WorldWideScience
1

High gradient magnetic separation  

International Nuclear Information System (INIS)

In a process in which magnetic material is trapped in a filter disposed in a magnetic field, and is unloaded by passing a fluid through the filter in the absence of the initial magnetic field, the magnetic field is first reduced to an intermediate value to allow unloading of the more weakly magnetic particles, the more strongly magnetic particles being retained and subsequently unloaded by further reduction of the magnetic field. Stage by stage reduction of the magnetic field during unloading allows separation of different species from the mixture. As an example the method can be applied to the separation of uranium compounds from mine ores. The uranium compounds are magnetic, while most of the other constituents of the ore are non-magnetic. The starting material is a suspension of the ore. Water is used for unloading. The filter material in this case is stainless steel balls. (author)

2

A magnetic separator  

Energy Technology Data Exchange (ETDEWEB)

A magnetic separator is proposed which includes a nonmagnetic drum installed in a bath with the capability of rotation, a magnetic system installed in the drum and made out of magnetic units with polarity which alternate along the course of rotation of the drum, loading and unloading devices and a flocculator located in the loading device and made of permanent magnets. In order to increase the effectiveness of the separation process, the permanent magnets are made ring shaped, while a plate of a magnetic material is positioned on the internal surface of the bath adjacent to the flocculator and is turned towards the drum by the surface which has a polarity opposite the first unit of magnets. The magnetic plate is made of a magnetophore.

Panov, O.V.; Bikbov, A.A.; Maltsev, B.A.; Zobnin, B.B.

1982-01-01

3

[Separation of magnetic bacteria by using a magnetic separator].  

Science.gov (United States)

A magnetic separator was used to separate magnetic bacteria based on their magnetotactic characteristics. Acidithiobacillus ferrooxidans, a bacterium that could synthesize intra-cellular nanometer magnetic particles, was investigated as an example. Strong magnetic and weak magnetic cells were separated and collected. On average, the number of the magnetic particles present in the strong magnetic cells is more than that of the weak magnetic cells. Moreover, semisolid-plate magnetophoresis showed that the magnetotaxis of strong magnetic cells was stronger than the weak magnetic cells. These results suggest that the magnetic separator can be used to isolate the magnetic bacteria, which will facilitate the research of magnetic bacteria. PMID:20432949

Liu, Xinxing; Guo, Ning; Yang, Yingjie; Liang, Wanjie; Zhang, Jian

2010-02-01

4

USE OF SUPERCONDUCTING MAGNETS IN MAGNETIC SEPARATION  

OpenAIRE

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

Parker, M

1984-01-01

5

Magnetic separation in microfluidic systems  

OpenAIRE

This Ph.D. thesis presents theory, modeling, design, fabrication, experiments and results for microfluidic magnetic separators. A model for magnetic bead movement in a microfluidic channel is presented, and the limits of the model are discussed. The effective magnetic field gradient is defined, and it is argued that it is a good measure, when comparing the performance of magnetic bead separators. It is described how numeric modelling is used to aid the design of microfluidic...

Smistrup, Kristian; Hansen, Mikkel Fougt; Bruus, Henrik; Tang, Peter Torben; Kruhne, Ulrich Willi Walter

2007-01-01

6

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

7

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

8

Cryogenic system for the superconducting magnetic separator  

International Nuclear Information System (INIS)

An industrial-scale magnetic separator for cleaning of kaolin clay has recently been designed and installed in Czechoslovakia. The superconducting system of the separator is able to build up a magnetic field up to 5 T in the working space of the separator, whose active cavity dimensions are 0 560 x length 1320 mm. The cryogenic system comprises two helium liquefiers of different concept, one of them operating on a piston type expander, the other one with an expansion turbine

9

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

10

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

11

Superconducting magnet with separate support system  

International Nuclear Information System (INIS)

This patent describes a superconducting magnet arrangement for MRI systems. The system comprising: a vacuum vessel, a liquid helium vessel within the vacuum vessel, magnetic coils for accomplishing magnetic resonance imaging (MRI). The coils being located within the liquid helium vessel, a nitrogen vessel within the vacuum vessel located further from the center of the vacuum vessel than the helium vessel. The vacuum vessel functioning to maintain an internal vacuum but being non-supportive of the vessels therein and separate from the vessel therein, and separate support means attached to the vacuum vessel for supporting the vacuum vessel and the contents of the vacuum vessel

12

Microfluidic magnetic separator using an array of soft magnetic elements  

DEFF Research Database (Denmark)

We present the design, fabrication, characterization, and demonstration of a new passive magnetic bead separator. The device operates in an effective state when magnetized by an external magnetic field of only 50 mT, which is available from a tabletop electromagnet. We demonstrate the complete capture of 1.0 mu m fluorescent magnetic beads from a 7.5 mu L sample volume traveling at an average linear fluid velocity of 5 mm/s.

Smistrup, Kristian; Lund-Olesen, Torsten

2006-01-01

13

Coal desulfurization by magnetic separation methods  

Energy Technology Data Exchange (ETDEWEB)

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separations of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conduced on Korean anthracite and high sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the operating parameters studied include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages, etc. The results show that for wet separation, the total sulfur of 60-70% was removed from coals with over 80% combustible recovery, on the other hand, for dry separation total sulfur of 47.6% was removed from coals with 75% recovery. (author). 8 refs., 2 tabs., 9 figs.

Choi, Woo Zin [Suwon Univ., Suwon (Korea, Republic of); Jeon, Ho Seok [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of); Chung, Jin Do; Ji, Pyung Sam [Korea Electric Power Co., Seoul (Korea, Republic of)

1995-10-01

14

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

15

Electromagnetic Isotope Separator: Magnetic Measurement: Results  

International Nuclear Information System (INIS)

The electromagnetic isotope separator of the University of Grenoble can produce isotope with a great purity. It has two magnets with non homogeneous field. The magnetic fields have been corrected with shims in order to obtain an accuracy of ±10-4 in the useful region. These shims have been determined experimentally by measurements. The great enrichment factors obtained, prove the quality of this apparatus. (author)

16

Magnetic phase separation in ordered alloys  

OpenAIRE

We present a lattice model to study the equilibrium phase diagram of ordered alloys with one magnetic component that exhibits a low temperature phase separation between paramagnetic and ferromagnetic phases. The model is constructed from the experimental facts observed in Cu$_{3-x}$AlMn$_{x}$ and it includes coupling between configurational and magnetic degrees of freedom which are appropriated for reproducing the low temperature miscibility gap. The essential ingredient for...

Marcos, Jordi; Vives I Santa-eula?lia, Eduard; Casta?n I Vidal, Maria Teresa

2001-01-01

17

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

International Nuclear Information System (INIS)

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

18

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

International Nuclear Information System (INIS)

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

19

Integrated acoustic and magnetic separation in microfluidic channels  

DEFF Research Database (Denmark)

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

Adams, Jonathan; Thevoz, Patrick

2009-01-01

20

Magnetic separation of micro-spheres from viscous biological fluids  

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-02-21

21

Magnetic separation of micro-spheres from viscous biological fluids  

Science.gov (United States)

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

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

2007-02-01

22

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

23

Magnetically separable composite photocatalyst with enhanced photocatalytic activity.  

Science.gov (United States)

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

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

2008-12-30

24

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

2014-09-01

25

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

26

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

27

Electron spin separation without magnetic field.  

Science.gov (United States)

A nanodevice capable of separating spins of two electrons confined in a quantum dot formed in a gated semiconductor nanowire is proposed. Two electrons confined initially in a single quantum dot in the singlet state are transformed into the system of two electrons confined in two spatially separated quantum dots with opposite spins. In order to separate the electrons' spins we exploit transitions between the singlet and the triplet state, which are induced by resonantly oscillating Rashba spin-orbit coupling strength. The proposed device is all electrically controlled and the electron spin separation can be realized within tens of picoseconds. The results are supported by solving numerically the quasi-one-dimensional time-dependent Schroedinger equation for two electrons, where the electron-electron correlations are taken into account in the exact manner. PMID:25106038

Paw?owski, J; Szumniak, P; Skubis, A; Bednarek, S

2014-08-27

28

MAGNETITE RECOVERY IN COAL WASHING BY HIGH GRADIENT MAGNETIC SEPARATION  

Science.gov (United States)

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

29

Process for magnetic separation of metals from aqueous media  

International Nuclear Information System (INIS)

Paramagnetic metals are separated from aqueous media containing them in low concentration by first fixing the metals on bacterial, yeast or other cells so as to render the cells magnetic, and then separating the cells from the media by a high gradient magnetic separation technique. The metal and the cells are contacted in the presence of a compound which is converted by the cells into a product which interacts with the metal and causes it to become bound to the cells. The process is particularly useful for removing low concentrations of highly toxic or radioactive metals, e.g. uranium, from industrial effluents containing them. (author)

30

In Situ Magnetic Separation for Extracellular Protein Production  

DEFF Research Database (Denmark)

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

Kappler, T.; Cerff, Martin

2009-01-01

31

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

International Nuclear Information System (INIS)

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

32

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

International Nuclear Information System (INIS)

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 experiments with CD138-labeled MACS nanoparticles. Capture efficiencies ranging from 28% to 37% and elution efficiencies greater than 73% were measured for a single pass through the sifter.

33

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

34

Magnetic isotope effect and isotope separation in ''microreactors''  

International Nuclear Information System (INIS)

The possibility of increasing the effectiveness isotope separation in reversible radical photochemical reactions, is investigated. The effectiveness of isotope separation in the radical pair with a limited diffusion dynamics in a limited volume - ''microreactor'', is calculated. The separation effectiveness under such conditions increases considerably. Quantitative ratios between the rate constant of radical transformation, diffusion coefficient and ''microreactor'' dimensions providing the most effective enrichment, are found. The conclusion is made that reacting under conditions of limited diffusion dynamics of radical pairs opens new perspectives in isotope separation on the basis of magnetic isotopic effect

35

Novel platform for minimizing cell loss on separation process: Droplet-based magnetically activated cell separator  

Science.gov (United States)

To reduce the problem of cell loss due to adhesion, one of the basic phenomena in microchannel, we proposed the droplet-based magnetically activated cell separator (DMACS). Based on the platform of the DMACS—which consists of permanent magnets, a coverslip with a circle-shaped boundary, and an injection tube—we could collect magnetically (CD45)-labeled (positive) cells with high purity and minimize cell loss due to adhesion. To compare separation efficiency between the MACS and the DMACS, the total number of cells before and after separation with both the separators was counted by flow cytometry. We could find that the number (3241/59940) of cells lost in the DMACS is much less than that (22360/59940) in the MACS while the efficiency of cell separation in the DMACS (96.07%) is almost the same as that in the MACS (96.72%). Practically, with fluorescent images, it was visually confirmed that the statistical data are reliable. From the viability test by using Hoechst 33 342, it was also demonstrated that there was no cell damage on a gas-liquid interface. Conclusively, DMACS will be a powerful tool to separate rare cells and applicable as a separator, key component of lab-on-a-chip.

Kim, Youngho; Hong, Su; Lee, Sang Ho; Lee, Kangsun; Yun, Seok; Kang, Yuri; Paek, Kyeong-Kap; Ju, Byeong-Kwon; Kim, Byungkyu

2007-07-01

36

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.))

37

Process to remove actinides from soil using magnetic separation  

Energy Technology Data Exchange (ETDEWEB)

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

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

1996-01-01

38

The study on optimization issues for magnetic separation by magnetic chromatography  

International Nuclear Information System (INIS)

The magnetic chromatography is a very useful system for an ion and/or fine magnetic particle separation because it has strong magnetic field gradients even in a very narrow flow channel. We have not only developed the magnetic chromatography system to separate the fine particles and ions, but also the numerical analysis code based on the fluid dynamics and electromagnetism to investigate the separating characteristics and to optimize design of magnetic column. In this study, the simple experiments using a superconducting magnet with a large room-temperature-bore and a micro-scale magnetic column consisting of ferromagnetic wires were carried out to understand the ions separation. The cobalt chloride (CoCl2) and the nickel sulfate (NiSO4) were used as ions, and the magnetic field and length of magnetic column were used as a parameter in an experiment and an analysis. It can be expected that the ion mobility of a single and complex are quite different, and the ability of the separation will be improved by increasing the column length without external magnetic field.

39

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.

40

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

41

Separation of the Magnetic Field into External and Internal Parts  

DEFF Research Database (Denmark)

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

Olsen, Nils; Glassmeier, K.-H.

2010-01-01

42

Preparation of silanized magnetic nanoparticles for magnetic separation technique use  

International Nuclear Information System (INIS)

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

43

Coil geometry for efficient active compensation with separated magnetic shields  

Science.gov (United States)

We have already proposed a new method of magnetic shielding aiming for magnetocardiography, in which magnetic shells are separated and a new compensation scheme is employed to allow for wide space between them. Each magnetic shell that consists of a half of the cylinder (diameter=20 cm and length=60 cm) and two flanges at both ends of the half cylinder extending along the radial direction has a saddle coil on its outer surface with the coil's long straight section running parallel to the axis of the cylinder. In this paper, the relationship between the width of the long straight sections of the saddle coil and the efficiency of the active compensation is investigated by the finite element method (FEM) analysis and by experiments. A magnetic shield used in this study is a double shell structure where each shell is made of stacked amorphous tapes and the outer shell has a magnetic shaking coil for the enhancement of the permeability. We have found that for a given magnetic field, the compensation current necessary for a given magnetic field varies by a factor of 3 depending on the width of a saddle coil and that its value monotonically decreases with increasing the width. We have also confirmed that the phase delay of the compensation magnetic field experienced while it comes in the magnetic shell is small.

Nakashima, Yoshihiro; Sasada, Ichiro

2009-04-01

44

Magnetic separation using high-T sub c superconductors  

CERN Document Server

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

Bolt, L

2001-01-01

45

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

46

Magnetic Separations with Magnetite: Theory, Operation, and Limitations  

Energy Technology Data Exchange (ETDEWEB)

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

G. B. Cotten

2000-08-01

47

Maximizing the recovery of fine iron ore using magnetic separation  

Scientific Electronic Library Online (English)

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

M, Dworzanowski.

2012-03-01

48

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

Science.gov (United States)

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

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

2014-06-01

49

Phase separation dynamics in a two-dimensional magnetic mixture.  

Science.gov (United States)

Based on classical density functional theory (DFT), we investigate the demixing phase transition of a two-dimensional, binary Heisenberg fluid mixture. The particles in the mixture are modeled as Gaussian soft spheres, where one component is characterized by an additional classical spin-spin interaction of Heisenberg type. Within the DFT we treat the particle interactions using a mean-field approximation. For certain magnetic coupling strengths, we calculate phase diagrams in the density-concentration plane. For sufficiently large coupling strengths and densities, we find a demixing phase transition driven by the ferromagnetic interactions of the magnetic species. We also provide a microscopic description (i.e., density profiles) of the resulting non-magnetic/magnetic fluid-fluid interface. Finally, we investigate the phase separation using dynamical density functional theory, considering both nucleation processes and spinodal demixing. PMID:22260598

Lichtner, K; Archer, A J; Klapp, S H L

2012-01-14

50

[Development of new magnetic bead separation and purification instrument].  

Science.gov (United States)

The article describes the development of new magnetic bead separation and purification instrument. The main application of the instrument is to capture tubercle bacillus from sputum. It is a pretreatment instrument and provides a new platform to help doctors to diagnose bacillary phthisis. Not only could it be used for tubercle bacillus capturing, but also for gene, protein and cell separating and purification. Because the controller of the instrument is 16-bit single chip microcomputer, the cost could be greatly reduced and it will be widely used in China. PMID:25241516

Xu, Yingyuan; Chen, Yi

2014-05-01

51

Loss separation for dynamic hysteresis in magnetic thin films  

International Nuclear Information System (INIS)

We show that the properties of dynamic hysteresis in ferromagnetic thin films can be explained in terms of the theory of loss separation. Remarkably, this theory, that was originally derived for bulk metallic materials, is applicable to disordered magnetic systems under fairly general conditions regardless of the particular damping mechanism. This is confirmed by numerical simulations of a driven random-field Ising model. We re-examine several experimental data reported in the literature on dynamic hysteresis in thin films and find that all of them find a natural interpretation in terms of loss separation, reconciling the apparent lack of universality observed in different materials

52

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)

53

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

54

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

OpenAIRE

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

Yongjun Tang, Jun Zou

2013-01-01

55

Kinetic approach for the purification of nucleotides with magnetic separation.  

Science.gov (United States)

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

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

2014-11-01

56

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

57

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

58

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

OpenAIRE

A new, efficient, and highly accurate method for tracing magnetic separators in global magnetospheric simulations with arbitrary clock angle is presented. The technique is to begin at a magnetic null and iteratively march along the separator by finding where four magnetic topologies meet on a spherical surface. The technique is verified using exact solutions for separators resulting from an analytic magnetic field model that superposes dipolar and uniform magnetic fields. Gl...

Komar, C. M.; Cassak, P. A.; Dorelli, J. C.; Glocer, A.; Kuznetsova, M. M.

