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1

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

2

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

3

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

4

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

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

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

8

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

9

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

10

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

11

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

12

[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

13

Isotope Separation System.  

National Technical Information Service (NTIS)

This invention relates to the separation of isotopes and in particular to a magnetic separation system for ions selectively ionized by laser radiation. In this invention for the enrichment of exp 235 U isotopes the magnetic field is applied with a force w...

H. K. Forsen

1976-01-01

14

Separation system  

DOEpatents

A separation system for dewatering radioactive waste materials includes a disposal container, drive structure for receiving the container, and means for releasably attaching the container to the drive structure. Separation structure disposed in the container adjacent the inner surface of the side wall structure retains solids while allowing passage of liquids. Inlet port structure in the container top wall is normally closed by first valve structure that is centrifugally actuated to open the inlet port and discharge port structure at the container periphery receives liquid that passes through the separation structure and is normally closed by second valve structure that is centrifugally actuated to open the discharge ports. The container also includes coupling structure for releasable engagement with the centrifugal drive structure. Centrifugal force produced when the container is driven in rotation by the drive structure opens the valve structures, and radioactive waste material introduced into the container through the open inlet port is dewatered, and the waste is compacted. The ports are automatically closed by the valves when the container drum is not subjected to centrifugal force such that containment effectiveness is enhanced and exposure of personnel to radioactive materials is minimized.

Rubin, Leslie S. (Newton, MA)

1986-01-01

15

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

16

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

17

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

18

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

19

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

20

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

21

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

41

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

42

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

43

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

44

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

45

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

46

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

SciTech Connect

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

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

2009-10-15

47

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

48

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

49

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

50

Noise suppressing capillary separation system  

DOEpatents

A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

Yeung, Edward S. (Ames, IA); Xue, Yongjun (Norwich, NY)

1996-07-30

51

On Power System Controlled Separation  

Microsoft Academic Search

This paper describes verification of five conjectures related to power system controlled separation. It attempts to verify that the location of uncontrolled separation (loss of synchronism or out-of-step operation) is independent of the location and severity (short-circuit duty or duration) of the initial faults, that the location depends on the prevailing network configuration and load level, and that it takes

M. M. Adibi; R. J. Kafka; Sandeep Maram; Lamine M. Mili

2006-01-01

52

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

53

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

54

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

55

Noise suppressing capillary separation system  

DOEpatents

A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans. 13 figs.

Yeung, E.S.; Xue, Y.

1996-07-30

56

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

57

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

58

Electro-expulsive separation system  

NASA Technical Reports Server (NTRS)

An electro-expulsive system has one or more overlapped conductors, each comprising a flexible ribbon conductor, which is folded back on itself. The conductors are embedded in an elastomeric material. Large current pulses are fed to the conductors from power storage units. As a result of the antiparallel currents, the opposed segments of a conductor are forcefully separated and the elastomeric material is distended. Voids in the elastomer aid the separation of the conductor segments. The distention is almost instantaneous when a current pulse reaches the conductor and the distention tends to remove any solid body on the surface of the elastomeric material.

Haslim, Leonard A. (inventor); Lee, Robert D. (inventor)

1987-01-01

59

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

60

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

61

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

62

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

63

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

64

Magnetic Bearing System.  

National Technical Information Service (NTIS)

A magnetic bearing system is described which includes a high magnetic permeability interior disc member that is symmetrical about a longitudinal z axis. An annular member of high magnetic permeability is coaxial with and surrounds the disc, but is mechani...

P. A. Studer

1975-01-01

65

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

66

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

67

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

68

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

69

Superparamagnetism in Magnetically Dilute Systems  

Microsoft Academic Search

Superparamagnetic behavior observed in magnetically dilute systems is discussed. The clusters that behave like superparamagnetic fine particles are ferromagnetic or ferrimagnetic regions separated magnetically from the matrix, because these regions are surrounded by nonmagnetic atoms. The magnetic properties of dilute oxide systems such as: 0.9 ZnFe2O4-0.1 NiFe2O4; 0.9 FeTiO3-0.1 Fe2O3; and Y1.5Ca1.5Fe4.5Sn1.5O12 are better understood if we take into account

Yoshikazu Ishikawa

1964-01-01

70

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

71

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

72

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...

73

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

74

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

75

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

76

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

77

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

78

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

79

Large gap magnetic suspension system  

NASA Technical Reports Server (NTRS)

The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

Abdelsalam, Moustafa K.; Eyssa, Y. M.

1991-01-01

80

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

81

Centrifugal separator devices, systems and related methods  

DOEpatents

Centrifugal separator devices, systems and related methods are described. More particularly, fluid transfer connections for a centrifugal separator system having support assemblies with a movable member coupled to a connection tube and coupled to a fixed member, such that the movable member is constrained to movement along a fixed path relative to the fixed member are described. Also, centrifugal separator systems including such fluid transfer connections are described. Additionally, methods of installing, removing and/or replacing centrifugal separators from centrifugal separator systems are described.

Meikrantz, David H. (Idaho Falls, ID); Law, Jack D. (Pocatello, ID); Garn, Troy G. (Idaho Falls, ID); Todd, Terry A. (Aberdeen, ID); Macaluso, Lawrence L. (Carson City, NV)

2012-03-20

82

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

83

RHIC magnet electrical system  

NASA Astrophysics Data System (ADS)

The RHIC magnet electrical system consists primarily of the power converters that are used to energize the superconducting magnets in the collider ring, the power distribution system (both room temperature and superconducting) to deliver that power from the converters to the magnets, a detection system to monitor for quenches in the magnets and superconducting cables, and a protection system to remove power from the superconductors if a quench is detected. This system also has major interfaces with the Control System for commands, status monitoring, current setting and analog monitoring of the power supplies, and with Conventional Facilities for power distribution of the mains at and below the 480VAC level.

Bruno, D.; Eng, W.; Feng, P. K.; Ganetis, G.; Lambiase, R. F.; Louie, W.

2003-03-01

84

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

85

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

86

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

87

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

88

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

89

Quality testing of an innovative cascade separation system for multiple cell separation  

NASA Astrophysics Data System (ADS)

Isolation of different cell types from mixed samples in one separation step by FACS is feasible but expensive and slow. It is cheaper and faster but still challenging by magnetic separation. An innovative bead-based cascade-system (pluriSelect GmbH, Leipzig, Germany) relies on simultaneous physical separation of different cell types. It is based on antibody-mediated binding of cells to beads of different size and isolation with sieves of different mesh-size. We validated pluriSelect system for single parameter (CD3) and simultaneous separation of CD3 and CD15 cells from EDTA blood-samples. Results were compared with those obtained by MACS (Miltenyi-Biotech) magnetic separation (CD3 separation). pluriSelect separation was done in whole blood, MACS on Ficoll gradient isolated leukocytes, according to the manufacturer's protocols. Isolated and residual cells were immunophenotyped (7-color 8-antibody panel (CD3; CD16/56; CD4; CD8; CD14; CD19; CD45; HLADR) on a CyFlowML flow cytometer (Partec GmbH). Cell count (Coulter), purity, yield and viability (7-AAD exclusion) were determined. There were no significant differences between both systems regarding purity (92-98%), yield (50-60%) and viability (92-98%) of isolated cells. PluriSelect separation was slightly faster than MACS (1.15 h versus 1.5h). Moreover, no preenrichment steps were necessary. In conclusion, pluriSelect is a fast, simple and gentle system for efficient simultaneous separation of two cell subpopulation directly from whole blood and can provide a simple alternative to FACS. The isolated cells can be used for further research applications.

Pierzchalski, Arkadiusz; Moszczynska, Aleksandra; Albrecht, Bernd; Heinrich, Jan-Michael; Tarnok, Attila

2012-02-01

90

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

91

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

92

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

93

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

94

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

95

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

96

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

97

Separating key management from file system security  

Microsoft Academic Search

Abstract No secure network file system has ever grown to span the Internet. Existing systems all lack adequate key management for security at a global scale. Given the diversity of the Internet, any particular mechanism a file system employs to manage,keys will fail to support many types of use. We propose separating key management,from file system security, letting the world

David Mazières; Michael Kaminsky; M. Frans Kaashoek; Emmett Witchel

2000-01-01

98

Separating key management from file system security  

Microsoft Academic Search

No secure network file system has ever grown to span the Internet. Existing systems all lack adequate key management for security at a global scale. Given the diversity of the Internet, any particular mechanism a file system employs to manage keys will fail to support many types of use.We propose separating key management from file system security, letting the world

David Mazières; Michael Kaminsky; M. Frans Kaashoek; Emmett Witchel

1999-01-01

99

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

100

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

101

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

102

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

103

Pillow seal system at the BigRIPS separator  

NASA Astrophysics Data System (ADS)

We have designed and installed a pillow seal system for the BigRIPS fragment separator at the RIKEN Radioactive Isotope Beam Factory (RIBF) to facilitate remote maintenance in a radioactive environment. The pillow seal system is a device to connect a vacuum chamber and a beam tube. It allows quick attachment and detachment of vacuum connections in the BigRIPS separator and consists of a double diaphragm with a differential pumping system. The leakage rate achieved with this system is as low as 10-9 Pa m3/s. We have also designed and installed a local radiation-shielding system, integrated with the pillow seal system, to protect the superconducting magnets and to reduce the heat load on the cryogenic system. We present an overview of the pillow seal and the local shielding systems.

Tanaka, K.; Inabe, N.; Yoshida, K.; Kusaka, K.; Kubo, T.

2013-12-01

104

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

105

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

106

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

107

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

108

Isotope separation system experiments at the TSTA  

SciTech Connect

The recent results of the Isotope Separation System (ISS) operations at the Tritium Systems Test Assembly (TSTA) with 100 g of tritium indicate that the system generally satisfies design goals, while system stability problems remain to be solved. We configured the ISS system for the three column mode to eliminate such instability and operated it for six days. Fluctuations in flows and liquid levels were improved. Column separation characteristics obtained were satisfactory and agreed with the numerical analysis. The amount of discharged tritium was an acceptable effluent level. This means that the existing ISS system can be used as a three column system and possibly be applied to numerous fuel concepts. Presently, a new laser Raman spectroscopic gas analyzer has been installed at the ISS. This on-line system enables studies of the ISS dynamic behavior for further stability and performance data. 12 refs., 10 figs., 2 tabs.

