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Sample records for suspended smectic liquid

  1. Mutual diffusion of inclusions in freely suspended smectic liquid crystal films.

    Science.gov (United States)

    Qi, Zhiyuan; Nguyen, Zoom Hoang; Park, Cheol Soo; Glaser, Matthew A; Maclennan, Joseph E; Clark, Noel A; Kuriabova, Tatiana; Powers, Thomas R

    2014-09-19

    We study experimentally and theoretically the hydrodynamic interaction of pairs of circular inclusions in two-dimensional, fluid smectic membranes suspended in air. By analyzing their Brownian motion, we find that the radial mutual mobilities of identical inclusions are independent of their size but that the angular coupling becomes strongly size dependent when their radius exceeds a characteristic hydrodynamic length. These observations are described well for arbitrary inclusion separations by a model that generalizes the Levine-MacKintosh theory of point-force response functions and uses a boundary-element approach to calculate the mobility matrix for inclusions of finite extent.

  2. Diffusion processes in freely suspended smectic films

    Science.gov (United States)

    Śliwa, I.; Zakharov, A. V.

    2017-08-01

    A molecular model describing translational diffusion in freely suspended smectic films (FSSFs) in air is proposed. This model is based on the random walk theory and allows calculation of the translational diffusion coefficient (TDC) across smectic layers (along the director). All values necessary for calculating the TDC are obtained within the generalized mean-field model considering not only anisotropic interactions between nearest neighbors of molecules forming FSSFs, but also the stabilizing effect of the smectic/air interface. The spatial inhomogeneity of order parameters over the FSSF section, arising in this case, results in the fact that the surface tension at the smectic/air interface not only suppresses thermal fluctuations in surface layers, but also completely suppresses translational diffusion of molecules from the FSSF to air. The results of calculations of dimensional translational diffusion in the bulk of the FSSF formed by 5- n-alkyl-2-(4- n-(perfluoroalkyl-metyleneoxy))pentyl molecules during its thinning show that the TDC monotonically increases as the smectic film is thinned.

  3. Smectic phases in ionic liquid crystals.

    Science.gov (United States)

    Bartsch, Hendrik; Bier, Markus; Dietrich, S

    2017-11-22

    Ionic liquid crystals (ILCs) are anisotropic mesogenic molecules which carry charges and therefore combine properties of liquid crystals, e.g. the formation of mesophases, and of ionic liquids, such as low melting temperatures and tiny triple-point pressures. Previous density functional calculations have revealed that the phase behavior of ILCs is strongly affected by their molecular properties, i.e. their aspect ratio, the loci of the charges, and their interaction strengths. Here, we report new findings concerning the phase behavior of ILCs as obtained by density functional theory and Monte Carlo simulations. The most important result is the occurrence of a novel, wide smectic-A phase [Formula: see text], at low temperature, the layer spacing of which is larger than that of the ordinary high-temperature smectic-A phase [Formula: see text]. Unlike the ordinary smectic S A phase, the structure of the [Formula: see text] phase consists of alternating layers of particles oriented parallel to the layer normal and oriented perpendicular to it.

  4. Spontaneous Ferroelectric Order in a Bent-Core Smectic Liquid Crystal of Fluid Orthorhombic Layers

    Energy Technology Data Exchange (ETDEWEB)

    R Reddy; C Zhu; R Shao; E Korblova; T Gong; Y Shen; M Glaser; J Maclennan; D Walba; N Clark

    2011-12-31

    Macroscopic polarization density, characteristic of ferroelectric phases, is stabilized by dipolar intermolecular interactions. These are weakened as materials become more fluid and of higher symmetry, limiting ferroelectricity to crystals and to smectic liquid crystal stackings of fluid layers. We report the SmAP{sub F}, the smectic of fluid polar orthorhombic layers that order into a three-dimensional ferroelectric state, the highest-symmetry layered ferroelectric possible and the highest-symmetry ferroelectric material found to date. Its bent-core molecular design employs a single flexible tail that stabilizes layers with untilted molecules and in-plane polar ordering, evident in monolayer-thick freely suspended films. Electro-optic response reveals the three-dimensional orthorhombic ferroelectric structure, stabilized by silane molecular terminations that promote parallel alignment of the molecular dipoles in adjacent layers.

  5. Final Report: Biaxiality in Nematic and Smectic Liquid Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Satyendra; Quan, Li; Srinivasarao, Mohan; Agra-Kooijman, Dena; Rey, Alejandro

    2017-01-24

    During the award period, the project team explored several phenomena in a diverse group of soft condensed matter systems. These include understanding of the structure of the newly discovered twist-bend nematic phase, solving the mystery of de Vries smectic phases, probing of interesting associations and defect structures in chromonic liquid crystalline systems, dispersions of ferroelectric nanoparticles in smectic liquid crystals, investigations of newly synthesized light sensitive and energy harvesting materials with highly desirable transport properties. Our findings are summarized in the following report followed by a list of 36 publications and 37 conference presentations. We achieved this with the support of Basic Sciences Division of the US DOE for which we are thankful.

  6. Molecular simulation of chevrons in confined smectic liquid crystals

    Science.gov (United States)

    Webster, Richard E.; Mottram, Nigel J.; Cleaver, Douglas J.

    2003-08-01

    Chevron structures adopted by confined smectic liquid crystals are investigated via molecular dynamics simulations of the Gay-Berne model. The chevrons are formed by quenching nematic films confined between aligning planar substrates whose easy axes have opposing azimuthal components. When the substrates are perfectly smooth, the chevron formed migrates rapidly towards one of the confining walls to yield a tilted layer structure. However, when substrate roughness is included, by introducing a small-amplitude modulation to the particle-substrate interaction well depth, a symmetric chevron is formed which remains stable over sufficiently long run times for detailed structural information, such as the relevant order parameters and director orientation, to be determined. For both smooth and rough boundaries, the smectic order parameter remains nonzero across the entire chevron, implying that layer identity is maintained across the chevron tip. Also, when the surface-stabilized chevron does eventually revert to a tilted layer structure, it does so via surface slippage, such that layer integrity is maintained throughout the chevron to tilted layer relaxation process.

  7. Observation of Algebraic Decay of Positional Order in a Smectic Liquid Crystal

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage; Litster, J. D.; Birgeneau, R. J.

    1980-01-01

    A smectic-A liquid crystal in three dimensions has been predicted to exhibit algebraic decay of the layer correlations rather than true long-range order. As a consequence, the smectic Bragg peaks are expected to be power-law singularities of the form q∥-2+η and q⊥-4+2η, where ∥(⊥) is along...... (perpendicular to) the smectic density wave vector direction, rather than δ function peaks. Observation of these phenomena requires very high instrumental resolution together with a resolution function with wings which drop off much more rapidly than q∥-2(q⊥-4). We show that these requirements may be met...... by using a three crystal x-ray spectrometer with multiple-reflection channel cut crystals as monochromator and analyzer. We find that the smectic-A Bragg peaks observed in the liquid-crystal octyloxy-cyanobiphenyl are indeed consistent with the predicted power-law singularity form. Furthermore...

  8. Smectic elastomer membranes

    OpenAIRE

    Stenull, Olaf

    2007-01-01

    We present a model for smectic elastomer membranes which includes elastic and liquid crystalline degrees of freedom. Based on our model, we determined the qualitative phase diagram of a smectic elastomer membrane using mean-field theory. This phase diagram is found to comprise five phases, viz. smectic-A--flat, smectic-A--crumpled, smectic-C--flat, smectic-C--crumpled and smectic-C--tubule, where in the latter phase, the membrane is flat in the direction of mesogenic tilt and crumpled in the ...

  9. Facilitated Ion Transport in Smectic Ordered Ionic Liquid Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Hong [Materials Architecturing Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5 Seongbuk-gu Seoul 136-791 South Korea; School of Chemical and Biological Engineering and Institute of Chemical Process, Seoul National University, 599 Gwanak-ro Gwanak-gu Seoul 151-742 South Korea; Han, Kee Sung [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland WA 99354 USA; Lee, Je Seung [Department of Chemistry, Kyung Hee University, 26 Kyungheedae-ro Dongdaemun-gu Seoul 02447 South Korea; Lee, Albert S. [Materials Architecturing Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5 Seongbuk-gu Seoul 136-791 South Korea; Park, Seo Kyung [Department of Chemistry, Kyung Hee University, 26 Kyungheedae-ro Dongdaemun-gu Seoul 02447 South Korea; Hong, Sung Yun [Department of Chemistry, Kyung Hee University, 26 Kyungheedae-ro Dongdaemun-gu Seoul 02447 South Korea; Lee, Jong-Chan [School of Chemical and Biological Engineering and Institute of Chemical Process, Seoul National University, 599 Gwanak-ro Gwanak-gu Seoul 151-742 South Korea; Mueller, Karl T. [Department of Chemistry, Pennsylvania State University, University Park PA 16802 USA; Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland WA 99352 USA; Hong, Soon Man [Materials Architecturing Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5 Seongbuk-gu Seoul 136-791 South Korea; Nanomaterials Science and Engineering, University of Science and Technology, Gajeong-ro Yuseong-gu Daejeon 305-350 South Korea; Koo, Chong Min [Materials Architecturing Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5 Seongbuk-gu Seoul 136-791 South Korea; Nanomaterials Science and Engineering, University of Science and Technology, Gajeong-ro Yuseong-gu Daejeon 305-350 South Korea

    2016-09-08

    We investigated a novel ionic mixture of an imidazolium-based room temperature IL containing ethylene oxide functionalized phosphite anion and a lithium salt that self-assembles into a smectic-ordered IL crystal. The two key features in this work are the unique origin of the smectic order of the ionic mixtures and the facilitated ion transport behavior in the smectic ordered IL crystal. In fact, the IL crystals are self-assembled through Coulombic interactions between ion species, not through the hydrophilic-phobic interactions between charged ion heads and hydrophobic long alkyl pendants or the steric interaction between mesogenic moieties. Furthermore, the smectic order in the IL crystal ionogel facilitates exceptional and remarkable ionic transport. Large ionic conductivity, viscoelastic robustness, and additional electrochemical stability of the IL crystal ionogels provide promising opportunities for future electrochemical applications.

  10. Modulations and Fluctuations in Lyotropic Smectic Liquid Crystals.

    Science.gov (United States)

    Wack, Daniel Christopher

    This dissertation is concerned with modulation and fluctuation phenomena in lyotropic smectic liquid crystals. The first Chapter provides a critical summary of the results and suggestions for further experimental investigation. In Chapter 2, the results of a high resolution, synchrotron x-ray powder diffraction study of lattice constants in the P_{beta^' } ("rippled") phase of lecithin-water multilamellar mixtures are given. The variation with water volume fraction phi_{omega} and hydrocarbon chain length N_{c} of the modulation wavevector suggests that membrane curvature and hydration interactions between membranes play a significant role in the modulation. The results are consistent with a Lifshitz phenomenological model for lamellar phases of interacting membranes proposed by Goldstein and Leibler. The phase behavior predicted by the model includes a multicritical point called the Lifshitz Point where the wavelength of the modulation diverges. The experimental results indicate that this multicritical point lies in the vicinity of N_{c} = 9 and phi_{omega} = 0.18. In Chapter 3, a high-resolution synchrotron x-ray study of oriented, supported, hydrated dilaurylphosphatidylcholine in the L_{alpha} (Smectic A or "fluid") phase shows that thermal fluctuations give rise to algebraic decay of positional order in stacking of the bimolecular lamellae, the so-called "Landau-Peierls" state. For planar monocrystalline samples of thickness 10-20 mum, the exponents derived from intensity profiles are in accord with harmonic theory, and indicate a bulk compressional elastic constant B = (1.9 +/- 1.0) x 10 ^8erg/cm^3. Samples of thickness ~ 1-2 mu m show anomalous behavior in the wings of the longitudinal intensity profiles, but are not in accord with harmonic theory, suggesting that surface effects partially quench the thermal fluctuations. In Chapter 4, investigation of the dipalmitoylphosphatidylcholine-cholesterol phase diagram by low and high resolution synchrotron x

  11. Configuration of a smectic A liquid crystal due to an isolated edge dislocation.

    Science.gov (United States)

    Snow, B C; Stewart, I W

    2017-05-17

    We discuss the static configuration of a smectic A liquid crystal subject to an edge dislocation under the assumption that the director and layer normal fields ([Formula: see text] and [Formula: see text], respectively) defining the smectic arrangement are not, in general, equivalent. After constructing the free energy for the smectic, we obtain exact solutions to the equilibrium equations which result from its minimisation at quadratic order in the variables which describe the distortion, and hence a complete description of the smectic configuration across the domain of the sample. We also examine the effect of relaxing the constraint [Formula: see text] for different values of the constants which characterise the response of the material to distortions, and compare these results with the 'classical' case considered by previous authors, in which equivalence of [Formula: see text] and [Formula: see text] is enforced.

  12. Binary mixtures of hydrogen-bonded ferroelectric liquid crystals. Thermal span enhancement in smectic X* phase

    Energy Technology Data Exchange (ETDEWEB)

    Sangameswari, Gopal; Prabu, Nataraj Pongali Sathya; Madhu Mohan, Mathukumalli Lakshmi Narayana [Bannari Amman Institute of Technology, Sathyamangalam (India). Liquid Crystal Research Laboratory (LCRL)

    2015-07-01

    Thermotropic hydrogen-bonded ferroelectric binary liquid crystal mixtures comprising of N-carbamyl-l-glutamic acid (CGA) and p-n-alkyloxy benzoic acids (BAO) are investigated. Variation in the molar proportion of X and Y (where X=CGA+5BAO and Y=CGA+9BAO, CGA+10BAO, CGA+11BAO, and CGA+12BAO) comprising of four series yielded 36 binary mixtures. Optical and thermal properties of these mixtures are meticulously studied in the present article. In addition to the traditional phases, a novel smectic ordering namely smectic X* is observed in all the four series. The aim of the investigation is to obtain abundance occurrence of smectic X* with a large thermal span, and hence, the proportions of the binary mixtures are so chosen that the prelude task is accomplished. Optical tilt angle in smectic X* and smectic C* phases is experimentally determined, and a theoretical fit is performed. Phase diagrams of the four series are constructed from the data obtained from the differential scanning calorimetry and correlated with the phases recorded by the polarising optical microscope studies. Thermal stability factor and thermal equilibrium are also premeditated.

  13. Photoimaging on an optically anisotropic film with a polymerizable smectic liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ji Young; Nam, Sang Woon; Hong, Chong Gi [Seoul National Univ. (Korea). School of Materials Science and Engineering; Seoul National Univ. (Korea). Hyperstructured Organic Materials Research Center; Im, Jung Hyuk; Kim, Jae Ho; Han, Man Jung [Ajou Univ., Suwon (Korea). Dept. of Molecular Science and Technology

    2001-09-03

    The orientation under an electric field of a smectic A phase liquid crystal (LC) is unveiled in this communication. The authors have prepared a rod-like LC consisting of two photoreactive chalcone units and have carried out photopolymerization by UV irradiation. Applications of this technique may include microscopic patterning. (orig.)

  14. Self-organized arrays of dislocations in thin smectic liquid crystal films.

    Science.gov (United States)

    Coursault, Delphine; Zappone, Bruno; Coati, Alessandro; Boulaoued, Athmane; Pelliser, Laurent; Limagne, Denis; Boudet, Nathalie; Ibrahim, Bicher Haj; de Martino, Antonello; Alba, Michel; Goldmann, Michel; Garreau, Yves; Gallas, Bruno; Lacaze, Emmanuelle

    2016-01-21

    Combining optical microscopy, synchrotron X-ray diffraction and ellipsometry, we studied the internal structure of linear defect domains (oily streaks) in films of a smectic liquid crystal 8CB with thicknesses in the range of 100-300 nm. These films are confined between air and a rubbed PVA polymer substrate which imposes hybrid anchoring conditions (normal and unidirectional planar, respectively). We show how the presence or absence of dislocations controls the structure of highly deformed thin smectic films. Each domain contains smectic layers curved in the shape of flattened hemicylinders to satisfy both anchoring conditions, together with grain boundaries whose size and shape are controlled by the presence of dislocation lines. A flat grain boundary normal to the interface connects neighboring hemicylinders, while a rotating grain boundary (RGB) is located near the axis of curvature of the cylinders. The RGB shape appears such that dislocation lines are concentrated at its summit close to the air interface. The smectic layers reach the polymer substrate via a transition region where the smectic layer orientation satisfies the planar anchoring conditions over the entire polymer substrate and whose thickness does not depend on that of the film. The strength of planar anchoring appears to be high, larger than 10(-2) mJ m(-2), compensating for the high energy cost of creating an additional 2D defect between a horizontal smectic layer and perpendicular ones of the transition region. This 2D defect may be melted, in order to avoid the creation of a transition region structure composed of a large number of dislocations. As a result, linear defect domains can be considered as arrays of oriented defects, straight dislocations of various Burger vectors, whose location is now known, and 2D nematic defects. The possibility of easy variation between the present structure with a moderate amount of dislocations and a structure with a large number of dislocations is also

  15. Morphogenesis of liquid crystal topological defects during the nematic-smectic A phase transition

    Science.gov (United States)

    Gim, Min-Jun; Beller, Daniel A.; Yoon, Dong Ki

    2017-05-01

    The liquid crystalline phases of matter each possess distinct types of defects that have drawn great interest in areas such as topology, self-assembly and material micropatterning. However, relatively little is known about how defects in one liquid crystalline phase arise from defects or deformations in another phase upon crossing a phase transition. Here, we directly examine defects in the in situ thermal phase transition from nematic to smectic A in hybrid-aligned liquid crystal droplets on water substrates, using experimental, theoretical and numerical analyses. The hybrid-aligned nematic droplet spontaneously generates boojum defects. During cooling, toric focal conic domains arise through a sequence of morphological transformations involving nematic stripes and locally aligned focal conic domains. This simple experiment reveals a surprisingly complex pathway by which very different types of defects may be related across the nematic-smectic A phase transition, and presents new possibilities for controlled deformation and patterning of liquid crystals.

  16. Smectic and columnar liquid crystals concepts and physical properties illustrated by experiments

    CERN Document Server

    Oswald, Patrick

    2005-01-01

    Liquid crystals allow us to perform experiments that provide insight into fundamental problems of modern physics, such as phase transitions, frustration, elasticity, hydrodynamics, defects, growth phenomena, and optics. Smectic and Columnar Liquid Crystals: Concepts and Physical Properties Illustrated by Experiments is a result of personal research and of the graduate lectures given by the authors at the École Normale Supérieure de Lyon and the University of Paris VII, respectively. The book examines lamellar (smectic) and columnar liquid crystals, which, in addition to orientational order, possess 1D, 2D or 3D positional order. This volume illustrates original physical concepts using methodically numerous experiments, theoretical developments, and diagrams. Topics include rheology and plasticity, ferroelectricity, analogies with superconductors, hexatic order and 2D-melting, equilibrium shapes, facetting, and the Mullins-Sekerka instability, as well as phase transitions in free films and membrane vibration...

  17. Physical properties of smectic C liquid crystal cells

    CERN Document Server

    Dunn, P E

    1998-01-01

    key material parameters. Polarisation reversal current is used to measure both the spontaneous polarisation and an effective FLC switching viscosity. Monochromatic extinction angle measurements under applied d.c. fields are used to determine the cone and layer tilt angles, whilst a comparison of d.c. and a.c. extinction angle characteristics provides an estimate of the dielectric biaxiality. An automated measurement technique is used to determine FLC response time characteristics, which are described by a dynamic continuum theory switching model. In addition to optical techniques, x-ray diffraction is used to probe directly the smectic layer structure of several materials aligned in the surface stabilised chevron geometry. The layer structures adopted with anti-parallel alignment are also examined as a function of surface pretilt. Uniformly tilted layer structures are found to occur in test cells subjected to mechanical damage, and high electric fields are shown to produce quasi-bookshelf layer structures. Al...

  18. One- and two-dimensional fluids properties of smectic, lamellar and columnar liquid crystals

    CERN Document Server

    Jakli, Antal

    2006-01-01

    Smectic and lamellar liquid crystals are three-dimensional layered structures in which each layer behaves as a two-dimensional fluid. Because of their reduced dimensionality they have unique physical properties and challenging theoretical descriptions, and are the subject of much current research. One- and Two-Dimensional Fluids: Properties of Smectic, Lamellar and Columnar Liquid Crystals offers a comprehensive review of these phases and their applications. The book details the basic structures and properties of one- and two-dimensional fluids and the nature of phase transitions. The later chapters consider the optical, magnetic, and electrical properties of special structures, including uniformly and non-uniformly aligned anisotropic films, lyotropic lamellar systems, helical and chiral structures, and organic anisotropic materials. Topics also include typical and defective features, magnetic susceptibility, and electrical conductivity. The book concludes with a review of current and potential applications ...

  19. Soft Micro- to Nanolithography Using Highly Periodic Smectic Liquid Crystal Defects

    Science.gov (United States)

    Jung, Hee-Tae; Kim, Yun Ho; Yoon, Dong Ki; Jeong, Hyeon Su

    2009-03-01

    Achieving perfect long-range order with soft building blocks at high speed and high resolution is one of the most exciting interdisciplinary research areas in current materials science and nano-biotechnology. Here, we have developed highly periodic patterns with sub-micrometer features over large-areas using toric focal conic domains (TFCDs) originated from smectic liquid crystal (LC). TFCDs are accomplished by precisely controlling the surface and interfacial properties of smectic LC. In order to apply the smectic liquid crystal defect arrays in lithography, the hexagonal arrays of domain patterns are used as molds for ultraviolet (UV) curable polymers, thereby providing LC defect stamps with high spatial resolution over large areas. Our method was further utilized to transfer patterns with sub-micrometer features from the polymer stamp surface to a secondary surface by microcontact printing (μ-CP). The patterning method based on LC defects has significant advantages over existing lithographic approaches: 1) the masters and stamps are easy to fabricate, 2) the masters and stamps provide long-range surface ordering over large-areas, 3) the periodic arrays are formed quickly in several seconds, and 4) the stamps can generate feature sizes on the micrometer and submicrometer length scales, and 5) the methodology offers the possibility of controlling the array geometry by altering the geometry of the confining channels.

  20. Drag of a Cottrell atmosphere by an edge dislocation in a smectic-A liquid crystal.

    Science.gov (United States)

    Oswald, P; Lejček, L

    2017-10-01

    In a recent letter (P. Oswald et al., EPL 103, 46004 (2013)), we have shown that a smectic-A phase hardens in compression normal to the layers when the liquid crystal is doped with gold nanoparticles. This is due to the formation of Cottrell clouds nearby the core of the edge dislocations and the appearance of an additional drag force that reduces their mobility. We theoretically calculate the shape of the Cottrell cloud and the associated drag force as a function of the climb velocity of the dislocations. The main result is that the drag force depends on velocity and vanishes when the temperature tends to the smectic-A-to-nematic transition temperature. The role of the diffusion anisotropy is also evaluated.

  1. Nanostructure of Edge Dislocations in a Smectic-C* Liquid Crystal.

    Science.gov (United States)

    Zhang, C; Grubb, A M; Seed, A J; Sampson, P; Jákli, A; Lavrentovich, O D

    2015-08-21

    We report on the first direct nanoscale imaging of elementary edge dislocations in a thermotropic smectic-C* liquid crystal with the Burgers vector equal to one smectic layer spacing d. We find two different types of dislocation profiles. In the dislocation of type A, the layers deformations lack mirror symmetry with respect to the plane perpendicular to the Burgers vector; the dislocation core size is on the order of d. In the dislocation of type S, the core is strongly anisotropic, extending along the Burgers vector over distances much larger (by a factor of 4) than d. The difference is attributed to a different orientation of the molecular tilt plane with respect to the dislocation's axis; the asymmetric layers distortions are observed when the molecular tilt plane is perpendicular to the axis and the split S core is observed when the molecules are tilted along the line.

  2. Polar Liquid Crystal Elastomers Cross Linked Far from Thermodynamic Phase Transitions: Dislocation Loops in Smectic Clusters

    Directory of Open Access Journals (Sweden)

    Yusril Yusuf

    2013-01-01

    Full Text Available Nematic networks with three different concentrations of polar and nonpolar mesogens and the same concentration of a novel cross-linking agent give rise to unusual liquid single crystal elastomers (LSCEs that are transparent monodomain nematic networks with smectic clusters. The largest spontaneous length change is observed in the sample with 70 mol% of the polar mesogen which also has the highest glass transition temperature and smectic clusters with a slowly increasing but nearly constant layer spacing on cooling from 90°C to 25°C. X-ray scattering intensity from smectic clusters with layer spacings that monotonically increase on cooling first increases to a maximum at T*~60∘C corresponding to clusters of about 30 layers. Below T∗, the scattering intensity decreases as the number of layers in a cluster decreases. To account for this surprising nonlinear behavior that correlates with nonlinear features of the networks’ macroscopic spontaneous shape change and birefringence, a model is proposed where dislocations form in the layers at T∗. Below T∗, more dislocations form to break down the layer structure. The possibility of dislocation formation at T∗ independent of mesogenic concentrations is attributed to a conformational change in the crosslinker which is present at the same concentration in the three LSCEs.

  3. Tuning the defect configurations in nematic and smectic liquid crystalline shells.

    Science.gov (United States)

    Liang, Hsin-Ling; Noh, JungHyun; Zentel, Rudolf; Rudquist, Per; Lagerwall, Jan P F

    2013-04-13

    Thin liquid crystalline shells surrounding and surrounded by aqueous phases can be conveniently produced using a nested capillary microfluidic system, as was first demonstrated by Fernandez-Nieves et al. in 2007. By choosing particular combinations of stabilizers in the internal and external phases, different types of alignment, uniform or hybrid, can be ensured within the shell. Here, we investigate shells in the nematic and smectic phases under varying boundary conditions, focusing in particular on textural transformations during phase transitions, on the interaction between topological defects in the director field and inclusions in the liquid crystal (LC), and on the possibility to relocate defects within the shell by rotating the shell in the gravitational field. We demonstrate that inclusions in a shell can seed defects that cannot form in a pristine shell, adding a further means of tuning the defect configuration, and that shells in which the internal aqueous phase is not density matched with the LC will gently rearrange the internal structure upon a rotation that changes the influence of gravity. Because the defects can act as anchor points for added linker molecules, allowing self-assembly of adjacent shells, the various arrangements of defects developing in these shells and the possibility of tuning the result by modifying boundary conditions, LC phase, thickness and diameter of the shell or applying external forces make this new LC configuration very attractive.

  4. Smectic ordering in nematic and smectic liquid-crystalline films probed by means of surface light scattering

    NARCIS (Netherlands)

    Böttger, A.; Frenkel, D.; Joosten, J.G.H.; Krooshof, G.

    1988-01-01

    We present the first results of experiments that measure the intensity of light scattered by capillary waves on the surface of free-standing liquid-crystalline thin films. The intensity of the scattered light provides information about the surface tension of the liquid-air interfaces and, more

  5. Bilayered smectic phase polymorphism in the dipolar Gay-Berne liquid crystal model.

    Science.gov (United States)

    Houssa, Mohammed; Rull, Luis F; Romero-Enrique, Jose M

    2009-04-21

    We present computer simulations of the Gay-Berne model with a strong terminal dipole. We report the existence of different stable antiferroelectric interdigitated bilayered phases in this model with diverse in-plane organization. The occurrence of these phases depends crucially on the value of the molecular elongation kappa. For kappa=3 we find an interdigitated bilayered smectic-A phase (absent when there is no dipole) and a bilayered smectic-T (or crystal) with positional in-plane tetragonal ordering, different from the hexatic observed in the absence of the molecular dipole. For kappa=4, bilayered smectic-A and in-plane hexatic-ordered smectic-B (or crystal) phases are observed.

  6. Flexible Bistable Smectic-A Liquid Crystal Device Using Photolithography and Photoinduced Phase Separation

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2012-01-01

    Full Text Available A flexible bistable smectic-A liquid crystal (SmA LC device using pixel-isolated mode was demonstrated, in which SmA LC molecules were isolated in pixels by vertical polymer wall and horizontal polymer layer. The above microstructure was achieved by using ultraviolet (UV photolithography and photoinduced phase separation. The polymer wall was fabricated by photolithography, and then the SmA LC was encapsulated in pixels between polymer wall through UV-induced phase separation, in which the polymer wall acts as supporting structure from mechanical pressure and maintains the cell gap from bending, and the polymer layer acts as adhesive for tight attachment of two substrates. The results demonstrated that all the intrinsic bistable properties of the SmA LC are preserved, and good electrooptical characteristics such as high contrast ratio and excellent stability of the bistable states were characterized. This kind of SmA bistable flexible display has high potential to be used as electronic paper, smart switchable reflective windows, and so forth.

  7. The x-ray surface forces apparatus: Structure of a thin smectic liquid crystal film under confinement

    Energy Technology Data Exchange (ETDEWEB)

    Idziak, S.H.J.; Kraiser, K.E.; Safinya, C.R.; Warriner, H.E.; Hill, R.S.; Ruths, M.; Liang, K.S.; Israelachvili, J.N. (Univ. of California, Santa Barbara, CA (United States))

    1994-06-24

    An x-ray surface forces apparatus for simultaneously measuring forces and structures of confined complex fluids under static and flow conditions is described. This apparatus, combined with an intense synchrotron x-ray source, allows investigation of molecular orientations within a thin liquid crystal film confined between two shearing mica surfaces 3900 angstroms apart. The layer-forming smectic liquid crystal 8CB (4-cyano-4[prime]-octylbiphenyl) adopted a series of distinct planar layer orientations, including the bulk flow-forbidden b orientation.

  8. Active microrheology of smectic membranes

    Science.gov (United States)

    Qi, Zhiyuan; Ferguson, Kyle; Sechrest, Yancey; Munsat, Tobin; Park, Cheol Soo; Glaser, Matthew A.; Maclennan, Joseph E.; Clark, Noel A.; Kuriabova, Tatiana; Powers, Thomas R.

    2017-02-01

    Thin fluid membranes embedded in a bulk fluid of different viscosity are of fundamental interest as experimental realizations of quasi-two-dimensional fluids and as models of biological membranes. We have probed the hydrodynamics of thin fluid membranes by active microrheology using small tracer particles to observe the highly anisotropic flow fields generated around a rigid oscillating post inserted into a freely suspended smectic liquid crystal film that is surrounded by air. In general, at distances more than a few Saffman lengths from the meniscus around the post, the measured velocities are larger than the flow computed by modeling a moving disklike inclusion of finite extent by superposing Levine-MacKintosh response functions for pointlike inclusions in a viscous membrane. The observed discrepancy is attributed to additional coupling of the film with the air below the film that is displaced directly by the shaft of the moving post.

  9. Anisotropic Dye Adsorption and Anhydrous Proton Conductivity in Smectic Liquid Crystal Networks: The Role of Cross-Link Density, Order, and Orientation.

    Science.gov (United States)

    Liang, Ting; van Kuringen, Huub P C; Mulder, Dirk J; Tan, Shuai; Wu, Yong; Borneman, Zandrie; Nijmeijer, Kitty; Schenning, Albertus P H J

    2017-10-11

    In this work, the decisive role of rigidity, orientation, and order in the smectic liquid crystalline network on the anisotropic proton and adsorbent properties is reported. The rigidity in the hydrogen-bonded polymer network has been altered by changing the cross-link density, the order by using different mesophases (smectic, nematic, and isotropic phases), whereas the orientation of the mesogens was controlled by alignment layers. Adding more cross-linkers improved the integrity of the polymer films. For the proton conduction, an optimum was found in the amount of cross-linker and the smectic organization results in the highest anhydrous proton conduction. The polymer films show anisotropic proton conductivity with a 54 times higher conductivity in the direction perpendicular to the molecular director. After a base treatment of the smectic liquid crystalline network, a nanoporous polymer film is obtained that also shows anisotropic adsorption of dye molecules and again straight smectic pores are favored over disordered pores in nematic and isotropic networks. The highly cross-linked films show size-selective adsorption of dyes. Low cross-linked materials do not show this difference due to swelling, which decreases the order and creates openings in the two-dimensional polymer layers. The latter is, however, beneficial for fast adsorption kinetics.

  10. Designing amphotropic smectic liquid crystals based on phosphonium salts for partial ordering of solutes as monitored by NMR spectroscopy.

    Science.gov (United States)

    Shahkhatuni, Astghik A; Ma, Kefeng; Weiss, Richard G

    2009-04-02

    The ordering parameters of selected solutes from NMR spectroscopic measurements have been assessed in the thermotropic and amphotropic smectic liquid-crystalline phases of a wide structural range of phosphonium salts with three equivalent long n-alkyl chains, one shorter chain, and various anions. The nature of the added liquids that convert the salts to amphotropic phasesalcohols and other small organic moleculesand their concentrations have been determined. These factors are correlated with the NMR-derived parameters in order to understand how the phases can be optimized to maximize information about the solutes. The various salts cover a range of liquid crystallinity from -40 to 100 degrees C. The phosphonium salts are easily aligned in the strong magnetic fields of the spectrometers. In several of the systems, a coexistence of isotropic and anisotropic phases is observed over a wide range of temperatures. The order parameters of the amphotropic liquid-crystalline phases vary from high to very low values, and some of the systems provide good spectral resolution for the solute molecules. Also, structural and orientational parameters of a model molecule, (13)C-enriched acetonitrile, have been calculated in various systems in order to evaluate more precisely the applicability of the host systems for determining solute structures by NMR. The results, in toto, indicate that several of the phosphonium salts are very promising as hosts to determine solute structures.

  11. Structural Rheology of the Smectic Phase

    Directory of Open Access Journals (Sweden)

    Shuji Fujii

    2014-07-01

    Full Text Available In this review article, we discuss the rheological properties of the thermotropic smectic liquid crystal 8CB with focal conic domains (FCDs from the viewpoint of structural rheology. It is known that the unbinding of the dislocation loops in the smectic phase drives the smectic-nematic transition. Here we discuss how the unbinding of the dislocation loops affects the evolution of the FCD size, linear and nonlinear rheological behaviors of the smectic phase. By studying the FCD formation from the perpendicularly oriented smectic layers, we also argue that dislocations play a key role in the structural development in layered systems. Furthermore, similarities in the rheological behavior between the FCDs in the smectic phase and the onion structures in the lyotropic lamellar phase suggest that these systems share a common physical origin for the elasticity.

  12. Microlenses of smectic flowers

    Science.gov (United States)

    Serra, Francesca; Gharbi, Mohamed-Amine; Liu, Iris B.; Luo, Yimin; Bade, Nathan D.; Kamien, Randall D.; Yang, Shu; Stebe, Kathleen J.

    2015-03-01

    The search for new and tunable optical components finds suitable candidates in liquid crystals, which have both reconfigurability and unique optical properties. Here we discuss smectic liquid crystals arranged in focal conic domains (FCDs), which can work as gradient-refractive index microlenses. We exploit this property to create an assembly of microlenses that resembles an insect compound eye. The system consists of a thin layer of smectics on a substrate patterned with microposts. The smectic film is pinned at the microposts, creating a curved interface that induces a hierarchical assembly of FCDs called the ''flower pattern'': each FCD resembles the petal of a flower around the micropost. The arrangement of FCDs, with the largest FCDs pinned at the top of the microposts and the smallest FCDs in the low-curvature regions far from the post, is mirrored into a hierarchy of focal lengths of the microlenses. This structure is reconfigurable by melting and cooling and it allows visualizing objects placed at different distances, hence it can be exploited for 3D image reconstruction. Similarly to the insect eyes, the flower pattern is sensitive to light polarization: the large FCDs, with the largest eccentricity, only work as microlenses for one direction of light polarization. We thank the MRSEC NSF Grant DMR11-20901.

  13. The Shape of Breasts Suspended in Liquid

    NARCIS (Netherlands)

    De Kleijn, S.C.; Rensen, W.H.J.

    2007-01-01

    Philips has designed an optical mammography machine. In this machine the breast is suspended into a cup in which the measurements take place. A special fluid is inserted into the cup to prevent the light from going around the breast instead of going through it but this fluid also weakens the signal.

  14. Induced Smectic X Phase Through Intermolecular Hydrogen-Bonded Liquid Crystals Formed Between Citric Acid and p- n-(Octyloxy)Benzoic Acid

    Science.gov (United States)

    Sundaram, S.; Subhasri, P.; Rajasekaran, T. R.; Jayaprakasam, R.; Senthil, T. S.; Vijayakumar, V. N.

    2017-08-01

    Hydrogen-bonded liquid crystal (HBLC) is synthesized from citric acid (CA) and 4-(octyloxy)benzoic acid (8OBA) with different mole ratios. Fourier transform infrared spectroscopy (FT-IR) confirms the presence of hydrogen bond between CA and 8OBA. Nuclear magnetic resonance (NMR) spectroscopic studies validate the intermolecular complementary, cyclic type of hydrogen bond, and molecular environment in the designed HBLC complex. Powder X-ray diffraction analysis reveals the monoclinic nature of liquid crystal complex in solid phase. Liquid crystal parameters such as phase transition temperature and enthalpy values for the corresponding mesogenic phases are investigated using a polarizing optical microscope (POM) and differential scanning calorimetry (DSC). It is observed that the change in chain length and steric hindrance while increasing the mole ratio in HBLC complex induces a new smectic X (Sm X) along with higher-order smectic G (Sm G) phases by quenching of smectic C (Sm C). From the experimental observations, induced Sm X phase has been identified as a finger print texture. Also, Sm G is a multi-colored mosaic texture in 1:1, 1:2, and 1:3 mol ratios. The optical tilt angle, thermal stability factor, and enhanced thermal span width of CA + 8OBA complex are discussed.

  15. Dynamic mechanism of the ferroelectric to antiferroelectric phase transition in chiral smectic liquid crystals

    OpenAIRE

    VIJ, JAGDISH; Fukuda, Atsuo; SONG, JANG-KUN

    2008-01-01

    PUBLISHED We report on the observation of V-shaped switching in a ferroelectric liquid crystal cell over a wide range of temperatures. Results of the optical transmittance in the visible region give us the helical pitch for various temperatures of the ferroelectric liquid crystalline compound used. We show that the helical pitch, in addition to the spontaneous polarization (PS) and thickness of the alignment layer of the cell, is an important factor in giving V-shaped switching. A longer o...

  16. Tailoring Anisotropic Interactions between Soft Nanospheres Using Dense Arrays of Smectic Liquid Crystal Edge Dislocations.

    Science.gov (United States)

    Coursault, Delphine; Blach, Jean-Francois; Grand, Johan; Coati, Alessandro; Vlad, Alina; Zappone, Bruno; Babonneau, David; Lévi, Georges; Félidj, Nordin; Donnio, Bertrand; Gallani, Jean-Louis; Alba, Michel; Garreau, Yves; Borensztein, Yves; Goldmann, Michel; Lacaze, Emmanuelle

    2015-12-22

    We investigated composite films of gold nanoparticles (NPs)/liquid crystal (LC) defects as a model system to understand the key parameters, which allow for an accurate control of NP anisotropic self-assemblies using soft templates. We combined spectrophotometry, Raman spectroscopy, and grazing incidence small-angle X-ray scattering with calculations of dipole coupling models and soft sphere interactions. We demonstrate that dense arrays of elementary edge dislocations can strongly localize small NPs along the defect cores, resulting in formation of parallel chains of NPs. Furthermore, we show that within the dislocation cores the inter-NP distances can be tuned. This phenomenon appears to be driven by the competition between "soft (nano)sphere" attraction and LC-induced repulsion. We evidence two extreme regimes controlled by the solvent evaporation: (i) when the solvent evaporates abruptly, the spacing between neighboring NPs in the chains is dominated by van der Waals interactions between interdigitated capping ligands, leading to chains of close-packed NPs; (ii) when the solvent evaporates slowly, strong interdigitation between the is avoided, leading to a dominating LC-induced repulsion between NPs associated with the replacement of disordered cores by NPs. The templating of NPs by topological defects, beyond the technological inquiries, may enable creation, investigation, and manipulation of unique collective features for a wide range of nanomaterials.

  17. Thermal Conductivity Measurement of Liquids by Using a Suspended Microheater

    Science.gov (United States)

    Oh, Dong-Wook

    2017-10-01

    In this paper, the traditional 3ω method is modified in order to measure the thermal conductivity of a droplet of liquid. The 3ω sensor is microfabricated using bulk silicon etching on a silicon wafer to form a microheater on a suspended bridge structure. The Si substrate of over 400 μ m thickness beneath the microheater is etched away so that the sample liquid can fill the gap created between the heater and the bottom boundary of the sensor. The frequency of the sinusoidal heating pulses that are generated from the heater is controlled such that the thermal penetration depth is much smaller than the thickness of the liquid layer. The temperature oscillation of the sample fluid is measured at the thin-film heater to calculate the thermal conductivity of the surrounding fluid. The thermal conductivity and measured values of the de-ionized water and ethanol show a good agreement with the theoretical values at room temperature.

  18. The Ages in a Self-Suspended Nanoparticle Liquid

    KAUST Repository

    Agarwal, Praveen

    2010-01-13

    Telomers ionically tethered to nanometer-sized particles yield self-suspended, nanoparticle-Iaden liquids with unusual dynamical features. By subjecting these suspensions to controlled, modest shear strains, we find that their flow behaviors observed using experiments performed on time scales of tens of seconds can be projected to obtain maps of their dynamical response on geological time scales. That such extraordinarily slow dynamic processes can be uncovered from real-time measurements by simply stretching a system provides a simple but powerful tool for interrogating extremely slow motions in other jammed physical states. © 2010 American Chemical Society.

  19. Oscillation of a diamagnetic liquid bubble suspended by magnetic force

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, R. E-mail: yamane@kokushikan.ac.jp; Tomita, S.; Mai, J.; Park, M.K.; Oshima, S

    2002-11-01

    The levitation of the diamagnetic liquid droplet with the strong magnetic field is experimentally simulated, using the magnetic fluid as the surrounding fluid in place of air or gas, and the water bubble is levitated with the conventional permanent magnet. When the stepwise magnetic field is superposed, the suspended bubble behaves as a typical step response with the overshoot and viscous damping. The effects of the volume of the bubble, the strength of the magnetic field and the concentration of the magnetic fluid are investigated.

  20. Surface induced smectic order in ionic liquids - an X-ray reflectivity study of [C22C1im]+[NTf2].

    Science.gov (United States)

    Mars, Julian; Hou, Binyang; Weiss, Henning; Li, Hailong; Konovalov, Oleg; Festersen, Sven; Murphy, Bridget M; Rütt, Uta; Bier, Markus; Mezger, Markus

    2017-10-11

    Surface induced smectic order was found for the ionic liquid 1-methyl-3-docosylimidazolium bis(trifluoromethlysulfonyl)imide by X-ray reflectivity and grazing incidence scattering experiments. Near the free liquid surface, an ordered structure of alternating layers composed of polar and non-polar moieties is observed. This leads to an oscillatory interfacial profile perpendicular to the liquid surface with a periodicity of 3.7 nm. Small angle X-ray scattering and polarized light microscopy measurements suggest that the observed surface structure is related to fluctuations into a metastable liquid crystalline SmA2 phase that was found by supercooling the bulk liquid. The observed surface ordering persists up to 157 °C, i.e. more than 88 K above the bulk melting temperature of 68.1 °C. Close to the bulk melting point, we find a thickness of the ordered layer of L = 30 nm. The dependency of L(τ) = Λ ln(τ/τ1) vs. reduced temperature τ follows a logarithmic growth law. In agreement with theory, the pre-factor Λ is governed by the correlation length of the isotropic bulk phase.

  1. 40 CFR 227.32 - Liquid, suspended particulate, and solid phases of a material.

    Science.gov (United States)

    2010-07-01

    ... MATERIALS Definitions § 227.32 Liquid, suspended particulate, and solid phases of a material. (a) For the... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Liquid, suspended particulate, and solid phases of a material. 227.32 Section 227.32 Protection of Environment ENVIRONMENTAL PROTECTION...

  2. Isotropic to smectic A phase transitions in a porous matrix a case of multiporous phase coexistence

    CERN Document Server

    Bellini, T; Link, D R

    2003-01-01

    The one-dimensional smectic ordering of the liquid crystal 10CB incorporated in the pores of a silica aerogel has been investigated via x-ray scattering. Although the smectic order is made short-ranged by the aerogel host and the amplitude of the associated Bragg-like peak grows continuously with decreasing temperature, part of the first-order character of the 10CB's direct isotropic-smectic phase transition is retained in the discontinuous temperature dependence of the smectic correlation length. This behaviour contrasts with that of materials where the smectic phase develops from a locally orientationally ordered nematic and can be interpreted as a nucleation-type process.

  3. The smectic order of wrinkles

    Science.gov (United States)

    Aharoni, Hillel; Todorova, Desislava V.; Albarrán, Octavio; Goehring, Lucas; Kamien, Randall D.; Katifori, Eleni

    2017-07-01

    A thin elastic sheet lying on a soft substrate develops wrinkled patterns when subject to an external forcing or as a result of geometric incompatibility. Thin sheet elasticity and substrate response equip such wrinkles with a global preferred wrinkle spacing length and with resistance to wrinkle curvature. These features are responsible for the liquid crystalline smectic-like behaviour of such systems at intermediate length scales. This insight allows better understanding of the wrinkling patterns seen in such systems, with which we explain pattern breaking into domains, the properties of domain walls and wrinkle undulation. We compare our predictions with numerical simulations and with experimental observations.

  4. The effect of confinement on the stability of field induced states and on supercooling in antiferro-ferroelectric phase transitions in chiral smectic liquid crystals

    OpenAIRE

    VIJ, JAGDISH

    2009-01-01

    PUBLISHED We investigate both the supercooling and the hysteresis phenomena of the phase transitions between the smectic C* and the smectic C *Aphases driven by temperature and electric field, respectively. These two phenomena show similar characteristics for the dependence of transmittance on both the cell thickness and the applied field. The mechanisms for large supercooling and large hysteresis in thin cells are shown to correspond to the suppression of the propagation of solitary wave ...

  5. Supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Koch, Michel H J; Fahr, Alfred

    2009-01-01

    Cholesteryl nonanoate (CN), myristate (CM), palmitate (CP) and oleate (CO) alone or in combination were evaluated as matrix lipids for the preparation of supercooled smectic nanoparticles with a high stability against recrystallization during storage. The phase behavior of the cholesterol esters......, laser diffraction combined with polarizing intensity differential scattering, DSC and SAXS. The morphology of selected formulations was studied by freeze-fracture electron microscopy. All smectic nanoparticles with a mixed cholesterol ester matrix were stable against recrystallization when stored...... at room temperature. Nanoparticles with a pure CN and mixed CM/CN matrix with a high fraction of CN (60% of the whole lipid matrix) could even be stored at 4 degrees C for at least 18 months without any recrystallization. As smectic nanoparticles are studied especially with regard to parenteral...

  6. Simple Landau model of the Smectic-C{sub {alpha}}{sup *}-Smectic-C{sup *} phase transition in binary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Prabir K., E-mail: pkmukherje@yahoo.co.i [Department of Physics, Presidency University, 86/1 College Street, Kolkata 700 073 (India)

    2011-05-01

    Simple Landau-type free energy function is presented to describe the Smectic-C{sub {alpha}}{sup *}-Smectic-C{sup *} transition in a liquid crystal mixture. The problem of the first or second order transition is explored by means of the variation of the concentration. The influence of the concentration on this transition is discussed by varying the coupling between the concentration variable and the order parameter. Within this model the Smectic-C{sub {alpha}}{sup *}-Smectic-C{sup *} transition is found to be always first order transition that ends at a critical point. The presented analysis is in good agreement with the experimental results.

  7. Gradual phase transition between the smectic- C* and smectic- CA* phases and the thresholdless antiferroelectricity

    OpenAIRE

    VIJ, JAGDISH; SONG, JANG-KUN; Fukuda, Atsuo

    2008-01-01

    PUBLISHED We have constructed the phase diagrams for a binary-mixture system of antiferroelectric and ferroelectric liquid-crystalline materials in both thick and thin cells. In the phase diagrams the boundary between the smectic-C* and smectic-CA * phases runs almost parallel to the temperature axis below from ca. 70 ?C down to at least ?25 ?C. The SmC*-SmCA * phase transition for a thin cell shows a large supercooling, and a gradual transition occurs near the boundary. ...

  8. Surface-induced discrete smectic order in the isotropic phase of 12 CB in cylindrical pores

    Science.gov (United States)

    Iannacchione, Germano S.; Mang, Joseph T.; Kumar, Satyendra; Finotello, Daniele

    1994-11-01

    Through specific-heat and x-ray scattering studies, we show the existence of surface-induced discrete smectic order in the isotropic phase for dodecylcyanobiphenyl (12CB) confined to Anopore membranes. A quantized smectic layer growth is promoted by the pore surface when treated with an aliphatic acid of varying chain length. No surface-induced smectic order develops in untreated or lecithin treated pores nor in liquid crystals that possess a nematic phase.

  9. Realization of hydrodynamic experiments on quasi-2D liquid crystal films in microgravity

    Science.gov (United States)

    Clark, Noel A.; Eremin, Alexey; Glaser, Matthew A.; Hall, Nancy; Harth, Kirsten; Klopp, Christoph; Maclennan, Joseph E.; Park, Cheol S.; Stannarius, Ralf; Tin, Padetha; Thurmes, William N.; Trittel, Torsten

    2017-08-01

    Freely suspended films of smectic liquid crystals are unique examples of quasi two-dimensional fluids. Mechanically stable and with quantized thickness of the order of only a few molecular layers, smectic films are ideal systems for studying fundamental fluid physics, such as collective molecular ordering, defect and fluctuation phenomena, hydrodynamics, and nonequilibrium behavior in two dimensions (2D), including serving as models of complex biological membranes. Smectic films can be drawn across openings in planar supports resulting in thin, meniscus-bounded membranes, and can also be prepared as bubbles, either supported on an inflation tube or floating freely. The quantized layering renders smectic films uniquely useful in 2D fluid physics. The OASIS team has pursued a variety of ground-based and microgravity applications of thin liquid crystal films to fluid structure and hydrodynamic problems in 2D and quasi-2D systems. Parabolic flights and sounding rocket experiments were carried out in order to explore the shape evolution of free floating smectic bubbles, and to probe Marangoni effects in flat films. The dynamics of emulsions of smectic islands (thicker regions on thin background films) and of microdroplet inclusions in spherical films, as well as thermocapillary effects, were studied over extended periods within the OASIS (Observation and Analysis of Smectic Islands in Space) project on the International Space Station. We summarize the technical details of the OASIS hardware and give preliminary examples of key observations.

  10. Ferromagnetic transition in a one-dimensional spin-orbit-coupled metal and its mapping to a critical point in smectic liquid crystals

    Science.gov (United States)

    Kozii, Vladyslav; Ruhman, Jonathan; Fu, Liang; Radzihovsky, Leo

    2017-09-01

    We study the quantum phase transition between a paramagnetic and ferromagnetic metal in the presence of Rashba spin-orbit coupling in one dimension. Using bosonization, we analyze the transition by means of renormalization group, controlled by an ɛ expansion around the upper critical dimension of two. We show that the presence of Rashba spin-orbit coupling allows for a new nonlinear term in the bosonized action, which generically leads to a fluctuation driven first-order transition. We further demonstrate that the Euclidean action of this system maps onto a classical smectic-A-C phase transition in a magnetic field in two dimensions. We show that the smectic transition is second order and is controlled by a new critical point.

  11. Experimental study of the viscosity of suspensions: effect of solid fraction, particle size and suspending liquid

    NARCIS (Netherlands)

    Konijn, B.J.; Sanderink, O.B.J.; Kruyt, Nicolaas P.

    2014-01-01

    The behaviour of nearly neutrally-buoyant suspensions has been studied experimentally, using a concentric-cylinder rheometer. The effect on the suspension viscosity of: (i) solid fraction, (ii) diameter of the solid, spherical particles, (iii) viscosity of the suspending liquid, and (iv) shear rate

  12. Templated Native Silk Smectic Gels

    Science.gov (United States)

    Jin, Hyoung-Joon (Inventor); Park, Jae-Hyung (Inventor); Valluzzi, Regina (Inventor)

    2016-01-01

    One aspect of the present invention relates to a method of preparing a fibrous protein smectic hydrogel by way of a solvent templating process, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; and collecting the resulting fibrous protein smectic hydrogel and allowing it to dry. Another aspect of the present invention relates to a method of obtaining predominantly one enantiomer from a racemic mixture, comprising the steps of pouring an aqueous fibrous protein solution into a container comprising a solvent that is not miscible with water; sealing the container and allowing it to age at about room temperature; allowing the enantiomers of racemic mixture to diffuse selectively into the smectic hydrogel in solution; removing the smectic hydrogel from the solution; rinsing predominantly one enantiomer from the surface of the smectic hydrogel; and extracting predominantly one enantiomer from the interior of the smectic hydrogel. The present invention also relates to a smectic hydrogel prepared according to an aforementioned method.

  13. Highly Sensitive Measurement of Liquid Density in Air Using Suspended Microcapillary Resonators

    Directory of Open Access Journals (Sweden)

    Oscar Malvar

    2015-03-01

    Full Text Available We report the use of commercially available glass microcapillaries as micromechanical resonators for real-time monitoring of the mass density of a liquid that flows through the capillary. The vibration of a suspended region of the microcapillary is optically detected by measuring the forward scattering of a laser beam. The resonance frequency of the liquid filled microcapillary is measured for liquid binary mixtures of ethanol in water, glycerol in water and Triton in ethanol. The method achieves a detection limit in an air environment of 50 µg/mL that is only five times higher than that obtained with state-of-the-art suspended microchannel resonators encapsulated in vacuum. The method opens the door to novel advances for miniaturized total analysis systems based on microcapillaries with the add-on of mechanical transduction for sensing the rheological properties of the analyzed fluids without the need for vacuum encapsulation of the resonators.

  14. Thermodynamic stability of a smectic phase in a system of hard rods

    Science.gov (United States)

    Frenkel, D.; Lekkerkerker, H. N. W.; Stroobants, A.

    1988-04-01

    One of the most remarkable phenomena exhibited by colloidal suspensions of monodisperse rod-like particles is the spontaneous formation of smectic liquid crystals1 5. In these smectic phases, the particles order in periodic layers; on average, the axes of the rods are perpendicular to the layers. Smectics are distinct from crystals in that there is no long-range positional order within the layers. Because the spacing of the smectic layers is of the order of optical wavelengths, white light is separated into colours when scattered, giving rise to beautiful iridescence as in the colour photographs of ref. 2. As early as 1949, Onsager6 showed that nematic ordering may arise from hard-core repulsions between anisometric particles. However, it appears to have been generally accepted in the literature that smectic liquid crystalline ordering demands that attractive forces also operate7. There is nevertheless experimental evidence that smectic ordering does occur in colloidal systems where the particles interact predominantly through repulsive electrostatic interactions. This observation raises the fundamental question of whether smectic ordering can occur in a system of particles with purely repulsive interactions. Inspired by the seminal work of Alder and Wainwright8 on the freezing of a system of hard spheres, we have explored the possibility that smectic ordering occurs in a fluid of hard rod-like particles. Earlier computer simulations on hard parallel spherocylinders9,10 (cylinders with length L and diameter D, capped at each end with hemispheres of the same diameter) indicated that, in this somewhat artificial system, smectic order was indeed possible. Here we present numerical evidence that hard spherocylinders with both translational and orientational freedom can form a thermodynamically stable smectic phase.

  15. Frustration in smectic layers of polar Gay-Berne systems.

    Science.gov (United States)

    Józefowicz, W; Longa, L

    2007-07-01

    The main focus of the present paper is studying dipolar frustration within smectic- A(d) layers as induced by dipole-dipole interactions. Our reference point is the Gay-Berne system with kappa=4, kappa'=5, mu=2 and nu=1, which in the phase diagram shows a stable "island" of smectic- A phase with a short-range hexagonal order within each layer [Phys. Rev. E 57, 6685 (1998)]. We carry out isothermal-isobaric Monte Carlo simulations for a dipolar version of this model, where the Gay-Berne interaction is supplemented by interaction between longitudinal dipole moments. For a fixed off-center position of the dipoles we increase value of the dipole moment and follow evolution of the liquid-crystalline part of the phase diagram focusing on changes of the nematic-smectic- A phase boundaries and on structural response of the smectic- A layers. For weak dipoles only the classical smectic- A phase is stabilized, which then transforms into smectic- A(d) with layers being formed by two ferroelectrically polarized sublayers of opposite polarization. Average positions of dipoles that contribute to the polarization of a sublayer are located in a common plane, referred to as a dipolar plane. For not too strong dipole-dipole interactions increasing magnitude of the dipole moment causes stabilization of nematic at the expense of smectic- A(d). Under the same conditions the layer spacing increases and the distance between the dipolar planes within layers decreases. Each smectic sublayer is characterized by a short-range hexagonal order of the molecular centers of mass. With the dipole moment exceeding the threshold value, the polarization planes that built up the layers start to merge, which sets in the dipolar frustration. This, in turn, forces the system to develop a competition between frustrated hexagonal- and frustration-free tetragonal local order within each layer. When the local hexagonal order is transformed into the tetragonal one the stability range of smectic-A(d) increases

  16. Deformation and burst of a liquid droplet freely suspended in a linear shear field

    Science.gov (United States)

    Barthes-Biesel, D.; Acrivos, A.

