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

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.

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Magnetic separation for environmental remediation  

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 separation can be achieved while producing little or no secondary waste. The authors are currently developing the magnetic roll or drum-type separator and the high gradient magnetic separator (HGMS) for applications to soil decontamination, liquid waste treatment, underground storage tank waste treatment, and chemical processing residue concentration. The magnetic roll separator is used to separate dry powder mixtures and is most effective on particles ranging from 90 to 850 microns in size. 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 the roll separator. The results with nonradioactive surrogates and radioactive materials show that over 90% extraction of the paramagnetic components can be achieved

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Environmental remediation using magnetic separation  

International Nuclear Information System (INIS)

High Gradient Magnetic Separation (HGMS) is a physical separation process that can be used to segragate materials in a mixture on the basis of magnetic susceptibility. Unlike ferromagnetic separation methods, HGMS is generally used to separate paramagnetic (slightly magnetic) materials from diamagnetic materials. Soils consist primarily of diamagnetic components. Because all uranium and plutonium compounds are paramagnetic, HGMS can be used to extract uranium and plutonium from soils. Applications of HGMS usually involves passing a slurry of the contaminated mixture through a magnetized volume. The magnetized volume is filled with a porous magnetic matrix material, such as steel wool or expanded nickel, to generate high field gradients in the magnetized working volume. Ferromagnetic and paramagnetic components of the mixture and captured on the matrix. Thus, most of the soil slurry is decontaminated and can be returned to the local environment. Preliminary results at Los Alamos with nonradiative surrogate materials show over 99% extraction of the paramagnetic components

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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

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Continuous magnetic separator and process  

Science.gov (United States)

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

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

2008-04-22

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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

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Isotope separation by magnetic fields  

International Nuclear Information System (INIS)

One of the isotopes of an element having several isotopes can be separated from the others in a dense, neutral plasma. Thus initially a neutral plasma is prepared including the element in question. This may consist of positive ions and negative electrons or alternatively of positive and negative ions, or else of a mixture of positive ions, negative ions and electrons. The plasma may then be injected into a magnetic field or may be generated in the field where more energy is imparted to a selected isotope than to the others. Finally, the isotopes are separated from each other on the basis of their differential energies. For example, the selected isotope may be given more energy than the others by stimulating it within the plasma at its resonant frequency which may be close to the cyclotron frequency, either by an electric field or by a magnetic field. In order to excite the other isotope, a different resonant frequency is required which depends on the plasma density, the relative concentration of electrons if the plasma contains electrons, the strength of the magnetic field, the ratio of charge to mass of the isotope, and possibly on the physical parameters of the plasma apparatus itself, such as the ratio of the length of the plasma column to its radius. The more energetic isotope may be separated by energy dependent chemical reactions, it may be collected by a positively biased probe or else the isotopes may be separated from each other by magnetic fields or in various other ways

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Method of magnetic separation and apparatus therefore  

Science.gov (United States)

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

Oder, Robin R. (Inventor)

1991-01-01

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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

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Magnetic separation of antibiotics by electrochemical magnetic seeding  

International Nuclear Information System (INIS)

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.

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Magnetic separations: From steel plants to biotechnology  

Energy Technology Data Exchange (ETDEWEB)

Magnetic separations have for decades been essential processes in diverse industries ranging from steel production to coal desulfurization. In such settings magnetic fields are used in continuous flow processes as filters to remove magnetic impurities. High gradient magnetic separation (HGMS) has found even broader use in wastewater treatment and food processing. Batch scale magnetic separations are also relevant in industry, particularly biotechnology where fixed magnetic separators are used to purify complex mixtures for protein isolation, cell separation, drug delivery, and biocatalysis. In this review, we introduce the basic concepts behind magnetic separations and summarize a few examples of its large scale application. HGMS systems and batch systems for magnetic separations have been developed largely in parallel by different communities. However, in this work we compare and contrast each approach so that investigators can approach both key areas. Finally, we discuss how new advances in magnetic materials, particularly on the nanoscale, as well as magnetic filter design offer new opportunities for industries that have challenging separation problems.

Cafer T. Yavuz; Arjun Prakash; J.T. Mayo; Vicki L. Colvin [Rice University, Houston, TX (United States). Department of Chemistry

2009-05-15

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Particle acceleration at a reconnecting magnetic separator  

OpenAIRE

While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerator...

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

2014-01-01

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Wide aperture multipole magnets of separator COMBAS  

International Nuclear Information System (INIS)

The high-resolving wide aperture separator COMBAS has been designed and commissioned at the FLNR, JINR. Its magneto-optical structure is based on strong focusing principle. The magnetic fields of analysing magnets M1, M2, M7, M8, contain quadrupole components of alternating sign that provide necessary beam focusing. Besides, all the magnets M1 - M8, contain sextupole and octupole field components, which minimizes the 2nd and 3rd order aberrations. All this allowed one to increase their apertures, to effectively form a beam of the required sizes, and to decrease the channel length. This implementation of wide aperture magnets with combined functions is unique for the separation technology. Three-components magnetic measurements of all the magnets were performed. The measured data allow reconstructing the 3D-distributions of the fields in all the magnets. 3D-maps are supposed to be used for particle trajectory simulations throughout the entire separator

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Microfabricated Passive Magnetic Bead separators  

OpenAIRE

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.

Hansen, Mikkel Fougt; Lund-olesen, Torsten; Smistrup, Kristian; Bruus, Henrik

2006-01-01

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Particle acceleration at a reconnecting magnetic separator  

CERN Document Server

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

Threlfall, J; Parnell, C E; Oskoui, S Eradat

2014-01-01

16

Magnetic separation of uranium from magnesium fluoride  

International Nuclear Information System (INIS)

The attraction or repulsion of particles by a magnetic gradient, based on the respective susceptibilities, provides the basis for physical separation of particles that are comprised predominantly of uranium from those that are predominantly magnesium fluoride (MgF2). To determine the effectiveness of this approach, a bench-scale magnetic separator from the S.G. Frantz Co., Inc. was used. In the Frantz Model L-1, particles are fed through a funnel onto a vibration tray and through a magnetic field. The specific design of the Frantz magnet causes the magnetic field strength to vary along the width of the magnet, setting up a gradient. The tray in the magnetic field is split at a point about half way down its length so that the separated material does not recombine. A schematic is presented of Frantz Model L-1 CN - the same magnet configured for high gradient magnetic separation of liquid-suspended particles. Here different pole pieces create a uniform magnetic field, and stainless steel wood in the canister between the pole pieces creates the high gradient. 1 ref., 6 figs., 2 tabs

17

A ferromagnetic collector for magnetic separation  

International Nuclear Information System (INIS)

A ferromagnetic collector for high gradient magnetic separation formed from steels having a chromium content of at least 17% by weight and a carbon content not exceeding 0.03% by weight. Such steels are resistant to attack by acid and are therefore suitable as magnetic collectors in filters employed in acidic environments. (author)

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A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER  

Energy Technology Data Exchange (ETDEWEB)

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

Salih Ersayin

2005-08-09

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Magnetic separation of uranium from waste materials  

International Nuclear Information System (INIS)

Criteria were developed for selection of candidate wastes for testing magnetic separation of uranium and/or other paramagnetic materials. A survey of Department of Energy (DOE) hazardous wastes was conducted to determine good candidates for bench-scale magnetic separation tests. Representatives of 21 DOE sites were contacted, and materials were identified as potential candidates for magnetic separation. To date, seven samples have been obtained and tested for separability of uranium with a bench-scale magnetic assaying device. The samples tested have been obtained from the K-1401B and K-1401C ponds in Oak Ridge, Tennessee; from waste piles in Maywood, New Jersey; from North and South Ponds in Richland, Washington; and from magnesium fluoride drums in Fernald, Ohio. The magnetic device utilized in these tests can be used in a deflective mode with dry particulate samples or a matrix-gradient mode with either dry particulate or liquid-suspended materials. Uranium separation from magnesium fluoride has shown exceptionally good performance in both wet and dry systems and could be an important application of the technology. 13 figs., 6 tabs

20

Particle acceleration at a reconnecting magnetic separator  

Science.gov (United States)

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

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

2015-02-01

21

Development of magnetic separation system of magnetoliposomes  

Science.gov (United States)

The magnetic separation technology using sub-microsized ferromagnetic particle is indispensable in many areas of medical biosciences. For example, ferromagnetic particles (200-500 nm) are widely used for cell sorting in stem cell research with the use of cell surface-specific antigens. Nanosized ferromagnetic particles (10-20 nm) have been suggested as more suitable in drug delivery studies given their efficiency of tissue penetration, however, the magnetic separation method for them has not been established. One of the major reasons is that magnetic force acting on the object particles decreases drastically as a particle diameter becomes small. In this study, magnetic force acting on the targets was enhanced by the combination of superconducting magnet and the filter consisting of ferromagnetic particle. By doing so, we confirmed that Fe 3O 4 of 20 nm in diameter was trapped in the magnetic filter under an external magnetic field of 0.5 T. Fe 3O 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.; Matuo, Y.; Mishima, F.; Taguchi, T.; Maenosono, S.; Nishijima, S.

2009-10-01

22

Development of magnetic separation system of magnetoliposomes  

International Nuclear Information System (INIS)

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

23

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

24

Magnetic separation from superparamagnetic particle suspensions  

International Nuclear Information System (INIS)

We investigate the magnetophoretic separation of magnetic microparticles from a non-dilute flow in a microfluidic channel and their subsequent field-induced aggregation under the influence of an externally applied magnetic force. This force induces dipolar interactions between the particles that aid in their separation from the flow. Existing analytical models for dilute suspensions cannot be extended to non-dilute suspensions in which interparticle magnetic interactions play an important role. We therefore conduct a parametric investigation of the mechanics of this problem in a microcapillary flow through simulations and experimental visualization. When a magnetic field is applied, the magnetic microparticles form an aggregate on the channel wall that is influenced by the competition between the holding magnetic force and the aggregate-depleting flow shear force. Microparticle collection in the aggregate increases linearly with increasing magnetic field strength and is characterized by distinct buildup and washaway phases. The collected microparticle volume fraction in an aggregate is found to depend on a single dimensional group that depends upon characteristic system parameters.

25

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

26

Particle acceleration at a reconnecting magnetic separator  

Science.gov (United States)

We present first results of test particle orbit calculations in a time-dependent electro-magnetic field configuration which models separator reconnection in three dimensions. The test particle orbits are calculated using the relativistic guiding-centre approximation. The test particles are accelerated to high kinetic energies by the parallel electric field generically associated with three-dimensional magnetic reconnection, with the final energy depending on the choice of model parameters. We will discuss how the test-particle orbits and the energy gain depend on the initial conditions, and how observations (for example, of solar flares) may be used to constrain our model parameters.

Threlfall, James; Neukirch, Thomas; Parnell, Clare; Eradat Oskoui, Solmaz

2014-05-01

27

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

Science.gov (United States)

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

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

2014-01-01

28

A new industrial application of magnetic separation  

International Nuclear Information System (INIS)

The aim of this work was to investigate the application of magnetic separation to the removal and recovery of carbon steel grinding swarf from machining fluids used in large-scale industrial manufacturing processes such as in the automotive industry. Magnetic separation is a technology which has found widespread application in the mineral processing industry and in particular the beneficiation of kaolin clay for use in the paper industry. The technical feasibility of the application was demonstrated in the early stages of the work by the successful treatment of industrial samples using a crude laboratory-scale separator. In addition, the fluid and swarf material underwent extensive analysis using electron microscope-based optical and spectroscopic techniques in order to ascertain the presence of other undesirable components of the fluid that would require removal also. It was demonstrated by these results that the overall objective of the project was the development and testing of a laboratory-scale system which would allow the optimum operational parameters to be ascertained for the design of a commercially viable, large-scale system. A series of detailed trials on large volumes of industrial samples was carried out in conjunction with the development of the modifications that were required to existing magnetic separation theory in order to accommodate the particulars of this application. The trial system was tested to low applied magnetic strengths and high fluid flplied magnetic strengths and high fluid flow velocities in order to optimise the economics of the application, resulting in extraction efficiencies of the order of 99.998% being achieved. During the course of the project, a new type of matrix cleaning system was developed for which a patent was applied and this was successfully tested in the trial system. Economic appraisal of the application suggests that an industrial-scale system could provide reliable, high quality recovery of grinding swarf at a cost of around one cent per cubic metre of fluid. Overall, the results from the project have provided the foundation for the application of magnetic separation to this application. (author)

29

A new industrial application of magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work was to investigate the application of magnetic separation to the removal and recovery of carbon steel grinding swarf from machining fluids used in large-scale industrial manufacturing processes such as in the automotive industry. Magnetic separation is a technology which has found widespread application in the mineral processing industry and in particular the beneficiation of kaolin clay for use in the paper industry. The technical feasibility of the application was demonstrated in the early stages of the work by the successful treatment of industrial samples using a crude laboratory-scale separator. In addition, the fluid and swarf material underwent extensive analysis using electron microscope-based optical and spectroscopic techniques in order to ascertain the presence of other undesirable components of the fluid that would require removal also. It was demonstrated by these results that the overall objective of the project was the development and testing of a laboratory-scale system which would allow the optimum operational parameters to be ascertained for the design of a commercially viable, large-scale system. A series of detailed trials on large volumes of industrial samples was carried out in conjunction with the development of the modifications that were required to existing magnetic separation theory in order to accommodate the particulars of this application. The trial system was tested to low applied magnetic strengths and high fluid flow velocities in order to optimise the economics of the application, resulting in extraction efficiencies of the order of 99.998% being achieved. During the course of the project, a new type of matrix cleaning system was developed for which a patent was applied and this was successfully tested in the trial system. Economic appraisal of the application suggests that an industrial-scale system could provide reliable, high quality recovery of grinding swarf at a cost of around one cent per cubic metre of fluid. Overall, the results from the project have provided the foundation for the application of magnetic separation to this application. (author)

Beharrell, P.A

2000-09-01

30

Fundamental study of phosphor separation by controlling magnetic force  

International Nuclear Information System (INIS)

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

31

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

Science.gov (United States)

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

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

2015-03-01

32

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-01-15

33

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

International Nuclear Information System (INIS)

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

34

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

35

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

36

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

OpenAIRE

A microfabricated magnetic sifter has been designed and fabricated for applications in biological sample preparation. The device enables high-throughput, high-gradient magnetic separation of magnetic nanoparticles by utilizing columnar fluid flow through a dense array (~5000/mm2) of micropatterned slots in a magnetically soft membrane. The potential of the sifter for separation of magnetic nanoparticles conjugated with capture antibodies is demonstrated through quantitative separation experim...

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

2009-01-01

37

Characteristics of magnetic field induction inside a module of a magnetic separator ?????????????? ???????? ???? ? ?????? ?????????? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available Characteristics of magnetic separators are analyzed in the article. Magnetic separators are used to treat various construction materials. Unfortunately, the nature of the magnetic field, generated in their operating zone, is generally not taken into account by their designers. Academic publications fail to provide any detailed basic characteristics of the field induction emitted by magnetic separators in the course of their operation.Magnetic systems of any magnetic separator have a modular structure; they consist of several modules. Single and opposite magnetic elements are usually integrated into one module within a system having permanent magnets. If opposite magnetic elements are used, magnetic field intensity inside the module increases.In this study, characteristics of magnetic induction for single magnetic elements inside various modules of magnetic separators were assessed in a laboratory experiment. Similar characteristics of magnetic induction for single and twin (opposite magnetic elements were compared. In the module consisting of two opposed magnetic elements, the magnetic field becomes stronger compared to the field of a single magnetic element. Magnetic induction in the module recedes as the distance between magnetic elements increases, because of the isolation of the field generated by the opposed magnetic elements.The authors have proven the feasibility and expediency of employment of the superposition principle used to obtain the resulting characteristics. It may be employed to substitute modeling by calculations.???????????????? ???????? ?????????????? ???????? ?????????? ???? ??? ????????? ????????? ? ????????? ??????? ????????? ???????????. ???????????? ?????????????? ???????? ?????????? ???? ??? ????????? ? ????????? ????????? ????????? ??????. ? ??????, ????????? ? ???? ?????????????? ????????? ?????????, ???? ??????????? ?? ????????? ? ????? ?????????? ?????????? ????????, ???? ?? ???? ?????????? ???????????? ?????????? ??????? ???????? ? ?????? ????????? ?? ???? ??? ???????? «??????????» ????????? ?????, ??????????? ??????????????? ?????????? ??????????.???????? ??????????? ? ???????????? ???????????????? ????????????? ???????? ???????????? ??? ???????????? ?????????????? ?????????????? ???????? ???? ????? ??????????????? ?????????? ?????????? ??? ?????? ????????? ????????????? ?????????.

Sandulyak Anna Aleksandrovna

2013-05-01

38

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

Science.gov (United States)

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

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

2015-02-01

39

A High-Throughput SU-8Microfluidic Magnetic Bead Separator  

DEFF Research Database (Denmark)

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

Bu, Minqiang; Christensen, T. B.

2007-01-01

40

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

41

Monodisperse binary nanocomposite in silica with enhanced magnetization for magnetic separation  

OpenAIRE

The majority of research on magnetic nanoparticles has focused on optical, electrical, and magnetic storage areas. Recently, the application of magnetic nanoparticles as magnetically separable nanovehicles for chemical or biological species has become an area of intensive research but with rather different challenging criteria that are yet to be addressed. For example, the enhancement of intrinsically weak magnetic properties, avoidance of magnetic interactions among particles, and improvemen...

Yu, Ch; Lo, Cch; Tam, K.; Tsang, Sc

2007-01-01

42

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

43

Wide aperture multipole magnets of the kinematic separator COMBAS. Basic principles of magnets design  

International Nuclear Information System (INIS)

The high-resolving large aperture kinematic 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 wide aperture magnets M1-M8. Fields of the four magnets, M1, M2, M7, M8, contain quadrupole components of alternating (from magnet to magnet) sign, which provide horizontal and vertical beam focusing. Besides, all the magnets contain higher order field components, namely, sextupole and octupole, which compensate for the 2nd and 3rd order aberrations at the intermediate and final foci. All this allowed one to decrease the total number of magnet elements (and the total channel length), increase their apertures and form effectively the beam of the required longitudinal profile and transverse sizes at both the foci. Such implementation of the large aperture combined functions magnets, having in their field distributions components up to the 3rd order, is unique in the fragment-separation technique. Basic principles of the separator and magnet design, the design and manufacturing steps are presented. Comprehensive magnetic measurements of all the magnets have been done what became the basis of the field quality analysis. Procedures to estimate the magnets field quality and to correct field errors are presented. The measured data allow building 3D-maps of the fields in all the magnets. The 3D-maps are supposed to be used for the particle trajectory simulations throughout the entire separator

44

Low field orientation magnetic separation methods for magnetotactic bacteria  

International Nuclear Information System (INIS)

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

45

Modeling high gradient magnetic separation from biological fluids.  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-01-01

46

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

International Nuclear Information System (INIS)

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

47

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

International Nuclear Information System (INIS)

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

48

On heteroclinic separators of magnetic fields in electrically conducting fluids  

CERN Document Server

In this paper we partly solve the problem of existence of separators of a magnetic field in plasma. We single out in plasma a 3-body with a boundary in which the movement of plasma is of special kind which we call an (a-d)-motion. We prove that if the body is the 3-annulus or the "fat" orientable surface with two holes the magnetic field necessarily have a heteroclinic separator. The statement of the problem and the suggested method for its solution lead to some theoretical problems from Dynamical Systems Theory which are of interest of their own.

Grines, V; Pochinka, O; Zhuzhoma, E

2014-01-01

49

Dendrimer-coated magnetic particles for radionuclide separation  

International Nuclear Information System (INIS)

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

50

On Poor Separation in Magnetically Driven Shock Tube  

DEFF Research Database (Denmark)

Observations made at steady-state running conditions in a magnetically driven shock tube, with parallel-plate electrodes, showed that for a given discharge voltage, sufficient separation between the shock and the current-sheet occurred only at relatively high discharge pressures. As a comparison, poor separations were also noted in conventional diaphragm-type shock tubes running at low initial pressures. It is demonstrated that the observed poor separation can be explained by a mass leakage, instead of through the wall boundary layer, but through the current-sheet itself.

Chang, C.T.

1973-01-01

51

Rapid and continuous magnetic separation in droplet microfluidic devices.  

Science.gov (United States)

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

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

2015-01-22

52

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 benace and the later part could be recycling to sintering process for alumina production or used as construction material.

53

Pair separation of magnetic elements in the quiet Sun  

CERN Document Server

The dynamic properties of the quiet Sun photosphere can be investigated by analyzing the pair dispersion of small-scale magnetic fields (i.e., magnetic elements). By using $25$ hr-long Hinode magnetograms at high spatial resolution ($0".3$), we tracked $68,490$ magnetic element pairs within a supergranular cell near the disk center. The computed pair separation spectrum, calculated on the whole set of particle pairs independently of their initial separation, points out what is known as a super-diffusive regime with spectral index $\\gamma=1.55\\pm0.05$, in agreement with the most recent literature, but extended to unprecedented spatial and temporal scales (from granular to supergranular). Furthermore, for the first time, we investigated here the spectrum of the mean square displacement of pairs of magnetic elements, depending on their initial separation $r_0$. We found that there is a typical initial distance above (below) which the pair separation is faster (slower) than the average. A possible physical interp...

Giannattasio, F; Biferale, L; Del Moro, D; Sbragaglia, M; Rubio, L Bellot; Gosic, M; Suarez, D Orozco

2014-01-01

54

Magnetic Separations with Magnetite: Theory, Operation, and Limitations  

International Nuclear Information System (INIS)

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

55

Maximizing the recovery of fine iron ore using magnetic separation  

Scientific Electronic Library Online (English)

Full Text Available 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.

2012-03-01

56

Magnetic nano-sorbents for fast separation of radioactive waste  

International Nuclear Information System (INIS)

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

57

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation  

International Nuclear Information System (INIS)

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 ?m with 4 wt.% over 100 ?m and content metallic iron of 93 wt%. (author)

58

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

Science.gov (United States)

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

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

2010-08-01

59

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

60

Design of Power Magnetic Chute Separator and Minimization of its External Magnetic Field.  

Czech Academy of Sciences Publication Activity Database

St. Petersburg : St. Petersburg Polytechnical University, 2005, s. 1-4. ISBN 5-93208-034-0. [International Conference on 2005 IEEE St. Petersburg PowerTech [0046062]. St. Petersburg (RU), 27.06.2005-30.06.2005] Institutional research plan: CEZ:AV0Z20570509 Keywords : magnetic separator * magnetic field * numerical analysis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

Karban, P.; Ulrych, B.; Doležel, Ivo

61

Rapid cycling synchrotron magnet with separate ac and dc circuit  

International Nuclear Information System (INIS)

In present rapid cycling synchrotron magnets ac and dc currents flow in the same coil to give the desired field. The circuit reactance is made zero at dc and the operating frequency by running the magnet in series with an external parallel resonant LC current. We propose to return the ac flux in a gap next to the synchrotron. The dc coil encloses the ac magnetic circuit and thus links no ac flux. A shorted turn between the dc coil and ac flux enhances the separation of the two circuits. Several interesting developments are possible. The dc coil could be a stable superconductor to save power. The ac flux return gap could be identical with the synchrotron gap and contain a second synchrotron. This would double the output of the system. If the return flux gap were used for a booster, the ac coil power could be greatly reduced or radiation hardening of the ac coil could be simplified

62

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

Science.gov (United States)

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

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

2015-03-24

63

Magnetically separable titania-coated nickel ferrite photocatalyst  

Energy Technology Data Exchange (ETDEWEB)

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

Chung, Yun Seup; Park, Seung Bin; Kang, Duk-Won

2004-08-15

64

Magnetically separable titania-coated nickel ferrite photocatalyst  

International Nuclear Information System (INIS)

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

65

Possibilities of power coal desulphurization from upper nitra basin by means of magnetic separation  

Directory of Open Access Journals (Sweden)

Full Text Available The paper deals with the application of magnetic separation in coal desulphurization. Specimens of power coal from Upper Nitra basin were subjected to breaking, grinding and wet high gradient magnetic separation under magnetic field induction of 1,7 T. Sulphidic sulphur contents and recoveries into separation products have been observed.

