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1

High gradient magnetic separation: Theory versus experiment  

Microsoft Academic Search

The experimental performance of a high gradient magnetic separator has been previously reported by other workers in some detail for a CuO\\/Al2O3slurry. Less detailed results were also reported for slurries of Mn2O3, Al, and ?-Fe2O3particles with Al2O3representing a 20:1 range in particle sizes and a 200:1 range in magnetic susceptibility. Examination of these results indicates that many layers of particles

F. Luborsky; B. Drummond

1975-01-01

2

High gradient magnetic separation theory and applications  

Microsoft Academic Search

This paper discusses key technical and economical achievements which have extended the range of application of magnetic separation methods into the commercial processing of micron size feebly magnetic materials. Commercial application of magnetic methods in the cleaning of kaolin clay is reviewed and a discussion of magnetic separation principles is given with emphasis on identification and utilization of important process

R. Oder

1976-01-01

3

Microfluidic high gradient magnetic cell separation  

Microsoft Academic Search

Separation of blood cells by native susceptibility and by the selective attachment of magnetic beads has recently been demonstrated on microfluidic devices. We discuss the basic principles of how forces are generated via the magnetic susceptibility of an object and how microfluidics can be combined with micron-scale magnetic field gradients to greatly enhance in principle the fractionating power of magnetic

David W. Inglis; Robert Riehn; James C. Sturm; Robert H. Austin

2006-01-01

4

MAGNETITE RECOVERY IN COAL WASHING BY HIGH GRADIENT MAGNETIC SEPARATION  

EPA Science Inventory

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...

5

Capture of metallic copper by high gradient magnetic separation system  

Microsoft Academic Search

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

P. K. Andy Hong

2011-01-01

6

Capture of metallic copper by high gradient magnetic separation system.  

PubMed

Valence copper was recovered from wastewater by chemical reduction and use of a high gradient magnetic separation (HGMS) system. Ammonia (NH3) and sodium dithionate (Na2S2O4) at a molar ratio of [Cu]:[NH3]:[Na2S2O4] = 1:4:3 at pH = 9.5 were used first to chemically reduce copper ion to metallic copper; the resultant metal solids were captured in an upflowing reactor space equipped with a permalloy matrix net under a high gradient magnetic field. The captured solids were predominantly 6-20 microm in diameter, with Cu2O and CuO present among the solids. Four treatment configurations with and without the use of magnetic field and metal alloy as the matrix net were tested and their effects evaluated: (1) no magnetic field or matrix, (2) no magnetic field but with matrix, (3) with magnetic field but no matrix, (4) with both magnetic field and matrix. At flow rates of 40, 60, 80 and 100 cm3/min, capture efficiencies for metallic copper in the absence of magnetic field were 87%, 86%, 63%, and 39%, respectively, and in the presence of magnetic field were 99%, 98%, 95%, and 93%, respectively. The HGMS was critical for a high capture efficiency, whereas a matrix net only marginally enhanced it. Additional tests with a larger reactor confirmed similarly high efficiencies of > 85%. The use of an alloy matrix appeared to be important when high flow rates are most likely to be employed in practical applications. PMID:22329132

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

2011-10-01

7

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

8

Technical Performance Comparison of Coal-Pyrite Flotation and High-Gradient Magnetic Separation.  

National Technical Information Service (NTIS)

The Coal Preparation Division of the Pittsburgh Mining Technology Center conducted an investigation to assess and compare the pyritic sulfur reduction potential of coal-pyrite flotation and high-gradient magnetic separation (HGMS). Tests were run on three...

R. E. Hucko K. J. Miller

1980-01-01

9

HIGH-GRADIENT MAGNETIC SEPARATION FOR REMOVAL OF SULFUR FROM COAL  

EPA Science Inventory

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

10

High gradient magnetic separation I: The removal of solids from shale oils  

Microsoft Academic Search

High gradient magnetic separations are effective in the removal of solid particles from shale oil streams. Several types of shale oils were studied that included a wide range of physical properties and retorting conditions. In order to optimize separator performance, the effects of flow velocity and temperature on solids removal were determined. A measure of separator capacity was obtained. Preliminary

K. M. Jeong; L. Petrakis; M. Takayasu; F. Friedlaender

1982-01-01

11

Magnetic separation of FCC equilibrium catalyst by HGMS. [Fluid catalytic cracking (FCC); high gradient magnetic separator (HGMS)  

Microsoft Academic Search

The results of a study on the magnetic separation of a fluid catalytic cracking catalysts by a high gradient magnetic separator are presented. Seven nickel-impregnated catalysts (Ni content ranged from 0.0 to 4.45 wt.%) were mixed in equal amounts as a model sample. The velocity effect of carrier gas is detailed with the magnetic yield and magnetic susceptibility plotted against

S. Takase; M. Ushio; Y. Oishi; T. Morita; T. Shiori

1982-01-01

12

Pulverized coal beneficiation by dry type high gradient magnetic separation process  

Microsoft Academic Search

A novel dry type high gradient magnetic separation (HGMS) device comprising a fluidizing bed is studied for the purpose of the pulverized coal ice is examined related to powder size, gas velocity, amount of feed, processing time, wire size and repeated process. Chinese Coal in the size range of 44 and 297 ..mu..m in diameter with high magnetic susceptibility compared

T. Oda; Y. Kunisue; S. Masuda

1983-01-01

13

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

Microsoft Academic Search

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

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

2010-01-01

14

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

15

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

16

APPLICATION OF HIGH-GRADIENT MAGNETIC SEPARATION TO FINE PARTICLE CONTROL  

EPA Science Inventory

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

17

High gradient magnetic separation; I: the removal of solids from shale oils  

SciTech Connect

High gradient magnetic separations are effective in the removal of solid particles from shale oil streams. Several types of shale oils were studied that included a wide range of physical properties and retorting conditions. In order to optimize separator performance, the effects of flow velocity and temperature on solids removal were determined. A measure of separator capacity was obtained. Preliminary solids characterization data are also discussed.

Jeong, K.M.; Friedlaender, F.J.; Petrakis, L.; Takayasu, M.

1982-11-01

18

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

NASA Astrophysics Data System (ADS)

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

Hayashi, S.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2011-11-01

19

Continuous Separation of Dry Crushed Coal at One Ton Per Hour by High-Gradient Magnetic Separation.  

National Technical Information Service (NTIS)

An earlier experimental program tested the separation of pyritic sulfur and ash-forming minerals from dry crushed coal in a small, cyclic, high-gradient magnetic separator over a range of each of the process parameters. That experimental program defined a...

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

1981-01-01

20

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

NASA Astrophysics Data System (ADS)

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

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

1981-12-01

21

HIGH GRADIENT MAGNETIC PARTICULATE COLLECTION  

EPA Science Inventory

This paper describes the initial phases of an evaluation of high gradient magnetic separation (HGMS) as a potential method of fine particle collection from industrial stack gases. HGMS is a relatively new separation technique that has been shown to be capable of removing small, w...

22

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

PubMed

To find new approaches to devise technologies for handling with eutrophication of inland waters is a global challenge. Separation of the P from water under conditions of continuous flow is proposed as an alternative and effective method. This work is based on using highly magnetic particles as the seeding adsorbent material and their later removal from solution by High Gradient Magnetic Separation (HGMS). Contrast to other methods based on batch conditions, large volumes of water can be easily handled by HGMS because of decreasing retention times. This study identifies the best working conditions for removing P from solution by investigating the effects of a set of four different experimental variables: sonication time, flow rate (as it determines the retention time of particles in the magnetic field), magnetic field strength and the iron (Fe) particles/P concentration ratio. Additionally, the change of P removal efficiency with time (build up effect) and the possibility of reusing magnetic particles were also studied. Our results evidenced that while flow rate does not significantly affect P removal efficiency in the range 0.08-0.36 mL s(-1), sonication time, magnetic field strength and the Fe particles/P concentration ratio are the main factors controlling magnetic separation process. PMID:21255924

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

2011-02-28

23

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

NASA Astrophysics Data System (ADS)

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

Ravnik, J.; Hriberšek, M.

2013-04-01

24

Heavy medium recovery in coal washing by continuous high gradient magnetic separation. Final report  

SciTech Connect

We have adapted high grade magnetic separation (HGMS) for magnetite recovery because of its insensitivity to coal/magnetite ratio and slurry density and its ability to capture fine magnetite at high velocity. An open vertical matrix able to capture 10 ..mu..m (avg. size) magnetite without entraining 2 mm coal has been incorporated in a 1.85 m diameter continuous high gradient magnetic separator. Three-quarter ton samples of magnetite (in 1000 gallons of water) have been recovered with the matrix ring turning at 40 cm/s through a field of 6 kOe. A laminated core demagnetizing coil followed by water sprays removes the recovered magnetite. The recovery is high, particularly for two passes which could be accomplished by two magnet heads on a single carousel ring. Coal entrainment is low for a wide range of operating conditions. A 4.8 m diameter separator, the largest currently available, with multiple heads, should be able to treat 350 tons of magnetite and coal per hour. 29 references, 52 figures, 13 tables.

Kelland, D.R.

1983-09-01

25

Chemical interferences when using high gradient magnetic separation for phosphate removal: consequences for lake restoration.  

PubMed

A promising method for lake restoration is the treatment of lake inlets through the specific adsorption of phosphate (P) on strongly magnetizable particles (Fe) and their subsequent removal using in-flow high gradient magnetic separation (HGMS) techniques. In this work, we report an extensive investigation on the chemical interferences affecting P removal efficiencies in natural waters from 20 Mediterranean ponds and reservoirs. A set of three treatments were considered based on different Fe particles/P concentration ratios. High P removal efficiencies (>80%) were found in freshwater lakes (conductivities<600 ? S cm(-1)). However, a significant reduction in P removal was observed for extremely high mineralized waters. Correlation analysis showed that major cations (Mg(2+), Na(+) and K(+)) and anions (SO(4)(2-) and Cl(-)) played an essential role in P removal efficiency. Comparison between different treatments have shown that when increasing P and Fe concentrations at the same rate or when increasing Fe concentrations for a fixed P concentration, there exist systematic reductions in the slope of the regression lines relating P removal efficiency and the concentration of different chemical variables. These results evidence a general reduction in the chemical competition between P and other ions for adsorption sites on Fe particles. Additional analyses also revealed a reduction in water color, dissolved organic carbon (DOC) and reactive silicate (Si) concentrations with the addition of Fe microparticles. PMID:21741173

de Vicente, I; Merino-Martos, A; Guerrero, F; Amores, V; de Vicente, J

2011-09-15

26

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

NASA Astrophysics Data System (ADS)

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

Senkawa, K.; Nakai, Y.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2011-11-01

27

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

NASA Astrophysics Data System (ADS)

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

Hayashi, S.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2010-11-01

28

Heavy Medium Recovery in Coal Washing by Continuous High Gradient Magnetic Separation. Final Report.  

National Technical Information Service (NTIS)

We have adapted high grade magnetic separation (HGMS) for magnetite recovery because of its insensitivity to coal/magnetite ratio and slurry density and its ability to capture fine magnetite at high velocity. An open vertical matrix able to capture 10 mu ...

D. R. Kelland

1983-01-01

29

Compact High Gradient Pulsed Magnetic Quadrupole.  

National Technical Information Service (NTIS)

A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Conductor angles are determined by a method of direct multipole elimination which theor...

D. Shuman A. Faltens Y. Kajiyama M. Kireeff-Covo P. Seidl

2005-01-01

30

Paramagnetic microchip for high-gradient separation of blood cell  

NASA Astrophysics Data System (ADS)

This paper presents a magnetophoretic separation method on a chip of white blood cells from blood under continuous flow. The separation of red blood cells from the whole blood is performed using a high gradient magnetic separation method under continuous flow to trap the particles inside the device. The device is fabricated by microfabrication technology and enables to capture the red blood cells without the use of labelling tecniques such as magnetic beads. The method consists of flowing diluted whole blood through a microfluidic channel where a ferromagnetic layer, subjected to a permanent magnetic field, is located. The majority of red blood cells are trapped at the bottom of the device while the rest of the blood is collected at the outlet. Experimental results show that an average of 95% of red blood cells are trapped in the device.

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

2008-12-01

31

A Compact High Gradient Pulsed Magnetic Quadpole  

SciTech Connect

A design for a high gradient, low inductance pulsed quadrupole magnet is presented. The magnet is a circular current dominated design with a circular iron return yoke. Conductor angles are determined by a method of direct multipole elimination which theoretically eliminates the first four higher order multipole field components. Coils are fabricated from solid round film-insulated conductor, wound as a single layer ''non-spiral bedstead'' coil having a diagonal leadout entirely within one upturned end. The coils are wound and stretched straight in a special winder, then bent in simple fixtures to form the upturned ends.

Shuman, D.; Faltens, A.; Kajiyama, Y.; Kireeff-Covo, M.; Seidl, P.

2005-07-05

32

Magnetite recovery in coal washing by high-gradient magnetic separation. Quarterly project status report, 12th quarter  

SciTech Connect

We have concentrated on running the 1.85 m carousel separator during this quarter. Some equipment refinements and personnel changes have contributed to very satisfactory results especially in coal entrainment and the ability to run at high slurry density. The carousel appears to be operating satisfactorily in its present configuration. Modification to the pole pieces, while they would help a great deal, would interrupt the program for at least several months. A new feed system has made such modifications unnecessary for the moment and we are now able to define the rest of the program to be performed under the present contract. About 35 runs have been made up to now with 40 more now scheduled.

Not Available

1982-01-01

33

Microwave enhanced high gradient magnetic desulfurization of coal  

SciTech Connect

This project consisted of several related lines of investigation, all leading toward the goal of improving the performance of high gradient magnetic separation (HGMS) in removing pyritic sulfur from eastern coals. The concept was to hear the pyrite included in coal, converting it to a more magnetic mineral form thus making more complete its removal by HGMS. The mechanism chosen was microwave irradiation. HGMS high magnetic fields and a high power microwave source was employed. We doubled the power density near the end of the project by halving the waveguide height. The magnetic properties of the coal minerals were studied by magnetometry and their chemical structure by Moessbauer spectroscopy, SEM and electron microprobe. Optical reflectance measurements, BTU and sulfur determinations were also made. We began with HGMS on whole coal samples: Upper Freeport, Pittsburgh and Illinois {number sign}6. Some were irradiated with microwaves up to 6 kW and others were retained as controls. We also measured the magnetization of pure mineral pyrite after direct contact heating. An extensive study of the microwave configuration in the waveguide was carried out at low power including the effect of having coal in the cavity. Finally, whole coal samples were subjected to microwave pretreatment in several atmospheres. In addition, a new technique of continuous axial HGMS was used to separate some constructed coal samples simply to demonstrate its possible application to improved coal desulfurization with magnetically enhanced coal pyrite. 108 refs., 160 figs., 12 tabs.

Kelland, D.R. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Francis Bitter National Magnet Lab.)

1988-10-01

34

Development of high gradient magnetic filter with evaporative cooling system  

Microsoft Academic Search

A prototype of high gradient magnetic filter is designed and fabricated, and the electrical coils, which generate a 1 Tesla background magnetic field, are cooled by evaporative cooling system. The operating magnetic flux density distribution is computed carefully by magnetic circuit method and finite element method, and the operating temperature distribution of electrical coils is computed too by finite element

Fuchuan Song; Jiayi Yuan; Xindong Tian; Guobiao Gu

2008-01-01

35

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

NASA Astrophysics Data System (ADS)

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

Krogh, T. E.

1982-04-01

36

Nuclear power reactor applications of high gradient magnetic filtration  

Microsoft Academic Search

This paper reviews the present status and future prospects for applications of high gradient magnetic filters to water-cooled nuclear power plants. A brief summary of tests performed at installations world-wide in support of nuclear applications and specifically the author's work at the United States Department of Energy's N Reactor is presented. Filtration of both the primary and secondary coolant circuits

B. Emory

1982-01-01

37

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

DOEpatents

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

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

1980-01-01

38

Immunomagnetic separation of Cryptosporidium parvum oocysts using MACS MicroBeads and high gradient separation columns  

Microsoft Academic Search

We evaluated the MACS immunomagnetic separation (IMS) system for concentrating Cryptosporidium parvum. Oocysts were first labeled with fluorescein isothiocyanate (FITC) or rabbit anti-C. parvum antibodies, then linked to MicroBeads coated with anti-FITC or anti-rabbit IgG, and separated through a high gradient separation column. Results indicated that over 95% of oocysts were recovered and their fluorescence and infectivity were retained. The

Ming Qi Deng; Kenneth M Lam; Dean O Cliver

2000-01-01

39

Ion imaging in a high-gradient magnetic guide  

SciTech Connect

We study a photoionization method to detect and image a narrow beam of cold atoms traveling along a high-gradient two-wire magnetic guide that is continuously on. Ions are accelerated in a compact acceleration region, directed through a drift region several centimeters in length, and detected using a position-sensitive ion detector. The potentials of several electrodes can be varied to adjust the imaging properties. Using ion trajectory simulations as well as experiments, we study the passage of the ions through the detection system, the magnification of the detection system, and the time-of-flight characteristics.

Vaidya, V. D. [JQI, University of Maryland, College Park, Maryland 20742 (United States); Traxler, M.; Mhaskar, R. R.; Raithel, G. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hempel, C. [Institute for Quantum Optics and Quantum Information, Innsbruck A-6020 (Austria)

2010-04-15

40

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

PubMed

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

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

2012-11-27

41

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

PubMed

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

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

2013-06-01

42

High and ultra-high gradient quadrupole magnets  

NASA Astrophysics Data System (ADS)

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

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

1985-05-01

43

Some effects of high- gradient magnetic field on tropism of roots of higher plants  

Microsoft Academic Search

The perception of gravity in living organisms is mostly based on the response of the gravisensing system to displacement of some specific mass caused by gravitational force. According to the starch-statolith hypothesis the amyloplasts play the role of specific mass in gravisensing cells of higher plants. Kuznetsov & Hasenstein (1996) have demonstrated that the high-gradient magnetic field (HGMF) exerts a

A. Kondrachuk; N. Belyavskaya

2004-01-01

44

Particle separation in a flowing suspension subject to high-gradient strong electric fields  

NASA Astrophysics Data System (ADS)

During the past decade many new techniques have been created which use a combination of electric and hydrodynamic effects to separate fine particles, droplets, and bubbles from a fluid. We will present results of our recent theoretical and experimental studies of two main phenomena, specifically, electric-field-induced aggregation and dielectrophoresis in colloids, which form the basis for electro-separation in a flowing suspension subjected to a high-gradient strong AC field. The electric-field-induced aggregation in colloids is a reversible phase transition from a homogeneous random arrangement of particles into a variety of ordered aggregation patterns caused by the interparticle interactions due to their polarization in an applied field. Dielectrophoresis is a translational motion of an electrically uncharged particle under the action of a gradient electric field due to the particle polarization. This work was supported in part by grants from the National Science Foundation (CTS-974475), the National Aeronautics and Space Administration (NCC3-607), and the Office of Naval Research (N00014-99-1-0473).

Acrivos, Andreas; Khusid, Boris

1999-11-01

45

Magnetic separation for soil decontamination  

SciTech Connect

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

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

1993-02-01

46

Magnetic separation for soil decontamination  

SciTech Connect

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

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

1993-01-01

47

Numerical study of magnetic nanoparticles concentration in biofluid (blood) under influence of high gradient magnetic field  

NASA Astrophysics Data System (ADS)

Ferrofluids are widely used in pharmaceutical industries as magnetic separation tools, anti-cancer drug carriers and micro-valve applications. The purpose of the current study is to investigate the effect of a magnetic field on the volume concentration of magnetic nanoparticles of a non-Newtonian biofluid (blood) as a drug carrier. The effect of particles on the flow field is considered. The governing non-linear differential equations, concentration and Naviar-stokes are coupled with the magnetic field. To solve these equations, a finite volume based code is developed and utilized. The results show accumulation of magnetic nanoparticles near the magnetic source until it looks like a solid object. The accumulation of nanoparticles is due to the magnetic force that overcomes the fluid drag force. As the magnetic strength and size of the magnetic particles increase, the accumulation of nanoparticles increases, as well. The magnetic susceptibility of particles also affects the flow field and the contour of the concentration considerably.

Reza Habibi, Mohammad; Ghasemi, Majid

2011-01-01

48

High gradient magnetic separation: Effect of temperature on performance  

Microsoft Academic Search

A simple model is formulated to determine the effect of temperature on the filtering ability of HGMS devices. An optimum temperature range is observed to exist for which the capture of ash-forming minerals and inorganic sulfur in liquid coal is at a maximum. Model will serve as a framework for analyzing experimental data in future. In the past, some pertinent,

I. Y. Akoto; Francis Bitter

1976-01-01

49

Guiding of Rydberg atoms in a high-gradient magnetic guide  

NASA Astrophysics Data System (ADS)

We study the guiding of 87Rb 59D5/2 Rydberg atoms in a linear, high-gradient, two-wire magnetic guide. Time-delayed microwave ionization and ion detection are used to probe the Rydberg atom motion. We observe guiding of Rydberg atoms over a period of 5 ms following excitation. The decay time of the guided-atom signal is about five times that of the initial state. We attribute the lifetime increase to an initial phase of l-changing collisions and thermally induced Rydberg-Rydberg transitions. Detailed simulations of Rydberg-atom guiding reproduce most experimental observations and offer insight into the internal-state evolution.

Traxler, M.; Sapiro, R. E.; Hempel, C.; Lundquist, K.; Power, E. P.; Raithel, G.

2012-08-01

50

Hybrid magnet devices for molecule manipulation and small scale high gradient-field applications  

DOEpatents

The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetizable molecular structures and targets. Also disclosed are hybrid magnetic tweezers able to exert approximately 1 nN of force to 4.5 .mu.m magnetic bead. The maximum force was experimentally measured to be .about.900 pN which is in good agreement with theoretical estimations and other measurements. In addition, a new analysis scheme that permits fast real-time position measurement in typical geometry of magnetic tweezers has been developed and described in detail.

Humphries, David E. (El Cerrito, CA); Hong, Seok-Cheol (Seoul, KR); Cozzarelli, legal representative, Linda A. (Berkeley, CA); Pollard, Martin J. (El Cerrito, CA); Cozzarelli, Nicholas R. (Berkeley, CA)

2009-01-06

51

Particle separation in a flowing suspension subject to high-gradient strong electric fields  

Microsoft Academic Search

During the past decade many new techniques have been created which use a combination of electric and hydrodynamic effects to separate fine particles, droplets, and bubbles from a fluid. We will present results of our recent theoretical and experimental studies of two main phenomena, specifically, electric-field-induced aggregation and dielectrophoresis in colloids, which form the basis for electro-separation in a flowing

Andreas Acrivos; Boris Khusid

1999-01-01

52

Modulation of monocytic leukemia cell function and survival by high gradient magnetic fields and mathematical modeling studies.  

PubMed

The influence of spatially modulated high gradient magnetic fields on cellular functions of human THP-1 leukemia cells is studied. We demonstrate that arrays of high-gradient micrometer-sized magnets induce i) cell swelling, ii) prolonged increased ROS production, and iii) inhibit cell proliferation, and iv) elicit apoptosis of THP-1 monocytic leukemia cells in the absence of chemical or biological agents. Mathematical modeling indicates that mechanical stress exerted on the cells by high magnetic gradient forces is responsible for triggering cell swelling and formation of reactive oxygen species followed by apoptosis. We discuss physical aspects of controlling cell functions by focused magnetic gradient forces, i.e. by a noninvasive and nondestructive physical approach. PMID:24439412

Zablotskii, Vitalii; Syrovets, Tatiana; Schmidt, Zoe W; Dejneka, Alexandr; Simmet, Thomas

2014-03-01

53

Superparamagnetic Cation–Exchange Adsorbents for Bioproduct Recovery from Crude Process Liquors by High?Gradient Magnetic Fishing  

Microsoft Academic Search

Different routes were screened for the preparation of superparamagnetic cation–exchange adsorbents for the capture of proteins using high?gradient magnetic fishing. Starting from a polyglutaraldehyde?coated base particle, the most successful of these involved attachment of sulphite to oligomers of epichlorohydrin formed on the particle surface. The resultant cation?exchanger had a maximum lysozyme binding capacity of 272 mg g and a dissociation constant of

Sune F. L. Justesen; Timothy J. Hobley; Owen R. T. Thomas

2004-01-01

54

Spatial fractionation of paramagnetic particles precipitating in a high-gradient magnetic field of a short magnetized cylinder  

NASA Astrophysics Data System (ADS)

The motion of dia- and paramagnetic particles precipitating in a liquid near a vertical magnetized cylinder of finite length in a plane transverse to the direction of magnetization has been studied, the phenomenon of spatial separation of paramagnetic particles by the value of magnetic susceptibility is described, and a comparison of the efficiency of separation of paramagnetic particles in the fields of a short cylinder and a sphere has been carried out.

Zholud', A. M.

2010-11-01

55

Magnetic Separation Device.  

National Technical Information Service (NTIS)

This invention pertains to magnetic separation devices and more particularly to; magnetic separation devices used to selectively remove magnetic bead-coated cells from tissues such as bone marrow or blood. Depletion of cell populations from boner marrow h...

G. M. Starken J. Cavin R. A. Quinnell C. A. Twigg D. P. Crawford

1985-01-01

56

Magnetic separation for environmental remediation  

SciTech Connect

High Gradient Magnetic Separation (HGMS) is a form of magnetic separation used to separate solids from other solids, liquids or gases. HGMS uses large magnetic field gradients to separate ferromagnetic and paramagnetic particles from diamagnetic host materials. The technology relies only on physical properties, and therefore separations can be achieved while producing a minimum of secondary waste. Actinide and fission product wastes within the DOE weapons complex pose challenging problems for environmental remediation. Because the majority of actinide complexes and many fission products are paramagnetic, while most host materials are diamagnetic, HGMS can be used to concentrate the contaminants into a low volume waste stream. The authors are currently developing HGMS for applications to soil decontamination, liquid waste treatment, underground storage tank waste treatment, and actinide chemical processing residue concentration. Application of HGMS usually involves passing a slurry of the contaminated mixture through a magnetized volume. Field gradients are produced in the magnetized volume by a ferromagnetic matrix material, such as steel wool, expanded metal, iron shot, or nickel foam. The matrix fibers become trapping sites for ferromagnetic and paramagnetic particles in the host material. The particles with a positive susceptibility are attracted toward an increasing magnetic field gradient and can be extracted from diamagnetic particles, which react in the opposite direction, moving away from the areas of high field gradients. The extracted paramagnetic contaminants are flushed from the matrix fibers when the magnetic field is reduced to zero or when the matrix canister is removed from the magnetic field. Results are discussed for the removal of uranium trioxide from water, PuO{sub 2}, U, and Pu from various soils (Fernald, Nevada Test Site), and the waste water treatment of Pu and Am isotopes using HGMS.