    1973-01-01

    A theoretical method is presented for predicting the deformation and the conditions for breakup of a liquid droplet freely suspended in a general linear shear field. This is achieved by expanding the solution to the creeping-flow equations in powers of the deformation parameter epsilon and using linear stability theory to determine the onset of bursting. When compared with numerical solutions and with the available experimental data, the theoretical results are generally found to be of acceptable accuracy although, in some cases, the agreement is only qualitative.

  17. From viscous to elastic sheets: Dynamics of smectic freely floating films

    Science.gov (United States)

    Stannarius, Ralf; Harth, Kirsten; May, Kathrin; Trittel, Torsten

    The dynamics of droplets and bubbles, particularly on microscopic scales, are of considerable importance in biological, environmental, and technical contexts. Soap bubbles, vesicles and components of biological cells are well known examples where the dynamic behavior is significantly influenced by the properties of thin membranes enclosed by fluids. Two-dimensional membrane motions couple to 3D shape transformations. Smectic liquid crystal mesogens form phases with internal molecular layer order. Free-standing films are easily prepared from this class of materials. They represent simple model systems for membrane dynamics and pattern formation in a quasi two-dimensional fluid. These films are usually spanned over a frame, and they can be inflated to bubbles on a support. Recently, closed microscopic shells of liquid-crystalline materials suspended in an outer fluid without contact to a solid support have been introduced and studied. With a special technique, we prepare millimetre to centimetre sized smectic bubbles in air (similar to soap bubbles). Their distinct feature is the fact that any change of surface area is coupled to a restructuring of the layers in the membrane. High-speed cameras are used to observe the shape transformations of freely floating bubbles from a distorted initial shape to a sphere. Bursting dynamics are recorded and compared to models. Most strikingly, an unpreceded cross-over from inviscid to viscous and elastic behaviour with increasing thickness of the membrane is found: Whereas thin bubbles behave almost like inviscid fluids, the relaxation dynamics slows down considerably for larger film thicknesses. Surface wrinkling and formation of extrusions are observed. We will present a characterization and an expalantion for the above phenomena.

  18. Viscoelastic modes in chiral liquid crystals

    Indian Academy of Sciences (India)

    amit@fs.rri.local.net (Amit Kumar Agarwal)

    our studies on the viscoelastic modes of some chiral liquid crystals using dynamic light scattering. We discuss viscoelastic modes corresponding to the C director fluctuations in the chiral smectic C phase and the behaviour of the Goldstone-mode near the chiral smectic C–smectic A phase transition. In cholesteric liquid ...

  19. Supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Westesen, K; Drechsler, M

    2004-01-01

    The possibility of preparing nanoparticles in the supercooled thermotropic liquid crystalline state from cholesterol esters with saturated acyl chains as well as the incorporation of model drugs into the dispersions was investigated using cholesteryl myristate (CM) as a model cholesterol ester....

  20. Tyrosine-Based Ionic Liquid Crystals: Switching from a Smectic A to a Columnar Mesophase by Exchange of the Spherical Counterion.

    Science.gov (United States)

    Neidhardt, Manuel M; Wolfrum, Manpreet; Beardsworth, Stuart; Wöhrle, Tobias; Frey, Wolfgang; Baro, Angelika; Stubenrauch, Cosima; Giesselmann, Frank; Laschat, Sabine

    2016-11-07

    Synthetic strategies were developed to prepare l-tyrosine-based ionic liquid crystals with structural variations at the carboxylic and phenolic OH groups as well as the amino functionality. Salt metathesis additionally led to counterion variation. The liquid-crystalline properties were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS, SAXS). The symmetrical ILC chlorides bearing the same alkyl chain at both the ester and ether but either an acyclic or cyclic guanidinium group displayed enantiotropic SmA2 mesophases with phase widths of 31-88 K irrespective of the head group. It was particularly the replacement of chloride in the acyclic guanidinium ILC by hexafluorophosphate that induced a phase change from SmA2 to Colr . This phase change was attributed to a higher curvature of the interface due to the larger anion, which increased the effective head group cross-sectional area of the amphiphilic ILC. The unsymmetrical acyclic guanidinium chlorides, bearing a constant C14 ester and variable alkyl chains on the phenolic position, formed enantiotropic SmA2 phases. The derivative with the largest difference in chain lengths, however, displayed a Colr phase, resulting from discoid aggregates of the cone-shaped guanidinium chloride. The results are discussed in terms of the packing parameters, which indicate that the phase behaviour of the thermotropic tyrosine-based ILCs shows analogies to those of lyotropic liquid crystals. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Interactions between colloidal inclusions in two-dimensional smectic-C* films.

    Science.gov (United States)

    Cluzeau, P; Poulin, P; Joly, G; Nguyen, H T

    2001-03-01

    We report an experimental study of colloidal inclusions in free-standing films of smectic-C* liquid crystal. The inclusions are cholesteric droplets that form above the bulk smectic-C*-7cholesteric transition temperature. Each droplet confined in a two-dimensional (2D) system, is accompanied by a topological defect. The distortions of the in-plane orientational order of the smectic-C* film induce elastic interactions between the droplets. As in 3D water nematic emulsions, a short-range repulsion and a long-range dipolar attraction govern the stability of the inclusions and lead to their organization in chainlike structures. Our results are in agreement with recent theoretical predictions.

  2. Liquid-induced damping of mechanical feedback effects in single electron tunneling through a suspended carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, D. R.; Stiller, P. L.; Strunk, Ch.; Hüttel, A. K., E-mail: andreas.huettel@ur.de [Institute for Experimental and Applied Physics, University of Regensburg, Universitätsstr. 31, 93053 Regensburg (Germany)

    2015-09-21

    In single electron tunneling through clean, suspended carbon nanotube devices at low temperature, distinct switching phenomena have regularly been observed. These can be explained via strong interaction of single electron tunneling and vibrational motion of the nanotube. We present measurements on a highly stable nanotube device, subsequently recorded in the vacuum chamber of a dilution refrigerator and immersed in the {sup 3}He/ {sup 4}He mixture of a second dilution refrigerator. The switching phenomena are absent when the sample is kept in the viscous liquid, additionally supporting the interpretation of dc-driven vibration. Transport measurements in liquid helium can thus be used for finite bias spectroscopy where otherwise the mechanical effects would dominate the current.

  3. Numerical study of light-induced phase behavior of smectic solids

    Science.gov (United States)

    Chung, Hayoung; Park, Jaesung; Cho, Maenghyo

    2016-10-01

    By the chemical cross-linking of rigid molecules, liquid crystal polymer (LCP) has been envisaged as a novel heterogeneous material due to the fact that various optical and geometric states of the liquid crystalline (LC) phases are projected onto the polymeric constituents. The phase behavior, which refers to the macroscopic shape change of LCP under thermotropic phase change, is a compelling example of such optical-mechanical coupling. In this study, the photomechanical behavior, which broadly refers to the thermal- or light-induced actuation of smectic solids, is investigated using three-dimensional nonlinear finite element analysis (FEA). First, the various phases of LC are considered as well as their relation to polymeric conformation defined by the strain energy of the smectic polymer; a comprehensive constitutive equation that bridges the strong, optomechanical coupling is then derived. Such photomechanical coupling is incorporated in the FEA considering geometric nonlinearity, which is vital to understanding the large-scale light-induced bending behavior of the smectic solid.To demonstrate the simulation capability of the present model, numerous examples of photomechanical deformations are investigated parametrically, either by changing the operating conditions such as stimuli (postsynthesis) or the intrinsic properties (presynthesis). When compared to nematic solids, distinguished behaviors due to smectic substances are found herein and discussed through experiments. The quasisoftness that bidirectionally couples microscopic variables to mechanical behavior is also explained, while considering the effect of nonlinearity. In addition to providing a comprehensive measure that could deepen the knowledge of photomechanical coupling, the use of the proposed finite element framework offers an insight into the design of light-responsive actuating systems made of smectic solids.

  4. Insights on some chiral smectic phases

    Indian Academy of Sciences (India)

    journal of. August 2003 physics pp. 285–295. Insights on some chiral smectic phases. B PANSU. Laboratoire de Physique des Solides, Bt 510, UMR 8502, Universit ..... volve complex organizations of small SmCA grains, small meaning that the width of each grain is ... The colours of the platelets are due to low birefringence.

  5. Calculation of the Dielectric Constant as a Function of Temperature Close to the Smectic A-Smectic B Transition in B5 Using the Mean Field Model

    Directory of Open Access Journals (Sweden)

    Hamit Yurtseven

    2012-01-01

    Full Text Available The temperature dependence of the static dielectric constant ( is calculated close to the smectic A-smectic B ( transition ( = 71.3°C for the liquid crystal compound B5. By expanding the free energy in terms of the order parameter in the mean field theory, the expression for the dielectric susceptibility (dielectric constant is derived and is fitted to the experimental data for which was obtained at the field strengths of 0 and 67 kV/cm from literature. Coefficients in the free energy expansion are determined from our fit for the transition of B5. Our results show that the observed behaviour of the dielectric constant close to the transition in B5 can be described satisfactorily by our mean field model.

  6. Structures and orientational transitions in thin films of tilted hexatic smectics

    OpenAIRE

    Dolganov, P. V.; Belov, K. I.; Dolganov, V. K.; Demikhov, E. I.; Bolotin, B. M.; Kats, E.I.

    2005-01-01

    We present detailed systematic studies of structural transformations in thin liquid crystal films with the smectic-C to hexatic phase transition. For the first time all possible structures reported in the literature are observed for one material (5 O.6) at the variation of temperature and thickness. In unusual modulated structures the equilibrium period of stripes is twice with respect to the domain size. We interpret these patterns in the frame work of phenomenological Landau type theory, as...

  7. In vitro release studies on drugs suspended in non-polar media I. Release of sodium chloride from suspensions in liquid paraffin

    NARCIS (Netherlands)

    Crommelin, D.J.A.; Blaey, C.J. de

    The release of a readily water-soluble substance (sodium chloride) from a liquid paraffin phase to an underlying water phase was investigated as a function of particle size (10–50 μm) and concentration (up to 10% m/m). Transport of the suspended particles to the interface by sedimentation was the

  8. In vitro release studies on drugs suspended in non-polar media II. The release of paracetamol and chloramphenicol from suspensions in liquid paraffin

    NARCIS (Netherlands)

    Crommelin, D.J.A.; Blaey, C.J. de

    The release of paracetamol and chloramphenicol (water solubility 13 and 3.6 mg · g−1, respectively), suspended in liquid paraffin, to an underlying aqueous layer was investigated as a function of particle size (10–60 μm), concentration (0.5–6% m/m) and the presence of additives (DOSS-Na:

  9. DETERMINATION OF HEAT TRANSFER COEFFICIENTS FOR FRENCH PLASTIC SEMEN STRAW SUSPENDED IN STATIC NITROGEN VAPOR OVER LIQUID NITROGEN.

    Science.gov (United States)

    Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N

    2015-01-01

    The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

  10. Measurement of Density, Sound Velocity, Surface Tension, and Viscosity of Freely Suspended Supercooled Liquids

    Science.gov (United States)

    Trinh, E. H.

    1995-01-01

    Non-contact methods have been implemented in conjunction with levitation techniques to carry out the measurement of the macroscopic properties of liquids significantly cooled below their nominal melting point. Free suspension of the sample and remote methods allow the deep excursion into the metastable liquid state and the determination of its thermophysical properties. We used this approach to investigate common substances such as water, o-terphenyl, succinonitrile, as well as higher temperature melts such as molten indium, aluminum and other metals. Although these techniques have thus far involved ultrasonic, electromagnetic, and more recently electrostatic levitation, we restrict our attention to ultrasonic methods in this paper. The resulting magnitude of maximum thermal supercooling achieved have ranged between 10 and 15% of the absolute temperature of the melting point for the materials mentioned above. The physical properties measurement methods have been mostly novel approaches, and the typical accuracy achieved have not yet matched their standard equivalent techniques involving contained samples and invasive probing. They are currently being refined, however, as the levitation techniques become more widespread, and as we gain a better understanding of the physics of levitated liquid samples.

  11. Double smectic self-assembly in block copolypeptide complexes

    KAUST Repository

    Haataja, Johannes S.

    2012-11-12

    We show double smectic-like self-assemblies in the solid state involving alternating layers of different polypeptide α-helices. We employed rod-coil poly(γ-benzyl l-glutamate)-block-poly(l-lysine) (PBLG-b-PLL) as the polymeric scaffold, where the PLL amino residues were ionically complexed to di-n-butyl phosphate (diC4P), di(2-ethylhexyl) phosphate (diC2/6P), di(2-octyldodecyl) phosphate (diC8/12P), or di-n-dodecyl phosphate (diC12P), forming PBLG-b-PLL(diC4P), PBLG-b-PLL(diC2/6P), PBLG-b-PLL(diC8/12P), and PBLG-b-PLL(diC12P) complexes, respectively. The complexes contain PBLG α-helices of fixed diameter and PLL-surfactant complexes adopting either α-helices of tunable diameters or β-sheets. For PBLG-b-PLL(diC4P), that is, using a surfactant with short n-butyl tails, both blocks were α-helical, of roughly equal diameter and thus with minor packing frustrations, leading to alternating PBLG and PLL(diC4P) smectic layers of approximately perpendicular alignment of both types of α-helices. Surfactants with longer and branched alkyl tails lead to an increased diameter of the PLL-surfactant α-helices. Smectic alternating PBLG and PLL(diC2/6P) layers involve larger packing frustration, which leads to poor overall order and suggests an arrangement of tilted PBLG α-helices. In PBLG-b-PLL(diC8/12P), the PLL(diC8/12P) α-helices are even larger and the overall structure is poor. Using a surfactant with two linear n-dodecyl tails leads to well-ordered β-sheet domains of PLL(diC12P), consisting of alternating PLL and alkyl chain layers. This dominates the whole assembly, and at the block copolypeptide length scale, the PBLG α-helices do not show internal order and have poor organization. Packing frustration becomes an important aspect to design block copolypeptide assemblies, even if frustration could be relieved by conformational imperfections. The results suggest pathways to control hierarchical liquid-crystalline assemblies by competing interactions and by

  12. Fundamental measure theory for smectic phases: scaling behavior and higher order terms.

    Science.gov (United States)

    Wittmann, René; Marechal, Matthieu; Mecke, Klaus

    2014-08-14

    The recent extension of Rosenfeld's fundamental measure theory to anisotropic hard particles predicts nematic order of rod-like particles. Our analytic study of different aligned shapes provides new insights into the structure of this density functional, which is basically founded on experience with hard spheres. We combine scaling arguments with dimensional crossover and motivate a modified expression, which enables an appropriate description of smectic layering. We calculate the nematic-smectic-A transition of monodisperse hard spherocylinders with and without orientational degrees of freedom and present the equation of state and phase diagram including these two liquid crystalline phases in good agreement with simulations. We also find improved results related to the isotropic-nematic interface. We discuss the quality of empirical corrections and the convergence towards an exact second virial coefficient, including higher order terms.

  13. Electromechanical memory effect in a ferroelectric nanoparticle-suspended liquid crystal

    Science.gov (United States)

    Basu, Rajratan

    2014-03-01

    A small quantity of BaTiO3 ferroelectric nanoparticles (FNP) was doped in a liquid crystal (LC), and the LC +FNP hybrid was found to exhibit an electromechanical memory effect in the isotropic phase. The permanent dipole moment of the FNPs causes the LC molecule to form short-range order surrounding the FNPs. This FNP-induced short-range order becomes more prominent in the isotropic phase when the global nematic order is absent. These short-range domains, being anisotropic in nature, interact with the external electric field. When the field goes off, these domains stay oriented due to the absence of the long range order in the isotropic phase, showing a hysteresis effect. The area under the hysteresis graph shows a significant pretransitional behavior on approaching the nematic phase from the isotropic phase.

  14. Effects of graphene on electro-optic switching and spontaneous polarization of a ferroelectric liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Rajratan, E-mail: basu@usna.edu [Department of Physics, Soft-matter and Nanomaterials Laboratory, The United States Naval Academy, Annapolis, Maryland 21402 (United States)

    2014-09-15

    A small quantity of graphene flakes was doped in a ferroelectric liquid crystal (FLC), and the field-induced ferroelectric electro-optic switching was found to be significantly faster in the FLC + graphene hybrid than that of the pure FLC. Further studies revealed that the suspended graphene flakes enhanced the FLC's spontaneous polarization by improving smectic-C ordering resulting from the π–π electron stacking, and reduced rotation viscosity by trapping some of the free ions of the FLC media. These effects coherently impacted the FLC-switching phenomenon, enabling the FLC molecules to switch faster on reversing an external electric field.

  15. Numerical Study on Deformation and Interior Flow of a Droplet Suspended in Viscous Liquid under Steady Electric Fields

    Directory of Open Access Journals (Sweden)

    Zhentao Wang

    2014-07-01

    Full Text Available A model based on the volume of fluid (VOF method and leaky dielectric theory is established to predict the deformation and internal flow of the droplet suspended in another vicious fluid under the influence of the electric field. Through coupling with hydrodynamics and electrostatics, the rate of deformation and internal flow of the single droplet are simulated and obtained under the different operating parameters. The calculated results show that the direction of deformation and internal flow depends on the physical properties of fluids. The numerical results are compared with Taylor's theory and experimental results by Torza et al. When the rate of deformation is small, the numerical results are consistent with theory and experimental results, and when the rate is large the numerical results are consistent with experimental results but are different from Taylor's theory. In addition, fluid viscosity hardly affects the deformation rate and mainly dominates the deformation velocity. For high viscosity droplet spends more time to attain the steady state. The conductivity ratio and permittivity ratio of two different liquids affect the direction of deformation. When fluid electric properties change, the charge distribution at the interface is various, which leads to the droplet different deformation shapes.

  16. Mechanism of diffusion in the smectic- A phase of wormlike rods studied by computer simulation

    Science.gov (United States)

    Cinacchi, Giorgio; de Gaetani, Luca

    2009-01-01

    Molecular dynamics computer simulations have been carried out in the smectic- A phase of stiff wormlike rods. The analysis of the long trajectories generated has allowed for a detailed insight into that diffusion mechanism which is operative in the above-mentioned liquid-crystalline phase, as recently visualized in a system of colloidal virus rods. Fast particles, i.e., those able to move abruptly out from one into an adjacent layer, have been identified. Their properties, such as the velocity autocorrelation function and the orientational distribution function, have been determined and compared to the corresponding quantities valid for a generic rod.

  17. Instabilities in liquid crystals

    CERN Document Server

    Barclay, G J

    1998-01-01

    and we examine the differences which occur for differing dielectric anisotropies. Finally, in Chapter 7 we study how a sample of smectic C liquid crystal behaves when it is subjected to a uniform shear flow within the smectic plane. We find travelling wave solutions for the behaviour of the c-director and adapt these solutions to incorporate the effects of an applied field. This thesis contains theoretical work dealing with the effects of magnetic and electric fields on samples of nematic, smectic A and smectic C liquid crystals. Some background material along with the continuum theory is introduced in Chapter 2. In Chapter 3 we consider the effect on the director within an infinite sample of nematic liquid crystal which is subjected to crossed electric and magnetic fields. In particular we examine the stability of the travelling waves which describe the director motion by considering the behaviour of the stable perturbations as time increases. The work of Chapter 4 examines a bounded sample of smectic A liqu...

  18. Influence of stabilizer systems on the properties and phase behavior of supercooled smectic nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Koch, Michel H J; Steiniger, Frank

    2010-01-01

    Colloidal dispersions of cholesterol esters in the supercooled smectic state (supercooled smectic nanoparticles) are potential novel carrier systems for poorly water soluble drugs. As the supercooled smectic state is metastable, evaluation of its stability and of parameters influencing it is esse......Colloidal dispersions of cholesterol esters in the supercooled smectic state (supercooled smectic nanoparticles) are potential novel carrier systems for poorly water soluble drugs. As the supercooled smectic state is metastable, evaluation of its stability and of parameters influencing...... scattering (DLS), laser diffraction combined with polarization intensity differential scattering (LD-PIDS), synchrotron radiation small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM, negative staining and cryo-preparation). The various...... storage of smectic nanoparticles stabilized with polysorbate 80 in spite of the presence of a fatty acyl group in the molecule suggests that the polar head group (e.g. polyethylene glycol chains) of the emulsifier may also play a significant role....

  19. Transitional subphases near the electric-field-induced phase transition to the ferroelectric phase in Se-containing chiral smectic liquid crystals observed by resonant x-ray scattering.

    Science.gov (United States)

    Iida, Atsuo; Takanishi, Yoichi; Fukuda, Atsuo; Vij, Jagdish K

    2016-11-01

    Resonant x-ray scattering experiments revealed transitional subphases near the electric-field-induced phase transition of a Se-containing chiral liquid crystal in a planar aligned cell geometry. In the lower-temperature range (Sm-C_{A}^{*} and three-layer periodicity Sm-C_{γ}^{*} phases), the six-layer periodicity subphase appeared with increasing electric field during the field-induced transition from Sm-C_{γ}^{*} to Sm-C^{*}. In the higher-temperature range [four-layer periodicity antiferroelectric (AF) phase], the peak positions of the three-layer satellites shifted to those of the four-layer satellites and then the satellites corresponding to the five- through seven-layer periodicity appeared in sequence. Near the AF to Sm-C_{α}^{*} phase transition temperature, the layer periodicity increased with applied field. The molecular configurations of the subphases near the field-induced transition are discussed based on the Ising, distorted clock, and perfect clock models.

  20. Nematic and Smectic Mesophases from a Novel Triphenylene ...

    African Journals Online (AJOL)

    Salisu Abdulsalam

    phenylazo)azobenzene on to the 2,3,6,7,10,11-hexahydroxytriphenylene nucleus. The presence of a nematic and smectic A ... rod-shaped azobenzene moieties via short (C3) alkyl chains using ester bonds. This compound shows ..... derivatives of hexaalkoxytriphenylene, J. Mol. Liq, Liq Cryst, 411: 1335-1346. Cojocariu C.

  1. Suspended microfluidics

    OpenAIRE

    Casavant, Benjamin P.; Berthier, Erwin; Theberge, Ashleigh B.; Jean BERTHIER; Montanez-Sauri, Sara I.; Bischel, Lauren L.; Brakke, Kenneth; Hedman, Curtis J.; Bushman, Wade; Keller, Nancy P.; Beebe, David J.

    2013-01-01

    Although the field of microfluidics has made significant progress in bringing new tools to address biological questions, the accessibility and adoption of microfluidics within the life sciences are still limited. Open microfluidic systems have the potential to lower the barriers to adoption, but the absence of robust design rules has hindered their use. Here, we present an open microfluidic platform, suspended microfluidics, that uses surface tension to fill and maintain a fluid in microscale...

  2. From antiferroelectricity to ferroelectricity in smectic mesophases ...

    Indian Academy of Sciences (India)

    This contribution gives an overview of ferroelectric switching liquid crystalline phases formed by bent-core molecules. First a description of some general principles behind the mesophase formation within bent-core systems will be given, followed by a short review of the mesophase structures formed by such molecules.

  3. Behavior of the smectic A phase of colloidal goethite in a magnetic field

    NARCIS (Netherlands)

    van den Pol, E.; Petukhov, A.V.; Byelov, D.; Thies-Weesie, D.M.E.; Snigirev, A.; Snigireva, I.; Vroege, G.J.

    2010-01-01

    The behavior of the smectic A phase of colloidal goethite in a magnetic field has been studied using small-angle X-ray scattering. It was found that in systems with a high polydispersity the smectic phase aligns parallel to a small field and it transforms into a columnar phase in high fields. In

  4. NMR studies of liquid crystals and molecules dissolved in liquid crystal solvents

    Energy Technology Data Exchange (ETDEWEB)

    Drobny, Gary Peter [Univ. of California, Berkeley, CA (United States)

    1982-11-01

    This thesis describes several studies in which nuclear magnetic resonance (nmr) spectroscopy has been used to probe the structure, orientation and dynamics of liquid crystal mesogens and molecules dissolved in liquid crystalline phases. In addition, a modern high field nmr spectrometer is described which has been used to perform such nmr studies. Chapter 1 introduces the quantum mechanical formalisms used throughout this thesis and briefly reviews the fundamentals of nuclear spin physics and pulsed nmr spectroscopy. First the density operator is described and a specific form for the canonical ensemble is derived. Then Clebsch-Gordon coefficients, Wigner rotation matrices, and irreducible tensor operators are reviewed. An expression for the equilibrium (Curie) magnetization is obtained and the linear response of a spin system to a strong pulsed r.f. irradiation is described. Finally, the spin interaction Hamiltonians relevant to this work are reviewed together with their truncated forms. Chapter 2 is a deuterium magnetic resonance study of two 'nom' liquid crystals which possess several low temperature mesomorphic phases. Specifically, deuterium quadrupolar echo spectroscopy is used to determine the orientation of the liquid crystal molecules in smectic phases, the changes in molecular orientation and motion that occur at smectic-smectic phase transitions, and the order of the phase transitions. For both compounds, the phase sequence is determined to be isotropic, nematic, smectic A, smectic C, smectic BA, smectic BC, and crystalline. The structure of the smectic A phase is found to be consistent with the well-known model of a two dimensional liquid in which molecules are rapidly rotating about their long axes and oriented at right angles to the plane of the layers. Molecules in the smectic C phase are found to have their long axes tilted with respect to the layer normal, and the tilt angle is temperature dependent, increasing from

  5. Dendritic liquid-crystalline fullerene–ferrocene dyads

    OpenAIRE

    Campidelli, Stéphane; Pérez, Laura; Rodríguez-López Julián; Barberá, Joaquín; Langa, Fernando; Deschenaux, Robert

    2008-01-01

    First- and second-generation ferrocene-based dendrimers, fullerene and a second-generation liquid-crystalline poly(arylester) dendrimer carrying four cyanobiphenyl units were assembled to elaborate polyfunctional materials displaying mesomorphic and electronic properties. The targeted compounds gave rise to enantiotropic smectic A phases and organized into bilayer structures within the smectic layers. Cyclic voltammetry investigations revealed oxidation and reduction processes in agreement wi...

  6. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... This system exhibits the biaxial smectic A phase down to 30°C. Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmAdb liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bilayer smectic structure ...

  7. Synchrotron X-ray studies of liquid-vapor interfaces

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1986-01-01

    The density profile ρ(z) across a liquid-vapor interface may be determined by the reflectivity R(θ) of X-rays at grazing angle incidence θ. The relation between R(θ) and ρ(z) is discussed, and experimental examples illustrating thermal roughness of simple liquids and smectic layering of liquid...

  8. Crystallization behavior of supercooled smectic cholesteryl myristate nanoparticles containing phospholipids as stabilizers

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Koch, Michel; Drechsler, M

    2005-01-01

    Supercooled smectic nanoparticles based on physiological cholesterol esters are under investigation as a potential novel carrier system for lipophilic drugs. The present study investigates the very complex crystallization behavior of such nanoparticles stabilized with the aid of phospholipids. Ph...

  9. Probing the Texture of the Calamitic Liquid Crystalline Dimer of 4-(4-Pentenyloxybenzoic Acid

    Directory of Open Access Journals (Sweden)

    Maher A. Qaddoura

    2010-01-01

    Full Text Available The liquid crystalline dimer of 4-(4-pentenyloxybenzoic acid, a member of the n-alkoxybenzoic acid homologous series, was synthesized using potassium carbonate supported on alumina as catalyst. The acid dimer complex exhibited three mesophases; identified as nematic, smectic X1 and smectic X2. Phase transition temperatures and the corresponding enthalpies were recorded using differential scanning calorimetry upon both heating and cooling. The mesophases were identified by detailed texture observations by variable temperature polarized light microscopy. The nematic phase was distinguished by a fluid Schlieren texture and defect points (four and two brushes while the smectic phases were distinguished by rigid marble and mosaic textures, respectively.

  10. Order, Disorder and Stretching of a Smectic Elastomer with ‘side-on’ Mesogenic Side Groups

    Energy Technology Data Exchange (ETDEWEB)

    de Jeu, W.; Komp, A; Obraztsov, E; Ostrovskii, B; Finkelmann, H

    2009-01-01

    We report an X-ray study of the order in a 'side-on' smectic-A elastomer in which both the polymer backbone and the mesogenic side groups are, on average, parallel to the smectic layer normal. The present system shows in all phases locally correlated structures as evidenced by systematic diffuse scattering at small angles, attributed to the fluorinated end groups of the mesogens. The elastomer shows order of the smectic layers over a limited range in spite of the relatively low crosslink concentration (4%). Upon stretching along the layer normal we find a linear increase of the smectic layer period for small loading (elastic regime). These changes parallel the stress variation for the elastic part of the macroscopic stress-strain curve and saturate at larger strains. The attendant increase in the width of the X-ray peaks indicates a decrease of the average domain dimensions. In the plastic regime no distortion of the smectic monodomain structure or layer rotation is observed. Instead the stress is relieved by 'melting' of the layer structure giving rise to a nematic-like state with short-range layer correlations: at the final stage about four smectic layers.

  11. Goethite liquid crystals and magnetic field effects

    NARCIS (Netherlands)

    van den Pol, E

    2010-01-01

    In this thesis the liquid crystal phase behavior of colloidal, boardlike, goethite (alpha-FeOOH) particles is described. Apart from the nematic phase, a smectic A phase is formed in systems with a low and high polydispersity. Strong fractionation occurs which is able to reduce the local length

  12. Electro-optical and dielectric properties of a high tilt antiferroelectric liquid crystal mixture (W-193B)

    Energy Technology Data Exchange (ETDEWEB)

    Nayek, Prasenjit; Ghosh, Sharmistha; Kundu, Sudarshan; Roy, Subir Kr [Department of Spectroscopy, Indian Association for the Cultivation of Science, Jadavpur, Calcutta-700032 (India); Majumder, Tapas Pal [Department of Physics, University of Kalyani, Kalyani-741235, West Bengal (India); Bennis, Noureddine; Oton, Jose Manuel [Department of TecnologIa Fotonica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Dabrowski, Roman, E-mail: spskr@iacs.res.i [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland)

    2009-11-21

    The electro-optical properties and dielectric relaxation have been investigated for an antiferroelectric liquid crystal mixture W-193B. The material exhibits smectic A*, smectic C* and a wide range of anticlinic smectic C{sub A}{sup *} phases. The high tilt and broad room temperature smectic C{sub A}{sup *} phase make it a good candidate for antiferroelectric display materials. Dielectric studies have been made in a planarly aligned cell in the frequency range 10 Hz-13 MHz. Dielectric spectroscopy reveals the existence of soft mode in the smectic A* phase and Goldstone mode in the smectic C* phase. In the smectic C{sub A}{sup *} phase the dielectric spectrum of the material exhibits two absorption peaks related to the rotational fluctuation around the short axis of the molecules and antiphase azimuthal angle fluctuation, respectively, and are separated by about two orders of frequency. Electro-optical response using a low frequency triangular wave showed a very high quasi-static contrast ratio of 132 : 1, threshold voltage of around 7 V and saturation of 17 V. Surface-stabilized, low thickness cells of this mixture showed a perfect double hysteresis loop with a 1 Hz triangular signal, reaching different transmission levels for different voltage amplitudes. These levels can be stabilized with a single holding voltage, making it possible for the material to be passively multiplexed at video rate.

  13. Method for analysis of psychopharmaceuticals in real industrial wastewater and groundwater with suspended organic particulate matter using solid phase extraction disks extraction and ultra-high performance liquid chromatography/time-of-flight mass spectrometry.

    Science.gov (United States)

    Křesinová, Zdena; Linhartová, Lucie; Petrů, Klára; Krejčová, Lucie; Šrédlová, Kamila; Lhotský, Ondřej; Kameník, Zdeněk; Cajthaml, Tomáš

    2016-04-01

    A rapid and reliable analytical method was developed for the quantitative determination of psychopharmaceuticals, their precursors and by-products in real contaminated samples from a pharmaceutical company in Olomouc (Czech Republic), based on SPE disk extraction and detection by ultra performance liquid chromatography, combined with time-of-flight mass spectrometry. The target compounds were quantified in the real whole-water samples (water including suspended particles), both in the presence of suspended particulate matter (SPM) and high concentrations of other organic pollutants. A total of nine compounds were analyzed which consisted of three commonly used antidepressants (tricyclic antidepressants and antipsychotics), one antitussive agent and five by-products or precursors. At first, the SPE disk method was developed for the extraction of water samples (dissolved analytes, recovery 84-104%) and pressurised liquid extraction technique was verified for solid matrices (sludge samples, recovery 81-95%). In order to evaluate the SPE disk technique for whole water samples containing SPM, non contaminated groundwater samples were also loaded with different amounts (100 and 300mgL(-1)) of real contaminated sludge originating from the same locality. The recoveries from the whole-water samples obtained by SPE disk method ranged between 67 and 119% after the addition of the most contaminated sludge. The final method was applied to several real groundwater (whole-water) samples from the industrial area and high concentrations (up to 10(3)μgL(-1)) of the target compounds were detected. The results of this study document and indicate the feasibility of the SPE disk method for analysis of groundwater. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The Experimental Research and the Quantum and Thermotics Theory Analysis of Lethal Effect of CO{sub 2} Laser Irradiation on Yeast Suspended in Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hongwei; Zhang Lili; Zhang Canbang; Zhou Lingyun [Department of Physics, Honghe University, Mengzi, 661100 (China); Xu Lin, E-mail: zhhw7272@126.com [Department of Physics, Yunnan Normal University, Kunming, 650092 (China)

    2011-02-01

    In this paper, a lethal effect experiment was carried out, in which the biological cells of suspension-industrial saccharomyces cervisiac Sachromyce 2.1189 in liquid was irradiated by CO{sub 2} laser. The experiment results were analyzed by means of quanta theory and thermotics theory. The theoretic analysis results can explain well the experimental results of the lethal effect.

  15. Calamitic Smectic A-Polar Smectic APA Transition Observed in Bent Molecules with Large Bent-Angle Central Core of 4,6-Dichlorobenzene and Alkylthio Terminal Tail

    Science.gov (United States)

    Nguyen, Ha; Kang, Sungmin; Tokita, Masatoshi; Watanabe, Junji

    2011-07-01

    New homologs of bent molecules with a large bent-angle central core of 4,6-dichloro benzene and an alkylthio terminal tail have been synthesized. Although the corresponding alkoxy-tail homologs show only the calamitic phases because of its large bent angles around 160°, the new homologs with an alkylthio tail exhibit the antiferroelectric smectic APA (SmAPA) banana phase that is transformed on cooling from the calamitic smectic A (SmA) phase. The biaxial polar packing of bent molecules in the SmAPA phase is considered to arise from the hindered rotation around the molecular long axis due to the expansion of the mesophase temperatures to a lower temperature region. This study indicates that the bent molecules, even with a large bent angle, have the potential to form a switchable banana phase with a remarkable decrease in its phase temperature range to around 60 °C.

  16. Interplay between columnar and smectic stability in suspensions of polydisperse colloidal platelets.

    Science.gov (United States)

    Velasco, Enrique; Martínez-Ratón, Yuri

    2014-01-14

    The phase behavior of a model suspension of colloidal polydisperse platelets is studied using density-functional theory. Platelets are modelled as parallel rectangular prisms of square section l(2) and height h, with length and height distributions given by different polydispersities δ(l) and δ(h). The model is intended to qualitatively represent experimental colloidal platelet suspensions at high densities with a high degree of orientational ordering. We obtain the phase behavior of the model, including nematic, smectic and columnar phases and its dependence on the two polydispersities δ(l) and δ(h). When δ(l) > δ(h) we observe that the smectic phase stabilises first with respect to the columnar. If δ(h) > δ(l) we observe the opposite behavior. Other more complicated cases occur, e.g. the smectic stabilises from the nematic first but then exists a first-order transition to the columnar phase. Our model assumes plate-rod symmetry, but the regions of stability of smectic and columnar phases are non-symmetric in the δ(l) - δ(h) plane due to the different dimensionality of ordering in the two phases. Microsegregation effects, i.e. different spatial distribution for different sizes within the periodic cell, take place in both phases and, in each case, is more apparent in the variable associated with ordering.

  17. Nano-Segregation of Squalane between Smectic Layers of Rigid-Rod Polysilane

    National Research Council Canada - National Science Library

    Tanaka, Takuya; Kato, Itsuki; Okoshi, Kento

    2015-01-01

    ...-(S)-2-methylbutylsilane] (PDMS), with narrow molecular weight distributions, and a spherical branched alkane, squalane, were investigated by synchrotron radiation small- and wide-angle X-ray scattering (SR-SAXS and SR-WAXS) and atomic force microscopy (AFM) observations and found to reproduce the predicted segregation between the smectic layers. [DOI: 10.1380/ejssnt.2015.121

  18. An interlaboratory study as useful tool for proficiency testing of chemical oxygen demand measurements using solid substrates and liquid samples with high suspended solid content.

    Science.gov (United States)

    Raposo, F; de la Rubia, M A; Borja, R; Alaiz, M; Beltrán, J; Cavinato, C; Clinckspoor, M; Demirer, G; Diamadopoulos, E; Helmreich, B; Jenicek, P; Martí, N; Méndez, R; Noguerol, J; Pereira, F; Picard, S; Torrijos, M

    2009-11-15

    In 2008, the first Proficiency Testing Scheme of Chemical Oxygen Demand (1(st)COD-PT(ADG)) was conducted to assess the results obtained for different research groups whose field work is mainly anaerobic digestion. This study was performed using four samples, two solid samples as raw materials and two solid samples to prepare high concentration suspended solid solutions. Invitations were sent to a large number of laboratories, mainly to anaerobic digestion research groups. Finally, thirty labs from sixteen countries agreed to participate, but for different reasons four participants could not send any data. In total, twenty-six results were reported to the COD-PT coordinator. This study showed the importance of continuous participation in proficiency testing (PT) schemes in order to compare the results obtained. Taking into account the lack of a general standard method and high quality certified reference materials (CRMs), the traceability of COD determination is not currently easy to check. In addition, the spread of participants' results obtained was high and pointed to the advisability of using consensus values due to their unreliability. Therefore, the theoretical oxygen demand (ThOD) values were considered as assigned values for all the samples analysed. On the other hand, in this PT the established standard deviation (ESD) has been determined by the Horwitz modified function. Participants of this 1(st)COD-PT(ADG) were asked to give a short report on the analytical method used. Although all the participants used potassium dichromate as their oxidant reagent, their experimental procedures were very different. With the purpose of comparing the results obtained, the different experimental conditions used were classified into five methods, corresponding to two main categories, open and closed reflux. The performance of laboratories was expressed by the z-score, whose value is considered satisfactory when z-score

  19. On some liquid crystalline phases exhibited by compounds made of ...

    Indian Academy of Sciences (India)

    Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmA db liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bi- layer smectic structure formed by the rods. We also describe unusual growth patterns obtained when.

  20. Photo-orientation at liquid crystal–polymer interfaces

    Indian Academy of Sciences (India)

    The observations are interpreted by assuming that in the smectic and nematic phases the liquid crystal stabilises to a large extent polymer chain-segments aligned parallel to the director, while it blocks the photo-induced formation of chain-segments in the perpendicular direction. Other situations, in which the coupling ...

  1. Asymmetric flavone-based liquid crystals: synthesis and properties

    Energy Technology Data Exchange (ETDEWEB)

    Timmons, Daren J. [Department of Chemistry, Virginia Military Institute, Lexington, VA, USA; Jordan, Abraham J. [Department of Chemistry, Virginia Military Institute, Lexington, VA, USA; Kirchon, Angelo A. [Department of Chemistry, Virginia Military Institute, Lexington, VA, USA; Murthy, N. Sanjeeva [New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, NJ, USA; Siemers, Troy J. [Department of Applied Mathematics, Virginia Military Institute, Lexington, VA, USA; Harrison, Daniel P. [Department of Chemistry, Virginia Military Institute, Lexington, VA, USA; Slebodnick, Carla [Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA

    2017-02-01

    A series of flavones (n-F) substituted at the 4', and 6 positions was prepared, characterised by NMR (1H,13C), HRMS, and studied for liquid crystal properties. The 4'-alkoxy,6-methoxyflavones (4-F–16-F) exhibit varying ranges of nematic and smectic A phases as evidenced by polarised optical microscopy and differential scanning calorimetry (DSC). As the tail length is increased, the smectic phase becomes more prevalent. Smectic phases for (8-F–16-F) were further analysed by powder X-ray diffraction (XRD), and the rate of structural transformations was explored by combined DSC/XRD studies. Flavonol 6-F–OH was also prepared but no mesogenic behaviour was observed. The molecular structures of 6-F and 6-F–OH were determined by single-crystal XRD and help to explain the differences in material properties. Additionally, fluorescence and electrochemical studies were conducted on solutions of n-F.

  2. Highly anisotropic conductivity in organosiloxane liquid crystals

    Science.gov (United States)

    Gardiner, D. J.; Coles, H. J.

    2006-12-01

    In this paper, we present the conductivity and dielectric characterization of three homologous series of smectic A siloxane containing liquid crystals. The materials studied include one monomesogenic series, which consists of a 4-(ω-alkyloxy)-4'-cyanobiphenyl unit terminated by pentamethyldisiloxane, and two bimesogenic series, which consist of twin 4-(ω-alkyloxy)-4'-cyanobiphenyls joined via tetramethyldisiloxane or decamethylpentasiloxane. All of the compounds exhibit wide temperature range enantiotropic smectic A phases; the effect of the siloxane moiety is to suppress nematic morphology even in the short chain homologs. We find that these compounds exhibit a highly anisotropic conductivity: the value perpendicular to the director is to up to 200 times that parallel to the director. For the nonsiloxane analog 4-(ω-octyl)-4'-cyanobiphenyl (8CB), this value is approximately 2. It is also found that the dielectric anisotropy is reduced significantly; a typical value is ˜1 compared to 8.4 for 8CB. We propose that the origin of these unusual properties is in the smectic structure; the microphase separation of the bulky, globular siloxane moieties into liquidlike regions severely inhibits the mobility parallel to the director and across the smectic layers. Further, the inclusion of this unit acts to increase the antiparallel correlations of molecular dipoles in the aromatic and alkyloxy sublayers, reducing the dielectric anisotropy significantly compared to nonsiloxane analogs. The highly anisotropic conductivity suggests that these materials are particularly suitable for application in electro-optic effects which exploit this property, e.g., the bistable electro-optic effect in smectic A liquid crystals.

  3. Dynamics of point defects and stripe textures in Smectic-C Langmuir monolayers.

    Science.gov (United States)

    Vallvé, M A; Ignés-Mullol, J

    2009-12-01

    Langmuir monolayers of an azobenzene fatty acid derivative have been studied experimentally in a regime where confined domains with Smectic-C order form spontaneously. Coalescence of domains results in a dynamics of formation and annihilation of point defects and string-like distortions of the molecular field amenable to semi-quantitative analysis. Absence of backflow and layer thickness effects enables us to extract values for material parameters from the analysis of defect dynamics.

  4. Combustion Studies of Acoustically Suspended Liquid Droplets.

    Science.gov (United States)

    1988-03-01

    VA 22217 Redstone Arsenal, AL 35898 I CommanderCommander Naval Air Systems Command US Army Missile and Space ATTN: J. Ramnarace, Intelligence Center...ATTN: K. Brezinsky I. Glassman 1 Virginia Polytechnic P.O. Box 710 Institute and Princeton, NJ 08540 State University ATTN: J.A. Schetz Princeton

  5. Cable suspended windmill

    Science.gov (United States)

    Farmer, Moses G. (Inventor)

    1990-01-01

    A windmill is disclosed which includes an airframe having an upwind end and a downwind end. The first rotor is rotatably connected to the airframe, and a generator is supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

  6. Mesomorphic and physicochemical properties of liquid crystal mixture composed of chiral molecules with perfluorinated terminal chains

    Science.gov (United States)

    Tomczyk, Wojciech; Marzec, Monika; Juszyńska-Gałązka, Ewa; Węgłowska, Dorota

    2017-02-01

    New binary mixture of thermotropic liquid crystalline compounds, possessing both ferro- and antiferroelectric smectic C* phases, has been studied by complementary methods: calorimetric, X-ray powder diffractometry and electro-optic. Additionally, quantum-chemical model based on the density functional theory was also applied. It was found that mixture studied did not exhibit antiferroelectric phase at any rate of heating or cooling in contradiction to its ingredients. On the other hand it has a wide temperature range of ferroelectric smectic C* phase, which is invariant with respect to different heating and cooling rates within the range of thermal hysteresis. Furthermore, temperature dependence of switching time and spontaneous polarization were measured.

  7. Antiferroelectric surface layers in a liquid crystal as observed by synchrotron x-ray scattering

    DEFF Research Database (Denmark)

    Gramsbergen, E. F.; de Jeu, W. H.; Als-Nielsen, Jens Aage

    1986-01-01

    The X-ray reflectivity form the surface of a liquid crystal with terminally polar (cyano substituted) molecules has been studied using a high-resolution triple-axis X-ray spectrometer in combination with a synchrotron source. It is demonstrated that at the surface of the smectic Al phase a few...

  8. Liquid Crystal Foams Generated by Pressure-Driven Microfluidic Devices.

    Science.gov (United States)

    Shi, Shuojia; Yokoyama, Hiroshi

    2015-04-21

    Thermotropic liquid crystals possess superior foaming capability without the aid of surfactants because of the anisotropic molecular structures. We developed a T-junction microfluidic device to inject gas bubbles of uniform size into a liquid crystal in the nematic and the smectic phases. The bubble size is primarily determined by the dimension of microfluidic channel regardless of the phase, and air bubbles of a few tens of micrometer diameter were stably injected at the rate up to 110 Hz to the close packing density with a polydispersity less than 4%. It is shown that an efficient path to fabricate stable liquid crystal foams is to inject bubbles in the nematic phase, where the highest injection rate is possible, and promptly cool it down to the smectic phase.

  9. Influence of preparation conditions and heat treatment on the properties of supercooled smectic cholesteryl myristate nanoparticles

    DEFF Research Database (Denmark)

    Kuntsche, Judith; Bunjes, H

    2007-01-01

    with a phospholipid/bile salt blend were evaluated. For effective particle size reduction homogenization with high pressure and at temperatures above the melting temperature of the cholesterol ester (isotropic melt) is necessary. Homogenization at lower temperature where the matrix lipid is in the smectic state...... stability of cholesteryl myristate nanoparticles stabilized with different surface active agents during heat treatment was investigated as well. The dispersions were characterized by particle size and zeta potential measurements, differential scanning calorimetry (DSC) and high performance thin layer...

  10. Electric-field-dependent dielectric response in the de Vries-type smectic- A* phase possessing local orientational order with nanoscale correlation length

    OpenAIRE

    VIJ, JAGDISH; MANNA, UTTAM; SONG, JANG-KUN

    2008-01-01

    PUBLISHED The dielectric strength is shown to increase and the relaxation frequency to decrease for a large temperature range up to a certain value of the electric field in the smectic-A* phase. This behavior contrasts to that observed in a conventional smectic-A*, but can be explained in terms of de Vries scenerio. On assuming the reorientation of the molecular dipoles with electric field to be of the Langevin type in the de Vries smectic-A*, we find that around 1300 molecules, correspond...

  11. Dispersive suspended microextraction.

    Science.gov (United States)

    Yang, Zhong-Hua; Liu, Yu; Lu, Yue-Le; Wu, Tong; Zhou, Zhi-Qiang; Liu, Dong-Hui

    2011-11-14

    A novel sample pre-treatment technique termed dispersive suspended microextraction (DSME) coupled with gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of eight organophosphorus pesticides (ethoprophos, malathion, chlorpyrifos, isocarbophos, methidathion, fenamiphos, profenofos, triazophos) in aqueous samples. In this method, both extraction and two phases' separation process were performed by the assistance of magnetic stirring. After separating the two phases, 1 μL of the suspended phase was injected into GC for further instrument analysis. Varieties of experiment factors which could affect the experiment results were optimized and the following were selected: 12.0 μL p-xylene was selected as extraction solvent, extraction speed was 1200 rpm, extraction time was 30 s, the restoration speed was 800 rpm, the restoration time was 8 min, and no salt was added. Under the optimum conditions, limits of detections (LODs) varied between 0.01 and 0.05 μg L(-1). The relative standard deviation (RSDs, n=6) ranged from 4.6% to 12.1%. The linearity was obtained by five points in the concentration range of 0.1-100.0 μg L(-1). Correlation coefficients (r) varied from 0.9964 to 0.9995. The enrichment factors (EFs) were between 206 and 243. In the final experiment, the developed method has been successfully applied to the determination of organophosphorus pesticides in wine and tap water samples and the obtained recoveries were between 83.8% and 101.3%. Compared with other pre-treatment methods, DSME has its own features and could achieve satisfied results for the analysis of trace components in complicated matrices. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Liquid Crystals for Organic Field-Effect Transistors

    Science.gov (United States)

    O'Neill, Mary; Kelly, Stephen M.

    Columnar, smectic and lamellar polymeric liquid crystals are widely recognized as very promising charge-transporting organic semiconductors due to their ability to spontaneously self-assemble into highly ordered domains in uniform thin films over large areas. The transport properties of smectic and columnar liquid crystals are discussed in Chaps. 2 (10.1007/978-90-481-2873-0_2) and 3 (10.1007/978-90-481-2873-0_3). Here we examine their application to organic field-effect transistors (OFETs): after a short introduction in Sect. 9.1 we introduce the OFET configuration and show how the mobility is measured in Sect. 9.2. Section 9.3 discusses polymeric liquid crystalline semiconductors in OFETs. We review research that shows that annealing of polymers in a fluid mesophase gives a more ordered microcrystalline morphology on cooling than that kinetically determined by solution processing of the thin film. We also demonstrate the benefits of monodomain alignment and show the application of liquid crystals in light-emitting field-effect transistors. Some columnar and smectic phases are highly ordered with short intermolecular separation to give large π-π coupling. We discuss their use in OFETs in Sects. 9.4, and 9.5 respectively. Section 9.6 summarises the conclusions of the chapter.

  13. Liquid-crystalline rigid-core semiconductor oligothiophenes: influence of molecular structure on phase behaviour and thin-film properties.

    Science.gov (United States)

    Melucci, Manuela; Favaretto, Laura; Bettini, Christian; Gazzano, Massimo; Camaioni, Nadia; Maccagnani, Piera; Ostoja, Paolo; Monari, Magda; Barbarella, Giovanna

    2007-01-01

    The design, synthesis and properties of liquid-crystalline semiconducting oligothiophenes containing dithienothiophene (DTT), benzothiadiazole (BTZ) and carbazole (CBZ) rigid cores are described. The effect of molecular structure (shape, size and substitution) on their thermal behaviour and electrical properties has been investigated. Polarised optical microscopy (POM) and differential scanning calorimetry (DSC) analyses have revealed highly ordered smectic mesophases for most of the newly synthesised compounds. X-ray diffraction (XRD) studies performed at various temperatures have shown that the smectic order is retained in the crystalline state upon cooling across the transition temperature, affording cast films with a more favourable morphology for FET applications.

  14. Synthesis and properties of cholesteryl 4-(Alkanoylamino)benzoates: liquid crystals and organogelators.

    Science.gov (United States)

    Kubo, Kanji; Tsuji, Kazuki; Mori, Akira; Ujiie, Seiji

    2014-01-01

    As a new liquid crystal and organogelator, cholesteryl 4-(alkanoylamino)benzoates were prepared. Cholesteryl 4-(alkanoylamino)benzoates had enantiotropic cholesteric and chiral smectic C phases. Furthermore cholesteryl 4-(alkanoylamino)benzoates gelled organic liquid such as 1-decanol, linalool, geraniol, nerol, citronellol, linalyl acetate, lavender oil, orange oil, and rose oil. The terpene and perfume gels show good release characteristics of the volatile components for a long period.

  15. The cone phase of liquid crystals: Triangular lattice of double-tilt ...

    Indian Academy of Sciences (India)

    the cut-off α =20 ˚A, double-tilt cylinders of radius R <200 ˚A are energetically favoured over a distortion-free smectic-C provided κG < -3 x10 6 dyne. We are not aware of any measurements of κG in thermotropic liquid crystals. However, some lyotropic liquid crystals have κG values of this sign and magnitude [14]. It is clear ...

  16. Polarization field effects at liquid-crystal-droplet-polymer interfaces.

    Science.gov (United States)

    Boussoualem, Mourad; Ismaili, Mimoun; Lamonier, Jean-François; Buisine, Jean-Marc; Roussel, Frédérick

    2006-04-01

    The influence of confinement (droplet size) and liquid crystal orientational order (smectic-A and nematic) on the interfacial polarization field effects [Maxwell-Wagner-Sillars (MWS) effect] existing in liquid-crystal-droplets-polymer systems is investigated by broadband dielectric spectroscopy and a forward transmittance measurement technique. A relaxation process observed in the low frequency domain of the dielectric spectrum has been associated with a MWS effect for both micron-size and submicron-size droplets. Using electro-optical measurements and numerical simulations of the field inside droplets, it is shown that a depolarization field takes place in the same frequency range as that determined by dielectric spectroscopy. Differential scanning calorimetry measurements allowed to estimate the phase-separated liquid crystal [4,4'-octylcyanobiphenyl (8CB)] fraction, which was found in the range of 55% for both micron-size and submicron-size droplets. X-ray diffraction experiments showed that smectic 8CB confined to micron-size cavities adopt bulklike properties, i.e., a partial bilayer structure, whereas in submicron-size droplets the layer spacing of the smectic phase is increased due to the strong bending deformations induced by the high curvature of the cavity walls.

  17. Spontaneous formation of stringlike clusters and smectic sheets for colloidal rods confined in thin wedgelike gaps.

    Science.gov (United States)

    Maeda, Hideatsu; Maeda, Yoshiko

    2013-08-20

    Monodispersed colloidal rods of β-FeOOH with sizes ranging from 270 to 580 nm in length and 50 to 80 nm in width were synthesized. Narrow wedgelike gaps (0 to 700 nm in height) were formed around the inner bottom edge of the suspension glass cells. Optical microscopic observations revealed the formation of stringlike clusters of the rods and smectic sheets (by spontaneous side-by-side clustering of the strings) in the isotropic phase of the rod suspensions confined in narrow gaps; the electrolyte (HCl) concentrations of the suspensions are 5-40 mM, at which inter-rod interactions are attractive. The strings exhibit different colors that were used to investigate the structures of the strings with the help of interference color theory for thin films. The results are as follows. (1) The rods, lying flat on the gap bottom, are connected side-by-side and stacked upward to form stringlike clusters with different thicknesses depending on the gap height. (2) The stacking numbers (N(sr)) of the rods are estimated to be 1-5. With N(sr) increasing from 2 to 5, the volume fractions (ϕ) of the rods in the strings increased typically from 0.25-0.3 to 0.35-0.42 to reach limiting values (close to the ϕ values of the rods in the bulk smectic phase). (3) Unexpected low-ϕ strings are found in regions with an intermediate height in the gaps. These behaviors of ϕ may be caused by thermal fluctuations of the strings.

  18. New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction; Nouvelles etudes structurales de cristaux liquides par reflectivite et diffraction resonante des rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, P

    2007-04-15

    This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B{sub 2} liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B{sub 2} phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation.

  19. Local structural ordering in surface-confined liquid crystals

    Science.gov (United States)

    Śliwa, I.; Jeżewski, W.; Zakharov, A. V.

    2017-06-01

    The effect of the interplay between attractive nonlocal surface interactions and attractive pair long-range intermolecular couplings on molecular structures of liquid crystals confined in thin cells with flat solid surfaces has been studied. Extending the McMillan mean field theory to include finite systems, it has been shown that confining surfaces can induce complex orientational and translational ordering of molecules. Typically, local smectic A, nematic, and isotropic phases have been shown to coexist in certain temperature ranges, provided that confining cells are sufficiently thick, albeit finite. Due to the nonlocality of surface interactions, the spatial arrangement of these local phases can display, in general, an unexpected complexity along the surface normal direction. In particular, molecules located in the vicinity of surfaces can still be organized in smectic layers, even though nematic and/or isotropic order can simultaneously appear in the interior of cells. The resulting surface freezing of smectic layers has been confirmed to occur even for rather weak surface interactions. The surface interactions cannot, however, prevent smectic layers from melting relatively close to system boundaries, even when molecules are still arranged in layers within the central region of the system. The internal interfaces, separating individual liquid-crystal phases, are demonstrated here to form fronts of local finite-size transitions that move across cells under temperature changes. Although the complex molecular ordering in surface confined liquid-crystal systems can essentially be controlled by temperature variations, specific thermal properties of these systems, especially the nature of the local transitions, are argued to be strongly conditioned to the degree of molecular packing.

