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1

Capture of metallic copper by high gradient magnetic separation system  

Microsoft Academic Search

Valence copper was recovered from wastewater by chemical reduction and use of a high gradient magnetic separation (HGMS) system. Ammonia (NH3) and sodium dithionate (Na2S2O4) at a molar ratio of [Cu]:[NH3]:[Na2S2O4] = 1:4:3 at pH = 9.5 were used first to chemically reduce copper ion to metallic copper; the resultant metal solids were captured in an upflowing reactor space equipped

P. K. Andy Hong

2011-01-01

2

Magnetic separation of ferrihydrite from wastewater by magnetic seeding and high-gradient magnetic separation  

Microsoft Academic Search

Ferrihydrite, a member of iron oxides family, has been used as an adsorbent for the removal of heavy metal ions from industrial wastewater. The success of the operation depends mainly on the efficient removal of ferrihydrite from the aqueous phase. Hence, the emphasis of this study was given on the separation of ferrihydrite by high-gradient magnetic separator (HGMS) to overcome

Nuray Karapinar

2003-01-01

3

Medical protein separation system using high gradient magnetic separation by superconducting magnet  

NASA Astrophysics Data System (ADS)

A high gradient magnetic separation system for medical protein using affinity magnetic nano-beads has been developed. Medical protein such as monoclonal antibody or immunoglobulin is an important substance as a medicine for cancer etc. However; the separation system of these medical protein has very low separation rate and the cost of product is extremely high. The developed system shows very high separation efficiency and can achieve low cost by large production rate compared to the system now using in this field. The system consists of a 3T superconducting magnet cooled by a cryo-cooler, a filter made of fine magnetic metal wires of about 30?m diameter and a demagnetization circuit and a liquid circulation pump for solvent containing medical protein. Affinity magnetic nano-beads is covered with the medical protein after agitation of solvent containing the protein and nano-beads, then the solvent flows through the system and the beads are trapped in the filters by high gradient magnetic field. The beads are released and flow out of the system by the AC demagnetization of the filters using LC resonance circuits after discharge of the magnet. The test results shows 97.8% of the magnetic nano-beads in pure water were captured and 94.1% of total beads were collected.

Kamioka, Y.; Agatsuma, K.; Kajikawa, K.; Ueda, H.; Furuse, M.; Fuchino, S.; Iitsuka, T.; Nakamura, S.

2014-01-01

4

Modeling high gradient magnetic separation from biological fluids.  

SciTech Connect

A proposed portable magnetic separator consists of an array of biocompatible capillary tubing and magnetizable wires immersed in an externally applied homogeneous magnetic field. While subject to the homogeneous magnetic field, the wires create high magnetic field gradients, which aid in the collection of blood-borne magnetic nanospheres from blood flow. In this study, a 3-D numerical model was created using COMSOL Multiphysics 3.2 software to determine the configuration of the wire-tubing array from two possible configurations, one being an array with rows alternating between wires and tubing, and the other being an array where wire and tubing alternate in two directions. The results demonstrated that the second configuration would actually capture more of the magnetic spheres. Experimental data obtained by our group support this numerical result.

Bockenfeld, D.; Chen, H.; Rempfer, D.; Kaminski, M. D.; Rosengart, A. J.; Chemical Engineering; Illinois Inst. of Tech.; Univ. of Chicago, Pritzker School of Medicine

2006-01-01

5

High gradient magnetic separation of motile and non-motile magnetotactic bacteria  

Microsoft Academic Search

Motile magnetotactic bacteria are normally separated from a solution by applying a low intensity (mT) orientating magnetic field. This constrains the bacteria to swim in the required direction. High gradient magnetic separation (HGMS) is a well established method for the extraction of magnetic particles from solutions. This paper reports on the separation properties of both motile and non-motile magnetotactic bacteria

A. S. Bahaj; P. A. B. James; F. D. Moeschler

1996-01-01

6

Microfabricated magnetic sifter for high-throughput and high-gradient magnetic separation  

NASA Astrophysics Data System (ADS)

A microfabricated magnetic sifter has been designed and fabricated for applications in biological sample preparation. The device enables high-throughput, high-gradient magnetic separation of magnetic nanoparticles by utilizing columnar fluid flow through a dense array (˜5000/mm 2) of micropatterned slots in a magnetically soft membrane. The potential of the sifter for separation of magnetic nanoparticles conjugated with capture antibodies is demonstrated through quantitative separation experiments with CD138-labeled MACS nanoparticles. Capture efficiencies ranging from 28% to 37% and elution efficiencies greater than 73% were measured for a single pass through the sifter.

Earhart, Christopher M.; Wilson, Robert J.; White, Robert L.; Pourmand, Nader; Wang, Shan X.

2009-05-01

7

High gradient magnetic separation of iron oxide minerals from soil clays  

E-print Network

HIGH GRADIENT MAGNETIC SEPARATION OF IRON OXIDE MINERALS FROM SOIL CLAYS A Thesis by DARRELL GENE SCHULZE Submitted to the Graduate College of Texas AIM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1977 Major Subject: Soil Science HIGH GRADIENT MAGNETIC SEPARATION OF IRON OXIDE MINERALS FROM SOIL CLAYS A Thesis DARRELL GENE SCHULZE Approved as to style and content by: (Chairman of C ittee) epartm t) j (Member) (Membe December 1977...

Schulze, Darrell Gene

1977-01-01

8

HIGH-GRADIENT MAGNETIC SEPARATION FOR REMOVAL OF SULFUR FROM COAL  

EPA Science Inventory

The report gives results of a thorough physical, chemical, and magnetic characterization of a Pennsylvania coal from the Upper Freeport seam. The powdered coal was then subjected to high-gradient magnetic separations, as a function of magnetic field and fluid velocity, in both a ...

9

A novel high-gradient magnetic separator (HGMS) design for biotech applications  

Microsoft Academic Search

A novel high-gradient magnetic separator (HGMS) has been designed to meet the strong requirements of biotech processes to grant high product yield, efficient cleanability and low operating costs. The novel design using a rotary permanent magnet leads to an \\

C. Hoffmann; M. Franzreb; W. H. Holl

2002-01-01

10

APPLICATION OF HIGH-GRADIENT MAGNETIC SEPARATION TO FINE PARTICLE CONTROL  

EPA Science Inventory

The report gives results of an assessment of the potential use of high-gradient magnetic separation (HGMS) as a means of collecting gas stream particulates. The assessment included both experiments and analyses of theoretical models. Phase I included evaluations of theoretical ex...

11

Development of high-gradient and open-gradient magnetic separation  

SciTech Connect

This paper was prepared: to review the accomplishments in both high-gradient magnetic separation (HGMS) and open-gradient magnetic separation (OGMS) by the Oak Ridge National Laboratory (ORNL) group during the past three years; to show, through the medium of motion pictures, the operation of the various separation methods and devices used and developed; to show qualitative results of the separation performed; and to make available, to those interested, detailed reports of the experimental procedures and the resulting data. The qualitative separation of pyritic sulfur and ash forming minerals from fine coal by high gradient magnetic separation has been demonstrated at feed rates up to one ton per hour, and in a machine that is commercially produced in sizes for feed rates up to several hundred tons per hour. The quantitative separation of pyritic sulfur and ash forming minerals from fine coal by free fall open gradient magnetic separation has been demonstrated at a laboratory scale and at 300 kg per hour in a solenoidal magnet configuration. A magnet modeling analysis has shown that an optimum magnet can be designed with practical physical constraints which can generate separating forces two to three times those of the existing solenoidal configuration and with a large processing capacity. The analytical predictions of the behavior of particles traversing these separating forces have been experimentally confirmed within 15% in existing magnets.

Hise, E C

1981-01-01

12

Application of high temperature superconductors to high-gradient magnetic separation  

SciTech Connect

High Gradient Magnetic Separation (HGMS) is a powerful technique which can be used to separate widely dispersed contaminants from a host material, This technology can separate magnetic solids from other solids, liquids or gases. As the name implies HGMS uses large magnetic field gradients to separate ferromagnetic and paramagnetic particles. HGMS separators usually consist of a high-field solenoid magnet, the bore of which contains a fine-structured, ferromagnetic matrix material. The matrix material locally distorts the magnetic field and creates large field gradients in the vicinity of the matrix elements. These elements then become trapping sites for magnetic particles and are the basis for the magnetic separation. In this paper we discuss the design and construction of a prototype HGMS unit using a magnet made with high temperature superconductors (HTS). The prototype consists of an outer vacuum vessel which contains the HTS solenoid magnet The magnet is surrounded by a thermal radiation shield and multilayer insulation (MLI) blankets. The magnet, thermal shield and current leads all operate in a vacuum and are cooled by a cryocooler. High temperature superconducting current leads are used to reduce the heat leak from the ambient environment to the HTS magnet.

Daugherty, M.A.; Prenger, F.C.; Hill, D.D.; Daney, D.E.; Worl, L.W.; Schake, A.R.; Padilla, D.D.

1994-06-01

13

High gradient magnetic separation of a biologically produced FeS adsorbent using sulfate reducing bacteria  

SciTech Connect

A High Gradient Magnetic Separation (HGMS) technique has been used to selectively recover biologically produced iron sulfide (FeS) particles with adsorbed heavy metal ions, from a soil remediation effluent stream. The HGMS system has been optimized and its performance investigated as a function of the magnetic field, flow rate and concentration of biological particles, with time. Results have shown that an efficiency of over 95% can be obtained, proving that HGMS is a valuable method for the concentration of heavy metal contaminated soils, especially when the adsorbed heavy metals are toxic and difficult to handle by other means.

Coe, B.T.; Gerber, R. [Univ. of Salford (United Kingdom)] [Univ. of Salford (United Kingdom); Witts, D. [BNFL Capenhurst, Cheshire (United Kingdom). Product Development Centre] [BNFL Capenhurst, Cheshire (United Kingdom). Product Development Centre

1998-07-01

14

Coal characterization and high gradient magnetic separation studies of coal fines from Paradise, Kentucky  

SciTech Connect

Five coal slurry ponds at the TVA Paradise facility in Western Kentucky were characterized and high gradient magnetic separation (HGMS) studies were conducted on selected samples. The objective was to determine whether or not HGMS is an effective technique to remove pyritic sulfur and ash from coal fines. Lateral changes in particle size distribution within individual ponds reflect temporal changes in the hydrology within the ponds. Where material was dredged and stacked at the side of the pond, the particle size was coarser and the material was more acidic, due to oxidation of pyrite. Wet HGMS studies were conducted over a range of concentrations, and at different field strengths of up to 2 Tesla (20,000 gauss). Various matrices were used in the magnet including relatively coarse screens and fine particle size magnetic stainless steel wool. Grinding to finer particle sizes liberates the pyrite and ash-forming minerals, enhancing their separation in the magnet. At particle sizes greater than 200 mesh ( 75 micrometers) clogging occurred within the magnet when the finer wool matrix was used. Tests are currently underway at higher field strengths of 6 Tesla. By a single pass through the magnet the sulfur content of the coal fines was reduced by between 1.5 and 2% while the ash content also reduced by several percent. Additional sulfur removal could be achieved by second and third passes but the sulfur reductions were less. Excessive abundances of ash - forming minerals (above 40% ) limited the effectiveness of the magnet. A front end process (such as flotation) to remove the majority of the ash-forming minerals and provide a fine (<200 mesh) feed for the magnet, would likely enhance the effectiveness of HGMS. In this respect, HGMS may be more effective as a polishing step following more conventional coal cleaning technologies.

Harvey, C.C.; Dazhen, T.; Daniel, N. [Indiana Univ., Bloomington, IN (United States); Carson, W.R. [Tennessee Valley Authority, Chattanooga, TN (United States)

1997-07-01

15

TREATMENT OF COMBINED SEWER OVERFLOWS BY HIGH GRADIENT MAGNETIC SEPARATION. ON-SITE TESTING WITH MOBILE PILOT PLANT TRAILER  

EPA Science Inventory

Seeded water treatment using a SALA high gradient magnetic separator pilot plant system was conducted on combined sewer overflows and raw sewage at SALA Magnetics in Cambridge, MA and at on-site locations in the Boston area. Special emphasis was placed on specific design and oper...

16

Recovery of metallic copper by integrated chemical reduction and high gradient magnetic separation.  

PubMed

The recovery of metals from waste effluents is necessary for pollution prevention and sustainable practice. High gradient magnetic separation (HGMS) is seen as a viable method. We investigated the capture of valence copper from aqueous copper ion by HGMS in combination with a chemical reduction process. When a copper solution (3.9 or 15.6 mM) was exposed to excess of dithionite (mole ratio of 1:3) in the presence of ammonia (mole ratio of 4) and amended with MnCl2 (2.5 g/L) and the mixture passed through a flow reactor under a strong magnetic field (10000 Gauss), valence copper was obtained and captured in the reactor with well over 95% yields. The chemical reduction reactions were unaffected by the presence of MnCl2 while the amount of MnCl2 (0, 20 and 32 mM) has significantly varied the copper recovery efficiency, especially in the case of high initial copper ion concentration (15.6 mM). Formation of MnO2 flocs was found to have a detrimental effect on copper removal efficiency. The HGMS method offers a tool of resource recovery for copper from waste effluents. PMID:21879556

Wu, Wan-I; Panchangam, Sri Chandana; Wu, Chung-Hsin; Hong, Andy P K; Lin, Cheng-Fang

2011-01-01

17

Permanent magnet systems with strong stray magnetic fields and very high gradients for material separation  

NASA Astrophysics Data System (ADS)

The system consisting of permanent magnets of Kittel open domain structure with a mask made of thin sheets of soft magnetic material is described. The simulations showed that the maximal value of induction for system consisting of two neodymium-iron-boron magnets in presence of a mask is increased from 3 T (without a mask) up to 4 T. In this case the product BB on the distance of 0.01 mm achieves a value of 4.2 × 1011 mT2/m. The experimental device with a mask made of low carbon steel sheets is shown to be useful for separation of paramagnetic substances such as dysprosium sulfate, europium chloride and copper chloride.

Il'Yashenko, E. I.; Glebov, V. A.; Glebov, A. V.; Skjeltorp, A. T.; Johansen, T. H.

2006-05-01

18

Paramagnetic microchip for high-gradient separation of blood cell  

Microsoft Academic Search

This paper presents a magnetophoretic separation method on a chip of white blood cells from blood under continuous flow. The separation of red blood cells from the whole blood is performed using a high gradient magnetic separation method under continuous flow to trap the particles inside the device. The device is fabricated by microfabrication technology and enables to capture the

Ciprian Iliescu; Guolin Xu; Elena Barbarini; Marioara Avram; Florina S. Iliescu

2008-01-01

19

Purification of equine chorionic gonadotropin (eCG) using magnetic ion exchange adsorbents in combination with high-gradient magnetic separation.  

PubMed

Current purification of the glycoprotein equine chorionic gonadotropin (eCG) from horse serum includes consecutive precipitation steps beginning with metaphosphoric acid pH fractionation, two ethanol precipitation steps, and dialysis followed by a numerous of fixed-bed chromatography steps up to the specific activity required. A promising procedure for a more economic purification procedure represents a simplified precipitation process requiring only onethird of the solvent, followed by the usage of magnetic ion exchange adsorbents employed together with a newly designed 'rotor-stator' type High Gradient Magnetic Fishing (HGMF) system for large-scale application, currently up to 100 g of magnetic adsorbents. Initially, the separation process design was optimized for binding and elution conditions for the target protein in mL scale. Subsequently, the magnetic filter for particle separation was characterized. Based on these results, a purification process for eCG was designed consisting of (i) pretreatment of the horse serum; (ii) binding of the target protein to magnetic ion exchange adsorbents in a batch reactor; (iii) recovery of loaded functionalized adsorbents from the pretreated solution using HGMF; (iv) washing of loaded adsorbents to remove unbound proteins; (v) elution of the target protein. Finally, the complete HGMF process was automated and conducted with either multiple single-cycles or multicycle operation of four sequential cycles, using batches of pretreated serum of up to 20 L. eCG purification with yields of approximately 53% from single HGMF cycles and up to 80% from multicycle experiments were reached, with purification and concentration factors of around 2,500 and 6.7, respectively. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 31:78-89, 2015. PMID:25393845

Müller, Christine; Heidenreich, Elena; Franzreb, Matthias; Frankenfeld, Katrin

2015-01-01

20

Diffusion bonded matrix of high gradient magnetic filter  

SciTech Connect

For improving the performance of high gradient magnetic filter (HGMF) used in steel mill process waste water treatment, a new filtering medium of diffusion bonded matrix has been developed. This new matrix has an excellent high filtering efficiency for feebly paramagnetic particles, and also has strong structural stiffness that prevents the matrix from compaction and the flow-out of fine wool fractions, which are serious defects in the conventional stainless wool matrix.

Soda, F.; Ishibe, H.; Yukawa, T.

1985-03-01

21

High gradient magnetic beneficiation of dry pulverized coal via upwardly directed recirculating fluidization  

DOEpatents

This invention relates to an improved device and method for the high gradient magnetic beneficiation of dry pulverized coal, for the purpose of removing sulfur and ash from the coal whereby the product is a dry environmentally acceptable, low-sulfur fuel. The process involves upwardly directed recirculating air fluidization of selectively sized powdered coal in a separator having sections of increasing diameters in the direction of air flow, with magnetic field and flow rates chosen for optimum separations depending upon particulate size.

Eissenberg, David M. (Oak Ridge, TN); Liu, Yin-An (Opelika, AL)

1980-01-01

22

Experimental Study on Capture of PM10 Emitted from Coal Combustion with High Gradient Magnetic Field  

NASA Astrophysics Data System (ADS)

Experiments on capturing PM10 emitted from coal combustion with high gradient magnetic field were carried out for the first time. A new fluidized bed aerosol generator was developed for generating fly ash aerosol with diameter less than 10?m constantly. The variation in the particle number concentration caused by high gradient magnetic field was measured with the Electrical Low Pressure Impactor (ELPI). Fly ash particles from combustion of three kinds of coal were sampled. Particle saturation magnetic moment is 0.37emu/g, 1.25emu/g, 2.00emu/g respectively. The results show that for the particles in the size range of 0.1?m˜10?m particle capture efficiency varies from 25% to 40%. The particle with either larger or smaller size has higher capture efficiency, and the particle with medium size (1?m˜3?m) has lower capture efficiency. The particle capture efficiency rises with increase in the particle magnetization, the magnetic field gradient and the filling ratio of ferromagnetic medium, and it reduces with increase in aerosol velocity. The present study indicates that high gradient magnetic separation is an effective way to control fine particle emission from coal combustion.

Lu, Duanfeng; Zhao, Changsui; Wu, Xin; Li, Yongwang; Han, Song

2007-06-01

23

COLLECTION OF AIRBORNE PARTICLES BY A HIGH-GRADIENT PERMANENT MAGNETIC METHOD  

SciTech Connect

We report on the use of magnetic force in collection of airborne particles by a high- gradient permanent magnetic separation (HGPMS) device. Three aerosol particles of different magnetic susceptibility (NaCl, CuO, and Fe2O3) were generated in the electrical mobility size range of 10 to 200 nm and were used to study HGPMS collection. One HGPMS matrix element, made of stainless steel wool, was used in the device configuration. Three flow rates were selected to simulate the environmental wind speeds of interest to the study. Magnetic force was found to exhibit an insignificant effect on the separation of NaCl particles, even in the HGPMS configuration. Diffusion was a major mechanism in the removal of the diamagnetic particles; however, diffusion is insignificant under the influence of a high-gradient magnetic field for paramagnetic or ferromagnetic particles. The HGPMS showed high-performance collection (> 99%) of paramagnetic CuO and ferromagnetic Fe2O3 particles for particle sizes greater than or equal to 60 nm. As the wind speed increases, the influence of the magnetic force weakens, and the capability to remove particles from the gas stream diminishes. The results suggest that the HGPMS principle could be explored for development of an advanced miniaturized passive aerosol collector.

Cheng, Mengdawn [ORNL; Allman, Steve L [ORNL; Ludtka, Gerard Michael [ORNL; Avens, Larry R [ORNL

2014-01-01

24

High-gradient nanomagnets on cantilevers for sensitive detection of nuclear magnetic resonance.  

PubMed

Detection of magnetic resonance as a force between a magnetic tip and nuclear spins has previously been shown to enable sub-10 nm resolution 1H imaging. Maximizing the spin force in such a magnetic resonance force microscopy (MRFM) experiment demands a high field gradient. In order to study a wide range of samples, it is equally desirable to locate the magnetic tip on the force sensor. Here we report the development of attonewton-sensitivity cantilevers with high-gradient cobalt nanomagnet tips. The damage layer thickness and saturation magnetization of the magnetic material were characterized by X-ray photoelectron spectroscopy and superconducting quantum interference device magnetometry. The coercive field and saturation magnetization of an individual tip were quantified in situ using frequency-shift cantilever magnetometry. Measurements of cantilever dissipation versus magnetic field and tip–sample separation were conducted. MRFM signals from protons in a polystyrene film were studied versus rf irradiation frequency and tip–sample separation, and from this data the tip field and tip-field gradient were evaluated. Magnetic tip performance was assessed by numerically modeling the frequency dependence of the magnetic resonance signal. We observed a tip-field gradient ?B(z)(tip)/?z estimated to be between 4.4 and 5.4 MT m(–1), which is comparable to the gradient used in recent 4 nm resolution 1H imaging experiments and larger by nearly an order of magnitude than the gradient achieved in prior magnet-on-cantilever MRFM experiments. PMID:23033869

Longenecker, Jonilyn G; Mamin, H J; Senko, Alexander W; Chen, Lei; Rettner, Charles T; Rugar, Daniel; Marohn, John A

2012-11-27

25

High-Gradient Nanomagnets on Cantilevers for Sensitive Detection of Nuclear Magnetic Resonance  

PubMed Central

Detection of magnetic resonance as a force between a magnetic tip and nuclear spins has previously been shown to enable sub-10 nm resolution 1H imaging. Maximizing the spin force in such a magnetic resonance force microscopy (MRFM) experiment demands a high field gradient. In order to study a wide range of samples, it is equally desirable to locate the magnetic tip on the force sensor. Here we report the development of attonewton-sensitivity cantilevers with high gradient cobalt nanomagnet tips. The damage layer thickness and saturation magnetization of the magnetic material were characterized by X-ray photoelectron spectroscopy and superconducting quantum interference device magnetometry. The coercive field and saturation magnetization of an individual tip were quantified in situ using frequency-shift cantilever magnetometry. Measurements of cantilever dissipation versus magnetic field and tip-sample separation were conducted. MRFM signals from protons in a polystyrene film were studied versus rf irradiation frequency and tip-sample separation, and from this data the tip field and tip-field gradient were evaluated. Magnetic tip performance was assessed by numerically modeling the frequency dependence of the magnetic resonance signal. We observed a tip-field gradient ?Bztip??z estimated to be between 4.4 and 5.4 MT m?1, which is comparable to the gradient used in recent 4 nm resolution 1H imaging experiments and larger by nearly an order of magnitude than the gradient achieved in prior magnet-on-cantilever MRFM experiments. PMID:23033869

Longenecker, Jonilyn G.; Mamin, H. J.; Senko, Alexander W.; Chen, Lei; Rettner, Charles T.; Rugar, Daniel; Marohn, John A.

2012-01-01

26

High and ulta-high gradient quadrupole magnets  

SciTech Connect

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Brunk, W.O.; Walz, D.R.

1985-05-01

27

High and ultra-high gradient quadrupole magnets  

NASA Astrophysics Data System (ADS)

Small bore conventional dc quadrupoles with apertures from 1 to 2.578 cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e(+)/e(-) super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Brunk, W. O.; Walz, D. R.

1985-05-01

28

High and ultra-high gradient quadrupole magnets  

SciTech Connect

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Walz, D.R.; Brunk, W.O.

1985-10-01

29

Phase distribution and phase structure control through a high gradient magnetic field during the solidification process  

Microsoft Academic Search

Influence of a high gradient magnetic field on the phase distribution and phase structure has been investigated experimentally. It was found that the application of a gradient magnetic field is capable of controlling the distribution of the primary phase in alloys. As a consequence, an axial gradient magnetic field causes the primary MnBi phase in Bi–6wt.%Mn alloy and the primary

Xi Li; Zhongming Ren; Yves Fautrelle

2008-01-01

30

PILOT-SCALE FIELD TESTS OF HIGH-GRADIENT MAGNETIC FILTRATION  

EPA Science Inventory

The report gives results of using a 5100 cu m/hr mobile pilot plant to evaluate the effectiveness and economics of applying high-gradient magnetic filtration (HGMF) to particulate emission control. A 4-1/2 month test program was conducted at a Pennsylvania sintering plant to char...

31

Magnetic separation for soil decontamination  

SciTech Connect

High gradient magnetic separation (HGMS) is a physical separation process that is used to extract magnetic particles from mixtures. The technology is used on a large scale in the kaolin clay industry to whiten or brighten kaolin clay and increase its value. Because all uranium and plutonium compounds are slightly magnetic, HGMS can be used to separate these contaminants from non-magnetic soils. A Cooperative Research and Development Agreement (CRADA) was signed in 1992 between Los Alamos National Laboratory (LANL) and Lockheed Environmental Systems and Technologies Company (LESAT) to develop HGMS for soil decontamination. This paper reports progress and describes the HGMS technology.

Avens, L.R.; Worl, L.A.; deAguero, K.J.; Padilla, D.D.; Prenger, F.C.; Stewart, W.F.; Hill, D.D. (Los Alamos National Lab., NM (United States)); Tolt, T.L. (Lockheed Environmental Systems and Technologies (United States))

1993-01-01

32

Magnetic separation for soil decontamination  

SciTech Connect

High gradient magnetic separation (HGMS) is a physical separation process that is used to extract magnetic particles from mixtures. The technology is used on a large scale in the kaolin clay industry to whiten or brighten kaolin clay and increase its value. Because all uranium and plutonium compounds are slightly magnetic, HGMS can be used to separate these contaminants from non-magnetic soils. A Cooperative Research and Development Agreement (CRADA) was signed in 1992 between Los Alamos National Laboratory (LANL) and Lockheed Environmental Systems and Technologies Company (LESAT) to develop HGMS for soil decontamination. This paper reports progress and describes the HGMS technology.

Avens, L.R.; Worl, L.A.; deAguero, K.J.; Padilla, D.D.; Prenger, F.C.; Stewart, W.F.; Hill, D.D. [Los Alamos National Lab., NM (United States); Tolt, T.L. [Lockheed Environmental Systems and Technologies (United States)

1993-02-01

33

A review of conductor performance for the LARP high-gradient quadrupole magnets  

NASA Astrophysics Data System (ADS)

We summarize critical current measurements and parameterizations of the data of 112 round wires and extracted strands that were reacted with the first 17 coils for the high-gradient quadrupole (HQ) magnets for the US LHC Accelerator Research Program (LARP). We standardize the strand parameterizations and coil ‘short sample’ calculations, and demonstrate that the entire critical current database can be captured in two scaling parameters per coil. These parameters summarize the short sample performance for each coil for either HQ magnet tests, or mirror tests of individual coils. We also demonstrate that for RRP® conductors, generic strain scaling parameters can be derived for at least four substantially different wire configurations, and standardize self-field corrections for LARP. The parameterized conductor performance is used to judge the performance of the HQ magnets and mirror tests. We find that although the HQ magnets reach around 86% of their short sample limitations, they are limited by factors other than the critical current of the conductor. Individual coils in mirror tests reach up to 98% of the expected performance, and do appear limited by the critical current of the conductor. Detailed analysis of short sample performance through accurate parameterizations simplifies the accessibility of short sample data, and enables accurate judgment of magnet performance as well as conductor and cable quality.

Godeke, A.; Chlachidze, G.; Dietderich, D. R.; Ghosh, A. K.; Marchevsky, M.; Mentink, M. G. T.; Sabbi, G. L.

2013-09-01

34

Evidence of Magnetic Breakdown on the Defects With Thermally Suppressed Critical Field in High Gradient SRF Cavities  

SciTech Connect

At SRF 2011 we presented the study of quenches in high gradient SRF cavities with dual mode excitation technique. The data differed from measurements done in 80's that indicated thermal breakdown nature of quenches in SRF cavities. In this contribution we present analysis of the data that indicates that our recent data for high gradient quenches is consistent with the magnetic breakdown on the defects with thermally suppressed critical field. From the parametric fits derived within the model we estimate the critical breakdown fields.

Eremeev, Grigory [JLAB; Palczewski, Ari [JLAB

2013-09-01

35

Magnetotropism of roots and structure of their statocytes exposed to high gradient magnetic field  

NASA Astrophysics Data System (ADS)

In most living organisms gravity perception is based on the response of the gravisensing system to displacement of specific mass induced by a gravitational force The amyloplasts in higher plants are known to play the important role as the specific mass in gravisensing cells As was shown by Kuznetsov Hasenstein 1996 the high-gradient magnetic field HGMF exerts a directional ponderomotive force on such diamagnetic structures as amyloplasts This effect of the HGMF results in root curvature similar to that produced by gravity It was suggested that the HGMF could allow to imitate the effects of gravity in microgravity and or to change them in laboratory conditions correspondingly as well as to study statolith-related processes in graviperception Therefore the correlation between the direction of the ponderomotive force resulting in statolith displacements and the direction of the HGMF-induced plant curvature can be the serious argument to support this suggestion and needs the detailed structural analysis We have designed the HGMF facility that allows for generating the HGMF and analyzing its effects on higher plants roots The parameters of kinetics of Lepidium sativum L and Pisum sativum L root curvatures under both the HGMF action and gravistimulation were recorded by video system and measured by means of image analysis software The main results of the study are followings 1 the magnetotropic effect of the HGMF on root growth was found for pea and cress roots 2 the critical value of ponderomotive force that

Belyavskaya, N. A.; Polishchuk, O. V.; Kondrachuk, A. V.

36

Ultrastructure of pea and cress root statocytes exposed to high gradient magnetic field  

NASA Astrophysics Data System (ADS)

As it was demonstrated by Kuznetsov & Hasenstein (1996) the high gradient magnetic field (HGMF) can produce a ponderomotive force that results in displacements of amyloplasts and causes the root response similar to the graviresponse. It was suggested that the HGMF could allow to imitate the effects of gravity in microgravity and/or change them in laboratory conditions correspondingly, as well as to study statolith-related processes in graviperception. Therefore, the correlation between the direction of the ponderomotive force resulting in statolith displacements and the direction of the HGMF-induced plant curvature can be the serious argument to support this suggestion and needs the detailed ultrastructural analysis. Seeds of dicotyledon Pisum sativum L. cv. Damir-2 and monocotyledon Lepidium sativum L. cv. P896 were soaked and grown in a vertical position on moist filter paper in chambers at room temperature. Tips of primary roots of vertical control, gravistimulated and exposed to HGMF seedlings were fixed for electron microscopy using conventional techniques. At ultrastructural level, we observed no significant changes in the volume of the individual statocytes or amyloplasts, relative volumes of cellular organelles (except vacuoles), number of amyloplasts per statocyte or surface area of endoplasmic reticulum. No consistent contacts between amyloplasts and any cellular structures, including plasma membrane, were revealed at any stage of magneto- and gravistimulation. By 5 min after onset of magnetostimulation, amyloplasts were located along cell wall distant from magnets. In HGMF, the locations of amyloplasts in columella cells were similar to those in horizontally-oriented roots up to 1 h stimulation. In the latter case, there were sometimes cytoplasmic spherical bodies with a dense vesicle-rich cytoplasm in pea statocytes, which were absent in seedlings exposed to HGMF. In cress root statocytes, both gravi- and magnetostimulation were found to cause the appearance of significant amounts of electron-dense granules in the cytoplasm and the nucleus (particularly, in the nucleolus); the effect was most evident in HGMF. Testing the chemical composition of such deposits is going on. The data presented statocyte responses indicate similarity the effects of magneto- and gravistimulation at the ultrastructural level. Thus, the root curvature in HGMF is the plant response to displacement of amyloplasts by ponderomotive force, which can serve as tool for investigation of graviperception mechanism and can provide directional stimulus for plant growth in microgravity. (Financial support by STCU: NN-13R).

Belyavskaya, N. A.; Chernishov, V. I.; Polishchuk, O. V.; Kondrachuk, A. V.

37

Magnetic separation of uranium from magnesium fluoride  

SciTech Connect

The attraction or repulsion of particles by a magnetic gradient, based on the respective susceptibilities, provides the basis for physical separation of particles that are comprised predominantly of uranium from those that are predominantly magnesium fluoride (MgF/sub 2/). To determine the effectiveness of this approach, a bench-scale magnetic separator from the S.G. Frantz Co., Inc. was used. In the Frantz Model L-1, particles are fed through a funnel onto a vibration tray and through a magnetic field. The specific design of the Frantz magnet causes the magnetic field strength to vary along the width of the magnet, setting up a gradient. The tray in the magnetic field is split at a point about half way down its length so that the separated material does not recombine. A schematic is presented of Frantz Model L-1 CN - the same magnet configured for high gradient magnetic separation of liquid-suspended particles. Here different pole pieces create a uniform magnetic field, and stainless steel wood in the canister between the pole pieces creates the high gradient. 1 ref., 6 figs., 2 tabs.

Hoegler, J.M.

1987-01-01

38

Down-regulation of adipogenesis of mesenchymal stem cells by oscillating high-gradient magnetic fields and mechanical vibration  

NASA Astrophysics Data System (ADS)

Nowadays, the focus in medicine on molecular genetics has resulted in a disregard for the physical basis of treatment even though many diseases originate from changes in cellular mechanics. Perturbations of the cellular nanomechanics promote pathologies, including cardiovascular disease and cancer. Furthermore, whilst the biological and therapeutic effects of magnetic fields are a well-established fact, to date the underlying mechanisms remain obscure. Here, we show that oscillating high-gradient magnetic field (HGMF) and mechanical vibration affect adipogenic differentiation of mesenchymal stem cells by the transmission of mechanical stress to the cell cytoskeleton, resulting in F-actin remodelling and subsequent down-regulation of adipogenic genes adiponectin, PPAR?, and AP2. Our findings propose an insight into the regulation of cellular nanomechanics, and provide a basis for better controlled down-regulation of stem cell adipogenesis by HGMF, which may facilitate the development of challenging therapeutic strategies suitable for the remote control of biological systems.

Zablotskii, V.; Lunov, O.; Novotná, B.; Churpita, O.; Trošan, P.; HoláÅ, V.; Syková, E.; Dejneka, A.; Kubinová, Š.

2014-09-01

39

Computational modeling of magnetic nanoparticle targeting to stent surface under high gradient field  

NASA Astrophysics Data System (ADS)

A multi-physics model was developed to study the delivery of magnetic nanoparticles (MNPs) to the stent-implanted region under an external magnetic field. The model is firstly validated by experimental work in literature. Then, effects of external magnetic field strength, magnetic particle size, and flow velocity on MNPs' targeting and binding have been analyzed through a parametric study. Two new dimensionless numbers were introduced to characterize relative effects of Brownian motion, magnetic force induced particle motion, and convective blood flow on MNPs motion. It was found that larger magnetic field strength, bigger MNP size, and slower flow velocity increase the capture efficiency of MNPs. The distribution of captured MNPs on the vessel along axial and azimuthal directions was also discussed. Results showed that the MNPs density decreased exponentially along axial direction after one-dose injection while it was uniform along azimuthal direction in the whole stented region (averaged over all sections). For the beginning section of the stented region, the density ratio distribution of captured MNPs along azimuthal direction is center-symmetrical, corresponding to the center-symmetrical distribution of magnetic force in that section. Two different generation mechanisms are revealed to form four main attraction regions. These results could serve as guidelines to design a better magnetic drug delivery system.

Wang, Shunqiang; Zhou, Yihua; Tan, Jifu; Xu, Jiang; Yang, Jie; Liu, Yaling

2014-03-01

40

High gradient superconducting quadrupoles  

SciTech Connect

Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed.

Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.

1987-07-01

41

High-gradient quadrupole magnet for a polarized-beam facility  

SciTech Connect

A prototype quadrupole magnet with 2.8 m effective length is under design and construction for use in a polarized beam transport system at Fermi National Accelerator Laboratory. The operating gradient required is 50 T/m and the higher multipole error fields must not exceed a few parts in one thousand over a 10 cm diameter bore. For cryogenic efficiency the magnet will operate at 1000 amperes and a cold iron yoke will provide complete field shielding.

Smith, R.P.; Hoffman, J.A.; Kim, S.H.; Mataya, K.F.; Niemann, R.C.; Turner, L.R.

1980-01-01

42

A novel high-gradient permanent magnet for the profiling of planar films and coatings.  

PubMed

The design and construction of a low-cost, permanent magnet is described. The magnet is intended for applications which require a large static gradient, such as those for which stray field imaging or fringe field diffusometry are conventionally employed. The magnet has been designed using the scalar potential method. Particular features of the magnet include a field profile such that ||B || is constant in the horizontal plane and such that B is horizontal at the midpoint between the poles. There is a vertical, and therefore orthogonal, strong gradient, G, in ||B ||. The ratio G/ ||B || is constant within a large volume and so allows measurements at a range of gradient strengths. It is this ratio which governs the shape of the pole-pieces. The constructed magnet has a typical operating field of 0.8 T, gives a gradient of 20 Tm-1, and has a useable interpole access of 20 mm. Field plot data show values consistent with the theory. In particular ||B || has a curvature of less than +/-5 microm over a 5 x 5 mm area at the target field. The magnet is most suitable for the one-dimensional profiling of thin planar samples. As an example of the magnet's use, a profile of a sandwich structure made of several polymer layers is shown. In addition, a set of one-dimensional profiles of an alkyd coating, recorded during solvent loss and cross-linking, is presented. This example demonstrates quantitative T2 measurements at a resolution of 6.5 microm across a 70-microm-thick film. PMID:10388588

Glover, P M; Aptaker, P S; Bowler, J R; Ciampi, E; McDonald, P J

1999-07-01

43

Magnetic separation using superconducting magnets  

Microsoft Academic Search

Since the 1970s, magnetic separation has been increasingly used for purification of liquids, such as heavy-metal ion removal from laboratory waste water, purification of kaolin clay in the paper-coating industry, waste water recycling in the steel industry, and recycling of glass grinding sludge in cathode-ray tube polishing factories. In the 1980s, large superconducting magnets were adopted for the field coils

Takeshi Ohara; Hiroaki Kumakura; Hitoshi Wada

2001-01-01

44

Magnetophoretic velocimetry of manganese(II) in a single microdroplet in a flow system under a high gradient magnetic field generated with a superconducting magnet.  

PubMed

An experimental system for magnetophoretic velocimetry, which could determine the volume magnetic susceptibility of a single particle dispersed in a liquid phase from a magnetophoretic velocity, has been developed. A micrometer-sized high-gradient magnetic field could be generated in a capillary by a pair of iron pole pieces in a superconducting magnet (10 T). The magnetophoretic behavior of a single particle in a capillary flow system was investigated under the inhomogeneous magnetic field. From the magnetophoretic velocity of a polystyrene latex particle dispersed in a MnCl2 aqueous solution, the product of the magnetic flux density and the gradient, B(dB/dx), was determined as a function of the position along the capillary. The maximum value of B(dB/dx) was 4.7 x 10(4) T2 m(-1), which was approximately 100 times higher than that obtained by two Nd-Fe-B permanent magnets (0.4 T). Organic droplets extracting manganese(II) with 2-thenoyltrifluoroacetone and tri-n-octylphosphine oxide from MnCl2 solution were used as test samples. The difference of the volume magnetic susceptibility between the droplet and the medium could be determined from the magnetophoretic velocity. This method allowed us to continuously measure a volume magnetic susceptibility of 10-6 level for a picoliter droplet and to determine manganese(II) in the single droplet at the attomole level. PMID:12380826

Suwa, Masayori; Watarai, Hitoshi

2002-10-01

45

Removal of ferriferous dolomite by magnetic separation from the Egyptian Abu Tartur phosphate ore  

Microsoft Academic Search

The Abu Tartur phosphate deposit is characterized by the presence of ferriferous dolomite, containing 60 to 70% of MgO, which allows the use of magnetic separation to reduce the MgO content of certain fractions. In fact, wet magnetic separation on a High Gradient Magnetic Separator (HGMS), applied to the [210–74] and [74–38] ?m fractions, which assay, respectively, 2.6 and 5.8%

P Blazy; E. A Jdid

1997-01-01

46

Optimizing colloidal dispersity of magnetic nanoparticles based on magnetic separation with magnetic nanowires array  

NASA Astrophysics Data System (ADS)

Based on sharp geometry of Ni nanowires, we developed a novel high-gradient magnetic separator that was composed of a nanowires array and a uniform magnetic field. When suspension of magnetic nanoparticles (MNPs) flowed through it, the relatively large nanoparticles or clusters were removed from the suspension so that the size distribution can be improved. The separation resulted from magnetic force so that extra molecules or solvents were unnecessary to add. The performance was proved by scanned electron microscopy characterization and dynamic light scattering measurement. The improvement in magnetic colloidal dispersivity is important for the biomedical application of MNPs. Our results may also play a role in microfluidic application and nanoparticle-based detection.

Sun, Jianfei; He, Miaomiao; Liu, Xuan; Gu, Ning

2015-02-01

47

A high gradient and strength bioseparator with nano-sized immunomagnetic particles for specific separation and efficient concentration of E. coli O157:H7  

NASA Astrophysics Data System (ADS)

Sample pretreatment is a key to rapid screening of pathogens for prevention and control of foodborne diseases. Magnetic immunoseparation is a specific method based on antibody-antigen reaction to capture the target bacteria and concentrate them in a smaller-volume buffer. The use of nano-sized magnetic particles could improve the separation efficiency of bacteria but require much higher gradient and strength magnetic field. In this study, a strong magnetic bioseparator with a mean field strength of 1.35 T and a mean gradient of 90 T/m was developed with the use of the 30 nm and 180 nm magnetic particles to specifically separate and efficiently concentrate foodborne bacterial pathogens using Escherichia coli O157:H7 as a model bacterium. The polyclonal antibodies against E. coli were evaluated using Dot ELISA analysis for their good affinity with the target bacteria and then used to modify the surface of the magnetic nanoparticles by 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) method and streptavidin-biotin binding. The magnetic particle concentrations were optimized to be 40 ?g/ml and 100 ?g/ml for the 30 nm and 180 nm particles, respectively, the immunoreaction time was optimized to be 45 min for both sizes of particles, and the separation times were optimized to be 60 min and 2 min for the 30 nm and 180 nm particles, respectively. The total magnetic separation time was 2 h and 1 h for the 30 nm and 180 nm particles, respectively. The experimental results demonstrated that the bioseparator with the use of either 30 nm or 180 nm immunomagnetic particles could achieve a separation efficiency of >90% for E. coli O157:H7 at the concentrations ranging from 102 to 105 cfu/ml. No obvious interferences from non-target foodborne pathogens, such as SalmonellaTyphimurium and Listeria innocua, were found. For overall consideration of the consuming time, the cost, and the separation efficiency, the 180 nm magnetic particles are practical for rapid screening applications; however the 30 nm magnetic particles are preferable for specific detection applications. This immunomagnetic bioseparator can be integrated with either conventional culture methods or some rapid detection methods, such as biosensors and PCR, for more sensitive detection of foodborne pathogens.

Lin, Jianhan; Li, Min; Li, Yanbin; Chen, Qi

2015-03-01

48

Magnetic microgels, a promising candidate for enhanced magnetic adsorbent particles in bioseparation: synthesis, physicochemical characterization, and separation performance.  

PubMed

For specific applications in the field of high gradient magnetic separation of biomaterials, magnetic nanoparticle clusters of controlled size and high magnetic moment in an external magnetic field are of particular interest. We report the synthesis and characterization of magnetic microgels designed for magnetic separation purposes, as well as the separation efficiency of the obtained microgel particles. High magnetization magnetic microgels with superparamagnetic behaviour were obtained in a two-step synthesis procedure by a miniemulsion technique using highly stable ferrofluid on a volatile nonpolar carrier. Spherical clusters of closely packed hydrophobic oleic acid-coated magnetite nanoparticles were coated with cross linked polymer shells of polyacrylic acid, poly-N-isopropylacrylamide, and poly-3-acrylamidopropyl trimethylammonium chloride. The morphology, size distribution, chemical surface composition, and magnetic properties of the magnetic microgels were determined using transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. Magnetically induced phase condensation in aqueous suspensions of magnetic microgels was investigated by optical microscopy and static light scattering. The condensed phase consists of elongated oblong structures oriented in the direction of the external magnetic field and may grow up to several microns in thickness and tens or even hundreds of microns in length. The dependence of phase condensation magnetic supersaturation on the magnetic field intensity was determined. The experiments using high gradient magnetic separation show high values of separation efficiency (99.9-99.97%) for the magnetic microgels. PMID:25519891

Turcu, Rodica; Socoliuc, Vlad; Craciunescu, Izabell; Petran, Anca; Paulus, Anja; Franzreb, Matthias; Vasile, Eugeniu; Vekas, Ladislau

2015-02-01

49

Continuous magnetic separator and process  

DOEpatents

A continuous magnetic separator and process for separating a slurry comprising magnetic particles into a clarified stream and a thickened stream. The separator has a container with a slurry inlet, an overflow outlet for the discharge of the clarified slurry stream, and an underflow outlet for the discharge of a thickened slurry stream. Magnetic particles in the slurry are attracted to, and slide down, magnetic rods within the container. The slurry is thus separated into magnetic concentrate and clarified slurry. Flow control means can be used to control the ratio of the rate of magnetic concentrate to the rate of clarified slurry. Feed control means can be used to control the rate of slurry feed to the slurry inlet.

Oder, Robin R. (Export, PA); Jamison, Russell E. (Lower Burrell, PA)

2008-04-22

50

Tank waste remediation system milestone report magnetic separation of tank waste: Surrogate system separations report  

SciTech Connect

High-level radioactive waste (HLW) has been stored in large underground storage tanks (UST) at the US Department of Energy`s Hanford Site since 1944. More than 253,000 m{sup 3} of waste have been accumulated in 177 tanks. The waste consists of many different chemicals and are in the form of liquids, slurries, salt cakes and sludges. A magnetic separation effort at Los Alamos National Laboratory is funded through the Tank Waste Remediation System (TWRS) to explore the use of high-gradient magnetic separation (HGMS) for tank waste segregation. The concept is to concentrate into a low volume waste stream, all or most of the magnetic components, which include actinide compounds, most of the fission products and precious metals. As a first step in this process investigations were made on surrogate systems. This milestone report discusses the HGMS results on these systems.

Avens, L.R.; Worl, L.A.; Schake, A.R.; Padilla, D.D.; de Aguero, K.J.; Prenger, F.C.; Stewart, W.F.; Hill, D.D.

1994-01-14

51

High gradient directional solidification furnace  

NASA Technical Reports Server (NTRS)

A high gradient directional solidification furnace is disclosed which includes eight thermal zones throughout the length of the furnace. In the hot end of the furnace, furnace elements provide desired temperatures. These elements include Nichrome wire received in a grooved tube which is encapsulated y an outer alumina core. A booster heater is provided in the hot end of the furnace which includes toroidal tungsten/rhenium wire which has a capacity to put heat quickly into the furnace. An adiabatic zone is provided by an insulation barrier to separate the hot end of the furnace from the cold end. The old end of the furnace is defined by additional heating elements. A heat transfer plate provides a means by which heat may be extracted from the furnace and conducted away through liquid cooled jackets. By varying the input of heat via the booster heater and output of heat via the heat transfer plate, a desired thermal gradient profile may be provided.

Aldrich, B. R.; Whitt, W. D. (inventor)

1985-01-01

52

Magnetic Separation for Nuclear Material Detection and Surveillance  

SciTech Connect

A high performance superconducting magnet is being developed for particle retrieval from field collected samples. Results show that maximum separation effectiveness is obtained when the matrix fiber diameter approaches the diameter of the particles to be captured. Experimentally, the authors obtained a single particle capture limit with 0.8{micro}m PuO{sub 2} particles with dodecane as a carrier fluid. The development of new matrix materials is being pursued through the controlled corrosion of stainless steel wool, or the deposition of nickel dendrites on the existing stainless steel matrix material. They have also derived a model from a continuity equation that uses empirically determined capture cross section values. This enables the prediction of high gradient magnetic separator performance for a variety of materials and applications. The model can be used to optimize the capture cross section and thus increase the capture efficiency.

Worl, L.A.; Devlin, D.; Hill, D.; Padilla, D.; Prenger, F.C.

1998-08-01

53

Method of magnetic separation and apparatus therefore  

NASA Technical Reports Server (NTRS)

An apparatus for magnetically separating and collecting particulate matter fractions of a raw sample according to relative magnetic susceptibilities of each fraction so collected is disclosed. The separation apparatus includes a splitter which is used in conjunction with a magnetic separator for achieving the desired fractionation.

Oder, Robin R. (Inventor)

1991-01-01

54

Magnetic Separator Enhances Treatment Possibilities  

NASA Technical Reports Server (NTRS)

Since the earliest missions in space, NASA specialists have performed experiments in low gravity. Protein crystal growth, cell and tissue cultures, and separation technologies such as electrophoresis and magnetophoresis have been studied on Apollo 14, Apollo 16, STS-107, and many other missions. Electrophoresis and magnetophoresis, respectively, are processes that separate substances based on the electrical charge and magnetic field of a molecule or particle. Electrophoresis has been studied on over a dozen space shuttle flights, leading to developments in electrokinetics, which analyzes the effects of electric fields on mass transport (atoms, molecules, and particles) in fluids. Further studies in microgravity will continue to improve these techniques, which researchers use to extract cells for various medical treatments and research.

2008-01-01

55

A fully integrated micromachined magnetic particle separator  

Microsoft Academic Search

A prototype micromachined magnetic particle separator that can separate magnetic particles from suspended liquid solutions has been realized on a silicon wafer. The requisite magnetic field gradients are generated by integrated inductive components in place of permanent magnets, which yields several advantages in design flexibility, compactness, electrical and optical monitoring, and integration feasibility (thus enabling mass production). Preliminary experiments have

Chong H. Ahn; Mark G. Allen; W. Trimmer; Yong-Nam Jun; S. Erramilli

1996-01-01

56

Superconducting discs as permanent magnets for magnetic separation  

Microsoft Academic Search

Magnetic separation is used widely in the mineral processing industry to concentrate and recover valuable minerals. Superconducting discs offer the opportunity to produce stronger magnetic forces than are available from conventional permanent magnets. Permanent magnets have been used to provide fields and field gradients for drum separators in which magnetic forces are used to hold magnetisable mineral particles against the

J. H. P. Watson; I. Younas

1998-01-01

57

Magnetic separation of antibiotics by electrochemical magnetic seeding  

NASA Astrophysics Data System (ADS)

Magnetic separation of several classes of antibiotics was investigated using electrochemical magnetic seeding. Electrocoagulation with a sacrificial anode followed by addition of magnetite particles was applied for the magnetic seeding of antibiotics. With electrochemical magnetic seeding using an iron anode, tetracycline antibiotics (oxytetracycline, chlortetracycline, doxycycline and tetracycline) and cephalosporin antibiotic (cefdinir) were rapidly removed from synthetic wastewater by magnetic separation using a neodymium magnet. Iron and aluminium anodes were suitable for magnetic seeding of the antibiotics. The results indicated that the ability of antibiotics to form strong complex with iron and aluminium allowed the higher removal by magnetic separation. This method would be appropriate for rapid treatment of antibiotics in wastewater.