2013-01-01

59

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

60

On-chip Magnetic Separation and Cell Encapsulation in Droplets  

Science.gov (United States)

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

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

2012-02-01

61

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

62

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

2015-01-21

63

Hybrid magnetic field gradient, rotating wall device for enhanced colloidal magnetic affinity separations  

Science.gov (United States)

A 2.0 cm internal diameter 1 m long, axially-rotating horizontal glass tube, with four axially located repeating hybrid magnetic units, is used as part of a flow-through, colloidal magnetic affinity separation device. Each magnetic unit consists of an alternating current solenoid surrounding the chamber followed by four azimuthally distributed permanent magnets that rotate with the chamber. The separation is demonstrated on a model feed system consisting of a mixture of 1.0 ?m diameter biotinylated latex beads (targets) and 9.7 ?m diameter non-functionalized latex beads (non-targets) at a 1:1 number ratio. Two feed flow rates of 12 ml/min and 35 ml/min were used until a total of 600 ml of sample were processed for each. At the low rate we achieved capture efficiency 60%, a separation factor of 18.2 with 95% purity. For the higher flow rate, the capture efficiency was 40%, the separation factor 18.6 with 87% purity. The same device also was used for removal of cadmium ions from a cadmium sulfate solution. Two arrangements for the magnetic units were used. In the first configuration, four hybrid pairs were distributed axially-each pair consisted of an alternating current carrying solenoid, followed by four azimuthally distributed permanent magnets that rotate with the chamber. In the second configuration, all four solenoids were placed first, followed by the four sets of four azimuthally distributed permanent magnets. 1-10 ?m diameter magnetic particles with iron oxide nanoparticles embedded within a quaternary ammonium cellulose matrix (MagaCell- Q, Cortex Biochem) at a starting 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 35 mL/min. For the arrangement, the cadmium concentration at the exit of the third stage dropped to 0.97 mg/L. The second configuration produced a final cadmium concentration of 0.68 mg/L. For the first arrangement, three stage processing resulted in an overall ~90% w/w cadmium removal, and the second configuration removed ~94% of the original cadmium ions. The operating mode of this device requires a periodic interruption of the feed flow, leading to down time. Thus there is a compelling motivation to the development of the continuous device. The continuous, hybrid magnetic field gradient separation device, designed in our lab, incorporates a 1.0 cm internal diameter 1m long, axially-rotating horizontal glass tube, with four axially located repeating magnetic units. Each magnetic unit consists of an alternating current solenoid surrounding the chamber followed by electromagnets at a distance of 4.0 cm from the end of the solenoid. A computer controlled DC current flowing in the electromagnet is used to generate radial magnetic field gradients within the tube, allowing magnetic particles to be drawn to the walls. MagaCell-Q magnetic particles were used to demonstrate the removal of cadmium ions from an aqueous solution. Three stage processing resulted in an overall ~92% cadmium removal. Thus, this breakthrough technology in continuous separation can lead to a large increase in processing volume and reduced down time compared to the flow-through device, without loss of removal efficiency. While the specific system studied here consists of removal of cadmium ions from an aqueous solution, the general principle of magnetic colloidal separation using the flow-through and continuous devices can be exploited for other environmental and biotechnological applications where large volumes of sample must be processed with high efficiency.

Ghebremeskel, Alazar Negusse

64

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

65

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

66

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

Science.gov (United States)

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

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

2014-11-01

67

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

68

Magnetic separation - Advanced nanotechnology for future nuclear fuel recycle  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-01

69

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)

70

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

Energy Technology Data Exchange (ETDEWEB)

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

Mishima, F. [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan)], E-mail: f-mishijima@see.qb.eng.osaka-u.ac.jp; Takeda, S. [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan); Fukushima, M. [Eishin Co., Ltd., 10-6 Minami-Saiwai, Kaita, Aki, Hiroshima 736-0032 (Japan); Nishijima, S. [Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565-0871 (Japan)

2007-10-01

71

Separation of Charged Particles from Magnetic Field Lines in Two-Component Magnetic Turbulence  

Science.gov (United States)

In interplanetary space, the transport of energetic charged particles is influenced by a turbulent magnetic field. Previous studies have shown that a two-component (2D+slab) magnetic model of turbulence is a useful model for the magnetic field in the heliosphere. Normally, the diffusive behavior of charged particles in a turbulent magnetic field is observed when they approach the long time limit. The charged particles are often assumed to follow and diffuse according to the random walk of the field lines but some theories of perpendicular particle transport, such as nonlinear guiding center theory (NLGC), implicitly assume some true cross-field diffusion in which particles separate from the field line connected to their initial location. Furthermore, such cross-field diffusion is of specific interest because it is the only way that particles can diffuse across boundaries of magnetic field topology, such as the heliospheric current sheet and boundaries of interplanetary magnetic flux ropes. In this work, we study such cross-field diffusion using numerical techniques to simulate the trajectories of charged particles and magnetic field lines in two-component magnetic turbulence and to find the separation between the particles and their initial magnetic field lines. The guiding centers (GC) of the particles are computed here. Then we calculate the spreading between the GC of the particles and the trajectories of the field lines. We found that, in the pure slab turbulence, the particles stick with the magnetic field lines at which they initially start. In the 2D+slab case, the particles initially follow their initial field lines and then spread diffusively in the long time limit. We perform simulations for varying particle energy, ratio of 2D to slab fluctuations, and strength of the magnetic fluctuation in order to understand the relationship between the particle and magnetic field line trajectories. The diffusion coefficients of the particles have been calculated and compared with previous theories. This will lead to better understanding about the mechanisms of particle transport and will also help in developing a more complete transport theory of energetic charged particles in magnetic turbulence. Partially supported by the Thailand Research Fund, NSF SHINE ATM-0752135, and NASA Heliophysics Theory Program NNX08AI47G.

Chuychai, P.; Ruffolo, D. J.; Matthaeus, W. H.

2010-12-01

72

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%.

73

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

Energy Technology Data Exchange (ETDEWEB)

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.

Oka, T., E-mail: okat@eng.niigata-u.ac.jp [Niigata University, 8050 Ikarashi-Nino-Cho, Nishi-ku, Niigata 950-2181 (Japan); Seki, H.; Kimura, T.; Mimura, D.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M. [Niigata University, 8050 Ikarashi-Nino-Cho, Nishi-ku, Niigata 950-2181 (Japan); Fujishiro, H. [Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Hayashi, H. [Kyushu Electric Co., 2-1-47 Shiobaru, Minami-ku, Fukuoka 815-8520 (Japan); Yokoyama, K. [Ashikaga Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi 326-8558 (Japan); Stiehler, C. [IFW Dresden, Helmholzstr., 20-01069 Dresden (Germany)

2011-11-15

74

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

75

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

Science.gov (United States)

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

76

Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? The magnetic separation for Ni compounds was conducted by HTS bulk magnet. ? The coarse Ni-sulfate crystals were formed from the Ni-phosphite precipitates. ? Ni-sulfate crystals was separated from the mixture of Ni-sulfate and Ni-phosphite compounds. -- Abstract: The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45 T at 35 K in the static magnetic field of 5 T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow.

Oka, T., E-mail: okat@eng.niigata-u.ac.jp [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Fukazawa, H.; Fukui, S.; Ogawa, J.; Sato, T.; Ooizumi, M. [Niigata University, 8050 Ikarashi-Ninocho, Nishi-ku, Niigata 950-2181 (Japan); Tsujimura, M. [Aichi Giken Co., 50-1 Takeshita, Hitotugi-cho, Kariya, Aichi 448-0003 (Japan); Yokoyama, K. [Ashikaga Institute of Technology, 268-1 Ohmae-cho, Ashikaga, Tochigi 326-8558 (Japan)

2014-01-15

77

Collection of Ni-bearing material from electroless plating waste by magnetic separation with HTS bulk magnet  

International Nuclear Information System (INIS)

Highlights: ? The magnetic separation for Ni compounds was conducted by HTS bulk magnet. ? The coarse Ni-sulfate crystals were formed from the Ni-phosphite precipitates. ? Ni-sulfate crystals was separated from the mixture of Ni-sulfate and Ni-phosphite compounds. -- Abstract: The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45 T at 35 K in the static magnetic field of 5 T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow

78

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

79

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

DEFF Research Database (Denmark)

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

Smistrup, Kristian; Bu, Minqiang

2008-01-01

80

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

International Nuclear Information System (INIS)

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

81

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

82

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

International Nuclear Information System (INIS)

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

83

Drift magnetic separator for studies on the electron-positron pair production in laser plasma  

International Nuclear Information System (INIS)

Problems are considered which are related with the observation of the effect of the electron-positron pair generation in laser plasma. A simple method is suggested for recording of single positrons against the background of other particles emitted by the plasma. The method consists in the use of a magnetic device incorporating a linear conductor with current (a drift magnetic separator). A principle of operation and design are described, results are presented of tests of the developed drift magnetic separator

84

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.)

85

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

International Nuclear Information System (INIS)

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

86

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

Science.gov (United States)

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

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

2011-06-01

87

Cleaning of liquid radioactive waste by the methods of ozonization and magnetic separation  

International Nuclear Information System (INIS)

The possibility for purification of liquid radioactive wastes (LRW) from organic compounds by the methods of ozonization and magnetic separation is studied. It is shown that addition of a finely divided ferromagnetic substance into LRW and subsequent filtration through a magnetic filter is an effective method for removal of emulsified organic compounds. The dissolved organic compounds are destroyed by ozonization. Some characteristics of the ozonization and magnetic separation processes are determined. The composition of the products of reactions between ozone and organic compounds is defined. The behavior of 137Cs in the process of magnetic separation is investigated. A feasibility of very good cleaning of LRW from emulsified organic compounds by means of successive application of the methods of magnetic separation and ozonization is confirmed

88

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

Science.gov (United States)

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

Alp, Ibrahim

2008-10-01

89

Positive selection of human blood cells using improved high gradient magnetic separation filters.  

Science.gov (United States)

High gradient magnetic separators (HGMS) create magnetic field gradients that can be used to attract much smaller and less magnetic particles than those required for conventional magnetic separation techniques. As a result cells can be labeled with submicron magnetic particles and still be separated using an HGMS filter. Typically, HGMS filters consist of random arrays of wire such as stainless steel wool. Wire elements arranged regularly in a filter should allow more efficient separation of cells. Filters were constructed containing ordered wire arrays composed of 430 series stainless steel wire mesh with wire diameters of 50, 100, or 150 microns. The ability of these filters to separate T cells from peripheral blood mononuclear cell suspensions was tested and found superior to random arrays of 302 series stainless steel wire (Thomas et al, 1992). Target cells recognized by OKT5 monoclonal antibody were cross-linked to dextran-iron particles of approximately 20 nm in diameter. Separation conditions were optimized and after one passage through the filter 88% of the OKT5+ cells were recovered in the enriched fraction with 85% purity (%OKT5+). Multiple passages (3 times) could achieve 99% purity with 68% recovery. Variations in separation flow rate had a large effect on the balance between purity and recovery. Optimum separation efficiencies were achieved only when > 10(8) cells were processed. The primarily cause of nonspecific entrapment of CD8- cells was not nonspecific magnetic labeling of cells but the physical (nonmagnetic) characteristics of the filter/filter chamber. PMID:7522884

Thomas, T E; Richards, A J; Roath, O S; Watson, J H; Smith, R J; Lansdorp, P M

1993-01-01

90

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

Science.gov (United States)

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

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

2013-12-01

91

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

92

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-12-16

93

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

International Nuclear Information System (INIS)

This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.007832 =1.4058) in comparison with other samples

94

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

International Nuclear Information System (INIS)

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

95

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-04-15

96

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

97

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

Science.gov (United States)

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

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

2002-05-01

98

Optimum shell separation for closed axial cylindrical magnetic shields  

Science.gov (United States)

The effect of shell separation on the axial shielding with closed double-shell cylindrical shields is investigated numerically. It is found that the optimum shell separation for practical, equal-thickness shields of the above type is considerably smaller than that for transverse spherical and infinitely long cylindrical shields: in most cases, air gaps equal 5%-10% of the inner shell diameter are wide enough to bring the shielding to 90% of its maximum. This indicates that closely spaced axial shields can be used without much sacrifice in performance. Taking into account the computed optimum shell separation for double-shell shields, one can easily optimize and design a compact and effective multishell shield. Based on the numerical study, an analytical approximation is suggested for the axial shielding with narrowly spaced double-shell cylindrical shields.

Paperno, Eugene; Peliwal, Saee; Romalis, Michael V.; Plotkin, Anton

2005-05-01

99

Quantifying of magnetically separated particles using Hall-effect sensing  

Science.gov (United States)

In this paper, we present a modeling of a captured ferromagnetic particles quantifying method based on the detection and evaluation of the magnetic field variation caused by the particle static buildup. The detecting element is a Hall-effect sensor (probe) associated to the particle capture element which is an electromagnet with iron core. From a known value of the magnetic field measured at the particle static buildup locality, we predict the particle global concentration in the treated material sample (powder or liquid). This prediction is achieved by solving the inverse problem for the captured particles magnetic field variation. Such a resolution is based on an iterative resolution of the forward problem until obtaining the global particle concentration related to the measured value of the field variation. Because an exact value can not be obtained we retain the value that minimizes an error function. To minimize such a function we have used the Tabu searching method.

Mehasni, R.; Latreche, M. E.; Feliachi, M.

2007-08-01

100

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

101

A study on separation method of radioactive materials using superconducting magnetic technique  

International Nuclear Information System (INIS)

Research on superconducting magnetic separation method is being carried out in view of applying to nuclear fuel cycle technique with least emission of high-level radioactive wastes. After conceptual study on superconducting magnets and magnetic filters, the present authors constructed a component which can be employed in the experimental setup. This was to study separation mechanism and to evaluate the feasibility of gradient magnetic separation of powders of varying size (0.5 - 2 ?m) composed of Eu2O3, NiO and CeO2. The magnetic filter was made of SUS 430 and covar (Ni 29%, Co 17%, Fe 8%) and examined using electrostatic corrosion test. The mixed powders suspended in water were passed through the filter above mentioned repetitively and the effluent were analyzed for obtained mutual-separation efficiency as a function of applied magnetic field strength and repetition time. Computer simulation was also done to clarify the phenomenon leading to mutual separation which may called magnetic chromatography. (S. Ohno)

102

Parametric instabilities with well separated frequencies in magnetized plasmas  

International Nuclear Information System (INIS)

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

103

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

International Nuclear Information System (INIS)

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

104

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

International Nuclear Information System (INIS)

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

105

Separation of magnetic beads in a microfluidic device - Modeling and experimentation  

OpenAIRE

We describe a microfluidic system that uses a magnetic field to deflect paramagnetic beads in the direction normal to the flow. Through modeling and experimentation, we study this system to separate beads by their magnetic properties and size. We also use a similar system to move the beads from one fluid stream to an adjacent miscible stream. Copyright © 2011 by ASME.

Tsai, Ssh; Wexler, Js; Griffiths, Im; Stone, Ha

2011-01-01

106

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

Directory of Open Access Journals (Sweden)

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

A.V. Sandulyak

2013-04-01

107

Separation and acceleration of analogues of magnetic monopoles in semiconductor microcavities  

CERN Document Server

Half-integer topological defects in polariton condensates can be regarded as magnetic charges, with respect to built-in effective magnetic fields present in microcavities. We show how an integer topological defect can be separated into a pair of half-integer ones, paving the way towards flows of magnetic charges: spin currents or magnetricity. We discuss the corresponding experimental implementation within microwires (with half-solitons) and planar microcavities (with half-vortices).

Flayac, H; Malpuech, G

2012-01-01

108

Quantitative analysis of Si mass transport during formation of Cu/Si(111)-(5×5) from scanning tunneling microscopy  

Science.gov (United States)

The Si mass transport taking place during the formation of the Cu/Si(111)-(5×5) surface phase has been studied using scanning tunneling microscopy. From the measurement of the areas occupied by various structural domains and the quantitative consideration of the Si mass balance, the top Si atom density in the Cu/Si(111)-(5×5) phase is found to be 0.96 monolayer. The Cu/Si(111)-(5×5) structure is suggested to consist of a planar CuSi overlayer with an atomic ratio of Cu:Si close to 1:1. Further Cu deposition beyond the formation of Cu/Si(111)-(5×5) phase results in the formation of Cu nanocrystals on the intermediate (5×5) layer.

Zhang, Y. P.; Yong, K. S.; Chan, H. S. O.; Xu, G. Q.; Chen, S.; Wang, X. S.; Wee, A. T. S.

2007-02-01

109

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

Science.gov (United States)

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

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

2010-03-01

110

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.

111

Magnetic Resonance Spectrum Separation Using Sparse Representations and Wavelet Filters  

OpenAIRE

Magnetic Resonance spectroscopy (MRS) provides a “frequency-signal intensity” spectrum of multiple peaks that reflect the biochemical composition of a localized region in the body. The peak intensity or the area under each peak is proportional to the concentration of that assigned metabolite. Accurate quantification of in vivo MRS (measuring peak intensity or area) is very important to diagnose certain metabolic disorders. However, strongly overlapping metabolite peaks, poor knowledge abo...

Guo, Yu; Ruan, Su; Landre?, Je?ro?me; Constants, Jean-marc

2009-01-01

112

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

113

SASSY, a gas-filled magnetic separator for the study of fusion reaction products  

International Nuclear Information System (INIS)

A gas-filled on-line recoil separator at the Berkeley SuperHILAC is described. The separator consists of a magnetic dipole and a quadrupole doublet. The system is filled with He at a pressure of about 1 Torr (? 130 Pa). It separates particles according to their average magnetic rigidity. This allows a separation of evaporation residues, scattered target atoms and beam projectiles in a nuclear reaction. The separation time is in the order of 10-6 s; the transmission is about 50% for evaporation residues, less than 10-3 for scattered target-like recoil ions and transfer products, and about 10-15 for full energy beam projectiles. Experimental data over a wide range of reactions are given and it is shown that the average charge of the recoils is determined by the atomic shell structure of the moving ionized atom in the gas. (orig.)

114

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

Science.gov (United States)

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

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

2014-12-01

115

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

116

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

Science.gov (United States)

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

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

2001-01-01

117

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

DEFF Research Database (Denmark)

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

Hubbuch, Jürgen; Matthiesen, D.B.

2001-01-01

118

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

119

Laser isotope separation of barium using an inhomogeneous magnetic field  

Science.gov (United States)

A barium atomic beam undergoes selective isotopic excitation by a dye laser to the 1P1 state. This state radiatively decays back to the ground state or to the (6s5d)D states, which are deflected out of the beam by an inhomogeneous magnetic field. The residual atomic beam is examined by a quadrupole mass spectrometer, and isotopic depletions of up to 60% are obtained using laser powers of a few hundred milliwatts. The isotopic splitting of the 1S0-->1P1 transitions for 136Ba and the F=5/2 states of 135,137Ba are measured relative to that for 138Ba and agree well with those found previously.

van Wijngaarden, W. A.; Li, J.