Inoue, M.; Konishi, S.; Yamanishi, T.; Ohira, S.; Watanabe, T.; Okuno, K.; Naruse, Y. (Japan Atomic Energy Research Inst., Tokyo (Japan)); Sherman, R.H.; Barnes, J.W.; Bartlit, J.R.; Anderson, J.L. (Los Alamos National Lab., NM (United States))

1991-01-01

109

Isotope separation system experiments at the TSTA  

SciTech Connect

The recent results of the Isotope Separation System (ISS) operations at the Tritium Systems Test Assembly (TSTA) with 100 g of tritium indicate that the system generally satisfies design goals, while system stability problems remain to be solved. In this paper, the authors configure the ISS system for the three column mode. which is one of the promising cascade configurations in a fusion fuel cycle, to eliminate such instability and operated it for six days. Fluctuations in flows and liquid levels were improved. Column separation characteristics obtained were satisfactory and agreed with the numerical analysis. The amount of discharged tritium was an acceptable effluent level. This means that the existing ISS system can be used as a three column system and possibly be applied to numerous fuel concepts. Presently, a new laser Raman spectroscopic gas analyzer has been installed at the ISS. This on-line system enables studies of the ISS dynamic behavior for further stability and performance data.

Inoue, M.; Konishi, S.; Yamanishi, T.; Ohira, S.; Watanabe, T.; Okuno, K.; Naruse, Y. (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tritium Engineering Lab.); Sherman, R.H.; Barnes, J.W.; Bartlit, J.R.; Anderson, J.L. (Los Alamos National Lab., NM (United States). Materials Science and Technology Div.)

1992-03-01

110

The RHIC magnet system  

Microsoft Academic Search

The magnet system of the collider consists of superconducting dipole, quadrupole and correction magnets for guiding and focusing the beams through the regular arcs of the machine lattice as well as into collision at the six interaction points. It is designed to allow operation in the energy range 30–100GeV\\/u. Operation with either equal or unequal ion species in the colliding

M. Anerella; J. Cottingham; J. Cozzolino; P. Dahl; Y. Elisman; J. Escallier; H. Foelsche; G. Ganetis; M. Garber; A. Ghosh; C. Goodzeit; A. Greene; R. Gupta; M. Harrison; J. Herrera; A. Jain; S. Kahn; E. Kelly; E. Killian; M. Lindner; W. Louie; A. Marone; G. Morgan; A. Morgillo; S. Mulhall; J. Muratore; S. Plate; A. Prodell; M. Rehak; E. Rohrer; W. Sampson; J. Schmalzle; W. Schneider; R. Shutt; G. Sintchak; J. Skaritka; R. Thomas; P. Thompson; P. Wanderer; E. Willen

2003-01-01

111

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

112

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

113

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

114

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

115

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

116

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

117

Tara 24 Mva Magnet System.  

National Technical Information Service (NTIS)

Power transmission, conversion, control, and regulation aspects of the Tara tandem mirror 24 mva magnet system are discussed in detail. The magnet coil set, magnetic field configuration and support vacuum chamber are described. It is shown that a complete...

M. P. J. Gaudreau M. S. Shuster V. J. Berkman P. Thomas

1986-01-01

118

Partial interlaminar separation system for composites  

NASA Technical Reports Server (NTRS)

This inventor relates to an interlaminar separation system for composites wherein a thin layer of a perforated foil film is interposed between adjacent laminae of a composite formed from prepreg tapes to thereby permit laminate adherence through the perforations and produce a composite structure having improved physical property characteristics.

Elber, W. (inventor)

1980-01-01

119

Design consideration for magnetically suspended flywheel systems  

NASA Technical Reports Server (NTRS)

Consideration is given to the design, fabrication, and testing of a magnetically suspended flywheel system for energy storage applications in space. The device is the prototype of a system combining passive suspension of the flywheel plate by samarium cobalt magnets and active control in the radial direction using eight separate magnetic coils. The bearing assembly was machined from a nickel-iron alloy, and the machine parts are all hydrogen annealed. Slots in the magnetic plate allow four independent quadrants for control. The motor/generator component of the system is a brushless dc-permanent magnetic/ironless engine using electronic communication. The system has been tested at over 2500 rpm with satisfactory results. The system characteristics of the flywheel for application in low earth orbit (LEO) are given in a table.

Anand, D.; Kirk, J. A.; Frommer, D. A.

1985-01-01

120

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

121

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

122

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

123

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

124

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

125

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

126

Hydrogen Isotope Separation Factor Measurement for Single Stage Hydrogen Separators and Parameters for a Large-Scale Separation System  

SciTech Connect

A Concept design for large-scale hydrogen ISS based on a single Pd alloy membrane separator cascade has been presented. Separators to investigate the feasibility of the Pd membrane separator cascade concept have been designed and the separation performance of the separators is given. Results show that the separation factors, which are between 1.4 and 1.8 at the operation temperature, are large enough for a practical separation system design. Estimation results indicate that a 2.0m{sup 2} Pd membrane is needed for a 20mol/h and 12 stages batch ISS, and an approximately 50m{sup 2} Pd membrane is needed for a 200mol/h and 26 stages ISS. It is clear that the separator cascade concept is both reasonable and practicable for large-scale hydrogen isotope separation.

Luo, D.L.; Xiong, Y.F.; Song, J.F.; Huang, G.Q. [China Academy of Engineering Physics (China)

2005-07-15

127

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

128

Synthesis of azeotropic batch distillation separation systems  

SciTech Connect

The sequencing of batch distillation systems, in particular batch distillation columns, can be complicated by the existence of azeotropes in the mixture. These azeotropes can form batch distillation regions where, depending on the initial feed to the batch column, the types of feasible products and separations are limited. It is very important that these distillation regions are known while attempting to synthesize sequences of batch columns so infeasible designs can be eliminated early on in the design phase. The distillation regions also give information regarding the feasible products that can be obtained when the mixture is separated by using a variety of batch column configurations. The authors will show how a tool for finding the batch distillation regions of a particular mixture can be used in the synthesis of batch distillation column sequences. These sequences are determined by the initial feed composition to the separation network. The network of all possible sequences will be generated by using state-task networks when batch rectifying, stripping, middle vessel, and extractive middle vessel columns are allowed. The authors do not determine which sequence is the best, as the best sequence will depend on the particular application to which one is applying the algorithms. They show an example problem for illustration of this technique.

Safrit, B.T. [Eastman Chemical Co., Kingsport, TN (United States)] [Eastman Chemical Co., Kingsport, TN (United States); Westerberg, A.W. [Carnegie Mellon Univ., Pittsburgh, PA (United States)] [Carnegie Mellon Univ., Pittsburgh, PA (United States)

1997-05-01

129

Incinerator and fume separator system and apparatus  

SciTech Connect

The present invention provides an incinerator and fume separator device and a method for burning such materials as refuse, tire chips and sewage sludge or combinations thereof as well as other combustible materials to generate steam to supply steam heat and/or electricity to towns, villages or individual establishments. One of the key features of the system is the use of a horizontal conduit, wherein gases are initially cooled by a water-cooled conduit, part of the particulate material being removed within this tubing by use of baffles and fly ash settling chambers. The gases proceed through this conduit at a relatively high velocity and then through various fume separators located along the conduit by which the gases are intimately mixed with a liquid alkaline solution, such as lime water, by the propelling action of a ribbed slinger or propellor type device, located within the separator which because of its high speed and shearing action produces a cyclonic effect, thereby insuring intimate contact between the acidic contaminants in the gas and the fine droplets of alkaline material. Located underneath the ribbed slinger is a backwardly curved fan to pull the gas-alkaline liquid mixture downward and insure an even more intimate mixing of the contaminated gases and alkaline liquid. The purified gases are then exhausted into the atmosphere. According to the present invention, a variety of trash materials can be incinerated to generate steam and the exhaust gases can be effectively purified.

Sosnowski, L.; Mathewson, T.

1984-06-12

130

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

131

2 COMMON COIL MAGNET SYSTEM  

Microsoft Academic Search

This paper introduces the common coil magnet system for the proposed very large hadron collider (VLHC) (1). In this system, the high energy booster (HEB), the injector to VLHC, is integrated as the iron dominated low field aperture within the coldmass of the common coil magnet design introduced earlier (2). This 4-in-1 magnet concept for a 2-in-1 machine should provide

Ramesh Gupta

132

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

133

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

134

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

135

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

136

Unconventional magnetism in imbalanced Fermi systems with magnetic dipolar interactions  

SciTech Connect

We study the magnetic structure of the ground state of an itinerant Fermi system of spin-1/2 particles with magnetic dipole-dipole interactions. We show that, quite generally, the spin state of particles depend on its momentum, i.e., spin and orbital degrees of freedom are entangled and taken separately are not 'good' quantum numbers. Specifically, we consider a uniform system with nonzero magnetization at zero temperature. Assuming the magnetization is along z axis, the quantum spin states are k-dependent linear combinations of eigenstates of the sigma{sub z} Pauli matrix. This leads to spin structures in momentum space and to the fact that the Fermi surfaces for 'up' and 'down' spins are not well defined. The system still has a cylindrical axis of symmetry along the magnetization axis. We also show that the self-energy has a universal structure which we determine based on the symmetries of the dipolar interaction and we explicitly calculated it in the Hartree-Fock approximation. We show that the bare magnetic moment of particles is renormalized due to particle-particle interactions and we give order of magnitude estimates of this renormalization effect. We estimate that the above mentioned dipolar effects are small but we discuss possible scenarios where this physics may be realized in future experiments.

Fregoso, Benjamin M.; Fradkin, Eduardo [Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States)

2010-06-01

137

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

138

Magnetic Membrane System  

DOEpatents

The present invention provides a membrane with magnetic particles. In one embodiment the membrane is created by mixing particles in a non-magnetic base. The membrane may act as an actuator, a sensor, a pump, a valve, or other device. A magnet is operatively connected to the membrane. The magnet acts on and changes the shape of the membrane.

McElfresh, Michael W.; (Livermore, CA); Lucas, Matthew S.; (Pasadena, CA)

2004-12-30

139

Superconducting bulk magnets for magnetic levitation systems  

NASA Astrophysics Data System (ADS)

The major applications of high-temperature superconductors have mostly been confined to products in the form of wires and thin films. However, recent developments show that rare-earth REBa 2Cu 3O 7- x and light rare-earth LREBa 2Cu 3O 7- x superconductors prepared by melt processes have a high critical-current density at 77 K and high magnetic fields. These superconductors will promote the application of bulk high-temperature superconductors in high magnetic fields; the superconducting bulk magnet for the Maglev train is one possible application. We investigated the possibility of using bulk magnets in the Maglev system, and examined flux-trapping characteristics of multi-superconducting bulks arranged in array.

Fujimoto, H.; Kamijo, H.