Lovás Michal

1997-09-01

66

Removal System of Arsenic from Geothermal Water by Magnetic Separation Technology with a Superconducting Magnet  

Science.gov (United States)

We have developed an arsenic removal system from geothermal water by High Gradient Magnetic Separation (HGMS), thus using a superconducting magnet to supply hot water for public use. We reduced arsenic to approximately 0.02mg/L (less than the effluence standard of 0.1mg/L and slightly larger than the environmental standard of 0.01mg/L in Japan) by using an experimental plant, and we investigated the optimum HGMS system using a superconducting magnet. The plant consists of a pretreatment system that adds extra magnetization to arsenic by chemical reaction, and a HGMS device that uses a superconducting magnet that extracts magnetized arsenic from geothermal water. In this paper we present the experimental results.

Okada, H.; Mitsuhashi, K.; Ohara, T.; Wada, H.; Kudoh, Y.; Nakazawa, H.; Chiba, A.

2005-07-01

67

Plasma separation process: Magnet move to Oak Ridge National Laboratory  

International Nuclear Information System (INIS)

This is the final report on the series of operations which culminated with the delivery of the Plasma Separation Process prototype magnet system (PMS) to Building K1432 at Oak Ridge National Laboratory (ORNL). This procedure included real time monitoring of the cold mass support strut strain gauges and an in-cab rider to monitor the instrumentation and direct the driver. The primary technical consideration for these precautions was the possibility of low frequency resonant vibration of the cold mass when excited by symmetrical rough road conditions at specific speeds causing excess stress levels in the support struts and consequent strut failure. A secondary consideration was the possibility of high acceleration loads due to sudden stops, severe road conditions, of impacts. The procedure for moving and transportation to ORNL included requirements for real time continuous monitoring of the eight strut stain gauges and three external accelerometers. Because the strain gauges had not been used since the original magnet cooldown, it was planned to verify their integrity during magnet warmup. The measurements made from the strut strain gauges resulted in stress values that were physically impossible. It was concluded that further evaluation was necessary to verify the usefulness of these gauges and whether they might be faulty. This was accomplished during the removal of the magnet from the building. 6 figs., 1 tab

68

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

69

Development of a mobile-type magnetic separator using high-Tc bulk superconductors  

International Nuclear Information System (INIS)

The authors have devised an advanced, mobile-type water treatment system consisting of a membrane separator and a magnetic separator, which uses long high-Tc bulk superconductors (SCs), to quickly remove phytoplankton multiplying in highly eutrophic lakes and dams. The prototype magnetic separator system was designed and fabricated. The fabricated system consists of three components; a pre-process unit, a rotating membrane separator and a magnetic separator. The capacity of the magnetic separator is 100 t/day. The water cleaning test using kaolin was conducted, displaying water cleaning power of 90% or higher. Further, most chlorophyll A and phosphorus were successfully removed in another test

70

Primary beneficiation of tantalite using magnetic separation and acid leaching  

Science.gov (United States)

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

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

2014-12-01

71

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

Science.gov (United States)

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

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

2015-02-01

72

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.

73

Study on a mobile-type magnetic separator applying high-Tc bulk superconductors  

International Nuclear Information System (INIS)

We have developed a new water-treatment system that consists of a membrane separator and a magnetic separator that uses long high-Tc bulk superconductors (SCs) as permanent magnets. Basic tests were performed using a new prototype water-treatment system to verify the separator's ability to remove water bloom. Based on the test results, we design the mobile-type magnetic separator system. The designed magnetic separator system consists of three components; a pre-process unit, a rotating membrane separator and a magnetic separator. The capacity of the magnetic separator is 100 ton/day. Removal rate is 90% or more. It is thought that the system is compact and high efficiency

74

Magnetic and fluorescence-encoded polystyrene microparticles for cell separation  

Science.gov (United States)

Materials assisting with the efforts of cell isolation are attractive for numerous biomedical applications including tissue engineering and cell therapy. Here, we have developed surface modification methods on microparticles for the purposes of advanced cell separation. Iron oxide nanoparticles were incorporated into 200 ?m polystyrene microparticles for separation of particle-bound cells from non-bound cells in suspension by means of a permanent magnet. The polystyrene microparticles were further encoded with fluorescent quantum dots (QD) as identification tags to distinguish between specific microparticles in a mixture. Cluster of differentiation (CD) antibodies were displayed on the surface of the microparticles through direct adsorption and various methods of covalent attachment. In addition, a protein A coating was used to orientate the antibodies on the microparticle surface and to maximise accessibility of the antigen-binding sites. Microparticles which carried CD antibodies via covalent attachment showed greater cell attachment over those modifications that were only adsorbed to the surface through weak electrostatic interactions. Greatest extent of cell attachment was observed on microparticles modified with protein A - CD antibody conjugates. B and T lymphocytes were successfully isolated from a mixed population using two types of microparticles displaying B and T cell specific CD antibodies, respectively. Our approach will find application in preparative cell separation from tissue isolates and for microcarrier-based cell expansion.

Bradbury, Diana; Anglin, Emily J.; Bailey, Sheree; Macardle, Peter J.; Fenech, Michael; Thissen, Helmut; Voelcker, Nicolas H.

2008-12-01

75

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

Science.gov (United States)

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

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

2014-09-01

76

Demonstration of magnetically activated and guided isotope separation  

Science.gov (United States)

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

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

2014-08-01

77

Magnetic separation - Advanced nanotechnology for future nuclear fuel recycle  

International Nuclear Information System (INIS)

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

78

Trapped field enhancement of five-aligned superconducting bulk magnetized by pulse field for magnetic separation  

International Nuclear Information System (INIS)

Five-aligned superconducting bulk magnet system has been improved and the trapped field characteristics have been investigated by the pulse field magnetization (PFM). The trapped field BT(z = 0 mm) is enhanced to 2.7 T at the bulk surface because of the lowering temperature Ts and the enhancement of the applied field Bex, compared with those for the proto-type system [Physica C 445-448 (2006) 399]. The operating fields, BT(2 mm) at the vacuum sheath surface and BT(9 mm) at the surface of the rotating membrane in water-treatment system, are also enhanced because of some structural improvement, and the multi-bulk magnet system available for the magnetic separation is realized

79

Titania deposited on soft magnetic activated carbon as a magnetically separable photocatalyst with enhanced activity  

International Nuclear Information System (INIS)

Magnetically separable composite photocatalysts, TiO2 deposited on soft magnetic ferrite activated carbon (TFAC), were prepared by sol-gel and dip-coating technique. The prepared composites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectra (FTIR), optical absorption spectroscopy, vibrating sample magnetometer (VSM) and nitrogen adsorption. These photocatalysts exhibited enhanced photocatalytic activity compared to Degussa P25 for the degradation of methyl orange (MO) in aqueous solution. The kinetics of MO degradation was well fitted to the Langmuir-Hinshelwood model. The samples showed good magnetic response and could be completely recovered by an external magnet. Furthermore, the photocatalysts could maintain high photocatalytic activity after five cycles, and the degradation rate of MO was still close to 90%.

80

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

Science.gov (United States)

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

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

2015-03-01

81

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.

82

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

Energy Technology Data Exchange (ETDEWEB)

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.

Okamoto, T., E-mail: okamoto-takayuki@ed.tmu.ac.jp [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Tachibana, S.; Miura, O. [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Takeuchi, M. [Komazawa Jin Clinic, 1-19-8 Komazawa, Setagayaku, Tokyo 154-0012 (Japan)

2011-11-15

83

Magnetic separation technique for groundwater by five HTS melt-processed bulk magnets arranged in a line  

International Nuclear Information System (INIS)

A magnetic separation was practically conducted by 10-pole HTS bulk magnets. The HTS bulk magnets were activated to 2.5 T by feeding pulsed fields of 6 T. The separation ratio of actual groundwater exceeded 70% at less than 4.8 l/min. The flocks without magnetite powder were obviously attracted to the magnetic poles. A magnetic separation study for groundwater purification has been practically conducted by using the multi-pole magnet system. The magnetic pole was composed of 10 open magnetic spaces by arranging five HTS melt-processed bulk magnets in a line in a vacuum sheath. The individual bulk magnets were activated by feeding intense pulsed magnetic fields up to 6 T. The magnetic field distribution was estimated with respect to various pole arrangements. The actual groundwater samples of Sanjo City were processed so as to form large precipitates by adding the coagulant and pH controlling. The maximum separation ratio of the iron-bearing precipitates has exceeded over 70% when slurry water was exposed to 10 magnetic poles of up to 2.5 T at a flowing rate of less than 4.8 l/min. An obvious attraction of flocks to the magnetic poles was observed even when the water contains no magnetite powder at the flow rate of 1.01 l/min. This implies the validity of the multi-pole magnet system with respect to the actual application to water purification.

84

Influences of separate position to radial direction between bulk superconductor and permanent magnetic ring about magnetic levitation and rotating characteristics  

International Nuclear Information System (INIS)

The segmental structure of bulk superconductor will be needed designing ultra-large scale high temperature superconducting magnetic bearing for MWh class superconducting flywheel. The N-S poles of permanent magnetic ring assembly were arranged alternately to radial direction and the influences to magnetic levitation and rotating characteristics of the separate position of bulk superconductor to radial direction were tested. It was found when the separate position of bulk superconductor was coincided with the joint of the N-S poles of permanent magnets, both the magnetic levitation and the rotating characteristics were the same as the case of non-separate superconductor. When its position was the center of one side pole of permanent magnets, the levitation was the same as the case of non-separate superconductor, but the behavior of rotating characteristics changed and the loss increased as compared with the case of non-separate type

85

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

Science.gov (United States)

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

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

2010-12-01

86

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

Science.gov (United States)

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

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

1980-11-06

87

Magnetic separation techniques in sample preparation for biological analysis: a review.  

Science.gov (United States)

Sample preparation is a fundamental and essential step in almost all the analytical procedures, especially for the analysis of complex samples like biological and environmental samples. In past decades, with advantages of superparamagnetic property, good biocompatibility and high binding capacity, functionalized magnetic materials have been widely applied in various processes of sample preparation for biological analysis. In this paper, the recent advancements of magnetic separation techniques based on magnetic materials in the field of sample preparation for biological analysis were reviewed. The strategy of magnetic separation techniques was summarized. The synthesis, stabilization and bio-functionalization of magnetic nanoparticles were reviewed in detail. Characterization of magnetic materials was also summarized. Moreover, the applications of magnetic separation techniques for the enrichment of protein, nucleic acid, cell, bioactive compound and immobilization of enzyme were described. Finally, the existed problems and possible trends of magnetic separation techniques for biological analysis in the future were proposed. PMID:24809747

He, Jincan; Huang, Meiying; Wang, Dongmei; Zhang, Zhuomin; Li, Gongke

2014-12-01

88

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

International Nuclear Information System (INIS)

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. - Highlights: • We develop a simple diamagnetic particle and cell separation technique in ferrofluids. • Two offset magnets are used to achieve a sheath-free continuous separation in a straight microchannel. • The technique is demonstrated through the magnetic separation of polystyrene particles and yeast cells. • The effects of ferrofluid speed and magnet-channel distance are examined on particle separation. • The predictions from an analytical model agree with the experimental data quantitatively

89

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

Energy Technology Data Exchange (ETDEWEB)

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. - Highlights: • We develop a simple diamagnetic particle and cell separation technique in ferrofluids. • Two offset magnets are used to achieve a sheath-free continuous separation in a straight microchannel. • The technique is demonstrated through the magnetic separation of polystyrene particles and yeast cells. • The effects of ferrofluid speed and magnet-channel distance are examined on particle separation. • The predictions from an analytical model agree with the experimental data quantitatively.

Zeng, Jian; Deng, Yanxiang [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States); Vedantam, Pallavi; Tzeng, Tzuen-Rong [Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314 (United States); Xuan, Xiangchun, E-mail: xcxuan@clemson.edu [Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921 (United States)

2013-11-15

90

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

Science.gov (United States)

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

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

2006-05-01

91

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

92

Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction  

International Nuclear Information System (INIS)

The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

93

Magnetic separation as a method to assist mineralogical characterization of rocks by X-ray diffraction  

Energy Technology Data Exchange (ETDEWEB)

The X-ray diffraction (XRD) corresponds to one of the main techniques for characterization of structures in crystalline materials widely used in the identification of minerals in samples of geological materials such as rocks. However, the large number of mineral phases present in a rock sample can generate excess peaks in the diffractogram, and it can promote overlapping peaks and induce erroneous identification. The purpose of this study was to perform magnetic separation of minerals from rock samples in order to enable the identification of the minerals by XRD. For this magnetic separation, two samples of rock were selected: a sample of high silica content and a sample with low silica content. The magnetic separation of minerals from each sample was performed using the magnetic separator isodynamic Frantz. Posteriorly, the fractions obtained in magnetic separations were analyzed by XRD. In the sample with high silica content, it was obtained a fraction where was identified the accessory mineral epidote, which had not been identified in the total sample diffractogram. In the sample with low silica content, the magnetic separation into several mineral fractions made possible to obtain diffraction patterns with fewer peaks and peaks with higher relative intensities, which allowed its mineralogical characterization. The results showed that the mineral separation by the magnetic separator Frantz made the identification of accessory minerals by XRD and the characterization of samples which have many mineral phases possible, which proves that magnetic separation by Frantz is a method which can assist analyses by XRD. (author)

Silva, Amanda Luzia da; Oliveira, Arno Heeren de; Fernandes, Maria Lourdes Souza, E-mail: amanda@igc.ufmg.br, E-mail: heeren@nuclear.ufmg.br, E-mail: amanda@igc.ufmg.br, E-mail: lurdesfernandes@ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horionte, MG (Brazil)

2013-07-01

94

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

Energy Technology Data Exchange (ETDEWEB)

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

Qiang, You; Paszczynski, Andrzej; Rao, Linfeng

2011-10-30

95

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

DEFF Research Database (Denmark)

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. (c) 2005 Elsevier B.V. All rights reserved.

Smistrup, Kristian; Hansen, Ole

2005-01-01

96

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

97

Coupled particle-fluid transport and magnetic separation in microfluidic systems with passive magnetic functionality  

Science.gov (United States)

A study is presented of coupled particle-fluid transport and field-directed particle capture in microfluidic systems with passive magnetic functionality. These systems consist of a microfluidic flow cell on a substrate that contains embedded magnetic elements. Two systems are considered that utilize soft- and hard-magnetic elements, respectively. In the former, an external field is applied to magnetize the elements, and in the latter, they are permanently magnetized. The field produced by the magnetized elements permeates into the flow cell giving rise to an attractive force on magnetic particles that flow through it. The systems are studied using a novel numerical/closed-form modelling approach that combines numerical transport analysis with closed-form field analysis. Particle-fluid transport is computed using computational fluid dynamics (CFD), while the magnetic force that governs particle capture is obtained in closed form. The CFD analysis takes into account dominant particle forces and two-way momentum transfer between the particles and the fluid. The two-way particle-fluid coupling capability is an important feature of the model that distinguishes it from more commonly used and simplified one-way coupling analysis. The model is used to quantify the impact of two-way particle-fluid coupling on both the capture efficiency and the flow pattern in the systems considered. Many effects such as particle-induced flow-enhanced capture efficiency and flow circulation are studied that cannot be predicted using one-way coupling analysis. In addition, dilute particle dispersions are shown to exhibit significant localized particle-fluid coupling near the capture regions, which contradicts the commonly held view that two-way coupling can be ignored when analysing high-gradient magnetic separation involving such particle systems. Overall, the model demonstrates that two-way coupling needs to be taken into account for rigorous predictions of capture efficiency, especially for applications involving high particle loading and/or low flow rates. It is computationally more efficient and accurate than purely numerical models and should prove useful for the rational design and optimization of novel magnetophoretic microsystems.

Khashan, Saud A.; Furlani, Edward P.

2013-03-01

98

Open gradient magnetic separation utilizing NbTi, Nb3Sn and Bi-2223 materials  

International Nuclear Information System (INIS)

Superconducting magnets enable the magnetic separation of particles with small magnetic susceptibility. In this paper, we compare superconducting separator magnets made of Nb3Sn, NbTi and Bi-2223 materials. The separator system is used to determine the optimal conditions for separation of various slurries. The magnet should provide a high and nearly constant magnetic force density. These requirements are met with racetrack coils. Geometries consisting of one or two racetracks have been examined. In order to keep the material costs at a reasonable level, the volume of the magnet has been minimized taking into account the constraints set by the force and current densities. Sequential quadratic programming (SQP) was used in the optimization procedure. The force density has been calculated using an analytical two-dimensional model. The critical current density of the coil was obtained by solving the magnetic flux density from a three-dimensional model using the finite element method. We have compared magnetic force densities and wire lengths in magnets made of different materials. For magnets made of low-temperature superconductors, the optimized geometry consisted of two coils. For magnets made of high-temperature superconductors, the minimum volume was achieved by using only one coil. (author)

99

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

100

Proposal for implanting a magnetic stable isotope separator  

International Nuclear Information System (INIS)

The implantation of an electromagnetic isotope separator able to separate elements of mass from 20 to 250 a.m.u., with an enrichment factor from 10 to 200 times the initial concentration, depending on the elements, is proposed. The most suitable separator type for Brazilian CNEN, considering building installations and minimum conditions for the equipment facilities, the retinue chronogram, the infrastructure, and the personnel training for operation is defined. (M.C.K.)

101

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.

102

Electronic stabilization of the Si(111)5 × 2-Au surface: Pb and Si adatoms  

International Nuclear Information System (INIS)

Using scanning tunneling microscopy/spectroscopy (STM/STS), angle resolved photoemission spectroscopy (ARPES) and first-principles density functional theory (DFT), we study the structural and the electronic properties of the Si(111)5 × 2-Au surface decorated with Pb adatoms. The STM topography data reveal that Pb adatoms form a similar superstructure to that observed in the case of Si adatoms on a bare Si(111)5 × 2-Au surface. The DFT calculations show that preferential adsorption sites of Pb atoms are located near the double Au chain. Bias dependent STM topography and spectroscopy together with the DFT calculations allow us to distinguish Pb from Si adatoms. Both the Si and Pb adatoms modify the electronic properties in the same way, which confirms the electronic origin of the stabilization of the surface. (paper)

103

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

International Nuclear Information System (INIS)

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

104

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

Science.gov (United States)

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

Chen, Haitao; Kaminski, Michael D.; Ebner, Armin D.; Ritter, James A.; Rosengart, Axel J.

2007-06-01

105

Colossal magnetoresistance and phase separation in magnetic semiconductors  

CERN Document Server

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

Nagaev, Eduard L

2002-01-01

106

Electric Charge Separation in Strong Transient Magnetic Fields  

OpenAIRE

We discuss various mechanisms for the creation of an asymmetric charge fluctuation with respect to the reaction plane among hadrons emitted in relativistic heavy-ion collisions. We show that such mechanisms exist in both, the hadronic gas and the partonic phases of QCD. The mechanisms considered here all require the presence of a strong magnetic field (the ``chiral magnetic effect''), but they do not involve parity or charge-parity violations. We analyze how a transient loca...

Asakawa, Masayuki; Majumder, Abhijit; Mu?ller, Berndt

2010-01-01

107

Effect of anisotropy in temperature dynamics of magnetic phase separation in europium hexaboride  

Energy Technology Data Exchange (ETDEWEB)

The ESR measurements of the EuB{sub 6} single crystal samples were executed on frequency 9.25 GHz in TE{sub 102} rectangular cavity in the temperature range from 15 to 300 K. We used samples of identical form and size, but different crystallografic orientation to estimate their magnetization. At T = 30 - 40 K was observed the magnetic phase separation, which, most likely, is accompanied also by charging separation. The anisotropy magnetization of more intensive magnetic phase (with anti-Kondo interaction) along the different crystallographic directions was found above a temperature of the ferromagnetic transition. We conclude that this result connect with existence the ferronic states and charging separation in the EuB{sub 6} single crystal. Estimations of angular distribution of the magnetic moment of ferrons in EuB{sub 6} are made.

Altshuler, T S; Goryunov, Yu V [Zavoiskii Physical-Technical Institute, Russian Academy of Sciences, Sibirskii trakt 10/7, Kazan 29, 420029 (Russian Federation); Shitsevalova, N Yu; Dukhnenko, A, E-mail: gorjunov@kfti.knc.r [Frantsevich Institute of Materials Science Problems, National Academy of Sciences of Ukraine ul. Krzhizhanovskogo 3, Kiev, 03680 (Ukraine)

2010-01-01

108

Detection of carcinoembryonic antigen using functional magnetic and fluorescent nanoparticles in magnetic separators  

International Nuclear Information System (INIS)

We combined a sandwich immunoassay, anti-CEA/CEA/anti-CEA, with functional magnetic (?80 nm) and fluorescent (?180 nm) nanoparticles in magnetic separators to demonstrate a detection method for carcinoembryonic antigen (CEA). Determination of CEA in serum can be used in clinical diagnosis and monitoring of tumor-related diseases. The CEA concentrations in samples were deduced and determined based on the reference plot using the measured fluorescent intensity of sandwich nanoparticles from the sample. The linear range of CEA detection was from 18 ng/mL to 1.8 pg/mL. The detection limit of CEA was 1.8 pg/mL. In comparison with most other detection methods, this method had advantages of lower detection limit and wider linear range. The recovery was higher than 94%. The CEA concentrations of two serum samples were determined to be 9.0 and 55 ng/mL, which differed by 6.7% (9.6 ng/mL) and 9.1% (50 ng/mL) from the measurements of enzyme-linked immunosorbent assay (ELISA), respectively. The analysis time can be reduced to one third of ELISA. This method has good potential for other biomarker detections and biochemical applications.

109

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

Science.gov (United States)

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

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

2014-05-01

110

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.;

111

Fluctuations of the Solitary Bubble at the Separation from the Air Cavity, Compressed by the Magnetic Field in Magnetic Liquid  

Directory of Open Access Journals (Sweden)

Full Text Available In the article, on the basis of the concept of "display" of geometry of a free surface of the "low-magnetic" environment by the topography of isolines of the module of intensity of a magnetic field, it is studied a form of a free surface of magnetic fluid in a static condition at the initial stage of rapprochement of a ring magnet with a surface of a column of magnetic fluid in a tube and at a stage of pressing of a cavity to a bottom. It is shown that the separation of bubbles from an air cavity occurs in close proximity to the plane of symmetry of a ring magnet on its axis. It is described the method and experimental installation for studying the possibility of electromagnetic indication of sizes of the air bubbles, being in magnetic fluid. It is discussed the results of experimental research on process of a separation of solitary air bubble from a cavity, contained in magnetic fluid and squeezed by ponderomotive forces of a magnetic field which are of interest for creation of essentially new technique of the dosed supply of small amount of gas in the reactor.

M.L. Boev

2013-12-01

112

Separation of Uranium by an Extractant Encapsulated Magnetic Alginate Gels  

Science.gov (United States)

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

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

113

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.