1994-02-01

120

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

Science.gov (United States)

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

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

2014-07-01

121

Wide aperture multipole magnets of the kinematic separator COMBAS. Analyzing multipole magnets M2 and M7 with compensation for higher order aberrations  

International Nuclear Information System (INIS)

The high-resolving large aperture kinematic separator COMBAS has been created and commissioned. The magneto-optical structure of separator is based on the strong focusing principle. The separator consists of eight wide aperture multipole magnets M1-M8. In part, the separator includes bending multipole magnets M2 and M7 having quadrupole, sextupole and octupole components in their field distributions. The presence of these components allowed one to intensify focusing without separate quadrupoles, minimize spherical aberrations and compensate for chromatic effects. Three-component magnetic field measurements on the surface of a closed volume have been performed for the magnets M2 and M7. These measurements allowed one to analyze the magnet manufacturing quality. The measured data will allow one to compile 3D-maps of magnetic fields. The 3D-maps of the magnetic field are supposed to be used for the particle trajectory simulations throughout the separator

122

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)

123

On the use of magnetic separation for purification of aqueous radioactive solutions from oils  

International Nuclear Information System (INIS)

Using model systems, simulating oiled condensate that is formed during evaporation of water radioactive wastes, a possibility is shown to use the method of magnetic separation for waste purification from oil. Introduction of a dispersed ferromagnetic powder in the system to stabilize oil drops and to impart ''quasiferromagnetic'' properties to them, is a necessary condition for the efficient oil separation. Using as an example 137Cs absorption, the adsorbability of ferromagnetic powders relative to radionuclides in the system investigated is assessed

124

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

OpenAIRE

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-inerti...

Ahedo Galilea, Eduardo; Merino, Mario

2012-01-01

125

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

Science.gov (United States)

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

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

2013-09-01

126

Magnetic separation as an adjunct to surface barrier detectors for backscattering and ion reaction analysis methods  

International Nuclear Information System (INIS)

The sensitivity of analysis by energy spectroscopy of product ions using solid state detectors is often limited by instrumental background from pulse pileup, due to an intense flux of lower energy ions scattered from the accelerator beam. A small magnet can be used for low resolution separation of ions of different type and/or energy. In the present work a simple permanent magnet is used to reject ions of low magnetic rigidity. The technique has been developed for the depth profiling of oxygen in solar absorber surfaces using the 18O(p,?) reaction, and to determine surface trces of gold on silicon substrates

127

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.

128

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

129

Magnetic characteristics of phase-separated CeO2:Co thin films  

Science.gov (United States)

Herewith, we are reporting the magnetic properties of phase-separated Co-doped CeO2 films (with a Ce:Co atomic-ratio of 0.97:0.03) grown on single-crystal SrTiO3 (001) substrates. A comparison of the magnetic characteristics of these films with those of homogenously doped CeO2:Co films of the same composition illustrates the significant differences in their magnetic behavior. These behavioral characteristics provide a model for determining if the magnetic behavior observed in this, as well as in other diluted magnetic dielectric systems, is due to homogeneous doping, a mixture of doping and transition metal cluster formation, or exists purely as a result of transition metal clustering.

Prestgard, M. C.; Siegel, G.; Ma, Q.; Tiwari, A.

2013-09-01

130

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

International Nuclear Information System (INIS)

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

131

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

Science.gov (United States)

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

Ahedo, Eduardo; Merino, Mario

2012-08-01

132

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-15

133

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

134

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

135

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

136

Desulphurisation of coal pyrolysis and magnetic separation. Desulfuracion de carbones mediante pirolisis y separacion magnetica  

Energy Technology Data Exchange (ETDEWEB)

The desulphurisation of coal intended for use inthermal power stations is a priority issue in the national strategy for the reduction of acid rain. This article studies the feasibility of eliminating pyritic sulphur from coal by physical methods using high intensity pyrolysis and magnetic separation. 6 refs., 9 figs., 4 tabs.

Ruiz, J.C.; Ayala, N.; Ibarra, J.V.; Moliner, R.; Miranda, J.L.; Vazquez, A. (CENIM, Madrid (Spain))

1991-07-01

137

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

International Nuclear Information System (INIS)

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

138

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

Science.gov (United States)

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

Madhavan, N.; Das, J. J.; Sugathan, P.; Kataria, D. O.; Avasthi, D. K.; Mandal, A.; Sinha, A. K.

1996-02-01

139

Simulation of the Probe Formation Processes in the Separated Systems of Magnetic Quadrupole Lenses  

Directory of Open Access Journals (Sweden)

Full Text Available A numerical scheme for simulation of the particles transport thru the probe-forming system with an angle displacement of the magnetic quadrupole lenses from normal position was developed. An effect of each lens displacement for microprobe parameters in separated probe-forming systems for both widespread configurations – triplet and Russian Quadruplet was studied.

S.V. Kolinko

2012-10-01

140

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

141

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)

142

Preparation and characterization of chemically functionalized silica-coated magnetic nanoparticles as a DNA separator.  

Science.gov (United States)

The work describes a simple and convenient process for highly efficient and direct DNA separation with functionalized silica-coated magnetic nanoparticles. Iron oxide magnetic nanoparticles and silica-coated magnetic nanoparticles were prepared uniformly, and the silica coating thickness could be easily controlled in a range from 10 to 50 nm by changing the concentration of silica precursor (TEOS) including controlled magnetic strength and particle size. A change in the surface modification on the nanoparticles was introduced by aminosilanization to enhance the selective DNA separation resulting from electrostatic interaction. The efficiency of the DNA separation was explored via the function of the amino-group numbers, particle size, the amount of the nanoparticles used, and the concentration of NaCl salt. The DNA adsorption yields were high in terms of the amount of triamino-functionalized nanoparticles used, and the average particle size was 25 nm. The adsorption efficiency of aminofunctionalized nanoparticles was the 4-5 times (80-100%) higher compared to silica-coated nanoparticles only (10-20%). DNA desorption efficiency showed an optimum level of over 0.7 M of the NaCl concentration. To elucidate the agglomeration of nanoparticles after electrostatic DNA binding, the Guinier plots were calculated from small-angle X-ray diffractions in a comparison of the results of energy diffraction TEM and confocal laser scanning microscopy. Additionally, the direct separation of human genomic DNA was achieved from human saliva and whole blood with high efficiency. PMID:19099431

Kang, Kiho; Choi, Jinsub; Nam, Joong Hee; Lee, Sang Cheon; Kim, Kyung Ja; Lee, Sang-Won; Chang, Jeong Ho

2009-01-15

143

Magnetic separation of Dy(III) ions from homogeneous aqueous solutions  

Science.gov (United States)

The possibility to enrich paramagnetic dysprosium(III) ions in a magnetic field gradient is proved by means of interferometry, which may open the route for a magnetic separation of rare earth ions from aqueous solutions. The separation dynamics are studied for three different concentrations of DyCl3 and compared with those found recently in a sulphate solution of the 3d ion Mn(II). In view of the similar-sized hydration spheres for Dy(III) and Mn(II), the slower separation dynamics in DyCl3 is attributed to both a higher densification coefficient and the strong impact of Brownian motion due to the absence of ion-pair clusters.

Pulko, B.; Yang, X.; Lei, Z.; Odenbach, S.; Eckert, K.

2014-12-01

144

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

145

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.

146

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

International Nuclear Information System (INIS)

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

147

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

148

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

International Nuclear Information System (INIS)

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

149

A comprehensive in vitro investigation of a portable magnetic separator device for human blood detoxification  

International Nuclear Information System (INIS)

A portable magnetic separator device is being developed for a proposed magnetically based detoxification system. In this paper, the performance of this device was evaluated via preliminary in vitro flow experiments using simple fluids and a separator unit consisting of one tube and two metal wires, each at the top and bottom of the tube. The effects of the following factors were observed: mean flow velocity Uo (0.14-45 cm s-1), magnetic field strength ?oHo (0.125-0.50 T), wire size Rw (0.125, 0.250 and 0.500 mm), wire length Lw (2, 5 and 10 cm), wire materials (nickel, stainless steel 304 and 430) and tube size (outer radius Ro = 0.30 mm and inner radius Ri = 0.25 mm; Ro = 0.50 mm and Ri = 0.375 mm; and Ro = 2.0 mm and Ri = 1.0 mm). Our observations showed that the experimental results fit well with the corresponding theoretical results from the model we previously developed at a low flow velocity area (for example, Uo ? 20 cm s-1), strong external magnetic field (for example, ?0.30 T) and long wire length (for example, Lw = 10 cm). The experimental results also showed that more than 90% capture efficiency is indeed achievable under moderate systemic and operational conditions. Pressure drop measurements revealed that the device could work well under human physiological and clinical conditions, and spgical and clinical conditions, and sphere buildup would not have any considerable effect on the pressure drop of the device. The breakthrough experiments demonstrated that a lower flow rate V, higher applied magnetic field ?oHo and diluted sphere suspension, i.e. lower Co, would delay the breakthrough. All the results indicate the promise of this portable magnetic separator device to efficiently in vivo sequestrate nano-/micro-spheres from blood flow in the future magnetically based detoxification system

150

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

151

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

Science.gov (United States)

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

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

2008-01-01

152

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

Energy Technology Data Exchange (ETDEWEB)

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

Kaur, Maninder; Johnson, Andrew; Tian, Guoxin; Jiang, Weilin; Rao, Linfeng; Paszczynski, Andrzej; Qiang, You

2013-01-15

153

Separating Effect of a Novel Combined Magnetic Field on Inclusions in Molten Aluminum Alloy  

Science.gov (United States)

The feasibility and effectiveness of a novel combined magnetic field (CMF) on the removal of inclusions with a density smaller than the surrounding melt were investigated. The experiment of the separating effect of CMF was conducted on a laboratory-scale apparatus by the simultaneous application of a rotating magnetic field (RMF) and a downward traveling magnetic field (TMF). Primary silicon particles precipitating from the solidification process of Al-Si-Cu alloy were regarded as the inclusions in a molten aluminum alloy. It was found that a CMF consisting of both a RMF and a downward TMF was able to separate silicon particles from the molten Al-Si-Cu alloy by making these particles migrate vertically toward the upper part of the samples. Compared with downward TMF or RMF, CMF improved the separating effectiveness substantially. It was proposed that this type of CMF was approved to be highly effective at eliminating the inclusions with a density smaller than the surrounding molten alloy. A tentative mechanism for the high separating effect of CMF was discussed.

He, Yanjie; Li, Qiulin; Liu, Wei

2012-10-01

154

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.)

155

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

International Nuclear Information System (INIS)

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

156

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

157

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-10-01

158

Combined performance of biochar sorption and magnetic separation processes for treatment of chromium-contained electroplating wastewater.  

Science.gov (United States)

Magnetic biochar was prepared with eucalyptus leaf residue remained after essential oil being extracted. Batch experiments were conducted to examine the capacity of the magnetic biochar to remove Cr (VI) from electroplating wastewater and to be separated by an external magnetic field. The results show that the initial solution pH plays an important role on both sorption and separation. The removal rates of Cr (VI), total Cr, Cu (II), and Ni (II) were 97.11%, 97.63%, 100% and 100%, respectively. The turbidity of the sorption-treated solution was reduced to 21.8NTU from 4075NTU after 10min magnetic separation. The study also confirms that the magnetic biochar still retains the original magnetic separation performance after the sorption process. PMID:25463783

Wang, Sheng-Ye; Tang, Yan-Kui; Li, Kun; Mo, Ya-Yuan; Li, Hao-Feng; Gu, Zhan-Qi

2014-10-01

159

High-gradient magnetic separation for the treatment of high-level radioactive wastes  

International Nuclear Information System (INIS)

Argonne National Laboratory is developing an open-gradient magnetic separation (OGMS) system to fractionate and remove nonglass-forming species from high-level radioactive wastes (HLW); however, to avoid clogging, OGMS may require high-gradient magnetic separation (HGMS) as a pretreatment to remove the most magnetic species from the HLW. In this study, the feasibility of using HGMS in the pretreatment of HLW was demonstrated. A HLW simulant of hanford's C-103 tank waste, which contained precipitate hydroxides and oxides of Fe, Al, Si, and Ca, was used. Preliminary fractionation results from a 0.3-T bench-scale HGMS unit showed that a significant amount of Fe could be removed from the HLW simulant. Between 1 and 2% of the total Fe in the sludge was removed during each stage, with over 18.5% removed in the 13 stages that were carried out. Also, in each stage, the magnetically retained fraction contained about 20% more Fe than the untreated HLW; however, it also contained a significant amount of SiO2 in relatively large particles. This indicated that SiO2 was acting possibly as a nucleation agent for Fe (i.e., an Fe adsorbent) and that the fractionation was based more on size than on magnetic susceptibility

160

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

Energy Technology Data Exchange (ETDEWEB)

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

Odenthal, J.; Ziemann, W.

1981-01-01

161

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

Science.gov (United States)

Electrons have an intrinsic, indivisible, magnetic dipole aligned with their internal angular momentum (spin). The magnetic interaction between two electronic spins can therefore impose a change in their orientation. Similar dipolar magnetic interactions exist between other spin systems and have been studied experimentally. Examples include the interaction between an electron and its nucleus and the interaction between several multi-electron spin complexes. The challenge in observing such interactions for two electrons is twofold. First, at the atomic scale, where the coupling is relatively large, it is often dominated by the much larger Coulomb exchange counterpart. Second, on scales that are substantially larger than the atomic, the magnetic coupling is very weak and can be well below the ambient magnetic noise. Here we report the measurement of the magnetic interaction between the two ground-state spin-1/2 valence electrons of two (88)Sr(+) ions, co-trapped in an electric Paul trap. We varied the ion separation, d, between 2.18 and 2.76 micrometres and measured the electrons' weak, millihertz-scale, magnetic interaction as a function of distance, in the presence of magnetic noise that was six orders of magnitude larger than the magnetic fields the electrons apply on each other. The cooperative spin dynamics was kept coherent for 15 seconds, during which spin entanglement was generated, as verified by a negative measured value of -0.16 for the swap entanglement witness. The sensitivity necessary for this measurement was provided by restricting the spin evolution to a decoherence-free subspace that is immune to collective magnetic field noise. Our measurements show a d(-3.0(4)) distance dependence for the coupling, consistent with the inverse-cube law. PMID:24943952

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

2014-06-19

162

Interplay between mesoscopic phase separation and bulk magnetism in the layered NaxCoO2  

OpenAIRE

Specific heat of the layered NaxCoO2 (x=0.65, 0.70 and 0.75) oxides has been measured in the temperature range of 3-360 K and magnetic field of 0 and 9 T. The analysis of data, assuming the combined effect of inter-layer superexchange and the phase separation into mesoscopic magnetic domains with localized spins embedded in a matrix with itinerant electronic character, suggests that the dominant contribution to the specific heat in the region of short-range ordering is media...

Zorkovska, A.; Orendac, M.; Sebek, J.; Santava, E.; Svoboda, P.; Bradaric, I.; Savic, I.; Feher, A.

2005-01-01

163

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

International Nuclear Information System (INIS)

Tilted foil polarization and on-line mass separation have been successfully applied to a ?-NMR technique for measuring nuclear moments. Nuclei are polarized using tilted carbon foils (multifoil array) and implanted in a catcher. Nuclear polarization, monitored by detection of anisotropic ?-emission, is destroyed via resonant rf excitation to locate the NMR. Tests were performed using 12B (T1/2 = 20.4 ms, I? = 1+) and the ground-state magnetic moment of 33Cl (T1/2 = 2.51 s, I? = 3/2+) was measured using this arrangement. The 33Cl magnetic moment, corrected for diamagnetism, is ? = +0.7523(16) nm. (orig.)

164

Purification of molybdenum powders salts and oxides by the magnetic separation method  

International Nuclear Information System (INIS)

Purification results of MoO3 and MoO2 oxides and different production lot molybdenum powder using high-grade magnetic separation technique are given. Inclusions containing iron and silicon are determined to be removed most efficiently. On an average, half of magnetic fraction consists of such inclusions, the rest represents inclusions bearing aluminium, calcium, magnesium, titanium etc. Quartz, iron-containing minerals, calcites, feldspar, titanomagnetite, detected in ammonium paramolybdate and representing most typical inclusions occur in molybdenum oxides and powders with prevalence of quartz and iron-base inclusions

165

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

166

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

167

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

168

Fermi Surface Reconstruction by Dynamic Magnetic Fluctuations and Spin-Charge Separation Near an O(3) Quantum Critical Point  

OpenAIRE

Stimulated by the small/large Fermi surface controversy in the cuprates we consider a small number of holes injected into the bilayer antiferromagnet. The system has an O(3) quantum critical point (QCP) separating the magnetically ordered and the magnetically disordered phases. We demonstrate that nearly critical quantum magnetic fluctuations can change the Fermi surface topology and also lead to spin charge separation (SCS) in two dimensions. We demonstrate that in the phys...

Holt, Michael; Oitmaa, Jaan; Chen, Wei; Sushkov, Oleg P.

2012-01-01

169

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

170

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

171

Local magneto-electric effects from separate areas of magnetic domains of yttrium iron garnets  

Energy Technology Data Exchange (ETDEWEB)

Magneto-electric properties (electromagneto-optical effect (EMOE)) of separate magnetic domains of yttrium iron garnets (YIGs) are investigated with using an optical polarimetry method. This local effect depends on the chosen point of optical scanning and changes essentially at scanning of various points of the domain. We have revealed separate sites of YIG sample where sharp changes of the electromagneto-optical (EMO) signal concerning average value in the domain are registered. We assume that the defect area (or its vicinity) on a surface or in volume of the investigated YIG sample causes the specified changes of EMO effect value. When probing by thin laser beam various sites of the magnetic domain, it is possible to define the defects positions by EMO signal value and it can matter for applications. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Koronovskyy, Vadim; Gorchinskii, Nikolai [Department of Radiophysics, Taras Shevchenko Kiev National University, 2, Prospekt Glushkova Street, 03127 Kiev (Ukraine)

2011-12-15

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

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

Science.gov (United States)

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

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

2011-11-01

174

Magnetic Domain Walls in Single-Phase and Phase-Separated Double Exchange Systems  

OpenAIRE

We investigate the structure of magnetic domain walls in a classical double exchange ferromagnet, evaluating domain wall energies and charges. Three different cases are studied: (i) a conventional smooth Bloch wall, (ii) an abrupt Ising-type wall, which is shown to have lower energy at small values of carrier concentration, and (iii) stripe wall, corresponding to the two ferromagnetic domains being separated by a stripe of another, antiferromagnetic, phase. General aspects o...