2000-06-01

140

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

141

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

142

Suppressed conductometric capillary electrophoresis separation systems  

SciTech Connect

A tubular cation-exchange membrane is installed at the end of a 60-cm-long 75-[mu]m-bore fused-silica capillary. A static dilute acid regenerant solution surrounds the membranes that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerant solution grounded, effective suppression of electrolytes such as solutions of alkalic metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 10--20 [mu]g/L range for a variety of anions; a typical separation requires 15 min. Applicability to a variety of real samples is demonstrated. 26 refs., 10 figs.

Dasgupta, P.K.; Bao, L. (Texas Tech Univ., Lubbock (United States))

1993-04-15

143

Metal separations using aqueous biphasic partitioning systems  

SciTech Connect

Aqueous biphasic extraction (ABE) processes offer the potential for low-cost, highly selective separations. This countercurrent extraction technique involves selective partitioning of either dissolved solutes or ultrafine particulates between two immiscible aqueous phases. The extraction systems that the authors have studied are generated by combining an aqueous salt solution with an aqueous polymer solution. They have examined a wide range of applications for ABE, including the treatment of solid and liquid nuclear wastes, decontamination of soils, and processing of mineral ores. They have also conducted fundamental studies of solution microstructure using small angle neutron scattering (SANS). In this report they review the physicochemical fundamentals of aqueous biphase formation and discuss the development and scaleup of ABE processes for environmental remediation.

Chaiko, D.J.; Zaslavsky, B.; Rollins, A.N.; Vojta, Y.; Gartelmann, J.; Mego, W. [Argonne National Lab., IL (United States). Chemical Technology Div.

1996-05-01

144

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

145

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

146

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 ...

147

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

148

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

149

The development of bilge separation sensor system for improving accuracy  

Microsoft Academic Search

Demand of enhanced bilge separation sensor system has been recently increased due to the severe regulation reinforcement of MEPC (marine environment production committee). Up to date bilge separation sensor has to be extremely accurate and highly reliable. To design and build such a bilge separator, a precise oily water separation level sensor that distinguishes oil from water is critical. Three

Woo-Seong Che; Kyong-Woo Kim; Young-Jin Hong

2006-01-01

150

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

151

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

152

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

153

Solar System Magnetism  

NSDL National Science Digital Library

In this activity, polystyrene spheres and strong magnets are used to represent the Sun and Earth, and their distinct magnetic fields. Participants construct and use a "field detector" to predict where the magnetic fields are, and "field bits" to form loops and trace the invisible magnetic fields of the Sun and Earth. The activity is designed to be used in an informal public outreach setting. It can also be modified for use as a simple classroom demonstration. Information sheets are provided which can be printed to go along with the activity station.

2011-01-01

154

CEBAF Separator Cavity Resonance Control System.  

National Technical Information Service (NTIS)

The CEBAF energy upgrade will increase the maximum beam energy from 6 GeV to 12 GeV available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three halls. The resulting increase in RF separator ca...

M. Wissmann C. Hovater A. Guerra T. Plawski

2005-01-01

155

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

156

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

157

Size separation of particulates in a trommel screen system  

Microsoft Academic Search

This paper describes the design and testing of a trommel screen system for the separation of undersized particulates. The trommel screen system consisted of a cylindrical separation device that rotated to perform size separation. A series of experiments were carried out at room temperature to demonstrate the screening efficiency of this method under different operating conditions. The dynamic model and

Yi-Shun Chen; Shu-San Hsiau; Hsuan-Yi Lee; Yau-Pin Chyou; Chia-Jen Hsu

2010-01-01

158

Potential micrometeoroid and orbital debris protection system using a gradient magnetic field and magnetic flux compression  

NASA Astrophysics Data System (ADS)

A system for using a magnetic field in conjunction with conventional shielding configurations to protect against micrometeoroid and orbital debris is presented. Analytical, numerical, and experimental studies of a conductor moving through a gradient magnetic field have been performed. The results show that in the high magnetic Reynolds number regime a conducting object will experience large forces that tend to deform it while moving through the gradient field. Additionally a configuration using magnetic flux compression is introduced to act as a magnetic shock absorber. Separately or together, this technology may augment or replace current protection designs for space systems.

Giffin, A.; Shneider, M. N.; Miles, R. B.

2010-08-01

159

Tribology of magnetic storage systems  

NASA Technical Reports Server (NTRS)

The construction and the materials used in different magnetic storage devices are defined. The theories of friction and adhesion, interface temperatures, wear, and solid-liquid lubrication relevant to magnetic storage systems are presented. Experimental data are presented wherever possible to support the relevant theories advanced.

Bhushan, Bharat

1992-01-01

160

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

161

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

162

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

163

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...

164

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

165

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

166

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

167

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

168

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

169

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

170

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

171

Separator-spacer for electrochemical systems  

DOEpatents

An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ); Newby, Kenneth R. (Berkeley Heights, NJ); Bellows, Richard J. (Westfield, NJ)

1983-08-02

172

Satisfaction With the Legal System and Adjustment to Marital Separation.  

ERIC Educational Resources Information Center

The rise in the American divorce rate since the early 1960's emphasizes the need to examine the factors associated with adjustment to marital separation. The impact of the legal system upon post-separation adjustment in Pennsylvania, which has adversary divorce statutes, is explored with 205 individuals, separated 26 months or less. Satisfaction…

Anderson, Elaine A.

173

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

174

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

175

Method for separating biological cells. [suspended in aqueous polymer systems  

NASA Technical Reports Server (NTRS)

A method for separating biological cells by suspending a mixed cell population in a two-phase polymer system is described. The polymer system consists of droplet phases with different surface potentials for which the cell populations exhibit different affinities. The system is subjected to an electrostatic field of sufficient intensity to cause migration of the droplets with an attendant separation of cells.

Brooks, D. E. (inventor)

1980-01-01

176

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.

177

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

178

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

179

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

180

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

181

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

182

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

183

Development of the 19 T high field magnet system  

Microsoft Academic Search

A high field magnet system, up to 19 tesla at 1.8K, with magnet bore of 75mm was developed. The magnet consists of Nb3Sn solenoids (3 sections) and NbTi solenoids (2 sections). A liquid helium vessel is divided into two parts (4.2K upper part and 1.8K lower part) by a fiberglass reinforced plastics separator. The central field is 17 tesla at

T. Kamikado; M. Taneda; O. Ozaki; M. Sugimoto; Y. Murakami; M. Yoshikawa; K. Matsumoto; R. Ogawa; Y. Kawate

1994-01-01

184

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

185

Stackel separability for Newton systems of cofactor type  

Microsoft Academic Search

A conservative Newton system (d\\/dt)^2 q = -grad V(q) in R^n is called separable when the Hamilton--Jacobi equation for the natural Hamiltonian H = (1\\/2) p^2 + V(q) can be solved through separation of variables in some curvilinear coordinates. If these coordinates are orhogonal, the Newton system admits n first integrals, which all have separable Stackel form with quadratic dependence

Stefan Rauch-Wojciechowski; Claes Waksjö

2003-01-01

186

Thermodynamic analysis of separating lead and antimony in chloride system  

Microsoft Academic Search

In chloride system, thermodynamic analysis is a useful guide to separate lead and antimony as well as to understand the separation mechanism. An efficient and feasible way for separating lead and antimony was discussed. The relationships of [Pb2+][Cl?]2—lg[Cl]T and E—lg[Cl]T in Pb-Sb-Cl-H2O system were studied, and the solubilities of lead chloride at different antimony concentrations were calculated based on principle

Jin-zhong CHEN; Hua-zhen CAO; Bo LI; Hai-jun YUAN; Guo-qu ZHENG; Tian-zu YANG

2009-01-01

187

Magnetic Launch Assist System Demonstration  

NASA Technical Reports Server (NTRS)

This Quick Time movie demonstrates the Magnetic Launch Assist system, previously referred to as the Magnetic Levitation (Maglev) system, for space launch using a 5 foot model of a reusable Bantam Class launch vehicle on a 50 foot track that provided 6-g acceleration and 6-g de-acceleration. Overcoming the grip of Earth's gravity is a supreme challenge for engineers who design rockets that leave the planet. Engineers at the Marshall Space Flight Center have developed and tested Magnetic Launch Assist technologies that could levitate and accelerate a launch vehicle along a track at high speeds before it leaves the ground. Using electricity and magnetic fields, a Magnetic Launch Assist system would drive a spacecraft along a horizontal track until it reaches desired speeds. A full-scale, operational track would be about 1.5-miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the takeoff, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

1999-01-01

188

The 13th International Conference on Magnetically Levitated Systems and Linear Drives MAGLEV 1993  

NASA Astrophysics Data System (ADS)

This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.

189

Nanoparticulated magnetic drug delivery systems: Preparation and magnetic characterization  

NASA Astrophysics Data System (ADS)

This paper describes how magnetic resonance can be successfully used as a tool to help customize and quantify nanosized magnetic particles while labeling cells and administered in animals for targeting different biological sites. Customization of magnetic nanoparticles is addressed here in terms of production of complex magnetic drug delivery systems whereas quantification of magnetic nanoparticle in different biological compartments emerges as a key experimental information to assess time-dependent magnetic nanoparticle biodistribution profiles. Examples of using magnetic resonance in unfolding information regarding the pharmacokinetics of intravenously-injected surface-functionalized magnetic nanoparticles in animals are included in the paper.

Morais, P. C.

2010-03-01

190

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

191

Separation of aqueous two-phase polymer systems in microgravity  

NASA Technical Reports Server (NTRS)

Phase separation of polymer systems in microgravity is studied in aircraft flights to prepare shuttle experiments. Short duration (20 sec) experiments demonstrate that phase separation proceeds rapidly in low gravity despite appreciable phase viscosities and low liquid interfacial tensions (i.e., 50 cP, 10 micro N/m). Ostwald ripening does not appear to be a satisfactory model for the phase separation mechanism. Polymer coated surfaces are evaluated as a means to localize phases separated in low gravity. Contact angle measurements demonstrate that covalently coupling dextran or PEG to glass drastically alters the 1-g wall wetting behavior of the phases in dextran-PEG two phase systems.

Vanalstine, J. M.; Harris, J. M.; Synder, S.; Curreri, P. A.; Bamberger, S. B.; Brooks, D. E.