2007-05-01

114

Structure and energetics of Si(111)-(5x2)-Au  

OpenAIRE

We propose a new structural model for the Si(111)-(5x2)-Au reconstruction. The model incorporates a new experimental value of 0.6 monolayer for the coverage of gold atoms, equivalent to six gold atoms per 5x2 cell. Five main theoretical results, obtained from first-principles total-energy calculations, support the model. (1) In the presence of silicon adatoms the periodicity of the gold rows spontaneously doubles, in agreement with experiment. (2) The dependence of the surfa...

Erwin, Steven C.; Barke, Ingo; Himpsel, F. J.

2009-01-01

115

Magnetic field effect on separation processes in a beam-plasma discharge in crossed electric and magnetic fields  

International Nuclear Information System (INIS)

The effect of magnetic field on processes of isotope separation in beam-plasma discharge in crossed fields is experimentally investigated. Parameters of an electron beam remained unchanged: Usub(p)=3.5 kV, Isub(p)=1.6 A. Working gas is neon with natural isotope ratio n0=1.5x1013 cm-3. Radial voltage 20 V, the magnetic field strength in the centre varied from 2 to 4.5 kGs. Volumetric beam-plasma discharge arises under these conditions in a working chamber. It is clarified that decrease of the magnetic field improves conditions of holding volumetric beam-plasma discharge as well as it results in increase of radial current. In this case energy consumption for separation decrease by more than an order, increase of separation factor ? takes place, the value ?=1.4 is attained for natural mixture of neon isotopes

116

Interaction of separated ferromagnetic domains in a hole-doped manganite achieved by a magnetic field  

International Nuclear Information System (INIS)

We report the change in the magnetic microstructure with the application of a magnetic field to a hole-doped manganite La0.81Sr0.19MnO3 in the mixed-phase state, in which ferromagnetic and paramagnetic phases coexist. In situ observations by electron holography have revealed that the applied magnetic field generates a ''channel'' of the magnetic flux in the paramagnetic phase region, thereby connecting the separated ferromagnetic domains. The magnetic flux density of this channel is estimated at 0.33 T, which is comparable with that of the ferromagnetic domains. The connection of the separated ferromagnetic domains appears to promote the conduction in the mixed-phase state as predicted for many manganites exhibiting the magnetoresistance effect

117

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

118

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)

119

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

120

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

121

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

Science.gov (United States)

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

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

2009-09-01

122

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

Science.gov (United States)

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

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

2014-10-01

123

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

International Nuclear Information System (INIS)

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

124

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

125

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

126

Experiments with a magnetic separator for heavy recoil ions  

International Nuclear Information System (INIS)

Using a triple-focusing (position and momentum), crescent-shaped separator for heavy recoil-ions different experiments were performed. The improvement consists in the enhancement of the transmission from 8% to 25% for 500 keV recoil ions from the reaction 238U(?, 3n)sup(239m)Pu. For sup(237m)Pu the electromagnetic decay of the 1.1 ?s shape isomer into the 82 ns shape isomer was searched for. The upper limit for gamma decay is 1.25 +- 1.25% for Esub(?) = 200 keV and for electron decay 0.29 +- 0.29% in comparison to isomeric fission. The upper limit for interband transitions is 2.5% (2 delta), from which the upper limit of the partial half-life for the electromagnetic decay of the 1.1 ?s isomer is calculated to 44 ?s. Due to the performed interpretation the spin difference between both isomers extends at least to ?I = 3. For sup(238m)U the back-decay into the 1. minimum by the EO-transition and the converted 2+ ? 0+ transition in the first decay and the decay by alpha articles was looked for both in single measurements as in a coincidence measurement to L-X-ray quanta. The upper limits are GAMMAsub(EO) = 2.0, GAMMAsub(?)/GAMMAsub(F) = 0.4 and GAMMA(back-decay)/GAMMAsub(F) approx. equal to 100. (orig./HSI)

127

Particle Capture Efficiency in a Multi-Wire Model for High Gradient Magnetic Separation  

CERN Document Server

High gradient magnetic separation (HGMS) is an efficient way to remove magnetic and paramagnetic particles, such as heavy metals, from waste water. As the suspension flows through a magnetized filter mesh, high magnetic gradients around the wires attract and capture the particles, removing them from the fluid. We model such a system by considering the motion of a paramagnetic tracer particle through a periodic array of magnetized cylinders. We show that there is a critical Mason number (ratio of viscous to magnetic forces) below which the particle is captured irrespective of its initial position in the array. Above this threshold, particle capture is only partially successful and depends on the particle's entry position. We determine the relationship between the critical Mason number and the system geometry using numerical and asymptotic calculations. If a capture efficiency below 100% is sufficient, our results demonstrate how operating the HGMS system above the critical Mason number but with multiple separa...

Eisenträger, Almut; Griffiths, Ian M

2014-01-01

128

Magnetic nanoparticle-based separation of metallic and semiconducting carbon nanotubes  

International Nuclear Information System (INIS)

We report a simple and scalable method for the separation of semiconducting single-walled carbon nanotubes (SWNTs) from metallic SWNTs using magnetic nanoparticles (MNPs) functionalized with polycationic tri-aminated polysorbate 80 (TP80). MNPs-TP80 are selectively adsorbed on acid-treated semiconducting SWNTs, which makes the semiconducting SWNTs be highly concentrated to over 95% under a magnetic field. Almost all the field effect transistor network devices, which were fabricated using separated semiconducting SWNTs, exhibited a p-type semiconducting behavior with an on/off ratio of higher than 104.

129

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

Science.gov (United States)

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

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

2015-05-01

130

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

Science.gov (United States)

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

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

2013-11-21

131

Separation of Variables in the Classical Integrable SL(3) Magnetic Chain  

OpenAIRE

There are two fundamental problems studied by the theory of hamiltonian integrable systems: integration of equations of motion, and construction of action-angle variables. The third problem, however, should be added to the list: separation of variables. Though much simpler than two others, it has important relations to the quantum integrability. Separation of variables is constructed for the $SL(3)$ magnetic chain --- an example of integrable model associated to a nonhyperel...

Sklyanin, E. K.

1992-01-01

132

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

OpenAIRE

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

133

Rapid detection and purification of sequence specific DNA binding proteins using magnetic separation  

OpenAIRE

In this paper, a method for the rapid identification and purification of sequence specific DNA binding proteins based on magnetic separation is presented. This method was applied to confirm the binding of the human recombinant USF1 protein to its putative binding site (E-box) within the human SOX3 protomer. It has been shown that biotinylated DNA attached to streptavidin magnetic particles specifically binds the USF1 protein in the presence of competitor DNA. It has also been demonstrated tha...

TIJANA SAVIC; DANIJELA DRAKULIC; ALEKSANDAR KRSTIC; ISIDORA PETROVIC; JELENA DJUROVIC; MARIJA MOJSIN; MILENA STEVANOVIC

2006-01-01

134

High gradient magnetic particle separation in viscous flows by 3D BEM  

Science.gov (United States)

The boundary element method was applied to study the motion of magnetic particles in fluid flow under the action of external nonuniform magnetic field. The derived formulation combines the velocity-vorticity resolved Navier-Stokes equations with the Lagrange based particle tracking model, where the one-way coupling with fluid phase was considered. The derived algorithm was used to test a possible design of high gradient magnetic separation in a narrow channel by computing particles trajectories in channel flow under the influence of hydrodynamic and magnetic forces. Magnetic field gradient was obtained by magnetization wires placed outside of the channel. Simulations with varying external magnetic field and flow rate were preformed in order to asses the collection efficiency of the proposed device. We found that the collection efficiency decreases linearly with increasing flow rate. Also, the collection efficiency was found to increase with magnetic field strength only up a saturation point. Furthermore, we found that high collection efficiently is not feasible at high flow velocity and/or at weak magnetic field. Recommendation for optimal choice of external magnetic field and flow rate is discussed.

Ravnik, J.; Hriberšek, M.

2013-04-01

135

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

Energy Technology Data Exchange (ETDEWEB)

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

Zhang, Yali; Li, Huaimei [College of Chemical Engineering, Shandong University of Technology, 255081, Zibo, Shandong (China); Yu, Xianjin, E-mail: xjy@sdut.edu.cn [College of Chemical Engineering, Shandong University of Technology, 255081, Zibo, Shandong (China)

2012-04-30

136

Laboratory test of an industrial superconducting magnetic separator for kaolin clay purification  

Science.gov (United States)

An industrial magnetic separator with 0.5 m warm bore, 1 m effective length, 3.5 T central field superconducting magnet system, a high gradient reciprocating canister and corresponding slurry and control systems for kaolin clay purification has been constructed. Laboratory tests at different magnetic fields (1-3.5 T) and slurry velocities (0.5-3cm/s) have been conducted. The results show the stable operation and the productivity of 3 t/h dry clay powder with 3.5-5 points brightness enhancement.

Yan, L. G.; Song, S. S.; Yi, C. L.; Ye, Z. X.; Nan, H. L.; Dai, Y. M.; Zhang, F. Y.; Li, H. D.; Ye, P.; Tu, G. B.

1994-07-01

137

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

138

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 (Cs 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.

139

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

International Nuclear Information System (INIS)

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

140

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

Science.gov (United States)

Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting-water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism. PMID:22333161

Zhang, Yali; Li, Huaimei; Yu, Xianjin

2012-04-30

141

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-01-29

142

Separation and enrichment of enantiopure from racemic compounds using magnetic levitation.  

Science.gov (United States)

Crystallization of a solution with high enantiomeric excess can generate a mixture of crystals of the desired enantiomer and the racemic compound. Using a mixture of S-/RS-ibuprofen crystals as a model, we demonstrated that magnetic levitation (MagLev) is a useful technique for analysis, separation and enantioenrichment of chiral/racemic products. PMID:24875274

Yang, Xiaochuan; Wong, Shin Yee; Bwambok, David K; Atkinson, Manza B J; Zhang, Xi; Whitesides, George M; Myerson, Allan S

2014-07-18

143

Separation of flow from chiral magnetic effect in U+U collisions using spectator asymmetry  

CERN Document Server

We demonstrate that the prolate shape of the Uranium nucleus generates anti-correlation between spectator asymmetry and initial state ellipticity of the collision zone, providing a way to constrain the initial event shape in U+U collisions. As an application, we show that this can be used to separate the background contribution due to flow from the signals of chiral magnetic effect.

Chatterjee, Sandeep

2014-01-01

144

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

International Nuclear Information System (INIS)

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.

145

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

International Nuclear Information System (INIS)

We introduce a new approach for the separation of the electrostatic and magnetic components of the electron wave phase shift, based on the transport-of-intensity equation (TIE) formalism. We derive two separate TIE-like equations, one for each of the phase shift components. We use experimental results on FeCoB and Permalloy patterned islands to illustrate how the magnetic and electrostatic longitudinal derivatives can be computed. The main advantage of this new approach is the fact that the differences in the power spectra of the two phase components (electrostatic phase shifts often have significant power in the higher frequencies) can be accommodated by the selection of two different Tikhonov regularization parameters for the two phase reconstructions. The extra computational demands of the method are more than compensated by the improved phase reconstruction results. - Highlights: • We provide a new way to separate electrostatic and magnetic phase shifts in Lorentz microscopy. • We derive two new transport-of-intensity style equations, one for electrostatic phase shifts and the other for magnetic phase shifts. • We provide a new way to determine the longitudinal intensity derivative that automatically includes time reversal symmetry. • This approach allows for the Tikhonov regularization parameter to be selected for each phase shift separately. • We provide two example application on Permalloy and CoFeB patterned islands

146

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

Science.gov (United States)

The industrial history in the district of Linares (Spain) has had a severe impact on soil quality. Here we examined soil contaminated by lead and other heavy metals in "La Cruz" site, a brownfield affected by metallurgical residues. Initially, the presence of contaminants mainly associated with the presence of lead slag fragments mixed with the soil was evaluated. The subsequent analysis showed a quasi-uniform distribution of the pollution irrespective of the grain-size fractions. This study was accompanied by a characterization of the lead slag behavior under the presence of a magnetic field. Two main magnetic components were detected: first a ferromagnetic and/or ferrimagnetic contribution, second a paramagnetic and/or antiferromagnetic one. It was also established that the slag was composed mainly of lead spherules and iron oxides embedded in a silicate matrix. Under these conditions, the capacity of magnetic separation to remove pollutants was examined. Therefore, two high intensity magnetic separators (dry and wet devices, respectively) were used. Dry separation proved to be successful at decontaminating soil in the first stages of a soil washing plant. In contrast, wet separation was found effective as a post-process for the finer fractions. PMID:23357508

Sierra, C; Martínez, J; Menéndez-Aguado, J M; Afif, E; Gallego, J R

2013-03-15

147

Analysis of phase separation by thermal aging in duplex stainless steels by magnetic methods  

International Nuclear Information System (INIS)

The phase separation in ferrite phase of duplex stainless steel is the primary cause of thermal aging embrittlement of the LWR primary pressure boundary components. In this study the phase separation of simulated duplex stainless steel was detected by Mossbauer spectroscopy and magnetic property analysis by VSM (Vibrating Specimen Magnetometer). The simulated duplex stainless steels, Fe-Cr binary, Fe-Cr-Ni Temary, and Fe-Cr-Ni-Si quaternary alloys, were aged at 370 and 400 deg C up to 5,340 hours. It was observed from Mossbauer spectra analysis that internal magnetic field increases with aging time and from VSM that the specific saturation magnetization and Curie temperature increase with aging time. These results are indicative that phase separation into Fe-rich region and Cr-rich region is caused by thermal aging in the temperature range of 370 - 400 deg C. In cases specimens containing Ni, the increase of specific saturation magnetization is much higher. This implies that Ni seems to promote Fe-Cr interdiffusion, which accelerates the phase separation into Fe-rich ? phase and Cr-rich ?' phase. (author)

148

Analysis of phase separation by thermal aging in duplex stainless steels by magnetic methods  

Energy Technology Data Exchange (ETDEWEB)

The phase separation in ferrite phase of duplex stainless steel is the primary cause of thermal aging embrittlement of the LWR primary pressure boundary components. In this study the phase separation of simulated duplex stainless steel was detected by Mossbauer spectroscopy and magnetic property analysis by VSM (Vibrating Specimen Magnetometer). The simulated duplex stainless steels, Fe-Cr binary, Fe-Cr-Ni Temary, and Fe-Cr-Ni-Si quaternary alloys, were aged at 370 and 400 deg C up to 5,340 hours. It was observed from Mossbauer spectra analysis that internal magnetic field increases with aging time and from VSM that the specific saturation magnetization and Curie temperature increase with aging time. These results are indicative that phase separation into Fe-rich region and Cr-rich region is caused by thermal aging in the temperature range of 370 - 400 deg C. In cases specimens containing Ni, the increase of specific saturation magnetization is much higher. This implies that Ni seems to promote Fe-Cr interdiffusion, which accelerates the phase separation into Fe-rich {alpha} phase and Cr-rich {alpha}` phase. (author).

Kim, S. K.; Jae, W. M.; Kim, Y. S. [Hanyang Univ., Seoul (Korea, Republic of)

1997-10-01

149

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.'

150

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

Energy Technology Data Exchange (ETDEWEB)

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{sub 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., E-mail: kondokay@gmail.co [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan); Jin, T.; Miura, O. [Graduate School of Science and Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397 (Japan)

2010-11-01

151

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.

152

Gravitational and magnetic separation in self-assembled clay-ferrofluid nanocomposites  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english We report on experimental observations of self-assemblies in colloidal dispersions of clay nanoplatelets and magnetic nanoparticles. Visual observations have been combined with small angle X-ray scattering (SAXS) in the study of several composites at a fixed clay concentration in the dilute regime, [...] and varying ferrofluid concentrations. Our visual observations which encompass macroscopic separation in gravitational- and magnetic field, indicate that all samples present a concentrated phase and a diluted one. SAXS data obtained from each phase are consistent with the interpretation that the scattering contribution from the clay nano-platelets in the samples can be neglected in comparison with the magnetic particle contribution. The analysis of the scattered intensity is performed combining two models, one based on the global scattering function and the other allowing the extraction of the structure factor of the mixtures. The parameters of the size distribution of magnetic nanoparticles determined by both methods are in good agreement. The structure factor of the mixtures shows that on a local scale, the mixtures behave like a gas of isolated magnetic nanoparticles. It also indicates the presence of interactions between magnetic nanoparticles mediated by the presence of Laponite platelets. Such interactions could be attributed with a progressive partial phase separation between spheres and discs rather than to the formation of dense aggregates.

F.L.O., Paula; G.J. da, Silva; R., Aquino; J., Depeyrot; J.O., Fossum; K.D., Knudsen; G., Helgesen; F.A., Tourinho.

2009-04-01

153

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

154

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

Science.gov (United States)

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

Giakisikli, Georgia; Anthemidis, Aristidis N

2013-07-30

155

Magnetically Separable and Sustainable Nanostructured Catalysts for Heterogeneous Reduction of Nitroaromatics  

Directory of Open Access Journals (Sweden)

Full Text Available This review is focused on the strategies and designs of magnetic nanostructured catalysts showing the enhanced and sustainable catalytic performances for the heterogeneous reduction of nitoaromatics. Magnetic catalysts have the benefits of easy recovery and reuse after the completion of the reactions and green chemical processes. Magnetic separation, among the various procedures for removing catalysts, not only obviates the requirement of catalyst filtration or centrifugation after the completion of reactions, but also provides a practical technique for recycling the magnetized nanostructured catalysts. Consequently, discussions will address the methodologies and exemplars for the reusable magnetic composite catalysts. Because the synthesis of ideal magnetic nanostructured catalysts is of primary importance in the development of high-quality sustainable processes, the designs, preparation methods and recyclability of various recoverable magnetic nanostructured catalysts are emphasized. The representative methods and strategies for the synthesis of durable and reusable magnetic nanostructured catalysts are highlighted. The advantages, disadvantages, recyclability and the efficiency of the introduced heterogeneous systems have been explored in the reduction of nitrobenzene derivatives.

Mohammadreza Shokouhimehr

2015-03-01

156

Challenge to the volume reduction of contaminated soil based on magnetic separation  

International Nuclear Information System (INIS)

A great amount of radioactive substances were released in the neighborhood of Fukushima Daiichi Nuclear Power Station following the accident of this plant. In particular, damage from radioactive cesium (134 or 137) has become the main case of trouble, incurring the necessity of decontamination of soil in the contaminated territory. In addition, a large amount of contaminated soil was generated due to the decontamination work, and its volume reduction has become a large challenge for the management and storage. This paper takes up magnetic separation technology as one of the technologies of volume reduction, and introduces its development condition. In this method, soil is firstly classified by size, and clay (or silt) with small particles, which adsorbs about 80% of radioactive cesium in soil, is separated from sand gravel. Furthermore, this clay portion is separated based on magnetic separation to 1:1 type and 1:2 type clay minerals with different magnetic susceptibilities, for the purpose of volume reduction. This paper describes the principle of the above method, as well as the development history to date. (A.O.)

157

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

International Nuclear Information System (INIS)

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

158

Development and creation of the electromagnetic separator for isotope separation in the system of opposing axisymmetric magnetic fields with two fields reversed  

International Nuclear Information System (INIS)

The paper reports the results of work on creation of a setup for isotope separation in the system of opposing axisymmetric magnetic fields with two field reverses. Consideration is given to a real possibility of improving the efficiency of the electromagnetic separator and its resolving power in the double-reverse magnetic field system. It is demonstrated that the use of the opposing axisymmetric field system may substantially reduce the energy consumption during the process of isotope separation. The estimated magnetic field of the facility attests to a possibility of molybdenum isotope separation and isolation of high-purity 98Mo and 100Mo isotopes required for production of the 99Mo/99Tc generator, most widely used in modern medicine.

159

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

Science.gov (United States)

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 ø 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.

Shi, Yi; Wu, Yu; Li, Shaolei

2008-10-01

160

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

International Nuclear Information System (INIS)

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 ?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 ?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-shapander micro-electromagnet with mesh-shaped winding profile produces the strongest magnetic field (about 2.7 ?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

161

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

Science.gov (United States)

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 ?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 ?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 ?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; Samper, Victor; Poenar, Daniel; Yu, Chen

2004-10-01

162

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

Science.gov (United States)

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

Murad, S.

2006-01-01

163

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

Science.gov (United States)

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

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

2014-12-01

164

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

165

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

166

Treatment of heavy metals and radionuclides in groundwater and wastewater by magnetic separation  

International Nuclear Information System (INIS)

Removal of trace quantities of heavy metal or radionuclide contamination from solutions at high flow rate presents a considerable technical challenge. Low flow methods of treatment such as particle gravity settling require expensive large volume equipment, whereas traditional methods of filtration demand significant energy costs. Magnetic filtration can be used to provide a low cost method of solid-liquid separation at high flow rate, provided contaminants can be selectively bound to a magnetic solid particle. This paper describes recent progress with this technique including performance tests of composite materials produced to selectively remove specific contaminants such as cesium, uranium, lead, cadmium, and mercury from solution

167

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

168

A continuous, hybrid field-gradient device for magnetic colloid-based separations  

International Nuclear Information System (INIS)

A fully continuous, hybrid field-gradient device is developed for colloidal magnetic affinity separation. The device consists of a 1.0 cm internal diameter 1.2 m long, axially rotating horizontal glass chamber, with four repeating magnetic units distributed axially along the tube. Each magnetic unit consists of a stationary alternating-current solenoid that surrounds the chamber, followed by a direct current flowing, computer-controlled electromagnet, placed at a distance of 4.0 cm from the end of the solenoid. The alternating-current-carrying solenoids impart translational and rotary oscillations to the magnetic particles, enhancing mixing. The computer-controlled electromagnets draw the magnetic particles to the chamber walls, and increase their residence time in the chamber. By manipulating the on-off cycle for these electromagnets, the exiting solution can be switched between one that contains a negligible concentration of target-bound magnetic particles and one that has a high concentration of the target, without interrupting the feed. The operation of this device is demonstrated for the removal of cadmium ions from a cadmium sulfate solution. 1-10 ?m diameter anion-exchange-resin-coated magnetic particles at a concentration of 0.5 mg particles/ml were used as the mobile solid support. The feed consisted of a 10.0 mg/l cadmium sulfate solution, at a flow rate of 25 ml/min. The device was operated as a three-stage cross-current cascade. For this system, 45%, 58% rrent cascade. For this system, 45%, 58% and 63% of the entering cadmium ions are removed at each stage, respectively, with stage efficiencies that vary between 57% and 65%. Thus, more than 90% of the entering cadmium ions are removed. While this device has been demonstrated for metal ion removal from an aqueous feed, it can potentially be applied to several other affinity-based separations

169

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

Science.gov (United States)

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

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

2014-04-01

170

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

Science.gov (United States)

The unique properties of graphene and carbon nanotubes made them the most promising nanomaterials attracting enormous attention, due to the prospects for applications in various nanodevices, from nanoelectronics to sensors and energy conversion devices. Here we report on a novel deterministic, single-step approach to simultaneous production and magnetic separation of graphene flakes and carbon nanotubes in an arc discharge by splitting the high-temperature growth and low-temperature separation zones using a non-uniform magnetic field and tailor-designed catalyst alloy, and depositing nanotubes and graphene in different areas. Our results are very relevant to the development of commercially-viable, single-step production of bulk amounts of high-quality graphene. PMID:20714656

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

2010-10-01

171

Fingerprints of intrinsic phase separation in magnetically-doped 2DEG  

Science.gov (United States)

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

Terletska, Hanna; Dobrosavljevic, Vladimir

2009-03-01

172

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

CERN Document Server

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

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

2007-01-01

173

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

OpenAIRE

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 functio...

Raed Abu-Reziq; Howard Alper

2012-01-01

174

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

International Nuclear Information System (INIS)

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

175

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

176

Optimization of yield in magnetic cell separations using nickel nanowires of different lengths.  

