeric insulation. This paper reviews measurements and characteristics of space charge behavior which mainly determined by the pulsed electro-acoustic (PEA) measurement technique. Particular interests are the effects of the applied voltage, the electrodes, temperature, humidity, microstructure, additives, and filler materials on accumulation, distribution, transport, and the decay of space charge in polymeric materials. This review paper is to provide an overview on various space charge effects under different conditions, and also to summarize the information for polymeric materials with suppressed space charge and improved electrical behavior.

  2. Infl uence of thermal treatment on the stability of phenolic compounds and the microbiological quality of sucrose solution following osmotic dehydration of highbush blueberry fruits

    OpenAIRE

    Anna Kucner; Agnieszka Papiewska; Robert Klewicki; Michał Sójka; Elżbieta Klewicka

    2014-01-01

    Background. Osmotic dehydration is a process of the partial removal of water which is based on immersion of material having cellular structure in a hypertonic solution. Osmotic dehydration is used as a pretreatment for the dehydration of foods before they are subjected to further processing such as freezing, freeze drying, vacuum drying. Management of spent syrup is one of the most important problems related to osmotic dewatering. Osmotic solutions are heavily polluted with of carbohydrates, ...

  3. Electro-mechanical resonant magnetic field sensor

    International Nuclear Information System (INIS)

    We describe a new type of magnetic field sensor, which is termed as an Electro-Mechanical Resonant Sensor (EMRS). The key part of this sensor is a small conductive elastic element with low damping rate and therefore, a high Q fundamental mode of frequency f1. An AC current is driven through the elastic element which, in the presence of a magnetic field, causes an AC force on the element. When the frequency of the AC current matches the resonant frequency of the element, maximum vibration of the element occurs and this can be measured precisely by optical means. We have built and tested a model sensor of this type by using for the elastic element, a length of copper wire of diameter 0.030 mm formed into a loop shape. The wire motion was measured using a light-emitting diode photo-transistor assembly. This sensor demonstrated a sensitivity better than 0.001 G for an applied magnetic field of ∼1 G and a good selectivity for the magnetic field direction. The sensitivity can be easily improved by a factor of ∼10-100 by a more sensitive measurement of the elastic element motion and by having the element in vacuum to reduce the drag force

  4. Quantum electro-mechanical system (QEMS)

    International Nuclear Information System (INIS)

    Full text: Recent development in Nano Electro-Mechanical Systems (NEMS) has yield oscillators with resonant frequencies above Giga Hertz with quality factors above 100,000. At this scale a NEMS oscillator becomes a quantum device capable of operating at the atomic level with extraordinary sensitivity to small forces or molecular masses. With this motivation, we study the phonon-electron interaction in several quantum electromechanical systems (QEMS). First, a system comprising a single quantum dot harmonically bound between two electrodes which facilitates a tunneling current between them and secondly the electron shuttle system firstly introduced by Gorelik. We describe the system via quantum master equation for the density operator of the electronic and vibrational degrees of freedom and thus incorporates the dynamics of both diagonal (population) and off diagonal (coherence) terms. We derive coupled equations of motion for the electron occupation number of the dot and the vibrational degrees of freedom, including damping of the vibration and thermo-mechanical noise. This dynamical description is related to observable features of the system including the stationary current as a function of bias voltage. A number of possible applications are explored for feasibility including molecular QEMS devices as quantum limited nanoscale detectors and as elements in quantum computer architectures. Copyright (2005) Australian Institute of Physics

  5. Asymptotic behaviour of electro-$\\Lambda$ spacetimes

    CERN Document Server

    Saw, Vee-Liem

    2016-01-01

    We derive the asymptotic solutions for vacuum spacetimes with non-zero cosmological constant $\\Lambda$ coupled to Maxwell fields, using the Newman-Penrose formalism. This extends a recent work that dealt with the vacuum Einstein (Newman-Penrose) equations with $\\Lambda=0$. Using these asymptotic solutions, we discuss the mass-loss of an isolated electro-gravitating system with cosmological constant. In a universe with $\\Lambda>0$, the physics of electromagnetic (EM) radiation is relatively straightforward compared to those of gravitational radiation: 1) It is clear that outgoing EM radiation results in a decrease to the Bondi mass of the isolated system. 2) It is also perspicuous that if any incoming EM radiation from elsewhere is present, those beyond the isolated system's cosmological horizon would eventually arrive at the spacelike $\\mathcal{I}$ and increase the Bondi mass of the isolated system. Hence, the (outgoing and incoming) EM radiation fields do not couple with the Bondi mass-loss formula in any un...

