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Calibración del separador magnético de alta intensidad magnet-lift mlh (13) 111-5 para su uso en el laboratorio de termocronología de la UCV/ Calibration of a high intensity magnet-lift mlh (13) 111-5 magnetic separator for use in the thermochronology laboratory of the UCV  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish En este artículo se presenta la calibración del separador magnético de alta intensidad Magnet-lift MLH (13) 111-5 existente en el Laboratorio de Termocronología de la Universidad Central de Venezuela con la finalidad de separar magnéticamente minerales pertenecientes a areniscas y muestras graníticas para su posterior fechado por el método de huellas de fisión. Los resultados obtenidos de esta calibración fueron aplicados a una muestra de 10 kilogramos pertenecie (more) ntes a unaconcentración inicial de minerales de la Formación Betijoque del flanco norte de Los Andes Venezolanos. Se concluye que el Magnet-lift presenta amplias ventajas con respecto a los separadores magnéticos convencionales y además optimiza el tiempo de procesamiento de rocas detríticas que posteriormente serán fechadas por el método de datación empleado eneste laboratorio con el fin de discriminar la edad del último evento tecto-térmico ocurrido en la zona de estudio. Abstract in english In this article we present the calibration of a high intensity Magnet-lift MLH (13) 111-5 magnetic separator located in the Thermochronology Laboratory of the Universidad Central de Venezuela with the purpose of magnetically separating minerals of sandstone and granite samples to be subsequently subjected to the fission track dating method (FTDM). The results of this calibration were applied to 10 kilogram sample belonging to an initial concentration of minerals of Betijo (more) que´s Formation on the north flank of Venezuelans Andes. We conclude that the Magnet-lift presents a number of advantages with regard to conventional magnetic separators as well as optimizing the preparation time of detritic rocks for their dating by the fission track method.

MAURICIO, A; BERMÚDEZ, CELLA; ANAYA, RAQUEL C

2007-01-01

2

Magnetic separator  

Energy Technology Data Exchange (ETDEWEB)

A magnetic separator is proposed which includes a housing with sleeves for input and output of the processed material and magnetic system which is arranged in the housing. In order to increase the output of the separator, the magnetic system is made in the form of a belt made of magnetic-hardening material which is bent in a spiral. The shape of the spiral is determined from equations written in cylindrical coordinates and based on the following parameters: axis of the magnetic system; radius of curvature; angle between the positive direction of the X axis and the radius r; coefficient which determines the spiral spacing; coefficient which determines the screw spacing; argument of the z function, argument of the r function; thickness of the belt; width of the belt; and diameter of the housing.

1982-01-01

3

Magnetic separations in biotechnology.  

UK PubMed Central (United Kingdom)

Magnetic separations are probably one of the most versatile separation processes in biotechnology as they are able to purify cells, viruses, proteins and nucleic acids directly from crude samples. The fast and gentle process in combination with its easy scale-up and automation provide unique advantages over other separation techniques. In the midst of this process are the magnetic adsorbents tailored for the envisioned target and whose complex synthesis spans over multiple fields of science. In this context, this article reviews both the synthesis and tailoring of magnetic adsorbents for bioseparations as well as their ultimate application.

Borlido L; Azevedo AM; Roque AC; Aires-Barros MR

2013-06-01

4

Continuous magnetic separator and process  

Energy Technology Data Exchange (ETDEWEB)

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

5

Magnetic separation of particles  

International Nuclear Information System (INIS)

Particles are released at end of a vibrating table supplied from a hopper and fall past a device in which parallel superimposed super conducting cables produce a magnetic field in the region of the descending particles. The table is level with the uppermost cable or raised above the table by the radius of the cable. The cables are held in a clamp and cooled in a cryostat vessel. The side of the device is provided with a wiper. Strongly magnetic particles are attracted to the side and can be removed by the wiper. Weakly magnetic particles fall into a box and non-magnetic particles into another box. A movable wall enables adjustment of the relative widths of the boxes. Under certain conditions the deflection of the particles is independent of their shape and size. (author)

1987-09-14

6

Magnetic separation of particles  

Energy Technology Data Exchange (ETDEWEB)

Particles are released at end of a vibrating table supplied from a hopper and fall past a device in which parallel superimposed super conducting cables produce a magnetic field in the region of the descending particles. The table is level with the uppermost cable or raised above the table by the radius of the cable. The cables are held in a clamp and cooled in a cryostat vessel. The side of the device is provided with a wiper. Strongly magnetic particles are attracted to the side and can be removed by the wiper. Weakly magnetic particles fall into a box and non-magnetic particles into another box. A movable wall enables adjustment of the relative widths of the boxes. Under certain conditions the deflection of the particles is independent of their shape and size. (author).

Gerber, R.; Watmough, M.H.

1989-05-24

7

Magnetic separation of antibiotics by electrochemical magnetic seeding  

Energy Technology Data Exchange (ETDEWEB)

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 [Department of Agricultural Engineering and Socio Economics, Kobe University, Nada, Kobe 657-8501 (Japan); Beneragama, N; Umetsu, K [Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan)], E-mail: ihara@port.kobe-u.ac.jp

2009-03-01

8

High gradient magnetic separation using superconducting bulk magnets  

Science.gov (United States)

We aim to apply the superconducting bulk magnets to high gradient magnetic separation technique. Two bulk magnets are face-to-face arranged and a pipe stuffed magnetic filters composed of ferromagnetic wires is placed between the magnetic poles. We setup the magnetic separation system and test it using slurry mixed with hematite particles (Fe2O3). Y123 bulk superconductors are magnetized by the ``IMRA'' method (pulsed-field magnetization), and consequently a magnetic field of 1.59 T is generated at the center of 20 mm gap between the magnetic poles. As a result of experiment on the magnetic separation, hematite particles of over 90% were removed from slurry at the flow rate of 2 l/min.

Yokoyama, K.; Oka, T.; Okada, H.; Noto, K.

2003-10-01

9

High gradient magnetic separation using superconducting bulk magnets  

Energy Technology Data Exchange (ETDEWEB)

We aim to apply the superconducting bulk magnets to high gradient magnetic separation technique. Two bulk magnets are face-to-face arranged and a pipe stuffed magnetic filters composed of ferromagnetic wires is placed between the magnetic poles. We setup the magnetic separation system and test it using slurry mixed with hematite particles (Fe{sub 2}O{sub 3}). Y123 bulk superconductors are magnetized by the 'IMRA' method (pulsed-field magnetization), and consequently a magnetic field of 1.59 T is generated at the center of 20 mm gap between the magnetic poles. As a result of experiment on the magnetic separation, hematite particles of over 90% were removed from slurry at the flow rate of 2 l/min.

Yokoyama, K.; Oka, T.; Okada, H.; Noto, K

2003-10-15

10

Magnetic nanoparticles separation based on nanostructures  

International Nuclear Information System (INIS)

This study describes a magnetic array, which consists of depositing Fe nanowires on a porous alumina membrane. Such a device can be used as a planar magnetic separator. Its performance for the collection of Fe3O4 nanoparticles is experimentally shown. For magnetization of such iron nanowires in the vertical direction, we propose equations to calculate the theoretical absorption ratio.

2007-01-01

11

Desulphurisation of coal by magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

Pyrite and mineral matter in coal are very weakly paramagnetic and therefore have a very small positive magnetic susceptibility. The organic coal structure is diamagnetic, and possesses a negative magnetic susceptibility and is repelled from converging lines of flux in a magnetic field. Therefore, magnetic separation between these materials is possible theoretically. However, to capture a pyritic sulphur particle it is necessary to produce a strong field or high field gradient. 9 refs., 3 figs.

Rowson, N.A.; Rice, N.M.

1989-05-01

12

Evidence of phase separation in magnetic colloids using magnetic resonance  

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance of a surfacted magnetite-based magnetic fluid was investigated in a temperature range from 100 to 300 K. The magnetic resonance spectra were discussed in terms of contributions due to magnetic centers from isolated nanoparticles and dimers. The magnetic resonance data showed two distinct transitions. One due to a solid-liquid transition around 180 K for the colloid liquid carrier, whereas the second one near 240 K was attributed to phase separation. The spectra area analysis strongly supports our conclusions and additionally suggests the formation of agglomerates prior to the phase separation.

Skeff Neto, K. [Instituto de Fisica, Nucleo de Fisica Aplicada, Universidade de Brasilia, 70919-970, Brasilia-DF (Brazil)]. E-mail: kalilskeff@fis.unb.br; Bakuzis, A.F. [Instituto de Fisica, Nucleo de Fisica Aplicada, Universidade de Brasilia, 70919-970, Brasilia-DF (Brazil); Instituto de Fisica, Universidade Federal de Goias, 74001-970, Goiania-GO (Brazil); Goncalves, G.R.R. [Instituto de Fisica, Nucleo de Fisica Aplicada, Universidade de Brasilia, 70919-970, Brasilia-DF (Brazil); UniCEUB, Centro Universitario de Brasilia, FAET, 70790-075, Brasilia-DF (Brazil); Pelegrini, F. [Instituto de Fisica, Universidade Federal de Goias, 74001-970, Goiania-GO (Brazil); Morais, P.C. [Instituto de Fisica, Nucleo de Fisica Aplicada, Universidade de Brasilia, 70919-970, Brasilia-DF (Brazil)

2005-03-15

13

Magnetic nanoparticles separation based on nanostructures  

Energy Technology Data Exchange (ETDEWEB)

This study describes a magnetic array, which consists of depositing Fe nanowires on a porous alumina membrane. Such a device can be used as a planar magnetic separator. Its performance for the collection of Fe{sub 3}O{sub 4} nanoparticles is experimentally shown. For magnetization of such iron nanowires in the vertical direction, we propose equations to calculate the theoretical absorption ratio.

Sun Jianfei [State key Laboratory of BioElectronics, School of Biological Science and Medical Engineering, SouthEast University, Nanjing 210096 (China)]. E-mail: sunzaghi@seu.edu.cn; Xu Rui [Department of Physics, SouthEast University, Nanjing 210002 (China)]. E-mail: xurui04@mails.gscas.ac.cn; Zhang Yu [State key Laboratory of BioElectronics, School of Biological Science and Medical Engineering, SouthEast University, Nanjing 210096 (China); Ma Ming [State key Laboratory of BioElectronics, School of Biological Science and Medical Engineering, SouthEast University, Nanjing 210096 (China); Gu Ning [State key Laboratory of BioElectronics, School of Biological Science and Medical Engineering, SouthEast University, Nanjing 210096 (China)]. E-mail: guning@seu.edu.cn

2007-05-15

14

A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER  

Energy Technology Data Exchange (ETDEWEB)

A magnetic separator was designed to selectively separate fine-liberated magnetite. The conceptual design was simulated using CFD techniques. A separator tank was fabricated and a magnetic drum was used to capture magnetic particles. The initial tank design was modified to eliminate application oriented problems. The new separator was able to produce a fine product as a concentrate at relatively high feed rates. A plant simulation showed that such a device could lower circulating loads around ball mills by 16%, thereby creating room for a 5-8% increase in throughput at the same energy level. However, it was concluded that further improvements in terms of both size and mineral selectivity are needed to have a marketable product.

Salih Ersayin

2005-08-09

15

HTS High Gradient Magnetic Separation system  

Energy Technology Data Exchange (ETDEWEB)

We report on the assembly, characterization and operation of a high temperature superconducting (HTS) magnetic separator. The magnet is made of 624 m of Silver/BSCCO superconducting wire and has overall dimensions of 18 cm OD, 15.5 cm height and 5 cm ID. The HTS current leads are designed to operate with the warm end at 75 K and the cold end cooled by a two stage Gifford-McMahon cryocooler. The upper stage of the cryocooler cools the thermal shield and two heat pipe thermal intercepts. The lower stage of the cryocooler cools the HTS magnet and the bottom end of the HTS current leads. The HTS magnet was initially characterized in liquid cryogens. We report on the current- voltage (I-V) characteristics of the HTS magnet at temperatures ranging from 15 to 40 K. At 40 K the magnet can generate a central field of 2.0 T at a current of 120 A.

Daugherty, M.A.; Coulter, J.Y.; Hults, W.L. [and others

1996-09-01

16

Development of magnetic separation system of magnetoliposomes  

International Nuclear Information System (INIS)

[en] The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe3O4 of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe3O4 encapsulated with phospholipid liposomes of 200 nm in diameter was also shown to be trapped as external magnetic field of 1.5 T, but not of 0.5 T. We also showed the result of particle trajectory calculation which emulated well the experimental data.

2009-10-15

17

Development of magnetic separation system of magnetoliposomes  

Energy Technology Data Exchange (ETDEWEB)

The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe{sub 3}O{sub 4} of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe{sub 3}O{sub 4} encapsulated with phospholipid liposomes of 200 nm in diameter was also shown to be trapped as external magnetic field of 1.5 T, but not of 0.5 T. We also showed the result of particle trajectory calculation which emulated well the experimental data.

Nakao, R., E-mail: ryo-nakao@see.qb.eng.osaka-u.ac.j [Osaka University. Yamadaoka 2-1, Suita, Osaka, 565-0871 (Japan); Matuo, Y.; Mishima, F. [Osaka University. Yamadaoka 2-1, Suita, Osaka, 565-0871 (Japan); Taguchi, T. [Osaka University. Yamadaoka 2-1, Suita, Osaka, 565-0871 (Japan); University of Queensland, 4072, QLD (Australia); Maenosono, S. [Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292 (Japan); Nishijima, S. [Osaka University. Yamadaoka 2-1, Suita, Osaka, 565-0871 (Japan)

2009-10-15

18

Development of magnetic separation system of magnetoliposomes  

Science.gov (United States)

The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe3O4 of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe3O4 encapsulated with phospholipid liposomes of 200 nm in diameter was also shown to be trapped as external magnetic field of 1.5 T, but not of 0.5 T. We also showed the result of particle trajectory calculation which emulated well the experimental data.

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

2009-10-01

19

MAGNETIC SEPARATION FOR SILICON-CONTAINING MATERIALS  

UK PubMed Central (United Kingdom)

Magnetic separators are used for treating silicon-containing materials from chlorosilane reactors to remove magnetically influenced components in the silicon-containing materials. The removal of such impurities allows for enhanced reactivity of the silicon-containing materials in processes wherein the silicon-containing materials are raw materials for the production of silicon based compounds, such as, for example, basic alkylhalosilanes such as dimethyldichlorosilane, methyldichlorosilane, and other chlorosilanes such as trichlorosilane, which chlorosilanes are useful in the preparation of valuable silicon-containing products.

HERMAN JOHN ERIC; BRINSON JONATHAN ASHLEY; SNODGRASS DAVID WILLIAM; HOSOKAWA HIDEHIKO

20

Optimization of the geometry of open gradient magnetic separators  

Energy Technology Data Exchange (ETDEWEB)

Calculations have been done to obtain expressions for the optimal geometrical parameter of the magnetic system in an open gradient magnetic separator. A magnetic separator consisting of disk-shaped coils which have a common axis of symmetry and have a canister located inside the coils has been used for the calculations of magnetic system geometry and separator efficiency. (AIP)

Piskunov, A.N.; Fedorov, V.K.; Cheremnykh, P.A.

1983-02-01

 
 
 
 
21

Magnetic force on a magnetic particle within a high gradient magnetic separator  

Science.gov (United States)

HGMS (High Gradient Magnetic Separator) uses matrix to make high magnetic field gradient so that ferro- or para-magnetic particles can be attracted to them by high magnetic force. The magnetic force generated by the field gradient is several thousand times larger than that by background magnetic field alone. So the HGMS shows excellent performance compared with other magnetic separators. These matrixes are usually composed of stainless steel wires having high magnetization characteristics. This paper deals with superconducting HGMS which is aimed for purifying waste water by using stainless steel matrix. Background magnetic field up to 6 T is generated by a superconducting solenoid and the stainless steel matrixes are arranged inside of the solenoid. Based on magnetic field calculated by FEM (Finite Element Method), we could calculate magnetic force acting on a magnetic particle such as hematite and maghemite consisting of major impurities in the condenser water of a thermal power station.

Baik, S. K.; Ha, D. W.; Kwon, J. M.; Lee, Y. J.; Ko, R. K.

2013-01-01

22

Separation of bubbles from solid surfaces in magnetic fluids  

Energy Technology Data Exchange (ETDEWEB)

Experimental investigation of air bubbles separation in magnetic fluid from the solid surfaces with the presence of uniform and non-uniform magnetic fields is presented in this work. The critical volumes of the bubbles and the dependences on magnetic field are ascertained. The strong influence of non-uniform magnetic field on bubble separation from the solid plate is observed.

Bashtovoi, V. [UNESCO Chair, Belarussian National Technical University, 65 F.Skaryina Ave., Minsk, 220013 (Belarus); Kovalev, M. [UNESCO Chair, Belarussian National Technical University, 65 F.Skaryina Ave., Minsk, 220013 (Belarus); Reks, A. [UNESCO Chair, Belarussian National Technical University, 65 F.Skaryina Ave., Minsk, 220013 (Belarus)]. E-mail: agreks@tut.by

2005-03-15

23

Wet high-intensity magnetic separation  

International Nuclear Information System (INIS)

Miscellaneous laboratory tests (most of them on cyanide residues) were undertaken to supplement on-site pilot-plant work on wet high intensity magnetic separation (WHIMS). Initially, the main concern was with blockage of the matrix, and consideration was given to the use of a reverse-flushing system. The laboratory tests on this system were encouraging, but they were not of sufficiently long duration to be conclusive. The velocity of the pulp through the matrix is important, because it determines the capacity of the separator and the recovery obtainable. Of almost equal importance is the magnetic load, which affects the velocity of the pulp and the recovery. Typically, a recovery of 51 per cent of the uranium was reduced to one of 40 per cent as the magnetic load was increased from 25 to 100 g/l, while the pulp velocity decreased from 62 to 36 mm/s. There was some indication that, for the same pulp velocity, lower recoveries are obtained when free-fall feeding is used. Some benefit was observed in the application of WHIMS to coarsely ground ore; from a Blyvooruitzicht rod-mill product, 25 per cent of the total uranium was recovered when only 29 per cent of the rod-mill product (the finest portion) was treated. A similar recovery was made from 43 per cent of the rod-mill product from Stilfontein; a second stage of treatment after regrinding raised the overall recovery of uranium to 76,4 per cent. Recoveries of 55 and 42 per cent of the uranium were obtained in tests on two flotation tailings from Free State Geduld. In a determination of the mass magnetic susceptibilities of the constituents in a typical concentrate obtained by WHIMS, it was found that some 20 per cent of the magnetic product had a susceptibility of less than 5,4 X 10-6 e.m.u. but contained 38 per cent of the uranium recovered by WHIMS. A few tests were conducted on different types of matrix. A matrix of spaced horizontal rods is recommended for possible future consideration.

1980-01-01

24

Magnetic separation technique for environmental water purification by strong magnetic field generator loading HTS bulk magnets  

International Nuclear Information System (INIS)

The magnetic separation technique in combination with high temperature superconducting bulk magnets has been investigated to purify the ground water which has been used in the coolant system for the incinerator furnace to cool the burning gas. The experiment has been operated by means of the newly-built alternating channel type magnetic separating device. The separation ratios of ferromagnetic flocks including fine magnetite powder have been estimated by means of the high gradient magnetic separation method with small iron balls filled in the water channels. As the magnetic force acting on the magnetic particle is given by the product of a magnetization of the material and a gradient of magnetic field, and as the ferromagnetic stainless steel balls yield the steep gradient of magnetic field around them in a strong magnetic field, the system has exhibited a quite excellent performance with respect to the separation ratios. The separation ratios of the flocks which contain the magnetite powder with the values more than 50 ppm have remained over 80% for under the flow rates less than 5 L/min.

2010-11-01

25

MSWI boiler fly ashes: magnetic separation for material recovery.  

Science.gov (United States)

Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments. PMID:21306886

De Boom, Aurore; Degrez, Marc; Hubaux, Paul; Lucion, Christian

2011-02-08

26

MSWI boiler fly ashes: magnetic separation for material recovery.  

UK PubMed Central (United Kingdom)

Nowadays, ferrous materials are usually recovered from Municipal Solid Waste Incineration (MSWI) bottom ash by magnetic separation. To our knowledge, such a physical technique has not been applied so far to other MSWI residues. This study focuses thus on the applicability of magnetic separation on boiler fly ashes (BFA). Different types of magnet are used to extract the magnetic particles. We investigate the magnetic particle composition, as well as their leaching behaviour (EN 12457-1 leaching test). The magnetic particles present higher Cr, Fe, Mn and Ni concentration than the non-magnetic (NM) fraction. Magnetic separation does not improve the leachability of the NM fraction. To approximate industrial conditions, magnetic separation is also applied to BFA mixed with water by using a pilot. BFA magnetic separation is economically evaluated. This study globally shows that it is possible to extract some magnetic particles from MSWI boiler fly ashes. However, the magnetic particles only represent from 23 to 120 g/kg of the BFA and, though they are enriched in Fe, are composed of similar elements to the raw ashes. The industrial application of magnetic separation would only be profitable if large amounts of ashes were treated (more than 15 kt/y), and the process should be ideally completed by other recovery methods or advanced treatments.

De Boom A; Degrez M; Hubaux P; Lucion C

2011-07-01

27

Secondary particle magnetic achromatic separator for the IAEh cyclotron  

International Nuclear Information System (INIS)

[en] A magnetic achromatic separator of exotic nuclei is designed for cyclotron experiments with recording particles emerging from the target at small angles (including that of 0 deg) as well as for separation and use of radioactive nuclei, such as 6He, 8He, 7Be. The ion-optic system of the separator is a symmetric magnetic achromatic consisting of two dipole magnets with the homogeneous field and beveled edges, two doublets and one singlet of quadrupole magnets. The separator characteristics, design and possible applications are presented. 15 refs.; 12 figs

1989-01-01

28

Magnetic separation for rare earth oxide recovery at Sillamaee, Estonia  

International Nuclear Information System (INIS)

Magnetic separation can be used to concentrate rare earth oxides or actinides from extraneous materials yielding more efficient recovery and treatment operations. The authors anticipate that with proper pretreatment, mainly consisting of size reduction, a permanent magnet roll separator will be the method of choice for recovery of rare-earth oxides

2000-01-01

29

Magnetic separation of micro-spheres from viscous biological fluids.  

UK PubMed Central (United Kingdom)

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 MD; Caviness PL; Liu X; Dhar P; Torno M; Rosengart AJ

2007-02-01

30

Magnetic separation of coal fly ash from Bulgarian power plants.  

UK PubMed Central (United Kingdom)

Fly ash from three coal-burning power plants in Bulgaria: 'Maritza 3', 'Republika' and 'Rousse East' were subjected to wet low-intensity magnetic separation. The tests were performed at different combinations of magnetic field intensity, flow velocity and diameter of matrix elements. It was found that all parameters investigated affected the separation efficiency, but their influence was interlinked and was determined by the properties of the material and the combination of other conditions. Among the fly ash characteristics, the most important parameters, determining the magnetic separation applicability, were mineralogical composition and distribution of minerals in particles. The main factors limiting the process were the presence of paramagnetic Fe-containing mineral and amorphous matter, and the existence of poly-mineral particles and aggregates of magnetic and non-magnetic particles. It was demonstrated that the negative effect of both factors could be considerably limited by the selection of a proper set of separation conditions. The dependences between concentration of ferromagnetic iron in the ash, their magnetic properties and magnetic fraction yields were studied. It was experimentally proved that, for a certain set of separation conditions, the yields of magnetic fractions were directly proportional to the saturation magnetization of the ferromagnetic components of the ash. The main properties of typical magnetic and non-magnetic fractions were studied.

Shoumkova AS

2011-10-01

31

Magnetic field trimming studies for a separated-sector cyclotron  

International Nuclear Information System (INIS)

[en] Magnetic field studies were made for a four-sector, K = 330 (E = Kq2/A MeV), separated-sector cyclotron using a 1/10 scale model of a single sector equipped with 11 trimming coils. Data are presented showing the effects of saturation at high magnetic fields on the field contour and on the trimming coil characteristics. Some implications of these measurements for the design of separated-sector machine magnets are given. (U.S.)

1975-08-19

32

Magnetically separable composite photocatalyst with enhanced photocatalytic activity.  

UK PubMed Central (United Kingdom)

A novel magnetically separable composite photocatalyst, anatase titania-coated magnetic activated carbon (TMAC), was prepared in this article. In the synthesis, magnetic activated carbon (MAC) was firstly obtained by adsorbing magnetic Fe3O4 nanoparticles onto the activated carbon (AC), and then the obtained MAC was directly coated by anatase titania nanoparticles prepared at low temperature (i.e. 75 degrees C). The prepared samples were characterized by XRD, SEM and vibrating sample magnetometer (VSM). The composite photocatalyst can be easily separated from solution by a magnet, its photocatalytic activity in degradation of phenol in aqueous solution also has dramatic enhancement compared to that of the neat titania.

Ao Y; Xu J; Shen X; Fu D; Yuan C

2008-12-01

33

Magnetically separable composite photocatalyst with enhanced photocatalytic activity.  

Science.gov (United States)

A novel magnetically separable composite photocatalyst, anatase titania-coated magnetic activated carbon (TMAC), was prepared in this article. In the synthesis, magnetic activated carbon (MAC) was firstly obtained by adsorbing magnetic Fe3O4 nanoparticles onto the activated carbon (AC), and then the obtained MAC was directly coated by anatase titania nanoparticles prepared at low temperature (i.e. 75 degrees C). The prepared samples were characterized by XRD, SEM and vibrating sample magnetometer (VSM). The composite photocatalyst can be easily separated from solution by a magnet, its photocatalytic activity in degradation of phenol in aqueous solution also has dramatic enhancement compared to that of the neat titania. PMID:18406055

Ao, Yanhui; Xu, Jingjing; Shen, Xunwei; Fu, Degang; Yuan, Chunwei

2008-03-08

34

Feasibility study of iron mineral separation from red mud by high gradient superconducting magnetic separation  

International Nuclear Information System (INIS)

Research highlights: ? Red mud residues (RM) were disposed in alumina production. ? Utilization of Red mud residues was affected by its iron content. ? Superconducting magnetic separation (HGSMS) was used in iron separation from RM. ? RM with high and low iron contents were separated in HGSMS. - Abstract: The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (

2011-01-01

35

A High-Throughput SU-8Microfluidic Magnetic Bead Separator  

DEFF Research Database (Denmark)

We present a novel microfluidic magnetic bead separator based on SU-8 fabrication technique for high through-put applications. The experimental results show that magnetic beads can be captured at an efficiency of 91 % and 54 % at flow rates of 1 mL/min and 4 mL/min, respectively. Integration of soft magnetic elements in the chip leads to a slightly higher capturing efficiency and a more uniform distribution of captured beads over the separation chamber than the system without soft magnetic elements.

Bu, Minqiang; Christensen, T. B.

2007-01-01

36

Microstripes for transport and separation of magnetic particles  

Science.gov (United States)

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.

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

2012-01-01

37

Application of HTS bulk magnet system to the magnetic separation techniques for water purification  

International Nuclear Information System (INIS)

We have investigated the application of the HTS bulk magnets to the magnetic separation techniques for the waste water drained from the university laboratories. The study has been conducted in comparison with the electromagnets, and the cryo-cooled superconducting solenoid magnet. A superconducting bulk magnet has the highest value of the trapped magnetic fields at the centre of the sample surface, showing a sharp gradient of the magnetic field on the surface. Magnetic force acting on magnetic particles in magnetic fields is given by the product of a magnetization of particles and a gradient of magnetic field. The HTS bulk is superior to a solenoid magnet which has a poor gradient in magnetic fields in a bore. The separation ratios of ferrite precipitates in the waste slurry were estimated by means of the high gradient magnetic separation method which requires iron filters in the water channel and open gradient magnetic separation without any filters. The magnetic separation using HTS bulk magnet is substantially effective for the practical water purification.

2008-09-15

38

Magnetically activated micromixers for separation membranes.  

UK PubMed Central (United Kingdom)

Presented here is a radically novel approach to reduce concentration polarization and, potentially, also fouling by colloids present in aqueous feeds: magnetically responsive micromixing membranes. Hydrophilic polymer chains, poly(2-hydroxyethyl methacrylate) (PHEMA), were grafted via controlled surface-initiated atom transfer radical polymerization (SI-ATRP) on the surface of polyamide composite nanofiltration (NF) membranes and then end-capped with superparamagnetic iron oxide magnetite (Fe(3)O(4)) nanoparticles. The results of all functionalization steps, that is, bromide ATRP initiator immobilization, SI-ATRP, conversion of PHEMA end groups from bromide to amine, and carboxyl-functional Fe(3)O(4) nanoparticle immobilization via peptide coupling, have been confirmed by X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). These nanoparticles experience a magnetic force as well as a torque under an oscillating external magnetic field. It has been shown, using particle image velocimetry (PIV), that the resulting movement of the polymer brushes at certain magnetic field frequencies induces mixing directly above the membrane surface. Furthermore, it was demonstrated that with such membranes the NF performance could significantly be improved (increase of flux and salt rejection) by an oscillating magnetic field, which can be explained by a reduced concentration polarization in the boundary layer. However, the proof-of-concept presented here for the active alteration of macroscopic flow via surface-anchored micromixers based on polymer-nanoparticle conjugates has much broader implications.

Himstedt HH; Yang Q; Dasi LP; Qian X; Wickramasinghe SR; Ulbricht M

2011-05-01

39

Study on magnetic separation system using high Tc superconducting bulk magnets for water purification technique  

International Nuclear Information System (INIS)

The application of superconducting bulk magnets to the magnetic separation techniques has been investigated for the Mn-bearing waste water drained from the university laboratories. The research has been conducted in comparison with the electromagnets, and the cryo-cooled superconducting solenoid magnet. The separation ratios of ferrite precipitates including Mn element in the waste slurry were estimated by means of the high gradient magnetic separation method with ferromagnetic iron filters in the water channel and open gradient magnetic separation without them. As the magnetic force acting on the particles is given by the product of a magnetization of particles and a gradient of magnetic field, and a superconducting bulk magnet shows a sharp gradient of the magnetic field on the surface, the performances of the bulk magnet system were almost equivalent to those of the superconducting solenoid magnet with wide bore with respect to the magnetic separation ratios. The separation ratios for Mn have reached over 80 % for HGMS and 10 % for OGMS under the flow rates less than 3 liter/min.

2009-03-01

40

In Situ Magnetic Separation for Extracellular Protein Production  

DEFF Research Database (Denmark)

A new approach for in situ product removal from bioreactors is presented in which high-gradient magnetic separation is used. This separation process was used for the adsorptive removal of proteases secreted by Bacillus licheniformis. Small, non-porous bacitracin linked magnetic adsorbents were employed directly in the broth during the fermentation, followed by in situ magnetic separation, Proof of the concept was first demonstrated in shake flask culture, then scaled up and applied during a fed batch cultivation ill a 3.7 L bioreactor. It could be demonstrated that growth of B. licheniformis was not influenced by the in situ product removal step. Protease production also remained the same after the separation step. Furthermore, degradation of the protease, which followed first order kinetics, was reduced by using the method. Using a theoretical modeling approach, we Could show that protease yield in total was enhanced by using in situ magnetic separation. The process described here is a promising technique toimprove overall yield in No production processes which are often limited due to weak downstream operations, Potential limitations encountered during a bioprocess can be overcome such as product inhibition or degradation. We also discuss the key points where research is needed to implement in situ magnetic separation in industrial production.

Kappler, T.; Cerff, Martin

2009-01-01

 
 
 
 
41

Low field orientation magnetic separation methods for magnetotactic bacteria  

Energy Technology Data Exchange (ETDEWEB)

Microbial biomineralisation of iron often results in a biomass that is magnetic and can be separated from water systems by the application of a magnetic field. Magnetotactic bacteria form magnetic membrane bound crystals within their structure, generally of magnetite. In nature, this enables magnetotactic bacteria to orientate themselves with respect to the local geomagnetic field. The bacteria then migrate with flagellar driven motion towards their preferred environment. This property has been harnessed to produce a process in which metal loaded magnetotactic bacteria can be recovered from a waste stream. This process is known as orientation magnetic separation. Several methods exist which permit the unique magnetic properties of individual magnetotactic bacteria to be studied, such as U-turn analysis, transmission electron microscopy and single wire cell studies. In this work an extension of U-turn analysis was developed. The bacteria were rendered non-motile by the addition of specific metal ions and the resulting 'flip time' which occurs during a field reversal enabled the magnetic moment of individual bacteria to be determined.This method proved to be much faster and more accurate than previous methods. For a successful process to be developed, large scale culturing of magnetotactic bacteria is required Experiments showed that culture vessel geometry was an important factor for high-density growth. Despite intensive studies reproducible culturing at volumes exceeding one litre was not achieved. This work showed that numerous metal ions rendered magnetotactic bacteria non-motile at concentrations below 10 ppm. Sequential adaptation raised typical levels to in excess of 100 ppm for a number of ions. such as zinc and tin. However, specific ions. such as copper or nickel, remained motility inhibiting at lower concentrations. To achieve separation using orientation magnetic separation, motile, field susceptible MTB are required. Despite successful adaptation, the range of motility inhibiting ions is such that MTB cannot be envisaged for general wastewater applications. Radionucleide studies were undertaken targeting a niche application where this metal ion restriction would not apply. Liquid scintillation and {gamma}-ray counting measurements indicated that magnetotactic bacteria accumulate high levels of both plutonium and mercury. A number of both static and flow recovery separators for magnetotactic bacteria were developed. Statistical models predicting the behaviour of these separators were compared to measured results. These comparisons highlighted the problems of 'wash off' of accumulated bacteria in separators where flow was present. The most successful of the flow recovery designs - the channel separator - was then tested using a simulated effluent that contained plutonium. The results confirmed both previous radioisotope uptake studies and separator test results. The channel separator design was enhanced by the introduction of wire arrays into the separation chamber. Orientation magnetic separation in these hybrid-type separators was used to accumulate the biomass and the magnetic gradients generated by the wire arrays to retain the bacteria on the separator walls. These separators achieved increases in efficiency of up to 300% compared with the channel separator. In summary, this thesis describes a successful separation process for the recovery of motile MTB. However, to apply this separator approach to the suggested radioisotope application would require successful large scale culturing. (author)

Moeschler, F.D

1999-07-01

42

Low field orientation magnetic separation methods for magnetotactic bacteria  

International Nuclear Information System (INIS)

Microbial biomineralisation of iron often results in a biomass that is magnetic and can be separated from water systems by the application of a magnetic field. Magnetotactic bacteria form magnetic membrane bound crystals within their structure, generally of magnetite. In nature, this enables magnetotactic bacteria to orientate themselves with respect to the local geomagnetic field. The bacteria then migrate with flagellar driven motion towards their preferred environment. This property has been harnessed to produce a process in which metal loaded magnetotactic bacteria can be recovered from a waste stream. This process is known as orientation magnetic separation. Several methods exist which permit the unique magnetic properties of individual magnetotactic bacteria to be studied, such as U-turn analysis, transmission electron microscopy and single wire cell studies. In this work an extension of U-turn analysis was developed. The bacteria were rendered non-motile by the addition of specific metal ions and the resulting 'flip time' which occurs during a field reversal enabled the magnetic moment of individual bacteria to be determined. This method proved to be much faster and more accurate than previous methods. For a successful process to be developed, large scale culturing of magnetotactic bacteria is required Experiments showed that culture vessel geometry was an important factor for high-density growth. Despite intensive studies reproducible culturing at volumes exceeding one litre was not achieved. This work showed that numerous metal ions rendered magnetotactic bacteria non-motile at concentrations below 10 ppm. Sequential adaptation raised typical levels to in excess of 100 ppm for a number of ions. such as zinc and tin. However, specific ions. such as copper or nickel, remained motility inhibiting at lower concentrations. To achieve separation using orientation magnetic separation, motile, field susceptible MTB are required. Despite successful adaptation, the range of motility inhibiting ions is such that MTB cannot be envisaged for general wastewater applications. Radionucleide studies were undertaken targeting a niche application where this metal ion restriction would not apply. Liquid scintillation and ?-ray counting measurements indicated that magnetotactic bacteria accumulate high levels of both plutonium and mercury. A number of both static and flow recovery separators for magnetotactic bacteria were developed. Statistical models predicting the behaviour of these separators were compared to measured results. These comparisons highlighted the problems of 'wash off' of accumulated bacteria in separators where flow was present. The most successful of the flow recovery designs - the channel separator - was then tested using a simulated effluent that contained plutonium. The results confirmed both previous radioisotope uptake studies and separator test results. The channel separator design was enhanced by the introduction of wire arrays into the separation chamber. Orientation magnetic separation in these hybrid-type separators was used to accumulate the biomass and the magnetic gradients generated by the wire arrays to retain the bacteria on the separator walls. These separators achieved increases in efficiency of up to 300% compared with the channel separator. In summary, this thesis describes a successful separation process for the recovery of motile MTB. However, to apply this separator approach to the suggested radioisotope application would require successful large scale culturing. (author)

1999-01-01

43

Magnetic sensor particles: an optimized magnetic separator with an optical window  

International Nuclear Information System (INIS)

[en] Magnetically separable optical sensor particles represent a good alternative for conventional electrochemical and fibre-optical oxygen and pH sensors. Further improving the suitability of magnetically separable optical sensor particles, we reconstructed the separation adapters. Computer simulations of magnetic fields indicated that an assembly of radially magnetized rings is preferred. We investigated different materials and dimensions of adapters and improved commercially available, axially magnetized rings using a magnetically soft iron cone together with the rings. Adapters simulating a radially magnetized ring were constructed out of several block magnets arranged like a star around an optical fibre. These adapters collected the sensor particles exactly in the field of view ensuring high efficiency and, on top of that, showed a higher resistance of the resulting sensor spot against shear forces in stirred liquid. All adapters were characterized in a stirred flask recording signal intensity versus stirrer speed plots

2008-04-21

44

Possibilities and prospects for using high-gradient magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The principles of high-gradient magnetic separation using simple mathematical models and the operation of high-gradient magnetic separators in basic terms are described. The main characteristics and design principles of various types of separators are discussed, categorizing them into first generation (Jones, Boxmag-Rapid, Readings, Kruppsol, MRVK) and second generation (Kolm-Marston, Sala, PEM, VMS). The extent to which separators are currently in use is discussed: in Czechoslovakia MRVKs were used until recently when the VMS-50 and VMS-100 were developed; the VMS-100 has a capacity of 100 t/h, water consumption of 1.4 m/sup 3//t, energy consumption of 0.7 kWh/t, weight 120 t and price 12.8 million Czechoslovak Crowns. Feasibility is discussed for using HGMS in Czechoslovak conditions, where it is used for: preparation of ferrous and nonferrous metals, radioactive materials, ceramics, waste water and coal. The paper states that magnetic separation can be used for removing inorganic sulfur from the coal mass in power plants, thus preventing atmospheric pollution, but up to now dry magnetic separation of ungraded coal has given poor results. However, further detailed research should be capable of finding a way to make this method suitable for coal preparation in Czechoslovakia. 56 references.

Hencl, V.

1986-04-01

45

Dendrimer-coated magnetic particles for radionuclide separation  

International Nuclear Information System (INIS)

Magnetic particles were synthesised for radionuclide removal from nuclear wastes by magnetic separation. Dendrimers with terminal amino groups attached to the particle surface were used to bind chelating groups for lanthanides and actinides. This led to a 50-400-fold increase of the distribution coefficients for europium and americium in comparison to the reference particles without the dendrimers. Back-extraction studies have demonstrated the possibility of multiple particle recycling.

2005-01-01

46

Silica coated magnetic nanoparticles for separation of nuclear acidic waste  

International Nuclear Information System (INIS)

[en] Fe2O3 magnetic nanoparticles (MNPs) have been coated with silica, followed by covalent attachment of the actinide specific chelators to separate nuclear waste in acidic conditions. A general model is developed to relate the surface coating to the particle's magnetization change, providing an alternative way to characterize the size-distribution/aggregation of MNPs. The optimized silica coating protects the Fe2O3 MNPs from iron leaching under highly acidic conditions, facilitates the dispersion of MNPs, and dramatically increases the loading capacity of chelator onto the MNPs. Compared with the uncoated counterparts, the silica coated MNPs show enhanced actinide separation efficiency.

2010-01-01

47

Separation of actinide-made transurania by a gas-filled magnetic separator  

International Nuclear Information System (INIS)

The performance of the gas-filled magnetic separator HECK at the UNI-LAC at GSI Darmstadt is described. The system consists of a 30 -dipole magnet and a quadrupole doublet of wide aperture. The separator is operated with helium at pressures between (0.1-1) hPa. It is used to investigate heavy ion induced fusion products in-flight. The recoils emerging from a thin target are separated with high efficiency of (10-50)%. The suppression factor of primary beam particles and transfer products is (1015) and (103), respectively. In this application of a gas-filled separator to synthesize transuranium elements using 238U-targets, isotopes of the elements fermium and nobelium were identified in irradiations with 16O- and 20Ne-beams. (orig.)

1994-01-01

48

Preparation of silanized magnetic nanoparticles for magnetic separation technique use  

International Nuclear Information System (INIS)

[en] Superparamagnetic particles of magnetite were functionalized with 3-aminopropyltriethoxysilane by direct silanization to provide the modified magnetic nanoparticles. They are characterized by scanning and transmission electron microscopy, infrared absorption spectroscopy and by the thermogravimetry. The characterizations by infrared absorption spectroscopy and thermogravimetry confirmed the functionalization. The adsorption capacity of the silanized magnetite and equilibrium isotherm of Eu (III) ions from nitric solution were determined. (author)

2002-01-01

49

Separation of the Magnetic Field into External and Internal Parts  

DEFF Research Database (Denmark)

The magnetic field of a planet or a planetary moon contains contributions from a variety of sources in the environment of the body (external sources) and its interior (internal sources). This chapter describes different methods that have been developed for the separation of external and internal source contributions, and their application to selected planets and one of Jupiter’s moons, Ganymede.

Olsen, Nils; Glassmeier, K.-H.

2010-01-01

50

Magnetic separation as a plutonium residue enrichment process  

Energy Technology Data Exchange (ETDEWEB)

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

51

Magnetic Separations with Magnetite: Theory, Operation, and Limitations  

Energy Technology Data Exchange (ETDEWEB)

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

52

Magnetic Separations with Magnetite: Theory, Operation, and Limitations  

International Nuclear Information System (INIS)

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.

2000-01-01

53

Magnetic separation using high-T sub c superconductors  

CERN Multimedia

sensitivity of the high-T sub c material to magnetic fields. Finite elements modelling of the system has provided the framework for the quantitative analysis of the magnetic field distributions on the coil windings and the optimisation of the system configuration. The performance of the separator has been tested at 77 K with liquid nitrogen at atmospheric pressure, and at a temperature approx = 67 K by pumping liquid nitrogen at a pressure around 100 Torr. The highest field obtained in the air gap at 67 K was of 340 mT. Magnetic separators with an iron circuit have been in operation for many years in mineral industry, and there appear to be an opportunity of building machines with high-T sub c coils or retrofitting existing machines with high-T sub c coils to run them closer to saturation in a cheap and effective way. Superconductivity has found in magnetic separation one of its major industrial applications second only to magnetic resonance imaging. Low-T sub c superconducting coils have been employed in Hig...