Science.gov (United States)

Ferromagnetic nanowires are shown to perform both high yield and high purity single-step cell separations on cultures of NIH-3T3 mouse fibroblast cells. The nanowires are made by electrochemical deposition in nanoporous templates, permitting detailed control of their chemical and physical properties. When added to fibroblast cell cultures, the nanowires are internalized by the cells via the integrin-mediated adhesion pathway. The effectiveness of magnetic cell separations using Ni nanowires 350 nm in diameter and 5-35 micrometers long in field gradients of 40 T/m was compared to commercially available superparamagnetic beads. The percent yield of the separated populations is found to be optimized when the length of the nanowire is matched to the diameter of the cells in the culture. Magnetic cell separations performed under these conditions achieve 80% purity and 85% yield, a 4-fold increase over the beads. This effect is shown to be robust when the diameter of the cell is changed within the same cell line using mitomycin-C. PMID:15801791

Hultgren, Anne; Tanase, Monica; Felton, Edward J; Bhadriraju, Kiran; Salem, Aliasger K; Chen, Christopher S; Reich, Daniel H

2005-01-01

177

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

178

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.

179

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}m in the final roasted product feeding to magnetic separation. Under these conditions, a magnetic concentrate containing 90.31% total iron and 89.76% metallization iron with a total iron recovery rate of 83.88% was obtained. In addition, mineralography of vanadium tailings, coal-based reduction product and magnetic concentrate were studied by X-ray powder diffraction technique (XRD). The microstructures of above products were analyzed by scanning electron microscope (SEM) to help understand the mechanism.

Yang Huifen, E-mail: yanghf@ustb.edu.cn [Key Laboratory for High-Efficient Mining and Safety of Metal Mines of Ministry of Education, University of Science and Technology Beijing, Beijing 100083 (China); Jing Lili [Key Laboratory for High-Efficient Mining and Safety of Metal Mines of Ministry of Education, University of Science and Technology Beijing, Beijing 100083 (China); Zhang Baogang [Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

2011-01-30

180

Reduction of the magnetic signal from unbound magnetic markers for magnetic immunoassay without bound/free separation  

International Nuclear Information System (INIS)

We investigated the effect of adding magnetic shielding and applying of a compensation field to reduce the magnetic signal from unbound free markers. When the initial immunoassay system was used without the additional shielding box, the signal intensity of the liquid markers normalized by the weight of the Fe3O4 was 1/2700 of the dried markers. By installing the additional shielding box, the reduction factor was improved to 1/10,000. We successfully reduced the magnetic signal of the liquid marker further by applying a compensation field. The magnetic signal of the free marker obtained by applying a compensation field of -18 nT was 1.4 m?0, which was close to the system noise level. Field compensation at the very local area just around the SQUID is sufficient for reducing of the magnetic signal from the free marker

181

Study of excess Fe metal in the lunar fines by magnetic separation, Moessbauer spectroscopy, and microscopic examination.  

Science.gov (United States)

A simple and convenient method of making quantitative magnetic separations has been applied to the lunar fines. The fractions obtained form groups containing distinctively different particle types; thus, it appears that magnetic separation in itself many be a useful way of characterizing lunar fines. Moessbauer studies of fines 10084 show that the metal cannot contain more than about 1.5% Ni, implying that by far the bulk of the metal results from reduction rather than from direct meteoritic addition. Microscopic examination of magnetic separates from 15101 fines suggests that reduction of Fe accompanies every major impact event on the moon.

Housley, R. M.; Grant, R. W.; Abdel-Gawad, M.

1972-01-01

182

Quantitative characterization of magnetic separators: Comparison of systems with and without integrated microfluidic mixers  

DEFF Research Database (Denmark)

We present two new types of microfluidic passive magnetic bead separator systems as well as methods for performing quantitative characterizations of them. Both systems consist of a microfluidic channel with long rectangular magnetic elements of permalloy that are placed by the sides of the channel and magnetized by an external magnetic field. In one of the systems, a staggered herringbone microfluidic mixer is integrated in the channel. The characterization of the systems includes magnetic measurements of the capture-and-release efficiencies, estimates of distributions of captured beads in a channel from micrographs, and simulations and analytical models of bead trajectories, capture efficiencies, and capture distributions. We show that the efficiencies of both systems compare favorably to those in the literature. For the studied geometries, the mixer is demonstrated to increase the bead capture-and-release efficiency for a fixed flow rate by up to a factor of two. Moreover, high capture efficiencies can be achieved in the system with mixer at up to ten times higher flow rates than in the system without mixer.

Lund-Olesen, Torsten; Bruus, Henrik

2006-01-01

183

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.

184

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.

185

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

International Nuclear Information System (INIS)

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

186

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

187

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

188

Charge separation effects in magnetized electron-ion plasma expansion into a vacuum  

CERN Document Server

Charge separation effects in the expansion of magnetized relativistic electron-ion plasmas into a vacuum are examined using 2-1/2-dimensional particle-in-cell plasma simulations. The electrostatic field at the plasma surface decelerates electrons and accelerates ions. A fraction of the surface electrons are trapped and accelerated by the pondermotive force of the propagating electromagnetic pulse, a mechanism we call the DRPA (diamagnetic relativistic pulse accelerator). This charge separation is enhanced as the initial plasma temperature is decreased. The overall energy gain of the plasma particles through the expansion strongly depends on the initial plasma temperature. Moreover, the electrons become relatively less energized and the ions more energized as the plasma temperature decreases.

Nishimura, K; Gary, S P; Nishimura, Kazumi; Liang, Edison

2003-01-01

189

Synthesis of new type of Au-magnetic nanocomposite and application for protein separation thereof  

Science.gov (United States)

We present a different strategy for synthesizing the Au-?-Fe2O3 bifunctional nanoparticle by using a larger (50 nm) Au nanoparticle as the core surrounded by smaller (10 nm) ?-Fe2O3 nanoparticles. The synthesis of the composite nanoparticles is quite facile based on a simple redox process whereby Fe2+ is used to reduce Au3+. The morphology and composition of the product is measured by transmission electron microscopy, X-ray powder diffraction and UV-vis spectroscopy. We demonstrate the utility of these as-prepared Au-?-Fe2O3 nanoparticles by showing they can be used to separate proteins in solution. For example, bovine serum is efficiently removed from an aqueous solution with the simple addition of the NPs and application of a small magnet. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis is performed to evaluate the fidelity and efficiency of the protein separation procedure.

Song, Yu; Tao, Ling; Shen, Xiangchun

2012-07-01

190

Charge separation effects in magnetized electron-ion plasma expansion into a vacuum  

International Nuclear Information System (INIS)

Charge separation effects in the expansion of magnetized relativistic electron-ion plasmas into a vacuum are examined using 2(1/2)-dimensional particle-in-cell plasma simulations. The electrostatic field at the plasma surface decelerates electrons and accelerates ions. A fraction of the surface electrons is trapped and accelerated by the pondermotive force of the propagating electromagnetic pulse, a mechanism we call the diamagnetic relativistic pulse accelerator. This charge separation is enhanced as the initial plasma temperature is decreased. The overall energy gain of the plasma particles through the expansion strongly depends on the initial plasma temperature. Moreover, the electrons become relatively less energized and the ions more energized as the plasma temperature decreases

191

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

Science.gov (United States)

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

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

2011-11-01

192

Rapid detection and purification of sequence specific DNA binding proteins using magnetic separation  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a method for the rapid identification and purification of sequence specific DNA binding proteins based on magnetic separation is presented. This method was applied to confirm the binding of the human recombinant USF1 protein to its putative binding site (E-box within the human SOX3 protomer. It has been shown that biotinylated DNA attached to streptavidin magnetic particles specifically binds the USF1 protein in the presence of competitor DNA. It has also been demonstrated that the protein could be successfully eluted from the beads, in high yield and with restored DNA binding activity. The advantage of these procedures is that they could be applied for the identification and purification of any high-affinity sequence-specific DNA binding protein with only minor modifications.

TIJANA SAVIC

2006-02-01

193

Separation of Selenite from Inorganic Selenium Ions using TiO2 Magnetic Nanoparticles  

International Nuclear Information System (INIS)

A simple and quick separation technique for selenite in natural water was developed using TiO2 SiO2/Fe3O4 nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the TiO2 shell. The synthesized nanoparticles were used to separate selenite (Se4+) in the presence of Se6+ or selenium anions for the photocatalytic reduction to Se0 atom on the TiO2 shell, followed by magnetic separation using Fe3O4 nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis

194

Fabrication of magnetically separable palladium-graphene nanocomposite with unique catalytic property of hydrogenation  

Science.gov (United States)

One step solvothermal route has been developed to prepare a well dispersed magnetically separable palladium-graphene nanocomposite, which can act as a unique catalyst against hydrogenation due to the uniform decoration of palladium nanoparticles throughout the surface of the magnetite-graphene nanocomposite and hence can be reused for several times. In addition to catalytic activity, palladium nanoparticles also facilitate the formation and homogeneous distribution of magnetite (Fe 3O 4) nanoparticles onto the graphene surfaces or else an agglomerated product has been obtained after the solvothermal reduction of graphene oxide in presence of Fe 3+ alone.

Chandra, Sourov; Bag, Sourav; Das, Pradip; Bhattacharya, Dipsikha; Pramanik, Panchanan

2012-01-01

195

Steelmaking slag beneficiation by magnetic separator and impacts on sinter quality  

Directory of Open Access Journals (Sweden)

Full Text Available Basic oxygen furnaces (BOF slag is the main problem at all iron and steel factories. About more than 6 million tons/year of BOF slag has been accumulated from the waste stockyards in Turkey. Dumps slags can be revaluated by a processing technology which makes it possible to obtain products that meet the requirements of sintering and blast furnace production. The slags with particle size of -10 mm were enriched by the magnetic separator resulting and increase in Fe grade from 18% to 33%. The use of BOF slag in sinter blend provided additional Mn, CaO, MgO and introduced a good solution to environmental problems.

Bölükba?? Ö.S.

2014-01-01

196

Magnetism and Phase Separation in the Ground State of the Hubbard Model  

CERN Document Server

We discuss the ground state magnetic phase diagram of the Hubbard model off half filling within the dynamical mean-field theory. The effective single-impurity Anderson model is solved by Wilson's numerical renormalization group calculations, adapted to symmetry broken phases. We find a phase separated, antiferromagnetic state up to a critical doping for small and intermediate values of U, but could not stabilise a Neel state for large U and finite doping. At very large U, the phase diagram exhibits an island with a ferromagnetic ground state. Spectral properties in the ordered phases are discussed.

Zitzler, R; Bulla, R; Pruschke, Th.

2002-01-01

197

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

198

Heterostructured magnetite-titanate nanosheets for prompt charge selective binding and magnetic separation of mixed proteins.  

Science.gov (United States)

We reported the prompt charge selective binding and magnetic separation of mixed proteins by utilizing heterostructured Fe3O4-Na2Ti3O7 nanosheets. Fe3O4-Na2Ti3O7 nanosheets are found to combine a variety of structure and property merits, such as the increased interlayer galleries, exposed exchange sites, flexible framework, and magnetic manipulability. Probing the dissociation dynamics of Na(+) inside the nanosheets reveals that they possess remarkably enhanced Na(+) dissociation capability and the dissociation rate of Na(+) reaches 7.9×10(-)(6)mol g(-)(1)s(-)(1), much superior to titanate nanotubes. In model protein separation experiments, we utilize mixed proteins containing albumin and hemoglobin to assess Fe3O4-Na2Ti3O7 nanosheets. It is found that, by controlling the pH of the sample at 6, positively charged hemoglobin and negatively charged albumin are immediately separated (?5s) by the nanosheets and the saturated loading capacity of hemoglobin on the nanosheets reaches 4.7±0.61g g(-)(1). Furthermore, hemoglobin bound to the nanosheets can be readily released after buffer wash and is not damaged, while the nanosheets are recyclable and maintain their high efficiency. The outstanding performance of Fe3O4-Na2Ti3O7 nanosheets in separating mixed proteins is attributed to the ultrafast Na(+) dissociation rate, flexible titanate framework, open geometry, and aqueous-like environment to stabilize proteins. These merits, together with the recyclability and cost effectiveness, should make Fe3O4-Na2Ti3O7 nanosheets ideal candidates for biological recognition, isolation, and purification under technologically useful conditions. PMID:24267329

Zhou, Qinhua; Lu, Zhufeng; Cao, Xuebo

2014-02-01

199

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

Science.gov (United States)

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

200

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

International Nuclear Information System (INIS)

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

201

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

International Nuclear Information System (INIS)

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.

202

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

International Nuclear Information System (INIS)

Highlights: • Microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite. • The mineral processing properties of microwave treated ilmenite were generally as good as or better than that of initial ilmenite. • 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. - Abstract: 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

203

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: • Microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite. • The mineral processing properties of microwave treated ilmenite were generally as good as or better than that of initial ilmenite. • 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. - Abstract: 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 [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Srinivasakannan, C. [Chemical Engineering Program, The Petroleum Institute, Abu Dhabi, P.O. Box 253 (United Arab Emirates); Chen, Guo, E-mail: guochen@kmust.edu.cn [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Chemical Engineering Program, The Petroleum Institute, Abu Dhabi, P.O. Box 253 (United Arab Emirates); Peng, Jinhui, E-mail: jhpeng@kmust.edu.cn [National Local Joint Laboratory of Engineering Application of Microwave Energy and Equipment Technology, Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Chemical Engineering Program, The Petroleum Institute, Abu Dhabi, P.O. Box 253 (United Arab Emirates)

2014-05-01

204

Intensive ion beams in the transverse magnetic field of an electromagnetic separator  

International Nuclear Information System (INIS)

Based on state-of-the-art knowledge, the processes of the formation of intense ion beams in the transverse magnetic field of a commercial electromagnetic separator are analyzed. It is shown that, given the conditions of closed electron drift, the potentials will surely equalize along the fast ion trajectories all the way through the beam length; hence, no improvement in dynamic decompensation is caused by the low-frequency noise of the source. It is established that increasing the full beam current forces the maximum amplitude of the current density oscillations out to the beam periphery crosswise. For the first time, it is shown that suppressing noise oscillations in the arc discharge of an ion source for the formation of a highly stable ion beam with a minimum inner potential drop is possible. At low pressures, with collective interaction out of play, the drop is determined by Coulomb's collisions between the beam particles and compensating electrons. The analysis of collective phenomena likely to occur in the ion-beam plasma of a separator gives evidence of an experimental space potential buildup with increasing residual gas pressure in the calutron, leading to a high-frequency ion-electron beam instability. It is pointed out that this instability combined with an additional decompensation results in a noticeable broadening of the beam energy spectrum, which in turn makes for a lower quality of separation

205

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

206

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

Science.gov (United States)

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

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

2014-12-01

207

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

International Nuclear Information System (INIS)

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

208

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

Science.gov (United States)

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

Xie, Changkun

209

Superconducting Open-Gradient Magnetic Separation for the Pretreatment of Radioactive or Mixed Waste Vitrification Feeds  

International Nuclear Information System (INIS)

An open-gradient magnetic separation (OGMS) process is being considered to separate deleterious elements from radioactive and mixed waste streams prior to vitrification or stabilization. By physically segregating solid wastes and slurries based on the magnetic properties of the solid constituents, this potentially low-cost process may serve the U.S. Department of Energy (DOE) by reducing the large quantities of glass produced from defense-related high-level waste (HLW). Furthermore, the separation of deleterious elements from low-level waste (LLW) also can reduce the total quantity of waste produced in LLW immobilization activities. Many HLW 'and LLW waste' streams at both Hanford and the Savannah River Site (SRS) include constituents deleterious to the durability of borosilicate glass and the melter many of the constituents also possess paramagnetism. For example, Fe, Cr, Ni, and other transition metals may limit the waste loading and affect the durability of the glass by forming spine1 phases at the high operating temperature used in vitrification. Some magnetic spine1 phases observed in glass formation are magnetite (Fe,O,), chromite (FeCrO,), and others [(Fe, Ni, Mg, Zn, Mn)(Al, Fe, Ti, Cr)O,] as described elsewhere [Bates-1994, Wronkiewicz-1994]. Stable spine1 phases can cause segregation between the glass and the crystalline phases. As a consequence of the difference in density, the spine1 phases tend to accumulate at the bottom of the glass melter, which decreae bottom of the glass melter, which decreases the conductivity and melter lifetime [Sproull-1993]. Crystallization also can affect glass durability [Jantzen-1985, Turcotte- 1979, Buechele-1990] by changing the chemical composition of the matrix glass surrounding the crystals or causing stress at the glass/crystal interface. These are some of the effects that can increase leaching [Jantzen-1985]. A SRS glass that was partially crystallized to contain 10% vol. crystals composed of spinels, nepheline, and acmite phases showed minimal changes in short term leachability [Jantzen-1985, Hench-1982]. However, Jantzen et.al. found that leaching increased preferentially at grain boundary interfaces [Jantzen-1985]. For a SRL 165 glass crystallized up to 30% vol., leachability measured by normalized boron release increased by a factor of three compared to the uncrystallized glass [Kelly-1975, Plodinec-1979]. In general, the magnitude of the crystallization effect depends highly on glass composition and cooling rate

210

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

International Nuclear Information System (INIS)

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 os, 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.

211

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.

212

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

Science.gov (United States)

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; Nakai, Yuki; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

2013-01-01

213

Photocatalytic degradation of methylene blue on magnetically separable MgFe2O4 under visible light irradiation  

International Nuclear Information System (INIS)

A magnetically separable single-phase MgFe2O4 photocatalyst with a spinel crystal structure was synthesized by using the solid-state reaction method. The formation of spinel structure is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic measurements showed that the photocatalyst material can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for waste water treatment. The photocatalytic activity of MgFe2O4 was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe2O4 was studied by measuring their photocurrent–potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm?2 illumination. - Graphical abstract: Highly efficient magnetically separable MgFe2O4 photocatalyst for organic based impurities decomposition as well as for the production of H2 gas was synthesized and characterized successfully (a) MgFe2O4 photocatalyst in polluted water, (b) The photocatalyst (MgFe2O4) is being attracted toward magnetic field for separation, (c) Hysteresis loop of MgFe2O4 showing magnetic behavior. Highlights: ? New photocatalyst working in the visible range have been synthesized by facile cheap route. ? MgFe2O4 photocatalyst showed well defined magnetically separable behavior. ? Excellent water splitting characteristics to produce H2 was observed under visible light irradiation

214

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 1.78 mmol/g and the average diameter of 21.6 nm 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 36.36 mg/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 0.01 mol/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

215

Semi-continuous in situ magnetic separation for enhanced extracellular protease productionmodeling and experimental validation  

DEFF Research Database (Denmark)

In modern biotechnology proteases play a major role as detergent ingredients. Especially the production of extracellular protease by Bacillus species facilitates downstream processing because the protease can be directly harvested from the biosuspension. In situ magnetic separation (ISMS) constitutes an excellent adsorptive method for efficient extracellular protease removal during cultivation. In this work, the impact of semi?continuous ISMS on the overall protease yield has been investigated. Results reveal significant removal of the protease from Bacillus licheniformis cultivations. Bacitracin?functionalized magnetic particles were successfully applied, regenerated and reused up to 30 times. Immediate reproduction of the protease after ISMS proved the biocompatibility of this integrated approach. Six subsequent ISMS steps significantly increased the overall protease yield up to 98% because proteolytic degradation and potential inhibition of the protease in the medium could be minimized. Furthermore, integration of semi?continuous ISMS increased the overall process efficiency due to reduction of the medium consumption. Process simulation revealed a deeper insight into protease production, and was used to optimize ISMS steps to obtain the maximum overall protease yield. Biotechnol. Bioeng. 2013; 110: 2161–2172. © 2013 Wiley Periodicals, Inc.

Cerff, M.; Scholz, A.

2013-01-01

216

Residual Separation of Magnetic Fields Using a Cellular Neural Network Approach  

Science.gov (United States)

- In this paper, a Cellular Neural Network (CNN) has been applied to a magnetic regional/residual anomaly separation problem. CNN is an analog parallel computing paradigm defined in space and characterized by the locality of connections between processing neurons. The behavior of the CNN is defined by the template matrices A, B and the template vector I. We have optimized weight coefficients of these templates using Recurrent Perceptron Learning Algorithm (RPLA). The advantages of CNN as a real-time stochastic method are that it introduces little distortion to the shape of the original image and that it is not effected significantly by factors such as the overlap of power spectra of residual fields. The proposed method is tested using synthetic examples and the average depth of the buried objects has been estimated by power spectrum analysis. Next the CNN approach is applied to magnetic data over the Golalan chromite mine in Elazig which lies East of Turkey. This area is among the largest and richest chromite masses of the world. We compared the performance of CNN to classical derivative approaches.

Albora, A. M.; Özmen, A.; Uçan, O. N.

217

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

International Nuclear Information System (INIS)

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

218

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

Science.gov (United States)

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

Nam, Seung-Il

2010-08-01

219

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

Directory of Open Access Journals (Sweden)

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

Chimma Pattamawan

2010-02-01

220

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

Science.gov (United States)

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

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

2007-04-15

221

Spatiotemporally separating electron and phonon thermal transport in L10 FePt films for heat assisted magnetic recording  

International Nuclear Information System (INIS)

We report the spatio-temporal separation of electron and phonon thermal transports in nanostructured magnetic L10 FePt films at the nanometer length scale and the time domain of tens of picosecond, when heated with a pulsed laser. We demonstrate that lattice dynamics measured using the picosecond time-resolved laser pump/X-ray probe method on the FePt (002) and Ag (002) Bragg reflections from different layers provided the information of nanoscale thermal transport between the layers. We also describe how the electron and phonon thermal transports in nanostructured magnetic thin films were separated.

222

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

223

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

224

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

Science.gov (United States)

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

Furlan, Marco; Lattuada, Marco

2012-08-28

225

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

International Nuclear Information System (INIS)

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

226

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

Directory of Open Access Journals (Sweden)

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

Sharma Bishwaram

2012-01-01

227

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

228

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

229

Equilibrium density of an electron-hole liquid in a strong magnetic field: A possibility of phase separation  

International Nuclear Information System (INIS)

The ground state of a model electron-hole liquid (EHL) in a strong magnetic field is investigated. In the regime when only a few Landau subbands are occupied the complex behavior of the equilibrium density leads to a possibility of phase separation. At certain magnetic-field strengths the EHL ground-state energy plotted as a function of the density has two local minima corresponding to two phases with different numbers of Landau subbands occupied. As a result the equilibrium density of EHL will have strong discontinuities as a function of the magnetic field, occurring whenever the relative strength of those minima changes. In a nonequilibrium system, such as a real electron-hole droplet, both phases may be present simultaneously. We discuss several luminescence and infrared absorption experiments, and suggest that they indicate such a phase separation

230

Use of the high-gradient magnetic separation on processing of mineral and man-caused raw stock  

International Nuclear Information System (INIS)

The role and the value of a high-gradient magnetic separation process in the improvement of concentration and hydrometallurgical processing of noble, non-ferrous, rare and radioactive metal ores are under consideration. The results of research and experiments are presented which are carried out by the laboratory of magnetic separation and special methods of ore enrichment the All-Russian Research Institute of Chemical Technology with the aim of development and introduction into the industry of ore processing technology for uranium, gold, nonferrous and rare metal bearing ores, quarts-feldspar as well as technogenic waste processing. The most promising applications of magnetic methods are determined. The unique methodological and technical achievements are offered for use

231

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

232

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

233

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

234

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

International Nuclear Information System (INIS)

'Vitrification has been selected as a final waste form technology in the US for long-term storage of high-level radioactive wastes (HLW). However, a foreseeable problem during vitrification in some waste feed streams lies in the presence of elements (e.g., transition metals) in the HLW that may cause instabilities in the final glass product. The formation of spinel compounds, such as Fe3O4 and FeCrO4, results in glass phase separation and reduces vitrifier lifetime, and durability of the final waste form. A superconducting open gradient magnetic separation (OGMS) system maybe suitable for the removal of the deleterious transition elements (e.g. Fe, Co, and Ni) and other elements (lanthanides) from vitrification feed streams due to their ferromagnetic or paramagnetic nature. The OGMS systems are designed to deflect and collect paramagnetic minerals as they interact with a magnetic field gradient. This system has the potential to reduce the volume of HLW for vitrification and ensure a stable product. In order to design efficient OGMS and High gradient magnetic separation (HGMS) processes, a fundamental understanding of the physical and chemical properties of the waste feed streams is required. Using HLW simulant and radioactive fly ash and sludge samples from the Savannah River Technology Center, Rocky Flats site, and the Hanford reservation, several techniques were used to characterize and predict the separation capability for a superconducting OGMS system.'

