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Sample records for advanced colloids experiment

  1. Advanced Colloids Experiment (ACE-T1)

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ron; Brown, Dan; Eustace, John

    2015-01-01

    Increment 45 - 46 Science Symposium presentation of Advanced Colloids Experiment (ACE-T1) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  2. Advanced Colloids Experiment (ACE-H-2)

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ron; Chmiel, Alan J.; Eustace, John; LaBarbera, Melissa

    2015-01-01

    Increment 43 - 44 Science Symposium presentation of Advanced Colloids Experiment (ACE-H-2) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  3. Advanced Colloids Experiment (ACE) Science Overview

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ronald J.; Chiaramonte, Francis P.; Luna, Unique J.; Chaiken, Paul M.; Hollingsworth, Andrew; Secanna, Stefano; Weitz, David; Lu, Peter; Yodh, Arjun; Yunker, Peter; Lohr, Matthew; Gratale, Matthew; Lynch, Matthew; Kodger, Thomas; Piazza, Roberto; Buzzaccaro, Stefano; Cipelletti, Luca; Schall, Peter; Veen, Sandra; Wegdam, Gerhard; Lee, Chand-Soo; Choi, Chang-Hyung; Paul, Anna-Lisa; Ferl, Robert J.; Cohen, Jacob

    2013-01-01

    The Advanced Colloids Experiment is being conducted on the International Space Station (ISS) using the Light Microscopy Module (LMM) in the Fluids Integrated Rack (FIR). Work to date will be discussed and future plans and opportunities will be highlighted. The LMM is a microscope facility designed to allow scientists to process, manipulate, and characterize colloidal samples in micro-gravity where the absence of gravitational settling and particle jamming enables scientists to study such things as:a.The role that disordered and ordered-packing of spheres play in the phase diagram and equation of state of hard sphere systems,b.crystal nucleation and growth, growth instabilities, and the glass transition, c.gelation and phase separation of colloid polymer mixtures,d.crystallization of colloidal binary alloys,e.competition between crystallization and phase separation,f.effects of anisotropy and specific interactions on packing, aggregation, frustration and crystallization,g.effects of specific reversible and irreversible interactions mediated in the first case by hybridization of complementary DNA strands attached to separate colloidal particles,h.Lock and key interactions between colloids with dimples and spheres which match the size and shape of the dimples,i.finding the phase diagrams of isotropic and interacting particles,j.new techniques for complex self-assembly including scenarios for self-replication, k.critical Casimir forces,l.biology (real and model systems) in microgravity,m.etc. By adding additional microscopy capabilities to the existing LMM, NASA will increase the tools available for scientists that fly experiments on the ISS enabling scientists to observe directly what is happening at the particle level. Presently, theories are needed to bridge the gap between what is being observed (at a macroscopic level when photographing samples) with what is happening at a particle (or microscopic) level. What is happening at a microscopic level will be directly

  4. Advancing colloidal quantum dot photovoltaic technology

    NASA Astrophysics Data System (ADS)

    Cheng, Yan; Arinze, Ebuka S.; Palmquist, Nathan; Thon, Susanna M.

    2016-06-01

    Colloidal quantum dots (CQDs) are attractive materials for solar cells due to their low cost, ease of fabrication and spectral tunability. Progress in CQD photovoltaic technology over the past decade has resulted in power conversion efficiencies approaching 10%. In this review, we give an overview of this progress, and discuss limiting mechanisms and paths for future improvement in CQD solar cell technology.We briefly summarize nanoparticle synthesis and film processing methods and evaluate the optoelectronic properties of CQD films, including the crucial role that surface ligands play in materials performance. We give an overview of device architecture engineering in CQD solar cells. The compromise between carrier extraction and photon absorption in CQD photovoltaics is analyzed along with different strategies for overcoming this trade-off. We then focus on recent advances in absorption enhancement through innovative device design and the use of nanophotonics. Several light-trapping schemes, which have resulted in large increases in cell photocurrent, are described in detail. In particular, integrating plasmonic elements into CQD devices has emerged as a promising approach to enhance photon absorption through both near-field coupling and far-field scattering effects. We also discuss strategies for overcoming the single junction efficiency limits in CQD solar cells, including tandem architectures, multiple exciton generation and hybrid materials schemes. Finally, we offer a perspective on future directions for the field and the most promising paths for achieving higher device efficiencies.

  5. Recent Advances in Colloidal and Interfacial Phenomena Involving Liquid Crystals

    PubMed Central

    Bai, Yiqun; Abbott, Nicholas L.

    2011-01-01

    -dependent ordering (particularly in the context of LC emulsion droplets). The third and final advance addressed in this article involves interactions between colloids mediated by LCs. Recent experiments involving microparticles deposited at the LC-aqueous interface have revealed that LC-mediated interactions can drive interfacial assemblies of particles through reversible ordering transitions (e.g., from one-dimensional chains to two-dimensional arrays with local hexagonal symmetry). In addition, recent single nanoparticle measurements suggest that the ordering of LCs about nanoparticles differs substantially from micrometer-sized particles and that the interactions between nanoparticles mediated by the LCs are far weaker than predicted by theory (sufficiently weak that the interactions are reversible and thus enable self-assembly). Finally, LC-mediated interactions between colloidal particles have also been shown to lead to the formation of colloid-in-LC gels that possess mechanical properties relevant to the design of materials to interface with living biological systems. Overall, these three topics serve to illustrate the broad opportunities that exist to do fundamental interfacial science and discovery-oriented research involving LCs. PMID:21090596

  6. A Simple Experiment Illustrating the Structure of Association Colloids.

    ERIC Educational Resources Information Center

    Friberg, Stig. E.; Bendiksen, Beverly

    1979-01-01

    The experiment described is intended to illustrate the intermolecular phenomena involved in association colloids. These are normal and inverse micelles and lyotropic liquid crystals. Solubilization, microemulsion and emulsion are discussed. (Author/SA)

  7. Advanced rheological characterization of soft colloidal model systems

    NASA Astrophysics Data System (ADS)

    Gupta, S.; Kundu, S. K.; Stellbrink, J.; Willner, L.; Allgaier, J.; Richter, D.

    2012-11-01

    The complex flow behavior of polymer-based soft colloidal model systems was investigated using steady and oscillatory shear to prove new concepts for advanced rheological characterization. In the very dilute regime we investigated high molecular weight polybutadiene star polymers to quantify the internal relaxation time arising from the polymeric nature of these ultra-soft colloids. The observed shear-induced brush deformation is interpreted in terms of the internal Zimm time τz. The observed dependence of τz on matrix viscosity can be explained by shrinkage of the star polymer due to an increasing incompatibility with increasing matrix molecular weight. The influence of the polymeric nature on the characteristic structural relaxation time in the concentrated regime was investigated using non-linear rheology following Wyss et al (SRFS) (2007 Phys. Rev. Lett. 98 238303). Here we used star-like block copolymer micelles to systematically tune the ‘softness’ of the colloids by variation of the block ratio. A master curve with proper scaling parameters could be generated independent of the degree of colloidal ‘softness’. However, the obtained strain-rate independent structural relaxation time τ0 was not observed in the linear regime. In addition, a high frequency discrepancy was clearly found in all our experimental data. Both reflect the shortcomings of the SRFS approach.

  8. Humic colloid-borne natural polyvalent metal ions: dissociation experiment.

    PubMed

    Geckeis, H; Rabung, Th; Ngo Manh, T; Kim, J I; Beck, H P

    2002-07-01

    The natural association nature of the humic colloid-borne trace elements is investigated. Rare earth elements (REE) Th and U are chosen as naturally occurring representatives and chemical homologues for actinides of different oxidation states present in nuclear waste. Tri- and tetravalent elements in two investigated Gorleben groundwaters (Gohy-532 and -2227) almost exclusively occur as humic or fulvic colloid-borne species. Their desorption behavior from colloids is examined in the unperturbed groundwater (pH approximately 8) under anaerobic conditions (Ar/1% CO2) by addition of a chelating cation exchanger resin. Particularly, the dissociation process of naturally occurring Eu(III) in the groundwater is compared with the Eu(III) desorption from its humate complex prepared with purified Aldrich humic acid in a buffered aqueous solution at pH approximately 8. The Eu(III) dissociation from the groundwater colloids is found to be considerably slower than found for the humate complex synthesized in the laboratory. This suggests that under natural aquatic conditions the Eu(III) binding in colloids is chemically different from the simple humate complexation as observed in the laboratory experiment. The colloid characterization bythe size exclusion chromatography (SEC) and the flow field-flow fractionation (FFFF) indicates that natural colloid-borne trace elements are found predominantly in colloids of larger size (>15 nm in size), while Eu(III) in its humate complex is found mainly in colloids of hydrodynamic diameters <5 nm. The slower desorption kinetics and the larger colloid size suggest that the polyvalent metal ion binding in natural humic colloids is associated to polynucleation with other co-present trace metal ions. Radiotracer experiments reveal that isotopic equilibria with the naturally colloid-borne trace elements are not attained within a period of more than 100 days, indicating irreversible binding of at least a part of colloid-borne polyvalent trace

  9. COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FIELD EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (EPA/600/S-99/001)

    EPA Science Inventory

    The major hypothesis driving this research, that the transport of colloids in a contaminant plume is limited by the advance of the chemical agent causing colloid mobilization, was tested by (1) examining the dependence of colloid transport and mobilization on chemical perturbatio...

  10. Switching light with light - advanced functional colloidal monolayers

    NASA Astrophysics Data System (ADS)

    Bley, K.; Sinatra, N.; Vogel, N.; Landfester, K.; Weiss, C. K.

    2013-12-01

    Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica colloids are assembled into monolayers. However, the incorporation of functional molecules into such colloids offers a convenient possibility of implementing additional properties to the two-dimensional crystal. Here, we present the formation of novel functional colloidal monolayers with photoswitchable fluorescence. The miniemulsion polymerization technique was used to incorporate an appropriate dye system of a perylene-based fluorophore and a bis-arylethene as a photochrome in polymeric colloids in defined ratios. Upon irradiation with UV or visible light the photochrome reversibly isomerizes from the ring-closed form, which is able to absorb light of the emission wavelength of the fluorescent dye and the ring-open form, which is not. The fluorescence emission of the dye can thus be reversibly switched on and off with light even when embedded in colloids. The colloids were self-assembled at the air-water interface to produce hexagonally ordered functional monolayers and more complex binary crystals. We investigate in detail the influence of the polymeric matrix on the switching properties of the fluorophore/photochrome system and find that the rate constants for the photoswitching, which all lie in the same range, are less influenced by the polymeric environment than expected. We demonstrate the reversible switching of the fluorescence emission in self-assembled colloidal monolayers. The arrangement of broadly distributed functional colloids into ordered monolayers with high addressability was obtained by the formation of binary colloidal monolayers.Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica

  11. Switching light with light - advanced functional colloidal monolayers

    NASA Astrophysics Data System (ADS)

    Bley, K.; Sinatra, N.; Vogel, N.; Landfester, K.; Weiss, C. K.

    2013-12-01

    Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica colloids are assembled into monolayers. However, the incorporation of functional molecules into such colloids offers a convenient possibility of implementing additional properties to the two-dimensional crystal. Here, we present the formation of novel functional colloidal monolayers with photoswitchable fluorescence. The miniemulsion polymerization technique was used to incorporate an appropriate dye system of a perylene-based fluorophore and a bis-arylethene as a photochrome in polymeric colloids in defined ratios. Upon irradiation with UV or visible light the photochrome reversibly isomerizes from the ring-closed form, which is able to absorb light of the emission wavelength of the fluorescent dye and the ring-open form, which is not. The fluorescence emission of the dye can thus be reversibly switched on and off with light even when embedded in colloids. The colloids were self-assembled at the air-water interface to produce hexagonally ordered functional monolayers and more complex binary crystals. We investigate in detail the influence of the polymeric matrix on the switching properties of the fluorophore/photochrome system and find that the rate constants for the photoswitching, which all lie in the same range, are less influenced by the polymeric environment than expected. We demonstrate the reversible switching of the fluorescence emission in self-assembled colloidal monolayers. The arrangement of broadly distributed functional colloids into ordered monolayers with high addressability was obtained by the formation of binary colloidal monolayers.Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica

  12. Advanced Doppler tracking experiments

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.

    1989-01-01

    The Doppler tracking method is currently the only technique available for broadband gravitational wave searches in the approx. 10(exp -4) to 10(exp -1) Hz low frequency band. A brief review is given of the Doppler method, a discussion of the main noise sources, and a review of experience with current spacecraft and the prospects for sensitivity improvements in an advanced Doppler tracking experiment.

  13. Switching light with light--advanced functional colloidal monolayers.

    PubMed

    Bley, K; Sinatra, N; Vogel, N; Landfester, K; Weiss, C K

    2014-01-01

    Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica colloids are assembled into monolayers. However, the incorporation of functional molecules into such colloids offers a convenient possibility of implementing additional properties to the two-dimensional crystal. Here, we present the formation of novel functional colloidal monolayers with photoswitchable fluorescence. The miniemulsion polymerization technique was used to incorporate an appropriate dye system of a perylene-based fluorophore and a bis-arylethene as a photochrome in polymeric colloids in defined ratios. Upon irradiation with UV or visible light the photochrome reversibly isomerizes from the ring-closed form, which is able to absorb light of the emission wavelength of the fluorescent dye and the ring-open form, which is not. The fluorescence emission of the dye can thus be reversibly switched on and off with light even when embedded in colloids. The colloids were self-assembled at the air-water interface to produce hexagonally ordered functional monolayers and more complex binary crystals. We investigate in detail the influence of the polymeric matrix on the switching properties of the fluorophore/photochrome system and find that the rate constants for the photoswitching, which all lie in the same range, are less influenced by the polymeric environment than expected. We demonstrate the reversible switching of the fluorescence emission in self-assembled colloidal monolayers. The arrangement of broadly distributed functional colloids into ordered monolayers with high addressability was obtained by the formation of binary colloidal monolayers. PMID:24227011

  14. Results From the Physics of Colloids Experiment on ISS

    NASA Technical Reports Server (NTRS)

    Weitz, David; Bailey, Arthur; Manley, Suliana; Prasad, Vikram; Christianson, Rebecca; Sankaran, Subramanian; Doherty, Michael; Jankovsky, Amy; Lorik, Tibor; Shiley, William

    2002-01-01

    The Physics of Colloids in Space (PCS) experiment was accommodated within International Space Station (ISS) EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Rack 2 and was remotely operated from early June 2001 until February 2002 from NASA Glenn Research Center's Telescience Support Center (TSC) in Cleveland, Ohio, and from the remote site at Harvard University in Cambridge, Massachusetts. PCS was launched on 4/19/2001 on Space Shuttle STS-100. The experiment was activated on 5/31/2001. The entire experimental setup performed remarkably well, and accomplished 2400 hours of science operations on-orbit. The sophisticated instrumentation in PCS is capable of dynamic and static light scattering from 11 to 169 degrees, Bragg scattering over the range from 10 to 60 degrees, dynamic and static light scattering at low angles from 0.3 to 6.0 degrees, and color imaging. The long duration microgravity environment on the ISS facilitated extended studies on the growth and coarsening characteristics of binary crystals. The de-mixing of the colloid-polymer critical-point sample was also studied as it phase-separated into two phases. Further, aging studies on a col-pol gel, gelation rate studies in extremely low concentration fractal gels over several days, and studies on a glass sample, all provided valuable information. Several exciting and unique aspects of these results are discussed here.

  15. Advanced Liquid Feed Experiment

    NASA Astrophysics Data System (ADS)

    Distefano, E.; Noll, C.

    1993-06-01

    The Advanced Liquid Feed Experiment (ALFE) is a Hitchhiker experiment flown on board the Shuttle of STS-39 as part of the Space Test Payload-1 (STP-1). The purpose of ALFE is to evaluate new propellant management components and operations under the low gravity flight environment of the Space Shuttle for eventual use in an advanced spacecraft feed system. These components and operations include an electronic pressure regulator, an ultrasonic flowmeter, an ultrasonic point sensor gage, and on-orbit refill of an auxiliary propellant tank. The tests are performed with two transparent tanks with dyed Freon 113, observed by a camera and controlled by ground commands and an on-board computer. Results show that the electronic pressure regulator provides smooth pressure ramp-up, sustained pressure control, and the flexibility to change pressure settings in flight. The ultrasonic flowmeter accurately measures flow and detects gas ingestion. The ultrasonic point sensors function well in space, but not as a gage during sustained low-gravity conditions, as they, like other point gages, are subject to the uncertainties of propellant geometry in a given tank. Propellant transfer operations can be performed with liquid-free ullage equalization at a 20 percent fill level, gas-free liquid transfer from 20-65 percent fill level, minimal slosh, and can be automated.

  16. Recent Advances in the Theory and Simulation of Model Colloidal Microphase Formers.

    PubMed

    Zhuang, Yuan; Charbonneau, Patrick

    2016-08-18

    This mini-review synthesizes our understanding of the equilibrium behavior of particle-based models with short-range attractive and long-range repulsive (SALR) interactions. These models, which can form stable periodic microphases, aim to reproduce the essence of colloidal suspensions with competing interparticle interactions. Ordered structures, however, have yet to be obtained in experiments. In order to better understand the hurdles to periodic microphase assembly, marked theoretical and simulation advances have been made over the past few years. Here, we present recent progress in the study of microphases in models with SALR interactions using liquid-state theory and density-functional theory as well as numerical simulations. Combining these various approaches provides a description of periodic microphases, and gives insights into the rich phenomenology of the surrounding disordered regime. Ongoing research directions in the thermodynamics of models with SALR interactions are also presented. PMID:27466702

  17. Characterization and Application of Colloidal Nanocrystalline Materials for Advanced Photovoltaics

    NASA Astrophysics Data System (ADS)

    Bhandari, Khagendra P.

    Solar energy is Earth's primary source of renewable energy and photovoltaic solar cells enable the direct conversion of sunlight into electricity. Crystalline silicon solar cells and modules have dominated photovoltaic technology from the beginning and they now constitute more than 90% of the PV market. Thin film (CdTe and CIGS) solar cells and modules come in second position in market share. Some organic, dye-sensitized and perovskite solar cells are emerging in the market but are not yet in full commercial scale. Solar cells made from colloidal nanocrystalline materials may eventually provide both low cost and high efficiency because of their promising properties such as high absorption coefficient, size tunable band gap, and quantum confinement effect. It is also expected that the greenhouse gas emission and energy payback time from nanocrystalline solar PV systems will also be least compared to all other types of PV systems mainly due to the least embodied energy throughout their life time. The two well-known junction architectures for the fabrication of quantum dot based photovoltaic devices are the Schottky junction and heterojunction. In Schottky junction cells, a heteropartner semiconducting material is not required. A low work function metal is used as the back contact, a transparent conducting layer is used as the front contact, and the layer of electronically-coupled quantum dots is placed between these two materials. Schottky junction solar cells explain the usefulness of nanocrystalline materials for high efficiency heterojunction solar cells. For heterojunction devices, n-type semiconducting materials such as ZnO , CdS or TiO2 have been used as suitable heteropartners. Here, PbS quantum dot solar cells were fabricated using ZnO and CdS semiconductor films as window layers. Both of the heteropartners are sputter-deposited onto TCO coated glass substrates; ZnO was deposited with the substrate held at room temperature and for CdS the substrate was at 250

  18. Movie of phase separation during physics of colloids in space experiment

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Still photographs taken over 16 hours on Nov. 13, 2001, on the International Space Station have been condensed into a few seconds to show the de-mixing -- or phase separation -- process studied by the Experiment on Physics of Colloids in Space. Commanded from the ground, dozens of similar tests have been conducted since the experiment arrived on ISS in 2000. The sample is a mix of polymethylmethacrylate (PMMA or acrylic) colloids, polystyrene polymers and solvents. The circular area in the video is 2 cm (0.8 in.) in diameter. The phase separation process occurs spontaneously after the sample is mechanically mixed. The evolving lighter regions are rich in colloid and have the structure of a liquid. The dark regions are poor in colloids and have the structure of a gas. This behavior carnot be observed on Earth because gravity causes the particles to fall out of solution faster than the phase separation can occur. While similar to a gas-liquid phase transition, the growth rate observed in this test is different from any atomic gas-liquid or liquid-liquid phase transition ever measured experimentally. Ultimately, the sample separates into colloid-poor and colloid-rich areas, just as oil and vinegar separate. The fundamental science of de-mixing in this colloid-polymer sample is the same found in the annealing of metal alloys and plastic polymer blends. Improving the understanding of this process may lead to improving processing of these materials on Earth.

  19. Phase separation during the Experiment on Physics of Colloids in Space

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Still photographs taken over 16 hours on Nov. 13, 2001, on the International Space Station have been condensed into a few seconds to show the de-mixing -- or phase separation -- process studied by the Experiment on Physics of Colloids in Space. Commanded from the ground, dozens of similar tests have been conducted since the experiment arrived on ISS in 2000. The sample is a mix of polymethylmethacrylate (PMMA or acrylic) colloids, polystyrene polymers and solvents. The circular area is 2 cm (0.8 in.) in diameter. The phase separation process occurs spontaneously after the sample is mechanically mixed. The evolving lighter regions are rich in colloid and have the structure of a liquid. The dark regions are poor in colloids and have the structure of a gas. This behavior carnot be observed on Earth because gravity causes the particles to fall out of solution faster than the phase separation can occur. While similar to a gas-liquid phase transition, the growth rate observed in this test is different from any atomic gas-liquid or liquid-liquid phase transition ever measured experimentally. Ultimately, the sample separates into colloid-poor and colloid-rich areas, just as oil and vinegar separate. The fundamental science of de-mixing in this colloid-polymer sample is the same found in the annealing of metal alloys and plastic polymer blends. Improving the understanding of this process may lead to improving processing of these materials on Earth.

  20. Physics of Colloids in Space--Plus (PCS+) Experiment Completed Flight Acceptance Testing

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.

    2004-01-01

    The Physics of Colloids in Space--Plus (PCS+) experiment successfully completed system-level flight acceptance testing in the fall of 2003. This testing included electromagnetic interference (EMI) testing, vibration testing, and thermal testing. PCS+, an Expedite the Process of Experiments to Space Station (EXPRESS) Rack payload will deploy a second set of colloid samples within the PCS flight hardware system that flew on the International Space Station (ISS) from April 2001 to June 2002. PCS+ is slated to return to the ISS in late 2004 or early 2005.

  1. Advanced antireflective nanostructures etched down from nanosilver colloid-transformed island mask

    NASA Astrophysics Data System (ADS)

    Park, Seong-Je; Kim, Chul-Hyun; Lee, Ji-Hye; Jeong, Jun-Ho; Lee, Eung-Sug; Choi, Jun-Hyuk

    2012-11-01

    Advanced fabrication methods for antireflective nanostructures are presented via the formation of thermally grown nanosilver islands from continuously deposited colloidal multilayers, followed by a multi-step reactive ion etch (RIE) with optimized gas mixture rate. This process allows the formation of a random array of nanostructures of diameter 150 nm or less and height greater than 200 nm. The reflectance falls to around 0.7% in the visible region, with reasonably enhanced broadband stability and reduced incidence angle dependence. The tunability of antireflection was investigated with respect to several parameters associated with the nanosilver etch mask fabrication and RIE conditions.

  2. Ellipsoids beat Spheres: Experiments with Candies, Colloids and Crystals

    NASA Astrophysics Data System (ADS)

    Chaikin, Paul

    2006-04-01

    How many gumballs fit in the glass sphere of a gumball machine? Scientists have been puzzling over problems like this since the Ancient Greeks. Yet it was only recently proven that the standard way of stacking oranges at a grocery store--with one orange on top of each set of three below--is the densist packing for spheres, with a packing fraction φ˜ 0.74. Random (amorphous) packings of spheres have a lower density, with φ ˜0.64. The density of crystalline and random packings of atoms is intimately related to the melting transition in matter. We have studied the crystal-liquid transition in spherical colloidal systems on earth and in microgravity. The simplest objects to study after spheres are squashed spheres -- ellipsoids. Surprisingly we find that ellipsoids can randomly pack more densely than spheres, up to φ˜0.68 - 0.71 for a shape close to that of M&M's^ Candies, and even approach φ˜0.75 for general ellipsoids. The higher density relates directly to the higher number of neighbors needed to prevent the more asymetric ellipsoid from rotating. We have also found the ellipsoids can be packed in a crystalline array to a density, φ˜.7707 which exceeds the highest previous packing. Our findings provide insights into granular materials, rigidity, crystals and glasses, and they may lead to higher quality ceramic materials.

  3. Celebrating Soft Matter's 10th anniversary: Testing the foundations of classical entropy: colloid experiments.

    PubMed

    Cates, Michael E; Manoharan, Vinothan N

    2015-09-01

    Defining the entropy of classical particles raises a number of paradoxes and ambiguities, some of which have been known for over a century. Several, such as Gibbs' paradox, involve the fact that classical particles are distinguishable, and in textbooks these are often 'resolved' by appeal to the quantum-mechanical indistinguishability of atoms or molecules of the same type. However, questions then remain of how to correctly define the entropy of large poly-atomic particles such as colloids in suspension, of which no two are exactly alike. By performing experiments on such colloids, one can establish that certain definitions of the classical entropy fit the data, while others in the literature do not. Specifically, the experimental facts point firmly to an 'informatic' interpretation that dates back to Gibbs: entropy is determined by the number of microstates that we as observers choose to treat as equivalent when we identify a macrostate. This approach, unlike some others, can account for the existence of colloidal crystals, and for the observed abundances of colloidal clusters of different shapes. We also address some lesser-known paradoxes whereby the physics of colloidal assemblies, which ought to be purely classical, seems to involve quantum mechanics directly. The experimental symptoms of such involvement are predicted to be 'isotope effects' in which colloids with different inertial masses, but otherwise identical sizes and properties, show different aggregation statistics. These paradoxes are caused by focussing one's attention on some classical degrees while neglecting others; when all are treated equally, all isotope effects are found to vanish. PMID:26235667

  4. Physics of Colloids in Space: Microgravity Experiment Launched, Installed, and Activated on the International Space Station

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.

    2002-01-01

    The Physics of Colloids in Space (PCS) experiment is a Microgravity Fluids Physics investigation that is presently located in an Expedite the Process of Experiments to Space Station (EXPRESS) Rack on the International Space Station. PCS was launched to the International Space Station on April 19, 2001, activated on May 31, 2001, and will continue to operate about 90 hr per week through May 2002.

  5. Advances in colloid and biocolloid transport in porous media: particle size-dependent dispersivity and gravity effects

    NASA Astrophysics Data System (ADS)

    Chrysikopoulos, Constantinos V.; Manariotis, Ioannis D.; Syngouna, Vasiliki I.

    2014-05-01

    Accurate prediction of colloid and biocolloid transport in porous media relies heavily on usage of suitable dispersion coefficients. The widespread procedure for dispersion coefficient determination consists of conducting conservative tracer experiments and subsequently fitting the collected breakthrough data with a selected advection-dispersion transport model. The fitted dispersion coefficient is assumed to characterize the porous medium and is often used thereafter to analyze experimental results obtained from the same porous medium with other solutes, colloids, and biocolloids. The classical advection-dispersion equation implies that Fick's first law of diffusion adequately describes the dispersion process, or that the dispersive flux is proportional to the concentration gradient. Therefore, the above-described procedure inherently assumes that the dispersive flux of all solutes, colloids and biocolloids under the same flow field conditions is exactly the same. Furthermore, the available mathematical models for colloid and biocoloid transport in porous media do not adequately account for gravity effects. Here an extensive laboratory study was undertaken in order to assess whether the dispersivity, which traditionally has been considered to be a property of the porous medium, is dependent on colloid particle size, interstitial velocity and length scale. The breakthrough curves were successfully simulated with a mathematical model describing colloid and biocolloid transport in homogeneous, water saturated porous media. The results demonstrated that the dispersivity increases very slowly with increasing interstitial velocity, and increases with column length. Furthermore, contrary to earlier results, which were based either on just a few experimental observations or experimental conditions leading to low mass recoveries, dispersivity was positively correlated with colloid particle size. Also, transport experiments were performed with biocolloids (bacteriophages:

  6. Colloid Facilitated Transport of Radioactive Cations in the Vadose Zone: Field Experiments Oak Ridge

    SciTech Connect

    James E. Saiers

    2012-09-20

    The overarching goal of this study was to improve understanding of colloid-facilitated transport of radioactive cations through unsaturated soils and sediments. We conducted a suite of laboratory experiments and field experiments on the vadose-zone transport of colloids, organic matter, and associated contaminants of interest to the U.S. Department of Energy (DOE). The laboratory and field experiments, together with transport modeling, were designed to accomplish the following detailed objectives: 1. Evaluation of the relative importance of inorganic colloids and organic matter to the facilitation of radioactive cation transport in the vadose zone; 2. Assessment of the role of adsorption and desorption kinetics in the facilitated transport of radioactive cations in the vadose zone; 3. Examination of the effects of rainfall and infiltration dynamics and in the facilitated transport of radioactive cations through the vadose zone; 4. Exploration of the role of soil heterogeneity and preferential flow paths (e.g., macropores) on the facilitated transport of radioactive cations in the vadose zone; 5. Development of a mathematical model of facilitated transport of contaminants in the vadose zone that accurately incorporates pore-scale and column-scale processes with the practicality of predicting transport with readily available parameters.

  7. Physics of Colloids in Space (PCS): Microgravity Experiment Completed Operations on the International Space Station

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.; Sankaran, Subramanian

    2003-01-01

    Immediately after mixing, the two-phase-like colloid-polymer critical point sample begins to phase separate, or de-mix, into two phases-one that resembles a gas and one that resembles a liquid, except that the particles are colloids and not atoms. The colloid-poor black regions (colloidal gas) grow bigger, and the colloid-rich white regions (colloidal liquid) become whiter as the domains further coarsen. Finally, complete phase separation is achieved, that is, just one region of each colloid-rich (white) and colloid-poor (black) phase. This process was studied over four decades of length scale, from 1 micrometer to 1 centimeter.

  8. Physics of Hard Sphere Experiment: Scattering, Rheology and Microscopy Study of Colloidal Particles

    NASA Technical Reports Server (NTRS)

    Cheng, Z.-D.; Zhu, J.; Phan, S.-E.; Russel, W. B.; Chaikin, P. M.; Meyer, W. V.

    2002-01-01

    The Physics of Hard Sphere Experiment has two incarnations: the first as a scattering and rheology experiment on STS-83 and STS-94 and the second as a microscopy experiment to be performed in the future on LMM on the space station. Here we describe some of the quantitative and qualitative results from previous flights on the dynamics of crystallization in microgravity and especially the observed interaction of growing crystallites in the coexistance regime. To clarify rheological measurements we also present ground based experiments on the low shear rate viscosity and diffusion coefficient of several hard sphere experiments at high volume fraction. We also show how these experiments will be performed with confocal microscopy and laser tweezers in our lab and as preparation for the phAse II experiments on LMM. One of the main aims of the microscopy study will be the control of colloidal samples using an array of applied fields with an eye toward colloidal architectures. Temperature gradients, electric field gradients, laser tweezers and a variety of switchable imposed surface patterns are used toward this control.

  9. Colloidal Disorder-Order Transition Experiment Probes Particle Interactions in Microgravity

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Everything in the universe is made up of the same basic building blocks - atoms. All physical properties of matter such as weight, hardness, and color are determined by the kind of atoms present and the way they interact with each other. The Colloidal Disorder-Order Transition (CDOT) shuttle flight experiment tested fundamental theories that model atomic interactions. The experiment was part of the Second United States Microgravity Laboratory (USML-2) aboard the Space Shuttle Columbia, which flew from October 20 to November 5, 1995.

  10. Colloidal Asphaltene Deposition and Aggregation in Capillary Flow: Experiments and Mesoscopic Simulation

    NASA Astrophysics Data System (ADS)

    Boek, Edo S.; Ladva, Hemant K.; Crawshaw, John P.; Padding, Johan T.

    2008-07-01

    The aggregation and deposition of colloidal asphaltene in reservoir rock is a significant problem in the oil industry. To obtain a fundamental understanding of this phenomenon, we have studied the deposition and aggregation of colloidal asphaltene in capillary flow by experiment and simulation. For the simulation, we have used the stochastic rotation dynamics (SRD) method, in which the solvent hydrodynamic emerges from the collisions between the solvent particles, while the Brownian motion emerges naturally from the interactions between the colloidal asphaltene particles and the solvent. The asphaltene colloids interact through a screened Coulomb potential. We vary the well depth ɛ∝ and the flow rate v to obtain Peflow≫1 (hydrodynamic interactions dominate) and Re≪1 (Stokes flow). In the simulations, we impose a pressure drop over the capillary length and measure the corresponding solvent flow rate. We observe that the transient solvent flow rate decreases when the asphaltene particles become more "sticky". For a well depth ɛ∝ = 2kBT, a monolayer deposits on the capillary wall. With an increasing well depth, the capillary becomes totally blocked. The clogging is transient for ɛ∝ = 5kBT, but appears to be permanent for ɛ∝ = 10-20 kBT. We compare our simulation results with flow experiments in glass capillaries, where we use extracted asphaltenes in toluene, reprecipitated with n-heptane. In the experiments, the dynamics of asphaltene precipitation and deposition were monitored in a slot capillary using optical microscopy under flow conditions similar to those used in the simulation. Maintaining a constant flow rate of 5 μL min-1, we found that the pressure drop across the capillary first increased slowly, followed by a sharp increase, corresponding to a complete local blockage of the capillary. Doubling the flow rate to 10 μL min-1, we observe that the initial deposition occurs faster but the deposits are subsequently entrained by the flow. We

  11. Observation platform for colloid science experiments using the ISS Light Microscopy Module

    NASA Astrophysics Data System (ADS)

    Kurk, Michael Andy; Todd, Paul; Vellinger, John C.

    2012-07-01

    The role of gravity in colloid self-assembly is a long-standing subject of inquiry. The International Space Station Light Microscopy Module (LMM) is a potentially powerful tool for implementing the observation of colloids in a high-quality low-gravity environment. The main requirements for making observations of colloid self-assembly include a small-volume, thermally stabilized environment, the addition and removal of small volumes of fluids (colloidal suspensions or reagents), and on-demand access to electrokinetic and/or magnetophoretic body forces. A modular device has been designed in which a custom electronics module is designed to mate with the existing LMM cold plate and LMM controlling power. All control features, electrical power, microscope illuminator, fluid pumps and valves are components of this module. This module lies under, mates with and serves an experiment module which houses the fluid containers that fit under the LMM objective lenses and fluid transfer tubing. Four versions of the experiment module have been designed: a hollow-slide stopped flow cell, a multiwell quiescent module, a magnetization module and an electrokinetic module. Interfaces can be established in the viewing field using the stopped-flow cell, which is also applicable to living systems such as microbial cultures, suspended blood cells, nematodes, etc. Multi-well modules can be equipped with in-line static mixers that allow the investigator to combine pairs of fluids or to re-homogenize settled samples. The maximum dimension of all modules is 16 cm, so the modules can be transported in large numbers on cargo or manned spacecraft to the ISS. A doubly-contained transfer tool can be used to transfer fluids in and out of the experiment module, which is equipped with a fluid coupling that mates to the transfer tool. Experiment-specific versions of these modules can be prepared for approved experimenters within a 1-year period. The research for these devices is supported by NASA

  12. Self-assembly of "Mickey Mouse" shaped colloids into tube-like structures: experiments and simulations.

    PubMed

    Wolters, Joost R; Avvisati, Guido; Hagemans, Fabian; Vissers, Teun; Kraft, Daniela J; Dijkstra, Marjolein; Kegel, Willem K

    2015-02-14

    The self-assembly of anisotropic patchy particles with a triangular shape was studied by experiments and computer simulations. The colloidal particles were synthesized in a two-step seeded emulsion polymerization process, and consist of a central smooth lobe connected to two rough lobes at an angle of ∼90°, resembling the shape of a "Mickey Mouse" head. Due to the difference in overlap volume, adding an appropriate depletant induces an attractive interaction between the smooth lobes of the colloids only, while the two rough lobes act as steric constraints. The essentially planar geometry of the Mickey Mouse particles is a first geometric deviation of dumbbell shaped patchy particles. This new geometry enables the formation of one-dimensional tube-like structures rather than spherical, essentially zero-dimensional micelles. At sufficiently strong attractions, we indeed find tube-like structures with the sticky lobes at the core and the non-sticky lobes pointing out as steric constraints that limit the growth to one direction, providing the tubes with a well-defined diameter but variable length both in experiments and simulations. In the simulations, we found that the internal structure of the tubular fragments could either be straight or twisted into so-called Bernal spirals. PMID:25523360

  13. Advanced communications experiments for Spacelab

    NASA Technical Reports Server (NTRS)

    Ehrlich, E.

    1975-01-01

    The Spacelab design and mission capabilities appear to provide a practical vehicle for meeting communication experiment needs. Results of recent discussions and numerous contractual activities have conclusively corroborated the potential useful role that a manned laboratory in space can afford to the communications community. Some examples of the experiments that appear presently as strong candidates for early flights on the Spacelab missions of the 1980s are discussed. Particular attention is given to radio frequency interference, bandwidth compressive modulation, laser experimentation, and use of large deployable communications antenna. It can be expected that the Spacelab will reduce the time, risk, and cost for conducting some communications experiments and developing the related space technology.

  14. LONG-TERM COLLOID MOBILIZATION AND COLLOID-FACILITATED TRANSPORT OF RADIONUCLIDES IN A SEMI-ARID VADOSE ZONE

    SciTech Connect

    Markus Flury; James B. Harsh; Fred Zhang; Glendon W. Gee; Earl D. Mattson; Peter C. L

    2012-08-01

    The main purpose of this project was to improve the fundamental mechanistic understanding and quantification of long-term colloid mobilization and colloid-facilitated transport of radionuclides in the vadose zone, with special emphasis on the semi-arid Hanford site. While we focused some of the experiments on hydrogeological and geochemical conditions of the Hanford site, many of our results apply to colloid and colloid-facilitated transport in general. Specific objectives were (1) to determine the mechanisms of colloid mobilization and colloid-facilitated radionuclide transport in undisturbed Hanford sediments under unsaturated flow, (2) to quantify in situ colloid mobilization and colloid-facilitated radionuclidetransport from Hanford sediments under field conditions, and (3) to develop a field-scale conceptual and numerical model for colloid mobilization and transport at the Hanford vadose zone, and use that model to predict long-term colloid and colloid- facilitated radionuclide transport. To achieve these goals and objectives, we have used a combination of experimental, theoretical, and numerical methods at different spatial scales, ranging from microscopic investigationsof single particle attachment and detachment to larger-scale field experiments using outdoor lysimeters at the Hanford site. Microscopic and single particle investigations provided fundamental insight into mechanisms of colloid interactions with the air-water interface. We could show that a moving air water interface (such as a moving water front during infiltration and drainage) is very effective in removing and mobilizing particles from a stationary surface. We further demonstrated that it is particularly the advancing air-water interface which is mainly responsible for colloid mobilization. Forces acting on the colloids calculated from theory corroborated our experimental results, and confirm that the detachment forces (surface tension forces) during the advancing air-water interface

  15. Hydrodynamics in nanoscale confinement: SFA and colloid probe AFM liquid drainage experiments

    NASA Astrophysics Data System (ADS)

    Krasowska, M.; Popescu, M. N.; Ralston, J.

    2012-12-01

    Flow and drainage of very thin liquid films play an important role in mineral recovery, drop coalescence and emulsion stability, as well as lubrication of micromechanical devices. Studies of liquid flow under strong confinement (i.e., film thickness below a few hundred of nanometers and down to a few nanometers) can reveal the limits of applicability of a classical hydrodynamics description, but are very challenging. The Surface Force Apparatus (SFA) technique has enabled studies of drainage at nanoscale separation between atomically smooth mica sheets. The development of the colloid probe Atomic Force Microscope (AFM) as an alternative technique has allowed a significantly wider variety of confining solid surfaces to be studied. Both the SFA and the colloid probe AFM have been adapted to permit the surfaces confining the film to be soft, e.g., the surface of a drop or bubble, and therefore deformable. We present a succinct review of the experimental and theoretical modeling challenges for such studies and critically discuss the outcomes of recent experiments.

  16. What Is a Colloid?

    ERIC Educational Resources Information Center

    Lamb, William G.

    1985-01-01

    Describes the properties of colloids, listing those commonly encountered (such as whipped cream, mayonnaise, and fog). Also presents several experiments using colloids and discusses "Silly Putty," a colloid with viscoelastic properties whose counterintuitive properties result from its mixture of polymers. (DH)

  17. Organizing a Community Advanced Pharmacy Practice Experience

    PubMed Central

    Koenigsfeld, Carrie Foust; Tice, Angela L

    2006-01-01

    Setting up a community advanced pharmacy practice experience can be an overwhelming task for many pharmacy preceptors. This article provides guidance to pharmacist preceptors in developing a complete and effective community advanced pharmacy practice experience (APPE). When preparing for the APPE, initial discussions with the college or school of pharmacy are key. Benefits, training, and requirements should be addressed. Site preparation, including staff education, will assist in the development process. The preceptor should plan orientation day activities and determine appropriate evaluation and feedback methods. With thorough preparation, the APPE will be rewarding for both the student and the pharmacy site. PMID:17136163

  18. Crystallization of Hard Sphere Colloids in Microgravity: Results of the Colloidal Disorder-Order Transition, CDOT on USML-2. Experiment 33

    NASA Technical Reports Server (NTRS)

    Zhu, Ji-Xiang; Chaikin, P. M.; Li, Min; Russel, W. B.; Ottewill, R. H.; Rogers, R.; Meyer, W. V.

    1998-01-01

    Classical hard spheres have long served as a paradigm for our understanding of the structure of liquids, crystals, and glasses and the transitions between these phases. Ground-based experiments have demonstrated that suspensions of uniform polymer colloids are near-ideal physical realizations of hard spheres. However, gravity appears to play a significant and unexpected role in the formation and structure of these colloidal crystals. In the microgravity environment of the Space Shuttle, crystals grow purely via random stacking of hexagonal close-packed planes, lacking any of the face-centered cubic (FCC) component evident in crystals grown in 1 g beyond melting and allowed some time to settle. Gravity also masks 33-539 the natural growth instabilities of the hard sphere crystals which exhibit striking dendritic arms when grown in microgravity. Finally, high volume fraction "glass" samples which fail to crystallize after more than a year in 1 g begin nucleation after several days and fully crystallize in less than 2 weeks on the Space Shuttle.

  19. Low-cost SWIR sensors: advancing the performance of ROIC-integrated colloidal quantum dot photodiode arrays

    NASA Astrophysics Data System (ADS)

    Klem, Ethan J. D.; Lewis, Jay; Gregory, Chris; Temple, Dorota; Wijewarnasuriya, Priyalal S.; Dhar, Nibir

    2014-06-01

    RTI has developed a novel photodiode technology based on solution-processed PbS colloidal quantum dots (CQD) capable of providing low-cost, high performance detection across the Vis-SWIR spectral range. The most significant advantages of the CQD technology are ease of fabrication, small pixel size, and extended wavelength range. The devices are fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. We will discuss recent advances in device architecture and processing that result in measured dark currents of 15 nA/cm2 at room temperature and enhanced SWIR responsivity from the UV to ~1.7 μm, compare these results to InGaAs detectors, and present measurements of the CQD detectors temperature dependent dark current.

  20. Advanced ISDN satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The research performed by GTE Government Systems and the University of Colorado in support of the NASA Satellite Communications Applications Research (SCAR) Program is summarized. Two levels of research were undertaken. The first dealt with providing interim services Integrated Services Digital Network (ISDN) satellite (ISIS) capabilities that accented basic rate ISDN with a ground control similar to that of the Advanced Communications Technology Satellite (ACTS). The ISIS Network Model development represents satellite systems like the ACTS orbiting switch. The ultimate aim is to move these ACTS ground control functions on-board the next generation of ISDN communications satellite to provide full-service ISDN satellite (FSIS) capabilities. The technical and operational parameters for the advanced ISDN communications satellite design are obtainable from the simulation of ISIS and FSIS engineering software models of the major subsystems of the ISDN communications satellite architecture. Discrete event simulation experiments would generate data for analysis against NASA SCAR performance measure and the data obtained from the ISDN satellite terminal adapter hardware (ISTA) experiments, also developed in the program. The Basic and Option 1 phases of the program are also described and include the following: literature search, traffic mode, network model, scenario specifications, performance measures definitions, hardware experiment design, hardware experiment development, simulator design, and simulator development.

  1. Contact line of adsorbed colloid-polymer droplets in theory and experiment.

    PubMed

    Koning, Jesper; Hennequin, Yves; Bonn, Daniel; Indekeu, Joseph O

    2016-05-01

    The contact line between the colloid-rich bulk liquid and an adsorbed thin film in colloid-polymer mixtures (CPM) is studied by means of an interface displacement model. The interface displacement profiles are compared to laser scanning confocal microscopy (LSCM) images. The mixtures consist of poly(methylmetacrylate) (PMMA) colloids and polystyrene (PS) polymers with polymer-to-colloid size ratio q = 1.18. Based on the experimental parameters, the theoretical model predicts a contact angle for colloid-rich liquid droplets adsorbed on glass of θ∞ = 59°, assuming a contact line with infinite radius, R = ∞. When a contact-line curvature correction and a correction for the protein-limit character of the CPM are taken into account, a modest shift is obtained. The refined theory predicts θ≈ 56°. The contact angle determined visually from the LSCM images is θ≈ 30°. The model predicts a three-phase contact-line tension of τ = -1.2 × 10(-12) N (uncorrected) and τ = -2.3 × 10(-13) N (with protein-limit correction), which is physically sound both in sign and magnitude. The line tension influences the contact angle to a small extent due to the contact line curvature. The predicted width of the transition zone between the thin film and the droplet is about 2 μm. The effect of gravity is noticeable as a deformation near the middle of the droplet. PMID:27029605

  2. The effect of artificial seawater on SERS spectra of amino acids-Ag colloids: an experiment of prebiotic chemistry.

    PubMed

    Nascimento, Fernanda C; Carneiro, Cristine E A; de Santana, Henrique; Zaia, Dimas A M

    2014-01-24

    The large enhancement of signal observed in surface enhanced Raman spectroscopy (SERS) could be helpful for identifying amino acids on the surface of other planets, in particular for Mars, as well as in prebiotic chemistry experiments of interaction minerals/amino acids. This paper reports the effect of several substances (NaCl, MgCl2, KBr, CaSO4, K2SO4, MgSO4, KI, NH4Cl, SrCl2, CaCl2, Na2SO4, KOH, NaOH, H3BO3) on the SERS spectra of colloid of sodium citrate-CSC and colloid of sodium borohydride-CSB. The effect of four different artificial seawaters and these artificial seawaters plus amino acids (α-Ala-alanine, Gly-glycine, Cys-cysteine, AIB-2-aminoisobutiric acid) on SERS spectra using both CSC and CSB was also studied. For CSC, the effect of water, after dilution of the colloid, was the appearance of several absorption bands belonging to sodium citrate in the SERS spectrum. In general, artificial seawaters enhanced several bands in SERS spectra using CSC and CSB and CSC was more sensitive to those artificial seawaters than CSB. The identification of Gly, α-Ala and AIB using CSC or CSB was not possible because several bands belonging to artificial seawaters, sodium citrate or sodium borohydride were enhanced. On the other hand, artificial seawaters did not interfere in the SERS spectra of Cys using CSC or CSB, although the interaction of Cys with each colloid was different. For CSC the band at 2568 cm(-1) (S-H stretching) of Cys vanished and for CSB the intensity of this band decreased, indicating the -SH of Cys was bonded to Ag to form -S-Ag. Thus SERS spectroscopy could be used for Cys detection on Mars soils using Mars land rovers as well as to study the interaction between Cys and minerals in prebiotic chemistry experiments. PMID:24051298

  3. Saturated Zone Colloid Transport

    SciTech Connect

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant retardation

  4. Colloid-Facilitated Transport of 137Cs in Fracture-Fill Material. Experiments and Modeling

    SciTech Connect

    Dittrich, Timothy M.; Reimus, Paul William

    2015-10-29

    In this study, we demonstrate how a combination of batch sorption/desorption experiments and column transport experiments were used to effectively parameterize a model describing the colloid-facilitated transport of Cs in the Grimsel granodiorite/FFM system. Cs partition coefficient estimates onto both the colloids and the stationary media obtained from the batch experiments were used as initial estimates of partition coefficients in the column experiments, and then the column experiment results were used to obtain refined estimates of the number of different sorption sites and the adsorption and desorption rate constants of the sites. The desorption portion of the column breakthrough curves highlighted the importance of accounting for adsorption-desorption hysteresis (or a very nonlinear adsorption isotherm) of the Cs on the FFM in the model, and this portion of the breakthrough curves also dictated that there be at least two different types of sorption sites on the FFM. In the end, the two-site model parameters estimated from the column experiments provided excellent matches to the batch adsorption/desorption data, which provided a measure of assurance in the validity of the model.

  5. Challenges in Teaching "Colloid and Surface Chemistry"--A Danish Experience

    ERIC Educational Resources Information Center

    Kontogeorgis, Georgios M.; Vigild, Martin E.

    2009-01-01

    Seven years ago we were asked, as one of our first teaching duties at the Technical University of Denmark (DTU), to teach a 5 ECTS point course on "Colloid and Surface Chemistry". The topic is itself at the same time exciting and demanding, largely due to its multidisciplinary nature. Several "local" requirements posed additional challenges. The…

  6. Ring around the colloid

    NASA Astrophysics Data System (ADS)

    Cavallaro, Marcello, Jr.; Gharbi, Mohamed A.; Beller, Daniel A.; Čopar, Simon; Shi, Zheng; Kamien, Randall D.; Yang, Shu; Baumgart, Tobias; Stebe, Kathleen J.

    In this work, we show that Janus washers, genus-one colloids with hybrid anchoring conditions, form topologically required defects in nematic liquid crystals. Experiments under crossed polarizers reveal the defect structure to be a rigid disclination loop confined within the colloid, with an accompanying defect in the liquid crystal. When confined to a homeotropic cell, the resulting colloid-defect ring pair tilts relative to the far field director, in contrast to the behavior of toroidal colloids with purely homeotropic anchoring. We show that this tilting behavior can be reversibly suppressed by the introduction of a spherical colloid into the center of the toroid, creating a new kind of multi-shape colloidal assemblage.

  7. Utilizing advanced polymerization techniques for simplifying polymer grafting from silica colloidal crystal substrates

    NASA Astrophysics Data System (ADS)

    Yerneni, Charu K.

    polyacrylamide of varying thickness can be produced by varying the reaction time. Linear polymerization kinetics was studied using IR spectroscopy, elemental analysis, ellipsometry, GPC etc. All of them closely agree with each other. Attempts were made to expand the applicability of this novel way of material synthesis. HILIC is known as a premium separation mode for polar analytes. Glycoproteins form an important class of analytes which need better separation columns. Polyacrylamide coated nonporous colloidal silica is shown here to be a better column packing material. Combined results show that AGET ATRP can be a better and simpler alternative to ATRP for grafting polyacrylamide onto silica based substrates. Future efforts can possibly lead to the expansion of the applicability of this method for making materials for many other separation methods.

  8. Advanced Global Atmospheric Gases Experiment (AGAGE)

    NASA Technical Reports Server (NTRS)

    Weiss, R. F.

    1998-01-01

    The Advanced Global Atmospheric Gases Experiment (AGAGE) is an ongoing research project, for which the work carried out by the Scripps Institution of Oceanography. Due to the need to complete AGAGE activities specifically funded under NAGW-2034 that had been delayed, a no-cost extension to this grant was obtained, creating an overlap period between the two grants. Because the AGAGE project is continuing, and a Final Project Report is required only because of the change in grant numbers, it is most appropriate to submit for this report the Introduction and Accomplishments sections which appear on pages 1-62 of the October 1998 AGAGE renewal proposal. A copy of the complete proposal is attached.

  9. Advanced Global Atmospheric Gases Experiment (AGAGE)

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald G.; Kurylo, Michael (Technical Monitor)

    2004-01-01

    We seek funding from NASA for the third year (2005) of the four-year period January 1, 2003 - December 31, 2006 for continued support of the MIT contributions to the multi-national global atmospheric trace species measurement program entitled Advanced Global Atmospheric Gases Experiment (AGAGE). The case for real-time high-frequency measurement networks like AGAGE is very strong and the observations and their interpretation are widely recognized for their importance to ozone depletion and climate change studies and to verification issues arising from the Montreal Protocol (ozone) and Kyoto Protocol (climate). The proposed AGAGE program is distinguished by its capability to measure over the globe at high frequency almost all of the important species in the Montreal Protocol and almost all of the significant non-CO2 gases in the Kyoto Protocol.

  10. Analysis of colloid transport

    SciTech Connect

    Travis, B.J.; Nuttall, H.E.

    1985-12-31

    The population balance methodology is described and applied to the transport and capture of polydispersed colloids in packed columns. The transient model includes particle growth, capture, convective transport, and dispersion. We also follow the dynamic accumulation of captured colloids on the solids. The multidimensional parabolic partial differential equation was solved by a recently enhanced method of characteristics technique. This computational technique minimized numerical dispersion and is computationally very fast. The FORTRAN 77 code ran on a VAX-780 in less than a minute and also runs on an IBM-AT using the Professional FORTRAN compiler. The code was extensively tested against various simplified cases and against analytical models. The packed column experiments by Saltelli et al. were re-analyzed incorporating the experimentally reported size distribution of the colloid feed material. Colloid capture was modeled using a linear size dependent filtration function. The effects of a colloid size dependent filtration factor and various initial colloid size distributions on colloid migration and capture were investigated. Also, we followed the changing colloid size distribution as a function of position in the column. Some simple arguments are made to assess the likelihood of colloid migration at a potential NTS Yucca Mountain waste disposal site. 10 refs., 3 figs., 1 tab.

  11. Advanced Thin Ionization Calorimeter (ATIC) Balloon Experiment

    NASA Technical Reports Server (NTRS)

    Wefel, John P.; Guzik, T. Gregory

    2001-01-01

    During grant NAG5-5064, Louisiana State University (LSU) led the ATIC team in the development, construction, testing, accelerator validation, pre-deployment integration and flight operations of the Advanced Thin Ionization Calorimeter (ATIC) Balloon Experiment. This involved interfacing among the ATIC collaborators (UMD, NRL/MSFC, SU, MSU, WI, SNU) to develop a new balloon payload based upon a fully active calorimeter, a carbon target, a scintillator strip hodoscope and a pixilated silicon solid state detector for a detailed investigation of the very high energy cosmic rays to energies beyond 10(exp 14) eV/nucleus. It is in this very high energy region that theory predicts changes in composition and energy spectra related to the Supernova Remnant Acceleration model for cosmic rays below the "knee" in the all-particle spectrum. This report provides a documentation list, details the anticipated ATIC science return, describes the particle detection principles on which the experiment is based, summarizes the simulation results for the system, describes the validation work at the CERN SPS accelerator and details the balloon flight configuration. The ATIC experiment had a very successful LDB flight from McMurdo, Antarctica in 12/00 - 1/01. The instrument performed well for the entire 15 days. Preliminary data analysis shows acceptable charge resolution and an all-particle power law energy deposition distribution not inconsistent with previous measurements. Detailed analysis is underway and will result in new data on the cosmic ray charge and energy spectra in the GeV - TeV energy range. ATIC is currently being refurbished in anticipation of another LDB flight in the 2002-03 period.

  12. Colloidal Phenomena.

    ERIC Educational Resources Information Center

    Russel, William B.; And Others

    1979-01-01

    Described is a graduate level engineering course offered at Princeton University in colloidal phenomena stressing the physical and dynamical side of colloid science. The course outline, reading list, and requirements are presented. (BT)

  13. Diagnostics for advanced laser acceleration experiments

    SciTech Connect

    Misuri, Alessio

    2002-06-01

    The first proposal for plasma based accelerators was suggested by 1979 by Tajima and Dawson. Since then there has been a tremendous progress both theoretically and experimentally. The theoretical progress is particularly due to the growing interest in the subject and to the development of more accurate numerical codes for the plasma simulations (especially particle-in-cell codes). The experimental progress follows from the development of multi-terawatt laser systems based on the chirped-pulse amplification technique. These efforts have produced results in several experiments world-wide, with the detection of accelerated electrons of tens of MeV. The peculiarity of these advanced accelerators is their ability to sustain extremely large acceleration gradients. In the conventional radio frequency linear accelerators (RF linacs) the acceleration gradients are limited roughly to 100 MV/m; this is partially due to breakdown which occurs on the walls of the structure. The electrical breakdown is originated by the emission of the electrons from the walls of the cavity. The electrons cause an avalanche breakdown when they reach other metal parts of the RF linacs structure.

  14. ADX - Advanced Divertor and RF Tokamak Experiment

    NASA Astrophysics Data System (ADS)

    Greenwald, Martin; Labombard, Brian; Bonoli, Paul; Irby, Jim; Terry, Jim; Wallace, Greg; Vieira, Rui; Whyte, Dennis; Wolfe, Steve; Wukitch, Steve; Marmar, Earl

    2015-11-01

    The Advanced Divertor and RF Tokamak Experiment (ADX) is a design concept for a compact high-field tokamak that would address boundary plasma and plasma-material interaction physics challenges whose solution is critical for the viability of magnetic fusion energy. This device would have two crucial missions. First, it would serve as a Divertor Test Tokamak, developing divertor geometries, materials and operational scenarios that could meet the stringent requirements imposed in a fusion power plant. By operating at high field, ADX would address this problem at a level of power loading and other plasma conditions that are essentially identical to those expected in a future reactor. Secondly, ADX would investigate the physics and engineering of high-field-side launch of RF waves for current drive and heating. Efficient current drive is an essential element for achieving steady-state in a practical, power producing fusion device and high-field launch offers the prospect of higher efficiency, better control of the current profile and survivability of the launching structures. ADX would carry out this research in integrated scenarios that simultaneously demonstrate the required boundary regimes consistent with efficient current drive and core performance.

  15. Assembly of Colloidal Aggregates by Electrohydrodynamic Flow: Kinetic Experiments and Scaling Analysis

    NASA Technical Reports Server (NTRS)

    Ristenpart, W. D.; Aksay, I. A.; Saville, D. A.

    2004-01-01

    Electric fields generate transverse flows near electrodes that sweep colloidal particles into densely packed assemblies. We interpret this behavior in terms of electrohydrodynamic motion stemming from distortions of the field by the particles that alter the body force distribution in the electrode charge polarization layer. A scaling analysis shows how the action of the applied electric field generates fluid motion that carries particles toward one another. The resulting fluid velocity is proportional to the square of the applied field and decreases inversely with frequency. Experimental measurements of the particle aggregation rate accord with the electrohydrodynamic theory over a wide range of voltages and frequencies.

  16. Driving magnetic colloidal polymers

    NASA Astrophysics Data System (ADS)

    Dempster, Joshua; Olvera de La Cruz, Monica

    Magnetic colloids are of growing interest for applications such as drug delivery and in vitro tissue growth. Recent experiments have synthesized 1D chains of magnetic colloids into permanent colloidal polymers. We study magnetic colloidal polymers theoretically and computationally under the influence of time-varying external fields and find a rich set of controllable, dynamic conformations. By iterating through a sequence of conformations, these polymers can perform mechanical functions. We discuss possible roles for these polymers beyond those considered for single colloids. This work was supported as part of the Center for Bio-Inspired Energy Science, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0000989.

  17. Advanced photoinjector experiment photogun commissioning results

    NASA Astrophysics Data System (ADS)

    Sannibale, F.; Filippetto, D.; Papadopoulos, C. F.; Staples, J.; Wells, R.; Bailey, B.; Baptiste, K.; Corlett, J.; Cork, C.; De Santis, S.; Dimaggio, S.; Doolittle, L.; Doyle, J.; Feng, J.; Garcia Quintas, D.; Huang, G.; Huang, H.; Kramasz, T.; Kwiatkowski, S.; Lellinger, R.; Moroz, V.; Norum, W. E.; Padmore, H.; Pappas, C.; Portmann, G.; Vecchione, T.; Vinco, M.; Zolotorev, M.; Zucca, F.

    2012-10-01

    The Advanced Photoinjector Experiment (APEX) at the Lawrence Berkeley National Laboratory is dedicated to the development of a high-brightness high-repetition rate (MHz-class) electron injector for x-ray free-electron laser (FEL) and other applications where high repetition rates and high brightness are simultaneously required. The injector is based on a new concept rf gun utilizing a normal-conducting (NC) cavity resonating in the VHF band at 186 MHz, and operating in continuous wave (cw) mode in conjunction with high quantum efficiency photocathodes capable of delivering the required charge at MHz repetition rates with available laser technology. The APEX activities are staged in three phases. In phase 0, the NC cw gun is built and tested to demonstrate the major milestones to validate the gun design and performance. Also, starting in phase 0 and continuing in phase I, different photocathodes are tested at the gun energy and at full repetition rate for validating candidate materials to operate in a high-repetition rate FEL. In phase II, a room-temperature pulsed linac is added for accelerating the beam at several tens of MeV to reduce space charge effects and allow the measurement of the brightness of the beam from the gun when integrated in an injector scheme. The installation of the phase 0 beam line and the commissioning of the VHF gun are completed, phase I components are under fabrication, and initial design and specification of components and layout for phase II are under way. This paper presents the phase 0 commissioning results with emphasis on the experimental milestones that have successfully demonstrated the APEX gun capability of operating at the required performance.