Golosov, D. I.

2002-01-01

175

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

International Nuclear Information System (INIS)

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

176

SERS-fluorescence joint spectral encoded magnetic nanoprobes for multiplex cancer cell separation.  

Science.gov (United States)

A new kind of cancer cell separation method is demonstrated, using surface-enhanced Raman scattering (SERS) and fluorescence dual-encoded magnetic nanoprobes. The designed nanoprobes can realize SERS-fluorescence joint spectral encoding (SFJSE) and greatly improve the multiplexing ability. The nanoprobes have four main components, that is, the magnetic core, SERS generator, fluorescent agent, and targeting antibody. These components are assembled with a multi-layered structure to form the nanoprobes. Specifically, silica-coated magnetic nanobeads (MBs) are used as the inner core. Au core-Ag shell nanorods (Au@Ag NRs) are employed as the SERS generators and attached on the silica-coated MBs. After burying these Au@Ag NRs with another silica layer, CdTe quantum dots (QDs), that is, the fluorescent agent, are anchored onto the silica layer. Finally, antibodies are covalently linked to CdTe QDs. SFJSE is fulfilled by using different Raman molecules and QDs with different emission wavelengths. By utilizing four human cancer cell lines and one normal cell line as the model cells, the nanoprobes can specifically and simultaneously separate target cancer cells from the normal ones. This SFJSE-based method greatly facilitates the multiplex, rapid, and accurate cancer cell separation, and has a prosperous potential in high-throughput analysis and cancer diagnosis. PMID:24862088

Wang, Zhuyuan; Zong, Shenfei; Chen, Hui; Wang, Chunlei; Xu, Shuhong; Cui, Yiping

2014-11-01

177

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

178

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

International Nuclear Information System (INIS)

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

179

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

180

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-11-01

181

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.

182

Core-shell magnetic nanoparticles: a comparative study based on silica and polydopamine coating for magnetic bio-separation platforms.  

Science.gov (United States)

Core-shell magnetic nanoparticles (MNPs) offer tremendous opportunities in a large range of applications in biomedicine due to their superior magnetic properties, biocompatibility and suitability for modification. In most cases, these characteristic features are determined by their shell chemistry and morphology. Herein, we demonstrate a comparative study of silica and polydopamine (PDOP) coating onto MNP surfaces based on synthesis, characterization and usage in a bio-separation platform. It was found that monodispersed MNPs may be easily obtained on silica coating of varying shell thickness, whereas a continuous PDOP layer observed around the MNPs prevents the formation of the dispersed form. On the other hand, PDOP coated MNPs exhibited better superparamagnetic behavior and biological modification ability compared to the silica coated form. PMID:23050265

Sahin, Ferat; Turan, Eylem; Tumturk, Hayrettin; Demirel, Gokhan

2012-12-01

183

Nanomagnetism of Core-Shell Magnetic Nanoparticles and Application in Spent Nuclear Fuel Separation  

Science.gov (United States)

This dissertation presents the study on novel core-shell magnetic nanoparticles (NPs) with unique magnetic properties. Understanding the fundamental physics of antiferromagnetic - ferromagnetic interactions is essential to apply in different applications. Chromium (Cr) doped and undoped core-shell iron/iron-oxide NPs have been synthesized using cluster deposition system and studied with respect to their nanostructures, morphologies, sizes, chemical composition and magnetic properties. The room-temperature magnetic properties of Fe based NPs shows the strong dependence of intra/inter-particle interaction on NP size. The Cr-doped Fe NP shows the origin of sigma-FeCr phase at very low Cr concentration (2 at.%) unlike others reported at high Cr content and interaction reversal from dipolar to exchange interaction. A theoretical model of watermelon is constructed based on the experimental results and core-shell NP system in order to explain the physics of exchange interaction in Cr-doped Fe particles. The magnetic nanoparticle---chelator separation nanotechnology is investigated for spent nuclear fuel recycling and is reported 97% and 80% of extraction for Am(III) and Pu(IV) actinides respectively. If the long-term heat generating actinides such as Am(III) 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. As it is a simple, versatile, compact, and cost efficient process that minimizes secondary waste and improves storage performance.

Tarsem Singh, Maninder Kaur

184

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.

185

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

International Nuclear Information System (INIS)

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

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

Separation and measurement of silver nanoparticles and silver ions using magnetic particles.  

Science.gov (United States)

The recent surge in consumer products and applications using metallic nanoparticles has increased the possibility of human or ecosystem exposure due to unintentional release into the environment. To protect consumer health and the environment, there is an urgent need to develop tools that can characterize and quantify these materials at low concentrations and in complex matrices. In this study, magnetic nanoparticles coated with either dopamine or glutathione were used to develop a new, simple and reliable method for the separation/pre-concentration of trace amounts of silver nanoparticles followed by their quantification using inductively coupled plasma mass spectrometry (ICP-MS). The structurally modified magnetic particles were able to capture trace amounts of silver nanoparticles (~2 ppb) and concentrate (up to 250 times) the particles for analysis with ICP-MS. Under laboratory conditions, recovery of silver nanoparticles was >99%. More importantly, the magnetic particles selectively captured silver nanoparticles in a mixture containing both nano-particulate and ionic silver. This unique feature addresses the challenges of separation and quantification of silver nanoparticles in addition to the total silver in environmental samples. Spiking experiments showed recoveries higher than 97% for tap water and both fresh and saline surface water. PMID:24295749

Mwilu, Samuel K; Siska, Emily; Baig, R B Nasir; Varma, Rajender S; Heithmar, Ed; Rogers, Kim R

2014-02-15

188

Setup of a separator magnet and an RFQ-buncher for the TRIGA-SPEC experiment  

International Nuclear Information System (INIS)

Precise experimental data of the ground-state properties of heavy nuclides are required to test the predictive power of nuclear mass models and to support nucleosythesis calculations of the astrophysical r-process. The TRIGA-TRAP mass spectrometer and the TRIGA-LASER laser spectroscopy setup, forming the TRIGA-SPEC experiment, were recently installed at the research reactor TRIGA Mainz in order to perform high-precision measurements of the ground state properties of short-lived neutron-rich radionuclides. The radionuclides are produced by thermal neutron-induced fission in an actinoide target inside the reactor, extracted by a gas-jet system, and ionized by an ECR ion source. The ions of interest will then be mass-separated in a 90 dipole magnet. An RFQ buncher is being installed to accumulate, cool and bunch the ion beam. The status of the implementation of the dipole magnet and the RFQ buncher is presented.

189

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

International Nuclear Information System (INIS)

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

190

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

191

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

Science.gov (United States)

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

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

2004-07-01

192

Separation of Selenite from Inorganic Selenium Ions using TiO{sub 2} Magnetic Nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

A simple and quick separation technique for selenite in natural water was developed using TiO{sub 2} SiO{sub 2}/Fe{sub 3}O{sub 4} 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 TiO{sub 2} shell. The synthesized nanoparticles were used to separate selenite (Se{sup 4+}) in the presence of Se{sup 6+} or selenium anions for the photocatalytic reduction to Se{sup 0} atom on the TiO{sub 2} shell, followed by magnetic separation using Fe{sub 3}O{sub 4} 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.

Kim, Jongmin; Lim, H. B. [Donkook Univ., Yongin (Korea, Republic of)

2013-11-15

193

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

Science.gov (United States)

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

Kusakabe, Motohiko; Kawasaki, Masahiro

2015-01-01

194

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

195

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

196

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

197

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

International Nuclear Information System (INIS)

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

198

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

Science.gov (United States)

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

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

1999-01-01

199

Magnetic separation of amino acids by gold/iron-oxide composite nanoparticles synthesized by gamma-ray irradiation  

Energy Technology Data Exchange (ETDEWEB)

Amounts of amino acids adsorbed onto the Au/{gamma}-Fe{sub 2}O{sub 3} composite nanoparticles synthesized by gamma-ray irradiation were measured using magnetic separation technique. Cystine and methionine, which are sulfur-containing amino acids, connected to Au by a Au-S bond could be selectively picked up by a magnet.

Kinoshita, Takuya [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)]. E-mail: t-kinoshita@stu.nucl.eng.osaka-u.ac.jp; Seino, Satoshi [Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Mizukoshi, Yoshiteru [Osaka Prefectural College of Technology, Neyagawa, Osaka 572-8572 (Japan); Otome, Yohei [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nakagawa, Takashi [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Okitsu, Kenji [Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Yamamoto, Takao A. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2005-05-15

200

Magnetic separation of amino acids by gold/iron-oxide composite nanoparticles synthesized by gamma-ray irradiation  

International Nuclear Information System (INIS)

Amounts of amino acids adsorbed onto the Au/?-Fe2O3 composite nanoparticles synthesized by gamma-ray irradiation were measured using magnetic separation technique. Cystine and methionine, which are sulfur-containing amino acids, connected to Au by a Au-S bond could be selectively picked up by a magnet

201

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

OpenAIRE

We present magnetization studies in a series of phase separated La$_{0.5}$Ca$%_{0.5}$MnO$_{3}$ samples, with different low temperature fractions of the ferromagnetic (FM) and charge ordered-antiferromagnetic (CO-AFM) phases. A particular experimental procedure probes the effect of the magnetic field applied while cooling the samples, which promotes FM fraction enlargement and enhances the melting of the CO phase. The response of the system depending on its magnetic field his...

Freitas, R. S.; Ghivelder, L.; Levy, P.; Parisi, F.

2001-01-01

202

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

203

Rapid detection of dengue virus in serum using magnetic separation and fluorescence detection.  

Science.gov (United States)

A magnetophoretic fluorescence sensor (MFS) has been developed to rapidly detect dengue virus in serum at a sensitivity that was approximately three orders of magnitude higher than conventional solid phase immunoassays. UV inactivated type 2 dengue virus was first reacted with a mixture of superparamagnetic and fluorescent microparticles functionalised with an anti-type 2 dengue virus monoclonal antibody in 10% fetal calf serum. The magnetic particles were separated from the serum based on their magnetophoretic mobility, and dengue virus was detected by the co-localization of magnetic and fluorescent particles at a specific point in the flow chamber. The MFS was capable of detecting dengue-2 virus at 10 PFU ml(-1) with a reaction time of 15 min. The MFS demonstrated a high specificity in the presence of yellow fever virus, a closely related flavivirus, which also did not produce any detectable increase in background signal. The improved performance of this technique appears to result from the rapid kinetics of the microparticle reaction, improved signal-to-noise ratio resulting from magnetophoretic separation, and rapid fluorescent particle detection. These results suggest that the MFS may be useful in early stage diagnosis of dengue infections, as well as other diseases. PMID:18227947

Chang, Won-Suk; Shang, Hao; Perera, Rushika M; Lok, Shee-Mei; Sedlak, Dagmar; Kuhn, Richard J; Lee, Gil U

2008-02-01

204

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

Science.gov (United States)

Teicoplanin-conjugated mesoporous silica magnetic nanoparticles (TE-MSMNPs) were fabricated as novel chiral magnetic nano-selectors. Successful preparation of the functional magnetic mesoporous materials was achieved by grafting teicoplanin on N-(2-aminoethyl)-3-aminopropyltrimethoxysilane-modified mesoporous silica Fe3O4 magnetic nanoparticles (AEAPTMS-MSMNPs), and this was confirmed by various characterization techniques. The synthesized magnetic nanoparticles were regularly spherical and uniformly mesoporous with an average diameter of around 600 nm and a mean pore size of about 3.9 nm, respectively. These versatile magnetic nanoparticles were effective in a direct chiral separation of five racemic compounds in phosphate buffer. Much stronger interactions were observed with the (+)-enantiomers than with the (-)-enantiomers. After washing with water and ethanol by sonication, TE-MSMNPs could be reused at least three times with little efficiency loss. The functional magnetic mesoporous nanoparticles were easily separated from the racemic solutions using an external magnetic field. These magnetic nano-materials are suitable for enantiomer separations. PMID:23541694

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

2013-06-01

205

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

Science.gov (United States)

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

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

2014-11-01

206

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

207

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

Energy Technology Data Exchange (ETDEWEB)

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.

Goncharov, A.A.; Datsko, N.I.; Soloshenko, I.A. [National Academy of Sciences of Ukraine, Kiev (Ukraine). Inst. of Physics

1995-12-01

208

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

Science.gov (United States)

We have developed a target-molecule-functionalized magnetic nanoparticle (MNP)-based method to facilitate the study of biomolecular recognition and separation. The superparamagnetic property of MNPs allows the corresponding biomolecules to be rapidly separated from crude biofluids with a significant improvement in recovery yield and specificity. Various MNPs functionalized with tag molecules (chitin, heparin, and amylose) were synthesized for recombinant protein purification, and several probe-functionalized MNPs, such as nitrilotriacetic acid (NTA)@MNP and P(k)@MNP, exhibited excellent extraction efficiency for proteins. In a cell recognition study, mannose-functionalized MNPs allowed specific purification of Escherichia coli with FimH adhesin on the surface. In an immunoprecipitation assay, the antibody-conjugated MNPs reduced the incubation time from 12 to 1 h while maintaining a comparable efficiency. The functionalized MNPs were also used in a membrane proteomic study that utilized the interaction between streptavidin-functionalized MNPs and biotinylated cell membrane proteins. Overall, the functionalized MNPs were demonstrated to be promising probes for the specific separation of targets from proteins to cells and proteomics. PMID:23198853

Lin, Po-Chiao; Yu, Ching-Ching; Wu, Huan-Ting; Lu, Ying-Wei; Han, Chia-Li; Su, An-Kai; Chen, Yu-Ju; Lin, Chun-Cheng

2013-01-14

209

Mass separation of a multi-component plasma flow travelling through a magnetic transport system  

Science.gov (United States)

The travel of plasma flow produced by a dc arc through a transport system based on a curved magnetic field was studied. The characteristics of the system were the absence of a curved metallic plasma guiding duct ('open architecture') and the fact that the magnetic field coils were non-coaxial to the plasma flow. By means of Langmuir probe measurements it was shown that both shape and position of the cathode plasma flow at the exit of the transport system were governed by variation of currents of the magnetic coils as well as by biasing of a special electrode inserted into the plasma flow. It was found that with parameters of the transport system held constant, the plasma ions with lower m/Z were deflected more, e.g. Al ions were deflected more than Ti ions. For an arc with a composite cathode, consisting of mainly Cr-Fe-Ni, the profile of atoms of these elements at the exit of the transport system was measured by x-ray fluorescence spectrometry. The results obtained were consistent with the probe measurements, hence the transport system, in principle, may be used for spatial separation of a multi-component (in masses) plasma flow.

Paperny, V. L.; Krasov, V. I.; Lebedev, N. V.; Astrakchantsev, N. V.

2011-06-01

210

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

211

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

212

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

International Nuclear Information System (INIS)

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

213

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

214

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-01-15

215

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.

216

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

217

The evaluation of thyrotropin immunoradiometric assay kit (magnetic separation) in clinical application  

International Nuclear Information System (INIS)

The average recovery of the thyrotropin immunoradiometric assay (TSH IRMA) is (104.8 +- 4.1)%. The coefficients of variation in intra-and inter assay are 9.0% and 15.4%, respectively. The average batch coefficient of variation is 0.0077-0.0216. The 95% confidence interval of serum TSH IRMA was 0.41-4.28 mIU/I in 45 blood donors. The levels of TSH in 113 cases with hyperthyroidism are below 0.41 mIU/l in IRMA, but normal in RIA. The levels of TSH IRMA in 57 cases with hypothyroidism are higher than normal, and have more significant positive correlation with that of TSH RIA (r 0.9566, P<0.01). The results show that the TSH IRMA with magnetic separation is a sensitive method for thyroid function test

218

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

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

Wan-Yuo Guo

2010-01-01

219

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-09-15

220

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

221

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

Science.gov (United States)

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

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

2010-08-01

222

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

International Nuclear Information System (INIS)

A novel method is described for the preparation of superparamagnetic mesoporous maghemite (?-Fe2O3)/silica (SiO2) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe3O4) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe3O4 to ?-Fe2O3 by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 deg. C feature spherical shape and uniform particle size (dparticle=1.72 ?m), high saturation magnetization (Ms=17.22 emu/g), superparamagnetism (Mr/Ms=0.023), high surface area (SBET=240 m2/g), and mesoporosity (dpore=6.62 nm). The composite microsphere consists of interlocked amorphous SiO2 nanoparticles, in which cubic ?-Fe2O3 nanocrystals are homogeneously dispersed and thermally stable against ?- to ?-phase transformation at temperatures up to 600 deg. C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phase adsorbent for raed as a solid-phase adsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A260/A280 values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

223

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.

224

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

225

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

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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

226

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

Science.gov (United States)

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

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

2015-01-01

227

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.

228

Effects of pH and Magnetic Material on Immunomagnetic Separation of Cryptosporidium Oocysts from Concentrated Water Samples  

OpenAIRE

In this study, we examined the effect that magnetic materials and pH have on the recoveries of Cryptosporidium oocysts by immunomagnetic separation (IMS). We determined that particles that were concentrated on a magnet during bead separation have no influence on oocyst recovery; however, removal of these particles did influence pH values. The optimal pH of the IMS was determined to be 7.0. The numbers of oocysts recovered from deionized water at pH 7.0 were 26.3% higher than those recovered f...

Kuhn, Ryan C.; Rock, Channah M.; Oshima, Kevin H.