Ihara, I.; Toyoda, K.; Beneragama, N.; Umetsu, K.

2009-03-01

58

Nanolevel Magnetic Separation Model Considering Flow Limitations  

SciTech Connect

This work proposes an enhanced nanolevel magnetic separation model considering flow limitations using simplifying assumptions. The theoretical model builds on magnetic heteroflocculation models described in the literature and couples the magnetic and hydrodynamic forces between two spherical particles with different sizes and different magnetic properties under bulk fluid flow conditions. Separator performance figures are presented showing the relationship between input parameters such as applied magnetic field strength, flow rate, and matrix material size and composition, and output parameters such as Peclet number and capture propensity for various contaminant particle sizes. This purely predictive model work may be useful in estimating actual magnetic separator performance and serve as a starting point for experimental work or more accurate mathematical models. This work provides a simplified mathematical model to predict magnetic separator performance based on single magnetic matrix particle and single magnetic contaminant particle interactions. Local maxima, or transition points, between matrix and contaminant particle size and separator performance indicate magnetic separator performance can be optimized by the selection of appropriate magnetic matrix particle size. Evaluation of points of maximum particle capture force using the Peclet number provides limiting conditions for retention of particles under Stokes flow conditions.

Cotten, Gregory Benedict; Eldredge, H Bradley; Eldredge, H. B.

2002-01-01

59

Magnetic separation in water pollution control  

Microsoft Academic Search

Magnetic separation as applied to waterborne contaminants is successful in reducing the solids content of a water sample and in removing the dissolved orthophosphate from the aqueous slurry. The contaminants are chemically associated with a magnetic seeding material, and subsequent removal of this seed sweeps the pollutants from the system. The advantage of this form of treatment over conventional techniques

CHRISTOPHER DE LATOUR

1973-01-01

60

Magnetic separation in water pollution control - II  

Microsoft Academic Search

Magnetic separation in water purification uses a magnetically susceptible seeding material as a substrate for pollutant removal. The chemical bond between the seed and pollutant is normally achieved by the action of a chemical coagulant. There are cases, however, in which an additive is not necessary, as in the removal of algal cells from sea water. Under the proper chemical

Christopher de Latour; Henry Kolm

1975-01-01

61

Research on red mud treatment by a circulating superconducting magnetic separator.  

PubMed

Red mud (RM) accumulated over the years and caused a serious environmental problem. Iron-rich fraction separation is a cost-effective way to reduce the amount of disposal RM. A circulating high-gradient superconducting magnetic separator was produced in this work. Steel wool was filled in the circulating boxes. The boxes were connected by two chains, which moved in and out the magnetic field by a drive motor. The efficiency of iron-rich RM separation by the superconducting magnetic separator was investigated. An amount of 25% (w/w) iron-rich RM fractions with a grade of 65% were separated from the 56% iron content raw RM. The parameters of the steel wool matrix were important in controlling the iron-rich RM magnetic separation. Finer steel wool increased the iron recovery ratio, but decreased the grade of the iron-rich RM concentrates. Microscopic photographs of the RM particles showed that opaque mineral particles were enriched in the collected RM. The particle size distributions of raw, concentrate and residue RM were measured. The increased particle size of concentrate RM implied that large particles were entrapped in the steel wool matrix. PMID:24701921

Li, Yiran; Chen, Haoshu; Wang, Jun; Xu, Fengyu; Zhang, Weimin

2014-01-01

62

Recovery Improvement of Fine Magnetic Particles by Floc Magnetic Separation  

Microsoft Academic Search

The performance of floc magnetic separation (FMS) has been compared with wet high-intensity magnetic separator (WHIMS). This study was performed on low-grade iron ore slime contained 59.58% Fe with 4.57% silica and 3.78% alumina. Detailed characterization data indicated that a substantial amount of the slime was below 20 µm in size. Beneficiation studies indicated that the FMS process is effective to

Subrata Roy

2012-01-01

63

Particle acceleration at a reconnecting magnetic separator  

NASA Astrophysics Data System (ADS)

Context. While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerators. Aims: We investigate the effectiveness of separator reconnection as a particle acceleration mechanism for electrons and protons. Methods: We study the particle acceleration using a relativistic guiding-centre particle code in a time-dependent kinematic model of magnetic reconnection at a separator. Results: The effect upon particle behaviour of initial position, pitch angle, and initial kinetic energy are examined in detail, both for specific (single) particle examples and for large distributions of initial conditions. The separator reconnection model contains several free parameters, and we study the effect of changing these parameters upon particle acceleration, in particular in view of the final particle energy ranges that agree with observed energy spectra.

Threlfall, J.; Neukirch, T.; Parnell, C. E.; Eradat Oskoui, S.

2015-02-01

64

Multistage Magnetic Separator of Cells and Proteins  

NASA Technical Reports Server (NTRS)

The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to position the capture magnet above the upper cuvette into which a fraction of the sample is collected. The electronic unit includes a power switch, power-supply circuitry that accepts 110-Vac input power, an RS-232 interface, and status lights. The personal computer runs the MAGSEP software and controls the operation of the MAGSEP through the RS-232 interface. The status of the power, the translating electromagnet, the capture magnet, and the rotation of the upper plate are indicated in a graphical user interface on the computer screen.

Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

2005-01-01

65

Plasma separation from magnetic field lines in a magnetic nozzle  

NASA Technical Reports Server (NTRS)

This paper discusses conditions for separation of a plasma from the magnetic field of a magnetic nozzle. The analysis assumes a collisionless, quasineutral plasma, and therefore the results represent a lower bound on the amount of detachment possible for a given set of plasma conditions. We show that collisionless separation can occur because finite electron mass inhibits the flow of azimuthal currents in the nozzle. Separation conditions are governed by a parameter G which depends on plasma and nozzle conditions. Several methods of improving plasma detachment are presented, including moving the plasma generation zone downstream from the region of strongest magnetic field and using dual magnets to focus the plasma beam. Plasma detachment can be enhanced by manipulation of the nozzle configuration.

Kaufman, D. A.; Goodwin, D. G.; Sercel, J. C.

1993-01-01

66

Asymmetric Uncertainty Expression for High Gradient Aerodynamics  

NASA Technical Reports Server (NTRS)

When the physics of the flow around an aircraft changes very abruptly either in time or space (e.g., flow separation/reattachment, boundary layer transition, unsteadiness, shocks, etc), the measurements that are performed in a simulated environment like a wind tunnel test or a computational simulation will most likely incorrectly predict the exact location of where (or when) the change in physics happens. There are many reasons for this, includ- ing the error introduced by simulating a real system at a smaller scale and at non-ideal conditions, or the error due to turbulence models in a computational simulation. The un- certainty analysis principles that have been developed and are being implemented today do not fully account for uncertainty in the knowledge of the location of abrupt physics changes or sharp gradients, leading to a potentially underestimated uncertainty in those areas. To address this problem, a new asymmetric aerodynamic uncertainty expression containing an extra term to account for a phase-uncertainty, the magnitude of which is emphasized in the high-gradient aerodynamic regions is proposed in this paper. Additionally, based on previous work, a method for dispersing aerodynamic data within asymmetric uncer- tainty bounds in a more realistic way has been developed for use within Monte Carlo-type analyses.

Pinier, Jeremy T

2012-01-01

67

Removal of less biodegradable dissolved organic matters in water by superconducting magnetic separation with magnetic mesoporous carbon  

NASA Astrophysics Data System (ADS)

Less biodegradable dissolved organic matters in water as typified by humic substances are known as precursors of carcinogenic trihalomethanes, and are removed about 60% by current advanced water treatments. However, further increase of the removal ratio is demand. In this study, magnetic mesoporous carbon (MMPC), which can adsorb the substances physically and be efficiently collected by using superconducting high gradient magnetic separation (HGMS), has been synthesized with coconut-shell-based activated carbon and ferric nitrate solution by the gas activation method. The MMPC has the maximum magnetization value of 30.7 emu/g and an adsorption ability of 87% to 10 mg/L humic acid in a short time. The standard MMPC having a magnetization of 6.43 emu/g was able to be separated at magnetic field of 2 T. Used MMPC regained the adsorption ability to 93.1% by N 2 reactivation heat treatment. These results show promise for application of current water treatments by superconducting HGMS, which is suitable for high-speed water treatment without secondary wastes.

Kondo, K.; Jin, T.; Miura, O.

2010-11-01

68

Colloidal magnetic fluids as extractants for chemical processing applications  

E-print Network

The feasibility of using high gradient magnetic separation (HGMS) to separate the Fe?0? nanoparticles was studied in this work. We present a general model for nanoparticle capture based on calculating the limit of static ...

Moeser, Geoffrey D. (Geoffery Dawson), 1976-

2003-01-01

69

Removal of malaria-infected red blood cells using magnetic cell separators: A computational study.  

PubMed

High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1(st) -5(th) order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. PMID:22345827

Kim, Jeongho; Massoudi, Mehrdad; Antaki, James F; Gandini, Alberto

2012-02-15

70

Removal of malaria-infected red blood cells using magnetic cell separators: A computational study  

PubMed Central

High gradient magnetic field separators have been widely used in a variety of biological applications. Recently, the use of magnetic separators to remove malaria-infected red blood cells (pRBCs) from blood circulation in patients with severe malaria has been proposed in a dialysis-like treatment. The capture efficiency of this process depends on many interrelated design variables and constraints such as magnetic pole array pitch, chamber height, and flow rate. In this paper, we model the malaria-infected RBCs (pRBCs) as paramagnetic particles suspended in a Newtonian fluid. Trajectories of the infected cells are numerically calculated inside a micro-channel exposed to a periodic magnetic field gradient. First-order stiff ordinary differential equations (ODEs) governing the trajectory of particles under periodic magnetic fields due to an array of wires are solved numerically using the 1st –5th order adaptive step Runge-Kutta solver. The numerical experiments show that in order to achieve a capture efficiency of 99% for the pRBCs it is required to have a longer length than 80 mm; this implies that in principle, using optimization techniques the length could be adjusted, i.e., shortened to achieve 99% capture efficiency of the pRBCs. PMID:22345827

Kim, Jeongho; Massoudi, Mehrdad; Antaki, James F.; Gandini, Alberto

2012-01-01

71

Prediction of Separation Performance of Dry High Intensity Magnetic Separator for Processing of Para-Magnetic Minerals  

NASA Astrophysics Data System (ADS)

High intensity dry magnetic separators are gaining popularity for the separation of para-magnetic minerals due to the cost economic factor. Induced roll magnetic separator is found to be an effective dry separator for the separation of fine particles. Separation efficiency of this separator depends on mineral characteristics and the design features of equipment along with the optimization of process variables. Present investigation focuses on the prediction and validation of separation performance of minerals while treating in induced roll magnetic separator. Prediction of the separation is expressed in terms of separation angle at which a particle leaves the rotor surface by using a modified particle flow model derived by Cakir. The validation of the model is carried by capturing the particle trajectory using an image analyzer. It is found that Cakir's mathematical model produces reliable results and a new model is proposed to increase the reliability of separation angle prediction by including the particle shape factor.

Tripathy, Sunil Kumar; Singh, Veerendra; Suresh, Nikkam

2015-03-01

72

Research and Development for Ultra-High Gradient Accelerator Structures  

NASA Astrophysics Data System (ADS)

Research on the basic physics of high-gradient, high frequency accelerator structures and the associated RF/microwave technology are essential for the future of discovery science, medicine and biology, energy and environment, and national security. We will review the state-of-the-art for the development of high gradient linear accelerators. We will present the research activities aimed at exploring the basic physics phenomenon of RF breakdown. We present the experimental results of a true systematic study in which the surface processing, geometry, and materials of the structures have been varied, one parameter at a time. The breakdown rate or alternatively, the probability of breakdown/pulse/meter has been recorded for different operating parameters. These statistical data reveal a strong dependence of breakdown probability on surface magnetic field, or alternatively on surface pulsed heating. This is in contrast to the classical view of electric field dependence.

Tantawi, Sami G.; Dolgashev, Valery; Higashi, Yasuo; Spataro, Bruno

2010-11-01

73

17 GHz High Gradient Accelerator Research  

SciTech Connect

This is a report on the MIT High Gradient Accelerator Research program which has included: Operation of the 17 GHz, 25 MeV MIT/Haimson Research Corp. electron accelerator at MIT, the highest frequency, stand-alone accelerator in the world; collaboration with members of the US High Gradient Collaboration, including the design and test of novel structures at SLAC at 11.4 GHz; the design, construction and testing of photonic bandgap structures, including metallic and dielectric structures; the investigation of the wakefields in novel structures; and the training of the next generation of graduate students and postdoctoral associates in accelerator physics.

Temkin, Richard J. [MIT] [MIT; Shapiro, Michael A. [MIT] [MIT

2013-07-10

74

High-gradient continuous-casting furnace  

NASA Technical Reports Server (NTRS)

High gradient allows rapid growth rates in directionally-solidified eutectic alloys. Furnace design permits cost reductions in directional solidification process through its increased solidification rates, which reduces melt/mold interaction. It produces structural engineering materials for any application requiring properties directionally-solidified eutectic materials.

Scheuermann, C. M.; Flemings, M. C.; Neff, M. A.; Rickinson, B. A.; Young, K. P.

1979-01-01

75

High-gradient normal-conducting RF structures for muon cooling channels  

Microsoft Academic Search

We present a status report on the research and development of high-gradient normal-conducting RF structures for the ionization cooling of rations in a neutrino factory or muon collider. High-gradient RF structures are required in regions enclosed in strong focussing solenoidal magnets, precluding the application of superconducting RF technology. We propose using linear accelerating structures, with individual cells electromagnetically isolated, to

J. N. Corlett; M. A. Green; N. Hartman; A. Ladran; D. Li; R. MacGill; R. Rimmer; A. Moretti; T. Jurgens; N. Holtkamp; E. Black; D. Summers; M. Booke

2001-01-01

76

Study on magnetic separation of nanosized ferromagnetic particles  

NASA Astrophysics Data System (ADS)

In recent researches in medicine and the pharmaceutical sciences, the magnetic separation technology using nanosized ferromagnetic particle is essential. For example, in the field of cell engineering, magnetic separation of nanosized ferromagnetic particles is necessary, but separation technology of nanosized particle using magnetic force has not been established. One of the reasons is that magnetic force acting on the object particles decreases as particle diameter becomes small, and makes magnetic separation difficult. In this study, magnetic force acting on the separation object was enlarged by the combination of superconducting magnet and the filter which consists of ferromagnetic particle. As a result of particle trajectory calculation and magnetic separation experiment, it was confirmed that the ferromagnetic particles of 15nm in diameter can be trapped in the magnetic filter under an external magnetic field of 0.5T. The ferromagnetic particles of 6nm in diameter which could not be separated under the same condition could also be trapped under 2.0T of external magnetic field.

Nakao, R.; Matuo, Y.; Mishima, F.; Taguchi, T.; Nishijima, S.

2009-03-01

77

Fundamental study of phosphor separation by controlling magnetic force  

NASA Astrophysics Data System (ADS)

The phosphor wastes consist of phosphors with different emission colors, green (LAP), red (YOX), blue (BAM) and white (HP). It is required to recover and reuse the rare earth phosphors with high market value. In this study, we tried to separate the phosphor using the magnetic separation by HTS bulk magnet utilizing the differences of magnetic susceptibility by the type of phosphors. We succeeded in the successive separation of HP with low market value from YOX and BAM including the rare earth using the magnetic Archimedes method. In this method, vertical and radial components of the magnetic force were used.

Wada, Kohei; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

2013-11-01

78

Relativistic klystrons for high-gradient accelerators  

SciTech Connect

Experimental work is being performed by collaborators at LLNL, SLAC, and LBL to investigate relativistic klystrons as a possible rf power source for future high-gradient accelerators. We have learned how to overcome or previously reported problem of high power rf pulse shortening and have achieved peak rf power levels of 330 MW using an 11.4-GHz high-gain tube with multiple output structures. In these experiments the rf pulse is of the same duration as the beam current pulse. In addition, experiments have been performed on two short sections of a high-gradient accelerator using the rf power from a relativistic klystron. An average accelerating gradient of 84 MV/m has been achieved with 80-MW of rf power.

Westenskow, G.A.; Aalberts, D.P.; Boyd, J.K.; Deis, G.A.; Houck, T.L.; Orzechowski, T.J.; Ryne, R.D.; Yu, S.S. (Lawrence Livermore National Lab., CA (USA)); Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fant, K.S.; Fowkes, W.R.; Hoag, H.A.; Koontz, R.F.; Lavine, T.L.; Loew, G.A.; Miller, R.H.; Ruth, R.D.; Vlieks, A.E.; Wang, J.W. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Haimson, J.; Mecklen

1990-09-05

79

Exploration of very high gradient cavities  

SciTech Connect

Several of the 9-cell ILC cavities processed at Jlab within ongoing ILC R&D program have shown interesting behavior at high fields, such as mode mixing and sudden field emission turn-on during quench. Equipped with thermometry and oscillating superleak transducer (OST) system for quench detection, we couple our RF measurements with local dissipation measurements. In this contribution we report on our findings with high gradient SRF cavities.

Grigory Eremeev

2011-07-01

80

Magnetic separation of micro-spheres from viscous biological fluids.  

SciTech Connect

A magnetically based detoxification system is being developed as a therapeutic tool for selective and rapid removal of biohazards, i.e. chemicals and radioactive substances, from human blood. One of the key components of this system is a portable magnetic separator capable of separating polymer-based magnetic nano/micro-spheres from arterial blood flow in an ex vivo unit. The magnetic separator consists of an array of alternating and parallel capillary tubing and magnetizable wires, which is exposed to an applied magnetic field created by two parallel permanent magnets such that the magnetic field is perpendicular to both the wires and the fluid flow. In this paper, the performance of this separator was evaluated via preliminary in vitro flow experiments using a separator unit consisting of single capillary glass tubing and two metal wires. Pure water, ethylene glycol-water solution (v:v = 39:61 and v:v = 49:51) and human whole blood were used as the fluids. The results showed that when the viscosity increased from 1.0 cp to 3.0 cp, the capture efficiency (CE) decreased from 90% to 56%. However, it is still feasible to obtain >90% CE in blood flow if the separator design is optimized to create higher magnetic gradients and magnetic fields in the separation area.

Chen, H.; Kaminski, M. D.; Xianqiao, L.; Caviness, P.; Torno, M.; Rosengart, A. J.; Dhar, P.; Chemical Engineering; Univ. of Chicago Pritzker School of Medicine; Illinois Inst. of Tech.

2007-02-21

81

Gravity-enhanced magnetic (HGMS) coal cleaning  

Microsoft Academic Search

For economic and environmental reasons, precombustion magnetic coal cleaning must be performed on dry pulverized coal. Gravity-enhanced high-gradient magnetic separation (HGMS) has been successfully applied to the removal of mineral impurities from coal with a 4-T superconducting solenoid magnet. Under optimum separation conditions obtained in this study, this technique effectively cleans up to 72 wt % of the pyritic sulfur

S. Zhou; E. S. Garbett; R. F. Boucher

1996-01-01

82

Magnetic separator having a multilayer matrix, method and apparatus  

DOEpatents

A magnetic separator having multiple staggered layers of porous magnetic material positioned to intercept a fluid stream carrying magnetic particles and so placed that a bypass of each layer is effected as the pores of the layer become filled with material extracted from the fluid stream.

Kelland, David R. (Lexington, MA)

1980-01-01

83

Relativistic klystron research for high gradient accelerators  

SciTech Connect

Relativistic klystrons are being developed as a power source for high gradient accelerator applications which include large linear electron--positron colliders, compact accelerators, and FEL sources. We have attained 200MW peak power at 11.4 GHz from a relativistic klystron, and 140 MV/m longitudinal gradient in a short 11.4 GHz accelerator section. We report here on the design of our first klystrons, the results of our experiments so far, and some of our plans for the near future. 5 refs., 7 figs.

Allen, M.A.; Callin, R.S.; Deruyter, H.; Eppley, K.R.; Fowkes, W.R.; Herrmannsfeldt, W.B.; Higo, T.; Hoag, H.A.; Lavine, T.L.; Lee, T.G.

1988-06-01

84

High gradient experiments on NLCTA accelerator structures  

SciTech Connect

This paper presents new results of high-gradient studies performed on a 1.8 m traveling-wave accelerator section with detuned high-order deflecting modes. This structure was designed initially for studies of detuned structures and will be installed in the Next Linear Collider Test Accelerator (NLCTA). The paper describes the test set-up in the Accelerator Structure Test Area (ASTA) including electron gun, prebuncher, pre-accelerator, spectrometer, Faraday cups, 200 MW SLED-II power compression system, Magic-T type phase shifters and attenuators. Rf processing, detailed dark current analysis, radiation problems, and beam acceleration measurements are discussed.

Wang, J.W.; Eichner, J.P.; Fant, K.H. [and others

1996-08-01

85

ELECTRICAL AND MAGNETIC SEPARATION OF PARTICLES  

Microsoft Academic Search

Particle separation technologies have been utilized in many industrial fields, such as pigment and filler production, mineral processing, environmental protection, the food and beverage industry, and the chemical industry, as well as in biomedical application, such as cell biology, molecular genetics, biotechnological production, clinical diagnostics, and therapeutics. A lot of particle separation technologies using various mechanics in terms of the

Lin Li

2010-01-01

86

Superconducting open-gradient magnetic separation for the pretreatment of radioactive or mixed waste vitrification feeds. 1997 annual progress report  

SciTech Connect

'Vitrification has been selected as a final waste form technology in the US for long-term storage of high-level radioactive wastes (HLW). However, a foreseeable problem during vitrification in some waste feed streams lies in the presence of elements (e.g., transition metals) in the HLW that may cause instabilities in the final glass product. The formation of spinel compounds, such as Fe{sub 3}O{sub 4} and FeCrO{sub 4}, results in glass phase separation and reduces vitrifier lifetime, and durability of the final waste form. A superconducting open gradient magnetic separation (OGMS) system maybe suitable for the removal of the deleterious transition elements (e.g. Fe, Co, and Ni) and other elements (lanthanides) from vitrification feed streams due to their ferromagnetic or paramagnetic nature. The OGMS systems are designed to deflect and collect paramagnetic minerals as they interact with a magnetic field gradient. This system has the potential to reduce the volume of HLW for vitrification and ensure a stable product. In order to design efficient OGMS and High gradient magnetic separation (HGMS) processes, a fundamental understanding of the physical and chemical properties of the waste feed streams is required. Using HLW simulant and radioactive fly ash and sludge samples from the Savannah River Technology Center, Rocky Flats site, and the Hanford reservation, several techniques were used to characterize and predict the separation capability for a superconducting OGMS system.'

Doctor, R.; Nunez, L. [Argonne National Lab., IL (US); Cicero-Herman, C.A. [Westinghouse Savannah River Co., Aiken, SC (US). Savannah River Technology Center; Ritter, J.A. [Univ. of South Carolina, Columbia, SC (US). Chemical Engineering Dept.; Landsberger, S. [Univ. of Texas, Austin, TX (US). Nuclear Engineering Dept.

1997-01-01

87

High Gradient Operation with the CEBAF Upgrade RF Control System  

SciTech Connect

The CEBAF Accelerator at Jefferson Lab is presently a 6 GeV five pass electron accelerator consisting of two superconducting linacs joined by independent magnetic transport arcs. Energy will be upgraded to 12 GeV with the addition of 10 new high gradient cryomodules (17+ MV/m). The higher gradients pose significant challenges beyond what the present analog low level RF (LLRF) control systems can handle reliably; therefore, a new LLRF control system is needed. A prototype system has been developed incorporating a large FPGA and using digital down and up conversion to minimize the need for analog components. The new system is more flexible and less susceptible to drifts and component nonlinearities. Because resonance control is critical to reach high gradients quickly, the new cryomodules will include a piezoelectric tuner for each cavity, and the LLRF controls must incorporate both feedback and feed-forward methods to achieve optimal resonance control performance. This paper discusses development of the new RF system, system performance for phase and amplitude stability and resonance control under Lorentz detuning measured during recent tests on a prototype cryomodule.

J. Hovater; G. Davis; Hai Dong; Alicia Hofler; Lawrence King; John Musson; Tomasz Plawski

2006-08-16

88

Microstripes for transport and separation of magnetic particles  

PubMed Central

We present a simple technique for creating an on-chip magnetic particle conveyor based on exchange-biased permalloy microstripes. The particle transportation relies on an array of stripes with a spacing smaller than their width in conjunction with a periodic sequence of four different externally applied magnetic fields. We demonstrate the controlled transportation of a large population of particles over several millimeters of distance as well as the spatial separation of two populations of magnetic particles with different magnetophoretic mobilities. The technique can be used for the controlled selective manipulation and separation of magnetically labelled species. PMID:22655020

Donolato, Marco; Dalslet, Bjarke Thomas; Hansen, Mikkel Fougt

2012-01-01

89

High gradient lens for charged particle beam  

DOEpatents

Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

Chen, Yu-Jiuan

2014-04-29

90

Development of micro immuno-magnetic cell sorting system with lamination mixer and magnetic separator  

Microsoft Academic Search

A novel micro immuno-magnetic cell sorting system has been developed for rare cell extraction. The present system consists of a lamination mixer for labeling target cells with magnetic beads, and a separator with an embedded coil, where continuous cell separation is accomplished. We have fabricated a prototype system using soft lithography, and evaluated the separation performance. We successfully achieved the

Hiromichi Inokuchi; Yuji Suzuki; Nobuhide Kasagi

91

Apparatus and method for continuous separation of magnetic particles from non-magnetic fluids  

DOEpatents

A magnetic separator vessel (1) for separating magnetic particles from non-magnetic fluid includes a separation chamber having an interior and exterior wall, a top and bottom portion; a magnet (3) having first and second poles (2) positioned adjacent to the exterior wall, wherein the first pole is substantially diametrically opposed to the second pole; a inlet port (5) is directed into the top portion of the separation chamber, wherein the inlet port (5) is positioned adjacent to one of the first and second poles (2), wherein the inlet port (5) is adapted to transfer a mixture into the separation chamber; an underflow port (6) in communication with the bottom portion, wherein the underflow port (6) is adapted to receive the magnetic particles; and an overflow port (9) in communication with the separation chamber, wherein the overflow port (9) is adapted to receive the non-magnetic fluid.

Oder, Robin R. (Export, PA); Jamison, Russell E. (Lower Burrell, PA)

2010-02-09

92

Rare Cell Separation and Analysis by Magnetic Sorting  

PubMed Central

Summary The separation and or isolation of rare cells using magnetic forces is commonly used and growing in use ranging from simple sample prep for further studies to a FDA approved, clinical diagnostic test. This grown is the result of both the demand to obtain homogeneous rare cells for molecular analysis and the dramatic increases in the power of permanent magnets that even allow the separation of some unlabeled cells based on intrinsic magnetic moments, such as malaria parasite-infected red blood cells. PMID:21812408

Zborowski, Maciej; Chalmers, Jeffrey J.

2011-01-01

93

Rare cell separation and analysis by magnetic sorting.  

PubMed

The separation and or isolation of rare cells using magnetic forces are commonly used and growing in use ranging from simple sample prep for further studies to a FDA approved, clinical diagnostic test. This growth is the result of both the demand to obtain homogeneous rare cells for molecular analysis and the dramatic increases in the power of permanent magnets that even allow the separation of some unlabeled cells based on intrinsic magnetic moments, such as malaria parasite-infected red blood cells. PMID:21812408

Zborowski, Maciej; Chalmers, Jeffrey J

2011-11-01

94

Development of magnetic separation methods of analysis: magnetic field flow fractionation  

E-print Network

DEVELOPMENT OF MAGNETIC SEPARATION METHODS OF ANALYSIS: MAGNETIC FIELD FLOW FRACTIONATION A Thesis by JAIME GARCIA-RAMIREZ Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1980 Major Subject: Chemistry DEVELOPMENT OF MAGNETIC SEPARATION METHODS OF ANALYSIS: MAGNETIC FIELD FLOW FRACTIONATION A Thesis by JAIME GARCIA-RAMIREZ Approved as to style and content by: (Chairman of Committee) 1...

Garcia-Ramirez, Jaime

1980-01-01

95

Development of a high gradient quadrupole for the LHC interaction regions  

Microsoft Academic Search

A collaboration of Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory is engaged in the design of a high gradient quadrupole suitable for use in the LHC interaction regions. The cold iron design incorporates a two-layer, cos(2?) coil geometry with a 70 mm aperture operating in superfluid helium. This paper summarizes the progress on a magnetic, mechanical and thermal

R. Bossert; S. Feher; S. A. Gourlay; T. Heger; Y. Huang; J. Kerby; M. J. Lamm; P. J. Limon; P. O. Mazur; F. Nobrega; J. P. Ozelis; G. Sabbi; J. Strait; A. V. Zlobin; S. Caspi; D. Dell'orco; A. D. McInturff; R. M. Scanlan; J. M. Van Oort; R. C. Gupta

1997-01-01

96

High-gradient compact linear accelerator  

DOEpatents

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.

Carder, Bruce M. (205 Rogue River Hwy., Gold Hill, OR 97525)

1998-01-01

97

High-gradient compact linear accelerator  

DOEpatents

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

Carder, B.M.

1998-05-26

98

Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles  

PubMed Central

A linear array of Nd-Fe-B magnets has been designed and constructed in an inverted Halbach configuration for use in separating magnetic nanoparticles. The array provides a large region of relatively low magnetic field, yet high magnetic field gradient in agreement with finite element modeling calculations. The magnet assembly has been combined with a flow channel for magnetic nanoparticle suspensions, such that for an appropriate distance away from the assembly, nanoparticles of higher moment aggregate and accumulate against the channel wall, with lower moment nanoparticles flowing unaffected. The device is demonstrated for iron oxide nanoparticles with diameters of ~ 5 and 20 nm. In comparison to other approaches, the inverted Halbach array is more amenable to modeling and to scaling up to preparative quantities of particles. PMID:25382864

Ijiri, Y.; Poudel, C.; Williams, P.S.; Moore, L.R.; Orita, T.; Zborowski, M.

2014-01-01

99

Process to remove actinides from soil using magnetic separation  

DOEpatents

A process of separating actinide-containing components from an admixture including forming a slurry including actinide-containing components within an admixture, said slurry including a dispersion-promoting surfactant, adjusting the pH of the slurry to within a desired range, and, passing said slurry through a pretreated matrix material, said matrix material adapted to generate high magnetic field gradients upon the application of a strong magnetic field exceeding about 0.1 Tesla whereupon a portion of said actinide-containing components are separated from said slurry and remain adhered upon said matrix material is provided.

Avens, Larry R. (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Stewart, Walter F. (Las Cruces, NM); Tolt, Thomas L. (Los Alamos, NM); Worl, Laura A. (Los Alamos, NM)

1996-01-01

100

Aptamer-modified magnetic beads in affinity separation of proteins.  

PubMed

Aptamers are valuable alternative ligands for affinity separations. Here, we describe the aptamer-based affinity separation of His-tagged proteins using an aptamer directed against the His-tag. The immobilization of the aptamer to magnetic beads is described as well as the aptamer-based purification and proper methods for the characterization of the process. Moreover, indications for the transfer of the process to other aptamers are given. PMID:25749947

Zhu, Guohong; Walter, Johanna-Gabriela

2015-01-01

101

Solvent Extraction and Emulsion Separation in Magnetic Fields  

Microsoft Academic Search

In two-phase emulsion separations, it is customary to employ large settling volumes (for mixer-settling apparatus) or large centrifugal forces (for centrifugal contactors). Improvement can sometimes be achieved by using an extractant with magnetic properties in the presence of a variable field. In the work reported in this paper, two different extractants (D-2EHPA and TBP) were employed in magnetic field experiments.

W. Palyska; A. G. Chmielewski

1993-01-01

102

Separation of feeble magnetic particles with magneto-Archimedes levitation  

Microsoft Academic Search

Particles and solid substances with feeble magnetic susceptibility were levitated by magnetic fields with the aid of the “magneto-Archimedes levitation” method [Nature 393 (1998) 749]. A novel feature was found, namely that the initial particle mixture levitated underwent separation into each kind of the ingredient particle aggregates. The samples levitated were NaCl–KCl grain mixtures, and colored glass particles. The experiments

Y Ikezoe; T Kaihatsu; S Sakae; H Uetake; N Hirota; K Kitazawa

2002-01-01

103

Rapid and continuous magnetic separation in droplet microfluidic devices.  

PubMed

We present a droplet microfluidic method to extract molecules of interest from a droplet in a rapid and continuous fashion. We accomplish this by first marginalizing functionalized super-paramagnetic beads within the droplet using a magnetic field, and then splitting the droplet into one droplet containing the majority of magnetic beads and one droplet containing the minority fraction. We quantitatively analysed the factors which affect the efficiency of marginalization and droplet splitting to optimize the enrichment of magnetic beads. We first characterized the interplay between the droplet velocity and the strength of the magnetic field and its effect on marginalization. We found that marginalization is optimal at the midline of the magnet and that marginalization is a good predictor of bead enrichment through splitting at low to moderate droplet velocities. Finally, we focused our efforts on manipulating the splitting profile to improve the enrichment provided by asymmetric splitting. We designed asymmetric splitting forks that employ capillary effects to preferentially extract the bead-rich regions of the droplets. Our strategy represents a framework to optimize magnetic bead enrichment methods tailored to the requirements of specific droplet-based applications. We anticipate that our separation technology is well suited for applications in single-cell genomics and proteomics. In particular, our method could be used to separate mRNA bound to poly-dT functionalized magnetic microparticles from single cell lysates to prepare single-cell cDNA libraries. PMID:25501881

Brouzes, Eric; Kruse, Travis; Kimmerling, Robert; Strey, Helmut H

2015-01-22

104

Magnetic separation as a plutonium residue enrichment process  

SciTech Connect

We have subjected several plutonium contaminated residues to Open Gradient Magnetic Separation (OGMS) on an experimental scale. Separation of graphite, bomb reduction sand, and bomb reduction sand, and bomb reduction sand, slag, and crucible, resulted in a plutonium rich fraction and a plutonium lean fraction. The lean fraction varied between about 20% to 85% of the feed bulk. The plutonium content of the lean fraction can be reduced from about 2% in the feed to the 0.1% to 0.5% range dependent on the portion of the feed rejected to this lean fraction. These values are low enough in plutonium to meet economic discard limits and be considered for direct discard. Magnetic separation of direct oxide reduction and electrorefining pyrochemical salts gave less favorable results. While a fraction very rich in plutonium could be obtained, the plutonium content of the lean fraction was to high for direct discard. This may still have chemical processing applications. OGMS experiments at low magnetic field strength on incinerator ash did give two fractions but the plutonium content of each fraction was essentially identical. Thus, no chemical processing advantage was identified for magnetic separation of this residue. The detailed results of these experiments and the implications for OGMS use in recycle plutonium processing are discussed. 4 refs., 3 figs., 9 tabs.

Avens, L.R.; McFarlan, J.T.; Gallegos, U.F.

1989-01-01

105

Magnetic Separations with Magnetite: Theory, Operation, and Limitations  

SciTech Connect

This dissertation documents the theory development and experimental plan followed to describe how a magnetite-based column under the influence of an external magnetic field functions as a magnetic separator. Theoretical simulations predict that weekly paramagnetic particles in the sub-micron range can be magnetically separated while diamagnetic particles as large as 2 microns in diameter may pass. Magnetite-based columns were evaluated as magnetically-controllable enhanced filtration devices. There was no evidence of enhanced filtration for diamagnetic particles by the magnetite-based bed. Magnetite-based magnetic separators have proven to be effective in specific laboratory experiments, indicating a potential feasibility for scale-up operations. Column media-filter type filtration effects indicate a magnetite-based column would not be suitable for treatment of a waste stream with a high diamagnetic solids content or high volume throughput requirements. Specific applications requiring removal of sub-micron para- or ferromagnetic particles under batch or Stokes flow conditions would be most applicable.

G. B. Cotten

2000-08-01

106

Magnetically stabilized fluidized bed for gas separations: Olefin-paraffin separations by {pi}-complexation  

SciTech Connect

The feasibility of using magnetically stabilized fluidized beds (MSB) for olefin-paraffin separations by pressure swing adsorption (PSA) is studied by model simulation, and the results are compared directly with that using packed beds. The sorbent used for the separations is an Ag{sup +} exchanged resin that selectively forms {pi}-complexation bonds with olefins, with the heat of adsorption of {approximately} 10 kcal/mol. Superior separations are obtained with MSB for two reasons: high flow rates and small particle sizes that are allowed in MSBs resulting in high diffusion time constants (D{sub e}/R{sup 2}) (which are favorable for equilibrium separation). Lower temperature excursions compared to packed bed also favor the separation. The larger axial dispersion in the MSB has only minimal adverse effects on the PSA separation. For example: for a 14/86 ethane/ethylene feed mixture at the same feed throughput (120.8 L(STP))/[h (kg or sorbent)], an ethylene product at 99.9% purity is obtained at over 50% ethylene recovery from the MSBs whereas only 14% recovery at the same purity is obtained with the packed beds. Acceptable separation results are also achieved with MSBs for propane-propylene separation, but not with fixed beds.

Sikavitsas, V.I.; Yang, R.T. [State Univ. of New York, Buffalo, NY (United States). Dept. of Chemical Engineering; Burns, M.A. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Chemical Engineering; Langenmayr, E.J. [Rohm and Haas Co., Spring House, PA (United States). Corporate Exploratory Research

1995-08-01

107

Experimental investigation of magnetically actuated separation using tangential microfluidic channels and magnetic nanoparticles.  

PubMed

A novel continuous switching/separation scheme of magnetic nanoparticles (MNPs) in a sub-microlitre fluid volume surrounded by neodymium permanent magnet is studied in this work using tangential microfluidic channels. Polydimethylsiloxane tangential microchannels are fabricated using a novel micromoulding technique that can be done without a clean room and at much lower cost and time. Negligible switching of MNPs is seen in the absence of magnetic field, whereas 90% of switching is observed in the presence of magnetic field. The flow rate of MNPs solution had dramatic impact on separation performance. An optimum value of the flow rate is found that resulted in providing effective MNP separation at much faster rate. Separation performance is also investigated for a mixture containing non-magnetic polystyrene particles and MNPs. It is found that MNPs preferentially moved from lower microchannel to upper microchannel resulting in efficient separation. The proof-of-concept experiments performed in this work demonstrates that microfluidic bioseparation can be efficiently achieved using functionalised MNPs, together with tangential microchannels, appropriate magnetic field strength and optimum flow rates. This work verifies that a simple low-cost magnetic switching scheme can be potentially of great utility for the separation and detection of biomolecules in microfluidic lab-on-a-chip systems. PMID:25014081

Munir, Ahsan; Zhu, Zanzan; Wang, Jianlong; Zhou, Hong Susan

2014-06-01

108

Magnetic nano-sorbents for fast separation of radioactive waste  

SciTech Connect

In order to find a cost effective and environmentally benign technology to treat the liquid radioactive waste into a safe and stable form for resource recycling or ultimate disposal, this study investigates the separation of radioactive elements from aqueous systems using magnetic nano-sorbents. Our current study focuses on novel magnetic nano-sorbents by attaching DTPA molecules onto the surface of double coated magnetic nanoparticles (dMNPs), and performed preliminary sorption tests using heavy metal ions as surrogates for radionuclides. The results showed that the sorption of cadmium (Cd) and lead (Pb) onto the dMNP-DTPA conjugates was fast, the equilibrium was reached in 30 min. The calculated sorption capacities were 8.06 mg/g for Cd and 12.09 mg/g for Pb. After sorption, the complex of heavy elements captured by nano-sorbents can be easily manipulated and separated from solution in less than 1 min by applying a small external magnetic field. In addition, the sorption results demonstrate that dMNP-DTPA conjugates have a very strong chelating power in highly diluted Cd and Pb solutions (1-10 ?g/L). Therefore, as a simple, fast, and compact process, this separation method has a great potential in the treatment of high level waste with low concentration of transuranic elements compared to tradition nuclear waste treatment. (authors)

Zhang, Huijin [Environmental Science Program, University of Idaho, Moscow, ID 83844 (United States); Kaur, Maninder [Department of Physics, University of Idaho, Moscow, ID 83844 (United States); Qiang, You [Environmental Science Program, University of Idaho, Moscow, ID 83844 (United States); Department of Physics, University of Idaho, Moscow, ID 83844 (United States)

2013-07-01

109

Enhanced shear separation for chiral magnetic colloidal aggregates  

NASA Astrophysics Data System (ADS)

We study the designing principles of the simplest colloidal propeller, an architecture built from four identical spheres that can couple translation with rotation to produce controlled drift motion. By considering superparamagnetic beads, we show that the simultaneous action of a magnetic field and a shear flow leads to the migration of the cluster in the vorticity direction. We investigate the dependence of the migration velocity on the geometrical parameters of the cluster, and find that significant cluster separation can be achieved under the typical operation conditions of microfluidic devices. Reference: C.I. Mendoza, C.M. Marques, and F. Thalmann, "Enhanced shear separation for chiral magnetic colloidal aggregates" arXiv:1011.1488

Mendoza, Carlos; Marques, Carlos; Thalmann, Fabrice

2011-03-01

110

Phosphate removal from solution using steel slag through magnetic separation  

Microsoft Academic Search

Steel slag with magnetic separation was used to remove phosphate from aqueous solutions. The influence of adsorbent dose, pH, and temperature on phosphate removal was investigated in a series of batch experiments. Phosphate removal increased with the increasing temperature, adsorbent dose and decreased with increasing initial phosphate concentrations, while it was at its peak at pH of 5.5. The phosphate

Jibing Xiong; Zhenli He; Qaisar Mahmood; Dan Liu; Xiaoe Yang; Ejazul Islam

2008-01-01

111

Design Studies of Nb3Sn High-Gradient Quadrupole Models for LARP  

SciTech Connect

Insertion quadrupoles with large aperture and high gradient are required to achieve the luminosity upgrade goal of 10{sup 35} cm{sup -2} s{sup -1} at the Large Hadron Collider (LHC). In 2004, the US Department of Energy established the LHC Accelerator Research Program (LARP) to develop a technology base for the upgrade. Nb{sub 3}Sn conductor is required in order to operate at high field and with sufficient temperature margin. We report here on the conceptual design studies of a series of 1 m long 'High-gradient Quadrupoles' (HQ) that will explore the magnet performance limits in terms of peak fields, forces and stresses. The HQ design is expected to provide coil peak fields of more than 15 T, corresponding to gradients above 300 T/m in a 90 mm bore. Conductor requirements, magnetic, mechanical and quench protection issues for candidate HQ designs will be presented and discussed.

Sabbi, GianLuca; Andreev, Nikolai; Caspi, Shlomo; Dietderich, Daniel; Ferracin, Paolo; Ghosh, Arup; Kashikhin, Vadim; Lietzke, Al; McInturff, Alfred; Novitski, Igor; Zlobin, Alexander

2007-06-01

112

Radiolysis and hydrolysis of magnetically assisted chemical separation particles  

SciTech Connect

The magnetically assisted chemical separation (MACS) process is designed to separate transuranic (TRU) elements out of high-level waste (HLW) or TRU waste. Magnetic microparticles (1--25 {mu}m) were coated with octyl (phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP) and tested for removing TRU elements from acidic nitrate solutions. The particles were contacted with nitric acid solutions and Hanford plutonium finishing plant (PFP) simulant, irradiated with a high intensity {sup 60}Co {gamma}-ray source, and evaluated for effectiveness in removing TRU elements from 2m HNO{sub 3} solutions. The resistance of the coatings and magnetic cores to radiolytic damage and hydrolytic degradation was investigated by irradiating samples of particles suspended in a variety of solutions with doses of up to 5 Mrad. Transmission electron microscopy (TEM), magnetic susceptibility measurements, and physical observations of the particles and suspension solutions were used to assess physical changes to the particles. Processes that affect the surface of the particles dramatically alter the binding sites for TRU in solution. Hydrolysis played a larger role than radiolysis in the degradation of the extraction capacity of the particles.

Buchholz, B.A.; Nunez, L.; Vandegrift, G.F.

1995-05-01

113

One-step detection of pathogens and viruses: combining magnetic relaxation switching and magnetic separation.  

PubMed

We report a sensing methodology that combines magnetic separation (MS) and magnetic relaxation switching (MS-MRS) for one-step detection of bacteria and viruses with high sensitivity and reproducibility. We first employ a magnetic field of 0.01 T to separate the magnetic beads of large size (250 nm in diameter) from those of small size (30 nm in diameter) and use the transverse relaxation time (T2) of the water molecules around the 30 nm magnetic beads (MB30) as the signal readout of the immunoassay. An MS-MRS sensor integrates target enrichment, extraction, and detection into one step, and the entire immunoassay can be completed within 30 min. Compared with a traditional MRS sensor, an MS-MRS sensor shows enhanced sensitivity, better reproducibility, and convenient operation, thus providing a promising platform for point-of-care testing. PMID:25743636

Chen, Yiping; Xianyu, Yunlei; Wang, Yu; Zhang, Xiaoqing; Cha, Ruitao; Sun, Jiashu; Jiang, Xingyu

2015-03-24

114

Kinetic approach for the purification of nucleotides with magnetic separation.  

PubMed

The isolation of ?-nicotinamide adenine dinucleotide is of great importance since it is widely used in different scientific and technologic fields such as biofuel cells, sensor technology, and hydrogen production. In order to isolate ?-nicotinamide adenine dinucleotide, first 3-aminophenyboronic acid functionalized magnetic nanoparticles were prepared to serve as a magnetic solid support and subsequently they were used for reversible adsorption/desorption of ?-nicotinamide adenine dinucleotide in a batch fashion. The loading capacity of the 3-aminophenyboronic acid functionalized nanoparticles for ?-nicotinamide adenine dinucleotide adsorption was 13.0 ?mol/g. Adsorption kinetic and isotherm studies showed that the adsorption process followed a pseudo-second-order kinetic model and the experimental data can be represented using Langmuir isotherm model. The 3-aminophenyboronic acid functionalized magnetic nanoparticles were proposed as an alternative support for the ?-nicotinamide adenine dinucleotide purification. The results elucidated the significance of magnetic separation as a fast, relatively simple, and low-cost technique. Furthermore, the magnetic supports can be reused at least five times for purification processes. PMID:25199632

Tural, Servet; Tural, Bilsen; Ece, Mehmet ?akir; Yetkin, Evren; Özkan, Necati

2014-11-01

115

Photocatalytically active titanium dioxide nanopowders: Synthesis, photoactivity and magnetic separation  

NASA Astrophysics Data System (ADS)

Two approaches were used to obtain nanocrystalline titanium dioxide (TiO2) photocatalyst powders. Firstly, low-temperature synthesis method and secondly liquid flame spraying. The structural properties of the produced powders were determined with X-ray diffraction, transmission electron microscopy and nitrogen adsorption tests. The photocatalytic properties of the powders were studied with methylene blue (MB) discoloration tests. After discolorations tests, TiO2 was coagulated with magnetite particles using FeCl3·6 H2O at a fixed pH value. Magnetic separation of coagulated TiO2 and magnetite was carried out by a permanent magnet. The obtained results showed that the particle size of the powders synthesized at low-temperature was very small and the specific surface area high. The phase content of the powder was also shown to depend greatly on the acidity of the synthesis solution. Powder synthesized by liquid flame spraying was mixture of anatase and rutile phases with essentially larger particle size and lower specific surface area than those of low-temperature synthesized powders. The MB discoloration test showed that photocatalytic activity depends on the phase structure as well as the specific surface area of the synthesized TiO2 powder. The magnetic separation of TiO2-magnetite coagulate from solution proved to be efficient around pH:8.

Nikkanen, J.-P.; Heinonen, S.; Huttunen Saarivirta, E.; Honkanen, M.; Levänen, E.

2013-12-01

116

The Yale Gas-Filled Split Pole Magnetic Separator  

NASA Astrophysics Data System (ADS)

Design and construction of a gas-filled recoil separator is underway at the Wright Nuclear Structure Laboratory at Yale University. By filling the magnetic field region of the existing Enge Split-Pole magnet with N2 or He2 gases in the 1 to 15 mbar pressure range a gradual focussing of discrete charge states has been measured. The incident ions were ^16O and ^35,37Cl with 49 MeV and 95 MeV energies, respectively. The process is understood as a result of coalescing of trajectories of different charge states around a trajectory defined by the mean charge state (q¯) of the ion in gas. Because q¯ depends on the atomic number Z and is roughly proportional with the ion velocity, the average magnetic rigidity (B¯?=Av/q¯) is almost independent of the velocity distribution of the incident ions. The ion trajectories will be therefore be mainly determined by the mass number A and the atomic number Z of the ion. Monte Carlo simulations with the code RAYTRACE closely reproduce the experimental behavior. We plan to use the Yale Mass Separator (YaMS) for nuclear structure studies in conjunction with high efficency gamma detectors (clover detectors) for enhancing weak reaction channels and fission background reduction. Work supported by the US-DOE under contract numbers DE-FG02-91ER-40609 and DE-FG02-88ER-40417.

Cata-Danil, G.; Beausang, C. W.; Casten, R. F.; Chen, A.; Chubrich, N.; Cooper, J. R.; Krücken, R.; Liu, B.; Novak, J. R.; Visser, D.; Zamfir, N. V.

1998-10-01

117

SLIM, Short-pulse Technology for High Gradient Induction Accelerators  

SciTech Connect

A novel short-pulse concept (SLIM) suited to a new generation of a high gradient induction particle accelerators is described herein. It applies advanced solid state semiconductor technology and modern microfabrication techniques to a coreless induction method of charged particle acceleration first proven on a macro scale in the 1960's. Because this approach avoids use of magnetic materials there is the prospect of such an accelerator working efficiently with accelerating pulses in the nanosecond range and, potentially, at megahertz pulse rates. The principal accelerator section is envisioned as a stack of coreless induction cells, the only active element within each being a single, extremely fast (subnanosecond) solid state opening switch: a Drift Step Recovery Diode (DSRD). Each coreless induction cell incorporates an electromagnetic pulse compressor in which inductive energy developed within a transmission-line feed structure over a period of tens of nanoseconds is diverted to the acceleration of the passing charge packet for a few nanoseconds by the abrupt opening of the DSRD switch. The duration of this accelerating output pulse--typically two-to-four nanoseconds--is precisely determined by a microfabricated pulse forming line connected to the cell. Because the accelerating pulse is only nanoseconds in duration, longitudinal accelerating gradients approaching 100 MeV per meter are believed to be achievable without inciting breakdown. Further benefits of this approach are that, (1) only a low voltage power supply is required to produce the high accelerating gradient, and, (2) since the DSRD switch is normally closed, voltage stress is limited to a few nanoseconds per period, hence the susceptibility to hostile environment conditions such as ionizing radiation, mismatch (e.g. in medical applications the peak beam current may be low), strong electromagnetic noise levels, etc is expected to be minimal. Finally, we observe the SLIM concept is not limited to linac applications; for instance, it could be employed to both accelerate the beam and to stabilize the superbunch mode of operation in circular track machines.

