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1

Calibración del separador magnético de alta intensidad magnet-lift mlh (13) 111-5 para su uso en el laboratorio de termocronología de la UCV  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: English 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 granítica [...] s 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 pertenecientes 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 sub [...] jected 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 Betijoque´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.

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

2

USE OF SUPERCONDUCTING MAGNETS IN MAGNETIC SEPARATION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A review is given assessing the potential for superconducting high-field magnet systems in magnetic separation. Particular attention is given to the advantages of the reciprocating canister approach to high gradient magnetic separation and to the use of quadrupole magnets in open gradient magnetic separation.

Parker, M.

1984-01-01

3

Magnetic separation for soil decontamination  

International Nuclear Information System (INIS)

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

1993-03-04

4

Magnetic separation for environmental remediation  

International Nuclear Information System (INIS)

High Gradient Magnetic Separation (HGMS) is a form of magnetic separation used to separate solids from other solids, liquids or gases. HGMS uses large magnetic field gradients to separate ferromagnetic and paramagnetic particles from diamagnetic host materials. The technology relies only on physical properties, and therefore separations can be achieved while producing a minimum of secondary waste. Actinide and fission product wastes within the DOE weapons complex pose challenging problems for environmental remediation. Because the majority of actinide complexes and many fission products are paramagnetic, while most host materials are diamagnetic, HGMS can be used to concentrate the contaminants into a low volume waste stream. The authors are currently developing HGMS for applications to soil decontamination, liquid waste treatment, underground storage tank waste treatment, and actinide chemical processing residue concentration. Application of HGMS usually involves passing a slurry of the contaminated mixture through a magnetized volume. Field gradients are produced in the magnetized volume by a ferromagnetic matrix material, such as steel wool, expanded metal, iron shot, or nickel foam. The matrix fibers become trapping sites for ferromagnetic and paramagnetic particles in the host material. The particles with a positive susceptibility are attracted toward an increasing magnetic field gradient and can be extracted from diamagnetic particles, which react in the opposite direction, moving away from the areas of high field gradients. The extracted paramagnetic contaminants are flushed from the matrix fibers when the magnetic field is reduced to zero or when the matrix canister is removed from the magnetic field. Results are discussed for the removal of uranium trioxide from water, PuO2, U, and Pu from various soils (Fernald, Nevada Test Site), and the waste water treatment of Pu and Am isotopes using HGMS

1994-03-13

5

Separation of magnetic field lines  

Energy Technology Data Exchange (ETDEWEB)

The field lines of magnetic fields that depend on three spatial coordinates are shown to have a fundamentally different behavior from those that depend on two coordinates. Unlike two-coordinate cases, a flux tube in a magnetic field that depends on all three spatial coordinates that has a circular cross section at one location along the tube characteristically has a highly distorted cross section at other locations. In an ideal evolution of a magnetic field, the current densities typically increase. Crudely stated, if the current densities increase by a factor {sigma}, the ratio of the long to the short distance across a cross section of a flux tube characteristically increases by e{sup 2{sigma}}, and the ratio of the longer distance to the initial radius increases as e{sup {sigma}}. Electron inertia prevents a plasma from isolating two magnetic field structures on a distance scale shorter than c/{omega}{sub pe}, which is about 10 cm in the solar corona, and reconnection must be triggered if {sigma} becomes sufficiently large. The radius of the sun, R{sub Circled-Dot-Operator }=7 Multiplication-Sign 10{sup 10}cm is about e{sup 23} times larger, so when {sigma} Greater-Than-Or-Equivalent-To 23, two lines separated by c/{omega}{sub pe} at one location can be separated by the full scale of any magnetic structures in the corona at another. The conditions for achieving a large exponentiation, {sigma}, are derived, and the importance of exponentiation is discussed.

Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

2012-11-15

6

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

7

Isogeometric shape optimization of magnetic density separators:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The waste recycling industry increasingly relies on magnetic density separators. These devices generate an upward magnetic force in ferro-fluids allowing to separate the immersed particles according to their mass density. Recently a new separator design that significantly reduces the required amount of permanent magnet material has been proposed. The purpose of this paper is to alleviate the undesired end-effects in this design by altering the shape of the ferromagnetic covers of the...

Dang Manh, N.; Evgrafov, A.; Gravesen, J.; Lahaye, D.

2013-01-01

8

Microfabricated Passive Magnetic Bead separators  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use and manipulation of functionalized magnetic beads for bioanalysis in lab-on-a-chip systems is receiving growing interest. We have developed microfluidic systems with integrated magnetic structures for the capture and release of magnetic beads. The systems are fabricated in silicon by deep reactive ion etching combined with a number of metal deposition and etching steps followed by anodic bonding of a pyrex lid.

2006-01-01

9

Magnetic separation to remove actinides from soils  

International Nuclear Information System (INIS)

Magnetic Separation is a physical separation process that segregates materials in a mixture on the basis of magnetic susceptibility. Because all actinides and their compounds and fission products are paramagnetic and most host materials such as water, graphite, soil, and sand are diamagnetic, magnetic separation methods can be used to extract the actinides from these hosts, concentrating the toxic materials into a low volume waste stream. The technology relies only on physical properties, and therefore separations can be achieved while producing little or no secondary waste. The High Gradient Magnetic Separation (HGMS) is being used at Los Alamos for applications to soil decontamination, liquid waste treatment, underground storage tank waste treatment and chemical processing residue concentration. HGMS involves passing a slurry through a magnetized volume and is used to separate solids from other solids, liquids, or gases. It is most effective on small particles (90 microns and smaller), and is complementary to other separation technologies. Results with non radioactive surrogates and radioactive materials show that over 99% extraction of the paramagnetic components can be achieved

1994-08-21

10

Recycling of WEEE by magnetic density separation:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper introduces a new recycling method of WEEE: Magnetic Density Separation. By using this technology, both grade and recovery rate of recycled products are over 90%. Good separations are not only observed in relatively big WEEE samples, but also in samples with smaller sizes or electrical wires.

Hu, B.; Giacometti, L.; Di Maio, F.; Rem, P. C.

2011-01-01

11

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

12

Magnetic shielding: application to a new magnetic separator and classifier  

International Nuclear Information System (INIS)

In the development of a new magnetic separator and classifier, magnetic shields had to be designed to protect the particles present within the feeding systems, from the influence of the generated magnetic fields. One configuration for the batch mode of operation and three different ones for the continuous mode were designed, all of them presenting a three-layer structure of different magnetic materials. The choice between the three different continuous mode feeding system configurations is done case-by-case based on the magnetic field intensity and in total costs

2004-05-01

13

Magnetic shielding: application to a new magnetic separator and classifier  

Energy Technology Data Exchange (ETDEWEB)

In the development of a new magnetic separator and classifier, magnetic shields had to be designed to protect the particles present within the feeding systems, from the influence of the generated magnetic fields. One configuration for the batch mode of operation and three different ones for the continuous mode were designed, all of them presenting a three-layer structure of different magnetic materials. The choice between the three different continuous mode feeding system configurations is done case-by-case based on the magnetic field intensity and in total costs.

Augusto, P.A. E-mail: pauloaugusto@ieee.org; Augusto, Pedro; Castelo-Grande, Teresa

2004-05-01

14

Dual magnetic separator for TRI?P  

Science.gov (United States)

The TRI?P facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of 21Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested.

Berg, G. P. A.; Dermois, O. C.; Dammalapati, U.; Dendooven, P.; Harakeh, M. N.; Jungmann, K.; Onderwater, C. J. G.; Rogachevskiy, A.; Sohani, M.; Traykov, E.; Willmann, L.; Wilschut, H. W.

2006-05-01

15

Simplified theory of multipole superconducting magnetic separator  

International Nuclear Information System (INIS)

Different configurations of coils have been proposed for multipole superconducting magnetic separators. The analysis of their magnetic fields allowed finding expressions for magnetic force F/sub m/, which depends mainly on the reduced distance d/sub/ tau/ from the winding symmetry surface, (tau being the pole distance and the basic design parameter). Tau can be optimized to give maximum F/sub m/ at a given d/sub i/, e.g., at the middle of the working channel. It has been shown that in the working channel F/sub m/ can be approximated by a linear function of d/sub/ tau/ that allows finding expressions for particle trajectories as well as for main separator characteristics. 10 refs

1981-09-01

16

Magnetic Cell Separation with Electrodeposited Nanowires  

Science.gov (United States)

Ferromagnetic nanowires are demonstrated as an effective tool to apply magnetic forces to cells. The nanowires are made by electrochemical deposition in nanoporous templates, permitting detailed control of their morphology, magnetic properties, and composition. In addition, the nanowires can be functionalized with biologically active molecules based on their surface chemistry. Magnetic cell separations were performed with Ni nanowires 350 nm in diameter and 5-35 µm long in field gradients of 40 T/m. Single -pass separations of NIH-3T3 cells with 35 µm wires achieve 81with 50beads currently in use. After three passes, the efficiency increases to 95discussed. Work supported by DARPA/AFOSR Grant No. F49620-02-1-0307, and by the David and Lucile Packard Foundation Grant No. 2001-17715.

Hultgren, A.; Tanase, M.; Felton, E. J.; Meyer, G. J.; Chen, C. S.; Reich, D. H.

2003-03-01

17

Isotope separation utilizing Zeeman compensated magnetic extraction  

International Nuclear Information System (INIS)

A method and apparatus are described for creating a plasma of ions of one isotope type and magnetically extracting the ions from the plasma without impairing the ionization selectivity and efficiency. In a particle flow of plural isotope types, radiant energy is applied to selectively excite and ionize ions of at least one isotope type without corresponding ionization of particles of other isotope types. A magnetic field is applied to divert the ions of the one isotope type sufficiently to permit separate collection of those ions without the other particle constituents of the flow. The system of the invention balances the requirements for a high magnetic field to provide sufficient diversion before charge exchange with the requirement for a limited magnetic field to prevent interference with the selective ionization process due to Zeeman broadening of the isotope absorption lines. 25 claims, 8 drawing figures

1976-01-01

18

Magnetic phase separation in ordered alloys  

CERN Multimedia

We present a lattice model to study the equilibrium phase diagram of ordered alloys with one magnetic component that exhibits a low temperature phase separation between paramagnetic and ferromagnetic phases. The model is constructed from the experimental facts observed in Cu$_{3-x}$AlMn$_{x}$ and it includes coupling between configurational and magnetic degrees of freedom which are appropriated for reproducing the low temperature miscibility gap. The essential ingredient for the occurrence of such a coexistence region is the development of ferromagnetic order induced by the long-range atomic order of the magnetic component. A comparative study of both mean-field and Monte Carlo solutions is presented. Moreover, the model may enable the study of the structure of the ferromagnetic domains embedded in the non-magnetic matrix. This is relevant in relation to phenomena such as magnetoresistance and paramagnetism.

Marcos, J; Castan, T; Marcos, Jordi; Vives, Eduard; Castan, Teresa

2001-01-01

19

Fundamental study on magnetic separation of organic dyes in wastewater  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to separate dyes in wastewater with high efficiency and speed using High Gradient Magnetic Separation with superconducting magnet. Two main technologies are necessary for magnetic separation; one is magnetic seeding technology to provide ferromagnetism to the substance, and the other is magnetic separation technology using superconducting magnet and magnetic filters. In order to separate organic dyes, it is necessary to clarify the mechanism of magnetic seeding, and to design a suitable magnetic seeding method depending on the kind of object dye. Six kinds of dyes which are widely used in industry were adopted to investigate the possibility of the magnetic seeding and interaction mechanism between dye and ferromagnetic particles. As a result, it was shown that electrostatic interaction is one of the main interactions between organic dye and ferromagnetic particles.

Fang, M., E-mail: fangmeina@qb.see.eng.osaka-u.ac.j [Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mishima, F.; Akiyama, Y.; Nishijima, S. [Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2010-11-01

20

Magnetic separation for treatment of caustic waste  

International Nuclear Information System (INIS)

Magnetic Separation can be applied to selectively extract actinide contaminants from liquid waste streams and to concentrate these toxic materials into a low volume waste stream. LANL's Plutonium Processing Facility generates more than 80% of the total radioactive containing liquid waste treated at the LANL Waste Water Treatment Facility. This effluent is then combined with other liquid waste for continued treatment. Preliminary experimental results on contaminated waste water indicate that 99 to 99.9% extraction of Pu activity can be achieved using HGMS. This represents decontamination levels of ?3 orders of magnitude to levels of 200 to 10 pCi/L. This technology could potentially reduce the Plutonium Facility radioactive waste stream effluents to levels acceptable for industrial waste stream limits

1996-03-24

 
 
 
 
21

Integrated acoustic and magnetic separation in microfluidic channels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With a growing number of cell-based biotechnological applications, there is a need for particle separation systems capable of multiparameter separations at high purity and throughput, beyond what is presently offered by traditional methods including fluorescence activated cell sorting and column-based magnetic separation. Toward this aim, we report on the integration of microfluidic acoustic and magnetic separation in a monolithic device for multiparameter particle separation. Using our devic...

2010-01-01

22

Integrated acoustic and magnetic separation in microfluidic channels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With a growing number of cell-based biotechnological applications, there is a need for particle separation systems capable of multiparameter separations at high purity and throughput, beyond what is presently offered by traditional methods including fluorescence activated cell sorting and column-based magnetic separation. Toward this aim, we report on the integration of microfluidic acoustic and magnetic separation in a monolithic device for multiparameter particle separation. Using our devic...

2009-01-01

23

Density simulations in magnetic fluid-based separators  

Energy Technology Data Exchange (ETDEWEB)

The paper analyses the effect of magnet pole design on the magnetic field distribution in a magnet gap for a magnetic fluid-based separator using a finite element software package for magnet design. Results are compared to measured values. Good agreement was obtained between the simulated and experimental values. The effective densities of the magnetic fluid within the separation zone were modelled by combining magnetic field gradient values and fluid magnetization data. These results also compared well with the observed values. Moreover, the results confirmed the existence of density gradients within the separation zone. Simulation studies were used to demonstrate that non-uniformity in the effective density of the magnetic fluid could be reduced by magnet shape modification.

Fofana, M.; Klima, M.S. [Pennsylvania State University, University Park, PA (United States). Mineral Processing Section

1998-04-01

24

An isotope separation magnet for the injector test experiment (MITE)  

International Nuclear Information System (INIS)

A magnet has been designed for space-charge neutralization studies on the Injector Test Experiment at the Chalk River Nuclear Laboratories. Augmented by suitable collectors, the magnet could also be used for pilot-scale isotope separations. The present report documents the design of this particular magnet and illustrates the process of designing beam transport magnets in general

1988-01-01

25

Study on magnetic separation of nanosized ferromagnetic particles  

Energy Technology Data Exchange (ETDEWEB)

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

Nakao, R; Matuo, Y; Mishima, F; Nishijima, S [Division of Sustainable Energy and Environmental Engineering, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Taguchi, T [Department of Biochemistry, Osaka University Medical School, Suita, Osaka, 565-0871 (Japan)], E-mail: ryo-nakao@qb.see.eng.osaka-u.ac.jp

2009-03-01

26

Integrated acoustic and magnetic separation in microfluidic channels  

DEFF Research Database (Denmark)

With a growing number of cell-based biotechnological applications, there is a need for particle separation systems capable of multiparameter separations at high purity and throughput, beyond what is presently offered by traditional methods including fluorescence activated cell sorting and column-based magnetic separation. Toward this aim, we report on the integration of microfluidic acoustic and magnetic separation in a monolithic device for multiparameter particle separation. Using our device, we demonstrate high-purity separation of a multicomponent particle mixture at a throughput of up to 10(8) particles/hr. (C) 2009 American Institute of Physics. [doi:10.1063/1.3275577

Bruus, Henrik

2009-01-01

27

Development of high gradient magnetic separation system under dry condition  

International Nuclear Information System (INIS)

The interfusion of impurities such as metallic wear debris has been a problem in the manufacturing process of foods, medicines, and industrial products. Gravity separation system and membrane separation system has been used widely for powder separation, however magnetic separation system is much efficient to separate magnetic particles. Magnetic separation system under wet process is used conventionally, however, it has some demerit such as necessity of drying treatment after separation and difficulty of running the system in the cold region and so on. Thus, magnetic separation under dry process is prospective as alternative method. In this paper, we developed high gradient magnetic separation system (HGMS) under dry process. In dry HGMS system, powder coagulation caused by particle interaction is considerable. Powder coagulation causes a blockage of magnetic filters and results in decrease of separation performance of dry HGMS system. In order to investigate the effect of powder coagulation on separation performance, we conducted experiments with two kinds of powdered materials whose cohesive properties are different.

2010-11-01

28

Application of high gradient magnetic separation in nuclear fuel reprocessing  

International Nuclear Information System (INIS)

This paper discusses high gradient magnetic separation (HGMS), a new solids removal technique in which paramagnetic solids can be trapped in a separator by magnetic forces and then flushed out when the field is switched off. Theoretical formulas are presented that enable equipment to be specified at least approximately. The method has important potential advantages for nuclear fuel reprocessing. 25 refs

1981-01-01

29

Magnetic separation of micro-spheres from viscous biological fluids.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-02-21

30

Magnetic separation of micro-spheres from viscous biological fluids  

Science.gov (United States)

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, Haitao; Kaminski, Michael D.; Caviness, Patricia L.; Xianqiao, Liu; Dhar, Promila; Torno, Michael; Rosengart, Axel J.

2007-02-01

31

Magnetic separation of micro-spheres from viscous biological fluids  

Energy Technology Data Exchange (ETDEWEB)

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 Haitao [Department of Neurology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637 (United States); Kaminski, Michael D [Chemical Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Caviness, Patricia L [Department of Neurology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637 (United States); Liu Xianqiao [Department of Neurology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637 (United States); Dhar, Promila [Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL 60616 (United States); Torno, Michael [Department of Neurology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637 (United States); Rosengart, Axel J [Department of Neurology, University of Chicago Pritzker School of Medicine, Chicago, IL 60637 (United States)

2007-02-21

32

High gradient magnetic separation applied to environmental remediation  

International Nuclear Information System (INIS)

High Gradient Magnetic Separation (HGMS) is an application of superconducting magnet technology to the separation of magnetic solids from other solids, liquids, or gases. The production of both high magnetic fields (>4 T) and large field gradients using superconducting magnet technology has made it possible to separate a previously unreachable but large family of paramagnetic materials. This is a powerful technique that can be used to separate widely dispersed contaminants from a host material and may be the only technique available for separating material in the colloidal state. Because it is a physical separation process, no additional waste is generated. We are applying this technology to the treatment of radioactive wastes for environmental remediation. We have conducted tests examining slurries containing nonradioactive, magnetic surrogates. Results from these studies were used to verify our analytical model of the separation process. The model describes the rate process for magnetic separation and is based on a force balance on the paramagnetic species. This model was used to support bench scale experiments and prototype separator design

1993-07-12

33

High gradient magnetic separation applied to environmental remediation  

International Nuclear Information System (INIS)

High gradient magnetic separation (HGMS) is an application of superconducting magnet technology to the separation of magnetic solids from other solids, liquids, or gases. The production of both high magnetic fields (>4 T) and large field gradients using superconducting magnet technology has made it possible to separate a previously unreachable but large family of paramagnetic materials. This powerful technique can be used to separate widely dispersed contaminants from a host material, and it may be the only technique available for separating material in the colloidal state. Because it is a physical separation process, no additional waste is generated. The authors are applying this technology to the treatment of radioactive wastes for environmental remediation. They have conducted tests examining slurries containing nonradioactive, magnetic surrogates. Results from these studies were used to verify their analytical model of the separation process. The model describes the rate process for magnetic separation and is based on a force balance on the paramagnetic species. This model was used to support bench scale experiments and prototype separator designs

1993-07-12

34

Isotope separation method in axially symmetric opposite magnet field system  

International Nuclear Information System (INIS)

Isotope separation in axially symmetric opposite magnet field system is discussed. Cost of work shows that it is on one order less than at using other methods. Experiments on Li-6 and Li-7 separation show its high efficiency. Parameters of installation for U-235 and U-238 separation are given

2000-01-01

35

Microstripes for transport and separation of magnetic particles  

DEFF Research Database (Denmark)

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. (C) 2012 American Institute of Physics.

Donolato, Marco; Dalslet, Bjarke Thomas

2012-01-01

36

MAGNETITE RECOVERY IN COAL WASHING BY HIGH GRADIENT MAGNETIC SEPARATION  

Science.gov (United States)

The report describes a demonstration of the successful recovery of magnetite from mixtures of magnetite and coal, like those found in a coal-washing circuit, by High Gradient Magnetic Separation. The demonstration was part of a research program at Francis Bitter National Magnet L...

37

Electromagnet with two coils separated by magnetic wall  

International Nuclear Information System (INIS)

The electromagnet comprises a magnetic core with a magnetic wall fixed to it separating two coaxial coils, a casing surrounding the coils and magnetically coupled to the wall, and a carrying face at the end of the casing, arranged so that the carrying force exerted by energising one of the coils is less than that exerted by energising the other. The invention applies for holding nuclear reactor control rods. The force exerted on a control rod can be varied with its position

1984-09-24

38

Superconducting magnetic separation device and operation method thereof  

International Nuclear Information System (INIS)

The present invention is useful as a technique for purifying liquid from a reprocessing step for spent nuclear fuels. That is, taking advantages of superconducting magnetic separation technique, desorption operation of fine particles in the liquid to be processed is facilitated. Superconducting magnetic shields which can be inserted/withdrawn are disposed in a space between magnetic filters and superconducting electromagnets. The liquid to be processed is passed through the magnetic filters disposed in strong magnetic fields of the superconducting electromagnets. Fine particles in the liquid to be processed are separated by deposition onto the filter materials and separated. Accordingly, the liquid to be processed can be purified. Upon cleaning the filters, the superconducting magnetic shields are inserted and moved so as to surround the magnetic filters, to prevent the magnetic fields from exerting the filters. With such a constitution, excitation and demagnetization relative to the magnetic filters can be switched efficiently with no ON/OFF operation to electric current for superconducting coils. (I.S.)

1992-05-15

39

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

40

Simulation of recoil trajectories in gas-filled magnetic separators  

International Nuclear Information System (INIS)

A computer code has been developed to simulate the production of heavy element compound nucleus recoils and their trajectories through gas-filled magnetic separators. The simulation is carried out in three steps: positions and trajectories of heavy element recoils in the target layer, propagation through remaining target material, and trajectories through the gas-filled separator. Separators with quite different magnetic configurations are modeled: the Berkeley gas-filled separator (BGS) and two magnetic configurations for the TransActinide separator and chemistry apparatus (TASCA). While computing trajectories through the gas-filled separator, special attention is paid to the charge exchange/equilibration and scattering in the gas. New features of these simulations include mixed He/H2/N2 gas operation and a gas density (pressure) effect. Numerical procedures used in the simulations are explained in detail. Results of the simulations are presented, showing the gas mixtures/pressures that result in the highest efficiency for collecting compound nucleus recoils at the focal plane of the gas-filled separator. Comparison between simulation and experimental results are presented for average recoil ion charge in various gases, focal plane image size, and magnetic rigidity dispersion

2013-05-21

 
 
 
 
41

Use of high gradient magnetic separation for actinide application  

International Nuclear Information System (INIS)

Decontamination of materials such as soils or waste water that contain radioactive isotopes, heavy metals, or hazardous components is a subject of great interest. Magnetic separation is a physical separation process that segregates materials on the basis of magnetic susceptibility. Because the process relies on physical properties, separations can be achieved while producing a minimum of secondary waste. Most traditional physical separation processes effectively treat particles larger than 70 microns. In many situations, the radioactive contaminants are found concentrated in the fine particle size fraction of less than 20 microns. For effective decontamination of the fine particle size fraction most current operations resort to chemical dissolution methods for treatment. High gradient magnetic separation (HGMS) is able to effectively treat particles from 90 to ?0.1 micron in diameter. The technology is currently used on the 60 ton per hour scale in the kaolin clay industry. When the field gradient is of sufficiently high intensity, paramagnetic particles can be physically captured and separated from extraneous nonmagnetic material. Because all actinide compounds are paramagnetic, magnetic separation of actinide containing mixtures is feasible. The advent of reliable superconducting magnets also makes magnetic separation of weakly paramagnetic species attractive. HGMS work at Los Alamos National Laboratory (LANL) is being developed for soil remediation, waste water treatment and treatment of actinide chemical processing residues. LANL and Lockheed Environmental Systems and Technologies Company (LESAT) have worked on a co-operative research and development agreement (CRADA) to develop HGMS for radioactive soil decontamination. The program is designed to transfer HGMS from the laboratory and other industries for the commercial treatment of radioactive contaminated materials. 9 refs., 2 figs., 2 tabs

1996-07-07

42

Differential magnetic catch and release: analysis and separation of magnetic nanoparticles.  

Science.gov (United States)

This article reports the purification and separation of magnetic nanoparticle mixtures using differential magnetic catch and release (DMCR). This method applies a variable magnetic flux orthogonal to the flow direction in an open tubular capillary to trap and controllably release magnetic nanoparticles. Magnetic moments of 8, 12, and 17 nm diameter CoFe2O4 nanoparticles are calculated using the applied magnetic flux and experimentally determined force required to trap 50% of the particle sample. Balancing the relative strengths of the drag and magnetic forces enables separation and purification of magnetic CoFe2O4 nanoparticle samples with <20 nm diameters. Samples were characterized by transmission electron microscopy to determine the average size and size dispersity of the sample population. DMCR is further demonstrated to be useful for separation of a magnetic nanoparticle mixture, resulting in samples with narrowed size distributions. PMID:19891452

Beveridge, Jacob S; Stephens, Jason R; Latham, Andrew H; Williams, Mary Elizabeth

2009-12-01

43

Ultrasound imaging for quantitative evaluation of magnetic density separation:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis is dedicated to an investigation of the potential and technological possibilities of an inline ultrasound system as a quality control system for wet recycling of solid waste. The main targeted recycling technology is magnetic density separation (MDS), a novel technique that was investigated and technologically matured in a project running in parallel to this work. In MDS, the easily magnetisable ferrofluid is used as the separation medium to sort different materials based on their...

Sanaee, S. A.

2013-01-01

44

Magnetic field analysis of high gradient magnetic separator via finite element analysis  

Energy Technology Data Exchange (ETDEWEB)

High Gradient Magnetic Separator (HGMS) 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 the magnetic flux density alone. So the HGMS shows excellent performance compared with other magnetic separators. These matrices are usually composed of stainless wires having high magnetization characteristics. This paper deals with superconducting HGMS which is aimed for purifying wastewater by using stainless steel matrix. Background magnetic field up to 6 T is generated by a superconducting solenoid and the stainless steel matrices are arranged inside of the solenoid. In order to calculate magnetic forces exerting on magnetic particles in wastewater, it is important to calculate magnetic field and magnetic field gradient those are proportional to the magnetic force acting on the particle. So we presents magnetic field distribution analysis result and estimates how many times of magnetic force will act on a particle when the matrix are arranged or not. Magnetic field is calculated in 3 dimensions by using Finite Element Method (FEM) and also compared with results obtained from 2 dimensional analysis.

Baik, S.K., E-mail: skbaik@keri.re.kr [Korea Electrotechnology Research Institute, Seongju-dong 28-1, Changwon (Korea, Republic of); Ha, D.W.; Ko, R.K.; Kwon, J.M. [Korea Electrotechnology Research Institute, Seongju-dong 28-1, Changwon (Korea, Republic of)

2012-10-15

45

Dual magnetic separator for TRI{mu}P  

Energy Technology Data Exchange (ETDEWEB)

The TRI{mu}P facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of {sup 21}Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested.

Berg, G.P.A. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands)]. E-mail: gpberg@bergs.com; Dermois, O.C. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Dammalapati, U. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Dendooven, P. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Harakeh, M.N. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Jungmann, K. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Onderwater, C.J.G. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Rogachevskiy, A. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Sohani, M. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Traykov, E. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Willmann, L. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands); Wilschut, H.W. [Kernfysisch Versneller Instituut, Zernikelaan 25, 9747 AA Groningen (Netherlands)

2006-05-10

46

Dual Magnetic Separator for TRI$\\mu$P  

CERN Document Server

The TRI$\\mu$P facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of $^{21}$Na isotopes, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested.

Berg, G P A; Dammalapati, U; Harakeh, M N; Jungmann, Klaus; Onderwater, Gerco; Rogachevskiy, A; Sohani, M; Traykov, E; Willmann, L; Wilschut, H W

2006-01-01

47

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 (<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.

2011-02-01

48

High-frequency magnet for separating beams in colliders  

International Nuclear Information System (INIS)

A prototype 130 kHz ferrite-cored magnet designed for separating bunched beams of protons and antiprotons in a high-energy collider has been built and tested in vacuum up to 620 gauss. The main problems are the removal of the power dissipated in the ferrite and the withstand voltage of the coil in relation to the yoke

1984-01-01

49

Separation of variables in BC-type Gaudin magnet  

CERN Document Server

The integrable system is introduced based on the Poisson rs -matrix structure. This is a generalization of the Gaudin magnet, and in SL(2) case isomorphic to the generalized Neumann model. The separation of variables is discussed for both classical and quantum case.

Hikami, K

1995-01-01

50

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 Jupiterâ??s moons, Ganymede.

Olsen, Nils

2010-01-01

51

Separation of the Magnetic Field into External and Internal Parts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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; Jia, X.

2010-01-01

52

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

53

Maximizing the recovery of fine iron ore using magnetic separation  

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english The beneficiation of fine iron ore will increase in importance in the future because most new iron ore resources will be in the form of lower grade ore deposits that will require liberation of iron ore minerals at finer sizes. Generally this fine iron ore will be benefi-ciated to produce a pelletizi [...] ng concentrate with very strict chemical and physical specifications. In addition, because of the increasing demand for iron ore there are now more opportunities to produce by-product iron ore from mining operations producing other commodities. In the past the associated iron ore minerals would report to final tailings but now there is potential value to be realised from by-product revenue. These by-product iron ore opportunities are almost all centred on producing pelletizing concentrate. Currently pelletizing concentrates are produced mainly by various combinations of flotation and magnetic separation. The selection of the beneficiation route will depend on ore mineralogy and considerations around plant capacity and final concentrate quality. The main economic iron minerals are magnetic, haematite being paramagnetic and magnetite being ferromagnetic. This, therefore, means that magnetic separation can be applied, in principle, to all fine iron-ore beneficiation plants. While flotation has a considerable capacity advantage over magnetic separation, the real advantage of magnetic separation over flotation in fine iron-ore beneficiation is that treatment of -10 µm iron ore is possible-in flotation, the feed is deslimed at 10 µm and the -10 µm stream is considered to be final tailings, even though there is often a significant amount of contained iron ore. This paper describes a study around the recovery of fine magnetite in the form of a pelletizing concentrate. The study is based on an evaluation of an iron ore by-product opportunity from an iron oxide copper-gold (IOCG) deposit. Experiments were conducted to quantify the differences in magnetic separation performance with decrease in particle size treated. A mineralogical evaluation of all the test work products was undertaken to facilitate the interpretation of the test work results. These results were then used to propose an economically viable flowsheet for maximizing fine magnetite recovery using magnetic separation.

M, Dworzanowski.

54

Separation of impurity in molten metals by using superconducting magnet  

International Nuclear Information System (INIS)

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

55

Separation of magnetization precession in 3He-B into two magnetic domains  

International Nuclear Information System (INIS)

The precession of magnetization in 3He-B after excitation by a radio frequency field is found to be separated in an inhomogeneous stationary magnetic field into two homogenous magnetic domains. In one of the domains the magnetization processes spatially homogeneously whereas in the other it is at rest. The effect is due to spin supercurrents which carry the longitudinal magnetization to the region of strong magnetic fields and rotate the magnetization through an angle approximately 104 deg in the region of weaker magnetic fields. In this region the NMR frequency shift, which is of a dipole nature, compensates the magnetic field gradient. Results are presented of experimental studies of the formation and processes of relaxation of a dynamic domain with a spatially homogenous magnetizatoion precession

1985-06-01

56

Fundamental study on recovery of resources by magnetic separation using superconducting bulk magnet  

Energy Technology Data Exchange (ETDEWEB)

The process of polishing glass substrate is necessary for production of the liquid crystal, thus the substance which mainly consists of CeO{sub 2} (ceria) is used as a polishing agent. In this study, we aim to separate impurities selectively from waste slurry and recover ceria particles in order to reuse as a polishing agent. Waste fluid contains impurities such as ferrous particles originating from aggregating agent. We focused on the difference in magnetic property of each particle, and applied the high gradient magnetic separation with superconducting magnet which can separate not only ferromagnetic particle but also paramagnetic particle with relatively high magnetization. We controlled pH based on surface potential of ceria and ferrous particles in order to avoid the aggregation of the waste fluid. As the result of optimization of the conditions such as the geometry of filters, fluid flow rate and pH by calculation and experiment, the sufficient separation efficiency was obtained.

Okada, S., E-mail: okada@qb.see.eng.osaka-u.ac.jp [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mishima, F.; Akiyama, Y.; Nishijima, S. [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2011-11-15

57

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

1998-08-01

58

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

59

Highly Sensitive and Rapid Detection of Pseudomonas aeruginosa Based on Magnetic Enrichment and Magnetic Separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A method for highly sensitive and rapid detection of Pseudomonas aeruginosa, based on magnetic enrichment and magnetic separation, is described in this paper. The magnetic nanoparticles (MNPs) were applied to adsorb genome DNA after the sample was lysed. The DNA binding MNPs were directly subjected to polymerase chain reaction (PCR) to amplify gyrB specific sequence of Pseudomonas aeruginosa. The biotin labeled PCR products were detected by chemiluminescence when they ...