Bolt, L

2001-01-01

54

Magnetic precipitate separation for Ni plating waste liquid using HTS bulk magnets  

Science.gov (United States)

The magnetic separation experiment for recycling the nickel-bearing precipitates in the waste liquid from the electroless plating processes has been practically conducted under the high gradient magnetic separation technique with use of the face-to-face HTS bulk magnet system. A couple of facing magnetic poles containing Sm123 bulk superconductors were activated through the pulsed field magnetization process to 1.86 T at 38 K and 2.00 T at 37 K, respectively. The weakly magnetized metallic precipitates of Ni crystals and Ni-P compounds deposited from the waste solution after heating it and pH controlling. The high gradient magnetic separation technique was employed with the separation channels filled with the stainless steel balls with dimension of 1 and 3 mm in diameter, which periodically moved between and out of the facing magnetic poles. The Ni-bearing precipitates were effectively attracted to the magnetized ferromagnetic balls. We have succeeded in obtaining the separation ratios over 90% under the flow rates less than 1.35 L/min.

Oka, T.; Kimura, T.; Mimura, D.; Fukazawa, H.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M.; Yokoyama, K.; Tsujimura, M.; Terasawa, T.

2013-01-01

55

Feasibility study of iron mineral separation from red mud by high gradient superconducting magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Red mud residues (RM) were disposed in alumina production. {yields} Utilization of Red mud residues was affected by its iron content. {yields} Superconducting magnetic separation (HGSMS) was used in iron separation from RM. {yields} RM with high and low iron contents were separated in HGSMS. - Abstract: The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (<100 {mu}m) into high iron content part and low iron content part. Two sorts of RM were fed in the HGSMS. The iron oxide contents in concentrates were about 65% and 45% when RM 1 and RM 2 were fed respectively. Meanwhile, the residues contained 52.0% or 14.1% iron oxide in residues after eight separation stages when RM 1 and RM 2 were fed respectively. The mass recovery of iron concentrates was about 10% after once separation process regardless of RM 1 or RM 2 was fed. Extreme fine particles (<10 {mu}m) could be captured in the HGSMS. Intergrowth of Fe and other elements is disadvantages for iron mineral separation from RM by HGSMS. Some improvement should be studied to enhance the efficiency of iron separation. It is possible for HGSMS to separate RM into high iron content part and low iron content part, the former part could be used in iron-making furnace and the later part could be recycling to sintering process for alumina production or used as construction material.

Li Yiran, E-mail: lyr2006xd@yahoo.com.c [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Jun, E-mail: junwang@rcees.ac.c [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Xiaojun; Wang Baoqiang; Luan Zhaokun [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)

2011-02-15

56

Waste water purification by magnetic separation technique using HTS bulk magnet system  

International Nuclear Information System (INIS)

We have investigated the feasibility of strong magnetic field generators composed of the high temperature superconducting (HTS) bulk magnet systems to the magnetic separation techniques for the waste water including thin emulsion bearing the cutting oil. Two types of the strong field generators were prepared by the face-to-face HTS bulk magnet systems, which emit the magnetic field density of 1 and 2 T in the open spaces between the magnetic poles activated by the pulsed field magnetization and the field cooling methods, respectively. A couple of water channels containing iron balls were settled in the strong field to trap the magnetized flocks in the waste water. The separation ratios of flocks containing 200 ppm magnetite powder were evaluated with respect to the flow rates of the waste water. The performances of bulk magnet system have kept showing values of around 100% until the flowing rate reached up to 18 l/min. This suggests that the magnetic separation by using bulk magnets is effective for the practical water purification systems.

2009-10-15

57

Endotoxin removal by magnetic separation-based blood purification.  

UK PubMed Central (United Kingdom)

This work describes a magnetic separation-based approach using polymyxin B-functionalized metal alloy nanomagnets for the rapid elimination of endotoxins from human blood in vitro and functional assays to evaluate the biological relevance of the blood purification process. Playing a central role in gram-negative sepsis, bacteria-derived endotoxins are attractive therapeutic targets. However, both direct endotoxin detection in and removal from protein-rich fluids remains challenging. We present the synthesis and functionalization of ultra-magnetic cobalt/iron alloy nanoparticles and a magnetic separation-based approach using polymyxin B-functionalized nanomagnets to remove endotoxin from human blood in vitro. Conventional chromogenic Limulus Amebocyte Lysate assays confirm decreased endotoxin activity in purified compared to untreated samples. Functional assays assessing key steps in host defense against bacteria show an attenuated inflammatory mediator expression from human primary endothelial cells in response to purified blood samples compared to untreated blood and less chemotactic activity. Exposing Escherichia coli-positive blood samples to polymyxin B-functionalized nanomagnets even impairs the ability of gram-negative bacteria to form colony forming units, thus making magnetic separation based blood purification a promising new approach for future sepsis treatment.

Herrmann IK; Urner M; Graf S; Schumacher CM; Roth-Z'graggen B; Hasler M; Stark WJ; Beck-Schimmer B

2013-06-01

58

Endotoxin removal by magnetic separation-based blood purification.  

Science.gov (United States)

This work describes a magnetic separation-based approach using polymyxin B-functionalized metal alloy nanomagnets for the rapid elimination of endotoxins from human blood in vitro and functional assays to evaluate the biological relevance of the blood purification process. Playing a central role in gram-negative sepsis, bacteria-derived endotoxins are attractive therapeutic targets. However, both direct endotoxin detection in and removal from protein-rich fluids remains challenging. We present the synthesis and functionalization of ultra-magnetic cobalt/iron alloy nanoparticles and a magnetic separation-based approach using polymyxin B-functionalized nanomagnets to remove endotoxin from human blood in vitro. Conventional chromogenic Limulus Amebocyte Lysate assays confirm decreased endotoxin activity in purified compared to untreated samples. Functional assays assessing key steps in host defense against bacteria show an attenuated inflammatory mediator expression from human primary endothelial cells in response to purified blood samples compared to untreated blood and less chemotactic activity. Exposing Escherichia coli-positive blood samples to polymyxin B-functionalized nanomagnets even impairs the ability of gram-negative bacteria to form colony forming units, thus making magnetic separation based blood purification a promising new approach for future sepsis treatment. PMID:23225582

Herrmann, Inge K; Urner, Martin; Graf, Samuel; Schumacher, Christoph M; Roth-Z'graggen, Birgit; Hasler, Melanie; Stark, Wendelin J; Beck-Schimmer, Beatrice

2012-12-06

59

Separation of impurity in molten metals by using superconducting magnet  

International Nuclear Information System (INIS)

[en] The separation method by using electromagnetic force is receiving particular attention as elimination method of impurities in molten metal. In this study, low-melting metal is used as model metal and the relation between electromagnetic force and motion of the particle in molten metal was discussed by calculation and experiment. As the result of calculation, the relation between electromagnetic force and separation efficiency can be obtained. The electromagnetic separation was experimented in the condition that was estimated from the results of calculation (average flow velocity: 0.4 m/s, magnetic flux density: 10 T, electric current density: 3.3E+4 A/m2). It succeeded that insulating lead balls in low-melting metal were separated by electromagnetic force.

2009-10-15

60

Ramp rate testing of an HTS high gradient magnetic separation magnet  

Energy Technology Data Exchange (ETDEWEB)

The authors report on the ramp rate testing of a prototype high temperature superconducting (HTS) high gradient magnetic separation (HGMS) magnet. HGMS magnets are ramped from full field to zero field to clean the separation matrix. The time spent ramping the magnet is unavailable for processing and must therefore be kept to a minimum. Existing commercial low temperature superconducting HGMS magnets are immersed in a liquid helium bath and are designed to ramp from zero to full current in one minute. The HTS magnet in the system is conductively cooled and operates in a vacuum at a temperature of approximately 30 K. Heat generated during ramping is not as readily removed from the conductively cooled magnet as a bath cooled magnet. To verify that the conductive cooling can adequately remove heat generated during ramping they recorded magnet temperatures and voltages while ramping at rates of up to 4.8 A/second. The magnet can accommodate ramps from zero to 100 A (1.6 Tesla) in 21 seconds with no degradation in performance. The average magnet temperature rises a maximum of 1 K during ramping. Using temperatures recorded during ramps they have made rough estimates of the ac losses generated in the magnet.

Daugherty, M.A.; Roth, E.W.; Daney, D.E.; Hill, D.D.; Prenger, F.C.

1997-11-01

 
 
 
 
61

Dynamics of magnetic particles in cylindrical Halbach array: implications for magnetic cell separation and drug targeting.  

UK PubMed Central (United Kingdom)

Magnetic nanoparticles for therapy and diagnosis are at the leading edge of the rapidly developing field of bionanotechnology. In this study, we have theoretically studied motion of magnetic nano- as well as micro-particles in the field of cylindrical Halbach array of permanent magnets. Magnetic flux density was modeled as magnetostatic problem by finite element method and particle motion was described using system of ordinary differential equations--Newton law. Computations were done for nanoparticles Nanomag-D with radius 65 nm, which are often used in magnetic drug targeting, as well as microparticles DynaBeads-M280 with radius 1.4 microm, which can be used for magnetic separation. Analyzing snapshots of trajectories of hundred magnetite particles of each size in the water as well as in the air, we have found that optimally designed magnetic circuits of permanent magnets in quadrupolar Halbach array have substantially shorter capture time than simple blocks of permanent magnets commonly used in experiments, therefore, such a Halbach array may be useful as a potential source of magnetic field for magnetic separation and targeting of magnetic nanoparticles as well as microparticles for delivery of drugs, genes, and cells in various biomedical applications.

Babinec P; Krafcík A; Babincová M; Rosenecker J

2010-08-01

62

Dynamics of magnetic particles in cylindrical Halbach array: implications for magnetic cell separation and drug targeting.  

Science.gov (United States)

Magnetic nanoparticles for therapy and diagnosis are at the leading edge of the rapidly developing field of bionanotechnology. In this study, we have theoretically studied motion of magnetic nano- as well as micro-particles in the field of cylindrical Halbach array of permanent magnets. Magnetic flux density was modeled as magnetostatic problem by finite element method and particle motion was described using system of ordinary differential equations--Newton law. Computations were done for nanoparticles Nanomag-D with radius 65 nm, which are often used in magnetic drug targeting, as well as microparticles DynaBeads-M280 with radius 1.4 microm, which can be used for magnetic separation. Analyzing snapshots of trajectories of hundred magnetite particles of each size in the water as well as in the air, we have found that optimally designed magnetic circuits of permanent magnets in quadrupolar Halbach array have substantially shorter capture time than simple blocks of permanent magnets commonly used in experiments, therefore, such a Halbach array may be useful as a potential source of magnetic field for magnetic separation and targeting of magnetic nanoparticles as well as microparticles for delivery of drugs, genes, and cells in various biomedical applications. PMID:20517710

Babinec, Peter; Krafcík, Andrej; Babincová, Melánia; Rosenecker, Joseph

2010-06-02

63

Differential magnetic catch and release: experimental parameters for controlled separation of magnetic nanoparticles.  

Science.gov (United States)

Differential magnetic catch and release (DMCR) has been used as a method for the purification and separation of magnetic nanoparticles. DMCR separates nanoparticles in the mobile phase by magnetic trapping of magnetic nanoparticles against the wall of an open tubular capillary wrapped between two narrowly spaced electromagnetic poles. Using Au and CoFe(2)O(4) nanoparticles as model systems, the loading capacity of the 250 ?m diameter capillary is determined to be ?130 ?g, and is scalable to higher quantities with larger bore capillary. Peak resolution in DMCR is externally controlled by selection of the release time (R(t)) at which the magnetic flux density is removed, however, longer capture times are shown to reduce the capture yield. In addition, the magnetic nanoparticle capture yields are observed to depend on the nanoparticle diameter, mobile phase viscosity and velocity, and applied magnetic flux. Using these optimized parameters, three samples of CoFe(2)O(4) nanoparticles whose diameters are different by less than 10 nm are separated with excellent resolution and capture yield, demonstrating the capability of DMCR for separation and purification of magnetic nanoparticles. PMID:21562675

Beveridge, Jacob S; Stephens, Jason R; Williams, Mary Elizabeth

2011-05-12

64

Differential magnetic catch and release: experimental parameters for controlled separation of magnetic nanoparticles.  

UK PubMed Central (United Kingdom)

Differential magnetic catch and release (DMCR) has been used as a method for the purification and separation of magnetic nanoparticles. DMCR separates nanoparticles in the mobile phase by magnetic trapping of magnetic nanoparticles against the wall of an open tubular capillary wrapped between two narrowly spaced electromagnetic poles. Using Au and CoFe(2)O(4) nanoparticles as model systems, the loading capacity of the 250 ?m diameter capillary is determined to be ?130 ?g, and is scalable to higher quantities with larger bore capillary. Peak resolution in DMCR is externally controlled by selection of the release time (R(t)) at which the magnetic flux density is removed, however, longer capture times are shown to reduce the capture yield. In addition, the magnetic nanoparticle capture yields are observed to depend on the nanoparticle diameter, mobile phase viscosity and velocity, and applied magnetic flux. Using these optimized parameters, three samples of CoFe(2)O(4) nanoparticles whose diameters are different by less than 10 nm are separated with excellent resolution and capture yield, demonstrating the capability of DMCR for separation and purification of magnetic nanoparticles.

Beveridge JS; Stephens JR; Williams ME

2011-06-01

65

Feasibility study of iron mineral separation from red mud by high gradient superconducting magnetic separation  

Science.gov (United States)

The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (<100 ?m) into high iron content part and low iron content part. Two sorts of RM were fed in the HGSMS. The iron oxide contents in concentrates were about 65% and 45% when RM 1# and RM 2# were fed respectively. Meanwhile, the residues contained 52.0% or 14.1% iron oxide in residues after eight separation stages when RM 1# and RM 2# were fed respectively. The mass recovery of iron concentrates was about 10% after once separation process regardless of RM 1# or RM 2# was fed. Extreme fine particles (<10 ?m) could be captured in the HGSMS. Intergrowth of Fe and other elements is disadvantages for iron mineral separation from RM by HGSMS. Some improvement should be studied to enhance the efficiency of iron separation. It is possible for HGSMS to separate RM into high iron content part and low iron content part, the former part could be used in iron-making furnace and the later part could be recycling to sintering process for alumina production or used as construction material.

Li, Yiran; Wang, Jun; Wang, Xiaojun; Wang, Baoqiang; Luan, Zhaokun

2011-02-01

66

Capture of metallic copper by high gradient magnetic separation system.  

UK PubMed Central (United Kingdom)

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 with a permalloy matrix net under a high gradient magnetic field. The captured solids were predominantly 6-20 microm in diameter, with Cu2O and CuO present among the solids. Four treatment configurations with and without the use of magnetic field and metal alloy as the matrix net were tested and their effects evaluated: (1) no magnetic field or matrix, (2) no magnetic field but with matrix, (3) with magnetic field but no matrix, (4) with both magnetic field and matrix. At flow rates of 40, 60, 80 and 100 cm3/min, capture efficiencies for metallic copper in the absence of magnetic field were 87%, 86%, 63%, and 39%, respectively, and in the presence of magnetic field were 99%, 98%, 95%, and 93%, respectively. The HGMS was critical for a high capture efficiency, whereas a matrix net only marginally enhanced it. Additional tests with a larger reactor confirmed similarly high efficiencies of > 85%. The use of an alloy matrix appeared to be important when high flow rates are most likely to be employed in practical applications.

Wu WI; Wu CH; Hong PK; Lin CF

2011-10-01

67

Beneficiation of Turkish lignites by thermal treatment and magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

In this paper, the improvement of Turkish lignites by semi-coking and REMS magnetic separation, in two stages, is discussed. The oxidation and decomposition of pyrite through the thermal treatment result in the formation of iron oxide and pyrrhotite on the surface. In addition to pyrite, part of the organic sulfur is also removed. After thermal treatment of lignites at temperatures ranging from 370 to 650 C, the application of REMS magnetic separator produces a product higher in calorific value and lower in sulfur content. The product can be utilized after briquetting. The volatile gases can also be used after sulfur removal. This process appears to be feasible as a clean coal manufacture from the point of energy efficiency. A short economic analysis is also presented.

Onal, G.; Renda, D.; Mustafaev, I.; Dogan, Z.

1999-07-01

68

Magnetic Separation for Nuclear Material Detection and Surveillance  

International Nuclear Information System (INIS)

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 0.8microm PuO2 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.

1998-01-01

69

Application of blind source separation to nuclear magnetic resonance  

International Nuclear Information System (INIS)

Blind source separation is intended to decompose signal mixtures into statistically independent components. Application of this technique to the analysis of organic molecules by nuclear magnetic resonance (NMR) are presented. The goal of this study is to demonstrate the simplification of spectral analysis in three cases: the analysis of mixtures of compounds, the analysis of a single mixture and the splitting of the spectrum of a pure compound into simpler sub-spectra. (authors)

1999-01-01

70

Heavy ion separation with a gas-filled magnetic spectrograph  

International Nuclear Information System (INIS)

[en] Heavy ions passing through a magnetic field region filled with gas experience atomic charge-changing collisions and follow trajectories approximately determined by the mean charge state in the gas. The properties of a gas-filled Enge magnetic spectrograph are studied in detail by measuring focal-plane position spectra of fast heavy ions and their evolution as a function of gas pressure. The method allows physical separation of pairs of isobaric ions in the focal plane. Applications in accelerator mass spectrometry experiments are described. At intermediate low pressures, single atomic charge-changing processes can be identified. A Monte Carlo simulation program of the ion transport through the gas-filled magnet is developed and reproduced closely the experimental behavior. (orig.)

1989-05-01

71

New Applications of Magnetic Separation Using Superconducting Magnets and Colloid Chemical Processes  

Science.gov (United States)

High gradient magnetic separation (HGMS) can be a promising new environmental purification technique as it produces no contaminants, such as flocculants, and could possibly treat large amounts of waste water within a short time frame. A colloid chemical process for magnetic seeding can allow us to rapidly recover a large quantity of adsorbate and to strongly magnetize individual particles in order to improve the recovery efficiency of magnetic separation. In this paper, we will report on the fundamental study of the magnetic seeding process and purification processes using HGMS, and also on studies of applications of the water treatment system for actual factories. Emphasized is a report on a system constructed for water treatment from a paper-manufacturing factory.

Takeda, S.; Yu, S.-J.; Nakahira, A.; Izumi, Y.; Nishijima, S.; Watanabe, T.

2005-07-01

72

Magnetically separable titania-coated nickel ferrite photocatalyst  

International Nuclear Information System (INIS)

A magnetically separable photocatalyst was prepared by a continuous multi-step spray pyrolysis process. In the first step, nickel ferrite core particles were prepared by an ultrasonic spray pyrolysis. In the second step, tetraethyl orthosilicate (TEOS) and titanium isopropoxide (TTIP) were sequentially injected and coated on the surface of the core particles. The sequentially coated layers were decomposed to form silica and titania layers in a final furnace reactor. The titania-silica layered particles displayed higher photoactivity than particles coated only with titania and titania-silica mixture-coated particles. The photoactivity of the titania-silica layered particles remained unchanged after magnetic separation and washing. This confirms that the adhesion between the core particles and the coated layer is strong enough to withstand vigorous mixing. It also implies that the formation of free particles of silica or titania is negligible in the second reactor. The strong adhesion between the coated layer and the nickel ferrite core is attributed to the features of the multi-step process, wherein the core particles are exposed to high temperate in the second reactor for only a few seconds and transformation of the core particles into non-magnetic particles is prohibited.

2004-01-01

73

Development of a highly magnetic iron sulphide for metal uptake and magnetic separation  

International Nuclear Information System (INIS)

Microbial iron sulphide (FeS) is a well-known absorbent for heavy metals which has the potential to be used in biomagnetic separation. This paper illustrates that highly magnetic FeS can be produced from bioreactors which are continually switched between batch and continuous culture modes. Cadmium metal uptake studies highlight the sulphide absorbent properties of the FeS produced.

2005-01-01

74

Application of high gradient magnetic separation principles to magnetic drug targeting  

International Nuclear Information System (INIS)

[en] A hypothetical magnetic drug targeting system, utilizing high gradient magnetic separation (HGMS) principles, was studied theoretically using FEMLAB simulations. This new approach uses a ferromagnetic wire placed at a bifurcation point inside a blood vessel and an externally applied magnetic field, to magnetically guide magnetic drug carrier particles (MDCP) through the circulatory system and then to magnetically retain them at a target site. Wire collection (CE) and diversion (DE) efficiencies were defined and used to evaluate the system performance. CE and DE both increase as the strength of the applied magnetic field (0.3-2.0 T), the amount of ferromagnetic material (iron) in the MDCP (20-100%) and the size of the MDCP (1-10 ?m radius) increase, and as the average inlet velocity (0.1-0.8 m s-1), the size of the wire (50-250 ?m radius) and the ratio (4-10) of the parent vessel radius (0.25-1.25 mm radius) to wire radius decrease. The effect of the applied magnetic field direction (0 deg. and 90 deg. ) on CE and DE was minimal. Under these plausible conditions, CEs as high as 70% were obtained, with DEs reaching only 30%; however, when the MDCPs were allowed to agglomerate (4-10 ?m radius), CEs and DEs of 100% were indeed achieved. These results reveal that this new magnetic drug targeting approach for magnetically collecting MDCPs at a target site, even in arteries with very high velocities, is feasible and very promising; this new approach for magnetically guiding MDCPs through the circulatory system is also feasible but more limited. Overall, this study shows that magnetic drug targeting, based on HGMS principles, has considerable promise as an effective drug targeting tool with many potential applications

2004-01-01

75

Application of high gradient magnetic separation principles to magnetic drug targeting  

Energy Technology Data Exchange (ETDEWEB)

A hypothetical magnetic drug targeting system, utilizing high gradient magnetic separation (HGMS) principles, was studied theoretically using FEMLAB simulations. This new approach uses a ferromagnetic wire placed at a bifurcation point inside a blood vessel and an externally applied magnetic field, to magnetically guide magnetic drug carrier particles (MDCP) through the circulatory system and then to magnetically retain them at a target site. Wire collection (CE) and diversion (DE) efficiencies were defined and used to evaluate the system performance. CE and DE both increase as the strength of the applied magnetic field (0.3-2.0 T), the amount of ferromagnetic material (iron) in the MDCP (20-100%) and the size of the MDCP (1-10 {mu}m radius) increase, and as the average inlet velocity (0.1-0.8 m s{sup -1}), the size of the wire (50-250 {mu}m radius) and the ratio (4-10) of the parent vessel radius (0.25-1.25 mm radius) to wire radius decrease. The effect of the applied magnetic field direction (0 deg. and 90 deg. ) on CE and DE was minimal. Under these plausible conditions, CEs as high as 70% were obtained, with DEs reaching only 30%; however, when the MDCPs were allowed to agglomerate (4-10 {mu}m radius), CEs and DEs of 100% were indeed achieved. These results reveal that this new magnetic drug targeting approach for magnetically collecting MDCPs at a target site, even in arteries with very high velocities, is feasible and very promising; this new approach for magnetically guiding MDCPs through the circulatory system is also feasible but more limited. Overall, this study shows that magnetic drug targeting, based on HGMS principles, has considerable promise as an effective drug targeting tool with many potential applications.

Ritter, J.A. E-mail: ritter@engr.sc.edu; Ebner, A.D.; Daniel, K.D.; Stewart, K.L

2004-09-01

76

Mercury removal from solution by superconducting magnetic separation with nanostructured magnetic adsorbents  

International Nuclear Information System (INIS)

Recently, mercury Hg concentration in human blood increases due to expanding the global mercury contamination. Excess mercury bioaccumulation poses a significant health risk. In order to decrease mercury concentration in the environment and human blood, we have developed two different kinds of nanostructured magnetic adsorbents for mercury to apply them to superconducting magnetic separation instead of conventional filtration. One is magnetic beads (MBs) which have nanosize magnetite particles in the core and a lot of SH radicals on the surface to adsorb Hg ions effectively. MBs were developed mainly to remove mercury from human blood. The maximum amount of the adsorption for MBs is 6.3 mg/g in the solution in less than a minute. Dithiothreitol can easily remove mercury adsorbed to MBs, hence MBs can be reusable. The other is nanostructured magnetic activated carbon (MAC) which is activated carbon with mesopores and nanosize magnetite. The maximum amount of the adsorption for MAC is 38.3 mg/g in the solution. By heat-treatment mercury can be easily removed from MAC. We have studied superconducting magnetic separation using each adsorbent for mercury removal from solution.

2011-01-01

77

Large Scale Magnetic Separation of Solanum tuberosum Tuber Lectin from Potato Starch Waste Water  

Science.gov (United States)

A simple procedure for large scale isolation of Solanum tuberosum tuber lectin from potato starch industry waste water has been developed. The procedure employed magnetic chitosan microparticles as an affinity adsorbent. Magnetic separation was performed in a flow-through magnetic separation system. The adsorbed lectin was eluted with glycine/HCl buffer, pH 2.2. The specific activity of separated lectin increased approximately 27 times during the isolation process.

Safarik, Ivo; Horska, Katerina; Martinez, Lluis M.; Safarikova, Mirka

2010-12-01

78

Application of high temperature superconductors to high-gradient magnetic separation  

International Nuclear Information System (INIS)

[en] 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 the authors 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

1994-01-01

79

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

DEFF Research Database (Denmark)

We present a theoretical analysis of a new design for microfluidic magnetic bead separation. It combines an external array of mm-sized permanent magnets with magnetization directions alternating between up and down with mu m-sized soft magnetic structures integrated in the bottom of the separation channel. The concept is studied analytically for simple representative geometries and by numerical simulation of an experimentally realistic system geometry. The array of permanent magnets provides long-range magnetic forces that attract the beads to the channel bottom, while the soft magnetic elements provide strong local retaining forces that prevent captured beads from being torn loose by the fluid drag. The addition of the soft magnetic elements increases the maximum retaining force by two orders of magnitude. The design is scalable and provides an efficient and simple solution to the capture of large amounts of magnetic beads on a microsystem platform.

Smistrup, Kristian; Bu, Minqiang

2008-01-01

80

Magnetic separation in microfluidic systems using microfabricated electromagnets-experiments and simulations  

Energy Technology Data Exchange (ETDEWEB)

We present experiments and simulations of magnetic separation of magnetic beads in a microfluidic channel. The separation is obtained by microfabricated electromagnets. The results of our simulations using FEMLAB and Mathematica are compared with experimental results obtained using our own microfabricated systems.

Smistrup, Kristian [MIC-Department of Micro and Nanotechnology, Technical University of Denmark, DTU - Building 345 East, DK-2800 Kongens Lyngby (Denmark)]. E-mail: krs@mic.dtu.dk; Hansen, Ole [MIC-Department of Micro and Nanotechnology, Technical University of Denmark, DTU - Building 345 East, DK-2800 Kongens Lyngby (Denmark); Bruus, Henrik [MIC-Department of Micro and Nanotechnology, Technical University of Denmark, DTU - Building 345 East, DK-2800 Kongens Lyngby (Denmark); Hansen, Mikkel F. [MIC-Department of Micro and Nanotechnology, Technical University of Denmark, DTU - Building 345 East, DK-2800 Kongens Lyngby (Denmark)

2005-05-15

 
 
 
 
81

Purification of condenser water in thermal power station by superconducting magnetic separation  

International Nuclear Information System (INIS)

Magnetic separation using cryo-cooled Nb-Ti superconducting magnet was applied for the purification of condenser water. Iron oxides in condenser water were effectively removed by superconducting magnetic separation. The effect of magnetic field strength and filter size was determined. Thermal power station is made up of a steam turbine and a steam condenser which need a lot of water. The water of steam condenser should be replaced, since scales consisting of iron oxide mainly are accumulated on the surface of condenser pipes as it goes. Superconducting high gradient magnetic separation (HGMS) system has merits to remove paramagnetic substance like iron oxides because it can generate higher magnetic field strength than electromagnet or permanent magnet. In this paper, cryo-cooled Nb-Ti superconducting magnet that can generate up to 6 T was used for HGMS systems. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The result of X-ray analysis showed contaminants were mostly ?-Fe2O3 (hematite) and ?-Fe2O3 (maghemite). The higher magnetic field was applied up to 6 T, the more iron oxides were removed. As the wire diameter of magnetic filter decreased, the turbidity removal of the sample was enhanced.

2011-01-01

82

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

UK PubMed Central (United Kingdom)

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.

Tian A; Qi J; Liu Y; Wang F; Ito Y; Wei Y

2013-08-01

83

Theoretical analysis of a simple yet efficient portable magnetic separator design for separation of magnetic nano/micro-carriers from human blood flow  

International Nuclear Information System (INIS)

A technology that could physically remove substances from the blood such as biological, chemical, or radiological toxins could dramatically improve treatment of disease. One method in development proposes to use magnetic-polymer spheres to selectively bind toxins and remove them by magnetic filtration. Although magnetic filtration is a developed technology, the clinical boundary conditions described here require a new filter design. We investigated the removal of toxin-bound magnetic carriers from the blood stream using 2-D FEMLAB simulations. The magnetic separator consisted of a permanent magnet with parallel ferromagnetic prisms on the faces and in contact with a straight tube carrying the magnetic-polymer spheres in suspension. We varied the following parameters: blood flow velocity, the size, and number of ferromagnetic prisms, and the ferromagnetic material in both prisms and magnets. The capture efficiency reached maximum values when the depth of the prisms equaled the diameter of the tubing and the saturation magnetization of the prism material equaled twice that of the magnet. With this design a piece of 2 mm (diameter) tube carrying the fluid resulted in 95% capture of 2.0 ?m magnetic-polymer spheres at 10 cm/s flow velocity.

2007-01-01

84

Phase separation in La-Ca manganites: Magnetic field effects  

International Nuclear Information System (INIS)

The coexistence of magnetic phases seems to be a characteristic of the La-Ca family of in colossal magnetoresistant manganites. We have analyzed this phenomenon in terms of a free energy, F, where magnetic and electronic contributions of two coexistent phases are included. Three order parameters describe the behavior of the mixed material: the magnetization of each phase and the metallic fraction. Due to the coupling between order parameters there is a range: T**?T?T* where coexistence is possible. Values for the phenomenological parameters are obtained from the experiment. In this paper we analyze the effects of an applied magnetic field on the range of T where the phase coexistence takes place, based on results obtained from dc-magnetization and ESR measurements.

2008-01-01

85

Functionalization of magnetic gold/iron-oxide composite nanoparticles with oligonucleotides and magnetic separation of specific target  

Energy Technology Data Exchange (ETDEWEB)

Magnetic composite nanoparticles of gold and iron-oxide synthesized with gamma-rays or ultrasonics were functionalized with thiol-modified oligonucleotides. The amount of oligonucleotides bound to the functionalized nanoparticle probes via hybridization was quantified with fluorescently-labeled target oligonucleotides. Our composite nanoparticles magnetically separated the specific target oligonucleotides without the non-specific adsorption.

Kinoshita, Takuya [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)]. E-mail: t-kinoshita@mit.eng.osaka-u.ac.jp; Seino, Satoshi [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mizukoshi, Yoshiteru [Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan); Nakagawa, Takashi [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Yamamoto, Takao A. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2007-04-15

86

Functionalization of magnetic gold/iron-oxide composite nanoparticles with oligonucleotides and magnetic separation of specific target  

International Nuclear Information System (INIS)

[en] Magnetic composite nanoparticles of gold and iron-oxide synthesized with gamma-rays or ultrasonics were functionalized with thiol-modified oligonucleotides. The amount of oligonucleotides bound to the functionalized nanoparticle probes via hybridization was quantified with fluorescently-labeled target oligonucleotides. Our composite nanoparticles magnetically separated the specific target oligonucleotides without the non-specific adsorption

2007-01-01

87

Separation of spin and orbital magnetizations in a samarium film  

International Nuclear Information System (INIS)

The L/S ratio of samarium has been determined by X-ray magnetic scattering from a thick epitaxial film, via the azimuthal dependence of the scattered intensity. This new method allows a direct determination of L/S in antiferromagnetic systems where charge scattering is not negligible at the position of the magnetic signal. The Russell-Saunders predictions fall within the accuracy of our results

2003-08-01

88

Colossal magnetoresistance and phase separation in magnetic semiconductors  

CERN Document Server

Colossal magnetoresistance materials, to which manganites and conventional ferromagnetic semiconductors belong, draw great attention because of their intriguing physical properties and the excellent prospects for their practical applications in electronic devices. In addition, magnetic semiconductors are basic materials for high-temperature conductors, and it is impossible to construct a theory of the latter without elucidating properties of the former.This book presents theoretical and experimental results on manganites and conventional magnetic semiconductors, with emphasis on the former. It

Nagaev, Eduard L

2002-01-01

89

Removal of algal blooms from freshwater by the coagulation-magnetic separation method.  

UK PubMed Central (United Kingdom)

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.

Liu D; Wang P; Wei G; Dong W; Hui F

2013-01-01

90

Magnetic particle separation in viscous flows by BEM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A boundary element method based solver for particle motion simulation in dilute suspensions under the influence of hydrodynamic and magnetic forces was applied. The Euler-Lagrangian formulation for simulation of dilute two-phase flow was applied. The algorithm solves the incompressible Navier-Stokes...

Hriberšek, Matjaž; Ravnik, Jure; Kocutar, Primož

91

Separability of center of mass and relative motion of hydrogen in very strong magnetic fields  

Energy Technology Data Exchange (ETDEWEB)

While hydrogen does not strictly separate into center of mass (CMS) and relative motion in a magnetic field, a judicious gauge choice does lead to a simple Hamiltonian whose form in a state of zero translational motion of the center of mass is that of a charged particle in a magnetic field plus a coulomb potential.

Palmer, W.F.; Taylor, R.J.

1980-01-01

92

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

UK PubMed Central (United Kingdom)

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.

Giakisikli G; Anthemidis AN

2013-07-01

93

High gradient magnetic separation (HGMS) of erythrocytes infected with plasmodium falciparum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis was undertaken to explore possible applications of high gradient magnetic separation (HGMS) for the separation of RBCs infected with Plasmodium falciparum, with the dual aim of establishing a novel and superior method for isolating late-stage infected cells, and of obtaining synchronized...

Ottinger, Annette

94

Magnetic supramolecular grid structures: Intramolecular coupling of four separate spins  

Energy Technology Data Exchange (ETDEWEB)

The magnetization of novel tetranuclear supramolecular grid structures and their mononuclear analogues were measured. In the tetranuclear complexes with Co{sup 2+} or Ni{sup 2+} ions an intramolecular antiferromagnetic coupling of the four metal centers is observed. The isotropic coupling strength was determined to be J = {minus}8 K for the Ni{sup 2+} grids, and J = {minus}2 K for the Co{sup 2+} grids.

Waldmann, O.; Hassmann, J.; Koch, R.; Mueller, P.; Hanan, G.S.; Volkmer, D.; Schubert, U.S.; Lehn, J.M.

1998-07-01

95

Separation of Uranium by an Extractant Encapsulated Magnetic Alginate Gels  

Science.gov (United States)

The aim of this work is to prepare environmentally friendly and practically applicable alginate magnetic biopolymers encapsulated tri-n-butyl phosphate (TBP) for the removal uranium ions. Some important process parameters such as initial pH, initial U(VI) concentration, adsorbent dosage, time, temperature and sorption isotherms for uranium uptake were studied and the thermodynamic parameters for U(VI) were determined.

Portakal, Z.; Gok, C.; Aytas, S.

96

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

UK PubMed Central (United Kingdom)

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 mum 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 mum 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 ngml 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.

Florescu O; Wang K; Au P; Tang J; Harris E; Beatty PR; Boser BE

2010-03-01

97

Use of high-gradient magnetic fields for the separation of macromolecules  

Energy Technology Data Exchange (ETDEWEB)

High gradient magnetic field separation (HGMS) has been used to separate several types of > 1 ..mu..m sized ferro- or paramagnetic particles from bulk streams. The majority of the studies have been carried out using a single ferromagnetic wire or wire mesh to produce the field gradients necessary for particle capture. The purpose of this paper is to examine the possibility of using HGMS on < 1 ..mu..m entities for the purpose of macromolecular separations. Preliminary experimental results demonstrate that HGMS techniques can be used to capture 0.1 ..mu..M diam latex beads from a paramagnetic salt solution passing through a columnar bed of ferro-magnetic spheres.

Scott, T.C.; Brumfield, T.L.

1988-10-01

98

Non-locality of energy separating transformations for Dirac electrons in a magnetic field  

CERN Document Server

We investigate a non-locality of Moss-Okninski transformation (MOT), used to separate positive and negative energy states in the Dirac equation for relativistic electrons in the presence of a magnetic field. Properties of functional kernels generated by the MOT are analyzed and kernel non-localities are characterized by calculating their second moments parallel and perpendicular to the magnetic field. Transformed functions are described and investigated by computing their variances. It is shown that the non-locality of the energy-separating transformation in the direction parallel to the magnetic field is characterized by the Compton wavelength $\\lambda_c=\\hbar/mc$. In the plane transverse to magnetic field the non-locality depends both on magnetic radius $L=(\\hbar/eB)^{1/2}$ and $\\lambda_c$.

Rusin, Tomasz M

2011-01-01

99

Magnetic phase separation in EuB6 detected by muon spin rotation  

CERN Document Server

We report results of the first muon-spin rotation measurements performed on the low carrier density ferromagnet EuB$_6$. The ferromagnetic state is reached via two magnetic transitions at $T_{\\rm m}=16.5$ K and $T_{\\rm c}=12.6$ K. Two distinct components are resolved in the muon data, one oscillatory and one non-oscillatory, which arise from different types of magnetic environment, and we have followed the temperature dependence of these components in detail. These results provide evidence for magnetic phase separation and can be interpreted in terms of the gradual coalescing of magnetic polarons.

Brooks, M L; Blundell, S J; Hayes, W; Pratt, F L; Fisk, Z

2004-01-01

100

Magnetically induced pattern formation in phase separating polymer-solvent-nanoparticle mixtures.  

UK PubMed Central (United Kingdom)

Permanent magnetic structures with controlled dimension and architecture (labyrinthine, hexagonal, or dispersed columnar) are formed in a partially miscible ferrofluid-nonferrofluid mixture under the influence of a perpendicular magnetic field. The origin of the permanent structures, which have characteristic lateral dimensions ranging from 1 to 10???m, is the repartitioning of the ferrofluid carrier solvent into the nonferrofluid polymeric phase. This polymer-solvent phase separation under a magnetic field leads to departures from the expected final dimension of the magnetically stabilized ferrofluid droplet sizes.

Rungsawang R; da Silva J; Wu CP; Sivaniah E; Ionescu A; Barnes CH; Darton NJ

2010-06-01

 
 
 
 
101

Field emission resonances on the quasi one-dimensional Si(111)5 x 2-Au reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Scanning tunnelling spectroscopy measurements of field emission resonances (FER) have shown to be a suitable tool to investigate local work function variations particularly on metal surfaces. About FER on semiconductors or nanostructured surfaces less literature can be found. In this contribution we compare FER on different regions of a Si(111)7 x 7 substrate which is partially covered by the quasi one-dimensional Si(111)5 x 2-Au structure. Across a transition between Si(111)7 x 7 and Si(111)5 x 2-Au a shift of the FER peak positions is found which can be attributed to changes of the local work function. At increased spatial resolution dI/dV maps reveal a periodic shift of the higher order FER in the direction perpendicular to the chains of Si(111)5 x 2-Au. This effect appears on a length scale of less than one nanometer and is caused by surface-potential variations. Model calculations are shown to quantify their amplitude.

Polei, Stefan; Barke, Ingo; Sell, Kristian; Oeynhausen, Viola von; Meiwes-Broer, Karl-Heinz [Institut fuer Physik, Universitaet Rostock, D-18051, Rostock (Germany)

2011-07-01

102

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

Energy Technology Data Exchange (ETDEWEB)

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

Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Landsberger, S. [Univ. of Illinois, Urbana, IL (United States)

1995-05-01

103

Setting up High Gradient Magnetic Separation for combating eutrophication of inland waters.  

UK PubMed Central (United Kingdom)

To find new approaches to devise technologies for handling with eutrophication of inland waters is a global challenge. Separation of the P from water under conditions of continuous flow is proposed as an alternative and effective method. This work is based on using highly magnetic particles as the seeding adsorbent material and their later removal from solution by High Gradient Magnetic Separation (HGMS). Contrast to other methods based on batch conditions, large volumes of water can be easily handled by HGMS because of decreasing retention times. This study identifies the best working conditions for removing P from solution by investigating the effects of a set of four different experimental variables: sonication time, flow rate (as it determines the retention time of particles in the magnetic field), magnetic field strength and the iron (Fe) particles/P concentration ratio. Additionally, the change of P removal efficiency with time (build up effect) and the possibility of reusing magnetic particles were also studied. Our results evidenced that while flow rate does not significantly affect P removal efficiency in the range 0.08-0.36 mL s(-1), sonication time, magnetic field strength and the Fe particles/P concentration ratio are the main factors controlling magnetic separation process.

Merino-Martos A; de Vicente J; Cruz-Pizarro L; de Vicente I

2011-02-01

104

SEPARATOR  

UK PubMed Central (United Kingdom)

A separator for a suction air-solid-liquid mixture in a dental suction apparatus has an intermediate container (32) situated beneath an air separation chamber (5), which has an outlet (8) for the separated mixture. Associated with and situated along side the mixture outlet (8), a separation device (10) for the solids has a removable sedimentation basin (21) and a clean liquid outlet (13) through which the clean liquid is conveyed into the intermediate container (32). A tube (6) connecting with the second segment (2) of the suction line passes through the intermediate container (32) from the air separation chamber (5) and has a clean liquid admission port (33) so that the solids-free liquid is fed back into the suction air.

TRAWÖGER Werner; PREGENZER Bruno

105

Spin Waves, Phase Separation, and Interphase Boundaries in Double Exchange Magnets  

CERN Multimedia

We study a classical double exchange magnet with direct antiferromagnetic superexchange coupling, J, between the localized spins. It is shown that the de-stabilization of the ferromagnetic ground state with increasing J leads to phase separation; the latter always circumvents the spin-wave instability (softening of the magnon spectrum). It is also found that the boundaries separating the ferromagnetic and antiferromagnetic areas of the sample tend to be abrupt.