Schake, A.R.; Avens, L.R.; Hill, D.D.; Padilla, D.D.; Prenger, F.C.; Romero, D.A.; Worl, L.A. [Los Alamos National Lab., NM (United States); Tolt, T.L. [Lockheed Environmental Systems and Technologies Co., Las Vegas, NV (United States)

1994-11-01

57

Magnetic measurements of the Fermilab high gradient quadrupoles for the LHC interaction regions  

Microsoft Academic Search

Three short models of the MQXB quadrupole magnet for the LHC interaction regions have been built and tested at Fermilab. In this paper we present the magnetic field measurement results and compare them with expectations based on as-built dimensional parameters and with a preliminary table of field quality requirements

R. Bossert; J. Brandt; J. DiMarco; M. J. Lamm; F. Nobrega; G. Sabbi; P. Schlabach; C. Sylvester; M. A. Tartaglia; J. C. Tompkins; A. V. Zlobin; S. Caspi

1999-01-01

58

High-gradient quadrupole magnet for a polarized-beam facility  

SciTech Connect

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

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

1980-01-01

59

High gradient superconducting quadrupoles  

SciTech Connect

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

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

1987-07-01

60

A high gradient quadrupole magnet for the SSC (Superconducting Super Collider)  

SciTech Connect

A quadrupole magnet for the SSC has been designed with a gradient of 234 T/m at 6500 A. Coil ID is 40 mm. The two-layer windings have 9 inner turns and 13 outer turns per pole with a wedge-shaped spacer in each layer. The 30-strand cable is identical to that used in the outer layer of the SSC dipole magnet. Interlocking aluminum alloy collars are compressed around the coils using a four-way press and are locked with four keys. The collared coil is supported and centered in a cold split iron yoke. A one-meter model was constructed and tested. Design details including quench behavior are presented.

Taylor, C.; Caspi, S.; Helm, M.; Mirk, K.; Peters, C.; Wandesforde, A.

1987-03-01

61

The Bloch Equations in High-Gradient Magnetic Resonance Force Microscopy: Theory and Experiment  

NASA Astrophysics Data System (ADS)

We report theory and observations of paramagnetic resonance in a measured field gradient of 44,000 T per meter by the technique of magnetic resonance force microscopy (MRFM). Resonance was induced in a dilute solid solution of diphenylpicrylhydrazyl in polystyrene at 77 and 10 K by an amplitude-modulated microwave field. This modulated the force between resonant sample spins and a micrometer-scale SmCo magnetic tip on a force microscope cantilever. The force signals were typically of order 10 fN, and were detected above a thermal noise floor of 80 aN per root hertz at 10 K, equivalent to a magnetic moment noise of 200 ? B per root hertz of bandwidth. Resonance saturation was readily observed. Starting with the Bloch equations, we derived simple analytic expressions for the predicted cantilever signal amplitudes and T1-dependent phase lags, valid at low microwave power levels. For power levels below saturation, the data were in good agreement with the Bloch equation predictions, while above saturation the measured force increased more slowly with power than predicted. Several ESR mechanisms which might lead to non-Bloch dynamics in the MRFM environment are reviewed. Spin-relaxation mechanisms are also reviewed. A detailed description of the experimental apparatus is offered.

Dougherty, W. M.; Bruland, K. J.; Chao, S. H.; Garbini, J. L.; Jensen, S. E.; Sidles, J. A.

2000-03-01

62

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

PubMed

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

63

Ligand-specific isolation of endosomes and lysosomes using superparamagnetic colloidal iron dextran glycoconjugates and high gradient magnetic affinity chromatography.  

PubMed

We have developed a ligand-specific method for the visualization, isolation, and biochemical characterization of cell surface and intracellular membranes mediating endocytic transport. Iron dextran particles (FeDex) bearing either covalently conjugated galactosyl bovine serum albumin (GalBSA/FeDex) or asialofetuin (ASF/FeDex) are bound by the asialoglycoprotein receptor (ASGP-R) of HepG2 cells and transported to lysosomes with kinetics indistinguishable from those of free GalBSA or ASF. FeDex particles, which have a 3 to 5 nm electron-dense colloidal iron core, can be visualized by electron microscopy. Following incubation of GalBSA/FeDex with HepG2 cells at 37 degrees C, FeDex particles are seen at the cell surface, in endosomes, and in lysosomes. Surface membrane and intracellular organelles bearing a sufficient number of FeDex particles can be efficiently isolated from disrupted cells by high gradient magnetic affinity chromatography (HIMAC). Plasma membranes and endosomal/lysosomal membranes isolated by HIMAC are 35 to 40-fold enriched for GalBSA/FeDex or ASF/FeDex relative to the postnuclear supernatant. Alkaline phosphodiesterase I (APDE) and galactosyltransferase are each enriched 8-fold in the plasma membrane fraction prepared by HIMAC whereas neither beta-galactosidase nor glucose-6-phosphatase are detected in this fraction. The intracellular membrane fraction, containing both endosomes and lysosomes, is enriched for galactosyltransferase and beta-galactosidase but not for APDE or glucose-6-phosphatase. Use of FeDex conjugates in conjunction with HIMAC provides an effective method for ligand-specific isolation of membranes and correlation of morphological and biochemical characteristics. PMID:1680681

Becich, M J; Baenziger, J U

1991-06-01

64

Industrial Applications of Magnetic Separation.  

National Technical Information Service (NTIS)

The conference convened to provide opportunities for researchers and practitioners to exchange the latest information on research and development in magnetic separation, emphasizing the existing and potential industrial applications of magnetic separation...

Y. A. Liu

1979-01-01

65

Field quality in Fermilab-built models of high gradient quadrupole magnets for the LHC interaction regions  

Microsoft Academic Search

Superconducting quadrupole magnets for the interaction regions of the Large Hadron Collider are being developed by the US-LHC Accelerator Project. These 70 mm bore quadrupole magnets are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T\\/m. A series of 2 m model magnets are being built and tested at Fermilab to optimize

N. Andreev; T. Arkan; P. Bauer; R. Bossert; J. Brandt; D. R. Chichili; J. Carson; J. DiMarco; S. Feher; H. Glass; J. Kerby; M. J. Lamm; A. A. Makarov; A. Nobrega; I. Novitski; T. Ogitsu; D. Orris; J. P. Ozelis; T. Peterson; R. Rabehl; W. Robotham; G. Sabbi; P. Schlabach; C. Sylvester; J. Strait; M. Tartaglia; J. C. Tompkins; S. Yadav; A. V. Zlobin; S. Caspi; D. McInturff; R. Scanlan; A. Ghosh

2000-01-01

66

Continuous magnetic separator and process  

DOEpatents

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

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

2008-04-22

67

HIGH GRADIENT INDUCTION ACCELERATOR  

SciTech Connect

A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

2007-06-21

68

High gradient directional solidification furnace  

NASA Astrophysics Data System (ADS)

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

Aldrich, B. R.; Whitt, W. D.

1985-10-01

69

High gradient directional solidification furnace  

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

70

High gradient magnetic cell sorting and internal standardisation substantially improve the assay for somatic mutations at the glycophorin A (GPA) locus  

Microsoft Academic Search

In the MACS-BR6 version of the GPA assay [Int. J. Radiat. Res. 70 (1996) 131] variant red blood cells (RBC) are isolated from 5×108 normal RBC by magnetic cell separation (MACS) before detection and quantification by immunolabelling and flow cytometry as in the classical BR6 assay. In the present work it is described how the MACS-BR6 assay is improved by

Klaus Hempel; Werner Deubel; Reinhard Lorenz; Christoph Reiners

2003-01-01

71

Magnetic Separator Enhances Treatment Possibilities  

NASA Technical Reports Server (NTRS)

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

2008-01-01

72

Droplet-based magnetically activated cell separation  

Microsoft Academic Search

In this study, we developed a method that target cells in suspension can be separated by combining magnetic force and gravitation force. Since the newly developed method involves a separating process of a droplet containing nontarget cells in suspension by applying magnetic force to separate target cells, we called it droplet-based magnetic activated cell sorting (dMACS). To demonstrate the efficiency

Y. H. Kim; S. Hong; B. Kim; S. Yun; Y. R. Kang; K. K. Paek; J. W. Lee; S. H. Lee; B. K. Ju

2004-01-01

73

Isolation of Bowman-Birk-Inhibitor from soybean extracts using novel peptide probes and high gradient magnetic separation.  

PubMed

Soybean proteins offer exceptional promise in the area of cancer prevention and treatment. Specifically, Bowman-Birk Inhibitor (BBI) has the ability to suppress carcinogenesis in vivo, which has been attributed to BBI's inhibition of serine protease (trypsin and chymotrypsin) activity. The lack of molecular probes for the isolation of this protein has made it difficult to work with, limiting its progress as a significant candidate in the treatment of cancer. This study has successfully identified a set of novel synthetic peptides targeting the BBI, and has demonstrated the ability to bind BBI in vitro. One of those probes has been covalently immobilised on superparamagnetic microbeads to allow the isolation of BBI from soy whey mixtures in a single step. Our ultimate goal is the use of the described synthetic probe to facilitate the isolation of this potentially therapeutic protein for low cost, scalable analysis and production of BBI. PMID:23442627

Fields, Conor; Mallee, Paul; Muzard, Julien; Lee, Gil U

2012-10-15

74

Magnetite recovery in coal washing by high-gradient magnetic separation. Quarterly project status report, 13th quarter  

SciTech Connect

This quarter we have made considerable progress on the list of specific experimental runs to be performed contained in the last report on August 10. To be specific, 19 out of 28 on that list for the present matrix have been performed with no more than one condition different than shown on the list. The reason for this difference is that the loading of recovered heavy mediums on the matrix has very often been higher than we predicted on the basis of the earlier batch work. In addition, 37 runs have been made to assess machine performance, correct problems or explore new ideas.

Kelland, D.R.

1982-11-10

75

Magnetic separation of antibiotics by electrochemical magnetic seeding  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

76

A magnetic separator for efficient microalgae harvesting.  

PubMed

A magnetic separator, which consisted of permanent magnet drum, separation chamber and scraper blade, was manufactured for efficient microalgae harvesting. The harvesting efficiency of Chlorella ellipsoidea cells reached more than 95% within forty seconds in each batch operation of microalgae harvesting. In the continuous operation of microalgae harvesting, the harvesting efficiency decreased with increasing the liquid flow rate through the separation chamber and remained more than 95% at the liquid flow rate less than 100mL/min. The developed magnetic separator together with functional magnetic nanoparticles provided a promising method for efficient microalgae harvesting in practice. PMID:24656619

Hu, Yi-Ru; Guo, Chen; Xu, Ling; Wang, Feng; Wang, Shi-Kai; Hu, Zanmin; Liu, Chun-Zhao

2014-04-01

77

Magnetic nanoparticles separation based on nanostructures  

Microsoft Academic Search

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

Jianfei Sun; Rui Xu; Yu Zhang; Ming Ma; Ning Gu

2007-01-01

78

Magnetic nanoparticles separation based on nanostructures  

NASA Astrophysics Data System (ADS)

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

Sun, Jianfei; Xu, Rui; Zhang, Yu; Ma, Ming; Gu, Ning

2007-05-01

79

Magnetic Cell Separation with Electrodeposited Nanowires  

Microsoft Academic Search

Ferromagnetic nanowires are demonstrated as an effective tool to apply magnetic forces to cells. The nanowires are made by electrochemical deposition in nanoporous templates, permitting detailed control of their morphology, magnetic properties, and composition. In addition, the nanowires can be functionalized with biologically active molecules based on their surface chemistry. Magnetic cell separations were performed with Ni nanowires 350 nm

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

2003-01-01

80

A PURPOSE ORIENTED MAGNETIC SEPARATOR: SKIMMER  

SciTech Connect

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

Salih Ersayin

2005-08-09

81

High Gradient Operation with the CEBAF Upgrade RF Control System.  

National Technical Information Service (NTIS)

The CEBAF Accelerator at Jefferson Lab is presently a 6 GeV five pass electron accelerator consisting of two superconducting linacs joined by independent magnetic transport arcs. Energy will be upgraded to 12 GeV with the addition of 10 new high gradient ...

A. Hofler C. Hovater H. Dong K. Davis L. King

2006-01-01

82

Development of magnetic separation system of magnetoliposomes  

NASA Astrophysics Data System (ADS)

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

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

2009-10-01

83

Rapid Characterization of Magnetic Moment of Cells for Magnetic Separation  

PubMed Central

NCI-H1650 lung cancer cell lines labeled with magnetic nanoparticles via the Epithelial Cell Adhesion Molecule (EpCAM) antigen were previously shown to be captured at high efficiencies by a microfabricated magnetic sifter. If fine control and optimization of the magnetic separation process is to be achieved, it is vital to be able to characterize the labeled cells’ magnetic moment rapidly. We have thus adapted a rapid prototyping method to obtain the saturation magnetic moment of these cells. This method utilizes a cross-correlation algorithm to analyze the cells’ motion in a simple fluidic channel to obtain their magnetophoretic velocity, and is effective even when the magnetic moments of cells are small. This rapid characterization is proven useful in optimizing our microfabricated magnetic sifter procedures for magnetic cell capture.

Ooi, Chinchun; Earhart, Christopher M.; Wilson, Robert J.; Wang, Shan X.

2014-01-01

84

A novel human detoxification system based on nanoscale bioengineering and magnetic separation techniques.  

PubMed

We describe the conceptual approach, theoretical background and preliminary experimental data of a proposed platform technology for specific and rapid decorporation of blood-borne toxins from humans. The technology is designed for future emergent in-field or in-hospital detoxification of large numbers of biohazard-exposed victims; for example, after radiological attacks. The proposed systems is based on nanoscale technology employing biocompatible, superparamagnetic nanospheres, which are functionalized with target-specific antitoxin receptors, and freely circulate within the human blood stream after simple intravenous injection. Sequestration of the blood-borne toxins onto the nanosphere receptors generates circulating nanosphere-toxin complexes within a short time interval; mathematical modeling indicates prevailing of unbound nanosphere receptors over target toxin concentrations at most therapeutic injection dosages. After a toxin-specific time interval nanosphere-toxin complexes are generated within the blood stream and, after simple arterial or venous access, the blood is subsequently circulated via a small catheter through a portable high gradient magnetic separator device. In this device, the magnetic toxin complexes are retained by a high gradient magnetic field and the detoxified blood is then returned back to the blood circulation (extracorporeal circulation). Our preliminary in vitro experiments demonstrate >95% first pass capture efficiency of magnetic spheres within a prototype high gradient magnetic separation device. Further, based on the synthesis of novel hydrophobic magnetite nanophases with high magnetization ( approximately 55 emu/g), the first biodegradable magnetic nanospheres at a size range of approximately 280 nm and functionalized with PEG-maleimide surface groups for specific antibody attachment are described here. In future applications, we envision this technology to be suitable for emergent, in-field usage for acutely biohazard exposed victims as both the injectable toxin-binding magnetic spheres and the separator device are made to be portable, light-weight, zero-power, and self- or helper-employed. Details of the technology are presented and the state-of-knowledge and research is discussed. PMID:17123743

Chen, Haitao; Kaminski, Michael D; Liu, Xianqiao; Mertz, Carol J; Xie, Yumei; Torno, Michael D; Rosengart, Axel J

2007-01-01

85

Magnetic Cell Separation with Electrodeposited Nanowires  

NASA Astrophysics Data System (ADS)

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

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

2003-03-01

86

Particle acceleration at a reconnecting magnetic separator  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

87

Polarized electrons from high-gradient guns  

SciTech Connect

To take advantage of the lower emittance associated with extraction fields >> 10 MV/m, a number of technological hurdles must be overcome before photocathodes appropriate for generating polarized electrons can be utilized in high-gradient guns. Both rf guns and very fast ultra-high gradient ({ge} 1 GV/m) diode guns are anticipated. The known problems--some of which may be more than just technical--are delineated, and the present status of relevant research is reviewed.

Clendenin, J.E.; Mulhollan, G.A.

1998-09-01

88

Selective Separation of Coal Feedstocks for Conversion by Magnetic Separation Techniques.  

National Technical Information Service (NTIS)

The Open-Gradient Magnetic Separation (OGMS) technique can separate particles on the basis of small differences in magnetic susceptibility. The highly reactive coal macerals are diamagnetic while the minerals and less reactive macerals range from slightly...

E. C. Hise A. S. Holman

1981-01-01

89

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

NASA Astrophysics Data System (ADS)

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

Khashan, Saud A.; Furlani, Edward P.

2013-03-01

90

Magnetic separation techniques in diagnostic microbiology.  

PubMed Central

The principles of magnetic separation aided by antibodies or other specific binding molecules have been used for isolation of specific viable whole organisms, antigens, or nucleic acids. Whereas growth on selective media may be helpful in isolation of a certain bacterial species, immunomagnetic separation (IMS) technology can isolate strains possessing specific and characteristic surface antigens. Further separation, cultivation, and identification of the isolate can be performed by traditional biochemical, immunologic, or molecular methods. PCR can be used for amplification and identification of genes of diagnostic importance for a target organism. The combination of IMS and PCR reduces the assay time to several hours while increasing both specificity and sensitivity. Use of streptavidin-coated magnetic beads for separation of amplified DNA fragments, containing both biotin and a signal molecule, has allowed for the conversion of the traditional PCR into an easy-to-read microtiter plate format. The bead-bound PCR amplicons can also easily be sequenced in an automated DNA sequencer. The latter technique makes it possible to obtain sequence data of 300 to 600 bases from 20 to 30 strains, starting with clinical samples, within 12 to 24 h. Sequence data can be used for both diagnostic and epidemiologic purposes. IMS has been demonstrated to be a useful method in diagnostic microbiology. Most recent publications describe IMS as a method for enhancing the specificity and sensitivity of other detection systems, such as PCR, and providing considerable savings in time compared with traditional diagnostic systems. The relevance to clinical diagnosis has, however, not yet been fully established for all of these new test principles. In the case of PCR, for example, the presence of specific DNA in a food sample does not demonstrate the presence of a live organism capable of inducing a disease. However, all tests offering increased sensitivity and specificity of detection, combined with reduced time of analysis, have to be seriously evaluated. Images

Olsvik, O; Popovic, T; Skjerve, E; Cudjoe, K S; Hornes, E; Ugelstad, J; Uhlen, M

1994-01-01

91

17 GHz High Gradient Accelerator Research  

SciTech Connect

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

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

2013-07-10

92

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

PubMed Central

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

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

2012-01-01

93

Research and Development for Ultra-High Gradient Accelerator Structures  

SciTech Connect

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

Tantawi, Sami G.; Dolgashev, Valery [SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, CA 94305 (United States); Higashi, Yasuo [High Energy Accelerator Research Organization, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Spataro, Bruno [INFN-LNF, 00044 Frascati (Italy)

2010-11-04

94

Research and Development for Ultra-High Gradient Accelerator Structures  

SciTech Connect

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

Tantawi, Sami G.; /SLAC; Dolgashev, Valery; /SLAC; Higashi, Yasuo; /KEK, Tsukuba; Spataro, Bruno; /Frascati

2012-06-11

95

Droplet-based Magnetically Activated Cell Separator (DMACS): Evaluation of separation efficiency versus variance of magnetic flux density  

Microsoft Academic Search

We introduced a droplet-based magnetically activated cell separator (DMACS) that utilizes a hanging droplet of microliter-sized volume for dividing positive (magnetically labeled) and negative (magnetically unlabeled) cells. It enabled us to solve adhesion problem in channel and showed better separation efficiency. However, the separation efficiency was changed under variations of initial volume (the droplet volume of cell suspension before buffer

Youngho Kim; Su Hong; Sang Ho Lee; Kyeongkap Paek; Byungkyu Kim

2006-01-01

96

High-gradient RF box cavity breakdown simulations using 3-D particle tracking code VORPAL  

Microsoft Academic Search

Researchers are designing next-generation accelerator cavities that will provide high-gradient electric fields, on the order of 50 MV\\/m, and strong magnetic fields (~3T), which are desired in the operation of muon colliders and neutrino experiments. However, the metallic breakdown processes occur in these cavities limit the possibilities of achieving such high gradient electric and strong magnetic fields. Hence it becomes

S. Mahalingam; S. A. Veitzer; P. H. Stoltz

2010-01-01

97

High-gradient continuous-casting furnace  

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

98

Selective separation of coal feedstocks for conversion by magnetic separation techniques  

Microsoft Academic Search

The Open-Gradient Magnetic Separation (OGMS) technique can separate particles on the basis of small differences in magnetic susceptibility. The highly reactive coal macerals are diamagnetic while the minerals and less reactive macerals range from slightly diamagnetic to paramagnetic with the pyritic minerals exhibiting the greatest positive magnetic susceptibility. OGMS can spread a falling stream of fine coal into a spectrum

E. C. Hise; A. S. Holman

1981-01-01

99

Railroading cells, microfluidic magnetic cell separation using ferromagnetic stripes  

Microsoft Academic Search

Magnetic cell separation has been demonstrated using recessed ferromagnetic stripes. Here we demonstrate precise control of the cell's positions using branched magnetic stripes in a microfluidic device. The technique allows magnetically separated cells to be delivered in precise locations to downstream cellular analysis components.

David Inglis; Robert Austin; James Sturm

2006-01-01

100

Relativistic klystrons for high-gradient accelerators  

SciTech Connect

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

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

1990-09-05

101

High gradient accelerators for linear light sources  

SciTech Connect

Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.

Barletta, W.A.

1988-09-26

102

Exploration of very high gradient cavities  

SciTech Connect

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

Grigory Eremeev

2011-07-01

103

Temperature and magnetic dual responsive microparticles for DNA separation  

Microsoft Academic Search

The use of solid support in DNA separation from biological mixtures for diagnostics offers great potential for developing versatile separating tools. Although different polymer materials have been developed and studied for DNA separation, the application of such non-magnetic particles for DNA separation has remained limited. In this work, we describe the adsorption and desorption behavior of DNA on the temperature

Abdelhamid Elaissari

2011-01-01

104

Fundamental study of phosphor separation by controlling magnetic force  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

105

Integrated acoustic and magnetic separation in microfluidic channels  

PubMed Central

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 108 particles?hr.

Adams, Jonathan D.; Thevoz, Patrick; Bruus, Henrik; Soh, H. Tom

2009-01-01

106

Relativistic klystron research for high gradient accelerators  

SciTech Connect

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

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

1988-06-01

107

A Continuous Throughput Micro Magnetic Cell Separator  

Microsoft Academic Search

Micro-fluidic total analysis systems for diagnosis, research and treatment require foolproof sorting and separation techniques. A bulk fluid sample invariably contains unwanted and useless matter that must be disposed of. The chip must first be able to separate the wheat from the chaff before doing any analysis. A micro-fluidic device that continuously separates blood cells from a whole blood sample

David Inglis; James C. Sturm; Robert H. Austin

2004-01-01

108

Magnetic separation of coal fly ash from Bulgarian power plants.  

PubMed

Fly ash from three coal-burning power plants in Bulgaria: 'Maritza 3', 'Republika' and 'Rousse East' were subjected to wet low-intensity magnetic separation. The tests were performed at different combinations of magnetic field intensity, flow velocity and diameter of matrix elements. It was found that all parameters investigated affected the separation efficiency, but their influence was interlinked and was determined by the properties of the material and the combination of other conditions. Among the fly ash characteristics, the most important parameters, determining the magnetic separation applicability, were mineralogical composition and distribution of minerals in particles. The main factors limiting the process were the presence of paramagnetic Fe-containing mineral and amorphous matter, and the existence of poly-mineral particles and aggregates of magnetic and non-magnetic particles. It was demonstrated that the negative effect of both factors could be considerably limited by the selection of a proper set of separation conditions. The dependences between concentration of ferromagnetic iron in the ash, their magnetic properties and magnetic fraction yields were studied. It was experimentally proved that, for a certain set of separation conditions, the yields of magnetic fractions were directly proportional to the saturation magnetization of the ferromagnetic components of the ash. The main properties of typical magnetic and non-magnetic fractions were studied. PMID:20699291

Shoumkova, Annie S

2011-10-01

109

Continuous cell separation using novel magnetic quadrupole flow sorter  

Microsoft Academic Search

A laboratory prototype of a flow cell sorter based on magnetic quadrupole field was built and evaluated. The magnetic force acting on magnetically labeled cells in such a field has a `centrifugal’ character which provides a basis for the design of a continuous separation process. The sorter was tested on a model cell system of human peripheral lymphocytes labeled with

Maciej Zborowski; Liping Sun; Lee R Moore; P Stephen Williams; Jeffrey J. Chalmers

1999-01-01

110

Magnetic separator having a multilayer matrix, method and apparatus  

DOEpatents

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

Kelland, David R. (Lexington, MA)

1980-01-01

111

Correlation of Physical Coal Separations: Part I.  

National Technical Information Service (NTIS)

Experimental separations of the inorganic material from a coal by the specific-gravity (wet), high-gradient magnetic (dry), and open-gradient magnetic (dry) processes were performed and analyzed to compare for Btu recovery vs efficiency of removal of pyri...

E. C. Hise

1979-01-01

112

Density separation of solids in ferrofluids with magnetic grids  

SciTech Connect

Nonmagnetic solids in a superparamagnetic ferrofluid are subjected to body forces proportional to the intensity of magnetization of the fluid and the gradient of the magnetic field. An apparent density of the fluid can be defined from the force equations, and since the apparent density can be much larger than the true density, it is possible to levitate or float dense objects. Mixtures of solids with a density greater than the apparent density sink while lower density solids float. In practice it is difficult to create a uniform gradient over a large volume and single gap magnetic separators require very large magnets or have a limited throughput. To overcome that problem, multiple gap magnetic grids have been designed. Such grids consist of planar arrays of parallel bars of alternating polarity, driven by permanent magnets. When immersed in ferrofluid, magnetic grids create nonuniform field gradients and apparent densities in the fluid. However, both analysis and experimental measurements show that the grid acts as a barrier to particles below a critical density, while permitting more dense particles to fall through the grid. Thus, a magnetic grid filter can be used as a high throughput binary separator of solids according to their densities. Such filters can be cascaded for more complex separations. Several magnetic grid filters have been designed, built, and tested. Magnetic measurements qualitatively agree with the theoretical predictions. Experiments with synthetic mixtures have demonstrated that good binary separations can be made.

Fay, H. (Union Carbide Corp., Tonawanda, NY); Quets, J.M.