Yongjun Tang, Jun Zou

2013-01-01

60

Radiolysis and hydrolysis of magnetically assisted chemical separation particles  

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-05-01

 
 
 
 
61

Radiolysis and hydrolysis of magnetically assisted chemical separation particles  

International Nuclear Information System (INIS)

The magnetically assisted chemical separation (MACS) process is designed to separate transuranic (TRU) elements out of high-level waste (HLW) or TRU waste. Magnetic microparticles (1--25 ?m) were coated with octyl (phenyl)N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP) and tested for removing TRU elements from acidic nitrate solutions. The particles were contacted with nitric acid solutions and Hanford plutonium finishing plant (PFP) simulant, irradiated with a high intensity 60Co ?-ray source, and evaluated for effectiveness in removing TRU elements from 2m HNO3 solutions. The resistance of the coatings and magnetic cores to radiolytic damage and hydrolytic degradation was investigated by irradiating samples of particles suspended in a variety of solutions with doses of up to 5 Mrad. Transmission electron microscopy (TEM), magnetic susceptibility measurements, and physical observations of the particles and suspension solutions were used to assess physical changes to the particles. Processes that affect the surface of the particles dramatically alter the binding sites for TRU in solution. Hydrolysis played a larger role than radiolysis in the degradation of the extraction capacity of the particles

1995-01-01

62

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

Science.gov (United States)

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

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

2013-12-01

63

"On-chip magnetic bead microarray using hydrodynamic focusing in a passive magnetic separator"  

DEFF Research Database (Denmark)

Implementing DNA and protein microarrays into lab-on-a-chip systems can be problematic since these are sensitive to heat and strong chemicals. Here, we describe the functionalization of a microchannel with two types of magnetic beads using hydrodynamic focusing combined with a passive magnetic separator with arrays of soft magnetic elements. The soft magnetic elements placed on both sides of the channel are magnetized by a relatively weak applied external magnetic field ( 21 mT) and provide magnetic field gradients attracting magnetic beads. Flows with two differently functionalized magnetic beads and a separating barrier flow are introduced simultaneously at the two channel sides and the centre of the microfluidic channel, respectively. On-chip experiments with fluorescence labeled beads demonstrate that the two types of beads are captured at each of the channel sidewalls. On-chip hybridization experiments show that the microfluidic systems can be functionalized with two sets of beads carrying different probes that selectively recognize a single base pair mismatch in target DNA. By switching the places of the two types of beads it is shown that the microsystem can be cleaned and functionalized repeatedly with different beads with no cross-talk between experiments.

Smistrup, Kristian; Kjeldsen, B.

2005-01-01

64

Flotation model of emulsion separation process using magnetic field  

International Nuclear Information System (INIS)

Magnetic separation of emulsions (MSE) is a perspective method of deemulsification during extractional processing of spent nuclear fuel. Using the data of previously conducted microscopic investigations a ''flotation'' model of MSE process is suggested, according to which interaction of ferromagnetic powder particles with emulsion drops is maily caused by flotation. On the basis of the model the method to calculate the optimum phase ratios and to evaluate possible efficiency of MSE process is suggested, which presupposes comparison of the main forces affecting the particles when the process is realized. It is shown that the calculation results coincide with experimental data as to MSE efficiency in the presence of surfactants

1987-01-01

65

Continuous separation of dry crushed coal at one ton per hour by high-gradient magnetic separation  

Science.gov (United States)

The separation of pyritic sulfur and ash forming minerals from dry crushed coal in a small, cyclic, high gradient magnetic separator over a range of each of the process parameters was tested. A band of operating conditions that affected reductions of the mineral contaminants and recoveries of the heating value comparable to gravimetric separations was defined. The procedures and results of an experimental program to extrapolate from the small, cyclic separations to continuous, pilot scale separation at a feed rate of 1 ton/h are described. The program testing magnetic preparation of dry crushed coal has demonstrated that: (1) dry crushed coal in the size range of about 600 x 45 microns can be effectively cleaned by magnetic separation techniques; (2) product quality and heating value recovery by the high gradient magnetic process approaches that obtained by a laboratory gravimetric separation of the same size fraction; and (3) separations performed on size fractions from 600 to 45 microns at a feed rate of 1 ton/h in a continuous, industrial type high gradient magnetic separator equal those obtained in a cyclic laboratory separator.

Hise, E. C.; Wechsler, I.; Doulin, J. M.

1981-12-01

66

Passive magnetic separator integrated with microfluidic mixer: Demonstration of enhanced capture efficiency  

DEFF Research Database (Denmark)

In this paper, we present two results: (1) a new method for quantifying the efficiency of magnetic bead separators by magnetic measurements, and (2) a new idea for designing efficient magnetic bead separators. For microfluidic magnetic separators, a limiting factor for the capture of magnetic beads is the steep decrease of the magnetic force on the beads as a function of their distance to the magnetic structures. Our idea is to integrate the magnetic separator with a microfluidic mixer to ensure that all beads are brought close to the magnetic structures. We have fabricated a magnetic separator consisting of permalloy elements adjacent to a microfluidic channel. The performance of a system with an integrated surface structured (staggered herringbone) microfluidic mixer is compared to that of an equivalent system without the mixer. It is quantitatively demonstrated that the mixer significantly enhances the bead capture-and-release efficiency.

Lund-Olesen, Torsten; Bruus, Henrik

2006-01-01

67

On-chip Magnetic Separation and Cell Encapsulation in Droplets  

Science.gov (United States)

The demand for high-throughput single cell assays is gaining importance because of the heterogeneity of many cell suspensions, even after significant initial sorting. These suspensions may display cell-to-cell variability at the gene expression level that could impact single cell functional genomics, cancer, stem-cell research and drug screening. The on-chip monitoring of individual cells in an isolated environment could prevent cross-contamination, provide high recovery yield and ability to study biological traits at a single cell level These advantages of on-chip biological experiments contrast to conventional methods, which require bulk samples that provide only averaged information on cell metabolism. We report on a device that integrates microfluidic technology with a magnetic tweezers array to combine the functionality of separation and encapsulation of objects such as immunomagnetically labeled cells or magnetic beads into pico-liter droplets on the same chip. The ability to control the separation throughput that is independent of the hydrodynamic droplet generation rate allows the encapsulation efficiency to be optimized. The device can potentially be integrated with on-chip labeling and/or bio-detection to become a powerful single-cell analysis device.

Chen, A.; Byvank, T.; Bharde, A.; Miller, B. L.; Chalmers, J. J.; Sooryakumar, R.; Chang, W.-J.; Bashir, R.

2012-02-01

68

Thorium-uranium processing with gravity, magnetic and electrical separation in zarigan ore deposit  

International Nuclear Information System (INIS)

Because of low grade of thorium and uranium in the Zarigan mineral deposit, the pre-concentration operation prior to leaching is necessary. From X-ray diffraction analysis results, it was clear that this ore has large amount of other minerals such as Feldespat, Quartz, Hematite, Titanomagnetite, and rare earths. In this paper the thorium enhancement grade in Zarigan deposit by using gravity, magnetic and electrical separations methods is reported. The output of a Jaw crusher was ground to 85 micron by using ball mill. Then about 95% of SiO2 was separated by using shaking table separation. The heavy concentrate of shaking table was processed by a high intensity magnetic separator and then the magnetic concentrate separated by a low intensity magnetic separator. Finally, the non magnetic concentrate of low magnetic separator was processed with the electrical separation. The grades of thorium and uranium in the non magnetic concentrate of low magnetic separator were increased to 4000 and 5000 ppm, respectively where only 15% of the initial feed (ore) was transferred to this concentrate. Therefore, this resulted in a decrease of acid consumption in the leaching processes and the efficiency enhancement of the process. The pre-treatment circuit of this ore was designed as Jaw crusher/ball mill/shaking table/high-magnetic separator/low-magnetic separator/electrical separator, respectively.

2011-01-01

69

Tracing magnetic separators and their dependence on IMF clock angle in global magnetospheric simulations  

CERN Document Server

A new, efficient, and highly accurate method for tracing magnetic separators in global magnetospheric simulations with arbitrary clock angle is presented. The technique is to begin at a magnetic null and iteratively march along the separator by finding where four magnetic topologies meet on a spherical surface. The technique is verified using exact solutions for separators resulting from an analytic magnetic field model that superposes dipolar and uniform magnetic fields. Global resistive magnetohydrodynamic simulations are performed using the three-dimensional BATS-R-US code with a uniform resistivity, in eight distinct simulations with interplanetary magnetic field (IMF) clock angles ranging from 0 (parallel) to 180 degrees (anti-parallel). Magnetic nulls and separators are found in the simulations, and it is shown that separators traced here are accurate for any clock angle, unlike the last closed field line on the Sun-Earth line that fails for southward IMF. Trends in magnetic null locations and the struc...

Komar, C M; Dorelli, J C; Glocer, A; Kuznetsova, M M

2013-01-01

70

A superconducting magnetic separation system of ferromagnetic fine particles from a viscous fluid  

International Nuclear Information System (INIS)

A superconducting magnetic separation system has been developed to remove fine particles of martensitic transformed stainless steel (diameter: 1-10 ?m) from a viscous fluid. The magnetic filters were set in the superconducting magnet with large spaces between filters. The separation efficiency increased with the magnetic field due to the magnetic force to the particles being in the radial direction. The design concept of an HGMS is proposed. The separation efficiency was examined by changing the flow rate and magnetic field. The experimental results are used for the design of the system

2007-10-01

71

A study on a magnetic separation of radioactive corrosion products from NPP using permanent magnets  

International Nuclear Information System (INIS)

It is important to emphasize that the current trend to longer fuel cycles (18-24 months) has complicated the dilemma of finding optimum chemical condition for the primary coolant because of some problems such as increase of radioactive corrosion products, possibility of axial offset anomaly and so on. Radioactive corrosion products which are generated by the neutron activation of general corrosion products at a nuclear power plant are the major source of occupational radiation exposure. Generally, radioactive corrosion products exit in soluble and insoluble forms, and are removed by ion exchangers and purification filters. Most of the insoluble radioactive corrosion products have the characteristic of showing strong ferrimagnetism. Along with the new development and production of permanent magnets (rare earth magnets) which generate much stronger magnetic fields than conventional permanent magnets, a new type of magnetic filter is suggested that can efficiently separate corrosion products using rotation of permanent magnets. This new magnetic filter reveals good performance results in filtering magnetite, cobalt ferrite and nickel ferrite from aqueous coolant simulation

2004-04-01

72

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.

2011-11-01

73

Self-Assembled Magnetic Filter for Highly Efficient Immunomagnetic Separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have developed a compact and inexpensive microfluidic chip, the Self Assembled Magnetic filter, to efficiently remove magnetically tagged cells from suspension. The self-assembled magnetic filter consists of a microfluidic channel built directly above a self-assembled NdFeB magnet. Micrometer-sized grains of NdFeB assemble to form alternating magnetic dipoles, creating a magnetic field with a very strong magnitude B (from the material) and field gradient ?B (from the configuration) in th...

2011-01-01

74

Coal preparation using magnetic separation. Volume 5. Evaluation of magnetic coal desulfurization concepts. Final report  

Energy Technology Data Exchange (ETDEWEB)

Magnetic separator designs performed by the four contractors under RP980 were reviewed. A complete plant-conceptual design was developed, based on high-gradient magnetic separator (HGMS) designs proposed by Sala Magnetics, Inc., and the Magnetic Corporation of America (MCA). A design for a conventional heavy medium plant was also developed and costed to establish a point of comparison for the HGMS designs. The HGMS design provided by Sala is based on their commercial operating experience in the iron ore concentration industry and operation of a one-ton/hour continuous pilot plant, while the superconducting HGMS proposed by MCA represents a conceptual design based on bench-scale data. The three plants were designed to clean 2.64 million tons/year of feed and produce approximately 2.2 million tons/year of clean coal. Also, as a part of this project, a technical review of the Magnex process (current as of 7/78), as developed by Nedlog Technology Group/Hazen Research, Inc., was performed. Results indicate that the total capital requirement for the Sala and MCA plants was $107,100,000 and $93,500,000, respectively, while the conventional heavy medium plant was $27,400,000 (mid-1978 dollars). Thirty-year levelized operating costs were $25.61/ton and $23.40/ton (based on dry, clean coal) for the HGMS plants, and $7.70/ton for the heavy medium plant.

1980-07-01

75

Application of high temperature superconductors to high-gradient magnetic separation  

International Nuclear Information System (INIS)

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

1994-08-07

76

Surface structure of Si(111)-5 × 1-Au characterized by impact collision ion scattering spectroscopy  

Science.gov (United States)

Impact collision ion scattering spectroscopy (ICISS) has been used to characterize the Si(111)-5 × 1-Au surface, which was prepared by depositing about 0.4 monolayer (ML) of Au on a 7 × 7 Si(111) surface and annealing at 700°C. The experimental data clearly showed that the Au atoms causing the 5×1 structure were at least 0.7 Å above the outermost Si layer. A comparison of the ICISS results with computer simulations gave excellent agreement for a model of the Au-atom arrangement proposed by Le Lay that consisted of three domains with strings of Au atoms arranged along the [ overline110 ]-type azimuths in the Si(111) plane.

Huang, Judy H.; Stanley Williams, R.

1988-10-01

77

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

78

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

International Nuclear Information System (INIS)

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

2005-05-01

79

The electromagnetic design of a permanent magnet based separator  

CERN Document Server

The aim of this work was to design a permanent magnet based device that can selectively transport paramagnetic particles. Using specialised electromagnetic design software various arrangements of permanent magnets have been investigated. Each test geometry had to be constructively simple and able to produce highly non-uniform magnetic fields before being considered further in any more detail. The main parameter to indicate that the test geometry might be a suitable device has been ascribed to the ratio eta between the highest (ON) and lowest (OFF) magnetic fields that were measured. A linear arrangement of permanent magnets has been considered first. This device produced a ratio eta approx 2. Further, the cylindrical and the tubular arrangements may be considered as substantial improvements over the first geometry. The OFF magnetic fields have been substantially reduced by the method of magnetic shielding. Intensive research and modelling has been spent on addressing the problem of finding the optimal geometr...

Nedelcu, S

2002-01-01

80

Magnetic separation of particles and cells in ferrofluid flow through a straight microchannel using two offset magnets  

Science.gov (United States)

The separation of particles and cells is critical in many chemical and biological applications. This work presents a simple idea for utilizing a pair of permanent magnets to continuously separate diamagnetic particles and cells in ferrofluid flow through a straight microchannel. The first magnet is placed close to the microchannel for focusing the particle mixture to a single stream without the use of a sheath flow. The second magnet, which is offset from the first magnet and placed farther from the channel, is to displace the aligned particles to dissimilar flow paths for a continuous sorting. This idea is first demonstrated through the separation of 3 ?m- and 10 ?m-diameter polystyrene particles, where the effects of flow speed and magnet distance are both examined. The experimental data are found to fit well with the predictions of an analytical model. Furthermore, a continuous separation of live yeast cells from 10 ?m polystyrene particles is implemented in the same device.

Zeng, Jian; Deng, Yanxiang; Vedantam, Pallavi; Tzeng, Tzuen-Rong; Xuan, Xiangchun

2013-11-01

 
 
 
 
81

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

Science.gov (United States)

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

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

2010-11-01

82

Development of superconducting high gradient magnetic separation system for highly viscous fluid for practical use  

Energy Technology Data Exchange (ETDEWEB)

The HGMS system to remove the metallic wear debris was developed. The possibility of magnetic separation was indicated by simulation and experiment. The number of filters to obtain required separation rate was examined to design. In the industrial plants processing highly viscous fluid such as foods or industrial products, it is necessary to remove the metallic wear debris originating from pipe in manufacturing line which triggers quality loss. In this study, we developed a high gradient magnetic separation (HGMS) system which consists of superconducting magnet to remove the metallic wear debris. The magnetic separation experiment and the particle trajectory simulation were conducted with polyvinyl alcohol (PVA) as a model material (viscosity coefficient was 10 Pa s, which is 10,000 times higher than that in water). In order to develop a magnetic separation system for practical use, the particle trajectory simulation by using solenoidal superconducting magnet was conducted, and the possibility of the magnetic separation for removing ferromagnetic stainless steel (SUS) particles in highly viscous fluid of 10 Pa s was indicated. Based on the results, the number of filters to obtain required separation efficiency was examined to design the practical separation system.

Hayashi, S., E-mail: hayashi@qb.see.eng.osaka-u.ac.jp [Osaka Univ, 317 A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mishima, F.; Akiyama, Y.; Nishijima, S. [Osaka Univ, 317 A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2011-11-15

83

Use of a magnetic fluid-based process for coal separations  

Energy Technology Data Exchange (ETDEWEB)

The use of a laboratory-scale magnetic fluid-based separator for coal separations was examined. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two separation chambers, which were constructed of Plexiglas, were designed to fit between the pole pieces. A commercially available, water-based, ferromagnetic fluid was used as the separating medium. The separating density was changed by varying the current intensity of the electromagnetic coil. Both batch and continuous separations were made using 0.59 x 0.50-mm and 0.18 x 0.15-mm coal. The results are compared to those obtained using organic liquids. 20 refs., 7 figs., 1 tab.

Fofana, M.; Klima, M.S. [Pennsylvania State University, University Park, PA (United States). Mineral Processing Section

1997-02-01

84

Phase separation in degenerate magnetic semiconductor and high-temperature superconductors  

International Nuclear Information System (INIS)

This review on the electronic phase separation covers the following topics: model and heterophase self-trapping in the s-d model and t-J model, single charge carrier and ferron trapping, phase separation in degenerate magnetic semiconductors, phase transitions in EuSe and EuTe, impurity phase separation and in high-temperature superconductors. (WL)

1994-11-01

85

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

International Nuclear Information System (INIS)

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

2011-06-03

86

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.

2011-11-01

87

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

Science.gov (United States)

This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.0078silicone-MnZn ferrite coated sample (k2 =1.4058) in comparison with other samples.

Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zou, Chao; Yang, Jun; Dong, Juan

2013-12-01

88

Highly Sensitive and Rapid Detection of Pseudomonas aeruginosa Based on Magnetic Enrichment and Magnetic Separation  

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

89

Application of magnetic separation technology for the recovery of colemanite from plant tailings.  

Science.gov (United States)

In this study, colemanite was recovered from tailings produced by the Kestelek (Turkey) Processing Plant by magnetic separation. Magnetic susceptibility measurements revealed that colemanite is diamagnetic in character whereas gangue minerals are weakly paramagnetic, apparently due to the presence of the iron-bearing silicates such as smectite and, to a less extent, illite. Three-stage magnetic separation tests were performed on the size fractions coarser than 75 microm produced from the tailings (31.52% B(2)O(3)) using a high-intensity permanent magnetic separator. Under the test conditions a colemanite concentrate with a B(2)O(3) content of 43.74% at 95.06% recovery was shown to be produced from the tailings. The mineralogical composition of the tailings appears to allow the removal of gangue minerals by magnetic separation and hence the production of a concentrate of commercial grade. PMID:18927062

Alp, Ibrahim

2008-10-01

90

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

Science.gov (United States)

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

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

2013-08-30

91

Micelles, magnets and molecular mechanisms. Application to cage effects and isotope separation  

International Nuclear Information System (INIS)

This report reviews the general problem of cage reactions of radical pairs and diradicals. Based on Wigner's spin conservation rule and the expectation that only singlet radical pairs can undergo cage reactions, a natural consequence is the expectation that it should be possible to observe magnetic effects on the reactions of radical pairs. It is shown that two types of magnetic effects should be possible: (1) Effects due to the application of the magnetic field of a laboratory magnet during a reaction; (2) Effects due to the interactions of nuclear magnetic moments and electron magnetic moments. The experimental consequences of these magnetic effects are separation of isotopes based on differing nuclear magnetic moments and variation of the extent of cage reaction by variation of an applied field or by variation of nuclear magnetic moments. Striking experimental examples of these magnetic effects are provided by the photolysis of ketones in micellar solution and by the thermolysis of endoperoxides. (author)

1980-08-22

92

Separation of spin and orbital magnetizations in a samarium film  

Energy Technology Data Exchange (ETDEWEB)

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.

Stunault, A. E-mail: stunault@ill.fr; Soriano, S.; Gourieux, T.; Detlefs, C.; Dufour, C.; Dumesnil, K

2004-05-01

93

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

2004-05-01

94

Carbon nanotube clusters as universal bacterial adsorbents and magnetic separation agents.  

Science.gov (United States)

The magnetic susceptibility and high bacterial affinity of carbon nanotube (CNT) clusters highlight their great potential as a magnetic bio-separation agent. This article reports the CNT clusters' capability as "universal" bacterial adsorbents and magnetic separation agents by designing and testing a multiwalled carbon nanotube (MWNT) cluster-based process for bacterial capturing and separation. The reaction system consisted of large clusters of MWNTs for bacterial capture and an external magnet for bio-separation. The designed system was tested and optimized using Escherichia coli as a model bacterium, and further generalized by testing the process with other representative strains of both gram-positive and gram-negative bacteria. For all strains tested, bacterial adsorption to MWNT clusters occurred spontaneously, and the estimated MWNT clusters' adsorption capacities were nearly the same regardless of the types of strains. The bacteria-bound MWNT clusters also responded almost instantaneously to the magnetic field by a rare-earth magnet (0.68 Tesla), and completely separated from the bulk aqueous phase and retained in the system. The results clearly demonstrate their excellent potential as highly effective "universal" bacterial adsorbents for the spontaneous adsorption of any types of bacteria to the clusters and as paramagnetic complexes for the rapid and highly effective magnetic separations. PMID:19856390

Moon, Hyung-Mo; Kim, Jin-Woo

2010-01-01

95

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

Science.gov (United States)

New developments in powder metallurgical composites make soft magnetic composite (SMC) material interesting for application in electrical machines, when combined with new machine design rules and new production techniques. In order to establish these design rules, one must pay attention to electromagnetic loss characteristics of SMC material. In this work, five different series of iron based SMCs are produced and studied: (1) Pure iron powder with resin; (2) sintered iron based powders; (3) pure iron powder with additions of Zn-st and carbon; (4) iron based powder alloys (Fe,Nb,Si); (5) commercially available iron powder ``Somaloy.'' The specimens were shaped as rectangular rods and characterized on a miniature single sheet tester which was calibrated to Epstein. The measured energy losses are analyzed following the loss separation theory of Bertotti, in which the total energy loss is decomposed into hysteresis loss, classical Foucault loss, and an excess loss component.

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

2002-05-01

96

Method for Purifying and Recovering Silk Proteins Using Magnetic Affinity Separation.  

Science.gov (United States)

A method for the purification of recombinant silk proteins from a sample using magnetic affinity separation is described. The recombinant silk protein is expressed with an affinity tag which has a high binding affinity for an affinity ligand immobilized o...

C. Hoffmann K. Keller

2005-01-01

97

Parametric instabilities with well separated frequencies in magnetized plasmas  

International Nuclear Information System (INIS)

A nonlinear dispersion relation is derived for a homogeneous, magnetized plasma by the conventional 'ponderomotive force' method. By using this dispersion relation, various parametric instabilities (stimulated anomalous absorptions and scatterings) are discussed. The results are compared in detail with those obtained by other authors. In the validity region of this model the results derived by previous authors can be recovered. In addition to obtaining a few instabilities which have not been published in the literature, we also find that in general (i) the 'dipole approximation' can give the right results for the stimulated anomalous absorption problems and (ii) the ambient magnetic field may enhance the plasma stability. (author)

1981-01-01

98

Characteristics of the magnetic control of separable ferrous impurities contained in raw construction materials  

Directory of Open Access Journals (Sweden)

Full Text Available Currency of using the method of magnetic control of ferrous impurities for construction materials was noted. Especially it is important because of magnetic separators which are widely used for elimination of these impurities. There were shown the necessity of upgrading the present approach in order to realize the method of magnetic control. For example, it is necessary to take into account not only the rest of ferrous impurities (that is inevitable after limited numbers of operations but also a factor of involving sand particles. The concrete proposal how to develop the existing system of magnetic control of ferrous impurities in construction materials subjected to magnetic separation, is stated. The experimental-calculation model for such control is also shown. The main parameters of such model were estimated on the example of quartz sand and feldspar. The errors of standard methods of magnetic control were revealed for the first time.

A.V. Sandulyak

2013-04-01

99

On separation behavior of the devices with rotating plasma in crossed electric and magnetic fields  

International Nuclear Information System (INIS)

The results of the researches of cylindrical plasma, rotated in the crossed electric and magnetic fields are considered. Calculations and experiments have showed that at certain correlations of the electric and magnetic fields heating and separation of ions of different sorts is possible due to power supply of radial electric-field system.

2012-01-01

100

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

 
 
 
 
101

Admixture phase separation in degenerated magnetic semiconductors and high temperature superconductors  

International Nuclear Information System (INIS)

Phase separation in degenerated magnetic semiconductors and high-temperature ones is investigated. It is shown that antiferromagnetic crystal can be separated into regions with increased and reduced impurity concentration, among which the first one is ferromagnetic and second -antiferromagnetic. In other cases the region with increased impurity concentration can be antiferromagnetic with another type of ordering or otherwise - spin-liquid. 20 refs.;

1994-06-01

102

Effect of viscosity and temperature of hexafluoroacetone photolysis solutions on magnetic isotope separation efficiency  

International Nuclear Information System (INIS)

Dependence of magnetic isotope effect on viscosity and temperature of hexafluoroacetone solutions in perfluorooctane and perfluorinated dibutyl ether is established. It is shown that the obtained dependences of carbon isotope magnetic separation efficiency on temperature and viscosity of solutions have marked maximum for both solvents. Inconsistency of this maximum position for different solvents with respect to a viscosity value is attributed to the dependence of the magnetic isotope effect on hexafluoroacetone photolysis mechanism

1987-01-01

103

An evaluation of a laboratory wet-drum magnetic separator for micronized-magnetite recovery  

Energy Technology Data Exchange (ETDEWEB)

The US Department of Energy conducted bench-scale experiments to discover the performance of a conventional wet drum magnetic separator at separating micronized magnetite from fine coal. Relevant process variables included: feed solids concentration; separator feed rate; coal/magnetite ratio; and magnetite particle size. Calculation methods were developed to relate magnetite recovery and purity to operating conditions. 11 refs., 6 figs., 2 tabs.

Klima, M.S.; Killmeyer, R.P. [Pennsylvania State University, University Park, PA (United States). Mineral Processing Section

1995-12-31

104

Silane-modified magnetic beads: application to immunoglobulin G separation.  

Science.gov (United States)

The magnetic poly(2-hydroxyethyl methacrylate ethylene glycol dimethacrylate) [m-poly(HEMA-EGDMA)] beads (150-250-microm diameter in spherical form) were prepared by a radical suspension polymerization technique. The pseudo-specific ligand, reactive imidazole containing 3-(2-imidazoline-1-yl)propyl (triethoxysilane) (IMEO) was selected as a silanization agent. IMEO was covalently immobilized onto the magnetic beads. IMEO-immobilized m-poly(HEMA-EGDMA) beads were used for the affinity adsorption of immunoglobulin-G (IgG) from aqueous solutions and human plasma. To evaluate the degree of IMEO attachment, the m-poly(HEMA-EGDMA) beads were subjected to Si analysis by using flame atomizer atomic absorption spectrometer, and it was estimated as 36.6 mg IMEO/g of polymer. The nonspecific IgG adsorption onto the plain m-poly(HEMA-EGDMA) beads was very low (about 0.4 mg/g). Higher adsorption values (up to 55 mg/g) were obtained when the m-poly(HEMA-EGDMA)/IMEO beads were used from both aqueous solutions and human plasma. The maximum IgG adsorption on the m-poly(HEMA-EGDMA)-IMEO beads was observed at pH 7.0. The IgG molecules could be repeatedly adsorbed and desorbed with m-poly(HEMA-EGDMA)-IMEO beads without noticeable loss in the IgG adsorption capacity. The adsorption capacity from human plasma in magnetically stabilized fluidized bed decreased drastically from 78.9 to 19.6 mg/g with the increase of the flow rate from 0.2 to 3.5 mL/min. PMID:17824616

Oztürk, Nevra; Günay, M Emin; Akgöl, Sinan; Denizli, Adil

2007-01-01

105

Field emission resonances on junctions between Si(111)7 x 7 and Si(111)5 x 2-Au  

Energy Technology Data Exchange (ETDEWEB)

The image state derived field emission resonances (FER) are investigated on a Si(111)7 x 7 substrate which is partially covered by the quasi one-dimensional Si(111)5 x 2-Au structure. These states can be observed by dI/dV measurements of the unoccupied energy range if the STM is operated in a field emission mode. A shift of the FER peak positions on Si(111)7 x 7 patches vs. Si(111)5 x 2-Au patches is found which happens on a scale of one nanometer. The origin of that shift is attributed to work function differences caused by the different Fermi level pinning. The results are discussed in view of local work function changes determined by I(Z) spectroscopy across a (7 x 7)-(5 x 2-Au) junction.

Polei, Stefan; Barke, Ingo; Sell, Kristian; Oeynhausen, Viola von; Meiwes-Broer, Karl-Heinz [Institut fuer Physik, Universitaet Rostock, Universitaetsplatz 3, D-18051 Rostock (Germany)

2009-07-01

106

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

Science.gov (United States)

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

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

2007-06-01

107

High Temperature Superconducting Reciprocating Magnetic Separator Final Report  

Energy Technology Data Exchange (ETDEWEB)

In 2001, under DOE's Superconductivity Partnership Initiative (SPI), E. I. du Pont de Nemours & Co. (Dupont) was awarded a cost-share contract to build a fully functional full-scale model high temperature superconducting reciprocating magnet unit specifically designed for the koalin clay industry. After competitive bidding, American Superconductor (AMSC) was selected to provide the coil for the magnet. Dupont performed the statement of work until September 2004, when it stopped work, with the concurrence of DOE, due to lack of federal funds. DOE had paid all invoices to that point, and Dupont had provided all cost share. At this same time, Dupont determined that this program did not fit with its corporate strategies and notified DOE that it was not interesting in resuming the program when funding became available. AMSC expressed interest in assuming performance of the Agreement to Dupont and DOE, and in March 2005, this project was transferred to AMSC by DOE amendment to the original contract and Novation Agreement between AMSC and Dupont. Design drawings and some hardware components and subassemblies were transferred to AMSC. However, no funding was obligated by DOE and AMSC never performed work on the project. This report contains a summary of the work performed by Dupont up to the September 04 timeframe.

James F. Maguire

2008-06-05

108

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

109

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

Science.gov (United States)

We investigate a non-locality of Moss-Okninski transformation (MOT) used to separate positive and negative energy states in the 3+1 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 ?c = ?/mc. In the plane transverse to the magnetic field, the non-locality depends both on magnetic radius L = (?/eB)1/2 and ?c. The non-locality of MOT for the 2+1 Dirac equation is also considered.

Rusin, Tomasz M.; Zawadzki, Wlodek

2012-08-01

110

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

111

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

International Nuclear Information System (INIS)

We investigate a non-locality of Moss–Okninski transformation (MOT) used to separate positive and negative energy states in the 3+1 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 ?c = ?/mc. In the plane transverse to the magnetic field, the non-locality depends both on magnetic radius L = (?/eB)1/2 and ?c. The non-locality of MOT for the 2+1 Dirac equation is also considered. (paper)

2012-08-10

112

Metalizing reduction and magnetic separation of vanadium titano-magnetite based on hot briquetting  

Science.gov (United States)

To achieve high efficiency utilization of Panzhihua vanadium titano-magnetite, a new process of metalizing reduction and magnetic separation based on hot briquetting is proposed, and factors that affect the cold strength of the hot-briquetting products and the efficiency of reduction and magnetic separation are successively investigated through laboratory experiments. The relevant mechanisms are elucidated on the basis of microstructural observations. Experimental results show that the optimal process parameters for hot briquetting include a hot briquetting temperature of 475°C, a carbon ratio of 1.2, ore and coal particle sizes of less than 74 ?m. Additionally, with respect to metalizing reduction and magnetic separation, the rational parameters include a magnetic field intensity of 50 mT, a reduction temperature of 1350°C, a reduction time of 60 min, and a carbon ratio of 1.2. Under these above conditions, the crushing strength of the hot-briquetting agglomerates is 1480 N, and the recovery ratios of iron, vanadium, and titanium are as high as 91.19%, 61.82%, and 85.31%, respectively. The new process of metalizing reduction and magnetic separation based on hot briquetting demonstrates the evident technological advantages of high efficiency separation of iron from other valuable elements in the vanadium titano-magnetite.

Chen, Shuang-yin; Chu, Man-sheng

2014-03-01

113

High gradient magnetic separation versus expanded bed adsorption: a first principle comparison.  

Science.gov (United States)

A robust new adsorptive separation technique specifically designed for direct product capture from crude bioprocess feedstreams is introduced and compared with the current bench mark technique, expanded bed adsorption. The method employs product adsorption onto sub-micron sized non-porous superparamagnetic supports followed by rapid separation of the 'loaded' adsorbents from the feedstock using high gradient magnetic separation technology. For the recovery of Savinase from a cell-free Bacillus clausii fermentation liquor using bacitracin-linked adsorbents, the integrated magnetic separation system exhibited substantially enhanced productivity over expanded bed adsorption when operated at processing velocities greater than 48 m h(-1). Use of the bacitracin-linked magnetic supports for a single cycle of batch adsorption and subsequent capture by high gradient magnetic separation at a processing rate of 12 m h(-1) resulted in a 2.2-fold higher productivity relative to expanded bed adsorption, while an increase in adsorbent collection rate to 72 m h(-1) raised the productivity to 10.7 times that of expanded bed adsorption. When the number of batch adsorption cycles was then increased to three, significant drops in both magnetic adsorbent consumption (3.6 fold) and filter volume required (1.3 fold) could be achieved at the expense of a reduction in productivity from 10.7 to 4.4 times that of expanded bed adsorption. PMID:11787803

Hubbuch, J J; Matthiesen, D B; Hobley, T J; Thomas, O R

2001-01-01

114

The performance and on-line monitoring of dense medium wet drum magnetic separators  

Energy Technology Data Exchange (ETDEWEB)

Experimental work using a wet drum magnetic separator has shown this piece of equipment to be extremely robust. Magnetic separators tend to be overlooked by both maintenance and metallurgical personnel. They appear to work with no attention other than the occasional shot of grease. In surveys conducted it was commonly observed that the separator physical settings were not as they should have been. Poor performance of wet drum magnetic separators commonly observed in industrial situations is usually due to their being operated well outside their design envelope. This paper briefly describes the pilot plant experimental programme and considers the reasons for the considerably inferior results obtained in the real world. The findings have clearly shown that a device to continually monitor magnetite losses in magnetic separator tailings, either installed permanently as part of the plant instrumentation, or temporarily as a trouble shooting device, would be of considerable value to producers and have motivated the development of the Magnetics Loss Monitor (MLM). The operation of this monitor and the first field trials are also described. (author). 17 figs., 10 refs.

