Science.gov

Sample records for controlled particle removal

  1. Transport and Removal experiment of Dust (TReD) for the Dust Particle Controls

    NASA Astrophysics Data System (ADS)

    Woo, Hyun-Jong; Cho, Soon-Gook; Chung, Kyu-Sun; Park, Eun-Kyung; Park, Sang-Joon; Hong, Suk-Ho

    2011-10-01

    The tokamak dust might be hazardous based on the radioactive from tritium or activated metals (e.g. tritium retention), toxic and/or explosive (or chemically reactive) in steam and air conditions. Therefore, controls of dust particle inventory can be treated a critical issue for safe operation of ITER and next step fusion devices. Although the dust removal experiments for fusion reactor had been tried in 1990s, it cannot directly applied to ITER and next step fusion reactors since scale issues does not solved. In this work, one developed the dedicated plasma device for the dust particle transport and removal tests to the level required in ITER or next step fusion reactors (~1 m dust particle transportation), which is called TReD (Transport and Removal experiments of Dust). The TReD also plan to test the dust particle detectors, such as electrostatic dust detector and capacitance diaphragm microbalance (CDM) used (or will be used) in fusion plasmas. The first experimental results of dust particle transport and removal will be explained along with the design concepts, assembly structure, also collaboration plans, etc.

  2. Controlled Gelation of Particle Suspensions Using Controlled Solvent Removal in Picoliter Droplets

    NASA Astrophysics Data System (ADS)

    Vuong, Sharon; Walker, Lynn; Anna, Shelley

    2013-11-01

    Droplets in microfluidic devices have proven useful as uniform picoliter reactors for nanoparticle synthesis and as components in tunable emulsions. However, there can be significant transport between the component phases depending on solubility and other factors. In the present talk, we show that water droplets trapped within a microfluidic device for tens of hours slowly dehydrate, concentrating the contents encapsulated within. We use this slow dehydration along with control of the initial droplet composition to monitor gelation of aqueous suspensions of spherical silica particles (Ludox) and disk-shaped clay particles (Laponite). Droplets are generated in a microfluidic device containing small wells that trap the droplets. We monitor the concentration process through size and shape changes of these droplets as a function of time in tens of droplets and use the large number of individual reactors to generate statistics regarding the gelation process. We also examine changes in suspension viscosity through fluorescent particle tracking as a function of dehydration rate, initial suspension concentration and initial droplet volume, and added salt, and compare the results with the Krieger-Dougherty model in which viscosity increases dramatically with particle volume fraction.

  3. Biological control of the removal of abiogenic particles from the surface ocean

    USGS Publications Warehouse

    Deuser, W.G.; Brewer, P.G.; Jickells, T.D.; Commeau, R.F.

    1983-01-01

    Concurrent measurements of particle concentrations in the near-surface water and of particle fluxes in the deep water of the Sargasso Sea show a close coupling between the two for biogenic components. The concentrations of suspended matter appear to follow an annual cycle similar to that of primary production and deepwater particle flux. Although the concentration of particulate aluminum in the surface water appears to vary randomly with respect to that cycle, the removal of aluminum to deep water is intimately linked to the rapid downward transport of organic matter.

  4. Computerized control of the procedure for detecting and removing airborne particles in operating rooms.

    PubMed

    Bay, Omer Faruk; Ergül, Nesip

    2004-04-01

    Surgical-site infections are still a major problem in modern medicine. Normal skin fora of patients or healthcare workers causes more than half of all infections following clean surgery, but the importance of airborne particles in this setting remains controversial. The use of ultraclean air in operating rooms has been shown to reduce infection rates significantly. High efficiency particlulate air (HEPA) filters are used in some modern operating rooms. Although the uses of HEPA filters, the air quality should be controlled by another device to make safe the air in operating rooms and intensive care units. In this study, a computerized system was established to control the cleanliness of the air by measuring the presence of airborne particles of varying sizes and numbers in operating rooms. When the maximum values are exceeded, the system warns the authorized people by phone, sound, or displays.

  5. Electrohydrodynamic removal of particles from drop surfaces

    NASA Astrophysics Data System (ADS)

    Nudurupati, S.; Janjua, M.; Singh, P.; Aubry, N.

    2009-07-01

    A uniform electric field is used for cleaning drops of the particles they often carry on their surface. In a first step, particles migrate to either the drop’s poles or equator. This is due to the presence of an electrostatic force for which an analytical expression is derived. In a second step, particles concentrated near the poles are released into the ambient liquid via tip streaming, and those near the equator are removed by stretching the drop and breaking it into several droplets. In the latter case, particles are all concentrated in a small middle daughter droplet.

  6. Electrohydrodynamic removal of particles from drop surfaces.

    PubMed

    Nudurupati, S; Janjua, M; Singh, P; Aubry, N

    2009-07-01

    A uniform electric field is used for cleaning drops of the particles they often carry on their surface. In a first step, particles migrate to either the drop's poles or equator. This is due to the presence of an electrostatic force for which an analytical expression is derived. In a second step, particles concentrated near the poles are released into the ambient liquid via tip streaming, and those near the equator are removed by stretching the drop and breaking it into several droplets. In the latter case, particles are all concentrated in a small middle daughter droplet.

  7. Mechanisms for nano particle removal in brush scrubber cleaning

    NASA Astrophysics Data System (ADS)

    Huang, Yating; Guo, Dan; Lu, Xinchun; Luo, Jianbin

    2011-01-01

    A model describing the nano particle (<100 nm) removal behavior in brush scrubber cleaning is presented based on experiment results and theoretical analysis. The forces on the particles in different situations are analyzed and discussed. The adhesion forces of the van der Waals force, the electrostatic force, the brush load and the static friction between the particle and the wafer are calculated. The contact elastic force, hydrodynamic drag force and friction between the brush and the particle are considered as removal forces and are evaluated. The porous structure and roughness surface of brush material are considered in the hydrodynamic model to describe the brush deformation and the flow field in the cleaning process. The porous structure will result in decrease of hydrodynamic drag force. There are four situations of the particles relative to the brush roughness asperities for which the forces on the particle are different. When the particle is in contact with a brush asperity or on the wafer surface and in a semi-infinite fluid flow field, the particle may be removed by hydrodynamic force and elastic force in the presence of surfactant. When the particle is embedded in the brush asperity, the remove will realized when the friction caused by adhesion between the brush and the particle overcome the adhesion force between particle and wafer surface. The removed particles will be in the flow field or adhered on the brush surface and may redeposit on the wafer surface.

  8. Method for removing undesired particles from gas streams

    DOEpatents

    Durham, Michael Dean; Schlager, Richard John; Ebner, Timothy George; Stewart, Robin Michele; Hyatt, David E.; Bustard, Cynthia Jean; Sjostrom, Sharon

    1998-01-01

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency.

  9. Plasma polymer-functionalized silica particles for heavy metals removal.

    PubMed

    Akhavan, Behnam; Jarvis, Karyn; Majewski, Peter

    2015-02-25

    Highly negatively charged particles were fabricated via an innovative plasma-assisted approach for the removal of heavy metal ions. Thiophene plasma polymerization was used to deposit sulfur-rich films onto silica particles followed by the introduction of oxidized sulfur functionalities, such as sulfonate and sulfonic acid, via water-plasma treatments. Surface chemistry analyses were conducted by X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectroscopy. Electrokinetic measurements quantified the zeta potentials and isoelectric points (IEPs) of modified particles and indicated significant decreases of zeta potentials and IEPs upon plasma modification of particles. Plasma polymerized thiophene-coated particles treated with water plasma for 10 min exhibited an IEP of less than 3.5. The effectiveness of developed surfaces in the adsorption of heavy metal ions was demonstrated through copper (Cu) and zinc (Zn) removal experiments. The removal of metal ions was examined through changing initial pH of solution, removal time, and mass of particles. Increasing the water plasma treatment time to 20 min significantly increased the metal removal efficiency (MRE) of modified particles, whereas further increasing the plasma treatment time reduced the MRE due to the influence of an ablation mechanism. The developed particulate surfaces were capable of removing more than 96.7% of both Cu and Zn ions in 1 h. The combination of plasma polymerization and oxidative plasma treatment is an effective method for the fabrication of new adsorbents for the removal of heavy metals.

  10. Accelerated simulation of stochastic particle removal processes in particle-resolved aerosol models

    SciTech Connect

    Curtis, J.H.; Michelotti, M.D.; Riemer, N.; Heath, M.T.; West, M.

    2016-10-01

    Stochastic particle-resolved methods have proven useful for simulating multi-dimensional systems such as composition-resolved aerosol size distributions. While particle-resolved methods have substantial benefits for highly detailed simulations, these techniques suffer from high computational cost, motivating efforts to improve their algorithmic efficiency. Here we formulate an algorithm for accelerating particle removal processes by aggregating particles of similar size into bins. We present the Binned Algorithm for particle removal processes and analyze its performance with application to the atmospherically relevant process of aerosol dry deposition. We show that the Binned Algorithm can dramatically improve the efficiency of particle removals, particularly for low removal rates, and that computational cost is reduced without introducing additional error. In simulations of aerosol particle removal by dry deposition in atmospherically relevant conditions, we demonstrate about 50-times increase in algorithm efficiency.

  11. Method for removing undesired particles from gas streams

    DOEpatents

    Durham, M.D.; Schlager, R.J.; Ebner, T.G.; Stewart, R.M.; Hyatt, D.E.; Bustard, C.J.; Sjostrom, S.

    1998-11-10

    The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency. 11 figs.

  12. Functional polyethersulfone particles for the removal of bilirubin.

    PubMed

    Jiang, Xin; Xiang, Tao; Xie, Yi; Wang, Rui; Zhao, Weifeng; Sun, Shudong; Zhao, Chang-Sheng

    2016-02-01

    In this study, polyethersulfone/poly (glycidyl methacrylate) particles are prepared via in situ cross-linked polymerization coupled with a phase inversion technique. The surfaces of these particles are then further modified by grafting amino groups using tetraethylenepentamine, dethylenetriamine, ethylenediamine, or 1,6-hexanediamine for the removal of bilirubin. The particles are characterized by Flourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Batch adsorption experiments are performed to verify the adsorption capability, and the effect of bilirubin initial concentration, bovine serum albumin concentration, and solution ionic strength on the adsorption is also investigated. In addition, both adsorption kinetic and isotherm models are applied to analyze the adsorption process of bilirubin, and a particle column is used to further study the bilirubin removal ability.To prove that the method was a universal portal to prepare functional particles, polysulfone, polystyrene, and poly(vinylidene fluoride) based functional particles were also prepared and used for the removal of bilirubin. This study and the results indicated that the particles had a great potential to be used in hemoperfusion treatment for hyperbilirubinemia.

  13. Plasma polymerized allylamine coated quartz particles for humic acid removal.

    PubMed

    Jarvis, Karyn L; Majewski, Peter

    2012-08-15

    Allylamine plasma polymerization has been used to modify the surface of quartz particles for humic acid removal via an inductively coupled rotating barrel plasma reactor. Plasma polymerized allylamine (ppAA) films were deposited at a power of 25 W, allylamine flow rate of 4.4 sccm and polymerization times of 5-60 min. The influence of polymerization time on surface chemistry was investigated via X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectrometry (ToF-SIMS) and electrokinetic analysis. Acid orange 7 adsorption/desorption quantified the number of surface amine groups. Humic acid removal via ppAA quartz particles was examined by varying pH, removal time, humic acid concentration, and particle mass. Increasing the polymerization time increased the concentration of amine groups on the ppAA quartz surface, thus also increasing the isoelectric point. ToF-SIMS demonstrated uniform distribution of amine groups across the particle surface. Greatest humic acid removal was observed at pH 5 due to electrostatic attraction. At higher pH values, for longer polymerization times, humic acid removal was also observed due to hydrogen bonding. Increasing the initial humic acid concentration increased the mass of humic acid removed, with longer polymerization times exhibiting the greatest increases. Plasma polymerization using a rotating plasma reactor has shown to be a successful method for modifying quartz particles for the removal of humic acid. Further development of the plasma polymerization process and investigation of additional contaminants will aid in the development of a low cost water treatment system.

  14. Vacuum probe sampler removes micron-sized particles from surfaces

    NASA Technical Reports Server (NTRS)

    Whitfield, W. J.

    1968-01-01

    Vacuum probe sampler removes micron-sized particles from sensitive surfaces, without damage to the surface. The probe has a critical orifice to ensure an optimum airflow rate that disturbs the boundary layer of air and raises bacteria from the surface into the probe with the moving air stream.

  15. Enhanced removal of radioactive particles by fluorocarbon surfactant solutions

    SciTech Connect

    Kaiser, R.; Harling, O.K.

    1993-08-01

    The proposed research addressed the application of ESI`s particle removal process to the non-destructive decontamination of nuclear equipment. The cleaning medium used in this process is a solution of a high molecular weight fluorocarbon surfactant in an inert perfluorinated liquid which results in enhanced particle removal. The perfluorinated liquids of interest, which are recycled in the process, are nontoxic, nonflammable, and environmentally compatible, and do not present a hazard to the ozone layer. The information obtained in the Phase 1 program indicated that the proposed ESI process is technically effective and economically attractive. The fluorocarbon surfactant solutions used as working media in the ESI process survived exposure of up to 10 Mrad doses of gamma rays, and are considered sufficiently radiation resistant for the proposed process. Ultrasonic cleaning in perfluorinated surfactant solutions was found to be an effective method of removing radioactive iron (Fe 59) oxide particles from contaminated test pieces. Radioactive particles suspended in the process liquids could be quantitatively removed by filtration through a 0.1 um membrane filter. Projected economics indicate a pre-tax pay back time of 1 month for a commercial scale system.

  16. Particle fuel delivery control device

    SciTech Connect

    Eshleman, R. D.

    1985-04-30

    A particle fuel burning furnace has an upper combustion chamber for holding a pile of particle fuel and burning the same from the bottom thereof. The furnace also includes a lower combustion chamber for afterburning combustible gases given off by the burning of solid fuel in the upper chamber and a series of spaced apart verrtically-extending passageways arranged in a row and interconnecting the upper and lower chambers for communicating the combustible gases from the upper to the lower chamber. A first improved feature relates to a particle fuel delivery control device which operates an auger for filling the upper chamber with particle fuel to a particle fuel to a desired level. A beam of light is transmitted and reflected between a photoelectric cell and reflector respectively of the device. When the particle fuel pile has grown in height during filling to the desired level the light beam is interrupted and filling is terminated. A second improved feature relates to a particle fuel diversion structure positioned in space relationship above and overlying the row of passageways. The structure forms a horizontal slot which extends laterally from the passageways which prevents particles of fuel from falling rhoguh the passageways and particles of fuel from falling through the passageways and relocates the flame which burns the particle fuel pile from the bottom to a region away from the passageways.

  17. Laser-assisted removal of particles on silicon wafers

    NASA Astrophysics Data System (ADS)

    Vereecke, G.; Röhr, E.; Heyns, M. M.

    1999-04-01

    Laser cleaning is one of the new promising dry cleaning techniques considered by semiconductor companies to replace wet cleans in the near future. A dry laser cleaning tool was tested that uses an inert gas jet to remove particles lifted off by the action of a DUV excimer laser. A model was developed to simulate the cleaning process and analyze the influence of experimental parameters on laser cleaning efficiency. The best cleaning efficiencies obtained with 1.0 μm SiO2, ˜0.3 μm Si3N4, and 0.3 μm SiO2 particles deposited on Si wafers were 84±8%, 33±4%, and 12±7%, respectively. This is in qualitative agreement with theoretical calculations showing the existence of a size threshold for the removal of nonabsorbing particles by dry laser cleaning. Among the process parameters tested to optimize the process efficiency, fluence showed the highest influence on removal efficiency, before the number of laser pulses and the laser repetition rate. The use of high fluences was limited by the damaging of the wafer surface, which was not homogeneous on a macroscopic scale. The optimum number of laser pulses per unit area depended on the type of particle. The laser repetition rate had no significant influence on cleaning efficiency and can be used to reduce process time. The influence of capillary condensation on the process was demonstrated by the higher removal efficiency of 0.3 μm SiO2 and Si3N4 particles, 88±6% and 78%, respectively, upon exposure of wafers to air saturated with moisture prior to laser processing. This was attributed to the explosive evaporation of capillary condensed water, similar to the mechanism proposed for liquid assisted laser cleaning.

  18. Ultrafine particle removal and generation by portable air cleaners

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Siegel, Jeffrey A.; Corsi, Richard L.

    Portable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m 3 stainless steel chamber. In the first phase, particle size-resolved (12.6-514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m 3 h -1; the electrostatic precipitator 284 (62) m 3 h -1; and the two ion generators 41 (11) and 35 (13) m 3 h -1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h -1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h -1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h -1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61-157 nm, and two generated particles in the range of approximately 10 to 39-55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.

  19. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  20. The removal of deformed submicron particles from silicon wafers by spin rinse and megasonics

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Busnaina, Ahmed A.; Fury, Michael A.; Wang, Shi-Qing

    2000-02-01

    In order to successfully clean particulate contamination from wafer surfaces, it is necessary to understand the adhesion and deformation between the particles and the substrate in contact. The adhesion and removal mechanisms of deformed submicron particles have not been addressed in many previous studies. Submicron polystyrene latex particles (0.1-0.5 µm) were deposited on silicon wafers and removed by spin rinse and megasonic cleanings. Particle rolling is identified as the major removal mechanism for the deformed submicron particles from silicon wafers. Megasonics provides larger streaming velocity because of the extremely thin boundary layer resulting in a larger removal force that is capable of achieving complete removal of contamination particles.

  1. Transparent exopolymer particle removal in different drinking water production centers.

    PubMed

    Van Nevel, Sam; Hennebel, Tom; De Beuf, Kristof; Du Laing, Gijs; Verstraete, Willy; Boon, Nico

    2012-07-01

    Transparent exopolymer particles (TEP) have recently gained interest in relation to membrane fouling. These sticky, gel-like particles consist of acidic polysaccharides excreted by bacteria and algae. The concentrations, expressed as xanthan gum equivalents L⁻¹ (μg X(eq) L⁻¹), usually reach hundred up to thousands μg X(eq) L⁻¹ in natural waters. However, very few research was performed on the occurrence and fate of TEP in drinking water, this far. This study examined three different drinking water production centers, taking in effluent of a sewage treatment plant (STP), surface water and groundwater, respectively. Each treatment step was evaluated on TEP removal and on 13 other chemical and biological parameters. An assessment on TEP removal efficiency of a diverse range of water treatment methods and on correlations between TEP and other parameters was performed. Significant correlations between particulate TEP (>0.4 μm) and viable cell concentrations were found, as well as between colloidal TEP (0.05-0.4 μm) and total COD, TOC, total cell or viable cell concentrations. TEP concentrations were very dependent on the raw water source; no TEP was detected in groundwater but the STP effluent contained 1572 μg X(eq) L⁻¹ and the surface water 699 μg X(eq) L⁻¹. Over 94% of total TEP in both plants was colloidal TEP, a fraction neglected in nearly every other TEP study. The combination of coagulation and sand filtration was effective to decrease the TEP levels by 67%, while the combination of ultrafiltration and reverse osmosis provided a total TEP removal. Finally, in none of the installations TEP reached the final drinking water distribution system at significant concentrations. Overall, this study described the presence and removal of TEP in drinking water systems.

  2. Performance of hydroclones for removing particles from viscous liquids

    SciTech Connect

    Talbot, J.B.

    1980-08-01

    The performance of a 1-cm diam, Dorr-Oliver hydroclone with slurries containing approx. 5 wt % solids in water-glycerin solutions was studied to evaluate the effects of fluid viscosity. Micron-sized particles of low-density solids (aluminum oxide, test dust, fly ash, or kaolin) were removed from solutions with viscosities ranging from 1 to 85 cP. Pressure drop across the hydroclone increased with increasing feed rate and viscosity. Gross and centrifugal efficiencies were found to increase with flow rate and decrease with viscosity. Liquid viscosities >10 cP had deleterious effects on the pressure drop and efficiency; thus useful separations were not attained. The particle diameter, corresponding to a point efficiency of 50%, decreased as the product of the inlet Reynolds number and the solid-to-liquid density ratio increased. The reduced efficiency curve was found to characterize the hydroclone performance.

  3. Flow-controlled magnetic particle manipulation

    DOEpatents

    Grate, Jay W [West Richland, WA; Bruckner-Lea, Cynthia J [Richland, WA; Holman, David A [Las Vegas, NV

    2011-02-22

    Inventive methods and apparatus are useful for collecting magnetic materials in one or more magnetic fields and resuspending the particles into a dispersion medium, and optionally repeating collection/resuspension one or more times in the same or a different medium, by controlling the direction and rate of fluid flow through a fluid flow path. The methods provide for contacting derivatized particles with test samples and reagents, removal of excess reagent, washing of magnetic material, and resuspension for analysis, among other uses. The methods are applicable to a wide variety of chemical and biological materials that are susceptible to magnetic labeling, including, for example, cells, viruses, oligonucleotides, proteins, hormones, receptor-ligand complexes, environmental contaminants and the like.

  4. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, William K.

    1986-01-01

    A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

  5. Removal of toxic uranium from synthetic nuclear power reactor effluents using uranyl ion imprinted polymer particles.

    PubMed

    Preetha, Chandrika Ravindran; Gladis, Joseph Mary; Rao, Talasila Prasada; Venkateswaran, Gopala

    2006-05-01

    Major quantities of uranium find use as nuclear fuel in nuclear power reactors. In view of the extreme toxicity of uranium and consequent stringent limits fixed by WHO and various national governments, it is essential to remove uranium from nuclear power reactor effluents before discharge into environment. Ion imprinted polymer (IIP) materials have traditionally been used for the recovery of uranium from dilute aqueous solutions prior to detection or from seawater. We now describe the use of IIP materials for selective removal of uranium from a typical synthetic nuclear power reactor effluent. The IIP materials were prepared for uranyl ion (imprint ion) by forming binary salicylaldoxime (SALO) or 4-vinylpyridine (VP) or ternary SALO-VP complexes in 2-methoxyethanol (porogen) and copolymerizing in the presence of styrene (monomer), divinylbenzene (cross-linking monomer), and 2,2'-azobisisobutyronitrile (initiator). The resulting materials were then ground and sieved to obtain unleached polymer particles. Leached IIP particles were obtained by leaching the imprint ions with 6.0 M HCl. Control polymer particles were also prepared analogously without the imprint ion. The IIP particles obtained with ternary complex alone gave quantitative removal of uranyl ion in the pH range 3.5-5.0 with as low as 0.08 g. The retention capacity of uranyl IIP particles was found to be 98.50 mg/g of polymer. The present study successfully demonstrates the feasibility of removing uranyl ions selectively in the range 5 microg - 300 mg present in 500 mL of synthetic nuclear power reactor effluent containing a host of other inorganic species.

  6. Process and apparatus for adding and removing particles from pressurized reactors

    DOEpatents

    Milligan, John D.

    1983-01-01

    A method for adding and removing fine particles from a pressurized reactor is provided, which comprises connecting the reactor to a container, sealing the container from the reactor, filling the container with particles and a liquid material compatible with the reactants, pressurizing the container to substantially the reactor pressure, removing the seal between the reactor and the container, permitting particles to fall into or out of the reactor, and resealing the container from the reactor. An apparatus for adding and removing particles is also disclosed.

  7. Conditions for laser-induced plasma to effectively remove nano-particles on silicon surfaces

    NASA Astrophysics Data System (ADS)

    Han, Jinghua; Luo, Li; Zhang, Yubo; Hu, Ruifeng; Feng, Guoying

    2016-09-01

    Particles can be removed from a silicon surface by means of irradiation and a laser plasma shock wave. The particles and silicon are heated by the irradiation and they will expand differently due to their different expansion coefficients, making the particles easier to be removed. Laser plasma can ionize and even vaporize particles more significantly than an incident laser and, therefore, it can remove the particles more efficiently. The laser plasma shock wave plays a dominant role in removing particles, which is attributed to its strong burst force. The pressure of the laser plasma shock wave is determined by the laser pulse energy and the gap between the focus of laser and substrate surface. In order to obtain the working conditions for particle removal, the removal mechanism, as well as the temporal and spatial characteristics of velocity, propagation distance and pressure of shock wave have been researched. On the basis of our results, the conditions for nano-particle removal are achieved. Project supported by the National Natural Science Foundation of China (Grant No. 11574221).

  8. Ultrafine particle removal and ozone generation by in-duct electrostatic precipitators.

    PubMed

    Poppendieck, Dustin G; Rim, Donghyun; Persily, Andrew K

    2014-01-01

    Human exposure to airborne ultrafine particles (UFP, < 100 nm) has been shown to have adverse health effects and can be elevated in buildings. In-duct electrostatic precipitator filters (ESP) have been shown to be an effective particulate control device for reducing UFP concentrations (20-100 nm) in buildings, although they have the potential to increase indoor ozone concentrations. This study investigated residential ESP filters to reduce ultrafine particles between 4 to 15 nm and quantified the resulting ozone generation. In-duct ESPs were operated in the central air handling unit of a test house. Results for the two tested ESP brands indicate that removal efficiency of 8 to 14 nm particles was near zero and always less than 10% (± 15%), possibly due to particle generation or low charging efficiency. Adding a media filter downstream of the ESP increased the decay rate for particles in the same size range. Continuous operation of one brand of ESP raised indoor ozone concentrations to 77 ppbv and 20 ppbv for a second brand. Using commercial filters containing activated carbon downstream of the installed ESP reduced the indoor steady-state ozone concentrations between 6% and 39%.

  9. Material removal mechanism and material removal rate model of polishing process for quartz glass using soft particle

    NASA Astrophysics Data System (ADS)

    Liu, Defu; Chen, Guanglin; Hu, Qing

    2015-10-01

    Fiber arrays are used to connect arrayed waveguide chips. The end-faces of fiber array components are multi-materials non-uniform surfaces. Their low polishing quality has become a bottleneck that restricts coupling performance of integrated photo-electronic devices. The chemical mechanical polishing (CMP) is normally used to improve the polishing quality of the end-faces of fiber array components. It is very important to optimize process parameters by researching the mechanical behavior of nanoparticles and material microstructure evolution on the CMP interfaces. Based on the elastic and hyper-elastic contact of the soft polishing particle with quartz glass and polishing pad, the material removal mechanism at molecular scale of polishing process for quartz glass using soft polishing particles is investigated, and the material removal rate model is also derived by using Arrhenius theory and molecule vibration theory. Theoretical and experimental results show that the material is mainly removed by the interfacial tribo-chemical effect between polishing particle and quartz glass during CMP process. The depth of a single particle embedding into the quartz glass is at molecular scale, and the superficial molecules of quartz glass are removed by chemical reactions because of enough energy obtained. The material removal rate of quartz glass during CMP process is determined by the polishing pressure, the chemical reagents and its concentration, and the relative movement speed between the quartz glass workpiece and the polishing pad.

  10. Removal of virus to protozoan sized particles in point-of-use ceramic water filters.

    PubMed

    Bielefeldt, Angela R; Kowalski, Kate; Schilling, Cherylynn; Schreier, Simon; Kohler, Amanda; Scott Summers, R

    2010-03-01

    The particle removal performance of point-of-use ceramic water filters (CWFs) was characterized in the size range of 0.02-100 microm using carboxylate-coated polystyrene fluorescent microspheres, natural particles and clay. Particles were spiked into dechlorinated tap water, and three successive water batches treated in each of six different CWFs. Particle removal generally increased with increasing size. The removal of virus-sized 0.02 and 0.1 microm spheres were highly variable between the six filters, ranging from 63 to 99.6%. For the 0.5 microm spheres removal was less variable and in the range of 95.1-99.6%, while for the 1, 2, 4.5, and 10 microm spheres removal was >99.6%. Recoating four of the CWFs with colloidal silver solution improved removal of the 0.02 microm spheres, but had no significant effects on the other particle sizes. Log removals of 1.8-3.2 were found for natural turbidity and spiked kaolin clay particles; however, particles as large as 95 microm were detected in filtered water.

  11. Policy on management of post-removal site control. Directive

    SciTech Connect

    Not Available

    1990-12-03

    The directive transmits the OSWER policy on management of post-removal site control for Fund-financed removal activities and communicating decisions to States on the use of institutional controls. It provides procedures to ensure that, when necessary and to the extent practicable, provision for post-removal site control at both National Priorities List (NPL) and non-NPL sites is made prior to initiation of a Fund-financed removal action. Procedures are also provided for communicating decisions to States on the use of institutional controls when waste is left on-site following a removal action.

  12. Apparatus and method for removing particle species from fusion-plasma-confinement devices

    DOEpatents

    Hamilton, G.W.

    1981-10-26

    In a mirror fusion plasma confinement apparatus, method and apparatus are provided for selectively removing (pumping) trapped low energy (thermal) particle species from the end cell region, without removing the still useful high energy particle species, and without requiring large power input to accomplish the pumping. Perturbation magnets are placed in the thermal barrier region of the end cell region at the turning point characteristic of trapped thermal particles, thus deflecting the thermal particles from their closed trajectory, causing them to drift sufficiently to exit the thermal barrier.

  13. Toner display based on particle control technologies

    NASA Astrophysics Data System (ADS)

    Kitamura, Takashi

    2011-03-01

    Toner Display is based on an electrical movement of charged particles. Two types of black toner and white particles charged in the different electric polarity are enclosed between two electrodes. The particle movement is controlled by the external electric field applied between two transparent electrodes. The toner is collected to the electrode by an electrostatic force across the insulating layer to display a black image. The toners can be put back to the counter electrode by applying a reverse electric field, and white solid image is displayed. We have studied on the movement of three color particles independently to display color image in Toner Display. Two positively charged color particles with different amount of charge to mass ratio and negatively charged white particles were enclosed in the toner display cell. Yellow, cyan and white images were displayed by an application of voltage.

  14. Removal of Waterborne Particles by Electrofiltration: Pilot-Scale Testing

    EPA Science Inventory

    Theoretical analysis using a trajectory approach indicated that in the presence of an external electric field, charged waterborne particles are subject to an additional migration velocity which increases their deposition on the surface of collectors (e.g. sand filter). In this st...

  15. Effect of AC Electrostatic Precipitator on Removal Diesel Exhaust Particles

    NASA Astrophysics Data System (ADS)

    Kawakami, Hitomi; Zukeran, Akinori; Yasumoto, Koji; Kubojima, Masaki; Ehara, Yoshiyasu; Yamamoto, Toshiaki

    Collection of low resistive particulate matter (PM) generated from automobile and marine diesel engines or diesel generators have been known to be difficult by the conventional electrostatic precipitators (ESP). The collection efficiency for two types ESPs such as conventional DC energized ESP (DC ESP) and rectangular-AC-waveform energized ESP (AC ESP) were investigated. The low resistive PMs agglomerate like a pearl-chain on the collection plate in DC ESP, so that these are detached from the collection plate by electrostatic repulsion force and wind force. The pearl-chain particles are changed the shape, which is such a spherical, by AC ESP. Therefore, the particle re-entrainment is suppressed by AC ESP.

  16. A key process controlling the wet removal of aerosols: new observational evidence

    NASA Astrophysics Data System (ADS)

    Ohata, Sho; Moteki, Nobuhiro; Mori, Tatsuhiro; Koike, Makoto; Kondo, Yutaka

    2016-10-01

    The lifetime and spatial distributions of accumulation-mode aerosols in a size range of approximately 0.05–1 μm, and thus their global and regional climate impacts, are primarily constrained by their removal via cloud and precipitation (wet removal). However, the microphysical process that predominantly controls the removal efficiency remains unidentified because of observational difficulties. Here, we demonstrate that the activation of aerosols to cloud droplets (nucleation scavenging) predominantly controls the wet removal efficiency of accumulation-mode aerosols, using water-insoluble black carbon as an observable particle tracer during the removal process. From simultaneous ground-based observations of black carbon in air (prior to removal) and in rainwater (after removal) in Tokyo, Japan, we found that the wet removal efficiency depends strongly on particle size, and the size dependence can be explained quantitatively by the observed size-dependent cloud-nucleating ability. Furthermore, our observational method provides an estimate of the effective supersaturation of water vapour in precipitating cloud clusters, a key parameter controlling nucleation scavenging. These novel data firmly indicate the importance of quantitative numerical simulations of the nucleation scavenging process to improve the model’s ability to predict the atmospheric aerosol burden and the resultant climate forcings, and enable a new validation of such simulations.

  17. A key process controlling the wet removal of aerosols: new observational evidence

    PubMed Central

    Ohata, Sho; Moteki, Nobuhiro; Mori, Tatsuhiro; Koike, Makoto; Kondo, Yutaka

    2016-01-01

    The lifetime and spatial distributions of accumulation-mode aerosols in a size range of approximately 0.05–1 μm, and thus their global and regional climate impacts, are primarily constrained by their removal via cloud and precipitation (wet removal). However, the microphysical process that predominantly controls the removal efficiency remains unidentified because of observational difficulties. Here, we demonstrate that the activation of aerosols to cloud droplets (nucleation scavenging) predominantly controls the wet removal efficiency of accumulation-mode aerosols, using water-insoluble black carbon as an observable particle tracer during the removal process. From simultaneous ground-based observations of black carbon in air (prior to removal) and in rainwater (after removal) in Tokyo, Japan, we found that the wet removal efficiency depends strongly on particle size, and the size dependence can be explained quantitatively by the observed size-dependent cloud-nucleating ability. Furthermore, our observational method provides an estimate of the effective supersaturation of water vapour in precipitating cloud clusters, a key parameter controlling nucleation scavenging. These novel data firmly indicate the importance of quantitative numerical simulations of the nucleation scavenging process to improve the model’s ability to predict the atmospheric aerosol burden and the resultant climate forcings, and enable a new validation of such simulations. PMID:27703169

  18. Controlled morphological structure of magnesium oxide particles

    NASA Astrophysics Data System (ADS)

    Pradita, T.; Aji, B. B.; Shih, S. J.; Sudibyo

    2017-03-01

    Magnesium Oxide (MgO) based material have been widely used as catalyst, paints, flame retardants, semiconductors, additives in refractory and solid adsorbent. Morphology of a particle has significant influence towards their application. MgO particles were prepared from Magnesium Acetate (MgAc) and Magnesium Nitrate (MgN) precursors using ultrasonic spray pyrolysis method (SP). The MgO particles were characterized by thermogravimetry analysis (TGA), X-Ray Diffraction Analysis (XRD), Field Emission-Secondary Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM). This experimental study results each precursor could have more than one morphologies. It also suggests that the morphology of the MgO particles were controlled by the selection of the precursor, each precursor possess different particle formation characteristic, including the different crystallization rate and also related from the different decomposition behavior during the heating process of SP.

  19. Hydraulic gradient control for groundwater contaminant removal

    USGS Publications Warehouse

    Fisher, Atwood D.; Gorelick, S.M.

    1985-01-01

    The Rocky Mountain Arsenal near Denver, Colarado, U.S.A., is used as a realistic setting for a hypothetical test of a procedure that plans the hydraulic stabilization and removal of a groundwater contaminant plume. A two-stage planning procedure successfully selects the best wells and their optimal pumping/recharge schedules to contain the plume while a well or system of wells within the plume removes the contaminated water. In stage I, a combined groundwater flow and solute transport model is used to simulate contaminant removal under an assumed velocity field. The result is the approximated plume boundary location as a function of time. In stage II, a linear program, which includes a groundwater flow model as part of the set of constraints, determines the optimal well selection and their optimal pumping/recharge schedules by minimizing total pumping and recharge. The simulation-management model eliminates wells far from the plume perimeter and activates wells near the perimeter as the plume decreases in size. This successfully stablizes the hydraulic gradient during aquifer cleanup.The Rocky Mountain Arsenal near Denver, Colorado, USA, is used as a realistic setting for a hypothetical test of a procedure that plans the hydraulic stabilization and removal of a groundwater contaminant plume. A two-stage planning procedure successfully selects the best wells and their optimal pumping/recharge schedules to contain the plume while a well or system of wells within the plume removes the contaminated water. In stage I, a combined groundwater flow and solute transport model is used to simulate contaminant removal under an assumed velocity field. The result is the approximated plume boundary location as a function of time. In stage II, a linear program, which includes a groundwater flow model as part of the set of constraints, determines the optimal well selection and their optimal pumping/recharge schedules by minimizing total pumping and recharge. Refs.

  20. Particle retention in suspension-feeding fish after removal of filtration structures.

    PubMed

    Smith, Jennifer C; Sanderson, S Laurie

    2013-12-01

    The suspension-feeding cichlids Oreochromis aureus (blue tilapia) and Oreochromis esculentus (ngege tilapia) are able to selectively retain small food particles. The gill rakers and microbranchiospines of these species have been assumed to function as filters. However, surgical removal of these oral structures, which also removed associated mucus, did not significantly affect the total number of 11-200 μm particles ingested by the fish. This result supports the hypothesis that the branchial arch surfaces themselves play an important role in crossflow filtration. Both species selectively retained microspheres greater than 50 μm with gill rakers and microbranchiospines intact as well as removed, demonstrating that neither these structures nor mucus are necessary for size selectivity to occur during biological crossflow filtration. After removal of the gill rakers and microbranchiospines, O. esculentus retained significantly more microspheres 51-70 μm in diameter and fewer 91-130 μm microspheres compared to retention with intact structures, but the particle size selectivity of O. aureus was not affected significantly. These results support conclusions from previous computational fluid dynamics simulations indicating that particle size can have marked effects on particle trajectory and retention inside the fish oropharyngeal cavity during crossflow filtration. The substantial inter-individual variability in particle retention by suspension-feeding fish is an unexplored area of research with the potential to increase our understanding of the factors influencing particle retention during biological filtration.

  1. Ice nucleation active particles are efficiently removed by precipitating clouds.

    PubMed

    Stopelli, Emiliano; Conen, Franz; Morris, Cindy E; Herrmann, Erik; Bukowiecki, Nicolas; Alewell, Christine

    2015-11-10

    Ice nucleation in cold clouds is a decisive step in the formation of rain and snow. Observations and modelling suggest that variations in the concentrations of ice nucleating particles (INPs) affect timing, location and amount of precipitation. A quantitative description of the abundance and variability of INPs is crucial to assess and predict their influence on precipitation. Here we used the hydrological indicator δ(18)O to derive the fraction of water vapour lost from precipitating clouds and correlated it with the abundance of INPs in freshly fallen snow. Results show that the number of INPs active at temperatures ≥ -10 °C (INPs-10) halves for every 10% of vapour lost through precipitation. Particles of similar size (>0.5 μm) halve in number for only every 20% of vapour lost, suggesting effective microphysical processing of INPs during precipitation. We show that INPs active at moderate supercooling are rapidly depleted by precipitating clouds, limiting their impact on subsequent rainfall development in time and space.

  2. Ice nucleation active particles are efficiently removed by precipitating clouds

    PubMed Central

    Stopelli, Emiliano; Conen, Franz; Morris, Cindy E.; Herrmann, Erik; Bukowiecki, Nicolas; Alewell, Christine

    2015-01-01

    Ice nucleation in cold clouds is a decisive step in the formation of rain and snow. Observations and modelling suggest that variations in the concentrations of ice nucleating particles (INPs) affect timing, location and amount of precipitation. A quantitative description of the abundance and variability of INPs is crucial to assess and predict their influence on precipitation. Here we used the hydrological indicator δ18O to derive the fraction of water vapour lost from precipitating clouds and correlated it with the abundance of INPs in freshly fallen snow. Results show that the number of INPs active at temperatures ≥ −10 °C (INPs−10) halves for every 10% of vapour lost through precipitation. Particles of similar size (>0.5 μm) halve in number for only every 20% of vapour lost, suggesting effective microphysical processing of INPs during precipitation. We show that INPs active at moderate supercooling are rapidly depleted by precipitating clouds, limiting their impact on subsequent rainfall development in time and space. PMID:26553559

  3. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Ohio § 52.1890 Removed control measures. On the dates listed below, Ohio requested that the indicated control measures be removed from the Ohio State Implementation Plan (SIP). (a) On February 21, 1997, the State of Ohio requested that...

  4. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Ohio § 52.1890 Removed control measures. On the dates listed below, Ohio requested that the indicated control measures be removed from the Ohio State Implementation Plan (SIP). (a) On February 21, 1997, the State of Ohio requested that...

  5. Optimization of removal function in computer controlled optical surfacing

    NASA Astrophysics Data System (ADS)

    Chen, Xi; Guo, Peiji; Ren, Jianfeng

    2010-10-01

    The technical principle of computer controlled optical surfacing (CCOS) and the common method of optimizing removal function that is used in CCOS are introduced in this paper. A new optimizing method time-sharing synthesis of removal function is proposed to solve problems of the removal function being far away from Gaussian type and slow approaching of the removal function error that encountered in the mode of planet motion or translation-rotation. Detailed time-sharing synthesis of using six removal functions is discussed. For a given region on the workpiece, six positions are selected as the centers of the removal function; polishing tool controlled by the executive system of CCOS revolves around each centre to complete a cycle in proper order. The overall removal function obtained by the time-sharing process is the ratio of total material removal in six cycles to time duration of the six cycles, which depends on the arrangement and distribution of the six removal functions. Simulations on the synthesized overall removal functions under two different modes of motion, i.e., planet motion and translation-rotation are performed from which the optimized combination of tool parameters and distribution of time-sharing synthesis removal functions are obtained. The evaluation function when optimizing is determined by an approaching factor which is defined as the ratio of the material removal within the area of half of the polishing tool coverage from the polishing center to the total material removal within the full polishing tool coverage area. After optimization, it is found that the optimized removal function obtained by time-sharing synthesis is closer to the ideal Gaussian type removal function than those by the traditional methods. The time-sharing synthesis method of the removal function provides an efficient way to increase the convergence speed of the surface error in CCOS for the fabrication of aspheric optical surfaces, and to reduce the intermediate- and high

  6. ASSESSMENT OF BIOFILTER MEDIA PARTICLE SIZES FOR REMOVING AMMONIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

  7. Assessment of Biofilter Media Particle Sizes for Removing Ammonia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With increased concerns over odor and gas emissions from livestock production facilities more efficient technologies of air pollution control are needed to mitigate the deleterious effects of air contaminants. Gas-phase biofilters for treating contaminant gases from poultry and livestock operations ...

  8. Dephasing-controlled particle transport devices

    NASA Astrophysics Data System (ADS)

    Kapetanović, Edin; Rodríguez-Rosario, César A.; Frauenheim, Thomas

    2016-12-01

    We study the role of dephasing in transport through different structures. We show that interference effects invalidate Kirchhoff's circuit laws in quantum devices and illustrate the emergence of Ohmic conduction under strong dephasing. We present circuits where the particle transport and the direction of rectification can be controlled through the dephasing strength. This suggests the possibility of constructing molecular devices with new functionalities which use dephasing as a control parameter.

  9. Rock sampling. [apparatus for controlling particle size

    NASA Technical Reports Server (NTRS)

    Blum, P. (Inventor)

    1971-01-01

    An apparatus for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The device includes grinding means for cutting grooves in the rock surface and to provide a grouping of thin, shallow, parallel ridges and cutter means to reduce these ridges to a powder specimen. Collection means is provided for the powder. The invention relates to rock grinding and particularly to the sampling of rock specimens with good size control.

  10. Removal of particles from lithographic masks through plasma-assisted cleaning by metastable atomic neutralization

    NASA Astrophysics Data System (ADS)

    Lytle, W. M.; Szybilski, D. S.; Das, C. E.; Raju, R.; Surla, V.; Neumann, M. J.; Ruzic, D. N.

    2008-11-01

    For extreme ultraviolet lithography (EUVL) to become a high volume manufacturing technology for integrated circuit manufacturing, the cleanliness of the system, especially the photomask, is of high importance. For EUV photomasks, which cannot be protected from contamination by the use of a pellicle, an effective and quick cleaning technology needs to be ready in order to maintain wafer throughput. There are challenges to extend current wet cleaning technologies to meet the future needs for damage-free and high efficiency mask cleaning. Accordingly, a unique process for cleaning particulates from surfaces, specifically photomasks as well as wafers, has been evaluated at the University of Illinois Urbana-Champaign. The removal technique utilizes a high density plasma source as well as pulsed substrate biases to provide for removal. Helium is used as the primary gas in the plasma, which under ionization, provides for a large density of helium metastable atoms present in the plasma. These metastable helium atoms have on the order of 20 eV of energy which can transfer to particles on the substrate to be cleaned. When the substrate is under a small flux of ion bombardment, these bonds then remain broken and it is theorized that this allows the particles to be volatilized for their subsequent removal. 100 % particle removal efficiency has been obtained for 30 nm, 80 nm, and 200 nm polystyrene latex particles. In addition, removal rate has been correlated with helium metastable population density determined by optical emission spectroscopy.

  11. Alternate particle removal technologies for the Airborne Activity Confinement System at the Savannah River Site

    SciTech Connect

    Brockmann, J.E.; Adkins, C.L.J.; Gelbard, F.

    1991-09-01

    This report presents a review of the filtration technologies available for the removal of particulate material from a gas stream. It was undertaken to identify alternate filtration technologies that may be employed in the Airborne Activity Confinement System (AACS) at the Savannah River Plant. This report is organized into six sections: (1) a discussion of the aerosol source term and its definition, (2) a short discussion of particle and gaseous contaminant removal mechanisms, (3) a brief overview of particle removal technologies, (4) a discussion of the existing AACS and its potential shortcomings, (5) an enumeration of issues to be addressed in upgrading the AACS, and, (6) a detailed discussion of the identified technologies. The purpose of this report is to identity available options to the existing particle removal system. This system is in continuous operation during routine operation of the reactor. As will be seen, there are a number of options and the selection of any technology or combination of technologies will depend on the design aerosol source term (yet to be appropriately defined) as well as the flow requirements and configuration. This report does not select a specific technology. It focuses on particulate removal and qualitatively on the removal of radio-iodine and mist elimination. Candidate technologies have been selected from industrial and nuclear gas cleaning applications.

  12. Particle removal challenges with EUV patterned mask for the sub-22nm HP node

    SciTech Connect

    Rastegar, A.; Eichenlaub, S.; Kadaksham, A. J.; Lee, B.; House, M.; Huh, S.; Cha, B.; Yun, H.; Mochi, I.; Goldberg, K. A.

    2010-03-12

    The particle removal efficiency (PRE) of cleaning processes diminishes whenever the minimum defect size for a specific technology node becomes smaller. For the sub-22 nm half-pitch (HP) node, it was demonstrated that exposure to high power megasonic up to 200 W/cm{sup 2} did not damage 60 nm wide TaBN absorber lines corresponding to the 16 nm HP node on wafer. An ammonium hydroxide mixture and megasonics removes {ge}50 nm SiO{sub 2} particles with a very high PRE, A sulfuric acid hydrogen peroxide mixture (SPM) in addition to ammonium hydroxide mixture (APM) and megasonic is required to remove {ge}28 nm SiO{sub 2} particles with a high PRE. Time-of-flight secondary ion mass spectroscopy (TOFSIMS) studies show that the presence of O{sub 2} during a vacuum ultraviolet (VUV) ({lambda} = 172 nm) surface conditioning step will result in both surface oxidation and Ru removal, which drastically reduce extreme ultraviolet (EUV) mask life time under multiple cleanings. New EUV mask cleaning processes show negligible or no EUV reflectivity loss and no increase in surface roughness after up to 15 cleaning cycles. Reviewing of defect with a high current density scanning electron microscope (SEM) drastically reduces PRE and deforms SiO{sub 2} particles. 28 nm SiO{sub 2} particles on EUV masks age very fast and will deform over time, Care must be taken when reviewing EUV mask defects by SEM. Potentially new particles should be identified to calibrate short wavelength inspection tools, Based on actinic image review, 50 nm SiO{sub 2} particles on top of the EUV mask will be printed on the wafer.

  13. Effect of weathering on mobilization of biochar particles and bacterial removal in a stormwater biofilter.

    PubMed

    Mohanty, Sanjay K; Boehm, Alexandria B

    2015-11-15

    To improve bacterial removal, a traditional stormwater biofilter can be augmented with biochar, but it is unknown whether bacterial removal remains consistent as the biochar weathers during intermittent exposure to stormwater under dry-wet and freeze-thaw cycles. To examine the effect of weathering on bacterial removal capacity of biochar, we subjected biochar-augmented sand filters (or simplified biofilters) to multiple freeze-thaw or dry-wet cycles for a month and then compared their bacterial removal capacity with the removal capacity of unweathered biofilters. To isolate the effect of physical and chemical weathering processes from that of biological processes, the biofilters were operated without any developed biofilm. Biochar particles were mobilized during intermittent infiltration of stormwater, but the mobilization depended on temperature and antecedent conditions. During stormwater infiltration without intermediate drying, exposure to natural organic matter (NOM) in the stormwater decreased the bacterial removal capacity of biochar, partly due to exhaustion of attachment sites by NOM adsorption. In contrast, exposure to the same amount of NOM during stormwater infiltration with intermediate drying resulted in higher bacterial removal. This result suggests that dry-wet cycles may enhance recovery of the previously exhausted attachment sites, possibly due to diffusion of NOM from biochar surfaces into intraparticle pores during intermediate drying periods. Overall, these results indicate that physical weathering has net positive effect on bacterial removal by biochar-augmented biofilters.

  14. A concept of an automated function control for ambient aerosol measurements using mobility particle size spectrometers

    NASA Astrophysics Data System (ADS)

    Bastian, S.; Löschau, G.; Wiedensohler, A.

    2014-04-01

    An automated function control unit was developed to regularly check the ambient particle number concentration derived from a mobility particle size spectrometer as well as its zero-point behaviour. The function control allows unattended quality assurance experiments at remote air quality monitoring or research stations under field conditions. The automated function control also has the advantage of being able to get a faster system stability response than the recommended on-site comparisons with reference instruments. The method is based on a comparison of the total particle number concentration measured by a mobility particle size spectrometer and a condensation particle counter while removing diffusive particles smaller than 20 nm in diameter. In practice, the small particles are removed by a set of diffusion screens, as traditionally used in a diffusion battery. Another feature of the automated function control is to check the zero-point behaviour of the ambient aerosol passing through a high-efficiency particulate air (HEPA) filter. The performance of the function control is illustrated with the aid of a 1-year data set recorded at Annaberg-Buchholz, a station in the Saxon air quality monitoring network. During the period of concern, the total particle number concentration derived from the mobility particle size spectrometer slightly overestimated the particle number concentration recorded by the condensation particle counter by 2 % (grand average). Based on our first year of experience with the function control, we developed tolerance criteria that allow a performance evaluation of a tested mobility particle size spectrometer with respect to the total particle number concentration. We conclude that the automated function control enhances the quality and reliability of unattended long-term particle number size distribution measurements. This will have beneficial effects for intercomparison studies involving different measurement sites, and help provide a higher

  15. Kinetic analysis of competition between aerosol particle removal and generation by ionization air purifiers.

    PubMed

    Alshawa, Ahmad; Russell, Ashley R; Nizkorodov, Sergey A

    2007-04-01

    Ionization air purifiers are increasingly used to remove aerosol particles from indoor air. However, certain ionization air purifiers also emit ozone. Reactions between the emitted ozone and unsaturated volatile organic compounds (VOC) commonly found in indoor air produce additional respirable aerosol particles in the ultrafine (<0.1 microm) and fine (<2.5 microm) size domains. A simple kinetic model is used to analyze the competition between the removal and generation of particulate matter by ionization air purifiers under conditions of a typical residential building. This model predicts that certain widely used ionization air purifiers may actually increase the mass concentration of fine and ultrafine particulates in the presence of common unsaturated VOC, such as limonene contained in many household cleaning products. This prediction is supported by an explicit observation of ultrafine particle nucleation events caused by the addition of D-limonene to a ventilated office room equipped with a common ionization air purifier.

  16. Optimization of Microdermabrasion for Controlled Removal of Stratum Corneum

    PubMed Central

    Andrews, Samantha N.; Zarnitsyn, Vladimir; Brian, Bondy; Prausnitz, Mark R.

    2011-01-01

    Microdermabrasion has been shown to increase skin permeability for transdermal drug delivery by damaging or removing skin’s outer layer, stratum corneum. However, relationships between microdermabrasion parameters and effects on the stratum corneum barrier have not been developed. In this study, we determined the effect of microdermabrasion crystal flow rate, time, and suction pressure applied in both static and dynamic modes on the extent of stratum corneum removal from excised porcine skin. In addition to controlling the depth of tissue removal by microdermabrasion parameters, we also controlled the area of tissue removal by applying a metal mask patterned with 125- or 250-μm holes to selectively expose small spots of tissue to microdermabrasion. We found that the extent of stratum corneum removal depended strongly on the crystal flow rate and exposure time and only weakly on pressure or static/dynamic mode operation. Masking the skin was effective to localize stratum corneum removal to exposed sites. Overall, this study demonstrates that optimized microdermabrasion in combination with a mask can be used to selectively remove stratum corneum with three-dimensional control, which is important to translating this technique into a novel method of transdermal drug delivery. PMID:21272628

  17. Optimization of circular plate separators with cross flow for removal of oil droplets and solid particles.

    PubMed

    Ngu, Hei; Wong, Kien Kuok; Law, Puong Ling

    2012-04-01

    A circular gravity-phase separator using coalescing medium with cross flow was developed to remove oil and suspended solids from wastewaters. Coalescence medium in the form of inclined plates promotes rising of oil droplets through coalescence and settling of solid particles through coagulation. It exhibits 22.67% higher removal of total suspended solids (TSS) compared to separators without coalescing medium. Moreover, it removed more than 70% of oil compared to conventional American Petroleum Institute separators, which exhibit an average of 33% oil removal. The flowrate required to attain an effluent oil concentration of 10 mg/L (Q(o10)) at different influent oil concentrations (C(io)) can be represented by Q(o10) x 10(-5) = -0.0012C(io) + 0.352. The flowrate required to attain an effluent TSS concentration of 50 mg/L (Q(ss50)) at different influent TSS concentrations (C(iss)) can be represented by Q(ss50) x 10(-5) = 1.0 x 10(6) C(iss)(-2.9576). The smallest removable solid particle size was 4.87 microm.

  18. Extrinsic stain removal with a toothpowder: A randomized controlled trial

    PubMed Central

    Khan, Muhammad Khalil; Bokhari, Syed Akhtar Hussain; Haleem, Abdul; Kareem, Abdul; Khan, Ayyaz Ali; Hosein, Tasleem; Khan, Muhammad Usama

    2014-01-01

    Objectives The efficacy of a commercially available toothpowder was compared with toothpaste in removing extrinsic dental stains. Methods In this single-blind, randomized controlled trial, 77 volunteers were included from a residential professional college. All study subjects (control toothpaste users and test toothpowder users) plaque control measures. All study subjects were instructed to rinse with 5 ml 0.12% chlorhexidine mouthwash for 1 minute, twice and one cup of double tea bag solution three times daily for three weeks. Subjects were randomized into test (n=36) and control (n=36) groups. Toothpaste (control) and toothpowder (test) was used for two weeks to see the effects on removing stains on the labial surfaces of 12 anterior teeth. For measuring dental extrinsic stains Lobene Stain Index (SI) was used. Results The amount of stain following the use of toothpaste and toothpowder was more controlled with the experimental toothpowder. For all sites combined, there was evidence that the experimental toothpowder was significantly superior to toothpaste in reducing stain area (p<.001), stain intensity (p<.001) and composite/product (area × intensity) (p<.001). Conclusion Stain removing efficacy of toothpowder was significantly higher as compared with toothpaste. A toothpowder may be expected to be of benefit in controlling and removing extrinsic dental staining. PMID:25505862

  19. Experimental investigation of submicron and ultrafine soot particle removal by tree leaves

    NASA Astrophysics Data System (ADS)

    Hwang, Hee-Jae; Yook, Se-Jin; Ahn, Kang-Ho

    2011-12-01

    Soot particles emitted from vehicles are one of the major sources of air pollution in urban areas. In this study, five kinds of trees were selected as Pinus densiflora, Taxus cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba, and the removal of submicron (<1 μm) and ultrafine (<0.1 μm) soot particles by tree leaves was quantitatively compared in terms of deposition velocity. Soot particles were produced by a diffusion flame burner using acetylene as the fuel. The sizes of monodisperse soot particles classified with the Differential Mobility Analyzers (DMA) were 30, 55, 90, 150, 250, 400, and 600 nm. A deposition chamber was designed to simulate the omni-directional flow condition around the tree leaves. Deposition velocities onto the needle-leaf trees were higher than those onto the broadleaf trees. P. densiflora showed the greatest deposition velocity, followed by T. cuspidata, Platanus occidentalis, Zelkova serrata, and Ginkgo biloba. In addition, from the comparison of deposition velocity between two groups of Platanus occidentalis leaves, i.e. one group of leaves with front sides only and the other with back sides only, it was supposed in case of the broadleaf trees that the removal of airborne soot particles of submicron and ultrafine sizes could be affected by the surface roughness of tree leaves, i.e. the veins and other structures on the leaves.

  20. Eutrophication control and the fallacy of nitrogen removal

    SciTech Connect

    Sincero, A.P.

    1984-11-01

    There has been a great deal of controversy over the issue of nitrogen control from sewage treatment plants discharges to alleviate excessive algae growths in receiving bodies of water. Some of the controversy seems to have risen from a thorough misunderstanding of the microbiology involved in the utilization of nitrogen by microbes. In a haste to control eutrophication, some regulators have required the removal of nitrogen from the effluent of sewage treatment plants; e.g., the Patuxent Nitrogen Removal Policy of the State of Maryland.

  1. Particle-bound metal transport after removal of a small dam in the Pawtuxet River, Rhode Island, USA.

    PubMed

    Katz, David R; Cantwell, Mark G; Sullivan, Julia C; Perron, Monique M; Burgess, Robert M; Ho, Kay T

    2016-10-06

    The Pawtuxet River in Rhode Island, USA, has a long history of industrial activity and pollutant discharges. Metal contamination of the river sediments is well documented and historically exceeded toxicity thresholds for a variety of organisms. The Pawtuxet River dam, a low-head dam at the mouth of the river, was removed in August 2011. The removal of the dam was part of an effort to restore the riverine ecosystem after centuries of anthropogenic impact. Sediment traps were deployed below the dam to assess changes in metal concentrations and fluxes (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) from the river system into Pawtuxet Cove. Sediment traps were deployed for an average duration of 24 days each, and deployments continued for 15 months after the dam was removed. Metal concentrations in the trapped suspended particulate matter dropped after dam removal (e.g., 460 to 276 mg/kg for Zn) and remained below preremoval levels for most of the study. However, particle-bound metal fluxes increased immediately after dam removal (e.g., 1206 to 4248 g/day for Zn). Changes in flux rates during the study period indicated that river volumetric flow rates acted as the primary mechanism controlling the flux of metals into Pawtuxet Cove and ultimately upper Narragansett Bay. Even though suspended particulate matter metal concentrations initially dropped after removal of the dam, no discernable effect on the concentration or flux of the study metals exiting the river could be associated with removal of the Pawtuxet River dam. Integr Environ Assess Manag 2016;00:000-000. Published 2016. This article is a US Government work and is in the public domain in the USA.

  2. Evaluation on simultaneous removal of particles and off-flavors using population balance for application of powdered activated carbon in dissolved air flotation process.

    PubMed

    Kwak, D H; Yoo, S J; Lee, E J; Lee, J W

    2010-01-01

    Most of the water treatment plants applying the DAF process are faced with off-flavors control problems. For simultaneous control of particles of impurities and dissolved organics that cause pungent taste and odor in water, an effective method would be the simple application of powdered activated carbon (PAC) in the DAF process. A series of experiments were carried out to explore the feasibility for simultaneous removal of kaolin particles and organic compounds that produce off-flavors (2-MIB and geosmin). In addition, the flotation efficiency of kaolin and PAC particles adsorbing organics in the DAF process was evaluated by employing the population balance theory. The removal efficiency of 2-MIB and geosmin under the treatment condition with kaolin particles for simultaneous treatment was lower than that of the individual treatment. The decrease in the removal efficiency was probably caused by 2-MIB and geosmin remaining in the PAC particle in the treated water of DAF after bubble flotation. Simulation results obtained by the population balance model indicate, that the initial collision-attachment efficiency of PAC particles was lower than that of kaolin particles.

  3. Laser Interaction with Nano-Spheres: Applications in Sub-Micron Particles Removal and Nanodot Array Fabrication

    NASA Astrophysics Data System (ADS)

    Sentis, M.; Grojo, D.; Delaporte, Ph.; Pereira, A.

    Laser-assisted nanoparticle removal processes like selective particle ablation, mechanical ejection, local substrate ablation, explosive evaporation are considered by experimental and theoretical approaches. Experiments are based on the estimation of particle removal efficiencies and thresholds depending on material and size of particles. Afterwards, a novel and efficient photonic-based method to synthesize porous alumina membranes (PAMs) and subsequent metal nano-dot arrays on various substrates, based on near laser field enhancement by nano spheres, is reported.

  4. Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

    PubMed

    Stephens, B; Siegel, J A

    2013-12-01

    This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size.

  5. Aerobic exercise increases phosphate removal during hemodialysis: a controlled trial.

    PubMed

    Orcy, Rafael; Antunes, Maria Fernanda; Schiller, Tamires; Seus, Thamires; Böhlke, Maristela

    2014-04-01

    Previous studies have suggested that exercise during hemodialysis (HD) could increase the efficacy of solute removal, although this hypothesis has not been conclusively evaluated. The goal of this study was to compare the removal of low-molecular weight solutes between HD sessions, with and without aerobic exercise. It was a controlled clinical trial, including HD patients in a randomly cross-over design, such that each patient received a HD session with exercise (intervention) and the next one without exercise (control), three times each. In the exercise sessions, patients pedaled on a cycle ergometer for 60 minutes. The total mass of removed urea, potassium, creatinine, and phosphate were calculated from the solutes concentration in dialysate (continuous spent sampling of dialysate). This was evaluated in a total of 132 HD sessions of patients with a mean age of 54 ± 15 years, 75% male and HD vintage of 3 (2-13) years. Phosphate removal in dialysate during intervention sessions was significantly higher (5.6 [2.5-18.9] vs. 5.1 [1.5-11.2] mg/min) than during control sessions, P = 0.04. The median mass of phosphate removed during control HD session was 1226 (367.8-2697.2) vs. 1348.6 (613.0-4536.2) mg/session during intervention sessions. The exercise did not modify the removal of urea (control 122.6 [61.3-286.0] vs. exercise 112.4 [51.1-250.3] mg/min, P = 0.44), creatinine (control 5.6 [2.5-13.8] vs. exercise 5.6 [2.5-12.8] mg/min, P = 0.49), or potassium (control 13.3 [11.2-15.8] vs. exercise 13.8 [6.6-15.8] mEq/min, P = 0.49). Aerobic exercise during HD increases the efficacy of phosphate removal, without changing urea, creatinine and potassium removal. The implications of this finding in mineral and bone disease and cardiovascular disease need to be evaluated on future clinical trials.

  6. Multi-scale comparison of the fine particle removal capacity of urban forests and wetlands

    PubMed Central

    Zhang, Zhenming; Liu, Jiakai; Wu, Yanan; Yan, Guoxin; Zhu, Lijuan; Yu, Xinxiao

    2017-01-01

    As fine particle (FP) pollution is harmful to humans, previous studies have focused on the mechanisms of FP removal by forests. The current study aims to compare the FP removal capacities of urban forests and wetlands on the leaf, canopy, and landscape scales. Water washing and scanning electron microscopy are used to calculate particle accumulation on leaves, and models are used to estimate vegetation collection, sedimentation, and dry deposition. Results showed that, on the leaf scale, forest species are able to accumulate more FP on their leaf surface than aquatic species in wetlands. On the canopy scale, horizontal vegetation collection is the major process involved in FP removal, and the contribution of vertical sedimentation/emission can be ignored. Coniferous tree species also showed stronger FP collection ability than broadleaf species. In the landscape scale, deposition on the forest occurs to a greater extent than that on wetlands, and dry deposition is the major process of FP removal on rain-free days. In conclusion, when planning an urban green system, planting an urban forest should be the first option for FP mitigation. PMID:28393900

  7. Control of respirable particles and radon progeny with portable air cleaners

    SciTech Connect

    Offermann, F.J.; Sextro, R.G.; Fisk, W.J.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.L.; Yater, J.