Golosov, D I

2001-01-01

106

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

Science.gov (United States)

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, S; Kraf?ík, A; Babincová, M; Babinec, P

2012-12-21

107

Ferromagnetic Ni decorated ordered mesoporous carbons as magnetically separable adsorbents for methyl orange  

International Nuclear Information System (INIS)

Highlights: ? Magnetically separable Ni-decorated ordered mesoporous carbon (OMC) was successfully synthesized. ? The adsorption capacities for MO dyes on ordered mesoporous carbons, Ni-OMC and activated carbon powder were comparatively investigated. ? The effects of surface area, pore structure, and Ni deposition on the absorption capacities for MO were investigated. ? The ferromagnetic Ni decorated OMC can be easily dispersed in aqueous solution and removed by an external magnetic field. - Abstract: Magnetic ordered mesoporous carbons (OMCs) with Ni nanoparticle (average size: 10 nm) homogeneously modified on surfaces of OMCs were successfully fabricated via a facile casting route. The microstructure, pore size distribution, pore structure, and surface area of the synthesized OMCs and Ni decorated OMCs (Ni-OMCs) were characterized by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy and N2 sorption. The characterization by magnetic hysteresis loops suggests a ferromagnetic behavior for the Ni-OMCs samples with a magnetization saturation of 2.34 emu g?1 at 300 K, high enough for magnetic separation. The ferromagnetic Ni-OMCs were used as magnetically separable high-performance adsorbents for methyl orange (MO). The adsorption capacities for MO on the Ni-OMCs as magnetically separable adsorbents were investigated comparatively with pristine OMCs and activated carbon powder (ACP). The results show that the adsorption capacities for MO on the OMCs and Ni-OMCs adsorbents could be well described according to Langmuir isotherm with MO molecule preferentially adsorbed in the structured mesopores, suggesting the adsorption type of monolayer coverage of MO dye onto the mesoporous samples. The effects of surface area, pore structure, and the Ni deposition on the adsorption capacities for MO were systematically investigated. The effects of several important parameters such as contact time, temperature, adsorbent dosage and adsorbate concentration on the adsorption capabilities were studied in detail. The ferromagnetic Ni decorated OMCs as adsorbents for MO, were easily dispersed, separated and removed in an external applied magnet field, and can be more convenient for large scale applications than filtration or centrifugation separation route.

2011-12-15

108

Recovery of iron from cyanide tailings with reduction roasting-water leaching followed by magnetic separation.  

UK PubMed Central (United Kingdom)

Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting-water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism.

Zhang Y; Li H; Yu X

2012-04-01

109

Purification of condenser water in thermal power station by superconducting magnetic separation  

Science.gov (United States)

Thermal power station is made up of a steam turbine and a steam condenser which need a lot of water. The water of steam condenser should be replaced, since scales consisting of iron oxide mainly are accumulated on the surface of condenser pipes as it goes. Superconducting high gradient magnetic separation (HGMS) system has merits to remove paramagnetic substance like iron oxides because it can generate higher magnetic field strength than electromagnet or permanent magnet. In this paper, cryo-cooled Nb-Ti superconducting magnet that can generate up to 6 T was used for HGMS systems. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The result of X-ray analysis showed contaminants were mostly ?-Fe2O3 (hematite) and ?-Fe2O3 (maghemite). The higher magnetic field was applied up to 6 T, the more iron oxides were removed. As the wire diameter of magnetic filter decreased, the turbidity removal of the sample was enhanced.

Ha, D. W.; Kwon, J. M.; Baik, S. K.; Lee, Y. J.; Han, K. S.; Ko, R. K.; Sohn, M. H.; Seong, K. C.

2011-11-01

110

High intensity magnetic separation for the clean-up of a site polluted by lead metallurgy.  

UK PubMed Central (United Kingdom)

The industrial history in the district of Linares (Spain) has had a severe impact on soil quality. Here we examined soil contaminated by lead and other heavy metals in "La Cruz" site, a brownfield affected by metallurgical residues. Initially, the presence of contaminants mainly associated with the presence of lead slag fragments mixed with the soil was evaluated. The subsequent analysis showed a quasi-uniform distribution of the pollution irrespective of the grain-size fractions. This study was accompanied by a characterization of the lead slag behavior under the presence of a magnetic field. Two main magnetic components were detected: first a ferromagnetic and/or ferrimagnetic contribution, second a paramagnetic and/or antiferromagnetic one. It was also established that the slag was composed mainly of lead spherules and iron oxides embedded in a silicate matrix. Under these conditions, the capacity of magnetic separation to remove pollutants was examined. Therefore, two high intensity magnetic separators (dry and wet devices, respectively) were used. Dry separation proved to be successful at decontaminating soil in the first stages of a soil washing plant. In contrast, wet separation was found effective as a post-process for the finer fractions.

Sierra C; Martínez J; Menéndez-Aguado JM; Afif E; Gallego JR

2013-03-01

111

Magnetically Separable Base Catalysts: Heterogeneous Catalysis vs. Quasi-Homogeneous Catalysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The synthesis of magnetically separable quasi-homogeneous base catalyst and heterogeneous base catalyst is described. The quasi-homogeneous catalyst is achieved by supporting silane monomers functionalized with different amine groups directly on the surface of magnetite nanoparticles. The heterogene...

Raed Abu-Reziq; Howard Alper

112

Calibration of analyzing magnet for beam energy measurement using the recoil mass separator HIRA  

Energy Technology Data Exchange (ETDEWEB)

Beam energy measurements have been carried out using the energy achromatic recoil mass separator HIRA at NSC. The energy was obtained from a measurement of the time-of-flight through HIRA which offers a flight distance of about 8.8 m. The method is quite useful for the calibration of the analyzer magnet over the entire operating range. (orig.).

Madhavan, N. [Nuclear Sci. Centre, New Delhi (India); Das, J.J. [Nuclear Sci. Centre, New Delhi (India); Sugathan, P. [Nuclear Sci. Centre, New Delhi (India); Kataria, D.O. [Nuclear Sci. Centre, New Delhi (India); Avasthi, D.K. [Nuclear Sci. Centre, New Delhi (India); Mandal, A. [Nuclear Sci. Centre, New Delhi (India); Sinha, A.K. [Nuclear Sci. Centre, New Delhi (India)

1996-02-21

113

Blind Source Separation of Hemodynamics from Magnetic Resonance Perfusion Brain Images Using Independent Factor Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Perfusion magnetic resonance brain imaging induces temporal signal changes on brain tissues, manifesting distinct blood-supply patterns for the profound analysis of cerebral hemodynamics. We employed independent factor analysis to blindly separate such dynamic images into different maps, that is, ar...

Chou, Yen-Chun; Lu, Chia-Feng; Guo, Wan-Yuo; Wu, Yu-Te

114

High efficiency protein separation with organosilane assembled silica coated magnetic nanoparticles  

Science.gov (United States)

This work describes the development of high efficiency protein separation with functionalized organosilanes on the surface of silica coated magnetic nanoparticles. The magnetic nanoparticles were synthesized with average particle size of 9 nm and silica coated magnetic nanoparticles were obtained by controlling the coating thicknesses on magnetic nanoparticles. The silica coating thickness could be uniformly sized with a diameter of 10 40 nm by a sol gel approach. The surface modification was performed with four kinds of functionalized organosilanes such as carboxyl, aldehyde, amine, and thiol groups. The protein separation work with organosilane assembled silica coated magnetic nanoparticles was achieved for model proteins such as bovine serum albumin (BSA) and lysozyme (LSZ) at different pH conditions. Among the various functionalities, the thiol group showed good separation efficiency due to the change of electrostatic interactions and protein conformational structure. The adsorption efficiency of BSA and LSZ was up to 74% and 90% corresponding pH 4.65 and pH 11.

Chang, Jeong Ho; Kang, Ki Ho; Choi, Jinsub; Jeong, Young Keun

2008-10-01

115

Use of high-gradient magnetic fields for the separation of macromolecules  

Energy Technology Data Exchange (ETDEWEB)

High gradient magnetic field separation (HGMS) has been used to separate several types of > 1 ..mu..m sized ferro- or paramagnetic particles from bulk streams. The majority of the studies have been carried out using a single ferromagnetic wire or wire mesh to produce the field gradients necessary for particle capture. The purpose of this paper is to examine the possibility of using HGMS on < 1 ..mu..m entities for the purpose of macromolecular separations. Preliminary experimental results demonstrate that HGMS techniques can be used to capture 0.1 ..mu..m diam latex beads from a paramagnetic salt solution passing through a columnar bed of ferro- magnetic spheres. 10 refs., 3 figs.

Scott, T.C.; Brumfield, T.L.

1987-01-01

116

On-chip free-flow magnetophoresis: Separation and detection of mixtures of magnetic particles in continuous flow  

International Nuclear Information System (INIS)

The complete separation of mixtures of magnetic particles was achieved by on-chip free-flow magnetophoresis. In continuous flow, magnetic particles were deflected from the direction of laminar flow by a perpendicular magnetic field depending on their magnetic susceptibility and size and on the flow rate. 2.8 and 4.5 ?m superparamagnetic particles with magnetic susceptibilities of 1.1x10-4 and 1.6x10-4 m3 kg-1, respectively, could be completely separated from each other reproducibly. The separated particles were detected by video observation and also by on-chip laser light scattering. Potential applications of this separation method include sorting of magnetic micro- and nanoparticles as well as magnetically labelled cells.

2006-01-01

117

High-gradient magnetic affinity separation of trypsin from porcine pancreatin  

DEFF Research Database (Denmark)

We introduce a robust and scale-flexible approach to macromolecule purification employing tailor-made magnetic adsorbents and high-gradient magnetic separation technology adapted from the mineral processing industries. Detailed procedures for the synthesis of large quantities of low-cost defined submicron-sized magnetic supports are presented. These support materials exhibit unique features, which facilitate their large-scale processing using high magnetic field gradients, namely sufficiently high magnetization, a relatively narrow particle size distribution and ideal superparamagnetism. Following systematic optimization with respect to activation chemistry, spacer length and ligand density, conditions for preparation of effective high capacity (Q(max) = 120 mg g(-1)) strongly interacting (K-d <0.3 mum) trypsin-binding adsorbents based on immobilized benzamidine were established. In small-scale studies approximate to95% of the endogenous trypsin present in a crude porcine pancreatin feedstock was recovered with a purification factor of approximate to4.1 at the expense of only a 4% loss in a-amylase activity. Efficient recovery of trypsin from the same feedstock was demonstrated at a vastly increased scale using a high-gradient magnetic separation system to capture loaded benzamidine-linked adsorbents following batch adsorption. With the aid of a simple recycle loop over 80% of the initially adsorbed trypsin was recovered in-line with an overall purification factor of approximate to3.5.

Hubbuch, Jürgen; Thomas, Owen R. T.

2002-01-01

118

Development of 5 T NbTi Superconducting Magnet with 160 mm Warm Bore for Magnetic Separation  

International Nuclear Information System (INIS)

A wide-bore 5 T NbTi superconducting magnet, for magnetic separator, with an operational current of 106 A is designed and fabricated. This magnet with a oe 60 mm room-temperature bore is installed in a vacuum cryostat and immersed in liquid helium. A two-stage 4 K Gifford-McMahon (GM) cryocooler is used to maintain the cooling shield at 70 K and the condenser at 4 K in order to achieve the zero vaporization loss of liquid helium. The cooling power of the GM cryocooler is 1.5 W. In this paper, the design, heat leakage, stress analysis, quench protection characteristics and preliminary test results are presented.

2008-10-01

119

2D modeling and preliminary in vitro investigation of a prototype high gradient magnetic separator for biomedical applications.  

Science.gov (United States)

High gradient magnetic separation (HGMS) of magnetic materials from fluids or waste products has many established industrial applications. However, there is currently no technology employing HGMS for ex-vivo biomedical applications, such as for the removal of magnetic drug- or toxin-loaded spheres from the human blood stream. Importantly, human HGMS applications require special design modifications as, in contrast to conventional use where magnetic elements are permanently imbedded within the separation chambers, medical separators need to avoid direct contact between the magnetic materials and blood to reduce the risk of blood clotting and to facilitate convenient and safe treatment access for many individuals. We describe and investigate the performance of a magnetic separator prototype designed for biomedical applications. First, the capture efficiency of a prototype HGMS separator unit consisting of a short tubing segment and two opposing magnetizable fine wires along the outside of the tubing was investigated using 2D mathematical modeling. Second, the first-pass effectiveness to remove commercially available, magnetic polystyrene spheres from human blood using a single separator unit was experimentally verified. The theoretical and experimental data correlated well at low flow velocities (0.05 T). This prototype separator unit removed >90% in a single pass of the magnetic spheres from water at mean flow velocity ethylene glycol-water solutions) at mean flow velocity < or =2.0 cm/s. In summary, we describe and prove the feasibility of a HGMS separator for biomedical applications. PMID:17400018

Chen, Haitao; Kaminski, Michael D; Rosengart, Axel J

2007-03-30

120

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

UK PubMed Central (United Kingdom)

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.

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

2012-07-01

 
 
 
 
121

Separation of true fat and water images by correcting magnetic field inhomogeneity in situ.  

UK PubMed Central (United Kingdom)

Dixon's method of chemical shift imaging of a two-component system is modified and extended without requiring additional imaging time. The modified method allows one to obtain truly segregated fat and water images of animal tissues. This is accomplished by acquiring additional image data from which information about in situ magnetic field inhomogeneity and bulk magnetic susceptibility can be derived. Applications to various anatomic sections of the normal human body are illustrated. The method is compared with the standard Dixon technique of chemical shift image separation.

Yeung HN; Kormos DW

1986-06-01

122

Separation of true fat and water images by correcting magnetic field inhomogeneity in situ.  

Science.gov (United States)

Dixon's method of chemical shift imaging of a two-component system is modified and extended without requiring additional imaging time. The modified method allows one to obtain truly segregated fat and water images of animal tissues. This is accomplished by acquiring additional image data from which information about in situ magnetic field inhomogeneity and bulk magnetic susceptibility can be derived. Applications to various anatomic sections of the normal human body are illustrated. The method is compared with the standard Dixon technique of chemical shift image separation. PMID:3704157

Yeung, H N; Kormos, D W

1986-06-01

123

Separation of true fat and water images by correcting magnetic field inhomogeneity in-situ  

Energy Technology Data Exchange (ETDEWEB)

Dixon's method of chemical shift imaging of a two-component system is modified and extended without requiring additional imaging time. The modified method allows one to obtain truly segregated fat and water images of animal tissues. This is accomplished by acquiring additional image data from which information about in situ magnetic field inhomogeneity and bulk magnetic susceptibility can be derived. Applications to various anatomic sections of the normal human body are illustrated. The method is compared with the standard Dixon technique of chemical shift image separation.

Yeung, H.N.; Kormos, D.W.

1986-06-01

124

Separation of true fat and water images by correcting magnetic field inhomogeneity in-situ  

International Nuclear Information System (INIS)

Dixon's method of chemical shift imaging of a two-component system is modified and extended without requiring additional imaging time. The modified method allows one to obtain truly segregated fat and water images of animal tissues. This is accomplished by acquiring additional image data from which information about in situ magnetic field inhomogeneity and bulk magnetic susceptibility can be derived. Applications to various anatomic sections of the normal human body are illustrated. The method is compared with the standard Dixon technique of chemical shift image separation

1986-12-05

125

Electric arc furnace dust treatment: investigation on mechanical and magnetic separation methods.  

Science.gov (United States)

Electric arc furnace dust (EAFD) is a major issue for processing technologies: Several million tons per year are generated, it contains both valuable and hazardous metals and yet no available treatment process has proven to be superior to all others. Processes currently applied or being developed are either of hydro- or pyrometallurgical type, which are very costly. In the paper testing of some physical separation methods of electric arc furnace dust from Polish steel industry were investigated. SEM, EDX analyses as well as grain size observations of dust particles were additionally performed. All investigations confirmed a possibility of effective magnetic and mechanical separation of EAFD particles. PMID:11720260

Sekula, R; Wnek, M; Selinger, A; Wróbel, M

2001-08-01

126

Electric arc furnace dust treatment: investigation on mechanical and magnetic separation methods.  

UK PubMed Central (United Kingdom)

Electric arc furnace dust (EAFD) is a major issue for processing technologies: Several million tons per year are generated, it contains both valuable and hazardous metals and yet no available treatment process has proven to be superior to all others. Processes currently applied or being developed are either of hydro- or pyrometallurgical type, which are very costly. In the paper testing of some physical separation methods of electric arc furnace dust from Polish steel industry were investigated. SEM, EDX analyses as well as grain size observations of dust particles were additionally performed. All investigations confirmed a possibility of effective magnetic and mechanical separation of EAFD particles.

Sekula R; Wnek M; Selinger A; Wróbel M

2001-08-01

127

High efficiency X-band magnetically insulated line oscillator with a separate cathode  

Science.gov (United States)

An X-band magnetically insulated line oscillator (MILO) with a separate cathode has been proposed in order to improve microwave output characteristics. The separate cathode consists of three parts with gradually decreased radii, which are divided by two deep grooves, and only partial cathode surfaces are allowed to emit electrons. In particle-in-cell simulation, high-power microwave with a power of 6.9 GW, frequency of 9.26 GHz, and efficiency of 20.6% is generated, compared with that of 12.2% obtained in a conventional cathode X-band MILO, and the power ratio of the output transverse-electromagnetic mode to transverse-magnetic (TM01) mode is increased from 4 to 27.

Xiao, Renzhen; Song, Wei; Song, Zhimin; Sun, Jun; Shao, Hao; Chen, Changhua

2010-04-01

128

Single-step synthesis and magnetic separation of graphene and carbon nanotubes in arc discharge plasmas.  

UK PubMed Central (United Kingdom)

The unique properties of graphene and carbon nanotubes made them the most promising nanomaterials attracting enormous attention, due to the prospects for applications in various nanodevices, from nanoelectronics to sensors and energy conversion devices. Here we report on a novel deterministic, single-step approach to simultaneous production and magnetic separation of graphene flakes and carbon nanotubes in an arc discharge by splitting the high-temperature growth and low-temperature separation zones using a non-uniform magnetic field and tailor-designed catalyst alloy, and depositing nanotubes and graphene in different areas. Our results are very relevant to the development of commercially-viable, single-step production of bulk amounts of high-quality graphene.

Volotskova O; Levchenko I; Shashurin A; Raitses Y; Ostrikov K; Keidar M

2010-10-01

129

Satellite Observations of Separator Line Geometry of Three-Dimensional Magnetic Reconnection  

CERN Document Server

Detection of a separator line that connects magnetic nulls and the determination of the dynamics and plasma environment of such a structure can improve our understanding of the three-dimensional (3D) magnetic reconnection process. However, this type of field and particle configuration has not been directly observed in space plasmas. Here we report the identification of a pair of nulls, the null-null line that connects them, and associated fans and spines in the magnetotail of Earth using data from the four Cluster spacecraft. With di and de designating the ion and electron inertial lengths, respectively, the separation between the nulls is found to be ~0.7di and an associated oscillation is identified as a lower hybrid wave with wavelength ~ de. This in situ evidence of the full 3D reconnection geometry and associated dynamics provides an important step toward to establishing an observational framework of 3D reconnection.

Xiao, C J; Pu, Z Y; Ma, Z W; Zhao, H; Zhou, G P; Wang, J X; Kivelson, M G; Fu, S Y; Liu, Z X; Zong, Q G; Dunlop, M W; Glassmeier, K-H; Lucek, E; Reme, H; Dandouras, I; Escoubet, C P

2007-01-01

130

Nuclear charge and isobar separation in a gas-filled enge split-pole magnetic spectrograph  

International Nuclear Information System (INIS)

[en] The sepration technique is based on the fact that charge-changing processes of an ion in a gas, if they occur frequently enough in a magnetic field region, lead to trajectories determined by the average charge state of the ion in the gas. The technique has been used to separate isobaric 58Ni and 58Fe ions. 7 refs., 4 figs., 1 tab

1985-01-01

131

Separation into two contributions of stress anneal induced magnetic anistropy in metallis glass ribbons  

Science.gov (United States)

Stress annealing experiments followed by stress relief experiments on metallic glass ribbons have made it possible quantitatively to separate the stress anneal induced magnetic anistropy Ku into two terms of opposite sign, Kan and Kpl These terms, labelled aneslastic and plastic, respectively, show very different dependence on the annealing conditions. The measurements of Ku of iether sign were made possible by use of the small signal inverse Wiedemann effect in twisted ribbons as recently decribed.

Nielsen, O. V.

1983-04-01

132

Trace element distribution patterns in magnetically separated fractions of fracture filling material  

Energy Technology Data Exchange (ETDEWEB)

The distribution patterns of trace elements in magnetically separated fractions of a granite fracture filling material have been studied using instrumental neutron activation analysis. The distribution patterns of trace elements with similar ionic radii and the same charge, Fe-Co, Rb-Cs, Hf-Zr, U-Th, and light REE, were found to be similar. Whereas most of the elements are found in higher concentrations in the more clay rich fractions, Rb and Cs display a more homogeneous distribution.

Cui, D.; Eriksen, T.E. [Royal Inst. of Tech., Stockholm (Sweden)

1996-08-01

133

Vertically coupled non-uniform quantum rings with two separated electrons in threading magnetic field  

International Nuclear Information System (INIS)

We propose a simple method for calculating the energy spectrum of two separated electrons in vertically coupled narrow quantum rings with non-uniform cross-sections heights. We present numerical results for energies of some low-lying levels as a function of the magnetic flux for a particular case, in which one of two rings is uniform and other has a locally distorted height. The effect of the distortion on the Aharonov-Bohm oscillations is studied.

2010-09-01

134

Spin-Charge Separation in Two-dimensional Frustrated Quantum Magnets  

CERN Multimedia

The dynamics of a mobile hole in two-dimensional frustrated quantum magnets is investigated by exact diagonalization techniques. Our results provide evidence for spin-charge separation upon doping the kagome lattice, a prototype of a spin liquid. In contrast, in the checkerboard lattice, a symmetry broken Valence Bond Crystal, a small quasi-particle peak is seen for some crystal momenta, a finding interpreted as a restoration of weak holon-spinon confinement.

Laeuchli, A

2004-01-01

135

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

UK PubMed Central (United Kingdom)

Porous/magnetic molecularly imprinted polymers (PM-MIPs) were prepared by a 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 crosslinked 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 (Ms = 0.7448 emu g(-1) ), 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 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. This article is protected by copyright. All rights reserved.

Hang H; Li C; Pan J; Li L; Dai J; Dai X; Yu P; Feng Y

2013-07-01

136

Design and analysis of beam separator magnets for third generation aberration compensated PEEMs  

International Nuclear Information System (INIS)

[en] A state of the art X-ray photoemission electron microscope (PEEM2) is operational at the Advanced Light Source at a resolution of typically 50 nm for a range of chemical and magnetic surface studies. A new microscope, PEEM3, is under development with an aim of achieving a resolution of 5 nm and more than an order of magnitude increase in transmission at the nominal resolution of PEEM2. The resolution and flux improvement is realized by providing geometric and chromatic aberration compensations in the system using an electron mirror and a beam separator magnet. The nearly aberration-free design of the beam separator is critical to the performance of third generation PEEMs. In this paper, we present the optics design model, optimal operation parameters, analyses of aberration impact, as well as the mechanical alignment tolerance for PEEM3 separator prototypes. In particular, we emphasize the importance of a new semi-analytical approach to design complex charged particle optics using the truncated power series algebra. Because of its ability to compute high-order aberrations, this approach allows systematic and comprehensive analyses of any charged particle optics systems with analytical electric and magnetic fields

2004-02-21

137

Recover vigorous cells of Magnetospirillum magneticum AMB-1 by capillary magnetic separation  

Science.gov (United States)

Cultivable magnetotactic bacteria (MTB) in laboratory can provide sufficient samples for molecular microbiological and magnetic studies. However, a cold-stored MTB strain, such as Magnetospirillum magneticum AMB-1, often loses its ability to synthesize magnetosomes and consequently fails to sense the external magnetic field. It is therefore important to quickly recover vigorous bacteria cells that highly capable of magnetosome producing. In this study, a modified capillary magnetic separation system was designed to recover a deteriorating strain of Magnetospirillum magneticum AMB-1 that long-term cold-stored in a refrigerator. The results show that all cells obtained after a 3-cycle treatment were vigorous and had the ability to produce magnetosomes. Moreover, the 3rd-cycle recovered cells were able to form more magnetosome crystals. Compared with the colony formation method, this new method is time-saving, easily operated, and more efficient for recovering vigorous MTB cells.

Li, Jinhua; Ge, Xin; Zhang, Xiaokui; Chen, Guanjun; Pan, Yongxin

2010-07-01

138

Preconcentration and separation of ultra-trace beryllium using quinalizarine-modified magnetic microparticles  

Energy Technology Data Exchange (ETDEWEB)

Magnetically-assisted chemical separation/preconcentration method for the analysis of beryllium from aqueous solutions was developed. According to this method several extractants were coated on certain magnetic microparticles to assist the extraction of beryllium from the aqueous solutions. The influence of different parameters (type and amount of extractant, pH, equilibrium time and ionic strength) was investigated. Also, the interfering effect of various cationic and anionic species on the percent recovery of beryllium was studied. The applied spectrophotometric method showed good linearity and precision at a given wavelength (605.0 nm). Among the extractants used, quinalizarine resulted in almost a full recovery of beryllium at pH 7.4, which was the optimum extraction pH. The equilibrium time of the extraction was 10.0 min. The quantitative re-extraction was carried out by 0.5 M nitric acid. Also, the stability of the extractant-coated magnetic microparticles was 4 cycles (extraction and re-extraction) and the used magnetic microparticles showed good selectivity for beryllium against other cations and anions. Finally, the developed method was applicable for the preconcentration and separation of beryllium from spring water, tap water and certified reference waters. The obtained detection limit was 30 ng L{sup -1}.

Ashtari, Parviz, E-mail: pashtari@aeoi.org.ir [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Center, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); NFCS, Nuclear Science and Technology Research Institute, PO Box 11365-8486, Tehran (Iran, Islamic Republic of); Wang Kemin; Yang Xiaohai [State Key Laboratory of Chemo/Biosensing and Chemometrics, Biomedical Engineering Center, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Ahmadi, Seyed Javad [NFCS, Nuclear Science and Technology Research Institute, PO Box 11365-8486, Tehran (Iran, Islamic Republic of)

2009-07-30

139

Recovery of iron from vanadium tailings with coal-based direct reduction followed by magnetic separation.  

UK PubMed Central (United Kingdom)

A technique with coal-based direct reduction followed by magnetic separation is presented in this study for recovering and reusing iron otherwise wasted in vanadium tailings. Process parameters such as usage of additives, tailings/reductant/additives ratio, reduction temperature and time, as well as particle size were experimentally determined. The optimum process parameters were proposed as follows: using lime as the additive, lignite as the reductant, weight ratios of vanadium tailings/lignite/lime at 100:30:10, reduction roasting at 1200 °C for 60 min, and particle size of 98% less than 30 ?m in the final roasted product feeding to magnetic separation. Under these conditions, a magnetic concentrate containing 90.31% total iron and 89.76% metallization iron with a total iron recovery rate of 83.88% was obtained. In addition, mineralography of vanadium tailings, coal-based reduction product and magnetic concentrate were studied by X-ray powder diffraction technique (XRD). The microstructures of above products were analyzed by scanning electron microscope (SEM) to help understand the mechanism.

Yang H; Jing L; Zhang B

2011-01-01

140

Preparation and application of novel magnetically separable ?-Fe2O3/activated carbon sphere adsorbent  

International Nuclear Information System (INIS)

Highlights: ? Magnetic ?-Fe2O3 particles have been successfully in situ fabricated in the FexOy/C composites. ? The as-prepared ?-Fe2O3/C microspheres were the composite of single-phase ?-Fe2O3 and activated carbon material ? The porous ?-Fe2O3/C microspheres as sorbent exhibited high adsorption efficiency and high capacity towards methyl orange. - Abstract: Magnetic ?-Fe2O3/activated carbon microspheres have been synthesized by an activation process of carbon microspheres containing iron oxides, which were prepared by hydrothermal method. The structure and morphology of the magnetic porous carbon microspheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), thermogravimetry and differential thermal analysis (TG-DTA) and N2 adsorption-desorption technique. The results showed that the as-prepared activated carbon spheres were the composite of single-phase ?-Fe2O3 and activated carbon material, and the content of carbon was about 3.87%. Using methyl orange as model pollutant, the magnetic porous carbon microspheres showed good adsorption capacities of 44.65 mg/g. The isotherm evaluations revealed that the Langmuir model attained better fits to the experimental equilibrium data than the Freundlich model. These magnetic porous carbon microspheres could potentially be applied in separation processes.

2011-06-25

 
 
 
 
141

Removal and recycle of phosphate from treated water of sewage plants with zirconium ferrite adsorbent by high gradient magnetic separation  

International Nuclear Information System (INIS)

Zirconium ferrite particles are good adsorbent for phosphate ions. Magnetic separation characteristics for removal of phosphate from treated water of sewage plants with the adsorbent have been studied to prevent eutrophication of semi-enclosed bay, e.g. the bay of Tokyo. Based on the adsorption for the phosphate ions and ferromagnetic properties of the zirconium ferrite adsorbent, high gradient magnetic separation characteristics with using superconducting magnet was discussed. Very rapid magnetic filtration velocity, i.e. 1m/s, and regeneration properties of the adsorbent indicate that the zirconium ferrite is the excellent adsorbent for phosphorus removal and recycle from treated water of large scale sewage plants.

2009-03-01

142

Magnetic particle separation technique: a reliable and simple tool for RIA/IRMA and quantitative PCR assay  

International Nuclear Information System (INIS)

Five types of magnetic particles without or with aldehyde, amino and carboxyl functional groups, respectively were used to immobilize first or second antibody by three models, i. e. physical adsorption, chemical coupling and immuno-affinity, forming four types of magnetic particle antibodies. The second antibody immobilized on polyacrolein magnetic particles through aldehyde functional groups and the first antibodies immobilized on carboxylic polystyrene magnetic particles through carboxyl functional groups were recommended to apply to RIAs and/or IRMAs. Streptavidin immobilized on commercial magnetic particles through amino functional groups was successfully applied to separating specific PCR product for quantification of human cytomegalovirus. In the paper typical data on reliability of these magnetic particle ligands were reported and simplicity of the magnetic particle separation technique was discussed. The results showed that the technique was a reliable and simple tool for RIA/IRMA and quantitative PCR assay. (author)

1998-04-03

143

2D modeling and preliminary in vitro investigation of a prototype high gradient magnetic separator for biomedical applications.  

UK PubMed Central (United Kingdom)

High gradient magnetic separation (HGMS) of magnetic materials from fluids or waste products has many established industrial applications. However, there is currently no technology employing HGMS for ex-vivo biomedical applications, such as for the removal of magnetic drug- or toxin-loaded spheres from the human blood stream. Importantly, human HGMS applications require special design modifications as, in contrast to conventional use where magnetic elements are permanently imbedded within the separation chambers, medical separators need to avoid direct contact between the magnetic materials and blood to reduce the risk of blood clotting and to facilitate convenient and safe treatment access for many individuals. We describe and investigate the performance of a magnetic separator prototype designed for biomedical applications. First, the capture efficiency of a prototype HGMS separator unit consisting of a short tubing segment and two opposing magnetizable fine wires along the outside of the tubing was investigated using 2D mathematical modeling. Second, the first-pass effectiveness to remove commercially available, magnetic polystyrene spheres from human blood using a single separator unit was experimentally verified. The theoretical and experimental data correlated well at low flow velocities (<5.0 cm/s) and high external magnetic fields (>0.05 T). This prototype separator unit removed >90% in a single pass of the magnetic spheres from water at mean flow velocity < or =8.0 cm/s and from blood mimic fluids (ethylene glycol-water solutions) at mean flow velocity < or =2.0 cm/s. In summary, we describe and prove the feasibility of a HGMS separator for biomedical applications.

Chen H; Kaminski MD; Rosengart AJ

2008-01-01

144

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

International Nuclear Information System (INIS)

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.

2010-12-20

145

Selective recognition and separation of nucleosides using carboxymethyl-?-cyclodextrin functionalized hybrid magnetic nanoparticles.  

UK PubMed Central (United Kingdom)

A novel magnetic nanoadsorbent (CMCD-APTS-MNPs) containing the superparamagnetic and molecular recognition properties was synthesized by grafting carboxymethyl-?-cyclodextrin (CM-?-CD) on 3-aminopropyltriethoxysile (APTS) modified Fe(3)O(4) nanoparticles. The feasibility of using CMCD-APTS-MNPs as magnetic nanoadsorbent for selective adsorption of adenosine (A) and guanosine (G) based on inclusion and molecular recognition was demonstrated. The as-synthesized magnetic nanoparticles were characterized by TEM, FTIR and TGA analyses. The effects of pH and initial nucleoside concentrations on the adsorption behavior were studied. The complexation of CMCD-APTS-MNPs with both nucleosides was found to follow the Langmuir adsorption isotherm. The CMCD-APTS-MNPs showed a higher adsorption ability and selectivity for G than A under identical experimental conditions, which results from the ability of selective binding and recognition of the immobilized CM-?-CD towards G. The driving force of the separation between G and A is through the different weak interaction with grafted CM-?-CD, i.e., hydrogen bond interaction, which is evidenced by different inclusion equilibrium constants and FTIR analyses of inclusion complexes between grafted cyclodextrin and the guest molecules. Our results indicated that this nanoadsorbent would be a promising tool for easy, fast and selective separation, analysis of nucleosides and nucleotides in biological samples.

Badruddoza AZ; Junwen L; Hidajat K; Uddin MS

2012-04-01

146

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

International Nuclear Information System (INIS)

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

2000-01-00

147

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

Science.gov (United States)

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

148

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

Energy Technology Data Exchange (ETDEWEB)

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 [Institute of Life Science and Technology, Tongji University, Shanghai 200092 (China); Song Xin [Institute of Life Science and Technology, Tongji University, Shanghai 200092 (China); Cheng Duo [Institute of Life Science and Technology, Tongji University, Shanghai 200092 (China); Liu Shupeng [Institute of Life Science and Technology, Shanghai Jiaotong University, Shanghai 200032 (China); Zhu Jian [Institute of Life Science and Technology, Tongji University, Shanghai 200092 (China)

2006-07-14

149

Magnetic-field-induced nematic-nematic phase separation and droplet formation in colloidal goethite  

International Nuclear Information System (INIS)

[en] We demonstrate the suitability of polarization microscopy to study the recently discovered (parallel) nematic-(perpendicular) nematic phase separation. This novel type of phase transition is induced by applying an external magnetic field to a nematic liquid crystal of boardlike colloidal goethite and is due to an interplay between the intrinsic magnetic properties of goethite and the collective effect of liquid crystal formation. It is shown that the intense ochre colour of goethite does not preclude the use of polarization microscopy and interference colours, and that dichroism can give valuable qualitative information on the nature of the phases, their anchoring and their sedimentation and order parameter profiles. We also apply these techniques to study 'nematic-nematic tactoids': nematic droplets sedimenting within a nematic medium with mutually perpendicular orientations.

2011-05-18

150

Method of separating and enriching phosphated peptide section by metal oxide magnetic micro-sphere  

UK PubMed Central (United Kingdom)

The invention relates to inorganic material and biochemical analysis technology field, more specificly a method of separating and enriching phosphorylated peptide adopting metal oxide magnetic microshpere with core-shell structure. micro sorbent magnetic microshpere is directly added in to mixed solution containing phosphorylated peptide in the present invention for enrich phosphorylated peptide under certain condition. The method is conveniently operated, doesn't need centrifugation, avoid the coprecipitation effect during centrifugation and hole effect of tradition fixed metal ion affinity material and possesses higher chemical inertia and stability. The present method has good selective enriching function for phosphorylated peptide. The enriching efficiency can upgrade a order of magnitude. The enriched sample can be directly analyzed by matrix-assisted laser desorption Ionization-flying time mass spectrogarphy without elution or after elution. The method has practical value in proteome, protein translation-modification field.

DENG CHUNHUI XU

151

Removal of selected hazardous air pollutant precursors by dry magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

Most trace elements in coal are associated with minerals that are removed by the MagMill{trademark} (patent pending). In previous measurements, the authors found significant reductions of major trace elements (mercury, arsenic, selenium, and many others) by dry magnetic separation alone. In recent but separate measurements using a 300 Lb/Hr beta prototype MagMill{trademark}, concentrations of trace elements including mercury, arsenic, selenium, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, thallium, vanadium, and zinc were reduced in the clean coal product and concentrated in the mineral rich fraction removed from the coal. In this paper, the authors report measurements and reductions of sulfur, mineral matter, and trace elements for three US coals--a western Adaville-series coal, an eastern Upper Kittanning coal, and an eastern Pittsburgh seam coal.

Brandner, E.D.; Oder, R.R.; Jamison, R.E.

2000-07-01

152

Magnetically Separable Base Catalysts: Heterogeneous Catalysis vs. Quasi-Homogeneous Catalysis  

Directory of Open Access Journals (Sweden)

Full Text Available The synthesis of magnetically separable quasi-homogeneous base catalyst and heterogeneous base catalyst is described. The quasi-homogeneous catalyst is achieved by supporting silane monomers functionalized with different amine groups directly on the surface of magnetite nanoparticles. The heterogeneous catalyst is prepared via a sol-gel process in which silane monomers containing different amine groups are copolymerized with tetraethoxysilane in the presence of magnetite nanoparticles functionalized with ionic liquid moieties. The reactivity of the quasi-homogeneous and the heterogeneous base catalysts is compared in the nitroaldol condensation.

Raed Abu-Reziq; Howard Alper

2012-01-01

153

Magnetic dipole excitation mode according to the collective model with separate neutron and proton deformations  

Energy Technology Data Exchange (ETDEWEB)

The collective model with separate neutron and proton deformations is developed. The collective motion of individual neutron and proton surfaces is reduced to the motion of the mass surface and the neutron skin. The strong coupling scheme of the neutron skin vibrations to the mass-surface motion is applied for well-deformed nuclei. The magnetic dipole excitation mode, which was discovered experimentally, is explained as the K=1 one-phonon neutron skin vibration in a deformed nucleus. Some estimates of parameters of the model are performed. Finally, the model is confronted with the two-rotor model and the interacting boson model (IBM-2).

Rohozinski, S.G.; Greiner, W.

1985-09-01

154

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

Energy Technology Data Exchange (ETDEWEB)

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

155

Synthesis of teicoplanin-modified hybrid magnetic mesoporous silica nanoparticles and their application in chiral separation of racemic compounds.  

UK PubMed Central (United Kingdom)

Teicoplanin-conjugated mesoporous silica magnetic nanoparticles (TE-MSMNPs) were fabricated as novel chiral magnetic nano-selectors. Successful preparation of the functional magnetic mesoporous materials was achieved by grafting teicoplanin on N-(2-aminoethyl)-3-aminopropyltrimethoxysilane-modified mesoporous silica Fe3O4 magnetic nanoparticles (AEAPTMS-MSMNPs), and this was confirmed by various characterization techniques. The synthesized magnetic nanoparticles were regularly spherical and uniformly mesoporous with an average diameter of around 600 nm and a mean pore size of about 3.9 nm, respectively. These versatile magnetic nanoparticles were effective in a direct chiral separation of five racemic compounds in phosphate buffer. Much stronger interactions were observed with the (+)-enantiomers than with the (-)-enantiomers. After washing with water and ethanol by sonication, TE-MSMNPs could be reused at least three times with little efficiency loss. The functional magnetic mesoporous nanoparticles were easily separated from the racemic solutions using an external magnetic field. These magnetic nano-materials are suitable for enantiomer separations.

Wu J; Su P; Huang J; Wang S; Yang Y

2013-06-01

156

Development program for magnetically assisted chemical separation: Evaluation of cesium removal from Hanford tank supernatant  

International Nuclear Information System (INIS)

Magnetic particles (MAG*SEPSM) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEPSM particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEPSM particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEPSM particles with a gamma dose equivalent to 100 cycles of use. This irradiation decreased the loading capacity and distribution ratios for the particles by greater than 75%. The particles demonstrated high sensitivity to radiolytic damage due to the degradation of the polymeric regions. These results were supported by optical microscopy measurements. Overall, use of magnetic particles for cesium separation under nuclear waste conditions was found to be marginally effective

1994-01-01

157

Magnetic separation of encapsulated islet cells labeled with superparamagnetic iron oxide nano particles.  

UK PubMed Central (United Kingdom)

Islet cell transplantation is a promising option for the restoration of normal glucose homeostasis in patients with type 1 diabetes. Because graft volume is a crucial issue in islet transplantations for patients with diabetes, we evaluated a new method for increasing functional tissue yield in xenogeneic grafts of encapsulated islets. Islets were labeled with three different superparamagnetic iron oxide nano particles (SPIONs; dextran-coated SPION, siloxane-coated SPION, and heparin-coated SPION). Magnetic separation was performed to separate encapsulated islets from the empty capsules, and cell viability and function were tested. Islets labeled with 1000 ?g Fe/ml dextran-coated SPIONs experienced a 69.9% reduction in graft volume, with a 33.2% loss of islet-containing capsules. Islets labeled with 100 ?g Fe/ml heparin-coated SPIONs showed a 46.4% reduction in graft volume, with a 4.5% loss of capsules containing islets. No purification could be achieved using siloxane-coated SPIONs due to its toxicity to the primary islets. SPION labeling of islets is useful for transplant purification during islet separation as well as in vivo imaging after transplantation. Furthermore, purification of encapsulated islets can also reduce the volume of the encapsulated islets without impairing their function by removing empty capsules.

Mettler E; Trenkler A; Feilen PJ; Wiegand F; Fottner C; Ehrhart F; Zimmermann H; Hwang YH; Lee DY; Fischer S; Schreiber LM; Weber MM

2013-07-01

158

A chemically functionalized magnetic nanoplatform for rapid and specific biomolecular recognition and separation.  

UK PubMed Central (United Kingdom)

We have developed a target-molecule-functionalized magnetic nanoparticle (MNP)-based method to facilitate the study of biomolecular recognition and separation. The superparamagnetic property of MNPs allows the corresponding biomolecules to be rapidly separated from crude biofluids with a significant improvement in recovery yield and specificity. Various MNPs functionalized with tag molecules (chitin, heparin, and amylose) were synthesized for recombinant protein purification, and several probe-functionalized MNPs, such as nitrilotriacetic acid (NTA)@MNP and P(k)@MNP, exhibited excellent extraction efficiency for proteins. In a cell recognition study, mannose-functionalized MNPs allowed specific purification of Escherichia coli with FimH adhesin on the surface. In an immunoprecipitation assay, the antibody-conjugated MNPs reduced the incubation time from 12 to 1 h while maintaining a comparable efficiency. The functionalized MNPs were also used in a membrane proteomic study that utilized the interaction between streptavidin-functionalized MNPs and biotinylated cell membrane proteins. Overall, the functionalized MNPs were demonstrated to be promising probes for the specific separation of targets from proteins to cells and proteomics.