Rayner, J.G.; Holtham, P.N.; Napier-Munn, T.J. [Queensland Univ., Brisbane, QLD (Australia). Julius Kruttschnitt Mineral Research Centre

1995-12-31

115

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

Science.gov (United States)

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

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

2014-07-01

116

Experimental study of separation of magnetization precession in 3He-B into two magnetic domains  

International Nuclear Information System (INIS)

The precession of the nuclear spin magnetization in 3He-B after excitation by an rf pulse in a nonuniform static magnetic field is found to split into two homogeneous magnetic domains. The spatial precession of the magnetization is uniform in one domain and at rest in the other. The splitting is caused by spin supercurrents which carry the longitudinal magnetization toward higher magnetic fields and tip (rotate) the magnetization through an angle approx.1040 in the region where the field is weaker. The NMR frequency shift (which is of dipole origin) compensates the magnetic field gradient in the weak-field region. Experimental results are reported concerning the formation and relaxation of the dynamic domain in which the magnetization precesses uniformly in space

1985-06-01

117

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

118

Magnetic-fluid separations of coal using a modified Frantz electromagnet  

Energy Technology Data Exchange (ETDEWEB)

The paper describes a magnetohydrostatic technique for conducting float-sink separations of coal using magnetic fluids. A Frantz electromagnet was modified with new pole pieces to hold a batch separation cell. Finite element analysis of the magnetic field distribution showed close agreement between the simulated and measured value. The float-sink results indicated that magnetic fluid separation using the Frantz electromagnet was effective for coal separations for particle sizes greater than 100 mesh. The yield data agreed well with those obtained using organic liquids and zinc bromide solutions. However, the ash data showed differences especially at the lower relative densities where near density material was significant. The discrepancies were explained by the misplacement of coal particles resulting from the slightly non-uniform magnetic field gradient. Measurements indicated that the fluid viscosity was approximately 2 cP for the range of conditions tested. Overall, the results suggest that the design of the pole pieces is very critical to obtain quantitative washability data (yield, ash, and sulfur data) in coal separations, which would match the results obtained with organic liquids or salt solutions. The design is particularly critical when separating coal at low-relative densities where significant quantities of near density material are present. 29 refs., 12 figs., 3 tabs.

Fofana, M.; Klima, M.S. [Pennsylvania State University, University Park, PA (United States). Mineral Processing Section

1997-12-01

119

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

Science.gov (United States)

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

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

2014-01-01

120

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate a non-locality of Moss-Okninski transformation (MOT) used to separate positive and negative energy states in the 3+1 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...

Rusin, Tomasz M.; Zawadzki, Wlodek

2011-01-01

 
 
 
 
121

Complex dynamics of self-generated magnetic clusters in phase-separated perovskites  

International Nuclear Information System (INIS)

The linear and non-linear AC magnetic susceptibilities of the perovskite La1-xSrxCoO3, with 0.15=< x=<0.30, are presented. It is observed that, for x<0.20, a freezing temperature is defined by AC magnetic susceptibility, pointing to a glassy behaviour whose origin is the phase separation of ferromagnetic metallic-like clusters embedded in an insulating matrix. At this temperature, the non-linear magnetic susceptibility shows critical divergence, similar to spin-glasses, although the width of the diverging peak does not compare well with canonical spin-glasses

2005-07-01

122

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

123

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

Science.gov (United States)

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

Ahedo, Eduardo; Merino, Mario

2012-08-01

124

First nuclear magnetic resonance measurements of on-line separated isotopes  

International Nuclear Information System (INIS)

Nuclear magnetic resonance of on-line oriented nuclei is reported for the first time, the authors report on the cases of mass separated /sup 106/In, /sup 108/In and /sup 104/Ag and show that unique spin assignments become possible together with high precision moments values

1986-01-01

125

A 4.4 K refrigeration system for an industrial magnetic separator  

International Nuclear Information System (INIS)

This paper describes a small capacity refrigerator for an industrial superconducting magnetic separator and the small capacity turbine specially developed for the plant. The refrigeration capacity is 25 W at about 4.4 K without the need for liquid nitrogen precooling. Descriptions are included of the refrigeration cycle and of the major plant components. (author)

1976-05-14

126

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

Science.gov (United States)

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

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

2010-11-01

127

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

International Nuclear Information System (INIS)

Less biodegradable dissolved organic matters in water as typified by humic substances are known as precursors of carcinogenic trihalomethanes, and are removed about 60% by current advanced water treatments. However, further increase of the removal ratio is demand. In this study, magnetic mesoporous carbon (MMPC), which can adsorb the substances physically and be efficiently collected by using superconducting high gradient magnetic separation (HGMS), has been synthesized with coconut-shell-based activated carbon and ferric nitrate solution by the gas activation method. The MMPC has the maximum magnetization value of 30.7 emu/g and an adsorption ability of 87% to 10 mg/L humic acid in a short time. The standard MMPC having a magnetization of 6.43 emu/g was able to be separated at magnetic field of 2 T. Used MMPC regained the adsorption ability to 93.1% by N2 reactivation heat treatment. These results show promise for application of current water treatments by superconducting HGMS, which is suitable for high-speed water treatment without secondary wastes.

2010-11-01

128

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

International Nuclear Information System (INIS)

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

1998-01-01

129

High gradient magnetic separation of upconverting lanthanide nanophosphors based on their intrinsic paramagnetism  

Energy Technology Data Exchange (ETDEWEB)

Photon upconverting nanophosphors (UCNPs) have the unique luminescent property of converting low-energy infrared light into visible emission which can be widely utilized in nanoreporter and imaging applications. For the use as reporters in these applications, the UCNPs must undergo a series of surface modification and bioconjugation reactions. Efficient purification methods are required to remove the excess reagents and biomolecules from the nanophosphor solution after each step to yield highly responsive reporters for sensitive bioanalytical assays. However, as the particle size of the UCNPs approaches the size of biomolecules, the handling of these reporters becomes cumbersome with traditional purification methods such as centrifugation. Here we introduce a novel approach for purification of bioconjugated 32-nm NaYF{sub 4}: Yb{sup 3+}, Er{sup 3+}-nanophosphors from excess unbound biomolecules utilizing high gradient magnetic separation (HGMS)-system constructed from permanent super magnets which produce magnetic gradients in a magnetizable steel wool matrix amplifying the magnetic field. The non-magnetic biomolecules flowed straight through the magnetized HGMS-column while the UCNPs were eluted only after the magnetic field was removed. In the UCNPs the luminescent centers, i.e., lanthanide-ion dopants are responsible for the strong upconversion luminescence, but in addition they are also paramagnetic. In this study we have shown that the presence of these weakly paramagnetic luminescent lanthanides actually also enables the use of HGMS to capture the UCNPs without incorporating additional optically inactive magnetic core into them.

Arppe, Riikka, E-mail: riikka.arppe@utu.fi; Salovaara, Oskari; Mattsson, Leena; Lahtinen, Satu; Valta, Timo; Riuttamaeki, Terhi; Soukka, Tero [University of Turku, Department of Biotechnology (Finland)

2013-09-15

130

Wide aperture multipole magnets of the kinematic separator COMBAS. Analyzing multipole magnets M1 and M8 with compensation for higher order aberrations  

International Nuclear Information System (INIS)

The high-resolving large aperture kinematic separator COMBAS has been created and commissioned. The magneto-optical structure of separator is based on the strong focusing principle. The separator consists of eight wide aperture multipole magnets M1-M8. The first and the last magnets, M1 and M8, contain power quadrupole and octupole components in their field distributions. The presence of these components allowed one to intensify focusing without quadrupoles, minimize spherical aberrations and compensate for chromatic effects. Three-component magnetic measurements of the multipole magnets M1 and M8 have been performed, These measurements let both compile 3D-maps of the magnetic fields and analyze the magnet manufacturing quality. The 3D-maps of the magnetic field are supposed to be used for the particle trajectory simulations along the separator

1999-01-01

131

Measurement of the adhesion force between particles for high gradient magnetic separation of pneumatic conveyed powder products  

Energy Technology Data Exchange (ETDEWEB)

In the industrial plants such as foods, medicines or industrial materials, there are big amount of issues on contamination by metallic wear debris originated from pipes of manufacturing lines. In this study, we developed a high gradient magnetic separation system (HGMS) under the dry process by using superconducting magnet to remove the ferromagnetic particles. One of the major problems of dry HGMS systems is, however, the blockage of magnetic filter caused by particle coagulation or deposition. In order to actualize the magnetic separation without blockage, we introduced pneumatic conveyance system as a new method to feed the powder. It is important to increase the drag force acting on the sufficiently dispersed particles, which require strong magnetic fields. To generate the strong magnetic fields, HGMS technique was examined which consists of a magnetic filter and a superconducting solenoid magnet. As a result of the magnetic separation experiment, it was shown that the separation efficiency changes due to the difference of the cohesive property of the particles. On the basis of the result, the adhesion force which acts between the ferromagnetic particles and the medium particles used for the magnetic separation was measured by Atomic Force Microscope (AFM), and cohesion of particles was studied from the aspect of interparticle interaction. We assessed a suitable flow velocity for magnetic separation according to the cohesive property of each particle based on the result.

Senkawa, K., E-mail: senkawa@qb.see.eng.osaka-u.ac.jp [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nakai, Y.; Mishima, F.; Akiyama, Y.; Nishijima, S. [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2011-11-15

132

Measurement of the adhesion force between particles for high gradient magnetic separation of pneumatic conveyed powder products  

International Nuclear Information System (INIS)

In the industrial plants such as foods, medicines or industrial materials, there are big amount of issues on contamination by metallic wear debris originated from pipes of manufacturing lines. In this study, we developed a high gradient magnetic separation system (HGMS) under the dry process by using superconducting magnet to remove the ferromagnetic particles. One of the major problems of dry HGMS systems is, however, the blockage of magnetic filter caused by particle coagulation or deposition. In order to actualize the magnetic separation without blockage, we introduced pneumatic conveyance system as a new method to feed the powder. It is important to increase the drag force acting on the sufficiently dispersed particles, which require strong magnetic fields. To generate the strong magnetic fields, HGMS technique was examined which consists of a magnetic filter and a superconducting solenoid magnet. As a result of the magnetic separation experiment, it was shown that the separation efficiency changes due to the difference of the cohesive property of the particles. On the basis of the result, the adhesion force which acts between the ferromagnetic particles and the medium particles used for the magnetic separation was measured by Atomic Force Microscope (AFM), and cohesion of particles was studied from the aspect of interparticle interaction. We assessed a suitable flow velocity for magnetic separation according to the cohesive property of each particle based on the result.

2011-11-01

133

High gradient magnetic separation YBCO particles in a gas-fluidized bed  

Energy Technology Data Exchange (ETDEWEB)

In this paper, high gradient magnetic separation of copper-oxide superconducting particles in a gas-fluidized bed is studied experimentally. Particles over the size range 45-105 [mu]m exhibit classical behavior when fluidized with He gas at 77 K, whereas the more cohesive, smaller particles were difficult to fluidize. Separation experiments on a uniform mixture of tetragonal and orthorhombic phases have shown that 30 min of exposure to the field gradient is sufficient to equilibrate the superconductor concentration profile. In addition, the equilibrium separation data reveal that best separation is achieved at three times the minimum fluidization gas velocity U[sub mf]. This is consistent with the behavior of fine powders where the interparticle frictional forces are minimized at 3 U[sub mf]. Observed results are discussed in terms of a collective effect of Meissner and interparticle friction.

Labroo, S.; Ebrahimi, Y.; Park, J.Y.; Yeh, W.J. (Dept. of Chemical Engineering, Univ. of Idaho, Moscow, ID (United States))

1992-07-01

134

High gradient magnetic separation YBCO particles in a gas-fluidized bed  

International Nuclear Information System (INIS)

In this paper, high gradient magnetic separation of copper-oxide superconducting particles in a gas-fluidized bed is studied experimentally. Particles over the size range 45-105 ?m exhibit classical behavior when fluidized with He gas at 77 K, whereas the more cohesive, smaller particles were difficult to fluidize. Separation experiments on a uniform mixture of tetragonal and orthorhombic phases have shown that 30 min of exposure to the field gradient is sufficient to equilibrate the superconductor concentration profile. In addition, the equilibrium separation data reveal that best separation is achieved at three times the minimum fluidization gas velocity Umf. This is consistent with the behavior of fine powders where the interparticle frictional forces are minimized at 3 Umf. Observed results are discussed in terms of a collective effect of Meissner and interparticle friction

1992-07-01

135

Separate pulmonary artery and vein magnetic resonance angiography by use of an arterial spin labeling method.  

Science.gov (United States)

A separate pulmonary vein (PV) is difficult to depict with the commonly used bright-blood magnetic resonance angiography method. Until now, no study has described the depiction of peripheral PVs without the artery. Our purpose in this study was to develop an arterial spin labeling (ASL)-based magnetic resonance angiography sequence to depict the pulmonary artery (PA) and vein separately. We developed such a sequence by using two inversion recovery pulses. The first pulse was non-selective, and the second pulse was selective and was applied to the aorta and heart. All studies were conducted on a 1.5-T clinical magnetic resonance system with six different inversion times for seven healthy volunteers. For evaluation, we categorized the inversion times by using visual scoring. Then, we used the magnitude image to evaluate the PA, and we used the real image to evaluate the PV. For the PA, an inversion time of 300 ms had the lowest score (1.43), and the score changed with increasing times; an inversion time of 1,100 ms had the highest score (3.85). For the PV, an inversion time of 300 ms had the highest score (2.68), and the score decreased with increasing times. The results indicated that the PA and vein could be depicted separately by the use of an ASL-based magnetic resonance angiography method. The optimal inversion times for the PV and artery were 300 and 1,100 ms, respectively. PMID:24906451

Okuaki, Tomoyuki; Ishimoto, Tsuyoshi; Miyati, Tosiaki; Kobayashi, Satoshi; Ishihara, Masaru; Kawakami, Momoe; Ogino, Tetsuo; Van Cauteren, Marc

2014-07-01

136

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

137

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

2008-01-01

138

On-chip micro-electromagnets for magnetic-based bio-molecules separation  

Energy Technology Data Exchange (ETDEWEB)

This paper reports a comprehensive theoretical, finite element and measurement analysis of different designs of planar micro-electromagnets for bio-molecular manipulation. The magnetic field due to current flowing in complex shapes of current-carrying conductors have been calculated analytically, simulated using finite-element analysis (FEA), and measured using the superconducting quantum interference device technique (SQUID). A comparison of the theoretical and measured magnetic field strength and patterns is presented. The planar electromagnets have been fabricated using patterned Al 2 {mu}m thick. The aim of the study is to explore and optimize the geometrical and structural parameters of planar electromagnets that give rise to the highest magnetic fields and forces for magnetic micro-beads manipulation. Magnetic beads are often used in biochemical assays for separation of bio-molecules. Typical beads are 0.2-10 {mu}m in diameter and have superparamagnetic properties. Increasing the intensity of the magnetic field generated by a coil by injection a larger current is not the most suitable solution as the maximum current is limited by Joule heating. Consequently, in order to maximize the field for a given current, one should optimize the geometry of the coil, as this is an extremely significant factor in determining the magnetic field intensity in 2D planar designs. The theoretical and measured results of this work show that the meander micro-electromagnet with mesh-shaped winding profile produces the strongest magnetic field (about 2.7 {mu}T for a current intensity of 6 mA) compared with other meander designs, such as the serpentine and rosette-shaped ones. The magnetic fields of these three types of meander-shaped micro-electromagnets were compared theoretically with that produced by a spiral micro-electromagnet whose technological realization is more complicated and costly due to the fact that it requires an additional insulation layer with a contact window and a second patterned metal layer as a via. Nevertheless, the spiral design produces a much stronger magnetic field up to five times larger than that of the mesh-shaped micro-electromagnet for the same current and electromagnet area. The measured results strongly agree with these conclusions resulted from the theoretical analysis. The results presented in this paper provide a solid and useful basis for the design of a micro-fluidic bio-molecule separation and detection system using magnetic fields and magnetic beads.

Ramadan, Qasem E-mail: qasem@pmail.ntu.edu.sg; Samper, Victor; Poenar, Daniel; Yu Chen

2004-10-01

139

Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation  

International Nuclear Information System (INIS)

A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (Kd) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles

1995-01-01

140

Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation  

Energy Technology Data Exchange (ETDEWEB)

A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K{sub d}) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles.

Bauer, C.B.; Rogers, R.D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Chemistry; Nunez, L.; Ziemer, M.D.; Pleune, T.T.; Vandegrift, G.F. [Argonne National Lab., IL (United States)

1995-11-01

 
 
 
 
141

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

1986-06-01

142

Magnetic antibody immunoassay (MAIA) - a new improved separation technique in radioimmunoassay  

International Nuclear Information System (INIS)

Following a short description of the principle of radioimmunoassay and immunoradiometric assay, the special difficulties connected with the separation steps are discussed. Centrifugation is subject to inaccuracies and both time-consuming and technically complicated. Moreover it involves the risk of microbial or radioactive contamination. A new solid-phase procedure is presented using magnetizable particles as solid phase which are for instance bonded with the antibody. Separation is effected by collection of the magnetizable particles and the attached antibodies using a permanent magnet and subsequent decanting of the supernatant. The method is explained using two examples (cortisol, digoxin). (ZDE)

1981-01-01

143

Magnetic separation of malaria-infected red blood cells in various developmental stages.  

Science.gov (United States)

Malaria is a serious disease that threatens the public health, especially in developing countries. Various methods have been developed to separate malaria-infected red blood cells (i-RBCs) from blood samples for clinical diagnosis and biological and epidemiological research. In this study, we propose a simple and label-free method for separating not only late-stage but also early-stage i-RBCs on the basis of their paramagnetic characteristics due to the malaria byproduct, hemozoin, by using a magnetic field gradient. A polydimethylsiloxane (PDMS) microfluidic channel was fabricated and integrated with a ferromagnetic wire fixed on a glass slide. To evaluate the performance of the microfluidic device containing the ferromagnetic wire, lateral displacement of NaNO2-treated RBCs, which also have paramagnetic characteristics, was observed at various flow rates. The results showed excellent agreement with theoretically predicted values. The same device was applied to separate i-RBCs. Late-stage i-RBCs (trophozoites and schizonts), which contain optically visible black dots, were separated with a recovery rate of approximately 98.3%. In addition, using an optimal flow rate, early-stage (ring-stage) i-RBCs, which had been difficult to separate because of their low paramagnetic characteristics, were successfully separated with a recovery rate of 73%. The present technique, using permanent magnets and ferromagnetic wire in a microchannel, can effectively separate i-RBCs in various developmental stages so that it could provide a potential tool for studying the invasion mechanism of the malarial parasite, as well as performing antimalarial drug assays. PMID:23815099

Nam, Jeonghun; Huang, Hui; Lim, Hyunjung; Lim, Chaeseung; Shin, Sehyun

2013-08-01

144

Optical Fingerprints of Si Honeycomb Chains and Atomic Gold Wires on the Si(111)-(5×2)-Au Surface  

Science.gov (United States)

The intensively studied Si(111)-(5×2)-Au surface is reexamined using reflectance anisotropy spectroscopy and density functional theory simulations. We identify distinctive spectral features relating directly to local structural motifs such as Si honeycomb chains and atomic gold wires that are commonly found on Au-reconstructed vicinal Si(111) surfaces. Optical signatures of chain dimerization, responsible for the observed (×2) periodicity, are identified. The optical response, together with STM simulations and first-principles total-energy calculations, exclude the new structure proposed very recently based on the reflection high-energy electron diffraction technique analysis of Abukawa and Nishigaya [Phys. Rev. Lett. 110, 036102 (2013)] and provide strong support for the Si honeycomb chain with the triple Au chain model of Erwin et al. [Phys. Rev. B 80, 155409 (2009)]. This is a promising approach for screening possible models of complex anisotropic surface structures.

Hogan, Conor; Ferraro, Elena; McAlinden, Niall; McGilp, John F.

2013-08-01

145

Local electronic structure and surface potential of atomic chains on Si(111)5 x 2-Au  

Energy Technology Data Exchange (ETDEWEB)

Quasi one-dimensional surface reconstructions are formed by various metals adsorbed on flat or vicinal Si(111). On Si(111)5 x 2-Au the spatially resolved density of states is measured by scanning tunneling spectroscopy. Spectral features are assigned to particular structural elements based on a recently proposed model. In this contribution two key elements are discussed: (1) the Si honeycomb chain channel (HCC) with locally graphitic structure which is found on many chain systems, and (2) Si adatoms with an average coverage of 0.25 atom per 5 x 2 unit cell leading to pronounced bright protrusions in STM images. While the latter result in local electron doping, the HCC give rise to a pronounced corrugation of the surface potential perpendicular to the chains. These variations manifest themselves in energy modulations of unoccupied, image-state derived electron states.

Barke, Ingo; Polei, Stefan; Sell, Kristian; Oeynhausen, Viola von; Meiwes-Broer, Karl-Heinz [Universitaet Rostock, Institut fuer Physik, Universitaetsplatz 3, D-18051 Rostock (Germany)

2011-07-01

146

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, 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 ...

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

2010-01-01

147

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation; Caracterizacao da granalha de aco recuperada do residuo de rochas ornamentais por separacao magnetica  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is characterization of steel grit recovered from ornamental rock waste by magnetic separation. The magnetic separation was realized in three steps: first, using a high intensity wet magnetic separator, which used only the remaining magnetic field of equipment. In the second step, the magnetic material obtained in the first phase was subjected to a new manual magnetic separation using rare earth magnets. In a third step, magnetic material obtained with rare earth magnets was subjected to manual magnetic separation using ferrite magnets. After the magnetic separation, the material was sent to characterization which was obtained by chemical analysis, scanning electron microscopy, X-ray diffraction and size analysis. The size analysis showed that the concentrate range from 0,5 to 563,67 {mu}m with 4 wt.% over 100 {mu}m and content metallic iron of 93 wt%. (author)

Junca, E.; Telles, V.B.; Rodrigues, G.F.; Oliveira, J.R. de; Tenorio, J.A.S., E-mail: eduardojunca@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais; Instituto Federal de Ciencia e Tecnologia do Espirito Santo (IFES), Vitoria, ES (Brazil)

2010-07-01

148

The global mapping of the lunar crustal magnetic field using new external internal separation field techniques  

International Nuclear Information System (INIS)

Complete text of publication follows. In this work we report a global mapping of vector lunar magnetic field based on new method of separation of internal and external fields. The magnetic measurements collected during the lifetime of Lunar Prospector (LP) extended mission during 1999 were strongly disturbed by the solar wind, a period which coincided with a maximum of the 23 cycle activity. The multi scale wavelength external fields were analyzed using spherical harmonic transform. The external field determined by inversion was then removed from each magnetic field component for each half orbit. To map the vector magnetic crustal anomalies, all LP magnetometer data collected at low altitudes in the three different lunar environments: (1) geomagnetic tail (2) solar wind (3) geomagnetic sheath, were processed using this new approach. The results obtained using this method allow us to derive at, variable spacecraft altitudes, a high spatial resolution crustal magnetic anomalies fields. This global mapping clearly shows that the strongest anomalies are located antipodal to large young basins. Moreover, high albedo features, such as Reiner Gamma or Descartes Formations, are associated with similar magnitude anomalies. The modeling of some of these strongest anomalies shows a clustered paleomagnetic pole positions within a radius of 35 degrees centered at (30S, 225E). This result strengthens the hypothesis of a now extincted paleo lunar dynamo that may have probably magnetized rocks of lunar crust.

2009-08-23

149

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

Science.gov (United States)

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

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

2013-10-01

150

Cesium separation from contaminated milk using magnetic particles containing crystalline silicotitantes  

International Nuclear Information System (INIS)

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

2000-11-01

151

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

Science.gov (United States)

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. PMID:21071144

Yang, Huifen; Jing, Lili; Zhang, Baogang

2011-01-30

152

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

International Nuclear Information System (INIS)

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 deg. 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.

2011-01-30

153

Separation of uranium from nitric and hydrochloric acid solutions with extractant-coated magnetic microparticles  

International Nuclear Information System (INIS)

The magnetically assisted chemical separation (MACS) process utilizes selective magnetic microparticle composites to separate dissolved metals from solution. In this study, MACS particles were coated with neutral and acidic organophosphorus extractants,octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO), and bis(2-ethyl-hexyl)phosphoric acid (D2EHPA or HDEHP) and were evaluated for the separation of uranyl ions from nitric- and hydrochloric-acid solutions. The results suggest that a synergistic interaction between the particle surface and solvent coating may explain why the particles display, in some cases, orders of magnitude of higher partitioning coefficients than are estimated from solvent-extraction measurements. Particles coated with TBP and those coated with a combination of TOPO and D2EHPA displayed the most desirable characteristics for removing uranium from dilute acid environments typical of contaminated groundwater. Uranium separation from moderate to highly acidic waste streams typical of Department of Energy (DOE) nuclear wastes is best accomplished using particles coated with a combination of CMPO and TBP

2000-01-01

154

The gas-filled magnet: An isobar separator for accelerator mass spectrometry  

International Nuclear Information System (INIS)

The most difficult problem for accelerator mass spectrometry is the rejection of stable atomic isobars. The intensity of isobaric interference is expected to become a problem for 36Cl measurements with the use of new high-intensity ion sources. Although better chemical separation may be possible through improved sample preparation, the device expected to help most with this problem is the gas-filled magnet. We tested a gas-filled Enge split-pole spectrograph combined with a multi-plate gas ionization detector for the separation of 36S from 36Cl and obtained an isobar separation of about two orders of magnitude better than that possible with the detector alone. 10 refs., 3 figs., 1 tab

1988-11-07

155

Mineralogy and heavy metal leachability of magnetic fractions separated from some Chinese coal fly ashes  

International Nuclear Information System (INIS)

Magnetic fractions (MFs) in fly ashes from eight coal-burning power plants were extracted by magnetic separation procedure. Their mineralogy and potential leachability of heavy metals were analyzed using rock magnetism, X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX) and leaching procedures (toxicity characteristics leaching procedure by the United States Environmental Protection Agency, TCLP, and gastric juice simulation test, GJST). Results show that the MFs in the fly ashes range between 2.2 and 16.3 wt%, and are generally composed of magnetite, hematite, quartz and mullite. Thermomagnetic analysis and SEM/EDX indicate that the main magnetic carrier magnetite is substituted with small amounts of impure ions, and its structures are featured by rough, dendritic and granular iron spherules. The MFs are found to be rich in Fe, Mn, Cr, Cu, Cd and Pb. Compared with the non-magnetic fractions (NMFs), the MFs have about 5 times higher iron, and 1.6 times higher Mn, Cr, Cu and Cd concentrations. The TCLP test shows that the TCLP-extractable Cr, Cu, and Pb concentrations in the MFs are higher than those in the NMFs, while the TCLP-extractable Cd concentration in the MFs and NMFs is below the detection limit ( Cr > Pb > Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment.

2009-09-30

156

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

157

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

International Nuclear Information System (INIS)

Sn doped Fe3O4/SiO2 core-shell structures with the magnetic and photocatalytic properties have been successfully synthesized using Fe3O4 microspheres as the precursor. The morphology, phase and structure of the bifunctional products were investigated by X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and scanning electron microscopy. The effects of the amount and hydrolysis rate of tetraethyl orthosilicate on the preparation of the Fe3O4/SiO2 core-shell structures were investigated. Low concentration and slow hydrolysis rate of tetraethyl orthosilicate were useful to obtain the uniform silica coated Fe3O4. The magnetic measurements indicated that the Sn doped Fe3O4/SiO2 core-shell structures showed ferromagnetic property and the magnetic saturation value slightly decreased after coated the silica layer. The magnetic Sn doped Fe3O4/SiO2 core-shell structures exhibited good photocatalytic activity in the degradation of methyl orange and could be separated by applying an appropriate magnetic field.

2010-06-01

158

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

159

Effective antifouling using quorum-quenching acylase stabilized in magnetically-separable mesoporous silica.  

Science.gov (United States)

Highly effective antifouling was achieved by immobilizing and stabilizing an acylase, disrupting bacterial cell-to-cell communication, in the form of cross-linked enzymes in magnetically separable mesoporous silica. This so-called "quorum-quenching" acylase (AC) was adsorbed into spherical mesoporous silica (S-MPS) with magnetic nanoparticles (Mag-S-MPS), and further cross-linked for the preparation of nanoscale enzyme reactors of AC in Mag-S-MPS (NER-AC/Mag-S-MPS). NER-AC effectively stabilized the AC activity under rigorous shaking at 200 rpm for 1 month, while free and adsorbed AC lost more than 90% of their initial activities in the same condition within 1 and 10 days, respectively. When applied to the membrane filtration for advanced water treatment, NER-AC efficiently alleviated the biofilm maturation of Pseudomonas aeruginosa PAO1 on the membrane surface, thereby enhancing the filtration performance by preventing membrane fouling. Highly stable and magnetically separable NER-AC, as an effective and sustainable antifouling material, has a great potential to be used in the membrane filtration for water reclamation. PMID:24601563

Lee, Byoungsoo; Yeon, Kyung-Min; Shim, Jongmin; Kim, Sang-Ryoung; Lee, Chung-Hak; Lee, Jinwoo; Kim, Jungbae

2014-04-14

160

Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite  

Science.gov (United States)

The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite.

Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

2014-05-01

 
 
 
 
161

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-07

162

Solution for MEG inverse problem using Signal Space Separation and Magnetic Field Tomography  

Science.gov (United States)

Magnetic Field Tomography (MFT) is a source localization method for Magnetoencephalography (MEG), a non-invasive method to observe the brain activity. MFT just requires the source to be a linear combination of lead fields that describe the distribution of the sensitivity of each sensor, while other commonly used MEG source localization methods such as equivalent current dipole (ECD) fitting or the beamformer require some more inappropriate assumptions. However, less requirements on the source results in a huge amount of computational load in MFT. In this paper, the reduction of the computational load for MFT was achieved by considering the coefficients of multipolar expansion as the measurements of virtual sensors. These coefficients are obtained by performing Signal Space Separation (SSS) in which the exclusion of external magnetic field generated by the external sensor arrays is enabled. Based on our simulation, the calculation time was reduced from 6 hours to about 10 seconds preserving the source localization ability.

Kitahara, Tadashi; Honda, Satoshi

2011-06-01

163

Adaptive separation of regular and irregular magnetic activity for K indices  

Science.gov (United States)

A numerical-data adaptive-separation method is developed for the discrimination of quasi-regular magnetic variations from the irregular variations for the determination of the K indices. The method is based on a pattern comparison and discrimination technique using harmonic analyses and is more objective than the hand-scaling method. The method is tested on digital data from the Canadian magnetic observatories Victoria, Meanook, and Ottawa over a 4-month period. The data are at a 10-s sampling interval and encompass the full range of K values (0-9). The two methods were found to agree about 97 percent of the time, with most errors occurring during very irregular periods. This is comparable with values carefully determined by highly skilled observers. It is proposed that the method is suitable for use on a regular basis.

Walker, J. K.

1987-10-01

164

Radically different effects on materials by separated microwave electric and magnetic fields  

Energy Technology Data Exchange (ETDEWEB)

Using a 2.45 GHz wave-guided cavity, in a single mode TE{sub 103} excitation, we were able to physically locate compacted 5 mm pellets of samples separately at the H (magnetic) node (where the E field is nearly zero), or the E (electric) node (where H field is nearly zero). A preliminary survey of a variety of metals, (Cu, Fe, Co.) ceramics (ZnO, etc.), and composites, (WC-Co, ZnO-Co) showed remarkable differences in their heating behaviors. The results establish conclusively that the magnetic field interaction contributes greatly to microwave heating of common materials in a manner, previously neglected in most theories of microwave heating, albeit still to be understood. (orig.)

Cheng, J.; Roy, R.; Agrawal, D. [Pennsylvania State Univ., University Park (United States). Material Research Lab.

2002-02-01

165

Eddy current and total power loss separation in the iron-phosphate-polyepoxy soft magnetic composites  

International Nuclear Information System (INIS)

This work investigates the magnetic properties of iron-phosphate-polyepoxy soft magnetic composite materials. FTIR spectra, EDX analysis, distribution maps, X-ray diffraction pattern and density measurements show that the particles surface layer contains a thin layer of nanocrystalline/amorphous phosphate with high coverage of powders surface. In this paper, a formula for calculating the eddy current loss and total loss components by loss separation method is presented and finally the different parts of power losses are calculated. The results show that, the contribution of eddy current in the bulk material for single coating layer (kb = 0.18) is higher in comparison with double coating layer (kb = 0.09). Moreover, iron-phosphate-polyepoxy composites (P = 0.000004f2) have lower power loss in comparison with iron-phosphate composites (P = 0.00002f2).