    1984-02-01

    Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles and radon progeny. Following injection of cigarette smoke and radon in a room-size chamber, decay rates for particles and radon progeny concentrations were measured with and without air cleaner operation. Particle concentrations were obtained for total number concentration and for number concentration by particle size. In tests with no air cleaner the natural decay rate for cigarette smoke was observed to be 0.2 hr/sup -1/. Air cleaning rates for particles were found to be negligible for several small panel-filters, a residential ion-generator, and a pair of mixing fans. The electrostatic precipitators and extended surface filters tested had significant particle removal rates, and a HEPA-type filter was the most efficient air cleaner. The evaluation of radon progeny control produced similar results; the air cleaners which were effective in removing particles were also effective in removing radon progeny. At low particle concentrations plateout of the unattached radon progeny is an important removal mechanism. Based on data from these tests, the plateout rate for unattached progeny was found to be 15 hr/sup -1/. The unattached fraction and the overall removal rate due to deposition of attached and unattached nuclides have been estimated for each radon decay product as a function of particle concentration. While air cleaning can be effective in reducing total radon progeny, concentrations of unattached radon progeny can increase with increasing air cleaning. 39 references, 26 figures, 9 tables.

  8. Optimization and evaluation of fluorescent tracers for flare removal in gas-phase particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Chennaoui, M.; Angarita-Jaimes, D.; Ormsby, M. P.; Angarita-Jaimes, N.; McGhee, E.; Towers, C. E.; Jones, A. C.; Towers, D. P.

    2008-11-01

    We report the development of optimized fluorescent dye-doped tracer particles for gas-phase particle image velocimetry (PIV) and their use to eliminate 'flare' from the images obtained. In such applications, micron-sized tracer particles are normally required to accurately follow the flow. However, as the tracer size is reduced the amount of light incident on the particle diminishes and consequently the intensity of emitted light (fluorescence). Hence, there is a requirement to identify dyes with high quantum yield that can be dissolved in conventional tracer media at high concentrations. We describe the selection and characterization of a highly fluorescent blue-emitting dye, Bis-MSB, using a novel method, employing stabilized micro-emulsions, to emulate the fluorescence properties of tracer particles. We present the results of PIV experiments, using 1 µm tracer particles of o-xylene doped with Bis-MSB, in which elastically scattered 'flare' has been successfully removed from the images using an appropriate optical filter.

  9. Monodisperse Block Copolymer Particles with Controllable Size, Shape, and Nanostructure

    NASA Astrophysics Data System (ADS)

    Shin, Jae Man; Kim, Yongjoo; Kim, Bumjoon; PNEL Team

    Shape-anisotropic particles are important class of novel colloidal building block for their functionality is more strongly governed by their shape, size and nanostructure compared to conventional spherical particles. Recently, facile strategy for producing non-spherical polymeric particles by interfacial engineering received significant attention. However, achieving uniform size distribution of particles together with controlled shape and nanostructure has not been achieved. Here, we introduce versatile system for producing monodisperse BCP particles with controlled size, shape and morphology. Polystyrene-b-polybutadiene (PS-b-PB) self-assembled to either onion-like or striped ellipsoid particle, where final structure is governed by amount of adsorbed sodium dodecyl sulfate (SDS) surfactant at the particle/surrounding interface. Further control of molecular weight and particle size enabled fine-tuning of aspect ratio of ellipsoid particle. Underlying physics of free energy for morphology formation and entropic penalty associated with bending BCP chains strongly affects particle structure and specification.

  10. Absorption removal of sulfur dioxide by falling water droplets in the presence of inert solid particles

    NASA Astrophysics Data System (ADS)

    Liu, I.-Hung; Chang, Ching-Yuan; Liu, Su-Chin; Chang, I.-Cheng; Shih, Shin-Min

    An experimental analysis of the absorption removal of sulfur dioxide by the free falling water droplets containing the inert solid particles is presented. The wheat flour powder is introduced as the inert solid particles. Tests with and without the flour powder in the water droplets are examined. The mass fluxes and mass transfer coefficients of SO 2 for the cases with and without the flour powder are compared to elucidate the effects of the inert solid particles contained in the water droplets on the gas absorption. The results indicate aignificant difference between the two cases for the concentrations of the flour powder in the absorbent droplets ( Cs) within the ranges of the experimental conditions, namely 0.1 to 10 wt% flour powder in the absorbent droplets. In general, the inert solid particles of the flour powder as the impurities in the water droplets tend to decrease the SO 2 absorption rate for the experimental absorption system under investigation. Various values of Cs cause various levels of the interfacial resistance and affect the gas absorption rate. The interfacial resistance is recognized by introducing an interfacial mass transfer coefficient ks with its reciprocal being proportional to the magnitude of the interfacial resistance. The values of 1/ ks may be computed by the use of the equation 1/ ks=(1/ KOLs-1/ KOL), where KOLs and KOL are the overall liquid-phase mass transfer coefficients with and without the inert solid particles, respectively. The values of ks with Cs of 0.1 to 10 wt% are about 0.295-0.032 cms -1 for absorbing 1000-3000 ppmv SO 2 with the water droplets. This kind of information is useful for the SO 2 removal and the information of acid rain that the impurities of the inert solid particles contaminate the water droplets.

  11. NOM removal by adsorption and membrane filtration using heated aluminum oxide particles.

    PubMed

    Cai, Zhenxiao; Kim, Jaeshin; Benjamin, Mark M

    2008-01-15

    Heated aluminum oxide particles (HAOPs) are a newly synthesized adsorbent with attractive properties for use in hybrid adsorption/membrane filtration systems. This study compared removal of natural organic matter (NOM) from water by adsorption onto HAOPs with that by adsorption onto powdered activated carbon (PAC) or coagulation with alum or ferric chloride (FeCl3); explored the overlap between the NOM molecules that preferentially adsorb to HAOPs and those that are removed by the more conventional approaches; and evaluated NOM removal and fouling in hybrid adsorbent/membrane systems. For equivalent molar doses of the trivalent metals, HAOPs remove more NOM, and NOM with higher SUVA254, than alum or FeCl3. Most of the HAOPs-nonadsorbable fraction of the NOM can be adsorbed by PAC; in fact, that fraction appears to be preferentially adsorbed compared to the average NOM in untreated water. Predeposition of the adsorbents on a microfiltration membrane improves system performance. For the water tested, at a flux of 100 L/m2-hr, predeposition of 11 mg/L PAC and 5 mg/L HAOPs (as Al3+) allowed the system to operate 5 times as long before the transmembrane pressure increased by 1 psi and to remove 10-20 times as much NOM as when no adsorbents were added.

  12. Planck 2013 results. X. HFI energetic particle effects: characterization, removal, and simulation

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dupac, X.; Efstathiou, G.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Girard, D.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J.-M.; Lasenby, A.; Laureijs, R. J.; Lawrence, C. R.; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Miniussi, A.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Racine, B.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rusholme, B.; Sanselme, L.; Santos, D.; Sauvé, A.; Savini, G.; Scott, D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    We describe the detection, interpretation, and removal of the signal resulting from interactions of high energy particles with the Planck High Frequency Instrument (HFI). There are two types of interactions: heating of the 0.1 K bolometer plate; and glitches in each detector time stream. The transientresponses to detector glitch shapes are not simple single-pole exponential decays and fall into three families. The glitch shape for each family has been characterized empirically in flight data and these shapes have been used to remove glitches from the detector time streams. The spectrum of the count rate per unit energy is computed for each family and a correspondence is made to the location on the detector of the particle hit. Most of the detected glitches are from Galactic protons incident on the die frame supporting the micro-machined bolometric detectors. In the Planck orbit at L2, the particle flux is around 5 cm-2 s-1 and is dominated by protons incident on the spacecraft with energy >39 MeV, at a rate of typically one event per second per detector. Different categories of glitches have different signatures in the time stream. Two of the glitch types have a low amplitude component that decays over nearly 1 s. This component produces excess noise if not properly removed from the time-ordered data. We have used a glitch detection and subtraction method based on the joint fit of population templates. The application of this novel glitch subtraction method removes excess noise from the time streams. Using realistic simulations, we find that this method does not introduce signal bias into the Planck data.

  13. Particle count monitoring of reverse osmosis water treatment for removal of low-level radionuclides

    SciTech Connect

    Moritz, E.J.; Hoffman, C.R.; Hergert, T.R.

    1995-03-01

    Laser diode particle counting technology and analytical measurements were used to evaluate a pilot-scale reverse osmosis (RO) water treatment system for removal of particulate matter and sub-picocurie low-level radionuclides. Stormwater mixed with Waste Water Treatment Plant (WWTP) effluent from the Rocky Flats Environmental Technology Site (RFETS), formerly a Department of Energy (DOE) nuclear weapons production facility, were treated. No chemical pretreatment of the water was utilized during this study. The treatment system was staged as follows: multimedia filtration, granular activated carbon adsorption, hollow tube ultrafiltration, and reverse osmosis membrane filtration. Various recovery rates and two RO membrane models were tested. Analytical measurements included total suspended solids (TSS), total dissolved solids (TDS), gross alpha ({alpha}) and gross beta ({beta}) activity, uranium isotopes {sup 233/234}U and {sup 238}U, plutonium {sup 239/240}Pu, and americium {sup 241}Am. Particle measurement between 1--150 microns ({mu}) included differential particle counts (DPC), and total particle counts (TPC) before and after treatment at various sampling points throughout the test. Performance testing showed this treatment system produced a high quality effluent in clarity and purity. Compared to raw water levels, TSS was reduced to below detection of 5 milligrams per liter (mg/L) and TDS reduced by 98%. Gross {alpha} was essentially removed 100%, and gross {beta} was reduced an average of 94%. Uranium activity was reduced by 99%. TPC between 1-150{mu} were reduced by an average 99.8% to less than 1,000 counts per milliliter (mL), similar in purity to a good drinking water treatment plant. Raw water levels of {sup 239/240}Pu and {sup 241}Am were below reliable quantitation limits and thus no removal efficiencies could be determined for these species.

  14. Removal of Microcystis aeruginosa using nano-Fe3O4 particles as a coagulant aid.

    PubMed

    Zhang, Bo; Jiang, Dan; Guo, Xiaochen; He, Yiliang; Ong, Choon Nam; Xu, Yongpeng; Pal, Amrita

    2015-12-01

    Blue-green algae bloom is of great concern globally since they adversely affect the water ecosystem and also drinking water treatment processes. This work investigated the removal of Microcystis aeruginosa (M. aeruginosa) by combining the conventional coagulant polyaluminum chloride (PACl) with nano-Fe3O4 particles as a coagulant aid. The results showed that the addition of nano-Fe3O4 significantly improved the removal efficiency of M. aeruginosa by reducing the amount of PACl dosage and simultaneously hastening the sedimentation. At the M. aeruginosa density of an order of magnitude of 10(7), 10(6), and 10(5) pcs/mL, respectively, the corresponding PACl dose of 200, 20, and 2 mg/L and the mass ratio of PACl to nano-Fe3O4 of 4:1, the removal efficiency of M. aeruginosa could be increased by 33.0, 44.7, and 173.1%, respectively. Compared to PACl, PACl combined with the nano-Fe3O4 as a coagulant aid had higher removal efficiency at a wider pH range. SEM images showed that nano-Fe3O4 first combined with PACl to form clusters and further generated the flocs with algae. Results from the laser particle analyzer further suggested that the floc size increased with the addition of nano-Fe3O4. It was noted that the addition of nano-Fe3O4 led to aluminum species change after PACl hydrolyzed in the algae solution, from Ala to Alb and Alc subsequently. As a coagulant aid, the nano-Fe3O4, in conjunction with PACl, apparently provided nucleation sites for larger flocs to integrate with M. aeruginosa. In addition, increased floc density improved the removal of M. aeruginosa.

  15. A facile approach towards amino-coated polyethersulfone particles for the removal of toxins.

    PubMed

    Song, Xin; Wang, Rui; Zhao, Weifeng; Sun, Shudong; Zhao, Changsheng

    2017-01-01

    The removal of toxins is important due to the damage to aquatic environment. In this work, a facile and green approach based on mussel-inspired coatings was used to fabricate amino-coated particles via the reaction between amine and catechol, using hexanediamine as the representative amine. The particles were characterized by Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). The particles showed selective adsorption capability to Congo red (CR) and the adsorption process fitted the pseudo-second-order model, the intraparticle diffusion model, the Langmuir isotherm, the Freundlich isotherm and the Sips isotherm well. Furthermore, this approach was verified to have applicability to various amines such as diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA), and the amino-coated particles exhibited diverse adsorption capacities to CR, Cu(2+) and bilirubin. Considering that the approach is easy to operate and the whole preparation process is in an aqueous solution, it is believed that the facile, green and economical approach has great potential to prepare particles for wastewater treatment.

  16. Methodologies for Removing/Desorbing and Transporting Particles from Surfaces to Instrumentation

    NASA Astrophysics Data System (ADS)

    Miller, Carla J.; Cespedes, Ernesto R.

    2012-12-01

    Explosive trace detection (ETD) continues to be a key technology supporting the fight against terrorist bombing threats. Very selective and sensitive ETD instruments have been developed to detect explosive threats concealed on personnel, in vehicles, in luggage, and in cargo containers, as well as for forensic analysis (e.g. post blast inspection, bomb-maker identification, etc.) in a broad range of homeland security, law enforcement, and military applications. A number of recent studies have highlighted the fact that significant improvements in ETD systems' capabilities will be achieved, not by increasing the selectivity/sensitivity of the sensors, but by improved techniques for particle/vapor sampling, pre-concentration, and transport to the sensors. This review article represents a compilation of studies focused on characterizing the adhesive properties of explosive particles, the methodologies for removing/desorbing these particles from a range of surfaces, and approaches for transporting them to the instrument. The objectives of this review are to summarize fundamental work in explosive particle characterization, to describe experimental work performed in harvesting and transport of these particles, and to highlight those approaches that indicate high potential for improving ETD capabilities.

  17. Hexavalent chromium removal from near natural water by copper-iron bimetallic particles.

    PubMed

    Hu, Ching-Yao; Lo, Shang-Lien; Liou, Ya-Hsuan; Hsu, Ya-Wen; Shih, Kaimin; Lin, Chin-Jung

    2010-05-01

    The reduction of hexavalent chromium (Cr(VI)) by zero-valent iron (ZVI) is self-inhibiting in near natural groundwater because insulating Fe(III)-Cr(III) (oxy)hydroxide film forms on the ZVI surface during the reaction. This study tries to overcome this deficiency by coating the surface of ZVI with copper to form copper-iron bimetallic particles. The Cr(VI) removal rate by ZVI rose significantly after the copper coating was applied. The copper loading needed for enhancing Cr(VI) removal was much higher than that needed for enhancing removal of chlorinated organic compounds or other oxidative contaminants, because of the higher oxidation potential of Cr(VI). The results of X-ray photoelectron spectroscopy (XPS) indicate that coating copper onto the surface of ZVI can not only increase the deepness of the oxidation film but also increase the oxidation state of iron in the film. This phenomenon means higher Cr(VI) removal capacity per unit weight of ZVI.

  18. Tribology and Removal Rate Characteristics of Chemical Mechanical Planarization Pads Containing Water Soluble Particles

    NASA Astrophysics Data System (ADS)

    Charns, L.; Philipossian, A.

    2006-07-01

    Novel non-porous pads incorporating different amounts of embedded water soluble particles (WSP) have been characterized and compared to a conventional porous pad for interlayer dielectric (ILD) chemical mechanical planarization (CMP) applications. Removal rate results indicated that polishing with WSP pads was Prestonian in nature (similar to conventional porous pads). A decrease in removal rate at high combinations of pressure and velocity was observed during in-situ conditioning with WSP pads. This anomalous behavior was most likely due to the alternatively feeding and starving the wafer of slurry during in-situ conditioning since doubling the flow rate resolved the problem. The anomalous behavior, however, was not observed when conditioning was performed ex-situ. Frictional analysis indicated that polishing with WSP pads proceeded via boundary lubrication like the other porous pads with concentrically grooved surface geometries.

  19. Particle scale modeling of material removal and surface roughness in chemical mechanical polishing

    NASA Astrophysics Data System (ADS)

    Yeruva, Suresh Babu

    2005-11-01

    Chemical mechanical polishing (CMP) is widely adopted in producing excellent local and global planarization of microelectronic devices. It has been demonstrated experimentally that the polishing performance is a result of the synergistic effect of both the chemicals and the particles involved in CMP. However, the fundamental mechanisms of material removal and the interactions of the chemical and mechanical effects are not well understood. A comprehensive model for CMP was developed taking into account both the chemical and mechanical effects for slurries with a given particle size distribution. The model developed (PERC II) is based on a previously developed model (PERC I). The chemical aspect is attributed to the chemical modification of the surface layer due to slurry chemistry, whereas the mechanical aspect is incorporated by indentation of particles into the modified layer and the substrate depending on the operating conditions. In this study, the effects of particle size and pad asperity distributions are included in the model. The contact area of pad with wafer was measured in dry and wet conditions in different pH solutions using optical microscopy and Fourier transform infrared spectroscopy respectively. Pad surface mechanical properties in dry and wet states were also investigated using atomic force microscopy. The contact area results obtained were utilized in modeling to estimate the pad modulus leading to pad-wafer contact stress distribution. The predictions of the model show a reasonable agreement with the experimental data. The model is validated for oxide and metal CMP systems. The PERC II model not only predicts the overall removal rate, but also the surface roughness of the polished wafer in selected systems. The developed model can be used to optimize the current CMP systems and provide insights into future CMP endeavors.

  20. Hollow latex particles functionalized with chitosan for the removal of formaldehyde from indoor air.

    PubMed

    Nuasaen, Sukanya; Opaprakasit, Pakorn; Tangboriboonrat, Pramuan

    2014-01-30

    Chitosan and polyethyleneimine (PEI) functionalized hollow latex (HL) particles were conveniently fabricated by coating poly(methyl methacrylate-co-divinyl benzene-co-acrylic acid) (P(MMA/DVB/AA)) HL particles with 5 wt% chitosan or 14 wt% PEI. The materials were used as formaldehyde adsorbent, where their adsorbent activity was examined by Fourier Transform Infrared (FTIR) spectroscopy. The nucleophilic addition of amines to carbonyls generated a carbinolamine intermediate with a characteristic band at 1,020 cm(-1) and Schiff base product at 1650 cm(-1), whose intensity increased with prolonged formaldehyde exposure times. The major products observed in HL-chitosan were carbinolamine and Schiff base, whereas a small amount of Schiff base was obtained in HL-PEI particles, confirming a chemical bond formation without re-emission of formaldehyde. Compared to HL-PEI, HL-chitosan possesses higher formaldehyde adsorption efficiency. Besides providing opacity and whiteness, the multilayer HL-chitosan particles can effectively remove indoor air pollutants, i.e., formaldehyde gas, and, hence, would be useful in special coating applications.

  1. Dielectrophoretic sample preparation for environmental monitoring of microorganisms: Soil particle removal.

    PubMed

    Fatoyinbo, Henry O; McDonnell, Martin C; Hughes, Michael P

    2014-07-01

    Detection of pathogens from environmental samples is often hampered by sensors interacting with environmental particles such as soot, pollen, or environmental dust such as soil or clay. These particles may be of similar size to the target bacterium, preventing removal by filtration, but may non-specifically bind to sensor surfaces, fouling them and causing artefactual results. In this paper, we report the selective manipulation of soil particles using an AC electrokinetic microfluidic system. Four heterogeneous soil samples (smectic clay, kaolinitic clay, peaty loam, and sandy loam) were characterised using dielectrophoresis to identify the electrical difference to a target organism. A flow-cell device was then constructed to evaluate dielectrophoretic separation of bacteria and clay in a continous flow through mode. The average separation efficiency of the system across all soil types was found to be 68.7% with a maximal separation efficiency for kaolinitic clay at 87.6%. This represents the first attempt to separate soil particles from bacteria using dielectrophoresis and indicate that the technique shows significant promise; with appropriate system optimisation, we believe that this preliminary study represents an opportunity to develop a simple yet highly effective sample processing system.

  2. Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and burrows pond rearing system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal eff...

  3. Transparent exopolymer particles (TEP) removal efficiency by a combination of coagulation and ultrafiltration to minimize SWRO membrane fouling.

    PubMed

    Li, Sheng; Lee, Shang-Tse; Sinha, Shahnawaz; Leiknes, TorOve; Amy, Gary L; Ghaffour, Noreddine

    2016-10-01

    This study investigated the impact of coagulation on the transformation between colloidal and particulate transparent exopolymer particles (TEP) in seawater; and the effectiveness of a combined pretreatment consisting of coagulation and UF on minimizing TEP fouling of seawater reverse osmosis (SWRO) membranes. Coagulation with ferric chloride at pH 5 substantially transformed colloidal TEP (0.1-0.4) into particulate TEP (>0.4) leading to a better membrane fouling control. Both 50 and 100 kDa molecular weight cut-off (MWCO) UF membranes removed most of particulate and colloidal TEP without the assistance of coagulation, but coagulation is still necessary for better UF fouling control. The improvement of combined SWRO pretreatment with coagulation and 50 kDa UF membranes was not that much significant compared to UF pretreatment with 50 KDa alone. Therefore, the minimal coagulant dosage for seawater containing TEP should be based on the UF fouling control requirements rather than removal efficiency.

  4. One active debris removal control system design and error analysis

    NASA Astrophysics Data System (ADS)

    Wang, Weilin; Chen, Lei; Li, Kebo; Lei, Yongjun

    2016-11-01

    The increasing expansion of debris presents a significant challenge to space safety and sustainability. To address it, active debris removal, usually involving a chaser performing autonomous rendezvous with targeted debris to be removed is a feasible solution. In this paper, we explore a mid-range autonomous rendezvous control system based on augmented proportional navigation (APN), establishing a three-dimensional kinematic equation set constructed in a rotating coordinate system. In APN, feedback control is applied in the direction of line of sight (LOS), thus analytical solutions of LOS rate and relative motion are expectedly obtained. To evaluate the effectiveness of the control system, we adopt Zero-Effort-Miss (ZEM) in this research as the index, the uncertainty of which is directly determined by that of LOS rate. Accordingly, we apply covariance analysis (CA) method to analyze the propagation of LOS rate uncertainty. Consequently, we find that the accuracy of the control system can be verified even with uncertainty and the CA method is drastically more computationally efficient compared with nonlinear Monte-Carlo method. Additionally, to justify the superiority of the system, we further discuss more simulation cases to show the robustness and feasibility of APN proposed in the paper.

  5. Preparation, characterization, and phosphate removal and recovery of magnetic MnFe2O4 nano-particles as adsorbents.

    PubMed

    Xia, Shumei; Xu, Xiaoming; Xu, Changsong; Wang, Hongshuai; Zhang, Xiaowei; Liu, Guangmin

    2016-01-01

    Phosphate removal is an important method for controlling eutrophication in bodies of water. Adsorption is an effective phosphate removal approach. In this research, the adsorbent, namely, MnFe2O4, was prepared through the improved co-precipitation method and investigated in terms of phosphate removal. MnFe2O4 was characterized by scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and Fourier transform infrared spectroscopy. Phosphate adsorption by MnFe2O4, desorption of adsorbed MnFe2O4 with the regeneration of desorbed MnFe2O4, and phosphate recovery were researched. Experimental results showed that adding the appropriate amount of polyethylene glycol to MnFe2O4 precursors during preparation inhibited the agglomeration of MnFe2O4 between particles because of the magnetic property of MnFe2O4 etc. High crystallinity and strong magnetism were achieved by MnFe2O4 at low temperatures. Average particle size was 5.1 nm. The hysteresis loops confirmed the ferrimagnetic behaviour of MnFe2O4 with a high saturation magnetization (i.e. 26.27 emu/g). The adsorption mechanism of phosphate was mainly physical. The prepared MnFe2O4 had a spinel structure. The proposed technique achieved a phosphate removal rate of 96.06%. A considerable amount of phosphate was desorbed from the adsorbed MnFe2O4 in 15 w/v% NaOH solution. The adsorption capacity of the desorbed MnFe2O4 could be restored to 96.73% in 10 w/v% NaNO3 solution through ion exchange. A sustainable phosphate source was recovered via hydroxyapatite crystallization in the desorption solution, which contained an abundant amount of phosphate as seed for suitable recovery condition. This finding suggested that MnFe2O4 could be a promising adsorbent for efficient phosphate removal.

  6. Investigation of high velocity separator for particle removal in coal gasification plants. Phase II report

    SciTech Connect

    Linhardt, H.D.

    1980-01-15

    This report summarizes the results of Phase II of the High Velocity Particle Separator Program performed under Contract EF-77-C-01-2709. This high velocity wedge separator has the potential to reduce equipment size and cost of high temperature and pressurized particulate removal equipment for coal derived gases. Phase II has been directed toward testing and detailed conceptual design of an element suitable for a commercial scale high temperature, high pressure particle separator (HTPS). Concurrently, Phase IA has been conducted, which utilized the ambient analog method (AAM) for aerodynamic and collection performance investigation of each HTPS configuration prior and during hot testing. This report summarizes the results of Phase IA and II. The AAM effort established correlation of theoretical analysis and experiment for HTPS pressure drop, purge flow ratio and collection efficiency potential. Task I defined the initial test conditions to be the contract design point of 1800/sup 0/F and 350 psia. The 1800/sup 0/F, 350 psia testing represents the main high temperature testing with coal-derived particulates in the 2 to 10 micron range. Phase IA and Phase II have demonstrated efficient particle collection with acceptable pressure drop. In view of these encouraging results, it is reasonable to apply the developed technology toward future hot gas particulate cleanup requirements.

  7. Fuzzy control of nitrogen removal in predenitrification process using ORP.

    PubMed

    Peng, Y; Ma, Y; Wang, S; Wang, X

    2005-01-01

    In order to meet increasingly stringent discharge standards, new applications and control strategies for the sustainable removal of nitrogen from wastewater have to be implemented. In the past years, numerous studies have been carried out dealing with the application of fuzzy logic to improve the control of the activated sludge process. In this paper, fuzzy control strategies of predenitrification systems are presented that could lead to better effluent quality and, in parallel, to a reduction of chemicals consumption. Extensive experimental investigations on lab scale plant studies have shown that there was excellent correlation between nitrate concentration and ORP value at the end of the anoxic zone. Results indicated that ORP could be used as an on-line fuzzy control parameter of nitrate recirculation and external carbon addition. The optimal value of ORP to control nitrate recirculation and external carbon addition was - 86 +/- 2 mV and - 90 +/- 2 mV, respectively. The results obtained with real wastewater also showed the good performance and stability of the fuzzy controllers independently from external disturbances. The integrated control structure of nitrate recirculation and external carbon addition in the predenitrification system is also presented.

  8. Layered reactive particles with controlled geometries, energies, and reactivities, and methods for making the same

    DOEpatents

    Fritz, Gregory M.; Weihs, Timothy P.; Grzyb, Justin A.

    2016-07-05

    An energetic composite having a plurality of reactive particles each having a reactive multilayer construction formed by successively depositing reactive layers on a rod-shaped substrate having a longitudinal axis, dividing the reactive-layer-deposited rod-shaped substrate into a plurality of substantially uniform longitudinal segments, and removing the rod-shaped substrate from the longitudinal segments, so that the reactive particles have a controlled, substantially uniform, cylindrically curved or otherwise rod-contoured geometry which facilitates handling and improves its packing fraction, while the reactant multilayer construction controls the stability, reactivity and energy density of the energetic composite.

  9. Layered reactive particles with controlled geometries, energies, and reactivities, and methods for making the same

    SciTech Connect

    Fritz, Gregory M; Knepper, Robert Allen; Weihs, Timothy P; Gash, Alexander E; Sze, John S

    2013-04-30

    An energetic composite having a plurality of reactive particles each having a reactive multilayer construction formed by successively depositing reactive layers on a rod-shaped substrate having a longitudinal axis, dividing the reactive-layer-deposited rod-shaped substrate into a plurality of substantially uniform longitudinal segments, and removing the rod-shaped substrate from the longitudinal segments, so that the reactive particles have a controlled, substantially uniform, cylindrically curved or otherwise rod-contoured geometry which facilitates handling and improves its packing fraction, while the reactant multilayer construction controls the stability, reactivity and energy density of the energetic composite.

  10. Method and apparatus for removing coarse unentrained char particles from the second stage of a two-stage coal gasifier

    DOEpatents

    Donath, Ernest E.

    1976-01-01

    A method and apparatus for removing oversized, unentrained char particles from a two-stage coal gasification process so as to prevent clogging or plugging of the communicating passage between the two gasification stages. In the first stage of the process, recycled process char passes upwardly while reacting with steam and oxygen to yield a first stage synthesis gas containing hydrogen and oxides of carbon. In the second stage, the synthesis gas passes upwardly with coal and steam which react to yield partially gasified char entrained in a second stage product gas containing methane, hydrogen, and oxides of carbon. Agglomerated char particles, which result from caking coal particles in the second stage and are too heavy to be entrained in the second stage product gas, are removed through an outlet in the bottom of the second stage, the particles being separated from smaller char particles by a counter-current of steam injected into the outlet.

  11. Selective removal of 17β-estradiol with molecularly imprinted particle-embedded cryogel systems.

    PubMed

    Koç, İlker; Baydemir, Gözde; Bayram, Engin; Yavuz, Handan; Denizli, Adil

    2011-09-15

    The selective removal of 17β-estradiol (E2) was investigated by using molecularly E2 imprinted (MIP) particle embedded poly(hydroxyethyl methacrylate) (PHEMA) cryogel. PHEMA/MIP composite cryogel was characterized by FTIR, SEM, swelling studies, and surface area measurements. E2 adsorption studies were performed by using aqueous solutions which contain various amounts of E2. The specificity of PHEMA/MIP cryogel to recognition of E2 was performed by using cholesterol and stigmasterol. PHEMA/MIP cryogel exhibited a high binding capacity (5.32 mg/gpolymer) and high selectivity for E2 in the presence of competitive molecules, cholesterol (k(E2/cholesterol) = 7.6) and stigmasterol (k(E2/Stigmasterol) = 85.8). There is no significant decrease in adsorption capacity after several adsorption-desorption cycles.

  12. Electrostatic particle collector with improved features for installing and/or removing its collector plates

    DOEpatents

    Siegfried, Matthew J.; Radford, Daniel R.; Huffman, Russell K.

    2017-04-04

    An electrostatic particle collector may generally include a housing having sidewalls extending lengthwise between a first end and a second end. The housing may define a plate slot that extends heightwise within the housing between a top end and a bottom end. The housing may further include a plate access window that provides access to the bottom end of the plate slot. The collector may also include a collector plate configured to be installed within the plate slot that extends heightwise between a top edge and a bottom edge. Additionally, when the collector plate is installed within the plate slot, the bottom edge of the collector plate may be accessible from an exterior of the housing via the plate access window so as to allow the bottom edge of the collector plate to be moved relative to the housing to facilitate removal of the collector plate from the housing.

  13. A new reactor for denitrification and micro-particle removal in recirculated aquaculture systems.

    PubMed

    Boley, A; Korshun, G; Boley, S; Jung-Schroers, V; Adamek, M; Steinhagen, D; Richter, S

    2017-03-01

    A 'membrane-denitrification' reactor (MDR) was developed and tested in a semi-technical recirculation aquaculture system in comparison to a double - without MDR - as reference system. The MDR consisted of a reactor with an ultrafiltration membrane unit for removal of micro-particles (e.g. sludge flocs, bacteria and parasites). Specific carrier material provided surfaces for biofilm growth in a fluidized bed reactor with ethanol as carbon source for denitrification. The continuous motion of these carriers cleaned the membrane surface. With online and laboratory measurements of water parameters and operational data the feasibility of the concept was verified. An advantage is that no chemicals are needed to clean the membranes. Examinations of the fish and water analyses proved an MDR can positively influence cortisol, as a stress marker, and the microflora of the aquatic system.

  14. Facile synthesis of copper(II)-decorated magnetic particles for selective removal of hemoglobin from blood samples.

    PubMed

    Ding, Chun; Ma, Xiangdong; Yao, Xin; Jia, Li

    2015-12-11

    In this report, the Cu(2+)-immobilized magnetic particles were prepared by a facile route and they were used as adsorbents for removal of high abundance of hemoglobin in blood based on immobilized metal affinity chromatography. Ethylenediaminetetraacetic acid modified magnetic particles (EDTA-Fe3O4) were first synthesized through a one-pot solvothermal method and then charged with copper ions. The as-prepared Cu(2+)-EDTA-Fe3O4 particles were characterized by Fourier transform infrared spectrometry, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometry and zeta potential. Factors affecting the adsorption of bovine hemoglobin on Cu(2+)-EDTA-Fe3O4 particles (including contact time, solution pH, ionic strength and initial concentration of protein) were investigated. The adsorption process followed a pseudo-second-order kinetic model and the adsorption equilibrium could be achieved in 60min. The adsorption isotherm data could be well described by a Langmuir model and the maximum adsorption capacity was 1250mgg(-1). The as-prepared particles showed high efficiency and excellent selectivity for removal of hemoglobin from bovine and human blood. The removal process integrated the selectivity of immobilized metal affinity chromatography and the convenience of magnetic separation. The results demonstrated that Cu(2+)-EDTA-Fe3O4 particles had potential application in removal of abundant histidine-rich proteins in biomedical diagnosis analysis.

  15. The adsorptive removal of disinfection by-product precursors in a high-SUVA water using iron oxide-coated pumice and volcanic slag particles.

    PubMed

    Kaplan Bekaroglu, S S; Yigit, N O; Karanfil, T; Kitis, M

    2010-11-15

    The main objective of this work was to study the effectiveness of iron oxide-coated pumice and volcanic slag particles in removing disinfection by-product (DBP) precursors from a raw drinking water source with high specific UV absorbance (SUVA(254)) value. Iron oxide coating of particles significantly increased dissolved organic carbon (DOC) uptakes and decreased DBP formation after chlorination compared to uncoated particles. pH values close to neutral levels during adsorption and chlorination provided DOC, trihalomethane and haloacetic acid reductions around 60-75% employing 6 g/L coated particle dosage. Higher degree of DOC and DBP reductions (>85%) were obtained with increasing particle dose. The uptake of bromide by iron oxide surfaces was negligible and increasing bromide concentrations (up to 550 μg/L) did not negatively impact the DOC uptake. However, due to competition between natural organic matter (NOM) and bicarbonate for the iron oxide surfaces, increasing bicarbonate alkalinity levels reduced DOC uptakes. Overall, the results indicated that the iron oxide-coated pumice/slag particles are effective adsorbents to remove NOM and control DBP formation in waters with relatively high DOC and SUVA(254) levels. However, they may not be effective for waters with alkalinity levels above 250 mg CaCO(3)/L.

  16. Controlling Charged Particles with Inhomogeneous Electrostatic Fields

    NASA Technical Reports Server (NTRS)

    Herrero, Federico A. (Inventor)

    2016-01-01

    An energy analyzer for a charged-particle spectrometer may include a top deflection plate and a bottom deflection plate. The top and bottom deflection plates may be non-symmetric and configured to generate an inhomogeneous electrostatic field when a voltage is applied to one of the top or bottom deflection plates. In some instances, the top and bottom deflection plates may be L-shaped deflection plates.

  17. Controlled Precipitation of Radiation Belt Particles

    DTIC Science & Technology

    2007-08-23

    in support of the Air Force’s TIPER program, as well AFRL/NRL’s Injected whistler Precipitating HAARP facility in Gakona,waves Electrons Alaska. The...does LEP play in the losses of >100 keV radiation belt particles? (I A II II. Amplitude Data for 28- Mar -2001 47 N A A -LV t 9.." - 9.52" ---(b) -- SA

  18. The removal of uranium onto carbon-supported nanoscale zero-valent iron particles

    NASA Astrophysics Data System (ADS)

    Crane, Richard A.; Scott, Thomas

    2014-12-01

    In the current work carbon-supported nanoscale zero-valent iron particles (CS nZVI), synthesised by the vacuum heat treatment of ferric citrate trihydrate absorbed onto carbon black, have been tested for the removal of uranium (U) from natural and synthetic waters. Two types of CS nZVI were tested, one vacuum annealed at 600 °C for 4 h and the other vacuum annealed at 700 °C for 4 h, with their U removal behaviour compared to nZVI synthesised via the reduction of ferrous iron using sodium borohydride. The batch systems were analysed over a 28-day reaction period during which the liquid and nanoparticulate solids were periodically analysed to determine chemical evolution of the solutions and particulates. Results demonstrate a well-defined difference between the two types of CS nZVI, with greater U removal exhibited by the nanomaterial synthesised at 700 °C. The mechanism has been attributed to the CS nZVI synthesised at 700 °C exhibiting (i) a greater proportion of surface oxide Fe2+ to Fe3+ (0.34 compared to 0.28); (ii) a greater conversion of ferric citrate trihydrate [2Fe(C6H5O7)·H2O] to Fe0; and (iii) a larger surface area (108.67 compared to 88.61 m2 g-1). Lower maximum U uptake was recorded for both types of CS nZVI in comparison with the borohydride-reduced nZVI. A lower decrease in solution Eh and DO was also recorded, indicating that less chemical reduction of U was achieved by the CS nZVI. Despite this, lower U desorption in the latter stages of the experiment (>7 days) was recorded for the CS nZVI synthesised at 700 °C, indicating that carbon black in the CS nZVI is likely to have contributed towards U sorption and retention. Overall, it can be stated that the borohydride-reduced nZVI were significantly more effective than CS nZVI for U removal over relatively short timescales (e.g. <48 h), however, they were more susceptible to U desorption over extended time periods.

  19. Controlled removal of a nonviral episomal vector from transfected cells.

    PubMed

    Rupprecht, Sina; Hagedorn, Claudia; Seruggia, Davide; Magnusson, Terese; Wagner, Ernst; Ogris, Manfred; Lipps, Hans J

    2010-10-15

    An ideal vector to be used in gene therapy should allow long-term and regulated expression of the therapeutic sequence, but in many cases, it would be most desirable to remove all ectopic vector sequences from the cell once expression is no longer required. The vector pEPI is the first nonviral autonomous replicon that was constructed for mammalian cells. It represents a minimal model system to study the epigenetic regulation of replication and transcription but is also regarded as a promising alternative to currently used viral vector systems in gene therapy. Its function relies on a transcription unit linked to an S/MAR sequence. We constructed an inducible pEPI vector system based on the Tet ON system in which transcription is switched on in the presence of doxycycline. We show that for vector replication and long-term maintenance an ongoing transcription running into the S/MAR element is required. Once established, the vector is lost from the cell upon switching off transcription from the gene linked to the S/MAR. This feature provides not only controlled transgene expression but also the possibility to remove all vector molecules from the cells upon demand. This inducible episomal nonviral vector system will find broad application in gene therapy but also in reprogramming of somatic cells or modification of stem cells.

  20. Effects of surface charge, micro-bubble size and particle size on removal efficiency of electro-flotation.

    PubMed

    Han, M Y; Kim, M K; Ahn, H J

    2006-01-01

    Flotation is a water treatment alternative to sedimentation, and uses small bubbles to remove low-density particles from potable water and wastewater. The effect of zeta potential, bubble size and particle size on removal efficiency of the electro-flotation process was investigated because previous model-simulations indicated that these attributes are critical for high collision efficiency between micro-bubbles and particles. Solutions containing Al3+ as the metal ion were subjected to various conditions. The zeta potentials of bubbles and particles were similar under identical conditions, and their charges were influenced by metal ion concentration and pH. Maximum removal efficiency was 98 and 12% in the presence and absence of flocculation, respectively. Removal efficiency was higher when particle size was similar to bubble size. These results agree with modelling simulations and indicate that collision efficiency is greater when the zeta potential of one is negative and that of the other is positive and when their sizes are similar.

  1. Advanced CO2 removal process control and monitor instrumentation development

    NASA Technical Reports Server (NTRS)

    Heppner, D. B.; Dalhausen, M. J.; Klimes, R.

    1982-01-01

    A progam to evaluate, design and demonstrate major advances in control and monitor instrumentation was undertaken. A carbon dioxide removal process, one whose maturity level makes it a prime candidate for early flight demonstration was investigated. The instrumentation design incorporates features which are compatible with anticipated flight requirements. Current electronics technology and projected advances are included. In addition, the program established commonality of components for all advanced life support subsystems. It was concluded from the studies and design activities conducted under this program that the next generation of instrumentation will be greatly smaller than the prior one. Not only physical size but weight, power and heat rejection requirements were reduced in the range of 80 to 85% from the former level of research and development instrumentation. Using a microprocessor based computer, a standard computer bus structure and nonvolatile memory, improved fabrication techniques and aerospace packaging this instrumentation will greatly enhance overall reliability and total system availability.

  2. Removable inner turbine shell with bucket tip clearance control

    DOEpatents

    Sexton, Brendan F.; Knuijt, Hans M.; Eldrid, Sacheverel Q.; Myers, Albert; Coneybeer, Kyle E.; Johnson, David Martin; Kellock, Iain R.

    2000-01-01

    A turbine includes a plurality of inner shell sections mounting first and second stage nozzle and shroud portions. The inner shell sections are pinned to an outer containment shell formed of sections to preclude circumferential movement of the inner shell relative to the outer shell and enable thermal expansion and contraction of the inner shell relative to the outer shell. Positive bucket tip clearance control is afforded by passing a thermal medium about the inner shell in heat transfer relation with the shrouds about the first and second stage bucket tips, the thermal medium being provided from a source of heating/cooling fluid independent of the turbine. Access is provided to the rotor and turbine buckets by removing the outer and inner shell sections.

  3. Dislodgement and removal of dust-particles from a surface by a technique combining acoustic standing wave and airflow.

    PubMed

    Chen, Di; Wu, Junru

    2010-01-01

    It is known that there are many fine particles on the moon and Mars. Their existence may cause risk for the success of a long-term project for NASA, i.e., exploration and habitation of the moon and Mars. These dust-particles might cover the solar panels, making them fail to generate electricity, and they might also penetrate through seals on space suits, hatches, and vehicle wheels causing many incidents. The fine particles would be hazardous to human health if they were inhaled. Development of robust dust mitigation technology is urgently needed for the viable long-term exploration and habilitation of either the moon or Mars. A feasibility study to develop a dust removal technique, which may be used in space-stations or other enclosures for habitation, is reported. It is shown experimentally that the acoustic radiation force produced by a 13.8 kHz 128 dB sound-level standing wave between a 3 cm-aperture tweeter and a reflector separated by 9 cm is strong enough to overcome the van der Waals adhesive force between the dust-particles and the reflector-surface. Thus the majority of fine particles (>2 microm diameter) on a reflector-surface can be dislodged and removed by a technique combining acoustic levitation and airflow methods. The removal efficiency deteriorates for particles of less than 2 microm in size.

  4. Microfluidic Controlled Conformal Coating of Particles

    NASA Astrophysics Data System (ADS)

    Tsai, Scott; Wexler, Jason; Wan, Jiandi; Stone, Howard

    2011-11-01

    Coating flows are an important class of fluid mechanics problems. Typically a substrate is coated with a moving continuous film, but it is also possible to consider coating of discrete objects. In particular, in applications involving coating of particles that are useful in drug delivery, the coatings act as drug-carrying vehicles, while in cell therapy a thin polymeric coating is required to protect the cells from the host's immune system. Although many functional capabilities have been developed for lab-on-a-chip devices, a technique for coating has not been demonstrated. We present a microfluidic platform developed to coat micron-size spheres with a thin aqueous layer by magnetically pulling the particles from the aqueous phase to the non-aqueous phase in a co-flow. Coating thickness can be adjusted by the average fluid speed and the number of beads encapsulated inside a single coat is tuned by the ratio of magnetic to interfacial forces acting on the beads.

  5. Quantification of online removal of refractory black carbon using laser-induced incandescence in the single particle soot photometer

    DOE PAGES

    Aiken, Allison C.; McMeeking, Gavin R.; Levin, Ezra J. T.; ...

    2016-04-05

    Refractory black carbon (rBC) is an aerosol that has important impacts on climate and human health. rBC is often mixed with other species, making it difficult to isolate and quantify its important effects on physical and optical properties of ambient aerosol. To solve this measurement challenge, a new method to remove rBC was developed using laser-induced incandescence (LII) by Levin et al. in 2014. Application of the method with the Single Particle Soot Photometer (SP2) is used to determine the effects of rBC on ice nucleating particles (INP). Here, we quantify the efficacy of the method in the laboratory usingmore » the rBC surrogate Aquadag. Polydisperse and mobility-selected samples (100–500 nm diameter, 0.44–36.05 fg), are quantified by a second SP2. Removal rates are reported by mass and number. For the mobility-selected samples, the average percentages removed by mass and number of the original size are 88.9 ± 18.6% and 87.3 ± 21.9%, respectively. Removal of Aquadag is efficient for particles >100 nm mass-equivalent diameter (dme), enabling application for microphysical studies. However, the removal of particles ≤100 nm dme is less efficient. Absorption and scattering measurements are reported to assess its use to isolate brown carbon (BrC) absorption. Scattering removal rates for the mobility-selected samples are >90% on average, yet absorption rates are 53% on average across all wavelengths. Therefore, application to isolate effects of microphysical properties determined by larger sizes is promising, but will be challenging for optical properties. Lastly, the results reported also have implications for other instruments employing internal LII, e.g., the Soot Particle Aerosol Mass Spectrometer (SP-AMS).« less

  6. Quantification of online removal of refractory black carbon using laser-induced incandescence in the single particle soot photometer

    SciTech Connect

    Aiken, Allison C.; McMeeking, Gavin R.; Levin, Ezra J. T.; Dubey, Manvendra K.; DeMott, Paul J.; Kreidenweis, Sonia M.

    2016-04-05

    Refractory black carbon (rBC) is an aerosol that has important impacts on climate and human health. rBC is often mixed with other species, making it difficult to isolate and quantify its important effects on physical and optical properties of ambient aerosol. To solve this measurement challenge, a new method to remove rBC was developed using laser-induced incandescence (LII) by Levin et al. in 2014. Application of the method with the Single Particle Soot Photometer (SP2) is used to determine the effects of rBC on ice nucleating particles (INP). Here, we quantify the efficacy of the method in the laboratory using the rBC surrogate Aquadag. Polydisperse and mobility-selected samples (100–500 nm diameter, 0.44–36.05 fg), are quantified by a second SP2. Removal rates are reported by mass and number. For the mobility-selected samples, the average percentages removed by mass and number of the original size are 88.9 ± 18.6% and 87.3 ± 21.9%, respectively. Removal of Aquadag is efficient for particles >100 nm mass-equivalent diameter (dme), enabling application for microphysical studies. However, the removal of particles ≤100 nm dme is less efficient. Absorption and scattering measurements are reported to assess its use to isolate brown carbon (BrC) absorption. Scattering removal rates for the mobility-selected samples are >90% on average, yet absorption rates are 53% on average across all wavelengths. Therefore, application to isolate effects of microphysical properties determined by larger sizes is promising, but will be challenging for optical properties. Lastly, the results reported also have implications for other instruments employing internal LII, e.g., the Soot Particle Aerosol Mass Spectrometer (SP-AMS).

  7. Pyrene removal from contaminated soils by modified Fenton oxidation using iron nano particles

    PubMed Central

    2013-01-01

    Background The problems related to conventional Fenton oxidation, including low pH required and production of considerable amounts of sludge have led researchers to investigate chelating agents which might improve the operating range of pH and the use of nano iron particle to reduce the excess sludge. The pyrene removal from contaminated soils by modified Fenton oxidation at neutral pH was defined as the main objective of the current study. Methods Varying concentrations of H2O2 (0-500 mM) and iron nano oxide (0-60 mM), reaction times of 0.5-24 hours and variety of chelating agents including sodium pyrophosphate, sodium citrate, ethylene diamine tetraacetic, fulvic and humic acid were all investigated at pyrene concentration levels of 100 – 500 mg/kg. Results By applying the following conditions (H2O2 concentration of 300 mM, iron nano oxide of 30 mM, sodium pyrophosphate as chelating agent, pH 3 and reaction time of 6 hours) the pyrene removal efficiency at an initial concentration of 100 mg/kg was found to be 99%. As a result, the pyrene concentration was reduced from 100 to 93 mg/kg once the above optimum conditions are met. Conclusions In this research, the modified Fenton oxidation using iron nano oxide at optimum conditions is introduced as an efficient alternative method in lab scale for chemical remediation or pre-treatment of soils contaminated by pyrene at neutral pH. PMID:24499620

  8. Sonochemical synthesis of silica particles and their size control

    NASA Astrophysics Data System (ADS)

    Kim, Hwa-Min; Lee, Chang-Hyun; Kim, Bonghwan

    2016-09-01

    Using an ultrasound-assisted sol-gel method, we successfully synthesized very uniformly shaped, monodisperse, and size-controlled spherical silica particles from a mixture of ethanol, water, and tetraethyl orthosilicate in the presence of ammonia as catalyst, at room temperature. The diameters of the silica particles were distributed in the range from 40 to 400 nm; their morphology was well characterized by scanning electron microscopy. The silica particle size could be adjusted by choosing suitable concentrations of ammonium hydroxide and water, which in turn determined the nucleation and growth rates of the particles during the reaction. This sonochemical-based silica synthesis offers an alternative way to produce spherical silica particles in a relatively short reaction time. Thus, we suggest that this simple, low-cost, and efficient method of preparing uniform silica particles of various sizes will have practical and wide-ranging industrial applicability.

  9. Neural Networks for Modeling and Control of Particle Accelerators

    DOE PAGES

    Edelen, A. L.; Biedron, S. G.; Chase, B. E.; ...

    2016-04-01

    Myriad nonlinear and complex physical phenomena are host to particle accelerators. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems,more » as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Moreover, many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. For the purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). We also describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.« less

  10. Neural Networks for Modeling and Control of Particle Accelerators

    SciTech Connect

    Edelen, A. L.; Biedron, S. G.; Chase, B. E.; Edstrom, D.; Milton, S. V.; Stabile, P.

    2016-04-01

    Myriad nonlinear and complex physical phenomena are host to particle accelerators. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems, as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Moreover, many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. For the purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). We also describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.

  11. Zero-valent iron particles embedded on the mesoporous silica-carbon for chromium (VI) removal from aqueous solution

    NASA Astrophysics Data System (ADS)

    Xiong, Kun; Gao, Yuan; Zhou, Lin; Zhang, Xianming

    2016-09-01

    Nanoscale zero-valent iron (nZVI) particles were embedded on the walls of mesoporous silica-carbon (MSC) under the conditions of high-temperature carbonization and reduction and used to remove chromium (VI) from aqueous solution. The structure and textural properties of nZVI-MSC were characterized by the powder X-ray diffraction, transmission electron microscopy and N2 adsorption and desorption. The results show that nZVI-MSC has highly ordered mesoporous structure and large surface area, indistinguishable with that of MSC. Compared with the support MSC and iron particles supported on the activated carbon (nZVI/AC), nZVI-MSC exhibited much higher Cr(VI) removal efficiency with about 98 %. The removal process obeys a pseudo first-order model. Such excellent performance of nZVI-MSC could be ascribed to the large surface and iron particles embedded on the walls of the MSC, forming an intimate contact with the MSC. It is proposed that this feature might create certain micro-electrode on the interface of iron particles and MSC, which prevented the formation of metal oxide on the surface and provided fresh Fe surface for Cr(VI) removal.

  12. Mechanism of natural organic matter removal by polyaluminum chloride: effect of coagulant particle size and hydrolysis kinetics.

    PubMed

    Yan, Mingquan; Wang, Dongsheng; Ni, Jinren; Qu, Jiuhui; Chow, Christopher W K; Liu, Hailong

    2008-07-01

    The mechanism of natural organic matter (NOM) removal by AlCl(3) and polyaluminum chloride (PACl) was investigated through bench-scale tests. The fraction distributions of NOM and residual Al after coagulation in solution, colloid and sediment were analyzed as changes of coagulant dosage and pH. The influence of NOM, coagulant dose and pH on coagulation kinetics of AlCl(3) was investigated using photometric dispersion analyzer compared with PACl. Monomeric Al species (Al(a)) shows high ability to satisfy some unsaturated coordinate bonds of NOM to facilitate particle and NOM removal, while most of the flocs formed by Al(a) are small and difficult to settle. Medium polymerized Al species (Al(b)) can destabilize particle and NOM efficiently, while some flocs formed by Al(b) are not large and not easy to precipitate as compared to those formed by colloidal or solid Al species (Al(c)). Thus, Al(c) could adsorb and remove NOM efficiently. The removal of contaminant by species of Al(a), Al(b) and Al(c) follows mechanisms of complexation, neutralization and adsorption, respectively. Unlike preformed Al(b) in PACl, in-situ-formed Al(b) can remove NOM and particle more efficiently via the mechanism of further hydrolysis and transfer into Al(c) during coagulation. While the presence of NOM would reduce Al(b) formed in-situ due to the complexation of NOM and Al(a).

  13. Enhanced Removal of Hydrophobic Gas by Aerial Ultrasonic Waves and Two Kinds of Water Mists of Different Particle Sizes

    NASA Astrophysics Data System (ADS)

    Matsumoto, Keisuke; Miura, Hikaru

    2012-07-01

    Air pollutants can cause health problems, such as bronchitis and cancer, and are now recognized as a social problem. Hence, a method is proposed for the collection and removal of gaseous air pollutants by aerial ultrasonic waves and water mist. Typically, gas removal effects are studied using lemon oil vapor (“lemon gas”), which is a hydrophobic gas. Previous experiments using lemon gas have shown that a removal rate of up to 40% can be achieved in an intense standing wave at 20 kHz, for an amount of water mist of 1.39 cm3/s and an electrical input power of 50 W. Increasing the surface area of the water mist leads to greater removal of hydrophobic gas. In this study, the effects of gas removal are examined by conducting experiments using intense aerial ultrasonic waves to disperse two kinds of water mists, each composed of particles of different sizes: small particles (diameter: ≈3 µm) and conventional large particles (diameter: ≈60 µm).

  14. Method for removing tilt control in adaptive optics systems

    DOEpatents

    Salmon, Joseph Thaddeus

    1998-01-01

    A new adaptive optics system and method of operation, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G'=(I-X(X.sup.T X).sup.-1 X.sup.T)G(I-A)

  15. Method for removing tilt control in adaptive optics systems

    DOEpatents

    Salmon, J.T.

    1998-04-28

    A new adaptive optics system and method of operation are disclosed, whereby the method removes tilt control, and includes the steps of using a steering mirror to steer a wavefront in the desired direction, for aiming an impinging aberrated light beam in the direction of a deformable mirror. The deformable mirror has its surface deformed selectively by means of a plurality of actuators, and compensates, at least partially, for existing aberrations in the light beam. The light beam is split into an output beam and a sample beam, and the sample beam is sampled using a wavefront sensor. The sampled signals are converted into corresponding electrical signals for driving a controller, which, in turn, drives the deformable mirror in a feedback loop in response to the sampled signals, for compensating for aberrations in the wavefront. To this purpose, a displacement error (gradient) of the wavefront is measured, and adjusted by a modified gain matrix, which satisfies the following equation: G{prime} = (I{minus}X(X{sup T} X){sup {minus}1}X{sup T})G(I{minus}A). 3 figs.

  16. Schedules of controlled substances: removal of naloxegol from control. Final rule.

    PubMed

    2015-01-23

    With the issuance of this final rule, the Administrator of the Drug Enforcement Administration removes naloxegol ((5[alpha],6[alpha])-17-allyl-6-((20-hydroxy-3,6,9,12,15,18-hexaoxaicos-1-yl)oxy)-4,5-epoxymorphinon-3,14-diol) and its salts from the schedules of the Controlled Substances Act (CSA). This scheduling action is pursuant to the CSA which requires that such actions be made on the record after opportunity for a hearing through formal rulemaking. Prior to the effective date of this rule, naloxegol was a schedule II controlled substance because it can be derived from opium alkaloids. This action removes the regulatory controls and administrative, civil, and criminal sanctions applicable to controlled substances, including those specific to schedule II controlled substances, on persons who handle (manufacture, distribute, reverse distribute, dispense, conduct research, import, export, or conduct chemical analysis) or propose to handle naloxegol.

  17. Advanced coal-fueled industrial cogeneration gas turbine system particle removal system development

    SciTech Connect

    Stephenson, M.

    1994-03-01

    Solar Turbines developed a direct coal-fueled turbine system (DCFT) and tested each component in subscale facilities and the combustion system was tested at full-scale. The combustion system was comprised of a two-stage slagging combustor with an impact separator between the two combustors. Greater than 90 percent of the native ash in the coal was removed as liquid slag with this system. In the first combustor, coal water slurry mixture (CWM) was injected into a combustion chamber which was operated loan to suppress NO{sub x} formation. The slurry was introduced through four fuel injectors that created a toroidal vortex because of the combustor geometry and angle of orientation of the injectors. The liquid slag that was formed was directed downward toward an impaction plate made of a refractory material. Sixty to seventy percent of the coal-borne ash was collected in this fashion. An impact separator was used to remove additional slag that had escaped the primary combustor. The combined particulate collection efficiency from both combustors was above 95 percent. Unfortunately, a great deal of the original sulfur from the coal still remained in the gas stream and needed to be separated. To accomplish this, dolomite or hydrated lime were injected in the secondary combustor to react with the sulfur dioxide and form calcium sulfite and sulfates. This solution for the sulfur problem increased the dust concentrations to as much as 6000 ppmw. A downstream particulate control system was required, and one that could operate at 150 psia, 1850-1900{degrees}F and with low pressure drop. Solar designed and tested a particulate rejection system to remove essentially all particulate from the high temperature, high pressure gas stream. A thorough research and development program was aimed at identifying candidate technologies and testing them with Solar`s coal-fired system. This topical report summarizes these activities over a period beginning in 1987 and ending in 1992.

  18. Controlling Particle Morphologies at Fluid Interfaces: Macro- and Micro- approaches

    NASA Astrophysics Data System (ADS)

    Beesabathuni, Shilpa Naidu

    The controlled generation of varying shaped particles is important for many applications: consumer goods, biomedical diagnostics, food processing, adsorbents and pharmaceuticals which can benefit from the availability of geometrically complex and chemically inhomogeneous particles. This thesis presents two approaches to spherical and non-spherical particle synthesis using macro and microfluidics. In the first approach, a droplet microfluidic technique is explored to fabricate spherical conducting polymer, polyaniline, particles with precise control over morphology and functionality. Microfluidics has recently emerged as an important alternate to the synthesis of complex particles. The conducting polymer, polyaniline, is widely used and known for its stability, high conductivity, and favorable redox properties. In this approach, monodisperse micron-sized polyaniline spherical particles were synthesized using two-phase droplet microfluidics from Aniline and Ammonium persulfate oxidative polymerization in an oil-based continuous phase. The morphology of the polymerized particles is porous in nature which can be used for encapsulation as well as controlled release applications. Encapsulation of an enzyme, glucose oxidase, was also performed using the technique to synthesize microspheres for glucose sensing. The polymer microspheres were characterized using SEM, UV-Vis and EDX to understand the relationship between their microstructure and stability. In the second approach, molten drop impact in a cooling aqueous medium to generate non-spherical particles was explored. Viscoelastic wax based materials are widely used in many applications and their performance and application depends on the particle morphology and size. The deformation of millimeter size molten wax drops as they impacted an immiscible liquid interface was investigated. Spherical molten wax drops impinged on a cooling water bath, then deformed and as a result of solidification were arrested into various

  19. Controlled epitaxial graphene growth within removable amorphous carbon corrals

    SciTech Connect

    Palmer, James; Hu, Yike; Hankinson, John; Guo, Zelei; Heer, Walt A. de; Kunc, Jan; Berger, Claire

    2014-07-14

    We address the question of control of the silicon carbide (SiC) steps and terraces under epitaxial graphene on SiC and demonstrate amorphous carbon (aC) corrals as an ideal method to pin SiC surface steps. aC is compatible with graphene growth, structurally stable at high temperatures, and can be removed after graphene growth. For this, aC is first evaporated and patterned on SiC, then annealed in the graphene growth furnace. There at temperatures above 1200 °C, mobile SiC steps accumulate at the aC corral that provide effective step flow barriers. Aligned step free regions are thereby formed for subsequent graphene growth at temperatures above 1330 °C. Atomic force microscopy imaging supports the formation of step-free terraces on SiC with the step morphology aligned to the aC corrals. Raman spectroscopy indicates the presence of good graphene sheets on the step-free terraces.

  20. Morphological Control and Characterization of Monodispersed Ceria Particles

    SciTech Connect

    Minamidate, Y.; Yin, S.; Devaraju, M. K.; Sato, T.

    2010-11-24

    The morphological control of cerium oxide particles was carried out by a homogeneous precipitation followed by calcination in air at 400 deg. C. The effects of pre-aging temperature, aging time and precipitation reagents on the morphologies of final products were investigated. When urea was used as a precipitation reagent, monodispersed spherical and flake-like cerium carbonate hydroxide precursor was precipitated in the solution at 90 deg. C for 2 h after pre-aging at 25 deg. C - 50 deg. C for 24-72 h. On the other hand, monodispersed nanosize rod-like cerium hydroxide particles were obtained using triethanolamine as precipitation reagent. Ceria particles with the same morphologies and slightly smaller particle size than those of as-prepared cerium precursor could be obtained after calcination in air at 400 deg. C. Physical-chemical characteristics of the monodispersed cerium oxide particles were evaluated.

  1. Rock sampling. [method for controlling particle size distribution

    NASA Technical Reports Server (NTRS)

    Blum, P. (Inventor)

    1971-01-01

    A method for sampling rock and other brittle materials and for controlling resultant particle sizes is described. The method involves cutting grooves in the rock surface to provide a grouping of parallel ridges and subsequently machining the ridges to provide a powder specimen. The machining step may comprise milling, drilling, lathe cutting or the like; but a planing step is advantageous. Control of the particle size distribution is effected primarily by changing the height and width of these ridges. This control exceeds that obtainable by conventional grinding.

  2. Variation of Particle Control with Changes in Divertor Geometry

    SciTech Connect

    Petrie, T W; Allen, S L; Brooks, N H; Fenstermacher, M E; Ferron, J R; Greenfield, C M; Groth, M; Hyatt, A W; Leonard, A W; Luce, T C; Mahdavi, M A; Murakami, M; Porter, G D; Rensink, M E; Schaffer, M J; Wade, M R; Watkins, J G; West, W P; Wolf, N S

    2004-10-18

    Recent experiments on DIII-D point to the importance of two factors in determining how effectively the deuterium particle inventory in a tokamak plasma can be controlled through pumping at the divertor target(s): (1) the divertor magnetic balance, i.e., the degree to which the divertor topology is single-null (SN) or double-null (DN), and (2) the direction of the of Bx{divergent}B ion drift with respect to the X-point(s). Changes in divertor magnetic balance near the DN shape have a much stronger effect on the particle exhaust rate at the inner divertor target(s) than on the particle exhaust rate at the outer divertor target(s). The particle exhaust rate for the DN shape is strongest at the outer strike point opposite the Bx{divergent}B ion particle drift direction. Our data suggests that the presence of Bx{divergent}B and ExB ion particle drifts in the scrapeoff layer (SOL) and divertors play an important role in the particle exhaust rates of DN and near-DN plasmas. Particle exhaust rates are shown to depend strongly on the edge (pedestal) density n{sub e,PED}. In the lower range of densities considered in this study, i.e., n{sub e,PED}/ n{sub GREENWALD}<0.4, particle exhaust rates are also found to be approximately proportional to the deuterium recycling intensity in front of the respective plenum entrance. Our results are shown to have implications for particle control in ITER and other future tokamaks.

  3. Enhanced reactivity of microscale Fe/Cu bimetallic particles (mFe/Cu) with persulfate (PS) for p-nitrophenol (PNP) removal in aqueous solution.

    PubMed

    Ji, Qingqing; Li, Jun; Xiong, Zhaokun; Lai, Bo

    2017-04-01

    In this study, batch experiments were conducted to examine the enhanced reactivity of microscale Fe/Cu bimetallic particles (mFe/Cu) with persulfate (PS) for p-nitrophenol (PNP) removal in aqueous solution. The key operating parameters (i.e., theoretical Cu mass loadings (TMLCu), mFe/Cu dosage, PS dose, initial pH and temperature) were optimized by the batch experiments, respectively. The experimental data were followed well the pseudo-first-order kinetic model. Result reveals that refractory PNP (500 mg L(-1)) was effectively degraded by mFe/Cu-PS system with removal of 98.4% and kobs of 1.91 min(-1) after only 3 min treatment under the optimal operating conditions. Moreover, compared with control experiments (i.e., mFe/Cu, microscale Fe(0) with PS (mFe(0)-PS), and PS alone), mFe/Cu-PS system exerted better performance for PNP removal due to the strong synergistic effect between PS and mFe/Cu. According to the analysis results of degradation kinetics of PNP, COD (chemical oxygen demand) removal, UV-vis absorption spectra and the intermediates formed, the results reveal that the PNP removal by mFe/Cu-PS system was mainly attributed to reduction accompanied slight oxidation. And based on the analysis of surface characteristics of mFe/Cu particles, it is further demonstrated that PS could enhance the reactivity of mFe/Cu through rapid corrosion of iron surface and decrease of surface passivation of mFe/Cu surface when the low molar ratio of PS to mFe/Cu (i.e., 1:43) was used in this study. These results also illustrates mFe/Cu-PS can be as a high efficient pretreatment technology for the removal of toxic refractory PNP from wastewater.