1984-01-01

192

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

193

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

194

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

195

Membrane separation systems---A research and development needs assessment  

SciTech Connect

Membrane based separation technology, a relative newcomer on the separations scene, has demonstrated the potential of saving enormous amounts of energy in the processing industries if substituted for conventional separation systems. Over 1 quad annually, out of 2.6, can possibly be saved in liquid-to-gas separations, alone, if membrane separation systems gain wider acceptance, according to a recent DOE/OIP (DOE/NBM-80027730 (1986)) study. In recent years great strides have been made in the field and offer even greater energy savings in the future when substituted for other conventional separation techniques such as distillation, evaporation, filtration, sedimentation, and absorption. An assessment was conducted by a group of six internationally known membrane separations experts who examined the worldwide status of research in the seven major membrane areas. This encompassed four mature technology areas: reverse osmosis, micorfiltration, ultrafiltration, and electrodialysis; two developing areas: gas separation and and pervaporation; and one emerging technology: facilitated transport. Particular attention was paid to identifying the innovative processes currently emerging, and even further improvements which could gain wider acceptance for the more mature membrane technology. The topics that were pointed out as having the greatest research emphasis are pervaporation for organic-organic separations; gas separation; micorfiltration; an oxidant-resistant reverse osmosis membrane; and a fouling-resistant ultrafiltration membrane. 35 refs., 6 figs., 22 tabs.

Baker, R.W. (Membrane Technology and Research, Inc., Menlo Park, CA (USA)); Cussler, E.L. (Minnesota Univ., Minneapolis, MN (USA). Dept. of Chemical Engineering and Materials Science); Eykamp, W. (California Univ., Berkeley, CA (USA)); Koros, W.J. (Texas Univ., Austin, TX (USA)); Riley, R.L. (Separation Systems Technology, San Diego, CA (USA)); Strathmann, H. (Fraunhofer-Institut fuer Grenzflaech

1990-03-01

196

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

197

Design and synthesis of reactive separation systems  

SciTech Connect

During the last decade there has been a rapid upturn in interest in reactive distillation. The chemical process industry recognizes the favorable economics of carrying out reaction simultaneously with distillation for certain classes of reacting systems, and many new processes have been built based on this technology. Interest is also increasing by academics and software vendors. Systematic design methods for reactive distillation systems have only recently begun to emerge. In this report we survey the available design techniques and point out the contributions made by our group at the University of Massachusetts.

Doherty, M.F.

1992-01-01

198

Phase separation in PMMA\\/silica sol-gel systems  

Microsoft Academic Search

The mechanism of phase separation of sol-gel alkoxy-derived silica systems obtained by acid catalysis in the presence of poly(methyl methacrylate) (PMMA) and tetrahydrofuran was investigated by light scattering. Spinodal decomposition (SD) was confirmed for systems with intermediate PMMA\\/alkoxy compositions occurring with a simultaneous viscosity increase. The initial stages of phase separation followed the linear theory proposed by Cahn. For systems

Kátia Fraga Silveira; Inez Valéria P. Yoshida; Suzana Pereira Nunes

1995-01-01

199

Systems of Kowalevski type and discriminantly separable polynomials  

NASA Astrophysics Data System (ADS)

Starting from the notion of discriminantly separable polynomials of degree two in each of three variables, we construct a class of integrable dynamical systems. These systems can be integrated explicitly in genus two theta-functions in a procedure which is similar to the classical one for the Kowalevski top. The discriminantly separable polynomials play the role of the Kowalevski fundamental equation. Natural examples include the Sokolov systems and the Jurdjevic elasticae.

Dragovi?, Vladimir; Kuki?, Katarina

2014-03-01

200

Magnetoresistive phenomena in nanoscale magnetic systems  

NASA Astrophysics Data System (ADS)

Nanomagnetic materials are playing an increasingly important role in modern technologies. A particular area of interest involves the interplay between magnetism and electric transport, i.e. magnetoresistive properties. Future generations of field sensors and memory elements will have to be on a length scale of a few nanometers or smaller. Magnetoresistive properties of such nanoscale objects exhibit novel features due to reduced dimensionality, complex surfaces and interfaces, and quantum effects. In this dissertation theoretical aspects of three such nanoscale magnetoresistive phenomena are discussed. Very narrow magnetic domain walls can strongly scatter electrons leading to an increased resistance. Specifically, this dissertation will cover the newly predicted effect of magnetic moment softening in magnetic nanocontacts or nanowires. Atomically thin domain walls in Ni exhibit a reduction, or softening, of the local magnetic moments due to the noncollinearity of the magnetization. This effect leads to a strong enhancement of the resistance of a domain wall. Magnetic tunnel junctions (MTJs) consist of two ferromagnetic electrodes separated by a thin layer of insulating material through which current can be carried by electron tunneling. The resistance of an MTJ depends on the relative orientation of the magnetization of the two ferromagnetic layers, an effect known as tunneling magnetoresistance (TMR). A first-principles analysis of CoFeB|MgO|CoFeB MTJs will be presented. Calculations reveal that it is energetically favorable for interstitial boron atoms to reside at the interface between the electrode and MgO tunneling barrier, which can be detrimental to the TMR effect. Anisotropic magnetoresistance (AMR) is the change in resistance of a ferromagnetic system as the orientation of the magnetization is altered. In this dissertation, the focus will be on AMR in the tunneling regime. Specifically we will present new theoretical results on tunneling AMR (TAMR) in two systems: (i) planar MTJs with CoFe electrodes and (ii) fully broken magnetic break junctions. In both cases electronic resonances in the electrodes lead to complex angular and bias dependence of the TAMR. The theoretical studies demonstrate the basic physical phenomenon behind recent experimental data.

Burton, John D.

201

Using separation of concerns for embedded systems design  

Microsoft Academic Search

Embedded systems are commonly abstracted as collections of interacting components. This perspective has lead to the insight that component behaviors can be defined separately from admissible component interactions. We show that this separation of concerns does not imply that component behaviors can be defined in isolation from their envisioned interaction models. We argue that a type of behavior\\/interaction co-design must

Ethan K. Jackson; Janos Sztipanovits

2005-01-01

202

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

203

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

204

Designing magnetic systems for reliability  

SciTech Connect

Designing magnetic system is an iterative process in which the requirements are set, a design is developed, materials and manufacturing processes are defined, interrelationships with the various elements of the system are established, engineering analyses are performed, and fault modes and effects are studied. Reliability requires that all elements of the design process, from the seemingly most straightforward such as utilities connection design and implementation, to the most sophisticated such as advanced finite element analyses, receives a balanced and appropriate level of attention. D.B. Montgomery's study of magnet failures has shown that the predominance of magnet failures tend not to be in the most intensively engineered areas, but are associated with insulation, leads, ad unanticipated conditions. TFTR, JET, JT-60, and PBX are all major tokamaks which have suffered loss of reliability due to water leaks. Similarly the majority of causes of loss of magnet reliability at PPPL has not been in the sophisticated areas of the design but are due to difficulties associated with coolant connections, bus connections, and external structural connections. Looking towards the future, the major next-devices such as BPX and ITER are most costly and complex than any of their predecessors and are pressing the bounds of operating levels, materials, and fabrication. Emphasis on reliability is a must as the fusion program enters a phase where there are fewer, but very costly devices with the goal of reaching a reactor prototype stage in the next two or three decades. This paper reviews some of the magnet reliability issues which PPPL has faced over the years the lessons learned from them, and magnet design and fabrication practices which have been found to contribute to magnet reliability.

Heitzenroeder, P.J.

1991-01-01

205

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

206

Cargo/Ballast Separation by Dual Membrane System.  

National Technical Information Service (NTIS)

The patent application concerns a ballasting system for oil tankers and other ships for separating the oil and the water ballast which eliminates oil contamination and pollution in ballasting and deballasting ships. Flexible fabric-reinforced or stretchab...

F. S. Hering J. I. Schwartz

1974-01-01

207

The Tara 24 mva magnet system  

SciTech Connect

Power transmission, conversion, control, and regulation aspects of the Tara tandem mirror 24 mva magnet system are discussed in detail. The magnet coil set, magnetic field configuration and support vacuum chamber are described. It is shown that a complete turn key pulse magnet power system has been built for under $21/kW.

Gaudreau, M.P.J.; Shuster, M.S.; Berkman, V.J.; Thomas, P.

1986-09-01

208

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

209

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

210

Influence of rotation on BN separation in binary particle system  

NASA Astrophysics Data System (ADS)

Granular particles systems under vertical vibration exhibit Brazilian Nut separation (BN), Reversed BN (RBN) separation or transitional phases at different vibrating conditions. In the present work, we investigate the influence of rotation on the BN separation of a binary granular particle system by changing rotational speed. 13X molecular sieve particles with diameter 6.00 mm and 0.60 mm are used. Vibration frequency f is 30 Hz and dimensionless acceleration ? is 1.52 or 1.75, in which the particle system mainly exhibits BN separation tendency. Rotational speed ? varies from 0 to 150rpm, while the upper surface of the particle system maintains flat. We took the pictures of the particles distribution and measured the particles mass layer by layer to obtain the 3-D distribution of the particles. The results show that rotation enhances the BN separation tendency at slow rotational speed. The BN separation becomes strongest when ? is approximately 50rpm, then the BN separation tendency reduces as ? continues to increase. A butterfly pattern appears in the middle particles layer under the simultaneous stimulations of vibration and rotation.

Wu, Ping; Wang, Shuang; Xie, Ziang; Huang, Yuming; Tong, Lige; Zhang, Peikun; Yin, Shaowu; Liu, Chuanping; Wang, Li

2013-06-01

211

Toroidal magnet system  

DOEpatents

In a plasma device having a toroidal plasma containment vessel, a toroidal field-generating coil system includes fixed linking coils each formed of first and second sections with the first section passing through a central opening through the containment vessel and the second section completing the linking coil to link the containment vessel. A plurality of removable unlinked coils are each formed of first and second C-shaped sections joined to each other at their open ends with their bights spaced apart. The second C-shaped section of each movable coil is removably mounted adjacent the second section of a linking coil, with the containment vessel disposed between the open ends of the first and second C-shaped sections. Electric current is passed through the linking and removable coils in opposite sense in the respective adjacent second sections to produce a net toroidal field.

Ohkawa, Tihiro (La Jolla, CA); Baker, Charles C. (Naperville, IL)

1981-01-01

212

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

213

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

214

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

215

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

216

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...

217

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

218

Membrane separation systems---A research and development needs assessment  

SciTech Connect

Industrial separation processes consume a significant portion of the energy used in the United States. A 1986 survey by the Office of Industrial Programs estimated that about 4.2 quads of energy are expended annually on distillation, drying and evaporation operations. This survey also concluded that over 0.8 quads of energy could be saved in the chemical, petroleum and food industries alone if these industries adopted membrane separation systems more widely. Membrane separation systems offer significant advantages over existing separation processes. In addition to consuming less energy than conventional processes, membrane systems are compact and modular, enabling easy retrofit to existing industrial processes. The present study was commissioned by the Department of Energy, Office of Program Analysis, to identify and prioritize membrane research needs in light of DOE's mission. Each report will be individually cataloged.