235

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

236

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

Science.gov (United States)

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

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

2012-09-01

237

Separation Anxiety  

Science.gov (United States)

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

Julie Yu

2007-01-01

238

Phase transitions in a ferrofluid at magnetic field induced microphase separation  

OpenAIRE

In the presence of a magnetic field applied perpendicular to a thin sample layer, a suspension of magnetic colloidal particles (ferrofluid) can form spatially modulated phases with a characteristic length determined by the competition between dipolar forces and short-range forces opposing density variations. We introduce models for thin-film ferrofluids in which magnetization and particle density are viewed as independent variables and in which the non-magnetic properties of...

Lacoste, D.; Lubensky, T. C.

2001-01-01

239

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

Science.gov (United States)

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

Singh, Surendra; Basu, Saibal

2009-02-01

240

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)

241

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

Science.gov (United States)

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

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

2014-08-01

242

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

Science.gov (United States)

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

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

2014-08-01

243

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

International Nuclear Information System (INIS)

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

244

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

Directory of Open Access Journals (Sweden)

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

Emmanuel Frenod

2002-01-01

245

Microstructure and magnetic properties of Gd-Hf-Co-Al glassy alloys by liquid-liquid phase separation  

International Nuclear Information System (INIS)

Phase separated glassy ribbons were prepared in the Gd-Hf-Co-Al system by rapid quenching of the melt. From the Gd55Co25Al20 ternary good glass former, we substitute Gd with Hf by 10, 20, 27.5, 35, 45 and 55 at. %. Due to the strong positive enthalpy of mixing between the principal elements Gd and Hf (?Hmix = +11kJ/mole) a heterogeneous microstructure is formed consisting of two amorphous phases Gd-enriched and Hf-enriched. For the alloys with clearly phase separated microstructure, nano-meter scale (100nm) secondary phase separation is observed in each amorphous phase. In the case of the Gd27.5Hf27.5Co25Al20 alloy, coexistence of two different types of microstructure such as a droplet-like and interconnected structure were observed from the areas having different cooling rate. This microstructure evolution is in good agreement with calculation results by Lattice Boltzmann method. On the other hand, measured magnetic properties show the composition and volume fraction dependence of magnetization and transition temperature (Tc) of Gd-Hf-Co-Al system. The saturation magnetization decreases as a function of Hf contents and can be described by a simple mixture model.

246

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

Science.gov (United States)

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

Ghasemi, Ensieh; Sillanpää, Mika

2015-01-01

247

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

Science.gov (United States)

Magnetophoresis—the motion of magnetic particles under applied magnetic gradient—is a process of great interest in novel applications of magnetic nanoparticles and colloids. In general, there are two main different types of magnetophoresis processes: cooperative magnetophoresis (a fast process enhanced by particle-particle interactions) and noncooperative magnetophoresis (driven by the motion of individual particles in magnetic fields). In the case of noncooperative magnetophoresis, we have obtained a simple analytical solution which allows the prediction of the magnetophoresis kinetics from particle characterization data (size and magnetization). Our comparison with new experimental results shows good quantitative agreement. In addition, we show the existence of a universal curve onto which all experimental results should collapse after proper rescaling. The range of applicability of the analytical solution is discussed in light of the predictions of a magnetic aggregation model [Soft MatterJAPIAU1744-683X10.1039/c0sm01424a 7, 2336 (2011)].

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

2011-08-01

248

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

Science.gov (United States)

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

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

2015-01-01

249

Bimodal properties of a patterned magnetic nanostructure: Separation of individual components’ contributions  

International Nuclear Information System (INIS)

We study the properties of magnetic islands with perpendicular magnetization (dots), hundred nanometres in lateral size, embedded in a magnetic matrix, by magneto-optical method exploiting Kerr effect and magnetic force microscopy. Due to a complex structure the investigated patterned system displays a bimodal character. In order to gain an insight into behaviour of the components we apply a simple approach for decomposition of bimodal hysteresis loops obtained from magneto-optical measurements. The hysteresis loops of subsystems are determined from the field dependent rotation of a plane polarization and ellipticity of a laser beam reflected from the sample surface. Comparison with the adequate reference samples reveals differences in the behaviour of the patterned system resulting from confined size of the dots and their dipole coupling with the matrix. Magnetization reversal mechanisms of the individual components are discussed in details. - Highlights: • Magnetic nanoislands with perpendicular magnetization are studied by MOKE and MFM. • A simple model to extract magnetic properties of the system components is used. • Fitting conditions of the component hysteresis loops are discussed. • Magnetization reversal of the nanoislands and the matrix and their coupling are deduced

250

Bimodal properties of a patterned magnetic nanostructure: Separation of individual components’ contributions  

Energy Technology Data Exchange (ETDEWEB)

We study the properties of magnetic islands with perpendicular magnetization (dots), hundred nanometres in lateral size, embedded in a magnetic matrix, by magneto-optical method exploiting Kerr effect and magnetic force microscopy. Due to a complex structure the investigated patterned system displays a bimodal character. In order to gain an insight into behaviour of the components we apply a simple approach for decomposition of bimodal hysteresis loops obtained from magneto-optical measurements. The hysteresis loops of subsystems are determined from the field dependent rotation of a plane polarization and ellipticity of a laser beam reflected from the sample surface. Comparison with the adequate reference samples reveals differences in the behaviour of the patterned system resulting from confined size of the dots and their dipole coupling with the matrix. Magnetization reversal mechanisms of the individual components are discussed in details. - Highlights: • Magnetic nanoislands with perpendicular magnetization are studied by MOKE and MFM. • A simple model to extract magnetic properties of the system components is used. • Fitting conditions of the component hysteresis loops are discussed. • Magnetization reversal of the nanoislands and the matrix and their coupling are deduced.

Sveklo, I. [Faculty of Physics, University of Bia?ystok, ul. Lipowa 41, 15-424 Bia?ystok (Poland); Kupala State University, Ozheshko str. 22, Grodno 230023 (Belarus); Kurant, Z.; Maziewski, A. [Faculty of Physics, University of Bia?ystok, ul. Lipowa 41, 15-424 Bia?ystok (Poland); Sieczkowska, E.; Petroutchik, A.; Baczewski, L.T. [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Wawro, A., E-mail: wawro@ifpan.edu.pl [Institute of Physics Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland)

2013-11-15

251

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

252

Phase separation, ferromagnetism and magnetic irreversibility in La1-xSrxMn1-yFeyO3  

International Nuclear Information System (INIS)

Magnetic susceptibility, ?(T), is investigated in ceramic La1-xSrxMn1-yFeyO3 (LSMFO) samples with x=0.3 and y=0.15-0.25. A ferromagnetic (FM) transition observed in LSMFO is accompanied with an appreciable decrease of the transition temperature with increasing y, which is connected to breaking of the FM double-exchange interaction by doping with Fe. Strong magnetic irreversibility, observed in low (B=10 G) field, gives evidence for frustration of the magnetic state of LSMFO. The FM transition, which is expanded with increasing B, is more pronounced in the samples with y=0.15-0.20 and broadens considerably at y=0.25, where the irreversibility is increased. Well above the transition, ?(T) exhibits a Curie-Weiss asymptotic behavior, yielding very large values of the effective Bohr magneton number per magnetic ion, incompatible with those of Mn or Fe single ions. At y=0.15 and 0.20 a critical behavior of ?-1(T)?(T/TC-1)? in the region of the FM transition is characterized by influence of two different magnetic systems, a 3D percolative one with ?=?p?1.8 and TC=TC(p), and a non-percolative 3D Heisenberg spin system, with ?=?H?1.4 and TC=TC(H), where TC(p)C(H). At y=0.25 the percolative contribution to the critical behavior of ?(The critical behavior of ?(T) is not observed. The dependence of ? on T and y gives evidence for phase separation, with onset already near the room temperature, leading to generation of nanosize FM particles in the paramagnetic host matrix of LSMFO. The ferromagnetism of LSMFO is attributable to percolation over the system of such particles and generation of large FM clusters, whereas the frustration is governed presumably by a system of smaller weakly-correlated magnetic units, which do not enter the percolative FM clusters. - Highlights: ? Low-field magnetic susceptibility of La1-xSrxMn1-yFeyO3 is investigated. ? Coexistence of ferromagnetism and magnetic irreversibility is observed. ? This is connected to influence of two different magnetic subsystems. ? Both of them exist due to nanosize ferromagnetic particles in paramagnetic matrix. ? Such effect of phase separation is an intrinsic property of manganites.

253

Subexponential Divergence and Diffusive Twist of Turbulent Magnetic Field Lines in the Limit of the Very Short Separations  

Science.gov (United States)

Turbulent magnetic field lines have long been thought to be diverging from each other (or converging toward each other) at exponential rates known as Lyapunov exponents. It is argued here that in a turbulent magnetized plasma, subexponential divergence (convergence) and diffusive twist better characterize the dispersal of magnetic field lines (MFLs) in the limit of the very small separations ? than do the usual Lyapunov exponents or exponentiation rates. In that limit of the very small separations, the field-line equations give a variation rate for ln?, not ?, and the implied log-normality of the ? distribution makes a much better probe of the exponential divergence of core MFLs. A fully nonlinear calculation shows that the separation logarithm, ln?, and twist or rotation angle, ??, between pairs of MFLs diffuse with the distance ?z elapsed along the main field, as soon as ?z exceeds min(k-1II,?II), the minimum of the parallel correlation length k-1II?L?? of the turbulent field gradients and of the associated nonlinear scale, ?II???, defined as the field-aligned length scale for which the mean cross-field displacement 1/2 reaches 21/2?k-1II?21/2L??, with kII the wavenumber where the turbulence spectrum becomes steeper than (k2?+?2k2?)-1 and ? the anisotropy parameter of the turbulence. The average growth of the core field-line separation ?0e1/2=e~(?z)1/2 along the direction of fastest growth, being subexponential, is not compatible with the definition of Lyapunov exponents. The largest exponentiation rate of the core MFLs actually decreases with the distance ?z. Application of the new nonlinear calculation to the solar wind shows a substantial MFL rotation in a plane transverse to the main field.

Ragot, B. R.

2008-08-01

254

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

CERN Document Server

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

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

2002-01-01

255

Maximizing haematite recovery within a fine and wide particle-size distribution using wet high-intensity magnetic separation  

Scientific Electronic Library Online (English)

Full Text Available The physical beneficiation of iron ore that has a wide particle-size distribution is problematic, regardless of the process applied, whether dense medium separation, gravity concentration, magnetic separation, or flotation. The problem of particle size is further compounded when there is a significa [...] nt -10 µm fraction. Generally the approach to a wide particle-size distribution is to split into narrower size ranges and treat each separately. More often than not the -10 µm fraction is not treated but discarded. This approach results in a more complicated and expensive flow sheet and the loss of any potential value in the -10 µm fraction. Wet high-intensity magnetic separation (WHIMS) bench-scale test work was conducted on a haematite-rich material with a particle size of -200 µm What made this material different was that it contained a 60% -10 µm fraction, hence discarding the -10 µm material was not an option. The objective of the test work was to determine how to maximize the recovery of the haematite across the full particle size range. Given the unusual particle size distribution, it was concluded that WHIMS would be the only practical beneficiation route. The -200 +10 µm and -10 µm fractions were treated separately and together under varying WHIMS conditions. For a given concentrate grade, the mass yield obtained was greater when the total particle-size distribution was treated. The inferred optimum conditions, using the same material, were tested on a pilot-scale WHIMS and similar results were obtained.

M, Dworzanowski.

2014-07-01

256

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

257

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

258

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

Science.gov (United States)

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

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

2015-04-01

259

On-line system for separate field correction of the U-10 synchrotron magnetic units  

International Nuclear Information System (INIS)

The updated on-line system for individual connection of the field magnetic units of the U-10 synchrotron ring magnet is described. Modernization includes the change of rheostats for a current transistor requlators controlled by a computer. 96 current regulators with control electronics frames are placed in the ''Vishnya'' console. The system permits to increase synchrotron acceptance for the injection moment approximately 1.5 times and due to this to increase the accelerated beam intensity more than by 20%

260

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.

261

Preliminary magnetic studies of lagoon and stream sediments from Chascomús Area (Argentina)—magnetic parameters as indicators of heavy metal pollution and some results of using an experimental method to separate magnetic phases  

Science.gov (United States)

Magnetic properties of lagoon and stream sediments from Chascomús area (Buenos Aires Province) and the relevance of various magnetic parameters as giving pollution status are studied in the present work. This work is focussed on magnetic parameters, such as concentration-dependent (magnetic susceptibility, saturation anhysteric and isothermal remanent magnetisation) and feature-dependent parameters (S-ratio, coercivity of remanence, anhysteric susceptibility/magnetic susceptibility-ratio), as pollution indicators. Firstly and most importantly, different magnetic parameters and chemical measurements were correlated in order to investigate their goodness, obtaining the best results for feature-dependent magnetic parameters. Coercivity of remanence correlate very well with chemical variables, showing correlations at high level of significance up to 0.9094, and the anhysteric susceptibility/magnetic susceptibility-ratio also shows very good correlations (up to 0.8376). Some results and advantages of using a new experimental method in order to discriminate hard and soft magnetic phases are also shown. This method uses alternately backfield isothermal remanent magnetisation and alternating field demagnetisation. From the experimental separation, the presence of hard magnetic phases in some samples was confirmed.

Chaparro, Marcos A. E.; Lirio, Juan M.; Nuñez, Héctor; Gogorza, Claudia S. G.; Sinito, Ana M.

2005-11-01

262

Superconductivity, metastability and magnetic field induced phase separation in the atomic limit of the Penson-Kolb-Hubbard model  

CERN Document Server

We present the analysis of paramagnetic effects of magnetic field ($B$) (Zeeman term) in the zero-bandwidth limit of the extended Hubbard model for arbitrary chemical potential $\\mu$ and electron density $n$. The effective Hamiltonian considered consists of the on-site interaction $U$ and the intersite charge exchange term $I$, determining the hopping of electron pairs between nearest-neighbour sites. The model has been analyzed within the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation (rigorous in the limit of infinite dimensions $d\\rightarrow+\\infty$). In this report we focus on metastable phases as well as phase separated (PS) states involving superconducting (SS) and nonordered (NO) phases and determine their ranges of occurrence for $U/I_0=1.05$ ($I_0=zI$) in the presence of magnetic field $B\

Kapcia, Konrad Jerzy

2014-01-01

263

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

Science.gov (United States)

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

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

2015-09-01

264

Magnetic properties of cuprate superconductors based on a phase separation theory  

Energy Technology Data Exchange (ETDEWEB)

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 La{sub 2-x}SrCuO{sub 4} (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 H{sub c2} field.

Dias, D.N. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-340 (Brazil); Caixeiro, E.S. [Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ 22290-180 (Brazil); Mello, E.V.L. de [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, RJ 24210-340 (Brazil)], E-mail: evandro@if.uff.br

2008-03-30

265

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

266

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

267

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

Science.gov (United States)

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

268

Magnetic BaFe12O19 nanofiber filter for effective separation of Fe3O4 nanoparticles and removal of arsenic  

International Nuclear Information System (INIS)

Magnetic nanoparticles are promising in applications where magnetic separation is intended, although material losses via leaching mechanisms are often inevitable. Magnetic separations with widely available permanent magnets can effectively trap particles, leading to a complete removal of used or waste particles. In this report, we first demonstrate the synthesis of the thinnest (112.7 ± 16.4 nm) and most magnetic (71.96 emu g?1) barium hexaferrite (BaFe12O19, BHF—fridge magnet) via an organic solvent-free electrospinning procedure. When the fibers are then packed into a column, they clearly remove 12 nm magnetite (Fe3O4) nanoparticles quantitatively. The same BHF cartridge also removes more than 99.9 % As-treated magnetite nanoparticles at capacities up to 70 times of its weight. As a result, one liter of 150 ?g L?1 As-contaminated water can be purified rapidly at a material cost of less than 2 US cents

269

Magnetic optical system for hf separated particle beams to the liquid hydroqen chamber ''Ludmila''  

International Nuclear Information System (INIS)

The article presents calculated and experimental characteristics of a magneto-optical system of forming and transporting beams of hf-separated particles for the 2-metre liquid hydroqen chamber ''Lyudmila'' at the Serpukhov proton accelerator. The measuring equipment and the system adjustment methods are dedescribed briefly

270

Magnetic ovalbumin and egg white aggregates as affinity adsorbents for lectins separation.  

Czech Academy of Sciences Publication Activity Database

Ro?. 40, - (2008), s. 542-545. ISSN 1369-703X R&D Projects: GA MŠk OC 157; GA MPO 2A-1TP1/094 Institutional research plan: CEZ:AV0Z60870520 Keywords : egg white * lectins * magnetic protein aggregates Subject RIV: EI - Biotechnology ; Bionics Impact factor: 1.889, year: 2008

Mad?rová, Zde?ka; Šafa?íková, Miroslava; Šafa?ík, Ivo

2008-01-01

271

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

272

Downward continuation of the Earth's geomagnetic field and separation of internal and external contribution from vector magnetic data: consistent application of the adjoint sensitivity method  

Science.gov (United States)

There are, among others, two problems related to the determination of the time dependent geomagnetic core field from satellite vector magnetic data; (a) the separation of external and internal contributions to the vector data and (b) the non-harmonic downward continuation of the geomagnetic field through an electrically conducting mantle. The measured vector components of the geomagnetic field by satellite instruments, provided by the CHAMP and SWARM missions, contain magnetic contributions of various external and internal origins. For studying the dynamics of processes in the outer core and the generated time-variable magnetic field, a separation of the core magnetic field in satellite magnetic observations is needed. Such a separation is complicated since the core magnetic field is altered by the induction and diffusion processes in the electrically conducting mantle. Especially, the effect of these processes is not negligible on the decadal and sub-decadal time scales. Based on the recently developed adjoint sensitivity method for the downward continuation of global magnetic field, we extend the theoretical formulation for a two-sided boundary-value problem by considering that the X and Z magnetic components, instead of only the internal Gauss's coefficient, is to be specified by satellite observations, and the X component of the magnetic field at the core-mantle boundary is computed. The functionality of the adjoint method is demonstrated for the geomagnetic field model CM4 by Sabaka et al. (2004), which provides time-dependent internal and external contributions to the geomagnetic field.

Hagedoorn, Jan M.; Martinec, Zdenek

2014-05-01

273

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-06-10

274

PDMAEMA-grafted core-shell-corona particles for nonviral gene delivery and magnetic cell separation.  

Science.gov (United States)

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

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

2013-09-01

275

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

International Nuclear Information System (INIS)

It is well known that photospheric flux emergence is an important process for stressing coronal fields and storing magnetic free energy, which may then be released during a flare. The Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) captured the entire emergence of NOAA AR 11158. This region emerged as two distinct bipoles, possibly connected underneath the photosphere, yet characterized by different photospheric field evolutions and fluxes. The combined active region complex produced 15 GOES C-class, two M-class, and the X2.2 Valentine's Day Flare during the four days after initial emergence on 2011 February 12. The M and X class flares are of particular interest because they are nonhomologous, involving different subregions of the active region. We use a Magnetic Charge Topology together with the Minimum Current Corona model of the coronal field to model field evolution of the complex. Combining this with observations of flare ribbons in the 1600 Å channel of the Atmospheric Imaging Assembly on board SDO, we propose a minimization algorithm for estimating the amount of reconnected flux and resulting drop in magnetic free energy during a flare. For the M6.6, M2.2, and X2.2 flares, we find a flux exchange of 4.2 × 1020 Mx, 2.0 × 1020 Mx, and 21.0 × 1020 Mx, respectively, resulting in free energy drops of 3.89 × 1030 erg, 2.62 × 1030 erg, and 1.68 × 1032 erg. and 1.68 × 1032 erg.

276

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

CERN Document Server

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

Tarr, Lucas A; Millhouse, Margaret

2013-01-01

277

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

278

Application of magnetite hexacyanoferrate composites in magnetically assisted chemical separation of cesium  

International Nuclear Information System (INIS)

Potassium nickel hexacyanoferrate composite with magnetite finds application in the recovery of cesium from low-level liquid waste using magnetic assistance. The apparent sorption capability of hexacyanoferrate-magnetite composite and potassium nickel(II) hexacyanoferrate(II) matched indicating no loss in sorption capability as a consequence of coating to nanoscale magnetite substrate. Selectivity for cesium in a broad pH range, selectivity in the presence of high concentration of sodium nitrate, and fast exchange kinetics are additional features of the nanocomposites. (author)

279

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

OpenAIRE

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

280

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

Energy Technology Data Exchange (ETDEWEB)

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

Bureau, V.

1993-12-20

281

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)

282

Phase-separated alloys for bulk exchange-biased permanent magnets  

International Nuclear Information System (INIS)

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

283

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

284

Magnetic order and charge separation in 2D distorted triangular lattice systems ?'-X[Pd(dmit)2]2  

International Nuclear Information System (INIS)

Magnetic properties of organic compounds with two-dimensional distorted triangular lattice structure, ?'-X[Pd(dmit)2]2 are investigated by the muon spin relaxation (?SR) method, where X is counter cation. We have previously reported that the X=Me4P salt (1, Me=CH3) shows a very sharp antiferromagnetic (AFM) transition at 39.3K. We have carried out ?SR measurements on other two Pd(dmit)2 salts: the X=Et2Me2P salt (2, Et=C2H5) and the Et2Me2Sb salt (3). In compound 2, an AFM transition at lower TN=15K with a smaller enhancement of the muon spin relaxation is observed, indicating a larger effect of the spin frustration than in 1. The zero-field ?SR time spectra of 3 showed an enhancement of the relaxation below ?80K, but did not show precessions. Recently, it has been suggested that this salt undergoes a phase transition to a charge-separated nonmagentic state. It is expected that the enhancement of the relaxation is related to the spin localization attributable to the charge separation

285

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

Science.gov (United States)

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

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

2015-03-31

286

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

Science.gov (United States)

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 samples were thawed at 40°C for 7 s, with fewer capacitated spermatozoa (P samples were thawed at 37°C for 30 s, 40°C for 7 s or 60°C for 6 s. Hence, we can speculate that the use of AnMACS as the sperm preparation technique can somehow enhance sperm cryosurvival rate after cryopreservation, however the fertilization potential of these cells has yet to be determined. 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

287

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

CERN Document Server

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

288

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-06-28

289

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

290

Synthesis of magnetic molecularly imprinted polymers for the selective separation and determination of metronidazole in cosmetic samples.  