  4. Particle removal by vegetation: comparison in a forest and a wetland.

    PubMed

    Liu, Jiakai; Zhai, Jiexiu; Zhu, Lijuan; Yang, Yilian; Liu, Jiatong; Zhang, Zhenming

    2017-01-01

    Vegetation collection is one of the most effective scavenging methods but relevant studies are limited. It can be described by some abstract parameters such as collection rates and deposition fluxes within the canopy. In order to estimate the dry deposition within the canopy of particular matters (PMs) in Beijing, a highly particle-polluted city, and reveal the PM pollution-removal abilities of plants in wetlands and forests, concentration and meteorological data were collected during the daytime in an artificial forest and a wetland in the Olympic Park in Beijing. The dry depositions within the canopy and vegetation collection rates were calculated by a well-developed model and validated by measured deposition fluxes in 11 random experiment days. The experiment year was divided into three plant growth stages based on canopy density, and the day was divided into four different times. Two heights, 10 and 1.5 m, were defined in the forest while in the wetland, 0.5 and 1.5 m were defined. The results showed that in Beijing, the most severe pollution by PMs occurs in the non-leaf stage (NS), and the full-leaf stage (FS) is the cleanest stage. In NS, namely winter, more fossil fuel was used for worms in Beijing and peripheral areas and this might be the reason for the serious pollution condition. Within the canopy, PM deposition fluxes in the wetland are more than those in the forest, but the vegetation collection rates of the forest are higher. The lower temperature conditions led to more dry deposition, and the larger canopy contributed to the higher collection rates. During the daytime, over the year, the deposition of PM10 in three plant growth stages is NS ≥ half-leaf stages (HS) ≥ FS, whereas the deposition of PM2.5 is NS ≥ FS ≥ HS, and during the daytime, the maximum deposition fluxes occur in 6:00-9:00 in the wetland while the minimum deposition values occur in 15:00-18:00. This phenomenon was related to the temporal variation of particle

  5. Magnetophoretic circuits for digital control of single particles and cells

    NASA Astrophysics Data System (ADS)

    Lim, Byeonghwa; Reddy, Venu; Hu, Xinghao; Kim, Kunwoo; Jadhav, Mital; Abedini-Nassab, Roozbeh; Noh, Young-Woock; Lim, Yong Taik; Yellen, Benjamin B.; Kim, Cheolgi

    2014-05-01

    The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects.

  6. Control over Colloidal Particle Morphology by Dispersion Polymerization

    NASA Astrophysics Data System (ADS)

    Peng, B.

    2013-03-01

    The main subject of this thesis is the structure and morphology control of colloidal polymer particles, in particular, poly(methyl methacrylate) (PMMA) particles, by dispersion polymerization in polar solvents. The structure control, ranging from surface morphology and internal structure to shape manipulation of polymer particles, was attempted through copolymerization of monomers with various types of materials, such as cross-linkers, dyes, and colloidal silica spheres or rods. The obtained spherical or non-spherical particles are interesting as model systems as they mimic molecules at colloidal scales. Their phase behavior can be studied in the presence or absence of external fields (like electric and gravity fields). Additionally, they can be used for various applications, such as photonic crystals

  7. Magnetophoretic circuits for digital control of single particles and cells.

    PubMed

    Lim, Byeonghwa; Reddy, Venu; Hu, XingHao; Kim, KunWoo; Jadhav, Mital; Abedini-Nassab, Roozbeh; Noh, Young-Woock; Lim, Yong Taik; Yellen, Benjamin B; Kim, CheolGi

    2014-05-14

    The ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects.

  8. Control of respirable particles in indoor air with portable air cleaners

    NASA Astrophysics Data System (ADS)

    Offermann, F. J.; Sextro, R. G.; Fisk, W. J.; Grimsrud, D. T.; Nazaroff, W. W.; Nero, A. V.; Revzan, K. L.; Yater, J.

    Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles using in situ chamber decay tests. Following injection of cigarette smoke in a room-size chamber, decay rates for particle concentrations were obtained for total number concentration and for number concentration by particle size with and without air cleaner operation. The size distribution of the tobacco smoke particles was log normal with a count median diameter of 0.15 μm and a geometric standard deviation of 2.0. Without air cleaner operation, the natural mass-averaged surface deposition rate of particles was observed to be 0.1 h -1. Air cleaning rates for particles were found to be negligible for several small panel-filter devices, a residential-sized ion-generator, and a pair of mixing fans. Electrostatic precipitators and extended surface filters removed particles at substantial rates, and a HEPA-type filter was most efficient air cleaner studied.

  9. Control of Respirable Particles in Indoor Air with Portable AirCleaners

    SciTech Connect

    Offermann, F.J.; Sextro, R.G.; Fisk, W.J.; Grimsrud, D.T.; Nazaroff, W.W.; Nero, A.V.; Revzan, K.L.; Yater, J.

    1984-10-01

    Eleven portable air cleaning devices have been evaluated for control of indoor concentrations of respirable particles using in situ chamber decay tests. Following injection of cigarette smoke in a room-size chamber, decay rates for particle concentrations were obtained for total number concentration and for number concentration by particle size with and without air cleaner operation. The size distribution of the tobacco smoke particles was log normal with a count median diameter of 0.15 {micro}m and a geometric standard deviation of 2.0. Without air cleaner operation, the natural mass-averaged surface deposition rate of particles was observed to be 0.1 h{sup -1}. Air cleaning rates for particles were found to be negligible for several small panel-filter devices, a residential-sized ion-generator, and a pair of mixing fans. Electrostatic precipitators and extended surface filters removed particles at substantial rates, and a HEPA-type filter was the most efficient air cleaner studied.

  10. Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

    PubMed

    Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

    2008-11-01

    A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

  11. Method of removing entrained particles from flue gas and composition of matter

    SciTech Connect

    Radway, J.E.; Bennett, R.P.

    1988-04-19

    A composition of matter to treat particles entrained in flue gas, is described comprising: a caustic liquid used to adjust resistivity of the entrained particles; and inert particulate matter supporting the caustic liquid for inhibiting chemical action of the caustic liquid until used to adjust the resistivity of the entrained particles, the inert particulate matter supporting sufficient caustic liquid to adjust the resistivity of the entrained particles.

  12. Controlled particle transport in a plasma chamber with striped electrode

    SciTech Connect

    Jiang Ke; Li Yangfang; Shimizu, T.; Konopka, U.; Thomas, H. M.; Morfill, G. E.

    2009-12-15

    The controlled transport of micrometer size dust particles in a parallel-plate radio frequency discharge has been investigated. The lower stainless steel electrode consisted of 100 independently controllable electrical metal stripes. The voltage signals on these stripes were modulated, causing traveling plasma sheath distortions. Because the particles trapped in local potential wells moved according to the direction of the distortion, the transport velocity could be actively controlled by adjusting frequencies and phase shifts of the applied periodic voltage signals. To investigate the detailed principle of this transport, molecular dynamic simulations was performed to reproduce the observations with the plasma background conditions calculated by separated particle-in-cell simulations for the experimental parameters. The findings will help develop novel technologies for investigating large-scale complex plasma systems and techniques for achieving clean environments in plasma processing reactors.

  13. Optimizing osmotic pressure removes EBV particles from B95-8 host cells while maintaining normal activity.

    PubMed

    Pan, Min; Shen, Jing; Cai, Jie

    2013-03-01

    This study demonstrates the removal of virus particles from B95-8 host cells that maintain normal activity under optimal osmotic pressure. After infecting B95-8 cells with Epstein-Barr virus (EBV) particles, the cells were treated with isosmotic solution [0.90% NaCl (330 mOsm/kg H(2)O)], hyposmotic solutions [0.36% NaCl (115 mOsm/kg H(2)O) and 0.27% NaCl (93 mOsm/kg H(2)O)] and distilled water. The pumping levels of virus particles were observed by inverse phase contrast microscopy and transmission electron microscopy (TEM). After treatment with the hyposmotic solutions, the following results were observed: firstly, after culturing for 24 and 48 h, the B95-8 cells in the hyposmotic solutions grew as well as the cells cultured in the isosmotic solution. Secondly, the virus particles in the B95-8 host cells overflowed onto the surface of the cells, while the organelle structures remained intact. This phenomenon was repeated in the removal of human immunodeficiency virus (HIV) from leukomonocytes. By optimizing the osmotic pressure, the activity of the B95-8 host cells was retained and the EBV particles were transported from the cells onto the cell surface.

  14. A comparison of biologically active filters for the removal of ozone by-products, turbidity, and particles

    SciTech Connect

    Coffey, B.M.; Krasner, S.W.; Sclimenti, M.J.; Hacker, P.A.; Gramith, J.T.

    1996-11-01

    Biofiltration tests were performed at the Metropolitan Water District of Southern California`s 5.5-mgd (21,000 m{sup 3}d) demonstration plant using two 400 ft{sup 2} (37 m{sup 2}) anthracite/sand filters and a 6 ft{sup 2} (0.56 m{sup 2}) granular activated carbon (GAC)/sand filter operated in parallel. The empty-bed contact time (EBCT) within the GAC and anthracite ranged from 2.1-3.1 min. The filters were evaluated based on (1) conventional filtration performance (turbidity, particle removal, and headloss); (2) removal of biodegradable ozone by-products (assimilable organic carbon [AOC], aldehydes, and aldoketoacids) after startup; (3) removal of biodegradable ozone by-products at steady state; and (4) resistance to short-term process upsets such as intermittent chlorination or filter out-of-service time. Approximately 80 percent formaldehyde removal was achieved by the anthracite/sand filter operated at a 2.1-min EBCT (6 gpm/ft{sup 2} [15 m/h]) within 8 days of ozone operation. The GAC/sand filter operated at the same rate achieved 80 percent removal within 1 day, possibly as an additive effect of adsorption and biological removal. In-depth aldehyde monitoring at four depths (0.5-min EBCT intervals) provided additional insight into the removal kinetics. During periods of warmer water temperature, from 20 to 48 percent of the AOC was removed in the flocculation/sedimentation basins by 40-75 percent. This percentage removal typically resulted in AOC concentrations within 40 {mu}g C/L of the raw, unozonated water levels.

  15. Magnetic control of particle injection in plasma based accelerators.

    PubMed

    Vieira, J; Martins, S F; Pathak, V B; Fonseca, R A; Mori, W B; Silva, L O

    2011-06-03

    The use of an external transverse magnetic field to trigger and to control electron self-injection in laser- and particle-beam driven wakefield accelerators is examined analytically and through full-scale particle-in-cell simulations. A magnetic field can relax the injection threshold and can be used to control main output beam features such as charge, energy, and transverse dynamics in the ion channel associated with the plasma blowout. It is shown that this mechanism could be studied using state-of-the-art magnetic fields in next generation plasma accelerator experiments.

  16. An Optically Controlled Microscale Elevator Using Plasmonic Janus Particles

    PubMed Central

    2015-01-01

    In this article, we report how Janus particles, composed of a silica sphere with a gold half-shell, can be not only stably trapped by optical tweezers but also displaced controllably along the axis of the laser beam through a complex interplay between optical and thermal forces. Scattering forces orient the asymmetric particle, while strong absorption on the metal side induces a thermal gradient, resulting in particle motion. An increase in the laser power leads to an upward motion of the particle, while a decrease leads to a downward motion. We study this reversible axial displacement, including a hysteretic jump in the particle position that is a result of the complex pattern of a tightly focused laser beam structure above the focal plane. As a first application we simultaneously trap a spherical gold nanoparticle and show that we can control the distance between the two particles inside the trap. This photonic micron-scale “elevator” is a promising tool for thermal force studies, remote sensing, and optical and thermal micromanipulation experiments. PMID:25950013

  17. An Optically Controlled Microscale Elevator Using Plasmonic Janus Particles.

    PubMed

    Nedev, Spas; Carretero-Palacios, Sol; Kühler, Paul; Lohmüller, Theobald; Urban, Alexander S; Anderson, Lindsey J E; Feldmann, Jochen

    2015-04-15

    In this article, we report how Janus particles, composed of a silica sphere with a gold half-shell, can be not only stably trapped by optical tweezers but also displaced controllably along the axis of the laser beam through a complex interplay between optical and thermal forces. Scattering forces orient the asymmetric particle, while strong absorption on the metal side induces a thermal gradient, resulting in particle motion. An increase in the laser power leads to an upward motion of the particle, while a decrease leads to a downward motion. We study this reversible axial displacement, including a hysteretic jump in the particle position that is a result of the complex pattern of a tightly focused laser beam structure above the focal plane. As a first application we simultaneously trap a spherical gold nanoparticle and show that we can control the distance between the two particles inside the trap. This photonic micron-scale "elevator" is a promising tool for thermal force studies, remote sensing, and optical and thermal micromanipulation experiments.

  18. Optofluidics incorporating actively controlled micro- and nano-particles

    PubMed Central

    Kayani, Aminuddin A.; Khoshmanesh, Khashayar; Ward, Stephanie A.; Mitchell, Arnan; Kalantar-zadeh, Kourosh

    2012-01-01

    The advent of optofluidic systems incorporating suspended particles has resulted in the emergence of novel applications. Such systems operate based on the fact that suspended particles can be manipulated using well-appointed active forces, and their motions, locations and local concentrations can be controlled. These forces can be exerted on both individual and clusters of particles. Having the capability to manipulate suspended particles gives users the ability for tuning the physical and, to some extent, the chemical properties of the suspension media, which addresses the needs of various advanced optofluidic systems. Additionally, the incorporation of particles results in the realization of novel optofluidic solutions used for creating optical components and sensing platforms. In this review, we present different types of active forces that are used for particle manipulations and the resulting optofluidic systems incorporating them. These systems include optical components, optofluidic detection and analysis platforms, plasmonics and Raman systems, thermal and energy related systems, and platforms specifically incorporating biological particles. We conclude the review with a discussion of future perspectives, which are expected to further advance this rapidly growing field. PMID:23864925

  19. Memoryless control of boundary concentrations of diffusing particles.

    PubMed

    Singer, A; Schuss, Z; Nadler, B; Eisenberg, R S

    2004-12-01

    Flux between regions of different concentration occurs in nearly every device involving diffusion, whether an electrochemical cell, a bipolar transistor, or a protein channel in a biological membrane. Diffusion theory has calculated that flux since the time of Fick (1855), and the flux has been known to arise from the stochastic behavior of Brownian trajectories since the time of Einstein (1905), yet the mathematical description of the behavior of trajectories corresponding to different types of boundaries is not complete. We consider the trajectories of noninteracting particles diffusing in a finite region connecting two baths of fixed concentrations. Inside the region, the trajectories of diffusing particles are governed by the Langevin equation. To maintain average concentrations at the boundaries of the region at their values in the baths, a control mechanism is needed to set the boundary dynamics of the trajectories. Different control mechanisms are used in Langevin and Brownian simulations of such systems. We analyze models of controllers and derive equations for the time evolution and spatial distribution of particles inside the domain. Our analysis shows a distinct difference between the time evolution and the steady state concentrations. While the time evolution of the density is governed by an integral operator, the spatial distribution is governed by the familiar Fokker-Planck operator. The boundary conditions for the time dependent density depend on the model of the controller; however, this dependence disappears in the steady state, if the controller is of a renewal type. Renewal-type controllers, however, produce spurious boundary layers that can be catastrophic in simulations of charged particles, because even a tiny net charge can have global effects. The design of a nonrenewal controller that maintains concentrations of noninteracting particles without creating spurious boundary layers at the interface requires the solution of the time

  20. Atomic Bose-Hubbard Systems with Single-Particle Control

    NASA Astrophysics Data System (ADS)

    Preiss, Philipp Moritz

    Experiments with ultracold atoms in optical lattices provide outstanding opportunities to realize exotic quantum states due to a high degree of tunability and control. In this thesis, I present experiments that extend this control from global parameters to the level of individual particles. Using a quantum gas microscope for 87Rb, we have developed a single-site addressing scheme based on digital amplitude holograms. The system self-corrects for aberrations in the imaging setup and creates arbitrary beam profiles. We are thus able to shape optical potentials on the scale of single lattice sites and control the dynamics of individual atoms. We study the role of quantum statistics and interactions in the Bose-Hubbard model on the fundamental level of two particles. Bosonic quantum statistics are apparent in the Hong-Ou-Mandel interference of massive particles, which we observe in tailored double-well potentials. These underlying statistics, in combination with tunable repulsive interactions, dominate the dynamics in single- and two-particle quantum walks. We observe highly coherent position-space Bloch oscillations, bosonic bunching in Hanbury Brown-Twiss interference and the fermionization of strongly interacting bosons. Many-body states of indistinguishable quantum particles are characterized by large-scale spatial entanglement, which is difficult to detect in itinerant systems. Here, we extend the concept of Hong-Ou-Mandel interference from individual particles to many-body states to directly quantify entanglement entropy. We perform collective measurements on two copies of a quantum state and detect entanglement entropy through many-body interference. We measure the second order Renyi entropy in small Bose-Hubbard systems and detect the buildup of spatial entanglement across the superfluid-insulator transition. Our experiments open new opportunities for the single-particle-resolved preparation and characterization of many-body quantum states.

  1. Method for non-contact particle manipulation and control of particle spacing along an axis

    DOEpatents

    Goddard, Gregory Russ; Kaduchak, Gregory; Jett, James Hubert; Graves, Steven Wayde

    2013-09-10

    One or more of the embodiments of the present invention provide for a method of non-contact particle manipulation and control of particle spacing along an axis which includes axial and radial acoustic standing wave fields. Particles are suspended in an aqueous solution, and this solution then flows into the cylindrical flow channel. While the solution flows through the flow channel, the outer structure of the flow channel is vibrated at a resonant frequency, causing a radial acoustic standing wave field to form inside the flow channel in the solution. These radial acoustic standing waves focus the particles suspended in the solution to the center axis of the cylindrical flow channel. At the same time, a transducer is used to create an axial acoustic standing wave field in the flow channel parallel to the axis of the flow channel. This drives the particles, which are already being focused to the center axis of the flow channel, to nodes or anti-nodes of the axial standing wave at half-wavelength intervals, depending on whether the particles are more or less dense and more or less compressible than the surrounding fluid.

  2. Damage Free Particle Removal from Extreme Ultraviolet Lithography Mask Layers by High Energy Laser Shock Wave Cleaning

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Gon; Yoo, Young-Sam; Kim, Tae-Geun; Ahn, Jinho; Lee, Jong-Myoung; Choi, Jae-Sung; Busnaina, Ahmed A.; Park, Jin-Goo

    2008-06-01

    Plasma shock waves induced by focusing a Q-switched Nd:YAG laser at a maximum energy of 1.8 J in air were characterized by a laser beam deflection method and were applied to 50 nm silica particle removal from a Al2O3/TaN/Ru/MoSi 40 pairs as the extreme ultraviolet lithography (EUVL) mask layers on silicon wafer. A high energy laser induced shock wave effectively removed 50 nm silica particles from the EUVL mask layers. The change of sample topography before and after laser shock cleaning was measured by an atomic force microscope. Surface damage was observed at a gap distance of 1.5 mm. The dimensions of the plasma plume were characterized as a function of the laser energy and focus-to-surface gap distance. The plasma plume was the main source for damaging the surface. A high energy laser induced shock wave with a gap distance of over 3 mm achieved damage-free sub-100 nm particle removal.

  3. Modeling and simulations of the removal of formaldehyde using silver nano-particles attached to granular activated carbon.

    PubMed

    Shin, SeungKyu; Song, JiHyeon

    2011-10-30

    A combined reaction, consisting of granular activated carbon (GAC) adsorption and catalytic oxidation, has been proposed to improve the removal efficiencies of formaldehyde, one of the major indoor air pollutants. In this study, silver nano-particles attached onto the surface of GAC (Ag-GAC) using the sputtering method were evaluated for the simultaneous catalytic oxidation and adsorption of formaldehyde. The evolution of CO(2) from the silver nano-particles indicated that formaldehyde was catalytically oxidized to its final product, with the oxidation kinetics expressed as pseudo-first order. In addition, a packed column test showed that the mass of formaldehyde removed by the Ag-GAC was 2.4 times higher than that by the virgin GAC at a gas retention time of 0.5s. However, a BET analysis showed that the available surface area and micro-pore volume of the Ag-GAC were substantially decreased due to the deposition of the silver nano-particles. To simulate the performance of the Ag-GAC, the homogeneous surface diffusion model (HSDM), developed for the prediction of the GAC column adsorption, was modified to incorporate the catalytic oxidation taking place on the Ag-GAC surface. The modified HSDM demonstrated that numerical simulations were consistent with the experimental data collected from the Ag-GAC column tests. The model predictions implied that the silver nano-particles deposited on the GAC reduced the adsorptive capacity due to decreasing the available surface for the diffusion of formaldehyde into the GAC, but the overall mass of formaldehyde removed by the Ag-GAC was increased due to catalytic oxidation as a function of the ratio of the surface coverage by the nano-particles.

  4. Compact and controlled microfluidic mixing and biological particle capture

    NASA Astrophysics Data System (ADS)

    Ballard, Matthew; Owen, Drew; Mills, Zachary Grant; Hesketh, Peter J.; Alexeev, Alexander

    2016-11-01

    We use three-dimensional simulations and experiments to develop a multifunctional microfluidic device that performs rapid and controllable microfluidic mixing and specific particle capture. Our device uses a compact microfluidic channel decorated with magnetic features. A rotating magnetic field precisely controls individual magnetic microbeads orbiting around the features, enabling effective continuous-flow mixing of fluid streams over a compact mixing region. We use computer simulations to elucidate the underlying physical mechanisms that lead to effective mixing and compare them with experimental mixing results. We study the effect of various system parameters on microfluidic mixing to design an efficient micromixer. We also experimentally and numerically demonstrate that orbiting microbeads can effectively capture particles transported by the fluid, which has major implications in pre-concentration and detection of biological particles including various cells and bacteria, with applications in areas such as point-of-care diagnostics, biohazard detection, and food safety. Support from NSF and USDA is gratefully acknowledged.

  5. Entropic control of particle sizes during viral self-assembly

    NASA Astrophysics Data System (ADS)

    Castelnovo, M.; Muriaux, D.; Faivre-Moskalenko, C.

    2013-03-01

    Morphologic diversity is observed across all families of viruses. However, these supra-molecular assemblies are produced most of the time in a spontaneous way through complex molecular self-assembly scenarios. The modeling of these phenomena remains a challenging problem within the emerging field of physical virology. We present in this work a theoretical analysis aiming at highlighting the particular role of configuration entropy in the control of viral particle size distribution. Specializing this model to retroviruses such as HIV-1, we predict a new mechanism of entropic control of both RNA uptake into the viral particle and of the particle's size distribution. Evidence of this peculiar behavior has recently been reported experimentally.

  6. Comparison of hydraulics and particle removal efficiencies in a mixed cell raceway and Burrows pond rearing system

    USGS Publications Warehouse

    Moffitt, Christine M.

    2016-01-01

    We compared the hydrodynamics of replicate experimental mixed cell and replicate standard Burrows pond rearing systems at the Dworshak National Fish Hatchery, ID, in an effort to identify methods for improved solids removal. We measured and compared the hydraulic residence time, particle removal efficiency, and measures of velocity using several tools. Computational fluid dynamics was used first to characterize hydraulics in the proposed retrofit that included removal of the traditional Burrows pond dividing wall and establishment of four counter rotating cells with appropriate drains and inlet water jets. Hydraulic residence time was subsequently established in the four full scale test tanks using measures of conductivity of a salt tracer introduced into the systems both with and without fish present. Vertical and horizontal velocities were also measured with acoustic Doppler velocimetry in transects across each of the rearing systems. Finally, we introduced ABS sinking beads that simulated fish solids then followed the kinetics of their removal via the drains to establish relative purge rates. The mixed cell raceway provided higher mean velocities and a more uniform velocity distribution than did the Burrows pond. Vectors revealed well-defined, counter-rotating cells in the mixed cell raceway, and were likely contributing factors in achieving a relatively high particle removal efficiency-88.6% versus 8.0% during the test period. We speculate retrofits of rearing ponds to mixed cell systems will improve both the rearing environments for the fish and solids removal, improving the efficiency and bio-security of fish culture. We recommend further testing in hatchery production trials to evaluate fish physiology and growth.

  7. Chemistry with spatial control using particles and streams†

    PubMed Central

    Kalinin, Yevgeniy V.; Murali, Adithya

    2012-01-01

    Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis. PMID:23145348

  8. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    SciTech Connect

    Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F.; Landsberger, S.

    1995-05-01

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration.

  9. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Ohio State Implementation Plan (SIP). (a) On February 21, 1997, the State of Ohio requested that the following rules and rule paragraphs be removed from the SIP because they have been amended or revoked by the State subsequent to their incorporation in the SIP: OAC 3745-21-02(C), OAC 3745-21-03(D), OAC...

  10. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Ohio State Implementation Plan (SIP). (a) On February 21, 1997, the State of Ohio requested that the following rules and rule paragraphs be removed from the SIP because they have been amended or revoked by the State subsequent to their incorporation in the SIP: OAC 3745-21-02(C), OAC 3745-21-03(D), OAC...

  11. 40 CFR 52.1890 - Removed control measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Ohio State Implementation Plan (SIP). (a) On February 21, 1997, the State of Ohio requested that the following rules and rule paragraphs be removed from the SIP because they have been amended or revoked by the State subsequent to their incorporation in the SIP: OAC 3745-21-02(C), OAC 3745-21-03(D), OAC...

  12. Simulation and control of sediment transport due to dam removal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents two case studies of post dam removal sedimentation in the United States. Two different one-dimensional channel evolution simulation models were used: CCHE1D and CONCEPTS, respectively. The first case is the application of CCHE1D to assess a long-term morphological response to the...

  13. Humidity control of particle emissions in aeolian systems

    NASA Astrophysics Data System (ADS)

    McKenna Neuman, Cheryl; Sanderson, Steven

    2008-06-01

    Humidity is an important control of the wind speed required to entrain particles into an air flow and is well known to vary on a global scale, as do dust emissions. This paper reports on wind tunnel experiments which quantify this control through placing a polymer capacitance sensor immediately at the bed surface. The sensor measured changes in the humidity (RH) of the pore air in real time. RH was varied between 15% and 80% and the critical wind speed determined for the release of particles to the air stream. The results strongly support earlier suggestions that fine particles are most affected in relatively dry atmospheres, particularly those which are tightly packed. An analytical model is proposed to describe this relationship which depends on determination of the matric potential from the Kelvin equation. The total contact area between particle asperities adjoined by pendular rings is represented as a power function of the number of layers of adsorbed water. The value of the exponent appears to be governed by the surface roughness of the particles and their packing arrangement. Parallel developments in colloid interface science and atomic force microscopy, relevant to industrial and pharmaceutical applications, support these conclusions in principle and will likely have an important bearing on future progress in parameterization of the proposed model.

  14. 15 CFR 768.10 - Removal of controls on less sophisticated items.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Removal of controls on less sophisticated items. 768.10 Section 768.10 Commerce and Foreign Trade Regulations Relating to Commerce and... REGULATIONS FOREIGN AVAILABILITY DETERMINATION PROCEDURES AND CRITERIA § 768.10 Removal of controls on...

  15. Application of electrochemical processes to membrane bioreactors for improving nutrient removal and fouling control.

    PubMed

    Borea, Laura; Naddeo, Vincenzo; Belgiorno, Vincenzo

    2017-01-01

    Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO4-P) and ammonia nitrogen (NH4-N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

  16. Abrasive Particle Trajectories and Material Removal Non-Uniformity during CMP and Filtration Characteristics of CMP Slurries - A Simulation and Experimental Study

    NASA Astrophysics Data System (ADS)

    Rastegar, Vahid

    Nanoscale finishing and planarization are integral process steps in multilevel metallization designs for integrated circuit (IC) manufacturing since it is necessary to ensure local and global surface planarization at each metal layer before depositing the next layer. Chemical mechanical planarization (CMP) has been widely recognized as the most promising technology to eliminate topographic variation and has allowed the construction of multilevel interconnection structures with a more regularly stacked sequence, resulting in better device performance [1]. Understanding fundamental of the CMP mechanisms can offer guidance to the control and optimization of the polishing processes. CMP kinematics based on slurry distribution and particle trajectories have a significant impact on MRR profiles. In this work a mathematical model to describe particle trajectories during chemical mechanical polishing was developed and extended to account for the effect of larger particles, particle location changes due to slurry dispensing and in-situ conditioning. Material removal rate (MRR) and within wafer non-uniformity (WIWNU) were determined based on the calculated particle trajectory densities. Rotary dynamics and reciprocating motion were optimized to obtain best MRR uniformity. Edge-fast MRR profile was discussed based on mechanical aspect of CMP. Using the model, we also investigated the effect of variable rotational speeds of wafer and pad, and of large particles on WIWNU and scratch growth. It was shown that the presence of even a small portion of large particles can deteriorate the WIWNU significantly and also lead to more scratches. Furthermore, it was shown that the in-situ conditioning improves the uniformity of the polished wafers. Furthermore, a combined experimental and computational study of fibrous filters for removal of larger abrasive particles from aqueous dispersions, essential to minimize defects during chemical mechanical polishing, was performed. Dilute aqueous

  17. Experiments on steady state particle control in Tore Supra and DIII-D

    SciTech Connect

    Mioduszewski, P.K.; Hogan, J.T.; Owen, L.W.

    1994-12-31

    Particle control is playing an increasingly important role in tokamak plasma performance. The present paper discusses particle control of hydrogen/deuterium by wall pumping on graphite or carbonized surfaces, as well as by external exhaust with pumped limiters and pumped divertors. Wall pumping is ultimately a transient effect and by itself not suitable for steady state particle exhaust. Therefore, external exhaust techniques with pumped divertors and limiters are being developed. How wall pumping phenomena interact and correlate with these inherently steady state, external exhaust techniques, is not well known to date. In the present paper, the processes involved in wall pumping and in external pumping are investigated in an attempt to evaluate the effect of external exhaust on wall pumping. Some of the key elements of this analysis are: (1) charge-exchange fluxes to the wall play a crucial role in the core-wall particle dynamics, (2) the recycling fluxes of thermal molecules have a high probability of ionization in the scrape-off layer, (3) thermal particles originating from the wall, which are ionized within the scrape-off layer, can be directly exhausted, thus providing a direct path between wall and exhaust which can be used to control the wall inventory. This way, the wall can be kept in a continuous pumping state in the sense that it continuously absorbs energetic particles and releases thermal molecules which are then removed by the external exhaust mechanism. While most of the ingredients of this analysis have been observed individually before, the present evaluation is an attempt to correlate effects of wall recycling and external exhaust.

  18. Mitigation of soiling losses in solar collectors: Removal of surface-adhered dust particles using an electrodynamic screen

    NASA Astrophysics Data System (ADS)

    Sayyah, Arash

    Particulate contamination of the optical surfaces of solar collectors, often called "soiling", can have a significant deteriorating impact on energy yield due to the absorption and scattering of incident light. Soiling has more destructive effect on concentrated solar systems than on flat-plate photovoltaic panels, as the former are incapable of converting scattered sunlight. The first part of this thesis deals with the soiling losses of flat-plate photovoltaic (PV), concentrated solar power (CSP), and concentrated photovoltaic (CPV) systems in operation in several regions of the world. Influential parameters in dust accumulation losses, as well as different cleaning mechanisms in pursuit of restoring the efficiency of soiled systems, have been thoroughly investigated. In lieu of the most commonly-practiced manual cleaning method of using high-pressure water jets, the concept of automatic dust removal using the electrostatic forces of electrodynamic screen (EDS) technology is in a developmental stage and on its way toward commercialization. This thesis provides comprehensive analytical solutions for the electric potential and electric field distribution in EDS devices having different configurations. Numerical simulations developed using finite element analysis (FEA) software have corroborated the analytical solutions which can easily be embedded into software programs for particle trajectory simulations while also providing flexibility and generality in the study on the effect of different parameters of the EDS on the electric field and ensuing dust-removal performance. Evaluation and comparison of different repelling and attracting forces exerted on dust particles is of utmost importance to a detailed analysis of EDS performance in dust removal. Hence, the balance of electrostatic and adhesion forces, including van der Waals and capillary forces, have received significant attention in this dissertation. Furthermore, different numerical analyses have been

  19. Magnetic microswimmers: Controlling particle approach through magnetic and hydrodynamic interaction

    NASA Astrophysics Data System (ADS)

    Meshkati, Farshad; Cheang, U. Kei; Kim, Minjun; Fu, Henry

    2015-11-01

    We investigate magnetic microswimmers actuated by a rotating magnetic field that may be useful for drug delivery, micro-surgery, or diagnostics in human body. For modular swimmers, assembly and disassembly requires understanding the interactions between the swimmer and other modules in the fluid. Here, we discuss possible mechanisms for a frequency-dependent attraction/repulsion between a three-bead, achiral swimmer and other magnetic particles, which represent modular assembly elements. We first investigate the hydrodynamic interaction between a swimmer and nearby particle by studying the Lagrangian trajectories in the vicinity of the swimmer. Then we show that the magnetic forces can be attractive or repulsive depending on the spatial arrangement of the swimmer and particle, with a magnitude that decreases with increasing frequency. Combining magnetic and hydrodynamic effects allows us to understand the overall behavior of magnetic particles near the swimmer. Interestingly, we find that the frequency of rotation can be used to control when the particle can closely approach the swimmer, with potential application to assembly.

  20. Controlled synthesis of ferromagnetic MnSe x particles

    NASA Astrophysics Data System (ADS)

    Sun, Junjie; Li, Chao; Chen, Duo; Kang, Shishou; Liu, Guolei; Yu, Shuyun; Han, Guangbing; Mei, Liangmo

    2016-10-01

    The MnSe x (x = 1,2) nanoparticles were synthesized under hydrothermal condition, by reaction of the reduced selenium and Mn2+ ion in the presence of hydrazine and acetic acid. By precisely controlling the pH value of the solution, a series of MnSe x particles were synthesized. The structure and morphology of as-prepared particles were examined with x-ray diffractometer (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The average sizes of as-prepared particles varied from nanoscale to microscale with pH value increase. Furthermore, the nucleation and growth mechanism associated with pH values were discussed, which can be applied to the hydrothermal synthesis of metal chalcogenide in general. Finally, the optical and magnetic properties of as-prepared particles were measured. All as-made particles exhibit a ferromagnetic behavior with low coercivity and remanence at room temperature. Project supported by the National Basic Research Program of China (Grant No. 2015CB921502), the National Natural Science Foundation of China (Grant Nos. 11474184 and 11627805), the 111 Project (Grant No. B13029), and the Fundamental Research Funds of Shandong University, China.

  1. Dynamic self-assembly and control of microfluidic particle crystals

    PubMed Central

    Lee, Wonhee; Amini, Hamed; Stone, Howard A.; Di Carlo, Dino

    2010-01-01

    Engineered two-phase microfluidic systems have recently shown promise for computation, encryption, and biological processing. For many of these systems, complex control of dispersed-phase frequency and switching is enabled by nonlinearities associated with interfacial stresses. Introducing nonlinearity associated with fluid inertia has recently been identified as an easy to implement strategy to control two-phase (solid-liquid) microscale flows. By taking advantage of inertial effects we demonstrate controllable self-assembling particle systems, uncover dynamics suggesting a unique mechanism of dynamic self-assembly, and establish a framework for engineering microfluidic structures with the possibility of spatial frequency filtering. Focusing on the dynamics of the particle–particle interactions reveals a mechanism for the dynamic self-assembly process; inertial lift forces and a parabolic flow field act together to stabilize interparticle spacings that otherwise would diverge to infinity due to viscous disturbance flows. The interplay of the repulsive viscous interaction and inertial lift also allow us to design and implement microfluidic structures that irreversibly change interparticle spacing, similar to a low-pass filter. Although often not considered at the microscale, nonlinearity due to inertia can provide a platform for high-throughput passive control of particle positions in all directions, which will be useful for applications in flow cytometry, tissue engineering, and metamaterial synthesis. PMID:21149674

  2. Controlled propulsion and separation of helical particles at the nanoscale.

    PubMed

    Alcanzare, Maria Michiko T; Thakore, Vaibhav; Ollila, Santtu T T; Karttunen, Mikko; Ala-Nissila, Tapio

    2017-02-22

    Controlling the motion of nano and microscale objects in a fluid environment is a key factor in designing optimized tiny machines that perform mechanical tasks such as transport of drugs or genetic material in cells, fluid mixing to accelerate chemical reactions, and cargo transport in microfluidic chips. Directed motion is made possible by the coupled translational and rotational motion of asymmetric particles. A current challenge in achieving directed and controlled motion at the nanoscale lies in overcoming random Brownian motion due to thermal fluctuations in the fluid. We use a hybrid lattice-Boltzmann molecular dynamics method with full hydrodynamic interactions and thermal fluctuations to demonstrate that controlled propulsion of individual nanohelices in an aqueous environment is possible. We optimize the propulsion velocity and the efficiency of externally driven nanohelices. We quantify the importance of the thermal effects on the directed motion by calculating the Péclet number for various shapes, number of turns and pitch lengths of the helices. Consistent with the experimental microscale separation of chiral objects, our results indicate that in the presence of thermal fluctuations at Péclet numbers >10, chiral particles follow the direction of propagation according to its handedness and the direction of the applied torque making separation of chiral particles possible at the nanoscale. Our results provide criteria for the design and control of helical machines at the nanoscale.

  3. Effects of Varying Particle Sizes and Different Types of LDH-Modified Anthracite in Simulated Test Columns for Phosphorous Removal

    PubMed Central

    Zhang, Xiangling; Chen, Qiaozhen; Guo, Lu; Huang, Hualing; Ruan, Chongying

    2015-01-01

    A comparative study was carried out for the removal of phosphorus in simulated unplanted vertical-flow constructed wetlands with different layered double hydroxide (LDHs) coated anthracite substrates. Three particle sizes of anthracites were selected and modified separately with nine kinds of LDH coating. The simulated substrates test columns loaded with the original and modified anthracites were constructed to treat the contaminated water. For the medium and large particle size modified anthracite substrates, the purification effects of total phosphorus, total dissolved phosphorus and phosphate were improved by various degrees, and the purification effect of the medium particle size anthracite is better than that of the large size one. The medium size anthracite modified by ZnCo-LDHs had optimal performance with average removal efficiencies of total phosphorus, total dissolved phosphorus and phosphate reaching 95%, 95% and 98%, respectively. The maximum adsorption capacity on ZnCo-LDHs and ZnAl-LDHs modified medium sizes anthracites were 65.79 (mg/kg) and 48.78 (mg/kg), respectively. In comparison, the small size anthracite is not suitable for LDHs modification. PMID:26086702

  4. Effects of Varying Particle Sizes and Different Types of LDH-Modified Anthracite in Simulated Test Columns for Phosphorous Removal.

    PubMed

    Zhang, Xiangling; Chen, Qiaozhen; Guo, Lu; Huang, Hualing; Ruan, Chongying

    2015-06-16

    A comparative study was carried out for the removal of phosphorus in simulated unplanted vertical-flow constructed wetlands with different layered double hydroxide (LDHs) coated anthracite substrates. Three particle sizes of anthracites were selected and modified separately with nine kinds of LDH coating. The simulated substrates test columns loaded with the original and modified anthracites were constructed to treat the contaminated water. For the medium and large particle size modified anthracite substrates, the purification effects of total phosphorus, total dissolved phosphorus and phosphate were improved by various degrees, and the purification effect of the medium particle size anthracite is better than that of the large size one. The medium size anthracite modified by ZnCo-LDHs had optimal performance with average removal efficiencies of total phosphorus, total dissolved phosphorus and phosphate reaching 95%, 95% and 98%, respectively. The maximum adsorption capacity on ZnCo-LDHs and ZnAl-LDHs modified medium sizes anthracites were 65.79 (mg/kg) and 48.78 (mg/kg), respectively. In comparison, the small size anthracite is not suitable for LDHs modification.

  5. Development of an ash particle deposition model considering build-up and removal mechanisms

    SciTech Connect

    Kjell Strandstroem; Christian Muellera; Mikko Hupa

    2007-12-15

    Slagging and fouling on heat exchanger surfaces in power boilers fired with fossil fuels and fuel mixtures has a significant influence on boiler efficiency and availability. Mathematical modelling has long been considered a suitable method to assist boiler operators to determine optimized operating conditions for an existing furnace. The ultimate goal in ash deposition prediction is hereby the determination of the total amount of material deposited and hence the determination of the total reduction in efficiency. Depending on the fuels fired the total deposited mass is a combination of ash particle deposition and ash particle erosion due to non-sticky particles. The novel ash particle deposition model presented in this work considers deposition of sticky ash particles, cleansing of deposit by non-sticky sand particles and sticking of sand due to contact with sticky ash. The steady-state modelling results for the total amount of ash deposited on the deposition probe of an entrained flow reactor presented in this work agree well with the experimental data. Only at very high fractions of sand added as non-sticky material, a significant influence of the sand on the overall mass deposited was found. Since the model considers sticking of non-sticking sand due to contact with sticky ash, the fraction of sand deposited on the probe was especially studied. Using a correction factor to consider the influence of operating time on the steady-state simulations led to good agreement between simulations and experimental data. 12 refs., 10 figs.

  6. Experimental Study on Ultrafine Particle Removal Performance of Portable Air Cleaners with Different Filters in an Office Room

    PubMed Central

    Ma, Huan; Shen, Henggen; Shui, Tiantian; Li, Qing; Zhou, Liuke

    2016-01-01

    Size- and time-dependent aerodynamic behaviors of indoor particles, including PM1.0, were evaluated in a school office in order to test the performance of air-cleaning devices using different filters. In-situ real-time measurements were taken using an optical particle counter. The filtration characteristics of filter media, including single-pass efficiency, volume and effectiveness, were evaluated and analyzed. The electret filter (EE) medium shows better initial removal efficiency than the high efficiency (HE) medium in the 0.3–3.5 μm particle size range, while under the same face velocity, the filtration resistance of the HE medium is several times higher than that of the EE medium. During service life testing, the efficiency of the EE medium decreased to 60% with a total purifying air flow of 25 × 104 m3/m2. The resistance curve rose slightly before the efficiency reached the bottom, and then increased almost exponentially. The single-pass efficiency of portable air cleaner (PAC) with the pre-filter (PR) or the active carbon granule filter (CF) was relatively poor. While PAC with the pre-filter and the high efficiency filter (PR&HE) showed maximum single-pass efficiency for PM1.0 (88.6%), PAC with the HE was the most effective at removing PM1.0. The enhancement of PR with HE and electret filters augmented the single-pass efficiency, but lessened the airflow rate and effectiveness. Combined with PR, the decay constant of large-sized particles could be greater than for PACs without PR. Without regard to the lifetime, the electret filters performed better with respect to resource saving and purification improvement. A most penetrating particle size range (MPPS: 0.4–0.65 μm) exists in both HE and electret filters; the MPPS tends to become larger after HE and electret filters are combined with PR. These results serve to provide a better understanding of the indoor particle removal performance of PACs when combined with different kinds of filters in school

  7. Decay heat removal from a Particle Bed Reactor Nuclear Thermal Rocket engine

    NASA Astrophysics Data System (ADS)

    Gustafson, Eric

    1993-06-01

    Nuclear Thermal Rockets used in propulsion systems for planetary exploration will generate significant amounts of heat following normal engine shutdown due to the buildup of and decay of radioactive fission products. The amount of energy that is generated as decay heat is approximately 2-5 percent of the energy released during nominal operation. Various schemes are possible for removing this heat, including using primary coolant (hydrogen) to cool the reactor. Depending on the amount of coolant required, this may result in a large weight penalty for the mission. This paper quantifies the amount of decay heat that must be removed from the engine, shows the resulting impact on the vehicle design for particular missions, and examines possible approaches for reducing the amount of coolant required for decay heat removal. The costs and benefits of these schemes will be shown for several different missions. The missions that will be considered include both manned Mars missions and unmanned planetary exploration missions.

  8. SEMICONDUCTOR TECHNOLOGY: Material removal rate in chemical-mechanical polishing of wafers based on particle trajectories

    NASA Astrophysics Data System (ADS)

    Jianxiu, Su; Xiqu, Chen; Jiaxi, Du; Renke, Kang

    2010-05-01

    Distribution forms of abrasives in the chemical mechanical polishing (CMP) process are analyzed based on experimental results. Then the relationships between the wafer, the abrasive and the polishing pad are analyzed based on kinematics and contact mechanics. According to the track length of abrasives on the wafer surface, the relationships between the material removal rate and the polishing velocity are obtained. The analysis results are in accord with the experimental results. The conclusion provides a theoretical guide for further understanding the material removal mechanism of wafers in CMP.

  9. Enhancement removal of tartrazine dye using HCl-doped polyaniline and TiO2-decorated PANI particles

    NASA Astrophysics Data System (ADS)

    Elsayed, M. A.; Gobara, Mohamed

    2016-08-01

    HCl-doped polyaniline (HCl-PANI) and titanium dioxide decorated with polyaniline (TiO2-decorated PANI) with different TiO2:PANI ratios were chemically prepared and utilized for the removal of tartrazine (TZ) dye from a synthetic aqueous solution. The mechanism of preparation of the sample suggested that aniline was adsorbed on the TiO2 surface before the polymerization process took place. Samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction. The results showed that HCl-PANI and TiO2-decorated PANI have an amorphous structure. The thermal stability of the prepared samples was characterized using thermo-gravimetric (TG) analysis. HCl-PANI is stable up to 200 °C and the relative weight per cent of PANI in the TiO2-decorated PANI was 20, 25, 40 and 45%. The removal activity of TiO2-decorated PANI via TZ azo dye was investigated under UV light irradiations and compared with HCl-PANI and TiO2 particles. The results indicated the superiority of the TiO2-decorated PANI over pure HCl-PANI and TiO2. However, the excessive PANI percentage tends to form a relatively thick layer, and even aggregates on the surface of TiO2. This hinders the migration of excited electrons from the outer PANI layer to the inner TiO2 particles, which consequently leads to a decrease in the removal efficiency. A possible mechanism for the removal oxidative degradation is also mentioned.

  10. Changes in Fish Habitat And Demography Following Dam Removal in a Headwater Catchment: Linking Geomorphic, Hydrologic, and Ecological Controls

    NASA Astrophysics Data System (ADS)

    Magilligan, F. J.; Nislow, K. H.; Kynard, B.; Hackman, A. M.

    2013-12-01

    Dam removal is a major component of river restoration efforts in New England. More than 115 dams have been removed in the past few decades with the goal to restore historical runs of diadromous fish. Taking advantage of the Fall 2012 removal of the 5 m high Pelham Dam in central Massachusetts, we sampled pre- and post-removal geomorphic parameters (18 cross-sections along a 800 m reach, Wolman pebble counts, embeddedness surveys, and detailed long profiles) in Amethyst Brook (23 km2) an upstream tributary of the Fort River drainage. These geomorphic assessments were combined with detailed quantitative electrofishing surveys of stream fish richness and abundance above and below the dam site and throughout the watershed; genetic assignments and stable isotope analysis to determine population connectivity; and visual surveys of native anadromous Sea lamprey (Petromyzon marinus) nest sites. Post-removal assessments were complicated by two events: (1) upstream knickpoint migration exhumed an older (ca. early 19th century) intact wooden crib dam ~ 120 m upstream of the former stone dam, and (2) the occurrence of a 10-20 yr RI flood 6 months after removal which caused further upstream incision and downstream aggradation. Geomorphic results document that all 11 cross-sections downstream of the former dam fined significantly with typical reductions of 30-60% in mean particle size. This has major implications for Sea lamprey that require gravel for spawning which was largely absent downstream of the former sediment-trapping dam. This fining was associated with downstream bed aggradation, reflecting the new, post-removal flux of material. Similarly, post-removal, but pre-flood, bed surveys indicate ~ 2 m of incision had migrated 25 m upstream of the former reservoir before encountering the exhumed dam, which now acts as the new grade control, limiting progressive headcutting. The combination of changes in channel bed sedimentology, the occurrence of a large magnitude flood

  11. Removal of lead and cadmium ions from aqueous solution by adsorption onto micro-particles of dry plants.

    PubMed

    Benhima, H; Chiban, M; Sinan, F; Seta, P; Persin, M

    2008-01-15

    In the present work, Pb(II) and Cd(II) ion adsorption onto inert organic matter (IOM) obtained from ground dried plants: Euphorbia echinus, Launea arborescens, Senecio anthophorbium growing in semi-arid zones of Morocco and Carpobrotus edulis as the Mediterranean plant has been studied. A suspension of plant deroed micro-particles adsorbs lead and cadmium present as ionic species, with a higher affinity for Pb(II). The kinetics and the maximum capacity adsorption depend on the type of plant as well as on the metal ions (atomic weight, ionic radius and electronegativity). The adsorption process is affected by various parameters such as contact time, solution volume to mass of plant particles ratio (m/V), particle size, solution pH and metal concentration. A dose of 25 g/l of adsorbent was optimal to obtain maximum adsorption of both metal ions. The maximum metal uptake was obtained with particles of organic matter of <50 microm. As to classical ionic adsorption phenomena, the adsorption of both metal ions increases with the increase of the initial concentration in the solution. For the two metal cations, the uptake efficiency of the studied plants ranged from: C. edulis>E. echinus>S. anthophorbium>L. arborescens, however, the differences are rather small. Two different waste water types (domestic and industrial) were tested and good results were obtained for removal of Pb(II) and Cd(II) at more than 90%. The removal of the metal and mineral ions waste water was observed for PO(4)(3-) at 88%, for NO(3)(-) at 96.5% and for metal ions (Pb(II), Cd(II), Cu(II) and Zn(II)) at about 100%, using IOM as absorbent.

  12. Particle Size Control of Polyethylene Glycol Coated Fe Nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivasan, B.; Bonder, M. J.; Zhang, Y.; Gallo, D.; Hadjipanayis, G. C.

    2006-03-01

    Recent interest in Fe nanoparticles with high magnetization is driven by their potential use in biomedical applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia treatment of cancer. This study looks at the use of a polyethylene glycol (PEG) solution to mediate the particle size and therefore control the coercivity of the resulting nanoparticles. Iron nanoparticles were synthesized using an aqueous sodium borohydride reduction of ferrous chloride by a simultaneous introduction of reagents in a Y- junction. The resulting product was collected in a vessel containing a 15 mg/ml carboxyl terminated polyethylene glycol (cPEG) in ethyl alcohol solution located under the Y junction. By varying the length of tubing below the Y junction, the particle size was varied from 5-25 nm. X-ray diffraction data indicates the presence of either amorphous Fe-B or crystalline alpha Fe, depending on the molar ratio of reagents. Magnetic measurements indicate the particles are ferromagnetic with values of coercivity ranging from 200-500 Oe and a saturation magnetization in range of 70-110 emu/g. The XRD shows that the particles are not affected by the polymer coating.

  13. Experimental investigation on removal of suspended particles from water using flax fibre geotextiles.

    PubMed

    Abbar, Bouamama; Alem, Abdellah; Pantet, Anne; Marcotte, Stéphane; Ahfir, Nasre-Dine; Duriatti, Davy

    2017-02-05

    Natural geotextiles are increasingly used in geotechnical applications such as bank protection and short-term soil reinforcement. This study aimed to highlight the behaviour of natural flax fibre geotextiles towards the retention of suspended particles (SP) present in urban runoff and often polluted. Indeed, it is well known that a large fraction of the heavy metals are often associated with the SP. Long-term filtration tests were performed on four laboratory filter designs. The objective was to study the influence of a nonwoven flax fibre geotextiles on SP transfer through a sandy porous media under saturated conditions. The experiments consisted of injecting SP in a column filled with sand with and without flax fibre geotextiles at a constant flow rate. The results showed that nonwoven flax fibre geotextiles can increase flow homogeneity. Retention efficiency of SP at column scale as well as spatial deposition profile was modified by the presence of geotextile. The use of flax fibre geotextiles increases considerably the durability of the filtration system. Particle size analysis of the particles retained in the sand medium and in geotextiles shows that the coarser particles are mainly deposited at the entrance of the column, and in the geotextiles.

  14. Controlling temperature in magnetic hyperthermia with low Curie temperature particles

    NASA Astrophysics Data System (ADS)

    Astefanoaei, Iordana; Dumitru, Ioan; Chiriac, Horia; Stancu, Alexandru

    2014-05-01

    Hyperthermia induced by the heating of magnetic particles (MPs) in alternating magnetic field receives a considerable attention in cancer therapy. An interesting development in the studies dedicated to magnetically based hyperthermia is the possibility to control the temperature using MPs with selective magnetic absorption properties. This paper analyzes the temperature field determined by the heating of MPs having low Curie temperature (a FeCrNbB particulate system) injected within a malignant tissue, subjected to an ac magnetic field. The temperature evolution within healthy and tumor tissues was analyzed by finite element method simulations in a thermo-fluid model. The cooling effect produced by blood flowing in blood vessels was considered. This effect is intensified at the increase of blood velocity. The FeCrNbB particles, having the Curie temperature close to the therapeutic range, transfer the heat more homogeneous in the tumor keeping the temperature within the therapeutic range in whole tumor volume. Having the possibility to automatically control the temperature within a tumor, these particle type opens new research horizons in the magnetic hyperthermia.

  15. PARTICLE ACCELERATOR AND METHOD OF CONTROLLING THE TEMPERATURE THEREOF

    DOEpatents

    Neal, R.B.; Gallagher, W.J.

    1960-10-11

    A method and means for controlling the temperature of a particle accelerator and more particularly to the maintenance of a constant and uniform temperature throughout a particle accelerator is offered. The novel feature of the invention resides in the provision of two individual heating applications to the accelerator structure. The first heating application provided is substantially a duplication of the accelerator heat created from energization, this first application being employed only when the accelerator is de-energized thereby maintaining the accelerator temperature constant with regard to time whether the accelerator is energized or not. The second heating application provided is designed to add to either the first application or energization heat in a manner to create the same uniform temperature throughout all portions of the accelerator.

  16. Removal of Cu(II) from aqueous solution using synthetic poly(catechol-diethylenetriamine-p-phenylenediamine) particles.

    PubMed

    Liu, Qiang; Liu, Qinze; Ruan, Zining; Chang, Xiaoqing; Yao, Jinshui

    2016-07-01

    A novel poly(catechol-diethylenetriamine-pphenylenediamine)(PCEA) adsorbent was synthesized in methanol, with chelating groups supplied by catechol and diethylenetriamine, which showed a strong removal performance and efficient adsorption toward Cu(II) ions in aqueous solution. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Besides, factors such as adsorbent dosage, pH, initial ionic and metal concentrations, contact time, and temperature on the adsorption of Cu(II) were studied. The data revealed that the adsorption followed a pseudo-second order kinetic model and the adsorption rate was influenced by the intra-particle diffusion. Furthermore, the adsorption process followed the Langmuir isotherm model, and the maximum adsorption capacity (Qm) was 44.2mg/g at 298K in simulated wastewater. The value of ΔG (kJ/mol) and ΔH (kJ/mol) also demonstrated that the adsorption process was spontaneous and endothermic. Studies revealed that PCEA particles were powerful and stable for the removal of Cu(II) in water, and it could be directly applied to the Cu(II)-contaminated water.

  17. Crystalline structure of ceria particles controlled by the oxygen partial pressure and STI CMP performances.

    PubMed

    Kim, Ye-Hwan; Kim, Sang-Kyun; Kim, Namsoo; Park, Jea-Gun; Paik, Ungyu

    2008-09-01

    The effect of the crystalline structures of nano-sized ceria particles on shallow trench isolation (STI) chemical mechanical planarization (CMP) performance was investigated. The ceria particles were synthesized via a solid-state displacement reaction method, and their crystalline structure was controlled by regulating the oxygen partial pressure at the reaction site on the precursor. The crystalline structures of ceria particles were analyzed by the high-resolution TEM nano-beam diffraction pattern. In a calcination process with a high oxygen concentration, the synthesized ceria particles had a cubic fluorite structure (CeO(2)), because of the decarbonation of the cerium precursor. However, a low oxygen concentration results in a hexagonal phase cerium oxide (Ce(2)O(3)) rather than the cubic phase due to the insufficient oxidation of Ce(3+) to Ce(4+). In the STI CMP evaluation, the ceria slurry prepared with the cubic CeO(2) shows enhanced performances of the oxide-to-nitride removal selectivity.

  18. Noise Removal with Maintained Spatial Resolution in Raman Images of Cells Exposed to Submicron Polystyrene Particles

    PubMed Central

    Ahlinder, Linnea; Wiklund Lindström, Susanne; Lejon, Christian; Geladi, Paul; Österlund, Lars

    2016-01-01

    The biodistribution of 300 nm polystyrene particles in A549 lung epithelial cells has been studied with confocal Raman spectroscopy. This is a label-free method in which particles and cells can be imaged without using dyes or fluorescent labels. The main drawback with Raman imaging is the comparatively low spatial resolution, which is aggravated in heterogeneous systems such as biological samples, which in addition often require long measurement times because of their weak Raman signal. Long measurement times may however induce laser-induced damage. In this study we use a super-resolution algorithm with Tikhonov regularization, intended to improve the image quality without demanding an increased number of collected pixels. Images of cells exposed to polystyrene particles have been acquired with two different step lengths, i.e., the distance between pixels, and compared to each other and to corresponding images treated with the super-resolution algorithm. It is shown that the resolution after application of super-resolution algorithms is not significantly improved compared to the theoretical limit for optical microscopy. However, to reduce noise and artefacts in the hyperspectral Raman images while maintaining the spatial resolution, we show that it is advantageous to use short mapping step lengths and super-resolution algorithms with appropriate regularization. The proposed methodology should be generally applicable for Raman imaging of biological samples and other photo-sensitive samples.

  19. Effective removal of Ni(II) from aqueous solutions by modification of nano particles of clinoptilolite with dimethylglyoxime.

    PubMed

    Nezamzadeh-Ejhieh, Alireza; Kabiri-Samani, Mehdi

    2013-09-15

    In this work an Iranian natural clinoptilolite tuff was pre-treated and changed to the micro (MCP) and nano (NCP) particles by mechanical method. Modification of micro and nano particles and also their Ni-exchanged forms were done by dimethylglyoxime (DMG). The raw and modified samples were characterized by XRD, FT-IR, SEM, BET, TG-DTG and energy dispersive analysis X-ray spectroscopy (EDAX). Removal of Ni(II) by modified and unmodified samples was investigated in batch procedure. It was found that NCP-DMG has higher capacity for removal of Ni(II). The effects of analytical parameters such as pH, dose of DMG, concentration of nickel solution, contact time and selectivity were studied and the optimal operation parameters were found as follows: pHPZC: 7.6, CNi(II): 0.01 M, contact time: 360 min and DMG dosage: 5mM. The results of selectivity experiments showed that the modified zeolite has a good selectivity for nickel in the presence of different multivalent cations. Langmuir and Freundlich isotherm models were adopted to describe the adsorption isotherms. Adsorption isotherms of Ni(II) ions could be best modelled by Langmuir equation, that indicate the monolayer sorption of Ni(II). Comparison of two kinetic models indicates that the adsorption kinetic can be well described by the pseudo-second-order rate equation that indicates that the rate limiting step for the process involves chemical reaction. The negative ΔH and ΔG indicate an exothermic and spontaneously process. The negative ΔS indicates that the adsorption of nickel cations from solution occurs with lower amount ion replacement, thus chemisorptions due to complex formation are dominant process in nickel removal.

  20. The effectiveness of faecal removal methods of pasture management to control the cyathostomin burden of donkeys

    PubMed Central

    2014-01-01

    Background The level of anthelmintic resistance within some cyathostomin parasite populations has increased to the level where sole reliance on anthelmintic-based control protocols is not possible. Management-based nematode control methods, including removal of faeces from pasture, are widely recommended for use in association with a reduction in anthelmintic use to reduce selection pressure for drug resistance; however, very little work has been performed to quantitatively assess the effectiveness of such methods. Methods We analysed data obtained from 345 donkeys at The Donkey Sanctuary (Devon, UK), managed under three different pasture management techniques, to investigate the effectiveness of faeces removal in strongyle control in equids. The management groups were as follows: no removal of faeces from pasture, manual, twice-weekly removal of faeces from pasture and automatic, twice-weekly removal of faeces from pasture (using a mechanical pasture sweeper). From turn-out onto pasture in May, monthly faecal egg counts were obtained for each donkey and the dataset subjected to an auto regressive moving average model. Results There was little to no difference in faecal egg counts between the two methods of faecal removal; both resulted in significantly improved cyathostomin control compared to the results obtained from the donkeys that grazed pasture from which there was no faecal removal. Conclusions This study represents a valuable and unique assessment of the effectiveness of the removal of equine faeces from pasture, and provides an evidence base from which to advocate twice-weekly removal of faeces from pasture as an adjunct for equid nematode control. Widespread adoption of this practice could substantially reduce anthelmintic usage, and hence reduce selection pressure for nematode resistance to the currently effective anthelmintic products. PMID:24460700

  1. Synthesis, modification and graft polymerization of magnetic nano particles for PAH removal in contaminated water

    PubMed Central

    2014-01-01

    Magnetic nanoparticles (MNPs) were modified with 3-Mercaptopropytrimethoxysiline (MPTMS) and grafted with allyl glycidyl ether for coupling with beta naphtol as a method to form a novel nano-adsorbent to remove two poly aromatic hydrocarbons (PAHs) from contaminated water. The modified MNPs were characterized by transmission electron microscopy, infrared spectroscopy and thermogravimetric analysis. Results showed that the modified MNPs enhanced the process of adsorption. Tests were done on the adsorption capacity of the two PAHs on grafted MNPs; factors applied to the tests were temperature, contact time, pH, salinity and initial concentration of PAHs. Results revealed that adsorption equilibrium was achieved in 10 min, and the maximum adsorption capacity was determined as 4.15 mg/g at pH = 7.0 and 20°C. The equilibrium adsorption data of the two PAHs by the modified MNPs were analyzed by Langmuir, Freundlich and Temkin models. Equilibrium adsorption data was determined from the Langmuir, Freundlich and Temkin constants from tests under conditions of pH = 7 and temperature 20°C. Analysis of the adsorption-desorption process indicated that the modified MNPs had a high level of stability and good reusability. Magnetic separation in these tests was fast and this shows that the modified MNPs have great potential to be used as a new adsorbent for the two PAHs removal from contaminated water in water treatment. PMID:25101170

  2. Evaluation of riverbank infiltration as a process for removing particles and DBP precursors

    SciTech Connect

    Wang, J.; Smith, J.; Dooley, L.

    1996-11-01

    Recent outbreaks of waterborne disease attributed to Cryptosporidium in drinking water have raised serious concerns over the effectiveness of conventional water treatment processes to produce safe drinking water supplies. Past studies have shown Cryptosporidium and Giardia to be prevalent in surface water supplies, particularly in urban-impacted surface waters such as the Ohio River which Louisville Water Company (LWC) treatment facilities utilize as their source water. Such indications of the widespread occurrence of these pathogens in source waters underscore the need for the water supply industry to evaluate alternative technologies to conventional water treatment to reduce the risk of waterborne disease occurrence. Public health concerns, shared by the water utility industry, drinking water regulators, and public water supply consumers alike, prompted the US Environmental Protection Agency (USEPA) to propose regulatory action aimed at balancing the risks of microbial disease occurrence and the health risks associated with exposure to potentially harmful compounds formed during drinking water disinfection. In pursuit of this objective, USEPA proposed the Enhanced Surface Water Treatment Rule (ESWTR) to improve public water supply treatment performance for microbial removal and proposed the Disinfectant/Disinfection Byproduct (D/DBP) Rule to reduce DBP exposure levels. As a consequence of these rules, many water utilities will be tasked with the challenge of developing treatment capabilities which improve microbial removal performance while minimizing the production of DBPs.

  3. New mass measurement method of aerosol particle using vibrating probe particle controlled by radiation pressure

    NASA Astrophysics Data System (ADS)

    Hariyama, Tatsuo; Takaya, Yasuhiro; Miyoshi, Takashi

    2005-11-01

    Aerosol particles with sub-micro meter size inhaled into respiratory systems cause serious damage to human body. In order to evaluate the health effects of the particles, classification methods of the particles with size and mass are needed. Several measurement methods of the particle size are established. However, conventional mass measurement methods are not enough to measure the particles with sub- pico gram. We propose a new mass measurement method of the aerosol particles based on laser trapping. In this method, an optically trapped silica particle is used as a measuring probe particle. The probe particle is trapped at a beam waist of the focused laser light and is forced to vibrate by deflecting the beam waist using AOD. The vibrating probe particle has a resonance frequency because it is governed by the spring-mass-damper system. When an aerosol particle is attached to the probe particle, the resonance frequency shifts according to the increase of the total mass. The mass of the aerosol particle can be measured from the shift of the resonance frequency. Experimentally, it is confirmed that the probe particle is governed by the spring-mass-damper system and has a resonance frequency. When a silica fine particle of 3pg in mass used as an aerosol particle is attached to the probe particle, the resonance frequency shift occurs as expected in the dynamic system and the fine particle mass can be measured based on the proposed method.