  18. Sedimentation and Crystallization of Hard-Sphere Colloidal Suspensions: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Davis, Kevin Eugene

    Sedimentation and ultrafiltration are important processes for removing solids from suspensions. The Kynch theory describes the transient settling of non-colloidal particles forming an incompressible sediment by providing a solution to the convective conservation equation. This solution predicts the evolution of several different regions. Subsequent treatments have accounted for compressibility within the sediment. These modifications, nevertheless, rely entirely on Kynch theory for analytical description, differing only by the assumed boundary condition imposed by the sediment. We present a model of sedimentation for colloidal systems by including a diffusion term in the governing equation. In the regions above the sediment, this term acts as a small perturbation to the Kynch theory. Within the sediment, owing to the high volume fraction, diffusion is comparable to convection. Slow compression to the maximum volume fraction contrasts the incompressibility of the Kynch theory. Application of the method of matched asymptotic expansions to the conservation equation enables us to complete a description of the settling process, in particular, the volume fraction evolution within the sediment. This method is also applied to the related ultrafiltration process. Colloidal dispersions exhibit thermodynamic properties similar to molecular systems, including a hard-sphere disorder -to-order transition, i.e. freezing or crystallization, at particle volume fractions above 0.50. Throughout concentrated suspensions investigators have observed nucleation and growth of small ordered regions. Our dilute suspensions of organophilic silica in cyclohexane depend on settling to concentrate particles. In contrast to the above we observe ordered sediments produced by one-dimensional crystal growth. The slow sedimentation of small particles permits rearrangement into the iridescent ordered structure at the phase boundary. Suspensions with particle sizes of up to 0.34mum easily form fully

  19. Shear-induced breaking of cages in colloidal glasses: Scattering experiments and mode coupling theory.

    PubMed

    Amann, Christian P; Denisov, Dmitry; Dang, Minh Triet; Struth, Bernd; Schall, Peter; Fuchs, Matthias

    2015-07-21

    We employ x-ray scattering on sheared colloidal suspensions and mode coupling theory to study structure factor distortions of glass-forming systems under shear. We find a transition from quadrupolar elastic distortion at small strains to quadrupolar and hexadecupolar modes in the stationary state. The latter are interpreted as signatures of plastic rearrangements in homogeneous, thermalized systems. From their transient evolution with strain, we identify characteristic strain and length-scale values where these plastic rearrangements dominate. This characteristic strain coincides with the maximum of the shear stress versus strain curve, indicating the proliferation of plastic flow. The hexadecupolar modes dominate at the wavevector of the principal peak of the equilibrium structure factor that is related to the cage-effect in mode coupling theory. We hence identify the structural signature of plastic flow of glasses. PMID:26203034

  20. Sentinel node biopsy in melanoma using technetium-99m rhenium colloid: the London experience.

    PubMed

    Temple, C L; Scilley, C G; Engel, C J; Shum, D T; Lohmann, R C; Mattar, A G; Zabel, P L

    2000-11-01

    Nodal metastases in patients with melanoma identify a reduction of survival by 50%; however, elective lymph node dissection (ELND) has not been shown clearly to improve survival. Morton's technique of sentinel node biopsy, using preoperative lymphoscintigraphy and intraoperative blue dye, addresses elegantly the controversy regarding ELND. Sentinel node biopsy has been shown to stage the patient accurately because metastases from melanoma follow an orderly progression from the sentinel node to the remainder of the basin. Fifty-six consecutive patients with American Joint Committee on Cancer stage 1b or 2 melanoma seen at the London Health Sciences Center between July 1998 and January 2000 were enrolled prospectively to undergo sentinel node biopsy. Preoperative lymphoscintigraphy was conducted in the nuclear medicine department. A total of 10 to 15 MBq (0.27-0.41 mCi) of technetium 99m (99mTc) rhenium colloid or filtered sulfur colloid was injected intradermally around the biopsy scar. Images were obtained to localize all draining nodal basins. The location of the sentinel node was marked on the skin. The patient was taken to the operating room and anesthetized. Isosulfan blue dye was injected intradermally around the biopsy scar. A hand-held gamma probe was used intraoperatively as a guide to the first draining node. Blue-stained lymphatic channels aided in the dissection. Sentinel node localization was successful in 55 of 56 patients, for an overall success rate of 98%. Preoperative lymphoscintigraphy identified a sentinel node in an unpredictable location in 32% of patients. On average, 2.3 sentinel nodes per patient were identified on the initial scan, and 2.2 sentinel nodes per patient were recovered at surgery. Both 99mTc rhenium and filtered sulfur colloid showed no substantial differences in tracer uptake and retention in the sentinel node. Twelve patients had a positive sentinel node on routine histology, and 11 patients subsequently underwent completion

  1. Shear-induced breaking of cages in colloidal glasses: Scattering experiments and mode coupling theory

    SciTech Connect

    Amann, Christian P. Fuchs, Matthias; Denisov, Dmitry; Dang, Minh Triet; Schall, Peter; Struth, Bernd

    2015-07-21

    We employ x-ray scattering on sheared colloidal suspensions and mode coupling theory to study structure factor distortions of glass-forming systems under shear. We find a transition from quadrupolar elastic distortion at small strains to quadrupolar and hexadecupolar modes in the stationary state. The latter are interpreted as signatures of plastic rearrangements in homogeneous, thermalized systems. From their transient evolution with strain, we identify characteristic strain and length-scale values where these plastic rearrangements dominate. This characteristic strain coincides with the maximum of the shear stress versus strain curve, indicating the proliferation of plastic flow. The hexadecupolar modes dominate at the wavevector of the principal peak of the equilibrium structure factor that is related to the cage-effect in mode coupling theory. We hence identify the structural signature of plastic flow of glasses.

  2. Shear-induced breaking of cages in colloidal glasses: Scattering experiments and mode coupling theory

    NASA Astrophysics Data System (ADS)

    Amann, Christian P.; Denisov, Dmitry; Dang, Minh Triet; Struth, Bernd; Schall, Peter; Fuchs, Matthias

    2015-07-01

    We employ x-ray scattering on sheared colloidal suspensions and mode coupling theory to study structure factor distortions of glass-forming systems under shear. We find a transition from quadrupolar elastic distortion at small strains to quadrupolar and hexadecupolar modes in the stationary state. The latter are interpreted as signatures of plastic rearrangements in homogeneous, thermalized systems. From their transient evolution with strain, we identify characteristic strain and length-scale values where these plastic rearrangements dominate. This characteristic strain coincides with the maximum of the shear stress versus strain curve, indicating the proliferation of plastic flow. The hexadecupolar modes dominate at the wavevector of the principal peak of the equilibrium structure factor that is related to the cage-effect in mode coupling theory. We hence identify the structural signature of plastic flow of glasses.

  3. Advanced Undergraduate Experiments in Thermoanalytical Chemistry.

    ERIC Educational Resources Information Center

    Hill, J. O.; Magee, R. J.

    1988-01-01

    Describes several experiments using the techniques of thermal analysis and thermometric titrimetry. Defines thermal analysis and several recent branches of the technique. Notes most of the experiments use simple equipment and standard laboratory techniques. (MVL)

  4. Colloid facilitated transport of humic substances in soil: laboratory experiment and modeling calculation.

    NASA Astrophysics Data System (ADS)

    Dinu, Marina; Moiseenko, Tatyana

    2016-04-01

    An understanding of ability to predict the fate and transport of colloids in soil systems are of great importance in many environmental and industrial applications. Especially, in the case study sizes and zeta potentials of lignin and humus components (as a parameter reflecting the mobility and tread of organic substances). The objects of investigation were water extracts of gleepodzolic soil of European territory of Russia and Western Siberia, as well as humus substances extracted from this soil. In this study, evaluation of size, molecular weight distribution and zeta potential were used to predict the mobility of the organic component fractions of the soil. Fractionation was performed using multistage filtration plant (100 Da) and measuring physic-chemical parameters measured with the Malvern Zetasizer Nano ZSP. Significant differences in the distribution of organic matter on the molecular weight, charge (sign) of the zeta potential and the size of the sample of European Russia in comparison with samples of Western Siberia have been found. Also, laboratory studies have demonstrated of any differences in physicochemical parameters as infrared spectra, ultraviolet spectra, complexing ability of samples of the same soil type but different areas of Russia. The results can be used in the prediction of the migration ability of fractions humus substances and their stability at change physic-chemical conditions (the coefficient of mobility of the organic components by calculated in MathCad). This work was supported by the grant № 14-17-00460 RSF from 07.11.2014

  5. Radioactive colloidal gold in the treatment of endometrial cancer: Mayo Clinic experience, 1952-1976

    SciTech Connect

    Fountain, K.S.; Malkasian, G.D. Jr.

    1981-05-15

    A review of 1670 patients with endometrial cancer who were treated between 1952 and 1976 revealed that 15 patients had received radioactive colloidal gold as an adjunct to surgery. Most of the patients had follow-up more than ten years, and all had microscopic tumor contamination of the peritoneal cavity. Of the 15 patients, 13 had biopsy of peritoneal metastases and underwent resection of gross metastatic lesions that were more than 2 mm in diameter. The other two patients had direct extension of the tumor through the uterus into the peritoneal cavity without visible metastasis. The radiogold was inserted from 4-37 days after the initial surgical procedure. The dosage ranged from 100-140 mCi. At follow-up, from 11 years seven months to 24 years two months after treatment, seven patients were alive without evidence of disease. Three died of intercurrent disease, 16 years, and 14 years, and 14 years two months after treatment. Five patients died of cancer, two with local recurrence and three with distant metastases to lung or bone (or both).

  6. Radioactive colloidal gold in the treatment of endometrial cancer: Mayo Clinic experience, 1952 to 1976

    SciTech Connect

    Fountain, K.S.; Malkasian, G.D. Jr.

    1981-05-15

    A review of 1670 patients with endometrial cancer who were treated between 1952 and 1976 revealed that 15 patients had received radioactive colloidal gold as an adjunct to surgery. Most of the patients had follow-up of more than ten years, and all had microscopic tumor contamination of the peritoneal cavity. Of the 15 patients, 13 had biopsy of peritoneal metastases and underwent resection of gross metastatic lesions that were more than 2 mm in diameter. The other two patients had direct extension of the tumor through the uterus into the peritoneal cavity without visible metastasis. The radiogold was inserted from 4 to 37 days after the initial surgical procedure. The dosage ranged from 100 to 140 mCi. At follow-up, from 11 years seven months to 24 years two months after treatment, seven patients were alive without evidence of disease. Three died of intercurrent disease, 16, 14 years, and 14 years two months after treatment. Five patients died of cancer, two with local recurrence and three with distant metastases to lung or bone (or both).

  7. Comparing Record Dynamics Predictions with Simulations and Experiments of Aging Colloids

    NASA Astrophysics Data System (ADS)

    Boettcher, Stefan; Becker, Nikolaj; Sibani, Paolo

    2014-03-01

    We describe the spontaneous off-equilibrium relaxation process known as aging in a simple, real-space model: Kinetic constraints bind on-lattice particles together in ``clusters,'' where a phenomenological function of size controls their lifetime. But once a cluster breaks down, its particles can move independently in space, a process akin to ``cage breaking,'' to join other clusters.Known properties of glassy systems emerge, such as spatial heterogeneity and record dynamics. Here we compare our simple model with recent molecular dynamics studies of hard-sphere colloids.We find agreement with the scaling properties of the particles mean square displacement, and the aging properties of the interface energy, of the intermediate scattering function, and of the probability density function of the particle displacements occurring within different time windows. These properties are related to an underlying Poisson process which describes the salient events or quakes which correspond to the break up of clusters and give a coarse-grained description of the model dynamics, confirmed by re-analysis of experimental data. SB acknowledges support from NSF with DMR-grant #1207431, and thanks SDU for its hospitality and the Villum Foundation for support.

  8. Effects of kaolinite colloids on Cd2 + transport through saturated sand under varying ionic strength conditions: Column experiments and modeling approaches

    NASA Astrophysics Data System (ADS)

    Wikiniyadhanee, Rakkreat; Chotpantarat, Srilert; Ong, Say Kee

    2015-11-01

    Column experiments were performed under various ionic strengths (0.0-0.9 mM) using 10 mg L- 1 of Cd2 + without kaolinite colloids and 10 mg L- 1 Cd2 + mixed with 100 mg L- 1 kaolinite colloids. The nonequilibrium two-site model (TSM) described the behavior of both Cd2 + transport and Cd2 + co-transported with kaolinite colloids better than the equilibrium model (CDeq) (R2 = 0.978-0.996). The results showed that an increase in ionic strength negatively impacted the retardation factors (R) of both Cd2 + and Cd2 + mixed with kaolinite colloids. The presence of kaolinite colloids increased the retardation factors of Cd2 + from 7.23 to 7.89, 6.76 to 6.61 and 3.79 to 6.99 for ionic strengths of 0.225, 0.45 and 0.9 mM, respectively. On the other hand, the presence of kaolinite colloids decreased the retardation factor of Cd2 + from 8.13 to 7.83 for ionic strength of 0.0 mM. The fraction of instantaneous sorption sites (f) parameters, kinetic constant for sorption sites (α) and Freundlich constant (Kf) were estimated from HYDRUS-1D of TSM for Cd2 + transport. The fraction of instantaneous sorption sites was found to increase for an increase in ionic strength. Kf values of Cd2 + transport without kaolinite colloids for 0.0, 0.225 and 0.45 mM were found to be higher than those of Cd2 + transport with kaolinite colloids, except for ionic strength of 0.9 mM. Hence, the presence of kaolinite colloids probably retarded the mobility of Cd2 + in porous media for higher ionic strengths. Furthermore, retardation factors and Kf values of both Cd2 + transport and Cd2 + co-transport were shown to decrease when ionic strength increased. Interestingly, according to TSM, the fraction of instantaneous sorption sites tends to increase for an increase in ionic strength, which imply that the mechanism of Cd2 + sorption onto quartz sand can be better described using equilibrium sorption rather than nonequilibrium sorption for an increase in ionic strength.

  9. Effects of kaolinite colloids on Cd²⁺ transport through saturated sand under varying ionic strength conditions: Column experiments and modeling approaches.

    PubMed

    Wikiniyadhanee, Rakkreat; Chotpantarat, Srilert; Ong, Say Kee

    2015-11-01

    Column experiments were performed under various ionic strengths (0.0-0.9 mM) using 10 mg L(-1) of Cd(2+) without kaolinite colloids and 10 mg L(-1) Cd(2+) mixed with 100 mg L(-1) kaolinite colloids. The nonequilibrium two-site model (TSM) described the behavior of both Cd(2+) transport and Cd(2+) co-transported with kaolinite colloids better than the equilibrium model (CD(eq)) (R(2)=0.978-0.996). The results showed that an increase in ionic strength negatively impacted the retardation factors (R) of both Cd(2+) and Cd(2+) mixed with kaolinite colloids. The presence of kaolinite colloids increased the retardation factors of Cd(2+) from 7.23 to 7.89, 6.76 to 6.61 and 3.79 to 6.99 for ionic strengths of 0.225, 0.45 and 0.9 mM, respectively. On the other hand, the presence of kaolinite colloids decreased the retardation factor of Cd(2+) from 8.13 to 7.83 for ionic strength of 0.0 mM. The fraction of instantaneous sorption sites (f) parameters, kinetic constant for sorption sites (α) and Freundlich constant (K(f)) were estimated from HYDRUS-1D of TSM for Cd(2+) transport. The fraction of instantaneous sorption sites was found to increase for an increase in ionic strength. K(f) values of Cd(2+) transport without kaolinite colloids for 0.0, 0.225 and 0.45 mM were found to be higher than those of Cd(2+) transport with kaolinite colloids, except for ionic strength of 0.9 mM. Hence, the presence of kaolinite colloids probably retarded the mobility of Cd(2+) in porous media for higher ionic strengths. Furthermore, retardation factors and K(f) values of both Cd(2+) transport and Cd(2+) co-transport were shown to decrease when ionic strength increased. Interestingly, according to TSM, the fraction of instantaneous sorption sites tends to increase for an increase in ionic strength, which imply that the mechanism of Cd(2+) sorption onto quartz sand can be better described using equilibrium sorption rather than nonequilibrium sorption for an increase in ionic strength. PMID

  10. Organized Assemblies of Colloids Formed at the Poles of Micrometer-Sized Droplets of Liquid Crystal

    PubMed Central

    Wang, Xiaoguang; Miller, Daniel S.; de Pablo, Juan J.

    2014-01-01

    We report on the formation of organized assemblies of 1 μm-in-diameter colloids (polystyrene (PS)) at the poles of water-dispersed droplets (diameters 7 - 20 μm) of nematic liquid crystal (LC). For 4-cyano-4′-pentylbiphenyl droplets decorated with two to five PS colloids, we found 32 distinct arrangements of the colloids to form at the boojums of bipolar droplet configurations. Significantly, all but one of these configurations (a ring comprised of five PS colloids) could be mapped onto a local (non-close packed) hexagonal lattice. To provide insight into the origin of the hexagonal lattice, we investigated planar aqueous—LC interfaces, and found that organized assemblies of PS colloids did not form at these interfaces. Experiments involving the addition of salts revealed that a repulsive interaction of electrostatic origin prevented formation of assemblies at planar interfaces, and that regions of high splay near the poles of the LC droplets generated cohesive interactions between colloids that could overcome the repulsion. Support for this interpretation was obtained from a model that included (i) a long-range attraction between adsorbed colloids and the boojum due to the increasing rate of strain (splay) of LC near the boojum (splay attraction), (ii) an attractive inter-colloid interaction that reflects the quadrupolar symmetry of the strain in the LC around the colloids, and (iii) electrostatic repulsion between colloids. The model predicts that electrostatic repulsion between colloids can lead to a ∼1,000 kBT energy barrier at planar interfaces of LC films, and that the repulsive interaction can be overcome by splay attraction of the colloids to the boojums of the LC droplets. Overall, the results reported in this paper advance our understanding of the directed assembly of colloids at interfaces of LC droplets. PMID:25284139

  11. Advanced beamline automation for biological crystallography experiments.

    PubMed

    Cork, Carl; O'Neill, James; Taylor, John; Earnest, Thomas

    2006-08-01

    An automated crystal-mounting/alignment system has been developed at Lawrence Berkeley National Laboratory and has been installed on three of the protein-crystallography experimental stations at the Advanced Light Source (ALS); it is currently being implemented at synchrotron crystallography beamlines at CHESS, NSLS and the APS. The benefits to using an automounter system include (i) optimization of the use of synchrotron beam time, (ii) facilitation of advanced data-collection techniques, (iii) collection of higher quality data, (iv) reduction of the risk to crystals and (v) exploration of systematic studies of experimental protocols. Developments on the next-generation automounter with improvements in robustness, automated alignment and sample tracking are under way, with an end-to-end data-flow process being developed to allow remote data collection and monitoring. PMID:16855300

  12. EDITORIAL: Colloidal suspensions Colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Petukhov, Andrei; Kegel, Willem; van Duijneveldt, Jeroen

    2011-05-01

    fluid-fluid interface [2]. Together with Remco Tuinier, Henk has recently completed a book in this area which is to appear later this year. A major theme in Henk's research is that of phase transitions in lyotropic liquid crystals. Henk, together with Daan Frenkel and Alain Stroobants, realized in the 1980s that a smectic phase in dispersions of rod-like particles can be stable without the presence of attractive interactions, similar to nematic ordering as predicted earlier by Onsager [3]. Together with Gert-Jan Vroege he wrote a seminal review in this area [4]. Henk once said that 'one can only truly develop one colloidal model system in one's career' and in his case this must be that of gibbsite platelets. Initially Henk's group pursued another polymorph of aluminium hydroxide, boehmite, which forms rod-like particles [5], which already displayed nematic liquid crystal phases. The real breakthrough came when the same precursors treated the produced gibbsite platelets slightly differently. These reliably form a discotic nematic phase [6] and, despite the polydispersity in their diameter, a columnar phase [7]. A theme encompassing a wide range of soft matter systems is that of colloidal dynamics and phase transition kinetics. Many colloidal systems have a tendency to get stuck in metastable states, such as gels or glasses. This is a nuisance if one wishes to study phase transitions, but it is of great practical significance. Such issues feature in many of Henk's publications, and with Valerie Anderson he wrote a highly cited review in this area [8]. Henk Lekkerkerker has also invested significant effort into the promotion of synchrotron radiation studies of colloidal suspensions. He was one of the great supporters of the Dutch-Belgian beamline 'DUBBLE' project at the ESRF [9]. He attended one of the very first experiments in Grenoble in 1999, which led to a Nature publication [7]. He was strongly involved in many other experiments which followed and also has been a

  13. Design of a field experiment for injection of natural colloids in a sandy coastal plain aquifer, Belle W. Baruch Forest Science Institute, Georgetown, South Carolina

    SciTech Connect

    Toran, L.E.; McCarthy, J.F. ); Williams, T.M. . Belle W. Baruch Forest Science Inst.)

    1990-06-01

    This report summarizes the design of field injection experiments that constitute one task in the larger project described in the report Experiments Using Natural Organics.'' In the experiment, we plan to inject a large volume of colloidal organic matter (COM) into a sandy, unconsolidated coastal aquifer and observe the migration of COM into the groundwater flow system. The report provides a brief overview of the research project, including hypotheses to be tested; describes the purpose of the field injection experiments; summarizes the site characterization preliminary to the experiments; and explains the design of the experiments. 11 figs., 5 tabs.

  14. Space Experiments to Advance Beamed Energy Propulsion

    NASA Astrophysics Data System (ADS)

    Johansen, Donald G.

    2010-05-01

    High power microwave sources are now available and usable, with modification, or beamed energy propulsion experiments in space. As output windows and vacuum seals are not needed space is a natural environment for high power vacuum tubes. Application to space therefore improves reliability and performance but complicates testing and qualification. Low power communications satellite devices (TWT, etc) have already been through the adapt-to-space design cycle and this history is a useful pathway for high power devices such as gyrotrons. In this paper, space experiments are described for low earth orbit (LEO) and lunar environment. These experiments are precursors to space application for beamed energy propulsion using high power microwaves. Power generation and storage using cryogenic systems are important elements of BEP systems and also have an important role as part of BEP experiments in the space environment.

  15. Experiment-Based Teaching in Advanced Control Engineering

    ERIC Educational Resources Information Center

    Precup, R.-E.; Preitl, S.; Radac, M.-B.; Petriu, E. M.; Dragos, C.-A.; Tar, J. K.

    2011-01-01

    This paper discusses an experiment-based approach to teaching an advanced control engineering syllabus involving controlled plant analysis and modeling, control structures and algorithms, real-time laboratory experiments, and their assessment. These experiments are structured around the representative case of the longitudinal slip control of an…

  16. EDITORIAL: Colloidal suspensions Colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Petukhov, Andrei; Kegel, Willem; van Duijneveldt, Jeroen

    2011-05-01

    fluid-fluid interface [2]. Together with Remco Tuinier, Henk has recently completed a book in this area which is to appear later this year. A major theme in Henk's research is that of phase transitions in lyotropic liquid crystals. Henk, together with Daan Frenkel and Alain Stroobants, realized in the 1980s that a smectic phase in dispersions of rod-like particles can be stable without the presence of attractive interactions, similar to nematic ordering as predicted earlier by Onsager [3]. Together with Gert-Jan Vroege he wrote a seminal review in this area [4]. Henk once said that 'one can only truly develop one colloidal model system in one's career' and in his case this must be that of gibbsite platelets. Initially Henk's group pursued another polymorph of aluminium hydroxide, boehmite, which forms rod-like particles [5], which already displayed nematic liquid crystal phases. The real breakthrough came when the same precursors treated the produced gibbsite platelets slightly differently. These reliably form a discotic nematic phase [6] and, despite the polydispersity in their diameter, a columnar phase [7]. A theme encompassing a wide range of soft matter systems is that of colloidal dynamics and phase transition kinetics. Many colloidal systems have a tendency to get stuck in metastable states, such as gels or glasses. This is a nuisance if one wishes to study phase transitions, but it is of great practical significance. Such issues feature in many of Henk's publications, and with Valerie Anderson he wrote a highly cited review in this area [8]. Henk Lekkerkerker has also invested significant effort into the promotion of synchrotron radiation studies of colloidal suspensions. He was one of the great supporters of the Dutch-Belgian beamline 'DUBBLE' project at the ESRF [9]. He attended one of the very first experiments in Grenoble in 1999, which led to a Nature publication [7]. He was strongly involved in many other experiments which followed and also has been a

  17. Advanced tracking and data relay experiment study: Multimode transponder experiment

    NASA Technical Reports Server (NTRS)

    Cnossen, R. S.

    1973-01-01

    A series of experiments utilizing a multimode transponder mounted in an aircraft working either through a spacecraft or directly with a ground station is studied. The purpose of the experiments is to determine the best modulation and encoding techniques for combating RFI and multipath propagation and to determine the characteristics of VHF and UHF RFI in discreet bands. The experiments would also determine the feasibility and accuracy of range and range rate measurements with the various modulation and encoding techniques.

  18. Advances in NIF Shock Timing Experiments

    NASA Astrophysics Data System (ADS)

    Robey, Harry

    2012-10-01

    Experiments are underway to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to multiple shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of all four shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector). Experiments are now routinely conducted in a mirrored keyhole geometry, which allows for simultaneous diagnosis of the shock timing at both the hohlraum pole and equator. Further modifications are being made to improve the surrogacy to ignition hohlraums by replacing the standard liquid deuterium (D2) capsule fill with a deuterium-tritium (DT) ice layer. These experiments will remove any possible surrogacy difference between D2 and DT as well as incorporate the physics of shock release from the ice layer, which is absent in current experiments. Experimental results and comparisons with numerical simulation are presented.

  19. Ozone Research with Advanced Cooperative Lidar Experiment (ORACLE) Implementation Study

    NASA Technical Reports Server (NTRS)

    Stadler, John H.; Browell, Edward V.; Ismail, Syed; Dudelzak, Alexander E.; Ball, Donald J.

    1998-01-01

    New technological advances have made possible new active remote sensing capabilities from space. Utilizing these technologies, the Ozone Research with Advanced Cooperative Lidar Experiment (ORACLE) will provide high spatial resolution measurements of ozone, clouds and aerosols in the stratosphere and lower troposphere. Simultaneous measurements of ozone, clouds and aerosols will assist in the understanding of global change, atmospheric chemistry and meteorology.

  20. Synthesis and Electrochemistry of Cyclopentadienylcarbonyliron Tetramer: An Advanced Experiment.

    ERIC Educational Resources Information Center

    White, A. J.; Cunningham, Alice J.

    1980-01-01

    Describes an advanced level experiment in which a transition metal cluster compound, cyclopentadienylcarbonyliron tetramer, is synthesized and characterized spectroscopically. Its redox properties are then explored through cyclic voltammetry. (CS)

  1. Rotor-Shaped Cyclopentadienyltetraphenyl-Cyclobutadienecobalt: An Advanced Inorganic Experiment

    ERIC Educational Resources Information Center

    MacFarland, Darren K.; Gorodetzer, Rebecca

    2005-01-01

    Organometallic complex synthesis in advanced inorganic or organic courses usually begin with the synthesis of ferrocene. A synthetic experiment of an alternative compound that has a more interesting structure and the same air stability that makes ferrocene desirable is presented.

  2. An Advanced Undergraduate Nuclear Lifetime experiment.

    ERIC Educational Resources Information Center

    Rollefson, A. A.; Prior, R. M.

    1978-01-01

    Describes an experiment for measuring the lifetime of the 60-keV state in 237-Np which is populated in the alpha decay of 241-Am. The technique used is the delayed coincidence method using a time-to-pulse-height converter. (Author/GA)

  3. Experience with advanced nodal codes at YAEC

    SciTech Connect

    Cacciapouti, R.J.

    1990-01-01

    Yankee Atomic Electric Company (YAEC) has been performing reload licensing analysis since 1969. The basic pressurized water reactor (PWR) methodology involves the use of LEOPARD for cross-section generation, PDQ for radial power distributions and integral control rod worth, and SIMULATE for axial power distributions and differential control rod worth. In 1980, YAEC began performing reload licensing analysis for the Vermont Yankee boiling water reactor (BWR). The basic BWR methodology involves the use of CASMO for cross-section generation and SIMULATE for three-dimensional power distributions. In 1986, YAEC began investigating the use of CASMO-3 for cross-section generation and the advanced nodal code SIMULATE-3 for power distribution analysis. Based on the evaluation, the CASMO-3/SIMULATE-3 methodology satisfied all requirements. After careful consideration, the cost of implementing the new methodology is expected to be offset by reduced computing costs, improved engineering productivity, and fuel-cycle performance gains.

  4. Colloidal Dispersions

    NASA Astrophysics Data System (ADS)

    Russel, W. B.; Saville, D. A.; Schowalter, W. R.

    1992-03-01

    The book covers the physical side of colloid science from the individual forces acting between submicron particles suspended in a liquid through the resulting equilibrium and dynamic properties. The relevant forces include Brownian motion, electrostatic repulsion, dispersion attraction, both attraction and repulsion due to soluble polymer, and viscous forces due to relative motion between the particles and the liquid. The balance among Brownian motion and the interparticle forces decides the questions of stability and phase behavior. Imposition of external fields produces complex effects, i.e. electrokinetic phenomena (electric field), sedimentation (gravitational field), diffusion (concentration/chemical potential gradient), and non-Newtonian rheology (shear field). The treatment aims to impart a sound, quantitative understanding based on fundamental theory and experiments with well-characterized model systems. This broad grasp of the fundamentals lends insight and helps to develop the intuitive sense needed to isolate essential features of technological problems and design critical experiments. Some exposure to fluid mechanics, statistical mechanics, and electricity and magnetism is assumed, but each subject is reintroduced in a self-contained manner.

  5. Phase camera experiment for Advanced Virgo

    NASA Astrophysics Data System (ADS)

    Agatsuma, Kazuhiro; van Beuzekom, Martin; van der Schaaf, Laura; van den Brand, Jo

    2016-07-01

    We report on a study of the phase camera, which is a frequency selective wave-front sensor of a laser beam. This sensor is utilized for monitoring sidebands produced by phase modulations in a gravitational wave (GW) detector. Regarding the operation of the GW detectors, the laser modulation/demodulation method is used to measure mirror displacements and used for the position controls. This plays a significant role because the quality of controls affect the noise level of the GW detector. The phase camera is able to monitor each sideband separately, which has a great benefit for the manipulation of the delicate controls. Also, overcoming mirror aberrations will be an essential part of Advanced Virgo (AdV), which is a GW detector close to Pisa. Especially low-frequency sidebands can be affected greatly by aberrations in one of the interferometer cavities. The phase cameras allow tracking such changes because the state of the sidebands gives information on mirror aberrations. A prototype of the phase camera has been developed and is currently tested. The performance checks are almost completed and the installation of the optics at the AdV site has started. After the installation and commissioning, the phase camera will be combined to a thermal compensation system that consists of CO2 lasers and compensation plates. In this paper, we focus on the prototype and show some limitations from the scanner performance.

  6. EDITORIAL: Colloidal dispersions in external fields Colloidal dispersions in external fields

    NASA Astrophysics Data System (ADS)

    Löwen, Hartmut

    2012-11-01

    Colloidal dispersions have long been proven as pivotal model systems for equilibrium phase transition such as crystallization, melting and liquid-gas phase transition. The last decades have revealed that this is also true for nonequilibrium phenomena. In fact, the fascinating possibility to track the individual trajectories of colloidal particles has greatly advanced our understanding of collective behaviour in classical many-body systems and has helped to reveal the underlying physical principles of glass transition, crystal nucleation, and interfacial dynamics (to name just a few typical nonequilibrium effects). External fields can be used to bring colloids out of equilibrium in a controlled way. Different kinds of external fields can be applied to colloidal dispersions, namely shear flow, electric, magnetic and laser-optical fields, and confinement. Typical research areas can be sketched with the by now traditional complexity diagram (figure 1). The complexity of the colloidal system itself as embodied in statistical degrees of freedom is shown on the x-axis while the complexity of the problem posed, namely bulk, an inhomogeneity in equilibrium, steady state nonequilibrium and full time-dependent nonequilibrium are shown on the y-axis. The different external fields which can be imposed are indicated by the different hatched areas. figure1 Figure 1. Diagram of complexity for colloidal dispersions in external fields: while the x-axis shows the complexity of the system, the y-axis shows the complexity of the problem. Regions which can be accessed by different kinds of external fields are indicated. The arrows indicate recent research directions. Active particles are also indicated with a special complexity of internal degrees of freedom [1]. This collection of papers reflects the scientific programme of the International Conference on Colloidal Dispersions in External Fields III (CODEF III) which took place in Bonn-Bad Godesberg from 20-23 March 2012. This was the

  7. Advances in the Remote Glow Discharge Experiment

    NASA Astrophysics Data System (ADS)

    Dominguez, Arturo; Zwicker, A.; Rusaits, L.; McNulty, M.; Sosa, Carl

    2014-10-01

    The Remote Glow Discharge Experiment (RGDX) is a DC discharge plasma with variable pressure, end-plate voltage and externally applied axial magnetic field. While the experiment is located at PPPL, a webcam displays the live video online. The parameters (voltage, magnetic field and pressure) can be controlled remotely in real-time by opening a URL which shows the streaming video, as well as a set of Labview controls. The RGDX is designed as an outreach tool that uses the attractive nature of a plasma in order to reach a wide audience and extend the presence of plasma physics and fusion around the world. In March 2014, the RGDX was made publically available and, as of early July, it has had approximately 3500 unique visits from 107 countries and almost all 50 US states. We present recent upgrades, including the ability to remotely control the distance between the electrodes. These changes give users the capability of measuring Paschen's Law remotely and provides a comprehensive introduction to plasma physics to those that do not have access to the necessary equipment.

  8. Experiments investigating advanced materials under thermomechanical loading

    NASA Technical Reports Server (NTRS)

    Bartolotta, Paul A.

    1988-01-01

    Many high temperature aircraft and rocket engine components experience large mechanical loads as well as severe thermal gradients and transients. These nonisothermal conditions are often large enough to cause inelastic deformations, which are the ultimate cause for failure in those parts. A way to alleviate this problem is through improved engine designs based on better predictions of thermomechanical material behavior. To address this concern, an experimental effort was recently initiated within the Hot Section Technology (HOST) program at Lewis. As part of this effort, two new test systems were added to the Fatigue and Structures Lab., which allowed thermomechanical tests to be conducted under closely controlled conditions. These systems are now being used for thermomechanical testing for the Space Station Receiver program, and will be used to support development of metal matrix composites.

  9. Hexadecapolar colloids

    PubMed Central

    Senyuk, Bohdan; Puls, Owen; Tovkach, Oleh M.; Chernyshuk, Stanislav B.; Smalyukh, Ivan I.

    2016-01-01

    Outermost occupied electron shells of chemical elements can have symmetries resembling that of monopoles, dipoles, quadrupoles and octupoles corresponding to filled s-, p-, d- and f-orbitals. Theoretically, elements with hexadecapolar outer shells could also exist, but none of the known elements have filled g-orbitals. On the other hand, the research paradigm of ‘colloidal atoms' displays complexity of particle behaviour exceeding that of atomic counterparts, which is driven by DNA functionalization, geometric shape and topology and weak external stimuli. Here we describe elastic hexadecapoles formed by polymer microspheres dispersed in a liquid crystal, a nematic fluid of orientationally ordered molecular rods. Because of conically degenerate boundary conditions, the solid microspheres locally perturb the alignment of the nematic host, inducing hexadecapolar distortions that drive anisotropic colloidal interactions. We uncover physical underpinnings of formation of colloidal elastic hexadecapoles and describe the ensuing bonding inaccessible to elastic dipoles, quadrupoles and other nematic colloids studied previously. PMID:26864184

  10. Colloidal polypyrrole

    DOEpatents

    Armes, Steven P.; Aldissi, Mahmoud

    1990-01-01

    Processable electrically conductive latex polymer compositions including colloidal particles of an oxidized, polymerized aromatic heterocyclic monomer, a stabilizing effective amount of a vinyl pyridine-containing polymer and dopant anions and a method of preparing such polymer compositions are disclosed.

  11. Hexadecapolar colloids

    NASA Astrophysics Data System (ADS)

    Senyuk, Bohdan; Puls, Owen; Tovkach, Oleh M.; Chernyshuk, Stanislav B.; Smalyukh, Ivan I.

    2016-02-01

    Outermost occupied electron shells of chemical elements can have symmetries resembling that of monopoles, dipoles, quadrupoles and octupoles corresponding to filled s-, p-, d- and f-orbitals. Theoretically, elements with hexadecapolar outer shells could also exist, but none of the known elements have filled g-orbitals. On the other hand, the research paradigm of `colloidal atoms' displays complexity of particle behaviour exceeding that of atomic counterparts, which is driven by DNA functionalization, geometric shape and topology and weak external stimuli. Here we describe elastic hexadecapoles formed by polymer microspheres dispersed in a liquid crystal, a nematic fluid of orientationally ordered molecular rods. Because of conically degenerate boundary conditions, the solid microspheres locally perturb the alignment of the nematic host, inducing hexadecapolar distortions that drive anisotropic colloidal interactions. We uncover physical underpinnings of formation of colloidal elastic hexadecapoles and describe the ensuing bonding inaccessible to elastic dipoles, quadrupoles and other nematic colloids studied previously.

  12. Hexadecapolar colloids.

    PubMed

    Senyuk, Bohdan; Puls, Owen; Tovkach, Oleh M; Chernyshuk, Stanislav B; Smalyukh, Ivan I

    2016-01-01

    Outermost occupied electron shells of chemical elements can have symmetries resembling that of monopoles, dipoles, quadrupoles and octupoles corresponding to filled s-, p-, d- and f-orbitals. Theoretically, elements with hexadecapolar outer shells could also exist, but none of the known elements have filled g-orbitals. On the other hand, the research paradigm of 'colloidal atoms' displays complexity of particle behaviour exceeding that of atomic counterparts, which is driven by DNA functionalization, geometric shape and topology and weak external stimuli. Here we describe elastic hexadecapoles formed by polymer microspheres dispersed in a liquid crystal, a nematic fluid of orientationally ordered molecular rods. Because of conically degenerate boundary conditions, the solid microspheres locally perturb the alignment of the nematic host, inducing hexadecapolar distortions that drive anisotropic colloidal interactions. We uncover physical underpinnings of formation of colloidal elastic hexadecapoles and describe the ensuing bonding inaccessible to elastic dipoles, quadrupoles and other nematic colloids studied previously. PMID:26864184

  13. Hexadecapolar Colloids

    DOE PAGESBeta

    Senyuk, Bohdan; Puls, Owen; Tovkach, Oleh M.; Chernyshuk, Stanislav B.; Smalyukh, Ivan I.

    2016-02-11

    Outermost occupied electron shells of chemical elements can have symmetries resembling that of monopoles, dipoles, quadrupoles and octupoles corresponding to filled s-, p-, d- and forbitals. Theoretically, elements with hexadecapolar outer shells could also exist, but none of the known elements have filled g-orbitals. On the other hand, the research paradigm of ‘colloidal atoms’ displays complexity of particle behaviour exceeding that of atomic counterparts, which is driven by DNA functionalization, geometric shape and topology and weak external stimuli. We describe elastic hexadecapoles formed by polymer microspheres dispersed in a liquid crystal, a nematic fluid of orientationally ordered molecular rods. Becausemore » of conically degenerate boundary conditions, the solid microspheres locally perturb the alignment of the nematic host, inducing hexadecapolar distortions that drive anisotropic colloidal interactions. We uncover physical underpinnings of formation of colloidal elastic hexadecapoles and report the ensuing bonding inaccessible to elastic dipoles, quadrupoles and other nematic colloids studied previously.« less

  14. Spherical colloidal photonic crystals.

    PubMed

    Zhao, Yuanjin; Shang, Luoran; Cheng, Yao; Gu, Zhongze

    2014-12-16

    generated by evaporation-induced nanoparticle crystallization or polymerization of ordered nanoparticle crystallization arrays. In particular, because microfluidics was used for the generation of the droplet templates, the development of spherical colloidal PhCs has progressed significantly. These new strategies not only ensure monodispersity, but also increase the structural and functional diversity of the PhC beads, paving the way for the development of advanced optoelectronic devices. In this Account, we present the research progress on spherical colloidal PhCs, including their design, preparation, and potential applications. We outline various types of spherical colloidal PhCs, such as close-packed, non-close-packed, inverse opal, biphasic or multiphasic Janus structured, and core-shell structured geometries. Based on their unique optical properties, applications of the spherical colloidal PhCs for displays, sensors, barcodes, and cell culture microcarriers are presented. Future developments of the spherical colloidal PhC materials are also envisioned. PMID:25393430

  15. Safety Assurance for Irradiating Experiments in the Advanced Test Reactor

    SciTech Connect

    T. A. Tomberlin; S. B. Grover

    2004-11-01

    The Advanced Test Reactor (ATR), located at the Idaho National Engineering and Environmental Laboratory (INEEL), was specifically designed to provide a high neutron flux test environment for conducting a variety of experiments. This paper addresses the safety assurance process for two general types of experiments conducted in the ATR facility and how the safety analyses for experiments are related to the ATR safety basis. One type of experiment is more routine and generally represents greater risks; therefore, this type of experiment is addressed in more detail in the ATR safety basis. This allows the individual safety analysis for this type of experiment to be more standardized. The second type of experiment is defined in more general terms in the ATR safety basis and is permitted under more general controls. Therefore, the individual safety analysis for the second type of experiment tends to be more unique and is tailored to each experiment.

  16. Magnetic Assisted Colloidal Pattern Formation

    NASA Astrophysics Data System (ADS)

    Yang, Ye

    Pattern formation is a mysterious phenomenon occurring at all scales in nature. The beauty of the resulting structures and myriad of resulting properties occurring in naturally forming patterns have attracted great interest from scientists and engineers. One of the most convenient experimental models for studying pattern formation are colloidal particle suspensions, which can be used both to explore condensed matter phenomena and as a powerful fabrication technique for forming advanced materials. In my thesis, I have focused on the study of colloidal patterns, which can be conveniently tracked in an optical microscope yet can also be thermally equilibrated on experimentally relevant time scales, allowing for ground states and transitions between them to be studied with optical tracking algorithms. In particular, I have focused on systems that spontaneously organize due to particle-surface and particle-particle interactions, paying close attention to systems that can be dynamically adjusted with an externally applied magnetic or acoustic field. In the early stages of my doctoral studies, I developed a magnetic field manipulation technique to quantify the adhesion force between particles and surfaces. This manipulation technique is based on the magnetic dipolar interactions between colloidal particles and their "image dipoles" that appear within planar substrate. Since the particles interact with their own images, this system enables massively parallel surface force measurements (>100 measurements) in a single experiment, and allows statistical properties of particle-surface adhesion energies to be extracted as a function of loading rate. With this approach, I was able to probe sub-picoNewton surface interactions between colloidal particles and several substrates at the lowest force loading rates ever achieved. In the later stages of my doctoral studies, I focused on studying patterns formed from particle-particle interaction, which serve as an experimental model of

  17. Simulation of nucleation in almost hard-sphere colloids: The discrepancy between experiment and simulation persists

    NASA Astrophysics Data System (ADS)

    Filion, L.; Ni, R.; Frenkel, D.; Dijkstra, M.

    2011-04-01

    In this paper we examine the phase behavior of the Weeks-Chandler-Andersen (WCA) potential with βɛ = 40. Crystal nucleation in this model system was recently studied by Kawasaki and Tanaka [Proc. Natl. Acad. Sci. U.S.A. 107, 14036 (2010)], 10.1021/pr100656u, who argued that the computed nucleation rates agree well with experiment, a finding that contradicted earlier simulation results. Here we report an extensive numerical study of crystallization in the WCA model, using three totally different techniques (Brownian dynamics, umbrella sampling, and forward flux sampling). We find that all simulations yield essentially the same nucleation rates. However, these rates differ significantly from the values reported by Kawasaki and Tanaka and hence we argue that the huge discrepancy in nucleation rates between simulation and experiment persists. When we map the WCA model onto a hard-sphere system, we find good agreement between the present simulation results and those that had been obtained for hard spheres [L. Filion, M. Hermes, R. Ni, and M. Dijkstra, J. Chem. Phys. 133, 244115 (2010), 10.1063/1.3506838; S. Auer and D. Frenkel, Nature 409, 1020 (2001), 10.1038/35059035].

  18. Microgravity Emissions Laboratory Testing of the Physics of Colloids in Space Experiment

    NASA Astrophysics Data System (ADS)

    McNelis, Anne M.

    2002-01-01

    Microgravity Emissions Laboratory (MEL) in May of 2000 at NASA Glenn Research Center (GRC). PCS is a sub-rack payload that is accommodated in an EXPRESS-II rack on Space Station. This mission is the first flight of the Active Rack Isolation System - ISS Characterization Experiment (ARIS-ICE) on Station in the Express II rack. Fundamental PCS operation inertial responses were measured and are available for comparison to flight. Reported herein are the ground-based measurements for various PCS operations. capable of providing testing support for simulation and verification of the Space Station microgravity environment. MEL is capable of characterizing the operational emissions of components or rack-level disturbances. The inertial force output generated for the test article is utilized with FEA, SEA and other analysis tools to predict the on-orbit environment at specific interface or science region locations. GRC. Operations and Engineering Support are provided by the Technical Services Division at GRC.

  19. Topological colloids.

    PubMed

    Senyuk, Bohdan; Liu, Qingkun; He, Sailing; Kamien, Randall D; Kusner, Robert B; Lubensky, Tom C; Smalyukh, Ivan I

    2013-01-10

    Smoke, fog, jelly, paints, milk and shaving cream are common everyday examples of colloids, a type of soft matter consisting of tiny particles dispersed in chemically distinct host media. Being abundant in nature, colloids also find increasingly important applications in science and technology, ranging from direct probing of kinetics in crystals and glasses to fabrication of third-generation quantum-dot solar cells. Because naturally occurring colloids have a shape that is typically determined by minimization of interfacial tension (for example, during phase separation) or faceted crystal growth, their surfaces tend to have minimum-area spherical or topologically equivalent shapes such as prisms and irregular grains (all continuously deformable--homeomorphic--to spheres). Although toroidal DNA condensates and vesicles with different numbers of handles can exist and soft matter defects can be shaped as rings and knots, the role of particle topology in colloidal systems remains unexplored. Here we fabricate and study colloidal particles with different numbers of handles and genus g ranging from 1 to 5. When introduced into a nematic liquid crystal--a fluid made of rod-like molecules that spontaneously align along the so-called 'director'--these particles induce three-dimensional director fields and topological defects dictated by colloidal topology. Whereas electric fields, photothermal melting and laser tweezing cause transformations between configurations of particle-induced structures, three-dimensional nonlinear optical imaging reveals that topological charge is conserved and that the total charge of particle-induced defects always obeys predictions of the Gauss-Bonnet and Poincaré-Hopf index theorems. This allows us to establish and experimentally test the procedure for assignment and summation of topological charges in three-dimensional director fields. Our findings lay the groundwork for new applications of colloids and liquid crystals that range from

  20. Structure and interactions in fluids of prolate colloidal ellipsoids: comparison between experiment, theory, and simulation.

    PubMed

    Cohen, A P; Janai, E; Rapaport, D C; Schofield, A B; Sloutskin, E

    2012-11-14

    The microscopic structure of fluids of simple spheres is well known. However, the constituents of most real-life fluids are non-spherical, leading to a coupling between the rotational and translational degrees of freedom. The structure of simple dense fluids of spheroids - ellipsoids of revolution - was only recently determined by direct experimental techniques [A. P. Cohen, E. Janai, E. Mogilko, A. B. Schofield, and E. Sloutskin, Phys. Rev. Lett. 107, 238301 (2011)]. Using confocal microscopy, it was demonstrated that the structure of these simple fluids cannot be described by hard particle models based on the widely used Percus-Yevick approximation. In this paper, we describe a new protocol for determining the shape of the experimental spheroids, which allows us to expand our previous microscopy measurements of these fluids. To avoid the approximations in the theoretical approach, we have also used molecular dynamics simulations to reproduce the experimental radial distribution functions g(r) and estimate the contribution of charge effects to the interactions. Accounting for these charge effects within the Percus-Yevick framework leads to similar agreement with the experiment. PMID:23163381

  1. Viscosity of colloidal suspensions

    SciTech Connect

    Cohen, E.G.D.; Schepper, I.M. de

    1995-12-31

    Simple expressions are given for the effective Newtonian viscosity as a function of concentration as well as for the effective visco-elastic response as a function of concentration and imposed frequency, of monodisperse neutral colloidal suspensions over the entire fluid range. The basic physical mechanisms underlying these formulae are discussed. The agreement with existing experiments is very good.

  2. Advanced Smart Structures Flight Experiments for Precision Spacecraft

    NASA Astrophysics Data System (ADS)

    Denoyer, Keith K.; Erwin, R. Scott; Ninneman, R. Rory

    2000-07-01

    This paper presents an overview as well as data from four smart structures flight experiments directed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate in Albuquerque, New Mexico. The Middeck Active Control Experiment $¯Flight II (MACE II) is a space shuttle flight experiment designed to investigate modeling and control issues for achieving high precision pointing and vibration control of future spacecraft. The Advanced Controls Technology Experiment (ACTEX-I) is an experiment that has demonstrated active vibration suppression using smart composite structures with embedded piezoelectric sensors and actuators. The Satellite Ultraquiet Isolation Technology Experiment (SUITE) is an isolation platform that uses active piezoelectric actuators as well as damped mechanical flexures to achieve hybrid passive/active isolation. The Vibration Isolation, Suppression, and Steering Experiment (VISS) is another isolation platform that uses viscous dampers in conjunction with electromagnetic voice coil actuators to achieve isolation as well as a steering capability for an infra-red telescope.

  3. Americium, Cesium, and Plutonium Colloid-Facilitated Transport in a Groundwater/Bentonite/Fracture Fill Material System: Column Experiments and Model Results

    NASA Astrophysics Data System (ADS)

    Dittrich, T. M.; Boukhalfa, H.; Reimus, P. W.

    2014-12-01

    The objective of this study was to investigate and quantify the effects of desorption kinetics and colloid transport on radionuclides with different sorption affinities. We focused on quantifying transport mechanisms important for upscaling in time and distance. This will help determine the long-term fate and transport of radionuclides to aid in risk assessments. We selected a fractured/weathered granodiorite at the Grimsel Test Site (GTS) in Switzerland as a model crystalline rock repository system because the system has been thoroughly studied and field experiments involving radionuclides have already been conducted. Working on this system provides a unique opportunity to compare lab experiments with field-scale observations. Weathered fracture fill material (FFM) and bentonite used as backfill at the GTS were characterized (e.g., BET, SEM/EDS, QXRD), and batch and breakthrough column experiments were conducted. Solutions were prepared in synthetic groundwaters that matched the natural water chemistry. FFM samples were crushed, rinsed, sieved (150-355 μm), and equilibrated with synthetic groundwater. Bentonite was crushed, sodium-saturated, equilibrated with synthetic groundwater, and settled to yield a stable suspension. Suspensions were equilibrated with Am, Cs, or Pu. All experiments were conducted with Teflon®materials to limit sorption to system components. After radionuclide/colloid injections reached stability, radionuclide-free solutions were injected to observe the desorption and release behavior. Aliquots of effluent were measured for pH, colloid concentration, and total and dissolved radionuclides. Unanalyzed effluent from the first column was then injected through a second column of fresh material. The process was repeated for a third column and the results of all three breakthrough curves were modeled with a multi-site/multi-rate MATLAB code to elucidate the sorption rate coefficients and binding site densities of the bentonite colloids and

  4. Advanced Tokamak Plasmas in the Fusion Ignition Research Experiment

    SciTech Connect

    C.E. Kessel; D. Meade; D.W. Swain; P. Titus; M.A. Ulrickson

    2003-10-13

    The Advanced Tokamak (AT) capability of the Fusion Ignition Research Experiment (FIRE) burning plasma experiment is examined with 0-D systems analysis, equilibrium and ideal-MHD stability, radio-frequency current-drive analysis, and full discharge dynamic simulations. These analyses have identified the required parameters for attractive burning AT plasmas, and indicate that these are feasible within the engineering constraints of the device.

  5. Advanced gamma ray balloon experiment ground checkout and data analysis

    NASA Technical Reports Server (NTRS)

    Blackstone, M.

    1976-01-01

    A software programming package to be used in the ground checkout and handling of data from the advanced gamma ray balloon experiment is described. The Operator's Manual permits someone unfamiliar with the inner workings of the software system (called LEO) to operate on the experimental data as it comes from the Pulse Code Modulation interface, converting it to a form for later analysis, and monitoring the program of an experiment. A Programmer's Manual is included.

  6. Cavity Ring down Spectroscopy Experiment for an Advanced Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Stacewicz, T.; Wasylczyk, P.; Kowalczyk, P.; Semczuk, M.

    2007-01-01

    A simple experiment is described that permits advanced undergraduates to learn the principles and applications of the cavity ring down spectroscopy technique. The apparatus is used for measurements of low concentrations of NO[subscript 2] produced in air by an electric discharge. We present the setup, experimental procedure, data analysis and some…

  7. Advanced Undergraduate Laboratory Experiment in Inelastic Electron Tunneling Spectroscopy.

    ERIC Educational Resources Information Center

    White, H. W.; Graves, R. J.

    1982-01-01

    An advanced undergraduate laboratory experiment in inelastic electron tunneling spectroscopy is described. Tunnel junctions were fabricated, the tunneling spectra of several molecules absorbed on the surface of aluminum oxide measured, and mode assignments made for several of the prominent peaks in spectra using results obtained from optical…

  8. [Toxicological evaluation of nanosized colloidal silver, stabilized with polyvinylpyrrolidone, in 92-day experiment on rats. II. Internal organs morphology].

    PubMed

    Zaytseva, N V; Zemlyanova, M A; Zvezdin, V N; Dovbysh, A A; Gmoshinsky, I V; Khotimchenko, S A; Akafieva, T I

    2016-01-01

    The aim of the study was to evaluate the safe doses of commercially available nanosized colloidal silver (NCS), stabilized with polyvinilpirrolidone (PVP, food additive E1201) when administered in gastrointestinal tract of rats in the 92-day experiment in terms of the morphological changes in the internals of animals. The sample studied contained non-aggregated nanoparticles (NPs) of silver belonging to size fractions with a diameter of less than 5 nm, 10-20 nm or 50-80 nm. 80% of NPs were inside the range of hydrodynamic diameters 10.6-61.8 nm. The preparation of NCS was administered to growing male Wistar rats. (initial body weight 80 ± 10 g) for 1 month by intragastric gavage and then consumed with food at doses of 0.1, 1.0 and 10 mg/kg of body weight based on silver. The control animals received water or vehicle of nanomaterial--water solution of PVP. After withdrawal of animals from the experiment by exsanguination under ether anesthesia organs (liver, spleen, kidney, ileum) were isolated and their slides were prepared by standard methods following 'by staining with hematoxylin-eosin. Analysis was performed in light optical microscope equipped with a digital camera at a magnification from 1 x 100 to 1 x 1000. It was shown that the experimental animals treated with the NCS developed series of morphological changes in the tissues of the internal organs (liver, spleen and kidney) with the elevation of the range and severity of structural changes with increasing doses of silver. The most sensitive target of NCS action was apparently liver, which has already shown at a dose of 0.1 mg of silver NP/kg of body weight marked eosinophilic infiltration of portal tracts, which was accompanied at doses of 1.0 and 10.0 mg/kg by the emergence of medium and large-drop fat vacuoles in the cytoplasm of hepatocytes, swelling and lympho-macrophage. infiltration of the portal tracts. Detectable changes can be regarded as symptoms of inflammation of hepatocytes, at least, at a

  9. Advanced Experiments in Nuclear Science, Volume I: Advanced Nuclear Physics and Chemistry Experiments.

    ERIC Educational Resources Information Center

    Duggan, Jerome L.; And Others

    The experiments in this manual represent state-of-the-art techniques which should be within the budgetary constraints of a college physics or chemistry department. There are fourteen experiments divided into five modules. The modules are on X-ray fluorescence, charged particle detection, neutron activation analysis, X-ray attenuation, and…

  10. Colloidal polyaniline

    DOEpatents

    Armes, Steven P.; Aldissi, Mahmoud

    1990-01-01

    Processable electrically conductive latex polymer compositions including colloidal particles of an oxidized, polymerized amino-substituted aromatic monomer, a stabilizing effective amount of a random copolymer containing amino-benzene type moieties as side chain constituents, and dopant anions, and a method of preparing such polymer compositions are provided.

  11. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  12. Simulator design for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerald R.

    1992-01-01

    This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) program, moves all control and switching functions on-board the next generation ISDN communication satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete events simulation experiments will be performed with these models using various traffic scenarios, design parameters and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  13. Emergent behavior in active colloids

    NASA Astrophysics Data System (ADS)

    Zöttl, Andreas; Stark, Holger

    2016-06-01

    Active colloids are microscopic particles, which self-propel through viscous fluids by converting energy extracted from their environment into directed motion. We first explain how artificial microswimmers move forward by generating near-surface flow fields via self-phoresis or the self-induced Marangoni effect. We then discuss generic features of the dynamics of single active colloids in bulk and in confinement, as well as in the presence of gravity, field gradients, and fluid flow. In the third section, we review the emergent collective behavior of active colloidal suspensions, focusing on their structural and dynamic properties. After summarizing experimental observations, we give an overview of the progress in modeling collectively moving active colloids. While active Brownian particles are heavily used to study collective dynamics on large scales, more advanced methods are necessary to explore the importance of hydrodynamic and phoretic particle interactions. Finally, the relevant physical approaches to quantify the emergent collective behavior are presented.

  14. Explosive Vessel for Dynamic Experiments at Advanced Light Sources

    NASA Astrophysics Data System (ADS)

    Owens, Charles; Sorensen, Christian; Armstrong, Christopher; Sanchez, Nathaniel; Jensen, Brian

    2015-06-01

    There has been significant effort in coupling dynamic loading platforms to advanced light sources such as the Advanced Photon Source (APS) to take advantage of X-ray diagnostics for examining material physics at extremes. Although the focus of these efforts has been on using gun systems for dynamic compression experiments, there are many experiments that require explosive loading capabilities including studies related to detonator dynamics, small angle X-ray scattering on explosives, and ejecta formation, for example. To this end, an explosive vessel and positioning stage was designed specifically for use at a synchrotron with requirements to confine up to 15 grams of explosives, couple the vessel to the X-ray beam line, and reliably position samples in the X-ray beam remotely with micrometer spatial accuracy. In this work, a description of the system will be provided along with explosive testing results for the robust, reusable positioning system.

  15. Advances in Experiment Design for High Performance Aircraft

    NASA Technical Reports Server (NTRS)

    Morelli, Engene A.

    1998-01-01

    A general overview and summary of recent advances in experiment design for high performance aircraft is presented, along with results from flight tests. General theoretical background is included, with some discussion of various approaches to maneuver design. Flight test examples from the F-18 High Alpha Research Vehicle (HARV) are used to illustrate applications of the theory. Input forms are compared using Cramer-Rao bounds for the standard errors of estimated model parameters. Directions for future research in experiment design for high performance aircraft are identified.

  16. Preliminary results from the advanced photovoltaic experiment flight test

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hart, Russell E., Jr.; Hickey, John R.

    1990-01-01

    The Advanced Photovoltaic Experiment is a space flight test designed to provide reference cell standards for photovoltaic measurement as well as to investigate the solar spectrum and the effect of the space environment on solar cells. After a flight of 69 months in low earth orbit as part of the Long Duration Exposure Facility set of experiments, it was retrieved in January, 1990. The electronic data acquisition system functioned as designed, measuring and recording cell performance data over the first 358 days of flight; limited by battery lifetime. Significant physical changes are also readily apparent, including erosion of front surface paint, micrometeoroid and debris catering and contamination.

  17. Colloid particle size-dependent dispersivity

    NASA Astrophysics Data System (ADS)

    Chrysikopoulos, C. V.; Katzourakis, V. E.

    2014-12-01

    Laboratory and field studies have demonstrated that dispersion coefficients evaluated by fitting advection-dispersion transport models to nonreactive tracer breakthrough curves do not adequately describe colloid transport under the same flow field conditions. Here an extensive laboratory study was undertaken to assess whether the dispersivity, which traditionally has been considered to be a property of the porous medium, is dependent on colloid particle size and interstitial velocity. A total of 49 colloid transport experiments were performed in columns packed with glass beads under chemically unfavorable colloid attachment conditions. Nine different colloid diameters, and various flow velocities were examined. The breakthrough curves were successfully simulated with a mathematical model describing colloid transport in homogeneous, water saturated porous media. The results demonstrated that the dispersivity is positively correlated with colloid particle size, and increases with increasing velocity.

  18. Cytosolic delivery of materials with endosome-disrupting colloids

    DOEpatents

    Helms, Brett A.; Bayles, Andrea R.

    2016-03-15

    A facile procedure to deliver nanocrystals to the cytosol of live cells that is both rapid and general. The technique employs a unique cationic core-shell polymer colloid that directs nanocrystals to the cytosol of living cells within a few hours of incubation. The present methods and compositions enable a host of advanced applications arising from efficient cytosolic delivery of nanocrystal imaging probes: from single particle tracking experiments to monitoring protein-protein interactions in live cells for extended periods.

  19. Colloidal Double Quantum Dots

    PubMed Central

    2016-01-01

    Conspectus Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single

  20. Colloidal Double Quantum Dots.

    PubMed

    Teitelboim, Ayelet; Meir, Noga; Kazes, Miri; Oron, Dan

    2016-05-17

    Pairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots. The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole-dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs). One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon

  1. The unbearable heaviness of colloids: facts, surprises, and puzzles in sedimentation

    NASA Astrophysics Data System (ADS)

    Piazza, Roberto; Buzzaccaro, Stefano; Secchi, Eleonora

    2012-07-01

    Sedimentation has played a key role in the development of colloid science. In fact, it is because of the celebrated experiments by Perrin, yielding a concrete demonstration of molecular reality and giving strong support to Einstein’s theory of Brownian motion, that colloids enter the realm of basic physics. Subsequent investigations have shown that a lot more can be learnt both from sedimentation equilibrium and from particle settling dynamics. These advances, together with new experimental approaches, will be reviewed in this paper. Yet, we shall also show that inquiring about gravity settling is far from being a closed matter: for instance, the concept of buoyancy for a settling colloidal mixture is far from being obvious. Moreover, sedimentation holds novel surprises, such as colloidal inflations and settling disasters, showing that a simple external field like gravity may induce mind-boggling, and theoretically challenging effects.

  2. Binary Colloidal Alloy Test Conducted on Mir

    NASA Technical Reports Server (NTRS)

    Hoffmann, Monica I.; Ansari, Rafat R.

    1999-01-01

    Colloids are tiny (submicron) particles suspended in fluid. Paint, ink, and milk are examples of colloids found in everyday life. The Binary Colloidal Alloy Test (BCAT) is part of an extensive series of experiments planned to investigate the fundamental properties of colloids so that scientists can make colloids more useful for technological applications. Some of the colloids studied in BCAT are made of two different sized particles (binary colloidal alloys) that are very tiny, uniform plastic spheres. Under the proper conditions, these colloids can arrange themselves in a pattern to form crystals. These crystals may form the basis of new classes of light switches, displays, and optical devices. Windows made of liquid crystals are already in the marketplace. These windows change their appearance from transparent to opaque when a weak electric current is applied. In the future, if the colloidal crystals can be made to control the passage of light through them, such products could be made much more cheaply. These experiments require the microgravity environment of space because good quality crystals are difficult to produce on Earth because of sedimentation and convection in the fluid. The BCAT experiment hardware included two separate modules for two different experiments. The "Slow Growth" hardware consisted of a 35-mm camera with a 250- exposure photo film cartridge. The camera was aimed toward the sample module, which contained 10 separate colloid samples. A rack of small lights provided backlighting for the photographs. The BCAT hardware was launched on the shuttle and was operated aboard the Russian space station Mir by American astronauts John Blaha and David Wolf (launched September 1996 and returned January 1997; reflown September 1997 and returned January 1998). To begin the experiment, one of these astronauts would mix the samples to disperse the colloidal particles and break up any crystals that might have already formed. Once the samples were mixed and

  3. Experiments applications guide: Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This applications guide first surveys the capabilities of the Advanced Communication Technology Satellite (ACTS) system (both the flight and ground segments). This overview is followed by a description of the baseband processor (BBP) and microwave switch matrix (MSM) operating modes. Terminals operating with the baseband processor are referred to as low burst rate (LBR); and those operating with the microwave switch matrix, as high burst rate (HBR). Three very small-aperture terminals (VSATs), LBR-1, LBR-2, and HBR, are described for various ACTS operating modes. Also described is the NASA Lewis link evaluation terminal. A section on ACTS experiment opportunities introduces a wide spectrum of network control, telecommunications, system, and scientific experiments. The performance of the VSATs is discussed in detail. This guide is intended as a catalyst to encourage participation by the telecommunications, business, and science communities in a broad spectrum of experiments.

  4. Soil colloidal behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent understanding that organic and inorganic contaminants are often transported via colloidal particles has increased interest in colloid science. The primary importance of colloids in soil science stems from their surface reactivity and charge characteristics. Characterizations of size, shape,...

  5. Space station experiment definition: Advanced power system test bed

    NASA Technical Reports Server (NTRS)

    Pollard, H. E.; Neff, R. E.