1980-04-01

113

Microstripes for transport and separation of magnetic particles.  

PubMed

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

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

2012-06-01

114

A cascade mode magnetophoretic microseparator for high efficiency blood cell separations  

Microsoft Academic Search

This paper presents the design, fabrication, and characterization of a high efficiency blood cell separator based on a cascade design of the continuous paramagnetic capture mode magnetophoretic microseparator. The PMC cascade microseparator directly separates blood cells from whole blood based on their native magnetic properties using a high gradient magnetic field without the use of additives such as magnetic tagging

Ki-Ho Han; A. Bruno Frazier

2005-01-01

115

Cell Separation Using Protein-A-Coated Magnetic Nanoclusters  

Microsoft Academic Search

A new immunomagnetic separation process that uses protein A-coated magnetic nanoclusters (PACMAN) as the separation vehicles has been developed. The nanoclusters are produced by sonicating egg yolk phosphatidylcholine and the transmembrane Fc receptor protein-A in a buffered aqueous ferrofluid suspension. The phospholipids appear to form a coating around clusters of 5-50 magnetic nanoparticles, while some of the protein-A associate with

Srinivas V. Sonti; Arijit Bose

1995-01-01

116

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

Microsoft Academic Search

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

Hiromichi Inokuchi; Yuji Suzuki; Nobuhide Kasagi

117

A Novel Magnetic Separation Technique: Selective Separation of Ultrafine Particles by Magnetophoresis  

Microsoft Academic Search

The selective and specific extraction of species of interest from local environmental and other sample sources are important for scientific research, industrial processes, and environmental applications. A novel process for selective separation of magnetic particles using magnetophoresis is investigated. The principle of this process is that the direction and velocity of particle movement in a magnetic field gradient are determined

F. Coyne Prenger; Laura A. Worl; Michael D. Johnson; Joseph A. Waynert; Robert M. Wingo

2004-01-01

118

Physicochemical properties of magnetically separated shale oil solids  

Microsoft Academic Search

The authors present thermomagnetic and X-ray studies to show that the composition of shale oil solids magnetically separated from three different shale oil feeds are distinctly varied, but that high ash removal efficiencies are, nonetheless, obtainable under appropriate conditions for all three shale oils investigated. On the basis of the magnetic behavior exhibited by the shale oil solids, a qualitative

K. M. Jeong; L. Petrakis; M. Takayasu; F. J. Friedlaender

1984-01-01

119

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

Microsoft Academic Search

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

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

2007-01-01

120

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

DOEpatents

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

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

2010-02-09

121

Rare cell separation and analysis by magnetic sorting.  

PubMed

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

Zborowski, Maciej; Chalmers, Jeffrey J

2011-11-01

122

High-gradient compact linear accelerator  

DOEpatents

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

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

1998-01-01

123

High-gradient compact linear accelerator  

DOEpatents

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

Carder, B.M.

1998-05-26

124

Separation system and efficient capture of contaminants using magnetic nanoparticles  

US Patent & Trademark Office Database

Methods are disclosed for the capture, detection, separation, isolation and quantification of contaminants in a starting material. Also disclosed are competitive assay methods for the detection and quantification of contaminants in a starting material. Kits for use with the method are disclosed as well. A system for capturing, separating and/or concentrating contaminants from a material is also presented. The system captures, separates and/or concentrates contaminants such as bacteria, viruses, other microorganisms, and/or larger items, such as insects, from a variety of materials, such as food, and environmental and clinical materials. In general, the system uses a rotating magnetic field to mix the material with magnetic particles to capture the target contaminants, and a fixed magnetic field to separate and concentrate the captured target contaminants.

2010-04-20

125

Separating Magnetically Labeled and Unlabeled Biological Cells within Microfluidic Channels  

NASA Astrophysics Data System (ADS)

The transport of microscopic objects that rely on magnetic forces have numerous advantages including flexibility of controlling many design parameters and the long range magnetic interactions generally do not adversely affect biological or chemical interactions. We present results on the use of magnetic micro-arrays imprinted within polydimethylsiloxane (PDMS) microfluidic channels that benefit from these features and the ability to rapidly reprogram the magnetic energy landscape for cell manipulation and sorting applications. A central enabling feature is the very large, tunable, magnetic field gradients (> 10^4 T/m) that can be designed within the microfluidic architecture. Through use of antibody-conjugated magnetic microspheres to label biological cells, results on the transport and sorting of heterogeneous cell populations are presented. The effects of micro-array and fluid channel design parameters, competition between magnetic forces and hydrodynamic drag forces, and cell-labeling efficiency on cell separation are discussed.

Byvank, Tom; Vieira, Greg; Miller, Brandon; Yu, Bo; Chalmers, Jeffrey; Lee, L. James; Sooryakumar, R.

2011-03-01

126

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

PubMed

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

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

2009-12-01

127

Waste remediation using in situ magnetically assisted chemical separation  

SciTech Connect

The magnetically assisted chemical separation process (MACS) combines the selective and efficient separation afforded by chemical sorption with the magnetic recovery of ferromagnetic particles. This process is being developed for treating the underground storage tanks at Hanford. These waste streams contain cesium, strontium, and transuranics (TRU) that must be removed before this waste can be disposed of as grout. The separation process uses magnetic particles coated with either (1) a selective ion exchange material or an organic extractant containing solvent (for cesium and strontium removal) or (2) solvents for selective separation of TRU elements (e.g., TRUEX process). These coatings, by their chemical nature, selectively separate the contaminants onto the particles, which can then be recovered from the tank using a magnet. Once the particles are removed, the contaminants can either be left on the loaded particles and added to the glass feed slurry or stripped into a small volume of solution so that the extracting particles can be reused. The status of chemistry and separation process is discussed in this paper.

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

1993-11-01

128

Process to remove actinides from soil using magnetic separation  

DOEpatents

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

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

1996-01-01

129

Silica coated magnetic nanoparticles for separation of nuclear acidic waste  

NASA Astrophysics Data System (ADS)

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

Han, H.; Johnson, A.; Kaczor, J.; Kaur, M.; Paszczynski, A.; Qiang, Y.

2010-05-01

130

Development of chitosan-conjugated magnetite for magnetic cell separation  

Microsoft Academic Search

For the purpose of separating microorganisms from culture broth by magnetic force, magnetic particles were conjugated with a polymer to produce polymer-conjugated magnetite (polymer-mag). Among 4 preparation methods investigated—aminosilane coupling, glycidylsilane coupling, crosslinking, and co-precipitation—, polymer-mag prepared by co-precipitation showed the highest cell recovery and high dispersibility. When various cationic, anionic, and nonionic polymers were used to prepare polymer-mag and

Hiroyuki Honda; Atsushi Kawabe; Masashige Shinkai; Takeshi Kobayashi

1998-01-01

131

Advantage of combining magnetic cell separation with sperm preparation techniques  

Microsoft Academic Search

The selection of vital, non-apoptotic spermatozoa is a prerequisite for achieving optimal conception rates in assisted reproductive techniques. Magnetic cell sorting using annexin-V microbeads can effectively separate apoptotic and non-apoptotic spermatozoa. The objective of the present study was to optimize the integration of magnetic cell sorting in standard sperm preparations and to correlate the effect of different sperm preparation procedures

Tamer M Said; Sonja Grunewald; Uwe Paasch; Hans-Juergen Glander; Thomas Baumann; Christian Kriegel; Liang Li; Ashok Agarwal

2005-01-01

132

CHAOTIC MIXING OF MAGNETIC BEADS IN MICRO CELL SEPARATOR  

Microsoft Academic Search

ABSTRACT In micro-scale biological assay systems, the mixing of bio- molecules,becomes ,a critical ,issue because ,of their ,small diffusivity. Chaotic features in a novel micro-mixer designed for cell separation system based on magnetic beads (Suzuki and Ho, 2002) is investigated in detail by means of numerical simu- lation. The mechanism,and the optimum,condition to lead the motion of magnetic beads to

Hiroaki Suzuki; Nobuhide Kasagi; Chih-ming Ho

133

Separation of feeble magnetic particles with magneto-Archimedes levitation  

Microsoft Academic Search

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

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

2002-01-01

134

Magnetic Separation of Mineral Matter from Coal Liquids. Final Report.  

National Technical Information Service (NTIS)

The earlier study of the magnetic separation of mineral matter from coal liquids reported in EPRI Report AF-508 has been carried forward with significant improvements in the technique and results. Treatment of the dry residual filter-feed solids with appr...

E. Maxwell D. R. Kelland I. S. Jacobs L. M. Levinson

1978-01-01

135

Physicochemical properties of magnetically separated shale oil solids  

SciTech Connect

The authors present thermomagnetic and X-ray studies to show that the composition of shale oil solids magnetically separated from three different shale oil feeds are distinctly varied, but that high ash removal efficiencies are, nonetheless, obtainable under appropriate conditions for all three shale oils investigated. On the basis of the magnetic behavior exhibited by the shale oil solids, a qualitative measure of the different phase transformations and the species present is obtained. These data reflect the general occurrence of a paramagnetic phase mixed with a trace amount of a ferromagnetic component. This conclusion is consistent with the bulk mineralogy and elemental composition results for the shale magnetic separation system and the choice of operating parameters.

Jeong, K.M.; Petrakis, L.; Takayasu, M.; Friedlaender, F.J.

1984-01-01

136

Upgrading mixed polyolefin waste with magnetic density separation.  

PubMed

Polyolefin fractions are often end fractions resulting from the recycling of end-of-life consumer products. Polypropylene (PP) and polyethylene (PE) are present in such fractions as a mixture. For instance, the ratio of PP and PE in car scrap is 70:30 on average. However, the grade of the PP and PE should typically be better than 97% to be reused again as a high quality product. Density separation of the different polyolefins can be a solution. A promising separation technique is the inverse magnetic density separator (IMDS). This paper discusses the potential of shredder residue, one of the possible polyolefin's waste stream sources for the IMDS, in detail. Experiments with the separation of polyolefins with an IMDS prototype show both high grade and high recovery. The paper concludes with the economic opportunities of the IMDS in the recycling of polyolefins. PMID:19128952

Bakker, E J; Rem, P C; Fraunholcz, N

2009-05-01

137

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

PubMed

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

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

2014-06-01

138

A selection of high gradient cavity experiments  

SciTech Connect

In the two years since the 7th SRF workshop, a variety of cavity tests have been carried out with the objective to reproducibly achieve surface electric rf fields above 40 MV/m with no or only very little electron loading. This paper reports about a collection of tests on single cell and multi-cell cavities, which received standard surface treatments such as buffered chemical polishing and high pressure ultrapure water rinsing, but no heat treatments. Often the cavities were limited by quenches, posting a limit of 700 to 1,000 Oersted on achievable peak magnetic fields of high purity niobium RRR values between 200 and 250. In a seamless single cell cavity fabricated by V. Palmieri of INFN Legnaro by spinning, a very promising gradient of E{sub acc}=25 MV/m was measured. In collaboration with CERN, several tests on sputtering niobium prepared at CERN were also carried out, and accelerating gradients up to 25 MV/m were achieved. A single cell cavity, electron beam welded after electrochemical buffing, showed only good performance--E{sub p} > 50 MV/m--after the removal of more than 100 {micro}m of material. However, this cavity showed rather heavy Q disease even when cooled down rapidly; the Q degradation could be partially reversed by diffusing the oxygen from an anodized Nb{sub 2}O{sub 5} layer into the niobium by heating the cavity in-situ at T=250 C.

Peter Kneisel

1998-01-01

139

A separation property for magnetic Schrödinger operators on Riemannian manifolds  

NASA Astrophysics Data System (ADS)

We consider a Schrödinger differential expression L=?A+q on a complete Riemannian manifold (M,g) with metric g, where ?A is the magnetic Laplacian on M and q?0 is a locally square integrable function on M. In the terminology of W.N. Everitt and M. Giertz, the differential expression L is said to be separated in L2(M) if for all u?L2(M) such that Lu?L2(M), we have qu?L2(M). We give sufficient conditions for L to be separated in L2(M).

Milatovic, Ognjen

2011-01-01

140

Modeling Breakdown and Electron Orbits in High-Gradient Accelerating Cavities  

NASA Astrophysics Data System (ADS)

Next-generation rf accelerating cavities will employ very high-gradient electric fields, greater than 100 MV/m, as well as strong magnetic fields. However, breakdown of accelerating structures due to high field gradients is a major limitation on these accelerating cavities. One possible mechanism for breakdown initiation is the rapid buildup of electrons due to field emission coupled with secondary electron emission. Multipacting may enhance this effect. In order to understand the physical processes of breakdown initiation and the effectiveness of potential mitigation techniques, researchers in the Muon Accelerator Program are experimenting with a simplified cavity, referred to as the Box Cavity, in which they will measure breakdown under high-gradient rf with strong externally applied magnetic fields with different orientations. We present here simulation results for the box cavity including the effects of rf (805 MHz), magnetic fields, field-dependent emission, secondary electron emission, and space charge, using the 3-Dimensional plasma simulation code VORPAL. We measure the effect of different magnetic field strengths and orientations on electron orbits and buildup. We also simulate the effects of field emission in different parts of the box cavity, such as from corners of the box near the rf coupler, and measure the effects on electron buildup over many rf periods. These detailed and self-consistent models will aid experimentalists to understand breakdown onset in high-gradient metallic accelerating cavities.

Veitzer, Seth A.; Mahalingam, Sudhakar; Stoltz, Peter H.; Norem, J.

2010-11-01

141

Cell separation in a microfluidic channel using magnetic microspheres  

Microsoft Academic Search

Magnetophoretic isolation of biological cells in a microfluidic environment has strong relevance in biomedicine and biotechnology.\\u000a A numerical analysis of magnetophoretic cell separation using magnetic microspheres in a straight and a T-shaped microfluidic\\u000a channel under the influence of a line dipole is presented. The effect of coupled particle–fluid interactions on the fluid\\u000a flow and particle trajectories are investigated under different

Nipu Modak; Amitava Datta; Ranjan Ganguly

2009-01-01

142

Radiolysis and hydrolysis of magnetically assisted chemical separation particles  

SciTech Connect

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

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

1995-05-01

143

Radiolysis and hydrolysis of magnetically assisted chemical separation particles  

SciTech Connect

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

Buchholz, B.A.; Nunez, L.; Vandegrift, G.F. [Argonne National Lab., IL (United States)

1996-08-01

144

A microfabricated planar magnetic particle separator with optically inspectable flow channel  

Microsoft Academic Search

A new planar magnetic particle separator with opening flow channel which can separate magnetic beads from suspended bio-fluids has been realized on silicon and Pyrex glass wafers, using microfabrication techniques. Electromagnets and fluid channels are separately fabricated, and then two components are bonded together to construct the separator using electrostatic wafer bonding techniques. Separation tests are performed by flowing a

Wenjin Zhang; C. H. Ahn

1996-01-01

145

SLIM, Short-pulse Technology for High Gradient Induction Accelerators  

SciTech Connect

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

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

2008-12-16

146

High and Ulta-High Gradient Quadrupole Magnets.  

National Technical Information Service (NTIS)

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours a...

W. O. Brunk D. R. Walz

1985-01-01

147

The Yale Gas-Filled Split Pole Magnetic Separator  

NASA Astrophysics Data System (ADS)

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

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

1998-10-01

148

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

149

Rapid microfluidic separation of magnetic beads through dielectrophoresis and magnetophoresis.  

PubMed

We present the design and fabrication of a new microfluidic device in which the dielectrophoresis and magnetophoresis phenomena were used for the separation of the superparamagnetic microbeads of different sizes. By exploiting the fact that two different particles can exhibit different dielectrophoretic force-frequency spectra, we utilize this device to perform multiplex detection from a single sample solution. We found the transition frequency range for 1, 2.8, and 4.5 microm magnetic beads using our device. Bead-based analysis revealed that a high separation efficiency ( approximately 90%) could be obtained from a single sample solution containing both 4.5 and 2.8 microm beads. The average flow velocity of the beads was maintained at 9.8 mm/s, enabling fast analysis with a smaller amount of reagents. The magnetic field distribution on the beads and the bead flow at the channel cross section for different dielectrophoretic conditions was obtained using CFD-ACE(+) simulation. Issues relating to the fabrication and operation of the device are discussed in detail. Finally, we demonstrated the feasibility of parallel detection/trapping of different beads on the same chip. This separation approach offers the performance of multiplex analysis in lab-on-a-chip devices. PMID:19425001

Krishnan, Jegatha Nambi; Kim, Choong; Park, Hyun Jik; Kang, Ji Yoon; Kim, Tae Song; Kim, Sang Kyung

2009-05-01

150

Experimental and theoretical investigation of high gradient acceleration  

SciTech Connect

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

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

1992-02-01

151

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

Microsoft Academic Search

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 6T. The magnetic field distribution

T. Oka; H. Seki; T. Kimura; D. Mimura; S. Fukui; J. Ogawa; T. Sato; M. Ooizumi; H. Fujishiro; H. Hayashi; K. Yokoyama; C. Stiehler

2011-01-01

152

Apparatus for magnetic separation of paramagnetic and diamagnetic material  

US Patent & Trademark Office Database

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

1988-10-18

153

Apparatus for magnetic separation of paramagnetic and diamagnetic material  

DOEpatents

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

Doctor, Richard D. (Glen Ellyn, IL)

1988-01-01

154

Correlation of physical coal separations: Part I  

Microsoft Academic Search

Experimental separations of the inorganic material from a coal by the specific-gravity (wet), high-gradient magnetic (dry), and open-gradient magnetic (dry) processes were performed and analyzed to compare for Btu recovery vs efficiency of removal of pyrite and ash and to determine the degree of liberation of the inorganics by the crushing. It is shown that the liberated minerals can be

Hise

1979-01-01

155

Summary Report of Working Group 2: High-Gradient Structures  

SciTech Connect

We give a summary of the presentations and discussions that took place in the High Gradient Structures Working Group at the 2006 Advanced Accelerator Concepts Workshop. Following the working group mission statement and charge, the talks are listed, with brief descriptions and highlights of the discussions that they generated.

Tantawi, Sami G.; Dolgashev, Valery A. [Stanford Linear Accelerator Center, Menlo Park, CA 94025 (United States)

2006-11-27

156

High gradient acceleration in a 17 GHz photocathode RF gun  

Microsoft Academic Search

The physics and technological issues involved in high gradient particle acceleration at high microwave (RF) frequencies are under study at MIT. The 17 GHz photocathode RF gun has a 1½ cell room temperature copper cavity with a peak accelerating gradient of about 250 MV\\/m. The anticipated beam parameters, when operating with a photoemission cathode, are: energy 2 MeV, normalized emittance

S. C. Chen; J. Gonichon; L. C.-L. Lin; R. J. Temkin; S. Trotz; B. G. Danly; J. S. Wurtele

1993-01-01

157

On-chip Magnetic Separation and Cell Encapsulation in Droplets  

NASA Astrophysics Data System (ADS)

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

158

Experimental and theoretical investigation of high gradient acceleration  

SciTech Connect

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

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

1993-01-01

159

Ion Bombardment of Microprotrusions in High Gradient Accelerating Structures  

SciTech Connect

This paper starts from a brief overview of theoretical studies of high-gradient accelerating structures at the University of Maryland. The rest of the paper is devoted to the analysis of ion bombardment of small protrusions in such structures. First, this problem is studied analytically. Then, some results of particle-in-cell simulations performed with the use of code WARP are presented and discussed.

Nusinovich, Gregory S.; Kashyn, Dmytro; Antonsen, Thomas Jr.; Haber, Irving [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742-3511 (United States)

2010-11-04

160

High gradient cavity beat - wave accelerator at W band  

Microsoft Academic Search

Pulsed rf heating is a fundamental limit on high-gradient acceleration in copper structures. Reduction of pulsed heating is favored by a short exposure time for the copper; yet in conventional accelerators, efficiency requires an exposure time of order a cavity fill time. At W-Band, the cavity beat-wave transformer concept permits efficient energy transfer to resonant accelerating modes on a sub-nanosecond

David H. Whittum; Ping J. Chou; Heino Henke

1998-01-01

161

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

NASA Astrophysics Data System (ADS)

Magnetically separable composite photocatalysts, TiO 2 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%.

Wang, Shaohua; Zhou, Shaoqi

2010-08-01

162

ACSD labelling and magnetic cell separation: a rapid method of separating antibody secreting cells from non-secreting cells  

Microsoft Academic Search

Several new ways of selecting cells have recently been developed. These include magnetic separation of cells by labelling with magnetic beads against the recombinant product, gel microdrop technology which encapsulates the cells in gelatine beads and matrix-based secretion assays. Affinity capture surface display (ACSD) is a matrix-based assay for the enrichment of high producing cells and relies on the strong

Silvia Carroll; Mohamed Al-Rubeai

2005-01-01

163

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

NASA Astrophysics Data System (ADS)

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

Okamoto, T.; Tachibana, S.; Miura, O.; Takeuchi, M.

2011-11-01

164

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

DOEpatents

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

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

1980-11-06

165

Continuous separation of non-magnetic particles through negative magnetophoresis inside ferrofluids  

Microsoft Academic Search

We present a simple, low-cost, effective, and label-free continuous flow non-magnetic microparticle separation scheme in a microfluidic device under static magnetic fields. The separation process is based on negative magnetophoresis and uses water-based ferrofluids. We exploit the difference in particle sizes to achieve continuous binary separation of fluorescent microparticles with high throughput and efficiency. We demonstrate size-based separation (2.1 ?m

Taotao Zhu; Francisco Marrero; Leidong Mao

2010-01-01

166

Enhanced separation of magnetic and diamagnetic particles in a dilute ferrofluid  

NASA Astrophysics Data System (ADS)

Traditional magnetic field-induced particle separations take place in water-based diamagnetic solutions, where magnetic particles are captured while diamagnetic particles flow through without being affected by the magnetic field. We demonstrate that replacing the diamagnetic aqueous medium with a dilute ferrofluid can significantly increase the throughput of magnetic and diamagnetic particle separation. This enhancement is attributed to the simultaneous positive and negative magnetophoresis of magnetic and diamagnetic particles, respectively, in a ferrofluid. The particle transport behaviors in both ferrofluid- and water-based separations are predicted using an analytical model.

Liang, Litao; Zhang, Cheng; Xuan, Xiangchun

2013-06-01

167

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

PubMed Central

Particle separation is important to many chemical and biomedical applications. Magnetic field-induced particle separation is simple, cheap, and free of fluid heating issues that accompany electric, acoustic, and optical methods. We develop herein a novel microfluidic approach to continuous sheath-free magnetic separation of particles. This approach exploits the negative or positive magnetophoretic deflection to focus and separate particles in the two branches of a U-shaped microchannel, respectively. It is applicable to both magnetic and diamagnetic particle separations, and is demonstrated through the sorting of 5??m and 15??m polystyrene particles suspended in a dilute ferrofluid.

Liang, Litao; Xuan, Xiangchun

2012-01-01

168

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

PubMed

Particle separation is important to many chemical and biomedical applications. Magnetic field-induced particle separation is simple, cheap, and free of fluid heating issues that accompany electric, acoustic, and optical methods. We develop herein a novel microfluidic approach to continuous sheath-free magnetic separation of particles. This approach exploits the negative or positive magnetophoretic deflection to focus and separate particles in the two branches of a U-shaped microchannel, respectively. It is applicable to both magnetic and diamagnetic particle separations, and is demonstrated through the sorting of 5??m and 15??m polystyrene particles suspended in a dilute ferrofluid. PMID:24175006

Liang, Litao; Xuan, Xiangchun

2012-01-01

169

Factors limiting the operation of structures under high gradient  

SciTech Connect

Factors limiting the operation of rf structures under high-gradient conditions are described. Included are recent rf measurements at laboratories in Europe, Asia, and North America and how these measurements relate to earlier data as exemplified by the use of the Kilpatrick criterion (Kp). Operation limitations will cover mechanical, geometry, thermal, and surface constraints and the associated impact on structure design, fabrication, and material selection. Generally, structures operating continuous wave (100% duty factor) appear to be limited to peak surface fields at about twice the Kilpatrick limit, whereas pulsed structures operating with pulse lengths less than a millisecond can attain peak surface fields five times the Kilpatrick limit.

Schriber, S.O.

1986-01-01

170

An integrated microfluidic platform for magnetic microbeads separation and confinement  

Microsoft Academic Search

An innovative microfluidic platform for magnetic beads manipulation is introduced, consisting of novel microfabricated 3D magnetic devices positioned in a microfluidic chamber. Each magnetic device comprises of an embedded actuation micro-coil in various design versions, a ferromagnetic pillar, a magnetic backside plate and a sensing micro-coil. The various designs of the micro-coils enable efficient magnetic beads trapping and concentration in

Qasem Ramadan; Victor Samper; Daniel P. Poenar; Chen Yu

2006-01-01

171

On-chip free-flow magnetophoresis: continuous flow separation of magnetic particles and agglomerates.  