Baker, R.W. (Membrane Technology and Research, Inc., Menlo Park, CA (USA)); Cussler, E.L. (Minnesota Univ., Minneapolis, MN (USA). Dept. of Chemical Engineering and Materials Science); Eykamp, W. (California Univ., Berkeley, CA (USA)); Koros, W.J. (Texas Univ., Austin, TX (USA)); Riley, R.L. (Separation Systems Technology, San Diego, CA (USA)); Strathmann, H. (Fraunhofer-Institut fuer Grenzflaech

1990-04-01

219

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

220

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

221

Current Driven Magnetic Damping in Dipolar-Coupled Spin System  

PubMed Central

Magnetic damping of the spin, the decay rate from the initial spin state to the final state, can be controlled by the spin transfer torque. Such an active control of damping has given birth to novel phenomena like the current-driven magnetization reversal and the steady spin precession. The spintronic devices based on such phenomena generally consist of two separate spin layers, i.e., free and pinned layers. Here we report that the dipolar coupling between the two layers, which has been considered to give only marginal effects on the current driven spin dynamics, actually has a serious impact on it. The damping of the coupled spin system was greatly enhanced at a specific field, which could not be understood if the spin dynamics in each layer was considered separately. Our results give a way to control the magnetic damping of the dipolar coupled spin system through the external magnetic field.

Lee, Sung Chul; Pi, Ung Hwan; Kim, Keewon; Kim, Kwang Seok; Shin, Jaikwang; -In Chung, U

2012-01-01

222

Magnet system for the KEKB main ring  

NASA Astrophysics Data System (ADS)

KEKB is a two-ring electron-positron collider with asymmetric energies of 8 and 3.5 GeV to study CP violation in B meson decay. In KEKB, there are 21 types of magnets; about 1600 in total. About 430 dipole and quadrupole magnets were recycled from TRISTAN, the preceding program. All quadrupole magnets are equipped with vertical and horizontal steering dipole magnets. The number of steering magnets is about 1700. There are 212 sextupole magnets, and all of them are fixed on remotely controlled movers to adjust their positions to the beam passage. All main dipole magnets have back-leg coils to steer beams precisely. All quadrupole and sextupole magnets are equipped with correction coils to have a capability for beam-based alignment. Also one-turn coils are installed as well to each magnetic pole of the main magnets to monitor the magnetic flux in the case of trouble. The magnetic field in all magnets was measured and its quality strictly checked. After field measurement, the magnets were installed and precisely aligned. A cooling water system and a power supply system for these magnets were constructed. Magnet design was started in 1994, and construction of the two rings was completed in November 1998. The parameters of the magnets and the construction of the KEKB magnet system are described. Some of the problems experienced during this construction work are also presented.

Egawa, Kazumi; Endo, Kuninori; Fukuma, Hitoshi; Kubo, Tadashi; Masuzawa, Mika; Ohsawa, Yasunobu; Ohuchi, Norihito; Ozaki, Toshiyuki; Tsuchiya, Kiyosumi; Yoshida, Masato; Sugahara, Ryuhei

2003-02-01

223

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

224

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

225

Electromagnetic Mass Separator for Heavy Element Radioisotope Separation.  

National Technical Information Service (NTIS)

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

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

1980-01-01

226

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

227

Control of structure formation in phase-separating systems  

NASA Astrophysics Data System (ADS)

In this paper, we study the evolution of phase-separating binary mixtures which are subjected to alternate cooling and heating cycles. An initially homogeneous mixture is rapidly quenched to a temperature T1separation for a while and is then suddenly heated to a temperature T2>Tc. These cycles are repeated to create a domain morphology with multiple length scales, i.e., the structure factor is characterized by multiple peaks. For phase separation in d = 2 systems, we present numerical and analytical results for the emergence and growth of this multiple-scale morphology.

Singh, Awaneesh; Mukherjee, A.; Vermeulen, H. M.; Barkema, G. T.; Puri, Sanjay

2011-01-01

228

Development of magnetic drug delivery system using HTS bulk magnet  

NASA Astrophysics Data System (ADS)

Magnetic drug delivery system (MDDS) is the method which the magnetic seeded drug is injected into a blood vessel and then controlled and accumulated by a magnet located outside of the human body. A high accumulation efficiency of the drug to a local diseased part and reduction in side-effects to normal organs are expected by using MDDS. The most important element in MDDS is a magnetic field generator. The high temperature superconducting (HTS) bulk magnet which can generate high magnetic field and magnetic field gradient extending to a point distant from the magnet in several ten millimeters is necessary to achieve the MDDS. In this study, the computer simulation and model experiment were conducted in order to confirm the applicability of MDDS to ovary of the cow body.

Terada, T.; Fukui, S.; Mishima, F.; Akiyama, Y.; Izumi, Y.; Nishijima, S.

2008-09-01

229

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

230

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

231

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

232

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

233

Magnetic suspension systems for space applications  

NASA Technical Reports Server (NTRS)

An overview of techniques is presented used in the described magnetic suspension systems. Also a review is presented of the systems already developed, which demonstrate the usefulness, applicability, and flight readiness of magnetic suspension to a broad range of payloads and environments. The following subject areas are covered: programs overview; key concepts; magnetic suspension as an isolator and as a pointer; pointing and isolation systems; magnetic actuator control techniques; and test data.

Havenhill, Douglas G.; Wolke, Patrick J.

1991-01-01

234

Ares I Stage Separation System Design Certification Testing  

NASA Technical Reports Server (NTRS)

NASA is committed to the development of a new crew launch vehicle, the Ares I, that can support human missions to low Earth orbit (LEO) and the moon with unprecedented safety and reliability. NASA's Constellation program comprises the Ares I and Ares V launch vehicles, the Orion crew vehicle, and the Altair lunar lander. Based on historical precedent, stage separation is one of the most significant technical and systems engineering challenges that must be addressed in order to achieve this commitment. This paper surveys historical separation system tests that have been completed in order to ensure staging of other launch vehicles. Key separation system design trades evaluated for Ares I include single vs. dual separation plane options, retro-rockets vs. pneumatic gas actuators, small solid motor quantity/placement/timing, and continuous vs. clamshell interstage configuration options. Both subscale and full-scale tests are required to address the prediction of complex dynamic loading scenarios present during staging events. Test objectives such as separation system functionality, and pyroshock and debris field measurements for the full-scale tests are described. Discussion about the test article, support infrastructure and instrumentation are provided.

Mayers, Stephen L.; Beard, Bernard B.; Smith, R. Kenneth; Patterson, Alan

2009-01-01

235

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

236

Magnetic field intensified bi-enzyme system with in situ cofactor regeneration supported by magnetic nanoparticles.  

PubMed

Efficient dynamic interactions among cofactor, enzymes and substrate molecules are of primary importance for multi-step enzymatic reactions with in situ cofactor regeneration. Here we showed for the first time that the above dynamic interactions could be significantly intensified by exerting an external alternating magnetic field on magnetic nanoparticles-supported multi-enzymatic system so that the inter-particle collisions due to Brownian motion of nanoparticles could be improved. To that end, a multienzyme system including glutamate dehydrogenase (GluDH), glucose dehydrogenase (GDH) and cofactor NAD(H) were separately immobilized on silica coated Fe3O4 magnetic nanoparticles with an average diameter of 105 nm, and the effect of magnetic field strength and frequency on the kinetics of the coupled bi-enzyme reaction was investigated. It was found that at low magnetic field frequency (25 Hz and 100 Hz), increasing magnetic field strength from 9.8 to 161.1 Gs led to only very slight increase in reaction rate of the coupled bi-enzyme reaction expressed by glucose consumption rate. At higher magnetic field of 200 Hz and 500 Hz, reaction rate increased significantly with increase of magnetic field strength. When the magnetic field frequency was kept at 500 Hz, the reaction rate increased from 3.89 ?M/min to 8.11 ?M/min by increasing magnetic field strength from 1.3 to 14.2 Gs. The immobilized bi-enzyme system also showed good reusability and stability in the magnetic field (500 Hz, 14.2 Gs), that about 46% of original activity could be retained after 33 repeated uses, accounting for totally 34 days continuous operation. These results demonstrated the feasibility in intensifying molecular interactions among magnetic nanoparticle-supported multienzymes by using nano-magnetic stirrer for efficient multi-step transformations. PMID:23756150

Zheng, Muqing; Su, Zhiguo; Ji, Xiaoyuan; Ma, Guanghui; Wang, Ping; Zhang, Songping

2013-10-20

237

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

238

Common coil magnet system for VLHC  

Microsoft Academic Search

This paper introduces the common coil magnet system for the proposed Very Large Hadron Collider (VLHC). In this system, the high energy booster (HEB), the injector to VLHC, is integrated as the iron dominated low field aperture within the coldmass of the common coil magnet design introduced earlier. This 4-in-1 magnet concept for a 2-in-1 machine should provide a major

Ramesh Gupta; Lawrence Berkeley

1999-01-01

239

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

240

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

241

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

242

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

243

AGS fast kicker magnet system  

SciTech Connect

A new fast extraction system from the AGS will be implemented to improve the neutrino beam and to serve for ISABELLE injection. The fast kicker for the system is of an open C-type design with a field strength of 1.25 kG at 2650 amperes. The pulser system is a mismatched, discharge type PFN which is capable of delivering a pulse of 3000 amperes peak current at 30 kV dc, with a 2.7 ..mu..sec pulse width, 170 nsec rise time, and flat top ripple within +-1%. It also serves as a prototype for an ISA injection magnet, and is to be operated in UHV in the 10/sup -11/ Torr range. Special measures to achieve this goal are also discussed.

Weng, W T; Cottingham, J G; Foelsche, H; Frey, W; Ghoshroy, S; Schmidt, C; Tuozzolo, J

1981-01-01

244

Geometrically Frustrated Magnets as Model Systems.  

National Technical Information Service (NTIS)

The specific aim of this research program is to understand the cooperative magnetic properties of geometrically frustrated magnets which are model systems for the general phenomena of frustration. In the past year, we have continued studies of the dynamic...