    1986-01-01

    A conceptual design for an advanced photovoltaic power system test bed was provided and the requirements for advanced photovoltaic power system experiments better defined. Results of this study will be used in the design efforts conducted in phase B and phase C/D of the space station program so that the test bed capabilities will be responsive to user needs. Critical PV and energy storage technologies were identified and inputs were received from the idustry (government and commercial, U.S. and international) which identified experimental requirements. These inputs were used to develop a number of different conceptual designs. Pros and cons of each were discussed and a strawman candidate identified. A preliminary evolutionary plan, which included necessary precursor activities, was established and cost estimates presented which would allow for a successful implementation to the space station in the 1994 time frame.

  6. Design of the Advanced Gas Reactor Fuel Experiments for Irradiation in the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover

    2005-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight particle fuel tests in the Advanced Test Reactor (ATR) located at the newly formed Idaho National Laboratory (INL) to support development of the next generation Very High Temperature Reactor (VHTR) in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments will be irradiated in an inert sweep gas atmosphere with on-line temperature monitoring and control combined with on-line fission product monitoring of the sweep gas. The final design phase has just been completed on the first experiment (AGR-1) in this series and the support systems and fission product monitoring system that will monitor and control the experiment during irradiation. This paper discusses the development of the experimental hardware and support system designs and the status of the experiment.

  7. Advanced experiments with an erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Marques, Paulo V. S.; Marques, Manuel B.; Rosa, Carla C.

    2014-07-01

    This communication describes an optical hands-on fiber laser experiment aimed at advanced college courses. Optical amplifiers and laser sources represent very important optical devices in numerous applications ranging from telecommunications to medicine. The study of advanced photonics experiments is particularly relevant at undergraduate and master level. This paper discusses the implementation of an optical fiber laser made with a cavity built with two tunable Bragg gratings. This scheme allows the students to understand the laser working principles as a function of the laser cavity set-up. One or both of the gratings can be finely tuned in wavelength through applied stress; therefore, the degree of spectral mismatch of the two gratings can be adjusted, effectively changing the cavity feedback. The impact of the cavity conditions on the laser threshold, spectrum and efficiency is analyzed. This experiment assumes that in a previous practice, the students should had already characterized the erbium doped fiber in terms of absorption and fluorescent spectra, and the spectral gain as a function of pump power.

  8. Advanced Gas Reactor (AGR)-5/6/7 Fuel Irradiation Experiments in the Advanced Test Reactor

    SciTech Connect

    A. Joseph Palmer; David A. Petti; S. Blaine Grover

    2014-04-01

    The United States Department of Energy’s Very High Temperature Reactor (VHTR) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which each consist of at least five separate capsules, are being irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gases also have on-line fission product monitoring the effluent from each capsule to track performance of the fuel during irradiation. The first two experiments (designated AGR-1 and AGR-2), have been completed. The third and fourth experiments have been combined into a single experiment designated AGR-3/4, which started its irradiation in December 2011 and is currently scheduled to be completed in April 2014. The design of the fuel qualification experiment, designated AGR-5/6/7, is well underway and incorporates lessons learned from the three previous experiments. Various design issues will be discussed with particular details related to selection of thermometry.

  9. Enhancing the Detector for Advanced Neutron Capture Experiments

    NASA Astrophysics Data System (ADS)

    Couture, A.; Mosby, S.; Baramsai, B.; Bredeweg, T. A.; Jandel, M.; Macon, K.; O'Donnell, J. M.; Rusev, G.; Taddeucci, T. N.; Ullmann, J. L.; Walker, C. L.

    2015-05-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) has been used for extensive studies of neutron capture, gamma decay, photon strength functions, and prompt and delayed fission-gamma emission. Despite these successes, the potential measurements have been limited by the data acquisition hardware. We report on a major upgrade of the DANCE data acquisition that simultaneously enables strait-forward coupling to auxiliary detectors, including high-resolution high-purity germanium detectors and neutron tagging array. The upgrade will enhance the time domain accessible for time-of-flight neutron measurements as well as improve the resolution in the DANCE barium fluoride crystals for photons.

  10. Enhancing the detector for advanced neutron capture experiments

    DOE PAGESBeta

    Couture, A.; Mosby, S.; Baramsai, B.; Bredeweg, T. A.; Jandel, M.; Macon, K.; O’Donnell, J. M.; Rusev, G.; Taddeucci, T. N; Ullmann, J. L.; et al

    2015-05-28

    The Detector for Advanced Neutron Capture Experiments (DANCE) has been used for extensive studies of neutron capture, gamma decay, photon strength functions, and prompt and delayed fission-gamma emission. Despite these successes, the potential measurements have been limited by the data acquisition hardware. We report on a major upgrade of the DANCE data acquisition that simultaneously enables strait-forward coupling to auxiliary detectors, including high-resolution high-purity germanium detectors and neutron tagging array. The upgrade will enhance the time domain accessible for time-of-flight neutron measurements as well as improve the resolution in the DANCE barium fluoride crystals for photons.

  11. Detector for advanced neutron capture experiments at LANSCE

    SciTech Connect

    Ullmann, J. L.; Reifarth, R.; Haight, Robert C.; Hunt, L. F.; O'Donnell, J. M.; Bredeweg, T. A.; Wilhelmy, J. B.; Fowler, Malcolm M.; Vieira, D. J.; Wouters, J. M.; Strottman, D.; Kaeppeler, F.; Heil, M.; Chamberlin, E. P.

    2002-01-01

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 159-element 4x barium fluoride array designed to study neutron capture on small quantities, 1 mg or less, of radioactive nuclides. It is being built on a 20 m neutron flight path which views the 'upper tier' water moderator at the Manuel J. Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center. The detector design is based on Monte Carlo calculations which have suggested ways to minimize backgrounds due to neutron scattering events. A data acquisition system based on fast transient digitizers is bcing implemented

  12. The Detector for Advanced Neutron Capture Experiments at LANSCE

    SciTech Connect

    Ullmann, J.L.; Reifarth, R.; Haight, R.C.; Hunt, L.; O'Donnell, J.M.; Rundberg, R.S.; Bredeweg, T.A.; Wilhelmy, J.B.; Fowler, M.M.; Vieira, D.J.; Wouters, J.M.; Strottman, D.D.; Kaeppeler, F.; Heil, M.; Chamberlin, E.P.

    2003-08-26

    The Detector for Advanced Neutron Capture Experiments (DANCE) is a 159-element 4{pi} barium fluoride array designed to study neutron capture on small quantities, 1 mg or less, of radioactive nuclides. It is being built on a 20 m neutron flight path which views the 'upper tier' water moderator at the Manuel J. Lujan Jr. Neutron Scattering Center at the Los Alamos Neutron Science Center. The detector design is based on Monte Carlo calculations which have suggested ways to minimize backgrounds due to neutron scattering events. A data acquisition system based on fast transient digitizers is being implemented.

  13. Advanced Test Reactor Testing Experience: Past, Present and Future

    SciTech Connect

    Frances M. Marshall

    2005-04-01

    The Advanced Test Reactor (ATR), at the Idaho National Laboratory (INL), is one of the world’s premier test reactors for providing the capability for studying the effects of intense neutron and gamma radiation on reactor materials and fuels. The physical configuration of the ATR, a 4-leaf clover shape, allows the reactor to be operated at different power levels in the corner “lobes” to allow for different testing conditions for multiple simultaneous experiments. The combination of high flux (maximum thermal neutron fluxes of 1E15 neutrons per square centimeter per second and maximum fast [E>1.0 MeV] neutron fluxes of 5E14 neutrons per square centimeter per second) and large test volumes (up to 48" long and 5.0" diameter) provide unique testing opportunities. The current experiments in the ATR are for a variety of test sponsors -- US government, foreign governments, private researchers, and commercial companies needing neutron irradiation services. There are three basic types of test configurations in the ATR. The simplest configuration is the sealed static capsule, wherein the target material is placed in a capsule, or plate form, and the capsule is in direct contact with the primary coolant. The next level of complexity of an experiment is an instrumented lead experiment, which allows for active monitoring and control of experiment conditions during the irradiation. The highest level of complexity of experiment is the pressurized water loop experiment, in which the test sample can be subjected to the exact environment of a pressurized water reactor. For future research, some ATR modifications and enhancements are currently planned. This paper provides more details on some of the ATR capabilities, key design features, experiments, and future plans.

  14. Interhemispheric transcallosal transforaminal approach and its variants to colloid cyst of third ventricle: Technical issues based on a single institutional experience of 297 cases

    PubMed Central

    Nair, Suresh; Gopalakrishnan, C. V.; Menon, Girish; Easwer, H. V.; Abraham, Mathew

    2016-01-01

    Context: Colloid cysts are benign intracranial lesions that usually involve the anterior third ventricle with varying appearance on imaging studies. The number of articles debating the origin of this tumor is surpassed by papers proposing the best modality available for its treatment Aim: The purpose of this study is to analyze the clinical presentation and surgical outcome of colloid cysts surgically managed over a period of thirty-two years and evaluate the technical issues based on our experience. Study Design: This is a retrospective case series study. Materials and Methods: This is a retrospective case series study on 297 consecutive patients with colloid cysts who were operated. The case records of all the patients were evaluated to record the clinical symptoms and signs, imaging findings, surgical procedure, complications and follow-up data. Results: There were 178 (60%) males and 119 (40%) females, their age ranging from 9 to 66 years with a mean age of 28 years. The mean duration of symptoms was 1.8 months. Raised intracranial pressure headache was the most common initial presenting symptom followed by visual blurring, memory disturbance and drop attacks with gait unsteadiness. The tumor was an incidental imaging finding in five patients (2%). While an interhemispheric transcallosal approach was used in 275 (92.6%) patients, it was trans-cortical in 22 (7.4%). Twenty-two patients required emergency surgery in view of worsening sensorium. Postoperative complications included memory impairment, limb weakness and seizures. Despite documented complete excision of the tumor in 6 cases, 8 patients had recurrence of tumor during follow-up. Conclusion: Colloid cysts are potential life threatening but benign lesions that can be removed safely with low morbidity and mortality through the interhemispheric transcallosal approach and its variants. The possibility for recurrence warrants, close imaging follow-up after surgery. It is essential for neurosurgeons to be

  15. Experiences of the advanced nurse practitioner role in acute care.

    PubMed

    Cowley, Alison; Cooper, Joanne; Goldberg, Sarah

    2016-05-01

    The aim of the service evaluation presented in this article was to explore the multidisciplinary team's (MDT) experiences and perception of the advanced nurse practitioner (ANP) role on an acute health care of the older person ward. A qualitative case study was carried out comprising semi-structured interviews with members of the MDT, exploring their experiences of the ANP role. An overarching theme of 'Is it a nurse? Is it a doctor? No, it's an ANP' emerged from the data, with three subthemes: the missing link; facilitating and leading holistic care; and safe, high quality care. The ANP role is valued by the MDT working with them and provides a unique skill set that has the potential to enhance care of older patients living with frailty. While there are challenges to its introduction, it is a role worth introducing to older people's wards. PMID:27125941

  16. Mobile antennas for COMETS advanced mobile Satcom experiment

    NASA Technical Reports Server (NTRS)

    Hase, Yoshihiro; Tanaka, Masato; Saito, Haruo

    1995-01-01

    Advanced mobile satellite communication experiments in the Ka-band and the mm-wave will be carried out using the COMETS satellite, which is scheduled for launch in 1997. Mobile antennas will play a much more key role in high frequency systems such as COMETS than in conventional L-band mobile systems. This paper describes three types of antennas which are now being developed by the Communications Research Laboratory (CRL) for the COMETS mobile experiments. One is a mechanically steered waveguide slot array antenna, another is an electronically steered active phased array antenna, and the third is a mechanically steered torus reflector antenna. The first two antennas will be used in the Ka-band, while the latter will be used in the mm-wave.

  17. Advances in shock timing experiments on the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Celliers, P. M.; Moody, J. D.; Sater, J.; Parham, T.; Kozioziemski, B.; Dylla-Spears, R.; Ross, J. S.; LePape, S.; Ralph, J. E.; Hohenberger, M.; Dewald, E. L.; Berzak Hopkins, L.; Kroll, J. J.; Yoxall, B. E.; Hamza, A. V.; Boehly, T. R.; Nikroo, A.; Landen, O. L.; Edwards, M. J.

    2016-03-01

    Recent advances in shock timing experiments and analysis techniques now enable shock measurements to be performed in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility (NIF). Previous measurements of shock timing in inertial confinement fusion (ICF) implosions were performed in surrogate targets, where the solid DT ice shell and central DT gas were replaced with a continuous liquid deuterium (D2) fill. These previous experiments pose two surrogacy issues: a material surrogacy due to the difference of species (D2 vs. DT) and densities of the materials used and a geometric surrogacy due to presence of an additional interface (ice/gas) previously absent in the liquid-filled targets. This report presents experimental data and a new analysis method for validating the assumptions underlying this surrogate technique.

  18. Partner for Promotion: An Innovative Advanced Community Pharmacy Practice Experience

    PubMed Central

    Legg, Julie E.; Casper, Kristin A.

    2008-01-01

    Objectives To implement the Partner for Promotion (PFP) program which was designed to enhance the skills and confidence of students and community pharmacy preceptors to deliver and expand advanced patient care services in community pharmacies and also to assess the program's impact. Design A 10-month longitudinal community advanced pharmacy practice experience was implemented that included faculty mentoring of students and preceptors via formal orientation; face-to-face training sessions; online monthly meetings; feedback on service development materials; and a web site offering resources and a discussion board. Pre- and post-APPE surveys of students and preceptors were used to evaluate perceptions of knowledge and skills. Assessment The skills survey results for the first 2 years of the PFP program suggest positive changes occurring from pre- to post-APPE survey in most areas for both students and preceptors. Four of the 7 pharmacies in 2005-2006 and 8 of the 14 pharmacies in 2006-2007 were able to develop an advanced patient care service and begin seeing patients prior to the conclusion of the APPE. As a result of the PFP program from 2005-2007, 14 new experiential sites entered into affiliation agreements with The Ohio State University College of Pharmacy. Conclusion The PFP program offers an innovative method for community pharmacy faculty members to work with students and preceptors in community pharmacies in developing patient care services. PMID:19325954

  19. Unification of dynamic density functional theory for colloidal fluids to include inertia and hydrodynamic interactions: derivation and numerical experiments.

    PubMed

    Goddard, B D; Nold, A; Savva, N; Yatsyshin, P; Kalliadasis, S

    2013-01-23

    Starting from the Kramers equation for the phase-space dynamics of the N-body probability distribution, we derive a dynamical density functional theory (DDFT) for colloidal fluids including the effects of inertia and hydrodynamic interactions (HI). We compare the resulting theory to extensive Langevin dynamics simulations for both hard rod systems and three-dimensional hard sphere systems with radially symmetric external potentials. As well as demonstrating the accuracy of the new DDFT, by comparing with previous DDFTs which neglect inertia, HI, or both, we also scrutinize the significance of including these effects. Close to local equilibrium we derive a continuum equation from the microscopic dynamics which is a generalized Navier-Stokes-like equation with additional non-local terms governing the effects of HI. For the overdamped limit we recover analogues of existing configuration-space DDFTs but with a novel diffusion tensor. PMID:23220969

  20. An evaluation of adhesive sample holders for advanced crystallographic experiments

    SciTech Connect

    Mazzorana, Marco; Sanchez-Weatherby, Juan Sandy, James; Lobley, Carina M. C.; Sorensen, Thomas

    2014-09-01

    Commercially available adhesives have been evaluated for crystal mounting when undertaking complex macromolecular crystallography experiments. Here, their use as tools for advanced sample mounting and cryoprotection is assessed and their suitability for room-temperature data-collection and humidity-controlled studies is investigated. The hydration state of macromolecular crystals often affects their overall order and, ultimately, the quality of the X-ray diffraction pattern that they produce. Post-crystallization techniques that alter the solvent content of a crystal may induce rearrangement within the three-dimensional array making up the crystal, possibly resulting in more ordered packing. The hydration state of a crystal can be manipulated by exposing it to a stream of air at controlled relative humidity in which the crystal can equilibrate. This approach provides a way of exploring crystal hydration space to assess the diffraction capabilities of existing crystals. A key requirement of these experiments is to expose the crystal directly to the dehydrating environment by having the minimum amount of residual mother liquor around it. This is usually achieved by placing the crystal on a flat porous support (Kapton mesh) and removing excess liquid by wicking. Here, an alternative approach is considered whereby crystals are harvested using adhesives that capture naked crystals directly from their crystallization drop, reducing the process to a one-step procedure. The impact of using adhesives to ease the harvesting of different types of crystals is presented together with their contribution to background scattering and their usefulness in dehydration experiments. It is concluded that adhesive supports represent a valuable tool for mounting macromolecular crystals to be used in humidity-controlled experiments and to improve signal-to-noise ratios in diffraction experiments, and how they can protect crystals from modifications in the sample environment is discussed.

  1. Colloidal entanglement in highly twisted chiral nematic colloids: twisted loops, Hopf links, and trefoil knots.

    PubMed

    Jampani, V S R; Škarabot, M; Ravnik, M; Čopar, S; Žumer, S; Muševič, I

    2011-09-01

    The topology and geometry of closed defect loops is studied in chiral nematic colloids with variable chirality. The colloidal particles with perpendicular surface anchoring of liquid crystalline molecules are inserted in a twisted nematic cell with the thickness that is only slightly larger than the diameter of the colloidal particle. The total twist of the chiral nematic structure in cells with parallel boundary conditions is set to 0, π, 2π, and 3π, respectively. We use the laser tweezers to discern the number and the topology of the -1/2 defect loops entangling colloidal particles. For a single colloidal particle, we observe that a single defect loop is winding around the particle, with the winding pattern being more complex in cells with higher total twist. We observe that colloidal dimers and colloidal clusters are always entangled by one or several -1/2 defect loops. For colloidal pairs in π-twisted cells, we identify at least 17 different entangled structures, some of them exhibiting linked defect loops-Hopf link. Colloidal entanglement is even richer with a higher number of colloidal particles, where we observe not only linked, but also colloidal clusters knotted into the trefoil knot. The experiments are in good agreement with numerical modeling using Landau-de Gennes theory coupled with geometrical and topological considerations using the method of tetrahedral rotation. PMID:22060386

  2. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    NASA Astrophysics Data System (ADS)

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-09-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields.

  3. Simulated Interactive Research Experiments as Educational Tools for Advanced Science.

    PubMed

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  4. Simulated Interactive Research Experiments as Educational Tools for Advanced Science

    PubMed Central

    Tomandl, Mathias; Mieling, Thomas; Losert-Valiente Kroon, Christiane M.; Hopf, Martin; Arndt, Markus

    2015-01-01

    Experimental research has become complex and thus a challenge to science education. Only very few students can typically be trained on advanced scientific equipment. It is therefore important to find new tools that allow all students to acquire laboratory skills individually and independent of where they are located. In a design-based research process we have investigated the feasibility of using a virtual laboratory as a photo-realistic and scientifically valid representation of advanced scientific infrastructure to teach modern experimental science, here, molecular quantum optics. We found a concept based on three educational principles that allows undergraduate students to become acquainted with procedures and concepts of a modern research field. We find a significant increase in student understanding using our Simulated Interactive Research Experiment (SiReX), by evaluating the learning outcomes with semi-structured interviews in a pre/post design. This suggests that this concept of an educational tool can be generalized to disseminate findings in other fields. PMID:26370627

  5. Advanced solar panel concentrator experiment (ASPaCE)

    SciTech Connect

    Whalen, B.P.

    1997-12-31

    The US Naval Research Laboratory (NRL) is beginning Phase 2 development for the Advanced Solar Panel Concentrator Experiment (ASPaCE). Phase 1 showed that flexible thin film reflectors can work successfully in a deployable trough concentrator. Thin film reflectors add several advantages to this concentrator including compact stowage, increase power from conventional fold-out solar panels, and solar cell exposure during orbit transfer. Testing on a proof-of-concept model has been completed (Phase 1) and correlation to a large scale flight model is under way. In Phase 2 a large scale reflector on the order of 6 meters by 2.5 meters is being built for deployment and deformation testing and a flight quality array is being designed.

  6. Plan of advanced satellite communications experiment using ETS-VI

    NASA Technical Reports Server (NTRS)

    Shiomi, Tadashi

    1988-01-01

    Communications Research Laboratory (CRL, Ministry of Posts and Telecommunications, Japan) has been engaged in development of three advanced satellite communication payloads aiming at experiments by Japan's 2-ton class Engineering Test Satellite VI (ETS-VI) which is to be launched in H-II rocket by NASDA in August 1992. CRL's three experimental systems are: (1) S-band inter-satellite communications; (2) millimeter-wave inter-satellite and personal-satellite communications; and (3) optical inter-satellite communications. CRL develops experimental optical communication system with telescope of 75 mm diameter which has gimbal mirror beam pointing/tracking mechanism. The onboard system has fundamental optical communication functions with laser diode transmitter of wavelength 0.83 micron, laser beam point-ahead mechanism, receiver of wavelength 0.51 micron, modulation/demodulation subsystem, and so on.

  7. Binary Colloidal Alloy Test-5: Aspheres

    NASA Technical Reports Server (NTRS)

    Chaikin, Paul M.; Hollingsworth, Andrew D.

    2008-01-01

    The Binary Colloidal Alloy Test - 5: Aspheres (BCAT-5-Aspheres) experiment photographs initially randomized colloidal samples (tiny nanoscale spheres suspended in liquid) in microgravity to determine their resulting structure over time. BCAT-5-Aspheres will study the properties of concentrated systems of small particles when they are identical, but not spherical in microgravity..

  8. Entropy favours open colloidal lattices

    NASA Astrophysics Data System (ADS)

    Mao, Xiaoming; Chen, Qian; Granick, Steve

    2013-03-01

    Burgeoning experimental and simulation activity seeks to understand the existence of self-assembled colloidal structures that are not close-packed. Here we describe an analytical theory based on lattice dynamics and supported by experiments that reveals the fundamental role entropy can play in stabilizing open lattices. The entropy we consider is associated with the rotational and vibrational modes unique to colloids interacting through extended attractive patches. The theory makes predictions of the implied temperature, pressure and patch-size dependence of the phase diagram of open and close-packed structures. More generally, it provides guidance for the conditions at which targeted patchy colloidal assemblies in two and three dimensions are stable, thus overcoming the difficulty in exploring by experiment or simulation the full range of conceivable parameters.

  9. Intermittent filtration of bacteria and colloids in porous media

    NASA Astrophysics Data System (ADS)

    Auset, Maria; Keller, Arturo A.; Brissaud, FrançOis; Lazarova, Valentina

    2005-09-01

    Intermittent filtration through porous media used for water and wastewater treatment can achieve high pathogen and colloid removal efficiencies. To predict the removal of bacteria, the effects of cyclic infiltration and draining events (transient unsaturated flow) were investigated. Using physical micromodels, we visualized the intermittent transport of bacteria and other colloids in unsaturated porous media. Column experiments provided quantitative measurements of the phenomena observed at the pore scale. Tagged Escherichia coli and a conservative tracer (NaI) were introduced in an initial pulse into a 1.5 m sand column. Subsequent hydraulic flushes without tagged bacteria or tracer were repeated every 4 hours for the next 4 days, during which outflow concentrations were monitored. Breakthrough behavior between colloids and dissolved tracer differed significantly, reflecting the differences in transport processes. Advancement of the wetting front remobilized bacteria which were held in thin water films, attached to the air-water interface (AWI), or entrapped in stagnant pore water between gas bubbles. In contrast, the tracer was only remobilized by diffusion from immobile to mobile water. Remobilization led to successive concentration peaks of bacteria and tracer in the effluent but with significant temporal differences. Observations at the pore-scale indicated that the colloids were essentially irreversibly attached to the solid-water interface, which explained to some extent the high removal efficiency of microbes in the porous media. Straining, cluster filtration, cell lysis, protozoa grazing, and bacteriophage parasitism could also contribute to the removal efficiency of bacteria.

  10. Influence of heteroaggregation processes between intrinsic colloids and carrier colloids on cerium(III) mobility through fractured carbonate rocks.

    PubMed

    Tran, Emily; Klein Ben-David, Ofra; Teutch, Nadya; Weisbrod, Noam

    2016-09-01

    Colloid facilitated transport of radionuclides has been implicated as a major transport vector for leaked nuclear waste in the subsurface. Sorption of radionuclides onto mobile carrier colloids such as bentonite and humic acid often accelerates their transport through saturated rock fractures. Here, we employ column studies to investigate the impact of intrinsic, bentonite and humic acid colloids on the transport and recovery of Ce(III) through a fractured chalk core. Ce(III) recovery where either bentonite or humic colloids were added was 7.7-26.9% Ce for all experiments. Greater Ce(III) recovery was observed when both types of carrier colloids were present (25.4-37.4%). When only bentonite colloids were present, Ce(III) appeared to be fractionated between chemical sorption to the bentonite colloid surfaces and heteroaggregation of bentonite colloids with intrinsic carbonate colloids, precipitated naturally in solution. However, scanning electron microscope (SEM) images and colloid stability experiments reveal that in suspensions of humic acid colloids, colloid-facilitated Ce(III) migration results only from the latter attachment mechanism rather than from chemical sorption. This observed heteroaggregation of different colloid types may be an important factor to consider when predicting potential mobility of leaked radionuclides from geological repositories for spent fuel located in carbonate rocks. PMID:27183207

  11. Canadian Advanced Nanospace Experiment 2: Om-Orbit Experience with an Innovative Three-Kilogram Satellite

    NASA Astrophysics Data System (ADS)

    Sarda, K.; Grant, C.; Eagleson, S.; Kekez, D. D.; Zee, R. E.

    2008-08-01

    The objective of the Canadian Advanced Nanospace eXperiment (CanX) program is to develop highly capable "nanospacecraft," or spacecraft under 10 kilograms, in short timeframes of 2-3 years. CanX missions offer low- cost and rapid access to space for scientists, technology developers, and operationally responsive missions. The Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) has developed the Canadian Advanced Nanospace eXperiment 2 (CanX-2) nanosatellite that launched in April 2008. CanX-2, a 3.5-kg, 10 x 10 x 34 cm satellite, features a collection of scientific and engineering payloads that push the envelope of capability for this class of spacecraft. The primary mission of CanX-2 is to test and demonstrate several enabling technologies for precise formation flight. These technologies include a custom cold-gas propulsion system, a 30 mNms nanosatellite reaction wheel as part of a three- axis stabilized momentum-bias attitude control system, and a commercially available GPS receiver. The secondary objective of CanX-2 is to fly a number of university experiments including an atmospheric spectrometer. At the time of writing CanX-2 has been in orbit for three weeks and has performed very well during preliminary commissioning. The mission, the engineering and scientific payloads, and the preliminary on-orbit commissioning experiences of CanX-2 are presented in this paper.

  12. Advances, experiences, and prospects of the International Soil Moisture Network

    NASA Astrophysics Data System (ADS)

    Dorigo, W.; van Oevelen, P. J.; Drusch, M.; Wagner, W.; Scipal, K.; Mecklenburg, S.

    2012-12-01

    In 2009, the International Soil Moisture Network (ISMN; http:www.ipf.tuwien.ac.at) was initiated as a platform to support calibration and validation of soil moisture products from remote sensing and land surface models, and to advance studies on the behavior of soil moisture over space and time. This international initiative is fruit of continuing coordinative efforts of the Global Energy and Water Cycle Experiment (GEWEX) in cooperation with the Group of Earth Observation (GEO) and the Committee on Earth Observation Satellites (CEOS). The decisive financial incentive was given by the European Space Agency (ESA) who considered the establishment of the network critical for optimizing the soil moisture products from the Soil Moisture and Ocean Salinity (SMOS) mission. The ISMN collects and harmonizes ground-based soil moisture data sets from a large variety of individually operating networks and makes them available through a centralized data portal. Meanwhile, almost 6000 soil moisture data sets from over 1300 sites, distributed among 34 networks worldwide, are contained in the database. The steadily increasing number of organizations voluntarily contributing to the ISMN, and the rapidly increasing number of studies based on the network show that the portal has been successful in reaching its primary goal to promote easy data accessibility to a wide variety of users. Recently, several updates of the system were performed to keep up with the increasing data amount and traffic, and to meet the requirements of many advanced users. Many datasets from operational networks (e.g., SCAN, the US Climate Reference Network, COSMOS, and ARM) are now assimilated and processed in the ISMN on a fully automated basis in near-real time. In addition, a new enhanced quality control system is currently being implemented. This presentation gives an overview of these recent developments, presents some examples of important scientific results based on the ISMN, and sketches an outlook for

  13. Experiences in Engaging the Public on Biotechnology Advances and Regulation.

    PubMed

    Quinlan, M Megan; Smith, Joe; Layton, Raymond; Keese, Paul; Agbagala, Ma Lorelie U; Palacpac, Merle B; Ball, Louise

    2016-01-01

    Public input is often sought as part of the biosafety decision-making process. Information and communication about the advances in biotechnology are part of the first step to engagement. This step often relies on the developers and introducers of the particular innovation, for example, an industry-funded website has hosted various authorities to respond to questions from the public. Alternative approaches to providing information have evolved, as demonstrated in sub-Saharan Africa where non-governmental organizations and associations play this role in some countries and subregions. Often times, those in the public who choose to participate in engagement opportunities have opinions about the overall biosafety decision process. Case-by-case decisions are made within defined regulatory frameworks, however, and in general, regulatory consultation does not provide the opportunity for input to the overall decision-making process. The various objectives on both sides of engagement can make the experience challenging; there are no clear metrics for success. The situation is challenging because public input occurs within the context of the local legislative framework, regulatory requirements, and the peculiarities of the fairly recent biosafety frameworks, as well as of public opinion and individual values. Public engagement may be conducted voluntarily, or may be driven by legislation. What can be taken into account by the decision makers, and therefore what will be gathered and the timing of consultation, also may be legally defined. Several practical experiences suggest practices for effective engagement within the confines of regulatory mandates: (1) utilizing a range of resources to facilitate public education and opportunities for understanding complex technologies; (2) defining in advance the goal of seeking input; (3) identifying and communicating with the critical public groups from which input is needed; (4) using a clearly defined approach to gathering and

  14. Experiences in Engaging the Public on Biotechnology Advances and Regulation

    PubMed Central

    Quinlan, M. Megan; Smith, Joe; Layton, Raymond; Keese, Paul; Agbagala, Ma. Lorelie U.; Palacpac, Merle B.; Ball, Louise

    2016-01-01

    Public input is often sought as part of the biosafety decision-making process. Information and communication about the advances in biotechnology are part of the first step to engagement. This step often relies on the developers and introducers of the particular innovation, for example, an industry-funded website has hosted various authorities to respond to questions from the public. Alternative approaches to providing information have evolved, as demonstrated in sub-Saharan Africa where non-governmental organizations and associations play this role in some countries and subregions. Often times, those in the public who choose to participate in engagement opportunities have opinions about the overall biosafety decision process. Case-by-case decisions are made within defined regulatory frameworks, however, and in general, regulatory consultation does not provide the opportunity for input to the overall decision-making process. The various objectives on both sides of engagement can make the experience challenging; there are no clear metrics for success. The situation is challenging because public input occurs within the context of the local legislative framework, regulatory requirements, and the peculiarities of the fairly recent biosafety frameworks, as well as of public opinion and individual values. Public engagement may be conducted voluntarily, or may be driven by legislation. What can be taken into account by the decision makers, and therefore what will be gathered and the timing of consultation, also may be legally defined. Several practical experiences suggest practices for effective engagement within the confines of regulatory mandates: (1) utilizing a range of resources to facilitate public education and opportunities for understanding complex technologies; (2) defining in advance the goal of seeking input; (3) identifying and communicating with the critical public groups from which input is needed; (4) using a clearly defined approach to gathering and

  15. Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping

    NASA Astrophysics Data System (ADS)

    Wen, Liang-Saw; Santschi, Peter H.; Tang, Degui

    1997-07-01

    It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority (>50%) of the colloidal trace metals had been transferred into the particulate phase (≥0.45 μm), except for 65Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe (˜60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of 59Fe and 110Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of 54Mn, 133Ba, 65Zn, 109Cd, 113Sn, and 60CO increased while the LMW (≤ 1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The values of the particle-water ( Kd) and colloid-water partitioning ( Kc) coefficients for most trace metals were similar to those observed in Galveston Bay waters, suggesting complementary results to field studies. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying

  16. The theory of delamination during drying of confined colloidal suspensions.

    PubMed

    Wallenstein, K J; Russel, W B

    2011-05-18

    Recent experiments on the drying of colloidal films in confined thin rectangular geometries show an interesting new phenomenon: the delamination of the colloidal suspension from the cavity wall. The theory developed in this paper explains the phenomenon by applying the Griffith energy criteria to a poroelastic film of Hertzian spheres. Prior to delamination, flow due to drying compresses the film in the direction of flow and generates tension in the transverse direction. Delamination allows relaxation in both the transverse tensile stresses and the axial compression. Preliminary numerical solutions suggest that the elastic energy recovered should increase linearly with the length of the close-packed film. That suggests a simple analytical solution that predicts the advancing of the delamination as the length of the close-packed region increases and explains qualitatively the essential features of the phenomenon. PMID:21525555

  17. Current advances in synchrotron radiation instrumentation for MX experiments.

    PubMed

    Owen, Robin L; Juanhuix, Jordi; Fuchs, Martin

    2016-07-15

    Following pioneering work 40 years ago, synchrotron beamlines dedicated to macromolecular crystallography (MX) have improved in almost every aspect as instrumentation has evolved. Beam sizes and crystal dimensions are now on the single micron scale while data can be collected from proteins with molecular weights over 10 MDa and from crystals with unit cell dimensions over 1000 Å. Furthermore it is possible to collect a complete data set in seconds, and obtain the resulting structure in minutes. The impact of MX synchrotron beamlines and their evolution is reflected in their scientific output, and MX is now the method of choice for a variety of aims from ligand binding to structure determination of membrane proteins, viruses and ribosomes, resulting in a much deeper understanding of the machinery of life. A main driving force of beamline evolution have been advances in almost every aspect of the instrumentation comprising a synchrotron beamline. In this review we aim to provide an overview of the current status of instrumentation at modern MX experiments. The most critical optical components are discussed, as are aspects of endstation design, sample delivery, visualisation and positioning, the sample environment, beam shaping, detectors and data acquisition and processing. PMID:27046341

  18. Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

  19. Interim Service ISDN Satellite (ISIS) hardware experiment development for advanced ISDN satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

  20. Colloidal Silver Products

    MedlinePlus

    ... can be dangerous to your health. What the Science Says About the Safety and Side Effects of ... homemade and commercial colloidal silver products. What the Science Says About the Effectiveness of Colloidal Silver Scientific ...

  1. Plutonium and Cesium Colloid Mediated Transport

    NASA Astrophysics Data System (ADS)

    Boukhalfa, H.; Dittrich, T.; Reimus, P. W.; Ware, D.; Erdmann, B.; Wasserman, N. L.; Abdel-Fattah, A. I.

    2013-12-01

    Plutonium and cesium have been released to the environment at many different locations worldwide and are present in spent fuel at significant levels. Accurate understanding of the mechanisms that control their fate and transport in the environment is important for the management of contaminated sites, for forensic applications, and for the development of robust repositories for the disposal of spent nuclear fuel and nuclear waste. Plutonium, which can be present in the environment in multiple oxidations states and various chemical forms including amorphous oxy(hydr)oxide phases, adsorbs/adheres very strongly to geological materials and is usually immobile in all its chemical forms. However, when associated with natural colloids, it has the potential to migrate significant distances from its point of release. Like plutonium, cesium is not very mobile and tends to remain adhered to geological materials near its release point, although its transport can be enhanced by natural colloids. However, the reactivity of plutonium and cesium are very different, so their colloid-mediated transport might be significantly different in subsurface environments. In this study, we performed controlled experiments in two identically-prepared columns; one dedicated to Pu and natural colloid transport experiments, and the other to Cs and colloid experiments. Multiple flow-through experiments were conducted in each column, with the effluent solutions being collected and re-injected into the same column two times to examine the persistence and scaling behavior of the natural colloids, Pu and Cs. The data show that that a significant fraction of colloids were retained in the first elution through each column, but the eluted colloids collected from the first run transported almost conservatively in subsequent runs. Plutonium transport tracked natural colloids in the first run but deviated from the transport of natural colloids in the second and third runs. Cesium transport tracked natural

  2. Remotely Controlled Mixers for Light Microscopy Module (LMM) Colloid Samples

    NASA Technical Reports Server (NTRS)

    Kurk, Michael A. (Andy)

    2015-01-01

    Developed by NASA Glenn Research Center, the LMM aboard the International Space Station (ISS) is enabling multiple biomedical science experiments. Techshot, Inc., has developed a series of colloid specialty cell systems (C-SPECS) for use in the colloid science experiment module on the LMM. These low-volume mixing devices will enable uniform particle density and remotely controlled repetition of LMM colloid experiments. By automating the experiment process, C-SPECS allow colloid samples to be processed more quickly. In addition, C-SPECS will minimize the time the crew will need to spend on colloid experiments as well as eliminate the need for multiple and costly colloid samples, which are expended after a single examination. This high-throughput capability will lead to more efficient and productive use of the LMM. As commercial launch vehicles begin routine visits to the ISS, C-SPECS could become a significant means to process larger quantities of high-value materials for commercial customers.

  3. Interactions between radioactively labeled colloids and natural particles: Evidence for colloidal pumping

    SciTech Connect

    Wen, L.S.; Santschi, P.H.; Tang, D.

    1997-07-01

    It has been hypothesized that colloidal forms of trace metals can be reactive intermediaries in the scavenging processes leading to the removal of their particulate forms. A series of radiotracer experiments using natural colloidal organic matter from Galveston Bay, USA were carried out in order to test this hypothesis. Suspended particle uptake of originally colloidally bound trace metals occurred in a matter of hours to days in estuarine waters. After ten days, the majority ( >50%) of the colloidal trace metals had been transferred into the particulate phase ({ge} 0.45{mu}m), except for {sup 65}Zn. Two distinctively different temporal regions of removal of colloidal trace metals were identified: a faster reaction during the first four hours, followed by a slower reaction after approximately one day. In a separate river water-seawater mixing experiment, the solid/solution partitioning of the radiotracers was investigated in the absence of suspended matter. About 30% of most of the elements, except Ag and Fe ({approximately}60%), were associated with a newly formed particulate phase after eight days. There were two major trends: (1) the particulate fraction of {sup 59}Fe and {sup 110}Ag increased while the colloidal fraction decreased, suggesting a colloidal pumping mechanism. (2) The particulate fraction of {sup 54}Mn, {sup 133}Ba, {sup 65}Zn, {sup 109}Cd, {sup 113}Sn, and {sup 60}Co increased while the LMW({le}1 kDa) fraction decreased, suggesting a direct uptake into the particulate fraction with less involvement of a transitory colloidal phase. The results from these experiments suggested two different pathways for colloidal tracer uptake by particles: (1) colloidal pumping of a major component (e.g., biopolymer) of the colloidal pool and (2) coagulation of trace components (e.g., phytochelatins) with varying affinities for different trace metals. 39 refs., 8 figs., 3 tabs.

  4. Electrohydrodynamically patterned colloidal crystals

    NASA Technical Reports Server (NTRS)

    Hayward, Ryan C. (Inventor); Poon, Hak F. (Inventor); Xiao, Yi (Inventor); Saville, Dudley A. (Inventor); Aksay, Ilhan A. (Inventor)

    2003-01-01

    A method for assembling patterned crystalline arrays of colloidal particles using ultraviolet illumination of an optically-sensitive semiconducting anode while using the anode to apply an electronic field to the colloidal particles. The ultraviolet illumination increases current density, and consequently, the flow of the colloidal particles. As a result, colloidal particles can be caused to migrate from non-illuminated areas of the anode to illuminated areas of the anode. Selective illumination of the anode can also be used to permanently affix colloidal crystals to illuminated areas of the anode while not affixing them to non-illuminated areas of the anode.

  5. Microbial effects on colloidal agglomeration

    SciTech Connect

    Hersman, L.

    1995-11-01

    Colloidal particles are known to enhance the transport of radioactive metals through soil and rock systems. This study was performed to determine if a soil microorganism, isolated from the surface samples collected at Yucca Mountain, NV, could affect the colloidal properties of day particles. The agglomeration of a Wyoming bentonite clay in a sterile uninoculated microbial growth medium was compared to the agglomeration in the medium inoculated with a Pseudomonas sp. In a second experiment, microorganisms were cultured in the succinate medium for 50 h and removed by centrifugation. The agglomeration of the clay in this spent was compared to sterile uninoculated medium. In both experiments, the agglomeration of the clay was greater than that of the sterile, uninoculated control. Based on these results, which indicate that this microorganism enhanced the agglomeration of the bentonite clay, it is possible to say that in the presence of microorganisms colloidal movement through a rock matrix could be reduced because of an overall increase in the size of colloidal particle agglomerates. 32 refs.

  6. Towards Structural Complexity with Colloids

    NASA Astrophysics Data System (ADS)

    Engel, Michael

    2012-02-01

    Colloids rather easily assemble into simple crystal structures like the face-centered cubic lattice or the body-centered cubic lattice. More complex phases are harder to achieve, but have recently been reported using a number of approaches. Yet, assembling complex structures often results from trial-and-error and is not well understood. In this presentation, we show how novel crystals, quasicrystals, and liquid crystals can be achieved with colloidal building blocks by varying the interactions and the shapes of the building blocks. Using computer simulations, we demonstrate the formation of unusually ordered phases both with isotropic pair potentials, as well as with facetted shapes like polyhedra. We describe new tools we have developed to perform complex structural analysis on simulated systems and show how they may be used to analyze real space images from colloid experiments. We also compare the assembled structures with densest packings of the building blocks and show that good packings can often be distinct from what is observed to assemble from the disordered state. This suggests that dense packings may not be illustrative of what is achievable in colloid experiments.

  7. A Novel Laboratory Course on Advanced ChE Experiments.

    ERIC Educational Resources Information Center

    Lauterbach, J.; White, S.; Liu, Z.; Bodner, G. M.; Delgass, W. N.

    1997-01-01

    Describes a novel approach to laboratory teaching that provides students with a learning environment which allows them to develop advanced experimental skills that are necessary for success in research and development environments. (DKM)

  8. Microfluidic colloid filtration

    PubMed Central

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-01-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

  9. Saturated Zone Colloid Transport

    SciTech Connect

    H. Viswanathan; P. Reimus

    2003-09-05

    Colloid retardation is influenced by the attachment and detachment of colloids from immobile surfaces. This analysis demonstrates the development of parameters necessary to estimate attachment and detachment of colloids and, hence, retardation in both fractured tuff and porous alluvium. Field and experimental data specific to fractured tuff are used for the analysis of colloid retardation in fractured tuff. Experimental data specific to colloid transport in alluvial material from Yucca Mountain as well as bacteriophage field studies in alluvial material, which are thought to be good analogs for colloid transport, are used to estimate attachment and detachment of colloids in the alluvial material. There are no alternative scientific approaches or technical methods for calculating these retardation factors.

  10. Microfluidic colloid filtration.

    PubMed

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J C; Wessling, Matthias

    2016-01-01

    Filtration of natural and colloidal matter is an essential process in today's water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a "cake layer" - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

  11. Microfluidic colloid filtration

    NASA Astrophysics Data System (ADS)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  12. EDITORIAL: Colloidal dispersions in external fields Colloidal dispersions in external fields

    NASA Astrophysics Data System (ADS)

    Löwen, Hartmut

    2012-11-01

    Colloidal dispersions have long been proven as pivotal model systems for equilibrium phase transition such as crystallization, melting and liquid-gas phase transition. The last decades have revealed that this is also true for nonequilibrium phenomena. In fact, the fascinating possibility to track the individual trajectories of colloidal particles has greatly advanced our understanding of collective behaviour in classical many-body systems and has helped to reveal the underlying physical principles of glass transition, crystal nucleation, and interfacial dynamics (to name just a few typical nonequilibrium effects). External fields can be used to bring colloids out of equilibrium in a controlled way. Different kinds of external fields can be applied to colloidal dispersions, namely shear flow, electric, magnetic and laser-optical fields, and confinement. Typical research areas can be sketched with the by now traditional complexity diagram (figure 1). The complexity of the colloidal system itself as embodied in statistical degrees of freedom is shown on the x-axis while the complexity of the problem posed, namely bulk, an inhomogeneity in equilibrium, steady state nonequilibrium and full time-dependent nonequilibrium are shown on the y-axis. The different external fields which can be imposed are indicated by the different hatched areas. figure1 Figure 1. Diagram of complexity for colloidal dispersions in external fields: while the x-axis shows the complexity of the system, the y-axis shows the complexity of the problem. Regions which can be accessed by different kinds of external fields are indicated. The arrows indicate recent research directions. Active particles are also indicated with a special complexity of internal degrees of freedom [1]. This collection of papers reflects the scientific programme of the International Conference on Colloidal Dispersions in External Fields III (CODEF III) which took place in Bonn-Bad Godesberg from 20-23 March 2012. This was the

  13. A Simple Photochemical Experiment for the Advanced Laboratory.

    ERIC Educational Resources Information Center

    Rosenfeld, Stuart M.

    1986-01-01

    Describes an experiment to provide students with: (1) an introduction to photochemical techniques and theory; (2) an experience with semimicro techniques; (3) an application of carbon-14 nuclear magnetic resonance; and (4) a laboratory with some qualities of a genuine experiment. These criteria are met in the photooxidation of 9,…

  14. Dynamics of Colloidal Disorder-Order Transition

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Experiments with colloidal solutions of plastic microspheres suspended in a liquid serve as models of how molecules interact and form crystals. For the Dynamics of Colloidal Disorder-Order Transition (CDOT) experiment, Paul Chaikin of Princeton University has identified effects that are attributable to Earth's gravity and demonstrated that experiments are needed in the microgravity of orbit. Space experiments have produced unexpected dendritic (snowflake-like) structures. To date, the largest hard sphere crystal grown is a 3 mm single crystal grown at the cool end of a ground sample. At least two more additional flight experiments are plarned aboard the International Space Station. This image is from a video downlink.

  15. Recent Experiences and Advances in Contrast-Enhanced Subharmonic Ultrasound

    PubMed Central

    Eisenbrey, John R.; Liu, Ji-Bin; Forsberg, Flemming

    2015-01-01

    Nonlinear contrast-enhanced ultrasound imaging schemes strive to suppress tissue signals in order to better visualize nonlinear signals from blood-pooling ultrasound contrast agents. Because tissue does not generate a subharmonic response (i.e., signal at half the transmit frequency), subharmonic imaging has been proposed as a method for isolating ultrasound microbubble signals while suppressing surrounding tissue signals. In this paper, we summarize recent advances in the use of subharmonic imaging in vivo. These advances include the implementation of subharmonic imaging on linear and curvilinear arrays, intravascular probes, and three-dimensional probes for breast, renal, liver, plaque, and tumor imaging. PMID:26090430

  16. Pore water colloid properties in argillaceous sedimentary rocks.

    PubMed

    Degueldre, Claude; Cloet, Veerle

    2016-11-01

    The focus of this work is to evaluate the colloid nature, concentration and size distribution in the pore water of Opalinus Clay and other sedimentary host rocks identified for a potential radioactive waste repository in Switzerland. Because colloids could not be measured in representative undisturbed porewater of these host rocks, predictive modelling based on data from field and laboratory studies is applied. This approach allowed estimating the nature, concentration and size distributions of the colloids in the pore water of these host rocks. As a result of field campaigns, groundwater colloid concentrations are investigated on the basis of their size distribution quantified experimentally using single particle counting techniques. The colloid properties are estimated considering data gained from analogue hydrogeochemical systems ranging from mylonite features in crystalline fissures to sedimentary formations. The colloid concentrations were analysed as a function of the alkaline and alkaline earth element concentrations. Laboratory batch results on clay colloid generation from compacted pellets in quasi-stagnant water are also reported. Experiments with colloids in batch containers indicate that the size distribution of a colloidal suspension evolves toward a common particle size distribution independently of initial conditions. The final suspension size distribution was found to be a function of the attachment factor of the colloids. Finally, calculations were performed using a novel colloid distribution model based on colloid generation, aggregation and sedimentation rates to predict under in-situ conditions what makes colloid concentrations and size distributions batch- or fracture-size dependent. The data presented so far are compared with the field and laboratory data. The colloid occurrence, stability and mobility have been evaluated for the water of the considered potential host rocks. In the pore water of the considered sedimentary host rocks, the clay

  17. Colloidal Suspensions of Rodlike Nanocrystals and Magnetic Spheres under an External Magnetic Stimulus: Experiment and Molecular Dynamics Simulation.

    PubMed

    May, Kathrin; Eremin, Alexey; Stannarius, Ralf; Peroukidis, Stavros D; Klapp, Sabine H L; Klein, Susanne

    2016-05-24

    Using experiments and molecular dynamics simulations, we explore magnetic field-induced phase transformations in suspensions of nonmagnetic rodlike and magnetic sphere-shaped particles. We experimentally demonstrate that an external uniform magnetic field causes the formation of small, stable clusters of magnetic particles that, in turn, induce and control the orientational order of the nonmagnetic subphase. Optical birefringence was studied as a function of the magnetic field and the volume fractions of each particle type. Steric transfer of the orientational order was investigated by molecular dynamics (MD) simulations; the results are in qualitative agreement with the experimental observations. By reproducing the general experimental trends, the MD simulation offers a cohesive bottom-up interpretation of the physical behavior of such systems, and it can also be regarded as a guide for further experimental research. PMID:27119202

  18. Quantification of hydrophobic interaction affinity of colloids

    NASA Astrophysics Data System (ADS)

    Saini, G.; Nasholm, N.; Wood, B. D.

    2009-12-01

    Colloids play an important role in a wide variety of disciplines, including water and wastewater treatment, subsurface transport of metals and organic contaminants, migration of fines in oil reservoirs, biocolloid (virus and bacteria) transport in subsurface, and are integral to laboratory transport studies. Although the role of hydrophobicity in adhesion and transport of colloids, particularly bacteria, is well known; there is scarcity of literature regarding hydrophobicity measurement of non-bacterial colloids and other micron-sized particles. Here we detail an experimental approach based on differential partitioning of colloids between two liquid phases (hydrocarbon and buffer) as a measure of the hydrophobic interaction affinity of colloids. This assay, known as Microbial adhesion to hydrocarbons or MATH, is frequently used in microbiology and bacteriology for quantifying the hydrophobicity of microbes. Monodispersed colloids and particles, with sizes ranging from 1 micron to 33 micron, were used for the experiments. A range of hydrophobicity values were observed for different particles. The hydrophobicity results are also verified against water contact angle measurements of these particles. This liquid-liquid partitioning assay is quick, easy-to-perform and requires minimal instrumentation. Estimation of the hydrophobic interaction affinity of colloids would lead to a better understanding of their adhesion to different surfaces and subsequent transport in porous media.

  19. Colloid suspension stability and transport through unsaturated porous media

    SciTech Connect

    McGraw, M.A.; Kaplan, D.I.

    1997-04-01

    Contaminant transport is traditionally modeled in a two-phase system: a mobile aqueous phase and an immobile solid phase. Over the last 15 years, there has been an increasing awareness of a third, mobile solid phase. This mobile solid phase, or mobile colloids, are organic or inorganic submicron-sized particles that move with groundwater flow. When colloids are present, the net effect on radionuclide transport is that radionuclides can move faster through the system. It is not known whether mobile colloids exist in the subsurface environment of the Hanford Site. Furthermore, it is not known if mobile colloids would likely exist in a plume emanating from a Low Level Waste (LLW) disposal site. No attempt was made in this study to ascertain whether colloids would form. Instead, experiments and calculations were conducted to evaluate the likelihood that colloids, if formed, would remain in suspension and move through saturated and unsaturated sediments. The objectives of this study were to evaluate three aspects of colloid-facilitated transport of radionuclides as they specifically relate to the LLW Performance Assessment. These objectives were: (1) determine if the chemical conditions likely to exist in the near and far field of the proposed disposal site are prone to induce flocculation (settling of colloids from suspension) or dispersion of naturally occurring Hanford colloids, (2) identify the important mechanisms likely involved in the removal of colloids from a Hanford sediment, and (3) determine if colloids can move through unsaturated porous media.

  20. Analysis of colloids released from bentonite and crushed rock

    NASA Astrophysics Data System (ADS)

    Lahtinen, M.; Hölttä, P.; Riekkola, M.-L.; Yohannes, G.

    Inorganic colloids are present in natural groundwater but colloids can also be produced from degraded Engineered Barrier System (EBS) materials. The potential relevance of colloids for radionuclide transport is highly dependent on the release and stability of colloids in different chemical environments and their interaction with radionuclides. In this work, release and stability of inorganic colloids were determined from bentonite and crushed rock which will be used in the tunnel back-fill. In the batch dispersion experiments, MX-80 bentonite powder or crushed rock samples of mica gneiss, unaltered and two altered tonalites were added to Milli-Q water, saline OLSO, and low salinity Allard reference water with adjusted pH values 7-9. After 4 months, pH, particle size distribution, zeta potential, morphology, elemental composition, and colloid concentration were analyzed. The release and stability of colloids depended significantly on groundwater salinity, pH, and the degree of alteration of the rock. In saline OLSO, zeta potential values near zero, wide particle size range, and low colloid concentrations indicated particle aggregation and instable colloidal dispersion. In low salinity Allard and Milli-Q water, high or moderate negative zeta potential values, smaller particle sizes, and higher colloid concentrations than in OLSO indicated the existence of stable colloids.

  1. Infrared colloidal lead chalcogenide nanocrystals: synthesis, properties, and photovoltaic applications.

    PubMed

    Fu, Huiying; Tsang, Sai-Wing

    2012-04-01

    Simple solution phase, catalyst-free synthetic approaches that offer monodispersed, well passivated, and non-aggregated colloidal semiconductor nanocrystals have presented many research opportunities not only for fundamental science but also for technological applications. The ability to tune the electrical and optical properties of semiconductor nanocrystals by manipulating the size and shape of the crystals during the colloidal synthesis provides potential benefits to a variety of applications including photovoltaic devices, light-emitting diodes, field effect transistors, biological imaging/labeling, and more. Recent advances in the synthesis and characterization of colloidal lead chalcogenide nanocrystals and the achievements in colloidal PbS or PbSe nanocrystals solar cells have demonstrated the promising application of infrared-emitting colloidal lead chalcogenide nanocrystals in photovoltaic devices. Here, we review recent progress in the synthesis and optical properties of colloidal lead chalcogenide nanocrystals. We focus in particular upon the size- and shape-controlled synthesis of PbS, PbSe, and PbTe nanocrystals by using different precursors and various stabilizing surfactants for the growth of the colloidal nanocrystals. We also summarize recent advancements in the field of colloidal nanocrystals solar cells based on colloidal PbS and PbSe nanocrystals. PMID:22382898

  2. In Situ Techniques for Monitoring Electrochromism: An Advanced Laboratory Experiment

    ERIC Educational Resources Information Center

    Saricayir, Hakan; Uce, Musa; Koca, Atif

    2010-01-01

    This experiment employs current technology to enhance and extend existing lab content. The basic principles of spectroscopic and electroanalytical techniques and their use in determining material properties are covered in some detail in many undergraduate chemistry programs. However, there are limited examples of laboratory experiments with in…

  3. Advanced missions safety. Volume 3: Appendices. Part 2: Experiment

    NASA Technical Reports Server (NTRS)

    Hinton, M. G., Jr.

    1972-01-01

    Supporting documentation pertaining to the hazards of transporting experimental equipment on the Earth Orbit Shuttle is presented. The subjects discussed are: (1) experiment and hardware definition, (2) hazard analysis, (3) preventive measure assessment, (4) preventive measures statements, (5) remedial measure assessment, and (6) experiment interaction safety considerations.

  4. UZ Colloid Transport Model

    SciTech Connect

    M. McGraw

    2000-04-13

    The UZ Colloid Transport model development plan states that the objective of this Analysis/Model Report (AMR) is to document the development of a model for simulating unsaturated colloid transport. This objective includes the following: (1) use of a process level model to evaluate the potential mechanisms for colloid transport at Yucca Mountain; (2) Provide ranges of parameters for significant colloid transport processes to Performance Assessment (PA) for the unsaturated zone (UZ); (3) Provide a basis for development of an abstracted model for use in PA calculations.

  5. Colloids in food: ingredients, structure, and stability.

    PubMed

    Dickinson, Eric

    2015-01-01

    This article reviews progress in the field of food colloids with particular emphasis on advances in novel functional ingredients and nanoscale structuring. Specific aspects of ingredient development described here are the stabilization of bubbles and foams by the protein hydrophobin, the emulsifying characteristics of Maillard-type protein-polysaccharide conjugates, the structural and functional properties of protein fibrils, and the Pickering stabilization of dispersed droplets by food-grade nanoparticles and microparticles. Building on advances in the nanoscience of biological materials, the application of structural design principles to the fabrication of edible colloids is leading to progress in the fabrication of functional dispersed systems-multilayer interfaces, multiple emulsions, and gel-like emulsions. The associated physicochemical insight is contributing to our mechanistic understanding of oral processing and textural perception of food systems and to the development of colloid-based strategies to control delivery of nutrients during food digestion within the human gastrointestinal tract. PMID:25422877

  6. Fabrication and Characterization of Colloidal Crystal Thin Films

    ERIC Educational Resources Information Center

    Rodriguez, I.; Ramiro-Manzano, F.; Meseguer, F.; Bonet, E.

    2011-01-01

    We present a laboratory experiment that allows undergraduate or graduate students to get introduced to colloidal crystal research concepts in an interesting way. Moreover, such experiments and studies can also be useful in the field of crystallography or solid-state physics. The work concerns the growth of colloidal crystal thin films obtained…

  7. Colloidal Gelation-2 and Colloidal Disorder-Order Transition-2 Investigations Conducted on STS-95

    NASA Technical Reports Server (NTRS)

    Hoffmann, Monica T.

    2000-01-01

    The Colloidal Gelation-2 (CGEL 2) and Colloidal Disorder-Order Transition-2 (CDOT 2) investigations flew on Space Shuttle Discovery mission STS-95 (also known as the John Glenn Mission). These investigations were part of a series of colloid experiments designed to help scientists answer fundamental science questions and reduce the trial and error involved in developing new and better materials. Industries dealing with semiconductors, electro-optics, ceramics, and composites are just a few that may benefit from this knowledge. The goal of the CGEL 2 investigation was to study the fundamental properties of colloids to help scientists better understand their nature and make them more useful for technology. Colloids consist of very small (submicron) particles suspended in a fluid. They play a critical role in the technology of this country, finding uses in materials ranging from paints and coatings to drugs, cosmetics, food, and drink. Although these products are routinely produced and used, there are still many aspects of their behavior about which scientists know little. Understanding their structures may allow scientists to manipulate the physical properties of colloids (a process called "colloidal engineering") to produce new materials and products. Colloid research may even improve the processing of known products to enhance their desirable properties.

  8. Fabrication and characterization of colloidal crystal thin films

    NASA Astrophysics Data System (ADS)

    Rodríguez, I.; Ramiro-Manzano, F.; Meseguer, F.; Bonet, E.

    2011-03-01

    We present a laboratory experiment that allows undergraduate or graduate students to get introduced to colloidal crystal research concepts in an interesting way. Moreover, such experiments and studies can also be useful in the field of crystallography or solid-state physics. The work concerns the growth of colloidal crystal thin films obtained from the crystallization of a latex colloidal solution in a wedge cell. Depending on the thickness of the sample, microcrystals with different structures and orientation are obtained. Colloidal arrangements are studied by scanning electronic microscopy images of the top and edge views of several areas of the crystals.

  9. Principles of Precision Spectrophotometry: An Advanced Undergraduate Experiment

    ERIC Educational Resources Information Center

    Billmeyer, Fred W., Jr.

    1974-01-01

    Describes an experiment designed to familiarize students with the operation of a precision spectrophotometer, the effects of changes in operating variables, and the characteristics of such components as sources and detectors. (SLH)

  10. Advanced photon source experience with vacuum chambers for insertion devices

    SciTech Connect

    Hartog, P.D.; Grimmer, J.; Xu, S.; Trakhtenberg, E.; Wiemerslage, G.

    1997-08-01

    During the last five years, a new approach to the design and fabrication of extruded aluminum vacuum chambers for insertion devices was developed at the Advanced Photon Source (APS). With this approach, three different versions of the vacuum chamber, with vertical apertures of 12 mm, 8 mm, and 5 mm, were manufactured and tested. Twenty chambers were installed into the APS vacuum system. All have operated with beam, and 16 have been coupled with insertion devices. Two different vacuum chambers with vertical apertures of 16 mm and 11 mm were developed for the BESSY-II storage ring and 3 of 16 mm chambers were manufactured.

  11. Effective Forces Between Colloidal Particles

    NASA Technical Reports Server (NTRS)

    Tehver, Riina; Banavar, Jayanth R.; Koplik, Joel

    1999-01-01

    Colloidal suspensions have proven to be excellent model systems for the study of condensed matter and its phase behavior. Many of the properties of colloidal suspensions can be investigated with a systematic variation of the characteristics of the systems and, in addition, the energy, length and time scales associated with them allow for experimental probing of otherwise inaccessible regimes. The latter property also makes colloidal systems vulnerable to external influences such as gravity. Experiments performed in micro-ravity by Chaikin and Russell have been invaluable in extracting the true behavior of the systems without an external field. Weitz and Pusey intend to use mixtures of colloidal particles with additives such as polymers to induce aggregation and form weak, tenuous, highly disordered fractal structures that would be stable in the absence of gravitational forces. When dispersed in a polarizable medium, colloidal particles can ionize, emitting counterions into the solution. The standard interaction potential in these charged colloidal suspensions was first obtained by Derjaguin, Landau, Verwey and Overbeek. The DLVO potential is obtained in the mean-field linearized Poisson-Boltzmann approximation and thus has limited applicability. For more precise calculations, we have used ab initio density functional theory. In our model, colloidal particles are charged hard spheres, the counterions are described by a continuum density field and the solvent is treated as a homogeneous medium with a specified dielectric constant. We calculate the effective forces between charged colloidal particles by integrating over the solvent and counterion degrees of freedom, taking into account the direct interactions between the particles as well as particle-counterion, counterion-counterion Coulomb, counterion entropic and correlation contributions. We obtain the effective interaction potential between charged colloidal particles in different configurations. We evaluate two

  12. Laser Light Scattering, from an Advanced Technology Development Program to Experiments in a Reduced Gravity Environment

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Tscharnuter, Walther W.; Macgregor, Andrew D.; Dautet, Henri; Deschamps, Pierre; Boucher, Francois; Zuh, Jixiang; Tin, Padetha; Rogers, Richard B.; Ansari, Rafat R.

    1994-01-01

    Recent advancements in laser light scattering hardware are described. These include intelligent single card correlators; active quench/active reset avalanche photodiodes; laser diodes; and fiber optics which were used by or developed for a NASA advanced technology development program. A space shuttle experiment which will employ aspects of these hardware developments is previewed.

  13. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  14. Containerless preparation of advanced optical glasses: Experiment 77F095

    NASA Technical Reports Server (NTRS)

    Happe, R. A.; Kim, K. S.

    1982-01-01

    Containerless processing of optical glasses was studied in preparation for space shuttle MEA flight experiments. Ground based investigation, experiment/hardware coordination activities and development of flight experiment and sample characterization plans were investigated. In the ground based investigation over 100 candidate glass materials for space processing were screened and promising compositions were identified. The system of Nb2O5-TiO2-CaO was found to be very rich with containerless glass compositions and as extensive number of the oxides combinations were tried resulting in a glass formation ternary phase diagram. The frequent occurrence of glass formation by containerless processing among the compositions for which no glass formations were previously reported indicated the possibility and an advantage of containerless processing in a terrestrial environment.