  4. Coupling Fe0 nano particles with living and dead Azolla filicoloides to improve removal of methylene blue from aqueous solution

    NASA Astrophysics Data System (ADS)

    Rakhshaee, Roohan

    2015-11-01

    Fe0 nano particles (FNPs) were connected to the cell wall of the dead and living Azolla filicoloides as an aquatic fern, individually. FNPs mean size was decreased due to the stabilization, especially using the living one. It was compared the results of X-ray photoelectron spectroscopy (XPS), saturation magnetization (Ms), zeta potential (ZP) and thermal analysis (DSC and TGA) of the dead and living Azolla connected to FNPs, and also the findings of potentiometric titration (PT) of the cell wall's pectin of the dead and living Azolla. It was confirmed (by XRD and XPS) that Fe0 nano particles when were connected to the living Azolla did not produce Fe3O4 due to oxidation unlike the bare FNPs and the connected form to the dead Azolla, by reason of the more stabilization (more surface protection) of nano iron particles after connecting to the living Azolla. To adsorb methylene blue by these agents at the optimum pre-treatment pH 10 and adsorption pH 8, the parameters of equilibrium sorption, rate constant of second-order sorption and activation energy were obtained as: living Azolla-FNPs > dead Azolla-FNPs > FNPs > dead Azolla, while, their thermodynamic parameters (ΔG°, ΔH° and ΔS°) had the reverse arrangement. It was also studied the various factors rule such as photoperiod and the presence of heavy metals on the living Azolla growth coupled with FNPs and its MB removal ability.

  5. Wall conditioning and particle control in Extrap T2

    NASA Astrophysics Data System (ADS)

    Bergsåker, H.; Larsson, D.; Brunsell, P.; Möller, A.; Tramontin, L.

    1997-02-01

    The Extrap T2 reversed field pinch experiment is operated with the former OHTE vacuum vessel, of dimensions R = 1.24 m and a = 0.18 m and with a complete graphite liner. It is shown that a rudimentary density control can be achieved by means of frequent helium glow discharge conditioning of the wall. The standard He-GDC is well characterized and reproducible. The trapping and release of hydrogen and impurities at the wall surfaces have been studied by mass spectrometry and surface analysis. The shot to shot particle exchange between wall and plasma can be approximately accounted for.

  6. Induction plasma calcining of pigment particles for thermal control coatings

    NASA Technical Reports Server (NTRS)

    Farley, E. P.

    1971-01-01

    Induction plasma heating techniques were studied for calcining zinc orthotitanate particles for use in thermal control coatings. Previous studies indicated that the optimum calcining temperature is between 1400 and 1750 C. An intermediate temperature (1670 C) was chosen as a reference point for running a temperature series at the reference point and 220 C on both sides. The effect of varying chamber temperature on the reflectance spectra, before and after vacuum UV irradiation, is presented. The correlation between Zn2Ti04 paramagnetic resonance activity and its susceptibility to vacuum UV damage is discussed.

  7. Optically controlled grippers for manipulating micron-sized particles

    NASA Astrophysics Data System (ADS)

    Gibson, Graham; Barron, Louise; Beck, Fiona; Whyte, Graeme; Padgett, Miles

    2007-01-01

    We report the development of a joystick controlled gripper for the real-time manipulation of micron-sized objects, driven using holographic optical tweezers (HOTs). The gripper consists of an arrangement of four silica beads, located in optical traps, which can be positioned and scaled in order to trap an object indirectly. The joystick can be used to grasp, move (lateral or axial), and change the orientation of the target object. The ability to trap objects indirectly allows us to demonstrate the manipulation of a strongly scattering micron-sized metallic particle.

  8. Potential of ultrafiltration for organic matter removal in the polymer industry effluent based on particle size distribution analysis.

    PubMed

    Doğruel, Serdar; Çokgör, Emine Ubay; Ince, Orhan; Sözen, Seval; Orhon, Derin

    2013-01-01

    The purpose of the study was the experimental evaluation of ultrafiltration as a potential innovative technology for the removal of organic matter of around 15,000 mg chemical oxygen demand (COD) per liter in the polymer industry wastewater. Particle size distribution (PSD) analysis served as the major experimental instrument along with conventional chemical settling. Biodegradation characteristics of the remaining COD after ultrafiltration were determined by model interpretation of the corresponding oxygen uptake rate (OUR) profile. The study first involved a detailed characterization of the polymer wastewater including PSD analysis of the COD content. Chemical treatability was investigated using lime alone and with ferric chloride as coagulants followed with a PSD assessment of the chemically settled effluent. Modeling of the OUR profile generated by the ultrafiltration effluent defined related biodegradation kinetics and provided information on the overall COD removal potential. PSD analysis indicated that more than 70 % of the total COD accumulated in the 220- to 450-nm size range. It indicated that ultrafiltration was potentially capable of removing more than 90 % of the COD with an effluent lower than 1,500 mg COD/L. Chemical settling with 750 mg/L of FeCl(3) dosing at a pH of 7.0 provided a similar performance. The ultrafiltration effluent included mainly hydrolysable COD and proved to be biodegradable, with the process kinetics compatible with domestic sewage. PSD evaluation proved to be a valuable scientific instrument for underlining the merit of ultrafiltration as the appropriate innovative technology for polymer wastewater, removing the major portion of the COD in a way that is suitable for recovery and reuse and producing a totally biodegradable effluent.

  9. Effects of Aftermarket Control Technologies on Gas and Particle Phase Oxidative Potential from Diesel Engine Emissions.

    PubMed

    Pavlovic, Jelica; Holder, Amara L; Yelverton, Tiffany L B

    2015-09-01

    Particulate matter (PM) originating from diesel combustion is a public health concern due to its association with adverse effects on respiratory and cardiovascular diseases and lung cancer. This study investigated emissions from three stationary diesel engines (gensets) and varying power output (230 kW, 400 kW, and 600 kW) at 50% and 90% load to determine concentrations of gaseous (GROS) and PM reactive oxygen species (PMROS). In addition, the influence of three modern emission control technologies on ROS emissions was evaluated: active and passive diesel particulate filters (A-DPF and P-DPF) and a diesel oxidation catalyst (DOC). PMROS made up 30-50% of the total ROS measured without aftermarket controls. All applied controls removed PMROS by more than 75% on average. However, the oxidative potential of PM downstream of these devices was not diminished at the same rate and particles surviving the A-PDF had an even higher oxidative potential on a per PM mass basis compared to the particles emitted by uncontrolled gensets. Further, the GROS as compared to PMROS emissions were not reduced with the same efficiency (<36%). GROS concentrations were highest with the DOC in use, indicating continued formation of GROS with this control. Correlation analyses showed that PMROS and to a lesser extent GROS have a good correlation with semivolatile organic carbon (OC1) subfraction. In addition, results suggest that chemical composition, rather than PM size, is responsible for differences in the PM oxidative potential.

  10. Controlled human exposures to ambient pollutant particles in susceptible populations

    EPA Science Inventory

    Epidemiologic studies have established an association between exposures to air pollution particles and human mortality and morbidity at concentrations of particles currently found in major metropolitan areas. The adverse effects of pollution particles are most prominent in suscep...

  11. Multi-particle assembled porous nanostructured MgO: its application in fluoride removal

    NASA Astrophysics Data System (ADS)

    Gangaiah, Vijayakumar; Siddaramanna, Ashoka; Thimanna Chandrappa, Gujjarahalli

    2014-12-01

    In this article, a simple and economical route based on ethylene glycol mediated process was developed to synthesize one-dimensional (1D) multiparticle assembled nanostructured MgO using magnesium acetate and urea as reactants. Porous multiparticle chain-like MgO has been synthesized by the calcination of a solvothermally derived single nanostructured precursor. The prepared products were characterized by an x-ray diffraction (XRD) pattern, thermogravimetry, scanning/transmission electron microscopy (SEM/TEM) and N2 adsorption (BET). As a proof of concept, the porous multiparticle chain-like MgO has been applied in a water treatment for isolated and rural communities, and it has exhibited an excellent adsorption capability to remove fluoride in waste water. In addition, this method could be generalized to prepare other 1D nanostructures with great potential for various attractive applications.

  12. Thermal control system. [removing waste heat from industrial process spacecraft

    NASA Technical Reports Server (NTRS)

    Hewitt, D. R. (Inventor)

    1983-01-01

    The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

  13. Transit Scratchitti Removal and Glass Resurfacing by Controlled Fire Polishing

    NASA Astrophysics Data System (ADS)

    Jun, Seongchan; Hong, Shane Y.

    Scratchitti vandalism, a new type of graffiti vandalism, in public transits systems and city neighborhood is a serious problem. To solve this problem, an innovative approach was developed-controlled fire polishing, which incorporates a technique of localized softening and surface tension. Intensive heat is positioned near to the scratch marks on the glass panel. The heat melts a thin layer of glass into liquid, changing the glass’s viscosity to a formable state. The glass is melted to a level close to the depth of the scratch, and allowed to cool down naturally. During the cooling process, the surface tension of the melted glass will even out the scratching indent. After cooling, the glass will be as even and smooth as it was originally. The process will enable the reuse of the damaged window/door and eliminate the otherwise waste by replacement new glass.

  14. Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

    PubMed

    Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

    2010-10-15

    Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories.

  15. Method for non-contact particle manipulation and control of particle spacing along an axis

    DOEpatents

    Goddard, Gregory Russ; Kaduchak, Gregory; Jett, James Hubert; Graves, Steven Wayde

    2012-09-11

    Method and system for uniformly spacing particles in a flowing system comprising suspending particles in an elongated fluid filled cavity; exposing said cavity to an axial acoustic standing wave field, wherein said axial acoustic standing wave field drives said particles to nodal and anti-nodal positions along the center axis of said cavity to result in uniformly spaced particles; and focusing said particles to the center axis of said cavity.

  16. Method for non-contact particle manipulation and control of particle spacing along an axis

    DOEpatents

    Goddard, Gregory R; Kaduchak, Gregory; Jett, James H; Graves, Steven W

    2015-01-13

    Method and system for uniformly spacing particles in a flowing system comprising suspending particles in an elongated fluid filled cavity; exposing said cavity to an axial acoustic standing wave field, wherein said axial acoustic standing wave field drives said particles to nodal and anti-nodal positions along the center axis of said cavity to result in uniformly spaced particles; and focusing said particles to the center axis of said cavity.

  17. A novel control strategy for efficient biological phosphorus removal with carbon-limited wastewaters.

    PubMed

    Guerrero, Javier; Guisasola, Albert; Baeza, Juan A

    2014-01-01

    This work shows the development and the in silico evaluation of a novel control strategy aiming at successful biological phosphorus removal in a wastewater treatment plant operating in an A(2)/O configuration with carbon-limited influent. The principle of this novel approach is that the phosphorus in the effluent can be controlled with the nitrate setpoint in the anoxic reactor as manipulated variable. The theoretical background behind this control strategy is that reducing nitrate entrance to the anoxic reactor would result in more organic matter available for biological phosphorus removal. Thus, phosphorus removal would be enhanced at the expense of increasing nitrate in the effluent (but always below legal limits). The work shows the control development, tuning and performance in comparison to open-loop conditions and to two other conventional control strategies for phosphorus removal based on organic matter and metal addition. It is shown that the novel proposed strategy achieves positive nutrient removal results with similar operational costs to the other control strategies and open-loop operation.

  18. Use of hybrid composite particles prepared using alkoxysilane-functionalized amphiphilic polymer precursors for simultaneous removal of various pollutants from water.

    PubMed

    Cho, Seulki; Kim, Nahae; Lee, Soonjae; Lee, Hoseok; Lee, Sang-Hyup; Kim, Juyoung; Choi, Jae-Woo

    2016-08-01

    In this study, we present new inorganic-organic hybrid particles and their possible application as an adsorbent for simultaneous removal of hydrophobic and hydrophilic pollutants from water. These hybrid particles were prepared using tailor-made alkoxysilane-functionalized amphiphilic polymer precursors (M-APAS), which have amphiphilic polymers and reactive alkoxysilane groups attached to the same backbone. Through a single conventional sol-gel process, the polymerization of M-APAS and the chemical conjugation of M-APAS onto silica nanoparticles was simultaneous, resulting in the formation of hybrid particles (M-APAS-SiO2) comprised of hyperbranch-like amphiphilic polymers bonded onto silica nanoparticles with a relatively high grafting efficiency. A test for the adsorption of water-soluble dye (organe-16) and water insoluble dye (solvent blue-35) onto the hybrid particles was performed to evaluate the possibility of adsorbing hydrophilic and hydrophobic compound within the same particle. The hybrid particle was also evaluated as an adsorbent for the removal of contaminated water containing various pollutants by wastewater treatment test. The hybrid particle could remove phenolic compounds from wastewater and the azo dye reactive orange-16 from aqueous solutions, and it was easily separated from the treated wastewater because of the different densities involved. These results demonstrate that the hybrid particles are a promising sorbent for hydrophilic and/or hydrophobic pollutants in water.

  19. Effect of UV radiations to control particle size of Mn-Zn spinel ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Ameen Ramiza, F.; Ajmal, S. K.; Khan, M. B.; Nasim, A.; Jamil, Y.; Kashif, K.; Amira, S.

    2016-08-01

    MnxZn1-xFe2O4 (0.0 < x < 1.0) ferrite nano particles were synthesized for concentration varying from 0.27 to 0.87 to obtain chemically homogenous powder for obtaining fine particle size by co precipitation technique. Keeping in view the interest of scientists for particle size, the present work focus on the impact of UV radiation to control the particle size of prepared fine magnetic particles. The particles were digested for ninety minutes at a temperature of 90oC. The samples were divided into four equal quantities and were subjected to different doses of UV radiation. The chemically produced samples of Mn-Zn ferrite nano particles were analyzed by XRD which confirmed cubic spinel structure of the material. The average crystallite size (t), lattice parameter (a) and other structural parameters of UV-irradiated MnxZni-xFe2O4 spinel ferrite were calculated from XRD data. The spinel peak of the irradiated sample when compared with the control sample, shifted from 35.38 to 35.15. In few samples, additional peaks supporting the ferrite structure were also observed. The variation in the particle sizes observed for various doses of UV irradiation were in the range of 17.6 to 6.2 nm, whereas the particle size of the control was 8.82nm. The experiment was repeated for different concentrations, at the same digestion temperature and time revealed the similar results indicating that UV radiations can have a remarkable effect to control the phase and size of nano size fine magnetic ferrite particles. The present work successfully document the impact of UV to control the particle size.

  20. Use of manganese oxide and activated carbon fibers for removing a particle, volatile organic compound or ozone from a gas

    SciTech Connect

    Sidheswaran, Meera A.; Destaillats, Hugo; Fisk, William J.

    2016-08-30

    The present invention provides for a device for reducing a volatile organic compound (VOC) content of a gas comprising a manganese oxide (MnO.sub.x) catalyst. The manganese oxide (MnO.sub.x) catalyst is capable of catalyzing formaldehyde at room temperature, with complete conversion, to CO.sub.2 and water vapor. The manganese oxide (MnO.sub.x) catalyst itself is not consumed by the reaction of formaldehyde into CO.sub.2 and water vapor. The present invention also provides for a device for reducing or removing a particle, a VOC and/or ozone from a gas comprising an activated carbon filter (ACF) on a media that is capable of being periodically regenerated.

  1. Biochar Supported Nanoscale Iron Particles for the Efficient Removal of Methyl Orange Dye in Aqueous Solutions

    PubMed Central

    Zhao, Shichen; Yan, Jingchun; Qian, Linbo; Chen, Mengfang

    2015-01-01

    The presence of organic contaminants in industrial effluents is an environmental concern of increasing global importance. One innovative technology for treating contaminated industrial effluents is nanoscale zero-valent iron supported on biochar (nZVI/BC). Based on Transmission Electron Microscopy, X-Ray Diffraction, and Brunauer-Emmett-Teller characterizations, the nZVI was well dispersed on the biochar and aggregation was dramatically reduced. Methyl orange (MO) served as the representative organic contaminant for verifying the effectiveness of the composite. Using decolorization efficiency as an indicator of treatment effectiveness, increasing doses of nZVI/BC yielded progressively better results with 98.51% of MO decolorized by 0.6 g/L of composite at an nZVI/BC mass ratio of 1:5. The superior decolorization efficiency of the nZVI/BC was attributed to the increase in the dispersion and reactivity of nZVI while biochar increasing the contact area with contaminant and the adsorption of composites. Additionally, the buffering function of acid-washed biochar could be in favor of maintaining the reactivity of nZVI. Furthermore, the aging nZVI/BC for 30 day was able to maintain the removal efficiency indicating that the oxidation of nZVI may be delayed in the presence of biochar. Therefore, the composite of nZVI/BC could represent an effective functional material for treating wastewater containing organic dyes in the future. PMID:26204523

  2. Aspects of droplet and particle size control in miniemulsions

    NASA Astrophysics Data System (ADS)

    Saygi-Arslan, Oznur

    Miniemulsion polymerization has become increasingly popular among researchers since it can provide significant advantages over conventional emulsion polymerization in certain cases, such as production of high-solids, low-viscosity latexes with better stability and polymerization of highly water-insoluble monomers. Miniemulsions are relatively stable oil (e.g., monomer) droplets, which can range in size from 50 to 500 nm, and are normally dispersed in an aqueous phase with the aid of a surfactant and a costabilizer. These droplets are the primary locus of the initiation of the polymerization reaction. Since particle formation takes place in the monomer droplets, theoretically, in miniemulsion systems the final particle size can be controlled by the initial droplet size. The miniemulsion preparation process typically generates broad droplet size distributions and there is no complete treatment in the literature regarding the control of the mean droplet size or size distribution. This research aims to control the miniemulsion droplet size and its distribution. In situ emulsification, where the surfactant is synthesized spontaneously at the oil/water interface, has been put forth as a simpler method for the preparation of miniemulsions-like systems. Using the in situ method of preparation, emulsion stability and droplet and particle sizes were monitored and compared with conventional emulsions and miniemulsions. Styrene emulsions prepared by the in situ method do not demonstrate the stability of a comparable miniemulsion. Upon polymerization, the final particle size generated from the in situ emulsion did not differ significantly from the comparable conventional emulsion polymerization; the reaction mechanism for in situ emulsions is more like conventional emulsion polymerization rather than miniemulsion polymerization. Similar results were found when the in situ method was applied to controlled free radical polymerizations (CFRP), which have been advanced as a

  3. Extinction and backscatter measurements of Antarctic PSC's, 1987: Implications for particle and vapor removal

    NASA Technical Reports Server (NTRS)

    Poole, L. R.; Mccormick, M. Patrick; Browell, Edward V.; Trepte, C. R.; Fahey, D. W.; Kelly, K. K.; Ferry, G. V.; Pueschel, R. F.; Jones, R. L.

    1988-01-01

    The temperature dependence is examined of optical properties measured in the Antarctic during 1987 at the 70 mb level (near 18 km), a level chosen to correlate the results with in situ measurements made from the NASA-Ames ER-2 aircraft during the 1987 Airborne Antarctic Ozone Experiment (AAOE). The data set consists of extinction measurements by Sam 2 inside the Antarctic polar vortex from May to October 1987; and backscatter measurements by the UV-DIAL (Ultraviolet Differential Absorption Lidar) system aboard the Ames DC-8 aircraft during selected AAOE flights. Observed trends are compared with results from a revised version of Pole and McCormick's model to classify the PSC observations by Type (1 or 2) and infer the temporal behavior of the ambient aerosol and ambient vapor mixing ratios. The sample figures show monthly ensembles of the 70-mb Sam 2 extinction ratio (the ratio of aerosol or PSC extinction to molecule extinction) as a function of NMC temperature at the beginning (June) and (October) of the 1987 Antarctic winter. Both ensembles show two rather distinct clusters of points: one oriented in the near vertical direction which depicts the change with temperature of the ambient aerosol extinction ratio; and a second cluster oriented in the near horizontal direction whose position on the vertical scale marks a change in particle phase (i.e., PSC formation) and whose length (the extinction enhancement related to that of the ambient aerosol) is an indicator of PSC type.

  4. Generation of nano-sized core-shell particles using a coaxial tri-capillary electrospray-template removal method.

    PubMed

    Cao, Lihua; Luo, Jun; Tu, Kehua; Wang, Li-Qun; Jiang, Hongliang

    2014-03-01

    This study proposed a new strategy based on a coaxial tri-capillary electrospray-template removal process for producing nanosized polylactide-b-polyethylene glycol (PLA-PEG) particles with a core-shell structure. Microparticles with core-shell-corona structures were first fabricated by coaxial tri-capillary electrospray, and core-shell nanoparticles less than 200 nm in size were subsequently obtained by removing the PEG template from the core-shell-corona microparticles. The nanoparticle size could be modulated by adjusting the flow rate of corona fluid, and nanoparticles with an average diameter of 106±5 nm were obtained. The nanoparticles displayed excellent dispersion stability in aqueous media and very low cytotoxicity. Paclitaxel was used as a model drug to be incorporated into the core section of the nanoparticles. A drug loading content in the nanoparticles as high as 50.7±1.5 wt% with an encapsulation efficiency of greater than 70% could be achieved by simply increasing the feed rate of the drug solution. Paclitaxel exhibited sustained release from the nanoparticles for more than 40 days. The location of the paclitaxel in the nanoparticles, i.e., in the core or shell layer, did not have a significant effect on its release.

  5. In-situ removal and characterisation of uranium-containing particles from sediments surrounding the Fukushima Daiichi Nuclear Power Plant

    NASA Astrophysics Data System (ADS)

    Martin, P. G.; Griffiths, I.; Jones, C. P.; Stitt, C. A.; Davies-Milner, M.; Mosselmans, J. F. W.; Yamashiki, Y.; Richards, D. A.; Scott, T. B.

    2016-03-01

    Traditional methods to locate and subsequently study radioactive fallout particles have focused heavily on autoradiography coupled with in-situ analytical techniques. Presented here is the application of a Variable Pressure Scanning Electron Microscope with both backscattered electron and energy dispersive spectroscopy detectors, along with a micromanipulator setup and electron-hardening adhesive to isolate and remove individual particles before synchrotron radiation analysis. This system allows for a greater range of new and existing analytical techniques, at increased detail and speed, to be applied to the material. Using this method, it was possible to erform detailed energy dispersive spectroscopy and synchrotron radiation characterisation of material likely ejected from the Fukushima Daiichi Nuclear Power Plant found within a sediment sample collected from the edge of the 30 km exclusion zone. Particulate material sub-micron in maximum dimension examined during this work via energy dispersive spectroscopy was observed to contain uranium at levels between 19.68 and 28.35 weight percent, with the application of synchrotron radiation spectroscopy confirming its presence as a major constituent. With great effort and cost being devoted to the remediation of significant areas of eastern Japan affected by the incident, it is crucial to gain the greatest possible understanding of the nature of this contamination in order to inform the most appropriate clean-up response.

  6. Distinguishing metal bioconcentration from particulate matter in moss tissue: testing methods of removing particles attached to the moss surface.

    PubMed

    Spagnuolo, V; Giordano, S; Pérez-Llamazares, A; Ares, A; Carballeira, A; Fernández, J A; Aboal, J R

    2013-10-01

    Accurate differentiation of the proportion of bioconcentrated metals (i.e. incorporated into cells) and the proportion that is not bioconcentrated (i.e. adsorbed at the surface) would lead to a better understanding of the uptake processes and would represent an advance in the use of mosses as biomonitors. Traditionally the methods used to remove contaminants that are not bioconcentrated were to wash the plant material with water or to apply the sequential elution technique, but nowadays both options are considered inaccurate for these purposes. The remaining possibilities are to clean the moss samples with a nitrogen jet or by power ultrasound. Samples of terrestrial moss Pseudoscleropodium purum (Hewd.) Fleisch. were collected from five sampling stations. Different nitrogen jet cleaning procedures and ultrasound cleaning procedures were applied to the mosses. To determine whether any of the treatments altered the membrane integrity of the moss samples, the concentrations of K were determined. The shoots were observed under a scanning electron microscope, and the size and number of particles were determined. Nitrogen jet cleaning was determined to be unacceptable because it damaged the phyllids and/or altered the membrane permeability and did not eliminate the particles from the moss surface. Moreover, ultrasound cleaning treatment should also discarded because of the loss of extracellular metals that are transferred to the water in which the moss is cleaned.

  7. Schedules of Controlled Substances: Removal of [123I]Ioflupane From Schedule II of the Controlled Substances Act. Final rule.

    PubMed

    2015-09-11

    With the issuance of this final rule, the Administrator of the Drug Enforcement Administration removes [123I]ioflupane from the schedules of the Controlled Substances Act. This action is pursuant to the Controlled Substances Act which requires that such actions be made on the record after an opportunity for a hearing through formal rulemaking. Prior to the effective date of this rule, [123I]ioflupane was, by definition, a schedule II controlled substance because it is derived from cocaine via ecgonine, both of which are schedule II controlled substances. This action removes the regulatory controls and administrative, civil, and criminal sanctions applicable to controlled substances, including those specific to schedule II controlled substances, on persons who handle (manufacture, distribute, reverse distribute, dispense, conduct research, import, export, or conduct chemical analysis) or propose to handle [123I]ioflupane.

  8. Risk Factors for Scleral Buckle Removal: A Matched, Case-Control Study

    PubMed Central

    Covert, Douglas J.; Wirostko, William J.; Han, Dennis P.; Lindgren, Kevin E.; Hammersley, Jill A.; Connor, Thomas B.; Kim, Judy E.

    2008-01-01

    Purpose To identify preoperative, perioperative, and postoperative risk factors for scleral buckle (SB) removal. Methods A retrospective, consecutive, matched, case-control study. Cases included all patients undergoing SB removal between 1988 and 2007 at a single academic center. Case patients were matched against 4 randomly selected control patients who underwent SB implantation during the same year as the case patients. Odds ratios (ORs) were calculated for each factor investigated. Results Forty cases of SB removal and 148 matched control cases were identified. Three cases of SB removal were omitted from analysis because of incomplete records. Factors associated with SB removal for any reason, according to univariate analysis, included concurrent globe-penetrating injury at the time of SB placement (OR, 24; 95% confidence interval [CI], 2.9–200), concurrent pars plana vitrectomy (PPV) (OR, 17.3; CI, 4.9–61), diabetes mellitus (DM) (OR, 7.3; CI, 1.8–30), prior long-term topical ocular therapy (OR, 4.3; CI, 1.7–11), and subsequent ocular procedures (OR, 3.4; CI, 1.5–7.5). Factors independently associated with SB removal according to multivariate analysis included concurrent globe-penetrating injury (OR, 27.3; CI, 1.7–426), concurrent PPV (OR, 11.3; CI, 2.9–45), DM (OR, 8.9; CI, 1.3–58), and subsequent ocular procedures (OR, 3.9; CI, 1.4–11). Factors that did not alter SB removal risk included patient age; sex; and type, size, or location of buckling elements used. Conclusions Awareness of these risk factors may be valuable for the surgical planning of retinal detachment repair in patients at higher risk for subsequent SB removal and for risk stratification subsequent to SB implantation. PMID:19277232

  9. [Characteristics of nitrogen and phosphorus removal and control of membrane fouling in MBR and SMBR].

    PubMed

    Guo, Xiao-Ma; Zhao, Yan; Wang, Kai-Yan; Zhao Yang-Guo

    2015-03-01

    To improve the efficiency and running stability of wastewater advanced treatment, a sequencing membrane bioreactor (SMBR) and a traditional membrane bioreactor (MBR) were used to investigate the characteristics of nitrogen and phosphorus removal, and the effect of anoxic time on treatment systems and membrane fouling. Simultaneously, molecular biology techniques were applied to analyze the composition of microbial community and the structure of suspended sludge. The results showed that SMBR had higher efficiency in removing TN than MBR, which indicated that intermittent aeration could enhance the ability of nitrogen removal. SMBR and MBR had a similar removal efficiency of NH4(+)-N, TP, COD, and turbidity with the removal rates of 94%, 78%, 80%, and 97%, respectively. Extension of SMBR anoxic time had no effect on COD, NH4(+) -N removal but decreased TN and TP removal rate, dropping from 61% and 74% to 46% and 52%, respectively. Intermittent aeration and powder activated carbon (PAC) could both mitigate membrane fouling. The analysis on microbial community indicated that there was no difference in the composition and structure of microbial community between SMBR and MBR. Nitrospira and Dechloromonas were both highly abundant functional groups, which provided the basis for highly efficient control of bioreactors.

  10. Assessment of disease lesion removal as a method to control chronic Montipora white syndrome.

    PubMed

    Beurmann, Silvia; Runyon, Christina M; Videau, Patrick; Callahan, Sean M; Aeby, Greta S

    2017-03-06

    Coral colonies in Kāne'ohe Bay, Hawai'i (USA), are afflicted with the tissue loss disease chronic Montipora white syndrome (cMWS). Here we show that removal of chronic disease lesions is a potential method to slow the progression of cMWS in M. capitata. Over the 24 wk observation period, treatment colonies lost almost half the amount of tissue that was lost by control colonies. The percentage of tissue loss at each sampling interval (mean ± SEM; treatment: 1.17 ± 0.47%, control: 2.25 ± 0.63%) and the rate of tissue loss per day (treatment: 0.13 ± 0.04%, control: 0.27 ± 0.08%) were both significantly lower on treated colonies than control colonies. While lesion removal stopped tissue loss at the initial infection site, which allowed colony healing, it did not prevent re-infection; in all but one of the treated colonies, new cMWS lesions appeared in other areas of the colony but not around the treatment margins. Additionally, the rate of new infections was similar between treatment and control colonies, indicating that physical injury from lesion removal did not appear to increase cMWS susceptibility. These results indicate that lesion removal reduced morbidity in M. capitata exhibiting cMWS but did not stop the disease.

  11. Validation and Application of the Mass Balance Model To Determine the Effectiveness of Portable Air Purifiers in Removing Ultrafine and Submicrometer Particles in an Apartment.

    PubMed

    Lee, Wan-Chen; Catalano, Paul J; Yoo, Jun Young; Park, Chan Jung; Koutrakis, Petros

    2015-08-18

    We validated the use of the mass balance model to determine the effectiveness of portable air purifiers in removing ultrafine (<0.10 μm) and submicrometer particles (0.10-0.53 μm) in an apartment. We evaluated two identical portable air purifiers, equipped with high efficiency particulate air filters, for their performance under three different air flow settings and three target air exchange rates: 0.60, 0.90, and 1.20 h(-1). We subsequently used a mixed effects model to estimate the slope between the measured and modeled effectiveness by particle size. Our study showed that effectiveness was highly particle size-dependent. For example, at the lowest target air exchange rate, it ranged from 0.33 to 0.56, 0.51 to 0.75, and 0.60 to 0.81 for the three air purifier flow settings, respectively. Our findings suggested that filtration was the dominant removal mechanism for submicrometer particles, whereas deposition could play a more important role in ultrafine particle removal. We found reasonable agreement between measured and modeled effectiveness with size-resolved slopes ranging from 1.11 ± 0.06 to 1.25 ± 0.07 (mean ± SE), except for particles <35 nm. Our study design can be applied to investigate the performances of other portable air purifiers as well as the influences of various parameters on effectiveness in different residential settings.

  12. Tuning selectivity in catalysis by controlling particle shape

    NASA Astrophysics Data System (ADS)

    Lee, Ilkeun; Delbecq, Françoise; Morales, Ricardo; Albiter, Manuel A.; Zaera, Francisco

    2009-02-01

    A catalytic process for the selective formation of cis olefins would help minimize the production of unhealthy trans fats during the partial hydrogenation of edible oils. Here we report on the design of such a process on the basis of studies with model systems. Temperature programmed desorption data on single crystals showed that the isomerization of trans olefins to their cis counterparts is promoted by (111) facets of platinum, and that such selectivity is reversed on more open surfaces. Quantum mechanics calculations suggested that the extra stability of cis olefins seen on hydrogen-saturated Pt(111) surfaces may be due to a lesser degree of surface reconstruction, a factor found to be significant in the adsorption on close-packed platinum surfaces. Kinetic data using catalysts made out of dispersed tetrahedral Pt nanoparticles corroborated the selective promotion of the trans-to-cis isomerization on the (111) facets of the metal. Our work provides an example for how catalytic selectivity may be controlled by controlling the shape of the catalytic particles.

  13. Growth and control of microscale to nanoscale carbon nitride particles

    SciTech Connect

    Li, H. Y.; Shi, Y. C.; Feng, P. X.

    2006-10-02

    Microscale to nanoscale carbon nitride (China) particles are prepared using plasma sputtering deposition techniques. The preferred orientation of nanoscale CN particle distributions is obtained. Particles are examined using scanning electron microscopy (SEM) and Raman scattering spectroscopy. SEM micrographs show that the CN particles are spherical with nearly the same diameters of 2.5 {mu}m prepared without setting bias voltage. The distribution of these particles is random. Setting bias voltage up to 5 kV, plasma sputtering deposition yields several dispersed ring patterns of particle distributions where many small groups of nanoscale particles are observed. Each group of these particles is in a sunflower type of distribution, in which the biggest (85 nm) particle at the center is surrounded by many small sizes (30 nm) of CN particles. Disk type of the particles with a diameter of 10 {mu}m is also observed at different deposition conditions. Typical carbon bands and CN band in the Raman spectra of the samples are identified. The intensity of the bands obviously varies at the different deposition conditions.

  14. Removal of Particles and Acid Gases (SO2 or HCl) with a Ceramic Filter by Addition of Dry Sorbents

    SciTech Connect

    Hemmer, G.; Kasper, G.; Wang, J.; Schaub, G.

    2002-09-20

    The present investigation intends to add to the fundamental process design know-how for dry flue gas cleaning, especially with respect to process flexibility, in cases where variations in the type of fuel and thus in concentration of contaminants in the flue gas require optimization of operating conditions. In particular, temperature effects of the physical and chemical processes occurring simultaneously in the gas-particle dispersion and in the filter cake/filter medium are investigated in order to improve the predictive capabilities for identifying optimum operating conditions. Sodium bicarbonate (NaHCO{sub 3}) and calcium hydroxide (Ca(OH){sub 2}) are known as efficient sorbents for neutralizing acid flue gas components such as HCl, HF, and SO{sub 2}. According to their physical properties (e.g. porosity, pore size) and chemical behavior (e.g. thermal decomposition, reactivity for gas-solid reactions), optimum conditions for their application vary widely. The results presented concentrate on the development of quantitative data for filtration stability and overall removal efficiency as affected by operating temperature. Experiments were performed in a small pilot unit with a ceramic filter disk of the type Dia-Schumalith 10-20 (Fig. 1, described in more detail in Hemmer 2002 and Hemmer et al. 1999), using model flue gases containing SO{sub 2} and HCl, flyash from wood bark combustion, and NaHCO{sub 3} as well as Ca(OH){sub 2} as sorbent material (particle size d{sub 50}/d{sub 84} : 35/192 {micro}m, and 3.5/16, respectively). The pilot unit consists of an entrained flow reactor (gas duct) representing the raw gas volume of a filter house and the filter disk with a filter cake, operating continuously, simulating filter cake build-up and cleaning of the filter medium by jet pulse. Temperatures varied from 200 to 600 C, sorbent stoichiometric ratios from zero to 2, inlet concentrations were on the order of 500 to 700 mg/m{sup 3}, water vapor contents ranged from

  15. IET control building (TAN620). equipment removed. Lube oil and waste ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    IET control building (TAN-620). equipment removed. Lube oil and waste piping at upper right. Fire door on right. Rebar exposed in concrete of ceiling. INEEL negative no. HD-21-5-3 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  16. Solar Anomalous and Magnetospheric Particle Explorer attitude control electronics box design and performance

    NASA Technical Reports Server (NTRS)

    Chamberlin, K.; Clagett, C.; Correll, T.; Gruner, T.; Quinn, T.; Shiflett, L.; Schnurr, R.; Wennersten, M.; Frederick, M.; Fox, S. M.

    1993-01-01

    The attitude Control Electronics (ACE) Box is the center of the Attitude Control Subsystem (ACS) for the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite. This unit is the single point interface for all of the Attitude Control Subsystem (ACS) related sensors and actuators. Commands and telemetry between the SAMPEX flight computer and the ACE Box are routed via a MIL-STD-1773 bus interface, through the use of an 80C85 processor. The ACE Box consists of the flowing electronic elements: power supply, momentum wheel driver, electromagnet driver, coarse sun sensor interface, digital sun sensor interface, magnetometer interface, and satellite computer interface. In addition, the ACE Box also contains an independent Safehold electronics package capable of keeping the satellite pitch axis pointing towards the sun. The ACE Box has dimensions of 24 x 31 x 8 cm, a mass of 4.3 kg, and an average power consumption of 10.5 W. This set of electronics was completely designed, developed, integrated, and tested by personnel at NASA GSFC. SAMPEX was launched on July 3, 1992, and the initial attitude acquisition was successfully accomplished via the analog Safehold electronics in the ACE Box. This acquisition scenario removed the excess body rates via magnetic control and precessed the satellite pitch axis to within 10 deg of the sun line. The performance of the SAMPEX ACS in general and the ACE Box in particular has been quite satisfactory.

  17. The effect of particle size distribution on the design of urban stormwater control measures

    USGS Publications Warehouse

    Selbig, William R.; Fienen, Michael N.; Horwatich, Judy A.; Bannerman, Roger T.

    2016-01-01

    An urban pollutant loading model was used to demonstrate how incorrect assumptions on the particle size distribution (PSD) in urban runoff can alter the design characteristics of stormwater control measures (SCMs) used to remove solids in stormwater. Field-measured PSD, although highly variable, is generally coarser than the widely-accepted PSD characterized by the Nationwide Urban Runoff Program (NURP). PSDs can be predicted based on environmental surrogate data. There were no appreciable differences in predicted PSD when grouped by season. Model simulations of a wet detention pond and catch basin showed a much smaller surface area is needed to achieve the same level of solids removal using the median value of field-measured PSD as compared to NURP PSD. Therefore, SCMs that used the NURP PSD in the design process could be unnecessarily oversized. The median of measured PSDs, although more site-specific than NURP PSDs, could still misrepresent the efficiency of an SCM because it may not adequately capture the variability of individual runoff events. Future pollutant loading models may account for this variability through regression with environmental surrogates, but until then, without proper site characterization, the adoption of a single PSD to represent all runoff conditions may result in SCMs that are under- or over-sized, rendering them ineffective or unnecessarily costly.

  18. Control of adhesion force between ceria particles and polishing pad in shallow trench isolation chemical mechanical planarization.

    PubMed

    Seo, Jihoon; Moon, Jinok; Bae, Jae-Young; Yoon, Kwang Seob; Sigmund, Wolfgang; Paik, Ungyu

    2014-06-01

    The adhesion force between ceria and polyurethane (PU) pad was controlled to remove the step height from cell region to peripheral region during Shallow Trench Isolation Chemical Mechanical Planarization (STI-CMP) for NAND flash. Picolinic acid was found to be adsorbed on ceria particles at pH 4.5 following a Langmuir isotherm with the maximum adsorbed amount of 0.36 mg/m2. The ceria suspension with full surface coverage of picolinic acid showed a threefold increase in the number of adhered ceria particles on the PU pad over non-coated ceria particles. It was shown that the coverage percent of picolinic acid on ceria corresponds well with the amount percent of adsorbed ceria on PU pad. The change in adsorbed particles was directly reflected in the CMP polishing process where significant improvements were achieved. Particularly, convex areas on the chip experienced higher friction force from the attached abrasives on the PU pad than concave areas. As a result, the convex areas have increased removal rate of step height compared to the ceria suspension without picolinic acid. The changing profiles of convex areas are reported during the step height reduction as a function of polishing time.

  19. Removal of oxygen demand and nitrogen using different particle-sizes of anthracite coated with nine kinds of LDHs for wastewater treatment

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangling; Guo, Lu; Wang, Yafen; Ruan, Congying

    2015-10-01

    This paper reports the application of anthracite particles of different sizes and coated with nine kinds of layered double hydroxides (LDHs) varying in MII-MIII cations, as alternative substrates in the simulated vertical-flow constructed wetland columns. Effects of LDHs-coating and particle size of modified anthracites were examined to evaluate their abilities in removing oxygen demand and nitrogen from sewage wastewater. Results showed that LDHs modification effectively enhanced the removal of nitrogen and organics. The removal efficiencies of total nitrogen (TN) , ammonia and chemical oxygen demand (COD) were best improved by 28.5%, 11.9% and 4.1% for the medium particle size (1-3 mm), followed by 9.2%, 5.5% and 13.6% for the large size (3-5 mm), respectively. Only TN removal was improved up to 16.6% for the small particle size (0.5-1 mm). Nitrate tended to accumulate and fluctuate greatly across all the treatments, probably due to the dominancy of aerobic condition in the vertical-flow columns. Overall, MgFe-LDHs was selected as the best-modified coating for anthracite. The results suggested LDHs modification would be one of the promising strategies to provide new-types of highly efficient and lasting wetland substrates.

  20. Synthesizing aluminum particles towards controlling electrostatic discharge ignition sensitivity

    SciTech Connect

    Eric S. Collins; Jeffery P. Gesner; Michelle L. Pantoya; Michael A. Daniels

    2014-02-01

    Aluminum particles were synthesized with shell thicknesses ranging from 2.7 to 8.3 nm and a constant diameter of 95 nm. These fuel particles were combined with molybdenum trioxide particles and the electrostatic discharge (ESD) sensitivity of the mixture was measured. Results show ignition delay increased as the alumina shell thickness increased. These results correlated with electrical resistivity measurements of the mixture which increased with alumina concentration. A model was developed using COMSOL for ignition of a single Al particle. The ignition delay in the model was consistent with the experimental results suggesting that the primary ESD ignition mechanism is joule heating.

  1. Adaptive control for space debris removal with uncertain kinematics, dynamics and states

    NASA Astrophysics Data System (ADS)

    Huang, Panfeng; Zhang, Fan; Meng, Zhongjie; Liu, Zhengxiong

    2016-11-01

    As the Tethered Space Robot is considered to be a promising solution for the Active Debris Removal, a lot of problems arise in the approaching, capturing and removing phases. Particularly, kinematics and dynamics parameters of the debris are unknown, and parts of the states are unmeasurable according to the specifics of tether, which is a tough problem for the target retrieval/de-orbiting. This work proposes a full adaptive control strategy for the space debris removal via a Tethered Space Robot with unknown kinematics, dynamics and part of the states. First we derive a dynamics model for the retrieval by treating the base satellite (chaser) and the unknown space debris (target) as rigid bodies in the presence of offsets, and involving the flexibility and elasticity of tether. Then, a full adaptive controller is presented including a control law, a dynamic adaption law, and a kinematic adaption law. A modified controller is also presented according to the peculiarities of this system. Finally, simulation results are presented to illustrate the performance of two proposed controllers.

  2. Efficacy of potential chemical control compounds for removing invasive American bullfrogs (Rana catesbeiana).

    PubMed

    Witmer, Gary W; Snow, Nathan P; Moulton, Rachael S

    2015-01-01

    Invasive American bullfrogs [Rana catesbeiana (Lithobates catesbeianus)] are outcompeting and predating on native biota and contributing to reductions in biodiversity worldwide. Current methods for controlling American bullfrogs are incapable of stopping their expansion, thus more cost-effective and broadly applicable methods are needed. Although chemical control compounds have been identified as effective for removing other invasive amphibians, none have been tested for American bullfrogs. Our objective was to expand on previous research and test the efficacy of 10 potential chemical control compounds for removing invasive American bullfrogs. After a dermal spray-application of 4 ml, we found 3 compounds (i.e., chloroxylenol, rotenone with permethrin, and caffeine) at 5-10 % concentrations in water were 100 % lethal for adult American bullfrogs. Chloroxylenol and rotenone with permethrin were fast acting with time-to-death <2 h. This research presents a first-step toward incorporating chemical control as part of integrated pest management strategy for controlling invasive American bullfrogs. Follow-up studies on delivery systems and reducing non-target hazards should ensue with these compounds to confirm their effectiveness and safety for removing invasive American bullfrogs.

  3. Geosmin and 2-methylisoborneol removal using superfine powdered activated carbon: shell adsorption and branched-pore kinetic model analysis and optimal particle size.

    PubMed

    Matsui, Yoshihiko; Nakao, Soichi; Taniguchi, Takuma; Matsushita, Taku

    2013-05-15

    2-Methylisoborneol (MIB) and geosmin are naturally occurring compounds responsible for musty-earthy taste and odor in public drinking-water supplies, a severe problem faced by many utilities throughout the world. In this study, we investigated adsorptive removal of these compounds by superfine powdered activation carbon (SPAC, particle size <1 μm) produced by novel micro-grinding of powdered activated carbon; we also discuss the optimization of carbon particle size to efficiently enhance the adsorptive removal. After grinding, the absorptive capacity remained unchanged for a 2007 carbon sample and was increased for a 2010 carbon sample; the capacity increase was quantitatively described by the shell adsorption model, in which MIB and geosmin adsorbed more in the exterior of a carbon particle than in the center. The extremely high uptake rates of MIB and geosmin by SPAC were simulated well by a combination of the branched-pore kinetic model and the shell adsorption model, in which intraparticle diffusion through macropores was followed by diffusion from macropore to micropore. Simulations suggested that D40 was on the whole the best characteristic diameter to represent a size-disperse group of adsorbent particles; D40 is the diameter through which 40% of the particles by volume pass. Therefore, D40 can be used as an index for evaluating the improvement of adsorptive removal that resulted from pulverization. The dose required for a certain percentage removal of MIB or geosmin decreased linearly with carbon particle size (D40), but the dose reduction became less effective as the activated carbon was ground down to smaller sizes around a critical value of D40. For a 60-min contact time, critical D40 was 2-2.5 μm for MIB and 0.4-0.5 μm for geosmin. The smaller critical D40 was when the shorter the carbon-water contact time was or the slower the intraparticle mass transfer rate of an adsorbate was.

  4. An assessment of lead controls for torch cutting and rivet removal on steel structures.

    PubMed

    Goldberg, M; Clark, N L; Levin, S M; Zuckerman, N; Doucette, J T

    2000-05-01

    The use of engineering and work practice controls to protect workers from lead-containing dusts and fumes generated during rehabilitation of steel structures is mandated by the Occupational Safety and Health Administration (OSHA) Lead in Construction Standard (1993). Because the implementation and assessment of controls can be problematic in the rugged and dynamic construction environment, industrial hygienists should understand the effectiveness and limitations of controls adopted. The present investigation assesses the efficacy of two controls to reduce lead exposure: paint removal prior to oxy-acetylene torch cutting of steel, and encapsulation of rivets prior to their removal. A task-based exposure assessment approach was used to evaluate these tasks at three sites. Exposures at one site without controls were compared to exposures at sites with controls. Comparison of the results via an analysis of variance (0.05 significance level) indicates that, for torch cutting, exposures at the control site were not significantly different from those at an uncontrolled site (p = 0.14). The results for rivet busting show no significant differences in exposures at the control site compared to the uncontrolled site (p = 0.08). Results are also presented from two control sites where work was done in enclosed spaces. Two main difficulties in applying the controls are explored: technical and managerial. Technical problems during torch cutting included the penetration of paint into the steel profile and the configuration of the structures. For rivet busting, working within an enclosure was an important factor. Management problems arose both from a lack of coordination among different contractors, and from a failure to provide day-to-day guidance and assessment of the control. Important components of a program to implement controls are preplanning and coordination of control implementation, frequent testing of control efficacy, and a method for timely intervention to correct

  5. A hybrid mathematical model for controlling particle size, particle size distribution, and color properties of toner particles

    NASA Astrophysics Data System (ADS)

    Ataeefard, Maryam; Shadman, Alireza; Saeb, Mohammad Reza; Mohammadi, Yousef

    2016-08-01

    A mathematical modeling approach was proposed combining the capabilities of response surface methodology (RSM) and desirability function (DF) and implemented successfully in production of printing toner particles. Toner powders were systematically synthesized through suspension copolymerization process. Applying RSM, a series of experiments were designed and toner particles were prepared and the effects of monomer ratio, colorant and surfactant content on the particle size (PS), particle size distribution (PSD), thermal and colorimetric properties (∆ E) of the resulting toner were monitored and discussed. The second-order models corresponding to each target characteristic, i.e., PS, PSD, and ∆ E of different types of toner powders, were obtained by individual optimization to express variation of each property in terms of polymerization parameters. Applying statistical calculations, the best reduced models were identified to be fed in the second step of optimization. Since toners with appropriate PS, PSD, and CP were needed, we applied multi-objective optimization based on DF approach. The results show that exact tuning of toner properties is closely possible with the aid of hybrid mathematical model developed in this work. Noticeably, desirabilities are very close to 100 %.

  6. Biofiltration for removal of BOM and residual ammonia following control of bromate formation.

    PubMed

    Wert, Eric C; Neemann, Jeffrey J; Rexing, David J; Zegers, Ronald E

    2008-01-01

    Nitrification was developed within a biological filter to simultaneously remove biodegradable organic matter (BOM) and residual ammonia added to control bromate formation during the ozonation of drinking water. Testing was performed at pilot-scale using three filters containing sand and anthracite filter media. BOM formed during ozonation (e.g., assimilable organic carbon (396-572 microg/L), formaldehyde (11-20 microg/L), and oxalate (83-145 microg/L)) was up to 70% removed through biofiltration. Dechlorinated backwash water was required to develop the nitrifying bacteria needed to convert the residual ammonia (0.1-0.5 mg/L NH(3)-N) to nitrite and then to nitrate. Chlorinated backwash water resulted in biofiltration without nitrification. Deep-bed filtration (empty-bed contact time (EBCT) = 8.3 min) did not enhance the development of nitrification when compared with shallow-bed filtration (EBCT = 3.2 min). Variable filtration rates between 4.8 and 14.6 m/h (2 and 6 gpm/sf) had minimal impact on BOM removal. However, conversion of ammonia to nitrite was reduced by 60% when increasing the filtration rate from 4.8 to 14.6 m/h. The results provide drinking water utilities practicing ozonation with a cost-effective alternative to remove the residual ammonia added for bromate control.

  7. Particle control near reticle and optics using showerhead

    DOEpatents

    Delgado, Gildardo R.; Chilese, Frank; Garcia, Rudy; Torczynski, John R.; Geller, Anthony S.; Rader, Daniel J.; Klebanoff, Leonard E.; Gallis, Michail A.

    2016-01-26

    A method and an apparatus to protect a reticle against particles and chemicals in an actinic EUV reticle inspection tool are presented. The method and apparatus utilizes a pair of porous metal diffusers in the form of showerheads to provide a continual flow of clean gas. The main showerhead bathes the reticle surface to be inspected in smoothly flowing, low pressure gas, isolating it from particles coming from surrounding volumes. The secondary showerhead faces away from the reticle and toward the EUV illumination and projection optics, supplying them with purge gas while at the same time creating a buffer zone that is kept free of any particle contamination originating from those optics.

  8. Ammonia-based intermittent aeration control optimized for efficient nitrogen removal.

    PubMed

    Regmi, Pusker; Bunce, Ryder; Miller, Mark W; Park, Hongkeun; Chandran, Kartik; Wett, Bernhard; Murthy, Sudhir; Bott, Charles B

    2015-10-01

    This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points. The unique feature of the ammonia-based aeration control was that a fixed dissolved oxygen (DO) set-point was used and the length of the aerobic and anoxic time (anoxic time ≥25% of total cycle time) were changed based on the effluent ammonia concentration. Unlike continuously aerated ammonia-based aeration control strategies, this approach offered control over the aerobic solids retention time (SRT) to deal with fluctuating ammonia loading without solely relying on changes to the total SRT. This approach allowed the system to be operated at a total SRT with a small safety factor. The benefits of operating at an aggressive SRT were reduced hydraulic retention time (HRT) for nitrogen removal. As a result of such an operation, nitrite oxidizing bacteria (NOB) out-selection was also obtained (ammonia oxidizing bacteria [AOB] maximum activity: 400 ± 79 mgN/L/d, NOB maximum activity: 257 ± 133 mgN/L/d, P < 0.001) expanding opportunities for short-cut nitrogen removal. The pilot demonstrated a total inorganic nitrogen (TIN) removal rate of 95 ± 30 mgN/L/d at an influent chemical oxygen demand: ammonia (COD/NH4 (+) -N) ratio of 10.2 ± 2.2 at 25°C within the hydraulic retention time (HRT) of 4 h and within a total SRT of 5-10 days. The TIN removal efficiency up to 91% was observed during the study, while effluent TIN was 9.6 ± 4.4 mgN/L. Therefore, this pilot-scale study demonstrates that application of the proposed on-line aeration control is capable of relatively high nitrogen removal without supplemental carbon and alkalinity addition at a low HRT.

  9. Adsorption of inorganic and organic ligands onto hydrous aluminum oxide: evaluation of surface charge and the impacts on particle and NOM removal during water treatment.

    PubMed

    Pommerenk, Peter; Schafran, Gary C

    2005-09-01

    The variable removal from solution of sulfate, orthophosphate, fluoride, five simple organic acids, and natural organic matterfromtwo sources by adsorption on aluminum hydroxide was examined to assess their potential influence on coagulation during drinking water treatment. Measurements of electrophoretic mobility were conducted with adsorption studies to provide means of evaluating the impact of the adsorption of these anions on the removal of particulate material during coagulation at water treatment facilities. The three inorganic ions exhibited widely different trends in terms of removal from solution and effect on the surface charge of the aluminum hydroxide. Phosphate was nearly completely removed from solution across a wide pH range and was observed to lower surface charge and shift the isoelectric point. Sulfate was removed to a lesser extent than phosphate, lowered the surface charge on the precipitate, but did not shiftthe isoelectric point. Fluoride was well-removed through adsorption but exhibited no influence on the charge of the hydrous aluminum oxide. The organic acids similarly displayed varying abilities to be removed through adsorption and different influences on surface charge. The results indicate the importance of the number and location of functional groups and their acid/ base properties. The ability to strongly influence surface charge illustrates the impact that adsorption of these anions can have on particle stability.

  10. 40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... device emission destruction or removal efficiency? 63.4766 Section 63.4766 Protection of Environment... Coating of Wood Building Products Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the add-on control device emission destruction or removal...

  11. Nanoscale zero-valent iron particles supported on reduced graphene oxides by using a plasma technique and their application for removal of heavy-metal ions.

    PubMed

    Li, Jie; Chen, Changlun; Zhang, Rui; Wang, Xiangke

    2015-06-01

    Nanoscale zero-valent iron particles supported on reduced graphene oxides (NZVI/rGOs) from spent graphene oxide (GO)-bound iron ions were developed by using a hydrogen/argon plasma reduction method to improve the reactivity and stability of NZVI. The NZVI/rGOs exhibited excellent water treatment performance with excellent removal capacities of 187.16 and 396.37 mg g(-1) for chromium and lead, respectively. Moreover, the NZVI/rGOs could be regenerated by plasma treatment and maintained high removal ability after four cycles. X-ray photoelectron spectroscopy analysis results implied that the removal mechanisms could be attributed to adsorption/precipitation, reduction, or both. Such multiple removal mechanisms by the NZVI/rGOs were attributed to the reduction ability of the NZVI particles and the role of dispersing and stabilizing abilities of the rGOs. The results indicated that the NZVI/rGOs prepared by a hydrogen/argon plasma reduction method might be an effective composite for heavy-metal-ion removal.

  12. Laboratory and clinical stain removal evaluations of two tartar control dentifrices.

    PubMed

    Yankell, S L; Emling, R C; Prencipe, M; Rustogi, K; Volpe, A R

    1995-01-01

    The purpose of this research was to evaluate Colgate original Tartar Control dentifrice (TC) and new Colgate Micro Cleansing Tartar Control (MCTC) dentifrice in a laboratory and clinical study for their ability to remove induced stain. In the laboratory study, polished and etched bovine enamel specimens were stained for 4 days with a coffee, tea, and mucin, Sarcina lutea tartox culture in trypticase soy broth. Sixteen specimens were then brushed for 200 strokes with a sodium carboxymethyl cellulose solution to remove loose stain, and then brushed for 300 strokes with a 1:1 toothpaste slurry. Tooth color was measured by reflectance with the CLE L*a*b* scale. The calculated stain removal, 37% for MCTC and 24% for TC, was significantly different (p<0.01) favoring the MCTC dentifrice. In the clinical study, eight-six subjects were given Peridex (0.12% chlorhexidine gluconate) mouthrinse, a low abrasive dentifrice and a soft toothbrush to use twice a day for 8 weeks. Stain was monitored on the buccal and lingual surfaces of the anterior teeth using the Lobene index. The seventy-seven subjects with sufficient total stain were stratified into two balanced groups, given a new soft toothbrush and were randomly assigned to use one of the dentifrices tested, twice a day for 8 weeks. At 4, 6 and 8 weeks in the study, the MCTC dentifrice product had consistent, significantly (p<0.05-0.001) lower total stain scores than the TC dentifrice. In the laboratory and clinical studies conducted, even though stain induction and evaluation procedures differed, the new Colgate Micro Cleansing Tartar Control dentifrice was significantly more effective at removing stain than the Colgate original Tartar Control dentifrice formula.

  13. Evaluation of mercury speciation and removal through air pollution control devices of a 190 MW boiler.

    PubMed

    Wu, Chengli; Cao, Yan; Dong, Zhongbing; Cheng, Chinmin; Li, Hanxu; Pan, Weiping

    2010-01-01

    Air pollution control devices (APCDs) are installed at coal-fired power plants for air pollutant regulation. Selective catalytic reduction (SCR) and wet flue gas desulfurization (FGD) systems have the co-benefits of air pollutant and mercury removal. Configuration and operational conditions of APCDs and mercury speciation affect mercury removal efficiently at coal-fired utilities. The Ontario Hydro Method (OHM) recommended by the U.S. Environmental Protection Agency (EPA) was used to determine mercury speciation simultaneously at five sampling locations through SCR-ESP-FGD at a 190 MW unit. Chlorine in coal had been suggested as a factor affecting the mercury speciation in flue gas; and low-chlorine coal was purported to produce less oxidized mercury (Hg2+) and more elemental mercury (Hg0) at the SCR inlet compared to higher chlorine coal. SCR could oxidize elemental mercury into oxidized mercury when SCR was in service, and oxidation efficiency reached 71.0%. Therefore, oxidized mercury removal efficiency was enhanced through a wet FGD system. In the non-ozone season, about 89.5%-96.8% of oxidized mercury was controlled, but only 54.9%-68.8% of the total mercury was captured through wet FGD. Oxidized mercury removal efficiency was 95.9%-98.0%, and there was a big difference in the total mercury removal efficiencies from 78.0% to 90.2% in the ozone season. Mercury mass balance was evaluated to validate reliability of OHM testing data, and the ratio of mercury input in the coal to mercury output at the stack was from 0.84 to 1.08.

  14. Improvement of COD removal by controlling the substrate degradability during the anaerobic digestion of recalcitrant wastewater.

    PubMed

    Kawai, Minako; Nagao, Norio; Kawasaki, Nobuyuki; Imai, Akio; Toda, Tatsuki

    2016-10-01

    The recalcitrant landfill leachate was anaerobically digested at various mixing ratios with labile synthetic wastewater to evaluate the degradation properties of recalcitrant wastewater. The proportion of leachate to the digestion system was increased in three equal steps, starting from 0% to 100%, and later decreased back to 0% with the same steps. The chemical oxygen demand (COD) for organic carbon and other components were calculated by analyzing the COD and dissolved organic carbon (DOC), and the removal efficiencies of COD carbon and COD others were evaluated separately. The degradation properties of COD carbon and COD others shifted owing to changing of substrate degradability, and the removal efficiencies of COD carbon and COD others were improved after supplying 100% recalcitrant wastewater. The UV absorptive property and total organic carbon (TOC) of each molecular size using high performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with UVA and TOC detectors were also investigated, and the degradability of different molecular sizes was determined. Although the SEC system detected extracellular polymeric substances (EPS), which are produced by microbes in stressful environments, during early stages of the experiment, EPS were not detected after feeding 100% recalcitrant wastewater. These results suggest that the microbes had acclimatized to the recalcitrant wastewater degradation. The high removal rates of both COD carbon and COD others were sustained when the proportion of labile wastewater in the substrate was 33%, indicating that the effective removal of recalcitrant COD might be controlled by changing the substrate's degradability.

  15. Optimal planning of LEO active debris removal based on hybrid optimal control theory

    NASA Astrophysics Data System (ADS)

    Yu, Jing; Chen, Xiao-qian; Chen, Li-hu

    2015-06-01

    The mission planning of Low Earth Orbit (LEO) active debris removal problem is studied in this paper. Specifically, the Servicing Spacecraft (SSc) and several debris exist on near-circular near-coplanar LEOs. The SSc should repeatedly rendezvous with the debris, and de-orbit them until all debris are removed. Considering the long-duration effect of J2 perturbation, a linear dynamics model is used for each rendezvous. The purpose of this paper is to find the optimal service sequence and rendezvous path with minimum total rendezvous cost (Δv) for the whole mission, and some complex constraints (communication time window constraint, terminal state constraint, and time distribution constraint) should be satisfied meanwhile. Considering this mission as a hybrid optimal control problem, a mathematical model is proposed, as well as the solution method. The proposed approach is demonstrated by a typical active debris removal problem. Numerical experiments show that (1) the model and solution method proposed in this paper can effectively address the planning problem of LEO debris removal; (2) the communication time window constraint and the J2 perturbation have considerable influences on the optimization results; and (3) under the same configuration, some suboptimal sequences are equivalent to the optimal one since their difference in Δv cost is very small.

  16. Escherichia coli removal in biochar-augmented biofilter: effect of infiltration rate, initial bacterial concentration, biochar particle size, and presence of compost.

    PubMed

    Mohanty, Sanjay K; Boehm, Alexandria B

    2014-10-07

    Bioretention systems and biofilters are used in low impact development to passively treat urban stormwater. However, these engineered natural systems are not efficient at removing fecal indicator bacteria, the contaminants responsible for a majority of surface water impairments. The present study investigates the efficacy of biochar-augmented model sand biofilters for Escherichia coli removal under a variety of stormwater bacterial concentrations and infiltration rates. Additionally, we test the role of biochar particle size and "presence of compost on model" biofilter performance. Our results show that E. coli removal in a biochar-augmented sand biofilter is ∼ 96% and is not greatly affected by increases in stormwater infiltration rates and influent bacterial concentrations, particularly within the ranges expected in field. Removal of fine (<125 μm) biochar particles from the biochar-sand biofilter decreased the removal capacity from 95% to 62%, indicating biochar size is important. Addition of compost to biochar-sand biofilters not only lowered E. coli removal capacity but also increased the mobilization of deposited bacteria during intermittent infiltration. This result is attributed to exhaustion of attachment sites on biochar by the dissolved organic carbon leached from compost. Overall, our study indicates that biochar has potential to remove bacteria from stormwater under a wide range of field conditions, but for biochar to be effective, the size should be small and biochar should be applied without compost. Although the results aid in the optimization of biofilter design, further studies are needed to examine biochar potential in the field over an entire rainy season.

  17. Reconstitutable control assembly having removable control rods with detachable split upper end plugs

    SciTech Connect

    Gjertsen, R.K.; Knott, R.P.; Sparrow, J.A.

    1989-12-19

    This patent describes, in a reconstitutable control assembly for use with a nuclear fuel assembly, the control assembly including a spider structure and at least one control rod, an attachment joint for detachable fastening the control rod to the spider structure. The attachment joint comprising: a hollow connecting finger on the spider structure; and an elongated detachable split upper end plug on the control rod having a pair of separate upper and lower plug portions, the upper plug portion having integrally-connected tandemly- arranged upper, middle and lower sections. The lower plug portion having integrally-connected tandemly-arranged upper, middle and lower segments.

  18. Control of the aeration volume in an activated sludge process for nitrogen removal.

    PubMed

    Samuelsson, P; Carlsson, B

    2002-01-01

    Biological nitrogen removal in an activated sludge process is obtained by two biological processes; nitrification and denitrification. Nitrifying bacteria need dissolved oxygen and a sufficiently large aeration volume for converting ammonium to nitrate in the wastewater. The objective of this paper is to develop an automatic control strategy for adjusting the aerated volume so that the effluent ammonium level can be kept close to a desired value despite major changes in the influent load. The strategy is based on applying exact linearization of the IAWO Activated Sludge Process Model No 1. Simulation results show that the suggested controller effectively attenuates process disturbances.