PubMed

The separation of magnetic microparticles 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. Magnetic particles could thus be separated from each other and from nonmagnetic materials. Magnetic and nonmagnetic particles were introduced into a microfluidic separation chamber, and their deflection was studied under the microscope. The magnetic particles were 2.0 and 4.5 microm in diameter with magnetic susceptibilities of 1.12 x 10(-4) and 1.6 x 10(-4) m(3) kg(-1), respectively. The 4.5-microm particles with the larger susceptibility were deflected further from the direction of laminar flow than the 2.0-microm magnetic particles. Nonmagnetic 6-microm polystyrene beads, however, were not deflected at all. Furthermore, agglomerates of magnetic particles were found to be deflected to a larger extent than single magnetic particles. The applied flow rate and the strength and gradient of the applied magnetic field were the key parameters in controlling the deflection. This separation method has a wide applicability since magnetic particles are commonly used in bioanalysis as a solid support material for antigens, antibodies, DNA, and even cells. Free-flow magnetophoretic separations could be hyphenated with other microfluidic devices for reaction and analysis steps to form a micro total analysis system. PMID:15595866

Pamme, Nicole; Manz, Andreas

2004-12-15

172

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

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

Thompson, M. C. [Lawrence Livermore National Laboratory, Livermore, California, 90095 (United States); Badakov, H.; Rosenzweig, J. B.; Travis, G. [UCLA Department of Physics and Astronomy, Los Angeles, California, 90095 (United States); Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D. [Stanford Linear Accelerator Center, Stanford, California, 94309 (United States); Muggli, P. [University of Southern California Los Angeles, California, 90089 (United States); Scott, A. [UCSB Department of Physics, Santa Barbara, California, 93106 (United States); Yoder, R. [Manhattan College, Riverdale, New York, 10471 (United States)

2006-11-27

173

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

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

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

2006-08-04

174

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect

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

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

2007-03-27

175

Magnetic Microspheres Prepared by Redox Polymerization Used in a Cell Separation Based on Gangliosides  

Microsoft Academic Search

A facile method is described for making magnetic microspheres that bind specifically to cell surfaces, in order to separate cells magnetophoretically. Control over the sizes of the spheres is effected by using their magnetic cores as part of a redox polymerization system. The use of the microspheres is demonstrated with a separation involving C-1300 neuroblastoma cells, 10 percent of which

Paul L. Kronick; Graham Lem. Campbell; Kenneth Joseph

1978-01-01

176

Glassy magnetic behavior in the phase-separated perovskite cobaltites  

Microsoft Academic Search

In this paper we demonstrate that the origin of the glassy behaviors (memory, aging, etc.) in the phase-separated perovskite cobaltites cannot be simply ascribed to intercluster interactions as the phase-separated manganites can. Instead, our study indicates that both the intercluster interactions and a spin glasslike phase contribute to the glassy behaviors. Thus, this study distinguishes the picture of phase separation

Yan-Kun Tang; Young Sun; Zhao-Hua Cheng

2006-01-01

177

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

Microsoft Academic Search

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

M. D. KAMINSKI; L. NUÑEZ

2000-01-01

178

Continuous magnetophoretic separation of blood cells in microdevice format  

NASA Astrophysics Data System (ADS)

This paper presents a method for continuous magnetophoretic separation of red and white blood cells from whole blood based on their native magnetic properties. The microsystem separates the blood cells using a high gradient magnetic separation method without the use of additives such as magnetic tagging or inducing agents. A theoretical model of the magnetophoretic microseparator is derived and verified by comparison with finite element simulation. The microseparator is fabricated using microfabrication technology, enabling the integration of microscale magnetic flux concentrators in an aqueous microenvironment, providing strong magnetic forces, and fast separations. Experimental tests are performed using a permanent magnet to create an external magnetic flux of 0.2 T, and measuring the movement of red blood cells within the microchannel of the microseparator. The experimental results correlate well with the theoretical results.

Han, Ki-Ho; Bruno Frazier, A.

2004-11-01

179

Modified Magnicon for High-Gradient Accelerator R&D  

SciTech Connect

Analysis, and low-power cold tests are described on a modified design intended for the Ka-band pulsed magnicon now in use for high-gradient accelerator R and D and rare elementary particle searches at the Yale University Beam Physics Laboratory. The modification is mainly to the output cavity of the magnicon, which presently operates in the TM310 mode. It is proposed to substitute for this a dual-chamber TE311 cavity structure. The first chamber is to extract about 40% of the beam power (about 25 MW) at 34.272 GHz, while the second chamber is to convey the power to four WR-28 output waveguides. Minor design changes are also proposed for the penultimate 11.424 GHz cavity and the beam collector. The intention of these design changes is to allow the magnicon to operate reliably 24/7, with minor sensitivity to operating parameters.

Jay L. Hirshfield

2011-12-19

180

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

181

High-yield cell separations using magnetic nanowires  

Microsoft Academic Search

Ferromagnetic nanowires are demonstrated as a new tool in performing high-yield, single step cell separations on cultures of mammalian cells. The nanowires are made by electrochemical deposition in nanoporous templates, and when added to cultures of 3T3 mouse fibroblast cells, the nanowires can readily bind to the cells. The effectiveness in cell separations of Ni nanowires 350 nm in diameter

Anne Hultgren; Monica Tanase; Christopher S. Chen; Daniel H. Reich

2004-01-01

182

Magnetic and fluorescence-encoded polystyrene microparticles for cell separation  

Microsoft Academic Search

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 mum polystyrene microparticles for separation of particle-bound cells from non-bound cells in suspension by means of a

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

2008-01-01

183

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

PubMed

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

184

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

PubMed

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

Moon, Hyung-Mo; Kim, Jin-Woo

2010-01-01

185

High resolution separations of nanoparticles with improved electrical and magnetic field flow fractionation  

NASA Astrophysics Data System (ADS)

Electrical and Magnetic Field Flow Fractionation (ElFFF, MFFF) methods are two rapidly developing separation and characterization techniques using electrical and magnetic fields that have not been regularly applied to nanoparticle fractionation, separation, and characterization. Currently, several limitations characteristic of both techniques prevent them from being widely used tools in the separation of nanoparticles. In this work, we address the main limitations of both techniques and develop methods to enhance their separation abilities, and particularly their application to nanoparticles. Specifically, one order of magnitude improvement is obtained in the separation capability of the Cyclical ElFFF systems. It is shown that high resolution separations of 15 and 40 nm gold nanoparticles can be achieved by Cyclical ElFFF, for which the separation of particles smaller than 100 nanometers was not demonstrated before. In addition, the first particle based modeling of Electrical Field Flow Fractionation (ElFFF) systems is demonstrated for the first time. The developed particle based simulation code allows visualization of individual particles inside the separation channel, which leads to a better understanding of ElFFF operation and mechanisms. The outputs of the simulation code show good agreement with the experimental results. We have also fabricated a new ElFFF system and tested it with four different channel heights to investigate the effect of channel height on the separation performance of the ElFFF systems. It is also shown for the first time that ElFFF can be used for the separation of magnetic nanoparticles. In previously reported studies, magnetic field driven techniques were used for the separation of magnetic particles. However, in this study, it is revealed that an electrical field driven technique can also be used for the separation of these nanoparticles. A new magnetic field flow fractionation (MFFF) system was designed and modeled using both finite element and particle based simulations. As a change from current magnetic FFF systems, which use static magnetic fields, the new system uses cyclical magnetic fields for the separation of the particles. Finally, a novel passive magnetic microfluidic mixer is designed and fabricated which produces high efficiency mixing at the microscale, without need of an active actuation mechanism.

Tasci, Tonguc Onur

186

Development of dielectric-based high gradient accelerating structures.  

SciTech Connect

High gradient accelerating structures using dielectric-lined circular waveguides have been developed for a number of years at Argonne National Laboratory. In this article, we first report the experimental results of high power rf testing on the quartz based Dielectric-Loaded Accelerating (DLA) structure carried out on Feb. 2006 at the Naval Research Laboratory. The motivation for this experiment is to test the multipactor effect on different materials under high power and high vacuum condition. Up to 12 MW pulsed rf went through the tube without breakdown. Multipactor appeared during the experiment but with different features compared to other materials like alumina. Photomultiplier Tube (PMT) measurements were introduced into the experiment for the first time to observe the light emission time and intensity. In the second part of this paper, ways to achieve higher gradient for DLA structures are proposed: (1) smaller ID and longitudinal gap free DLA structures to reduce multipactor and obtain higher gradient; (2) new coaxial type coupler to avoid dielectric gap and improve impedance matching; (3) double layered DLA structure to reduce rf loss and enhance shunt impedance as well.

Jing, C.; Gai, W.; Konecny, R.; Power, J.; Liu, w.; Gold, S. H.; Kinkead, A. K.; Kanareykin, A.; Kazakov, S.; High Energy Physics; Euclid Techlabs, LLC; Naval Research Lab.; LET Corp.; KEK

2006-01-01

187

Development of Dielectric-Based High Gradient Accelerating Structures  

SciTech Connect

High gradient accelerating structures using dielectric-lined circular waveguides have been developed for a number of years at Argonne National Laboratory. In this article, we first report the experimental results of high power rf testing on the quartz based Dielectric-Loaded Accelerating (DLA) structure carried out on Feb. 2006 at the Naval Research Laboratory. The motivation for this experiment is to test the multipactor effect on different materials under high power and high vacuum condition. Up to 12 MW pulsed rf went through the tube without breakdown. Multipactor appeared during the experiment but with different features compared to other materials like alumina. Photomultiplier Tube (PMT) measurements were introduced into the experiment for the first time to observe the light emission time and intensity. In the second part of this paper, ways to achieve higher gradient for DLA structures are proposed: 1) smaller ID and longitudinal gap free DLA structures to reduce multipactor and obtain higher gradient; 2) new coaxial type coupler to avoid dielectric gap and improve impedance matching; 3) double layered DLA structure to reduce rf loss and enhance shunt impedance as well.

Jing, C. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH-44139 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States); Gai, W.; Konecny, R.; Power, J.; Liu, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States); Gold, S. H. [Plasma Physics Division, Naval Research Laboratory, Washington DC, 20375 (United States); Kinkead, A. K. [LET Corp., Washington DC, 20007 (United States); Kanareykin, A. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH-44139 (United States); Kazakov, S. [KEK, Tsukuba (Japan)

2006-11-27

188

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

SciTech Connect

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

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

2010-09-09

189

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

National Technical Information Service (NTIS)

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

C. Hoffmann K. Keller

2005-01-01

190

Combined Centrifugal Separation-Flotation-Magnetic Concentration Flowsheet for Treatment of Wolframite Slimes.  

National Technical Information Service (NTIS)

Based on testwork and plant practice a flowsheet has been developed combining centrifugal separation with flotation and magnetic concentration for the treatment of wolframite slimes to yield a high-grade tungsten concentrate. In May, 1977, laboratory and ...

P. Liu D. Wang

1987-01-01

191

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

EPA Science Inventory

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

192

A Novel Blind Separation Method in Magnetic Resonance Images  

PubMed Central

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

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

2014-01-01

193

A new high-gradient correction quadrupole for the Fermilab luminosity upgrade  

SciTech Connect

Special superconducting correction quadrupoles are needed for the luminosity upgrade of the Fermilab Tevatron Collider. These correctors are part of the low-beta system for the interaction regions at B/phi/ and D/phi/. The requirements are high gradient and low current. A quadrupole has been designed that meets the operating gradient of 0.63 T/cm at 1086 A. The one-layer quadrupole is wound with a cable consisting of five individually insulated rectangular strands. The five strands are overwrapped with Kapton and epoxy impregnated glass tape. The winding, curing and collaring of the magnet is accomplished in the same manner as Tevatron-like magnets using Rutherford style cable. Once the magnet is complete the five strands are connected in series. A prototype quadrupole has been assembled and tested. The magnet reached a plateau current of 1560 A corresponding to a gradient of 0.91 T/cm without training. The measured field harmonics are substantially better than required. 8 refs., 6 figs., 4 tabs.

Mantsch, P.; Carson, J.; Riddiford, A.; Lamm, M.J.

1989-03-01

194

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

NASA Astrophysics Data System (ADS)

The ESR measurements of the EuB6 single crystal samples were executed on frequency 9.25 GHz in TE102 rectangular cavity in the temperature range from 15 to 300 K. We used samples of identical form and size, but different crystallografic orientation to estimate their magnetization. At T = 30 - 40K was observed the magnetic phase separation, which, most likely, is accompanied also by charging separation. The anisotropy magnetization of more intensive magnetic phase (with anti-Kondo interaction) along the different crystallographic directions was found above a temperature of the ferromagnetic transition. We conclude that this result connect with existence the ferronic states and charging separation in the EuB6 single crystal. Estimations of angular distribution of the magnetic moment of ferrons in EuB6 are made.

Altshuler, T. S.; Goryunov, Yu V.; Shitsevalova, N. Yu; Dukhnenko, A.

2010-01-01

195

Separation of binary granular mixtures under vibration and differential magnetic levitation force.  

PubMed

The application of both a strong magnetic field and a magnetic field gradient to a diamagnetic or paramagnetic material can produce a vertical force that acts in concert with the force of gravity. We consider a binary granular mixture in which the two components have different magnetic susceptibilities and therefore experience different effective forces of gravity when subjected to an inhomogeneous magnetic field. Under vertical vibration, such a mixture may rapidly separate into regions almost pure in the two components. We investigate the conditions for this behavior, studying the speed and completeness of separation as a function of differential effective gravity and the frequency and amplitude of vibration. The influence of the cohesive magnetic dipole-dipole interactions on the separation process is also investigated. In our studies insight is gained through the use of a molecular dynamics simulation model. PMID:15783320

Catherall, A T; López-Alcaraz, P; Sánchez, P; Swift, Michael R; King, P J

2005-02-01

196

Magnetic phase separation in europium hexaboride and its relation to the Kondo interaction  

NASA Astrophysics Data System (ADS)

Europium hexaboride single crystals have been investigated using the electron paramagnetic resonance at a frequency of 9.25 GHz in the temperature range 10 300 K. The magnetic phase separation of the spin system of europium ions Eu2+ is observed. The cause of the separation is the formation of the polarons of two types associated with the Kondo and anti-Kondo couplings of charge carriers of the valence and conduction bands, respectively, with the localized magnetic moments of Eu2+.

Al'Tshuler, T. S.; Goryunov, Yu. V.; Dukhnenko, A. V.; Shitsevalova, N. Yu.

2008-10-01

197

Magnetic microheaters for cell separation, manipulation, and lysing  

Microsoft Academic Search

Precise heating is important for biological culturing, biological characterization, and thermal lysis, while cellular manipulation has been an area of significant interest and has been explored by a variety of methods. In this work, we present a preliminary study of the use of metallic thermal probes. The probes were used for magnetophoresis and micromanipulation of magnetically labeled HeLa cells. The

Angelo Gaitas; Paddy French

2011-01-01

198

Shock and Current-Sheet Separation in Magnetic Shock Tubes  

Microsoft Academic Search

The problem of separation of a shock wave from the current driving it, is experimentally investigated over a wide range of Mach numbers in a single gas. In order to do this, a parallel plate shock tube was developed which produces repeatable shocks in hydrogen from Mach 20-180 at initial pressures from 75-460 ?Hg. In the present work, no preheating

F. Y. Sorrell

1969-01-01

199

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

PubMed

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups. PMID:22767355

Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

2013-01-01

200

Separation of Uranium by an Extractant Encapsulated Magnetic Alginate Gels  

NASA Astrophysics Data System (ADS)

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.

201

Structure and photocatalytic performance of magnetically separable titania photocatalysts for the degradation of propachlor  

Microsoft Academic Search

A magnetic photocatalyst was prepared by modification of TiO2 nanoparticles (Degussa P25) with nanocrystalline ?-Fe2O3 nanoparticles through a protective lining made up of two oppositely charged polyelectrolytes. As-prepared magnetically separable photocatalysts differing in ?-Fe2O3 loading (3, 8, 13, 20 and 30wt.%) were characterized by XRD, TEM, thermal analysis, Mössbauer and magnetic measurements. The photocatalytic efficiency of the nanocomposite catalysts was

V. Belessi; D. Lambropoulou; I. Konstantinou; R. Zboril; J. Tucek; D. Jancik; T. Albanis; D. Petridis

2009-01-01

202

A novel blind separation method in magnetic resonance images.  

PubMed

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

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

2014-01-01

203

An on-chip magnetic bead separator using spiral electromagnets with semi-encapsulated permalloy  

Microsoft Academic Search

A new planar bio-magnetic bead separator on a glass chip has been designed, fabricated and tested. The separator is composed of micromachined semi-encapsulated spiral electromagnets and fluid channels, which have been separately fabricated and then bonded. The device was tested with super-paramagnetic beads of mean diameter 1 ?m which were suspended in a buffered solution. When a DC current of

Jin-Woo Choi; Trifon M. Liakopoulos; Chong H. Ahn

2001-01-01

204

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

PubMed Central

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

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

2010-01-01

205

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

NASA Astrophysics Data System (ADS)

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

206

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

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

207

Selective loss of progenitor subsets following clinical CD34+ cell enrichment by magnetic field, magnetic beads or chromatography separation  

Microsoft Academic Search

In this preclinical evaluation we have compared the efficacy of three clinical CD34+enrichment procedures with respect to purity, yield and recovery, as well as risk of selective loss of CD34+ lineage-specific subsets. The three devices work by different principles and have several different manipulation steps: The magnetic field separator uses paramagnetic iron-dextran particles; the magnetic microbead selection is based on

HE Johnsen; M Hutchings; E Taaning; T Rasmussen; LM Knudsen; SW Hansen; H Andersen; E Gaarsdal; L Jensen; K Nikolajsen; E Kjæsgård; NE Hansen

1999-01-01

208

Direct observation of magnetically induced phase separation in Co-W sputtered thin films  

NASA Astrophysics Data System (ADS)

Phase separation of Co-W sputtered thin films having a large magnetocrystalline anisotropy energy have been investigated. A nanoscale compositional fluctuation caused by magnetically induced phase separation was directly confirmed in the films deposited on a heated substrate in analogy with Co-Cr-based alloys. The difference between the phase separation features in Co-W and Co-Cr is attributed to the difference in their elastic energy. It is expected that the phase separation is enhanced by selecting optimum sputtering conditions. The Co-W system, therefore, is considered to be a promising candidate as a base alloy system for high-density recording media.

Oikawa, K.; Qin, G. W.; Sato, M.; Okamoto, S.; Kitakami, O.; Shimada, Y.; Fukamichi, K.; Ishida, K.; Koyama, T.

2004-09-01

209

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

PubMed

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

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

2014-07-01

210

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

SciTech Connect

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

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

1995-05-01

211

The XFEM for high-gradient solutions in convection-dominated problems  

Microsoft Academic Search

SUMMARY Convection-dominated problems typically involve solutions with high gradients near the domain boundaries (boundary layers) or inside the domain (shocks). The approximation of such solutions by means of the standard finite element method requires stabilization in order to avoid spurious oscillations. However, accurate results may still require a mesh refinement near the high gradients. Herein, we investigate the extended finite

Safdar Abbas; Alaskar Alizada; Thomas-Peter Fries

2009-01-01

212

Proton-nuclear magnetic resonance study of water solvent magnetic fluid's phase separation  

Microsoft Academic Search

We report proton-nuclear magnetic resonance experiments on a diluted water solvent magnetic fluid of colloidal volume fraction phi=0.30%. By sweeping the external magnetic field strength, H0, applied to the magnetic fluid around 4000 Oe, we found one major resonant field, HM, and two satellite resonant fields, HS1 and HS2, which correspond to resonant protons in three different coexisting phases. HS1

Susamu Taketomi; Shin-Hachiro Saito

2000-01-01

213

Botryococcus braunii cells: Ultrasound-intensified outdoor cultivation integrated with in situ magnetic separation.  

PubMed

An integrated system combining ultrasound-intensified outdoor cultivation of Botryococcus braunii with in situ magnetic harvesting of the algal cells was developed. The algal cells were cultivated in 200L plastic bag reactors, and seven five-minute ultrasonic treatments at a four-day interval using a fixed frequency of 40kHz and a total power of 300W improved algal cell biomass and hydrocarbon productivity. The algal cells were harvested using functional magnetic particles and a magnetic separator, and a recovery efficiency of 90% was obtained under continuous operation at a flow rate of 100mL/min using the in situ magnetic separation system. The overall production cost using the integrated system was US$ 25.14 per kilogram of B. braunii dry biomass. The system developed in this study provides a base for the industrial production of B. braunii. PMID:24998478

Wang, Shi-Kai; Wang, Feng; Stiles, Amanda R; Guo, Chen; Liu, Chun-Zhao

2014-09-01

214

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

PubMed

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

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

2013-11-21

215

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

Microsoft Academic Search

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

Elmars Blums; Ansis Mezulis; Michail Maiorov; Gunars Kronkalns

1997-01-01

216

Protein-stabilized magnetic fluids  

Microsoft Academic Search

The adsorption of bovine serum albumin (BSA) and egg yolk phosvitin on magnetic fluid particles was investigated. Incubation mixtures were prepared by mixing an alkaline suspension of tetramethylammonium-coated magnetite cores with protein solutions at various protein\\/Fe3O4 ratios, followed by dialysis against a 5 mM TES buffer (pH 7.0), after which separation of bound and non-bound protein by high-gradient magnetophoresis was

S. J. H. Soenen; M. Hodenius; T. Schmitz-Rode; M. de Cuyper

2008-01-01

217

Protein-stabilized magnetic fluids  

Microsoft Academic Search

The adsorption of bovine serum albumin (BSA) and egg yolk phosvitin on magnetic fluid particles was investigated. Incubation mixtures were prepared by mixing an alkaline suspension of tetramethylammonium-coated magnetite cores with protein solutions at various protein\\/Fe3O4 ratios, followed by dialysis against a 5mM TES buffer (pH 7.0), after which separation of bound and non-bound protein by high-gradient magnetophoresis was executed.

S. J. H. Soenen; M. Hodenius; T. Schmitz-Rode; M. De Cuyper

2008-01-01

218

New High Performance Magnet Structures for Bead Based MolecularSeparation  

SciTech Connect

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

Humphries, David

2005-06-01

219

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

220

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

PubMed

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

221

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

PubMed

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

2014-06-17

222

Sustained Magnetic Fields Reveal Separate Sites for Sound Level and Temporal Regularity in Human Auditory Cortex  

Microsoft Academic Search

Magnetoencephalographywas used to investigate the relationship between the sustained magnetic field in auditory cortex and the perception of periodic sounds. The response to regular and irregular click trains was measured at three sound intensities. Two separate sources were isolated adjacent to primary auditory cortex: One, located in lateral Heschl's gyrus, was particularly sensitive to regularity and largely insensitive to sound

Alexander Gutschalk; Roy D. Patterson; André Rupp; Stefan Uppenkamp; Michael Scherg

2002-01-01

223

Separable constrained nonlinear least squares and an application in magnetic resonance spectroscopy  

Microsoft Academic Search

An application in magnetic resonance spectroscopy (MRS) quantification models a signal as a linear combination of nonlinear functions. It leads to a separable nonlinear least squares fitting problem, with linear bound constraints on some variables. The Variable Projection (VARPRO) (1) technique can be applied to this problem, but needs to be adapted in several respects. If only the nonlinear variables

Diana M. Sima

224

A method to obtain uniform magnetic-field energy density gradient distribution using discrete pole pieces for a microelectromechanical-system-based magnetic cell separator  

Microsoft Academic Search

A spatially uniform magnetic energy density gradient (?B2) distribution offers a controlled environment to separate magnetically tagged cells or biomolecules based on their magnetophoretic mobility [L. R. Moore et al., J. Biochem. Biophys. Methods 37, 11 (1998)]. A design to obtain a uniform ?B2 distribution for a microelectromechanical-systems-based magnetic cell separator was developed. The design consists of an external magnetic

Pulak Nath; Lee R. Moore; Maciej Zborowski; Shuvo Roy; Aaron Fleischman

2006-01-01

225

High efficiency protein separation with organosilane assembled silica coated magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2008-10-01

226

Improvement of Immunomagnetic Separation for Escherichia coli O157:H7 Detection by the PickPen Magnetic Particle Separation Device  

Microsoft Academic Search

Conventional immunomagnetic separation (IMS) procedures, which use an external magnetic source to capture magnetic particles against the side of a test tube, are labor-intensive and can have poor sensitivity for the target organism because of high background microflora that is not effectively washed away during the IMS process. This report compares the conventional IMS procedure to a new IMS procedure

XIANGWU NOU; TERRANCE M. ARTHUR; JOSEPH M. BOSILEVAC; DAYNA M. BRICHTA-HARHAY; MICHAEL N. GUERINI; NORASAK KALCHAYANAND; MOHAMMAD KOOHMARAIE

2006-01-01

227

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

NASA Astrophysics Data System (ADS)

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 1.1×10 -4 and 1.6×10 -4 m 3 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.

Pamme, Nicole; Eijkel, Jan C. T.; Manz, Andreas

2006-12-01

228

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

PubMed

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

Giakisikli, Georgia; Anthemidis, Aristidis N

2013-07-30

229

Isolation of osteoprogenitors from human jaw periosteal cells: a comparison of two magnetic separation methods.  

PubMed

Human jaw periosteum tissue contains osteoprogenitors that have potential for tissue engineering applications in oral and maxillofacial surgeries. To isolate osteoprogenitor cells from heterogeneous cell populations, we used the specific mesenchymal stem cell antigen-1 (MSCA-1) antibody and compared two magnetic separation methods. We analyzed the obtained MSCA-1(+) and MSCA-1(-) fractions in terms of purity, yield of positive/negative cells and proliferative and mineralization potentials. The analysis of cell viability after separation revealed that the EasySep method yielded higher viability rates, whereas the flow cytometry results showed a higher purity for the MACS-separated cell fractions. The mineralization capacity of the osteogenic induced MSCA-1(+) cells compared with the MSCA-1(-) controls using MACS was 5-fold higher, whereas the same comparison after EasySep showed no significant differences between both fractions. By analyzing cell proliferation, we detected a significant difference between the proliferative potential of the osteogenic cells versus untreated cells after the MACS and EasySep separations. The differentiated cells after MACS separation adjusted their proliferative capacity, whereas the EasySep-separated cells failed to do so. The protein expression analysis showed small differences between the two separation methods. Our findings suggest that MACS is a more suitable separation method to isolate osteoprogenitors from the entire jaw periosteal cell population. PMID:23094035

Olbrich, Marcus; Rieger, Melanie; Reinert, Siegmar; Alexander, Dorothea

2012-01-01

230

Droplet-based magnetically activated cell separation: analysis of separation efficiency based on the variation of flow-induced circulation in a pendent drop  

Microsoft Academic Search

Under the assumption that separation efficiencies are mainly affected by the velocity of flow-induced circulation due to buffer\\u000a injection in a pendent drop, this paper describes an analysis of the separation efficiency of a droplet-based magnetically\\u000a activated cell separation (DMACS) system. To investigate the velocity of the flow-induced circulation, we supposed that numerous\\u000a flows in a pendent drop could be

Youngho Kim; Sang Ho Lee; Byungkyu Kim

2009-01-01

231

Fundamental study of cesium decontamination from soil by superconducting magnet  

NASA Astrophysics Data System (ADS)

The radioactive substances have been spread out all over the surrounding area of Fukushima Daiichi Nuclear Power Plant caused by the accident in March 2011. Decontamination and volume reduction of radioactive substances, especially cesium ion, are desired issue. This study proposed a decontamination method of the soil by the magnetic separation using superconducting magnet. Cesium ion was adsorbed by Prussian blue in the potassium iodide solution. We succeeded in separating selectively the cesium ion-adsorbed Prussian blue out of the liquid phase by high gradient magnetic separation. High recovery ratio of the Prussian blue was achieved by this method.

Igarashi, Susumu; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

2013-11-01

232

Lateral-driven continuous magnetophoretic separation of blood cells  

NASA Astrophysics Data System (ADS)

We present a method for the lateral-driven continuous magnetophoretic separation of red and white blood cells from peripheral whole blood, based on their native magnetic properties. The separation is achieved using a high-gradient magnetic field, caused by a ferromagnetic wire array inlaid on glass substrate. The wire array creates an even lateral magnetophoretic force on the whole area of the microchannel, improving the separation efficiency and throughput. When the flow rate and external magnetic flux were 20 ?l/h and 0.3 T, respectively, the microseparator continuously separated out 93.9% of red blood cells and 89.2% of white blood cells from the whole blood.