  20. Side-chain liquid-crystalline poly(ketone)s : effect of spacer length, mesogen type and mesogen density on mesomorphic behavior

    NARCIS (Netherlands)

    Nieuwhof, R.P.; Marcelis, A.T.M.; Sudhölter, E.J.R.; Wursche, R.; Rieger, B.

    2000-01-01

    Novel side-chain liquid-crystalline copolymers (SCLCPs) were synthesized via the Pd(II) catalyzed alternating copolymerization of mesogenic 1-alkenes and carbon monoxide. For methoxybiphenyl mesogens, these copolymers exhibited highly ordered smectic E mesophases and high glass transition

  1. Self-Suspended Suspensions of Covalently Grafted Hairy Nanoparticles

    KAUST Repository

    Choudhury, Snehashis

    2015-03-17

    © 2015 American Chemical Society. Dispersions of small particles in liquids have been studied continuously for almost two centuries for their ability to simultaneously advance understanding of physical properties of fluids and their widespread use in applications. In both settings, the suspending (liquid) and suspended (solid) phases are normally distinct and uncoupled on long length and time scales. In this study, we report on the synthesis and physical properties of a novel family of covalently grafted nanoparticles that exist as self-suspended suspensions with high particle loadings. In such suspensions, we find that the grafted polymer chains exhibit unusual multiscale structural transitions and enhanced conformational stability on subnanometer and nanometer length scales. On mesoscopic length scales, the suspensions display exceptional homogeneity and colloidal stability. We attribute this feature to steric repulsions between grafted chains and the space-filling constraint on the tethered chains in the single-component self-suspended materials, which inhibits phase segregation. On macroscopic length scales, the suspensions exist as neat fluids that exhibit soft glassy rheology and, counterintuitively, enhanced elasticity with increasing temperature. This feature is discussed in terms of increased interpenetration of the grafted chains and jamming of the nanoparticles. (Chemical Presented).

  2. Development of a microfluidic interface for suspended microchannel resonators

    OpenAIRE

    Maillard, Damien

    2016-01-01

    Suspended microchannel resonators (SMRs) are devices that detect particles in liquid samples. In comparison with similar resonating devices that must be immersed, SMRs allow the fluids to flow through microfluidic resonators. This principle of operation leads to a great reduction of the required sample and to enhanced quality factors. As such, SMRs show great potential for a variety of sensing applications. This thesis reports on the final steps of the microfabrication of SMRs and on the deve...

  3. Suspended animation for delayed resuscitation.

    Science.gov (United States)

    Safar, Peter J; Tisherman, Samuel A

    2002-04-01

    'Suspended animation for delayed resuscitation' is a new concept for attempting resuscitation from cardiac arrest of patients who currently (totally or temporarily) cannot be resuscitated, such as traumatic exsanguination cardiac arrest. Suspended animation means preservation of the viability of brain and organism during cardiac arrest, until restoration of stable spontaneous circulation or prolonged artificial circulation is possible. Suspended animation for exsanguination cardiac arrest of trauma victims would have to be induced within the critical first 5 min after the start of cardiac arrest no-flow, to buy time for transport and resuscitative surgery (hemostasis) performed during no-flow. Cardiac arrest is then reversed with all-out resuscitation, usually requiring cardiopulmonary bypass. Suspended animation has been explored and documented as effective in dogs in terms of long-term survival without brain damage after very prolonged cardiac arrest. In the 1990s, the Pittsburgh group achieved survival without brain damage in dogs after cardiac arrest of up to 90 min no-flow at brain (tympanic) temperature of 10 degrees C, with functionally and histologically normal brains. These studies used emergency cardiopulmonary bypass with heat exchanger or a single hypothermic saline flush into the aorta, which proved superior to pharmacologic strategies. For the large number of normovolemic sudden cardiac death victims, which currently cannot be resuscitated, more research in large animals is needed.

  4. X-Ray Reflectivity from the Surface of a Liquid Crystal:

    DEFF Research Database (Denmark)

    Pershan, P.S.; Als-Nielsen, Jens Aage

    1984-01-01

    X-ray reflectivity from the surface of a nematic liquid crystal is interpreted as the coherent superposition of Fresnel reflection from the surface and Bragg reflection from smectic order induced by the surface. Angular dependence of the Fresnel effect yields information on surface structure. Mea....... Measurement of the intensity of diffuse critical scattering relative to the Fresnel reflection yields the absolute value of the critical part of the density-density correlation function.......X-ray reflectivity from the surface of a nematic liquid crystal is interpreted as the coherent superposition of Fresnel reflection from the surface and Bragg reflection from smectic order induced by the surface. Angular dependence of the Fresnel effect yields information on surface structure...

  5. 7 CFR 1206.21 - Suspend.

    Science.gov (United States)

    2010-01-01

    ... part thereof during a particular period of time specified in the rule. ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means to...

  6. Intramolecular Charge Transfer of Conjugated Liquid Crystal Ferrocene Macromolecules - Synthesis and Characterization

    Science.gov (United States)

    2016-04-12

    Smectic A (SA) or C (SC) phases of tetramers and pentamers, to the fluidic Nematic (N) phase of the heptamers and octamers. These liquid crystalline ...al.) and CIQA by linear absorption and emission spectroscopy, laser flash photolysis, ultrafast laser femtosecond time-resolved absorption spectra...30 minutes and then the reaction is stopped by passing it thought a plug of silica gel. After the THF evaporation, the product is dried in vacuum

  7. Dynamic behaviour of a ferro-electric liquid crystal by means of nuclear magnetic resonance and dielectric spectroscopy

    Science.gov (United States)

    Domenici, Valentina; Marini, Alberto; Menicagli, Rita; Veracini, Carlo Alberto; Bubnov, Aleksej M.; Glogarova, Milada

    2007-05-01

    The field of ferroelectric liquid crystals (FLCs) is one of the most fascinating aspects of the Science of Materials for their interesting electro-optic applications. Among different chemical and physical properties those related to the molecular dynamics are very stimulating due to the relationship between molecular motions and macroscopic response to external fields, such as electric and magnetic ones. In this work, the molecular dynamics of a ferroelectric smectogen, namely the (S)-2-methylbutyl-[4'-(4"-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2')-benzoyl)-propionyl)]-propionate (ZLL 7/*) has been investigated by means of 2H NMR and dielectric relaxation techniques. The first method allows us to get information on the molecular motions in the fast motion regime, in particular the diffusion reorientational motions of the whole molecule, as well as of the internal motions affecting the phenyl and biphenyl fragments. The second technique, which covers the slow motion regime, has been used to detect collective motions and fluctuation modes. This study allows us to have a complete idea of molecular motions in the different smectic phases formed by the ZLL 7/* mesogens, in particular the paraelectric smectic A (SmA), the ferroelectric smectic C* (SmC*), the antiferroelectric smectic C* A (SmC* A) and the re-entrant ferroelectric smectic C* (SmC* r) phases. This last phase has been investigated for the first time in this work, from the point of view of the dynamic behaviour. All results will be discussed in the framework of the molecular dynamics of ferroelectric liquid crystals, reported in the literature so far.

  8. Features of the sorption redistribution of hydrocarbons and alcohols in a gas-supramolecular liquid crystal system

    Science.gov (United States)

    Onuchak, L. A.; Ukolova, D. A.; Burmatnova, T. S.; Kuraeva, Yu. G.; Kuvshinova, S. A.; Burmistrov, V. A.; Stepanova, R. F.

    2015-01-01

    Thermodynamic characteristics of the sorption redistribution of hydrocarbons (C8-C12 n-alkanes, C10H16 terpenes, xylene isomers) and alcohols (C3-C5 alkanols, butanediol-2,3, menthol) in a gas-4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) supramolecular smectic-nematic liquid crystal system are studied via inverse gas chromatography. The sorption capacity of HPOFAB with respect to nonmesogene sorbates is found to be strongly diminished due to its associated structure, especially in the smectic A phase. Great positive deviations from the Raoult law in the studied nonmesogene-HPOFAB systems are observed not only in mesophases, but also in the isotropic HPOFAB phase, which has a high selectivity to para- and meta-xylenes, in contrast to the isotropic phases of classic (non-associated) liquid crystals.

  9. Rippling instabilities in suspended nanoribbons

    Science.gov (United States)

    Wang, Hailong; Upmanyu, Moneesh

    2012-11-01

    Morphology mediates the interplay between the structure and electronic transport in atomically thin nanoribbons such as graphene as the relaxation of edge stresses occurs preferentially via out-of-plane deflections. In the case of end-supported suspended nanoribbons that we study here, past experiments and computations have identified a range of equilibrium morphologies, in particular, for graphene flakes, yet a unified understanding of their relative stability remains elusive. Here, we employ atomic-scale simulations and a composite framework based on isotropic elastic plate theory to chart out the morphological stability space of suspended nanoribbons with respect to intrinsic (ribbon elasticity) and engineered (ribbon geometry) parameters, and the combination of edge and body actuation. The computations highlight a rich morphological shape space that can be naturally classified into two competing shapes, bendinglike and twistlike, depending on the distribution of ripples across the interacting edges. The linearized elastic framework yields exact solutions for these rippled shapes. For compressive edge stresses, the body strain emerges as a key variable that controls their relative stability and in extreme cases stabilizes coexisting transverse ripples. Tensile edge stresses lead to dimples within the ribbon core that decay into the edges, a feature of obvious significance for stretchable nanoelectronics. The interplay between geometry and mechanics that we report should serve as a key input for quantifying the transport along these ribbons.

  10. Electro-optic study of antiferroelectric freely suspended films of bent-core mesogens in the B2 phase.

    Science.gov (United States)

    Stannarius, Ralf; Langer, Christian; Weissflog, Wolfgang

    2002-09-01

    We report the electro-optic investigation of a liquid crystalline free standing film formed by bent-core (banana-shaped) mesogens. The ground state of the B2 phase in the films is chiral and antiferroelectric, although the mesogenic molecules themselves lack chirality. The films can be switched in lateral electric fields. In the antiferroelectric ground state, the external electric field in the film plane couples to a small residual spontaneous polarization which we attribute to the incomplete compensation of polarizations of neighboring smectic layers, due to a nonzero twist normal to the layers. We derive viscoelastic parameters from the uniform switching dynamics and the structure of domain walls. Dynamic patterns in rotating fields are observed and analyzed.

  11. Self-suspended permanent magnetic FePt ferrofluids

    KAUST Repository

    Dallas, Panagiotis

    2013-10-01

    We present the synthesis and characterization of a new class of self-suspended ferrofluids that exhibit remanent magnetization at room temperature. Our system relies on the chemisorption of a thiol-terminated ionic liquid with very low melting point on the surface of L10 FePt nanoparticles. In contrast, all types of ferrofluids previously reported employ either volatile solvents as the suspending media or superparamagnetic iron oxide nanoparticles (that lacks permanent magnetization) as the inorganic component. The ferrofluids do not show any sign of flocculation or phase separation, despite the strong interactions between the magnetic nanoparticles due to the strong chemisorption of the ionic liquid as evidenced by Raman spectroscopy and thermal analysis. Composites with high FePt loading (40 and 70. wt%) exhibit a pseudo solid-like rheological behavior and high remanent magnetization values (10.1 and 12.8. emu/g respectively). At lower FePt loading (12. wt%) a liquid like behavior is observed and the remanent and saturation magnetization values are 3.5 and 6.2. emu/g, respectively. The magnetic and flow properties of the materials can be easily fine tuned by controlling the type and amount of FePt nanoparticles used. © 2013 Elsevier Inc.

  12. New chiral liquid crystal with unconventional dioxane terminal unit

    Czech Academy of Sciences Publication Activity Database

    Perkowski, P.; Bubnov, Alexej; Mrukiewicz, M.; Pociecha, D.; Piecek, W.; Hamplová, Věra; Kašpar, Miroslav

    2014-01-01

    Roč. 87, 10-11 (2014), s. 1024-1037 ISSN 0141-1594 R&D Projects: GA MŠk 7AMB13PL041; GA MŠk(CZ) LD14007; GA MŠk(CZ) 7AMB14PL035; GA ČR GA13-14133S Grant - others:AV ČR(CZ) M100101211; AVČR(CZ) M100101204; EU - ICT(XE) COST Action IC1208 Institutional support: RVO:68378271 Keywords : chiral liquid crysta * pentaglyform unit * structural properties * smectic phase * hexagonal ordering * self-assembling Subject RIV: JJ - Other Materials Impact factor: 0.954, year: 2014

  13. Stepwise transition of a topological defect from the smectic film to the boundary of a dipolar inclusion

    Science.gov (United States)

    Dolganov, P. V.; Kats, E. I.; Cluzeau, P.

    2010-03-01

    Cholesteric droplets accompanied by a topological defect are studied in free standing smectic C∗ films. We observed a transition between two droplet-defect configurations with the defect in the film and on the droplet boundary. We found that the distance between the droplet surface and the topological defect decreases continuously with increasing temperature and above a certain critical temperature the defect jumps to the droplet boundary. We relate this stepwise change in the defect position to the change in the anchoring on the droplet boundary. This transformation leads to a decrease in the interparticle distances in self-organized chains from droplets. Our simple theory allows us to estimate the value of the anchoring energy.

  14. Spherical microparticles with Saturn ring defects and their self-assembly across the nematic to smectic-A phase transition.

    Science.gov (United States)

    Zuhail, K P; Čopar, S; Muševič, I; Dhara, Surajit

    2015-11-01

    We report experimental studies on the Saturn ring defect associated with a spherical microparticle across the nematic (N) to smectic-A (SmA) phase transition. We observe that the director distortion around the microparticle changes rapidly with temperature. The equilibrium interparticle separation and the angle between two quadrupolar particles in the N phase are larger than those of the SmA phase. They are almost independent of the temperature in both phases, except for a discontinuous jump at the transition. We assembled a few particles using a laser tweezer to form a two-dimensional colloidal crystal in the N phase. The lattice structure of the crystal dissolves irreversibly across the N-SmA phase transition. The results on the pretransitional behavior of the defect are supported by the Landau-de Gennes Q-tensor modeling.

  15. Asymmetric van der Waals forces drive orientation of compositionally anisotropic nanocylinders within smectic arrays: experiment and simulation.

    Science.gov (United States)

    Smith, Benjamin D; Fichthorn, Kristen A; Kirby, David J; Quimby, Lisa M; Triplett, Derek A; González, Pedro; Hernández, Darimar; Keating, Christine D

    2014-01-28

    Understanding how micro- and nanoparticles interact is important for achieving bottom-up assembly of desired structures. Here, we examine the self-assembly of two-component, compositionally asymmetric nanocylinders that sediment from solution onto a solid surface. These particles spontaneously formed smectic arrays. Within the rows of an array, nanocylinders tended to assemble such that neighboring particles had the same orientation of their segments. As a probe of interparticle interactions, we classified nanocylinder alignments by measuring the segment orientations of many sets of neighboring particles. Monte Carlo simulations incorporating an exact expression for the van der Waals (vdW) energy indicate that differences in the vdW interactions, even when small, are the key factor in producing observed segment alignment. These results point to asymmetrical vdW interactions as a potentially powerful means of controlling orientation in multicomponent cylinder arrays, and suggest that designing for these interactions could yield new ways to control self-assembly.

  16. Strain sensitivity enhancement in suspended core fiber tapers

    Science.gov (United States)

    André, Ricardo M.; Silva, Susana O.; Becker, Martin; Schuster, Kay; Rothardt, M.; Bartelt, H.; Marques, Manuel B.; Frazão, Orlando

    2013-06-01

    Suspended core fiber tapers with different cross sections (with diameters from 70 μm to 120 μm) are produced by filament heating. Before obtaining the taper, the spectral behavior of the suspended core fiber is a multimode interference structure. When the taper is made, an intermodal interference between a few modes is observed. This effect is clearly visible for low taper core dimensions. Since the core and cladding do not collapse, two taper regions exist, one in the core and the other in the cladding. The cladding taper does not affect the light transmission, only the core is reduced to a microtaper. The spectral response of the microtaper based-suspended core fiber is similar to a beat of two interferometers. The strain is applied to the microtaper, and with the reduction in the transverse area, an increase in sensitivity is observed. When the taper is immersed in a liquid with a different index of refraction or subjected to temperature variations, no spectral change occurs.

  17. Abrasion properties of self-suspended hairy titanium dioxide nanomaterials

    Science.gov (United States)

    Zhang, Jiao-xia; Liu, Si; Yan, Chao; Wang, Xiao-jing; Wang, Lei; Yu, Ya-ming; Li, Shi-yun

    2017-10-01

    Considering the excellent solubility of pyrrolidone ring organic compounds, the synthesized N-(trimethoxysilyl) propyl-N-methyl-2-pyrrolidone chlorides was tethered onto titanium dioxide (TiO2) nanoparticles to improve dispersion of TiO2, and then polyethylene oxide (PEO) oligomer through ion exchange embraced the tethered TiO2 to obtain a novel self-suspended hairy TiO2 nanomaterials without any solvent. A variety of techniques were carried out to illustrate the structure and properties of the self-suspended hairy TiO2 nanomaterials. It was found that TiO2 nanoparticles embody monodispersity in the hybrid system though the "false reunion" phenomenon occurring due to nonpermanent weak physical cross-linking. Remarkably, self-suspended hairy TiO2 nanomaterials exhibit lower viscosity, facilitating maneuverable and outstanding antifriction and wear resistance properties, due to the synergistic lubricating effect between spontaneously forming lubricating film and nano-lubrication of TiO2 cores, overcoming the deficiency of both solid and liquid lubricants. This make them promising candidates for the micro-electromechanic/nano-electromechanic systems (MEMS/NEMS).

  18. 23 Elemental Composition of Suspended Particulate Matter ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    Elemental Composition of Suspended Particulate Matter Collected at Two Different. Heights above the Ground in A Sub-Urban Site in Kenya. Gitari W. M1, Kinyua A. M. 2, Kamau G. N3 and C. K. Gatebe C. K4. Abstract. Suspended particulate matter samples were collected in a sub-urban area in Nairobi over a 12 month ...

  19. Investigation of singularities in superfluid He/sup 3/ in liquid crystals by the homotopic topology methods

    Energy Technology Data Exchange (ETDEWEB)

    Volovik, G.E.; Mineev, V.P.

    1977-06-01

    Various singularities in the superfluid He/sup 3/ are considered: vortices, disgyrations, pointlike singularities, vortices with ends, singular surfaces, and particle-like states, as well as disclinations in cholesteric liquid crystals. A classification is presented of the topologically stable singularities. The methods of homotopic topology are used and are described with examples of well known systems such as superfluid He II, an isotropic ferromagnet, and a nematic liquid crystal. The possibility of applying these methods to ordinary crytals and to liquid crytals of the smectic type is discussed.

  20. Pulsed zero field NMR of solids and liquid crystals

    Energy Technology Data Exchange (ETDEWEB)

    Thayer, A.M.

    1987-02-01

    This work describes the development and applications to solids and liquid crystals of zero field nuclear magnetic resonance (NMR) experiments with pulsed dc magnetic fields. Zero field NMR experiments are one approach for obtaining high resolution spectra of amorphous and polycrystalline materials which normally (in high field) display broad featureless spectra. The behavior of the spin system can be coherently manipulated and probed in zero field with dc magnetic field pulses which are employed in a similar manner to radiofrequency pulses in high field NMR experiments. Nematic phases of liquid crystalline systems are studied in order to observe the effects of the removal of an applied magnetic field on sample alignment and molecular order parameters. In nematic phases with positive and negative magnetic susceptibility anisotropies, a comparison between the forms of the spin interactions in high and low fields is made. High resolution zero field NMR spectra of unaligned smectic samples are also obtained and reflect the symmetry of the liquid crystalline environment. These experiments are a sensitive measure of the motionally induced asymmetry in biaxial phases. Homonuclear and heteronuclear solute spin systems are compared in the nematic and smectic phases. Nonaxially symmetric dipolar couplings are reported for several systems. The effects of residual fields in the presence of a non-zero asymmetry parameter are discussed theoretically and presented experimentally. Computer programs for simulations of these and other experimental results are also reported. 179 refs., 75 figs.

  1. Speckle noise suppression using a helix-free ferroelectric liquid crystal cell

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, A L; Andreeva, T B; Kompanets, I N [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Zalyapin, N V [National Research Nuclear University ' ' MEPhI' ' (Russian Federation)

    2014-12-31

    We have studied the method for suppressing speckle noise in patterns produced by a laser based on a fast-response electro-optical cell with a ferroelectric liquid crystal (FLC) in which helicoid is absent, i.e., compensated for. The character of smectic layer deformation in an electric field is considered along with the mechanism of spatially inhomogeneous phase modulation of a laser beam passing through the cell which is accompanied by the destruction of phase relations in the beam. Advantages of a helix-free FLC cell are pointed out as compared to helical crystal cells studied previously. (liquid crystal devices)

  2. Geometric methods in the elastic theory of membranes in liquid crystal phases

    CERN Document Server

    Ji Xing Liu; Yu Zhang Xie

    1999-01-01

    This book contains a comprehensive description of the mechanical equilibrium and deformation of membranes as a surface problem in differential geometry. Following the pioneering work by W Helfrich, the fluid membrane is seen as a nematic or smectic - A liquid crystal film and its elastic energy form is deduced exactly from the curvature elastic theory of the liquid crystals. With surface variation the minimization of the energy at fixed osmotical pressure and surface tension gives a completely new surface equation in geometry that involves potential interest in mathematics. The investigations

  3. Forces in Liquid Metal Contacts

    DEFF Research Database (Denmark)

    Duggen, Lars; Mátéfi-Tempfli, Stefan

    2014-01-01

    Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review...... of the necessary theory and find numerically the forces to be in the 100μN range for liquid metals as mercury and liquid Gallium suspended between electrodes of 20μm radius....

  4. Phase transition behavior of hydrogen bonded liquid crystal (6BA){sub 2}-(BPy){sub x} as studied by {sup 2}H NMR

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, M., E-mail: mizuno@se.kanazawa-u.ac.jp; Tabota, K.; Oigawa, T.; Miyatou, T.; Kumagai, Y.; Ohashi, R.; Ida, T. [Kanazawa University, Department of Chemistry, Graduate School of Natural Science & Technology (Japan)

    2016-12-15

    The thermal properties and the orientational order of hydrogen-bonded liquid crystals (6BA){sub 2}-(BPy){sub 0.4} and (6BA){sub 2}-(BPy){sub 0.3} (6BA: 4-n-hexylbenzoicacid, BPy: 4,4’-bipyridine) were investigated by DSC and {sup 2}H NMR. On cooling, isotropic liquid - liquid crystal phase transition temperatures were T{sub C}= 409 and 405 K for (6BA){sub 2}-(BPy){sub 0.4} and (6BA){sub 2}-(BPy){sub 0.3}, respectively. Thermal anomalies in the liquid crystal phase were observed at T{sub LC1}= 402 and T{sub LC2}= 375 K for (6BA){sub 2}-(BPy){sub 0.4} and at T{sub LC1}= 398 and T{sub LC2}= 375 K for (6BA){sub 2}-(BPy){sub 0.3}. For (6BA){sub 2}-(BPy){sub 0.4}, only the smectic component was created above T{sub LC1}. In addition, the nematic component was created below T{sub LC1}. The nematic component gradually changed to the smectic component with decreasing temperature and only the smectic component was observed below T{sub LC2}. For (6BA){sub 2}-(BPy){sub 0.3}, only the nematic component was created above T{sub LC2}. The phase transition from the nematic phase to the smectic phase took place at around T{sub LC2}.

  5. Improving suspended sediment measurements by automatic samplers.

    Science.gov (United States)

    Gettel, Melissa; Gulliver, John S; Kayhanian, Masoud; DeGroot, Gregory; Brand, Joshua; Mohseni, Omid; Erickson, Andrew J

    2011-10-01

    Suspended solids either as total suspended solids (TSS) or suspended sediment concentration (SSC) is an integral particulate water quality parameter that is important in assessing particle-bound contaminants. At present, nearly all stormwater runoff quality monitoring is performed with automatic samplers in which the sampling intake is typically installed at the bottom of a storm sewer or channel. This method of sampling often results in a less accurate measurement of suspended sediment and associated pollutants due to the vertical variation in particle concentration caused by particle settling. In this study, the inaccuracies associated with sampling by conventional intakes for automatic samplers have been verified by testing with known suspended sediment concentrations and known particle sizes ranging from approximately 20 μm to 355 μm under various flow rates. Experimental results show that, for samples collected at a typical automatic sampler intake position, the ratio of sampled to feed suspended sediment concentration is up to 6600% without an intake strainer and up to 300% with a strainer. When the sampling intake is modified with multiple sampling tubes and fitted with a wing to provide lift (winged arm sampler intake), the accuracy of sampling improves substantially. With this modification, the differences between sampled and feed suspended sediment concentration were more consistent and the sampled to feed concentration ratio was accurate to within 10% for particle sizes up to 250 μm.

  6. Delineating Effects of Ionic Strength and Suspended Solids on Ammonia Volatilization from Dairy Manure Slurry

    Science.gov (United States)

    Koirala, K.

    2014-12-01

    Ammonia emission is a major concern due to its adverse effects on animal and human health. Ionic strength and suspended solids play key roles in the ammonia volatilization process. These two parameters, however, are usually lumped together in form of total solids. The objective of this study was to separate the contribution of suspended solids (SS) from that of ionic strength (IS) on ammonia volatilization in liquid dairy manure. A two-way factorial experiment was conducted to simultaneously test the effects of IS and SS on ammonium dissociation: a key element of the ammonia volatilization process. The fraction of ammonia (β) in total ammoniacal nitrogen (TAN) was experimentally determined in a convective emission chamber, for each level of SS and IS, at a constant wind speed of 1.5 m s-1, and air and liquid temperature of 25°C. The two way analysis of variance showed a significant effect of SS concentration (p = 0.04) on fraction of ammonia in the liquid dairy manure, while the effect of ionic strength was marginal (p = 0.05). The highest dissociation of ammonium was observed in manure with the lowest SS concentration (0%) and the lowest ionic strength (0.10 mol L-1). Significant increases in suspended solids concentration and ionic strength were necessary to influence the ammonium dissociation in dairy manure. Results revealed that substantially high content of suspended solids (> 3.0%) or relatively high dilution of manure with water (30%) were necessary for these two parameters to play significant roles in the ammonia volatilization mechanism in liquid dairy manure. Results also showed that the β was more sensitive to the changes in suspended solids concentration than in the changes in ionic strength within the ranges of SS and IS examined in this study. Overall, the SS and IS effects on ammonium dissociation (and by extension on ammonia volatilization process) were thus found negligible within the normal ranges of liquid dairy manure characteristics.

  7. Magnetically suspended virtual divergent channel

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Ryuichiro [Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515 (Japan)]. E-mail: yamane@kokushikan.ac.jp; Oshiama, Shuzo [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Park, Myeong-Kwan [Pusan National University, 30 Changjeon-dong, Kumjeong-ku, Pusan 609-735 (Korea, Republic of)

    2005-03-15

    Two permanent magnets are set face-to-face and inclined with each other to produce the long cuspidal magnetic field. The diamagnetic liquid is levitated and flows through it without contact with the solid walls as if it is in the virtual divergent channel. Analysis is made on the shape of the virtual channel, and the results are compared with the experimental ones. The divergence angle increases with the increase in the inclination of the magnets.

  8. Computerized Liquid Crystal Phase Identification by Neural Networks Analysis of Polarizing Microscopy Textures

    Science.gov (United States)

    Karaszi, Zoltan; Konya, Andrew; Dragan, Feodor; Jakli, Antal; CPIP/LCI; CS Dept. of Kent State University Collaboration

    Polarizing optical microscopy (POM) is traditionally the best-established method of studying liquid crystals, and using POM started already with Otto Lehman in 1890. An expert, who is familiar with the science of optics of anisotropic materials and typical textures of liquid crystals, can identify phases with relatively large confidence. However, for unambiguous identification usually other expensive and time-consuming experiments are needed. Replacement of the subjective and qualitative human eye-based liquid crystal texture analysis with quantitative computerized image analysis technique started only recently and were used to enhance the detection of smooth phase transitions, determine order parameter and birefringence of specific liquid crystal phases. We investigate if the computer can recognize and name the phase where the texture was taken. To judge the potential of reliable image recognition based on this procedure, we used 871 images of liquid crystal textures belonging to five main categories: Nematic, Smectic A, Smectic C, Cholesteric and Crystal, and used a Neural Network Clustering Technique included in the data mining software package in Java ``WEKA''. A neural network trained on a set of 827 LC textures classified the remaining 44 textures with 80% accuracy.

  9. Finite Element Modeling of Suspended Particle Migration in Non-Newtonian Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Altobelli, S.; Baer, T.; Mondy, L.; Rao, R.; Stephens, T.

    1999-03-04

    Shear-induced migration of particles is studied during the slow flow of suspensions of spheres (particle volume fraction {phi} = 0.50) in an inelastic but shear-thinning, suspending fluid in flow between counterrotating concentric cylinders, The conditions are such that nonhydrodynamic effects are negligible. The movement of particles away from the high shear rate region is more pronounced than in a Newtonian suspending liquid. We test a continuum constitutive model for the evolution of particle concentration in a flowing suspension proposed by Phillips et al. (1992) by using shear-thinning, suspending fluids. The fluid constitutive equation is Carreau-like in its shear-thinning behavior but also varies with the local particle concentration. The model is compared with the experimental data gathered with nuclear magnetic resonance (NMR) imaging.

  10. Study of Hydrophilic Electrospun Nanofiber Membranes for Filtration of Micro and Nanosize Suspended Particles

    Directory of Open Access Journals (Sweden)

    Nurxat Nuraje

    2013-11-01

    Full Text Available Polymeric nanofiber membranes of polyvinyl chloride (PVC blended with polyvinylpyrrolidone (PVP were fabricated using an electrospinning process at different conditions and used for the filtration of three different liquid suspensions to determine the efficiency of the filter membranes. The three liquid suspensions included lake water, abrasive particles from a water jet cutter, and suspended magnetite nanoparticles. The major goal of this research work was to create highly hydrophilic nanofiber membranes and utilize them to filter the suspended liquids at an optimal level of purification (i.e., drinkable level. In order to overcome the fouling/biofouling/blocking problems of the membrane, a coagulation process, which enhances the membrane’s efficiency for removing colloidal particles, was used as a pre-treatment process. Two chemical agents, Tanfloc (organic and Alum (inorganic, were chosen for the flocculation/coagulation process. The removal efficiency of the suspended particles in the liquids was measured in terms of turbidity, pH, and total dissolved solids (TDS. It was observed that the coagulation/filtration experiments were more efficient at removing turbidity, compared to the direct filtration process performed without any coagulation and filter media.

  11. Nanotube networks in liquid crystals

    Science.gov (United States)

    Urbanski, Martin; Lagerwall, Jan Peter F.; Scalia, Giusy

    2016-03-01

    Liquid crystals (LCs) are very attractive hosts for the organization of anisotropic nanoparticles such as carbon nanotubes (CNTs) because of the macroscopic organization resulting in properties of nanoparticles manifest at a macroscopic scale. Different types of LCs have demonstrated the ability to organize nanotubes, showing the generality of the approach, i.e., that the liquid crystallinity per se is the driving factor for the organization. Compared to standard nanotube composites (e.g. with disordered polymer hosts) the introduction of carbon nanotubes into an LC allows not only the transfer of the outstanding CNT properties to the macroscopic phase, providing strength and conductivity, but these properties also become anisotropic, following the transfer of the orientational order from the LC to the CNTs. The LC molecular structure plays an important even if ancillary role since it enters in the surface interactions, fulfilling a mediating action between the particle and the bulk of the LC. Isolated nanotubes can be obtained by optimized dispersions at lower concentrations and this process requires the use or development of tailored strategies like using solvents or even another LC for pre-dispersing CNTs. Aggregates or networks can be observed in poor dispersions and at higher nanoparticle concentrations. In those, due to surface interactions, the LC behaviour can be strongly affected with changes in phase sequences or transition temperatures and the effect is expected to be more pronounced as the concentration of nanotubes increases. We present preliminary investigations and observations on nanotube - LC systems based on a smectic LC host.

  12. Skin permeation of lidocaine from crystal suspended oily formulations.

    Science.gov (United States)

    Matsui, Rakan; Hasegawa, Masaaki; Ishida, Masami; Ebata, Toshiya; Namiki, Noriyuki; Sugibayashi, Kenji

    2005-09-01

    In vitro permeation of lidocaine (lidocaine base, LID) through excised rat skin was investigated using several LID-suspended oily formulations. The first skin permeation of LID from an LID-suspended oily solution such as liquid paraffin (LP), isopropyl myristate (IPM), polyoxyethylene (2) oleylether (BO-2), and diethyl sebacate (DES) was evaluated and compared with that from polyethylene glycol 400 (PEG400) solution, a hydrophilic base. The obtained permeation rate of LID, Japp, from PEG400, LP, IPM, BO-2, and DES was in the order of DES>BO-2=IPM>LP>PEG400, and increased with LID solubility in the oily solvents, although LID crystals were dispersed in all solvents. Subsequently, oily formulations that consisted of different ratios of the first oily solvent (IPM, BO-2, or DES) (each 0-20%), the second oily solvent (LP) and an oily mixture of microcrystalline wax/white petrolatum/paraffin (1/5/4) were evaluated. BO-2 groups at a concentration of 5% and 10% had the highest Japp among the oily formulations, although a higher BO-2 resulted in lower skin permeation. In addition, pretreatment with BO-2 increased the skin permeation of LID. These results suggest that the penetration enhancing effect by the system may be related to the skin penetration of BO-2 itself. Finally, mathematical analysis was done to evaluate the effect of BO-2, and it was shown that BO-2 improved the LID solubility in stratum corneum lipids to efficiently enhance the LID permeation through skin.

  13. Structure and dynamics of a Gay-Berne liquid crystal confined in cylindrical nanopores.

    Science.gov (United States)

    Ji, Qing; Lefort, Ronan; Busselez, Rémi; Morineau, Denis

    2009-06-21

    Gay-Berne liquid crystals confined in two cylindrical nanopores with different pore sizes were studied by molecular dynamics simulation. Their structure and dynamics properties were obtained and compared with those of the bulk. Our data show that confinement changes the bulk isotropic-to-nematic transition to a continuous ordering from a paranematic to a nematic phase. Moreover, confinement strongly hinders the smectic translational order. The molecular dynamics is characterized by the translational diffusion coefficients and the first-rank reorientational correlation times. Very different characteristic times and temperature variations in the dynamics are observed in confinement. Spatially resolved quantities illustrate that confinement induces predominant structural and dynamical heterogeneities.

  14. 9 CFR 201.81 - Suspended registrants.

    Science.gov (United States)

    2010-01-01

    ... 201.81 Animals and Animal Products GRAIN INSPECTION, PACKERS AND STOCKYARDS ADMINISTRATION (PACKERS AND STOCKYARDS PROGRAMS), DEPARTMENT OF AGRICULTURE REGULATIONS UNDER THE PACKERS AND STOCKYARDS ACT Services § 201.81 Suspended registrants. No stockyard owner, packer, market agency, or dealer shall employ...

  15. Electrodialytic remediation of suspended mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrian; Pino, Denisse

    2008-01-01

    experiment at 40 mA, with approximately 137.5 g mine tailings on dry basis. The removal for a static (baseline) experiment only amounted 15% when passing approximately the same amount of charge through 130 g of mine tailings. The use of air bubbling to keep the tailings suspended increased the removal...

  16. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    ... from the control values were found significant at 99% confidence level. Possible inhalatory problems are thus anticipated from prolonged accumulation of the dust in the respiratory system. KEY WORDS: Environmental toxicology, Suspended particulate matter, Dust analysis, Hematological indices, Wister albino rats. Bull.

  17. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    face area, shape, minerals and source) and conse- quent interaction with heavy metal concentrations. (HMCs). Recent studies have shown a growing awareness of the wider environmental significance of the suspended sediment loads transported by rivers and streams. This includes the importance of fine grain sediment in ...

  18. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    The elemental contents of suspended particulate matter (dust) samples from Maiduguri, Nigeria, were determined which showed appreciably high levels for especially Pb, Fe, Cu, Zn, K, Ca, and. Na. Wister albino rats were exposed to graded doses of phosphate buffered saline carried dust particles. The hematological ...

  19. A depth integrated model for suspended transport

    NARCIS (Netherlands)

    Galappatti, R.

    1983-01-01

    A new depth averaged model for suspended sediment transport in open channels has been developed based on an asymptotic solution to the two dimensional convection-diffusion equation in the vertical plane. The solution for the depth averaged concentration is derived from the bed boundary condition and

  20. Flow Laminarization and Acceleration by Suspended Particles

    NARCIS (Netherlands)

    Bertsch, M.; Hulshof, J.; Prostokishin, V.M.

    2015-01-01

    In [Comm. Appl. Math. Comput. Sci., 4(2009), pp. 153-175], Barenblatt presents a model for partial laminarization and acceleration of shear flows by the presence of suspended particles of different sizes, and provides a formal asymptotic analysis of the resulting velocity equation. In the present

  1. Emulsifying and Suspending Properties of Enterolobium ...

    African Journals Online (AJOL)

    Background:The thermodynamic instability of emulsions and suspensions necessitate the incorporation of emulsifiers and suspending agents respectively, in order to stabilize the formulations and ensure administration of accurate doses. Objective:Enterolobium cyclocarpum gum was characterized and evaluated for its ...

  2. Controlling the volatility of the written optical state in electrochromic DNA liquid crystals

    Science.gov (United States)

    Liu, Kai; Varghese, Justin; Gerasimov, Jennifer Y.; Polyakov, Alexey O.; Shuai, Min; Su, Juanjuan; Chen, Dong; Zajaczkowski, Wojciech; Marcozzi, Alessio; Pisula, Wojciech; Noheda, Beatriz; Palstra, Thomas T. M.; Clark, Noel A.; Herrmann, Andreas

    2016-05-01

    Liquid crystals are widely used in displays for portable electronic information display. To broaden their scope for other applications like smart windows and tags, new material properties such as polarizer-free operation and tunable memory of a written state become important. Here, we describe an anhydrous nanoDNA-surfactant thermotropic liquid crystal system, which exhibits distinctive electrically controlled optical absorption, and temperature-dependent memory. In the liquid crystal isotropic phase, electric field-induced colouration and bleaching have a switching time of seconds. Upon transition to the smectic liquid crystal phase, optical memory of the written state is observed for many hours without applied voltage. The reorientation of the DNA-surfactant lamellar layers plays an important role in preventing colour decay. Thereby, the volatility of optoelectronic state can be controlled simply by changing the phase of the material. This research may pave the way for developing a new generation of DNA-based, phase-modulated, photoelectronic devices.

  3. Pattern of liquid crystalline droplets induced by two beam interference in azobenzene derivative

    Science.gov (United States)

    Czajkowski, Maciej; Dradrach, Klaudia; Bartkiewicz, Stanislaw; Galewski, Zbigniew

    2013-10-01

    A pattern of liquid crystalline droplets dispersed in the isotropic liquid can be formed during illumination by two interfering laser beams in certain range of the temperature and the light intensity. Azobenzene derivative substituted by long alkyl and alkoxy chains exhibiting smectic phases has been used for the study. The pattern can be reversibly erased and rewritten by shutting down and opening of the interfering beams. Polarized microscope images have shown the formation of numerous liquid crystalline droplets at bright regions of the interference fringes. Influence of the temperature and the light intensity has been studied by measuring the diffraction efficiency dynamics. Photothermal and photoorientational mechanisms of the formation of liquid crystalline droplets pattern have been proposed and discussed.

  4. Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

    Science.gov (United States)

    Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

    2016-11-02

    Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  6. Utilizing liquid crystal phases to obtain highly ordered thin films for organic electronics

    Science.gov (United States)

    Springer, Mike T.

    Organic electronic materials offer several advantages when compared to inorganic materials, but they suffer from low charge carrier mobility. Two major factors hindering effective charge transport in organic materials are: 1) effective wavefunction overlap in organic crystals and 2) the domain morphology of thin films. Charge transport in organic materials occurs via a hopping mechanism along the conjugated pi system. Often, rigid, aromatic organic materials crystallize in a herringbone, edge-to-face orientation, limiting pi-pi stacking and decreasing charge carrier mobility. Face-to-face orientation of aromatic rings decreases intermolecular pi-pi distances and increases wavefunction overlap. Control of the crystal structure can be achieved to some extent by tuning structural features of the molecule, like increasing the ratio of carbon atoms to hydrogen atoms in the aromatic rings; this is often achieved by introducing heteroatoms like sulfur and oxygen into the aromatic ring structure. Thin films of organic materials often contain many unaligned domains; this is caused by rapid crystallization. Control of the domain morphology of thin films has been shown to increase charge carrier mobility by 6 orders of magnitude for thin films of the same material. Liquid crystal phases allow a slow process of crystallization, whereby the molecules in a thin film can be slowly aligned into a monodomain before crystallization. The crystal-smectic phases, like smectic E, are particularly attractive for this strategy due to their high degree of intermolecular order. This project describes the synthesis and characterization of organic semiconductors designed to exhibit short pi-pi distances and highly ordered crystal-smectic phases to obtain thin films with high charge carrier mobility. The n,2-OBTTT series contains 15 newly designed and synthesized mesogens. The liquid crystal and solid crystal structures of these mesogens are examined and deposition conditions are optimized for

  7. Energy content of suspended detritus from Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Sumitra-Vijayaraghavan; Royan, J.P.

    Energy components of suspended matter included phytoplankton, zooplankton and detritus inclusive of microorganisms adsorbed to detritus. Of these, detritus contributed most of the energy (98%). The average caloric content of suspended detritus...

  8. The suspended sentence in French Criminal Law

    Directory of Open Access Journals (Sweden)

    Jovašević Dragan

    2016-01-01

    Full Text Available From the ancient times until today, criminal law has provided different criminal sanctions as measures of social control. These coercive measures are imposed on the criminal offender by the competent court and aimed at limitting the offender's rights and freedoms or depriving the offender of certain rights and freedoms. These sanctions are applied to the natural or legal persons who violate the norms of the legal order and injure or endanger other legal goods that enjoy legal protection. In order to effectively protect social values, criminal legislations in all countries predict a number of criminal sanctions. These are: 1 imprisonment, 2 precautions, 3 safety measures, 4 penalties for juveniles, and 5 sanctions for legal persons. Apart and instead of punishment, warning measures have a significant role in the jurisprudence. Since they emerged in the early 20th century in the system of criminal sanctions, there has been an increase in their application to criminal offenders, especially when it comes to first-time offenders who committed a negligent or accidental criminal act. Warnings are applied in case of crimes that do not have serious consequences, and whose perpetrators are not hardened and incorrigible criminals. All contemporary criminal legislations (including the French legilation provide a warning measure of suspended sentence. Suspended sentence is a conditional stay of execution of sentence of imprisonment for a specified time, provided that the convicted person does not commit another criminal offense and fulfills other obligations. This sanction applies if the following two conditions are fulfilled: a forma! -which is attached to the sentence of imprisonment; and b material -which is the court assessment that the application of this sanction is justified and necessary in a particular case. In many modern criminal legislations, there are two different types of suspended (conditional sentence: 1 ordinary (classical suspended

  9. Liquid crystalline critical dynamics in decylammonium chloride

    CERN Document Server

    Lee, K W; Lee, C E; Kang, K H; Rhee, C; Kang, J K

    1999-01-01

    Collective chain dynamics and phase transitions in a model biomembrane, decylammonium chloride (C sub 1 sub 0 H sub 2 sub 1 NH sub 3 Cl), were studied by means of proton nuclear magnetic resonance. Our measurements sensitively reflect the critical dynamics associated with the smectic C to smectic A transition of the lipid bilayer.

  10. Estimating total suspended sediment yield with probability sampling

    Science.gov (United States)

    Robert B. Thomas

    1985-01-01

    The ""Selection At List Time"" (SALT) scheme controls sampling of concentration for estimating total suspended sediment yield. The probability of taking a sample is proportional to its estimated contribution to total suspended sediment discharge. This procedure gives unbiased estimates of total suspended sediment yield and the variance of the...

  11. Critical Role of the Spacer Length of Gemini Surfactants on the Formation of Ionic Liquid Crystals and Thermotropic Behavior.

    Science.gov (United States)

    Fernandes, Ricardo M F; Wang, Yujie; Tavares, Pedro B; Nunes, Sandra C C; Pais, Alberto A C C; Marques, Eduardo F

    2017-10-24

    Numerous reports have shown that the self-assembling properties of 12-s-12 bis(quaternary ammonium) gemini surfactants in aqueous solution are significantly influenced by s, the number of methylene groups in the covalent spacer. However, the role played by s on the phase behavior of the single compounds has not been investigated in a similarly systematic way. Here, we report on the thermotropic phase behavior of the anhydrous compounds with s = 2-6, 8, 10 and 12, resorting to differential scanning calorimetry (DSC), polarized light microscopy (PLM) and X-ray diffraction (XRD). All of the compounds show a stepwise melting behavior, decomposing at 200 ºC. As the spacer length increases non-monotonic trends are observed for the thermodynamic parameters of the thermotropic phase transitions, mesophase formation and solid-state d00l spacings. In particular, the number and type of mesophases (ordered smectic phases and/or fluid smectic liquid crystals) depend critically on s. Further, upon heating molecules with s < 8 decompose before the liquid phase, while those with long spacers, s = 8-12, reach the isotropization (clearing) temperature hence forming both ionic liquid crystals and ionic liquid phases. We demonstrate that the melting behavior and type of ionic mesophases formed by gemini molecules can be usefully manipulated by a simple structural parameter like the length of the covalent linker.

  12. Optomechanics for thermal characterization of suspended graphene

    Science.gov (United States)

    Dolleman, Robin J.; Houri, Samer; Davidovikj, Dejan; Cartamil-Bueno, Santiago J.; Blanter, Yaroslav M.; van der Zant, Herre S. J.; Steeneken, Peter G.

    2017-10-01

    The thermal response of graphene is expected to be extremely fast due to its low heat capacity and high thermal conductivity. In this work, the thermal response of suspended single-layer graphene membranes is investigated by characterization of their mechanical motion in response to a high-frequency modulated laser. A characteristic delay time τ between the optical intensity and mechanical motion is observed, which is attributed to the time required to raise the temperature of the membrane. We find, however, that the measured time constants are significantly larger than the predicted ones based on values of the specific heat and thermal conductivity. In order to explain the discrepancy between measured and modeled τ , a model is proposed that takes a thermal boundary resistance at the edge of the graphene drum into account. The measurements provide a noninvasive way to characterize thermal properties of suspended atomically thin membranes, providing information that can be hard to obtain by other means.

  13. Sedimentation of suspended solids in ultrasound field

    Directory of Open Access Journals (Sweden)

    Vikulina Vera

    2018-01-01

    Full Text Available Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

  14. Suspended sediments limit coral sperm availability

    Science.gov (United States)

    Ricardo, Gerard F.; Jones, Ross J.; Clode, Peta L.; Humanes, Adriana; Negri, Andrew P.

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  15. Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level

    CERN Document Server

    Stimson, L M

    2003-01-01

    Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a s...

  16. Dual gauge field theory of quantum liquid crystals in three dimensions

    Science.gov (United States)

    Beekman, Aron J.; Nissinen, Jaakko; Wu, Kai; Zaanen, Jan

    2017-10-01

    The dislocation-mediated quantum melting of solids into quantum liquid crystals is extended from two to three spatial dimensions, using a generalization of boson-vortex or Abelian-Higgs duality. Dislocations are now Burgers-vector-valued strings that trace out worldsheets in space-time while the phonons of the solid dualize into two-form (Kalb-Ramond) gauge fields. We propose an effective dual Higgs potential that allows for restoring translational symmetry in either one, two, or three directions, leading to the quantum analogues of columnar, smectic, or nematic liquid crystals. In these phases, transverse phonons turn into gapped, propagating modes, while compressional stress remains massless. Rotational Goldstone modes emerge whenever translational symmetry is restored. We also consider the effective electromagnetic response of electrically charged quantum liquid crystals, and find among other things that as a hard principle only two out of the possible three rotational Goldstone modes are observable using propagating electromagnetic fields.

  17. Role of the Electrostatic Interactions in the Stabilization of Ionic Liquid Crystals: Insights from Coarse-Grained MD Simulations of an Imidazolium Model.

    Science.gov (United States)

    Saielli, Giacomo; Wang, Yanting

    2016-09-01

    In order to investigate the role of the electrostatic interactions in stabilizing various phases of ionic liquids, especially smectic ionic liquid crystals, we have employed a coarse-grained model of 1-hexadecyl-3-methylimidazolium nitrate, [C16mim][NO3], to perform molecular dynamics simulations with the partial charges artificially rescaled by a factor from 0.7 to 1.2. The simulated systems have been characterized by means of orientational and translational order parameters and by distribution functions. We have found that increasing the total charge of the ions strongly stabilizes the ionic smectic phase by shifting the clearing point (melting into the isotropic liquid phase) to higher temperatures, while a smaller effect is observed on the stability of the crystal phase. Our results highlight the importance of the electrostatic interactions in promoting the formation of ionic liquid crystals through microphase segregation. Moreover, as the total charge of the model is increased, we observe a transformation from a homogeneous to a nanosegregated isotropic structure typical of ionic liquids. Therefore, a connection can be established between the degree of nanosegregation of ILs and the stability of ILC phases. All the above can be understood by the competition among electrostatic interactions between charged groups (cationic head groups and anions), van der Waals interactions between nonpolar cationic tail groups, and thermal fluctuations.

  18. Monitoring of suspended sediment in South Tyrol

    Science.gov (United States)

    Nadalet, Rudi; Dinale, Roberto; Pernter, Martin; Maraldo, Luca; Peterlin, Dieter; Richter, Arnold; Comiti, Francesco

    2016-04-01

    In the context of the EU Water Framework Directive (WFD), which aims to achieve a good status of European water bodies, the Hydrographic Office of the Autonomous Province of Bolzano (Italy) extended in 2014 its institutional activities including the monitoring of suspended sediment in the river channel network. Currently, the only active monitoring station is on the Adige River at the gauging station of Ponte Adige near Bolzano (drainage area 2705 km2). The applied monitoring strategy and the data analysis concept are both based on the guidelines issued by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW). The results indicates that the temporal variability strongly differs during the investigated period (2014-2015). In addition to the analysis of precipitation and water discharge, temperature and lightning activity were also included to better understand the sediment transport dynamics observed at the station. In summer 2015, the combination of constantly high daily temperature throughout the Adige basin (which drove intense glacier melting in the headwaters) with a high frequency of convective rainfall events (90% more than in 2014, obtained through lightning detection), led to an annual mass of transported suspended sediment of 260000 t. Interestingly, this value is similar to the one estimated for 2014 (300000 t), which was characterized by very different meteorological conditions (colder and wetter summer), but with the occurrence of an important flood in August, which transported half of the annual amount. Finally, we can conclude that the adopted monitoring strategy is applicable for institutional aims in terms of costs as well as in terms of time effort. During the next years, other stations for suspended sediment monitoring are planned to be installed in the Province to cover the most important river segments.

  19. Detection of graphene chirality using achiral liquid crystalline platforms

    Science.gov (United States)

    Basu, Rajratan; Kinnamon, Daniel; Garvey, Alfred

    2015-09-01

    Monolayer graphene flakes were dispersed at low concentrations into two achiral liquid crystals (LCs) alkoxyphenylbenzoate (9OO4) and 4-cyano-4'-pentylbiphenyl (5CB), separately. The presence of graphene resulted in two types of chiral signatures in the LCs: an electroclinic effect (a polar tilt of the LC director perpendicular to, and linear in, an applied electric field) in the smectic-A phase of 9OO4, and a macroscopic helical twist of the LC director in the nematic phase of 5CB. Graphene flakes generally possess strain chirality and edge chirality. The non-covalent interactions between the LC molecules and chiral graphene flakes induce molecular conformational deracemization in the LC, exhibiting a bulk electroclinic effect and a macroscopic helical twist.

  20. Active noise cancellation in a suspended interferometer

    CERN Document Server

    Driggers, Jennifer C; Pepper, Keenan; Adhikari, Rana

    2011-01-01

    We demonstrate feed-forward vibration isolation on a suspended Fabry-Perot interferometer using Wiener filtering and a variant of the common Least Mean Square (LMS) adaptive filter algorithm. We compare the experimental results with theoretical estimates of the cancellation efficiency. Using data from the recent LIGO Science Run, we also estimate the impact of this technique on full scale gravitational wave interferometers. In the future, we expect to use this technique to also remove acoustic, magnetic, and gravitational noise perturbations from the LIGO interferometers. This noise cancellation technique is simple enough to implement in standard laboratory environments and can be used to improve SNR for a variety of high precision experiments.

  1. Geodetic monitoring of suspended particles in rivers

    Science.gov (United States)

    Kamnik, Rok; Maksimova, Daria; Kovačič, Boštjan

    2017-10-01

    There is a trend in modern approach to the management of space of collecting the spatial data, in order to obtain useful information. In this paper a research of suspended particles in the river Drava and Mura will be introduced. The goal is to connect different fields of water management in countries where the rivers Drava and Mura flows in purpose of water management sustainability. The methods such as GNSS for mapping cross sections of the river, the use of ADCP (Acoustic Doppler Current Profiler) measurement system and water sampling to monitor sediment in the water will be presented.

  2. Safety Harness For Work Under Suspended Load

    Science.gov (United States)

    Sunoo, Su Young

    1994-01-01

    Safety device protects worker under suspended engine or other heavy load. Mechanically linked with load so if load should fall, worker yanked safely away. Worker wears chest-plate vest with straps crossing eye on back. Lower safety cable connected to eye extends horizontally away from worker to nearby wall, wrapped on pulley and extends upward to motion amplifier or reducer. Safety cables transform any sudden downward motion of overhanging load into rapid sideways motion of worker. Net catches worker, preventing worker from bumping against wall.

  3. Asymmetric Dimers of Chiral Azobenzene Dopants Exhibiting Unusual Helical Twisting Power upon Photoswitching in Cholesteric Liquid Crystals.

    Science.gov (United States)

    Kim, Yuna; Tamaoki, Nobuyuki

    2016-02-01

    In this study, we synthesized asymmetric dimeric chiral molecules as photon-mode chiral switches for reversible tuning of self-assembled helical superstructures. The chiral switches bearing two mesogen units-cholesterol and azobenzene moieties connected through flexible alkylenedioxy bridges-were doped into nematic liquid crystals, resulting in a chiral nematic (cholesteric) phase. Under irradiation with UV light, photoisomerization of the azobenzene units led to unprecedented switching of the cholesteric pitch and helical twisting power (HTP, β), with a higher HTP found in the cis-rich state (bent-form) than in the trans-state (rod-form). We attribute this behavior to the elongated cybotactic smectic clusters disrupting the helical orientation of the molecules in the cholesteric liquid crystals; their reversible decay and reassembly was evidenced upon sequential irradiation with UV and visible light, respectively. In addition to the photoisomerization of the azobenzene units, the odd/even parity of the alkylenedioxy linkers of the dimeric dopants also had a dramatic effect on the transitions of the cybotactic smectic domains. On the basis of the large rotational reorganization of the cholesteric helix and HTP switching (Δβ/βini of up to 50%), we could control the macroscopic rotational motion of microsized glass rods upon irradiating the surface of a cholesteric liquid crystal film featuring a polygonal fingerprint texture using UV and visible light.

  4. Elastic properties of suspended multilayer WSe2

    Science.gov (United States)

    Zhang, Rui; Koutsos, Vasileios; Cheung, Rebecca

    2016-01-01

    We report the experimental determination of the elastic properties of suspended multilayer WSe2, a promising two-dimensional (2D) semiconducting material combined with high optical quality. The suspended WSe2 membranes have been fabricated by mechanical exfoliation of bulk WSe2 and transfer of the exfoliated multilayer WSe2 flakes onto SiO2/Si substrates pre-patterned with hole arrays. Then, indentation experiments have been performed on these membranes with an atomic force microscope. The results show that the 2D elastic modulus of the multilayer WSe2 membranes increases linearly while the prestress decreases linearly as the number of layers increases. The interlayer interaction in WSe2 has been observed to be strong enough to prevent the interlayer sliding during the indentation experiments. The Young's modulus of multilayer WSe2 (167.3 ± 6.7 GPa) is statistically independent of the thickness of the membranes, whose value is about two thirds of other most investigated 2D semiconducting transition metal dichalcogenides, namely, MoS2 and WS2. Moreover, the multilayer WSe2 can endure ˜12.4 GPa stress and ˜7.3% strain without fracture or mechanical degradation. The 2D WSe2 can be an attractive semiconducting material for application in flexible optoelectronic devices and nano-electromechanical systems.