Lin PC; Yu CC; Wu HT; Lu YW; Han CL; Su AK; Chen YJ; Lin CC

2013-01-01

159

Wave-driven rotation and mass separation in rotating magnetic mirrors  

Science.gov (United States)

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.

160

Recovering metals from red mud by thermal treatment and magnetic separation  

Science.gov (United States)

This paper deals with an alternative treatment for recovering metals from goethite red mud (RM), which occurs as a by-product at zinc leaching plants. It is derived from the hydrometallurgical treatment of sphalerite, which involves roasting followed by acid attack and subsequent recovery of the zinc by electrodeposition. The leaching mud contains various oxides and hydroxides of iron plus lesser amounts of sulfates of Pb, Zn, Ca, Cd, Ag, In, Se, and other metals. In recent years, numerous attempts have been made to recover the RM or render it inert, particularly by such processes as vitrification or lithification for the production of glass ceramics. The work reported here proposes a treatment involving reduction and magnetic separation to permit the extraction of pure zinc, a high percentage of a pure magnetite, and a harmless slag containing mixed silicates of zinc and lead as well as oxides of minor elements.

Plescia, Paolo; Maccari, Dante

1996-01-01

 
 
 
 
161

Blind Source Separation of Hemodynamics from Magnetic Resonance Perfusion Brain Images Using Independent Factor Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Perfusion magnetic resonance brain imaging induces temporal signal changes on brain tissues, manifesting distinct blood-supply patterns for the profound analysis of cerebral hemodynamics. We employed independent factor analysis to blindly separate such dynamic images into different maps, that is, artery, gray matter, white matter, vein and sinus, and choroid plexus, in conjunction with corresponding signal-time curves. The averaged signal-time curve on the segmented arterial area was further used to calculate the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT). The averaged ratios for rCBV, rCBF, and MTT between gray and white matters for normal subjects were congruent with those in the literature.

Yen-Chun Chou; Chia-Feng Lu; Wan-Yuo Guo; Yu-Te Wu

2010-01-01

162

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

Science.gov (United States)

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

2013-04-24

163

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

UK PubMed Central (United Kingdom)

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.

Tang W; Su Y; Li Q; Gao S; Shang JK

2013-07-01

164

Preparation and characterization of a magnetically separated photocatalyst and its catalytic properties  

International Nuclear Information System (INIS)

A kind of loaded photocatalyst of TiO2/?-Fe2O3 (TF) that can photodegrade organic pollutants in the dispersion system effectively and can be recycled easily by a magnetic field is reported in this paper. The structural features of TF catalyst sintered at different temperatures (in the range 200-900 deg. C) have been investigated by X-ray diffraction, atomic force microscope and transmission electron microscope studies. Phase composition and crystallinity change with the increasing sintering temperature of the specimens. The TF photocatalyst is composed of two parts: (1) TiO2 shell used for photocatalysis; (2) ?-Fe2O3 core for separation by the magnetic field. Due to the strong light absorption by ?-Fe2O3, when the amount of the loaded TiO2 content was under 30% in the catalyst, the photocatalytic activity of TF was significantly lower than that of the pure TiO2. On the other hand, the photocatalytic activity of TF reduced to a large extent at high sintering temperature (900 deg. C) owing to the presence of inactive (Fe2TiO5) pseudobrokite phase. The sample sintered at 500 deg. C showed the highest activity for the degradation of aqueous solution of acridine dye.

2003-04-29

165

Preconcentration and separation of ultra-trace palladium ion using pyridine-functionalized magnetic nanoparticles  

International Nuclear Information System (INIS)

We present a study on the application of magnetic nanoparticles (MNPs) prepared from Fe3O4 and functionalized with pyridine as an adsorbent for the solid-phase extraction of trace quantities of Pd(II) ion. The pyridine group was immobilized on the surface of the MNPs by covalent bonding of isonicotinamide. The modified MNPs can be readily separated from an aqueous solution by applying an external magnetic field. Effects of pH, the amount of functionalized MNPs, extraction time, type and quantity of eluent, desorption time, break-through volume and interfering ions on the extraction efficiency were optimized. The amount of Pd(II) was then determined using FAAS. Under the optimized conditions, the detection limit and preconcentration factor are 0.15 ?g L-1 and 196, respectively, and the relative standard deviation (at 20 ?gL-1; for n=10) is 3.7 %. The method had a linear analytical range from 1 to 80 ?g L-1 and was applied to determine Pd(II) in spiked tape water and soil. (author)

2012-01-01

166

Optimized high gradient magnetic separation for isolation of Plasmodium-infected red blood cells  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Highly purified infected red blood cells (irbc), or highly synchronized parasite cultures, are regularly required in malaria research. Conventional isolation and synchronization rely on density and osmotic fragility of irbc, respectively. High gradient magnetic separation (HGMS) offers an alternative based on intrinsic magnetic properties of irbc, avoiding exposure to chemicals and osmotic stress. Successful HGMS concentration in malaria research was previously reported using polymer coated columns, while HGMS depletion has not been described yet. This study presents a new approach to both HGMS concentration and depletion in malaria research, rendering polymer coating unnecessary. Methods A dipole magnet generating a strong homogenous field was custom assembled. Polypropylene syringes were fitted with one-way stopcocks and filled with stainless steel wool. Rbc from Plasmodium falciparum cultures were resuspended in density and viscosity optimized HGMS buffers and HGMS processed. Purification and depletion results were analysed by flow cytometer and light microscopy. Viability was evaluated by calculating the infection rate after re-culturing of isolates. Results In HGMS concentration, purity of irbc isolates from asynchronous cultures consistently ranged from 94.8% to 98.4% (mean 95.7%). With further optimization, over 90% of isolated irbc contained segmented schizonts. Processing time was less than 45 min. Reinfection rates ranged from 21.0% to 56.4%. In HGMS depletion, results were comparable to treatment with sorbitol, as demonstrated by essentially identical development of cultures. Conclusion The novel HGMS concentration procedure achieves high purities of segmented stage irbc from standard asynchronous cultures, and is the first HGMS depletion alternative to sorbitol lysis. It represents a simple and highly efficient alternative to conventional irbc concentration and synchronization methods.

Bhakdi Sebastian C; Ottinger Annette; Somsri Sangdao; Sratongno Panudda; Pannadaporn Peeranad; Chimma Pattamawan; Malasit Prida; Pattanapanyasat Kovit; Neumann Hartmut PH

2010-01-01

167

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

International Nuclear Information System (INIS)

[en] A novel method is described for the preparation of superparamagnetic mesoporous maghemite (?-Fe2O3)/silica (SiO2) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe3O4) 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 Fe3O4 to ?-Fe2O3 by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 deg. 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 m2/g), and mesoporosity (dpore=6.62 nm). The composite microsphere consists of interlocked amorphous SiO2 nanoparticles, in which cubic ?-Fe2O3 nanocrystals are homogeneously dispersed and thermally stable against ?- to ?-phase transformation at temperatures up to 600 deg. 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.

2010-01-01

168

Preliminary results of pre-combustion removal of mercury, arsenic, and selenium from coal by dry magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The authors report the results of preliminary measurements of pre-combustion separation of major metal oxides and trace elements from coal by dry magnetic separation. The measurements have been made as part of ETCi's development of MagMill{trademark} technology for removing mineral matter from coal at the pulverizer at the front end of a coal fired power plant. The technology is specific to separation of mercury, arsenic, and selenium because of their associations with iron pyrites in coal. Measurements were made on a suite of five Eastern US and five Illinois Basin bituminous rank coals prepared at 8 Mesh topsize and processed as 8 Mesh by zero fractions through a dry Para Trap Magnetic Separator. Measurements of major metals and trace elements were made on the feed coal, the magnetic refuse fraction and the magnetic clean coal product. The range of weight recoveries measured for 13 of the trace elements for the suite of coals indicates a significant potential for pre-combustion removal of trace elements and especially for mercury, selenium, and arsenic by dry magnetic methods. While these three elements are important because they are considered hazardous air pollutant precursors, pre-combustion removal of arsenic is especially important because of its role in poisoning catalysts used in emerging SO{sub x} and NO{sub x} control technologies.

Oder, R.R.; Jamison, R.E.; Brandner, E.D.

1999-07-01

169

Polydopamine-based molecular imprinting on silica-modified magnetic nanoparticles for recognition and separation of bovine hemoglobin.  

UK PubMed Central (United Kingdom)

Surface molecular imprinting, especially on the surface of silica-modified magnetic nanoparticles, has been proposed as a promising strategy for protein recognition and separation. Inspired by the self-polymerization of dopamine, we synthesized a polydopamine-based molecular imprinted film coating on silica-Fe(3)O(4) nanoparticles for recognition and separation of bovine hemoglobin (BHb). Magnetic molecularly imprinted nanoparticles (about 860 nm) possess a core-shell structure. Magnetic molecularly imprinted nanoparticles (MMIP) show a relatively high adsorption capacity (4.65 ± 0.38 mg g(-1)) and excellent selectivity towards BHb with a separation factor of 2.19. MMIP with high saturation magnetization (10.33 emu g(-1)) makes it easy to separate the target protein from solution by an external magnetic field. After three continuous adsorption and elution processes, the adsorption capacity of MMIP remained at 4.30 mg g(-1). Our results suggest that MMIPs are suitable for the removal of high abundance of protein and the enrichment of low abundance of protein in proteomics.

Jia X; Xu M; Wang Y; Ran D; Yang S; Zhang M

2013-01-01

170

Polydopamine-based molecular imprinting on silica-modified magnetic nanoparticles for recognition and separation of bovine hemoglobin.  

Science.gov (United States)

Surface molecular imprinting, especially on the surface of silica-modified magnetic nanoparticles, has been proposed as a promising strategy for protein recognition and separation. Inspired by the self-polymerization of dopamine, we synthesized a polydopamine-based molecular imprinted film coating on silica-Fe(3)O(4) nanoparticles for recognition and separation of bovine hemoglobin (BHb). Magnetic molecularly imprinted nanoparticles (about 860 nm) possess a core-shell structure. Magnetic molecularly imprinted nanoparticles (MMIP) show a relatively high adsorption capacity (4.65 ± 0.38 mg g(-1)) and excellent selectivity towards BHb with a separation factor of 2.19. MMIP with high saturation magnetization (10.33 emu g(-1)) makes it easy to separate the target protein from solution by an external magnetic field. After three continuous adsorption and elution processes, the adsorption capacity of MMIP remained at 4.30 mg g(-1). Our results suggest that MMIPs are suitable for the removal of high abundance of protein and the enrichment of low abundance of protein in proteomics. PMID:23175702

Jia, Xiaoping; Xu, Minli; Wang, Yuzhi; Ran, Dan; Yang, Shan; Zhang, Min

2013-01-21

171

Comparison of the in vitro invasive capabilities of Plasmodium falciparum schizonts isolated by Percoll gradient or using magnetic based separation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Percoll gradient centrifugation is often used for synchronization, enrichment, or isolation of a particular stage of Plasmodium falciparum. However, Percoll, a hyperosmotic agent, may have harmful effects on the parasites. Magnetic bead column (MBC) separation has been used as an alternative. This is a report of a head-to-head comparison of the in vitro invasive capabilities of parasites isolated by either of the two methods. Methods The P. falciparum laboratory strain isolate 7G8 was grown in vitro using standard procedures and synchronized using 5% sorbitol. On separate days when the schizont parasitaemia was >1%, the culture was split and half was processed by Percoll gradient centrifugation and the other half by magnetic bead column separation. Both processed parasites were placed back in culture and allowed to invade new uninfected erythrocytes. Results In 10 paired assays, the mean efficiency of invasion of 7G8 parasites treated by Percoll gradient centrifugation was 35.8% that of those treated by magnetic bead column separation (95% CI, p = 0.00067) A paired t test with two tails was used for these comparisons. Conclusions In this comparison, magnetic bead column separation of 7G8 schizonts resulted in higher viability and efficiency of invasion than utilizing Percoll gradient centrifugation.

Spadafora Carmenza; Gerena Lucia; Kopydlowski Karen M

2011-01-01

172

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

UK PubMed Central (United Kingdom)

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.

Abd Aziz A; Yong KS; Ibrahim S; Pichiah S

2012-01-01

173

Actinide separation of high level waste using solvent extractants on magnetic microparticles  

International Nuclear Information System (INIS)

Polymer-coated ferromagnetic particles with an absorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted by tributyl phosphate (TBP) are being evaluated for application in the separation and the recovery of low concentrations of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can be recovered from the waste solution using a magnet. Chemical characterization of the extractant-absorbed particles from simulated solutions and various nitric acid solutions was performed by gamma and liquid scintillation counting of plutonium and americium. The concentration range is 0.01M HNO3 to 6M HNO3. The actinide partition constant (Kd) at 2M HNO3 was determined to be between 3000 and 30,000, which is larger than those projected for actinides recovered by additional liquid/liquid extraction. Results from transmission electron microscopy (TEM) indicated a large dependence of Kd on relative magnetite location within the polymer and the polymer surface area. Monitoring the simulated waste solutions by inductively coupled plasma (ICP) analysis demonstrated that magnetite dissolution was 4% after 2 weeks in 5M HNO3. Energy disperse spectroscopy (EDS) demonstrated homogeneous metal complexation on the polymer surface with no metal clustering. The radiolytic stability of the particles was studied using 60Co gamma irradiation under various conditions. The results showed that Kd more strongly depends on the nitric acid dissolution rate of the magnetite than the gamma irradiation dose. Results of actinide separation from simulated high level waste representative of that at various DOE sites are discussed.

1994-01-01

174

The Vlasov equation with strong magnetic field and oscillating electric field as a model of isotope resonant separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We study qualitative behavior of the Vlasov equation with strong external magnetic field and oscillating electric field. This model is relevant in order to understand isotop resonant separation. We show that the effective equation is a kinetic equation with a memory term. This memory term involves a...

Frenod, Emmanuel; Watbled, Frederique

175

Separation of Water and Fat Signal in Magnetic Resonance Imaging : Advances in Methods Based on Chemical Shift  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnetic resonance imaging (MRI) is one of the most important diagnostic tools of modern healthcare. The signal in medical MRI predominantly originates from water and fat molecules. Separation of the two components into water-only and fat-only images can improve diagnosis, and is the premier non-inv...

Berglund, Johan

176

A Phos-tag-based magnetic-bead method for rapid and selective separation of phosphorylated biomolecules.  

Science.gov (United States)

A simple and efficient method based on magnetic-bead technology has been developed for the separation of phosphorylated and nonphosphorylated low-molecular-weight biomolecules, such as nucleotides, phosphorylated amino acids, or phosphopeptides. The phosphate-binding site on the bead is an alkoxide-bridged dinuclear zinc(II) complex with 1,3-bis(pyridin-2-ylmethylamino)propan-2-olate (Phos-tag), which is linked to a hydrophilic cross-linked agarose coating on a magnetic core particle. All steps for the phosphate-affinity separation are conducted in buffers of neutral pH with 50 ?L of the magnetic beads in a 1.5-mL microtube. The entire separation protocol for phosphomonoester-type compounds, from addition to elution, requires less than 12 min per sample if the buffers and the zinc(II)-bound Phos-tag magnetic beads have been prepared in advance. The phosphate-affinity magnetic beads are reusable at least 15 times without a decrease in their phosphate-binding ability and they are stable for three months in propan-2-ol. PMID:23523882

Tsunehiro, Masaya; Meki, Yuma; Matsuoka, Kanako; Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

2013-03-08

177

Separation of species of a binary fluid mixture confined in a channel in presence of a strong transverse magnetic field  

Directory of Open Access Journals (Sweden)

Full Text Available Effects of a transverse magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids confined between two stationary parallel plates are examined. Both the plates are maintained at constant temperatures. It is assumed that one of the components, which is rarer and lighter, is present in the mixture in a very small quantity. The equations governing the motion, temperature and concentration in Cartesian coordinate are solved analytically. The solution obtained for concentration distribution is plotted against the width of the channel for various values of non-dimensional parameters. It is found that the effect of transverse magnetic field is to separate the species of rarer and lighter component by contributing its effect directly to the temperature gradient and the pressure gradient. The effects of increase in the values of Hartmann number, magnetic Reynolds number, barodiffusion number, thermal diffusion number, electric field parameter and the product of Prandtl number and Eckert number are to collect the rarer and lighter component near the upper plate and throw away the heavier component towards the lower plate. The problem discussed here derives its application in the basic fluid dynamics separation processes to separate the rare component of the different isotopes of heavier molecules where electromagnetic method of separation does not work.

Sharma Bishwaram; Sing Niroj Ram; Gogoi Rupam KR.; Nath Kabita

2012-01-01

178

Environmental friendly crush-magnetic separation technology for recycling metal-plated plastics from end-of-life vehicles.  

UK PubMed Central (United Kingdom)

Metal-plated plastics (MPP), which are important from the standpoint of aesthetics or even performance, are increasingly employed in a wide variety of situations in the automotive industry. Serious environmental problems will be caused if they are not treated appropriately. Therefore, recycling of MPP is an important subject not only for resource recycling but also for environmental protection. This work represents a novel attempt to deal with the MPP. A self-designed hammer crusher was used to liberate coatings from the plastic substrate. The size distribution of particles was analyzed and described by the Rosin-Rammler function model. The optimum retaining time of materials in the crusher is 3 min. By this time, the liberation rate of the materials can reach 87.3%. When the density of the suspension is 31,250 g/m(3), the performance of liberation is the best. Two-step magnetic separation was adopted to avoid excessive crushing and to guarantee the quality of products. Concerning both the separation efficiency and grade of products, the optimum rotational speed of the magnetic separator is 50-70 rpm. On the basis of the above studies about the liberating and separating behavior of the materials, a continuous recycling system (the technology of crush-magnetic separation) is developed. This recycling system provides a feasible method for recycling MPP efficiently, economically, and environmentally.

Xue M; Li J; Xu Z

2012-03-01

179

Separation of Sudan dyes from chilli powder by magnetic molecularly imprinted polymer.  

Science.gov (United States)

A simple method based on magnetic molecularly imprinted polymers (MMIPs) for the separation of Sudan dyes from chilli powder samples has been developed. The MMIPs were synthesized as follows: the Fe(3)O(4) nanoparticles were encapsulated with a SiO(2) shell and functionalized with -CH=CH(2), then the polymers were further fabricated by surface-imprinted polymerization using Sudan IV as template molecule, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linking agent. The prepared MMIPs were characterized by scanning electron microscope, Fourier transform infrared spectrometry and physical property measurement system. The isothermal absorption experiment, kinetics absorption experiment and selectivity of MMIPs were tested. The analytes were determined by high performance liquid chromatography. Under the optimal conditions, the limits of detection of the four Sudan dyes are 6.2, 1.6, 4.3 and 4.5 ng g(-1), respectively. The precision expressed as relative standard deviation ranging from 4.8% to 9.1% was obtained. In all three fortified levels (25, 250 and 2500 ng g(-1)), recoveries of Sudan dyes were in the range of 79.9-87.8%. PMID:23141623

Piao, Chunying; Chen, Ligang

2012-10-26

180

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

UK PubMed Central (United Kingdom)

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.

Chen A; Byvank T; Chang WJ; Bharde A; Vieira G; Miller BL; Chalmers JJ; Bashir R; Sooryakumar R

2013-03-01

 
 
 
 
181

Separation of Sudan dyes from chilli powder by magnetic molecularly imprinted polymer.  

UK PubMed Central (United Kingdom)

A simple method based on magnetic molecularly imprinted polymers (MMIPs) for the separation of Sudan dyes from chilli powder samples has been developed. The MMIPs were synthesized as follows: the Fe(3)O(4) nanoparticles were encapsulated with a SiO(2) shell and functionalized with -CH=CH(2), then the polymers were further fabricated by surface-imprinted polymerization using Sudan IV as template molecule, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linking agent. The prepared MMIPs were characterized by scanning electron microscope, Fourier transform infrared spectrometry and physical property measurement system. The isothermal absorption experiment, kinetics absorption experiment and selectivity of MMIPs were tested. The analytes were determined by high performance liquid chromatography. Under the optimal conditions, the limits of detection of the four Sudan dyes are 6.2, 1.6, 4.3 and 4.5 ng g(-1), respectively. The precision expressed as relative standard deviation ranging from 4.8% to 9.1% was obtained. In all three fortified levels (25, 250 and 2500 ng g(-1)), recoveries of Sudan dyes were in the range of 79.9-87.8%.

Piao C; Chen L

2012-12-01

182

The magnetic field induced phase separation in a model of a superconductor with local electron pairing.  

UK PubMed Central (United Kingdom)

We have studied the extended Hubbard model with pair hopping in the atomic limit for arbitrary electron density and chemical potential and focus on paramagnetic effects of the external magnetic field. The Hamiltonian considered consists of (i) the effective on-site interaction U and (ii) the intersite charge exchange interactions I, determining the hopping of electron pairs between nearest-neighbour sites. The phase diagrams and thermodynamic properties of this model have been determined within the variational approach (VA), which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. Our investigation of the general case shows that the system can exhibit not only the homogeneous phases-superconducting (SS) and non-ordered (NO)-but also the phase separated states (PS: SS-NO). Depending on the values of interaction parameters, the PS state can occur in higher fields than the SS phase (field induced PS). Some ground state results beyond the VA are also presented.

Kapcia K; Robaszkiewicz S

2013-02-01

183

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

Energy Technology Data Exchange (ETDEWEB)

'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

184

Separation of radioimmunoassay in magnetic phase with particles prepared at the IPEN and its comparison with conventional methodologies  

International Nuclear Information System (INIS)

In the present work two main objectives were chosen. The first was the preparation for the execution of the magnetic phase separation technique, useful for the radioimmunoassay as well as for the most modern and most efficient immunoradiometric assay. The second objective, of a theoretical-practical kind and directly linked to the first, was the realization of a study about the precision of the technique with synthesized products compared with imported products and with two liquid phase separation techniques: the second antibody and polyethyleneglycol (PEG). This analysis was performed with the help of precision profiles built according to R.P.Ekins' recommendations. (author).

1991-01-01

185

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

UK PubMed Central (United Kingdom)

The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with non-magnetic N-doped TiO2 for the removal of cyanotoxin microcystin-LR from aqueous medium. The observed enhanced photocatalytic activity may be related to the presence of ferrite nanoparticles in the composition of the magnetically separable composite N-doped TiO2.

Pelaez M; Baruwati B; Varma RS; Luque R; Dionysiou DD

2013-09-01

186

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

UK PubMed Central (United Kingdom)

The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with non-magnetic N-doped TiO2 for the removal of cyanotoxin microcystin-LR from aqueous medium. The observed enhanced photocatalytic activity may be related to the presence of ferrite nanoparticles in the composition of the magnetically separable composite N-doped TiO2.

Pelaez M; Baruwati B; Varma RS; Luque R; Dionysiou DD

2013-10-01

187

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

Science.gov (United States)

The performance of magnetically separable N-doped TiO2 was found to be significantly improved when compared with non-magnetic N-doped TiO2 for the removal of cyanotoxin microcystin-LR from aqueous medium. The observed enhanced photocatalytic activity may be related to the presence of ferrite nanoparticles in the composition of the magnetically separable composite N-doped TiO2. PMID:24045651

Pelaez, Miguel; Baruwati, Babita; Varma, Rajender S; Luque, Rafael; Dionysiou, Dionysios D

2013-10-01

188

Decreasing of ash and sulfur contents of Istanbul-Yenikoy region of semicoked lignite by high intensity dry magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

In this study, two procedures were applied to Istanbul-Yenikoy region lignites. At first, in order to decrease sulphur content of the coal, pyrite has been magnetised by heat treatment. Secondly, eliminating the ash and sulphur content of the coal by the high intensity dry magnetic separator (Permroll) tests were achieved. In the tests done by methods of magnetic separation following heat treatment of 120 minutes at 600{degree}C for the coal at -9 mm, reductions by 89% and 57% in total sulphur and ash has been achieved respectively. It is determined that in the calorific value of the coal was increased 6347 kcal/kg by 40%. 5 refs., 9 figs., 6 tabs.

Atesok, G.; Perek, K.T.; Unal, L.B. [ITU Maden Fak., Istanbul (Turkey)

1998-12-31

189

Simple analytical model for the magnetophoretic separation of superparamagnetic dispersions in a uniform magnetic gradient.  

Science.gov (United States)

Magnetophoresis--the motion of magnetic particles under applied magnetic gradient--is a process of great interest in novel applications of magnetic nanoparticles and colloids. In general, there are two main different types of magnetophoresis processes: cooperative magnetophoresis (a fast process enhanced by particle-particle interactions) and noncooperative magnetophoresis (driven by the motion of individual particles in magnetic fields). In the case of noncooperative magnetophoresis, we have obtained a simple analytical solution which allows the prediction of the magnetophoresis kinetics from particle characterization data (size and magnetization). Our comparison with new experimental results shows good quantitative agreement. In addition, we show the existence of a universal curve onto which all experimental results should collapse after proper rescaling. The range of applicability of the analytical solution is discussed in light of the predictions of a magnetic aggregation model [Soft Matter 7, 2336 (2011)]. PMID:21928989

Andreu, J S; Camacho, J; Faraudo, J; Benelmekki, M; Rebollo, C; Martínez, Ll M

2011-08-22

190

Simple analytical model for the magnetophoretic separation of superparamagnetic dispersions in a uniform magnetic gradient.  

UK PubMed Central (United Kingdom)

Magnetophoresis--the motion of magnetic particles under applied magnetic gradient--is a process of great interest in novel applications of magnetic nanoparticles and colloids. In general, there are two main different types of magnetophoresis processes: cooperative magnetophoresis (a fast process enhanced by particle-particle interactions) and noncooperative magnetophoresis (driven by the motion of individual particles in magnetic fields). In the case of noncooperative magnetophoresis, we have obtained a simple analytical solution which allows the prediction of the magnetophoresis kinetics from particle characterization data (size and magnetization). Our comparison with new experimental results shows good quantitative agreement. In addition, we show the existence of a universal curve onto which all experimental results should collapse after proper rescaling. The range of applicability of the analytical solution is discussed in light of the predictions of a magnetic aggregation model [Soft Matter 7, 2336 (2011)].

Andreu JS; Camacho J; Faraudo J; Benelmekki M; Rebollo C; Martínez LM

2011-08-01

191

The Vlasov equation with strong magnetic field and oscillating electric field as a model for isotop resonant separation  

Directory of Open Access Journals (Sweden)

Full Text Available We study the qualitative behavior of solutions to the Vlasov equation with strong external magnetic field and oscillating electric field. This model is relevant to the understanding of isotop resonant separation. We show that the effective equation is a kinetic equation with a memory term. This memory term involves a pseudo-differential operator whose kernel is characterized by an integral equation involving Bessel functions. The kernel is explicitly given in some particular cases.

Emmanuel Frenod; Frederique Watbled

2002-01-01

192

Polyvinyl-alcohol-based magnetic beads for rapid and efficient separation of specific or unspecific nucleic acid sequences  

International Nuclear Information System (INIS)

[en] The versatile application of polyvinyl-alcohol-based magnetic M-PVA beads is demonstrated in the separation of genomic DNA, sequence specific nucleic acid purification, and binding of bacteria for subsequent DNA extraction and detection. It is shown that nucleic acids can be obtained in high yield and purity using M-PVA beads, making sample preparation efficient, fast and highly adaptable for automation processes

2001-01-01

193

Polyvinyl-alcohol-based magnetic beads for rapid and efficient separation of specific or unspecific nucleic acid sequences  

Energy Technology Data Exchange (ETDEWEB)

The versatile application of polyvinyl-alcohol-based magnetic M-PVA beads is demonstrated in the separation of genomic DNA, sequence specific nucleic acid purification, and binding of bacteria for subsequent DNA extraction and detection. It is shown that nucleic acids can be obtained in high yield and purity using M-PVA beads, making sample preparation efficient, fast and highly adaptable for automation processes.

Oster, J. E-mail: juergen.oster@chemagen.de; Parker, Jeffrey; Brassard, Lothar

2001-07-01

194

Potential application of antibody-mimicking peptides identified by phage display in immuno-magnetic separation of an antigen.  

UK PubMed Central (United Kingdom)

Phage display was performed against human IgG (hIgG) through five rounds of 'biopanning'. Each round consisted of: (1) incubating a library of phage-displayed 12-mer peptides sequences on hIgG-coated magnetic beads, (2) washing the unbound phages, and (3) eluting the bound phages. The eluted phages were either amplified to enrich the pool of positive clones or subjected to the next round without amplification. Through ELISA, four clones (F9, D1, G5, and A10) showing specific binding affinity to hIgG were identified. Among these, F9 had the highest affinity (K(d)=6.2 nM), only one order of magnitude lower than the native anti-hIgG antibody (0.66 nM). Following the DNA sequences of the selected clones, four 12-mer peptides were chemically synthesized. Among them, D1 peptide showed the highest binding affinity to hIgG via SPR biosensor measurements. This peptide was conjugated to biofunctionalized magnetic beads, and its immuno-binding ability was compared with that of the native antibody immobilized to magnetic beads. The mol-to-mol binding efficacy of the peptide-coated magnetic beads was approximately 1000-fold lower than that of the antibody-coated magnetic beads. Our results suggest a feasibility of using antibody-mimicking peptides identified by phage display technique for immuno-magnetic separation of an antigen.

Hien TB; Maeng JH; Lee BH; Seong GH; Choo J; Lee EK

2012-10-01

195

A new concept of isotope separation using ion cyclotron resonance in a magnetic field having a radial component  

International Nuclear Information System (INIS)

A new method of isotope separation is proposed. Isotopes are ionized in a magnetic field in a solenoid and are confined axially in an electrostatic potential well. Ions moving in a cyclotron orbit undergo a force which is perpendicular to both the radial magnetic field component and the velocity. Because axial oscillation takes place over the region where the component changes its direction, two isotopes can be separated in opposite directions by accelerating one of the isotopes at one extreme of the oscillation and the other at the other extreme. The axial motion of ions is assumed to be in phase (phase-locked). To experimentally confirm the effect of the radial components on ion motion, we moved the center of oscillation along the axis of the solenoid from its center to a position where both the axial and radial components vary with the coordinates, and we excited the cyclotron motion of ions. From the measured shift in the signal frequency of the accelerated ions, we could estimate the amount of displacement of the center of the cyclotron orbit as a function of the velocity of the accelerated ions. The condition for separation is studied by solving the equation for ion motion with two different magnetic field distributions. Computer simulation of the ion trajectory is carried out to demonstrate the feasibility of the method. (author)

1993-01-01

196

Correlation between electrical and magnetic properties of phase-separated manganites studied with a general effective medium model  

International Nuclear Information System (INIS)

We have performed electrical resistivity and DC magnetization measurements as a function of temperature, on polycrystalline samples of phase-separated La5/8- y Pr y Ca3/8MnO3 (y=0.3). We have used the general effective medium theory to obtain theoretical resistivity vs. temperature curves corresponding to different fixed ferromagnetic (FM) volume fraction values, assuming that the sample is a mixture of typical metallic-like and insulating manganites. By comparing this data with our experimental resistivity curves we have obtained the relative FM volume fraction of our sample as a function of temperature. This result matches with the corresponding magnetization data in excellent agreement, showing that a mixed-phase scenario is the key element to explain both the magnetic and transport properties in the present compound.

1499-01-00

197

Synthesis and performance of novel magnetically separable nanospheres of titanium dioxide photocatalyst with egg-like structure  

Energy Technology Data Exchange (ETDEWEB)

A magnetically separable photocatalyst TiO{sub 2}/SiO{sub 2}/NiFe{sub 2}O{sub 4} (TSN) nanosphere with egg-like structure was prepared by a unique process that combined a liquid catalytic phase transformation method, reverse micelle technique and chemical precipitation means. The prepared photocatalyst shows high photocatalytic activity for the degradation of methyl orange in water. The magnetic property measurements indicate that the photocatalyst possesses a superparamagnetic nature. It can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for wastewater treatment. A transmission electron microscope (TEM) and an x-ray diffractometer (XRD) were used to characterize the structure of the TSN photocatalyst. The results indicate that nickel ferrite core nanoparticles were completely encapsulated into monodisperse silica nanospheres as carrier, and titania nanoparticle aggregates were coated onto the surface of SN nanospheres, forming an imperfect TiO{sub 2} shell for photocatalysis. The SiO{sub 2} layer between the NiFe{sub 2}O{sub 4} core and the TiO{sub 2} shell effectively prevents the injection of charges from TiO{sub 2} particles to NiFe{sub 2}O{sub 4}, which gives rise to an increase in photocatalytic activity. Moreover, the recycled TSN exhibits good repeatability of the photocatalytic activity.

Xu Shihong; Shangguan Wenfeng; Yuan Jian; Chen Mingxia; Shi Jianwei; Jiang Zhi [Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University, Shanghai 200240 (China)], E-mail: shangguan@sjtu.edu.cn

2008-03-05

198

Synthesis and performance of novel magnetically separable nanospheres of titanium dioxide photocatalyst with egg-like structure  

International Nuclear Information System (INIS)

A magnetically separable photocatalyst TiO2/SiO2/NiFe2O4 (TSN) nanosphere with egg-like structure was prepared by a unique process that combined a liquid catalytic phase transformation method, reverse micelle technique and chemical precipitation means. The prepared photocatalyst shows high photocatalytic activity for the degradation of methyl orange in water. The magnetic property measurements indicate that the photocatalyst possesses a superparamagnetic nature. It can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for wastewater treatment. A transmission electron microscope (TEM) and an x-ray diffractometer (XRD) were used to characterize the structure of the TSN photocatalyst. The results indicate that nickel ferrite core nanoparticles were completely encapsulated into monodisperse silica nanospheres as carrier, and titania nanoparticle aggregates were coated onto the surface of SN nanospheres, forming an imperfect TiO2 shell for photocatalysis. The SiO2 layer between the NiFe2O4 core and the TiO2 shell effectively prevents the injection of charges from TiO2 particles to NiFe2O4, which gives rise to an increase in photocatalytic activity. Moreover, the recycled TSN exhibits good repeatability of the photocatalytic activity.

2008-03-05

199

The effect of particle size and colloid stability on the wet high-intensity magnetic separation of uranium from cyanidation residues  

International Nuclear Information System (INIS)

This report describes an experimental investigation on the magnetic separation of U3O8 from various size fractions of uranium-gold tailings. High recoveries were obtained at high grades, even from the finest fraction (smaller than 25?m), and an increase in magnetic field did not improve the efficiency of separation. The use of theoretical models did not lead to the correct prediction of the limiting particle size recoverable by magnetic separation. It was shown that the presence of coarse fractions enhances the recovery of uranium from a very fine fraction, and that 'piggy-back' magnetic separation plays an important role in the capture of slimes. The results also showed that the use of a dispersant considerably improves the selectivity of the separation.

1986-01-01

200

Possible Magnetic separation in Ru doped La0.67Ca0.33MnO3  

CERN Document Server

X-ray diffraction, resistivity, ac susceptibility and magnetization studies on La0.67Ca0.33Mn1-xRuxO3 (0 x < 0.1) were carried out. A significant increase in the lattice parameters indicated the presence of mixed valance state of Ru: Ru3+ and Ru4+. The resistivity of the doped compounds exhibited two features: a broad maximum and a relatively sharp peak. While a para to ferromagnetic transition could be observed for the latter peak, no magnetic signal either in ac susceptibility or in magnetization measurements could be observed for the broad maximum. The magnetic moment decreases non linearly from 3.55 to 3 mB over the Ru composition from 0 to 8.5 at.%. Based on the results of the present studies and on existing literature on the Mn-site substituted systems, we argue that a magnetic phase separation occurs in the Ru doped system. While the sharp peak in the resistivity corresponds to Ru4+ enriched region with a ferromagnetic coupling with neighboring Mn ions, the broad peak corresponds to a Ru3+ rich regi...

Lakshmi, L S; Natarajan, D V; Chandra, S; Sastry, V S; Radhakrishnan, T S; Pandian, P; Narayana-Swamy, A; Chandra, Sharat; Pandian, Ponn

2002-01-01

 
 
 
 
201

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

Science.gov (United States)

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

2013-09-30

202

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

UK PubMed Central (United Kingdom)

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.

Wang J; Morabito K; Erkers T; Tripathi A

2013-09-01

203

Separating inner and outer Earth's magnetic field from CHAMP satellite measurements by means of vector scaling functions and wavelets  

Science.gov (United States)

This article is concerned with an approach of modelling the Earth's magnetic field, as measured by satellites, in terms of vector kernel functions, which we will call vector scaling functions and wavelets. The major ingredient is the presentation of a system of vector spherical harmonics which separates a given spherical vector field with respect to its sources, that is, the spherical vector field is separated into a part which is generated by sources inside the sphere, a part which is generated by sources outside the sphere and a part which is generated by sources on the sphere, which are, for example, currents crossing the sphere. Using this special system of vector spherical harmonics vector scaling functions and wavelets are constructed which keep the advantageous property of separating with respect to source but which also allow a locally adapted modelling of the respective vector field. At the end of the article, the method is tested on magnetic field data measured by the German geoscientific research satellite CHAMP.

Mayer, C.; Maier, T.

2006-12-01

204

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

Energy Technology Data Exchange (ETDEWEB)

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

205

A Magnetically Separable, Highly Stable Enzyme System Based on Nanocomposites of Enzymes and Magnetic Nanoparticles Shipped in Hierarchically Ordered, Mesocellular, Mesoporous Silica  

Energy Technology Data Exchange (ETDEWEB)

Enzymes are versatile nanoscale biocatalysts, and find increasing applications in many areas, including organic synthesis[1-3] and bioremediation.[4-5] However, the application of enzymes is often hampered by the short catalytic lifetime of enzymes and by the difficulty in recovery and recycling. To solve these problems, there have been a lot of efforts to develop effective enzyme immobilization techniques. Recent advances in nanotechnology provide more diverse materials and approaches for enzyme immobilization. For example, mesoporous materials offer potential advantages as a host of enzymes due to their well-controlled porosity and large surface area for the immobilization of enzymes.[6,7] On the other hand, it has been demonstrated that enzymes attached on magnetic iron oxide nanoparticles can be easily recovered using a magnet and recycled for iterative uses.[8] In this paper, we report the development of magnetically-separable and highly-stable enzyme system by the combined use of two different kinds of nanostructured materials: magnetic nanoparticles and mesoporous silica.

Kim, Jungbae; Lee, Jinwoo; Na, Hyon Bin; Kim, Byoung Chan; Youn, Jongkyu; Kwak, Ja Hun; Moon, Karam; Lee, Eunwoong; Kim, Jaeyun; Park, Jongnam; Dohnalkova, Alice; Park, Hyun-Gyu; Gu, Man Bock; Chang, Ho Nam; Grate, Jay W.; Hyeon, Taeghwan

2005-12-01

206

In-beam spectroscopy using the JYFL gas-filled magnetic recoil separator RITU  

International Nuclear Information System (INIS)

The techniques of recoil-gating and recoil-decay tagging have been employed at Jyvaeskylae to perform in-beam ?-ray and electron spectroscopy studies of heavy nuclei. The JUROSPHERE ?-ray array and the SACRED electron spectrometer have been placed at the target position of the JYFL gas-filled recoil separator recoil ion transport unit (RITU). The RITU separator has been used to collect the recoils of interest and separate them from beam particles and fission products. At the focal plane a detector system consisting of time-of-flight and implantation detectors has been used for further event identification. The method and some highlights from the results in the lead region close to the proton drip line and in the transuranium region will be presented and discussed.

2003-01-01

207

In-beam spectroscopy using the JYFL gas-filled magnetic recoil separator RITU  

CERN Multimedia

The techniques of recoil-gating and recoil-decay tagging have been employed at Jyvaeskylae to perform in-beam gamma-ray and electron spectroscopy studies of heavy nuclei. The JUROSPHERE gamma-ray array and the SACRED electron spectrometer have been placed at the target position of the JYFL gas-filled recoil separator recoil ion transport unit (RITU). The RITU separator has been used to collect the recoils of interest and separate them from beam particles and fission products. At the focal plane a detector system consisting of time-of-flight and implantation detectors has been used for further event identification. The method and some highlights from the results in the lead region close to the proton drip line and in the transuranium region will be presented and discussed.

Uusitalo, J; Greenlees, P T; Rahkila, P; Leino, M; Andreyev, A N; Butler, P A; Enqvist, T; Eskola, Kari J; Grahn, T; Herzberg, R D; Hessberger, F P; Julin, R; Juutinen, S; Keenan, A; Kettunen, H; Kuusiniemi, P; Leppaenen, A P; Nieminen, P; Page, R; Pakarinen, J; Scholey, C

2003-01-01

208

In-beam spectroscopy using the JYFL gas-filled magnetic recoil separator RITU  

Energy Technology Data Exchange (ETDEWEB)

The techniques of recoil-gating and recoil-decay tagging have been employed at Jyvaeskylae to perform in-beam {gamma}-ray and electron spectroscopy studies of heavy nuclei. The JUROSPHERE {gamma}-ray array and the SACRED electron spectrometer have been placed at the target position of the JYFL gas-filled recoil separator recoil ion transport unit (RITU). The RITU separator has been used to collect the recoils of interest and separate them from beam particles and fission products. At the focal plane a detector system consisting of time-of-flight and implantation detectors has been used for further event identification. The method and some highlights from the results in the lead region close to the proton drip line and in the transuranium region will be presented and discussed.

Uusitalo, J. E-mail: juha.uusitalo@phys.jyu.fihttp://www.phys.jyu.fi; Jones, P.; Greenlees, P.; Rahkila, P.; Leino, M.; Andreyev, A.N.; Butler, P.A.; Enqvist, T.; Eskola, K.; Grahn, T.; Herzberg, R.-D.; Hessberger, F.; Julin, R.; Juutinen, S.; Keenan, A.; Kettunen, H.; Kuusiniemi, P.; Leppaenen, A-P.; Nieminen, P.; Page, R.; Pakarinen, J.; Scholey, C

2003-05-01

209

Magnetic and highly recyclable macroporous carbon nanotubes for spilled oil sorption and separation.  

UK PubMed Central (United Kingdom)

Development of sorbent materials with high selectivity and sorption capacity, easy collection and recyclability is demanding for spilled oil recovery. Although many sorption materials have been proposed, a systematic study on how they can be reused and possible performance degradation during regeneration remains absent. Here we report magnetic carbon nanotube sponges (Me-CNT sponge), which are porous structures consisting of interconnected CNTs with rich Fe encapsulation. The Me-CNT sponges show high mass sorption capacity for diesel oil reached 56 g/g, corresponding to a volume sorption capacity of 99%. The sponges are mechanically strong and oil can be squeezed out by compression. They can be recycled using through reclamation by magnetic force and desorption by simple heat treatment. The Me-CNT sponges maintain original structure, high capacity, and selectivity after 1000 sorption and reclamation cycles. Our results suggest that practical application of CNT macrostructures in the field of spilled oil recovery is feasible.