Jung, Jinhee; Han, Ki-Ho

2008-12-01

233

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

Microsoft Academic Search

A quadrupole magnetic field coupled with a flow in an axisymmetric annular thin channel is used for the continuous sorting of magnetic particles and of magnetically-labeled lymphocytes differing in magnetophoretic mobilities. The channel is composed of two concentric cylinders; in the thin annulus two flow splitters are placed at each extremity. The channel has two inlets and two outlets. Species

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

1999-01-01

234

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

Microsoft Academic Search

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 1.1×10?4 and 1.6×10?4m3kg?1, respectively, could be completely

Nicole Pamme; Jan C. T. Eijkel; Andreas Manz

2006-01-01

235

Magnetic Solid Sulfonic Acid Decorated with Hydrophobic Regulators: A Combinatorial and Magnetically Separable Catalyst for the Synthesis of ?-Aminonitriles.  

PubMed

A three-component, Strecker reaction of a series of aldehydes or ketones, amines, and trimethylsilyl cyanide for the synthesis of ?-aminonitriles in the presence of a catalytic amount of a magnetic solid sulfonic acid catalyst, Fe3O4@SiO2@Me&Et-PhSO3H under solvent-free conditions have been investigated. This catalyst, with a combination of hydrophobicity and acidity on the Fe3O4@SiO2 core-shell of the magnetic nanobeads, as well as its water-resistant property, enabled easy mass transfer and catalytic activity in the Strecker reaction. The catalyst was easily separated by an external magnet and the recovered catalyst was reused in 6 successive reaction cycles without any significant loss of activity. PMID:24932543

Mobaraki, Akbar; Movassagh, Barahman; Karimi, Babak

2014-07-14

236

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

PubMed

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

237

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

SciTech Connect

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

238

Optimizing the coating process of organic actinide extractants on magnetically assisted chemical separation particles.  

SciTech Connect

The coatings of ferromagnetic-charcoal-polymer microparticles (1-25 gm) with organic extractants specific for actinides were optimized for use in the magnetically assisted chemical separation (MACS) process. The organic extractants, octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) dissolved in tributyl phosphate (TBP), coated the particles when a carrier organic solvent was evaporated. Coated particles were heated in an oven overnight to drive off any remaining carrier solvent and fix the extractants on the particles. Partitioning coefficients for americium obtained with the coated particles routinely reached 3000-4000 ml g-1, approximately 10 times the separation efficiency observed with the conventional solvent extraction system using CMPO and TBP.

Buchholz, B. A.; Tuazon, H. E.; Kaminski, M. D.; Aase, S. B.; Nunez, L.; Vandegrift, G. F.; Chemical Engineering; LLNL; California State Polytechnic Univ. at Pomona; Univ. of Illinois; Univ. of Illinois at Chicago

1997-01-01

239

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

PubMed

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

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

2013-08-01

240

On chip cell separator using magnetic bead-based enrichment and depletion of various surface markers  

Microsoft Academic Search

This paper presents an on-chip magnetic cell sorting system for the sorting of cells based on a variety of surface markers.\\u000a A polymer lab on a chip integrated with an electroplated array of Ni\\/Fe permalloy has been designed, fabricated, and characterized\\u000a for the separation of cell substitutes at a variety of flow rates and incubation times. The system sequentially labels

Matthew D. Estes; Chong H. Ahn

2009-01-01

241

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

PubMed

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

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

2012-10-01

242

Antibody conjugated magnetic iron oxide nanoparticles for cancer cell separation in fresh whole blood  

Microsoft Academic Search

A highly efficient process using iron oxide magnetic nanoparticles (IO)-based immunomagnetic separation of tumor cells from fresh whole blood has been developed. The process involved polymer coated 30 nm IO that was modified with antibodies (Ab) against human epithelial growth factor receptor 2 (anti-HER2 or anti-HER2\\/neu) forming IO-Ab. HER2 is a cell membrane protein that is overexpressed in several types of

Hengyi Xu; Zoraida P. Aguilar; Lily Yang; Min Kuang; Hongwei Duan; Yonghua Xiong; Hua Wei; Andrew Wang

2011-01-01

243

High-efficiency bioaffinity separation of cells and proteins using novel thermoresponsive biotinylated magnetic nanoparticles  

Microsoft Academic Search

Thermoresponsive magnetic nanoparticles with an upper critical solution temperature (UCST) in aqueous solution were synthesized\\u000a for the first time. Named Therma-Max, the material was synthesized by redox copolymerization of N-acryloyl glycinamide with a monomer form of biotin using methacrylated dextran-magnetite. While the resulting Therma-Max\\u000a was completely dispersed at temperatures above the UCST (18°C) and could not be separated by a

Noriyuki Ohnishi; Hirotaka Furukawa; Hata Hideyuki; Jing-Ming Wang; Chung-Il An; Eiichiro Fukusaki; Kazunori Kataoka; Katsuhiko Ueno; Akihiko Kondo

2006-01-01

244

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

Microsoft Academic Search

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

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

2010-01-01

245

Magnetization reversal and nanoscopic magnetic-phase separation in La1-x Srx CoO3  

NASA Astrophysics Data System (ADS)

The doped perovskite cobaltite La1-x Srx CoO3 (LSCO) has been advanced as a model system for studying intrinsic magnetic phase separation. We have employed a first-order reversal curve (FORC) method to probe the amount of irreversible switching in bulk polycrystalline LSCO as a function of Sr doping, field cooling procedure, and temperature. The value of the FORC distribution ? is used as a measure of the extent of irreversible switching. For x<0.18 , the small values of ? and its ridgelike distribution along local coercivity ( Hc ) and zero bias ( Hb ) are characteristic of noninteracting single domain particles. This is consistent with the formation of an array of isolated nanoscopic ferromagnetic clusters, as observed in previous work. For x?0.18 , the much larger values of ? , the tilting of its distribution towards negative bias field, and the emergence of regions with negative ? are consistent with increased long-range ferromagnetic ordering. The FORC distributions display little dependence on the cooling procedure. With increasing temperature, the fraction of irreversible switching determined from the FORC distribution follows closely the ferromagnetic phase fraction measured by La nuclear magnetic resonance. Our results furthermore demonstrate that the FORC method is a valuable first-pass characterization tool for magnetic-phase separation.

Davies, Joseph E.; Wu, J.; Leighton, C.; Liu, Kai

2005-10-01

246

New monodisperse magnetic polymer microspheres biofunctionalized for enzyme catalysis and bioaffinity separations.  

PubMed

Magnetic macroporous PGMA and PHEMA microspheres containing carboxyl groups are synthesized by multi-step swelling and polymerization followed by precipitation of iron oxide inside the pores. The microspheres are characterized by SEM, IR spectroscopy, AAS, and zeta-potential measurements. Their functional groups enable bioactive ligands of various sizes and chemical structures to couple covalently. The applicability of these monodisperse magnetic microspheres in biospecific catalysis and bioaffinity separation is confirmed by coupling with the enzyme trypsin and huIgG. Trypsin-modified magnetic PGMA-COOH and PHEMA-COOH microspheres are investigated in terms of their enzyme activity, operational and storage stability. The presence of IgG molecules on microspheres is confirmed. PMID:22411761

Horák, Daniel; Ku?erová, Jana; Korecká, Lucie; Jankovi?ová, Barbora; Palar?ík, Ji?í; Mikulášek, Petr; Bílková, Zuzana

2012-05-01

247

Phase transitions in a ferrofluid at magnetic-field-induced microphase separation.  

PubMed

In the presence of a magnetic field applied perpendicular to a thin sample layer, a suspension of magnetic colloidal particles (ferrofluid) can form spatially modulated phases with a characteristic length determined by the competition between dipolar forces and short-range forces opposing density variations. We introduce models for thin-film ferrofluids in which magnetization and particle density are viewed as independent variables and in which the nonmagnetic properties of the colloidal particles are described either by a lattice-gas entropy or by the Carnahan-Starling free energy. Our description is particularly well suited to the low-particle-density regions studied in many experiments. Within mean-field theory, we find isotropic, hexagonal and stripe phases, separated in general by first-order phase boundaries. PMID:11690032

Lacoste, D; Lubensky, T C

2001-10-01

248

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

SciTech Connect

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

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

2013-11-01

249

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

250

Magnetic field and gradient analysis around matrix for HGMS  

NASA Astrophysics Data System (ADS)

A High Gradient Magnetic Separator (HGMS) uses matrix to make high magnetic field gradient so that ferro- or para-magnetic particles can be attracted to them by high magnetic force. These matrixes are usually composed of stainless wires having high magnetization characteristics. This paper deals with superconducting HGMS which is aimed for purifying wastewater by using stainless steel matrix. Background magnetic field up to 6 T is generated by a superconducting solenoid and the stainless steel matrix are arranged inside of the solenoid. In order to calculate magnetic forces exerting on magnetic particles in wastewater, it is important to calculate magnetic field and magnetic field gradient those are proportional to the magnetic force acting on the particle. So we presents magnetic field distribution analysis result and estimates how many times of magnetic force will act on a particle when the matrix are arranged or not.

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

2010-11-01

251

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

SciTech Connect

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

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

1992-02-01

252

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

NASA Astrophysics Data System (ADS)

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

253

Preparation of magnetic molecularly imprinted polymers for separating rutin from Chinese medicinal plants.  

PubMed

The preparation of magnetic molecularly imprinted polymers (MMIPs) which can be used for the separation and purification of rutin from Chinese medicinal plants has been proposed. By applying the improved co-precipitation method, magnetic Fe(3)O(4) particles were easily prepared, followed by the modification of TEOS and functionalization with -CH=CH(2). Using functionalized Fe(3)O(4) particles as the magnetic cores, rutin as the template, and acrylamide as the functional monomer, MMIPs were synthesized by surface-imprinted polymerization under the protection of nitrogen gas and successive mechanical stirring at 60 °C for 24 h. Magnetic non-molecularly imprinted polymers (MNIPs) were also prepared with the same synthesis procedure as with MMIPs only without the presence of rutin. Magnetic particles were characterized by FT-IR, XRD, and TG analysis. And the selectivity of MMIPs was also investigated in detail. In addition, the performance of the MMIPs for the adsorption of rutin in the analysis of Chinese medicinal plants was assessed. The mean recoveries were 84.33% (RSD: 3.22%, n = 3) for Saururus chinensis (Lour.) Bail and 85.20% (RSD: 3.58%, n = 3) for Flos Sophorae, respectively, which showed that the prepared MMIPs with many advantages possess the value of practical application. PMID:22489285

Zeng, Huan; Wang, Yuzhi; Nie, Chan; Kong, Jinhuan; Liu, Xiaojie

2012-05-21

254

Formation and properties of magnetic chains for 100 nm nanoparticles used in separations of molecules and cells  

NASA Astrophysics Data System (ADS)

Optical observations of 100 nm metallic magnetic nanoparticles are used to study their magnetic field induced self assembly. Chains with lengths of tens of microns are observed to form within minutes at nanoparticle concentrations 10 10/mL. Chain rotation and magnetophoresis are readily observed, and SEM reveals that long chains are not simple single particle filaments. Similar chains are detected for several 100 nm commercial bio-separation nanoparticles. We demonstrate the staged magnetic condensation of different types of nanoparticles into composite structures and show that magnetic chains bind to immuno-magnetically labeled cells, serving as temporary handles which allow novel magnetic cell manipulations.

Wilson, Robert J.; Hu, Wei; Fu, Cheryl Wong Po; Koh, Ai Leen; Gaster, Richard S.; Earhart, Christopher M.; Fu, Aihua; Heilshorn, Sarah C.; Sinclair, Robert; Wang, Shan X.

2009-05-01

255

Measured and theoretical characterization of the RF properties of stacked, high-gradient insulator material  

SciTech Connect

Recent high-voltage breakdown experiments of periodic metallic-dielectric insulating structures have suggested several interesting high-gradient applications. One such area is the employment of high-gradient insulators in high-current, electron-beam, accelerating induction modules. For this application, the understanding of the rf characteristics of the insulator plays an important role in estimating beam-cavity interactions. In this paper, we examine the rf properties of the insulator comparing simulation results with experiment. Different insulator designs are examined to determine their rf transmission properties in gap geometries.

Houck, T. L., LLNL

1997-05-09

256

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

PubMed

A novel magnetic nanoadsorbent (CMCD-APTS-MNPs) containing the superparamagnetic and molecular recognition properties was synthesized by grafting carboxymethyl-?-cyclodextrin (CM-?-CD) on 3-aminopropyltriethoxysile (APTS) modified Fe(3)O(4) nanoparticles. The feasibility of using CMCD-APTS-MNPs as magnetic nanoadsorbent for selective adsorption of adenosine (A) and guanosine (G) based on inclusion and molecular recognition was demonstrated. The as-synthesized magnetic nanoparticles were characterized by TEM, FTIR and TGA analyses. The effects of pH and initial nucleoside concentrations on the adsorption behavior were studied. The complexation of CMCD-APTS-MNPs with both nucleosides was found to follow the Langmuir adsorption isotherm. The CMCD-APTS-MNPs showed a higher adsorption ability and selectivity for G than A under identical experimental conditions, which results from the ability of selective binding and recognition of the immobilized CM-?-CD towards G. The driving force of the separation between G and A is through the different weak interaction with grafted CM-?-CD, i.e., hydrogen bond interaction, which is evidenced by different inclusion equilibrium constants and FTIR analyses of inclusion complexes between grafted cyclodextrin and the guest molecules. Our results indicated that this nanoadsorbent would be a promising tool for easy, fast and selective separation, analysis of nucleosides and nucleotides in biological samples. PMID:22177539

Badruddoza, A Z M; Junwen, L; Hidajat, K; Uddin, M S

2012-04-01

257

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

PubMed

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

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

2014-04-14

258

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

NASA Astrophysics Data System (ADS)

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

259

Upgrading of Low-Grade Manganese Ore by Selective Reduction of Iron Oxide and Magnetic Separation  

NASA Astrophysics Data System (ADS)

The utilization of low-grade manganese ores has become necessary due to the intensive mining of high-grade ores for a long time. In this study, calcined ferruginous low-grade manganese ore was selectively reduced by CO, which converted hematite to magnetite, while manganese oxide was reduced to MnO. The iron-rich component was then separated by magnetic separation. The effects of the various reduction parameters such as particle size, reduction time, temperature, and CO content on the efficiency of magnetic separation were studied by single-factor experiments and by a comprehensive full factorial experiment. Under the best experimental conditions tested, the manganese content in the ore increased from around 36 wt pct to more than 44 wt pct, and almost 50 wt pct of iron was removed at a Mn loss of around 5 pct. The results of the full factorial experiments allowed the identification of the significant effects and yielded regression equations for pct Fe removed, Mn/Fe, and pct Mn loss that characterize the efficiency of the upgrading process.

Gao, Yubo; Olivas-Martinez, M.; Sohn, H. Y.; Kim, Hang Goo; Kim, Chan Wook

2012-12-01

260

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

SciTech Connect

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

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

2007-09-07

261

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

PubMed

We demonstrate the suitability of polarization microscopy to study the recently discovered (parallel) nematic-(perpendicular) nematic phase separation. This novel type of phase transition is induced by applying an external magnetic field to a nematic liquid crystal of boardlike colloidal goethite and is due to an interplay between the intrinsic magnetic properties of goethite and the collective effect of liquid crystal formation. It is shown that the intense ochre colour of goethite does not preclude the use of polarization microscopy and interference colours, and that dichroism can give valuable qualitative information on the nature of the phases, their anchoring and their sedimentation and order parameter profiles. We also apply these techniques to study 'nematic-nematic tactoids': nematic droplets sedimenting within a nematic medium with mutually perpendicular orientations. PMID:21525548

van den Pol, E; Verhoeff, A A; Lupascu, A; Diaconeasa, M A; Davidson, P; Dozov, I; Kuipers, B W M; Thies-Weesie, D M E; Vroege, G J

2011-05-18

262

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

PubMed Central

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

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

263

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

NASA Astrophysics Data System (ADS)

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

Kitahara, Tadashi; Honda, Satoshi

2011-06-01

264

Rapid and selective separation for mixed proteins with thiol functionalized magnetic nanoparticles  

PubMed Central

Thiol group functionalized silica-coated magnetic nanoparticles (Si-MNPs@SH) were synthesized for rapid and selective magnetic field-based separation of mixed proteins. The highest adsorption efficiencies of binary proteins, bovine serum albumin (BSA; 66 kDa; pI = 4.65) and lysozyme (LYZ; 14.3 kDa; pI = 11) were shown at the pH values corresponding to their own pI in the single-component protein. In the mixed protein, however, the adsorption performance of BSA and LYZ by Si-MNPs@SH was governed not only by pH but also by the molecular weight of each protein in the mixed protein.

2012-01-01

265

Adaptive separation of regular and irregular magnetic activity for K indices  

NASA Astrophysics Data System (ADS)

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

Walker, J. K.

1987-10-01

266

Desulphurization of lignites by slow, fast, and flash pyrolysis and high intensity dry magnetic separation  

SciTech Connect

Slow, fast and flash pyrolysis followed by high intensity dry magnetic (HIDM) separation experiments were conducted to obtain improved solid fuels. Pyrolysis experiments were performed in three different apparatus, and important parameters of processes, temperature, particle size, residence time and heating rate were studied to determine the optimum conditions. Desulphurization of lignites by flash pyrolysis is more successful than slow and fast pyrolysis. At optimum conditions of pyrolysis, up to 58.15, 60.24, and 62.31% sulphur reductions were obtained in slow, fast and flash pyrolysis, respectively. Char, obtained from the pyrolysis experiments, was further cleaned by a Permroll HIDM separator. Sulphur reduction enhanced up to 82.68, 84.40, and 86.55% in the char of slow, fast and flash pyrolysis, respectively.

Koca, H.; Kockar, O.M.; Koca, S. [Anadolu University, Eskisehir (Turkey). Porsuk Technical College

2007-07-01

267

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

NASA Astrophysics Data System (ADS)

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

Song, Yu; Tao, Ling; Shen, Xiangchun

2012-07-01

268

Utilization of magnetic and electrostatic separation in the recycling of printed circuit boards scrap.  

PubMed

The progress of the technology is directly related to the growth of production and consumption of electrical/electronics equipment, especially of personal computers. This type of equipment has a relatively short average lifetime, 2-3 years. The amount of defective or obsolete equipment has been increasing substantially; consequently its disposition and/or recycling should be studied. In this work, printed circuit boards, which are used in personal computers, were studied in order to recover the metals in the circuit boards through mechanical processing, such as crushing, screening, as well as magnetic and electrostatic separation. The results obtained demonstrate the feasibility of using these processes to separate metal fractions from polymers and ceramics, and that it is possible to obtain a fraction concentrated in metals containing more than 50% on average of copper, 24% of tin and 8% of lead. PMID:15681180

Veit, H M; Diehl, T R; Salami, A P; Rodrigues, J S; Bernardes, A M; Tenório, J A S

2005-01-01

269

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

PubMed

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

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

2014-04-01

270

Orientation and Strain Dependence of the Magnetic Phase Separation at Perovskite Cobaltite Interfaces  

NASA Astrophysics Data System (ADS)

We recently showed that the degraded magnetic and electronic properties in very thin STO(001)/La1-xSrxCoO3 films is due to a form of magnetic phase separation. This is primarily due to the strain driven accumulation of O vacancies near the interface. In this work we demonstrate how this understanding allows us to engineer these interfacial properties via crystallographic orientation and strain control. Using PNR, magnetometry and transport, we show how this degradation can be significantly mitigated by using LAO(001) and STO(110) substrates cf. STO(001). PNR on 400å x=0.28 films reveals an interfacial layer with suppressed magnetism on all three substrates. However, while this layer is 150å on STO(001), it extends at most to 30å on LAO(001) and STO(110). Transport measurements on x=0.5 films show that at a thickness of ˜ 55å, films on STO(110) and LAO(001) exhibit AMR whereas films on STO(001) are dominated by inter-cluster GMR. Finally, thickness dependent magnetometry shows that the magnetic order deteriorates more quickly on STO(001) than on LAO(001) and STO(110). Our work thus opens up a possible new route to tailor interfacial magneto-electronic properties in oxide heterostructures.

Bose, S.; Sharma, M.; Torija, M. A.; Gazquez, J.; Varela, M.; Ambaye, H.; Goyette, R.; Lauter, V.; Fitzsimmons, M. R.; Schmitt, J.; Leighton, C.

2013-03-01

271

Initial exploration of application of open-gradient magnetic separation of coal to beneficiation of liquefaction feeds  

Microsoft Academic Search

Finely divided multi-component solids can be separated into multiple fractions by Open-Gradient Magnetic Separation if differences in magnetic susceptibility exist among the components. This technique has now been applied to several crushed coals, in particular to the 30-100 mesh cut. Coal fractions have been characterized by petrographic, mineralogical, and analytical data. As one proceeds from the most diamagnetic to the

M. L. Poutsma; L. A. Harris; E. C. Hise; R. M. Wham; J. E. Wortman

1983-01-01

272

Habitat modeling in high-gradient streams: the mesoscale approach and application.  

PubMed

This study aimed to set out a new methodology for habitat modeling in high-gradient streams. The methodology is based on the mesoscale approach of the MesoHABSIM simulation system and can support the definition and assessment of environmental flow and habitat restoration measures. Data from 40 study sites located within the mountainous areas of the Valle d'Aosta, Piemonte and Liguria regions (Northwest Italy) were used in the analysis. To adapt MesoHABSIM to high-gradient streams, we first modified the data collection strategy to address the challenging conditions of surveys by using GIS and mobile mapping techniques. Secondly, we built habitat suitability models at a regional scale to enable their transferability among different streams with different morphologies. Thirdly, due to the absence of stream gauges in headwaters, we proposed a possible way to simulate flow time series and, therefore, generate habitat time series. The resulting method was evaluated in terms of time expenditure for field data collection and habitat-modeling potentials, and it represents a specific improvement of the MesoHABSIM system for habitat modeling in high-gradient streams, where other commonly used methodologies can be unsuitable. Through its application at several study sites, the proposed methodology adapted well to high-gradient streams and allowed the: (1) definition of fish habitat requirements for many streams simultaneously, (2) modeling of habitat variation over a range of discharges, and (3) determination of environmental standards for mountainous watercourses. PMID:24988781

Vezza, Paolo; Parasiewicz, Piotr; Spairani, Michele; Comoglio, Claudio

2014-06-01

273

A THz Coaxial Two-Channel Dielectric Wakefield Structure for High Gradient Acceleration  

SciTech Connect

A coaxial two-channel dielectric wakefield structure is examined for use as a high gradient accelerator. A THz design, having radius {approx}1 mm, is shown to provide GeV/m--level acceleration gradient, high transformer ratio, and stable accelerated bunch motion when excited by a stable-moving 5-GeV 6-nC annular drive bunch.

Marshall, T. C. [Columbia University, New York, NY (United States); Omega-P, Inc., New Haven, CT (United States); Sotnikov, G. V. [Omega-P, Inc., New Haven, CT (United States); NSC Kharkov Institute of Physics and Technology, Kharkov (Ukraine); Hirshfield, J. L. [Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States)

2010-11-04

274

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

National Technical Information Service (NTIS)

There is growing demand from the industrial and research communities for high gradient, compact RF accelerating structures. The commonly used S-band SLAC-type structure has an operating gradient of only about 20 MV/m; while much higher operating gradients...

A. Murokh J. Rosenzweig L. Faillace P. Frigola R. Agustsson V. Dolgashev

2012-01-01

275

Formation and properties of magnetic chains for 100 nm nanoparticles used in separations of molecules and cells.  

PubMed

Optical observations of 100 nm metallic magnetic nanoparticles are used to study their magnetic field induced self assembly. Chains with lengths of tens of microns are observed to form within minutes at nanoparticle concentrations of 10(10) per mL. Chain rotation and magnetophoresis are readily observed, and SEM reveals that long chains are not simple single particle filaments. Similar chains are detected for several 100 nm commercial bio-separation nanoparticles. We demonstrate the staged magnetic condensation of different types of nanoparticles into composite structures and show that magnetic chains bind to immunomagnetically labeled cells, serving as temporary handles which allow novel magnetic cell manipulations. PMID:20161001

Wilson, Robert J; Hu, Wei; Fu, Cheryl Wong Po; Koh, Ai Leen; Gaster, Richard S; Earhart, Christopher M; Fu, Aihua; Heilshorn, Sarah C; Sinclair, Robert; Wang, Shan X

2009-05-01

276

Formation and properties of magnetic chains for 100 nm nanoparticles used in separations of molecules and cells  

PubMed Central

Optical observations of 100 nm metallic magnetic nanoparticles are used to study their magnetic field induced self assembly. Chains with lengths of tens of microns are observed to form within minutes at nanoparticle concentrations of 1010 per mL. Chain rotation and magnetophoresis are readily observed, and SEM reveals that long chains are not simple single particle filaments. Similar chains are detected for several 100 nm commercial bio-separation nanoparticles. We demonstrate the staged magnetic condensation of different types of nanoparticles into composite structures and show that magnetic chains bind to immunomagnetically labeled cells, serving as temporary handles which allow novel magnetic cell manipulations.

Wilson, Robert J.; Hu, Wei; Fu, Cheryl Wong Po; Koh, Ai Leen; Gaster, Richard S.; Earhart, Christopher M.; Fu, Aihua; Heilshorn, Sarah C.; Sinclair, Robert; Wang, Shan X.