2009-12-01

166

Classical functional Bethe ansatz for SL(N) separation of variables for the magnetic chain  

CERN Multimedia

The Functional Bethe Ansatz (FBA) proposed by Sklyanin is a method which gives separation variables for systems for which an R-matrix is known. Previously the FBA was only known for SL(2) and SL(3) (and associated) R-matrices. In this paper I advance Sklyanin's program by giving the FBA for certain systems with SL(N) R-matrices. This is achieved by constructing rational functions A(u) and B(u) of the matrix elements of T(u), so that, in the generic case, the zeros x.sub(i) of B(u) are the separation coordinates and the P.sub(i)=\\A(x.sub(i)) provide their conjugate momenta. The method is illustrated with the magnetic chain and the Gaudin model, and its wider applicability is discussed.

Scott, D R D

1994-01-01

167

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

2012-03-01

168

Quantitative microfluidic separation of DNA in self-assembled magnetic matrixes.  

Science.gov (United States)

We present an experimental study of the microfluidic electrophoresis of long DNA in self-assembling matrixes of magnetic bead columns. Results are presented for the rapid separation of lambda-phage, 2lambda-DNA, and bacteriophage T4 DNA, where separation resolutions greater than 2 between lambda and T4 are achieved in times as short as 150 s. The use of a computer-piloted flow control system and injection results in high reproducibility between separations. We compare the experimentally measured mobility and dispersion with an exactly solvable lattice Monte Carlo model. The theory predicts that the mean velocity scales linearly with the field, the band broadening scales with the inverse of the field, and the resolution is independent of the field for intermediate fields-all of which are in accord with the experimental results. Moreover, reasonable quantitative agreement is achieved for band broadening for longer DNA (2lambda and T4) when the average postengagement time is measured experimentally. This work demonstrates the possibility of achieving fast microfluidic separation of large DNA on a routine basis. PMID:15228353

Minc, Nicolas; Fütterer, Claus; Dorfman, Kevin D; Bancaud, Aurélien; Gosse, Charlie; Goubault, Cécile; Viovy, Jean-Louis

2004-07-01

169

Wide aperture multipole magnets of the kinematic separator COMBAS. Correcting pair of multipole magnets M3M4 (M5M6) with compensation for higher order aberrations  

International Nuclear Information System (INIS)

The high-resolving large aperture separator COMBAS has been created and commissioned. The magneto-optical structure of the separator is based on the strong focusing principle. The separator consists of eight wide aperture multipole magnets M1-M8. The magnets M1, M2, M7, M8 forming the 1st order optics together with some higher order optical corrections and M3-M6 being dedicated to higher order corrections of the chromatic and spherical aberrations at the intermediate and exit foci of the separator. The multipole correctors M3-M6 contain the dipolar, sextupole and octupole components in their magnetic field distributions. It was the use of the rectangular dipoles M3-M6 as carriers of sextupole and octupole field components that let achieve high values of the separator angular and momentum acceptances. Measurements of the magnetic field distributions in the median planes of the pairs of magnets M3M6 (M4M5) have been performed. These measurements allowed one to analyze the magnets manufacturing quality. Based on the analysis, shimming of pole pieces of the pair of magnets M3M6 have been done. Pole surface correcting coils for the magnets M4M5 have been foreseen to compensate for small deviations (within a few percents) of the 2nd and 3rd order field components from the design values, which are probable due to manufacturing errors in all the magnets M1-M8. The measured magnetic field distributions are supposed to be used for particle trajectory simulations throughout the entire separator

1999-01-01

170

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

171

Removal and recovery of phosphorus in wastewater by superconducting high gradient magnetic separation with ferromagnetic adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Prevention of eutrophication for semi-enclosed bays and ponds is serious and important challenge. In spite of the advanced wastewater treatment, typically 1 mg/L phosphorus is discharged into public water bodies from wastewater treatment plants. The total amount of the discharged water is so large that the further improvement of the removal efficiency of phosphorus in the discharged water is demanded. On the other hand, recently phosphorus has become increasingly recognized as the important strategic material due to the global food problem. Therefore, the recovery and recycling of phosphorus is also important issue. In this work, removal and recovery of phosphorus from treated wastewater by High Gradient Magnetic Separation (HGMS) with ferromagnetic zirconium ferrite adsorbent were studied. Phosphorus in the treated wastewater could be removed from 1.12 mg/L to 0.03 mg/L by the HGMS system with 500 mg/L zirconium ferrite adsorbent for 5 min in adsorption time. The magnetic separation speed achieved 1 m/s at 1 T which was necessary for practical use. We also confirmed that phosphorus could be desorbed from zirconium ferrite adsorbent by alkali treatment in a short time.

Ishiwata, T., E-mail: offspring0210@yahoo.co.j [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Miura, O.; Hosomi, K.; Shimizu, K.; Ito, D. [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Yoda, Y. [Bureau of Sewerage Tokyo Metropolitan Government, 2-8-1 Nishishinjyuku, Shinjyuku, Tokyo 163-8001 (Japan)

2010-11-01

172

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

International Nuclear Information System (INIS)

Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M 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*SEP"S"M 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*SEP"S"M 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

173

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

Energy Technology Data Exchange (ETDEWEB)

Magnetic particles (MAG*SEP{sup SM}) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP{sup SM} 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*SEP{sup SM} 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*SEP{sup SM} 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.

Nunez, L.; Buchholz, B.A.; Ziemer, M.; Dyrkacz, G.; Kaminski, M.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Atkins, K.J.; Bos, F.M.; Elder, G.R.; Swift, C.A.

1994-12-01

174

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

Science.gov (United States)

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. PMID:23541694

Wu, Jingwei; Su, Ping; Huang, Jun; Wang, Siming; Yang, Yi

2013-06-01

175

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

CERN Document Server

We investigate the vector-current correlation Pi_{mu nu} (VCC) in the presence of a strong external magnetic field (B_0 in the z direction) at low temperature (T0), i.e. the chiral-magnetic effect (CME). For this purpose, we employ the instanton-vacuum configuration at finite T with nonzero topological charge (Q_t>0). From the numerical calculations, it turns out that the longitudinal component of the connected VCC is liner in B_0 and shows a bump, representing a corresponding vector meson at |Q|=(300~400) MeV for T=0. The bump becomes enhanced as T increases and the bump position shifts to a lager |Q| value. In the limit of |Q|->0, the transverse component of the connected VCC disappears, whereas the longitudinal one remains finite and gets insensitive to B_0 with respect to T, due to diluting instanton contributions. Considering a simple collision geometry of HIC and some assumptions on the induced magnetic field and screening effect, we can estimate the charge separation (ChS) as a function of centrality u...

Nam, Seung-il

2010-01-01

176

Development of high gradient magnetic separation system for removing the metallic wear debris to be present in highly viscous fluid  

Energy Technology Data Exchange (ETDEWEB)

In the industrial plants processing highly viscous fluid such as foods or industrial materials, there is an issue of contamination by metallic wear debris originating from pipe of manufacturing line. It is necessary to remove the metallic wear debris in highly viscous fluid, since these debris causes quality loss. In this study, we developed a high gradient magnetic separation system by using superconducting magnet to remove the metallic wear debris. The particle trajectory simulation and the magnetic separation experiment were conducted with polyvinyl alcohol as a model material. As a result, ca. 100% and 92.2% of the separation efficiency was achieved respectively for the highly viscous fluid of 1 Pa s and 6 Pa s in viscosity, with 14 and 30 mesh magnetic filters.

Hayashi, S., E-mail: hayashi@qb.see.eng.osaka-u.ac.j [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mishima, F.; Akiyama, Y.; Nishijima, S. [Osaka University, A1 Bldg, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2010-11-01

177

Magnetization studies of phase separation in La$_{0.5}$Ca$_{0.5}$MnO$_{3}$  

CERN Multimedia

We present magnetization studies in a series of phase separated La$_{0.5}$Ca$%_{0.5}$MnO$_{3}$ samples, with different low temperature fractions of the ferromagnetic (FM) and charge ordered-antiferromagnetic (CO-AFM) phases. A particular experimental procedure probes the effect of the magnetic field applied while cooling the samples, which promotes FM fraction enlargement and enhances the melting of the CO phase. The response of the system depending on its magnetic field history indicates the existence of three different regimes in the phase separated state which develops below T$_{C}$. Our data allows us to identify the onset temperature below which the system becomes magnetic and structurally phase separated, and an onset field above which FM fraction enlargement occurs.

Freitas, R S; Levy, P; Parisi, F

2002-01-01

178

Development of superconducting magnets for LHC luminosity upgrade (2). Conceptual design of a large aperture dipole magnet for beam separation  

International Nuclear Information System (INIS)

Upgrade of the low-beta insertion system for the ATLAS and CMS experiments is proposed in the HL-LHC (High Luminosity LHC upgrade) project. It includes the final beam focusing quadrupoles, beam separation and recombination dipoles, and larger aperture matching section quadrupoles. KEK is in charge of conceptual design of the large aperture separation dipole D1. Latest design parameters are a main field of ?5 T at 1.9 K with Nb-Ti superconducting technology, a coil aperture of 160 mm, and a cos-theta 1-layer coil with LHC dipole cable. Since the new D1 is expected to be operated in very high-radiation environment, radiation resistance and cooling scheme are being carefully considered. The collaring-yoke structure is adopted to provide the mechanical support for the single layer Nb-Ti coil. We summarize the design study of this magnet, including (1) the very large iron saturation effect on field quality due to the large aperture and limited size of the iron yoke, (2) the stray field at the outer surface of the iron cryostat, (3) the stress management from room temperature assembly to final operation, and (4) the high-level of heat deposition in the coil due to radiation. (author)

2012-08-08

179

Function of the demagnetization factor in respect of a quasi-solid filtermatrix of a magnetic separator ?????????????? ??? ???????????? ??????????????? ????????????? ??????-??????? ?????????? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available The author presents the prospects for the use of a magnetic separator, equipped with a filter matrix, in the treatment of ceramic suspensions and minerals. Particles of ferromagnetic impurities are captured by matrix pores, when purified media is transmitted through the magnetized filter matrix. The particle capture efficiency depends on the level of the filter matrix magnetization. The intensity of demagnetization influences the filter matrix magnetization intensity. Unfortunately, many researchers frequently ignore the demagnetization factor of a filter matrix as a specific (granulated magnet.The effect of self-demagnetization is studied in terms of homogeneous (solid magnets. The effect of self-demagnetization means that poles emerge on the borders of magnetized “short” magnets. Thus, a strong inner demagnetization field emerges. The main parameter of this physical characteristic of sample-magnets is the coefficient of demagnetization, which relates the intensity of the demagnetization field and the magnetization intensity of a sample body. The author considers the relevant issue of influence of the demagnetization intensity on the average values of the magnetic permeability of porous (quasi-solid magnets, for example, a filter matrix. This dependence is relevant for the calculation of magnetic permeability values.??????????? ?????????? ?????? ? ???????????? ??????? ????????????????? ??????? N ?? ??????? ???????? ????????? ????????????? ???????? ?????????? (??????-??????. ????????? ???????? N ? ??????????? ?? ????????? ????? L ????? ?????????? ? ?? ???????? D . ????????, ??? ?????? N ????? ????????? ???????????????? ????? ? ????????? ?????????????? ???????? (? L/D . ????????????? ????? ????????? ???????? ??????????? ???????? ????????? ????????????? «????????» ??????-??????? ? ??? ????? ?????? ? ?? ??????????????? ?????????????????.

Sandulyak Anna Aleksandrovna

2013-07-01

180

Technical performance comparison of coal-pyrite flotation and high-gradient magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The Coal Preparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three coals - an Upper Freeport bed coal, a Lower Kittanning bed coal, and a Pittsburgh bed coal - to establish grade-recovery relationships characteristic of both processes. Representative portions of each coal sample were crushed to two top sizes - nominal minus 35 mesh and nominal minus 100 mesh - and subjected to conventional froth flotation. The froth product was then beneficiated by coal-pyrite flotation or HGMS to provide a direct technical comparison of the two processes. In addition, the raw coal samples were float-sink tested, and HGMS tests were run directly on the raw coal to assess the technological merit of single-stage HGMS. At minus 35 mesh, the size normally employed for coal flotation, both coal-pyrite flotation and HGMS effectively separated pyrite from coal, and the performance of the two processes was essentially the same. At a size of minus 100 mesh, however, the performance of HGMS exceeded that of coal-pyrite flotation. The separation effected by HGMS were more efficient at minus 100 mesh than at minus 35 mesh. On the other hand, it was concluded that either the effectiveness of coal-pyrite flotation decreases with diminishing top size, or the process has not been optimized to treat material finer than 35 mesh. Morever, as demonstrated by float-sink analyses, the separations achieved by all processing schemes considered were far from optimal.

Hucko, R.E.; Miller, K.J.

1980-11-01

 
 
 
 
181

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.

182

Pade-Froissart exact signal-noise separation in nuclear magnetic resonance spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

Nuclear magnetic resonance spectroscopy is one of the key methods for studying the structure of matter on different levels (sub-nuclear, nuclear, atomic, molecular, cellular, etc). Its overall success critically depends upon reliable mathematical analysis and interpretation of the studied data. This is especially aided by parametric signal processing with the ensuing data quantification, which can yield the abundance or concentrations of the constituents in the examined matter. The sought reliability of signal processing rests upon the possibility of an accurate solution of the quantification problem alongside the unambiguous separation of true from false information in the spectrally analysed data. We presently demonstrate that the fast Pade transform (FPT), as the unique ratio of two polynomials for a given Maclaurin series, can yield exact signal-noise separation for a synthesized free induction decay curve built from 25 molecules. This is achieved by using the concept of Froissart doublets or pole-zero cancellations. Unphysical/spurious (noise or noise-like) resonances have coincident or near-coincident poles and zeros. They possess either zero- or near-zero-valued amplitudes. Such spectral structures never converge due to their instability against even the smallest perturbations. By contrast, upon convergence of the FPT, physical/genuine resonances are identified by their persistent stability against external perturbations, such as signal truncation or addition of random noise, etc. In practice, the computation is carried out by gradually and systematically increasing the common degree of the Pade numerator and denominator polynomials in the diagonal FPT. As this degree changes, the reconstructed parameters and spectra fluctuate until stabilization occurs. The polynomial degree at which this full stabilization is achieved represents the sought exact number of resonances. An illustrative set of results is reported in this work to show the exact separation of genuine from spurious information by reliance upon Froissart doublets and stabilization of reconstructions. The FPT for optimal quantification of the physical constituents of the studied matter and the denoising Froissart filter for unequivocal signal-noise separation is expected to significantly aid nuclear magnetic resonance spectroscopy in achieving the most reliable data analysis and interpretation.

Belkic, Dzevad; Belkic, Karen, E-mail: Dzevad.Belkic@ki.se [Karolinska Institute, PO Box 260, S-171 76 Stockholm (Sweden)

2011-06-28

183

Research on high gradient magnetic separation of pneumatic conveyed powder products: Investigation from the viewpoint of interparticle interactions  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? We separated SUS particle from the mixture of alumina/silica and SUS particle. ? The high separation efficiencies were obtained both in two samples. ? The separation efficiency of the sample using alumina did not reach to 100%. ? The adhesion forces between particles were measured when changing the humidity. ? Based on these data, the conditions of the separation experiment were examined. -- Abstract: The separation and removal of the metallic debris originating from pipe of manufacturing line are required in the manufacturing process of the fine particle products. In this study, we develop a high gradient magnetic separation system (HGMS) under a dry process by using a superconducting magnet to remove ferromagnetic particles such as the material stainless steel (SUS). To avoid the obstruction of the separation part by aggregation of the processed material, we develop a magnetic separation system using a pneumatic conveying as a new transportation method of the particles. The magnetic separations were experimented under the same conditions on different days, but the results were different. The reason is considered to be the difference in adhesion force between the particles due to a change of humidity, we have measured the adhesion forces between the ferromagnetic particles and the paramagnetic medium particles using AFM (Atomic Force Microscope) while changing the humidity. As a result, the adhesion force between the particles increased with the increasing of humidity. Furthermore, we saw that the effect of relative humidity was larger in the adhesion force of alumina with larger cohesive property. Based on these results, an appropriate condition of the separation experiment was clarified. And a dehumidification mechanism was introduced.

Senkawa, Kohei, E-mail: senkawa@qb.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nakai, Yuki; Mishima, Fumihito [Graduate School of Engineering, Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Akiyama, Yoko, E-mail: yoko-ak@qb.see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nishijima, Shigehiro [Graduate School of Engineering, Osaka University, A1 Bldg., 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2013-01-15

184

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

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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.

Wan-Yuo Guo

2010-01-01

185

Heavy metal removal from soils using magnetic separation: 1. Laboratory experiments  

Energy Technology Data Exchange (ETDEWEB)

The removal of Cu, Zn, and Cd from a sandy soil was investigated using iron filings as an adsorbent, and subsequently recovering the iron filings by magnetic separation. The best treatment was obtained by using 5% iron filings and 3 h contact time between iron filings and the soil. The metal removal efficiency from soil extracts was evaluated, using MetPLATE trademark, a toxicity test that is specific for heavy metals, and the 48 h Ceriodaphnia dubia acute toxicity test. The toxicity removal was generally higher than 95% for Cu after a single treatment. With regard to Zn-spiked soil, the toxicity removal was 96.1%, 70.0%, and 49.6% after single treatment at the input concentration of 200 mg/kg, 400 mg/kg, and 800 mg Zn{sup 2+}/kg soil, respectively. After two or three successive treatments, more than 90% of the toxicity was removed for 400 mg/kg and 800 mg/kg Zn-spiked soils. In the case of Cd-spiked soil, a single treatment removed 51.1% of the toxicity from 200 mg/kg Cd-spiked soil extracts while more than 90% of the toxicity was removed after two or three treatments. Chemical analysis and a mass balance study were also carried out to investigate the Cu distribution in the soil fractions. The results indicate that, before treatment, a large portion of Cu was immobilized in the soil matrix. Following magnetic separation, Cu was removed from both the soil matrix and extracts and was indeed adsorbed and concentrated on the iron filings. The retrieval of Cu by iron filings was further examined by energy dispersive X-ray spectroscopy (EDS). (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Feng, Nan; Bitton, Gabriel; Yeager, Philip; Bonzongo, Jean-Claude [Laboratory of Environmental Microbiology and Toxicology, Department of Environmental Engineering Sciences, University of Florida, Gainesville (United States); Boularbah, Ali [Faculte des Sciences et Techniques Gueliz, Departement de Biologie, Universite Cadi Ayyad, Marrakech (Morocco)

2007-09-15

186

Removal of humic acid from aqueous solution by magnetically separable polyaniline: Adsorption behavior and mechanism.  

Science.gov (United States)

Magnetically separable polyaniline (Fe3O4@SiO2-PANI) was prepared by in situ chemical polymerization of aniline on the surface of silica-coated Fe3O4 nanoparticles, and characterized by FTIR spectroscopy, powder X-ray diffraction, elemental analysis, transmission electron microscopy, vibrating sample magnetometry and X-ray photoelectron spectroscopy. Characterization results showed that Fe3O4@SiO2-PANI with amino groups of 1.78mmol/g and the average diameter of 21.6nm are superparamagnetic. Adsorption behavior of Fe3O4@SiO2-PANI nanoparticles for humic acid (HA) was investigated by batch experiments and adsorption kinetic tests. HA adsorption amount on the adsorbent decreased with increasing solution pH and the presence of Ca(2+) resulted in the enhanced HA adsorption. HA adsorption on Fe3O4@SiO2-PANI could be well described by Langmuir model and the maximum adsorption amount of the adsorbent for HA at 25°C was 36.36mg/g. HA adsorption process on the adsorbent obey pseudo-second-order kinetics and the adsorption rates decrease with increasing initial HA concentration. The XPS analysis verified that HA adsorption over the adsorbent could be attributed to the surface complexation between the disassociated HA molecules and the protonated nitrogen of polyaniline on the adsorbent. HA loaded adsorbent could be magnetically separated and easily desorbed in 0.01mol/L NaOH solution. Regeneration tests indicated that Fe3O4@SiO2-PANI could be used repeatedly. PMID:24998066

Wang, Jiahong; Bi, Lijuan; Ji, Yanfen; Ma, Hongrui; Yin, Xiaolong

2014-09-15

187

Control of separated flow in a reflected shock interaction using a magnetically-accelerated surface discharge  

Science.gov (United States)

A numerical investigation was carried out to explore the effects of a magnetically-accelerated surface discharge on a separated, turbulent boundary layer in supersonic flow. The geometry and test conditions were chosen for comparison to experiments carried out at Princeton University. For those studies, a reflected shock interaction was created using a 14° shock generator acting on an incoming turbulent boundary layer with a Reynolds number based on momentum thickness of 1 × 104 and a freestream Mach number of 2.6. Three-dimensional, Reynolds-averaged, Navier-Stokes (RANS) calculations were carried out to simulate the experiments, using the US3D code developed at the University of Minnesota. The baseline code was modified to include a semi-empirical model of the surface discharge actuator, implemented through source terms in the momentum equation, vibrational energy equation, and total energy equation. The computational results for the baseline flow and several control cases were compared to experimental measurements of mean surface pressure. The level of discrepancy was typical of well-resolved RANS computations of three-dimensional, separated flows: qualitative agreement was obtained, and the general experimental trends were captured by the numerical model. Substantial three-dimensionality was observed even in the baseline flow, and significant changes in the flow topology were observed with the application of the actuator. Because of the highly three-dimensional nature of this shock interaction, the initial interpretation of the experiments may need to be revisited.

Atkinson, Michael D.; Poggie, Jonathan; Camberos, José A.

2012-12-01

188

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

International Nuclear Information System (INIS)

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.

2010-08-01

189

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

Science.gov (United States)

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

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

2010-08-01

190

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

191

Improved Peak Capacity for Capillary Electrophoretic Separations of Enzyme Inhibitors with Activity-Based Detection Using Magnetic Bead Microreactors  

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A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using NdFeB magnet(s) to immobilize alkaline phosphatase-coated superparamagnetic beads (2.8 ?m diameter) inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with the substrate, AttoPhos. Product generated in the enzyme...

Yan, Xiaoyan; Gilman, S. Douglass

2010-01-01

192

Analytical description of the coefficient of demagnetization for chains of cores of granulesin the filter matrix of a magnetic separator ????????????? ???????? ???????????? ??????????????? ????????????? ????????? ??????? ?????? ??????-??????? ?????????? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available Particle capturing efficiency inside the filter matrix of a magnetic separator used in the treatment of ceramic suspensions, minerals, condensates, other liquids and gas depends immediately on the intensity of its magnetization capacity. Chains of granules of a filter matrix represent effective magnetization channels. Demagnetization intensity influences the magnetization intensity of the whole filter matrix and its separate chains that are also considered as magnetization channels. The pattern of calculation of demagnetization factor N (coefficient of demagnetization for such channel magnets is of utmost academic interest, and this pattern is provided in this article. The author provides values for demagnetization factor N for quasi solid cores ofchains of granules having with various lengths L and diameters d (metal concentra-tion 0.78—0.99, if magnetized by the field having the intensity of ? =18–175 k?/m. It isproven that the values of N and ? L / d have an exponential relation.Earlier, the author identified that the values of N for the porous media having a cylindrical form depend on the ratio of the length of magnet L to its diameter D . It is proven that the values of N and those of ? L / D also have an exponential relation. Therefore, this reciprocal conformity of relations in respect of the demagnetization factor for samples of the granulated medium (consisting of chains of magnets-channels and for cores of magnets-channels (having different porosity values has confirmed the similarity of the demagnetization factor for magnets having substantial and high concentration of the ferromagnetic material. The analytical description (the formula of the coefficient of demagnetization of channel cores is provided in the article.?????? ?? ???????????? ????????? ? ??????????? ?????????????? ??????????????? ????, ? ??????? ???????????? ???????????-???????? ???????? ??????? ?????????????? ??????, ?????????? ??????? ??????? ??????? ?????? ? ?????????? ????????????????? ??????? N ????? ???????. ????????? ???????? N ??? ????????????? ????????? ??????? ????????? ???? L ? ????????? d , ? ????? ????????? ??? N ? ?????????? ? ???? ???????? ?????????????? ???????? ?????????? ? L / d , ??? ????????? ??????????? ? ??????????? ?????????? ??? ??????? ??????????????? ????? (????????? ?? ????? ???????.

Sandulyak Anna Aleksandrovna

2013-09-01

193

Separation of charge-order and magnetic QCPs in heavy fermions and high Tc cuprates  

Science.gov (United States)

The Fermi surface topology of high temperature superconductors inferred from magnetic quantum oscillation measurements provides clues for the origin of unconventional pairing thus previously not accessed by other spectroscopy techniques. While the overdoped regime of the high Tc phase diagram has a large Fermi surface consistent with bandstructure calculations, the underdoped regime of YBa2Cu2O6+x is found to be composed of small pockets. There is considerable debate as to whether the small observed ``pocket'' is hole-like or electron-like- whether the Fermi surface is best described by a t-J model or a conventional band folding picture- whether or not a Fermi liquid description applies- or- whether bilayer coupling splits the degeneracy of the observed pockets. We (myself and collaborators) have now collected an extensive body of experimental data that brings this debate to rest, but raises new questions about the nature of itinerant magnetism in underdoped high Tc cuprates. Quantum oscillation measurements are performed on multiple samples in magnetic fields extending to 85 T, temperatures between 30 mK (dilution fridge in dc fields to 45 T) and 18 K, over a range of hole dopings and with samples rotated in-situ about multiple axes with respect to the magnetic field. We perform a topographical map of the Fermi surface, enabling the in-plane shape of one of the pockets to be determined- imposing stringent constraints on the origin of the Fermi surface. While quantum oscillations measurements are consistent with a topological Fermi surface change associated with magnetism near optimal doping, they also point to a secondary instability deep within the underdoped regime beneath a high Tc superconducting sub-dome. An steep upturn in the quasiparticle effective mass is observed on underdoping, suggestive of a quantum critical point near x= 0.46 separating the metallic regime (composed of small pockets) from a more underdoped insulating charge-ordered regime (earlier reported in neutron scattering measurements). Our findings suggest the importance of two critical instabilities affecting the Fermi surface beneath the high Tc superconducting dome(s). While one of these has been proposed to provide the likely origin of unconventional pairing in the cuprates, the other can be an important factor in boosting transition temperatures. [4pt] This work is supported by the DoE BES grant ``Science in 100 T''. The author would like to thank collaborators S. E. Sebastian, C. H. Mielke, P. A. Goddard, M. M. Altarawneh, R. Liang, D. A. Bonn, W. N. Hardy and G. G. Lonzarich, and supporting staff at the National High Magnetic Field Laboratory (NHMFL). Quantum oscillation experiments are performed at the NHMFL, which is funded by the NSF with support from the DoE and State of Florida.

Harrison, Neil

2010-03-01

194

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

Science.gov (United States)

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

Cerff, Martin; Scholz, Alexander; Franzreb, Matthias; Batalha, Iris L; Roque, Ana Cecilia; Posten, Clemens

2013-05-20

195

Ultrasensitive detection of deltamethrin by immune magnetic nanoparticles separation coupled with surface plasmon resonance sensor.  

Science.gov (United States)

Small molecules or analytes present in trace level are difficult to be detected directly using conventional surface plasmon resonance (SPR) sensor, due to its small changes in the refractive index induced by the binding of these analytes on the sensor surface. In this paper, a new approach that combines SPR sensor technology with Fe3O4 magnetic nanoparticles (MNPs) assays is developed for directly detecting of deltamethrin in soybean. The Fe3O4 MNPs conjugated with antibodies specific to antigen serves as both labels for enhancing refractive index change due to the capture of target analyte, and "vehicles" for the rapid delivery of analyte from a sample solution to the sensor surface. Meanwhile, SPR direct detection format without Fe3O4 MNPs and gas chromatography (GC) analysis were conducted for detection of deltamethrin in soybean to demonstrate the amplification effect of Fe3O4 MNPs. A good linear relationship was obtained between SPR responses and deltamethrin concentrations over a range of 0.01-1ng/mL with the lowest measurable concentration of 0.01ng/mL. The results reveal that the detection sensitivity for deltamethrin was improved by 4 orders of magnitude compared with SPR direct detection format. The recovery of 95.5-119.8% was obtained in soybean. The excellent selectivity of the present biosensor is also confirmed by two kinds of pesticides (fenvalerate and atrazine) as controls. This magnetic separation and amplification strategy has great potential for detection of other small analytes in trace level concentration, with high selectivity and sensitivity by altering the target-analyte-capture agent labeled to the carboxyl-coated Fe3O4 MNPs. PMID:24747571

Liu, Xia; Li, Lei; Liu, You-Qian; Shi, Xing-Bo; Li, Wen-Jin; Yang, Yang; Mao, Lu-Gang

2014-09-15

196

Spin-charge separation in the t-J model: Magnetic and transport anomalies  

International Nuclear Information System (INIS)

A real spin-charge separation scheme is found based on a saddle-point state of the t-J model. In the one-dimensional (1D) case, such a saddle-point reproduces the correct asymptotic correlations at the strong-coupling fixed point of the model. In the two-dimensional (2D) case, the transverse gauge field confining spinon and holon is shown to be gapped at finite doping so that a spin-charge deconfinement is obtained for its first time in 2D. The gap in the gauge fluctuation disappears at half-filling limit, where a long-range antiferromagnetic order is recovered at zero temperature and spinons become confined. The most interesting features of spin dynamics and transport are exhibited at finite doping where exotic residual couplings between spin and charge degrees of freedom lead to systematic anomalies with regard to a Fermi-liquid system. In spin dynamics, a commensurate antiferromagnetic fluctuation with a small, doping-dependent energy scale is found, which is characterized in momentum space by a Gaussian peak at (?/a,?/a) with a doping-dependent width. This commensurate magnetic fluctuation contributes a non-Korringa behavior for the NMR spin-lattice relaxation rate. There also exists a characteristic temperature scale below thich a pseudogap behavior appears in the spin dynamics. Furthermore, an incommensurate magnetic fluctuation is also obtained at a finite energy regime. In the transport, a strong-range phase intereference leads to an effective holon Lagrangian which can give rise to a series of interesting phenomena including linear-T resistivity and a T"2 Hall angle. We discuss the striking similarities of these theoretical features with those found in the high-T_c cuprates and give a consistent picture for the latter. Electronic properties like Fermi surface and superconducting pairing in this framework are also discussed

1995-07-01

197

Magnetic isotope and magnetic field effects on chemical reactions. Sunlight and soap for the efficient separation of 13C and 12C isotopes  

International Nuclear Information System (INIS)

Photolysis of dibenzyl ketone (DBK) solution at room temperature yields 1,2-diphenylethane and carbon monoxide quantitatively. Results of the study of this reaction, using light and ordinary mercury lamps as excitation sources, show that (1) a measurable, but small, 12C/13C isotope separation occurs in homogeneous (benzene) solution; (2) the efficiency of the separation is greatly enhanced in soap solution relative to homogeneous solution; (3) the carbonyl carbon of DBK is specifically and exponentially enriched as photolysis proceeds; (4) an external magnetic field significantly influences the efficiency of the isotopic separation. Mass spectroscopic and NMR analyses of the recovered DBK confirm these conclusions. 2 figures

1978-11-08

198

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

Energy Technology Data Exchange (ETDEWEB)

A novel method is described for the preparation of superparamagnetic mesoporous maghemite (gamma-Fe{sub 2}O{sub 3})/silica (SiO{sub 2}) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe{sub 3}O{sub 4}) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe{sub 3}O{sub 4} to gamma-Fe{sub 2}O{sub 3} by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 deg. C feature spherical shape and uniform particle size (d{sub particle}=1.72 mum), high saturation magnetization (M{sub s}=17.22 emu/g), superparamagnetism (M{sub r}/M{sub s}=0.023), high surface area (S{sub BET}=240 m{sup 2}/g), and mesoporosity (d{sub pore}=6.62 nm). The composite microsphere consists of interlocked amorphous SiO{sub 2} nanoparticles, in which cubic gamma-Fe{sub 2}O{sub 3} nanocrystals are homogeneously dispersed and thermally stable against gamma- to alpha-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 A{sub 260}/A{sub 280} values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

Chen Feng; Shi Ruobing; Xue Yun; Chen Lei [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China); Wan Qianhong, E-mail: qhwan@tju.edu.c [School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072 (China)

2010-08-15

199

Determination of nanoparticle force balance in an electrical magnetic separation system  

Directory of Open Access Journals (Sweden)

Full Text Available Analytical expressions for magnetic force gradient computation are given. FEM simulation of the matrix core in the working gap of a magnetic system is conducted. The magnetic force distribution is presented as a relative ratio. A force balance equation taking into account the magnetic force pattern is derived.

E.E. Volkanin

2014-04-01

200

Novel magnetically separable AgCl/iron oxide composites with enhanced photocatalytic activity driven by visible light  

International Nuclear Information System (INIS)

Highlights: •The AgCl/iron oxide composites were prepared by a chemical precipitation method. •The composites exhibited improved performances in the photodegradation of pollutants. •The visible light photocatalysts could be recycled easily by a magnet. -- Abstract: In this work, AgCl/iron oxide composites were synthesized by a simple chemical precipitation method and calcining process. The composition of the material and magnetic and optical properties of the composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating specimen magnetometer (VSM) techniques, which confirms the high crystalline and magnetic behavior of the composites. UV-vis diffuse reflectance spectral (DRS) studies showed that the AgCl/iron oxide composites were of much higher absorption in longer wavelength region compared to bare iron oxide. The AgCl/iron oxide composites showed better performance in the photodegradation of organic dyes Rhodamin B (RhB) under the fluorescent lamp irradiation, which is remarkably superior to the N-TiO2. The degradation of microcystin-LR (MC-LR) and phenol was also found to be good owing to its effective electron-hole separation at AgCl/iron oxide interface. The separation of AgCl/iron oxide composites from the treated water was achieved by an external magnetic field as ?-Fe2O3 exhibits enough magnetic power to facilitate the separation

2013-10-15

 
 
 
 
201

Novel magnetically separable AgCl/iron oxide composites with enhanced photocatalytic activity driven by visible light  

Energy Technology Data Exchange (ETDEWEB)

Highlights: •The AgCl/iron oxide composites were prepared by a chemical precipitation method. •The composites exhibited improved performances in the photodegradation of pollutants. •The visible light photocatalysts could be recycled easily by a magnet. -- Abstract: In this work, AgCl/iron oxide composites were synthesized by a simple chemical precipitation method and calcining process. The composition of the material and magnetic and optical properties of the composites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating specimen magnetometer (VSM) techniques, which confirms the high crystalline and magnetic behavior of the composites. UV-vis diffuse reflectance spectral (DRS) studies showed that the AgCl/iron oxide composites were of much higher absorption in longer wavelength region compared to bare iron oxide. The AgCl/iron oxide composites showed better performance in the photodegradation of organic dyes Rhodamin B (RhB) under the fluorescent lamp irradiation, which is remarkably superior to the N-TiO{sub 2}. The degradation of microcystin-LR (MC-LR) and phenol was also found to be good owing to its effective electron-hole separation at AgCl/iron oxide interface. The separation of AgCl/iron oxide composites from the treated water was achieved by an external magnetic field as ?-Fe{sub 2}O{sub 3} exhibits enough magnetic power to facilitate the separation.