  5. Method for forming suspended micromechanical structures

    Science.gov (United States)

    Fleming, James G.

    2000-01-01

    A micromachining method is disclosed for forming a suspended micromechanical structure from {111} crystalline silicon. The micromachining method is based on the use of anisotropic dry etching to define lateral features of the structure which are etched down into a {111}-silicon substrate to a first etch depth, thereby forming sidewalls of the structure. The sidewalls are then coated with a protection layer, and the substrate is dry etched to a second etch depth to define a spacing of the structure from the substrate. A selective anisotropic wet etchant (e.g. KOH, EDP, TMAH, NaOH or CsOH) is used to laterally undercut the structure between the first and second etch depths, thereby forming a substantially planar lower surface of the structure along a {111} crystal plane that is parallel to an upper surface of the structure. The lateral extent of undercutting by the wet etchant is controlled and effectively terminated by either timing the etching, by the location of angled {111}-silicon planes or by the locations of preformed etch-stops. This present method allows the formation of suspended micromechanical structures having large vertical dimensions and large masses while allowing for detailed lateral features which can be provided by dry etch definition. Additionally, the method of the present invention is compatible with the formation of electronic circuitry on the substrate.

  6. Surface tension of Nanofluid-type fuels containing suspended nanomaterials.

    Science.gov (United States)

    Tanvir, Saad; Qiao, Li

    2012-04-18

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension.

  7. Surface tension of Nanofluid-type fuels containing suspended nanomaterials

    Science.gov (United States)

    2012-01-01

    The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension. PMID:22513039

  8. Environmentally-suspended sediment production of the Nasia River ...

    African Journals Online (AJOL)

    The study assessed the level of suspended sediment produced in the Nasia River Basin. Hydrological and meteorological data and water samples were used for the study. Average suspended sediment yield (33 years) in the basin was 19.90 t/km2/yr. With mean annual runoff of 439.13m3/s, 322.43 t/yr suspended sediment ...

  9. Suspended sediment yield in Texas watersheds

    Science.gov (United States)

    Coonrod, Julia Ellen Allred

    The Texas Water Development Board collected suspended sediment samples across the state of Texas for approximately 60 years. Until this research, no comprehensive analysis of the data had been conducted. This study compiles the suspended sediment data along with corresponding streamflow and rainfall. GIS programs are developed which characterize watersheds corresponding to the sediment gauging stations. The watersheds are characterized according to topography, climate, soils, and land use. All of the data is combined to form several SAS data sets which can subsequently be analyzed using regression. Annual data for all of the stations across the state are classified temporally and spatially to determine trends in the sediment yield. In general, the suspended sediment load increases with increasing runoff but no correlation exists with rainfall. However, the annual average rainfall can be used to classify the watersheds according to climate, which improves the correlation between sediment load and runoff. The watersheds with no dams have higher sediment loads than watersheds with dams. Dams in the drier parts of Texas reduce the sediment load more than dams in the wetter part of the state. Sediment rating curves are developed separately for each basin in Texas. All but one of the curves fall into a band which varies by about two orders of magnitude. The study analyzes daily time series data for the Lavaca River near Edna station. USGS data are used to improve the sediment rating curve by the addition of physically related variables and interaction terms. The model can explain an additional 41% of the variability in sediment concentration compared to a simple bivariate regression of sediment load and flow. The TWDB daily data for the Lavaca River near Edna station are used to quantify temporal trends. There is a high correlation between sediment load and flowrate for the Lavaca River. The correlation can be improved by considering a flow-squared term and by

  10. Coalescence Processes of Droplets and Liquid Marbles

    OpenAIRE

    Jing Jin; Chin Hong Ooi; Dzung Viet Dao; Nam-Trung Nguyen

    2017-01-01

    The coalescence process of droplets and, more recently, of liquid marbles, has become one of the most essential manipulation schemes in digital microfluidics. This process is indispensable for realising microfluidic functions such as mixing and reactions at microscale. This paper reviews previous studies on droplet coalescence, paying particular attention to the coalescence of liquid marbles. Four coalescence systems have been reviewed, namely, the coalescence of two droplets freely suspended...

  11. Liquid filtration simulation

    Energy Technology Data Exchange (ETDEWEB)

    Corey, I.; Bergman, W.

    1996-06-01

    We have a developed a computer code that simulates 3-D filtration of suspended particles in fluids in realistic filter structures. This code, being the most advanced filtration simulation package developed to date, provides LLNL and DOE with new capabilities to address problems in cleaning liquid wastes, medical fluid cleaning, and recycling liquids. The code is an integrated system of commercially available and LLNL-developed software; the most critical are the computational fluid dynamics (CFD) solver and the particle transport program. For the CFD solver, we used a commercial package based on Navier-Stokes equations and a LLNL-developed package based on Boltzman-lattice gas equations. For the particle transport program, we developed a cod based on the 3-D Langevin equation of motion and the DLVO theory of electrical interactions. A number of additional supporting packages were purchased or developed to integrate the simulation tasks and to provide visualization output.

  12. Design consideration for magnetically suspended flywheel systems

    Science.gov (United States)

    Anand, D.; Kirk, J. A.; Frommer, D. A.

    1985-01-01

    Consideration is given to the design, fabrication, and testing of a magnetically suspended flywheel system for energy storage applications in space. The device is the prototype of a system combining passive suspension of the flywheel plate by samarium cobalt magnets and active control in the radial direction using eight separate magnetic coils. The bearing assembly was machined from a nickel-iron alloy, and the machine parts are all hydrogen annealed. Slots in the magnetic plate allow four independent quadrants for control. The motor/generator component of the system is a brushless dc-permanent magnetic/ironless engine using electronic communication. The system has been tested at over 2500 rpm with satisfactory results. The system characteristics of the flywheel for application in low earth orbit (LEO) are given in a table.

  13. Organics and Suspended Solids Removal from Hospital

    Directory of Open Access Journals (Sweden)

    Fakhri Y. Hmood

    2013-05-01

    Full Text Available The Sequencing Batch Reactor (SBR method is used for treating samples of waste water taken from hospitals in Mosul. Many run periods are used (6-24 hours for             6 months. It is found that the organics and suspended solids removal increase with increasing the period of run, it is in the range ( 96-82 % and ( 100-95 % respectively, while the pH values are nearly neutral (7.05 to 7.5.     BOD5 and SS concentrations of the effluent are within the limits of Iraqi standards,  40:30 mg/l respectively. Hence, SBR method could be used for treating hospitals, small factories and some  residential sectors waste waters.  

  14. Batch fabrication of nanotubes suspended between microelectrodes

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Stöckli, T.; Knapp, H. F.

    2007-01-01

    We report a fabrication method, which uses standard UV-lithography to pattern the catalyst for the chemical vapour deposition(CVD) of suspended double clamped single walled carbon nanotubes. By using an aqueous solution of Fe(NO3)3 the patterning of the catalyst material onto microelectrodes can...... be done with a simple lift-off process with standard photolithographic resist. An applied electric field is sustained between the microelectrodes during CVD to guide the nanotube growth. Comparison with simulations shows that the location and the orientation of the grown carbon nanotubes (CNT) correspond...... to the regions of maximum electric field, enabling accurate positioning of a nanotube by controlling the shape of the microelectrodes. The CNT bridges are deflected tens of nm when a DC voltage is applied between the nanotube and a gate microelectrode indicating that the clamping through the catalyst particles...

  15. Cholesteric Liquid Crystalline Copolymers for Gas Chromatographic Separation of Polycyclic Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin

    2012-01-01

    Full Text Available A novel series of side-chain liquid crystalline copolysiloxanes containing [S]-1-(2-naphthyl ethyl 6-[4-(10-undecen-1-yloxy biphenyl--carbonyloxy]-2-naphthoate mesogenic and 4-biphenyl -allyloxybenzoate mesogenic side groups in the backbone and side chains liquid crystalline copolymers were prepared and evaluated as possible stationary phases for gas chromatography capillary columns. All copolymers display enantiotropic cholesteric phases. These mesomorphic polysiloxanes specimens with the widest temperature range were used as the stationary phase in a gas chromatography capillary column, and it showed good thermal and physical stability, excellent chemical inertness, and unique separation properties for polycyclic aromatic compounds. These cholesteric LC copolysiloxane stationary phases show much better separation effect for the polycyclic aromatic compound than those of the nematic and smectic LC copolysiloxanes.

  16. Synthesis and Liquid Crystalline Properties of New Diols Containing Azomethine Groups

    Directory of Open Access Journals (Sweden)

    Issam Ahmed Mohammed

    2010-04-01

    Full Text Available A series of new mesogenic azomethine diols were successfully synthesized by condensation reactions between various chloroalkanols and N,N'-bis(4-hydroxy-benzylidene-o-toluidine (1. The structures of these compounds were confirmed by CHN, FT-IR, 1H-NMR, and 13C-NMR spectrophotometer. Their thermotropic liquid crystalline behavior was studied using differential scanning calorimetry (DSC and polarizing optical microscope (POM. 4,4'-di(4-Hydroxybutoxy-N-benzylidine-o-tolidine (2a does not exhibit liquid crystalline properties. A nematic texture was observed for mesogenic diols 2b, and 2d, whereas the diol 2c exhibits a smectic mesophase. The increase of terminal alkyl chain in these mesogenic diols leads to a decrease in the transition temperature.

  17. Light amplification by photorefractive ferroelectric liquid crystal blends containing quarter-thiophene photoconductive chiral dopant

    Science.gov (United States)

    Sasaki, T.; Hara, T.; Yamamoto, Y.; Naka, Y.; Le, K. V.

    2017-05-01

    The photorefractive effect is a phenomenon that forms a rewritable hologram in a material. This phenomenon can be utilized in devices including 3D displays, optical tomography, novelty filters, phase conjugate wave generators, and optical amplification. Ferroelectric liquid crystal blends composed of a smectic liquid crystalline mixture, a photoconductive chiral dopant, and an electron trap reagent exhibit significant photorefractivity together with rapid responses. As such, they allow the dynamic amplification of moving optical signals. The photoconductive chiral dopants used in the previous study are ter-thiphene derivatives so that the photorefractive effect was examined at 488 nm. In the present work, chiral dopants possessing quarter-thiphene chromophore were synthesized and the photorefractive effect of the FLC blends at longer wavelength was demonstrated.

  18. Pengaruh Variasi Konsentrasi Pektin Kulit Buah Jeruk Bali (Citrus Maxima Merr.) Sebagai Suspending Agent Terhadap Sifat Fisik Suspensi Magnesium Hidroksida

    OpenAIRE

    windriyati, yulias ninik; kurnaningsih, ika; mufrod, mufrod

    2008-01-01

    Suspention is the most effective liquid dosage form for magnesium hydroxide because the compound relatively insoluble in water. Pectin as suspending agent has been used to inhibit sedimentation of suspension. The aim of this research is to know physical and chemical characteristic of pectin from Bali Citrus Peels and the influence of difference concentration of pectin and storage duration to physical characteristic of magnesium hydroxide suspensions. Pectin powder was extracted from Bali Citr...

  19. Simulation of suspended sediment transport initialized with satellite derived suspended sediment concentrations

    Science.gov (United States)

    Ramakrishnan, Ratheesh; Rajawat, A. S.

    2012-10-01

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are realized with respect to the sediment size distribution and the bottom bed materials observed in the Gulf. Simulated SSCs are compared with alternate OCM derived SSC. The results are observed to be impetus where the model is able to generate the spatial dynamics of the sediment concentrations. Sediment dynamics like deposition, erosion and dispersion are explained with the simulated tidal currents and OCM derived sediment concentrations. Tidal range is observed as the important physical factor controlling the deposition and resuspension of sediments within the Gulf. From the simulation studies; maximum residual current velocities, tidal fronts and high turbulent zones are found to characterise the islands and shoals within the Gulf, which results in high sediment concentrations in those regions. Remarkable variability in the bathymetry of the Gulf, different bed materials and varying tidal conditions induces several circulation patterns and turbulence creating the unique suspended sediment concentration pattern in the Gulf.

  20. A suspended sediment yield predictive equation for river basins in ...

    African Journals Online (AJOL)

    An empirical equation that can be used for estimating the suspended sediment yields of river drainage basins without sediment data has been established for basins in the sub-tropical forest Southwestern river basin system of Ghana. The power law equation relates mean annual specific suspended sediment yield (t km-2 ...

  1. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud. Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  2. Energy values of suspended detritus in Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Royan, J.P.; Sumitra-Vijayaraghavan

    Energy content of suspended detritus was determined in Andaman Sea waters during April-May 1988. The caloric content of suspended detritus ranged from 987 to 7040 cal. per gram dry wt with an average value of 5530 cal. per gram dry wt. The results...

  3. A wave-resolving model for nearshore suspended sediment transport

    Science.gov (United States)

    Ma, Gangfeng; Chou, Yi-Ju; Shi, Fengyan

    2014-05-01

    This paper presents a wave-resolving sediment transport model, which is capable of simulating sediment suspension in the field-scale surf zone. The surf zone hydrodynamics is modeled by the non-hydrostatic model NHWAVE (Ma et al., 2012). The turbulent flow and suspended sediment are simulated in a coupled manner. Three effects of suspended sediment on turbulent flow field are considered: (1) baroclinic forcing effect; (2) turbulence damping effect and (3) bottom boundary layer effect. Through the validation with the laboratory measurements of suspended sediment under nonbreaking skewed waves and surfzone breaking waves, we demonstrate that the model can reasonably predict wave-averaged sediment profiles. The model is then utilized to simulate a rip current field experiment (RCEX) and nearshore suspended sediment transport. The offshore sediment transport by rip currents is captured by the model. The effects of suspended sediment on self-suspension are also investigated. The turbulence damping and bottom boundary layer effects are significant on sediment suspension. The suspended sediment creates a stably stratified water column, damping fluid turbulence and reducing turbulent diffusivity. The suspension of sediment also produces a stably stratified bottom boundary layer. Thus, the drag coefficient and bottom shear stress are reduced, causing less sediment pickup from the bottom. The cross-shore suspended sediment flux is analyzed as well. The mean Eulerian suspended sediment flux is shoreward outside the surf zone, while it is seaward in the surf zone.

  4. Evaluation of the suspending properties of Cola acuminata gum on ...

    African Journals Online (AJOL)

    Many natural gums are employed as suspending agents in the formulation of pharmaceutical suspensions. The search to develop locally available natural gum from apparently a waste product as an alternative suspending agent stimulated the interest in this present study. Cola acuminata gum (CAG) extracted from Cola ...

  5. 40 CFR 230.21 - Suspended particulates/turbidity.

    Science.gov (United States)

    2010-07-01

    ... time. These new levels may reduce light penetration and lower the rate of photosynthesis and the... suspended particulates persist. The biological and the chemical content of the suspended material may react with the dissolved oxygen in the water, which can result in oxygen depletion. Toxic metals and organics...

  6. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  7. Evaluation of the suspending property of grewia gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in sulphadimidine suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for sulphadimidine. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  8. Evaluation of the suspending properties of Adansonia digitata gum ...

    African Journals Online (AJOL)

    Sedimentation volume and rate, rheology, and ease of redispersion were employed as evaluation parameters. The results showed that both hot and cold water extracts of the gum used at 2-3 % w/v produced a better suspending property than 4 % w/v Compound Tragacanth gum. The suspending ability of the gums was in ...

  9. Evaluation of the Suspending Property of Grewia Gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in metronidazole suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for metronidazole. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  10. Synthesis and mesomorphic properties of new heterocyclic liquid crystals with Central Ester–Chalcone linkages

    Directory of Open Access Journals (Sweden)

    Yong-Wei Cheryl Lim

    2017-01-01

    Full Text Available A series of new calamitic liquid crystals, 4-[3-(pyridin-4-ylprop-2-enoyl]phenyl 4-alkyloxybenzoates, comprising a pyridyl core, ester–chalcone central linkage and terminal alkyloxy chain were synthesized and characterized. This series consists of four members that differ by the length of the alkyloxy chain (CnH2n+1O, where n = 10, 12, 14, 16. The structures of the title compounds were elucidated using spectroscopic and spectrometric techniques, such as FT-IR, NMR (1H and 13C and EI-MS. The mesomorphic properties were studied using differential scanning calorimetry and optical polarizing microscopy. The decyloxy-containing compound was found to be non-mesogenic, whilst the compounds containing n-dodecyloxy to n-hexadecyloxy chains exhibited an enantiotropic smectic A phase with a fan-shaped texture. From the structure–property relationship study, it was proposed that the number of carbons in the alkyloxy chain must be at least 12 (n ≥ 12 to generate the smectic phase in the corresponding substituted ArCOOArCOCHCHC5H4N compounds.

  11. Synthesis of Biocompatible Liquid Crystal Elastomer Foams as Cell Scaffolds for 3D Spatial Cell Cultures.

    Science.gov (United States)

    Prévôt, Marianne E; Ustunel, Senay; Bergquist, Leah E; Cukelj, Richard; Gao, Yunxiang; Mori, Taizo; Pauline, Lindsay; Clements, Robert J; Hegmann, Elda

    2017-04-11

    Here, we present a step-by-step preparation of a 3D, biodegradable, foam-like cell scaffold. These scaffolds were prepared by cross-linking star block co-polymers featuring cholesterol units as side-chain pendant groups, resulting in smectic-A (SmA) liquid crystal elastomers (LCEs). Foam-like scaffolds, prepared using metal templates, feature interconnected microchannels, making them suitable as 3D cell culture scaffolds. The combined properties of the regular structure of the metal foam and of the elastomer result in a 3D cell scaffold that promotes not only higher cell proliferation compared to conventional porous templated films, but also better management of mass transport (i.e., nutrients, gases, waste, etc.). The nature of the metal template allows for the easy manipulation of foam shapes (i.e., rolls or films) and for the preparation of scaffolds of different pore sizes for different cell studies while preserving the interconnected porous nature of the template. The etching process does not affect the chemistry of the elastomers, preserving their biocompatible and biodegradable nature. We show that these smectic LCEs, when grown for extensive time periods, enable the study of clinically relevant and complex tissue constructs while promoting the growth and proliferation of cells.

  12. Molecular dynamics simulations of liquid crystals at interfaces

    CERN Document Server

    Shield, M

    2002-01-01

    Molecular dynamics simulations of an atomistic model of 4-n-octyl-4'-cyanobiphenyl (8CB) were performed for thin films of 8CB on solid substrates (a pseudopotential representation of the molecular topography of the (100) crystal surface of polyethylene (PE), a highly ordered atomistic model of a pseudo-crystalline PE surface and an atomistic model of a partially orientated film of PE), free standing thin films of 8CB and 8CB droplets in a hexagonal pit. The systems showed strong homeotropic anchoring at the free volume interface and planar anchoring at the solid interface whose strength was dependent upon the surface present. The free volume interface also demonstrated weak signs of smectic wetting of the bulk. Simulations of thin free standing films of liquid crystals showed the ordered nature of the liquid crystals at the two free volume interfaces can be adopted by the region of liquid crystal molecules between the homeotropic layer at each interface only if there is a certain number of liquid crystal mole...

  13. Emulsifying and suspending properties of cashew gum ...

    African Journals Online (AJOL)

    Emulsifying abilities of CG were juxtaposed with those of established AG and both gums were found to produce emulsions of liquid paraffin with varying stabilities. At 10%w/v emulsifier concentration, emulsions made with CG creamed within 24 hours of formulation but at 20%w/v, the emulsion remained stable throughout ...

  14. Structure-property relations in siloxane-based main chain liquid crystalline elastomers and related linear polymers

    Science.gov (United States)

    Ren, Wanting

    2007-12-01

    Soft materials have attracted much scientific and technical interest in recent years. In this thesis, attention has been placed on the underpinning relations between molecular structure and properties of one type of soft matter---main chain liquid crystalline elastomers (MCLCEs), which may have application as shape memory or as auxetic materials. In this work, a number of siloxane-based MCLCEs and their linear polymer analogues (MCLCEs) with chemical variations were synthesized and examined. Among these chemical variations, rigid p-phenylene transverse rod and flat-shaped anthraquinone (AQ) mesogenic monomers were specifically incorporated. Thermal and X-ray analysis found a smectic C phase in most of our MCLCEs, which was induced by the strong self-segregation of siloxane spacers, hydrocarbon spacers and mesogenic rods. The smectic C mesophase of the parent LCE was not grossly affected by terphenyl transverse rods. Mechanical studies of MCLCEs indicated the typical three-region stress-strain curve and a polydomain-to-monodomain transition. Strain recovery experiments of MCLCEs showed a significant dependence of strain retentions on the initial strains but not on the chemical variations, such as the crosslinker content and the lateral substituents on mesogenic rods. The MCLCE with p-phenylene transverse rod showed a highly ordered smectic A mesophase at room temperature with high stiffness. Mechanical properties of MCLCEs with AQ monomers exhibit a strong dependence on the specific combination of hydrocarbon spacer and siloxane spacer, which also strongly affect the formation of pi-pi stacking between AQ units. Poisson's ratio measurement over a wide strain range found distinct trends of Poisson's ratio as a function of the crosslinker content as well as terphenyl transverse rod loadings in its parent MCLCEs.

  15. Microchip systems for imaging liquid and high temperature processes in TEM & SEM

    DEFF Research Database (Denmark)

    Jensen, Eric; Canepa, Silvia; Møller-Nilsen, Rolf Erling Robberstad

    2014-01-01

    measurementson high temperature fuel cell systems. For imaging processes in liquids, our SEM system enables imaging on-chip microelectrodes andusing standard built-in reference electrodes [2]. To get higher resolution in TEM, we have createda monolithic chip system with suspended microfabricated channels [3......]. Both systems will allowhigh resolution imaging of heterogeneous electrochemical processes such as those in batteries.Based on the suspended microfluidic channels, we are also developing microchips that enableultrafast freezing of processes in liquids....

  16. Quantized layer growth at liquid-crystal surfaces

    DEFF Research Database (Denmark)

    Ocko, B. M.; Braslau, A.; Pershan, P. S.

    1986-01-01

    The authors report X-ray reflectivity measurements on the free surface of dodecylcyanobiphenyl (12CB) at the isotropic to smectic-A phase transition. At about 10°C above TIA, smectic-A-like ordering develops at the surface while the bulk phase remains isotropic. The angular dependence of the spec...

  17. Influence of charge carriers on corrugation of suspended graphene

    Science.gov (United States)

    Kirilenko, Demid A.; Gorodetsky, Andrei; Baidakova, Marina V.

    2018-02-01

    Electronic degrees of freedom are predicted to play a significant role in mechanics of two-dimensional crystalline membranes. Here we show that appearance of charge carriers may cause a considerable impact on suspended graphene corrugation, thus leading to additional mechanism resulting in charge carriers mobility variation with their density. This finding may account for some details of suspended graphene conductivity dependence on its doping level and suggests that proper modeling of suspended graphene-based device properties must include the influence of charge carriers on its surface corrugation.

  18. Synthesis and Characterization of Ferroelectric Liquid Crystalline Organosiloxanes Containing 4-(4-undecanyloxy bi-phenyl-1-carboxyloxyphenyl (2S,3S-2-chloro-3-methylvalerate and 4-(4-undecanyloxybenzoyloxybiphenyl (2S,3S-2-chloro-3-methylvalerate

    Directory of Open Access Journals (Sweden)

    Chih-Hung Lin

    2013-10-01

    Full Text Available A series of new organosiloxane ferroelectric liquid crystalline (FLC materials have been synthesized, and their mesomorphic and physical properties have been characterized. Four new disiloxanes and trisiloxanes, containing biphenyl 4-hydroxybenzoate and phenyl 4-hydroxybiphenylcarboxylate as mesogenic units and eleven methylene unit as spacers and (2S,3S-2-chloro-3-methylvalerate unit as chiral end groups. The molecule, using three phenyl ring as a mesogenic unit, formulates much wider liquid crystalline phase temperature ranges than that of a two phenyl ring unit. The phenyl arrangement differences of mesogenic unit result in the greater differences of the liquid crystal phase formation. The siloxane molecule induction is helpful to the more regular smectic phase formation and smectic phase stabilization, such as chiral SC (SC* and SB phases. The siloxane molecule is helpful to reduce the phase transition temperature and broaden the liquid crystal temperature range of the SC* phase and, simultaneously, it will not induce chain crystallization phenomenon and dilute the Ps value. The synthesis and characterization of the new FLCs materials, which exhibit a room temperature SC* phase and higher spontaneous polarization are presented.

  19. Introduction to suspended-sediment sampling

    Science.gov (United States)

    Nolan, K. Michael; Gray, John R.; Glysson, G. Douglas

    2005-01-01

    Knowledge of the amount and timing of sediment transport in streams is important to those directly or indirectly responsible for developing and managing water and land resources. Such data are often used to judge the health of watershed and the success or failure of activities designed to mitigate adverse impacts of sediment on streams and stream habitats. This training class presents an introduction to methods currently used by the U.S. Geological Survey (USGS) to sample suspended-sediment concentrations in streams. The presentation is narrated, but you control the pace of the presentation. If the computer you are using can view 'MPEG' videos you will be able to take advantage of videos interspersed in the presentation. A test, found at the end of the presentation, can be taken to assess how well you understood the training material. The class, which is registered as class SW4416 with the National Training Center of the USGS, should take two or three hours to complete. In order to use the presentation provided via this Web page, you will need to download a large disc images (linked below) and 'burn' it to a blank CD-ROM using a CD-ROM recorder on your computer. The presentation will only run on a Windows-based personal computer (PC). The presentation was developed using Macromedia Director MX 20041 and is contained in the file 'SIR05-5077.exe' which should autolaunch. If it does not, the presentation can be started by double-clicking on the file name. A sound card and speakers are necessary to take advantage of narrations that accompany the presentation. Text of narrations is provided, if you are unable to listen to narrations. Instructions for installing and running the presentation are included in the file 'Tutorial.htm', which is on the CD. 1 Registered Trademark: Macromedia Incorporated

  20. Investigation of thermal and optical properties of some quartet mixed hydrogen-bonded liquid crystals

    Science.gov (United States)

    Okumuş, Mustafa

    2017-11-01

    In this study, the thermal and optical properties of quartet mixtures formed at different weight ratios (1:1:1:1 and 1.5:1:1:1) from liquid crystals 4-octyloxy-4‧-cyanobiphenyl (8OCB), 4-hexylbenzoic acid, 4-(octyloxy)benzoic acid and 4-(decyloxy)benzoic acid were investigated by differential scanning calorimeter (DSC) and polarized optic microscopy (POM). The phase transition temperatures of the novel quartet mixtures measured in the DSC experiments are in line with the POM experiments. The experimental results clearly show that the novel liquid crystal mixtures have displayed pure liquid crystalline properties. According to the phase diagram drawn from DSC results, the nematic range of the novel mixture at the eutectic point is larger than the nematic ranges of the components. The mesomorphic structures of produced homolog complex mixtures are found to be smectic and nematic phases. But the smectic phase cannot be observed in the novel complex 1.5:1:1:1 mixture during continuous cooling. The nematic range of the novel complex 1.5:1:1:1 mixture is bigger than the nematic range of the novel complex 1:1:1:1 mixture with increasing 8OCB. Also, the nematic-to-isotropic phase transition temperature decreases with increasing the weight ratio of 8OCB in the complex quartet mixture. Another interesting result is that the produced mixtures are to be like a medical cream at room temperatures. Furthermore, order parameter and thermal stability factor of the transitions are also calculated.

  1. Liquid crystal interfaces: Experiments, simulations and biosensors

    Science.gov (United States)

    Popov, Piotr

    hydrocarbon surfaces at the atomic level. I show that the vertical alignment of a rod-like liquid crystal molecule first requires its insertion into the alignment layer. In CHAPTER 4, I investigate the Brownian behavior of a tracer molecule at an oil/water interface and explain the experimentally-observed anomaly of its increased mobility. Following my molecular dynamics simulation studies of liquid interfaces, I continue my work in CHAPTER 5 with experimental research. I employ the high sensitivity of liquid crystal alignment to the presence of amphiphiles adsorbed to the liquid crystal surface from water for potential biosensor applications. I propose a more accurate method of sensing using circular polarization and spectrophotometry. In CHAPTER 6, I investigate if cholesteric and smectic liquid crystals can potentially offer new modes of biosensing. In CHAPTER 7, I describe preliminary results toward constructing a liquid crystal biosensor platform with capabilities of specific sensitivity using proteins and antibodies. Finally in CHAPTER 8, I summarize the findings of my studies and research and suggest possible future experiments to further advance our knowledge in interfacial science for future applications.

  2. 3D quantum liquid crystals by condensation of dislocation worldsheets

    Science.gov (United States)

    Beekman, Aron; Wu, Kai; Nissinen, Jaakko; Zaanen, Jan

    A solid can partially melt into a liquid crystal where rotational rigidity is maintained while translational symmetry is restored. The topological melting is caused by an unbinding of dislocations. We recently provided a comprehensive review of quantum dislocation-mediated melting in 2D (arXiv:1603.04254). Through a duality mapping, phonons turn into dual gauge fields mediating interactions between dislocations. Upon condensation of dislocations, the dual gauge fields undergo the Anderson-Higgs mechanism and become gapped, signaling the loss of shear rigidity. Here we extend this theory to three dimensions. Dislocations are now linelike objects, strings, tracing out worldsheets in spacetime, while the dual gauge-fields become two-form (Kalb-Ramond) fields. We obtain the Higgs phase of these two-form gauge fields. Translational symmetry can be restored in three, two or one directions leading to nematic, smectic or columnar quantum liquid crystals. We derive the spectrum of low-energy excitations and its linear response. Goldstone modes due to broken rotational symmetry as well as superconductivity emerge whenever translational symmetry is restored. The peculiar features of liquid-crystalline order can be probed by finite-momentum spectroscopy.

  3. Ratios of total suspended solids to suspended sediment concentrations by particle size

    Science.gov (United States)

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  4. Suspended sediment concentration profiles from synoptic satellite observations

    Digital Repository Service at National Institute of Oceanography (India)

    Ramakrishnan, R.; Rajawat, A; Chauhan, O.S.

    A method is developed to estimate vertical suspended sediment concentration (SSC) profiles in Gulf of Kachchh, from the sediment concentration values derived from synoptic observations of Ocean Colour Monitor (OCM). Under the influence of currents...

  5. Monosaccharide composition of suspended particles from the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Sankaran, P.D.; Wagh, A.B.

    Neutral carbohydrates were determined as alditol acetates by capillary gas chromatography in the hydrolysates of suspended particulate samples (40) collected from 8 depths (approx 1 to 1,000 m) at 5 stations of the Bay of Bengal. Eight individual...

  6. Particles matter: Transformation of suspended particles in constructed wetlands

    NARCIS (Netherlands)

    Mulling, B.T.M.

    2013-01-01

    This thesis shows that constructed wetlands transform suspended particles in (treated) municipal wastewater through selective precipitation in ponds, biological filtering by plankton communities and physical and biological retention in reed beds. These processes effectively remove faecal indicator

  7. Suspended-sediment and suspended-sand concentrations and loads for selected streams in the Mississippi River Basin, 1940-2009

    Science.gov (United States)

    Heimann, David C.; Cline, Teri L.; Glaspie, Lori M.

    2011-01-01

    This report presents suspended-sediment concentration and streamflow data, describes load-estimation techniques used in the computation of annual suspended-sediment loads, and presents annual suspended-sediment loads for 48 streamgaging stations within the Mississippi River Basin. Available published, unpublished, and computed annual total suspended-sediment and suspended-sand loads are presented for water years 1940 through 2009. When previously published annual loads were not available, total suspended-sediment and sand loads were computed using available data for water years 1949 through 2009. A table of suspended-sediment concentration and daily mean streamflow data used in the computation of annual loads is presented along with a table of compiled and computed annual suspended-sediment and suspended-sand loads, annual streamflows, and flow-weighted concentrations for the 48 stations.

  8. Suspended sediment apportionment in a South-Korean mountain catchment

    Science.gov (United States)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  9. New developments in 3D liquid crystal elastomers scaffolds for tissue engineering: from physical template to responsive substrate

    Science.gov (United States)

    Prévôt, Marianne E.; Bergquist, Leah E.; Sharma, Anshul; Mori, Taizo; Gao, Yungxiang; Bera, Tanmay; Zhu, Chenhui; Leslie, Michelle T.; Cukelj, Richard; Korley, LaShanda T. J.; Freeman, Ernest J.; McDonough, Jennifer A.; Clements, Robert J.; Hegmann, Elda

    2017-08-01

    We report here on cell growth and proliferation within a 3D architecture created using smectic liquid crystal elastomers (LCEs) leading to a responsive scaffold for tissue engineering. The investigated LCE scaffolds exhibit biocompatibility, controlled degradability, with mechanical properties and morphologies that can match development of the extracellular matrix. Moreover, the synthetic pathway and scaffold design offer a versatility of processing, allowing modifications of the surface such as adjusting the hydrophilic/hydrophobic balance and the mobility of the LC moieties to enhance the biomaterial performance. First, we succeeded in generating LCEs whose mechanical properties mimic muscle tissue. In films, our LCEs showed cell adhesion, proliferation, and alignment. We also achieved creating 3D LCE structures using either metallic template or microsphere scaffolds. Finally, we recorded a four times higher cell proliferation capability in comparison to conventional porous films and, most importantly, anisotropic cell growth that highlights the tremendous effect of liquid crystal moieties within LCEs on the cell environment.

  10. Turbulence control of suspended matter aggregate size

    Science.gov (United States)

    Jago, C. F.; Jones, S. E.; Rippeth, T. P.; Simpson, J. H.

    2003-04-01

    The size and properties of the aggregates which comprise suspended particulate matter (SPM) change on short time and length scales in shelf seas. There is experimental and theoretical evidence to suggest that turbulence plays a key role in aggregation but there is contradictory evidence with respect to disaggregation: it has been proposed that sinking stresses, rather than turbulent stresses, are the dominant control of disaggregation. But there is little observational evidence for turbulence control of particle properties. New observations are presented which provide compelling evidence for turbulence control of both aggregation and disaggregation. TKE dissipation and particle size were measured in situ at stratified sites in the northern North Sea in 110 m water depth during the period of weakening of the seasonal thermocline (in October/November) and in the Clyde Sea in 55 m water depth (April). There were similar vertical distributions of TKE dissipation E, SPM concentration C, and particle size D at both sites. At the base of the thermocline, there were minima in E and C, but a maximum in D, indicating that enhanced aggregation was occurring in this region of low turbulent stress. In the bottom mixed layer, E and C increased, while D decreased due to disaggregation in this region of increasing turbulent stress towards the seabed. Particles settling out of the low stress region at the base of the thermocline began to disaggregate when E increased to 3.2x10-6 watts m-2. D did not correlate directly with E because aggregation is a function of collision frequency (and hence of both C and E): this can be accounted for using a simplified theoretical aggregation model which treats flocs as self-similar fractal entities and allows simultaneous floc formation and break up, specified as functions of C and E. It was found that in the northern North Sea the measured D represents an equilibrium size predicted by the model, while in the Clyde Sea tidal variation in both C

  11. The determination of the phase transition temperatures of a semifluorinated liquid crystalline biphenyl ester by impedance spectroscopy as an alternative method

    Energy Technology Data Exchange (ETDEWEB)

    Yıldız, Alptekin [Istanbul Technical University, Department of Physics Engineering, Maslak, 34469 Istanbul (Turkey); Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Canli, Nimet Yilmaz, E-mail: niyilmaz@yahoo.com [Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Karanlık, Gürkan; Ocak, Hale [Yildiz Technical University, Department of Chemistry, 34220 Istanbul (Turkey); Okutan, Mustafa [Yildiz Technical University, Department of Physics, 34220 Istanbul (Turkey); Eran, Belkız Bilgin [Yildiz Technical University, Department of Chemistry, 34220 Istanbul (Turkey)

    2016-12-15

    Dielectric spectroscopy (DS) is a very powerful and important for better understanding of the molecular dynamics and relaxation phenomena in liquid crystals. The dielectric and impedance characteristics Ethyl 4-(7,7,8,8,9,9,10,10,10-nonafluorodecyloxy)biphenyl-4′-carboxylate (ENBC) liquid crystal have been analyzed over the frequency range of 100 Hz to MHz in the temperature region from room temperature to 180 °C. The compound ENBC shows enantiotropic a smectic mesophase in a wide temperature range. The phase transition temperatures T (°C) of the liquid crystal ENBC, which were characterized by Differential Scanning Calorimetry (DSC), have been verified by the dielectric measurements and conductivity mechanisms of the ENBC. The activation energies for some selected angular frequencies have also been calculated.

  12. Chiral liquid-crystalline polyacrylates from (S-(--2-methyl-1-butanol. Synthesis, mesomorphic properties and light scattering

    Directory of Open Access Journals (Sweden)

    Merlo Aloir A.

    2001-01-01

    Full Text Available The synthesis and mesomorphic behavior of two chiral side chain liquid crystalline polyacrylates from (S-(--2-methyl-1-butanol are described. These new polyacrylates show a dependence of the phase transition temperatures on both, molecular weight and spacer length. The polyacrylate with four methylene units in the spacer exhibits a chiral nematic phase whereas the polyacrylate with a spacer containing eleven methylene units presents a smectic phase. In addition, the chiral nematic phase appears for low molecular weight and smectic phase for high molecular weight polyacrylates. Light scattering experiments were performed in dilute solutions of the polyacrylate containing eleven methylene units in tetrahydrofuran and dichloromethane. Values for weight averaged molecular weight, radius of gyration and second virial coefficient were determined by static light scattering whereas the diffusion coefficient and the hydrodynamic radius of the chains were obtained by photon correlation spectroscopy. A comparison between both techniques indicates that the chain behavior can be taken as typical for a polydisperse linear chain in a good solvent.

  13. Study of order and dynamics in liquid crystalline materials by carbon-13 and deuterium NMR spectroscopy

    Science.gov (United States)

    Xu, Jiadi

    This dissertation investigates the phase structures, molecular structures and diffusion motions in some recently discovered liquid crystals using 1D and 2D carbon-13 and deuterium NMR spectroscopy. Two classes of liquid crystals are involved: chiral rod-like liquid crystals and banana mesogens. Our investigations of these new materials were divided into five main sections. The ordering and structures of banana liquid crystals and chiral rod-like mesogens were extracted from solid-state 13C NMR experiments including Separated-Local-Field study based on Lee-Goldberg Cross-Polarization (LGCP-SLF) and temperature dependent chemical shifts. The principal values of CSA tensor were measured using Separation of Undistorted CSA Powder patterns by Effortless Recoupling (SUPER) experiment. Some ID and 2D pulse experiments were performed for the assignment of carbon peaks, such as Cross-Polarization Polarization-Inversion (CPPI), HECTOR and so on. The soliton-like distortion of the helicoidal structure in the chiral smectic C phase (SmC*) of 8BEF5 liquid crystal was observed by the angular dependent DNMR patterns, and quantitatively interpreted based on Landau theory. The distortion was induced by the NMR magnetic field. The phase structure and interlayer diffusion in anticlinic Sm C* phases (Sm C*A , Sm C*Fi1 and Sm C*Fi2 ) of 10B1M7 liquid crystal were measured using angular dependent DNMR lineshapes and echo intensities. This work represents the first study of ferrielectric smectic phases by means of NMR. Measurements of the interlayer diffusion in synclinic and anticlinic SmC* phases (SmC*, Sm C*Fi1 and Sm C*Fi2 ) of 10B1M7 were carried out using 2H NMR exchange experiments. The phase structures of anticlinic SmC* phases were also determined using the same technique. A 'deformed clock model' was found to be appropriate for these phases. Molecular structures and dynamics were investigated in an exotic B 2 phase of a banana liquid crystal Pbis11BB by means of CP-MAS 13C NMR

  14. Study on submerged anaerobic membrane bioreactor (SAMBR) treating high suspended solids raw tannery wastewater for biogas production.

    Science.gov (United States)

    Umaiyakunjaram, R; Shanmugam, P

    2016-09-01

    This study deals with the treatment of high suspended solids raw tannery wastewater using flat sheet Submerged Anaerobic Membrane (0.4μm) Bioreactor (SAMBR) acclimatized with hypersaline anaerobic seed sludge for recovering biogas. The treatability of SAMBR achieved higher CODremoval efficiency (90%) and biogas yield (0.160L.g(-1) CODremoved) coincided with high r(2) values between permeate flux and TSS (0.95), biogas and COD removed (0.96). The acidification of hypersaline influent wastewater by biogas mixing with high CO2, achieved quadruplet benefit of gas liquid and solid separation, in-situ pH and NH3 control, in-situ CH4 enrichment, and prevention of membrane fouling. The initial high VFA became stable as time elapsed reveals the hydrolysing ability of particulate COD into soluble COD and into biogas, confirms the suitability of SAMBR for high suspended solids tannery wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Liquid marble as microbioreactor for bioengineering applications

    Science.gov (United States)

    Sarvi, Fatemeh; Jain, Kanika; Alhasan, Layla; Arbatan, Tina; Shen, Wei; Chan, Peggy P. Y.

    2015-12-01

    This paper reports the use of liquid marbles (LMs) as miniature bioreactors to produce three-dimensional (3D) spheroids including tumor-like spheriods from cancer cells and embryoid bodies (EBs) from stem cells. A liquid marble microbioreactor is prepared by placing a drop of cell suspension onto a polytetrafluoroethylene (PTFE) particle bed. Without the addition of growth factors, suspended EBs from liquid marbles exhibit spontaneous contraction. These results indicate that the liquid marble provides a suitable microenvironment to induce EB formation and spontaneous cardiac differentiation. The EBs were further plated onto gelatin-coated tissue culture dishes. Plated EBs express mature cardiomyocyte marker cardiac troponinT (cTnT), indicating that these EBs have differentiated into functional cardiomyocytes. The cardiomyocytes generated using this liquid marble approach could be useful for transplantation.

  16. Fermi liquids and Luttinger liquids

    OpenAIRE

    Schulz, H. J.; Cuniberti, G.; Pieri, P.

    1998-01-01

    In these lecture notes, the basic physics of Fermi liquids and Luttinger liquids is presented. Fermi liquids are discussed both from a phenomenological viewpoint, in relation to microscopic approaches, and as renormalization group fixed points. Luttinger liquids are introduced using the bosonization formalism, and their essential differences with Fermi liquids are pointed out. Applications to transport effects, the effect of disorder, quantum spin chains, and spin ladders, both insulating and...

  17. Temperature signal in suspended sediment export from an Alpine catchment

    Science.gov (United States)

    Costa, Anna; Molnar, Peter; Stutenbecker, Laura; Bakker, Maarten; Silva, Tiago A.; Schlunegger, Fritz; Lane, Stuart N.; Loizeau, Jean-Luc; Girardclos, Stéphanie

    2018-01-01

    Suspended sediment export from large Alpine catchments ( > 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation-deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through

  18. An electro-optic experimental study of an unusual liquid crystal phase transition

    Science.gov (United States)

    Staines, Daniel; Wicks, Derek; Havens, Austin; Fernsler, Jonathan

    2009-11-01

    Liquid crystal phases are highly sensitive to their surroundings and they interact with light in unusual ways: the index of refraction is different depending on the polarization of the incident light. This combination of properties makes them ideal for low-power liquid crystal displays (LCD's), ubiquitous in today's portable electronic devices. They are also beautiful: optical textures of liquid crystals show bright colors, with the color corresponding to the amount of retardation in the light polarized along different axes. These phases are fluid, but can nevertheless be highly ordered. We have developed a novel experimental analysis using a photometric calculation of microscopy images to perform a series of experiments on several liquid crystal materials, called ``de Vries'' smectics. Using this system, we examined how the structure of these phases changed under the influence of different boundary conditions, temperature, and applied electric fields. These unusual materials show the bizarre behavior of appearing to become less ordered with decreasing temperature. This phase, which is not fully understood, has advantageous optical properties that could lead to the next generation of liquid crystal displays.

  19. The rheology of non-suspended sediment transport mediated by a Newtonian fluid

    Science.gov (United States)

    Pähtz, Thomas; Durán, Orencio

    2017-04-01

    Using a coupled DEM/RANS numerical model of non-suspended sediment transport in a Newtonian fluid (Durán et al., POF 103306, 2012), we find that the gas-like part of the granular transport flow can be described by a universal condition that constrains the average geometry of interparticle collisions. We show that this condition corresponds to a constant sliding friction coefficient μ at an appropriately defined bed surface, thus explaining the success of Bagnold's old idea to describe the sediment transport in analogy to sliding friction. We are currently exploring whether this rheology applies to gas-like granular flows in general. We further find a transition of the gas-like flow to either a solid-like flow (solid-to-gas transition), which is typical for aeolian sediment transport ('saltation'), or a liquid-like flow (liquid-to-gas transition), which is typical for subaqueous sediment transport ('bedload'). The transition occurs at about the location of maximal particle collision frequency. If there is a liquid-like flow below the transition, we find that it can be described by a μ(I) rheology, where I is the visco-intertial number, an appropriately defined average of the viscous and intertial number.

  20. Hydrodynamic and suspended sediment transport controls on river mouth morphology

    Science.gov (United States)

    Falcini, F.; Piliouras, A.; Garra, R.; Guerin, A.; Jerolmack, D. J.; Rowland, J.; Paola, C.

    2014-01-01

    mouths building into standing bodies of water have strikingly varied growth habits. This presents a compelling pattern formation problem that is also of great practical relevance for subsurface prediction and managing coastal wetlands. Here we present a generalized 2.5-dimensional potential vorticity (PV) theory that explains sedimentation patterns of a sediment-laden stationary jet by coupling an understanding of vorticity with suspended sediment concentration fields. We explore the physical meaning of this new sediment-PV definition, and its impact on outflow depositional patterns, by analyzing data from a shallow wall-bounded plane jet experiment and by discussing new theoretical insights. A key result is that lateral advection and diffusion of suspended sediment are directly proportional to jet vorticity, a feature that reveals the mechanistic process that forms elongated channels by focused levee deposition. The new PV theory constitutes a more generalized mathematical framework that expands the Rouse theory for the equilibrium of suspended sediment.

  1. Extension of a suspended soap film: a homogeneous dilatation followed by new film extraction.

    Science.gov (United States)

    Seiwert, Jacopo; Monloubou, Martin; Dollet, Benjamin; Cantat, Isabelle

    2013-08-30

    Liquid foams are widely used in industry for their high effective viscosity, whose local origin is still unclear. This Letter presents new results on the extension of a suspended soap film, in a configuration mimicking the elementary deformation occurring during foam shearing. We evidence a surprising two-step evolution: the film first extends homogeneously, then its extension stops, and a new thicker film is extracted from the meniscus. The second step is independent of the nature of the surfactant solution, whereas the initial extension is only observed for surfactant solutions with negligible dilatational moduli. We predict this complex behavior using a model based on Frankel's theory and on interface rigidification induced by confinement.

  2. Dynamic transport of suspended sediment by solitary wave: Experimental study

    Science.gov (United States)

    cho, JaeNam; Kim, DongHyun; Hwang, KyuNam; Lee, SeungOh

    2016-04-01

    Solitary waves are able to transport a large amount of suspended sediment when approaching on the beach, which sometimes causes - serious beach erosion, especially in the east and south coastal lines in Korea. But it has rarely been known about the method how to evaluate or estimate the amount of beach erosion caused by solitary waves. Experimental assessment is necessary to comprehend the process of sediment transport on a slope. The prismatic rectangular channel is 12 m long, 0.8 m wide, and 0.75 m high. A sluice gate is applied at prismatic channel in order to produce the solitary waves. Upstream water depth is more than channel water depth and the sluice gate is suddenly opened to simulate conditions of solitary waves. A sand slope with a 1/6 and a sediment thickness is 0.03 m. The experimental sediments are used anthracite (d_50=1.547 mm ,C_u=1.38) and Jumoonjin sand (d_50=0.627 mm ,C_u=1.68). Specific laboratory equipment are designed to collect suspended sediment samples at the same time along the wave propagation at 5 points with evenly space. Each amount of sampling is approximately 25 ml and they are completely dried in oven over 24 hours according to the USGS (Guideline and standard techniques and method 3-C4). Two video cameras (Model No. : Sony, HDR-XR550) are mounted for capturing images at top and side-view when the processes of solitary wave and run up/down on slope. Also, this study are analyzed the correlation between Suspended sediment concentration and turbidity. Also, this study are analyzed the correlation between suspended sediment concentration and turbidity. Turbidity is used to verify suspended sediment concentration. Dimensionless analyses of experimental results carried out in this study. One dimensionless parameter is expressed with pressure of solitary wave on a slope to suspended sediment concentration, which is concerned about lifting force. The other is relate to drag force presenting with run up/down velocity on a slope and

  3. Design of a LC-tuned magnetically suspended rotating gyroscope

    Science.gov (United States)

    Jin, Lichuan; Zhang, Huaiwu; Zhong, Zhiyong

    2011-04-01

    A inductor-capacitor (LC) tuned magnetically suspended rotating gyroscope prototype is designed and analyzed. High permeability ferrite cores are used for providing suspension force, and the rotation system is designed using the switched reluctance motor (SRM) principle. According to the LC-tuned principle, magnetic suspension force expression has been derived. The electromagnetic properties of the gyroscope are simulated by the Ansoft Maxwell software. And our result is expected to be able to serve as a prototype of micro-electromechanical system (MEMS) magnetically suspended rotating gyroscope in future practical applications.

  4. Quantum Hall effect in multi-terminal suspended graphene devices

    Science.gov (United States)

    Ghahari, Fereshte; Zhao, Yue; Bolotin, Kirill; Kim, Philip

    2010-03-01

    The integer and fractional quantum hall effects have been already observed in two terminal suspended graphene devices. However in this two probe device geometry, mixing between magnetoresistance ρxx and Hall resistance ρxy for incompletely developed quantum Hall states leads to substantial deviation of conductance plateaus values. In this talk, we present the experimental results from four terminal suspended graphene devices. The quality of quantum Hall effect will be discussed in muti-terminal device geometry in conjunction with the current-induced annealing process to improve the quality of graphene samples.

  5. Colorimetry Technique for Scalable Characterization of Suspended Graphene.

    Science.gov (United States)

    Cartamil-Bueno, Santiago J; Steeneken, Peter G; Centeno, Alba; Zurutuza, Amaia; van der Zant, Herre S J; Houri, Samer

    2016-11-09

    Previous statistical studies on the mechanical properties of chemical-vapor-deposited (CVD) suspended graphene membranes have been performed by means of measuring individual devices or with techniques that affect the material. Here, we present a colorimetry technique as a parallel, noninvasive, and affordable way of characterizing suspended graphene devices. We exploit Newton's rings interference patterns to study the deformation of a double-layer graphene drum 13.2 μm in diameter when a pressure step is applied. By studying the time evolution of the deformation, we find that filling the drum cavity with air is 2-5 times slower than when it is purged.

  6. Fluctuations and phase transitions in Larkin-Ovchinnikov liquid-crystal states of a population-imbalanced resonant Fermi gas

    Science.gov (United States)

    Radzihovsky, Leo

    2011-08-01

    Motivated by a realization of imbalanced Feshbach-resonant atomic Fermi gases, we formulate a low-energy theory of the Fulde-Ferrell and the Larkin-Ovchinnikov (LO) states and use it to analyze fluctuations, stability, and phase transitions in these enigmatic finite momentum-paired superfluids. Focusing on the unidirectional LO pair-density-wave state, which spontaneously breaks the continuous rotational and translational symmetries, we show that it is characterized by two Goldstone modes, corresponding to a superfluid phase and a smectic phonon. Because of the liquid-crystalline “softness” of the latter, at finite temperature the three-dimensional state is characterized by a vanishing LO order parameter, quasi-Bragg peaks in the structure and momentum distribution functions, and a “charge”-4, paired-Cooper-pairs, off-diagonal long-range order, with a superfluid-stiffness anisotropy that diverges near a transition into a nonsuperfluid state. In addition to conventional integer vortices and dislocations, the LO superfluid smectic exhibits composite half-integer vortex-dislocation defects. A proliferation of defects leads to a rich variety of descendant states, such as the charge-4 superfluid and Fermi-liquid nematics and topologically ordered nonsuperfluid states, that generically intervene between the LO state and the conventional superfluid and the polarized Fermi liquid at low and high imbalance, respectively. The fermionic sector of the LO gapless superconductor is also quite unique, exhibiting a Fermi surface of Bogoliubov quasiparticles associated with the Andreev band of states, localized on the array of the LO domain walls.

  7. An apparatus for the specific heat measurement of undercooled liquids

    Science.gov (United States)

    Ohsaka, K.; Gatewood, J. R.; Trinh, E. H.

    1991-01-01

    This paper describes a drop calorimeter with an electromagnetic levitator that was specifically built for enthalpy measurements of undercooled liquids, including high-melting-point metals. Design diagrams of this device and of a furnace for making a suspended drop are presented together with results of measurements on an aluminum sample.

  8. Drying of liquid food droplets : enzyme inactivation and multicomponent diffusion

    NARCIS (Netherlands)

    Meerdink, G.

    1993-01-01

    In this thesis the drying of liquid food droplets is studied from three different points of view: drying kinetics, enzyme inactivation and multicomponent diffusion. Mathematical models are developed and validated experimentally.

    Drying experiments are performed with suspended

  9. Spatial distribution of soil erosion and suspended sediment ...

    Indian Academy of Sciences (India)

    sediment transport rate for Chou-Shui river basin ... 5, Anzhong Road,. Tainan 70970, Taiwan. 4. Department of Hydraulics and Ocean Engineering, National Cheng-Kung University, No. 1,. University Road, Tainan ... surface runoff discharge, suspended sediment transport rate, quantity of soil erosion, and spatial distribu-.

  10. Calamine lotion: experimenting with a new suspending agent.

    Science.gov (United States)

    Al-Achi, A; Greenwood, R; Akin-Isijola, A; Bullard, J

    1999-01-01

    The use of a new suspending agent is investigated. Calamine lotion, USP contains bentonite magma as a suspending agent. In this study, bentonite magma was partially or completely replaced with a new suspending agent called tahini. Tahini is sesame paste composed of crushed sesame seeds in sesame oil. It is frequently used in middle eastern food as a thickening and suspending agent. Calamine lotion was prepared, generally, according to the USP method. The formula contained 40% v/v magma. Tahini was added instead of bentonite magma by replacing 100%, 99%, 90%, 75%, 50% and 25% of the magma. The sedimentation volume and the degree of flocculation were calculated for the resulting preparations. Rheological characteristics of bentonite- and tahini-containing lotions were also determined. Sedimentation volume showed 0.723 and 0.851 (p=0.05) for the lotions containing 100% bentonite and 100% tahini, respectively. The degree of flocculation was 2.00 and 2.35 (p=0.05) for the 100% bentonite and 100% tahini lotions, respectively. The rheograms of all the suspensions showed pseudoplastic flow. Overall, the use of tahini in calamine lotion has improved the physical stability of the formula.

  11. Turbulence Flow Characteristics of Suspended Sediments and its ...

    African Journals Online (AJOL)

    These are inturn integrated to give the hydraulic resistance law for sediment laden flow. The law of velocity distribution in open channel flow with suspended sediments was derived introducing Monin-Obukhov Length L . The distribution equation agrees well with the observation of velocity profile in the experiments.

  12. Microscopic characterisation of suspended graphene grown by chemical vapour deposition

    NARCIS (Netherlands)

    Bignardi, L.; Dorp, W.F. van; Gottardi, S.; Ivashenko, O.; Dudin, P.; Barinov, A.; de Hosson, J.T.M.; Stöhr, M.; Rudolf, P.

    2013-01-01

    We present a multi-technique characterisation of graphene grown by chemical vapour deposition (CVD) and thereafter transferred to and suspended on a grid for transmission electron microscopy (TEM). The properties of the electronic band structure are investigated by angle-resolved photoelectron

  13. Geochemistry of suspended and settling solids in two freshwater lakes.

    NARCIS (Netherlands)

    Koelmans, A.A.

    1998-01-01

    This study describes the 1987–1992 time variationof the bulk chemical composition, levels of heavymetals, arsenic, nitrogen and phosporous insuspended and settling solids in Lake Volkerak andLake Zoom (The Netherlands). Suspended and setlingsolids were collected with continuous flowcentrifuges and

  14. Comparison of Suspended Solid Separation in Advanced Storm Overflow Structures

    DEFF Research Database (Denmark)

    Larsen, Torben; Sørensen, Morten Steen

    1990-01-01

    This paper describes a laboratory investigation of the separation of suspended solids in a circular weir overflow and a vortex separator. The basic idea is to evaluate the efficiency of a vortical flow in the overflow chamber, and to compare these results with other overflow structures....