2009-01-01

277

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

DOEpatents

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

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

1999-01-01

278

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

DOEpatents

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

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

1999-07-20

279

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

PubMed

Magnetic fractions (MFs) in fly ashes from eight coal-burning power plants were extracted by magnetic separation procedure. Their mineralogy and potential leachability of heavy metals were analyzed using rock magnetism, X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX) and leaching procedures (toxicity characteristics leaching procedure by the United States Environmental Protection Agency, TCLP, and gastric juice simulation test, GJST). Results show that the MFs in the fly ashes range between 2.2 and 16.3wt%, and are generally composed of magnetite, hematite, quartz and mullite. Thermomagnetic analysis and SEM/EDX indicate that the main magnetic carrier magnetite is substituted with small amounts of impure ions, and its structures are featured by rough, dendritic and granular iron spherules. The MFs are found to be rich in Fe, Mn, Cr, Cu, Cd and Pb. Compared with the non-magnetic fractions (NMFs), the MFs have about 5 times higher iron, and 1.6 times higher Mn, Cr, Cu and Cd concentrations. The TCLP test shows that the TCLP-extractable Cr, Cu, and Pb concentrations in the MFs are higher than those in the NMFs, while the TCLP-extractable Cd concentration in the MFs and NMFs is below the detection limit (<0.1mg/L). The GJST-extractable Cd, Cr, Cu, and Pb concentrations in the MFs are higher those in the NMFs. No significant difference in the leachability ratio of Cr, Cu and Pb with TCLP and GJST is found in the MFs and NMFs. However, the GJST test showed that Pb has higher leachability in MFs than that in NMFs. The leachability ratio of heavy metals has an order of Cu>Cr>Pb>Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment. PMID:19380201

Lu, S G; Chen, Y Y; Shan, H D; Bai, S Q

2009-09-30

280

Quantification of Non-Specific Binding of Magnetic Micro and Nano particles using Cell Tracking Velocimetry: Implication for magnetic cell separation and detection  

PubMed Central

The maturation of magnetic cell separation technology places increasing demands on magnetic cell separation performance. While a number of factors can cause suboptimal performance, one of the major challenges can be non-specific binding of magnetic nano or micro particles to non-targeted cells. Depending on the type of separation, this non-specific binding can have a negative effect on the final purity, the recovery of the targeted cells, or both. In this work, we quantitatively demonstrate that non-specific binding of magnetic nanoparticles can impart a magnetization to cells such that these cells can be retained in a separation column and thus negatively impact the purity of the final product and the recovery of the desired cells. Through experimental data and theoretical arguments, we demonstrate that the number of MACS magnetic particles needed to impart a magnetization that is sufficient to causes non-targeted cells to be retained in the column to be on the order of 500 to 1,000 nanoparticles. This number of non-specifically bound particles was demonstrated experimentally with an instrument, cell tracking velocimeter, CTV, and it is demonstrated that the sensitivity of the CTV instrument for Fe atoms contained in magnetic nanoparticles on the order of 1 × 10?15 g/mL of Fe.

Chalmers, J.J.; Xiong, Y.; Jin, X.; Shao, M.; Tong, X.; Farag, S.; Zborowski, M.

2012-01-01

281

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

SciTech Connect

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

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

1994-12-01

282

Synthesis of magnetic ion-imprinted composites and selective separation and preconcentration of U(VI).  

PubMed

The U(VI) magnetic ion-imprinted composite (MIIC) with a uniform core-shell structure for the selective separation and preconcentration of U(VI) was prepared by copolymerization of a ternary complex of uranyl ions with 4-vinylpyridine (4-VP) and acrylamide in the presence of 2,2'-azobisisobutyronitrile. The sorption of U(VI) on the MIIC from aqueous solution was evaluated. The maximum sorption capacity of MIIC for U(VI) was 354.85 mg g(-1), which was much higher than that of the magnetic nonimprinted composite. The MIIC could be recovered by desorbing the U(VI)-loaded MIIC with 0.5 mol L(-1) HNO3, and the surface morphology of MIIC after five consecutive sorption/desorption cycles was significantly damaged. The competitive sorption experiments showed that the MIIC had a desirable selectivity for U(VI) over a range of competing metal ions. The MIIC may be a promising sorbent material for the selective separation and preconcentration of U(VI). PMID:24667936

Liu, Mancheng; Chen, Changlun; Wen, Tao; Wang, Xiangke

2014-05-21

283

High-frequency magnetic field probe for determination of interface levels in separation tanks  

NASA Astrophysics Data System (ADS)

There are many principles for interface level detection in separation tanks based on capacitance, ultra sound, microwave, nuclear radiation etc. These principles work well in many situations, in others they fail. The high frequency magnetic field principle works in most of the situations that will occur in separation tanks for crude oils for detection of the clean water level, the layers of water continuous water/oil emulsion and the oil continuous oil/water emulsion, the oil level, the thickness of the foam layer and the gas. When a coil is dipped into a fluid its electrical impedance will be dependent on the characteristics of the fluid. If the material is electrical conductive the impedance of the coil will be reduced due to the eddy currents induced in the material, setting up a magnetic field directed against the field generated by the coil. The inductance will increase but still remain low also in the water continuous water/oil emulsion zone, but will rapidly increase in the oil continuous oil/water emulsion zone. In pure crude oil the inductance will be high and even higher in gas. The coil inductance is measured by connecting the coil to a LC-oscillator.

Hammer, Erling; Abro, Eirik; Cimpan, Emil; Yan, Guanqun

2001-02-01

284

Heterogeneous post-column immunoreaction detection using magnetized beads and a laboratory-constructed electromagnetic separator.  

PubMed

The nature of immune reactors allows development of quantitative analytical methods that are highly selective and can often be used directly with complex biological matrixes such as blood, plasma or urine. A major limitation of immunoassay is that antibodies are sometimes unable to discriminate structurally similar species such as drug metabolites and synthetic analogs. The problem associated with the lack of discrimination can be circumvented by coupling immunoassay with liquid chromatography post-column. The most commonly used separation method in post-column immunoreaction detection is the affinity column. Affinity columns may create undesired effects such as a compromise of the chromatographic separation efficiency, the requirement for an antibody with fast reaction kinetics and the need for flushing the column. This paper reports a post-column immunoreaction detection system coupled with a laboratory-constructed on-line magnetic separation flow chamber that is designed to overcome these problems. The system uses disposable magnetic beads as a solid-phase support for separation that can be easily removed from the system. The model analytes chosen for this study were digoxin and its metabolites due to the commercial availability of monoclonal antibodies for these compounds. Digoxin was separated using a chromatographic method prior to being interfaced through a liquid handler system to the immunoreactor. Compatibility of the HPLC mobile phase was determined to be acceptable with a mixing ratio of 1:3 between the LC fraction and immunoreagent solution. The dynamic range of the calibration curve in digoxin-spiked phosphate buffer was found to be 0.25-12 ng/ml and a quadratic fit was found to provide the best fit to the data with a correlation coefficient of 0.9974. The residual error for all standards was less than 15%. The percentage RSDs for the two controls, 2 and 10 ng/ml, were 6.88 and 4.82% (n = 6) and the percentage errors were 7.07 and -6.89% (n = 6), respectively. PMID:12717800

Tang, Zhe; Karnes, H Thomas

2003-01-01

285

Phase separation in nematic microemulsions probed by one-dimensional spectroscopic deuteron magnetic resonance microimaging  

NASA Astrophysics Data System (ADS)

We present a study of a phase-transition-driven separation in microemulsions of nanosized lyotropic inverse micelles and thermotropic liquid crystal pentylcyanobiphenyl (5CB) with 5%, 8%, and 15% micelle concentration. Using deuteron nuclear magnetic resonance (DNMR) microimaging in combination with conventional microscopy as well as ac calorimetry, we demonstrate a phase separation scenario in which micelles are expelled from the nematic phase during the I-N conversion. Due to a difference in density the micelle-rich isotropiclike phase spatially separates from the micelle-free nematic phase. A relatively sharp interface, formed between the two phases, can be controllably shifted by temperature-induced conversion between the phases. Once expelled, micelles do not remix into the nematic phase, whereas in the isotropic state their remixing takes place over several days. Temperature dependence of the linewidth of isotropic spectral component has been analyzed in terms of molecular reorientations mediated by translational displacements, assuming isotropically distributed directors of nanosized nematic domains. With our results, the existence of the proposed transparent nematic state cannot be completely ruled out. However, if present, the nematic order in such a phase must be extremely low.

Lebar, Andrija; Kutnjak, Zdravko; Tanaka, Hajime; Zalar, Boštjan; Žumer, Slobodan

2008-09-01

286

Phase separation in nematic microemulsions probed by one-dimensional spectroscopic deuteron magnetic resonance microimaging.  

PubMed

We present a study of a phase-transition-driven separation in microemulsions of nanosized lyotropic inverse micelles and thermotropic liquid crystal pentylcyanobiphenyl (5CB) with 5%, 8%, and 15% micelle concentration. Using deuteron nuclear magnetic resonance (DNMR) microimaging in combination with conventional microscopy as well as ac calorimetry, we demonstrate a phase separation scenario in which micelles are expelled from the nematic phase during the I-N conversion. Due to a difference in density the micelle-rich isotropiclike phase spatially separates from the micelle-free nematic phase. A relatively sharp interface, formed between the two phases, can be controllably shifted by temperature-induced conversion between the phases. Once expelled, micelles do not remix into the nematic phase, whereas in the isotropic state their remixing takes place over several days. Temperature dependence of the linewidth of isotropic spectral component has been analyzed in terms of molecular reorientations mediated by translational displacements, assuming isotropically distributed directors of nanosized nematic domains. With our results, the existence of the proposed transparent nematic state cannot be completely ruled out. However, if present, the nematic order in such a phase must be extremely low. PMID:18851055

Lebar, Andrija; Kutnjak, Zdravko; Tanaka, Hajime; Zalar, Bostjan; Zumer, Slobodan

2008-09-01

287

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

PubMed

Islet cell transplantation is a promising option for the restoration of normal glucose homeostasis in patients with type 1 diabetes. Because graft volume is a crucial issue in islet transplantations for patients with diabetes, we evaluated a new method for increasing functional tissue yield in xenogeneic grafts of encapsulated islets. Islets were labeled with three different superparamagnetic iron oxide nano particles (SPIONs; dextran-coated SPION, siloxane-coated SPION, and heparin-coated SPION). Magnetic separation was performed to separate encapsulated islets from the empty capsules, and cell viability and function were tested. Islets labeled with 1000 ?g Fe/ml dextran-coated SPIONs experienced a 69.9% reduction in graft volume, with a 33.2% loss of islet-containing capsules. Islets labeled with 100 ?g Fe/ml heparin-coated SPIONs showed a 46.4% reduction in graft volume, with a 4.5% loss of capsules containing islets. No purification could be achieved using siloxane-coated SPIONs due to its toxicity to the primary islets. SPION labeling of islets is useful for transplant purification during islet separation as well as in vivo imaging after transplantation. Furthermore, purification of encapsulated islets can also reduce the volume of the encapsulated islets without impairing their function by removing empty capsules. PMID:23789985

Mettler, Esther; Trenkler, Anja; Feilen, Peter J; Wiegand, Frederik; Fottner, Christian; Ehrhart, Friederike; Zimmermann, Heiko; Hwang, Yong Hwa; Lee, Dong Yun; Fischer, Stefan; Schreiber, Laura M; Weber, Matthias M

2013-01-01

288

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

Microsoft Academic Search

A technology that could physically remove substances from the blood such as biological, chemical, or radiological toxins could dramatically improve treatment of disease. One method in development proposes to use magnetic-polymer spheres to selectively bind toxins and remove them by magnetic filtration. Although magnetic filtration is a developed technology, the clinical boundary conditions described here require a new filter design.

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

2007-01-01

289

Separation of Plasmodium falciparum late stage-infected erythrocytes by magnetic means.  

PubMed

Unlike other Plasmodium species, P. falciparum can be cultured in the lab, which facilitates its study (1). While the parasitemia achieved can reach the ?40% limit, the investigator usually keeps the percentage at around 10%. In many cases it is necessary to isolate the parasite-containing red blood cells (RBCs) from the uninfected ones, to enrich the culture and proceed with a given experiment. When P. falciparum infects the erythrocyte, the parasite degrades and feeds from haemoglobin (2, 3). However, the parasite must deal with a very toxic iron-containing haem moiety (4, 5). The parasite eludes its toxicity by transforming the haem into an inert crystal polymer called haemozoin (6, 7). This iron-containing molecule is stored in its food vacuole and the metal in it has an oxidative state which differs from the one in haem (8). The ferric state of iron in the haemozoin confers on it a paramagnetic property absent in uninfected erythrocytes. As the invading parasite reaches maturity, the content of haemozoin also increases (9), which bestows even more paramagnetism on the latest stages of P. falciparum inside the erythrocyte. Based on this paramagnetic property, the latest stages of P. falciparum infected-red blood cells can be separated by passing the culture through a column containing magnetic beads. These beads become magnetic when the columns containing them are placed on a magnet holder. Infected RBCs, due to their paramagnetism, will then be trapped inside the column, while the flow-through will contain, for the most part, uninfected erythrocytes and those containing early stages of the parasite. Here, we describe the methodology to enrich the population of late stage parasites with magnetic columns, which maintains good parasite viability (10). After performing this procedure, the unattached culture can be returned to an incubator to allow the remaining parasites to continue growing. PMID:23486405

Coronado, Lorena Michelle; Tayler, Nicole Michelle; Correa, Ricardo; Giovani, Rita Marissa; Spadafora, Carmenza

2013-01-01

290

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

SciTech Connect

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

Nunez', L.; Kaminsky', M.D.,; Crawford, C.; Ritter, J.A.

1999-12-31

291

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

SciTech Connect

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

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

2010-01-01

292

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

SciTech Connect

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

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

1993-01-01

293

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

SciTech Connect

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

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

2012-06-11

294

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

SciTech Connect

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

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

2010-11-04

295

Wave-driven rotation and mass separation in rotating magnetic mirrors  

NASA Astrophysics Data System (ADS)

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

Fetterman, Abraham J.

296

X-band photoinjector\\/high gradient accelerator based light source  

Microsoft Academic Search

A compact source of monochromatic ultrashort X-ray pulses tunable in the 10 to 85 keV range is obtained from Compton scattering of intense sub-picosecond optical pulses with relativistic electron bunches. Unlike conventional large National Laboratory scale synchrotron radiation sources, the relativistic Compton device utilizes compact vacuum components including a single X-band klystron, a 5.5 cell photoinjector, and a 1.05-meter, high-gradient

J. P. Heritage; A. E. Vlieks; C. DeStefano; W. J. Frederick; G. Caryotakis; D. Martin; E. Landahl

2004-01-01

297

High-gradient studies on 11. 4 GHz copper accelerator structures  

Microsoft Academic Search

This paper is a progress report on studies carried out at SLAC to assess the high-gradient behavior of 11.4 GHz copper accelerator structures for future linear colliders. the structures which have been examined in the last year are a 7-cavity standing-wave (SW) section and a 30-cavity traveling-wave (TW)section. Both structures are of the constant-impedance uniform-aperture type with a 2μ\\/3 phase

J. W. Wang; R. A. Curry; H. Deruyter; H. A. Hoag; R. F. Koontz; G. A. Loew; A. Menegat; R. H. Miller; R. D. Ruth; A. E. Vlieks; C. Yoneda

1992-01-01

298

UltraHigh Gradient Compact S-Band Linac for Laboratory and Industrial Applications  

Microsoft Academic Search

There is growing demand from the industrial and research communities for high gradient, compact RF accelerating structures. The commonly used S-band SLAC-type structure has an operating gradient of only about 20 MV\\/m; while much higher operating gradients (up to 70 MV\\/m) have been recently achieved in X-band, as a consequence of the substantial efforts by the Next Linear Collider (NLC)

Faillace

2012-01-01

299

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

SciTech Connect

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

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

2012-04-24

300

High-gradient cavity beat-wave accelerator at W-band  

Microsoft Academic Search

Pulsed rf heating is a fundamental limit on high-gradient acceleration in copper structures. Reduction of pulsed heating is favored by a short exposure time for the copper; yet in conventional accelerators, efficiency requires an exposure time of order of the cavity fill time. At the W-Band, the cavity beat-wave transformer concept permits efficient energy transfer to resonant accelerating modes on

D. H. Whittum; H. Henket; P. J. Chou

1997-01-01

301

A new high-gradient correction quadrupole for the Fermilab luminosity upgrade  

Microsoft Academic Search

Special superconducting correction quadrupoles are needed for the luminosity upgrade of the Fermilab Tevatron Collider. These correctors are part of the low-beta system for the interaction regions at B0 and D0. The requirements are high gradient and low current. A quadrupole has been designed that meets the operating gradient of 0.63 T\\/cm at 1086 A. The one-layer quadrupole is wound

P. Mantsch; J. Carson; A. Riddiford; M. J. Lamm

1989-01-01

302

Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures  

SciTech Connect

The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

Byer, Robert L.

2013-11-07

303

Evaluation of a glassless photographic film scanner for high-gradient radiochromic film dosimetry.  

PubMed

This study evaluates the performance of the Nikon Coolscan 9000 ED film scanner for high-gradient radiochromic film dosimetry. As a reference for comparison, analogue experiments were performed on the Epson Expression 10000XL flatbed scanner. Based on these results, a dosimetric protocol was established for the Nikon scanner and its overall performance for high-gradient dosimetry was evaluated. The Nikon scanner demonstrated a high sensitivity for radiochromic film dosimetry, resulting in more contrast in the digitized image. The scanner's optics also demonstrated excellent stability and did not necessitate warm-up scans prior to data acquisition. Moreover, negative effects of temperature changes of the film inside the scanner were shown to be limited. None of the digitized images showed significant disturbances by moiré-patterns, by virtue of the absence of a glass plate for film positioning. However, scanner response was found to vary considerably across the reading area, requiring an optical density-dependent correction procedure to be incorporated into the scanning protocol. The main limitation of the Nikon Coolscan 9000 ED transmission scanner remains its film size restriction to 6.2 × 20 cm2. Nevertheless, its excellent characteristics render it the preferential tool for high-gradient radiochromic film dosimetry in applications limited to small film sizes, such as dosimetry in the build-up region. PMID:22127288

De Puysseleyr, A; Srivastava, R P; Paelinck, L; De Neve, W; De Wagter, C

2012-01-01

304

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

PubMed

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

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

2013-07-01

305

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

PubMed

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

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

2014-09-15

306

A novel smart microsphere with magnetic core and ion-recognizable shell for pb(2+) adsorption and separation.  

PubMed

Smart core-shell microspheres for selective Pb(2+) adsorption and separation have been developed. Each microsphere is composed of a Pb(2+) recognizable poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNB) shell and a magnetic Fe3O4 core. The magnetic PNB core-shell microspheres show excellent Pb(2+) adsorption selectivity among the coexisting Cd(2+), Co(2+), Cr(3+), Cu(2+), Ni(2+), Zn(2+), K(+), and Ca(2+) ions by forming stable B18C6Am/Pb(2+) host-guest complexes and exhibit an interesting temperature-dependent Pb(2+) adsorption. The inner independent magnetic Fe3O4 cores enable the Pb(2+)-adsorbed microspheres with a magnetically guided aggregation to be separated from the treated solution using a remotely controlled manner. The isothermal Pb(2+) adsorption result fits well with the Freundlich isotherm. The magnetic PNB core-shell microspheres show very fast adsorption of Pb(2+), and the adsorption process of Pb(2+) onto magnetic PNB core-shell microspheres fits well with the pseudo-second-order model. Moreover, Pb(2+)-adsorbed microspheres can be regenerated by simply increasing the operation temperature and washing with deionized water. The proposed magnetic PNB core-shell microspheres provide a promising candidate for Pb(2+) adsorbents with selectively separable and efficiently reusable abilities. PMID:24897191

Liu, Ying-Mei; Ju, Xiao-Jie; Xin, Yan; Zheng, Wei-Chao; Wang, Wei; Wei, Jie; Xie, Rui; Liu, Zhuang; Chu, Liang-Yin

2014-06-25

307

Fermi surface reconstruction by dynamic magnetic fluctuations and spin-charge separation near an O(3) quantum critical point  

NASA Astrophysics Data System (ADS)

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 physically interesting regime there is a magnetically driven Lifshitz point (LP) inside the magnetically disordered phase. At the LP the topology of the hole Fermi surface is changed. The position of the LP, while being close to the position of the QCP, generally differs. Dependent on the additional hole hopping integrals t' and t'', the LP can be located in the magnetically ordered phase and/or in the magnetically disordered phase. We also demonstrate that in this regime the hole spin and charge necessarily separate when approaching the QCP. The considered model sheds light on generic problems concerning the physics of the cuprates.

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

2013-02-01

308

Coal preparation using magnetic separation. Volume 4. Evaluation of magnetic fluids for coal benefication. Final report. [Magnetic fluids are defined as dispersant-stabilized suspensions of ferromagnetic or ferrimagnetic particles in a carrier fluid  

Microsoft Academic Search

Research objectives were to acquire a body of information on the properties and potential applications of magnetic fluids, to study the selective coating behavior of magnetic fluids when contacted with a mixture of organic an inorganic matter, and to determine the extent of coal beneficiation that can be acccomplished with fluid-enhanced magnetic separation. Objectives were achieved by performing an extensive

T. A. Sladek; C. H. Cox

1980-01-01

309

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

310

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

PubMed

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

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

2007-04-15

311

Aggregation and dispersion methods of magnetic particles, separation and detection methods using the same and detection kit  

US Patent & Trademark Office Database

It is intended to provide a method capable of simply aggregating magnetic particles having a surface modified with a thermoresponsive polymer at a given temperature without heating or cooling an aqueous solution containing the magnetic particles, and a separation method and a detection method of a substance to be detected in a sample using the method. The method of separating a substance to be detected from a sample includes the steps of: mixing an adsorbent and the sample in an aqueous solution to adsorb the substance to be detected on the adsorbent, aggregating the adsorbent by changing a salt concentration in the aqueous solution; and collecting the adsorbent from the aqueous solution by a magnetic force, wherein said adsorbent comprises a magnetic particle of an average particle size of 50 to 1000 nm, a surface of which is modified with a thermoresponsive polymer and is immobilized with a substance having an affinity for the substance to be detected.

2012-01-31

312

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

Microsoft Academic Search

Magnetic molecularly imprinted polymers were prepared using hydrophobic Fe3O4 magnetite as the magnetically susceptible component, oxytetracycline as template molecule, methacrylic acid as functional monomer, and styrene and divinylbenzene as polymeric matrix components. The polymers were applied to the separation of tetracycline antibiotics from egg and tissue samples. The extraction and clean-up procedures were carried out in a single step by

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

2009-01-01

313

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

Microsoft Academic Search

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

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

2008-01-01

314

Magnetic cell separation for purification of human oral keratinocytes: an effective method for functional studies without prior cell subcultivation  

Microsoft Academic Search

In studying human oral keratinocytes, it would be very helpful to obtain a pure population of cells without prior in vitro\\u000a expansion. An immunomagnetic separation technique, or magnetic cell separation (MACS), was modified for efficient purification\\u000a of human oral keratinocytes. Subsequent to two-step enzymatic digestion, the cell suspension was labelled with a mouse anti-CD45\\u000a (pan-leukocyte) monoclonal antibody (MoAb) to stain

M. Formanek; A. Temmel; B. Knerer; M. Willheim; W. Millesi; J. Kornfehl

1998-01-01

315

Excitonic charge-density-wave instability of spatially separated electron-hole layers in strong magnetic fields  

Microsoft Academic Search

We use the Hartree-Fock approximation to investigate the ground state of a system consisting of spatially separated electron and hole layers in strong magnetic fields. When the layer separation is larger than a critical value a novel excitonic-density-wave state is found to have a lower energy than either a homogeneous exciton fluid or a double charge-density-wave state. The order parameters

X. M. Chen; J. J. Quinn

1991-01-01

316

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

NASA Astrophysics Data System (ADS)

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

Harrison, Neil

2010-03-01

317

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

PubMed Central

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

2013-01-01

318

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

PubMed

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

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

2014-09-15

319

Multi-MW K-Band Harmonic Multiplier: RF Source For High-Gradient Accelerator R and D  

SciTech Connect

A preliminary design is presented for a two-cavity harmonic multiplier, intended as a high-power RF source for use in experiments aimed at developing high-gradient structures for a future collider. The harmonic multiplier is to produce power at selected frequencies in K-band (18-26.5 GHz) using as an RF driver an XK-5 S-band klystron (2.856 GHz). The device is to be built with a TE{sub 111} rotating mode input cavity and interchangeable output cavities running in the TE{sub n11} rotating mode, with n = 7,8,9 at 19.992, 22.848, and 25.704 GHz. An example for a 7{sup th} harmonic multiplier is described, using a 250 kV, 20 A injected laminar electron beam; with 10 MW of S-band drive power, 4.7 MW of 20-GHz output power is predicted. Details are described of the magnetic circuit, cavities, and output coupler.

Solyak, N. A.; Yakovlev, V. P. [Omega-P, Inc., 199 Whitney Ave., New Haven, CT 06511 (United States); Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kazakov, S. Yu. [Omega-P, Inc., 199 Whitney Ave., New Haven, CT 06511 (United States); High Energy Accelerator Research Organization, KEK, Tsukuba, Ibaraki 305-0801 Japan (Japan); Hirshfield, J. L. [Omega-P, Inc., 199 Whitney Ave., New Haven, CT 06511 (United States); Beam Physics Laboratory, Yale University, 272 Whitney Avenue, New Haven, CT 06511 (United States)

2009-01-22

320

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

EPA Science Inventory

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

321

Separable nonlinear least squares fitting with linear bound constraints and its application in magnetic resonance spectroscopy data quantification  

Microsoft Academic Search

An application in magnetic resonance spectroscopy quantification models a signal as a linear combination of nonlinear functions. It leads to a separable nonlinear least squares fitting problem, with linear bound constraints on some variables. The variable projection (VARPRO) technique can be applied to this problem, but needs to be adapted in several respects. If only the nonlinear variables are subject

Diana M. Sima; Sabine Van Huffel

2007-01-01

322

Utility of Magnetic Cell Separation as a Molecular Sperm Preparation Technique  

PubMed Central

Assisted reproductive techniques (ART) have become the treatment of choice in many cases of infertility; however the current success rates of these procedures remain suboptimal. Programmed cell death (apoptosis) most likely contributes to failed ART and to the decrease in sperm quality after cryopreservation. There is likelihood that some sperm selected for ART will display features of apoptosis despite their normal appearance, which may be partially responsible for the low fertilization and implantation rates seen with ART. One of the features of apoptosis is the externalization of phosphatidylserine (PS) residues, which are normally present on the inner leaflet of the sperm plasma membrane. Colloidal super-paramagnetic microbeads (~50 nm in diameter) conjugated with annexin-V bind to PS are used to separate dead and apoptotic spermatozoa by magnetic cell sorting (MACS). Cells with externalized PS will bind to these microbeads, while non-apoptotic cells with intact membranes do not bind and could be used during ART. We have conducted a series of experiments to investigate if the MACS technology could be used to improve ART outcomes. Our results clearly indicate that integrating MACS as a part of sperm preparation techniques will improve semen quality and cryosurvival rates by eliminating apoptotic sperm. Non-apoptotic spermatozoa prepared by MACS display higher quality in terms of routine sperm parameters and apoptosis markers. The higher sperm quality is represented by an increased oocyte penetration potential and cryosurvival rates. Thus, the selection of non-apoptotic spermatozoa by MACS should be considered to enhance ART success rates.