  19. Preoperative hair removal and surgical site infections: network meta-analysis of randomized controlled trials.

    PubMed

    Lefebvre, A; Saliou, P; Lucet, J C; Mimoz, O; Keita-Perse, O; Grandbastien, B; Bruyère, F; Boisrenoult, P; Lepelletier, D; Aho-Glélé, L S

    2015-10-01

    Preoperative hair removal has been used to prevent surgical site infections (SSIs) or to prevent hair from interfering with the incision site. We aimed to update the meta-analysis of published randomized controlled trials about hair removal for the prevention of SSIs, and conduct network meta-analyses to combine direct and indirect evidence and to compare chemical depilation with clipping. The PubMed, ScienceDirect and Cochrane databases were searched for randomized controlled trials analysing different hair removal techniques and no hair removal in similar groups. Paired and network meta-analyses were conducted. Two readers independently assessed the study limitations for each selected article according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method. Nineteen studies met the inclusion criteria. No study compared clipping with chemical depilation. Network meta-analyses with shaving as the reference showed significantly fewer SSIs with clipping, chemical depilation, or no depilation [relative risk 0.55, 95% confidence interval 0.38-0.79; 0.60, 0.36-0.97; and 0.56, 0.34-0.96, respectively]. No significant difference was observed between the absence of depilation and chemical depilation or clipping (1.05, 0.55-2.00; 0.97, 0.51-1.82, respectively] or between chemical depilation and clipping (1.09, 0.59-2.01). This meta-analysis of 19 randomized controlled trials confirmed the absence of any benefit of depilation to prevent surgical site infection, and the higher risk of surgical site infection when shaving is used for depilation. Chemical depilation and clipping were compared for the first time. The risk of SSI seems to be similar with both methods.

  20. Inspection Report on "Internal Controls over Accountable Classified Removable Electronic Media at Oak Ridge National Laboratory"

    SciTech Connect

    2009-05-01

    The Department of Energy's Oak Ridge National Laboratory (ORNL) conducts cutting edge scientific research. ORNL utilizes removable electronic media, such as computer hard drives, compact disks, data tapes, etc., to store vast amounts of classified information. Incidents involving breakdowns in controls over classified removable electronic media have been a continuous challenge for the Department. The loss of even one piece of such media can have serious national security implications. In 2004, the Department had a complex-wide 'stand-down' of all activities using classified removable electronic media, and such media containing Secret/Restricted Data or higher classified data was designated 'Accountable Classified Removable Electronic Media' (ACREM). As part of the stand-down, sites were required to conduct a 100 percent physical inventory of all ACREM; enter it all into accountability; and conduct security procedure reviews and training. Further, the Department implemented a series of controls, including conducting periodic inventories, utilizing tamper proof devices on ACREM safes, and appointing trained custodians to be responsible for the material. After performance testing and validation that the required accountability systems were in place, ACREM operations at ORNL were approved for restart on August 10, 2004. We conducted a review at ORNL and associated facilities to determine whether ACREM is managed, protected, and controlled consistent with applicable requirements. We found that: (1) Eight pieces of Secret/Restricted Data media had not been identified as ACREM and placed into a system of accountability. Consequently, the items were not subject to all required protections and controls, such as periodic accountability inventories, oversight by a trained custodian, or storage in a designated ACREM safe. (However, the items were secured in safes approved for classified material.) (2) Other required ACREM protections and controls were not implemented as

  1. Passivation of pigment particles for thermal control coatings

    NASA Technical Reports Server (NTRS)

    Farley, E. P.; Sancier, K. M.; Morrison, S. R.

    1973-01-01

    Five powders were received for plasma calcining during this report period. The particle size using a fluid energy mill, and obtained pigments that could be plasma calcined. Optimum results are obtained in the plasma calcining of zinc orthotitanate when finely dispersed particles are subjected to a calculated plasma temperature of 1670 C. Increasing the plasma calcining time by using multiple passes through the plasma stabilized the pigment to vacuum UV irradiation was evidenced by the resulting ESR spectra but slightly decreased the whiteness of the pigment. The observed darkening is apparently associated with the formation of Ti(+3) color centers.

  2. Enhanced control of fine particles following Title IV coal switching and NOx control

    SciTech Connect

    Durham, M.D.; Baldrey, K.E.; Bustard, C.J.; Martin, C.

    1997-12-31

    Electrostatic precipitators (ESPs) serve as the primary particle control devices for a majority of coal-fired power generating units in the United States. ESPs are used to collect particulate matter that range in size from less than one micrometer in diameter to several hundred micrometers. Many of the options that utilities will use to respond to Title IV of the 1990 Clean Air Act Amendments will result in changes to the ash that will be detrimental to the performance of the ESP causing increased emissions of fine particles and higher opacity. For example, a switch to low-sulfur coal significantly increases particle resistivity while low-NO{sub x} burners increase the carbon content of ashes. Both of these changes could result in derating of the boiler to comply with emissions standards. ADA has developed a chemical additive that is designed to improve the operation of ESI`s to bring these systems into compliance operation without the need for expensive capital modifications. The additives provide advantages over competing technologies in terms of low capital cost, easy to handle chemicals, and relatively non-toxic chemicals. In addition, the new additive is insensitive to ash chemistry which will allow the utility complete flexibility to select the most economical coal. Results from full-scale and pilot plant demonstrations are reported.

  3. Removal of 17beta-estradiol (E2) and its chlorination by-products from water and wastewater using non-imprinted polymer (NIP) particles.

    PubMed

    Murray, Audrey; Ormeci, Banu; Lai, E P C

    2011-01-01

    Endocrine disrupting compounds and their chlorination by-products are two classes of emerging contaminants. Surface water and wastewater treatment technologies have limitations in removing these contaminants. This study evaluated the ability of non-imprinted polymer particles (NIP) to remove the endocrine disruptor 17beta-estradiol (E2) and its chlorination by-products from water and wastewater. NIP effectively removed 98% of 10 mg/L E2 from wastewater. NIP were also effective in removing chlorination by-products of E2 by 84.9% after 10 mg/L E2 in water was chlorinated at 5 mg/L. In the presence of 5 mg/L humic acid, NIP were able to achieve removal of 10 mg/L E2 by greater than 99.9%. Furthermore, after chlorination of 10 mg/L E2 and 5 mg/L humic acid at 10 mg/L chlorine, NIP were also able to remove the chlorination by-products formed as well as the remaining E2 by greater than 99.9%. The presence of 5 mg/L humic acid did not adversely affect the adsorption efficiency. The results of this research indicate that NIPs have good potential as a final treatment step for surface water and wastewater treatment.

  4. Demolition and removal of radioactively contaminated concrete soil: Aerosol control and monitoring

    SciTech Connect

    Newton, G.J.; Hoover, M.D.; Grace, A.C. III

    1995-12-01

    From 1963 to 1985, two concrete-lined ponds were used to reduce the volume of radioactive liquids from the Institute`s research programs. Following withdrawal of the {open_quotes}hot ponds{close_quotes} from active use, the residual sludges and plastic liners of the ponds were removed and shipped to a radioactive waste disposal site. From 1987 to 1994, the concrete structures remained undisturbed pending environmental restoration on the site. Restoration began in 1994 and was completed in 1995. Restoration involved mechanical breakup and removal of the concrete structures and removal of areas of contaminated soils from the site. This report describes the design and results of the aerosol control and monitoring program that was conducted to ensure protection of workers and the environment during the restoration process. The aerosol control and monitoring strategy developed for remediation of the ITRI hot ponds was successful both in preventing dispersion of radioactive dusts and in demonstrating that exposures of workers and offsite releases were within statutory limits.

  5. Kaolin-based particle films for arthropod control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Particle film technology was conceived by ARS scientists in the mid-1990's as an alternative to chemical pesticides. This technology was based on coating plant parts with mineral films that were chemically inert, could be formulated to spread and create a uniform film, formed a porous film that doe...

  6. Particle Size Control for PIV Seeding Using Dry Ice

    DTIC Science & Technology

    2010-03-01

    in flight actually being carried out, the observations, drawings and notes of Leonardo da Vinci showed an analytical process to develop a way for...theoretical particle response: dvp dt = −C(vp − U) C = 18µ ρpd2p 86 87 Bibliography 1. Linscott, R. N. and Da Vinci , L., The Notebooks of Leonardo Da Vinci

  7. Synthesizing Aluminum Particles Towards Controlling Electrostatic Discharge Ignition Sensitivity

    DTIC Science & Technology

    2014-01-01

    electrical resistivity measurements of the mixture which increased with alumina concentration. A model was developed using COMSOL for ignition of a...correlated with electrical resistivity measurements of the mixture which increased with alumina concentration. A model was developed using COMSOL ...was developed using COMSOL for ignition of a single Al particle. The ignition delay in the model was consistent with the experimental results

  8. Developing real-time control software for Space Station Freedom carbon dioxide removal

    NASA Technical Reports Server (NTRS)

    Rowe, Steven A.; Morando, Alexander R.; Johnson, Jim

    1991-01-01

    This paper presents AiResearch experience to date in using the NASA/Boeing Application Generator (AG) to develop real-time control systems for the Carbon Dioxide Removal Assembly (CDRA) in Work Package 01. The AG provides an integrated design and development tool encompassing: system analysis, modeling, control law design, simulation, code generation, real-time hardware-in-the-loop simulation and operation, and documentation. This allows rapid interactive prototyping of real-time control systems in a single, integrated, environment. Advantages and disadvantages of using the AG for real-time control system development will be addressed, with the CDRA specification to delivery cycle serving as a basis for discussion. Suggestions for improving the AG are offered and observations on its potential as a top-level system specification tool are made.

  9. Reconstitutable control assembly having removable control rods with detachable split upper end plugs

    SciTech Connect

    Gjertsen, R.K.; Knott, R.P.; Sparrow, J.A.

    1991-02-19

    This patent describes, for use in facilitating replacement of a neutron absorber control rod on a control assembly spider structure, an end plug. It comprises a pair of separate upper and lower plug portions; the upper section of the upper plug portion being configured for rigid attachment; the middle section of the upper plug portion having angularly displaced flat surfaces formed on the exterior.

  10. Synthesis of green nano iron particles (GnIP) and their application in adsorptive removal of As(III) and As(V) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Prasad, Kumar Suranjit; Gandhi, Pooja; Selvaraj, Kaliaperumal

    2014-10-01

    The present study reports a new approach to synthesise nano iron particles using leaf extract of Mint (Mentha spicata L.) plant. The synthesised GnIPs were subjected to detailed adsorption studies for removal of arsenite and arsenate from aqueous solution of defined concentration. Iron nanoparticles synthesised using leaf extract showed UV-vis absorption peaks at 360 and 430 nm. TEM result showed the formation of polydispersed nanoparticles of size ranging from 20 to 45 nm. Nanoparticles were found to have core-shell structure. The planer reflection of selected area electron diffraction (SAED) and XRD analysis suggested that iron particles were crystalline and belonged to fcc (face centred cubic) type. Energy-dispersive X-ray analysis (EDAX) shows that Fe was an integral component of synthesised nanoparticles. The content of Fe in nanoparticles was found to be 40%, in addition to other elements like C (16%), O (19%) and Cl (23%). FT-IR study suggested that functional groups like sbnd NH, sbnd Cdbnd O, sbnd Cdbnd N and sbnd Cdbnd C were involved in particle formation. The removal efficiency of GnIP-chitosan composite for As(III) and As(V) was found to be 98.79 and 99.65%. Regeneration of adsorbent suggested that synthesised green GnIP may work as an effective tool for removal of arsenic from contaminated water.

  11. Simple synthesis of smart magnetically driven fibrous films for remote controllable oil removal

    NASA Astrophysics Data System (ADS)

    Wu, Jing; Wang, Nü; Zhao, Yong; Jiang, Lei

    2015-01-01

    Inspired by the marine mussel adhesive protein, smart, magnetically controllable, oil adsorption nanofibrous materials were successfully fabricated in this research. Taking advantage of the properties of dopamine whose molecular structure mimics the single unit of the marine mussel adhesive protein and can be polymerized in alkaline solution forming a ``glue'' layer on many kinds of material surfaces, magnetic iron(ii, iii) oxide (Fe3O4) nanoparticles were easily and robustly anchored on to electrospun poly(vinylidene fluoride) fibrous films. After fluorination, the as-prepared hierarchical structured films exhibited superhydrophobicity, superoleophilicity and an excellent oil adsorption capacity from water. Importantly, because of the magnetically controllable property endowed by the Fe3O4 nanoparticles, such fibrous films act as a ``smart magnetically controlled oil removal carrier'', which effectively overcome the drawbacks of other in situ oil adsorbant materials and can also be easily recovered. This work provides a simple strategy to fabricate magnetic responsive intelligent oil removal materials, which will find broad applications in complex environment oil-water separation.Inspired by the marine mussel adhesive protein, smart, magnetically controllable, oil adsorption nanofibrous materials were successfully fabricated in this research. Taking advantage of the properties of dopamine whose molecular structure mimics the single unit of the marine mussel adhesive protein and can be polymerized in alkaline solution forming a ``glue'' layer on many kinds of material surfaces, magnetic iron(ii, iii) oxide (Fe3O4) nanoparticles were easily and robustly anchored on to electrospun poly(vinylidene fluoride) fibrous films. After fluorination, the as-prepared hierarchical structured films exhibited superhydrophobicity, superoleophilicity and an excellent oil adsorption capacity from water. Importantly, because of the magnetically controllable property endowed by the Fe3

  12. THE EFFECT OF WATER CHEMISTRY AND IRON PARTICLE PROPERTIES ON THE REMOVAL OF ARSENIC FOLLOWING THE OXIDATION OF FERROUS IRON

    EPA Science Inventory

    The current MCL for arsenic is being revised to a lower level by the USEPA. Many new utilities, particularly small utilities, will be forced to add an arsenic removal process or fine tune their curent water treatment process to meet the new MCL. Many arsenic removal processes rel...

  13. Humic substances interfere with phosphate removal by Lanthanum modified clay in controlling eutrophication.

    PubMed

    Lürling, Miquel; Waajen, Guido; van Oosterhout, Frank

    2014-05-01

    The lanthanum (La) modified bentonite Phoslock(®) has been proposed as dephosphatisation technique aiming at removing Filterable Reactive Phosphorus (FRP) from the water and blocking the release of FRP from the sediment. In the modified clay La is expected the active ingredient. We conducted controlled laboratory experiments to measure the FRP removal by Phoslock(®) in the presence and absence of humic substances, as La complexation with humic substances might lower the effectiveness of La (Phoslock(®)) to bind FRP. The results of our study support the hypothesis that the presence of humic substances can interfere with the FRP removal by the La-modified bentonite. Both a short-term (1 d) and long-term (42 d) experiment were in agreement with predictions derived from chemical equilibrium modelling and showed lower FRP removal in presence of humic substances. This implies that in DOC-rich inland waters the applicability of exclusively Phoslock(®) as FRP binder should be met critically. In addition, we observed a strong increase of filterable La in presence of humic substances reaching in a week more than 270 μg La l(-1) that would infer a violation of the Dutch La standard for surface water, which is 10.1 μg La l(-1). Hence, humic substances are an important factor that should be given attention when considering chemical FRP inactivation as they might play a substantial role in lowering the efficacy of metal-based FRP-sorbents, which makes measurements of humic substances (DOC) as well as controlled experiments vital.

  14. Controlling the scattering properties of thin, particle-doped coatings

    NASA Astrophysics Data System (ADS)

    Rogers, William; Corbett, Madeleine; Manoharan, Vinothan

    2013-03-01

    Coatings and thin films of small particles suspended in a matrix possess optical properties that are important in several industries from cosmetics and paints to polymer composites. Many of the most interesting applications require coatings that produce several bulk effects simultaneously, but it is often difficult to rationally formulate materials with these desired optical properties. Here, we focus on the specific challenge of designing a thin colloidal film that maximizes both diffuse and total hemispherical transmission. We demonstrate that these bulk optical properties follow a simple scaling with two microscopic length scales: the scattering and transport mean free paths. Using these length scales and Mie scattering calculations, we generate basic design rules that relate scattering at the single particle level to the film's bulk optical properties. These ideas will be useful in the rational design of future optically active coatings.

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

    PubMed

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

    2016-08-21

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

  16. Electrooptical behaviour and control of a suspended particle device

    NASA Astrophysics Data System (ADS)

    Vergaz, R.; Pena, J. M. S.; Barrios, D.; Pérez, I.; Torres, J. C.

    2007-09-01

    A suspended particle device is made by electrophoretic rod-shape particles suspended in an organic gel. These particles can twist and order with an applied voltage. The light crossing the material suffers more or less scattering according to that voltage. A commercial device is analyzed in this work. Several electrical models are tested, being the best one a series configuration including a shunt double layer capacitance and a Warburg element. Main parameter errors are below 2%, showing the quality of this new electrical model for this kind of devices. A quick method to improve the manufacturing process on-line is also proposed. Impedance measurements will be fitted to the selected electrical model, in order to check physical aspects such as charge diffusion lengths and response times. An electronic driver to obtain several levels of device transmission has been also developed, being its linearity demonstrated too. Colour changes are negligible for the main part of the bleaching process. All these features allow the use of this set in domotics application.

  17. 40 CFR 63.3966 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the add-on control... Emission Rate with Add-on Controls Option § 63.3966 How do I determine the add-on control device emission... the add-on control device emission destruction or removal efficiency as part of the performance...

  18. 40 CFR 63.4566 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the add-on control... with Add-on Controls Option § 63.4566 How do I determine the add-on control device emission destruction... add-on control device emission destruction or removal efficiency as part of the performance...

  19. 40 CFR 63.3966 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the add-on control... Emission Rate with Add-on Controls Option § 63.3966 How do I determine the add-on control device emission... the add-on control device emission destruction or removal efficiency as part of the performance...

  20. 40 CFR 63.4566 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the add-on control... with Add-on Controls Option § 63.4566 How do I determine the add-on control device emission destruction... add-on control device emission destruction or removal efficiency as part of the performance...

  1. 40 CFR 63.4566 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the add-on control... with Add-on Controls Option § 63.4566 How do I determine the add-on control device emission destruction... add-on control device emission destruction or removal efficiency as part of the performance...

  2. 40 CFR 63.3966 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the add-on control... Emission Rate with Add-on Controls Option § 63.3966 How do I determine the add-on control device emission... the add-on control device emission destruction or removal efficiency as part of the performance...

  3. 40 CFR 63.3966 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... with Add-on Controls Option § 63.3966 How do I determine the add-on control device emission destruction... add-on control device emission destruction or removal efficiency as part of the performance...

  4. Controlling self-sustained spiking activity by adding or removing one network link

    NASA Astrophysics Data System (ADS)

    Xu, Kesheng; Huang, Wenwen; Li, Baowen; Dhamala, Mukesh; Liu, Zonghua

    2013-06-01

    Being able to control the neuronal spiking activity in specific brain regions is central to a treatment scheme in several brain disorders such as epileptic seizures, mental depression, and Parkinson's diseases. Here, we present an approach for controlling self-sustained oscillations by adding or removing one directed network link in coupled neuronal oscillators, in contrast to previous approaches of adding stimuli or noise. We find that such networks can exhibit a variety of activity patterns such as on-off switch, sustained spikes, and short-term spikes. We derive the condition for a specific link to be the controller of the on-off effect. A qualitative analysis is provided to facilitate the understanding of the mechanism for spiking activity by adding one link. Our findings represent the first report on generating spike activity with the addition of only one directed link to a network and provide a deeper understanding of the microscopic roots of self-sustained spiking.

  5. Pattern formation and flow control of fine particles by laser-scanning micromanipulation.

    PubMed

    Sasaki, K; Koshioka, M; Misawa, H; Kitamura, N; Masuhara, H

    1991-10-01

    A novel micromanipulation technique is proposed for aligning fine particles on micrometer-scale spatial patterns and for moving the particles continuously along the formed patterns. This technique is based on the repetitive scanning of a focused trapping laser beam. The velocity of the particle flow can be controlled by scan speed and laser power. The origin of the driving force is considered theoretically and experimentally.

  6. Simple synthesis of smart magnetically driven fibrous films for remote controllable oil removal.

    PubMed

    Wu, Jing; Wang, Nü; Zhao, Yong; Jiang, Lei

    2015-02-14

    Inspired by the marine mussel adhesive protein, smart, magnetically controllable, oil adsorption nanofibrous materials were successfully fabricated in this research. Taking advantage of the properties of dopamine whose molecular structure mimics the single unit of the marine mussel adhesive protein and can be polymerized in alkaline solution forming a "glue" layer on many kinds of material surfaces, magnetic iron(II, III) oxide (Fe3O4) nanoparticles were easily and robustly anchored on to electrospun poly(vinylidene fluoride) fibrous films. After fluorination, the as-prepared hierarchical structured films exhibited superhydrophobicity, superoleophilicity and an excellent oil adsorption capacity from water. Importantly, because of the magnetically controllable property endowed by the Fe3O4 nanoparticles, such fibrous films act as a "smart magnetically controlled oil removal carrier", which effectively overcome the drawbacks of other in situ oil adsorbant materials and can also be easily recovered. This work provides a simple strategy to fabricate magnetic responsive intelligent oil removal materials, which will find broad applications in complex environment oil-water separation.

  7. Removal of antibiotics from water in the coexistence of suspended particles and natural organic matters using amino-acid-modified-chitosan flocculants: A combined experimental and theoretical study.

    PubMed

    Jia, Shuying; Yang, Zhen; Ren, Kexin; Tian, Ziqi; Dong, Chang; Ma, Ruixue; Yu, Ge; Yang, Weiben

    2016-11-05

    Contamination of trace antibiotics is widely found in surface water sources. This work delineates removal of trace antibiotics (norfloxacin (NOR), sulfadiazine (SDZ) or tylosin (TYL)) from synthetic surface water by flocculation, in the coexistence of inorganic suspended particles (kaolin) and natural organic matter (humic acid, HA). To avoid extra pollution caused by petrochemical products-based modification reagents, environmental-friendly amino-acid-modified-chitosan flocculants, Ctrp and Ctyr, with different functional aromatic-rings structures were employed. Jar tests at various pHs exhibited that, Ctyr, owning phenol groups as electron donors, was favored for elimination of cationic NOR (∼50% removal; optimal pH: 6; optimal dosage: 4mg/L) and TYL (∼60% removal; optimal pH: 7; optimal dosage: 7.5mg/L), due to π-π electron donator-acceptor (EDA) effect and unconventional H-bonds. Differently, Ctrp with indole groups as electron acceptor had better removal rate (∼50%) of SDZ anions (electron donator). According to correlation analysis, the coexisted kaolin and HA played positive roles in antibiotics' removal. Detailed pairwise interactions in molecular level among different components were clarified by spectral analysis and theoretical calculations (density functional theory), which are important for both the structural design of new flocculants aiming at targeted contaminants and understanding the environmental behaviors of antibiotics in water.

  8. Modification of an Iranian clinoptilolite nano-particles by hexadecyltrimethyl ammonium cationic surfactant and dithizone for removal of Pb(II) from aqueous solution.

    PubMed

    Anari-Anaraki, Mostafa; Nezamzadeh-Ejhieh, Alireza

    2015-02-15

    Natural clinoptilolite tuff was mechanically converted to micro (MCP) and nano (NCP) particles. The MCP and NCP powders were respectively modified with hexadecyltrimethyl ammonium bromide (HDTMA) and dithizone (DTZ). The raw and modified samples were characterized by X-ray diffraction (XRD), Fourier transformation infra red (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM) and thermogravimetry (TG) and used for the removal of Pb(II) from aqueous solution. The results confirm that both ion exchange and complexation processes are responsible for removal of Pb(II) cations in the modified samples, while Pb(II) cations were only removed via an ion exchange process by the raw clinoptilolite. In this sorbent, the anionic removal property of surfactant modified zeolites (SMZs) changed to cationic removal property by an additional modification step. The best removal efficiency was observed by NCP-HDTMA-DTZ at the following experimental conditions: C(Pb(II)): 800 mg L(-1), HDTMA dosage: 0.2 mol L(-1), DTZ dosage: 5 mmol L(-1), contact time of DTZ with NCP-HDTMA: 1800 min and contact time of the sorbent with Pb(II): 360 min. The NCP-HDTMA-DTZ sorbent showed good efficiency for the removal of lead in the presence of different multivalent cations. Adsorption isotherms of Pb(II) ions obey the Langmuir equation that indicate the monolayer sorption of Pb(II). The adsorption kinetics based on the pseudo-second-order rate equation indicates that the rate limiting step involving a chemical reaction. The negative ΔH and ΔG indicate an exothermic and spontaneous process.

  9. Modeling the Controlled Recrystallization of Particle-Containing Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Adam, Khaled; Root, Jameson M.; Long, Zhengdong; Field, David P.

    2017-01-01

    The recrystallized fraction for AA7050 during the solution heat treatment is highly dependent upon the history of deformation during thermomechanical processing. In this work, a state variable model was developed to predict the recrystallization volume fraction as a function of processing parameters. Particle stimulated nucleation (PSN) was observed as a dominant mechanism of recrystallization in AA7050. The mesoscale Monte Carlo Potts model was used to simulate the evolved microstructure during static recrystallization with the given recrystallization fraction determined already by the state variable model for AA7050 alloy. The spatial inhomogeneity of nucleation is obtained from the measurement of the actual second-phase particle distribution in the matrix identified using backscattered electron (BSE) imaging. The state variable model showed good fit with the experimental results, and the simulated microstructures were quantitatively comparable to the experimental results for the PSN recrystallized microstructure of 7050 aluminum alloy. It was also found that the volume fraction of recrystallization did not proceed as dictated by the Avrami equation in this alloy because of the presence of the growth inhibitors.

  10. Hydrodynamic controls on particle transport through heterogeneous porous media

    SciTech Connect

    Silliman, S.E.

    1992-09-30

    The initial stages of this project have been focused on equipment development and preliminary experimental efforts. Among the accomplishments to date are the development of a successful flow cell design, proof of the utility of the UV resin, adjustment of the Laser Particle Counter to produce reliable readings, installation of a low particle content water supply, installation of a microscope for viewing discharge samples, development of a fiber/rod optic system for freezing the UV resin in situ and performance of initial experiments on layered and complex heterogeneities. The work is currently following very closely the original schedule for research efforts. Continuing efforts in year one will include continued efforts in simple and complex heterogeneity in two-dimensions, extension into three-dimensions, consideration of the most appropriate methods for creating geologically realistic structures in the laboratory, interaction with other SSP research programs and organization of the spring meeting on intermediate-scale experimentation to be held at Notre Dame. Efforts in year two will be focused on three-dimensional experiments in saturated media, extension of results into unsaturated media, development of techniques for unsaturated media characterization, and development of research ties with outside research interests.

  11. Modeling the Controlled Recrystallization of Particle-Containing Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Adam, Khaled; Root, Jameson M.; Long, Zhengdong; Field, David P.

    2016-12-01

    The recrystallized fraction for AA7050 during the solution heat treatment is highly dependent upon the history of deformation during thermomechanical processing. In this work, a state variable model was developed to predict the recrystallization volume fraction as a function of processing parameters. Particle stimulated nucleation (PSN) was observed as a dominant mechanism of recrystallization in AA7050. The mesoscale Monte Carlo Potts model was used to simulate the evolved microstructure during static recrystallization with the given recrystallization fraction determined already by the state variable model for AA7050 alloy. The spatial inhomogeneity of nucleation is obtained from the measurement of the actual second-phase particle distribution in the matrix identified using backscattered electron (BSE) imaging. The state variable model showed good fit with the experimental results, and the simulated microstructures were quantitatively comparable to the experimental results for the PSN recrystallized microstructure of 7050 aluminum alloy. It was also found that the volume fraction of recrystallization did not proceed as dictated by the Avrami equation in this alloy because of the presence of the growth inhibitors.

  12. Tracking control of colloidal particles through non-homogeneous stationary flows

    SciTech Connect

    Híjar, Humberto

    2013-12-21

    We consider the problem of controlling the trajectory of a single colloidal particle in a fluid with steady non-homogeneous flow. We use a Langevin equation to describe the dynamics of this particle, where the friction term is assumed to be given by the Faxén's Theorem for the force on a sphere immersed in a stationary flow. We use this description to propose an explicit control force field to be applied on the particle such that it will follow asymptotically any given desired trajectory, starting from an arbitrary initial condition. We show that the dynamics of the controlled particle can be mapped into a set of stochastic harmonic oscillators and that the velocity gradient of the solvent induces an asymmetric coupling between them. We study the particular case of a Brownian particle controlled through a plane Couette flow and show explicitly that the velocity gradient of the solvent renders the dynamics non-stationary and non-reversible in time. We quantify this effect in terms of the correlation functions for the position of the controlled particle, which turn out to exhibit contributions depending exclusively on the non-equilibrium character of the state of the solvent. In order to test the validity of our model, we perform simulations of the controlled particle moving in a simple shear flow, using a hybrid method combining molecular dynamics and multi-particle collision dynamics. We confirm numerically that the proposed guiding force allows for controlling the trajectory of the micro-sized particle by obligating it to follow diverse specific trajectories in fluids with homogeneous shear rates of different strengths. In addition, we find that the non-equilibrium correlation functions in simulations exhibit the same qualitative behavior predicted by the model, thus revealing the presence of the asymmetric non-equilibrium coupling mechanism induced by the velocity gradient.

  13. Simulating sterilization, vaccination, and test-and-remove as brucellosis control measures in bison

    USGS Publications Warehouse

    Ebinger, M.; Cross, P.; Wallen, Rick; White, P.J.; Treanor, John

    2011-01-01

    Brucella abortus, the causative agent of bovine brucellosis, infects wildlife, cattle, and humans worldwide, but management of the disease is often hindered by the logistics of controlling its prevalence in wildlife reservoirs. We used an individually based epidemiological model to assess the relative efficacies of three management interventions (sterilization, vaccination, and test-and-remove). The model was parameterized with demographic and epidemiological data from bison in Yellowstone National Park, USA. Sterilization and test-and-remove were most successful at reducing seroprevalence when they were targeted at young seropositive animals, which are the most likely age and sex category to be infectious. However, these approaches also required the most effort to implement. Vaccination was less effective (even with a perfect vaccine) but also required less effort to implement. For the treatment efforts we explored (50–100 individuals per year or 2.5–5% of the female population), sterilization had little impact upon the bison population growth rate when selectively applied. The population growth rate usually increased by year 25 due to the reduced number of Brucella-induced abortions. Initial declines in seroprevalence followed by rapid increases (>15% increase in 5 years) occurred in 3–13% of simulations with sterilization and test-and-remove, but not vaccination. We believe this is due to the interaction of superspreading events and the loss of herd immunity in the later stages of control efforts as disease prevalence declines. Sterilization provided a mechanism for achieving large disease reductions while simultaneously limiting population growth, which may be advantageous in some management scenarios. However, the field effort required to find the small segment of the population that is infectious rather than susceptible or recovered will likely limit the utility of this approach in many free-ranging wildlife populations. Nevertheless, we encourage

  14. Minimizing nitrous oxide in biological nutrient removal from municipal wastewater by controlling copper ion concentrations.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang; Chen, Hong; Li, Xiang; Peng, Yongzhen; Wang, Shuying

    2013-02-01

    In this study, nitrous oxide (N(2)O) production during biological nutrient removal (BNR) from municipal wastewater was reported to be remarkably reduced by controlling copper ion (Cu(2+)) concentration. Firstly, it was observed that the addition of Cu(2+) (10-100 μg/L) reduced N(2)O generation by 54.5-73.2 % and improved total nitrogen removal when synthetic wastewater was treated in an anaerobic-aerobic (with low dissolved oxygen) BNR process. Then, the roles of Cu(2+) were investigated. The activities of nitrite and nitrous oxide reductases were increased by Cu(2+) addition, which accelerated the bio-reductions of both nitrite to nitric oxide (NO (2) (-)  → NO) and nitrous oxide to nitrogen gas (N(2)O → N(2)). The quantitative real-time polymerase chain reaction assay indicated that Cu(2+) addition increased the number of N(2)O reducing denitrifiers. Further investigation showed that more polyhydoxyalkanoates were utilized in the Cu(2+)-added system for denitrification. Finally, the feasibility of reducing N(2)O generation by controlling Cu(2+) was examined in two other BNR processes treating real municipal wastewater. As the Cu(2+) in municipal wastewater is usually below 10 μg/L, according to this study, the supplement of influent Cu(2+) to a concentration of 10-100 μg/L is beneficial to reduce N(2)O emission and improve nitrogen removal when sludge concentration in the BNR system is around 3,200 mg/L.

  15. Chronocoulometry for quantitative control of mass removal in micro-structures and sensors

    SciTech Connect

    Nowakowski, B. K.; Smith, S. T.; Pratt, J. R.; Shaw, G. A.

    2012-10-15

    In this work, tungsten wires have been etched in a KOH electrolyte solution. Based on the oxidation state of the electrolytic dissolution reaction's product and time integration of the Faradaic current produced during the reaction, this method is capable of providing a direct measurement of the change in mass of a structure from anodic dissolution. To assess the application of this process for controlled mass removal spanning sub-micrograms to milligrams, two experimental studies and accompanying uncertainty analyses have been undertaken. In the first of these, 5 tungsten wires of length 30 mm were used to remove mass values ranging from 50 to 350 {mu}g. Uncertainty estimates indicate relative combined standard uncertainties of less than 0.3% in the mass changes determined from the measurement of Faradaic current. Comparison of the mass change determined using the electrolytic method, and using a precision ultra-microbalance agreed within this uncertainty. The charge-based method was then applied to modify the dynamic characteristics of a quartz tuning fork oscillator. In these experiments, tungsten fiber attached to one tine of the oscillator was etched in 5 {mu}g increments up to 120 {mu}g of total removed mass. In general, frequency shifts of 2.8 Hz{center_dot}{mu}g{sup -1} were observed, indicating sub-microgram resolution for the characterization of probes based on frequency shift and charge-based mass measurement. Taken together, this study provides the basis for a precision method for determining changes in mass based on electrical measurements from an electrochemical system. The utility of this technique is demonstrated through controlled modification of the dynamic properties of a mechanical oscillator.

  16. Chronocoulometry for quantitative control of mass removal in micro-structures and sensors

    NASA Astrophysics Data System (ADS)

    Nowakowski, B. K.; Smith, S. T.; Pratt, J. R.; Shaw, G. A.

    2012-10-01

    In this work, tungsten wires have been etched in a KOH electrolyte solution. Based on the oxidation state of the electrolytic dissolution reaction's product and time integration of the Faradaic current produced during the reaction, this method is capable of providing a direct measurement of the change in mass of a structure from anodic dissolution. To assess the application of this process for controlled mass removal spanning sub-micrograms to milligrams, two experimental studies and accompanying uncertainty analyses have been undertaken. In the first of these, 5 tungsten wires of length 30 mm were used to remove mass values ranging from 50 to 350 μg. Uncertainty estimates indicate relative combined standard uncertainties of less than 0.3% in the mass changes determined from the measurement of Faradaic current. Comparison of the mass change determined using the electrolytic method, and using a precision ultra-microbalance agreed within this uncertainty. The charge-based method was then applied to modify the dynamic characteristics of a quartz tuning fork oscillator. In these experiments, tungsten fiber attached to one tine of the oscillator was etched in 5 μg increments up to 120 μg of total removed mass. In general, frequency shifts of 2.8 Hz.μg-1 were observed, indicating sub-microgram resolution for the characterization of probes based on frequency shift and charge-based mass measurement. Taken together, this study provides the basis for a precision method for determining changes in mass based on electrical measurements from an electrochemical system. The utility of this technique is demonstrated through controlled modification of the dynamic properties of a mechanical oscillator.

  17. Facile biofunctionalization of silver nanoparticles for enhanced antibacterial properties, endotoxin removal, and biofilm control

    PubMed Central

    Lambadi, Paramesh Ramulu; Sharma, Tarun Kumar; Kumar, Piyush; Vasnani, Priyanka; Thalluri, Sitaramanjaneya Mouli; Bisht, Neha; Pathania, Ranjana; Navani, Naveen Kumar

    2015-01-01

    Infectious diseases cause a huge burden on healthcare systems worldwide. Pathogenic bacteria establish infection by developing antibiotic resistance and modulating the host’s immune system, whereas opportunistic pathogens like Pseudomonas aeruginosa adapt to adverse conditions owing to their ability to form biofilms. In the present study, silver nanoparticles were biofunctionalized with polymyxin B, an antibacterial peptide using a facile method. The biofunctionalized nanoparticles (polymyxin B-capped silver nanoparticles, PBSNPs) were assessed for antibacterial activity against multiple drug-resistant clinical strain Vibrio fluvialis and nosocomial pathogen P. aeruginosa. The results of antibacterial assay revealed that PBSNPs had an approximately 3-fold higher effect than the citrate-capped nanoparticles (CSNPs). Morphological damage to the cell membrane was followed by scanning electron microscopy, testifying PBSNPs to be more potent in controlling the bacterial growth as compared with CSNPs. The bactericidal effect of PBSNPs was further confirmed by Live/Dead staining assays. Apart from the antibacterial activity, the biofunctionalized nanoparticles were found to resist biofilm formation. Electroplating of PBSNPs onto stainless steel surgical blades retained the antibacterial activity against P. aeruginosa. Further, the affinity of polymyxin for endotoxin was exploited for its removal using PBSNPs. It was found that the prepared nanoparticles removed 97% of the endotoxin from the solution. Such multifarious uses of metal nanoparticles are an attractive means of enhancing the potency of antimicrobial agents to control infections. PMID:25834431

  18. Facile biofunctionalization of silver nanoparticles for enhanced antibacterial properties, endotoxin removal, and biofilm control.

    PubMed

    Lambadi, Paramesh Ramulu; Sharma, Tarun Kumar; Kumar, Piyush; Vasnani, Priyanka; Thalluri, Sitaramanjaneya Mouli; Bisht, Neha; Pathania, Ranjana; Navani, Naveen Kumar

    2015-01-01

    Infectious diseases cause a huge burden on healthcare systems worldwide. Pathogenic bacteria establish infection by developing antibiotic resistance and modulating the host's immune system, whereas opportunistic pathogens like Pseudomonas aeruginosa adapt to adverse conditions owing to their ability to form biofilms. In the present study, silver nanoparticles were biofunctionalized with polymyxin B, an antibacterial peptide using a facile method. The biofunctionalized nanoparticles (polymyxin B-capped silver nanoparticles, PBSNPs) were assessed for antibacterial activity against multiple drug-resistant clinical strain Vibrio fluvialis and nosocomial pathogen P. aeruginosa. The results of antibacterial assay revealed that PBSNPs had an approximately 3-fold higher effect than the citrate-capped nanoparticles (CSNPs). Morphological damage to the cell membrane was followed by scanning electron microscopy, testifying PBSNPs to be more potent in controlling the bacterial growth as compared with CSNPs. The bactericidal effect of PBSNPs was further confirmed by Live/Dead staining assays. Apart from the antibacterial activity, the biofunctionalized nanoparticles were found to resist biofilm formation. Electroplating of PBSNPs onto stainless steel surgical blades retained the antibacterial activity against P. aeruginosa. Further, the affinity of polymyxin for endotoxin was exploited for its removal using PBSNPs. It was found that the prepared nanoparticles removed 97% of the endotoxin from the solution. Such multifarious uses of metal nanoparticles are an attractive means of enhancing the potency of antimicrobial agents to control infections.

  19. Control of binder viscosity and hygroscopicity on particle aggregation efficiency

    NASA Astrophysics Data System (ADS)

    Mueller, Sebastian B.; Kueppers, Ulrich; Ayris, Paul M.; Jacob, Michael; Delmelle, Pierre; Dingwell, Donald B.

    2016-04-01

    In the course of explosive volcanic eruptions, large amounts of ash are released into the atmosphere and may subsequently pose a threat to infrastructure, such as aviation industry. Ash plume forecasting is therefore a crucial tool for volcanic hazard mitigation but may be significantly affected by aggregation, altering the aerodynamic properties of particles. Models struggle with the implementation of aggregation since external conditions promoting aggregation have not been completely understood; in a previous study we have shown the rapid generation of ash aggregates through liquid bonding via the use of fluidization bed technology and further defined humidity and temperature ranges necessary to trigger aggregation. Salt (NaCl) was required for the recovery of stable aggregates, acting as a cementation agent and granting aggregate cohesion. A numerical model was used to explain the physics behind particle aggregation mechanisms and further predicted a dependency of aggregation efficiency on liquid binder viscosity. In this study we proof the effect of viscosity on particle aggregation. HCl and H2SO4 solutions were diluted to various concentrations resulting in viscosities between 1 and 2 mPas. Phonolitic and rhyolitic ash samples as well as soda-lime glass beads (serving as analogue material) were fluidized in the ProCell Lab® of Glatt Ingenieurtechnik GmbH and treated with the acids via a bottom-spray technique. Chemically driven interaction between acid liquids and surfaces of the three used materials led to crystal precipitation. Salt crystals (e.g. NaCl) have been confirmed through scanning electron microscopy (SEM) and leachate analysis. Both volcanic ash samples as well as the glass beads showed a clear dependency of aggregation efficiency on viscosity of the sprayed HCl solution. Spraying H2SO4 provoked a collapse of the fluidized bed and no aggregation has been observed. This is accounted by the high hygroscopicity of H2SO4. Dissolving CaCl2 (known to be

  20. Control and formation mechanism of extended nanochannel geometry in colloidal mesoporous silica particles.

    PubMed

    Sokolov, I; Kalaparthi, V; Volkov, D O; Palantavida, S; Mordvinova, N E; Lebedev, O I; Owens, J

    2017-01-04

    A large class of colloidal multi-micron mesoporous silica particles have well-defined cylindrical nanopores, nanochannels which self-assembled in the templated sol-gel process. These particles are of broad interest in photonics, for timed drug release, enzyme stabilization, separation and filtration technologies, catalysis, etc. Although the pore geometry and mechanism of pore formation of such particles has been widely investigated at the nanoscale, their pore geometry and its formation mechanism at a larger (extended) scale is still under debate. The extended geometry of nanochannels is paramount for all aforementioned applications because it defines accessibility of nanochannels, and subsequently, kinetics of interaction of the nanochannel content with the particle surrounding. Here we present both experimental and theoretical investigation of the extended geometry and its formation mechanism in colloidal multi-micron mesoporous silica particles. We demonstrate that disordered (and consequently, well accessible) nanochannels in the initially formed colloidal particles gradually align and form extended self-sealed channels. This knowledge allows to control the percentage of disordered versus self-sealed nanochannels, which defines accessibility of nanochannels in such particles. We further show that the observed aligning the channels is in agreement with theory; it is thermodynamically favored as it decreases the Gibbs free energy of the particles. Besides the practical use of the obtained results, developing a fundamental understanding of the mechanisms of morphogenesis of complex geometry of nanopores will open doors to efficient and controllable synthesis that will, in turn, further fuel the practical utilization of these particles.

  1. Controlling local order of athermal self-propelled particles

    NASA Astrophysics Data System (ADS)

    Dougan, Niamh; Crowther, Peter; Royall, C. Patrick; Turci, Francesco

    2016-12-01

    We consider a model of self-propelled dynamics for athermal active particles, where the non-equilibrium active forces are modelled by a Ornstein-Uhlenbeck process. In the limit of no-driving force, the model reduces to the passive, Brownian dynamics of an atomistic glass forming fluid, the Wahnström binary mixture. The Wahnström mixture is known to show strong correlations between the emergence of slow dynamics and the formation of locally favoured structures based on icosahedra. Here, we study how the non-equilibrium driving affects the local structure of the system, and find that it strongly promotes icosahedral order. The states rich in local icosahedral order correspond to configurations of very low potential energy, suggesting that the non-equilibrium dynamics in the self propelled model can be effectively exploited to explore the potential energy surface of the binary mixture and have access to states that are difficult to attain using passive dynamics.

  2. Controllable fabrication and magnetic properties of double-shell cobalt oxides hollow particles

    PubMed Central

    Zhang, Dan; Zhu, Jianyu; Zhang, Ning; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Zhang, Haitao; Qiu, Guanzhou

    2015-01-01

    Double-shell cobalt monoxide (CoO) hollow particles were successfully synthesized by a facile and effective one-pot solution-based synthetic route. The inner architecture and outer structure of the double-shell CoO hollow particles could be readily created through controlling experimental parameters. A possible formation mechanism was proposed based on the experimental results. The current synthetic strategy has good prospects for the future production of other transition-metal oxides particles with hollow interior. Furthermore, double-shell cobalt oxide (Co3O4) hollow particles could also be obtained through calcinating corresponding CoO hollow particles. The magnetic measurements revealed double-shell CoO and Co3O4 hollow particles exhibit ferromagnetic and antiferromagnetic behaviour, respectively. PMID:25736824

  3. Controllable fabrication and magnetic properties of double-shell cobalt oxides hollow particles

    NASA Astrophysics Data System (ADS)

    Zhang, Dan; Zhu, Jianyu; Zhang, Ning; Liu, Tao; Chen, Limiao; Liu, Xiaohe; Ma, Renzhi; Zhang, Haitao; Qiu, Guanzhou

    2015-03-01

    Double-shell cobalt monoxide (CoO) hollow particles were successfully synthesized by a facile and effective one-pot solution-based synthetic route. The inner architecture and outer structure of the double-shell CoO hollow particles could be readily created through controlling experimental parameters. A possible formation mechanism was proposed based on the experimental results. The current synthetic strategy has good prospects for the future production of other transition-metal oxides particles with hollow interior. Furthermore, double-shell cobalt oxide (Co3O4) hollow particles could also be obtained through calcinating corresponding CoO hollow particles. The magnetic measurements revealed double-shell CoO and Co3O4 hollow particles exhibit ferromagnetic and antiferromagnetic behaviour, respectively.

  4. Development of a controllable particle generator for LV seeding in hypersonic wind tunnels

    NASA Technical Reports Server (NTRS)

    Feller, W. V.; Meyers, J. F.

    1976-01-01

    The paper describes the considerations that went into the development of a controllable particle generator for laser velocimeter seeding in a hypersonic wind tunnel operating at 3.45 million N/sq m, 533 K, and stream speed of about 1000 m/sec. Operating conditions determined the choice of a silicone oil as the material, and the requirement that the particle follow the flow within a certain accuracy range put constraints on the allowable particle size range. The principle of the particle generating device chosen was that of the LaMer generator, in which a liquid is first vaporized, mixed with the carrier gas, and then condensed under carefully controlled conditions. Preliminary results of studies on the effect of various apparatus parameters on the particle median diameter are given.

  5. Nonlinear Estimation and Control of Particle Trajectories in the Ocean

    DTIC Science & Technology

    2008-09-30

    deployment strategy. This is being accomplished through the use of data assimilation methods for ocean circulation models and the study of extending the assimilation formulation to an optimal control problem.

  6. Nonlinear Estimation and Control of Particle Trajectories in the Ocean

    DTIC Science & Technology

    2007-09-30

    deployment strategy. This is being accomplished through the use of data assimilation methods for ocean circulation models and the study of extending the assimilation formulation to an optimal control problem.

  7. Nonlinear Estimation and Control of Particle Trajectories in the Ocean

    DTIC Science & Technology

    2009-01-01

    deployment strategy. This is being accomplished through the use of data assimilation methods for ocean circulation models and the study of extending the assimilation formulation to an optimal control problem.

  8. 40 CFR 63.9323 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 15 2014-07-01 2014-07-01 false How do I determine the add-on control... determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control device emission destruction...

  9. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... Limitations § 63.3166 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control...

  10. 40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the add-on control... Requirements § 63.4362 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control...

  11. 40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the add-on control... Pollutants: Surface Coating of Metal Cans Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.3545 How do I determine the add-on control device emission destruction or removal...

  12. 40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... § 63.4362 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control...

  13. 40 CFR 63.9323 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 14 2011-07-01 2011-07-01 false How do I determine the add-on control... determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control device emission destruction...

  14. 40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the add-on control... Pollutants: Surface Coating of Metal Cans Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.3545 How do I determine the add-on control device emission destruction or removal...

  15. 40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the add-on control... Requirements § 63.4362 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control...

  16. 40 CFR 63.9323 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 15 2012-07-01 2012-07-01 false How do I determine the add-on control... determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control device emission destruction...

  17. 40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the add-on control... Pollutants: Surface Coating of Metal Cans Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.3545 How do I determine the add-on control device emission destruction or removal...

  18. 40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the add-on control... Requirements § 63.4362 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on control...

  19. 40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... Coating of Metal Cans Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.3545 How do I determine the add-on control device emission destruction or removal efficiency? You must...

  20. 40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... Coating of Wood Building Products Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the add-on control device emission destruction or removal...

  1. 40 CFR 63.4166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... Coating of Large Appliances Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4166 How do I determine the add-on control device emission destruction or removal efficiency? (a)...

  2. 40 CFR 63.4965 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 12 2011-07-01 2009-07-01 true How do I determine the add-on control... Coating of Metal Furniture Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4965 How do I determine the add-on control device emission destruction or removal efficiency? You...

  3. Coherent control of interacting particles using dynamical and Aharonov-Bohm phases.

    PubMed

    Creffield, C E; Platero, G

    2010-08-20

    A powerful method of manipulating the dynamics of quantum coherent particles is to control the phase of their tunneling. We consider a system of two electrons hopping on a quasi-one-dimensional lattice in the presence of a uniform magnetic field and study the effect of adding a time-periodic driving potential. We show that the dynamical phases produced by the driving can combine with the Aharonov-Bohm phases to give precise control of the localization and dynamics of the particles, even in the presence of strong particle interactions.

  4. Size- and shape-controlled synthesis and catalytic performance of iron-aluminum mixed oxide nanoparticles for NOX and SO₂ removal with hydrogen peroxide.

    PubMed

    Ding, Jie; Zhong, Qin; Zhang, Shule; Cai, Wei

    2015-01-01

    A novel, simple, reproducible and low-cost strategy is introduced for the size- and shape-controlled synthesis of iron-aluminum mixed oxide nanoparticles (NIAO(x/y)). The as-synthesized NIAO(x/y) catalyze decomposition of H2O2 yielding highly reactive hydroxyl radicals (OH) for NOX and SO2 removal. 100% SO2 removal is achieved. NIAO(x/y) with Fe/Al molar ratio of 7/3 (NIAO(7/3)) shows the highest NOX removal of nearly 80% at >170°C, whereas much lower NOX removal (<63%) is obtained for NIAO(3/7). The melting of aluminum oxides in NIAO(7/3) promotes the formation of lamellar products, thus improving the specific surface areas and mesoporous distribution, benefiting the production of OH radicals. Furthermore, the NIAO(7/3) leads to the minor increase of points of zero charges (PZC), apparent enhancement of FeOH content and high oxidizing ability of Fe(III), further improving the production of OH radicals. However, the NIAO(3/7) results in the formation of aluminum surface-enriched spherical particles, thus decreasing the surface atomic ratio of iron oxides, decreasing OH radical production. More importantly, the generation of FeOAl causes the decline of active sites. Finally, the catalytic decomposition of H2O2 on NIAO(x/y) is proposed. And the well catalytic stability of NIAO(7/3) is obtained for evaluation of 30 h.

  5. Steric stabilization of nonaqueous silicon slips. I - Control of particle agglomeration and packing. II - Pressure casting of powder compacts

    NASA Technical Reports Server (NTRS)

    Kerkar, Awdhoot V.; Henderson, Robert J. M.; Feke, Donald L.

    1990-01-01

    The application of steric stabilization to control particle agglomeration and packing of silicon powder in benzene and trichloroethylene is reported. The results provide useful guidelines for controlling unfavorable particle-particle interactions during nonaqueous processing of silicon-based ceramic materials. The application of steric stabilization to the control and improvement of green processing of nonaqueous silicon slips in pressure consolidation is also demonstrated.

  6. Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

    NASA Technical Reports Server (NTRS)

    Croley, D. R.; Garrett, H. B.; Murphy, G. B.; Garrard,T. L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU'S. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU'S, very dose to the 243 observed SEU'S. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU

  7. Behavior of total phosphorus removal in an intelligent controlled sequencing batch biofilm reactor for municipal wastewater treatment.

    PubMed

    Cai, Wei; Zhang, Baogang; Jin, Yunxiao; Lei, Zhongfang; Feng, Chuanping; Ding, Dahu; Hu, Weiwu; Chen, Nan; Suemura, Takashi

    2013-03-01

    The behavior of total phosphorus removal was investigated in present study in sequencing batch biofilm reactor (SBBR) controlled by an intelligent control system (ICS) with less energy consumption for municipal wastewater treatment. Stable total phosphorus (TP) removal efficiency of 93.9 ± 2.2% was achieved in comparison to that of 93.3 ± 2.5% in a conventional timer control system (TCS-SBBR). Significant anaerobic phosphorus release was not observed in ICS-SBBR, which was unlike the conventional TCS-SBBR. Moreover, lower accumulations/transformations of polyhydroxyalkanoates (PHAs) and higher transformation of glycogen occurred in the ICS-SBBR, indicating that PHAs was the main energy source while glycogen played a supporting role when PHAs were inadequate, which was different from the traditional mechanism of biological phosphorus removal in TCS-SBBR. The possible biochemical metabolism of phosphorus removal in ICS-SBBR was also elucidated.

  8. Mercury removals by existing pollutants control devices of four coal-fired power plants in China.

    PubMed

    Wang, Juan; Wang, Wenhua; Xu, Wei; Wang, Xiaohao; Zhao, Song

    2011-01-01

    The mercury removals by existing pollution control devices and the mass balances of mercury in four coal-fired power plants of China were carried out based on a measurement method with the aluminum matrix sorbent. All the plants are equipped with a cold-side electrostatic precipitator (ESP) and a wet flue gas desulfurization (FGD) in series. During the course of coal stream, the samples, such as coal, bottom ash, fly ash, gypsum and flue gas, were collected. The Hg concentrations in coals were measured by CVAAS after appropriate preparation and acid digestion. Other solid samples were measured by the RA-915+ Zeeman Mercury Spectrometer. The vapor phase Hg was collected by a sorbent trap from flue gas and then measured using CVAAS followed by acid leaching. The mercury mass balances were estimated in this study were 91.6%, 77.1%, 118% and 85.8% for the four power plants, respectively. The total Hg concentrations in the stack gas were ranged from 1.56-5.95 microg/m3. The relative distribution of Hg in bottom ash, ESP, WFGD and stack discharged were ranged between 0.110%-2.50%, 2.17%-23.4%, 2.21%-87.1%, and 21.8%-72.7%, respectively. The distribution profiles were varied with the coal type and the operation conditions. The Hg in flue gas could be removed by ESP and FGD systems with an average removal efficiency of 51.8%. The calculated average emission factor was 0.066 g/ton and much lower than the results obtained ten years ago.

  9. Monodisperse, Uniformly-Shaped Particles for Controlled Respiratory Vaccine Delivery

    NASA Astrophysics Data System (ADS)

    Fromen, Catherine Ann

    The majority of the world's most infectious diseases occur at the air-tissue interface called the mucosa, including HIV/AIDS, tuberculosis, measles, and bacterial or viral gut and respiratory infections. Despite this, vaccines have generally been developed for the systemic immune system and fail to provide protection at the mucosal site. Vaccine delivery directly to the lung mucosa could provide superior lung protection for many infectious diseases, such as TB or influenza, as well as systemic and therapeutic vaccines for diseases such as Dengue fever, asthma, or cancer. Specifically, precision engineered biomaterials are believed to offer tremendous opportunities for a new generation of vaccines. The goal of this approach is to leverage naturally occurring processes of the immune system to produce memory responses capable of rapidly destroy virulent pathogens without harmful exposure. Considerable knowledge of biomaterial properties and their interaction with the immune system of the lung is required for successful translation. The overall goal of this work was to fabricate and characterize nano- and microparticles using the Particle Replication In Non-wetting Templates (PRINT) fabrication technique and optimize them as pulmonary vaccine carriers. (Abstract shortened by ProQuest.).

  10. Mechanism insights into enhanced trichloroethylene removal using xanthan gum-modified microscale zero-valent iron particles.

    PubMed

    Xin, Jia; Han, Jun; Zheng, Xilai; Shao, Haibing; Kolditz, Olaf

    2015-03-01

    This report focuses on the enhancement in trichloroethylene (TCE) removal from contaminated groundwater using xanthan gum (XG)-modified, microscale, zero-valent iron (mZVI). Compared with bare mZVI, XG-coated mZVI increased the TCE removal efficiency by 30.37% over a 480-h experimental period. Because the TCE removal is attributed to both sorption and reduction processes, the contributions from sorption and reduction were separately investigated to determine the mechanism of XG on TCE removal using mZVI. The results showed that the TCE sorption capacity of mZVI was lower in the presence of XG, whereas the TCE reduction capacity was significantly increased. The FTIR spectra confirmed that XG, which is rich in hydrophilic functional groups, was adsorbed onto the iron surface through intermolecular hydrogen bonds, which competitively repelled the sorption and mass transfer of TCE toward reactive sites. The variations in the pH, Eh, and Fe(2+) concentration as functions of the reaction time were recorded and indicated that XG buffered the solution pH, inhibited surface passivation, and promoted TCE reduction by mZVI. Overall, the XG-modified mZVI was considered to be potentially effective for the in-situ remediation of TCE contaminated groundwater due to its high stability and dechlorination reactivity.

  11. Removal of extrinsic stain using a tartar control whitening dentifrice: a randomized clinical trial.

    PubMed

    Gerlach, R W; White, D J

    2001-01-01

    A nine-week, double blind clinical trial was conducted to evaluate the effectiveness of a novel tartar control whitening dentifrice with a silica-based abrasive system on induced dental stain. The study model involved three weeks of stain induction followed by six weeks of unsupervised brushing to assess efficacy. To induce stain, 222 healthy adult volunteers received a dental prophylaxis, and then began a limited brushing regimen supplemented by three-times daily rinsing with tea and once daily rinsing with 15 ml of 0.12% chlorhexidine. This regimen was suspended, and 187 subjects with tooth stain were entered into a six-week clinical trial where they were randomized to either a silica-based tartar control whitening dentifrice or a marketed regular dentifrice control, balancing for stain levels and smoking status. At baseline, three and six weeks, stain area and stain intensity were measured on the 8 anterior teeth using the Lobene Index. After six weeks' use, composite Lobene means were 35% lower for the whitening dentifrice compared to the regular control. In addition to the overall reductions, there were statistically significant reductions in stain area (p < 0.015) and stain intensity (p < 0.01) at both three and six weeks. The tartar control whitening dentifrice was effective in removing stain on the gingival margins and elsewhere on the body of the tooth. Safety profiles for the two test dentifrices were generally similar. After three and six weeks' use, the tartar control whitening dentifrice reduced chlorhexidine and tea stain compared to the marketed control.

  12. pH-dependent control of particle motion through surface interactions with patterned polymer brush surfaces.

    PubMed

    Dunderdale, Gary; Howse, Jonathan; Fairclough, Patrick

    2012-09-11

    In this Article, we show that inclined silicon surfaces patterned with poly(methacrylic acid) brushes are able to control the position and movement of 20 μm silica particles, which are propelled across the patterned surface by sedimentation forces. Three different types of behavior were observed depending on the angle between the direction in which a particle sedimented and the orientation of the polymer-brush silicon interface. At small angles, particles were found to sediment to the brush interface and then sediment following the direction of the brush interface. At larger angles, particles sedimented to the interface and then followed the direction of the brush interface, but then after a certain distance changed direction to pass over the interface. At the largest angles where the brush interface was approximately perpendicular to the motion of the particle, particles were found to travel over the interface unperturbed. This behavior was also found to be pH dependent, allowing the formation of pH responsive "gates", which allow particles to pass at low pH but not at high pH. It was also found that if patterned polymer brush surfaces were oriented in the correct way, they were able to control the number of particles present at specific locations.

  13. Facile preparation of acid-resistant magnetite particles for removal of Sb(Ⅲ) from strong acidic solution

    PubMed Central

    Wang, Dong; Guan, Kaiwen; Bai, Zhiping; Liu, Fuqiang

    2016-01-01

    Abstract A new facile coating strategy based on the hydrophobicity of methyl groups was developed to prevent nano-sized magnetite particles from strong acid corrosion. In this method, three steps of hydrolysis led to three layers of protection shell coating Fe3O4 nanoparticles. Filled with hydrophobic methyl groups, the middle layer mainly prevented the magnetic core from strong acid corrosion. These magnetite particles managed to resist 1 M HCl solution and 2.5 M H2SO4 solution. The acid resistant ability was higher than those reported previously. After further modification with amino-methylene-phosphonic groups, these magnetite particles successfully adsorbed Sb(III) in strong acid solution. This new strategy can also be applied to protect other materials from strong acid corrosion. PMID:27877860

  14. Integration of a nonmetallic electrostatic precipitator and a wet scrubber for improved removal of particles and corrosive gas cleaning in semiconductor manufacturing industries.

    PubMed

    Kim, Hak-Joon; Han, Bangwoo; Kim, Yong-Jin; Yoa, Seok-Jun; Oda, Tetsuji

    2012-08-01

    To remove particles in corrosive gases generated by semiconductor industries, we have developed a novel non-metallic, two-stage electrostatic precipitator (ESP). Carbon brush electrodes and grounded carbon fiber-reinforced polymer (CFRP) form the ionization stage, and polyvinyl chloride collection plates are used in the collection stage of the ESP The collection performance of the ESP downstream of a wet scrubber was evaluated with KC1, silica, and mist particles (0.01-10 pm), changing design and operation parameters such as the ESP length, voltage, and flow rate. A long-term and regeneration performance (12-hr) test was conducted at the maximum operation conditions of the scrubber and ESP and the performance was then demonstrated for 1 month with exhaust gases from wet scrubbers at the rooftop of a semiconductor manufacturing plant in Korea. The results showed that the electrical and collection performance of the ESP (16 channels, 400x400 mm2) was maintained with different grounded plate materials (stainless steel and CFRP) and different lengths of the ionization stage. The collection efficiency of the ESP at high air velocity was enhanced with increases in applied voltages and collection plate lengths. The ESP (16 channels with 100 mm length, 400x400 mm2x540 mm with a 10-mm gap) removed more than 90% of silica and mistparticles with 10 and 12 kV applied to the ESPat the air velocity of 2 m/s and liquid-to-gas ratio of 3.6 L/m3. Decreased performance after 13 hours ofcontinuous operation was recovered to the initial performance level by 5 min of water washing. Moreover during the 1-month operation at the demonstration site, the ESP showed average collection efficiencies of 97% based on particle number and 92% based on total particle mass, which were achieved with a much smaller specific corona power of 0.28 W/m3/hr compared with conventional ESPs.

  15. Auxiliary particle filter-model predictive control of the vacuum arc remelting process

    NASA Astrophysics Data System (ADS)

    Lopez, F.; Beaman, J.; Williamson, R.

    2016-07-01

    Solidification control is required for the suppression of segregation defects in vacuum arc remelting of superalloys. In recent years, process controllers for the VAR process have been proposed based on linear models, which are known to be inaccurate in highly-dynamic conditions, e.g. start-up, hot-top and melt rate perturbations. A novel controller is proposed using auxiliary particle filter-model predictive control based on a nonlinear stochastic model. The auxiliary particle filter approximates the probability of the state, which is fed to a model predictive controller that returns an optimal control signal. For simplicity, the estimation and control problems are solved using Sequential Monte Carlo (SMC) methods. The validity of this approach is verified for a 430 mm (17 in) diameter Alloy 718 electrode melted into a 510 mm (20 in) diameter ingot. Simulation shows a more accurate and smoother performance than the one obtained with an earlier version of the controller.

  16. Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts

    SciTech Connect

    Woodson, Jesse D.; Joens, Matthew S.; Sinson, Andrew B.; Gilkerson, Jonathan; Salome, Patrice A.; Weigel, Detlef; Fitzpatrick, James A.; Chory, Joanne

    2015-10-23

    Energy production by chloroplasts and mitochondria causes constant oxidative damage. A functioning photosynthetic cell requires quality-control mechanisms to turn over and degrade chloroplasts damaged by reactive oxygen species (ROS). Here in this study, we generated a conditionally lethal Arabidopsis mutant that accumulated excess protoporphyrin IX in the chloroplast and produced singlet oxygen. Damaged chloroplasts were subsequently ubiquitinated and selectively degraded. A genetic screen identified the plant U-box 4 (PUB4) E3 ubiquitin ligase as being necessary for this process. pub4-6 mutants had defects in stress adaptation and longevity. As a result, we have identified a signal that leads to the targeted removal of ROS-overproducing chloroplasts.

  17. Controlled removal of amorphous Se capping layer from a topological insulator

    SciTech Connect

    Virwani, Kumar; Pushp, Aakash Topuria, Teya; Delenia, Eugene; Rice, Philip; Kellock, Andrew; Parkin, Stuart; Harrison, Sara E.; Collins-McIntyre, Liam; Hesjedal, Thorsten; Harris, James

    2014-12-15

    We report on the controlled removal of an amorphous Se capping layer from Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} topological insulators. We show that the Se coalesces into micron-sized islands before desorbing from the surface at a temperature of ∼150 °C. In situ Auger Electron Spectroscopy reveals that Se replaces a significant fraction of the Te near the top surface of the Bi{sub 2}Te{sub 3}. Rutherford Backscattering Spectrometry and Transmission Electron Microscopy show that after heating, Se has been incorporated in the Bi{sub 2}Te{sub 3} lattice down to ∼7 nm from its top surface while remaining iso-structural.