  15. Current-use insecticides, phosphates and suspended solids in the ...

    African Journals Online (AJOL)

    In Western Cape orchard areas, the last pesticide application of the growing season in summer takes place at the end of February. Pesticides, total phosphates and total suspended solids (TSS) were measured in the Lourens River at the beginning of April 1999 prior to the first rainfall of the rainy season and in the middle of ...

  16. Reduction in density of suspended - sediment - laden natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desa, E.; Desa, E.; Smith, D.; Peshwe, V.B.; VijayKumar, K.; Desa, J.A.E.

    to 0.4% - 4.5%) that of the density of the same water without suspended sediment. Teh values of peff in a given site differed from one tidal cycle to another (approx equal to 1.9%). These values varied slightly (less than 0.8%) from mid-tide to slack...

  17. Transport of suspended particles in turbulent open channel flows

    NARCIS (Netherlands)

    Breugem, W.A.

    2012-01-01

    Two experiments are performed in order to investigate suspended sediment transport in a turbulent open channel flow. The first experiment used particle image velocimetry (PIV) to measure the fluid velocity with a high spatial resolution, while particle tracking velocimetry (PTV) was used to measure

  18. Spatial Distribution of Suspended Particulate Matter in Mtwapa ...

    African Journals Online (AJOL)

    Surface water concentrations of inorganic nutrients and suspended particulate matter (SPM) components from Mtwapa and Shirazi creeks in Kenya were measured and compared. This was aimed at assessing the contribution of phytoplankton carbon, particulate organic carbon (POC) and detritus on the total SPM pool, and ...

  19. Nature of suspended particulate matter and concentrations of heavy ...

    African Journals Online (AJOL)

    The concentrations of metals in bottom sediment in the Tanzanian waters of Lake Victoria and the nature of suspended particulate matter (SPM) were analysed. The objective of the study was to compare levels of metals in sediment from different locations and to establish their sources. Metal concentrations were higher in ...

  20. Amino sugars in suspended particulate matter from the Bay of ...

    Indian Academy of Sciences (India)

    Amino sugars (AS)are important constituents of organic matter.However,very little is known about their cycling in marine waters.In this research,we assessed the distribution and cycling of these compounds in waters of the Bay of Bengal.For this purpose,samples of suspended particulate matter (SPM)were collected from 8 ...

  1. Stabilised suspending efficiency of Laponite XLG and sodium ...

    African Journals Online (AJOL)

    Charged drugs like Sulphamerazine may make pseudoplastic/plastic materials become Newtonian and loose their suspending power. In this study ... For this purpose, the rheograms of the systems were obtained by the use of a Haake rotoviscometer RV 12 utilizing a cup and rotor sensor system MV 1. In the absence of ...

  2. Spin Transport in High-Quality Suspended Graphene Devices

    NARCIS (Netherlands)

    Guimaraes, Marcos H. D.; Veligura, A.; Zomer, P. J.; Maassen, T.; Vera-Marun, I. J.; Tombros, N.; van Arees, B. J.; Wees, B.J. van

    We measure spin transport in high mobility suspended graphene (mu approximate to 10(5)cm(2)/(V s)), obtaining a (spin) diffusion coefficient of 0.1 m(2)/s and giving a lower bound on the spin relaxation time (tau(s) approximate to 150 ps) and spin relaxation length (lambda(s) = 4.7 mu m) for

  3. 40 CFR 52.330 - Control strategy: Total suspended particulates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Total suspended... PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.330 Control strategy..., the State must repromulgate Regulation No. 1 to satisfy reasonably available control technology...

  4. Evaluation of the suspending properties of Abizia zygia gum on ...

    African Journals Online (AJOL)

    Method: The suspending properties of Albizia zygia gum (family Mimosoideae) were evaluated comparatively with those of Compound Tragacanth, Acacia and Gelatin at concentration range of 0.5 – 4.0%w/v in Sulphadimidine suspension. Characterization tests were carried out on purified Albizia zygia gum. Sedimentation ...

  5. Discrete Dynamics of Nanoparticle Channelling in Suspended Graphene

    DEFF Research Database (Denmark)

    Booth, Tim; Pizzocchero, Filippo; Andersen, Henrik

    2011-01-01

    We have observed a previously undescribed stepwise oxidation of mono- and few layer suspended graphene by silver nanoparticles in situ at subnanometer scale in an environmental transmission electron microscope. Over the range of 600–850 K, we observe crystallographically oriented channelling...

  6. Method for separating biological cells. [suspended in aqueous polymer systems

    Science.gov (United States)

    Brooks, D. E. (Inventor)

    1980-01-01

    A method for separating biological cells by suspending a mixed cell population in a two-phase polymer system is described. The polymer system consists of droplet phases with different surface potentials for which the cell populations exhibit different affinities. The system is subjected to an electrostatic field of sufficient intensity to cause migration of the droplets with an attendant separation of cells.

  7. Opportunities Suspended: The Disparate Impact of Disciplinary Exclusion from School

    Science.gov (United States)

    Losen, Daniel J.; Gillespie, Jonathan

    2012-01-01

    Well over three million children, K-12, are estimated to have lost instructional "seat time" in 2009-2010 because they were suspended from school, often with no guarantee of adult supervision outside the school. That's about the number of children it would take to fill every seat in every major league baseball park and every NFL stadium…

  8. Investigation of suspended sediment transport using ultrasonic techniques

    DEFF Research Database (Denmark)

    Bjørnø, Irina; Jensen, Leif Bjørnø

    1994-01-01

    The results of the initial experimental studies involving the scattering of ultrasonic signals from canonical and non-canonical shaped suspended particles with known elastical qualities are reported. These results have formed the basis for the development of a numerical model for ultrasound...

  9. Microwave-induced nonequilibrium temperature in a suspended carbon nanotube

    NARCIS (Netherlands)

    Hortensius, H.L.; Öztürk, A.; Zeng, P.; Driessen, E.F.C.; Klapwijk, T.M.

    2012-01-01

    Antenna-coupled suspended single carbon nanotubes exposed to 108?GHz microwave radiation are shown to be selectively heated with respect to their metal contacts. This leads to an increase in the conductance as well as to the development of a power-dependent DC voltage. The increased conductance

  10. Scanning tunneling spectroscopy of suspended single-wall carbon nanotubes

    NARCIS (Netherlands)

    LeRoy, B.J.; Lemay, S.G.; Kong, J.; Dekker, C.

    2004-01-01

    We have performed low-temperature scanning tunneling microscopy measurements on single-wall carbon nanotubes that are freely suspended over a trench. The nanotubes were grown by chemical vapor deposition on a Pt substrate with predefined trenches etched into it. Atomic resolution was obtained on the

  11. Evaluation of the Suspending Properties of the Coprecipitate of ...

    African Journals Online (AJOL)

    The suspending ability of the different ratios was evaluated in magnesium trisilicate suspension, and compared with a suspension prepared with Compound Tragacanth Powder BP (CTP) as well as a commercially available magnesium trisilicate suspension (MTS). The parameters tested were sedimentation rate, flow rate, ...

  12. Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Anhøj, Thomas Aarøe; Caviglia, Claudia

    2017-01-01

    In this work we present an easy, fast, reliable and low cost microfabrication technique for fabricating suspended microstructures of epoxy based photoresistswith UV photolithography. Two different fabrication processes with epoxy based resins (SU-8 and mr-DWL) using UV exposures at wavelengths...

  13. An analysis of bedload and suspended load interactions

    Science.gov (United States)

    Recking, alain; Navratil, Oldrich

    2013-04-01

    Several approaches were used to develop suspension equations. It includes semi-theoretical equations based on the convection diffusion equation (Einstein 1950; Van Rijn 1984; Camenen and Larson 2008; Julien 2010), semi-empirical tools based on energy concept (Velikanov 1954; Bagnold 1966), empirical adjustments (Prosser and Rusttomji 2000). One essential characteristic of all these equations is that most of them were developed by considering continuity between bedload and suspended load, and that the partitioning between these two modes of transport evolves progressively with increasing shear stress, which is the case for fine bed materials. The use of these equations is thus likely to be welcome in estuaries or lowland sandy rivers, but may be questionable in gravel-bed rivers and headwater streams where the bed is usually structured vertically and fine sediments potentially contributing to suspension are stored under a poorly mobile surface armour comprising coarse sediments. Thus one question this work aimed to answer is does the presence of an armour at the bed surface influence suspended load? This was investigated through a large field data set comprising instantaneous measurements of both bedload and suspension. We also considered the river characteristics, distinguishing between lowland rivers, gravel bed rivers and headwater streams. The results showed that a correlation exist between bedload and suspension for lowland and gravel bed rivers. This suggests that in gravel bed rivers a large part of the suspended load is fed by subsurface material, and depends on the remobilization of the surface material. No correlation was observed for head water streams where the sediment production is more likely related to hillslope processes. These results were used with a bedload transport equation for proposing a method for suspended load estimate. The method is rough, but especially for gravel bed rivers, it predicts suspended load reasonably well when compared to

  14. Comparison between experiment and theory in the temperature variation of film tension above the bulk isotropic transition in free-standing liquid-crystal films.

    Science.gov (United States)

    Veum, M; Duelge, L; Droske, J; Nguyen, H T; Huang, C C; Mirantsev, L V

    2009-09-01

    Using differential scanning calorimetry, the transition enthalpies and temperatures for the bulk smectic-isotropic phase transition have been measured for a series of liquid-crystal compounds. For five compounds, those values were used as parameters in a microscopic mean-field model to predict the temperature dependence of the difference in free-energy density between a sample of material in a free-standing smectic film and that in the bulk. The model predicts a weak temperature dependence below the bulk clearing point and a pronounced monotonic increase with temperature above the transition temperature. The compounds used in this study were chosen specifically because they were also the subject of a previous independent experimental study [M. Veum, Phys. Rev. E 74, 011703 (2006)] that demonstrated a sudden monotonic increase in the free-standing film tension with temperature, which is qualitatively consistent with the predictions of the above-mentioned mean-field model. This study presents a direct and quantitative comparison between the predictions of the mean-field model and the results from previous tension experiments.

  15. Influence of liquid crystalline phases on the tunability of a random laser

    Science.gov (United States)

    Trull, José; Salud, Josep; Diez-Berart, Sergio; López, David O.

    2017-05-01

    In this paper, we report the temperature behavior of an optimized disordered photonic system-based liquid crystal by means of heat capacity and refractive index measurements. The scattering system is formed by a porous borosilicate glass random matrix (about 60%) infiltrated with a smectogenic liquid crystal (about 16%) and a small amount of laser dye (0.1%). The rest of the scattering system is about 24% air, giving rise to a high refractive index contrast scattering system. Such a system has the functionality to change the refractive index contrast with temperature due to the liquid crystal temperature behavior. The system, optically pumped by the second harmonic of a Q -switched Nd:YAG pulsed laser working at 532 nm, exhibits random laser action, the threshold of which depends upon the liquid crystalline mesophase. Temperatures of existence of the smectic-B phase correspond to the most optimized random laser. In such a mesophase, the transport mean free path has been determined as about 16 μm in a coherent backscattering experiment.

  16. Liquid Ventilation

    Directory of Open Access Journals (Sweden)

    Qutaiba A. Tawfic

    2011-01-01

    Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.

  17. Subsidizing Liquidity

    DEFF Research Database (Denmark)

    Malinova, Katya; Park, Andreas

    2015-01-01

    Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...... the breakdown of trading fees between liquidity demanders and suppliers matters. Posted quotes adjust after the change in fee composition, but the transaction costs for liquidity demanders remain unaffected once fees are taken into account. However, as posted bid-ask spreads decline, traders (particularly...... retail) use aggressive orders more frequently, and adverse selection costs decrease....

  18. Ternary liquid-liquid equilibria for the phenolic compounds extraction from artificial textile industrial waste

    Science.gov (United States)

    Fardhyanti, Dewi Selvia; Prasetiawan, Haniif; Hermawan, Sari, Lelita Sakina

    2017-03-01

    Liquid waste in textile industry contains large amounts of dyes and chemicals which are capable of harming the environment and human health. It is due to liquid waste characteristics which have high BOD, COD, temperature, dissolved and suspended solid. One of chemical compound which might be harmful for environment when disposed in high concentration is phenol. Currently, Phenol compound in textile industrial waste has reached 10 ppm meanwhile maximum allowable phenol concentration is not more than 0.2 ppm. Otherwise, Phenol also has economic value as feedstock of plastic, pharmaceutical and cosmetic industry. Furthermore, suitable method to separate phenol from waste water is needed. In this research, liquid - liquid extraction method was used with extraction time for 70 minutes. Waste water sample was then separated into two layers which are extract and raffinate. Thereafter, extract and raffinate were then tested by using UV-Vis Spectrophotometer to obtained liquid - liquid equilibrium data. Aim of this research is to study the effect of temperature, stirring speed and type of solvent to obtain distribution coefficient (Kd), phenol yield and correlation of Three-Suffix Margules model for the liquid - liquid extraction data equilibrium. The highest extraction yield at 80.43 % was found by using 70% methanol as solvent at extraction temperature 50 °C with stirring speed 300 rpm, coefficient distribution was found 216.334. From this research it can be concluded that Three-Suffix Margules Model is suitable to predict liquid - liquid equilibrium data for phenol system.

  19. The Eighth Liquid Matter Conference.

    Science.gov (United States)

    Dellago, Christoph; Kahl, Gerhard; Likos, Christos N

    2012-07-18

    Daoulas, Victor Rühle and Kurt Kremer Smectic shellsTeresa Lopez-Leon, Alberto Fernandez-Nieves, Maurizio Nobili and Christophe Blanc Intrinsic profiles and the structure of liquid surfacesP Tarazona, E Chacón and F Bresme Competing ordered structures formed by particles with a regular tetrahedral patch decorationGünther Doppelbauer, Eva G Noya, Emanuela Bianchi and Gerhard Kahl Heterogeneous crystallization in colloids and complex plasmas: the role of binary mobilitiesH Löwen, E Allahyarov, A Ivlev and G E Morfill Isotope effects in water as investigated by neutron diffraction and path integral molecular dynamicsAnita Zeidler, Philip S Salmon, Henry E Fischer, Jörg C Neuefeind, J Mike Simonson and Thomas E Markland Confined cubic blue phases under shearO Henrich, K Stratford, D Marenduzzo, P V Coveney and M E Cates Depletion-induced biaxial nematic states of boardlike particlesS Belli, M Dijkstra and R van Roij Active Brownian motion tunable by lightIvo Buttinoni, Giovanni Volpe, Felix Kümmel, Giorgio Volpe and Clemens Bechinger Structure and stability of charged clustersMark A Miller, David A Bonhommeau, Christopher J Heard, Yuyoung Shin, Riccardo Spezia and Marie-Pierre Gaigeot Non-equilibrium relaxation and tumbling times of polymers in semidilute solutionChien-Cheng Huang, Gerhard Gompper and Roland G Winkler Thermophoresis of colloids by mesoscale simulationsDaniel Lüsebrink, Mingcheng Yang and Marisol Ripoll Computing the local pressure in molecular dynamics simulationsThomas W Lion and Rosalind J Allen Gradient-driven fluctuations in microgravityA Vailati, R Cerbino, S Mazzoni, M Giglio, C J Takacs and D S Cannell.

  20. Temperature signal in suspended sediment export from an Alpine catchment

    Directory of Open Access Journals (Sweden)

    A. Costa

    2018-01-01

    Full Text Available Suspended sediment export from large Alpine catchments ( >  1000 km2 over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc., transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation. Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity, and the activation of different potential sources of fine sediment (sediment supply in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment

  1. Self-assembly of gelator molecules in liquid crystals studied by ESR

    Science.gov (United States)

    Andreis, Mladen; Carić, Dejana; Vujičić, Nataša Šijaković; Jokić, Milan; Žinić, Mladen; Kveder, Marina

    2012-07-01

    Thermotropic liquid crystal trans-4-heptylcyclohexanecarboxylic acid (HCCA) doped with 4-oxo-2,2,6,6,-tetramethyl-1-piperidinyloxy spin probe (Tempone) is investigated by electron spin resonance (ESR) spectroscopy in the presence of chiral bisoxalamide gelator 1 during both cooling and heating cycles. In the temperature range 295-383 K, where HCCA displays isotropic, nematic, smectic B and crystalline phases, the impact of 1 self-organization was detected via (non) homogeneous partitioning of the spin probe in the environments varying in the polarity, an effect dependent on the gelator concentration. In particular, the evidence of the onset of the gelator network self-assembly in the nematic phase was detected by ESR at higher temperatures than the ones reported so far by other experimental techniques. Additionally, the spectral analysis points to the switching of the polarity in the vicinity of the spin probe when the transfer of chirality from 1 to HCCA upon cooling of the sample from isotropic to chiral nematic phase appears and when the event of LC gelation results in the achiral nematic phase during chiral gel fibers formation. When the gelation proceeds in the smectic phase, the melting of the gelator network is studied in the nematic phase during the heating cycle. Furthermore, the event of HCCA crystallization is shown to be strongly affected by the presence of 1 as well. The experimental evidence is provided that gelator network confines the HCCA into the domains within the bulk crystalline matrix where the local molecular dynamics are still not frozen. Therefore, we propose that non-homogeneous polarity profile of molecular organization/packing within LC gels could be determinable for the physical properties of various LC gel phases.

  2. Suspended sediment profiles derived from spectral attenuation coefficients measurements using neural network method

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, G.; Suresh, T.; Matondkar, S.G.P.; Desa, E.; Kamath, S.S.

    total suspended matter values from water samples obtained at discrete depths at the same location. An artificial neural network (ANN) model has been used to derive suspended matter from the spectral values of beam attenuation coefficients measured using...

  3. Impact of sound attenuation by suspended sediment on ADCP backscatter calibrations

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Vermeulen, B.

    2012-01-01

    Although designed for velocity measurements, acoustic Doppler current profilers (ADCPs) are widely being used to monitor suspended particulate matter in rivers and in marine environments. To quantify mass concentrations of suspended matter, ADCP backscatter is generally calibrated with in situ

  4. Effect of Martian Suspended Dust on Albedo Measurements from the MGS-TES Data

    OpenAIRE

    A. Zinzi; Palomba, E.; Rinaldi, G.; d'Amore, M.

    2010-01-01

    Suspended dust on Mars influences albedo measurements by orbiting instruments, but not necessary the real surface albedo. The aim of this study is to characterize the role of suspended aerosols on albedo measurement by remote sensing instruments.

  5. Design, analysis and control of cable-suspended parallel robots and its applications

    CERN Document Server

    Zi, Bin

    2017-01-01

    This book provides an essential overview of the authors’ work in the field of cable-suspended parallel robots, focusing on innovative design, mechanics, control, development and applications. It presents and analyzes several typical mechanical architectures of cable-suspended parallel robots in practical applications, including the feed cable-suspended structure for super antennae, hybrid-driven-based cable-suspended parallel robots, and cooperative cable parallel manipulators for multiple mobile cranes. It also addresses the fundamental mechanics of cable-suspended parallel robots on the basis of their typical applications, including the kinematics, dynamics and trajectory tracking control of the feed cable-suspended structure for super antennae. In addition it proposes a novel hybrid-driven-based cable-suspended parallel robot that uses integrated mechanism design methods to improve the performance of traditional cable-suspended parallel robots. A comparative study on error and performance indices of hybr...

  6. A gelatin liver phantom of suspended 90Y resin microspheres to simulate the physiologic microsphere biodistribution of a postradioembolization liver.

    Science.gov (United States)

    Kao, Yung Hsiang; Luddington, Oliver S; Culleton, Simone R; Francis, Roslyn J; Boucek, Jan A

    2014-12-01

    For phantom studies involving (90)Y PET/CT, homogeneous solutions of (90)Y, for example, (90)Y citrate, are commonly used. However, the microsphere biodistribution of a postradioembolization liver is never homogeneous; therefore, such phantoms are physiologically unrealistic for simulating clinical scenarios. The aim of this work was to develop a safe and practical phantom capable of simulating the heterogeneous microsphere biodistribution of a postradioembolization liver. Gelatin (5%) was used to suspend (90)Y resin microspheres, poured into plastic containers to simulate a liver with 2 tumors. Microspheres were added while the gelatin was maintained in a liquid state on a hot plate and continuously stirred with magnetic stir bars. The liquid microsphere mixture was then rapidly cooled in an ice bath while being stirred, resulting in a heterogeneous suspension of microspheres. The completed phantom was serially scanned by (90)Y PET/CT over 2 wk. All scans demonstrated a heterogeneous microsphere distribution throughout the liver and tumor inserts. Serendipitously, magnetic stir bars left inside the phantom produced CT artifacts similar to those caused by embolization coils, whereas pockets of air trapped within the gelatin during its preparation mimicked gas within hollow viscus. The microspheres and tumor inserts remained fixed and suspended within the gelatin, with no evidence of breakdown or leakage. A gelatin phantom realistically simulating the physiologic microsphere biodistribution of a postradioembolization liver is feasible to construct in a radiopharmacy. © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  7. 48 CFR 52.209-6 - Protecting the Government's Interest When Subcontracting With Contractors Debarred, Suspended, or...

    Science.gov (United States)

    2010-10-01

    ...'s Interest When Subcontracting With Contractors Debarred, Suspended, or Proposed for Debarment. 52....209-6 Protecting the Government's Interest When Subcontracting With Contractors Debarred, Suspended... Government's Interest When Subcontracting With Contractors Debarred, Suspended, or Proposed for Debarment...

  8. The effect of suspended particulate material on cyanobacteria--cyanophage interactions in liquid culture.

    Science.gov (United States)

    Barnet, Y M; Daft, M J; Stewart, W D

    1984-02-01

    The effect of the lytic phage LPP-DUN1 on the cyanobacterium Plectonema boryanum has been investigated in batch and in continuous cultures in the presence and absence of silt. In batch culture Plectonema without added phage grew normally; the presence of phage caused rapid lysis of the cyanobacterium and the addition of silt prevented lysis by the phage. In continuous culture the numbers of cyanobacterial cells and phage particles oscillated in a reciprocal manner, but the addition of silt damped down the oscillations in Plectonema biomass without decreasing the numbers of phage particles isolated from the cultures. The presence of silt thus appears to protect the cyanobacterium from lysis by phage, although the total numbers of phage particles are relatively unaffected by the silt, at least in the short-term.

  9. 78 FR 48145 - Lemon Juice From Argentina: Continuation of Suspended Antidumping Duty Investigation

    Science.gov (United States)

    2013-08-07

    ... Doc No: 2013-19067] DEPARTMENT OF COMMERCE International Trade Administration [A-357-818] Lemon Juice... of the suspended investigation on lemon juice from Argentina would likely lead to continuation or... of the suspended antidumping duty investigation on lemon juice from Argentina (``suspended...

  10. Suspended 3D pyrolytic carbon microelectrodes for electrochemistry

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Caviglia, Claudia; Keller, Stephan Sylvest

    2017-01-01

    Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes for electrochem...... resistance as compared to 2D carbon electrodes. The higher sensitivity of 3D carbon microelectrodes for electrochemical sensing was illustrated by dopamine detection.......Carbon microelectrodes have a wide range of applications because of their unique material properties and biocompatibility. This work presents the fabrication and characterization of suspended pyrolytic carbon microstructures serving as three-dimensional (3D) carbon microelectrodes...... for electrochemical applications. A 3D polymer template in epoxy based photoresist (SU-8) was fabricated with multiple steps of UV photolithography and pyrolysed at 900 °C to obtain 3D carbon microelectrodes. The pyrolytic carbon microstructures were characterized by SEM, Raman spectroscopy and XPS to determine...

  11. Approximate Series Solutions for Nonlinear Free Vibration of Suspended Cables

    Directory of Open Access Journals (Sweden)

    Yaobing Zhao

    2014-01-01

    Full Text Available This paper presents approximate series solutions for nonlinear free vibration of suspended cables via the Lindstedt-Poincare method and homotopy analysis method, respectively. Firstly, taking into account the geometric nonlinearity of the suspended cable as well as the quasi-static assumption, a mathematical model is presented. Secondly, two analytical methods are introduced to obtain the approximate series solutions in the case of nonlinear free vibration. Moreover, small and large sag-to-span ratios and initial conditions are chosen to study the nonlinear dynamic responses by these two analytical methods. The numerical results indicate that frequency amplitude relationships obtained with different analytical approaches exhibit some quantitative and qualitative differences in the cases of motions, mode shapes, and particular sag-to-span ratios. Finally, a detailed comparison of the differences in the displacement fields and cable axial total tensions is made.

  12. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    Science.gov (United States)

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  13. Remote Sensing of Suspended Sediment Dynamics in the Mississippi Sound

    Science.gov (United States)

    Merritt, D. N.; Skarke, A. D.; Silwal, S.; Dash, P.

    2016-02-01

    The Mississippi Sound is a semi-enclosed estuary between the coast of Mississippi and a chain of offshore barrier islands with relatively shallow water depths and high marine biodiversity that is wildly utilized for commercial fishing and public recreation. The discharge of sediment-laden rivers into the Mississippi Sound and the adjacent Northern Gulf of Mexico creates turbid plumes that can extend hundreds of square kilometers along the coast and persist for multiple days. The concentration of suspended sediment in these coastal waters is an important parameter in the calculation of regional sediment budgets as well as analysis of water-quality factors such as primary productivity, nutrient dynamics, and the transport of pollutants as well as pathogens. The spectral resolution, sampling frequency, and regional scale spatial domain associated with satellite based sensors makes remote sensing an ideal tool to monitor suspended sediment dynamics in the Northern Gulf of Mexico. Accordingly, the presented research evaluates the validity of published models that relate remote sensing reflectance with suspended sediment concentrations (SSC), for similar environmental settings, with 51 in situ observations of SSC from the Mississippi Sound. Additionally, regression analysis is used to correlate additional in situ observations of SSC in Mississippi Sound with coincident observations of visible and near-infrared band reflectance collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Aqua satellite, in order to develop a site-specific empirical predictive model for SSC. Finally, specific parameters of the sampled suspended sediment such as grain size and mineralogy are analyzed in order to quantify their respective contributions to total remotely sensed reflectance.

  14. On the Design of Suspended Roofs with Paraboloidal Surfaces

    Directory of Open Access Journals (Sweden)

    N. Ungureanu

    2006-01-01

    Full Text Available Some considerations concerning the design of the paraboloidal suspended roofs are made. The main geometric aspects are first time presented. For the roofs we propose, as pattern, the equivalent continuum membranes, and the efforts in the cable are determined by using the membrane efforts and their equations. Two examples are analyzed: elliptic paraboloide and hyperbolic paraboloide, with horizontal projection under the form of an ellipse.

  15. Technological advances in suspended-sediment surrogate monitoring

    Science.gov (United States)

    Gray, John R.; Gartner, Jeffrey W.

    2009-01-01

    Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous

  16. Segment Fixed Priority Scheduling for Self Suspending Real Time Tasks

    Science.gov (United States)

    2016-08-11

    for soft real- time systems [15]. Table 1 shows a brief... for execution are the times when a job of task arrives. For 2 ≤ ≤ , when , finishes its execution, it suspends itself for a time duration that lies...assume , and , can take non-negative values such that , ≤ , and let , = , . For each job, a segment , executes for a time duration that lies in

  17. Suspended biofilm carrier and activated sludge removal of acidic pharmaceuticals

    DEFF Research Database (Denmark)

    Falås, Per; Baillon-Dhumez, Aude; Andersen, Henrik Rasmus

    2012-01-01

    Removal of seven active pharmaceutical substances (ibuprofen, ketoprofen, naproxen, diclofenac, clofibric acid, mefenamic acid, and gemfibrozil) was assessed by batch experiments, with suspended biofilm carriers and activated sludge from several full-scale wastewater treatment plants. A distinct...... and attached solids for the carriers) of diclofenac, ketoprofen, gemfibrozil, clofibric acid and mefenamic acid compared to the sludges. Among the target pharmaceuticals, only ibuprofen and naproxen showed similar removal rates per unit biomass for the sludges and biofilm carriers. In contrast...

  18. Electro-optic bistability in organosiloxane bimesogenic liquid crystals

    Science.gov (United States)

    Gardiner, D. J.; Davenport, C. J.; Newton, J.; Coles, H. J.

    2006-06-01

    In this paper we report the electro-optic characterization of two homologous series of low molar mass bimesogenic siloxane-containing liquid crystals. The materials used have two alkoxycyanobiphenyl mesogenic units with variable alkyl chain joined by a two- or five-siloxane moiety and all exhibit stable smectic A mesophases over wide temperature ranges (up to 100 °C wide). Due to their inherent ruggedness these materials have potential for use in polarizer-free, bistable, scattering display and storage devices. The bistable modes are at low and high frequencies. The low frequency mode (write) is a highly scattering focal conic texture resulting from electrohydrodynamic instabilities while the high frequency mode (erase) is a clear state due to dielectric reorientation of the material. Both modes are preserved upon removal of the applied electric field. We present threshold voltages as a function of temperature, frequency, and cell thickness and response times as a function of voltage for each of the bistable modes. We find reduced threshold voltages (5<=Vth<=12 V/μm) and response times that are strongly dependent on applied voltage (50 ms<=τ<=10 s). These operating conditions would suggest that these materials are particularly suitable for slow update, large area, low power information panels and displays.

  19. Optimal control of suspended sediment distribution model of Talaga lake

    Science.gov (United States)

    Ratianingsih, R.; Resnawati, Azim, Mardlijah, Widodo, B.

    2017-08-01

    Talaga Lake is one of several lakes in Central Sulawesi that potentially to be managed in multi purposes scheme because of its characteristic. The scheme is addressed not only due to the lake maintenance because of its sediment but also due to the Algae farming for its biodiesel fuel. This paper governs a suspended sediment distribution model of Talaga lake. The model is derived from the two dimensional hydrodynamic shallow water equations of the mass and momentum conservation law of sediment transport. An order reduction of the model gives six equations of hyperbolic systems of the depth, two dimension directional velocities and sediment concentration while the bed elevation as the second order of turbulent diffusion and dispersion are neglected. The system is discreted and linearized such that could be solved numerically by box-Keller method for some initial and boundary condition. The solutions shows that the downstream velocity is play a role in transversal direction of stream function flow. The downstream accumulated sediment indicate that the suspended sediment and its changing should be controlled by optimizing the downstream velocity and transversal suspended sediment changing due to the ideal algae growth need.

  20. Intergrating cavity absorption meter measurements of dissolved substances and suspended particles in ocean water

    Science.gov (United States)

    Pope, Robin M.; Weidemann, Alan D.; Fry, Edward S.

    2000-01-01

    We have developed a new device to measure the separate contributions to the spectral absorption coefficient due to a pure liquid, due to the particles suspended in it, and due to the substances dissolved in it. This device, the Integrating Cavity Absorption Meter (ICAM), is essentially independent of scattering effects in the sample. In April 1993, a prototype of the ICAM was field tested on board the research vessel USNS Bartlett. A major part of the cruise track included criss-crossing the area where the Mississippi flows into the Gulf of Mexico at various ranges from the mouth of the river; thus samples were collected from areas of blue, green, and brown/black water. We evaluated 35 seawater samples collected with 5-l Niskin bottles from 22 locations to determine absorption spectra (380-700 nm) of suspended particles and dissolved substances (gelbstoff). Results validate the ICAM as a viable tool for marine optical absorption research. Gelbstoff absorption at 432.5 nm ranged from 0.024 to 0.603 m -1. Over the spectral region 380→560 nm, gelbstoff absorption by each of the samples could be accurately fit to a decaying exponential. The particle absorption spectra are generally characteristic of those of phytoplankton and exhibit a local maximum at 430-440 nm. Absorption values at 432.5 nm ranged from ˜zero to ˜1.0 m -1. Some samples with moderate particulate absorption, however, did not show the characteristic local maximum of phytoplankton in the blue and instead resembled the characteristic decaying exponential of detritus with a shape similar to that observed in the gelbstoff. The ratio of gelbstoff to particulate absorption at 432.5 nm ranged from 0.46 to 152.

  1. Managing liquidity

    DEFF Research Database (Denmark)

    Pokutta, Sebastian; Schmaltz, Christian

    2011-01-01

    Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de-)centraliza......Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de......-)centralization. We provide an analytical solution for the 2-branch model and show that a liquidity center can be interpreted as an option on immediate liquidity. Therefore, its value can be interpreted as the price of information, i.e., the price of knowing the exact demand. Furthermore, we derive the threshold...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...

  2. Shapes and singularities in triatic liquid-crystal vesicles

    Science.gov (United States)

    Bowick, Mark J.; Manyuhina, O. V.; Serafin, F.

    2017-01-01

    Determining the equilibrium configuration and shape of curved two-dimensional films with (generalized) liquid-crystalline order is a difficult infinite-dimensional problem of direct relevance to the study of generalized polymersomes, soft matter and the fascinating problem of understanding the origin and formation of shape (morphogenesis). The symmetry of the free energy of the LC film being considered and the topology of the surface to be determined often requires that the equilibrium configuration possesses singular structures in the form of topological defects such as disclinations for nematic films. The precise number and type of defect plays a fundamental role in restricting the space of possible equilibrium shapes. Flexible closed vesicles with spherical topology and nematic or smectic order, for example, inevitably possess four elementary strength +1/2 disclination defects positioned at the four vertices of a tetrahedral shell. Here we address the problem of determining the equilibrium shape of flexible vesicles with generalized liquid-crystalline order. The order parameter in these cases is an element of S^1/Zp , for any positive integer p. We will focus on the case p =3 , known as triatic liquid crystals (LCs). We construct the appropriate order parameter for triatics and find the associated free energy. We then describe the structure of the elementary defects of strength +1/3 in flat space. Finally, we prove that sufficiently floppy triatic vesicles with the topology of the 2-sphere equilibrate to octahedral shells with strength +1/3 defects at each of the six vertices, independently of the scale.

  3. Highly tilted liquid crystalline materials possessing a direct phase transition from antiferroelectric to isotropic phase

    Energy Technology Data Exchange (ETDEWEB)

    Milewska, K.; Drzewiński, W. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Czerwiński, M., E-mail: mczerwinski@wat.edu.pl [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Dąbrowski, R. [Institute of Chemistry, Military University of Technology, 00-908 Warsaw (Poland); Piecek, W. [Institute of Applied Physics, Military University of Technology, 00-908 Warsaw (Poland)

    2016-03-01

    Pure compounds and multicomponent mixtures with a broad temperature range of high tilted liquid crystalline antiferroelectric phase and a direct phase transition from antiferroelectric to isotropic phase, were obtained. X-ray diffraction analysis confirms these kinds of materials form a high tilted anticlinic phase, with a fixed layer spacing and very weak dependency upon temperature, after the transition from the isotropic phase. Due to this, not only pure orthoconic antiferroelectric liquid crystals but also those with a moderate tilt should generate a good dark state. Furthermore, due to the increased potential for forming anticlinic forces, such materials could minimize a commonly observed asymmetry of a rise and fall switching times at a surface stabilized geometry. - Highlights: • The new class of liquid crystalline materials with the direct SmC{sub A}*. • Iso phase transition were obtained. • Materials possess the layer spacing fixed and very weak dependent upon temperature. • Smectic layers without shrinkage are observed. • A good dark state can be generate in SSAFLC.

  4. Coalescence Processes of Droplets and Liquid Marbles

    Directory of Open Access Journals (Sweden)

    Jing Jin

    2017-11-01

    Full Text Available The coalescence process of droplets and, more recently, of liquid marbles, has become one of the most essential manipulation schemes in digital microfluidics. This process is indispensable for realising microfluidic functions such as mixing and reactions at microscale. This paper reviews previous studies on droplet coalescence, paying particular attention to the coalescence of liquid marbles. Four coalescence systems have been reviewed, namely, the coalescence of two droplets freely suspended in a fluid; the coalescence of two sessile droplets on a solid substrate; the coalescence of a falling droplet and a sessile droplet on a solid substrate; and liquid marble coalescence. The review is presented according to the dynamic behaviors, physical mechanisms and experimental parameters of the coalescence process. It also provides a systematic overview of how the coalescence process of droplets and liquid marbles could be induced and manipulated using external energy. In addition, the practical applications of liquid marble coalescence as a novel microreactor are highlighted. Finally, future perspectives on the investigation of the coalescence process of liquid marbles are proposed. This review aims to facilitate better understanding of the coalescence of droplets and of liquid marbles as well as to shed new insight on future studies.

  5. Liquid explosives

    CERN Document Server

    Liu, Jiping

    2015-01-01

    The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.

  6. System and method for liquid extraction electrospray-assisted sample transfer to solution for chemical analysis

    Science.gov (United States)

    Kertesz, Vilmos; Van Berkel, Gary J.

    2016-07-12

    A system for sampling a surface includes a surface sampling probe comprising a solvent liquid supply conduit and a distal end, and a sample collector for suspending a sample collection liquid adjacent to the distal end of the probe. A first electrode provides a first voltage to solvent liquid at the distal end of the probe. The first voltage produces a field sufficient to generate electrospray plume at the distal end of the probe. A second electrode provides a second voltage and is positioned to produce a plume-directing field sufficient to direct the electrospray droplets and ions to the suspended sample collection liquid. The second voltage is less than the first voltage in absolute value. A voltage supply system supplies the voltages to the first electrode and the second electrode. The first electrode can apply the first voltage directly to the solvent liquid. A method for sampling for a surface is also disclosed.

  7. Understanding the ice nucleation characteristics of feldspars suspended in solution

    Science.gov (United States)

    Kumar, Anand; Marcolli, Claudia; Kaufmann, Lukas; Krieger, Ulrich; Peter, Thomas

    2017-04-01

    Freezing of liquid droplets and subsequent ice crystal growth affects optical properties of clouds and precipitation. Field measurements show that ice formation in cumulus and stratiform clouds begins at temperatures much warmer than those associated with homogeneous ice nucleation in pure water, which is ascribed to heterogeneous ice nucleation occurring on the foreign surfaces of ice nuclei (IN). Various insoluble particles such as mineral dust, soot, metallic particles, volcanic ash, or primary biological particles have been suggested as IN. Among these the suitability of mineral dusts is best established. The ice nucleation ability of mineral dust particles may be modified when secondary organic or inorganic substances are accumulating on the dust during atmospheric transport. If the coating is completely wetting the mineral dust particles, heterogeneous ice nucleation occurs in immersion mode also below 100 % RH. A previous study by Zobrist et al. (2008) Arizona test dust, silver iodide, nonadecanol and silicon dioxide suspensions in various solutes showed reduced ice nucleation efficiency (in immersion mode) of the particles. Though it is still quite unclear how surface modifications and coatings influence the ice nucleation activity of the components present in natural dust particles at a microphysical scale. To improve our understanding how solute and mineral dust particle surface interaction, we run freezing experiments using a differential scanning calorimeter (DSC) with microcline, sanidine, plagioclase, kaolinite and quartz particles suspended in pure water and solutions containing ammonia, ammonium bisulfate, ammonium sulfate, ammonium chloride, ammonium nitrate, potassium chloride, potassium sulfate, sodium sulfate and sulfuric acid. Methodology Suspensions of mineral dust samples (2 - 5 wt%) are prepared in water with varying solute concentrations (0 - 15 wt%). 20 vol% of this suspension plus 80 vol% of a mixture of 95 wt% mineral oil (Aldrich

  8. Progress towards Acoustic Suspended Sediment Transport Monitoring: Fraser River, BC

    Science.gov (United States)

    Attard, M. E.; Venditti, J. G.; Church, M. A.; Kostaschuk, R. A.

    2011-12-01

    Our ability to predict the timing and quantity of suspended sediment transport is limited because fine sand, silt and clay delivery are supply limited, requiring empirical modeling approaches of limited temporal stability. A solution is the development of continuous monitoring techniques capable of tracking sediment concentrations and grain-size. Here we examine sediment delivery from upstream sources to the lower Fraser River. The sediment budget of the lower Fraser River provides a long-term perspective of the net changes in the channels and in sediment delivery to Fraser Delta. The budget is based on historical sediment rating curves developed from data collected from 1965-1986 by the Water Survey of Canada. We explore the possibility of re-establishing the sediment-monitoring program using hydro-acoustics by evaluating the use of a 300 kHz side-looking acoustic Doppler current profiler (aDcp), mounted just downstream of the sand-gravel transition at Mission, for continuous measurement of suspended sediment transport. Complementary field observations include conventional bottle sampling with a P-63 sampler, vertical profiles with a downward-looking 600 kHz aDcp, and 1200 kHz aDcp discharge measurements. We have successfully completed calibration of the downward-looking aDcp with the P-63 samples; the side-looking aDcp signals remain under investigation. A comparison of several methods for obtaining total sediment flux indicates that suspended sediment concentration (SSC) closely follows discharge through the freshet and peaks in total SSC and sand SSC coincide with peak measurements of discharge. Low flows are dominated by fine sediment and grain size increases with higher flows. This research assesses several techniques for obtaining sediment flux and contributes to the understanding of sediment delivery to sand-bedded portions of the river.

  9. Surface-enhanced Raman scattering of suspended monolayer graphene

    Science.gov (United States)

    Huang, Cheng-Wen; Lin, Bing-Jie; Lin, Hsing-Ying; Huang, Chen-Han; Shih, Fu-Yu; Wang, Wei-Hua; Liu, Chih-Yi; Chui, Hsiang-Chen

    2013-11-01

    The interactions between phonons and electrons induced by the dopants or the substrate of graphene in spectroscopic investigation reveal a rich source of interesting physics. Raman spectra and surface-enhanced Raman spectra of supported and suspended monolayer graphenes were measured and analyzed systemically with different approaches. The weak Raman signals are greatly enhanced by the ability of surface-enhanced Raman spectroscopy which has attracted considerable interests. The technique is regarded as wonderful and useful tool, but the dopants that are produced by depositing metallic nanoparticles may affect the electron scattering processes of graphene. Therefore, the doping and substrate influences on graphene are also important issues to be investigated. In this work, the peak positions of G peak and 2D peak, the I 2D/ I G ratios, and enhancements of G and 2D bands with suspended and supported graphene flakes were measured and analyzed. The peak shifts of G and 2D bands between the Raman and SERS signals demonstrate the doping effect induced by silver nanoparticles by n-doping. The I 2D/ I G ratio can provide a more sensitive method to carry out the doping effect on the graphene surface than the peak shifts of G and 2D bands. The enhancements of 2D band of suspended and supported graphenes reached 138, and those of G band reached at least 169. Their good enhancements are helpful to measure the optical properties of graphene. The different substrates that covered the graphene surface with doping effect are more sensitive to the enhancements of G band with respect to 2D band. It provides us a new method to distinguish the substrate and doping effect on graphene.

  10. Coupling between electronic transport and longitudinal phonons in suspended nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sapmaz, S; Jarillo-Herrero, P; Blanter, Ya M; Zant, H S J van der [Kavli Institute of Nanoscience, Delft University of Technology, PO Box 5046, 2600 GA Delft (Netherlands)

    2005-11-15

    Current-voltage characteristics of suspended single-wall carbon nanotube (NT) quantum dots show a series of steps equally spaced in voltage. The energy scale of this harmonic, low-energy excitation spectrum is consistent with that of the longitudinal low-k phonon mode in the NT. Agreement is found with a Franck-Condon-based model in which the phonon-assisted tunnelling process is modelled as a coupling of electronic levels to underdamped quantum harmonic oscillators. Comparison with this model indicates a rather strong electron-phonon coupling factor of order unity. We investigate different electron-phonon coupling mechanisms and give estimates of the coupling factor.

  11. Regional volume changes in canine lungs suspended in air

    Science.gov (United States)

    Abbrecht, Peter H.; Kyle, Richard R.; Bryant, Howard J.; Feuerstein, Irwin

    1995-01-01

    The purpose of this study was to determine the effect of the absence of a pleural pressure gradient (simulating the presumed condition found in microgravity) upon regional expansion of the lung. We attempted to produce a uniform pressure over the surface of the lung by suspending excised lungs in air. Such studies should help determine whether or not the absence of a pleural pressure gradient leads to uniform ventilation. A preparation in which there is no pleural pressure gradient should also be useful in studying non-gravitational effects on ventilation distribution.

  12. Suspended liminality: Vacillating affects in cyberbullying/research

    OpenAIRE

    Kofoed, J.; Stenner, Paul

    2017-01-01

    This paper develops a concept of liminal hotspots in the context of i) a secondary analysis of a cyberbullying case involving a group of school children from a Danish school, and ii) an altered auto-ethnography in which the authors ‘entangle’ their own experiences with the case analysis. These two sources are used to build an account of a liminal hotspot conceived as an occasion of troubled and suspended transformative transition in which a liminal phase is extended and remains unresolved. Th...

  13. Liquid Crystals

    Science.gov (United States)

    1990-01-01

    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  14. Remote Sensing Studies of Suspended Sediment Concentration Variation in Barito Delta

    Science.gov (United States)

    Arisanty, Deasy; Nur Saputra, Aswin

    2017-12-01

    The dynamic of suspended sediment concentration in Barito Delta depend on the process in upstream. Agriculture, mining, and illegal logging in Barito River upstream has an effect for suspended sediment concentration in Barito Delta. The objective of research is to estimate the variation of suspended sediment concentration in Barito Delta. The data of research consist of Landsat 7 in year 2011 and measurement result data of suspended sediment concentration both in wet season and dry season in year 2011. Data analysis is regression analysis to estimates the variation of suspended sediment concentration in Barito Delta. The method of research compares three types of spectral transformation for suspended sediment that is Normalized Suspended Material Index (NSMI), Normalized Differences Suspended Sediment Index (NDSSI), and band ratio (green/blue). The result of the transformation is compared with the value of the field measurement. Based on the result of the comparison can be known the suitable type of transformation for the suspended sediment estimation in Barito Delta. The result of research explains that NSMI has the highest value to estimate the variation of suspended sediment concentration in Barito Delta.

  15. Influence of ZnO nanostructures in liquid crystal interfaces for bistable switching applications

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kaushik, E-mail: kaushikpal@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China); Zhan, Bihong, E-mail: bihong_zhan@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China); Madhu Mohan, M.L.N. [Liquid Crystal Research Laboratory (LCRL), Bannari Amman Institute of Technology, Sathyamangalam 638 401 (India); Schirhagl, Romana [University Medical Center Groningen, Department of BioMedical Engineering, Ant. Deusinglaan 1, 9713 AV Groningen (Netherlands); Wang, Guoping, E-mail: guopingwang@whu.edu.cn [School of Power and Mechanical Engineering, Wuhan University, 8 East Lake South Road, Wuhan 430072 (China)

    2015-12-01

    Graphical abstract: - Highlights: • One step bench top novel synthesis and growth dynamics of ZnO structures are successfully performed. • Nanostructures dispersing liquid crystals (NDLC) is recently found to have significant influence on the nucleation and growth of many functional nanocrystals (NCs), and provide a fundamental approach to modify the crystallographic phase, size, morphology, and electronic configuration of nanomaterials. • Electro-optical switching application ensures the bright field droplet design marble pattern of smectic G phase, nematic and most significant twist nematic phase pattern are obtained. • Spontaneous polarization, rotational viscosity and response time study, exploring smart applications in LCD technology. - Abstract: The controlled fabrication of nanometer-scale objects is without doubt one of the central issues in current science and technology. In this article, we exhibit a simple, one-step bench top synthesis of zinc oxide nano-tetrapods and nano-spheres which were tailored by the facial growth of nano-wires (diameter ≈ 24 nm; length ≈ 118 nm) and nano-cubes (≈395 nm edge) to nano-sphere (diameter ≈ 585 nm) appeaded. The possibilities of inexpensive, simple solvo-chemical synthesis of nanostructures were considered. In this article, a successful attempt has been made that ZnO nano-structures dispersed on well aligned hydrogen bonded liquid crystals (HBLC) comprising azelaic acid (AC) with p-n-alkyloxy benzoic acid (nBAO) by varying the respective alkyloxy carbon number (n = 5). The dispersion of nanomaterials with HBLC is an effective route to enhance the existing functionalities. A series of these composite materials were analyzed by polarizing optical microscope's electro-optical switching. An interesting feature of AC + nBAO is the inducement of tilted smectic G phase with increasing carbon chain length. Phase diagrams of the above hybrid ZnO nanomaterial influenced LC complex and pure LC were

  16. Transformations of Liquid Metals in Ionic Liquid

    OpenAIRE

    Liu, Fujun; Yu, Yongze; Liu, Jing

    2017-01-01

    Experimental studies were carried out on the motions and transformations of liquid metal in ionic liquid under applied electric field. The induced vortex rings and flows of ionic liquid were determined via the photographs taken sequentially over the experiments. The polarization of electric double layer of liquid metals was employed to explain the flow of ionic liquid with the presence of liquid metal. Unlike former observation of liquid metal machine in conventional solution, no gas bubble w...

  17. Spin-crossover and liquid crystal properties in 2D cyanide-bridged Fe(II)-M(I/II) metalorganic frameworks.

    Science.gov (United States)

    Seredyuk, M; Gaspar, A B; Ksenofontov, V; Galyametdinov, Y; Verdaguer, M; Villain, F; Gütlich, P

    2010-11-01

    Novel two-dimensional heterometallic Fe(II)-M(Ni(II), Pd(II), Pt(II), Ag(I), and Au(I)) cyanide-bridged metalorganic frameworks exhibiting spin-crossover and liquid crystal properties, formulated as {FeL(2)[M(I/II)(CN)(x)](y)}·sH(2)O, where L are the ligands 4-(4-alkoxyphenyl)pyridine, 4-(3,4-dialkoxyphenyl)pyridine, and 4-(3,4,5-trisalkoxyphenyl)pyridine, have been synthesized and characterized. The physical characterization has been carried out by means of EXAFS, X-ray powder diffraction, magnetic susceptibility, differential scanning measurements, and Mössbauer spectroscopy. The 2D Fe(II) metallomesogens undergo incomplete and continuous thermally induced spin transition at T(1/2) ≈ 170 K and crystal-to-smectic transition above 370 K.

  18. Thermoelectric unipolar spin battery in a suspended carbon nanotube

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-01

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when {{k}\\text{B}}T is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  19. Thermoelectric unipolar spin battery in a suspended carbon nanotube.

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-26

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when [Formula: see text] is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  20. IUTAM symposium on hydrodynamic diffusion of suspended particles

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.H. [ed.

    1995-12-31

    Hydrodynamic diffusion refers to the fluctuating motion of nonBrownian particles (or droplets or bubbles) which occurs in a dispersion due to multiparticle interactions. For example, in a concentrated sheared suspension, particles do not move along streamlines but instead exhibit fluctuating motions as they tumble around each other. This leads to a net migration of particles down gradients in particle concentration and in shear rate, due to the higher frequency of encounters of a test particle with other particles on the side of the test particle which has higher concentration or shear rate. As another example, suspended particles subject to sedimentation, centrifugation, or fluidization, do not generally move relative to the fluid with a constant velocity, but instead experience diffusion-like fluctuations in velocity due to interactions with neighboring particles and the resulting variation in the microstructure or configuration of the suspended particles. In flowing granular materials, the particles interact through direct collisions or contacts (rather than through the surrounding fluid); these collisions also cause the particles to undergo fluctuating motions characteristic of diffusion processes. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  1. Suspended animation-like state protects mice from lethal hypoxia.

    Science.gov (United States)

    Blackstone, Eric; Roth, Mark B

    2007-04-01

    Joseph Priestley observed the high burn rate of candles in pure oxygen and wondered if people would "live out too fast" if we were in the same environment. We hypothesize that sulfide, a natural reducer of oxygen that is made in many cell types, acts as a buffer to prevent unrestricted oxygen consumption. To test this, we administered sulfide in the form of hydrogen sulfide (H2S) to mice (Mus musculus). As we have previously shown, H2S decreases the metabolic rate of mice by approximately 90% and induces a suspended animation-like state. Mice cannot survive for longer than 20 min when exposed to 5% oxygen. However, if mice are first put into a suspended animation-like state by a 20-min pretreatment with H2S and then are exposed to low oxygen, they can survive for more than 6.5 h in 5% oxygen with no apparent detrimental effects. In addition, if mice are exposed to a 20-min pretreatment with H2S followed by 1 h at 5% oxygen, they can then survive for several hours at oxygen tensions as low as 3%. We hypothesize that prior exposure to H2S reduces oxygen demand, therefore making it possible for the mice to survive with low oxygen supply. These results suggest that H2S may be useful to prevent damage associated with hypoxia.

  2. A Passively-Suspended Tesla Pump Left Ventricular Assist Device

    Science.gov (United States)

    Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

  3. Assessment of CO, CO2 and Suspended Particulate Matter Emissions

    Directory of Open Access Journals (Sweden)

    Bala Isah ABDULKARIM

    2007-09-01

    Full Text Available The concentrations of carbon oxides (CO and CO2 and suspended particulate matter at Benue Cement Company (BCC and Tse-Kucha community was investigated. Results obtained, shows that concentrations of carbon dioxide of 34.40ppm, 39.50 ppm, 48.50 ppm, 78.55 ppm, 65.25 ppm, 26.80 ppm and 29.5 ppm for quarry, raw mill, cement mill, Kiln, packing house, limestone stockpile and Tse-Kucha community respectively were below the maximum standard natural concentration of CO2 in atmosphere of 600ppm while concentrations of CO (1.25ppm - 4.00ppm measured in all the sample stations were below the Nigerian Ambient Air Quality Standards (NAAQS and WHO max limit of 10 ppm - 20 ppm for an 8-hourly average time. Lastly, the concentrations of suspended particulate matter of 375 μg/m3, 338 μg/m3 and 290 μg/m3 at the cement mill, packing house and raw mill respectively were also above the World Health Organization’s (WHO’s Guidelines and Standards for Ambient Air Quality which stipulates a range of 150 μg/m3 to 230 μg/m3 for a 24- hourly average.

  4. Coagulation-Sedimentation-Extraction Pretreatment Methods for The Removal of Suspended Solids and Residual Oil From Palm Oil Mill Effluent (Pome

    Directory of Open Access Journals (Sweden)

    Abdul Latif Ahmad, Norliza Ibrahim , Suzylawati Ismail and Subhash Bhatia

    2012-08-01

    Full Text Available Suspended solids and residual oil removal in a liquid are relevant to numerous research areas and industry. The suspended solid cannot be removed completely by plain settling. Large and heavy particles can settle out readily, but smaller and lighter particles settle very slowly or in some cases do not settle at all. Because of this, it requires efficient physical-chemical pretreatment methods.   Our current research is to study the pretreatment methods in the removal of suspended solids and residual oil content in POME. Preliminary analysis shows that POME contains 40,000 mg/L suspended solid and 4,000 mg/L oil and grease content that relatively very high compared to the maximum allowable limit by the Malaysian Department of Environment which are only 400 mg/L and 50 mg/L respectively. The methods chosen were coagulation-sedimentation method for suspended solids removal and solvent extraction for residual oil removal.  Jar test apparatus was used as the standard procedure for bench-scale testing and alum was used as the coagulant. Parameters studied were alum dosage, mixing time, mixing speed, sedimentation time and pH. For removal of residual oil, six different organic solvents; n-hexane, n-heptane, benzene, petroleum ether, pentane and petroleum benzene were used. For every solvent the effect of solvent ratio, mixing time, mixing speed and pH were analyzed. The results show that the optimum conditions in removal of suspended solid from POME were at pH 4.11, sedimentation time of 100 minutes and 150 rpm mixing speed with 1.5 hr mixing time. N-hexane give the best performance in extracting residual oil from POME with solvent to POME ratio of 6:10. It was estimated about 0.54 grams of oil and grease can be extracted with optimum variables at pH 4, mixing speed of 200 rpm, and 20 minutes mixing time.  Key Words: palm oil mill effluent, coagulation, suspended solid, residual oil, solvent extraction.