  15. Determination of the Performance Parameters of a Spectrophotometer: An Advanced Experiment.

    ERIC Educational Resources Information Center

    Cope, Virgil W.

    1978-01-01

    Describes an advanced analytical chemistry laboratory experiment developed for the determination of the performance parameters of a spectrophotometer. Among the parameters are the baseline linearity with wavelength, wavelength accuracy and respectability, stray light, noise level and pen response time. (HM)

  16. The Synthesis and Proton NMR Spectrum of Methyl 7-Cycloheptatrienylacetate: An Advanced Undergraduate Laboratory Experiment.

    ERIC Educational Resources Information Center

    Jurch, G. R., Jr.; And Others

    1980-01-01

    Describes an advanced undergraduate laboratory experiment designed to give the senior chemistry student an opportunity to apply several synthetic and purification techniques as well as possibilities for the application of NMR spectroscopy. (CS)

  17. Stereospecificity of NAD+/NADH Reactions: A Project Experiment for Advanced Undergraduates.

    ERIC Educational Resources Information Center

    Lowrey, Jonathan S.; And Others

    1981-01-01

    Presents background information, materials needed, and experimental procedures to study enzymes dependent on pyridine nucleotide coenzymes (NAD/NADH). The experiments, suitable for advanced organic or biochemistry courses, require approximately 10-15 hours to complete. (SK)

  18. Interface colloidal robotic manipulator

    DOEpatents

    Aronson, Igor; Snezhko, Oleksiy

    2015-08-04

    A magnetic colloidal system confined at the interface between two immiscible liquids and energized by an alternating magnetic field dynamically self-assembles into localized asters and arrays of asters. The colloidal system exhibits locomotion and shape change. By controlling a small external magnetic field applied parallel to the interface, structures can capture, transport, and position target particles.

  19. The Columbus, Ohio, Experiment with Advanced Telebook Systems.

    ERIC Educational Resources Information Center

    Stetten, Kenneth J.; McElhaney, William E.

    This is the Final report of a 3-year, 3-phase experiment on the Telebook service, which is a system for delivering the recorded voice of Talking Books directly and electronically to the homes of blind and handicapped persons upon their request at any time of the day or night. The purpose of the third phase was to determine the long-term…

  20. Chemical release and radiation effects experiment advanced planning and coordination

    NASA Technical Reports Server (NTRS)

    Vaughan, William W.; Alzmann, Melanie

    1991-01-01

    The efforts conducted to provide assessments and planning support for the Chemical Release and Radiation Effects Satellite (CRRES) Experiments are summarized. Included are activities regarding scientific working group and workshop development including the preparation of descriptive information on the CRRES Project.

  1. Light Scattering by Polymers: Two Experiments for Advanced Undergraduates.

    ERIC Educational Resources Information Center

    Matthews, G. P.

    1984-01-01

    Background information, procedures, equipment, and results for two experiments are presented. The first involves the measurement of the mass-average and degree of coiling of polystyrene and is interpreted by the full mathematical theory of light scattering. The second is the study of transitions in gelatin. (JN)

  2. Plan of advanced satellite communication experiments using ETS-6

    NASA Technical Reports Server (NTRS)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  3. Advancing Intercultural Competency: Canadian Engineering Employers' Experiences with Immigrant Engineers

    ERIC Educational Resources Information Center

    Friesen, Marcia; Ingram, Sandra

    2013-01-01

    This paper explores Canadian engineering employers' perceptions of and experiences with internationally educated engineers (recent immigrants to Canada) employed in their organisations for varying lengths of time. Qualitative data were collected from employers using focus group methodology. Findings reflected employers' observations of culturally…

  4. Chemical release and radiation effects experiment advanced planned

    NASA Technical Reports Server (NTRS)

    Vaughan, William W.; Alzmann, Melanie

    1990-01-01

    A summary of the efforts conducted to provide assessments and planning support for the Chemical Release and Radiation Experiment Satellite (CRRES) is reported. Included are activities regarding scientific working group and workshop development including the preparation of descriptive information on the CRRES project.

  5. Technology Advancements Enhance Aircraft Support of Experiment Campaigns

    NASA Technical Reports Server (NTRS)

    Vachon, Jacques J.

    2009-01-01

    For over 30 years, the NASA Airborne Science Program has provided airborne platforms for space bound instrument development, for calibrating new and existing satellite systems, and for making in situ and remote sensing measurements that can only be made from aircraft. New technologies have expanded the capabilities of aircraft that are operated for these missions. Over the last several years a new technology investment portfolio has yielded improvements that produce better measurements for the airborne science communities. These new technologies include unmanned vehicles, precision trajectory control and advanced telecommunications capabilities. We will discuss some of the benefits of these new technologies and systems which aim to provide users with more precision, lower operational costs, quicker access to data, and better management of multi aircraft and multi sensor campaigns.

  6. Advanced Thin Ionization Calorimeter (ATIC) balloon experiment: expected performance

    NASA Astrophysics Data System (ADS)

    Seo, Eun-Suk; Adams, James H.; Bashindzhagyan, G. L.; Dudnik, Alexey V.; Fazely, Ali R.; Garcia, L.; Grigorov, Naum L.; Guzik, T. Gregory; Inderhees, Susan E.; Isbert, Joachim; Jung, H. C.; Khein, L.; Kim, Sun-Kee; Kroeger, Richard A.; McDonald, Frank B.; Panasyuk, Mikhail I.; Park, Choong-Soo; Schmidt, Wolfgang K.; Dion-Schwartz, C.; Senchishin, V. G.; Wang, J. Z.; Wefel, John P.; Zatsepin, Viktor I.; Zinn, S. Y.

    1996-10-01

    An advanced thin ionization calorimeter (ATIC) will be used to investigate the charge composition and energy spectra of ultrahigh energy primary cosmic rays in a series of long- duration balloon flights. While obtaining new high priority scientific results, this balloon payload can also serve as a proof of concept for a BGO calorimeter-based instrument on the International Space Station. The ATIC technical details are presented in a companion paper at this conference. Here we discuss the expected performance of the instrument based on a GEANT code developed for simulating nuclear- electromagnetic cascades initiated by protons. For simulations of helium and heavy nuclei, a nucleus-nucleus interaction event generator LUCIAE was linked to the GEANT based program. Using these models, the design of the ATIC detector system has been optimized by simulating the instrument response to particles of different charges over the energy range to be covered. Results of these simulations are presented and discussed.

  7. Development of performance criteria for advanced Viking seismic experiments

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The characteristics and requirements of the seismic instrument for mapping the internal structure of the planet Mars are briefly described. The types of signals expected to exist are microseismic background generated by wind and pressure variations and thermal effects, disturbances of or in the landed vehicle, signals caused by faulting and volcanic activity, and signals due to meteoritic impacts. The advanced instrument package should include a short-period vertical component system, a long-period or wide-band 3-component system, a high frequency vertical component system, and a system for detection and rejection of lander noises. The Viking '75, Surveyor, and Apollo systems are briefly described as potential instruments to be considered for modification. Data processing and control systems are also summarized.

  8. Lead-bismuth eutectic as advanced reactor collant : operational experience

    SciTech Connect

    Woloshun, K. A.; Watts, V.; Li, N.

    2004-01-01

    Some proposed advanced reactor concepts would be cooled by lead or lead-bismuth eutectic (LBE). An LBE test loop was designed and built at Los Alamos to develop the engineering and materials technology necessary to successfully implement LBE as a coolant (Fig. 1). Operational since December 2001, this test loop has been used to develop and demonstrate safe operation, oxygen concentration and metal corrosion control, instrumentation, thermal-hydraulic performance of heat exchangers and recuperators, and free convection and forced pumping. This paper discusses the technology development and lessons learned from the operation of this facility. A LBE test loop has been operational since December 2001. Using procedures, training, and engineering controls, this loop has operated without an accident. Continuous improvements in operation procedures and instrumentation over these years have resulted in a facility of high reliability, providing the groundwork for the use of LBE as a reactor coolant for temperatures up to 550 C.

  9. Advances in neurosurgery: The Fujita Health University experience

    PubMed Central

    Kumar, Ashish

    2011-01-01

    In a world with rapidly changing technologies in the field of neurosurgery, Japan leads the world in many subspecialities like vascular neurosurgery. Apart from this, neuro-oncology and spinal surgeries are also among the premium quality operations performed in the region. I would like to share my experience of spending 3 months at the Fujita Health University, Nagoya, Japan, and the rich expertise and technologies encountered during the period, which made me understand Neurosurgery in a better way. PMID:22059102

  10. Advanced Cosmic Ray Composition Experiment for Space Station (ACCESS)

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L.; Wefel, John P.

    1999-01-01

    In 1994 the first high-energy particle physics experiment for the Space Station, the Alpha Magnetic Spectrometer (AMS), was selected by NASA's Administrator as a joint collaboration with the U.S. Department of Energy (DOE). The AMS program was chartered to place a magnetic spectrometer in Earth orbit and search for cosmic antimatter. A natural consequence of this decision was that NASA would begin to explore cost-effective ways through which the design and implementation of AMS might benefit other promising payload experiments which were evolving from the Office of Space Science. The first such experiment to come forward was ACCESS in 1996. It was proposed as a new mission concept in space physics to place a cosmic-ray experiment of weight, volume, and geometry similar to the AMS on the ISS, and replace the latter as its successor when the AMS is returned to Earth. This was to be an extension of NASA's sub-orbital balloon program, with balloon payloads serving as the precursor flights and heritage for ACCESS. The balloon programs have always been a cost-effective NASA resource since the particle physics instrumentation for balloon and space applications are directly related. The next step was to expand the process, pooling together expertise from various NASA centers and universities while opening up definition of the ACCESS science goals to the international community through the standard practice of peer-review. This process is still on-going and the Accommodation Study presented here will discuss the baseline definition of ACCESS as we understand it today. Further detail on the history, scope, and background of the study is provided in Appendix A.

  11. Irradiation of the First Advanced Gas Reactor Fuel Development and Qualification Experiment in the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover; David A. Petti

    2008-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation. The design of the first experiment (designated AGR-1) was completed in 2005, and the fabrication and assembly of the test train as well as the support systems and fission product monitoring system that monitor and control the experiment during irradiation were completed in September 2006. The experiment was inserted in the ATR in December 2006, and is serving as a shakedown test of the multi-capsule experiment design that will be used in the subsequent irradiations as well as a test of the early variants of the fuel produced under this program. The experiment test train as well as the monitoring, control, and data collection systems are discussed and the status of the experiment is provided.

  12. Bunch cleaning strategies and experiments at the Advanced Photon Source.

    SciTech Connect

    Sereno, N. S.

    1999-04-15

    The Advanced Photon Source (APS) design incorporated a positron accumulator ring (PAR) as part of the injector chain. In order to increase reliability and accommodate other uses of the injector, APS will run with electrons, eliminating the need for the PAR, provided another method of eliminating rf bucket pollution in the APS is found. Satellite bunches captured from an up to 30-ns-long beam from the linac need to be removed in the injector synchrotron and storage ring. The bunch cleaning method considered here relies on driving a stripline kicker with an amplitude modulated (AM) carrier signal where the carrier is at a revolution harmonic sideband corresponding to the vertical tune. The envelope waveform is phased so that all bunches except a single target bunch (eventually to be injected into the storage ring) are resonated vertically into a scraper. The kicker is designed with a large enough shunt impedance to remove satellite bunches from the injection energy of 0.4 GeV up to 1 GeV. Satellite bunch removal in the storage ring relies on the single bunch current tune shift resulting from the machine impedance. Small bunches remaining after initial preparation in the synchrotron may be removed by driving the beam vertically into a scraper using a stripline kicker operating at a sideband corresponding to the vertical tune for small current bunches. In this paper both design specifications and bunch purity measurements are reported for both the injector synchrotron and storage ring.

  13. Aerospace Engineering Systems and the Advanced Design Technologies Testbed Experience

    NASA Technical Reports Server (NTRS)

    VanDalsem, William R.; Livingston, Mary E.; Melton, John E.; Torres, Francisco J.; Stremel, Paul M.

    1999-01-01

    Continuous improvement of aerospace product development processes is a driving requirement across much of the aerospace community. As up to 90% of the cost of an aerospace product is committed during the first 10% of the development cycle, there is a strong emphasis on capturing, creating, and communicating better information (both requirements and performance) early in the product development process. The community has responded by pursuing the development of computer-based systems designed to enhance the decision-making capabilities of product development individuals and teams. Recently, the historical foci on sharing the geometrical representation and on configuration management are being augmented: 1) Physics-based analysis tools for filling the design space database; 2) Distributed computational resources to reduce response time and cost; 3) Web-based technologies to relieve machine-dependence; and 4) Artificial intelligence technologies to accelerate processes and reduce process variability. The Advanced Design Technologies Testbed (ADTT) activity at NASA Ames Research Center was initiated to study the strengths and weaknesses of the technologies supporting each of these trends, as well as the overall impact of the combination of these trends on a product development event. Lessons learned and recommendations for future activities are reported.

  14. Experience with fast neutron therapy for locally advanced sarcomas

    SciTech Connect

    Salinas, R.; Hussey, D.H.; Fletcher, G.H.; Lindberg, R.D.; Martin, R.G.; Peters, L.J.; Sinkovics, J.G.

    1980-03-01

    Between October 1972 and April 1978, 34 patients with locally advanced sarcomas were treated with fast neutrons using the Texas A and M variable energy cyclotron. The clinical material included 29 patients with soft tissue sarcomas, 4 with chondrosarcomas, and one with an osteosarcoma. The best results were achieved for patients with soft tissue sarcomas; 69% (20/29) had local control of their tumor. Only one of 4 patients with chondrosarcomas was classified as having local tumor control, and one patient with osteosarcoma had persistent disease. With most fractionation schedules, local tumor control was superior for patients who received doses greater than 6500 rad/sub eq/ (2100 rad/sub n..gamma../ with 50 MeV/sub d ..-->.. Be/ neutrons). The incidence of major complications was notably increased when maximum radiation doses of 7500 rad/sub eq/ or greater were administered (2400 rad/sub n..gamma../ with 50 MeV/sub d ..-->.. Be/ neutrons). In patients who underwent subsequent surgery, healing was satisfactory if the maximum radiation dose was limited to 4500 to 5500 rad/sub eq/(1450 to 1775 rad/sub n..gamma../ with 50 MeV/sub d ..-->.. Be/ neutrons).

  15. Advanced Thin Ionization Calorimeter (ATIC) balloon experiment: instrumentation

    NASA Astrophysics Data System (ADS)

    Guzik, T. Gregory; Adams, James H.; Bashindzhagyan, G. L.; Dudnik, Alexey V.; Ellison, Steven B.; Fazely, Ali R.; Garcia, L.; Grigorov, Naum L.; Inderhees, Susan E.; Isbert, Joachim; Jung, H. C.; Khein, L.; Kim, Sun-Kee; Kroeger, Richard A.; Lockwood, R.; McDonald, Frank B.; Panasyuk, Mikhail I.; Park, Choong-Soo; Price, B.; Schmidt, Wolfgang K.; Dion-Schwartz, C.; Senchishin, V. G.; Seo, Eun-Suk; Wefel, John P.; Wang, J. Z.; Zatsepin, Viktor I.; Zinn, S. Y.

    1996-10-01

    A new balloon instrument, the advanced thin ionization calorimeter (ATIC), is currently under development by an international collaboration involving researchers in the U.S., Germany, Korea, Russia and the Ukraine. The instrument will be used, in a series of long duration balloon flights, to investigate the charge composition and energy spectra of primary cosmic rays over the energy range from about 1010 to 1014 eV. The ATIC instrument is designed around a new technology, fully active Bismuth Germanate (BGO) ionization calorimeter that is used to measure the energy deposited by the cascades formed by particles interacting in an approximately 1 proton interaction length thick carbon target. The charge module comprises a highly segmented, triply redundant set of detectors (scintillator, silicon matrix and Cherenkov) that together give good incident charge resolution plus rejection of the 'backscattered' particles from the interaction. Trajectory information is obtained both from scintillator layers and from the cascade profile throughout the BGO calorimeter. This instrument is specifically designed to take advantage of the existing NASA long duration balloon flight capability in Antarctica and/or the Northern Hemisphere. The ATIC instrumentation is presented here, while a companion paper at this conference discusses the expected performance.

  16. Recent Advances In Science Support For Isolated Droplet Combustion Experiments

    NASA Technical Reports Server (NTRS)

    Dryer, F. L.; Kazakov, A.; Urban, B. D.; Kroenlein, K.

    2003-01-01

    In a joint program involving Prof. F.A. Williams of the University of California, San Diego and Dr. V. Nayagam of the National Center for Microgravity Research, the combustion characteristics of isolated liquid fuel droplets of n-heptane, n-decane, methanol, methanol-water, ethanol and ethanol-water having initial diameters between about 1 mm and 6 mm continues to be investigated. The objectives of the work are to improve fundamental knowledge of droplet combustion dynamics for pure fuels and fuel-water mixtures through microgravity experiments and theoretical analyses. The Princeton contributions support the engineering design, data analysis, and data interpretation requirements for the study of initially single component, spherically symmetric, isolated droplet combustion studies through experiments and numerical modeling. UCSD contributions are described in a companion communication in this conference. The Princeton effort also addresses the analyses of Fiber Supported Droplet Combustion (FSDC) experiments conducted with the above fuels and collaborative work with others who are investigating droplet combustion in the presence of steady convection. A thorough interpretation of droplet burning behavior for n-heptane and n-decane over a relatively wide range of conditions also involves the influences of sooting on the combustion behavior, and this particular aspect on isolated burning of droplets is under consideration in a collaborative program underway with Drexel University. This collaboration is addressed in another communication at this conference. The one-dimensional, time-dependent, numerical modeling approach that we have continued to evolve for analyzing isolated, quiescent droplet combustion data has been further applied to investigate several facets of isolated droplet burning of simple alcohols, n-heptane, and n-decane. Some of the new results are described below.

  17. Three-dimensional colloidal crystals in liquid crystalline blue phases

    PubMed Central

    Ravnik, Miha; Alexander, Gareth P.; Yeomans, Julia M.; Žumer, Slobodan

    2011-01-01

    Applications for photonic crystals and metamaterials put stringent requirements on the characteristics of advanced optical materials, demanding tunability, high Q factors, applicability in visible range, and large-scale self-assembly. Exploiting the interplay between structural and optical properties, colloidal lattices embedded in liquid crystals (LCs) are promising candidates for such materials. Recently, stable two-dimensional colloidal configurations were demonstrated in nematic LCs. However, the question as to whether stable 3D colloidal structures can exist in an LC had remained unanswered. We show, by means of computer modeling, that colloidal particles can self-assemble into stable, 3D, periodic structures in blue phase LCs. The assembly is based on blue phases providing a 3D template of trapping sites for colloidal particles. The particle configuration is determined by the orientational order of the LC molecules: Specifically, face-centered cubic colloidal crystals form in type-I blue phases, whereas body-centered crystals form in type-II blue phases. For typical particle diameters (approximately 100 nm) the effective binding energy can reach up to a few 100 kBT, implying robustness against mechanical stress and temperature fluctuations. Moreover, the colloidal particles substantially increase the thermal stability range of the blue phases, for a factor of two and more. The LC-supported colloidal structure is one or two orders of magnitude stronger bound than, e.g., water-based colloidal crystals. PMID:21368186

  18. Advancing intercultural competency: Canadian engineering employers' experiences with immigrant engineers

    NASA Astrophysics Data System (ADS)

    Friesen, Marcia; Ingram, Sandra

    2013-05-01

    This paper explores Canadian engineering employers' perceptions of and experiences with internationally educated engineers (recent immigrants to Canada) employed in their organisations for varying lengths of time. Qualitative data were collected from employers using focus group methodology. Findings reflected employers' observations of culturally different behaviours and characteristics in their internationally educated employees, employers' reactions to cultural differences ranging from negative attributions to tolerance, and the implementation of largely ad hoc intra-organisational strategies for managing cultural differences in employer-employee relationships. Findings exposed the lack of corporate intercultural competency in the Canadian engineering profession. Equity and gatekeeping implications are discussed.

  19. Advance Power Technology Experiment for the Starshine 3 Satellite

    NASA Technical Reports Server (NTRS)

    Jenkins, Phillip; Scheiman, David; Wilt, David; Raffaelle, Ryne; Button, Robert; Smith, Mark; Kerslake, Thomas; Miller, Thomas; Bailey, Sheila (Technical Monitor); Hepp, A. (Technical Monitor)

    2001-01-01

    The Starshine 3 satellite will carry several power technology demonstrations. Since Starshine 3 is primarily a passive experiment and does not need electrical power to successfully complete its mission, the requirement for a highly reliable power system is greatly reduced. This creates an excellent opportunity to test new power technologies. Several government and commercial interests have teamed up to provide Starshine 3 with a small power system using state-of-the-art components. Starshine 3 will also fly novel integrated microelectronic power supplies (IWS) for evaluation.

  20. Advanced tokamak physics experiments on DIII-D

    SciTech Connect

    Taylor, T.S.

    1998-12-01

    Significant reductions in the size and cost of a fusion power plant core can be realized if simultaneous improvements in the energy confinement time ({tau}{sub E}) and the plasma pressure (or beta {beta}{sub T} = 2 {mu}{sub 0} < p > /B{sub T}{sup 2}) can be achieved in steady-state conditions with high self driven bootstrap current fraction. In addition, effective power exhaust and impurity and particle control is required. Significant progress has been made in experimentally achieving regimes having the required performance in all of these aspects as well as in developing a theoretical understanding of the underlying physics. The authors have extended the duration of high performance ELMing H-mode plasmas with {beta}{sub N} H{sub iop} {approximately} 10 for 5 {tau}{sub E} ({approximately}1 s) and have demonstrated that core transport barriers can be sustained for the entire 5-s neutral beam duration in L-mode plasmas. Recent DIII-D work has advanced the understanding of improved confinement and internal transport barriers in terms of E x B shear stabilization of micro turbulence. With the aim of current profile control in discharges with negative central magnetic shear, they have demonstrated off-axis electron cyclotron current drive for the first time in a tokamak, finding an efficiency above theoretical expectations. MHD stability has been improved through shape optimization, wall stabilization, and modification of the pressure and current density profiles. Heat flux reduction and improved impurity and particle control have been realized through edge/divertor radiation and understanding and utilization of forced scrape off layer flow and divertor baffling.

  1. Colloidal diffusion over a periodic energy landscape

    NASA Astrophysics Data System (ADS)

    Ma, Xiao-Guang; Lai, Pik-Yin; Tong, Penger

    2014-03-01

    A two-layer colloidal system is developed for the study of colloidal diffusion over a two-dimensional periodic energy landscape. The energy landscape is made from the bottom layer of colloidal spheres forming a honey-comb crystalline pattern above a glass substrate. The corrugated surface of the bottom colloidal crystal provides a gravitational potential field for the diffusing particles in the top layer. The obtained population probability histogram P(x , y) of the diffusing particles is used to fully characterize the energy landscape U(x , y) via the Boltzmann distribution. The dynamical properties of the diffusing particle, such as its escape time tR and diffusion coefficient D are simultaneously measured from the particle's trajectories. The long-time diffusion coefficients D is found to be in good agreement with the theory for all colloidal samples studied. The experiment demonstrates the applications of this newly constructed colloidal energy landscape. *Work supported in part by the Research Grants Council of Hong Kong SAR.

  2. Cotransport of bismerthiazol and montmorillonite colloids in saturated porous media

    NASA Astrophysics Data System (ADS)

    Shen, Chongyang; Wang, Hong; Lazouskaya, Volha; Du, Yichun; Lu, Weilan; Wu, Junxue; Zhang, Hongyan; Huang, Yuanfang

    2015-06-01

    While bismerthiazol [N,N‧-methylene-bis-(2-amino-5-mercapto-1,3,4-thiadiazole)] is one of the most widely used bactericides, the transport of bismerthiazol in subsurface environments is unclear to date. Moreover, natural colloids are ubiquitous in the subsurface environments. The cotransport of bismerthiazol and natural colloids has not been investigated. This study conducted laboratory column experiments to examine the transport of bismerthiazol in saturated sand porous media both in the absence and presence of montmorillonite colloids. Results show that a fraction of bismerthiazol was retained in sand and the retention was higher at pH 7 than at pH 4 and 10. The retention did not change with ionic strength. The retention was attributed to the complex of bismerthiazol with metals/metal oxides on sand surfaces through ligand exchange. The transport of bismerthiazol was enhanced with montmorillonite colloids copresent in the solutions and, concurrently, the transport of montmorillonite colloids was facilitated by the bismerthiazol. The transport of montmorillonite colloids was enhanced likely because the bismerthiazol and the colloids competed for the attachment/adsorption sites on collector surfaces and the presence of bismerthiazol changed the Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies between colloids and collectors. The transport of bismerthiazol was inhibited if montmorillonite colloids were pre-deposited in sand because bismerthiazol could adsorb onto the colloid surfaces. The adsorbed bismerthiazol could be co-remobilized with the colloids from primary minima by decreasing ionic strength. Whereas colloid-facilitated transport of pesticides has been emphasized, our study implies that transport of colloids could also be facilitated by the presence of pesticides.

  3. Tuning Colloid-Interface Interactions by Salt Partitioning.

    PubMed

    Everts, J C; Samin, S; van Roij, R

    2016-08-26

    We show that the interaction of an oil-dispersed colloidal particle with an oil-water interface is highly tunable from attractive to repulsive, either by varying the sign of the colloidal charge via charge regulation or by varying the difference in hydrophilicity between the dissolved cations and anions. In addition, we investigate the yet unexplored interplay between the self-regulated colloidal surface charge distribution with the planar double layer across the oil-water interface and the spherical one around the colloid. Our findings explain recent experiments and have direct relevance for tunable Pickering emulsions. PMID:27610887

  4. Lock and key colloids.

    PubMed

    Sacanna, S; Irvine, W T M; Chaikin, P M; Pine, D J

    2010-03-25

    New functional materials can in principle be created using colloids that self-assemble into a desired structure by means of a programmable recognition and binding scheme. This idea has been explored by attaching 'programmed' DNA strands to nanometre- and micrometre- sized particles and then using DNA hybridization to direct the placement of the particles in the final assembly. Here we demonstrate an alternative recognition mechanism for directing the assembly of composite structures, based on particles with complementary shapes. Our system, which uses Fischer's lock-and-key principle, employs colloidal spheres as keys and monodisperse colloidal particles with a spherical cavity as locks that bind spontaneously and reversibly via the depletion interaction. The lock-and-key binding is specific because it is controlled by how closely the size of a spherical colloidal key particle matches the radius of the spherical cavity of the lock particle. The strength of the binding can be further tuned by adjusting the solution composition or temperature. The composite assemblies have the unique feature of having flexible bonds, allowing us to produce flexible dimeric, trimeric and tetrameric colloidal molecules as well as more complex colloidal polymers. We expect that this lock-and-key recognition mechanism will find wider use as a means of programming and directing colloidal self-assembly. PMID:20336142

  5. The Effect of Background Experience and an Advance Organizer on the Attainment of Certain Science Concepts.

    ERIC Educational Resources Information Center

    McAdaragh, Mary Kathleen

    This study examined the effects of an advance organizer and background experience in science on the attainment of science concepts. Ninth-grade earth science students (N=90) were given the Dubbins Earth Science Test (DEST) and a Science Background Experience Inventory (SBEI) developed by the author. They were then placed into high, medium, and low…

  6. Advanced Undergraduate-Laboratory Experiment on Electron Spin Resonance in Single-Crystal Ruby

    ERIC Educational Resources Information Center

    Collins, Lee A.; And Others

    1974-01-01

    An electron-spin-resonance experiment which has been successfully performed in an advanced undergraduate physics laboratory is described. A discussion of that part of the theory of magnetic resonance necessary for the understanding of the experiment is also provided in this article. (DT)

  7. Postural and Object-Oriented Experiences Advance Early Reaching, Object Exploration, and Means-End Behavior

    ERIC Educational Resources Information Center

    Lobo, Michele A.; Galloway, James C.

    2008-01-01

    The effects of 3 weeks of social (control), postural, or object-oriented experiences on 9- to 21-week-old infants' (N = 42) reaching, exploration, and means-end behaviors were assessed. Coders recorded object contacts, mouthing, fingering, attention, and affect from video. Postural and object-oriented experiences advanced reaching, haptic…

  8. Advanced Global Atmospheric Gases Experiment (AGAGE): MIT Contribution

    NASA Technical Reports Server (NTRS)

    Kurylo, Michael

    2003-01-01

    We describe in detail the instrumentation and calibrations used in the ALE, GAGE and AGAGE experiments and present a history of the majority of the anthropogenic ozone- depleting and climate-forcing gases in air based on these experiments. Beginning in 1978, these three successive automated high frequency in-situ experiments have documented the long-term behavior of the measured concentrations of these gases over the past twenty years, and show both the evolution of latitudinal gradients and the high frequency variability due to sources and circulation. We provide estimates of the long-term trends in total chlorine contained in long- lived halocarbons involved in ozone depletion. We summarize interpretations of these measurements using inverse methods to determine trace gas lifetimes and emissions. Finally, we provide a combined observational and modeled reconstruction of the evolution of chlorocarbons by latitude in the atmosphere over the past sixty years which can be used as boundary conditions for interpreting trapped air in glaciers and oceanic measurements of chlorocarbon tracers of the deep oceanic circulation. Some specific conclusions are: (a) International compliance with the Montreal Protocol is so far resulting in chlorofluorocarbon and chlorocarbon mole fractions comparable to target levels, (b) Mole fractions of total chlorine contained in long-lived halocarbons (CCl2F2, CCl3F, CH3CCl3, CCl4, CHClF2, CCl2FCClF2, CH3Cl, CH2Cl2, CHCl3, CCl2=CCl2) in the lower troposphere reached maximum values of about 3.6 ppb in 1993 and are beginning to slowly decrease in the global lower atmosphere, (c) The chlorofluorocarbons have atmospheric lifetimes consistent with destruction in the stratosphere being their principal removal mechanism, (d) Multi-annual variations in chlorofluorocarbon and chlorocarbon emissions deduced from ALUGAGWAGAGE data are consistent approximately with variations estimated independently from industrial production and sales data where

  9. Colloidal thermoresponsive gel forming hybrids.

    PubMed

    Liu, Ruixue; Tirelli, Nicola; Cellesi, Francesco; Saunders, Brian R

    2010-09-15

    Colloidal hybrids comprise organic and inorganic components and are attracting considerable attention in the literature. Recently, we reported hybrid anisotropic microsheets that formed thermoresponsive gels in polymer solutions [Liu et al., Langmuir, 25, 490, 2009]. Here, we investigate the composition and properties of these hybrid colloids themselves in detail for the first time. Three different cationic PNIPAm (N-isopropylacrylamide) graft copolymers and two inorganic nanoparticle types (laponite and Ludox silica) were used to prepare a range of hybrids. Anisotropic microsheets only formed when laponite particles were added to the copolymer implying directed self-assembly. Aqueous dispersions of the microsheets spontaneously formed gels at room temperature and these gels were thermoresponsive. They represent a new class of gel forming colloid and are termed thermoresponsive gel forming hybrids. The compositions of the hybrids were determined from thermogravimetric analysis and those that gave gel forming behaviour identified. Variable-temperature rheology experiments showed that the elasticity of the gels increased linearly with temperature. The reversibility of the thermally-triggered changes in gel elasticity was investigated. The concentration dependence of the rheology data was well described by elastic percolation scaling theory and the data could be collapsed onto a master curve. The concentration exponent for the elastic modulus was 2.5. The strong attractive interactions that exist between the dispersed gel forming hybrids was demonstrated by the formation of stable thermoresponsive hybrid hydrogels through casting of hybrid dispersions. PMID:20561633

  10. Advancing Successful Physics Majors - The Physics First Year Seminar Experience

    NASA Astrophysics Data System (ADS)

    Deibel, Jason; Petkie, Douglas

    In 2012, the Wright State University physics curriculum introduced a new year-long seminar course required for all new physics majors. The goal of this course is to improve student retention and success via building a community of physics majors and provide them with the skills, mindset, and advising necessary to successfully complete a degree and transition to the next part of their careers. This new course sequence assembles a new cohort of majors annually. To prepare each cohort, students engage in a variety of activities that span from student success skills to more specific physics content while building an entrepreneurial mindset. Students participate in activities including study skills, career night, course planning, campus services, and a department social function. More importantly, students gain exposure to programming, literature searches, data analysis, technical writing, elevator pitches, and experimental design via hands-on projects. This includes the students proposing, designing, and conducting their own experiments. Preliminary evidence indicates increased retention, student success, and an enhanced sense of community among physics undergraduate students, The overall number of majors and students eventually completing their physics degrees has nearly tripled. Associate Professor, Department of Physics.

  11. Recent Results from the Physics of Colloids in Space

    NASA Technical Reports Server (NTRS)

    Weitz, David A.; Bailey, A.; Christianson, R.; Manley, S.; Prasad, V.; Segre, P.; Gasser, U.; Cipelletti, L.; Schoefield, A.; Pusey, P.

    2002-01-01

    The Physics of Colloids in Space is an experiment which flew in the ISS. Data on several different samples of colloidal particles were obtained. They provided unexpected information about the behavior of the samples in microgravity. The data are currently being analyzed. The most recent findings will be discussed in this talk.

  12. Physics of Colloids in Space: Flight Hardware Operations on ISS

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.; Bailey, Arthur E.; Jankovsky, Amy L.; Lorik, Tibor

    2002-01-01

    The Physics of Colloids in Space (PCS) experiment was launched on Space Shuttle STS-100 in April 2001 and integrated into EXpedite the PRocess of Experiments to Space Station Rack 2 on the International Space Station (ISS). This microgravity fluid physics investigation is being conducted in the ISS U.S. Lab 'Destiny' Module over a period of approximately thirteen months during the ISS assembly period from flight 6A through flight 9A. PCS is gathering data on the basic physical properties of simple colloidal suspensions by studying the structures that form. A colloid is a micron or submicron particle, be it solid, liquid, or gas. A colloidal suspension consists of these fine particles suspended in another medium. Common colloidal suspensions include paints, milk, salad dressings, cosmetics, and aerosols. Though these products are routinely produced and used, we still have much to learn about their behavior as well as the underlying properties of colloids in general. The long-term goal of the PCS investigation is to learn how to steer the growth of colloidal structures to create new materials. This experiment is the first part of a two-stage investigation conceived by Professor David Weitz of Harvard University (the Principal Investigator) along with Professor Peter Pusey of the University of Edinburgh (the Co-Investigator). This paper describes the flight hardware, experiment operations, and initial science findings of the first fluid physics payload to be conducted on ISS: The Physics of Colloids in Space.

  13. Advanced Life Support Project: Crop Experiments at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Sager, John C.; Stutte, Gary W.; Wheeler, Raymond M.; Yorio, Neil

    2004-01-01

    Crop production systems provide bioregenerative technologies to complement human crew life support requirements on long duration space missions. Kennedy Space Center has lead NASA's research on crop production systems that produce high value fresh foods, provide atmospheric regeneration, and perform water processing. As the emphasis on early missions to Mars has developed, our research focused on modular, scalable systems for transit missions, which can be developed into larger autonomous, bioregenerative systems for subsequent surface missions. Components of these scalable systems will include development of efficient light generating or collecting technologies, low mass plant growth chambers, and capability to operate in the high energy background radiation and reduced atmospheric pressures of space. These systems will be integrated with air, water, and thermal subsystems in an operational system. Extensive crop testing has been done for both staple and salad crops, but limited data is available on specific cultivar selection and breadboard testing to meet nominal Mars mission profiles of a 500-600 day surface mission. The recent research emphasis at Kennedy Space Center has shifted from staple crops, such as wheat, soybean and rice, toward short cycle salad crops such as lettuce, onion, radish, tomato, pepper, and strawberry. This paper will review the results of crop experiments to support the Exploration Initiative and the ongoing development of supporting technologies, and give an overview of capabilities of the newly opened Space Life Science (SLS) Lab at Kennedy Space Center. The 9662 square m (104,000 square ft) SLS Lab was built by the State of Florida and supports all NASA research that had been performed in Hanger-L. In addition to NASA research, the SLS Lab houses the Florida Space Research Institute (FSRI), responsible for co-managing the facility, and the University of Florida (UF) has established the Space Agriculture and Biotechnology Research and

  14. INTRODUCTION: New trends in simulating colloids and self-assembling systems New trends in simulating colloids and self-assembling systems

    NASA Astrophysics Data System (ADS)

    Foffi, Giuseppe; Kahl, Gerhard

    2010-03-01

    relatively high number of contributions as an indicator that the topics presented at these workshops represent substantial scientific developments. The particular motivation to organize these two workshops came from the fact that experimental work in colloidal physics is advancing rapidly around the globe. In contrast, theoretical and simulation approaches to investigate the wide range of new and surprising physical phenomena of colloidal systems is lagging behind this experimental progress. This is the more deploring since theory and simulation might provide a more profound understanding of many phenomena in soft and bio-related physics, such as phase behaviour, self-assembly strategies, or rheological properties, to name but a few. Furthermore this insight might help to guide experiment to design new colloid-based materials with desired properties. The declared aim of the two workshops was thus to bring together scientists who have contributed in recent time to new developments in colloidal physics and to share and discuss their latest innovations. While CECAM workshops traditionally bring together scientists from the theoretical and simulator communities, from the very beginning the organizers considered it an indispensable necessity to invite experimentalists. And indeed, the organizers are happy to confirm that the participation of experimentalists, theoreticians, and simulators was highly fruitful and mutually inspiring: discussions between all communities did help to understand the possibilities and limitations imposed by experiment, theory, and simulations. Reuniting thus all forces, the workshop did contribute to a deeper understanding in colloidal physics and has helped to address future aspects that might lead to more applied problems of technological relevance. The first workshop, entitled 'Computer Simulation Approaches to Study Self-Assembly: From Patchy Nano-Colloids to Virus Capsides', (organized by Jonathan Doye—University Of Oxford, Ard A Louis

  15. Colloidal Brazil-nut effect in sediments of binary charged suspensions

    NASA Astrophysics Data System (ADS)

    Esztermann, A.; Löwen, H.

    2004-10-01

    Equilibrium sedimentation density profiles of charged binary colloidal suspensions are calculated by computer simulations and density-functional theory. For deionized samples, we predict a colloidal "Brazil nut" effect: heavy colloidal particles sediment on top of the lighter ones provided that their mass per charge is smaller than that of the lighter ones. This effect is verifiable in settling experiments.

  16. Colloidal pen lithography.

    PubMed

    Xue, Mianqi; Cai, Xiaojing; Chen, Ghenfu

    2015-02-01

    Colloidal pen lithography, a low-cost, high-throughput scanning probe contact printing method, has been developed, which is based on self-assembled colloidal arrays embedded in a soft elastomeric stamp. Patterned protein arrays are demonstrated using this method, with a feature size ranging from 100 nm to several micrometers. A brief study into the specificity reorganization of protein gives evidence for the feasibility of this method for writing protein chips. PMID:25288364

  17. INITIAL IRRADIATION OF THE FIRST ADVANCED GAS REACTOR FUEL DEVELOPMENT AND QUALIFICATION EXPERIMENT IN THE ADVANCED TEST REACTOR

    SciTech Connect

    S. Blaine Grover; David A. Petti

    2007-09-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation.

  18. Colloidal deposition and aggregation in the presence of charged collectors

    NASA Astrophysics Data System (ADS)

    Sadri, Behnam; Rajendran, Arvind; Bhattacharjee, Subir; Colloids; complex fluid laboratory Team

    2014-11-01

    The transport of colloidal particles in porous media is of great importance in sub-surface environments. These colloidal particles facilitate transport of contaminants, low-soluble compounds and metals in groundwater. Here, we have studied transport dynamics of colloids inside porous medium using a combination of column experiments and batch studies. Polystyrene latex beads (100 nm), as colloidal agents, and soda lime glass beads, as porous medium, are employed in this work. On the one hand, batch experiments are undertaken to better understand concurrent aggregation and deposition of particles. On the other hand, column experiments are performed to understand the flow induced deposition of colloidal particles in the interstitial voids. Effect of collector surface preparation, pH, colloidal suspension concentration and collector beads mass is studied. Chemical release and shear field are revealed as two significant factors lying behind the coagulation of colloidal particles. These findings help us to better distinguish mechanisms responsible for the transport of colloids inside porous medium. We are collaborators. Behnam Sadri is master of science student while two other professor are supervising his research work.

  19. Statistical thermodynamics of charge-stabilized colloids

    NASA Astrophysics Data System (ADS)

    Torres Valderrama, A.

    2008-06-01

    This thesis is a theoretical study of equilibrium statistical thermodynamic properties of colloidal systems in which electrostatic interactions play a dominant role, namely, charge-stabilized colloidal suspensions. Such systems are fluids consisting of a mixture of a large number of mesoscopic particles and microscopic ions which interact via the Coulomb force, suspended in a molecular fluid. Quantum statistical mechanics is essential to fully understand the properties and stability of such systems. A less fundamental but for many purposes, sufficient description, is provided by classical statistical mechanics. In such approximation the system is considered as composed of a great number of charged classical particles with additional hard-core repulsions. The kinetic energy or momentum integrals become independent Gaussians, and hence their contribution to the free energy can be trivially evaluated. The contribution of the potential energy to the free energy on the other hand, depends upon the configuration of all the particles and becomes highly non-trivial due to the long-range character of the Coulomb force and the extremely different length scales involved in the problem. Using the microscopic model described above, we focus on the calculation of equilibrium thermodynamic properties (response functions), correlations (structure factors), and mechanical properties (forces and stresses), which can be measured in experiments and computed by Monte Carlo simulations. This thesis is divided into three parts. In part I, comprising chapters 2 and 3, we focus on finite-thickness effects in colloidal platelets and rigid planar membranes. In chapter 2 we study electrolyte-mediated interactions between two of such colloidal objects. Several aspects of these interactions are considered including the nature (attractive or repulsive) of the force between the objects, the osmotic properties for different types of surfaces and image charge effects. In part II, which includes

  20. Advanced tracking and data relay experiments study: Multimode transponder experiment equipment

    NASA Technical Reports Server (NTRS)

    Cnossen, R. S.

    1973-01-01

    Plans and implementation concepts were developed for a series of experiments utilizing a Multimode Transponder mounted in an aircraft working either through a spacecraft or directly with a ground station which would simulate a TDRSS user working through the TDRSS. The purpose of the experiments is to determine the best modulation and encoding techniques for combating RFI in discreet bands. The experiments also determine the feasibility and accuracy of range and range rate measurements with the various modulation and encoding techniques. An analysis of the Multimode Transponder and ground support equipment is presented, and the additional equipment required to perform the experiments described above is determined.

  1. A Bubble Mixture Experiment Project for Use in an Advanced Design of Experiments Class

    ERIC Educational Resources Information Center

    Steiner, Stefan H.; Hamada, Michael; White, Bethany J.Giddings; Kutsyy, Vadim; Mosesova, Sofia; Salloum, Geoffrey

    2007-01-01

    This article gives an example of how student-conducted experiments can enhance a course in the design of experiments. We focus on a project whose aim is to find a good mixture of water, soap and glycerin for making soap bubbles. This project is relatively straightforward to implement and understand. At its most basic level the project introduces…

  2. Completion of the first NGNP Advanced Gas Reactor Fuel Irradiation Experiment, AGR-1, in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover; John Maki; David Petti

    2010-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and completed a very successful irradiation in early November 2009. The design of AGR-1 test train and support systems used to monitor and control the experiment during

  3. Human Factors Engineering (HFE) insights for advanced reactors based upon operating experience

    SciTech Connect

    Higgins, J.; Nasta, K.

    1997-01-01

    The NRC Human Factors Engineering Program Review Model (HFE PRM, NUREG-0711) was developed to support a design process review for advanced reactor design certification under 10CFR52. The HFE PRM defines ten fundamental elements of a human factors engineering program. An Operating Experience Review (OER) is one of these elements. The main purpose of an OER is to identify potential safety issues from operating plant experience and ensure that they are addressed in a new design. Broad-based experience reviews have typically been performed in the past by reactor designers. For the HFE PRM the intent is to have a more focussed OER that concentrates on HFE issues or experience that would be relevant to the human-system interface (HSI) design process for new advanced reactors. This document provides a detailed list of HFE-relevant operating experience pertinent to the HSI design process for advanced nuclear power plants. This document is intended to be used by NRC reviewers as part of the HFE PRM review process in determining the completeness of an OER performed by an applicant for advanced reactor design certification. 49 refs.

  4. Advanced photovoltaic experiment, S0014: Preliminary flight results and post-flight findings

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.; Scheiman, David A.

    1992-01-01

    The Advanced Photovoltaic Experiment is a Long Duration Exposure Facility (LDEF) experiment originally designed to provide reference solar cell standards for laboratory measurements as well as to investigate the solar spectrum and the effects of long term exposure of space solar cells to the low earth orbit (LEO) environment. The experiment functioned on-orbit as designed, successfully measuring and recording cell performance and solar insolation data over the first 325 days. The objectives and design of the experiment are presented as well as the preliminary flight results and postflight findings.

  5. Completing the Design of the Advanced Gas Reactor Fuel Development and Qualification Experiments for Irradiation in the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover

    2006-10-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the newly formed Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control for each capsule. The swept gas will also have on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation.

  6. AWAKE, The Advanced Proton Driven Plasma Wakefield Acceleration Experiment at CERN

    NASA Astrophysics Data System (ADS)

    Gschwendtner, E.; Adli, E.; Amorim, L.; Apsimon, R.; Assmann, R.; Bachmann, A.-M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Bingham, R.; Biskup, B.; Bohl, T.; Bracco, C.; Burrows, P. N.; Burt, G.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Cipiccia, S.; Damerau, H.; Deacon, L.; Dirksen, P.; Doebert, S.; Dorda, U.; Farmer, J.; Fedosseev, V.; Feldbaumer, E.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gorn, A. A.; Grulke, O.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Jaroszynski, D.; Jensen, L.; Jolly, S.; Joulaei, A.; Kasim, M.; Keeble, F.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Mandry, S.; Martorelli, R.; Martyanov, M.; Mazzoni, S.; Mete, O.; Minakov, V. A.; Mitchell, J.; Moody, J.; Muggli, P.; Najmudin, Z.; Norreys, P.; Öz, E.; Pardons, A.; Pepitone, K.; Petrenko, A.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Salveter, F.; Savard, N.; Schmidt, J.; Seryi, A.; Shaposhnikova, E.; Sheng, Z. M.; Sherwood, P.; Silva, L.; Soby, L.; Sosedkin, A. P.; Spitsyn, R. I.; Trines, R.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Wei, Y.; Welsch, C. P.; Wing, M.; Xia, G.; Zhang, H.

    2016-09-01

    The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) aims at studying plasma wakefield generation and electron acceleration driven by proton bunches. It is a proof-of-principle R&D experiment at CERN and the world's first proton driven plasma wakefield acceleration experiment. The AWAKE experiment will be installed in the former CNGS facility and uses the 400 GeV/c proton beam bunches from the SPS. The first experiments will focus on the self-modulation instability of the long (rms ~12 cm) proton bunch in the plasma. These experiments are planned for the end of 2016. Later, in 2017/2018, low energy (~15 MeV) electrons will be externally injected into the sample wakefields and be accelerated beyond 1 GeV. The main goals of the experiment will be summarized. A summary of the AWAKE design and construction status will be presented.

  7. Does Water Content or Flow Rate Control Colloid Transport in Unsaturated Porous Media?

    SciTech Connect

    Thorsten Knappenberger; Markus Flury; Earl D. Mattson; James B. Harsh

    2014-03-01

    Mobile colloids can play an important role in contaminant transport in soils: many contaminants exist in colloidal form, and colloids can facilitate transport of otherwise immobile contaminants. In unsaturated soils, colloid transport is, among other factors, affected by water content and flow rate. Our objective was to determine whether water content or flow rate is more important for colloid transport. We passed negatively charged polystyrene colloids (220 nm diameter) through unsaturated sand-filled columns under steady-state flow at different water contents (effective water saturations Se ranging from 0.1 to 1.0, with Se = (? – ?r)/(?s – ?r)) and flow rates (pore water velocities v of 5 and 10 cm/min). Water content was the dominant factor in our experiments. Colloid transport decreased with decreasing water content, and below a critical water content (Se < 0.1), colloid transport was inhibited, and colloids were strained in water films. Pendular ring and water film thickness calculations indicated that colloids can move only when pendular rings are interconnected. The flow rate affected retention of colloids in the secondary energy minimum, with less colloids being trapped when the flow rate increased. These results confirm the importance of both water content and flow rate for colloid transport in unsaturated porous media and highlight the dominant role of water content.

  8. Photoelectrochromism in Tungsten Trioxide Colloidal Solutions

    ERIC Educational Resources Information Center

    Chenthamarakshan, C. R.; Tacconi, N. R. de; Xu, Lucy; Rajeshwar, Krishnan

    2004-01-01

    Photophysical and photochemical properties of semiconductor metal oxide colloids are studied in the context of photoelectrochemical conversion and storage of solar energy. The experiment teaches the instrumental principles of UV-visible spectrophotometry, spectral acquisition and background subtraction strategies and diode array spectrometers.

  9. Motile Fluids: Granular, Colloidal and Living

    NASA Astrophysics Data System (ADS)

    Ramaswamy, Sriram

    2014-03-01

    My talk will present our recent results from theory, simulation and experiment on flocking, swarming and instabilities in diverse realizations of active systems. The findings I will report include: flocking at a distance in vibrated granular monolayers; the active hydrodynamics of self-propelled solids; clusters, asters and oscillations in colloidal chemotaxis. Supported by a J C Bose Fellowship.

  10. Binary Colloidal Alloy Test-5: Phase Separation

    NASA Technical Reports Server (NTRS)

    Lynch, Matthew; Weitz, David A.; Lu, Peter J.

    2008-01-01

    The Binary Colloidal Alloy Test - 5: Phase Separation (BCAT-5-PhaseSep) experiment will photograph initially randomized colloidal samples onboard the ISS to determine their resulting structure over time. This allows the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-PhaseSep studies collapse (phase separation rates that impact product shelf-life); in microgravity the physics of collapse is not masked by being reduced to a simple top and bottom phase as it is on Earth.

  11. Interparticle interactions and polarization effects in colloids

    SciTech Connect

    Hayter, J.B.

    1987-01-01

    The physics of simple colloidal systems is usually dominated by three independent length scales: the particle size, the average interparticle distance, and the range of the interparticle potential. The dispersed particles typically have characteristic dimensions in the range 5 to 100 nm, often with spherical or cylindrical symmetry. Dispersion densities vary over volume fractions ranging from 0.5 to 10/sup -4/, with the corresponding mean interparticle distances ranging from about 1 to 10 diameters (in spherical systems). The interaction potential may be very short ranged (hard sphere), very long ranged (Coulomb or dipolar), or anywhere in between (screened Coulomb), and the correlations exhibited in the dispersion may be gas-like, liquid-like or crystalline, depending on the range of the potential relative to the interparticle distance. This rich phase behavior is responsible for the remarkable importance of colloidal studies in many areas of condensed matter physics and biophysics, but it poses often intractable problems in developing the statistical mechanical descriptions necessary for an understanding of scattering data from colloids. This paper will review the considerable recent progress in this field, in the context of SANS experiments on colloids in which the potentials are dominated by either screened Coulomb or magnetic dipolar interactions; in the case of magnetic colloids (ferrofluids), the use of polarization analysis will also be discussed. 32 refs., 4 figs.

  12. Colloids with continuously tunable surface charge.

    PubMed

    van Ravensteijn, Bas G P; Kegel, Willem K

    2014-09-01

    In this paper, we present a robust way to tune the surface potential of polystyrene colloids without changing the pH, ionic strength, etc. The colloids are composed of a cross-linked polystyrene core and a cross-linked vinylbenzyl chloride layer. Besides the chlorine groups, the particle surface contains sulfate/sulfonate groups (arising from the polymerization initiators) that provide a negative surface potential. Performing a Menschutkin reaction on the surface chlorine groups with tertiary amines allows us to introduce quaternary, positively charged amines. The overall charge on the particles is then determined by the ratio between the sulfate/sulfonate moieties and the quaternary amines. Using this process, we were able to invert the charge in a continuous manner without losing colloidal stability upon passing the isoelectric point. The straightforward reaction mechanism together with the fact that the reaction could be quenched rapidly resulted in a colloidal system in which the ζ potential can be tuned between -80 and 45 mV. As proof of principle, the positively charged particles were used in heterocoagulation experiments with nanometer- and micrometer-sized negatively charged silica particles to create geometrically well-defined colloidal (nano) clusters. PMID:25127340

  13. Advanced Test Reactor (ATR) Facility 10CFR830 Safety Basis Related to Facility Experiments

    SciTech Connect

    Tomberlin, Terry Alan

    2002-06-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Test Reactor (ATR), a DOE Category A reactor, was designed to provide an irradiation test environment for conducting a variety of experiments. The ATR Safety Analysis Report, determined by DOE to meet the requirements of 10 CFR 830, Subpart B, provides versatility in types of experiments that may be conducted. This paper addresses two general types of experiments in the ATR facility and how safety analyses for experiments are related to the ATR safety basis. One type of experiment is more routine and generally represents greater risks; therefore this type of experiment is addressed with more detail in the safety basis. This allows individual safety analyses for these experiments to be more routine and repetitive. The second type of experiment is less defined and is permitted under more general controls. Therefore, individual safety analyses for the second type of experiment tend to be more unique from experiment to experiment. Experiments are also discussed relative to "major modifications" and DOE-STD-1027-92. Application of the USQ process to ATR experiments is also discussed.

  14. Advanced Test Reactor (ATR) Facility 10CFR830 Safety Basis Related to Facility Experiments

    SciTech Connect

    Tomberlin, T.A.

    2002-06-19

    The Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Test Reactor (ATR), a DOE Category A reactor, was designed to provide an irradiation test environment for conducting a variety of experiments. The ATR Safety Analysis Report, determined by DOE to meet the requirements of 10 CFR 830, Subpart B, provides versatility in types of experiments that may be conducted. This paper addresses two general types of experiments in the ATR facility and how safety analyses for experiments are related to the ATR safety basis. One type of experiment is more routine and generally represents greater risks; therefore this type of experiment is addressed with more detail in the safety basis. This allows individual safety analyses for these experiments to be more routine and repetitive. The second type of experiment is less defined and is permitted under more general controls. Therefore, individual safety analyses for the second type of experiment tend to be more unique from experiment to experiment. Experiments are also discussed relative to ''major modifications'' and DOE-STD-1027-92. Application of the USQ process to ATR experiments is also discussed.

  15. Health Care Professionals' Death Attitudes, Experiences, and Advance Directive Communication Behavior

    ERIC Educational Resources Information Center

    Black, Kathy

    2007-01-01

    The study surveyed 135 health care professionals (74 nurses, 32 physicians, and 29 social workers) to examine their personal death attitudes and experiences in relation to their reported advance directive communication practice behavior. Negative correlations were found between collaborating with other health care professionals regarding the…

  16. Understanding Fluorescence Measurements through a Guided-Inquiry and Discovery Experiment in Advanced Analytical Laboratory

    ERIC Educational Resources Information Center

    Wilczek-Vera, Grazyna; Salin, Eric Dunbar

    2011-01-01

    An experiment on fluorescence spectroscopy suitable for an advanced analytical laboratory is presented. Its conceptual development used a combination of the expository and discovery styles. The "learn-as-you-go" and direct "hands-on" methodology applied ensures an active role for a student in the process of visualization and discovery of concepts.…

  17. An Advanced Undergraduate Chemistry Laboratory Experiment Exploring NIR Spectroscopy and Chemometrics

    ERIC Educational Resources Information Center

    Wanke, Randall; Stauffer, Jennifer

    2007-01-01

    An advanced undergraduate chemistry laboratory experiment to study the advantages and hazards of the coupling of NIR spectroscopy and chemometrics is described. The combination is commonly used for analysis and process control of various ingredients used in agriculture, petroleum and food products.

  18. The Effect of Conceptual Advancement in Jazz Music Selections and Jazz Experience on Musicians' Aesthetic Response

    ERIC Educational Resources Information Center

    Coggiola, John C.

    2004-01-01

    This study is an investigation of what musicians consider to be their aesthetic experience with jazz music selections that vary in level of conceptual advancement (melodic complexity during improvised solos). Music major participants (N = 128) were assigned to either the jazz musician (n = 64) or nonjazz musician (n = 64) group. Data were gathered…

  19. Learning to Facilitate Advance Care Planning: The Novice Social Worker's Experience

    ERIC Educational Resources Information Center

    Washington, Karla; Bowland, Sharon; Mueggenburg, Kay; Pederson, Margaret; Otten, Sheila; Renn, Tanya

    2014-01-01

    Professional leaders have identified clear roles for social workers involved in advance care planning (ACP), a facilitated process whereby individuals identify their preferences for future medical care; yet information about effective teaching practices in this area is scant. This study reports on the experiences of 14 social workers who…

  20. Against All Odds: Positive Life Experiences of People with Advanced Amyotrophic Lateral Sclerosis.

    ERIC Educational Resources Information Center

    Young, Jenny M.; McNicoll, Paule

    1998-01-01

    Describes the nature of positive life experiences of 13 people coping exceptionally well while living with advanced amyotrophic lateral sclerosis (ALS), or Lou Gehrig's, disease and the resulting significant physical disabilities. Emerging themes were the use of cognitive reappraisal, reframing, and intellectual stimulation as coping mechanisms;…

  1. DECADE OF EXPERIMENT, THE FUND FOR THE ADVANCEMENT OF EDUCATION 1951-61.

    ERIC Educational Resources Information Center

    MURPHY, JUDITH; VON STOEPHASIUS, RENATA

    IN THE 50'S PUBLIC CONCERN ABOUT AMERICAN EDUCATION, THE INFLUENCE OF SPUTNIK I, AND THE NATIONAL DEFENSE EDUCATION ACT OF 1958 BROUGHT ABOUT MAJOR EDUCATIONAL RESULTS. IN TUNE WITH THESE EVENTS AND ATTITUDES, THE FUND FOR THE ADVANCEMENT OF EDUCATION WAS CREATED IN APRIL 1951 FOR THE PURPOSE OF EXPERIMENTING AND PIONEERING IN EDUCATION.…

  2. Ring-Closing Metathesis: An Advanced Guided-Inquiry Experiment for the Organic Laboratory

    ERIC Educational Resources Information Center

    Schepmann, Hala G.; Mynderse, Michelle

    2010-01-01

    The design and implementation of an advanced guided-inquiry experiment for the organic laboratory is described. Grubbs's second-generation catalyst is used to effect the ring-closing metathesis of diethyl diallylmalonate. The reaction is carried out under an inert atmosphere at room temperature and monitored by argentic TLC. The crude reaction is…

  3. Documenting Student Engagement Using an Intention/Reflection Exercise during an Advanced Pharmacy Practice Experience

    ERIC Educational Resources Information Center

    Fierke, Kerry K.; Lepp, Gardner A.

    2015-01-01

    The article shares the outcomes of a practice called Intention/Reflection (I/R) when applied to a group of ten students in a five-week course involving an international advanced pharmacy practice experience. Developed by the authors and founded on a combination of theoretical principles, this practice is unique because of the blend of formative…

  4. Industrial application of surface and colloid science

    SciTech Connect

    Borgarello, E.

    1995-12-01

    Interfacial phenomena are playing a key role in several industrial processes such as oil production and refining, synthesis of chemicals and catalytic reactions. Eniricerche has gained a quite wide experience in applied colloid science in the last fifteen years working together with the Operating Companies of the ENI group. The main areas of interest have been oil production and transportation, fuel formulation, lubrication, bitumen, detergency, reactions in microemulsions, gels for cosmetics, blood substitutes, and photocatalytic degradation of pollutants in colloidal dispersions. The understanding of the interfacial phenomena occurring at the solid-liquid or at the liquid-liquid interface has been a major contribution to the solution of industrial problems. After a short description of Eniricerche activities in applied colloid science, two examples will be described: the hydroformulation of olefines in a microemulsion and the transportation of heavy oil in an oil-in-water emulsion.

  5. Dynamic Assembly of Magnetic Colloidal Vortices.

    PubMed

    Mohorič, Tomaž; Kokot, Gašper; Osterman, Natan; Snezhko, Alexey; Vilfan, Andrej; Babič, Dušan; Dobnikar, Jure

    2016-05-24

    Magnetic colloids in external time-dependent fields are subject to complex induced many-body interactions governing their self-assembly into a variety of equilibrium and out-of-equilibrium structures such as chains, networks, suspended membranes, and colloidal foams. Here, we report experiments, simulations, and theory probing the dynamic assembly of superparamagnetic colloids in precessing external magnetic fields. Within a range of field frequencies, we observe dynamic large-scale structures such as ordered phases composed of precessing chains, ribbons, and rotating fluidic vortices. We show that the structure formation is inherently coupled to the buildup of torque, which originates from internal relaxation of induced dipoles and from transient correlations among the particles as a result of short-lived chain formation. We discuss in detail the physical properties of the vortex phase and demonstrate its potential in particle-coating applications. PMID:27128501

  6. Targeted delivery of colloids by swimming bacteria

    PubMed Central

    Koumakis, N.; Lepore, A.; Maggi, C.; Di Leonardo, R.

    2013-01-01

    The possibility of exploiting motile microorganisms as tiny propellers represents a fascinating strategy for the transport of colloidal cargoes. However, delivery on target sites usually requires external control fields to steer propellers and trigger cargo release. The need for a constant feedback mechanism prevents the design of compact devices where biopropellers could perform their tasks autonomously. Here we show that properly designed three-dimensional (3D) microstructures can define accumulation areas where bacteria spontaneously and efficiently store colloidal beads. The process is stochastic in nature and results from the rectifying action of an asymmetric energy landscape over the fluctuating forces arising from collisions with swimming bacteria. As a result, the concentration of colloids over target areas can be strongly increased or depleted according to the topography of the underlying structures. Besides the significance to technological applications, our experiments pose some important questions regarding the structure of stationary probability distributions in non-equilibrium systems. PMID:24100868

  7. Colloidal Disorder-Order Transition (CDOT-2)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is an image of a colloidal crystal from the CDOT-2 investigation flown on STS-95. There are so many colloidal particles in this sample that it behaves like a glass. In the laboratory on Earth, the sample remained in an amorphous state, showing no sign of crystal growth. In microgravity the sample crystallized in 3 days, as did the other glassy colloidal samples examined in the CDOT-2 experiment. During the investigation, crystallization occurred in samples that had a volume fraction (number of particles per total volume) larger than the formerly reported glass transition of 0.58. This has great implications for theories of the structural glass transition. These crystals were strong enough to survive space shuttle re-entry and landing.

  8. Fast microbial reduction of ferrihydrite colloids from a soil effluent

    NASA Astrophysics Data System (ADS)

    Fritzsche, Andreas; Bosch, Julian; Rennert, Thilo; Heister, Katja; Braunschweig, Juliane; Meckenstock, Rainer U.; Totsche, Kai U.