Arntz, Floyd; /Diversified Tech., Bedford; Kardo-Sysoev, A.; /Ioffe Phys. Tech. Inst.; Krasnykh, A.; /SLAC

2008-12-16

118

Apparatus for magnetic separation of paramagnetic and diamagnetic material  

DOEpatents

The present invention relates to methods and apparatus for segregating paramagnetic from diamagnetic particles in particulate material and, in particular, to the open gradient magnetic separation of ash producing components and pyritic sulfur from coal. The apparatus includes a vertical cylinder and a rotatable vertical screw positioned within the cylinder, the screw having a helical blade angled downwardly and outwardly from the axis. Rotation of the vertical screw causes denser particles, which in the case of coal include pyritic sulfur and ash, which are paramagnetic, to migrate to the outside of the screw, and less dense particles, such as the low sulfur organic portion of the coal, which are diamagnetic, to migrate towards the center of the screw. A vibration mechanism attached to the screw causes the screw to vibrate during rotation, agitating and thereby accommodating further segregation of the particles. An open gradient magnetic field is applied circumferentially along the entire length of the screw by a superconducting quadrupole magnet. The open gradient magnetic field further segregates the paramagnetic particles from the diamagnetic particles. The paramagnetic particles may then be directed from the cylinder into a first storage bin, and the diamagnetic particles, which are suitable for relatively clean combustion, may be directed into a second storage bin. 5 figs.

Doctor, R.D.

1988-10-18

119

Apparatus for magnetic separation of paramagnetic and diamagnetic material  

DOEpatents

The present invention relates to methods and apparatus for segregating paramagnetic from diamagnetic particles in particulate material and, in particular, to the open gradient magnetic separation of ash producing components and pyritic sulfur from coal. The apparatus includes a vertical cylinder and a rotatable vertical screw positioned within the cylinder, the screw having a helical blade angled downwardly and outwardly from the axis. Rotation of the vertical screw causes denser particles, which in the case of coal include pyritic sulfur and ash, which are paramagnetic, to migrate to the outside of the screw, and less dense particles, such as the low sulfur organic portion of the coal, which are diamagnetic, to migrate towards the center of the screw. A vibration mechanism attached to the screw causes the screw to vibrate during rotation, agitating and thereby accommodating further segregation of the particles. An open gradient magnetic field is applied circumferentially along the entire length of the screw by a superconducting quadropole magnet. The open gradient magnetic field further segregates the paramagnetic particles from the diamagnetic particles. The paramagnetic particles may then be directed from the cylinder into a first storage bin, and the diamagnetic particles, which are suitable for relatively clean combustion, may be directed into a second storage bin.

Doctor, Richard D. (Glen Ellyn, IL)

1988-01-01

120

Apparatus for magnetic separation of paramagnetic and diamagnetic material  

DOEpatents

The present invention relates to methods and apparatus for segregating paramagnetic from diamagnetic particles in particulate material and, in particular, to the open gradient magnetic separation of ash producing components and pyritic sulfur from coal. The apparatus includes a vertical cylinder and a rotatable vertical screw positioned within the cylinder, the screw having a helical blade angled downwardly and outwardly from the axis. Rotation of the vertical screw causes denser particles, which in the case of coal include pyritic sulfur and ash, which are paramagnetic, to migrate to the outside of the screw, and less dense particles, such as the low sulfur organic portion of the coal, which are diamagnetic, to migrate towards the center of the screw. A vibration mechanism attached to the screw causes the screw to vibrate during rotation, agitating and thereby accommodating further segregation of the particles. An open gradient magnetic field is applied circumferentially along the entire length of the screw by a superconducting quadrupole magnet. The open gradient magnetic field further segregates the paramagnetic-particles from the diamagnetic particles. The paramagnetic particles may then be directed from the cylinder into a first storage bin, and the diamagnetic particles, which are suitable for relatively clean combustion, may be directed into a second storage bin. 5 figs.

Doctor, R.D.

1986-07-24

121

Experimental and theoretical investigation of high gradient acceleration  

SciTech Connect

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. Experimental and Theoretical Investigations of High Gradient Acceleration.'' This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders. This report is organized as follows. The development of an rf gun design and research progress on the picosecond laser system is summarized in Sec. 2, the status of the studies of the LBL/Haimson high gradient structure, using a 50 MW free-electron laser is summarized in Sec. 3, and theoretical research progress is described in Sec. 4. Supporting material is contained in Appendices A-G.

Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R.J.; Wurtele, J.S.

1992-02-01

122

Primary beneficiation of tantalite using magnetic separation and acid leaching  

NASA Astrophysics Data System (ADS)

Primary beneficiation was successfully performed prior to dissolution of manganotantalite (sample A) and ferrotantalite (sample C) samples obtained from two different mines in the Naquissupa area, Mozambique. Magnetic separation removed the majority of iron and titanium, whereas H2SO4 leaching removed a large portion of thorium and uranium in these samples. Analytical results indicated that 64.14wt% and 72.04wt% of the total Fe and Ti, respectively, and ˜2wt% each of Nb2O5 and Ta2O5 were removed from sample C (ferrotantalite) using the magnetic separation method, whereas only 9.64wt% and 8.66wt% of total Fe2O3 and TiO2, respectively, and ˜2wt% each of Nb2O5 and Ta2O5 were removed from sample A (manganotantalite). A temperature of 50°C and a leaching time of 3 h in the presence of concentrated H2SO4 were observed to be the most appropriate leaching conditions for removal of radioactive elements from the tantalite ores. The results obtained for sample A under these conditions indicated that 64.14wt% U3O8 and 60.77wt% ThO2 were leached into the acidic solution, along with 4.45wt% and 0.99wt% of Nb2O5 and Ta2O5, respectively.

Nete, M.; Koko, F.; Theron, T.; Purcell, W.; Nel, J. T.

2014-12-01

123

Hydrodynamic Separation of Magnetic Particles and Magnetically-Labeled Blood Cells in an Annular Channel in a Quadrupole Magnetic Field  

NASA Astrophysics Data System (ADS)

A quadrupole magnetic field coupled with a flow in an axisymmetric annular thin channel is used for the continuous sorting of magnetic particles and of magnetically-labeled lymphocytes differing in magnetophoretic mobilities. The channel is composed of two concentric cylinders; in the thin annulus two flow splitters are placed at each extremity. The channel has two inlets and two outlets. Species and the carrier are injected at different inlets, and enriched and depleted species are recovered at both outlets. In order to evaluate the performance and to improve separations, we have used the pulse injection technique, common to chromatography. We investigated three different types of magnetic beads, and we have performed analyses of CD34+ magnetically labeled cells. The experimental results are compared with a theoretical model, and the validated model is then used for predicting the separator performance under various operating conditions.

Hoyos, Mauricio; Moore, Lee; McCloskey, Kara; Nakamura, Masayuki; Chalmers, Jeffrey J.; Zborowski, Maciej

1999-11-01

124

Parallel algorithm for mass transfer simulations of weakly-magnetic nanoparticles  

Microsoft Academic Search

We present a parallel algorithm for the simulation of mass transfer of weakly-magnetic nanoparticles in high gradient magnetic separation. The transport phenomena of weakly-magnetic nanoparticles in regions around a ferromagnetic long cylindrical wire in static fluid is considered. The normalized continuity equations describing the dynamics of particle volume concentration are solved numerically by using finite difference method. Parallel simulation is

Kanok Hournkumnuard; Chantana Phongpensri

2009-01-01

125

High-gradient two-beam accelerator structure  

Microsoft Academic Search

A novel cavity structure is described that could be the basis for a two-beam, high-gradient, accelerator. Versions of the structure could be used for acceleration of beams of electrons, positrons, muons, protons, or heavier ions; with either electron or proton drive beams. The structure embodies cavities that are excited in several harmonically related eigenmodes, such that rf fields reach their

S. Yu Kazakov; S. V. Kuzikov; Y. Jiang; J. L. Hirshfield

2010-01-01

126

Second generation high gradient quadrupoles for the LHC interaction regions  

Microsoft Academic Search

Conceptual designs of large-aperture high-gradient Nb3Sn quadrupoles, suitable for use in a second generation LHC interaction region, are presented. A quadrupole with a 90 mm coil aperture and the same 200 T\\/m gradient as in the current LHC IR is technically feasible and would allow ?*=0.25 in to be achieved, doubling the LHC luminosity

T. Sen; J. Strait; A. V. Zlobin

2001-01-01

127

ULTRA-HIGH GRADIENT COMPACT S-BAND ACCELERATING STRUCTURE*  

E-print Network

frequencies is not practical due to the lack of industrially available high peak power RF sources in X-band Accelerator) S- band accelerating structure operating in the pi-mode at 2.856 GHz, where RF power sources successful high gradient operation of X-band (11.4 GHz) and Ku-band (17 GHz) [5,6]. These efforts, without

Brookhaven National Laboratory

128

Study on magnetic separation for decontamination of cesium contaminated soil by using superconducting magnet  

NASA Astrophysics Data System (ADS)

The accident of Fukushima Daiichi nuclear power plant caused the diffusion of radioactive cesium over the wide area. We examined the possibility of applying magnetic separation method using the superconducting magnet, which can process a large amount of the soil in high speed, to the soil decontamination and volume reduction of the radioactive cesium contaminated soil. Clay minerals are classified as 2:1 and 1:1 types by the difference of their layer structures, and these types of minerals are respectively paramagnetic and diamagnetic including some exception. It is known that most of the radioactive cesium is strongly adsorbed on the clay, especially on 2:1 type clay minerals. It is expected that the method which can separate only 2:1 type clay minerals selectively from the mixture clay minerals can enormously contribute to the volume reduction of the contaminated soil. In this study, the components in the clay before and after separation were evaluated to estimate the magnetic separation efficiency by using X-ray diffraction. From the results, the decontamination efficiency and the volume reduction ratio were estimated in order to examine the appropriate separation conditions for the practical decontamination of the soil.

Igarashi, Susumu; Nomura, Naoki; Mishima, Fumihito; Akiyama, Yoko

2014-09-01

129

Magnetic Separation and Magnetic Properties of Low-Grade Manganese Carbonate Ore  

NASA Astrophysics Data System (ADS)

The relation between the magnetic separation behavior and magnetic properties of a low-grade manganese ore was analyzed before and after treatment by direct reduction with coal. It was found that raw ore with an initial average grade of 10.39% Mn and consisting of diamagnetic and paramagnetic minerals can be concentrated by high-intensity magnetic separation to produce a salable product with a grade of 22.75% Mn and a recovery of 89.88%. In contrast, direct reduction of the ore results in a new Mn-Fe oxide phase formed with a combination of ferromagnetic and paramagnetic properties, thereby increasing the magnetic susceptibilities of the ore by almost two orders of magnitude. The grade of Mn for the roasted ore could only be concentrated to 15.49% with a recovery of 66.67%. Therefore, it is concluded that the low-grade manganese ores with antiferromagnetic and paramagnetic (or diamagnetic, but not strongly ferromagnetic) properties could be efficiently beneficiated via high-intensity magnetic separation.

Wu, Y.; Shi, B.; Ge, W.; Yan, C. J.; Yang, X.

2015-02-01

130

The Development of the Separation Apparatus of Phosphor by Controlling the Magnetic Force  

NASA Astrophysics Data System (ADS)

The phosphor wastes contain the multiple kinds of rare-earth phosphors with high market value. Because of increasing demand for rare-earth, the technique to recover and reuse the rare-earth in the phosphor wastes is required. In this study, we focused on the difference of physical property such as magnetic susceptibility and density for each type of phosphor and tried to separate and recover the phosphors by using the magnetic separation technique utilizing the difference of the traction force to the magnet acting on the particles. Magneto-Archimedes method is method separation technique utilizi g the difference of magnetic susceptibility and density. We developed the magnetic separation apparatus by applying this technique. To develop the practical separation apparatus, the continuous process is required. Hence the fundamental experiment utilizing High Temperature Superconducting (HTS) Bulk Magnet which can generate the strong magnetic force was conducted. As a result, we succeeded the continuous separation of the phosphor wastes.

Wada, K.; Mishima, F.; Akiyama, Y.; Nishijima, S.

131

Demonstration of magnetically activated and guided isotope separation  

NASA Astrophysics Data System (ADS)

Enriched isotopes are widely used in medicine, basic science and energy production, and the need will only grow in the future. The main method for enriching stable isotopes today, the calutron, dates back over eighty years and has an uncertain future, creating an urgent need, especially in nuclear medicine. We report here the experimental realization of a general and efficient method for isotope separation that presents a viable alternative to the calutron. Combining optical pumping and a unique magnet geometry, we observe substantial depletion of Li-6 throughput in a lithium atomic beam produced by an evaporation source over a range of flux. These results demonstrate the viability of our method to yield large degrees of enrichment in a manner that is amenable to industrial scale-up and the production of commercially relevant quantities.

Mazur, Thomas R.; Klappauf, Bruce; Raizen, Mark G.

2014-08-01

132

Magnetic separation - Advanced nanotechnology for future nuclear fuel recycle  

SciTech Connect

The unique properties of magnetic nanoparticles (MNPs), such as their extremely small size and high surface area to volume ratio, provide better kinetics for the adsorption of metal ions from aqueous solutions. In this work, we demonstrated the separation of minor actinides using complex conjugates of MNPs with diethylenetriamine-pentaacetic acid (DTPA) chelator. The sorption results show the strong affinity of DTPA towards Am (III) and Pu (IV) by extracting 97% and 80% of actinides, respectively. It is shown that the extraction process is highly dependent on the pH of the solution. If these long-term heat generating actinides can be efficiently removed from the used fuel raffinates, the volume of material that can be placed in a given amount of repository space can be significantly increased. (authors)

Kaur, M.; Zhang, H.; Qiang, Y. [Department of Physics and Environmental Science, University of Idaho, Moscow, ID 83844 (United States); Martin, L.; Todd, T. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2013-07-01

133

Resonance Free Regions in Magnetic Scattering by Two Solenoidal Fields at Large Separation  

E-print Network

Resonance Free Regions in Magnetic Scattering by Two Solenoidal Fields at Large Separation Ivana the problem of quantum resonances in magnetic scattering by two solenoidal fields at large separation in two : Resonances for scattering by solenoidal fields Keywords : Resonances; magnetic scattering; solenoidal fields

Alexandrova, Ivana

134

Physical Coal Cleaning Of Midwestern Coals By Open-gradient Magnetic Separation  

Microsoft Academic Search

Open-Gradient Magnetic Separation (OGMS) using superconducting quadrupole magnets offers a novel beneficiation techology for removing pyritic sulfur from pulverized dry coal. It is estimated to have a power demand 75% lower than techniques using conventional electro-magnets, while achieving higher separation forces. Additionally, the system operates in a continuous mode and uses no chemicals. Because OGMS is specifically applicable to finely

R. D; C. D. Livengood

1990-01-01

135

Theoretical analysis of a new, efficient microfluidic magnetic bead separator based on magnetic structures on multiple length scales  

Microsoft Academic Search

We present a theoretical analysis of a new design for microfluidic magnetic bead separation. It combines an external array\\u000a of mm-sized permanent magnets with magnetization directions alternating between up and down with ?m-sized soft magnetic structures\\u000a integrated in the bottom of the separation channel. The concept is studied analytically for simple representative geometries\\u000a and by numerical simulation of an experimentally

Kristian Smistrup; Minqiang Bu; Anders Wolff; Henrik Bruus; Mikkel Fougt Hansen

2008-01-01

136

IMPROVEMENT OF IMMUNOMAGNETIC SEPARATION FOR ESCHERICHIA COLI O157:H7 DETECTION BY THE PICKPEN MAGNETIC PARTICLE SEPARATION DEVICE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Conventional immunomagnetic separation (IMS) procedures, which use an external magnetic source to capture magnetic particles against the side of a test tube, are labor intensive and can have poor sensitivity for the target organism due to high background microflora that is not effectively washed awa...

137

Magnetic separation studies on ferruginous chromite fine to enhance Cr:Fe ratio  

NASA Astrophysics Data System (ADS)

The Cr:Fe ratio (chromium-to-iron mass ratio) of chromite affects the production of chrome-based ferroalloys. Although the literature contains numerous reports related to the magnetic separation of different minerals, limited work concerning the application of magnetic separation to fine chromite from the Sukinda region of India to enhance its Cr:Fe ratio has been reported. In the present investigation, magnetic separation and mineralogical characterization studies of chromite fines were conducted to enhance the Cr:Fe ratio. Characterization studies included particle size and chemical analyses, X-ray diffraction analysis, automated mineral analysis, sink-and-float studies, and magnetic susceptibility measurements, whereas magnetic separation was investigated using a rare earth drum magnetic separator, a rare earth roll magnetic separator, an induced roll magnetic separator, and a wet high-intensity magnetic separator. The fine chromite was observed to be upgraded to a Cr:Fe ratio of 2.2 with a yield of 55.7% through the use of an induced roll magnetic separator and a feed material with a Cr:Fe ratio of 1.6.

Tripathy, Sunil Kumar; Banerjee, P. K.; Suresh, Nikkam

2015-03-01

138

Development of a high gradient quadrupole for the LHC Interaction Regions  

SciTech Connect

A collaboration of Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory is engaged in the design of a high gradient quadrupole suitable for use in the LHC interaction regions. The cold iron design incorporates a two-layer, cos(2{theta}) coil geometry with a 70 mm aperture operating in superfluid helium. This paper summarizes the progress on a magnetic, mechanical and thermal design that meets the requirements of maximum gradient above 250 T/m, high field quality and provision for adequate cooling in a high radiation environment.

Bossert, R.; Feher, S.; Gourlay, S.A. [and others

1997-04-01

139

Experimental and theoretical investigation of high gradient acceleration  

SciTech Connect

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-AC02-91-ER40648, Experimental and Theoretical Investigations of High Gradient Acceleration''. This grant supports three research tasks: Task A consists of the design, fabrication and testing of a 17GHz RF photocathode gun, which can produce 2ps electron pulses with up to 1nC of charge at 2MeV energy and at a 1OHz repetition rate. Task B supports the testing of high gradient acceleration at 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders.

Wurtele, J.S.; Bekefi, G.; Chen, C.; Chen, S.C.; Temkin, R.J.

1993-01-01

140

SUPERCONDUCTING OPEN-GRADIENT MAGNETIC SEPARATION FOR THE PRETREATMENT OF RADIOACTIVE OR MIXED WASTE VITRIFICATION FEEDS  

EPA Science Inventory

Scientists need to gain a better understanding of the magnetic separation processes that can be used to separate deleterious constituents (crystalline, amorphous, and colloidal) in vitrification feed streams for borosilicate glass production without adding chemicals or generating...

141

Method and apparatus for separating materials magnetically. [Patent application; iron pyrite from coal  

DOEpatents

Magnetic and nonmagnetic materials are separated by passing stream thereof past coaxial current-carrying coils which produce a magnetic field wherein intensity varies sharply with distance radially of the axis of the coils.

Hise, E.C. Jr.; Holman, A.S.; Friedlaender, F.J.

1980-11-06

142

Lab on a chip for continuous-flow magnetic cell separation.  

PubMed

Separation of cells is a key application area of lab-on-a-chip (LOC) devices. Among the various methods, magnetic separation of cells utilizing microfluidic devices offers the merits of biocompatibility, efficiency, and simplicity. This review discusses the fundamental physics involved in using magnetic force to separate particles, and identifies the optimisation parameters and corresponding methods for increasing the magnetic force. The paper then elaborates the design considerations of LOC devices for continuous-flow magnetic cell separation. Examples from the recently published literature illustrate these state-of-the-art techniques. PMID:25537573

Hejazian, Majid; Li, Weihua; Nguyen, Nam-Trung

2015-02-21

143

Phosphate removal from solution using steel slag through magnetic separation.  

PubMed

Steel slag with magnetic separation was used to remove phosphate from aqueous solutions. The influence of adsorbent dose, pH, and temperature on phosphate removal was investigated in a series of batch experiments. Phosphate removal increased with the increasing temperature, adsorbent dose and decreased with increasing initial phosphate concentrations, while it was at its peak at pH of 5.5. The phosphate removal predominantly occurred through ion exchange. The specific surface area of the steel slag was 2.09m2/g. The adsorption of phosphate followed both Langmuir and Freundlich isotherms. The maximum adsorption capacity of the steel slag was 5.3mgP/g. The removal rates of total phosphorus (TP) and dissolved phosphorus (DP) from secondary effluents were 62-79% and 71-82%, respectively. Due to their low cost and high capability, it was concluded that the steel slag may be an efficient adsorbent to remove phosphate both from solution and wastewater. PMID:17703877

Xiong, Jibing; He, Zhenli; Mahmood, Qaisar; Liu, Dan; Yang, Xiaoe; Islam, Ejazul

2008-03-21

144

Conjugates of Actinide Chelator-Magnetic Nanoparticles for Used Fuel Separation Technology  

SciTech Connect

The actinide separation method using magnetic nanoparticles (MNPs) functionalized with actinide specific chelators utilizes the separation capability of ligand and the ease of magnetic separation. This separation method eliminated the need of large quantity organic solutions used in the liquid-liquid extraction process. The MNPs could also be recycled for repeated separation, thus this separation method greatly reduces the generation of secondary waste compared to traditional liquid extraction technology. The high diffusivity of MNPs and the large surface area also facilitate high efficiency of actinide sorption by the ligands. This method could help in solving the nuclear waste remediation problem.

Qiang, You; Paszczynski, Andrzej; Rao, Linfeng

2011-10-30

145

Dielectric-Lined High-Gradient Accelerator Structure  

SciTech Connect

Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 dB. Experiments for studying RF high-field effects on CVD diamond samples failed to show any evidence after more than 10{sup 5} RF pulses of RF breakdown up to a tangential surface field strength of 153 MV/m; studies at higher fields were not possible due to a degradation in magnicon performance. A rebuild of the tube is underway at this writing. Computed performance for a dielectric-loaded rectangular accelerator structure (DLA) shows highly competitive properties, as compared with an existing all-metal structure. For example, comparisons were made of a DLA structure having two planar CVD diamond elements with a all-metal CERN structure HDS operating at 30 GHz. It was shown that the ratio of maximum surface electric field to accelerating field at the metal wall is only 0.35-0.4 for DLA, much smaller than the value 2.2 for HDS; and the ratio of surface magnetic field to accelerating field is 3.0 mA/V for DLA, compared with 3.45 mA/V for HDS. These values bode well for DLA in helping to avoid breakdown and to reducing pulsed surface heating and fatigue. The shunt impedance is found to be 160-175 M{Omega}/m for DLA, as compared to 99 M{Omega}/m for HDS. Conclusions are reached from this project that CVD diamond appears promising as a dielectric with a high threshold for RF breakdown, and that rectangular accelerator structures can be devised using planar CVD diamond elements that could be operated at higher acceleration gradients with low probability of RF breakdown, as compared with corresponding all-metallic structures.

Jay L. Hirshfield

2012-04-24

146

Development of magnetically separable polyaniline nanofibers for enzyme immobilization and recovery  

Microsoft Academic Search

Magnetically separable polyaniline nanofibers were synthesized using a mixture of aniline solution and iron oxide; the nanofibers comprised of crosslinked linear polymers that could be separated from the reaction solution by using magnets. The covalently attached and aggregated lipases retained a high degree of stability, were easily recovered from the enzyme solution, and could be used repeatedly. The enzyme activity

Gowoun Lee; Jungbae Kim; Jung-heon Lee

2008-01-01

147

Aligning effect of magnetic field on PDLC films during the phase separation  

Microsoft Academic Search

The results ofthe study ofthe uniaxially oriented PDLC films prepared by solvent induced phase separation (SIPS) method are presented. The samples were obtained applying a longitudinal magnetic field while the phase separation of the liquid crystal and polymer occurs due to the evaporation of common solvent from the uniform solution. In the presence of magnetic field the nematic liquid crystals

V. G. Nazarov; A. M. Parshin; V. Y. Zyryanov; V. F. Shabanov; V. I. Lapanik; V. S. Bezborodov

2007-01-01

148

Development of GM Cryocooler-Cooled Bi2223 High Temperature Superconducting Magnetic Separator  

Microsoft Academic Search

We have built a magnetic separator based on the conduction-cooled high temperature superconducting (HTS) magnet. In the paper, the high temperature superconducting magnet is made of Bi-2223 pancakes, and has inner and outer coil diameters of 120 mm and 212 mm and coil height of 111.8 mm. The magnet is conduction-cooled to generate a magnetic field of 3.22 T at

Qiuliang Wang; Yingming Dai; Xinning Hu; Shouseng Song; Yuanzhong Lei; Chuan He; Luguang Yan

2007-01-01

149

Fabrication of high gradient insulators by stack compression  

DOEpatents

Individual layers of a high gradient insulator (HGI) are first pre-cut to their final dimensions. The pre-cut layers are then stacked to form an assembly that is subsequently pressed into an HGI unit with the desired dimension. The individual layers are stacked, and alignment is maintained, using a sacrificial alignment tube that is removed after the stack is hot pressed. The HGI's are used as high voltage vacuum insulators in energy storage and transmission structures or devices, e.g. in particle accelerators and pulsed power systems.

Harris, John Richardson; Sanders, Dave; Hawkins, Steven Anthony; Norona, Marcelo

2014-04-29

150

Application of coal petrography to the evaluation of magnetically separated dry crushed coals  

SciTech Connect

In the present study the open gradient magnetic separation method has been used to beneficiate the -30 + 100 mesh fraction of two high volatile bituminous coals. The evaluation of the effectiveness of the magnetic separation for cleaning these coals is the subject of this paper. Coal petrography in combination with scanning electron microscopy and x-ray diffractometry were used to characterize the magnetically separated coal fractions. These analyses revealed that the majority of the pyrite and non-pyrite minerals were concentrated in the positive magnetic susceptibility fractions. The bulk of the starting samples (approx. 80 weight percent) were located in the negative magnetic susceptibility fractions and showed significant reductions in pyrite and non-pyritic minerals. The magnetic separation appears to effectively split the samples into relatively clean coal and refuse.

Harris, L.A.; Hise, E.C.

1981-01-01

151

A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays for cell isolation  

NASA Astrophysics Data System (ADS)

A smart fully integrated micromachined separator with soft magnetic micro-pillar arrays has been developed and demonstrated, which can merely employ one independent lab-on-chip to realize cell isolation. The simulation, design, microfabrication and test for the new electromagnetic micro separator were executed. The simulation results of the electromagnetic field in the separator show that special soft magnetic micro-pillar arrays can amplify and redistribute the electromagnetic field generated by the micro-coils. The separator can be equipped with a strong magnetic field to isolate the target cells with a considerably low input current. The micro separator was fabricated by micro-processing technology. An electroplating bath was hired to deposit NiCo/NiFe to fabricate the micro-pillar arrays. An experimental system was set up to verify the function of the micro separator by isolating the lymphocytes, in which the human whole blood mixed with Dynabeads® FlowComp Flexi and monoclonal antibody MHCD2704 was used as the sample. The results show that the electromagnetic micro separator with an extremely low input current can recognize and capture the target lymphocytes with a high efficiency, the separation ratio reaching more than 90% at a lower flow rate. For the electromagnetic micro separator, there is no external magnetizing field required, and there is no extra cooling system because there is less Joule heat generated due to the lower current. The magnetic separator is totally reusable, and it can be used to separate cells or proteins with common antigens.

Dong, Tao; Su, Qianhua; Yang, Zhaochu; Zhang, Yulong; Egeland, Eirik B.; Gu, Dan D.; Calabrese, Paolo; Kapiris, Matteo J.; Karlsen, Frank; Minh, Nhut T.; Wang, K.; Jakobsen, Henrik

2010-11-01

152

Efficiency of heavy liquid separation to concentrate magnetic particles  

Microsoft Academic Search

Low-temperature rock magnetic measurements have distinct diagnostic value. However, in most bulk marine sediments the concentration of ferrimagnetic and antiferromagnetic minerals is extremely low, so even sensitive instrumentation often responds to the paramagnetic contribution of the silicate matrix in the residual field of the magnetometer. Analysis of magnetic extracts is usually performed to solve the problems raised by low magnetic

Christine Franke; Thomas Frederichs; Mark J. Dekkers

2007-01-01

153

Separation of Uranium from Nitric and Hydrochloric-Acid Solutions with Extractant-Coated Magnetic Microparticles  

Microsoft Academic Search

The magnetically assisted chemical separation (MACS) process utilizes selective magnetic microparticle composites to separate dissolved metals from solution. In this study, MACS particles were coated with neutral and acidic organophosphorus extractants,octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), and bis(2-ethyl-hexyl)phosphoric acid (D2EHPA or HDEHP) and were evaluated for the separation of uranyl ions from nitric- and hydrochloric-acid solutions.

M. D. KAMINSKI; L. NUÑEZ

2000-01-01

154

Low magnetic-field separation system for metal-loaded magnetotactic bacteria  

Microsoft Academic Search

Magnetotactic bacteria (MTB) offer a unique approach to metal accumulation and separation from water systems. This paper proposes an integrated separator design, for the production of MTB, the metal uptake phase and their subsequent separation. Applied magnetic fields are used to orientate the bacteria, so that they swim in a direction resulting in their removal.

A. S. Bahaj; P. A. B. James; F. D. Moeschler

1998-01-01

155

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; Muggli, P.; Scott, A.; Yoder, R.; /LLNL,

2007-03-27

156

Magnetic field effect on laser isotope separation of gadolinium and zirconium  

Microsoft Academic Search

In laser isotope separation based on polarization selection rules the effect of magnetic field on isotopic selectivity was investigated. Excitation dynamics of atoms by linearly polarized lasers were numerically analyzed for J equals 2 yields 2 yields 1 yields 0 stepwise excitation under a magnetic field. Time evolution of the population in each magnetic substrate was calculated by solving the

Hideaki Niki; Iwao Kitazima

2000-01-01

157

Magnetite/CdTe magnetic-fluorescent composite nanosystem for magnetic separation and bio-imaging  

NASA Astrophysics Data System (ADS)

A new synthesis protocol is described to obtain a CdTe decorated magnetite bifunctional nanosystem via dodecylamine (DDA) as cross linker. High resolution transmission electron microscopy (HRTEM), energy-dispersive x-ray spectroscopy (EDAX), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS) and fluorescence microscopy are used to characterize the constitution, size, composition and physical properties of these superparamagnetic-fluorescent nanoparticles. These CdTe decorated magnetite nanoparticles were then functionalized with anti-epidermal growth factor receptor (EGFR) antibody to specifically target cells expressing this receptor. The EGFR is a transmembrane glycoprotein and is expressed on tumor cells from different tissue origins including human leukemic cell line Molt-4 cells. The magnetite-CdTe composite nanosystem is shown to perform excellently for specific selection, magnetic separation and fluorescent detection of EGFR positive Molt-4 cells from a mixed population. Flow cytometry and confocal laser scanning microscopy results show that this composite nanosystem has great potential in antibody functionalized magnetic separation and imaging of cells using cell surface receptor antibody.

Kale, Anup; Kale, Sonia; Yadav, Prasad; Gholap, Haribhau; Pasricha, Renu; Jog, J. P.; Lefez, Benoit; Hannoyer, Béatrice; Shastry, Padma; Ogale, Satishchandra

2011-06-01

158

Chiral magnetic microspheres purified by centrifugal field flow fractionation and microspheres magnetic chiral chromatography for benzoin racemate separation  

PubMed Central

Separation of enantiomers still remains a challenge due to their identical physical and chemical properties in a chiral environment, and the research on specific chiral selector along with separation techniques continues to be conducted to resolve individual enantiomers. In our laboratory the promising magnetic chiral microspheres Fe3O4@SiO2@cellulose-2, 3-bis (3, 5-dimethylphenylcarbamate) have been developed to facilitate the resolution using both its magnetic property and chiral recognition ability. In our present studies this magnetic chiral selector was first purified by centrifuge field flow fractionation, and then used to separate benzoin racemate by a chromatographic method. Uniform-sized and masking-impurity-removed magnetic chiral selector was first obtained by field flow fractionation with ethanol through a spiral column mounted on the type-J planetary centrifuge, and using the purified magnetic chiral selector, the final chromatographic separation of benzoin racemate was successfully performed by eluting with ethanol through a coiled tube (wound around the cylindrical magnet to retain the magnetic chiral selector as a stationary phase) submerged in dry ice. In addition, an external magnetic field facilitates the recycling of the magnetic chiral selector. PMID:23891368

Tian, Ailin; Qi, Jing; Liu, Yating; Wang, Fengkang; Ito, Yoichiro; Wei, Yun

2013-01-01

159

Magnetic properties and loss separation in iron-silicone-MnZn ferrite soft magnetic composites  

SciTech Connect

This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.0078

Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zou, Chao; Yang, Jun; Dong, Juan [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing (China)

2013-12-16

160

Highly sensitive and rapid detection of Pseudomonas aeruginosa based on magnetic enrichment and magnetic separation.  

PubMed

A method for highly sensitive and rapid detection of Pseudomonas aeruginosa, based on magnetic enrichment and magnetic separation, is described in this paper. The magnetic nanoparticles (MNPs) were applied to adsorb genome DNA after the sample was lysed. The DNA binding MNPs were directly subjected to polymerase chain reaction (PCR) to amplify gyrB specific sequence of Pseudomonas aeruginosa. The biotin labeled PCR products were detected by chemiluminescence when they were successively incubated with the probes-modified MNPs and alkaline phosphatase (ALP) labeled streptavidin (SA). Agarose gel electrophoresis analyses approved the method of in situ PCR to be highly reliable. The factors which could affect the chemiluminiscence were studied in detail. The results showed that the MNPs of 400 nm in diameter are beneficial to the detection. The sequence length and the binding site of the probe with a target sequence have obvious effects on the detection. The optimal concentration of the probes, hybridization temperature and hybridization time were 10 ?M, 60 ºC and 60 mins, respectively. The method of in situ PCR based on MNPs can greatly improve the utilization rate of the DNA template ultimately enhancing the detection sensitivity. Experiment results proved that the primer and probe had high specificity, and Pseudomonas aeruginosa was successfully detected with detection limits as low as 10 cfu/mL by this method, while the detection of a single Pseudomonas aeruginosa can also be achieved. PMID:23424183

Tang, Yongjun; Zou, Jun; Ma, Chao; Ali, Zeeshan; Li, Zhiyang; Li, Xiaolong; Ma, Ninging; Mou, Xianbo; Deng, Yan; Zhang, Liming; Li, Kai; Lu, Guangming; Yang, Haowen; He, Nongyue

2013-01-01

161

Magnetically separable nanoferrite-anchored glutathione: Aqueous homocoupling of arylboronic acids under microwave irradiation  

EPA Science Inventory

A highly active, stable and magnetically separable glutathione based organocatalyst provided good to excellent yields to symmetric biaryls in the homocoupling of arylboronic acids under microwave irradiation. Symmetrical biaryl motifs are present in a wide range of natural p...

162

High-Gradient Tests of the Single-Cell SC Cavity with a Feedback Waveguide  

NASA Astrophysics Data System (ADS)

Use of a superconducting (SC) traveling-wave accelerating (STWA) structure with a small phase advance per cell, rather than a standing-wave structure, may provide a significant increase in the accelerating gradient in the ILC linac [1]. For the same surface electric and magnetic fields, the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing-wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.

Yakovlev, V.; Solyak, N.; Wu, G.; Ge, M.; Gonin, I.; Khabiboulline, T.; Ozelis, J.; Rowe, A.; Avrakhov, P.; Kanareykin, A.; Rathke, J.

2010-11-01

163

An update on the study of high-gradient elliptical SRF cavities at 805 MHz for proton and other applications  

SciTech Connect

An update on the study of 805 MHz elliptical SRF cavities that have been optimized for high gradient will be presented. An optimized cell shape, which is still appropriate for easy high pressure water rinsing, has been designed with the ratios of peak magnetic and electric fields to accelerating gradient being 3.75 mT/(MV/m) and 1.82, respectively. A total of 3 single-cell cavities have been fabricated. Two of the 3 cavities have been tested so far. The second cavity achieved an E{sub acc} of {approx}50 MV/m at Q{sub 0} of 1.4 x 10{sup 10}. This result demonstrates that 805 MHz cavities can, in principle, achieve as high as, or could even be better than, 1.3 GHz high-gradient cavities.

Tajima, Tsuyoshi [Los Alamos National Laboratory; Haynes, Brian [Los Alamos National Laboratory; Krawczyk, Frank [Los Alamos National Laboratory; Madrid, Mike [Los Alamos National Laboratory; Roybal, Ray [Los Alamos National Laboratory; Simakov, Evgenya [Los Alamos National Laboratory; Clemens, Bob [TJNAF; Macha, Jurt [TJNAF; Manus, Bob [TJNAF; Rimmer, Bob [TJNAF; Rimmer, Bob [TJNAF; Turlington, Larry [TJNAF

2010-09-09

164

On-chip separation of magnetic particles with different magnetophoretic mobilities  

Microsoft Academic Search

Recent integrations of giant magnetoresistive sensor into laboratory-on-a-chip systems enable the direct detection of biological entities such as cells coated with magnetic particles on chip. However, before detection the different biological entities need to be separated. As a model system, we investigated the separation of two types of magnetic particles (4.5 and 2 mum in diameter). The motion of the

Chengxun Liu; Liesbet Lagae; Roel Wirix-Speetjens; Gustaaf Borghs

2007-01-01

165

Calculation of nanoparticle capture efficiency in magnetic drug targeting  

Microsoft Academic Search

The implant assisted magnetic targeted drug delivery system of Avilés, Ebner and Ritter, which uses high gradient magnetic separation (HGMS) is considered. In this 2D model large ferromagnetic particles are implanted as seeds to aid collection of multiple domain nanoparticles (radius ?200nm). Here, in contrast, single domain magnetic nanoparticles (radius in 20–100nm) are considered and the Langevin function is used

P. J. Cregg; Kieran Murphy; Adil Mardinoglu

2008-01-01

166

Separation of Earth's magnetic field internal component from observed data by means of Empirical Mode Decomposition  

NASA Astrophysics Data System (ADS)

The need to separate the magnetic field recorded at the Earth's surface into as many components as the sources are, has led to develop different methods of internal/external magnetic field separation. For this purpose, we have recently tested Empirical Mode Decomposition (EMD) over magnetic data registered by a few European observatories. Here we show an extension of the previous work using EMD to separate the internal component from data observed at a larger number of magnetic observatories from low to high latitudes. With respect to the methods used so far to achieve internal/external separation of Earth's magnetic field, EMD has many advantages as, for instance, to give the opportunity to be applied on data from a single observatory or also to be suitable to be implemented for real time internal/external separation. So, EMD has been applied to monthly means of X, Y and Z components of the geomagnetic field measured at the selected observatories and, after the evaluation of the properties of the EMD single monocomponents, the separation of the Earth's magnetic field internal contribution has been achieved. The internal component derived in this way has then been compared with the internal field provided not only by CM4 model, as in the previous test, but also with that provided by CHAOS4 model and by the more recently developed COV-OBS model. Encouraging results have been obtained.

Tozzi, Roberta; De Michelis, Paola; Consolini, Giuseppe

2014-05-01

167

On-chip magnetic separation of superparamagnetic beads for integrated molecular analysis  

PubMed Central

We have demonstrated a postprocessed complementary metal oxide semiconductor (CMOS) integrated circuit (IC) capable of on-chip magnetic separation, i.e., removing via magnetic forces the nonspecifically bound magnetic beads from the detection area on the surface of the chip. Initially, 4.5 ?m wide superparamagnetic beads sedimenting out of solution due to gravity were attracted to the detection area by a magnetic concentration force generated by flowing current through a conductor embedded in the IC. After sedimentation, the magnetic beads that did not bind strongly to the functionalized surface of the IC through a specific biochemical complex were removed by a magnetic separation force generated by flowing current through another conductor placed laterally to the detection area. As the spherical bead pivoted on the surface of the chip, the lateral magnetic force was further amplified by mechanical leveraging, and 50 mA of current flowing through the separation conductor placed 18 ?m away from the bead resulted in 7.5 pN of tensile force on the biomolecular tether immobilizing the bead. This force proved high enough to break nonspecific interactions while leaving specific antibody-antigen bonds intact. A sandwich capture immunoassay on purified human immunoglobulin G showed strong correlation with a control enzyme linked immunosorbent assay and a detection limit of 10 ng?ml or 70 pM. The beads bound to the detection area after on-chip magnetic separation were detected optically. To implement a fully integrated molecular diagnostics platform, the on-chip magnetic separation functionality presented in this work can be readily combine with state-of-the art CMOS-based magnetic bead detection technology. PMID:20368988

Florescu, Octavian; Wang, Kevan; Au, Patrick; Tang, Jimmy; Harris, Eva; Beatty, P. Robert; Boser, Bernhard E.

2010-01-01

168

A Novel Blind Separation Method in Magnetic Resonance Images  

PubMed Central

A novel global search algorithm based method is proposed to separate MR images blindly in this paper. The key point of the method is the formulation of the new matrix which forms a generalized permutation of the original mixing matrix. Since the lowest entropy is closely associated with the smooth degree of source images, blind image separation can be formulated to an entropy minimization problem by using the property that most of neighbor pixels are smooth. A new dataset can be obtained by multiplying the mixed matrix by the inverse of the new matrix. Thus, the search technique is used to searching for the lowest entropy values of the new data. Accordingly, the separation weight vector associated with the lowest entropy values can be obtained. Compared with the conventional independent component analysis (ICA), the original signals in the proposed algorithm are not required to be independent. Simulation results on MR images are employed to further show the advantages of the proposed method. PMID:24707318

Gao, Jianbin; Xia, Qi; Yin, Lixue; Zhou, Ji; Du, Li

2014-01-01

169

Aligning effect of magnetic field on PDLC films during the phase separation  

NASA Astrophysics Data System (ADS)

The results ofthe study ofthe uniaxially oriented PDLC films prepared by solvent induced phase separation (SIPS) method are presented. The samples were obtained applying a longitudinal magnetic field while the phase separation of the liquid crystal and polymer occurs due to the evaporation of common solvent from the uniform solution. In the presence of magnetic field the nematic liquid crystals 4-n-pentyl-4' -cyanophenylcyclohexane (5PCH), the 4-n-pentyl-4'- cyanobiphenyl (SCB) and nematic mixture LN-394 form the separate droplets in polyvinylbutyral (PVB) matrix. At that, the nematics 5PCH and LN-394 form always the stable bipolar structures with the order parameter of the droplet axes depending on the value of the applied field. In 5CB droplets the bipolar structure is realized only in a weak magnetic field and the radial one is formed in a strong magnetic field. At intermediate field the non-equilibrium structures are appeared that are characterized by the flickering textures.

Nazarov, V. G.; Parshin, A. M.; Zyryanov, V. Y.; Shabanov, V. F.; Lapanik, V. I.; Bezborodov, V. S.

2007-05-01

170

SECONDARY ELECTRON TRAJECTORIES IN HIGH-GRADIENT VACUUM INSULATORS WITH FAST HIGH-VOLTAGE PULSES  

SciTech Connect

Vacuum insulators composed of alternating layers of metal and dielectric, known as high-gradient insulators (HGIs), have been shown to withstand higher electric fields than conventional insulators. Primary or secondary electrons (emitted from the insulator surface) can be deflected by magnetic fields from external sources, the high-current electron beam, the conduction current in the transmission line, or the displacement current in the insulator. These electrons are deflected either toward or away from the insulator surface and this affects the performance of the vacuum insulator. This paper shows the effects of displacement current from short voltage pulses on the performance of high gradient insulators. Generally, vacuum insulator failure is due to surface flashover, initiated by electrons emitted from a triple junction. These electrons strike the insulator surface thus producing secondary electrons, and can lead to a subsequent electron cascade along the surface. The displacement current in the insulator can deflect electrons either toward or away from the insulator surface, and affects the performance of the vacuum insulator when the insulator is subjected to a fast high-voltage pulse. Vacuum insulators composed of alternating layers of metal and dielectric, known as high-gradient insulators (HGIs), have been shown to withstand higher electric fields than conventional insulators. HGIs, being tolerant of the direct view of high-current electron and ion beams, and having desirable RF properties for accelerators, are a key enabling technology for the dielectric-wall accelerators (DWA) being developed at Lawrence Livermore National Laboratory (LLNL). Characteristically, insulator surface breakdown thresholds go up as the applied voltage pulse width decreases. To attain the highest accelerating gradient in the DWA, short accelerating voltage pulses are only applied locally, along the HGI accelerator tube, in sync with the charged particle bunch, and the effects of displacement current on trajectories of electrons emitted from HGI surface are particularly interesting. This paper presents simulated electron trajectories experiencing either constant or short-duration applied voltage pulses. Comparisons of these trajectories clearly indicate the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process for HGIs.

Chen, Y; Blackfield, D; Nelson, S D; Poole, B

2010-04-21

171

Interaction of Separated Ferromagnetic Domains in a Hole-Doped Manganite Achieved by a Magnetic Field  

NASA Astrophysics Data System (ADS)

We report the change in the magnetic microstructure with the application of a magnetic field to a hole-doped manganite La0.81Sr0.19MnO3 in the mixed-phase state, in which ferromagnetic and paramagnetic phases coexist. In situ observations by electron holography have revealed that the applied magnetic field generates a “channel” of the magnetic flux in the paramagnetic phase region, thereby connecting the separated ferromagnetic domains. The magnetic flux density of this channel is estimated at 0.33T, which is comparable with that of the ferromagnetic domains. The connection of the separated ferromagnetic domains appears to promote the conduction in the mixed-phase state as predicted for many manganites exhibiting the magnetoresistance effect.

Yoo, J. H.; Murakami, Y.; Shindo, D.; Atou, T.; Kikuchi, M.

2004-07-01

172

Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides.  

PubMed

The magnetic excitations in the cuprate superconductors might be essential for an understanding of high-temperature superconductivity. In these cuprate superconductors the magnetic excitation spectrum resembles an hour-glass and certain resonant magnetic excitations within are believed to be connected to the pairing mechanism, which is corroborated by the observation of a universal linear scaling of superconducting gap and magnetic resonance energy. So far, charge stripes are widely believed to be involved in the physics of hour-glass spectra. Here we study an isostructural cobaltate that also exhibits an hour-glass magnetic spectrum. Instead of the expected charge stripe order we observe nano phase separation and unravel a microscopically split origin of hour-glass spectra on the nano scale pointing to a connection between the magnetic resonance peak and the spin gap originating in islands of the antiferromagnetic parent insulator. Our findings open new ways to theories of magnetic excitations and superconductivity in cuprate superconductors. PMID:25534540

Drees, Y; Li, Z W; Ricci, A; Rotter, M; Schmidt, W; Lamago, D; Sobolev, O; Rütt, U; Gutowski, O; Sprung, M; Piovano, A; Castellan, J P; Komarek, A C

2014-01-01

173

Hour-glass magnetic excitations induced by nanoscopic phase separation in cobalt oxides  

NASA Astrophysics Data System (ADS)

The magnetic excitations in the cuprate superconductors might be essential for an understanding of high-temperature superconductivity. In these cuprate superconductors the magnetic excitation spectrum resembles an hour-glass and certain resonant magnetic excitations within are believed to be connected to the pairing mechanism, which is corroborated by the observation of a universal linear scaling of superconducting gap and magnetic resonance energy. So far, charge stripes are widely believed to be involved in the physics of hour-glass spectra. Here we study an isostructural cobaltate that also exhibits an hour-glass magnetic spectrum. Instead of the expected charge stripe order we observe nano phase separation and unravel a microscopically split origin of hour-glass spectra on the nano scale pointing to a connection between the magnetic resonance peak and the spin gap originating in islands of the antiferromagnetic parent insulator. Our findings open new ways to theories of magnetic excitations and superconductivity in cuprate superconductors.

Drees, Y.; Li, Z. W.; Ricci, A.; Rotter, M.; Schmidt, W.; Lamago, D.; Sobolev, O.; Rütt, U.; Gutowski, O.; Sprung, M.; Piovano, A.; Castellan, J. P.; Komarek, A. C.

2014-12-01

174

Removal of freshwater microalgae by a magnetic separation method  

NASA Astrophysics Data System (ADS)

Some species of microalgae, with high growth rate and high lipid content, appear to be attractive alternatives as a feedstock for biodiesel production. The high-energy input for harvesting biomass and removing the water from the algae makes current commercial microalgal biodiesel production cost expensive. The major techniques currently employed in microalgae harvesting and recovery include centrifugation, coagulation-flocculation, bio-flocculation, filtration and screening, gravity sedimentation, and flotation. The purpose of this study was to investigate the harvesting of microalgae cells by coagulation using magnetic activated carbon, magnetite (FeO4) nanoparticles, and common chemical coagulants. Scenedesmus rubescens was selected and cultivated in 10 L flasks under continuous artificial light. Samples were taken at different operation intervals. Jar tests were conducted to investigate the effect of adsorption of microalgae on the magnetic material. The removal efficiency of microalgae was affected by the coagulants dose, stirring time and speed, and the initial microalgae concentration. The recovery of microalgae was greater in cultures with high initial microalgae concentration compared to cultures with low microalgae concentrations.

Vergini, Sofia S.; Aravantinou, Andriana F.; Manariotis, Ioannis D.

2013-04-01

175

Hollow mesoporous carbon spheres with magnetic cores and their performance as separable bilirubin adsorbents.  

PubMed

Hollow mesoporous carbon spheres with magnetic cores are directly replicated from hollow mesoporous aluminosilicate spheres with hematite cores by a simple incipient-wetness impregnation technique. The amount of magnetic cores and the saturation magnetization value can be easily tuned by changing the concentration of iron nitrate solution used in the synthesis procedure. As-prepared hollow mesoporous carbon spheres with magnetic cores are used as separable bilirubin adsorbents and show very good adsorptive properties. The characteristics of as-prepared composites are examined by XRD, N(2) sorption, TEM, vibrating-sample magnetometry, and UV/Vis spectroscopy. PMID:19582733

Guo, Limin; Cui, Xiangzhi; Li, Yongsheng; He, Qianjun; Zhang, Lingxia; Bu, Wenbo; Shi, Jianlin

2009-09-01

176

Ferronickel enrichment by fine particle reduction and magnetic separation from nickel laterite ore  

NASA Astrophysics Data System (ADS)

Ferronickel enrichment and extraction from nickel laterite ore were studied through reduction and magnetic separation. Reduction experiments were performed using hydrogen and carbon monoxide as reductants at different temperatures (700-1000°C). Magnetic separation of the reduced products was conducted using a SLon-100 cycle pulsating magnetic separator (1.2 T). Composition analysis indicates that the nickel laterite ore contains a total iron content of 22.50wt% and a total nickel content of 1.91wt%. Its mineral composition mainly consists of serpentine, hortonolite, and goethite. During the reduction process, the grade of nickel and iron in the products increases with increasing reduction temperature. Although a higher temperature is more favorable for reduction, the temperature exceeding 1000°C results in sintering of the products, preventing magnetic separation. After magnetic separation, the maximum total nickel and iron concentrations are 5.43wt% and 56.86wt%, and the corresponding recovery rates are 84.38% and 53.76%, respectively.