Gui X; Zeng Z; Lin Z; Gan Q; Xiang R; Zhu Y; Cao A; Tang Z

2013-06-01

210

Synthetic Ligand-Coated Magnetic Nanoparticles for Microfluidic Bacterial Separation from Blood.  

UK PubMed Central (United Kingdom)

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.

Lee JJ; Jeong KJ; Hashimoto M; Kwon AH; Rwei A; Shankarappa SA; Tsui JH; Kohane DS

2013-01-01

211

PDMAEMA-Grafted Core-Shell-Corona Particles for Nonviral Gene Delivery and Magnetic Cell Separation.  

Science.gov (United States)

Monodisperse, magnetic nanoparticles as vectors for gene delivery were successfully synthesized via the grafting-from approach. First, oleic acid stabilized maghemite nanoparticles (?-Fe2O3) were encapsulated with silica utilizing a reverse microemulsion process with simultaneous functionalization with initiating sites for atom transfer radical polymerization (ATRP). Polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) from the core-shell nanoparticles led to core-shell-corona hybrid nanoparticles (?-Fe2O3@silica@PDMAEMA) with an average grafting density of 91 polymer chains of DPn = 540 (PDMAEMA540) per particle. The permanent attachment of the arms was verified by field-flow fractionation. The dual-responsive behavior (pH and temperature) was confirmed by dynamic light scattering (DLS) and turbidity measurements. The interaction of the hybrid nanoparticles with plasmid DNA at various N/P ratios (polymer nitrogen/DNA phosphorus) was investigated by DLS and zeta-potential measurements, indicating that for N/P ? 7.5 the complexes bear a positive net charge and do not undergo secondary aggregation. The hybrids were tested as transfection agents under standard conditions in CHO-K1 and L929 cells, revealing transfection efficiencies >50% and low cytotoxicity at N/P ratios of 10 and 15, respectively. Due to the magnetic properties of the hybrid gene vector, it is possible to collect most of the cells that have incorporated a sufficient amount of magnetic material by using a magnetic activated cell sorting system (MACS). Afterward, cells were further cultivated and displayed a transfection efficiency of ca. 60% together with a high viability. PMID:23889326

Majewski, Alexander P; Stahlschmidt, Ullrich; Jérôme, Valérie; Freitag, Ruth; Müller, Axel H E; Schmalz, Holger

2013-08-12

212

PDMAEMA-Grafted Core-Shell-Corona Particles for Nonviral Gene Delivery and Magnetic Cell Separation.  

UK PubMed Central (United Kingdom)

Monodisperse, magnetic nanoparticles as vectors for gene delivery were successfully synthesized via the grafting-from approach. First, oleic acid stabilized maghemite nanoparticles (?-Fe2O3) were encapsulated with silica utilizing a reverse microemulsion process with simultaneous functionalization with initiating sites for atom transfer radical polymerization (ATRP). Polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) from the core-shell nanoparticles led to core-shell-corona hybrid nanoparticles (?-Fe2O3@silica@PDMAEMA) with an average grafting density of 91 polymer chains of DPn = 540 (PDMAEMA540) per particle. The permanent attachment of the arms was verified by field-flow fractionation. The dual-responsive behavior (pH and temperature) was confirmed by dynamic light scattering (DLS) and turbidity measurements. The interaction of the hybrid nanoparticles with plasmid DNA at various N/P ratios (polymer nitrogen/DNA phosphorus) was investigated by DLS and zeta-potential measurements, indicating that for N/P ? 7.5 the complexes bear a positive net charge and do not undergo secondary aggregation. The hybrids were tested as transfection agents under standard conditions in CHO-K1 and L929 cells, revealing transfection efficiencies >50% and low cytotoxicity at N/P ratios of 10 and 15, respectively. Due to the magnetic properties of the hybrid gene vector, it is possible to collect most of the cells that have incorporated a sufficient amount of magnetic material by using a magnetic activated cell sorting system (MACS). Afterward, cells were further cultivated and displayed a transfection efficiency of ca. 60% together with a high viability.

Majewski AP; Stahlschmidt U; Jérôme V; Freitag R; Müller AH; Schmalz H

2013-09-01

213

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

Science.gov (United States)

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

2012-02-22

214

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

UK PubMed Central (United Kingdom)

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.

Majewski AP; Schallon A; Jérôme V; Freitag R; Müller AH; Schmalz H

2012-03-01

215

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

Science.gov (United States)

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

2013-04-02

216

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

UK PubMed Central (United Kingdom)

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.

Samouhos M; Taxiarchou M; Tsakiridis PE; Potiriadis K

2013-06-01

217

Polarization separated Zeeman spectra from magnetic dipole transitions in highly charged argon in the large helical device  

International Nuclear Information System (INIS)

Visible spectral emission lines from magnetic dipole transitions in Ar X, Ar XI, Ar XIV, and Ar XV are observed from plasmas heated with neutral-beam injection (NBI) in the Large Helical Device [O. Motojima et al., Phys. Plasmas 6, 1843 (1999)]. Orthogonal linearly polarized components of the emission line profiles are observed with a polarization separation optical system and high-resolution spectrometer. Zeeman split profiles reveal polarization characteristics of magnetic dipole transitions. Ion temperatures and emission locations are estimated from the profiles with the magnetic field information on the lines of sight (LOS). The spatially resolved emissions are observed by the array of absolutely calibrated views. The time histories of line profiles and emission intensities at the poloidal view are presented. The observed line profiles and the intensity distribution at the poloidal view indicate the localization of these charge states in the edge region just inside the last closed flux surface. The emission line of Ar X in the tangential observation indicates Doppler shifts of the Zeeman split profiles. The velocity components of Ar X ion flow along the LOS at the tangential view are 7.7 and 2.0 km/s at the outer and inner edge plasmas, respectively, in the opposite direction to the NBI

2007-01-01

218

Process for decontaminating radioactive waste water using a ferrofluid and magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides a process for decontaminating radioactive waste water containing a radioactive element that forms a water-insoluble compound. This process includes the steps of forming the compound of the radioactive element, treating the resulting waste water with a ferrofluid, dispersing the ferrofluid, diluting the solids concentration of the resulting mixture with a coagulation initiator, such as ethyl alcohol or acetone, and collecting by use of a magnetic field, the resulting radioactive sludge. In a variation of the process, the steps involving the use of the coagulation initiator and the use of the ferrofluid are reversed.

Silver, G.L.

1980-07-31

219

Computer simulation of magnetic chromatography system for ultra-fine particle separation; Jiki chromatography ni okeru biryushi bunri no keisanki simulation  

Energy Technology Data Exchange (ETDEWEB)

We propose magnetic chromatography (MC) as a new technique for ultra-fine particle separation. We developed an MC simulator, and modeled the transient behavior of 300 angstrom and 500 angstrom particles by taking into account the fluid flow field, magnetic field distribution, and particle diffusion. For the range of flow velocity between 1.0 times 10{sup -4} and 1.0 times 10{sup -3} m/s, the separation efficiency increased with decreasing the flow velocity and increasing the ratio of particle magnetic susceptibility. To improve the separation efficiency, it is also very important to extend the channel length; longer channels (4.0m) completely separated two kinds of ultra-fine particles that can not be separated by shorter channels (I.e., 0.4m). For the smaller particles (300 angstrom), increasing the applied magnetic field strength improves the separation efficiency. We also simulated other types of MC systems, and found that regardless of flow velocity an MC system with a staggered-wire arrangement always has better separation efficiency than an MC system with a face-to-face wire arrangement. 7 refs., 12 figs., 7 tabs.

Wang, X. [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)] Ohara, K. [Electrotechnical Lab., Ibaraki (Japan); Karki, K.; Winstead, C.

1997-10-20

220

Phase-separated alloys for bulk exchange-biased permanent magnets  

Science.gov (United States)

Explorations in the metallurgical synthesis from the melt of bulk permanent magnets with coercivity conferred by the exchange bias mechanism were carried out in a two-phase materials system composed of ferromagnetic FeCo and antiferromagnetic, nominally equiatomic AuMn. Rapid solidification synthesis of composite alloys of nominal composition (Fe65Co35)100-x(AuMn)x (x=5, 10, and 15) was carried out. The ribbons possess AuMn and Au2Mn spherical phases in a bcc (Fe,Co) matrix with a bimodal size distribution of nanoscaled and micron sizes. Magnetization measurements of the composite confirm an exchange bias effect correlated with a coercivity increase over that of the (Fe,Co) melt-spun base alloy. While the exchange bias effect is small, the enhanced coercivity and shifted hysteresis loop observed in a single sample create a strong argument for coercivity enhancement conferred by the exchange bias interaction between antiferromagnetic and ferromagnetic phases in a bulk melt-spun nanocomposite material.

Lewis, L. H.; Harland, C. L.; McCallum, R. W.; Kramer, M. J.; Dennis, K. W.

2006-04-01

 
 
 
 
221

Systematic comparisons of genetically modified organism DNA separation and purification by various functional magnetic nanoparticles  

UK PubMed Central (United Kingdom)

DNA extraction is always an important and key step in bioanalytical fields for target nucleic acid detection. Traditional organic solvent?based extraction methods are toxic and time?consuming. In this work, we report a systematic study of magnetic nanoparticles (MNPs) as probes for genomic DNA extraction from genetically modified organism (GMO) plants. Different surface?functionalised MNPs with controllable diameters have been used to extract the genomic DNA directly from GMO plants for detections. Systematic comparison of the results obtained under different extraction conditions has indicated that carboxyl?modified MNPs with smaller diameters are more suitable for genomic DNA extractions. The successful qualitative detection of GMO and non?GMO products based on the MNP extracted DNA is also achieved and discussed in this article. In view of the advantages of magnetic extraction, such as nontoxicity, ease of operation, and rapid and high throughput, this systematic research has demonstrated the great potential of the method and provides theoretical guidance for practical MNP applications.

Zhao Y; Hao C; Yong Q; Qu C; Chen W; Peng C; Kuang H; Zhou H; Wang L; Xu C

2012-05-01

222

Versatile fabrication of ultralight magnetic foams and application for oil-water separation.  

UK PubMed Central (United Kingdom)

Ultralow-density (<10 mg cm(-3)) materials have many important technological applications; however, most of them were fabricated using either expensive materials or complicated procedures. In this study, ultralight magnetic Fe2O3/C, Co/C, and Ni/C foams (with a density <5 mg cm(-3)) were fabricated on the centimeter scale by pyrolyzing commercial polyurethane sponge grafted with polyelectrolyte layers based on the corresponding metal acrylate at 400 °C. The ultralight foams consisted of 3D interconnected hollow tubes that have a diameter of micrometer and nanoscale wall thickness, forming hierarchical structures from macroscopic to nanometer length scales. More interesting was that the wall thickness and morphology of the microtubes could be tuned by controlling the concentrations of acrylic acid and metallic cations. After modification with low-surface-energy polysiloxane, the ultralight foams showed superhydrophobicity and superoleophilicity, which quickly and selectively absorbed a variety of oils from a polluted water surface under magnetic field. The oil absorption capacity reached 100 times of the foams' own weight, exhibiting one of the highest values among existing absorptive counterparts. By controlling the composition and conformation of the grafted polyelectrolyte layers, the present approach is extendable to fabricate a variety of ultralow-density materials desirable for absorptive materials, electrode materials, catalyst supports, etc.

Chen N; Pan Q

2013-08-01

223

Magnetic resonance method which automatically forms water/fat separated images with different echo times and determines that proper phase unwrapping has been utilized  

UK PubMed Central (United Kingdom)

A magnetic resonance imaging method for fully automatically forming a water/fat separated image by calculation after acquiring data on images of different echo times, wherein the unwrapping of a phase map showing the distribution of the phase rotation due to the inhomogeneous static magnetic field is repeated so as to determine the distribution of the inhomogeneous static magnetic field by using an index used for judging whether or not the unwrapping is properly being performed, and wherein during the formation of a water/fat separated image with correction of the static magnetic field, the unwrapping is automatically and properly performed in correcting the static magnetic field, and the water/fat images are automatically discriminated.

YATSUI YUMIKO; TAKAHASHI TETSUHIKO

224

Facile synthesis of porous Fe7Co3/carbon nanocomposites and their applications as magnetically separable adsorber and catalyst support.  

UK PubMed Central (United Kingdom)

A facile co-gelation route has been developed to synthesize novel porous Fe(7)Co(3)/carbon composites with Fe(7)Co(3) nanoparticles embedded in the porous carbon matrix. The sol-gel process of this route simultaneously involves the hydrolysis of tetraethylorthosilicate (TEOS) and the polymerization of furfuryl alcohol (FA) within an ethanol solution containing TEOS, FA, and metal nitrates, which led to the inorganic/organic hybrid xerogel, accompanying metal salts spontaneously captured in the xerogel, mostly in the framework of poly(furfuryl alcohol) (PFA). Compared to the nanocasting route, the advantage of this method is that the formation of silica template and the impregnation of carbon precursor and metal salts were simultaneously carried out in one co-gelation process, which makes the synthesis very simple and eliminates the time-consuming synthesis of the silica template and multistep impregnation process. Different amounts of Fe(7)Co(3) can be introduced into the composites, which led to different pore structures and magnetic properties. The composites have large surface areas (as high as 651.4 m(2)/g) and high saturation magnetizations (as high as 31.2 emu/g). The Fe(7)Co(3)/carbon composites prepared were successfully applied to the removal of dyes from water and catalysis of hydrogenation as efficient magnetically separable adsober and catalyst support. The facile co-gelation route makes the scalable synthesis of magnetic porous carbon possible for application, and it also provides a promising path to the synthesis of nanoscale metal or alloy embedded in the porous carbon materials.

Wang Z; Liu R; Zhao F; Liu X; Lv M; Meng J

2010-06-01

225

Cryo magnetic separation adaptation to environment technologies: application to industrial effluents; Adaptation de la separation cryomagnetique aux technologies de l`environnement: application a l`epuration d`effluents liquides industriels  

Energy Technology Data Exchange (ETDEWEB)

Cryomagnetic separation adaptation to environment technologies application to industrial liquid effluents. The performance, obtained by superconducting high filed - high gradient magnetic separation, permitted to foresee the magnetic treatment of heavy metals in rinse waters, derived from the surface finishing industry. The paramagnetic ions, precipitated in basic media as hydroxides, present a very hydrated amorphous structure, which masks their subjacent magnetic properties. Coprecipitation of a `magnetic carrier`, jointly with the heavy metals, has been studied: ferric chloride forms in basic media, an hydrated iron oxide. Its structure is of the goethite type, and it stabilizes as hematite. The magnetic susceptibility of the obtained product is still weak and its crystalline structure is not enough affirmative to utilize magnetic filtration with efficiency. Mixture of ferrous sulphate and ferric chloride forms, in a basic media, an hydrated magnetite. Initial ideal ratio between divalent iron and trivalent iron, varies between 0,5 and 1,2. This mixture, coprecipitated with the heavy metals, permits to optimize the magnetic cleaning of the fluids in a high field - high gradient filter. (author)

Bureau, V.

1993-12-20

226

A magnetically separable biocatalyst for resolution of racemic naproxen methyl ester.  

Science.gov (United States)

Candida rugosa lipase (CRL) was encapsulated via the sol-gel method, using 5, 11, 17, 23-tetra-tert-butyl-25,27-bis(2-aminopyridine)carbonylmethoxy-26, 28-dihydroxy-calix[4]arene-grafted magnetic Fe3O4 nanoparticles (Calix-M-E). The catalytic activity of encapsulated lipase (Calix-M-E) was tested both in the hydrolysis of p-nitrophenyl palmitate (p-NPP) and the enantioselective hydrolysis of racemic naproxen methyl ester. The present study demonstrated that the calixarene-based compound has the potential to enhance both reaction rate and enantioselectivity of the lipase-catalyzed hydrolysis of racemic naproxen methyl ester. The encapsulated lipase (Calix-M-E) had great catalytic activity and enantioselectivity (E > 400), as well as remarkable reusability as compared to the encapsulated lipase without supports (E = 137) for S-Naproxen. PMID:23525833

Ozyilmaz, Elif; Sayin, Serkan

2013-03-23

227

A magnetically separable biocatalyst for resolution of racemic naproxen methyl ester.  

UK PubMed Central (United Kingdom)

Candida rugosa lipase (CRL) was encapsulated via the sol-gel method, using 5, 11, 17, 23-tetra-tert-butyl-25,27-bis(2-aminopyridine)carbonylmethoxy-26, 28-dihydroxy-calix[4]arene-grafted magnetic Fe3O4 nanoparticles (Calix-M-E). The catalytic activity of encapsulated lipase (Calix-M-E) was tested both in the hydrolysis of p-nitrophenyl palmitate (p-NPP) and the enantioselective hydrolysis of racemic naproxen methyl ester. The present study demonstrated that the calixarene-based compound has the potential to enhance both reaction rate and enantioselectivity of the lipase-catalyzed hydrolysis of racemic naproxen methyl ester. The encapsulated lipase (Calix-M-E) had great catalytic activity and enantioselectivity (E > 400), as well as remarkable reusability as compared to the encapsulated lipase without supports (E = 137) for S-Naproxen.

Ozyilmaz E; Sayin S

2013-03-01

228

LS separation of J=1/2 Mott insulator observed by magnetic X-ray diffraction  

Science.gov (United States)

Spin-orbit coupling is a key concept to realize spin Hall effect in insulating materials. A perovskite iridate Sr2IrO4 is known to show insulating transport properties in spite of large spatial extent of 5d electrons. The origin of this unconventional behavior is argued to be a strong LS coupling which results in Jeff=1/2 Mott insulator. We performed off-resonant magnetic X-ray scattering in the antiferromagnetically ordered state of this material and found that considerable contribution from orbital moment for the ordered moment. The estimated ratio, / is 5. This is consistent with Jeff=1/2 which expects the ratio as 4. This justifies unconventional Jeff=1/2 Mott insulator for this transition metal oxides.

Fujiyama, Shigeki; Kim, B. J.; Ohsumi, H.; Komesu, T.; Hirai, D.; Ohashi, K.; Sakai, S.; Arima, T.; Takagi, H.

2009-03-01

229

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

Science.gov (United States)

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.

2013-01-01

230

Possible phase separation in the underdoped La2-xSrxCuO4 studied by the magnetic susceptibility  

International Nuclear Information System (INIS)

In order to investigate the inhomogeneity of the superconductivity, we have grown a large-sized single-crystal of La2-xSrxCuO4 (LSCO), in which the Sr concentration, x, continuously changes in the underdoped regime, and measured the magnetic susceptibility on field cooling for several pieces of single crystal with different x values by slicing the single crystal. It has been found that the Meissner volume fraction, regarded as corresponding to the superconducting (SC) volume fraction in a sample, increases with increasing x. This suggests that a phase separation into SC and normal-state regions takes place in the underdoped regime as well as in the overdoped regime of LSCO.

2007-09-01

231

Semi-continuous in situ magnetic separation for enhanced extracellular protease production-modeling and experimental validation.  

UK PubMed Central (United Kingdom)

In modern biotechnology proteases play a major role as detergent ingredients. Especially the production of extracellular protease by Bacillus species facilitates downstream processing because the protease can be directly harvested from the biosuspension. In situ magnetic separation (ISMS) constitutes an excellent adsorptive method for efficient extracellular protease removal during cultivation. In this work, the impact of semi-continuous ISMS on the overall protease yield has been investigated. Results reveal significant removal of the protease from Bacillus licheniformis cultivations. Bacitracin-functionalized magnetic particles were successfully applied, regenerated and reused up to 30 times. Immediate reproduction of the protease after ISMS proved the biocompatibility of this integrated approach. Six subsequent ISMS steps significantly increased the overall protease yield up to 98% because proteolytic degradation and potential inhibition of the protease in the medium could be minimized. Furthermore, integration of semi-continuous ISMS increased the overall process efficiency due to reduction of the medium consumption. Process simulation revealed a deeper insight into protease production, and was used to optimize ISMS steps to obtain the maximum overall protease yield.

Cerff M; Scholz A; Käppler T; Ottow KE; Hobley TJ; Posten C

2013-08-01

232

A rapid method for detection of genetically modified organisms based on magnetic separation and surface-enhanced Raman scattering.  

UK PubMed Central (United Kingdom)

In this study, a new method combining magnetic separation (MS) and surface-enhanced Raman scattering (SERS) was developed to detect genetically modified organisms (GMOs). An oligonucleotide probe which is specific for 35 S DNA target was immobilized onto gold coated magnetic nanospheres to form oligonucleotide-coated nanoparticles. A self assembled monolayer was formed on gold nanorods using 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) and the second probe of the 35 S DNA target was immobilized on the activated nanorod surfaces. Probes on the nanoparticles were hybridized with the target oligonucleotide. Optimization parameters for hybridization were investigated by high performance liquid chromatography. Optimum hybridization parameters were determined as: 4 ?M probe concentration, 20 min immobilization time, 30 min hybridization time, 55 °C hybridization temperature, 750 mM buffer salt concentration and pH: 7.4. Quantification of the target concentration was performed via SERS spectra of DTNB on the nanorods. The correlation between the target concentration and the SERS signal was found to be linear within the range of 25-100 nM. The analyses were performed with only one hybridization step in 40 min. Real sample analysis was conducted using Bt-176 maize sample. The results showed that the developed MS-SERS assay is capable of detecting GMOs in a rapid and selective manner.

Guven B; Boyac? ?H; Tamer U; Çal?k P

2012-01-01

233

The effects of magnetic separation on cryopreserved bovine spermatozoa motility, viability and cryo-capacitation status.  

UK PubMed Central (United Kingdom)

Summary Cryopreservation is a technique used to preserve cells for long-time storage. It is widely used in agriculture to store male gametes in liquid nitrogen. The aim of this study was to determine the optimum thawing temperature and time for samples subjected to annexin V magnetic-activated cell sorting (AnMACS) as the sperm preparation technique. Pooled semen samples from three ejaculates were divided into two groups. The treatment group was subjected both to AnMACS and to being cryopreserved, whilst the control group was cryopreserved directly without MACS. Post-thaw analysis was carried out for samples thawed at either 20°C for 13 s, 37°C for 30 s, 40°C for 7 s, 60°C for 6 s or 80°C for 5 s. Sperm kinematics, viability and capacitation status were determined for samples subjected to all thawing temperatures described. Results showed that thawing at 37°C for 13 s for MACS-processed samples was a superior option compared with other thawing procedures; there was a significant difference in P < 0.05 values for curvilinear velocity (VCL ?m/s) and sperm straightness (STR %) when samples were thawed at 40°C for 7 s, with fewer capacitated spermatozoa (P < 0.05) when samples were thawed at 37°C for 30 s, 40°C for 7 s or 60°C for 6 s. Hence, we can speculate that the use of AnMACS as the sperm preparation technique can somehow enhance sperm cryosurvival rate after cryopreservation, however the fertilization potential of these cells has yet to be determined.

Faezah SS; Zuraina FM; Farah JH; Khairul O; Hilwani NI; Iswadi MI; Fang CN; Zawawi I; Abas OM; Fatimah SI

2012-12-01

234

Separation and characterization of alkyl phenol formaldehyde resins demulsifier by adsorption chromatography, gel permeation chromatography, infrared spectrometry and nuclear magnetic resonance spectroscopy  

International Nuclear Information System (INIS)

[en] This paper deals with the separation and characterization of alkyl phenol formaldehyde resins demulsifier by infrared spectrometry and nuclear magnetic resonance spectroscopy after separation of the different surfactants and low molecular additives by adsorption chromatography. Firstly, the types of surfactants are identified by methylene blue chloride-chloroform test method and the elemental analysis such as Ca, K, Mg, Na, P, S and N. Then, the different surfactants and low molecular components are separated by adsorption chromatography after parts of low molecular components are dried in an oven, and the molecular weight distribution is measured by gel permeation chromatography also. Finally, the separated surfactants are determined by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectroscopy. The distortionless enhancement by polarization transfer (DEPT), H, C correlated spectroscopy (H, C-COSY), H, H correlated spectroscopy (H, H-COSY) and heteronuclear multiple-bond correlation (HMBC) spectroscopy are applied to determine the molecular structures

2006-05-04

235

Tandem Assays of Protein and Glucose with Functionalized Core/Shell Particles Based on Magnetic Separation and Surface-Enhanced Raman Scattering.  

UK PubMed Central (United Kingdom)

Tandem assays of protein and glucose in combination with mannose-functionalized Fe3 O4 @SiO2 and Ag@SiO2 tag particles have promising potential in effective magnetic separation and highly sensitive and selective SERS assays of biomaterials. It is for the first time that tandem assay of glucose is developed using SERS based on the Con A-sandwiched microstructures between the functionalized magnetic and tag particles.

Kong X; Yu Q; Lv Z; Du X

2013-04-01

236

Design of a core-shell type immuno-magnetic separation system and multiplex PCR for rapid detection of pathogens from food samples.  

Science.gov (United States)

We report an immuno-magnetic separation system developed by the immobilization of pathogen-specific antibodies on the core-shell magnetic beads. The magnetic beads were grafted with glycidylmethacrylate (GMA) using surface-initiated atom transfer radical polymerization (SI-ATRP). For immuno-magnetic separation (IMS) of target bacterial cells from others, antibodies for Escherichia coli and Salmonella enterica serovar Typhimurium cells were immobilized on the magnetic beads via glutaraldehyde coupling reaction. Our IMS system successfully separated Salmonella cells when the concentrations of target (i.e., Salmonella) and interfering (i.e., E. coli) cells were at the same level. Polymerase chain reaction (PCR) assays amplifying the rfb/rfbE region of the E. coli genome and a 647-bp fragment of the invA region of Salmonella were performed as the specific selection to accurately confirm the presence of E. coli and Salmonella, respectively. IMS and multiplex PCR methods can be used for specific and quantitative detection of pathogens from food samples. Thus, this study developed a reliable and direct system for rapid detection of Salmonella and E. coli in food samples. In addition, IMS method could be easily adapted to detect other pathogens by selecting the pertinent antibody. PMID:24048640

Ozalp, V Cengiz; Bayramoglu, Gulay; Arica, M Yakup; Oktem, H Avni

2013-09-19

237

Selective separation and enrichment of glibenclamide in health foods using surface molecularly imprinted polymers prepared via dendritic grafting of magnetic nanoparticles.  

UK PubMed Central (United Kingdom)

In this paper, the novel surface molecularly imprinted polymers based on dendritic-grafting magnetic nanoparticles were developed to enrich and separate glibenclamide in health foods. The density functional theory method was used to give theoretical directions to the synthesis of molecularly imprinted polymers. The polymers were prepared by using magnetic nanoparticles as supporting materials, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The characteristics of magnetic nanoparticles and polymers were measured by transmission electron microscope and SEM, respectively. The enriching ability of molecularly imprinted polymers was measured by Freundlich Isotherm. The molecularly imprinted polymers were used as dispersive SPE materials to enrich, separate, and detect glibenclamide in health foods by HPLC. The average recoveries of glibenclamide in spiked health foods were 81.46-93.53% with the RSD < 4.07%.

Wang R; Wang Y; Xue C; Wen T; Wu J; Hong J; Zhou X

2013-03-01

238

Production and evaluation of the utility of novel phage display-derived peptide ligands to Salmonella spp. for magnetic separation.  

UK PubMed Central (United Kingdom)

AIMS: The objectives of this study were to produce Salmonella-specific peptide ligands by phage display biopanning and evaluate their use for magnetic separation (MS). METHODS AND RESULTS: Four-phage display biopanning rounds were performed, and the peptides expressed by the two most Salmonella-specific (on the basis of phage-binding ELISA results) phage clones, MSal020401 and MSal020417, were chemically synthesized and coupled to MyOne™ tosylactivated Dynabeads(®). Peptide capture capability for whole Salmonella cells from nonenriched broth cultures was quantified by MS + plate counts and MS + Greenlight™ detection and compared to capture capability of anti-Salmonella (antibody-coated) Dynabeads(®). MS + Greenlight™ gave a more comprehensive picture of capture capability than MS + plate counts and showed that Peptide MSal020417-coated beads exhibited at least similar, if not better, capture capability to anti-Salmonella Dynabeads(®) (mean capture values of 36·0 ± 18·2 and 31·2 ± 20·1%, respectively, over Salmonella spp. concentration range 3 × 10(1) -3 × 10(6) CFU ml(-1)) with cross-reactivity of ?1·9% to three other foodborne pathogens: Escherichia coli, Listeria monocytogenes and Campylobacter jejuni. CONCLUSIONS: One of the phage display-derived peptide ligands was demonstrated by MS + Greenlight™ to be a viable antibody alternative for MS of Salmonella spp. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates an antibody-free approach to Salmonella detection and opens substantial possibilities for more rapid tests for this bacterium.

Morton J; Karoonuthaisiri N; Stewart LD; Oplatowska M; Elliott CT; Grant IR

2013-07-01

239

A novel magnetically separable gamma-Fe2O3/crosslinked chitosan adsorbent: preparation, characterization and adsorption application for removal of hazardous azo dye.  

UK PubMed Central (United Kingdom)

A novel magnetically separable adsorbent, namely magnetic gamma-Fe(2)O(3)/crosslinked chitosan composites (Mgamma-Fe(2)O(3)/CSCs), was prepared by microemulsion process and characterized by XRD, FT-IR, TGA, DSC, SEM and VSM. Adsorption of methyl orange (MO), used as a model pollutant, from aqueous solution on Mgamma-Fe(2)O(3)/CSCs was investigated. Characterization results indicated that magnetic gamma-Fe(2)O(3) nanoparticles have been introduced in Mgamma-Fe(2)O(3)/CSCs and kept intrinsic magnetic properties. The saturated magnetization (sigma(s)) of Mgamma-Fe(2)O(3)/CSCs can be expediently adjusted by changing additive dosage of gamma-Fe(2)O(3). Adsorption results showed that both nanocomposite adsorbents with weight ratio of gamma-Fe(2)O(3) to chitosan of 1:10 and 2:5 exhibited higher adsorption capacities and attained adsorption equilibria in shorter time compared with crosslinked chitosan. After adsorption, Mgamma-Fe(2)O(3)/CSCs were effectively separated from reaction solution in 10s by applying an adscititious magnetic field. Adsorption kinetics of MO on 1:10 Mgamma-Fe(2)O(3)/CSCs followed the pseudo-second-order kinetic model. Effects of both initial pH and adsorbent dosage on the adsorption of MO were remarkable in experimental conditions.

Zhu HY; Jiang R; Xiao L; Li W

2010-07-01

240

In-plane magnetic pattern separation in NiFe/NiO and Co/NiO exchange biased bilayers investigated by magnetic force microscopy  

Science.gov (United States)

Ion bombardment induced magnetic patterning (IBMP) was used to write in-plane magnetized micro and submicron patterns in exchange biased magnetic bilayers, where the magnetization directions of the adjacent patterns are antiparallel to each other in remanence. These magnetic patterns were investigated by non-contact magnetic force microscopy (MFM). It is shown that the recorded MFM images of the IBMP patterns in two exemplarily chosen standard layer systems (NiFe(4.8nm)/NiO(68nm) and Co(4.8nm)/NiO(68nm)) can be well described by a model within the point-dipole approximation for the tip magnetization. For 5 and 0.9?m wide bar patterns the domain wall widths between adjacent magnetically patterned areas were determined to a~1?m. The minimum magnetically stable pattern width was estimated to be 0.7?m in the standard system Co(4.8nm)/NiO(68nm).

Ehresmann, A.; Krug, I.; Kronenberger, A.; Ehlers, A.; Engel, D.

2004-09-01

 
 
 
 
241

In-plane magnetic pattern separation in NiFe/NiO and Co/NiO exchange biased bilayers investigated by magnetic force microscopy  

International Nuclear Information System (INIS)

Ion bombardment induced magnetic patterning (IBMP) was used to write in-plane magnetized micro and submicron patterns in exchange biased magnetic bilayers, where the magnetization directions of the adjacent patterns are antiparallel to each other in remanence. These magnetic patterns were investigated by non-contact magnetic force microscopy (MFM). It is shown that the recorded MFM images of the IBMP patterns in two exemplarily chosen standard layer systems (NiFe (4.8 nm)/NiO (68 nm) and Co (4.8 nm)/NiO (68 nm)) can be well described by a model within the point-dipole approximation for the tip magnetization. For 5 and 0.9 ?m wide bar patterns the domain wall widths between adjacent magnetically patterned areas were determined to a?1 ?m. The minimum magnetically stable pattern width was estimated to be 0.7 ?m in the standard system Co (4.8 nm)/NiO (68 nm)

2004-01-01

242

Phase separation and suppression of critical dynamics at quantum transitions of itinerant magnets: MnSi and (Sr$_{1-x}$Ca$_{x}$)RuO$_{3}$  

CERN Multimedia

Quantum phase transitions (QPTs) have been studied extensively in correlated electron systems. Characterization of magnetism at QPTs has, however, been limited by the volume-integrated feature of neutron and magnetization measurements and by pressure uncertainties in NMR studies using powderized specimens. Overcoming these limitations, we performed muon spin relaxation ($\\mu$SR) measurements which have a unique sensitivity to volume fractions of magnetically ordered and paramagnetic regions, and studied QPTs from itinerant heli/ferro magnet to paramagnet in MnSi (single-crystal; varying pressure) and (Sr$_{1-x}$Ca$_{x}$)RuO$_{3}$ (ceramic specimens; varying $x$). Our results provide the first clear evidence that both cases are associated with spontaneous phase separation and suppression of dynamic critical behavior, revealed a slow but dynamic character of the ``partial order'' diffuse spin correlations in MnSi above the critical pressure, and, combined with other known results in heavy-fermion and cuprate sy...

Uemura, Y J; Gat-Malureanu, I M; Carlo, J P; Russo, P L; Savici, A T; Aczel, A; MacDougall, G J; Rdoriguez, J A; Luke, G M; Dunsiger, S R; McCollam, A; Arai, J; Pfleiderer, C; Böni, P; Yoshimura, K; Baggio-Saitovitch, E; Fontes, M B; Sushko, Y V; Sereni, J; Pfleiderer, Ch.

2006-01-01

243

O-Allylation of phenols with allylic acetates in aqueous media using a magnetically separable catalytic system  

Science.gov (United States)

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 ...

244

Magnetically separable hybrid CdS-TiO2-Fe3O4 nanomaterial: Enhanced photocatalystic activity under UV and visible irradiation  

Science.gov (United States)

Magnetically separable photocatalyst of TiO2-CdS-Fe3O4@SiO2 nanocomposite was successfully prepared through a microwave heating method. The products exhibit enhanced photocatalystic activity which is more efficient than that of pure CdS and Degussa P25 TiO2 toward the degradation of RhB under both UV and visible irradiation. This is attributed to the charge separation and transformation from CdS to TiO2. The hysteresis loop of TiO2-CdS-Fe3O4@SiO2 nanocomposite indicates an excellent magnetic property with the saturated magnetization of 9 emu/g. We also show the fast magnetic separation behaviour of the TiO2-CdS-Fe3O4@SiO2 nanocomposite to remove and recycle the photocatalyst from the solution. These indicate TiO2-CdS-Fe3O4@SiO2 nanocomposite is an effective and convenient recyclable photocatalyst.

Bian, Xiaofang; Hong, Kunquan; Liu, Liqing; Xu, Mingxiang

2013-09-01

245

Separation of species of a binary fluid mixture confined between two concentric rotating circular cylinders in presence of a strong radial magnetic field  

Science.gov (United States)

The effect of a radial magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids confined between two concentric rotating circular cylinders with different angular velocity is examined. The equations governing the motion, temperature and concentration in cylindrical polar coordinate are solved analytically. The solution obtained in closed form for concentration distribution is plotted against the radial distances from the surface of the inner circular cylinder for various values of non-dimensional parameters. It is found that the non-dimensional parameters viz. the Hartmann number, thermal diffusion number, baro diffusion number, rotational Reynolds number, the product of Prandtl number and Eckert number, magnetic Prandtl number and the ratio of the angular velocities of inner and outer cylinders affects the species separation of rarer and lighter component significantly. The problem discussed here derives its application in the basic fluid dynamics separation processes to separate the rarer component of the different isotopes of heavier molecules where electromagnetic method of separation does not work.

Sharma, B. R.; Singh, R. N.

2010-08-01

246

Isolation of prostate cancer cell subpopulations of functional interest by use of an on-chip magnetic bead-based cell separator  

Science.gov (United States)

This work presents the design, fabrication and characterization of a modular magnetic bead-based cell separation device developed for the sequential sorting of a heterogeneous prostate cancer (CaP) cell population. The chief aim is cell sorting carried out on the basis of surface marker expression, serially selecting cellular subpopulations for capture by the use of antibody-coated magnetic beads. The markers of interest, prostate specific membrane antigen (PSMA) and CD10 were selected for their relevance to ongoing CaP development research. The separation device was fabricated out of plastic, by the use of cyclic olefin copolymer (COC) injection molding, nickel-iron electroplating and thermoplastic fusion bonding. Effective depletion and enrichment of cell subsets based on multiple surface markers was achieved. Various flow rates and incubation times were tested for optimizing the sorting procedure.

Estes, Matthew D.; Ouyang, Bin; Ho, Shuk-mei; Ahn, Chong H.

2009-09-01

247

In-plane magnetic pattern separation in NiFe/NiO and Co/NiO exchange biased bilayers investigated by magnetic force microscopy  

Energy Technology Data Exchange (ETDEWEB)

Ion bombardment induced magnetic patterning (IBMP) was used to write in-plane magnetized micro and submicron patterns in exchange biased magnetic bilayers, where the magnetization directions of the adjacent patterns are antiparallel to each other in remanence. These magnetic patterns were investigated by non-contact magnetic force microscopy (MFM). It is shown that the recorded MFM images of the IBMP patterns in two exemplarily chosen standard layer systems (NiFe (4.8 nm)/NiO (68 nm) and Co (4.8 nm)/NiO (68 nm)) can be well described by a model within the point-dipole approximation for the tip magnetization. For 5 and 0.9 {mu}m wide bar patterns the domain wall widths between adjacent magnetically patterned areas were determined to a{approx}1 {mu}m. The minimum magnetically stable pattern width was estimated to be 0.7 {mu}m in the standard system Co (4.8 nm)/NiO (68 nm)

Ehresmann, A. E-mail: arnauld@rhrk.uni-kl.de; Krug, I.; Kronenberger, A.; Ehlers, A.; Engel, D

2004-09-01

248

Influence of the static high magnetic field on the liquid-liquid phase separation during solidifying the hyper-monotectic alloys  

Science.gov (United States)

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

249

Magnetic phase separation in La0.67Ca0.37Mn0.9Fe0.1O3: a Moessbauer study  

International Nuclear Information System (INIS)

Moessbauer measurement of La0.67Ca0.33Mn0.9Fe0.1O3 have been carried out from room temperature to 4.2 K with an applied magnetic fields. Moessbauer paramagnetic spectra of La0.67Ca0.33Mn0.9Fe0.1O3 were split into two doublets, even though Fe occurs at equivalent sites. Moessbauer spectra reveal that Fe substitutes for Mn as Fe3+. Moessbauer spectroscopy shows phase separation, both above and below the magnetic transition temperature (Tc). Below Tc, the spin orderings in the two phases are ferromagnetic (FM) and spin glass (SG) orderings, respectively. At low temperatures, SG phase converts into FM phase when the applied magnetic field increases. but only partially. (author)

2007-01-01

250

Electronic phase separation and magnetic order in the cobalt doped RFe2-xCoxAs2 (R=Sr, Eu) iron pnictide superconductors  

International Nuclear Information System (INIS)

We have investigated the magnetic and superconducting properties of RFe2-xCoxAs2 with R=Sr, Eu and 0?x?0.4 by means of muon spin relaxation (?+SR) and Moessbauer spectroscopy. Under ambient pressure the antiferromagnetic ordering temperature, TN of SrFe2-xCoxAs2 decreases with increasing Co-doping. However, TN remains finite even as superconductivity appears as a function of doping. This shows that electronic phase separation plays a role in this system. High pressure experiments show a reduction the magnetic ordering temperature by pressure. On the contrary, EuFe2-xCoxAs2 does not show superconductivity under ambient pressure but a peculiar interplay of the rare earth and iron magnetic order as a function of the Co-doping level.

2009-01-01

251

Novel Phase Separation and Magnetic Volume Tuning in Underdoped NaFe1-xCoxAs (x ˜0.01)  

Science.gov (United States)

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

252

Preparations and photocatalytic degradation of methyl orange in water on magnetically separable Bi12TiO20 supported on nickel ferrite  

Directory of Open Access Journals (Sweden)

Full Text Available A magnetically separable photocatalyst Bi12TiO20/SiO2/NiFe2O4 (BSN) with a typical ferromagnetic hysteresis was prepared by a simple process: the magnetic 200 wt% SiO2/NiFe2O4 (SN) dispersion prepared by a liquid catalytic phase transformation method and the visible-light-active photocatalyst Bi12TiO20 prepared by a simple coprecipitation processing were mixed, sonificated, dried, and calcined at 550 °C. The prepared photocatalyst showed high photocatalytic activity for the degradation of methyl orange in water under UV irradiation and visible-light irradiation (?>400 nm), and it was easy to be separated from a slurry-type photoreactor under the application of an external magnetic field, being one of promising photocatalysts for wastewater treatment. Transmission electron microscope (TEM) and X-ray diffractometer (XRD) were used to characterize the structure of the photocatalyst, indicating that the magnetic SN particles adhered to the surface of the Bi12TiO20 congeries. SiO2 layer round the surface of NiFe2O4 nanoparticles prevented effectively the injection of charges from TiO2 particles to NiFe2O4, which gave rise to the increase in photocatalytic activity.

Shihong Xu, Wenfeng Shangguan, Jian Yuan, Jianwei Shi and Mingxia Chen

2007-01-01

253

Separation/preconcentration of trace amounts of Cr, Cu and Pb in environmental samples by magnetic solid-phase extraction with Bismuthiol-II-immobilized magnetic nanoparticles and their determination by ICP-OES.  

Science.gov (United States)

A new method for separation/preconcentration of trace amounts of Cr, Cu and Pb in environmental samples by magnetic solid-phase extraction (SPE) with Bismuthiol-II-immobilized magnetic nanoparticles and their determination by ICP-OES has been developed. The separation of the target analytes from the aqueous solution containing the target analytes and Bismuthiol-II-immobilized magnetic nanoparticles was simply achieved by applying external magnetic field. Optimal experimental conditions including pH, sample volume, eluent concentration and volume and co-existing ions have been studied and established. Under the optimal experimental conditions, the detection limits for Cr, Cu and Pb with enrichment factors of 96, 95 and 87 were found to be 0.043, 0.058 and 0.085 ngmL(-1) and their relative standard deviations (R.S.D.s) were 3.5%, 4.6% and 3.7% (n=5, C=2 ngmL(-1)), respectively. The method was validated with certified reference material (GBW50009-88) of environmental water sample and the analytical results coincided well with the certified values. Furthermore, the method was successfully applied to the determination of target analytes in river and lake water samples. Compared with established methods, the proposed method is characterized with high enrichment factor, fast separation and low detection limits. PMID:19159767

Suleiman, Jibrin Sabo; Hu, Bin; Peng, Hanyong; Huang, Chaozhang

2008-10-14

254

Separation/preconcentration of trace amounts of Cr, Cu and Pb in environmental samples by magnetic solid-phase extraction with Bismuthiol-II-immobilized magnetic nanoparticles and their determination by ICP-OES.  