    2012-01-01

    Recent studies on the microbial reduction of synthetic iron oxide colloids showed their superior electron accepting property in comparison to bulk iron oxides. However, natural colloidal iron oxides differ in composition from their synthetic counterparts. Besides a potential effect of colloid size, microbial iron reduction may be accelerated by electron-shuttling dissolved organic matter (DOM) as well as slowed down by inhibitors such as arsenic. We examined the microbial reduction of OM- and arsenic-containing ferrihydrite colloids. Four effluent fractions were collected from a soil column experiment run under water-saturated conditions. Ferrihydrite colloids precipitated from the soil effluent and exhibited stable hydrodynamic diameters ranging from 281 (±146) nm in the effluent fraction that was collected first and 100 (±43) nm in a subsequently obtained effluent fraction. Aliquots of these oxic effluent fractions were added to anoxic low salt medium containing diluted suspensions of Geobacter sulfurreducens. Independent of the initial colloid size, the soil effluent ferrihydrite colloids were quickly and completely reduced. The rates of Fe2+ formation ranged between 1.9 and 3.3 fmol h-1 cell-1, and are in the range of or slightly exceeding previously reported rates of synthetic ferrihydrite colloids (1.3 fmol h-1 cell-1), but greatly exceeding previously known rates of macroaggregate-ferrihydrite reduction (0.07 fmol h-1 cell-1). The inhibition of microbial Fe(III) reduction by arsenic is unlikely or overridden by the concurrent enhancement induced by soil effluent DOM. These organic species may have increased the already high intrinsic reducibility of colloidal ferrihydrite owing to quinone-mediated electron shuttling. Additionally, OM, which is structurally associated with the soil effluent ferrihydrite colloids, may also contribute to the higher reactivity due to increasing solubility and specific surface area of ferrihydrite. In conclusion, ferrihydrite

  9. F-18 SRA closeup of nose cap showing Advanced L-Probe Air Data Integration experiment

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This L-shaped probe mounted on the forward fuselage of a modified F-18 Systems Research Aircraft was the focus of an air data collection experiment flown at NASA's Dryden Flight Research Center, Edwards, California. The Advanced L-Probe Air Data Integration (ALADIN) experiment focused on providing pilots with angle-of-attack and angle-of-sideslip information as well as traditional airspeed and altitude data from a single system. For the experiment, the probes--one mounted on either side of the F-18's forward fuselage--were hooked to a series of four transducers, which relayed pressure measurements to an on-board research computer.

  10. Advanced Reactor Licensing: Experience with Digital I&C Technology in Evolutionary Plants

    SciTech Connect

    Wood, RT

    2004-09-27

    This report presents the findings from a study of experience with digital instrumentation and controls (I&C) technology in evolutionary nuclear power plants. In particular, this study evaluated regulatory approaches employed by the international nuclear power community for licensing advanced l&C systems and identified lessons learned. The report (1) gives an overview of the modern l&C technologies employed at numerous evolutionary nuclear power plants, (2) identifies performance experience derived from those applications, (3) discusses regulatory processes employed and issues that have arisen, (4) captures lessons learned from performance and regulatory experience, (5) suggests anticipated issues that may arise from international near-term deployment of reactor concepts, and (6) offers conclusions and recommendations for potential activities to support advanced reactor licensing in the United States.

  11. Reconfigurable multi-scale colloidal assembly on excluded volume patterns

    NASA Astrophysics Data System (ADS)

    Edwards, Tara D.; Yang, Yuguang; Everett, W. Neil; Bevan, Michael A.

    2015-09-01

    The ability to create multi-scale, periodic colloidal assemblies with unique properties is important to emerging applications. Dynamically manipulating colloidal structures via tunable kT-scale attraction can provide the opportunity to create particle-based nano- and microstructured materials that are reconfigurable. Here, we report a novel tactic to obtain reconfigurable, multi-scale, periodic colloidal assemblies by combining thermoresponsive depletant particles and patterned topographical features that, together, reversibly mediate local kT-scale depletion interactions. This method is demonstrated in optical microscopy experiments to produce colloidal microstructures that reconfigure between well-defined ordered structures and disordered fluid states as a function of temperature and pattern feature depth. These results are well described by Monte Carlo simulations using theoretical depletion potentials that include patterned excluded volume. Ultimately, the approach reported here can be extended to control the size, shape, orientation, and microstructure of colloidal assemblies on multiple lengths scales and on arbitrary pre-defined pattern templates.

  12. Predicting colloid transport through saturated porous media: A critical review

    NASA Astrophysics Data System (ADS)

    Molnar, Ian L.; Johnson, William P.; Gerhard, Jason I.; Willson, Clinton S.; O'Carroll, Denis M.

    2015-09-01

    Understanding and predicting colloid transport and retention in water-saturated porous media is important for the protection of human and ecological health. Early applications of colloid transport research before the 1990s included the removal of pathogens in granular drinking water filters. Since then, interest has expanded significantly to include such areas as source zone protection of drinking water systems and injection of nanometals for contaminated site remediation. This review summarizes predictive tools for colloid transport from the pore to field scales. First, we review experimental breakthrough and retention of colloids under favorable and unfavorable colloid/collector interactions (i.e., no significant and significant colloid-surface repulsion, respectively). Second, we review the continuum-scale modeling strategies used to describe observed transport behavior. Third, we review the following two components of colloid filtration theory: (i) mechanistic force/torque balance models of pore-scale colloid trajectories and (ii) approximating correlation equations used to predict colloid retention. The successes and limitations of these approaches for favorable conditions are summarized, as are recent developments to predict colloid retention under the unfavorable conditions particularly relevant to environmental applications. Fourth, we summarize the influences of physical and chemical heterogeneities on colloid transport and avenues for their prediction. Fifth, we review the upscaling of mechanistic model results to rate constants for use in continuum models of colloid behavior at the column and field scales. Overall, this paper clarifies the foundation for existing knowledge of colloid transport and retention, features recent advances in the field, critically assesses where existing approaches are successful and the limits of their application, and highlights outstanding challenges and future research opportunities. These challenges and opportunities

  13. Integration of an Introductory Pharmacy Practice Experience With an Advanced Pharmacy Practice Experience in Adult Internal Medicine

    PubMed Central

    Bird, Matthew L.; Vesta, Kimi S.; Harrison, Donald L.; Dennis, Vincent C.

    2012-01-01

    Objective. To describe the development, implementation, and assessment of an internal medicine introductory pharmacy practice experience (IPPE) that was integrated with an existing advanced pharmacy practice experience (APPE) in internal medicine. Design. A structured IPPE was designed for first-, second-, and third-year pharmacy (P1, P2, and P3) students. Activities for the IPPE were based on the established APPE and the individual learner's educational level. Assessment. Students reported a greater understanding of clinical pharmacists’ roles, increased confidence in their clinical skills, and better preparation for APPEs. Peers viewed the approach as innovative and transferable to other practice settings. Participating faculty members provided a greater number of contact hours compared to traditional one-time site visits. Conclusions. Integrating an IPPE with an existing APPE is an effective and efficient way to provide patient care experiences for students in the P1-P3 years in accordance with accreditation standards. PMID:22544969

  14. Influences of Flow Transients and Porous Medium Heterogeneity on Colloid-Associated Contaminant Transport in the Vadose Zone

    SciTech Connect

    James Saiers

    2006-06-28

    Radionuclides, metals, and dense non-aqueous phase liquids have contaminated about six billion cubic meters of soil at Department of Energy (DOE) sites. The subsurface transport of many of these contaminants is facilitated by colloids (i.e., microscopic, waterborne particles). The first step in the transport of contaminants from their sources to off-site surface water and groundwater is migration through the vadose zone. Developing our understanding of the migration of colloids and colloid-associated contaminants through the vadose zone is critical to assessing and controlling the release of contaminants from DOE sites. In this study, we examined the mobilization, transport, and filtration (retention) of mineral colloids and colloid-associated radionuclides within unsaturated porous media. This investigation involved laboratory column experiments designed to identify properties that affect colloid mobilization and retention and pore-scale visualization experiments designed to elucidate mechanisms that govern these colloid-mass transfer processes. The experiments on colloid mobilization and retention were supplemented with experiments on radionuclide transport through porous media and on radionuclide adsorption to mineral colloids. Observations from all of these experiments – the column and visualization experiments with colloids and the experiments with radionuclides – were used to guide the development of mathematical models appropriate for describing colloids and colloid-facilitated radionuclide transport through the vadose zone.

  15. The Next Generation Nuclear Plant/Advanced Gas Reactor Fuel Irradiation Experiments in the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover

    2009-09-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating eight separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006, and the second experiment (AGR-2) is currently in the design phase. The design of test trains, as well as the support systems and fission product monitoring system that will monitor and control the experiment during irradiation will be discussed. In

  16. Structural color from colloidal glasses

    NASA Astrophysics Data System (ADS)

    Magkiriadou, Sofia

    When a material has inhomogeneities at a lengthscale comparable to the wavelength of light, interference can give rise to structural colors: colors that originate from the interaction of the material's microstructure with light and do not require absorbing dyes. In this thesis we study a class of these materials, called photonic glasses, where the inhomogeneities form a dense and random arrangement. Photonic glasses have angle-independent structural colors that look like those of conventional dyes. However, when this work started, there was only a handful of colors accessible with photonic glasses, mostly hues of blue. We use various types of colloidal particles to make photonic glasses, and we study, both theoretically and experimentally, how the optical properties of these glasses relate to their structure and constituent particles. Based on our observations from glasses of conventional particles, we construct a theoretical model that explains the scarcity of yellow, orange, and red photonic glasses. Guided by this model, we develop novel colloidal systems that allow a higher degree of control over structural color. We assemble glasses of soft, core-shell particles with scattering cores and transparent shells, where the resonant wavelength can be tuned independently of the reflectivity. We then encapsulate glasses of these core-shell particles into emulsion droplets of tunable size; in this system, we observe, for the first time, angle-independent structural colors that cover the entire visible spectrum. To enhance color saturation, we begin experimenting with inverse glasses, where the refractive index of the particles is lower than the refractive index of the medium, with promising results. Finally, based on our theoretical model for scattering from colloidal glasses, we begin an exploration of the color gamut that could be achieved with this technique, and we find that photonic glasses are a promising approach to a new type of long-lasting, non-toxic, and

  17. Advanced tracking and data relay experiments study: Multimode transponder experiment analysis procedure

    NASA Technical Reports Server (NTRS)

    Cnossen, R. S.; Moses, J.

    1973-01-01

    Plans and implementation concepts were developed for utilizing a multimode transponder mounted in an aircraft working either through a spacecraft or directly with a ground station. The purpose would be to determine the best modulation and encoding techniques for combating RFI and multipath propagation and to determine the characteristics of VHF and UHF RFI in discreet bands. The experiments would also determine the feasibility and accuracy of range and range rate measurements with the various modulation and encoding techniques.

  18. Hospitalists caring for patients with advanced cancer: An experience-based guide.

    PubMed

    Koo, Douglas J; Tonorezos, Emily S; Kumar, Chhavi B; Goring, Tabitha N; Salvit, Cori; Egan, Barbara C

    2016-04-01

    Every year, nearly 5 million adults with cancer are hospitalized. Limited evidence suggests that hospitalization of the cancer patient is associated with adverse morbidity and mortality. Hospitalization of the patient with advanced cancer allows for an intense examination of health status in the face of terminal illness and an opportunity for defining goals of care. This experience-based guide reports what is currently known about the topic and outlines a systematic approach to maximizing opportunities, improving quality, and enhancing the well-being of the hospitalized patient with advanced cancer. Journal of Hospital Medicine 2016;11:292-296. © 2015 Society of Hospital Medicine. PMID:26588430

  19. Prospects of Colloidal Copper Chalcogenide Nanocrystals.

    PubMed

    van der Stam, Ward; Berends, Anne C; de Mello Donega, Celso

    2016-03-01

    Over the past few years, colloidal copper chalcogenide nanocrystals (NCs) have emerged as promising alternatives to conventional Cd and Pb chalcogenide NCs. Owing to their wide size, shape, and composition tunability, Cu chalcogenide NCs hold great promise for several applications, such as photovoltaics, lighting and displays, and biomedical imaging. They also offer characteristics that are unparalleled by Cd and Pb chalcogenide NCs, such as plasmonic properties. Moreover, colloidal Cu chalcogenide NCs have low toxicity, potentially lower costs, and excellent colloidal stability. This makes them attractive materials for the large-scale deployment of inexpensive, sustainable, and environmentally benign solution-processed devices. Nevertheless, the synthesis of colloidal Cu chalcogenide NCs, especially that of ternary and quaternary compositions, has yet to reach the same level of mastery as that available for the prototypical Cd chalcogenide based NCs. This review provides a concise overview of this rapidly advancing field, sketching the state of the art and highlighting the key challenges. We discuss recent developments in the synthesis of size-, shape-, and composition-controlled NCs of Cu chalcogenides, with emphasis in strategies to circumvent the limitations arising from the need to precisely balance the reactivities of multiple precursors in synthesizing ternary and quaternary compositions. In this respect, we show that topotactic cation-exchange reactions are a promising alternative route to complex multinary Cu chalcogenide NCs and hetero-NCs, which are not attainable by conventional routes. The properties and potential applications of Cu chalcogenide NCs and hetero-NCs are also addressed. PMID:26684665

  20. Colloidal crystal grain boundary formation and motion

    PubMed Central

    Edwards, Tara D.; Yang, Yuguang; Beltran-Villegas, Daniel J.; Bevan, Michael A.

    2014-01-01

    The ability to assemble nano- and micro- sized colloidal components into highly ordered configurations is often cited as the basis for developing advanced materials. However, the dynamics of stochastic grain boundary formation and motion have not been quantified, which limits the ability to control and anneal polycrystallinity in colloidal based materials. Here we use optical microscopy, Brownian Dynamic simulations, and a new dynamic analysis to study grain boundary motion in quasi-2D colloidal bicrystals formed within inhomogeneous AC electric fields. We introduce “low-dimensional” models using reaction coordinates for condensation and global order that capture first passage times between critical configurations at each applied voltage. The resulting models reveal that equal sized domains at a maximum misorientation angle show relaxation dominated by friction limited grain boundary diffusion; and in contrast, asymmetrically sized domains with less misorientation display much faster grain boundary migration due to significant thermodynamic driving forces. By quantifying such dynamics vs. compression (voltage), kinetic bottlenecks associated with slow grain boundary relaxation are understood, which can be used to guide the temporal assembly of defect-free single domain colloidal crystals. PMID:25139760

  1. Advanced lab initiatives: building on a rich diversity of programs and experiments

    NASA Astrophysics Data System (ADS)

    Peterson, Richard

    2009-04-01

    The intermediate and advanced lab experience plays a critical role in preparing physics undergraduates for a diversity of careers and graduate school options. During the last few years AAPT, APS, and ALPhA (Advanced Laboratory Physics Association - http://www.advlab.org/) have been working together to invigorate these programs and to help network their instructors -- including a 2009 2.5-day advanced lab topical conference at the University of Michigan 7/23-7/25 (http://advlabs.aapt.org/). Project oriented labs incorporating applications in engineering, acoustics, fluids, optical metrology and diagnostics, non-linear dynamics, biophysics, and nanoscience can play a broadly motivating role for students planning on REU or graduate work in applied physics areas. Experimental examples highlighted here include studies of mechanical resonance and shock wave phenomena utilizing holographic, Schlieren, and interferometric diagnostics -- often in conjunction with MATLAB and COMSOL computational work.

  2. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.

  3. Developing Structured-Learning Exercises for a Community Advanced Pharmacy Practice Experience

    PubMed Central

    Thomas, Renee Ahrens

    2006-01-01

    The recent growth in the number of pharmacy schools across the nation has resulted in the need for high-quality community advanced pharmacy practice experience (APPE) sites. A vital part of a student's education, these APPEs should be structured and formalized to provide an environment conducive to student learning. This paper discusses how to use a calendar, structured-learning activities, and scheduled evaluations to develop students' knowledge, skills, and abilities in a community pharmacy setting. PMID:17136164

  4. COLLOIDS. Colloidal matter: Packing, geometry, and entropy.

    PubMed

    Manoharan, Vinothan N

    2015-08-28

    Colloidal particles with well-controlled shapes and interactions are an ideal experimental system for exploring how matter organizes itself. Like atoms and molecules, these particles form bulk phases such as liquids and crystals. But they are more than just crude analogs of atoms; they are a form of matter in their own right, with complex and interesting collective behavior not seen at the atomic scale. Their behavior is affected by geometrical or topological constraints, such as curved surfaces or the shapes of the particles. Because the interactions between the particles are often short-ranged, we can understand the effects of these constraints using geometrical concepts such as packing. The geometrical viewpoint gives us a window into how entropy affects not only the structure of matter, but also the dynamics of how it forms. PMID:26315444

  5. Designed Assembly and Integration of Colloidal Nanocrystals for Device Applications.

    PubMed

    Yang, Jiwoong; Choi, Moon Kee; Kim, Dae-Hyeong; Hyeon, Taeghwan

    2016-02-10

    Colloidal nanocrystals have been intensively studied over the past three decades due to their unique properties that originate, in large part, from their nanometer-scale sizes. For applications in electronic and optoelectronic devices, colloidal nanoparticles are generally employed as assembled nanocrystal solids, rather than as individual particles. Consequently, tailoring 2D patterns as well as 3D architectures of assembled nanocrystals is critical for their various applications to micro- and nanoscale devices. Here, recent advances in the designed assembly, film fabrication, and printing/integration methods for colloidal nanocrystals are presented. The advantages and drawbacks of these methods are compared, and various device applications of assembled/integrated colloidal nanocrystal solids are discussed. PMID:26707709

  6. Advanced Test Reactor In-Canal Ultrasonic Scanner: Experiment Design and Initial Results on Irradiated Plates

    SciTech Connect

    D. M. Wachs; J. M. Wight; D. T. Clark; J. M. Williams; S. C. Taylor; D. J. Utterbeck; G. L. Hawkes; G. S. Chang; R. G. Ambrosek; N. C. Craft

    2008-09-01

    An irradiation test device has been developed to support testing of prototypic scale plate type fuels in the Advanced Test Reactor. The experiment hardware and operating conditions were optimized to provide the irradiation conditions necessary to conduct performance and qualification tests on research reactor type fuels for the RERTR program. The device was designed to allow disassembly and reassembly in the ATR spent fuel canal so that interim inspections could be performed on the fuel plates. An ultrasonic scanner was developed to perform dimensional and transmission inspections during these interim investigations. Example results from the AFIP-2 experiment are presented.

  7. A landmark recognition and tracking experiment for flight on the Shuttle/Advanced Technology Laboratory (ATL)

    NASA Technical Reports Server (NTRS)

    Welch, J. D.

    1975-01-01

    The preliminary design of an experiment for landmark recognition and tracking from the Shuttle/Advanced Technology Laboratory is described. It makes use of parallel coherent optical processing to perform correlation tests between landmarks observed passively with a telescope and previously made holographic matched filters. The experimental equipment including the optics, the low power laser, the random access file of matched filters and the electro-optical readout device are described. A real time optically excited liquid crystal device is recommended for performing the input non-coherent optical to coherent optical interface function. A development program leading to a flight experiment in 1981 is outlined.

  8. Fabrication of anisotropic multifunctional colloidal carriers

    NASA Astrophysics Data System (ADS)

    Jerri, Huda A.

    , lithographed patches have been designed to serve as nanoparticle launching pads to illustrate the behavior of released fluorescent tracer nanoparticles. Finally, experience with electrostatics and nanoparticle coatings was translated to real-world applications by quickly developing and testing naturally-functionalized antimicrobial sand for water clarification. This dissertation comprises many research areas including: colloidal assembly; site-specific functionalizations; polymer and metal particle syntheses and growth; mammalian cell and microbial culture; multilayered functionalizations with nanoparticles, fluorophores, polyelectrolytes, ionic initiators, biomolecules, proteins and bacteria.

  9. An experiment in remote manufacturing using the advanced communications technology satellite

    NASA Technical Reports Server (NTRS)

    Tsatsoulis, Costas; Frost, Victor

    1991-01-01

    The goal of the completed project was to develop an experiment in remote manufacturing that would use the capabilities of the ACTS satellite. A set of possible experiments that could be performed using the Advanced Communications Technology Satellite (ACTS), and which would perform remote manufacturing using a laser cutter and an integrated circuit testing machine are described in detail. The proposed design is shown to be a feasible solution to the offered problem and it takes into consideration the constraints that were placed on the experiment. In addition, we have developed two more experiments that are included in this report: backup of rural telecommunication networks, and remote use of Synthetic Aperture Radar (SAR) data analysis for on-site collection of glacier scattering data in the Antarctic.

  10. The experience of living with advanced-stage cancer: a thematic synthesis of the literature.

    PubMed

    García-Rueda, N; Carvajal Valcárcel, A; Saracíbar-Razquin, M; Arantzamendi Solabarrieta, M

    2016-07-01

    The aim of the study was to understand the experience of people living with advanced-stage cancer through literature. The search included The Cochrane Library, PubMed, PsycInfo, CINAHL and Cuiden. Thirteen studies were included. A qualitative meta-synthesis was conducted. One thread emerged from the thematic synthesis: the desire to live as normally as possible, despite being aware of the proximity of death. Three themes also emerged: "a process that is unique" with its four sub-themes; "support network" and "health context," each of them having two sub-themes. This study concludes that living with advanced-stage cancer is a unique and complex process which has both positive and negative aspects. The review provides a comprehensive view of the experience, which considers the importance of the support network and the health context in which the person lives. In this study, "normalcy" is the adjustment to the new reality and living as closely as possible to the way one lived before the disease, while developing a new relationship with being finite and death. A better understanding of the experience of living with advanced-stage cancer will help health professionals to identify the needs of the patients in order to plan individual, high-quality care. PMID:27297131

  11. Status of the NGNP Fuel Experiment AGR-2 Irradiated in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2), which utilized the same experiment design as well as control and monitoring systems as AGR-1, started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The design of this experiment and support systems will be briefly discussed, followed by the progress and status of the experiment to date.

  12. Colloids and Nucleation

    NASA Technical Reports Server (NTRS)

    Ackerson, Bruce

    1997-01-01

    The objectives of the work funded under this grant were to develop a microphotographic technique and use it to monitor the nucleation and growth of crystals of hard colloidal spheres. Special attention is given to the possible need for microgravity studies in future experiments. A number of persons have been involved in this work. A masters student, Keith Davis, began the project and developed a sheet illumination apparatus and an image processing system for detection and analysis. His work on a segmentation program for image processing was sufficient for his master's research and has been published. A post doctoral student Bernie Olivier and a graduate student Yueming He, who originally suggested the sheet illumination, were funded by another source but along with Keith made photographic series of several samples (that had been made by Keith Davis). Data extraction has been done by Keith, Bernie, Yueming and two undergraduates employed on the grant. Results are published in Langmuir. These results describe the sheet lighting technique as one which illuminates not only the Bragg scattering crystal, but all the crystals. Thus, accurate crystal counts can be made for nucleation rate measurements. The strange crystal length scale reduction, observed in small angle light scattering (SALS) studies, following the initial nucleation and growth period, has been observed directly. The Bragg scattering (and dark) crystal size decreases in the crossover region. This could be an effect due to gravitational forces or due to over- compression of the crystal during growth. Direct observations indicate a complex morphology for the resulting hard sphere crystals. The crystal edges are fairly sharp but the crystals have a large degree of internal structure. This structure is a result of (unstable) growth and not aggregation. As yet unpublished work compares growth exponents data with data obtained by SALS. The nucleation rate density is determined over a broad volume fraction range

  13. Reentrant network formation in patchy colloidal mixtures under gravity

    NASA Astrophysics Data System (ADS)

    de las Heras, Daniel; Treffenstädt, Lucas L.; Schmidt, Matthias

    2016-03-01

    We study a two-dimensional binary mixture of patchy colloids in sedimentation-diffusion equilibrium using Monte Carlo simulation and Wertheim's theory. By tuning the buoyant masses of the colloids we can control the gravity-induced sequence of fluid stacks of differing density and percolation properties. We find complex stacking sequences with up to four layers and reentrant network formation, consistently in simulations and theoretically using only the bulk phase diagram as input. Our theory applies to general patchy colloidal mixtures and is relevant to understanding experiments under gravity.

  14. Does Shining Light on Gold Colloids Influence Aggregation?

    PubMed Central

    Bhattacharya, Susmita; Narasimha, Suda; Roy, Anushree; Banerjee, Soumitro

    2014-01-01

    In this article we revisit the much-studied behavior of self-assembled aggregates of gold colloidal particles. In the literature, the electrostatic interactions, van der Waals interactions, and the change in free energy due to ligand-ligand or ligand-solvent interactions are mainly considered to be the dominating factors in determining the characteristics of the gold aggregates. However, our light scattering and imaging experiments clearly indicate a distinct effect of light in the growth structure of the gold colloidal particles. We attribute this to the effect of a non-uniform distribution of the electric field in aggregated gold colloids under the influence of light. PMID:24909824

  15. Influences of Flow Transients and Porous Medium Heterogeneity on Colloid-Associated Contaminant Transport in the Vadose Zone

    SciTech Connect

    James Saiers; Joseph Ryan

    2006-07-02

    Radionuclides, metals, and dense non-aqueous phase liquids have contaminated about six billion cubic meters of soil at Department of Energy (DOE) sites. The subsurface transport of many of these contaminants is facilitated by colloids (i.e., microscopic, waterborne particles). The first step in the transport of contaminants from their sources to off-site surface water and groundwater is migration through the vadose zone. Developing our understanding of the migration of colloids and colloid-associated contaminants through the vadose zone is critical to assessing and controlling the release of contaminants from DOE sites. In this study, we examined the mobilization, transport, and filtration (retention) of mineral colloids and colloidassociated radionuclides within unsaturated porous media. This investigation involved laboratory column experiments designed to identify properties that affect colloid mobilization and retention and pore-scale visualization experiments designed to elucidate mechanisms that govern these colloid-mass transfer processes. The experiments on colloid mobilization and retention were supplemented with experiments on radionuclide transport through porous media and on radionuclide adsorption to mineral colloids. Observations from all of these experiments – the column and visualization experiments with colloids and the experiments with radionuclides – were used to guide the development of mathematical models appropriate for describing colloids and colloid-facilitated radionuclide transport through the vadose zone.

  16. Colloidal interactions and fouling of NF and RO membranes: a review.

    PubMed

    Tang, Chuyang Y; Chong, T H; Fane, Anthony G

    2011-05-11

    Colloids are fine particles whose characteristic size falls within the rough size range of 1-1000 nm. In pressure-driven membrane systems, these fine particles have a strong tendency to foul the membranes, causing a significant loss in water permeability and often a deteriorated product water quality. There have been a large number of systematic studies on colloidal fouling of reverse osmosis (RO) and nanofiltration (NF) membranes in the last three decades, and the understanding of colloidal fouling has been significantly advanced. The current paper reviews the mechanisms and factors controlling colloidal fouling of both RO and NF membranes. Major colloidal foulants (including both rigid inorganic colloids and organic macromolecules) and their properties are summarized. The deposition of such colloidal particles on an RO or NF membrane forms a cake layer, which can adversely affect the membrane flux due to 1) the cake layer hydraulic resistance and/or 2) the cake-enhanced osmotic pressure. The effects of feedwater compositions, membrane properties, and hydrodynamic conditions are discussed in detail for inorganic colloids, natural organic matter, polysaccharides, and proteins. In general, these effects can be readily explained by considering the mass transfer near the membrane surface and the colloid-membrane (or colloid-colloid) interaction. The critical flux and limiting flux concepts, originally developed for colloidal fouling of porous membranes, are also applicable to RO and NF membranes. For small colloids (diameter≪100 nm), the limiting flux can result from two different mechanisms: 1) the diffusion-solubility (gel formation) controlled mechanism and 2) the surface interaction controlled mechanism. The former mechanism probably dominates for concentrated solutions, while the latter mechanism may be more important for dilute solutions. Future research needs on RO and NF colloidal fouling are also identified in the current paper. PMID:21094487

  17. Collective motion in populations of colloidal robots

    NASA Astrophysics Data System (ADS)

    Bartolo, Denis; Bricard, Antoine; Caussin, Jean-Baptiste; Dauchot, Olivier; Desreumaux, Nicolas

    2014-03-01

    Could the behavior of bacteria swarms, fish schools, and bird flocks be understood within a unified framework? Can one ignore the very details of the interaction mechanisms at the individual level to elucidate how strikingly similar collective motion emerges at the group level in this broad range of motile systems? These seemingly provocative questions have triggered significant advance in the physics and the biology, communities over the last decade. In the physics language these systems, made of motile individuals, can all be though as different realizations of ``active matter.'' In this talk, I will show how to gain more insight into this vivid field using self-propelled colloids as a proxy for motile organism. I will show how to motorize colloidal particles capable of sensing the orientation of their neighbors. Then, I will demonstrate that these archetypal populations display spontaneous transitions to swarming motion, and to global directed motion with very few density and orientation fluctuations.

  18. Colloidal cholesteric liquid crystal in spherical confinement.

    PubMed

    Li, Yunfeng; Jun-Yan Suen, Jeffrey; Prince, Elisabeth; Larin, Egor M; Klinkova, Anna; Thérien-Aubin, Héloïse; Zhu, Shoujun; Yang, Bai; Helmy, Amr S; Lavrentovich, Oleg D; Kumacheva, Eugenia

    2016-01-01

    The organization of nanoparticles in constrained geometries is an area of fundamental and practical importance. Spherical confinement of nanocolloids leads to new modes of packing, self-assembly, phase separation and relaxation of colloidal liquids; however, it remains an unexplored area of research for colloidal liquid crystals. Here we report the organization of cholesteric liquid crystal formed by nanorods in spherical droplets. For cholesteric suspensions of cellulose nanocrystals, with progressive confinement, we observe phase separation into a micrometer-size isotropic droplet core and a cholesteric shell formed by concentric nanocrystal layers. Further confinement results in a transition to a bipolar planar cholesteric morphology. The distribution of polymer, metal, carbon or metal oxide nanoparticles in the droplets is governed by the nanoparticle size and yields cholesteric droplets exhibiting fluorescence, plasmonic properties and magnetic actuation. This work advances our understanding of how the interplay of order, confinement and topological defects affects the morphology of soft matter. PMID:27561545

  19. Colloidal cholesteric liquid crystal in spherical confinement

    PubMed Central

    Li, Yunfeng; Jun-Yan Suen, Jeffrey; Prince, Elisabeth; Larin, Egor M.; Klinkova, Anna; Thérien-Aubin, Héloïse; Zhu, Shoujun; Yang, Bai; Helmy, Amr S.; Lavrentovich, Oleg D.; Kumacheva, Eugenia

    2016-01-01

    The organization of nanoparticles in constrained geometries is an area of fundamental and practical importance. Spherical confinement of nanocolloids leads to new modes of packing, self-assembly, phase separation and relaxation of colloidal liquids; however, it remains an unexplored area of research for colloidal liquid crystals. Here we report the organization of cholesteric liquid crystal formed by nanorods in spherical droplets. For cholesteric suspensions of cellulose nanocrystals, with progressive confinement, we observe phase separation into a micrometer-size isotropic droplet core and a cholesteric shell formed by concentric nanocrystal layers. Further confinement results in a transition to a bipolar planar cholesteric morphology. The distribution of polymer, metal, carbon or metal oxide nanoparticles in the droplets is governed by the nanoparticle size and yields cholesteric droplets exhibiting fluorescence, plasmonic properties and magnetic actuation. This work advances our understanding of how the interplay of order, confinement and topological defects affects the morphology of soft matter. PMID:27561545

  20. Status of the NGNP fuel experiment AGR-2 irradiated in the advanced test reactor

    SciTech Connect

    S. Blaine Grover; David A. Petti

    2014-05-01

    The United States Department of Energy's Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also undergo on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2), which utilized the same experiment design as well as control and monitoring systems as AGR-1, started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The design of this experiment and sup

  1. Colloids at NAPL-Interfaces

    NASA Astrophysics Data System (ADS)

    Baumann, Thomas; Metz, Christian

    2014-05-01

    Non-aqueous phase liquids in subsurface are relevant in the scope of contaminated sites as well as for enhanced oil recovery. In both cases colloids and engineered nanoparticles are applied to increase the efficiency of NAPL removal. Particle tracking experiments using fluoresecent latex beads and opaque particles have been run in micromodels mimicking the pore structure of subsurface media. The results show that the interface between NAPL and water is highly dynamic, especially in its early stage. There is a distinct circular flow pattern at the interface, effectively increasing the interfacial area. Concentration gradients measured with Raman Microspectrometry at low Peclet numbers suggest that the mass transfer of dissolved contaminants from the NAPL into the water is highly affected by the interface dynamics. On the other hand the interfaces themselves are less accessible, which has implications for the remediation of contaminated sites.

  2. Summary of Thermocouple Performance During Advanced Gas Reactor Fuel Irradiation Experiments in the Advanced Test Reactor and Out-of-Pile Thermocouple Testing in Support of Such Experiments

    SciTech Connect

    A. J. Palmer; DC Haggard; J. W. Herter; M. Scervini; W. D. Swank; D. L. Knudson; R. S. Cherry

    2011-07-01

    High temperature gas reactor experiments create unique challenges for thermocouple based temperature measurements. As a result of the interaction with neutrons, the thermoelements of the thermocouples undergo transmutation, which produces a time dependent change in composition and, as a consequence, a time dependent drift of the thermocouple signal. This drift is particularly severe for high temperature platinum-rhodium thermocouples (Types S, R, and B); and tungsten-rhenium thermocouples (Types C and W). For lower temperature applications, previous experiences with type K thermocouples in nuclear reactors have shown that they are affected by neutron irradiation only to a limited extent. Similarly type N thermocouples are expected to be only slightly affected by neutron fluxes. Currently the use of these Nickel based thermocouples is limited when the temperature exceeds 1000°C due to drift related to phenomena other than nuclear irradiation. High rates of open-circuit failure are also typical. Over the past ten years, three long-term Advanced Gas Reactor (AGR) experiments have been conducted with measured temperatures ranging from 700oC – 1200oC. A variety of standard Type N and specialty thermocouple designs have been used in these experiments with mixed results. A brief summary of thermocouple performance in these experiments is provided. Most recently, out of pile testing has been conducted on a variety of Type N thermocouple designs at the following (nominal) temperatures and durations: 1150oC and 1200oC for 2000 hours at each temperature, followed by 200 hours at 1250oC, and 200 hours at 1300oC. The standard Type N design utilizes high purity crushed MgO insulation and an Inconel 600 sheath. Several variations on the standard Type N design were tested, including Haynes 214 alloy sheath, spinel (MgAl2O4) insulation instead of MgO, a customized sheath developed at the University of Cambridge, and finally a loose assembly thermocouple with hard fired alumina

  3. SANS (small-angle neutron scattering) from polymers and colloids

    SciTech Connect

    Hayter, J.B.

    1987-01-01

    Small-angle neutron scattering (SANS) has been remarkably successful in providing detailed quantitative structural information on complex everyday materials, such as polymers and colloids, which are often of considerable industrial as well as academic interest. This paper reviews some recent SANS experiments on polymers and colloids, including ferrofluids, and discusses the use of these apparently complex systems as general physical models of the liquid or solid state.

  4. Colloid Facilitated Transport of Plutonium in Fractured Volcanic Tuff

    NASA Astrophysics Data System (ADS)

    Kersting, A. B.; Zhao, P.; Walensky, J. R.; Roberts, S. K.; Johnson, M. R.; Zavarin, M.; Ramon, E. C.

    2004-12-01

    The transport of low-solubility radionuclides in a colloidal- or colloidal bound state is frequently suspected or observed. Groundwater contaminated with radionuclides associated with underground nuclear tests was collected from several different well locations at the Nevada Test Site (NTS). In each case, the low-levels of plutonium detected in the groundwater were overwhelmingly (>95percent) associated with the colloidal and not the dissolved fraction of the groundwater. The colloidal fractions consisted of secondary minerals such as clays and zeolites. To better understand the mechanisms controlling the potential colloidal transport of plutonium, colloid-facilitated fracture flow laboratory experiments are being conducted. Pseudocolloids consisting of Pu(IV) sorbed to clinoptilolite were combined with a radionuclide solution cocktail consisting of Np, U, Cs, Sr, Sm and 3H and Re (analog to Tc) tracers in NTS-type synthetic groundwater (4.5mM NaHCO3-). The cocktail was injected into a smooth fracture in a volcanic tuff rock core from the NTS and the effluent analyzed. Autoradiography and secondary ion mass spectrometry will be used to understand the mineral -colloid-radionuclide interactions in the fracture volcanic tuff.

  5. Physics Design of the National High-power Advanced Torus Experiment

    SciTech Connect

    Menard, J E; Fu, G -Y; Gorelenkov, N; Kaye, S M; Kramer, G; Maingi, R; Neumeyer, C L; Sabbagh, S A; Soukhanovskii, V A

    2007-07-18

    Moving beyond ITER toward a demonstration power reactor (Demo) will require the integration of stable high fusion gain in steady-state, advanced methods for dissipating very high divertor heat-fluxes, and adherence to strict limits on in-vessel tritium retention. While ITER will clearly address the issue of high fusion gain, and new and planned long-pulse experiments (EAST, JT60-SA, KSTAR, SST-1) will collectively address stable steady-state highperformance operation, none of these devices will adequately address the integrated heat-flux, tritium retention, and plasma performance requirements needed for extrapolation to Demo. Expressing power exhaust requirements in terms of Pheat/R, future ARIES reactors are projected to operate with 60-200MW/m, a Component Test Facility (CTF) or Fusion Development Facility (FDF) for nuclear component testing (NCT) with 40-50MW/m, and ITER 20-25MW/m. However, new and planned long-pulse experiments are currently projected to operate at values of Pheat/R no more than 16MW/m. Furthermore, none of the existing or planned experiments are capable of operating with very high temperature first-wall (Twall = 600-1000C) which may be critical for understanding and ultimately minimizing tritium retention with a reactor-relevant metallic first-wall. The considerable gap between present and near-term experiments and the performance needed for NCT and Demo motivates the development of the concept for a new experiment — the National High-power advanced-Torus eXperiment (NHTX) — whose mission is to study the integration of a fusion-relevant plasma-material interface with stable steady-state high-performance plasma operation.

  6. Colloid migration in fractured media

    SciTech Connect

    Hunt, J.R. . Dept. of Civil Engineering)

    1989-09-15

    Field studies at the Nevada Test Site by researchers at Lawrence Livermore National Laboratory have demonstrated that radionuclides are being transported by colloidal material suspended in groundwater. This observation is counter to most predictions from contaminant transport models because the models assume adsorbed species are immobile. The purpose of this research is to quantify the transport processes for colloidal materials and develop the mechanistic understanding necessary to predict radionuclide transport in fractured media. There were three areas of investigation during this year that have addressed these issues: chemical control of colloid deposition on clean mineral surfaces, colloid accumulation on fracture surfaces, and the influence of deposited colloids on colloid and tracer migration. 7 refs.

  7. MicroTCA and AdvancedTCA equipment evaluation and customization for LHC experiments

    NASA Astrophysics Data System (ADS)

    Di Cosmo, M.; Bobillier, V.; Haas, S.; Joos, M.; Mico, S.; Vasey, F.

    2015-01-01

    The MicroTCA and AdvancedTCA industry standards are candidate modular electronics platforms for the upgrade of the current generation of high energy physics experiments at CERN. The PH-ESE group at CERN launched an xTCA evaluation project with the aim of performing technical evaluations and providing support for commercially available components. Over the past years, different equipment from different vendors has been acquired and evaluated. This paper summarizes our evaluation results of commercial MicroTCA and AdvancedTCA equipment. Special emphasis is put on the component requirements to be defined in view of future equipment procurement. Customized prototypes developed according to these generic specifications are presented for the first time.

  8. Non-equilibrium phenomena in disordered colloidal solids

    NASA Astrophysics Data System (ADS)

    Yunker, Peter

    Colloidal particles are a convenient tool for studying a variety of non-equilibrium phenomena. I will discuss experiments that investigate the aging and non-equilibrium growth of disordered solids. In the first set of experiments, colloidal glasses are rapidly formed to study aging in jammed packings. A colloidal fluid, composed of micron-sized temperature-sensitive pNIPAM particles, is rapidly quenched into a colloidal glass. After the glass is formed, collective rearrangements occur as the glass ages. Particles that undergo irreversible rearrangements, which break nearest-neighbor pairings and allow the glass to relax, are identified. These irreversible rearrangements are accompanied by large clusters of fast moving particles; the number of particles involved in these clusters increases as the glass ages, leading to the slowing of dynamics that is characteristic of aging. In the second set of experiments, we study the role particle shape, and thus, interparticle interaction, plays in the formation of disordered solids with different structural and mechanical properties. Aqueous suspensions of colloidal particles with different shapes evaporate on glass slides. Convective flows during evaporation carry particles from drop center to drop edge, where they accumulate. The resulting particle deposits grow heterogeneously from the edge on the air-water interface. Three distinct growth processes were discovered in the evaporating colloidal suspensions by tuning particle shape-dependent capillary interactions and thus varying the microscopic rules of deposition. Mechanical testing of these particulate deposits reveals that the deposit bending rigidity increases as particles become more anisotropic in shape.

  9. Advanced Laboratory at Texas State University: Error Analysis, Experimental Design, and Research Experience for Undergraduates

    NASA Astrophysics Data System (ADS)

    Ventrice, Carl

    2009-04-01

    Physics is an experimental science. In other words, all physical laws are based on experimentally observable phenomena. Therefore, it is important that all physics students have an understanding of the limitations of certain experimental techniques and the associated errors associated with a particular measurement. The students in the Advanced Laboratory class at Texas State perform three detailed laboratory experiments during the semester and give an oral presentation at the end of the semester on a scientific topic of their choosing. The laboratory reports are written in the format of a ``Physical Review'' journal article. The experiments are chosen to give the students a detailed background in error analysis and experimental design. For instance, the first experiment performed in the spring 2009 semester is entitled Measurement of the local acceleration due to gravity in the RFM Technology and Physics Building. The goal of this experiment is to design and construct an instrument that is to be used to measure the local gravitational field in the Physics Building to an accuracy of ±0.005 m/s^2. In addition, at least one of the experiments chosen each semester involves the use of the research facilities within the physics department (e.g., microfabrication clean room, surface science lab, thin films lab, etc.), which gives the students experience working in a research environment.

  10. Scattering from correlations in colloidal systems

    SciTech Connect

    Hayter, J.B.

    1984-01-01

    Colloidal suspensions typically exhibit spatial correlations over distances of order 10-10/sup 4/ A, corresponding either to the size of individual particles (e.g., polymer chains, surfactant micelles) or to the range of interaction between particles (e.g., charged polymer lattices at low ionic strength). Apart from having fundamental intrinsic interest, such systems are also extremely useful as model systems with which to study, for example, non-Newtonian hydrodynamics, since temporal correlations are generally much longer lived (10/sup -8/-10/sup -3/ sec) than those found in simple atomic or small molecular systems (10/sup -13/-10/sup -10/ sec). Colloids have long been the subject of macroscopic phenomenological research (on rheological properties, for example), but it is only recently that microscopic light, x-ray and neutron scattering techniques have been applied to their study, in large part because of theoretical difficulties in understanding the scattering from dense liquid-like systems of interacting particles. For spherical colloids, such theoretical problems have now been largely overcome, and for anisotropic colloids experimental techniques are being developed which circumvent the intractable theoretical areas. This paper will first review some static light and small-angle neutron scattering (SANS) results on colloidal suspensions, both at equilibrium and in steady-state non-equilibrium situations, and will then discuss some dynamic measurements on polymer solutions and melts made using the neutron spin-echo (NSE) technique. Emphasis is placed on experiments which have a possible counterpart in synchrotron radiation studies. In particular, NSE extends the results of photon correlation spectroscopy (PCS) to larger momentum transfers and shorter time-scales than are available with visible light, and the extension of PCS to short wavelength on a synchrotron source would be of similar fundamental interest.

  11. Qualitative critical incident study of patients’ experiences leading to emergency hospital admission with advanced respiratory illness

    PubMed Central

    Karasouli, Eleni; Munday, Daniel; Bailey, Cara; Staniszewska, Sophie; Hewison, Alistair; Griffiths, Frances

    2016-01-01

    Objectives The high volume of emergency admissions to hospital is a challenge for health systems internationally. Patients with lung cancer and chronic obstructive pulmonary disease (COPD) are frequently admitted to hospital as emergency cases. While the frequency of emergency admission has been investigated, few studies report patient experiences, particularly in relation to the decision-making process prior to emergency admission. We sought to explore patient and carer experiences and those of their healthcare professionals in the period leading up to emergency admission to hospital. Setting 3 UK hospitals located in different urban and rural settings. Design Qualitative critical incident study. Participants 24 patients with advanced lung cancer and 15 with advanced COPD admitted to hospital as emergencies, 20 of their carers and 50 of the health professionals involved in the patients’ care. Results The analysis of patient, carer and professionals’ interviews revealed a detailed picture of the complex processes involved leading to emergency admission to hospital. 3 phases were apparent in this period: self-management of deteriorating symptoms, negotiated decision-making and letting go. These were dynamic processes, characterised by an often rapidly changing clinical condition, uncertainty and anxiety. Patients considered their options drawing on experience, current and earlier advice. Patients tried to avoid admission, reluctantly accepting it, albeit often with a sense of relief, as anxiety increased with worsening symptoms. Conclusions Patients with advanced respiratory illness, and their carers, try to avoid emergency admission, and use logical and complex decision-making before reluctantly accepting it. Clinicians and policy-makers need to understand this complex process when considering how to reduce emergency hospital admissions rather than focusing on identifying and labelling admissions as ‘inappropriate’. PMID:26916687

  12. The perception and experience of gender-based discrimination related to professional advancement among Japanese physicians.

    PubMed

    Yasukawa, Kosuke; Nomura, Kyoko

    2014-01-01

    Previous studies from the US have found that female physicians often experience gender-based discrimination related to professional advancement. In Japan, female physicians are underrepresented in leadership positions but little is known about the prevalence of gender discrimination. We investigated the perception and prevalence of gender-based career obstacles and discrimination among Japanese physicians. The study was based on surveys of alumnae from 13 medical schools and alumni from 3 medical schools. In total, 1,684 female and 808 male physicians completed a self-administered questionnaire (response rate 83% and 58%). More women than men had the perception of gender-based career obstacles for women (77% vs. 55%; p < 0.0001). Women with part-time positions were more likely to have the perception of gender-based career obstacles than women working full-time (OR 1.32, 95% CI: 1.01-1.73). More women than men reported experience of gender discrimination related to professional advancement (21% vs. 3%; p < 0.0001). Factors associated with experience of gender discrimination included age (p < 0.0001), marital status (p < 0.0001), academic positions (p < 0.0001), subspecialty board certification (p = 0.0011), and PhD status (p < 0.0001). Women older than 40 years were more likely to experience gender discrimination compared with younger women (OR 5.77, 95% CI: 1.83-18.24 for women above 50, and OR 3.2, 95% CI: 1.48-7.28 for women between 40 and 49) and women with PhD were more likely to experience gender discrimination (OR 4.23, 95% CI: 1.81-9.89). Our study demonstrated that a significant proportion of Japanese women experienced gender-based discrimination and perceived gender-based career obstacles compared with male physicians. PMID:24477176

  13. Subharmonic Shapiro steps of sliding colloidal monolayers in optical lattices.

    PubMed

    Paronuzzi Ticco, Stella V; Fornasier, Gabriele; Manini, Nicola; Santoro, Giuseppe E; Tosatti, Erio; Vanossi, Andrea

    2016-04-01

    We investigate theoretically the possibility to observe dynamical mode locking, in the form of Shapiro steps, when a time-periodic potential or force modulation is applied to a two-dimensional (2D) lattice of colloidal particles that are dragged by an external force over an optically generated periodic potential. Here we present realistic molecular dynamics simulations of a 2D experimental setup, where the colloid sliding is realized through the motion of soliton lines between locally commensurate patches or domains, and where the Shapiro steps are predicted and analyzed. Interestingly, the jump between one step and the next is seen to correspond to a fixed number of colloids jumping from one patch to the next, across the soliton line boundary, during each ac cycle. In addition to ordinary 'integer' steps, coinciding here with the synchronous rigid advancement of the whole colloid monolayer, our main prediction is the existence of additional smaller 'subharmonic' steps due to localized solitonic regions of incommensurate layers executing synchronized slips, while the majority of the colloids remains pinned to a potential minimum. The current availability and wide parameter tunability of colloid monolayers makes these predictions potentially easy to access in an experimentally rich 2D geometrical configuration. PMID:26933976

  14. Subharmonic Shapiro steps of sliding colloidal monolayers in optical lattices

    NASA Astrophysics Data System (ADS)

    Paronuzzi Ticco, Stella V.; Fornasier, Gabriele; Manini, Nicola; Santoro, Giuseppe E.; Tosatti, Erio; Vanossi, Andrea

    2016-04-01

    We investigate theoretically the possibility to observe dynamical mode locking, in the form of Shapiro steps, when a time-periodic potential or force modulation is applied to a two-dimensional (2D) lattice of colloidal particles that are dragged by an external force over an optically generated periodic potential. Here we present realistic molecular dynamics simulations of a 2D experimental setup, where the colloid sliding is realized through the motion of soliton lines between locally commensurate patches or domains, and where the Shapiro steps are predicted and analyzed. Interestingly, the jump between one step and the next is seen to correspond to a fixed number of colloids jumping from one patch to the next, across the soliton line boundary, during each ac cycle. In addition to ordinary ‘integer’ steps, coinciding here with the synchronous rigid advancement of the whole colloid monolayer, our main prediction is the existence of additional smaller ‘subharmonic’ steps due to localized solitonic regions of incommensurate layers executing synchronized slips, while the majority of the colloids remains pinned to a potential minimum. The current availability and wide parameter tunability of colloid monolayers makes these predictions potentially easy to access in an experimentally rich 2D geometrical configuration.

  15. Treatment experience: locally advanced sarcomas with 15 MeV fast neutrons

    SciTech Connect

    Ornitz, R.; Herskovic, A.; Schell, M.; Fender, F.; Rogers, C.C.

    1980-06-01

    Experience with ten evaluable osseous sarcomas and ten evaluable advanced soft tissue sarcomas treated with neutrons of a mean neutron energy of 15 MeV are described. Neutron irradiation with or without conventional megavoltage radiotherapy is an effective modality in the treatment of these patients. No correlation between response rate and grade or whether fast neutrons alone or combined with megavoltage radiotherapy was noted. Those patients receiving a neutron dose of 2195 neutron plus gamma rads or greater all had a complete response.

  16. ETA-II experiments for determining advanced radiographic capabilities of induction linacs

    SciTech Connect

    Weir, J.T.; Caporaso, G.J.; Clark, J.C.; Kirbie, H.C.; Chen, Y.-J.; Lund, S.M.; Westenskow, G.A.; Paul, A.C

    1997-05-01

    LLNL has proposed a multi-pulsed, multi-line of sight radiographic machine based on induction linac technology to be the core of the advanced hydrotest facility (AHF) being considered by the Department of Energy. In order to test the new technologies being developed for AHF we have recommissioned the Experimental Test Accelerator (ETA II). We will conduct our initial experiments using kickers and large angle bending optics at the ETA II facility. Our current status and our proposed experimental schedule will be presented.

  17. MicroTCA and AdvancedTCA equipment evaluation and developments for LHC experiments

    NASA Astrophysics Data System (ADS)

    Bobillier, V.; Haas, S.; Joos, M.; Mendez, J.; Mico, S.; Vasey, F.

    2016-02-01

    The MicroTCA (MTCA) and AdvancedTCA (ATCA) industry standards have been selected as the platform for many of the current and planned upgrades of the off-detector electronic systems of two of the LHC experiments at CERN. We present a status update from an ongoing project to evaluate commercial MTCA and ATCA components with particular emphasis on infrastructure equipment such as shelves and power-supplies. Shelves customized for use in the existing LHC rack infrastructure have been tested, and electrical and cooling measurements and simulations were performed. In-house developments for hardware platform management will also be shown.

  18. Development of electrical feedback controlled heat pipes and the advanced thermal control flight experiment

    NASA Technical Reports Server (NTRS)

    Bienert, W. B.

    1974-01-01

    The development and characteristics of electrical feedback controlled heat pipes (FCHP) are discussed. An analytical model was produced to describe the performance of the FCHP under steady state and transient conditions. An advanced thermal control flight experiment was designed to demonstrate the performance of the thermal control component in a space environment. The thermal control equipment was evaluated on the ATS-F satellite to provide performance data for the components and to act as a thermal control system which can be used to provide temperature stability of spacecraft components in future applications.

  19. Development and operating experience of a short-period superconducting undulator at the Advanced Photon Source

    NASA Astrophysics Data System (ADS)

    Ivanyushenkov, Y.; Harkay, K.; Abliz, M.; Boon, L.; Borland, M.; Capatina, D.; Collins, J.; Decker, G.; Dejus, R.; Dooling, J.; Doose, C.; Emery, L.; Fuerst, J.; Gagliano, J.; Hasse, Q.; Jaski, M.; Kasa, M.; Kim, S. H.; Kustom, R.; Lang, J. C.; Liu, J.; Moog, E.; Robinson, D.; Sajaev, V.; Schroeder, K.; Sereno, N.; Shiroyanagi, Y.; Skiadopoulos, D.; Smith, M.; Sun, X.; Trakhtenberg, E.; Vasserman, I.; Vella, A.; Xiao, A.; Xu, J.; Zholents, A.; Gluskin, E.; Lev, V.; Mezentsev, N.; Syrovatin, V.; Tsukanov, V.; Makarov, A.; Pfotenhauer, J.; Potratz, D.

    2015-04-01

    A decade-long effort at the Advanced Photon Source (APS) of Argonne National Laboratory (ANL) on development of superconducting undulators culminated in December 2012 with the installation of the first superconducting undulator "SCU0" into Sector 6 of the APS storage ring. The device was commissioned in January 2013 and has been in user operation since. This paper presents the magnetic and cryogenic design of the SCU0 together with the results of stand-alone cold tests. The initial commissioning and characterization of SCU0 as well as its operating experience in the APS storage ring are described.

  20. Hysteresis of colloid retention and release in saturated porous media during transients in solution chemistry.

    PubMed

    Torkzaban, Saeed; Kim, Hyunjung N; Simunek, Jiri; Bradford, Scott A

    2010-03-01

    Saturated packed column and micromodel transport studies were conducted to gain insight on mechanisms of colloid retention and release under unfavorable attachment conditions. The initial deposition of colloids in porous media was found to be a strongly coupled process that depended on solution chemistry and pore space geometry. During steady state chemical conditions, colloid deposition was not a readily reversible process, and micromodel photos indicated that colloids were immobilized in the presence of fluid drag. Upon stepwise reduction in eluting solution ionic strength (IS), a sharp release of colloids occurred in each step which indicates that colloid retention depends on a balance of applied (hydrodynamic) and resisting (adhesive) torques which varied with pore space geometry, surface roughness, and interaction energy. When the eluting fluid IS was reduced to deionized water, the final retention locations occurred near grain-grain contacts, and colloid aggregation was sometimes observed in micromodel experiments. Significant amounts of colloid retention hysteresis with IS were observed in the column experiments, and it depended on the porous medium (glass beads compared with sand), the colloid size (1.1 and 0.5 mum), and on the initial deposition IS. These observations were attributed to weak adhesive interactions that depended on the double layer thickness (e.g., the depth of the secondary minimum and/or nanoscale heterogeneity), colloid mass transfer on the solid phase to regions where the torque and force balances were favorable for retention, the number and extent of grain-grain contacts, and surface roughness. PMID:20136144

  1. Advanced Cosmic-Ray Composition Experiment for Space Station (ACCESS): ACCESS Accommodation Study Report

    NASA Technical Reports Server (NTRS)

    Wilson, Thomas L. (Editor); Wefel, John P. (Editor)

    1999-01-01

    In 1994 NASA Administrator selected the first high-energy particle physics experiment for the Space Station, the Alpha Magnetic Spectrometer (AMS), to place a magnetic spectrometer in Earth orbit and search for cosmic antimatter. A natural consequence of this decision was that NASA would begin to explore cost-effective ways through which the design and implementation of AMS might benefit other promising payload experiments. The first such experiment to come forward was Advanced Cosmic-Ray Composition Experiment for Space Station (ACCESS) in 1996. It was proposed as a new mission concept in space physics to attach a cosmic-ray experiment of weight, volume, and geometry similar to the AMS on the International Space Station (ISS), and replace the latter as its successor when the AMS is returned to Earth. This was to be an extension of NASA's suborbital balloon program, with balloon payloads serving as the precursor flights and heritage for ACCESS. The balloon programs have always been a cost-effective NASA resource since the particle physics instrumentation for balloon and space applications are directly related. The next step was to expand the process, pooling together expertise from various NASA centers and universities while opening up definition of the ACCESS science goals to the international community through the standard practice of peer review. This process is still ongoing, and the accommodation study presented here will discuss the baseline definition of ACCESS as we understand it today.

  2. Near minimum-time maneuvers of the advanced space structures technology research experiment (ASTREX) test article: Theory and experiments

    NASA Technical Reports Server (NTRS)

    Vadali, Srinivas R.; Carter, Michael T.

    1994-01-01

    The Phillips Laboratory at the Edwards Air Force Base has developed the Advanced Space Structures Technology Research Experiment (ASTREX) facility to serve as a testbed for demonstrating the applicability of proven theories to the challenges of spacecraft maneuvers and structural control. This report describes the work performed on the ASTREX test article by Texas A&M University under contract NAS119373 as a part of the Control-Structure Interaction (CSI) Guest Investigator Program. The focus of this work is on maneuvering the ASTREX test article with compressed air thrusters that can be throttled, while attenuating structural excitation. The theoretical foundation for designing the near minimum-time thrust commands is based on the generation of smooth, parameterized optimal open-loop control profiles, and the determination of control laws for final position regulation and tracking using Lyapunov stability theory. Details of the theory, mathematical modeling, model updating, and compensation for the presence of 'real world' effects are described and the experimental results are presented. The results show an excellent match between theory and experiments.

  3. Dipolar colloids in apolar media: direct microscopy of two-dimensional suspensions

    PubMed Central

    Janai, Erez; Cohen, Avner P.; Butenko, Alexander V.; Schofield, Andrew B.; Schultz, Moty; Sloutskin, Eli

    2016-01-01

    Spherical colloids, in an absence of external fields, are commonly assumed to interact solely through rotationally-invariant potentials, u(r). While the presence of permanent dipoles in aqueous suspensions has been previously suggested by some experiments, the rotational degrees of freedom of spherical colloids are typically neglected. We prove, by direct experiments, the presence of permanent dipoles in commonly used spherical poly(methyl methacrylate) (PMMA) colloids, suspended in an apolar organic medium. We study, by a combination of direct confocal microscopy, computer simulations, and theory, the structure and other thermodynamical properties of organic suspensions of colloidal spheres, confined to a two-dimensional (2D) monolayer. Our studies reveal the effects of the dipolar interactions on the structure and the osmotic pressure of these fluids. These observations have far-reaching consequences for the fundamental colloidal science, opening new directions in self-assembly of complex colloidal clusters. PMID:27346611

  4. Dipolar colloids in apolar media: direct microscopy of two-dimensional suspensions

    NASA Astrophysics Data System (ADS)

    Janai, Erez; Cohen, Avner P.; Butenko, Alexander V.; Schofield, Andrew B.; Schultz, Moty; Sloutskin, Eli

    2016-06-01

    Spherical colloids, in an absence of external fields, are commonly assumed to interact solely through rotationally-invariant potentials, u(r). While the presence of permanent dipoles in aqueous suspensions has been previously suggested by some experiments, the rotational degrees of freedom of spherical colloids are typically neglected. We prove, by direct experiments, the presence of permanent dipoles in commonly used spherical poly(methyl methacrylate) (PMMA) colloids, suspended in an apolar organic medium. We study, by a combination of direct confocal microscopy, computer simulations, and theory, the structure and other thermodynamical properties of organic suspensions of colloidal spheres, confined to a two-dimensional (2D) monolayer. Our studies reveal the effects of the dipolar interactions on the structure and the osmotic pressure of these fluids. These observations have far-reaching consequences for the fundamental colloidal science, opening new directions in self-assembly of complex colloidal clusters.

  5. Dipolar colloids in apolar media: direct microscopy of two-dimensional suspensions.

    PubMed

    Janai, Erez; Cohen, Avner P; Butenko, Alexander V; Schofield, Andrew B; Schultz, Moty; Sloutskin, Eli

    2016-01-01

    Spherical colloids, in an absence of external fields, are commonly assumed to interact solely through rotationally-invariant potentials, u(r). While the presence of permanent dipoles in aqueous suspensions has been previously suggested by some experiments, the rotational degrees of freedom of spherical colloids are typically neglected. We prove, by direct experiments, the presence of permanent dipoles in commonly used spherical poly(methyl methacrylate) (PMMA) colloids, suspended in an apolar organic medium. We study, by a combination of direct confocal microscopy, computer simulations, and theory, the structure and other thermodynamical properties of organic suspensions of colloidal spheres, confined to a two-dimensional (2D) monolayer. Our studies reveal the effects of the dipolar interactions on the structure and the osmotic pressure of these fluids. These observations have far-reaching consequences for the fundamental colloidal science, opening new directions in self-assembly of complex colloidal clusters. PMID:27346611

  6. ESA successfully conducts experiment in Advanced Space Robotics on Japanese satellite

    NASA Astrophysics Data System (ADS)

    1999-04-01

    ETS-VII is the latest in NASDA's series of engineering test satellites. It is dedicated to the in-orbit assessment and demonstration of novel technologies in rendez-vous / docking and space robotics. ETS-VII is in fact a pair of satellites, a larger chaser and a smaller target satellite which can be released for the rendez-vous and docking experiments. The larger satellite carries a robot arm with a stretched length of about 2 m, and a set of experimentation equipment to test the robot's capabilities : a task board on which typical robot manipulation activities can be performed and measured, an Orbital Replacement Unit (ORU) to be removed and reinstalled, a truss structure to be erected, an antenna assembly mechanism to be actuated and an advanced robot hand. The ESA experiments concern advanced schemes for planning, commanding, controlling and monitoring the activities of a space robot arm system. One set of experiments tests an operational mode called "interactive autonomy", whereby the robot motions are split into typical "tasks" of medium complexity. Ground operators can interact with the tasks (parameterising, commanding, rescheduling, monitoring, interrupting them as needed), relying on the fact that each task will be autonomously executed using appropriate sensor-based control loops (it having been programmed and extensively verified in advance by simulation). This significantly reduces the amount of data traffic over the spacelink - in fact, ETS-VII offers only a few short communications windows per day. Data from ESA experiments will be used to assess the performance of tasks executed with "interactive autonomy" compared with the more traditional telemanipulation at lower control levels. The second group of experiments concerns vision-based robot control. Using the Japanese-provided on-board vision system (which includes one hand camera and one scene-overview camera), it has been demonstrated that reliable automatic object localisation and grasping can be

  7. Assembly of Colloidal Materials Using Bioadhesive Interactions

    NASA Astrophysics Data System (ADS)

    Hammer, Daniel A.; Hiddessen, Amy L.; Tohver, Valeria; Crocker, John C.; Weitz, David A.

    2002-11-01

    these different crosslinking molecules, we have assembled colloidal materials from different-sized colloidal particles, A and B. In the first sets of experiment, we used high densities of adhesion molecules, and 0.96 micron (A) and 5.5 micron (B) diameter particles. The high density of adhesion molecules means that the structures are kinetically trapped in nonequilibrium configurations. The structure of the suspension can be varied by changing the number ratio of the two types of colloidal particles, NA and NB, where A is the smaller particle. With carbohydrate-selectin or avidin-biotin interactions, large NA/NB leads to the formation of colloidal micelles, with the large center B particle surrounded by many smaller A particles. As the ratio NA/NB decreases, the structures become more extended, approaching the formation of macro-Rouse polymers - extended linear chains where A beads are connected with intervening small B linkers.

  8. Assembly of Colloidal Materials Using Bioadhesive Interactions

    NASA Technical Reports Server (NTRS)

    Hammer, Daniel A.; Hiddessen, Amy L.; Tohver, Valeria; Crocker, John C.; Weitz, David A.