Tang, Xiao-hui; Liu, Run-zao; Yao, Li; Ji, Zhi-jun; Zhang, Yan-ting; Li, Shi-qi

2014-10-01

177

Optimisation of magnetic separation: a case study for soil washing at a heavy metals polluted site.  

PubMed

Sandy loam soil polluted with heavy metals (As, Cu, Pb and Zn) from an ancient Mediterranean Pb mining and metallurgy site was treated by means of wet high-intensity magnetic separation to remove some of the pollutants therein. The treated fractions were chemically analysed and then subjected to magnetic characterisation, which determined the high-field specific (mass), magnetic susceptibility (?) and the specific (mass) saturation magnetisation (?S), through isothermal remanent magnetisation (IRM) curves. From the specific values of ? and ?S, a new expression to assess the performance of the magnetic separation operation was formulated and verified by comparison with the results obtained by traditional chemical analysis. The magnetic study provided valuable information for the exhaustive explanation of the operation, and the deduced mathematical expression was found to be appropriate to estimate the performance of the separation operation. From these results we determined that magnetic soil washing was effective for the treatment of the contaminated soil, concentrating the majority of the heavy metals and peaking its separation capacity at 60% of the maximum output voltage. PMID:24418067

Sierra, C; Martínez-Blanco, D; Blanco, Jesús A; Gallego, J R

2014-07-01

178

EFFICIENCY ENHANCEMENTS THROUGH THE USE OF MAGNETIC FIELD GRADIENT IN ORIENTATION MAGNETIC SEPARATION FOR THE REMOVAL OF POLLUTANTS BY MAGNETOTACTIC BACTERIA  

Microsoft Academic Search

Orientation magnetic separation (OMS) represents a simple method that permits motile, field-susceptible magnetotactic bacteria (MTB) to be separated from water. Such an approach can be used to decontaminate polluted water through uptake of contaminants by the bacteria and their subsequent removal by the application of magnetic fields. In OMS, a separation channel through which an MTB culture is flowing is

A. S. Bahaj; P. A. B. James; F. D. Moeschler

2002-01-01

179

Theory of factors limiting high gradient operation of warm accelerating structures  

SciTech Connect

This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded accelerating (DLA) structures where the main problem is the occurrence of multipactor on dielectric surfaces, and (b) studies of effects associated with either RF magnetic or RF electric fields which may cause the RF breakdown in high-gradient metallic accelerating structures. In the studies of DLA structures, at least, two accomplishments should be mentioned: the development of a 3D non-stationary, self-consistent code describing the multipactor phenomena and yielding very good agreement with some experimental data obtained in joint ANL/NRL experiments. In the metallic structures, such phenomena as the heating and melting of micro-particles (metallic dust) by RF electric and magnetic fields in single-shot and rep-rate regimes is analyzed. Also, such processes in micro-protrusions on the structure surfaces as heating and melting due to the field emitted current and the Nottingham effect are thoroughly investigated with the account for space charge of emitted current on the field emission from the tip.

Nusinovich, Gregory S. [University of Maryland; Antonsen, Thomas M. [University of Maryland; Kishek, Rami [University of Maryland

2014-07-25

180

Magnetophoresis 'meets' viscoelasticity: deterministic separation of magnetic particles in a modular microfluidic device.  

PubMed

The deflection of magnetic beads in a microfluidic channel through magnetophoresis can be improved if the particles are somehow focused along the same streamline in the device. We design and fabricate a microfluidic device made of two modules, each one performing a unit operation. A suspension of magnetic beads in a viscoelastic medium is fed to the first module, which is a straight rectangular-shaped channel. Here, the magnetic particles are focused by exploiting fluid viscoelasticity. Such a channel is one inlet of the second module, which is a H-shaped channel, where a buffer stream is injected in the second inlet. A permanent magnet is used to displace the magnetic beads from the original to the buffer stream. Experiments with a Newtonian suspending fluid, where no focusing occurs, are carried out for comparison. When viscoelastic focusing and magnetophoresis are combined, magnetic particles can be deterministically separated from the original streamflow to the buffer, thus leading to a high deflection efficiency (up to ~96%) in a wide range of flow rates. The effect of the focusing length on the deflection of particles is also investigated. Finally, the proposed modular device is tested to separate magnetic and non-magnetic beads. PMID:25732596

Del Giudice, Francesco; Madadi, Hojjat; Villone, Massimiliano M; D'Avino, Gaetano; Cusano, Angela M; Vecchione, Raffaele; Ventre, Maurizio; Maffettone, Pier Luca; Netti, Paolo A

2015-03-31

181

Closed-loop magnetic separation of nanoparticles on a packed bed of spheres  

NASA Astrophysics Data System (ADS)

In this work, we consider magnetic separation of iron oxide nanoparticles when a nanoparticle suspension (diluted ferrofluid) passes through a closed-loop filter composed of a packed bed of micro-beads magnetized by an externally applied magnetic field. We show that the capture of nanoparticles of a size as small as 60 nm is easily achieved at low-to-moderate magnetic fields (16-32 kA/m) thanks to relatively strong magnetic interactions between them. The key parameter governing the capture process is the Mason number—the ratio of hydrodynamic-to-magnetic forces exerted to nanoparticles. The filter efficiency, ?, defined through the ratio of the inlet-to-outlet concentration shows a power-law dependency on Mason number, ??M a-0.83 , in the range of 102magnetic nanoparticles, followed by magnetic separation of the nanoparticles.

Magnet, Cécilia; Akouala, Mesferdon; Kuzhir, Pavel; Bossis, Georges; Zubarev, Andrey; Wereley, Norman M.

2015-05-01

182

Flow enhanced non-linear magnetophoretic separation of beads based on magnetic susceptibility.  

PubMed

Magnetic separation provides a rapid and efficient means of isolating biomaterials from complex mixtures based on their adsorption on superparamagnetic (SPM) beads. Flow enhanced non-linear magnetophoresis (FNLM) is a high-resolution mode of separation in which hydrodynamic and magnetic fields are controlled with micron resolution to isolate SPM beads with specific physical properties. In this article we demonstrate that a change in the critical frequency of FNLM can be used to identify beads with magnetic susceptibilities between 0.01 and 1.0 with a sensitivity of 0.01 Hz(-1). We derived an analytical expression for the critical frequency that explicitly incorporates the magnetic and non-magnetic composition of a complex to be separated. This expression was then applied to two cases involving the detection and separation of biological targets. This study defines the operating principles of FNLM and highlights the potential for using this technique for multiplexing diagnostic assays and isolating rare cell types. PMID:24061548

Li, Peng; Kilinc, Devrim; Ran, Ying-Fen; Lee, Gil U

2013-11-21

183

Thermal diffusion of magnetic nanoparticles in ferrocolloids: Experiments on particle separation in vertical columns  

Microsoft Academic Search

Experiments on nonstationary separation of nanometer-sized Fe3O4 particles of hydrocarbon-based ferrocolloids in a flat vertical thermal diffusion column are performed. By using a modified separation theory which accounts for an one-dimensional mixed (thermal and concentration) convection in the column, the Soret coefficient of magnetic nanoparticles are calculated. It is shown that particles are transferred in the direction of decreasing temperature.

Elmars Blums; Ansis Mezulis; Michail Maiorov; Gunars Kronkalns

1997-01-01

184

Conceptual design of integrated microfluidic system for magnetic cell separation, electroporation, and transfection.  

PubMed

For the purposes of a successful ex vivo gene therapy we have proposed and analyzed a new concept of an integrated microfluidic system for combined magnetic cell separation, electroporation, and magnetofection. For the analysis of magnetic and electric field distribution (given by Maxwell equations) as well as dynamics of magnetically labeled cell and transfection complex, we have used finite element method directly interfaced to the Matlab routine solving Newton dynamical equations of motion. Microfluidic chamber has been modeled as a channel with height and length 1 mm and 1 cm, respectively. Bottom electrode consisted of 100 parallel ferromagnetic straps and the upper electrode was plate of diamagnetic copper. From the dynamics of magnetic particle motion we have found that the characteristic time-scales for the motion of cells (mean capture time ? 4 s) and gene complexes (mean capture time ? 3 min), when permanent magnets are used, are in the range suitable for efficient cell separation and gene delivery. The largest electric field intensity (?10 kV/m) was observed at the edges of the microelectrodes, in the close proximity of magnetically separated cells, which is optimal for subsequent cell electroporation. PMID:23260767

Durdík, Š; Kraf?ík, A; Babincová, M; Babinec, P

2013-09-01

185

A new magnetic bead-based, filterless bio-separator with planar electromagnet surfaces for integrated bio-detection systems  

Microsoft Academic Search

A new filterless bio-separator separating magnetic microbeads from a carrier fluid has been designed, fabricated, and characterized as a core component of biological cell sampling and detecting systems. To maximize the sampling capability, a planar electromagnet surface with a serpentine coil and semi-encapsulated permalloy has been realized. Using this bio-separator, antibody-coated magnetic beads have been successfully separated from the bio-buffer

Jin-Woo Choi; Chong H Ahn; Shekhar Bhansali; H. Thurman Henderson

2000-01-01

186

New High Performance Magnet Structures for Bead Based MolecularSeparation  

SciTech Connect

New High Performance Magnet Structures for Bead Based Molecular Separation David Humphries Lawrence Berkeley National Laboratory, D.O.E. Joint Genome Institute Abstract High performance Hybrid magnetic separation technology is under continuing development at the D.O.E. Joint Genome Institute and Lawrence Berkeley National Laboratory for general laboratory and high throughput automated applications. This technology has broad applicability for molecular separation in genomics, proteomics and other areas. It s applicability ranges from large and small scale microtiter plate and flow separation processes to single molecule DNA manipulation. It is currently an enabling purification technology for very high throughput production sequencing at the D.O.E. Joint Genome Institute. This technology incorporates hybrid magnetic structures that combine linear permanent magnet material and ferromagnetic material to produce significantly higher fields and gradients than those of currently available commercial devices. These structures incorporate ferromagnetic poles that can be easily shaped to produce complex field distributions for specialized applications. The higher maximum fields and strong gradients of the hybrid structures result in greater holding forces on magnetized targets that are being processed as well as faster extraction. Current development versions of these magnet plates have exhibited fields in excess of 1.0 tesla and gradients approaching 1000.0 tesla/meter. Second generation Hybrid magnet plates have now been developed for both 384 and 96-well applications. This technology is currently being made available to industry through the Tech Transfer Department at Lawrence Berkeley National Laboratory. This work was performed under the auspices of the US Department of Energy's Office of Science, Biological and Environmental Research Program and the by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48, Lawrence Berkeley National Laboratory under contract No. DE-AC03-6SF00098 and Los Alamos National Laboratory under contract No. W-7405-ENG-36.

Humphries, David

2005-06-01

187

Design of large aperture superferric quadrupole magnets for an in-flight fragment separator  

NASA Astrophysics Data System (ADS)

Superferric quadrupole magnets to be used for in-flight fragment separator have been designed. A quadrupole magnet triplet for beam focusing is placed in a cryostat together with superconducting correction coils. To maximize acceptance of rare isotope beams produced by projectile fragmentation, it is essential to use large-aperture quadrupole magnets. The pole tip radius is 17 cm in the current design, and we tried to enlarge the aperture with 3D analysis on magnetic fields. In the front end of the separator, where a target and beam dump are located, we plan to use two sets of quadrupole triplets made of high-Tc superconductor (HTS) operating at 20-50 K considering high radiation heat load. The HTS magnet will use warm iron poles. Both low-Tc and high-Tc superconductors are acquired for test winding, and two kinds of dewar and cryostat are under construction to perform the coil and magnet tests. The magnetic design of superferric quadrupole is mainly discussed.

Zaghloul, Aziz; Kim, Dogyun; Kim, Jangyoul; Kim, Mijung; Kim, Myeongjin; Yun, Chongcheoul; Kim, Jongwon

2014-01-01

188

Investigation for Magnetic Separation of Oxygen from Supercritical Air Near the Maxcondentherm Point  

NASA Astrophysics Data System (ADS)

In an effort to develop a highly effective separation technology for oxygen operating in the liquefied natural gas (LNG) temperature range, the magnetic separation of oxygen from supercritical air was investigated using a laser holography interferometer. The experiment was carried out near the maxcondentherm (MC) point. For purposes of comparison, the same operation was carried out using supercritical nitrogen. Here, a neodymium magnet was used and the magnetic force was conducted into the experimental cell through a magnetic alloy rod. Density variation caused by the magnetic force was observed in this study. In the case of supercritical air, the density gradient was formed around the tip of the rod, whereas in the case of supercritical nitrogen, no density gradient was observed. This fact strongly suggested that oxygen was attracted by the magnetic force and highly condensed on the surface at the tip of the rod, leading us to suppose that it might be exploited in a new purification system of gaseous oxygen using magnetic force.

Nakano, A.; Shiraishi, M.

2004-06-01

189

Design of large aperture superferric quadrupole magnets for an in-flight fragment separator  

SciTech Connect

Superferric quadrupole magnets to be used for in-flight fragment separator have been designed. A quadrupole magnet triplet for beam focusing is placed in a cryostat together with superconducting correction coils. To maximize acceptance of rare isotope beams produced by projectile fragmentation, it is essential to use large-aperture quadrupole magnets. The pole tip radius is 17 cm in the current design, and we tried to enlarge the aperture with 3D analysis on magnetic fields. In the front end of the separator, where a target and beam dump are located, we plan to use two sets of quadrupole triplets made of high-Tc superconductor (HTS) operating at 20-50 K considering high radiation heat load. The HTS magnet will use warm iron poles. Both low-Tc and high-Tc superconductors are acquired for test winding, and two kinds of dewar and cryostat are under construction to perform the coil and magnet tests. The magnetic design of superferric quadrupole is mainly discussed.

Zaghloul, Aziz; Kim, Dogyun; Kim, Jangyoul; Kim, Mijung; Kim, Myeongjin; Yun, Chongcheoul; Kim, Jongwon [Rare Isotope Science Project, Institute for Basic Science, Yuseong, Daejeon, 305-811 (Korea, Republic of)

2014-01-29

190

Magnetic field effect on laser isotope separation of gadolinium based on polarization selection rules  

Microsoft Academic Search

In the laser isotope separation based on the polarization selection rules, the dependence of magnetic field strength on the isotopic selectivity was experimentally measured by using atomic Gd vapor. The Lande factor for the high-lying exited level was newly determined.

S. Tokita; Y. Izawa; H. Niki

2003-01-01

191

Magnetic separation of colloidal nanoparticle mixtures using a material specific peptide.  

PubMed

A material specific peptide bound to Fe2O3 facilitates the selective sequestration of Au from a colloidal mixture of Au and CdS nanoparticles; the Au-Fe2O3 precipitate can then be magnetically separated from the colloidal CdS, and the Au nanoparticles can be recovered upon release from the Fe2O3. PMID:23661051

Essinger-Hileman, Elizabeth R; Popczun, Eric J; Schaak, Raymond E

2013-06-18

192

Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia  

SciTech Connect

A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to three conservation laws. Electron inertia leads to outward electron separation from the magnetic streamtubes. The progressive plasma filling of the adjacent vacuum region is consistent with electron-inertia being part of finite electron Larmor radius effects, which increase downstream and eventually demagnetize the plasma. Current ambipolarity is not fulfilled and ion separation can be either outwards or inwards of magnetic streamtubes, depending on their magnetization. Electron separation penalizes slightly the plume efficiency and is larger for plasma beams injected with large pressure gradients. An alternative nonzero electron-inertia model [E. Hooper, J. Propul. Power 9, 757 (1993)] based on cold plasmas and current ambipolarity, which predicts inwards electron separation, is discussed critically. A possible competition of the gyroviscous force with electron-inertia effects is commented briefly.

Ahedo, Eduardo; Merino, Mario [Universidad Politecnica de Madrid, 28040 Madrid (Spain)

2012-08-15

193

Superconducting open-gradient magnetic separation for the pretreatment of radioactive or mixed waste vitrification feeds. 1998 annual progress report  

SciTech Connect

'The objective is to reduce the volume and cost of high-level waste glass produced during US DOE remediation activities by demonstrating that magnetic separation can separate crystalline, amorphous, and colloidal constituents in vitrification feed streams known to be deleterious to the production of borosilicate glass. Magnetic separation will add neither chemicals nor generate secondary waste streams. The project includes the systematic study of magnetic interactions of waste constituents under controlled physical and chemical conditions (e.g., hydration, oxidation, temperature) to identify mechanisms that control the magnetic properties. Partitioning of radionuclides to determine their sorption mechanisms is also being studied. The identification of fundamental magnetic properties within the microscopic chemical environment in combination with hydrodynamic and electrodynamic models provides insights into the design of a system for optimal separation. Following this, experimental studies using superconducting open-gradient magnetic separation (OGMS) will be conducted to validate its effectiveness as a pretreatment technique.'

Doctor, R.D.; Nunez, L. [Argonne National Lab., IL (US); Crawford, C. [Westinghouse Savannah River Co., Aiken, SC (US); Ritter, J. [Univ. of South Carolina, Columbia, SC (US); Landsberger, S. [Univ. of Texas, Austin, TX (US)

1998-06-01

194

?-Detected NMR Search for Magnetic Phase Separation in Epitaxial GaAs:Mn  

NASA Astrophysics Data System (ADS)

To test for the microscopic magnetic phase separation in the dilute magnetic semiconductor Ga1-xMnxAs sug-gested by low energy muon spin rotation measurements[1], we present a detailed analysis of the amplitudes of the 8Li ?-detected nuclear magnetic resonance in an epitaxially grown thin film of x = 5.4% Mn doped GaAs on a semi-insulating GaAs substrate with magnetic transition temperature TC =72 K. The spectrum at 100 K corresponds to 73% of the full room temperature amplitude, and at 60 K to about 62%. The 11% loss of signal through the magnetic tran-sition is much smaller than that ? 50% found by low energy ?SR[1], and may be entirely due to an amplitude change intrinsic to GaAs. This lack of evidence for phase separation is, however, consistent with the full volume fraction magnetism found by a second low energy ?SR measurement on a different sample using weak transverse field[2].

Song, Q.; Chow, K. H.; Miller, R. I.; Fan, I.; Hossain, M. D.; Kiefl, R. F.; Morris, G. D.; Kreitzman, S. R.; Levy, C. D. P.; Parolin, T. J.; Pearson, M. R.; Salman, Z.; Saadaoui, H.; Smadella, M.; Wang, D.; Yu, K. M.; Liu, X.; Furdyna, J. K.; MacFarlane, W. A.

195

Latest Results of ILC High-Gradient R&D 9-cell Cavities at JLAB  

SciTech Connect

It has been over a year since JLAB started processing and testing ILC 9-cell cavities in the frame work of ILC high-gradient cavity R&D, aiming at the goal of a 35 MV/m gradient at a Q #4; of 1E10 with a yield of 90%. The necessary cavity processing steps include field flatness tuning, electropolishing (EP), hydrogen out-gassing under vacuum, high-pressure water rinsing, clean room assembly, and low temperature bake. These are followed by RF test at 2 Kelvin. Ultrasonic cleaning with Micro-90, an effective post-EP rinsing recipe discovered at JLAB, is routinely used. Seven industry manufactured 9-cell TESLAshape cavities are processed and tested repeatedly. So far, 33 EP cycles are accumulated, corresponding to more than 65 hours of active EP time. An emphasis put on RF testing is to discern cavity quench characteristics, including its nature and its location. Often times, the cavity performance is limited by thermal-magnetic quench instead of field emission. The quench field in some cavities is lower than 20 MV/m and remains unchanged despite repeated EP, implying material and/or fabrication defects. The quench field in some other cavities is high but changes unpredictably after repeated EP, suggesting processing induced defects. Based on our experience and results, several areas are identified where improvement is needed to improve cavity performance as well as yield.

Rongli Geng

2008-02-11

196

Magnetic materials as sorbents for metal/metalloid preconcentration and/or separation. A review.  

PubMed

The use of magnetic materials in solid phase extraction has received considerable attention in recent years taking into account many advantages arising from the inherent characteristics of magnetic particles. Magnetic solid phase extraction (MSPE) methodology overcomes problems such as column packing and phase separation, which can be easily performed by applying an external magnetic field. The use of magnetic particles in automatic systems is growing over the last few years making the on-line operation of MSPE a promising technique in the frame of green chemistry. This article aims to provide all recent progress in the research of novel magnetic materials as sorbents for metal preconcentration and determination coupled with different detection systems as well as their implementation in sequential injection and microfluidic systems. In addition, a description of preparation, characterization as well as applications of various types of magnetic materials, either with organic or inorganic coating of the magnetic core, is presented. Concluding remarks and future trends are also commented. PMID:23856225

Giakisikli, Georgia; Anthemidis, Aristidis N

2013-07-30

197

Separation Nanotechnology of Diethylenetriaminepentaacetic Acid Bonded Magnetic Nanoparticles for Spent Nuclear Fuel  

SciTech Connect

A nanomagnetic separation method based on Diethylenetriaminepentaacetic acid (DTPA) conjugated with magnetic nanoparticles (MNPs) is studied for application in spent nuclear fuel separation. The high affinity of DTPA towards actinides aids in separation from the highly acidic medium of nuclear waste. The solubility and magnetization of particles at low pH is protected by encapsulating them in silica layer. Surface functionalization of silica coated particles with polyamines enhances the loading capacity of the chelators on MNPs. The particles were characterized before and after surface modification using transmission electron microscopy (TEM), helium ion microscopy (HIM), Fourier transform-infrared (FT-IR) spectrometry, and X-ray diffractometry. The coated and uncoated samples were studied using vibrating sample magnetometer (VSM) to understand the change in magnetic properties due to the influence of the surface functionalization. The hydrodynamic size and surface charge of the particles are investigated using Dynamic Light Scattering (DLS). The uptake behavior of Am(III), Pu(IV), U(VI), and Np(V) from 0.1M NaNO3 solution was investigated. The sorption result shows the strong affinity of DTPA towards Am(III) and Pu(IV) by extracting 97% and 80% of actinides, respectively. The high removal efficiency and fast uptake of actinides make the chelator conjugated MNPs an effective method for spent nuclear fuel separation.

Kaur, Maninder [Idaho Univ., Moscow, ID (United States); Johnson, Andrew [Idaho Univ., Moscow, ID (United States); Tian, Guoxin [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Jiang, Weilin [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Rao, Linfeng [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Paszczynski, Andrzej [Idaho Univ., Moscow, ID (United States); Qiang, You [Center for Advanced Energy Studies, Idaho Falls, ID (United States); Idaho Univ., Moscow, ID (United States)

2013-01-15

198

Bulk magnetization and nuclear magnetic resonance of magnetically purified layered silicates and their polymer-based nanocomposites  

NASA Astrophysics Data System (ADS)

The bulk magnetization and the H1 and Si29 nuclear-magnetic-resonance (NMR) spectra of two layered silicates, montmorillonite (MMT) and hectorite (HCT), purified by high-gradient magnetic separation, and of HCT-polymer nanocomposites have been measured. At 300K, the magnetization of MMT as received shows a behavior typical of paramagnets and does not change significantly even after ˜100h of magnetic separation. The magnetization of HCT as received is typical of a weak ferromagnet but it changes drastically after magnetic separation. The extracted particles have sizes varying from a few to about 150?m and show ferromagneticlike properties at 300K. While the magnetization/magnetic-field ratio, M /H, of HCT is reduced 50-fold after ˜15min of magnetic separation and shows predominantly diamagnetic properties at 300K after ˜30h, we have also found that HCT contains ˜0.2mass% of paramagnetic Fe ions, with an effective magnetic moment of ˜5.2?B per Fe ion, as a regular element of its lattice. This is much smaller than the ˜3.8mass% in MMT. Spinning sidebands in H1 NMR spectra of HCT as received are reduced by magnetic separation. This indicates that dipolar interactions between nuclei and paramagnetic ions even in separated phases can affect the NMR spectra. Magnetically purified hectorite was used for preparing polymer-HCT nanocomposites where the NMR spectra show increased signal-to-noise ratios.

Levin, E. M.; Rawal, A.; Bud'ko, S. L.; Kracher, A.; Schmidt-Rohr, K.

2005-12-01

199

Haloing in bimodal magnetic colloids: the role of field-induced phase separation.  

PubMed

If a suspension of magnetic micrometer-sized and nanosized particles is subjected to a homogeneous magnetic field, the nanoparticles are attracted to the microparticles and form thick anisotropic halos (clouds) around them. Such clouds can hinder the approach of microparticles and result in effective repulsion between them [M. T. López-López, A. Yu. Zubarev, and G. Bossis, Soft Matter 6, 4346 (2010)]. In this paper, we present detailed experimental and theoretical studies of nanoparticle concentration profiles and of the equilibrium shapes of nanoparticle clouds around a single magnetized microsphere, taking into account interactions between nanoparticles. We show that at a strong enough magnetic field, the ensemble of nanoparticles experiences a gas-liquid phase transition such that a dense liquid phase is condensed around the magnetic poles of a microsphere while a dilute gas phase occupies the rest of the suspension volume. Nanoparticle accumulation around a microsphere is governed by two dimensionless parameters--the initial nanoparticle concentration (?(0)) and the magnetic-to-thermal energy ratio (?)--and the three accumulation regimes are mapped onto a ?-?(0) phase diagram. Our local thermodynamic equilibrium approach gives a semiquantitative agreement with the experiments on the equilibrium shapes of nanoparticle clouds. The results of this work could be useful for the development of the bimodal magnetorheological fluids and of the magnetic separation technologies used in bioanalysis and water purification systems. PMID:23005414

Magnet, C; Kuzhir, P; Bossis, G; Meunier, A; Suloeva, L; Zubarev, A

2012-07-01

200

Measurement of the magnetic interaction between two bound electrons of two separate ions  

NASA Astrophysics Data System (ADS)

Electrons have an intrinsic, indivisible, magnetic dipole aligned with their internal angular momentum (spin). The magnetic interaction between two electronic spins can therefore impose a change in their orientation. Similar dipolar magnetic interactions exist between other spin systems and have been studied experimentally. Examples include the interaction between an electron and its nucleus and the interaction between several multi-electron spin complexes. The challenge in observing such interactions for two electrons is twofold. First, at the atomic scale, where the coupling is relatively large, it is often dominated by the much larger Coulomb exchange counterpart. Second, on scales that are substantially larger than the atomic, the magnetic coupling is very weak and can be well below the ambient magnetic noise. Here we report the measurement of the magnetic interaction between the two ground-state spin-1/2 valence electrons of two 88Sr+ ions, co-trapped in an electric Paul trap. We varied the ion separation, d, between 2.18 and 2.76 micrometres and measured the electrons' weak, millihertz-scale, magnetic interaction as a function of distance, in the presence of magnetic noise that was six orders of magnitude larger than the magnetic fields the electrons apply on each other. The cooperative spin dynamics was kept coherent for 15 seconds, during which spin entanglement was generated, as verified by a negative measured value of -0.16 for the swap entanglement witness. The sensitivity necessary for this measurement was provided by restricting the spin evolution to a decoherence-free subspace that is immune to collective magnetic field noise. Our measurements show a d-3.0(4) distance dependence for the coupling, consistent with the inverse-cube law.

Kotler, Shlomi; Akerman, Nitzan; Navon, Nir; Glickman, Yinnon; Ozeri, Roee

2014-06-01

201

Preparation of thermosensitive polymer magnetic particles and their application in protein separations.  

PubMed

This paper presents a kind of thermoresponsive polymeric magnetic particles for protein separations. The magnetofluids were directly encapsulated in hollow particles constructed by self-assembly of rod-coil poly(ethylene glycol)-poly(N-isopropylacrylamide)/?-cyclodextrin (PEG-PNIPAM/?-CD) complexes. The resulting particles showed reversible protein absorption/desorption capacity because the reversible thermo-sensitivity of PNIPAM. Above the lower critical solution temperature (LCST) of PNIPAM, these particles showed high absorptive capacities and adsorption was done at lower temperature. The protein-laden particles are readily removed from the feed solution in a magnetic field. PMID:25222511

Luo, Ling; Zhang, Hong-Su; Liu, Yan; Ha, Wei; Li, Luo-Hao; Gong, Xiao-Lei; Li, Bang-Jing; Zhang, Sheng

2014-12-01

202

The role of magnetic fields on the membrane-based separation of aqueous electrolyte solutions  

NASA Astrophysics Data System (ADS)

Molecular simulations using the method of molecular dynamics have been carried out to examine the role that external magnetic fields can play in the transport of water via reverse osmosis (RO) across membranes. Our results show that magnetic fields can increase the transport rate of water across such membranes significantly. These observations can have an important impact on making RO separation processes that involve the removal of water from solutions more efficient, since low flux rates across membranes is an important problem encountered in most current RO processes. We are aware of no experimental studies of such effects.

Murad, S.

2006-01-01

203

Separation of electrostatic and magnetic phase shifts using a modified transport-of-intensity equation.  

PubMed

We introduce a new approach for the separation of the electrostatic and magnetic components of the electron wave phase shift, based on the transport-of-intensity equation (TIE) formalism. We derive two separate TIE-like equations, one for each of the phase shift components. We use experimental results on FeCoB and Permalloy patterned islands to illustrate how the magnetic and electrostatic longitudinal derivatives can be computed. The main advantage of this new approach is the fact that the differences in the power spectra of the two phase components (electrostatic phase shifts often have significant power in the higher frequencies) can be accommodated by the selection of two different Tikhonov regularization parameters for the two phase reconstructions. The extra computational demands of the method are more than compensated by the improved phase reconstruction results. PMID:24513573

Humphrey, E; Phatak, C; Petford-Long, A K; De Graef, M

2014-04-01

204

Fingerprints of intrinsic phase separation in magnetically-doped 2DEG  

NASA Astrophysics Data System (ADS)

We theoretically study the properties of a recently observed [1] inhomogeneous phase preceding the metal-insulator transition in a magnetically-doped two-dimensional electron gas (2DEG). We show that, due to competition between (ferromagnetic) double-exchange and (anti-ferromagnetic) super-exchange, at very low carrier density such a system is unstable toward intrinsic phase separation (PS). Here, ferromagnetic carrier-rich (metallic) ``droplets'' emerge within a magnetically disordered carrier-poor (insulating) matrix. Our calculations indicate that this regime should display very unusual transport, featuring colossal magneto-resistance with exceptionally weak density dependence - in striking agreement with experiments [1] on CdMnTe quantum wells. Such exotic transport properties - we argue - should be considered as ``fingerprints'' for intrinsic phase separation, a behavior very different from situations where phase coexistence is driven by disorder due to extrinsic impurities or defects. [1] J. Jaroszyñski et al., Phys. Rev. B 76, 045322 (2007).

Terletska, Hanna; Dobrosavljevic, Vladimir

2009-03-01

205

Fluorescent and superparamagnetic hybrid quantum clusters for magnetic separation and imaging of cancer cells from blood  

NASA Astrophysics Data System (ADS)

We demonstrate here the generation of fluorescent superparamagnetic quantum clusters through a greener aqueous route by fusing highly fluorescent gold clusters with superparamagnetic nanoparticles. We conjugated transferrin onto the hybrid clusters to get cell accessibility and assessed their hemocompatibility and cytotoxicity. The ability of the clusters to selectively remove cancer cell lines (C6 glioma cells) from fluids including blood and the fluorescent imaging of the separated cells is demonstrated. The pattering of the clusters in response to an external magnetic field is also shown. Efficient cancer cell separation, imaging and magnetic pattering can be realized by the highly hemocompatible and noncytotoxic hybrid clusters reported here. It seems the probe has potential for further exploration in multimodal imaging of circulating cancer cells.We demonstrate here the generation of fluorescent superparamagnetic quantum clusters through a greener aqueous route by fusing highly fluorescent gold clusters with superparamagnetic nanoparticles. We conjugated transferrin onto the hybrid clusters to get cell accessibility and assessed their hemocompatibility and cytotoxicity. The ability of the clusters to selectively remove cancer cell lines (C6 glioma cells) from fluids including blood and the fluorescent imaging of the separated cells is demonstrated. The pattering of the clusters in response to an external magnetic field is also shown. Efficient cancer cell separation, imaging and magnetic pattering can be realized by the highly hemocompatible and noncytotoxic hybrid clusters reported here. It seems the probe has potential for further exploration in multimodal imaging of circulating cancer cells. Electronic supplementary information (ESI) available: HRTEM, FTIR spectra, XRD of the samples and fluorescent microscope images are showed in supporting information in the order they discussed in the text. See DOI: 10.1039/c1nr10900f

Durgadas, C. V.; Sharma, Chandra P.; Sreenivasan, K.

2011-11-01

206

Design of a cellular-uptake-shielding magnetic catcher for cancer cell separation.  

PubMed

Fluorescent-magnetic-biotargeting multifunctional microcapsules (FMBMMs) are designed and fabricated via layer-by-layer assembly. It is found that the arginine-glycine-aspartate-modified FMBMMs were capable of sensitively detecting and efficiently isolating approximately 80% target cancer cells within 20 min. More importantly, FMBMMs present a general template for identifying and separating multiple types of cancer cells simply by altering the recognition motif. PMID:22965892

Wang, Ya; Zhang, Jing; Jia, Hui-Zhen; Yang, Juan; Qin, Si-Yong; Liu, Chen-Wei; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2012-10-01

207

Magnetic properties and loss separation in iron powder soft magnetic composite materials  

Microsoft Academic Search

New developments in powder metallurgical composites make soft magnetic composite (SMC) material interesting for application in electrical machines, when combined with new machine design rules and new production techniques. In order to establish these design rules, one must pay attention to electromagnetic loss characteristics of SMC material. In this work, five different series of iron based SMCs are produced and

Marc de Wulf; Ljubomir Anestiev; Luc Dupré; Ludo Froyen; Jan Melkebeek

2002-01-01

208

Analysis Code for High Gradient Dielectric Insulator Surface Breakdown  

SciTech Connect

High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices.

Ives, Robert Lawrence [Calabazas Creek Research, Inc.; Verboncoeur, John [University of California - Berkeley; Aldan, Manuel [University of California, Berkeley

2010-05-30

209

SLIM, Short-pulse Technology for High Gradient Induction Accelerators  

SciTech Connect

The conclusions of this paper are: (1) The gradient of the SLIM-based technology is believed to be achievable in the same range as it is for the gradient of a modern rf-linac technology ({approx}100 MeV per meter). (2) The SLIM concept is based on the nsec TEM pulse mode operation with no laser or rf systems. (3) Main components of SLIM are not stressed while the energy is pumped into the induction system. Components can accept the hard environment conditions such as a radiation dose, mismatch, hard electromagnetic nose level, etc. Only for several nanoseconds the switch is OFF and produces a stress in the induction system. At that time, the delivery of energy to the beam takes place. (4) The energy in the induction system initially is storied in the magnetic field when the switch is ON. That fact makes another benefit: a low voltage power supplies can be used. The reliability of a lower voltage power supply is higher and they are cheaper. (5) The coreless SLIM concept offers to work in the MHz range of repetition rate. The induction system has the high electric efficiency (much higher than the DWA). (6) The array of lined up and activated SLIM cells is believed to be a solid state structure of novel accelerating technology. The electron-hole plasma in the high power solid state structure is precisely controlled by the electromagnetic process of a pulsed power supply.

Krasnykh, A.; /SLAC; Kardo-Sysoev, A.; /Ioffe Phys. Tech. Inst.; Arntz, F.; /Diversified Tech., Bedford

2009-12-09

210

Maximizing Capture Efficiency and Specificity of Magnetic Separation for Mycobacterium avium subsp. paratuberculosis Cells ?  

PubMed Central

In order to introduce specificity for Mycobacterium avium subsp. paratuberculosis prior to a phage amplification assay, various magnetic-separation approaches, involving either antibodies or peptides, were evaluated in terms of the efficiency of capture (expressed as a percentage) of M. avium subsp. paratuberculosis cells and the percentage of nonspecific binding by other Mycobacterium spp. A 50:50 mixture of MyOne Tosylactivated Dynabeads coated with the chemically synthesized M. avium subsp. paratuberculosis-specific peptides biotinylated aMp3 and biotinylated aMptD (i.e., peptide-mediated magnetic separation [PMS]) proved to be the best magnetic-separation approach for achieving 85 to 100% capture of M. avium subsp. paratuberculosis and minimal (<1%) nonspecific recovery of other Mycobacterium spp. (particularly if beads were blocked with 1% skim milk before use) from broth samples containing 103 to 104 CFU/ml. When PMS was coupled with a recently optimized phage amplification assay and used to detect M. avium subsp. paratuberculosis in 50-ml volumes of spiked milk, the mean 50% limit of detection (LOD50) was 14.4 PFU/50 ml of milk (equivalent to 0.3 PFU/ml). This PMS-phage assay represents a novel, rapid method for the detection and enumeration of viable M. avium subsp. paratuberculosis organisms in milk, and potentially other sample matrices, with results available within 48 h. PMID:20851966

Foddai, Antonio; Elliott, Christopher T.; Grant, Irene R.

2010-01-01

211

Selective separation of lambdacyhalothrin by porous/magnetic molecularly imprinted polymers prepared by Pickering emulsion polymerization.  

PubMed

Porous/magnetic molecularly imprinted polymers (PM-MIPs) were prepared by Pickering emulsion polymerization. The reaction was carried out in an oil/water emulsion using magnetic halloysite nanotubes as the stabilizer instead of a toxic surfactant. In the oil phase, the imprinting process was conducted by radical polymerization of functional and cross-linked monomers, and porogen chloroform generated steam under the high reaction temperature, which resulted in some pores decorated with easily accessible molecular binding sites within the as-made PM-MIPs. The characterization demonstrated that the PM-MIPs were porous and magnetic inorganic-polymer composite microparticles with magnetic sensitivity (M(s) = 0.7448 emu/g), thermal stability (below 473 K) and magnetic stability (over the pH range of 2.0-8.0). The PM-MIPs were used as a sorbent for the selective binding of lambdacyhalothrin (LC) and rapidly separated under an external magnetic field. The Freundlich isotherm model gave a good fit to the experimental data. The adsorption kinetics of the PM-MIPs was well described by pseudo-second-order kinetics, indicating that the chemical process could be the rate-limiting step in the adsorption of LC. The selective recognition experiments exhibited the outstanding selective adsorption effect of the PM-MIPs for target LC. Moreover, the PM-MIPs regeneration without significant loss in adsorption capacity was demonstrated by at least four repeated cycles. PMID:23894024

Hang, Hui; Li, Chunxiang; Pan, Jianming; Li, Linzi; Dai, Jiangdong; Dai, Xiaohui; Yu, Ping; Feng, Yonghai

2013-10-01

212

Conjugates of magnetic nanoparticle-actinide specific chelator for radioactive waste separation.  

PubMed

A novel nanotechnology for the separation of radioactive waste that uses magnetic nanoparticles (MNPs) conjugated with actinide specific chelators (MNP-Che) is reviewed with a focus on design and process development. The MNP-Che separation process is an effective way of separating heat generating minor actinides (Np, Am, Cm) from spent nuclear fuel solution to reduce the radiological hazard. It utilizes coated MNPs to selectively adsorb the contaminants onto their surfaces, after which the loaded particles are collected using a magnetic field. The MNP-Che conjugates can be recycled by stripping contaminates into a separate, smaller volume of solution, and then become the final waste form for disposal after reusing number of times. Due to the highly selective chelators, this remediation method could be both simple and versatile while allowing the valuable actinides to be recovered and recycled. Key issues standing in the way of large-scale application are stability of the conjugates and their dispersion in solution to maintain their unique properties, especially large surface area, of MNPs. With substantial research progress made on MNPs and their surface functionalization, as well as development of environmentally benign chelators, this method could become very flexible and cost-effective for recycling used fuel. Finally, the development of this nanotechnology is summarized and its future direction is discussed. PMID:24070142

Kaur, Maninder; Zhang, Huijin; Martin, Leigh; Todd, Terry; Qiang, You

2013-11-01

213

Conjugates of Magnetic Nanoparticle -- Actinide Specific Chelator for Radioactive Waste Separation  

SciTech Connect

A novel nanotechnology for the separation of radioactive waste that uses magnetic nanoparticles (MNPs) conjugated with actinide specific chelators (MNP-Che) is reviewed with a focus on design and process development. The MNP-Che separation process is an effective way of separating heat generating minor actinides (Np, Am, Cm) from spent nuclear fuel solution to reduce the radiological hazard. It utilizes coated MNPs to selectively adsorb the contaminants onto their surfaces, after which the loaded particles are collected using a magnetic field. The MNP-Che conjugates can be recycled by stripping contaminates into a separate, smaller volume of solution, and then become the final waste form for disposal after reusing number of times. Due to the highly selective chelators, this remediation method could be both simple and versatile while allowing the valuable actinides to be recovered and recycled. Key issues standing in the way of large-scale application are stability of the conjugates and their dispersion in solution to maintain their unique properties, especially large surface area, of MNPs. With substantial research progress made on MNPs and their surface functionalization, as well as development of environmentally benign chelators, this method could become very flexible and cost-effective for recycling used fuel. Finally, the development of this nanotechnology is summarized and its future direction is discussed.

Maninder Kaur; Huijin Zhang; Leigh Martin; Terry Todd; You Qiang

2013-11-01

214

Controlled Synthesis of Fe3 O4 /ZIF-8 Nanoparticles for Magnetically Separable Nanocatalysts.  

PubMed

Fe3 O4 /ZIF-8 nanoparticles were synthesized through a room-temperature reaction between 2-methylimidazolate and zinc nitrate in the presence of Fe3 O4 nanocrystals. The particle size, surface charge, and magnetic loading can be conveniently controlled by the dosage of Zn(NO3 )2 and Fe3 O4 nanocrystals. The as-prepared particles show both good thermal stability (stable to 550?°C) and large surface area (1174?m(2) g(-1) ). The nanoparticles also have a superparamagnetic response, so that they can strongly respond to an external field during magnetic separation and disperse back into the solution after withdrawal of the magnetic field. For the Knoevenagel reaction, which is catalyzed by alkaline active sites on external surface of catalyst, small Fe3 O4 /ZIF-8 nanoparticles show a higher catalytic activity. At the same time, the nanocatalysts can be continuously used in multiple catalytic reactions through magnetic separation, activation, and redispersion with little loss of activity. PMID:25766136

Pang, Fei; He, Mingyuan; Ge, Jianping

2015-04-27

215

Cesium separation from contaminated milk using magnetic particles containing crystalline silicotitantes.  

SciTech Connect

The Chernobyl nuclear reactor disaster in 1986 contaminated vast regions of prime grazing land. Subsequently, milk produced in the region has been contaminated with small amounts of the long-lived fission product cesium-137, and the Ukraine is seeking to deploy a simple separation process that will remove the Cs and preserve the nutritional value of the milk. Tiny magnetic particles containing crystalline silicotitanates (CST) have been manufactured and tested to this end. The results show that partitioning efficiency is optimized with low ratios of particle mass to volume. To achieve 90% Cs decontamination in a single-stage process, <3 g of magnetic CST per l milk is sufficient with a 30-min mixing time. A two-stage process would utilize <0.4 g/l per stage. The modeling of the magnetic CST system described herein can be achieved rather simply which is important for deployment in the affected Ukraine region.

Nunez, L.; Kaminski, M.; Chemical Engineering

2000-11-01

216

Structural studies, magnetic properties and loss separation in iron–phenolicsilane soft magnetic composites  

Microsoft Academic Search

In this work, six different series of iron based soft magnetic composites are produced and studied: (1) passive iron powder; (2) passive iron powder-0.7% resin with coupling agent; (3) passive iron powder-0.7% resin without coupling agent; (4) passive iron powder-1.5% resin with coupling agent; (5) passive iron powder-1.5% resin without coupling agent; (6) pure iron-1.5% resin. The specimens were shaped

A. H. Taghvaei; H. Shokrollahi; K. Janghorban

2010-01-01

217

Particle Segregation in a Flowing Suspension Subject to High-Gradient Strong Electric Fields  

NASA Technical Reports Server (NTRS)

The widespread use of electro-hydrodynamic devices and processes emphasizes a critical need for developing a comprehensive predictive theory capable of improving our fundamental understanding of the behavior of a suspension subject to an AC electric field and shear, and of facilitating the design and optimization of such devices. The currently favored approach to the qualitative interpretation of the AC field driven manipulation of suspensions is based on a model which considers only the force exerted on a single particle by an external field and neglects the field-induced and hydrodynamic interparticle interactions both being inversely proportional to the interparticle distance raised to the power three. On the other hand, the purpose of the field-induced separation is to concentrate particles in certain regions of a device. This clearly raises the fundamental question regarding the extent to which we can neglect these slow decaying electrical and hydrodynamic collective interactions and rely on the predictions of a single-particle model. Another important issue that still remains open is how to characterize the polarization of a particle exposed to a strong electric field. The presentation will address both these questions. Experiments were conducted in a parallel-plate channel in which a 10(exp -3) (v/v) suspension of heavy, positively polarized Al2O3 spheres was exposed to an AC field under conditions such that the field lines were arranged in the channel cross-section perpendicular to the streamlines of the main flow. To reduce the effects of the gravitational settling of the particles, the channel was slowly rotated (4 rpm) around a horizontal axis. Following the application of a high-gradient strong AC field (approx. kV/mm), the particles were found to move towards both the high-voltage (HV) and grounded (GR) electrodes and to form 'bristles' along their edges.

Acrivos, Andreas; Qiu, Zhiyong; Khusid, Boris; Markarian, Nikolai

2002-01-01

218

Synthesis of magnetically separable Sn doped magnetite/silica core-shell structure and photocatalytic property  

SciTech Connect

Sn doped Fe{sub 3}O{sub 4}/SiO{sub 2} core-shell structures with the magnetic and photocatalytic properties have been successfully synthesized using Fe{sub 3}O{sub 4} microspheres as the precursor. The morphology, phase and structure of the bifunctional products were investigated by X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy. The effects of the amount and hydrolysis rate of tetraethyl orthosilicate on the preparation of the Fe{sub 3}O{sub 4}/SiO{sub 2} core-shell structures were investigated. Low concentration and slow hydrolysis rate of tetraethyl orthosilicate were useful to obtain the uniform silica coated Fe{sub 3}O{sub 4}. The magnetic measurements indicated that the Sn doped Fe{sub 3}O{sub 4}/SiO{sub 2} core-shell structures showed ferromagnetic property and the magnetic saturation value slightly decreased after coated the silica layer. The magnetic Sn doped Fe{sub 3}O{sub 4}/SiO{sub 2} core-shell structures exhibited good photocatalytic activity in the degradation of methyl orange and could be separated by applying an appropriate magnetic field.

Wang, Wei-Wei, E-mail: weiweiwangsd@yahoo.com.cn [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255049 (China)] [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255049 (China); Yao, Jia-Liang [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255049 (China)] [School of Materials Science and Engineering, Shandong University of Technology, 12 Zhang Zhou Road, Zibo, Shandong 255049 (China)

2010-06-15

219

THE DETECTION OF NUMEROUS MAGNETIC SEPARATORS IN A THREE-DIMENSIONAL MAGNETOHYDRODYNAMIC MODEL OF SOLAR EMERGING FLUX  

SciTech Connect

Magnetic separators in three-dimensional (3D) magnetic fields are believed to be often associated with locations of magnetic reconnection. In this preliminary study, we investigate this relationship using data from a numerical resistive 3D MHD experiment of a solar flux emergence event. For the first time separators are detected in complex magnetic fields resulting from a 3D resistive MHD model of flux emergence. Two snapshots of the model, taken from different stages of its evolution, are analyzed. Numerous separators are found in both snapshots, and their properties, including their geometry, length, relationship to the magnetic null points, and integrated parallel electric field are studied. The separators reside at the junctions between the emerging flux, the overlying field, and two other flux domains that are newly formed by reconnection. The long separators, which connect clusters of nulls that lie either side of the emerging flux, pass through spatially localized regions of high parallel electric field and correspond to local maxima in integrated parallel electric field. These factors indicate that strong magnetic reconnection takes place along many of the separators, and that separators play a key role during the interaction of emerging and overlying flux.

Parnell, C. E.; Maclean, R. C.; Haynes, A. L., E-mail: clare@mcs.st-and.ac.u [School of Mathematics and Statistics, University of St Andrews, The North Haugh, St Andrews, Fife, KY16 9SS (United Kingdom)

2010-12-20

220

An isobar separation method with Q3D magnetic spectrometer for AMS  

NASA Astrophysics Data System (ADS)

Isobar interference is the main obstacle for AMS measurement, especially in the case of very strong isobaric interference, such as in the measurement of 32Si, 53Mn, 60Fe, 63Ni, etc. An isobar separation method with Q3D magnetic spectrometer was developed aiming at AMS measurements for the above-mentioned nuclides. Based on a method of (?E-Q3D) the isobaric events can be largely rejected from the region of the nuclide of interest on the focal plane of a Q3D magnetic spectrometer. As a result, the isobaric interference can be reduced by more than three orders of magnitude. Further reduction of isobaric interference can be achieved by the use of a multi-anode ionization chamber placed at the position of collecting the nuclide of interest. The performance of the ?E-Q3D system for isobar separation was tested by the above-mentioned nuclides with atomic numbers from 14 to 42. The results showed that ?E-Q3D method has strong capability for separating isobars, as detailed in this paper.

Li, Chaoli; He, Ming; Jiang, Shan; Li, Shizhuo; Gong, Jie; Liu, Jiancheng; Wang, Wei; He, GuoZhu; Wu, Shaoyong; Dong, Kejun; Wang, Xianggao; Shen, Hongtao

2010-10-01

221

Experimental and theoretical investigation of high gradient acceleration. Progress report, June 1, 1991--February 1, 1992  

SciTech Connect

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. ``Experimental and Theoretical Investigations of High Gradient Acceleration.`` This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders. This report is organized as follows. The development of an rf gun design and research progress on the picosecond laser system is summarized in Sec. 2, the status of the studies of the LBL/Haimson high gradient structure, using a 50 MW free-electron laser is summarized in Sec. 3, and theoretical research progress is described in Sec. 4. Supporting material is contained in Appendices A-G.

Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R.J.; Wurtele, J.S.

1992-02-01

222

Three-dimensional modeling of a portable medical device for magnetic separation of particles from biological fluids.  