  18. Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts

    DOE PAGES

    Woodson, Jesse D.; Joens, Matthew S.; Sinson, Andrew B.; ...

    2015-10-23

    Energy production by chloroplasts and mitochondria causes constant oxidative damage. A functioning photosynthetic cell requires quality-control mechanisms to turn over and degrade chloroplasts damaged by reactive oxygen species (ROS). Here in this study, we generated a conditionally lethal Arabidopsis mutant that accumulated excess protoporphyrin IX in the chloroplast and produced singlet oxygen. Damaged chloroplasts were subsequently ubiquitinated and selectively degraded. A genetic screen identified the plant U-box 4 (PUB4) E3 ubiquitin ligase as being necessary for this process. pub4-6 mutants had defects in stress adaptation and longevity. As a result, we have identified a signal that leads to the targetedmore » removal of ROS-overproducing chloroplasts.« less

  19. Including Life Cycle Assessment for decision-making in controlling wastewater nutrient removal systems.

    PubMed

    Corominas, Lluís; Larsen, Henrik F; Flores-Alsina, Xavier; Vanrolleghem, Peter A

    2013-10-15

    This paper focuses on the use of Life Cycle Assessment (LCA) to evaluate the performance of seventeen control strategies in wastewater treatment plants (WWTPs). It tackles the importance of using site-specific factors for nutrient enrichment when decision-makers have to select best operating strategies. Therefore, the LCA evaluation is repeated for three different scenarios depending on the limitation of nitrogen (N), phosphorus (P), or both, when evaluating the nutrient enrichment impact in water bodies. The LCA results indicate that for treated effluent discharged into N-deficient aquatic systems (e.g. open coastal areas) the most eco-friendly strategies differ from the ones dealing with discharging into P-deficient (e.g. lakes and rivers) and N&P-deficient systems (e.g. coastal zones). More particularly, the results suggest that strategies that promote increased nutrient removal and/or energy savings present an environmental benefit for N&P and P-deficient systems. This is not the case when addressing N-deficient systems for which the use of chemicals (even for improving N removal efficiencies) is not always beneficial for the environment. A sensitivity analysis on using weighting of the impact categories is conducted to assess how value choices (policy decisions) may affect the management of WWTPs. For the scenarios with only N-limitation, the LCA-based ranking of the control strategies is sensitive to the choice of weighting factors, whereas this is not the case for N&P or P-deficient aquatic systems.

  20. PARTICLE REMOVAL RATES BY THE MUD SHRIMP UPOGEBIA PUGETTENSIS, ITS BURROW, AND A COMMENSAL CLAM: EFFECTS ON ESTUARINE PHYTOPLANKTON ABUNDANCE

    EPA Science Inventory

    The burrowing shrimp Upogebia pugettensis is an abundant intertidal inhabitant of Pacific Northwest bays and estuaries where it lives commensally with the bivalve Cryptomya californica. Suspension-feeding activities by the shrimp and by its commensal clam, as well as particle se...

  1. Method of removing SO.sub.2, NO.sub.X and particles from gas mixtures using streamer corona

    DOEpatents

    Mizuno, Akira; Clements, Judson S.

    1987-01-01

    A method for converting sulfur dioxide and/or nitrogen oxide gases to acid mist and or particle aerosols is disclosed in which the gases are passed through a streamer corona discharge zone having electrodes of a wire-cylinder or wire-plate geometry.

  2. Laser trapping in anisotropic fluids and polarization-controlled particle dynamics.

    PubMed

    Smalyukh, Ivan I; Kachynski, Aliaksandr V; Kuzmin, Andrey N; Prasad, Paras N

    2006-11-28

    Anisotropic fluids are widespread, ranging from liquid crystals used in displays to ordered states of a biological cell interior. Optical trapping is potentially a powerful technique in the fundamental studies and applications of anisotropic fluids. We demonstrate that laser beams in these fluids can generate anisotropic optical trapping forces, even for particles larger than the trapping beam wavelength. Immersed colloidal particles modify the fluid's ordered molecular structures and locally distort its optic axis. This distortion produces a refractive index "corona" around the particles that depends on their surface characteristics. The laser beam can trap such particles not only at their center but also at the high-index corona. Trapping forces in the beam's lateral plane mimic the corona and are polarization-controlled. This control allows the optical forces to be reversed and cause the particle to follow a prescribed trajectory. Anisotropic particle dynamics in the trap varies with laser power because of the anisotropy of both viscous drag and trapping forces. Using thermotropic liquid crystals and biological materials, we show that these phenomena are quite general for all anisotropic fluids and impinge broadly on their quantitative studies using laser tweezers. Potential applications include modeling thermodynamic systems with anisotropic polarization-controlled potential wells, producing optically tunable photonic crystals, and fabricating light-controlled nano- and micropumps.

  3. Magnetic removal of dyes from aqueous solution using multi-walled carbon nanotubes filled with Fe2O3 particles.

    PubMed

    Qu, Song; Huang, Fei; Yu, Shaoning; Chen, Gang; Kong, Jilie

    2008-12-30

    The Fe2O3 nanoparticles have been introduced into the multi-walled carbon nanotubes (MWCNTs) via wet chemical method. The resulting products are characterized by TEM, EDX, XRD and VSM. The magnetic MWCNTs have been employed as adsorbent for the magnetic separation of dye contaminants from water. The adsorption test of dyes (Methylene Blue and Neutral Red) demonstrates that it only takes 60min to attain equilibrium and the adsorption capacities for Methylene Blue and Neutral Red in the concentration range studied are 42.3 and 77.5mg/g, respectively. The magnetic MWCNTs can be easily manipulated in magnetic field for desired separation, leading to the removal of dyes from polluted water. The integration of MWCNTs with Fe2O3 nanoparticles has great potential application to remove organic dyes from polluted water.

  4. Morphology Control of FeCo Alloy Particles Synthesized by Polyol Process

    SciTech Connect

    Kodama, D.; Sato, Y.; Tohji, K.; Jeyadevan, B.; Shinoda, K.; Sato, K.

    2007-03-20

    FeCo alloy is a soft magnetic material that possesses the highest saturation magnetization of 2.4 T and crystallizes in bcc structure as in the case of {alpha}-Fe. However, the particles synthesized were highly agglomerated. Thus, in this paper, an attempt was made to control the morphology of the particles using different types and concentrations of surfactants such as oleic acid, oleyl amine, polyvinylpyrrolidone (PVP), etc., during the synthesis of the particles. Though all the surfactant experimented partially prevented the agglomeration, products had larger size distribution except for PVP, which provided nearly monodispersed particles. Furthermore, the FeCo particles synthesized in the presence of PVP were either cubic or nearly spherical depending on the concentration of Fe.

  5. Morphology Control of FeCo Alloy Particles Synthesized by Polyol Process

    NASA Astrophysics Data System (ADS)

    Kodama, D.; Shinoda, K.; Sato, K.; Sato, Y.; Tohji, K.; Jeyadevan, B.

    2007-03-01

    FeCo alloy is a soft magnetic material that possesses the highest saturation magnetization of 2.4 T and crystallizes in bcc structure as in the case of α-Fe. However, the particles synthesized were highly agglomerated. Thus, in this paper, an attempt was made to control the morphology of the particles using different types and concentrations of surfactants such as oleic acid, oleyl amine, polyvinylpyrrolidone (PVP), etc., during the synthesis of the particles. Though all the surfactant experimented partially prevented the agglomeration, products had larger size distribution except for PVP, which provided nearly monodispersed particles. Furthermore, the FeCo particles synthesized in the presence of PVP were either cubic or nearly spherical depending on the concentration of Fe.

  6. Analytical optimal controls for the state constrained addition and removal of cryoprotective agents

    PubMed Central

    Chicone, Carmen C.; Critser, John K.

    2014-01-01

    Cryobiology is a field with enormous scientific, financial and even cultural impact. Successful cryopreservation of cells and tissues depends on the equilibration of these materials with high concentrations of permeating chemicals (CPAs) such as glycerol or 1,2 propylene glycol. Because cells and tissues are exposed to highly anisosmotic conditions, the resulting gradients cause large volume fluctuations that have been shown to damage cells and tissues. On the other hand, there is evidence that toxicity to these high levels of chemicals is time dependent, and therefore it is ideal to minimize exposure time as well. Because solute and solvent flux is governed by a system of ordinary differential equations, CPA addition and removal from cells is an ideal context for the application of optimal control theory. Recently, we presented a mathematical synthesis of the optimal controls for the ODE system commonly used in cryobiology in the absence of state constraints and showed that controls defined by this synthesis were optimal. Here we define the appropriate model, analytically extend the previous theory to one encompassing state constraints, and as an example apply this to the critical and clinically important cell type of human oocytes, where current methodologies are either difficult to implement or have very limited success rates. We show that an enormous increase in equilibration efficiency can be achieved under the new protocols when compared to classic protocols, potentially allowing a greatly increased survival rate for human oocytes, and pointing to a direction for the cryopreservation of many other cell types. PMID:22527943

  7. Sensori-motor integration during stance: time adaptation of control mechanisms on adding or removing vision.

    PubMed

    Sozzi, Stefania; Monti, Alberto; De Nunzio, Alessandro Marco; Do, Manh-Cuong; Schieppati, Marco

    2011-04-01

    Sudden addition or removal of visual information can be particularly critical to balance control. The promptness of adaptation of stance control mechanisms is quantified by the latency at which body oscillation and postural muscle activity vary after a shift in visual condition. In the present study, volunteers stood on a force platform with feet parallel or in tandem. Shifts in visual condition were produced by electronic spectacles. Ground reaction force (center of foot pressure, CoP) and EMG of leg postural muscles were acquired, and latency of CoP and EMG changes estimated by t-tests on the averaged traces. Time-to-reach steady-state was estimated by means of an exponential model. On allowing or occluding vision, decrements and increments in CoP position and oscillation occurred within about 2s. These were preceded by changes in muscle activity, regardless of visual-shift direction, foot position or front or rear leg in tandem. These time intervals were longer than simple reaction-time responses. The time course of recovery to steady-state was about 3s, shorter for oscillation than position. The capacity of modifying balance control at very short intervals both during quiet standing and under more critical balance conditions speaks in favor of a necessary coupling between vision, postural reference, and postural muscle activity, and of the swiftness of this sensory reweighing process.

  8. Coyote removal, understory cover, and survival of white-tailed deer neonates: Coyote Control and Fawn Survival

    SciTech Connect

    Kilgo, John C.; Vukovich, Mark; Ray, H. Scott; Shaw, Christopher E.; Ruth, Charles

    2014-09-01

    Predation by coyotes (Canis latrans) on white-tailed deer (Odocoileus virginianus) neonates has led to reduced recruitment in many deer populations in southeastern North America. This low recruitment combined with liberal antlerless deer harvest has resulted in declines in some deer populations, and consequently, increased interest in coyote population control. We investigated whether neonate survival increased after coyote removal, whether coyote predation on neonates was additive to other mortality sources, and whether understory vegetation density affected neonate survival. We monitored neonate survival for 4 years prior to (2006–2009) and 3 years during (2010–2012) intensive coyote removal on 3 32-km2 units on the United States Department of Energy’s Savannah River Site, South Carolina. We removed 474 coyotes (1.63 coyotes/km2 per unit per year), reducing coyote abundance by 78% from pre-removal levels. The best model (wi = 0.927) describing survival probability among 216 radio-collared neonates included a within-year quadratic time trend variable, date of birth, removal treatment, and a varying removal year effect. Under this model, survival differed between pre-treatment and removal periods and it differed among years during the removal period, being >100% greater than pre-treatment survival (0.228) during the first removal year (0.513), similar to pre-treatment survival during the second removal year (0.202), and intermediate during the third removal year (0.431). Despite an initial increase, the overall effect of coyote removal on neonate survival was modest. Mortality rate attributable to coyote predation was lowest during the first removal year (0.357) when survival was greatest, but the mortality rate from all other causes did not differ between the pretreatment period and any year during removals, indicating that coyote predation acted as an additive source of mortality. Survival probability was not related to

  9. Controlling active self-assembly through broken particle-shape symmetry.

    PubMed

    Wensink, H H; Kantsler, V; Goldstein, R E; Dunkel, J

    2014-01-01

    Many structural properties of conventional passive materials are known to arise from the symmetries of their microscopic constituents. By contrast, it is largely unclear how the interplay between particle shape and self-propulsion controls the meso- and macroscale behavior of active matter. Here we use large-scale simulations of homo- and heterogeneous self-propelled particle systems to identify generic effects of broken particle-shape symmetry on collective motion. We find that even small violations of fore-aft symmetry lead to fundamentally different collective behaviors, which may facilitate demixing of differently shaped species as well as the spontaneous formation of stable microrotors. These results suggest that variation of particle shape yields robust physical mechanisms to control self-assembly of active matter, with possibly profound implications for biology and materials design.

  10. Size controllable synthesis of ultrafine spherical gold particles and their simulation of plasmonic and SERS behaviors

    NASA Astrophysics Data System (ADS)

    Yi, Zao; Xu, Xibin; Luo, Jiangshan; Li, Xibo; Yi, Yong; Jiang, Xiaodong; Yi, Yougen; Tang, Yongjian

    2014-04-01

    A simple and reproducible way was explored to synthesize quasi-spherical gold particles with different size distributions in water by rapidly adding a mixture solution of HAuCl4, sodium citrate, and a trace amount of silver nitrate. By careful tuning of the reaction parameters, mono-disperse gold particles with the diameter of 5-220 nm can be obtained controllably. The particle size of 130 nm for the particles film showed the highest SERS activity with the 632.8 nm excitation. The theoretical calculations of the UV-vis extinction spectra can be directly compared with experiments by using the discrete-dipole approximation (DDA). Control of nanostructure shape allows optimization of plasmon resonance for molecular detection and spectroscopy.

  11. Seep-carbonate lamination controlled by cyclic particle flux

    NASA Astrophysics Data System (ADS)

    Himmler, Tobias; Bayon, Germain; Wangner, David; Enzmann, Frieder; Peckmann, Jörn; Bohrmann, Gerhard

    2016-11-01

    Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U–Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes.

  12. Seep-carbonate lamination controlled by cyclic particle flux

    PubMed Central

    Himmler, Tobias; Bayon, Germain; Wangner, David; Enzmann, Frieder; Peckmann, Jörn; Bohrmann, Gerhard

    2016-01-01

    Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U–Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes. PMID:27876764

  13. Seep-carbonate lamination controlled by cyclic particle flux.

    PubMed

    Himmler, Tobias; Bayon, Germain; Wangner, David; Enzmann, Frieder; Peckmann, Jörn; Bohrmann, Gerhard

    2016-11-23

    Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U-Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes.

  14. Synthesis and characterization of chitosan/Mg-Al layered double hydroxide composite for the removal of oil particles from oil-in-water emulsion.

    PubMed

    Elanchezhiyan, S Sd; Meenakshi, Sankaran

    2017-01-23

    The recovery of oil from oil-in-water emulsion has been investigated using chitosan/magnesium-aluminium layered double hydroxide hybrid composite (CS-LDHCs) by a single co-precipitation method. Resulting better adsorption efficiency of CS-LDHCs could be observed, indicating the synthesized material was effective to adsorb oil particles from oil-in-water emulsion at acidic pH (pH 3.0) than as-prepared LDH and raw chitosan. The enhancement of adsorption properties by CS-LDHCs material were attributed to the high content of LDH in chitosan, which makes the material more effective towards immobilization of oily particles. Batch experiment study has been elucidated by varying different physicochemical parameters such as time, pH, dose, initial oil concentration and temperature. The as-synthesized CS-LDHCs was characterized by various spectro analytical techniques viz., FTIR, SEM with EDAX, XRD, TGA and DSC analysis. To find out the best fit for the sorption process, the obtained adsorption equilibrium data was explained with Freundlich, Langmuir, Dubinin-Radushkevich and Tempkin isotherm models. The mechanism of adsorption process was demonstrated by calculating ΔG°, ΔH° and ΔS° values from thermodynamic parameters in order to understand the nature of sorption process. The schematic representation of oil removal using CS-LDHCs was explored in detail. This work provides an apparent proposal for the growth of oil removal technology.

  15. Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles.

    PubMed

    Zhang, Yulong; Dong, Rui; Park, Yujin; Bohner, Marc; Zhang, Xinli; Ting, Kang; Soo, Chia; Wu, Benjamin M

    2016-09-10

    NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein's bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research.

  16. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false How do I determine the add-on control... Emission Limitations § 63.3166 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on...

  17. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true How do I determine the add-on control... Emission Limitations § 63.3166 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on...

  18. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 13 2014-07-01 2014-07-01 false How do I determine the add-on control... Emission Limitations § 63.3166 How do I determine the add-on control device emission destruction or removal efficiency? You must use the procedures and test methods in this section to determine the add-on...

  19. Characterization, Exposure Measurement and Control for Nanoscale Particles in Workplaces and on the Road

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Pui, David Y. H.

    2011-07-01

    The amount of engineered nanoparticles is increasing at a rapid rate and more concerns are being raised about the occupational health and safety of nanoparticles in the workplace, and implications of nanotechnology on the environment and living systems. At the same time, diesel engine emissions are one of the serious air pollution sources in urban area. Ultrafine particles on the road can result in harmful effects on the health of drivers and passengers. Research on characterization, exposure measurement and control is needed to address the environmental, health and safety issues of nanoscale particles. We present results of our studies on airborne particles in workplaces and on the road.

  20. Shape control of self-organized porous silica submicron particles and their strength evaluation

    NASA Astrophysics Data System (ADS)

    Kiyohara, Keita; Inoue, Keita; Inoue, Shozo; Namazu, Takahiro

    2016-06-01

    In this paper, precise control of the shape, size, and porosity of porous silica submicron particles and their strength evaluation are described. Self-organization phenomenon of silica nanopowders and submicron polystyrene latex (PSL) balls in an atomized mist is used for the fabrication of the particles. When temperatures of lower- and upper-zone heaters are 100 and 600 °C, and N2 gas flow rate is 0.4 l/min, spherical particles are produced. When PSL concentration increases, the number of pores increases. Particles with uniformly-arranged pores are produced at the PSL concentration of around 3 wt %. By using the PSL balls of different diameters, porous silica particles including different size pores are made. Also, compressive fracture test is conducted to check the effect of vacuum annealing on the strength of particles. The annealed particle shows higher fracture force than the unannealed particle, which indicates that the annealing would be effective for improving the mechanical reliability.

  1. Electrohydrodynamic controlled assembly and fracturing of thin colloidal particle films confined at drop interfaces

    NASA Astrophysics Data System (ADS)

    Rozynek, Z.; Dommersnes, P.; Mikkelsen, A.; Michels, L.; Fossum, J. O.

    2014-09-01

    Particles can adsorb strongly at liquid interfaces due to capillary forces, which in practice can confine the particles to the interface. Here we investigate the electrohydrodynamic flow driven packing and deformation of colloidal particle layers confined at the surface of liquid drops. The electrohydrodynamic flow has a stagnation point at the drop equator, leading to assembly of particles in a ribbon shaped film. The flow is entirely controlled by the electric field, and we demonstrate that AC fields can be used to induce hydrodynamic "shaking" of the colloidal particle film. We find that the mechanical properties of the film is highly dependent on the particles: monodisperse polystyrene beads form packed granular monolayers which "liquefies" upon shaking, whereas clay mineral particles form cohesive films that fracture upon shaking. The results are expected to be relevant for understanding the mechanics and rheology of particle stabilized emulsions. Supplementary material in the form of a pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjst/e2014-02231-x

  2. Methotrexate intercalated layered double hydroxides with different particle sizes: structural study and controlled release properties.

    PubMed

    Zhang, Xiao-Qing; Zeng, Mei-Gui; Li, Shu-Ping; Li, Xiao-Dong

    2014-05-01

    To study the influence of particle size on release properties, drug efficacy and other properties, a series of methotrexate intercalated layered double hydroxides (MTX/LDHs) nanohybrids with different particle sizes were synthesized through traditional coprecipitation method, by using the mixture of water and polyethylene glycol (volume ratio is 3:1) as solvent. The relationship between particle size and hydrothermal treatment conditions (i.e., time and temperature) had been systematically investigated, and the results indicate that the particle size can be precisely controlled between 70 and 300 nm. Elemental C/H/N and inductive coupled plasma (ICP) analysis indicated that different hydrothermal treatment almost has no effect on compositions of the nanohybrids. X-ray diffraction (XRD) patterns and fourier transform infrared spectroscopy (FTIR) investigations manifested the successful intercalation of MTX anions. MTX/LDHs particles exhibited hexagonal platelet morphology with round corner, due to the adsorption of MTX anions on positively charged LDHs surface. In addition, the crystallinity of MTX/LDHs increased with the particle diameters and the thermal stability of MTX anions was enhanced by holding together with LDHs layers. The in vitro release showed that bigger particles have much longer release duration, and the bioassay tests indicated that bigger particles are more efficient in the suppression of the tumor cells.

  3. Lotus-like effect for metal filings recovery and particle removal on heated metal surfaces using Leidenfrost water droplets.

    PubMed

    Tan, Cher Lin Clara; Sapiha, Kostantyn; Leong, Yoke Fun Hannah; Choi, Siwon; Anariba, Franklin; Thio, Beng Joo Reginald

    2015-07-21

    A "lotus-like" effect is applied to demonstrate the ability of the Leidenfrost water droplets to recover Cu particles on a heated Al substrate. Cu particles on the heated surface adhere to the rim of the Leidenfrost droplets and eventually coat the droplets' surface to form an aggregation. When Fe filings are added to the Cu particles, the aggregated mixture can then be collected using a strong rare earth magnet (NdFeB) upon evaporation of the water. We also show that the Leidenfrost effect can be effectively utilized to recover both hydrophobic (dust and activated carbon) and hydrophilic (SiO2 and MgO) particles from heated Al surfaces without any topographical modification or surfactant addition. Our results show that hydrophobic and hydrophilic materials can be collected with >92% and >96% effectiveness on grooved and smooth Al surfaces, respectively. Furthermore, we observed no significant differences in the amount of material collected above the Leidenfrost point within the tested temperature range (240 °C vs. 340 °C) as well as when the Al sheet was replaced with a Cu sheet as the substrate. However, we did observe that the Leidenfrost droplets were able to collect a greater amount of material when the working liquid was water than when it was ethanol. Our findings show promise in the development of an effective precious coinage metal filings recovery technology for application in the mint industry, as well as the self-cleaning of metallic and semiconductor surfaces where manual cleaning is not amenable.

  4. Simultaneous removal of cadmium and nitrate in aqueous media by nanoscale zerovalent iron (nZVI) and Au doped nZVI particles.

    PubMed

    Su, Yiming; Adeleye, Adeyemi S; Huang, Yuxiong; Sun, Xiaoya; Dai, Chaomeng; Zhou, Xuefei; Zhang, Yalei; Keller, Arturo A

    2014-10-15

    Nanoscale zerovalent iron (nZVI) has demonstrated high efficacy for treating nitrate or cadmium (Cd) contamination, but its efficiency for simultaneous removal of nitrate and Cd has not been investigated. This study evaluated the reactivity of nZVI to the co-contaminants and by-product formation, employed different catalysts to reduce nitrite yield from nitrate, and examined the transformation of nZVI after reaction. Nitrate reduction resulted in high solution pH, negatively charged surface of nZVI, formation of Fe3O4 (a stable transformation of nZVI), and no release of ionic iron. Increased pH and negative charge contributed to significant increase in Cd(II) removal capacity (from 40 mg/g to 188 mg/g) with nitrate present. In addition, nitrate reduction by nZVI could be catalyzed by Cd(II): while 30% of nitrate was reduced by nZVI within 2 h in the absence of Cd(II), complete nitrate reduction was observed in the presence of 40 mg-Cd/L due to the formation of Cd islands (Cd(0) and CdO) on the nZVI particles. While nitrate was reduced mostly to ammonium when Cd(II) was not present or at Cd(II) concentrations ≥ 40 mg/L, up to 20% of the initial nitrate was reduced to nitrite at Cd(II) concentrations < 40 mg/L. Among nZVI particles doped with 1 wt. % Cu, Ag, or Au, nZVI deposited with 1 wt. % Au reduced nitrite yield to less than 3% of the initial nitrate, while maintaining a high Cd(II) removal capacity.

  5. Space Shuttle reaction control system thruster metal nitrate removal and characterization

    NASA Technical Reports Server (NTRS)

    Saulsberry, R. L.; Mccartney, P. A.

    1993-01-01

    The Space Shuttle hypergolic primary reaction control system (PRCS) thrusters continue to fail-leak or fail-off at a rate of approximately 1.5 per flight, attributed primarily to metal nitrate formation in the nitrogen tetroxide (N2O4) pilot operated valves (POV's). The failures have continued despite ground support equipment (GSE) and subsystem operational improvements. As a result, the Johnson Space Center (JSC) White Sands Test Facility (WSTF) performed a study to characterize the contamination in the N204 valves. This study prompted the development and implementation of a highly successful flushing technique using deionized (DI) water and gaseous nitrogen (GN2) to remove the contamination while minimizing Teflon seat damage. Following flushing a comprehensive acceptance test is performed before the thruster is deemed recovered. Between the time WSTF was certified to process flight thrusters (March 1992) and September 1993, a 68 percent thruster recovery rate was achieved. The contamination flushed from these thrusters was analyzed and has provided insight into the corrosion process, which is reported in this publication. Additionally, the long-term performance of 24 flushed thrusters installed in the WSTF Fleet Leader Shuttle reaction control subsystem (RCS) test articles is being assessed. WSTF continues to flush flight and test article thrusters and compile data to investigate metal nitrate formation characteristics in leaking and nonleaking valves.

  6. The faulty Master Events Controller is removed from STS-99 Endeavour

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Technicians remove a faulty Enhanced Main Events Controller (E- MEC) from Shuttle Endeavour at Launch Pad 39A. The E-MEC became suspect during the Jan. 31 launch countdown and mission STS-99 was delayed when NASA managers decided to replace it. Each Shuttle carries two enhanced master events controllers (E-MECs), which provide relays for onboard flight computers to send signals to arm and fire pyrotechnics that separate the solid rockets and external tank during assent. Both E-MECs are needed for the Shuttle to be cleared for flight. Currently Endeavour and Columbia are the only two orbiters with the E-MECs. Built by Rockwell's Satellite Space Electronics Division, Anaheim, Calif., each unit weighs 65 pounds and is approximately 20 inches long, 13 inches wide and 8 inches tall. Previously, three Shuttle flights have been scrubbed or delayed due to faulty MECs: STS-73, STS-49 and STS-41-D. The next scheduled date for launch of STS-99 is Feb. 11 at 12:30 p.m. EST.

  7. Silica coated magnetic particles using microwave synthesis for removal of dyes from natural water samples: Synthesis, characterization, equilibrium, isotherm and kinetics studies

    NASA Astrophysics Data System (ADS)

    Ahmed, Salwa A.; Soliman, Ezzat M.

    2013-11-01

    Monitoring pollutants in water samples is a challenge to analysts. So, the removal of Napthol blue black (NBB) and Erichrome blue black R (EBBR) from aqueous solutions was investigated using magnetic chelated silica particles. Magnetic solids are widely used in detection and analytical systems because of the performance advantages they offer compared to similar solids that lack magnetic properties. In this context, a fast, simple and clean method for modification of magnetic particles (Fe3O4) with silica gel was developed using microwave technique to introduce silica gel coated magnetic particles (SG-MPs) sorbent. The magnetic sorbent was characterized by the FT-IR, X-ray diffraction (XRD), and scan electron microscope (SEM) analyses. The effects of pH, time, weight of sorbent and initial concentration of dye were evaluated. It was interesting to find from results that SG-MPs exhibits high percentage extraction of the studied dyes (100% for NBB and 98.75% for EBBR) from aqueous solutions. The Freundlich isotherm with r2 = 0.973 and 0.962 and Langmuir isotherms with r2 = 0.993 and 0.988 for NBB and EBBR, respectively were used to describe adsorption equilibrium. Also, adsorption kinetic experiments have been carried out and the data have been well fitted by a pseudo-second-order equation r2 = 1.0 for NBB and 0.999 for EBBR. The prepared sorbent with rapid adsorption rate and separation convenience was applied for removal of NBB and EBBR pollutants from natural water samples with good precision (RSD% = 0.05-0.3%).

  8. Photocatalytic/Magnetic Composite Particles

    NASA Technical Reports Server (NTRS)

    Wu, Chang-Yu; Goswami, Yogi; Garretson, Charles; Andino, Jean; Mazyck, David

    2007-01-01

    Photocatalytic/magnetic composite particles have been invented as improved means of exploiting established methods of photocatalysis for removal of chemical and biological pollutants from air and water. The photocatalytic components of the composite particles are formulated for high levels of photocatalytic activity, while the magnetic components make it possible to control the movements of the particles through the application of magnetic fields. The combination of photocatalytic and magnetic properties can be exploited in designing improved air- and water treatment reactors.

  9. Stable Carbon Fractionation In Size Segregated Aerosol Particles Produced By Controlled Biomass Burning

    NASA Astrophysics Data System (ADS)

    Masalaite, Agne; Garbaras, Andrius; Garbariene, Inga; Ceburnis, Darius; Martuzevicius, Dainius; Puida, Egidijus; Kvietkus, Kestutis; Remeikis, Vidmantas

    2014-05-01

    Biomass burning is the largest source of primary fine fraction carbonaceous particles and the second largest source of trace gases in the global atmosphere with a strong effect not only on the regional scale but also in areas distant from the source . Many studies have often assumed no significant carbon isotope fractionation occurring between black carbon and the original vegetation during combustion. However, other studies suggested that stable carbon isotope ratios of char or BC may not reliably reflect carbon isotopic signatures of the source vegetation. Overall, the apparently conflicting results throughout the literature regarding the observed fractionation suggest that combustion conditions may be responsible for the observed effects. The purpose of the present study was to gather more quantitative information on carbonaceous aerosols produced in controlled biomass burning, thereby having a potential impact on interpreting ambient atmospheric observations. Seven different biomass fuel types were burned under controlled conditions to determine the effect of the biomass type on the emitted particulate matter mass and stable carbon isotope composition of bulk and size segregated particles. Size segregated aerosol particles were collected using the total suspended particle (TSP) sampler and a micro-orifice uniform deposit impactor (MOUDI). The results demonstrated that particle emissions were dominated by the submicron particles in all biomass types. However, significant differences in emissions of submicron particles and their dominant sizes were found between different biomass fuels. The largest negative fractionation was obtained for the wood pellet fuel type while the largest positive isotopic fractionation was observed during the buckwheat shells combustion. The carbon isotope composition of MOUDI samples compared very well with isotope composition of TSP samples indicating consistency of the results. The measurements of the stable carbon isotope ratio in

  10. Benthic biofilm structure controls the deposition-resuspension dynamics of fine clay particles

    NASA Astrophysics Data System (ADS)

    Hunter, W. R.; Roche, K. R.; Drummond, J. D.; Boano, F.; Packman, A. I.; Battin, T. J.

    2015-12-01

    In fluvial ecosystems the alternation of deposition and resuspension of particles represents an important pathway for the downstream translocation of microbes and organic matter. Such particles can originate from algae and microbes, the spontaneous auto-aggregation of organic macromolecules (e.g., "river sown"), terrestrial detritus (traditionally classified as "particulate organic matter"), and erosive mineral and organo-mineral particles. The transport and retention of particles in headwater streams is associated with biofilms, which are surface-attached microbial communities. Whilst biofilm-particle interactions have been studied in bulk, a mechanistic understanding of these processes is lacking. Parallel macroscale/microscale observations are required to unravel the complex feedbacks between biofilm structure, coverage and the dynamics of deposition and resuspension. We used recirculating flume mesocosms to test how changes in biofilm structure affected the deposition and resuspension of clay-sized (< 10 μm) particles. Biofilms were grown in replicate 3-m-long recirculating flumes over variable lengths of time (0, 14, 21, 28, and 35) days. Fixed doses of fluorescent clay-sized particles were introduced to each flume and their deposition was traced over 30 minutes. A flood event was then simulated via a step increase in flowrate to quantify particle resuspension. 3D Optical Coherence Tomography was used to determine roughness, areal coverage and height of biofilms in each flume. From these measurements we characterised particle deposition and resuspension rates, using continuous time random walk modelling techniques, which we then tested as responses to changes in biofilm coverage and structure under both base-flow and flood-flow scenarios. Our results suggest that biofilm structural complexity is a primary control upon the retention and downstream transport of fine particles in stream mesocosms.

  11. Aqueous biphasic extraction process with pH and particle control

    DOEpatents

    Chaiko, David J.; Mensah-Biney, R.

    1995-01-01

    A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay.

  12. Aqueous biphasic extraction process with pH and particle control

    DOEpatents

    Chaiko, D.J.; Mensah-Biney, R.

    1995-05-02

    A process for aqueous biphasic extraction of metallic oxides and the like from substances containing silica. Control of media pH enables efficient and effective partition of mixture components. The inventive method may be employed to remove excess silica from kaolin clay. 2 figs.

  13. Immobilization of horseradish peroxidase on NH2-modified magnetic Fe3O4/SiO2 particles and its application in removal of 2,4-dichlorophenol.

    PubMed

    Chang, Qing; Tang, Heqing

    2014-09-29

    Fe3O4 nanoparticles were prepared by a co-precipitation method with the assistance of ultrasound irradiation, and then coated with silica generated by hydrolysis and condensation of tetraethoxysilane. The silica-coated Fe3O4 nanoparticles were further modified with 3-aminopropyltriethoxysilane, resulting in anchoring of primary amine groups on the surface of the particles. Horseradish peroxidase (HRP) was then immobilized on the magnetic core-shell particles by using glutaraldehyde as a crosslinking agent. Immobilization conditions were optimized to obtain the highest relative activity of the immobilized enzyme. It was found the durability of the immobilized enzyme to heating and pH variation were improved in comparison with free HRP. The apparent Michaelis constants of the immobilized HRP and free HRP with substrate were compared, showing that the enzyme activity of the immobilized HRP was close to that of free HRP. The HRP immobilized particles, as an enzyme catalyst, were used to activate H2O2 for degrading 2,4-dichlorophenol. The rapid degradation of 2,4-dichlorophenol indicated that the immobilized enzyme has potential applications for removing organic pollutants.

  14. Improving nitrogen removal using a fuzzy neural network-based control system in the anoxic/oxic process.

    PubMed

    Huang, Mingzhi; Ma, Yongwen; Wan, Jinquan; Wang, Yan; Chen, Yangmei; Yoo, Changkyoo

    2014-10-01

    Due to the inherent complexity, uncertainty, and posterity in operating a biological wastewater treatment process, it is difficult to control nitrogen removal in the biological wastewater treatment process. In order to cope with this problem and perform a cost-effective operation, an integrated neural-fuzzy control system including a fuzzy neural network (FNN) predicted model for forecasting the nitrate concentration of the last anoxic zone and a FNN controller were developed to control the nitrate recirculation flow and realize nitrogen removal in an anoxic/oxic (A/O) process. In order to improve the network performance, a self-learning ability embedded in the FNN model was emphasized for improving the rule extraction performance. The results indicate that reasonable forecasting and control performances had been achieved through the developed control system. The effluent COD, TN, and the operation cost were reduced by about 14, 10.5, and 17 %, respectively.

  15. The fate of Transparent Exopolymer Particles (TEP) in integrated membrane systems: removal through pre-treatment processes and deposition on reverse osmosis membranes.

    PubMed

    Villacorte, Loreen O; Kennedy, Maria D; Amy, Gary L; Schippers, Jan C

    2009-12-01

    The abundance of Transparent Exopolymer Particles (TEP) in surface waters has been unnoticed for many years until recently as a potential foulant in reverse osmosis systems. Recent studies indicate that TEP may cause organic and biological fouling and may enhance particulate/colloidal fouling in reverse osmosis membranes. The presence of TEP was measured in the raw water, the pre-treatment processes and reverse osmosis (RO) systems of 6 integrated membrane installations. A spectrophotometric method was used to measure TEP in the particulate size range (>0.40microm) and was extended to measure TEP in the colloidal size range (0.05-0.40microm). Ultrafiltration pre-treatment applied in 4 plants, totally removed particulate TEP while microfiltration systems (2 plants) and coagulation/sedimentation/rapid sand filtration systems (3 plants) partially removed this fraction. None of the pre-treatment systems investigated totally removed colloidal TEP. Biopolymer analysis using LC-OCD showed consistency between colloidal TEP and polysaccharide removal by UF pre-treatment and further verified the presence of TEP in the RO feedwater. TEP deposition in the RO system was determined after measuring total TEP concentrations in the RO feed and concentrate. The TEP deposition factors and specific deposition rates indicate that TEP accumulation had occurred in all plants investigated. This observation was verified by an autopsy of RO modules from two RO plants. Further improvement and verification of the (modified) TEP method, in particular the calibration, is necessary so that it can be employed to investigate the role of TEP in the fouling of RO systems.

  16. Thrust Removal Scheme for the FAST-MAC Circulation Control Model Tested in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Chan, David T.; Milholen, William E., II; Jones, Gregory S.; Goodliff, Scott L.

    2014-01-01

    A second wind tunnel test of the FAST-MAC circulation control semi-span model was recently completed in the National Transonic Facility at the NASA Langley Research Center. The model allowed independent control of four circulation control plenums producing a high momentum jet from a blowing slot near the wing trailing edge that was directed over a 15% chord simple-hinged flap. The model was configured for transonic testing of the cruise configuration with 0deg flap deflection to determine the potential for drag reduction with the circulation control blowing. Encouraging results from analysis of wing surface pressures suggested that the circulation control blowing was effective in reducing the transonic drag on the configuration, however this could not be quantified until the thrust generated by the blowing slot was correctly removed from the force and moment balance data. This paper will present the thrust removal methodology used for the FAST-MAC circulation control model and describe the experimental measurements and techniques used to develop the methodology. A discussion on the impact to the force and moment data as a result of removing the thrust from the blowing slot will also be presented for the cruise configuration, where at some Mach and Reynolds number conditions, the thrust-removed corrected data showed that a drag reduction was realized as a consequence of the blowing.

  17. Tick Removal

    MedlinePlus

    ... There are several tick removal devices on the market, but a plain set of fine-tipped tweezers ... for Disease Control and Prevention National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) Division of Vector- ...

  18. Control of both particle and pore size in nanoporous palladium alloy powders

    SciTech Connect

    Jones, Christopher G.; Cappillino, Patrick J.; Stavila, Vitalie; Robinson, David B.

    2014-07-15

    Energy storage materials often involve chemical reactions with bulk solids. Porosity within the solids can enhance reaction rates. The porosity can be either within or between individual particles of the material. Greater control of the size and uniformity of both types of pore should lead to enhancements of charging and discharging rates in energy storage systems. Furthermore, to control both particle and pore size in nanoporous palladium (Pd)-based hydrogen storage materials, first we created uniformly sized copper particles of about 1 μm diameter by the reduction of copper sulfate with ascorbic acid. In turn, these were used as reducing agents for tetrachloropalladate in the presence of a block copolymer surfactant. The copper reductant particles are geometrically self-limiting, so the resulting Pd particles are of similar size. The surfactant induces formation of 10 nm-scale pores within the particles. Some residual copper is alloyed with the Pd, reducing hydrogen storage capacity; use of a more reactive Pd salt can mitigate this. The reaction is conveniently performed in gram-scale batches.

  19. Controlled endolysosomal release of agents by pH-responsive polymer blend particles

    PubMed Central

    Zhan, Xi; Tran, Kenny K.; Wang, Liguo; Shen, Hong

    2015-01-01

    Purpose A key step of delivering extracellular agents to its intracellular target is to escape from endosomal/lysosomal compartments, while minimizing the release of digestive enzymes that may compromise cellular functions. In this study, we examined the intracellular distribution of both fluorecent cargoes and enzymes by a particle delivery platform made from the controlled blending of poly (lactic-co-glycolic acid) (PLGA) and a random pH-sensitive copolymer. Methods We utilized both microscopic and biochemical methods to semi-quantitatively assess how the composition of blend particles affects the level of endosomal escape of cargos of various sizes and enzymes into the cytosolic space. Results We demonstrated that these polymeric particles enabled the controlled delivery of cargos into the cytosolic space that was more dependent on the cargo size and less on the composition of blend particles. Blend particles did not induce the rupture of endosomal/lysosomal compartments and released less than 20% of endosomal/lysosomal enzymes. Conclusions This study provides insight into understanding the efficacy and safety of a delivery system for intracellular delivery of biologics and drugs. Blend particles offer a potential platform to target intracellular compartments while potentially minimizing cellular toxicity. PMID:25592550

  20. Control of both particle and pore size in nanoporous palladium alloy powders

    DOE PAGES

    Jones, Christopher G.; Cappillino, Patrick J.; Stavila, Vitalie; ...

    2014-07-15

    Energy storage materials often involve chemical reactions with bulk solids. Porosity within the solids can enhance reaction rates. The porosity can be either within or between individual particles of the material. Greater control of the size and uniformity of both types of pore should lead to enhancements of charging and discharging rates in energy storage systems. Furthermore, to control both particle and pore size in nanoporous palladium (Pd)-based hydrogen storage materials, first we created uniformly sized copper particles of about 1 μm diameter by the reduction of copper sulfate with ascorbic acid. In turn, these were used as reducing agentsmore » for tetrachloropalladate in the presence of a block copolymer surfactant. The copper reductant particles are geometrically self-limiting, so the resulting Pd particles are of similar size. The surfactant induces formation of 10 nm-scale pores within the particles. Some residual copper is alloyed with the Pd, reducing hydrogen storage capacity; use of a more reactive Pd salt can mitigate this. The reaction is conveniently performed in gram-scale batches.« less

  1. Particle analyzing method and apparatus

    NASA Technical Reports Server (NTRS)

    Sinha, M. P.; Griffin, C. E.; Norris, D. D.; Friedlander, S. K. (Inventor)

    1980-01-01

    The rapid chemical analysis of particles in aerosols can be accomplished using an apparatus which produces a controlled stream of individual particles from an environment, and another apparatus which vaporizes and ionizes the particles moving in free flight, for analysis by a mass spectrometer. The device for producing the stream of particles includes a capillary tube through which the air with suspended particles moves, a skimmer with a small opening spaced from an end of the capillary tube to receive particles passing through the tube, and a vacuum pump which removes air from between the tube and skimmer and creates an inflow of air and particles through the tube. The particles passing through the skimmer opening can be simultaneously vaporized and ionized while in free flight, by a laser beam of sufficient intensity that is directed across the path of the free flying particles.

  2. Integrity breaches in a hollow fiber nanofilter - Effects on natural organic matter and virus-like particle removal.

    PubMed

    Lidén, Angelica; Lavonen, Elin; Persson, Kenneth M; Larson, Magnus

    2016-11-15

    Ultrafiltration and nanofiltration have become common methods to treat surface water for drinking water purposes. Common aims of a membrane step are removal of natural organic matter (NOM), softening or adding an extra microbiological or chemical barrier. In most cases, the membrane is considered a good disinfection step; commonly the viral removal is at least 4-log. To ensure a working disinfection, reliable integrity tests are required. In the present pilot study with a hollow fiber nanofilter, the membrane achieved a high NOM reduction, and the difference in parameters related to NOM quality before and after treatment proved to be useful indicators of integrity breaches. Changes in total organic carbon (TOC) concentration, UV-absorbance at 254 nm (UVA254) and fluorescence derived parameters in the permeate flow were related to leaking fibers. On average, UVA254 in the permeate was 3 times higher for a membrane with compromised fibers (0.041 cm(-1)) compared to an intact membrane (0.013 cm(-1)), while TOC was less than 2 times as high on average. Thus, this membrane had a higher reduction of UVA254 than TOC and the sensitivity for changes from leakage was higher. Therefore, it is suggested that UVA254 could be used as an indicator for membrane integrity. Additionally, there is a significant (P < 0.01) difference in fluorescence derived parameters between a leaking and an intact fiber, showing that fluorescence also has potential to be applied for online monitoring of membrane processes. During fiber failure, around 2% of the permeate flow passes through one single leaking fiber. The transport depends on the distance between the inflow and the leak, which in most cases are similar and most likely close to the middle of the fiber.

  3. Role of Polymer Segment-Particle Surface Interactions in Controlling Nanoparticle Dispersions in Concentrated Polymer Solutions

    SciTech Connect

    Kim, So Youn; Zukoski, Charles F.

    2014-09-24

    The microstructure of particles suspended in concentrated polymer solutions is examined with small-angle X-ray scattering and small-angle neutron scattering. Of interest are changes to long wavelength particle density fluctuations in ternary mixtures of silica nanoparticles suspended in concentrated solutions of poly(ethylene glycol). The results are understood in terms of application of the pseudo-two-component polymer reference interaction site model (PRISM) theory modified to account for solvent addition via effective contact strength of interfacial attraction, εpc, in an implicit manner. The combined experimental-theoretical study emphasizes the complex interactions between solvent, polymer, and particle surface that control particle miscibility but also demonstrate that these factors can all be understood in terms of variations of εpc.

  4. A particle temperature sensor for monitoring and control of the thermal spray process

    SciTech Connect

    Swank, W.D.; Fincke, J.R.; Haggard, D.C.

    1995-12-01

    The temperature and velocity of thermally sprayed particles prior to their impact on the substrate are two of the predominant determinants of coating quality and characteristics. This paper describes an instrument developed for real time monitoring of in-flight particle temperature in an industrial environment. The instrument is designed to operate as a stand alone device for verifying that a desired particle temperature is attained or for developing process settings to yield a particular temperature. The device is also suitable for incorporation into a closed loop process controller. Data showing the relationship between torch parameters and average particle temperature are presented. There is good agreement between previous measurements using laboratory instrumentation and the simpler, industrially hardened technique described here. The assumption of gray body behavior is evaluated and for known emissivities corrections are developed.

  5. Controlled Synthesis and Magnetic Properties of Uniform Hierarchical Polyhedral α-Fe2O3 Particles

    NASA Astrophysics Data System (ADS)

    Long, Nguyen Viet; Yang, Yong; Thi, Cao Minh; Phuc, Le Hong; Nogami, Masayuki

    2017-02-01

    The controlled synthesis of uniform hierarchical polyhedral iron (Fe) micro-/nanoscale oxide particles with the α-Fe2O3 structure is presented. The hierarchical polyhedral iron oxide particles were synthesized by modified polyol methods with sodium borohydride as a powerful and efficient reducing agent. A critical heat treatment process used during the synthesis allowed for the interesting formation of α-Fe2O3 hematite with a micro-/nanoscale structure. The structure and weak ferromagnetism of the α-Fe2O3 particles were investigated by x-ray diffraction with whole pattern fitting and Rietveld refinement, scanning electron microscopy, and by vibrating sample magnetometry. The as-prepared α-Fe2O3 particles and the three dimensional models presented have promising practical applications for energy storage and conversion in batteries, capacitors, and fuel cells, and related spintronic devices and technologies.

  6. Synergistic mercury removal by conventional pollutant control strategies for coal-fired power plants in China.

    PubMed

    Wang, Shuxiao; Zhang, Lei; Wu, Ye; Ancora, Maria Pia; Zhao, Yu; Hao, Jiming

    2010-06-01

    China's 11th 5-yr plan has regulated total sulfur dioxide (SO2) emissions by installing flue gas desulfurization (FGD) devices and shutting down small thermal power units. These control measures will not only significantly reduce the emission of conventional pollutants but also benefit the reduction of mercury emissions from coal-fired power plants. This paper uses the emission factor method to estimate the efficiencies of these measures on mercury emission abatement. From 2005 to 2010, coal consumption in power plants will increase by 59%; however, the mercury emission will only rise from 141 to 155 t, with an increase of 10%. The average emission rate of mercury from coal burning will decrease from 126 mg Hg/t of coal to 87 mg Hg/t of coal. The effects of the three desulfurization measures were assessed and show that wet FGD will play an important role in mercury removal. Mercury emissions in 2015 and 2020 are also projected under different policy scenarios. Under the most probable scenario, the total mercury emission in coal-fired power plants in China will decrease to 130 t by 2020, which will benefit from the rapid installation of fabric filters and selective catalytic reduction.

  7. PDE12 removes mitochondrial RNA poly(A) tails and controls translation in human mitochondria.

    PubMed

    Rorbach, Joanna; Nicholls, Thomas J J; Minczuk, Michal

    2011-09-01

    Polyadenylation of mRNA in human mitochondria is crucial for gene expression and perturbation of poly(A) tail length has been linked to a human neurodegenerative disease. Here we show that 2'-phosphodiesterase (2'-PDE), (hereafter PDE12), is a mitochondrial protein that specifically removes poly(A) extensions from mitochondrial mRNAs both in vitro and in mitochondria of cultured cells. In eukaryotes, poly(A) tails generally stabilize mature mRNAs, whereas in bacteria they increase mRNA turnover. In human mitochondria, the effects of increased PDE12 expression were transcript dependent. An excess of PDE12 led to an increase in the level of three mt-mRNAs (ND1, ND2 and CytB) and two (CO1 and CO2) were less abundant than in mitochondria of control cells and there was no appreciable effect on the steady-state level of the remainder of the mitochondrial transcripts. The alterations in poly(A) tail length accompanying elevated PDE12 expression were associated with severe inhibition of mitochondrial protein synthesis, and consequently respiratory incompetence. Therefore, we propose that mRNA poly(A) tails are important in regulating protein synthesis in human mitochondria, as it is the case for nuclear-encoded eukaryotic mRNA.

  8. Methods and apparatus for removal and control of material in laser drilling of a borehole

    DOEpatents

    Rinzler, Charles C; Zediker, Mark S; Faircloth, Brian O; Moxley, Joel F

    2014-01-28

    The removal of material from the path of a high power laser beam during down hole laser operations including drilling of a borehole and removal of displaced laser effected borehole material from the borehole during laser operations. In particular, paths, dynamics and parameters of fluid flows for use in conjunction with a laser bottom hole assembly.

  9. Methods and apparatus for removal and control of material in laser drilling of a borehole

    DOEpatents

    Rinzler, Charles C.; Zediker, Mark S.; Faircloth, Brian O.; Moxley, Joel F.

    2016-12-06

    The removal of material from the path of a high power laser beam during down hole laser operations including drilling of a borehole and removal of displaced laser effected borehole material from the borehole during laser operations. In particular, paths, dynamics and parameters of fluid flows for use in conjunction with a laser bottom hole assembly.

  10. Digital atom interferometer with single particle control on a discretized space-time geometry.

    PubMed

    Steffen, Andreas; Alberti, Andrea; Alt, Wolfgang; Belmechri, Noomen; Hild, Sebastian; Karski, Michał; Widera, Artur; Meschede, Dieter

    2012-06-19

    Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 x 10(-4) in units of gravitational acceleration g.

  11. Controlling dispersion forces between small particles with artificially created random light fields.

    PubMed

    Brügger, Georges; Froufe-Pérez, Luis S; Scheffold, Frank; José Sáenz, Juan

    2015-06-22

    Appropriate combinations of laser beams can be used to trap and manipulate small particles with optical tweezers as well as to induce significant optical binding forces between particles. These interaction forces are usually strongly anisotropic depending on the interference landscape of the external fields. This is in contrast with the familiar isotropic, translationally invariant, van der Waals and, in general, Casimir-Lifshitz interactions between neutral bodies arising from random electromagnetic waves generated by equilibrium quantum and thermal fluctuations. Here we show, both theoretically and experimentally, that dispersion forces between small colloidal particles can also be induced and controlled using artificially created fluctuating light fields. Using optical tweezers as a gauge, we present experimental evidence for the predicted isotropic attractive interactions between dielectric microspheres induced by laser-generated, random light fields. These light-induced interactions open a path towards the control of translationally invariant interactions with tuneable strength and range in colloidal systems.

  12. Controlling dispersion forces between small particles with artificially created random light fields

    PubMed Central

    Brügger, Georges; Froufe-Pérez, Luis S.; Scheffold, Frank; José Sáenz, Juan

    2015-01-01

    Appropriate combinations of laser beams can be used to trap and manipulate small particles with optical tweezers as well as to induce significant optical binding forces between particles. These interaction forces are usually strongly anisotropic depending on the interference landscape of the external fields. This is in contrast with the familiar isotropic, translationally invariant, van der Waals and, in general, Casimir–Lifshitz interactions between neutral bodies arising from random electromagnetic waves generated by equilibrium quantum and thermal fluctuations. Here we show, both theoretically and experimentally, that dispersion forces between small colloidal particles can also be induced and controlled using artificially created fluctuating light fields. Using optical tweezers as a gauge, we present experimental evidence for the predicted isotropic attractive interactions between dielectric microspheres induced by laser-generated, random light fields. These light-induced interactions open a path towards the control of translationally invariant interactions with tuneable strength and range in colloidal systems. PMID:26096622

  13. Controlling the motion and placement of micrometer-sized metal particles using patterned polymer brush surfaces.

    PubMed

    Dunderdale, Gary J; Howse, Jonathan R; Fairclough, J Patrick A

    2011-10-04

    In this paper, we show that silicon surfaces patterned with poly(methacrylic acid) brushes are able to control the Brownian motion of 2-3 μm iron particles, which sediment onto the surface in aqueous solution and experience differences in repulsive force depending upon their position. Differences in repulsion lead to different gravitational potential energies across the surface, which gives bias to the Brownian motion taking place. Three regimes have been identified depending upon the brush height: (i) no control of Brownian motion when the brush height is small, (ii) Brownian motion that is influenced by the polymer brush when the brush 17 height is intermediate, (iii) Brownian motion that is confined by polymer brush barriers when the brush height is greatest. The height of brush found necessary to significantly influence iron particle motion was small at 39 nm or 2% of the particle diameter.

  14. Particle and Kalman filtering for state estimation and control of DC motors.

    PubMed

    Rigatos, Gerasimos G

    2009-01-01

    State estimation is a major problem in industrial systems. To this end, Gaussian and nonparametric filters have been developed. In this paper the Kalman Filter, which assumes Gaussian measurement noise, is compared to the Particle Filter, which does not make any assumption on the measurement noise distribution. As a case study the estimation of the state vector of a DC motor is used. The reconstructed state vector is used in a feedback control loop to generate the control input of the DC motor. In simulation tests it was observed that for a large number of particles the Particle Filter could succeed in accurately estimating the motor's state vector, but at the same time it required higher computational effort.

  15. Computer simulation of wolf-removal strategies for animal-damage control

    USGS Publications Warehouse

    Haight, R.G.; Travis, L.E.; Nimerfro, K.; Mech, L.D.

    2002-01-01

    Because of the sustained growth of the gray wolf (Canis lupus) population in the western Great Lakes region of the United States, management agencies are anticipating gray wolf removal from the federal endangered species list and are proposing strategies for wolf management. Strategies are needed that would balance public demand for wolf conservation with demand for protection against wolf depredation on livestock, poultry, and pets. We used a stochastic, spatially structured, individually based simulation model of a hypothetical wolf population, representing a small subset of the western Great Lakes wolves, to predict the relative performance of 3 wolf-removal strategies. Those strategies included reactive management (wolf removal occurred in summer after depredation), preventive management (wolves removed in winter from territories with occasional depredation), and population-size management (wolves removed annually in winter from all territories near farms). Performance measures included number of depredating packs and wolves removed, cost, and population size after 20 years. We evaluated various scenarios about immigration, trapping success, and likelihood of packs engaging in depredation. Four robust results emerged from the simulations: 1) each strategy reduced depredation by at least 40% compared with no action, 2) preventive and population-size management removed fewer wolves than reactive management because wolves were removed in winter before pups were born, 3)population-size management was least expensive because repeated annual removal kept most territories near farms free of wolves, and 4) none of the strategies threatened wolf populations unless they were isolated because wolf removal took place near farms and not in wild areas. For isolated populations, reactive management alone ensured conservation and reduced depredation. Such results can assist decision makers in managing gray wolves in the western Great Lakes states.

  16. Spatio-temporal controls of nitrate removal in a restored riparian groundwater system

    NASA Astrophysics Data System (ADS)

    Peter, Simone; Rechsteiner, Romana; Lehmann, Moritz; Tockner, Klement; Wehrli, Bernhard; Durisch-Kaiser, Edith

    2010-05-01

    of different control mechanisms directs the formation of a nitrate removal hotspot in a riparian floodplain. This knowledge is also highly vital for the design of appropriate measures in river floodplain restoration.

  17. Use of particle filters in an active control algorithm for noisy nonlinear structural dynamical systems

    NASA Astrophysics Data System (ADS)

    Sajeeb, R.; Manohar, C. S.; Roy, D.

    2007-09-01

    The problem of active control of nonlinear structural dynamical systems, in the presence of both process and measurement noises, is considered. The focus of the study is on the use of particle filters for state estimation in feedback control algorithms for nonlinear structures, when a limited number of noisy output measurements are available. The control design is done using the state-dependent Riccati equation (SDRE) method. The stochastic differential equations (SDEs) governing the dynamical systems are discretized using explicit forms of Ito-Taylor expansions. The Bayesian bootstrap filter and that based on sequential important sampling (SIS) are employed for state estimation. The simulation results show the feasibility of using particle filters and SDRE techniques in control of nonlinear structural dynamical systems.

  18. Examination of commercially available copper oxide wire particles for control of Haemonchus contorus in lambs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternatives to synthetic anthelmintics remain critical due to the prevalence of anthelmintic resistance. The objective of the experiment was to determine the efficacy of copper oxide wire particles (COWP) from three commercial sources to control Haemonchus contortus in lambs. Naturally infected Ka...

  19. Particle Size Controls on Water Adsorption and Condensation Regimes at Mineral Surfaces

    PubMed Central

    Yeşilbaş, Merve; Boily, Jean-François

    2016-01-01

    Atmospheric water vapour interacting with hydrophilic mineral surfaces can produce water films of various thicknesses and structures. In this work we show that mineral particle size controls water loadings achieved by water vapour deposition on 21 contrasting mineral samples exposed to atmospheres of up to ~16 Torr water (70% relative humidity at 25 °C). Submicrometer-sized particles hosted up to ~5 monolayers of water, while micrometer-sized particles up to several thousand monolayers. All films exhibited vibrational spectroscopic signals akin to liquid water, yet with a disrupted network of hydrogen bonds. Water adsorption isotherms were predicted using models (1- or 2- term Freundlich and Do-Do models) describing an adsorption and a condensation regime, respectively pertaining to the binding of water onto mineral surfaces and water film growth by water-water interactions. The Hygroscopic Growth Theory could also account for the particle size dependence on condensable water loadings under the premise that larger particles have a greater propensity of exhibiting of surface regions and interparticle spacings facilitating water condensation reactions. Our work should impact our ability to predict water film formation at mineral surfaces of contrasting particle sizes, and should thus contribute to our understanding of water adsorption and condensation reactions occuring in nature. PMID:27561325

  20. Particle Size Controls on Water Adsorption and Condensation Regimes at Mineral Surfaces

    NASA Astrophysics Data System (ADS)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-08-01

    Atmospheric water vapour interacting with hydrophilic mineral surfaces can produce water films of various thicknesses and structures. In this work we show that mineral particle size controls water loadings achieved by water vapour deposition on 21 contrasting mineral samples exposed to atmospheres of up to ~16 Torr water (70% relative humidity at 25 °C). Submicrometer-sized particles hosted up to ~5 monolayers of water, while micrometer-sized particles up to several thousand monolayers. All films exhibited vibrational spectroscopic signals akin to liquid water, yet with a disrupted network of hydrogen bonds. Water adsorption isotherms were predicted using models (1- or 2- term Freundlich and Do-Do models) describing an adsorption and a condensation regime, respectively pertaining to the binding of water onto mineral surfaces and water film growth by water-water interactions. The Hygroscopic Growth Theory could also account for the particle size dependence on condensable water loadings under the premise that larger particles have a greater propensity of exhibiting of surface regions and interparticle spacings facilitating water condensation reactions. Our work should impact our ability to predict water film formation at mineral surfaces of contrasting particle sizes, and should thus contribute to our understanding of water adsorption and condensation reactions occuring in nature.

  1. Chemical boundary conditions for the classification of aerosol particles using computer controlled electron probe microanalysis.

    PubMed

    Anaf, Willemien; Horemans, Benjamin; Van Grieken, René; De Wael, Karolien

    2012-11-15

    A method for the classification of individual aerosol particles using computer controlled electron probe microanalysis is presented. It is based on chemical boundary conditions (CBC) and enables quick and easy processing of a large set of elemental concentration data (mass%), derived from the X-ray spectra of individual particles. The particles are first classified into five major classes (sea salt related, secondary inorganic, minerals, iron-rich and carbonaceous), after which advanced data mining can be performed by examining the elemental composition of particles within each class into more detail (e.g., by ternary diagrams). The CBC method is validated and evaluated by comparing its results with the output obtained with hierarchical cluster analysis (HCA) for well-known standard particles as well as real aerosol particles collected with a cascade impactor. The CBC method gives reliable results and has a major advantage compared to HCA. CBC is based on boundary conditions that are derived from chemical logical thinking and does not require a translation of a mathematical algorithm output as does HCA. Therefore, the CBC method is more objective and enables comparison between samples without intermediate steps.

  2. Mind the gap: a flow instability controlled by particle-surface distance

    NASA Astrophysics Data System (ADS)

    Driscoll, Michelle; Delmotte, Blaise; Youssef, Mena; Sacanna, Stefano; Donev, Aleksandar; Chaikin, Paul

    2016-11-01

    Does a rotating particle always spin in place? Not if that particle is near a surface: rolling leads to translational motion, as well as very strong flows around the particle, even quite far away. These large advective flows strongly couple the motion of neighboring particles, giving rise to strong collective effects in groups of rolling particles. Using a model experimental system, weakly magnetic colloids driven by a rotating magnetic field, we observe that driving a compact group of microrollers leads to a new kind of flow instability. First, an initially uniformly-distributed strip of particles evolves into a shock structure, and then it becomes unstable, emitting fingers with a well-defined wavelength. Using 3D large-scale simulations in tandem with our experiments, we find that the instability wavelength is controlled not by the driving torque or the fluid viscosity, but a geometric parameter: the microroller's distance above the container floor. Furthermore, we find that the instability dynamics can be reproduced using only one ingredient: hydrodynamic interactions near a no-slip boundary.

  3. 40 CFR 63.9323 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pollutants for Engine Test Cells/Stands Testing and Initial Compliance Requirements § 63.9323 How do I... and test methods in this section to determine the add-on control device emission destruction or removal efficiency as part of the performance test required by § 63.9310. You must conduct three test...

  4. A frequency-control particle separation device based on resultant effects of electroosmosis and dielectrophoresis

    NASA Astrophysics Data System (ADS)

    Lin, Shiang-Chi; Tung, Yi-Chung; Lin, Chih-Ting

    2016-08-01

    Particle separation plays an important role in microfluidic sample preparation for various biomedical applications. In this paper, we report a particle manipulation and separation scheme using a microfluidic device based on low-volume/low-voltage electrokinetic frequency modulation. Utilizing a circular micro-electrode array, both electroosmosis and dielectrophoresis can be contributed to manipulate particles in the device by controlling the frequency of applied sinusoidal travelling wave signals. Theoretical simulations based on finite-element methods are employed to establish fundamental understanding of the developed scheme. For experimental demonstration, polystyrene beads (6 μm in diameter) and human promyelocytic leukaemia cells (HL-60) are used to validate the frequency-modulation effect. Furthermore, different diameter polystyrene beads (6 μm and 10 μm in diameter) are mixed to show potentials of precise particle separations (˜90% efficiency) by the reported frequency-controlled electrokinetic device. The developed technique can be exploited as an actuation scheme and particle manipulation method for microfluidic sample preparations of low ionic concentration samples.