Zhang, Ying; Zhang, Yanrong, E-mail: yanrong_zhang@hust.edu.cn; Tan, Jue

2013-10-15

202

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

Science.gov (United States)

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. PMID:22304328

Xue, Mianqiang; Li, Jia; Xu, Zhenming

2012-03-01

203

Magnetic separation and antibiotics selection enable enrichment of cells with ZFN/TALEN-induced mutations.  

Science.gov (United States)

The ability to enrich cells with targeted mutations greatly facilitates the process of using engineered nucleases, including zinc-finger nucleases and transcription activator-like effector nucleases, to construct such cells. We previously used surrogate reporters to enrich cells containing nuclease-induced mutations via flow cytometry. This method is, however, limited by the availability of flow cytometers. Furthermore, sorted cells occasionally fail to form colonies after exposure to a strong laser and hydrostatic pressure. Here we describe two different types of novel reporters that enable mutant cell enrichment without the use of flow cytometers. We designed reporters that express H-2K(k), a surface antigen, and the hygromycin resistance protein (Hygro(R)), respectively, when insertions or deletions are generated at the target sequences by the activity of engineered nucleases. After cotransfection of these reporters and the engineered nuclease-encoding plasmids, H-2K(k)- and Hygro(R)-expressing cells were isolated using magnetic separation and hygromycin treatment, respectively. We found that mutant cells were drastically enriched in the isolated cells, suggesting that these two reporters enable efficient enrichment of mutants. We propose that these two reporters will greatly facilitate the use of engineered nucleases in a wider range of biomedical research. PMID:23441197

Kim, Hyojin; Kim, Myung-Sun; Wee, Gabbine; Lee, Choong-il; Kim, Hyongbum; Kim, Jin-Soo

2013-01-01

204

Magnetic Field Control of Phase Separation Drives the Low Field Colossal Magnetoresistance in Mixed-valent Manganites  

CERN Document Server

The effect of low magnetic fields on the transport properties of phase separated manganites is studied. The different behavior obtained in samples of La0.5Ca0.5MnO3 related to the way in which the field is applied is consistent with a picture of changes in the metallic fraction induced by the magnetic field in a field cool cycle. Taking this fact, and using a simple model of conduction through a binary mixture, the interrelation between magnetoresistance, metallic fraction and percolation temperature is accounted for. A new physical coefficient relating magnetic field and metallic fraction emerges as the relevant parameter in the description of phase separated manganites.

Parisi, F; Polla, G; Vega, D

2001-01-01

205

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

Science.gov (United States)

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

Mayo, John Thomas

206

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

Science.gov (United States)

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

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

1978-01-01

207

Beta-NMR magnetic moment measurements using on-line mass separation and tilted-foil polarization  

International Nuclear Information System (INIS)

The methods of tilted foil nuclear polarization and on-line mass separation have for the first time been successfully applied to a Beta-Nuclear Magnetic Resonance (?-NMR) technique for measuring multipole moments of ?-unstable nuclei. The magnetic moment of 33Cl (T/sub 1/2/ = 2.51 s, I/sup ?/ = 3/2+), the mirror nucleus of 33S, was successfully measured using this arrangement. Following production by nuclear reaction, recoiling nuclei were mass separated by the Recoil Mass Spectrometer (RMS) after which they were polarized by passage through an array of tilted carbon foils, and implanted in a catcher. Nuclear polarization, monitored by detection of asymmetric ?-emission, was destroyed via resonant rf excitation to locate the nuclear magnetic resonance, which was marked by a disappearance of the decay anisotropy. Tests were performed with 12B (T/sub 1/2/ = 20.4 ms, I/sup ?/ = 1+) which were produced via the d(11B,12B)p reaction, and implanted in Au. The 33Cl nuclei were produced via the d(32S,33Cl)n reaction, and implanted in a NaCl single crystal. The ground-state magnetic moment of 33Cl, corrected for diamagnetism, is ? = +0.7523(16) ?/sub n/. The results for the mass 33 mirror shell pair are discussed in terms of three separate theoretical analyses of sd-shell mirror nuclei

1987-01-01

208

Baseline performance evaluation of micronized-magnetite recovery using conventional wet-drum and high-gradient magnetic separators  

Energy Technology Data Exchange (ETDEWEB)

In 1990 and 1991, a series of 97 laboratory-scale conventional wet-drum magnetic separation tests and 52 high-gradient magnetic separation tests were carried out at the Pittsburgh Energy Technology Center (PETC) of the US Department of Energy to investigate the performance of these processes in separating micronized magnetite ({minus}10{mu}m) from fine coal ({minus}600 {mu}m). This testing was part of a multiyear investigation into the evaluation and development of PETC's Micro-Mag Process, which involves the use of a micronized-magnetite and water mixture for cleaning fine coal in a cyclone, along with the subsequent recovery and reuse of the micronized magnetite. Some of the process variables studied included magnetite particle size, feed percent solids, magnetite-to-coal ratio, feed rate, and staging. The performance was analyzed in terms of magnetite recoveries and corresponding purities. The results demonstrated that recoveries of nearly 91% with purities of about 9 % magnetite were possible using a multistage (3 stages) conventional wet-drum recovery circuit. Under some conditions, recoveries approaching 99.9% with purities of nearly 95% were possible in a single pass through a high-gradient magnetic separator. This report provides the detailed operating and performance data for these series of tests.

Klima, M.S.; Killmeyer, R.P.

1992-01-01

209

Baseline performance evaluation of micronized-magnetite recovery using conventional wet-drum and high-gradient magnetic separators  

Energy Technology Data Exchange (ETDEWEB)

In 1990 and 1991, a series of 97 laboratory-scale conventional wet-drum magnetic separation tests and 52 high-gradient magnetic separation tests were carried out at the Pittsburgh Energy Technology Center (PETC) of the US Department of Energy to investigate the performance of these processes in separating micronized magnetite ({minus}10{mu}m) from fine coal ({minus}600 {mu}m). This testing was part of a multiyear investigation into the evaluation and development of PETC`s Micro-Mag Process, which involves the use of a micronized-magnetite and water mixture for cleaning fine coal in a cyclone, along with the subsequent recovery and reuse of the micronized magnetite. Some of the process variables studied included magnetite particle size, feed percent solids, magnetite-to-coal ratio, feed rate, and staging. The performance was analyzed in terms of magnetite recoveries and corresponding purities. The results demonstrated that recoveries of nearly 91% with purities of about 9@% magnetite were possible using a multistage (3 stages) conventional wet-drum recovery circuit. Under some conditions, recoveries approaching 99.9% with purities of nearly 95% were possible in a single pass through a high-gradient magnetic separator. This report provides the detailed operating and performance data for these series of tests.

Klima, M.S.; Killmeyer, R.P.

1992-08-01

210

Innovative methodology for comprehensive utilization of iron ore tailings: part 1. The recovery of iron from iron ore tailings using magnetic separation after magnetizing roasting.  

Science.gov (United States)

Iron ore tailings have become one kind of the most hazardous solid waste. In order to recycle iron in the tailings, we present a technique using magnetizing roasting process followed by magnetic separation. After analysis of chemical composition and crystalline phase, according to experimental mechanism, the effects of different parameters on recovery efficiency of iron were carried out. The optimum reaction parameters were proposed as the following: ratio of coal: iron ore tailings as 1:100, roasting at 800 degrees C for 30 min, and milling 15 min of roasted samples. With these optimum parameters, the grade of magnetic concentrate was 61.3% Fe and recovery rate of 88.2%. With this method, a great amount of iron can be reused. In addition, the microstructure and phase transformation of the process of magnetizing roasting were studied. PMID:19782467

Li, Chao; Sun, Henghu; Bai, Jing; Li, Longtu

2010-02-15

211

Interfacing Complementary Separation Techniques with Mass Spectrometry Utilizing Electrophoresis, Nanoparticles, and Functionalized Magnetic Beads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Capillary electrophoresis (CE) has during the last two decades become more robust and been able to separate neutral analytes without compromising the downstream detection. An interesting aspect in CE compared to more commonly used high-performance liquid chromatography is the orthogonal separation mechanism provided by CE. Compounds are separated based on charge and size with extremely high separation efficiencies. However, since mass spectrometry (MS) has become one of the most important ana...

Malmstro?m, David

2012-01-01

212

Fe3O4/PVIM-Ni(2+) Magnetic Composite Microspheres for Highly Specific Separation of Histidine-Rich Proteins.  

Science.gov (United States)

Integration of the advantages of immobilized metal-ion affinity chromatography (IMAC) and magnetic microspheres is considered as an ideal pathway for quick and convenient separation of his-tagged proteins, but rare reports concern the natural histidine-rich proteins. In this article, a novel route was presented to fabricate magnetic microspheres composed of a high-magnetic-response magnetic supraparticle (Fe3O4) core and a Ni(2+)-immobilized cross-linked polyvinyl imidazole (PVIM) shell via reflux-precipitation polymerization. The unique as-prepared Fe3O4/PVIM-Ni(2+) microspheres possessed uniform flower-like structure, high magnetic responsiveness, abundant binding sites, and very easy synthesis process. Taking advantage of the pure PVIM-Ni(2+) interface and high Ni(2+) loading amount, the microspheres exhibited remarkable selectivity, excellent sensitivity, large enrichment capacity, and high recyclability in immobilization and separation of his-tagged recombinant proteins. More interestingly, it was found that the Fe3O4/PVIM-Ni(2+) microspheres also showed excellent performance for removal of the natural histidine-rich bovine serum albumin (BSA) from the complex real sample of fetal bovine serum due to the exposed histidine residues. Considering their multiple merits, this new type of Fe3O4/PVIM-Ni(2+) nanomaterial displays great potential in enriching low-abundant his-tagged proteins or removing high-abundant histidine-rich natural proteins for proteomic analysis. PMID:24766586

Zhang, Yuting; Li, Dian; Yu, Meng; Ma, Wanfu; Guo, Jia; Wang, Changchun

2014-06-11

213

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

214

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

Science.gov (United States)

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. PMID:22796092

Hien, Thai Bao Dieu; Maeng, Joon-Ho; Lee, Byung Heon; Seong, Gi Hun; Choo, Jaebum; Lee, E K

2012-10-31

215

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

216

Magnetoresistance and magnetic susceptibility of phase-separated La-Pr-Ca manganites  

CERN Document Server

Electrical resistivity, magnetoresistance and magnetic susceptibility were measured for ceramic (La sub 1 sub - sub y Pr sub y) sub 0 sub . sub 7 Ca sub 0 sub . sub 3 MnO sub 3 samples (y 0.75 and 1) with different content of sup 1 sup 8 O isotope. All samples were paramagnetic insulators in the high-temperature range. Some of them became ferromagnetic (FM) metals at temperatures below 60-80 K. The high-temperature behaviour of the resistivity, magnetoresistance and magnetic susceptibility was practically identical for all samples in spite of the significant difference in their low-temperature properties. In particular, the magnetoresistance was proportional to the magnetic field squared and decreased approximately as 1/T sup 5 in a wide magnetic field and temperature range. The results were interpreted based on the concept of an inhomogeneous state with pronounced FM correlations in the paramagnetic phase.

Babushkina, N A; Kugel, K I; Rakhmanov, A L; Gorbenko, O Y; Kaul, A R

2003-01-01

217

Novel core-shell cerium(IV)-immobilized magnetic polymeric microspheres for selective enrichment and rapid separation of phosphopeptides.  

Science.gov (United States)

In this work, novel magnetic polymeric core-shell structured microspheres with immobilized Ce(IV), Fe3O4@SiO2@PVPA-Ce(IV), were designed rationally and synthesized successfully via a facile route for the first time. Magnetic Fe3O4@SiO2 microspheres were first prepared by directly coating a thin layer of silica onto Fe3O4 magnetic particles using a sol-gel method, a poly(vinylphosphonic acid) (PVPA) shell was then coated on the Fe3O4@SiO2 microspheres to form Fe3O4@SiO2@PVPA microspheres through a radical polymerization reaction, and finally Ce(IV) ions were robustly immobilized onto the Fe3O4@SiO2@PVPA microspheres through strong chelation between Ce(IV) ions and phosphate moieties in the PVPA. The applicability of the Fe3O4@SiO2@PVPA-Ce(IV) microspheres for selective enrichment and rapid separation of phosphopeptides from proteolytic digests of standard and real protein samples was investigated. The results demonstrated that the core-shell structured Fe3O4@SiO2@PVPA-Ce(IV) microspheres with abundant Ce(IV) affinity sites and excellent magnetic responsiveness can effectively purify phosphopeptides from complex biosamples for MS detection taking advantage of the rapid magnetic separation and the selective affinity between Ce(IV) ions and phosphate moieties of the phosphopeptides. Furthermore, they can be effectively recycled and show good reusability, and have better performance than commercial TiO2 beads and homemade Fe3O4@PMAA-Ce(IV) microspheres. Thus the Fe3O4@SiO2@PVPA-Ce(IV) microspheres can benefit greatly the mass spectrometric qualitative analysis of phosphopeptides in phosphoproteome research. PMID:24407680

Wang, Zhi-Gang; Cheng, Gong; Liu, Yan-Lin; Zhang, Ji-Lin; Sun, De-Hui; Ni, Jia-Zuan

2014-03-01

218

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: • Microwave reduction of a red mud. •Measurement of real and imaginary permittivity of red mud–lignite mixture. •Red mud was subjected to reductive roasting and magnetic separation processes. •The optimum concentrate contains 31.6% iron with a 69.3% metallization degree. •{sup 226}Ra, {sup 228}Ra, {sup 238}U, {sup 228}Th, {sup 232}Th, {sup 40}K were detected in the magnetic concentrate. -- Abstract: The present research work is focused on the development of an alternative microwave reductive roasting process of red mud using lignite (30.15 wt.% C{sub fix}), 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{sub 2}O{sub 3} ? Fe{sub 3}O{sub 4} ? 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, Michail, E-mail: msamouhos@metal.ntua.gr [School of Mining and Metallurgical Engineering, Laboratory of Metallurgy, National Technical University of Athens, 9, Iroon Polytechniou Street, 157 80 Zografou, Athens (Greece); Taxiarchou, Maria; Tsakiridis, Petros E. [School of Mining and Metallurgical Engineering, Laboratory of Metallurgy, National Technical University of Athens, 9, Iroon Polytechniou Street, 157 80 Zografou, Athens (Greece); Potiriadis, Konstantinos [Greek Atomic Energy Commission (GAEC), Patriarxou Grigoriou and Neapoleos, P.O. Box 60092, 15310 Agia Paraskevi, Athens (Greece)

2013-06-15

219

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

International Nuclear Information System (INIS)

Highlights: • Microwave reduction of a red mud. •Measurement of real and imaginary permittivity of red mud–lignite mixture. •Red mud was subjected to reductive roasting and magnetic separation processes. •The optimum concentrate contains 31.6% iron with a 69.3% metallization degree. •226Ra, 228Ra, 238U, 228Th, 232Th, 40K were detected in the magnetic concentrate. -- Abstract: 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 Fe2O3 ? Fe3O4 ? 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

2013-06-15

220

Electronic and magnetic phase separation in EuB6. Fluctuation spectroscopy and nonlinear transport  

International Nuclear Information System (INIS)

The main topics of this thesis are electrical, stationary, and time-resolved transport measurements on EuB6 as well as the further development of measuring methods and analysis procedures of the fluctuation spectroscopy. The first part of this thesis was dedicated to the further development of the already known measuring methods under application of a fast data-acquisition card. The second part deals with the electrical transport properties of EuB6 and the understanding of the coupling between charge and magnetic degrees of freedom. By means of resistance and nonlinear-transport measurements as well as fluctuation spectroscopy hypotheses of other scientists were systematically verified as well as new knowledge obtained. The magnetoresistance was studied as function of the temperature in small external magnetic fields between 1 mT and 700 mT. Measurements of the third harmonic resistance as function of the temperature show maxima at TMI and TC. Electrical-resistance fluctuations were measured without external magnetic field between 5 and 100 K as well in presence of a magnetic field between 18 K and 32 K. At constant temperature measurements of the spectral power density in external magnetic fields were performed in the temperature range from 18 K to 32 K. Highly resolving measurements of the thermal expansion coefficient showed a very strong coupling of the magnetic (polaronic) degrees of freedom to the crystal lattice.

2013-01-01

 
 
 
 
221

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

2013-11-01

222

Influence of magnetic nanoparticle size on the particle dispersion and phase separation in an ABA triblock copolymer.  

Science.gov (United States)

Oleic acid modified iron oxide nanoparticles (IONs) with different sizes were synthesized and mixed with styrene-butadiene-styrene block copolymer (SBS) with a lamellar structure. The octadecene segments on the oleic acid molecules have chemical affinity with the polybutadiene (PB) blocks, which makes IONs tend to be selectively confined in the microphase-separated PB domains. However, the dispersion state strongly depends on the ratio of the particle diameter (d) to the lamellar thickness (l) of the PB domains, which further changes the phase separation of SBS. When d/l ?0.5, most of IONs are concentrated in the middle of the PB layers at low particle loading. Upon increasing the particle loading, part of IONs contact each other to form long strings due to their strong magnetic interactions. Away from the strings, IONs are either selectively dispersed in the middle and at the interfaces of the PB domains, or randomly distributed at some regions in which the phase separation of SBS is suppressed. The phase separation of SBS transforms from the lamellar structure to a cylinder structure when the IONs loading is higher than 16.7 wt %. As d is comparable to l, IONs aggregate to form clusters of 100 to 300 nm in size, but within the clusters IONs are still selectively dispersed in the PB domains instead of forming macroscopic phase separation. It is interpreted in terms of the relatively small conformational entropy of the middle blocks of SBS; thus, incorporation of nanoparticles does not lead to much loss of conformational entropy. Although incorporation of IONs with d/l ?1 significantly increases the interfacial curvature and roughness, it has less influence on the phase separation structure of SBS due to the inhomogeneous dispersion. When d is larger than l, IONs are macroscopically separated from the SBS matrix to form clusters of hundreds of nanometers to several micrometers. More interestingly, the phase separation of SBS transforms from the lamellar structure to a two-phase co-continuous structure, probably due to the rearrangement of SBS molecules to cover the clusters with PB segments and the strong magnetic interaction exerting additional force on the SBS matrix during the evaporation of the solvent and the subsequent thermal annealing process. PMID:24479376

Wu, Jinrong; Li, Hui; Wu, Siduo; Huang, Guangsu; Xing, Wang; Tang, Maozhu; Fu, Qiang

2014-02-27

223

Methyl parathion imprinted polymer nanoshell coated on the magnetic nanocore for selective recognition and fast adsorption and separation in soils.  

Science.gov (United States)

Core-shell magnetic methyl parathion (MP) imprinted polymers (Fe3O4@MPIPs) were fabricated by a layer-by-layer self-assembly process. In order to take full advantage of the synergistic effect of hydrogen-binding interactions and ?-? accumulation between host and guest for molecular recognition, methacrylic acid and 4-vinyl pyridine were chosen as co-functional monomers and their optimal proportion were investigated. The core-shell and crystalline structure, morphology and magnetic properties of Fe3O4@MPIPs were characterized. The MP-imprinted nanoshell was almost uniform and about 100nm thick. Binding experiments demonstrated that Fe3O4@MPIPs possessed excellent binding properties, including high adsorption capacity and specific recognition, as well as fast adsorption kinetics and a fast phase separation rate. The equilibration adsorption capacity reached up to 9.1mg/g, which was 12 times higher than that of magnetic non-imprinted polymers, while adsorption reached equilibrium within 5min at a concentration of 0.2mmol/L. Furthermore, Fe3O4@MPIPs successfully provided selective separation and removal of MP in soils with a recovery and detection limit of 81.1-87.0% and 5.2ng/g, respectively. PMID:24275470

Xu, Shiying; Guo, Changjuan; Li, Yongxian; Yu, Zerong; Wei, Chaohai; Tang, Youwen

2014-01-15

224

Preparation of magnetic molecularly imprinted polymer for the separation of tetracycline antibiotics from egg and tissue samples.  

Science.gov (United States)

Magnetic molecularly imprinted polymers were prepared using hydrophobic Fe(3)O(4) magnetite as the magnetically susceptible component, oxytetracycline as template molecule, methacrylic acid as functional monomer, and styrene and divinylbenzene as polymeric matrix components. The polymers were applied to the separation of tetracycline antibiotics from egg and tissue samples. The extraction and clean-up procedures were carried out in a single step by blending and stirring the sample, extraction solvent and polymers. The analytes can be transferred from the sample matrix to the polymers directly or through the extraction solvent as medium. When the extraction was complete, the polymers adsorbing the analytes were easily separated from the sample matrix by an adscititious magnet. The analytes eluted from the polymers were determined by liquid chromatography-tandem mass spectrometry. The recoveries ranging from 72.8% to 96.5% were obtained with relative standard deviations in the range of 2.9-12.3%. The limit of detection was less than 0.2 ng g(-1). The feasibility of this method was validated by analysis of incurred egg and tissue samples, and the results were compared with those obtained by the classical method in which solvent extraction, centrifugation, and subsequent clean-up and concentration by solid-phase extraction were applied. The proposed method reduced the complicacy of classical method and improved the reliability of method. PMID:19268956

Chen, Ligang; Liu, Jun; Zeng, Qinglei; Wang, Hui; Yu, Aimin; Zhang, Hanqi; Ding, Lan

2009-05-01

225

Novel purification system for 6xHis-tagged proteins by magnetic affinity separation.  

Science.gov (United States)

We have developed a novel nickel-silica matrix for the generation of magnetic beads for metal-ion affinity chromatography. In contrast to magnetic Ni-NTA agarose beads, the novel particle type (SiMAC) consists of a magnetic core and a nickel-silica composite matrix with the nickel ions tightly integrated in the silica. This results in a much higher number of chelating groups compared with Ni-NTA agarose beads. With the SiMAC beads, greatly improved purification of histidine-tagged proteins from crude bacterial extracts was achieved. The yield was at least twice as high as with conventional materials, the method is faster, since the coupling step is omitted and there is no need for handling toxic Ni(2+) salts. PMID:12906907

Frenzel, André; Bergemann, Christian; Köhl, Gabi; Reinard, Thomas

2003-08-15

226

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

CERN Document Server

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

227

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

2003-05-01

228

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

229

Magnetic properties of cuprate superconductors based on a phase separation theory  

International Nuclear Information System (INIS)

There is a great debate concerning the hole of the inhomogeneities in high critical temperature superconductors (HTS). Several experiments indicate a possible electronic phase separation (PS). However, there is not a method to quantify how such transition occurs and how it develops. Here we show that the Cahn-Hilliard (CH) theory of phase separation provides a way to trace the phase separation process as a function of temperature. We connect these calculations with the Bogoliubov-deGennes (BdG) approach to an inhomogeneous superconductor and derive many HTS properties of the La2-xSrCuO4 (LSCO) system. The results yield: an onset of superconductivity that follows close the Nernst signal, the leading edge shift is close to the zero temperature average gap, and the superconducting phase is achieved by percolation. Our approach reproduces also the experimental measurements of the Hc2 field

2008-03-30

230

Electrostatic separation of ions in a bucket source with magnetic filter  

International Nuclear Information System (INIS)

We consider how ions with different temperatures may be selectively filtered by an electrostatic barrier which can exist in a magnetic multipole (Bucket) source equipped with a magnetic filter. The H+ ions have a greater temperature than the H2+ and H3+ species and so can cross the electrostatic barrier with less sttenuation than the molecular species. We suggest that low temperature impurity ions may also become trapped in the rear chamber of the source, thus leading to an improvement in source performance

1981-10-19

231

The GSI projectile fragment separator (FRS) - a versatile magnetic system for relativistic heavy ions  

International Nuclear Information System (INIS)

The projectile fragment separator FRS designed for research and applied studies with relativistic heavy ions was installed at GSI as a part of the new high-energy SIS/ESR accelerator facility. This high-resolution forward spectrometer has been successfully used in first atomic and nuclear physics experiments using neon, argon, krypton, xenon, and gold beams in the energy range from 500 to 2000 MeV/u. For the first time relativistic xenon and gold fragments have been isotopically separated. In this contribution we describe first experiments characterizing the performance of this spectrometer. (orig.)

1991-01-01

232

The GSI projectile fragment separator (FRS): a versatile magnetic system for relativistic heavy ions  

International Nuclear Information System (INIS)

The projectile fragment separator FRS designed for research and applied studies with relativistic heavy ions was installed at GSI as a part of the new high-energy SIS/ESR accelerator facility. This high-resolution forward spectrometer has been successfully used in first atomic and nuclear physics experiments using neon, argon, krypton, xenon, and gold beams in the energy range from 500 to 2000 MeV/u. For the first time relativistic xenon and gold fragments have been isotopically separated. In this contribution we describe first experiments characterizing the performance of the spectrometer. (orig.)

1992-08-01

233

Evidence for magnetic phase separation in colossal magnetoresistance compound EuB5.99C0.01  

Science.gov (United States)

EuB5.99C0.01 is a low-carrier density ferromagnet that is believed to be intrinsically inhomogeneous due to fluctuations of carbon content. In accordance with our previous studies, electric transport of EuB5.99C0.01 close above the temperature of the bulk ferromagnetic (FM) ordering is governed by magnetic polarons. Carbon-rich regions are incompatible with FM phase and therefore they act as spacers preventing magnetic polarons to link, to form FM clusters, and eventually to percolate and establish a (homogoneous) bulk FM state in this compound, what consequently causes additional (magneto) resistance increase. Below the temperature of the bulk FM ordering, carbon-rich regions give rise to helimagnetic domains, which are responsible for an additional scattering term in the electrical resistivity. Unfortunately, there has not been provided any direct evidence for magnetic phase separation in EuB5.99C0.01 yet. Here reported results of electrical, heat capacity, Hall resistivity and small-angle neutron scattering studies bring evidence for formation of mixed magnetic structure, and provide consistent support for the previously proposed scenario of the magnetoresistance enhancement in EuB5.99C0.01.

Batko, I.; Batkova, M.; Tran, V. H.; Keiderling, U.; Filipov, V. B.

2014-07-01

234

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

235

Process and device for the separation of fragments of liberated ferrous scrap from not liberated ferrous scrap fragments by means of a static magnet:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The invention relates to a process and device for the separation of fragments of liberated ferrous scrap from not liberated ferrous scrap fragments by means of a static magnet, wherein a mixture of said liberated ferrous and not liberated ferrous fragments is fed onto a continuous conveyor belt which is driven around drums and wherein said magnet is fixed in the drum distant from the feeding point, wherein a magnet is used which is preferably a dipole magnet having magnetic field lines in the...

Rem, P. C.; Berkhout, S. P. M.; Fraunholcz, O. N.

2008-01-01

236

Cell labeling and magnetic separation by means of immunoreagents based on polyacrolein microspheres  

International Nuclear Information System (INIS)

Polyacrolein (PA) microspheres were synthesized by means of ionizing radiation and shown to contain aldehyde groups which form covalent bonds with amino compounds and proteins. PA microspheres made fluorescent after reaction with fluorescein-labeled antibodies were found to specifically label sensitized sheep red blood cells (SRBC). PA microspheres could also be grafted onto a variety of polymeric spheres of different sizes and composition by ionizing radiation. Gamma radiation from a cobalt source was used. These hybrid spheres, i.e., preformed polymeric spheres with PA microspheres grafted on their surfaces could bind antibodies which retained specificity of reaction with cell surface receptors. Purification of sensitized SRBC from a mixture containing chicken red blood cells (CRBC) by means of hybrid magnetic spheres in a magnetic field was demonstrated. (Auth.)

1982-08-13

237

Magnetic separation of particles from liquids in a process for reprocessing nuclear fuel  

International Nuclear Information System (INIS)

A process is described for the reprocessing of irradiated nuclear fuel material including the steps of passing the outflow from a dissolver, which outflow contains liquid and paramagnetic and ferromagnetic particles (including particles of alloys formed between uranium and certain fission products, which alloys are not soluble in nitric acid), through collecting means placed within a magnetic field and collecting the paramagnetic and ferromagnetic particles on the collecting means, the collecting means comprising generally spherical ferromagnetic bodies. (author)

1976-01-01

238

Cyclodextrin-induced lipid lateral separation in DMPC membranes: (2)H nuclear magnetic resonance study.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cholesteryl cyclodextrins, obtained by grafting a cholesterol moiety on the oligosaccharide core, combine the size selectivity of the cyclodextrin cavity with the carrier properties of model membrane systems such as micelles or liposomes. The cholesteryl cyclodextrins were incorporated as guests in chain perdeuterated dimyristoyl phosphatidylcholine (DMPC-d54) membranes. The deuterium nuclear magnetic resonance (NMR) spectra obtained with the A form of cholesteryl-beta-cyclodextrin (beta CC(A...

Roux, Michel; Auzely-velty, Rachel; Djedaini-pilard, Florence; Perly, Bruno

2002-01-01

239

Inspection of magnetic elements using forces of separation from the pole  

Energy Technology Data Exchange (ETDEWEB)

The magnetodynamic method of inspection based on the interaction between the inspected body and the source of the electromagnetic field can be used for large-scale verification of the quality of ferromagnetic components. This is carried out using the dependence of the magnetic forces acting on the component on the value of the inspected parameter (presence-absence or size of a slit, a cut-out, etc.). Examples of solving specific inspection problems and grading ferromagnetic components are given.

Zhuk, V.V.; Kalnin' , R.K.; Kuzin, S.B.; Polis, A.V.

1988-07-01

240

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

Science.gov (United States)

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

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

2014-06-25

 
 
 
 
241

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

Science.gov (United States)

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

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

2014-09-15

242

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

2007-04-01

243

Rapid Removal and Separation of Iron(II) and Manganese(II) from Micropolluted Water Using Magnetic Graphene Oxide.  

Science.gov (United States)

A novel two-dimensional carbon-based magnetic nanomaterial, magnetic graphene oxide (MGO), was prepared and then used as an efficient adsorbent. MGO showed rapid and complete removal of iron(II) (Fe) and manganese(II) (Mn) from micropolluted water bodies over a wide pH range. After saturated adsorption, MGO could be rapidly separated from water under an external magnetic field. Results of the adsorption equilibrium study indicated that the adsorption of Fe and Mn by MGO took place via monolayer heterogeneous and spontaneous processes resulting from the heterogeneity of the MGO surface as well as from the electrostatic interactions between surface acidic groups of MGO and metal ions. In addition, both the Fe and Mn uptake of MGO was very slightly affected by NaCl, although it decreased with increased humic acid in solutions. In an Fe/Mn binary aqueous system, both metal ions can be efficiently removed at low concentrations, but MGO showed preferential adsorption of Fe in a concentrated aqueous mixture. The adsorption behavior in the binary system was due to different affinities of surface oxygen-containing functional groups on MGO to Fe and Mn. Finally, unlike traditional approaches in recycling and reusing an adsorbent, the Fe- and Mn-loaded MGO can be directly applied as a new adsorbent to achieve the efficient removal of fluoride from aqueous solutions. PMID:24787443

Yan, Han; Li, Haijiang; Tao, Xue; Li, Kun; Yang, Hu; Li, Aimin; Xiao, Shoujun; Cheng, Rongshi

2014-06-25

244

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

2013-06-15

245

Wet high-intensity magnetic separation for the concentration of Witwatersrand gold-uranium ores and residues  

International Nuclear Information System (INIS)

Wet high-intensity magnetic separation (WHIMS) for the concentration of gold and uranium was tested on many Witwatersrand cyanidation residues, and on some ores and flotation tailings. The results varied, but many indicated recoveries of over 60 per cent of the gold and uranium. The main source of loss is the inefficiency of WHIMS for material of smaller particle size than 20?m. The recoveries in the continuous tests were lower than those in the batch tests. The continuous tests indicated an operational difficulty that could be experienced in practice, namely the tendency for wood chips and ferromagnetic particles to block the matrix of the separator. It was decided that a solution to the problem lies in the modification of the separator to allow continuous removal of the matrix for cleaning. A system has been developed for this purpose and is being demonstrated on a pilot-plant scale. Promising results were obtained in tests on a process that combines a coarse grind, gravity concentration, and WHIMS. In the gravity-concentration step, considerable recoveries, generally over 50 per cent, of high-grade pyrite were obtained, together with high recoveries of gold and moderate, but possibly important, recoveries of uranium. A simple model describing the operation of the WHIMS machine in terms of the operating parameters is described. This should reduce the amount of empirical testwork required for the optimization of operating conditions and should provide a basis for scale-up calculations. The economics of the WHIMS process is discussed

1979-01-01

246

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In a recent paper, we described the localization of cryptochrome 1a in the retina of domestic chickens, Gallus gallus, and European robins, Erithacus rubecula: Cryptochrome 1a was found exclusively along the membranes of the disks in the outer segments of the ultraviolet/violet single cones. Cryptochrome has been suggested to act as receptor molecule for the avian magnetic compass, which would mean that the UV/V cones have a double function: they mediate vision in the short-wavelength range a...