PubMed

A portable separator has been developed to quantitatively separate blood-borne magnetic spheres in potentially high-flow regimes for the human detoxification purpose. In the separator design, an array of biocompatible capillary tubing and magnetizable wires is immersed in an external magnetic field that is generated by two permanent magnets. The wires are magnetized and the high magnetic field gradient from the magnetized wires helps to collect blood-borne magnetic nano/micro-spheres from the blood flow. In this study, a 3D numerical model was created and the effect of tubing-wire configurations on the capture efficiency of the system was analyzed using COMSOL Multiphysics 3.3(R). The results showed that the configuration characterized by bi-directionally alternating wires and tubes was the best design with respect to the four starting configurations. Preliminary in vitro experiments verified the numerical predictions. The results helped us to optimize a prototype portable magnetic separator that is suitable for rapid sequestration of magnetic nano/micro-spheres from the human blood stream while accommodating necessary clinical boundary conditions. PMID:17762081

Chen, Haitao; Bockenfeld, Danny; Rempfer, Dietmar; Kaminski, Michael D; Rosengart, Axel J

2007-09-01

223

Non-isothermal separation of ferrofluid particles through grids: Abnormal magnetic Soret effect  

NASA Astrophysics Data System (ADS)

Nanoparticle transport through thin non-isothermal ferrofluid layer between permeable walls is investigated. The transient mass flux is determined from measurements of particle concentration changes in two fluid chambers of different temperatures which are attached on both sides of the layer. Experiments are performed employing fluid samples of small ordinary magnetic Soret effect, which is detected by thermal grating technique. The separation measurements say that a magnetic field, aligned along a temperature gradient, causes a remarkable increase in the mass diffusion coefficient and a simultaneous decrease in particle thermodiffusion mobility. It is proposed that the observed effects may be evoked by specific microconvective mass transfer induced by nonmagnetic grid elements of the permeable walls.

Blums, Elmars; Sints, Viesturs; Kronkalns, Gunars; Mezulis, Ansis

2013-04-01

224

Preparation of quantum dot-coated magnetic polystyrene nanospheres for cancer cell labelling and separation  

NASA Astrophysics Data System (ADS)

CdTe-coated magnetic polystyrene nanospheres (MPN) were prepared via a stepwise electrostatic self-assembly approach, and the conjugation of epidermal growth factor (EGF) to the MPN/CdTe core-shell nanocomposites was prepared by using 1-ethyl-3(3-dimethylamino propyl)-carbodiimide (EDC) as a cross-linking reagent. The MPN/CdTe and their bioconjugates yielded not only emitted bright fluorescence, but also exhibited superparamagnetism. The human breast cancer MDA-MB-435S cells could be labelled and rapidly separated by the MPN/CdTe-EGF bioconjugates. These magnetofluorescent nanospheres, consisting of magnetic spheres and quantum dots (QDs), may be of special interest for many biomedical applications.

Chu, Maoquan; Song, Xin; Cheng, Duo; Liu, Shupeng; Zhu, Jian

2006-07-01

225

Avian ultraviolet/violet cones as magnetoreceptors: The problem of separating visual and magnetic information.  

PubMed

In a recent paper, we described the localization of cryptochrome 1a in the retina of domestic chickens, Gallus gallus, and European robins, Erithacus rubecula: Cryptochrome 1a was found exclusively along the membranes of the disks in the outer segments of the ultraviolet/violet single cones. Cryptochrome has been suggested to act as receptor molecule for the avian magnetic compass, which would mean that the UV/V cones have a double function: they mediate vision in the short-wavelength range and, at the same time, magnetic directional information. This has important implications and raises a number of questions, in particular, how the two types of input are separated. Here, we point out several possibilities how this could be achieved.  PMID:22446535

Bischof, Hans-Joachim; Nießner, Christine; Peichl, Leo; Wiltschko, Roswitha; Wiltschko, Wolfgang

2011-11-01

226

Magnetic resonance assessment of iron overload by separate measurement of tissue ferritin and hemosiderin iron  

PubMed Central

With transfusional iron overload, almost all the excess iron is sequestered intracellularly as rapidly mobilizable, dispersed, soluble, ferritin iron, and as aggregated, insoluble hemosiderin iron for long-term storage. Established magnetic resonance imaging (MRI) indicators of tissue iron (R2, R2*) are principally influenced by hemosiderin iron and change slowly, even with intensive iron chelation. Intracellular ferritin iron is evidently in equilibrium with the low-molecular-weight cytosolic iron pool that can change rapidly with iron chelation. We have developed a new magnetic resonance imaging (MRI) method to separately measure ferritin and hemosiderin iron, based on the non-monoexponential signal decay induced by aggregated iron in multiple-spin-echo sequences. We have initially validated the method in agarose phantoms and in human liver explants and shown the feasibility of its application in patients with thalassemia major. Measurement of tissue ferritin iron is a promising new means to rapidly evaluate the effectiveness of iron-chelating regimens. PMID:20712781

Wu, Ed X.; Kim, Daniel; Tosti, Christina L.; Tang, Haiying; Jensen, Jens H.; Cheung, Jerry S.; Feng, Li; Au, Wing-Yan; Ha, Shau-Yin; Sheth, Sujit S.; Brown, Truman R.; Brittenham, Gary M.

2010-01-01

227

Chemical separation of primordial Li+ during structure formation caused by nanogauss magnetic field  

NASA Astrophysics Data System (ADS)

During the structure formation, charged and neutral chemical species may have separated from each other at the gravitational contraction in primordial magnetic field (PMF). A gradient in the PMF in a direction perpendicular to the field direction leads to the Lorentz force on the charged species. Resultantly, an ambipolar diffusion occurs, and charged species can move differently from neutral species, which collapses gravitationally during the structure formation. We assume a gravitational contraction of neutral matter in a spherically symmetric structure, and calculate fluid motions of charged and neutral species. It is shown that the charged fluid, i.e. proton, electron, and 7Li+, can significantly decouple from the neutral fluid depending on the field amplitude. The charged species can, therefore, escape from the gravitational collapse. We take the structure mass, the epoch of the gravitational collapse, and the comoving Lorenz force as parameters. We then identify a parameter region for an effective chemical separation. This type of chemical separation can reduce the abundance ratio of Li/H in early structures because of inefficient contraction of 7Li+ ion. Therefore, it may explain Li abundances of Galactic metal-poor stars which are smaller than the prediction in standard big bang nucleosynthesis model. Amplitudes of the PMFs are controlled by a magnetohydrodynamic turbulence. The upper limit on the field amplitude derived from the turbulence effect is close to the value required for the chemical separation.

Kusakabe, Motohiko; Kawasaki, Masahiro

2015-01-01

228

Simultaneous determination of ten organophosphate pesticide residues in fruits by gas chromatography coupled with magnetic separation.  

PubMed

In this study, ?-Fe2 O3 /chitosan magnetic microspheres were synthesized and evaluated by X-ray diffraction, SEM, thermogravimetric analysis, and static and kinetic adsorption experiments. Results showed that the magnetic microspheres exhibited good adsorption ability, and offered fast kinetics for the adsorption of trichlorfon, methamidophos, malathion, methyl parathion, dimethoate, omethoate, phosphamidon, phorate, isocarbophos, and chlorpyrifos. Based on magnetic separation, a simple method of magnetic SPE coupled to GC for the simultaneous determination of ten trace organophosphate pesticide residues was developed. Under the optimal conditions, the enrichment factor for ten organophosphorus pesticides was 10.1-364.7 and linear range was 0.001-10.0 mg/L. The LOD (S/N = 3) of the method for the ten pesticides was 0.31-3.59 ?g/kg. The RSD for three replicate extractions of spiked samples was between 2.5 and 6.3%. The pear and apple samples spiked with ten organophosphate pesticides at 20 and 200 ?g/kg levels were extracted and determined by this method with good recoveries ranging from 79.9 to 98.7%. Moreover, the method has been successfully applied for the determination of the ten organophosphate pesticide residues in peach samples. PMID:24470377

Tang, Qinghua; Wang, Xilong; Yu, Fan; Qiao, Xuguang; Xu, Zhixiang

2014-04-01

229

Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents  

DOEpatents

A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known pressure swing adsorption'' technique utilizing the same sorption material. 1 fig.

Judkins, R.R.; Burchell, T.D.

1999-07-20

230

Method and apparatus for separating gases based on electrically and magnetically enhanced monolithic carbon fiber composite sorbents  

DOEpatents

A method for separating gases or other fluids involves placing a magnetic field on a monolithic carbon fiber composite sorption material to more preferentially attract certain gases or other fluids to the sorption material to which a magnetic field is applied. This technique may be combined with the known "pressure swing adsorption" technique utilizing the same sorption material.

Judkins, Roddie R. (9917 Rainbow Dr., Knoxville, TN 37922); Burchell, Timothy D. (109 Greywood Pl., Oak Ridge, TN 37830)

1999-01-01

231

IMPROVEMENT OF MAGNETICALLY SEPARATED FERROUS CONCENTRATE BY SHREDDING: A PERFORMANCE TEST. TEST NO. 4.07, RECOVERY 1, NEW ORLEANS  

EPA Science Inventory

This report describes a series of test runs in which ferrous product magnetically recovered from municipal waste was further shredded in a small (50 hp) hammermill to free attached or entrapped contaminant. A belt magnet was then used to separate metal from the liberated contamin...

232

Dynamics of the latitude structure of the solar large-scale magnetic field at separate longitude intervals during 1915 - 1965  

Microsoft Academic Search

Dynamics of background magnetic fields has been studied on the basis of H-alpha synoptic charts for 1915 - 1965 at separate longitude intervals. Peculiarities of the polarity reversal of the magnetic field latitude migration of the zonal structures in dependence on the phase of the cycle is analyzed.

V. I. Makarov; M. V. Kushnir

1990-01-01

233

Brook trout (Salvelinus fontinalis) response to wood removal from high-gradient streams of the  

E-print Network

Brook trout (Salvelinus fontinalis) response to wood removal from high-gradient streams­impact study was conducted to evaluate brook trout (Salvelinus fontinalis) response to the removal of debris'omble de fontaine (Salvelinus fontinalis) au retrait de barrages et de débris ligneux dans un système de

Kraft, Clifford E.

234

Upgrading of PVC rich wastes by magnetic density separation and hyperspectral imaging quality control.  

PubMed

Polyvinylchloride (PVC) is one of the most produced polymers in Europe, with a share of 11% in terms of mass (8 milliontons) of total polymer consumption, but in 2010 only 5% of the total PVC production came from recycled materials, where other polymer recycling achieves a level of 15% on average. In order to find an innovative process to extract PVC from window frames waste, a combination of two innovative technologies was tested: magnetic density separation (MDS) and hyperspectral imaging (HSI). By its nature, MDS is a flexible high precision density separation technology that is applicable to any mixture of polymers and contaminants with non-overlapping densities. As PVC has a very distinctive high density, this technology was tested to obtain high-grade PVC pre-concentrates from window frame waste. HSI was used to perform a quality control of the products obtained by MDS showing that PVC was clearly discriminated from unwanted rubber particles of different colors. The results showed that the combined application of MDS and HSI techniques allowed to separate and to check the purity of PVC from window frame waste. PMID:25458764

Luciani, Valentina; Bonifazi, Giuseppe; Rem, Peter; Serranti, Silvia

2014-11-01

235

Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide  

NASA Astrophysics Data System (ADS)

We have studied local magnetic moment and electronic phase separation in superconducting KxFe2 -ySe2 by x-ray emission and absorption spectroscopy. Detailed temperature-dependent measurements at the Fe K-edge have revealed coexisting electronic phases and their correlation with the transport properties. By cooling down, the local magnetic moment of Fe shows a sharp drop across the superconducting transition temperature (Tc) and the coexisting phases exchange spectral weights with the low-spin state, gaining intensity at the expense of the higher-spin state. After annealing the sample across the iron-vacancy order temperature, the system does not recover the initial state and the spectral weight anomaly at Tc as well as superconductivity disappear. The results clearly underline that the coexistence of the low-spin and high-spin phases and the transitions between them provide unusual magnetic fluctuations and have a fundamental role in the superconducting mechanism of the electronically inhomogeneous KxFe2 -ySe2 system.

Simonelli, L.; Mizokawa, T.; Sala, M. Moretti; Takeya, H.; Mizuguchi, Y.; Takano, Y.; Garbarino, G.; Monaco, G.; Saini, N. L.

2014-12-01

236

Magnetism of perovskite oxides: The effect of strain and phase separation  

NASA Astrophysics Data System (ADS)

The magnetic properties of perovskite oxides can be affected by various conditions such as doping concentration, finite size limitation, and mechanical strain, which are associated with a range of intriguing physical phenomena in highly correlated electron systems such as colossal magnetoresistance, high temperature superconductivity, and phase inhomogeneities. In this thesis, we studied several topics concerning the cobaltates and nickelates which are associated with magnetism in perovskite oxides. La0.5Sr0.5CoO3 is a ferromagnetic material with Curie temperature TC of 250 K. In a form of thin films, we studied strain effect on its ferromagnetism. However, ferromagnetism in thin films is affected by both finite size effect and strain effect. We have used a series of films of different thicknesses and on different substrates to quantitatively determine the change in TC contributed by each effect. The phase diagram of TC versus in-plane strain suggests that TC is suppressed by tensile strain and enhanced by compressive strain. The general method of separating strain and finite thickness effects should be applicable to any ordering phase transition in thin films. The local structure of LSCO thin films was investigated by Extended X-ray Absorption Fine Structure technique. Our results suggest that the tensile strain elongates the Co-O bond length, while compressive strain shortens the bond length. The change of bond length is mainly responsible for the modulation of TC upon strain. This is contrary to assumptions generally used in literature on strained manganite films. Current double exchange model is not adequate to describe the ferromagnetic mechanism for cobaltate. In a case of no La, we studied the magnetic properties of SrCoO 2.5+x. SrCoO2.5 is an antiferromaget with Neel temperature of 570 K. With a starting material of SrCoO 2.88, we have carried out oxidization and reduction experiments through an electrochemical method. The hole doping introduced into SrCoO2.5 by oxygen has shown to play a crucial role in determining the materials' ferromagnetic characters such as Curie temperature, spin state, magnetic saturation moment, etc. A magnetic phase diagram of SrCoO2.5+x is thus proposed for the first time. The striking feature of the diagram is the existence of several line phases which contain antiferromagnetic and ferromagnetic phases. In high contrast with La1-ySryCoO 3, SrCoO2.5+x can be phase separated into a number of magnetic regions for which each one has a unique oxygen/hole concentration such as x = 0, 0.25, 0.375, and 0.5, respectively. Our results suggest that the mobile holes are playing a key role in ferromagnetism and phase separation in the system. For perovskite nickelate, we have successfully grown high-quality epitaxial La1.67Sr0.33NiO4 films using pulsed laser deposition. For the first time, the x-ray diffraction superlattice peaks associated with charge stripe phase have been successfully observed in films. By studying the evolution of the stripe phase as the film thicknesses are decreased, we provide direct evidence for suppression of the stripe phase in thinner samples with thicknesses of less than 2600 A. A scenario of short-range ordered stripes due to a lattice clamping effect is proposed to account for the suppression in light of a model of electronic stripe-glass.

Xie, Changkun

237

Wave-driven rotation and mass separation in rotating magnetic mirrors  

NASA Astrophysics Data System (ADS)

Axisymmetric mirrors are attractive for fusion because of their simplicity, high plasma pressure at a given magnetic pressure, and steady state operation. Their subclass, rotating mirrors, are particularly interesting because they have increased parallel confinement, magnetohydrodynamic stability, and a natural heating mechanism. This thesis finds and explores an unusual effect in supersonically rotating plasmas: particles are diffused by waves in both potential energy and kinetic energy. Extending the alpha channeling concept to rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A high azimuthal mode number perturbation on the magnetic field is a particularly simple way to achieve the latter effect. In the rotating frame, this perturbation is seen as a wave near the alpha particle cyclotron harmonic, and can break the azimuthal symmetry and magnetic moment conservation without changing the particles total energy. The particle may exit if it reduces its kinetic energy and becomes more trapped if it gains kinetic energy, leading to a steady state current that maintains the field. Simulations of single particles in rotating mirrors show that a stationary wave can extract enough energy from alpha particles for a reactor to be self-sustaining. In the same way, rotation can be produced in non-fusion plasmas. Waves are identified to produce rotation in plasma centrifuges, which separate isotopes based on their mass difference. Finally, a new high throughput mass filter which is well suited to separating nuclear waste is presented. The new filter, the magnetic centrifugal mass filter (MCMF), has well confined output streams and less potential for nuclear proliferation than competing technologies. To assess the usefulness of the MCMF, a metric for comparing mass filters is developed. With this metric, the MCMF is compared with other mass filters such as the Ohkawa filter and the conventional plasma centrifuge.

Fetterman, Abraham J.

238

Superparamagnetic magnesium ferrite nanoadsorbent for effective arsenic (III, V) removal and easy magnetic separation.  

PubMed

By doping a proper amount of Mg(2+) (~10%) into ?-Fe2O3 during a solvent thermal process, ultrafine magnesium ferrite (Mg0.27Fe2.50O4) nanocrystallites were successfully synthesized with the assistance of in situ self-formed NaCl "cage" to confine their crystal growth. Their ultrafine size (average size of ~3.7 nm) and relatively low Mg-content conferred on them a superparamagnetic behavior with a high saturation magnetization (32.9 emu/g). The ultrafine Mg0.27Fe2.50O4 nanoadsorbent had a high specific surface area of ~438.2 m(2)/g, and demonstrated a superior arsenic removal performance on both As(III) and As(V) at near neutral pH condition. Its adsorption capacities on As(III) and As(V) were found to be no less than 127.4 mg/g and 83.2 mg/g, respectively. Its arsenic adsorption mechanism was found to follow the inner-sphere complex mechanism, and abundant hydroxyl groups on its surface played the major role in its superior arsenic adsorption performance. It could be easily separated from treated water bodies with magnetic separation, and could be easily regenerated and reused while maintaining a high arsenic removal efficiency. This novel superparamagnetic magnesium ferrite nanoadsorbent may offer a simple single step adsorption treatment option to remove arsenic contamination from water without the pre-/post-treatment requirement for current industrial practice. PMID:23726698

Tang, Wenshu; Su, Yu; Li, Qi; Gao, Shian; Shang, Jian Ku

2013-07-01

239

Experimental and theoretical investigation of high gradient acceleration. Progress report, February 1, 1992--January 31, 1993  

SciTech Connect

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-AC02-91-ER40648, ``Experimental and Theoretical Investigations of High Gradient Acceleration``. This grant supports three research tasks: Task A consists of the design, fabrication and testing of a 17GHz RF photocathode gun, which can produce 2ps electron pulses with up to 1nC of charge at 2MeV energy and at a 1OHz repetition rate. Task B supports the testing of high gradient acceleration at 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tasks and on critical physics issues for the development of high energy linear colliders.

Wurtele, J.S.; Bekefi, G.; Chen, C.; Chen, S.C.; Temkin, R.J.

1993-01-01

240

Ultra-High Gradient S-Band Linac for Laboratory And Industrial Applications  

SciTech Connect

A strong demand for high gradient structures arises from the limited real estate available for linear accelerators. RadiaBeam Technologies is developing a Doubled Energy Compact Accelerator (DECA) structure: an S-band standing wave electron linac designed to operate at accelerating gradients of up to 50 MV/m. In this paper, we present the radio-frequency design of the DECA S-band accelerating structure, operating at 2.856 GHz in the {pi}-mode. The structure design is heavily influenced by NLC collaboration experience with ultra high gradient X-band structures; S-band, however, is chosen to take advantage of commonly available high power S-band klystrons.

Faillace, L.; /RadiaBeam Tech.; Agustsson, R.; /RadiaBeam Tech.; Dolgashev, V.; /SLAC; Frigola, P.; /RadiaBeam Tech.; Murokh, A.; /RadiaBeam Tech.; Rosenzweig, J.; /UCLA; Yakimenko, V.; /Brookhaven

2012-06-11

241

Ultra-High Gradient S-band Linac for Laboratory and Industrial Applications  

SciTech Connect

A strong demand for high gradient structures arises from the limited real estate available for linear accelerators. RadiaBeam Technologies is developing a Doubled Energy Compact Accelerator (DECA) structure: an S-band standing wave electron linac designed to operate at accelerating gradients of up to 50 MV/m. In this paper, we present the radio-frequency design of the DECA S-band accelerating structure, operating at 2.856 GHz in the {pi}-mode. The structure design is heavily influenced by NLC collaboration experience with ultra high gradient X-band structures; S-band, however, is chosen to take advantage of commonly available high power S-band klystrons.

Faillace, L.; Agustsson, R.; Frigola, P.; Murokh, A. [RadiaBeam Technologies, LLC., Santa Monica, CA 90404 (United States); Dolgashev, V. [Stanford Linear Accelerator Center, Menlo Park, CA 94025 (United States); Rosenzweig, J. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Yakimenko, V. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

2010-11-04

242

Summary report of working group 3: High gradient and laser-structure based acceleration  

SciTech Connect

The charge for the working group on high gradient and laser-structure based acceleration was to assess the current challenges involved in developing an advanced accelerator based on electromagnetic structures, and survey state-of-the-art methods to address those challenges. The topics of more than 50 presentations in the working group covered a very broad range of issues, from ideas, theoretical models and simulations, to design and manufacturing of accelerating structures and, finally, experimental results on obtaining extremely high accelerating gradients in structures from conventional microwave frequency range up to THz and laser frequencies. Workshop discussion topics included advances in the understanding of the physics of breakdown and other phenomena, limiting high gradient performance of accelerating structures. New results presented in this workshop demonstrated significant progress in the fields of conventional vacuum structure-based acceleration, dielectric wakefield acceleration, and laser-structure acceleration.

Solyak, N.; /Fermilab; Cowan, B.M.; /Tech-X, Boulder

2010-01-01

243

Ion Solid Interaction And Surface Modification At RF Breakdown In High-Gradient Linacs  

Microsoft Academic Search

Ion solid interactions have been shown to be an important new mechanism of unipolar arc formation in high-gradient rf linear accelerators through surface self-sputtering by plasma ions, in addition to an intense surface field evaporation. We believe a non-Debye plasma is formed in close vicinity to the surface and strongly affects surface atomic migration via intense bombardment by ions, strong

Zeke Insepov; Jim Norem; Seth Veitzer

2011-01-01

244

Technological Issues and High Gradient Test Results on X-Band Molybdenum Accelerating Structures  

SciTech Connect

Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC (Stanford Linear Accelerator Center) and KEK (Ko Enerugi Kasokuki Kenkyu Kiko). The technological issues to build both sections are discussed.

Spataro, B.; /LNF, Dafne Light; Alesini, D.; /LNF, Dafne Light; Chimenti, V.; /LNF, Dafne Light; Dolgashev, V.; /SLAC; Haase, A.; /SLAC; Tantawi, S.G.; /SLAC; Higashi, Y.; /KEK, Tsukuba; Marrelli, C.; /Rome U.; Mostacci, A.; /Rome U.; Parodi, R.; /INFN, Genoa; Yeremian, A.D.; /SLAC

2012-04-24

245

Design Studies of Nb3Sn High-Gradient Quadrupole Models for LARP  

Microsoft Academic Search

Insertion quadrupoles with large aperture and high gradient are required to achieve the luminosity upgrade goal of 1035 cm-2s-1 at the large hadron collider (LHC). In 2004, the US Department of Energy established the LHC accelerator research program (LARP) to develop a technology base for the upgrade. Nb3Sn conductor is required in order to operate at high field and with

GianLuca Sabbi; Nikolai Andreev; Shlomo Caspi; Daniel Dietderich; Paolo Ferracin; Arup Ghosh; Vadim Kashikhin; A. Lietzke; Alfred McInturff; Igor Novitski; Alexander Zlobin

2007-01-01

246

Large-scale superconducting separator for Kaolin processing  

SciTech Connect

Currently, high gradient magnetic separators (HGMSs) are used almost exclusively by the clay processing industry, particularly in producing an extremely white kaolin for the paper, coatings and rubber industries where a bright additive is desirable. As mined, the clay is a light cream color-not white. Many of these impurities can be removed chemically using a reducing agent such as sodium hydrosulfite in low pH, sulfuric acid, and alum. High purity, however, can be obtained by removing trace amounts of paramagnetic particles (100% finer than 2 {mu}m). This is accomplished by separating these particles from 28 wt% kaolin in a water slurry retaining them on magnetic wool, which is then periodically regenerated.

Winters, A.J, Jr. (Cryogenic Consultants, Inc. Allentown, PA (US)); Selvaggi, J.A. (Eriez Magnetics, Erie, PA (US))

1990-01-01

247

Templated synthesis of monodisperse mesoporous maghemite/silica microspheres for magnetic separation of genomic DNA  

NASA Astrophysics Data System (ADS)

A novel method is described for the preparation of superparamagnetic mesoporous maghemite (?-Fe 2O 3)/silica (SiO 2) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe 3O 4) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe 3O 4 to ?-Fe 2O 3 by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 °C feature spherical shape and uniform particle size ( dparticle=1.72 ?m), high saturation magnetization ( Ms=17.22 emu/g), superparamagnetism ( Mr/ Ms=0.023), high surface area ( SBET=240 m 2/g), and mesoporosity ( dpore=6.62 nm). The composite microsphere consists of interlocked amorphous SiO 2 nanoparticles, in which cubic ?-Fe 2O 3 nanocrystals are homogeneously dispersed and thermally stable against ?- to ?-phase transformation at temperatures up to 600 °C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phase adsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A260/ A280 values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

Chen, Feng; Shi, Ruobing; Xue, Yun; Chen, Lei; Wan, Qian-Hong

2010-08-01

248

Blood progenitor cell separation from clinical leukapheresis product by magnetic nanoparticle binding and magnetophoresis.  

PubMed

Positive selection of CD34+ blood progenitor cells from circulation has been reported to improve patient recovery in applications of autologous transplantation. Current magnetic separation methods rely on cell capture and release on solid supports rather than sorting from flowing suspensions, which limits the range of therapeutic applications and the process scale up. We tested CD34+ cell immunomagnetic labeling and isolation from fresh leukocyte fraction of peripheral blood (leukapheresis) using the continuous quadrupole magnetic flow sorter (QMS), consisting of a flow channel (SHOT, Greenville, IN) and a quadrupole magnet with a maximum field intensity (B(o)) of 1.42 T and a mean force field strength (S(m)) of 1.45 x 10(8) TA/m(2). Both the sample magnetophoretic mobility (m) and the inlet and outlet flow patterns highly affect the QMS performance. Seven commercial progenitor cell labeling reagent combinations were quantitatively evaluated by measuring magnetophoretic mobility of a high CD34 expression cell line, KG-1a, using the cell tracking velocimeter (CTV). The CD34 Progenitor Cell Isolation Kit (Miltenyi Biotec, Bergisch Gladbach, Germany) showed the strongest labeling of KG-1a cells and was selected for progenitor cell enrichment from 11 fresh and 11 cryopreserved clinical leukapheresis samples derived from different donors. The CD34+ cells were isolated with a purity of 60-96%, a recovery of 18-60%, an enrichment rate of 12-169, and a throughput of (1.7-9.3) x 10(4) cells/s. The results also showed a highly regular dependence of the QMS performance on the flow conditions that agreed with the theoretical predictions based on the CD34+ cell magnetophoretic mobility. PMID:17009321

Jing, Ying; Moore, Lee R; Williams, P Stephen; Chalmers, Jeffrey J; Farag, Sherif S; Bolwell, Brian; Zborowski, Maciej

2007-04-15

249

Vector-current correlation and charge separation via the chiral-magnetic effect  

NASA Astrophysics Data System (ADS)

We investigate the vector-current correlation ??? (VCC) in the presence of a strong external magnetic field (B=B0z^) at low temperature (T?Tc?) with P and CP violations, indicated by the nonzero chiral-chemical potential (???0), i.e. the chiral-magnetic effect (CME). For this purpose, we employ the instanton-vacuum configuration at finite T with nonzero topological charge (Qt?0). We also consider a simple estimation for the nonzero-mode contributions to the quark propagator, in addition to the zero-mode approximation. From the numerical calculations, it turns out that the longitudinal component of the connected VCC is linear in B0 and shows a bump, representing a corresponding vector meson at |Q|=(300˜400)MeV for T=0. The bump becomes enhanced as T increases and the bump position shifts to a lager |Q| value. In the limit of |Q|?0, the transverse component of the connected VCC disappears, whereas the longitudinal one remains finite and becomes insensitive to B0 with respect to T, due to diluting instanton contributions. Considering the simple collision geometry of heavy-ion collision and some assumptions on the induced magnetic field and screening effect, we can estimate the charge separation as a function of centrality using the present results for the VCC. The numerical results show a qualitative agreement with experiments for the Au+Au and Cu+Cu collisions. These results are almost independent on the source of the CME, instanton, or sphaleron, as long as the CME current is linear in B0.

Nam, Seung-Il

2010-08-01

250

TERA high gradient test program of RF cavities for medical linear accelerators  

NASA Astrophysics Data System (ADS)

The scientific community and the medical industries are putting a considerable effort into the design of compact, reliable and cheap accelerators for hadrontherapy. Up to now only circular accelerators are used to deliver beams with energies suitable for the treatment of deep seated tumors. The TERA Foundation has proposed and designed a hadrontherapy facility based on the cyclinac concept: a high gradient linear accelerator placed downstream of a cyclotron used as an injector. The overall length of the linac, and therefore its final cost, is almost inversely proportional to the average accelerating gradient achieved in the linac. TERA, in collaboration with the CLIC RF group, has started a high gradient test program. The main goal is to study the high gradient behavior of prototype cavities and to determine the appropriate linac operating frequency considering important issues such as machine reliability and availability of distributed power sources. A preliminary test of a 3 GHz cavity has been carried out at the beginning of 2010, giving encouraging results. Further investigations are planned before the end of 2011. A set of 5.7 GHz cavities is under production and will be tested in a near future. The construction and test of a multi-cell structure is also foreseen.

Degiovanni, A.; Amaldi, U.; Bonomi, R.; Garlasché, M.; Garonna, A.; Verdú-Andrés, S.; Wegner, R.

2011-11-01

251

GEOPHYSICS, VOL. 63, NO. 2 (MARCH-APRIL 1998); P. 431439, 13 FIGS. Separation of regional and residual magnetic field data  

E-print Network

is concerned with gravity data, but many of the methods can be extended to magnetic data processing and residual magnetic field data Yaoguo Li and Douglas W. Oldenburg ABSTRACT Wepresentamethodforseparatingregionalandresid- ual magnetic fields using a 3-D magnetic inversion al- gorithm. The separation is achieved

Oldenburg, Douglas W.

252

Fabrication of anisotropic porous silica monoliths by means of magnetically controlled phase separation in sol-gel processes.  

PubMed

Sol-gel accompanied by phase separation is an established method for the preparation of porous silica monoliths with well-defined macroporosity, which find numerous applications. In this work, we demonstrate how the addition of (superpara)magnetic nanocolloids as templates to a system undergoing a sol-gel transition with phase separation leads to the creation of monoliths with a strongly anisotropic structure. It is known that magnetic nanocolloids respond to the application of an external magnetic field by self-assembling into columnar structures. The application of a magnetic field during the chemically driven spinodal decomposition induced by the sol-gel transition allows one to break the symmetry of the system and promote the growth of elongated needle-like silica domains incorporating the magnetic nanocolloids, aligned in the direction of the field. It is found that this microstructure imparts a strong mechanical anisotropy to the materials, with a ratio between the Young's modulus values measured in a direction parallel and perpendicular to the one of the field as high as 150, and an overall smaller average macropores size as compared to isotropic monoliths. The microstructure and properties of the porous monoliths can be controlled by changing both the system composition and the strength of the applied magnetic field. Our monoliths represent the first example of materials prepared by magnetically controlling a phase transition occurring via spinodal decomposition. PMID:22849804

Furlan, Marco; Lattuada, Marco

2012-08-28

253

In situ magnetic separation of antibody fragments from Escherichia coli in complex media  

PubMed Central

Background In situ magnetic separation (ISMS) has emerged as a powerful tool to overcome process constraints such as product degradation or inhibition of target production. In the present work, an integrated ISMS process was established for the production of his-tagged single chain fragment variable (scFv) D1.3 antibodies (“D1.3”) produced by E. coli in complex media. This study investigates the impact of ISMS on the overall product yield as well as its biocompatibility with the bioprocess when metal-chelate and triazine-functionalized magnetic beads were used. Results Both particle systems are well suited for separation of D1.3 during cultivation. While the triazine beads did not negatively impact the bioprocess, the application of metal-chelate particles caused leakage of divalent copper ions in the medium. After the ISMS step, elevated copper concentrations above 120 mg/L in the medium negatively influenced D1.3 production. Due to the stable nature of the model protein scFv D1.3 in the biosuspension, the application of ISMS could not increase the overall D1.3 yield as was shown by simulation and experiments. Conclusions We could demonstrate that triazine-functionalized beads are a suitable low-cost alternative to selectively adsorb D1.3 fragments, and measured maximum loads of 0.08 g D1.3 per g of beads. Although copper-loaded metal-chelate beads did adsorb his-tagged D1.3 well during cultivation, this particle system must be optimized by minimizing metal leakage from the beads in order to avoid negative inhibitory effects on growth of the microorganisms and target production. Hereby, other types of metal chelate complexes should be tested to demonstrate biocompatibility. Such optimized particle systems can be regarded as ISMS platform technology, especially for the production of antibodies and their fragments with low stability in the medium. The proposed model can be applied to design future ISMS experiments in order to maximize the overall product yield while the amount of particles being used is minimized as well as the number of required ISMS steps. PMID:23688064

2013-01-01

254

Enhanced magnetic separation and photocatalytic activity of nitrogen doped titania photocatalyst supported on strontium ferrite.  

PubMed

An enhanced ferromagnetic property, visible light active TiO(2) photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe(12)O(19)) onto TiO(2) doped with nitrogen (N) and compared with N-doped TiO(2). The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO(2) supported on SrFe(12)O(19). The supported N-TiO(2) exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO(2). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO(2) and >85% degradation N-TiO(2), respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery ? 98% for further reuse. PMID:22100220

Abd Aziz, Azrina; Yong, Kok Soon; Ibrahim, Shaliza; Pichiah, Saravanan

2012-01-15

255

Steady-State Theory of a Discharge Column in a Magnetic Field: Separable Solutions for a Finite Cylinder  

Microsoft Academic Search

The problem of the steady state of a magnetized discharge of the positive column type, in the case of a finite cylinder, is shown to have separable solutions for the radial and axial dependence of plasma density, potential, and electron and ion velocities. Consequently, the results of the corresponding one-dimensional theory may be directly applied to the two-dimensional case. In

D. B. Ilic´; S. A. Self

1972-01-01

256

Magnetically separable nanocomposites with photocatalytic activity under visible light for the selective transformation of biomass-derived platform molecules  

EPA Science Inventory

Novel magnetically separable TiO2-guanidine-(Ni,Co)Fe2O4 nanomaterials were prepared and characterised by a series of techniques including XRD, SEM, TEM, N2 physisorption as well as XPS and subsequently tested for their photocatalytic activities in the selective transformation of...

257

Magnetic hetero-flocculation of paramagnetic colloidal particles  

SciTech Connect

The feasibility of a high-gradient magnetic separation process, utilizing magnetite as the energizable element in lieu of stainless steel wool, is evaluated by means of an equilibrium, two-particle, magnetic hetero-flocculation model. The model calculates the net force, defined as the sum of the magnetic, electrostatic, and van der Waals forces, exerted on a paramagnetic nanoparticle that is in the proximity of a fixed magnetite particle. Since the nanoparticle-magnetite system is assumed to be in direct contact with the moving fluid, the influence of the hydrodynamic force on the magnetic attractive force between the two particles is also explored. This model clearly reveals the ranges and conditions over which each of these various forces contributes to the net force relative to Brownian (thermal) motion. The model also reveals the feasibility of using magnetite particles instead of stainless steel as the energizable element for high-gradient magnetic separation. Important variables investigated include the size and surface charge of the particles, the magnetic field, the flow velocity, the electrolyte concentration, and the magnetic susceptibility of the nanoparticle.

Ebner, A.D.; Ritter, J.A.; Ploehn, H.J.

2000-05-01

258

Method and apparatus for fabrication of high gradient insulators with parallel surface conductors spaced less than one millimeter apart  

DOEpatents

Optical patterns and lithographic techniques are used as part of a process to embed parallel and evenly spaced conductors in the non-planar surfaces of an insulator to produce high gradient insulators. The approach extends the size that high gradient insulating structures can be fabricated as well as improves the performance of those insulators by reducing the scale of the alternating parallel lines of insulator and conductor along the surface. This fabrication approach also substantially decreases the cost required to produce high gradient insulators.

Sanders, David M. (Livermore, CA); Decker, Derek E. (Livermore, CA)

1999-01-01

259

Ferrimagnetism and magnetic phase separation in Nd1-xYxMnO3 studied by magnetization and high frequency electron paramagnetic resonance  

NASA Astrophysics Data System (ADS)

Ferrimagnetism and metamagnetic features tunable by composition are observed in the magnetic response of Nd1-xYxMnO3, for x=0.1-0.5. For all values of x in the series, the compound crystallizes in orthorhombic Pbnm space group similar to NdMnO3. Magnetization studies reveal a phase transition of the Mn-sublattice below T N Mn ? 80 K for all compositions, which, decreases up on diluting the Nd-site with Yttrium. For x=0.35, ferrimagnetism is observed. At 5 K, metamagnetic transition is observed for all compositions x < 0.4. The evolution of magnetic ground states and appearance of ferrimagnetism in Nd1-xYxMnO3 can be accounted for by invoking the scenario of magnetic phase separation. The high frequency electron paramagnetic resonance measurements on x=0.4 sample, which is close to the critical composition for phase separation, revealed complex temperature dependent lineshapes clearly supporting the assumption of magnetic phase separation.

Nair, Harikrishnan S.; Yadav, Ruchika; Adiga, Shilpa; Rao, S. S.; van Tol, Johan; Elizabeth, Suja

2015-01-01

260

Synthesis, characterization and photocatalytic activity of magnetically separable hexagonal Ni/ZnO nanostructure.  

PubMed

The hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure photocatalyst has successfully been prepared by the reduction of nickel chloride hexahydrate using hydrazine hydrate through the solvothermal process at 140 °C followed by surface modification of the product by the reflux method at 110 °C for 1 h. The X-ray diffraction (XRD) pattern showed that the 'as prepared' sample consists of face centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused. PMID:22975724

Senapati, Samarpita; Srivastava, Suneel K; Singh, Shiv B

2012-10-21

261

On-chip magnetic separation and encapsulation of cells in droplets.  

PubMed

Single cell study is gaining importance because of the cell-to-cell variation that exists within cell population, even after significant initial sorting. Analysis of such variation at the gene expression level could impact single cell functional genomics, cancer, stem-cell research, and drug screening. The on-chip monitoring of individual cells in an isolated environment would prevent cross-contamination, provide high recovery yield, and enable study of biological traits at a single cell level. These advantages of on-chip biological experiments is a significant improvement for a myriad of cell analyses methods, compared to conventional methods, which require bulk samples and provide only averaged information on cell structure and function. We report on a device that integrates a mobile magnetic trap array with microfluidic technology to provide the possibility of separation of immunomagnetically labeled cells and their encapsulation with reagents into picoliter droplets for single cell analysis. The simultaneous reagent delivery and compartmentalization of the cells immediately following sorting are all performed seamlessly within the same chip. These steps offer unique advantages such as the ability to capture cell traits as originated from its native environment, reduced chance of contamination, minimal use of the reagents, and tunable encapsulation characteristics independent of the input flow. Preliminary assay on cell viability demonstrates the potential for the device to be integrated with other up- or downstream on-chip modules to become a powerful single-cell analysis tool. PMID:23370785

Chen, Aaron; Byvank, Tom; Chang, Woo-Jin; Bharde, Atul; Vieira, Greg; Miller, Brandon L; Chalmers, Jeffrey J; Bashir, Rashid; Sooryakumar, Ratnasingham

2013-03-21

262

The synthesis, characterization and application of iron oxide nanocrystals in magnetic separations for arsenic and uranium removal  

NASA Astrophysics Data System (ADS)

Arsenic and uranium in the environment are hazardous to human health and require better methods for detection and remediation. Nanocrystalline iron oxides offer a number of advantages as sorbents for water purification and environmental remediation. First, highly uniform and crystalline iron oxide nanocrystals (nMAG) were prepared using thermal decomposition of iron salts in organic solutions; for the applications of interest in this thesis, a central challenge was the adaptation of these conventional synthetic methods to the needs of low infrastructure and economically disadvantaged settings. We show here that it is possible to form highly uniform and magnetically responsive nanomaterials using starting reagents and equipment that are readily available and economical. The products of this approach, termed the 'Kitchen Synthesis', are of comparable quality and effectiveness to laboratory materials. The narrow size distributions of the iron oxides produced in the laboratory synthesis made it possible to study the size-dependence of the magnetic separation efficiency of nanocrystals; generally as the diameter of particles increased they could be removed under lower applied magnetic fields. In this work we take advantage of this size-dependence to use magnetic separation as a tool to separate broadly distributed populations of magnetic materials. Such work makes it possible to use these materials in multiplexed separation and sensing schemes. With the synthesis and magnetic separation studies of these materials completed, it was possible to optimize their applications in water purification and environmental remediation. These materials removed both uranium and arsenic from contaminated samples, and had remarkably high sorption capacities --- up to 12 wt% for arsenic and 30 wt% for uranium. The contaminated nMAG is removed from the drinking water by either retention in a sand column, filter, or by magnetic separation. The uranium adsorption process was also utilized for the enhanced detection of uranium in environmental matrices. By relying on alpha-particle detection in well-formed and dense nMAG films, it was possible to improve soil detection of uranium by more than ten-thousand-fold. Central for this work was a detailed understanding of the chemistry at the iron oxide interface, and the role of the organic coatings in mediating the sorption process.

Mayo, John Thomas

263

Relativistic klystron driven compact high gradient accelerator as an injector to an X-ray synchrotron radiation ring  

DOEpatents

A compact high gradient accelerator driven by a relativistic klystron is utilized to inject high energy electrons into an X-ray synchrotron radiation ring. The high gradients provided by the relativistic klystron enables accelerator structure to be much shorter (typically 3 meters) than conventional injectors. This in turn enables manufacturers which utilize high energy, high intensity X-rays to produce various devices, such as computer chips, to do so on a cost effective basis.

Yu, David U. L. (1912 MacArthur St., Rancho Palos Verdes, CA 90732)

1990-01-01

264

Boundary-value problem for a counterrotating electrical discharge in an axial magnetic field. [plasma centrifuge for isotope separation  

NASA Technical Reports Server (NTRS)

An electrical discharge between two ring electrodes embedded in the mantle of a cylindrical chamber is considered, in which the plasma in the anode and cathode regions rotates in opposite directions under the influence of an external axial magnetic field. The associated boundary-value problem for the coupled partial differential equations describing the azimuthal velocity and radial current-density fields is solved in closed form. The velocity, current density, induced magnetic induction, and electric fields are presented for typical Hartmann numbers, magnetic Reynolds numbers, and geometry parameters. The discharge is shown to produce anodic and cathodic plasma sections rotating at speeds of the order 1,000,000 cm/sec for conventional magnetic field intensities. Possible application of the magnetoactive discharge as a plasma centrifuge for isotope separation is discussed.

Hong, S. H.; Wilhelm, H. E.

1978-01-01

265

Synthesis, characterization and photocatalytic activity of magnetically separable hexagonal Ni/ZnO nanostructure  

NASA Astrophysics Data System (ADS)

The hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure photocatalyst has successfully been prepared by the reduction of nickel chloride hexahydrate using hydrazine hydrate through the solvothermal process at 140 °C followed by surface modification of the product by the reflux method at 110 °C for 1 h. The X-ray diffraction (XRD) pattern showed that the `as prepared' sample consists of face centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused.The hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure photocatalyst has successfully been prepared by the reduction of nickel chloride hexahydrate using hydrazine hydrate through the solvothermal process at 140 °C followed by surface modification of the product by the reflux method at 110 °C for 1 h. The X-ray diffraction (XRD) pattern showed that the `as prepared' sample consists of face centered cubic Ni and hexagonal wurtzite ZnO without any traces of impurity. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images confirmed the formation of nickel nanoparticles under solvothermal conditions. These nickel nanoparticles, when subjected to reflux, formed the hexagonal zinc oxide coated nickel nanostructure. Fourier transform infrared (FTIR) spectra, photoluminescence (PL) and Raman studies also confirmed the presence of zinc oxide in the hybrid nanostructure. The growth mechanism for the development of the hexagonal zinc oxide coated nickel (Ni/ZnO) nanostructure has also been proposed. The appearance of the hysteresis loop, in the as-prepared Ni/ZnO hybrid nanostructure, demonstrated its ferromagnetic character at room temperature. The hexagonal Ni/ZnO nanostructure also acts as an efficient photocatalyst in the degradation of methylene blue under ultraviolet light irradiation. It is observed that the catalytic efficiency of the hybrid nanocatalyst is better compared to pure zinc oxide. Most importantly, the Ni/ZnO catalyst could also be easily separated, simply by applying an external magnetic field, and reused. Electronic supplementary information (ESI) available: Fig. S1 Ni/ZnO hybrid nanostructure prepared using (a) 0.195 and (b) 0.25 M [Zn2+] at 90 °C Fig. S2 FTIR spectra of nickel nanoparticles prepared at 140 °C (a), and Ni/ZnO hybrid nanostructure prepared using (b) 0.063, (c) 0.125, (d) 0.195 and (e) 0.25 M [Zn2+]; Fig. S3 Raman spectra of Ni/ZnO nanostructure prepared using (a) 0.063, (b) 0.125, (c) 0.195 and (d) 0.25 M [Zn2+]; Fig. S4 Room temperature PL spectra of (a) ZnO and (b) Ni/ZnO nanostructure prepared using 0.25 M [Zn2+]. See DOI: 10.1039/c2nr31831h

Senapati, Samarpita; Srivastava, Suneel K.; Singh, Shiv B.

2012-09-01

266

Separation Anxiety  

NSDL National Science Digital Library

In this activity, learners discover the primary physical properties used to separate pure substances from mixtures. Learners use test tubes, beakers, magnets, and other tools to separate a mixture of sand, iron filings, salt, popcorn kernels, and poppyseeds. This activity introduces learners to the basic properties of size, magnetism, density and solubility while emphasizing that chemistry involves separating out substances either to understand what they are or to use the pure components to create new substances.

Julie Yu

2007-01-01

267

Separation and correlation of structural and magnetic roughness in a Ni thin film by polarized off-specular neutron reflectometry.  

PubMed

Diffuse (off-specular) neutron and x-ray reflectometry has been used extensively for the determination of interface morphology in solids and liquids. For neutrons, a novel possibility is off-specular reflectometry with polarized neutrons to determine the morphology of a magnetic interface. There have been few such attempts due to the lower brilliance of neutron sources, though magnetic interaction of neutrons with atomic magnetic moments is much easier to comprehend and easily tractable theoretically. We have obtained a simple and physically meaningful expression, under the Born approximation, for analyzing polarized diffuse (off-specular) neutron reflectivity (PDNR) data. For the first time PDNR data from a Ni film have been analyzed and separate chemical and magnetic morphologies have been quantified. Also specular polarized neutron reflectivity measurements have been carried out to measure the magnetic moment density profile of the Ni film. The fit to PDNR data results in a longer correlation length for in-plane magnetic roughness than for chemical (structural) roughness. The magnetic interface is smoother than the chemical interface. PMID:21817297

Singh, Surendra; Basu, Saibal

2009-02-01

268

Continuous sheath-free magnetic separation of particles in a U-shaped microchannel  

E-print Network

in microfluidic devices, among which electric,1,2 magnetic,3,4 acoustic,5,6 and opti- cal7,8 forces are the most issues (if permanent magnets are used) which accom- pany nearly all other methods, and is therefore well, an external magnetic force acts on the suspended particles and deflects them to different flow paths

Xuan, Xiangchun "Schwann"

269

Towards an electro-magnetic field separation of deposited material implemented in an ion beam sputter process  

SciTech Connect

Nowadays, Ion Beam Sputter (IBS) processes are very well optimized on an empirical basis. To achieve further progresses, a modification of the IBS process by guiding the coating material using an axial magnetic field and an additional electrical field has been studied. The electro-magnetic (EM) field leads to a significant change in plasma properties and deposition rate distributions, whereas an increase in deposition rate along the centerline of the axial EM field around 150% was observed. These fundamental studies on the prototype are the basis for the development of an applicable and workable design of a separation device.

Malobabic, Sina; Jupe, Marco; Ristau, Detlev [Laser Component Department, Laser Zentrum Hannover e.V., Hollerithallee 8, 30149 Hannover (Germany) [Laser Component Department, Laser Zentrum Hannover e.V., Hollerithallee 8, 30149 Hannover (Germany); Quest: Centre of Quantum Engineering and Space-Time Research, Leibniz Universitaet Hannover, Hannover (Germany)

2013-06-03

270

Magnetically activated and guided isotope separation This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

inefficient due to the low probability of electron-bombardment ionization. Later, laser isotope separation (LIS) was proposed [5]. In recent years isotope separation by laser ionization (AVLIS) has beenMagnetically activated and guided isotope separation This article has been downloaded from

Raizen, Mark G.

271

Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC  

E-print Network

Local parity-odd domains are theorized to form inside a Quark-Gluon-Plasma (QGP) which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect (CME). The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this paper, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy, and tends to vanish by 7.7 GeV. The implications of these results for the CME will be discussed.