UK PubMed Central (United Kingdom)

A new method for separation/preconcentration of trace amounts of Cr, Cu and Pb in environmental samples by magnetic solid-phase extraction (SPE) with Bismuthiol-II-immobilized magnetic nanoparticles and their determination by ICP-OES has been developed. The separation of the target analytes from the aqueous solution containing the target analytes and Bismuthiol-II-immobilized magnetic nanoparticles was simply achieved by applying external magnetic field. Optimal experimental conditions including pH, sample volume, eluent concentration and volume and co-existing ions have been studied and established. Under the optimal experimental conditions, the detection limits for Cr, Cu and Pb with enrichment factors of 96, 95 and 87 were found to be 0.043, 0.058 and 0.085 ngmL(-1) and their relative standard deviations (R.S.D.s) were 3.5%, 4.6% and 3.7% (n=5, C=2 ngmL(-1)), respectively. The method was validated with certified reference material (GBW50009-88) of environmental water sample and the analytical results coincided well with the certified values. Furthermore, the method was successfully applied to the determination of target analytes in river and lake water samples. Compared with established methods, the proposed method is characterized with high enrichment factor, fast separation and low detection limits.

Suleiman JS; Hu B; Peng H; Huang C

2009-03-01

255

Separate structure of two branches of sheared slab ?i mode and effects of plasma rotation shear in weak magnetic shear region  

International Nuclear Information System (INIS)

[en] The separate structure of two branches of the sheared slab ?i mode near the minimum-q magnetic surface is analysed and the effects of plasma rotation shears are considered in the weak magnetic shear region. Results show that the separation condition depends on the non-monotonous q profile and the deviation of rational surface from the minimum-q surface. Furthermore, it is found that the diamagnetic rotation shear may suppress the perturbation of the sheared slab ?i mode at one side of the minimum-q surface, the poloidal rotation shear from the sheared E-vector x B-vector flow has a similar role to the slab mode structure when it possesses a direction same as the diamagnetic shear. A plausible interrelation between the separate structures of the two branches of the sheared slab mode and the discontinuity or gap of the radially global structure of the drift wave near the minimum-q surface observed in the toroidal particle simulation (Kishimoto Y et al 1998 Plasma Phys. Control. Fusion 40 A663) is discussed. It seems to support such a viewpoint: the double or/and global branches of the sheared slab ?i mode near the minimum-q surface may become a bridge to connect the radially global structures of the drift wave at two sides of the minimum-q surface and the discontinuity may originate from the separate structures of these slab modes for a flatter q profile. (author)

2000-01-01

256

In vivo labeling and specific magnetic bead separation of RNA for biofilm characterization and stress-induced gene expression analysis in bacteria.  

UK PubMed Central (United Kingdom)

The method of in vivo labeling and separation of bacterial RNA was developed as an approach to elucidating the stress response of natural bacterial populations. This technique is based on the incorporation of digoxigenin-11-uridine-5'-triphosphate (DIG-11-UTP) in the RNA of active bacteria. The digoxigenin fulfills a dual role as a label of de novo synthesized RNA and a target for magnetic bead separation from a total RNA extract. Depending on the growth conditions and the population's composition, the assembly rate of DIG-11-UTP ranged from 1.2% to 12.5% of the total RNA in gram-positive and gram-negative reference bacteria as well as in natural biofilms from drinking water, surface water, and lake sediment. Separation of DIG-RNA from total RNA extracts was performed with a biotinylated anti-digoxigenin antibody and streptavidin-functionalized magnetic particles. The average separation yield from total RNA extracts was about 95% of labeled RNA. The unspecific bindings of non-labeled nucleic acids were smaller than 0.2%, as was evaluated by spiking experiments with an unmarked DNA amplicon. Applicability of the method developed was demonstrated by rRNA-directed PCR-DGGE population analysis of natural biofilms and expression profiling of two stress-induced genes (vanA and rpoS) in reference bacteria.

Stankiewicz N; Gold A; Yüksel Y; Berensmeier S; Schwartz T

2009-12-01

257

Separation of magnetic properties at uranium and cobalt sites in UCoAl using soft x-ray magnetic circular dichroism  

Science.gov (United States)

Temperature (T) and magnetic field (H) dependence of the magnetic properties in metamagnetic UCoAl have been investigated using a soft x-ray magnetic circular dichroism (XMCD). In order to extract element-specific magnetic properties at the U and Co sites, the XMCD experiment has been performed at the U 4d-5f (N4,5) and Co 2p-3d (L2,3) absorption edges, respectively. Directions of magnetic moments at the U and Co sites have been determined from shapes of the XMCD spectra. The directions of the total magnetic moments at the U and Co sites are parallel to the H direction (c axis), but the direction of the spin magnetic moment at the U site is opposite to that at the Co site. The XMCD intensities at both the U and Co sites at T=5.5 K increase steeply at H=0.77 T (Hm), corresponding to the metamagnetic transition. The XMCD intensities do not saturate, even in the field-induced ferromagnetic state above Hm. In addition, the ratio of the increase of the XMCD intensity at the Co site is smaller than that at the U site. From comparison of the H dependence of the XMCD intensities at T=25 and 5.5 K, we found that the magnetic behavior of the Co atom has a stronger T dependence than that of the U atom.

Takeda, Yukiharu; Saitoh, Yuji; Okane, Tetsuo; Yamagami, Hiroshi; Matsuda, Tatsuma D.; Yamamoto, Etsuji; Haga, Yoshinori; ?nuki, Yoshichika; Fisk, Zachary

2013-08-01

258

Possible magnetic phase separation in Ru-doped La{sub 0.67}Ca{sub 0.33}MnO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

X-ray diffraction, resistivity, AC susceptibility and magnetization studies on La{sub 0.67}Ca{sub 0.33}Mn{sub 1-x}Ru{sub x}O{sub 3} (0{<=}x<0.085) were carried out. A significant increase in the lattice parameters indicated the presence of mixed valence state of Ru: Ru{sup 3+} and Ru{sup 4+}. The resistivity of the doped compounds exhibited two features: a broad hump and a relatively sharp peak. While a para- to ferromagnetic transition could be observed for the latter peak, no magnetic signal either in AC susceptibility or in magnetization measurements could be observed for the broad hump. The magnetic moment of Mn per unit cell decreases non-linearly from 3.55 to 3 {mu}{sub B} for the Ru compositions studied. Based on the results of the present studies and existing literature on Mn-site substituted systems, we argue that a magnetic phase separation occurs in the Ru-doped system. While the sharp peak in the resistivity corresponds to Ru{sup 4+}-enriched regions with ferromagnetic coupling of Ru with the neighboring Mn ions, the broad peak corresponds to Ru{sup 3+}-rich regions, with antiferromagnetic coupling of Ru with the neighboring Mn ions.

Seetha Lakshmi, L.; Sridharan, V. E-mail: varadu@igcar.ernet.insridh61@hotmail.com; Natarajan, D.V.; Chandra, Sharat; Sankara Sastry, V.; Radhakrishnan, T.S.; Pandian, Ponn; Justine Joseyphus, R.; Narayanasamy, A

2003-02-01

259

Synthesis of Fe3O4@poly(methylmethacrylate-co-divinylbenzene) magnetic porous microspheres and their application in the separation of phenol from aqueous solutions.  

Science.gov (United States)

A simple strategy to fabricate magnetic porous microspheres of Fe(3)O(4)@poly(methylmethacrylate-co-divinylbenzene) was demonstrated. The magnetic microspheres, consisting of polymer-coated iron oxide nanoparticles, were synthesized by the modified suspension polymerization of methacrylate and divinylbenzene in the presence of a magnetic fluid. The morphology and the properties of the magnetic porous microspheres were examined by scanning electron microscopy, transmission electron microscopy, superconducting quantum interference device, Fourier transform infrared spectroscopy, thermogravimetry, and X-ray powder diffraction. The pore size distribution and the specific surface area of the microspheres were measured by nitrogen sorption and mercury porosimetry technique. As predicted from the previous knowledge, the magnetic porous microspheres possessed a high specific surface area using n-hexane as a porogen. It was further found that the amounts of divinylbenzene and methacrylate, the ratio of porogens, and the dosage of ferrofluids affect the specific surface area of the microspheres. Furthermore, the microspheres were applied to remove phenol from aqueous solutions. The results showed that the microspheres had a high adsorption capacity for phenol and a high separation efficiency due to their porous structure, polar groups, and superparamagnetic characteristic. PMID:21601864

Tai, Yulei; Wang, Li; Gao, Jingmin; Amer, Wael A; Ding, Wenbing; Yu, Haojie

2011-05-04

260

Synthesis of Fe3O4@poly(methylmethacrylate-co-divinylbenzene) magnetic porous microspheres and their application in the separation of phenol from aqueous solutions.  

UK PubMed Central (United Kingdom)

A simple strategy to fabricate magnetic porous microspheres of Fe(3)O(4)@poly(methylmethacrylate-co-divinylbenzene) was demonstrated. The magnetic microspheres, consisting of polymer-coated iron oxide nanoparticles, were synthesized by the modified suspension polymerization of methacrylate and divinylbenzene in the presence of a magnetic fluid. The morphology and the properties of the magnetic porous microspheres were examined by scanning electron microscopy, transmission electron microscopy, superconducting quantum interference device, Fourier transform infrared spectroscopy, thermogravimetry, and X-ray powder diffraction. The pore size distribution and the specific surface area of the microspheres were measured by nitrogen sorption and mercury porosimetry technique. As predicted from the previous knowledge, the magnetic porous microspheres possessed a high specific surface area using n-hexane as a porogen. It was further found that the amounts of divinylbenzene and methacrylate, the ratio of porogens, and the dosage of ferrofluids affect the specific surface area of the microspheres. Furthermore, the microspheres were applied to remove phenol from aqueous solutions. The results showed that the microspheres had a high adsorption capacity for phenol and a high separation efficiency due to their porous structure, polar groups, and superparamagnetic characteristic.

Tai Y; Wang L; Gao J; Amer WA; Ding W; Yu H

2011-08-01

 
 
 
 
261

Magnetic field dependence of the magnetic phase separation in Pr1-xCaxMnO3 manganites studied by small-angle neutron scattering  

CERN Document Server

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 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 place at different scales. At the mesoscopic scale (200nm), the inhomogeneities correspond to the percolation of the conducting ferromagnetic phase into the insulating phases. It is at the origin of the colossal magnetoresistance of the compound. The other inhomogeneities are nanoscopic: inside the antiferromagnetic phase (AFI), there exist small ferromagnetic clusters. Inside the ferromagnetic phase which exists in absence of magnetic field in some compounds and is in fact insulating (FI), there also exist small non ferromagnetic objects. No evolution of this nanostruct...

Saurel, D; Heinemann, A; Martin, C; Mercone, S; Simon, C; Saurel, Damien; Brulet, Annie; Heinemann, Andre; Martin, Christine; Mercone, Silvana; Simon, Charles

2006-01-01

262

Magnetism  

Science.gov (United States)

Students investigate magnetism and which materials are attracted by magnets. Students describe the behavior of atoms in a magnet and explain why specific materials are or are not attracted to a magnet. The discussion questions explore several domains of science and relate them to magnetism.

Discovery

2009-06-23

263

A quantitative determination of magnetic nanoparticle separation using on-off field operation of quadrupole magnetic field-flow fractionation (QMgFFF).  

UK PubMed Central (United Kingdom)

Quadrupole Magnetic Field-Flow Fractionation (QMgFFF) is a technique for characterization of sub-micrometer magnetic particles based on their retention in the magnetic field from flowing suspensions. Different magnetic field strengths and volumetric flow rates were tested using on-off field application and two commercial nanoparticle preparations that significantly differed in their retention parameter, ? (by nearly 8-fold). The fractograms showed a regular pattern of higher retention (98.6% v. 53.3%) for the larger particle (200 nm v. 90 nm) at the higher flow rate (0.05 mL/min v. 0.01 mL/min) at the highest magnetic field (0.52 T), as expected because of its lower retention parameter. The significance of this approach is a demonstration of a system that is simpler in operation than a programmed field QMgFFF in applications to particle mixtures consisting of two distinct particle fractions. This approach could be useful for detection of unwanted particulate contaminants, especially important in industrial and biomedical applications.

Orita T; Moore LR; Joshi P; Tomita M; Horiuchi T; Zborowski M

2013-01-01

264

Magnetic field structure effect on the spatial flow in a supersonic MHD generator with boundary layer separation  

International Nuclear Information System (INIS)

Calculational experiment for evaluating the role of the inhomogeneous two-component magnetic field constants in the MHD-channel is carried out. Difference of the medium-integral magnetic induction from the values on the axis is within the range of 2 up 4%. It is shown that availability of additional component of the magnetic field in the electrode direction in the channel cross sections intensifies the secondary flows and thereby increases the danger of the boundary layers break-off. The negative effect of the additional component by the beginning of the break-off regime is surpassed by stabilizing effect from decrease in the basic component to electrodes. By developed break-off flow the effects related to the availability of the additional component are prevailing

1999-01-01

265

Attenuation of morphine-induced analgesia in mice by exposure to magnetic resonance imaging: separate effects of the static, radiofrequency and time-varying magnetic fields.  

UK PubMed Central (United Kingdom)

Exposure of adult male mice to a magnetic resonance imaging (MRI) procedure has been shown to abolish the nocturnal analgesic responses observed following treatment with morphine. The field component(s) responsible for this inhibitory effect were examined by exposing mice to either the static, time-varying or rf magnetic field components associated with an MRI procedure. In the middle of the night portion of their day-night cycle, mice were exposed for 23.2 min to one of the above field components, intraperitoneally injected with morphine sulphate (10 mg/kg) and then exposed to the field conditions for another 23.2 min, after which analgesic responses were determined. Analgesia was quantitated by determining the length of time mice were content to be on a hot surface (50 degrees C) before they showed discomfort by licking their paws. It was observed that the time-varying magnetic field completely abolished, the rf field significantly reduced, while the static field component (0.15 T) had no evident effect on morphine-induced analgesia. These results indicate that the time-varying, and to a lesser extent the rf, fields associated with the MRI procedure inhibit morphine-induced analgesia in mice. These data also raise the possibility that exposure in humans to some of the magnetic field components associated with MRI may have clinically relevant effects on the actions of narcotic drugs such as morphine.

Prato FS; Ossenkopp KP; Kavaliers M; Sestini E; Teskey GC

1987-01-01

266

Preparation of silanized magnetic nanoparticles for magnetic separation technique use; Preparacao de nanoparticulas magneticas silanizadas para utilizacao em tecnicas de separacao magnetica  

Energy Technology Data Exchange (ETDEWEB)

Superparamagnetic particles of magnetite were functionalized with 3-aminopropyltriethoxysilane by direct silanization to provide the modified magnetic nanoparticles. They are characterized by scanning and transmission electron microscopy, infrared absorption spectroscopy and by the thermogravimetry. The characterizations by infrared absorption spectroscopy and thermogravimetry confirmed the functionalization. The adsorption capacity of the silanized magnetite and equilibrium isotherm of Eu (III) ions from nitric solution were determined. (author)

Yamaura, Mitiko; Camilo, Ruth Luqueze; Moura, Eduardo de; Santos, Bruno Zolotareff [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

2002-07-01

267

[Identification of Env-specific monoclonal antibodies from Chinese HIV-1 infected person by magnetic beads separating B cells and single cell RT-PCR cloning].  

UK PubMed Central (United Kingdom)

OBJECTIVE: To establish a simple and practical method for screening of Env-specific monoclonal antibodies from HIV-1 infected individuals. METHODS: Human B cells were purified by negative sorting from PBMCs and memory B cells were further enriched using anti-CD27 microbeads. Gp120 antigen labbled with biotin was incubated with memory B cells to specifically bind IgG on cells membrane. The memory B cells expressing the Env-specific antibody were harvested by magnetic beads separating, counted and diluted to the level of single cell in each PCR well that loading with catch buffer containing RNase inhibitor to get RNAs. The antibody genes were amplified by single cell RT-PCR and nested PCR, cloned into eukaryotic expression vectors and transfected into 293T cells. The binding activity of recombinant antibodies to Env were tested by ELISA. RESULTS: Three monocolonal Env-specific antibodies were isolated from one HIV-1 infected individual. CONCLUSION: We can obtain Env-specific antibody by biotin labbled antigen, magnetic beads separating technique coupled with single cell RT-PCR and expression cloning.

Huang XY; Yu SQ; Cheng Z; Ye JR; Xu K; Feng X; Zeng Y

2013-04-01

268

Thermodynamic calculations of phase equilibria of Co-Cr-Pt ternary system and magnetically induced phase separation in the FCC and HCP phases  

Science.gov (United States)

The calculations of phase equilibria of the Co-Cr-Pt ternary system have been carried out based on the thermodynamic assessments of Co-Cr, Co-Pt and Cr-Pt binary systems by the calculation of phase diagram technique. The Gibbs energies of the liquid, FCC, BCC and HCP solution phases were approximated by a sub-regular solution model, while those of /? and Cr3Pt phases were approximated by a compound energy model. Almost all the experimental information on each sub-system has been well described by the present set of thermodynamic parameters. A critical calculation of the magnetically induced miscibility gap between the ferromagnetic HCP and the paramagnetic HCP phase has been conducted, where the two-phase separation has been found at the Curie temperature. The Cr content in the ferromagnetic HCP phase increases and the width of the two-phase separation becomes narrower with increasing Pt content. The present calculations would be useful for the design and development of the perpendicular magnetic recording media.

Oikawa, K.; Qin, G. W.; Ikeshoji, T.; Kitakami, O.; Shimada, Y.; Ishida, K.; Fukamichi, K.

2001-10-01

269

Magnetic affinity microspheres with meso-/macroporous shells for selective enrichment and fast separation of phosphorylated biomolecules.  

UK PubMed Central (United Kingdom)

The flowerlike multifunctional affinity microspheres prepared by a facile solvothermal synthesis and subsequent calcination process consist of magnetic cores and hierarchical meso-/macroporous TiO2 shells. The hierarchical porous structure of the flowerlike affinity microspheres is constructed by the macroporous shell from the stacked mesoporous nanopetals which are assembled by small crystallites. The affinity microspheres have a relatively large specific surface area of 50.45 m(2) g(-1) and superparamagnetism with a saturation magnetization (Ms) value of 30.1 emu g(-1). We further demonstrate that they can be applied for rapid and effective purification of phosphoproteins, in virtue of their selective affinity, porous structure, and strong magnetism. In addition, the affinity microspheres can also be used for enrichment of phosphopeptides, and the selectivity is greatly improved due to the increase of mass transport and prevention of the possible "shadow effect" resulting from the smaller and deeper pores by taking advantage of the unique porous structure. Overall, this work will be highly beneficial for future applications in the isolation and identification of phosphorylated biomolecules.

Cheng G; Wang ZG; Liu YL; Zhang JL; Sun DH; Ni JZ

2013-04-01

270

Magnetic Th(IV)-ion imprinted polymers with salophen schiff base for separation and recognition of Th(IV)  

International Nuclear Information System (INIS)

A new complex of N,N'-bis(3-allyl salicylidene)o-phenylenediamine and thorium(IV) (Th(IV)) was synthesized and used as the functional monomer for a novel Th(IV) magnetic ion-imprinted polymer; this polymer was synthesized using a surface imprinting technique that included the modified magnetic Fe3O4 particle and used tetraethyl orthosilicate, 3-Aminopropyltriethoxysilane and maleic anhydride in the process. The magnetic polymer was characterized using FT-IR, and powder- and single crystal-XRD. The behavior of Th(IV) was investigated using batch experiments. At pH 4.5, the uptake capacity of this adsorbent and that of the non-imprinted polymer was 42.54 and 14.10 mg g-1, respectively, and the relative selectivity coefficient values of the synthesized adsorbent for Th(IV)/La(III), Th(IV)/Ce(III), Th(IV)/Nd(III), and Th(IV)/U(VI) were 82.2, 93.1, 21.0 and 62.4 times greater than that of the non-imprinted matrix, respectively. In addition, the Th(IV) adsorption process using Fe3O4aSiO2-IIP follows pseudo-second-order reaction kinetics and the Langmuir adsorption isotherm. The thermodynamic parameters also suggest that the adsorption of Th(IV) onto Fe3O4aSiO2-IIPs was a spontaneous and endothermic process. (author)

2013-01-01

271

Using shell-tunable mesoporous Fe3O4-HMS and magnetic separation to remove DDT from aqueous media  

International Nuclear Information System (INIS)

1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) is of concern in water treatment because of its persistence and health effects. A new concept is proposed to synthesize hexagonal mesoporous silica (HMS) with magnetic functionalization for DDT removal from aqueous media. Fe3O4 nanocrystals were synthesized by a low-temperature solvothermal process, and then encapsulated in mesoporous silica through a packing approach, forming core-shell structured Fe3O4-HMS microspheres. The synthesized materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen adsorption-desorption techniques. The results indicate that the silica shell conserves mesoporous structure after the removal of surfactant templates. Different from previous studies, the thickness, pore volume and surface area of silica shell can be controlled by adjusting the reaction condition. These Fe3O4-HMS materials show high adsorption capacity and fast adsorption rate for DDT. Because of the useful magnetic property and unique mesoporous structure, the synthesized materials provide a fast, convenient and highly efficient means to remove DDT from aqueous media.

2009-11-15

272

High efficiency annular magnetically insulated line oscillator-transit time oscillator with three separate frequencies in three bands  

Science.gov (United States)

To increase the efficiency of the magnetically insulated line oscillator (MILO) and expand its frequency band, a coaxial transit time oscillator (TTO) is introduced to use the load currents of an annular MILO, called the annular MILO-TTO, which comprises an inward-emitting MILO, an outward-emitting MILO, and a coaxial TTO. In simulation, when the input power is 78 GW and the diode voltage is 520 kV, three microwaves with powers of 3.2, 9.6, and 7.0 GW are generated, with a total efficiency of 25.4%, in the inward-emitting MILO, the outward-emitting MILO, and the coaxial TTO, and the frequencies are 1.7, 3.3, and 4.2 GHz, corresponding to L, S, and C bands, respectively.

Xiao, Renzhen; Sun, Jun; Chen, Changhua; Zhang, Yongpeng; Shao, Hao

2009-08-01

273

Separation of energy scales in the kagome antiferromagnet TmAgGe: a magnetic-field-orientation study up to 55 T  

CERN Multimedia

TmAgGe is an antiferromagnet in which the spins are confined to distorted kagome-like planes at low temperatures. We report angle-dependent measurements of the magnetization $M$ in fields of up to 55 T that show that there are two distinct and separate energy scales present in TmAgGe, each responsible for a set of step-like metamagnetic transitions; weak exchange interactions and strong crystalline electric field (CEF) interactions. Simulations of $M$ using a three-dimensional, free-energy minimization technique allow us to specify for the first time the physical origin of the metamagnetic transitions in low, in-plane fields. We also show that the transitions observed with the field perpendicular to the kagome planes are associated with the CEF-split multiplet of Tm.

Goddard, P A; Lima-Sharma, A L; Morosan, E; Blundell, S J; Budko, S L; Canfield, P C

2006-01-01

274

Potential environmental benefits of improving recycling of polyolefines – LCA of Magnetic density separation (MDS) developed in the EU FP7 funded project W2Plastic  

DEFF Research Database (Denmark)

The core of the EU FP7 funded project W2Plastic is development of a magnetic density separation (MDS) of polyolefines in order to improve the sorting efficiency of these polymer types in different waste fractions. As part of the project a life cycle assessment is performed in order to firstly identify eco-design criteria for the development and secondly to document the potential environmental improvement of polyolefin recycling using the MDS technology. A preliminary study focusing solely on the carbon footprint benefits of recycling plastic waste compared to virgin production of polymers showed that there are large benefits to recycling. However, including other uses of the waste illustrates that the benefits to a large extent depend on that the recycled plastic have such high quality that it can actually replace virgin plastic and also to some extent depends on which energy systems e.g. energy recovery from incineration substitutes.

Olsen, Stig Irving; Bonou, Alexandra

2012-01-01

275

Basic process development for separation of heavy metal loaded microbes using magnetic fields. Final report; Grundverfahrensentwicklung zur Abtrennung schwermetallbeladener Mikroorganismen im Magnetfeld. Abschlussbericht  

Energy Technology Data Exchange (ETDEWEB)

The research project includes the cleaning of heavy metal contamined water of the former Freiberg ore mining area. For the decontamination should be taken from the mine water isolated microorganisms as biosorbents. Under the Microorganisms are found the species Acinetobacter, Pseudomonas, Bacillus, Flavobacterium and Rhodococcus. Especially the species Bacillus and Flavobacterium were already successfully used for the heavy metal accumulation. The cultivation of the mentioned microbes from one adit of Freiberg was difficult, but successful. The production of large amounts of living biomass, which is the basis for the presupposition of the research projects aim, must be investigatet. The separation of heavy metal contamined biomass from cleaned water is possible by means of mechanical processes. Furthermore the separation by magnetic methods must be examined. (orig.) [Deutsch] Das Forschungsvorhaben beinhaltet die Reinigung schwermetallkontaminierter Grubenwaesser des ehemaligen Freiberger Erzbergbaus. Fuer die Dekontamination sollen aus Grubenwaessern isolierte Mikroorganismen als Biosorbentien verwendet werden. Dies sind Vertreter der Gattungen: Acinetobacter, Pseudomonas, Bacillus, Flavobacterium und Rhodococcus. Species der Gattungen Bacillus und Flavobacterium wurden bereits erfolgreich zur Schwermetallakkumulation eingesetzt. Die Anzucht der genannten Mikroben aus einem Freiberger Stollen war schwierig, aber erfolgreich. Die Gewinnung ausreichender Mengen lebender Biomasse, die die Voraussetzung fuer die Erreichung des Forschungszieles ist, muss noch untersucht werden. Die Abtrennung schwermetallbeladener Biomasse aus dem gereinigten Wasser ist mit bekannten mechanischen Verfahren moeglich. Weiterhin wird die Abtrennung mit magnetischen Methoden geprueft. (orig.)

Gruner, E.; Madai, E.

1993-12-31

276

MAGNET  

CERN Multimedia

The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

by B. Curé

2011-01-01

277

An electromagnetic separator  

Energy Technology Data Exchange (ETDEWEB)

An electromagnetic separator is proposed, which includes a transporter belt, a magnetic system with polar tips, which have operational facets adjoined with them, and an unloading device. In order to increase the effectiveness of the separation process through increasing the field strength of the magnetic field in the zone of separation, the operational facets of the polar tips are located at an angle to the vertical, while the facets adjoined with them are positioned parallel to the horizon and are made with sharp edges at the point of abutment. Moreover, the unloading device is made of two rectancular plates, rigidly connected to each other by cross members.

Tkhonov, A.A.; Gubarevich, V.N.; Kravchenko, N.D.; Panamarev, V.A.; Vinokurov, G.G.; Zelenchuk, V.A.

1980-03-28

278

MAGNET  

CERN Multimedia

Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

Benoit Curé

2010-01-01

279

MAGNET  

CERN Multimedia

  Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

B. Curé

2012-01-01

280

MAGNET  

CERN Multimedia

  The magnet was energised at the beginning of March 2012 at a low current to check all the MSS safety chains. Then the magnet was ramped up to 3.8 T on 6 March 2012. Unfortunately two days later an unintentional switch OFF of the power converter caused a slow dump. This was due to a misunderstanding of the CCC (CERN Control Centre) concerning the procedure to apply for the CMS converter control according to the beam-mode status at that time. Following this event, the third one since 2009, a discussion was initiated to define possible improvement, not only on software and procedures in the CCC, but also to evaluate the possibility to upgrade the CMS hardware to prevent such discharge from occurring because of incorrect procedure implementations. The magnet operation itself was smooth, and no power cuts took place. As a result, the number of magnetic cycles was reduced to the minimum, with only two full magnetic cycles from 0 T to 3.8 T. Nevertheless the magnet suffered four stops of the cryogeni...

B. Curé

2012-01-01

 
 
 
 
281

Rigorous Dyson equation and quasi-separable T-scattering operator technique for study of magnetic response from ordered and disordered non-magnetic particles' ensembles at electromagnetic wave multiple scattering  

Science.gov (United States)

An exact Dyson equation for averaged over electromagnetic crystal unit cell propagating total wave electric field is derived, with supposing the incident wave electric field to have the Floquet property. The mass operator related to periodic structure effective tensor dielectric permittivity is written as double Fourier transform from electric field Tscattering operator of the structure unit cell. The Lippmann-Swinger equation for the unit cell T-scattering operator, written in terms of the unit cell T-scattering operator in free space and the electric field lattice tensor Green function interaction part, is resolved by quasi-separable method. This recently presented quasi-separable approach to unit cell Tscattering operator enables one to consider unit cell containing several particles, with coupling between them directly inside the cell as well as through the structure via above lattice Green function interaction part. The obtained quasiseparable unit cell T-scattering operator is applied to study double diamagnetic-paramagnetic narrow peak in artificial periodical material with unit cell including the coupled plasmonic particles. Actually this magnetic phenomenon is appeared as combination result of space-group resonance between two small dielectric spheres and plasmonic resonance inside a single sphere. Studying the magnetic response of disordered media, we use Dyson self-consistent exact equation for ensemble averaged wave electric field inside dense discrete random media, with a random mass operator having been put under averaging sign. The random mass operator was written in terms of particles' correlations functions of all orders and particles' clusters' T-scattering operators. We discuss comparison between the unit cell T-scattering operator of periodic discrete structure and a cluster T-scattering operator of random discrete structure and consider the above double diamagnetic-paramagnetic peak also in random discrete structure of coupled small plasmonic dielectric spherical particles.

Barabanenkov, Yurii N.; Barabanenkov, Mikhail Y.

2013-05-01

282

Magnetic separation of human podocalyxin-like protein 1 (hPCLP1)-positive cells from peripheral blood and umbilical cord blood using anti-hPCLP1 monoclonal antibody and protein A expressed on bacterial magnetic particles.  

UK PubMed Central (United Kingdom)

Hemangioblasts are common progenitors of hematopoietic and angiogenic cells, which have been demonstrated in the mouse to possess a unique cell surface marker, podocalyxin-like protein 1 (PCLP1) (Hara, T. et al., Immunity, 11: 567-578. 1999). In this study, we prepared a novel monoclonal antibody against human PCLP1 (hPCLP1) and attempted to isolate human hematopoietic progenitor cells from umbilical cord blood and peripheral blood using nano-sized bacterial magnetic particles (BacMPs) coupled with the anti-hPCLP1 antibody. Flow cytometric analysis demonstrated that the purity of separated hPCLP1-positive cells from peripheral blood was approximately 95% whereas peripheral blood mononuclear cells contained only 0.1% PCLP1+ cells. Umbilical cord blood was demonstrated to be a better source for PCLP1+ cells than peripheral blood. These results suggest that the separation of human PCLP1+ cells using BacMPs with anti-hPCLP1 were extremely effective and may be useful as a means to prepare human hematopoietic progenitor cells.

Kuhara M; Yoshino T; Shiokawa M; Okabe T; Mizoguchi S; Yabuhara A; Takeyama H; Matsunaga T

2009-01-01

283

MAGNET  

CERN Document Server

  The magnet was operated without any problem until the end of the LHC run in February 2013, apart from a CERN-wide power glitch on 10 January 2013 that affected the CMS refrigerator, causing a ramp down to 2 T in order to reconnect the coldbox. Another CERN-wide power glitch on 15 January 2013 didn’t affect the magnet subsystems, the cryoplant or the power converter. At the end of the magnet run, the reconnection of the coldbox at 2.5 T was tested. The process will be updated, in particular the parameters of some PID valve controllers. The helium flow of the current leads was reduced but only for a few seconds. The exercise will be repeated with the revised parameters to validate the automatic reconnection process of the coldbox. During LS1, the water-cooling services will be reduced and many interventions are planned on the electrical services. Therefore, the magnet cryogenics and subsystems will be stopped for several months, and the magnet cannot be kept cold. In order to avoid unc...

B. Curé

2013-01-01

284

MAGNET  

CERN Multimedia

The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

Benoit Curé

2010-01-01

285

MAGNET  

CERN Multimedia

  The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

B. Curé

2012-01-01

286

MAGNET  

CERN Document Server

The CMS magnet has been running steadily and smoothly since the summer, with no detected flaw. The magnet instrumentation is entirely operational and all the parameters are at their nominal values. Three power cuts on the electrical network affected the magnet run in the past five months, with no impact on the data-taking as the accelerator was also affected at the same time. On 22nd June, a thunderstorm caused a power glitch on the service electrical network. The primary water cooling at Point 5 was stopped. Despite a quick restart of the water cooling, the inlet temperature of the demineralised water on the busbar cooling circuit increased by 5 °C, up to 23.3 °C. It was kept below the threshold of 27 °C by switching off other cooling circuits to avoid the trigger of a slow dump of the magnet. The cold box of the cryogenics also stopped. Part of the spare liquid helium volume was used to maintain the cooling of the magnet at 4.5 K. The operators of the cryogenics quickly restarted ...

B. Curé

2011-01-01

287

Novel ion imprinted polymer magnetic mesoporous silica nano-particles for selective separation and determination of lead ions in food samples.  

Science.gov (United States)

A novel Pb(II) ion imprinted polymer coated on magnetic mesoporous silica was synthesised and characterised by scanning electron microscopy (SEM), thermal gravimetric/differential thermal analysis (TG/DTA), elemental analysis (CHN) and low angle X-ray powder diffraction (XRD). The application of this sorbent was investigated in preconcentration and determination of low concentrations of lead ions. Through this study, various effective factors on determination, such as pH of the sample solution, eluent including type, concentration and volume, adsorption and desorption time which are effective on the method efficiency, were appraised. In order to investigate the selectivity of this sorbent toward Pb(II) ions, the effect of variety of ions on preconcentration and recovery of Pb(II) ions were also investigated. The limit of detection (LOD) was found to be lower than 1.3?gL(-1) and the recovery and relative standard deviation (RSD%) of the method were higher than 97.3% and lower than 2.9%, respectively. The application of this sorbent was investigated in separation and determination of lead-contaminated food with concentration below the detection limit of flame atomic adsorption spectroscopy. Validation of the presented method was performed by analysing several standard reference materials with certified lead concentrations. PMID:23993507

Aboufazeli, Forouzan; Lotfi Zadeh Zhad, Hamid Reza; Sadeghi, Omid; Karimi, Mohammad; Najafi, Ezzatollah

2013-06-22

288

MAGNET  

CERN Multimedia

The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

B. Curé

2011-01-01

289

ORTHODONTIC SEPARATORS  

UK PubMed Central (United Kingdom)

An orthodontic separator (10, 20, 30, 100), said separator (10, 20, 30, 100) dimensioned such that it can be inserted between adjacent teeth, said separator being characterized in that when inserted between adjacent teeth in the oral environment, it exhibits an increase in compressive force, wherein the separator exerts sufficient force on the adjacent teeth to push the teeth apart.

HANSEN James D.; TZOU Tsi-Zong

290

Orthodontic separators  

UK PubMed Central (United Kingdom)

An orthodontic separator, said separator dimensioned such that it can be inserted between adjacent teeth, said separator being characterized in that when inserted between adjacent teeth in the oral environment, it exhibits an increase in compressive force, wherein the separator exerts sufficient force on the adjacent teeth to push the teeth apart.

HANSEN JAMES D; TZOU TSI-ZONG

291

Electromagnetic ion separator  

CERN Multimedia

In this paper we study the dynamics of charged particles interacting with a space homogeneous but time oscillating magnetic field of arbitrary amplitude and frequency. We analyze the stability of the particles orbits as functions of the magnetic field parameters and their masses. Based on the fact for a given magnitude field, the particles trajectories may become unstable depending on their masses, that we propose this system as an isotopic separator. (Author)

Calvo, M

2002-01-01

292

Spin-reorientation transition of Ni/Cu(100) and CO/Ni/Cu(100): Separation of the surface and bulk components of the x-ray magnetic circular dichroism spectrum  

International Nuclear Information System (INIS)

[en] The spin-reorientation transition of Ni/Cu(100) and CO/Ni/Cu(100) films was investigated with the depth-resolved x-ray magnetic circular dichroism (XMCD) technique. The XMCD spectra from the surface and inner layers were separately extracted. As for the bare Ni films, the in-plane orbital magnetic moment in the surface layer is significantly enhanced. In contrast, the inner layers exhibit larger perpendicular orbital magnetic moment than the in-plane one. Upon CO adsorption, the surface magnetization is drastically reduced, while the inner layers are unaffected. These results directly explain the spin-reorientation transition in Ni/Cu(100) and CO/Ni/Cu(100)

2005-06-01

293

Vertical separation for TCF  

International Nuclear Information System (INIS)

The authors studied an insertion for electrostatic separation of the electron and positron beams with the aims of: increasing luminosity by decreasing the minimum bunch spacing, matching the vertical dispersion function (not done in the Jowett lattice). The authors looked at three possibilities for the start of the insertion: a quadrupole doublet followed by the electrostatic separator (Jowett), a quadrupole doublet with the electrostatic separator between the two quadrupoles (Kamada), a separator followed by a quadrupole doublet. The third possibility was immediately discharged. Although possible for a B-factor with magnetic separation it is impractical for use with electrostatic separation because of the length and cross section of separator required. The Kamada scheme looked promising for getting very short inter-bunch spacing, but suffered from the disadvantage of requiring a very large ratio of beta functions at the Interaction Point (IP) (?x*/?y* = 100). (They would rather have a ?* ratio closer to 20 to 1). They decided to persue the doublet scheme to see whether it could match the performance of Kamada insertion. They assumed superconducting magnets could be used for the insertion quadrupoles, and they used as strong an electrostatic field for the separator as Kamada.

1989-01-01

294

MAGNET  

CERN Multimedia

The magnet worked very well at 3.8 T as expected, despite a technical issue that manifested twice in the cryogenics since June. All the other magnet sub-systems worked without flaw. The issue in the cryogenics was with the cold box: it could be observed that the cold box was getting progressively blocked, due to some residual humidity and air accumulating in the first thermal exchanger and in the adsorber at 65 K. This was later confirmed by the analysis during the regeneration phases. An increase in the temperature difference between the helium inlet and outlet across the heat exchanger and a pressure drop increase on the filter of the adsorber were observed. The consequence was a reduction of the helium flow, first compensated by the automatic opening of the regulation valves. But once they were fully opened, the flow and refrigeration power reduced as a consequence. In such a situation, the liquid helium level in the helium Dewar decreased, eventually causing a ramp down of the magnet current and a field...

Benoit Curé

2010-01-01

295

MAGNET  

CERN Multimedia

MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

B. Curé

296

MAGNET  

CERN Document Server

The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

Benoit Curé.

297

MAGNET  

CERN Document Server

The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

B. Curé

2013-01-01

298

Electrostatic separator and mass separation  

International Nuclear Information System (INIS)

[en] Present performance of KEK electrostatic separator (Mark I) and the results of mass separation test using this separator and described. Maximum voltage of 900 kV was obtained with the 3 m separator and of 800 kV with the 9 m separator across the electrode spacing of 10 cm. Mass separation test using the 9 m separator was attempted at the bubble chamber beam Kl, and mass separation between pion and proton was achieved at the momentum of 3.5 GeV/c and 2 GeV/c. Separation ratio of -- 3.6 between pion and proton was obtained. The relative kaon yields were enriched from -- 1/200 to -- 1/15 at the mass slit when the separator was tuned at the momentum of 3.5 GeV/c. (auth.)

1978-01-01

299

Magnet technology from {mu}l up to m{sup 3} - application examples of magnetic separator developed at the ITC-WGT; Magnettechnologie fuer {mu}l bis m{sup 3} - Anwendungsbeispiele von Magnetseparatorentwicklungen aus dem ITC-WGT  

Energy Technology Data Exchange (ETDEWEB)

Magnet technology offers the unique property of manipulating and selectively separating magnetic particles down to the and sometimes even below micrometer size. On the one hand, particles of this kind are encountered in large volumes, e.g. in the steel, car or mineral industry, but also in the chemical industry, for example in the form of suspended catalysts. On the other hand, magnetic microparticles play an important role in many bioanalytical and diagnostic assays, where they are often suspended in volumes of a few {mu}l only. Despite the large differences in volume, the basic principles of magnetic separation are common to all these applications and widely explored by several technology transfer projects. (orig.)

Franzreb, M. [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. fuer Technische Chemie

2007-07-01

300

Double metal-insulator transitions and MR in La(0.67)Ca(0.33)Mn(1-x)Ru(x)O(3) (xmagnetic phase separation  

CERN Document Server

This paper is in continuation of our previous work on the structural, electrical and magnetic properties of Ru doped La(0.67)Ca(0.33)MnO(3) compounds (Ref.: L.Seetha Lakshmi et.al, J. Magn. Magn. Mater. 257, 195 (2003)). Here we report the results of magnetotransport measurements on La(0.67)Ca(0.33)Mn(1-x)Ru(x)O(3) (0magnetic phase separation.

Lakshmi, L S; Natarajan, D V; Rawat, R; Chandra, S; Sastry, V S; Radhakrishnan, T S; Rawat, Rajeev; Chandra, Sharat

2003-01-01

 
 
 
 
301

MAGNET  

CERN Document Server

The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

Benoit Curé

302

MAGNET  

CERN Document Server

During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

B. Curé

303

Orthodontic separators  

UK PubMed Central (United Kingdom)

An orthodontic separator, dimensioned such that it can be inserted between adjacent teeth. The separator is characterized in that it exhibits an increase in compressive force after insertion between adjacent teeth in the oral environment. The separator, after insertion, exerts sufficient force on the adjacent teeth to push the teeth apart.

HANSEN JAMES D; TZOU TSI-ZONG

304

Sulfur and mineral compounds removal from coal pulp using a pilot dry magnetic separator; Enlevement du soufre et de matieres minerales de pulpe de charbon par un separateur magnetique pilote a sec  

Energy Technology Data Exchange (ETDEWEB)

Coal washing tests have been performed with a high intensity magnetic separator for the removal of sulfur and inorganic compounds. Using a coal with initially 12.7% of ash and 2.82% of sulfur, the optimized process allows to obtain a washed coal with 8.1% of ash, 1.56% of sulfur and a fuel recovery of 50%. Abstract only. (J.S.)