  5. Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

    Directory of Open Access Journals (Sweden)

    J.M. Ilnytskyi

    2010-01-01

    Full Text Available A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008]. Coarse-grained (CG molecular dynamics (MD simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like, leading to formation of a monodomain smectic A (SmA or a columnar (Col phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

  6. Colloidal membranes: The rich confluence of geometry and liquid crystals

    Science.gov (United States)

    Kaplan, Cihan Nadir

    A simple and experimentally realizable model system of chiral symmetry breaking is liquid-crystalline monolayers of aligned, identical hard rods. In these materials, tuning the chirality at the molecular level affects the geometry at systems level, thereby inducing a myriad of morphological transitions. This thesis presents theoretical studies motivated by the rich phenomenology of these colloidal monolayers. High molecular chirality leads to assemblages of rods exhibiting macroscopic handedness. In the first part we consider one such geometry, twisted ribbons, which are minimal surfaces to a double helix. By employing a theoretical approach that combines liquid-crystalline order with the preferred shape, we focus on the phase transition from simple flat monolayers to these twisted structures. In these monolayers, regions of broken chiral symmetry nucleate at the interfaces, as in a chiral smectic A sample. The second part particularly focuses on the detailed structure and thermodynamic stability of two types of observed interfaces, the monolayer edge and domain walls in simple flat monolayers. Both the edge and "twist-walls" are quasi-one-dimensional bands of molecular twist deformations dictated by local chiral interactions and surface energy considerations. We develop a unified theory of these interfaces by utilizing the de Gennes framework accompanied by appropriate surface energy terms. The last part turns to colloidal "cookies", which form in mixtures of rods with opposite handedness. These elegant structures are essentially flat monolayers surrounded by an array of local, three dimensional cusp defects. We reveal the thermodynamic and structural characteristics of cookies. Furthermore, cookies provide us with a simple relation to determine the intrinsic curvature modulus of our model system, an important constant associated with topological properties of membranes. Our results may have impacts on a broader class of soft thin films.

  7. Development of an Integrated Suspended Sediment Sampling System - Prototype Results

    Science.gov (United States)

    Nerantzaki, Sofia; Moirogiorgou, Konstantia; Efstathiou, Dionissis; Giannakis, George; Voutsadaki, Stella; Zervakis, Michalis; Sibetheros, Ioannis A.; Zacharias, Ierotheos; Karatzas, George P.; Nikolaidis, Nikolaos P.

    2015-04-01

    The Mediterranean region is characterized by a unique micro-climate and a complex geologic and geomorphologic environment caused by its position in the Alpine orogenesis belt. Unique features of the region are the temporary rivers that are dry streams or streams with very low flow for most of the time over decadal time scales. One of their key characteristics is that they present flashy hydrographs with response times ranging from minutes to hours. It is crucial to monitor flash-flood events and observe their behavior since they can cause environmental degradation of the river's wider location area. The majority of sediment load is transferred during these flash events. Quantification of these fluxes through the development of new measuring devices is of outmost importance as it is the first step for a comprehensive understanding of the water quality, the soil erosion and erosion sources, and the sediment and nutrient transport routes. This work proposes an integrated suspended sediment sampling system which is implemented in a complex semi-arid Mediterranean watershed (i.e. the Koiliaris River Basin of Crete) with temporary flow tributaries and karstic springs. The system consists of sensors monitoring water stage and turbidity, an automated suspended sediment sampler, and an online camera recording video sequence of the river flow. Water stage and turbidity are continuously monitored and stage is converted to flow with the use of a rating curve; when either of these variables exceeds certain thresholds, the pump of the sediment sampler initiates sampling with a rotation proportional to the stage (flow weighted sampling). The water passes through a filter that captures the sediment, the solids are weighted after each storm and the data are converted to a total sediment flux. At the same time, the online camera derives optical measurements for the determination of the two-dimensional river flow velocity and the spatial sediment distribution by analyzing the Hue

  8. Electrodialytic remediation of suspended soil – Comparison of two different soil fractions

    DEFF Research Database (Denmark)

    Sun, Tian Ran; Ottosen, Lisbeth M.; Jensen, Pernille Erland

    2012-01-01

    from the original soil and the soil fines in experiments with identical charge transportation, higher removal efficiency was observed from the soil fines. Constant current with 5mA could be maintained at L/S 3.5 for the soil fines while not for the original soil. Doubling current to 10mA could......Electrodialytic remediation (EDR) can be used for removal of heavy metals from suspended soil, which allows for the soil remediation to be a continuous process. The present paper focused on the processing parameters for remediation of a soil polluted with Cu and As from wood preservation. Six...... electrodialytic treatments lasting from 5 to 22 days with different liquid to solid ratio (L/S) and current intensity were conducted. Among treatments, the highest removal was obtained from the soil fines with 5mA current at L/S 3.5 after 22 days where 96% of Cu and 64% of As were removed. Comparing the removal...

  9. THE HYDROLOGIC CYCLE, UNIDIRECTIONAL CHARTER OF THE DISSOLVED SALTS AND SUSPENDED LOAD

    Directory of Open Access Journals (Sweden)

    Nicolae Florea

    2012-12-01

    Full Text Available In this paper it is underlined that the hydrologic cycle in nature, reversible and regenerating of fresh water, carries out also an unidirectional and irreversible circulation – by means of a fragment of the hydrologic cycle – of the dissolved salts and stream’s suspended load, entailed by the water drained from continents to ocean. The trend is to transfer soluble salts from land to ocean in the same time with the running water on land in the portion of the hydrologic cycle which refers to the water transfer from continents to ocean in order to equilibrate the annual water balance of the hydrologic cycle. But, one can realize here and there some local salt accumulations in salt soils or in salt lakes within areas without drainage in arid climate; these salts accumulations are cases of local hydrologic cycles „grafted” along the way of water on land (to ocean. The energy necessary to the hydrologic cycle in nature is delivered by the Sun, and the entropy remains at a low level as a consequence of the elimination in this cycle of water vapors with high entropy, and of the receiving of liquid or solid water with low entropy, so that the annual level of entropy is maintained at a low level.

  10. Liquid Marbles

    KAUST Repository

    Khalil, Kareem

    2012-12-01

    Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some

  11. Suspended Integrated Strip-line Transition Design for Highly Integrated Radar Systems

    Science.gov (United States)

    2017-03-01

    Frequency Structural Figure 3. Internal-view of SISL thru structure. Figure 2. Suspended substrate strip- line side -view. Figure 4. Top-view of trace and...response, you can see that the measured response is shifted to Figure 2. Suspended Substrate Strip- line Side -View Figure 5. Fabricated thru line ...Suspended Integrated Strip- line Transition Design for Highly Integrated Radar Systems Jay W. McDaniel, Shahrokh Saeedi, Mark B. Yeary, and

  12. Drying of liquid food droplets : enzyme inactivation and multicomponent diffusion

    OpenAIRE

    Meerdink, G.

    1993-01-01

    In this thesis the drying of liquid food droplets is studied from three different points of view: drying kinetics, enzyme inactivation and multicomponent diffusion. Mathematical models are developed and validated experimentally.

    Drying experiments are performed with suspended droplets and with free falling droplets under spray-drying conditions. The experiments with the free falling droplets are performed in a specially designed drying tower using a resonance nozzle. The reso...

  13. Electrically Addressable Optical Devices Using A System Of Composite Layered Flakes Suspended In A Fluid Host To Obtain Angularly Depende

    Science.gov (United States)

    Kosc, Tanya Z.; Marshall, Kenneth L.; Jacobs, Stephen D.

    2004-12-07

    Composite or layered flakes having a plurality of layers of different materials, which may be dielectric materials, conductive materials, or liquid crystalline materials suspended in a fluid host and subjected to an electric field, provide optical effects dependent upon the angle or orientation of the flakes in the applied electric field. The optical effects depend upon the composition and thickness of the layers, producing reflectance, interference, additive and/or subtractive color effects. The composition of layered flakes may also be selected to enhance and/or alter the dielectric properties of flakes, whereby flake motion in an electric field is also enhanced and/or altered. The devices are useful as active electro-optical displays, polarizers, filters, light modulators, and wherever controllable polarizing, reflecting and transmissive optical properties are desired.

  14. Fluorescence decay of CdSe nanoparticles in Liquid Crystals near Phase Transitions

    Science.gov (United States)

    North, Darren; Beck, Samuel; Gray, Jodie; Drye, Shane; Prayaga, Chandra; Ujj, Laszlo; Royappa, Tim

    2011-03-01

    The liquid crystal 4'octyl-4-cyanobiphenyl (8CB) doped with cadmium selenide nanoparticles (Sigma-Aldrich) was injected into a commercially available liquid crystal cell (INSTEC, Inc). The cell was housed in a temperature controlled environment constructed in the lab and exposed to light from a frequency doubled pulsed Nd: YAG laser. The decay of fluorescence from the sample was measured at several temperatures over the range 25circ; to 45circ; C, covering the smectic-nematic and nematic-isotropic phase transitions. The sample was held at each temperature with a stability and resolution of 1mK before taking the measurement. The fluorescence was detected using a high-speed detector and the decay was measured using a boxcar averager. With the temperature control available, it was possible to approach very close to the phase transitions, with milliKelvin resolution. The results show a significant change in the decay of fluorescence near the nematic-isotropic phase transition.

  15. Collapse dynamics of liquid bridges investigated by time-varying magnetic levitation

    Science.gov (United States)

    Mahajan; Tsige; Zhang; Alexander; Taylor; Rosenblatt

    2000-01-10

    Using a novel technique that facilitates temporal control over the total body force on a liquid, an unexpected scaling relationship was discovered for the collapse time of a liquid bridge. A paramagnetic liquid was suspended between the tips of two collinear rods in a strong magnetic field gradient that was adjusted to compensate gravity. A sudden change of the magnet current, corresponding to a change of Bond number, resulted in a deformation and ultimate collapse of the liquid bridge. The collapse time was found to be independent of the bridge length when other parameters were held constant.

  16. Liquid/liquid heat exchanger

    Science.gov (United States)

    Miller, C. G.

    1980-01-01

    Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.

  17. Final prototype of magnetically suspended flywheel energy storage system

    Science.gov (United States)

    Anand, D. K.; Kirk, J. A.; Zmood, R. B.; Pang, D.; Lashley, C.

    1991-01-01

    A prototype of a 500 Wh magnetically suspended flywheel energy storage system was designed, built, and tested. The authors present the work done and include the following: (1) a final design of the magnetic bearing, control system, and motor/generator, (2) construction of a prototype system consisting of the magnetic bearing stack, flywheel, motor, container, and display module, and (3) experimental results for the magnetic bearings, motor, and the entire system. The successful completion of the prototype system has achieved: (1) manufacture of tight tolerance bearings, (2) stability and spin above the first critical frequency, (3) use of inside sensors to eliminate runout problems, and (4) integration of the motor and magnetic bearings.

  18. Suspended sediment in a high-Arctic river

    DEFF Research Database (Denmark)

    Ladegaard-Pedersen, Pernille; Sigsgaard, Charlotte; Kroon, Aart

    2017-01-01

    Quantifying fluxes of water, sediment and dissolved compounds through Arctic rivers is important for linking the glacial, terrestrial and marine ecosystems and to quantify the impact of a warming climate. The quantification of fluxes is not trivial. This study uses a 8-years data set (2005......-2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias corrected rating curves......-daily sampling together with a sampling frequency of 2h during extreme events. The most consistent estimation method was an uncorrected rating curve of bi-daily measurements (M2), combined with a linear interpolation of extreme event fluxes. Sampling can be reduced to every fourth day, with both method...

  19. Fluorine and sulfur simultaneously co-doped suspended graphene

    Science.gov (United States)

    Struzzi, C.; Sezen, H.; Amati, M.; Gregoratti, L.; Reckinger, N.; Colomer, J.-F.; Snyders, R.; Bittencourt, C.; Scardamaglia, M.

    2017-11-01

    Suspended graphene flakes are exposed simultaneously to fluorine and sulfur ions produced by the μ-wave plasma discharge of the SF6 precursor gas. The microscopic and spectroscopic analyses, performed by Raman spectroscopy, scanning electron microscopy and photoelectron spectromicroscopy, show the homogeneity in functionalization yield over the graphene flakes with F and S atoms covalently bonded to the carbon lattice. This promising surface shows potential for several applications ranging from biomolecule immobilization to lithium battery and hydrogen storage devices. The present co-doping process is an optimal strategy to engineer the graphene surface with a concurrent hydrophobic character, thanks to the fluorine atoms, and a high affinity with metal nanoparticles due to the presence of sulfur atoms.

  20. Heat Transfer Correlations for Free Convection from Suspended Microheaters

    Directory of Open Access Journals (Sweden)

    David GOSSELIN

    2016-08-01

    Full Text Available Portability and autonomy for biomedical diagnostic devices are two rising requirements. It is recognized that low-energy heating of such portable devices is of utmost importance for molecular recognition. This work focuses on screen-printed microheaters based on on Joule effect, which constitute an interesting solution for low-energy heating. An experimental study of the natural convection phenomena occurring with such microheaters is conducted. When they are suspended in the air, and because of the thinness of the supporting film, it is shown that the contributions of both the upward and downward faces have to be taken into account. A total Nusselt number and a total convective heat transfer coefficient have been used to describe the natural convection around these microheaters. In addition a relation between the Nusselt number and the Rayleigh number is derived, leading to an accurate prediction of the heating temperature (MRE< 2 %.

  1. Giant magneto-photoelectric effect in suspended graphene

    Science.gov (United States)

    Sonntag, Jens; Kurzmann, Annika; Geller, Martin; Queisser, Friedemann; Lorke, Axel; Schützhold, Ralf

    2017-06-01

    We study the optical response of a suspended, monolayer graphene field-effect transistor structure in magnetic fields of up to 9 T (quantum Hall regime). With an illumination power of only 3 μW, we measure a photocurrent of up to 400 nA (without an applied bias) corresponding to a photo-responsivity of 0.13 A W-1, which we believe to be one of the highest values ever measured in single-layer graphene. We discuss possible mechanisms for generating this strong photo-response (17 electron-hole pairs per 100 incident photons). Based on our experimental findings, we believe that the most likely scenario is a ballistic two-stage process including carrier multiplication via Auger-type inelastic Coulomb scattering at the graphene edge.

  2. Magneto-optical Faraday effect in suspended core micro-structured optical fiber filled with magnetic CoFe2O4 nanoparticles doped composite material

    Science.gov (United States)

    Jamon, D.; Marin, E.; Neveu, S.; Blanc-Mignon, M.-F.; Royer, F.

    2017-11-01

    This paper deals with the study of the magneto-optical Faraday effect of micro-structured optical fibers with suspended cores covered by a silica matrix doped by CoFe2O4 nanoparticles. Two different size distributions of nanoparticles originated from two magnetic fluids have been used to dope a sol-gel preparation later introduced in the fiber. Faraday rotation measurements were performed in liquid state, thin film and finally in the fiber in guided configuration. The two different magnetic behaviors of these nanoparticles collections allow us to evidence the Faraday effect of the micro-structured optical fiber.

  3. Near bed suspended sediment flux by single turbulent events

    Science.gov (United States)

    Amirshahi, Seyed Mohammad; Kwoll, Eva; Winter, Christian

    2018-01-01

    The role of small scale single turbulent events in the vertical mixing of near bed suspended sediments was explored in a shallow shelf sea environment. High frequency velocity and suspended sediment concentration (SSC; calibrated from the backscatter intensity) were collected using an Acoustic Doppler Velocimeter (ADV). Using quadrant analysis, the despiked velocity time series was divided into turbulent events and small background fluctuations. Reynolds stress and Turbulent Kinetic Energy (TKE) calculated from all velocity samples, were compared to the same turbulent statistics calculated only from velocity samples classified as turbulent events (Reevents and TKEevents). The comparison showed that Reevents and TKEevents was increased 3 and 1.6 times, respectively, when small background fluctuations were removed and that the correlation with SSC for TKE could be improved through removal of the latter. The correlation between instantaneous vertical turbulent flux (w ‧) and SSC fluctuations (SSC ‧) exhibits a tidal pattern with the maximum correlation at peak ebb and flood currents, when strong turbulent events appear. Individual turbulent events were characterized by type, strength, duration and length. Cumulative vertical turbulent sediment fluxes and average SSC associated with individual turbulent events were calculated. Over the tidal cycle, ejections and sweeps were the most dominant events, transporting 50% and 36% of the cumulative vertical turbulent event sediment flux, respectively. Although the contribution of outward interactions to the vertical turbulent event sediment flux was low (11%), single outward interaction events were capable of inducing similar SSC ‧ as sweep events. The results suggest that on time scales of tens of minutes to hours, TKE may be appropriate to quantify turbulence in sediment transport studies, but that event characteristics, particular the upward turbulent flux need to be accounted for when considering sediment transport

  4. Net transport of suspended matter due to tidal straining

    Science.gov (United States)

    Jones, S. E.; Jago, C. F.; Simpson, J. H.; Rippeth, T. P.

    2003-04-01

    Net transport of suspended particulate matter (SPM) is well-known in tidal regions where there is time-velocity asymmetry due to frictional modification of the tide in shallow water. We present here observations which show a new mechanism for net flux of SPM in response to tidal straining in a region of freshwater influence (ROFI). In situ measurements of the particle size of suspended particulate matter (SPM) and turbulent energy dissipation have been made at a site in Liverpool Bay (Irish Sea) where there is significant resuspension of particles from the muddy sand substrate during spring tides. This is a ROFI where tidal straining dominates the temporal development of turbulence. On a spring tide the water column tries to stratify on the ebb and destratify on the flood, but these tendencies are masked by mixing due to tidal stirring. Nevertheless, there is a marked excess of TKE dissipation rate E on the flood, especially in the upper part of the water column. Resuspension occurs on both flood and ebb, but SPM flux is strongly asymmetric with a net shorewards component. Asymmetry is most pronounced for the larger particles which comprise most of the mass. Enhanced ? on the flood mixes large particles upwards into faster flowing water, which increases the flux. Comparable upwards mixing of large particles does not occur on the ebb where enhanced E is confined to slower bottom waters. The net flux is not seen on neap tides because, although there is more stratification due to tidal straining, there is essentially no resuspension. The net flux on springs is undoubtedly an important component of SPM transport (and any comparable particulates) in coastal regions.

  5. Liquid helium

    CERN Document Server

    Atkins, K R

    1959-01-01

    Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.

  6. Diagnostic parameters in liquid-based cervical cytology using a coagulant suspension fixative

    NARCIS (Netherlands)

    Boon, ME; Ouwerkerk-Noordam, E; Suurmeijer, AH; Kok, LP

    2005-01-01

    Objective To evaluate in detail the morphology of cervical cell samples suspended in the coagulant fixative BoonFix (R) (Finetec, Tokyo, Japan) in liquid-based Papspin (R) slides (Thermo Shandon, Pittsburgh, Pennsylvania, U.S.A) to detect shifts in diagnostic parameters for infections and neoplasia.

  7. 76 FR 6462 - Notice of Intent To Suspend Certain Pesticide Registrations

    Science.gov (United States)

    2011-02-04

    ... hearing is made by a person adversely affected by the Notice of Intent to Suspend or the registrant has... this notice (i.e., how to request a hearing or how to comply fully with the requirements that served as... name notice of intent No. to suspend The Fountainhead Group, Inc.... Resmethrin 53853-1 Burgess Insect...

  8. 19 CFR 351.222 - Revocation of orders; termination of suspended investigations.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Revocation of orders; termination of suspended investigations. 351.222 Section 351.222 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE... orders; termination of suspended investigations. (a) Introduction. “Revocation” is a term of art that...

  9. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    NARCIS (Netherlands)

    Shen, F.; Verhoef, W.; Zhou, Y.; Salama, M.S.; Liu, X.

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of

  10. 75 FR 60720 - Antidumping or Countervailing Duty Order, Finding, or Suspended Investigation; Advance...

    Science.gov (United States)

    2010-10-01

    ... Goldberger, (202) 482-4136. from South Korea (A-580-836) (2rd Review). Granular Polytetrafluoroethylene Resin... South Korea (C-580-837) (2rd Review). Suspended Investigations No Sunset Review of suspended...; Advance Notification of Sunset Reviews AGENCY: Import Administration, International Trade Administration...

  11. Mechanical properties of freely suspended semiconducting graphene-like layers based on MoS2

    NARCIS (Netherlands)

    Castellanos-Gomez, A.; Poot, M.; Steele, G.A.; Van der Zant, H.S.J.; Agrait, N.; Rubio-Bollinger, G.

    2012-01-01

    We fabricate freely suspended nanosheets of molybdenum disulphide (MoS2) which are characterized by quantitative optical microscopy and high-resolution friction force microscopy. We study the elastic deformation of freely suspended nanosheets of MoS2 using an atomic force microscope. The Young’s

  12. Cricket inspired sensory hairs on suspended membranes with capacitive displacement detection

    NARCIS (Netherlands)

    van Baar, J.J.J.; Dijkstra, Marcel; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

    2004-01-01

    This paper presents the fabrication of artificial hairs of siliconnitride and SU-8 on suspended membranes for flow sensing applications. The suspended membranes contain electrodes for capacitive sensing of the rotation of the hairs. For the siliconnitride hairs a silicon wafer is used as mould and

  13. High suspended solids as a factor in reproductive failure of a freshwater mussel

    Science.gov (United States)

    Andrew M. Gascho-Landis; Wendell R. Haag; James A. Stoeckel

    2013-01-01

    Elevated suspended solids are a widespread stressor of aquatic ecosystems, but their effects on growth and reproduction in freshwater mussels are largely unknown. We fertilized experimental ponds to create a gradient in total suspended solids (TSS) and examined the effects of TSS on growth, nutritional status, reproduction, and clearance rate in Ligumia subrostrata....

  14. 76 FR 28730 - Notice of Intent To Suspend the Agricultural Labor Survey and Farm Labor Reports

    Science.gov (United States)

    2011-05-18

    ... National Agricultural Statistics Service Notice of Intent To Suspend the Agricultural Labor Survey and Farm Labor Reports AGENCY: National Agricultural Statistics Service, USDA. ACTION: Notice of suspension of... Agricultural Statistics Service (NASS) to suspend a currently approved information collection, the Agricultural...

  15. Physical and biological changes of suspended particles in a free surface flow constructed wetland

    NARCIS (Netherlands)

    Mulling, B.T.M.; van den Boomen, R.M.; Claassen, T.H.L.; van der Geest, H.G.; Kappelhof, J.W.N.M.; Admiraal, W.

    2013-01-01

    Suspended particles are considered as contaminants in treated wastewater and can have profound effects on the biological, physical and chemical properties of receiving aquatic ecosystems, depending on the concentration, type and nature of the suspended particles. Constructed wetlands are known to

  16. Quantitative suspended sediment mapping using aircraft remotely sensed multispectral data. [in Virginia

    Science.gov (United States)

    Johnson, R. W.

    1975-01-01

    Suspended sediment is an important environmental parameter for monitoring water quality, water movement, and land use. Quantitative suspended sediment determinations were made from analysis of aircraft remotely sensed multispectral digital data. A statistical analysis and derived regression equation were used to determine and plot quantitative suspended sediment concentration contours in the tidal James River, Virginia, on May 28, 1974. From the analysis, a single band, Band 8 (0.70-0.74 microns), was adequate for determining suspended sediment concentrations. A correlation coefficient of 0.89 was obtained with a mean inaccuracy of 23.5 percent for suspended sediment concentrations up to about 50 mg/l. Other water quality parameters - secchi disc depth and chlorophyll - also had high correlations with the remotely sensed data. Particle size distribution had only a fair correlation with the remotely sensed data.

  17. Tracing suspended sediment sources in the Upper Sangamon River Basin using fingerprinting techniques

    Science.gov (United States)

    Yu, M.; Rhoads, B. L.; Neal, C.; Anders, A. M.

    2014-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook and Wildcat Slough sub-watersheds from six potential sources: row-crop agriculture, forest, floodplains, river banks, pastures, and grasslands. Event-based suspended sediment samples were collected by in situ suspended sediment samplers and ISCO automatic pump samplers from the streams. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an unmixing model, was employed to estimate the relative contributions of sediment from six potential sources to the suspended sediment loads. Our preliminary results indicate that the majority of suspended sediment is derived from channel banks and forest adjacent to meandering reaches in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland areas adjacent to channelized rivers in the low

  18. The electro-optical characteristics of liquid crystal device in multi-component liquid crystal mixture system with non-contact photo-induced vertical alignment mode

    Science.gov (United States)

    Lin, Fa-Hsin; Ho, Czung-Yu; Lee, Jiunn-Yih

    2012-05-01

    In previous studies, we mixed photo-curable acrylic pre-polymer into negative dielectric anisotropy nematic type liquid crystal (N-type LC, NLC) to obtain a NLC/photo-curable acrylic pre-polymer mixture solution (NLC mixture system). After irradiation with UV light of fixed intensity, we successfully fabricated copolymer films with vertical alignment effect among the LC molecules. In this study, we propose a new type of multi-component LC mixture system by mixing chiral smectic type (SmA*) LC with homeotropic texture into NLC/photo-curable acrylic pre-polymer mixture system (NSLC mixture system). Our experimental results revealed that this SmA* LC exhibited the vertical alignment effect associated with LC molecules in the auxiliary LC mixture system. Moreover, we also discovered that altering the main chain type biphenol acrylic pre-polymer had drastic impact on the contrast ratio (CR) of the LC mixture system, with an increase of as much as 73%. More importantly, adding the SmA* LC can evidently increase the anchoring energy of the alignment film surface. We also further performed measurements, analyses, and discussions of electro-optical properties of devices fabricated from the new LC mixture systems.

  19. Conductance and dielectric anisotropy properties of 4-cyano-4'-hexylbiphenyl-salicylaldimine compound composite liquid crystal exhibiting large positive dielectric anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Yakuphanoglu, F. [Department of Physics, Firat University, 23169 Elazig (Turkey)]. E-mail: fyhan@hotmail.com; Bilgin-Eran, B. [Department of Chemistry, Yildiz Technical University, Davutpasa Yerlesim Birimi, TR-34210 Esenler, Istanbul (Turkey); Ocak, H. [Department of Chemistry, Yildiz Technical University, Davutpasa Yerlesim Birimi, TR-34210 Esenler, Istanbul (Turkey); Oweimreen, G.A. [Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2007-04-30

    The electronic properties of 4-cyano-4'-hexylbiphenyl and salicylaldimine compound 1 liquid crystals have been investigated. The polarizing microscopy and differential scanning calorimetry results show that chiral salicylaldimine compound 1 exhibits enantiotropic smectic A* and SmC* mesophases. The novel 4-n-hexyl-4'-cyanobiphenyl/salicylaldimine compound 1 composite showed an extremely large positive dielectric anisotropy. The dielectric anisotropy of the LCs changes from positive type to negative type. The critical frequency f {sub c} values of dielectrical anisotropy for 4-n-hexyl-4'-cyanobiphenyl and salicylaldimine compound 1 LCs were found to be 630.50 and 813.01 kHz, respectively. The splay elastic constant K {sub 11} values of the liquid crystals were calculated and the doping of salicylaldimine compound 1 into 4-cyano-4'-hexylbiphenyl liquid crystal increases the splay elastic constant of 6CB. The parallel conductivity {sigma} {sub -}parallel values of the liquid crystals are higher than that of perpendicular conductivity {sigma} {sub -}perpendicular values and conductivity of the 4-cyano-4'-hexylbiphenyl decreases with doping of salicylaldimine compound 1.

  20. Quantification of suspended sediment transfers in a lowland agricultural catchment

    Science.gov (United States)

    Salvador-Blanes, Sebastien; Manière, Louis; Grangeon, Thomas; Cerdan, Olivier; Evrard, Olivier; Foucher, Anthony; Vandromme, Rosalie

    2017-04-01

    Lowland agricultural landscapes underwent important changes since the second half of the XXth century such as hedges removal, implementation of drainage systems, stream redesign and land reallocation. It resulted in changes in sediment transfer processes, and in widespread morphological alterations of water bodies. However, little is known about the sediment dynamics in these environments. The Louroux catchment (25 km2) is located in central France. It is a typical intensively cultivated and tile drained lowland catchment. The Xth century pond located at its outlet (52 ha) is undergoing large siltation, with a current sedimentation rate 60 fold higher than the pre-1950 period. Five monitoring stations, measuring water levels and turbidity at high frequency (15 mn and 1 mn respectively), combined with automatic samplers, were implemented in 2013. Three stations are located at the main tributaries outlets of the pond, one in a sub-catchment, and one at a tile drain outlet. 45 floods were observed during the three studied hydrological years. They occurred mostly between December and March (33 floods) and in May-June (8 floods). Specific sediment yields ranged from 0.02 to 0.38 t.ha-1.yr-1 depending on the monitoring site and the considered year. The vast majority of suspended sediment transfers occur during the winter floods. While large water volumes were also measured during spring floods, the sediment yields remained low. Suspended sediment yields present large inter-annual (ratio ranging between 2 and 6 depending on the monitoring station) and spatial variations, due to significant differences in total rainfall amounts during the winter season and variations in land use, respectively. The processes related to sediment transfers are most likely linked to soil saturation during winter despite the presence of a tile drainage network, with transfers occurring both at the soil surface and through the drainage system. While sediment transfer rates can be considered as

  1. Unified theory of non-suspended sediment transport mediated by a Newtonian fluid

    Science.gov (United States)

    Pähtz, Thomas; Durán, Orencio

    2017-04-01

    We present a unified theory of steady, homogeneous, non-suspended transport of nearly uniform spheres mediated by an arbitrary Newtonian fluid. The theory consists of elements that are rigorously derived from Newton's axioms and of semi-empirical elements that well describe simulation data, obtained using a coupled DEM/RANS numerical model of sediment transport in a Newtonian fluid (Durán et al., POF 103306, 2012), for the entire simulated range of the particle-fluid-density ratio s=ρ_p/ρ_f, particle Reynolds number Re_p=√{(s-1)gd^3}/ν, and Shields number Θ=τ/[(ρ_p-ρ_f)gd], where g is the gravitational constant, d the mean particle diameter, and ν the kinematic viscosity. The theory takes into account our recent numerical finding that the mode of entrainment of bed sediment is controlled by the `impact number' Im=Re_p√{s+0.5} (https://arxiv.org/abs/1605.07306), with entrainment through particle-bed impacts dominating most conditions (including turbulent bedload transport). Despite not being fitted to experimental data, the theory simultaneously reproduces measurements in air (s≈2100) and liquids (s≈1{-}5) of the transport cessation threshold Θ^ext (https://arxiv.org/abs/1602.07079), obtained from extrapolation to vanishing transport, and the dimensionless value Q^\\ast=Q/(ρ_p√{(s-1)gd^3}) of the sediment transport rate Q. From the theory and simulations, we learn that considering added-mass, lubrication, fluid lift, and/or history forces is not required to quantitatively reproduce measurements. However, collisions between transported particles cannot be neglected as they are strongly influencing the scaling of Q_\\ast with Θ. We find such collisions are behind the asymptotic scaling Q_\\ast∝Θ^3Rep measured for transport in viscous liquids and also indirectly behind a transition from a linear scaling Q_\\ast∝√{Θ^ex_t}(Θ-Θ^ex_t) to a non-linear scaling Q_\\ast∝√{Θ}(Θ-Θ^ex_t) of the transport rate in turbulent bedload and

  2. Tidal influence on suspended sediment distribution and dispersal in the northern Andaman Sea and Gulf of Martaban

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Rao, P.S.; Rao, K.H.; Thwin, S.; Rao, N.S.; Raiker, V.

    Surface and water column profiles of suspended matter collected during April-May 2002, and satellite images were used to study factors influencing suspended sediment concentrations (SSCs) and dispersal in the northern Andaman Sea and Gulf...

  3. Characterization of ammonia volatilization from liquid dairy manure

    Science.gov (United States)

    Koirala, Kedar

    Emission of gases, odor, and particulate matters from livestock manure is a major concern because of their potential adverse environmental impacts. For example, ammonia in the air has the potential to: negatively affect animal, human health and environment. Mitigation of ammonia emissions from livestock manure to protect animal and human health, and the environment, in general, is thus an important agenda for livestock producers, engineers, and environmental scientists. Proper understanding of the mechanisms or process of its volatilization from manure is the first step towards designing or formulating appropriate emissions mitigation strategies. This research investigated the effects of suspended solids, anaerobic digestion, and ionic strength on the ammonia (NH3) volatilization mechanism from liquid dairy manure. Experiments were conducted to: (i) assess the role of suspended solids characteristics on ammonia volatilization, (ii) evaluate the impacts of anaerobic digestion on the process governing NH 3 volatilization, and (iii) delineate the influences of suspended solids (SS) and ionic strength (IS) on the ammonia volatilization process from dairy manure. Two key parameters (the ammonia dissociation and the overall mass transfer coefficient (KoL)) that govern ammonia volatilization were evaluated to achieve these objectives. The physical and chemical properties of manure were also evaluated to further elucidate the respective processes. The suspended solids ammoniacal nitrogen adsorption properties did not significantly affect either the ammonium dissociation or the K oL; suggesting that the characteristics of manure suspended solids did not play a significant role in ammonia volatilization from liquid dairy manure. The dissociation of ammonium in anaerobically digested (AD) manure was significantly higher than in the undigested (UD) manure. However, KoL was less in AD manure than in UD manure, while an increase in total ammoniacal nitrogen (TAN) was observed

  4. Salinity and suspended matter variations in the Tay estuary

    Science.gov (United States)

    McManus, John

    2005-03-01

    The concept of salinity-induced density layering in estuaries was first demonstrated from the upper reaches of the Tay. In this study the nature of the layering and its variation through the tidal cycle is demonstrated from time series of observations taken at many locations within this estuary. Thorough mixing of the waters on the rising tide, as defined by depth profiles of salinity, is commonly replaced by salinity layering during the high water slack period. This condition continues into the falling tide. Frequently the mixed waters are abruptly replaced by stratified waters within the half-hourly sampling interval. This is attributed to the activity of longitudinal fronts, manifest as surficial foam bands, along which water masses shear past each other on both the flood and ebb tides. Offsetting of transverse salinity coutours along the fronts is introduced to explain apparent complexities in surface water salinity distributions measured at high water slack. Suspended particulate matter concentrations increase towards the limit of the saline water intrusion before decreasing headwards into the freshwater zone of the estuary. The suspensions in the water column may also be displaced by the lateral offsetting of the waters along the fronts. The recognition of the presence of fronts, and a knowledge of their impact on the estuarine waters may provide an alternative means of understanding the flow characteristics of these challenging water bodies. The techniques of spatial and temporal averaging normally widely used today may not be the most realistic approach to analysis of the flows.

  5. High-field electrical and thermal transport in suspended graphene.

    Science.gov (United States)

    Dorgan, Vincent E; Behnam, Ashkan; Conley, Hiram J; Bolotin, Kirill I; Pop, Eric

    2013-10-09

    We study the intrinsic transport properties of suspended graphene devices at high fields (≥1 V/μm) and high temperatures (≥1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6 × 10(7) cm/s (1.7 × 10(7) cm/s) and peak (average) thermal conductivity of 530 W m(-1) K(-1) (310 W m(-1) K(-1)) at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions.

  6. Elemental Spatiotemporal Variations of Total Suspended Particles in Jeddah City

    Directory of Open Access Journals (Sweden)

    Mohammad W. Kadi

    2014-01-01

    Full Text Available Elements associated with total suspended particulate matter (TSP in Jeddah city were determined. Using high-volume samplers, TSP samples were simultaneously collected over a one-year period from seven sampling sites. Samples were analyzed for Al, Ba, Ca, Cu, Mg, Fe, Mn, Zn, Ti, V, Cr, Co, Ni, As, and Sr. Results revealed great dependence of element contents on spatial and temporal variations. Two sites characterized by busy roads, workshops, heavy population, and heavy trucking have high levels of all measured elements. Concentrations of most elements at the two sites exhibit strong spatial gradients and concentrations of elements at these sites are higher than other locations. The highest concentrations of elements were observed during June–August because of dust storms, significant increase in energy consumption, and active surface winds. Enrichment factors of elements at the high-level sites have values in the range >10~60 while for Cu and Zn the enrichment factors are much higher (~0–>700 indicating that greater percentage of TSP composition for these three elements in air comes from anthropogenic activities.

  7. Deterministic separation of suspended particles in a reconfigurable obstacle array

    CERN Document Server

    Du, Siqi

    2015-01-01

    We use a macromodel of a flow-driven deterministic lateral displacement (DLD) microfluidic system to investigate conditions leading to size-separation of suspended particles. This model system can be easily reconfigured to establish an arbitrary orientation between the average flow field and the array of obstacles comprising the stationary phase (forcing angle). We also investigate the effect of obstacle size using two arrays with different obstacles but same surface-to-surface distance between them. In all cases, we observe the presence of a locked mode at small forcing angles, in which particles move along a principal direction in the lattice until a locked-to-zigzag transition takes place when the driving force reaches a critical angle. We show that the transition occurs at increasing angles for larger particles, thus enabling particle separation at specific forcing angles. Moreover, we observe a linear correlation between the critical angle and the size of the particles that could be used in the design of...

  8. Remote Sensing of Suspended Sediment Over Gulf of Martaban

    Directory of Open Access Journals (Sweden)

    Matamin Abd Rahman

    2015-03-01

    Full Text Available Gulf of Martaban is located at the north of Andaman, and is one of the world most turbid areas. The presence of suspended sediment concentration (SSC in the water body could reduce the underwater transmittance. This study has been conducted to investigate the variation of SSC over the Gulf of Martaban. Remote sensing reflectance (Rrs of 667 nm is used as a proxy to represent the sediment SSC variation over the study area. The data for the period of July 2002 to March 2014 acquired from MODIS Aqua 4 km resolution are used in this study. As a result, there is no obvious yearly variation in the SSC cover area. The SSC variation over this study area is found to be seasonal. High homogenous SSC covers area observably during the northeast (NE monsoon season that occurs from December to January. The sediment cover area could reach the latitude of 15°N that located at the south of the gulf. During southwest (SW monsoon season that occurs from May to September, low and sparse SSC cover area is observed. As a consequence, the area covered by the SSC is higher during the NE monsoon season as compared to the SW monsoon season. Hence, the SSC cover area during the NE monsoon season is greater than the yearly averaged SSC cover area. Meanwhile the SSC cover area during the rainy SW monsoon season is less than the yearly and NE monsoon season.

  9. Ensemble Modeling of Suspended Sediment in Steep Mountain Catchments

    Science.gov (United States)

    Stewart, J.; Raseman, W. J.; Kasprzyk, J. R.; Livneh, B.

    2016-12-01

    Climatic and land cover changes present important uncertainties into the rates of soil erosion and sedimentation in watersheds. Soil erosion adds constituents to streams, altering water chemistry and streambed morphology, which can adversely affect aquatic life and poses a critical challenge for water treatment and reservoir management. The goal of this research is to establish estimates of sediment transport within large-scale mountainous catchments (>1000 km2). As sedimentation rates are impacted by numerous physical processes including soil, land cover, slope and climate; the results from seven models will be presented to quantify uncertainty and improve predictability. A broader inquiry made here is into the efficacy of model structure under different conditions. We present the results from empirical, stochastic, conceptual and physical models. These include empirical models: monovariate rating curve, multivariate regression and the Modified Universal Soil Loss Equation (MUSLE), to models with conceptual components: Soil Water Assessment Tool (SWAT) to more physically based models: Water Erosion Prediction Project (WEPP), Precipitation Runoff Modeling System (PRMS) and Distributed Hydrology Soil Vegetation Model (DHSVM). Key uncertainties will be characterized resulting from forcing inputs, parameter selection, scale discretization, and model structure. Calibration results from a multi-objective optimization routine will be presented that optimize parameters and identify performance trade-offs that will be used to develop uncertainty estimates in both streamflow and sediment projections. The outcomes of this research will highlight critical issues relevant to large-scale hydrologic and suspended sediment prediction initiatives.

  10. Event-based total suspended sediment particle size distribution model

    Science.gov (United States)

    Thompson, Jennifer; Sattar, Ahmed M. A.; Gharabaghi, Bahram; Warner, Richard C.

    2016-05-01

    One of the most challenging modelling tasks in hydrology is prediction of the total suspended sediment particle size distribution (TSS-PSD) in stormwater runoff generated from exposed soil surfaces at active construction sites and surface mining operations. The main objective of this study is to employ gene expression programming (GEP) and artificial neural networks (ANN) to develop a new model with the ability to more accurately predict the TSS-PSD by taking advantage of both event-specific and site-specific factors in the model. To compile the data for this study, laboratory scale experiments using rainfall simulators were conducted on fourteen different soils to obtain TSS-PSD. This data is supplemented with field data from three construction sites in Ontario over a period of two years to capture the effect of transport and deposition within the site. The combined data sets provide a wide range of key overlooked site-specific and storm event-specific factors. Both parent soil and TSS-PSD in runoff are quantified by fitting each to a lognormal distribution. Compared to existing regression models, the developed model more accurately predicted the TSS-PSD using a more comprehensive list of key model input parameters. Employment of the new model will increase the efficiency of deployment of required best management practices, designed based on TSS-PSD, to minimize potential adverse effects of construction site runoff on aquatic life in the receiving watercourses.

  11. Design of Experimental Suspended Footbridge with Deck Made of UHPC

    Directory of Open Access Journals (Sweden)

    Blank Marek

    2016-01-01

    Full Text Available This paper deals with the static and dynamic design of experimental footbridge for pedestrians and cyclists in the municipality Lužec nad Vltavou in Czech Republic, Europe. This work aims to familiarize the reader with calculations carried out and the results obtained, describing the static and dynamic properties of proposed footbridge. The construction of footbridge is designed as a suspended structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tons. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings. The utilization of the excellent properties of UHPC allows to design a very thin and lightweight construction of the deck, which could not be achieved with the use of normal concrete.

  12. Suspended sediment dynamics in the Amazon River of Peru

    Science.gov (United States)

    Armijos, Elisa; Crave, Alain; Vauchel, Philippe; Fraizy, Pascal; Santini, William; Moquet, Jean-Sèbastien; Arevalo, Nore; Carranza, Jorge; Guyot, Jean-Loup

    2013-07-01

    The erosion and transport of sediments allow us to understand many activities of significance, such as crust evolution, climate change, uplift rates, continental processes, the biogeochemical cycling of pollutants and nutrients. The Amazon basin of Peru has contrasting physiographic and climatic characteristics between the Andean piedmont and the plains and between the north and south of the basin which is why there are 8 gauging stations located along the principal rivers of the Andean piedmont (Marañón, Huallaga, Ucayali) and the plain (Marañón, Tigre, Napo, Ucayali and Amazon rivers). Since 2003, the ORE-Hybam (IRD-SENAMHI-UNALM) observatory has performed out regular measurements at strategic points of the Amazon basin to understand and model the systems, behavior and long-term dynamics. On the Andean piedmont, the suspended yields are governed by a simple model with a relationship between the river discharge and the sediment concentration. In the plain, the dilution effect of the concentrations can create hysteresis in this relationship on a monthly basis. The Amazon basin of Peru has a sediment yield of 541 *106 t year-1, 70% comes from the southern basin.

  13. Freely suspended nanocomposite membranes as highly sensitive sensors.

    Science.gov (United States)

    Jiang, Chaoyang; Markutsya, Sergiy; Pikus, Yuri; Tsukruk, Vladimir V

    2004-10-01

    Highly sensitive sensor arrays are in high demand for prospective applications in remote sensing and imaging. Measuring microscopic deflections of compliant micromembranes and cantilevers is developing into one of the most versatile approaches for thermal, acoustic and chemical sensing. Here, we report on an innovative fabrication of compliant nanocomposite membranes with nanoscale thickness showing extraordinary sensitivity and dynamic range, which makes them candidates for a new generation of membrane-based sensor arrays. These nanomembranes with a thickness of 25-70 nm, which can be freely suspended over large (hundred micrometres) openings are fabricated with molecular precision by time-efficient, spin-assisted layer-by-layer assembly. They are designed as multilayered molecular composites made of a combination of polymeric monolayers and a metal nanoparticle intralayer. We demonstrate that these nanocomposite membranes possess unparalleled sensitivity and a unique autorecovering ability. The membrane nanostructure that is responsible for these outstanding properties combines multilayered polymer/nanoparticle organization, high polymer-chain orientation, and a pre-stretched state.

  14. Novel biphenyl-substituted 1,2,4-oxadiazole ferroelectric liquid crystals: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Mahabaleshwara Subrao

    2015-02-01

    Full Text Available Two novel series of unsymmetrically substituted 1,2,4-oxadiazole viz., R.Ox.C*Cn compounds are synthesized and characterized. An optically active, (S-(+-methyl 3-hydroxy-2-methylpropionate is used to introduce a chiral center in the molecule. A biphenyl moiety prepared by Suzuki coupling reaction is directly attached to the oxadiazole core at C-5 position. Investigations for the phase behavior revealed that the series with a benzyl group on one end of the oxadiazole core exhibits an 1D orthogonal smectic-A phase while the second series with dodecyl flexible end chain shows orthogonal smectic-A and tilted chiral smectic-C (SmC* phases over a wide range of temperatures. The smectic-C phase exhibits ferroelectric (FE polarization switching. The mesomorphic thermal stabilities of these compounds are discussed in the domain of the symmetry and the flexibility of the alkyloxy end chain length attached to the chiral center.

  15. Investigating suspended sediment dynamics in contrasting agricultural catchments using ex situ turbidity-based suspended sediment monitoring

    Science.gov (United States)

    Sherriff, S. C.; Rowan, J. S.; Melland, A. R.; Jordan, P.; Fenton, O.; hUallachain, D. O.

    2015-08-01

    Soil erosion and suspended sediment (SS) pose risks to chemical and ecological water quality. Agricultural activities may accelerate erosional fluxes from bare, poached or compacted soils, and enhance connectivity through modified channels and artificial drainage networks. Storm-event fluxes dominate SS transport in agricultural catchments; therefore, high temporal-resolution monitoring approaches are required, but can be expensive and technically challenging. Here, the performance of in situ turbidity sensors, conventionally installed submerged at the river bankside, is compared with installations where river water is delivered to sensors ex situ, i.e. within instrument kiosks on the riverbank, at two experimental catchments (Grassland B and Arable B). The in situ and ex situ installations gave comparable results when calibrated against storm-period, depth-integrated SS data, with total loads at Grassland B estimated at 12 800 and 15 400 t, and 22 600 and 24 900 t at Arable B, respectively. The absence of spurious turbidity readings relating to bankside debris around the in situ sensor and its greater security make the ex situ sensor more robust. The ex situ approach was then used to characterise SS dynamics and fluxes in five intensively managed agricultural catchments in Ireland which feature a range of landscape characteristics and land use pressures. Average annual suspended sediment concentration (SSC) was below the Freshwater Fish Directive (78/659/EEC) guideline of 25 mg L-1, and the continuous hourly record demonstrated that exceedance occurred less than 12 % of the observation year. Soil drainage class and proportion of arable land were key controls determining flux rates, but all catchments reported a high degree of inter-annual variability associated with variable precipitation patterns compared to the long-term average. Poorly drained soils had greater sensitivity to runoff and soil erosion, particularly in catchments with periods of bare soils. Well

  16. Optical devices having flakes suspended in a host fluid to provide a flake/fluid system providing flakes with angularly dependent optical properties in response to an alternating current electric field due to the dielectric properties of the system

    Science.gov (United States)

    Kosc, Tanya Z [Rochester, NY; Marshall, Kenneth L [Rochester, NY; Jacobs, Stephen D [Pittsford, NY

    2006-05-09

    Optical devices utilizing flakes (also called platelets) suspended in a host fluid have optical characteristics, such as reflective properties, which are angular dependent in response to an AC field. The reflectivity may be Bragg-like, and the characteristics are obtained through the use of flakes of liquid crystal material, such as polymer liquid crystal (PLC) materials including polymer cholesteric liquid crystal (PCLC) and polymer nematic liquid crystal (PNLC) material or birefringent polymers (BP). The host fluid may be propylene carbonate, poly(ethylene glycol) or other fluids or fluid mixtures having fluid conductivity to support conductivity in the flake/host system. AC field dependent rotation of 90.degree. can be obtained at rates and field intensities dependent upon the frequency and magnitude of the AC field. The devices are useful in providing displays, polarizers, filters, spatial light modulators and wherever switchable polarizing, reflecting, and transmission properties are desired.

  17. Aerial Photo Utilization in Estimating Suspended Sediment in the Wuryantoro Watershed, Wonogiri

    Directory of Open Access Journals (Sweden)

    Sugiharto Budi Santoso

    2004-01-01

    Full Text Available Suspended sediment load flowing out from a watershed is normally predicated by analysis os suspended sediment of water sample, and the volume of suspended sediment be calculated based on sediment concentration and river discharge. Such field measurements need a lot of field data and they are time consuming. Another method for prediction of suspended sediment by using remote sensing imagery data and recorded rainfall data. The objective of this research is to 1 examine the capability of remote sensing technique to obtain the parameters of the physical data of land in the prediction of suspended sediment; 2 examine the accuracy of the model for prediction suspended sediment. This research is carried out in Wuryantoro watershed, Wonogiri. The main data to obtain the parameters of the physical data of land is infrared aerial photograph on scale 1 : 10.000. the method that used in this research is interpretation of remote sensing imagery data, combined with rainfall data. The result show that the accuracy of landuse is 88.5%, the accuracy of slope is 87.67%. the accuracy of the prediction of suspended sediment by model A3 87.07%, model C1 86.63%, model C2 90.57%, model A8 84.13%, model A9 80.1%, and model C4 78.6%.

  18. High concentration suspended sediment measurments using acontinuous fiber optic in-stream transmissometer

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Chris G.; Laycak, Danny T.; Hoppes, William; Tran,Nguyen T.; Shi, Frank G.

    2004-05-26

    Suspended sediment loads mobilized during high flow periods in rivers and streams are largely uncharacterized. In smaller and intermittent streams, a large storm may transport a majority of the annual sediment budget. Therefore monitoring techniques that can measure high suspended sediment concentrations at semi-continuous time intervals are needed. A Fiber optic In-stream Transmissometer (FIT) is presented for continuous measurement of high concentration suspended sediment in storm runoff. FIT performance and precision were demonstrated to be reasonably good for suspended sediment concentrations up to 10g/L. The FIT was compared to two commercially available turbidity devices and provided better precision and accuracy at both high and low concentrations. Both turbidity devices were unable to collect measurements at concentrations greater than 4 g/L. The FIT and turbidity measurements were sensitive to sediment particle size. Particle size dependence of transmittance and turbidity measurement poses the greatest problem for calibration to suspended sediment concentration. While the FIT was demonstrated to provide acceptable measurements of high suspended sediment concentrations, approaches to real-time suspended sediment detection need to address the particle size dependence in concentration measurements.

  19. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: ben.kefford@rmit.edu.a [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)

    2010-02-15

    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  20. Suspended-sediment loads and reservoir sediment trap efficiency for Clinton Lake, Kansas, 2010-12

    Science.gov (United States)

    Juracek, Kyle E.

    2013-01-01

    Continuous streamflow and turbidity data collected from October 1, 2010, to September 30, 2012, at a site upstream and downstream from Clinton Lake, Kansas, were used to compute the total suspended-sediment load delivered to and released from the reservoir as well as the sediment trap efficiency for the reservoir. Ongoing sedimentation is inhibiting the ability of Clinton Lake to serve several purposes including flood control, water supply, and recreation. The inflow suspended-sediment load was substantially larger than the outflow load and most of the suspended-sediment load was delivered during short-term, high-discharge periods. Respectively, the total 2-year inflow and outflow suspended-sediment loads were computed to be 44.4 and 1.49 million pounds. Sediment trap efficiency for the reservoir was estimated to be 97 percent. The mean annual suspended-sediment yield from the upstream basin was estimated to be 60,500 pounds per square mile. Because this study was completed during a drought, the estimated inflow suspended-sediment load and suspended-sediment yield likely are substantially less than what would occur during a period of average or above average precipitation and runoff.

  1. Comparative study of manual liquid-based cytology (MLBC) technique and direct smear technique (conventional) on fine-needle cytology/fine-needle aspiration cytology samples

    OpenAIRE

    Prajkta Suresh Pawar; Rasika Uday Gadkari; Sunil Y Swami; Anil R Joshi

    2014-01-01

    Background: Liquid-based cytology technique enables cells to be suspended in a liquid medium and spread in a monolayer, making better morphological assessment. Automated techniques have been widely used, but limited due to cost and availability. Aim: The aim was to establish manual liquid-based cytology (MLBC) technique on fine-needle aspiration cytology (FNAC) material and compare its results with conventional technique. Materials and Methods: In this study, we examined cells trappe...

  2. Mucous Secretion and Cilia Beating Defend Developing Coral Larvae from Suspended Sediments.

    Directory of Open Access Journals (Sweden)

    Gerard F Ricardo

    Full Text Available Suspended sediments produced from dredging activities, or added to the sediment budget via river runoff, are a concern for marine resource managers. Understanding the impact of suspended sediments on critical life history stages of keystone species like corals is fundamental to effective management of coastlines and reefs. Coral embryos (Acropora tenuis and A. millepora and larvae (A. tenuis, A. millepora and Pocillopora acuta were subjected to a range of suspended sediment concentrations of different sediment types (siliciclastic and carbonate to assess concentration-response relationships on ecologically relevant endpoints, including survivorship and ability to metamorphose. Embryos were subjected to short (12 h suspended sediment exposures from ages of 3-12 hours old or a long (30 h exposure at 6 hours old. Neither the survivorship nor metamorphosis function of embryos were significantly affected by realistic sediment exposures to ~1000 mg L-1. However, some embryos exhibited a previously undescribed response to dynamically suspended sediments, which saw 10% of the embryos form negatively buoyant cocoons at siliciclastic suspended sediment concentrations ≥35 mg L-1. Scanning electron and optical microscopy confirmed the presence of a coating on these embryos, possibly mucus with incorporated sediment particles. Cocoon formation was common in embryos but not in larvae, and occurred more often after exposure to siliciclastic rather than carbonate sediments. Once transferred into sediment-free seawater, functional ~36-h-old embryos began emerging from the cocoons, coinciding with cilia development. Ciliated (> 36-h-old larvae exposed to suspended sediments for 60 h were also observed to secrete mucus and were similarly unaffected by suspended sediment concentrations to ~800 mg L-1. This study provides evidence that mucous secretion and cilia beating effectively protect coral embryos and larvae from suspended sediment and that these mechanisms

  3. 40 CFR 1042.330 - Selling engines from an engine family with a suspended certificate of conformity.

    Science.gov (United States)

    2010-07-01

    ... with a suspended certificate of conformity. 1042.330 Section 1042.330 Protection of Environment... engines from an engine family with a suspended certificate of conformity. You may sell engines that you produce after we suspend the engine family's certificate of conformity under § 1042.315 only if one of the...

  4. 5 CFR 1620.45 - Suspending TSP loans, restoring post-employment withdrawals, and reversing taxable distributions.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Suspending TSP loans, restoring post... Employment and Reemployment Rights Act (USERRA)-Covered Military Service § 1620.45 Suspending TSP loans, restoring post-employment withdrawals, and reversing taxable distributions. (a) Suspending TSP loans during...

  5. Determining annual suspended sediment and sediment-associated trace element and nutrient fluxes

    Science.gov (United States)

    Horowitz, A.J.

    2008-01-01

    Suspended sediment is a major factor in the biological and geochemical cycling of trace elements and nutrients in aquatic systems. The design of effective studies involving the collection, processing, and subsequent chemical analysis of suspended sediment requires a clear understanding of the problems associated with using this sample medium. This review summarizes the current state of knowledge relative to the various issues/problems associated with the collection of representative suspended sediment samples in fluvial systems. It also addresses issues associated with accurately determining the concentrations and fluxes of sediment-associated trace elements and nutrients.

  6. H2S induces a suspended animation-like state in mice.

    Science.gov (United States)

    Blackstone, Eric; Morrison, Mike; Roth, Mark B

    2005-04-22

    Mammals normally maintain their core body temperature (CBT) despite changes in environmental temperature. Exceptions to this norm include suspended animation-like states such as hibernation, torpor, and estivation. These states are all characterized by marked decreases in metabolic rate, followed by a loss of homeothermic control in which the animal's CBT approaches that of the environment. We report that hydrogen sulfide can induce a suspended animation-like state in a nonhibernating species, the house mouse (Mus musculus). This state is readily reversible and does not appear to harm the animal. This suggests the possibility of inducing suspended animation-like states for medical applications.

  7. Electromechanical coupling in suspended nanomechanical resonators with a two-dimensional electron gas

    Science.gov (United States)

    Shevyrin, A. A.; Pogosov, A. G.; Bakarov, A. K.; Shklyaev, A. A.

    2017-06-01

    A physical model describing the piezoelectric-effect-mediated influence of bending of a thin suspended cantilever with a two-dimensional electron gas on the conductivity is proposed. The model shows that the conductivity change is almost entirely caused by the rapid change in mechanical stress near the boundary of suspended and non-suspended areas, rather than by the stress itself. An experiment confirming that the electromechanical coupling is associated with the piezoelectric effect is performed. The experimentally measured conductance sensitivity to the cantilever’s vibrations agree with the developed physical model.