P. Schiffer

2004-01-01

245

DIELECTROPHORESIS-BASED MICROFLUIDIC SEPARATION AND DETECTION SYSTEMS  

PubMed Central

Diagnosis and treatment of human diseases frequently requires isolation and detection of certain cell types from a complex mixture. Compared with traditional separation and detection techniques, microfluidic approaches promise to yield easy-to-use diagnostic instruments tolerant of a wide range of operating environments and capable of accomplishing automated analyses. These approaches will enable diagnostic advances to be disseminated from sophisticated clinical laboratories to the point-of-care. Applications will include the separation and differential analysis of blood cell subpopulations for host-based detection of blood cell changes caused by disease, infection, or exposure to toxins, and the separation and analysis of surface-sensitized, custom dielectric beads for chemical, biological, and biomolecular targets. Here we report a new particle separation and analysis microsystem that uses dielectrophoretic field-flow fractionation (DEP-FFF). The system consists of a microfluidic chip with integrated sample injector, a DEP-FFF separator, and an AC impedance sensor. We show the design of a miniaturized impedance sensor integrated circuit (IC) with improved sensitivity, a new packaging approach for micro-flumes that features a slide-together compression package and novel microfluidic interconnects, and the design, control, integration and packaging of a fieldable prototype. Illustrative applications will be shown, including the separation of different sized beads and different cell types, blood cell differential analysis, and impedance sensing results for beads, spores and cells.

Yang, Jun; Vykoukal, Jody; Noshari, Jamileh; Becker, Frederick; Gascoyne, Peter; Krulevitch, Peter; Fuller, Chris; Ackler, Harold; Hamilton, Julie; Boser, Bernhard; Eldredge, Adam; Hitchens, Duncan; Andrews, Craig

2009-01-01

246

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

247

High-Voltage Power Supply System for Laser Isotope Separation  

SciTech Connect

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs.

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-06-26

248

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

249

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

250

Method of making a partial interlaminar separation composite system  

NASA Technical Reports Server (NTRS)

An interlaminar separation system for composites is disclosed a thin layer of a perforated foil film is interposed between adjacent laminae of a composite formed from prepreg tapes. Laminae adherence takes place through the perforations and a composite structure with improved physical property characteristics is produced.

Elber, W. (inventor)

1981-01-01

251

Oil/Water Separation System with Sea Skimmer.  

National Technical Information Service (NTIS)

The design, construction, and testing of, an oil skimming and separation system capable of processing 30,000 gallons per hour, and operating on the open ocean under Sea State 3 conditions is described. A 45 x 26-foot twin-hulled barge, which contained an ...

1970-01-01

252

A Reverse Osmosis System for an Advanced Separation Process Laboratory.  

ERIC Educational Resources Information Center

Focuses on the development of a pilot unit for use in an advanced separations process laboratory in an effort to develop experiments on such processes as reverse osmosis, ultrafiltration, adsorption, and chromatography. Discusses reverse osmosis principles, the experimental system design, and some experimental studies. (TW)

Slater, C. S.; Paccione, J. D.

1987-01-01

253

Swing-out rail system separates overhead crane rails  

NASA Technical Reports Server (NTRS)

Swing-out rail system separates and reconnects the overhead traveling crane rails of a building to provide for the passage of a thick concrete radiation shield sliding door through the rails. In the swing-out position, the rail cantilevered from an axial shaft.

Pitkin, R. G.

1966-01-01

254

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

255

Gas, fluid and mineral solids separation and reclamation system  

SciTech Connect

The invention is a system which separates and reclaims a gas, e.g. methane, an aqueous fluid, e.g. water, and solids, e.g. coal from a slurry mixture. One application of the invention is in the degasification operations of underground mining. The system is hermetically constructed for the safe separation, collection and reclamation of the various components of the mixture. Included in the structure of the system are a substantially airtight enclosure which contains a trough-like passageway for delivering the mixture into the enclosure, gas vents and a collection manifold for collecting the released gas; a filter assembly for clarifying the aqueous fluid and reclaiming the fluid from the system for reuse, solids removal mechanisms for continuously transporting separated, settled solids from the enclosure interior to a location exterior to the system, a dual-functional mechanism for supplying make-up water to the system, a mechanism for controlling the supply of the make-up water, a dual-functional skimmer mechanism, an emergency outlet for releasing the mixture from the enclosure, and a mechanism for closing the emergency outlet during normal operation of the system and opening the outlet when necessary to accommodate high flows of mixture within the enclosure.

Wolde-Michael, G.

1985-05-07

256

Magnetic levitation self-regulating systems  

SciTech Connect

A magnet levitation self-regulating system is described comprising monotypic magnetic devices combined together by rigid nonmagnetic couplers; said magnetic device comprising two cylindrical parts extended along a cylinder generatrix: a. an iron core having a symmetrical C-shaped cross section and an air gap between its core shoes; and b. a permanent magnet having a rectangular cross-section disposed in said air gap; wherein all the iron cores of said magnetic devices are fixed on a common foundation by a first plurality of rigid nonmagnetic couplers and formed a stator assembly; all the permanent magnets of said magnetic devices are connected together by a second plurality of rigid non-magnetic couplers and form a levitator assembly; said permanent magnets of said levitator generate an original magnetic field and magnetize the stator cores; said stator cores create a secondary magnetic field; both said original and secondary magnetic fields create a magnetic levitation force that provides a stable hovering of said levitator in a resulting magnetic field of said system.

Tozoni, O.

1993-06-08

257

Hybrid membrane--PSA system for separating oxygen from air  

DOEpatents

A portable, non-cryogenic, oxygen generation system capable of delivering oxygen gas at purities greater than 98% and flow rates of 15 L/min or more is described. The system consists of two major components. The first component is a high efficiency membrane capable of separating argon and a portion of the nitrogen content from air, yielding an oxygen-enriched permeate flow. This is then fed to the second component, a pressure swing adsorption (PSA) unit utilizing a commercially available, but specifically formulated zeolite compound to remove the remainder of the nitrogen from the flow. The system is a unique gas separation system that can operate at ambient temperatures, for producing high purity oxygen for various applications (medical, refining, chemical production, enhanced combustion, fuel cells, etc . . . ) and represents a significant advance compared to current technologies.

Staiger, Chad L. (Albuquerque, NM); Vaughn, Mark R. (Albuquerque, NM); Miller, A. Keith (Albuquerque, NM); Cornelius, Christopher J. (Blackburg, VA)

2011-01-25

258

Development of portable superconducting bulk magnet system  

NASA Astrophysics Data System (ADS)

Recently a magnetic drug delivery system (MDDS) has been developing to navigate magnetic seeded drugs around diseased parts of the human body. To improve the magnetic drug delivery performance, a portable high temperature superconducting (HTS) bulk magnet system with high magnetic fields has been developed. This magnet system mainly consists of small bulk high temperature superconductors and a compact cryocooler. The materials of the high temperature superconductor are rare earth 123 single domain compounds (Gd-Ba-Cu-O). The bulk magnet was activated successfully using field-cooling magnetization under the superconducting solenoid magnet. The magnetic flux densities at the surface of the vacuum chambers that contain bulk magnets reached 5.07 T and 6.76 T using the static magnetic fields of 6 T and 10 T superconducting solenoid magnets, respectively. A cryocooler cooled them to 38.1 K and 39.1 K. It was clarified that the magnetic gradient was approximately 10 T/m at a position located 50 mm from the surface of the vacuum chambers.

Saho, N.; Nishijima, N.; Tanaka, H.; Sasaki, A.

2009-10-01

259

Dual Fan Separator within the Universal Waste Management System  

NASA Technical Reports Server (NTRS)

Since NASA's new spacecraft in development for both LEO and Deep Space capability have considerable crew volume reduction in comparison to the Space Shuttle, it is clear that NASA requires a smaller and less expensive commode. The UTAS Universal Waste Management System (UWMS) was designed to address these new constraints, resulting in an 80% volume reduction in the cabin while enhancing performance. Whereas all of the current space commodes use air flow to capture both urine and feces and separate air from the captured air/urine mixture, the UWMS commode and urine fans and the urine separator were combined into a single unit. This unit enables use of a single motor and motor controller, which provides considerable packaging and weight efficiency. In some of the intended platform applications for the UWMS, the urine is pumped to a water reclamation system. The ISS Urine Processor Assembly (UPA) system requires delivered urine to include less than 0.25% air inclusion. Air inclusion in centrifugal urine separators is greatly dependent on its rotational speed. To satisfy this requirement, a gear reducer was included, allowing the fans to rotate at a much higher speed than the separator. This new design, the Dual Fan Separator (DFS) has been designed, prototyped and tested. This paper will outline the studies and analysis performed to develop the design configuration for testing. The studies included a configuration trade study, dynamic stability analysis of the rotating bodies and a performance analysis of included labyrinth seals. NASA is considereing a program to fly the UWMS aboard the ISS as a flight experiment. The goal of the design activity is to elevate the Technical Readiness Level (TRL) of the Dual Fan Separator and determine if the concept is ready to be included in flight experiment deliverable.

Stapleton, Tom; Converse, Dave; Broyan, James Lee, Jr.

2014-01-01

260

Development and Characterization of Microfluidic Devices and Systems for Magnetic Bead-Based Biochemical Detection  

Microsoft Academic Search

This paper presents the development and characterization of a generic microfluidic system for magnetic bead-based biochemical detection. Microfluidic and electrochemical detection devices such as microvalves, flow sensors, biofilters, and immunosensors have been successfully developed and individually characterized in this work. Magnetically driven microvalves, pulsed-mode microflow sensors, magnetic particle separators as biofilters, and electrochemical immunosensors have been sep-arately fabricated and tested.

Jin-Woo Choi; Kwang W. Oh; Arum Han; C. Ajith Wijayawardhana; Chad Lannes; Shekhar Bhansali; Kevin T. Schlueter; William R. Heineman; H. Brian Halsall; Joseph H. Nevin; Arthur J. Helmicki; H. Thurman Henderson; Chong H. Ahn

2001-01-01

261

Combined ICR heating antenna for ion separation systems  

SciTech Connect

A combination of one- and two-wave antennas (one and two turns of conductors around a plasma cylinder, respectively) is proposed. This combined antenna localizes an RF field within itself. It is shown that spent nuclear fuel processing systems based on ICR heating of nuclear ash by such a combined antenna have high productivity. A theory of the RF field excitation in ICR ion separation systems is presented in a simple and compact form.

Timofeev, A. V. [Russian Research Centre Kurchatov Institute (Russian Federation)

2011-01-15

262

Computational Analysis of Enhanced Magnetic Bioseparation in Microfluidic Systems with Flow-Invasive Magnetic Elements  

PubMed Central

A microfluidic design is proposed for realizing greatly enhanced separation of magnetically-labeled bioparticles using integrated soft-magnetic elements. The elements are fixed and intersect the carrier fluid (flow-invasive) with their length transverse to the flow. They are magnetized using a bias field to produce a particle capture force. Multiple stair-step elements are used to provide efficient capture throughout the entire flow channel. This is in contrast to conventional systems wherein the elements are integrated into the walls of the channel, which restricts efficient capture to limited regions of the channel due to the short range nature of the magnetic force. This severely limits the channel size and hence throughput. Flow-invasive elements overcome this limitation and enable microfluidic bioseparation systems with superior scalability. This enhanced functionality is quantified for the first time using a computational model that accounts for the dominant mechanisms of particle transport including fully-coupled particle-fluid momentum transfer.