Science.gov (United States)

In this study, novel magnetic molecularly imprinted polymers (MMIPs) were developed as a sorbent for solid-phase extraction (SPE) and used for the selective separation of metronidazole (MNZ) in cosmetics; MNZ was detected by high-performance liquid chromatography (HPLC). First, magnetic Fe3O4 nanoparticles (NPs) were prepared by the co-precipitation of Fe(2+)and Fe(3+) ions in an ammonia solution; then oleic acid (OA) was modified onto the surface of Fe3O4NPs. Finally, the MMIP was prepared by aqueous suspension polymerization, involving the copolymerization of Fe3O4NPs@OA with MNZ as the template molecule, methacrylic acid (MAA) as the functional monomer, ethylene glycol maleic rosinate acrylate (EGMRA) as the cross-linking agent, and 2,2-azobisisobutyronitrile (AIBN) as the initiator. The MMIP materials showed high selective adsorption capacity and fast binding kinetics for MNZ; the maximum adsorption amount of the MMIP to MNZ was 46.7 mg/g. The assay showed a linear range from 0.1 to 20.0 ?g/mL for MNZ with the correlation coefficient 0.999. The relative standard deviations (RSD) of intra- and inter-day ranging from 0.71 to 2.45 % and from 1.06 to 5.20 % were obtained. The MMIP can be applied to the enrichment and determination of MNZ in cosmetic products with the recoveries of spiked toner, powder, and cream cosmetic samples ranging from 90.6 to 104.2, 84.1 to 91.4, and 90.3 to 100.4 %, respectively, and the RSD was <3.54 %. PMID:25749799

Liu, Min; Li, Xiao-Yan; Li, Jun-Jie; Su, Xiao-Meng; Wu, Zong-Yuan; Li, Peng-Fei; Lei, Fu-Hou; Tan, Xue-Cai; Shi, Zhan-Wang

2015-05-01

291

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

Science.gov (United States)

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

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

2015-03-01

292

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

Science.gov (United States)

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

293

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

Science.gov (United States)

Poly(sodium 4-styrenesulfonate) modified magnetic nanoparticles (PSS-MNPs) were successfully synthesized and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, vibrating sample magnetometry, and Fourier-transform infrared spectrometry. The PSS-MNPs were found to enable effective separation of lysozyme from egg white. The impacts of solution pH, ionic strength, and contact time on the adsorption process were investigated. The adsorption kinetic data were well fitted using a pseudo-second-order kinetic model and the adsorption equilibrium can be reached in 3min. The adsorption isotherm data could be well described by the Langmuir equation. The maximum adsorption capacity of PSS-MNPs for lysozyme was calculated to be 476.2mgg(-1) according to the Langmuir adsorption isotherm. The fast and efficient adsorption of lysozyme by PSS-MNPs was mainly based on electrostatic interactions between them. The adsorbed lysozyme can be eluted using 20mM phosphate buffer (pH 7.0) containing 1.0M NaCl with a recovery of 96%. The extracted lysozyme from egg white demonstrated high purity, retaining about 90.7% of total lysozyme activity. PMID:25728660

Chen, Jia; Lin, Yuexin; Jia, Li

2015-04-01

294

Multifunctional inorganic-organic hybrid nanospheres for rapid and selective luminescence detection of TNT in mixed nitroaromatics via magnetic separation.  

Science.gov (United States)

Rapid, sensitive and selective detection of 2,4,6-trinitrotoluene (TNT) in aqueous solution differentiating from other nitroaromatics and independent of complicated instruments is in high demand for public safety and environmental monitoring. Despite of many methods for TNT detection, it is hard to differentiate TNT from 2,4,6-trinitrophenol (TNP) due to their highly similar structures and properties. In this work, via a simple and versatile method, LaF3?Ce(3+)-Tb(3+)and Fe3O4 nanoparticle-codoped multifunctional nanospheres were prepared through self-assembly of the building blocks. The luminescence of these nanocomposites was dramatically quenched via adding nitroaromatics into the aqueous solution. After the magnetic separation, however, the interference of other nitroaromatics including 2,4,6-trinitrophenol (TNP), 2,4-dinitrotoluene (DNT), and nitrobenzene (NB) was effectively overcome due to the removal of these coexisting nitroaromatics from the surface of nanocomposites. Due to the formation of TNT(-)-RCONH3(+), the TNT was attached to the surface of the nanocomposites and was quantitatively detected by the postexposure luminescence quenching. Meanwhile, the luminescence intensity is negatively proportional to the concentration of TNT in the range of 0.01-5.0 ?g/mL with the 3? limit of detection (LOD) of 10.2 ng/mL. Therefore, the as-developed method provides a novel strategy for rapid and selective detection of TNT in the mixture solution of nitroaromatics by postexposure luminescence quenching. PMID:24148441

Ma, Yingxin; Huang, Sheng; Wang, Leyu

2013-11-15

295

Material processing in high static magnetic field. A review of an experimental study on levitation, phase separation, convection and texturation  

OpenAIRE

An inhomogeneous magnetic field exerts a force on magnetic materials and can be used either to compensate gravity, control convection in a magnetic liquid or modify the microstructure of a solidified multiphased system where the phases exhibit dilferent magnetic susceptibilities. A homogeneous field may produce a preferred crystallographic alignment in systems which exhibit an anisotropy of their magnetic susceptibility near their melting point. We present an experimental study of those ef[ e...

Beaugnon, E.; Bourgault, D.; Braithwaite, D.; Rango, P.; Perrier La Bathie, R.; Sulpice, Andre?; Tournier, R.

1993-01-01

296

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

CERN Document Server

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

297

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

International Nuclear Information System (INIS)

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

298

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

Science.gov (United States)

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

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

2010-08-01

299

Effective separation of Am(III) and Eu(III) from HNO3 solutions using CyMe4-BTPhen-functionalized silica-coated magnetic nanoparticles.  

Science.gov (United States)

It has been shown that CyMe4-BTPhen-functionalized silica-coated maghemite (?-Fe2O3) magnetic nanoparticles (MNPs) are capable of quantitative separation of Am(III) from Eu(III) from HNO3 solutions. These MNPs also show a small but significant selectivity for Am(III) over Cm(III) with a separation factor of around 2 in 4 M HNO3. The water molecule in the cavity of the BTPhen may also play an important part in the selectivity. PMID:25331990

Afsar, Ashfaq; Harwood, Laurence M; Hudson, Michael J; Distler, Petr; John, Jan

2014-12-11

300

A Quantitative Determination of Magnetic Nanoparticle Separation Using On-Off Field Operation of Quadrupole Magnetic Field-Flow Fractionation (QMgFFF)  

OpenAIRE

Quadrupole Magnetic Field-Flow Fractionation (QMgFFF) is a technique for characterization of sub-micrometer magnetic particles based on their retention in the magnetic field from flowing suspensions. Different magnetic field strengths and volumetric flow rates were tested using on-off field application and two commercial nanoparticle preparations that significantly differed in their retention parameter, ? (by nearly 8-fold). The fractograms showed a regular pattern of highe...

Orita, Toru; Moore, Lee R.; Joshi, Powrnima; Tomita, Masahiro; Horiuchi, Takashi; Zborowski, Maciej

2013-01-01

301

Low-frequency resistance fluctuations in a single nanowire (diameter ? 45 nm) of a complex oxide and its relation to magnetic transitions and phase separation  

Science.gov (United States)

We report measurement of low frequency resistance noise spectroscopy in a single strand of a nanowire (NW) (diameter ? 45 nm) of a complex oxide manganite La0.5Sr0.5MnO3, that showed ferromagnetic transition (TC ? 315 K), an antiferromagnetic transition (TN ? 210 K) and a phase-separated region below TN. We demonstrated that noise spectroscopy in a single NW can cleanly detect the magnetic transitions including the phase-coexistence that may not be possible to do by magnetic measurements. The normalized noise in the single NW is an order less than that reported in ultralow-noise Si Junction Field Effect Transistor.

Datta, Subarna; Samanta, Sudeshna; Ghosh, Barnali; Raychaudhuri, A. K.

2014-08-01

302

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

303

Recovery of very fine and ultra fine uraninite particles using superconducting high gradient magnetic separator: a case study with copper plant tailings  

International Nuclear Information System (INIS)

Experimental studies were carried out on superconducting high gradient magnetic separator (SC-HGMS), designed and developed in BARC, on a low grade (assaying 3O8) uranium ore feed prepared from Rakha copper plant tailings in which uranium occurs as uraninite. The earlier studies carried out on wet high intensity magnetic separator (WHIMS) showed that the uraninite recovery reduces when the particle size decreases below 20?m and it does not exceed 20% for particles below 5 ?m. The present studies show that the SC-HGMS is able to recover efficiently very fine and ultrafine uraninite particles and, the recovery is more than 60% particles even below 5 ?m. It is thus possible to achieve significant improvement in the overall uraninite recovery by use of WHIMS in tandem with SC-HGMS. (author). 5 refs., 1 fig., 1 tab

304

Anomalous phase separation in La0.225Pr0.4Ca0.375MnO3: consequence of temperature and magnetic-field cycles  

International Nuclear Information System (INIS)

The evolutions of electronic phase separation in manganites La0.225Pr0.4Ca0.375MnO3 are studied by the specific temperature and magnetic-field cycling experiments. It is found that the electronic phase separation state at low temperature can be tuned substantially by temperature and/or magnetic-field cycles. Surprisingly, the initial more ferromagnetic metallic (FMM) nuclei can impede the growth of these nuclei during the cooling process. It implies that there must coexist more than two phases which take part in the complex first-order phase transitions, and the charge-disordered insulating phase is possible, one of the parent phases transiting into the FMM phase at low temperature. In addition, the accommodation strain is suggested to control the nucleation and growth of FMM domains. (orig.)

305

Possibility of generating radioactive beams by means of cyclotron and a magnetic separator for an inverse-kinematics study of resonance elastic scattering  

International Nuclear Information System (INIS)

The possibility of combining a cyclotron with a magnetic separator to generate radioactive beams of light nuclei is discussed. The possible use of such beams to study resonance elastic scattering is also discussed. The sources of the radioactive beams are inverse-kinematics (p,n) reactions. The yields of (p,n) reactions are analyzed. The factors which determine the cross sections for these reactions in the resonance region are examined. 20 refs., 8 figs., 2 tabs

306

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

Science.gov (United States)

Magnetic in-situ quenching refers to fixing and quenching the sample at a static high magnetic field (SHMF) up to 18 T; it has been achieved by a specially designed facility. Zn-7wt%Bi and Zn-10wt%Bi hyper-monotectic melts were quenched under different magnetic flux densities to investigate the influence of SHMF on the liquid-liquid phase separation process in solidifying hyper-monotectic alloys. Because this separation is mainly caused by the growth of minority phase droplets (Bi droplets in the present study), and such growth is attributed to the diffusion of Bi element and the coalescence between the droplets, the influence of SHMF on the growth of Bi droplets was analyzed. Results show that the imposed SHMF prevented the formation of layered structure in the Zn-10wt%Bi alloy and refined the Bi particles in the Zn-7wt%Bi alloy, which indicates that the SHMF retarded the liquid-liquid phase separation during solidifying the hyper-monotectic alloys. Indeed, the two motions of droplets in determining the coalescence, Marangoni migration and Stocks sedimentation, were slowed down by the applied SHMF. Analytical estimations of the magnitude of such damping effect have been made and show that the 18 T SHMF could reduce the speed of Stokes sedimentation and Marangoni migration of the minority phase droplets by about 95.5 % and 62.4 %, respectively.

Wang, J.; Zhong, Y. B.; Fautrelle, Y.; Zheng, T. X.; Li, F.; Ren, Z. M.; Debray, F.

2013-09-01

307

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)

308

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

309

Recent advances in the application of core-shell structured magnetic materials for the separation and enrichment of proteins and peptides.  

Science.gov (United States)

Many endogenous proteins/peptides and proteins/peptides with post-translational modifications (PTMs) are presented at extremely low abundance, and they usually suffer strong interference with highly abundant proteins/peptides as well as other contaminants, resulting in low ionization efficiency in MS analysis. Therefore, the separation and enrichment of proteins/peptides from complex mixtures is of great importance to the successful identification of them. Core-shell structured magnetic microspheres have been widely used in the enrichment and isolation of proteins/peptides, thanks to unique properties such as strong magnetic responsiveness, outstanding binding capacity, excellent biocompatibility, robust mechanical strength and admirable recoverability. The aim of this review is to update the advances in the application of core-shell structured magnetic materials for proteomics analysis, including the separation and enrichment of low-concentration proteins/peptides, the selective enrichment of phosphoproteins and the selective enrichment of glycoproteins, and to compare the enrichment performance of magnetic microspheres with different kinds of functionalization. PMID:24835765

Zhao, Man; Xie, Yiqin; Deng, Chunhui; Zhang, Xiangmin

2014-08-29

310

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

311

Phase separation, effects of magnetic field and high pressure on charge ordering in ?-Na0.5CoO2  

International Nuclear Information System (INIS)

Transmission electron microscopy (TEM) observations reveal the presence of complex superstructures and remarkable phase separation in association with Na-ordering phenomenon in ?-Na0.5CoO2. Resistivity and magnetization measurements indicate that three phase transitions at the temperatures of 25, 53 and 90 K, respectively, appear commonly in ?-Na0.5CoO2 samples. Under a high pressure up to 10 kbar, the low-temperature transport properties show certain changes below the charge order transition; under an applied magnetic field of 7 T, phase transitions at around 25 and 53 K, proposed fundamentally in connection with alternations of magnetic structure and charge ordering maintain almost unchanged

312

Simple synthesis of functionalized superparamagnetic magnetite/silica core/shell nanoparticles and their application as magnetically separable high-performance biocatalysts  

Energy Technology Data Exchange (ETDEWEB)

We report on the facile large-scale synthesis of magnetite@silica core-shell nanoparticles by a simple addition of tetraethyl orthosilicate (TEOS) into reverse micelles during the formation of uniformly-sized magnetite nanoparticles. The size of magnetic core was determined by the ratio of solvent and surfactant in reverse micelle solution while the thickness of silica shell could be easily controlled by adjusting the amount of added TEOS. Amino group functional groups were grafted to the magnetic nanoparticles, and crosslinked enzyme clusters (CEC) were fabricated on the surface of magnetite@silica nanoparticles. The resulting hybrid materials of magnetite and CEC were magnetically separable, highly active, and stable enough to show no decrease of enzyme activity under rigorous shaking for more than 15 days.

Lee, Jinwoo; Lee, Youjin; Youn, Jongkyu; Na, Hyon Bin; Yu, Taekyung; Kim, Hwan O.; Lee, Sang-mok; Koo, Yoon-mo; Kwak, Ja Hun; Park, Hyun-Gyu; Chang, Ho Nam; Hwang, Misun; Park, Je-Geun; Kim, Jungbae; Hyeon, Taeghwan

2008-01-01

313

Synthesis of a thin-layer MnO? nanosheet-coated Fe?O? 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

314

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

International Nuclear Information System (INIS)

Graphical abstract: An effective route has been developed to synthesize magnetic Fe3O4@SiO2@TiO2-Ag microspheres with well-defined core–shell nanostructure and enhanced photocatalytic activity. -- Highlights: • Controllable synthesis of core–shell structured Fe3O4@SiO2@TiO2-Ag magnetic nanocomposite. • The unique nanostructure of Fe3O4@SiO2@TiO2-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 Fe3O4@SiO2@TiO2-Ag nanocomposite has been synthesized and characterized by a series of techniques including SEM, TEM, XRD, XPS as well as magnetization measurement and subsequently tested for the photocatalytic activities. The well-designed nanocomposite exhibits significantly superior activity to that of the commercial Degussa P25 thanks to the suppression of electron–hole pairs from recombination by Ag nanoparticles, and can be easily recycled by applying an external magnetic field while maintaining the catalytic activity without significant decrease even after running 10 times. The unique nanostructure makes Fe3O4@SiO2@TiO2-Ag a highly efficient, recoverable, stable, and cost-effective photocatalytic system offering broad opportunities in the field of catalyst synthesis and application

315

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.

316

Bifunctional magnetic nanobeads for sensitive detection of avian influenza A (H7N9) virus based on immunomagnetic separation and enzyme-induced metallization.  

Science.gov (United States)

Bifunctional magnetic nanobeads (bi-MBs) were fabricated by co-immobilizing target recognition molecules and signal molecules on a magnetic nanobead surface, which were used as both separation and enrichment carriers and signal carriers. The bi-MBs could capture and separate avian influenza A (H7N9) virus (H7N9 AIV) from complex samples efficiently based on the specific reaction between antigen-antibody and their good magnetic response, which simplified sample pretreatment and saved the detection time. Taking advantages of their high surface to volume ratio and rich surface functional groups, multiple alkaline phosphatase (ALP) signal molecules were tethered on the surface of bi-MBs which greatly amplified the detection signal. As an efficient signal amplification strategy, enzyme-induced metallization had been integrated with bi-MBs and anodic stripping voltammetry to construct an ultrasensitive electrochemical immunosensor for H7N9 AIV detection. Under the optimal conditions, the introduction of bi-MBs could amplify the detection signal in about four times compared with the same immunoassay without MBs, and the method showed a wide linear range of 0.01-20 ng/mL with a detection limit of 6.8 pg/mL. The electrochemical immunosensor provides a simple and reliable platform with high sensitivity and selectivity which shows great potential in early diagnosis of diseases. PMID:25643598

Wu, Zhen; Zhou, Chuan-Hua; Chen, Jian-Jun; Xiong, Chaochao; Chen, Ze; Pang, Dai-Wen; Zhang, Zhi-Ling

2015-06-15

317

Yolk-shell nanostructured Fe3O4@NiSiO3 for selective affinity and magnetic separation of His-tagged proteins.  

Science.gov (United States)

Recent developments of nanotechnology encourage novel materials for facile separations and purifications of recombinant proteins, which are of great importance in disease diagnoses and treatments. We find that Fe3O4@NiSiO3 with yolk-shell nanostructure can be used to specifically purify histidine-tagged (His-tagged) proteins from mixtures of lysed cells with a recyclable process. Each individual nanoparticle composes by a mesoporous nickel silicate shell and a magnetic Fe3O4 core in the hollow inner, which is featured by its great loading efficiency and rapid response toward magnetic fields. The abundant Ni(2+) cations on the shell provide docking sites for selective coordination of histidine and the reversible release is induced by excess imidazole solution. Because of the Fe3O4 cores, the separation, concentration, and recycling of the nanocomposites become feasible under the controls of magnets. These characteristics would be highly beneficial in nanoparticle-based biomedical applications for targeted-drug delivery and biosensors. PMID:25303145

Wang, Yang; Wang, Guangchuan; Xiao, Yun; Yang, Yuling; Tang, Ruikang

2014-11-12

318

A novel magnetically separable TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber with high photocatalytic activity under UV-vis light  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: A novel magnetically separable composite photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technique, which can be reclaimed with a magnet, and the decolorizing efficiency of MB solution reached 95.87%. Highlights: Black-Right-Pointing-Pointer The composite TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers with diameter of 110 {+-} 28 nm have been successfully synthesized by the combination of sol-gel method and electrospinning technique. Black-Right-Pointing-Pointer The presence of Co{sup 2+} or/and Fe{sup 3+} ions may occupy some of the lattice sites of TiO{sub 2} to form an iron-titanium solid solution and narrow the band gap, which broadens the response region of visible light. Black-Right-Pointing-Pointer The resultant nanofibers not only have high decomposition efficiency with methylene blue (MB) under the UV irradiation, which is close to that of Degussa P25, but also can be separated with a magnet and avoid the secondary pollution of the treated water. -- Abstract: A novel magnetically separable heterogeneous photocatalyst TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofiber was prepared by sol-gel method and electrospinning technology, followed by heat treatment at 550 Degree-Sign C for 2 h. The phase structure, morphology and magnetic property of the composite nanofibers were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and vibrating sample magnetometer analysis. The photocatalytic studies of TiO{sub 2}/CoFe{sub 2}O{sub 4} fibers suggested that the presence of CoFe{sub 2}O{sub 4} not only enhanced the absorbance of UV light, but also broadened the response region to visible light. The decolorizing efficiency of methylene blue (MB) solution reaches 95.87% over TiO{sub 2}/CoFe{sub 2}O{sub 4} nanofibers under 300 W Hg lamp after 5 h, which is close to that of Degussa P25. Furthermore, these fibers can be collected with a magnet for reuse and effectively avoid the secondary pollution of the treated water.

Li, Cong-Ju, E-mail: congjuli@gmail.com [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China); Wang, Jiao-Na; Wang, Bin [Beijing Key Laboratory of Clothing Materials R and D and Assessment, Beijing Institute of Fashion Technology, Beijing 100029 (China); Gong, Jian Ru, E-mail: gongjr@nanoctr.cn [National Center for Nanoscience and Technology, China, 11 Zhongguancun Beiyitiao, Beijing 100190 (China); Lin, Zhang [Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fujian 350002 (China)

2012-02-15

319

A novel magnetically separable TiO2/CoFe2O4 nanofiber with high photocatalytic activity under UV–vis light  

International Nuclear Information System (INIS)

Graphical abstract: A novel magnetically separable composite photocatalyst TiO2/CoFe2O4 nanofiber was prepared by sol–gel method and electrospinning technique, which can be reclaimed with a magnet, and the decolorizing efficiency of MB solution reached 95.87%. Highlights: ? The composite TiO2/CoFe2O4 nanofibers with diameter of 110 ± 28 nm have been successfully synthesized by the combination of sol–gel method and electrospinning technique. ? The presence of Co2+ or/and Fe3+ ions may occupy some of the lattice sites of TiO2 to form an iron–titanium solid solution and narrow the band gap, which broadens the response region of visible light. ? The resultant nanofibers not only have high decomposition efficiency with methylene blue (MB) under the UV irradiation, which is close to that of Degussa P25, but also can be separated with a magnet and avoid the secondary pollution of the treated water. -- Abstract: A novel magnetically separable heterogeneous photocatalyst TiO2/CoFe2O4 nanofiber was prepared by sol–gel method and electrospinning technology, followed by heat treatment at 550 °C for 2 h. The phase structure, morphology and magnetic property of the composite nanofibers were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope and vibrating sample magnetometer analysis. The photocatalytic studies of TiO2/CoFe2O4 fibers suggested that the presence of CoFe2O4 not only enhanced the absorbance of UV light, but also broadened the response region to visible light. The decolorizing efficiency of methylene blue (MB) solution reaches 95.87% over TiO2/CoFe2O4 nanofibers under 300 W Hg lamp after 5 h, which is close to that of Degussa P25. Furthermore, these fibers can be collected with a magnet for reuse and effectively avoid the secondary pollution of the treated water.

320

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

321

Magnetic composite of Fe3O4 and activated carbon as a adsorbent for separation of trace Sr(II) from radioactive wastewater  

International Nuclear Information System (INIS)

Magnetic adsorbent of Fe3O4 and activated carbon (Fe3O4/AC) was prepared by chemical coprecipitation technique, and was characterized by SEM, TEM, BET, XRD, and VSM techniques in details. The adsorption results of Sr(II) on Fe3O4/AC revealed that Sr(II) adsorption on Fe3O4/AC surface was an spontaneous and endothermic process, and can be well described by the pseudo-second-order model. The adsorption of Sr(II) on Fe3O4/AC increased with increasing pH, and decreased with increasing ionic strength. Fe3O4/AC can be easily separated from aqueous solution with an external magnetic field after application. (author)

322

Volume reduction on all particle size of the contaminated soil. Continuous processing technology of attrition, chemical wash under an ambient temperature and pressure condition and magnetic separation  

International Nuclear Information System (INIS)

An examination was conducted in order to establish a practical purification system that could largely reduce the storage volume of radioactive waste in the Intermediate Storage Facility. The examination consists of a 3-step washing treatment of contaminated soil, which includes “Milling Washing” of removed contaminated soil, chemical extraction of fine soil fraction resulted from the “Milling Washing” under an ambient temperature and pressure condition, and magnetic separation of cesium from the extracted solution. As a result of the examination, we succeeded in development of a safe system with low initial cost and running cost. (author)

323

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

324

Separate Colors, Separate Minds.  