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

2011-01-01

247

Phase separation, thermal history and magnetic behaviour of Sr doped LaCoO3  

International Nuclear Information System (INIS)

High-resolution transmission electron microscopy observations and magnetic ac susceptibility measurements have been carried out to study the changes in the magnetic properties of La1-xSrxCoO3 samples (x?0.3) processed at different annealing temperatures, ranging from 1273 to 1573 K. Although neutron diffraction excludes the coexistence of distinct phases with different chemical composition, room temperature micrographs taken along the [0,-1,1] rhombohedral zone-axis show bright fringes of different widths, extending over regions with sizes ranging from 8 to 40 nm. These regions are detected in all the samples, whatever the Sr content or the annealing temperature Ta. However, their number depends strongly on the processing conditions and becomes smaller and smaller as Ta increases. The periodicity of the bright fringes cannot be accounted for, either by variations in the sample thickness or by crystallographic defects, but it can be simulated if the presence of aperiodically alternate Sr-rich and La-rich (0,1,1) planes is assumed. On the other hand, the susceptibility measurements show that the amount of ferromagnetic phase present in each specimen depends on its thermal history. This suggests that the segregation of a second electronic phase takes place, the nucleation of which is influenced by the spatial homogeneity of the dopant distribution. (author)

2000-11-27

248

Preparation of magnetic carbon nanotubes for separation of pyrethroids from tea samples  

International Nuclear Information System (INIS)

Magnetic carbon nanotubes (MCNTs) have been synthesized by chemical deposition of Fe3O4 nanoparticles onto carbon nanotubes. They were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction and physical property measurement system. The MCNTs were used as the sorbents for the extraction of pyrethroids including beta-cyfluthrin, cyhalothrin and cyphenothrin from tea samples. The extraction conditions, such as the amount of magnetic sorbent, shaking time and rate, washing and eluting solution have been fully investigated. The analytes desorbed from MCNTs were determined by HPLC with UV detection. Under the optimal conditions, the linearity of the method is in the range of 0.05-25 ?g g-1. The limits of detection of the three pyrethroids are 0.017, 0.010 and 0.018 ?g g-1, respectively. The relative standard deviations of within- and between-day range from 3.5 % to 6.4 %, and from 4.5 % to 29 7.3 %, respectively. In all three spiked levels (0.05, 0.5 and 5 ?g g-1), the recoveries of pyrethroids are in the range of 82.2 %-94.4 %. This method is much faster and more effective than traditional methods, and it is promising for the analysis of pesticides residues. (author)

2013-04-01

249

Phase separation, thermal history and magnetic behaviour of Sr doped LaCoO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

High-resolution transmission electron microscopy observations and magnetic ac susceptibility measurements have been carried out to study the changes in the magnetic properties of La{sub 1-x}Sr{sub x}CoO{sub 3} samples (x{<=}0.3) processed at different annealing temperatures, ranging from 1273 to 1573 K. Although neutron diffraction excludes the coexistence of distinct phases with different chemical composition, room temperature micrographs taken along the [0,-1,1] rhombohedral zone-axis show bright fringes of different widths, extending over regions with sizes ranging from 8 to 40 nm. These regions are detected in all the samples, whatever the Sr content or the annealing temperature T{sub a}. However, their number depends strongly on the processing conditions and becomes smaller and smaller as T{sub a} increases. The periodicity of the bright fringes cannot be accounted for, either by variations in the sample thickness or by crystallographic defects, but it can be simulated if the presence of aperiodically alternate Sr-rich and La-rich (0,1,1) planes is assumed. On the other hand, the susceptibility measurements show that the amount of ferromagnetic phase present in each specimen depends on its thermal history. This suggests that the segregation of a second electronic phase takes place, the nucleation of which is influenced by the spatial homogeneity of the dopant distribution. (author)

Baio, G.; Barucca, G.; Caciuffo, R.; Rinaldi, D. [Istituto Nazionale per la Fisica della Materia and Dipartimento di Scienze dei Materiali, Universita di Ancona, Ancona (Italy); Mira, J.; Rivas, J. [Departamento de Fisica Aplicada, Universidade de Santiago, Santiago de Compostela (Spain); Senaris-Rodriguez, M.A. [Departamento de Quimica Fundamental e Industrial, Universidade de A Coruna, A Coruna (Spain); Fiorani, D. [Istituto di Chimica dei Materiali, Consiglio Nazionale delle Ricerche, Monterotondo Stazione, Rome (Italy)

2000-11-27

250

Magnetic Separation for the Direct Observation of Mineral-Associated Microbial Diversity  

Science.gov (United States)

Previous studies have demonstrated that microorganisms may selectively colonize mineral surfaces in diverse environments. Mineral substrates may serve as an important source of limiting nutrients or provide electron acceptors and donors for dissimilatory reactions. This work presents a new method for characterizing the microbial diversity associated with specific components in environmental samples. Minerals are concentrated from the bulk sample according to magnetic susceptibility, resulting in compositionally distinct partitions. The microbial communities associated with these partitions are subsequently characterized using molecular techniques. Initial testing of samples from active and dormant hydrothermal chimney structures from the Lau and Fiji Basins show that mineral components may be concentrated from bulk samples without concealing pre-existing patterns of selective colonization. 16S gene surveys from environmental clone libraries reveal distinct colonization patterns for thermophilic archaea and bacteria between sulfide mineral partitions. This method offers a unique tool discerning the role of mineral composition in surface-associated diversity.

Harrison, B. K.; Orphan, V.

2006-12-01

251

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

2013-11-01

252

EVIDENCE FOR TWO SEPARATE BUT INTERLACED COMPONENTS OF THE CHROMOSPHERIC MAGNETIC FIELD  

International Nuclear Information System (INIS)

Chromospheric fibrils are generally thought to trace out low-lying, mainly horizontal magnetic fields that fan out from flux concentrations in the photosphere. A high-resolution (?0.''1 pixel–1) image, taken in the core of the Ca II 854.2 nm line and covering an unusually large area, shows the dark fibrils within an active region remnant as fine, looplike features that are aligned parallel to each other and have lengths comparable to a supergranular diameter. Comparison with simultaneous line-of-sight magnetograms confirms that the fibrils are centered above intranetwork areas (supergranular cell interiors), with one end rooted just inside the neighboring plage or strong unipolar network but the other endpoint less clearly defined. Focusing on a particular arcade-like structure lying entirely on one side of a filament channel (large-scale polarity inversion), we find that the total amount of positive-polarity flux underlying this 'fibril arcade' is ?50 times greater than the total amount of negative-polarity flux. Thus, if the fibrils represent closed loops, they must consist of very weak fields (in terms of total magnetic flux), which are interpenetrated by a more vertical field that contains most of the flux. This surprising result suggests that the fibrils in unipolar regions connect the network to the nearby intranetwork flux, while the bulk of the network flux links to remote regions of the opposite polarity, forming a second, higher canopy above the fibril canopy. The chromospheric field near the edge of the network thus has an interlaced structure resembling that in sunspot penumbrae.

2011-12-01

253

Structural analysis of the phase separation in magnetic semiconductor (Zn, Cr)Te  

Energy Technology Data Exchange (ETDEWEB)

We have studied the structural properties of the phase separation in Zn{sub 1-x}Cr{sub x}Te films grown by MBE with a relatively high Cr composition x{approx}0.2. In the combined analyses using TEM and EELS, it has been revealed that the Cr-aggregated regions are composed of precipitates of the hexagonal structure, which are formed in a particular crystallographic relation with the zinc-blende (ZB) structure of the matrix that the c-plane of the hexagonal structure nearly parallel to the (1 1 1) plane of the ZB structure. In the XRD measurements, the diffraction from the hexagonal precipitates has been detected in the {omega}-scan. From the measurements on the series of films grown at different temperatures, it has been suggested the hexagonal precipitates were formed in a larger quantity with the increase in growth temperature.

Kobayashi, Hiroaki; Nishio, Yotaro; Kanazawa, Ken [Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Kuroda, Shinji, E-mail: kuroda@ims.tsukuba.ac.jp [Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Mitome, Masanori; Bando, Yoshio [International Center For Materials Nanoarchtectonics(MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044 (Japan)

2012-08-01

254

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

Science.gov (United States)

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

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

2013-01-01

255

The performance of an industrial wet high-intensity magnetic separator for the recovery of gold and uranium  

International Nuclear Information System (INIS)

After bench-scale and pilot-plant tests in which it was shown that wet high-intensity magnetic separation (WHIMS) can achieve good recoveries of gold and uranium from Witwatersrand residues, a production-size machine was installed at a gold mine. The mechanical and metallurgical performance of this machine have been satisfactory, and the economics of the process are attractive. WHIMS can be combined with other unit operations like flotation for the optimization of overall gold and uranium recoveries. This concept is shown to be relevant, not only to operations for the retreatment of tailings, but to processes for the treatment of coarser material. In the latter, there is a saving in energy consumption compared with the energy required for the fine grinding of the total feed, and a material suitable for underground backfill can be produced. Improved, more cost-effective WHIMS machines currently under development are also described

1984-01-01

256

Pressure induced magnetic phase separation in La0.75Ca0.25MnO3 manganite  

Science.gov (United States)

The pressure dependence of the Curie temperature TC(P) in La0.75Ca0.25MnO3 was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature TIM(P) (Postorino et al 2003 Phys. Rev. Lett. 91 175501). The behavior of the two temperatures appears similar over the whole pressure range, suggesting a key role of magnetic double-exchange also in the pressure regime where the superexchange interaction is dominant. The coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data.

Baldini, M.; Capogna, L.; Capone, M.; Arcangeletti, E.; Petrillo, C.; Goncharenko, I.; Postorino, P.

2012-02-01

257

Pressure induced magnetic phase separation in La0.75Ca0.25MnO3 manganite  

International Nuclear Information System (INIS)

The pressure dependence of the Curie temperature TC(P) in La0.75Ca0.25MnO3 was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature TIM(P) (Postorino et al 2003 Phys. Rev. Lett. 91 175501). The behavior of the two temperatures appears similar over the whole pressure range, suggesting a key role of magnetic double-exchange also in the pressure regime where the superexchange interaction is dominant. The coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data. (paper)

2012-02-01

258

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

Science.gov (United States)

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 cryopreservation, however the fertilization potential of these cells has yet to be determined. PMID:23237064

Faezah, S S M; Zuraina, F M Y; Farah, J H F; Khairul, O; Hilwani, N I; Iswadi, M I; Fang, C N; Zawawi, I; Abas, O M; Fatimah, S I

2014-08-01

259

Preparation of guanidine group functionalized magnetic nanoparticles and the application in preconcentration and separation of acidic protein.  

Science.gov (United States)

Guanidine group (Gnd) functionalized magnetic nanoparticles (Fe3O4@SiO2@NH2-Gnd) were synthesized and characterized in this work for the first time. The characterization of Fe3O4@SiO2@ NH2-Gnd nanoparticles was demonstrated by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, vibration sample magnetometer, and zeta potential analyzer. The novel multifunctional nanoparticles were served as a solid-phase extraction sorbent for easy isolation and preconcentration of acidic protein from aqueous solution only using a magnet. Bovine serum albumin (BSA) was selected as a model protein and the main experimental parameters influencing the adsorption and desorption efficiency were investigated and optimized. Under the optimum conditions, the particles reached saturated adsorption within 20 min and exhibited significant specific recognition for the acidic proteins. Fifteen fold enrichment efficiency was achieved and the detection limits was 45 ng x mL(-1) for BSA by capillary electrophoresis (CE). The practical application of the novel nanoparticles as a sorbent for the isolation and preconcentration of acidic proteins from basic proteins was demonstrated by effective separation and enrichment of bovine serum albumin from lysozyme and cytochrome C mixture, which was assayed by CE. PMID:22408914

Dong, Ya-Lei; Zhang, Hai-Juan; Yan, Na; Zhou, Lei; Zhang, Zhen-Yang; Rahman, Zia Ur; Chen, Xing-Guo

2011-12-01

260

Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation  

Science.gov (United States)

Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions (i.e., reduction temperature, 1250°C; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%). The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.

Sun, Yong-sheng; Han, Yue-xin; Gao, Peng; Wang, Ze-hong; Ren, Duo-zhen

2013-05-01

 
 
 
 
261

Separating spatial and temporal variations in auroral electric and magnetic fields by Cluster multipoint measurements  

Directory of Open Access Journals (Sweden)

Full Text Available Cluster multipoint measurements of the electric and magnetic fields from a crossing of auroral field lines at an altitude of 4RE are used to show that it is possible to resolve the ambiguity of temporal versus spatial variations in the fields. We show that the largest electric fields (of the order of 300mV/m when mapped down to the ionosphere are of a quasi-static nature, unipolar, associated with upward electron beams, stable on a time scale of at least half a minute, and located in two regions of downward current. We conclude that they are the high-altitude analogues of the intense return current/black auroral electric field structures observed at lower altitudes by Freja and FAST. In between these structures there are temporal fluctuations, which are shown to likely be downward travelling Alfvén waves. The periods of these waves are 20-40s, which is not consistent with periods associated with either the Alfvénic ionospheric resonator, typical field line resonances or substorm onset related Pi2 oscillations. The multipoint measurements enable us to estimate a lower limit to the perpendicular wavelength of the Alfvén waves to be of the order of 120km, which suggests that the perpendicular wavelength is similar to the dimension of the region between the two quasi-static structures. This might indicate that the Alfvén waves are ducted within a wave guide, where the quasi-static structures are associated with the gradients making up this waveguide.

T. Karlsson

2004-07-01

262

Separation of the magnetic phases at the N\\'{e}el point in the diluted spin-Peierls magnet CuGeO3  

CERN Multimedia

The impurity induced antiferromagnetic ordering of the doped spin-Peierls magnet Cu(1-x)Mg(x)GeO(3) was studied by ESR technique. Crystals with the Mg concentration x<4% demonstrate a coexistence of paramagnetic and antiferromagnetic ESR modes. This coexistence indicates the separation of a macroscopically uniform sample in the paramagnetic and antiferromagnetic phases. In the presence of the long-range spin-Peierls order (in a sample with x=1.71%) the volume of the antiferromagnetic phase immediately below the N\\'{e}el point T_N is much smaller than the volume of the paramagnetic phase. In the presence of the short-range spin-Peierls order (in samples with x=2.88%, x= 3.2%) there are comparable volumes of paramagnetic and antiferromagnetic phases at T=T_N. The fraction of the antiferromagnetic phase increases with lowering temperature. In the absence of the spin-Peierls dimerization (at x=4.57%)the whole sample exhibits the transition into the antiferromagnetic state and there is no phase separation. The ...

Glazkov, V N; Uchinokura, K; Masuda, T

2001-01-01

263

Magnetic state of the structural separated anion-deficient La0.70Sr0.30MnO2.85 manganite  

Science.gov (United States)

The results of neutron diffraction studies of the La0.70Sr0.30MnO2.85 compound and its behavior in an external magnetic field are stated. It is established that in the 4-300 K temperature range, two structural perovskite phases coexist in the sample, which differ in symmetry (groups Rbar 3c and I4/ mcm). The reason for the phase separation is the clustering of oxygen vacancies. The temperature (4-300 K) and field (0-140 kOe) dependences of the specific magnetic moment are measured. It is found that in zero external field, the magnetic state of La0.70Sr0.30MnO2.85 is a cluster spin glass, which is the result of frustration of Mn3+-O-Mn3+ exchange interactions. An increase in external magnetic field up to 10 kOe leads to fragmentation of ferromagnetic clusters and then to an increase in the degree of polarization of local spins of manganese and the emergence of long-range ferromagnetic order. With increasing magnetic field up to 140 kOe, the magnetic ordering temperature reaches 160 K. The causes of the structural and magnetic phase separation of this composition and formation mechanism of its spin-glass magnetic state are analyzed.

Trukhanov, S. V.; Trukhanov, A. V.; Vasiliev, A. N.; Balagurov, A. M.; Szymczak, H.

2011-11-01

264

Correlation between magnetic and transport properties of phase separated La$_{0.5}$Ca$_{0.5}$MnO$_{3}$  

CERN Document Server

The effect of low magnetic fields on the magnetic and electrical transport properties of polycrystalline samples of the phase separated compound La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ is studied. The results are interpreted in the framework of the field induced ferromagnetic fraction enlargement mechanism. A fraction expansion coefficient af, which relates the ferromagnetic fraction f with the applied field H, was obtained. A phenomenological model to understand the enlargement mechanism is worked out.

Sacanell, J; Ghivelder, L; Polla, G; Parisi, F

2001-01-01

265

The XYZ-difference method with polarized neutrons and the separation of coherent, spin incoherent, and magnetic scattering cross sections in a multidetector  

International Nuclear Information System (INIS)

Equations are derived for the polarization analysis in a multidetector to separate coherent, spin incoherent, and magnetic scattering using three-dimensional analysis or the xyz-difference method. Then the conditions for the magnetic guide fields to rotate the polarization into the three directions x, y, and z are discussed on the basis of the existing instrument D7 at the ILL in Grenoble. (orig.)

1993-02-01

266

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

Science.gov (United States)

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

Sheha, Reda R

2012-12-15

267

Silence of magnetic layers to magnetoresistive process and electronic separation at low temperatures in $(La,Sm)Mn_{2}Ge_{2}$  

CERN Multimedia

A closer look at the temperature (T) dependence of magnetoresistance (MR) oftwo polycrystalline magnetic compounds, LaMn$_2$Ge$_2$ and SmMn$_2$Ge$_2$,previously reported by us, is made. A common feature for both these compoundsis that the low temperature MR is positive (say, below, 30 K) in spite of thefact that both are ferromagnetic at such low temperatures; in addition, MR as afunction of magnetic field (H) does not track magnetization (M) in the sensethat M saturates at low fields, while MR varies linearly with H. Theseobservations suggest that the magnetic layers interestingly do not dominate lowtemperature magnetotransport process. Interestingly enough, as the T isincreased, say around 100 K, these magnetic layers dominate MR process asevidenced by the tracking of M and MR in SmMn$_2$Ge$_2$. These results temptsus to propose that there is an unusual "electronic separation" for MR processas the T is lowered in this class of compounds.

Sampathkumaran, E V; Paulose, P L; Majumdar, S N; Majumdar, Subham

2000-01-01

268

Transcranial magnetic stimulation in a finger-tapping task separates motor from timing mechanisms and induces frequency doubling.  

Science.gov (United States)

We study the interplay between motor programs and their timing in the brain by using precise pulses of transcranial magnetic stimulation (TMS) applied to the primary motor cortex. The movement of the finger performing a tapping task is periodically perturbed in synchronization with a metronome. TMS perturbation can profoundly affect both the finger trajectory and its kinematics, but the tapping accuracy itself is surprisingly not affected. The motion of the finger during the TMS perturbation can be categorized into two abnormal behaviors that subjects were unaware of: a doubling of the frequency of the tap and a stalling of the finger for half the period. More stalls occurred as the tapping frequency increased. In addition, an enhancement of the velocity of the finger on its way up was observed. We conclude that the timing process involved in controlling the tapping movement is separate from the motor processes in charge of execution of the motor commands. We speculate that the TMS is causing a release of the motor plan ahead of time into activation mode. The observed doubles and stalls are then the result of an indirect interaction in the brain, making use of an existing motor plan to correct the preactivation and obtain the temporal goal of keeping the beat. PMID:17488200

Levit-Binnun, Nava; Handzy, Nestor Z; Peled, Avi; Modai, Ilan; Moses, Elisha

2007-05-01

269

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

270

Human functional magnetic resonance imaging reveals separation and integration of shape and motion cues in biological motion processing.  

Science.gov (United States)

In a series of human functional magnetic resonance imaging experiments, we systematically manipulated point-light stimuli to identify the contributions of the various areas implicated in biological motion processing (for review, see Giese and Poggio, 2003). The first experiment consisted of a 2 x 2 factorial design with global shape and kinematics as factors. In two additional experiments, we investigated the contributions of local opponent motion, the complexity of the portrayed movement and a one-back task to the activation pattern. Experiment 1 revealed a clear separation between shape and motion processing, resulting in two branches of activation. A ventral region, extending from the lateral occipital sulcus to the posterior inferior temporal gyrus, showed a main effect of shape and its extension into the fusiform gyrus also an interaction. The dorsal region, including the posterior inferior temporal sulcus and the posterior superior temporal sulcus (pSTS), showed a main effect of kinematics together with an interaction. Region of interest analysis identified these interaction sites as the extrastriate and fusiform body areas (EBA and FBA). The local opponent motion cue yielded only little activation, limited to the ventral region (experiment 3). Our results suggest that the EBA and the FBA correspond to the initial stages in visual action analysis, in which the performed action is linked to the body of the actor. Moreover, experiment 2 indicates that the body areas are activated automatically even in the absence of a task, whereas other cortical areas like pSTS or frontal regions depend on the complexity of movements or task instructions for their activation. PMID:19494153

Jastorff, Jan; Orban, Guy A

2009-06-01

271

Analysis by means of gas chromatography, mass spectrometry and nuclear magnetic resonance (with hydrogen 1/carbon 13 spectrum) of saturated compounds separated from products of coal hydrogenation  

Energy Technology Data Exchange (ETDEWEB)

Gas chromatography, mass spectrometry (the Hewlett-Packard 5880 A chromatograph) and nuclear magnetic resonance in hydrogen 1/carbon 13 spectrum (JEOL FX 90 Q spectrometer) were used for quantitative and qualitative chemical analysis and for determining molecular structure of the fractions of paraffin-naphthalene hydrocarbons separated from the products of direct non-catalytic hydrogenation of Polish flame coal. Properties of saturated compounds separated from the hydrogenation products as well as the products of their further catalytic hydrogenation were analyzed. Analysis results are shown in 4 diagrams and 4 tables. 35 refs.

Pazdziorek, T.; Rusin, A.

1986-05-01

272

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

International Nuclear Information System (INIS)

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

2009-09-01

273

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

274

Cluster glass magnetism in the phase-separated Nd2/3Ca1/3MnO3 perovskite  

International Nuclear Information System (INIS)

A detailed study of the low-temperature magnetic state and the relaxation in the phase-separated colossal magnetoresistance Nd2/3Ca1/3MnO3 perovskite has been carried out. Clear experimental evidence of the cluster-glass magnetic behavior of this compound has been revealed. Well defined maxima in the in-phase linear ac susceptibility ??(T) were observed, indicative of the magnetic glass transition at Tg?60 K. Strongly divergent zero-field-cooled and field-cooled static magnetizations and frequency dependent ac susceptibility are evident of the glassy-like magnetic state of the compound at low temperatures. The frequency dependence of the cusp temperature Tmax of the ??(T) susceptibility was found to follow the critical slowing down mechanism. The Cole–Cole analysis of the dynamic susceptibility at low temperature has shown extremely broad distribution of relaxation times, indicating that spins are frozen at “macroscopic” time scale. Slow relaxation in the zero-field-cooled magnetization has been experimentally revealed. The obtained results do not agree with a canonical spin-glass state and indicate a cluster glass magnetic state of the compound below Tg, associated with its antiferromagnetic–ferromagnetic nano-phase segregated state. It was found that the relaxation mechanisms below the cluster glass freezing temperature Tg and above it are strongly different. Magnetic field up to about ?0H?0.4 T suppresses the glassy magnetic state of the compound. - Highlights: ? Cluster-glass magnetic state of Nd2/3Ca1/3MnO3 below Tg?60 K has been revealed. ? Magnetic fields up to about ?0H?0.4 T suppress the glassy magnetic state. ? Extremely broad distribution of relaxation times has been found below Tg. ? The relaxation mechanisms below and above Tg are found to be strongly different. ? Cluster-glass magnetic behavior of Nd2/3Ca1/3MnO3 is associated with its phase segregated state.

2012-09-01

275

Improved accuracy of U-Pb zircon dating by selection of more concordant fractions using a high gradient magnetic separation technique  

International Nuclear Information System (INIS)

A loop of soft iron wire or a paper clip or a ferromagnetic grid mounted between the poles of an electromagnet picks up and allows further magnetic separation of zircons previously found to be non-magnetic on a Frantz Isodynamic Separator. Tests on previously analysed samples indicate that most such zircons that are fairly discordant (say approximately 10%) can be picked up and isolated from associated grains that are more concordant. Tests on new samples indicate that even when most grains can be picked up the last few percent of the sample contain less uranium, and are more concordant than the bulk sample. The degree of discordance is the dominant factor affecting the uncertainty of U-Pb zircon ages both because of the error amplification in projections, and because the assumption of a simple two-stage system may not be valid. Only by eliminating or reducing discordance can errors approaching the uncertainty in a single analysis, say +- 2 m.y. for 2700 m.y. rocks, be achieved. Rutile normally concentrated with zircon as non-magnetic has been successfully removed from a small amount of low uranium zircon, using the high intensity separation technique. (author)

1982-01-01

276

Improved accuracy of U-Pb zircon dating by selection of more concordant fractions using a high gradient magnetic separation technique  

Science.gov (United States)

A loop of soft iron wire or a paper clip or a ferromagnetic grid mounted between the poles of an electromagnet picks up and allows further magnetic separation of zircons previously found to be non-magnetic on a Frantz Isodynamic Separator. Tests on previously analysed samples indicate that most such zircons that are fairly discordant (say ~10%) can be picked up and isolated from associated grains that are more concordant. Tests on new samples indicate that even when most grains can be picked up the last few percent of the sample contain less uranium, and are more concordant than the bulk sample. The degree of discordance is the dominant factor affecting the uncertainty of U-Pb zircon ages both because of the error amplification in projections, and because the assumption of a simple two-stage system may not be valid. Only by eliminating or reducing discordance can errors approaching the uncertainty in a single analysis, say ±2 m.y. for 2700 m.y. rocks, be achieved. Rutile normally concentrated with zircon as non-magnetic has been successfully removed from a small amount of low uranium zircon, using the high intensity separation technique.

Krogh, T. E.

1982-04-01

277

Improved accuracy of U-Pb zircon dating by selection of more concordant fractions using a high gradient magnetic separation technique  

International Nuclear Information System (INIS)

A loop of soft iron wire or a paper clip or a ferromagnetic grid mounted between the poles of an electromagnet picks up and allows further magnetic separation of zircons previously found to be non-magnetic on a Frantz Isodynamic Separator. Tests on previously analysed samples indicate that most such zircons that are fairly discordant (say approximately 10%) can be picked up and isolated from associated grains that are more concordant. Tests on new samples indicate that even when most grains can be picked up the last few percent of the sample contain less uranium, and are more concordant than the bulk sample. The degree of discordance is the dominant factor affecting the uncertainty of U-Pb zircon ages both because of the error amplification in projections, and because the assumption of a simple two-stage system may not be valid. Only by eliminating or reducing discordance can errors approaching the uncertainty in a single analysis, say +-2m.y. for 2700m.y. rocks, be achieved. Rutile normally concentrated with zircon as non-magnetic has been successfully removed from a small amount of low uranium zircon, using the high intensity separation technique. (author)

1982-01-01

278

An integrated passive micromixer-magnetic separation-capillary electrophoresis microdevice for rapid and multiplex pathogen detection at the single-cell level.  

Science.gov (United States)

Here we report an integrated microdevice consisting of an efficient passive mixer, a magnetic separation chamber, and a capillary electrophoretic microchannel in which DNA barcode assay, target pathogen separation, and barcode DNA capillary electrophoretic analysis were performed sequentially within 30 min for multiplex pathogen detection at the single-cell level. The intestine-shaped serpentine 3D micromixer provides a high mixing rate to generate magnetic particle-pathogenic bacteria-DNA barcode labelled AuNP complexes quantitatively. After magnetic separation and purification of those complexes, the barcode DNA strands were released and analyzed by the microfluidic capillary electrophoresis within 5 min. The size of the barcode DNA strand was controlled depending on the target bacteria (Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella typhimurium), and the different elution time of the barcode DNA peak in the electropherogram allows us to recognize the target pathogen with ease in the monoplex as well as in the multiplex analysis. In addition, the quantity of the DNA barcode strand (?10(4)) per AuNP is enough to be observed in the laser-induced confocal fluorescence detector, thereby making single-cell analysis possible. This novel integrated microdevice enables us to perform rapid, sensitive, and multiplex pathogen detection with sample-in-answer-out capability to be applied for biosafety testing, environmental screening, and clinical trials. PMID:21870015

Jung, Jae Hwan; Kim, Gha-Young; Seo, Tae Seok

2011-10-21

279

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 th...

Saurel, Damien; Brulet, Annie; Heinemann, Andre; Martin, Christine; Mercone, Silvana; Simon, Charles

2006-01-01

280

Synthesis of a Thin-Layer MnO2 Nanosheet-Coated Fe3O4 Nanocomposite as a Magnetically Separable Photocatalyst.  

Science.gov (United States)

A facile hydrothermal method combined with a mild ultrasonic means has been developed for the fabrication of a magnetically recyclable thin-layer MnO2 nanosheet-coated Fe3O4 nanocomposite. The photocatalytic studies suggest that the MnO2/Fe3O4 nanocomposite shows excellent photocatalytic efficiency and stability simultaneously for the degradation of methylene blue under UV-vis light irradiation. Moreover, its good acid resistance and stable recyclability are very important for its future practical application as a photocatalyst. Magnetic measurements verify that the MnO2/Fe3O4 nanocomposite possesses a ferromagnetic nature, which can be effectively separated for reuse by simply applying an external magnetic field after the photocatalytic reaction. This novel composite material may have potential applications in water treatment, degradation of dye pollutants, and environmental cleaning. PMID:24856355

Zhang, Lishu; Lian, Jianshe; Wu, Longyun; Duan, Zhenrong; Jiang, Jun; Zhao, Lijun

2014-06-17

 
 
 
 
281

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)

2007-12-27

282

Annealing control of magnetic anisotropy and phase separation in CoFe2O4-BaTiO3 nanocomposite films  

Science.gov (United States)

Multiferroic heteroepitaxial nanocomposite films of BaTiO3 and CoFe2O4 (CFO) have been grown by pulsed laser deposition employing alternating ablation of two ceramic targets. Films grown at temperatures between 650 °C and 710 °C contain columnar CFO grains about 10-20 nm in diameter embedded in a BaTiO3 matrix. The very strong vertical compression of these grains causes large perpendicular magnetic anisotropy. Post-growth annealing treatments above the growth temperature gradually release the compression. This allows one to tune the stress-induced magnetic anisotropy. Additionally, annealing leads to substantial enhancement of the saturation magnetization MS. Since MS of a pure CFO film remains unchanged by a similar annealing procedure, MS is proposed to depend on the volume fraction of the obtained CFO phase. We suggest that MS can be utilized to monitor the degree of phase separation in nanocomposite films.

Rafique, Mohsin; Herklotz, A.; Guo, E.-J.; Roth, R.; Schultz, L.; Dörr, K.; Manzoor, Sadia

2013-12-01

283

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

284

Observation of dynamical spin-dependent electron interactions and screening in magnetic transitions via core-level multiplet-energy separations  

International Nuclear Information System (INIS)

Highlights: ? Gd 5s and 4s multiplet splittings of Gd(0001) change during magnetic transitions. ?·Atomic multiplet theory and LDA+U calculations partially explain these results. ?·Provide a novel probe of dynamical spin-dependent screening/magnetic fluctuations. ? Suggest future experiments in a time-resolved mode, e.g. using free electron lasers. -- Abstract: The magnetic phase transitions for Gd(0 0 0 1) grown on W(1 1 0) – a bulk transition at 293 K and a surface transition about 85 K above this – are found to influence the energy separation of the Gd 5s and 4s core-photoelectron doublets. The 5s doublet separation ?E5s changes over a range of temperatures spanning these transitions, and decreases by a maximum of 60 meV in this region, but then recovers its original value; the 4s doublet shows a smaller change in the reverse direction, which does not recover at high temperature. Some of these effects are semi-quantitatively understood from free-atom multiplet theory and from theoretical calculations based on all-electron LDA+U calculations including 4f electron correlation effects. However, the high-temperature behavior of the data also suggest a dynamical nature to these effects via spin-dependent electron screening that is influenced by magnetic fluctuations. Several avenues for studying such effects in a time-resolved manner in future experiments are discussed

2013-08-01

285

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

286

Observation of dynamical spin-dependent electron interactions and screening in magnetic transitions via core-level multiplet-energy separations  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? Gd 5s and 4s multiplet splittings of Gd(0001) change during magnetic transitions. ?·Atomic multiplet theory and LDA+U calculations partially explain these results. ?·Provide a novel probe of dynamical spin-dependent screening/magnetic fluctuations. ? Suggest future experiments in a time-resolved mode, e.g. using free electron lasers. -- Abstract: The magnetic phase transitions for Gd(0 0 0 1) grown on W(1 1 0) – a bulk transition at 293 K and a surface transition about 85 K above this – are found to influence the energy separation of the Gd 5s and 4s core-photoelectron doublets. The 5s doublet separation ?E{sub 5s} changes over a range of temperatures spanning these transitions, and decreases by a maximum of 60 meV in this region, but then recovers its original value; the 4s doublet shows a smaller change in the reverse direction, which does not recover at high temperature. Some of these effects are semi-quantitatively understood from free-atom multiplet theory and from theoretical calculations based on all-electron LDA+U calculations including 4f electron correlation effects. However, the high-temperature behavior of the data also suggest a dynamical nature to these effects via spin-dependent electron screening that is influenced by magnetic fluctuations. Several avenues for studying such effects in a time-resolved manner in future experiments are discussed.