2002-01-01

229

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

OpenAIRE

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

Yan, Xiaoyan; Gilman, S. Douglass

2010-01-01

230

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

Directory of Open Access Journals (Sweden)

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

Sandulyak Anna Aleksandrovna

2013-09-01

231

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

232

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

233

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

International Nuclear Information System (INIS)

A real spin-charge separation scheme is found based on a saddle-point state of the t-J model. In the one-dimensional (1D) case, such a saddle-point reproduces the correct asymptotic correlations at the strong-coupling fixed point of the model. In the two-dimensional (2D) case, the transverse gauge field confining spinon and holon is shown to be gapped at finite doping so that a spin-charge deconfinement is obtained for its first time in 2D. The gap in the gauge fluctuation disappears at half-filling limit, where a long-range antiferromagnetic order is recovered at zero temperature and spinons become confined. The most interesting features of spin dynamics and transport are exhibited at finite doping where exotic residual couplings between spin and charge degrees of freedom lead to systematic anomalies with regard to a Fermi-liquid system. In spin dynamics, a commensurate antiferromagnetic fluctuation with a small, doping-dependent energy scale is found, which is characterized in momentum space by a Gaussian peak at (?/a,?/a) with a doping-dependent width. This commensurate magnetic fluctuation contributes a non-Korringa behavior for the NMR spin-lattice relaxation rate. There also exists a characteristic temperature scale below thich a pseudogap behavior appears in the spin dynamics. Furthermore, an incommensurate magnetic fluctuation is also obtained at a finite energy regime. In the transport, a strong-range phase intereference leads to an effective holon Lagrangince leads to an effective holon Lagrangian which can give rise to a series of interesting phenomena including linear-T resistivity and a T2 Hall angle. We discuss the striking similarities of these theoretical features with those found in the high-Tc cuprates and give a consistent picture for the latter. Electronic properties like Fermi surface and superconducting pairing in this framework are also discussed

234

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

Science.gov (United States)

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

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

2012-01-15

235

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

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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

236

Evaluation of Cyanex 923-coated magnetic particles for the extraction and separation of lanthanides and actinides from nuclear waste streams  

Energy Technology Data Exchange (ETDEWEB)

In the magnetically assisted chemical separation (MACS) process, tiny ferromagnetic particles coated with solvent extractant are used to selectively separate radionuclides and hazardous metals from aqueous waste streams. The contaminant-loaded particles are then recovered from the waste solutions using a magnetic field. The contaminants attached to the magnetic particles are subsequently removed using a small volume of stripping agent. In the present study, Cyanex 923 (trialkylphosphine oxide) coated magnetic particles (cross-linked polyacrylamide and acrylic acid entrapping charcoal and iron oxide, 1:1:1, particle size=1-60 {mu}m) are being evaluated for the possible application in the extraction and separation of lanthanides and actinides from nuclear waste streams. The uptake behaviour of Th(IV), U(VI), Am(III) and Eu(III) from nitric acid solutions was investigated by batch studies. The effects of sorption kinetics, extractant and nitric acid concentrations on the uptake behaviour of metal ions were systematically studied. The influence of fission products (Cs(I), Sr(II)) and interfering ions including Fe(III), Cr(VI), Mg(II), Mn(II), and Al(III) were investigated. The recycling capacity of the extractant-coated magnetic particles was also evaluated.

Shaibu, B.S. [Chemical Sciences Division, Regional Research Laboratory (CSIR), Thiruvananthapuram-695019 (India); Reddy, M.L.P. [Chemical Sciences Division, Regional Research Laboratory (CSIR), Thiruvananthapuram-695019 (India)]. E-mail: mlpreddy@yahoo.co.uk; Bhattacharyya, A. [Radiochemistry Division, B.A.R.C, Trombay, Mumbai-400085 (India); Manchanda, V.K. [Radiochemistry Division, B.A.R.C, Trombay, Mumbai-400085 (India)

2006-06-15

237

Evaluation of Cyanex 923-coated magnetic particles for the extraction and separation of lanthanides and actinides from nuclear waste streams  

International Nuclear Information System (INIS)

In the magnetically assisted chemical separation (MACS) process, tiny ferromagnetic particles coated with solvent extractant are used to selectively separate radionuclides and hazardous metals from aqueous waste streams. The contaminant-loaded particles are then recovered from the waste solutions using a magnetic field. The contaminants attached to the magnetic particles are subsequently removed using a small volume of stripping agent. In the present study, Cyanex 923 (trialkylphosphine oxide) coated magnetic particles (cross-linked polyacrylamide and acrylic acid entrapping charcoal and iron oxide, 1:1:1, particle size=1-60 ?m) are being evaluated for the possible application in the extraction and separation of lanthanides and actinides from nuclear waste streams. The uptake behaviour of Th(IV), U(VI), Am(III) and Eu(III) from nitric acid solutions was investigated by batch studies. The effects of sorption kinetics, extractant and nitric acid concentrations on the uptake behaviour of metal ions were systematically studied. The influence of fission products (Cs(I), Sr(II)) and interfering ions including Fe(III), Cr(VI), Mg(II), Mn(II), and Al(III) were investigated. The recycling capacity of the extractant-coated magnetic particles was also evaluated

238

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

239

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

240

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

Science.gov (United States)

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

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

2013-04-15

241

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

Energy Technology Data Exchange (ETDEWEB)

A novel method is described for the preparation of superparamagnetic mesoporous maghemite (gamma-Fe{sub 2}O{sub 3})/silica (SiO{sub 2}) composite microspheres to allow rapid magnetic separation of DNA from biological samples. With magnetite (Fe{sub 3}O{sub 4}) and silica nanoparticles as starting materials, such microspheres were synthesized by the following two consecutive steps: (1) formation of monodispersed organic/inorganic hybrid microspheres through urea-formaldedyde (UF) polymerization and (2) removal of the organic template and phase transformation of Fe{sub 3}O{sub 4} to gamma-Fe{sub 2}O{sub 3} by calcination at elevated temperatures. The as-synthesized particles obtained by heating at temperature 300 deg. C feature spherical shape and uniform particle size (d{sub particle}=1.72 mum), high saturation magnetization (M{sub s}=17.22 emu/g), superparamagnetism (M{sub r}/M{sub s}=0.023), high surface area (S{sub BET}=240 m{sup 2}/g), and mesoporosity (d{sub pore}=6.62 nm). The composite microsphere consists of interlocked amorphous SiO{sub 2} nanoparticles, in which cubic gamma-Fe{sub 2}O{sub 3} nanocrystals are homogeneously dispersed and thermally stable against gamma- to alpha-phase transformation at temperatures up to 600 deg. C. With the exposed iron oxide nanoparticles coated with a thin layer of silica shell, the magnetic microspheres were used as a solid-phase adsorbent for rapid extraction of genomic DNA from plant samples. The results show that the DNA templates isolated from pea and green pepper displayed single bands with molecular weights greater than 8 kb and A{sub 260}/A{sub 280} values of 1.60-1.72. The PCR amplification of a fragment encoding the endogenous chloroplast ndhB gene confirmed that the DNA templates obtained were inhibitor-free and amenable to sensitive amplification-based DNA technologies.

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

2010-08-15

242

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

243

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

Science.gov (United States)

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

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

2013-03-21

244

Magnetic counter-gravity flow separation of electrically prepolarised lymphoid cells.  

Science.gov (United States)

A novel principle is proposed for a differential separation of live cells (such as leucocytes) from a main flow. A microfluidic device with planar insulated electrodes as the side walls of the channel was manufactured and tested. An array of insulated vertical conductor wires was inserted along the axis of the channel and used to impose Lorentz forces upon polarisable particles that moved with the flow. Polystyrene microspheres and lymphoid cell lines (DOHH2 and K562) were used to test the ability of the setting to impose a force field that induced consistent vertical motion. The direction of electric current was found to directly influence the number of cells or microspheres that were sampled at the surface of the flow. Lorentz force was considered to be active upon cells due to an overall polarisation of the membrane surface. The consequence of the magnetic force was that the polarised cells were moved vertically upwards (opposing gravity). The setting was effective for increasing the number of extracted cells from a main flow or for increasing the concentration of DOHH2 cells in a mixed population with K562 in culture medium. The limitations of the work parameters (potential-current) were found to be dependent upon the cell type. PMID:17278260

Popa, C; Su, B; Vadgama, P; Cotter, F

2007-02-01

245

Determination of nanoparticle force balance in an electrical magnetic separation system  

Directory of Open Access Journals (Sweden)

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

E.E. Volkanin

2014-04-01

246

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.'

247

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

International Nuclear Information System (INIS)

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

248

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer A improved ferromagnetic property, visible light absorption N-TiO{sub 2} was prepared by strontium ferrite as support. Black-Right-Pointing-Pointer The supported N-TiO{sub 2} had a strong ferromagnetic properties with coercivity 4187.2G, mass recovery {approx}98%. Black-Right-Pointing-Pointer The supported N-TiO{sub 2} resulted in a lower band gap energy ({approx}2.8 eV). Black-Right-Pointing-Pointer Complete degradation of 2,4-DCP was achieved in shorter duration under both bright, diffused sunlight irradiation. - Abstract: An enhanced ferromagnetic property, visible light active TiO{sub 2} photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe{sub 12}O{sub 19}) onto TiO{sub 2} doped with nitrogen (N) and compared with N-doped TiO{sub 2}. The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO{sub 2} supported on SrFe{sub 12}O{sub 19}. The supported N-TiO{sub 2} exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO{sub 2}. The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50 mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO{sub 2} and >85% degradation N-TiO{sub 2}, respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery {approx}98% for further reuse.

Aziz, Azrina Abd; Yong, Kok Soon; Ibrahim, Shaliza [Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Pichiah, Saravanan, E-mail: pichiahsaravanan@gmail.com [Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2012-01-15

249

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

International Nuclear Information System (INIS)

Highlights: ? A improved ferromagnetic property, visible light absorption N–TiO2 was prepared by strontium ferrite as support. ? The supported N–TiO2 had a strong ferromagnetic properties with coercivity 4187.2G, mass recovery ?98%. ? The supported N–TiO2 resulted in a lower band gap energy (?2.8 eV). ? Complete degradation of 2,4-DCP was achieved in shorter duration under both bright, diffused sunlight irradiation. - Abstract: An enhanced ferromagnetic property, visible light active TiO2 photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe12O19) onto TiO2 doped with nitrogen (N) and compared with N-doped TiO2. The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N–TiO2 supported on SrFe12O19. The supported N–TiO2 exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO2. The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50 mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N–TiO2 and >85% degradation N–TiO2, respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery ?98% for further reuse.

250

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)

251

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

252

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

CERN Document Server

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

Adamczyk, L; 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; Sánchez, M Calderón de la Barca; 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; Leyva, A Davila; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; de Souza, R Derradi; 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; Kosarzewski, L K; 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; Don, D M M D Madagodagettige; 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; Poniatowska, K; 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; 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

2014-01-01

253

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

Science.gov (United States)

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

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

2008-03-01

254

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 Fe2 O3 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 ?-Fe2 O3 @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

255

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

Science.gov (United States)

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

Xu, Shihong; Shangguan, Wenfeng; Yuan, Jian; Chen, Mingxia; Shi, Jianwei; Jiang, Zhi

2008-03-01

256

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

257

Evidence for magnetic phase separation in La0.86Sr0.14Mn1-xCuxO3+? manganites from NMR and magnetic measurements  

International Nuclear Information System (INIS)

Polycrystalline La0.86Sr0.14Mn1-xCuxO3+? (x = 0, 0.05, 0.10, 0.15, 0.20) manganites were investigated by means of magnetic measurements and zero-field 139La and 55Mn nuclear magnetic resonance (NMR) spectroscopy. Magnetization versus temperature measurements revealed a paramagnetic to ferromagnetic transition in most samples, with lower Curie temperatures and broader transitions for samples with higher Cu contents. The details of the magnetization measurements suggested a phase-separated scenario, with ferromagnetic clusters embedded in an antiferromagnetic matrix, especially for the samples with large Cu contents (x = 0.15 and 0.20). Zero-field 139La NMR measurements confirmed this finding, since the spectral features remained almost unchanged for all Cu-doped samples, whereas the bulk magnetization was drastically reduced with increasing Cu content. 55Mn NMR spectra were again typical of ferromagnetic regions, with a broadening of the resonance line caused by the disorder introduced by the Cu doping. The results indicate a coexistence of different magnetic phases in the manganites studied, with the addition of Cu contributing to the weakening of the double-exchange interaction in most parts of the material

258

Evidence for magnetic phase separation in La0.86Sr0.14Mn1-xCuxO3+? manganites from NMR and magnetic measurements  

Science.gov (United States)

Polycrystalline La0.86Sr0.14Mn1-xCuxO3+? (x = 0, 0.05, 0.10, 0.15, 0.20) manganites were investigated by means of magnetic measurements and zero-field 139La and 55Mn nuclear magnetic resonance (NMR) spectroscopy. Magnetization versus temperature measurements revealed a paramagnetic to ferromagnetic transition in most samples, with lower Curie temperatures and broader transitions for samples with higher Cu contents. The details of the magnetization measurements suggested a phase-separated scenario, with ferromagnetic clusters embedded in an antiferromagnetic matrix, especially for the samples with large Cu contents (x = 0.15 and 0.20). Zero-field 139La NMR measurements confirmed this finding, since the spectral features remained almost unchanged for all Cu-doped samples, whereas the bulk magnetization was drastically reduced with increasing Cu content. 55Mn NMR spectra were again typical of ferromagnetic regions, with a broadening of the resonance line caused by the disorder introduced by the Cu doping. The results indicate a coexistence of different magnetic phases in the manganites studied, with the addition of Cu contributing to the weakening of the double-exchange interaction in most parts of the material.

Freitas, Jair C. C.; Victor, Rodolfo A.; Orlando, Marcos T. D.; Takeuchi, Armando Y.; Oliveira, Ivan S.; Bonagamba, Tito J.

2008-03-01

259

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

260

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

261

Regulation of pulsed magnetic field spatial distribution by means of shielding the separated solenoid parts  

International Nuclear Information System (INIS)

An adjustment method of the spatial distribution of the pulsed magnetic field by screening some of the coils of the solenoid which sets up this field has been elaborated. The method has been tested during transportation of the electron beam with the energy of 150 keV and current of 1 kA. The focussing solenoid is made up of a screened and non-screened parts, which ensure different shape of the magnetic field pulses in these portions. By adjusting the moment of the beam injection into the magnetic field, it becomes possible to change the distribution of the magnetic field encountered by the beam, i.e. it becomes possible to change the effect of the magnetic field on the beam

262

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

263

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 SciELO South Africa | Language: English Abstract in english 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

264

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

Science.gov (United States)

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

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

2014-03-01

265

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

266

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

267

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

Science.gov (United States)

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

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

2013-11-01

268

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

OpenAIRE

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 longitud...

Nam, Seung-il

2010-01-01

269

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.

270

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

271

Phase separation and frustrated square lattice magnetism of Na1.5VOPO4F0.5  

Science.gov (United States)

Crystal structure, electronic structure, and magnetic behavior of the spin-(1)/(2) quantum magnet Na1.5VOPO4F0.5 are reported. The disorder of Na atoms leads to a sequence of structural phase transitions revealed by synchrotron x-ray powder diffraction and electron diffraction. The high-temperature second-order ??? transition at 500 K is of the order-disorder type, whereas the low-temperature ???+?' transition around 250 K is of the first order and leads to a phase separation toward the polymorphs with long-range (?) and short-range (?') order of Na. Despite the complex structural changes, the magnetic behavior of Na1.5VOPO4F0.5 probed by magnetic susceptibility, heat capacity, and electron spin resonance measurements is well described by the regular frustrated square lattice model of the high-temperature ?-polymorph. The averaged nearest-neighbor and next-nearest-neighbor couplings are J¯1?-3.7 K and J¯2?6.6 K, respectively. Nuclear magnetic resonance further reveals the long-range ordering at TN=2.6 K in low magnetic fields. Although the experimental data are consistent with the simplified square-lattice description, band structure calculations suggest that the ordering of Na atoms introduces a large number of inequivalent exchange couplings that split the square lattice into plaquettes. Additionally, the direct connection between the vanadium polyhedra induces an unusually strong interlayer coupling having effect on the transition entropy and the transition anomaly in the specific heat. Peculiar features of the low-temperature crystal structure and the relation to isostructural materials suggest Na1.5VOPO4F0.5 as a parent compound for the experimental study of tetramerized square lattices as well as frustrated square lattices with different values of spin.

Tsirlin, A. A.; Nath, R.; Abakumov, A. M.; Furukawa, Y.; Johnston, D. C.; Hemmida, M.; Krug von Nidda, H.-A.; Loidl, A.; Geibel, C.; Rosner, H.

2011-07-01

272

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

CERN Document Server

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

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

2003-01-01

273

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

Science.gov (United States)

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

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

2014-07-01

274

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...

275

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

276

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

Science.gov (United States)

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

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

2014-11-01

277

Fe3O4@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes  

International Nuclear Information System (INIS)

Highlights: ? The Fe3O4@GO composite was prepared by a facile co-precipitation method. ? Fe3O4 nanoparticles are well distributed on GO nanosheets. ? Fe3O4@GO was for the first time explored as a catalyst to reduce nitroarenes. ? Fe3O4@GO exhibits higher catalytic activity. ? The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe3O4@graphene oxide (Fe3O4@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N2 adsorption–desorption measurements. The results demonstrated that the Fe3O4 nanoparticles (Fe3O4 NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe3O4@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min?1, forty five times that of the commercial Fe3O4 NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability

278

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

279

Design of Countercurrent Separation of Ginkgo biloba Terpene Lactones by Nuclear Magnetic Resonance  

OpenAIRE

Terpene lactones such as bilobalide, ginkgolides A, B, C, and J are major bioactive compounds of Ginkgo biloba L. Purification of these compounds is tedious due to their similar chemical properties. For the purpose of developing an effective and efficient method for both analytical and preparative separation of terpene lactones in G. biloba, an innovative orthogonality-enhanced high-speed countercurrent chromatography (HSCCC) method was established. Taking advantage of quantitative 1H NMR (qH...

Qiu, Feng; Friesen, Brent J.; Mcalpine, James B.; Pauli, Guido F.

2012-01-01

280

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

OpenAIRE

With transfusional iron overload, almost all the excess iron is sequestered intracellularly as rapidly mobilizable, dispersed, soluble, ferritin iron, and as aggregated, insoluble hemosiderin iron for long-term storage. Established magnetic resonance imaging (MRI) indicators of tissue iron (R2, R2*) are principally influenced by hemosiderin iron and change slowly, even with intensive iron chelation. Intracellular ferritin iron is evidently in equilibrium with the low-molecular-weight cytosoli...