  6. Highly Sensitive Electro-Optic Modulators

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, Peter S [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  7. Micro-needle electro-tactile display.

    Science.gov (United States)

    Tezuka, Mayuko; Kitamura, Norihide; Miki, Norihisa

    2015-08-01

    Haptic feedback is strongly demanded for high-precision robot-assisted surgery and teleoperation. The haptic feedback consists of force and tactile feedback, however tactile feedback has been little studied and the size and weight of the system poses challenges for practical applications. In this paper we propose a sheet-type wearable electro-tactile display which provides tactile sensations to the user as the feedback at a low voltage and power consumption. The display possesses needle-shaped electrodes, which can penetrate through the high-impedance stratum corneum. We developed the fabrication process and, as the first step, we investigated the tactile sensation that can be created to the fingertip by the display. Rough and smooth surfaces were successfully presented to the user. Then, we characterized the tactile display when used on the forearm, in particular, with respect to the spatial resolution. These tactile displays can be used to inform the user of the surface property of the parts of interest, such as tumor tissues, and to guide him in the manipulation of surgery robots. PMID:26737606

  8. Optimisation of electro discharge machining parameters

    Directory of Open Access Journals (Sweden)

    R.A. Mahdavinejad

    2008-04-01

    Full Text Available Purpose: Electro discharge machining (EDM is one of the most effective non-conventional machining methods. This method is the best condidate in machining of ceramics and carbide materials.Design/methodology/approach: The complexity and non-linear nature of EDM from one side, and occurrence of instability phenomenon due to the different input setting up parameters especially in machining of carbon-based materials such as non-oxide ceramics, on the other side, make the modeling of EDM process impossible with conventional methods. What is presented in this paper is the optimization and control of EDM process using the neural model predictive control method.Findings: The results of implementation of control system on a sinking ED machine and an EDM system that has been set with an expert user, has been compared.Research limitations/implications: To achieve instantaneous data from machining condition, the new method of fuzzy analysis of single machining pulses and computing the magnitude of system condition in the form of a real number between 0 and 1, has been used.Originality/value: The testing results from ED machining of WC-Co confirms the capability of the system of predictive controller model based on neural network with 32.8% efficiency increasing in stock removal rate.

  9. Analysis of Electro-Electro Transmission Efficiency of SAW IDTs System by Six-Port Equivalent Circuit Model

    Institute of Scientific and Technical Information of China (English)

    CHENMing; TANGTiantong; CHENGuangde; ZHANGPenghui

    2003-01-01

    Analysis of electro - electro power transmission efficiency of SAW IDTs (Surface-acoustic-wave Interdigital transducers) system is studied, which is based on the newly developed simple six-port equivalent circuit model for SAW IDTs. The application of this method to the SAW IDTs with 80 fingers system on Y-Z LiNbO3 for acousto-optical interaction is also investigated, and it shows that the calculated result is in agreement with experimental one.

  10. Pre-desalination with electro-membranes for SWRO

    NARCIS (Netherlands)

    Post, J.W.; Huiting, H.; Cornelissen, E.R.; Hamelers, H.V.M.

    2011-01-01

    Although seawater reverse osmosis (SWRO) is currently the only non-thermal desalination process in practical use, its characteristics make it difficult to approach the ideal reversible process. SWRO has a low water recovery (determined by the osmotic pressure) and relatively high energy consumption.

  11. On the calculation of the structure of charge-stabilized colloidal dispersions using density-dependent potentials

    International Nuclear Information System (INIS)

    The structure of charge-stabilized colloidal dispersions has been studied through a one-component model using a Yukawa potential with density-dependent parameters examined with integral equation theory and Monte Carlo simulations. Partial thermodynamic consistency was guaranteed by considering the osmotic pressure of the dispersion from the approximate mean-field renormalized jellium and Poisson-Boltzmann cell models. The colloidal structures could be accurately described by the Ornstein-Zernike equation with the Rogers-Young closure by using the osmotic pressure from the renormalized jellium model. Although we explicitly show that the correct effective pair-potential obtained from the inverse Monte Carlo method deviates from the Yukawa shape, the osmotic pressure constraint allows us to have a good description of the colloidal structure without losing information on the system thermodynamics. Our findings are corroborated by primitive model simulations of salt-free colloidal dispersions. (paper)