    2002-01-01

    these different crosslinking molecules, we have assembled colloidal materials from different-sized colloidal particles, A and B. In the first sets of experiment, we used high densities of adhesion molecules, and 0.96 micron (A) and 5.5 micron (B) diameter particles. The high density of adhesion molecules means that the structures are kinetically trapped in nonequilibrium configurations. The structure of the suspension can be varied by changing the number ratio of the two types of colloidal particles, NA and NB, where A is the smaller particle. With carbohydrate-selectin or avidin-biotin interactions, large NA/NB leads to the formation of colloidal micelles, with the large center B particle surrounded by many smaller A particles. As the ratio NA/NB decreases, the structures become more extended, approaching the formation of macro-Rouse polymers - extended linear chains where A beads are connected with intervening small B linkers.

  9. Tracking colloid transport in porous media using discrete flow fields and sensitivity of simulated colloid deposition to space discretization.

    PubMed

    Li, Zhelong; Zhang, Dongxiao; Li, Xiqing

    2010-02-15

    Advances in pore structure characterization and lattice-Boltzmann (LB) simulations of flow fields in pore spaces are making mechanistic simulations of colloid transport in real porous media a realistic goal. The primary challenge to reach this goal may be the computational demand of LB flow simulations in discretized porous medium domains at an assemblage scale. In this work, flow fields in simple cubic and dense packing systems were simulated at different discretization resolutions using the LB method. The simulated flow fields were incorporated into to a three-dimensional particle tracking model to simulate colloid transport in the two systems. The simulated colloid deposition tended to become asymptotic at a critical discretization resolution (voxel-grain size ratio = 0.01) at groundwater flow regimes for colloids down to submicrometer level under favorable conditions and down to around 1 microm under unfavorable conditions. The average simulated fluid velocities near grain surfaces were extracted to explain the sensitivities of simulated depositions to space discretization under both conditions. At the critical discretization resolution, current computation capacity would allow flow simulations and particle tracking in assemblage porous medium domains. In addition, particle tracking simulations revealed that colloids may be retained in flow vortices under conditions both favorable and unfavorable for deposition. Colloid retention in flow vortices has been proposed only very recently. Here we provide a mechanistic confirmation to this novel retention process. PMID:20088544

  10. Interactive Web-based Learning Modules Prior to General Medicine Advanced Pharmacy Practice Experiences

    PubMed Central

    Walton, Alison M.; Nisly, Sarah A.

    2015-01-01

    Objective. To implement and evaluate interactive web-based learning modules prior to advanced pharmacy practice experiences (APPEs) on inpatient general medicine. Design. Three clinical web-based learning modules were developed for use prior to APPEs in 4 health care systems. The aim of the interactive modules was to strengthen baseline clinical knowledge before the APPE to enable the application of learned material through the delivery of patient care. Assessment. For the primary endpoint, postassessment scores increased overall and for each individual module compared to preassessment scores. Postassessment scores were similar among the health care systems. The survey demonstrated positive student perceptions of this learning experience. Conclusion. Prior to inpatient general medicine APPEs, web-based learning enabled the standardization and assessment of baseline student knowledge across 4 health care systems. PMID:25995515

  11. Fuel plate stability experiments and analysis for the Advanced Neutron Source

    SciTech Connect

    Swinson, W.F.; Battiste, R.L.; Luttrell, C.R.; Yahr, G.T.

    1993-05-01

    The planned reactor for the Advanced Neutron Source (ANS) will use closely spaced arrays of involute-shaped fuel plates that will be cooled by water flowing through the channels between the plates. There is concern that at certain coolant flow velocities, adjacent plates may deflect and touch, with resulting failure of the plates. Experiments have been conducted at the Oak Ridge National Laboratory to examine this potential phenomenon. Results of the experiments and comparison with analytical predictions are reported. The tests were conducted using full-scale epoxy plate models of the aluminum/uranium silicide ANS involute-shaped fuel plates. Use of epoxy plates and model theory allowed lower flow velocities and pressures to explore the potential failure mechanism. Plate deflections and channel pressures as functions of the flow velocity are examined. Comparisons with mathematical models are noted.

  12. Effects of age, system experience, and navigation technique on driving with an advanced traveler information system.

    PubMed

    Dingus, T A; Hulse, M C; Mollenhauer, M A; Fleischman, R N; McGehee, D V; Manakkal, N

    1997-06-01

    This paper explores the effects of age, system experience, and navigation technique on driving, navigation performance, and safety for drivers who used TravTek, an Advanced Traveler Information System. The first two studies investigated various route guidance configurations on the road in a specially equipped instrumented vehicle with an experimenter present. The third was a naturalistic quasi-experimental field study that collected data unobtrusively from more than 1200 TravTek rental car drivers with no in-vehicle experimenter. The results suggest that with increased experience, drivers become familiar with the system and develop strategies for substantially more efficient and safer use. The results also showed that drivers over age 65 had difficulty driving and navigating concurrently. They compensated by driving slowly and more cautiously. Despite this increased caution, older drivers made more safety-related errors than did younger drivers. The results also showed that older drivers benefited substantially from a well-designed ATIS driver interface. PMID:9302887

  13. An Advanced Pharmacy Practice Experience in a Student-Staffed Medication Therapy Management Call Center

    PubMed Central

    Hall, Anna M.; Roane, Teresa E.; Mistry, Reena

    2012-01-01

    Objective. To describe the implementation of an advanced pharmacy practice experience (APPE) in medication therapy management (MTM) designed to contribute to student pharmacists’ confidence and abilities in providing MTM. Design. Sixty-four student pharmacists provided MTM services during an APPE in a communication and care center. Assessment. Students conducted 1,495 comprehensive medication reviews (CMRs) identifying 6,056 medication-related problems. Ninety-eight percent of the students who completed a survey instrument (52 of 53) following the APPE expressed that they had the necessary knowledge and skills to provide MTM services. Most respondents felt that pharmacist participation in providing Medicare MTM could move the profession of pharmacy forward and that pharmacists will have some role in deciding the specific provisions of the Medicare MTM program (92% and 91%, respectively). Conclusion. Students completing the MTM APPE received patient-centered experiences that supplemented their confidence, knowledge, and skill in providing MTM services in the future. PMID:22919086

  14. Advanced Biasing Experiments on the C-2 Field-Reversed Configuration Device

    NASA Astrophysics Data System (ADS)

    Thompson, Matthew; Korepanov, Sergey; Garate, Eusebio; Yang, Xiaokang; Gota, Hiroshi; Douglass, Jon; Allfrey, Ian; Valentine, Travis; Uchizono, Nolan; TAE Team

    2014-10-01

    The C-2 experiment seeks to study the evolution, heating and sustainment effects of neutral beam injection on field-reversed configuration (FRC) plasmas. Recently, substantial improvements in plasma performance were achieved through the application of edge biasing with coaxial plasma guns located in the divertors. Edge biasing provides rotation control that reduces instabilities and E × B shear that improves confinement. Typically, the plasma gun arcs are run at ~ 10 MW for the entire shot duration (~ 5 ms), which will become unsustainable as the plasma duration increases. We have conducted several advanced biasing experiments with reduced-average-power plasma gun operating modes and alternative biasing cathodes in an effort to develop an effective biasing scenario applicable to steady state FRC plasmas. Early results show that several techniques can potentially provide effective, long-duration edge biasing.

  15. Feasibility of conducting a dynamic helium charging experiment for vanadium alloys in the advanced test reactor

    SciTech Connect

    Tsai, H.; Gomes, I.; Strain, R.V.; Smith, D.L.; Matsui, H.

    1996-10-01

    The feasibility of conducting a dynamic helium charging experiment (DHCE) for vanadium alloys in the water-cooled Advanced Test Reactor (ATR) is being investigated as part of the U.S./Monbusho collaboration. Preliminary findings suggest that such an experiment is feasible, with certain constraints. Creating a suitable irradiation position in the ATR, designing an effective thermal neutron filter, incorporating thermocouples for limited specimen temperature monitoring, and handling of tritium during various phases of the assembly and reactor operation all appear to be feasible. An issue that would require special attention, however, is tritium permeation loss through the capsule wall at the higher design temperatures (>{approx}600{degrees}C). If permeation is excessive, the reduced amount of tritium entering the test specimens would limit the helium generation rates in them. At the lower design temperatures (<{approx}425{degrees}C), sodium, instead of lithium, may have to be used as the bond material to overcome the tritium solubility limitation.

  16. Advanced Concepts, Technologies and Flight Experiments for NASA's Earth Science Enterprise

    NASA Technical Reports Server (NTRS)

    Meredith, Barry D.

    2000-01-01

    Over the last 25 years, NASA Langley Research Center (LaRC) has established a tradition of excellence in scientific research and leading-edge system developments, which have contributed to improved scientific understanding of our Earth system. Specifically, LaRC advances knowledge of atmospheric processes to enable proactive climate prediction and, in that role, develops first-of-a-kind atmospheric sensing capabilities that permit a variety of new measurements to be made within a constrained enterprise budget. These advances are enabled by the timely development and infusion of new, state-of-the-art (SOA), active and passive instrument and sensor technologies. In addition, LaRC's center-of-excellence in structures and materials is being applied to the technological challenges of reducing measurement system size, mass, and cost through the development and use of space-durable materials; lightweight, multi-functional structures; and large deployable/inflatable structures. NASA Langley is engaged in advancing these technologies across the full range of readiness levels from concept, to components, to prototypes, to flight experiments, and on to actual science mission infusion. The purpose of this paper is to describe current activities and capabilities, recent achievements, and future plans of the integrated science, engineering, and technology team at Langley Research Center who are working to enable the future of NASA's Earth Science Enterprise.

  17. [Challenges and opportunities: contributions of the Advanced Practice Nurse in the chronicity. Learning from experiences].

    PubMed

    Appleby, Christine; Camacho-Bejarano, Rafaela

    2014-01-01

    Undoubtedly, our society is facing new economic, political, demographic, social and cultural challenges that require healthcare services able to meet the growing health needs of the population, especially in dealing with chronic conditions. In this new context, some countries such as the United Kingdom have made a firm commitment to develop new models for chronic patients care based on the introduction of new figures of Advanced Practice Nurses, which includes 4 cornerstones of professional practice: advanced clinical skills, clinical management, teaching and research. The implementation of this new figures implies a redefinition of professional competencies and has its own accreditation system and a specific catalogue of services adapted to the population requirements, in order to provide chronic care support from Primary Care settings. This trajectory allows us analysing the process of design and implementation of these new models and the organizational structure where it is integrated. In Spain, there are already experiences in some regions such as Andalucia and the Basque Country, focused on the creation of new advanced nursing roles. At present, it is necessary to consider suitable strategic proposals for the complete development of these models and to achieve the best results in terms of overall health and quality of life of patients with chronic conditions, improving the quality of services and cost-effectiveness through a greater cohesion and performance of healthcare teams towards the sustainability of healthcare services and patient satisfaction. PMID:24468497

  18. An evaporation model of colloidal suspension droplets

    NASA Astrophysics Data System (ADS)

    Sartori, Silvana; Li\\ Nán, Amable; Lasheras, Juan C.

    2009-11-01

    Colloidal suspensions of polymers in water or other solvents are widely used in the pharmaceutical industry to coat tablets with different agents. These allow controlling the rate at which the drug is delivered, taste or physical appearance. The coating is performed by simultaneously spraying and drying the tablets with the colloidal suspension at moderately high temperatures. The spreading of the coating on the pills surface depends on the droplet Webber and Reynolds numbers, angle of impact, but more importantly on the rheological properties of the drop. We present a model for the evaporation of a colloidal suspension droplet in a hot air environment with temperatures substantially lower than the boiling temperature of the carrier fluid. As the liquid vaporizes from the surface, a compacting front advances into the droplet faster than the liquid surface regresses, forming a shell of a porous medium where the particles reach their maximum packing density. While the surface regresses, the evaporation rate is determined by both the rate at which heat is transported to the droplet surface and the rate at which liquid vapor is diffused away from it. This regime continues until the compacting front reaches the center of the droplet, at which point the evaporation rate is drastically reduced.

  19. Physics of Colloids in Space-2 (PCS-2)

    NASA Technical Reports Server (NTRS)

    Sankaran, Subramanian; Gasser, Urs; Manley, Suliana; Valentine, Megan; Prasad, Vikram; Rudhardt, Daniel; Bailey, Arthur; Dinsmore, Anthony; Segre, Phil; Doherty, Michael P.

    2001-01-01

    The Physics of Colloids-2 (PCS-2) experiment is aimed at investigating the basic physical properties of several types of colloidal suspensions. The three broad classes of colloidal systems of interest are binary colloids, colloid-polymer mixtures, and fractal gels. The objective is to understand their phase behavior as well as the kinetics of the phase transitions in the absence of gravity. The nucleation, growth, and morphology characteristics of the crystals and gels that form would be studied using confocal microscopy. These will be observed directly with excellent time resolution, and therefore extensive information about the different phases and their growth mechanisms will be gained. With the laser tweezers, it will be possible to measure the strength of these structures and to modify them in a controlled way, and the spectrophotometer will provide the possibility to probe their optical properties. We believe that this experiment will provide the basis for future 'colloid engineering' in which complicated structures with novel properties (e.g., photonic crystals) will be grown by controlled self-assembly.

  20. Chancellor Water Colloids: Characterization and Radionuclide Associated Transport

    SciTech Connect

    Reimus, Paul William; Boukhalfa, Hakim

    2014-09-26

    Column transport experiments were conducted in which water from the Chancellor nuclear test cavity was transported through crushed volcanic tuff from Pahute Mesa. In one experiment, the cavity water was spiked with solute 137Cs, and in another it was spiked with 239/240Pu(IV) nanocolloids. A third column experiment was conducted with no radionuclide spike at all, although the 137Cs concentrations in the water were still high enough to quantify in the column effluent. The radionuclides strongly partitioned to natural colloids present in the water, which were characterized for size distribution, mass concentration, zeta potential/surface charge, critical coagulation concentration, and qualitative mineralogy. In the spiked water experiments, the unanalyzed portion of the high-concentration column effluent samples were combined and re-injected into the respective columns as a second pulse. This procedure was repeated again for a third injection. Measurable filtration of the colloids was observed after each initial injection of the Chancellor water into the columns, but the subsequent injections (spiked water experiments only) exhibited no apparent filtration, suggesting that the colloids that remained mobile after relatively short transport distances were more resistant to filtration than the initial population of colloids. It was also observed that while significant desorption of 137Cs from the colloids occurred after the first injection in both the spiked and unspiked waters, subsequent injections of the spiked water exhibited much less 137Cs desorption (much greater 137Cs colloid-associated transport). This result suggests that the 137Cs that remained associated with colloids during the first injection represented a fraction that was more strongly adsorbed to the mobile colloids than the initial 137Cs associated with the colloids. A greater amount of the 239/240

  1. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K Hartwell; John B. Walter

    2008-09-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  2. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K. Hartwell; John b. Walter

    2010-10-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  3. Rigorous theoretical framework for particle sizing in turbid colloids using light refraction.

    PubMed

    García-Valenzuela, Augusto; Barrera, Rubén G; Gutierrez-Reyes, Edahí

    2008-11-24

    Using a non-local effective-medium approach, we analyze the refraction of light in a colloidal medium. We discuss the theoretical grounds and all the necessary precautions to design and perform experiments to measure the effective refractive index in dilute colloids. As an application, we show that it is possible to retrieve the size of small dielectric particles in a colloid by measuring the complex effective refractive index and the volume fraction occupied by the particles. PMID:19030060

  4. Advanced MRI techniques to improve our understanding of experience-induced neuroplasticity.

    PubMed

    Tardif, Christine Lucas; Gauthier, Claudine Joëlle; Steele, Christopher John; Bazin, Pierre-Louis; Schäfer, Andreas; Schaefer, Alexander; Turner, Robert; Villringer, Arno

    2016-05-01

    Over the last two decades, numerous human MRI studies of neuroplasticity have shown compelling evidence for extensive and rapid experience-induced brain plasticity in vivo. To date, most of these studies have consisted of simply detecting a difference in structural or functional images with little concern for their lack of biological specificity. Recent reviews and public debates have stressed the need for advanced imaging techniques to gain a better understanding of the nature of these differences - characterizing their extent in time and space, their underlying biological and network dynamics. The purpose of this article is to give an overview of advanced imaging techniques for an audience of cognitive neuroscientists that can assist them in the design and interpretation of future MRI studies of neuroplasticity. The review encompasses MRI methods that probe the morphology, microstructure, function, and connectivity of the brain with improved specificity. We underline the possible physiological underpinnings of these techniques and their recent applications within the framework of learning- and experience-induced plasticity in healthy adults. Finally, we discuss the advantages of a multi-modal approach to gain a more nuanced and comprehensive description of the process of learning. PMID:26318050

  5. ADX: a high field, high power density, Advanced Divertor test eXperiment

    NASA Astrophysics Data System (ADS)

    Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Shiraiwa, S.; Terry, J.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; ADX Team

    2014-10-01

    The MIT PSFC and collaborators are proposing an advanced divertor experiment (ADX) - a tokamak specifically designed to address critical gaps in the world fusion research program on the pathway to FNSF/DEMO. This high field (6.5 tesla, 1.5 MA), high power density (P/S ~ 1.5 MW/m2) facility would utilize Alcator magnet technology to test innovative divertor concepts for next-step DT fusion devices (FNSF, DEMO) at reactor-level boundary plasma pressures and parallel heat flux densities while producing high performance core plasma conditions. The experimental platform would also test advanced lower hybrid current drive (LHCD) and ion-cyclotron range of frequency (ICRF) actuators and wave physics at the plasma densities and magnetic field strengths of a DEMO, with the unique ability to deploy launcher structures both on the low-magnetic-field side and the high-field side - a location where energetic plasma-material interactions can be controlled and wave physics is most favorable for efficient current drive, heating and flow drive. This innovative experiment would perform plasma science and technology R&D necessary to inform the conceptual development and accelerate the readiness-for-deployment of FNSF/DEMO - in a timely manner, on a cost-effective research platform. Supported by DE-FC02-99ER54512.

  6. Some vortical-flow flight experiments on slender aircraft that impacted the advancement of aeronautics

    NASA Astrophysics Data System (ADS)

    Lamar, John E.

    2009-08-01

    This paper highlights the three aerodynamic pillars of aeronautics; namely, theory/CFD, wind-tunnel experiments and flight tests, and notes that at any given time these three are not necessarily at the same level of maturity. After an initial history of these three pillars, the focus narrows to a brief history of some vortical-flow flight experiments on slender aircraft that have impacted the advancement of aeronautics in recent decades. They include the F-106, Concorde, SR-71, light-weight fighters (F-16, F/A-18), and F-16XL. These aircraft share in common the utilization of vortical flow and have flown at transonic speeds during a part of the flight envelope. Due to the vast amount of information from flight and CFD that has recently become available for the F-16XL, this aircraft is highlighted and its results detailed. Lastly, it is interesting to note that, though complicated, vortical flows over the F-16XL aircraft at subsonic speeds can be reliably and generally well-predicted with the current CFD flow solvers. However, these solvers still have some problems in matching flight pressure data at transonic speeds. That this problem has been highlighted is both an advancement in aeronautics and a tempting prize to those who would seek its solution.

  7. Design and Implementation of a Laboratory-Based Drug Design and Synthesis Advanced Pharmacy Practice Experience

    PubMed Central

    Philip, Ashok; Stephens, Mark; Mitchell, Sheila L.

    2015-01-01

    Objective. To provide students with an opportunity to participate in medicinal chemistry research within the doctor of pharmacy (PharmD) curriculum. Design. We designed and implemented a 3-course sequence in drug design or drug synthesis for pharmacy students consisting of a 1-month advanced elective followed by two 1-month research advanced pharmacy practice experiences (APPEs). To maximize student involvement, this 3-course sequence was offered to third-year and fourth-year students twice per calendar year. Assessment. Students were evaluated based on their commitment to the project’s success, productivity, and professionalism. Students also evaluated the course sequence using a 14-item course evaluation rubric. Student feedback was overwhelmingly positive. Students found the experience to be a valuable component of their pharmacy curriculum. Conclusion. We successfully designed and implemented a 3-course research sequence that allows PharmD students in the traditional 4-year program to participate in drug design and synthesis research. Students report the sequence enhanced their critical-thinking and problem-solving skills and helped them develop as independent learners. Based on the success achieved with this sequence, efforts are underway to develop research APPEs in other areas of the pharmaceutical sciences. PMID:25995518

  8. Colloidal Bandpass and Bandgap Filters

    NASA Astrophysics Data System (ADS)

    Yellen, Benjamin; Tahir, Mukarram; Ouyang, Yuyu; Nori, Franco

    2013-03-01

    Thermally or deterministically-driven transport of objects through asymmetric potential energy landscapes (ratchet-based motion) is of considerable interest as models for biological transport and as methods for controlling the flow of information, material, and energy. Here, we provide a general framework for implementing a colloidal bandpass filter, in which particles of a specific size range can be selectively transported through a periodic lattice, whereas larger or smaller particles are dynamically trapped in closed-orbits. Our approach is based on quasi-static (adiabatic) transition in a tunable potential energy landscape composed of a multi-frequency magnetic field input signal with the static field of a spatially-periodic magnetization. By tuning the phase shifts between the input signal and the relative forcing coefficients, large-sized particles may experience no local energy barriers, medium-sized particles experience only one local energy barrier, and small-sized particles experience two local energy barriers. The odd symmetry present in this system can be used to nudge the medium-sized particles along an open pathway, whereas the large or small beads remain trapped in a closed-orbit, leading to a bandpass filter, and vice versa for a bandgap filter. NSF CMMI - 0800173, Youth 100 Scholars Fund

  9. Magnetofluidic Tweezing of Nonmagnetic Colloids.

    PubMed

    Timonen, Jaakko V I; Demirörs, Ahmet F; Grzybowski, Bartosz A

    2016-05-01

    Magnetofluidic tweezing based on negative magnetophoresis and microfabricated core-shell magnetic microtips allows controlled on-demand assembly of colloids and microparticles into various static and dynamic structures such as colloidal crystals (as shown for 3.2 μm silica particles). PMID:26990182

  10. Dense colloidal fluids form denser amorphous sediments

    PubMed Central

    Liber, Shir R.; Borohovich, Shai; Butenko, Alexander V.; Schofield, Andrew B.; Sloutskin, Eli

    2013-01-01

    We relate, by simple analytical centrifugation experiments, the density of colloidal fluids with the nature of their randomly packed solid sediments. We demonstrate that the most dilute fluids of colloidal hard spheres form loosely packed sediments, where the volume fraction of the particles approaches in frictional systems the random loose packing limit, φRLP = 0.55. The dense fluids of the same spheres form denser sediments, approaching the so-called random close packing limit, φRCP = 0.64. Our experiments, where particle sedimentation in a centrifuge is sufficiently rapid to avoid crystallization, demonstrate that the density of the sediments varies monotonically with the volume fraction of the initial suspension. We reproduce our experimental data by simple computer simulations, where structural reorganizations are prohibited, such that the rate of sedimentation is irrelevant. This suggests that in colloidal systems, where viscous forces dominate, the structure of randomly close-packed and randomly loose-packed sediments is determined by the well-known structure of the initial fluids of simple hard spheres, provided that the crystallization is fully suppressed. PMID:23530198

  11. Colloid Transport and Surface-Subsurface Exchange in an Acid Mine Drainage-Impacted Stream

    NASA Astrophysics Data System (ADS)

    Norvell, A. S.; Ryan, J. N.; Ren, J.; McKnight, D. M.

    2010-12-01

    Colloidal particles may provide an important control on the mobility of contaminants of concern; e.g., metals introduced into a stream from an acid mine drainage. In order to examine colloidal transport and surface-subsurface exchange, we injected synthesized ferrihydrite colloids along with a conservative tracer, bromide, into Lefthand Creek, a stream contaminated by acid mine drainage in northwestern Boulder County, Colorado. The ferrihydrite colloids were co-precipitated with yttrium to form yttrium-labelled colloids so that we could differentiate them from environmental colloids. Yttrium was measured in samples collected from the surface water and the hyporheic zone. The hyporheic zone samples were collected from a series of mini-piezometers embedded up to 1 m in depth and over a 61 m reach of the stream. A one-dimensional transient storage model (OTIS-P) was used to quantify parameters describing the transport of the conservative tracer and the colloids. Approximately 20% of the colloidal mass was lost over the 61 m reach. The loss of colloids is attributed to deposition in the shallow hyporheic zone. Laboratory column experiments demonstrated that the stream bed sediments effectively remove colloids from suspension at the pH, ionic strength, and dissolved organic matter concentration conditions occurring in Lefthand Creek.

  12. Exchangeable Colloidal AFM Probes for the Quantification of Irreversible and Long-Term Interactions

    PubMed Central

    Dörig, Pablo; Ossola, Dario; Truong, Anh Minh; Graf, Monika; Stauffer, Flurin; Vörös, János; Zambelli, Tomaso

    2013-01-01

    An original method is presented to study single-colloid interaction with a substrate in liquid environment. Colloids, either in solution or adsorbed on a surface, are fixed by suction against the aperture of a microchanneled atomic force microscopy cantilever. Their adhesion to the substrate is measured, followed by their release via a short overpressure surge. Such colloid exchange procedure allows for 1), the quick variation of differently functionalized colloids within the same experiment; 2), the investigation of long-term interactions by leaving the colloids on a surface for a defined time before detaching them; and 3), the inspection of irreversible interactions. After validation of the method by reproducing literature results obtained with traditional colloidal atomic force microscopy, the serial use of colloids with different surface functionalization was shown on a micropatterned surface. Finally, concanavalin A-coated colloids were allowed to adsorb on human embryonic kidney cells and then detached one by one. The adhesion between cells and colloids was up to 60 nN, whereas individual cells adhered with 20 nN to the glass substrate. A cellular elastic modulus of 0.8 kPa was determined using the attached colloid as indenter. PMID:23870267

  13. Advancing Explosion Source Theory through Experimentation: Results from Seismic Experiments Since the Moratorium on Nuclear Testing

    NASA Astrophysics Data System (ADS)

    Bonner, J. L.; Stump, B. W.

    2011-12-01

    On 23 September 1992, the United States conducted the nuclear explosion DIVIDER at the Nevada Test Site (NTS). It would become the last US nuclear test when a moratorium ended testing the following month. Many of the theoretical explosion seismic models used today were developed from observations of hundreds of nuclear tests at NTS and around the world. Since the moratorium, researchers have turned to chemical explosions as a possible surrogate for continued nuclear explosion research. This talk reviews experiments since the moratorium that have used chemical explosions to advance explosion source models. The 1993 Non-Proliferation Experiment examined single-point, fully contained chemical-nuclear equivalence by detonating over a kiloton of chemical explosive at NTS in close proximity to previous nuclear explosion tests. When compared with data from these nearby nuclear explosions, the regional and near-source seismic data were found to be essentially identical after accounting for different yield scaling factors for chemical and nuclear explosions. The relationship between contained chemical explosions and large production mining shots was studied at the Black Thunder coal mine in Wyoming in 1995. The research led to an improved source model for delay-fired mining explosions and a better understanding of mining explosion detection by the International Monitoring System (IMS). The effect of depth was examined in a 1997 Kazakhstan Depth of Burial experiment. Researchers used local and regional seismic observations to conclude that the dominant mechanism for enhanced regional shear waves was local Rg scattering. Travel-time calibration for the IMS was the focus of the 1999 Dead Sea Experiment where a 10-ton shot was recorded as far away as 5000 km. The Arizona Source Phenomenology Experiments provided a comparison of fully- and partially-contained chemical shots with mining explosions, thus quantifying the reduction in seismic amplitudes associated with partial

  14. Colloidal nanocrystals for quality lighting and displays: milestones and recent developments

    NASA Astrophysics Data System (ADS)

    Erdem, Talha; Demir, Hilmi Volkan

    2016-06-01

    Recent advances in colloidal synthesis of nanocrystals have enabled high-quality high-efficiency light-emitting diodes, displays with significantly broader color gamut, and optically-pumped lasers spanning the whole visible regime. Here we review these colloidal platforms covering the milestone studies together with recent developments. In the review, we focus on the devices made of colloidal quantum dots (nanocrystals), colloidal quantum rods (nanorods), and colloidal quantum wells (nanoplatelets) as well as those of solution processed perovskites and phosphor nanocrystals. The review starts with an introduction to colloidal nanocrystal photonics emphasizing the importance of colloidal materials for light-emitting devices. Subsequently,we continue with the summary of important reports on light-emitting diodes, in which colloids are used as the color converters and then as the emissive layers in electroluminescent devices. Also,we review the developments in color enrichment and electroluminescent displays. Next, we present a summary of important reports on the lasing of colloidal semiconductors. Finally, we summarize and conclude the review presenting a future outlook.

  15. Colloidal nanocrystal synthesis and the organic-inorganicinterface

    SciTech Connect

    Yin, Yadong; Alivisatos, A. Paul

    2005-05-12

    Colloidal nanocrystals are nanometer-sized, solution-grown inorganic particles stabilized by a layer of surfactants attached to their surface. The inorganic cores exhibit useful properties controlled by composition as well as size and shape, while the surfactant coating ensures that these structures are easy to fabricate and process. It is this combination of features that makes colloidal nanocrystals attractive and promising building blocks for advanced materials and devices. But their full potential can only be exploited if we achieve exquisite control over their composition, size, shape, crystal structure and surface properties. Here we review what is known about nanocrystal growth and outline strategies for controlling it.

  16. Plant Growth Experiments in Zeoponic Substrates: Applications for Advanced Life Support Systems

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Gruener, J. E.; Henderson, K. E.; Steinberg, S. L.; Barta, D. J.; Galindo, C.; Henninger, D. L.

    2001-01-01

    A zeoponic plant-growth system is defined as the cultivation of plants in artificial soils, which have zeolites as a major component (Allen and Ming, 1995). Zeolites are crystalline, hydrated aluminosilicate minerals that have the ability to exchange constituent cations without major change of the mineral structure. Recently, zeoponic systems developed at the National Aeronautics and Space Administration (NASA) slowly release some (Allen et at., 1995) or all of the essential plant-growth nutrients (Ming et at., 1995). These systems have NH4- and K-exchanged clinoptilolite (a natural zeolite) and either natural or synthetic apatite (a calcium phosphate mineral). For the natural apatite system, Ca and P were made available to the plant by the dissolution of apatite. Potassium and NH4-N were made available by ion-exchange reactions involving Ca(2+) from apatite dissolution and K(+) and NH4(+) on zeolitic exchange sites. In addition to NH4-N, K, Ca, and P, the synthetic apatite system also supplied Mg, S, and other micronutrients during dissolution (Figure 1). The overall objective of this research task is to develop zeoponic substrates wherein all plant growth nutrients are supplied by the plant growth medium for several growth seasons with only the addition of water. The substrate is being developed for plant growth in Advanced Life Support (ALS) testbeds (i.e., BioPLEX) and microgravity plant growth experiments. Zeoponic substrates have been used for plant growth experiments on two Space Shuttle flight experiments (STS-60; STS-63; Morrow et aI., 1995). These substrates may be ideally suited for plant growth experiments on the International Space Station and applications in ALS testbeds. However, there are several issues that need to be resolved before zeoponics will be the choice substrate for plant growth experiments in space. The objective of this paper is to provide an overview on recent research directed toward the refinement of zeoponic plant growth substrates.

  17. Approaches to separations using silica colloidal membranes

    NASA Astrophysics Data System (ADS)

    Ignacio-de Leon, Patricia Anne Argana

    This thesis describes the synthesis and properties of free-standing nanoporous silica colloidal membranes where the molecular transport is controlled on the basis of size, charge, and chiral selectivity. To achieve this, free-standing membranes were prepared from colloidal solutions of silica nanospheres and the nanopore size and surface functionality were varied. First, Au-coated membranes were prepared and the transport of neutral and charged small molecules through Au-coated silica colloidal membranes modified with poly(methacrylic acid) was studied. Polymer length was controlled by polymerization time to produce pH- and ion-responsive brushes inside the nanopores. By monitoring the flux of a diffusing species, it was demonstrated that the polyelectrolyte brush undergoes swelling and collapse when the pH is increased and decreased, respectively. We also observed an expansion and contraction in the absence and presence of counterions, respectively. We also studied the transport of enantiomers of a chiral dye molecule through silica colloidal membranes with attached chiral moieties. We used small molecules and polymers of amino acid derivatives and chiral calixarenes capable of chiral recognition as a result of stereochemically dependent noncovalent interactions with the diffusing molecule. We found that the selectivity remains approximately the same for membranes modified with small molecules and with polymers. This suggests that enantiopermselectivity depends primarily on the strength of noncovalent interactions rather than the availability of recognition sites. Next, the transport of various generations of dendrimers through silica colloidal membranes was studied in a proof-of-concept experiment to demonstrate the size-selectivity of our materials. Smaller dendrimers were found to diffuse faster and selectivity is improved by using smaller nanopores. Finally, the transport of proteins through silica colloidal membranes was studied as a function of nanopore size

  18. Introductory and Advanced Pharmacy Practice Experiences Within Campus-based Influenza Clinics

    PubMed Central

    Johnson, Eric J.; Hagemann, Tracy M.

    2013-01-01

    Objective. To describe the development, implementation, and assessment of an introductory and an advanced pharmacy practice experience (IPPE and APPE) integrated within campus-based influenza clinics. Design. The influenza clinics were designed to incorporate the learning objectives for the IPPE and APPE, and included preparatory sessions, online learning, and direct patient interactions tailored to the appropriate education level of the learner. Assessment. The clinics provided influenza vaccinations to 2,292 and 2,877 individuals in 2010 and 2011, respectively. The clinics allowed for experiential education of 39 students earning a total of 467 IPPE and APPE hours in 2010 and 58 students earning a total of 656 IPPE and APPE hours in 2011. Third-year students were assessed before and after completing the IPPE, and improvement was seen in knowledge and self-ratings of perceptions and attitudes toward administering immunizations. Conclusions. Integrating pharmacy practice experiences within campus-based influenza clinics was an effective way to provide students with direct patient care experience and preventive health services knowledge. PMID:23610479

  19. Mechanical Design and Development of TES Bolometer Detector Arrays for the Advanced ACTPol Experiment

    NASA Technical Reports Server (NTRS)

    Ward, Jonathan T.; Austermann, Jason; Beall, James A.; Choi, Steve K.; Crowley, Kevin T.; Devlin, Mark J.; Duff, Shannon M.; Gallardo, Patricio M.; Henderson, Shawn W.; Ho, Shuay-Pwu Patty; Hilton, Gene; Hubmayr, Johannes; Khavari, Niloufar; Klein, Jeffrey; Koopman, Brian J.; Li, Dale; McMahon, Jeffrey; Mumby, Grace; Nati, Federico; Wollack, Edward J.

    2016-01-01

    The next generation Advanced ACTPol (AdvACT) experiment is currently underway and will consist of four Transition Edge Sensor (TES) bolometer arrays, with three operating together, totaling 5800 detectors on the sky. Building on experience gained with the ACTPol detector arrays, AdvACT will utilize various new technologies, including 150 mm detector wafers equipped with multichroic pixels, allowing for a more densely packed focal plane. Each set of detectors includes a feedhorn array of stacked silicon wafers which form a spline pro le leading to each pixel. This is then followed by a waveguide interface plate, detector wafer, back short cavity plate, and backshort cap. Each array is housed in a custom designed structure manufactured from high purity copper and then gold plated. In addition to the detector array assembly, the array package also encloses cryogenic readout electronics. We present the full mechanical design of the AdvACT high frequency (HF) detector array package along with a detailed look at the detector array stack assemblies. This experiment will also make use of extensive hardware and software previously developed for ACT, which will be modi ed to incorporate the new AdvACT instruments. Therefore, we discuss the integration of all AdvACT arrays with pre-existing ACTPol infrastructure.

  20. Performance experiments with alternative advanced teleoperator control modes for a simulated solar maximum satellite repair

    NASA Technical Reports Server (NTRS)

    Das, H.; Zak, H.; Kim, W. S.; Bejczy, A. K.; Schenker, P. S.

    1992-01-01

    Experiments are described which were conducted at the JPL Advanced Teleoperator Lab to demonstrate and evaluate the effectiveness of various teleoperator control modes in the performance of a simulated Solar Max Satellite Repair (SMSR) task. THe SMSR was selected as a test because it is very rich in performance capability requirements and it actually has been performed by two EVA astronauts in the Space Shuttle Bay in 1984. The main subtasks are: thermal blanket removal; installation of a hinge attachment for electrical panel opening; opening of electrical panel; removal of electrical connectors; relining of cable bundles; replacement of electrical panel; securing parts and cables; re-mate electrical connectors; closing of electrical panel; and reinstating thermal blanket. The current performance experiments are limited to thermal blanket cutting, electrical panel unbolting and handling electrical bundles and connectors. In one formal experiment even different control modes were applied to the unbolting and reinsertion of electrical panel screws subtasks. The seven control modes are alternative combinations of manual position and rate control with force feedback and remote compliance referenced to force-torque sensor information. Force-torque sensor and end effector position data and task completion times were recorded for analysis and quantification of operator performance.

  1. Next Generation Climate Change Experiments Needed to Advance Knowledge and for Assessment of CMIP6

    SciTech Connect

    Katzenberger, John; Arnott, James; Wright, Alyson

    2014-10-30

    The Aspen Global Change Institute hosted a technical science workshop entitled, “Next generation climate change experiments needed to advance knowledge and for assessment of CMIP6,” on August 4-9, 2013 in Aspen, CO. Jerry Meehl (NCAR), Richard Moss (PNNL), and Karl Taylor (LLNL) served as co-chairs for the workshop which included the participation of 32 scientists representing most of the major climate modeling centers for a total of 160 participant days. In August 2013, AGCI gathered a high level meeting of representatives from major climate modeling centers around the world to assess achievements and lessons learned from the most recent generation of coordinated modeling experiments known as the Coupled Model Intercomparison Project – 5 (CMIP5) as well as to scope out the science questions and coordination structure desired for the next anticipated phase of modeling experiments called CMIP6. The workshop allowed for reflection on the coordination of the CMIP5 process as well as intercomparison of model results, such as were assessed in the most recent IPCC 5th Assessment Report, Working Group 1. For example, this slide from Masahiro Watanabe examines performance on a range of models capturing Atlantic Meridional Overturning Circulation (AMOC).

  2. The Next Generation Nuclear Plant Graphite Creep Experiment Irradiation in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2010-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six gas reactor graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These graphite irradiations are being accomplished to support development of the next generation reactors in the United States. The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant (NGNP) Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six stacks will have differing compressive loads applied to the top half of each pair of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be the capability of sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during initial start-up of

  3. Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

    SciTech Connect

    Flury, Markus; Harsh, James B.; Zachara, John M.; Jin, Yan

    2002-06-01

    This project seeks to improve the basic understanding of colloid and colloid-facilitated transport of Cs in the vadose zone. The specific objectives are: (1) Determine the structure, composition, and surface charge characteristics of colloidal particles formed under conditions similar to those occurring during leakage of waste typical of Hanford tank supernatants into soils and sediments surrounding the tanks. (2) Characterize the mutual interactions between colloids, contaminant, and soil matrix in batch experiments under various ionic strength and pH conditions. We will investigate the nature of the solid-liquid interactions and the kinetics of the reactions. (3) Evaluate mobility of colloids through soil under different degrees of water saturation and solution chemistry (ionic strength and pH). (4) Determine the potential of colloids to act as carriers to transport the contaminant through the vadose zone and verify the results through comparison with field samples collected under leaking tanks. Results of this project will help to understand the fundamental mechanisms of Cs transport under the leaking Hanford tanks, and thus contribute to the long-term clean-up strategies at the Hanford site.

  4. Assembly of colloidal strings in a simple fluid flow

    NASA Astrophysics Data System (ADS)

    Abe, Yu; Francis, Lorraine; Cheng, Xiang

    Colloidal particles self-assemble into ordered structures ranging from face- and body-centered cubic crystals to binary ionic crystals and to kagome lattices. Such diverse micron-scale structures are of practical importance for creating photonic materials and also of fundamental interest for probing equilibrium and non-equilibrium statistical mechanics. As a particularly interesting example, 1D colloidal strings provide a unique system for investigating non-equilibrium dynamics of crystal lattices. Here, we report a simple experimental method for constructing 1D colloidal crystals, where colloidal particles self-assemble into flow-aligned string structures near solid boundary under unidirectional flows. Using fast confocal microscopy, we explore the degree of particle alignment as functions of flow rate, particle concentrations, wetting properties of solid boundary and ionic strength of solvent. Through our systematic experiments, we show that these colloidal strings arise from hydrodynamic coupling, facilitated by electrostatic attractions between particles and the boundary. Compared with previous methods, our work provides a much simpler experimental procedure for assembling a large number of colloidal strings.

  5. Using colloids to model atomic thin film growth

    NASA Astrophysics Data System (ADS)

    Ganapathy, Rajesh; Buckley, Mark; Cohen, Itai

    2009-03-01

    We epitaxially grow colloidal thin films by sedimenting micron sized colloidal particles on a microfabricated substrate. The attractive interaction between the colloids, induced by a depletant polymer, leads to the nucleation of islands that grow and coalesce with one another. We use confocal microscopy and particle tracking to study the dynamics of the colloidal particles as they diffuse, aggregate and rearrange configurations during deposition. The saturation island density is estimated as a function of the deposition rate and depletant concentration. We find that our results are in excellent agreement with those obtained from atomic deposition experiments suggesting that our system can be used to model various phenomena that occur in atomic thin film growth. Furthermore, we quantify the Ehrlich-Schwoebel step edge barrier by using holographic optical tweezers to create artificial islands and study the dynamics of colloidal monomers placed on the edge of these islands. Owing to the short-range of the attractive interaction in our system, the origin of the step edge barrier in colloids is strikingly different from atoms.

  6. Causes and implications of colloid and microorganism retention hysteresis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1...

  7. Natural Colloid Mobilization in Unsaturated Hanford Coarse Sand Under Transient Flow and Transient Chemical Conditions

    NASA Astrophysics Data System (ADS)

    Cheng, T.; Saiers, J. E.

    2007-12-01

    Colloid-sized clay, carbonate, and metal oxide particles are ubiquitous in the vadose zone and strongly adsorb dissolved contaminants such as metals and radionuclides. Under certain conditions, colloid particles are readily mobilized (released) into pore water and travel in a nearly conservative fashion and thus can facilitate the transport of contaminants. Although much progress has been made toward identifying and modeling colloid mobilization and transport processes in ideal, homogeneous systems, our understanding of the phenomenon in non-ideal, heterogeneous systems is still limited. We investigated natural colloid mobilization and transport in laboratory columns packed with Hanford Coarse Sand, a heterogeneous natural sediment. Our major focus was the role of transient flow and transient chemical conditions on colloid release and transport in unsaturated media. We found that a moving air-water interface had the greatest effects on the mobilization of colloid, and up to ~1000 mg/L of colloid was mobilized during column drainage at an ionic strength of 2 mM. An increase in flow rate or decrease in ionic strength also mobilized colloids. A model that accounts for transient pore water flow, colloid transport, and mass transfer in unsaturated media was developed to describe colloid mobilization in our column experiments. Both our experimental and modeling results showed the important role of moving air-water interfaces, changes in moisture content, and changes in ionic strength in mobilizing natural colloids in heterogeneous natural sediments. This work has contributed to our knowledge of colloid and colloid-associated contaminant mobilization in real vadose-zone environments under transient flow and transient chemical conditions.

  8. Colloid-Facilitated Radionuclide Transport at the Potential Yucca Mountain Repository

    NASA Astrophysics Data System (ADS)

    Alcorn, S. R.; Mertz, C. J.

    2001-12-01

    In a geologic repository for nuclear waste, transport of radionuclides on or within colloids may be important for radionuclides of concern that have low solubility and can be entrained in, or sorbed onto, colloidal particles generated within the repository system. It is anticipated that colloids will be formed and mobilized at the potential Yucca Mountain repository as a result of alteration of high-level radioactive waste (HLW) and spent nuclear fuel (SNF) waste forms, as well as corrosion of engineered barrier system (EBS) components. The abundance of colloids leaving a breached waste package and entering the repository drift will depend on the extent of waste form and EBS component alteration and the alteration products formed. Further, colloid abundance and stability will depend on such environmental factors as the ionic strength, pH, cation concentrations, natural colloid content, and organic acid and microbe content of groundwater entering the waste package from the drift. Colloids may flocculate and settle, be chemically retarded, mechanically filtered, or dissolve. In addition, colloids may sorb readily at the interfaces between air and water in rocks and engineered barriers and, depending upon the characteristics and degree of saturation of the porous medium, may be immobilized, retarded, or transported. A methodology for modeling colloid-facilitated radionuclide transport in the potential repository at Yucca Mountain was developed for use in Total System Performance Assessment calculations. The model incorporates several colloid sources and addresses factors affecting colloid stability and concentration as well as distribution and attachment of radionuclides onto colloids. Waste form corrosion tests performed at Argonne National Laboratory (ANL) have focused on determination of colloid composition, stability, concentration, size distribution, and associated radionuclide concentration. Data from these experiments were used as model inputs.

  9. Treatment of advanced thyroid cancer with targeted therapies: ten years of experience.

    PubMed

    Viola, David; Valerio, Laura; Molinaro, Eleonora; Agate, Laura; Bottici, Valeria; Biagini, Agnese; Lorusso, Loredana; Cappagli, Virginia; Pieruzzi, Letizia; Giani, Carlotta; Sabini, Elena; Passannati, Paolo; Puleo, Luciana; Matrone, Antonio; Pontillo-Contillo, Benedetta; Battaglia, Valentina; Mazzeo, Salvatore; Vitti, Paolo; Elisei, Rossella

    2016-04-01

    Thyroid cancer is rare, but it is the most frequent endocrine malignancy. Its prognosis is generally favorable, especially in cases of well-differentiated thyroid cancers (DTCs), such as papillary and follicular cancers, which have survival rates of approximately 95% at 40 years. However, 15-20% of cases became radioiodine refractory (RAI-R), and until now, no other treatments have been effective. The same problems are found in cases of poorly differentiated (PDTC) and anaplastic (ATC) thyroid cancers and in at least 30% of medullary thyroid cancer (MTC) cases, which are very aggressive and not sensitive to radioiodine. Tyrosine kinase inhibitors (TKIs) represent a new approach to the treatment of advanced cases of RAI-R DTC, MTC, PDTC, and, possibly, ATC. In the past 10 years, several TKIs have been tested for the treatment of advanced, progressive, and RAI-R thyroid tumors, and some of them have been recently approved for use in clinical practice: sorafenib and lenvatinib for DTC and PDTC and vandetanib and cabozantinib for MTC. The objective of this review is to present the current status of the treatment of advanced thyroid cancer with the use of innovative targeted therapies by describing both the benefits and the limits of their use based on the experiences reported so far. A comprehensive analysis and description of the molecular basis of these therapies, as well as new therapeutic perspectives, are reported. Some practical suggestions are given for both the choice of patients to be treated and their management, with particular regard to the potential side effects. PMID:27207700

  10. Circulating fluidized bed tehnology in biomass combustion-performance, advances and experiences

    SciTech Connect

    Mutanen, K.I.

    1995-11-01

    Development of fluidized bed combustion (FBC) was started both in North America and in Europe in the 1960`s. In Europe and especially in Scandinavia the major driving force behind the development was the need to find new more efficient technologies for utilization of low-grade fuels like different biomasses and wastes. Both bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) technologies were under intensive R&D,D efforts and have now advanced to dominating role in industrial and district heating power plant markets in Europe. New advanced CFB designs are now entering the markets. In North America and especially in the US the driving force behind the FBC development was initially the need to utilize different types of coals in a more efficient and environmentally acceptable way. The present and future markets seem to be mainly in biomass and multifuel applications where there is benefit from high combustion efficiency, high fuel flexibility and low emissions such as in the pulp and paper industry. The choice between CFB technology and BFB technology is based on selected fuels, emission requirements, plant size and on technical and economic feasibility. Based on Scandinavian experience there is vast potential in the North American industry to retrofit existing oil fired, pulverized coal fired, chemical recovery or grate fired boilers with FBC systems or to build a new FBC based boiler plant. This paper will present the status of CFB technologies and will compare technical and economic feasibility of CFB technology to CFB technology to BFB and also to other combustion methods. Power plant projects that are using advanced CFB technology e.g. Ahlstrom Pyroflow Compact technology for biomass firing and co-firing of biomass with other fuels will also be introduced.

  11. Developing clinical competency: Experiences and perceptions of Advanced Midwifery Practitioners in training.

    PubMed

    Gaskell, Lynne; Beaton, Susan

    2015-07-01

    This paper will describe the experiences and perception of a cohort of trainee Advanced Midwifery Practitioners (AMP's) during their training on an MSc in Advanced Practice. The educational philosophy underpinning the master's programme is interprofessional learning linked closely to work based learning and assessment. The focus group explored how the AMP's were developing core competencies within four domains: The links between the university and clinical assessments were instrumental in developing both midwifery and specialised skills required for extending their scope of practice. The changing demographics of their client group facilitated the need to provide safe assessment and management of ladies with complex health and social needs in pregnancy and childbirth; provide specialised clinics and the development of a robust staff training and assessment process. The generic competencies they gained improved collaborative working with their medical colleagues, raising the trainees profile and acceptance of their extended role. In addition to this, development of specialised midwifery skills promoted a high degree of decision making responsibilities within midwifery to facilitate service development and promote evidence based care. PMID:25892367

  12. Intraoperative radiation therapy for advanced cervical metastasis: a single institution experience

    PubMed Central

    2011-01-01

    Background The purpose of this study is to review our experience with the use of IORT for patients with advanced cervical metastasis. Methods Between August 1982 and July 2007, 231 patients underwent neck dissections as part of initial therapy or as salvage treatment for advanced cervical node metastases resulting from head and neck malignancies. IORT was administered as a single fraction to a dose of 15 Gy or 20 Gy in most pts. The majority was treated with 5 MeV electrons (112 pts, 50.5%). Results 1, 3, and 5 years overall survival (OS) after surgery + IORT was 58%, 34%, and 26%, respectively. Recurrence-free survival (RFS) at 1, 3, and 5 years was 66%, 55%, and 49%, respectively. Disease recurrence was documented in 83 (42.8%) pts. The majority of recurrences were regional (38 pts), as compared to local recurrence in 20 pts and distant failures in 25 pts. There were no perioperative fatalities. Conclusions IORT results in effective local disease control at acceptable levels of toxicity. Our results support the initiation of a phase III trial comparing outcomes for patients with cervical metastasis treated with or without IORT. PMID:21676211

  13. New generation of cryogen free advanced superconducting magnets for neutron scattering experiments

    NASA Astrophysics Data System (ADS)

    Kirichek, O.; Brown, J.; Adroja, D. T.; Manuel, P.; Kouzmenko, G.; Bewley, R. I.; Wotherspoon, R.

    2012-12-01

    Recent advances in superconducting technology and cryocooler refrigeration have resulted in a new generation of advanced superconducting magnets for neutron beam applications. These magnets have outstanding parameters such as high homogeneity and stability at highest magnetic fields possible, a reasonably small stray field, low neutron scattering background and larger exposure to neutron detectors. At the same time the pulse tube refrigeration technology provides a complete re-condensing regime which allows to minimise the requirements for cryogens without introducing additional noise and mechanical vibrations. The magnets can be used with dilution refrigerator insert which expands the temperature range from 20mK to 300K. Here we are going to present design, test results and the operational data of the 14T magnet for neutron diffraction and the 9T wide angle chopper magnet for neutron spectroscopy developed by Oxford Instruments in collaboration with ISIS neutron source. First scientific results obtained from the neutron scattering experiments with these magnets are also going to be discussed.

  14. Neural network setpoint control of an advanced test reactor experiment loop simulation

    SciTech Connect

    Cordes, G.A.; Bryan, S.R.; Powell, R.H.; Chick, D.R.

    1990-09-01

    This report describes the design, implementation, and application of artificial neural networks to achieve temperature and flow rate control for a simulation of a typical experiment loop in the Advanced Test Reactor (ATR) located at the Idaho National Engineering Laboratory (INEL). The goal of the project was to research multivariate, nonlinear control using neural networks. A loop simulation code was adapted for the project and used to create a training set and test the neural network controller for comparison with the existing loop controllers. The results for three neural network designs are documented and compared with existing loop controller action. The neural network was shown to be as accurate at loop control as the classical controllers in the operating region represented by the training set. 9 refs., 28 figs., 2 tabs.

  15. Advancements in RNASeqGUI towards a Reproducible Analysis of RNA-Seq Experiments.

    PubMed

    Russo, Francesco; Righelli, Dario; Angelini, Claudia

    2016-01-01

    We present the advancements and novelties recently introduced in RNASeqGUI, a graphical user interface that helps biologists to handle and analyse large data collected in RNA-Seq experiments. This work focuses on the concept of reproducible research and shows how it has been incorporated in RNASeqGUI to provide reproducible (computational) results. The novel version of RNASeqGUI combines graphical interfaces with tools for reproducible research, such as literate statistical programming, human readable report, parallel executions, caching, and interactive and web-explorable tables of results. These features allow the user to analyse big datasets in a fast, efficient, and reproducible way. Moreover, this paper represents a proof of concept, showing a simple way to develop computational tools for Life Science in the spirit of reproducible research. PMID:26977414

  16. Tracking Patient Encounters and Clinical Skills to Determine Competency in Ambulatory Care Advanced Pharmacy Practice Experiences

    PubMed Central

    Pereira, Chrystian R.; Harris, Ila M.; Moon, Jean Y.; Westberg, Sarah M.; Kolar, Claire

    2016-01-01

    Objective. To determine if the amount of exposure to patient encounters and clinical skills correlates to student clinical competency on ambulatory care advanced pharmacy practice experiences (APPEs). Design. Students in ambulatory care APPEs tracked the number of patients encountered by medical condition and the number of patient care skills performed. At the end of the APPE, preceptors evaluated students’ competency for each medical condition and skill, referencing the Dreyfus model for skill acquisition. Assessment. Data was collected from September 2012 through August 2014. Forty-six responses from a student tracking tool were matched to preceptor ratings. Students rated as competent saw more patients and performed more skills overall. Preceptors noted minimal impact on workload. Conclusions. Increased exposure to patient encounters and skills performed had a positive association with higher Dreyfus stage, which may represent a starting point in the conversation for more thoughtful design of ambulatory care APPEs. PMID:26941440

  17. The CNO Concentration in Cosmic Ray Spectrum as Measured From The Advanced Thin Ionization Calorimeter Experiment

    NASA Technical Reports Server (NTRS)

    Fazely, A. R.; Gunasingha, R. M.; Adams, James H., Jr.; Ahn, H.; Ampe, J.; Bashindzhagyan, G.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present preliminary results on the spectra of CNO nuclei in the cosmic radiation as measured in the first flight of the Advanced Thin Ionization Calorimeter Balloon Experiment (ATIC) which lasted for 16 days, starting in December, 2000 with a launch from McMurdo, Antarctica. ATIC is a multiple, long duration balloon flight, investigation for the study of cosmic ray spectra from below 50 GeV to near 100 TeV total energy, using a fully active Bismuth Germanate (BGO) calorimeter. It is equipped with the first large area mosaic of small fully depleted silicon detector pads capable of charge identification in cosmic rays from H to Fe. As a redundancy check for the charge identification and a coarse particle tracking system, three projective layers of x-y scintillator hodoscopes were employed, above, in the center and below a Carbon interaction "target".

  18. Advanced photoelectric effect experiment beamline at Elettra: A surface science laboratory coupled with Synchrotron Radiation

    SciTech Connect

    Panaccione, G.; Vobornik, I.; Fujii, J.; Krizmancic, D.; Annese, E.; Giovanelli, L.; Maccherozzi, F.; Salvador, F.; De Luisa, A.; Benedetti, D.; Gruden, A.; Bertoch, P.; Rossi, G.; Polack, F.; Cocco, D.; Sostero, G.; Diviacco, B.; Hochstrasser, M.; Maier, U.; Pescia, D.; and others

    2009-04-15

    We report the main characteristics of the advanced photoelectric effect experiments beamline, operational at Elettra storage ring, featuring a fully independent double branch scheme obtained by the use of chicane undulators and able to keep polarization control in both linear and circular mode. The paper describes the novel technical solutions adopted, namely, (a) the design of a quasiperiodic undulator resulting in optimized suppression of higher harmonics over a large photon energy range (10-100 eV), (b) the thermal stability of optics under high heat load via cryocoolers, and (c) the end station interconnected setup allowing full access to off-beam and on-beam facilities and, at the same time, the integration of users' specialized sample growth chambers or modules.

  19. Impact of Instruction and Feedback on Reflective Responses during an Ambulatory Care Advanced Pharmacy Practice Experience.

    PubMed

    Teply, Robyn; Spangler, Mikayla; Klug, Laura; Tilleman, Jennifer; Coover, Kelli

    2016-06-25

    Objective. To investigate whether instruction and feedback on reflective responses are beneficial in developing pharmacy students to become more reflective practitioners. Methods. Students on an advanced pharmacy practice experience answered weekly reflection questions and were randomly assigned to either an intervention (received instruction and feedback on reflection) or control group. The final week's responses were de-identified and two blinded faculty members independently categorized them as reflective or nonreflective. The primary outcome measure was comparing the number of "reflective" responses in each group. Results. The responses were classified as reflective in 83.3% of students in the intervention group (n=18) compared to 37.5% of the control group (n=16). The odds that the response was categorized as reflective were 8.3 times higher in the intervention group. Conclusion. Providing instruction and feedback to students improved the likelihood that their work was reflective. PMID:27402984

  20. Advanced Cosmic-ray Composition Experiment for Space Station: ISS accommodation study

    SciTech Connect

    Wefel, John P.

    1999-01-22

    ACCESS--Advanced Cosmic-ray Composition Experiment for Space Station--was selected as a new Mission Concept under NRA 96-OSS-03, with the goal of combining calorimeter and transition radiation techniques to provide measurements of cosmic rays from Hydrogen through Nickel up to energies approaching the 'knee' in the cosmic ray all particle spectrum, plus providing measurements of the Z>28 (Ultra-Heavy) nuclei at all energies. An instrument to perform such an investigation is undergoing an ISS/STS Accommodation Study at JSC. The instrument concept, the mission plan, and the accommodation issues for an ISS attached payload which include, in part, the carrier, ISS Site, thermal control, power, data and operations are described and the current status of these issues, for an ACCESS Mission, is summarized.

  1. Advancements in RNASeqGUI towards a Reproducible Analysis of RNA-Seq Experiments

    PubMed Central

    Russo, Francesco; Righelli, Dario

    2016-01-01

    We present the advancements and novelties recently introduced in RNASeqGUI, a graphical user interface that helps biologists to handle and analyse large data collected in RNA-Seq experiments. This work focuses on the concept of reproducible research and shows how it has been incorporated in RNASeqGUI to provide reproducible (computational) results. The novel version of RNASeqGUI combines graphical interfaces with tools for reproducible research, such as literate statistical programming, human readable report, parallel executions, caching, and interactive and web-explorable tables of results. These features allow the user to analyse big datasets in a fast, efficient, and reproducible way. Moreover, this paper represents a proof of concept, showing a simple way to develop computational tools for Life Science in the spirit of reproducible research. PMID:26977414

  2. Impact of Instruction and Feedback on Reflective Responses during an Ambulatory Care Advanced Pharmacy Practice Experience

    PubMed Central

    Spangler, Mikayla; Klug, Laura; Tilleman, Jennifer; Coover, Kelli

    2016-01-01

    Objective. To investigate whether instruction and feedback on reflective responses are beneficial in developing pharmacy students to become more reflective practitioners. Methods. Students on an advanced pharmacy practice experience answered weekly reflection questions and were randomly assigned to either an intervention (received instruction and feedback on reflection) or control group. The final week’s responses were de-identified and two blinded faculty members independently categorized them as reflective or nonreflective. The primary outcome measure was comparing the number of “reflective” responses in each group. Results. The responses were classified as reflective in 83.3% of students in the intervention group (n=18) compared to 37.5% of the control group (n=16). The odds that the response was categorized as reflective were 8.3 times higher in the intervention group. Conclusion. Providing instruction and feedback to students improved the likelihood that their work was reflective. PMID:27402984

  3. Colloidal aggregation in polymer blends.

    PubMed

    Benhamou, M; Ridouane, H; Hachem, E-K; Derouiche, A; Rahmoune, M

    2005-06-22

    We consider here a low-density assembly of colloidal particles immersed in a critical polymer mixture of two chemically incompatible polymers. We assume that, close to the critical point of the free mixture, the colloids prefer to be surrounded by one polymer (critical adsorption). As result, one is assisted to a reversible colloidal aggregation in the nonpreferred phase, due the existence of a long-range attractive Casimir force between particles. This aggregation is a phase transition driving the colloidal system from dilute to dense phases, as the usual gas-liquid transition. We are interested in a quantitative investigation of the phase diagram of the immersed colloids. We suppose that the positions of particles are disordered, and the disorder is quenched and follows a Gaussian distribution. To apprehend the problem, use is made of the standard phi(4) theory, where the field phi represents the composition fluctuation (order parameter), combined with the standard cumulant method. First, we derive the expression of the effective free energy of colloids and show that this is of Flory-Huggins type. Second, we find that the interaction parameter u between colloids is simply a linear combination of the isotherm compressibility and specific heat of the free mixture. Third, with the help of the derived effective free energy, we determine the complete shape of the phase diagram (binodal and spinodal) in the (Psi,u) plane, with Psi as the volume fraction of immersed colloids. The continuous "gas-liquid" transition occurs at some critical point K of coordinates (Psi(c) = 0.5,u(c) = 2). Finally, we emphasize that the present work is a natural extension of that, relative to simple liquid mixtures incorporating colloids. PMID:16035822

  4. Colloids in Acute Burn Resuscitation.

    PubMed

    Cartotto, Robert; Greenhalgh, David

    2016-10-01

    Colloids have been used in varying capacities throughout the history of formula-based burn resuscitation. There is sound experimental evidence that demonstrates colloids' ability to improve intravascular colloid osmotic pressure, expand intravascular volume, reduce resuscitation requirements, and limit edema in unburned tissue following a major burn. Fresh frozen plasma appears to be a useful and effective immediate burn resuscitation fluid but its benefits must be weighed against its costs, and risks of viral transmission and acute lung injury. Albumin, in contrast, is less expensive and safer and has demonstrated ability to reduce resuscitation requirements and possibly limit edema-related morbidity. PMID:27600123

  5. Two-dimensional dipolar nematic colloidal crystals.

    PubMed

    Skarabot, M; Ravnik, M; Zumer, S; Tkalec, U; Poberaj, I; Babic, D; Osterman, N; Musevic, I

    2007-11-01

    We study the interactions and directed assembly of dipolar nematic colloidal particles in planar nematic cells using laser tweezers. The binding energies for two stable configurations of a colloidal pair with homeotropic surface alignment are determined. It is shown that the orientation of the dipolar colloidal particle can efficiently be controlled and changed by locally quenching the nematic liquid crystal from the laser-induced isotropic phase. The interaction of a single colloidal particle with a single colloidal chain is determined and the interactions between pairs of colloidal chains are studied. We demonstrate that dipolar colloidal chains self-assemble into the two-dimensional (2D) dipolar nematic colloidal crystals. An odd-even effect is observed with increasing number of colloidal chains forming the 2D colloidal crystal. PMID:18233658

  6. Dynamics of Polymers in Colloidal Flows

    NASA Astrophysics Data System (ADS)

    Chen, Hsieh; Alexander-Katz, Alfredo

    2011-03-01

    This research is motivated by recent studies on the von Willebrand factor (vWF), a large multimeric protein that plays an essential role in the initial stages of blood clotting in blood vessels. Recent experiments substantiated the hypothesis that the vWF is activated by shear stress in blood flow that causes its shape to transform from a compact globule to an extended state, and biological function is obtained only in the extended state. Simple simulations (which only consider a single polymer in bulk shear flow) have successfully reproduced the observed dynamics of the vWF. However, a more refined model is still demanding for the better understanding of the behaviors of this biomolecule in the physiological environments. Here we refine the existing model by adding the drifting colloids into the flows to mimic the presence of the blood cells in the bloodstream. Preliminary result shows that colloids greatly influence the dynamics of the polymers. It is observed that the average extensions of polymers along and perpendicular to the shear flow direction are both increased with the presence of the colloids.