Science.gov (United States)

Explains that racial separation causes cultural separation, and the way to improve race relations is to continue to move toward integration. Discusses the need to debunk race, examining racial issues in education. Highlights the importance of actively supporting integration and opposing separatism, explaining that for there to be social progress,…

Meyers, Michael; Nidiry, John P.

2002-01-01

325

Strain-induced oxygen defect formation and interfacial magnetic phase separation in SrTiO3(001)/La1-xSrxCoO3  

Science.gov (United States)

The remarkable functionality and epitaxial compatibility of complex oxides provides many opportunities for new physics and applications in oxide heterostructures. Perovskite manganites and cobaltites provide excellent examples, being of interest for solid oxide fuel cells, catalysis, ferroelectric RAM, gas sensing, resistive switching memory, and oxide spintronics. However, the same delicate balance between phases that provides this diverse functionality also leads to a serious problem - the difficulty of maintaining desired properties close to the interface with other oxides. Although this problem is widespread, manifests itself in several ways, and could present a significant roadblock to the development of heterostructured devices for oxide electronics, there is no consensus as to its origin, or even whether it is driven by electronic or chemical effects. In this work, using SrTiO3(001)/La1-xSrxCoO3 as a model system, we have combined epitaxial growth via high pressure oxygen sputtering with high resolution x-ray diffraction, atomic resolution electron microscopy and spectroscopy, and detailed magnetic, transport, and neutron scattering measurements to determine the fundamental origin of the deterioration in interfacial transport and magnetism. The effect is found to be due to nanoscopic magnetic phase separation in the near-interface region driven by a significant depletion in interfacial hole doping due to accumulation of O vacancies. This occurs due to a novel mechanism for accommodation of lattice mismatch with the substrate based on formation and long-range ordering of O vacancies, thus providing a fundamental link between strain state and O vacancy density. Further impacts of the O vacancy ordering and interfacial magnetic phase separation, such as formation of a spin-state superlattice and an extraordinary coercivity enhancement, will also be discussed. Work in collaboration with M. Sharma, M. Torija, J. Schmitt, C. He, S. El-Khatib, J. Gazquez, M. Varela, M. Laver and J. Borchers.

Leighton, Chris

2012-02-01

326

Magnetically assisted chemical separation (MACS): a promising technique for the uptake of actinides, lanthanides and fission products from nuclear wastes  

International Nuclear Information System (INIS)

The present work deals with the development of MACS process for the uptake of various actinides, lanthanides and fission products from nitric acid solutions using tiny magnetic particles (cross-linked polyacrylamide and acrylic acid entrapping charcoal and iron oxide, 1:1:1, particle size 1-60 ?m) coated with N,N'-dimenthyl N,N'-dubutyl tetradecyl melonamide (DMDBTDMA)

327

Magnetic ordering in electronically phase-separated La2-xSrxCuO4+y: Neutron diffraction experiments  

DEFF Research Database (Denmark)

We present results of magnetic neutron diffraction experiments on the codoped superoxygenated La2-xSrxCuO4+y (LSCO+O) system with x=0.09. We find that the magnetic phase is long-range ordered incommensurate antiferromagnetic with a Neacuteel temperature T-N coinciding with the superconducting ordering temperature T-c=40 K. The incommensurability value is consistent with a hole doping of n(h)approximate to 1>8 but in contrast to nonsuperoxygenated La2-xSrxCuO4 with hole doping close to n(h)approximate to 18 the magnetic-order parameter is not field dependent. We attribute this to the magnetic order being fully developed in LSCO+O as in the spin and charge ordered "stripe" compounds La1.48Nd0.40Sr0.12CuO4 and La7/8Ba1/8CuO4.

Udby, Linda; Andersen, Niels Hessel

2009-01-01

328

Magnetically-Separable and Highly-Stable Enzyme System Based on Crosslinked Enzyme Aggregates Shipped in Magnetite-Coated Mesoporous Silica  

Energy Technology Data Exchange (ETDEWEB)

Magnetically-separable and highly-stable enzyme system was developed by adsorption of enzymes in superparamagnetic hierarchically ordered mesocellular mesoporous silica (M-HMMS) and subsequent enzyme crosslinking. Superparamagnetic nanoparticles were homogeneously incorporated into hierarchically-ordered mesocellular mesoporous silica (HMMS) by the decomposition of preformed iron propionate complex. The size of incorporated superparamagnetic 15 nanoparticles was around 5 nm, generating a magnetically separable host with high pore volumes and large pores (M-HMMS). ?-chymotrypsin (CT) was adsorbed into M-HMMS with high loading (~30 wt%) in less than 30 minutes. Glutaraldehyde (GA) treatment of adsorbed CT resulted in nanometer scale crosslinked enzyme aggregates in M-HMMS (CLEA-M). The activity of these CT aggregates in M-HMMS (CLEA-M-CT) was 34 times than that of simply adsorbed CT in M20 HMMS, due to an effective prevention of enzyme leaching during washing via a ship-in-a-bottle approach. CLEA-M-CT maintained the intial activity not only under shaking (250 rpm) for 30 days, but also under recycled uses of 35 times. The same approach was employed for the synthesis of CLEA-M of lipase (CLEA-M-LP), and proven to be effective in improving the loading, activity, and stability of enzyme when compared to those of adsorbed LP in M-HMMS.

Lee, Jinwoo; Na, Hyon Bin; Kim, Byoung Chan; Lee, Jin Hyung; Lee, Byoungsoo; Kwak, Ja Hun; Hwang, Yosun; Park, Je-Geun; Gu, Man Bock; Kim, Jaeyun; Joo, Jin; Shin, Chae-Ho; Grate, Jay W.; Hyeon, Taeghwan; Kim, Jungbae

2009-10-15

329

Enantiomeric separation by microchip electrophoresis using bovine serum albumin conjugated magnetic core-shell Fe3 O4 @Au nanocomposites as stationary phase.  

Science.gov (United States)

In this work, a novel enantioselective MCE was developed employing BSA-conjugated Fe3 O4 @Au nanoparticles (Fe3 O4 @Au NPs) as stationary phase. Fe3 O4 @Au NPs with high magnetic responsively, excellent solubility, and high dispersibility in water were prepared through a sonochemical synthesis strategy. BSA was then immobilized onto the Fe3 O4 @Au NPs surfaces through the well-developed interaction between Au NPs and amine groups of BSA to form Fe3 O4 @Au NPs-BSA conjugates, which were then locally packed into PDMS microchannels with the help of magnets. The resultant Fe3 O4 @Au NPs-BSA conjugates not only have the magnetism of Fe3 O4 NPs that make them easily manipulated by an external magnetic field, but also have the larger surface and excellent biocompatibility of Au shell, which can incorporate much more biomolecules and well maintain their biological activity. In addition, the successful BSA decorations endowed Fe3 O4 @Au NPs-BSA conjugates with pH-tunable water solubility related to the pI of BSA (pI 4.7) and led to enhanced stability against high ionic strength. Compared with the native PDMS microchannel, the modified surfaces exhibited more stable and suppressed electroosmotic mobility, and less nonspecific adsorption toward analytes. Successful separation of chiral amino acids (tryptophan and threonine) and ofloxacin enantiomers demonstrate that the constructed MCE columns own ideal enantioselectivity. The results are expected to open up a new possibility for high-throughput screening of enantiomers with protein targets as well as a new application of magnetic NPs. PMID:25042461

Liang, Ru-Ping; Wang, Xiao-Ni; Wang, Li; Qiu, Jian-Ding

2014-10-01

330

Metastable bound state of a pair of two-dimensional spatially separated electrons in anti-parallel magnetic fields  

CERN Document Server

We propose a new mechanism for binding of two equally charged carriers in a double-layer system subjected by a magnetic field of a special form. A field configuration for which the magnetic fields in adjacent layers are equal in magnitude and opposite in direction is considered. In such a field an additional integral of motion - the momentum of the pair P arises. For the case when in one layer the carrier is in the zero (n=0) Landau level while in the other layer - in the first (n=1) Landau level the dependence of the energy of the pair on its momentum E(P} is found. This dependence turns out to be nonmonotonic one : a local maximum and a local minimum appears, indicating the emergence of a metastable bound state of two carrier with the same sign of electrical charge.

Shevchenko, S I

2003-01-01

331

The use of magnetic poly(N-isopropylacrylamide) microspheres for separation of DNA from probiotic dairy products.  

Czech Academy of Sciences Publication Activity Database

Ro?. 1, ?. 2 (2012), s. 235-240. ISSN 2164-9634 R&D Projects: GA AV ?R(CZ) KAN401220801; GA MŠk 2B06053; GA MŠk 7E12054 Grant ostatní: European Commission(XE) FP-7 DiaTools No. 259796 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : magnetic particles * thermosensitive * poly(N-isopropylacrylamide) Subject RIV: EE - Microbiology, Virology

Macková, Hana; Horák, Daniel; Trachtová, Š.; Rittich, B.; Španová, A.

2012-01-01

332

Application of spin-orbit-coupling induced magnetic field effects for probing the dynamics of photoinduced charge separation and recombination  

OpenAIRE

In this paper we present two examples demonstrating how magnetic field effects can be utilized for a quantitative exploration of mechanistic details of the behaviour of short-lived redox intermediates in photoelectron transfer reactions with excited triplet states. This magnetokinetic approach takes advantage of the spin memory present in the intermediates (exciplexes, correlated radical pairs) which controls the competition between spin-allowed formation of free redox products and spin-forbi...

Steiner, Ulrich; Haas, Werner; Wolff, Hans-joachim; Bu?rßner, Dieter

1992-01-01

333

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

334

Recovery of metals from Cuban nickel tailings by leaching with organic acids followed by precipitation and magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

The percolation leaching of the Cuban nickel tailings containing 0.34% Ni, 0.08% Co and 44.2% Fe was investigated by using tartaric and oxalic acids at different concentrations. About 70% Ni, 80% Co and 30% Fe were extracted after 5 days of leaching with the mixture of 0.15 mol/L tartaric acid and 0.05 mol/L oxalic acid at ambient temperature and normal pressure. Nickel and cobalt extraction of 80% as well as iron extraction of 50% were achieved from the pregnant solution by means of precipitation at 80 deg. C for 2 h. The precipitation at ambient temperature led to a similar result after 16 days. Cobalt, nickel and iron oxalates were found in the precipitate by using the X-ray diffraction method. The regeneration of acids during the precipitation step made possible the reuse of the raffinate at the leaching step. Heating of the precipitate at 200 deg. C increased the metal concentration to 1.22% Ni and 0.33% Co, which can be fed in the existing nickel plant in Moa, Cuba. The magnetic processing of the leaching residues led to a non-magnetic product containing less than 20% Fe and a magnetic product containing more than 50% Fe.

Hernandez, C.M.F. [High Institute of Mining and Metallurgy ' Dr. Antonio Nunez Jimenez' , Moa (Cuba); Banza, A.N. [Institute of Mineral Processing and Waste Disposal, Clausthal University of Technology, Walther-Nernst-Strasse 9, Clausthal-Zellerfeld (Germany)]. E-mail: anbanza@yahoo.com; Gock, E. [Institute of Mineral Processing and Waste Disposal, Clausthal University of Technology, Walther-Nernst-Strasse 9, Clausthal-Zellerfeld (Germany)

2007-01-02

335

Recovery of metals from Cuban nickel tailings by leaching with organic acids followed by precipitation and magnetic separation.  

Science.gov (United States)

The percolation leaching of the Cuban nickel tailings containing 0.34% Ni, 0.08% Co and 44.2% Fe was investigated by using tartaric and oxalic acids at different concentrations. About 70% Ni, 80% Co and 30% Fe were extracted after 5 days of leaching with the mixture of 0.15 mol/L tartaric acid and 0.05 mol/L oxalic acid at ambient temperature and normal pressure. Nickel and cobalt extraction of 80% as well as iron extraction of 50% were achieved from the pregnant solution by means of precipitation at 80 degrees C for 2h. The precipitation at ambient temperature led to a similar result after 16 days. Cobalt, nickel and iron oxalates were found in the precipitate by using the X-ray diffraction method. The regeneration of acids during the precipitation step made possible the reuse of the raffinate at the leaching step. Heating of the precipitate at 200 degrees C increased the metal concentration to 1.22% Ni and 0.33% Co, which can be fed in the existing nickel plant in Moa, Cuba. The magnetic processing of the leaching residues led to a non-magnetic product containing less than 20% Fe and a magnetic product containing more than 50% Fe. PMID:17084523

Hernández, C M F; Banza, A N; Gock, E

2007-01-01

336

Recovery of metals from Cuban nickel tailings by leaching with organic acids followed by precipitation and magnetic separation  

International Nuclear Information System (INIS)

The percolation leaching of the Cuban nickel tailings containing 0.34% Ni, 0.08% Co and 44.2% Fe was investigated by using tartaric and oxalic acids at different concentrations. About 70% Ni, 80% Co and 30% Fe were extracted after 5 days of leaching with the mixture of 0.15 mol/L tartaric acid and 0.05 mol/L oxalic acid at ambient temperature and normal pressure. Nickel and cobalt extraction of 80% as well as iron extraction of 50% were achieved from the pregnant solution by means of precipitation at 80 deg. C for 2 h. The precipitation at ambient temperature led to a similar result after 16 days. Cobalt, nickel and iron oxalates were found in the precipitate by using the X-ray diffraction method. The regeneration of acids during the precipitation step made possible the reuse of the raffinate at the leaching step. Heating of the precipitate at 200 deg. C increased the metal concentration to 1.22% Ni and 0.33% Co, which can be fed in the existing nickel plant in Moa, Cuba. The magnetic processing of the leaching residues led to a non-magnetic product containing less than 20% Fe and a magnetic product containing more than 50% Fe

337

Solid-solid grinding/templating route to magnetically separable nitrogen-doped mesoporous carbon for the removal of Cu(2+) ions.  

Science.gov (United States)

N-doped ordered mesoporous carbon materials (NOMC) with 2D hexagonal symmetry structure were synthesized via a facile solid-solid grinding/templating route, in which the ionic liquids (ILs) of 1-cyanoethyl-3-methylimidazolium chloride and SBA-15 were employed as the precursor and hard template, respectively. The as-synthesized NOMC features with a uniform mesoporous size (3.5nm), ropes-like morphology (0.4-1?m in length) and high surface area (803m(2)/g). The quantitative analysis revealed the nitrogen content on the surface of NOMC is 5.5at%. Magnetic iron nanoparticles were successfully embedded into the carbon matrix by introducing iron chloride to the mixture of SBA-15 and ILs during the synthesis process. The NOMC-Fe composite possessed superior adsorption capacity of Cu(2+) ions (23.6mg/g). Kinetic and isothermal analysis demonstrated the strong interactions between Cu(2+) ion and the adsorbent. Furthermore, the composite was magnetically separable from solution under an external magnetic field and thus displayed a superior reusability in the recycling test. PMID:25072134

Chen, Aibing; Yu, Yifeng; Zhang, Yue; Xing, Tingting; Wang, Yanyan; Zhang, Yexin; Zhang, Jian

2014-08-30

338

Quantitative estimation of left ventricular ejection fraction from mitral valve E-point to septal separation and comparison to magnetic resonance imaging.  

Science.gov (United States)

This study tested the hypothesis that the mitral valve E point-to-septal separation (EPSS) can be used to quantify the left ventricular (LV) ejection fraction (EF) on a continuous scale rather than simply as "normal" or "reduced." After excluding 5 patients with mitral valve prostheses, asymmetric septal hypertrophy, or significant aortic insufficiency, EPSS was measured in 42 patients by 3 independent observers on a cardiac magnetic resonance image identical to the echocardiographic parasternal long-axis view. In each patient, the reference standard LVEF was calculated from the magnetic resonance short-axis cross-sectional stack images by Simpson's rule and ranged from 11% to 72%. For all 42 patients, linear regression revealed the relation magnetic resonance imaging (MRI) LVEF = 75.5 - 2.5. EPSS (millimeters). Correlation between EPSS and the MRI LVEF for the 3 observers agreed closely, ranging from r = 0.78 to r = 0.82 (SEE 9 to 10), with similar regression coefficients. After blinded segmental wall motion scoring of the gated magnetic resonance cine images of the left ventricle in each patient, correlations, SEEs, and regression coefficients were found to be very similar in the 21 patients with the most homogenous wall motion, compared with the 21 patients with the most heterogenous wall motion. In conclusion, clinically useful quantitative prediction of the LVEF as a continuous variable can be obtained from the EPSS with a simple linear regression equation in a substantial portion of patients and may be a useful adjunct for assessment of LV function. PMID:16377299

Silverstein, Jay R; Laffely, Nicholas H; Rifkin, Robert D

2006-01-01

339

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

International Nuclear Information System (INIS)

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

340

Separation and extraction of Co(II) using magnetic chitosan nanoparticles grafted with ?-cyclodextrin and determination by FAAS  

Science.gov (United States)

A novel and selective method for the fast determination of trace amounts of Co(II) ions in water samples has been developed. The procedure is based on the selective sorption of Co(II) ions using magnetic chitosan nanoparticles grafted with ?-cyclodextrin at different pH followed by elution with organic eluents and determination by atomic absorption spectrometry The preconcentration factor was 100 (1 mL elution volume) for a 100 mL sample volume. The limit of detection of the proposed method is 1.0 ng mL-1. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of Co per gram of sorbent. The relative standard deviation under optimum conditions was 3.0% ( n = 10). Accuracy and applicability of the method was estimated using test samples of natural and model water with different amounts of Co(II).

Moghimi, Ali

2014-12-01

341

Quantum dynamics of charged and neutral magnetic solitons Spin-charge separation in the one-dimensional Hubbard model  

CERN Document Server

We demonstrate that the Configuration Interaction (CI) Approximation recaptures essential features of the exact (Bethe Ansatz) solution to the 1D Hubbard model. As such, it provides valuable route for describing effects which go beyond mean-field theory for strongly correlated electron systems in higher dimensions. The CI method systematically describes fluctuation and quantum tunneling corrections to the Hartree-Fock Approximation (HFA). HFA predicts that doping a half-filled Hubbard chain leads to the appearance of charged spin-polarons or charged domain-wall solitons in the antiferromagnetic (AFM) background. The CI method, on the other hand, describes the quantum dynamics of these charged magnetic solitons and quantum tunneling effects between various mean-field configurations. In this paper, we test the accuracy of the CI method against the exact solution of the one-dimensional Hubbard model. We find remarkable agreement between the energy of the mobile charged bosonic domain-wall (as given by the CI met...

Berciu, M; Berciu, Mona; John, Sajeev

1999-01-01

342

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

DEFF Research Database (Denmark)

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

Olsen, Stig Irving; Bonou, Alexandra

2012-01-01

343

Magnetism  

Science.gov (United States)

This webpage is part of the University Corporation for Atmospheric Research (UCAR) Windows to the Universe program. It describes the nature and configuration of magnetic fields, which are the result of moving electric charges, including how they cause magnetic objects to orient themselves along the direction of the magnetic force points, which are illustrated as lines. Magnetic field lines by convention point outwards at the north magnetic pole and inward at the south magnetic pole. The site features text, scientific illustrations and an animation. Text and vocabulary are selectable for the beginning, intermediate, or advanced reader.

University Corporation for Atmospheric Research Windows to the Universe team

2007-12-12

344

On separable Pauli equations  

OpenAIRE

We classify (1+3)-dimensional Pauli equations for a spin-1/2 particle interacting with the electro-magnetic field, that are solvable by the method of separation of variables. As a result, we obtain the eleven classes of vector-potentials of the electro-magnetic field A(t,x) providing separability of the corresponding Pauli equations. It is established, in particular, that the necessary condition for the Pauli equation to be separable into second-order matrix ordinary differe...

Zhalij, Alexander

2002-01-01

345

Magnetic order and charge separation in 2D distorted triangular lattice systems {beta}{sup '}-X[Pd(dmit){sub 2}]{sub 2}  

Energy Technology Data Exchange (ETDEWEB)

Magnetic properties of organic compounds with two-dimensional distorted triangular lattice structure, {beta}{sup '}-X[Pd(dmit){sub 2}]{sub 2} are investigated by the muon spin relaxation ({mu}SR) method, where X is counter cation. We have previously reported that the X=Me{sub 4}P salt (1, Me=CH{sub 3}) shows a very sharp antiferromagnetic (AFM) transition at 39.3K. We have carried out {mu}SR measurements on other two Pd(dmit){sub 2} salts: the X=Et{sub 2}Me{sub 2}P salt (2, Et=C{sub 2}H{sub 5}) and the Et{sub 2}Me{sub 2}Sb salt (3). In compound 2, an AFM transition at lower T{sub N}=15K with a smaller enhancement of the muon spin relaxation is observed, indicating a larger effect of the spin frustration than in 1. The zero-field {mu}SR time spectra of 3 showed an enhancement of the relaxation below {approx}80K, but did not show precessions. Recently, it has been suggested that this salt undergoes a phase transition to a charge-separated nonmagentic state. It is expected that the enhancement of the relaxation is related to the spin localization attributable to the charge separation.

Ohira, S. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)]. E-mail: ohira@riken.jp; Tamura, M. [Condensed Molecular Materials Laboratory, RIKEN, JST-CREST, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kato, R. [Condensed Molecular Materials Laboratory, RIKEN, JST-CREST, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Iwasaki, M. [Advanced Meson Science Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2006-03-31

346

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples  

Science.gov (United States)

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00 ?g mL-1, 5.0 ng mL-1, 0.9993 and 2.8% (n = 3, c = 4.00 ?g mL-1), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples.

Chen, Jieping; Zhu, Xiashi

2015-02-01

347

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples.  

Science.gov (United States)

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00 ?g mL(-1), 5.0 ng mL(-1), 0.9993 and 2.8% (n=3, c=4.00 ?g mL(-1)), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples. PMID:25238184

Chen, Jieping; Zhu, Xiashi

2015-02-25

348

Joint interpretation of gravity and magnetic data in the Kolárovo anomaly region by separation of sources and the inversion method of local corrections  

Science.gov (United States)

We present a new interpretation of the Kolárovo gravity and magnetic anomalies in the Danube Basin based on an inversion methodology that comprises the following numerical procedures: removal of regional trend, depth-wise separation of signal of sources, approximation of multiple sources by 3D line segments, non-linear inversion based on local corrections resulting in found sources specified as 3D star-convex homogenous bodies and/or 3D contrasting structural contact surfaces. This inversion methodology produces several admissible solutions from the viewpoint of potential field data. These solutions are then studied in terms of their feasibility taking into consideration all available tectono-geological information. By this inversion methodology we interpret here the Kolárovo gravity and magnetic anomalies jointly. Our inversion generates several admissible solutions in terms of the shape, size and location of a basic intrusion into the upper crust, or the shape and depth of the upper/lower crust interface, or an intrusion into the crystalline crust above a rise of the mafic lower crust. Our intrusive bodies lie at depths between 5 and 12 km. Our lower crust elevation rises to 12 km with and 8 km without the accompanying intrusion into the upper crust, respectively. Our solutions are in reasonable agreement with various previous interpretations of the Kolárovo anomaly, but yield a better and more realistic geometrical resolution for the source bodies. These admissible solutions are next discussed in the context of geological and tectonic considerations, mainly in relation to the fault systems.

Prutkin, Ilya; Vajda, Peter; Bielik, Miroslav; Bezák, Vladimír; Tenzer, Robert

2014-04-01

349

Kinetic, isotherm and thermodynamic investigations of phosphate adsorption onto core-shell Fe3O4@LDHs composites with easy magnetic separation assistance.  