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

2010-01-01

281

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.

282

Inspection of magnetic elements using forces of separation from the pole  

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-07-01

283

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

OpenAIRE

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

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

2002-01-01

284

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

285

Development of water-bloom removal system by using a superconductive magnetic separation technique; Chodendo jiki bunri gijutsu ni yoru aoko jokyo sochi no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Purification techniques are expected to be developed in order to remove a huge amount of water-bloom at high speed, which is a kind of plankton generated in summer due to the eutrophication of lakes and marshes. This paper describes a newly developed water-bloom removal system by means of a magnetic separation technique utilizing superconductivity. Magnetic powders and flocculants are mixed and agitated in the raw water for several minutes, to form floc. Since the magnetic powders are mixed in the floc, the floc is sucked and separated at the magnetic filter by injecting this pre-treated water into the magnetic separator. Thus, purified water is drained. The trial system is wholly cooled through the conduction by cooling an edge of superconductive magnet with the very low temperature gas of a small helium refrigerator. The intensity of magnetic field is 1 tesla, and the demand is 7 kW. Purification tests were conducted using water-bloom raw water of the Kasumigaura, collected in summer, 1995. As a result, it was confirmed that 95% of the water-bloom can be separated and removed at a high speed. This system has a small size and can be mounted on a vehicle. 2 refs., 4 figs., 2 tabs.

Saho, N.; Takagi, T.; Isogami, H. [Hitachi, Ltd., Tokyo (Japan)

1996-08-01

286

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

287

Enantioselective separation of chiral aromatic amino acids with surface functionalized magnetic nanoparticles.  

Science.gov (United States)

Chiral resolution aromatic amino acids, DL-tryptophan (DL-Trp), DL-phenylalanine (DL-Phe), DL-tyrosine (DL-Tyr) from phosphate buffer solution was achieved in present study employing the concept of selective adsorption by surface functionalized magnetic nanoparticles (MNPs). Surfaces of magnetic nanoparticles were functionalized with silica and carboxymethyl-?-cyclodextrin (CMCD) to investigate their adsorption resolution characteristics. Resolution of enantiomers from racemic mixture was quantified in terms of enantiomeric excess using chromatographic method. The MNPs selectively adsorbed L-enantiomers of DL-Trp, DL-Phe, and DL-Tyr from racemic mixture and enantiomeric excesses (e.e.) were determined as 94%, 73% and 58%, respectively. FTIR studies demonstrated that hydrophobic portion of enantiomer penetrated into hydrophobic cavity of cyclodextrin molecules to form inclusion complex. Furthermore, adsorption site was explored using XPS and it was revealed that amino group at chiral center of the amino acid molecule formed hydrogen bond with secondary hydroxyl group of CMCD molecule and favorability of hydrogen bond formation resulted in selective adsorption of L-enantiomer. Finally, stability constant (K) and Gibbs free energy change (-?G°) for inclusion complexation of CMCD with L-/D-enantiomers of amino acids were determined using spectroflurometry in aqueous buffer solution. Higher binding constants were obtained for inclusion complexation of CMCD with L-enantiomers compared to D-enantiomers which stimulated enantioselective properties of CMCD functionalized magnetite silica nanoparticles. PMID:23384689

Ghosh, Sudipa; Fang, Tan Hui; Uddin, M S; Hidajat, K

2013-05-01

288

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

289

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

Energy Technology Data Exchange (ETDEWEB)

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

Reardon, K. P. [Osservatorio Astrofisico di Arcetri, 50125 Firenze (Italy); Wang, Y.-M.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Muglach, K., E-mail: kreardon@arcetri.astro.it, E-mail: yi.wang@nrl.navy.mil, E-mail: hwarren@nrl.navy.mil, E-mail: karin.muglach@nasa.gov [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2011-12-01

290

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

International Nuclear Information System (INIS)

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

291

Photocatalytic degradation of methylene blue on magnetically separable MgFe{sub 2}O{sub 4} under visible light irradiation  

Energy Technology Data Exchange (ETDEWEB)

A magnetically separable single-phase MgFe{sub 2}O{sub 4} 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 MgFe{sub 2}O{sub 4} was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe{sub 2}O{sub 4} was studied by measuring their photocurrent–potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm{sup ?2} illumination. - Graphical abstract: Highly efficient magnetically separable MgFe{sub 2}O{sub 4} photocatalyst for organic based impurities decomposition as well as for the production of H{sub 2} gas was synthesized and characterized successfully (a) MgFe{sub 2}O{sub 4} photocatalyst in polluted water, (b) The photocatalyst (MgFe{sub 2}O{sub 4}) is being attracted toward magnetic field for separation, (c) Hysteresis loop of MgFe{sub 2}O{sub 4} showing magnetic behavior. Highlights: ? New photocatalyst working in the visible range have been synthesized by facile cheap route. ? MgFe{sub 2}O{sub 4} photocatalyst showed well defined magnetically separable behavior. ? Excellent water splitting characteristics to produce H{sub 2} was observed under visible light irradiation.

Shahid, Muhammad [Material Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia); Jingling, Liu [BK21 Physics Research Division, SKKU Advanced Institute of Nanotechnology, Institute of Basic Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Ali, Zahid [National Institute of Lasers and Optronics, Nilore, Islamabad (Pakistan); Shakir, Imran [Sustainable Energy Technologies (SET) Center, King Saud University, Riyadh (Saudi Arabia); Warsi, Muhammad Farooq, E-mail: farooq.warsi@iub.edu.pk [Chemistry Department, Baghdad-ul-Jaded Campus, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Parveen, Riffat [Institute of Chemistry, University of the Punjab, Lahore (Pakistan); Nadeem, Muhammad [Department of Chemistry, University of Agriculture, Faisalabad 38040, Punjab (Pakistan)

2013-05-15

292

Separation of Intra- and Extramyocellular Lipid Signals in Proton MR Spectra by Determination of Their Magnetic Field Distribution  

Science.gov (United States)

In skeletal musculature intramyocellular (IMCL) and extramyocellular lipids (EMCL) are stored in compartments of different geometry and experience different magnetic field strengths due to geometrical susceptibility effects. The effect is strong enough to—at least partly—separate IMCL and EMCL contributions in 1H MR spectroscopy, despite IMCL and EMCL consisting of the same substances. The assessment of intramyocellular lipid stores in skeletal musculature by 1H MR spectroscopy plays an important role for studying physiological and pathological aspects of lipid metabolism. Therefore, a method using mathematical tools of Fourier analysis is developed to obtain the magnetic field distribution (MFD) from the measured spectra by deconvolution. A reference lipid spectrum is required which was recorded in tibial yellow bone marrow. It is shown that the separation of IMCL contributions can be performed more precisely—compared to other methods—based on the MFD. Examples of deconvolution in model systems elucidate the principle. Applications of the proposed approach on in vivo examinations in m. soleus and m. tibialis anterior are presented. Fitting the IMCL part of the MFD by a Gaussian lineshape with a linewidth kept fixed with respect to the linewidth of creatine and with the assumption of a smooth but not necessarily symmetrical shape for the EMCL part, the only free fit parameter, the amplitude of the IMCL part, is definite and subtraction leads to the EMCL part in the MFD. This procedure is especially justified for the soleus muscle showing a severely asymmetrical distribution which might lead to a marked overestimation of IMCL using common line fitting procedures.

Steidle, G.; Machann, J.; Claussen, C. D.; Schick, F.

2002-02-01

293

Magnetic properties and phase separation in Pr1-xSrxCoO3, using ^59Co NMR  

Science.gov (United States)

Doped transition metal oxides including manganites and cobaltites have revealed a rich variety of properties that may be technologically important. The mixed valence cobaltite Pr1-xSrxCoO3 (PSCO) has a phase diagram reminiscent of La1-xSrxCoO3 (LSCO) but with a number of significant differences. For x=0.5 the system is ferromagnetic (FM) below TC= 240 K but anomalous magnetization behavior is found close to 120 K with an associated crystal structure change from low symmetry to tetragonal with decreasing T. For x Zero-field ^59Co NMR spectra show that differences in FM character between x=0.5 and x=0.3 samples are negligibly small at temperatures in the range 3-30 K No FM line was observed for x=0.2; a narrow paramagnetic- like signal only slightly shifted from the diamagnetic ^59Co spectrum is observed in high- field NMR for all three x values, providing evidence of some form of phase separation where a paramagnetic phase coexists with the FM phase. The results will be compared with the very different phase separation data previously obtained for LSCO.

Smith, R.; Kuhns, P. L.; Hoch, M. J. R.; Moulton, W. G.; Stauffer, D.; Wu, J.; Leighton, C.

2006-03-01

294

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

Science.gov (United States)

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

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

2014-08-01

295

Magnetic phase transition for defect induced electron spins from fully metal-semiconductor separated SWCNTs  

Energy Technology Data Exchange (ETDEWEB)

ESR experiments from PtRhRe grown and highly semiconductor - metal separated single-walled carbon nanotubes (SWCNTs) were performed at 9.45 GHz and temperatures T between 0.39 and 200 K. No explicit evidence was found for a response from itinerant electrons in the metallic tubes. Rather, in both the metallic (M) and the semiconducting (SC) tubes, the ESR signal originates from quasi-localized defect spins but interactions with free electrons render the two systems characteristically different. The spin susceptibility was of Curie-Weiss type for T {>=} 10 K. For annealed samples it drops for lower T indicating a transition to a ferromagnetic state. Linewidths decrease and increase with increasing T for M and SC tubes, respectively. As a consequence they cross for the two systems. Interaction of spins with free carriers in M tubes via an RKKY type mechanism and increase of linewidth with temperature for SC tubes due to spin-lattice interaction is suggested to be responsible for this. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Havlicek, M.; Jantsch, W. [Institut f. Halbleiter- und Festkoerperphysik, Johannes Kepler Universitaet, 4040 Linz (Austria); Chernov, A.; Kuzmany, H. [Fakultaet fuer Physik, Universitaet Wien, Strudlhofgasse 4, 1090 Wien (Austria); Wilamowski, Z. [Polish Academy of Sciences, Al. Lotnikov 32/46, 02-668 Warsaw (Poland); Yanagi, K. [Department of Physics, Tokyo Metropolitan University (Japan); Kataura, H. [Nanotechnology Research Institute, AIST, 1-1-1 Higashi, Tsukuba 305-8562 (Japan); Ruemmeli, M.H. [Leibniz Institut fuer Festkoerperphysik und Werkstoffforschung, Dresden (Germany); Malissa, H. [Department of Electrical Engineering, Princeton University, Princeton, NJ (United States)

2012-12-15

296

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

Science.gov (United States)

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

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

2013-05-01

297

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

Science.gov (United States)

In this study, a new method combining magnetic separation (MS) and surface-enhanced Raman scattering (SERS) was developed to detect genetically modified organisms (GMOs). An oligonucleotide probe which is specific for 35 S DNA target was immobilized onto gold coated magnetic nanospheres to form oligonucleotide-coated nanoparticles. A self assembled monolayer was formed on gold nanorods using 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) and the second probe of the 35 S DNA target was immobilized on the activated nanorod surfaces. Probes on the nanoparticles were hybridized with the target oligonucleotide. Optimization parameters for hybridization were investigated by high performance liquid chromatography. Optimum hybridization parameters were determined as: 4 ?M probe concentration, 20 min immobilization time, 30 min hybridization time, 55 °C hybridization temperature, 750 mM buffer salt concentration and pH: 7.4. Quantification of the target concentration was performed via SERS spectra of DTNB on the nanorods. The correlation between the target concentration and the SERS signal was found to be linear within the range of 25-100 nM. The analyses were performed with only one hybridization step in 40 min. Real sample analysis was conducted using Bt-176 maize sample. The results showed that the developed MS-SERS assay is capable of detecting GMOs in a rapid and selective manner. PMID:22049365

Guven, Burcu; Boyac?, ?smail Hakk?; Tamer, Ugur; Çal?k, P?nar

2012-01-01

298

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

Science.gov (United States)

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

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

2012-01-01

299

A Novel Method for Quantitative Analysis of Anti-MUC1 Expressing Ovarian Cancer Cell Surface Based on Magnetic Cell Separation  

OpenAIRE

Scope of this study is to describe a simple, rapid, accurate, inexpensive and easily available in vitro method based on magnetic nanoparticles and magnetic cell separation principle to quantitative analysis the cell surface antigen expression of ovarian cancer cells surface (MUC1). In this work, superparamagnetic iron oxide nanoparticles (SPIONs) attached to monoclonal antibody (mAb) C595 that binds to ovarian cancer cells. Conjugation of mAb C595 to commercial SPIONs was achieve...

Daryoush Shahbazi-Gahrouei; Mohammad Abdolahi

2012-01-01

300

Spatially separated indirect photoemission in undoped ZnSe/BeTe type-II quantum wells studied in pulse magnetic fields  

International Nuclear Information System (INIS)

Spatially separated indirect photoemission in an undoped ZnSe/BeTe type-II quantum structure is investigated by applying pulse magnetic field up to 50 T. A method was applied to extract the intrinsic circular polarization degree from photoluminescence (PL) with strong in-plane anisotropy. The magnetic field dependences of the circularly dichroic PL are explained by an optical transition model associated with a positively charged exciton composed of an electron and two light holes. The positively charged exciton PL is strongly suppressed by the magnetic field and also by temperature

301

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

302

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.

303

Magnetically separable hybrid CdS-TiO{sub 2}-Fe{sub 3}O{sub 4} nanomaterial: Enhanced photocatalystic activity under UV and visible irradiation  

Energy Technology Data Exchange (ETDEWEB)

Magnetically separable photocatalyst of TiO{sub 2}-CdS-Fe{sub 3}O{sub 4}@SiO{sub 2} 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 TiO{sub 2} toward the degradation of RhB under both UV and visible irradiation. This is attributed to the charge separation and transformation from CdS to TiO{sub 2}. The hysteresis loop of TiO{sub 2}-CdS-Fe{sub 3}O{sub 4}@SiO{sub 2} nanocomposite indicates an excellent magnetic property with the saturated magnetization of 9 emu/g. We also show the fast magnetic separation behaviour of the TiO{sub 2}-CdS-Fe{sub 3}O{sub 4}@SiO{sub 2} nanocomposite to remove and recycle the photocatalyst from the solution. These indicate TiO{sub 2}-CdS-Fe{sub 3}O{sub 4}@SiO{sub 2} nanocomposite is an effective and convenient recyclable photocatalyst.

Bian, Xiaofang; Hong, Kunquan, E-mail: hongkq@gmail.com; Liu, Liqing; Xu, Mingxiang, E-mail: mxxu@seu.edu.cn

2013-09-01

304

Effects of relative density on microwave heating of various carbon powder compacts microwave-metallic multi-particle coupling using spatially separated magnetic fields  

Science.gov (United States)

We have investigated the microwave heating characteristics of non-magnetic conductive multi-particle systems using spatially separated electric and magnetic fields (Emax and Hmax, respectively) to determine the effects of the multi-particle structure on microwave heating. Pure carbon, carbon black, and artificial graphite multi-particle systems exhibited peak microwave absorption at specific relative densities only under Hmax. These absorptions can be categorized into two types: one originates from coupling between metal spheres, while the other originates from a heterogeneous distribution of particles.

Kashimura, K.; Hasegawa, N.; Suzuki, S.; Hayashi, M.; Mitani, T.; Shinohara, N.; Nagata, K.

2013-01-01

305

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

Science.gov (United States)

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

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

2009-09-01

306

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

307

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

308

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)

309

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

International Nuclear Information System (INIS)

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

310

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

311

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

312

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-08-15

313

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

314

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

CERN Document Server

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

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

2004-01-01

315

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

316

A Novel Method for Quantitative Analysis of Anti-MUC1 Expressing Ovarian Cancer Cell Surface Based on Magnetic Cell Separation  

Directory of Open Access Journals (Sweden)

Full Text Available Scope of this study is to describe a simple, rapid, accurate, inexpensive and easily available in vitro method based on magnetic nanoparticles and magnetic cell separation principle to quantitative analysis the cell surface antigen expression of ovarian cancer cells surface (MUC1. In this work, superparamagnetic iron oxide nanoparticles (SPIONs attached to monoclonal antibody (mAb C595 that binds to ovarian cancer cells. Conjugation of mAb C595 to commercial SPIONs was achieved using a heterobifunctional linker sulfo-SMCC. The capability of the method was compared with flow cytometry as a gold standard and showed that both methods provide approximately the same results. This demonstrates the high potential of antigen-specific (anti-MUC1 expressing ovarian cancer magnetic cell separation of C595 mAb coated with SPIONs-C595 for quantitative cell surface antigen detection and analysis. Overall, SPIONs-C595 nano-probe is potentially both, a selective ovarian molecular imaging tool as well as a therapeutic agent.

Daryoush Shahbazi-Gahrouei

2012-01-01

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

Facile preparation of magnetic separable powdered-activated-carbon/Ni adsorbent and its application in removal of perfluorooctane sulfonate (PFOS) from aqueous solution.  