  8. Basic hydraulic experiment on the saturated concentration of suspended load due to tsunamis

    Science.gov (United States)

    Takahashi, Tomoyuki; Somekawa, Shiho

    2016-04-01

    When tsunamis arrive in the shallow sea, a huge amount of suspended load is generated by large velocity and strong turbulence. The suspended load causes the geomorphic processes of erosion and deposition. Because the suspended load cannot be increased endlessly, it should have the saturated concentration. Many numerical models of sediment transport due to tsunamis have assumed a constant value of 1% for the saturated concentration empirically. However, it is supposed as a function of velocity. In this study, a hydraulic experiment was carried out to investigate a relationship between velocity and the saturated concentration of suspended load when tsunamis attack. A water circulation pipe used in the experiment was 10 cm in a diameter, 260 cm in length and 50 cm in width. A velocity of water flow in the pipe had been controlled by two pumps and two valves. It was changed from 0.24 to 1.22 m/s. Various amounts of sand was spread on the bottom of pipe. The amount of sand was changed from 0.1 to 10% as converted in the concentration of suspended load if all sand suspended. A diameter and a density of the sand were 0.267 mm and 2.64 x 103 kg/m^3. A condition of sediment transport in the pipe was recorded by video camera from a transparent window at the side of pipe. The condition was judged as all sand particles were suspended or not. The former condition indicates that the concentration of suspended load is saturated and the latter does it is not saturated. When velocity was smaller than 0.47 m/s, there was no suspended load because of a weak tractive force. When velocity became larger, the suspended load was generated and the concentration also became higher. However, the concentration had the upper limit and surplus sand appeared on the bed of pipe when velocity became much larger. The condition gave the saturated concentration of suspended load. When velocity was 0.665 m/s, the saturated concentration was smaller than 1% which is used in many numerical simulations

  9. Self-assembly of gelator molecules in liquid crystals studied by ESR

    Energy Technology Data Exchange (ETDEWEB)

    Andreis, Mladen, E-mail: andreis@irb.hr [Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Caric, Dejana; Vujicic, Natasa Sijakovic; Jokic, Milan; Zinic, Mladen; Kveder, Marina [Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer The event of HCCA crystallization is strongly affected by the presence of gelator 1. Black-Right-Pointing-Pointer ESR technique detects the onset of gelator network self-assembly in nematic phase. Black-Right-Pointing-Pointer The melting of gelator network is studied in the heating cycle. -- Abstract: Thermotropic liquid crystal trans-4-heptylcyclohexanecarboxylic acid (HCCA) doped with 4-oxo-2,2,6,6,-tetramethyl-1-piperidinyloxy spin probe (Tempone) is investigated by electron spin resonance (ESR) spectroscopy in the presence of chiral bisoxalamide gelator 1 during both cooling and heating cycles. In the temperature range 295-383 K, where HCCA displays isotropic, nematic, smectic B and crystalline phases, the impact of 1 self-organization was detected via (non) homogeneous partitioning of the spin probe in the environments varying in the polarity, an effect dependent on the gelator concentration. In particular, the evidence of the onset of the gelator network self-assembly in the nematic phase was detected by ESR at higher temperatures than the ones reported so far by other experimental techniques. Additionally, the spectral analysis points to the switching of the polarity in the vicinity of the spin probe when the transfer of chirality from 1 to HCCA upon cooling of the sample from isotropic to chiral nematic phase appears and when the event of LC gelation results in the achiral nematic phase during chiral gel fibers formation. When the gelation proceeds in the smectic phase, the melting of the gelator network is studied in the nematic phase during the heating cycle. Furthermore, the event of HCCA crystallization is shown to be strongly affected by the presence of 1 as well. The experimental evidence is provided that gelator network confines the HCCA into the domains within the bulk crystalline matrix where the local molecular dynamics are still not frozen. Therefore, we propose that non-homogeneous polarity profile of

  10. Transferability of coarse-grained force field for nCB liquid crystal systems.

    Science.gov (United States)

    Zhang, Jianguo; Guo, Hongxia

    2014-05-01

    In this paper, the transferability of the coarse-grained (CG) force field originally developed for the liquid crystal (LC) molecule 5CB ( Zhang et al. J. Phys. Chem. B 2012 , 116 , 2075 - 2089 ) was investigated by its homologues 6CB and 8CB molecules. Note that, to construct the 5CB CG force field, we combined the structure-based and thermodynamic quantities-based methods and at the same time attempted to use several fragment molecular systems to derive the CG nonbonded interaction parameters. The resultant 5CB CG force field exhibits a good transferability to some extent. For example, not only the experimental densities, the local packing of atom groups, and the antiparallel arrangements of nearest neighboring molecules, but also the unique LC mesophases as well as the nematic-isotropic phase transition temperatures of 6CB and 8CB were reproduced. Meanwhile, the limitations of this 5CB CG force field were also observed, such as the phase transition from nematic to smectic was postponed to the lower temperature and the resulting smectic phase structure is single-layer-like instead of partially interdigitated bilayer-like as observed in underlying atomistic model. Apparently, more attention should be paid when applying a CG force field to the state point which is quite different from which the force field is explicitly parametrized for. The origin of the above limitations can be potentially traced back to the inherent simplifications and some approximations often adopted in the creation process of CG force field, for example, choosing symmetric CG potentials which do not explicitly include electrostatic interactions and are parametrized by reproducing the target properties of the specific nematic 5CB phase at 300 K and 1 atm, as well as using soft nonbonded potential and excluding torsion barriers. Moreover, although by construction this CG force field could inevitably incorporate both thermodynamic and local structural information on the nematic 5CB phase, the

  11. Monitoring suspended sediments and turbidity in Sahelian basins

    Science.gov (United States)

    Robert, Elodie; Grippa, Manuela; Kergoat, Laurent; Martinez, Jean-Michel; Pinet, Sylvain; Nogmana, Soumaguel

    2017-04-01

    Suspended matter can carry viruses and bacteria that are pathogenic to humans and can foster their development. Therefore, turbidity can be considered a vector of microbiological contaminants, which cause diarrheal diseases, and it can be used as a proxy for fecal bacteria. Few studies have focused on water turbidity in rural Africa, where many cases of intestinal parasitic infections are due to the consumption of unsafe water from ponds, reservoirs, lakes and rivers. Diarrheal diseases are indeed the second cause of infant mortality in sub-Saharan Africa. Furthermore, in this region, environment survey is minimal or inexistent. Monitoring water turbidity therefore represents a challenge for health improvement. Turbidity refers to the optical properties of water and it is well suited to monitoring by remote sensing. Because it varies in space and time and because the small water bodies (remote sensing and questions the methods developed for less turbid waters. In addition, high aerosol loadings (mineral dust and biomass burning) may be detrimental to turbidity retrieval in this region because of inaccurate atmospheric corrections. We propose a method to monitor water quality of Sahelian ponds, lakes and rivers using in-situ and remote sensing data, which is tested at different sites for which in-situ water turbidity and suspended sediments concentration (SSSC) measurements are acquired. Water sample are routinely collected at two sites within the AMMA-CATCH observatory part of the Réseau de Bassin Versants (RBV) French network: the Agoufou pond in northern Mali (starting September 2014), and the Niger River at Niamey in Niger (starting June 2015). These data are used to evaluate different indexes to derive water turbidity from the reflectance in the visible and infrared bands of high resolution optical sensors (LANDSAT, SENTINEL2). The temporal evolution of the turbidity of ponds, lakes and rivers is well captured at the seasonal and interannual scales with the

  12. Characteristics of sediment data and annual suspended-sediment loads and yields for selected lower Missouri River mainstem and tributary stations, 1976-2008

    Science.gov (United States)

    Heimann, David C.; Rasmussen, Patrick P.; Cline, Teri L.; Pigue, Lori M.; Wagner, Holly R.

    2010-01-01

    Suspended-sediment data from 18 selected surface-water monitoring stations in the lower Missouri River Basin downstream from Gavins Point Dam were used in the computation of annual suspended-sediment and suspended-sand loads for 1976 through 2008. Three methods of suspended-sediment load determination were utilized and these included the subdivision method, regression of instantaneous turbidity with suspended-sediment concentrations at selected stations, and regression techniques using the Load Estimator (LOADEST) software. Characteristics of the suspended-sediment and streamflow data collected at the 18 monitoring stations and the tabulated annual suspended-sediment and suspended-sand loads and yields are presented.

  13. UV durable colour pigment doped SmA liquid crystal composites for outdoor trans-reflective bi-stable displays

    Science.gov (United States)

    Xu, H.; Davey, A. B.; Crossland, W. A.; Chu, D. P.

    2012-10-01

    High brightness trans-reflective bi-stable displays based on smectic A (SmA) liquid crystals (LCs) can have nearly perfect transparency in the clear state and very high reflection in the scattered state. Because the LC material in use is stable under UV radiation, this kind of displays can stand for strong day-light and therefore be ideal for outdoor applications from e-books to public signage and advertisement. However, the colour application has been limited because the traditional colourants in use are conventional dyes which are lack of UV stability and that their colours are easily photo bleached. Here we present a colour SmA display demonstrator using pigments as colourant. Mixing pigments with SmA LCs and maintain the desirable optical switching performance is not straightforward. We show here how it can be done, including how to obtain fine sized pigment nano-particles, the effects of particle size and size distribution on the display performance. Our optimized pigments/SmA compositions can be driven by a low frequency waveform (~101Hz) to a scattered state to exhibit colour while by a high frequency waveform (~103Hz) to a cleared state showing no colour. Finally, we will present its excellent UV life-time (at least performances are still to be fully understood. We hope this work will not only demonstrate a new and practical approach for outdoor reflective colour displays but also provide a new material system for fundamental liquid crystal colloid research work.

  14. Storage filters upland suspended sediment signals delivered from watersheds

    Science.gov (United States)

    Pizzuto, James E.; Keeler, Jeremy; Skalak, Katherine; Karwan, Diana

    2017-01-01

    Climate change, tectonics, and humans create long- and short-term temporal variations in the supply of suspended sediment to rivers. These signals, generated in upland erosional areas, are filtered by alluvial storage before reaching the basin outlet. We quantified this filter using a random walk model driven by sediment budget data, a power-law distributed probability density function (PDF) to determine how long sediment remains stored, and a constant downstream drift velocity during transport of 157 km/yr. For 25 km of transport, few particles are stored, and the median travel time is 0.2 yr. For 1000 km of transport, nearly all particles are stored, and the median travel time is 2.5 m.y. Both travel-time distributions are power laws. The 1000 km travel-time distribution was then used to filter sinusoidal input signals with periods of 10 yr and 104 yr. The 10 yr signal is delayed by 12.5 times its input period, damped by a factor of 380, and is output as a power law. The 104 yr signal is delayed by 0.15 times its input period, damped by a factor of 3, and the output signal retains its sinusoidal input form (but with a power-law “tail”). Delivery time scales for these two signals are controlled by storage; in-channel transport time is insignificant, and low-frequency signals are transmitted with greater fidelity than high-frequency signals. These signal modifications are essential to consider when evaluating watershed restoration schemes designed to control sediment loading, and where source-area geomorphic processes are inferred from the geologic record.

  15. From nanostructured liquid crystals to electro-optic devices and lasers

    Science.gov (United States)

    Coles, Harry J.

    2004-05-01

    We have recently shown that bimesogenic liquid crystals exhibiting chiral nematic and smectic (SmA, SmA* or C*) phases have macroscopic electro-optic properties that make them very interesting for both display and non-display applications. Since materials have been synthesised where the optical effect observed could be due to scattering power, birefringence, dichroism, fluorescence and optical-nonlinearity (SHG and THG), and where the principle optical axis can be rotated in any direction through 90° in times of the order of microseconds at moderate fields, i.e., 1-10V per micron, then this suggests an exciting variety of new optoelectronic applications. In this paper we will describe nanoscopic design protocols, molecular templating effects and the molecular properties important for these systems. Specifically we will consider bimesogenic SmC* incorporating siloxane linking groups that exhibit either ferroelectric or anti-ferroelectric phases depending on the number of silicon atoms in the siloxane moiety using the same mesogens. The siloxane configuration leads to a molecular template effect observed on the macroscopic scale as synclinic or anticlinic phases. Unusually these materials have cone angles of up to and including 90¦ which makes them ideal for high contrast displays, phase elements, photonics transducers and lasers.

  16. Nondestructive optical testing of the materials surface structure based on liquid crystals

    Science.gov (United States)

    Tomilin, M. G.; Stafeev, S. K.

    2011-08-01

    Thin layers of nematic liquid crystals (NLCs) may be used as recording media for visualizing structural and microrelief defects, distribution of low power physical fields and modifications of the surface. NLCs are more sensitive in comparison with cholesteric and smectic LCs having super molecular structures. The detecting properties of NLCs are based on local layers deformation, induced by surface fields and observed in polarizing microscope. The structural surface defects or physical field's distribution are dramatically change the distribution of surface tension. Surface defects recording becomes possible if NLC deformed structure is illuminated in transparent or reflective modes and observed in optical polarizing microscope and appearing image is compared with background structure. In this case one observes not the real defect but the local deformation in NLCs. The theory was developed to find out the real size of defects. The resolution of NLC layer is more than 2000 lines/mm. The fields of NLC application are solid crystals symmetry, minerals, metals, semiconductors, polymers and glasses structure inhomogeneities and optical coatings defects detecting. The efficiency of NLC method in biophotonics is illustrated by objective detecting cancer tissues character and visualizing the interaction traces of grippe viruses with antibodies. NLCs may detect solvent components structure in tea, wine and perfume giving unique information of their structure. It presents diagnostic information alternative to dyes and fluorescence methods. For the first time the structures of some juices and beverages are visualized to illustrate the unique possibilities of NLCs.

  17. Label-free protein sensing by employing blue phase liquid crystal.

    Science.gov (United States)

    Lee, Mon-Juan; Chang, Chung-Huan; Lee, Wei

    2017-03-01

    Blue phases (BPs) are mesophases existing between the isotropic and chiral nematic phases of liquid crystals (LCs). In recent years, blue phase LCs (BPLCs) have been extensively studied in the field of LC science and display technology. However, the application of BPLCs in biosensing has not been explored. In this study, a BPLC-based biosensing technology was developed for the detection and quantitation of bovine serum albumin (BSA). The sensing platform was constructed by assembling an empty cell with two glass slides coated with homeotropic alignment layers and with immobilized BSA atop. The LC cells were heated to isotropic phase and then allowed to cool down to and maintained at distinct BP temperatures for spectral measurements and texture observations. At BSA concentrations below 10-6 g/ml, we observed that the Bragg reflection wavelength blue-shifted with increasing concentration of BSA, suggesting that the BP is a potentially sensitive medium in the detection and quantitation of biomolecules. By using the BPLC at 37 °C and the same polymorphic material in the smectic A phase at 20 °C, two linear correlations were established for logarithmic BSA concentrations ranging from 10-9 to 10-6 g/ml and from 10-6 to 10-3 g/ml. Our results demonstrate the potential of BPLCs in biosensing and quantitative analysis of biomolecules.

  18. Development of Polar Order by Liquid-Crystal Self-Assembly of Weakly Bent Molecules.

    Science.gov (United States)

    Alaasar, Mohamed; Prehm, Marko; Poppe, Silvio; Tschierske, Carsten

    2017-04-24

    Organic ferroelectrics are of growing importance for multifunctional materials. Here we provide an understanding of the distinct stages of the development of sterically induced polar order in liquid-crystalline (LC) soft matter. Three series of weakly bent molecules derived from 4-cyanoresorcinol as the bent core unit with laterally fluorinated azobenzene wings have been synthesized, and the effects of the position of fluorine substitution, alkyl-chain length, and temperature on the LC self-assembly and polar order were studied. In the LC phases a paraelectric-ferroelectric transition took place as the size of the polar domains gradually increased, thereby crossing a permittivity maximum, similar to inorganic solid-state ferroelectrics. An increase in polar coherence length simultaneously led to a transition from synpolar to antipolar domain correlation in the high-permittivity paraelectric range. Associated with the emergence of polar order was the development of a tilted organization of the molecules and a growing coherence of tilt. This led to a transition from non-tilted via tilt-randomized uniaxial to long-range-tilted biaxial smectic phases, and to surface-stabilized symmetry breaking with the formation of chiral conglomerates and field-induced tilt. Moreover, there is a remarkably strong effect of the position of fluorination; polar order is favored by peripheral core substitution and is suppressed by inside-directed fluorination. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Antiferroelectric and ferroelectric orderings in frustrated chiral tilted smectics and a continuous change from anticlinic SmCA* to synclinic SmC*

    Science.gov (United States)

    Sandhya, K. L.; Chandani-Perera, A. D. L.; Fukuda, Atsuo; Vij, J. K.; Ishikawa, Ken

    2010-06-01

    In a frustrated binary-mixture system of ferroelectric and antiferroelectric liquid crystals, where the border line between SmCA* and SmC* in the temperature-concentration phase diagram runs almost parallel to the ordinate temperature axis, we have found a continuous change between them close to the critical concentration. The continuity has been confirmed as an intrinsic property in the bulk by observing almost perfect bell-shaped Bragg reflection bands due to the helicoidal director structure. The temperature variation of peak wavelength of the half-pitch band and, in particular, the characteristic disappearance of the full-pitch band apparently within the SmC* temperature region have been simulated with a change in the ratio of ferroelectric and antiferroelectric orderings. The observed continuous change has been described by the entropy effect in the 1D Ising model with the synclinic and anticlinic orderings as spins.

  20. Ferroelektrische Cholesterin-Derivate

    Science.gov (United States)

    Vill, V.; Thiem, J.

    1990-10-01

    The feature of liquid crystalline phases of p-alkoxybenzoyloxycholesterins was elucidated. In addition to blue, cholesteric and smectic A phases also monotropic, ferroelectric smectic C phases were detected. p-Alkoxybenzoic anhydrides obtained as side products in esterification reactions show highly ordered smectic phases which resemble those of the isosteric propanediones.

  1. Particle size distribution of suspended solids in the Chesapeake Bay entrance and adjacent shelf waters

    Science.gov (United States)

    Byrnes, M. R.; Oertel, G. F.

    1981-01-01

    Characteristics of suspended solids, including total suspended matter, total suspended inorganics, total suspended organics, particle size distribution, and the presence of the ten most prominent particle types were determined. Four research vessels simultaneously collected samples along four transects. Samples were collected within a 2-hour period that coincided with the maximum ebb penetration of Chesapeake Bay outwelling. The distribution of primary and secondary particle size modes indicate the presence of a surface or near-surface plume, possibly associated with three sources: (1) runoff, (2) resuspension of material within the Bay, and/or (3) resuspension of material in the area of shoals at the Bay mouth. Additional supportive evidence for this conclusion is illustrated with ocean color scanner data.

  2. Residual fluxes of water, salt and suspended sediment in the Beypore Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; Revichandran, C.; Sankaranarayanan, V.N.; Josanto, V.

    The monthly trends of the residual fluxes of salt and water and the transportation of suspended sediments in the Beypore estuarine system, Kerala, India were examined. At the river mouth the water flux was directed seaward during the postmonsoon...

  3. Suspended sediment fluxes in a tropical estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

    Annual transport processes of suspended sediments in Beypore estuary - a tropical estuary along the south west coast of India - were investigated based on time series measurements within the system. It's observed that the sediment transport...

  4. Chlorophyll 'a' particulate organic carbon and suspended load from the mangrove areas of Cochin backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Sheeba, P.; Devi, K.S.; Balasubramanian, T.; Sankaranarayanan, V.N.

    Chlorophyll 'a' Particulate Organic Carbon and suspended load were estimated for one year from two distinct mangrove areas of Cochin backwaters, viz. Puthuvypeen and Nettoor. Environmental parameters like tau degrees C, S ppt and pH were also...

  5. Evaluation of Spinacia oleracea L. leaves mucilage as an innovative suspending agent.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Pany, Dipti Ranjan; Mohanty, Biswaranjan

    2010-07-01

    The present study was undertaken to evaluate the mucilage isolated from Spinacia oleracea L. leaves, commonly named spinach (family: Amaranthaceae) as an innovative suspending agent. Zinc oxide suspensions (20% w/v) were prepared using the mucilage of S. oleracea L. leaves as a suspending agent, and it was evaluated for its stability by using parameters like, sedimentation profile, degree of flocculation, and redispersibility. The effect of the tested mucilage on the suspension was compared with various commonly used suspending agents, such as, tragacanth, bentonite, and sodium carboxymethyl cellulose (NaCMC) at concentrations of 0.5, 1.0, and 2.0% w/v. The results obtained indicated that the mucilage of S. oleracea L. leaves could be used as a suspending agent, and the performance was found to be superior to both tragacanth and bentonite.

  6. Evaluation of Spinacia oleracea L. leaves mucilage as an innovative suspending agent

    Directory of Open Access Journals (Sweden)

    Amit Kumar Nayak

    2010-01-01

    Full Text Available The present study was undertaken to evaluate the mucilage isolated from Spinacia oleracea L. leaves, commonly named spinach (family: Amaranthaceae as an innovative suspending agent. Zinc oxide suspensions (20% w/v were prepared using the mucilage of S. oleracea L. leaves as a suspending agent, and it was evaluated for its stability by using parameters like, sedimentation profile, degree of flocculation, and redispersibility. The effect of the tested mucilage on the suspension was compared with various commonly used suspending agents, such as, tragacanth, bentonite, and sodium carboxymethyl cellulose (NaCMC at concentrations of 0.5, 1.0, and 2.0% w/v. The results obtained indicated that the mucilage of S. oleracea L. leaves could be used as a suspending agent, and the performance was found to be superior to both tragacanth and bentonite.

  7. 76 FR 80982 - International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities

    Science.gov (United States)

    2011-12-27

    ...-0292] International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities I International Cyclotron, Inc. (International Cyclotron; Licensee) is the holder of Byproduct Materials License... International Cyclotron submitted its NRC license application related to the cyclotron, it requested...

  8. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

    NARCIS (Netherlands)

    Overeem, I.; Hudson, Brian D; Syvitski, James P. M.; Mikkelsen, Andreas B.; Hasholt, B.; van den Broeke, M. R.; Noel, B. P. Y.; Morlighem, M.

    2017-01-01

    Limited measurements along Greenland’s remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate

  9. Seasonal variations of total suspended matter (TSM) in the Gulf of Khambhat, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Misra, A.; ManiMurali, R.; Sukumaran, S.; Vethamony, P.

    Total Suspended Matter (TSM)is an important parameter for determining the water quality in coastal regions as it is responsible for the reduction in the light available to the aquatic vegetation which subsequently alters the health and quality...

  10. Natural isotopic composition of nitrogen in suspended particulate matter in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, S.; Ramesh, R.; Bhosle, N.B.; Sardessai, S.; Sheshshayee, M.S.

    The first measurements of nitrogen isotopic composition (delta sup(15) N) in suspended particulate matter (SPM) of the surface Bay of Bengal (BOB) at 24 different locations during pre- (April-May 2003) and post- (September-October 2002) monsoon...

  11. Experimental realization of suspended atomic chains composed of different atomic species

    Energy Technology Data Exchange (ETDEWEB)

    Bettini, Jefferson; Ugarte, Daniel [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil); Sato, Fernando; Galvao, Douglas Soares [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin; Coura, Pablo Zimmerman; Dantas, Socrates de Oliveira [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Inst. de Ciencias Exatas. Dept. de Fisica

    2006-07-01

    We report high resolution transmission electron microscopy (HRTEM) and molecular dynamics results of the first experimental test of suspended atomic chains composed of different atomic species formed from spontaneous stretching of metallic nanowires. (author)

  12. Continuous-flow centrifugation to collect suspended sediment for chemical analysis

    Science.gov (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

    2016-12-22

    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  13. A study of metal ion adsorption at low suspended-solid concentrations

    Science.gov (United States)

    Chang, Cecily C.Y.; Davis, J.A.; Kuwabara, J.S.

    1987-01-01

    A procedure for conducting adsorption studies at low suspended solid concentrations in natural waters (NaCl) concentration (0??1-0??002 m) and particle concentration (2-50 mg l-1). The lack of success of the Davis Leckie site bonding model in describing Zn(II) adsorption emphasizes the need for further studies of adsorption at low suspended-solid concentrations. ?? 1987.

  14. Wavelength-Tunable IR Detector based on Suspended Bilayer Graphene Micro Ribbons

    Science.gov (United States)

    2013-11-05

    high purity copper foil using a low pressure CVD furnace at 1000 oC in a hydrogen, argon and methane environment. Raman spectrum of the graphene ...characterized in Year One a device with suspended graphene microribbons, and found that fully suspended CVD -grown graphene devices are dominated by the...photoelectric effect, which is promising towards CVD -grown graphene photodetectors approaching THz cut-off frequencies. chemical vapor deposition, strain

  15. Measurement of Suspended Sediment Transport Processes off the Holderness Coast - Southern North Sea, England

    OpenAIRE

    Blewett, Joanna Catherine

    1998-01-01

    A field campaign was set up as part of the LOIS-RACS coastal program (1994-1996), to identify the near-bed physical processes responsible for suspended sediment movement in shallow water (10-20m depth) off the Holdemess coast, NE England. A new benthic tripod system Boundary Layer Intelligent Sensor System (BLISS) has been developed and deployed along a transect at three sites, normal to the coastline at Tunstall. Measurements of current velocity, suspended sediment concentrati...

  16. Thermal instability of Walters B' viscoelastic fluid permeated with suspended particles in hydromagnetics in porous medium

    Directory of Open Access Journals (Sweden)

    Kumar Pardeep

    2004-01-01

    Full Text Available The effect of suspended particles on the thermal instability of Walters B' viscoelastic fluid in hydromantic in porous medium is considered. For stationary convection, Walters B' viscoelastic fluid behaves like a Newtonian fluid. The medium permeability and suspended particles has ten the onset of convection whereas the magnetic field postpones the onset of convection, for the case of stationary convection. The magnetic field and viscoelasticity intro duce oscillatory modes in the system which was non-existent in their absence.

  17. Characterization of surface liquid segregation in SSM-HPDC aluminium alloys 7075, 2024, 6082 and A201

    CSIR Research Space (South Africa)

    Moller, H

    2010-09-01

    Full Text Available Semi-solid metal (SSM) processing is a unique manufacturing method to produce near-net shape products for various industrial applications. The nature of the SSM slurry (with solid spherical grains suspended in a liquid), makes it susceptible...

  18. A Generalized Mathematical Model for the Fracture Problem of the Suspended Highway

    Directory of Open Access Journals (Sweden)

    Zhao Ying

    2017-01-01

    Full Text Available In order to answer dangling fracture problems of highway, the suspended pavement equivalent for non - suspended pavement, through the special boundary conditions has been suspended highway stress field of expression, in accordance with the 3D fracture model of crack formation, and establish a vacant, a general mathematics model for fracture problems of highway and analysis in highway suspended segment weight and vehicle load limit of highway capacity of Pu For overturning road inPu is less than the force of carrying more than compared to the work and fruit Bridge Hydropower Station Road engineering examples to verify suspended highway should force field expressions for the correctness and applicability. The results show that: when the hanging ratio R 0. 243177 limits of Pu design axle load 100kN. When the vertical crack in the vacant in the direction of length greater than 0. 1, the ultimate bearing capacity is less than the design axle load 100kN; when the hanging ratio R is less than 0. 5, the road to local fracture, the ultimate bearing capacity of suspended stress field expressions in solution; when the hanging ratio is greater than or equal to 0. 5, the road does not reach the limit bearing capacity of the whole body; torque shear surface of the effect is far less than the bending moments on shear planes.

  19. Spatial and temporal variability of suspended-sediment concentrations in a shallow estuarine environment

    Directory of Open Access Journals (Sweden)

    Catherine A. Ruhl

    2004-05-01

    Full Text Available Shallow subembayments respond differently than deep channels to physical forces acting in estuaries. The U.S. Geological Survey measured suspended-sediment concentrations at five locations in Honker Bay, a shallow subembayment of San Francisco Bay, and the adjacent channel to investigate the spatial and temporal differences between deep and shallow estuarine environments. During the first freshwater pulse of the wet season, the channel tended to transport suspended sediments through the system, whereas the shallow area acted as off-channel storage where deposition would likely occur. Following the freshwater pulse, suspended-sediment concentrations were greater in Honker Bay than in the adjacent deep channel, due to the larger supply of erodible sediment on the bed. However, the tidal variability of suspended-sediment concentrations in both Honker Bay and in the adjacent channel was greater after the freshwater pulse than before. During wind events, suspended-sediment concentrations in the channel were not affected; however, wind played a crucial role in the resuspension of sediments in the shallows. Despite wind-wave sediment resuspension in Honker Bay, tidally averaged suspended-sediment flux was controlled by the flood-dominated currents.

  20. Liquid Droplet Dynamics in Gravity Compensating High Magnetic Field

    Science.gov (United States)

    Bojarevics, V.; Easter, S.; Pericleous, K.

    2012-01-01

    Numerical models are used to investigate behavior of liquid droplets suspended in high DC magnetic fields of various configurations providing microgravity-like conditions. Using a DC field it is possible to create conditions with laminar viscosity and heat transfer to measure viscosity, surface tension, electrical and thermal conductivities, and heat capacity of a liquid sample. The oscillations in a high DC magnetic field are quite different for an electrically conducting droplet, like liquid silicon or metal. The droplet behavior in a high magnetic field is the subject of investigation in this paper. At the high values of magnetic field some oscillation modes are damped quickly, while others are modified with a considerable shift of the oscillating droplet frequencies and the damping constants from the non-magnetic case.

  1. A Nanoaquarium for in situ Electron Microscopy in Liquid Media

    CERN Document Server

    Grogan, Joseph M

    2010-01-01

    The understanding of many nanoscale processes occurring in liquids such as colloidal crystal formation, aggregation, nanowire growth, electrochemical deposition, and biological interactions would benefit greatly from real-time, in situ imaging with the nanoscale resolution of transmission electron microscopes (TEMs) and scanning transmission electron microscopes (STEMs). However, these imaging tools cannot readily be used to observe processes occurring in liquid media without addressing two experimental hurdles: sample thickness and sample evaporation in the high vacuum microscope chamber. To address these challenges, we have developed a nano-Hele-Shaw cell, dubbed the nanoaquarium. The device consists of a hermetically-sealed, 100 nm tall, liquid-filled chamber sandwiched between two freestanding, 50 nm thick, silicon nitride membranes. Embedded electrodes are integrated into the device. This fluid dynamics video features particle motion and aggregation during in situ STEM of nanoparticles suspended in liqui...

  2. SEASONAL DISTRIBUTION OF TOTAL SUSPENDED MATTER IN SUMBAWA SEA

    Directory of Open Access Journals (Sweden)

    IGAG SWANDANA

    2015-05-01

    Full Text Available Distribusi Musiman Total Suspended Matter (TSM di Laut Surnbawa (117" - us· Edan s· - 9· S telah dilakukan. Data TSM tersebut diperoleh dari 75 stasiun pengukuran pada bulan September 2005 dan 98 stasiun pengukuran pada bulan November 2005 dan April 2006. Besaran sebaran TSM diperoleh dari hasil perhitungan besaran turbidity yang diperoleh dari pengukuran dengan menggunakan alat CTD ( Conductivity, Temperature and Depth Sensors. Besaran TSM yang diperoleh dari besaran turbidity menggunakan rurnus TSM = 0,65 Tur+ 1,17 (r = 0,85 (Hoshika dan Tanimoto, 1997.  Distribusi sebaran TSM pada saat musim hujan menunjukkan bahwa besarnya bervariasi dari L060 sam­pai 2.951 mg/1 dengan rata-rata sebesar 1.152 mg/1 (n=98, di lain pihak pada saat musim kemarau distribusi sebaran TSM menunjukkan bahwa besarnya bervariasi dari 1.060 sampai 2.899 mg/1 dengan rata-rata sebesar 1.111 mg/I (n=75. Distribusi sebaran TSM secara vertical dari permukaan laut sampai dengan kedalaman 20 meter menunjukkan bahwa terjadi perbedaan yang signifikan antara musim kemarau dan musim hujan. Pada saat musim kemarau distribusi sebaran TSM pada permukaan laut sampai dengan kedalaman 20 meter mem­punyai variasi yang kecil (dari 1.079 sampai 1.599 mg/1; Pada saat musim hujan distribusi sebaran TSM pada permukaan laut sampai dengan kedalaman 20 meter mempunyai variasi yang sangat besar (dari 1.079 sampai 2.698 mg/1. Distribusi sebaran TSM dari kedalaman 20 meter sampai dengan 100 meter menunjukkan pola yang sama antara musim kemarau dan musim hujan.  Distribusi sebaran TSM pada permukaan laut (dekat sungai/muara menunjukkan bahwa terjadi perbedaan sebaran antara musim kemarau dan musim hujan. Demikian juga dengan distribusi sebaran TSM yang diper­oleh dari data satelit menunjukkan bahwa terjadi perbedaan sebaran antara musim kemarau dan musim hujan. Perbandingan antara data in situ dengan data satelit menunjukkan bahwa koefisen korelasinya sebesar -0-753 untuk periode penelitian

  3. Controls on suspended aggregate size in partially mixed estuaries

    Science.gov (United States)

    Fugate, David C.; Friedrichs, Carl T.

    2003-10-01

    Knowledge of aggregate size in estuaries is important to determining the fate and transport of suspended sediment and particle adherent contaminants. We have used a suite of in situ instruments to determine the controls of aggregate size distributions in three muddy, partially mixed estuaries in the mid-Atlantic USA. A novel method is presented to estimate turbulent kinetic energy (TKE) production and the resulting Kolmogorov microscale ( λK) using a profiling acoustic Doppler velocimeter that has been contaminated by boat motion. The physical processes that control particle size distribution differ in the three estuaries due to the different hydrodynamics and benthic characteristics. Controls within each estuary also vary with different depth regimes. Surface particle size dynamics in all the studied estuaries are affected by irregular advection events. In the hydrodynamically energetic York River, mid-depth regions are controlled tidally by the combined processes of small λK decreasing particle size at high TKE and differential settling increasing particle size during lower TKE, more stratified conditions. Mid-depth regions in the lower energy Elizabeth River are controlled by irregular resuspension and trapping at the pycnocline of large low density particles. Bottom regions in all estuaries are most strongly influenced by resuspension, tidally in the energetic estuaries and irregularly in the low energy estuary. Near-bed particle size distributions are controlled by both λK and the distribution of particles in the bed in the higher energy estuaries. Just above the bed, large porous particles survive resuspension in the lower energy Elizabeth River, particles become smaller with decreased λK in the more energetic York River, and biological aggregation causes large dense particles to resist turbulent breakup in the Chesapeake Bay, which has a more active benthic community. The net result just above the bed is that particle size and settling velocity are

  4. Liquid-based stationary phase for deterministic lateral displacement separation in microfluidics.

    Science.gov (United States)

    Du, Siqi; Shojaei-Zadeh, Shahab; Drazer, German

    2017-10-25

    Deterministic lateral displacement (DLD) is a promising separation scheme in microfluidic systems. In traditional DLD, a periodic array of solid posts induces the separative migration of suspended particles moving through the system. Here, we present a radical departure from traditional DLD systems and use an array of anchored liquid-bridges as the stationary phase in the DLD device. The liquid-bridges are created between two parallel plates and anchored to the bottom one by cylindrical wells. We show that the non-linear particle dynamics observed in traditional DLD systems is also present in the anchored-liquid case, enabling analogous size-based separation of suspended particles. The use of liquid-bridges as the stationary phase presents additional possibilities in separation technologies, potentially eliminating or significantly reducing clogging, enabling renewable and/or reconfigurable systems, allowing a different set of fabrication methods and providing alternative ways to separate particles based on their interaction with liquid-liquid interfaces. Some of these advantages could also extend to filtration methods based on similar liquid-based stationary phases.

  5. PREFACE: The Eighth Liquid Matter Conference The Eighth Liquid Matter Conference

    Science.gov (United States)

    Dellago, Christoph; Kahl, Gerhard; Likos, Christos N.

    2012-07-01

    Daoulas, Victor Rühle and Kurt Kremer Smectic shellsTeresa Lopez-Leon, Alberto Fernandez-Nieves, Maurizio Nobili and Christophe Blanc Intrinsic profiles and the structure of liquid surfacesP Tarazona, E Chacón and F Bresme Competing ordered structures formed by particles with a regular tetrahedral patch decorationGünther Doppelbauer, Eva G Noya, Emanuela Bianchi and Gerhard Kahl Heterogeneous crystallization in colloids and complex plasmas: the role of binary mobilitiesH Löwen, E Allahyarov, A Ivlev and G E Morfill Isotope effects in water as investigated by neutron diffraction and path integral molecular dynamicsAnita Zeidler, Philip S Salmon, Henry E Fischer, Jörg C Neuefeind, J Mike Simonson and Thomas E Markland Confined cubic blue phases under shearO Henrich, K Stratford, D Marenduzzo, P V Coveney and M E Cates Depletion-induced biaxial nematic states of boardlike particlesS Belli, M Dijkstra and R van Roij Active Brownian motion tunable by lightIvo Buttinoni, Giovanni Volpe, Felix Kümmel, Giorgio Volpe and Clemens Bechinger Structure and stability of charged clustersMark A Miller, David A Bonhommeau, Christopher J Heard, Yuyoung Shin, Riccardo Spezia and Marie-Pierre Gaigeot Non-equilibrium relaxation and tumbling times of polymers in semidilute solutionChien-Cheng Huang, Gerhard Gompper and Roland G Winkler Thermophoresis of colloids by mesoscale simulationsDaniel Lüsebrink, Mingcheng Yang and Marisol Ripoll Computing the local pressure in molecular dynamics simulationsThomas W Lion and Rosalind J Allen Gradient-driven fluctuations in microgravityA Vailati, R Cerbino, S Mazzoni, M Giglio, C J Takacs and D S Cannell

  6. Headspace single drop microextraction versus dispersive liquid-liquid microextraction using magnetic ionic liquid extraction solvents.

    Science.gov (United States)

    An, Jiwoo; Rahn, Kira L; Anderson, Jared L

    2017-05-15

    A headspace single drop microextraction (HS-SDME) method and a dispersive liquid-liquid microextraction (DLLME) method were developed using two tetrachloromanganate ([MnCl42-])-based magnetic ionic liquids (MIL) as extraction solvents for the determination of twelve aromatic compounds, including four polyaromatic hydrocarbons, by reversed phase high-performance liquid chromatography (HPLC). The analytical performance of the developed HS-SDME method was compared to the DLLME approach employing the same MILs. In the HS-SDME approach, the magnetic field generated by the magnet was exploited to suspend the MIL solvent from the tip of a rod magnet. The utilization of MILs in HS-SDME resulted in a highly stable microdroplet under elevated temperatures and long extraction times, overcoming a common challenge encountered in traditional SDME approaches of droplet instability. The low UV absorbance of the [MnCl42-]-based MILs permitted direct analysis of the analyte enriched extraction solvent by HPLC. In HS-SDME, the effects of ionic strength of the sample solution, temperature of the extraction system, extraction time, stir rate, and headspace volume on extraction efficiencies were examined. Coefficients of determination (R2) ranged from 0.994 to 0.999 and limits of detection (LODs) varied from 0.04 to 1.0μgL-1 with relative recoveries from lake water ranging from 70.2% to 109.6%. For the DLLME method, parameters including disperser solvent type and volume, ionic strength of the sample solution, mass of extraction solvent, and extraction time were studied and optimized. Coefficients of determination for the DLLME method varied from 0.997 to 0.999 with LODs ranging from 0.05 to 1.0μgL-1. Relative recoveries from lake water samples ranged from 68.7% to 104.5%. Overall, the DLLME approach permitted faster extraction times and higher enrichment factors for analytes with low vapor pressure whereas the HS-SDME approach exhibited better extraction efficiencies for analytes with

  7. Chiral smectic transition phases appearing near the electric-field-induced phase transition observed by resonant microbeam x-ray scattering.

    Science.gov (United States)

    Iida, Atsuo; Nishiyama, Isa; Takanishi, Yoichi

    2014-03-01

    The electric-field-induced phase transition of a chiral liquid crystal containing Br revealed a transition phase between the three-layer periodicity ferrielectric phase and the synclinic ferroelectric phase in the electric field versus temperature phase diagram. Resonant x-ray scattering from the transition phase showed a diffuse streak or spotty weak reflections, which were composed of strong m/3-order (where m = 1 and 2) reflections and other weak peaks. The spotty reflections were found to be related to a 12-layer periodicity phase with a weak contribution from the 15-layer periodicity. An x-ray intensity analysis based on the Ising model suggested that the 12-layer periodicity phase was composed of two three-layer ferrielectric blocks and six synclinic layers. This model indicated that, in the transition phase, the three-layer ferrielectric molecular configuration gradually changed to the synclinic configuration. The diffuse streak appearing around m/3-order reflections near the field-induced transition from the four-layer periodicity phase to the synclinic ferroelectric phase is also discussed.

  8. Suspended-sediment concentrations, yields, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    Science.gov (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2015-01-01

    Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, as well as transporting harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentration (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples were collected from 14 sites from 2007 through 2011. Analyses of these data indicated that the Zumbro River at Kellogg in southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. The single highest SSC of 1,250 mg/L was measured at the Zumbro River during the 2011 spring runoff. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis-St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been known to underrepresent the amount of suspended sediment. For this study, comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. Regression analysis indicated that 7 out of 14 sites had poor or no relation between SSC and streamflow. Only two sites, the Knife River and the Wild Rice River at Twin Valley, had strong correlations between SSC and streamflow, with coefficient of determination (R2) values of 0.82 and 0.80, respectively. In contrast, turbidity had moderate to strong

  9. Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    Science.gov (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2014-01-01

    Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

  10. Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Madder, Ryan D., E-mail: ryan.madder@spectrumhealth.org; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

    2017-04-15

    Background: Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Methods: Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Results: Among 336 cases (86.6% manual, 13.4% robotic) performed over 30 weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, p < 0.001; head: 0.5 [1.9] μSv vs 14.9 [51.5] μSv, p < 0.001). Chest-level radiation exposure during robotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (p < 0.001) or suspended lead (p = 0.046). In robotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (p < 0.001) and 80.0% less than manual PCI performed with suspended lead (p < 0.001). Conclusions: Utilization of suspended lead and robotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. - Highlights: • Use of suspended lead during manual PCI reduced cranial radiation among operators by 97%. • Robotic PCI reduced cranial radiation among operators by 99%. • Suspended lead and robotics together achieved the lowest levels of radiation exposure.

  11. A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

    Science.gov (United States)

    Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

    2017-09-01

    Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

  12. Long-term continuous acoustical suspended-sediment measurements in rivers - Theory, application, bias, and error

    Science.gov (United States)

    Topping, David J.; Wright, Scott A.

    2016-05-04

    It is commonly recognized that suspended-sediment concentrations in rivers can change rapidly in time and independently of water discharge during important sediment‑transporting events (for example, during floods); thus, suspended-sediment measurements at closely spaced time intervals are necessary to characterize suspended‑sediment loads. Because the manual collection of sufficient numbers of suspended-sediment samples required to characterize this variability is often time and cost prohibitive, several “surrogate” techniques have been developed for in situ measurements of properties related to suspended-sediment characteristics (for example, turbidity, laser-diffraction, acoustics). Herein, we present a new physically based method for the simultaneous measurement of suspended-silt-and-clay concentration, suspended-sand concentration, and suspended‑sand median grain size in rivers, using multi‑frequency arrays of single-frequency side‑looking acoustic-Doppler profilers. The method is strongly grounded in the extensive scientific literature on the incoherent scattering of sound by random suspensions of small particles. In particular, the method takes advantage of theory that relates acoustic frequency, acoustic attenuation, acoustic backscatter, suspended-sediment concentration, and suspended-sediment grain-size distribution. We develop the theory and methods, and demonstrate the application of the method at six study sites on the Colorado River and Rio Grande, where large numbers of suspended-sediment samples have been collected concurrently with acoustic attenuation and backscatter measurements over many years. The method produces acoustical measurements of suspended-silt-and-clay and suspended-sand concentration (in units of mg/L), and acoustical measurements of suspended-sand median grain size (in units of mm) that are generally in good to excellent agreement with concurrent physical measurements of these quantities in the river cross sections at

  13. Lipid decorated liquid crystal pressure sensors

    Science.gov (United States)

    Lopatkina, Tetiana; Popov, Piotr; Honaker, Lawrence; Jakli, Antal; Mann, Elizabeth; Mann's Group Collaboration; Jakli's Group Collaboration

    Surfactants usually promote the alignment of liquid crystal (LC) director parallel to the surfactant chains, and thus on average normal to the substrate (homeotropic), whereas water promotes tangential (planar) alignment. A water-LC interface is therefore very sensitive to the presence of surfactants, such as lipids: this is the principle of LC-based chemical and biological sensing introduced by Abbott et al.Using a modified configuration, we found that at higher than 10 micro molar lipid concentration, the uniformly dark texture seen for homeotropic alignment between left-, and right-handed circular polarizers becomes unstable and slowly brightens again. This texture shows extreme sensitivity to external air pressure variations offering its use for sensitive pressure sensors. Our analysis indicates an osmotic pressure induced bending of the suspended films explaining both the birefringence and pressure sensitivity. In the talk we will discuss the experimental details of these effects. This work was financially supported by NSF DMR No. DMR-0907055.

  14. Recent Trends in Suspended Sediment Load & Water Quality in the Upper Chesapeake Bay

    Science.gov (United States)

    Freeman, L. A.; Ackleson, S. G.

    2016-02-01

    The Chesapeake Bay spans several major cities on the US east coast and drains a large watershed (164,200 km2) to the Atlantic Ocean. Upstream deforestation and agriculture have led to a major decline in water quality (increased sediment and nutrient load) of the Bay over the past century. Sediment flux into the Chesapeake Bay is a natural process, but has become an environmental concern as land use changes have exacerbated natural suspended sediment loads and saturated the capacity of the estuary to filter and remove sediments. In situ measurements of suspended sediments and surface reflectance from the Potomac, Patapsco, and Severn River were used to develop algorithms that convert surface reflectance from Landsat (1-3, 4-5, 7, 8) imagery to suspended sediment concentration for the entire Chesapeake Bay. A unique time series of suspended sediment load in the Chesapeake Bay was compiled from Landsat imagery dating from 1977-2015. Particular focus is given to the upper Chesapeake Bay near Washington, DC and Baltimore, MD to understand urban effects. In particular, the Potomac, Patapsco, and Severn River are examined from both remote sensing and in situ measurements. Landsat imagery combined with in situ monitoring provides environmental scientists and resource managers with detailed trends in sediment distribution and concentration, a key measure of water quality. Trends of suspended sediment load in several rivers and the upper Chesapeake Bay will be presented, along with a discussion of suspended sediment algorithms for Landsat imagery. Advantages of Landsat 8 (improved signal-to-noise performance and more bands) versus previous sensors will be examined for suspended sediment applications.

  15. Suspended and Bedload Sand dynamics in the Mekong River Channel and Export to the Coastal Ocean

    Science.gov (United States)

    Stephens, J. D.; Di Leonardo, D. R.; Weathers, H. D., III; Allison, M. A.

    2016-02-01

    Two field campaigns were conducted in the tidal and estuarine reach of the Song Hau distributary of the Mekong River to examine the dynamics of sand transport and export to the coastal ocean. This study examines variation in suspended sand concentration and net transport with respect to changes in discharge between the October 2014 high discharge and March 2015 low discharge studies, and over semi-diurnal and spring-neap tidal cycles between Can Tho and the Tran De and Dinh An distributary channels in the Mekong Delta. Suspended sand concentrations were measured using a P-61 isokinetic suspended sediment sampler and a Sequoia Scientific LISST-100X used in vertical profiling mode. Stationary ADCP data are used to examine bed stress at cast sites. Bed load transport rates were calculated using a repeat multibeam transect methodology and dune translation rates with flow. Preliminary results indicate that suspended sand concentration increases towards the bed and is positively correlated with increasing shear stress controlled by river discharge and tides. However, sites with non-sandy bottoms, as indicated by multibeam bathymetry, have low suspended sand concentrations, suggesting a close linkage with a bed sand source. Bed load transport rates vary cross-sectionally with shear stress and are linked to dune size. Most bed load transport is taking place in or near the thalweg. The reduction in ebb flows at low discharge and the mantling of sand fields by salinity driven mud deposition, is suspected to control the low suspended sand concentrations observed in March. Results to date suggest that net sand export (suspended plus bed load) to the ocean occurs predominantly during the high discharge monsoon season.

  16. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger

    2017-12-01

    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  17. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Helena A.; Maher, William A., E-mail: bill.maher@canberra.edu.au; Taylor, Anne M.; Krikowa, Frank

    2015-03-15

    Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.

  18. SEBARAN TOTAL SUSPENDED SOLID (TSS PADA PROFIL VERTIKAL DI PERAIRAN SELAT MADURA KABUPATEN BANGKALAN

    Directory of Open Access Journals (Sweden)

    Aries Dwi Siswanto

    2015-04-01

    Full Text Available Sebaran sedimen tersuspensi (Total Suspended Solid (TSS dapat dipelajari secara horizontal maupun vertikal. Akumulasi sedimen tersuspensi (TSS secara horizontal sangat dipengaruhi oleh arus permukaan maupun gelombang yang dibangkitkan oleh angin. Keterdapatan TSS ini diduga berpengaruh terhadap sebarannya pada profil vertical. Kedua kondisi sebaran sedimen tersuspensi (TSS berpengaruh terhadap optimalisasi penetrasi cahaya matahari di perairan. Sedimen tersuspensi (TSS menjadi salah satu factor fisika yang penting sebagai indicator kondisi perairan. Penelitian ini bertujuan untuk mengetahui sebaran Total Suspended Solid (TSS di perairan Kabupaten Bangkalan. Materi utama yang digunakan dalam penelitian ini adalah contoh air dan data parameter lingkungan (pasang surut dan kecerahan yang diambil pada 7 stasiun pada bulan Agustus-September 2013 di Perairan Selat Madura, Kabupaten Bangkalan. Metode gravimetric (SNI-06-6989.3-2004 digunakan untuk analisa Total Suspended Solid (TSS. Data parameter lingkungan dianalisa secara deskriptif. Analisa TSS menunjukkan nilai yang berbeda pada beberapa stasiun penelitian untuk setiap minggunya. Konsentrasi TSS terendah sebesar 35 mg/L (Stasiun 3, profil permukaan, minggu pertama dan tertinggi sebesar 620 mg/L (Stasiun 4, profil dasar, minggu pertama. Secara umum, konsentrasi TSS secara vertikal (dari permukaan-dasar cenderung semakin besar, diduga dipengaruhi oleh jenis substrat dan parameter arus yang berpeluang untuk menimbulkan pengadukan di profil dasar. Kondisi lingkungan (kecerahan dan arus menunjukkan bahwa daerah dengan konsentrasi TSS yang tinggi cenderung memilki nilai kecerahan yang rendah dengan kecepatan arus yang lebih besar.Kata Kunci: kecerahan, pola arus, Total Suspended Solid (TSS DISTRIBUTION OF TOTAL SUSPENDED SOLID (TSS IN THE VERTICAL PROFILE IN THE MADURA STRAIT WATERS BANGKALAN DISTRICTABSTRACTDistribution of suspended sediment (Total Suspended Solid (TSS can be studied through

  19. VAPOR SPACE AND LIQUID/AIR INTERFACECORROSION TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Zapp, P.; Hoffman, E.

    2009-11-09

    The phenomena of vapor space corrosion and liquid/air interface corrosion of carbon steel in simulated liquid waste environments have been investigated. Initial experiments have explored the hypothesis that vapor space corrosion may be accelerated by the formation of a corrosive electrolyte on the tank wall by a process of evaporation of relatively warmer waste and condensation of the vapor on the relatively cooler tank wall. Results from initial testing do not support the hypothesis of electrolyte transport by evaporation and condensation. The analysis of the condensate collected by a steel specimen suspended over a 40 C simulated waste solution showed no measurable concentrations of the constituents of the simulated solution and a decrease in pH from 14 in the simulant to 5.3 in the condensate. Liquid/air interface corrosion was studied as a galvanic corrosion system, where steel at the interface undergoes accelerated corrosion while steel in contact with bulk waste is protected. The zero-resistance-ammeter technique was used to measure the current flow between steel specimens immersed in solutions simulating (1) the high-pH bulk liquid waste and (2) the expected low-pH meniscus liquid at the liquid/air interface. Open-circuit potential measurements of the steel specimens were not significantly different in the two solutions, with the result that (1) no consistent galvanic current flow occurred and (2) both the meniscus specimen and bulk specimen were subject to pitting corrosion.

  20. Tellurite suspended nanowire surrounded with large holes for single-mode SC and THG generations

    Science.gov (United States)

    Liao, Meisong; Qin, Guanshi; Yan, Xin; Chaudhari, Chitrarekha; Suzuki, Takenobu; Ohishi, Yasutake

    2011-05-01

    For a suspended nanowire, the holes surrounding the core are expected to be as large as possible to propagate the light at wavelengths as long as possible. However, the fabrication of nanowire surrounded with large holes is still a challenge so far. In this paper, a method which involves pumping positive pressure of nitrogen gas in both the cane fabrication and fiber-drawing processes, is proposed. A suspended nanowire, with a core diameter of 480 nm and an unprecedented large diameter ratio of holey region to core (DRHC) of at least 62, is fabricated in the length of several hundred meters. Owing to the large holes, the confinement loss of the suspended nanowire is insignificant when the wavelength of light propagated in it is 1700 nm. Additionally, the tube-shaped glass cladding of the suspended nanowire shifts the singlemode cutoff wavelength to 810 nm, which is much shorter than the cutoff wavelength, 1070 nm, of a naked nanowire with the same diameter. A single-mode supercontinuum (SC) generation covering a wavelength range of 900-1600 nm is obtained under 1064 nm pump pulse with the peak power as low as 24 W. A single-mode third harmonic generation (THG) is observed by this nanowire under the pump of a 1557 nm femtosecond fiber laser. This work indicates that the suspended nanowire with large holes can provide high nonlinearity together with single-mode propagation, which leads to interesting applications in compact nonlinear devices.

  1. A Case Study of Dynamic Response Analysis and Safety Assessment for a Suspended Monorail System

    Directory of Open Access Journals (Sweden)

    Yulong Bao

    2016-11-01

    Full Text Available A suspended monorail transit system is a category of urban rail transit, which is effective in alleviating traffic pressure and injury prevention. Meanwhile, with the advantages of low cost and short construction time, suspended monorail transit systems show vast potential for future development. However, the suspended monorail has not been systematically studied in China, and there is a lack of relevant knowledge and analytical methods. To ensure the health and reliability of a suspended monorail transit system, the driving safety of vehicles and structure dynamic behaviors when vehicles are running on the bridge should be analyzed and evaluated. Based on the method of vehicle-bridge coupling vibration theory, the finite element method (FEM software ANSYS and multi-body dynamics software SIMPACK are adopted respectively to establish the finite element model for bridge and the multi-body vehicle. A co-simulation method is employed to investigate the vehicle-bridge coupling vibration for the transit system. The traffic operation factors, including train formation, track irregularity and tire stiffness, are incorporated into the models separately to analyze the bridge and vehicle responses. The results show that the coupling of dynamic effects of the suspended monorail system between vehicle and bridge are significant in the case studied, and it is strongly suggested to take necessary measures for vibration suppression. The simulation of track irregularity is a critical factor for its vibration safety, and the track irregularity of A-level road roughness negatively influences the system vibration safety.

  2. A Case Study of Dynamic Response Analysis and Safety Assessment for a Suspended Monorail System.

    Science.gov (United States)

    Bao, Yulong; Li, Yongle; Ding, Jiajie

    2016-11-10

    A suspended monorail transit system is a category of urban rail transit, which is effective in alleviating traffic pressure and injury prevention. Meanwhile, with the advantages of low cost and short construction time, suspended monorail transit systems show vast potential for future development. However, the suspended monorail has not been systematically studied in China, and there is a lack of relevant knowledge and analytical methods. To ensure the health and reliability of a suspended monorail transit system, the driving safety of vehicles and structure dynamic behaviors when vehicles are running on the bridge should be analyzed and evaluated. Based on the method of vehicle-bridge coupling vibration theory, the finite element method (FEM) software ANSYS and multi-body dynamics software SIMPACK are adopted respectively to establish the finite element model for bridge and the multi-body vehicle. A co-simulation method is employed to investigate the vehicle-bridge coupling vibration for the transit system. The traffic operation factors, including train formation, track irregularity and tire stiffness, are incorporated into the models separately to analyze the bridge and vehicle responses. The results show that the coupling of dynamic effects of the suspended monorail system between vehicle and bridge are significant in the case studied, and it is strongly suggested to take necessary measures for vibration suppression. The simulation of track irregularity is a critical factor for its vibration safety, and the track irregularity of A-level road roughness negatively influences the system vibration safety.

  3. Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention.