  5. Peroxynitrite formation in nitric oxide-exposed submitochondrial particles: Detection, oxidative damage and catalytic removal by Mn-porphyrins

    PubMed Central

    Valez, Valeria; Cassina, Adriana; Batinic-Haberle, Ines; Kalyanaraman, Balaraman; Ferrer-Sueta, Gerardo; Radi, Rafael

    2012-01-01

    Peroxynitrite (ONOO−) formation in mitochondria may be favored due to the constant supply of superoxide radical (O2•−) by the electron transport chain plus the facile diffusion of nitric oxide (•NO) to this organelle. Herein, a model system of submitochondrial particles (SMP) in the presence of succinate plus the respiratory inhibitor antimycin A (to increase O2•− rates) and the •NO-donor NOC-7 was studied to directly establish and quantitate peroxynitrite by a multiplicity of methods including chemiluminescence, fluorescence and immunochemical analysis. While all the tested probes revealed peroxynitrite at near stoichiometric levels with respect to its precursor radicals, coumarin boronic acid (a probe that directly reacts with peroxynitrite) had the more straightforward oxidation profile from O2•−-forming SMP as a function of the •NO flux. Interestingly, immunospintrapping studies verified protein radical generation in SMP by peroxynitrite. Substrate-supplemented SMP also reduced Mn(III)porphyrins (MnP) to Mn(II)P under physiologically-relevant oxygen levels (3–30 μM); then, Mn(II)P were capable to reduce peroxynitrite and protect SMP from the inhibition of complex I-dependent oxygen consumption and protein radical formation and nitration of membranes. The data directly support the formation of peroxynitrite in mitochondria and demonstrate that MnP can undergo a catalytic redox cycle to neutralize peroxynitrite-dependent mitochondrial oxidative damage. PMID:23142682

  6. 2,4-dichlorophenol enzymatic removal and its kinetic study using HRP crosslinked to nano spray dried poly(lactic-co-glycolic acid) fine particles.

    PubMed

    Dahili, Laura Amina; Nagy, Endre; Feczkó, Tivadar

    2017-02-07

    Horseradish peroxidase (HRP) catalyzes the oxidation of aromatic compounds by hydrogen peroxide via insoluble polymer formation, which can be precipitated from the wastewater. For HRP immobilization poly(lactic-co-glycolic acid) (PLGA) fine carrier supports were produced by Nano Spray Dryer B-90. Immobilized HRP was used to remove the persistent 2,4-dichlorophenol from model wastewater. Both extracted (9-16 U/g) and purified HRP (11-25 U/g) retained their activity to a high extent after crosslinking to the PLGA particles. The immobilized enzyme activity was substantially higher in both of the acidic and the alkaline pH region compared to the free enzyme. Optimally 98 % of the 2,4-dichlorophenol could be eliminated using immobilized HRP due to catalytic removal and partly to adsorption on the carrier supports. Immobilized enzyme kinetics for 2,4-dichlorophenol elimination was studied for the first time, and it could be concluded that competitive product inhibition took place.

  7. Observation and Control of Hamiltonian Chaos in Wave-particle Interaction

    SciTech Connect

    Doveil, F.; Ruzzon, A.; Elskens, Y.

    2010-11-23

    Wave-particle interactions are central in plasma physics. The paradigm beam-plasma system can be advantageously replaced by a traveling wave tube (TWT) to allow their study in a much less noisy environment. This led to detailed analysis of the self-consistent interaction between unstable waves and an either cold or warm electron beam. More recently a test cold beam has been used to observe its interaction with externally excited wave(s). This allowed observing the main features of Hamiltonian chaos and testing a new method to efficiently channel chaotic transport in phase space. To simulate accurately and efficiently the particle dynamics in the TWT and other 1D particle-wave systems, a new symplectic, symmetric, second order numerical algorithm is developed, using particle position as the independent variable, with a fixed spatial step.This contribution reviews: presentation of the TWT and its connection to plasma physics, resonant interaction of a charged particle in electrostatic waves, observation of particle trapping and transition to chaos, test of control of chaos, and description of the simulation algorithm.The velocity distribution function of the electron beam is recorded with a trochoidal energy analyzer at the output of the TWT. An arbitrary waveform generator is used to launch a prescribed spectrum of waves along the 4m long helix of the TWT. The nonlinear synchronization of particles by a single wave, responsible for Landau damping, is observed. We explore the resonant velocity domain associated with a single wave as well as the transition to large scale chaos when the resonant domains of two waves and their secondary resonances overlap. This transition exhibits a devil's staircase behavior when increasing the excitation level in agreement with numerical simulation.A new strategy for control of chaos by building barriers of transport in phase space as well as its robustness is successfully tested. The underlying concepts extend far beyond the field of

  8. Particle control challenges in process chemicals and ultra-pure water for sub-10nm technology nodes

    NASA Astrophysics Data System (ADS)

    Rastegar, Abbas; Samayoa, Martin; House, Matthew; Kurtuldu, Hüseyin; Eah, Sang-Kee; Morse, Lauren; Harris-Jones, Jenah

    2014-04-01

    Particle contamination in ultra-pure water (UPW) and chemicals will eventually end up on the surface of a wafer and may result in killer defects. To improve the semiconductor processing yield in sub-10 nm half pitch nodes, it is necessary to control particle defectivity. In a systematic study of all major techniques for particle detection, counting, and sizing in solutions, we have shown that there is a gap in the required particle metrology which needs to be addressed by the industry. To reduce particles in solutions and improve filter retention for sub-10 nm particles with very low densities (<10 particles/mL), liquid particle counters that are able to detect small particles at low densities are required. Non-volatile residues in chemicals and UPW can result in nanoparticles. Measuring absolute non-volatile residues in UPW with concentrations in the ppb range is a challenge. However, by using energy-dispersive spectroscopy (EDS) analysis through transmission electron microscopy (TEM) of non-volatile residues we found silica both in dissolved and colloidal particle form which is present in one of the cleanest UPW that we tested. A particle capture/release technique was developed at SEMATECH which is able to collect particles from UPW and release them in a controlled manner. Using this system we showed sub-10 nm particles are present in UPW. In addition to colloidal silica, agglomerated carbon containing particles were also found in UPW.

  9. Noninvasive control of dental calculus removal: qualification of two fluorescence methods

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Biryukova, T.

    2013-02-01

    The main condition of periodontitis prevention is the full calculus removal from the teeth surface. This procedure should be fulfilled without harming adjacent unaffected tooth tissues. Nevertheless the problem of sensitive and precise estimating of tooth-calculus interface exists and potential risk of hard tissue damage remains. In this work it was shown that fluorescence diagnostics during calculus removal can be successfully used for precise noninvasive detection of calculus-tooth interface. In so doing the simple implementation of this method free from the necessity of spectrometer using can be employed. Such a simple implementation of calculus detection set-up can be aggregated with the devices of calculus removing.

  10. Characterization and Control of Airborne Particles Emitted During Production of Epoxy / Carbon Nanotube Nanocomposites

    PubMed Central

    Cena, Lorenzo G.; Peters, Thomas M.

    2016-01-01

    This work characterized airborne particles that were generated from the weighing of bulk, multi-wall carbon nanotubes (CNTs) and the manual sanding of epoxy test samples reinforced with CNTs. It also evaluated the effectiveness of three local exhaust ventilation (LEV) conditions (no LEV, custom fume hood, and biosafety cabinet) for control of particles generated during sanding of CNT-epoxy nanocomposites. Particle number and respirable mass concentrations were measured using an optical particle counter (OPC) and a condensation particle counter (CPC), and particle morphology was assessed by transmission electron microscopy. The ratios of the geometric mean (GM) concentrations measured during the process to that measured in the background (P/B ratios) were used as indices of the impact of the process and the LEVs on observed concentrations. Processing CNT-epoxy nanocomposites materials released respirable size airborne particles (P/B ratio: weighing = 1.79; sanding = 5.90) but generally no nanoparticles (P/B ratiô1). The particles generated during sanding were predominately micron-sized with protruding CNTs and very different from bulk CNTs that tended to remain in large (>1 μm) tangled clusters. Respirable mass concentrations in the operator’s breathing zone were lower when sanding was performed in the biological safety cabinet (GM = 0.20 μg/m3) compared to those with no LEV (GM = 2.68 μg/m3) or those when sanding was performed inside the fume hood (GM = 21.4 μg/m3; p-value < 0.0001). The poor performance of the custom fume hood used in this study may have been exacerbated by its lack of a front sash and rear baffles and its low face velocity (0.39 m/sec). PMID:21253981

  11. Particle size tailoring of ursolic acid nanosuspensions for improved anticancer activity by controlled antisolvent precipitation.

    PubMed

    Wang, Yancai; Song, Ju; Chow, Shing Fung; Chow, Albert H L; Zheng, Ying

    2015-10-15

    The present study was aimed at tailoring the particle size of ursolic acid (UA) nanosuspension for improved anticancer activity. UA nanosuspensions were prepared by antisolvent precipitation using a four-stream multi-inlet vortex mixer (MIVM) under defined conditions of varying solvent composition, drug feeding concentration or stream flow rate. The resulting products were characterized for particle size and polydispersity. Two of the UA nanosuspensions with mean particle sizes of 100 and 300 nm were further assessed for their in-vitro activity against MCF-7 breast cancer cells using fluorescence microscopy with 4',6-diamidino-2-phenylindole (DAPI) staining, as well as flow cytometry with propidium (PI) staining and with double staining by fluorescein isothiocyanate. It was revealed that the solvent composition, drug feeding concentration and stream flow rate were critical parameters for particle size control of the UA nanosuspensions generated with the MIVM. Specifically, decreasing the UA feeding concentration or increasing the stream flow rate or ethanol content resulted in a reduction of particle size. Excellent reproducibility for nanosuspension production was demonstrated for the 100 and 300 nm UA preparations with a deviation of not more than 5% in particle size from the mean value of three independent batches. Fluorescence microscopy and flow cytometry revealed that these two different sized UA nanosuspensions, particularly the 300 nm sample, exhibited a higher anti-proliferation activity against the MCF-7 cells and afforded a larger population of these cells in both early and late apoptotic phases. In conclusion, MIVM is a robust and pragmatic tool for tailoring the particle size of the UA nanosuspension. Particle size appears to be a critical determinant of the anticancer activity of the UA nanoparticles.

  12. Mutation particle swarm optimization of the BP-PID controller for piezoelectric ceramics

    NASA Astrophysics Data System (ADS)

    Zheng, Huaqing; Jiang, Minlan

    2016-01-01

    PID control is the most common used method in industrial control because its structure is simple and it is easy to implement. PID controller has good control effect, now it has been widely used. However, PID method has a few limitations. The overshoot of the PID controller is very big. The adjustment time is long. When the parameters of controlled plant are changing over time, the parameters of controller could hardly change automatically to adjust to changing environment. Thus, it can't meet the demand of control quality in the process of controlling piezoelectric ceramic. In order to effectively control the piezoelectric ceramic and improve the control accuracy, this paper replaced the learning algorithm of the BP with the mutation particle swarm optimization algorithm(MPSO) on the process of the parameters setting of BP-PID. That designed a better self-adaptive controller which is combing the BP neural network based on mutation particle swarm optimization with the conventional PID control theory. This combination is called the MPSO-BP-PID. In the mechanism of the MPSO, the mutation operation is carried out with the fitness variance and the global best fitness value as the standard. That can overcome the precocious of the PSO and strengthen its global search ability. As a result, the MPSO-BP-PID can complete controlling the controlled plant with higher speed and accuracy. Therefore, the MPSO-BP-PID is applied to the piezoelectric ceramic. It can effectively overcome the hysteresis, nonlinearity of the piezoelectric ceramic. In the experiment, compared with BP-PID and PSO-BP-PID, it proved that MPSO is effective and the MPSO-BP-PID has stronger adaptability and robustness.

  13. Simulation and control of morphological changes due to dam removal in the Sandy River, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Ding, Y.; Altinakar, M. S.

    2015-03-01

    A one-dimensional channel evolution simulation model (CCHE1D) is applied to assess morphological changes in a reach of the Sandy River, Oregon, USA, due to the Marmot Dam removal in 2007. Sediment transport model parameters (e.g. sediment transport capacity, bed roughness coefficient) were calibrated using observed bed changes after the dam removal. The validated model is then applied to assess long-term morphological changes in response to a 10-year hydrograph selected from historical storm water records. The long-term assessment of sedimentation gives a reasonable prediction of morphological changes, expanding erosion in reservoir and growing deposition immediately downstream of the dam site. This prediction result can be used for managing and planning river sedimentation after dam removal. A simulation-based optimization model is also applied to determine the optimal sediment release rates during dam-removal that will minimize the morphological changes in the downstream reaches.

  14. Particles control in selective laser melting in-situ oxide dispersion strengthened method

    NASA Astrophysics Data System (ADS)

    Zhou, Xin; An, Zhibin; Shen, Zhijian; Liu, Wei; Yao, Chenguang

    2017-01-01

    Stainless steel selective laser melting (SLM) can be considered as a new possible approach for in-situ formation of oxide dispersion strengthened (ODS) steels because of the dispersion of amorphous oxide nano-particles due to the trace amounts of laser chamber oxygen and in-situ internal oxidation of reactive elements. In this paper it is demonstrated that the particle sizes and distributions can be adjusted by choosing different chamber oxygen level through controlling the quantity of initial reactive cores and the available reactive solutes of each core.

  15. Influence of Air Humidity and Water Particles on Dust Control Using Ultrasonic Atomization

    NASA Astrophysics Data System (ADS)

    Okawa, Hirokazu; Nishi, Kentaro; Shindo, Dai; Kawamura, Youhei

    2012-07-01

    The influence of air humidity and water particles on dust control was examined using ultrasonic atomization at 2.4 MHz, an acrylic box (61 L), and four types of ore dust samples: green tuff (4 µm), green tuff (6 µm), kaolin, and silica. It was clearly demonstrated that ultrasonic atomization was effective in raising humidity rapidly. However, at high relative air humidity, the water particles remained stable in the box without changing to water vapor. Ultrasonic atomization was applied to suppress dust dispersion and 40-95% dust reduction was achieved at 83% relative air humidity. Dust dispersion was more effective with ultrasonic atomization than without.

  16. Controlled modulation of laser beam and dynamic patterning of colloidal particles using optical tweezers

    NASA Astrophysics Data System (ADS)

    Singh, Brijesh Kumar; Singh Mehta, Dalip; Kumar, Ranjeet; Senthilkumaran, Paramasivam

    2016-02-01

    We present controlled generation of complex-structured beam profiles using diffractive optical element and demonstrate multiple dynamic trapping of colloidal particles. The phase element is programmed to generate various tailored optical fields having structures, similar to that of number three, spiral, and circle but in a tractable manner. Thus, the generated spatially tailored optical fields are confined to focal volume in optical tweezers. This enabled real-time trapping of multiple microscopic objects whereby its transverse organization was controlled in a dynamic manner from one structure to another with the help of spatial light modulator. Such a controlled beam shaping finds potential applications in biophotonics, super resolution imaging, and measurement of biophysical parameters, cell sorting, and micro-manipulation of colloidal particles.

  17. Ultraphosphate, a potent stain control agent that is effective for both stain removal and prevention of stain deposition.

    PubMed

    Koyasu, Masahiro; Shiba, Toshikazu; Kawazoe, Yumi; Manabe, Atsufumi; Miyazaki, Takashi

    2014-01-01

    Polyphosphate is a phosphate polymer which is effective for stain removal and prevention of stain deposition. Ultraphosphate belongs to the polyphosphate group and has a highly branched mesh-like structure. To evaluate stain control ability of ultraphosphate, we used HAP powder, glass-ionomer cement and detached human teeth for models of in vitro stain control experiments. When using HAP powder, the stain removal ability of ultraphosphate was the highest among common chelating agents. In addition, ultraphosphate efficiently removed stain and prevented stain deposition on glass-ionomer cement at 20°C and 37°C. Finally, ultraphosphate removed coffee stain from human teeth surface efficiently and the color difference (ΔE*ab) before and after ultraphosphate treatment was changed dramatically from 59.4 to 8.3. Similarly, the ΔE*ab value of human teeth treated with ultraphosphate before coffee treatment was only 9.9, while the value without ultraphosphate pre-treatment was 21.2. These results indicate that ultraphosphate is a potent agent for stain control.

  18. Removal of drone brood from Apis mellifera (Hymenoptera: Apidae) colonies to control Varroa destructor (Acari: Varroidae) and retain adult drones.

    PubMed

    Wantuch, Holly A; Tarpy, David R

    2009-12-01

    The parasitic mite Varroa destructor Anderson & Trueman (Acari: Varroidae) has plagued European honey bees, Apis mellifera L. (Hymenoptera: Apidae), in the Americas since its introduction in the 1980s. For many years, these mites were sufficiently controlled using synthetic acaricides. Recently, however, beekeepers have experienced increased resistance by mites to chemical pesticides, which are also known to leave residues in hive products such as wax and honey. Thus there has been increased emphasis on nonchemical integrated pest management control tactics for Varroa. Because mites preferentially reproduce in drone brood (pupal males), we developed a treatment strategy focusing on salvaging parasitized drones while removing mites from them. We removed drone brood from colonies in which there was no acaricidal application and banked them in separate "drone-brood receiving" colonies treated with pesticides to kill mites emerging with drones. We tested 20 colonies divided into three groups: 1) negative control (no mite treatment), 2) positive control (treatment with acaricides), and 3) drone-brood removal and placement into drone-brood receiving colonies. We found that drone-brood trapping significantly lowered mite numbers during the early months of the season, eliminating the need for additional control measures in the spring. However, mite levels in the drone-brood removal group increased later in the summer, suggesting that this benefit does not persist throughout the entire season. Our results suggest that this method of drone-brood trapping can be used as an element of an integrated control strategy to control varroa mites, eliminating a large portion of the Varroa population with limited chemical treatments while retaining the benefits of maintaining adult drones in the population.

  19. Integration of a particle monitor into the control system for an ion implanter

    NASA Astrophysics Data System (ADS)

    Myers, Steven; McCarron, David; Blake, Julian

    1993-04-01

    The value of in situ particle monitors for both manufacturing process control and process development in the semiconductor industry is receiving considerable recognition. This paper discusses the integration of a high yield technology (HYT) sensor into the control system of an Baton high current ion implanter. The automatic triggering of the particle monitor during the various phases of the implant process and the autoclean cycle provides a definite representation of the machine state and the effect of processing over time. Utilizing existing features of the control system, specific thresholds can be associated with each implant process through its process recipe. By regular monitoring of the particle counter, these thresholds are used to anticipate the need for cleaning the process chamber, or if indicated, gracefully bring the current process to an immediate halt. A dedicated history log preserves detailed data for generating summary statistics and the complete data set of a particular process or overall machine performance. Future uses of this tool with the control system point toward statistical process control applications and intelligent self modifying process cycles. The presentation will include data from a system on which an HYT sensor was employed as a full time process monitor using modified SPC techniques for analysis.

  20. A computer controlled television detector for light, X-rays and particles

    NASA Technical Reports Server (NTRS)

    Kalata, K.

    1981-01-01

    A versatile, high resolution, software configurable, two-dimensional intensified vidicon quantum detector system has been developed for multiple research applications. A thin phosphor convertor allows the detection of X-rays below 20 keV and non-relativistic particles in addition to visible light, and a thicker scintillator can be used to detect X-rays up to 100 keV and relativistic particles. Faceplates may be changed to allow any active area from 1 to 40 mm square, and active areas up to 200 mm square are possible. The image is integrated in a digital memory on any software specified array size up to 4000 x 4000. The array size is selected to match the spatial resolution, which ranges from 10 to 100 microns depending on the operating mode, the active area, and the photon or particle energy. All scan and data acquisition parameters are under software control to allow optimal data collection for each application.

  1. Strategies to control the particle size distribution of poly-epsilon-caprolactone nanoparticles for pharmaceutical applications.

    PubMed

    Lince, Federica; Marchisio, Daniele L; Barresi, Antonello A

    2008-06-15

    In this work turbulent precipitation through solvent displacement for the production of poly-epsilon-caprolactone (PCL) nanoparticles is investigated; two different PCL molecular weights have been employed, using acetone and water as solvent and anti-solvent, respectively. The main important thermodynamic and kinetic parameters, such as solubility and interfacial tension of PCL in water-acetone mixtures, are determined and the effect of the process operating conditions on the final particle size distribution is also investigated. Particles produced under different conditions into a Confined Impinging Jets Reactor (CIJR) were characterized by Dynamic Light Scattering, Zeta potential measurements and Scanning Electronic Microscopy. Results clearly show the strong effect of mixing on the particle size distribution and how mixing must be controlled in order to obtain a product with particular characteristics. Eventually the measured thermodynamic and kinetic parameters are used to interpret the obtained experimental data.

  2. Carbon Nanotube-Quantum Dot Nanohybrids: Coupling with Single-Particle Control in Aqueous Solution.

    PubMed

    Attanzio, Antonio; Sapelkin, Andrei; Gesuele, Felice; van der Zande, Arend; Gillin, William P; Zheng, Ming; Palma, Matteo

    2017-02-10

    A strategy is reported for the controlled assembly of organic-inorganic heterostructures consisting of individual single-walled carbon nanotubes (SWCNTs) selectively coupled to single semiconductor quantum dots (QDs). The assembly in aqueous solution was controlled towards the formation of monofunctionalized SWCNT-QD structures. Photoluminescence studies in solution, and on surfaces at the single nanohybrid level, showed evidence of electronic coupling between the two nanostructures. The ability to covalently couple heterostructures with single particle control is crucial for the design of novel QD-based optoelectronic and light-energy conversion devices.

  3. Surface-Engineered Graphene Quantum Dots for Shape Control of Block Copolymer Particles

    NASA Astrophysics Data System (ADS)

    Yang, Hyunseung; Ku, Kang Hee; Shin, Jae Man; Lee, Junhyuk; Park, Chan Ho; Cho, Han-Hee; Jang, Se Gyu; Kim, Bumjoon; KIST Collaboration

    Surface-engineered, 10 nm-sized graphene quantum dots (GQDs) are shown to be efficient surfactants for producing poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) particles that feature tunable shapes and internal morphologies. The surface properties of GQDs were modified by grafting different alkyl ligands, such as hexylamine and oleylamine, to generate the surfactant behavior of the GQDs. In stark contrast to the behavior of the unmodified GQDs, hexylamine-grafted GQDs and oleylamine-grafted GQD surfactants were selectively positioned on the PS and P4VP domains, respectively, at the surface of the particles. This positioning effectively tuned the interfacial interaction between two different PS/P4VP domains of the particles and the surrounding water during emulsification and induced a dramatic morphological transition to an unconventional convex lens-shaped particles. Precise and systematic control of interfacial activity of GQD surfactants was also demonstrated by varying the density of the alkyl ligands on the GQDs. The excellent surface tunability of 10 nm-sized GQDs combined with their significant optical and electrical properties highlight their importance as surfactants for producing colloidal particles with novel functions.

  4. A Comparison between Temperature-Controlled Laminar Airflow Device and a Room Air-Cleaner in Reducing Exposure to Particles While Asleep

    PubMed Central

    Spilak, Michal P.; Sigsgaard, Torben; Takai, Hisamitsu; Zhang, Guoqiang

    2016-01-01

    People spend approximately one third of their life sleeping. Exposure to pollutants in the sleep environment often leads to a variety of adverse health effects, such as development and exacerbation of asthma. Avoiding exposure to these pollutants by providing a sufficient air quality in the sleep environment might be a feasible method to alleviate these health symptoms. We performed full-scale laboratory measurements using a thermal manikin positioned on an experimental bed. Three ventilation settings were tested: with no filtration system operated, use of portable air cleaner and use of a temperature-controlled laminar airflow (TLA) device. The first part of the experiment investigated the air-flow characteristics in the breathing zone. In the second part, particle removal efficiency was estimated. Measured in the breathing zone, the room air cleaner demonstrated high turbulence intensity, high velocity and turbulence diffusivity level, with a particle reduction rate of 52% compared to baseline after 30 minutes. The TLA device delivered a laminar airflow to the breathing zone with a reduction rate of 99.5%. During a periodical duvet lifting mimicking a subject’s movement in bed, the particle concentration was significantly lower with the TLA device compared to the room air cleaner. The TLA device provided a barrier which significantly reduced the introduction of airborne particles into the breathing zone. Further studies should be conducted for the understanding of the transport of resuspended particles between the duvet and the laying body. PMID:27898693

  5. Optimal control of two coupled spinning particles in the Euler-Lagrange picture

    NASA Astrophysics Data System (ADS)

    Delgado-Téllez, M.; Ibort, A.; Rodríguez de la Peña, T.; Salmoni, R.

    2016-01-01

    A family of optimal control problems for a single and two coupled spinning particles in the Euler-Lagrange formalism is discussed. A characteristic of such problems is that the equations controlling the system are implicit and a reduction procedure to deal with them must be carried out. The reduction of the implicit control equations arising in these problems will be discussed in the slightly more general setting of implicit equations defined by invariant one-forms on Lie groups. As an example the first order differential equations describing the extremal solutions of an optimal control problem for a single spinning particle, obtained by using Pontryagin’s Maximum Principle (PMP), will be found and shown to be completely integrable. Then, again using PMP, solutions for the problem of two coupled spinning particles will be characterized as solutions of a system of coupled non-linear matrix differential equations. The reduction of the implicit system will show that the reduced space for them is the product of the space of states for the independent systems, implying the absence of ‘entanglement’ in this instance. Finally, it will be shown that, in the case of identical systems, the degree three matrix polynomial differential equations determined by the optimal feedback law, constitute a completely integrable Hamiltonian system and some of its solutions are described explicitly.

  6. Size Control and Growth Process Study of Au@Cu2O Particles

    NASA Astrophysics Data System (ADS)

    Wang, Yuyuan; Zheng, Min; Liu, Shengnan; Wang, Zuoshan

    2016-09-01

    Au@Cu2O cuboctahedron with gold triangular nanoplate core and Cu2O shell was synthesized by a chemical method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests demonstrated that the as-synthesis samples were consisted of gold triangular nanoplate core and Cu2O shell, and both of them were in good crystallization. The effective size control of the particles could be realized by controlling the amount of Au cores added in the synthetic process and Au@Cu2O particles with different shell thickness could be synthesized. The decrease of Cu2O shell thickness had a great difference in the optical performance, including blue shift of the resonant peaks and enhanced absorption intensity. The growth process from rough sheet structure to cuboctahedron was also explored. The results of photocatalytic degradation experiment showed that Au@Cu2O particles showed much better photocatalytic performance than that of pure Cu2O. The improved photocatalytic property of the Au@Cu2O particles was attributed to the comprehensive effect of the enhanced visible-light absorption and high separation rate of electron-hole pairs.

  7. How the novel integration of electrolysis in tidal flow constructed wetlands intensifies nutrient removal and odor control.

    PubMed

    Ju, Xinxin; Wu, Shubiao; Huang, Xu; Zhang, Yansheng; Dong, Renjie

    2014-10-01

    Intensified nutrient removal and odor control in a novel electrolysis-integrated tidal flow constructed wetland were evaluated. The average removal efficiencies of COD and NH4(+)-N were above 85% and 80% in the two experimental wetlands at influent COD concentration of 300 mg/L and ammonium nitrogen concentration of 60 mg/L regardless of electrolysis integration. Effluent nitrate concentration decreased from 2.5mg/L to 0.5mg/L with the reduction in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2). This result reveals the important role of current intensity in nitrogen transformation. Owing to the ferrous and ferric iron coagulant formed through the electro-dissolution of the iron anode, electrolysis integration not only exerted a positive effect on phosphorus removal but also effectively inhibited sulfide accumulation for odor control. Although electrolysis operation enhanced nutrient removal and promoted the emission of CH4, no significant difference was observed in the microbial communities and abundance of the two experimental wetlands.

  8. Thermo-Mechanical Analysis of Coated Particle Fuel Experiencing a Fast Control Rod Ejection Transient

    SciTech Connect

    Ortensi, J.; Brian Boer; Abderrafi M. Ougouag

    2010-10-01

    A rapid increase of the temperature and the mechanical stress is expected in TRISO coated particle fuel that experiences a fast Total Control Rod Ejection (CRE) transient event. During this event the reactor power in the pebble bed core increases significantly for a short time interval. The power is deposited instantly and locally in the fuel kernel. This could result in a rapid increase of the pressure in the buffer layer of the coated fuel particle and, consequently, in an increase of the coating stresses. These stresses determine the mechanical failure probability of the coatings, which serve as the containment of radioactive fission products in the Pebble Bed Reactor (PBR). A new calculation procedure has been implemented at the Idaho National Laboratory (INL), which analyzes the transient fuel performance behavior of TRISO fuel particles in PBRs. This early capability can easily be extended to prismatic designs, given the availability of neutronic and thermal-fluid solvers. The full-core coupled neutronic and thermal-fluid analysis has been modeled with CYNOD-THERMIX. The temperature fields for the fuel kernel and the particle coatings, as well as the gas pressures in the buffer layer, are calculated with the THETRIS module explicitly during the transient calculation. Results from this module are part of the feedback loop within the neutronic-thermal fluid iterations performed for each time step. The temperature and internal pressure values for each pebble type in each region of the core are then input to the PArticle STress Analysis (PASTA) code, which determines the particle coating stresses and the fraction of failed particles. This paper presents an investigation of a Total Control Rod Ejection (TCRE) incident in the 400 MWth Pebble Bed Modular reactor design using the above described calculation procedure. The transient corresponds to a reactivity insertion of $3 (~2000 pcm) reaching 35 times the nominal power in 0.5 seconds. For each position in the core

  9. An efficient controlled quantum secure direct communication and authentication by using four particle cluster states

    NASA Astrophysics Data System (ADS)

    Nanvakenari, Milad; Houshmand, Monireh

    In this paper, a three-party controlled quantum secure direct communication and authentication (QSDCA) protocol is proposed by using four particle cluster states via a quantum one-time pad and local unitary operations. In the present scheme, only under the permission of the controller, the sender and the receiver can implement secure direct communication successfully. But under any circumstances, Charlie cannot obtain the secret message. Eavesdropping detection and identity authentication are achieved with the help of the previously shared reusable base identity strings of users. This protocol is unconditionally secure in both ideal and practical noisy cases. In one transmission, a qubit of each four particle cluster state is used as controller’s permission and the same qubit with another qubit are used to recover two classical bits of information. In the proposed scheme, the efficiency is improved compared with the previous works.

  10. Development of uranium reference particles for nuclear safeguards and non-proliferation control

    NASA Astrophysics Data System (ADS)

    Kips, Ruth

    In the oversight of the nuclear Non-Proliferation Treaty and as part of the Additional Protocol of the International Atomic Energy Agency, environmental sampling has become an important tool for the detection of non-declared nuclear activities. One extensively developed technique in environmental sampling (ES) makes use of pieces of cotton cloth called swipes to wipe surfaces in and around a nuclear facility. The dust collected on these swipes typically contains micrometer-sized uranium particles with an isotopic composition characteristic for the processes at the inspected facility. Since its implementation in the 1990s, ES has proven to be a very effective tool in the detection of clandestine activities owing to a number of highly sensitive and selective techniques, including secondary ion mass spectrometry and thermal ionisation mass spectrometry. However, considering the potential consequences of the analyses, these measurements need to be subjected to a rigorous quality management system. In a continuous effort to improve the accuracy and detection efficiency of the uranium isotope ratio measurements, uranium particle reference materials are being developed by different research groups. It was concluded however, that the existing methods for the production of particulate reference materials generally do not reproduce the particles recovered from swipe samples. For this reason, we developed the aerosol deposition chamber at the Institute for Reference Materials and Measurements for the production of reference uranium particles that are representative of the particles collected at enrichment facilities. This method is based on the controlled hydrolysis of milligram amounts of uranium hexafluoride with a certified uranium isotopic composition. After optimization of the experimental set-up, the particles produced by the aerosol deposition chamber were characterized by scanning electron microscopy, transmission electron microscopy, micro-Raman spectroscopy and

  11. NEW ASPECTS OF A LID-REMOVAL MECHANISM IN THE ONSET OF AN ERUPTION SEQUENCE THAT PRODUCED A LARGE SOLAR ENERGETIC PARTICLE (SEP) EVENT

    SciTech Connect

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.; Knox, Javon M. E-mail: ron.moore@nasa.gov

    2014-06-20

    We examine a sequence of two ejective eruptions from a single active region on 2012 January 23, using magnetograms and EUV images from the Solar Dynamics Observatory's (SDO) Helioseismic and Magnetic Imager (HMI) and Atmospheric and Imaging Assembly (AIA), and EUV images from STEREO/EUVI. This sequence produced two coronal mass ejections (CMEs) and a strong solar energetic particle event (SEP); here we focus on the magnetic onset of this important space weather episode. Cheng et al. showed that the first eruption's ({sup E}ruption 1{sup )} flux rope was apparent only in ''hotter'' AIA channels, and that it removed overlying field that allowed the second eruption ({sup E}ruption 2{sup )} to begin via ideal MHD instability; here we say that Eruption 2 began via a ''lid removal'' mechanism. We show that during Eruption 1's onset, its flux rope underwent a ''tether weakening'' (TW) reconnection with field that arched from the eruption-source active region to an adjacent active region. Standard flare loops from Eruption 1 developed over Eruption 2's flux rope and enclosed filament, but these overarching new loops were unable to confine that flux rope/filament. Eruption 1's flare loops, from both TW reconnection and standard-flare-model internal reconnection, were much cooler than Eruption 2's flare loops (GOES thermal temperatures of ∼7.5 MK and 9 MK, compared to ∼14 MK). The corresponding three sequential GOES flares were, respectively, due to TW reconnection plus earlier phase Eruption 1 tether-cutting reconnection, Eruption 1 later-phase tether-cutting reconnection, and Eruption 2 tether-cutting reconnection.

  12. Precision control of high temperature furnaces using an auxiliary power supply and charged particle current flow

    DOEpatents

    Pollock, G.G.

    1997-01-28

    Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. 5 figs.

  13. Solid oxide fuel cell cathode infiltrate particle size control and oxygen surface exchange resistance determination

    NASA Astrophysics Data System (ADS)

    Burye, Theodore E.

    Over the past decade, nano-sized Mixed Ionic Electronic Conducting (MIEC) -- micro-sized Ionic Conducting (IC) composite cathodes produced by the infiltration method have received much attention in the literature due to their low polarization resistance (RP) at intermediate (500-700°C) operating temperatures. Small infiltrated MIEC oxide nano-particle size and low intrinsic MIEC oxygen surface exchange resistance (Rs) have been two critical factors allowing these Nano-Micro-Composite Cathodes (NMCCs) to achieve high performance and/or low temperature operation. Unfortunately, previous studies have not found a reliable method to control or reduce infiltrated nano-particle size. In addition, controversy exists on the best MIEC infiltrate composition because: 1) Rs measurements on infiltrated MIEC particles are presently unavailable in the literature, and 2) bulk and thin film Rs measurements on nominally identical MIEC compositions often vary by up to 3 orders of magnitude. Here, two processing techniques, precursor nitrate solution desiccation and ceria oxide pre-infiltration, were developed to systematically produce a reduction in the average La0.6Sr0.4Co0.8Fe 0.2O3-delta (LSCF) infiltrated nano-particle size from 50 nm to 22 nm. This particle size reduction reduced the SOFC operating temperature, (defined as the temperature where RP=0.1 Ocm 2) from 650°C to 540°C. In addition, Rs values for infiltrated MIEC particles were determined for the first time through finite element modeling calculations on 3D Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) reconstructions of electrochemically characterized infiltrated electrodes.

  14. Controlling the Growth of Future LEO Debris Populations with Active Debris Removal

    NASA Technical Reports Server (NTRS)

    Liou, J.-C.; Johnson, N. L.; Hill, N. M.

    2008-01-01

    Active debris removal (ADR) was suggested as a potential means to remediate the low Earth orbit (LEO) debris environment as early as the 1980s. The reasons ADR has not become practical are due to its technical difficulties and the high cost associated with the approach. However, as the LEO debris populations continue to increase, ADR may be the only option to preserve the near-Earth environment for future generations. An initial study was completed in 2007 to demonstrate that a simple ADR target selection criterion could be developed to reduce the future debris population growth. The present paper summarizes a comprehensive study based on more realistic simulation scenarios, including fragments generated from the 2007 Fengyun-1C event, mitigation measures, and other target selection options. The simulations were based on the NASA long-term orbital debris projection model, LEGEND. A scenario, where at the end of mission lifetimes, spacecraft and upper stages were moved to 25-year decay orbits, was adopted as the baseline environment for comparison. Different annual removal rates and different ADR target selection criteria were tested, and the resulting 200-year future environment projections were compared with the baseline scenario. Results of this parametric study indicate that (1) an effective removal strategy can be developed based on the mass and collision probability of each object as the selection criterion, and (2) the LEO environment can be stabilized in the next 200 years with an ADR removal rate of five objects per year.

  15. Simulation of sediment transport due to dam removal and control of morphological changes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents two case studies of post dam removal sedimentation in the United States. Two different one-dimensional channel evolution simulation models were used: CCHE1D and CONCEPTS, respectively. The first case is the application of CCHE1D to assess the long-term (up to 10 years) morphologi...

  16. Control mechanisms of soil particle size on the quality of soil organic matter

    NASA Astrophysics Data System (ADS)

    Coplin, A.; Faiia, A. M.; Aho, K.; Kelson, S.; Virginia, R. A.; Xu, X.; Feng, X.

    2009-12-01

    The quality of soil organic matter (SOM), which measures the resistance of SOM to biological degradation, is an important factor controlling soil turnover rates and soil carbon sequestration. The main goals of this study were to evaluate how soil particle size affects the quality of SOM, the mechanism responsible for the relationship between particle size and SOM quality, and the potential impact of the relationship on carbon dynamics and sequestration. We used stable C and N isotopic ratios (δ13C and δ15N) to measure the relative quality of nine physically separated particle size fractions from soil collected in Hanover, NH, Suffolk County, Long Island, NY and the northeastern coast of Newfoundland mainland province (formerly Labrador), Canada. Radiocarbon dating, X-ray diffraction (XRD), scanning electron microscopy (SEM) imagery and X-ray microanalysis were used to investigate the mechanism of the observed quality-particle size relationship. At a given depth, Hanover soil yielded a strong nonlinear relationship between δ13C or δ15N and particle size, where low isotopic ratios were associated with large and small size fractions, while relatively high ratios with intermediate particles. When combined with the radiocarbon results, it shows that clay particle fractions contain high quality SOM that is disproportional to the radiocarbon age. This result suggests that SOM associated with clay-sized particles are physically protected from microbial decomposition, such that stable isotope ratios cease to change after aggregation while C-14 continues to decay. Both XRD and SEM studies confirmed the role of clay minerals (particularly vermiculite) for mineral protection of SOM. We explain the nonlinear relationship between δ13C or δ15N and particle size to be a result of the competing processes that cause reducing particle size of SOM with increasing the degree of degradation, and increasing mineral protection by aggregate structures with decreasing particle size

  17. Control of aerosol contaminants in indoor air: combining the particle concentration reduction with microbial inactivation.

    PubMed

    Grinshpun, Sergey A; Adhikari, Atin; Honda, Takeshi; Kim, Ki Youn; Toivola, Mika; Rao, K S Ramchander; Reponen, Tiina

    2007-01-15

    An indoor air purification technique, which combines unipolar ion emission and photocatalytic oxidation (promoted by a specially designed RCI cell), was investigated in two test chambers, 2.75 m3 and 24.3 m3, using nonbiological and biological challenge aerosols. The reduction in particle concentration was measured size selectively in real-time, and the Air Cleaning Factor and the Clean Air Delivery Rate (CADR) were determined. While testing with virions and bacteria, bioaerosol samples were collected and analyzed, and the microorganism survival rate was determined as a function of exposure time. We observed that the aerosol concentration decreased approximately 10 to approximately 100 times more rapidly when the purifier operated as compared to the natural decay. The data suggest that the tested portable unit operating in approximately 25 m3 non-ventilated room is capable to provide CADR-values more than twice as great than the conventional closed-loop HVAC system with a rating 8 filter. The particle removal occurred due to unipolar ion emission, while the inactivation of viable airborne microorganisms was associated with photocatalytic oxidation. Approximately 90% of initially viable MS2 viruses were inactivated resulting from 10 to 60 min exposure to the photocatalytic oxidation. Approximately 75% of viable B. subtilis spores were inactivated in 10 min, and about 90% or greater after 30 min. The biological and chemical mechanisms that led to the inactivation of stress-resistant airborne viruses and bacterial spores were reviewed.

  18. Controlled incremental filtration: a simplified approach to design and fabrication of high-throughput microfluidic devices for selective enrichment of particles.

    PubMed

    Gifford, Sean C; Spillane, Angela M; Vignes, Seth M; Shevkoplyas, Sergey S

    2014-12-07

    The number of microfluidic strategies aimed at separating particles or cells of a specific size within a continuous flow system continues to grow. The wide array of biomedical and other applications that would benefit from successful development of such technology has motivated the extensive research in this area over the past 15 years. However, despite promising advancements in microfabrication capabilities, a versatile approach that is suitable for a large range of particle sizes and high levels of enrichment, with a volumetric throughput sufficient for large-scale applications, has yet to emerge. Here we describe a straightforward method that enables the rapid design of microfluidic devices that are capable of enriching/removing particles within a complex aqueous mixture, with an unprecedented range of potential cutoff diameter (below 1 μm to above 100 μm) and an easily scalable degree of enrichment/filtration (up to 10-fold and well beyond). A simplified model of a new approach to crossflow filtration - controlled incremental filtration - was developed and validated for its ability to generate microfluidic devices that efficiently separate particles on the order of 1-10 μm, with throughputs of tens of μL min(-1), without the use of a pump. Precise control of the amount of fluid incrementally diverted at each filtration "gap" of the device allows for the gap size (~20 μm) to be much larger than the particles of interest, while the simplicity of the model allows for many thousands of these filtration points to be readily incorporated into a desired device design. This new approach should enable truly high-throughput microfluidic particle-separation devices to be generated, even by users only minimally experienced in fluid mechanics and microfabrication techniques.

  19. Retrospective analysis of the clinical response of palmoplantar pustulosis after dental infection control and dental metal removal.

    PubMed

    Kouno, Michiyoshi; Nishiyama, Akihiro; Minabe, Masaki; Iguchi, Naohiko; Ukichi, Kenichiro; Nomura, Takeshi; Katakura, Akira; Takahashi, Shinichi

    2017-02-02

    Both metal allergy and dental focal infection have been considered as causative factors for palmoplantar pustulosis, and several case reports described that the skin lesions were ameliorated after dental metal removal or dental infection control. However, limited data are available to evaluate the association of these factors with disease severity of palmoplantar pustulosis. This study is designed to analyze the clinical outcome of 85 palmoplantar pustulosis patients after dental infection control (n = 70), tonsillectomy (n = 6) and dental metal removal (n = 9). More than half of the patients (63%, 44/70) showed positive clinical outcome after dental infection control. The skin lesions of all patients with tonsillitis were improved after tonsillectomy (100%, 6/6). On the other hand, one-third of patients (33%, 3/9) showed positive response after dental metal removal. These results suggest that focal infection is more closely associated with palmoplantar pustulosis than dental metal allergy. According to our findings, palmoplantar pustulosis patients should be preferentially examined for focal infections.

  20. Controlling the structure and dynamics of magnetoresponsive particle suspensions for enhanced transport phenomena

    NASA Astrophysics Data System (ADS)

    Solis, Kyle J.

    The work contained herein describes the use of various magnetic fields to control the structure and dynamics of magnetic particle suspensions, with the practical aim of enhancing momentum, heat, and mass transport. The magnetic fields are often multiaxial and can consist of up to three orthogonal components that may be either static (dc), time-dependent (ac), or some combination thereof. The magnetic particles are composed of a ferromagnetic material---such as iron, nickel, cobalt, or Permalloy---and can exist in a variety of shapes, including spheres, platelets, and rods. The shape of the particles is particularly important, as this can determine the type of behavior the suspension exhibits and can strongly affect the efficacy of various transport properties. The continuous phase can be almost any fluid so long as it possesses a viscosity that allows the particles to orient and aggregate in response to the applied field. Additionally, if the liquid is polymerizable (e.g., an epoxy system), then composite materials with particular, field-directed particle assemblies can be created. Given the many combinations of various particles, suspending fluids, and magnetic fields, a vast array of behavior is possible: the formation of anisotropic particle structures for directed heat transport for use as advanced thermal interface materials; the stimulation of emergent dynamics in platelet suspensions, which give rise to field-controllable flow lattices; and the creation of vortex fluids that possess a uniform torque density, enabling such strange behaviors as active wetting, a negative viscosity and striking biomimetic dynamics. Because the applied fields used to produce many of these phenomena are uniform and modest in strength, such adaptive fluids open up the possibility of tuning the degree of mixing or heat/mass transfer for specific operating conditions in a number of processes, ranging from the microscale to the industrial scale. Moreover, the very nature of magnetism

  1. Dissipative dynamics of a particle in a vibrating periodic potential: Chaos and control

    NASA Astrophysics Data System (ADS)

    Chacón, R.; Martínez, P. J.; Martínez, J. A.

    2015-12-01

    The dissipative chaotic dynamics of a particle subjected to a horizontally vibrating periodic potential is characterized theoretically and confirmed numerically in the case of an external chaos-controlling periodic excitation also acting on the particle. Theoretical predictions concerning the chaotic threshold in parameter space are deduced from the application of Melnikov's method that fully determine the chaos-control scenario. Also, the structure of diverse regularization regions in parameter space is explained theoretically with the aid of an energy analysis. It was found that the phase difference between the two periodic excitations involved plays a crucial role in the chaos-control scenario, with the particular feature that its optimal value depends upon the ratio between the damping coefficient and the excitation frequency. This constitutes a genuine feature of the chaos-control scenario associated with nonsteady potentials which is in contrast to the case of steady potentials. Additionally, we demonstrate the robustness of the chaos-control scenario against the presence of low-intensity Gaussian noise and reshaping of chaos-suppressing excitations.

  2. Dissipative dynamics of a particle in a vibrating periodic potential: Chaos and control.

    PubMed

    Chacón, R; Martínez, P J; Martínez, J A

    2015-12-01

    The dissipative chaotic dynamics of a particle subjected to a horizontally vibrating periodic potential is characterized theoretically and confirmed numerically in the case of an external chaos-controlling periodic excitation also acting on the particle. Theoretical predictions concerning the chaotic threshold in parameter space are deduced from the application of Melnikov's method that fully determine the chaos-control scenario. Also, the structure of diverse regularization regions in parameter space is explained theoretically with the aid of an energy analysis. It was found that the phase difference between the two periodic excitations involved plays a crucial role in the chaos-control scenario, with the particular feature that its optimal value depends upon the ratio between the damping coefficient and the excitation frequency. This constitutes a genuine feature of the chaos-control scenario associated with nonsteady potentials which is in contrast to the case of steady potentials. Additionally, we demonstrate the robustness of the chaos-control scenario against the presence of low-intensity Gaussian noise and reshaping of chaos-suppressing excitations.

  3. A micromanipulation particle tester for agglomeration contact mechanism studies in a controlled environment

    NASA Astrophysics Data System (ADS)

    Haider, C. I.; Althaus, T.; Niederreiter, G.; Hounslow, M. J.; Palzer, S.; Salman, A. D.

    2012-10-01

    Pressure agglomeration of powders is widely applied in various industries and an increasing interest lies in the identification and description of contact mechanisms between particles, which are responsible for the compaction product properties. In this paper, the design and development of a novel micromanipulation particle tester (MPT) is presented. This device makes it possible to measure the deformation kinetics and resulting adhesion of two individual particles in contact under load, which are strongly influenced by the applied process conditions. The MPT set-up is, therefore, designed to offer a unique control over the process conditions most relevant to the compaction of powders: external stress, dwell or holding time at constant deformation, compression velocity as well as relative humidity and temperature determining the physical state and mechanical characteristics of hygrosensitive amorphous particles. The latter are often part of powder formulations, e.g. in the food industry, and have been used for force and contact-zone development studies with the MPT. The experimental results on the microscale level will deliver valuable quantitative information for an improved tailoring of pressure agglomeration process conditions of bulk solids.

  4. Potential of kaolin-based particle film barriers for Formosan subterranean termite (Isoptera: Rhinotermitidae) control

    USGS Publications Warehouse

    Wiltz, B.A.; Woodson, W.D.; Puterka, G.J.

    2010-01-01

    Effects of three particle film products on Formosan subterranean termites, Coptotermes formosanus Shiraki, were evaluated in feeding, tunneling, and contact assays. The particle films, hydrophobic M96-018 and hydrophilic Surround and Surround WP are based on the inert clay mineral kaolin. In 2-week long no-choice feeding tests, significant mortality occurred only with M96-018-coated wood. When a choice was provided, M96-018 and Surround were consumed at higher rates than untreated wood. Surround WP did not differ from controls in either test. In the tunneling assay termites were given the option of crossing a kaolin-sand mixture to reach an alternate food source. After 3-weeks, rates of 1% and 5% M96-018 provided an effective barrier to Formosan termite tunneling, while termites were not stopped by rates as high as 20% Surround and Surround WP. Dust treatments of all three formulations caused significant increases in mortality within 24 h, with mortality rates ranging from 72.0 - 97.3% within 72 h of treatment. The particle films were most effective when moisture levels were low, suggesting that desiccation was the mechanism for mortality. All particle films showed potential for use in above ground applications while hydrophobic M06-018 has the most potential as a soil barrier to subterranean termites.

  5. Replicating Viral Particles and other Shape-controlled, Functional Particles for Targeted Delivery Applications Using Nano-molding Techniques

    DTIC Science & Technology

    2007-10-23

    are not toxic to B6 mice, don’t interfere with a PnP induced humeral response and don’t sequester themselves in a compartment that is...aminoethylmethacrylate incorporated (see Figure 6). We have reacted those amine groups on the surface with 2,4,6-trinitrobenzene 1-sulfonic acid ( TNBS ...solution containing amine-functionalized PRINT particles with TNBS (Figure 7). NP (nitrophenol)-decorated PRINT particles (conjugated to the surface

  6. Study on a discrete-time dynamic control model to enhance nitrogen removal with fluctuation of influent in oxidation ditches.

    PubMed

    Liu, Yanchen; Shi, Hanchang; Shi, Huiming; Wang, Zhiqiang

    2010-10-01

    The aim of study was proposed a new control model feasible on-line implemented by Programmable Logic Controller (PLC) to enhance nitrogen removal against the fluctuation of influent in Carrousel oxidation ditch. The discrete-time control model was established by confirmation model of operational conditions based on a expert access, which was obtained by a simulation using Activated Sludge Model 2-D (ASM2-D) and Computation Fluid Dynamics (CFD), and discrete-time control model to switch between different operational stages. A full-scale example is provided to demonstrate the feasibility of the proposed operation and the procedure of the control design. The effluent quality was substantially improved, to the extent that it met the new wastewater discharge standards of NH(3)-N<5mg/L and TN<15 mg/L enacted in China throughout a one-day period with fluctuation of influent.

  7. Sliding mode control of dissolved oxygen in an integrated nitrogen removal process in a sequencing batch reactor (SBR).

    PubMed

    Muñoz, C; Young, H; Antileo, C; Bornhardt, C

    2009-01-01

    This paper presents a sliding mode controller (SMC) for dissolved oxygen (DO) in an integrated nitrogen removal process carried out in a suspended biomass sequencing batch reactor (SBR). The SMC performance was compared against an auto-tuning PI controller with parameters adjusted at the beginning of the batch cycle. A method for cancelling the slow DO sensor dynamics was implemented by using a first order model of the sensor. Tests in a lab-scale reactor showed that the SMC offers a better disturbance rejection capability than the auto-tuning PI controller, furthermore providing reasonable performance in a wide range of operation. Thus, SMC becomes an effective robust nonlinear tool to the DO control in this process, being also simple from a computational point of view, allowing its implementation in devices such as industrial programmable logic controllers (PLCs).

  8. Adsorption kinetics of magnetic biochar derived from peanut hull on removal of Cr (VI) from aqueous solution: Effects of production conditions and particle size.

    PubMed

    Han, Yitong; Cao, Xi; Ouyang, Xin; Sohi, Saran P; Chen, Jiawei

    2016-02-01

    Magnetic biochar was made from peanut hull biomass using iron chloride in a simplified aqueous phase approach and pyrolysis at alternative peak temperatures (450-650 °C). Magnetic biochar showed an extreme capacity for adsorption of hexavalent chromium Cr (VI) from aqueous solution, which was 1-2 orders of magnitude higher compared to standard (non-magnetic) biochar from the same feedstock. Adsorption increased with pyrolysis temperature peaking at 77,542 mg kg(-1) in the sample pyrolysed at 650 °C. In contrast to magnetic biochar, the low adsorption capacity of standard biochar decreased with increasing pyrolysis temperature. The fine particle size of magnetic biochar and low aqueous pH were also important for adsorption. Surfaces of products from batch adsorption experiments were characterized by scanning electron microscopy, energy-dispersive X-ray analysis, X-ray diffraction, X-ray photoelectron spectroscopy and vibrating sample magnetometer. This revealed that γ-Fe2O3 was crucial to the properties (adsorbance and magnetism) of magnetic biochar. The removal mechanism was the Cr (VI) electrostatic attracted on protonated -OH on γ-Fe2O3 surface and it could be desorbed by alkaline solution. Findings suggest that pyrolysis has potential to create effective, magnetically recoverable adsorbents relevant to environmental application.

  9. Preparation of aqueous colloidal mesostructured and mesoporous silica nanoparticles with controlled particle size in a very wide range from 20 nm to 700 nm

    NASA Astrophysics Data System (ADS)

    Yamada, Hironori; Urata, Chihiro; Ujiie, Hiroto; Yamauchi, Yusuke; Kuroda, Kazuyuki

    2013-06-01

    Particle size control of colloidal mesoporous silica nanoparticles (CMPS) in a very wide range is quite significant for the design of CMPS toward various applications, such as catalysis and drug delivery. Various types of CMPS and their precursors (colloidal mesostructured silica nanoparticles (CMSS)) with different particle sizes (ca. 20-700 nm) were newly prepared from tetraalkoxysilanes with different alkoxy groups (Si(OR)4, R = Me, Et, Pr, and Bu) in the presence of alcohols (R'OH, R' = Me, Et, Pr, and Bu) as additives. CMSS with larger particle size were obtained by using tetrabutoxysilane (TBOS) and by increasing the amount of BuOH, which is explained by both the difference in the hydrolysis rates of tetraalkoxysilanes themselves and the effect of added alcohols on the hydrolysis rates of tetraalkoxysilanes. Larger amounts of alcohols with longer alkyl chains decrease the hydrolysis rates of tetraalkoxysilanes and the subsequent formation rates of silica species. Thus, the preferential particle growth of CMSS to nucleation occurs, and larger CMSS are formed. Highly dispersed CMPS were prepared by the removal of surfactants of CMSS by dialysis which can lead to the preparation of CMPS without aggregation. Therefore, the particle size control through the tuning of the hydrolysis rate of tetraalkoxysilanes can be conducted by a one-pot and easy approach. Even larger CMPS (ca. 700 nm in size) show relatively high dispersibility. This dispersibility will surely contribute to the design of materials both retaining nanoscale characteristics and avoiding various nanorisks.Particle size control of colloidal mesoporous silica nanoparticles (CMPS) in a very wide range is quite significant for the design of CMPS toward various applications, such as catalysis and drug delivery. Various types of CMPS and their precursors (colloidal mesostructured silica nanoparticles (CMSS)) with different particle sizes (ca. 20-700 nm) were newly prepared from tetraalkoxysilanes with

  10. Nondestructive and Destructive Examination Studies on Removed-from-Service Control Rod Drive Mechanism Penetrations

    SciTech Connect

    Cumblidge, Stephen E.; Crawford, Susan L.; Doctor, Steven R.; Seffens, Rob J.; Schuster, George J.; Toloczko, Mychailo B.; Harris, Robert V.; Bruemmer, Stephen M.

    2007-06-07

    Studies conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, focused on assessing the effectiveness of nondestructive examination (NDE) techniques for inspecting control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objectives of this work are to provide information to the U.S. Nuclear Regulatory Commission (NRC) on the effectiveness of NDE methods as related to the in-service inspection of CRDM nozzles and J-groove weldments and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. Two CRDM assemblies were removed from service, decontaminated, and then used in a series of NDE and destructive examination (DE) measurements; this report addresses the following questions: 1) What did each NDE technique detect? 2) What did each NDE technique miss? 3) How accurately did each NDE technique characterize the detected flaws? 4) Why did the NDE techniques perform or not perform? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. This report focuses on a CRDM assembly that contained suspected PWSCC, based on in-service inspection data and through-wall leakage. The NDE measurements used to examine the CRDM assembly followed standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. These techniques included eddy current testing (ET), time-of-flight diffraction ultrasound, and penetrant testing. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assembly with particular emphasis on inspecting the J-groove weld and buttering. These techniques included volumetric ultrasonic inspection of the J-groove weld metal and visual testing via replicant material of the J-groove weld. The results from these NDE studies were used to

  11. Optimal control for a parallel hybrid hydraulic excavator using particle swarm optimization.

    PubMed

    Wang, Dong-yun; Guan, Chen

    2013-01-01

    Optimal control using particle swarm optimization (PSO) is put forward in a parallel hybrid hydraulic excavator (PHHE). A power-train mathematical model of PHHE is illustrated along with the analysis of components' parameters. Then, the optimal control problem is addressed, and PSO algorithm is introduced to deal with this nonlinear optimal problem which contains lots of inequality/equality constraints. Then, the comparisons between the optimal control and rule-based one are made, and the results show that hybrids with the optimal control would increase fuel economy. Although PSO algorithm is off-line optimization, still it would bring performance benchmark for PHHE and also help have a deep insight into hybrid excavators.

  12. Development of a Scalable Process Control System for Chemical Soil Washing to Remove Uranyl Oxide

    DTIC Science & Technology

    2015-05-01

    is reactive, oxidizing once it has been deposited into soil. The recovery process needs a variety of measurement systems for precisely locating the...medical imaging material, etc.), toxic or hazardous materials such as pesticides or asbestos , consumer products such as refrigerators or...2012), the soil fines remain contaminated by tightly bound DU oxides. The leaching system removes uranium from these soil fines and deposits the

  13. Improvement of ammonia removal in activated sludge process with feedforward-feedback aeration controllers.

    PubMed

    Vrecko, Darko; Hvala, Nadja; Stare, Aljaz; Burica, Olga; Strazar, Marjeta; Levstek, Meta; Cerar, Peter; Podbevsek, Sebastjan

    2006-01-01

    In the paper three linear aeration controllers that can be easily implemented are presented and evaluated on the activated sludge process pilot plant. Controllers differ according to the information that is used about the process, which can be oxygen in the last aerobic reactor, ammonia in the last aerobic reactor and ammonia in the influent. The aeration controllers that are addressed are: oxygen cascade PI controller, ammonia cascade PI controller and ammonia feedforward-cascade PI controller. Experiments show that, in comparison with the oxygen cascade PI controller, the ammonia cascade PI controller allows better control of effluent ammonia and airflow savings of around 23%, while the ammonia feedforward-cascade PI controller gives the best reduction of ammonia peaks and can save up to 45% of the airflow.

  14. Clinical study to assess the stain removal efficacy of two tartar control dentifrices and a low abrasive dentifrice.

    PubMed

    Yankell, S L; Emling, R C; Prencipe, M; Rustogi, K; Volpe, A R

    1994-01-01

    Significant differences in stain removal have been demonstrated in a laboratory study comparing two tartar control dentifrices: Platinum, containing 1.3% soluble pyrophosphate and 1.5% of a copolymer, and Crest Tartar Control, containing 5% soluble pyrophosphate. The purpose of this clinical study was to evaluate the same tartar control dentifrices, and a low abrasive dentifrice for their ability to reduce Peridex-induced stain. Eighty-five subjects were given Peridex (0.12% chlorhexidine digluconate) and a low abrasive dentifrice for 4 weeks. The 76 subjects with sufficient stain were stratified using the Lobene index on buccal and lingual surfaces of anterior teeth, and randomly assigned one of the three dentifrices for 8 weeks. At the end of the study, total stain evaluations were significantly lower in the Platinum dentifrice group (mean 0.84) compared to both Crest Tartar Control dentifrice (1.08) and the low abrasive dentifrice (1.09) at p<0.05 by ANOVA. In this 8-week clinical study, Platinum dentifrice was significantly more effective than Crest Tartar Control dentifrice or a low abrasive dentifrice in reducing Peridex-induced stain, and this finding correlates well with laboratory data on removal of tea and coffee stain.

  15. Applying real-time control for achieving nitrogen removal via nitrite in a lab-scale CAST system.

    PubMed

    Wang, Shaopo; Yu, Jingjie; Wei, Tianlan; Chi, Yongzhi; Sun, Liping; Peng, Yongzhen

    2012-06-01

    In this study, a bench-scale Cyclic Activated Sludge Technology (CAST) reactor (72?L), fed with domestic sewage, was operated in alternating anoxi-aerobic operation mode to investigate the feasibility of achieving short-cut nitrification and denitrification with a real-time control strategy. An online system for controlling the length of the aeration and stirring phases was implemented, based on pH and oxidation-reduction potential signals, to switch between aerobic and anoxic sequences. Results show that the real-time control strategy was successful in achieving a stable nitrogen removal performance. Furthermore, short-cut nitrification can be achieved by controlling aeration length under the modified real-time control strategy. Gradually reducing the energy supply for nitrite-oxidizing bacteria caused the limitation of their growth and, finally, their elimination. When short-cut nitrification was obtained, the nitrite pathway became the primary way for nitrogen removal, and aeration duration was reduced by 28.4%.

  16. Legal requirements and guidelines for the control of harmful laser generated particles, vapours and gases

    NASA Astrophysics Data System (ADS)

    Horsey, John

    2015-07-01

    This paper is a review of the Health and Safety laws and guidelines relating to laser generated emissions into the workplace and outside environment with emphasis on the differences between legal requirements and guideline advice. The types and nature of contaminants released by various laser processes (i.e. cutting, coding, engraving, marking etc) are discussed, together with the best methods for controlling them to within legal exposure limits. A brief description of the main extract air filtration techniques, including the principles of particulate removal and the action of activated carbon for gas/vapour/odour filtration, is given.

  17. Facile synthesis of methotrexate intercalated layered double hydroxides: particle control, structure and bioassay explore.

    PubMed

    Tian, De-Ying; Liu, Zhen-Lei; Li, Shu-Ping; Li, Xiao-Dong

    2014-12-01

    To study the influence of particle size on drug efficacy and other properties, a series of methotrexate intercalated layered double hydroxides (MTX/LDHs) were synthesized through the traditional coprecipitation method, using a mixture of water and polyethylene glycol (PEG-400) as the solvent. To adjust the particle size of MTX/LDHs, the dropping way, the volume ratio of water to PEG-400 and different hydrothermal treatment time changed accordingly, and the results indicate that the particle size can be controlled between 90 and 140 nm. Elemental C/H/N and inductive coupled plasma (ICP) analysis indicated that different synthesis conditions almost have no effect on the compositions of the nanohybrids. X-ray diffraction (XRD) patterns manifested the successful intercalation of MTX anions into the LDH interlayers, and it's also found out that different volume ratios of water to PEG-400 and variable dropping way can affect the crystallinity of the final samples, i.e., the volume ratio of 3:1 and pH decreasing are proved to be optimum conditions. Furthermore, both antiparallel monolayer and bilayers adopting different orientations are suggested for four samples from XRD results. Fourier transform infrared spectroscopy (FTIR) investigations proved the coexistence of CO3(2-) and MTX anions in the interlayer of the nanohybrids. MTX/LDH particles exhibited hexagonal platelet morphology with round corner and different dropping ways can affect the morphology greatly. Moreover, a DSC study indicated that longer time treatment can weaken the bond between the MTX anions and LDH layers. The kinetic release profiles told us that larger MTX/LDH particles have enhanced the ability of LDH layers to protect interlayer molecules. At last, the bioassay study indicated that the nanohybrids with larger diameters have higher tumor suppression efficiency.

  18. ALARA Controls and the Radiological Lessons Learned During the Uranium Fuel Removal Projects at the Molten Salt Reactor Experiment

    SciTech Connect

    Gilliam, B. J.; Chapman, J. A.; Jugan, M. R.

    2002-02-26

    The removal of uranium-233 (233 U) from the auxiliary charcoal bed (ACB) of the Molten Salt Reactor Experiment (MSRE), performed from January through May 2001, created both unique radiological challenges and widely-applicable lessons learned. In addition to the criticality concerns and alpha contamination, 233U has an associated intense gamma photon from the cocontaminant uranium-232 (232U) decaying to thallium-208 (208Tl). Therefore, rigorous contamination controls and significant shielding were implemented. Extensive, timed mock-up training was also imperative to minimize individual and collective personnel exposures. Back-up shielding and containment techniques (that had been previously developed for defense in depth) were used successfully to control significant, changed conditions. Additional controls were placed on tests and on recovery designs to assure a higher level of safety throughout the removal operations. This paper delineates the manner in which each difficulty was solved, while relating the relevance of the results and the methodology to other projects with high dose-rate, highly-contaminated ionizing radiation hazards. Because of the distinctive features of and current interest in molten salt technology, a brief overview is provided. Also presented is the detailed, practical application of radiological controls integrated into, rather than added after, each evolution of the project--thus demonstrating the broad-based benefits of radiological engineering and ALARA reviews. The resolution of the serious contamination-control problems caused by unexpected uranium hexafluoride (UF6) gaseous diffusion is also explicated. Several tables and figures document the preparations, equipment and operations. A comparison of the pre-job dose calculations for the various functions of the uranium deposit removal (UDR) and the post-job dose-rate data are included in the conclusion.