Dincer, H.; Atesok, G.; Dogan, M.Z.; Girgin, S.; Boylu, F.; Yuksel, O. [Universite Technique d' Istanboul (Turkey)

2001-03-01

305

Isotopic separation  

International Nuclear Information System (INIS)

Apparatus for the separation-nozzle enrichment of a gas mixture includes: a cylindrical housing with a horizontal axis; a multistage radial compressor along the axis of the housing; separating-nozzle units forming separating stages associated with respective stages of the compressor and disposed around the compressor; coolers associated with each compressor and each separating nozzle stage disposed coaxially around the compressor; means for introducing the gas mixture into the housing; and means for recovering the isotope enriched gas mixture. The separating-nozzle units are connected in a cascade for progressive isotope enrichment of a gas mixture

1979-01-20

306

A comparative study of the magnetic properties and phase separation behavior of the rare earth cobaltates, Ln 0.5Sr0.5CoO3 (Ln=rare earth)  

International Nuclear Information System (INIS)

A comparative study of the magnetic properties of a few members of the Ln 0.5Sr0.5CoO3 family with different radii of the A-site cations, A >, in the range 1.19-1.40 A has been carried out. The apparent T c (where the magnetization undergoes an abrupt increase) decreases markedly with A > as well as the size-disorder arising from the mismatch in the size of the A-site cations. The value of the magnetization at low temperatures decreases markedly with decrease in A > or increase in size-disorder, suggesting that the relative proportion of the ferromagnetic (FM) species decreases relative to that of the paramagnetic (PM) species. Such a variation of the FM/PM ratio with composition and temperature is evidenced from the Moessbauer spectra of La0.5Sr0.5CoO3 as well. The variation of the FM/PM ratio with A > and size-disorder, as well as a local-probe study using 59Co Nuclear magnetic resonance spectroscopy suggest that electronic phase separation is an inherent feature of the Ln 0.5Sr0.5CoO3 type cobaltates, with the nature of the different magnetic species in the phase-separated system varying with A > and size disorder. - Graphical abstract: Variation of (a) T c and (b) FC magnetization at 1000 Oe with A > at 120 K in Ln 0.5Sr0.5CoO3 and Dy0.34Nd0.16Sr0.40Ca0.10CoO3.

2007-01-01

307

The impact of quantum dots magnetization on spin separation and spin current in a multiple quantum-dot ring in the presence of Rashba spin-orbit coupling  

Science.gov (United States)

The influence of quantum dot magnetization on electronic spin-dependent transport is investigated through a triple-quantum-dot ring structure in which one of the quantum dots is non-magnetic subjected to the Rashba spin-orbit interaction and the two other ones possess magnetic structure. Evaluated results, based on single particle Green's function formalism, indicate that the presence of magnetic moment on the quantum dots leads to additional spin-dependent phase factor which affects electronic transport through the system. For both antiferromagnetic and ferromagnetic quantum dots, the system can operate as a spin-splitter but differently; by tuning Rashba spin-orbit strength and in the presence of magnetic flux, respectively. Besides, in the absence of one of the outgoing leads, spin current in the output is calculated and demonstrated that magnetization of quantum dots leads to spin current even in the absence of Rashba spin-orbit effect. Moreover, it is shown that in the presence of Rashba spin orbit interaction, magnetic quantum dots, and magnetic flux, the two terminal system produces a completely tunable spin current.

Faizabadi, Edris; Eslami, Leila

2012-06-01

308

MAGNET  

CERN Document Server

The first phase of the commissioning ended in August by a triggered fast dump at 3T. All parameters were nominal, and the temperature recovery down to 4.5K was carried out in two days by the cryogenics. In September, series of ramps were achieved up to 3 and finally 3.8T, while checking thoroughly the detectors in the forward region, measuring any movement of and around the HF. After the incident of the LHC accelerator on September 19th, corrective actions could be undertaken in the forward region. When all these displacements were fully characterized and repetitive, with no sign of increments in displacement at each field ramp, it was possible to start the CRAFT, Cosmic Run at Four Tesla (which was in fact at 3.8T). The magnet was ramped up to 18.16kA and the 3 week run went smoothly, with only 4 interruptions: due to the VIP visits on 21st October during the LHC inauguration day; a water leak on the cooling demineralized water circuit, about 1 l/min, that triggered a stop of the cooling pumps, and resulte...

B. Curé

309

MAGNET  

CERN Document Server

The cooling down to the nominal temperature of 4.5 K was achieved at the beginning of August, in conjunction with the completion of the installation work of the connection between the power lines and the coil current leads. The temperature gradient on the first exchanger of the cold box is now kept within the nominal range. A leak of lubricant on a gasket of the helium compressor station installed at the surface was observed and several corrective actions were necessary to bring the situation back to normal. The compressor had to be refilled with lubricant and a regeneration of the filters and adsorbers was necessary. The coil cool down was resumed successfully, and the cryogenics is running since then with all parameters being nominal. Preliminary tests of the 20kA coil power supply were done earlier at full current through the discharge lines into the dump resistors, and with the powering busbars from USC5 to UXC5 without the magnet connected. On Monday evening August 25th, at 8pm, the final commissionin...

Benoit Curé

310

Optics of mass separator I  

Energy Technology Data Exchange (ETDEWEB)

The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear and angular magnifications, and the dispersion. The possibility of converting the magnet into a tunable unit by means of current-carrying elements in the gap is demonstrated. The feasibility of correction coils constructed from printed circuit board is shown.

Balestrini, S.J.

1981-07-01

311

Optics of mass separator I  

International Nuclear Information System (INIS)

[en] The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear and angular magnifications, and the dispersion. The possibility of converting the magnet into a tunable unit by means of current-carrying elements in the gap is demonstrated. The feasibility of correction coils constructed from printed circuit board is shown

1981-01-01

312

Analytical model of batch magnetophoretic separation  

Science.gov (United States)

Magnetophoresis (the motion of magnetic particles driven by the nonuniform magnetic field), that for a long time has been used for extracting magnetically susceptible objects in diverse industries, now attracts interest to develop more sophisticated microfluidic and batch techniques for separation and manipulation of biological particles, and magnetically assisted absorption and catalysis in organic chemistry, biochemistry, and petrochemistry. A deficiency of magnetic separation science is the lack of simple analytical models imitating real processes of magnetic separation. We have studied the motion of superparamagnetic (generally, soft magnetic) particles in liquid in the three-dimensional field of the diametrically polarized permanent cylindrical magnet; this geometry is basically representative of the batch separation mode. In the limit of the infinite-length magnet, we found the particle magnetophoresis proceeds independently of the magnet polarization direction, following the simple analytical relation incorporating all the relevant physical and geometrical parameters of the particle-magnet system. In experiments with a finite-length magnet we have shown applicability of the developed theory as to analyze the performance of the real batch separation systems in the noncooperative mode, and finally, we have presented an example of such analysis for the case of immunomagnetic cell separation and developed a criterion of the model limitation imposed by the magnetic aggregation of particles.

Kashevsky, S. B.; Kashevsky, B. E.

2013-06-01

313

Analytical model of batch magnetophoretic separation.  

UK PubMed Central (United Kingdom)

Magnetophoresis (the motion of magnetic particles driven by the nonuniform magnetic field), that for a long time has been used for extracting magnetically susceptible objects in diverse industries, now attracts interest to develop more sophisticated microfluidic and batch techniques for separation and manipulation of biological particles, and magnetically assisted absorption and catalysis in organic chemistry, biochemistry, and petrochemistry. A deficiency of magnetic separation science is the lack of simple analytical models imitating real processes of magnetic separation. We have studied the motion of superparamagnetic (generally, soft magnetic) particles in liquid in the three-dimensional field of the diametrically polarized permanent cylindrical magnet; this geometry is basically representative of the batch separation mode. In the limit of the infinite-length magnet, we found the particle magnetophoresis proceeds independently of the magnet polarization direction, following the simple analytical relation incorporating all the relevant physical and geometrical parameters of the particle-magnet system. In experiments with a finite-length magnet we have shown applicability of the developed theory as to analyze the performance of the real batch separation systems in the noncooperative mode, and finally, we have presented an example of such analysis for the case of immunomagnetic cell separation and developed a criterion of the model limitation imposed by the magnetic aggregation of particles.

Kashevsky SB; Kashevsky BE

2013-06-01

314

Novel magnetic flux penetration in overdoped La2-xSrxCuO4 single crystals: macroscopic phase separation in a heavily overdoped regime  

International Nuclear Information System (INIS)

Superconducting diamagnetic properties and magnetic flux penetration have been comparatively investigated on two La2-xSrxCuO4 single crystals: one underdoped (x=0.092) and the other overdoped (x = 0.24). Both samples have only a single transition when the external field is low. While when a relatively high external field is applied, a large distinction between these two samples is observed: there is only one transition for the underdoped sample, but an unexpected second transition appears for the overdoped sample. Further investigation on the overdoped sample shows that it has a novel property of magnetic flux penetration, which is characterized by the vanishing of the usual central peak near zero field on the magnetization hysteresis loops. This easy penetration of magnetic flux can be understood in the picture of percolative superconductivity due to the inhomogeneous electronic state in a heavily overdoped regime. (author)

2002-01-01

315

Field dependence of the electronic phase separation in Pr0.67Ca0.33MnO3 by small angle magnetic neutron scattering  

CERN Document Server

We have studied by small angle neutron scattering the evolution induced by the application of magnetic field of the coexistence of ferromagnetism (F) and antiferromagnetism (AF) in a crystal of Pr$_{0.67}$Ca$_{0.33}$MnO$_3$. The results are compared to magnetic measurements which provide the evolution of the ferromagnetic fraction. These results show that the growth of the ferromagnetic phase corresponds to an increase of the thickness of the ferromagnetic ''cabbage'' sheets.

Mercone, S; Martin, C; Simon, C; Saurel, D; Brulet, A; Mercone, Silvana; Hardy, Vincent; Martin, Christine; Simon, Charles; Saurel, Damien; Brulet, Annie

2003-01-01

316

CENTRIFUGAL SEPARATOR  

UK PubMed Central (United Kingdom)

Provided is a centrifugal separator that can perform separation of mixed fluids ranging in quantity from a very small value to a large value by simple operation. This centrifugal separator is characterized in that the separator includes a channel (20) for making mixed fluids (MF) heterogeneous while passing the mixed fluids (MF) therethrough by a centrifugal force about the axis of rotation, a supply port (30) for supplying the mixed fluids (MF) into the channel (20), a discharge channel (41) for discharging the fluid (HF) having a large specific gravity among the mixed fluids (MF) from the channel (20), and a discharge channel (42) for discharging the fluid (LF) having a small specific gravity among the mixede fluids (MF).

FUNAMOTO TAISUKE; HOSAKA MAKOTO; KONISHI SATOSHI; YOSHIDA HIROSHI

317

Isotopic separation  

International Nuclear Information System (INIS)

Isotopic species in an isotopic mixture including a first species having a first isotope and a second species having a second isotope are separated by selectively exciting the first species in preference to the second species and then reacting the selectively excited first species with an additional preselected radiation, an electron or another chemical species so as to form a product having a mass different from the original species and separating the product from the balance of the mixture in a centrifugal separating device such as centrifuge or aerodynamic nozzle. In the centrifuge the isotopic mixture is passed into a rotor where it is irradiated through a window. Heavier and lighter components can be withdrawn. The irradiated mixture experiences a large centrifugal force and is separated in a deflection area into lighter and heavier components. (UK)

1979-01-01

318

Product separator  

International Nuclear Information System (INIS)

A description is given of a secondary light sensitive photoelectric product separator for use with a primary product separator that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate separation is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to separate from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted, nothing moves on the second separator. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected separated concentrate is recovered at a maximum rate regardless of variations in the flow stream or other conditions present.

1976-01-01

319

Magnetically separable ?-Fe2O3-SiO2-Ce-doped TiO2 core–shell nanocomposites: Fabrication and visible-light-driven photocatalytic activity  

International Nuclear Information System (INIS)

Novel visible-light-induced ?-Fe2O3-SiO2-Ce-doped-TiO2 core–shell nanocomposite photocatalysts capable of magnetic separation have been synthesized by a facile sol–gel and after-annealing process. The as-obtained core–shell nanocomposite is composed of a central ?-Fe2O3 core with a strong response to external fields, an interlayer of SiO2, and an outer layer of Ce-doped TiO2 nanocrystals. UV–vis spectra analysis indicates that Ce doping in the compound results in a red-shift of the absorption edge, thus offering increased visible light absorption. We show that such a ?-Fe2O3-SiO2-Ce-doped-TiO2 core–shell nanocomposite with appreciated Ce doping amount exhibits much higher visible-light photocatalytic activity than bare TiO2 and undoped ?-Fe2O3-SiO2-TiO2 core–shell nanocomposite toward the degradation of rhodamine B (RhB). Moreover, the ?-Fe2O3-SiO2-Ce-doped-TiO2 core–shell nanocomposite photocatalysts could be easily separated and reused from the treated water under application of an external magnetic field. - Graphical abstract: Novel ?-Fe2O3-SiO2-Ce-doped-TiO2 core/shell nanocomposite photocatalysts with enhanced photocatalytic activity and fast magnetic separability were prepared. Highlights: ? Novel ?-Fe2O3-SiO2-Ce-doped TiO2 core/shell composite photocatalysts were prepared. ? The resulting core/shell composite show high visible light photocatalytic activity. ? The nanocomposite photocatalysts can be easily recycled with excellent durability.

2012-01-01

320

N, N'-dimethyl-N, N'-dibutyl tetradecyl malonamide impregnated magnetic particles for the extraction and separation of radionuclides from nuclear waste streams  

International Nuclear Information System (INIS)

N, N'-dimethyl-N, N'-dibutyl tetradecyl malonamide (DMDBTDMA) coated magnetic particles are being evaluated for the possible application in the partitioning of actinides, lanthanides and fission products from pure nitric acid solutions as well as from simulated pressurized heavy water reactor-high level waste (PHWR-SHLW). Uptake profiles of various metal ions, such as Pu(IV), U(VI), Am(III), Eu(III), Sr(II) and Cs(I) were obtained as a function of time and nitric acid concentration by batch studies using DMDBTDMA coated magnetic particles. The order of uptake follows the order Pu(IV) > U(VI) > Am(III) > Eu(III) > Sr(II) ? Cs(I) in both nitric acid and SHLW. The uptake of various trivalent lanthanides was also investigated as a function of nitric acid concentration and found the uptake order as Pr(III) > La(III) > Eu(III) > Tb(III) > Ho(III) > Er(III) > Yb(III) > Lu(III). The sorption capacity of the DMDBTDMA coated magnetic particles with respect to U(VI) and Eu(III) was determined, along with the sorption isotherms to simulate multiple contacts. The maximum sorption capacity of DMDBTDMA coated magnetic particles was found to be 1.58 mmol/g and 0.36 mmol/g for U(VI) and Eu(III), respectively. The adsorption models of Langmuir and Freundlich were fitted to the experimental data and best correlations were obtained for both the models. The Langmuir model predicts a loading capacity of 1.61 mmol/g and 0.37 mmol/g for U(VI) and Eu(III), respectively, which is close to the experimental values. The stability and recycling capacity of the DMDBTDMA coated magnetic particles was also assessed. (orig.)

2006-01-01

 
 
 
 
321

Centrifugal separator  

International Nuclear Information System (INIS)

Centrifuges having a cylindrical rotary member are limited in their efficiency owing to stresses generated by high peripheral speeds; that is, in order to maintain reliability, speeds are usually restricted to approximately 250 m/sec. Furthermore, in a continuous separation process, the flow of gases within the cylindrical member is not fully understood, raising doubts about the value of centrifuges of this type. The present invention discloses a novel centrifuge featuring a disk-like rotary member in which centrifugally induced stress is comparatively small, a rotary vessel which, through a series of repetitive operations effected by change over valves, seals a gas for a fixed interval therein and then allows the thus separated light and heavy components to be separately and successively extracted therefrom. Furthermore, since stress results in an increase in the outer diameter, it is possible to reduce the rotational frequency to obtain an equivalent peripheral speed. Therefore, unlike the continuous separation system of the former art, the intermittent system of the present invention allows the separation operation to be explicitly implimented and greatly simplifies the overall apparatus. (Owens, K.J.).

1970-01-01

322

Westcoal separator  

Energy Technology Data Exchange (ETDEWEB)

The objective is to produce a spiral configuration to give a low density cut point required for cleaning western Canadian coals to meet marketing specifications. The findings of a feasibility study that includes field trials and the conceptual design of a spiral device known as the Westcoal Separator are presented. The Westcoal Separator potentially has three advantages over current spiral designs, namely, a low cut point from the reconfiguration of the hydraulic profile of the spiral design; increased starts per unit from the current maximum of three; and integration of feed distributor into the unit. Construction of a prototype and application of a patent for the Westcoal Separator are recommended. 35 refs., 25 figs., 21 tabs.

Butcher, S.G.

1989-05-01

323

SEPARATION DEVICE  

UK PubMed Central (United Kingdom)

A separation device for separating a wanted end product from a liquid sample comprises a container (2) having a first end (5) and a second end (7), the first end having a central orifice (6), a plunger (3) slideably disposed in the container (2) to define a variable liquid receiving chamber between the plunger (3) and the orifice (6), and a permeable partition member (9) mounted to the plunger (3) in a spaced relationship thereto to define a compartment (12) between the partition member (9) and the plunger (3) for receiving liquid density gradient medium (13), wherein liquid may be drawn into the container (2) and expelled therefrom, respectively, through the orifice (6) by movement of the plunger (3) relative to the container (2). A method for separating a wanted end product from a liquid sample is also disclosed.

FROMAN GUNNAR; OSTLIN HENRIK

324

Isotope separation  

International Nuclear Information System (INIS)

A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated

1978-01-01

325

Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions  

International Nuclear Information System (INIS)

[en] 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.

2009-01-01

326

Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions  

Energy Technology Data Exchange (ETDEWEB)

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 [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic)], E-mail: rittich@sci.muni.cz; Spanova, Alena [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Salek, Petr [Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Nemcova, Petra [Masaryk University, Faculty of Science, Institute of Experimental Biology, Tvrdeho 14, CZ-611 37 Brno (Czech Republic); Trachtova, Stepanka [Brno University of Technology, Faculty of Chemistry, Institute of Food Science and Biotechnology, Purkynova 464/118, CZ-612 00 Brno (Czech Republic); Horak, Daniel [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, CZ-162 06 Prague (Czech Republic)

2009-05-15

327

Influence of the phase separation effect on low-field magnetic properties of La1-xBaxMnO3  

International Nuclear Information System (INIS)

Magnetic susceptibility, ?(T), is investigated in ceramic La1-xBaxMnO3 (LBMO) with x=0.02-0.25 in the range of fields B=10-80G and temperatures T=5-310K. All samples exhibit a paramagnetic (PM) to ferromagnetic (FM) transition with TC increasing with x from 177K (x=0.02) to 295K (x=0.25) and magnetic irreversibility decreasing below TC with increasing x. In the PM phase an interval of the Curie-Weiss behavior of ?(T) with an effective Bohr magneton number, peff?30-40, is observed above T1?260-290K. Below T1 and down to Tcr?190-220K the susceptibility follows the scaling law ?-1(T)-?-1(TC)?(T/TC-1)? with ?=?1?1.4 corresponding to a three-dimensional (3D) Heisenberg spin system. Below Tcr, ?(T) obeys the same scaling law as for T>Tcr, but with another value of ?=?2?1.7-1.8, characteristic of a 3D percolation system. The temperature dependence of the susceptibility observed in the PM phase is explained by small FM particles embedded in the host LBMO matrix above T1. The size of these particles increases between T1 and Tcr up to nanometer scale, forming critical percolation clusters below Tcr. The magnetic irreversibility is connected to a mixed, FM and cluster-glass, phase.

2005-01-01

328

Centrifugal separator  

International Nuclear Information System (INIS)

In a centrifugal separator of the type in which a housing is constructed about a rotatable vertical cylinder supplied from its center with a gas mixture which is separated and then removed from the upper and lower ends thereof, an improvement allowing a more compact design comprising an axial bearing and axial bearing-sealing means provided, respectively, at the upper and lower ends of the housing to thereby support the ends of a rotary shaft which is inserted through the rotatable cylinder and equipped with a gas mixture supply passage and radially extending diffusion holes to admit the mixture into the cylinder, and a lower end cap for the rotatable cylinder so constructed as to function as a casing for an electromotor while enclosing therein a stator and a rotor surrounding the rotary shaft protruding therethrough. Actuation of the electromotor drives the rotor, the integrally fixed rotary shaft and the cylinder at the same frequency for the separation of a material such as UF6. The present construction is adapted for compactness and ease of assembly and disassembly; therefore, it is not necessary for the rotary shaft to protrude through the surrounding housing since the ''dead space'' at the bottom of the cylinder is utilized as the electromotor casing; the heat naturally arising therefrom may be applied as a heat source for increasing separation efficiency. (Owens, K.J.).

1970-01-01

329

Oil separator  

Energy Technology Data Exchange (ETDEWEB)

An oil separator is described for use at the scene of an oil spill. It features a tank divided by imperforate bulkheads into a folded, horizontal flow path, the flow path being further divided by perforate baffles through which the flow passes, the baffles having apertures selected to pass debris but also provide wave damping and evening of flow velocities.

Milgram, J.H.

1981-06-02

330

Separation fluid  

Energy Technology Data Exchange (ETDEWEB)

A composite is patented and technology for preparing a separating fluid which can be used in the drilling process for displacement of a drilling mud on a water base with the help of reverse emulsion muds and in the process of cementing wells where a drilling mud is used of the inverted emulsion type.

Ana, I.; Moise, G.; Popescu, F.; Tanasescu, M.; Vasile, J.

1982-05-29

331

Battery separator  

Energy Technology Data Exchange (ETDEWEB)

The invention disclosed relates to a novel paper is a composition for use as a separator material in electrical batteries. The paper composition 30-50%/w of glass fibers and 70-59%/w of a co-polymer of vinyl chloride and vinyl acetate.

Armstrong, W.A.; Wheat, J.A.

1980-09-09

332

Nuclear magnetic resonance and liquid chromatography-mass spectrometry combined with an incompleted separation strategy for identifying the natural products in crude extract  

Energy Technology Data Exchange (ETDEWEB)

NMR and LC-MS combined with an incompleted separation strategy were proposed to the simultaneous structure identification of natural products in crude extracts, and a novel method termed as NMR/LC-MS parallel dynamic spectroscopy (NMR/LC-MS PDS) was developed to discover the intrinsic correlation between retention time (Rt), mass/charge (m/z) and chemical shift ({delta}) data of the same constituent from mixture spectra by the co-analysis of parallelly visualized multispectroscopic datasets from LC-MS and {sup 1}H NMR. The extracted ion chromatogram (XIC) and {sup 1}H NMR signals deriving from the same individual constituent were correlated through fraction ranges and intensity changing profiles in NMR/LC-MS PDS spectrum due to the signal amplitude co-variation resulted from the concentration variation of constituents in a series of incompletely separated fractions. NMR/LC-MS PDS was applied to identify 12 constituents in an active herbal extract including flavonol glycosides, which was separated into a series of fractions by flash column chromatography. The complementary spectral information of the same individual constituent in the crude extract was discovered simultaneously from mixture spectra. Especially, two groups of co-eluted isomers were identified successfully. The results demonstrated that NMR/LC-MS PDS combined with the incompleted separation strategy achieved the similar function of on-line LC-NMR-MS analysis in off-line mode and had the potential for simplifying and accelerating the analytical routes for structure identification of constituents in herbs or their active extracts.

Dai Dongmei; He Jiuming [Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050 (China); Sun Ruixiang [Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100080 (China); Zhang Ruiping [Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050 (China); Aisa, Haji Akber [Xinjiang Technological Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011 (China); Abliz, Zeper [Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Xian Nong Tan Street, Beijing 100050 (China)], E-mail: zeper@imm.ac.cn

2009-01-26

333

Nuclear magnetic resonance and liquid chromatography-mass spectrometry combined with an incompleted separation strategy for identifying the natural products in crude extract  

International Nuclear Information System (INIS)

NMR and LC-MS combined with an incompleted separation strategy were proposed to the simultaneous structure identification of natural products in crude extracts, and a novel method termed as NMR/LC-MS parallel dynamic spectroscopy (NMR/LC-MS PDS) was developed to discover the intrinsic correlation between retention time (Rt), mass/charge (m/z) and chemical shift (?) data of the same constituent from mixture spectra by the co-analysis of parallelly visualized multispectroscopic datasets from LC-MS and 1H NMR. The extracted ion chromatogram (XIC) and 1H NMR signals deriving from the same individual constituent were correlated through fraction ranges and intensity changing profiles in NMR/LC-MS PDS spectrum due to the signal amplitude co-variation resulted from the concentration variation of constituents in a series of incompletely separated fractions. NMR/LC-MS PDS was applied to identify 12 constituents in an active herbal extract including flavonol glycosides, which was separated into a series of fractions by flash column chromatography. The complementary spectral information of the same individual constituent in the crude extract was discovered simultaneously from mixture spectra. Especially, two groups of co-eluted isomers were identified successfully. The results demonstrated that NMR/LC-MS PDS combined with the incompleted separation strategy achieved the similar function of on-line LC-NMR-MS analysis in off-line mode and had the potential for simplifying and accelerating the analytical routes for structure identification of constituents in herbs or their active extracts.

1000-01-00

334

Design and characterization of Ni2+ and Co2+ decorated Porous Magnetic Silica spheres synthesized by hydrothermal-assisted modified-Stober method for His-tagged proteins separation.  

UK PubMed Central (United Kingdom)

The complete elimination of enzymes from the reaction mixture and the possibility of its recycling for several rounds result in great benefits, allowing the reduction of the enzyme consumption and their usability in continuous processes. In this work, it is evaluated the capture of a H6-tagged green fluorescence protein (GFP-H6) on porous magnetic spheres using the Co(2+) and Ni(2+) affinity adsorption as a possible cost-effective and up-scaled alternative way for the immobilization of His-tagged proteins. For this purpose, Porous Magnetic Silica (PMS) spheres were synthesized by one-step hydrothermal-assisted modified-Stöber method. The obtained spheres have a homogenous size distribution of 400 nm diameter. The ?-Fe(2)O(3) nanoparticles are homogenously distributed in the silica matrix. The obtained PMS spheres have a saturation magnetization of about 10 emu/g. Magnetophoresis measurements show a total separation time of 16 min at 60 T/m. The obtained PMS spheres were successfully and homogenously decorated with Co(2+) and Ni(2+) and then evaluated for the capture of a GFP-H6 protein. The results were compared with the performance of the commercial beads Dynabeads® His-Tag Isolation & Pulldown.

Benelmekki M; Xuriguera E; Caparros C; Rodríguez-Carmona E; Mendoza R; Corchero JL; Lanceros-Mendez S; Martinez LM

2012-01-01

335

Design and characterization of Ni2+ and Co2+ decorated Porous Magnetic Silica spheres synthesized by hydrothermal-assisted modified-Stöber method for His-tagged proteins separation.  

Science.gov (United States)

The complete elimination of enzymes from the reaction mixture and the possibility of its recycling for several rounds result in great benefits, allowing the reduction of the enzyme consumption and their usability in continuous processes. In this work, it is evaluated the capture of a H6-tagged green fluorescence protein (GFP-H6) on porous magnetic spheres using the Co(2+) and Ni(2+) affinity adsorption as a possible cost-effective and up-scaled alternative way for the immobilization of His-tagged proteins. For this purpose, Porous Magnetic Silica (PMS) spheres were synthesized by one-step hydrothermal-assisted modified-Stöber method. The obtained spheres have a homogenous size distribution of 400 nm diameter. The ?-Fe(2)O(3) nanoparticles are homogenously distributed in the silica matrix. The obtained PMS spheres have a saturation magnetization of about 10 emu/g. Magnetophoresis measurements show a total separation time of 16 min at 60 T/m. The obtained PMS spheres were successfully and homogenously decorated with Co(2+) and Ni(2+) and then evaluated for the capture of a GFP-H6 protein. The results were compared with the performance of the commercial beads Dynabeads® His-Tag Isolation & Pulldown. PMID:21996010

Benelmekki, M; Xuriguera, E; Caparros, C; Rodríguez-Carmona, E; Mendoza, R; Corchero, J L; Lanceros-Mendez, S; Martinez, Ll M

2011-09-24

336

Influence of the phase separation effect on low-field magnetic properties of La{sub 1-x}Ba{sub x}MnO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

Magnetic susceptibility, {chi}(T), is investigated in ceramic La{sub 1-x}Ba{sub x}MnO{sub 3} (LBMO) with x=0.02-0.25 in the range of fields B=10-80G and temperatures T=5-310K. All samples exhibit a paramagnetic (PM) to ferromagnetic (FM) transition with T{sub C} increasing with x from 177K (x=0.02) to 295K (x=0.25) and magnetic irreversibility decreasing below T{sub C} with increasing x. In the PM phase an interval of the Curie-Weiss behavior of {chi}(T) with an effective Bohr magneton number, p{sub eff}{approx}30-40, is observed above T{sub 1}{approx}260-290K. Below T{sub 1} and down to T{sub cr}{approx}190-220K the susceptibility follows the scaling law {chi}{sup -1}(T)-{chi}{sup -1}(T{sub C}){approx}(T/T{sub C}-1){sup {gamma}} with {gamma}={gamma}{sub 1}{approx}1.4 corresponding to a three-dimensional (3D) Heisenberg spin system. Below T{sub cr}, {chi}(T) obeys the same scaling law as for T>T{sub cr}, but with another value of {gamma}={gamma}{sub 2}{approx}1.7-1.8, characteristic of a 3D percolation system. The temperature dependence of the susceptibility observed in the PM phase is explained by small FM particles embedded in the host LBMO matrix above T{sub 1}. The size of these particles increases between T{sub 1} and T{sub cr} up to nanometer scale, forming critical percolation clusters below T{sub cr}. The magnetic irreversibility is connected to a mixed, FM and cluster-glass, phase.

Laiho, R. [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Lisunov, K.G. [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Institute of Applied Physics, Academiei Str. 5, MD-2028 Kishinev, Moldova (Moldova, Republic of); Laehderanta, E. [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland)and Department of Physics, Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta (Finland)]. E-mail: erlah@utu.fi; Zakhvalinskii, V.S. [Wihuri Physical Laboratory, Department of Physics, University of Turku, FIN-20014 Turku (Finland); Belgorod State University, Pobeda Str. 85, 308015 Belgorod (Russian Federation); Kozhevnikov, V.L. [Institute of Solid State Chemistry, GSP 14591 Pervomaiskaia, 620219 Ekaterinburg (Russian Federation); Leonidov, I.A. [Institute of Solid State Chemistry, GSP 14591 Pervomaiskaia, 620219 Ekaterinburg (Russian Federation); Mitberg, E.B. [Institute of Solid State Chemistry, GSP 14591 Pervomaiskaia, 620219 Ekaterinburg (Russian Federation); Patrakeev, M.V. [Institute of Solid State Chemistry, GSP 14591 Pervomaiskaia, 620219 Ekaterinburg (Russian Federation)

2005-06-15

337

Separation research  

International Nuclear Information System (INIS)

The prototype chemical exchange system for enriching rare Ca isotopes was operated with total reflux. CS2 enriched to 50 percent 34S is being separated in a thermal diffusion cascade for the separation of 34S. The first part of a new series of total scattering cross section measurement for Ar--He was completed and the data tabulated. New determinations of the thermal diffusion factor for 20Ne--22Ne were in agreement with earlier results. Corrected thermal diffusion factors for Ne, Ar, Kr, and Xe are tabulated. Thermal diffusion data for Ne, Ar, Kr, and Xe are compared to the extended corresponding states theory and a method given to improve the accuracy of the calculation. The temperature dependence of the thermal diffusion factor of an equimolar mixture He--Kr and He--Xe is given for the temperature range 250 to 7250K. (U.S.).

1975-04-10

338

Gas separating  

Energy Technology Data Exchange (ETDEWEB)

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

339

Gas separating  

Energy Technology Data Exchange (ETDEWEB)

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

340

Separation system  

Energy Technology Data Exchange (ETDEWEB)

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

 
 
 
 
341

Magnetically separable Fe3O4@SiO2@TiO2-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity.  

UK PubMed Central (United Kingdom)

Major efforts in modern material chemistry are devoted to the design and fabrication of nanostructured systems with tunable physical-chemical properties for advanced catalytic applications. Here, a novel Fe3O4@SiO2@TiO2-Ag nanocomposite has been synthesized and characterized by a series of techniques including SEM, TEM, XRD, XPS as well as magnetization measurement and subsequently tested for the photocatalytic activities. The well-designed nanocomposite exhibits significantly superior activity to that of the commercial Degussa P25 thanks to the suppression of electron-hole pairs from recombination by Ag nanoparticles, and can be easily recycled by applying an external magnetic field while maintaining the catalytic activity without significant decrease even after running 10 times. The unique nanostructure makes Fe3O4@SiO2@TiO2-Ag a highly efficient, recoverable, stable, and cost-effective photocatalytic system offering broad opportunities in the field of catalyst synthesis and application.

Chi Y; Yuan Q; Li Y; Zhao L; Li N; Li X; Yan W

2013-09-01

342

Basic examination of magnetic separation method using the development (the second report) model raw material of the iron dirt removal method from the (RDS) oil feed stock for the redidual oil hydrodesulfurization; Zanyusuisokadatsuryuyo (RDS) genryoyu karano tekkyo kokumotsu jokyoho no kaihatsu (2) moderu genryo wo mochiita jikibunriho no kisoteki kento  

Energy Technology Data Exchange (ETDEWEB)

At magnetism and viscosity, the reason of affecting the model raw material in selection and magnetic separation was examined in respect of the {alpha} -Fe{sub 2}O{sub 3} - water/glycerin system in the relationship between iron dirt and resemblance in the RDS oil feed stock. Still, water/glycerin and redidual oil have the similarity on the magnetism on the viscosity in {alpha} -Fe{sub 2}O{sub 3} and iron dirt. As a result, it was proven that liquid linear velocity, wave viscosity, magnetic field strength and magnetism amount of material (it is called the matrix loading) on packing material influenced in the separation result. In addition, the kinetic equation of the possible separation of quantitatively showing experimental result was deduced. This equation is suitable for actual raw material system with the distribution in which the magnetism material is wide for magnetic susceptibility and particle size. In addition, the cleaning procedure of packing material was examined, and for the viscosity of the cleaning solvent, it was clarified that could comparatively wash and can remove most of the magnetizing thing in the short time, if the streamline speed is appropriately set. It is possible that the cleaning of the packing material is easy like this by the regeneration, and it is indicated that the cleaning relation facility can be made small in respect of the repetitive use of packing material. (translated by NEDO)

Ushio, Ken; Kamiya, Kozo

1999-09-01

343

Magnetically separable {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped TiO{sub 2} core-shell nanocomposites: Fabrication and visible-light-driven photocatalytic activity  

Energy Technology Data Exchange (ETDEWEB)

Novel visible-light-induced {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped-TiO{sub 2} core-shell nanocomposite photocatalysts capable of magnetic separation have been synthesized by a facile sol-gel and after-annealing process. The as-obtained core-shell nanocomposite is composed of a central {gamma}-Fe{sub 2}O{sub 3} core with a strong response to external fields, an interlayer of SiO{sub 2}, and an outer layer of Ce-doped TiO{sub 2} nanocrystals. UV-vis spectra analysis indicates that Ce doping in the compound results in a red-shift of the absorption edge, thus offering increased visible light absorption. We show that such a {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped-TiO{sub 2} core-shell nanocomposite with appreciated Ce doping amount exhibits much higher visible-light photocatalytic activity than bare TiO{sub 2} and undoped {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-TiO{sub 2} core-shell nanocomposite toward the degradation of rhodamine B (RhB). Moreover, the {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped-TiO{sub 2} core-shell nanocomposite photocatalysts could be easily separated and reused from the treated water under application of an external magnetic field. - Graphical abstract: Novel {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped-TiO{sub 2} core/shell nanocomposite photocatalysts with enhanced photocatalytic activity and fast magnetic separability were prepared. Highlights: Black-Right-Pointing-Pointer Novel {gamma}-Fe{sub 2}O{sub 3}-SiO{sub 2}-Ce-doped TiO{sub 2} core/shell composite photocatalysts were prepared. Black-Right-Pointing-Pointer The resulting core/shell composite show high visible light photocatalytic activity. Black-Right-Pointing-Pointer The nanocomposite photocatalysts can be easily recycled with excellent durability.

He, Minqiang, E-mail: jbmwgkc@126.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Di; Jiang, Deli; Chen, Min [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

2012-08-15

344

Separating device  

Energy Technology Data Exchange (ETDEWEB)

A separating device is proposed which contains a housing, upper adapter with cams, connected to the housing by left threading, and cam coupling. It is distinguished by the fact that in order to increase operating reliability of the device with multiple use by creation of guaranteed tension in the left threading, the coupling is springloaded, the coupling cams in the upper adapter are inclined with the possibility of sliding with left rotation of the upper adapter. The upper end of the housing which comes into contact with the upper adapter is made in the form of a cut spring.

Konrad, F.F.; Koshelev, N.N.; Panov, V.N.; Pasnichenko, G.F.

1982-01-01

345

Isotope separation  

International Nuclear Information System (INIS)

A process for separating uranium isotopes is described which includes: preparing a volatile compound U-T, in which U is a mixture of uranium isotopes and T is a chemical moiety containing at least one organic or deuterated borohydride group, and which exhibits for at least one isotopic species thereof a fundamental, overtone or combination vibrational absorption excitation energy level at a frequency between 900 and 1100 cm-1; and irradiating the compound in the vapour phase with energy emitted by a radiation source at a frequency between 900 and 1100 cm-1 (e.g. a CO2 laser). (author)

1981-01-01

346

Magnetic excitations and phase separation in the underdoped La2-xSrxCuO4 superconductor measured by resonant inelastic X-ray scattering.  

UK PubMed Central (United Kingdom)

We probe the collective magnetic modes of La2CuO4 and underdoped La2-xSrxCuO4 (LSCO) by momentum resolved resonant inelastic x-ray scattering (RIXS) at the Cu L3 edge. For the undoped antiferromagnetic sample, we show that the single magnon dispersion measured with RIXS coincides with the one determined by inelastic neutron scattering, thus demonstrating that x rays are an alternative to neutrons in this field. In the spin dynamics of LSCO, we find a branch dispersing up to approximately 400 meV coexisting with one at lower energy. The high-energy branch has never been seen before. It indicates that underdoped LSCO is in a dynamic inhomogeneous spin state.

Braicovich L; van den Brink J; Bisogni V; Sala MM; Ament LJ; Brookes NB; De Luca GM; Salluzzo M; Schmitt T; Strocov VN; Ghiringhelli G

2010-02-01

347

Oil separator  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an internal combustion engine including a cylinder head and a cover for each cylinder. The improvement in the engine consists of an oil separator having inlet and outlet ports which is mounted on the cylinder head cover to separate and trap the lubricating oils within the blowby gases and which further consists of: 1.) a case mounted on the cylinder head cover, 2.) a buffer apparatus positioned near the inlet port and within the case to intercept splashes of the lubricating oils within the cylinder head cover, 3.) an inclined porous filter of foaming metal material inclined at an angle of 15/sup 0/-90/sup 0/ with respect to a horizontal plane of the cylinder head case and positioned downstream of the buffer in a direction of flow of the blowby gases, and 4.) an oil reservoir positioned at the lower end of the filter to reserve the oils trapped by the filter, where the buffer further comprises a first buffer having a first inclined buffer secured to the case. This first buffer extends from the ceiling of the case, and a second buffer is formed on a bottom plate which is secured to a lower open portion of the case; and 5.) a second buffer positioned downstream of the filter and above the oil reservoir.

Okumura, S.

1986-02-11

348

Magnetic sensor  

International Nuclear Information System (INIS)

[en] The present invention provides a sensor capable of measuring an intensity of magnetic fields efficiently even under such a circumstance that strong magnetic fields are present in the direction perpendicular to magnetic fields to be measured under radiation, for example, in a thermonuclear device. Namely, an integrator or a hole element semiconductor is not preferable for the magnetic sensor under such a circumstance. Then, the sensor of the present invention measures the intensity of magnetic fields based on electromagnetic force or deformation by the electromagnetic force. When electric current (I) is supplied to a conductor, a force of F = I x B is generated per unit length of the conductor by an interaction with the magnetic fields. The magnetic fields can be measured with no drift by the measurement of the force (F). Since the deformation is utilized for the measurement of the electromagnetic force, the deformation amount (?) is measured and it is converted to the intensity of magnetic fields. The deformation amount is determined as: ? ? F/G. If the rigidity (G) is isotropic, the magnetic sensor has no directionality. However, conventional coil-type magnetic sensors have directionality and can separate magnetic field components. The directionality can be realized by making the rigidity (G) anisotropic. (I.S.)

1996-01-08

349

Magnetic sensor  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides a sensor capable of measuring an intensity of magnetic fields efficiently even under such a circumstance that strong magnetic fields are present in the direction perpendicular to magnetic fields to be measured under radiation, for example, in a thermonuclear device. Namely, an integrator or a hole element semiconductor is not preferable for the magnetic sensor under such a circumstance. Then, the sensor of the present invention measures the intensity of magnetic fields based on electromagnetic force or deformation by the electromagnetic force. When electric current (I) is supplied to a conductor, a force of F = I x B is generated per unit length of the conductor by an interaction with the magnetic fields. The magnetic fields can be measured with no drift by the measurement of the force (F). Since the deformation is utilized for the measurement of the electromagnetic force, the deformation amount ({delta}) is measured and it is converted to the intensity of magnetic fields. The deformation amount is determined as: {delta} {proportional_to} F/G. If the rigidity (G) is isotropic, the magnetic sensor has no directionality. However, conventional coil-type magnetic sensors have directionality and can separate magnetic field components. The directionality can be realized by making the rigidity (G) anisotropic. (I.S.)

Abe, Mitsushi; Hara, Shigemitsu

1997-07-22

350

Stem Cell Separation Technologies.  

UK PubMed Central (United Kingdom)

Stem cell therapy and translational stem cell research require large-scale supply of stem cells at high purity and viability, thus leading to the development of stem cell separation technologies. This review covers key technologies being applied to stem cell separation, and also highlights exciting new approaches in this field. First, we will cover conventional separation methods that are commercially available and have been widely adapted. These methods include Fluorescence-activated cell sorting (FACS), Magnet-activated cell sorting (MACS), pre-plating, conditioned expansion media, density gradient centrifugation, field flow fractionation (FFF), and dielectrophoresis (DEP). Next, we will introduce emerging novel methods that are currently under development. These methods include improved aqueous two-phase system, systematic evolution of ligands by exponential enrichment (SELEX), and various types of microfluidic platforms. Finally, we will discuss the challenges and directions towards future breakthroughs for stem cell isolation. Advancing stem cell separation techniques will be essential for clinical and research applications of stem cells.