Khashan, S. A.; Alazzam, A.; Furlani, E. P.

2014-01-01

263

Rationale for two phase polymer system microgravity separation experiments  

NASA Technical Reports Server (NTRS)

The two-phase systems that result when aqueous solutions of dextran and poly(ethylene glycol) are mixed at concentrations above a few percent are discussed. They provide useful media for the partition and isolation of macromolecules and cell subpopulations. By manipulating their composition, separations based on a variety of molecular and surface properties are achieved, including membrane hydrophobic properties, cell surface charge, and membrane antigenicity. Work on the mechanism of cell partition shows there is a randomizing, nonthermal energy present which reduces separation resolution. This stochastic energy is probably associated with hydrodynamic interactions present during separation. Because such factors should be markedly reduced in microgravity, a series of shuttle experiments to indicate approaches to increasing the resolution of the procedure are planned.

Brooks, D. E.; Bamberger, S. B.; Harris, J. M.; Vanalstine, J.

1984-01-01

264

Combined electrophoretic-separation and electrospray method and system  

DOEpatents

A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary zone electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., [+-]2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit. 10 figs.

Smith, R.D.; Olivares, J.A.

1989-06-27

265

Combined electrophoretic-separation and electrospray method and system  

DOEpatents

A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary zone electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit.

Smith, Richard D. (Richland, WA); Olivares, Jose A. (Kennewick, WA)

1989-01-01

266

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

267

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

268

Self-Regulating Water-Separator System for Fuel Cells  

NASA Technical Reports Server (NTRS)

proposed system would perform multiple coordinated functions in regulating the pressure of the oxidant gas (usually, pure oxygen) flowing to a fuelcell stack and in removing excess product water that is generated in the normal fuel-cell operation. The system could function in the presence or absence of gravitation, and in any orientation in a gravitational field. Unlike some prior systems for removing product water, the proposed system would not depend on hydrophobicity or hydrophilicity of surfaces that are subject to fouling and, consequently, to gradual deterioration in performance. Also unlike some prior systems, the proposed system would not include actively controlled electric motors for pumping; instead, motive power for separation and pumping away of product water would be derived primarily from the oxidant flow and perhaps secondarily from the fuel flow. The net effect of these and other features would be to make the proposed system more reliable and safer, relative to the prior systems. The proposed system (see figure) would include a pressure regulator and sensor in the oxidant supply just upstream from an ejector reactant pump. The pressure of the oxidant supply would depend on the consumption flow. In one of two control subsystems, the pressure of oxidant flowing from the supply to the ejector would be sensed and used to control the speed of a set of a reciprocating constant-displacement pump so that the volumetric flow of nominally incompressible water away from the system would slightly exceed the rate at which water was produced by the fuel cell(s). The two-phase (gas/liquid water) outlet stream from the fuel cell(s) would enter the water separator, a turbinelike centrifugal separator machine driven primarily by the oxidant gas stream. A second control subsystem would utilize feedback derived from the compressibility of the outlet stream: As the separator was emptied of liquid water, the compressibility of the pumped stream would increase. The compressibility would be sensed, and an increase in compressibility beyond a preset point (signifying a decrease in water content below an optimum low level) would cause the outflow from the reciprocating pump to be diverted back to the separator to recycle some water.

Vasquez, Arturo; McCurdy, Kerri; Bradley, Karla F.

2007-01-01

269

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

270

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

271

Magnetization of planar four-fermion systems  

SciTech Connect

We consider a planar system of fermions, at finite temperature and density under a static magnetic field parallel to the two-dimensional plane. This magnetic field generates a Zeeman effect and then a spin polarization of the system. The critical properties are studied from the Landau's free energy. The possible observable consequences of the magnetization of planar systems such as polymer films and graphene are discussed.

Caldas, Heron [Departamento de Ciencias Naturais, Universidade Federal de Sao Joao del Rei, 36301-160 Sao Joao del Rei, MG (Brazil); Ramos, Rudnei O. [Departamento de Fisica Teorica, Universidade do Estado do Rio de Janeiro, 20550-013 Rio de Janeiro, RJ (Brazil)

2009-09-15

272

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

273

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

274

Superconducting magnet system U-25 MHD facility  

Microsoft Academic Search

The Argonne National Laboratory has designed and is constructing a superconducting dipole magnet system for use in the bypass loop of the U-25 MHD facility in Moscow. Presented in detail are the system design parameters. Reviewed are the magnet geometry, stability criteria, cryostat thermal and mechanical design, cryogenic system parameters, and controls. Details of the servo mechanism winding machine, the

R. Niemann; S. Wang; W. Pelczarski; J. Gonczy; K. Mataya; H. Ludwig; D. Hillis; H. Phillips; L. Turner; J. Purcell; D. Montgomery; J. Williams; A. Hatch; P. Marston; P. Smelser; V. Zenkevitch; L. Kirjenen; W. Young

1977-01-01

275

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

276

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

277

Particles sorting in micro-channel system utilizing magnetic tweezers and optical tweezers  

NASA Astrophysics Data System (ADS)

This study evaluates a method for separating magnetic microparticles in a micro channel by using embedded inverted-laser tweezers, a microflow pump, and a micro magnet. Various particles were separated using optical and/or magnetic tweezers, and were identified and counted to determine the dependence of the sorting rate on the channel flow velocity. The particle sorting experiment showed good separation results when the designed channel and magnetic tweezers were used. For magnetic particles, lower flow velocities corresponded to larger separating rates with a maximum separating rate of 81%. When the designed channel and optical tweezers were used, the polystyrene particle separating rate was as high as 94%. When both the optical tweezers and the magnetic tweezers were used, the optical tweezers were more effective in trapping polystyrene particles with flow velocities between 0.09 and 0.25 ?m/s. For flow velocities between 0.09 and 0.17 ?m/s, the separating rate for polystyrene particles reached 95% and the separating rate for magnetic particles reached 85%. This hybrid system can be applied to the separation of various particles in unknown mixtures.

Chung, Yung-Chiang; Chen, Po-Wen; Fu, Chao-Ming; Wu, Jian-Min

2013-05-01

278

Infinite-Order Symmetries for Quantum Separable Systems  

SciTech Connect

We develop a calculus to describe the (in general) infinite-order differential operator symmetries of a nonrelativistic Schroedinger eigenvalue equation that admits an orthogonal separation of variables in Riemannian n space. The infinite-order calculus exhibits structure not apparent when one studies only finite-order symmetries. The search for finite-order symmetries can then be reposed as one of looking for solutions of a coupled system of PDEs that are polynomial in certain parameters. Among the simple consequences of the calculus is that one can generate algorithmically a canonical basis for the space. Similarly, we can develop a calculus for conformal symmetries of the time-dependent Schroedinger equation if it admits R separation in some coordinate system. This leads to energy-shifting symmetries.

Miller, W. [School of Mathematics, University of Minnesota, Minneapolis (United States); Kalnins, E.G. [Department of Mathematics, University of Waikato, Hamilton (New Zealand); Kress, J.M. [School of Mathematics, University of New South Wales, Sydney (Australia); Pogosyan, G.S. [Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 (Russian Federation); Departamento de Matematicas, CUCEA, Universidad de Guadalayara (Mexico)

2005-10-01

279

Size based separation of microparticles using a dielectrophoretic activated system  

NASA Astrophysics Data System (ADS)

This work describes the separation of polystyrene microparticles suspended in deionized (DI) water according to their dimensions using a dielectrophoretic (DEP) system. The DEP system utilizes curved microelectrodes integrated into a microfluidic system. Microparticles of 1, 6, and 15 ?m are applied to the system and their response to the DEP field is studied at different frequencies of 100, 200, and 20 MHz. The microelectrodes act as a DEP barrier for 15 ?m particles and retain them at all frequencies whereas the response of 1 and 6 ?m particles depend strongly on the applied frequency. At 100 kHz, both particles are trapped by the microelectrodes. However, at 200 kHz, the 1 ?m particles are trapped by the microelectrodes while the 6 ?m particles are pushed toward the sidewalls. Finally, at 20 MHz, both particles are pushed toward the sidewalls. The experiments show the tunable performance of the system to sort the microparticles of various dimensions in microfluidic systems.

Khoshmanesh, Khashayar; Zhang, Chen; Nahavandi, Saeid; Tovar-Lopez, Francisco J.; Baratchi, Sara; Mitchell, Arnan; Kalantar-Zadeh, Kourosh

2010-08-01

280

Detection system for the St. George recoil mass separator  

NASA Astrophysics Data System (ADS)

The St. George recoil mass separator is designed for the study of low energy (?,?) reactions of astrophysical interest in inverse kinematics. The energy range of recoils will be 0.07 to 0.9 MeV/nucleon. A detection system is being developed for separating the recoils from the residual scattered beam at the focal plane. The detection system will consist of two position sensitive microchannel plate (MCPs) timing detectors separated by 50cm followed by a single sided silicon strip detector. Simulations were performed using the codes SIMION and GEANT4. Different designs for guiding the secondary electrons emitted from a thin carbon foil to the MCP were studied in the simulations. Good timing and position resolution and minimization of transmission loss due to grids were key factors in selecting the final design. Time of flight will be recorded between the two MCPs. The delay line technique will be used for extracting the position information from the MCPs. The energy of the recoils will be recorded by the Si detector. A dedicated vacuum chamber and the modular design of the detection system will facilitate future improvements and customization for particular experiments.

Kalkal, S.; Hinnefeld, J.; Morales, L.; Robertson, D.; Stech, E.; Berg, G. P. A.; Gorres, J.; Couder, M.; Wiescher, M.

2012-10-01

281

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

282

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

283

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

284

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

285

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

286

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

287

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

288

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

289

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

290

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

291

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

292

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

293

Separation of variables in an asymmetric cyclidic coordinate system  

NASA Astrophysics Data System (ADS)

A global analysis is presented of solutions for Laplace's equation on three-dimensional Euclidean space in one of the most general orthogonal asymmetric confocal cyclidic coordinate systems which admit solutions through separation of variables. We refer to this coordinate system as five-cyclide coordinates since the coordinate surfaces are given by two cyclides of genus zero which represent inversions of each other with respect to the unit sphere, a cyclide of genus one, and two disconnected cyclides of genus zero. This coordinate system is obtained by stereographic projection of sphero-conal coordinates on four-dimensional Euclidean space. The harmonics in this coordinate system are given by products of solutions of second-order Fuchsian ordinary differential equations with five elementary singularities. The Dirichlet problem for the global harmonics in this coordinate system is solved using multiparameter spectral theory in the regions bounded by the asymmetric confocal cyclidic coordinate surfaces.