STAR Collaboration; L. Adamczyk; J. K. Adkins; G. Agakishiev; M. M. Aggarwal; Z. Ahammed; I. Alekseev; J. Alford; C. D. Anson; A. Aparin; D. Arkhipkin; E. C. Aschenauer; G. S. Averichev; A. Banerjee; D. R. Beavis; R. Bellwied; A. Bhasin; A. K. Bhati; P. Bhattarai; H. Bichsel; J. Bielcik; J. Bielcikova; L. C. Bland; I. G. Bordyuzhin; W. Borowski; J. Bouchet; A. V. Brandin; S. G. Brovko; S. Bültmann; I. Bunzarov; T. P. Burton; J. Butterworth; H. Caines; M. Calderón de la Barca Sánchez; D. Cebra; R. Cendejas; M. C. Cervantes; P. Chaloupka; Z. Chang; S. Chattopadhyay; H. F. Chen; J. H. Chen; L. Chen; J. Cheng; M. Cherney; A. Chikanian; W. Christie; J. Chwastowski; M. J. M. Codrington; G. Contin; J. G. Cramer; H. J. Crawford; X. Cui; S. Das; A. Davila Leyva; L. C. De Silva; R. R. Debbe; T. G. Dedovich; J. Deng; A. A. Derevschikov; R. Derradi de Souza; S. Dhamija; B. di Ruzza; L. Didenko; C. Dilks; F. Ding; P. Djawotho; X. Dong; J. L. Drachenberg; J. E. Draper; C. M. Du; L. E. Dunkelberger; J. C. Dunlop; L. G. Efimov; J. Engelage; K. S. Engle; G. Eppley; L. Eun; O. Evdokimov; O. Eyser; R. Fatemi; S. Fazio; J. Fedorisin; P. Filip; E. Finch; Y. Fisyak; C. E. Flores; C. A. Gagliardi; D. R. Gangadharan; D. Garand; F. Geurts; A. Gibson; M. Girard; S. Gliske; L. Greiner; D. Grosnick; D. S. Gunarathne; Y. Guo; A. Gupta; S. Gupta; W. Guryn; B. Haag; A. Hamed; L-X. Han; R. Haque; J. W. Harris; S. Heppelmann; A. Hirsch; G. W. Hoffmann; D. J. Hofman; S. Horvat; B. Huang; H. Z. Huang; X. Huang; P. Huck; T. J. Humanic; G. Igo; W. W. Jacobs; H. Jang; E. G. Judd; S. Kabana; D. Kalinkin; K. Kang; K. Kauder; H. W. Ke; D. Keane; A. Kechechyan; A. Kesich; Z. H. Khan; D. P. Kikola; I. Kisel; A. Kisiel; D. D. Koetke; T. Kollegger; J. Konzer; I. Koralt; L. K. Kosarzewski; L. Kotchenda; A. F. Kraishan; P. Kravtsov; K. Krueger; I. Kulakov; L. Kumar; R. A. Kycia; M. A. C. Lamont; J. M. Landgraf; K. D. Landry; J. Lauret; A. Lebedev; R. Lednicky; J. H. Lee; M. J. LeVine; C. Li; W. Li; X. Li; X. Li; Y. Li; Z. M. Li; M. A. Lisa; F. Liu; T. Ljubicic; W. J. Llope; M. Lomnitz; R. S. Longacre; X. Luo; G. L. Ma; Y. G. Ma; D. M. M. D. Madagodagettige Don; D. P. Mahapatra; R. Majka; S. Margetis; C. Markert; H. Masui; H. S. Matis; D. McDonald; T. S. McShane; N. G. Minaev; S. Mioduszewski; B. Mohanty; M. M. Mondal; D. A. Morozov; M. K. Mustafa; B. K. Nandi; Md. Nasim; T. K. Nayak; J. M. Nelson; G. Nigmatkulov; L. V. Nogach; S. Y. Noh; J. Novak; S. B. Nurushev; G. Odyniec; A. Ogawa; K. Oh; A. Ohlson; V. Okorokov; E. W. Oldag; D. L. Olvitt Jr.; M. Pachr; B. S. Page; S. K. Pal; Y. X. Pan; Y. Pandit; Y. Panebratsev; T. Pawlak; B. Pawlik; H. Pei; C. Perkins; W. Peryt; P. Pile; M. Planinic; J. Pluta; N. Poljak; K. Poniatowska; J. Porter; A. M. Poskanzer; N. K. Pruthi; M. Przybycien; P. R. Pujahari; J. Putschke; H. Qiu; A. Quintero; S. Ramachandran; R. Raniwala; S. Raniwala; R. L. Ray; C. K. Riley; H. G. Ritter; J. B. Roberts; O. V. Rogachevskiy; J. L. Romero; J. F. Ross; A. Roy; L. Ruan; J. Rusnak; O. Rusnakova; N. R. Sahoo; P. K. Sahu; I. Sakrejda; S. Salur; J. Sandweiss; E. Sangaline; A. Sarkar; J. Schambach; R. P. Scharenberg; A. M. Schmah; W. B. Schmidke; N. Schmitz; J. Seger; P. Seyboth; N. Shah; E. Shahaliev; P. V. Shanmuganathan; M. Shao; B. Sharma; W. Q. Shen; S. S. Shi; Q. Y. Shou; E. P. Sichtermann; R. N. Singaraju; M. J. Skoby; D. Smirnov; N. Smirnov; D. Solanki; P. Sorensen; H. M. Spinka; B. Srivastava; T. D. S. Stanislaus; J. R. Stevens; R. Stock; M. Strikhanov; B. Stringfellow; M. Sumbera; X. Sun; X. M. Sun; Y. Sun; Z. Sun; B. Surrow; D. N. Svirida; T. J. M. Symons; M. A. Szelezniak; J. Takahashi; A. H. Tang; Z. Tang; T. Tarnowsky; J. H. Thomas; A. R. Timmins; D. Tlusty; M. Tokarev; S. Trentalange; R. E. Tribble; P. Tribedy; B. A. Trzeciak; O. D. Tsai; J. Turnau; T. Ullrich; D. G. Underwood; G. Van Buren; G. van Nieuwenhuizen; M. Vandenbroucke; J. A. Vanfossen, Jr.; R. Varma; G. M. S. Vasconcelos; A. N. Vasiliev; R. Vertesi; F. Videbæk; Y. P. Viyogi; S. Vokal; A. Vossen; M. Wada; F. Wang; G. Wang; H. Wang; J. S. Wang; X. L. Wang; Y. Wang; Y. Wang; G. Webb; J. C. Webb; G. D. Westfall; H. Wieman; S. W. Wissink; R. Witt; Y. F. Wu; Z. Xiao; W. Xie; K. Xin; H. Xu; J. Xu; N. Xu; Q. H. Xu; Y. Xu; Z. Xu; W. Yan; C. Yang; Y. Yang; Y. Yang; Z. Ye; P. Yepes; L. Yi; K. Yip; I-K. Yoo; N. Yu; Y. Zawisza; H. Zbroszczyk; W. Zha; J. B. Zhang; J. L. Zhang; S. Zhang; X. P. Zhang; Y. Zhang; Z. P. Zhang; F. Zhao; J. Zhao; C. Zhong; X. Zhu; Y. H. Zhu; Y. Zoulkarneeva; M. Zyzak

2014-07-15

272

Development of magnetically separable immobilized lipase by using cellulose derivatives and their application in enantioselective esterification of ibuprofen.  

PubMed

Highly active, stable, and magnetically separable immobilized enzymes were developed using carboxymethyl cellulose (CMC) and diethylaminoethyl cellulose DEAE-C; hereafter designated "DEAE" as supporting materials. Iron oxide nanoparticles penetrated the micropores of the supporting materials, rendering them magnetically separable. Lipase (LP) was immobilized on the surface of the supporting materials by using cross-linked enzyme aggregation (CLEA) by glutaraldehyde. The activity of enzyme aggregates coated on DEAE was approximately 2 times higher than that of enzyme aggregates coated on CMC. This is explained by the fact that enzyme aggregates with amine residues are more efficient than those with carboxyl residues. After a 96-h enantioselective ibuprofen esterification reaction, 6% ibuprofen propyl ester was produced from the racemic mixture of ibuprofen by using DEAE-LP, and 2.8% using CMC-LP. PMID:18388463

Lee, Gowoun; Joo, Hongil; Kim, Jungbae; Lee, Jung-Heon

2008-03-01

273

Beam-Energy Dependence of Charge Separation along the Magnetic Field in Au +Au Collisions at RHIC  

NASA Astrophysics Data System (ADS)

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au +Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy and tends to vanish by 7.7 GeV. This implies the dominance of hadronic interactions over partonic ones at lower collision energies.

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.

2014-08-01

274

Beam-energy dependence of charge separation along the magnetic field in Au+Au collisions at RHIC.  

PubMed

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with decreased beam energy and tends to vanish by 7.7 GeV. This implies the dominance of hadronic interactions over partonic ones at lower collision energies. PMID:25126911

Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Davila Leyva, A; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Madagodagettige Don, D M M D; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Voloshin, S A; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

2014-08-01

275

Separating subspectra from cross-polarization magic-angle spinning nuclear magnetic resonance spectra by proton spin relaxation editing  

Microsoft Academic Search

Differences in proton spin relaxation time constants can be exploited to edit cross-polarization magic-angle spinning nuclear magnetic resonance (CP-MAS NMR) spectra of heterogeneous mixtures of different types of organic matter. This paper describes an extension of the editing procedure from two-component to three-component mixtures. Clean separation of 13C NMR subspectra was achieved for three synthetic polymers mixed as powders. Applying

Roger H. Newman; Leo M. Condron

1995-01-01

276

Magnetic hydroxyapatite nanoparticles: an efficient adsorbent for the separation and removal of nitrate and nitrite ions from environmental samples.  

PubMed

A novel type of magnetic nanosorbent, hydroxyapatite-coated Fe2O3 nanoparticles was synthesized and used for the adsorption and removal of nitrite and nitrate ions from environmental samples. The properties of synthesized magnetic nanoparticles were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffraction. After the adsorption process, the separation of ?-Fe2O3@hydroxyapatite nanoparticles from the aqueous solution was simply achieved by applying an external magnetic field. The effects of different variables on the adsorption efficiency were studied simultaneously using an experimental design. The variables of interest were amount of magnetic hydroxyapatite nanoparticles, sample volume, pH, stirring rate, adsorption time, and temperature. The experimental parameters were optimized using a Box-Behnken design and response surface methodology after a Plackett-Burman screening design. Under the optimum conditions, the adsorption efficiencies of magnetic hydroxyapatite nanoparticles adsorbents toward NO3(-) and NO2(-) ions (100 mg/L) were in the range of 93-101%. The results revealed that the magnetic hydroxyapatite nanoparticles adsorbent could be used as a simple, efficient, and cost-effective material for the removal of nitrate and nitrite ions from environmental water and soil samples. PMID:25376506

Ghasemi, Ensieh; Sillanpää, Mika

2015-01-01

277

Dense Plasma Focus Z-pinches for High Gradient Particle Acceleration  

SciTech Connect

The final Z-pinch stage of a Dense Plasma Focus (DPF) could be used as a simple, compact, and potentially rugged plasma-based high-gradient accelerator with fields at the 100 MV/m level. In this paper we review previously published experimental beam data that indicate the feasibility of such an DPF-based accelerator, qualitatively discuss the physical acceleration processes in terms of the induced voltages, and as a starting point examine the DPF acceleration potential by numerically applying a self-consistent DPF system model that includes the induced voltage from both macroscopic and instability driven plasma dynamics. Applications to the remote detection of high explosives and a multi-staged acceleration concept are briefly discussed.

Tang, V; Adams, M L; Rusnak, B

2009-07-24

278

An Ultra-High Gradient Cherenkov Wakefield Acceleration Experiment at SLAC FFTB  

SciTech Connect

The creation of ultra-high current, ultra-short pulse beams Q=3 nC, {sigma}{sub z} = 20{micro}m at the SLAC FFTB has opened the way for very high gradient plasma wakefield acceleration experiments. We study here the use of these beams in a proposed Cherenkov wakefield experiment, where one may excite electromagnetic wakes in a simple dielectric tube with inner diameter of few 100 microns that exceed the GV/m level. We discuss the scaling of the fields with design geometric design parameters, and choice of dielectric. We also examine measurable aspects of the experiment, such as the total coherent Cerenkov radiation energy one may collect, and the expected aspects of dielectric breakdown at high fields.

Rosenzweig, J.B.; Hoover, S.; Hogan, M.J.; Muggli, P.; Thompson, M.; Travish, G.; Yoder, R.; /UCLA /SLAC /Southern California U.

2005-08-02

279

Ultra-High Gradient Compact S-Band Linac for Laboratory and Industrial Applications  

SciTech Connect

There is growing demand from the industrial and research communities for high gradient, compact RF accelerating structures. The commonly used S-band SLAC-type structure has an operating gradient of only about 20 MV/m; while much higher operating gradients (up to 70 MV/m) have been recently achieved in X-band, as a consequence of the substantial efforts by the Next Linear Collider (NLC) collaboration to push the performance envelope of RF structures towards higher accelerating gradients. Currently however, high power X-band RF sources are not readily available for industrial applications. Therefore, RadiaBeam Technologies is developing a short, standing wave S-band structure which uses frequency scaled NLC design concepts to achieve up to a 50 MV/m operating gradient at 2856 MHz. The design and prototype commissioning plans are presented.

Faillace, Luigi; /RadiaBeam Tech.; Agustsson, Ronald; /RadiaBeam Tech.; Frigola, Pedro; /RadiaBeam Tech.; Murokh, Alex; /RadiaBeam Tech.; Dolgashev, Valery; /SLAC; Rosenzweig, James; /UCLA

2012-07-03

280

Progress of ILC High Gradient SRF Cavity R&D at Jefferson Lab  

SciTech Connect

Latest progress of ILC high gradient SRF cavity R&D at Jefferson Lab will be presented. 9 out of 10 real 9-cell cavities reached an accelerating gradient of more than 38 MV/m at a unloaded quality factor of more than 8 {center_dot} 109. New understandings of quench limitation in 9-cell cavities are obtained through instrumented studies of cavities at cryogenic temperatures. Our data have shown that present limit reached in 9-cell cavities is predominantly due to localized defects, suggesting that the fundamental material limit of niobium is not yet reached in 9-cell cavities and further gradient improvement is still possible. Some examples of quench-causing defects will be given. Possible solutions to pushing toward the fundamental limit will be described.

R.L. Geng, J. Dai, G.V. Eremeev, A.D. Palczewski

2011-09-01

281

HIGH-GRADIENT, HIGH-TRANSFORMER-RATIO, DIELECTRIC WAKE FIELD ACCELERATOR  

SciTech Connect

The Phase I work reported here responds to DoE'ss stated need "...to develop improved accelerator designs that can provide very high gradient (>200 MV/m for electrons...) acceleration of intense bunches of particles." Omega-P'�s approach to this goal is through use of a ramped train of annular electron bunches to drive a coaxial dielectric wakefield accelerator (CDWA) structure. This approach is a direct extension of the CDWA concept from acceleration in wake fields caused by a single drive bunch, to the more efficient acceleration that we predict can be realized from a tailored (or ramped) train of several drive bunches. This is possible because of a much higher transformer ratio for the latter. The CDWA structure itself has a number of unique features, including: a high accelerating gradient G, potentially with G > 1 GeV/m; continuous energy coupling from drive to test bunches without transfer structures; inherent transverse focusing forces for particles in the accelerated bunch; highly stable motion of high charge annular drive bunches; acceptable alignment tolerances for a multi-section system. What is new in the present approach is that the coaxial dielectric structure is now to be energized by-not one-�but by a short train of ramped annular-shaped drive bunches moving in the outer coaxial channel of the structure. We have shown that this allows acceleration of an electron bunch traveling along the axis in the inner channel with a markedly higher transformer ratio T than for a single drive bunch. As described in this report, the structure will be a GHz-scale prototype with cm-scale transverse dimensions that is expected to confirm principles that can be applied to the design of a future THz-scale high gradient (> 500 MV/m) accelerator with mm-scale transverse dimensions. We show here a new means to significantly increase the transformer ratio T of the device, and thereby to significantly improve its suitability as a flexible and effective component in a future high energy, high gradient accelerator facility. We predict that the T of a high gradient CDWA can be increased by a substantial factor; this enhancement is dramatically greater than what has been demonstrated heretofore. This large enhancement in T that we predict arises from using a train of three or four drive bunches in which the spacing of the bunches and their respective charges are selected according to a simple principle that requires each bunch lose energy to the wakefields at the same rate, so as not to sacrifice drive beam efficiency�¢����as would be the case if one bunch exhausted its available energy while others had not. It is anticipated that results from the study proposed here can have a direct impact on design of the dielectric accelerator in a TeV-scale collider concept, and in the accelerator for an x-ray FEL.

Jay L. Hirshfield

2012-04-12

282

Fabrication Technologies of the High Gradient Accelerator Structures at 100MV/M Range  

SciTech Connect

A CERN-SLAC-KEK collaboration on high gradient X-band structure research has been established in order to demonstrate the feasibility of the CLIC baseline design for the main linac stably operating at more than 100 MV/m loaded accelerating gradient. Several prototype CLIC structures were successfully fabricated and high power tested. They operated at 105 MV/m with a breakdown rate that meets the CLIC linear collider specifications of < 5 x 10{sup -7}/pulse/m. This paper summarizes the fabrication technologies including the mechanical design, precision machining, chemical cleaning, diffusion bonding as well as vacuum baking and all related assembly technologies. Also, the tolerances control, tuning and RF characterization will be discussed.

Wang, Juwen; /SLAC; Lewandowski, James; /SLAC; Van Pelt, John; /SLAC; Yoneda, Charles; /SLAC; Gudkov, Boris; /CERN; Riddone, Germana; /CERN; Higo, Toshiyasu; /KEK, Tsukuba; Takatomi, Toshikazu; /KEK, Tsukuba

2012-07-03

283

Ion Solid Interaction And Surface Modification At RF Breakdown In High-Gradient Linacs  

SciTech Connect

Ion solid interactions have been shown to be an important new mechanism of unipolar arc formation in high-gradient rf linear accelerators through surface self-sputtering by plasma ions, in addition to an intense surface field evaporation. We believe a non-Debye plasma is formed in close vicinity to the surface and strongly affects surface atomic migration via intense bombardment by ions, strong electric field, and high surface temperature. Scanning electron microscope studies of copper surface of an rf cavity were conducted that show craters, arc pits, and both irregular and regular ripple structures with a characteristic length of 2 microns on the surface. Strong field enhancements are characteristic of the edges, corners, and crack systems at surfaces subjected to rf breakdown.

Insepov, Zeke; Norem, Jim [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Veitzer, Seth [Tech-X Corp., 5621 Arapahoe Ave., Suite A, Boulder CO 80303 (United States)

2011-06-01

284

Characteristics of high gradient insulators for accelerator and high power flow applications  

SciTech Connect

The high gradient insulator has been demonstrated to operate at levels comparable or better than special geometry or coated insulators. Some patented insulator configurations allow for sophisticated accelerator structures, high power flow interfaces, and microwave applications not previously possible. Sophisticated manufacturing techniques available at AlliedSignal FM and T made this development possible. Bipolar and high power flow applications are specially suited for present insulator designs. The insulator shows a beneficial effect when used under RF fields or RF structures. These insulators can be designed, to a first approximation, from simple electron flight path equations. With a recently developed model of surface flashover physics the authors completed a set of design calculations that include effects such as layer density and dielectric/metal thickness. Experimental data, obtained in the last few years of development, is presented and reviewed. Several insulator fabrication characteristics, indicating critical design parameters, are also presented.

Elizondo, J.M.; Krogh, M.L.; Smith, D. [and others

1997-07-01

285

Magnetic Field Effect on Laser Isotope Separation Based on Polarization Selection Rules  

Microsoft Academic Search

Excitation dynamics of atoms by linearly polarized lasers were analyzed for J=2-->2-->1-->0 multistep transition under a magnetic field. The time evolution of the population in each magnetic substate was calculated by solving the rate equations under the condition where the atomic alignment is gradually destroyed by the precession motion of the angular momentum around the magnetic field. Isotopic selectivity in

Hideaki Niki; Iwao Kitazima; Yasukazu Izawa

1998-01-01

286

Pathogen detection in complex samples by quartz crystal microbalance sensor coupled to aptamer functionalized core-shell type magnetic separation.  

PubMed

A quartz crystal microbalance sensor (QCM) was developed for sensitive and specific detection of Salmonella enterica serovar typhimurium cells in food samples by integrating a magnetic bead purification system. Although many sensor formats based on bioaffinity agents have been developed for sensitive and specific detection of bacterial cells, the development of robust sensor applications for food samples remained a challenging issue. A viable strategy would be to integrate QCM to a pre-purification system. Here, we report a novel and sensitive high throughput strategy which combines an aptamer-based magnetic separation system for rapid enrichment of target pathogens and a QCM analysis for specific and real-time monitoring. As a proof-of-concept study, the integration of Salmonella binding aptamer immobilized magnetic beads to the aptamer-based QCM system was reported in order to develop a method for selective detection of Salmonella. Since our magnetic separation system can efficiently capture cells in a relatively short processing time (less than 10 min), feeding captured bacteria to a QCM flow cell system showed specific detection of Salmonella cells at 100 CFU mL(-1) from model food sample (i.e., milk). Subsequent treatment of the QCM crystal surface with NaOH solution regenerated the aptamer-sensor allowing each crystal to be used several times. PMID:25467500

Ozalp, Veli C; Bayramoglu, Gulay; Erdem, Zehra; Arica, M Yakup

2015-01-01

287

Two Alternate High Gradient Quadrupoles; An Upgraded Tevatron IR and A"Pipe" Design  

SciTech Connect

With the U.S. cancellation of the SSC project, the only large approved hadron accelerator project is CERN's LHC. One of the more critical elements in the performance of a collider is the quadrupole lens at the beam collision points. These quadrupoles, usually referred to as the 'insertion quads' normally form a set of triplets around the interaction region. Their focal power directly affects the luminosity available at the crossing point In order to achieve as high a gradient as possible, the CERN design team has proposed a very efficient high gradient quadrupole which is based on a graded four-layer winding structure. At Fermilab's Tevatron, an upgraded two layer winding quadrupole has been in operation since 1989, and has provided a 50% higher gradient than its predecessor. The quadrupole was basically state of the art when it was designed in 1985. Since then however, improvements have been made in cabling, conductor perfonnance, etc. Naturally, operation of a modernized version of this .design can provide higher capabilities. This improved two layer design can serve as an alternative to the more intricate graded four layer design now envisioned for the LHC, provided it can obtain the proposed gradient. A high gradient quadrupole with a 'pipe' layout can be considered as a possible candidate for future large collider insertion regions. It is possible to fine-tune the design to obtain a good field-quality, the conductor is well cooled in case of a large radiation heat load, and the overall structure is smaller than a conventional quadrupole with a comparable field gradient.

McInturff, A.D.; Oort, J.M. van; Scanlan, R.M.

1995-04-01

288

Orthorhombic distortion and novel magnetic phase separation in Pr0.5Eu0.5MnO3  

NASA Astrophysics Data System (ADS)

Structural and magnetic measurements were done on polycrystalline manganite, Pr0.5 Eu0.5 MnO3. The Rietveld refinement of the x-ray powder diffraction pattern at room temperature suggests considerable Jahn-Teller distortion due to ionic size mismatch of the isovalent ions. Dc and ac magnetometry suggest a disordered antiferromagnetic (AFM) state, exhibiting glassy magnetic behavior at low temperature. Cooling in a static magnetic field reveals a considerable shift of the magnetic hysteresis loops, a typical manifestation of exchange bias. Interestingly, we observe the absence of training effect in exchange bias. The temperature, cooling field dependent study of exchange bias, and absence of exchange bias in La0.5 Eu0.5 MnO3 suggest a novel low temperature phase separation between a disordered AFM phase induced by the Mn moments and another highly anisotropic phase involving ordering related to the rare-earth moments. It appears that this unique magnetic ground state exhibiting exchange bias is a consequence of the structural distortion inherent in the system.

Karmakar, A.; Majumdar, S.; Giri, S.

2011-09-01

289

Capture and separation of biomolecules using magnetic beads in a simple microfluidic channel without an external flow device.  

PubMed

The use of microfluidic devices and magnetic beads for applications in biotechnology has been extensively explored over the past decade. Many elaborate microfluidic chips have been used in efficient systems for biological assays. However most fail to achieve the ideal point of care (POC) status, as they require larger conventional external devices in conjunction with the microchip. This paper presents a simple technique to capture and separate biomolecules using magnetic bead movement on a microchip without the use of an external flow device. This microchip consisted of two well reservoirs (W1 and W2) connected via a tapered microchannel. Beads were dragged through the microchannel between the two wells at an equivalent speed to a permanent magnet that moved alongside the microchip. More than 95% of beads were transferred from W1 to W2 within 2 min at an average velocity of 0.7 mm s(-1). Enzymatic reactions were employed to test our microchip. Specifically, three assays were performed using the streptavidin coated magnetic beads as a solid support to capture and transfer biomolecules: (1) non-specific adsorption of the substrate, 6-8-difluoro-4-methylumbelliferyl phosphate (DiFMUP), (2) capture of the enzyme, biotinylated alkaline phosphatase (AP), and (3) separation of AP from DiFMUP. Our non-specific adsorption assay indicated that the microchip was capable of transferring the beads with less than 0.002% carryover of DiFMUP. Our capture assay indicated efficient capture and transfer of AP with beads to W2 containing DiFMUP, where the transferred AP converted 100% of DiFMUP to DiFMU within 15 minutes. Our separation assay showed effective separation of AP from DiFMUP and elucidated the binding capacity of the beads for AP. The leftover unbound AP in W1 converted 100% of DiFMUP within 10 minutes and samples with less than the full bead capacity of AP (i.e. all AP was transferred) did not convert any of the DiFMUP. The immobilization of AP on the bead surface resulted in 32% reduced enzymatic speed compared to that of free AP in solution, as a result of altered protein conformation and/or steric hindrance of the catalytic site. Overall, this microfluidic platform was established as a simple, efficient and effective approach for separating biomolecules without any flow apparatus. PMID:24051541

Wang, Jingjing; Morabito, Kenneth; Erkers, Tom; Tripathi, Anubhav

2013-11-01

290

Development of magnetic separation and quantum dots labeled immunoassay for the detection of mercury in biological samples.  

PubMed

A rapid and sensitive immunoassays of mercury (Hg) in biological samples was developed using quantum dots (QDs) and magnetic beads (MBs) as fluorescent and separated probes, respectively. A monoclonal antibody (mAb) that recognizes an Hg detection antigen (BSA-DTPA-Hg) complex was produced by the injection of BALB/c mice with an Hg immunizing antigen (KLH-DTPA-Hg). Then the ascites monoclonal antibodies were purified. The Hg monoclonal antibody (Hg-mAb) is conjugated with MBs to separate Hg from biological samples, and the other antibody, which is associated with QDs, is used to detect the fluorescence. The Hg in biological samples can be quantified using the relationship between the QDs fluorescence intensity and the concentration of Hg in biological samples following magnetic separation. In this method, the detection linear range is 1-1000ng/mL, and the minimum detection limit is 1ng/mL. The standard addition recovery rate was 94.70-101.18%. The relative standard deviation values were 2.76-7.56%. Furthermore, the Hg concentration can be detected in less than 30min, the significant interference of other heavy metals can be avoided, and the simultaneous testing of 96 samples can be performed. These results indicate that the method could be used for rapid monitoring Hg in the body. PMID:25744508

Sun, Hubo; Wang, Mengmeng; Wang, Jilong; Tian, Mi; Wang, Hui; Sun, Zhiwei; Huang, Peili

2015-04-01

291

Application of magnetic poly(styrene-glycidyl methacrylate) microspheres for immunomagnetic separation of bone marrow cells  

NASA Astrophysics Data System (ADS)

Surface-functionalized magnetic poly(styrene-glycidyl methacrylate) (PS-GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1 + cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1 + cells corresponding to a 17-fold enrichment was achieved.

Chung, Ting-Hao; Chang, Jing-Yi; Lee, Wen-Chien

2009-05-01

292

Protein separation and identification using magnetic beads encoded with surface-enhanced Raman spectroscopy  

Microsoft Academic Search

This article presents a prototype of a surface-enhanced Raman spectroscopy (SERS)-encoded magnetic bead of 8?m diameter. The core part of the bead is composed of a magnetic nanoparticle (NP)-embedded sulfonated polystyrene bead. The outer part of the bead is embedded with Ag NPs on which labeling molecules generating specific SERS bands are adsorbed. A silica shell is fabricated for further

Bong-Hyun Jun; Mi Suk Noh; Gunsung Kim; Homan Kang; Jong-Ho Kim; Woo-Jae Chung; Min-Soo Kim; Yong-Kweon Kim; Myung-Haing Cho; Dae Hong Jeong; Yoon-Sik Lee

2009-01-01

293

New high performance hybrid magnet plates for DNA separation andbio-technology applications  

SciTech Connect

A new class of magnet plates for biological and industrial applications has recently been developed at the D.O.E. Joint Genome Institute and Lawrence Berkeley National Laboratory (JGI/LBNL). These devices utilize hybrid technology that combines linear permanent magnet material and ferromagnetic material to produce significantly higher fields and gradients than currently available commercial magnet plates. These hybrid structures incorporate ferromagnetic poles that can be easily shaped to produce complex field distributions for specialized applications. The higher maximum fields and strong gradients of the hybrid structures result in greater holding forces on magnetized targets that are being processed as well as faster draw-down. Current development versions of these magnet plates have exhibited maximum fields in excess of 9000.0 Gauss. The design of these structures is easily scalable to allow for field increases to significantly above 1.0 tesla (10000.0gauss). Author's note: 11000.0 Gauss peak fields have been achieved as of January 2005.

Humphries, David; Pollard, Martin; Elkin, Chris; Petermann, Karl; Reiter, Charles; Cepeda, Mario

2004-08-02

294

Separation of circumferential magnetic components from MI spectra in laser-annealed Co-based amorphous microwires  

Microsoft Academic Search

A commercial glass-covered Co-based amorphous microwire (Co66Fe3.8Ni1.4B11.5Si14.6Mo1.7) with metallic core diameter of 17 ?m was annealed in air by illuminating the pulsed Nd:YAG laser beams under longitudinal and transverse annealing fields, denoted by Hl and Ht, respectively. The static susceptibilities by domain-wall motion and magnetization rotation, ?dw and ?rot, were separated from the circumferential complex permeability extracted from impedance spectra.

S. S. Yoon; B. S. Lee; Y. W. Rheem; S. J. Ahn; C. G. Kim; C. O. Kim

2003-01-01

295

Rapid purification and characterization of angiotensin converting enzyme inhibitory peptides from lizard fish protein hydrolysates with magnetic affinity separation.  

PubMed

In this study, angiotensin converting enzyme (ACE) inhibitory peptides from lizard fish protein hydrolysate with neutral protease were purified through magnetic affinity separation. Magnetic agarose microsphere was prepared by reverse-phase microemulsion method, and its surface was modified with epoxy groups to immobilize ACE as a magnetic affinity medium (MAM-ACE) and then mixed with lizard fish ultrafiltration hydrolysate (<5kDa). The MAM-ACE was recovered by a magnet. The bound peptides were released by 1M NaCl and further purified by reverse-phase high-performance liquid chromatography. The amino acid sequence of the peptide with the highest ACE inhibitory activity was identified as Gly-Met-Lys-Cys-Ala-Phe, and its IC50 was 45.7±1.1?M. The result indicates that MAM-ACE is a faster and more efficient method for purifying micro-bioactive peptides from food protein complex mixtures compared with ion exchange and gel chromatography. PMID:25842319

Lan, Xiongdiao; Liao, Dankui; Wu, Shanguang; Wang, Feng; Sun, Jianhua; Tong, Zhangfa

2015-09-01

296

Separation and enrichment of six indicator polychlorinated biphenyls from real waters using a novel magnetic multiwalled carbon nanotube composite absorbent.  

PubMed

A novel and effective magnetic multiwalled carbon nanotube composite for the separation and enrichment of polychlorinated biphenyls was developed. Fe3 O4 @SiO2 core-shell structured nanoparticles were first synthesized, then the poly(sodium 4-styrenesulfonate) was laid on its surface to prepare the polyanionic magnetic nanoparticles. The above materials were then grafted with polycationic multiwalled carbon nanotubes, which were modified by polydiallyl dimethyl ammonium chloride through the layer-by-layer self-assembly approach. Its performance was tested by magnetic solid-phase extraction and gas chromatography with mass spectrometry for the determination of six kinds of indicator polychlorinated biphenyls in water samples. Under optimal conditions, the spiked recoveries of several real samples for six kinds of polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB138, PCB153, PCB180) were in the range of 73.4-99.5% with relative standard deviations varying from 1.5 to 8.4%. All target compounds showed good linearities in the tested range with correlation coefficients higher than 0.9993. The limits of quantification for six kinds of indicator polychlorinated biphenyls were between 0.018 and 0.039 ng/mL. The proposed method was successfully applied to analyze polychlorinated biphenyls in real water samples. Satisfactory results were obtained using the effective magnetic absorbent. PMID:25556922

Zhang, Jiabin; Gan, Ning; Pan, Muyun; Lin, Saichai; Cao, Yuting; Wu, Dazhen; Long, Nengbing

2015-03-01

297

The UCLA/SLAC Ultra-High Gradient Cerenkov Wakefield Accelerator Experiment  

SciTech Connect

An experiment is planned to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range. This new UCLA/SLAC/USC collaboration will take advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {delta}{sub z} = 20 {micro}m at Q = 3 nC). The electron beam will be focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam will be varied in order to alter the accelerating gradient and probe the breakdown threshold of the dielectric structures. In addition to breakdown studies, we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain information about the strength of the accelerating fields.

Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; /UCLA; Hogan, M.; Ischebec, R.; Siemann, R.; Walz, D.; /SLAC; Scott, A.; /UC, Santa Barbara; Yoder, R.; /Manhattan Coll., Riverdale

2006-01-25

298

Preliminary Results from the UCLA/SLAC Ultra-High Gradient CerenkovWakefield Accelerator Experiment  

SciTech Connect

The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. This experiment takes advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam has been successfully focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam was varied in the range 20 {micro}m < {sigma}{sub z} < 100 {micro}m which produced a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain more information about the strength of the accelerating fields.

Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; /UCLA; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Muggli, P.; /Southern California U.; Scott, A.; /UC, Santa Barbara; Yoder, R.; /Manhattan Coll., Riverdale

2008-02-06

299

Summary report of Working Group 3: Laser and high-gradient structure-based acceleration  

NASA Astrophysics Data System (ADS)

Working Group (WG) 3 assessed current challenges in developing advanced accelerators based on RF and laser-driven electromagnetic (EM) structures and surveyed the state-of-the-art research and methods addressing these challenges. A critical challenge for EM structures is the gradient limitation imposed by RF breakdown, pulsed heating, dark current, quench, thermal breakdown and other factors, depending on structure type, pulse width, duty cycle and regime of operation. Other challenges include developing approaches to reduce cost and size while at the same time greatly increasing performance. WG 3 examined a variety of approaches to the improve gradient, cost, size, and performance of advanced accelerators including dielectric loaded structures, photonic bandgap structures, solid-state crystal structures, terahertz generation technologies, inverse FELs and undulators, micro-accelerators and light sources, high gradient structures, and RF sources. These approaches cover a large range of frequencies and span a considerable parameter space including room temperature and superconducting devices, THz and optical EM, and dielectric-based structures. The state of the art was surveyed in RF source and component development, materials development, advanced micro-and nano-fabrication technologies, and surface coatings for accelerator applications. WG 3 also attempted to address challenges beyond gradient limitation, including simulation challenges, high order mode characterization, measurement, and damping, field distributions producing low emittance, power efficiency, and impact of fabrication tolerances.

Fazio, Michael V.; Anderson, Scott G.

2012-12-01

300

High Gradient Performance of NLC/GLC X-band Accelerating Structures  

SciTech Connect

During the past five years, there has been a concerted program at SLAC and KEK to develop accelerator structures that meet the high gradient (65 MV/m) performance requirements for the Next Linear Collider (NLC) and Global Linear Collider (GLC) initiatives. The design that resulted is a 60-cm-long, traveling-wave structure with low group velocity and 150 degree per cell phase advance. It has an average iris size that produces an acceptable short-range wakefield, and dipole mode damping and detuning that adequately suppresses the long-range wakefield. More than eight such structures have operated at a 60 Hz repetition rate over 1000 hours at 65 MV/m with 400 ns long pulses, and have reached breakdown rate levels below the limit for the linear collider. Moreover, the structures are robust in that the rates continue to decrease over time, and if the structures are briefly exposed to air, the rates recover to their low levels within a few days. This paper presents a summary of the results from this program, which effectively ended last August with the selection of ''cold'' technology for an International Linear Collider (ILC).

Doebert, S.; Adolphsen, C.; Bowden, G.; Burke, D.; Chan, J.; Dolgashev, V.; Frisch, J.; Jobe, K.; Jones, R.; Lewandowski, J.; Kirby, R.; Li, Z.; McCormick, D.; Miller,; Nantista, C.; Nelson, J.; Pearson, C.; Ross, M.; Schultz, D.; Smith, T.; Tantawi, S.; /SLAC /Fermilab /KEK, Tsukuba

2005-05-17

301

Intense electron emission due to picosecond laser-produced plasmas in high gradient electric fields  

SciTech Connect

Picosecond laser pulses at a wavelength of 266 nm have been focused onto a solid metal cathode in coincidence with high gradient electric fields to produce high brightness electron beams. At power densities exceeding 10{sup 9} W/cm{sup 2}, a solid density plasma is formed and intense bursts of electrons are emitted from the target accompanied by macroscopic surface damage. An inferred {similar to}1 {mu}C of integrated charge with an average current of {similar to}20 A is emitted from a radio-frequency cavity driven at electric field gradients of {similar to}80 MV/m. In another experiment, where a dc extraction field of {similar to}6 MV/m is used, we observed an electron charge of {similar to}0.17 {mu}C. Both results are compared with the Schottky effect and the Fowler--Nordheim field emission. We found that this laser-induced intense electron emission shares many features with the explosive electron emission processes. No selective wavelength dependence is observed in the production of the intense electron emission in the dc extraction field. The integrated electrons give an apparent quantum efficiency of {similar to}1.2%, which is one of the highest reported to date from metal photocathodes at these photon energies.

Wang, X.J.; Tsang, T.; Kirk, H.; Srinivasan-Rao, T.; Fischer, J.; Batchelor, K.; Russell, P.; Fernow, R.C. (Brookhaven National Laboratory, Upton, New York 11973 (United States))

1992-08-01

302

High gradient tests of an 88 MHz RF cavity for muon cooling  

E-print Network

The scheme for a Muon Cooling channel developed at CERN in the frame of Neutrino Factory studies foresees the use of 44 and 88 MHz cavities operating at a real-estate gradient as high as 4 MV/m. To assess the feasibility of this scheme, including high-gradient operation at relatively low frequency and the production and handling of high RF peak powers, a test stand was assembled at CERN. It included an 88 MHz resonator reconstructed from a 114 MHz cavity previously used for lepton acceleration in the PS, a 2.5 MW final amplifier made out of an old linac unit improved and down-scaled in frequency, and a PS spare amplifier used as driver stage. After only 160 hours of conditioning the cavity passed the 4 MV/m level, with local peak surface field in the gap exceeding 25 MV/m (2.4 times the Kilpatrick limit). The gradient was limited by the amplifier power, the maximum RF peak output power achieved during the tests being 2.65 MW. This paper presents the results of the tests, including an analysis of field emissio...

Rossi, C; Gerigk, F; Marques-Balula, J; Vretenar, M

2006-01-01

303

FABRICATION AND INITIAL TESTS OF AN ULTRA-HIGH GRADIENT COMPACT S-BAND (HGS) ACCELERATING STRUCTURE*  

E-print Network

of industrially available high peak power RF sources in X-band and beyond. The development of the HGS structure research was performed under the NLC program to demonstrate successful high gradient operation of X-band of the mature and commercially available S-band high power klystron technology. RF DESIGN The RF design

Brookhaven National Laboratory

304

Microcystin-LR removal from aqueous solutions using a magnetically separable N-doped TiO2 nanocomposite under visible light irradiation  

EPA Science Inventory

The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with a non-magnetic N-doped TiO2 for the aqueous removal of cyanotoxin Microcystin-LR. The observed enhanced photocatalytic activity may be related to the presence of ferri...

305

Multifunctional superparamagnetic nanoshells: combining two-photon luminescence imaging, surface-enhanced Raman scattering and magnetic separation  

NASA Astrophysics Data System (ADS)

With the increasing need for multi-purpose analysis in the biomedical field, traditional single diagnosis methods cannot meet the requirements. Therefore new multifunctional technologies and materials for the integration of sample collection, sensing and imaging are in great demand. Core-shell nanoparticles offer a unique platform to combine multifunctions in a single particle. In this work, we have constructed a novel type of core-shell superparamagnetic nanoshell (Fe3O4@SiO2@Au), composed of a Fe3O4 cluster core, a thin Au shell and a SiO2 layer in between. The obtained multifunctional nanoparticles combine the magnetic properties and plasmonic optical properties effectively, which were well investigated by a number of experimental characterization methods and theoretical simulations. We have demonstrated that Fe3O4@SiO2@Au nanoparticles can be utilized for two-photon luminescence (TPL) imaging, near-infrared surface-enhanced Raman scattering (NIR SERS) and cell collection by magnetic separation. The TPL intensity could be further greatly enhanced through the plasmon coupling effect in the self-assembled nanoparticle chains, which were triggered by an external magnetic field. In addition, Fe3O4@SiO2@Au nanoparticles may have great potential applications such as enhanced magnetic resonance imaging (MRI) and photo-thermotherapy. Successful combination of multifunctions including magnetic response, biosensing and bioimaging in single nanoparticles allows further manipulation, real-time tracking, and intracellular molecule analysis of live cells at a single-cell level.With the increasing need for multi-purpose analysis in the biomedical field, traditional single diagnosis methods cannot meet the requirements. Therefore new multifunctional technologies and materials for the integration of sample collection, sensing and imaging are in great demand. Core-shell nanoparticles offer a unique platform to combine multifunctions in a single particle. In this work, we have constructed a novel type of core-shell superparamagnetic nanoshell (Fe3O4@SiO2@Au), composed of a Fe3O4 cluster core, a thin Au shell and a SiO2 layer in between. The obtained multifunctional nanoparticles combine the magnetic properties and plasmonic optical properties effectively, which were well investigated by a number of experimental characterization methods and theoretical simulations. We have demonstrated that Fe3O4@SiO2@Au nanoparticles can be utilized for two-photon luminescence (TPL) imaging, near-infrared surface-enhanced Raman scattering (NIR SERS) and cell collection by magnetic separation. The TPL intensity could be further greatly enhanced through the plasmon coupling effect in the self-assembled nanoparticle chains, which were triggered by an external magnetic field. In addition, Fe3O4@SiO2@Au nanoparticles may have great potential applications such as enhanced magnetic resonance imaging (MRI) and photo-thermotherapy. Successful combination of multifunctions including magnetic response, biosensing and bioimaging in single nanoparticles allows further manipulation, real-time tracking, and intracellular molecule analysis of live cells at a single-cell level. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04111a

Jin, Xiulong; Li, Haiyan; Wang, Shanshan; Kong, Ni; Xu, Hong; Fu, Qihua; Gu, Hongchen; Ye, Jian

2014-11-01

306

Development of an aptamer-based impedimetric bioassay using microfluidic system and magnetic separation for protein detection.  

PubMed

An aptamer-based impedimetric bioassay using the microfluidic system and magnetic separation was developed for the sensitive and rapid detection of protein. The microfluidic impedance device was fabricated through integrating the gold interdigitated array microelectrode into a flow cell made of polydimethylsiloxane (PDMS). Aptamer modified magnetic beads were used to capture and separate the target protein, and concentrated into a suitable volume. Then the complexes were injected into the microfluidic flow cell for impedance measurement. To demonstrate the high performance of this novel detection system, thrombin was employed as the target protein. The results showed that the impedance signals at the frequency of 90 kHz have a good linearity with the concentrations of thrombin in a range from 0.1 nM to 10nM and the detection limit is 0.01 nM. Compared with the reported impedimetric aptasensors for thrombin detection, this method possesses several advantages, such as the increasing sensitivity, improving reproducibility, reducing sample volume and assay time. All these demonstrate the proposed detection system is an alternative way to enable sensitive, rapid and specific detection of protein. PMID:24709326

Wang, Yixian; Ye, Zunzhong; Ping, Jianfeng; Jing, Shunru; Ying, Yibin

2014-09-15

307

Well-defined nanostructured surface-imprinted polymers for highly selective magnetic separation of fluoroquinolones in human urine.  

PubMed

The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core-shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8-8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems. PMID:24853973

He, Yonghuan; Huang, Yanyan; Jin, Yulong; Liu, Xiangjun; Liu, Guoquan; Zhao, Rui

2014-06-25

308

Separating surface magnetic effects in sunspot seismology: new time-distance helioseismic diagnostics  

E-print Network

Time-distance helioseismic measurements in surface- and deep-focus geometries for wave-paths that distinguish surface magnetic contributions from those due to deeper perturbations beneath a large sunspot are presented and analysed. Travel times showing an increased wave speed region extending down to about 18 Mm beneath the spot are detected in deep-focus geometry that largely avoids use of wave field within the spot. Direction (in- or out-going wave) and surface magnetic field (or focus depth) dependent changes in frequency dependence of travel times are shown and identified to be signatures of wave absorption and conversion in near surface layers rather than that of shallowness of sunspot induced perturbations.

S. P. Rajaguru

2008-02-20

309

Synthetic ligand-coated magnetic nanoparticles for microfluidic bacterial separation from blood.  

PubMed

Bacterial sepsis is a serious clinical condition that can lead to multiple organ dysfunction and death despite timely treatment with antibiotics and fluid resuscitation. We have developed an approach to clearing bacteria and endotoxin from the bloodstream, using magnetic nanoparticles (MNPs) modified with bis-Zn-DPA, a synthetic ligand that binds to both Gram-positive and Gram-negative bacteria. Magnetic microfluidic devices were used to remove MNPs bound to Escherichia coli , a Gram-negative bacterium commonly implicated in bacterial sepsis, from bovine whole blood at flows as high as 60 mL/h, resulting in almost 100% clearance. Such devices could be adapted to clear bacteria from septicemic patients. PMID:23367876

Lee, Jung-Jae; Jeong, Kyung Jae; Hashimoto, Michinao; Kwon, Albert H; Rwei, Alina; Shankarappa, Sahadev A; Tsui, Jonathan H; Kohane, Daniel S

2014-01-01

310

CALCULATING SEPARATE MAGNETIC FREE ENERGY ESTIMATES FOR ACTIVE REGIONS PRODUCING MULTIPLE FLARES: NOAA AR11158  

SciTech Connect

It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) captured the entire emergence of NOAA AR 11158. This region emerged as two distinct bipoles, possibly connected underneath the photosphere, yet characterized by different photospheric field evolutions and fluxes. The combined active region complex produced 15 GOES C-class, two M-class, and the X2.2 Valentine's Day Flare during the four days after initial emergence on 2011 February 12. The M and X class flares are of particular interest because they are nonhomologous, involving different subregions of the active region. We use a Magnetic Charge Topology together with the Minimum Current Corona model of the coronal field to model field evolution of the complex. Combining this with observations of flare ribbons in the 1600 A channel of the Atmospheric Imaging Assembly on board SDO, we propose a minimization algorithm for estimating the amount of reconnected flux and resulting drop in magnetic free energy during a flare. For the M6.6, M2.2, and X2.2 flares, we find a flux exchange of 4.2 Multiplication-Sign 10{sup 20} Mx, 2.0 Multiplication-Sign 10{sup 20} Mx, and 21.0 Multiplication-Sign 10{sup 20} Mx, respectively, resulting in free energy drops of 3.89 Multiplication-Sign 10{sup 30} erg, 2.62 Multiplication-Sign 10{sup 30} erg, and 1.68 Multiplication-Sign 10{sup 32} erg.

Tarr, Lucas; Longcope, Dana; Millhouse, Margaret [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

2013-06-10

311

Macroinvertebrate community responses to gravel augmentation in a high-gradient, Southeastern regulated river  

SciTech Connect

Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential to evaluate the biotic response to restoration projects in order to improve the efficacy of future applications. The purpose of our study was to evaluate the response of the macroinvertebrate community to gravel addition in a high-gradient, regulated river in western North Carolina. We collected benthic macroinvertebrate samples from gravel-enhanced areas and unenhanced areas for 1 season before gravel addition, and for 4 seasons afterwards. Repeated measures multivariate analysis of variance indicated that the responses of macroinvertebrates to gravel addition were generally specific to individual taxa or particular functional feeding groups and did not lead to consistent patterns in overall family richness, diversity, density, or evenness. Non-metric multi-dimensional scaling showed that shifts in macroinvertebrate community composition were temporary and dependent upon site conditions and season. Correlations between macroinvertebrate response variables and substrate microhabitat variables existed with or without the inclusion of data from enhanced areas, which suggests that substrate-biotic relationships were present before gravel addition. A review of the current literature suggests that the responses of benthic macroinvertebrates to substrate restoration are inconsistent and dependent upon site conditions and the degree habitat improvement of pre-restoration site conditions.

McManamay, Ryan A [ORNL; Orth, Dr. Donald J [Virginia Polytechnic Institute and State University; Dolloff, Dr. Charles A [United States Department of Agriculture (USDA), United States Forest Service (USFS) and Virginia Pol

2013-01-01

312

Calculating Separate Magnetic Free Energy Estimates for Active Regions Producing Multiple Flares: NOAA AR11158  

E-print Network

It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The \\emph{Helioseismic and Magnetic Imager} (HMI) onboard the \\emph{Solar Dynamics Observatory} (SDO) captured the entire emergence of NOAA AR 11158. This region emerged as two distinct bipoles, possibly connected underneath the photosphere, yet characterized by different photospheric field evolutions and fluxes. The combined active region complex produced 15 GOES C--class, 2 M--class, and the X2.2 Valentine's Day Flare during the four days after initial emergence on February 12th, 2011. The M and X class flares are of particular interest because they are nonhomologous, involving different subregions of the active region. We use a Magnetic Charge Topology together with the Minimum Current Corona model of the coronal field to model field evolution of the complex. Combining this with observations of flare ribbons in the 1600\\AA\\ chann...

Tarr, Lucas A; Millhouse, Margaret

2013-01-01

313

Dual-responsive magnetic core-shell nanoparticles for nonviral gene delivery and cell separation.  