  19. Controlled isotropic or anisotropic nanoscale growth of coordination polymers: formation of hybrid coordination polymer particles.

    PubMed

    Lee, Hee Jung; Cho, Yea Jin; Cho, Won; Oh, Moonhyun

    2013-01-22

    The ability to fabricate multicompositional hybrid materials in a precise and controlled manner is one of the primary goals of modern materials science research. In addition, an understanding of the phenomena associated with the systematic growth of one material on another can facilitate the evolution of multifunctional hybrid materials. Here, we demonstrate precise manipulation of the isotropic and/or anisotropic nanoscale growth of various coordination polymers (CPs) to obtain heterocompositional hybrid coordination polymer particles. Chemical composition analyses conducted at every growth step reveal the formation of accurately assembled hybrid nanoscale CPs, and microscopy images are used to examine the morphology of the particles and visualize the hybrid structures. The dissimilar growth behavior, that is, growth in an isotropic or anisotropic fashion, is found to be dependent on the size of the metal ions involved within the CPs.

  20. Mass-flow-rate-controlled fluid flow in nanochannels by particle insertion and deletion

    NASA Astrophysics Data System (ADS)

    Barclay, Paul L.; Lukes, Jennifer R.

    2016-12-01

    A nonequilibrium molecular dynamics method to induce fluid flow in nanochannels, the insertion-deletion method (IDM), is introduced. IDM inserts and deletes particles within distinct regions in the domain, creating locally high and low pressures. The benefits of IDM are that it directly controls a physically meaningful quantity, the mass flow rate, allows for pressure and density gradients to develop in the direction of flow, and permits treatment of complex aperiodic geometries. Validation of IDM is performed, yielding good agreement with the analytical solution of Poiseuille flow in a planar channel. Comparison of IDM to existing methods indicates that it is best suited for gases, both because it intrinsically accounts for compressibility effects on the flow and because the computational cost of particle insertion is lowest for low-density fluids.

  1. Artificial neural network and particle swarm optimization for removal of methyl orange by gold nanoparticles loaded on activated carbon and Tamarisk

    NASA Astrophysics Data System (ADS)

    Ghaedi, M.; Ghaedi, A. M.; Ansari, A.; Mohammadi, F.; Vafaei, A.

    2014-11-01

    The influence of variables, namely initial dye concentration, adsorbent dosage (g), stirrer speed (rpm) and contact time (min) on the removal of methyl orange (MO) by gold nanoparticles loaded on activated carbon (Au-NP-AC) and Tamarisk were investigated using multiple linear regression (MLR) and artificial neural network (ANN) and the variables were optimized by partial swarm optimization (PSO). Comparison of the results achieved using proposed models, showed the ANN model was better than the MLR model for prediction of methyl orange removal using Au-NP-AC and Tamarisk. Using the optimal ANN model the coefficient of determination (R2) for the test data set were 0.958 and 0.989; mean squared error (MSE) values were 0.00082 and 0.0006 for Au-NP-AC and Tamarisk adsorbent, respectively. In this study a novel and green approach were reported for the synthesis of gold nanoparticle and activated carbon by Tamarisk. This material was characterized using different techniques such as SEM, TEM, XRD and BET. The usability of Au-NP-AC and activated carbon (AC) Tamarisk for the methyl orange from aqueous solutions was investigated. The effect of variables such as pH, initial dye concentration, adsorbent dosage (g) and contact time (min) on methyl orange removal were studied. Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show the suitability and applicability of the Langmuir model. Kinetic models such as pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models indicate that the second-order equation and intraparticle diffusion models control the kinetic of the adsorption process. The small amount of proposed Au-NP-AC and activated carbon (0.015 g and 0.75 g) is applicable for successful removal of methyl orange (>98%) in short time (20 min for Au-NP-AC and 45 min for Tamarisk-AC) with high adsorption capacity 161 mg g-1 for Au-NP-AC and 3.84 mg g-1 for Tamarisk-AC.

  2. Artificial neural network and particle swarm optimization for removal of methyl orange by gold nanoparticles loaded on activated carbon and Tamarisk.

    PubMed

    Ghaedi, M; Ghaedi, A M; Ansari, A; Mohammadi, F; Vafaei, A

    2014-11-11

    The influence of variables, namely initial dye concentration, adsorbent dosage (g), stirrer speed (rpm) and contact time (min) on the removal of methyl orange (MO) by gold nanoparticles loaded on activated carbon (Au-NP-AC) and Tamarisk were investigated using multiple linear regression (MLR) and artificial neural network (ANN) and the variables were optimized by partial swarm optimization (PSO). Comparison of the results achieved using proposed models, showed the ANN model was better than the MLR model for prediction of methyl orange removal using Au-NP-AC and Tamarisk. Using the optimal ANN model the coefficient of determination (R2) for the test data set were 0.958 and 0.989; mean squared error (MSE) values were 0.00082 and 0.0006 for Au-NP-AC and Tamarisk adsorbent, respectively. In this study a novel and green approach were reported for the synthesis of gold nanoparticle and activated carbon by Tamarisk. This material was characterized using different techniques such as SEM, TEM, XRD and BET. The usability of Au-NP-AC and activated carbon (AC) Tamarisk for the methyl orange from aqueous solutions was investigated. The effect of variables such as pH, initial dye concentration, adsorbent dosage (g) and contact time (min) on methyl orange removal were studied. Fitting the experimental equilibrium data to various isotherm models such as Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich models show the suitability and applicability of the Langmuir model. Kinetic models such as pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion models indicate that the second-order equation and intraparticle diffusion models control the kinetic of the adsorption process. The small amount of proposed Au-NP-AC and activated carbon (0.015 g and 0.75 g) is applicable for successful removal of methyl orange (>98%) in short time (20 min for Au-NP-AC and 45 min for Tamarisk-AC) with high adsorption capacity 161 mg g(-1) for Au-NP-AC and 3.84 mg g(-1) for

  3. Tunning PID controller using particle swarm optimization algorithm on automatic voltage regulator system

    NASA Astrophysics Data System (ADS)

    Aranza, M. F.; Kustija, J.; Trisno, B.; Hakim, D. L.

    2016-04-01

    PID Controller (Proportional Integral Derivative) was invented since 1910, but till today still is used in industries, even though there are many kind of modern controllers like fuzz controller and neural network controller are being developed. Performance of PID controller is depend on on Proportional Gain (Kp), Integral Gain (Ki) and Derivative Gain (Kd). These gains can be got by using method Ziegler-Nichols (ZN), gain-phase margin, Root Locus, Minimum Variance dan Gain Scheduling however these methods are not optimal to control systems that nonlinear and have high-orde, in addition, some methods relative hard. To solve those obstacles, particle swarm optimization (PSO) algorithm is proposed to get optimal Kp, Ki and Kd. PSO is proposed because PSO has convergent result and not require many iterations. On this research, PID controller is applied on AVR (Automatic Voltage Regulator). Based on result of analyzing transient, stability Root Locus and frequency response, performance of PID controller is better than Ziegler-Nichols.

  4. Basis function repetitive and feedback control with application to a particle accelerator

    NASA Astrophysics Data System (ADS)

    Akogyeram, Raphael Akuete

    2002-09-01

    The thesis addresses three problem areas within repetitive control. Firstly, it addresses issues concerning the ability of repetitive control and feedback control systems to eliminate periodic disturbances occurring above the Nyquist frequency of the hardware. Methods are developed for decomposing and unfolding notch filter or comb filter feedback control so that disturbances above Nyquist frequency can be canceled. Phenomena affecting final error levels are discussed, including error in unfolding, coarseness of zero-order hold cancellation, and waterbed effects in the feedback control system frequency response for different sample rates. Secondly, matched basis function repetitive control laws are developed for batch mode and real time implementation to converge to zero tracking error in the presence of periodic disturbances. For both control methods, conditions are given that guarantee asymptotic and monotonic convergence. Stability tests are formulated to examine stability when the period of a disturbance is not an integer number of sample times, and when there are multiple unrelated periods whose common period is too long to use. Thirdly, an understanding is developed of the optimum division of labor between the objectives accomplished by feedback and the objectives accomplished by repetitive control action. Some experimental results of the particle accelerator testbed at Thomas Jefferson National Accelerator Facility, Newport News, Virginia, are reported.

  5. An In-situ materials analysis particle probe (MAPP) diagnostic to study particle density control and hydrogenic fuel retention in NSTX

    SciTech Connect

    Allain, Jean-Paul

    2014-09-05

    A new materials analysis particle probe (MAPP) was designed, constructed and tested to develop understanding of particle control and hydrogenic fuel retention in lithium-based plasma-facing surfaces in NSTX. The novel feature of MAPP is an in-situ tool to probe the divertor NSTX floor during LLD and lithium-coating shots with subsequent transport to a post-exposure in-vacuo surface analysis chamber to measure D retention. In addition, the implications of a lithiated graphite-dominated plasma-surface environment in NSTX on LLD performance, operation and ultimately hydrogenic pumping and particle control capability are investigated in this proposal. MAPP will be an invaluable tool for erosion/redeposition simulation code validation.

  6. Method for removing contaminants from plastic resin

    DOEpatents

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2008-12-09

    A resin recycling method that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The method includes receiving the resin in container form. The containers are then ground into resin particles. The particles are exposed to a solvent, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. After separating the particles and the resin, a solvent removing agent is used to remove any residual solvent remaining on the resin particles after separation.

  7. Morphological control of multihollow polymer latex particles through a controlled phase separation in the seeded emulsion polymerization.

    PubMed

    Li, Bingxin; Xu, Yongfei; Wang, Mozhen; Ge, Xuewu

    2013-12-03

    In this work, we first reported that the phase separation can take place both inside and outside of a multihollow-structured cross-linked seed microspheres swollen by styrene monomers in water during the radiation-induced seeded emulsion polymerization. The phase separation process in these two opposite directions will determine the morphology of final latex particles. First, sulfonated cross-linked polystyrene (SCPS) seed microspheres were swollen by styrene in water. Water will permeate into the SCPS seed microspheres during the swelling process, forced by the osmotic pressure produced by the strong hydrophilicity of the sulfonic acid groups. New aqueous phases are created and stabilized by the hydrophilic -SO3H groups, resulting in a multihollow structure of swollen SCPS seed microspheres. When the polymerization of styrene is induced by (60)Co γ-ray radiation, the phase separation of newly formed polystyrene phase will occur at the seed microsphere-water interface inside and/or outside of the SCPS seed microspheres through adjusting the diameter of seed microsphere, the content of cross-link agent, and the sulfonation degree of SCPS seed microspheres. As a result, SCPS latex particles with a variety of special morphologies, such as spherical multihollow, plum-like, and walnut-like latex particles were obtained. The results of this study provide not only a simple and interesting way to design and synthesize multihollow polymer latex particles with controllable surface morphologies but also a better understanding on phase separation mechanism during the swelling and polymerization of monomers in cross-linked amphiphilic polymer networks.

  8. Factors controlling aquatic dissolved inorganic nitrogen removal and export in suburban watersheds

    NASA Astrophysics Data System (ADS)

    Mineau, M.; Wollheim, W. M.; Stewart, R.; Daley, M.; McDowell, W. H.

    2013-12-01

    Human activity has accelerated the nitrogen (N) cycle and enriched the landscape with N which can result in eutrophication, especially in coastal zones where N is typically limiting. N exported to coastal zones is a function of both N loading to aquatic systems and N removal in transit through the river network. To determine drivers of dissolved inorganic nitrogen (DIN) removal and export from suburban river networks, we compared 2 well-studied suburban New-England watersheds. The Lamprey River watershed (474 km2) in NH has a mean population density of 53 inhabitants per km2 and feeds into the Great Bay estuary which is designated as N impaired. The Ipswich River (400 km2) in MA has a much higher population density with 302 inhabitants per km2 and feeds into the Plum Island estuary, which is not N impaired. Median (2000 - 2009) watershed DIN export was 171 kg km-2 y-1 for the Ipswich and 77 kg km-2 y-1 for the Lamprey. We used the Framework for Aquatic Modeling in the Earth System (FrAMES) to evaluate the relative importance of anthropogenic N loading and river network DIN processing in determining N export from these watersheds. FrAMES is a spatially distributed and time varying coupled hydrologic and biogeochemical model for river networks. We hypothesized that greater N export relative to population density in the Lamprey watershed was due in part to less aquatic N processing caused by interactions among: 1. The distribution of development/sources in the watershed (i.e. mean flow path length N has to travel), and 2. The area and distribution of intact fluvial wetlands in the watershed. We conducted a sensitivity analysis to determine the relative importance of these factors in limiting aquatic N removal in the Lamprey river watershed. Our results suggest that the distribution of loading within a river system has important influence on nutrient export to coastal zones.

  9. Removal of proprioception by BCI raises a stronger body ownership illusion in control of a humanlike robot

    PubMed Central

    Alimardani, Maryam; Nishio, Shuichi; Ishiguro, Hiroshi

    2016-01-01

    Body ownership illusions provide evidence that our sense of self is not coherent and can be extended to non-body objects. Studying about these illusions gives us practical tools to understand the brain mechanisms that underlie body recognition and the experience of self. We previously introduced an illusion of body ownership transfer (BOT) for operators of a very humanlike robot. This sensation of owning the robot’s body was confirmed when operators controlled the robot either by performing the desired motion with their body (motion-control) or by employing a brain-computer interface (BCI) that translated motor imagery commands to robot movement (BCI-control). The interesting observation during BCI-control was that the illusion could be induced even with a noticeable delay in the BCI system. Temporal discrepancy has always shown critical weakening effects on body ownership illusions. However the delay-robustness of BOT during BCI-control raised a question about the interaction between the proprioceptive inputs and delayed visual feedback in agency-driven illusions. In this work, we compared the intensity of BOT illusion for operators in two conditions; motion-control and BCI-control. Our results revealed a significantly stronger BOT illusion for the case of BCI-control. This finding highlights BCI’s potential in inducing stronger agency-driven illusions by building a direct communication between the brain and controlled body, and therefore removing awareness from the subject’s own body. PMID:27654174

  10. Removal of proprioception by BCI raises a stronger body ownership illusion in control of a humanlike robot.

    PubMed

    Alimardani, Maryam; Nishio, Shuichi; Ishiguro, Hiroshi

    2016-09-22

    Body ownership illusions provide evidence that our sense of self is not coherent and can be extended to non-body objects. Studying about these illusions gives us practical tools to understand the brain mechanisms that underlie body recognition and the experience of self. We previously introduced an illusion of body ownership transfer (BOT) for operators of a very humanlike robot. This sensation of owning the robot's body was confirmed when operators controlled the robot either by performing the desired motion with their body (motion-control) or by employing a brain-computer interface (BCI) that translated motor imagery commands to robot movement (BCI-control). The interesting observation during BCI-control was that the illusion could be induced even with a noticeable delay in the BCI system. Temporal discrepancy has always shown critical weakening effects on body ownership illusions. However the delay-robustness of BOT during BCI-control raised a question about the interaction between the proprioceptive inputs and delayed visual feedback in agency-driven illusions. In this work, we compared the intensity of BOT illusion for operators in two conditions; motion-control and BCI-control. Our results revealed a significantly stronger BOT illusion for the case of BCI-control. This finding highlights BCI's potential in inducing stronger agency-driven illusions by building a direct communication between the brain and controlled body, and therefore removing awareness from the subject's own body.

  11. Remote control radioactive-waste removal system uses modulated laser transmitter

    NASA Technical Reports Server (NTRS)

    Burcher, E. E.; Kopia, L. P.; Rowland, C. W.; Sinclair, A. R.

    1971-01-01

    Laser remote control system consists of transmitter, auto tracker, and receiver. Transmitter and tracker, packaged together and bore sighted, constitute control station, receiver is slave station. Model has five command channels and optical link operating range of 110 m.

  12. Particle swarm optimization method for the control of a fleet of Unmanned Aerial Vehicles

    NASA Astrophysics Data System (ADS)

    Belkadi, A.; Ciarletta, L.; Theilliol, D.

    2015-11-01

    This paper concerns a control approach of a fleet of Unmanned Aerial Vehicles (UAV) based on virtual leader. Among others, optimization methods are used to develop the virtual leader control approach, particularly the particle swarm optimization method (PSO). The goal is to find optimal positions at each instant of each UAV to guarantee the best performance of a given task by minimizing a predefined objective function. The UAVs are able to organize themselves on a 2D plane in a predefined architecture, following a mission led by a virtual leader and simultaneously avoiding collisions between various vehicles of the group. The global proposed method is independent from the model or the control of a particular UAV. The method is tested in simulation on a group of UAVs whose model is treated as a double integrator. Test results for the different cases are presented.

  13. Silver ion mediated shape control of platinum nanoparticles: Removal of silver by selective etching leads to increased catalytic activity

    SciTech Connect

    Grass, Michael E.; Yue, Yao; Habas, Susan E.; Rioux, Robert M.; Teall, Chelsea I.; Somorjai, G.A.

    2008-01-09

    A procedure has been developed for the selective etching of Ag from Pt nanoparticles of well-defined shape, resulting in the formation of elementally-pure Pt cubes, cuboctahedra, or octahedra, with a largest vertex-to-vertex distance of {approx}9.5 nm from Ag-modified Pt nanoparticles. A nitric acid etching process was applied Pt nanoparticles supported on mesoporous silica, as well as nanoparticles dispersed in aqueous solution. The characterization of the silica-supported particles by XRD, TEM, and N{sub 2} adsorption measurements demonstrated that the structure of the nanoparticles and the mesoporous support remained conserved during etching in concentrated nitric acid. Both elemental analysis and ethylene hydrogenation indicated etching of Ag is only effective when [HNO{sub 3}] {ge} 7 M; below this concentration, the removal of Ag is only {approx}10%. Ethylene hydrogenation activity increased by four orders of magnitude after the etching of Pt octahedra that contained the highest fraction of silver. High-resolution transmission electron microscopy of the unsupported particles after etching demonstrated that etching does not alter the surface structure of the Pt nanoparticles. High [HNO{sub 3}] led to the decomposition of the capping agent, polyvinylpyrollidone (PVP); infrared spectroscopy confirmed that many decomposition products were present on the surface during etching, including carbon monoxide.

  14. Performance analysis of a semiactive suspension system with particle swarm optimization and fuzzy logic control.

    PubMed

    Qazi, Abroon Jamal; de Silva, Clarence W; Khan, Afzal; Khan, Muhammad Tahir

    2014-01-01

    This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control.

  15. Performance Analysis of a Semiactive Suspension System with Particle Swarm Optimization and Fuzzy Logic Control

    PubMed Central

    Qazi, Abroon Jamal; de Silva, Clarence W.

    2014-01-01

    This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control. PMID:24574868

  16. MIMO regulation control design for magnetic steering of a ferromagnetic particle inside a fluidic environment

    NASA Astrophysics Data System (ADS)

    Afshar, Sepideh; Behrad Khamesee, Mir; Khajepour, Amir

    2015-10-01

    As an important development of medical instrumentation, minimally invasive therapeutic operations have been recently introduced. The foremost element of minimally invasive techniques is navigating a micro-device through human body, especially inside blood vessels. A remote actuation over the micro-device is normally provided by electromagnetic actuators. In most applications, a control scheme is also required to initiate the actuation force, the magnetic propulsion, such that at every time step, the micro-device moves towards or along a given path. This paper contributes in development of the electromagnetic system model mostly used in magnetic navigation systems to be representable in control affine form. Next, a multi-input multi-output (MIMO) trajectory tracking controller is designed to conduct the auto-navigation of the device along a given path. This method is a generalised version of a 'semi-global nonlinear output regulation' introduced for single-input single-output (SISO) systems. Finally, the proposed scheme is examined for an iron particle moving in a fluidic environment. The simulation results show fast decay in deviation of the particle position from the reference path under some assumptions. This shows that the proposed scheme can be offered for medical applications.

  17. Mathematical model for internal pH control in immobilized enzyme particles

    SciTech Connect

    Liou, J.K.; Rousseau, I.

    1986-10-01

    A mathematical model has been developed for the internal pH control in immobilized enzyme particles. This model describes the kinetics of a coupled system of two enzymes, immobilized in particles of either planar, cylindrical, or spherical shape. The enzyme kinetics are assumed to be of a mixed type, including Michaelis-Menten kinetics, uncompetitive substrate inhibition, and competitive and noncompetitive product inhibition. In a case study we have considered the enzyme combination urease and penicillin acylase, whose kinetics are coupled through the pH dependence of the kinetic parameters. The hydrolysis of urea by urease yields ammonia and carbon dioxide, whereas benzylpenicillin (Pen-G) is converted to 6-animo penicillanic acid and phenyl acetic acid by penicillin acylase. The production of acids by the latter enzyme will cause a decrease in pH. Because of the presence of the ammonia-carbon dioxide system, however, the pH may be kept under control. In order to obtain information about the optimum performance of this enzymatic pH controller, we have computed the effectiveness factor and the conversion in a CSTR at different enzyme loadings. The results of the computer simulations indicate that a high conversion of Pen-G may be achieved (80-90%) at bulk pH values of about 7.5 - 8. 27 references.

  18. Controlled removal of ceramic surfaces with combination of ions implantation and ultrasonic energy

    DOEpatents

    Boatner, Lynn A.; Rankin, Janet; Thevenard, Paul; Romana, Laurence J.

    1995-01-01

    A method for tailoring or patterning the surface of ceramic articles is provided by implanting ions to predetermined depth into the ceramic material at a selected surface location with the ions being implanted at a fluence and energy adequate to damage the lattice structure of the ceramic material for bi-axially straining near-surface regions of the ceramic material to the predetermined depth. The resulting metastable near-surface regions of the ceramic material are then contacted with energy pulses from collapsing, ultrasonically-generated cavitation bubbles in a liquid medium for removing to a selected depth the ion-damaged near-surface regions containing the bi-axially strained lattice structure from the ceramic body. Additional patterning of the selected surface location on the ceramic body is provided by implanting a high fluence of high-energy, relatively-light ions at selected surface sites for relaxing the bi-axial strain in the near-surface regions defined by these sites and thereby preventing the removal of such ion-implanted sites by the energy pulses from the collapsing ultrasonic cavitation bubbles.

  19. Controlled Contamination of Epoxy Composites with PDMS and Removal by Laser Ablation

    NASA Technical Reports Server (NTRS)

    Palmieri, Frank; Ledesma, Rodolfo; Cataldo, Daniel; Lin, Yi; Wohl, Christopher; Gupta, Mool; Connell, John

    2016-01-01

    Surface preparation is critical to the performance of adhesively bonded composites. During manufacturing, minute quantities of mold release compounds are inevitably deposited on faying surfaces and may compromise bond performance. To ensure safety, mechanical fasteners and other crack arrest features must be installed in the bondlines of primary structures, which negates some advantages of adhesively bonded construction. Laser ablation is an automated, repeatable, and scalable process with high potential for the surface preparation of metals and composites in critical applications such as primary airframe structures. In this study, laser ablation is evaluated on composite surfaces for the removal of polydimethylsiloxane (PDMS), a common mold release material. Composite panels were contaminated uniformly with PDMS film thicknesses as low as 6.0 nm as measured by variable angle spectroscopic ellipsometry. Bond performance was assessed by mechanical testing using a 250 F cure, epoxy adhesive and compared with pre-bond surface inspection results. Water contact angle, optically stimulated electron emission, and laser induced breakdown spectroscopy were used to characterize contaminated and laser ablated surfaces. The failure mode obtained from double cantilever beam tests correlated well with surface characterization data. The test results indicated that even low levels of PDMS were not completely removed by laser ablation.

  20. Efficacy of two soft-bristle toothbrushes in plaque removal: a randomized controlled trial.

    PubMed

    Rosing, Cassiano Kuchenbecker; Cavagni, Juliano; Gaio, Eduardo José; Muniz, Francisco Wilker Mustafa Gomes; Oballe, Harry Juan Rivera; Ranzan, Nicolle; Friedrich, Stephanie Anagnostopoulos; Severo, Raísa Maldonado; Gittins, Elizabeth; Stewart, Bernal; Zhang, Yun Po

    2016-11-10

    The aim of this study was to compare the efficacy in supragingival plaque removal of two soft-bristle toothbrushes. Seventy volunteers were allocated randomly to the Colgate Slim Soft or Curaprox CS5460 toothbrush grourps. At baseline appointment, volunteers underwent plaque examination using the Rustogi Modification of the Navy Plaque Index. Under supervision, they then brushed their teeth for 1minute with their assigned toothbrushes and the plaque examination was repeated. Volunteers performed daily oral hygiene with their assigned toothbrush and a regular dentifrice provided by the researchers for 7 days. The baseline experimental procedures were then repeated. Separate analyses of variance were performed for the whole-mouth, interproximal, and gumline plaque scores (p < 0.05). No difference in baseline pre-brushing scores was found between groups. After a single toothbrushing, the mean plaque score was significantly reduced in both groups (p < 0.05), with greater reduction of whole-mouth and interproximal plaque scores observed in the SlimSoft group compared with the Curaprox group (p < 0.05). After 7 days, the SlimSoft group showed greater reduction of the whole-mouth and interproximal plaque scores compared with the Curaprox group (p < 0.05). In conclusion, the SlimSoft toothbrush presented greater efficacy in supragingival plaque removal than did the Curaprox CS5460 toothbrush, as reflected by whole-mouth and interproximal plaque scores.

  1. Optimal control of switched linear systems based on Migrant Particle Swarm Optimization algorithm

    NASA Astrophysics Data System (ADS)

    Xie, Fuqiang; Wang, Yongji; Zheng, Zongzhun; Li, Chuanfeng

    2009-10-01

    The optimal control problem for switched linear systems with internally forced switching has more constraints than with externally forced switching. Heavy computations and slow convergence in solving this problem is a major obstacle. In this paper we describe a new approach for solving this problem, which is called Migrant Particle Swarm Optimization (Migrant PSO). Imitating the behavior of a flock of migrant birds, the Migrant PSO applies naturally to both continuous and discrete spaces, in which definitive optimization algorithm and stochastic search method are combined. The efficacy of the proposed algorithm is illustrated via a numerical example.

  2. Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

    NASA Astrophysics Data System (ADS)

    Yu, Jiaguo; Tang, Hua; Cheng, Bei; Zhao, Xiujian

    2004-10-01

    Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca2+]/[C2O42-] ratio and concentration of PSMA and CaC2O4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis.

  3. Acoustical vortices on a Chip for 3D single particle manipulation and vorticity control

    NASA Astrophysics Data System (ADS)

    Riaud, Antoine; Thomas, Jean-Louis; Bou Matar, Olivier; Baudoin, Michael

    Surface acoustic waves offer most of the basic functions required for on-chip actuation of fluids at small scales: efficient flow mixing, integrated pumping, particles separation, droplet displacement, atomization, division and fusion. Nevertheless some more advanced functions such as 3D particles manipulation and vorticity control require the introduction of some specific kind of waves called acoustic vortices. These helical waves propagate spinning around a phase singularity called the dark core. On the one hand, the beam angular momentum can be transferred to the fluid and create point-wise vorticity for confined mixing, and on the other the dark core can trap individual particles in an acoustic well for single object manipulation. In this presentation, I will show how acoustical vortices on-a-chip can be synthesized with a programmable electronics and an array of transducers. I will then highlight how some of their specificities can be used for acoustical tweezing and twisting. This work is supported by ANR Project No. ANR-12-BS09-0021-01 and ANR-12- BS09-0021-02, and Rgion Nord Pas de Calais.

  4. Control of the morphology and particle size of boehmite nanoparticles synthesized under hydrothermal conditions.

    PubMed

    Mathieu, Yannick; Lebeau, Bénédicte; Valtchev, Valentin

    2007-08-28

    The spontaneous nucleation under hydrothermal conditions often leads to aggregation of crystallizing particles, which is an undesired phenomenon when the goal is the preparation of nanocrystals with narrow particle size distribution. The present paper reports on the synthesis of boehmite nanocrystals under hydrothermal conditions. An aqueous aluminum chloride salt solution was first prepared, and the pH was increased to 11 using a 5 M sodium hydroxide solution. The hydrothermal treatment was performed at 160 degrees C for different periods of time. The system yielded relatively small (15-40 nm) boehmite crystallites aggregated into larger (160 nm) particles. To avoid the aggregation, a biocompatible polymer, sodium polyacrylate (NaPa) 2100, was employed as a size-/morphology-controlling agent. Thus, stable colloidal suspensions of rounded boehmite nanoparticles having a size between 15 and 40 nm were obtained at 160 degrees C for 24 h. Further, the effect of synthesis time on the morphological features of boehmite synthesized in such a NaPa-containing system was investigated. The increase of the synthesis time from 24 to 168 h resulted in the formation of very long boehmite fibers (1000-2000 nm) with an average diameter of about 10 nm. The boehmite samples were characterized by XRD, DLS, TEM, IR, N2 adsorption, and zeta potential measurements. The colloidal stability of the obtained suspension was also studied.

  5. Nonaqueous magnetic nanoparticle suspensions with controlled particle size and nuclear magnetic resonance properties.

    PubMed

    Meledandri, Carla J; Stolarczyk, Jacek K; Ghosh, Swapankumar; Brougham, Dermot F

    2008-12-16

    We report the preparation of monodisperse maghemite (gamma-Fe2O3) nanoparticle suspensions in heptane, by thermal decomposition of iron(III) acetylacetonate in the presence of oleic acid and oleylamine surfactants. By varying the surfactant/Fe precursor mole ratio during synthesis, control was exerted both over the nanocrystal core size, in the range from 3 to 6 nm, and over the magnetic properties of the resulting nanoparticle dispersions. We report field-cycling 1H NMR relaxation analysis of the superparamagnetic relaxation rate enhancement of nonaqueous suspensions for the first time. This approach permits measurement of the relaxivity and provides information on the saturation magnetization and magnetic anisotropy energy of the suspended particles. The saturation magnetization was found to be in the expected range for maghemite particles of this size. The anisotropy energy was found to increase significantly with decreasing particle size, which we attribute to increased shape anisotropy. This study can be used as a guide for the synthesis of maghemite nanoparticles with selected magnetic properties for a given application.

  6. Effect of initial pH control on biological phosphorus removal induced by the aerobic/extended-idle regime.

    PubMed

    Wang, Dongbo; Zheng, Wei; Liao, Dexiang; Li, Xiaoming; Yang, Qi; Zeng, Guangming

    2013-02-01

    Recently, it has been reported that biological phosphorus removal (BPR) can be induced by an aerobic/extended-idle (AEI) regime. This study further investigated the effect of initial pH ranging from 6.6 to 8.2 on BPR in the AEI process, and compared the BPR performance between the AEI and the anaerobic/oxic (A/O) regimes under their optimal initial pH value. Experimental results firstly showed that phosphorus removal linearly increased with initial pH increasing from 6.6 to 7.8, but slightly decreased when initial pH increased from 7.8 to 8.2. The optimal initial pH should be controlled at 7.8, and the phosphorus removal at initial pH 7.8 was approximately 1.7-time than that at initial pH 6.6. The mechanism studies showed that the biomass cultured at initial pH 7.8 contained more polyphosphate accumulating organisms (PAOs), lower glycogen accumulating organisms (GAOs), and had higher activities of exopolyphosphatase and polyphosphate kinase than that cultured at initial pH 6.6. Cyclic studies revealed that initial pH control affected the transformations of intracellular polyhydroxyalkanoates and glycogen, which might thereby influence microbial competition between PAOs and GAOs. Then, BPR performance between the AEI and the A/O regimes by adjusting initial pH at 7.8 was also compared. The results showed the AEI regime could drive a better BPR than the generally accepted A/O regime (98% vs 88%). Finally, controlling initial pH at 7.8 to promote BPR in the AEI process was confirmed for a municipal wastewater.

  7. UV254 absorbance as real-time monitoring and control parameter for micropollutant removal in advanced wastewater treatment with powdered activated carbon.

    PubMed

    Altmann, Johannes; Massa, Lukas; Sperlich, Alexander; Gnirss, Regina; Jekel, Martin

    2016-05-01

    This study investigates the applicability of UV absorbance measurements at 254 nm (UVA254) to serve as a simple and reliable surrogate parameter to monitor and control the removal of organic micropollutants (OMPs) in advanced wastewater treatment applying powdered activated carbon (PAC). Correlations between OMP removal and corresponding UVA254 reduction were determined in lab-scale adsorption batch tests and successfully applied to a pilot-scale PAC treatment stage to predict OMP removals in aggregate samples with good accuracy. Real-time UVA254 measurements were utilized to evaluate adapted PAC dosing strategies and proved to be effective for online monitoring of OMP removal. Furthermore, active PAC dosing control according to differential UVA254 measurements was implemented and tested. While precise removal predictions based on real-time measurements were not accurate for all OMPs, UVA254-controlled dynamic PAC dosing was capable of achieving stable OMP removals. UVA254 can serve as an effective surrogate parameter for OMP removal in technical PAC applications. Even though the applicability as control parameter to adjust PAC dosing to water quality changes might be limited to applications with fast response between PAC adjustment and adsorptive removal (e.g. direct filtration), UVA254 measurements can also be used to monitor the adsorption efficiency in more complex PAC applications.

  8. Surfactant modified coir pith, an agricultural solid waste as adsorbent for phosphate removal and fertilizer carrier to control phosphate release.

    PubMed

    Namasivayam, C; Kumar, M V Suresh

    2005-10-01

    The surface of coir pith, an agricultural solid waste was modified using a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA) and the modified coir pith was investigated to assess the capacity for the removal of phosphate from aqueous solution. Optimum pH for maximum phosphate adsorption was found to be 4.0. Langmuir and Freundlich isotherms were used to model the adsorption equilibrium data. Kinetic studies showed that the adsorption obeyed second order kinetics. Thermodynamic parameters were evaluated and the overall adsorption process was spontaneous and endothermic. Effect of coexisting anions has also been studied. The feasibility of using spent adsorbent as fertilizer carrier to control phosphate release was also investigated.

  9. The effect of electrical properties for InGaN and InN by high-energy particle irradiation (notice of removal)

    NASA Astrophysics Data System (ADS)

    Dong, Shao-guang; Fan, Guang-han

    2008-03-01

    This paper (SPIE Paper 68411H) was removed from the SPIE Digital Library on 8 August 2008 upon discovery that the paper has substantially plagiarized the following two papers: R.E. Jones, S.X. Li, L. Hsu, K.M. Yu, W. Walukiewicz, Z. Liliental-Weber, J.W. Ager III, E.E. Haller, H. Lu, and W.J. Schaff, "Native-defect-controlled n-type conductivity in InN," Physica B 376-377 (2006) 436-439 and S.X. Li, K.M. Yu, J. Wu, R.E. Jones, W. Walukiewicz, J.W. Ager III, W. Shan, E.E. Haller, Hai Lu, and William J. Schaff, "Native defects in InxGa1-xN alloys," Physica B 376-377 (2006) 432-435. As stated in the SPIE Publication Ethics Guidelines, "SPIE defines plagiarism as the reuse of someone else's prior ideas, processes, results, or words without explicit attribution of the original author and source, or falsely representing someone else's work as one's own. Unauthorized use of another researcher's unpublished data or findings without permission is considered to be a form of plagiarism even if the source is attributed. SPIE considers plagiarism in any form, at any level, to be unacceptable and a serious breach of professional conduct." It is SPIE policy to remove such papers and to provide citations to original sources so that interested readers can obtain the information directly from those sources. One of the authors, Shao-guang Dong, accepts full responsibility and apologizes for this plagiarism and has absolved the second author, Guang-han Fan, of any prior knowledge of or professional misconduct in this matter. Guang-han Fan also states that he had not previously seen the paper or given permission to include his name as an author.

  10. Configurations and control of magnetic fields for manipulating magnetic particles in microfluidic applications: magnet systems and manipulation mechanisms.

    PubMed

    Cao, Quanliang; Han, Xiaotao; Li, Liang

    2014-08-07

    The use of a magnetic field for manipulating the motion of magnetic particles in microchannels has attracted increasing attention in microfluidic applications. Generation of a flexible and controllable magnetic field plays a crucial role in making better use of the particle manipulation technology. Recent advances in the development of magnet systems and magnetic field control methods have shown that it has great potential for effective and accurate manipulation of particles in microfluidic systems. Starting with the analysis of magnetic forces acting on the particles, this review gives the configurations and evaluations of three main types of magnet system proposed in microfluidic applications. The interaction mechanisms of magnetic particles with magnetic fields are also discussed.

  11. Full-cyclic control strategy of SBR for nitrogen removal in strong wastewater using common sensors.

    PubMed

    Poo, K M; Im, J H; Jun, B H; Kim, J R; Hwang, I S; Choi, K S; Kim, C W

    2006-01-01

    A full-cyclic automatic control strategy for sequencing batch reactors (SBR) was proposed using only common sensors such as ORP, DO and pH. The main objective was to develop a generally applicable and robust control strategy. To accomplish this, various control schemes found in the literature or suggested by authors were examined at diverse ammonia loads and SCOD/NH4(+)-N ratios. Advantages and constraints of each scheme were discussed and compared. Ammonia load was estimated with DO lag time during the aerobic stage, and then the influent pump was manipulated to meet the desired load at the next anoxic stage. A partial denitrification scheme was chosen for the anoxic stage period control, to save anoxic time and external carbon. For external carbon dosage control, intermittent feeding at each anoxic stage was concluded to be a suitable scheme. The anoxic stage period could be successfully controlled by the combination of pH increase and DO increase. Every suggested control scheme was incorporated into a full-cyclic control strategy and tested at 0.02, 0.035, 0.08 kg NH4(+)-N/m3/sub-cycle. From the results, it is expected to perform unmanned automatic SBR operation with this strategy.

  12. Control of degreening in postharvest green sour citrus fruit by electrostatic atomized water particles.

    PubMed

    Yamauchi, Naoki; Takamura, Kohtaro; Shigyo, Masayoshi; Migita, Catharina Taiko; Masuda, Yukihiro; Maekawa, Tetsuya

    2014-08-01

    The effect of electrostatic atomized water particles (EAWP) on degreening of green sour citrus fruit during storage was determined. Superoxide anion and hydroxyl radicals included in EAWP were present on the surface of the fruit peel after the treatment. Hydrogen peroxide was formed from EAWP in an aqueous solution, which could indicate that a hydroxyl radical of EAWP turns to hydrogen peroxide in the fruit flavedo as well as in the aqueous solution. EAWP treatment effectively suppressed the degreening of green yuzu and Nagato-yuzukichi fruits during storage at 20°C. The enhancement in K+ ion leakage of both EAWP-treated fruits reduced in comparison with the control. In spite of EAWP treatment, total peroxide level in both fruits showed almost no changes during storage, suggesting that hydrogen peroxide formed by EAWP treatment could stimulate the activation of hydrogen peroxide scavenging system and control degreening of these fruits during storage.

  13. First Steps Toward Incorporating Image Based Diagnostics Into Particle Accelerator Control Systems Using Convolutional Neural Networks

    SciTech Connect

    Edelen, A. L.; Biedron, S. G.; Milton, S. V.; Edelen, J. P.

    2016-12-16

    At present, a variety of image-based diagnostics are used in particle accelerator systems. Often times, these are viewed by a human operator who then makes appropriate adjustments to the machine. Given recent advances in using convolutional neural networks (CNNs) for image processing, it should be possible to use image diagnostics directly in control routines (NN-based or otherwise). This is especially appealing for non-intercepting diagnostics that could run continuously during beam operation. Here, we show results of a first step toward implementing such a controller: our trained CNN can predict multiple simulated downstream beam parameters at the Fermilab Accelerator Science and Technology (FAST) facility's low energy beamline using simulated virtual cathode laser images, gun phases, and solenoid strengths.

  14. The role of kaolin particles in the performance of a carbamate-based biocide for water bacterial control.

    PubMed

    Pereira, Maria Olivia; Vieira, Maria João; Melo, Luis F

    2002-01-01

    The influence of kaolin particles on the activity of Pseudomonas fluorescens and on the efficacy of a carbamate-based biocide was investigated. The results indicated that kaolin particles stimulated the activity of the bacteria for all buffered pH values studied (5, 7, and 9); this effect being more evident for the tests carried out at pH 5 and 9. The presence of the clay in P. fluorescens suspensions decreased the efficiency of disinfection of the carbamate. The results also showed that kaolin was very effective in removing carbamate from the culture media. Therefore, the biocide concentration in the solution decreased, and consequently its availability to the bacteria was reduced. The results could be explained by the interaction between kaolin particles and carbamate and by the changes in the configuration of kaolin aggregates, depending on the pH value.

  15. Modeling and control of a space robot for active debris removal

    NASA Astrophysics Data System (ADS)

    Dubanchet, Vincent; Saussié, David; Alazard, Daniel; Bérard, Caroline; Peuvédic, Catherine Le

    2015-06-01

    Space access and satellites lifespan are increasingly threatened by the great amount of debris in Low Earth Orbits. Among the many solutions proposed in the literature so far, the emphasis is put here on a robotic arm mounted on a "chaser" satellite to capture massive debris, such as dead satellites or launch vehicle upper stages. The modeling and control of such systems are investigated throughout the paper. Dynamic models rely on an adapted Newton-Euler algorithm, and control algorithms are based on the fixed-structure H_{&infty}; synthesis, recently implemented in an efficient Matlab toolbox. The main goal is to efficiently track a target point on the debris while using PD-like controllers to reduce computational burden. The fixed-structure H_{∞} framework proves to be a suitable tool to design a reduced-order robust controller that catches up with external disturbances and is simultaneously compatible with current space processors capabilities.

  16. Evaluation of secondary coolant control design alternatives and their effects on heat removal performance

    SciTech Connect

    Khayat, M.I.; Anderson, J.; Battle, R.; March-Leuba, J.

    1994-03-01

    This report documents a series of calculations that evaluate the performance of the core-inlet temperature controller under different transient conditions and design options. The present analyses show that the core-inlet temperature can be controlled at {approx}45{degrees}C under all transient conditions analyzed using the controller design described in the conceptual design report, which includes variable-speed secondary coolant pumps and variable-speed cooling tower fans. This study also shows that a constant-speed secondary pump would be sufficient to maintain core-inlet temperature <45{degrees}C if this temperature is allowed to drop below the set point during some demanding transients, such as normal startup. The use of secondary loop hot coolant to warm the reactor building was also evaluated; however, optimization of the secondary hot-leg temperature can only be achieved by trading off control of the primary side core-inlet temperature.

  17. Spatial control of chromosomal location in a live cell with functionalized magnetic particles

    NASA Astrophysics Data System (ADS)

    Hong, Juhee; Purwar, Prashant; Cha, Misun; Lee, Junghoon

    2015-11-01

    Long-range chromosomal travel is a phenomenon unique to cell division. Methods for non-invasive, artificial manipulation of chromosomes, such as optical or magnetic tweezers, have difficulty in producing the motion of whole chromosomes in live cells. Here, we report the spatial control of chromosomes over 10 μm in a live mouse oocyte using magnetic particles driven by an external magnetic field. Selective capture of the chromosomes was achieved using antibodies specific for histone H1 in the chromosome that were conjugated to magnetic particles (H1-BMPs). When an external magnetic field was applied, the chromosomes captured by the H1-BMPs traveled through the cytosol and accumulated near the cell membrane though the movement of the chromosomes captured by H1-BMPs was strongly disturbed by the distribution of the cytoskeleton (e.g. actin filaments). Being non-invasive in nature, our approach will enable new opportunities in the remote manipulation of subcellular elements.Long-range chromosomal travel is a phenomenon unique to cell division. Methods for non-invasive, artificial manipulation of chromosomes, such as optical or magnetic tweezers, have difficulty in producing the motion of whole chromosomes in live cells. Here, we report the spatial control of chromosomes over 10 μm in a live mouse oocyte using magnetic particles driven by an external magnetic field. Selective capture of the chromosomes was achieved using antibodies specific for histone H1 in the chromosome that were conjugated to magnetic particles (H1-BMPs). When an external magnetic field was applied, the chromosomes captured by the H1-BMPs traveled through the cytosol and accumulated near the cell membrane though the movement of the chromosomes captured by H1-BMPs was strongly disturbed by the distribution of the cytoskeleton (e.g. actin filaments). Being non-invasive in nature, our approach will enable new opportunities in the remote manipulation of subcellular elements. Electronic supplementary

  18. Removal of electrostatic artifacts in magnetic force microscopy by controlled magnetization of the tip: application to superparamagnetic nanoparticles.

    PubMed

    Angeloni, Livia; Passeri, Daniele; Reggente, Melania; Mantovani, Diego; Rossi, Marco

    2016-05-19

    Magnetic force microscopy (MFM) has been demonstrated as valuable technique for the characterization of magnetic nanomaterials. To be analyzed by MFM techniques, nanomaterials are generally deposited on flat substrates, resulting in an additional contrast in MFM images due to unavoidable heterogeneous electrostatic tip-sample interactions, which cannot be easily distinguished from the magnetic one. In order to correctly interpret MFM data, a method to remove the electrostatic contributions from MFM images is needed. In this work, we propose a new MFM technique, called controlled magnetization MFM (CM-MFM), based on the in situ control of the probe magnetization state, which allows the evaluation and the elimination of electrostatic contribution in MFM images. The effectiveness of the technique is demonstrated through a challenging case study, i.e., the analysis of superparamagnetic nanoparticles in absence of applied external magnetic field. Our CM-MFM technique allowed us to acquire magnetic images depurated of the electrostatic contributions, which revealed that the magnetic field generated by the tip is sufficient to completely orient the superparamagnetic nanoparticles and that the magnetic tip-sample interaction is describable through simple models once the electrostatic artifacts are removed.

  19. Dynamic axial control over optically levitating particles in air with an electrically-tunable variable-focus lens

    PubMed Central

    Zhu, Wenguo; Eckerskorn, Niko; Upadhya, Avinash; Li, Li; Rode, Andrei V.; Lee, Woei Ming

    2016-01-01

    Efficient delivery of viruses, proteins and biological macromelecules into a micrometer-sized focal spot of an XFEL beam for coherent diffraction imaging inspired new development in touch-free particle injection methods in gaseous and vacuum environments. This paper lays out our ongoing effort in constructing an all-optical particle delivery approach that uses piconewton photophoretic and femtonewton light-pressure forces to control particle delivery into the XFEL beam. We combine a spatial light modulator (SLM) and an electrically tunable lens (ETL) to construct a variable-divergence vortex beam providing dynamic and stable positioning of levitated micrometer-size particles, under normal atmospheric pressure. A sensorless wavefront correction approach is used to reduce optical aberrations to generate a high quality vortex beam for particle manipulation. As a proof of concept, stable manipulation of optically-controlled axial motion of trapped particles is demonstrated with a response time of 100ms. In addition, modulation of trapping intensity provides a measure of the mass of a single, isolated particle. The driving signal of this oscillatory motion can potentially be phase-locked to an external timing signal enabling synchronization of particle delivery into the x-ray focus with XFEL pulse train. PMID:27446715

  20. In-flight monitoring of particle deposition in the environmental control systems of commercial airliners in China

    NASA Astrophysics Data System (ADS)

    Cao, Qing; Xu, Qiuyu; Liu, Wei; Lin, Chao-Hsin; Wei, Daniel; Baughcum, Steven; Norris, Sharon; Chen, Qingyan

    2017-04-01

    Severe air pollution and low on-time performance of commercial flights in China could increase particle deposition in the environmental control systems (ECSs) of commercial airliners. The particles deposited in the ECSs could negatively affect the performance of the airplanes. In addition, particles that penetrate into the aircraft cabin could adversely impact the health of passengers and crew members. This investigation conducted simultaneous measurements of particle mass concentration and size distribution inside and outside the cabin during 64 commercial flights of Boeing 737 and Airbus 320 aircraft departing from or arriving at Tianjin Airport in China. The results showed that the PM2.5 mass concentration deposition in the ECSs of these airplanes ranged from 50% to 90%, which was much higher than that measured in an airplane with a ground air-conditioning unit. The average deposition rates of particles with diameters of 0.5-1 μm, 1-2 μm, 2-5 μm, 5-10 μm, and >10 μm were 89 ± 8%, 85 ± 13%, 80 ± 13%, 73 ± 15%, and 80 ± 14%, respectively. The in-flight measurement results indicated that the particle concentration in the breathing zone was higher than that in the air-supply zone, which implies a significant contribution by particles in the interior of the cabin. Such particles come from human emissions or particle resuspension from interior surfaces.

  1. The ``coffee-ring effect'' as a way to remove pollutants and control drying rate in porous media

    NASA Astrophysics Data System (ADS)

    Keita, Emmanuel; Faure, Paméla; Rodts, Stéphane; Weitz, David A.; Coussot, Philippe

    2012-11-01

    Due to the transport of elements they induce imbibition-drying cycles are known to play a major role in the colloid-facilitated transport in soils and building materials. We study the drying of a colloidal suspension in a porous media. The critical physical phenomenon at work here is the displacement and redistribution of colloidal particles or ions induced by evaporation of the liquid phase from the porous medium. This can be clearly seen by filling a bead packing with coffee. Indeed after full drying the sample has shaded tones with darker regions around the sample free surface and white regions almost free of particles around the bottom. The mechanisms are not yet fully understood and there is no straightforward observation and simple quantification of the spreading of the elements. Using a new MRI technique to look at a complex porous media with colloidal particles in suspension in water we show that the drying of a porous medium filled with elements in the advection regime develops a specific coffee-ring effect. We can quantify how the elements migrate towards the free surface of the sample and accumulate in the remaining liquid films. Our complete understanding of the process makes it possible to establish a simple model predicting the drying rate and the concentration distribution. This opens the way to a control of salt or colloid transport and drying rate of soils and building materials.

  2. Novel apparatus and methods for performing remotely controlled particle-solid interaction experiments at CERN

    NASA Astrophysics Data System (ADS)

    Krause, H. F.; Deveney, E. F.; Jones, N. L.; Vane, C. R.; Datz, S.; Knudsen, H.; Grafström, P.; Schuch, R.

    1997-04-01

    Recent atomic physics studies involving ultrarelativistic Pb ions required solid target positioners, scintillators, and a sophisticated data acquisition and control system placed in a remote location at the CERN Super Proton Synchrotron near Geneva, Switzerland. The apparatus, installed in a high-radiation zone underground, had to (i) function for months, (ii) automatically respond to failures such as power outages and particle-induced computer upsets, and (iii) communicate with the outside world via a telephone line. The heart of the apparatus developed was an Apple Macintosh-based CAMAC system that answered the telephone and interpreted and executed remote control commands that (i) sensed and set targets, (ii) controlled voltages and discriminator levels for scintillators, (iii) modified data acquisition hardware logic, (iv) reported control information, and (v) automatically synchronized data acquisition to the CERN spill cycle via a modem signal and transmitted experimental data to a remote computer. No problems were experienced using intercontinental telephone connections at 1200 baud. Our successful "virtual laboratory" approach that uses off-the-shelf electronics is generally adaptable to more conventional bench-type experiments.

  3. System for removing contaminants from plastic resin

    DOEpatents

    Bohnert, George W.; Hand, Thomas E.; DeLaurentiis, Gary M.

    2010-11-23

    A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

  4. A simple route to synthesize conductive stimuli-responsive polypyrrole nanocomposite hydrogel particles with strong magnetic properties and their performance for removal of hexavalent chromium ions from aqueous solution

    NASA Astrophysics Data System (ADS)

    Ahmad, Hasan; Rahman, Mohammad Mostafizar; Ali, Mohammad Azgar; Minami, Hideto; Tauer, Klaus; Gafur, Mohammad Abdul; Rahman, Mohammad Mahbubor

    2016-08-01

    A combination of maghemite polypyrrole (PPy/γ-Fe2O3) and stimuli-responsive properties in the same hydrogel microspheres is expected to enhance their application potential in various fields such as tissue engineering, regenerative medicine, biosensors, biomedical applications and removal of heavy metals from waste water, catalysis etc. In this investigation a simple two step process is used to prepare conductive stimuli-responsive polypyrrole (PPy) composite hydrogel particles with strong magnetic properties. Poly(styrene-methacrylic acid-N-isopropylacrylamide-polyethelene glycol methacrylate) or P(S-NIPAM-MAA-PEGMA) hydrogel seed particles are first prepared by soap-free precipitation copolymerization. The copolymer hydrogel particles exhibited both temperature- and pH-responsive volume phase transition. Conductive P(S-NIPAM-MAA-PEGMA)/PPy/γ-Fe2O3 nanocomposite hydrogel particles are then prepared by seeded chemical oxidative polymerization of pyrrole in the presence of P(S-NIPAM-MAA-PEGMA) hydrogel seed particles using FeCl3 as a oxidant and p-toluene sulfonic acid (p-TSA) as a dopant. In the reaction system FeCl3 functioned as a source of Fe(III) for the formation of γ-Fe2O3. This reaction also requires the initial presence of Fe(II) provided by the addition of FeCl2. The size and size distribution, surface structure, and morphology of the prepared conductive composite hydrogel particles are confirmed by FTIR, electron micrographs, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV-visible spectroscopy. The performance of nanocomposite hydrogel particles has been evaluated for the removal of hexavalent chromium (Cr) ions from water.

  5. Control of reactor coolant flow path during reactor decay heat removal

    DOEpatents

    Hunsbedt, Anstein N.

    1988-01-01

    An improved reactor vessel auxiliary cooling system for a sodium cooled nuclear reactor is disclosed. The sodium cooled nuclear reactor is of the type having a reactor vessel liner separating the reactor hot pool on the upstream side of an intermediate heat exchanger and the reactor cold pool on the downstream side of the intermediate heat exchanger. The improvement includes a flow path across the reactor vessel liner flow gap which dissipates core heat across the reactor vessel and containment vessel responsive to a casualty including the loss of normal heat removal paths and associated shutdown of the main coolant liquid sodium pumps. In normal operation, the reactor vessel cold pool is inlet to the suction side of coolant liquid sodium pumps, these pumps being of the electromagnetic variety. The pumps discharge through the core into the reactor hot pool and then through an intermediate heat exchanger where the heat generated in the reactor core is discharged. Upon outlet from the heat exchanger, the sodium is returned to the reactor cold pool. The improvement includes placing a jet pump across the reactor vessel liner flow gap, pumping a small flow of liquid sodium from the lower pressure cold pool into the hot pool. The jet pump has a small high pressure driving stream diverted from the high pressure side of the reactor pumps. During normal operation, the jet pumps supplement the normal reactor pressure differential from the lower pressure cold pool to the hot pool. Upon the occurrence of a casualty involving loss of coolant pump pressure, and immediate cooling circuit is established by the back flow of sodium through the jet pumps from the reactor vessel hot pool to the reactor vessel cold pool. The cooling circuit includes flow into the reactor vessel liner flow gap immediate the reactor vessel wall and containment vessel where optimum and immediate discharge of residual reactor heat occurs.

  6. Controlling healthcare costs by removing waste: what American doctors can do now.

    PubMed

    Swensen, Stephen J; Kaplan, Gary S; Meyer, Gregg S; Nelson, Eugene C; Hunt, Gordon C; Pryor, David B; Weissberg, Jed I; Daley, Jennifer; Yates, Gary R; Chassin, Mark R

    2011-06-01

    Healthcare costs are unsustainable. The authors propose a solution to control costs without rationing (deliberate withholding of effective care) or payment reductions to doctors and hospitals. Three physician-led strategies comprise this solution: reduce (1) overuse of health services, (2) preventable complications and (3) waste within healthcare processes. These challenges know no borders.

  7. Trophic cascades in a cranberry marsh: Can detritus-removal improve biological control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biological pest control is predicated on the concept that plants are protected when carnivores suppress herbivore populations. However, many factors, including detritus-based food-chains, may re-shape the effectiveness of predators in a given agro ecosystem. The addition of detrital subsidies, such ...

  8. Optimal control system design of an acid gas removal unit for an IGCC power plants with CO2 capture

    SciTech Connect

    Jones, D.; Bhattacharyya, D.; Turton, R.; Zitney, S.

    2012-01-01

    Future IGCC plants with CO{sub 2} capture should be operated optimally in the face of disturbances without violating operational and environmental constraints. To achieve this goal, a systematic approach is taken in this work to design the control system of a selective, dual-stage Selexol-based acid gas removal (AGR) unit for a commercial-scale integrated gasification combined cycle (IGCC) power plant with pre-combustion CO{sub 2} capture. The control system design is performed in two stages with the objective of minimizing the auxiliary power while satisfying operational and environmental constraints in the presence of measured and unmeasured disturbances. In the first stage of the control system design, a top-down analysis is used to analyze degrees of freedom, define an operational objective, identify important disturbances and operational/environmental constraints, and select the control variables. With the degrees of freedom, the process is optimized with relation to the operational objective at nominal operation as well as under the disturbances identified. Operational and environmental constraints active at all operations are chosen as control variables. From the results of the optimization studies, self-optimizing control variables are identified for further examination. Several methods are explored in this work for the selection of these self-optimizing control variables. Modifications made to the existing methods will be discussed in this presentation. Due to the very large number of candidate sets available for control variables and due to the complexity of the underlying optimization problem, solution of this problem is computationally expensive. For reducing the computation time, parallel computing is performed using the Distributed Computing Server (DCS®) and the Parallel Computing® toolbox from Mathworks®. The second stage is a bottom-up design of the control layers used for the operation of the process. First, the regulatory control layer is

  9. Guidance, Navigation, and Control Techniques and Technologies for Active Satellite Removal

    NASA Astrophysics Data System (ADS)

    Ortega Hernando, Guillermo; Erb, Sven; Cropp, Alexander; Voirin, Thomas; Dubois-Matra, Olivier; Rinalducci, Antonio; Visentin, Gianfranco; Innocenti, Luisa; Raposo, Ana

    2013-09-01

    This paper shows an internal feasibility analysis to de- orbit a non-functional satellite of big dimensions by the Technical Directorate of the European Space Agency ESA. The paper focuses specifically on the design of the techniques and technologies for the Guidance, Navigation, and Control (GNC) system of the spacecraft mission that will capture the satellite and ultimately will de-orbit it on a controlled re-entry.The paper explains the guidance strategies to launch, rendezvous, close-approach, and capture the target satellite. The guidance strategy uses chaser manoeuvres, hold points, and collision avoidance trajectories to ensure a safe capture. It also details the guidance profile to de-orbit it in a controlled re-entry.The paper continues with an analysis of the required sensing suite and the navigation algorithms to allow the homing, fly-around, and capture of the target satellite. The emphasis is placed around the design of a system to allow the rendezvous with an un-cooperative target, including the autonomous acquisition of both the orbital elements and the attitude of the target satellite.Analysing the capture phase, the paper provides a trade- off between two selected capture systems: the net and the tentacles. Both are studied from the point of view of the GNC system.The paper analyses as well the advanced algorithms proposed to control the final compound after the capture that will allow the controlled de-orbiting of the assembly in a safe place in the Earth.The paper ends proposing the continuation of this work with the extension to the analysis of the destruction process of the compound in consecutive segments starting from the entry gate to the rupture and break up.

  10. Particle designs for the stabilization and controlled-delivery of protein drugs by biopolymers: a case study on insulin.

    PubMed

    Lim, Hui-Peng; Tey, Beng-Ti; Chan, Eng-Seng

    2014-07-28

    Natural biopolymers have attracted considerable interest for the development of delivery systems for protein drugs owing to their biocompatibility, non-toxicity, renewability and mild processing conditions. This paper offers an overview of the current status and future perspectives of particle designs using biopolymers for the stabilization and controlled-delivery of a model protein drug--insulin. We first describe the design criteria for polymeric encapsulation and subsequently classify the basic principles of particle fabrication as well as the existing particle designs for oral insulin encapsulation. The performances of these existing particle designs in terms of insulin stability and in vitro release behavior in acidic and alkaline media, as well as their in vivo performance are compared and reviewed. This review forms the basis for future works on the optimization of particle design and material formulation for the development of an improved oral delivery system for protein drugs.

  11. Classification of Volatile Engine Particles

    SciTech Connect

    Cheng, Mengdawn

    2013-01-01

    Volatile particles cannot be detected at the engine exhaust by an aerosol detector. They are formed when the exhaust is mixed with ambient air downstream. Lack of a precise definition of volatile engine particles has been an impediment to engine manufacturers and regulatory agencies involved in the development of an effective control strategy. It is beyond doubt that volatile particles from combustion sources contribute to the atmospheric particulate burden, and the effect of that contribution is a critical issue in the ongoing research in the areas of air quality and climate change. A new instrument, called volatile particle separator (VPS), has been developed. It utilizes a proprietary microporous metallic membrane to separate particles from vapors. VPS data were used in the development of a two-parameter function to quantitatively classify, for the first time, the volatilization behavior of engine particles. The value of parameter A describes the volatilization potential of an aerosol. A nonvolatile particle has a larger A-value than a volatile one. The value of parameter k, an effective evaporation energy barrier, is found to be much smaller for small engine particles than that for large engine particles. The VPS instrument provides a means beyond just being a volatile particle remover; it enables a numerical definition to characterize volatile engine particles.

  12. Energy conservation potential of Portland cement particle size distribution control, Phase 2

    SciTech Connect

    Helmuth, R.A; Whiting, D.A.

    1983-01-01

    The main objectives of Phase 2 are to determine the feasibility of using cements with controlled particle size distributions (CPSD cements) in practical concrete applications, and to refine our estimates of the potential energy savings that may ensue from such use. The work in Phase 2 is divided into two main tasks, some parts of which will be carried out simultaneously: Task 1 will continue cement paste studies to optimize cement performance similar to those of Phase 1, but with particular emphasis on gypsum requirements, blended cements, and water-reducing admixtures. This task will also include preparation of sufficient CPSD cements for use in all Phase 2 work. Task 2 will be a comprehensive examination of the properties of concretes made with CPSD cements. This will include optimization of concrete mix designs to obtain the best possible performance for practical applications of both portland and blended cements. The effects of chemical admixtures and curing temperature variations will also be determined.

  13. Film model approximation for particle-diffusion-controlled binary ion exchange

    SciTech Connect

    Carta, G.; Cincotti, A.; Cao, G.

    1999-01-01

    A new rate expression for particle-diffusion-controlled ion exchange, based on an equivalent pseudosteady-state film resistance model, is developed. The rate expression approximates the electric field effects on intraparticle diffusion in spherical ion-exchangers. With regard to the prediction of batch exchange and column breakthrough curves for both irreversible and reversible processes, the model captures the essential traits of the coupled diffusion phenomenon described by the Nernst-Planck equation with results of accuracy comparable to that obtained when using the linear driving force approximation for systems with constant diffusivity. Numerical results for the exchange of two counterions of equal valence are presented as application examples for different mobility ratios and selectivity coefficients.

  14. Administration of copper oxide wire particles in a capsule or feed for gastrointestinal nematode control in goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Widespread anthelmintic resistance in small ruminants has necessitated alternative means of gastrointestinal nematode (GIN) control. The objective was to determine the effectiveness of copper oxide wire particles (COWP) administered as a gelatin capsule or in a feed supplement to control GIN in goa...

  15. Particle-in-cell simulations of electron beam control using an inductive current divider

    SciTech Connect

    Swanekamp, S. B.; Angus, J. R.; Cooperstein, G.; Ottinger, P. F.; Richardson, A. S.; Schumer, J. W.; Weber, B. V.

    2015-11-18

    Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam’s return current. The current divider concept was proposed and studied theoretically in a previous publication [Phys. Plasmas 22, 023107 (2015)] A central post carries a portion of the return current (I1) while the outer conductor carries the remainder (I2) with the injected beam current given by Ib=I1+I2. The simulations are in agreement with the theory which predicts that the total force on the beam trajectory is proportional to (I2-I1) and the force on the beam envelope is proportional to Ib. For a fixed central post, the beam trajectory is controlled by varying the outer conductor radius which changes the inductance in the return-current path. The simulations show that the beam emittance is approximately constant as the beam propagates through the current divider to the target. As a result, independent control over both the current density and the beam angle at the target is possible by choosing the appropriate return-current geometry.

  16. Particle-in-cell simulations of electron beam control using an inductive current divider

    DOE PAGES

    Swanekamp, S. B.; Angus, J. R.; Cooperstein, G.; ...

    2015-11-18

    Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam’s return current. The current divider concept was proposed and studied theoretically in a previous publication [Phys. Plasmas 22, 023107 (2015)] A central post carries a portion of the return current (I1) while the outer conductor carries the remainder (I2) with the injected beam current given by Ib=I1+I2. The simulations are in agreement with the theory which predicts that the total forcemore » on the beam trajectory is proportional to (I2-I1) and the force on the beam envelope is proportional to Ib. For a fixed central post, the beam trajectory is controlled by varying the outer conductor radius which changes the inductance in the return-current path. The simulations show that the beam emittance is approximately constant as the beam propagates throug