Said, Tamer M.; Agarwal, Ashok; Zborowski, Maciej; Grunewald, Sonja; Glander, Hans-Juergen; Paasch, Uwe

2009-01-01

323

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

NASA Astrophysics Data System (ADS)

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

Mayo, John Thomas

324

Magnetic separation: track-etched magnetic micropores for immunomagnetic isolation of pathogens (adv. Healthcare mater. 7/2014).  

PubMed

On page 1078, D. Issadore and colleagues develop a new approach for isolating pathogens from messy clinical samples. Their platform, Track Etched Magnetic MicropOre (TEMPO), uses a microporous membrane coated with a soft magnetic film, creating enormous arrays of magnetic traps which allow the advantages of microfluidics to be preserved, but is robust against clogging and capable of extremely high flow rates. PMID:25044455

Muluneh, Melaku; Shang, Wu; Issadore, David

2014-07-01

325

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

326

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

Microsoft Academic Search

Magnetophoresis---the motion of magnetic particles under applied magnetic gradient---is a process of great interest in novel applications of magnetic nanoparticles and colloids. In general, there are two main different types of magnetophoresis processes: cooperative magnetophoresis (a fast process enhanced by particle-particle interactions) and noncooperative magnetophoresis (driven by the motion of individual particles in magnetic fields). In the case of noncooperative

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

2011-01-01

327

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

PubMed

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

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

2010-02-15

328

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

PubMed

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

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

2014-06-11

329

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

SciTech Connect

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

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

2012-07-03

330

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

SciTech Connect

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

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

2011-06-01

331

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

SciTech Connect

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

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

2005-08-02

332

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

SciTech Connect

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

Rosenzweig, J.B.; Hoover, S.; Thompson, M.; Travish, G.; Yoder, R. [UCLA Dept. of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Hogan, M.J. [Stanford Linear Accelerator Center, Stanford California 94309 (United States); Muggli, P. [University of Southern California, University Park Campus, Los Angeles, CA 90089 (United States)

2004-12-07

333

Ionization front accelerator: high gradients, demonstrated particle acceleration, and a proposed relativistic accelerator  

SciTech Connect

The Ionization Front Accelerator (IFA) is a collective ion accelerator for which high-gradient particle acceleration has now been demonstrated. In the IFA, the space charge field at the front of an intense relativistic electron beam is controlled by a laser and used to accelerate an ion bunch. Two complete IFA systems have been built (IFA-1 and IFA-2). Here we present initial IFA-2 ion results that demonstrate that ions have been accelerated with controlled accelerating fields of 33 MV/m over 30 cm. Space charge fields of accelerators like the IFA and the plasma beat wave accelerator are compared, and both are shown to be capable of producing fields 1 GV/m and higher. The IFA systems are discussed and initial IFA-2 ion results are presented. Lastly, a relativistic IFA is proposed that should in principle, permit the attainment of virtually unlimited ion energies. 11 references, 8 figures.

Olson, C.L.; Frost, C.A.; Patterson, E.L.; Anthes, J.P.; Poukey, J.W.

1985-01-01

334

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

SciTech Connect

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

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

1997-07-01

335

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

SciTech Connect

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

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

2011-09-01

336

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

SciTech Connect

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

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

2012-07-03

337

A new furnace for high gradient directional growth. [solidification of in-situ composites  

NASA Technical Reports Server (NTRS)

A new design furnace for high gradient solidification of in-situ composites is presented. Its essential feature is the direct addition of heat to one side of a thin, pancake-like layer of liquid, and continuous withdrawal of a solid crystal from the other side. Liquid in the thin layer is continuously replenished by solid or liquid feed, and the thinness of the layer permits a large heat throughput with a high temperature gradient without excessive metal superheat. The commercial advantages of this design are improved process efficiency in scale-up, lower melt temperatures, and control of interface morphology by adjusting heater position and temperature. The furnace was tested on Sn-Pb and Al-Cu alloys, obtaining 100C/mm gradients for 6 mm specimens of Al-31.5 % Cu alloy.

Flemings, M. C.; Lee, D. S.; Neff, M. A.; Young, K. P.; Rickinson, B. A.

1979-01-01

338

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

SciTech Connect

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

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

2013-06-03

339

Synthesis of orientedly bioconjugated core\\/shell Fe 3O 4@Au magnetic nanoparticles for cell separation  

Microsoft Academic Search

Orientedly bioconjugated core\\/shell Fe3O4@Au magnetic nanoparticles were synthesized for cell separation. The Fe3O4@Au magnetic nanoparticles were synthesized by reducing HAuCl4 on the surfaces of Fe3O4 nanoparticles, which were further characterized in detail by TEM, XRD and UV–vis spectra. Anti-CD3 monoclonal antibody was orientedly bioconjugated to the surface of Fe3O4@Au nanoparticles through affinity binding between the Fc portion of the antibody

Yi-Ran Cui; Chao Hong; Ying-Lin Zhou; Yue Li; Xiao-Ming Gao; Xin-Xiang Zhang

340

Particle segregation in suspensions subject to high-gradient ac electric fields  

NASA Astrophysics Data System (ADS)

An experimental and theoretical study is described dealing with the dielectrophoretic motion of individual particles in a static as well as in a flowing suspension subject to high-gradient ac electric fields. The experiments were performed on very dilute suspensions of neutrally buoyant hollow ceramic spheres in a specially designed device in which the electric-field lines and the dielectrophoretic force were along the plane perpendicular to the streamlines of the main flow. Upon application of a high-gradient field (~several kV/mm) to a quiescent suspension, the particles were found to move away from the electrodes and then to concentrate above the grounded electrodes, forming a distinct boundary between the clean fluid and the remaining suspension. This same field, when applied to a flowing suspension, caused the particles to concentrate within thin stripes parallel to the flow above the grounded electrodes and to travel with the suspending fluid within these stripes. The theoretical model for the particle motion included only the dielectrophoretic force and the viscous drag, and required no fitting parameters because the particle polarizability was calculated independently by measuring the concentration dependence of the complex permittivity of the suspension in a spatially uniform electric field of low strength (~several V/mm). The computed particle motions and pattern formations were found to be in a good agreement with the experimental data. These results demonstrate that the expression for the dielectrophoretic force which employs the value of the particle polarization measured in fields of low strength can be used for describing the particle motions in fields of high strength. This approach enables one to model a broad range of electro-hydrodynamic phenomena in suspensions irrespective of whether or not they are perfectly insulating or perfectly conducting.

Dussaud, Anne D.; Khusid, Boris; Acrivos, Andreas

2000-11-01

341

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

PubMed

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

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

2011-08-01

342

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

343

Cell separation by antibody-coupled magnetic microspheres and their application in conjunction with monoclonal HLA-antibodies  

Microsoft Academic Search

The modification and efficiency of a technique for cell separation is described. This technique combines the specificity of serologic reactions with the strength and physical selectivity of a magnetic field. A monoclonal HLA-BW6 antibody was coupled to 400 nm diameter Fe3O4 containing albumin microspheres via surface-incorporated St. aureus Protein-A. The mixture of HLA-BW6 and-BW4 human peripheral blood lymphocytes was incubated

J. Kandzia; M. J. D. Anderson; W. Miiller-Ruchholtz

1981-01-01

344

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

PubMed

Phage display was performed against human IgG (hIgG) through five rounds of 'biopanning'. Each round consisted of: (1) incubating a library of phage-displayed 12-mer peptides sequences on hIgG-coated magnetic beads, (2) washing the unbound phages, and (3) eluting the bound phages. The eluted phages were either amplified to enrich the pool of positive clones or subjected to the next round without amplification. Through ELISA, four clones (F9, D1, G5, and A10) showing specific binding affinity to hIgG were identified. Among these, F9 had the highest affinity (K(d)=6.2 nM), only one order of magnitude lower than the native anti-hIgG antibody (0.66 nM). Following the DNA sequences of the selected clones, four 12-mer peptides were chemically synthesized. Among them, D1 peptide showed the highest binding affinity to hIgG via SPR biosensor measurements. This peptide was conjugated to biofunctionalized magnetic beads, and its immuno-binding ability was compared with that of the native antibody immobilized to magnetic beads. The mol-to-mol binding efficacy of the peptide-coated magnetic beads was approximately 1000-fold lower than that of the antibody-coated magnetic beads. Our results suggest a feasibility of using antibody-mimicking peptides identified by phage display technique for immuno-magnetic separation of an antigen. PMID:22796092

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

2012-10-31

345

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

NASA Astrophysics Data System (ADS)

We have performed electrical resistivity and DC magnetization measurements as a function of temperature, on polycrystalline samples of phase-separated La 5/8-yPr yCa 3/8MnO 3 ( y=0.3). We have used the general effective medium theory to obtain theoretical resistivity vs. temperature curves corresponding to different fixed ferromagnetic (FM) volume fraction values, assuming that the sample is a mixture of typical metallic-like and insulating manganites. By comparing this data with our experimental resistivity curves we have obtained the relative FM volume fraction of our sample as a function of temperature. This result matches with the corresponding magnetization data in excellent agreement, showing that a mixed-phase scenario is the key element to explain both the magnetic and transport properties in the present compound.

Sacanell, J.; Quintero, M.; Parisi, F.; Ghivelder, L.; Leyva, A. G.; Levy, P.

2007-09-01

346

Linear expansion, phase separation, and magnetic inhomogeneities in La0.92Ca0.08MnO3  

NASA Astrophysics Data System (ADS)

A relation of the thermal expansion with magnetic and magnetotransport properties has been revealed in La0.92Ca0.08MnO3 single crystals in the paramagnetic state. The magnetotransport and lattice properties and the specific features in the neutron scattering characteristics of the La0.92Ca0.08MnO3 single crystals have been explained by the phase separation in the paramagnetic state into magnetic inhomogeneities (clusters) with short-range (˜10 Å) and long-range (>102 Å) orders. The performed investigations have demonstrated that the clusters are closely related to the crystal lattice and that the magnetic inhomogeneities in the paramagnetic region are correlated to T ˜ 250-300 K ? TC.

Solin, N. I.; Kazantsev, V. A.

2013-09-01

347

Correspondence between neutron depolarization and higher order magnetic susceptibility to investigate ferromagnetic clusters in phase separated systems  

NASA Astrophysics Data System (ADS)

It is a tough task to distinguish a short-range ferromagnetically correlated cluster-glass phase from a canonical spin-glass-like phase in many magnetic oxide systems using conventional magnetometry measurements. As a case study, we investigate the magnetic ground state of La0.85Sr0.15CoO3, which is often debated based on phase separation issues. We report the results of two samples of La0.85Sr0.15CoO3 (S-1 and S-2) prepared under different conditions. Neutron depolarization, higher harmonic ac susceptibility and magnetic relaxation studies were carried out along with conventional magnetometry measurements to differentiate subtle changes at the microscopic level. There is no evidence of ferromagnetic correlation in the sample S-2 attributed to a spin-glass phase, and this is compounded by the lack of existence of a second order component of higher harmonic ac susceptibility and neutron depolarization. A magnetic relaxation experiment at different temperatures complements the spin glass characteristic in S-2. All these signal a sharp variance when we consider the cluster-glass-like phase (phase separated) in S-1, especially when prepared from an improper chemical synthesis process. This shows that the nonlinear ac susceptibility is a viable tool to detect ferromagnetic clusters such as those the neutron depolarization study can reveal.

Manna, Kaustuv; Samal, D.; Bera, A. K.; Elizabeth, Suja; Yusuf, S. M.; Kumar, P. S. Anil

2014-01-01

348

Correspondence between neutron depolarization and higher order magnetic susceptibility to investigate ferromagnetic clusters in phase separated systems.  

PubMed

It is a tough task to distinguish a short-range ferromagnetically correlated cluster-glass phase from a canonical spin-glass-like phase in many magnetic oxide systems using conventional magnetometry measurements. As a case study, we investigate the magnetic ground state of La0.85Sr0.15CoO3, which is often debated based on phase separation issues. We report the results of two samples of La0.85Sr0.15CoO3 (S-1 and S-2) prepared under different conditions. Neutron depolarization, higher harmonic ac susceptibility and magnetic relaxation studies were carried out along with conventional magnetometry measurements to differentiate subtle changes at the microscopic level. There is no evidence of ferromagnetic correlation in the sample S-2 attributed to a spin-glass phase, and this is compounded by the lack of existence of a second order component of higher harmonic ac susceptibility and neutron depolarization. A magnetic relaxation experiment at different temperatures complements the spin glass characteristic in S-2. All these signal a sharp variance when we consider the cluster-glass-like phase (phase separated) in S-1, especially when prepared from an improper chemical synthesis process. This shows that the nonlinear ac susceptibility is a viable tool to detect ferromagnetic clusters such as those the neutron depolarization study can reveal. PMID:24275331

Manna, Kaustuv; Samal, D; Bera, A K; Elizabeth, Suja; Yusuf, S M; Kumar, P S Anil

2014-01-01

349

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

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

350

Magnetically separable and recyclable urchin-like Co-P hollow nanocomposites for catalytic hydrogen generation  

NASA Astrophysics Data System (ADS)

One-pot well-controlled synthetic strategy was developed to achieve urchin-like Co-P hollow nanocomposites with tailorable magnetic properties which enable them to perform as magnetically recyclable nanocatalysts in a “quasi-homogeneous” system for the catalytic hydrogen generation via hydrolysis of Ammonia-Borane (AB). The key point of this strategy was that ferromagnetic Co nanoparticles (NPs) were embedded into paramagnetic Co2P matrix to form magnetic nanocomposites. The as-prepared Co-P NPs showed appreciable catalytic activity, recyclability and durability in hydrolysis of AB. Moreover, the chemical regeneration of AB from the “hydrolyzate” may also benefit from these magnetically recyclable catalysts. We further highlighted the excellent high-temperature resistance of Co-P NPs by calcining them at 300 °C and 600 °C. Our research may facilitate the practical application of AB as a sustainable hydrogen storage material for hydrogen-based energy.

Guo, Huizhang; Liu, Xiang; Hou, Yuhui; Xie, QingShui; Wang, Laisen; Geng, Hao; Peng, Dong-Liang

351

Meniscus-Assisted High-Efficiency Magnetic Collection and Separation for EWOD Droplet Microfluidics  

Microsoft Academic Search

This paper describes a technique to increase the efficiency of magnetic concentration on an electrowetting-on-dielectric (EWOD)-based droplet (digital) microfluidic platform operated in air, i.e., on dry surface. Key differences in the force scenario for droplet microfluidics vis-a-vis the conventional continuous microfluidic systems are identified to explain the rationale behind the proposed idea. In particular, the weakness of the magnetic force

Gaurav J. Shah

2009-01-01

352

Separation of the contributions to the magnetization of Tm1 - x Yb x B12 solid solutions in steady and pulsed magnetic fields  

NASA Astrophysics Data System (ADS)

The magnetization of substitutional Tm1 - x Yb x B12 solid solutions is studied in the composition range 0 < x ? 0.81. The measurements are performed at low temperatures (1.9-300 K) in steady (up to 11 T) and pulsed (up to 50 T, pulse duration of 20-100 ms) magnetic fields. An analysis of the experimental data allowed the contributions to the magnetization of the paramagnetic phase of the Tm1 - x Yb x B12 compounds to be separated. These contributions include a Pauli component, which corresponds to the response of the heavy-fermion manybody states that appears in the energy gap in the vicinity of the Fermi level (density of states (3-4) × 1021 cm-3 meV-1), and a contribution with saturation in high magnetic fields attributed to the localized magnetic moments ((0.8-3.7)?B per unit cell) of the nanoclusters formed by rare-earth ions with an antiferromagnetic interaction.

Bogach, A. V.; Sluchanko, N. E.; Glushkov, V. V.; Demishev, S. V.; Azarevich, A. N.; Filippov, V. B.; Shitsevalova, N. Yu.; Levchenko, A. V.; Vanacken, J.; Moshchalkov, V. V.; Gabani, S.; Flachbart, K.

2013-05-01

353

Multi-Compartment Separation in Magnetic Resonance Using Transient Steady-State Free Precession Imaging.  

National Technical Information Service (NTIS)

Disclosed is a method of quantitatively separating tissue signals based on relaxation time differences. The method uses the transient signal decay in steady-state free precession (balanced SSFP) imaging to provide an alternative to standard CPMG methods o...

B. A. Hargreaves

2003-01-01

354

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

SciTech Connect

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

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

2008-02-06

355

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

SciTech Connect

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

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

2005-05-17

356

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

NASA Astrophysics Data System (ADS)

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

Fazio, Michael V.; Anderson, Scott G.

2012-12-01

357

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

SciTech Connect

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

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

2006-01-25

358

Dynamic Z-pinches for high-gradient, high-current acceleration  

NASA Astrophysics Data System (ADS)

In this talk, we discuss planned experiments on acceleration of an injected ion beam in a Z-pinch plasma with MV/cm gradients and the first fully kinetic simulations of such beam-plasma systems. Multi-MeV, kilo-Ampere ion beams have been produced by 100 kJ class, centimeter scale, Dense Plasma Focus (DPF) Z-pinches. We have now demonstrated similar acceleration gradients in a 1 kJ DPF using a fast capacitive driver. Understanding the mechanisms behind these high gradients is essential for optimizing the device for unique compact accelerator applications. We have an RFQ accelerator producing a 4 MeV deuteron beam for probing the DPF plasma. Using this beam we can directly measure the gradients and demonstrate acceleration of an injected ion beam for the first time. Our fully kinetic particle-in-cell simulations have reproduced observed DPF ion beams. Direct comparisons between the experiment and simulations enhance our understanding of these plasmas and provide predictive design capability. These are the first steps to enabling a technologically simple, compact, high-current, plasma-based accelerator.

Tang, V.; Schmidt, A.; Ellsworth, J.; Falabella, S.; Rusnak, B.; Guethlein, G.; Akana, G.; Cook, E.; Hawkins, S.; Welch, D.

2012-10-01

359

High-gradient experiment on X-band disk-loaded structures  

NASA Astrophysics Data System (ADS)

The high-gradient performance of two travelling-wave X-band accelerating structures 20 cm long has been studied. One of the structures, KEK, was conditioned up to an average accelerating gradient (Eav) of 68 MV/m in 600 hours, while the other, CERN, reached 85 MV/m in 50 hours. In the latter case the maximum output power was fed from the SLED system and the maximum field inside the structure was 138 MV/m. This maximum level was limited by the available power from the klystron. Operation at the Eav=50 MV/m level was found to be stable for both structures. The associated dark current at this level was less than a few (mu)A for CERN but 20 to 30 (mu)A for KEK. Since the two electrical designs are almost the same the difference in dark current must be attributed to the difference in the two fabrication techniques. Modified Fowler-Northeim plots of downstream dark current showed a change of slope, a kink, around 50 to 60 MV/m above which the field enhancement factor was substantially increased.

Higo, T.; Taniuchi, T.; Yamamoto, M.; Odagiri, J.; Tokumoto, S.; Mizuno, H.; Takata, K.; Wilson, I.; Wuensch, W.

1993-09-01

360

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

Microsoft Academic Search

The techniques of recoil-gating and recoil-decay tagging have been employed at Jyväskylä to perform in-beam ?-ray and electron spectroscopy studies of heavy nuclei. The JUROSPHERE ?-ray array and the SACRED electron spectrometer have been placed at the target position of the JYFL gas-filled recoil separator recoil ion transport unit (RITU). The RITU separator has been used to collect the recoils

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

2003-01-01

361

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

PubMed

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

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

2013-11-01

362

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

PubMed

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

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

2009-05-01

363

Inactivation and magnetic separation of bacteria from liquid suspensions using electrosprayed and nonelectrosprayed nZVI particles: observations and mechanisms.  

PubMed

Here, nonelectrosprayed nanoscale zerovalent iron (NE-nZVI), electrosprayed nZVI (E-nZVI) and preoxidized nZVI (O-nZVI) particles were applied to inactivating Bacillus subtilis, Escherichia coli as well as bacteria in various wastewater samples. In addition, magnetic separation was applied to the mixture of 0.2 mL bacterial sample and 1.8 mL E-nZVI or NE-nZVI suspensions. Bacterial concentrations and optical density of the supernatants were analyzed using culturing, optical adsorption and qPCR tests. In general, for wastewater samples the inactivations were shown to range from 1-log to 3-log. PCR-DGGE analysis indicated that no gene mutation occurred when bacteria were treated with nZVI. Using magnetic separation, significant physical removals, revealed as a function of nZVI type (NE-,E- and O-nZVI) and bacterial concentration, up to 6-log were obtained. E-nZVI and NE-nZVI were shown to react differently with B. subtilis and E. coli, although exhibiting similar inactivation rates. qPCR tests detected higher amount of DNA in the supernatants from mixing E. coli with NE-nZVI, but less for E-nZVI. However, the opposite was observed with B. subtilis. Our data together with optical adsorption analysis suggested that the inactivation and magnetic separation mainly depend on Fe(0)/Fe(3)O(4) shell compositions, the type of bacteria (aerobic and anaerobic) and their concentrations. PMID:22264123

Chen, Qi; Gao, Min; Li, Jing; Shen, Fangxia; Wu, Yan; Xu, Zhenqiang; Yao, Maosheng

2012-02-21

364

Water-compatible magnetic imprinted microspheres for rapid separation and determination of triazine herbicides in environmental water.  

PubMed

A novel kind of water-compatible magnetic imprinted cyromazine microsphere (WCMM) was synthesized by water/oil/water suspension polymerization. The obtained WCMM was homogenously spherical with porous morphology and strong magnetic properties. The microspheres were successfully used as adsorbent in dispersive solid-phase extraction (WCMM-dSPE) to selectively extract cyanazine and atrazine from environmental water. Good linearity of the two analytes was observed in the range from 2.5 to 200.0ngmL(-1). The average recoveries at three spiking levels ranged from 84.8% to 104.3% with relative standard deviations (RSD) less than 6.9%. Compared with magnetic non-imprinted particles (WCMN), the proposed WCMM adsorbent of dSPE efficiently improved the efficiency of extracting cyanazine and atrazine from environmental water samples and eliminated the effect of cyromazine leakage on the quantitative analysis of cyanazine and atrazine. The proposed WCMM-dSPE method combined the advantages of magnetic separation, molecular imprinted microspheres and dSPE. PMID:24657415

Qiao, Fengxia; Row, Kyung Ho; Wang, Mengge

2014-04-15

365

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

NASA Astrophysics Data System (ADS)

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

366

Photocatalytic degradation of methylene blue by magnetically separable BiVO4 supported on Fe3O4 nanoparticles  

Microsoft Academic Search

Non-titania photocatalyst BiVO4 was supported on SiO2-coated Fe3O4 particles in order to solve the problems of photocatalyst recovery and reuse. The prepared photocatalyst BiVO4\\/SiO2\\/Fe3O4 (BiVO4\\/SFN) was proved to be nano-sized (less than 10 nm) by TEM characterization. The superparamagnetism of BiVO4\\/SFN was confirmed by a vibrating sample magnetometer (VSM). The photocatalyst can be easily separated experimentally by an external magnetic

Guoting Li; Gangfu Song; Jing Chen; Meiya Zhu; P. K. Wong

2010-01-01

367

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

Microsoft Academic Search

The separate structure of two branches of the sheared slab etai mode near the minimum-q magnetic surface is analysed and the effects of plasma rotation shears are considered in the weak magnetic shear region. Results show that the separation condition depends on the non-monotonous q profile and the deviation of rational surface from the minimum-q surface. Furthermore, it is found

Jiquan Li; Y. Kishimoto; T. Tuda

2000-01-01

368

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

SciTech Connect

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

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

2013-01-01

369

Negative dielectrophoresis and segregation in concentrated suspensions in high-gradient AC electric fields  

NASA Astrophysics Data System (ADS)

Experiments were conducted on concentrated suspensions of neutrally buoyant polyolefin spheres dispersed in oil which exhibited negative dielectrophoresis. Following the application of a high-gradient AC field of several kV/mm, most of the particles were found to move away from the electrodes and then to concentrate in the area of a low electric field located above the grounded electrodes, forming a distinct boundary between the clean fluid and the suspension. The proposed mathematical model for the field-induced particle segregation consists of strongly coupled field and flow equations with the suspension being viewed as an effective Newtonian fluid with a concentration-dependent viscosity. For the electric stress, we employed the constitutive equations corresponding to the extreme of strong electric energy dissipation of our microscopic theory. This theory employs the Lorentz model for the long-range electrical interactions of polarized particles. The equation for the total particle flux includes the flux induced by the electric force exerted on a particle due to the gradient of its chemical potential in a spatially non-uniform electric field. The hydrodynamic interactions of the particles are incorporated through the concentration dependence of the particle mobility and the hindrance function in the expression for the particle settling velocity relative to the suspending fluid. The proposed model does not require any fitting parameters provided that the particle polarizability is measured in low-strength filed of several V/mm. The computed kinetics of the particle segregation and pattern formation was found to be consistent with the experimental data. The work was supported by a NASA grant. The suspension characterization was conducted at the NJIT W.M. Keck Laboratory.

Khusid, Boris; Jacqmin, David; Qiu, Zhiyong; Acrivos, Andreas; Kumar, Anil

2002-11-01

370

Method of separating dipole magnetic anomaly from geomagnetic field and application in underwater vehicle localization  

Microsoft Academic Search

Because dipole magnetic anomaly caused by ferromagnetic object or geologic structural change is mixed with geomagnetic field and difficult to calculate its magnitude, it lead to a problem for automatic underwater vehicle (AUV) localization aided by geomagnetic anomaly. To solve this issue, a novel AUV localization method introducing draft depth is put forward, where vertical position of AUV relative to

Huang Yu; Hao Yan-ling

2010-01-01

371

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

NASA Astrophysics Data System (ADS)

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.

Tarr, Lucas; Longcope, Dana; Millhouse, Margaret

2013-06-01

372

Experience in using separators based on rare-earth permanent magnets to enrich nonmetalliferous materials  

Microsoft Academic Search

?rga NPF is the leading manufacturer of rare-earth permanent magnets and equipment based on them. When used for enriching\\u000a the initial materials for making glass such equipment sharply reduces the Fe2O3 content in the initial materials and thereby improves the quality of the manufactured glass articles.