    Science.gov (United States)

    Madder, Ryan D; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

    Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Among 336 cases (86.6% manual, 13.4% robotic) performed over 30weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, probotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (probotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (probotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Muscular contribution to low-back loading and stiffness during standard and suspended push-ups.

    Science.gov (United States)

    Beach, Tyson A C; Howarth, Samuel J; Callaghan, Jack P

    2008-06-01

    Push-up exercises are normally performed to challenge muscles that span upper extremity joints. However, it is also recognized that push-ups provide an effective abdominal muscle challenge, especially when the hands are in contact with a labile support surface. The purpose of this study was to compare trunk muscle activation levels and resultant intervertebral joint (IVJ) loading when standard and suspended push-ups were performed, and to quantify and compare the contribution of trunk muscles to IVJ rotational stiffness in both exercises. Eleven recreationally trained male volunteers performed sets of standard and suspended push-ups. Upper body kinematic, kinetic, and EMG data were collected and input into a 3D biomechanical model of the lumbar torso to quantify lumbar IVJ loading and the contributions of trunk muscles to IVJ rotational stiffness. When performing suspended push-ups, muscles of the abdominal wall and the latissimus dorsi were activated to levels that were significantly greater than those elicited when performing standard push-ups (pups. Also directly resulting from the increased activation levels of the abdominal muscles and the latissimus dorsi during suspended push-ups was increased muscular contribution to lumbar IVJ rotational stiffness (pups appear to provide a superior abdominal muscle challenge. However, for individuals unable to tolerate high lumbar IVJ compressive loads, potential benefits gained by incorporating suspended push-ups into their resistance training regimen may be outweighed by the risk of overloading low-back tissues.

  5. Recent changes of suspended sediment yields in the Upper Yangtze River and its headwater tributaries

    Science.gov (United States)

    Zhang, X.; Tang, Q.; Long, Y.; He, X.; Wen, A.

    2015-03-01

    Suspended sediment yields in the Upper Yangtze River and its four headwater tributaries (i.e. Jinsha, Min, Jialing and Wu) have declined significantly during recent decades. Compared with 1956-1970, mean annual suspended sediment yield during 2001-2011 was reduced by 84% in the Upper Yangtze River at Yichang, by 34% in the Jinsha at Pingshan, by 84% in the Jialing at Beibei, by 75% in the Wu at Wulong, and by 48% in the Min at Gaochang. Linking these observed decadal changes of runoff discharge and suspended sediment load to dam construction and multiple environmental rehabilitation projects (e.g. soil-water conservation, reforestation) during the past decades, it can be concluded that the construction of large dams on the main stem and major tributaries of the Upper Yangtze River has played a principal role in the reduction of fluvial suspended sediment yields, while the environment rehabilitation projects may make limited contributions to the changes in suspended sediment yields, except for the Jialing River.

  6. Recent changes of suspended sediment yields in the Upper Yangtze River and its headwater tributaries

    Directory of Open Access Journals (Sweden)

    X. Zhang

    2015-03-01

    Full Text Available Suspended sediment yields in the Upper Yangtze River and its four headwater tributaries (i.e. Jinsha, Min, Jialing and Wu have declined significantly during recent decades. Compared with 1956–1970, mean annual suspended sediment yield during 2001–2011 was reduced by 84% in the Upper Yangtze River at Yichang, by 34% in the Jinsha at Pingshan, by 84% in the Jialing at Beibei, by 75% in the Wu at Wulong, and by 48% in the Min at Gaochang. Linking these observed decadal changes of runoff discharge and suspended sediment load to dam construction and multiple environmental rehabilitation projects (e.g. soil-water conservation, reforestation during the past decades, it can be concluded that the construction of large dams on the main stem and major tributaries of the Upper Yangtze River has played a principal role in the reduction of fluvial suspended sediment yields, while the environment rehabilitation projects may make limited contributions to the changes in suspended sediment yields, except for the Jialing River.

  7. Surface clogging process modeling of suspended solids during urban stormwater aquifer recharge.

    Science.gov (United States)

    Wang, Zijia; Du, Xinqiang; Yang, Yuesuo; Ye, Xueyan

    2012-01-01

    Aquifer recharge, which uses urban stormwater, is an effective technique to control the negative effects of groundwater over-exploitation, while clogging problems in infiltration systems remain the key restricting factor in broadening its practice. Quantitative understanding of the clogging process is still very poor. A laboratory study was conducted to understand surface physical clogging processes, with the primary aim of developing a model for predicting suspended solid clogging processes before aquifer recharge projects start. The experiments investigated the clogging characteristics of different suspended solid sizes in recharge water by using a series of one-dimensional fine quartz sand columns. The results showed that the smaller the suspended particles in recharge water, the farther the distance of movement and the larger the scope of clogging in porous media. Clogging extents in fine sand were 1 cm, for suspended particle size ranging from 0.075 to 0.0385 mm, and 2 cm, for particles less than 0.0385 mm. In addition, clogging development occurred more rapidly for smaller suspended solid particles. It took 48, 42, and 36 hr respectively, for large-, medium-, and small-sized particles to reach pre-determined clogging standards. An empirical formula and iteration model for the surface clogging evolution process were derived. The verification results obtained from stormwater recharge into fine sand demonstrated that the model could reflect the real laws of the surface clogging process.

  8. Geospatial approach towards enumerative analysis of suspended sediment concentration for Ganges-Brahmaputra Bay

    Science.gov (United States)

    Pandey, Palak; Kunte, Pravin D.

    2016-10-01

    This study presents an easy, modular, user-friendly, and flexible software package for processing of Landsat 7 ETM and Landsat 8 OLI-TIRS data for estimating suspended particulate matter concentrations in the coastal waters. This package includes 1) algorithm developed using freely downloadable SCILAB package, 2) ERDAS Models for iterative processing of Landsat images and 3) ArcMAP tool for plotting and map making. Utilizing SCILAB package, a module is written for geometric corrections, radiometric corrections and obtaining normalized water-leaving reflectance by incorporating Landsat 8 OLI-TIRS and Landsat 7 ETM+ data. Using ERDAS models, a sequence of modules are developed for iterative processing of Landsat images and estimating suspended particulate matter concentrations. Processed images are used for preparing suspended sediment concentration maps. The applicability of this software package is demonstrated by estimating and plotting seasonal suspended sediment concentration maps off the Bengal delta. The software is flexible enough to accommodate other remotely sensed data like Ocean Color monitor (OCM) data, Indian Remote Sensing data (IRS), MODIS data etc. by replacing a few parameters in the algorithm, for estimating suspended sediment concentration in coastal waters.

  9. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  10. Effect of liquid waste discharges from steam generating facilities

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, H.E. Jr.

    1977-09-01

    This report contains a summary of the effects of liquid waste discharges from steam electric generating facilities on the environment. Also included is a simplified model for use in approximately determining the effects of these discharges. Four basic fuels are used in steam electric power plants: three fossil fuels--coal, natural gas, and oil; and uranium--presently the basic fuel of nuclear power. Coal and uranium are expected to be the major fuels in future years. The following power plant effluents are considered: heat, chlorine, copper, total dissolved solids, suspended solids, pH, oil and grease, iron, zinc, chrome, phosphorus, and trace radionuclides.

  11. [Protective effects of Chinese herb-compound on cellular immunological function (correction of funcion) in tail-suspended rats].

    Science.gov (United States)

    Song, J P; Zhong, P; Wang, T; Wen, X L; Zhang, H; Shen, X Y

    2001-06-01

    Objective. To observe the protective effects of two kinds of Chinese herb-compounds (Dan-huang-ci compound and Shen-chuan-shu compound) on cellular immunology in tail-suspended rats. Method. The rats were divided into: 1) normal control group; 2) tail-suspended group; 3) tail-suspended + Dan-huang-ci compound; and 4) tail-suspended + Shen-chuan-shu compound. Ability of lymphocyte proliferation and production of IL-2 in rats in the four groups were compared after 21 d. Result. The immunological function of tail-suspended control group decreased significantly as compared with normal control group. Shen-chuan-shu compound could improve immunological function of tail-suspended rats obviously. Conclusion. Shen-chuan-shu compound could enhance cellular immunological function in rats under simulated weightlessness.

  12. Indirectly suspended droplet microextraction of water-miscible organic solvents by salting-out effect for the determination of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Daneshfar, Ali; Khezeli, Tahere

    2014-12-01

    A simple and low-cost method that indirectly suspended droplet microextraction of water-miscible organic solvents (ISDME) by salting-out effect before high-performance liquid chromatography and ultraviolet (HPLC-UV) detection was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in different samples. The ISDME is a combination of salting-out extraction of water-miscible organic solvent and directly suspended droplet microextraction (DSDME). Ninety-five microliters water-miscible organic solvent (1-propanol) was added to a 500-µL sample. A homogeneous solution was formed immediately. To produce a steady vortex at the top of the solution, the sample was agitated at 700 rpm using a magnetic stirrer. By the addition of ammonium sulfate (saturated solution) to the homogeneous solution, 1-propanol was separated and collected at the bottom of the steady vortex. Finally, 20 µL 1-propanol was injected into HPLC-UV. The effects of important parameters such as water-miscible organic solvent (type and volume), type of salt, and extraction time were evaluated. Under optimum conditions, the method has a good linear calibration range (0.1 µg/L-300 µg/L), coefficients of determination (R(2) > 0.998), low limits of detection (between 0.02 µg/L and 0.27 µg/L), and acceptable recovery (>85.0%). © 2014 SETAC.

  13. Suspended Liquid Subtractive Lithography: One-step generation of 3D channel geometries in viscous curable polymer matrices

    National Research Council Canada - National Science Library

    D Helmer; A Voigt; S Wagner; N Keller; K Sachsenheimer; F Kotz; T M Nargang; B E Rapp

    2017-01-01

    The miniaturization of synthesis, analysis and screening experiments is an important step towards more environmentally friendly chemistry, statistically significant biology and fast and cost-effective medicinal assays...

  14. Delivery of esomeprazole magnesium through nasogastric and gastrostomy tubes using an oral liquid vehicle as a suspending agent in vitro.

    Science.gov (United States)

    Shah, Sachin A; Sander, Stephen; Coleman, Craig I; White, C Michael

    2006-10-01

    The optimal delivery medium for esomeprazole magnesium enteric-coated pellets dispersed in various concentrations of Ora-Plus suspension through commonly used nasogastric and gastrostomy tubes using a previously used standardized in vitro protocol was studied. The study was conducted in two phases. In phase A, 60 size 14 French nasogastric tubes were used to compare esomeprazole pellet delivery via tap water or 30, 50, or 70% Ora-Plus concentrations (15 tubes for each). In phase B, tap water and the concentration that yielded the best pellet delivery from phase A were used with the narrower size 8 and shorter size 20 French tubes. In both phases, the appropriate volume of water was added. All capsules were assumed to have 1,240 pellets. At the end of each administration, pellet retention counts were performed. The results showed excellent delivery of esomeprazole pellets using water as a medium for tube delivery. When compared with tap water as a delivery medium, no differences in pellet retention were observed when 30% and 50% Ora-Plus were used; thus, these Ora-Plus concentrations are feasible alternatives to tap water for nasogastric tube delivery of esomeprazole pellets. Administration of esomeprazole magnesium enteric-coated pellets dispersed in tap water or Ora-Plus through size 14 French nasogastric tubes in vitro delivered over 99% of capsule contents, regardless of the Ora-Plus concentration used. For immediate bedside administration, Ora-Plus at 50% concentration is a feasible alternative to water when delivering the pellets through size 14 French tubes, while 30% Ora-Plus is an alternative to water for all tubes studied.

  15. Flow modelling to estimate suspended sediment travel times for two Canadian Deltas

    Directory of Open Access Journals (Sweden)

    S. R. Fassnacht

    2000-01-01

    Full Text Available The approximate travel times for suspended sediment transport through two multi-channel networks are estimated using flow modelling. The focus is on the movement of high sediment concentrations that travel rapidly downstream. Since suspended sediment transport through river confluences and bifurcation movement is poorly understood, it is assumed that the sediment moves at approximately the average channel velocity during periods of high sediment load movement. Calibration of the flow model is discussed, with an emphasis on the incorporation of cross-section data, that are not referenced to a datum, using a continuous water surface profile. Various flow regimes are examined for the Mackenzie and the Slave River Deltas in the Northwest Territories, Canada, and a significant variation in travel times is illustrated. One set of continuous daily sediment measurements throughout the Mackenzie Delta is used to demonstrate that the travel time estimates are reasonable. Keywords: suspended sediment; multi-channel river systems; flow modelling; sediment transport

  16. Field calibration of optical sensors for measuring suspended sediment concentration in the western Mediterranean

    Directory of Open Access Journals (Sweden)

    J. Guillén

    2000-12-01

    Full Text Available The water turbidity measured with optical methods (transmittance and backscattering is usually expressed as beam attenuation coefficient (BAC or formazin turbidity units (FTU. The transformation of these units to volumetric suspended sediment concentration (SSC units is not straightforward, and accurate calibrations are required in order to obtain valuable information on suspended sediment distributions and fluxes. In this paper, data from field calibrations between BAC, FTU and SSC are presented and best-fit calibration curves are shown. These calibrations represent an average from different marine environments of the western Mediterranean (from estuary to continental slope. However, the general curves can only be applied for descriptive or semi-quantitative purposes. Comparison of turbidity measurements using the same sensor with different calibration ranges shows the advantage of simultaneously combining two instruments calibrated in different ranges when significant changes in suspended sediment concentrations are expected.

  17. A Suspended Stripline Frequency Tripler Using a Left-Handed Nonlinear Transmission Line

    Directory of Open Access Journals (Sweden)

    In Bok Kim

    2015-01-01

    Full Text Available A suspended stripline frequency tripler using a left-handed nonlinear transmission line (LH NLTL is presented. The proposed tripler using the LH NLTL is composed of a series of varactor diodes, shunt inductances, and a high-pass filter implemented with suspended stripline (SSL. An ultrawideband microstrip-to-suspended stripline transition is also utilized. The fabricated LH NLTL provides the minimum insertion loss of 1.7 dB and the maximum insertion loss of 4.7 dB for a wide frequency band from 2.6 to 18 GHz. As a tripler, the measured minimum third harmonic conversion loss is 15.3 dB at an input frequency of 2.4 GHz and typically 17 dB from 2 to 3.1 GHz.

  18. Suspended graphene with periodic dimer nanostructure on Si cavities for surface-enhanced Raman scattering applications

    Science.gov (United States)

    Ho, Hsin-Chia; Nien, Li-Wei; Li, Jia-Han; Hsueh, Chun-Hway

    2017-04-01

    Periodic gold dimer nanoantennas on a one-atomic-layer graphene sheet elevated above Si cavities were fabricated to systematically study the effects of the cavity depth on surface-enhanced Raman scattering (SERS). The periodic trend of Raman intensity as a function of the cavity depth resulting from the interference effect between the plasmonic resonance of the gold dimer and the cavity resonance of the underlying Si cavity was observed, and the electric field was greatly enhanced compared with the non-suspended system. The finite-difference time-domain method was used to simulate the interaction between the electromagnetic wave and the suspended system and to verify the observed SERS response in experiments. Our work has the advantages of combining the superior properties of graphene with suspended metallic nanostructures to result in the enhanced electric field for SERS applications.

  19. Resonant tunnelling features in a suspended silicon nanowire single-hole transistor

    Energy Technology Data Exchange (ETDEWEB)

    Llobet, Jordi; Pérez-Murano, Francesc, E-mail: francesc.perez@csic.es, E-mail: z.durrani@imperial.ac.uk [Institut de Microelectrònica de Barcelona (IMB-CNM CSIC), Campus UAB, E-08193 Bellaterra, Catalonia (Spain); Krali, Emiljana; Wang, Chen; Jones, Mervyn E.; Durrani, Zahid A. K., E-mail: francesc.perez@csic.es, E-mail: z.durrani@imperial.ac.uk [Department of Electrical and Electronic Engineering, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Arbiol, Jordi [Institució Catalana de Recerca i Estudis Avançats (ICREA) and Institut Català de Nanociència i Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra, Catalonia (Spain); CELLS-ALBA Synchrotron Light Facility, 08290 Cerdanyola, Catalonia (Spain)

    2015-11-30

    Suspended silicon nanowires have significant potential for a broad spectrum of device applications. A suspended p-type Si nanowire incorporating Si nanocrystal quantum dots has been used to form a single-hole transistor. Transistor fabrication uses a novel and rapid process, based on focused gallium ion beam exposure and anisotropic wet etching, generating <10 nm nanocrystals inside suspended Si nanowires. Electrical characteristics at 10 K show Coulomb diamonds with charging energy ∼27 meV, associated with a single dominant nanocrystal. Resonant tunnelling features with energy spacing ∼10 meV are observed, parallel to both diamond edges. These may be associated either with excited states or hole–acoustic phonon interactions, in the nanocrystal. In the latter case, the energy spacing corresponds well with reported Raman spectroscopy results and phonon spectra calculations.

  20. Mutual relationships of suspended sediment, turbidity and visual clarity in New Zealand rivers

    Directory of Open Access Journals (Sweden)

    D. J. Ballantine

    2015-03-01

    Full Text Available Many river water quality monitoring programmes do not measure suspended particulate matter (SPM mass concentrations despite significant interest in its multiple effects on aquatic ecosystems. Regular monthly sampling usually intercepts rivers in baseflow when suspended sediment mass concentrations and fluxes are relatively low and not of particular interest. New Zealand’s National Rivers Water Quality Network (NRWQN is probably typical in not measuring SPM mass, although visual clarity and nephelometric turbidity are routinely measured. In order to better characterize SPM in NZ rivers, total suspended sediment (TSS was temporarily added to the NRWQN. Turbidity, visual clarity and TSS are mutually inter-related over all 77 sites, although with considerable data scatter. However, within individual rivers turbidity and visual clarity are typically fairly closely related to TSS and provide fair to excellent surrogates. Therefore, TSS need not be measured routinely because it can be estimated with sufficient precision for many purposes from visibility or turbidity.

  1. Starch industry wastewater-based stable Bacillus thuringiensis liquid formulations.

    Science.gov (United States)

    Brar, Satinder K; Verma, M; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2005-12-01

    Liquid formulations were developed from Bacillus thuringiensis (Bt)-fermented broths of starch industry wastewater (SIW) and of soya medium. Stability studies were carried out for 1 yr. Storage stability was tested by studying various physical and chemical (e.g., viscosity, particle size, corrosion, and suspendibility) and biological (e.g., microbial contamination, viable spores, and entomotoxicity) parameters at different pH levels and temperatures. Three suspending agents, sorbitol, sodium monophosphate, and sodium metabisulfite, were added to fermented broth in different concentrations. Sorbitol and sodium monophosphate in the ratio 3:1 was the best suspending agent combination for both formulations. Starch industry wastewater fermentation yielded cell and viable spore counts 10- and 4-fold greater than those from soya medium, respectively, and a 1.7-fold increase in entomotoxicity. However, both formulations started deteriorating at pH 6 and 6.5 and 40 and 50 degrees C. There were no signs of corrosion and microbial contamination in both types of formulations.

  2. [Modulatory Effect of Mouse Compact Bone-derived Suspending MSC on T Cells and It's Related Mechanisms].

    Science.gov (United States)

    Li, Xin; Wu, Wen-Qing; Ding, Li; Liu, Yuan-Lin; Mao, Ning; Zhang, Yi; Zhu, Heng; Ning, Shou-Bin

    2016-04-01

    To investigate the modulatory effect of the MSC derived from low attaching culture systems (suspending MSC) on T lymphocytes and the related mechanisms. The suspending MSC were generated from mouse compact bones by using low attaching plates and adherent cell culture flasks, respectively. The morphology of suspending MSC was observed under the inverted microscope and the cells were induced to differentiate into osteoblasts and adipocytes. Further, the surface antigen profile of MSC was analyzed with flow cytometry. In addition, the culture medium (CM) of suspending MSC and adherent MSC was collected and added into the activated T cell cultures before detection of the proliferation by CFSE assay. Moreover, the modulaory effects of the CM on the T cell-derived cytokines were detected by quantitative PCR. Also, the mRNA expression of cytokines of MSC was detected. The suspending MSC grew in floating cell spheres and differentiated into osteoblasts and adipocytes in the induction medium. Furthermore, the suspending MSC shared the typical immuno-phenotype with their adherent counterparts. In addition, the results of CFSE assay demonstrated that suspending MSC derived CM suppressed ConA induced T cell proliferation. The results of quantitative PCR revealed that suspending MSC expressed transforming factor β1 and interleukin-6 at a higher level and suppressed the T cell expressing interferon γ and interleukine-17A. The suspending MSC exerted an unique modulatoy effect on T cells, which is quite different to adherent MSC.

  3. From Funding Liquidity to Market Liquidity

    DEFF Research Database (Denmark)

    Dick-Nielsen, Jens; Lund, Jesper; Gyntelberg, Jacob

    This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers......' ability to obtain funding. This effect holds true across both long and short term, government and covered bonds. We use MiFID data which provides a complete transaction level dataset for the Danish market covering both the subprime crisis and the Euro sovereign crisis. Furthermore, we verify the findings...... for other European government bonds using MTS data. The findings suggest that regulatory bond based liquidity buffers for banks will have limited effectiveness....

  4. Storage and residence time of suspended sediment in gravel bars of Difficult Run, VA

    Science.gov (United States)

    George, J.; Benthem, A.; Pizzuto, J. E.; Skalak, K.

    2016-12-01

    Reducing the export of suspended sediment is an important consideration for restoring water quality to the Chesapeake Bay, but sediment budgets for in-channel landforms are poorly constrained. We quantified fine (mapped in a 150m headwater reach at Miller Heights (bankfull width 11m; total bar volume 114 m3) and 6 gravel bars were mapped in a 160m reach downstream near Leesburg Pike (bankfull width 19m; total bar volume 210 m3). Grain size analyses of surface and subsurface samples from 2 bars at each reach indicate an average suspended sediment content of 55%, suggesting a total volume of suspended sediment stored in the mapped bars to be 178 m3, or 283000 kg, comprising 5% of the average annual suspended sediment load of the two study reaches. Estimates of the annual bedload flux at Miller Heights based on stream gaging records and the Wilcock-Crowe bedload transport equation imply that the bars are entirely reworked at least annually. Scour chains installed in 2 bars at each site (a total of 50 chains) recorded scour and fill events during the winter and spring of 2016. These data indicate that 38% of the total volume of the bars is exchanged per year, for a residence time of 2.6 ± 1.2 years, a value we interpret as the residence time of suspended sediment stored in the bars. These results are supported by mapping of topographic changes derived from structure-from-motion analyses of digital aerial imagery. Storage in alluvial bars therefore represents a significant component of the suspended sediment budget of mid-Atlantic streams.

  5. [Impacts of Sediment Disturbance on the Distribution of Suspended Particle Size and Phosphorus].

    Science.gov (United States)

    Guo, Jun-rui; Li, Da-peng; Liu, Yan-jian

    2016-04-15

    To clarify the influence of the sediments disturbance on the particle size distribution of suspended solids, and the influence of particle distribution on the forms of dissolved phosphorous in the overlaying water, the sediments and overlying water from Meiliang Bay, Taihu Lake, were used to conduct the indoor simulation experiments to investigate the particle size of suspended solids according to the Ubbelobde particle size criteria and the distribution of phosphorus compounds in the overlying water under the disturbance circumstances. The results indicated that the average proportions of small (0-10 microm), middle (10-20 microm) and large (> or = 20 microm) diameter particles presented different trends of increasing, decreasing and staying stable, respectively. It indicated the possible transformation of particle size of suspended solids from small-middle diameter to large diameter. In addition, the data of DTP/TP and DIP/TP showed a periodical variation with the corresponding periodical variety of particle diameter in suspended solids, while ns obvious variety of DTP and DIP was observed. It suggested that disturbance enhanced the ability of phosphorus immobilization by suspended solids. On the other band, the percentages of DTP in TP and DIP in TP were 19% and 13% under the disturbance, respectively, and they were obviously lower than those (DTP/TP, 80% and DIP/TP, 69% ) in the control. It indicated that tbs transformation of particle size of suspended solids from small-middle diameter to large diameter due to disturbance was in favor of tbe adsorption and sedimentation of dissolved phosphorus. Accordingly, the formation of particle phosphorus was enhanced. Therefore, it delayed the development of eutrophication in the water body.

  6. Liquid Effluent Retention Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Liquid Effluent Retention Facility (LERF) is located in the central part of the Hanford Site. LERF is permitted by the State of Washington and has three liquid...

  7. Combined main-chain/side-chain ionic liquid crystalline polymer based on ‘jacketing’ effect: Design, synthesis, supra-molecular self-assembly and photophysical properties

    Directory of Open Access Journals (Sweden)

    L. Weng

    2015-06-01

    Full Text Available Reasonably fabricating ordered structures of ionic polymers is very important for the development of novel functional materials. By combining the ions and liquid cry stalline polymer, we successfully designed and synthesized a series of novel combined main-chain/side-chain ionic liquid crystalline polymer (MCSC-ILCPs containing imidazolium groups and different counter-anions, poly (2,5-bis{[6-(4-butoxy-4'-imidazolium biphenylhexyl]oxycarbonyl}styrene salts poly(BImBHCS-X with the following types of counter-anions (Br¯, BF4¯, PF6¯ and TFSI¯. Combined technologies confirmed the chemical structures of the monomers and polymers with imidazolium cation and different counter-anions. Differential scanning calorimetry (DSC, polarized light microscopy (PLM and one- and two-dimensional wide-angle X-ray diffraction (1D and 2D WAXD results illustrated that the LC structures and the transitions of ordered structures depended on the nature of the counter-anion employed. The polymers with Br¯ and BF4¯ counter-anions exhibited smectic A (SmA LC behavior below the isotropic temperature. The another one, poly(BImBHCS–TFSI with the large volume of the TFSI¯ anion destroyed the packing of the LC ordered structure resulting in an amorphous structure. The photophysical properties of the polymers prepared can be adjusted by tuning the ionic interaction of the polymers by switching the counter-anion.

  8. High Average Power Mid-infrared Supercontinuum Generation in a Suspended Core Chalcogenide Fiber

    DEFF Research Database (Denmark)

    Møller, Uffe Visbech; Yu, Yi; Petersen, Christian Rosenberg

    2014-01-01

    Mid-infrared supercontinuum spanning from 2.0 to 6.1 μm is generated in a 9 cm suspended core chalcogenide fiber by pumping close to the fiber zero-dispersion wavelength at 3.5 μm with an OPA system......Mid-infrared supercontinuum spanning from 2.0 to 6.1 μm is generated in a 9 cm suspended core chalcogenide fiber by pumping close to the fiber zero-dispersion wavelength at 3.5 μm with an OPA system...

  9. Fabrication and Measurement of a Suspended Nanochannel Microbridge Resonator Monolithically Integrated with CMOS Readout Circuitry

    Directory of Open Access Journals (Sweden)

    Gabriel Vidal-Álvarez

    2016-03-01

    Full Text Available We present the fabrication and characterization of a suspended microbridge resonator with an embedded nanochannel. The suspended microbridge resonator is electrostatically actuated, capacitively sensed, and monolithically integrated with complementary metal-oxide-semiconductor (CMOS readout circuitry. The device is fabricated using the back end of line (BEOL layers of the AMS 0.35 μm commercial CMOS technology, interconnecting two metal layers with a contact layer. The fabricated device has a 6 fL capacity and has one of the smallest embedded channels so far. It is able to attain a mass sensitivity of 25 ag/Hz using a fully integrable electrical transduction.

  10. The mineralogy and trace element constituents of suspended stream sediments of the Linggi River Basin, Malaysia

    Science.gov (United States)

    Nather Khan, I. S. A.

    The mineralogy and trace element concentrations of suspended stream sediments were determined at selected stations in the Linggi River Basin, Malaysia, while conducting an intensive study on water quality and a biological assessment of water pollution in the basin. The minerals that were identified from the X-ray patterns of the suspended stream sediments are kaolinite, mica, feldspar and quartz. Kaolinite was the most abundant mineral, followed by mica. By considering mean concentrations of various trace elements, aluminum and manganese were the most abundant elements. Higher concentrations of copper and zinc at some stations were due to pollutants from the nearby Senawang Industrial Estate.

  11. Static and dynamic stability of the guidance force in a side-suspended HTS maglev system

    Science.gov (United States)

    Zhou, Dajin; Cui, Chenyu; Zhao, Lifeng; Zhang, Yong; Wang, Xiqing; Zhao, Yong

    2017-02-01

    The static and dynamic stability of the guidance force in a side-suspended HTS-PMG (permanent magnetic guideway) system were studied theoretically and experimentally. It is found that there are two types of guidance force that exist in the HTS-PMG system, which are sensitive to the levitation gap and the arrangement of YBCO bulks around the central axis of the PMG. An optimized YBCO array was used to stabilize the system, which enabled a side-suspended HTS-PMG maglev vehicle to run stably at 102 km h-1 on a circular test track with 6.5 m in diameter.

  12. Quantifying suspended sediment loads delivered to Cheney Reservoir, Kansas: Temporal patterns and management implications

    Science.gov (United States)

    Stone, Mandy L.; Juracek, Kyle E.; Graham, Jennifer; Foster, Guy

    2015-01-01

    Cheney Reservoir, constructed during 1962 to 1965, is the primary water supply for the city of Wichita, the largest city in Kansas. Sediment is an important concern for the reservoir as it degrades water quality and progressively decreases water storage capacity. Long-term data collection provided a unique opportunity to estimate the annual suspended sediment loads for the entire history of the reservoir. To quantify and characterize sediment loading to Cheney Reservoir, discrete suspended sediment samples and continuously measured streamflow data were collected from the North Fork Ninnescah River, the primary inflow to Cheney Reservoir, over a 48-year period. Continuous turbidity data also were collected over a 15-year period. These data were used together to develop simple linear regression models to compute continuous suspended sediment concentrations and loads from 1966 to 2013. The inclusion of turbidity as an additional explanatory variable with streamflow improved regression model diagnostics and increased the amount of variability in suspended sediment concentration explained by 14%. Using suspended sediment concentration from the streamflow-only model, the average annual suspended sediment load was 102,517 t (113,006 tn) and ranged from 4,826 t (5,320 tn) in 1966 to 967,569 t (1,066,562 tn) in 1979. The sediment load in 1979 accounted for about 20% of the total load over the 48-year history of the reservoir and 92% of the 1979 sediment load occurred in one 24-hour period during a 1% annual exceedance probability flow event (104-year flood). Nearly 60% of the reservoir sediment load during the 48-year study period occurred in 5 years with extreme flow events (9% to 1% annual exceedance probability, or 11- to 104-year flood events). A substantial portion (41%) of sediment was transported to the reservoir during five storm events spanning only eight 24-hour periods during 1966 to 2013. Annual suspended sediment load estimates based on streamflow were, on

  13. Growth and energetics in Spisula subtruncata (Da Costa) and the effect of suspended bottom material

    DEFF Research Database (Denmark)

    Møhlenberg, F.; Kiørboe, Thomas

    1981-01-01

    The influence of suspended bottom material (0-25 mg/l) and algal cells (Phaeodactylum tricornutum) (0-500 .mu.g dry org wt[organic weight]/l) on clearance, growth and energetics in S. subtruncata (da Costa) was studied. Clearance and respiration rate were independent of concentrations of algae...... bottom material on growth is due to a higher efficiency of assimilation of the ingested algae and/or the utilization of organic matter in the suspended bottom material. The efficiency of algal assimilation decreased from 76% at a low (150 .mu.g dry org wt/l) to 33% at a high (500 .mu.g) algal...

  14. Serum-Free Cryopreservation of Five Mammalian Cell Lines in Either a Pelleted or Suspended State

    Directory of Open Access Journals (Sweden)

    Corsini Joe

    2004-01-01

    Full Text Available Herein we have explored two practical aspects of cryopreserving cultured mammalian cells during routine laboratory maintenance. First, we have examined the possibility of using a serum-free, hence more affordable, cryopreservative. Using five mammalian lines (Crandell Feline Kidney, MCF7, A72, WI 38 and NB324K, we found that the serum-free alternative preserves nearly as efficiently as the serum-containing preservatives. Second, we compared cryostorage of those cells in suspended versus a pellet form using both aforementioned cryopreservatives. Under our conditions, cells were in general recovered equally well in a suspended versus a pellet form.

  15. Laser-induced incandescence of suspended particles as a source of excitation of dye luminescence

    CERN Document Server

    Zelensky, S

    2003-01-01

    The interaction of pulsed YAG-Nd sup 3 sup + laser radiation with submicron light-absorbing particles suspended in an aqueous solution of Rhodamine 6G is investigated experimentally. The experiments demonstrate that the laser-induced incandescence of suspended particles excites the luminescence of the dissolved dye molecules. The mechanism of the luminescence excitation consists in the reabsorption of the thermal radiation within the volume of the sample cell. On the ground of this mechanism of excitation, a method of measurement of the luminescence quantum yield is proposed and realized. The method requires the knowledge of the geometrical parameters of the cell and does not require the use of reference samples.

  16. Experimental investigations of heat transfer in thermo active building systems in combination with suspended ceilings

    DEFF Research Database (Denmark)

    Alvarez, Maria Alonso; Hviid, Christian Anker; Weitzmann, Peter

    2014-01-01

    buildings to cover acoustic requirements hinders the use of TABS. To measure the reduction of the heat capacity, several experiments are performed in a room equipped with TABS in the upper deck and mixing ventilation. The heat transfer is measured for different suspended ceiling covering percentages...... that the ventilation rate has a high influence on the convective heat capacity. When the ventilation rate is increased from 1.7 h-1 to 2.9 h-1, the heat transfer coefficient increases up to 16% for the same occupancy and suspended ceiling layout....

  17. Dynamics of Single Chains of Suspended Ferrofluid Particles

    Science.gov (United States)

    Cutillas, S.; Liu, J.

    1999-01-01

    We present an experimental study of the dynamics of isolated chains made of super-paramagnetic particles under the influence of a magnetic field. The motivation of this work is to understand if the chain fluctuations exist and, if it does, how does the fluctuation affect chain aggregation. We find that single chains strongly fluctuate and that the characteristic frequency of their fluctuations is inversely proportional to the magnetic field strength. The higher the field the lower the characteristic frequency of the chain fluctuations. In the high magnetic field limit, chains behave like rigid rods without any internal motions. In this work, we used ferrofluid particles suspended in water. These particles do not have any intrinsic magnetization. Once a magnetic field is applied, a dipole moment is induced in each particle, proportional to the magnetic field. A dipolar magnetic interaction then occurs between particles. If dipole-dipole magnetic energy is higher than the thermal energy, the result is a structure change inside the dipolar fluid. The ratio of these two energies is expressed by a coupling constant lambda as: lambda = (pi(a(exp 3))(chi(exp 2))(mu(sub 0))(H(sub 0))(exp 2))/18kT Where a is the particle radius, mu(sub 0) is the vacuum magnetic permeability, H(sub 0) the applied magnetic field, k the Boltzmann constant and T the absolute temperature. If lambda > 1, magnetic particles form chains along the field direction. The lateral coalescence of several chains may form bigger aggregates especially if the particle volume fraction is high. While many studies and applications deal with the rheological properties and the structural changes of these dipolar fluids, this work focuses on the understanding of the chain dynamics. In order to probe the chain dynamics, we used dynamic light scattering (DLS) in self-beating mode as our experimental technique. The experimental geometry is such that the scattering plane is perpendicular to the magnetic field

  18. Instantaneous Liquid Interfaces

    OpenAIRE

    Willard, Adam P.; Chandler, David

    2009-01-01

    We describe and illustrate a simple procedure for identifying a liquid interface from atomic coordinates. In particular, a coarse grained density field is constructed, and the interface is defined as a constant density surface for this coarse grained field. In applications to a molecular dynamics simulation of liquid water, it is shown that this procedure provides instructive and useful pictures of liquid-vapor interfaces and of liquid-protein interfaces.

  19. Spatial distribution of organic contaminants in three rivers of Southern England bound to suspended particulate material and dissolved in water.

    Science.gov (United States)

    Wilkinson, John L; Hooda, Peter S; Swinden, Julian; Barker, James; Barton, Stephen

    2017-09-01

    The spatial distribution of pharmaceuticals, personal care products (PPCPs) and other emerging contaminants (ECs) such as plasticisers, perflourinated compounds (PFCs) and illicit drug metabolites in water and bound to suspended particulate material (SPM) is not well-understood. Here, we quantify levels of thirteen selected contaminants in water (n=88) and their partition to suspended particulate material (SPM, n=16) in three previously-unstudied rivers of Greater London and Southern England during a key reproduction/spawning period. Analysis was conducted using an in-house validated method for Solid Phase Extraction followed by High-Performance Liquid Chromatography-Tandem Mass-Spectrometry. Analytes were extracted from SPM using an optimised method for ultrasonic-assisted solvent extraction. Detection frequencies of contaminants dissolved in water ranged from 3% (ethinylestradiol) to 100% (bisphenol-A). Overall mean concentrations in the aqueous-phase ranged from 14.7ng/L (benzoylecgonine) to 159ng/L (bisphenol-A). Sewage treatment works (STW) effluent was the predominant source of pharmaceuticals, while plasticisers/perfluorinated compounds may additionally enter rivers via other sources. In SPM, detection frequencies ranged from 44% (PFOA) to 94% (hydroxyacetophenone). Mean quantifiable levels of analytes bound to SPM ranged from 13.5ng/g dry SPM (0.33ng bound/L water) perfluorononanoic acid to 2830ng/g dry SPM (14.3ng bound/L water) perfluorooctanesulfonic acid. Long chain (>C7) amphipathic and acidic PFCs were found to more preferentially bind to SPM than short chain PFCs and other contaminants (Kd=34.1-75.5 vs work (n=104) enabled ANOVA followed by Tukey HSD post-hoc tests to establish significant trends in PPCP/EC spatial distribution from headwaters through downstream stretches of studied rivers. Novel findings include environmental Kd calculations, the occurrence of contaminants in river headwaters, increases in contaminant metabolite concentrations

  20. The effects of sample scheduling and sample numbers on estimates of the annual fluxes of suspended sediment in fluvial systems

    Science.gov (United States)

    Horowitz, Arthur J.; Clarke, Robin T.; Merten, Gustavo Henrique

    2015-01-01

    Since the 1970s, there has been both continuing and growing interest in developing accurate estimates of the annual fluvial transport (fluxes and loads) of suspended sediment and sediment-associated chemical constituents. This study provides an evaluation of the effects of manual sample numbers (from 4 to 12 year−1) and sample scheduling (random-based, calendar-based and hydrology-based) on the precision, bias and accuracy of annual suspended sediment flux estimates. The evaluation is based on data from selected US Geological Survey daily suspended sediment stations in the USA and covers basins ranging in area from just over 900 km2 to nearly 2 million km2 and annual suspended sediment fluxes ranging from about 4 Kt year−1 to about 200 Mt year−1. The results appear to indicate that there is a scale effect for random-based and calendar-based sampling schemes, with larger sample numbers required as basin size decreases. All the sampling schemes evaluated display some level of positive (overestimates) or negative (underestimates) bias. The study further indicates that hydrology-based sampling schemes are likely to generate the most accurate annual suspended sediment flux estimates with the fewest number of samples, regardless of basin size. This type of scheme seems most appropriate when the determination of suspended sediment concentrations, sediment-associated chemical concentrations, annual suspended sediment and annual suspended sediment-associated chemical fluxes only represent a few of the parameters of interest in multidisciplinary, multiparameter monitoring programmes. The results are just as applicable to the calibration of autosamplers/suspended sediment surrogates currently used to measure/estimate suspended sediment concentrations and ultimately, annual suspended sediment fluxes, because manual samples are required to adjust the sample data/measurements generated by these techniques so that they provide depth-integrated and cross

  1. Tracing suspended sediment sources in the Upper Sangamon River Basin using conservative and non-conservative tracers

    Science.gov (United States)

    Yu, M.; Rhoads, B. L.; Stumpf, A.

    2015-12-01

    As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois, USA. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook from five potential sources: farmland, forests, floodplains, river banks, and grasslands. Event-based and accumulated suspended sediment samples were collected by ISCO automatic pump samplers and in situ suspended sediment samplers and from the stream at watershed outlet. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an un-mixing model, was employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and radionuclides from soil samples were used as potential tracers. Our preliminary results indicate that the majority of suspended sediment is derived from floodplains in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland

  2. Impact of pig slurry amendments on phosphorus, suspended sediment and metal losses in laboratory runoff boxes under simulated rainfall.

    Science.gov (United States)

    O'Flynn, C J; Fenton, O; Wilson, P; Healy, M G

    2012-12-30

    Losses of phosphorus (P) when pig slurry applications to land are followed by a rainfall event or losses from soils with high P contents can contribute to eutrophication of receiving waters. The addition of amendments to pig slurry spread on high P Index soils may reduce P and suspended sediment (SS) losses. This hypothesis was tested at laboratory-scale using runoff boxes under simulated rainfall conditions. Intact grassed soil samples, 100 cm-long, 22.5 cm-wide and 5 cm-deep, were placed in runoff boxes and pig slurry or amended pig slurry was applied to the soil surface. The amendments examined were: (1) commercial grade liquid alum (8% Al(2)O(3)) applied at a rate of 0.88:1 [Al:total phosphorus (TP)] (2) commercial-grade liquid ferric chloride (38% FeCl(3)) applied at a rate of 0.89:1 [Fe:TP] and (3) commercial-grade liquid poly-aluminium chloride (PAC) (10% Al(2)O(3)) applied at a rate of 0.72:1 [Al:TP]. The grassed soil was then subjected to three rainfall events (10.3 ± 0.15 mm h(-1)) at time intervals of 48, 72, and 96 h following slurry application. Each sod received rainfall on 3 occasions. Results across three rainfall events showed that for the control treatment, the average flow weighted mean concentration (FWMC) of TP was 0.61 mg L(-1), of which 31% was particulate phosphorus (PP), and the average FWMC of SS was 38.1 mg L(-1). For the slurry treatment, there was an average FWMC of 2.2 mg TP L(-1), 47% of which was PP, and the average FWMC of SS was 71.5 mg L(-1). Ranked in order of effectiveness from best to worst, PAC reduced the average FWMC of TP to 0.64 mg L(-1) (42% PP), FeCl(3) reduced TP to 0.91 mg L(-1) (52% PP) and alum reduced TP to 1.08 mg L(-1) (56% PP). The amendments were in the same order when ranked for effectiveness at reducing SS: PAC (74%), FeCl(3) (66%) and alum (39%). Total phosphorus levels in runoff plots receiving amended slurry remained above those from soil only, indicating that, although incidental losses could be mitigated

  3. Nonuniform liquid-crystalline phases of parallel hard rod-shaped particles: From ellipsoids to cylinders

    Science.gov (United States)

    Martínez-Ratón, Y.; Velasco, E.

    2008-08-01

    In this article we consider systems of parallel hard superellipsoids, which can be viewed as a possible interpolation between ellipsoids of revolution and cylinders. Superellipsoids are characterized by an aspect ratio and an exponent α (shape parameter) which takes care of the geometry, with α=1 corresponding to ellipsoids of revolution, while α=∞ is the limit of cylinders. It is well known that, while hard parallel cylinders exhibit nematic, smectic, and solid phases, hard parallel ellipsoids do not stabilize the smectic phase, the nematic phase transforming directly into a solid as density is increased. We use computer simulation to find evidence that for α>=αc, where αc is a critical value which the simulations estimate to be approximately 1.2-1.3, the smectic phase is stabilized. This is surprisingly close to the ellipsoidal case. In addition, we use a density-functional approach, based on the Parsons-Lee approximation, to describe smectic and columnar orderings. In combination with a free-volume theory for the crystalline phase, a theoretical phase diagram is predicted. While some qualitative features, such as the enhancement of smectic stability for increasing α and the probable absence of a stable columnar phase, are correct, the precise location of coexistence densities is quantitatively incorrect.

  4. Crystalline Kitaev spin liquids

    Science.gov (United States)

    Yamada, Masahiko G.; Dwivedi, Vatsal; Hermanns, Maria

    2017-10-01

    Frustrated magnetic systems exhibit many fascinating phases. Prime among them are quantum spin liquids, where the magnetic moments do not order even at zero temperature. A subclass of quantum spin liquids called Kitaev spin liquids are particularly interesting, because they are exactly solvable, can be realized in certain materials, and show a large variety of gapless and gapped phases. Here we show that nonsymmorphic symmetries can enrich spin liquid phases, such that the low-energy spinon degrees of freedom form three-dimensional Dirac cones or nodal chains. In addition, we suggest a realization of such Kitaev spin liquids in metal-organic frameworks.

  5. Structural Transition in Liquid Crystal Bubbles Generated from Fluidic Nanocellulose Colloids.

    Science.gov (United States)

    Chu, Guang; Vilensky, Rita; Vasilyev, Gleb; Deng, Shengwei; Qu, Dan; Xu, Yan; Zussman, Eyal

    2017-07-17

    The structural transition in micrometer-sized liquid crystal bubbles (LCBs) derived from rod-like cellulose nanocrystals (CNCs) was studied. The CNC-based LCBs were suspended in nematic or chiral nematic liquid-crystalline CNCs, which generated topological defects and distinct birefringent textures around them. The ordering and structure of the LCBs shifted from a nematic to chiral nematic arrangement as water evaporation progressed. These packed LCBs exhibited a specific photonic cross-communication property that is due to a combination of Bragg reflection and bubble curvature and size. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Laser-induced forward transfer: Propelling liquids with light

    Science.gov (United States)

    Fernández-Pradas, J. M.; Florian, C.; Caballero-Lucas, F.; Sopeña, P.; Morenza, J. L.; Serra, P.

    2017-10-01

    Laser-induced forward transfer (LIFT) constitutes an interesting alternative to conventional printing techniques in microfabrication applications. Originally developed to print inorganic materials from solid films, it was later proved that LIFT was feasible for printing liquids as well, which substantially broadened the range of printable materials. Any material which can be suspended or dissolved in an ink can be in principle printed through LIFT. The principle of operation of LIFT relies on the localized absorption of a focused laser pulse in a thin film of the ink containing the material to print (donor). This results in the generation of a cavitation bubble which expansion displaces a fraction of the liquid around it, leading to the formation of a jet which propagates away the donor and towards the receiving substrate, placed at a short distance from the liquid free surface. The contact of the jet with this receiving substrate results in the deposition of a sessile droplet. Thus, each droplet results from a single laser pulse, and the generation of micropatterns is achieved through the printing of successive droplets. A similar ejection and deposition process is produced by generating a cavitation bubble below the surface of a liquid contained in a reservoir in the film-free laser printing configuration. In this work we review our main achievements on the laser printing of inks, paying special attention to the analysis of the liquid transfer dynamics and its correlation with the printing outcomes.

  7. Efflux time of soap bubbles and liquid spheres.

    Science.gov (United States)

    Grosse, A V

    1967-06-02

    The efflux time, T, of gas from soap bubbles of radius, R, through their blow tube of length, 1, and radius, p, is given by the equation see pdf for equation where eta is the viscosity of the gas and omicron the surface tension of the bubble solution, all in centimeter-gram-second units. Similar relations between time and diameter were established for the flow from one bubble to another or from one bubble within another. The same relations hold for the flow of liquid spheres, suspended in another liquid of equal density, following Plateau's classic method. They have been extended to the flow of spheres to cylinders and catenoids of rotation. In all these cases the driving force is the surface or interfacial tension, creating an excess pressure as defined by Laplace's equation.

  8. A liquid crystal biosensor for specific detection of antigens

    Directory of Open Access Journals (Sweden)

    Piotr Popov

    2016-05-01

    Full Text Available Following the principle of the enzyme-linked immunosorbent assay (ELISA pathogen detection method, we demonstrate specific sensing of goat Immunoglobulin G (IgG by a nematic liquid crystal material. Sensing occurs via the visually-striking realignment of a pre-fabricated liquid crystal film, suspended in grids and coated with biotinylated lipids followed by biotinylated anti-goat IgG. Realignment occurs when the targeted goat IgG is added to the cell, but not when rat or rabbit serum IgG is added to the same surface. In principle, this method can be generalized to provide an inexpensive, fast and sensitive prefabricated sensor for any pathogen.

  9. The effect of light direction and suspended cell concentrations on algal biofilm growth rates.

    Science.gov (United States)

    Schnurr, Peter J; Espie, George S; Allen, D Grant

    2014-10-01

    Algae biofilms were grown in a semicontinuous flat plate biofilm photobioreactor to study the effects of light direction and suspended algal cell populations on algal biofilm growth. It was determined that, under the growth conditions and biofilm thicknesses studied, light direction had no effect on long-term algal biofilm growth (26 days); however, light direction did affect the concentration of suspended algal cells by influencing the photon flux density in the growth medium in the photobioreactors. This suspended algal cell population affected short-term (7 days) algae cell recruitment and algal biofilm growth, but additional studies showed that enhanced suspended algal cell populations did not affect biofilm growth rates over the long term (26 days). Studying profiles of light transmittance through biofilms as they grew showed that most of the light became attenuated by the biomass after just a few days of growth (88 % after 3 days). The estimated biofilm thicknesses after these few days of growth were approximately 150 μm. The light attenuation data suggests that, although the biofilms grew to 700-900 μm, under these light intensities, only the first few hundred micrometers of the biofilm is receiving enough light to be photosynthetically active. We postulate that this photosynthetically active layer of the biofilm grows adjacent to the light source, while the rest of the biofilm is in a stationary growth phase. The results of this study have implications for algal biofilm photobioreactor design and operation.

  10. 9 CFR 201.11 - Suspended registrants; officers, agents, and employees.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Suspended registrants; officers, agents, and employees. 201.11 Section 201.11 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... partnership or corporation in which any such person has a substantial financial interest or exercises...

  11. Stable isotopes of carbon and nitrogen in suspended matter and sediments from the Godavari estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Arya, J.; Subbaiah, Ch.V.; Naidu, S.A.; Gawade, L.; PraveenKumar, P.; Reddy, N.P.C.

    of terrigeneous material toward the mouth of the estuary. A significant positive relationship exists between the delta sup(13)C of suspended and sediment, which indicates that these two organic carbon pools are likely coupled in the form of a significant exchange...

  12. Influence of sugars, pre-treatment with acid and suspending medium ...

    African Journals Online (AJOL)

    Change in the suspending medium from PBS to immunogold buffer did not alter the con-A reactivity of ST and SE. Interactions of lectins with microorganisms have great diagnostic clinical laboratory value in microbial typing, taxonomic classification and epidemiology. © 2007 International Formulae Group. All rights reserved ...

  13. Effect of anabolic steroids on overloaded and overloaded suspended skeletal muscle

    Science.gov (United States)

    Tsika, R. W.; Herrick, R. E.; Baldwin, K. M.

    1987-01-01

    The effect of treatment with an anabolic steroid (nandrolone decanoate) on the muscle mass, the subcellular protein content, and the myosin patterns of normal overloaded and suspended overloaded plantaris muscle in female rat was investigated, dividing rats into six groups: normal control (NC), overload (OV), OV steroid (OV-S), normal suspended (N-sus), OV suspended (OV-sus), and OV suspended steroid (OV-sus-S). Relative to control values, overload produced a sparing effect on the muscle weight of the OV-sus group as well as increases of muscle weight of the OV group; increased protein content; and an increased expression of slow myosin in both OV and OV-sus groups. Steroid treatment of OV animals did not after the response of any parameter analyzed for the OV group, but in the OV-sus group steroid treatment induced increases in muscle weight and in protein content of the OV-sus-S group. The treatment did not alter the pattern of isomyosin expression observed in the OV or the OV-sus groups. These result suggest that the steroid acts synergistically with functional overload only under conditions in which the effect of overload is minimized by suspension.

  14. Lithography-Free Fabrication of Silica Nanocylinders with Suspended Gold Nanorings for LSPR-Based Sensing

    DEFF Research Database (Denmark)

    Thilsted, Anil Haraksingh; Pan, Jesper Yue; Wu, Kaiyu

    2016-01-01

    areas, such as 8 in. wafers. The authors demonstrate that gold coated nanocylinders support localized surface plasmon resonances (LSPR) from visible to near infrared wavelengths. The plasmonic platform can be characterized as suspended gold nanorings and exhibits a sensitivity of 658 nm RIU-1...

  15. Limitations upon Legitimate Authority to Suspend and Expel K-12 Public School Students: A Moral Analysis

    Science.gov (United States)

    Ladenson, Robert F.

    2011-01-01

    This article presents a moral analysis of the limitations upon legitimate authority to suspend and expel students in K-12 public schools, and it brings this analysis to bear on a pair of difficult disciplinary cases. The analysis is grounded in a defense of a child's right to receive a public education. It identifies the minimum content of that…

  16. Impact of suspended solids concentration on sludge filterability in Full-scale membrane bioreactors

    NARCIS (Netherlands)

    Lousada Ferreira, M.D.C.; Van Lier, J.B.; Van der Graaf, J.H.J.M.

    2015-01-01

    The relation between activated sludge filterability and mixed liquor suspended solids (MLSS) concentration in membrane bioreactors (MBRs) is framed in a single hypothesis, explaining results seemingly contradictory. A total of 44 activated sludge samples were collected and analyzed on a variety of

  17. Report of meeting on measurement of suspended solids in the Meuse

    NARCIS (Netherlands)

    Joziasse, J.; Klaver, G.; Bakker, I.

    2004-01-01

    On June 19/20, 2007 a visit was paid to a suspended particulate matter (SPM) sampling and monitoring site in the Ourthe river (Liège region), between the confluence with the Vesdre river and the mouth of the Ourthe in the Meuse river. The next day, a workshop was organised in which backgrounds,

  18. Suspended-sediment loads in the lower Stillaguamish River, Snohomish County, Washington, 2014–15

    Science.gov (United States)

    Anderson, Scott A.; Curran, Christopher A.; Grossman, Eric E.

    2017-08-03

    Continuous records of discharge and turbidity at a U.S. Geological Survey (USGS) streamgage in the lower Stillaguamish River were paired with discrete measurements of suspended-sediment concentration (SSC) in order to estimate suspended-sediment loads over the water years 2014 and 2015. First, relations between turbidity and SSC were developed and used to translate the continuous turbidity record into a continuous estimate of SSC. Those concentrations were then used to predict suspended-sediment loads based on the current discharge record, reported at daily intervals. Alternative methods were used to in-fill a small number of days with either missing periods of turbidity or discharge records. Uncertainties in our predictions at daily and annual time scales were estimated based on the parameter uncertainties in our turbidity-SSC regressions. Daily loads ranged from as high as 121,000 tons during a large autumn storm to as low as –56 tons, when tidal return flow moved more sediment upstream than river discharge did downstream. Annual suspended-sediment loads for both water years were close to 1.4 ± 0.2 million tons.

  19. Characterization of suspended bacteria from processing units in an advanced drinking water treatment plant of China.

    Science.gov (United States)

    Wang, Feng; Li, Weiying; Zhang, Junpeng; Qi, Wanqi; Zhou, Yanyan; Xiang, Yuan; Shi, Nuo

    2017-05-01

    For the drinking water treatment plant (DWTP), the organic pollutant removal was the primary focus, while the suspended bacterial was always neglected. In this study, the suspended bacteria from each processing unit in a DWTP employing an ozone-biological activated carbon process was mainly characterized by using heterotrophic plate counts (HPCs), a flow cytometer, and 454-pyrosequencing methods. The results showed that an adverse changing tendency of HPC and total cell counts was observed in the sand filtration tank (SFT), where the cultivability of suspended bacteria increased to 34%. However, the cultivability level of other units stayed below 3% except for ozone contact tank (OCT, 13.5%) and activated carbon filtration tank (ACFT, 34.39%). It meant that filtration processes promoted the increase in cultivability of suspended bacteria remarkably, which indicated biodegrading capability. In the unit of OCT, microbial diversity indexes declined drastically, and the dominant bacteria were affiliated to Proteobacteria phylum (99.9%) and Betaproteobacteria class (86.3%), which were also the dominant bacteria in the effluent of other units. Besides, the primary genus was Limnohabitans in the effluents of SFT (17.4%) as well as ACFT (25.6%), which was inferred to be the crucial contributors for the biodegradable function in the filtration units. Overall, this paper provided an overview of community composition of each processing units in a DWTP as well as reference for better developing microbial function for drinking water treatment in the future.

  20. Growth of juvenile blue mussels (Mytilus edulis) on suspended collectors in the Dutch Wadden Sea

    NARCIS (Netherlands)

    Jacobs, P.; Beauchemin, C.; Riegman, R.

    2014-01-01

    In The Netherlands, fishing for juvenile blue mussels (Mytilus edulis) on wild beds is gradually replaced by harvesting of seeds from suspended collectors. Both the relaxation of fishing as well as the up-scaling of the number of seed collectors are expected to result in an increase in the number of