Science.gov (United States)

In this study, three different magnetic core-shell Fe3O4@LDHs composites, Fe3O4@Zn-Al-, Fe3O4@Mg-Al-, and Fe3O4@Ni-Al-LDH were prepared via a rapid coprecipitation method for phosphate adsorptive removal. The composites were characterized by XRD, FTIR, TEM, VSM and BET analyses. Characterization results proved the successful synthesis of core-shell Fe3O4@LDHs composites with good superparamagnetisms. Batch experiments were conducted to study the adsorption efficiency of phosphate. Optimal conditions for the phosphate adsorption were obtained: 0.05g of adsorbent, solution pH of 3, and contact time of 60min. Proposed mechanisms for the removal of phosphate species onto Fe3O4@LDHs composites at different initial solution pH were showed. The kinetic data were described better by the pseudo-second-order kinetic equation and KASRA model. The adsorption isotherm curves showed a three-region behavior in the ARIAN model. It had a good fit with Langmuir model and the maximum adsorption capacity followed the order of Fe3O4@Zn-Al-LDH>Fe3O4@Mg-Al-LDH>Fe3O4@Ni-Al-LDH. Thermodynamic analyses indicated that the phosphate adsorption process was endothermic and spontaneous in nature. The three Fe3O4@LDHs composites could be easily separated from aqueous solution by the external magnetic field in 10s. These novel magnetic core-shell Fe3O4@LDHs adsorbents may offer a simple single step adsorption treatment option to remove phosphate from water without the requirement of pre-/post-treatment for current industrial practice. PMID:25778739

Yan, Liang-Guo; Yang, Kun; Shan, Ran-Ran; Yan, Tao; Wei, Jing; Yu, Shu-Jun; Yu, Hai-Qin; Du, Bin

2015-06-15

350

Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol complex from environmental and biological samples.  

Science.gov (United States)

A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid-liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40?gL(-1) and 100, respectively. The relative standard deviation (RSD) of 50?gL(-1) Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1-101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples. PMID:24398463

Khan, Sumaira; Kazi, Tasneem Gul; Soylak, Mustafa

2014-04-01

351

Neptunium separations  

International Nuclear Information System (INIS)

Two procedures for the separation of Np are presented; the first involves separation of 239Np from irradiated 238U, and the second involves separation of 237Np from a solution representing that from a dissolved fuel element

352

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

353

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 (r2) at 4.7 T and room temperature in the range of 60 to 300 mM-1s-1, depending on the particle size. This size regulation method has great promise for applications that require homogeneous-sized MNPs made by an aqueous solution coprecipitation method. Any group of the CoFe2O4 MNPs could be used as initial base cores of MRI T2 CAs, with almost unique T2 relaxivity owing to size regulation. The methodology reported here opens up many possibilities for biosensing applications and disease diagnosis. PACS: 75.75.Fk, 78.67.Bf, 61.46.Df. PMID:24004536

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

2013-01-01

354

Magnetically separable reactive sorbent based on the CeO2/?-Fe2O3 composite and its utilization for rapid degradation of the organophosphate pesticide parathion methyl and certain nerve agents.  

Czech Academy of Sciences Publication Activity Database

Ro?. 262, FEB (2015), s. 747-755. ISSN 1385-8947 R&D Projects: GA ?R(CZ) GAP106/12/1116 Institutional support: RVO:61388980 Keywords : Magnetically separable sorbent * Destructive sorption * Cerium oxide * Parathion methyl * Toxic organophosphates Subject RIV: CA - Inorganic Chemistry Impact factor: 4.058, year: 2013

Janoš, P.; Kurá?, P.; Pila?ová, V.; Trögl, J.; Š?astný, M.; Pelant, O.; Henych, Ji?í; Bakardjieva, Snejana; Životský, O.; Kormunda, M.; Mazanec, K.; Skoumal, M.

2015-01-01

355

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

356

Magnetic isotope effect on the thermolysis of 9,10-diphenylanthracene endoperoxide as a means of separation of 17O from 16O and 18O  

International Nuclear Information System (INIS)

The results appear to be consistent with the postulate that the thermolysis of 9,10-diphenylanthracene endoperoxide (DPA-O2) produces a mixture of singlet oxygen and triplet oxygen as primary products via an initial singlet diradicaloid intermediate which can either fragment to yield singlet oxygen or intersystem cross to yield a triplet diradicaloid which can fragment to yield triplet oxygen. When the singlet diradicaloid possesses an 17O atom which can interact, via hyperfine coupling, with an electron spin, the rate of intersystem crossing is accelerated relative to the rate for singlet diradicaloids that possess only 16O or 18O atoms. The experimental manifestations of this magnetic isotope effect are a lower quantum yield for singlet oxygen formation in 17O-enriched DPA-O2 and a selective isotopic enrichment of 17O in the untrappable molecular oxygen generated in the thermolysis of DPA-O2. These results appear to represent the first of selective separation of a middle isotope by a chemical process. 1 table, 3 figures

357

Preparation of magnetically separable Fe{sub 3}O{sub 4}/BiOI nanocomposites and its visible photocatalytic activity  

Energy Technology Data Exchange (ETDEWEB)

Novel magnetic Fe{sub 3}O{sub 4}/BiOI nanocomposites with visible light response were successfully fabricated through a facile and economical method at low temperature and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), respectively. The Fe{sub 3}O{sub 4}/BiOI nanocomposites were further employed in photodegrading rhodamine B (RhB). After 40 min, RhB removal rate reached to 90.1%, which was superior to the pure BiOI (50.3%). The enhanced photocatalytic performance of Fe{sub 3}O{sub 4}/BiOI nanocomposites may be attributed to the separation efficiency of the carriers. After five recycles for the photodegradation of RhB, the Fe{sub 3}O{sub 4}/BiOI nanocomposites did not exhibit any significant loss of activity, confirming the photocatalyst was essentially stable. Moreover, direct hole transfers and ·O{sub 2}{sup ?} are proved to be the dominant reactive species in the photodegradation of RhB over Fe{sub 3}O{sub 4}/BiOI nanocomposites.

Li, Xiangwei; Niu, Chenggang, E-mail: cgniu@hnu.edu.cn; Huang, Dawei; Wang, Xiaoyu; Zhang, Xuegang; Zeng, Guangming, E-mail: zgming@hnu.edu.cn; Niu, Qiuya

2013-12-01

358

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

359

MAGNET  

CERN Document Server

  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

360

Separations chemistry  

International Nuclear Information System (INIS)

Studied are: statistical thermodynamics of liquids, liquid crystals, and micelles (polymers), stability quotients of lanthanide cryptates, HPLC separation of Zr and Hf, recovery of U from wet-process phosphoric acid, and separations by filtrations. 10 figures

361

MAGNET  

CERN Document Server

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

B. Curé

2011-01-01

362

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

363

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

364

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

CERN Document Server

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

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

2003-01-01

365

Low-temperature magnetization step and its training effects in phase-separated La0.5Ca0.5MnO3  

International Nuclear Information System (INIS)

We observed a magnetization step accompanied by a metal-insulator transition around 75 K in La0.5Ca0.5MnO3. Repeating measurements under the same condition weaken the magnetization step and enhance the resistance at low temperature. The decayed magnetization step reappears after annealing the sample at high temperature or cooling it under a magnetic field. The low-temperature magnetization step can be attributed to the melting of the overcooled ferromagnetic fragments and its training effect may be related to structure distortions at the interfaces between the ferromagnetic and charge-ordered phases in the investigated system. (author)

366

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

367

Optics of mass separator I  

International Nuclear Information System (INIS)

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

368

55Mn NMR Study of the Field-Controlled Magnetic Phase Separation in (La0.25Pr0.75)0.7Ca0.3MnO3 with Different Oxygen Isotope Content  

CERN Document Server

An influence of the 16O-18O isotope substitutions on magnetic state of perovskite-type manganite (La0.25Pr0.75)0.7Ca0.3MnO3 is studied by 55Mn NMR. Successive cycling with an isochronal exposure at different magnetic fields up to H=8T is used to study the field-induced transition from antiferromagnetic insulating (AFI) state to the ferromagnetic metal (FMM) one in the 18O-enriched sample. After exposure at H>H_{cr} \\sim 5.3T the NMR spectrum of the 18O-sample evidences for magnetic phase separation (PS) resulted in the coexisting AFI and FMM domains. Further increase of exposing field leads to a progressive growth of the FMM phase at the expense of AFI domains. Its relative fraction can be controlled by external magnetic field and the resulting magnetic structure in the PS region is discussed. Anomalous T-dependence of the 55Mn nuclear spin-lattice relaxation rate is revealed in the FMM state of both 16O-and 18O-enriched samples. The manifestation of the Pr magnetic ordering at T \\sim 40K is considered.

Gerashenko, A P; Kumagai, K; Verkhovskii, S V; Mikhalev, K N; Yakubovskii, A

2002-01-01

369

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.

370

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

371

Ag/SiO2 core-shell nanoparticle-based surface-enhanced Raman probes for immunoassay of cancer marker using silica-coated magnetic nanoparticles as separation tools.  

Science.gov (United States)

A simple, sensitive and highly specific immunoassay has been developed based on surface-enhanced Raman scattering for human alpha-fetoprotein (AFP), a tumor marker for the diagnosis of hepatocellular carcinoma. This strategy combines the Ag/SiO2 core-shell nanoparticles embedded with rhodamine B isothiocyanate dye molecules as Raman tags and the amino group modified silica-coated magnetic nanoparticle as immobilization matrix and separation tool. In the proposed system, a sandwich-type immunoassay was performed between polyclonal antibody functionalized Ag/SiO2 nanoparticle-based Raman tags and monoclonal antibody modified silica-coated magnetic nanoparticles. The presence of the analyte and the reaction between the antigen and antibody can be monitored by the Raman spectra of the Ag/SiO2 tags. Compared to the previous surface-enhanced Raman immunoassays, the main advantage of this strategy lies in two aspects. One is the high stability of Raman tags derived from the silica shell-coated silver core-shell nanostructure. The other is the use of silica-coated magnetic nanoparticles as immobilization matrix and separation tool, thus avoiding complicated pretreatment and washing steps. We have studied in detail the experimental parameters such as the effects of the antibody concentration modified on the Raman tags and on the magnetic particles, and the immunoreaction time. Using this strategy, concentration of human AFP up to 0.12 microg/ml was detected with a detection limit of 11.5 pg/ml. PMID:16971110

Gong, Ji-Lai; Liang, Yi; Huang, Yong; Chen, Ji-Wei; Jiang, Jian-Hui; Shen, Guo-Li; Yu, Ru-Qin

2007-02-15

372

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 235U enrichment is demonstrated. (UK)

373

Isotopic separation  

International Nuclear Information System (INIS)

A method and apparatus are provided for separating isotopes in an atomic or molecular mixture. The isotropic recoil momenta resulting from selective excitation and ionization of an atomic beam are used to mechanically separate a desired isotope from the beam. Similarly, the isotropic recoil momenta resulting from selective photon excitation and promotion of dissociative electron attachment of a molecular beam of uranium hexafluoride are used preparatory to mechanical separation. The isotropic recoil momenta resulting from multi-photon dissociation recoil in a molecular beam of UF6 or SF6 is also used for separation. Matrix formation of UF5 in HBr so as to collapse the ?3 vibrational mode of the UF6 molecule is used in conjunction with selective isotopic excitation to promote reduction of UF6 molecules containing U235 and facilitate simplified separation

374

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  

Energy Technology Data Exchange (ETDEWEB)

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.

Takeda, Hiroyuki, E-mail: takeda@ribf.riken.jp [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kubo, Toshiyuki; Kusaka, Kensuke; Suzuki, Hiroshi; Inabe, Naohito [RIKEN Nishina Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Nolen, Jerry A. [Argonne National Laboratory (ANL), 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

2013-12-15

375

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

376

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

377

Isotopic separation  

International Nuclear Information System (INIS)

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

378

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

379

Charge transport in Ho$_x$Lu$_{1-x}$B$_{12}$: Separating Positive and Negative Magnetoresistance in Metals with Magnetic Ions  

OpenAIRE

The magnetoresistance (MR) $\\Delta \\rho/\\rho$ of cage-glass compound Ho$_x$Lu$_{1-x}$B$_{12}$ with various concentration of magnetic holmium ions ($x$$\\leq$0.5) has been studied in detail concurrently with magnetization M(T) and Hall effect investigations on high quality single crystals at temperatures 1.9-120 K and in magnetic field up to 80 kOe. The undertaken analysis of $\\Delta\\rho/\\rho$ allows us to conclude that the large negative magnetoresistance (nMR) observed in vi...

Sluchanko, N. E.; Khoroshilov, A. L.; Anisimov, M. A.; Azarevich, A. N.; Bogach, A. V.; Glushkov, V. V.; Demishev, S. V.; Krasnorussky, V. N.; Voronov, V. V.; Shitsevalova, N. Yu; Filippov, V. B.; Levchenko, A. V.; Pristas, G.; Gabani, S.; Flachbart, K.

2014-01-01

380

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

OpenAIRE

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 resultin...

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

2013-01-01

381

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

Czech Academy of Sciences Publication Activity Database

Ro?. 321, ?. 10 (2009), s. 1667-1670. ISSN 0304-8853. [International Conference on Scientific and Clinical Applications of Magnetic Carriers /7./. Vancouver, 20.05.2008-24.05.2008] R&D Projects: GA ?R GA203/09/1242 Institutional research plan: CEZ:AV0Z40500505 Keywords : magnetic microsphere * P(HEMA-co-GMA) * DNA isolation Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.204, year: 2009

Rittich, B.; Španová, A.; Šálek, P.; N?mcová, P.; Trachtová, Š.; Horák, Daniel

2009-01-01

382

MAGNET  

CERN Multimedia

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

383

Current switching and slow magnetic relaxation behaviour in phase-separated Ca{sub 0.85}La{sub 0.15}MnO{sub 3} system showing colossal electroresistance  

Energy Technology Data Exchange (ETDEWEB)

From the study of current-voltage (I-V) characteristics, current switching (at temperatures {<=}100 K) has been observed in the electron doped charge-ordered polycrystalline manganite Ca{sub 0.85}La{sub 0.15}MnO{sub 3}. The threshold switching voltage is found to decrease with an increase in temperature. The sample also shows colossal electroresistance (ER) when resistance is measured using various measuring currents. The ER, interestingly, undergoes an unusual sign change from negative to positive at a temperature (T{sub t}) ascending with increasing applied current. These effects are analysed in terms of electric field induced collapse of the charge-ordered state and modification of percolative conduction by the applied field, within the phase separation scenario. The phase separation hypothesis has been verified by magnetic relaxation measurements.

Bose, Esa; Chaudhuri, B K [Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata-700032 (India); Chan, C L; Yang, H D [Department of Physics, Center for Nanoscience and Nanotechnology, National Sun Yat Sen University, Kaohsiung-804, Taiwan (China)], E-mail: sspbkc@iacs.res.in

2008-11-21

384

Nano-CuFe2O4 as a magnetically separable and reusable catalyst for the synthesis of diaryl/aryl alkyl sulfides via cross-coupling process under ligand-free conditions.  

Science.gov (United States)

An efficient protocol was developed for the CuFe(2)O(4) nanopowder-catalyzed aryl-sulfur bond formation between aryl halide and thiol/disulfide. A variety of aryl sulfides were synthesized in impressive yields with good chemoselectivity and functional group tolerance in the presence of a catalytic amount of CuFe(2)O(4), Cs(2)CO(3) as base, in nitrogen atmosphere, under ligand-free conditions, in DMSO as solvent at 100 °C. The catalyst is air-stable, inexpensive, magnetically separable and recyclable up to four cycles. PMID:21769376

Swapna, Kokkirala; Murthy, Sabbavarapu Narayana; Jyothi, Mocharla Tarani; Nageswar, Yadavalli Venkata Durga

2011-09-01

385

Separation research  

International Nuclear Information System (INIS)

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

386

Atomic lithium vapor laser isotope separation  

CERN Document Server

An atomic vapor laser isotope separation in lithium was performed using tunable diode lasers. The method permits also the separation of the isotopes between the sup 6 LiD sub 2 and the sup 7 LiD sub 1 lines using a self-made mass separator which includes a magnetic sector and an ion beam designed for lithium. (Author)

Olivares, I E

2002-01-01

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)  

Science.gov (United States)

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 metastable phase generated due to kinetic arrest of the first order transformation in all the films. Like structural glasses, these magnetic glass-like phases show evidence of devitrification of the arrested charge order antiferromagnetic insulator (CO-AFI) phase to the equilibrium ferromagnetic metallic (FMM) phase with isothermal increase of magnetic field and/or iso-field warming. These measurements also clearly show the equilibrium ground state of this system to be FMM and the metastable glass-like phase to be AFI phase.

Sathe, V. G.; Ahlawat, Anju; Rawat, R.; Chaddah, P.

2010-05-01

388

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 metastable phase generated due to kinetic arrest of the first order transformation in all the films. Like structural glasses, these magnetic glass-like phases show evidence of devitrification of the arrested charge order antiferromagnetic insulator (CO-AFI) phase to the equilibrium ferromagnetic metallic (FMM) phase with isothermal increase of magnetic field and/or iso-field warming. These measurements also clearly show the equilibrium ground state of this system to be FMM and the metastable glass-like phase to be AFI phase.

389

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 foin 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

390

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-01-26

391

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

International Nuclear Information System (INIS)

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA-co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

392

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

Science.gov (United States)

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate) (P(HEMA- co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA- co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

Rittich, Bohuslav; Španová, Alena; Šálek, Petr; N?mcová, Petra; Trachtová, Št?pánka; Horák, Daniel

2009-05-01

393

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

Energy Technology Data Exchange (ETDEWEB)

Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA-co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

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

2009-05-15

394

Phase separation in thermoelectric delafossite CuFe1-xNixO2 observed by soft x-ray magnetic circular dichroism  

Science.gov (United States)

Electronic structures of Ni-doped CuFe1-xNixO2 delafossite oxides (0 ? x ? 0.03) have been investigated by employing soft x-ray magnetic circular dichroism (XMCD). Finite XMCD signals are observed for Fe, Ni, and Cu 2p states, and valence states of Cu, Fe, and Ni ions are nearly monovalent (Cu+), trivalent (Fe3+), and divalent (Ni2+), respectively, for all x ? 0.03. Tiny magnetic impurities could be detected by employing XMCD. Fe and Ni 2p XMCD signals are identified due to ferrimagnetic spinel impurities of CuFe2O4 and NiFe2O4. XMCD signals for Cu 2p states arise from divalent Cu2+ ions. Thermoelectrical properties are found to be very sensitive to the very little impurity phase present in delafossite oxides.

Kang, J.-S.; Kim, D. H.; Hwang, Jihoon; Lee, Eunsook; Nozaki, T.; Hayashi, K.; Kajitani, T.; Park, B.-G.; Kim, J.-Y.; Min, B. I.

2011-07-01

395

Two novel calixarene functionalized iron oxide magnetite nanoparticles as a platform for magnetic separation in the liquid–liquid/solid–liquid extraction of oxyanions  

Energy Technology Data Exchange (ETDEWEB)

This article focuses on the syntheses of 25,27-bis[3-(N-ethylsulfonic acid)aminopropxy]-26,28-dihydroxy-5,11,17,23-tetra-tert-butyl-calix[4]arene (3) and 25,27-bis[3-(N-ethyl-dihydrogen phosphate)aminopropxy]-26,28-dihydroxy-5,11,17,23-tetra-tert-butyl-calix[4] arene (4) as well as their immobilization onto [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane-modified Fe{sub 3}O{sub 4} magnetite nanoparticles, and the extraction abilities of four new extractants which were characterized by a combination of FTIR, {sup 1}H NMR, elemental analyses, transmission electron microscopy (TEM) and thermogravimetric analyses (TGA) involving electrostatic and hydrogen bonding interactions between the calixarene and oxide anions such as arsenate and dichromate anions. The extraction results indicate that these new calixarene derivatives having high extraction capabilities would be used as effective extractants for the removal of the dichromate/arsenate ions from water. - Highlights: ? Two novel calix[4]arene appended magnetic nanoparticles have been synthesized. ? Calixarene-grafted magnetic nanoparticles are becoming a hot topic. ? Long-term exposure to As(V)/Cr(VI) contaminated water causes various types of cancers. ? Clx-MNs have been effectively used for the extraction of toxic oxyanions. ? Two novel calix[4]arene appended magnetic nanoparticles have been synthesized.

Sayin, Serkan; Ozcan, Fatih; Yilmaz, Mustafa, E-mail: myilmaz42@yahoo.com

2013-05-01

396

Two novel calixarene functionalized iron oxide magnetite nanoparticles as a platform for magnetic separation in the liquid–liquid/solid–liquid extraction of oxyanions  

International Nuclear Information System (INIS)

This article focuses on the syntheses of 25,27-bis[3-(N-ethylsulfonic acid)aminopropxy]-26,28-dihydroxy-5,11,17,23-tetra-tert-butyl-calix[4]arene (3) and 25,27-bis[3-(N-ethyl-dihydrogen phosphate)aminopropxy]-26,28-dihydroxy-5,11,17,23-tetra-tert-butyl-calix[4] arene (4) as well as their immobilization onto [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane-modified Fe3O4 magnetite nanoparticles, and the extraction abilities of four new extractants which were characterized by a combination of FTIR, 1H NMR, elemental analyses, transmission electron microscopy (TEM) and thermogravimetric analyses (TGA) involving electrostatic and hydrogen bonding interactions between the calixarene and oxide anions such as arsenate and dichromate anions. The extraction results indicate that these new calixarene derivatives having high extraction capabilities would be used as effective extractants for the removal of the dichromate/arsenate ions from water. - Highlights: ? Two novel calix[4]arene appended magnetic nanoparticles have been synthesized. ? Calixarene-grafted magnetic nanoparticles are becoming a hot topic. ? Long-term exposure to As(V)/Cr(VI) contaminated water causes various types of cancers. ? Clx-MNs have been effectively used for the extraction of toxic oxyanions. ? Two novel calix[4]arene appended magnetic nanoparticles have been synthesized

397

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

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 ?g L(-1) and 0.04-3 ?g L(-1), respectively. Detection limit was 0.041 ?g L(-1) for AFB1 and 0.013 ?g L(-1) for AFB2. The proposed method was successfully applied to the determination of AFB1 and AFB2 in spiked corn and rice samples with an average recovery of 93.5%. The results demonstrated that the developed method is simple, rapid, inexpensive, accurate and remarkably free from interference effects. PMID:24814005

Hashemi, Mahdi; Taherimaslak, Zohreh; Rashidi, Somayeh

2014-06-01

398

The Swarm End-to-End mission simulator study: A demonstration of separating the various contributions to Earth's magnetic field using synthetic data  

DEFF Research Database (Denmark)

Swarm, a satellite constellation to measure Earth's magnetic field with unpreceded accuracy, has been selected by ESA for launch in 2009. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system by improving our understanding of the Earth's interior and climate. An End-to-End mission performance simulation was carried out during Phase A of the mission, with the aim of analyzing the key system requirements, particularly with respect to the number of Swarm satellites and their orbits related to the science objectives of Swarm. In order to be able to use realistic parameters of the Earth's environment, the mission simulation starts at January 1, 1997 and lasts until re-entry of the lower satellites five years later. Synthetic magnetic field values were generated for all relevant contributions to Earth's magnetic field: core and lithospheric fields, fields due to currents in the ionosphere and magnetosphere, due to theirsecondary, induced, currents in the oceans, lithosphere and mantle, and fields due to currents coupling the ionosphere and