  12. Electro-deoxidation of hafnium dioxide and niobia-doped hafnium dioxide in molten calcium chloride

    International Nuclear Information System (INIS)

    Highlights: ► We studied the electro-deoxidation of pure and niobium doped hafnium dioxide. ► The reduction of pure HfO2 was blocked in the core of the pellet associated with the formation of long-ordered CaHfO3 crystals. ► Doping the initial precursor with niobium ions increased the oxygen ion conductivity of CaHfO3. ► Cubes of Hf–Nb alloy powder was produced with 0.8 wt.% oxygen content and 5–20 μm size. - Abstract: This paper investigates the capability of the FFC-Cambridge process of producing metallic hafnium powder that can meet commercial standards. The results show that the reduction in the core of the pellet is hindered in an intermediate step associated with the formation of CaHfO3. Doping the initial hafnium oxide with niobium oxides in the initial pellet prevents this blocking. The charge passed is much higher than that observed with undoped HfO2. The powder obtained after 36 h of electro-deoxidation is an Hf–Nb alloy cubes with 0.8 wt.% oxygen content and 5–20 μm size.

  13. Electro-optic sampling for time resolving relativistic ultrafast electron diffraction

    International Nuclear Information System (INIS)

    The Pegasus laboratory at UCLA features a state-of-the-art electron photoinjector capable of producing ultrashort (<100 fs) high-brightness electron bunches at energies of 3.75 MeV. These beams recently have been used to produce static diffraction patterns from scattering off thin metal foils, and it is foreseen to take advantage of the ultrashort nature of these bunches in future pump-probe time-resolved diffraction studies. In this paper, single shot 2-d electro-optic sampling is presented as a potential technique for time of arrival stamping of electron bunches used for diffraction. Effects of relatively low bunch charge (a few 10's of pC) and modestly relativistic beams are discussed and background compensation techniques to obtain high signal-to-noise ratio are explored. From these preliminary tests, electro-optic sampling is suitable to be a reliable nondestructive time stamping method for relativistic ultrafast electron diffraction at the Pegasus lab.

  14. Mechanistic studies of water electrolysis and hydrogen electro-oxidation on high temperature ceria-based solid oxide electrochemical cells.

    Science.gov (United States)

    Zhang, Chunjuan; Yu, Yi; Grass, Michael E; Dejoie, Catherine; Ding, Wuchen; Gaskell, Karen; Jabeen, Naila; Hong, Young Pyo; Shavorskiy, Andrey; Bluhm, Hendrik; Li, Wei-Xue; Jackson, Gregory S; Hussain, Zahid; Liu, Zhi; Eichhorn, Bryan W

    2013-08-01

    Through the use of ambient pressure X-ray photoelectron spectroscopy (APXPS) and a single-sided solid oxide electrochemical cell (SOC), we have studied the mechanism of electrocatalytic splitting of water (H2O + 2e(-) → H2 + O(2-)) and electro-oxidation of hydrogen (H2 + O(2-) → H2O + 2e(-)) at ∼700 °C in 0.5 Torr of H2/H2O on ceria (CeO2-x) electrodes. The experiments reveal a transient build-up of surface intermediates (OH(-) and Ce(3+)) and show the separation of charge at the gas-solid interface exclusively in the electrochemically active region of the SOC. During water electrolysis on ceria, the increase in surface potentials of the adsorbed OH(-) and incorporated O(2-) differ by 0.25 eV in the active regions. For hydrogen electro-oxidation on ceria, the surface concentrations of OH(-) and O(2-) shift significantly from their equilibrium values. These data suggest that the same charge transfer step (H2O + Ce(3+) Ce(4+) + OH(-) + H(•)) is rate limiting in both the forward (water electrolysis) and reverse (H2 electro-oxidation) reactions. This separation of potentials reflects an induced surface dipole layer on the ceria surface and represents the effective electrochemical double layer at a gas-solid interface. The in situ XPS data and DFT calculations show that the chemical origin of the OH(-)/O(2-) potential separation resides in the reduced polarization of the Ce-OH bond due to the increase of Ce(3+) on the electrode surface. These results provide a graphical illustration of the electrochemically driven surface charge transfer processes under relevant and nonultrahigh vacuum conditions. PMID:23822749

  15. Osmotic Gradients Induce Bio-reminiscent Morphological Transformations in Giant Unilamellar Vesicles

    Directory of Open Access Journals (Sweden)