  7. Synthesis of metal colloids in inverse microemulsions

    NASA Astrophysics Data System (ADS)

    Barnickel, P.; Wokaun, A.

    Colloidal silver and gold particles have been prepared by reduction of aqueous metal salt solutions in inverse microemulsions. The sols are characterized by absorption spectroscopy and electron microscopy. Ultrasound treatment during reduction results in a narrower size distribution of the colloidal particles, as evidenced by a narrower absorption band. Photochemical silver and gold sol formation, without the addition of a reducing agent, has been observed for inverse microemulsions of metal salt solutions in a medium consisting of dodecyl-heptaethyleneglycol-ether and hexane. The particle sizes determined from electron microscopy have been used as input parameters for the simulation of absorption spectra, based on the electromagnetic theory of localized surface plasmon excitation. For the gold sols a quantitative agreement between experimental and simulated spectra is obtained. With the silver colloids, the observed red-shift of the absorption maximum points to the presence of an ionic layer on the surface of the particles. When this layer is included in the theoretical model, good agreement with the experiment is achieved.

  8. Colloidal particle deposition in turbulent flow

    SciTech Connect

    Morton, D.S.

    1994-05-01

    A theoretical analysis is presented which describes the initial deposition of monodispersed spherical colloidal particles from a steady fully developed turbulent flow onto conduit walls. When the net particle-conduit electrical interaction potential is attractive, particle deposition is shown to be often governed by turbulent hydrodynamics. When the net particle-conduit electrical interaction potential possess a repulsive maximum, particle deposition to first order is uniform and depends solely on electrical interaction effects. The developed theoretical model specialized to orifice deposition with the use of Harwell Flow3D turbulence modelling software qualitatively described the deposition of 0.5 {mu}m silica particles onto glass orifices from an aqueous suspension. The effect of the electrical double layer on the rate of colloidal particle deposition in laminar flow has been described by Spielman and Friedlander (1), Dahneke (2), Bowen et al. (3) and Bowen and Epstein (4). This article describes the extension of their work to colloidal particle deposition under steady fully developed turbulent flow conditions. This article also reports the results of orifice particle deposition experiments which were conducted to qualitatively investigate the developed theoretical model.

  9. Colloidal particle deposition in turbulent flow

    NASA Astrophysics Data System (ADS)

    Morton, D. S.

    1994-05-01

    A theoretical analysis is presented which describes the initial deposition of monodispersed spherical colloidal particles from a steady fully developed turbulent flow onto conduit walls. When the net particle-conduit electrical interaction potential is attractive, particle deposition is shown to be often governed by turbulent hydrodynamics. When the net particle-conduit electrical interaction potential possess a repulsive maximum, particle deposition to first order is uniform and depends solely on electrical interaction effects. The developed theoretical model specialized to orifice deposition with the use of Harwell Flow 3D turbulence modelling software qualitatively described the deposition of 0.5 (mu)m silica particles onto glass orifices from an aqueous suspension. The effect of the electrical double layer on the rate of colloidal particle deposition in laminar flow has been described by Spielman and Friedlander, Dahneke, Bowen et al. and Bowen and Epstein. This article describes the extension of their work to colloidal particle deposition under steady fully developed turbulent flow conditions. This article also reports the results of orifice particle deposition experiments which were conducted to qualitatively investigate the developed theoretical model.

  10. Fission Product Monitoring and Release Data for the Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John B. Walter; Jason M. Harp; Mark W. Drigert; Edward L. Reber

    2010-10-01

    The AGR-1 experiment is a fueled multiple-capsule irradiation experiment that was irradiated in the Advanced Test Reactor (ATR) from December 26, 2006 until November 6, 2009 in support of the Very High Temperature Reactor (VHTR) Technology Development Office (TDO) Fuel Development and Qualification program. An important measure of the fuel performance is the quantification of the fission product releases over the duration of the experiment. To provide this data for the inert fission gasses(Kr and Xe), a fission product monitoring system (FPMS) was developed and implemented to monitor the individual capsule effluents for the radioactive species. The FPMS continuously measured the concentrations of various krypton and xenon isotopes in the sweep gas from each AGR-1 capsule to provide an indicator of fuel irradiation performance. Spectrometer systems quantified the concentrations of Kr-85m, Kr-87, Kr-88, Kr-89, Kr-90, Xe-131m, Xe-133, Xe 135, Xe 135m, Xe-137, Xe-138, and Xe-139 accumulated over repeated eight hour counting intervals.-. To determine initial fuel quality and fuel performance, release activity for each isotope of interest was derived from FPMS measurements and paired with a calculation of the corresponding isotopic production or birthrate. The release activities and birthrates were combined to determine Release-to-Birth ratios for the selected nuclides. R/B values provide indicators of initial fuel quality and fuel performance during irradiation. This paper presents a brief summary of the FPMS, the release to birth ratio data for the AGR-1 experiment and preliminary comparisons of AGR-1 experimental fuels data to fission gas release models.

  11. Colloid-facilitated Cs transport through water-saturated Hanford sediment and Ottawa sand.

    PubMed

    Zhuang, Jie; Flury, Markus; Jin, Yan

    2003-11-01

    In this study, a series of saturated column experiments were conducted to investigate effects of colloids on Cs transport in two types of porous media (Hanford sediment characteristic of 2:1 clay minerals and silica Ottawa sand). The colloids used were obtained by reacting Hanford sediment with simulated tank waste solutions. Because of the highly nonlinear nature of Cs sorption found in batch experiments, we used two different concentrations of Cs (7.5 x 10(-5) M and 1.4 x 10(-8) M) for the transport experiments. The presence of colloids facilitated the transport of Cs through both Hanford sediment and Ottawa sand via association of Cs with mobile colloidal particles. Due to the nonlinearity of the Cs sorption, the colloid-facilitated Cs transportwas more pronounced atthe low Cs concentration (1.4 x 10(-8) M) than at the high concentration (7.5 x 10(-5) M) when expressed relative to the inflow Cs concentration. In the absence of colloids, no Cs moved through the 10-cm long columns during the experiment within about 20 pore volumes, exceptfor the high Cs concentration in the Ottawa sand where a complete Cs breakthrough was obtained. Also, it was found that colloid-associated Cs could be partially stripped off from colloids during the transport. The stripping effect was controlled by both Cs concentration and sorption capacity of the transport matrix. PMID:14620817

  12. Colloid labelled with radionuclide and method

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1990-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  13. Method of making colloid labeled with radionuclide

    DOEpatents

    Atcher, Robert W.; Hines, John J.

    1991-01-01

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

  14. Colloid labelled with radionuclide and method

    DOEpatents

    Atcher, R.W.; Hines, J.J.

    1990-11-13

    A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints. No Drawings

  15. Canadian Advanced Nanospace Experiment 2 Orbit Operations: Two Years of Pushing the Nanosatellite Performance Envelope

    NASA Astrophysics Data System (ADS)

    Sarda, Karan

    The objective of the Canadian Advanced Nanospace eXperiment (CanX) program is to de-velop highly capable nanospacecraft, i.e. spacecraft under 10 kilograms, in short timeframes of 2-3 years. CanX missions offer low-cost and rapid access to space for scientists, technol-ogy developers and operationally-responsive missions. The Space Flight Laboratory (SFL), at the University of Toronto Institute for Aerospace Studies (UTIAS) has developed the CanX-2 nanosatellite that launched in April 2008. CanX-2, a 3.5-kg, 10 x 10 x 34 cm satellite, features a collection of scientific and engineering payloads that push the envelope of capability for this class of spacecraft. The primary mission of CanX-2 is to perform a number of university exper-iments. These experiments include a miniature atmospheric spectrometer designed to detect greenhouse gas concentrations, a GPS signal occultation experiment designed to map electron and water vapour concentrations in the ionosphere and troposphere respectively, and a materi-als science experiment which evaluates a novel atomic oxygen resistant coating. The secondary mission of CanX-2 is to test and demonstrate several enabling technologies for precise formation flight. These technologies include a custom cold-gas propulsion system, a nanosatellite reac-tion wheel as part of a three-axis stabilized attitude control subsystem, and a GPS receiver. After two successful years in orbit, the nanosatellite has met or exceeded all mission objectives and continues to demonstrate the cost-effective capabilities of this class of spacecraft. Key achievements to date include a characterization of the propulsion system, a full demonstration of the attitude determination and control subsystem including capabilities in accurate pay-load pointing, unprecedented radio performance for an operational nanosatellite, and hundreds of successful science operations. The mission, the engineering and scientific payloads, and a discussion of notable orbit

  16. Preparation of colloidal graphene in quantity by electrochemical exfoliation.

    PubMed

    Chen, Kunfeng; Xue, Dongfeng

    2014-12-15

    We reported the preparation of colloidal graphene in quantity via the anodic exfoliation of graphite in (NH4)2SO4 aqueous solution. In the currently designed electrochemical exfoliation route, mass high-quality graphene was produced within short reaction time, around 1h. The proposed electrochemical exfoliation mechanism showed that SO4(2-) and H2O can be intercalated into those graphite sheets, monolayer and few-layer graphene were obtained by the formation of gaseous SO2 and O2 within graphite sheets. Stability evaluation showed that our exfoliated colloidal graphene can be perfectly stabilized in DMF solvent more than 1 week. The colloidal graphene can be used to construct various simple and complex patterns by writing it on A4 paper, which can be applied to flexible printed electronic devices. Furthermore, colloidal graphene can show promising applications in the fabrication of binder- and additive-free electrodes for supercapacitors and lithium-ion batteries. Our present method shows huge potential for industrial-scale synthesis of high-quality graphene and further commercialization of graphene colloid for numerous advanced applications in flexible printed electronics and energy storage devices. PMID:25265584

  17. Use of Protecting Groups in Carbohydrate Chemistry: An Advanced Organic Synthesis Experiment

    NASA Astrophysics Data System (ADS)

    Cunha, Anna C.; Pereira, Leticia O. R.; de Souza, Maria Cecília B. V.; Ferreira, Vitor F.

    1999-01-01

    A simple and inexpensive three-step reaction sequence for advanced experimental organic chemistry using D-glucosamine hydrochloride as starting material for the synthesis of 2-amino-2-deoxy-1,3,4,6-tetra-O-acetyl-b-D-glucopyranose hydrochloride is described. D-Glucosamine hydrochloride is a carbohydrate derivative isolated from crab shells. It is inexpensive and readily available from most chemical companies. This reaction sequence is appropriate for teaching undergraduate students the correct use of protecting groups. This is a major concept in organic synthesis and one of the determinant factors in the successful realization of multiple-step synthetic projects. The aim of the experiment is to protect the hydroxyl groups of D-glucosamine leaving its amino group as hydrochloride salt. The experiment deals only with protection and deprotection reactions. All products are crystalline substances. The amino group of d-glucosamine hydrochloride is protected by a condensation reaction with p-methoxybenzaldehyde to produce the Schiff's base as a mixture of a- and b-anomers. The second step involves the protection of all hydroxyl groups by esterification reaction using acetic anhydride, forming the imino-tetraacetate derivative as the b-anomer. The stereospecificity of this reaction at the anomeric center is due to the voluminous imino group at C-2. Removal of the amino protection group of this derivative is the final step, which can be accomplished by a selective acid hydrolysis affording the desired peracylated D-glucosamine hydrochloride.

  18. The link evaluation terminal for the advanced communications technology satellite experiments program

    NASA Technical Reports Server (NTRS)

    May, Brian D.

    1992-01-01

    The experimental NASA satellite, Advanced Communications Technology Satellite (ACTS), introduces new technology for high throughput 30 to 20 GHz satellite services. Contained in a single communication payload is both a regenerative TDMA system and multiple 800 MHz 'bent pipe' channels routed to spot beams by a switch matrix. While only one mode of operation is typical during any experiment, both modes can operate simultaneously with reduced capability due to sharing of the transponder. NASA-Lewis instituted a ground terminal development program in anticipation of the satellite launch to verify the performance of the switch matrix mode of operations. Specific functions are built into the ground terminal to evaluate rain fade compensation with uplink power control and to monitor satellite transponder performance with bit error rate measurements. These functions were the genesis of the ground terminal's name, Link Evaluation Terminal, often referred to as LET. Connectors are included in LET that allow independent experimenters to run unique modulation or network experiments through ACTS using only the RF transmit and receive portions of LET. Test data indicate that LET will be able to verify important parts of ACTS technology and provide independent experimenters with a useful ground terminal. Lab measurements of major subsystems integrated into LET are presented. Bit error rate is measured with LET in an internal loopback mode.

  19. Current Practices in Global/International Advanced Pharmacy Practice Experiences: Preceptor and Student Considerations

    PubMed Central

    Ratka, Anna; Gleason, Shaun E.; Ombengi, David N.; Tofade, Toyin; Wigle, Patricia R.; Zapantis, Antonia; Ryan, Melody; Connor, Sharon; Jonkman, Lauren J.; Ochs, Leslie; Jungnickel, Paul W.; Abrons, Jeanine P.; Alsharif, Naser Z.

    2016-01-01

    The objective of this article is to describe the key areas of consideration for global/international advanced pharmacy practice experience (G/I APPE) preceptors, students and learning objectives. At the 2013 Annual Meeting of the American Association of Colleges of Pharmacy (AACP), the GPE SIG prepared and presented an initial report on the G/IAPPE initiatives. Round table discussions were conducted at the 2014 AACP Annual Meeting to document GPE SIG member input on key areas in the report. Literature search of PubMed, Google Scholar and EMBASE with keywords was conducted to expand this report. In this paper, considerations related to preceptors and students and learning outcomes are described. Preceptors for G/I APPEs may vary based on the learning outcomes of the experience. Student learning outcomes for G/I APPEs may vary based on the type of experiential site. Recommendations and future directions for development of G/IAPPEs are presented. Development of a successful G/I APPE requires significant planning and consideration of appropriate qualifications for preceptors and students. PMID:27170810

  20. Current Practices in Global/International Advanced Pharmacy Practice Experiences: Preceptor and Student Considerations.

    PubMed

    Dornblaser, Emily K; Ratka, Anna; Gleason, Shaun E; Ombengi, David N; Tofade, Toyin; Wigle, Patricia R; Zapantis, Antonia; Ryan, Melody; Connor, Sharon; Jonkman, Lauren J; Ochs, Leslie; Jungnickel, Paul W; Abrons, Jeanine P; Alsharif, Naser Z

    2016-04-25

    The objective of this article is to describe the key areas of consideration for global/international advanced pharmacy practice experience (G/I APPE) preceptors, students and learning objectives. At the 2013 Annual Meeting of the American Association of Colleges of Pharmacy (AACP), the GPE SIG prepared and presented an initial report on the G/IAPPE initiatives. Round table discussions were conducted at the 2014 AACP Annual Meeting to document GPE SIG member input on key areas in the report. Literature search of PubMed, Google Scholar and EMBASE with keywords was conducted to expand this report. In this paper, considerations related to preceptors and students and learning outcomes are described. Preceptors for G/I APPEs may vary based on the learning outcomes of the experience. Student learning outcomes for G/I APPEs may vary based on the type of experiential site. Recommendations and future directions for development of G/IAPPEs are presented. Development of a successful G/I APPE requires significant planning and consideration of appropriate qualifications for preceptors and students. PMID:27170810

  1. Electric field mediated colloidal assembly and control

    NASA Astrophysics Data System (ADS)

    Juarez, Jaime Javier

    2011-12-01

    This dissertation presents video microscopy measurements and computer simulations of colloidal particle interactions in inhomogeneous, high-frequency AC electric fields. The interactions of particles with each other and inhomogeneous electric fields are quantified as a function of concentration, field amplitude, and frequency. Visual state diagrams show that these interactions in concentrated systems produce quasi-two dimensional microstructures including confined hard disk fluids, oriented dipolar chains, and oriented hexagonal close packed crystals. The interaction of a particle interacting with an electric field is directly measured with analyses of a single diffusing colloid within electric fields in the absence of many body effects. Concentrated systems are characterized in terms of density profiles across the electrode gap and angular pair distribution functions. An inverse Monte Carlo analysis extracted the induced dipole-induced dipole interaction from concentrated measurements. A single adjustable parameter consistently modified the induced dipole-field potential and the induced dipole-induced dipole potential to account for modification of the local electric field as the result of the local particle concentration, frequency and configuration. Confocal laser scanning microscopy (CLSM) perform sensitive measurements of internal three dimensional structure of crystals assembled in an interfacial quadrupole electrode device. Radial distributions as functions of elevation are used to characterize the equilibrium structure. A single adjustable parameter modified known potentials to match Monte Carlo simulations with experiment. The local density from experiment and simulation matched the expected density calculated from a balance of osmotic pressure and dielectrophoretic compression. Simulations qualitatively matched experimental observations of microstructure as a function of field amplitude. Programmable assembly for colloidal crystals is implemented in the

  2. A Complex-Geometry Validation Experiment for Advanced Neutron Transport Codes

    SciTech Connect

    David W. Nigg; Anthony W. LaPorta; Joseph W. Nielsen; James Parry; Mark D. DeHart; Samuel E. Bays; William F. Skerjanc

    2013-11-01

    The Idaho National Laboratory (INL) has initiated a focused effort to upgrade legacy computational reactor physics software tools and protocols used for support of core fuel management and experiment management in the Advanced Test Reactor (ATR) and its companion critical facility (ATRC) at the INL.. This will be accomplished through the introduction of modern high-fidelity computational software and protocols, with appropriate new Verification and Validation (V&V) protocols, over the next 12-18 months. Stochastic and deterministic transport theory based reactor physics codes and nuclear data packages that support this effort include MCNP5[1], SCALE/KENO6[2], HELIOS[3], SCALE/NEWT[2], and ATTILA[4]. Furthermore, a capability for sensitivity analysis and uncertainty quantification based on the TSUNAMI[5] system has also been implemented. Finally, we are also evaluating the Serpent[6] and MC21[7] codes, as additional verification tools in the near term as well as for possible applications to full three-dimensional Monte Carlo based fuel management modeling in the longer term. On the experimental side, several new benchmark-quality code validation measurements based on neutron activation spectrometry have been conducted using the ATRC. Results for the first four experiments, focused on neutron spectrum measurements within the Northwest Large In-Pile Tube (NW LIPT) and in the core fuel elements surrounding the NW LIPT and the diametrically opposite Southeast IPT have been reported [8,9]. A fifth, very recent, experiment focused on detailed measurements of the element-to-element core power distribution is summarized here and examples of the use of the measured data for validation of corresponding MCNP5, HELIOS, NEWT, and Serpent computational models using modern least-square adjustment methods are provided.

  3. Colloidal Suspended Iron in Rivers

    NASA Astrophysics Data System (ADS)

    Shiller, A. M.

    2009-12-01

    Iron is transported in most rivers predominantly in two physical-chemical forms: a) organic complexes of Fe(III) and b) crystalline or poorly-ordered suspended phases frequently dominated by iron oxides. These two forms have different properties with respect to transport, bioavailability, and sorption. For the suspended phase iron, the fraction in the colloidal size range may be especially important given the interactions of ferric oxide surfaces with dissolved metal ions and organic compounds. We report the concentrations of colloidal (20 - 450 nm) suspended particulate iron in a wide variety of rivers. Goals of this effort are to ascertain the ubiquity of this material and also to examine other fluvial variables as indicators of its sources and nature. This, in turn, should lead to an understanding of how landscape/climate change could affect fluvial colloidal suspended iron. Possible sources of suspended colloidal iron include ferric oxides precipitated from the oxidation of ferrous iron derived from reducing environments, alumino-silicates derived from physical weathering, products of chemical weathering, and flushing of soils. We observe most commonly that increasing concentrations of colloidal suspended iron follow indicators of reducing sources (e.g., higher dissolved Mn and Ce anomaly close to 1), suggesting that this material is dominated by freshly precipitated iron oxides. Only in glacial watersheds do we find colloidal suspended iron instead correlating with colloidal suspended Si, and hence, likely to be associated with alumino-silicates. We also observe that colloidal suspended iron correlates well with the UV absorbance associated with this size range (20 - 450 nm).

  4. Re-shaping colloidal clusters

    NASA Astrophysics Data System (ADS)

    Kraft, Daniela

    2015-03-01

    Controlling the geometry and yield of anisotropic colloidal particles remains a challenge for hierarchical self-assembly. I will discuss a synthetic strategy for fabricating colloidal clusters by creating order in randomly aggregated polymer spheres using surface tension and geometrical constraints. The technique can be extended to a variety of charge-stabilized polymer spheres and offers control over the cluster size distribution. VENI grant from The Netherlands Organization for Scientific Research (NWO).

  5. Mechanical Failure in Colloidal Gels

    NASA Astrophysics Data System (ADS)

    Kodger, Thomas Edward

    When colloidal particles in a dispersion are made attractive, they aggregate into fractal clusters which grow to form a space-spanning network, or gel, even at low volume fractions. These gels are crucial to the rheological behavior of many personal care, food products and dispersion-based paints. The mechanical stability of these products relies on the stability of the colloidal gel network which acts as a scaffold to provide these products with desired mechanical properties and to prevent gravitational sedimentation of the dispersed components. Understanding the mechanical stability of such colloidal gels is thus of crucial importance to predict and control the properties of many soft solids. Once a colloidal gel forms, the heterogeneous structure bonded through weak physical interactions, is immediately subject to body forces, such as gravity, surface forces, such as adhesion to a container walls and shear forces; the interplay of these forces acting on the gel determines its stability. Even in the absence of external stresses, colloidal gels undergo internal rearrangements within the network that may cause the network structure to evolve gradually, in processes known as aging or coarsening or fail catastrophically, in a mechanical instability known as syneresis. Studying gel stability in the laboratory requires model colloidal system which may be tuned to eliminate these body or endogenous forces systematically. Using existing chemistry, I developed several systems to study delayed yielding by eliminating gravitational stresses through density matching and cyclic heating to induce attraction; and to study syneresis by eliminating adhesion to the container walls, altering the contact forces between colloids, and again, inducing gelation through heating. These results elucidate the varied yet concomitant mechanisms by which colloidal gels may locally or globally yield, but then reform due to the nature of the physical, or non-covalent, interactions which form

  6. Aggregation of Heterogeneously Charged Colloids.

    PubMed

    Dempster, Joshua M; Olvera de la Cruz, Monica

    2016-06-28

    Patchy colloids are attractive as programmable building blocks for metamaterials. Inverse patchy colloids, in which a charged surface is decorated with patches of the opposite charge, are additionally noteworthy as models for heterogeneously charged biological materials such as proteins. We study the phases and aggregation behavior of a single charged patch in an oppositely charged colloid with a single-site model. This single-patch inverse patchy colloid model shows a large number of phases when varying patch size. For large patch sizes we find ferroelectric crystals, while small patch sizes produce cross-linked gels. Intermediate values produce monodisperse clusters and unusual worm structures that preserve finite ratios of area to volume. The polarization observed at large patch sizes is robust under extreme disorder in patch size and shape. We examine phase-temperature dependence and coexistence curves and find that large patch sizes produce polarized liquids, in contrast to mean-field predictions. Finally, we introduce small numbers of unpatched charged colloids. These can either suppress or encourage aggregation depending on their concentration and the size of the patches on the patched colloids. These effects can be exploited to control aggregation and to measure effective patch size. PMID:27253725

  7. Nonequilibrium Equation of State in Suspensions of Active Colloids

    NASA Astrophysics Data System (ADS)

    Ginot, Félix; Theurkauff, Isaac; Levis, Demian; Ybert, Christophe; Bocquet, Lydéric; Berthier, Ludovic; Cottin-Bizonne, Cécile

    2015-01-01

    Active colloids constitute a novel class of materials composed of colloidal-scale particles locally converting chemical energy into motility, mimicking micro-organisms. Evolving far from equilibrium, these systems display structural organizations and dynamical properties distinct from thermalized colloidal assemblies. Harvesting the potential of this new class of systems requires the development of a conceptual framework to describe these intrinsically nonequilibrium systems. We use sedimentation experiments to probe the nonequilibrium equation of state of a bidimensional assembly of active Janus microspheres and conduct computer simulations of a model of self-propelled hard disks. Self-propulsion profoundly affects the equation of state, but these changes can be rationalized using equilibrium concepts. We show that active colloids behave, in the dilute limit, as an ideal gas with an activity-dependent effective temperature. At finite density, increasing the activity is similar to increasing adhesion between equilibrium particles. We quantify this effective adhesion and obtain a unique scaling law relating activity and effective adhesion in both experiments and simulations. Our results provide a new and efficient way to understand the emergence of novel phases of matter in active colloidal suspensions.

  8. Colloid mobilization in the field using citrate to remediate chromium.

    PubMed

    Johnson, C R; Hellerich, L A; Nikolaidis, N P; Gschwend, P M

    2001-01-01

    We investigated the feasibility of cleaning aquifer sediments, long contaminated with chromium (Cr) from a metal plating facility, by detaching colloid-sized sorbents from the immobile aquifer solids and then pumping those colloids to the surface for treatment. In laboratory experiments using aquifer solids from the site, several solutions (water at various pHs, phosphate, oxalate, ascorbate, citrate) were examined for their ability to disperse colloids and Cr. Based on these tests, a 5 mM citrate solution at pH 7 was selected. Subsequently, such a citrate solution was used in the field in two single-well injection-withdrawal experiments. Large quantities of colloids were released immediately after injection. The colloidal particles mobilized by citrate in the field had more than 20 times higher Cr concentrations than did the average aquifer sediments, implying success in mobilizing Cr-associated phases. Further, laboratory and field tests showed that anion exchange of citrate for chromate caused some additional release of Cr from these aquifer solids. PMID:11708455

  9. Early experience with digital advance care planning and directives, a novel consumer-driven program

    PubMed Central

    Yang, Zhiyong; Spivey, Christy; Boardman, Bonnie; Courtney, Maureen

    2016-01-01

    Barriers to traditional advance care planning (ACP) and advance directive (AD) creation have limited the promise of ACP/AD for individuals and families, the healthcare team, and society. Our objectives were to determine the results of a digital ACP/AD through which consumers create, store, locate, and retrieve their ACP/AD at no charge and with minimal physician involvement, and the ACP/AD can be integrated into the electronic health record. The authors chose 900 users of MyDirectives, a digital ACP/AD tool, to achieve proportional representation of all 50 states by population size and then reviewed their responses. The 900 participants had an average age of 50.8 years (SD = 16.6); 84% of the men and 91% of the women were in self-reported good health when signing their ADs. Among the respondents, 94% wanted their physicians to consult a supportive and palliative care team if they were seriously ill; nearly 85% preferred cessation of life-sustaining treatments during their final days; 76% preferred to spend their final days at home or in a hospice; and 70% would accept attempted cardiopulmonary resuscitation in limited circumstances. Most respondents wanted an autopsy under certain conditions, and 62% wished to donate their organs. In conclusion, analysis of early experience with this ACP/AD platform demonstrates that individuals of different ages and conditions can engage in an interrogatory process about values, develop ADs that are more nuanced than traditional paper-based ADs in reflecting those values, and easily make changes to their ADs. Online ADs have the potential to remove barriers to ACP/AD and thus further improve patient-centered end-of-life care. PMID:27365867

  10. Early experience with digital advance care planning and directives, a novel consumer-driven program.

    PubMed

    Fine, Robert L; Yang, Zhiyong; Spivey, Christy; Boardman, Bonnie; Courtney, Maureen

    2016-07-01

    Barriers to traditional advance care planning (ACP) and advance directive (AD) creation have limited the promise of ACP/AD for individuals and families, the healthcare team, and society. Our objectives were to determine the results of a digital ACP/AD through which consumers create, store, locate, and retrieve their ACP/AD at no charge and with minimal physician involvement, and the ACP/AD can be integrated into the electronic health record. The authors chose 900 users of MyDirectives, a digital ACP/AD tool, to achieve proportional representation of all 50 states by population size and then reviewed their responses. The 900 participants had an average age of 50.8 years (SD = 16.6); 84% of the men and 91% of the women were in self-reported good health when signing their ADs. Among the respondents, 94% wanted their physicians to consult a supportive and palliative care team if they were seriously ill; nearly 85% preferred cessation of life-sustaining treatments during their final days; 76% preferred to spend their final days at home or in a hospice; and 70% would accept attempted cardiopulmonary resuscitation in limited circumstances. Most respondents wanted an autopsy under certain conditions, and 62% wished to donate their organs. In conclusion, analysis of early experience with this ACP/AD platform demonstrates that individuals of different ages and conditions can engage in an interrogatory process about values, develop ADs that are more nuanced than traditional paper-based ADs in reflecting those values, and easily make changes to their ADs. Online ADs have the potential to remove barriers to ACP/AD and thus further improve patient-centered end-of-life care. PMID:27365867

  11. The Source Physics Experiments and Advances in Seismic Explosion Monitoring Predictive Capabilities

    NASA Astrophysics Data System (ADS)

    Walter, W. R.; Ford, S. R.; Antoun, T.; Pitarka, A.; Xu, H.; Vorobiev, O.; Rodgers, A.; Pyle, M. L.

    2012-12-01

    Despite many years of study, a number of seismic explosion phenomena remain incompletely understood. These include the generation of S-waves, the variation of absolute amplitudes with emplacement media differences, and the occasional generation of reversed Rayleigh waves. Advances in numerical methods and increased computational power have improved the physics contained in the modeling software and it is possible to couple non-linear source-region effects to far-field propagation codes to predict seismic observables, thereby allowing end-to-end modeling. However, despite the many sensor records from prior nuclear tests, the data available to develop and validate the simulation codes remain limited in important ways. This is particularly the case for the range of both scaled depths of burial and of source media, especially where full near-field to far-field records are available along with key quantitative parameter data such as depth, material properties and yield. For example, two of the most widely used seismic source models, both derived from the best empirical data, Mueller and Murphy (1971) and Denny and Johnson (1989), predict very different amplitudes for greatly overburied explosions. To provide new data to advance predictive explosion modeling capabilities, the National Nuclear Security Administration (NNSA) is carrying out a series of seven chemical explosions over a range of depths and sizes in the Source Physics Experiments (SPE). These shots are taking place in the Climax Stock granite at the Nevada National Security Site, the location where reversed Rayleigh waves from a nuclear test were first observed in the 1962 HARDHAT event (e.g. Brune and Pomeroy, 1963). Three of the SPE shots have successfully occurred so far, and were well-recorded by an extensive set of instrumentation including seismic, acoustic, EM, and remote sensing. In parallel, detailed site characterization has been conducted using geologic mapping and sampling, borehole geophysics

  12. Technology advancement for the ASCENDS mission using the ASCENDS CarbonHawk Experiment Simulator (ACES)

    NASA Astrophysics Data System (ADS)

    Obland, M. D.; Antill, C.; Browell, E. V.; Campbell, J. F.; CHEN, S.; Cleckner, C.; Dijoseph, M. S.; Harrison, F. W.; Ismail, S.; Lin, B.; Meadows, B. L.; Mills, C.; Nehrir, A. R.; Notari, A.; Prasad, N. S.; Kooi, S. A.; Vitullo, N.; Dobler, J. T.; Bender, J.; Blume, N.; Braun, M.; Horney, S.; McGregor, D.; Neal, M.; Shure, M.; Zaccheo, T.; Moore, B.; Crowell, S.; Rayner, P. J.; Welch, W.

    2013-12-01

    The ASCENDS CarbonHawk Experiment Simulator (ACES) is a NASA Langley Research Center project funded by NASA's Earth Science Technology Office that seeks to advance technologies critical to measuring atmospheric column carbon dioxide (CO2) mixing ratios in support of the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The technologies being advanced are: (1) multiple transmitter and telescope-aperture operations, (2) high-efficiency CO2 laser transmitters, (3) a high bandwidth detector and transimpedance amplifier (TIA), and (4) advanced algorithms for cloud and aerosol discrimination. The instrument architecture is being developed for ACES to operate on a high-altitude aircraft, and it will be directly scalable to meet the ASCENDS mission requirements. The above technologies are critical for developing an airborne simulator and spaceborne instrument with lower platform consumption of size, mass, and power, and with improved performance. This design employs several laser transmitters and telescope-apertures to demonstrate column CO2 retrievals with alignment of multiple laser beams in the far-field. ACES will transmit five laser beams: three from commercial lasers operating near 1.57-microns, and two from the Exelis atmospheric oxygen (O2) fiber laser amplifier system operating near 1.26-microns. The Master Oscillator Power Amplifier at 1.57-microns measures CO2 column concentrations using an Integrated-Path Differential Absorption (IPDA) lidar approach. O2 column amounts needed for calculating the CO2 mixing ratio will be retrieved using the Exelis laser system with a similar IPDA approach. The three aperture telescope design was built to meet the constraints of the Global Hawk high-altitude unmanned aerial vehicle (UAV). This assembly integrates fiber-coupled transmit collimators for all of the laser transmitters and fiber-coupled optical signals from the three telescopes to the aft optics and detector package. The detector

  13. Decreased Salinity and Actinide Mobility: Colloid-Facilitated Transport or pH Change?

    PubMed

    Haliena, Brian; Zheng, Hangping; Melson, Nathan; Kaplan, Daniel I; Barnett, Mark O

    2016-01-19

    Colloids have been implicated in influencing the transport of actinides and other adsorbed contaminants in the subsurface, significantly increasing their mobility. Such colloid-facilitated transport can be induced by changes in groundwater chemistry that occur, for example, when high ionic strength contaminant plumes are displaced by infiltrating rainwater. We studied the transport and mobility of Th(IV), as an analogue for Pu(IV) and other tetravalent actinides [An(IV)], in saturated columns packed with a natural heterogeneous subsurface sandy sediment. As expected, decreases in ionic strength both promoted the mobilization of natural colloids and enhanced the transport of previously adsorbed Th(IV). However, colloid-facilitated transport played only a minor role in enhancing the transport of Th(IV). Instead, the enhanced transport of Th(IV) was primarily due to the pH-dependent desorption of Th(IV) caused by the change in ionic strength. In contrast, the adsorption of Th(IV) had a marked impact on the surface charge of the sandy sediment, significantly affecting the mobility of the colloids. In the absence of Th(IV), changes in ionic strength were ineffective at releasing colloids while in the presence of Th(IV), decreases in ionic strength liberated significant concentrations of colloids. Therefore, under the conditions of our experiments which mimicked acidic, high ionic strength groundwater contaminant plumes, Th(IV) had a much greater effect on colloid transport than colloids had on Th(IV) transport. PMID:26687028

  14. Surface pressure isotherm for a monolayer of charged colloidal particles at a water/nonpolar-fluid interface: experiment and theoretical model.

    PubMed

    Petkov, Plamen V; Danov, Krassimir D; Kralchevsky, Peter A

    2014-03-18

    Monolayers from electrically charged micrometer-sized silica particles, spread on the air/water interface, are investigated. Because of the electrostatic repulsion, the distances between the particles are considerably greater than their diameters, i.e., we are dealing with nondensely packed interfacial layers. The electrostatic repulsion between the particles occurs through the air phase. Surface pressure vs area isotherms were measured by Langmuir trough, and the monolayers' morphology was monitored by microscope. The mean area per particle is determined by Delaunay triangulation and Voronoi diagrams. In terms of mean area, the surface pressure for monolayers from polydisperse and monodisperse particles obeys the same law. The experiments show that Π ∝ L(-3) at large L, where Π is the surface pressure and L is the mean interparticle distance. A theoretical cell model is developed, which predicts not only the aforementioned asymptotic law but also the whole Π(L) dependence. The model presumes a periodic distribution of the surface charge density, which induces a corresponding electric field in the air phase. Then, the Maxwell pressure tensor of the electric field in the air phase is calculated and integrated according to the Bakker's formula to determine the surface pressure. Thus, all collective effects from the electrostatic interparticle interactions are taken into account as well as the effects from the particle finite size. By evaporation of water, the particle monolayers are deposited on a solid substrate placed on the bottom of the trough. The electrostatic interparticle repulsion is strong enough to withstand the attractive lateral capillary immersion forces that are operative during the drying of the monolayer on the substrate. The obtained experimental results and the developed theoretical model can be useful for prediction and control of the properties of nondensely packed interfacial monolayers from charged particles that find applications for

  15. Colloid facilitated transport of lanthanides through discrete fractures in chalk

    NASA Astrophysics Data System (ADS)

    Tran, Emily; Klein Ben-David, Ofra; Teutsch, Nadya; Weisbrod, Noam

    2015-04-01

    transport rates and calculation of overall tracer recovery. Preliminary results suggest that mobility of Ce as a solute is negligible, and in experiments conducted without bentonite colloids, the 2% of the Ce that was recovered during the experiments travelled as "intrinsic" colloids in the form of Ce2(CO3)3-6H2O precipitate. However, the total recovery of the Ce increased to 9% when it was injected into the core in the presence of bentonite colloids and 13% when both bentonite and the carbonate precipitate colloids were injected. In addition, the maximum relative concentration (C/C0) of the Ce in the samples from the experiments conducted without bentonite colloids is about 0.002, whereas that of the experiments conducted in the presence of bentonite colloids reaches almost 0.2. This indicates that colloid presence does indeed markedly increase the mobility of radionuclides through fractured chalk matrices and should therefore be considered in models representing transport of radionuclide waste originating from nuclear repositories.

  16. Colloidal quantum dots entrained in microstructured optical fibers

    NASA Astrophysics Data System (ADS)

    Holton, Carvel E.; Meissner, Kenith E.; Herz, Erik; Kominsky, Daniel; Pickrell, Gary R.

    2004-06-01

    We present the initial results of entraining colloidal quantum dots emitting at wavelengths from 0.5um through 1.2um, in various micro-structured optical fibers. Conventional and non-conventional, micro-structured optical fibers fabricated at Virginia Tech"s Fiber & ElectroOptics Research Center (FEORC) have been combined with semiconductor, colloidal quantum dots fabricated by the VT Advanced Biomedical Center (VTabc). The results are presented primarily in the form of visual verification and analysis of entrainment phenomena, for a cross-section of colloidal dot and micro-structured fiber forms. Unique optical, electro-optical and material properties resulting from the combinations are visibly suggested in the results. Core/clad/free space propagation properties and effects of emitted and absorbed light fields are observed to be dependent on the structure, aspect ratio and materials of the fibers as well as the properties of the colloidal quantum dots. Basic spectral data on representative free-space materials will be presented in the current paper. The presentation will explore in passing, the research options available to such quantum dot-fiber combinations, including advanced sensors, sources and filters.

  17. Oppositely charged colloids out of equilibrium

    NASA Astrophysics Data System (ADS)

    Vissers, T.

    2010-11-01

    Colloids are particles with a size in the range of a few nanometers up to several micrometers. Similar to atomic and molecular systems, they can form gases, liquids, solids, gels and glasses. Colloids can be used as model systems because, unlike molecules, they are sufficiently large to be studied directly with light microscopy and move sufficiently slow to study their dynamics. In this thesis, we study binary systems of polymethylmethacrylate (PMMA) colloidal particles suspended in low-polar solvent mixtures. Since the ions can still partially dissociate, a surface charge builds up which causes electrostatic interactions between the colloids. By carefully tuning the conditions inside the suspension, we make two kinds of particles oppositely charged. To study our samples, we use Confocal Laser Scanning Microscopy (CLSM). The positively and negatively charged particles can be distinguished by a different fluorescent dye. Colloids constantly experience a random motion resulting from random kicks of surrounding solvent molecules. When the attractions between the oppositely charged particles are weak, the particles can attach and detach many times and explore a lot of possible configurations and the system can reach thermodynamic equilibrium. For example, colloidal ‘ionic’ crystals consisting of thousands to millions of particles can form under the right conditions. When the attractions are strong, the system can become kinetically trapped inside a gel-like state. We observe that when the interactions change again, crystals can even emerge again from this gel-like phase. By using local order parameters, we quantitatively study the crystallization of colloidal particles and identify growth defects inside the crystals. We also study the effect of gravity on the growth of ionic crystals by using a rotating stage. We find that sedimentation can completely inhibit crystal growth and plays an important role in crystallization from the gel-like state. The surface

  18. Thermoelectricity and thermodiffusion in charged colloids

    NASA Astrophysics Data System (ADS)

    Huang, B. T.; Roger, M.; Bonetti, M.; Salez, T. J.; Wiertel-Gasquet, C.; Dubois, E.; Cabreira Gomes, R.; Demouchy, G.; Mériguet, G.; Peyre, V.; Kouyaté, M.; Filomeno, C. L.; Depeyrot, J.; Tourinho, F. A.; Perzynski, R.; Nakamae, S.

    2015-08-01

    The Seebeck and Soret coefficients of ionically stabilized suspension of maghemite nanoparticles in dimethyl sulfoxide are experimentally studied as a function of nanoparticle volume fraction. In the presence of a temperature gradient, the charged colloidal nanoparticles experience both thermal drift due to their interactions with the solvent and electric forces proportional to the internal thermoelectric field. The resulting thermodiffusion of nanoparticles is observed through forced Rayleigh scattering measurements, while the thermoelectric field is accessed through voltage measurements in a thermocell. Both techniques provide independent estimates of nanoparticle's entropy of transfer as high as 82 meV K-1. Such a property may be used to improve the thermoelectric coefficients in liquid thermocells.

  19. Multiarm Star Polymers as Model Soft Colloids

    NASA Astrophysics Data System (ADS)

    Vlassopoulos, Dimitris

    2010-03-01

    Over the last decade, star polymers emerged as a useful model colloids that interpolate between polymers and hard sphere colloids. Together with microgels, they represent two benchmark soft colloidal systems, their internal structure being the key difference. Indeed, in the case of stars with open structure, the arms can interpenetrate in dense suspensions. The latter feature, that can be probed experimentally, is responsible for a number of interesting structural and dynamic properties of star polymers that set them apart from microgels. In this talk we present the basic properties of star polymers and focus on their extraordinary behavior in the highly concentrated regime, which is typically glassy. Our rheological and scattering experiments demonstrate unique features of the star glasses. Here we discuss two major ones: (i) Aging after pre-shear (the so-called rejuvenation) proceeds via a two-step process, associated with a fast arm engagement and a slow cooperative (cage) rearrangement. Remarkably, at extremely long times a steady state is observed and the terminal time in these systems can be experimentally accessible (and hence tailored at molecular level), as a consequence of the arms fluctuations. (ii) Multiple glassy states can be obtained when mixing stars with polymers or with other stars. Simultaneous theoretical and simulations work suggests that the softness is at the core of this unexpected behavior where depletion gives rise to glass melting and eventually re-entrant glasses are formed. Construction of a state diagram suggests kinetic pathways for tailoring the flow of soft colloids. These examples outline the importance of particle architecture on colloidal properties. Stars are a representative of a large class of hairy particles. The parallel important developments in mode coupling theory and its verses provide much needed predictive tools and rationalization for a number of phenomena such as those discussed here, as well as the complex

  20. BACH, the beamline for advanced dichroic and scattering experiments at ELETTRA

    NASA Astrophysics Data System (ADS)

    Zangrando, M.; Finazzi, M.; Paolucci, G.; Comelli, G.; Diviacco, B.; Walker, R. P.; Cocco, D.; Parmigiani, F.

    2001-02-01

    A beamline for advanced dichroism (BACH), to perform light polarization dependent experiments in the 35-1600 eV photon energy range is under construction at the ELETTRA Synchrotron Radiation Source in Trieste, Italy. The radiation source, based on two APPLE-II helical undulators, is designed for high photon flux and high resolving powers. The photons dispersion system is based on a Padmore variable angle spherical grating monochromator with a typical resolving power of 20 000-6000, 20 000-6000, and 15 000-5000 in the energy ranges 35-200 eV, 200-500 eV, and 500-1600 eV, respectively. Two separate branches after the monochromator allow setting two independent experimental chambers. The photon flux in the experimental chamber(s), calculated at the best resolutions achievable and with the aperture of the slits set at 10 μm, is expected to be above 1011 photons's with linearly or circularly polarized light. In addition, a fourth grating operates in the 400-1600 eV range to provide a higher flux, 1012 photons's with smaller resolving power (10 000-2000), allowing fluorescence and x-ray scattering experiments. The refocusing section(s), based on plane elliptical mirrors in a Kirkpatrick-Baez scheme, will provide on the sample, a nearly free-aberration spot(s), whose dimensions are expected to be 200×10 μm2 (horizontal×vertical). In the following, the general layout of the beamline is reported and the characteristics of the optical elements, as well as the optical performances (resolving powers and efficiencies of the monochromator, flux, and spot dimensions) are described in detail.

  1. An Evidence-based Medicine Elective Course to Improve Student Performance in Advanced Pharmacy Practice Experiences

    PubMed Central

    Rudisill, Celeste N.; Bickley, A. Rebecca; McAbee, Catherine; Miller, April D.; Piro, Christina C.; Schulz, Richard

    2011-01-01

    Objective To implement and evaluate the impact of an elective evidence-based medicine (EBM) course on student performance during advanced pharmacy practice experiences (APPEs). Design A 2-hour elective course was implemented using active-learning techniques including case studies and problem-based learning, journal club simulations, and student-driven wiki pages. The small class size (15 students) encouraged independent student learning, allowing students to serve as the instructors and guest faculty members from a variety of disciplines to facilitate discussions. Assessment Pre- and posttests found that students improved on 83% of the core evidence-based medicine concepts evaluated. Fifty-four APPE preceptors were surveyed to compare the performance of students who had completed the EBM course prior to starting their APPEs with students who had not. Of the 38 (70%) who responded, the majority (86.9%) agreed that students who had completed the course had stronger skills in applying evidence-based medicine to patient care than other students. The 14 students who completed the elective also were surveyed after completing their APPEs and the 11 who responded agreed the class had improved their skills and provided confidence in using the medical literature. Conclusions The skill set acquired from this EBM course improved students' performance in APPEs. Evidence-based medicine and literature search skills should receive more emphasis in the pharmacy curriculum. PMID:21451761

  2. The entrance system laboratory prototype for an advanced mass and ionic charge composition experiment

    SciTech Connect

    Allegrini, F.; Desai, M. I.; Livi, R.; Livi, S.; McComas, D. J.; Randol, B.

    2009-10-15

    Electrostatic analyzers (ESA) have been used extensively for the characterization of plasmas in a variety of space environments. They vary in shape, geometry, and size and are adapted to the specific particle population to be measured and the configuration of the spacecraft. Their main function is to select the energy per charge of the particles within a passband. An energy-per-charge range larger than that of the passband can be sampled by varying the voltage difference between the ESA electrodes. The voltage sweep takes time and reduces the duty cycle for a particular energy-per-charge passband. Our design approach for an advanced mass and ionic charge composition experiment (AMICCE) has a novel electrostatic analyzer that essentially serves as a spectrograph and selects ions simultaneously over a broad range of energy-per-charge (E/q). Only three voltage settings are required to cover the entire range from {approx}10 to 270 keV/q, thus dramatically increasing the product of the geometric factor times the duty cycle when compared with other instruments. In this paper, we describe the AMICCE concept with particular emphasis on the prototype of the entrance system (ESA and collimator), which we designed, developed, and tested. We also present comparisons of the laboratory results with electrostatic simulations.

  3. The Impact of Advanced Pharmacy Practice Experiences on Students' Readiness for Self-directed Learning

    PubMed Central

    Haines, Stuart T.; Plaza, Cecilia M.; Sturpe, Deborah A.; Williams, Greg; Rodriguez de Bittner, Magaly A.; Roffman, David S.

    2009-01-01

    Objective To evaluate the impact of advanced pharmacy practice experiences (APPEs) on doctor of pharmacy (PharmD) students' readiness for self-directed learning. Methods The Self-Directed Learning Readiness Scale (SDLRS) was administered to students prior to and after completing their APPEs. SDLRS is a validated instrument that determines the relative degree to which students have the attitudes and motivation to engage in self-directed learning. Results Seventy-seven (64%) students completed the SDLRS prior to starting their APPEs and 80 (67%) students completed the instrument after completing their APPEs. Forty-six (38%) students completed both. Prior to starting their APPEs, 74% of students scored greater than 150 on the SDLRS, indicating a high level of readiness for self-directed learning. No significant difference was found between the mean scores of students who took the SDLRS both prior to (159 ± 20) and after completing their APPEs (159 ± 24; p > 0.05). Conclusion Students at our institution appear to be ready for self-directed learning but APPEs had a minimal impact on their readiness for self-directed learning. PMID:19657498

  4. Quasi-static and dynamic responses of advanced high strength steels: Experiments and modeling

    SciTech Connect

    Khan, Akhtar; Baig, Muneer; Choi, Shi Hoon; Yang, Hoe Seok; Sun, Xin

    2012-03-01

    Measured responses of advanced high strength steels (AHSS) and their tailor welded blanks (TWBs), over a wide range of strain-rates (10*4 to 103 s*1) are presented. The steels investigated include transformation induced plasticity (TRIP), dual phase (DP), and drawing quality (DQ) steels. The TWBs include DQ-DQ and DP-DP laser welds. A tensile split Hopkinson pressure bar (SHPB) was used for the dynamic experiments. AHSS and their TWB's were found to exhibit positive strain-rate sensitivity. The Khan-Huang-Liang (KHL) constitutive model is shown to correlate and predict the observed responses reasonably well. Micro-texture characterization of DQ steels, DQ-DQ and DP-DP laser welds were performed to investigate the effect of strain-rate on texture evolution of these materials. Electron backscatter diffraction (EBSD) technique was used to analyze the micro-texture evolution and kernel average misorientation (KAM) map. Measurement of micro-hardness profile across the cross section of tensile samples was conducted to understand the effect of initial microstructure on ductility of laser weld samples.

  5. Flame experiments at the advanced light source: new insights into soot formation processes.

    PubMed

    Hansen, Nils; Skeen, Scott A; Michelsen, Hope A; Wilson, Kevin R; Kohse-Höinghaus, Katharina

    2014-01-01

    The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory(1-4). This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range(5,6). The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species' profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates(7). The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles(4). The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation

  6. Flame Experiments at the Advanced Light Source: New Insights into Soot Formation Processes

    PubMed Central

    Hansen, Nils; Skeen, Scott A.; Michelsen, Hope A.; Wilson, Kevin R.; Kohse-Höinghaus, Katharina

    2014-01-01

    The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species’ profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the

  7. Using an Advanced Computational Laboratory Experiment to Extend and Deepen Physical Chemistry Students' Understanding of Atomic Structure

    ERIC Educational Resources Information Center

    Hoffman, Gary G.

    2015-01-01

    A computational laboratory experiment is described, which involves the advanced study of an atomic system. The students use concepts and techniques typically covered in a physical chemistry course but extend those concepts and techniques to more complex situations. The students get a chance to explore the study of atomic states and perform…

  8. An Advanced Analytical Chemistry Experiment Using Gas Chromatography-Mass Spectrometry, MATLAB, and Chemometrics to Predict Biodiesel Blend Percent Composition

    ERIC Educational Resources Information Center

    Pierce, Karisa M.; Schale, Stephen P.; Le, Trang M.; Larson, Joel C.

    2011-01-01

    We present a laboratory experiment for an advanced analytical chemistry course where we first focus on the chemometric technique partial least-squares (PLS) analysis applied to one-dimensional (1D) total-ion-current gas chromatography-mass spectrometry (GC-TIC) separations of biodiesel blends. Then, we focus on n-way PLS (n-PLS) applied to…

  9. Computer experiments on periodic systems identification using rotor blade transient flapping-torsion responses at high advance ratio

    NASA Technical Reports Server (NTRS)

    Hohenemser, K. H.; Prelewicz, D. A.

    1974-01-01

    Systems identification methods have recently been applied to rotorcraft to estimate stability derivatives from transient flight control response data. While these applications assumed a linear constant coefficient representation of the rotorcraft, the computer experiments described in this paper used transient responses in flap-bending and torsion of a rotor blade at high advance ratio which is a rapidly time varying periodic system.

  10. The Advanced Interdisciplinary Research Laboratory: A Student Team Approach to the Fourth-Year Research Thesis Project Experience

    ERIC Educational Resources Information Center

    Piunno, Paul A. E.; Boyd, Cleo; Barzda, Virginijus; Gradinaru, Claudiu C.; Krull, Ulrich J.; Stefanovic, Sasa; Stewart, Bryan

    2014-01-01

    The advanced interdisciplinary research laboratory (AIRLab) represents a novel, effective, and motivational course designed from the interdisciplinary research interests of chemistry, physics, biology, and education development faculty members as an alternative to the independent thesis project experience. Student teams are assembled to work…

  11. Synthesis of Di- and Trisubstituted Azulenes Using a Danheiser Annulation as the Key Step: An Advanced Organic Laboratory Experiment

    ERIC Educational Resources Information Center

    Thomas, Rebecca M.; Shea, Kevin M.

    2013-01-01

    This three-week advanced-level organic experiment provides students with an inquiry-based approach focused on learning traditional skills such as primary literature interpretation, reaction design, flash column chromatography, and NMR analysis. Additionally, students address higher-order concepts such as the origin of azulene's blue color,…

  12. Introduction to Homogenous Catalysis with Ruthenium-Catalyzed Oxidation of Alcohols: An Experiment for Undergraduate Advanced Inorganic Chemistry Students

    ERIC Educational Resources Information Center

    Miecznikowski, John R.; Caradonna, John P.; Foley, Kathleen M.; Kwiecien, Daniel J.; Lisi, George P.; Martinez, Anthony M.

    2011-01-01

    A three-week laboratory experiment, which introduces students in an advanced inorganic chemistry course to air-sensitive chemistry and catalysis, is described. During the first week, the students synthesize RuCl[subscript 2](PPh[subscript 3])[subscript 3]. During the second and third weeks, the students characterize the formed coordination…

  13. Brownian colloidal particles: Ito, Stratonovich, or a different stochastic interpretation

    NASA Astrophysics Data System (ADS)

    Sancho, J. M.

    2011-12-01

    Recent experiments on Brownian colloidal particles have been studied theoretically in terms of overdamped Langevin equations with multiplicative white noise using an unconventional stochastic interpretation. Complementary numerical simulations of the same system are well described using the conventional Stratonovich interpretation. Here we address this dichotomy from a more generic starting point: the underdamped Langevin equation and its corresponding Fokker-Planck equation.

  14. Physics of Colloids in Space (PCS) Flight Hardware Developed

    NASA Technical Reports Server (NTRS)

    Koudelka, John M.

    2001-01-01

    investigation that will be located in an Expedite the Process of Experiments to Space Station (EXPRESS) Rack. The investigation will be conducted in the International Space Station U.S. laboratory, Destiny, over a period of approximately 10 months during the station assembly period from flight 6A through flight UF-2. This experiment will gather data on the basic physical properties of colloids by studying three different colloid systems with the objective of understanding how they grow and what structures they form. A colloidal suspension consists of fine particles (micrometer to submicrometer) suspended in a fluid for example, paints, milk, salad dressings, and aerosols. The long-term goal of this investigation is to learn how to steer the growth of colloidal suspensions to create new materials and new structures. This experiment is part of a two-stage investigation conceived by Professor David Weitz of Harvard University along with Professor Peter Pusey of the University of Edinburgh. The experiment hardware was developed by the NASA Glenn Research Center through contracts with Dynacs, Inc., and ZIN Technologies.

  15. Quantitatively mimicking wet colloidal suspensions with dry granular media.

    PubMed

    Messina, René; Aljawhari, Sarah; Bécu, Lydiane; Schockmel, Julien; Lumay, Geoffroy; Vandewalle, Nicolas

    2015-01-01

    Athermal two-dimensional granular systems are exposed to external mechanical noise leading to Brownian-like motion. Using tunable repulsive interparticle interaction, it is shown that the same microstructure as that observed in colloidal suspensions can be quantitatively recovered at a macroscopic scale. To that end, experiments on granular and colloidal systems made up of magnetized particles as well as computer simulations are performed and compared. Excellent agreement throughout the range of the magnetic coupling parameter is found for the pair distribution as well as the bond-orientational correlation functions. This finding opens new ways to efficiently and very conveniently explore phase transitions, crystallization, nucleation, etc in confined geometries. PMID:26030718

  16. Some implications of colloid stability theory for protein crystallization

    NASA Technical Reports Server (NTRS)

    Young, C. C.; De Mattei, R. C.; Feigelson, R. S.; Tiller, W. A.

    1988-01-01

    Colloid stability theory has been applied to protein crystallization and predicts a narrow range of conditions under which crystals can be grown without the agglomeration of protein molecules (colloids) in the bulk solution. It also predicts a critical electrolyte concentration above which agglomeration will always occur. Using this theory, the rapid protein agglomeration occurring during Schlieren experiments as well as a terminal crystal size effect in a fixed container were explained. Following this concept, the supposed 'terminal' crystal size has been at least doubled.

  17. Colloids as model systems for liquid undercooled metals

    NASA Astrophysics Data System (ADS)

    Wette, Patrick; Klassen, Ina; Holland-Moritz, Dirk; Palberg, Thomas; Roth, Stephan V.; Herlach, Dieter M.

    2009-01-01

    Charged colloidal particles interact via a hard core Yukawa potential, while isotropic Lennard-Jones-like potentials are frequently used as pair potentials in metals. We present measurements of the structure factor of shear molten monodisperse colloids and molten metals using ultrasmall-angle x-ray scattering and elastic neutron scattering, respectively. In both systems data analysis gives evidence of fivefold-symmetric short-range order becoming more pronounced with increasing deviations from equilibrium. The experiments demonstrate that in both systems topological effects control ordering in the melt state.

  18. Internal Dynamics of Equilibrium Colloidal Clusters

    NASA Astrophysics Data System (ADS)

    Perry, Rebecca Wood

    interactions. We find that the interactions allow for control over the intracluster placement of each species, while the masses have no influence. To provide a theoretical framework for understanding these observations, we derive the classical partition function of colloidal clusters in terms of translational, rotational, and vibrational degrees of freedom. We show that the masses of the particles enter the partition function through the kinetic energy but have no effect on the probabilities of states that differ only in where the masses are placed. This result is consistent with our experiments. Overall, this work shows that the equilibrium distribution of self-assembled colloidal clusters is well-modeled by classical statistical physics, and that the rearrangement dynamics of colloidal clusters can be understood by incorporating diffusion and the effect of the interaction potential. Because both the structures and dynamics can be accurately predicted, these clusters are a promising system for self-assembling novel materials and for studying the emergence of phase transitions.

  19. Reconfigurable multi-scale colloidal assembly on excluded volume patterns

    PubMed Central

    Edwards, Tara D.; Yang, Yuguang; Everett, W. Neil; Bevan, Michael A.

    2015-01-01

    The ability to create multi-scale, periodic colloidal assemblies with unique properties is important to emerging applications. Dynamically manipulating colloidal structures via tunable kT-scale attraction can provide the opportunity to create particle-based nano- and microstructured materials that are reconfigurable. Here, we report a novel tactic to obtain reconfigurable, multi-scale, periodic colloidal assemblies by combining thermoresponsive depletant particles and patterned topographical features that, together, reversibly mediate local kT-scale depletion interactions. This method is demonstrated in optical microscopy experiments to produce colloidal microstructures that reconfigure between well-defined ordered structures and disordered fluid states as a function of temperature and pattern feature depth. These results are well described by Monte Carlo simulations using theoretical depletion potentials that include patterned excluded volume. Ultimately, the approach reported here can be extended to control the size, shape, orientation, and microstructure of colloidal assemblies on multiple lengths scales and on arbitrary pre-defined pattern templates. PMID:26330058

  20. Reconfigurable multi-scale colloidal assembly on excluded volume patterns.

    PubMed

    Edwards, Tara D; Yang, Yuguang; Everett, W Neil; Bevan, Michael A

    2015-01-01

    The ability to create multi-scale, periodic colloidal assemblies with unique properties is important to emerging applications. Dynamically manipulating colloidal structures via tunable kT-scale attraction can provide the opportunity to create particle-based nano- and microstructured materials that are reconfigurable. Here, we report a novel tactic to obtain reconfigurable, multi-scale, periodic colloidal assemblies by combining thermoresponsive depletant particles and patterned topographical features that, together, reversibly mediate local kT-scale depletion interactions. This method is demonstrated in optical microscopy experiments to produce colloidal microstructures that reconfigure between well-defined ordered structures and disordered fluid states as a function of temperature and pattern feature depth. These results are well described by Monte Carlo simulations using theoretical depletion potentials that include patterned excluded volume. Ultimately, the approach reported here can be extended to control the size, shape, orientation, and microstructure of colloidal assemblies on multiple lengths scales and on arbitrary pre-defined pattern templates. PMID:26330058

  1. Dielectrophoresis force of colloidal nanoparticles

    NASA Astrophysics Data System (ADS)

    Huang, Hao; Ou-Yang, Daniel

    Dielectrophoresis (DEP) is the motion of a polarizable colloidal particle in a non­uniform electric field. The magnitude of the DEP force is known to be proportional to the gradient of E2. The DEP force also depends on the relative polarizability of the particle to that of the surrounding medium. Due to its ease of use, DEP has been proposed for a variety of applications to manipulate colloidal particles in a microfluidic setting. However, accurate measurements of the DEP force on colloidal nanoparticles are lacking. A new method is proposed to measure accurately the DEP potential force of colloidal nanoparticles by using confocal fluorescence imaging to determine the density distributions of dilute colloidal nanoparticle in a DEP potential force field. The DEP potential field can be calculated from the particle density distributions since the spatial distribution of the particle number density follows the Boltzmann distribution of the DEP potential energy. The validity of the measured DEP force is tested by examining the force as a function of the E field strength and particle size. The classic Maxwell­Wagner­O'Konski is found to be inadequate to fully describe the frequency dependence of the DEP force. NSF 0928299, Emulsion Polymer Institute, Department of Physics of Lehigh University.

  2. Pairwise interactions of colloids in two-dimensional geometric confinement.

    PubMed

    Park, Bum Jun; Lee, Bomsock; Yu, Taekyung

    2014-12-28

    We present the pairwise interaction behaviour of colloids confined to two-dimensional (2D) colloidal cages using optical laser tweezers. A single probe particle inside hexagonal cage particles at a planar oil-water interface is allowed to diffuse freely and the spring constant is extracted from its trajectories. To evaluate the effect of multibody interactions, the pair interactions between the probe particle and each cage particle are directly measured by using optical tweezers. Based on pairwise additivity, Monte Carlo simulations are used to compare the values of the spring constant obtained from experiments and simulations. We find that the multibody interactions negligibly occur and thus the particle interactions confined to such colloidal cages are highly pairwise. This work demonstrates that the use of the pairwise assumption in numerical simulations is rational when interparticle repulsive interactions are sufficiently strong, such as the particle interactions at fluid-fluid interfaces. PMID:25363564

  3. Crystalline Colloidal Arrays in Polymer Matrices

    NASA Technical Reports Server (NTRS)

    Sunkara, Hari B.; Penn, B. G.; Frazier, D. O.; Ramachandran, N.