S. V. Kotunov; A. V. Vlasko

2007-01-01

373

Quench performance of Fermilab high gradient quadrupole short models for the LHC Interaction Regions  

Microsoft Academic Search

Fermilab and LBNL are in the midst of superconducting magnet R&D program to test and optimize the design of quadrupoles to be used in the LHC Interaction Region inner triplets. The magnets are required to deliver a 215 T\\/m gradient across a 70 mm aperture. Five quadrupole short models have been fabricated and four of them have been tested. This

N. Andreev; T. Arkan; R. Bossert; J. Brandt; D. Chichili; J. DiMarco; S. Feher; J. Kerby; M. J. Lamm; P. J. Limon; F. Nobrega; D. Orris; I. Novitski; J. P. Ozelis; T. Peterson; G. Sabbi; P. Schlabach; J. Strait; M. Tartaglia; J. C. Tompkins; S. Yadav; A. V. Zlobin; S. Caspi; A. D. McInturff; R. M. Scanlan; A. Ghosh

1999-01-01

374

Magnetic flocculation and filtration  

SciTech Connect

A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.

Yiacoumi, Sotira; Chin, Ching-Ju; Yin, Tung-Yu [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering; Tsouris, C., DePaoli, D.W.; Chattin, M.R.; Spurrier, M. [Oak Ridge National Lab., TN (United States)

1996-10-01

375

The function of neutrophils isolated by a magnetic antibody cell separation technique is not altered in comparison to a density gradient centrifugation method  

Microsoft Academic Search

Most comparative studies on neutrophil (PMN) isolation techniques have shown either activation or functional impairment of the cells due to the different separation processes. We have established a preparation method for PMN from human whole blood employing iron tagged, magnetizable antibodies against the cell surface antigen CD15. The aim of our study was to test whether this magnetic separation (MACS)

Stefan Zahler; Christian Kowalski; Andreas Brosig; Christian Kupatt; Bernhard F. Becker; Eckehart Gerlach

1997-01-01

376

Mass separation of a multicomponent plasma flow in a curvilinear magnetic field  

SciTech Connect

The motion of a metal plasma flow of a vacuum-arc discharge in a transportation plasma-optical system with a curvilinear magnetic field is studied experimentally and numerically. The flow position at the output of the system is shown to depend on the cathode material, which determines the mass-to-charge ratio of plasma ions. As a result, the flow with a greater ion mass-to-charge ratio moves along a trajectory with a larger radius. A similar effect is observed in the case of a multicomponent plasma flow generated by a composite cathode. The results of two-fluid MHD simulations of a plasma flow propagating in a curvilinear magnetic field agree qualitatively with the experimental data.

Papernyi, V. L.; Krasov, V. I. [Irkutsk State University (Russian Federation)

2011-11-15

377

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

Microsoft Academic Search

The Fermi surface topology of high temperature superconductors inferred from magnetic quantum oscillation measurements provides clues for the origin of unconventional pairing thus previously not accessed by other spectroscopy techniques. While the overdoped regime of the high Tc phase diagram has a large Fermi surface consistent with bandstructure calculations, the underdoped regime of YBa2Cu2O6+x is found to be composed of

Neil Harrison

2010-01-01

378

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

PubMed

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

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

2013-09-01

379

Screening of cyclodextrins by nuclear magnetic resonance for the design of chiral capillary electrophoresis separations  

Microsoft Academic Search

High-field one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy and capillary electrophoresis (CE) are examined to investigate the process of chiral recognition occurring between different cyclodextrins (CDs) and the racemic anti-schistosomiasis drug, oxamniquine. Five neutral CDs (?-CD, ?-CD, ?-CD, hydroxypropyl-?-CD and hydroxyethyl-?-CD) and two anionic CDs, carboxymethyl-?-CD (CM-?-CD) and sulphobutyl ether-?-CD (SBE-?-CD) were selected for these NMR and

Paul K Owens; Anthony F Fell; Michael W Coleman; John C Berridge

1998-01-01

380

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

Microsoft Academic Search

The projectile fragment separator FRS designed for research and applied studies with relativistic heavy ions was installed at GSI as a part of the new high-energy SIS\\/ESR accelerator facility. This high-resolution forward spectrometer has been successfully used in first atomic and nuclear physics experiments using neon, argon, krypton, xenon, and gold beams in the energy range from 500 to 2000

H. Geissel; P. Armbruster; K. H. Behr; A. Brünle; K. Burkard; M. Chen; H. Folger; B. Franczak; H. Keller; O. Klepper; B. Langenbeck; F. Nickel; E. Pfeng; M. Pfützner; E. Roeckl; K. Rykaczewski; I. Schall; D. Schardt; C. Scheidenberger; K.-H. Schmidt; A. Schröter; T. Schwab; K. Sümmerer; M. Weber; G. Münzenberg; T. Brohm; H.-G. Clerc; M. Fauerbach; J.-J. Gaimard; A. Grewe; E. Hanelt; B. Knödler; M. Steiner; B. Voss; J. Weckenmann; C. Ziegler; A. Magel; H. Wollnik; J. P. Dufour; Y. Fujita; D. J. Vieira; B. Sherrill

1992-01-01

381

Optimization of Yield in Magnetic Cell Separations Using Nickel Nanowires of Different Lengths  

Microsoft Academic Search

Ferromagnetic nanowires are shown to perform both high yield and high purity single- step cell separations on cultures of NIH-3T3 mouse fibroblast cells. The nanowires are made by electrochemical deposition in nanoporous templates, permitting detailed control of their chemical and physical properties. When added to fibroblast cell cultures, the nanowires are internalized by the cells via the integrin-mediated adhesion pathway.

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

2005-01-01

382

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

PubMed

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

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

2014-09-15

383

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

PubMed

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

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

2014-06-25

384

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

PubMed

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

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

2014-06-25

385

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

SciTech Connect

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

Iwamae, A.; Atake, M.; Sakaue, A.; Katai, R.; Goto, M.; Morita, S. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto, 606-8501 (Japan); Department of Fusion Science, Graduate University for Advanced Studies, Toki, 509-5292 (Japan); National Institute for Fusion Science, Toki, 509-5292 (Japan)

2007-04-15

386

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

PubMed

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

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

2013-06-15

387

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

SciTech Connect

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

Silver, G.L.

1980-07-31

388

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

PubMed Central

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 (qHNMR) methodology, partition coefficients (K) of individual terpene lactones were calculated directly from crude G. biloba leaf extract, using their H-12 signals as distinguishing feature. The partitioning experiment assisted the design of a two dimensional (2D) HSCCC procedure using a pair of orthogonal HSCCC solvent systems (SSs), ChMWat +4 and HEMSoWat +3/0.05%. It was surprising that the resolution of ginkgolides A and B was improved by 25% in the HEMWat +3 SS modified with 0.5% DMSO. Consequently, all five terpene lactones could be well separated with qHNMR purity > 95% from G. biloba leaf extract. The separation was further evaluated by offline qHNMR analysis of HSCCC fractions associated with Gaussian curve fitting. The results showed less than 2% error in HSCCC retention predicted from the partitioning experiment. This compelling consistency demonstrates that qHNMR-derived K determination (“K-by-NMR”) can be used to predict CCC fractionation and target purification of analytes from complex mixtures. Furthermore, Gaussian curve fitting enabled an accurate prediction of less than 2% impurity in the CCC fraction, which demonstrates its potential as a powerful tool to study the presence of minor constituents, especially when they are beyond the detection limit of conventional spectroscopic detectors.

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

2012-01-01

389

A high gradient superconducting quadrupole for a low charge state ion linac  

SciTech Connect

A superconducting quadrupole magnet has been designed for use as the focusing element in a low charge state linac proposed at Argonne. The expected field gradient is 350 T/m at an operating current of 53 A, and the bore diameter is 3 cm. The use of rare earth material holmium for pole tips provides about 10% more gradient then iron pole tips. The design and the status of construction of a prototype singlet magnet is described.

Kim, J.W.; Shepard, K.W.; Nolen, J.A.

1995-07-01

390

Phase-separated alloys for bulk exchange-biased permanent magnets  

SciTech Connect

Explorations in the metallurgical synthesis from the melt of bulk permanent magnets with coercivity conferred by the exchange bias mechanism were carried out in a two-phase materials system composed of ferromagnetic FeCo and antiferromagnetic, nominally equiatomic AuMn. Rapid solidification synthesis of composite alloys of nominal composition (Fe{sub 65}Co{sub 35}){sub 100-x}(AuMn){sub x} (x=5, 10, and 15) was carried out. The ribbons possess AuMn and Au{sub 2}Mn spherical phases in a bcc (Fe,Co) matrix with a bimodal size distribution of nanoscaled and micron sizes. Magnetization measurements of the composite confirm an exchange bias effect correlated with a coercivity increase over that of the (Fe,Co) melt-spun base alloy. While the exchange bias effect is small, the enhanced coercivity and shifted hysteresis loop observed in a single sample create a strong argument for coercivity enhancement conferred by the exchange bias interaction between antiferromagnetic and ferromagnetic phases in a bulk melt-spun nanocomposite material.

Lewis, L. H.; Harland, C. L.; McCallum, R. W.; Kramer, M. J.; Dennis, K. W. [Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Ames Laboratory, Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2006-04-15

391

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

NASA Astrophysics Data System (ADS)

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

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

2006-09-01

392

Phase-separated alloys for bulk exchange-biased permanent magnets  

NASA Astrophysics Data System (ADS)

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

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

2006-04-01

393

Complex magnetic phase separation induced by Li-doping in multiferroic CaBaCo4O7  

NASA Astrophysics Data System (ADS)

The doping of lithium at the cobalt sites in the multiferroic orthorhombic cobaltite CaBaCo4O7 has been investigated. The oxides CaBaCo4-2xLixGaxO7 and CaBaCo4-xLixO7 keep the same polar space group as the parent phase. In contrast, they show a spectacular decrease of their ferrimagnetic properties for very low doping levels (0 < x <= 0.10), with the appearance of antiferromagnetism below TN ~ 80 K and magnetic frustration at around Tf ~ 20 K, which should have a great impact upon multiferroism in this system. This behavior is different from that of the Ga-doped phases CaBaCo4-xGaxO7, but remarkably similar to that of the Zn-doped phases CaBaCo4-xZnxO7. The actual role of the valence of the diamagnetic cation, Li+ is interpreted from its ability to sit in the Co2+ zig-zag chain, breaking the ferromagnetism along those chains in both series of oxides. Importantly, the Li-doping in CaBaCo4-xLixO7 oxides, introduces an excess Co3+ with respect to the other two series, CaBaCo4-xZnxO7 and CaBaCo4-2xLixGaxO7. This additional Co3+ is thought to be at the origin of the complex magnetic phase separation and especially of new magnetic interactions that appear around 52 K in competition with magnetic frustration and antiferromagnetism.

Motin Seikh, Md.; Sarkar, Tapati; Pralong, V.; Caignaert, V.; Raveau, B.

2013-02-01

394

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

PubMed

A facile co-gelation route has been developed to synthesize novel porous Fe(7)Co(3)/carbon composites with Fe(7)Co(3) nanoparticles embedded in the porous carbon matrix. The sol-gel process of this route simultaneously involves the hydrolysis of tetraethylorthosilicate (TEOS) and the polymerization of furfuryl alcohol (FA) within an ethanol solution containing TEOS, FA, and metal nitrates, which led to the inorganic/organic hybrid xerogel, accompanying metal salts spontaneously captured in the xerogel, mostly in the framework of poly(furfuryl alcohol) (PFA). Compared to the nanocasting route, the advantage of this method is that the formation of silica template and the impregnation of carbon precursor and metal salts were simultaneously carried out in one co-gelation process, which makes the synthesis very simple and eliminates the time-consuming synthesis of the silica template and multistep impregnation process. Different amounts of Fe(7)Co(3) can be introduced into the composites, which led to different pore structures and magnetic properties. The composites have large surface areas (as high as 651.4 m(2)/g) and high saturation magnetizations (as high as 31.2 emu/g). The Fe(7)Co(3)/carbon composites prepared were successfully applied to the removal of dyes from water and catalysis of hydrogenation as efficient magnetically separable adsober and catalyst support. The facile co-gelation route makes the scalable synthesis of magnetic porous carbon possible for application, and it also provides a promising path to the synthesis of nanoscale metal or alloy embedded in the porous carbon materials. PMID:20369845

Wang, Zhongli; Liu, Ruixia; Zhao, Fengyu; Liu, Xiaojuan; Lv, Minfeng; Meng, Jian

2010-06-15

395

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

NASA Astrophysics Data System (ADS)

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

Bali, G. S.; Bruckmann, F.; Endr?di, G.; Fodor, Z.; Katz, S. D.; Schäfer, A.

2014-04-01

396

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

NASA Astrophysics Data System (ADS)

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

Harrison, B. K.; Orphan, V.

2006-12-01

397

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

SciTech Connect

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

398

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

399

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

PubMed Central

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

2013-01-01

400

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

401

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

PubMed

The pressure dependence of the Curie temperature T(C)(P) in La(0.75)Ca(0.25)MnO(3) was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature T(IM)(P) (Postorino et al 2003 Phys. Rev. Lett. 91 175501). The behavior of the two temperatures appears similar over the whole pressure range, suggesting a key role of magnetic double-exchange also in the pressure regime where the superexchange interaction is dominant. The coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data. PMID:22214651

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

2012-02-01

402

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

403

Hybrid magnetic field formulation based on the losses separation method for modified dynamic inverse Jiles-Atherton model  

NASA Astrophysics Data System (ADS)

Dynamic formulation based on the losses separation method in conducting media for the inverse Jiles-Atherton model is proposed. This formulation is based on the concept of the Hybrid Magnetic Field model (HMF). The HMF consists of the modification of the effective field by introducing two counter-fields associated, respectively, with the eddy current and excess losses. Such a formulation is characterized by seven parameters with five parameters issued from the quasi-static Jiles-Atherton model. Thus, two new parameters related to these fields are added to that defined in the quasi-static model. The identification of these new parameters is based on the measurements of the volumetric energy density. To validate this formulation, measurements are carried out on grain non-oriented Fe-Si 3% electrical sheets.

Hamimid, M.; Mimoune, S. M.; Feliachi, M.

2011-07-01

404

Transcranial magnetic stimulation in different current directions activates separate cortical circuits.  

PubMed

Transcranial magnetic stimulation (TMS) to the primary motor cortex (M1) produces a series of corticospinal descending waves, with a direct (D) wave followed by several indirect (I) waves. TMS inducing posterior-anterior (PA) current in the brain predominantly recruits the early I1-wave, whereas anterior-posterior (AP) directed current preferentially recruits the late I3-wave. However, it is not known whether I-waves elicited by different current directions are mediated by the same neuronal populations. We studied the neuronal mechanisms mediating I-waves by examining the influence of short-latency afferent inhibition (SAI) on various I-waves. SAI was tested with electrical median nerve stimulation at the wrist followed by TMS to the contralateral M1 at different current directions. Surface electromyograms and single motor units were recorded from the first dorsal interosseous muscle. SAI was weaker for the AP compared with that for the PA current direction. With increasing median nerve stimulation intensities, SAI increased for the PA direction but showed a U-shaped relationship for the AP direction. SAI produced more inhibition of late I-waves generated by PA than those generated by AP current direction. We conclude that late I-waves generated by PA and AP current directions are mediated by different neuronal mechanisms. PMID:21148098

Ni, Zhen; Charab, Samer; Gunraj, Carolyn; Nelson, Aimee J; Udupa, Kaviraja; Yeh, I-Jin; Chen, Robert

2011-02-01

405

Magnetic force control technique in industrial application  

NASA Astrophysics Data System (ADS)

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

Nishijima, S.

2010-11-01

406

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

NASA Astrophysics Data System (ADS)

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

407

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

408

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

409

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

NASA Astrophysics Data System (ADS)

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

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

2011-11-01

410

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

Microsoft Academic Search

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

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

2009-01-01

411

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

SciTech Connect

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

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

2011-01-01

412

SLAB symmetric dielectric micron scale structures for high gradient electron acceleration.  

SciTech Connect

A class of planar microstructure is proposed which provide high accelerating gradients when excited by an infrared laser pulse. These structures consist of parallel dielectric slabs separated by a vacuum gap; the dielectric or the outer surface coating are spatially modulated at the laser wavelength along the beam direction so as to support a standing wave accelerating field. We have developed numerical and analytic models of the accelerating mode fields in the structure. We show an optimized coupling scheme such that this mode is excited resonantly with a large quality factor. The status of planned experiments on fabricating and measuring these planar structures will be described.

Rosenzweig, J. B.; Schoessow, P. V.

1999-06-12

413

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

PubMed

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

Sheha, Reda R

2012-12-15

414

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

PubMed

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

Ma, Yingxin; Huang, Sheng; Wang, Leyu

2013-11-15

415

Improving the binding capacity of Ni2+ decorated porous magnetic silica spheres for histidine-rich protein separation.  

PubMed

Biomagnetic immobilization of histidine-rich proteins based on the single-step affinity adsorption of transition metal ions continues to be a suitable practice as a cost effective and a up scaled alternative to the to multiple-step chromatographic separations. In our previous work, we synthesised Porous Magnetic silica (PMS) spheres by one-step hydrothermal-assisted modified-stöber method. The obtained spheres were decorated with Ni(2+) and Co(2+), and evaluated for the capture of a H6-Tagged green fluorescence protein (GFP-H6) protein. The binding capacity of the obtained spheres was found to be slightly higher in the case Ni(2+) decorated PMS spheres (PMSNi). However, comparing with commercial products, the binding capacity was found to be lower than the expected. In this way, the present work is an attempt to improve the binding capacity of PMSNi to histidine-rich proteins. We find that increasing the amount of Ni(2+) onto the surface of the PMS spheres leads to an increment of the binding capacity to GFP-H6 by a factor of two. On the other hand, we explore how the size of histidine-rich protein can affect the binding capacity comparing the results of the GFP-6H to those of the His-tagged ?-galactosidase (?-GLA). Finally, we demonstrate that the optimization of the magnetophoresis parameters during washing and eluting steps can lead to an additional improvement of the binding capacity. PMID:23010043

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

2013-01-01

416

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

PubMed

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

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

2007-05-01

417

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

NASA Astrophysics Data System (ADS)

We demonstrate that the configuration interaction (CI) approximation recaptures essential features of the exact (Bethe-ansatz) solution to the one-dimensional (1D) Hubbard model. As such, it provides a valuable route for describing effects that go beyond mean-field theory for strongly correlated electron systems in higher dimensions. The CI method systematically describes fluctuation and quantum tunneling corrections to the Hartree-Fock approximation (HFA). HFA predicts that doping a half-filled Hubbard chain leads to the appearance of charged spin polarons or charged domain-wall solitons in the antiferromagnetic background. The CI method, on the other hand, describes the quantum dynamics of these charged magnetic solitons and quantum tunneling effects between various mean-field configurations. In this paper, we test the accuracy of the CI method against the exact solution of the one-dimensional Hubbard model. We find remarkable agreement between the energy of the mobile charged bosonic domain wall (as given by the CI method) and the exact energy of the doping hole (as given by the Bethe ansatz) for the entire U/t range. The CI method also leads to a clear demonstration of the spin-charge separation in one dimension. Addition of one doping hole to the half-filled antiferromagnetic chain results in the appearance of two different carriers: a charged bosonic domain wall (which carries the charge but no spin) and a neutral spin-1/2 domain wall (which carries the spin but no charge).

Berciu, Mona; John, Sajeev

2000-04-01

418

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

PubMed

In this paper, the novel surface molecularly imprinted polymers based on dendritic-grafting magnetic nanoparticles were developed to enrich and separate glibenclamide in health foods. The density functional theory method was used to give theoretical directions to the synthesis of molecularly imprinted polymers. The polymers were prepared by using magnetic nanoparticles as supporting materials, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The characteristics of magnetic nanoparticles and polymers were measured by transmission electron microscope and SEM, respectively. The enriching ability of molecularly imprinted polymers was measured by Freundlich Isotherm. The molecularly imprinted polymers were used as dispersive SPE materials to enrich, separate, and detect glibenclamide in health foods by HPLC. The average recoveries of glibenclamide in spiked health foods were 81.46-93.53% with the RSD < 4.07%. PMID:23418142

Wang, Ruoyu; Wang, Yang; Xue, Cheng; Wen, Tingting; Wu, Jinhua; Hong, Junli; Zhou, Xuemin

2013-03-01

419

Preparation of anti-CD4 monoclonal antibody-conjugated magnetic poly(glycidyl methacrylate) particles and their application on CD4+ lymphocyte separation.  

PubMed

Novel immunomagnetic particles have been prepared for separation of CD4(+) lymphocytes. The magnetic nanoparticles with a diameter of approximately 5-6 nm were first synthesized by co-precipitation from ferrous and ferric iron solutions and subsequently encapsulated with poly(glycidyl methacrylate) (PGMA) by precipitation polymerization. Monoclonal antibody specific to CD4 molecules expressed on CD4(+) lymphocytes was conjugated to the surface of magnetic PGMA particles through covalent bonding between epoxide functional groups on the particle surface and primary amine groups of the antibodies. The generated immunomagnetic particles have successfully separated CD4(+) lymphocytes from whole blood with over 95% purity. The results indicated that these particles can be employed for cell separation and provide a strong potential to be applied in various biomedical applications including diagnosis, and monitoring of human diseases. PMID:21315903

Pimpha, Nuttaporn; Chaleawlert-umpon, Saowaluk; Chruewkamlow, Nuttapol; Kasinrerk, Watchara

2011-03-15

420

Electron Beam Characterization of a High-Gradient X-Band Photoinjector  

NASA Astrophysics Data System (ADS)

An X-band (8.548 GHz) rf photoinjector has been operated with a short pulse laser system to produce a high-brightness electron beam. The gun is designed to produce short (<1 ps) relativistic (5 MeV), low emittance (< ? mm-mrad, at 0.1 nC) electron bunches. The Ti:Sapphire laser system consists of a 12 fs oscillator and a 50 fs regenerative amplifier (Spitfire system from Positive Light) operating at a wavelength of 800 nm and a repetition rate of 1 kHz. The light is subsequently frequency tripled. Detailed experimental measurements of the e^- beam are planned, and the following diagnostics are available: 5 MeV magnetic spectrometer, 1 ps resolution visible streak camera, Cherenkov imaging system, matched Faraday cup, and quadrupole scan. A low-flux Compton scattering experiment is also under development which will help characterize the beam emittance and energy spread. This work was performed under the auspices of the DOE by LLNL under contract No. W-7405-ENG-48, and partially supported by NIH Contract No. N01-CO-97113 and AFOSR MURI Grant No. F49620-99-1-0297.

Gibson, D. J.; Hartemann, F. V.; Landahl, E. C.; Strong, F. W.; Troha, A. L.; Heritage, J. P.; Baldis, H. A.; Luhmann, N. C., Jr.; Ho, C. H.

2000-10-01

421

Erythrocyte Enrichment in Hematopoietic Progenitor Cell Cultures Based on Magnetic Susceptibility of the Hemoglobin  

PubMed Central

Using novel media formulations, it has been demonstrated that human placenta and umbilical cord blood-derived CD34+ cells can be expanded and differentiated into erythroid cells with high efficiency. However, obtaining mature and functional erythrocytes from the immature cell cultures with high purity and in an efficient manner remains a significant challenge. A distinguishing feature of a reticulocyte and maturing erythrocyte is the increasing concentration of hemoglobin and decreasing cell volume that results in increased cell magnetophoretic mobility (MM) when exposed to high magnetic fields and gradients, under anoxic conditions. Taking advantage of these initial observations, we studied a noninvasive (label-free) magnetic separation and analysis process to enrich and identify cultured functional erythrocytes. In addition to the magnetic cell separation and cell motion analysis in the magnetic field, the cell cultures were characterized for cell sedimentation rate, cell volume distributions using differential interference microscopy, immunophenotyping (glycophorin A), hemoglobin concentration and shear-induced deformability (elongation index, EI, by ektacytometry) to test for mature erythrocyte attributes. A commercial, packed column high-gradient magnetic separator (HGMS) was used for magnetic separation. The magnetically enriched fraction comprised 80% of the maturing cells (predominantly reticulocytes) that showed near 70% overlap of EI with the reference cord blood-derived RBC and over 50% overlap with the adult donor RBCs. The results demonstrate feasibility of label-free magnetic enrichment of erythrocyte fraction of CD34+ progenitor-derived cultures based on the presence of paramagnetic hemoglobin in the maturing erythrocytes.

Jin, Xiaoxia; Abbot, Stewart; Zhang, Xiaokui; Kang, Lin; Voskinarian-Berse, Vanessa; Zhao, Rui; Kameneva, Marina V.; Moore, Lee R.; Chalmers, Jeffrey J.; Zborowski, Maciej

2012-01-01

422

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

423

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

PubMed

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

Jastorff, Jan; Orban, Guy A

2009-06-01

424

Exploring the effect of Al2O3 ALD coating on a high gradient ILC single-cell cavity  

SciTech Connect

Encouraged by work at Argonne National Lab, we investigated atomic layer deposition technique (ALD) for high gradient superconducting RF cavities at JLab with an ALD coating system of Old Dominion University located on the JLab site. The goal of this study was to look into the possibility of coating a dielectric layer on top of RF niobium surface at a lower temperature of 120 C as compared to ANL coatings at 200 C to preserve niobium pentoxide on niobium surface. The initial coatings showed complete, but non-uniform coatings of the surface with several areas exhibiting discoloration, which was probably due to the temperature variation across the cavity surface. The initial coating showed a high RF losses, which were improved after discolored areas on the beam tubes were removed with HF rinse of the beam tubes only. The best result was 2 109 low field Q0 and Eacc = 18 MV/m limited by available power.

Grigory Eremeev, Anne-Marie Valente, Andy Wu, Diefeng Gu

2012-07-01

425

Magnetic, thermal and transport properties of phase-separated La0.27Nd0.4Ca0.33MnO3  

NASA Astrophysics Data System (ADS)

The magnetic, resistive and thermal properties of the phase-separated compound La0.27Nd0.4Ca0.33MnO3 have been experimentally studied. The sample is found to experience a charge/orbital ordering transition at ~175 K and an antiferromagnetic (AFM) transition at ~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 TC?110 K. However, the magnetic entropy change accompanying the AFM-FM transition is negligibly small when TCTN. A general relation between resistivity and magnetization, ? = A0Texp[(?-800m2)/T] (m = normalized magnetization), is established for the paramagnetic phase, which is also applicable to other compounds with different characters, such as the La0.67Ca0.33MnO3 film and the La0.474Bi0.193Ca0.33Mn0.994Cr0.006O3 and Eu0.55Sr0.45MnO3 ceramics. In the FM state, the resistivity is quite sensitive to the change of spin alignment and exhibits an exponential decrease with magnetization ? = ?0exp(-22.7m). Field-induced phase separation is believed to be responsible for the distinct properties of La0.27Nd0.4Ca0.33MnO3.

Wang, J. Z.; Sun, J. R.; Liu, G. J.; Hu, F. X.; Chen, R. J.; Zhao, T. Y.; Shen, B. G.

2008-08-01