Tober, Eric D.; Palomares, F. Javier; Ynzunza, Ramon X.; Denecke, Reinhard [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Morais, Jonder [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Liesegang, John [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Department of Physics, La Trobe University, Melbourne, VIC 3086 (Australia); Hussain, Zahid [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Shick, Alexander B.; Pickett, Warren E. [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Fadley, Charles S., E-mail: fadley@lbl.gov [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2013-08-15

287

Field-controlled phase separation at the impurity-induced magnetic ordering in the spin-Peierls magnet CuGeO3  

CERN Multimedia

The fraction of the paramagnetic phase surviving at the impurity-induced antiferromagnetic order transition of the doped spin-Peierls magnet Cu(1-x)Mg(x)GeO3 (x < 5%) is found to increase with an external magnetic field. This effect is qualitatively explained by the competition of Zeeman energy and exchange interaction between local antiferromagnetic clusters

Glazkov, V N; Krug von Nidda, H A; Loidl, A; Uchinokura, K; Masuda, T

2004-01-01

288

Effect of an external magnetic field on a critical point for phase separation in a dusty plasma  

International Nuclear Information System (INIS)

The effect of an external magnetic field on a critical point for phase transitions in a dusty plasma is investigated. It is shown that the ambient magnetic field increases the effective hard core radius of dust particles, which, in turn, would affect a critical point in terms of the Coulomb coupling parameter and the ratio between the inter-dust grain spacing and the dusty plasma Debye radius. The present result may be useful in understanding the phenomenon of liquid-vapor phase transitions in laboratory dusty plasmas that are held in an external magnetic field.

2012-09-01

289

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

290

Magnetic study of CaMn0.96Mo0.04O3, canting vs. phase separation  

International Nuclear Information System (INIS)

CaMn0.96Mo0.04O3 is an example of Mn4+ rich perovskite manganites, which exhibits a net ferromagnetic component at low temperature, observed by dc magnetization and ac susceptibility. To characterize the magnetic state of this compound, neutron powder diffraction was carried out in the 2-400 K temperature range, showing that it is necessary to use three components (ferromagnetic and G- and A-type antiferromagnetic) to describe it. This particular state is in agreement with the unusual magnetic behaviour observed by macroscopic measurements and is compared to the one observed for manganites with similar Mn valence but obtained by A-site substitution.

2009-12-01

291

Effect of transverse magnetic field on the point of separation in some retarded boundary layer flows of the Goertler type  

International Nuclear Information System (INIS)

A solution has been obtained for the laminar MHD boundary layer of an incompressible fluid of constant conductivity along a semi-infinite flat plate in some retarded flows of the Goertler type in the presence of transverse magnetic field with or without suction and injection. The momentum integral equation and two wall compatibility conditions have been used to find an approximate solution with th help of a fifth degree velocity profile. It has been found that shift in the point of separatio significantly increases with the increase in the intensity of the magnetic field. (author). 6 refs

1988-01-01

292

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 susceptibi...

Lakshmi, L. Seetha; Sridharan, V.; Natarajan, D. V.; Chandra, Sharat; Sastry, V. Sankara; Radhakrishnan, T. S.; Pandian, Ponn; Narayanasamy, A.

2002-01-01

293

Magnetic relaxation in La0.250Pr0.375Ca0.375MnO3 with varying phase separation  

CERN Multimedia

We have studied the magnetic relaxation properties of the phase-separated manganite compound La0.250Pr0.375Ca0.375MnO3 . A series of polycrystalline samples was prepared with different sintering temperatures, resulting in a continuous variation of phase fraction between metallic (ferromagnetic) and charge-ordered phases at low temperatures. Measurements of the magnetic viscosity show a temperature and field dependence which can be correlated to the static properties. Common to all the samples, there appears to be two types of relaxation processes - at low fields associated with the reorientation of ferromagnetic domains and at higher fields associated with the transformation between ferromagnetic and non-ferromagnetic phases.

Deac, I G; Kim, B G; Cheong, S W; Schiffer, P

2002-01-01

294

A self-consistent two-dimensional resistive fluid theory of field-aligned potential structures including charge separation and magnetic and velocity shear  

Science.gov (United States)

A self-consistent two-fluid theory that includes the magnetic field and shear patterns is developed to model stationary electrostatic structures with field-aligned potential drops. Shear flow is also included in the theory since this seems to be a prominent feature of the structures of interest. In addition, Ohmic dissipation, a Hall term, and pressure gradients in a generalized Ohm's law, modified for cases without quasi-neutrality, are included. In the analytic theory, the electrostatic force is balanced by field-aligned pressure gradients (i.e., thermal effects in the direction of the magnetic field) and by pressure gradients and magnetic stresses in the perpendicular direction. Within this theory, simple examples of applications are presented to demonstrate the kind of solutions resulting from the model. The results show how the effects of charge separation and shear in the magnetic field and the velocity can be combined to form self-consistent structures such as are found to exist above the aurora, suggested also in association with solar flares.

Hesse, Michael; Birn, Joachim; Schindler, Karl

1990-01-01

295

Fabrication of magnetically separable fluorescent terbium-based MOF nanospheres for highly selective trace-level detection of TNT.  

Science.gov (United States)

In this work, we present novel kinds of Fe3O4@Tb-BTC magnetic metal-organic framework (MOF) nanospheres which possess both magnetic characteristics and fluorescent properties using a layer by layer assembly technique. The structure and morphology of the as-prepared Fe3O4@Tb-BTC were systematically characterized and it was applied in detection of nitroaromatic explosives, such as 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 2-nitrotoluene (2-NT), 4-nitrotoluene (4-NT), nitrobenzene (NB) and picric acid (PA). The results indicate that the fluorescence intensity of Fe3O4@Tb-BTC can be quenched by all analytes studied in the present work. Remarkably, the as-synthesized nanospheres exhibit high sensitivity for 2,4,6-trinitrotoluene (TNT) detection with Ksv value of (94?800 M(-1)). Besides, the magnetic nanospheres can be easily recycled, which makes it more convenient for reutilization and friendly to the environment. The results show that it has broad application prospects in the detection of nitroaromatic explosives. PMID:24452313

Qian, Jing-Jing; Qiu, Ling-Guang; Wang, Yi-Min; Yuan, Yu-Peng; Xie, An-Jian; Shen, Yu-Hua

2014-03-14

296

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

297

Supported hydrophobic ionic liquid on magnetic nanoparticles as a new sorbent for separation and preconcentration of lead and cadmium in milk and water samples  

International Nuclear Information System (INIS)

We have prepared a highly selective and efficient sorbent for the simultaneous separation and preconcentration of lead and cadmium ions from milk and water samples. An ionic liquid was deposited on the surface of magnetic nanoparticles (IL-MNPs) and used for solid phase extraction of these ions. The IL-MNPs carrying the target metals were then separated from the sample solution by applying an external magnetic field. Lead and cadmium were almost quantitatively retained by the IL-MNPs, and then eluted with nitric acid. The effect of different variables on solid phase extraction was investigated. The calibration curve is linear in the range from 0.3 to 20 ng mL-1 of Cd(II), and from 5 to 330 ng mL-1 of Pb(II) in the initial solution. Under optimum conditions, the detection limits are 1.61 and 0.122 ?g L-1 for Pb(II) and Cd(II) respectively. Relative standard deviations (n=10) were 2.87 % and 1.45 % for 0.05 ?g mL-1 and 0.2 ?g mL-1 of Cd (II) and Pb (II) respectively. The preconcentration factor is 200 for both of ions. (author)

2012-11-01

298

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

International Nuclear Information System (INIS)

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

2001-10-01

299

Efficient separation and sensitive detection of Listeria monocytogenes using an impedance immunosensor based on magnetic nanoparticles, a microfluidic chip, and an interdigitated microelectrode.  

Science.gov (United States)

Listeria monocytogenes continues to be a major foodborne pathogen that causes food poisoning, and sometimes death, among immunosuppressed people and abortion among pregnant women. In this study, magnetic nanoparticles with a diameter of 30 nm were functionalized with anti-L. monocytogenes antibodies via biotin-streptavidin bonds to become immunomagnetic nanoparticles (IMNPs) to capture L. monocytogenes in a sample during a 2-h immunoreaction. A magnetic separator was used to collect and hold the IMNPs-L. monocytogenes complex while the supernatants were removed. After the washing step, the nanoparticle-L. monocytogenes complex was separated from the sample and injected into a microfluidic chip. The impedance change caused by L. monocytogenes was measured by an impedance analyzer through the interdigitated microelectrode in the microfluidic chip. For L. monocytogenes in phosphate-buffered saline solution, up to 75% of the cells in the sample could be separated, and as few as three to five cells in the microfluidic chip could be detected, which is equivalent to 10(3) CFU/ml of cells in the original sample. The detection of L. monocytogenes was not interfered with by other major foodborne bacteria, including E. coli O157:H7, E. coli K-12, L. innocua, Salmonella Typhimurium, and Staphylococcus aureus. A linear correlation (R(2) = 0.86) was found between the impedance change and the number of L. monocytogenes in a range of 10(3) to 10(7) CFU/ml. Equivalent circuit analysis indicated that the impedance change was mainly due to the decrease in medium resistance when the IMNPs-L. monocytogenes complexes existed in mannitol solution. Finally, the immunosensor was evaluated with food sample tests; the results showed that, without preenrichment and labeling, 10(4) and 10(5) CFU/ml L. monocytogenes in lettuce, milk, and ground beef samples could be detected in 3 h. PMID:23127703

Kanayeva, Damira A; Wang, Ronghui; Rhoads, Douglas; Erf, Gisela F; Slavik, Michael F; Tung, Steve; Li, Yanbin

2012-11-01

300

Pressure induced magnetic phase separation in La0.75Ca0.25MnO3 manganite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pressure dependence of the Curie temperature T-C(P) in La0.75Ca0.25MnO3 was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature T-IM(P) (Postorino et al 2003 Phys. Rev. Lett. 91 175501). The behavior of the two temperatures appears similar over the whole pressure range, suggesting a key role of magnetic double-exchange also in the pressure regime where the superexchange interaction is dominant. The coexistence of antiferromagnetic and ferromagnet...

Baldini, M.; Capogna, L.; Capone, M.; Arcangeletti, E.; Petrillo, C.; Goncharenko, I.; Postorino, P.

2012-01-01

 
 
 
 
301

Electromagnetic Mass Separator for Heavy Element Radioisotope Separation.  

Science.gov (United States)

An electromagnetic mass separator of a sector type intended for uranium isotope separation and U-234 production is described. The working chamber, magnet and vacuum system are located in a special ''canyon''. Operation controlling of the vacuum system, po...

M. K. Abdulakhatov G. A. Akopov V. S. Belykh T. D. Gogoleva A. G. Evdokimov

1980-01-01

302

Selective separation of mercury(II) using magnetic chitosan resin modified with Schiff's base derived from thiourea and glutaraldehyde  

International Nuclear Information System (INIS)

Magnetic chitosan resin was chemically modified by a Schiff's base cross-linker. The interaction of the resin obtained with Hg(II) was studied and uptake value of 2.8 mmol/g was reported. The kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and follow the pseudo-second-order kinetics. The selectivity of Hg(II) from other different metal ions in solutions using the studied resin was also reported. Breakthrough curves for the recovery of Hg(II) were studied. The critical bed height was found to be 2.05 cm. The adsorbed Hg(II) was eluted from the resin effectively using 0.1 M potassium iodide

2008-03-01

303

Drive tube 60009 - A chemical study of magnetic separates of size fractions from five strata. [lunar soil analysis  

Science.gov (United States)

Each bulk soil and both the magnetic and nonmagnetic components of the 90-150 micron and below 20 micron fractions of five soils from drive tube 60009 were analyzed. Samples were analyzed for FeO, Na2O, Sc, Cr, Co, Ni, Hf, Ta, Th, La, Ce, Sm, Eu, Tb, Yb, and Lu by neutron activation analysis. Several samples were fused and analyzed for major elements by electron microprobe analysis. Compositional variations are not systematically related to depth. The compositions of the five soils studied are well explained by a two-component mixing model whose end members are a submature Apollo 16-type soil and an extremely immature anorthositic material similar to 60025. There is evidence that the anorthositic component had received a small amount of exposure before these soils were mixed. After mixing, the soils received little exposure suggesting mixing and deposition on a rapid time scale.

Blanchard, D. P.; Jacobs, J. W.; Brannon, J. C.; Brown, R. W.

1976-01-01

304

Potential environmental benefits of improving recycling of polyolefines â?? 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

305

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

CERN Document Server

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

306

Immunochromatographic strip for rapid detection of Cronobacter in powdered infant formula in combination with silica-coated magnetic nanoparticles separation and 16S rRNA probe.  

Science.gov (United States)

Here we developed a sensitive, specific, and rapid immunochromatographic strip test for the detection of Cronobacter. Silica-coated magnetic nanoparticles were used to separate nucleic acid from Cronobacter lysate and eliminate the interference of food matrices successfully. A couple of 5'-end labeled probes, which was complementary to the 16S ribosomal DNA of Cronobacter, was used to hybridize with the nucleic acid. The hybrid product, labeled with digoxigenin on one side and biotin on the other side, was directly submitted to the immunochromatographic strip test and the anti-digoxigenin monoclonal antibody was immobilized on nitrocellulose membrane in the test line. The visualization was achieved by gold nanoparticles conjugated to streptavidin, and double red bands appearing in both test and control line indicated a positive result of the presence of Cronobacter in testing sample. The detection limit was 10(7)cfumL(-1) in pure culture. After silica-coated magnetic nanoparticles treatment, the detection limit was 10(5) and 10(6)cfumL(-1) in pure culture and powdered infant formula, respectively, and maintained stable even under the interference of 10(8)cfumL(-1)Salmonella typhimurium. Furthermore, 100 positive powdered infant formula samples spiked 10(8)cfumL(-1)Cronobacter and 20 negative samples with none bacteria were tested by the strip, and the sensitivity and specificity of the test were both as high as 100%. This approach showed promise for microbial detection concerning food safety or clinical diagnosis. PMID:24907538

Chen, Fei; Ming, Xing; Chen, XingXing; Gan, Min; Wang, BaoGui; Xu, Feng; Wei, Hua

2014-11-15

307

Effective connection of phase-separated metallic pathways under low magnetic fields in charge-ordered insulators of micropatterned perovskite manganite thin films  

International Nuclear Information System (INIS)

We investigated the probe size dependence of the electrical transport properties of perovskite manganite La0.67Ca0.33MnO3 (LCMO) films with electronic phase separation (EPS) between ferromagnetic metal and charge-ordered insulator phases. A micropatterned wire was fabricated by an excimer-laser-assisted metal organic deposition process. A patterned wire of an LCMO film with a width of 10 ?m had a higher insulator-metal transition temperature associated with the ferromagnetic transition than that of an LCMO film with a large probe size. Moreover, a low-magnetic-field magnetoresistance (LFMR) effect was observed for the micropatterned wire film; the resistivity decreased only from H perpendicular c > 0.02 T. The origin of this LFMR effect is thought to be the effective connections of the ferromagnetic metal domains between the probe contacts with small dimensions similar to the size of the phase-separated metal and insulator domains. These properties were qualitatively explained by numerical simulations of resistance variations for different probe sizes. (author)

2010-01-01

308

Rapid Fluorescent Detection of Escherichia coli K88 Based on DNA Aptamer Library as Direct and Specific Reporter Combined With Immuno-Magnetic Separation.  

Science.gov (United States)

Nucleic acid aptamers have long demonstrated the capacity to bind cells with high affinity so that they have been utilized to diagnose various important pathogens. In this study, a DNA aptamer library was on initial efforts developed to act as a specific reporter for rapid detection of enter toxigenic Escherichia coli (ETEC) K88 combined with immuno-magnetic separation (IMS). During a Whole-cell Systematic Evolution of Ligands by Exponential Enrichment (CELL-SELEX) procedure, the last selection pool against ETEC K88, which is named "DNA aptamer library" here, was selected and subsequently identified by flow cytometric analysis and confocal imaging. A K88 monoclonal antibody (mAb) with high affinity (Kaff: 1.616?±?0.033?×?10(8) M(-1)) against K88 fimbrial protein was prepared, biotinylated and conjugated to streptavidin-coated magnetic beads (MBs). After the bacteria were effectively captured and enriched from the complex sample by immuno-magnetic beads (IMBs), 5'-FITC modified aptamer library was directly bound to target cells as a specific reporter for its detection. The detection system showed clearly high specificity and sensitivity with the detection limit of 1.1?×?10(3) CFU/ml in pure culture and 2.2?×?10(3) CFU/g in artificially contaminated fecal sample. The results also indicated that fluorophore-lablled DNA aptamer library as specific reporter could generate more reliable signals than individual aptamer with best affinity against target cells and implied it would have great applied potential in directly reporting bacteria from complex samples combined with IMS technology. PMID:24763818

Peng, Zhihui; Ling, Min; Ning, Yi; Deng, Le

2014-07-01

309

Coupling of magnetic field and lattice strain and its impact on electronic phase separation in La0.335Pr0.335Ca0.33MnO3/ferroelectric crystal heterostructures  

International Nuclear Information System (INIS)

Phase-separated La0.335Pr0.335Ca0.33MnO3 films were epitaxially grown on (001)- and (111)-oriented ferroelectric single-crystal substrates. Upon poling along the [001] or [111] direction, dramatic decrease in resistance, up to 99.98%, and complete melting of the charge-ordered phase were observed, caused by poling-induced strain rather than accumulation of electrostatic charge at interface. Such poling-induced strain effects can be effectively tuned by a magnetic field and mediated by electronic phase separation. In particular, our findings show that the evolution of the strength of electronic phase separation against temperature and magnetic field can be determined by measuring the strain-tunability of resistance [(?R/R)strain] under magnetic fields

2013-12-23

310

Magnetic state of the structural separated anion-deficient La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} manganite  

Energy Technology Data Exchange (ETDEWEB)

The results of neutron diffraction studies of the La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} compound and its behavior in an external magnetic field are stated. It is established that in the 4-300 K temperature range, two structural perovskite phases coexist in the sample, which differ in symmetry (groups R3-bar c and I4/mcm). The reason for the phase separation is the clustering of oxygen vacancies. The temperature (4-300 K) and field (0-140 kOe) dependences of the specific magnetic moment are measured. It is found that in zero external field, the magnetic state of La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} is a cluster spin glass, which is the result of frustration of Mn{sup 3+}-O-Mn{sup 3+} exchange interactions. An increase in external magnetic field up to 10 kOe leads to fragmentation of ferromagnetic clusters and then to an increase in the degree of polarization of local spins of manganese and the emergence of long-range ferromagnetic order. With increasing magnetic field up to 140 kOe, the magnetic ordering temperature reaches 160 K. The causes of the structural and magnetic phase separation of this composition and formation mechanism of its spin-glass magnetic state are analyzed.

Trukhanov, S. V., E-mail: truhanov@ifttp.bas-net.by; Trukhanov, A. V. [Scientific Practical Materials Research Centre of NAS of Belarus (Belarus); Vasiliev, A. N. [Moscow State University (Russian Federation); Balagurov, A. M. [Joint Institute for Nuclear Research (Russian Federation); Szymczak, H. [Institute of Physics, PAS (Poland)

2011-11-15

311

Magnetic-field-induced transition from metastable spin glass to possible antiferromagnetic-ferromagnetic phase separation in $Cd_{0.5}Cu_{0.5}Cr_2O_4$  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using ac susceptibility, dc magnetization and heat capacity measurements, we have investigated the magnetic properties of $Cd_{0.5}Cu_{0.5}Cr_2O_4$. $Cd_{0.5}Cu_{0.5}Cr_2O_4$ has an extraordinary magnetic phase including a metastable spin-glass(SG) phase at zero field, a possible phase separation scenario of AFM/FM above $\\sim 0.5T$ field, and at intermediate fields, an apparent pseudo reentrant spin-glass (RSG) plateau is observed. These phenomena are closely correlated wit...

Yan, Li-qin; Yin, Wen; Macia?, Ferran; Zhang, Jun-rong; He, Lun-hua; Wang, Fang-wei

2008-01-01

312

Magnetic and micellar effects on photoreactions. 2. Magnetic isotope effects on quantum yields and magnetic field effects on separation efficiency. Correlation of 13C-enrichment parameters with quantum yield measurements  

International Nuclear Information System (INIS)

The quantum yields (PHI) and 13C isotopic enrichment parameters (?) for photolysis of dibenzyl ketone in aqueous detergent solution have been measured as a function of applied magnetic field and isotopic substitution. A quantitative correlation is shown to exist betwen the magnitude of ? and quantum yield data. The mechanism of 13C enrichment and the magnetic field effects are discussed and shown to be mechanistically related

1981-07-01

313

Size-regulated group separation of CoFe2O4 nanoparticles using centrifuge and their magnetic resonance contrast properties  

Science.gov (United States)

Magnetic nanoparticle (MNP)-based magnetic resonance imaging (MRI) contrast agents (CAs) have been the subject of extensive research over recent decades. The particle size of MNPs varies widely and is known to influence their physicochemical and pharmacokinetic properties. There are two commonly used methods for synthesizing MNPs, organometallic and aqueous solution coprecipitation. The former has the advantage of being able to control the particle size more effectively; however, the resulting particles require a hydrophilic coating in order to be rendered water soluble. The MNPs produced using the latter method are intrinsically water soluble, but they have a relatively wide particle size distribution. Size-controlled water-soluble MNPs have great potential as MRI CAs and in cell sorting and labeling applications. In the present study, we synthesized CoFe2O4 MNPs using an aqueous solution coprecipitation method. The MNPs were subsequently separated into four groups depending on size, by the use of centrifugation at different speeds. The crystal shapes and size distributions of the particles in the four groups were measured and confirmed by transmission electron microscopy and dynamic light scattering. Using X-ray diffraction analysis, the MNPs were found to have an inverse spinel structure. Four MNP groups with well-selected semi-Gaussian-like diameter distributions were obtained, with measured T2 relaxivities ( r 2) at 4.7 T and room temperature in the range of 60 to 300 mM-1s-1, depending on the particle size. This size regulation method has great promise for applications that require homogeneous-sized MNPs made by an aqueous solution coprecipitation method. Any group of the CoFe2O4 MNPs could be used as initial base cores of MRI T2 CAs, with almost unique T2 relaxivity owing to size regulation. The methodology reported here opens up many possibilities for biosensing applications and disease diagnosis.

Kang, Jongeun; Lee, Hyunseung; Kim, Young-Nam; Yeom, Areum; Jeong, Heejeong; Lim, Yong Taik; Hong, Kwan Soo

2013-09-01

314

The evaluation of the influence of drying the ore before the dry high - intensity magnetic separation on the efficiency production process of blastfurnace pellets in the Siderit Ni?ná Slaná plant  

Directory of Open Access Journals (Sweden)

Full Text Available In the contribution is described the evaluation of the influence of the parameters on the input to the dry high - intensity magnetic separation (SVIMS, on the technological production process of the blastfurnace pellets in the condition of the company ?elba, a.s., o.z. Siderit Ni?ná Slaná.By the dry high - intensity magnetic separation (SVIMS separates siderite from inherent rock by the activity effect of the strong magnetic field of the electromagnets. The realisation of the dry high - intensity magnetic separation has got the effect on the technical - technological parameters, as well as on the qualitative parameters of the final product - the blastfurnace pellets.The aim of the solution of the author this article is to define the methodics, that it would permit the establishment practice to complex judges of the fall of the racionalization projects. The aim of this project it would be as first of all the total productions costs minimize, the work optimalization and the increase of the economic efficiency work of the organisation.

Kuffnerová Andrea

2001-12-01

315

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

316

Electromagnetic separator of plasma  

International Nuclear Information System (INIS)

The progress in the widespread utilization of the PVD methods is determined in many respects by the plasma quality and, therefore, the necessity of an application of plasma separators, in particular magnetic separators. One needs to note that traditional magnetic separators have a number of problems their using, namely their unwieldiness, the presence of the isolated cameras and so on. We have proposed, manufactured and investigated the simple separator of plasma that doesn't require using additional cameras. As a source of metallic plasma the standard cathode vaporizer in the installation 'BULAT 6' was in use. Plasma stream from the cathode flowed through the not protected by isolation spiral solenoid. The solenoid input (from the cathode side) was under floating potential. The solenoid output was connected to the autonomous power supply system. The solenoid was prepared with stride winding and 90 degree turn. The solenoid current was 20-90 A and the solenoid voltage with respect to the vessel (earth) was +15 V. In this case drifting charged particles could freely fly out from the interior solenoid region to its boundary. The glow of the turned flow of plasma was observed during the supplying of the cathode and the solenoid. Plasma flow was separated from the coils and extended along the axis of solenoid. One can assume that this device ensures radial electric with respect to the bulk of plasma (the diameter of the bulk of plasma is comparable with the cathode diameter), the toroidal magnetic field, produced by solenoid, was of an order of 20 Oe. Magnetic field strength was sufficient for the magnetization of electrons, but it was rather small for magnetizing the ions and charged micro-droplets. The experiments carried out with aluminum cathode on the deposition of coatings at the stainless steel substrate have shown the high effectiveness of this separator operation. Coatings without droplets were obtained also on the glass substrate with HF- displacement. (author)

2005-09-06

317

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 ?g L(-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; Zhad, Hamid Reza Lotfi; Sadeghi, Omid; Karimi, Mohammad; Najafi, Ezzatollah

2013-12-15

318

A separation mechanism of photogenerated charges and magnetic properties for BiFeO3 microspheres synthesized by a facile hydrothermal method.  

Science.gov (United States)

BiFeO(3) (BFO) microspheres were synthesized by a facile hydrothermal method. The optical absorption spectrum indicates that on site Fe(3+) crystal-field transitions and the charge transfer excitations can be observed. Magnetic measurements show a spin-glass behavior and room temperature weak ferromagnetism. The surface photovoltage spectroscopy of the BFO shows two response peaks centered at about 370 and 400 nm, respectively. Under an ambient atmosphere, the maximum surface photovoltage of the BFO reaches 180 ?V with the bias (+2 V) and is three times larger than that with zero bias. It is found that the surface photovoltage response intensity increases with an increase in applied bias, regardless of positive or negative bias. It is suggested that the surface photovoltaic properties are related to both the depolarization field owing to ferroelectric polarization and the build-in electric field due to the Schottky barrier. The micro-process and the physical mechanism of the separation of photogenerated charges for BFO are fully explained. PMID:22588092

Zheng, Haiwu; Liu, Xiangyang; Diao, Chunli; Gu, Yuzong; Zhang, Weifeng

2012-06-21

319

Magnetically separable Prussian blue analogue Mn?[Co(CN)?]?·nH?O porous nanocubes as excellent absorbents for heavy metal ions.  

Science.gov (United States)

The application of Prussian blue analogue (PBA) Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes as absorbents for heavy metal ions has been demonstrated. The result indicates that Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes with average diameter of 240 nm possess excellent adsorption efficiency for Pb(2+) ions (94.21% at initial Pb(2+) concentration of 10 mg L(-1)). Moreover, Mn(3)[Co(CN)(6)](2)·nH(2)O porous nanocubes can also show high adsorption efficiency on heavy metal ions even in a strong acidic solution due to its chemical stability. Notably, an external magnet could be used to accelerate the separation of Mn(3)[Co(CN)(6)](2)·nH(2)O from the treated solution. It is suggested that the high adsorption efficiency may derive from the large surface area, M(3)(II)[M(III)(CN)(6)](2)·nH(2)O porous framework structure and affinity between polarizable ?-electron clouds of the cyanide bridges and heavy metals ions. PMID:21863190

Hu, Lin; Mei, Ji-Yang; Chen, Qian-Wang; Zhang, Ping; Yan, Nan

2011-10-01

320

Quantification of the magnetization-transfer contrast effect: can it yield additional information in differentiation of musculoskeletal lesions particularly in separation of benign from malignant lesions  

International Nuclear Information System (INIS)

Purpose: To investigate the potential information of the amount of magnetization-transfer effect in musculoskeletal lesions and to compare MT ratios from benign and malignant musculoskeletal lesions. Material and Method: 49 patients with malignant tumors (3 osteosarcoma, 3 malignant fibrous histiocytoma, 4 chondrosarcoma, 2 Ewing sarcomas) and benign lesions (8 chondroma, 2 fibrous dysplasia, 3 osteoid-osteoma, 6 ganglion cyst, 3 cyst, 3 osteomyelitis, 4 tendinitis, 3 rotator cuff tear, 5 scar tissue) were scanned using routine MRI protocols including T1- and T2-weighted spin echo as well as T2*-weighted gradient echo (FFE) sequences at 1.5 Tesla (ACS II, Philips Medical). Additionally MTC images were generated by combining the FFE sequence and the off-resonance MT technique (-1500 Hz off-resonance frequency, 1770 flip angle and 50 ms pulse duration). MT ratios were calculated as SIo-SIm/SIo. Results: The MT ratio of benign lesions was 26±15%, that of malignant lesions was 22±6%. The difference was statistically not significant. As expected muscle showed a high MT ratio of 50±8%. Scar tissue demonstrated an MT ratio of 39±16% which was significantly higher than the tumor MT ratios. Conclusion: MTC (MT ratios) failed to show significant differences between benign and malignant lesions as was expected due to basic differences in cellularity, rate of mitosis and chromatin content. MTC might however gain more importance in separating scar tissue from recurrent tumor in the future. (orig.)

1999-12-01

 
 
 
 
321

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

1989-06-01

322

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

323

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

324

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

325

Separated flow  

Science.gov (United States)

A brief overview of flow separation phenomena is provided. Langley has many active research programs in flow separation related areas. Three cases are presented which describe specific examples of flow separation research. In each example, a description of the fundamental fluid physics and the complexity of the flow field is presented along with a method of either reducing or controlling the extent of separation. The following examples are discussed: flow over a smooth surface with an adverse pressure gradient; flow over a surface with a geometric discontinuity; and flow with shock-boundary layer interactions. These results will show that improvements are being made in the understanding of flow separation and its control.

Sellers, W. L., III; Dunham, R. E., Jr.; Goodman, W. L.; Howard, F. G.; Margason, R. J.; Rudy, D. H.; Rumsey, C. L.; Stough, H. P., III; Thomas, J. L.

1986-12-01

326

An adapted ImmunoMagnetic cell separation method for use in quantification of Escherichia coli O157:H7 from bovine faeces.  

Science.gov (United States)

Detection of Escherichia coli O157:H7 organisms in food, clinical or environmental samples is necessary for diagnosis of infection and epidemiological investigations. However, this pathogen may be present in low numbers and difficult to identify among high numbers of other background bacteria. In order to increase the sensitivity of culture- and PCR detection, pre-enrichment of E. coli O157:H7 in broth culture combined with ImmunoMagnetic cell Separation (IMS) is routinely employed. These methods, although able to detect levels as low as 2 cfu/g (from 10 to 25 g samples), are qualitative detection strategies only. If the actual numbers of E. coli O157:H7 are to be quantified, growth enrichment must be excluded and the organisms isolated directly from the sample of interest. Such quantification is necessary, for example, to determinate contamination levels on beef carcasses and for determination of bacterial numbers in in vivo gene expression studies. In the present study, it was not possible to recover organisms from bovine faecal suspensions using the customary IMS system and so a range of alternative buffers and other paramagnetic beads was tested. Combination of a 6.2-microm diameter bead with a detergent-based buffer gave optimal recovery of E. coli O157:H7 organisms from faecal suspensions. This system was validated for recovery of E. coli O157:H7 by comparing it with that obtained with the standard Dynabeads IMS protocol, using both the traditional broth enrichment method and a quantitative detection approach. We conclude that a 6.2-microm diameter Aureon bead can be used for quantitative isolation of E. coli O157:H7 directly from bovine faeces and, for this purpose, is preferred to the 2.8-microm diameter Dynal bead. PMID:12609717

Parham, Nick; Spencer, Janice; Taylor, David; Ternent, Helen; Innocent, Giles; Mellor, Dominic; Roberts, Mark; Williams, Alun

2003-04-01

327

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

328

MAGNET  

CERN Multimedia

  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

329

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

330

MAGNET  

CERN Multimedia

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

331

Diamagnetic Particle Separation in Ferrofluid Microflows  

Science.gov (United States)

Particle separation is important for a wide range of applications. A variety of force fields have been demonstrated to separate particles in microfluidic devices. Magnetic field-induced separation is simple, cheap, and free of fluid heating issues that accompany electric, acoustic, and optical methods. We develop a novel magnetic particle separation method in a curved microchannel with a nearby permanent magnet. This method is capable of separating both magnetic and nonmagnetic particles by size. It is based on the dependence of particle magnetophoresis on the particle size and the particle's distance from the magnet. We present in this talk a continuous separation of 3 ?m- and 5 ?m-diameter polystyrene particles in a ferrofluid flow without magnetic and fluorescent labeling. We also develop a numerical model to simulate the particle separation process.

Xuan, Xiangchun; Liang, Litao

2011-11-01

332

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

333

Isotope separation  

International Nuclear Information System (INIS)

A method of isotope separation is described which involves the use of a laser photon beam to selectively induce energy level transitions of an isotope molecule containing the isotope to be separated. The use of the technique for "2"3"5U enrichment is demonstrated. (UK)

1979-01-01

334

Isotope separation  

International Nuclear Information System (INIS)

Isotope separation is today one of the most actively pursued areas of laser application. Many isotopes have been separated successfully to date in laboratory experiments, but much still remains to be done to extend the results to an industrial scale, where the process is optimized for economy. The authors consider what has been done so far to improve uranium enrichment using UF6. (Auth.)

1981-01-01

335

Centrifugal separators  

International Nuclear Information System (INIS)

Following specific development tests, centrifugal separators, being very compact, and having high efficiency can be applied to various flow conditions. In the PWR secondary circuit, they are used both in steam generators, as the first separation stage, and for turbine exhausts and extraction line applications

1986-01-01

336

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

337

MAGNET  

CERN Multimedia

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.