Science.gov (United States)

The main aim of this study was to synthesize magnetic separable Nickel/powdered activated carbon (Ni/PAC) and its application as an adsorbent for removal of PFOS from aqueous solution. In this work, the synthesized adsorbent using simple method was characterized by using X-ray diffractionometer (XRD), surface area and pore size analyzer, vibrating sample magnetometer (VSM), and high resolution transmission electron microscope (HRTEM). The surface area, pore volume and pore size of synthesized PAC was 1521.8 m(2)g(-1), 0.96 cm(3)g(-1), 2.54 nm, respectively. Different kinetic models: the pseudo-first-order model, the pseudo-second-order model, and three adsorption isotherms--Langmuir, Freundlich and Temkin--were applied to study the sorption kinetics and isothermal behavior of PFOS onto the surface of an as-prepared adsorbent. The rate constant using the pseudo-second-order model for removal of 150 ppm PFOS was estimated as 8.82×10(-5) and 1.64×10(-4) for PAC and 40% Ni/PAC, respectively. Our results demonstrated that the composite adsorbents exhibited a clear magnetic hysteretic behavior, indicating the potential practical application in magnetic separation of adsorbents from aqueous solution phase as well. PMID:21961696

Liang, Xuanqi; Gondal, Mohammed A; Chang, Xiaofeng; Yamani, Zain H; Li, Nianwu; Lu, Hongling; Ji, Guangbin

2011-01-01

319

Dynamical spin separation in a double quantum well of diluted magnetic semiconductor due to spin-dependent type-II band alignment  

International Nuclear Information System (INIS)

Dynamical spin separation is studied in a double quantum well composed of diluted magnetic semiconductor (DMS) of Zn0.71Cd0.26Mn0.03Se and non-magnetic Zn0.73Cd0.27Se, by means of time-resolved circularly polarized photoluminescence (PL). The giant Zeeman shift of excitonic PL with ?+-circular polarization increases with increasing magnetic field, indicating the type-II transition between an electron in the Zn0.73Cd0.27Se and a heavy hole (hh) in the DMS with down-spin states. Excitonic PL due to the type-I transition inside the Zn0.73Cd0.27Se well is simultaneously observed with ?- polarization. The lifetime of the type-II transition increases from 70 to 140 ps with increasing field up to 3.5 T and then saturates. These results show spatial separation of the hh-spins, which is sustained by a relatively slow injection time of 300 ps of the hh-spin from the Zn0.73Cd0.27Se to the DMS wells

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

Evidence for magnetic phase separation in La{sub 0.86}Sr{sub 0.14}Mn{sub 1-x}Cu{sub x}O{sub 3+{delta}} manganites from NMR and magnetic measurements  

Energy Technology Data Exchange (ETDEWEB)

Polycrystalline La{sub 0.86}Sr{sub 0.14}Mn{sub 1-x}Cu{sub x}O{sub 3+{delta}} (x = 0, 0.05, 0.10, 0.15, 0.20) manganites were investigated by means of magnetic measurements and zero-field {sup 139}La and {sup 55}Mn nuclear magnetic resonance (NMR) spectroscopy. Magnetization versus temperature measurements revealed a paramagnetic to ferromagnetic transition in most samples, with lower Curie temperatures and broader transitions for samples with higher Cu contents. The details of the magnetization measurements suggested a phase-separated scenario, with ferromagnetic clusters embedded in an antiferromagnetic matrix, especially for the samples with large Cu contents (x = 0.15 and 0.20). Zero-field {sup 139}La NMR measurements confirmed this finding, since the spectral features remained almost unchanged for all Cu-doped samples, whereas the bulk magnetization was drastically reduced with increasing Cu content. {sup 55}Mn NMR spectra were again typical of ferromagnetic regions, with a broadening of the resonance line caused by the disorder introduced by the Cu doping. The results indicate a coexistence of different magnetic phases in the manganites studied, with the addition of Cu contributing to the weakening of the double-exchange interaction in most parts of the material.

Freitas, Jair C C; Victor, Rodolfo A; Orlando, Marcos T D; Takeuchi, Armando Y [Departamento de Fisica, Universidade Federal do Espirito Santo, Avenida Fernando Ferrai 514, Goiabeiras, 29075-910, Vitoria, ES (Brazil); Oliveira, Ivan S [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Urca, 22290-180, Rio de Janeiro (Brazil); Bonagamba, Tito J [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, PO Box 369, 13560-970, Sao Carlos, SP (Brazil)], E-mail: jair@npd.ufes.br

2008-03-05

322

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

323

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

324

Radioactive substance separation systems  

International Nuclear Information System (INIS)

Purpose: To enable separation of fission products, radioactive corrosion products and the likes in primary coolants with no requirement for the replacement of separation system during plant service life, by providing protruded magnetic pole plates in a liquid metal flow channel to thereby form slopes magnetic fields. Constitution: A plurality of magnetic pole plates are disposed vertically in a comb-like arrangement so as not to contact with each other along the direction of flow in a rectangular primary coolant pipeway at the exit of the reactor core in an LMFBR type reactor. Large magnetic poles are provided to the upper and lower sides of the pipeway and coils are wound on the side opposed to the pipeway. When electrical current is supplied to the coils, the magnetic pole is magnetized intensely and thus the magnetic pole plates are also magnetized intensely and thus the magnetic pole plates are also magnetized intensely to form large gradient in the magnetic fields between the upper and lower magnetic plates, whereby ferromagnetic and ferrimagnetic fission products and radioactive corrosion products in the coolants are intensely adsorbed and not detached by the flow of the coolants. Accordingly, the fission products and the radioactive corrosion products can surely be removed with no requirement for the exchange of separation system during plant service life. (Horiuchi, T.)

325

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)

326

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

327

Sm1-xSrxMnO3 manganites: unusual magnetic, electric and elastic properties due to phase separation  

International Nuclear Information System (INIS)

Colossal magnetoresistance (CMR) (??/?) and giant negative volume magnetostriction (?) have been observed in the Curie temperature region of Sm1-xSrxMnO3 manganites, for x=0.33 compounds containing ferromagnetic (FM) and A-type antiferromagnetic (AFM) clusters and for x 0.4, 0.45 compounds containing FM and both types of AFM clusters (A-type and charge-ordering (CO) type). For x=0.33, the magnetization ?, ??/? and ? increase smoothly with magnetic field increase and saturation of ??/? and ? is not achieved. Isotherms of ?, ??/? and ? for x=0.4 and 0.45 show another behaviour: sharp jumps of ?, ??/? and ? take place at HC1?H?HC2, and saturation is achieved at H?HC2. We consider that the reason for CMR and giant magnetostriction being observed in the compounds investigated is the increase of the FM phase volume under the action of the magnetic field. For x=0.33 this increase is smooth because it arises from FM phase 'sprouting' on FM layers of A-type AFM phase. For x=0.4 and 0.45 the increase of the volume of the FM part arises from CO clusters with CE-type AFM structure too. In this case, CO clusters are completely transformed to the FM state with a large saturation magnetization ?s which is equal to ?70% of ?s at T=1.5 K. This transition is accompanied by crystal structure reconstruction that is manifested in both the temperature and magnetic field ic field dependences of the anisotropic magnetostriction. (author). Letter-to-the-editor

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

The metastable bound state of a pair of two-dimensional spatially separated electrons in antiparallel magnetic fields  

International Nuclear Information System (INIS)

We propose a new mechanism for binding of two equally charged carriers in a double-layer system subjected to 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 where in one layer the carrier is in the zero (n = 0) Landau level while in the other layer the carrier is 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 a nonmonotonic one: a local maximum and a local minimum appear, indicating the emergence of a metastable bound state of two carriers with the same sign of electrical charge

330

Dependence of magnetic field sensitivity of a magnetoelectric laminate sensor pair on separation distance: Effect of mutual inductance  

Science.gov (United States)

The effect of mutual inductance on the performance of a pair of Metglas/Pb(Zr,Ti)O3 laminate magnetoelectric (ME) sensors has been studied. The effective value of the ME coefficient (?ME) for the laminates was reduced when the distance between was 40 mm, the effect of mutual inductance was small. The laminates exhibited the maximum values of ?ME. The ME sensor unit with two laminates connected in parallel had higher magnetic field sensitivities.

Li, Menghui; Wang, Yaojin; Gao, Junqi; Gray, David; Li, Jiefang; Viehland, D.

2012-02-01

331

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

332

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

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

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

International Nuclear Information System (INIS)

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

335

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

336

Magnets  

International Nuclear Information System (INIS)

A magnet pole piece for an NMR imaging magnet is made of a plurality of magnetic wires with one end of each wire held in a non-magnetic spacer, the other ends of the wires being brought to a pinch, and connected to a magnetic core. The wires may be embedded in a synthetic resin and the magnetisation and uniformity thereof can be varied by adjusting the density of the wires at the spacer which forms the pole piece. (author)

337

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

338

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

CERN Document Server

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

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

2006-01-01

339

Fe{sub 3}O{sub 4}@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? The Fe{sub 3}O{sub 4}@GO composite was prepared by a facile co-precipitation method. ? Fe{sub 3}O{sub 4} nanoparticles are well distributed on GO nanosheets. ? Fe{sub 3}O{sub 4}@GO was for the first time explored as a catalyst to reduce nitroarenes. ? Fe{sub 3}O{sub 4}@GO exhibits higher catalytic activity. ? The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe{sub 3}O{sub 4}@graphene oxide (Fe{sub 3}O{sub 4}@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N{sub 2} adsorption–desorption measurements. The results demonstrated that the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe{sub 3}O{sub 4}@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min{sup ?1}, forty five times that of the commercial Fe{sub 3}O{sub 4} NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability.

He, Guangyu [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Liu, Weifeng; Sun, Xiaoqiang [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Chen, Qun, E-mail: chenqunjpu@yahoo.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China); Wang, Xin [Key Laboratory of Ministry of Education for Soft Chemistry and Functional Materials, Nanjing University of Science and Technology, Nanjing 210094 (China); Chen, Haiqun, E-mail: hqchenyf@hotmail.com [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, Changzhou University, Jiangsu Province, Changzhou 213164 (China)

2013-05-15

340

Optimization of a phase separation based magnetic-stirring salt-induced liquid-liquid microextraction method for determination of fluoroquinolones in food.  

Science.gov (United States)

Herein, we developed a novel integrated apparatus to perform phase separation based on magnetic-stirring, salt-induced, liquid-liquid microextraction for determination of five fluoroquinolones in animal-based foods by HPLC analysis. The novel integrated apparatus consisted of three simple HDPE (high density polyethylene) parts that were used to separate the solvent from the aqueous solution prior to retrieving the extractant. The extraction parameters were optimized using the response surface method based on central composite design: 791?L of acetone solvent, 2.5g of Na2SO4, pH 1.7, 3.0min of stir time, and 5.5min centrifugation. The limits of detection were 0.07-0.53?gkg(-1) and recoveries were 91.6-105.0% for the five fluoroquinolones from milk, eggs and honey. This method is easily constructed from inexpensive materials, extraction efficiency is high, and the approach is compatible with HPLC analysis. Thus, it has excellent prospects for sample pre-treatment and analysis of fluoroquinolones in animal-based foods. PMID:25577068

Gao, Ming; Wang, Huili; Ma, Meiping; Zhang, Yuna; Yin, Xiaohan; Dahlgren, Randy A; Du, Dongli; Wang, Xuedong

2015-05-15

341

Temperature dependence of Magnetic Phase separation in La_1-xSr_xCoO3 by ^139La NMR  

Science.gov (United States)

Recent work, both zero-field and high-field ^59Co NMR, has confirmed nano-scale phase separation in La_1-xSr_xCoO3 (LSCO) for x values( 0.1?x?0.5 ). However, ^59Co provides limited information on the LSCO phase diagram since short relaxation times limit measurements to temperatures below 25 K. ^139La spectra, x values 0.1 to 0.3, at fields 10 to 22 T, provide further detailed information on the evolution of the phases with temperature through the Curie point Tc 240 K. The hyperfine couplings permit identification of the various phases as ferromagnetic ( FM), spin-glass (SG),and low-spin (LS). The data suggests that spin state conversions occur for increasing temperature changing the relative concentration of the different phases. The results show that the previously suggested phase diagram must be modified to capture the intricate changes in properties that occur as a function of temperature.

Kuhns, P. L.; Hoch, M. J. R.; Lu, J.; Moulton, W. G.; Leighton, C.; Wu, J.

2004-03-01

342

Utilization of radical scavenging to develop nuclear spin polarization and magnetic isotope separation in long flexible biradicals  

Energy Technology Data Exchange (ETDEWEB)

Irradiation of argon-purged acetonitrile solutions of 2-phenylcyclododecanone (1) in the probe of a 250-MHz NMR spectrometer does not produce significant {sup 1}H or {sup 13}C chemically induced dynamic nuclear polarization (CIDNP). However, irradiation of 1 in oxygen-purged acetonitrile, argon-purged acetonitrile containing small amounts of bromotrichloromethane, or argon-purged carbon tetrachloride solutions, in the probe of a 250-MHz NMR spectrometer, produces intense {sup 1}H and {sup 13}C CIDNP. Irradiation of argon-purged acetonitrile solutions of 1 in the earth's field does not lead to measurable {sup 13}C enrichment of the recovered starting material or in the products of photolysis. However, irradiation of 1 in carbon tetrachloride or in acetonitrile solutions purged with oxygen or containing small amounts of bromotrichloromethane results in significant enrichment of an isomeric product, 2. The development of CIDNP and of isotopic enrichment is proposed to result from a common feature of the systems containing oxygen, carbon tetrachloride, or bromotrichloromethane (as scavengers) for the triplet biradical ({sup 3}BR) produced by homolytic cleavage of electronically excited 1. This competitive pathway, when its rate is within an appropriate kinetic window, provides a mechanism for effective sorting of nuclear spins to develop CIDNP and the effective sorting of nuclear isotopes to develop isotopic separation.

Turro, N.J.; Hwang, Kuo Chu; Rao, V.P.; Doubleday, C. Jr. (Columbia Univ., New York, NY (USA))

1991-03-07

343

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

International Nuclear Information System (INIS)

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

344

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

345

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

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?gmL(-1), 5.0ngmL(-1), 0.9993 and 2.8% (n=3, c=4.00?gmL(-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

347

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

348

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

Science.gov (United States)

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

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

2012-06-21

349

Magnetic BaFe{sub 12}O{sub 19} nanofiber filter for effective separation of Fe{sub 3}O{sub 4} nanoparticles and removal of arsenic  

Energy Technology Data Exchange (ETDEWEB)

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{sup ?1}) barium hexaferrite (BaFe{sub 12}O{sub 19}, 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 (Fe{sub 3}O{sub 4}) 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{sup ?1} As-contaminated water can be purified rapidly at a material cost of less than 2 US cents.

Byun, Jeehye; Patel, Hasmukh A.; Yavuz, Cafer T., E-mail: yavuz@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Graduate School of EEWS (Korea, Republic of)

2014-12-15

350

MAGNET  

CERN Multimedia

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

B. Curé

2012-01-01

351

Isotope separation  

International Nuclear Information System (INIS)

Due to their mass differences the isotopes of an element have slighty different physical and chemical properties on which the processes for isotope separation are based. The separation effect of a single separation operation normally is so small that only the multiple repetition (up to one thousand times) of the single separation step leads to the enrichment necessary for technical application. Theory and technique of isotope separation are illustrated by a description of the technically well established processes for the enrichment of U235 (diffusion, separation nozzle and centrifuge) and heavy water (distillation, chemical exchange) both of which are important for nuclear energy. Some exemplary calculations demonstrate the formidable problem of large scale isotope separation. (orig.) 891 HK/orig. 892 MKO

352

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

353

MAGNET  

CERN Multimedia

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

B. Curé

2013-01-01

354

Electronic phase separation in La sub 1 sub . sub 2 Sr sub 1 sub . sub 8 Mn sub 2 O sub 7 observed by sup 5 sup 5 Mn nuclear magnetic resonance  

CERN Document Server

A single crystal of perovskite bilayer manganite La sub 1 sub . sub 2 Sr sub 1 sub . sub 8 Mn sub 2 O sub 7 has been studied by the sup 5 sup 5 Mn NMR technique. The observed spectra at 4.2 K in zero external magnetic field are broad and spread in the frequency range 310-480 MHz. The shape of the spectrum depends strongly on the rf radiation field for exciting and refocusing a spin-echo signal. In external magnetic fields up to 1.75 T, signals arising from both metallic and insulating phases are observed, which is an evidence of the electronic phase separation. (author)

Shimizu, K; Renard, J P; Pevcolevschi, A

2003-01-01

355

Chiral Separations  

Science.gov (United States)

The main goal of this review is to provide a brief overview of chiral separations to researchers who are versed in the area of analytical separations but unfamiliar with chiral separations. To researchers who are not familiar with this area, there is currently a bewildering array of commercially available chiral columns, chiral derivatizing reagents, and chiral selectors for approaches that span the range of analytical separation platforms (e.g., high-performance liquid chromatography, gas chromatography, supercritical-fluid chromatography, and capillary electrophoresis). This review begins with a brief discussion of chirality before examining the general strategies and commonalities among all of the chiral separation techniques. Rather than exhaustively listing all the chiral selectors and applications, this review highlights significant issues and differences between chiral and achiral separations, providing salient examples from specific classes of chiral selectors where appropriate.

Stalcup, A. M.

2010-07-01

356

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

357

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

358

Optics of mass separator I  

Energy Technology Data Exchange (ETDEWEB)

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

Balestrini, S.J.

1981-07-01

359

Ferromagnetism, phase separation and ultrasharp magnetization multisteps below 40 K in the ordered “112” cobaltites EuBaCo1.92M0.08O5.5-? (M=Zn,Cu )  

Science.gov (United States)

The study of the "112" ordered oxygen-deficient perovskites EuBaCo 2O 5.43, EuBaCo 1.92Zn 0.08O 5.45, and EuBaCo 1.92Cu 0.08O 5.40 evidences a magnetic transition at 40 K which may be due to the ordering of europium moments. Below 40 K, one observes phase separation that consists of superparamagnetic droplets and ferromagnetic (FM) regions embedded in an antiferromagnetic matrix. The existence of two sorts of crystallographic sites for cobalt, and its trivalent state, suggest that these phenomena correspond to ferromagnetism induced by the presence of intermediate spin Co 3+ species. Moreover, the magnetization hysteresis loops of the Zn- and Cu-doped phases exhibit ultrasharp magnetization multisteps, which are interpreted by the pinning effect of Zn 2+ and Cu 2+ cations at the narrow domain walls of the FM phase.

Raveau, B.; Simon, Ch.; Pralong, V.; Caignaert, V.; Lefèvre, F.-X.