PubMed

We present the synthesis of dual-responsive (pH and temperature) magnetic core-shell nanoparticles utilizing the grafting-from approach. First, oleic acid stabilized superparamagnetic maghemite (?-Fe(2)O(3)) nanoparticles (NPs), prepared by thermal decomposition of iron pentacarbonyl, were surface-functionalized with ATRP initiating sites bearing a dopamine anchor group via ligand exchange. Subsequently, 2-(dimethylamino)ethyl methacrylate (DMAEMA) was polymerized from the surface by ATRP, yielding dual-responsive magnetic core-shell NPs (?-Fe(2)O(3)@PDMAEMA). The attachment of the dopamine anchor group on the nanoparticle's surface is shown to be reversible to a certain extent, resulting in a grafting density of 0.15 chains per nm(2) after purification. Nevertheless, the grafted NPs show excellent long-term stability in water over a wide pH range and exhibit a pH- and temperature-dependent reversible agglomeration, as revealed by turbidimetry. The efficiency of ?-Fe(2)O(3)@PDMAEMA hybrid nanoparticles as a potential transfection agent was explored under standard conditions in CHO-K1 cells. Remarkably, ?-Fe(2)O(3)@PDMAEMA led to a 2-fold increase in the transfection efficiency without increasing the cytotoxicity, as compared to polyethyleneimine (PEI), and yielded on average more than 50% transfected cells. Moreover, after transfection with the hybrid nanoparticles, the cells acquired magnetic properties that could be used for selective isolation of transfected cells. PMID:22296556

Majewski, Alexander P; Schallon, Anja; Jérôme, Valérie; Freitag, Ruth; Müller, Axel H E; Schmalz, Holger

2012-03-12

314

Magnetic force control technique in industrial application  

NASA Astrophysics Data System (ADS)

Techniques of the magnetic force control have been examined for industrial application. The problems and the technique are different in dispersion medium of gas and that of liquid. In addition, the method is different depending on the magnetic characteristic of the target objects. In case of the liquid, the dispersion medium having different viscosity was examined. The separation speed is decided with the magnitude of the magnetic force because a drag force increases with the viscosity. When the water is the dispersion medium, magnetic seeding is possible and hence the nonmagnetic materials can be separated and even the dissolved material could be separated. The separation technique has been used for purifying the waste water form paper mill or wash water of drum. On the other hand when the water is not dispersion medium, mainly the ferromagnetism particle becomes the target object because the magnetic seeding becomes difficult. The iron fragments have been separated from the slurry of slicing machine of solar battery. It has been clarified high gradient magnetic separation (HGMS) can be applied for the viscous fluid of which viscosity was as high as 10 Pa s. When the dispersion medium is gaseous material, the air is important. The drag force from air depends greatly on Reynolds number. When speed of the air is small, the Reynolds number is small, and the drag force is calculated by the Stokes’ law of resistance. The study with gaseous dispersion medium is not carried out much. The magnetic separation will discuss the possibility of the industrial application of this technique.

Nishijima, S.

2010-11-01

315

Greek "red mud" residue: a study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process.  

PubMed

The present research work is focused on the development of an alternative microwave reductive roasting process of red mud using lignite (30.15 wt.%Cfix), followed by wet magnetic separation, in order to produce a raw material suitable for sponge or cast iron production. The reduction degree of iron was controlled by both the reductive agent content and the microwave heating time. The reduction followed the Fe?O? ? Fe?O? ? FeO ? Fe sequence. The dielectric constants [real (?') and imaginary (??) permittivities] of red mud-lignite mixture were determined at 2.45 GHz, in the temperature range of 25-1100 °C. The effect of parameters such as temperature, intensity of reducing conditions, intensity of magnetic field and dispersing agent addition rate on the result of both processes was investigated. The phase's transformations in reduction process with microwave heating were determined by X-ray diffraction analysis (XRD) in combination with thermogravimetric/differential thermal analysis (TGA/DTA). The microstructural and morphological characterization of the produced calcines was carried out by scanning electron microscopy (SEM). At the optimum conditions a magnetic concentrate with total iron concentration of 35.15 and 69.3 wt.% metallization degree was obtained. PMID:23611801

Samouhos, Michail; Taxiarchou, Maria; Tsakiridis, Petros E; Potiriadis, Konstantinos

2013-06-15

316

Field-flow fractionation of nucleic acids and proteins under large-scale gradient magnetic fields  

NASA Astrophysics Data System (ADS)

For the purpose of developing techniques for separating biological macromolecules, the present study reports a magnetic chromatography system employing high performance liquid chromatography and superconducting magnets of 14 and 5T. We observed chromatograms of catalase and albumin, which were eluded from columns that were exposed to magnetic fields of up to 14T with a maximum gradient of 90T/m. Without the magnetic fields, the chromatograms of the macromolecules showed a clear peak, while the chromatograms changed to have separated peaks for the same molecules after exposure to gradient magnetic fields. When the chromatocolumn was placed so the magnetic forces were opposite to the direction of flow, the albumin molecules separated into two groups. In addition, the chromatograms of catalase exposed to the magnetic fields indicated that the retention times of the two kinds of magnetically separated catalase were relatively changed if the column-field configuration was changed. Probably, the balance of paramagnetism in the heme and diamagnetism in the protein controlled the transport velocity under the influence of the gradient magnetic fields. In addition, the transport velocity of DNA molecules in the flow with a high gradient magnetic field was observed using a time-resolved spectrophotometric system.

Iwasaka, M.

2007-05-01

317

Preparation of quantum dot-coated magnetic polystyrene nanospheres for cancer cell labelling and separation  

Microsoft Academic Search

CdTe-coated magnetic polystyrene nanospheres (MPN) were prepared via a stepwise electrostatic self-assembly approach, and the conjugation of epidermal growth factor (EGF) to the MPN\\/CdTe core-shell nanocomposites was prepared by using 1-ethyl-3(3-dimethylamino propyl)-carbodiimide (EDC) as a cross-linking reagent. The MPN\\/CdTe and their bioconjugates yielded not only emitted bright fluorescence, but also exhibited superparamagnetism. The human breast cancer MDA-MB-435S cells could be

Maoquan Chu; Xin Song; Duo Cheng; Shupeng Liu; Jian Zhu

2006-01-01

318

Improvement of the separation of tumour cells from peripheral blood cells using magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Circulating tumour cells are a key challenge in tumour therapy. Numerous approaches are on the way to achieving the elimination of these potential sources of metastasis formation. Antibody-directed magnetic cell sorting is supposed to enrich tumour cells with high selectivity, but low efficiency. The short term application of carboxymethyl dextran (CMD) coated magnetit/maghemit nanoparticles allows the discrimination of tumour cells from leukocytes. In the present work we show that the interaction of CMD nanoparticles is cell-type specific and time dependent. The breast cancer cell line MCF-7 and the CML cell line K-562 are characterized by a rapid and high interaction rate, whereas leukocytes exhibit a decelerated behaviour. The addition of carboxymethyl dextran or glucose stimulated the magnetic labelling of leukocytes. The variation of the degree of substitution of dextran with carboxymethyl groups did not affect the labelling profile of leukocytes and MCF-7 cells. In order to verify the in vitro results, whole blood samples from 13 cancer patients were analysed ex vivo. Incubation of the purified leukocyte fraction with CMD nanoparticles in the presence of low amounts of plasma reduced the overall cell content in the positive fraction. In contrast, the absolute number of residual tumour cells in the positive fraction was 90% of the initial amount.

Schwalbe, M.; Pachmann, K.; Höffken, K.; Clement, J. H.

2006-09-01

319

Transmitted light relaxation and microstructure evolution of ferrofluids under gradient magnetic fields  

NASA Astrophysics Data System (ADS)

Using light transmission experiments and optical microscope observations with a longitudinal gradient magnetic field configuration, the relationship between the behavior of the transmitted light relaxation and the microstructure evolution of ionic ferrofluids in the central region of an axisymmetric field is investigated. Under a low-gradient magnetic field, there are two types of relaxation process. When a field is applied, the transmitted light intensity decreases to a minimum within a time on the order of 101-102 s. It is then gradually restored, approaching its initial value within a time on the order of 102 s. This is type I relaxation, which corresponds to the formation of magnetic columns. After the transmission reaches this value, it either increases or decreases slowly, stabilizing within a time on the order of 103 s, according to the direction of the field gradient. This is a type II relaxation, which results from the shadowing effect, corresponding to the motion of the magnetic columns under the application of a gradient force. Under a magnetic field with a centripetal high-gradient (magnetic materials subjected to a force pointing toward the center of the axisymmetric field), the transmitted light intensity decreases monotonously and more slowly than that under a low-gradient field. Magnetic transport and separation resulted from magnetophoresis under high-gradient fields, changing the formation dynamics of the local columns and influencing the final state of the column system.

Huang, Yan; Li, Decai; Li, Feng; Zhu, Quanshui; Xie, Yu

2015-03-01

320

Levitation Performance of Two Opposed Permanent Magnet Pole-Pair Separated Conical Bearingless Motors  

NASA Technical Reports Server (NTRS)

In standard motor applications, rotor suspension with traditional mechanical bearings represents the most economical solution. However, in certain high performance applications, rotor suspension without contacting bearings is either required or highly beneficial. Examples include applications requiring very high speed or extreme environment operation, or with limited access for maintenance. This paper expands upon a novel bearingless motor concept, in which two motors with opposing conical air-gaps are used to achieve full five-axis levitation and rotation of the rotor. Force in this motor is created by deliberately leaving the motor s pole-pairs unconnected, which allows the creation of different d-axis flux in each pole pair. This flux imbalance is used to create lateral force. This approach is different than previous bearingless motor designs, which require separate windings for levitation and rotation. This paper examines the predicted and achieved suspension performance of a fully levitated prototype bearingless system.

Kascak, Peter; Jansen, Ralph; Dever, Timothy; Nagorny, Aleksandr; Loparo, Kenneth

2013-01-01

321

Local CP-violation and electric charge separation by magnetic fields from lattice QCD  

E-print Network

We study local CP-violation on the lattice by measuring the local correlation between the topological charge density and the electric dipole moment of quarks, induced by a constant external magnetic field. This correlator is found to increase linearly with the external field, with the coefficient of proportionality depending only weakly on temperature. Results are obtained on lattices with various spacings, and are extrapolated to the continuum limit after the renormalization of the observables is carried out. This renormalization utilizes the gradient flow for the quark and gluon fields. Our findings suggest that the strength of local CP-violation in QCD with physical quark masses is about an order of magnitude smaller than a model prediction based on nearly massless quarks in domains of constant gluon backgrounds with topological charge. We also show numerical evidence that the observed local CP-violation correlates with spatially extended electric dipole structures in the QCD vacuum.

G. S. Bali; F. Bruckmann; G. Endrodi; Z. Fodor; S. D. Katz; A. Schafer

2014-03-31

322

Evidence for Two Separate but Interlaced Components of the Chromospheric Magnetic Field  

NASA Technical Reports Server (NTRS)

Chromospheric fibrils are generally thought to trace out low-lying, mainly horizontal magnetic elds that fan out from flux concentrations in the photosphere. A high-resolution (approximately 0.1" per pixel) image, taken in the core of the Ca II 854.2 nm line and covering an unusually large area, shows the dark brils within an active region remnant as fine, looplike features that are aligned parallel to each other and have lengths comparable to a supergranular diameter. Comparison with simultaneous line-of-sight magnetograms confirms that the fibrils are centered above intranetwork areas (supergranular cell interiors), with one end rooted just inside the neighboring plage or strong unipolar network but the other endpoint less clearly defined. Focusing on a particular arcade-like structure lying entirely on one side of a lament channel (large-scale polarity inversion), we find that the total amount of positive-polarity flux underlying this "fibril arcade" is approximately 50 times greater than the total amount of negative-polarity flux. Thus, if the brils represent closed loops, they must consist of very weak fields (in terms of total magnetic flux), which are interpenetrated by a more vertical field that contains most of the flux. This surprising result suggests that the fibrils in unipolar regions connect the network to the nearby intranetwork flux, while the bulk of the network flux links to remote regions of the opposite polarity, forming a second, higher canopy above the fibril canopy. The chromospheric field near the edge of the network thus has an interlaced structure resembling that in sunspot penumbrae.

Reardom, K. P.; Wang, Y.-M.; Muglach, K.; Warren, H. P.

2011-01-01

323

Serum peptidome patterns of hepatocellular carcinoma based on magnetic bead separation and mass spectrometry analysis  

PubMed Central

Background Hepatocellular carcinoma (HCC) is one of the most common cancers in the world,and the identification of biomarkers for the early detection is a relevant target. The purpose of the study is to discover specific low molecular weight (LMW) serum peptidome biomarkers and establish a diagnostic pattern for HCC. Methods We undertook this pilot study using a combined application of magnetic beads with Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique and ClinPro Tools v2.2 to detect 32 patients with HCC, 16 patients with chronic hepatitis (CH), 16 patients with liver cirrhosis (LC) and 16 healthy volunteers. Results The results showed 49, 33 and 37 differential peptide peaks respectively appeared in HCC, LC and CH groups. A Supervised Neural Network (SNN) algorithm was used to set up the classification model. Eleven of the identified peaks at m/z 5247.62, 7637.05, 1450.87, 4054.21, 1073.37, 3883.64, 5064.37, 4644.96, 5805.51, 1866.47 and 6579.6 were used to construct the peptides patterns. According to the model, we could clearly distinguish between HCC patients and healthy controls as well as between LC or CH patients and healthy controls. Conclusions The study demonstrated that a combined application of magnetic beads with MALDI-TOF MB technique was suitable for identification of potential serum biomarkers for HCC and it is a promising way to establish a diagnostic pattern. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1503629821958720. PMID:23915185

2013-01-01

324

Dielectric-Loaded Microwave Cavity for High-Gradient Testing of Superconducting Materials  

E-print Network

A superconducting microwave cavity has been designed to test advanced materials for use in the accelerating structures contained within linear colliders. The electromagnetic design of this cavity produces surface magnetic fields on the sample wafer...

Pogue, Nathaniel Johnston

2011-08-08

325

A flexible lab-on-a-chip for the synthesis and magnetic separation of magnetite decorated with gold nanoparticles.  

PubMed

Magnetite decorated with gold nanoparticles (Fe3O4-AuNPs) is a ferrimagnetic material with unprecedented applications in immunosensors, as a contrast agent for imaging diagnosis, and for the photothermal ablation of tumor cells. Here, we show the preparation of controlled amounts of Fe3O4-AuNPs without organic solvents, surfactants, or heat treatment. For this, we have developed a customized natural-rubber-based microfluidic device (NRMD) as a flexible lab-on-a-chip for the decoration of Fe3O4 with AuNPs. With a novel NRMD configuration, monodisperse Fe3O4-NPs (? = 10 nm) decorated with AuNPs (? = 4 nm) were readily obtained. The AuNPs were homogenous in terms of their size and their distribution on the Fe3O4-NP surfaces. Furthermore, the lab-on-a-chip was projected with an internal system for magnetic separation, an innovation in terms of aqueous/carrier phase separation. Finally, the nanomaterials produced with this NRMD are free of organic solvents and surfactants, allowing them to be used directly for medical applications. PMID:25723569

Cabrera, Flávio C; Melo, Antonio F A A; de Souza, João C P; Job, Aldo E; Crespilho, Frank N

2015-03-31

326

Separation and purification of Si from solidification of hypereutectic Al-Si melt under rotating magnetic field  

NASA Astrophysics Data System (ADS)

A low-cost and high-efficiency method to purify Si directly from cheap MG-Si at low temperature was proposed and demonstrated in this paper, which used power frequency rotating magnetic field (RMF) to separate the primary Si from a hypereutectic Al-Si alloy and was followed by the acid peeling. The separation mechanism was based on the flow characteristic of melt under RMF and the cooling condition of the liquid metal. A Si-rich layer with Si content of 65-59 wt% was formed in the periphery of alloy, while the inner microstructure of the alloy was mainly the Al-Si eutectic structure. The refined silicon was collected after aqua regia leaching, and had much fewer typical impurities (Fe, Ti, Ca, B, P) than those in MG-Si, and the metallic impurities besides Al had removal fraction higher than 98%, which is mainly ascribed to the segregation effect of Al-30Si alloy during solidification under RMF.

Jie, J. C.; Zou, Q. C.; Wang, H. W.; Sun, J. L.; Lu, Y. P.; Wang, T. M.; Li, T. J.

2014-08-01

327

Evidence for Two Separate but Interlaced Components of the Chromospheric Magnetic Field  

NASA Technical Reports Server (NTRS)

Chromospheric fibrils are generally thought to trace out horizontal magnetic fields that fan out from flux concentrations in the photosphere. A high-resolution (0.2") image taken in the core of the Ca IJ854.2 nm line shows the dark fibrils within an active region remnant as fine, loop-like features that are aligned parallel to each other and have lengths on the order of a supergranular diameter (approx.30 Mm). Comparison with a line-of-sight magnetogram confirms that the fibrils are centered above intranetwork areas, with one end rooted just inside the neighboring plage or strong unipolar network but the other endpoint less clearly defined. Focusing on a particular arcade-like structure lying entirely on one side of a filament channel (large-scale polarity inversion), we find that the total amount of positive-polarity flux underlying this "fibril arcade' is 50 times greater than the total amount of negative-polarity flux. Thus, if the fibrils represent closed loops, they must consist of very weak fields (in terms of flux density), which are interpenetrated by a more vertical field that contains most of the flux. This surprising result suggests that the fibrils in unipolar regions connect the network to the nearby intranetwork flux, while the bulk of the network flux is diverted upward into the corona and connects to remote regions of the opposite polarity. We conclude that the chromospheric field near the edge of the network has an interlaced structure resembling that in sunspot penumbrae, with the fibrils representing the low-lying horizontal flux that remains trapped within the highly nonpotential chromospheric layer.

Muglach, K.; Reardon, K. P.; Wang, Y.-M.; Warren, H. P.

2012-01-01

328

Spatiotemporally separating electron and phonon thermal transport in L1{sub 0} FePt films for heat assisted magnetic recording  

SciTech Connect

We report the spatio-temporal separation of electron and phonon thermal transports in nanostructured magnetic L1{sub 0} FePt films at the nanometer length scale and the time domain of tens of picosecond, when heated with a pulsed laser. We demonstrate that lattice dynamics measured using the picosecond time-resolved laser pump/X-ray probe method on the FePt (002) and Ag (002) Bragg reflections from different layers provided the information of nanoscale thermal transport between the layers. We also describe how the electron and phonon thermal transports in nanostructured magnetic thin films were separated.

Xu, D. B., E-mail: dongbin.xu@seagate.com [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore (Singapore); Sun, C. J., E-mail: cjsun@aps.anl.gov, E-mail: msecgm@nus.edu.sg; Ho, P.; Chen, J. S.; Chow, G. M., E-mail: cjsun@aps.anl.gov, E-mail: msecgm@nus.edu.sg [Department of Materials Science and Engineering, National University of Singapore, 117576 Singapore (Singapore); Brewe, D. L.; Heald, S. M.; Zhang, X. Y. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Han, S.-W. [Department of Physics Education and Institute of Fusion Science, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2014-06-28

329

Chemically Driven Nanoscopic Magnetic Phase Separation at the SrTiO(3)(001)/La(1-x)Sr(x)CoO(3) Interface  

SciTech Connect

The degradation in magnetic properties in very thin film complex oxides is studied using SrTiO(3)(001)/La(1-x)Sr(x)CoO(3), providing unequivocal evidence for nanoscopic interfacial magnetic phase separation. Electron microscopy and spectroscopy reveal that this occurs due to inhomogeneity in local hole doping, driven by subtle, depthwise variations in the Sr and O stoichiometry. Simple thermodynamic and structural arguments for the origin of these variations are provided.

Torija, Maria [University of Minnesota; Sharma, M [University of Minnesota; Gazquez Alabart, Jaume [ORNL; Varela del Arco, Maria [ORNL; He, C. [University of Minnesota; Schmitt, J. [University of Minnesota; Borchers, J.A. [National Institute of Standards and Technology (NIST); Laver, M. [National Institute of Standards and Technology (NIST); El-Khatib, S. [University of Minnesota; Leighton, chris [University of Minnesota

2011-01-01

330

DEVELOPMENT OF THE HIGH-GRADIENT ELECTROSTATIC ACCELERATOR TECHNIQUES IN THE KYUSHU UNIVERSITY TANDEM  

E-print Network

bolted to the separating plates in each section. In order to enable this sort of construction all are adjusted such that the field strength multiplication by the edge effect becomes minimum. The strength of the gross field on the terminal sur- face is 150 kV/cm at 10 MV and the highest field strength as the result

Paris-Sud XI, Université de

331

New magnetic-enhanced adsorption process for wastewater treatment  

SciTech Connect

Radioactive and nonradioactive metal ion and particulate species in aqueous solutions present a formidable treatment problem for the nuclear and commercial industries. An economical and highly effective system for the treatment of wastewater containing these metal species is presented that uses a new magnetic enhanced adsorption technique. The process employs low-cost magnetite (FeO{center_dot}Fe{sub 2}O{sub 3}) supported on various organic and inorganic support media, and an external magnetic field to couple the inherent sorption properties of the magnetite with a high gradient magnetic separation technique. This combination of sorption techniques offers several advantages over current filtration and ion exchange systems and removes a variety of heavy metals and radioactive species. Filtration systems do not remove ionic species, and ion exchange systems can be plugged by particulate matter, which may limit the amount of exchange sites able to be accessed.

Cotten, G.B.; Navratil, J.D. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Sebesta, F. [Czech Tech Univ. (Czech Republic)

1999-09-01

332

Synthesis and characterization of magnetic hexacyanoferrate (II) polymeric nanocomposite for separation of cesium from radioactive waste solutions.  

PubMed

Nanocrystalline potassium zinc hexacyanoferrate loaded on nanoscale magnetite substrate was successfully synthesized for significantly enhanced removal of cesium from low-level radioactive wastes. A description was given for preparation and properties of these precursors. The physicochemical properties of these nanocomposites were determined using different techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Data clarified that supporting potassium zinc hexacyanoferrates on iron ferrite nanoparticles increased their thermal stability. Further, Fourier transform infrared spectra confirmed that the nanocomposites were well coordinated and incorporated in the polymer matrix. The average particle sizes, of these nanoparticles, determined by SEM had a good agreement with XRD results. Based on characterization data, the prepared zinc hexacyanoferrates were proposed to have a zeolitic rhombohedral structure with cavities can host alkali metal ions and water molecules. The magnetic analysis showed a super-paramagnetic behavior. Batch technique was applied to evaluate the influences of initial pH value, contact time, and competing cations on the efficiency of cesium removal. The sorption process was fast initially, and maximum separation was attained within 2h of contact. Cesium exchange was independent from pH value and deviate from ideal exchange phenomena. In neutral solutions, Cs(+) was retained through exchange with K(+); however, in acidic solution, phase transformation was proposed. Sorption capacity of these materials attained values amounted 1965 mg g(-1). The synthesized nanocomposites exhibited different affinities toward Cs(I), Co(II), and Eu(III) elements and showed a good ability to separate them from each other. PMID:23000210

Sheha, Reda R

2012-12-15

333

Magnetic, Durable, and Superhydrophobic Polyurethane@Fe3O4@SiO2@Fluoropolymer Sponges for Selective Oil Absorption and Oil/Water Separation.  

PubMed

Magnetic, durable, and superhydrophobic polyurethane (PU) sponges were fabricated by chemical vapor deposition (CVD) of tetraethoxysilane (TEOS) to bind the Fe3O4 nanoparticles tightly on the sponge and then dip-coating in a fluoropolymer (FP) aqueous solution. The sponges were characterized using scanning electron microscopy and other analytical techniques. The effects of CVD time of TEOS and FP concentration on wettability, mechanical properties, oil absorbency, and oil/water selectivity of the sponges were also investigated. The sponges exhibit fast magnetic responsivity and excellent superhydrophobicity/superoleophilicity (CAwater = 157° and CAoil ? 0°). The sponges also show very high efficiency in oil/water separation and could, driven by a magnet, quickly absorb floating oils on the water surface and heavy oils under water. Moreover, the PU@Fe3O4@SiO2@FP sponges could be used as membranes for oil/water separation and for continuous separation of large amounts of oil pollutants from the water surface with the help of a pump. The in turn binding of Fe3O4 nanoparticles, SiO2, and FP can also improve mechanical properties of the PU sponge. The sponges maintain the superhydrophobicity even when they are stretched with 200% strain or compressed with 50% strain. The sponges also show excellent mechanical stability, oil stability, and reusability in terms of superhydrophobicity and oil absorbency. The magnetic, durable, and superhydrophobic PU sponges are very promising materials for practical oil absorption and oil/water separation. PMID:25671386

Wu, Lei; Li, Lingxiao; Li, Bucheng; Zhang, Junping; Wang, Aiqin

2015-03-01

334

Proceedings of the 22nd sensor symposium, Oct. 20-21, 2005, Tokyo, pp 125 -128 Micro Magnetic Separator for Stem Cell Sorting System  

E-print Network

Separator for Stem Cell Sorting System Hiromichi Inokuchi Yuji Suzuki Nobuhide Kasagi Naoki Shikazono sorting (uIMCS) system for ex- tracting stem cells from peripheral blood. In this report, micro magnetic, in which pluripotent stem cells extracted from a patient's body are cultured to differen- tiate

Kasagi, Nobuhide

335

MAGNETIC DRUM SEPARATOR PERFORMANCE SCALPING SHREDDED TROMMEL OVERFLOW AT NOMINAL DESIGN CONDITIONS. TEST NO. 4.03, RECOVERY 1, NEW ORLEANS  

EPA Science Inventory

This report describes the first test of the shredded trommel overs magnetic drum separator at the New Orleans, Louisiana, resource recovery facility. Shredded trommel overs refers to waste which reports to the oversize discharge from the trommel and is subsequently shredded. For ...

336

Preparation of anionic polyelectrolyte modified magnetic nanoparticles for rapid and efficient separation of lysozyme from egg white.  

PubMed

Poly(sodium 4-styrenesulfonate) modified magnetic nanoparticles (PSS-MNPs) were successfully synthesized and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, vibrating sample magnetometry, and Fourier-transform infrared spectrometry. The PSS-MNPs were found to enable effective separation of lysozyme from egg white. The impacts of solution pH, ionic strength, and contact time on the adsorption process were investigated. The adsorption kinetic data were well fitted using a pseudo-second-order kinetic model and the adsorption equilibrium can be reached in 3min. The adsorption isotherm data could be well described by the Langmuir equation. The maximum adsorption capacity of PSS-MNPs for lysozyme was calculated to be 476.2mgg(-1) according to the Langmuir adsorption isotherm. The fast and efficient adsorption of lysozyme by PSS-MNPs was mainly based on electrostatic interactions between them. The adsorbed lysozyme can be eluted using 20mM phosphate buffer (pH 7.0) containing 1.0M NaCl with a recovery of 96%. The extracted lysozyme from egg white demonstrated high purity, retaining about 90.7% of total lysozyme activity. PMID:25728660

Chen, Jia; Lin, Yuexin; Jia, Li

2015-04-01

337

High-gradient microelectromechanical system quadrupole electromagnets for particle beam focusing and steering  

NASA Astrophysics Data System (ADS)

Recent advancements in microelectromechanical system (MEMS) fabrication techniques have enabled the batch-fabrication of quadrupole MEMS electromagnets producing 100 mT-scale field across sub-mm gaps with the potential for transformational advances in the field of compact high performance charged particle focusing and steering optics. The footprint of these in-vacuum focusing and steering optics can be as small as 3 mm ×3 mm ×0.5 mm . The low electromagnet impedance (58 m ? , 32 nH per pole) facilitates power-efficient operation and continuous or low duty cycle operation, and the individually controlled electromagnets allow combined dipole-quadrupole fields. Here we report on an experiment where these miniature devices have been used to focus and steer a 34 keV electron beam from a DC photogun, demonstrating the first application of magnetic MEMS to particle beam focusing.

Harrison, Jere; Hwang, Yongha; Paydar, Omeed; Wu, Jimmy; Threlkeld, Evan; Rosenzweig, James; Musumeci, Pietro; Candler, Rob

2015-02-01

338

Studies of the superconducting traveling wave cavity for high gradient LINAC  

E-print Network

Use of a traveling wave (TW) accelerating structure with a small phase advance per cell instead of standing wave may provide a significant increase of accelerating gradient in a superconducting linear accelerator. The TW section achieves an accelerating gradient 1.2-1.4 larger than TESLA-shaped standing wave cavities for the same surface electric and magnetic fields. Recent tests of an L-band single-cell cavity with a waveguide feedback demonstrated an accelerating gradient comparable to the gradient in a single-cell ILC-type cavity from the same manufacturer. This article presents the next stage of the 3- cell TW resonance ring development which will be tested in the traveling wave regime. The main simulation results of the microphonics and Lorentz Force Detuning (LFD) are also considered.

Avrakhov, Pavel; Kanareykin, Alexei; Solyak, Nikolay; Yakovlev, Vyacheslav P

2015-01-01

339

O-Allylation of phenols with allylic acetates in aqueous media using a magnetically separable catalytic system  

EPA Science Inventory

Allylic ethers were synthesized in water using magnetically recoverable heterogeneous Pd catalyst via O-allylation of phenols with allylic acetates under ambient conditions. Aqueous reaction medium, easy recovery of the catalyst using an external magnet, efficient recycling, and ...

340

Low-frequency resistance fluctuations in a single nanowire (diameter ? 45 nm) of a complex oxide and its relation to magnetic transitions and phase separation  

NASA Astrophysics Data System (ADS)

We report measurement of low frequency resistance noise spectroscopy in a single strand of a nanowire (NW) (diameter ? 45 nm) of a complex oxide manganite La0.5Sr0.5MnO3, that showed ferromagnetic transition (TC ? 315 K), an antiferromagnetic transition (TN ? 210 K) and a phase-separated region below TN. We demonstrated that noise spectroscopy in a single NW can cleanly detect the magnetic transitions including the phase-coexistence that may not be possible to do by magnetic measurements. The normalized noise in the single NW is an order less than that reported in ultralow-noise Si Junction Field Effect Transistor.

Datta, Subarna; Samanta, Sudeshna; Ghosh, Barnali; Raychaudhuri, A. K.

2014-08-01

341

Magselectofection: an integrated method of nanomagnetic separation and genetic modification of target cells.  

PubMed

Research applications and cell therapies involving genetically modified cells require reliable, standardized, and cost-effective methods for cell manipulation. We report a novel nanomagnetic method for integrated cell separation and gene delivery. Gene vectors associated with magnetic nanoparticles are used to transfect/transduce target cells while being passaged and separated through a high gradient magnetic field cell separation column. The integrated method yields excellent target cell purity and recovery. Nonviral and lentiviral magselectofection is efficient and highly specific for the target cell population as demonstrated with a K562/Jurkat T-cell mixture. Both mouse and human enriched hematopoietic stem cell pools were effectively transduced by lentiviral magselectofection, which did not affect the hematopoietic progenitor cell number determined by in vitro colony assays. Highly effective reconstitution of T and B lymphocytes was achieved by magselectofected murine wild-type lineage-negative Sca-1(+) cells transplanted into Il2rg(-/-) mice, stably expressing GFP in erythroid, myeloid, T-, and B-cell lineages. Furthermore, nonviral, lentiviral, and adenoviral magselectofection yielded high transfection/transduction efficiency in human umbilical cord mesenchymal stem cells and was fully compatible with their differentiation potential. Upscaling to a clinically approved automated cell separation device was feasible. Hence, once optimized, validated, and approved, the method may greatly facilitate the generation of genetically engineered cells for cell therapies. PMID:21357765

Sanchez-Antequera, Yolanda; Mykhaylyk, Olga; van Til, Niek P; Cengizeroglu, Arzu; de Jong, J Henk; Huston, Marshall W; Anton, Martina; Johnston, Ian C D; Pojda, Zygmunt; Wagemaker, Gerard; Plank, Christian

2011-04-21

342

Magnetic and Mechanical Analysis of the HQ Model Quadrupole Designs for LARP  

Microsoft Academic Search

Insertion quadrupoles with large bore and high gradient are required to upgrade the luminosity of the large hadron collider (LHC). The US LHC accelerator research program is developing Nb3Sn technology for the upgrade. This effort includes a series of 1 m long technology quadrupoles (TQ), to demonstrate the reproducibility at moderate field, and high-gradient quadrupoles (HQ) to explore the magnet

Helene Felice; Shlomo Caspi; Paolo Ferracin; Vadim Kashikhin; Igor Novitski; Gianluca Sabbi; Alexander Zlobin

2008-01-01

343

Exploring the effect of Al2O3 ALD coating on a high gradient ILC single-cell cavity  

SciTech Connect

Encouraged by work at Argonne National Lab, we investigated atomic layer deposition technique (ALD) for high gradient superconducting RF cavities at JLab with an ALD coating system of Old Dominion University located on the JLab site. The goal of this study was to look into the possibility of coating a dielectric layer on top of RF niobium surface at a lower temperature of 120 C as compared to ANL coatings at 200 C to preserve niobium pentoxide on niobium surface. The initial coatings showed complete, but non-uniform coatings of the surface with several areas exhibiting discoloration, which was probably due to the temperature variation across the cavity surface. The initial coating showed a high RF losses, which were improved after discolored areas on the beam tubes were removed with HF rinse of the beam tubes only. The best result was 2 109 low field Q0 and Eacc = 18 MV/m limited by available power.

Grigory Eremeev, Anne-Marie Valente, Andy Wu, Diefeng Gu

2012-07-01

344

Influence of the static high magnetic field on the liquid-liquid phase separation during solidifying the hyper-monotectic alloys  

NASA Astrophysics Data System (ADS)

Magnetic in-situ quenching refers to fixing and quenching the sample at a static high magnetic field (SHMF) up to 18 T; it has been achieved by a specially designed facility. Zn-7wt%Bi and Zn-10wt%Bi hyper-monotectic melts were quenched under different magnetic flux densities to investigate the influence of SHMF on the liquid-liquid phase separation process in solidifying hyper-monotectic alloys. Because this separation is mainly caused by the growth of minority phase droplets (Bi droplets in the present study), and such growth is attributed to the diffusion of Bi element and the coalescence between the droplets, the influence of SHMF on the growth of Bi droplets was analyzed. Results show that the imposed SHMF prevented the formation of layered structure in the Zn-10wt%Bi alloy and refined the Bi particles in the Zn-7wt%Bi alloy, which indicates that the SHMF retarded the liquid-liquid phase separation during solidifying the hyper-monotectic alloys. Indeed, the two motions of droplets in determining the coalescence, Marangoni migration and Stocks sedimentation, were slowed down by the applied SHMF. Analytical estimations of the magnitude of such damping effect have been made and show that the 18 T SHMF could reduce the speed of Stokes sedimentation and Marangoni migration of the minority phase droplets by about 95.5 % and 62.4 %, respectively.

Wang, J.; Zhong, Y. B.; Fautrelle, Y.; Zheng, T. X.; Li, F.; Ren, Z. M.; Debray, F.

2013-09-01

345

Novel Phase Separation and Magnetic Volume Tuning in Underdoped NaFe1-xCoxAs (x ˜0.01)  

NASA Astrophysics Data System (ADS)

NaFeAs is a quasi-2D pnictide parent compound with a weak magnetic moment and separate structural and antiferromagnetic transitions. Because Co doping leads to a superconductor with Tc˜20 K at a very low optimal doping of x = 0.02, NaFe1-xCoxAs is uniquely suited to sensitive studies of the cohabitation and competition between magnetism and superconductivity. Using NMR as a local probe of both antiferromagnetic order and superconductivity, we have compared Knight shifts and relaxation rates on the Na, As, and Co nuclei. Above Tc, we find weak doping inhomogeneity, in the form of residual paramagnetic regions with differing TN values, and a strongly field-controlled magnetic volume. Below Tc, we observe a strong competition between antiferromagnetism and superconductivity, in which the temperature is the dominant control parameter, suppressing the magnetic volume fraction very significantly in favor of the superconducting one, while the external field suppresses Tc. Our results suggest both a microscale phase separation in real space and in reciprocal space a competition between two order parameters requiring the same electrons on the quasi-2D Fermi surface.

Ma, Long; Dai, J.; Lu, X. R.; Tan, Guotai; Song, Yu; Dai, Pengcheng; Zhang, C. L.; Normand, B.; Yu, Weiqiang

2013-03-01

346

Recent advances in the application of core-shell structured magnetic materials for the separation and enrichment of proteins and peptides.  

PubMed

Many endogenous proteins/peptides and proteins/peptides with post-translational modifications (PTMs) are presented at extremely low abundance, and they usually suffer strong interference with highly abundant proteins/peptides as well as other contaminants, resulting in low ionization efficiency in MS analysis. Therefore, the separation and enrichment of proteins/peptides from complex mixtures is of great importance to the successful identification of them. Core-shell structured magnetic microspheres have been widely used in the enrichment and isolation of proteins/peptides, thanks to unique properties such as strong magnetic responsiveness, outstanding binding capacity, excellent biocompatibility, robust mechanical strength and admirable recoverability. The aim of this review is to update the advances in the application of core-shell structured magnetic materials for proteomics analysis, including the separation and enrichment of low-concentration proteins/peptides, the selective enrichment of phosphoproteins and the selective enrichment of glycoproteins, and to compare the enrichment performance of magnetic microspheres with different kinds of functionalization. PMID:24835765

Zhao, Man; Xie, Yiqin; Deng, Chunhui; Zhang, Xiangmin

2014-08-29

347

Study on the Effect of Melt Convection on Phase Separation Structures in Undercooled CuCo Alloys Using an Electromagnetic Levitator Superimposed with a Static Magnetic Field  

NASA Astrophysics Data System (ADS)

We studied the effect of melt convection on phase separation structures in undercooled Cu80Co20 alloys by using an electromagnetic levitator, where a static magnetic field was applied to control convection in the molten alloys. It was found that, when the static magnetic field was relatively small, dispersed structures with relatively fine Co-rich spheres distributed in the matrix of the Cu-rich phase were observed. However, a few large, coalesced Co-rich phases appeared in the Cu-rich matrix when the magnetic field exceeded a certain value, i.e., approximately 1.5 T in this study. The mean diameter of the droplet-shaped Co-rich phases distributed in the matrix of the Cu-rich phase increased gradually with the magnetic field and increased rapidly at approximately 1.5 T. Moreover, it was speculated from the result of periodic laser heating that the marked change in the phase separation structures at approximately 1.5 T might be due to a convective transition from turbulent flow to laminar flow in the molten sample, where the time variation of temperature in the lower part of the electromagnetically levitated molten sample was measured when the upper part of the sample was periodically heated.

Sugioka, Ken-ichi; Inoue, Takamitsu; Kitahara, Tsubasa; Kurosawa, Ryo; Kubo, Masaki; Tsukada, Takao; Uchikoshi, Masahito; Fukuyama, Hiroyuki

2014-08-01

348

Simple synthesis of functionalized superparamagnetic magnetite/silica core/shell nanoparticles and their application as magnetically separable high-performance biocatalysts  

SciTech Connect

We report on the facile large-scale synthesis of magnetite@silica core-shell nanoparticles by a simple addition of tetraethyl orthosilicate (TEOS) into reverse micelles during the formation of uniformly-sized magnetite nanoparticles. The size of magnetic core was determined by the ratio of solvent and surfactant in reverse micelle solution while the thickness of silica shell could be easily controlled by adjusting the amount of added TEOS. Amino group functional groups were grafted to the magnetic nanoparticles, and crosslinked enzyme clusters (CEC) were fabricated on the surface of magnetite@silica nanoparticles. The resulting hybrid materials of magnetite and CEC were magnetically separable, highly active, and stable enough to show no decrease of enzyme activity under rigorous shaking for more than 15 days.

Lee, Jinwoo; Lee, Youjin; Youn, Jongkyu; Na, Hyon Bin; Yu, Taekyung; Kim, Hwan O.; Lee, Sang-mok; Koo, Yoon-mo; Kwak, Ja Hun; Park, Hyun-Gyu; Chang, Ho Nam; Hwang, Misun; Park, Je-Geun; Kim, Jungbae; Hyeon, Taeghwan

2008-01-01

349

Magnetic field dependence of the magnetic phase separation in Pr1-xCaxMnO3 manganites studied by small-angle neutron scattering  

Microsoft Academic Search

Transport properties of manganese oxides suggest that their colossal magnetoresistance (CMR) is due to percolation between ferromagnetic metallic (FM) clusters in an antiferromagnetic insulating (AFI) matrix. We have studied small-angle neutron scattering under an applied magnetic field in CMR Pr1-xCaxMnO3 crystals for x around 0.33 . Quantitative analysis of the small-angle magnetic neutron scattering shows that the magnetic heterogeneities take

Damien Saurel; Annie Brûlet; André Heinemann; Christine Martin; Silvana Mercone; Charles Simon

2006-01-01

350

Electronic phase separation due to magnetic polaron formation in the semimetallic ferromagnet EuB6 — A weakly-nonlinear-transport study  

NASA Astrophysics Data System (ADS)

We report measurements of weakly nonlinear electronic transport, as measured by third-harmonic voltage generation V 3?, in the low-carrier density semimetallic ferromagnet EuB6, which exhibits an unusual magnetic ordering with two consecutive transitions at T_{c_1 } = 15.6K and T_{c_2 } = 12.5K. In contrast to the linear resistivity, the third-harmonic voltage is sensitive to the microgeometry of the electronic system. Our measurements provide evidence for magnetically-driven electronic phase separation consistent with the picture of percolation of magnetic polarons (MP), which form highly conducting magnetically ordered clusters in a paramagnetic and less conducting background. Upon cooling in zero magnetic field through the ferromagnetic transition, the dramatic drop in the linear resistivity at the upper transition T_{c_1 } coincides with the onset of nonlinearity, and upon further cooling is followed by a pronounced peak in V 3? at the lower transition T_{c_2 } . Likewise, in the paramagnetic regime, a drop of the material's magnetoresistance R( H) precedes a magnetic-fieldinduced peak in nonlinear transport. A striking observation is a linear temperature dependence of V {3?/peak}. We suggest a picture where at the upper transition T_{c_1 } the coalescing MP form a conducting path giving rise to a strong decrease in the resistance. The MP formation sets in at around T* ˜ 35K below which these entities are isolated and strongly fluctuating, while growing in number. The MP then start to form links at T_{c_1 } , where percolative electronic transport is observed. The MP merge and start forming a continuum at the threshold T_{c_2 } . In the paramagnetic temperature regime T_{c_1 } < T < T*, MP percolation is induced by a magnetic field, and the threshold accompanied by charge carrier delocalization occurs at a single critical magnetization.

Amyan, Adham; Das, Pintu; Müller, Jens; Fisk, Zachary

2013-05-01

351

Magnetically separable ternary hybrid of ZnFe2O4-Fe2O3-Bi2WO6 hollow nanospheres with enhanced visible photocatalytic property  

NASA Astrophysics Data System (ADS)

Magnetically separable ternary hybrid ZnFe2O4-Fe2O3-Bi2WO6 hollow nanospheres were designed and synthesized by an effective three-step approach. Specifically, using phenolic formaldehyde microspheres (PFS) as template direct the sequential coating of ?-Fe2O3/ZnFe2O4 layer and subsequent Bi2WO6 layer via impregnating-calcination process. The photocatalytic activity under visible light irradiation is in the order of ZnFe2O4-Fe2O3-Bi2WO6 > ZnFe2O4-Bi2WO6 > Bi2WO6 > ZnFe2O4-Fe2O3 > ZnFe2O4. The enhanced activity could be attributed to the cascade electron transfer from ZnFe2O4 to ?-Fe2O3 then to Bi2WO6 through the interfacial potential gradient in the ternary hybrid conduction bands, which facilitate the charge separation and retard the charge pair recombination. Furthermore, the ternary hybrid ZnFe2O4-Fe2O3-Bi2WO6 hollow nanospheres could be conveniently separated by using an external magnetic field, and be chemically and optically stable after several repetitive tests. The study also provides a general and effective method in the composite hollow nanomaterials with sound heterojunctions that may show a variety of applications.

Li, Junqi; Liu, Zhenxing; Zhu, Zhenfeng

2014-11-01

352

Bifunctional magnetic nanobeads for sensitive detection of avian influenza A (H7N9) virus based on immunomagnetic separation and enzyme-induced metallization.  

PubMed

Bifunctional magnetic nanobeads (bi-MBs) were fabricated by co-immobilizing target recognition molecules and signal molecules on a magnetic nanobead surface, which were used as both separation and enrichment carriers and signal carriers. The bi-MBs could capture and separate avian influenza A (H7N9) virus (H7N9 AIV) from complex samples efficiently based on the specific reaction between antigen-antibody and their good magnetic response, which simplified sample pretreatment and saved the detection time. Taking advantages of their high surface to volume ratio and rich surface functional groups, multiple alkaline phosphatase (ALP) signal molecules were tethered on the surface of bi-MBs which greatly amplified the detection signal. As an efficient signal amplification strategy, enzyme-induced metallization had been integrated with bi-MBs and anodic stripping voltammetry to construct an ultrasensitive electrochemical immunosensor for H7N9 AIV detection. Under the optimal conditions, the introduction of bi-MBs could amplify the detection signal in about four times compared with the same immunoassay without MBs, and the method showed a wide linear range of 0.01-20ng/mL with a detection limit of 6.8pg/mL. The electrochemical immunosensor provides a simple and reliable platform with high sensitivity and selectivity which shows great potential in early diagnosis of diseases. PMID:25643598

Wu, Zhen; Zhou, Chuan-Hua; Chen, Jian-Jun; Xiong, Chaochao; Chen, Ze; Pang, Dai-Wen; Zhang, Zhi-Ling

2015-06-15

353

A novel magnetically separable TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber with high photocatalytic activity under UV-vis light  

SciTech Connect

Graphical abstract: A novel magnetically separable composite photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technique, which can be reclaimed with a magnet, and the decolorizing efficiency of MB solution reached 95.87%. Highlights: Black-Right-Pointing-Pointer The composite TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers with diameter of 110 {+-} 28 nm have been successfully synthesized by the combination of sol-gel method and electrospinning technique. Black-Right-Pointing-Pointer The presence of Co{sup 2+} or/and Fe{sup 3+} ions may occupy some of the lattice sites of TiO{sub 2} to form an iron-titanium solid solution and narrow the band gap, which broadens the response region of visible light. Black-Right-Pointing-Pointer The resultant nanofibers not only have high decomposition efficiency with methylene blue (MB) under the UV irradiation, which is close to that of Degussa P25, but also can be separated with a magnet and avoid the secondary pollution of the treated water. -- Abstract: A novel magnetically separable heterogeneous photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technology, followed by heat treatment at 550 Degree-Sign C for 2 h. The phase structure, morphology and magnetic property of the composite nanofibers were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and vibrating sample magnetometer analysis. The photocatalytic studies of TiO{sub 2}/CoFe{sub 2}O{sub 4} fibers suggested that the presence of CoFe{sub 2}O{sub 4} not only enhanced the absorbance of UV light, but also broadened the response region to visible light. The decolorizing efficiency of methylene blue (MB) solution reaches 95.87% over TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers under 300 W Hg lamp after 5 h, which is close to that of Degussa P25. Furthermore, these fibers can be collected with a magnet for reuse and effectively avoid the secondary pollution of the treated water.

Li, Cong-Ju, E-mail: congjuli@gmail.com [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China)] [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China); Wang, Jiao-Na; Wang, Bin [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China)] [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China); Gong, Jian Ru, E-mail: gongjr@nanoctr.cn [National Center for Nanoscience and Technology, China, 11 Zhongguancun Beiyitiao, Beijing 100190 (China); Lin, Zhang [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian 350002 (China)] [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian 350002 (China)

2012-02-15

354

Popcorn-shaped magnetic core-plasmonic shell multifunctional nanoparticles for the targeted magnetic separation and enrichment, label-free SERS imaging, and photothermal destruction of multidrug-resistant bacteria.  

PubMed

Over the last few years, one of the most important and complex problems facing our society is treating infectious diseases caused by multidrug-resistant bacteria (MDRB), by using current market-existing antibiotics. Driven by this need, we report for the first time the development of the multifunctional popcorn-shaped iron magnetic core-gold plasmonic shell nanotechnology-driven approach for targeted magnetic separation and enrichment, label-free surface-enhanced Raman spectroscopy (SERS) detection, and the selective photothermal destruction of MDR Salmonella DT104. Due to the presence of the "lightning-rod effect", the core-shell popcorn-shaped gold-nanoparticle tips provided a huge field of SERS enhancement. The experimental data show that the M3038 antibody-conjugated nanoparticles can be used for targeted separation and SERS imaging of MDR Salmonella DT104. A targeted photothermal-lysis experiment, by using 670 nm light at 1.5 W cm(-2) for 10 min, results in selective and irreparable cellular-damage to MDR Salmonella. We discuss the possible mechanism and operating principle for the targeted separation, label-free SERS imaging, and photothermal destruction of MDRB by using the popcorn-shaped magnetic/plasmonic nanotechnology. PMID:23296491

Fan, Zhen; Senapati, Dulal; Khan, Sadia Afrin; Singh, Anant Kumar; Hamme, Ashton; Yust, Brian; Sardar, Dhiraj; Ray, Paresh Chandra

2013-02-18

355

Role of Nottingham and Thomson effects in heating of micro-protrusion in high-gradient accelerating structures  

NASA Astrophysics Data System (ADS)

It is widely accepted that one of the reasons for appearance of the RF breakdown which limits operation of high-gradient accelerating structures is the electron dark current [1]. This field emitted current, usually considered as a precursor of the breakdown, can be emitted from apexes of micro-protrusions on a structure surface. Therefore field and thermal processes in such protrusions deserve careful studies [2, 3]. The goal of our first study [3] was to analyze 2D process of RF field penetration inside protrusion of a metal with finite conductivity and to study corresponding Joule heating. In the current study, it is found that space charges can have a stabilizing effect on the electric field. We include a modification of the 1D model described in [4]. Moreover, we include into consideration, first, the Nottingham effect which may significantly change the protrusion heating. We also investigate the interplay between high temperature gradients and electric fields (Thomson heating).[4pt] [1] Wang and Loew, SLAC PUB 7684 October 1997.[0pt] [2] K.L. Jensen, Y.Y. Lau, D.W. Feldman, P.G. O'Shea, Phys. Rev. ST Accel. Beams 11, 081001(2008).[0pt] [3] Kashyn et al, AAC-2010.[0pt] [4] K.L. Jensen, J. LEbowitz, Y.Y. LAu, J. Luginsland, Journal of Applied Physics 111, 054917(2012).

Keser, Aydin; Nusinovich, Gregory; Kashyn, Dmytro; Antonsen, Thomas

2012-10-01

356

Measurements of Ion Beam Production and Neutron Yields in the LLNL High Gradient Z-Pinch Experiment  

NASA Astrophysics Data System (ADS)

Dense plasma focus (DPF) z-pinch plasmas are known to produce abundant neutrons and particle beams, but the mechanisms behind the high gradient fields in DPFs are not well understood. We have a 4 MeV deuteron beam that can be used to probe the electric field gradients produced by the DPF experiment at LLNL. This information can be used in conjunction with fully kinetic simulations of DPF plasmas to further our understanding of the mechanisms that produce these beams. This knowledge allows us to optimize the gradients in the DPF for next generation compact accelerators. The beam and neutron output from the LLNL DPF have been characterized. We present measurements of beam and neutron production for a variety of pinch currents. Acceleration gradients greater than 0.5 MV/cm have been achieved, a record for sub-kJ DPFs. Our upgraded gun design allows a probe beam to pass through the plasma, allowing for the first-ever measurements of DPF gradients. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the Laboratory Directed Research and Development Program (11-ERD-063) at LLNL.

Ellsworth, J. L.; Falabella, S.; Rusnak, B.; Schmidt, A.; Tang, V.