338

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

339

MAGNET  

CERN Multimedia

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

340

Cluster glass properties and magnetic phase separation studies of NdxBi0.5-xSr0.5MnO3 (x = 0.1, 0.2, 0.3 and 0.4)  

International Nuclear Information System (INIS)

The crystal structure, dc and ac magnetic susceptibility, electron spin resonance and magnetoresistive behavior of NdxBi0.5-xSr0.5MnO3 (x = 0.1, 0.2, 0.3 and 0.4) compounds are studied. The Rietveld analysis of the XRD data shows that the samples crystallize in an orthorhombic perovskite structure, with Pbnm space group for x = 0.1 and 0.2 and Imma space group for x = 0.4 and 0.3. Magnetic studies reveal that substituting Bi with Nd collapses the robust charge ordered AFM state of Bi0.5Sr0.5MnO3 to an inhomogeneous magnetic state. As Nd concentration increases there is a gradual appearance of cluster glass behavior. ESR studies reveal that the NBSMO system phase separates into ferromagnetic and antiferromagnetic regions below the transition temperature.

2009-05-13

 
 
 
 
341

Electronic phase separation and magnetic order in the cobalt doped RFe{sub 2-x}Co{sub x}As{sub 2} (R=Sr, Eu) iron pnictide superconductors  

Energy Technology Data Exchange (ETDEWEB)

We have investigated the magnetic and superconducting properties of RFe{sub 2-x}Co{sub x}As{sub 2} with R=Sr, Eu and 0{<=}x{<=}0.4 by means of muon spin relaxation ({mu}{sup +}SR) and Moessbauer spectroscopy. Under ambient pressure the antiferromagnetic ordering temperature, T{sub N} of SrFe{sub 2-x}Co{sub x}As{sub 2} decreases with increasing Co-doping. However, T{sub N} 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, EuFe{sub 2-x}Co{sub x}As{sub 2} 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.

Kwadrin, A.; Maeter, H.; Klauss, H.H. [Institut fuer Festkoerperphysik, TU Dresden (Germany); Luetkens, H.; Khasanov, R.; Amato, A. [Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, Villigen (Switzerland); Kraken, M.; Litterst, J. [Institut fuer Physik der Kondensierten Materie, TU Braunschweig (Germany); Jesche, A.; Leithe-Jasper, A.; Rosner, H.; Schnelle, W.; Geibel, C. [Max-Planck-Institut fuer Chemische Physik Fester Stoffe, Dresden (Germany)

2009-07-01

342

Dust separator  

Energy Technology Data Exchange (ETDEWEB)

A construction for a dust separator is proposed, containing a body, tangential inlet connection pipe, central exhaust connection pipe with a conical insert, located in the body of the dust separator, diffuser mounted concentrically with the conical insert in the exhaust connection pipe, and a conical flow deflector located on the axis of the diffuser. For increasing the collection efficiency by changing the structure of the flow, the flow deflector is equipped with rotatable vanes and is installed with the possibility for rotation. The flow deflector, the conical insert in the exhaust connection pipe, and the diffuser are mounted with the possibility for vertical displacement of the dust separator.

Lazarenko, V.I.

1980-06-30

343

Extraction of 3D field maps of magnetic multipoles from 2D surface measurements with applications to the optics calculations of the large-acceptance superconducting fragment separator BigRIPS  

International Nuclear Information System (INIS)

Highlight: • Novel practical method to extract 3D magnetic field maps from 2D surface measurements. • Full 3D maps of multipoles are numerically deduced using Fourier transforms. • Only one component on a cylindrical surface is needed for the 2D field measurements. • Successfully applied to field measurements and optics calculations of BigRIPS separator. -- Abstract: The fringing fields of magnets with large apertures and short lengths greatly affect ion-optical calculations. In particular, for a high magnetic field where the iron core becomes saturated, the effective lengths and shapes of the field distribution must be considered because they change with the excitation current. Precise measurement of the three-dimensional magnetic fields and the correct application of parameters in the ion-optical calculations are necessary. First we present a practical numerical method of extracting full 3D magnetic field maps of magnetic multipoles from 2D field measurements of the surface of a cylinder. Using this novel method, we extracted the distributions along the beam axis for the coefficient of the first-order quadrupole component, which is the leading term of the quadrupole components in the multipole expansion of magnetic fields and proportional to the distance from the axis. Higher order components of the 3D magnetic field can be extracted from the leading term via recursion relations. The measurements were done for many excitation current values for the large-aperture superconducting triplet quadrupole magnets (STQs) in the BigRIPS fragment separator at the RIKEN Nishina Center RI Beam Factory. These distributions were parameterized using the Enge functions to fit the fringe field shapes at all excitation current values, so that unmeasured values are interpolated. The extracted distributions depend only on the position along the beam axis, and thus the measured three-dimensional field can easily be parameterized for ion-optical calculations. We implemented these parameters in the ion-optical calculation code COSY INFINITY and realized a first-order calculation that incorporates the effect of large and varying fringe fields more accurately. We applied the calculation to determine the excitation current settings of the STQs to realize various optics modes of BigRIPS and the effectiveness of this approach has been demonstrated

2013-12-15

344

Isotopic separation  

International Nuclear Information System (INIS)

This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of "2"3"5U from other uranium isotopes including "2"3"8U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF_6 molecules in HBr molecules so as to collapse the V_3 vibrational mode of the UF_6 molecule the "2"3"5UF_6 molecules are selectively excited to promote reduction of UF_6 molecules containing "2"3"5U and facilitate separation. (UK)

1979-01-01

345

Sutures - separated  

Science.gov (United States)

... a sign of pressure within the skull ( increased intracranial pressure ). Separated sutures may be associated with bulging fontanelles . If intracranial pressure is increased a lot, there may be large ...

346

Separation technologies  

International Nuclear Information System (INIS)

The chemical process industries (CPI), including the petroleum and chemical industries, consume the energy equivalent of about three million barrels of crude oil per day - this translates to 27% of industrial energy consumption in the U.S. (excluding raw materials). This paper discusses separation processes which recover and purify products account for over 40% of CPI energy demand. Separation processes include removal of impurities from raw materials, of products and by-products from reactor crude, and of containments from water and air effluents. Examples of such separation processes include absorption, adsorption, ion exchange, chromatography, crystallization, distillation, drying, electrodialysis, electrolytic processes, evaporation, extraction, filtration, flotation, membranes, and stripping. Because distillation is the most widely used separation process, we will focus on it and its alternatives, adsorption, and membrane processes

1992-03-01

347

Stereoisomers Separation  

Science.gov (United States)

The use of capillary electrophoresis for enantiomer separation and optical purity determination is presented. The contents start with basic information about the nature of stereoizomers and the mechanism of enantioseparation using capillary electrophoresis techniques. The molecules to be separated show identical chemical structure and electrochemical behavior. Therefore, the chiral recognition of enantiomers is possible only by bonding to chiral selector and the separation based on very small differences in complexation energies of diastereomer complexes formed. This method is useful for this purpose due to the fact that different compounds can be used as chiral selectors. The mostly used chiral selectors like cyclodextrins, crown ethers, chiral surfactants, macrocyclic antibiotics, transition metal complexes, natural, and synthetic polymers and their application for this purpose is also discussed. Finally, examples of practical applications of electromigration techniques for enantiomers separation and determination are presented.

Wieczorek, Piotr

348

Separations chemistry  

International Nuclear Information System (INIS)

Results of studies on the photochemistry of aqueous Pu solutions and the stability of iodine in liquid and gaseous CO_2 are reported. Progress is reported in studies on: the preparation of macroporous bodies filled with oxides and sulfides to be used as adsorbents; the beneficiation of photographic wastes; the anion exchange adsorption of transition elements from thiosulfate solutions; advanced filtration applications of energy significance; high-resolution separations; and, the examination of the separation agents, octylphenylphosphoric acid (OPPA) and trihexyl phosphate (THP)

1976-02-01

349

MAGNET  

CERN Multimedia

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

350

MAGNET  

CERN Multimedia

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

351

Influence of phase separation on the low-field magnetic properties of La1-xSrxMn1-yFeyO3  

International Nuclear Information System (INIS)

The magnetic properties of ceramic La1-xSrxMn1-yFeyO3 samples with x = 0.3 and y = 0.15-0.25 are investigated in magnetic fields of B = 10.103 G at a temperature T between 5-310 K. A ferromagnetic transition at TC, decreasing considerably with y, is accompanied with strong magnetic irreversibility at B = 10 G. The critical behavior of ? (T) ? (T/TC - 1)-? is governed at y = 0.15-0.20 by the percolative (? ? 1.8) and Heisenberg ((? ? 1.4) spin systems. (authors)

2010-01-01

352

EFFICIENCY OF METAL SCRAP SEPARATION IN EDDY CURRENT SEPARATOR  

Directory of Open Access Journals (Sweden)

Full Text Available Eddy-current separation is most often method used for the recovery of non-ferrous metals (Al, Cu, Zn, Pb from solid wastes and also for separating non-ferrous metals from each other. The feed material comes to rotary drum and magnetic field by belt conveyer. The changing magnetic field induce eddy currents in conductive (metallic particles. Because interaction between this currents and the magnetic field electrodynamic forces will act on conductive particles. Therefore the trajectories of conductive particles will be different from the trajectories of the non-conductive ones. Separation is a result of the combined actions of several forces (electrodynamic, gravitational and frictional. The paper presents results of aluminium recovery from mixture of metallic particles in eddy current separator. Testing were conducted under field condition. Results shows that is possible achieve recovery of 99 % and concentrate quality of 89 % of aluminium.

Ivan Sobota

2008-12-01

353

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

354

Long-scale phase separation versus homogeneous magnetic state in (La1-yPry)0.7Ca0.3MnO3: A neutron diffraction study  

International Nuclear Information System (INIS)

The magnetic structure of the series (La1-yPry)0.7Ca0.3MnO3 for y from 0.5 to 1.0 has been studied by neutron powder diffraction in the temperature range from 10 to 293 K and in external magnetic fields up to 4 T. The phase diagram has a border region of concentrations 0.6?y?0.8 separating the homogeneous ferromagnetic (FM) metallic and canted antiferromagnetic (AFM) insulating states. In this region the low-temperature magnetic state is macroscopically (>103 A) separated into AFM and FM phases. The FM phase has a small noncollinearity, presumably due to interfaces to the AFM phase. The macroscopical clusters can be induced by disorder on the carrier's hopping amplitude caused by natural dispersion of the A cation radius near the metal-insulator transition around y=0.7. For the concentrations y?0.9 the long-range ordered magnetic state is homogeneous with a canted AFM structure. The total long-range ordered magnetic moment of the Mn ion shows a steplike decrease from ?Mn=3.4?B to 2.5?B as a function of Pr concentration at the transition to a homogeneous canted antiferromagnetic (CAF) state. The spatial inhomogeneities can still be present for y?0.9, according to the reduced ?Mn value, but the Mn spins between the homogeneously CAF-ordered moments have to be either short-range ordered or paramagnetic. In addition, a ferromagnetic contribution of the Pr moments parallel to the ferromagnetic component of Mn moments is found for y>0.6. The moment of Pr scales with the ferromagnetic Mn moment rather than with the Pr concentration and thus presumably induced by Mn

2001-07-01

355

Centrifugal separator  

International Nuclear Information System (INIS)

The separation efficiency of a centrifugal gas separator is heightened by a rotary drum of a bottomed double-walled construction which allows a gas mixture to be admitted into the drum interior circumferentially rather than axially through two or more holes perforated into the central portion of the inner wall thereof. The inner and outer walls of the drum define a space that connects with the holes and which is further communicated with a gas mixture storage tank via a passage provided in the upper end cap and a gas inlet tube axially contained within a drive shaft movably supported by a damper and integrally joined to the upper end cap. Both end caps are perforated with a plurality of orifices and the entire mechanism is enclosed by a bottomed cylindrical vacuum tank provided with outlet pipes for discharging the separated gases obtained through the orifices. Circumferentially admitting the gas mixture through the aforementioned holes during rotation cancels gas flow in the radial direction, enables the angular velocity of the gas mixture to exceed that of the velocity of the drum and enhances convection currents, whereby the separation efficiency surpasses that of the centrifugal separators of the former art. (Owens, K. J.)

1970-01-01

356

Separation system  

International Nuclear Information System (INIS)

A disposal container is described for use in disposal of radioactive waste materials consisting of: top wall structure, bottom wall structure, and circumferential side wall structure interconnecting the top and bottom wall structures to define an enclosed container, separation structure in the container adjacent the inner surface of the side wall structure for allowing passage of liquid and retention of solids, inlet port structure in the top wall structure, discharge port structure at the periphery of the container in communication with the outer surface of the separation structure for receiving liquid that passes through the separation structure, first centrifugally actuated valve structure having a normal position closing the inlet port structure and a centrifugally actuated position opening the inlet port structure, second centrifugally actuated valve structure having a normal position closing the discharge port structure and a centrifugally actuated position opening the discharge port structure, and coupling structure integral with wall structure of the container for releasable engagement with centrifugal drive structure

1986-01-01

357

Minerals separator  

Energy Technology Data Exchange (ETDEWEB)

A minerals separator comprising a body having a surface having the form of the inside of a spiralinder, which may be tapered, arranged when rotating about its axis to have a force acting axially along it, means for rotating the body about the axis of the spiralinder to apply a centrifugal force exceeding g to said surface, means for applying perturbations to the body, means for batchwise applying a slurry and means for batchwise applying washing liquid to a spiral line on the inside of the spiralinder, and means for collecting separately fractions of different mobilities axially along the spiralinder.

Mozley, R.H.

1990-06-13

358

Battery separator  

Energy Technology Data Exchange (ETDEWEB)

A composition suitable for use as a battery separator comprises a substantially homogeneous mixture of a copolymer of ethylene and acrylic acid having from 10 to 23 mole percent acrylic acid therein and a melt index of from about 0.1 to 5 in combination with a copolymer of ethylene and acrylic acid having at least 25 mole percent acrylic acid therein and having a melt index of at least about 10. The present invention is further directed to a process of forming a sheet product from the subject composition and the use of the formed product as a battery separator.

Wszolek, W.R.; Lundquist, J.T. Jr.

1984-02-28

359

Isotope separation  

Energy Technology Data Exchange (ETDEWEB)

An isotope separation apparatus comprises a plurality of independent developing units, each comprising 2 to 20 adsorbent packed columns forming a continuous developing circuit or passageway, and the developing units are connected to at least one common main pipe for supplying an isotope mixture solution, a regenerating agent solution, or an eluent solution. Also, in a further embodiment the developing units are connected to common liquid-discharge main pipes. The separation or concentration of isotopes such as uranium isotopes, nitrogen isotopes, boron isotopes, etc., is performed by continuously developing the isotope mixture solution passed through the individual adsorbent-packed columns successively in each developing units.

Inada, K.; Miyake, T.; Ogawa, N.; Takeda, K.

1981-11-24

360

Isotope separation  

Energy Technology Data Exchange (ETDEWEB)

An isotope separation apparatus comprises of a plurality of independent developing units, each comprising 2 to 20 adsorbent packed columns forming a continuous developing circuit or passageway, and the developing units are connected to at least one common main pipe for supplying an isotope mixture solution, a regenerating agent solution, or an eluent solution. Also, in a further embodiment the developing units are connected to common liquid-discharge main pipes. The separation or concentration of isotopes such as uranium isotopes, nitrogen isotopes, boron isotopes, etc., is performed by continuously developing the isotope mixture solution which passes through the individual adsorbent-packed columns successively in each developing units.

Inada, K.; Miyake, T.; Ogawa, N.; Takeda, K.

1981-07-28

 
 
 
 
361

Recent Advances in Magnetic Processes.  

Science.gov (United States)

Various magnetic separation processes including magnetic coagulation/sedimentation, magnetic filtration, magnetic ion exchange, and magnetite addition are reviewed. Their general theories and principles are described. Their various applications in water a...

M. Krofta L. K. Wang B. C. Wu F. Rogalla

1985-01-01

362

Magnetic fractionation of magnetic fluids  

Energy Technology Data Exchange (ETDEWEB)

The properties of magnetic nanoparticles in magnetic fluids often exhibit a broad distribution, so in many applications only a small number of particles contribute to the desired magnetic effect. In order to optimize magnetic fluids for applications, preference is given to methods that separate the nanoparticles on the basis of their magnetic properties. Therefore, a magnetic method has been developed for the fractionation of magnetic fluids into two or more fractions. A common magnetic fluid was fractionated by this method. Magnetic and nonmagnetic properties of the fractions obtained and the original sample were measured. In addition to measurement of their magnetization curves they were also investigated by magnetic resonance and magnetorelaxometry, two biomedical applications of magnetic nanoparticles. The influence of the ion concentration of the washing solutions on the magnetic fractionation was additionally tested. The magnetic fractions have distinctly better magnetic properties than the original samples and are therefore especially suited for applications. Furthermore, the results indicate that the magnetic method fractionates the particles in accordance with their magnetic moment and that it has good recovery as well as reproducibility. Finally, magnetic fractionation is compared with other fractionation techniques.

Rheinlaender, Thomas E-mail: th.rheinlaender@gmx.net; Koetitz, Roman; Weitschies, Werner; Semmler, Wolfhard

2000-09-01

363

Magnetic fractionation of magnetic fluids  

International Nuclear Information System (INIS)

The properties of magnetic nanoparticles in magnetic fluids often exhibit a broad distribution, so in many applications only a small number of particles contribute to the desired magnetic effect. In order to optimize magnetic fluids for applications, preference is given to methods that separate the nanoparticles on the basis of their magnetic properties. Therefore, a magnetic method has been developed for the fractionation of magnetic fluids into two or more fractions. A common magnetic fluid was fractionated by this method. Magnetic and nonmagnetic properties of the fractions obtained and the original sample were measured. In addition to measurement of their magnetization curves they were also investigated by magnetic resonance and magnetorelaxometry, two biomedical applications of magnetic nanoparticles. The influence of the ion concentration of the washing solutions on the magnetic fractionation was additionally tested. The magnetic fractions have distinctly better magnetic properties than the original samples and are therefore especially suited for applications. Furthermore, the results indicate that the magnetic method fractionates the particles in accordance with their magnetic moment and that it has good recovery as well as reproducibility. Finally, magnetic fractionation is compared with other fractionation techniques

2000-09-01

364

A simple method to recover Norovirus from fresh produce with large sample size by using histo-blood group antigen-conjugated to magnetic beads in a recirculating affinity magnetic separation system (RCAMS).  

Science.gov (United States)

Human norovirus (NoV) outbreaks are major food safety concerns. The virus has to be concentrated from food samples in order to be detected. PEG precipitation is the most common method to recover the virus. Recently, histo-blood group antigens (HBGA) have been recognized as receptors for human NoV, and have been utilized as an alternative method to concentrate human NoV for samples up to 40 mL in volume. However, to wash off the virus from contaminated fresh food samples, at least 250 mL of wash volume is required. Recirculating affinity magnetic separation system (RCAMS) has been tried by others to concentrate human NoV from large-volume samples and failed to yield consistent results with the standard procedure of 30 min of recirculation at the default flow rate. Our work here demonstrates that proper recirculation time and flow rate are key factors for success in using the RCAMS. The bead recovery rate was increased from 28% to 47%, 67% and 90% when recirculation times were extended from 30 min to 60 min, 120 min and 180 min, respectively. The kinetics study suggests that at least 120 min recirculation is required to obtain a good recovery of NoV. In addition, different binding and elution conditions were compared for releasing NoV from inoculated lettuce. Phosphate-buffered saline (PBS) and water results in similar efficacy for virus release, but the released virus does not bind to RCAMS effectively unless pH was adjusted to acidic. Either citrate-buffered saline (CBS) wash, or water wash followed by CBS adjustment, resulted in an enhanced recovery of virus. We also demonstrated that the standard curve generated from viral RNA extracted from serially-diluted virus samples is more accurate for quantitative analysis than standard curves generated from serially-diluted plasmid DNA or transcribed-RNA templates, both of which tend to overestimate the concentration power. The efficacy of recovery of NoV from produce using RCAMS was directly compared with that of the PEG method in NoV inoculated lettuce. 40, 4, 0.4, and 0.04 RTU can be detected by both methods. At 0.004 RTU, NoV was detectable in all three samples concentrated by the RCAMS method, while none could be detected by the PEG precipitation method. RCAMS is a simple and rapid method that is more sensitive than conventional methods for recovery of NoV from food samples with a large sample size. In addition, the RTU value detected through RCAMS-processed samples is more biologically relevant. PMID:21546111

Tian, Peng; Yang, David; Mandrell, Robert

2011-06-30

365

MAGNET  

CERN Multimedia

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

366

MAGNET  

CERN Multimedia

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

367

MAGNET  

CERN Document Server

Maintenance work and consolidation activities on the magnet cryogenics and its power distribution are progressing according to the schedules. The manufacturing of the two new helium compressor frame units has started. The frame units support the valves, all the sensors and the compressors with their motors. This activity is subcontracted. The final installation and the commissioning at CERN are scheduled for March–April 2014. The overhauls of existing cryogenics equipment (compressors, motors) are in progress. The reassembly of the components shall start in early 2014. The helium drier, to be installed on the high-pressure helium piping, has been ordered and will be delivered in the first trimester of 2014. The power distribution for the helium compressors in SH5 on the 3.3kV network is progressing. The 3.3kV switches, between each compressor and its hot spare compressor, are being installed, together with the power cables for the new compressors. The 3.3kV electrical switchboards in SE5 will ...

Benoit Curé

2013-01-01

368

Chemical separations  

International Nuclear Information System (INIS)

This volume collects papers presented at a conference on chemical separation. Topics include: field-flow fractionation, chromatography, electrophoresis, solvent extraction in metals recovery, extraction of uranium and plutonium from nitric acid, modeling of flow fields in oscillating droplets, inclusion, and membrane processes

1986-04-15

369

Magnetic study of CaMn{sub 0.96}Mo{sub 0.04}O{sub 3}, canting vs. phase separation  

Energy Technology Data Exchange (ETDEWEB)

CaMn{sub 0.96}Mo{sub 0.04}O{sub 3} is an example of Mn{sup 4+} rich perovskite manganites, which exhibits a net ferromagnetic component at low temperature, observed by dc magnetization and ac susceptibility. To characterize the magnetic state of this compound, neutron powder diffraction was carried out in the 2-400 K temperature range, showing that it is necessary to use three components (ferromagnetic and G- and A-type antiferromagnetic) to describe it. This particular state is in agreement with the unusual magnetic behaviour observed by macroscopic measurements and is compared to the one observed for manganites with similar Mn valence but obtained by A-site substitution.

Martin, C. [Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 Boulevard du Marechal Juin, 14050 CAEN Cedex (France)], E-mail: christine.martin@ensicaen.fr; Miclau, M.; Hebert, S. [Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 Boulevard du Marechal Juin, 14050 CAEN Cedex (France); Giot, M. [Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 Boulevard du Marechal Juin, 14050 CAEN Cedex (France) and LLB (CEA-CNRS), CEA/Saclay, 91191 GIF SUR YVETTE Cedex (France); Maignan, A. [Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 Boulevard du Marechal Juin, 14050 CAEN Cedex (France); Andre, G.; Bouree-Vigneron, F. [LLB - CEA-CNRS, CEA/Saclay, 91191 GIF SUR YVETTE Cedex (France)

2009-12-15

370

Atomic and magnetic structures, phase separation, and unconventional superexchange interactions in Sr2GaMnO5+x (02GaMn(O,F)6  

International Nuclear Information System (INIS)

Layered brownmillerite-type manganese oxides, Sr2GaMnO5+x with mixed Mn3+/ Mn4+ valence, are studied by neutron powder diffraction. The type of magnetic order is controlled both by the structure of the non-magnetic GaO1+x buffer layer and by the orbital configuration of Mn. In Sr2GaMn(O,F)6, the Mn-valence can be varied while all anion positions in the buffer layer are completely filled. We present the crystal and magnetic structures for the end members of the family (x=0 and 0.5), for an intermediate composition (x=0.41), and for Sr2GaMnO4.8F1.2 with Mn-valence +3.8

2004-07-15

371

Rapid magnetophoretic separation of microalgae.  

Science.gov (United States)

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 chaining is observed for nanorod-tagged Chlorella sp. which eventually fosters the formation of elongated cell clusters. PMID:22438107

Lim, Jit Kang; Chieh, Derek Chan Juinn; Jalak, Selah A; Toh, Pey Yi; Yasin, Nur Hidayah Mat; Ng, Bee Wah; Ahmad, Abdul Latif

2012-06-11

372

The dynamics of magnetization in phase separated manganite around half doping: a case study for Pr$_{0.5}$Sr$_{0.5}$Mn$_{0.925}$Ga$_{0.075}$O$_{3}$  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate the dynamics of magnetization in the phase separated (PS) state after introducing the quenched disorder at the Mn-site of a manganite around half doping. The compound, Pr$_{0.5}$Sr$_{0.5}$Mn$_{0.925}$Ga$_{0.075}$O$_{3}$, exhibits PS with the coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) clusters where the size of the FM clusters is substantially reduced due to the disorder introduced by nonmagnetic Ga substitution. At low temperature, the syste...

Pramanik, A. K.; Banerjee, A.

2010-01-01

373

Isotope separation  

International Nuclear Information System (INIS)

A method of separating at least one component of an isotope mixture from the remaining component(s) of that mixture is claimed which comprises irradiating the mixture in vapour form with a pulsed beam of electromagnetic radiation. The beam has the following properties: a bandwidth not greater than the minimum isotope shift in the spectrum of the isotope mixture, a mean frequency such as to excite a plurality of molecules of the isotope mixture, an intensity such that absorption reaches the range of saturation for those molecules of the components to be separated from the isotope mixture having absorption frequencies within a set zone, and a pulse period less than the rotation relaxation time of the excited molecules

1979-01-01

374

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

Energy Technology Data Exchange (ETDEWEB)

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) {proportional_to} 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.)

Shaibu, B.S.; Reddy, M.L.P. [Chemical Sciences Div., Regional Research Lab. (CSIR), Thiruvananthapuram (India); Prabhu, D.R.; Kanekar, A.S.; Manchanda, V.K. [Radiochemistry Div., B.A.R.C. Trombay, Mumbai (India)

2006-07-01

375

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

376

Isotope separation  

International Nuclear Information System (INIS)

In the separation of short-lived isotopes for medical usage, a solution containing sup(195m)Hg is contacted with vicinal dithiol cellulose which adsorbs and retains the sup(195m)Hg. sup(195m)Au is eluted from the vicinal dithiol cellulose by using a suitable elutant. The sup(195m)Au arises from the radioactive decay of the sup(195m)Hg. The preferred elutant is a solution containing CN"- ion. (author)

1982-01-01

377

Component Separations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-...

Heller, Lior; Mcnichols, Colton H.; Ramirez, Oscar M.

2012-01-01

378

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

379

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

380

Component separations.  

Science.gov (United States)

Component separation is a technique used to provide adequate coverage for midline abdominal wall defects such as a large ventral hernia. This surgical technique is based on subcutaneous lateral dissection, fasciotomy lateral to the rectus abdominis muscle, and dissection on the plane between external and internal oblique muscles with medial advancement of the block that includes the rectus muscle and its fascia. This release allows for medial advancement of the fascia and closure of up to 20-cm wide defects in the midline area. Since its original description, components separation technique underwent multiple modifications with the ultimate goal to decrease the morbidity associated with the traditional procedure. The extensive subcutaneous lateral dissection had been associated with ischemia of the midline skin edges, wound dehiscence, infection, and seroma. Although the current trend is to proceed with minimally invasive component separation and to reinforce the fascia with mesh, the basic principles of the techniques as described by Ramirez et al in 1990 have not changed over the years. Surgeons who deal with the management of abdominal wall defects are highly encouraged to include this technique in their collection of treatment options. PMID:23372455

Heller, Lior; McNichols, Colton H; Ramirez, Oscar M

2012-02-01

 
 
 
 
381

A magnetically separable photocatalyst based on nest-like ?-Fe2O3/ZnO double-shelled hollow structures with enhanced photocatalytic activity  

Science.gov (United States)

Magnetic nest-like ?-Fe2O3/ZnO double-shelled hollow nanostructures have been successfully synthesized via a multi-step process. The materials have been thoroughly characterized by different techniques. These interesting nest-like hollow nanostructures are composed of ZnO nanoflakes grown on the surface of ?-Fe2O3 hollow spheres. Importantly, these magnetic hollow nanostructures show very high visible-light photocatalytic activity for the degradation of different organic dyes including methylene blue (MB), Rhodamine-B (RhB), and methyl orange (MO). It is further demonstrated that these ?-Fe2O3/ZnO hybrid photocatalysts are highly stable and can be used repeatedly.Magnetic nest-like ?-Fe2O3/ZnO double-shelled hollow nanostructures have been successfully synthesized via a multi-step process. The materials have been thoroughly characterized by different techniques. These interesting nest-like hollow nanostructures are composed of ZnO nanoflakes grown on the surface of ?-Fe2O3 hollow spheres. Importantly, these magnetic hollow nanostructures show very high visible-light photocatalytic activity for the degradation of different organic dyes including methylene blue (MB), Rhodamine-B (RhB), and methyl orange (MO). It is further demonstrated that these ?-Fe2O3/ZnO hybrid photocatalysts are highly stable and can be used repeatedly. Electronic supplementary information (ESI) available: XRD/TEM/schematic illustration of charge transfer. See DOI: 10.1039/c1nr11114k

Liu, Yu; Yu, Le; Hu, Yong; Guo, Changfa; Zhang, Fumin; Wen (David) Lou, Xiong

2011-12-01

382

Magnetically separable Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-Ag microspheres with well-designed nanostructure and enhanced photocatalytic activity  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: An effective route has been developed to synthesize magnetic Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-Ag microspheres with well-defined core–shell nanostructure and enhanced photocatalytic activity. -- Highlights: • Controllable synthesis of core–shell structured Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-Ag magnetic nanocomposite. • The unique nanostructure of Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-Ag can improve the total photocatalytic performance. • An easy magnetically separable and recoverable process. -- Abstract: 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 Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-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 Fe{sub 3}O{sub 4}@SiO{sub 2}@TiO{sub 2}-Ag a highly efficient, recoverable, stable, and cost-effective photocatalytic system offering broad opportunities in the field of catalyst synthesis and application.

Chi, Yue [College of Material Science and Engineering, Key Laboratory of Advanced Structural Materials, Ministry of Education, Changchun University of Technology, Changchun 130012 (China); Yuan, Qing [School of Physics and Materials Engineering, Liaoning Key Lab of Optoelectronic Films and Materials, Dalian Nationalities University, Dalian 116600 (China); Li, Yanjuan; Zhao, Liang; Li, Nan [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Li, Xiaotian, E-mail: xiaotianli@jlu.edu.cn [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Yan, Wenfu [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

2013-11-15

383

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

2005-06-01

384

Application of magnetic solid phase extraction for separation and determination of aflatoxins B1 and B2 in cereal products by high performance liquid chromatography-fluorescence detection.  

Science.gov (United States)

A simple and sensitive method based on the magnetic solid phase extraction with modified magnetic nanoparticles followed by high performance liquid chromatography with fluorescence detection has been developed for extraction and determination of aflatoxins B1 (AFB1) and B2 (AFB2) in cereal products. Magnetic nanoparticle coated with 3-(trimethoxysilyl)-1-propanthiol (TMSPT) and modified with 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) was used as an antibody-free adsorbent. Under the optimal conditions, the calibration curves for AFB1 and AFB2 were linear in the ranges of 0.2-15?gL(-1) and 0.04-3?gL(-1), respectively. Detection limit was 0.041?gL(-1) for AFB1 and 0.013?gL(-1) for AFB2. The proposed method was successfully applied to the determination of AFB1 and AFB2 in spiked corn and rice samples with an average recovery of 93.5%. The results demonstrated that the developed method is simple, rapid, inexpensive, accurate and remarkably free from interference effects. PMID:24814005

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-06-01

385

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

2009-01-26

386

Fundamental tests on recovery of valuable matters from coal ash. I. ; Recovery of magnetite from coal ash by a high gradient magnetic separator. Sekitanbaichu no yukabutsu kaishu kiso shiken (dai 4 kai). I. ; Jisen ni yoru magnetite no kaishu  

Energy Technology Data Exchange (ETDEWEB)

For the purpose of recovering fly ash magnetite (FAM), contained in fly ash (FA), FAM recovery plant for the practical use was made in conceptual design, technical evaluation and economic evaluation, based on test result of two methods, ie., wet HGMS (high gradient magnetic separation)-wet LIMS (low intensity magnetic separation) and dry HGMS-wet LIMS. The conceptual design was to treat FA, 50000ton in annual quantity, and recover FAM, 7800ton and 4000ton by the wet HGMS (W method) and dry HGMS (D method), respectively. In cost per ton, FAM product was Yen 18178 and Yen 38852 by the W method and D method, respectively. The FAM can be used also as dense medium for the dense medium cleaning in the coal preparation plant. By the W method, it gives, as almost equivalent in actual selling price to the dense medium, a possibility to be put to practical use. However, because the produced quantity of FAM, also as estimated by the present study, surpasses the demand of dense medium for the coal preparation use in Japan, the FAM recovery is indispensable in purpose development of use. 2 refs., 3 figs., 6 tabs.

Murakami, T. (The Coal Mining Research Center, Tokyo (Japan))

1990-08-01

387

Effect of strain on the phase separation and devitrification of the magnetic glass state in thin films of La5/8-yPryCa3/8MnO3 (y = 0.45)  

International Nuclear Information System (INIS)

We present our study of the effect of substrate induced strain on La5/8-yPryCa3/8MnO3 (y = 0.45) thin films grown on LaAlO3, NdGaO3 and SrTiO3 substrates that show large scale phase separation. It is observed that unstrained films grown on NdGaO3 behave quite similarly to bulk material but the strained films grown on SrTiO3 show melting of the insulating phase to the metallic phase at low temperatures. However, the large scale phase separation and metastable glass-like state is observed in all the films despite differences in substrate induced strain. The measurements of resistivity as a function of temperature under a cooling and heating in unequal field (CHUF) protocol elucidate the presence of a glass-like me