2006-08-01

360

MAGNET  

CERN Multimedia

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

B. Curé

361

MAGNET  

CERN Multimedia

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

Benoit Curé

2010-01-01

362

Surface molecular imprinting onto fluorescein-coated magnetic nanoparticles via reversible addition fragmentation chain transfer polymerization: A facile three-in-one system for recognition and separation of endocrine disrupting chemicals  

Science.gov (United States)

In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads via reversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17?-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals.In this study, we present a general protocol for the making of surface-imprinted magnetic fluorescence beads via reversible addition-fragmentation chain transfer polymerization. The resulting composites were characterized by X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy. The as-synthesized beads exhibited homogeneous polymer films (thickness of about 5.7 nm), spherical shape, high fluorescence intensity and magnetic property (Magnetization (Ms) = 3.67 emu g-1). The hybrids bind the original template 17?-estradiol with an appreciable selectivity over structurally related compounds. In addition, the resulting hybrids performed without obvious deterioration after five repeated cycles. This study therefore demonstrates the potential of molecularly imprinted polymers for the recognition and separation of endocrine disrupting chemicals. Electronic supplementary information (ESI) available: Supplementary figure S1. The hysteresis loop of Fe3O4 (a), Fe3O4@SiO2 (b), and Fe3O4@SiO2-Dye-SiO2 (c). See DOI: 10.1039/c0nr00614a

Li, Ying; Dong, Cunku; Chu, Jia; Qi, Jingyao; Li, Xin

2011-01-01

363

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

International Nuclear Information System (INIS)

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

364

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

365

Isotopic separation  

International Nuclear Information System (INIS)

This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235U from other uranium isotopes including 238U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF6 molecules in HBr molecules so as to collapse the V3 vibrational mode of the UF6 molecule the 235UF6 molecules are selectively excited to promote reduction of UF6 molecules containing 235U and facilitate separation. (UK)

366

Product separator  

International Nuclear Information System (INIS)

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

367

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

368

MAGNET  

CERN Multimedia

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

B. Curé

369

Separation of gas mixtures  

International Nuclear Information System (INIS)

Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

370

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

CERN Document Server

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

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

2003-01-01

371

Isotope separation apparatus  

International Nuclear Information System (INIS)

Isotope separation apparatus consisting of a plurality of cells disposed adjacent to each other in an evacuated container. A common magnetic field is established extending through all of the cells. A source of energetic electrons at one end of the container generates electrons which pass through the cells along the magnetic field lines. Each cell includes an array of collector plates arranged in parallel or in tandem within a common magnetic field. Sets of collector plates are disposed adjacent to each other in each cell. Means are provided for differentially energizing ions of a desired isotope by applying energy at the cyclotron resonant frequency of the desired isotope. As a result, the energized desired ions are preferentially collected by the collector plates

372

Magnetic, thermal and transport properties of phase-separated La{sub 0.27}Nd{sub 0.4}Ca{sub 0.33}MnO{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

The magnetic, resistive and thermal properties of the phase-separated compound La{sub 0.27}Nd{sub 0.4}Ca{sub 0.33}MnO{sub 3} have been experimentally studied. The sample is found to experience a charge/orbital ordering transition at {approx}175 K and an antiferromagnetic (AFM) transition at {approx}156 K without a magnetic field. A magnetic field stabilizes the ferromagnetic (FM) order and the field-induced FM phase coexists with the AFM phase under a field below 2 T in the temperature range below T{sub C}{approx}110 K. However, the magnetic entropy change accompanying the AFM-FM transition is negligibly small when T{sub C}T{sub N}. A general relation between resistivity and magnetization, {rho} A{sub 0}Texp[({epsilon}-800m{sup 2})/T] (m = normalized magnetization), is established for the paramagnetic phase, which is also applicable to other compounds with different characters, such as the La{sub 0.67}Ca{sub 0.33}MnO{sub 3} film and the La{sub 0.474}Bi{sub 0.193}Ca{sub 0.33}Mn{sub 0.994}Cr{sub 0.006}O{sub 3} and Eu{sub 0.55}Sr{sub 0.45}MnO{sub 3} ceramics. In the FM state, the resistivity is quite sensitive to the change of spin alignment and exhibits an exponential decrease with magnetization {rho} = {rho}{sub 0}exp(-22.7m). Field-induced phase separation is believed to be responsible for the distinct properties of La{sub 0.27}Nd{sub 0.4}Ca{sub 0.33}MnO{sub 3}.

Wang, J Z; Sun, J R; Liu, G J; Hu, F X; Chen, R J; Zhao, T Y; Shen, B G [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: jrsun@g203.iphy.ac.cn

2008-08-13

373

Recoil separators  

CERN Document Server

Recoil separators operating in the vacuum mode play a key role in a number of current research areas, including searches for superheavy elements, the study of nuclei far from stability and nuclear astrophysics. I will review some of these facilities, and will discuss ideas for improving the selectivity and efficiency of these devices.

Davids, C N

2003-01-01

374

Isotope separation  

International Nuclear Information System (INIS)

Research on laser isotope separation started in the early 1970s in the U.S. and Soviet Union, centering on uranium enrichment. These studies were aimed at developing advanced isotope separation techniques (atomic process, molecular process, laser process). A new molecular process, called infra-red multi-photon dissociation (IRMPD), was developed also in the 1970s. Research and development of atomic processes have been acitvely performed in many countries since the mid-1980. In Japan, the Institute of Physical and Chemical Research successfully developed large-power 16 ?m infra-red laser to be used for uranium enrichment by IRMPD. A separation factor of larger than four was achieved for uranium separation in 1987. This suggests that 3 % enriched uranium would be produced without cascade. Both the IRMPD and IR/UV (combined use of infra-red laser and ultraviolet laser) techniques use UF6, which is jetted from a nozzle to form a superheated gas flow of 50 - 100 k. The flow is irradiated with infra-red laser beam for excitation. Then excited 235UF6 is dissociated into 235UF5 and F. Another technique is the use of para-hydrogen Raman Laser. The Institute of Physical and Chemical Research also successfully developed variable-wavelength CO2 laser. (Nogami, K.)

375

MAGNET  

CERN Multimedia

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

Benoit Curé

376

MAGNET  

CERN Multimedia

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

B. Curé

377

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

378

Magnetic and electron transport properties of the rare earth cobaltates, La0.7-xLnxCa0.3CoO3 (Ln = Pr, Nd, Gd and Dy): a case of phase separation  

International Nuclear Information System (INIS)

Magnetic and electrical properties of four series of rare earth cobaltates of the formula La0.7-xLnxCa0.3CoO3 with Ln = Pr, Nd, Gd and Dy have been investigated. Compositions close to x = 0.0 contain large ferromagnetic clusters or domains, and show Brillouin-like behaviour of the field-cooled DC magnetization data with fairly high ferromagnetic Tc values, besides low electrical resistivities with near-zero temperature coefficients. When x>0.0, the zero-field-cooled data generally show a non-monotonic behaviour with a peak at a temperature slightly lower than Tc. The compositions near x = 0.0 show a prominent peak corresponding to the Tc in the AC susceptibility data. The ferromagnetic Tc varies linearly with x or the average radius of the A-site cations, A>. With increase in x or decrease in A>, the magnetization value at any given temperature decreases markedly and the AC susceptibility measurements show a prominent transition arising from small magnetic clusters with some characteristics of a spin glass. Electrical resistivity increases with increase in x, showing a significant increase around a critical value of x or A>, at which composition the small clusters also begin to dominate. These properties can be understood in terms of a phase separation scenario wherein large magnetic clusters give way to smaller ones with increase in x, with cto smaller ones with increase in x, with clusters of both types being present in certain compositions. The changes in magnetic and electrical properties occur in parallel since the large ferromagnetic clusters are hole rich and the small clusters are hole poor. Variable range hopping seems to occur at low temperatures in these cobaltates

379

Oscillator strengths for lines of the F(0, 0, 0)--X(0, 0, 0) band of H2O at 111.5 nanometers and the abundance of H2O in diffuse interstellar clouds  

International Nuclear Information System (INIS)

Absolute oscillator strengths (f-values) for rorational lines of the F(0, 0, 0)--X(0, 0, 0) band of H2O at 111.5 nm have been measured with an uncertainty of +- 40% using quantitative photographic techniques. The f-value for the 111--000 line, the one most likely to be seen in absorption in interstellar clouds, is (3.0 +- 1.2) x 10-2. This value is combined with a measured upper limit for absorption by this line in the zeta Oph cloud to show that the column density of H2O in the O00 level is less than 5.3 +- 1012 cm-2. This upper limit is larger than the predictions of gas-phase, chemical models of this cloud. We show that definite detection of H2O in diffuse clouds at the level of this upper limit would be in conflict with models of molecular formation in shock-heated gas. The data analysis produced additional results: the absolute scale of the oscillator strengths for lines of the C(0, 0, 0)--X(0, 0, 0) band of H2O at 124 nm is reduced by 10%; the integrated absorption coefficients for F--X and C--X bands are compared to calculated and measured values and agree within the experimental uncertainties

380

Study on the phase separation of La0.7Sr0.3MnO3 nanoparticles by electron magnetic resonance  

International Nuclear Information System (INIS)

In this work, the technique of electron magnetic resonance (EMR) is used to measure the magnetic resonant spectra of La0.7Sr0.3MnO3 nanoparticles synthesized by sol-gel routes with three different gelation agents (S1: Urea+citric acid; S2: citric acid, and S3: Urea+tri-sodium citrate). The purpose of this study is to investigate the influence of synthesis conditions on the magnetic properties of nanoparticles. Our ESR results show that Curie temperatures of La0.7Sr0.3MnO3 nanoparticles with different gelation agents are slightly different (T c?340 to 360 K) and possess both paramagnetic (PM) and ferromagnetic (FM) phases in the temperature below T c. Besides, a sharp FM-PM transition indicates that the combined agent of Urea+tri-sodium citrate creates a better quality in CMR nanomagnets

381

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

International Nuclear Information System (INIS)

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

382

Pressure effect on magnetism in phase-separated Cr-doped Pr0.5Ca0.5Mn1- x Cr x O3 manganites  

International Nuclear Information System (INIS)

Magnetic properties of Pr0.5Ca0.5Mn1- x Cr x O3 (0.015?x?0.5) samples were investigated under pressures up to 11 kbar. For x=0.015 and 0.03 samples, an applied pressure enhances significantly the Curie temperature (dT C/dP?2 K/kbar), enhances the ferromagnetic phase volume below T C, and narrows appreciably the hysteresis in the vicinity of T C. For x=0.2 and 0.5 samples, pressure does not affect practically the magnetic transition temperature, but reduces noticeably the magnetization in a wide temperature range. Observed phenomena for x=0.015 and 0.03 samples are related to the interfacial elastic energy at the interface of different magnetic phases and to the suppression of the Jahn-Teller distortions under pressure. For higher doped samples, pressure possibly increases antiferromagnetic interactions between Cr3+ and Mn4+ ions

383

Ionic liquid-modified magnetic polymeric microspheres as dispersive solid phase extraction adsorbent: a separation strategy applied to the screening of sulfamonomethoxine and sulfachloropyrazine from urine.  

Science.gov (United States)

Ionic liquid-modified magnetic polymeric microspheres (ILMPM) were prepared based on Fe3O4 magnetic nanoparticles (MNPs) and ionic liquids (ILs) incorporated into a polymer. The composites were characterized using scanning electron microscopy, Fourier transform infrared analysis, thermogravimetric analysis, X-ray diffraction, and vibrating magnetometer, which indicated that ILMPM had a regularly spherical shape and strong magnetic property. The obtained ILMPM were successfully applied as a special adsorbent of magnetic dispersive solid phase extraction (MDSPE) for the rapid extraction and isolation of sulfamonomethoxine sodium and sulfachloropyrazine sodium in urine. The factors that affected extraction efficiency, such as adsorption conditions, desorption conditions, washing and elution solvents, and pH of the sample solution, were optimized. Under the optimum condition, good linearity in the range of 0.005-2.0 ?g g(-1) (r???0.9996) was obtained for the two sulfonamides (SAs); the average recoveries at three spiked levels ranged from 86.9 to 102.1 %, with relative standard deviations of ?4.3 %. The presented ILMPM-MDSPE method combined the advantages of ILs, MNPs, and MDSPE and therefore could be potentially applied for rapid screening of SAs in urine. PMID:24573579

Yan, Hongyuan; Gao, Mengmeng; Yang, Chen; Qiu, Mande

2014-04-01

384

Gas separating  

Science.gov (United States)

Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

Gollan, Arye Z. [Newton, MA

1990-12-25

385

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.

386

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

Science.gov (United States)

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 (1)H NMR. The extracted ion chromatogram (XIC) and (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. PMID:19110097

Dai, Dongmei; He, Jiuming; Sun, Ruixiang; Zhang, Ruiping; Aisa, Haji Akber; Abliz, Zeper

2009-01-26

387

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

388

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

389

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

390

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

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

Using frequency labeled exchange transfer (FLEX) to separate out conventional magnetization transfer effects from exchange transfer effects when detecting paraCEST agents  

OpenAIRE

Paramagnetic chemical exchange saturation transfer (paraCEST) agents combine the benefits of a large chemical shift difference and a fast exchange rate for sensitive MRI detection. However, the in vivo detection of these agents is hampered by the need for high B1 fields to allow sufficiently fast saturation before exchange occurs, thus causing interference of large magnetization transfer (MT) effects from semi-solid macromolecules. A recently developed approach named frequency labeled exchang...

Lin, Chien-yuan; Yadav, Nirbhay N.; Friedman, Joshua I.; Ratnakar, James; Sherry, A. Dean; Zijl, Peter C. M.

2012-01-01

393

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

394

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

395

Isotope separation  

International Nuclear Information System (INIS)

sup(195m)Au for medical usage is separated from sup(195m)Hg in a solution containing ions of sup(195m)Hg by contacting the solution with an adsorbing agent to adsorb 195Hgsup(H) thereon, followed by selective elution of sup(195m)Au generated by radioactive decay of the sup(195m)Hg. The adsorbing agent comprises a composite material in the form of an inert porous inorganic substrate (e.g. Kieselguhr),the pores of which are occupied by a hydrogel of a polysaccharide (e.g. agarose) carrying terminal thiol groups for binding Hgsup(H) ions. (author)

396

Isotope separation  

International Nuclear Information System (INIS)

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

397

Phase separation, ferromagnetism and magnetic irreversibility in La{sub 1-x}Sr{sub x}Mn{sub 1-y}Fe{sub y}O{sub 3}  

Energy Technology Data Exchange (ETDEWEB)

Magnetic susceptibility, {chi}(T), is investigated in ceramic La{sub 1-x}Sr{sub x}Mn{sub 1-y}Fe{sub y}O{sub 3} (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, {chi}(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 {chi}{sup -1}(T){approx}(T/T{sub C}-1){sup {gamma}} in the region of the FM transition is characterized by influence of two different magnetic systems, a 3D percolative one with {gamma}{sub =}{gamma}{sub p}{approx}1.8 and T{sub C}=T{sub C}{sup (p)}, and a non-percolative 3D Heisenberg spin system, with {gamma}={gamma}{sub H}{approx}1.4 and T{sub C}=T{sub C}{sup (H)}, where T{sub C}{sup (p)}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 La{sub 1-x}Sr{sub x}Mn{sub 1-y}Fe{sub y}O{sub 3} 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.

Zakhvalinskii, V.S. [Department of Mathematics and Physics, Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Department of Physics, Belgorod State University, RUS-308015 Belgorod (Russian Federation); Laiho, R. [Wihuri Physical Laboratory, University of Turku, FIN-20014 Turku (Finland); Lashkul, A.V. [Department of Mathematics and Physics, Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Lisunov, K.G. [Department of Mathematics and Physics, Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Institute of Applied Physics ASM, Academiei Str. 5, MD-2028 Kishinev (Moldova, Republic of); Laehderanta, E., E-mail: Erkki.Lahderanta@lut.fi [Department of Mathematics and Physics, Lappeenranta University of Technology, PO Box 20, FIN-53851 Lappeenranta (Finland); Nekrasova, Yu.S. [Department of Physics, Belgorod State University, RUS-308015 Belgorod (Russian Federation); Petrenko, P.A. [Institute of Applied Physics ASM, Academiei Str. 5, MD-2028 Kishinev (Moldova, Republic of)

2011-08-15

398

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-06-15

399

Particle separation  

Science.gov (United States)

Embodiments of a method for selecting particles, such as based on their morphology, is disclosed. In a particular example, the particles are charged and acquire different amounts of charge, or have different charge distributions, based on their morphology. The particles are then sorted based on their flow properties. In a specific example, the particles are sorted using a differential mobility analyzer, which sorts particles, at least in part, based on their electrical mobility. Given a population of particles with similar electrical mobilities, the disclosed process can be used to sort particles based on the net charge carried by the particle, and thus, given the relationship between charge and morphology, separate the particles based on their morphology.

Moosmuller, Hans (Reno, NV); Chakrabarty, Rajan K. (Reno, NV); Arnott, W. Patrick (Reno, NV)

2011-04-26

400

Separation of vinca alkaloid enantiomers by capillary electrophoresis applying cyclodextrin derivatives and characterization of cyclodextrin complexes by nuclear magnetic resonance spectroscopy.  

Science.gov (United States)

In this work, the enantiomeric separation of three vinca alkaloid enantiomers (vincamine, vinpocetine and vincadifformine) has been investigated in an aqueous capillary electrophoresis (CE) system using cyclodextrins (CDs). The investigated CDs were the native alpha-, beta-, and gamma-CDs and their hydroxypropylated, randomly methylated, carboxymethylated and sulfobutylated derivatives. The first part of this study consisted of the determination of the apparent averaged complex stability constants with the selected CDs. Several parameters, such as the nature and the concentration of the CD, were studied and were found to have a significant effect on the enantiomeric resolution for all studied compounds. All three vinca alkaloids were successfully enantioseparated with CDs where different migration orders were observed in case of several CDs depending on the cavity size or substituent of the host. Chiral separation and determination of the stability constants were also performed with NMR spectroscopy which confirmed the CE results. Averaged stoichiometries of the complexes were determined using the Job plot method resulting in a 1:1 complex irrespective of the alkaloid enantiomers or cyclodextrin derivative. The structures of the inclusion complexes were elucidated using 2D ROESY NMR spectroscopy. On the basis of NMR results reversal of enantiomer migration order was clarified in various cases. PMID:20724093

Sohajda, Tamás; Varga, Erzsébet; Iványi, Róbert; Fejos, Ida; Szente, Lajos; Noszál, Béla; Béni, Szabolcs

2010-12-15