    1997-01-01

    Crystalline Colloidal Arrays (CCA, also known as colloidal crystals), composed of aqueous or nonaqueous dispersions of self-assembled nanosized polymer colloidal spheres, are emerging toward the development of advanced optical devices for technological applications. The spontaneous self assembly of polymer spheres in a dielectric medium results from the electrostatic repulsive interaction between particles of uniform size and charge distribution. In a way similar to atomic crystals that diffract X-rays, CCA dispersions in thin quartz cells selectively and efficiently Bragg diffract the incident visible light. The reason for this diffraction is because the lattice (body or face centered cubic) spacing is on the order of the wavelength of visible light. Unlike the atomic crystals that diffract a fixed wavelength, colloidal crystals in principle, depending on the particle size, particle number and charge density, can diffract W, Vis or IR light. Therefore, the CCA dispersions can be used as laser filters. Besides, the diffraction intensity depends on the refractive index mismatch between polymer spheres and dielectric medium; therefore, it is possible to modulate incident light intensities by manipulating the index of either the spheres or the medium. Our interest in CCA is in the fabrication of all-optical devices such as optical switches, limiters, and spatial light modulators for optical signal processing. The two major requirements from a materials standpoint are the incorporation of suitable nonlinear optical materials (NLO) into polymer spheres which will allow us to alter the refractive index of the spheres by intense laser radiation, and preparation of solid CCA filters which can resist laser damage. The fabrication of solid composite filters not only has the advantage that the films are easier to handle, but also the arrays in solid films are more robust than in liquid media. In this paper, we report the photopolymerization process used to trap CCA in polymer

  4. Final Assembly and Initial Irradiation of the First Advanced Gas Reactor Fuel Development and Qualification Experiment in the Advanced Test Reactor

    SciTech Connect

    S. B. Grover

    2007-05-01

    The United States Department of Energy’s Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating eight separate low enriched uranium (LEU) oxycarbide (UCO) tri-isotropic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the new United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The AGR fuel experiments will be irradiated over the next ten years to demonstrate and qualify new particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing.1,2 The experiments, which will each consist of six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The final design phase for the first experiment was completed in 2005, and the fabrication and assembly of the first experiment test train (designated AGR-1) as well as the support systems and fission product monitoring system that will monitor and control the experiment

  5. Delayed yield in reversible colloidal gels: a micro- mechanical perspective

    NASA Astrophysics Data System (ADS)

    Zia, Roseanna; Landrum, Benjamin; Russel, William

    2015-11-01

    We study via dynamic simulation the nonlinear response of a reversible colloidal gel undergoing deformation under fixed stress, with a view toward elucidating mechanisms of macroscopic yield at the level of particle dynamics. Under shear, such gels may flow but then regain solidlike behavior upon removal of the stress. The transition from solidlike to liquidlike behavior is a yielding process that is not instantaneous but rather occurs after a finite delay. The delay duration decreases as stress increases, but the underlying microstructural origins are not understood. Recent experiments reveal two regimes, suggesting multiple yield mechanisms. Theories advanced to link gel structure to this rheology hypothesize a competition between bond breakage and reconnection rates, but no such particle-scale dynamics have been directly observed - or reconciled with ongoing structural evolution. To study these behaviors, we impose a step stress on a gel comprising 750,000 Brownian particles for a range of volume fraction, attraction strength, and imposed stress, monitoring displacement and particle velocity over time. A detailed connection between macroscopic response, microstructure, and particle dynamics leads to a phase map predicting nonlinear response of such gels to fixed stress.

  6. Crack formation and prevention in colloidal drops.

    PubMed

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A; Kim, So Youn; Weon, Byung Mook

    2015-01-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles. PMID:26279317

  7. Crack formation and prevention in colloidal drops

    NASA Astrophysics Data System (ADS)

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A.; Kim, So Youn; Weon, Byung Mook

    2015-08-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles.

  8. Crack formation and prevention in colloidal drops

    PubMed Central

    Kim, Jin Young; Cho, Kun; Ryu, Seul-a; Kim, So Youn; Weon, Byung Mook

    2015-01-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles. PMID:26279317

  9. Organic nature of colloidal actinides transported in surface water environments.

    PubMed

    Santschi, Peter H; Roberts, Kimberly A; Guo, Laodong

    2002-09-01

    Elevated levels of (239,240)Pu and 241Am have been present in surficial soils of the Rocky Flats Environmental Technology Site (RFETS), CO, since the 1960s, when soils were locally contaminated in the 1960s by leaking drums stored on the 903 Pad. Further dispersion of contaminated soil particles was by wind and water. From 1998 until 2001, we examined actinide ((239,240)Pu and 241Am) concentrations and phase speciation in the surface environment at RFETS through field studies and laboratory experiments. Measurements of total (239,240)Pu and 241Am concentrations in storm runoff and pond discharge samples, collected during spring and summer times in 1998-2000, demonstrate that most of the (239,240)Pu and 241Am transported from contaminated soils to streams occurred in the particulate (> or = 0.45 microm; 40-90%) and colloidal (approximately 2 nm or 3 kDa to 0.45 microm; 10-60%) phases. Controlled laboratory investigations of soil resuspension, which simulated storm and erosion events, confirmed that most of the Pu in the 0.45 microm filter-passing phase was in the colloidal phase (> or = 80%) and that remobilization of colloid-bound Pu during soil erosion events can be greatly enhanced by humic and fulvic acids present in these soils. Most importantly, isoelectric focusing experiments of radiolabeled colloidal matter extracted from RFETS soils revealed that colloidal Pu is in the four-valent state and is mostly associated with a negatively charged organic macromolecule with a pH(IEP) of 3.1 and a molecular weight of 10-15 kDa, rather than with the more abundant inorganic (iron oxide and clay) colloids. This finding has important ramifications for possible remediation, erosion controls, and land-management strategies. PMID:12322742

  10. Doped colloidal artificial spin ice

    NASA Astrophysics Data System (ADS)

    Libál, A.; Olson Reichhardt, C. J.; Reichhardt, C.

    2015-10-01

    We examine square and kagome artificial spin ice for colloids confined in arrays of double-well traps. Unlike magnetic artificial spin ices, colloidal and vortex artificial spin ice realizations allow creation of doping sites through double occupation of individual traps. We find that doping square and kagome ice geometries produces opposite effects. For square ice, doping creates local excitations in the ground state configuration that produce a local melting effect as the temperature is raised. In contrast, the kagome ice ground state can absorb the doping charge without generating non-ground-state excitations, while at elevated temperatures the hopping of individual colloids is suppressed near the doping sites. These results indicate that in the square ice, doping adds degeneracy to the ordered ground state and creates local weak spots, while in the kagome ice, which has a highly degenerate ground state, doping locally decreases the degeneracy and creates local hard regions.

  11. Polymeric stabilization of colloidal asphaltenes

    NASA Astrophysics Data System (ADS)

    Hashmi, Sara; Firoozabadi, Abbas

    2010-03-01

    Asphaltenes, the heaviest component of crude oil, cause many problems in petroleum extraction and recovery. Operationally defined as insoluble in long chain alkanes but soluble in toluene, asphaltenes have been described by bulk thermodynamic models such as the Flory-Huggins theory. However, bulk models work well only for asphaltenes in good solvents. Characterization of asphaltenes in poor solvents remains elusive: molecular scale asphaltenes readily aggregate to the colloidal scale and become highly unstable in solution. We investigate the ability of polymers to stabilize colloidal asphaltene suspensions in heptane. In the absence of added polymer, sedimentation measurements reveal dynamics reminiscent of collapsing gels. Adding polymers to colloidal asphaltene suspensions can delay the characteristic sedimentation time by orders of magnitude. Light scattering results suggest that the mechanism of stabilization may be related to a decrease in both particle size and polydispersity as a function of added polymer.

  12. Gel transitions in colloidal suspensions

    NASA Astrophysics Data System (ADS)

    Bergenholtz, J.; Fuchs, M.

    1999-12-01

    The idealized mode-coupling theory (MCT) is applied to colloidal systems interacting via short-range attractive interactions of Yukawa form. At low temperatures, MCT predicts a slowing down of the local dynamics and ergodicity-breaking transitions. The non-ergodicity transitions share many features with the colloidal gel transition, and are proposed to be the source of gelation in colloidal systems. Previous calculations of the phase diagram are complemented with additional data for shorter ranges of the attractive interaction, showing that the path of the non-ergodicity transition line is then unimpeded by the gas-liquid critical curve at low temperatures. Particular attention is given to the critical non-ergodicity parameters; this is motivated by recent experimental measurements. An asymptotic model is developed, valid for dilute systems of spheres interacting via strong short-range attractions, and is shown to capture all aspects of the low-temperature MCT non-ergodicity transitions.

  13. Advanced light source vacuum policy and vacuum guidelines for beamlines and experiment endstations

    SciTech Connect

    Hussain, Z.

    1995-08-01

    The purpose of this document is to: (1) Explain the ALS vacuum policy and specifications for beamlines and experiment endstations. (2) Provide guidelines related to ALS vacuum policy to assist in designing beamlines which are in accordance with ALS vacuum policy. This document supersedes LSBL-116. The Advanced Light Source is a third generation synchrotron radiation source whose beam lifetime depends on the quality of the vacuum in the storage ring and the connecting beamlines. The storage ring and most of the beamlines share a common vacuum and are operated under ultra-high-vacuum (UHV) conditions. All endstations and beamline equipment must be operated so as to avoid contamination of beamline components, and must include proper safeguards to protect the storage ring vacuum from an accidental break in the beamline or endstation vacuum systems. The primary gas load during operation is due to thermal desorption and electron/photon induced desorption of contaminants from the interior of the vacuum vessel and its components. The desorption rates are considerably higher for hydrocarbon contamination, thus considerable emphasis is placed on eliminating these sources of contaminants. All vacuum components in a beamline and endstation must meet the ALS vacuum specifications. The vacuum design of both beamlines and endstations must be approved by the ALS Beamline Review Committee (BRC) before vacuum connections to the storage ring are made. The vacuum design is first checked during the Beamline Design Review (BDR) held before construction of the beamline equipment begins. Any deviation from the ALS vacuum specifications must be approved by the BRC prior to installation of the equipment on the ALS floor. Any modification that is incorporated into a vacuum assembly without the written approval of the BRC is done at the user`s risk and may lead to rejection of the whole assembly.

  14. Cooling Properties of the Shuttle Advanced Crew Escape Spacesuit: Results of an Environmental Chamber Experiment

    NASA Technical Reports Server (NTRS)

    Hamilton, Douglas; Gillis, David; Bue, Grant; Son, Chan; Norcross, Jason; Kuznetz, Larry; Chapman, Kirt; Chhipwadia, Ketan; McBride, Tim

    2008-01-01

    The shuttle crew wears the Advanced Crew Escape Spacesuit (ACES) to protect themselves from cabin decompression and to support bail out during landing. ACES is cooled by a liquid-cooled garment (LCG) that interfaces to a heat exchanger that dumps heat into the cabin. The ACES outer layer is made of Gore-Tex(Registered TradeMark), permitting water vapor to escape while containing oxygen. The crew can only lose heat via insensible water losses and the LCG. Under nominal landing operations, the average cabin temperature rarely exceeds 75 F, which is adequate for the ACES to function. Problem A rescue shuttle will need to return 11 crew members if the previous mission suffers a thermal protection system failure, preventing it from returning safely to Earth. Initial analysis revealed that 11 crew members in the shuttle will increase cabin temperature at wheel stop above 80 F, which decreases the ACES ability to keep crew members cool. Air flow in the middeck of the shuttle is inhomogeneous and some ACES may experience much higher temperatures that could cause excessive thermal stress to crew members. Methods A ground study was conducted to measure the cooling efficiency of the ACES at 75 F, 85 F, and 95 F at 50% relative humidity. Test subjects representing 5, 50, and 95 percentile body habitus of the astronaut corps performed hand ergometry keeping their metabolic rate at 400, 600, and 800 BTU/hr for one hour. Core temperature was measured by rectal probe and skin, while inside and outside the suit. Environmental chamber wall and cooling unit inlet and outlet temperatures were measured using high-resolution thermistors ( 0.2 C). Conclusions Under these test conditions, the ACES was able to protect the core temperature of all test subjects, however thermal stress due to high insensible losses and skin temperature and skin heat flow may impact crew performance. Further research should be performed to understand the impact on cognitive performance.

  15. Gender Differences in Classroom Participation and Achievement: An Experiment Involving Advanced Placement Calculus Classes.

    ERIC Educational Resources Information Center

    Subotnik, Rena F.; Strauss, Shiela M.

    1995-01-01

    Despite scoring lower on the mathematics Scholastic Assessment Test (SAT-M) prior to taking an advanced placement calculus course, female students (n=85) scored as well as males (n=51) on the Advanced Placement BC level calculus test. Predictors of AP scores were: first, scores on the Calculus Readiness Test; second, scores on the SAT-M; and…

  16. "Something's Gotta Give:" Advanced-Degree Seeking Women's Experiences of Sexism, Role Overload, and Psychological Distress

    ERIC Educational Resources Information Center

    West, Lindsey M.

    2014-01-01

    With the rise in advanced-degree seeking women and the minimal research on the dual impact of sexism and role overload, the current study aims to better understand the impact of sexism and role overload on psychological distress in a particular sample of advanced-degree seeking women. Seventy-six female medical student participants (mean age 24.7)…

  17. COLLOID-FACILITATED TRANSPORT OF RADIONUCLIDES THROUGH THE VADOSE ZONE

    SciTech Connect

    Flury, Markus

    2003-09-14

    Contaminants have leaked into the vadose zone at the USDOE Hanford reservation. It is important to understand the fate and transport of these contaminants to design remediation strategies and long-term waste management plans at the Hanford reservation. Colloids may play an important role in fate and transport of strongly sorbing contaminants, such as Cs or Pu. This project seeks to improve the basic understanding of colloid and colloid-facilitated transport of contaminants in the vadose zone. The specific objectives addressed are: (1) Determine the structure, composition, and surface charge characteristics of colloidal particles formed under conditions similar to those occurring during leakage of waste typical of Hanford tank supernatants into soils and sediments surrounding the tanks. (2) Characterize the mutual interactions between colloids, contaminant, and soil matrix in batch experiments under various ionic strength and pH conditions. We will investigate the nature of the solid-liquid interactions and the kinetics of the reactions. (3) Evaluate mobility of colloids through soil under different degrees of water saturation and solution chemistry (ionic strength and pH). (4) Determine the potential of colloids to act as carriers to transport the contaminant through the vadose zone and verify the results through comparison with field samples collected under leaking tanks. (5) Improve conceptual characterization of colloid-contaminant-soil interactions and colloid-facilitated transport for implementation into reactive chemical transport models. This project was in part supported by an NSF-IGERT grant to Washington State University. The IGERT grant provided funding for graduate student research and education, and two graduate students were involved in the EMSP project. The IGERT program also supported undergraduate internships. The project is part of a larger EMSP program to study fate and transport of contaminants under leaking Hanford waste tanks. The project has

  18. Experimental studies of contact networks in jammed colloidal systems

    NASA Astrophysics Data System (ADS)

    Kyeyune-Nyombi, Eru; Gilchrist, Lane; Makse, Hernán

    Recent theoretical advances in the statistical mechanics of jamming have provided a new outlook for thermodynamically characterizing packings of granular matter. Packing density, spatial ordering metrics, and the number of inter-particle contacts are a few fundamental parameters used in various theoretical models. However, experimental measurements of inter-particle forces have been illusive. Here, fluorescent molecular probes are used to identify inter-particle contacts in high resolution confocal images of jammed colloidal systems.

  19. Colloidal particle assembly using piezoelectric inkjet printing of polystyrene colloidal ink formulations.

    PubMed

    Kwon, Younghwan

    2014-10-01

    We report the feasibility of piezoelectric inkjet printing of colloidal dispersion inks for geometrical patterning to arrange colloids in desired locations. Polystyrene colloid (dia. = 3 μm) inks dispersed with thermally curable binder in organic solvents are explored for fundamental study on colloidal patterning. The inkjet printability of colloidal inks is systematically investigated with different ink formulations and inkjet process variables. In addition, in order to maintain the structural stability of colloidal patterns fabricated on the substrate from externally applied forces such as mechanical, chemical and thermal stimuli, thermally curable binder was formulated into the colloidal ink formulations. PMID:25942838

  20. A survey of stakeholder knowledge, experience, and opinions of advance directives for mental health in Virginia.

    PubMed

    Wilder, Christine M; Swanson, Jeffrey W; Bonnie, Richard J; Wanchek, Tanya; McLaughlin, Laura; Richardson, Jeanita

    2013-05-01

    An innovative Virginia health care law enables competent adults with serious mental illness to plan for treatment during incapacitating crises using an integrated advance directive with no legal distinction between psychiatric or other causes of decisional incapacity. This article reports results of a survey of 460 individuals in five stakeholder groups during the initial period of the law's implementation. All respondents held favorable views of advance directives for mental health care. Identified barriers to completing and using advance directives varied by group. We conclude that relevant stakeholders support implementation of advance directives for mental health, but level of baseline knowledge and perception of barriers vary. A multi-pronged approach will be needed to achieve successful implementation of advance directives for mental health. PMID:22240937

  1. Narrow bandgap colloidal metal chalcogenide quantum dots: synthetic methods, heterostructures, assemblies, electronic and infrared optical properties.

    PubMed

    Kershaw, Stephen V; Susha, Andrei S; Rogach, Andrey L

    2013-04-01

    The chemistry, material processing and fundamental understanding of colloidal semiconductor nanocrystals (quantum dots) are advancing at an astounding rate, bringing the prospects of widespread commercialization of these novel and exciting materials ever closer. Interest in narrow bandgap nanocrystals in particular has intensified in recent years, and the results of research worldwide point to the realistic prospects of applications for these materials in solar cells, infrared optoelectronics (e.g. lasers, optical modulators, photodetectors and photoimaging devices), low cost/large format microelectronics, and in biological imaging and biosensor systems to name only some technologies. Improvements in fundamental understanding and material quality are built on a vast body of experience spread over many different methods of colloidal synthetic growth, each with their own strengths and weaknesses for different materials and sometimes with regard to particular applications. The nanocrystal growth expertise is matched by a rapidly expanding, and highly interdisciplinary, understanding of how best to assemble these materials into films or hybrid composites and thereby into useful devices, and again there are many different strategies that can be adopted. In this review we have attempted to survey and compare the recent work on colloidal synthesis, film and nanocrystal composite material fabrication, concentrating on narrow bandgap chalcogenide materials and some of their topical applications in the solar energy and biological fields. Since these applications are attracting rising interest across a wide range of disciplines, from the biological sciences, device engineering, and materials processing fields as well as the physics and synthetic chemistry communities, we have endeavoured to make the review of these narrow bandgap nanomaterials both comprehensive and accessible to newcomers to the area. PMID:23361653

  2. Nonlinear optical properties of colloidal silver nanoparticles produced by laser ablation in liquids

    SciTech Connect

    Karavanskii, V A; Krasovskii, V I; Ivanchenko, P V; Simakin, Aleksandr V

    2004-07-31

    The optical and nonlinear optical properties of colloidal solutions of silver obtained by laser ablation in water and ethanol are studied. It is shown that freshly prepared colloids experience a full or partial sedimentation by changing their nonlinear optical properties. Aqueous colloids undergo a partial sedimentation and their nonlinear optical absorption changes to nonlinear optical transmission. The obtained results are interpreted using the Drude model for metal particles taking the particle size into account and can be explained by the sedimentation of larger silver particles accompanied by the formation of a stable colloid containing silver nanoparticles with a tentatively silver oxide shell. The characteristic size of particles forming such a stable colloid is determined and its optical nonlinearity is estimated. (nonlinear optical phenomena)

  3. Effective removal of heavy metal by biochar colloids under different pyrolysis temperatures.

    PubMed

    Qian, Linbo; Zhang, Wenying; Yan, Jingchun; Han, Lu; Gao, Weiguo; Liu, Rongqin; Chen, Mengfang

    2016-04-01

    Biochar colloids' association with heavy metal needs be studied to precisely evaluate the effectiveness of biochar as sorbents. The structure of biochar colloids and their roles in heavy metal removal were investigated by Fourier-Transform Infrared Spectroscopy, X-ray Diffraction and batch adsorption experiments, respectively. Due to the numerous oxygen function groups and mineral matters contained in biochar colloids, the removal capacity of chromium (Cr) and cadmium (Cd) to biochar colloids was much greater than that of biochar residues. The highest adsorption capacities of Cr(III) and Cd(II) under initial pH 3.5 were obtained by RS400, which were mainly attributed to the presence of oxygen function groups and mineral matters simultaneously. The highest removal capacity of Cr(VI) was observed by RS300 due to the additional reduction by phenolic functional groups of RS300C. Therefore, the functions of biochar colloids for heavy metal removal should be considered. PMID:26859330

  4. Colloid cyst: a case report.

    PubMed

    Grasu, Beatrice L; Alberico, Anthony M

    2011-01-01

    Colloid cysts are a rare clinical finding with a unique clinical presentation: non-specific paroxysmal headaches. The current recommended treatment is microsurgery, which poses the greatest risk to the patient but allows complete removal of the cyst to prevent recurrence. A 41-year old man presented with a colloid cyst located in the foramen of Monro causing obstructive hydrocephalus. He had paroxysmal headaches and memory and personality changes. Transcortical transventricle microsurgery was performed to remove the entire cyst. A temporary shunt was placed to prevent post-operative hydrocephalus. Normal neurological function returned upon cyst removal. PMID:22034805

  5. Building devices from colloidal quantum dots.

    PubMed

    Kagan, Cherie R; Lifshitz, Efrat; Sargent, Edward H; Talapin, Dmitri V

    2016-08-26

    The continued growth of mobile and interactive computing requires devices manufactured with low-cost processes, compatible with large-area and flexible form factors, and with additional functionality. We review recent advances in the design of electronic and optoelectronic devices that use colloidal semiconductor quantum dots (QDs). The properties of materials assembled of QDs may be tailored not only by the atomic composition but also by the size, shape, and surface functionalization of the individual QDs and by the communication among these QDs. The chemical and physical properties of QD surfaces and the interfaces in QD devices are of particular importance, and these enable the solution-based fabrication of low-cost, large-area, flexible, and functional devices. We discuss challenges that must be addressed in the move to solution-processed functional optoelectronic nanomaterials. PMID:27563099

  6. Characteristics of Advanced Placement environmental science reading teacher participants and their perceptions of the reading as a professional development experience

    NASA Astrophysics Data System (ADS)

    Crawford, Freda M.

    Sixty percent of American high schools offer one or more Advanced Placement courses, and several thousand Advanced Placement teachers serve as Readers or graders of Advanced Placement exams each year. This study was conducted to determine the characteristics of teachers who choose to participate in Advanced Placement Environmental Science Readings and determine how these teachers view the Reading experience as a form of professional development. This study was conducted with teacher participants at the June 2004 Advanced Placement Environmental Science Reading. Sixty of the 114 teacher participants completed a survey regarding their education background, age, experience level, educational philosophy, involvement in professional development opportunities, perceptions of the professional benefits of the Reading, and the influence of the Reading experience on their pedagogical practices. Semi-structured interviews were then conducted with a subset of 18 teacher participants to determine their perceptions regarding the professional benefits of the Reading experience, its potential to serve as a professional development activity, and perceived changes in their pedagogical practices resulting from participation in the Reading process. Results indicate that APES Reading teacher participants are experienced, effective teachers from many parts of the country. These teachers participate in ongoing professional development activities, can delineate components of effective professional development, strongly believe that effective professional development occurs at the APES Reading, and report that their pedagogical practice has improved as a result of participation in the APES Reading. Considering the crucial role teachers play in the educational process, it is important to pursue this additional avenue of professional development in order to further improve APES teacher effectiveness.

  7. Synthesis and Characterization of Supramolecular Colloids.

    PubMed

    Vilanova, Neus; De Feijter, Isja; Voets, Ilja K

    2016-01-01

    Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer. PMID:27168201

  8. Colloid Mobilization and Porous Media Permeability Changes by Dynamic Stress Stimulations

    SciTech Connect

    Abdel-Fattah, Amr I.; Roberts, Peter M; Tarimala, Sowmitri; Ibrahim, Reem; Beckham, Richard

    2010-12-10

    Laboratory experiments on porous rock cores have shown that seismic-band (100 Hz or less) mechanical stress/strain cycling of the rock matrix can mobilize sub-pore-size particles (colloids) trapped in the pore space and allow them to be expelled during steady-state water flow. This coupling of dynamic stress to colloid mobility is a potential key mechanism whereby seismic waves may alter formation permeability and porous mass transport in Earth's crust. Experiments where colloid suspensions were injected into Fontainebleau sandstone cores demonstrated that colloid size and the ionic strength of the suspending fluid are major parameters that will control the ability of the colloids to attach to pore walls or to form particle bridges at pore throats. Both effects can lead to significant changes in permeability. A unique core-holder apparatus that applies low-frequency mechanical stress/strain to 2.54-cm-diameter porous rock samples during constant-rate fluid flow was used for those experiments. Microsphere injection caused the core's permeability to decline due to colloid bridging at pore throats. It was found that dynamic stress at 25 to 50 Hz mobilized these trapped colloids mainly when the ionic strength is low, and thereby partially restored the permeability of the sample. These earlier experiments on natural rocks were difficult to interpret in terms of how the colloids distributed themselves throughout the heterogeneous pore space and what interactions were occurring between the colloids and the solid matrix. Observed permeability changes appeared to be confined to the first 5-10 cm of the rock where the colloids were injected, yet significant transport of colloids was observed along the entire length of the sample. The 'natural rock' system is too complex geometrically at the pore scale to allow quantification of mass transport properties along its entire length. To remedy this problem, new colloid transport experiments were performed with a synthetic glass

  9. Development, Evaluation and Use of a Student Experience Survey in Undergraduate Science Laboratories: The Advancing Science by Enhancing Learning in the Laboratory Student Laboratory Learning Experience Survey

    NASA Astrophysics Data System (ADS)

    Barrie, Simon C.; Bucat, Robert B.; Buntine, Mark A.; Burke da Silva, Karen; Crisp, Geoffrey T.; George, Adrian V.; Jamie, Ian M.; Kable, Scott H.; Lim, Kieran F.; Pyke, Simon M.; Read, Justin R.; Sharma, Manjula D.; Yeung, Alexandra

    2015-07-01

    Student experience surveys have become increasingly popular to probe various aspects of processes and outcomes in higher education, such as measuring student perceptions of the learning environment and identifying aspects that could be improved. This paper reports on a particular survey for evaluating individual experiments that has been developed over some 15 years as part of a large national Australian study pertaining to the area of undergraduate laboratories-Advancing Science by Enhancing Learning in the Laboratory. This paper reports on the development of the survey instrument and the evaluation of the survey using student responses to experiments from different institutions in Australia, New Zealand and the USA. A total of 3153 student responses have been analysed using factor analysis. Three factors, motivation, assessment and resources, have been identified as contributing to improved student attitudes to laboratory activities. A central focus of the survey is to provide feedback to practitioners to iteratively improve experiments. Implications for practitioners and researchers are also discussed.

  10. Impact of Dissolved Organic Matter on Colloid Transport in the Vadose Zone

    NASA Astrophysics Data System (ADS)

    Morales, V. L.; Gao, B.; Steenhuis, T. S.

    2008-05-01

    Mobile soil colloids can facilitate contaminant transport through the soil profile through complexation of pollutants previously thought to have very limited mobility in soil. Much work has been done to define the governing transport mechanisms of colloids in unsaturated media, and have demonstrated that the release, transport, and retention of colloidal particles in soil are very sensitive to flow chemistry. However, better understanding of the physicochemical interactions between dissolved organic matter (DOM) and soil colloids is clearly needed, as the transport in manure rich soils has been observed to be much greater than originally suspected. The goal of this study is to fill this knowledge gap by elucidating the role of DOM on the transport and retention of colloidal particles in the vadose zone through multi-scale investigations. The initial phase of the experimental work consists of collecting concomitant visual (with Bright Field Microscopy and Confocal Laser Scanning Microscopy) and breakthrough data from medium sized (d50 = 0.4 mm) quartz sand filled chambers of 10x2x2 cm and 1 cm diameter x 10 cm length. Pulses of synthetic and clay colloid suspensions will be individually injected into the flow chambers at various concentrations of DOM (i.e. extracted humic acid from manure). Results from these experiments indicate that DOM can increase colloid stability in water and thereby potentially facilitate the transport of contaminants adsorbed onto suspended and mobile colloids.

  11. Strong collective attraction in colloidal clusters on a liquid-air interface.

    PubMed

    Pergamenshchik, V M

    2009-01-01

    It is shown that in a cluster of many colloids, trapped at a liquid-air interface, the well-known vertical-force-induced pairwise logarithmic attraction changes to a strongly enhanced power-law attraction. In large two-dimensional clusters, the attraction energy scales as the inverse square of the distance between colloids. The enhancement is given by the ratio eta = (square of the capillary length) / (interface surface area per colloid) and can be as large as 10;{5} . This explains why a very small vertical force on colloids, which is too weak to bring two of them together, can stabilize many-body structures on a liquid-air interface. The profile of a cluster is shown to consist of a large slow collective envelope modulated by a fast low-amplitude perturbation due to individual colloids. A closed equation for the slow envelope, which incorporates an arbitrary power-law repulsion between colloids, is derived. For example, this equation is solved for a large circular cluster with the hard-core colloid repulsion. It is suggested that the predicted effect is responsible for mysterious stabilization of colloidal structures observed in experiments on a surface of isotropic liquid and nematic liquid crystal. PMID:19257035

  12. Non-equilibrium colloidal assembly pathways via synergistic dipolar, depletion, and hydrodynamic interactions

    NASA Astrophysics Data System (ADS)

    Coughlan, Anna; Bevan, Michael

    The ability to assemble nano- and micro- colloidal particles into ordered materials and controllable devices provides the basis for emerging technologies. However, current capabilities for manipulating colloidal assembly are limited by the degree of order, time to generate/reconfigure structures, and scalability to large areas. These limitations are due to problems with designing, controlling, and optimizing the thermodynamics and kinetics of colloidal assembly. Our approach is to provide viable non-equilibrium pathways for rapid assembly of defect free colloidal crystals using combinations of magnetic field and depletion mediated assembly. Results include video microscopy experiments and Stokesian Dynamic computer simulations of superparamagnetic colloidal particles experiencing depletion attraction in time varying magnetic fields. Findings show multi-body hydrodynamic interactions and magnetic dipole relaxation mechanisms are essential to capture assembly and annealing of attractive colloidal crystals. With the ability to measure, model and tune colloidal interactions and dynamics, we demonstrate the use of time varying fields to manipulate non-equilibrium pathways for the assembly, disassembly, and repair of colloidal microstructures.

  13. Periodically microstructured composite films made by electric- and magnetic-directed colloidal assembly.

    PubMed

    Demirörs, Ahmet Faik; Courty, Diana; Libanori, Rafael; Studart, André R

    2016-04-26

    Living organisms often combine soft and hard anisotropic building blocks to fabricate composite materials with complex microstructures and outstanding mechanical properties. An optimum design and assembly of the anisotropic components reinforces the material in specific directions and sites to best accommodate multidirectional external loads. Here, we fabricate composite films with periodic modulation of the soft-hard microstructure by simultaneously using electric and magnetic fields. We exploit forefront directed-assembly approaches to realize highly demanded material microstructural designs and showcase a unique example of how one can bridge colloidal sciences and composite technology to fabricate next-generation advanced structural materials. In the proof-of-concept experiments, electric fields are used to dictate the position of the anisotropic particles through dielectrophoresis, whereas a rotating magnetic field is used to control the orientation of the particles. By using such unprecedented control over the colloidal assembly process, we managed to fabricate ordered composite microstructures with up to 2.3-fold enhancement in wear resistance and unusual site-specific hardness that can be locally modulated by a factor of up to 2.5. PMID:27071113

  14. Pultonium Colloid-Facilitated Transport in the Environment - Experimental and Transport Modeling Evidence for Plutonium Migration Mechanisms

    SciTech Connect

    Zavarin, M; Maxwell, R M; Kersting, A B; Zhao, P; Sylwester, E R; Allen, P G; Williams, R W

    2003-02-19

    Natural inorganic colloids (< 1 micron particles) found in groundwater can sorb low-solubility actinides and may provide a pathway for transport in the subsurface. For example, Kerting et al found that Pu, associated with colloids fraction of the groundwater, was detected over 1 km away from the underground nuclear test at the Nevada Test Site (NTS) where it was originally deposited 28 years earlier. However, laboratory experiments have not identified the mechanisms by which Pu may sorb to colloids or exist as its own colloid and travel relatively unimpeded in the subsurface. Some data suggest that Pu sorption to colloids is a very fast process while desorption is very slow or simply does not occur. Slow desorption of Pu from colloids could allow Pu sorbed to a colloid to travel much farther than if sorption were an equilibrium process. However, PU sorption (and particularly desorption) data in the literature are scant and sometimes contradictory. In some cases, Pu desorption is rather fast, with rates dependent on colloid mineralogy. Moreover, the effect of sorption and desorption kinetics (as well as other mechanisms) on colloid-facilitated transport at the field scale has not been thoroughly evaluated. This is, in part, due to limitations in colloid transport as well as sorption/desorption models.

  15. Heat-Resistant Crack-Free Superhydrophobic Polydivinylbenzene Colloidal Films.

    PubMed

    Wang, Zefeng; Ye, Weiwei; Luo, Xinran; Wang, Zhonggang

    2016-03-29

    Highly cross-linked poly(divinylbenzene) (PDVB) spherical colloidal particles with nano-, submicron-, and micron-sizes of 157.2 nm, 602.1 nm, and 5.1 μm were synthesized through emulsion and dispersion polymerization methods. The influences of particle size on the surface morphology, roughness, superhydrophobicity, and critical cracking thickness of colloidal films were studied in detail. The results show that PDVB colloidal films possess large water contact angle (CA) over 151°, belonging to superhydrophobic materials. Moreover, it is interesting to observe that the highly cross-linked network structure leads to PDVB film's excellent heat-resistance. The CA and rough surface morphology remain nearly unchanged after thermal-treatment of films at 150 °C for 24 h. In addition, no cracks were observed in films with thicknesses up to 8.1 μm, exceeding most of polymer and inorganic particle films reported in the literature. The simple and scalable preparation method, low-cost, superhydrophobicity, and excellent thermal stability endow the PDVB colloidal films with promising applications in advanced coating fields, especially when employed in the high-temperature service environment. PMID:26986041

  16. Chemistry of the colloidal group II-VI nanocrystal synthesis

    NASA Astrophysics Data System (ADS)

    Liu, Haitao

    In the last two decades, the field of nanoscience and nanotechnology has witnessed tremendous advancement in the synthesis and application of group II-VI colloidal nanocrystals. The synthesis based on high temperature decomposition of organometallic precursors has become one of the most successful methods of making group II-VI colloidal nanocrystals. This method is first demonstrated by Bawendi and coworkers in 1993 to prepare cadmium chalcogenide colloidal quantum dots and later extended by others to prepare other group II-VI quantum dots as well as anisotropic shaped colloidal nanocrystals, such as nanorod and tetrapod. This dissertation focuses on the chemistry of this type of nanocrystal synthesis. The synthesis of group II-VI nanocrystals was studied by characterizing the molecular structures of the precursors and products and following their time evolution in the synthesis. Based on these results, a mechanism was proposed to account for the reaction between the precursors that presumably produces monomer for the growth of nanocrystals. Theoretical study based on density functional theory calculations revealed the detailed free energy landscape of the precursor decomposition and monomer formation pathway. Based on the proposed reaction mechanism, a new synthetic method was designed that uses water as a novel reagent to control the diameter and the aspect ratio of CdSe and US nanorods.

  17. Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

  18. Acoustic Stimulation of Colloid Behavior at the Pore and Core Scales

    NASA Astrophysics Data System (ADS)

    Roberts, P. M.

    2006-12-01

    Acoustic waves can influence the attachment and/or detachment of colloids at solid/liquid interfaces. They can also induce colloid-colloid interactions leading to colloid trapping or clustering. Subsequent accumulation or release of colloids in a porous medium can alter its permeability. This can cause either good or bad effects on porous fluid-flow behavior in the Earth and geomaterials. Prior experiments using a microscopic, video image- processing system focused on a glass flow-visualization cell indicated that 0.5 to 5 MHz acoustic energy can induce attachment and detachment of sub-micron-size polystyrene microspheres at solid/liquid interfaces. New experiments were performed to investigate the effect of particle size, concentration (volume fraction), ionic strength, and acoustic energy on the deposition and removal kinetics of colloidal particles onto different solid surfaces. Additional experiments demonstrated that acoustically excited particles can attract other particles and cause them to orbit each other in directions that depend on the acoustic frequency. Other prior experiments on centimeter-size sandstone cores showed that 50 Hz mechanical stress oscillations can mobilize trapped in-situ colloids as well as injected 300-nm polystyrene microspheres. A unique core-holder apparatus that mechanically strains 2.54-cm-diameter porous rock samples during constant-rate fluid flow was used for those experiments. To investigate the effect of particle size on trapping and acoustic release of colloids, new experiments were performed by injecting 1-micron microspheres suspended in deionized water and 0.1M NaCl solution. The larger size microspheres were trapped at both high and low ionic strengths, unlike the smaller 300-nm microspheres which were only trapped at high ionic strength. Stress stimulation at less than 100 Hz caused enhanced release of the trapped microspheres at a rate much higher than the average background production rate during water flow alone

  19. Colloid characterization and quantification in groundwater samples

    SciTech Connect

    K. Stephen Kung

    2000-06-01

    This report describes the work conducted at Los Alamos National Laboratory for studying the groundwater colloids for the Yucca Mountain Project in conjunction with the Hydrologic Resources Management Program (HRMP) and the Underground Test Area (UGTA) Project. Colloidal particle size distributions and total particle concentration in groundwater samples are quantified and characterized. Colloid materials from cavity waters collected near underground nuclear explosion sites by HRMP field sampling personnel at the Nevada Test Site (NTS) were quantified. Selected colloid samples were further characterized by electron microscope to evaluate the colloid shapes, elemental compositions, and mineral phases. The authors have evaluated the colloid size and concentration in the natural groundwater sample that was collected from the ER-20-5 well and stored in a 50-gallon (about 200-liter) barrel for several months. This groundwater sample was studied because HRMP personnel have identified trace levels of radionuclides in the water sample. Colloid results show that even though the water sample had filtered through a series of Millipore filters, high-colloid concentrations were identified in all unfiltered and filtered samples. They had studied the samples that were diluted with distilled water and found that diluted samples contained more colloids than the undiluted ones. These results imply that colloids are probably not stable during the storage conditions. Furthermore, results demonstrate that undesired colloids have been introduced into the samples during the storage, filtration, and dilution processes. They have evaluated possible sources of colloid contamination associated with sample collection, filtrating, storage, and analyses of natural groundwaters. The effects of container types and sample storage time on colloid size distribution and total concentration were studied to evaluate colloid stability by using J13 groundwater. The data suggests that groundwater samples

  20. Recent experience with multidisciplinary analysis and optimization in advanced aircraft design

    NASA Technical Reports Server (NTRS)

    Dollyhigh, Samuel M.; Sobieszczanski-Sobieski, Jaroslaw

    1990-01-01

    The task of modern aircraft design has always been complicated due to the number of intertwined technical factors from the various engineering disciplines. Furthermore, this complexity has been rapidly increasing by the development of such technologies as aeroelasticity tailored materials and structures, active control systems, integrated propulsion/airframe controls, thrust vectoring, and so on. Successful designs that achieve maximum advantage from these new technologies require a thorough understanding of the physical phenomena and the interactions among these phenomena. A study commissioned by the Aeronautical Sciences and Evaluation Board of the National Research Council has gone so far as to identify technology integration as a new discipline from which many future aeronautical advancements will arise. Regardless of whether one considers integration as a new discipline or not, it is clear to all engineers involved in aircraft design and analysis that better methods are required. In the past, designers conducted parametric studies in which a relatively small number of principal characteristics were varied to determine the effect on design requirements which were themselves often diverse and contradictory. Once a design was chosen, it then passed through the various engineers' disciplines whose principal task was to make the chosen design workable. Working in a limited design space, the discipline expert sometimes improved the concept, but more often than not, the result was in the form of a penalty to make the original concept workable. If an insurmountable problem was encountered, the process began over. Most design systems that attempt to account for disciplinary interactions have large empirical elements and reliance on past experience is a poor guide in obtaining maximum utilizations of new technologies. Further compounding the difficulty of design is that as the aeronautical sciences have matured, the discipline specialist's area of research has generally

  1. Rheology, microstructure and migration in brownian colloidal suspensions.

    PubMed

    Pan, Wenxiao; Caswell, Bruce; Karniadakis, George Em

    2010-01-01

    We demonstrate that suspended spherical colloidal particles can be effectively modeled as single dissipative particle dynamics (DPD) particles provided that the conservative repulsive force is appropriately chosen. The suspension model is further improved with a new formulation, which augments standard DPD with noncentral dissipative shear forces between particles while preserving angular momentum. Using the new DPD formulation we investigate the rheology, microstructure and shear-induced migration of a monodisperse suspension of colloidal particles in plane shear flows (Couette and Poiseuille). Specifically, to achieve a well-dispersed suspension we employ exponential conservative forces for the colloid-colloid and colloid-solvent interactions but keep the conventional linear force for the solvent-solvent interactions. Our simulations yield relative viscosity versus volume fraction predictions in good agreement with both experimental data and empirical correlations. We also compute the shear-dependent viscosity and the first and second normal-stress differences and coefficients in both Couette and Poiseuille flow. Simulations near the close packingvolume-fraction (64%) at low shear rates demonstrate a transition to flow-induced string-like structures of colloidal particles simultaneously with a transition to a nonlinear Couette velocity profile in agreement with experimental observations. After a sufficient increase ofthe shear rate the ordered structure melts into disorder with restoration of the linear velocity profile. Migration effects simulated in Poiseuille flow compare well with experiments and model predictions. The important role of angular momentum and torque in nondilute suspensions is also demonstrated when compared with simulations by the standard DPD, which omits the angular degrees of freedom. Overall, the new method agrees very well with the Stokesian Dynamics method but it seems to have lower computational complexity and is applicable to general

  2. Solid colloidal optical wavelength filter

    DOEpatents

    Alvarez, Joseph L.

    1992-01-01

    A solid colloidal optical wavelength filter includes a suspension of spheal particles dispersed in a coagulable medium such as a setting plastic. The filter is formed by suspending spherical particles in a coagulable medium; agitating the particles and coagulable medium to produce an emulsion of particles suspended in the coagulable medium; and allowing the coagulable medium and suspended emulsion of particles to cool.

  3. Sonochemical synthesis of iron colloids

    SciTech Connect

    Suslick, K.S.; Fang, M.; Hyeon, T.

    1996-11-27

    We present here a new method for the preparation of stable ferromagnetic colloids of iron using high-intensity ultrasound to sonochemically decompose volatile organometallic compounds. These colloids have narrow size distributions centered at a few nanometers and are found to be superparamagnetic. In conclusion, a simple synthetic method has been discovered to produce nanosized iron colloid using high-intensity ultrasound. Nanometer iron particles dispersed in polyvinylpyrrolidone (PVP) matrix or stabilized by adsorption of oleic acid have been synthesized by sonochemical decomposition of Fe(CO){sub 5}. Transmission electron micrographs show that the iron particles have a relatively narrow range in size from 3 to 8 nm for polyvinylpyrrolidone, while oleic acid gives an even more uniform distribution at 8 nm. magnetic measurements revealed that these nanometer iron particles are superparamagnetic with a saturation magnetization of 101 emu/g (Fe) at 290 K. This work is easily extended to colloids of other metals and to alloys of two or more metals, simply by using multiple volatile precursors. 29 refs., 4 figs.

  4. Physics of Colloids in Space

    NASA Technical Reports Server (NTRS)

    Weitz, Dave; Weeks, Eric; Gasser, Urs; Dinsmore, Tony; Mawley, Suliana; Segre, Phil; Cipelletti, Lucia

    2000-01-01

    This talk will present recent results from ground-based research to support the "Physics of Colloids in Space" project which is scheduled to fly in the ISS approximately one year from now. In addition, results supporting future planned flights will be discussed.

  5. Dynamics of evaporative colloidal patterning

    NASA Astrophysics Data System (ADS)

    Kaplan, C. Nadir; Wu, Ning; Mandre, Shreyas; Aizenberg, Joanna; Mahadevan, L.

    2015-09-01

    Drying suspensions often leave behind complex patterns of particulates, as might be seen in the coffee stains on a table. Here, we consider the dynamics of periodic band or uniform solid film formation on a vertical plate suspended partially in a drying colloidal solution. Direct observations allow us to visualize the dynamics of band and film deposition, where both are made of multiple layers of close packed particles. We further see that there is a transition between banding and filming when the colloidal concentration is varied. A minimal theory of the liquid meniscus motion along the plate reveals the dynamics of the banding and its transition to the filming as a function of the ratio of deposition and evaporation rates. We also provide a complementary multiphase model of colloids dissolved in the liquid, which couples the inhomogeneous evaporation at the evolving meniscus to the fluid and particulate flows and the transition from a dilute suspension to a porous plug. This allows us to determine the concentration dependence of the bandwidth and the deposition rate. Together, our findings allow for the control of drying-induced patterning as a function of the colloidal concentration and evaporation rate.

  6. Colloid facilitated transport in fractured rocks : parameter estimation and comparison with experimental data.

    SciTech Connect

    Viswanathan, H. S.; Wolfsberg, A. V.; Reimus, P. W.; Ware, S. D.; Lu, G.

    2003-01-01

    Colloid-facilitated migration of plutonium in fractured rock has been implicated in both field and laboratory studies . Other reactive radionuclides may also experience enhanced mobility due to groundwater colloids. Model prediction of this process is necessary for assessment of contaminant boundaries in systems for which radionuclides are already in the groundwater and for performance assessment of potential repositories for radioactive waste. Therefore, a reactive transport model is developed and parameterized using results from controlled laboratory fracture column experiments. Silica, montmorillonite and clinoptilolite colloids are used in the experiments along with plutonium and Tritium . . The goal of the numerical model is to identify and parameterize the physical and chemical processes that affect the colloid-facilitated transport of plutonium in the fractures. The parameters used in this model are similar in form to those that might be used in a field-scale transport model.

  7. Colloid facilitated transport in fractured rocks: parameter estimation and comparison with experimental data

    SciTech Connect

    Viswanthan, H.S.; Wolfsberg, A.V.; Reimus, P.W.; Ware, D.; Lu, G.

    2003-01-10

    Colloid-facilitated migration of plutonium in fractured rock has been implicated in both field and laboratory studies. Other reactive radionuclides may also experience enhanced mobility due to groundwater colloids. Model prediction of this process is necessary for assessment of contaminant boundaries in systems for which radionuclides are already in the groundwater and for performance assessment of potential repositories for radioactive waste. Therefore, a reactive transport model is developed and parameterized using results from controlled laboratory fracture column experiments. Silica, montmorillonite and clinoptilolite colloids are used in the experiments along with plutonium and Tritium. The goal of the numerical model is to identify and parameterize the physical and chemical processes that affect the colloid-facilitated transport of plutonium in the fractures. The parameters used in this model are similar in form to those that might be used in a field-scale transport model.

  8. Polydispersity and gelation in concentrated colloids with competing interactions.

    PubMed

    Zhang, Tian Hui; Kuipers, Bonny W M; Tian, Wen-de; Groenewold, Jan; Kegel, Willem K

    2015-01-14

    In colloids with competing short-range attractions and long-range repulsions, microcrystalline gels are experimentally formed under conditions where computer simulations point to a lamellar phase as the ground state. Here, upon applying a low-frequency alternating electric field, we bring the system from an initial gel state to a columnar-like state. While molecular dynamics simulations on monodisperse colloids reveal that a columnar structure spontaneously evolves towards a lamellar phase, the columnar-like state in experiments relaxes back to the initial disordered gel state once the electric field is switched off. Similarly, a columnar phase in molecular dynamics simulations decomposes into finite-size crystalline clusters as the relative polydispersity of the colloids is around 1.0%. We conclude that the experimentally observed melting of the columnar structure is driven by polydispersity. Moreover, further simulations reveal that the critical polydispersity required to destabilize a long-range ordered structure increases with the attraction range, pointing to the possibility of observing periodic structures in experiments if the attraction range is sufficiently long compared to the polydispersity of the colloids. PMID:25407503

  9. Colloid-Facilitated Transport of Cations in an Unsaturated Fractured Soil Under Transient Conditions

    SciTech Connect

    Ryan, Joseph

    2015-01-31

    Rainfall experiments were conducted using intact soil cores and an instrumented soil pedon to examine the effect of physical heterogeneity and rainfall characteristics on the mobilization of colloids, organic matter, cesium, and strontium in a fractured soil. To measure the spatial variability of infiltration of colloids and contaminants, samples were collected through a 19-port grid placed below the soil core in laboratory study and in 27 samplers at multiple depths in the soil pedon in the field study. Cesium and strontium were applied to the soil cores and the soil pedon prior to mobilization experiments. Rainwater solutions of multiple ionic strengths and organic matter concentrations were applied to the soil cores and soil pedon to mobilize in situ colloids, cesium, and strontium. The mobilization of colloids and metal cations occurred through preferential flow paths in the soil cores. Compared to steady rainfall, greater amounts of colloids were mobilized during rainfall interrupted by pauses, which indicates that the supply of colloids to be mobilized was replenished during the pauses. A maximum in the amount of mobilized colloids were mobilized during a rainfall following a pause of 2.5 d. Pauses of shorter or longer duration resulted in less colloid mobilization. Freeze-thaw cycles, a transient condition in winter, enhanced colloid mobilization and colloid-facilitated transport of cesium and strontium in the soil cores. The exchange of solutes between the soil matrix and macropores caused a hysteretic mobilization of colloids, cesium, and strontium during changes in ionic strength. Colloid-facilitated mobilization of cesium and strontium was important at low ionic strength in fractures where slow flow allowed greater exchange of flow between the fractures and the surrounding matrix. The release of cesium and strontium by cation exchange occurred at high ionic strength in fractures where there is a little exchange of pore water with the surrounding matrix

  10. Colloid-Facilitated Transport of Low-Solubility Radionuclides: A Field, Experimental, and Modeling Investigation

    SciTech Connect

    Kersting, A B; Reimus, P W; Abdel-Fattah, A; Allen, P G; Anghel, I; Benedict, F C; Esser, B K; Lu, N; Kung, K S; Nelson, J; Neu, M P; Reilly, S D; Smith, D K; Sylwester, E R; Wang, L; Ware, S D; Warren, RG; Williams, R W; Zavarin, M; Zhao, P

    2003-02-01

    rate of Pu transport. Currently, the role of colloids in facilitating the transport of low-solubility radionuclides is not understood well enough to effectively model contaminant transport. A fundamental understanding of the role that colloids may or may not play in the transport of low-solubility radionuclides is needed in order to predict contaminant transport, design remediation strategies and provide risk assessments. Ryan and Elimelech (1996) have argued that in order to evaluate the potential for colloids to transport radionuclides, several criteria must be met: (1) colloids must exist and be stable, (2) radionuclides must have a high sorption affinity for the colloids, and (3) colloids must be transported. Only then can we understand the conditions where colloids can and will facilitate transport of radionuclides. In this report we compile the results from a series of field, laboratory and modeling studies funded by the UGTA program in order to evaluate the potential for colloids to transport low-solubility radionuclides at the NTS. The studies presented in this report fall under three general areas of investigation: Characterization of natural colloids in groundwater at NTS, Pu sorption/desorption experiments on colloid minerals identified in NTS groundwater, and Transport of Pu-doped colloids through fractured rock core. Chapter 1 is a background review of our current understanding of colloids and their role in facilitating contaminant transport. Chapters 2, and 3 are field studies that focused on characterizing natural colloids at different hydrologic environments at the NTS and address Ryan and Elimelech's (1996) first criteria regarding the existence and stability of colloids. Chapters 4, 5 and 6 are laboratory experimental studies that investigate the sorption/desorption behavior of Pu and other low-solubility radionuclides on colloid minerals observed in NTS groundwater. These studies evaluate Ryan and Elimelech's (1996) second criteria that the affinity

  11. Glassy dislocation dynamics in colloidal dimer crystals

    NASA Astrophysics Data System (ADS)

    Gerbode, Sharon

    2012-02-01

    Dislocation mobility is central to both the mechanical response and the relaxation mechanisms of crystalline materials. Recent experiments have explored the role of novel particle anisotropies in affecting the rules of defect motion in crystals. ``Peanut-shaped'' colloidal dimer particles consisting of two connected spherical lobes form densely packed crystals in 2D. In these ``degenerate crystals,'' the particle lobes occupy triangular lattice sites while the particle axes are randomly oriented among the three crystalline directions. One consequence of the random orientations of the dimers is that dislocation glide is severely limited by certain particle arrangements in the degenerate crystals. Using optical tweezers to manipulate single lobe-sized spherical intruder particles, we locally deform the crystal, creating defects. During subsequent relaxation, the dislocations formed during the deformation leave the crystal grain, either via annihilation with other dislocations or by moving to a grain boundary. Interestingly, in large crystalline grains this dislocation relaxation occurs through a two-stage process reminiscent of slow relaxations in glassy systems, suggesting the novel concept that glassy phenomena may be introduced to certain kinds of colloidal crystals via simple anisotropic constituents.

  12. Removal of colloidal biogenic selenium from wastewater.

    PubMed

    Staicu, Lucian C; van Hullebusch, Eric D; Oturan, Mehmet A; Ackerson, Christopher J; Lens, Piet N L

    2015-04-01

    Biogenic selenium, Se(0), has colloidal properties and thus poses solid-liquid separation problems, such as poor settling and membrane fouling. The separation of Se(0) from the bulk liquid was assessed by centrifugation, filtration, and coagulation-flocculation. Se(0) particles produced by an anaerobic granular sludge are normally distributed, ranging from 50 nm to 250 nm, with an average size of 166±29 nm and a polydispersity index of 0.18. Due to its nanosize range and protein coating-associated negative zeta potential (-15 mV to -23 mV) between pH 2 and 12, biogenic Se(0) exhibits colloidal properties, hampering its removal from suspension. Centrifugation at different centrifugal speeds achieved 22±3% (1500 rpm), 73±2% (3000 rpm) and 91±2% (4500 rpm) removal. Separation by filtration through 0.45 μm filters resulted in 87±1% Se(0) removal. Ferric chloride and aluminum sulfate were used as coagulants in coagulation-flocculation experiments. Aluminum sulfate achieved the highest turbidity removal (92±2%) at a dose of 10(-3) M, whereas ferric chloride achieved a maximum turbidity removal efficiency of only 43±4% at 2.7×10(-4) M. Charge repression plays a minor role in particle neutralization. The sediment volume resulting from Al2(SO3)4 treatment is three times larger than that produced by FeCl3. PMID:25559175

  13. Colloidal aggregation and dynamics in anisotropic fluids

    PubMed Central

    Mondiot, Frédéric; Botet, Robert; Snabre, Patrick; Mondain-Monval, Olivier; Loudet, Jean-Christophe

    2014-01-01

    We present experiments and numerical simulations to investigate the collective behavior of submicrometer-sized particles immersed in a nematic micellar solution. We use latex spheres with diameters ranging from 190 to 780 nm and study their aggregation properties due to the interplay of the various colloidal forces at work in the system. We found that the morphology of aggregates strongly depends on the particle size, with evidence for two distinct regimes: the biggest inclusions clump together within minutes into either compact clusters or V-like structures that are completely consistent with attractive elastic interactions. On the contrary, the smallest particles form chains elongated along the nematic axis, within comparable timescales. In this regime, Monte Carlo simulations, based on a modified diffusion-limited cluster aggregation model, strongly suggest that the anisotropic rotational Brownian motion of the clusters combined with short-range depletion interactions dominate the system coarsening; elastic interactions no longer prevail. The simulations reproduce the sharp transition between the two regimes on increasing the particle size. We provide reasonable estimates to interpret our data and propose a likely scenario for colloidal aggregation. These results emphasize the growing importance of the diffusion of species at suboptical-wavelength scales and raise a number of fundamental issues. PMID:24715727

  14. Phase transformations in binary colloidal monolayers.

    PubMed

    Yang, Ye; Fu, Lin; Marcoux, Catherine; Socolar, Joshua E S; Charbonneau, Patrick; Yellen, Benjamin B

    2015-03-28

    Phase transformations can be difficult to characterize at the microscopic level due to the inability to directly observe individual atomic motions. Model colloidal systems, by contrast, permit the direct observation of individual particle dynamics and of collective rearrangements, which allows for real-space characterization of phase transitions. Here, we study a quasi-two-dimensional, binary colloidal alloy that exhibits liquid-solid and solid-solid phase transitions, focusing on the kinetics of a diffusionless transformation between two crystal phases. Experiments are conducted on a monolayer of magnetic and nonmagnetic spheres suspended in a thin layer of ferrofluid and exposed to a tunable magnetic field. A theoretical model of hard spheres with point dipoles at their centers is used to guide the choice of experimental parameters and characterize the underlying materials physics. When the applied field is normal to the fluid layer, a checkerboard crystal forms; when the angle between the field and the normal is sufficiently large, a striped crystal assembles. As the field is slowly tilted away from the normal, we find that the transformation pathway between the two phases depends strongly on crystal orientation, field strength, and degree of confinement of the monolayer. In some cases, the pathway occurs by smooth magnetostrictive shear, while in others it involves the sudden formation of martensitic plates. PMID:25677504

  15. The effect of the low Earth orbit environment on space solar cells: Results of the Advanced Photovoltaic Experiment (S0014)

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.; Scheiman, David A.

    1993-01-01

    The results of post-flight performance testing of the solar cells flown on the Advanced Photovoltaic Experiment are reported. Comparison of post-flight current-voltage characteristics with similar pre-flight data revealed little or no change in solar cell conversion efficiency, confirming the reliability and endurance of space photovoltaic cells. This finding is in agreement with the lack of significant physical changes in the solar cells despite nearly six years in the low Earth orbit environment.

  16. Distorted colloidal arrays as designed template

    NASA Astrophysics Data System (ADS)

    Yu, Ye; Zhou, Ziwei; Möhwald, Helmuth; Ai, Bin; Zhao, Zhiyuan; Ye, Shunsheng; Zhang, Gang

    2015-01-01

    In this paper, a novel type of colloidal template with broken symmetry was generated using commercial, inductively coupled plasma reactive ion etching (ICP-RIE). With proper but simple treatment, the traditional symmetric non-close-packed colloidal template evolves into an elliptical profile with high uniformity. This unique feature can add flexibility to colloidal lithography and/or other lithography techniques using colloidal particles as building blocks to fabricate nano-/micro-structures with broken symmetry. Beyond that the novel colloidal template we developed possesses on-site tunability, i.e. the transformability from a symmetric into an asymmetric template. Sandwich-type particles with eccentric features were fabricated utilizing this tunable template. This distinguishing feature will provide the possibility to fabricate structures with unique asymmetric features using one set of colloidal template, providing flexibility and broad tunability to enable nano-/micro-structure fabrication with colloidal templates.

  17. Glass/Jamming Transition in Colloidal Aggregation

    NASA Technical Reports Server (NTRS)

    Segre, Philip N.; Prasad, Vikram; Weitz, David A.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    We have studied colloidal aggregation in a model colloid plus polymer system with short-range attractive interactions. By varying the colloid concentration and the strength of the attraction, we explored regions where the equilibrium phase is expected to consist of colloidal crystallites in coexistance with colloidal gas (i.e. monomers). This occurs for moderate values of the potential depth, U approximately equal to 2-5 kT. Crystallization was not always observed. Rather, over an extended sub-region two new metastable phases appear, one fluid-like and one solid-like. These were examined in detail with light scattering and microscopy techniques. Both phases consist of a near uniform distribution of small irregular shaped clusters of colloidal particles. The dynamical and structural characteristics of the ergodic-nonergodic transition between the two phases share much in common with the colloidal hard sphere glass transition.

  18. Simultaneous transport of synthetic colloids and a nonsorbing solute through single saturated natural fractures

    SciTech Connect

    Reimus, P.W.; Robinson, B.A.; Nuttall, H.E.; Kale, R.

    1994-09-01

    Tracer transport experiments involving colloids that showed little tendency to attach to rock surfaces and a nonsorbing solute (iodide) -were conducted in three different well-characterized natural fractures in tuff. The colloids always arrived earlier in the effluent than the iodide, which we believe is evidence of (1) hydrodynamic chromatography and/or (2) the fact that the colloids experience a smaller effective volume in the fracture because they diffuse too slowly to enter low-velocity regions (dead zones) along the rough fracture walls. The iodide also approached the inlet concentration in the effluent more slowly than the colloids, with the concentration at a given elution volume being greater at higher flow rates. By contrast, the rate of approach of the colloid concentration to the inlet concentration did not vary with flow rate. We attribute this behavior to matrix diffusion of the iodide, with the colloids being too large/nondiffusive to experience this phenomenon. Dispersion of all tracers was greatest in the fracture of widest average aperture and least in the fracture of narrowest aperture, which is consistent with Taylor dispersion theory. The tracer experiments were modeled/interpreted using a three-step approach that involved (1) estimating the aperture distribution in each fracture using surface profiling techniques, (2) predicting the flow field in the fractures using a localized parallel-plate approximation, and (3) predicting tracer transport in the fractures using particle-tracking techniques. Although considered preliminary at this time, the model results were in qualitative agreement with the experiments.

  19. Project Description Advanced Fuel Cycle Initiative AFC-2A and AFC-2B Experiments

    SciTech Connect

    AFCI AFC-2A and AFC-2B Experiments Project Executi

    2007-03-01

    The proposed AFC-2A and AFC-2B irradiation experiments are a continuation of the AFC-1 fuel test series currently in progress in the ATR. This document discusses the experiments and the planned activities that will take place.

  20. Mesoscopic dynamics of colloids simulated with dissipative particle dynamics and fluid particle model.

    PubMed

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

    2002-01-01

    We report results of numerical simulations of complex fluids, using a combination of discrete-particle methods. Our molecular modeling repertoire comprises three simulation techniques: molecular dynamics (MD), dissipative particle dynamics (DPD), and the fluid particle model (FPM). This type of model can depict multi-resolution molecular structures found in complex fluids ranging from single micelle, colloidal crystals, large-scale colloidal aggregates up to the mesoscale processes of hydrodynamical instabilities in the bulk of colloidal suspensions. We can simulate different colloidal structures in which the colloidal beds are of comparable size to the solvent particles. This undertaking is accomplished with a two-level discrete particle model consisting of the MD paradigm with a Lennard-Jones (L-J) type potential for defining the colloidal particle system and DPD or FPM for modeling the solvent. We observe the spontaneous emergence of spherical or rod-like micelles and their crystallization in stable hexagonal or worm-like structures, respectively. The ordered arrays obtained by using the particle model are similar to the 2D colloidal crystals observed in laboratory experiments. The micelle shape and its hydrophobic or hydrophilic character depend on the ratio between the scaling factors of the interactions between colloid-colloid to colloid-solvent. Unlike the miscellar arrays, the colloidal aggregates involve the colloid-solvent interactions prescribed by the DPD forces. Different from the assumption of equilibrium growth, the two-level particle model can display much more realistic molecular physics, which allows for the simulation of aggregation for various types of colloids and solvent liquids over a very broad range of conditions. We discuss the potential prospects of combining MD, DPD, and FPM techniques in a single three-level model. Finally, we present results from large-scale simulation of the Rayleigh-Taylor instability and dispersion of colloidal slab