2012-10-01

357

A self-consistent two-dimensional resistive fluid theory of field-aligned potential structures including charge separation and magnetic and velocity shear  

NASA Technical Reports Server (NTRS)

A self-consistent two-fluid theory that includes the magnetic field and shear patterns is developed to model stationary electrostatic structures with field-aligned potential drops. Shear flow is also included in the theory since this seems to be a prominent feature of the structures of interest. In addition, Ohmic dissipation, a Hall term, and pressure gradients in a generalized Ohm's law, modified for cases without quasi-neutrality, are included. In the analytic theory, the electrostatic force is balanced by field-aligned pressure gradients (i.e., thermal effects in the direction of the magnetic field) and by pressure gradients and magnetic stresses in the perpendicular direction. Within this theory, simple examples of applications are presented to demonstrate the kind of solutions resulting from the model. The results show how the effects of charge separation and shear in the magnetic field and the velocity can be combined to form self-consistent structures such as are found to exist above the aurora, suggested also in association with solar flares.

Hesse, Michael; Birn, Joachim; Schindler, Karl

1990-01-01

358

Strain-induced oxygen defect formation and interfacial magnetic phase separation in SrTiO3(001)/La1-xSrxCoO3  

NASA Astrophysics Data System (ADS)

The remarkable functionality and epitaxial compatibility of complex oxides provides many opportunities for new physics and applications in oxide heterostructures. Perovskite manganites and cobaltites provide excellent examples, being of interest for solid oxide fuel cells, catalysis, ferroelectric RAM, gas sensing, resistive switching memory, and oxide spintronics. However, the same delicate balance between phases that provides this diverse functionality also leads to a serious problem - the difficulty of maintaining desired properties close to the interface with other oxides. Although this problem is widespread, manifests itself in several ways, and could present a significant roadblock to the development of heterostructured devices for oxide electronics, there is no consensus as to its origin, or even whether it is driven by electronic or chemical effects. In this work, using SrTiO3(001)/La1-xSrxCoO3 as a model system, we have combined epitaxial growth via high pressure oxygen sputtering with high resolution x-ray diffraction, atomic resolution electron microscopy and spectroscopy, and detailed magnetic, transport, and neutron scattering measurements to determine the fundamental origin of the deterioration in interfacial transport and magnetism. The effect is found to be due to nanoscopic magnetic phase separation in the near-interface region driven by a significant depletion in interfacial hole doping due to accumulation of O vacancies. This occurs due to a novel mechanism for accommodation of lattice mismatch with the substrate based on formation and long-range ordering of O vacancies, thus providing a fundamental link between strain state and O vacancy density. Further impacts of the O vacancy ordering and interfacial magnetic phase separation, such as formation of a spin-state superlattice and an extraordinary coercivity enhancement, will also be discussed. Work in collaboration with M. Sharma, M. Torija, J. Schmitt, C. He, S. El-Khatib, J. Gazquez, M. Varela, M. Laver and J. Borchers.

Leighton, Chris

2012-02-01

359

Magnetically-Separable and Highly-Stable Enzyme System Based on Crosslinked Enzyme Aggregates Shipped in Magnetite-Coated Mesoporous Silica  

SciTech Connect

Magnetically-separable and highly-stable enzyme system was developed by adsorption of enzymes in superparamagnetic hierarchically ordered mesocellular mesoporous silica (M-HMMS) and subsequent enzyme crosslinking. Superparamagnetic nanoparticles were homogeneously incorporated into hierarchically-ordered mesocellular mesoporous silica (HMMS) by the decomposition of preformed iron propionate complex. The size of incorporated superparamagnetic 15 nanoparticles was around 5 nm, generating a magnetically separable host with high pore volumes and large pores (M-HMMS). ?-chymotrypsin (CT) was adsorbed into M-HMMS with high loading (~30 wt%) in less than 30 minutes. Glutaraldehyde (GA) treatment of adsorbed CT resulted in nanometer scale crosslinked enzyme aggregates in M-HMMS (CLEA-M). The activity of these CT aggregates in M-HMMS (CLEA-M-CT) was 34 times than that of simply adsorbed CT in M20 HMMS, due to an effective prevention of enzyme leaching during washing via a ship-in-a-bottle approach. CLEA-M-CT maintained the intial activity not only under shaking (250 rpm) for 30 days, but also under recycled uses of 35 times. The same approach was employed for the synthesis of CLEA-M of lipase (CLEA-M-LP), and proven to be effective in improving the loading, activity, and stability of enzyme when compared to those of adsorbed LP in M-HMMS.

Lee, Jinwoo; Na, Hyon Bin; Kim, Byoung Chan; Lee, Jin Hyung; Lee, Byoungsoo; Kwak, Ja Hun; Hwang, Yosun; Park, Je-Geun; Gu, Man Bock; Kim, Jaeyun; Joo, Jin; Shin, Chae-Ho; Grate, Jay W.; Hyeon, Taeghwan; Kim, Jungbae

2009-10-15

360

Field alignment of quadrupole magnets for the LHC interaction regions  

Microsoft Academic Search

High-gradient superconducting quadrupole magnets are being developed by the US LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. Determination of the magnetic axis for alignment of these magnets will be performed using a single stretched wire system. These measurements will be done both at room and cryogenic temperatures with very long wire lengths, up to 20

J. DiMarco; H. Glass; M. J. Lamm; P. Schlabach; C. Sylvester; J. C. Tompkins; I. Krzywinski

2000-01-01

361

The general concept of signal–noise separation (SNS): mathematical aspects and implementation in magnetic resonance spectroscopy  

Microsoft Academic Search

Magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) are increasingly recognized as potentially key modalities\\u000a in cancer diagnostics. It is, therefore, urgent to overcome the shortcomings of current applications of MRS and MRSI. We explain\\u000a and substantiate why more advanced signal processing methods are needed, and demonstrate that the fast Padé transform (FPT),\\u000a as the quotient of two polynomials, is

Dževad Belki?; Karen Belki?

2009-01-01

362

Fabrication of magnetically separable fluorescent terbium-based MOF nanospheres for highly selective trace-level detection of TNT.  

PubMed

In this work, we present novel kinds of Fe3O4@Tb-BTC magnetic metal-organic framework (MOF) nanospheres which possess both magnetic characteristics and fluorescent properties using a layer by layer assembly technique. The structure and morphology of the as-prepared Fe3O4@Tb-BTC were systematically characterized and it was applied in detection of nitroaromatic explosives, such as 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 2-nitrotoluene (2-NT), 4-nitrotoluene (4-NT), nitrobenzene (NB) and picric acid (PA). The results indicate that the fluorescence intensity of Fe3O4@Tb-BTC can be quenched by all analytes studied in the present work. Remarkably, the as-synthesized nanospheres exhibit high sensitivity for 2,4,6-trinitrotoluene (TNT) detection with Ksv value of (94?800 M(-1)). Besides, the magnetic nanospheres can be easily recycled, which makes it more convenient for reutilization and friendly to the environment. The results show that it has broad application prospects in the detection of nitroaromatic explosives. PMID:24452313

Qian, Jing-Jing; Qiu, Ling-Guang; Wang, Yi-Min; Yuan, Yu-Peng; Xie, An-Jian; Shen, Yu-Hua

2014-03-14

363

Solid-solid grinding/templating route to magnetically separable nitrogen-doped mesoporous carbon for the removal of Cu(2+) ions.  

PubMed

N-doped ordered mesoporous carbon materials (NOMC) with 2D hexagonal symmetry structure were synthesized via a facile solid-solid grinding/templating route, in which the ionic liquids (ILs) of 1-cyanoethyl-3-methylimidazolium chloride and SBA-15 were employed as the precursor and hard template, respectively. The as-synthesized NOMC features with a uniform mesoporous size (3.5nm), ropes-like morphology (0.4-1?m in length) and high surface area (803m(2)/g). The quantitative analysis revealed the nitrogen content on the surface of NOMC is 5.5at%. Magnetic iron nanoparticles were successfully embedded into the carbon matrix by introducing iron chloride to the mixture of SBA-15 and ILs during the synthesis process. The NOMC-Fe composite possessed superior adsorption capacity of Cu(2+) ions (23.6mg/g). Kinetic and isothermal analysis demonstrated the strong interactions between Cu(2+) ion and the adsorbent. Furthermore, the composite was magnetically separable from solution under an external magnetic field and thus displayed a superior reusability in the recycling test. PMID:25072134

Chen, Aibing; Yu, Yifeng; Zhang, Yue; Xing, Tingting; Wang, Yanyan; Zhang, Yexin; Zhang, Jian

2014-08-30

364

Quantitative estimation of left ventricular ejection fraction from mitral valve E-point to septal separation and comparison to magnetic resonance imaging.  

PubMed

This study tested the hypothesis that the mitral valve E point-to-septal separation (EPSS) can be used to quantify the left ventricular (LV) ejection fraction (EF) on a continuous scale rather than simply as "normal" or "reduced." After excluding 5 patients with mitral valve prostheses, asymmetric septal hypertrophy, or significant aortic insufficiency, EPSS was measured in 42 patients by 3 independent observers on a cardiac magnetic resonance image identical to the echocardiographic parasternal long-axis view. In each patient, the reference standard LVEF was calculated from the magnetic resonance short-axis cross-sectional stack images by Simpson's rule and ranged from 11% to 72%. For all 42 patients, linear regression revealed the relation magnetic resonance imaging (MRI) LVEF = 75.5 - 2.5. EPSS (millimeters). Correlation between EPSS and the MRI LVEF for the 3 observers agreed closely, ranging from r = 0.78 to r = 0.82 (SEE 9 to 10), with similar regression coefficients. After blinded segmental wall motion scoring of the gated magnetic resonance cine images of the left ventricle in each patient, correlations, SEEs, and regression coefficients were found to be very similar in the 21 patients with the most homogenous wall motion, compared with the 21 patients with the most heterogenous wall motion. In conclusion, clinically useful quantitative prediction of the LVEF as a continuous variable can be obtained from the EPSS with a simple linear regression equation in a substantial portion of patients and may be a useful adjunct for assessment of LV function. PMID:16377299

Silverstein, Jay R; Laffely, Nicholas H; Rifkin, Robert D

2006-01-01

365

Low gravity phase separator  

NASA Technical Reports Server (NTRS)

An apparatus is described for phase separating a gas-liquid mixture as might exist in a subcritical cryogenic helium vessel for cooling a superconducting magnet at low gravity such as in planetary orbit, permitting conservation of the liquid and extended service life of the superconducting magnet.

Smoot, G. F.; Pope, W. L.; Smith, L. (inventors)

1977-01-01

366

Warm Magnetic Field Measurements of LARP HQ Magnet  

Microsoft Academic Search

The US-LHC Accelerator Research Program is developing and testing a high-gradient quadrupole (HQ) magnet, aiming at demonstrating the feasibility of NbSn technologies for the LHC luminosity upgrade. The 1 m long HQ magnet has a 120 mm bore with a conductor-limited gradient of 219 T\\/m at 1.9 K and a peak field of 15 T. HQ includes accelerator features such

X. Wang; P. Wanderer; S. Caspi; D. Cheng; D. Dietderich; H. Felice; P. Ferracin; R. Hafalia; J. Joseph; J. Lizarazo; M. Martchevskii; C. Nash; G. L. Sabbi; C. Vu; J. Schmalzle; G. Ambrosio; R. Bossert; G. Chlachidze; J. DiMarco; V. Kashikhin

2011-01-01

367

Separation and extraction of Co(II) using magnetic chitosan nanoparticles grafted with ?-cyclodextrin and determination by FAAS  

NASA Astrophysics Data System (ADS)

A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective sorption of Co(II) ions using magnetic chitosan nanoparticles grafted with ?-cyclodextrin at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 mL elution volume) for a 100 mL sample volume. The limit of detection of the proposed method is 1.0 ng mL-1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% ( n = 10). Accuracy and applicability of the method was estimated using test samples of natural and model water with different amounts of Co(II).

Moghimi, Ali

2014-12-01

368

Magnetism  

NSDL National Science Digital Library

This webpage is part of the University Corporation for Atmospheric Research (UCAR) Windows to the Universe program. It describes the nature and configuration of magnetic fields, which are the result of moving electric charges, including how they cause magnetic objects to orient themselves along the direction of the magnetic force points, which are illustrated as lines. Magnetic field lines by convention point outwards at the north magnetic pole and inward at the south magnetic pole. The site features text, scientific illustrations and an animation. Text and vocabulary are selectable for the beginning, intermediate, or advanced reader.

University Corporation for Atmospheric Research Windows to the Universe team

2007-12-12

369

Optimization of a phase separation based magnetic-stirring salt-induced liquid-liquid microextraction method for determination of fluoroquinolones in food.  

PubMed

Herein, we developed a novel integrated apparatus to perform phase separation based on magnetic-stirring, salt-induced, liquid-liquid microextraction for determination of five fluoroquinolones in animal-based foods by HPLC analysis. The novel integrated apparatus consisted of three simple HDPE (high density polyethylene) parts that were used to separate the solvent from the aqueous solution prior to retrieving the extractant. The extraction parameters were optimized using the response surface method based on central composite design: 791 ?L of acetone solvent, 2.5 g of Na2SO4, pH 1.7, 3.0 min of stir time, and 5.5 min centrifugation. The limits of detection were 0.07-0.53 ?g kg(-1) and recoveries were 91.6-105.0% for the five fluoroquinolones from milk, eggs and honey. This method is easily constructed from inexpensive materials, extraction efficiency is high, and the approach is compatible with HPLC analysis. Thus, it has excellent prospects for sample pre-treatment and analysis of fluoroquinolones in animal-based foods. PMID:25577068

Gao, Ming; Wang, Huili; Ma, Meiping; Zhang, Yuna; Yin, Xiaohan; Dahlgren, Randy A; Du, Dongli; Wang, Xuedong

2015-05-15

370

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples  

NASA Astrophysics Data System (ADS)

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00 ?g mL-1, 5.0 ng mL-1, 0.9993 and 2.8% (n = 3, c = 4.00 ?g mL-1), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples.

Chen, Jieping; Zhu, Xiashi

2015-02-01

371

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples.  

PubMed

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00 ?g mL(-1), 5.0 ng mL(-1), 0.9993 and 2.8% (n=3, c=4.00 ?g mL(-1)), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples. PMID:25238184

Chen, Jieping; Zhu, Xiashi

2015-02-25

372

Nb{sub 3}Sn magnets for a muon collider  

SciTech Connect

High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approximately}15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient quadrupole magnets.

Gupta, R.C.; Green, M.A.; Scanlan, R.M. [Lawrence Berkeley National Lab., CA (United States); Palmer, R. [Brookhaven National Lab., Upton, NY (United States)

1998-07-01

373

Nb3Sn Magnets for a Muon Collider  

SciTech Connect

High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approx} 15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient quadrupole magnets.

Gupta, R.C.; Green, M.A.; Scanlan, R.M.; Palmer, R.

1998-06-20

374

Kinetic, isotherm and thermodynamic investigations of phosphate adsorption onto core-shell Fe3O4@LDHs composites with easy magnetic separation assistance.  

PubMed

In this study, three different magnetic core-shell Fe3O4@LDHs composites, Fe3O4@Zn-Al-, Fe3O4@Mg-Al-, and Fe3O4@Ni-Al-LDH were prepared via a rapid coprecipitation method for phosphate adsorptive removal. The composites were characterized by XRD, FTIR, TEM, VSM and BET analyses. Characterization results proved the successful synthesis of core-shell Fe3O4@LDHs composites with good superparamagnetisms. Batch experiments were conducted to study the adsorption efficiency of phosphate. Optimal conditions for the phosphate adsorption were obtained: 0.05g of adsorbent, solution pH of 3, and contact time of 60min. Proposed mechanisms for the removal of phosphate species onto Fe3O4@LDHs composites at different initial solution pH were showed. The kinetic data were described better by the pseudo-second-order kinetic equation and KASRA model. The adsorption isotherm curves showed a three-region behavior in the ARIAN model. It had a good fit with Langmuir model and the maximum adsorption capacity followed the order of Fe3O4@Zn-Al-LDH>Fe3O4@Mg-Al-LDH>Fe3O4@Ni-Al-LDH. Thermodynamic analyses indicated that the phosphate adsorption process was endothermic and spontaneous in nature. The three Fe3O4@LDHs composites could be easily separated from aqueous solution by the external magnetic field in 10s. These novel magnetic core-shell Fe3O4@LDHs adsorbents may offer a simple single step adsorption treatment option to remove phosphate from water without the requirement of pre-/post-treatment for current industrial practice. PMID:25778739

Yan, Liang-Guo; Yang, Kun; Shan, Ran-Ran; Yan, Tao; Wei, Jing; Yu, Shu-Jun; Yu, Hai-Qin; Du, Bin

2015-06-15

375

Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol complex from environmental and biological samples.  

PubMed

A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid-liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40?gL(-1) and 100, respectively. The relative standard deviation (RSD) of 50?gL(-1) Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1-101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples. PMID:24398463

Khan, Sumaira; Kazi, Tasneem Gul; Soylak, Mustafa

2014-04-01

376

New magnetic field-enhanced process for the treatment of aqueous wastes  

SciTech Connect

A new magnetic adsorbent material, called magnetic polyamine-epichlorohydrin (MPE) resin, was prepared by attaching activated magnetite to the outer surface of polyamine-epichlorohydrin resin beads. Experiments were carried out in the presence of a 0.3-tesla magnetic field to investigate the removal of actinides (plutonium and americium) from pH 12 wastewater using this new resin. The results demonstrated that the MPE resin has a significantly enhanced capacity for actinides over conventional ferrite-based surface complexation adsorption processes (where no field is applied) and over traditional high-gradient magnetic separation (HGMS) processes that remove suspended particles. This enhancement was attributed to the presence and subsequent removal of suspended actinide nanoparticles through an HGMS effect, with the magnetite acting as a very effective HGMS element. A theoretical analysis verified this supposition by showing that under adequate pHs and particle-particle separations, the attractive long-ranged magnetic force exerted by magnetite on suspended particles of plutonium hydroxide was greater in magnitude than other forces (e.g., van der Waals, electrostatic, viscous, and Brownian forces).

Ebner, A.D.; Ritter, J.A.; Ploehn, H.J. [Univ. of South Carolina, Columbia, SC (United States)] [Univ. of South Carolina, Columbia, SC (United States); Kochen, R.L. [Rocky Flats Environmental Technology Site, Golden, CO (United States)] [Rocky Flats Environmental Technology Site, Golden, CO (United States); Navratil, J.D. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States)] [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States)

1999-04-01

377

Magnetic state of the structural separated anion-deficient La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} manganite  

SciTech Connect

The results of neutron diffraction studies of the La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} compound and its behavior in an external magnetic field are stated. It is established that in the 4-300 K temperature range, two structural perovskite phases coexist in the sample, which differ in symmetry (groups R3-bar c and I4/mcm). The reason for the phase separation is the clustering of oxygen vacancies. The temperature (4-300 K) and field (0-140 kOe) dependences of the specific magnetic moment are measured. It is found that in zero external field, the magnetic state of La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} is a cluster spin glass, which is the result of frustration of Mn{sup 3+}-O-Mn{sup 3+} exchange interactions. An increase in external magnetic field up to 10 kOe leads to fragmentation of ferromagnetic clusters and then to an increase in the degree of polarization of local spins of manganese and the emergence of long-range ferromagnetic order. With increasing magnetic field up to 140 kOe, the magnetic ordering temperature reaches 160 K. The causes of the structural and magnetic phase separation of this composition and formation mechanism of its spin-glass magnetic state are analyzed.

Trukhanov, S. V., E-mail: truhanov@ifttp.bas-net.by; Trukhanov, A. V. [Scientific Practical Materials Research Centre of NAS of Belarus (Belarus); Vasiliev, A. N. [Moscow State University (Russian Federation); Balagurov, A. M. [Joint Institute for Nuclear Research (Russian Federation); Szymczak, H. [Institute of Physics, PAS (Poland)

2011-11-15

378

Magnetism  

NSDL National Science Digital Library

This radio broadcast discusses the history of magnetism from the time of its discovery by an apocryphal Greek sheperd until the late 16th century and the work of William Gilbert. There is also discussion of who pioneered the study of magnetism, what theories they constructed from its curious abilities, and how the power of the magnet was brought out of the realm of magic and into the service of science. The broadcast concludes with a discussion of why magnetism is still mysterious and how the modern search for the single magnetic pole, or magnetic monopole, could provide a fundamental unit of magnetism, essential for ultimate explanation. The broadcast is 41 minutes and 45 seconds in length.

379

The superconducting OGMS separator optimization  

Microsoft Academic Search

The constructional parameters of the electromagnet influence the efficiency of the OGMS (open gradient magnetic separation) process. An analysis of the relationships between the superconducting magnet dimensions and the efficiency of the separator for the paramagnetic (?=5e-3) and ferromagnetic (iron) particles with the diameters 20 ?m and 100 ?m for different medium velocities is presented. The mathematical model of the

Tadeusz Janowski; Slawomir Kozak

1993-01-01

380

Induced migration of non-magnetic particles and fabrication of metallic-based graded materials by applying a strong magnetic field  

Microsoft Academic Search

Strong magnetic fields e.g., 10 T are now frequently used during materials preparation. In the present paper, a method of metal-ceramics graded materials preparation is proposed by applying a strong magnetic field with a high gradient. Experimental and theoretical analyses are performed to investigate the effect of the strong magnetic field on the migration and interaction behavior of diamagnetic oxide

Z. Sun; M. Guo; J. Vleugels; B. Blanpain; O. van der Biest

2011-01-01

381

Progress and Plans for R&D and the Conceptual Design of the ILC High Gradient Structures  

Microsoft Academic Search

Gradients and Q?s in the dominant ILC candidate structure have shown steady improvement, reaching 35 — 40 MV\\/m over the last year using the best techniques of electropolishing, high pressure rinsing and 120... C baking for 48 hours. Progress and plans for these structures are reviewed. Above 40 MV\\/m, the surface magnetic field encroaches the range of the rf critical

H. Padamsee

2005-01-01

382

Overview of LARP Magnet R&D  

Microsoft Academic Search

This paper presents the main areas of magnet R&D for a LHC Luminosity Upgrade carried on through the LHC Accelerator Research Program (LARP). Development of Nb3Sn high gradient, large aperture quadrupoles is taking place at Berkeley, Fermilab, and Brookhaven.

Peter Wanderer

2009-01-01

383

Immunochromatographic strip for rapid detection of Cronobacter in powdered infant formula in combination with silica-coated magnetic nanoparticles separation and 16S rRNA probe.  

PubMed

Here we developed a sensitive, specific, and rapid immunochromatographic strip test for the detection of Cronobacter. Silica-coated magnetic nanoparticles were used to separate nucleic acid from Cronobacter lysate and eliminate the interference of food matrices successfully. A couple of 5'-end labeled probes, which was complementary to the 16S ribosomal DNA of Cronobacter, was used to hybridize with the nucleic acid. The hybrid product, labeled with digoxigenin on one side and biotin on the other side, was directly submitted to the immunochromatographic strip test and the anti-digoxigenin monoclonal antibody was immobilized on nitrocellulose membrane in the test line. The visualization was achieved by gold nanoparticles conjugated to streptavidin, and double red bands appearing in both test and control line indicated a positive result of the presence of Cronobacter in testing sample. The detection limit was 10(7) cfu mL(-1) in pure culture. After silica-coated magnetic nanoparticles treatment, the detection limit was 10(5) and 10(6) cfu mL(-1) in pure culture and powdered infant formula, respectively, and maintained stable even under the interference of 10(8) cfu mL(-1)Salmonella typhimurium. Furthermore, 100 positive powdered infant formula samples spiked 10(8) cfu mL(-1)Cronobacter and 20 negative samples with none bacteria were tested by the strip, and the sensitivity and specificity of the test were both as high as 100%. This approach showed promise for microbial detection concerning food safety or clinical diagnosis. PMID:24907538

Chen, Fei; Ming, Xing; Chen, XingXing; Gan, Min; Wang, BaoGui; Xu, Feng; Wei, Hua

2014-11-15

384

Size-regulated group separation of CoFe2O4 nanoparticles using centrifuge and their magnetic resonance contrast properties  

PubMed Central

Magnetic nanoparticle (MNP)-based magnetic resonance imaging (MRI) contrast agents (CAs) have been the subject of extensive research over recent decades. The particle size of MNPs varies widely and is known to influence their physicochemical and pharmacokinetic properties. There are two commonly used methods for synthesizing MNPs, organometallic and aqueous solution coprecipitation. The former has the advantage of being able to control the particle size more effectively; however, the resulting particles require a hydrophilic coating in order to be rendered water soluble. The MNPs produced using the latter method are intrinsically water soluble, but they have a relatively wide particle size distribution. Size-controlled water-soluble MNPs have great potential as MRI CAs and in cell sorting and labeling applications. In the present study, we synthesized CoFe2O4 MNPs using an aqueous solution coprecipitation method. The MNPs were subsequently separated into four groups depending on size, by the use of centrifugation at different speeds. The crystal shapes and size distributions of the particles in the four groups were measured and confirmed by transmission electron microscopy and dynamic light scattering. Using X-ray diffraction analysis, the MNPs were found to have an inverse spinel structure. Four MNP groups with well-selected semi-Gaussian-like diameter distributions were obtained, with measured T2 relaxivities (r2) at 4.7 T and room temperature in the range of 60 to 300 mM?1s?1, depending on the particle size. This size regulation method has great promise for applications that require homogeneous-sized MNPs made by an aqueous solution coprecipitation method. Any group of the CoFe2O4 MNPs could be used as initial base cores of MRI T2 CAs, with almost unique T2 relaxivity owing to size regulation. The methodology reported here opens up many possibilities for biosensing applications and disease diagnosis. PACS 75.75.Fk, 78.67.Bf, 61.46.Df PMID:24004536

2013-01-01

385

Size-regulated group separation of CoFe2O4 nanoparticles using centrifuge and their magnetic resonance contrast properties  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticle (MNP)-based magnetic resonance imaging (MRI) contrast agents (CAs) have been the subject of extensive research over recent decades. The particle size of MNPs varies widely and is known to influence their physicochemical and pharmacokinetic properties. There are two commonly used methods for synthesizing MNPs, organometallic and aqueous solution coprecipitation. The former has the advantage of being able to control the particle size more effectively; however, the resulting particles require a hydrophilic coating in order to be rendered water soluble. The MNPs produced using the latter method are intrinsically water soluble, but they have a relatively wide particle size distribution. Size-controlled water-soluble MNPs have great potential as MRI CAs and in cell sorting and labeling applications. In the present study, we synthesized CoFe2O4 MNPs using an aqueous solution coprecipitation method. The MNPs were subsequently separated into four groups depending on size, by the use of centrifugation at different speeds. The crystal shapes and size distributions of the particles in the four groups were measured and confirmed by transmission electron microscopy and dynamic light scattering. Using X-ray diffraction analysis, the MNPs were found to have an inverse spinel structure. Four MNP groups with well-selected semi-Gaussian-like diameter distributions were obtained, with measured T2 relaxivities ( r 2) at 4.7 T and room temperature in the range of 60 to 300 mM-1s-1, depending on the particle size. This size regulation method has great promise for applications that require homogeneous-sized MNPs made by an aqueous solution coprecipitation method. Any group of the CoFe2O4 MNPs could be used as initial base cores of MRI T2 CAs, with almost unique T2 relaxivity owing to size regulation. The methodology reported here opens up many possibilities for biosensing applications and disease diagnosis.

Kang, Jongeun; Lee, Hyunseung; Kim, Young-Nam; Yeom, Areum; Jeong, Heejeong; Lim, Yong Taik; Hong, Kwan Soo

2013-09-01

386

Magnetism  

NSDL National Science Digital Library

This overview of magnetism provides a brief history prior to 1600 and continues with the work of William Gilbert, Hans Christian Oersted, and Andre-Marie Ampere in describing and exploring the magnetosphere and learning the role that electric current plays in producing magnetism. Magnetic field lines are then discussed, citing the work of Michael Faraday. The work of James Clerk Maxwell and Heinrich Hertz is mentioned in a discussion of the relationship of light waves and radio waves as part of the electromagnetic spectrum.

David Stern

387

A revised velocity-reversal and sediment-sorting model for a high-gradient, pool-riffle stream  

USGS Publications Warehouse

Sediment-sorting processes related to varying channel-bed morphology were investigated from April to November 1993 along a 1-km pool-riffle and step-pool reach of North Saint Vrain Creek, a small mountain stream in the Rocky Mountains of northern Colorado. Measured cross-sectional areas of flow were used to suggest higher velocities in pools than in riffles at high flow. Three hundred and sixteen tracer particles, ranging in size from 16 mm to 256 mm, were placed in two separate pool-riffle-pool sequences and used to assess sediment-sorting patterns and sediment-transport competence variations. Tracer-particle depositional evidence indicated higher sediment-transport competence in pools than in riffles at high flow. Pool-riffle sediment sorting may be created by velocity reversals, and more localized sorting results from gravitational forces along the upstream sloping portion of the channel bed located at the downstream end of pools.

Thompson, D.M.; Wohl, E.E.; Jarrett, R.D.

1996-01-01

388

Multi-MW 22.8 GHz Harmonic Multiplier - RF Power Source for High-Gradient Accelerator R&D  

SciTech Connect

Electrodynamic and particle simulation studies have been carried out to optimize design of a two-cavity harmonic frequency multiplier, in which a linear electron beam is energized by rotating fields near cyclotron resonance in a TE111 cavity in a uniform magnetic field, and in which the beam then radiates coherently at the nth harmonic into a TEn11 output cavity. Examples are worked out in detail for 7th and 2nd harmonic converters, showing RF-to-RF conversion efficiencies of 45% and 88%, respectively at 19.992 GHz (K-band) and 5.712 GHz (C-band), for a drive frequency of 2.856 GHz. Details are shown of RF infrastructure (S-band klystron, modulator) and harmonic converter components (drive cavity, output cavities, electron beam source and modulator, beam collector) for the two harmonic converters to be tested. Details are also given for the two-frequency (S- and C-band) coherent multi-MW test stand for RF breakdown and RF gun studies.

Jay L. Hirshfield

2012-07-26

389

Prediction of separation process results in OGMS  

Microsoft Academic Search

The wet magnetic separation of ore fine particles containing 32-40% of iron in the form of hematite is experimentally investigated. The extraction parameter distribution W(X) of particles is obtained at the open-gradient magnetic separator, X = kappaD2, kappa - being the relative magnetic susceptibility of a paramagnetic or diamagnetic particle, D, its size.

V. L. Borzov; T. Yu. Dmitrievskaya; A. N. Piskunov; V. K. Fedorov; P. A. Cheremnykh; V. N. Yaremenko

1990-01-01

390

Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC)  

SciTech Connect

The low-{beta} magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 10{sup 34}cm{sup -2}s{sup -1}. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-{beta} magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents the instrumentation used to optimize the engineering process and operation of the final focusing/defocusing quadrupole magnets for the first years of operation.

Darve, C.; /Fermilab; Balle, C.; Casas-Cubillos, J.; Perin, A.; Vauthier, N.; /CERN

2011-05-01

391

GMAG PhD Dissertation Research Award Talk: Dynamic Magnetic Traps for Particle Self-Assembly and Lab-on-Chip Applications  

NASA Astrophysics Data System (ADS)

Micro-patterned Permalloy thin films serve as an excellent means to architect the spatial profile of magnetic fields with the tunable, high gradients required to manipulate objects with weak induced magnetic moments. In this presentation, I will highlight two projects carried out during my PhD studies. These findings demonstrate the functionalities achieved through carefully designed patterns of different sizes and shapes (e.g. circular, triangular, octagonal profiles): (i) By tuning a precessing magnetic field in conjunction with such Permalloy patterns, microsphere (i.e. dipole) cluster structures ranging from closely packed to frustrated and to plum-pudding-like planar lattices are stabilized. Such self-assembly of components at the micro to nanometer range not only support a rich variety of physical phenomena, but also have applications, for example, as filters or force probes and field-tunable photonic crystals. (ii) Mobile magnetic trap arrays consisting of Permalloy disks have enabled rapid transport of magnetic beads or immunomagnetically labeled cells across surfaces. Integration of these arrays with microfluidic droplet technology allows separation of labeled cells and their subsequent encapsulation into picoliter-sized droplets. The droplets serve as isolated containers for individual cells to be probed without cross-contamination. The separation-encapsulation function could become a critical component in point-of-care single-cell analysis platforms.

Chen, Aaron

2013-03-01

392

Basal electric and magnetic fields of celestial bodies come from positive-negative charge separation caused by gravitation of quasi-Casimir pressure in weak interaction  

NASA Astrophysics Data System (ADS)

According to f =d(mv)/dt=m(dv/dt)+ v(dm/dt), a same gravitational formula had been de-duced from the variance in physical mass of QFT and from the variance in mass of inductive energy-transfer of GR respectively: f QF T = f GR = -G (mM/r2 )((r/r)+(v/c)) when their interaction-constants are all taken the experimental values (H05-0029-08, E15-0039-08). f QF T is the quasi-Casimir pressure. f GR is equivalent to Einstein's equation, then more easy to solve it. The hypothesis of the equivalent principle is not used in f QF T , but required by f GR . The predictions of f QF T and f GR are identical except that f QF T has quantum effects but f GR has not and f GR has Lense-Thirring effect but f QF T has not. The quantum effects of gravitation had been verified by Nesvizhevsky et al with the ultracold neutrons falling in the earth's gravitational field in 2002. Yet Lense-Thirring effect had not been measured by GP-B. It shows that f QF T is essential but f GR is phenomenological. The macro-f QF T is the statistic average pressure collided by net virtual neutrinos ? 0 flux (after self-offset in opposite directions) and in direct proportion to the mass. But micro-f QF T is in direct proportion to the scattering section. The electric mass (in inverse proportion to de Broglie wavelength ?) far less than nucleonic mass and the electric scattering section (in direct proportion to ?2 ) far large than that of nucleon, then the net ? 0 flux pressure exerted to electron far large than that to nucleon and the electric displacement far large than that of nucleon, it causes the gravitational polarization of positive-negative charge center separation. Because the gravity far less than the electromagnetic binding force, in atoms the gravitational polarization only produces a little separation. But the net ? 0 flux can press a part freedom electrons in plasma of ionosphere into the earth's surface, the static electric force of redundant positive ions prevents electrons from further falling and till reach the equilibrium of stable spatial charge distribution, which is just the cause of the geomagnetic field and the geo-electric field (the observational value on the earth surface is about 120 V/m downward equivalent to 500000 Coulomb negative charges in the earth surface). All celestial bodies are gravitation sources and attract the molecules and ions in space to its circumference by the gravitation of own and other celestial bodies, e.g., all planets in the solar system have their own atmospheres. Therefore, the origin mechanism of geo-electric and geomagnetic fields caused by gravitation is very universal, at least it is appli-cable to all the planets in the solar system. For planets, the joint result of the gravitations of the planets and the sun makes the negative charges and dipolar charges distributed in the surfaces of the celestial bodies. The quicker the rotation is, the larger the angular momentum U is, then larger the accompanying current and magnetic moment P, it accord a experiential law found by subsistent observational data of all celestial bodies in solar system: P = -G 1/2 U cos ? / c (1), ? is the angle between the net ? 0 flux direction (mark by CMB) and the rotational axis of celestial body (Chen Shao-Guang, Chinese Science Bulletin, 26,233,1981). Uranian and Neptunian P predicted with Eq.(1) in 1981 are about -3.4•1028 Gs•cm3 and 1.9•1028 Gs•cm3 respectively (use new rotate speed measured by Voyager 2). The P measured by Voyager 2 in 1986 and 1989 are about -1.9 •1028 Gs•cm3 and 1.5•1028 Gs•cm3 respectively (the contribution of quadrupole P is converted into the contribution of dipole P alone). The neutron star pos-sesses much high density and rotational speed because of the conservation of the mass and the angular momentum during the course of the formation, then has strong gravity and largerU. From Eq.(1) there is a larger P and extremely strong surface magnetic field in neutron star. The origin mechanism of basal electric and magnetic fields of celestial bodies will affect directly all fields refer

Chen, Shao-Guang

393

Separating Mixtures  

NSDL National Science Digital Library

Students learn how to classify materials as mixtures, elements or compounds and identify the properties of each type. The concept of separation of mixtures is also introduced since nearly every element or compound is found naturally in an impure state such as a mixture of two or more substances, and it is common that chemical engineers use separation techniques to separate mixtures into their individual components. For example, the separation of crude oil into purified hydrocarbons such as natural gas, gasoline, diesel, jet fuel and/or lubricants.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

394

Surface molecular imprinting onto fluorescein-coated magnetic nanoparticles via reversible addition fragmentation chain transfer polymerization: a facile three-in-one system for recognition and separation of endocrine disrupting chemicals.  

PubMed

In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads via reversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms)=3.67 emu g(-1)). The hybrids bind the original template 17?-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. PMID:21063623

Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

2011-01-01

395

Surface molecular imprinting onto fluorescein-coated magnetic nanoparticles via reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals  

NASA Astrophysics Data System (ADS)

In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads via reversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17?-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads via reversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17?-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic supplementary information (ESI) available: Supplementary figure S1. The hysteresis loop of Fe3O4 (a), Fe3O4@SiO2 (b), and Fe3O4@SiO2-Dye-SiO2 (c). See DOI: 10.1039/c0nr00614a

Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

2011-01-01

396

Progress on Design and Construction of a MuCool Coupling Solenoid Magnet  

Microsoft Academic Search

The MuCool program undertaken by the US Neutrino Factory and Muon Collider Collaboration is to study the behavior of muon ionization cooling channel components. A single superconducting coupling solenoid magnet is necessary to pursue the research and development work on the performance of high gradient, large size RF cavities immersed in magnetic field, which is one of the main challenges

L. Wang; Xiao Kun Liu; FengYu Xu; S. Y. Li; Heng Pan; Hong Wu; Xinglong Guo; ShiXian Zheng; M. A. Green; D. R. Li; S. P. Virostek; M. S. Zisman

2010-01-01

397

Design study of a superconducting insertion quadrupole magnet for the Large Hadron Collider  

Microsoft Academic Search

The conceptual design study of a high gradient superconducting insertion quadrupole magnet has been carried out in collaboration between KEK and CERN for the Large Hadron Collider (LHC) to be built at CERN. A model magnet design has been optimized to provide a nominal design field gradient of 240 T\\/m with a bore aperture of 70 mm and an operational

A. Yamamoto; K. Tsuchiya; N. Higashi; T. Nakamoto; T. Ogitsu; N. Ohuchi; T. Shintomi; A. Terashima; G. Kirby; R. Ostojic; T. M. Taylor

1997-01-01

398

Parallel Simulation of HGMS of Weakly Magnetic Nanoparticles in Irrotational Flow of Inviscid Fluid  

PubMed Central

The process of high gradient magnetic separation (HGMS) using a microferromagnetic wire for capturing weakly magnetic nanoparticles in the irrotational flow of inviscid fluid is simulated by using parallel algorithm developed based on openMP. The two-dimensional problem of particle transport under the influences of magnetic force and fluid flow is considered in an annular domain surrounding the wire with inner radius equal to that of the wire and outer radius equal to various multiples of wire radius. The differential equations governing particle transport are solved numerically as an initial and boundary values problem by using the finite-difference method. Concentration distribution of the particles around the wire is investigated and compared with some previously reported results and shows the good agreement between them. The results show the feasibility of accumulating weakly magnetic nanoparticles in specific regions on the wire surface which is useful for applications in biomedical and environmental works. The speedup of parallel simulation ranges from 1.8 to 21 depending on the number of threads and the domain problem size as well as the number of iterations. With the nature of computing in the application and current multicore technology, it is observed that 4–8 threads are sufficient to obtain the optimized speedup. PMID:24955411

Hournkumnuard, Kanok

2014-01-01

399

Fault Separation  

NSDL National Science Digital Library

Students use gestures to explore the relationship between fault slip direction and fault separation by varying the geometry of faulted layers, slip direction, and the perspective from which these are viewed.

Carol Ormand

400

Stereoisomers Separation  

NASA Astrophysics Data System (ADS)

The use of capillary electrophoresis for enantiomer separation and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be separated show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the separation based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers separation and determination are presented.

Wieczorek, Piotr

401

Isotope separation apparatus  

DOEpatents

Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates.

Arnush, Donald (Rancho Palos Verdes, CA); MacKenzie, Kenneth R. (Pacific Palisades, CA); Wuerker, Ralph F. (Palos Verdes Estates, CA)

1980-01-01

402

Chemical Separations  

NSDL National Science Digital Library

This site contains complete notes in a PowerPoint-like presentation for a chemical separations course. It covers a wide variety of topics, including distillation, extraction, gas chromatography, liquid chromatograpy, chromatography theory, instrumentation, electrophoresis, field flow fractionation, and affinity chromatography. It covers these topics thoroughly using a clear, consistent, and simple presentation style. Links to major topics like GC, LC, and electrophoresis provide specific information about the theory, instrumentation, and practice related to these techniques. The site also contains many annimations illustrating important separation processes.

403

Nano-CuFe2O4 as a magnetically separable and reusable catalyst for the synthesis of diaryl/aryl alkyl sulfides via cross-coupling process under ligand-free conditions.  

PubMed

An efficient protocol was developed for the CuFe(2)O(4) nanopowder-catalyzed aryl-sulfur bond formation between aryl halide and thiol/disulfide. A variety of aryl sulfides were synthesized in impressive yields with good chemoselectivity and functional group tolerance in the presence of a catalytic amount of CuFe(2)O(4), Cs(2)CO(3) as base, in nitrogen atmosphere, under ligand-free conditions, in DMSO as solvent at 100 °C. The catalyst is air-stable, inexpensive, magnetically separable and recyclable up to four cycles. PMID:21769376

Swapna, Kokkirala; Murthy, Sabbavarapu Narayana; Jyothi, Mocharla Tarani; Nageswar, Yadavalli Venkata Durga

2011-09-01

404

Chemical separations  

SciTech Connect

This volume collects papers presented at a conference on chemical separation. Topics include: field-flow fractionation, chromatography, electrophoresis, solvent extraction in metals recovery, extraction of uranium and plutonium from nitric acid, modeling of flow fields in oscillating droplets, inclusion, and membrane processes.

King, J.C.; Navratil, J.D.

1986-01-01

405

Chromatographic Separations  

NSDL National Science Digital Library

This interactive applet provides a simulation of the separation of a mixture of 5 substances across a chromatographic column. The effect of changing various chromatographic factors can simultaneously be seen in the time-dependent dedistribution of analytes along the column along with the development of the chromatogram.

406

Magnetic Materials  

NSDL National Science Digital Library

Students begin working on the grand challenge of the unit by thinking about the nature of metals and quick, cost-effective means of separating different metals, especially steel. They arrive at the idea, with the help of input from relevant sources, to use magnets, but first they must determine if the magnets can indeed isolate only the steel.

2014-09-18

407

Gas separating  

DOEpatents

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

Gollan, Arye (Newton, MA)

1988-01-01

408

Gas separating  

DOEpatents

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

Gollan, Arye Z. [Newton, MA

1990-12-25

409

Separation system  

DOEpatents

A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. Separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.

Rubin, Leslie S. (Newton, MA)

1986-01-01

410

Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions  

NASA Astrophysics Data System (ADS)

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate) (P(HEMA- co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA- co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

Rittich, Bohuslav; Španová, Alena; Šálek, Petr; N?mcová, Petra; Trachtová, Št?pánka; Horák, Daniel

2009-05-01

411

Phase separation in thermoelectric delafossite CuFe1-xNixO2 observed by soft x-ray magnetic circular dichroism  

NASA Astrophysics Data System (ADS)

Electronic structures of Ni-doped CuFe1-xNixO2 delafossite oxides (0 ? x ? 0.03) have been investigated by employing soft x-ray magnetic circular dichroism (XMCD). Finite XMCD signals are observed for Fe, Ni, and Cu 2p states, and valence states of Cu, Fe, and Ni ions are nearly monovalent (Cu+), trivalent (Fe3+), and divalent (Ni2+), respectively, for all x ? 0.03. Tiny magnetic impurities could be detected by employing XMCD. Fe and Ni 2p XMCD signals are identified due to ferrimagnetic spinel impurities of CuFe2O4 and NiFe2O4. XMCD signals for Cu 2p states arise from divalent Cu2+ ions. Thermoelectrical properties are found to be very sensitive to the very little impurity phase present in delafossite oxides.

Kang, J.-S.; Kim, D. H.; Hwang, Jihoon; Lee, Eunsook; Nozaki, T.; Hayashi, K.; Kajitani, T.; Park, B.-G.; Kim, J.-Y.; Min, B. I.

2011-07-01

412

Application of magnetic solid phase extraction for separation and determination of aflatoxins B ? and B? in cereal products by high performance liquid chromatography-fluorescence detection.  

PubMed

A simple and sensitive method based on the magnetic solid phase extraction with modified magnetic nanoparticles followed by high performance liquid chromatography with fluorescence detection has been developed for extraction and determination of aflatoxins B1 (AFB1) and B2 (AFB2) in cereal products. Magnetic nanoparticle coated with 3-(trimethoxysilyl)-1-propanthiol (TMSPT) and modified with 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) was used as an antibody-free adsorbent. Under the optimal conditions, the calibration curves for AFB1 and AFB2 were linear in the ranges of 0.2-15 ?g L(-1) and 0.04-3 ?g L(-1), respectively. Detection limit was 0.041 ?g L(-1) for AFB1 and 0.013 ?g L(-1) for AFB2. The proposed method was successfully applied to the determination of AFB1 and AFB2 in spiked corn and rice samples with an average recovery of 93.5%. The results demonstrated that the developed method is simple, rapid, inexpensive, accurate and remarkably free from interference effects. PMID:24814005

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-06-01

413

Measuring and controlling the transport of magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Despite the large body of literature describing the synthesis of magnetic nanoparticles, few analytical tools are commonly used for their purification and analysis. Due to their unique physical and chemical properties, magnetic nanoparticles are appealing candidates for biomedical applications and analytical separations. Yet in the absence of methods for assessing and assuring their purity, the ultimate use of magnetic particles and heterostructures is likely to be limited. For magnetic nanoparticles, it is the use of an applied magnetic flux or field gradient that enables separations. Flow based techniques are combined with applied magnetic fields to give methods such as magnetic field flow fractionation and high gradient magnetic separation. Additional techniques have been explored for manipulating particles in microfluidic channels and in mesoporous membranes. This thesis further describes development of these and new analytical tools for separation and analysis of colloidal particles is critically important to enable the practical use of these, particularly for medicinal purposes. Measurement of transport of nanometer scale particles through porous media is important to begin to understand the potential environmental impacts of nanomaterials. Using a diffusion cell with two compartments separated by either a porous alumina or polycarbonate membrane as a model system, diffusive flux through mesoporous materials is examined. Experiments are performed as a function of particle size, pore diameter, and solvent, and the particle fluxes are monitored by the change in absorbance of the solution in the receiving cell. Using the measured extinction coefficient and change in absorbance of the solution as a function of time, the fluxes of 3, 8, and 14 nm diameter CoFe2O4 particles are determined as they are translocated across pores with diameters 30, 50, 100, and 200 nm in hexane and aqueous solutions. In general, flux decreases with increasing particle size and increases with pore diameter. We find that fluxes are faster in aqueous solutions than in hexane, which is attributed to the hydrophilic nature of the porous membranes and differences in wettability. The impact of an applied magnetic flux gradient, which induces magnetization and motion, on permeation is also examined. Surface chemistry plays an important role in determining flux through porous media such as in the environment. Diffusive flux of nanoparticles through alkylsilane modified porous alumina is measured as a model for understanding transport in porous media of differing surface chemistries. Experiments are performed as a function of particle size, pore diameter, attached hydrocarbon chain length and chain terminus, and solvent. Particle fluxes are monitored by the change in absorbance of the solution in the receiving side of a diffusion cell. In general, flux increases when the membranes are modified with alkylsilanes compared to untreated membranes, which is attributed to the hydrophobic nature of the porous membranes and differences in wettability. We find that flux decreases, in both hexane and aqueous solutions, when the hydrocarbon chain lining the interior pore wall increases in length. The rate and selectivity of transport across these membranes is related to the partition coefficient (Kp) and the diffusion coefficient (D) of the permeating species. By conducting experiments as a function of initial particle concentration, we find that KpD increases with increasing particle size, is greater in alkylsilane--modified pores, and larger in hexane solution than water. The impact of the alkylsilane terminus (--CH3, --Br, --NH2, --COOH) on permeation in water is also examined. In water, the highest KpD is observed when the membranes are modified with carboxylic acid terminated silanes and lowest with amine terminated silanes as a result of electrostatic effects during translocation. Finally, the manipulation of magnetic nanoparticles for the controlled formation of linked nanoparticle assemblies between microfluidic channels by the application of an external

Stephens, Jason R.

414

Artwork Separation  

NASA Technical Reports Server (NTRS)

Under a grant from California Institute of Technology, Jet Propulsion Laboratory (JPL) and LACMA (Los Angeles County Museum of Art) used image enhancement techniques to separate x-ray images of paintings when one had been painted on top of another. The technique is derived from computer processing of spacecraft-acquired imagery, and will allow earlier paintings, some of which have been covered for centuries, to be evaluated. JPL developed the program for "subtracting" the top painting and enhancing the bottom one, and believes an even more advanced system is possible.

1983-01-01

415

Gas separating  

DOEpatents

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

Gollan, A.Z.

1990-12-25

416

Acoustophoresis separation method  

NASA Technical Reports Server (NTRS)

A method and apparatus are provided for acoustophoresis, i.e., the separation of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a frequency tuned to or harmonized with the point of resonance of the species to be separated. This wave causes the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio frequency tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a frequency corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal.

Heyman, Joseph S. (inventor)

1993-01-01

417

Capella: Separating the Giants  

NASA Astrophysics Data System (ADS)

Faint Object Camera (FOC) images from the Hubble Space Telescope are presented showing a clean spatial separation of the two giants in the Capella system (? Aur, HD 34029). These images were taken at elongation (Dec. 21, 1997) when the apparent separation of the stars, 55 milliarcseconds, corresponded to 4 pixels in the FOC image. Careful use of the objective prism mode of the FOC yielded ultraviolet spectra with dispersion perpendicular to the axis of separation of the two stars. The relative flux contributions to prominent UV emission lines such as O I ? 1305, C II ? 1335 and Si IV ? 1397 can then be derived. This direct measurement of each star's emission can be compared to the total spectrum as obtained by STIS at a similar phase (Sept. 12, 1999) where multiple gaussian fitting must be invoked to separate the individual contributions. The relation of these ratios to the known evolutionary states of the two stars, and the consequences for theories of stellar magnetic dynamos are discussed. This research is supported in part by an STScI Grant to SAO.

Young, P. R.; Dupree, A. K.; Gilliland, R. L.

1999-12-01

418

Efficiency of a superconducting OGMS separator  

Microsoft Academic Search

In conjunction with an investigation of superconducting open-gradient magnetic separators, the mathematical model of the particle trajectory passing through the separator has been produced. The method of calculating the main parameters of the separator is presented. Results of calculations by the proposed method have been confirmed in two experimental separators for cleaning industrial water. Efficiencies of up to 12.2 m3\\/h

T. Janowski; S. Kozak

1990-01-01