Zhu B; Murthy SK

2013-02-01

351

Multi-cycle recovery of lactoferrin and lactoperoxidase from crude whey using fimbriated high-capacity magnetic cation exchangers and a novel "rotor-stator" high-gradient magnetic separator.  

UK PubMed Central (United Kingdom)

Cerium (IV) initiated "graft-from" polymerization reactions were employed to convert M-PVA magnetic particles into polyacrylic acid-fimbriated magnetic cation exchange supports displaying ultra-high binding capacity for basic target proteins. The modifications, which were performed at 25?mg and 2.5?g scales, delivered maximum binding capacities (Qmax ) for hen egg white lysozyme in excess of 320?mg?g(-1) , combined with sub-micromolar dissociation constants (0.45-0.69?µm) and "tightness of binding" values greater than 49?L?g(-1) . Two batches of polyacrylic acid-fimbriated magnetic cation exchangers were combined to form a 5?g pooled batch exhibiting Qmax values for lysozyme, lactoferrin, and lactoperoxidase of 404, 585, and 685?mg?g(-1) , respectively. These magnetic cation exchangers were subsequently employed together with a newly designed "rotor-stator" type HGMF rig, in five sequential cycles of recovery of lactoferrin and lactoperoxidase from 2?L batches of a crude sweet bovine whey feedstock. Lactoferrin purification performance was observed to remain relatively constant from one HGMF cycle to the next over the five operating cycles, with yields between 40% and 49% combined with purification and concentration factors of 37- to 46-fold and 1.3- to 1.6-fold, respectively. The far superior multi-cycle HGMF performance seen here compared to that observed in our earlier studies can be directly attributed to the combined use of improved high capacity adsorbents and superior particle resuspension afforded by the new "rotor-stator" HGMS design.

Brown GN; Müller C; Theodosiou E; Franzreb M; Thomas OR

2013-06-01

352

Multi-cycle recovery of lactoferrin and lactoperoxidase from crude whey using fimbriated high-capacity magnetic cation exchangers and a novel "rotor-stator" high-gradient magnetic separator.  

Science.gov (United States)

Cerium (IV) initiated "graft-from" polymerization reactions were employed to convert M-PVA magnetic particles into polyacrylic acid-fimbriated magnetic cation exchange supports displaying ultra-high binding capacity for basic target proteins. The modifications, which were performed at 25?mg and 2.5?g scales, delivered maximum binding capacities (Qmax ) for hen egg white lysozyme in excess of 320?mg?g(-1) , combined with sub-micromolar dissociation constants (0.45-0.69?µm) and "tightness of binding" values greater than 49?L?g(-1) . Two batches of polyacrylic acid-fimbriated magnetic cation exchangers were combined to form a 5?g pooled batch exhibiting Qmax values for lysozyme, lactoferrin, and lactoperoxidase of 404, 585, and 685?mg?g(-1) , respectively. These magnetic cation exchangers were subsequently employed together with a newly designed "rotor-stator" type HGMF rig, in five sequential cycles of recovery of lactoferrin and lactoperoxidase from 2?L batches of a crude sweet bovine whey feedstock. Lactoferrin purification performance was observed to remain relatively constant from one HGMF cycle to the next over the five operating cycles, with yields between 40% and 49% combined with purification and concentration factors of 37- to 46-fold and 1.3- to 1.6-fold, respectively. The far superior multi-cycle HGMF performance seen here compared to that observed in our earlier studies can be directly attributed to the combined use of improved high capacity adsorbents and superior particle resuspension afforded by the new "rotor-stator" HGMS design. PMID:23335282

Brown, Geoffrey N; Müller, Christine; Theodosiou, Eirini; Franzreb, Matthias; Thomas, Owen R T

2013-02-22

353

Centrifugal separator  

International Nuclear Information System (INIS)

A centrifuge for the separation or enrichment of gaseous isotopes is disclosed. A stationary shaft both ends of which are fixed to the opposing side walls of a stationary sealed vessel suspends and supports therewithin a rotary drum integrally joined to a hollow rotary shaft projecting therefrom. By means of a volute fan mounted at one end cap of the rotary drum process gases are fed into the drum through an axial passage within the stationary shaft. Mounted to the stationary shaft within the drum in the vicinity of the opposite end thereof are scoop mechanisms adapted to remove gaseous fractions from the system by feeding them through axial passages provided within the shaft. Means are provided to permit a portion of the removed gases to be employed as a lubricant for gas bearings and a sealant for shaft sealing devices. (K.J. Owens).

1970-01-01

354

Oil separator  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a device for separating oil from a gas. It comprises a cylindrical vertical axis housing forming a peripheral wall of the device; a top end cap; a bottom end cap; an inlet parallel to the axis of the cylindrical housing extending through the top end cap; a gas outlet formed by a cylindrical wall forming a central passage aligned with the axis; a helical wall formed within the cylindrical housing between the peripheral wall and the cylindrical wall; a conical baffle having a downwardly and outwardly sloping wall spaced below the helical wall; a plurality of apertures extending through an outer rim area of the baffle adjacent to the peripheral wall; an oil collection zone below the baffle; and an oil outlet in the oil collection zone extending through the bottom end cap controlled by a valve.

Westermeyer, G.W.

1992-05-19

355

A novel magnetic ion imprinted nano-polymer for selective separation and determination of low levels of mercury(II) ions in fish samples.  

Science.gov (United States)

In this work a novel ion imprinted polymer (IIP) based on N-(pyridin-2-ylmethyl)ethenamine (V-Pic) was coated on Fe3O4 nano-particles and characterized by thermal gravimetric and differential thermal analysis (TG/DTA), IR spectroscopy, Scanning electron microscopy (SEM) and also elemental analysis. The application of this novel magnetic sorbent was investigated in rapid extraction, preconcentration and also determination of trace amounts of Hg(II) ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). Effect of various parameters such as sample pH, adsorption time and desorption time, maximum capacity and also eluent type and concentration was investigated in this study. The relative standard deviation (RSD%) and limit of detection (LOD) of the method were found to be 1.47% and 0.03ngmL(-1), respectively. The amounts of mercury in some standard reference materials was Also determined using this sorbent in order to confirm the accuracy of this method. Finally, this sorbent was successfully applied for determination of low levels of Hg(II) ions in various fish samples. PMID:23993582

Najafi, Ezzatolla; Aboufazeli, Forouzan; Lotfi Zadeh Zhad, Hamid Reza; Sadeghi, Omid; Amani, Vahid

2013-07-04

356

A novel magnetic ion imprinted nano-polymer for selective separation and determination of low levels of mercury(II) ions in fish samples.  

UK PubMed Central (United Kingdom)

In this work a novel ion imprinted polymer (IIP) based on N-(pyridin-2-ylmethyl)ethenamine (V-Pic) was coated on Fe3O4 nano-particles and characterized by thermal gravimetric and differential thermal analysis (TG/DTA), IR spectroscopy, Scanning electron microscopy (SEM) and also elemental analysis. The application of this novel magnetic sorbent was investigated in rapid extraction, preconcentration and also determination of trace amounts of Hg(II) ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). Effect of various parameters such as sample pH, adsorption time and desorption time, maximum capacity and also eluent type and concentration was investigated in this study. The relative standard deviation (RSD%) and limit of detection (LOD) of the method were found to be 1.47% and 0.03ngmL(-1), respectively. The amounts of mercury in some standard reference materials was Also determined using this sorbent in order to confirm the accuracy of this method. Finally, this sorbent was successfully applied for determination of low levels of Hg(II) ions in various fish samples.

Najafi E; Aboufazeli F; Lotfi Zadeh Zhad HR; Sadeghi O; Amani V

2013-12-01

357

Production of sulfate radical from peroxymonosulfate induced by a magnetically separable CuFe2O4 spinel in water: efficiency, stability, and mechanism.  

UK PubMed Central (United Kingdom)

A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe(2)O(4) spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe(2)O(4) showed higher activity and 30 times lower Cu(2+) leaching (1.5 ?g L(-1) per 100 mg L(-1)) than a well-crystallized CuO at the same dosage. CuFe(2)O(4) maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe(2)O(4) was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe(2)O(4), the radical production yield from PMS was determined to be near 1 mol/mol. The PMS decomposition involved an inner-sphere complexation with the oxide's surface Cu(II) sites. In situ characterization of the oxide surface with ATR-FTIR and Raman during the PMS decomposition suggested that surface Cu(II)-Cu(III)-Cu(II) redox cycle was responsible for the efficient sulfate radical generation from PMS.

Zhang T; Zhu H; Croué JP

2013-03-01

358

Centrifugal separator  

International Nuclear Information System (INIS)

A centrifuge suitable for the enrichment of UF6 is disclosed. A rotary drum disposed within a cylindrical housing is supported between magnetic bearings and a pivot bearing to reduce losses and suppress vibration and is driven by a motor mounted at the lower end of the housing to directly drive the lower end cap of the drum. To reduce windage loss a chamber which is evacuated or filled with helium is defined between the inner cylindrical surface of the housing and the outer cylindrical surface of the drum by sealing means provided at both extremities thereof. To create circular counter currents, supply the gas mixture and eventually exhaust the heavy fraction thereof, a stationary member is fixed to the upper end of the housing and flared into a conically shaped structure the conical surface of which protrudes into the upper portion of the drum. Openings are provided along the conical surface and communicate via a central passage with an external tank for supplying the drum with the gas mixture. Heavier gas fractions are discharged through holes provided at the circumference of the conical member and communicated with an external collection tank via a passage surrounding the central passage, and lighter fractions are discharged through openings in the lower end cap for collection in and removal from a tank disposed therebelow. Heating and cooling elements for producing circulating currents may be eliminated, and turbulence within the drum normally produced by conventional scoop systems is minimized. (Owens, K. J.).

1972-01-01

359

Oil separator  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an oil separator for a horizontal screw compressor: a generally cylindrical member having a closed first end and having a second end having an opening therein for receiving the rotor assembly of a screw compressor; baffle seal means spaced from the closed first end and defining therewith a first chamber; generally horizontal divider plate means extending between the baffle seal means and the second end so as to divide the generally cylindrical member to thereby define second and third chambers with the second chamber being beneath and larger than the third chamber; the opening in the second end communicates with the second chamber whereby the second chamber is adapted to receive the rotor assembly; discharge deflector means in the second chamber for directing compressor discharge upwardly so as to impinge upon the divider plate means and deposit entrained oil thereon; demister means in the second chamber and coacting with the baffle seal means whereby compressor discharge must pass through the demister means to reach the first chamber.

Calupca, G.A.; Crone, L.L.; Maxey, W. III; Rubenic, E.K.

1988-12-06

360

Oil separator  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an apparatus for separating a first liquid from a second liquid of lower specific gravity comprising: a vessel having inlet means for a mixture of the first and second liquids positioned above the liquid level in the vessel and including diffuser means for preventing turbulence in the vessel caused by air and high velocity liquid flow, the diffuser means comprising as inner pipe of holes, and an outer pipe of shorter length the the inner pipe and surrounding the inner pipe for intercepting the mixture passing through the holes and directing the mixture through opposite ends of the outer pipe; a generally vertical conduit in the vessel, the conduit having an inlet in the lower part of the vessel; a generally horizontal conduit sealingly coupled between the vertical conduit and a first opening in a wall of the vessel at a level above the inlet to the vertical conduit. The first opening provides a first outlet for the first liquid such that the first liquid reaches the first outlet only by passing through the inlet to the vertical conduit and such that the horizontal conduit establishes the level of the first liquid in the vessel; and a second outlet for the second liquid comprises a second opening in a wall of the vessel above the level of the first outlet.

Cloud, J.A.

1987-08-04

 
 
 
 
361

Rapid magnetophoretic separation of microalgae.  

UK PubMed Central (United Kingdom)

Magnetic collection of the microalgae Chlorella sp. from culture media facilitated by low-gradient magnetophoretic separation is achieved in real time. A removal efficiency as high as 99% is accomplished by binding of iron oxide nanoparticles (NPs) to microalgal cells in the presence of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) as a binder and subsequently subjecting the mixture to a NdFeB permanent magnet with surface magnetic field ?6000 G and magnetic field gradient <80 T m(-1) . Surface functionalization of magnetic NPs with PDDA before exposure to Chlorella sp. is proven to be more effective in promoting higher magnetophoretic removal efficiency than the conventional procedure, in which premixing of microalgal cells with binder is carried out before the addition of NPs. Rodlike NPs are a superior candidate for enhancing the magnetophoretic separation compared to spherical NPs due to their stable magnetic moment that originates from shape anisotropy and the tendency to form large NP aggregates. Cell chaining is observed for nanorod-tagged Chlorella sp. which eventually fosters the formation of elongated cell clusters.

Lim JK; Chieh DC; Jalak SA; Toh PY; Yasin NH; Ng BW; Ahmad AL

2012-06-01

362

Magnetic nanotubes  

Science.gov (United States)

A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)

2010-11-16

363

Pulsation of magnetic stars  

CERN Multimedia

Some Ap stars with strong magnetic fields pulsate in high order p-modes; they are called roAp (rapidly oscillating Ap) stars. The p-mode frequencies are modified by the magnetic fields. Although the large frequency separation is hardly affected, small separations are modified considerably. The magnetic field also affects the latitudinal amplitude distribution on the surface. We discuss the property of axisymmetric p-mode oscillations in roAp stars.

Saio, Hideyuki

2013-01-01

364

Magnetic nano-beads based separation combined with propidium monoazide treatment and multiplex PCR assay for simultaneous detection of viable Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes in food products.  

UK PubMed Central (United Kingdom)

We developed a rapid and reliable technique for simultaneous detection of Salmonella Typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes that can be used in food products. Magnetic nano-beads (MNBs) based immunomagnetic separation (IMS) was used to separate the target bacterial cells while multiplex PCR (mPCR) was used to amplify the target genes. To detect only the viable bacteria, propidium monoazide (PMA) was applied to selectively suppress the DNA detection from dead cells. The results showed the detection limit of IMS-PMA-mPCR assay was about 10(2) CFU/ml (1.2 × 10(2) CFU/ml for S. Typhimurium, 4.0 × 10(2) CFU/ml for E. coli O157:H7 and 5.4 × 10(2) CFU/ml for L. monocytogenes) in pure culture and 10(3) CFU/g (5.1 × 10(3) CFU/g for S. Typhimurium, 7.5 × 10(3) CFU/g for E. coli O157:H7 and 8.4 × 10(3) CFU/g for L. monocytogenes) in spiking food products samples (lettuce, tomato and ground beef). This report has demonstrated for the first time, the effective use of rapid and reliable IMS combined with PMA treatment and mPCR assay for simultaneous detection of viable S. Typhimurium, E. coli O157:H7 and L. monocytogenes in spiked food samples. It is anticipated that the present approach will be applicable to simultaneous detection of the three target microorganisms for practical use.

Yang Y; Xu F; Xu H; Aguilar ZP; Niu R; Yuan Y; Sun J; You X; Lai W; Xiong Y; Wan C; Wei H

2013-06-01

365

LEP beam separator at L3  

CERN Multimedia

During injection and acceleration, separators like this were used to keep the electron and positron beams apart while they travelled in the vacuum chamber. When the beams reached maximum energy the separators at the experiments were turned off, allowing the beams to collide. This one was located near the L3 experiment, whose huge red solenoid magnet can be seen in the background.

1989-01-01

366

Measurement of the elastic electron-proton cross section and separation of the electric and magnetic form factor in the Q2 range from 0.004 to 1 (GeV/c)2  

International Nuclear Information System (INIS)

The electromagnetic form factors of the proton are fundamental quantities sensitive to the distribution of charge and magnetization inside the proton. Precise knowledge of the form factors, in particular of the charge and magnetization radii provide strong tests for theory in the non-perturbative regime of QCD. However, the existing data at Q2 below 1 (GeV/c)2 are not precise enough for a hard test of theoretical predictions. For a more precise determination of the form factors, within this work more than 1400 cross sections of the reaction H(e, e')p were measured at the Mainz Microtron MAMI using the 3-spectrometer-facility of the A1-collaboration. The data were taken in three periods in the years 2006 and 2007 using beam energies of 180, 315, 450, 585, 720 and 855 MeV. They cover the Q2 region from 0.004 to 1 (GeV/c)2 with counting rate uncertainties below 0.2% for most of the data points. The relative luminosity of the measurements was determined using one of the spectrometers as a luminosity monitor. The overlapping acceptances of the measurements maximize the internal redundancy of the data and allow, together with several additions to the standard experimental setup, for tight control of systematic uncertainties. To account for the radiative processes, an event generator was developed and implemented in the simulation package of the analysis software which works without peaking approximation by explicitly calculating the Bethe-Heitler and Born Feynman diagrams for each event. To separate the form factors and to determine the radii, the data were analyzed by fitting a wide selection of form factor models directly to the measured cross sections. These fits also determined the absolute normalization of the different data subsets. The validity of this method was tested with extensive simulations. The results were compared to an extraction via the standard Rosenbluth technique. The dip structure in GE that was seen in the analysis of the previous world data shows up in a modi ed form. When compared to the standard-dipole form factor as a smooth curve, the extracted GE exhibits a strong change of the slope around 0.1 (GeV/c)2, and in the magnetic form factor a dip around 0.2 (GeV/c)2 is found. This may be taken as indications for a pion cloud. For higher Q2, the fits yield larger values for GM than previous measurements, in agreement with form factor ratios from recent precise polarized measurements in the Q2 region up to 0.6 (GeV/c)2. The charge and magnetic rms radii are determined as left angle re right angle =0.879± 0.005stat. ± 0.004syst. ± 0.002model ± 0.004group fm; left angle rm right angle =0.777 ± 0.013stat. ± 0.009syst. ± 0.005model ± 0.002group fm. This charge radius is significantly larger than theoretical predictions and than the radius of the standard dipole. However, it is in agreement with earlier results measured at the Mainz linear accelerator and with determinations from Hydrogen Lamb shift measurements. The extracted magnetic radius is smaller than previous determinations and than the standard-dipole value. (orig.)

2010-01-01

367

APIARY B-Factory Separation Scheme  

Energy Technology Data Exchange (ETDEWEB)

A magnetic beam-separation scheme for an asymmetric-energy B Factory based on the SLAC electron-positron collider PEP is described that has the following properties: the beams collide head-on and are separated magnetically with sufficient clearance at the parasitic crossing points and at the septum, the magnets have large beam-stay-clear apertures, synchrotron radiation produces low detector backgrounds and acceptable heat loads, and the peak {beta}-function values and contributions to the chromaticities in the IR quadrupoles are moderate.

Garren, A.; Sullivan, M.

1991-05-03

368

Activated Carbon Composites for Air Separation  

Energy Technology Data Exchange (ETDEWEB)

In continuation of the development of composite materials for air separation based on molecular sieving properties and magnetic fields effects, several molecular sieve materials were tested in a flow system, and the effects of temperature, flow conditions, and magnetic fields were investigated. New carbon materials adsorbents, with and without pre-loaded super-paramagnetic nanoparticles of Fe3O4 were synthesized; all materials were packed in chromatographic type columns which were placed between the poles of a high intensity, water-cooled, magnet (1.5 Tesla). In order to verify the existence of magnetodesorption effect, separation tests were conducted by injecting controlled volumes of air in a flow of inert gas, while the magnetic field was switched on and off. Gas composition downstream the column was analyzed by gas chromatography and by mass spectrometry. Under the conditions employed, the tests confirmed that N2 - O2 separation occurred at various degrees, depending on material's intrinsic properties, temperature and flow rate. The effect of magnetic fields, reported previously for static conditions, was not confirmed in the flow system. The best separation was obtained for zeolite 13X at sub-ambient temperatures. Future directions for the project include evaluation of a combined system, comprising carbon and zeolite molecular sieves, and testing the effect of stronger magnetic fields produced by cryogenic magnets.

Contescu, Cristian I [ORNL; Baker, Frederick S [ORNL; Tsouris, Costas [ORNL; McFarlane, Joanna [ORNL

2008-03-01

369

Introduction to Magnetic Monopoles  

CERN Document Server

One of the most basic properties of magnetism is that a magnet always has two poles, north and south, which cannot be separated into isolated poles, i.e., magnetic monopoles. However, there are strong theoretical arguments why magnetic monopoles should exist. In spite of extensive searches they have not been found, but they have nevertheless played a central role in our understanding of physics at the most fundamental level.

Rajantie, Arttu

2012-01-01

370

A separability parameter for dielectrophoretic cell separation.  

Science.gov (United States)

In this study, a separability parameter is introduced to determine the selection of optimum operating parameters for DEP separation of a cell pair. The separability parameter is defined as a function of cells' Clausius-Mossotti (CM) factors. T-cell leukemia Jurkat and mouse melanoma B16 cells are tested to validate the separability parameter. CM factors of cells are measured using a recently developed microfluidic impedance spectroscopy device. Separability maps are generated for varying values of field frequency and buffer conductivity. Cell separation is tested using a planar interdigitated electrode array at different buffer conductivities. Impedance measurements of the DEP device are performed at various buffer conductivities. Electrode polarization effects and energy allocation for dielectrophoretic manipulation of cells are computed from the impedance data utilizing an equivalent circuit model. Cell separation results are explained in the light of the impedance measurements. PMID:23348751

Sabuncu, Ahmet C; Beskok, Ali

2013-03-07

371

A separability parameter for dielectrophoretic cell separation.  

UK PubMed Central (United Kingdom)

In this study, a separability parameter is introduced to determine the selection of optimum operating parameters for DEP separation of a cell pair. The separability parameter is defined as a function of cells' Clausius-Mossotti (CM) factors. T-cell leukemia Jurkat and mouse melanoma B16 cells are tested to validate the separability parameter. CM factors of cells are measured using a recently developed microfluidic impedance spectroscopy device. Separability maps are generated for varying values of field frequency and buffer conductivity. Cell separation is tested using a planar interdigitated electrode array at different buffer conductivities. Impedance measurements of the DEP device are performed at various buffer conductivities. Electrode polarization effects and energy allocation for dielectrophoretic manipulation of cells are computed from the impedance data utilizing an equivalent circuit model. Cell separation results are explained in the light of the impedance measurements.

Sabuncu AC; Beskok A

2013-04-01

372

Bi-selective mass separator  

International Nuclear Information System (INIS)

During the SPIRAL2 'detailed engineering study' several designs for a mass separator were proposed. This separator should deliver, subsequently to the 'production target/ion source system', simultaneously two beams of different masses, one towards the low energy area (DESIR), the second towards the CIME post accelerator through the charge breeder). We had a hard time in following the specifications: two beam lines with a resolving power larger than 250 requiring only a 15 mass difference between both simultaneous beams. A fully magnetic approach is proposed, made of four dipoles. A first Elbek type dipole distributes the ions along parallel trajectories. A second one of the same type is placed in opposition and ensures for the left way the selection of one of the light masses. A third dipole deflects the heavy masses analysed by the first dipole, preserves their parallel trajectories and provides a reorientation of the beam. A fourth Elbek type dipole ensures for the right way the selection of one of the heavy masses. Optical simulations are performed in a realistic magnetic structure for the four dipole magnets.

2008-01-01

373

The isotopic contamination in electromagnetic isotope separators  

International Nuclear Information System (INIS)

[en] In the early years of isotope separation, and in particular electromagnetic isotope separation, needs for rapid results have conducted to empiric research. This paper describes fundamental research on the electromagnetic isotope separation to a better understanding of isotope separators as well as improving the performances. Focus has been made on the study of the principle of isotope contamination and the remedial action on the separator to improve the isotope separation ratio. In a first part, the author come back to the functioning of an electromagnetic separator and generalities on isotope contamination. Secondly, it describes the two stages separation method with two dispersive apparatus, an electromagnetic separation stage followed by an electrostatic separation stage, both separated by a diaphragm. The specifications of the electrostatic stage are given and its different settings and their consequences on isotope separation are investigated. In a third part, mechanisms and contamination factors in the isotope separation are discussed: natural isotope contamination, contamination by rebounding on the collector, contamination because of a low resolution, contamination by chromatism and diffusion effect, breakdown of condenser voltage. Analysis of experimental results shows the diffusion as the most important contamination factor in electromagnetic isotope separation. As contamination factors are dependent on geometric parameters, sector angle, radius of curvature in the magnetic field and clearance height are discussed in a fourth part. The better understanding of the mechanism of the different contamination factors and the study of influential parameters as pressure and geometric parameters lead to define a global scheme of isotope contamination and determinate optima separator design and experimental parameters. Finally, the global scheme of isotope contamination and hypothesis on optima specifications and experimental parameters has been checked during a series of experiments for the separation of cadmium isotopes. (M.P.)

1959-01-01

374

Zirconium isotope separation  

International Nuclear Information System (INIS)

In this invention, a bond in a zirconium compound is broken and when broken, can undergo a reaction with another compound. Since zirconium 91 has an odd number of nucleons, it will have its own magnetic field which will relax the spins of the electrons in the broken bonds faster than the spins will relax in even-numbered isotopes such as zirconium 90. This means that the broken bonds in the zirconium 91 isotope will be slower to reform and therefore will be more likely to engage in a reaction with the scavenger compound than will the broken bonds of the even zirconium isotopes. As a result the original zirconium compound will become depleted in the zirconium 91 isotope and the reaction product of the original zirconium compound with the scavenger will become enriched in the zirconium 91 isotope. Since the reaction product is chemically different from the original compound, it can then be easily separated. The preferred compound is tetraoxylatozirconate (IV). The solvent is preferably water and the preferred scavenger is Clsup(-).

1981-06-04

375

Separators for SLAC B-Factory  

Energy Technology Data Exchange (ETDEWEB)

In order to separate the beams during injection, a closed vertical bump will be introduced in the B-Factory High Energy Ring (HER) using four dedicated, pulsed magnets. The design field in the magnets is B{sub 0} = 660 G; the field integrals of the magnets are nominally: {integral} Hdl = 0.0450 T{center_dot}m; {integral} Hdl = 0.0420 T{center_dot}m; {integral} Hdl = 0.0756 T{center_dot}m; {integral} Hdl = 0.0832 T{center_dot}m. The magnet apertures are 15 cm horizontal along the field direction and 10 cm in the vertical direction. The beams will be separated with a rise time of about 200 ms at the end of a coast and brought back into collision within about 1 ms. A good-field-region of {+-} 4.1 cm in the horizontal and {+-} 2.1 cm in the vertical direction with field non-uniformity less than 0.2% is aimed for, and fast magnetic field switch-off even through the present steel vacuum pipe of about 4 mm thickness. A 15% variation in each magnet current is done with variable shunts to allow tuning of the bump for different lattice configurations. The magnets have to fit into the existing constrained space of the B-factory. The magnets have been made and tested successfully at BINP and at SLAC. The whole system including pulsed power supply and shunts were also tested successfully.

MacNair, Dave

2002-08-21

376

Isobar separator for radioactive nuclear beams project  

Energy Technology Data Exchange (ETDEWEB)

In order to produce pure beams of radioactive products emanating from the production target/ion source system, both mass and isobar separation is required. A preliminary mass separation with a resolution {triangle}M/M of approximately 10{sup -3} will select the proper mass beam. An isobar separator is needed because the masses of adjacent isobars are usually quite close, especially for beams near stability. In general, a mass resolution of 5 x 10{sup -5} is needed for isobar separation in the A < 120 region, while a resolution of 3 x 10{sup -5} or better is needed for heavier masses. Magnets are used to obtain mass separation. However, in addition to having mass dispersion properties, magnets also have an equal energy dispersion. This means that an energy variation in the beam cannot be distinguished from a mass difference. This is important because ions emerge from the ion source having a small ({approximately} 10{sup -5} - 10{sup -4}) energy spread. In order to make the system respond only to mass differences, it must be made energy dispersion. This is normally accomplished by using a combination of electric and magnetic fields. The most convenient way of doing this is to use an electric deflection following the magnet separator. A preliminary isobar separator which achieves a mass resolution of 2.7 x 10{sup -5} is shown in Figure I-38. It uses two large 60{degrees} bending magnets to obtain a mass dispersion of 140 mm/%, and four electric dipoles with bending angles of 39{degrees} to cancel the energy dispersion. Sextupole and octupole correction elements are used to reduce the geometrical aberrations.

Davids, C.N.; Nolen, J.A.

1995-08-01

377

Isotope separation by ionic cyclotron resonance  

International Nuclear Information System (INIS)

The principle of the process of isotopic separation by ionic cyclotron resonance is explained succinctly. The theoretical calculation of the isotopic effect is given as functions of the electric and magnetic fields in the frame of single particle approximation and of plasma collective theory. Then, the main parts of the demonstration device which is in operation at the CEA, are described here: the supraconducting magnetic field, the used diagnostics, the principle of the source and the collecting apparatus. Some experimental results are given for chromium. The application of the process to ponderal separation of metal isotopes, as chromium, nickel and molybdenum is discussed in view of production of medical, structural and irradiation isotopes

1986-10-01

378

New separation technique. Catalytically functionated separation membrane  

Energy Technology Data Exchange (ETDEWEB)

This report introduces research examples, showing the fundamental principle of the membrane by separating the catalytically functionated separation membrane into enzyme fixing separation membrane, polymerized metal complex separation membrane and polymer catalyst separation membrane. This membrane can achieve both functions of separation and catalytic reaction simultaneously and has sufficient possibility to combine powerful functions. Enzyme fixing separation membrane is prepared by carrier combination method, bridging method or covering method and the enzyme fixing method with polymerized complex in which enzyme is controlled to prevent the activity lowering as much as possible and enzyme is fixed from an aqueous solution into polymer membrane. This membrane is applied to the continuous manufacturing of invert sugar from cane sugar and adsorption and removing of harmful substances from blood by utilizing both micro-capsuled urease and active carbon. Alginic acid-copper (II) complex membrane is used for the polymerized metal complex membrane and polystyrene sulfonate membrane is used for the polymer catalyst separation membrane. 28 refs., 4 figs., 1 tabs.

Urgami,Tadashi (Kansai Univ., Osaka (Japan))

1989-02-01

379

Study of flow fractionation characteristics of magnetic chromatography utilizing high-temperature superconducting bulk magnet  

Directory of Open Access Journals (Sweden)

Full Text Available We present numerical simulation of separating magnetic particles with different magnetic susceptibilities by magnetic chromatography using a high-temperature superconducting bulk magnet. The transient transport is numerically simulated for two kinds of particles having different magnetic susceptibilities. The time evolutions were calculated for the particle concentration in the narrow channel of the spiral arrangement placed in the magnetic field. The field is produced by the highly magnetized high-temperature superconducting bulk magnet. The numerical results show the flow velocity difference of the particle transport corresponding to the difference in the magnetic susceptibility, as well as the possible separation of paramagnetic particles of 20 nm diameter.

Satoshi Fukui, Yoshihiro Shoji, Jun Ogawa, Tetsuo Oka, Mitsugi Yamaguchi, Takao Sato, Manabu Ooizumi, Hiroshi Imaizumi and Takeshi Ohara

2009-01-01

380

Superconducting magnets  

International Nuclear Information System (INIS)

[en] A superconductor is an electrical conductor which is capable of carrying a 'Supercurrent' and the transmission of energy is 'loss-less'. If such conductors were generally available the implications for industries would be enormous. Unfortunately, superconductivity occurs only in certain materials under certain conditions. The transition of any superconductor from the superconducting mode to 'normal' or resistive mode is a function of absolute temperature, current density within the conductor and local magnetic field intensity. If any one of these parameters exceeds a certain 'critical value' superconductivity is destroyed. Superconducting magnets for high energy physics and medical imaging are discussed. Experience gained in the maturing medical imaging industry has demonstrated beyond doubt that superconducting magnets, even at liquid helium temperatures can today be regarded as industrial pieces of electrical machinery. The advances in magnet stability, cryogenic engineering and refrigeration technology make it feasible for superconductivity to be considered seriously for other electrical engineering applications such as, for example, energy storage, levitation and magnetic separation of ores and minerals. Whereas the impact of the new high temperature superconductors on electrical engineering can at present only be imagined, there is general agreement that ambient temperature superconducting electrical machinery will not be generally available for at least another decade. However, when it does come, electrical engineering will be altered immeasurably. 4 figs., 1 tab

1988-01-01

 
 
 
 
381

Thermosensitive magnetic fluids  

International Nuclear Information System (INIS)

Magnetic core-shell particles were synthesized by the attachment of a polymeric brush on the surface of magnetite nanoparticles. The hybrid particles are well dispersible in good solvents for the polymeric shell and form thermoreversible magnetic fluids in carrier fluids with a critical solution behaviour. The thermoresponsive effect can be activated by the application of a high frequency electromagnetic field and may be useful for magnetic separation, recoverable catalysts and for drug release purposes.

2006-09-27

382

Freely oriented portable superconducting magnet  

Energy Technology Data Exchange (ETDEWEB)

A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.

Schmierer, Eric N. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM)

2010-01-12

383

Protein purification using magnetic adsorbent particles  

DEFF Research Database (Denmark)

The application of functionalised magnetic adsorbent particles in combination with magnetic separation techniques has received considerable attention in recent years. The magnetically responsive nature of such adsorbent particles permits their selective manipulation and separation in the presence of other suspended solids. Thus, it becomes possible to magnetically separate selected target species directly out of crude biological process liquors (e.g. fermentation broths, cell disruptates, plasma, milk, whey and plant extracts) simply by binding them on magnetic adsorbents before application of a magnetic field. By using magnetic separation in this way, the several stages of sample pretreatment (especially centrifugation, filtration and membrane separation) that are normally necessary to condition an extract before its application on packed bed chromatography columns, may be eliminated. Magnetic separations are fast, gentle, scaleable, easily automated, can achieve separations that would be impossible or impractical to achieve by other techniques, and have demonstrated credibility in a wide range of disciplines, including minerals processing, wastewater treatment, molecular biology, cell sorting and clinical diagnostics. However, despite the highly attractive qualities of magnetic methods on a process scale, with the exception of wastewater treatment, few attempts to scale up magnetic operations in biotechnology have been reported thus far. The purpose of this review is to summarise the current state of development of protein separation using magnetic adsorbent particles and identify the obstacles that must be overcome if protein purification with magnetic adsorbent particles is to find its way into industrial practice.

Franzreb, M; Siemann-Herzberg, M.

2006-01-01

384

Magnetic silica colloids for catalysis  

Science.gov (United States)

Monodisperse magnetizable colloidal silica particles in a stable dispersion have been functionalized with a homogeneous catalyst: a PCP pincer Pd-complex. In a proof-of-principle experiment we demonstrate the catalytic activity of the colloids in a C C bond formation reaction. Advantages of the magnetic silica carriers are the large surface-to-volume ratio and the easy recovery by magnetic separation. After magnetic separation, the catalyst-loaded particles are readily redispersed for further use.

Maria Claesson, E.; Mehendale, Nilesh C.; Klein Gebbink, Robertus J. M.; van Koten, Gerard; Philipse, Albert P.

2007-04-01

385

Magnetic silica colloids for catalysis  

International Nuclear Information System (INIS)

[en] Monodisperse magnetizable colloidal silica particles in a stable dispersion have been functionalized with a homogeneous catalyst: a PCP-pincer Pd-complex. In a proof-of-principle experiment we demonstrate the catalytic activity of the colloids in a C-C bond formation reaction. Advantages of the magnetic silica carriers are the large surface-to-volume ratio and the easy recovery by magnetic separation. After magnetic separation, the catalyst-loaded particles are readily redispersed for further use

2007-01-01

386

Magnetic silica colloids for catalysis  

Energy Technology Data Exchange (ETDEWEB)

Monodisperse magnetizable colloidal silica particles in a stable dispersion have been functionalized with a homogeneous catalyst: a PCP-pincer Pd-complex. In a proof-of-principle experiment we demonstrate the catalytic activity of the colloids in a C-C bond formation reaction. Advantages of the magnetic silica carriers are the large surface-to-volume ratio and the easy recovery by magnetic separation. After magnetic separation, the catalyst-loaded particles are readily redispersed for further use.

Maria Claesson, E. [Van' t Hoff Laboratory for Physical and Colloid Chemistry, Utrecht University (Netherlands)]. E-mail: e.m.claesson@chem.uu.nl; Mehendale, Nilesh C. [Organic Chemistry and Catalysis, Utrecht University (Netherlands); Klein Gebbink, Robertus J.M. [Organic Chemistry and Catalysis, Utrecht University (Netherlands); Koten, Gerard van [Organic Chemistry and Catalysis, Utrecht University (Netherlands); Philipse, Albert P. [Van' t Hoff Laboratory for Physical and Colloid Chemistry, Utrecht University (Netherlands)

2007-04-15

387

Superconducting magnets and cryogenics: proceedings  

International Nuclear Information System (INIS)

Separate abstracts were prepared for 70 papers in these workshop proceeedings. Topics covered include: superconducting accelerator magnet research and development; superconductor development; electrical measurements; magnet design and construction methods; field correction methods; power schemes and quench protection; cryogenic systems; and magnet measurements

1986-01-01

388

Novel magnetic flux penetration in overdoped La{sub 2-x}Sr{sub x}CuO{sub 4} single crystals: macroscopic phase separation in a heavily overdoped regime  

Energy Technology Data Exchange (ETDEWEB)

Superconducting diamagnetic properties and magnetic flux penetration have been comparatively investigated on two La{sub 2-x}Sr{sub x}CuO{sub 4} single crystals: one underdoped (x=0.092) and the other overdoped (x = 0.24). Both samples have only a single transition when the external field is low. While when a relatively high external field is applied, a large distinction between these two samples is observed: there is only one transition for the underdoped sample, but an unexpected second transition appears for the overdoped sample. Further investigation on the overdoped sample shows that it has a novel property of magnetic flux penetration, which is characterized by the vanishing of the usual central peak near zero field on the magnetization hysteresis loops. This easy penetration of magnetic flux can be understood in the picture of percolative superconductivity due to the inhomogeneous electronic state in a heavily overdoped regime. (author)

Wen, H.H.; Li, S.L.; Zhao, Z.W.; Liu, Z.Y.; Zhao, Z.X. [National Laboratory for Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Beijing (China)

2002-03-01

389

Microfluidics for cell separation.  

UK PubMed Central (United Kingdom)

The need for efficient cell separation, an essential preparatory step in many biological and medical assays, has led to the recent development of numerous microscale separation techniques. This review describes the current state-of-the-art in microfluidics-based cell separation techniques. Microfluidics-based sorting offers numerous advantages, including reducing sample volumes, faster sample processing, high sensitivity and spatial resolution, low device cost, and increased portability. The techniques presented are broadly classified as being active or passive depending on the operating principles. The various separation principles are explained in detail along with popular examples demonstrating their application toward cell separation. Common separation metrics, including separation markers, resolution, efficiency, and throughput, of these techniques are discussed. Developing efficient microscale separation methods that offering greater control over cell population distribution will be important in realizing true point-of-care (POC) lab-on-a-chip (LOC) systems.

Bhagat AA; Bow H; Hou HW; Tan SJ; Han J; Lim CT

2010-10-01

390

Battery separator material  

Energy Technology Data Exchange (ETDEWEB)

A novel, improved battery separator material particularly adaptable for use in maintenance free batteries. The battery separator material includes a diatomaceous earth filler, an acrylate copolymer binder and a combination of fibers comprising polyolefin, polyester and glass fibers.

Bodendorf, W. J.

1985-07-16

391

Automated insect separation system  

UK PubMed Central (United Kingdom)

The automated insect separation system processes an aggregate mixture of insects and other materials so that selected insects are separated from the other components of the mix. Specifically, the aggregate mix is directed into a separator apparatus so that the mix flows vertically through a series of vibrating screens. In the preferred embodiment, the screening process separates two different sizes of mealworm larvae from the aggregate mixture. The mix includes the mealworm larvae, unconsumed food materials (usually wheat bran), and insect frass.

MORALES-RAMOS JUAN A; ROJAS MARIA G; SHAPIRO ILAN DAVID I; TEDDERS W LOUIS

392

Wide angle isotope separator  

International Nuclear Information System (INIS)

[en] A method and apparatus is described for particle separation. The method uses a wide angle radially expanding vapor of a particle mixture. In particular, selective ionization of one isotope type in the particle mixture is produced in a multichamber separator and the ionized isotope type is accelerated out of the path of the vapor expansion for separate collection

1976-01-01

393

Kinetic Gravity Separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Separations by density, such as the separation of non-ferrous scrap into light and heavy alloys, are often realized by means of heavy media. In principle, kinetic gravity separations in water can be faster and cheaper, because they do not rely on suspensions or salt solutions of which the density mu...

Van Kooy, L.; Mooij, M.; Rem, P.

394

Meniscus Membranes For Separation  

Energy Technology Data Exchange (ETDEWEB)

Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

Dye, Robert C. (Irvine, CA); Jorgensen, Betty (Jemez Springs, NM); Pesiri, David R. (Aliso Viejo, CA)

2005-09-20

395

Meniscus membranes for separations  

Energy Technology Data Exchange (ETDEWEB)

Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

Dye, Robert C. (Irvine, CA); Jorgensen, Betty (Jemez Springs, NM); Pesiri, David R. (Aliso Viejo, CA)

2004-01-27

396

Magnet pole tips  

Energy Technology Data Exchange (ETDEWEB)

An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

Thorn, Craig E. (Wading River, NY); Chasman, Chellis (Setauket, NY); Baltz, Anthony J. (Coram, NY)

1984-04-24

397

Membrane separation process  

Energy Technology Data Exchange (ETDEWEB)

A method for separating a mixture into a first fraction and a second fraction is disclosed. The method comprises passing the mixture into a decantation zone where the solution is separated into a first fraction relatively rich in a first compound and a second fraction relatively deficient in the first compound. One of the separated fractions subsequently is passed to a membrane separation zone for further purification. The subject invention is of particular utility in petroleum processing, where the solution passed to the decantation zone may be a petroleum processing fraction, such as filtrate from a dewaxing zone or an extract or raffinate from an extraction separation zone.

West, T.H.; Thompson, J.A.

1984-02-21

398

Dielectrophoretic separation of cells: Continuous separation.  

UK PubMed Central (United Kingdom)

Dielectrophoresis is the movement of particles in non-uniform alternating and direct current (AC, DC) electric fields. When nonuniform electric fields are created between microelectrodes, cells will redistribute themselves around the electrodes, the force holding the cells in place dependig on the local electric field and on the electrical properties of the cells themselves and the suspending medium. Steric drag forces produced by a gentle fluid flow in the chamber can be used to separate cells by selectively lifting cells from potential energy wells produced by the electric field. The technique is demonstrated in the batch separation of bacteria, yeast cells, and plant cells. Continuous separation and extraction of two cell types can be achieved by repeated reversing of the fluid flow direction in phase with the switching on and off of the applied voltage, and the efficacy of the technique is demonstrated for viable and nonviable (heat-treated) yeast cells. (c) 1995 John Wiley & Sons, Inc.

Markx GH; Pethig R

1995-02-01

399

Rapid chemical separations  

CERN Multimedia

A survey is given on the progress of fast chemical separation procedures during the last few years. Fas