    KamilaOglecka

    2012-05-01

    Full Text Available We report observations of large-scale, in-plane and out-of-plane membrane deformations in giant uni- and multilamellar vesicles composed of binary and ternary lipid mixtures in the presence of net transvesicular osmotic gradients. The lipid mixtures we examined consisted of binary mixtures of DOPC and DPPC lipids and ternary mixtures comprising POPC, sphingomyelin, and cholesterol over a range of compositions – both of which produce co-existing phases for selected ranges of compositions at room temperature under thermodynamic equilibrium. In the presence of net osmotic gradient, we find that the in-plane phase separation potential of these mixtures is non-trivially altered and a variety of out-of-plane morphological remodeling occurs. The repertoire of membrane deformations we observe display striking resemblance to their biological counterparts in live cells encompassing vesiculation, membrane fission and fusion, tubulation and pearling, as well as expulsion of entrapped vesicles from multicompartmental GUV architectures through large, self-healing transient pores. These observations suggest that the forces introduced by simple osmotic gradients across membrane boundaries could act as a trigger for shape-dependent membrane and vesicle trafficking activities. We speculate that such coupling of osmotic gradients with membrane properties might have provided lipid-mediated mechanisms during the early evolution of membrane compartmentalization in the absence of osmoregulatory protein machinery.

  16. Osmotic Pressure in the Physics Course for Students of the Life Sciences

    Science.gov (United States)

    Hobbie, Russell K.

    1974-01-01

    Discusses the use of an ideal gas model to explain osmotic equilibrium and nonequilibrium flows through an ideal semipermeable membrane. Included are a justification of the relationship between an ideal gas and a dilute solution, a review of the irreversible thermodynamic flow, and some sample applications to physiology. (CC)

  17. Relationship between osmotic pressure of the blood and secretion of sweat

    Science.gov (United States)

    Montuori, A.

    1978-01-01

    Experiments with cats show that the thermic secretion of sweat represents a specific case of a general law: The central nervous apparatus that controls the secretion of sweat begins to function when the osmotic pressure of the blood drops below normal.

  18. Effect of process variables on the osmotic dehydration of star-fruit slices

    Directory of Open Access Journals (Sweden)

    Camila Dalben Madeira Campos

    2012-06-01

    Full Text Available The objective of this work was to study the effect of blanching and the influence of temperature, solution concentration, and the initial fruit:solution ratio on the osmotic dehydration of star-fruit slices. For blanching, different concentrations of citric and ascorbic acids were studied. The samples immersed in 0.75% citric acid presented little variation in color in relation to the fresh star-fruit. Osmotic dehydration was carried out in an incubator with orbital shaking, controlled temperature, and constant shaking at 120 rpm. The influence of process variables was studied in trials defined by a complete 23 central composite design. In general, water loss and solids gain were positively influenced by temperature and by solution concentration. Nevertheless, lower temperatures reduced water loss throughout the osmotic dehydration process. An increase in the amount of dehydrating solution (initial fruit:solution ratio slightly influenced the evaluated responses. The process carried out at 50 ºC with a solution concentration of 50% resulted in a product with lower solids gain and greater water loss. Under these conditions, blanching minimized the effect of the osmotic treatment on star-fruit browning, and therefore the blanched fruits showed little variation in color in relation to the fresh fruit.

  19. Osmotic pressure and aggregate shape in BSA/Poly(Ethylene Glycol)-Lipid/Dextran solutions

    OpenAIRE

    Castelletto, Valeria; Hamley, Ian W.; Clifton, Luke. A.; Green, Rebecca J.

    2008-01-01

    Osmotic pressure and aggregate shape in BSA/Poly(Ethylene Glycol)-Lipid/Dextran solutions correspondance: Corresponding author. Tel.: +44 113 343 7595; fax: +44 113 343 6551. (Castelletto, Valeria) (Castelletto, Valeria) School of Chemistry--> , Food Biosciences and Pharmacy--> , The University of Reading--> , P.O. Box 226--> , Whiteknights--> , Reading--> - UNIT...

  20. Effect of Pulsed Electric Field Pre-Treatment on Osmotic Dehydration of Strawberries

    Science.gov (United States)

    The objective of this research was to study the effect of pulsed electric fields (PEF) as a pre-treatment on osmotic dehydration characteristics and quality of strawberries. The studied PDF treatment conditions included three strengths of electric field (1.0, 2.0, 3.0 Kw/cm) and three numbers of pu...