Cohl, H. S.; Volkmer, H.

2013-06-01

294

Ultrahigh vacuum compatible superconducting quantum interference device magnetometer system for studies of magnetic thin films  

Microsoft Academic Search

In this article, we describe an ultrahigh vacuum (UHV) compatible superconducting quantum interference device (SQUID) magnetometer system for investigations of surface, interface, and thin film magnetism. This system provides a new capability for a commercial SQUID magnetometer to characterize freshly deposited thin film samples transported from a separate molecular-beam epitaxy deposition facility without breaking vacuum. Magnetic measurements can be performed

S. Spagna; R. E. Sager; M. B. Maple

1995-01-01

295

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

296

Cooling system for superconducting magnet  

DOEpatents

A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir.

Gamble, Bruce B. (Wellesley, MA); Sidi-Yekhlef, Ahmed (Framingham, MA)

1998-01-01

297

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

298

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

299

KEKB INJECTION KICKER MAGNET SYSTEM  

Microsoft Academic Search

The design, construction and operation of the KEKB injection kicker magnets are described. The magnet operates up to 35kV and 2kA with magnetic field rise and fall time of around 1µsec each. The pulsers operate at repetition rate of between 1 and 50 Hz as dictated by the operational mode of KEKB. The orbit of kicked bunches are observed with

T. Mimashi; M. Kikuchi; H. Nakayama; K. Satoh; M. Tobiyama; Tsukuba Ibaraki; A. Tokuchi

300

On uncontrolled system separation in power system restoration  

Microsoft Academic Search

Since extended power outages causes severe stress on society and the restoration following a black out is a complex and time consuming task, efficient restoration strategies are needed. During the restoration, the power system undergoes continual changes and therefore it is subject to desired and undesired operations and failures which might be devastating. The main contribution of this paper is

F. Edstrom; L. Soder

2011-01-01

301

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

302

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

303

Separations technologies supporting the development of a deployable ATW system  

SciTech Connect

A program has been initiated for the purpose of developing the chemical separations technologies necessary to support a large Accelerator Transmutation of Waste (ATW) system capable of dealing with the projected inventory of spent fuel from the commercial nuclear power stations in the United States. The first several years of the program will be directed toward an elucidation of related technical issues and to the establishment, by means of comprehensive trade studies, of an optimum configuration of the elements of the chemical processing infrastructure required for support of the total ATW system. By adopting this sort of disciplined systems engineering approach, it is expected that development and demonstration costs can be minimized and that it will be possible to deploy an ATW system that is an environmentally sound and economically viable venture.

Laidler, J. J.

2000-01-07

304

Magnetic Susceptibility Measurement System for Small and Weak Magnetic Substances  

NASA Astrophysics Data System (ADS)

In this study a system is constructed which uses a force method for taking magnetic susceptibility measurements of small (< 100 mg) and weak (< 100x 10-6 emu/g) magnetic substances. The system is constructed with several pieces of readily available hardware. Some of the hardware includes a stable frame structure, a CAHN electrobalance, electromagnet, a thermocouple, a power supply, interfaces, and a personal computer. Each of these components is tested individually as well as together with other devices. Since the electrobalance is extremely sensitive the balance must be placed on a stable frame. The completed system is capable of studying the magnetic properties from room temperature to 77 K of a variety of samples. In addition, a novel method is developed to produce hysteresis loops for especially small and weak magnetic samples. Extensive testing is done to ensure the magnetization results obtained on known samples compare with what has been reported. Some of the samples that have been measured are MnO (TN was 122 K), CdSe (magnetic susceptibility was -0.3 x 10-6 emu/g) with iron attached ligands, FexTeyOz type samples with and without nickel, a YBaCuO superconductor, and cells doped with magnetite nanoparticles. The results are compared to measurements made with SQUID magnetometers.

Grant, Julius Reynard

305

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

306

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

307

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

308

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

309

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

310

Attractive and repulsive magnetic suspension systems overview  

NASA Technical Reports Server (NTRS)

Magnetic suspension systems can be used in a wide variety of applications. The decision of whether to use an attractive or repulsive suspension system for a particular application is a fundamental one which must be made during the design process. As an aid to the designer, we compare and contrast attractive and repulsive magnetic suspension systems and indicate whether and under what conditions one or the other system is preferred.

Cope, David B.; Fontana, Richard R.

1992-01-01

311

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

312

Control of Systems With Slow Actuators Using Time Scale Separation  

NASA Technical Reports Server (NTRS)

This paper addresses the problem of controlling a nonlinear plant with a slow actuator using singular perturbation method. For the known plant-actuator cascaded system the proposed scheme achieves tracking of a given reference model with considerably less control demand than would otherwise result when using conventional design techniques. This is the consequence of excluding the small parameter from the actuator dynamics via time scale separation. The resulting tracking error is within the order of this small parameter. For the unknown system the adaptive counterpart is developed based on the prediction model, which is driven towards the reference model by the control design. It is proven that the prediction model tracks the reference model with an error proportional to the small parameter, while the prediction error converges to zero. The resulting closed-loop system with all prediction models and adaptive laws remains stable. The benefits of the approach are demonstrated in simulation studies and compared to conventional control approaches.

Stepanyan, Vehram; Nguyen, Nhan

2009-01-01

313

Optimal Control Modification for Time-Scale Separated Systems  

NASA Technical Reports Server (NTRS)

Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. A model matching conditions in the transformed time coordinate results in an increase in the actuator command that effectively compensate for the slow actuator dynamics. Simulations demonstrate effectiveness of the method.

Nguyen, Nhan T.

2012-01-01

314

Preparation of a Magnetically Switchable Bioelectrocatalytic System Employing Cross-Linked Enzyme Aggregates in Magnetic Mesocellular Carbon Foam  

SciTech Connect

Nanostructured magnetic materials (NMMs)[1] have attracted much attention recently because of their broad biotechnological applications including support matrices for enzyme immobilization,[2] immunoassays,[3] drug delivery,[4] and biosensors.[ 5] Specifically, the easy separation and controlled placement of NMMs by means of an external magnetic field enables their application in the development of immobilized enzyme processes[2] and the construction of magnetically controllable bio-electrocatalytic systems.[5, 6] Herein, we demonstrate the use of immobilized enzymes in NMMs for magnetically switchable bio-electrocatalysis.

Lee, Jinwoo; Lee, Dohun; Oh, Eunkeu; Kim, Jaeyun; Kim, Young-Pil; Jin, Sunmi; Kim, Hak Sung; Hwang, Yosun; Kwak, Ja Hun; Park, Je-Geun; Shin, Chae-Ho; Kim, Jungbae; Hyeon, Taeghwan

2005-11-18

315

Modular transportable superconducting magnetic energy systems  

NASA Technical Reports Server (NTRS)

Design and cost studies were performed for the magnet components of mid-size (1-5 MWh), cold supported SMES systems using alternative configurations. The configurations studied included solenoid magnets, which required onsite assembly of the magnet system, and toroid and racetrack configurations which consisted of factory assembled modules. For each configuration, design concepts and cost information were developed for the major features of the magnet system including the conductor, electrical insulation, and structure. These studies showed that for mid-size systems, the costs of solenoid and toroid magnet configurations are comparable and that the specific configuration to be used for a given application should be based upon customer requirements such as limiting stray fields or minimizing risks in development or construction.

Lieurance, Dennis; Kimball, Foster; Rix, Craig

1995-01-01

316

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

317

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

318

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

319

Active tensor magnetic gradiometer system final report for Project MM–1514  

USGS Publications Warehouse

An interactive computer simulation program, based on physical models of system sensors, platform geometry, Earth environment, and spheroidal magnetically-permeable targets, was developed to generate synthetic magnetic field data from a conceptual tensor magnetic gradiometer system equipped with an active primary field generator. The system sensors emulate the prototype tensor magnetic gradiometer system (TMGS) developed under a separate contract for unexploded ordnance (UXO) detection and classification. Time-series data from different simulation scenarios were analyzed to recover physical dimensions of the target source. Helbig-Euler simulations were run with rectangular and rod-like source bodies to determine whether such a system could separate the induced component of the magnetization from the remanent component for each target. This report concludes with an engineering assessment of a practical system design.

Smith, David V.; Phillips, Jeffrey D.; Hutton, S. Raymond

2014-01-01

320

Anomalous phase separation kinetics observed in a micelle system  

SciTech Connect

The authors report a real-time, two-dimensional light scattering study of the evolution of structure of a two component nonionic micelle system undergoing phase separation. The micelles act like molecular slug-a-beds whose domain growth is lethargic (i.e. slower than the cube root of time prediction for simple binary fluids). In fact, the growth kinetics can be empirically described as a stretched exponential approach to a pinned domain size. Although the kinetics are not yet understood, the anomalous behavior may be due to the ability of the spherical micelles to reorganize into more complex structures.

Wilcoxon, J.P.; Martin, J.E.

1995-01-01

321

Contactless magnetically levitated silicon wafer transport system  

Microsoft Academic Search

A new magnetically levitated wafer transport system is developed for the semiconductor fabrication process to get rid of the particle and oil contaminations that normally exist in conventional transport systems. The transport system consists of levitation, stabilization tracks, and a propelling system. Stabilities needed for levitation in the transport system are achieved by an antagonistic property produced in the tracks

K. H. Park; S. K. Lee; J. H. Yi; S. H. Kim; Y. K. Kwak; I. A. Wang

1996-01-01

322

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

323

Microfluidic Biosensing Systems Using Magnetic Nanoparticles  

PubMed Central

In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles.

Giouroudi, Ioanna; Keplinger, Franz

2013-01-01

324

Membrane separation systems: A research and development needs assessment. Executive summary: Volume 1.  

National Technical Information Service (NTIS)

Membrane based separation technology, a relative newcomer on the separations scene, has demonstrated the potential of saving enormous amounts of energy in the processing industries if substituted for conventional separation systems. Over 1 quad annually, ...

R. W. Baker E. L. Cussler W. Eykamp W. J. Koros R. L. Riley

1990-01-01

325

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

326

Statistical Treatment of Earth Observing System Pyroshock Separation Test Data  

NASA Technical Reports Server (NTRS)

The Earth Observing System (EOS) AM-1 spacecraft for NASA's Mission to Planet Earth is scheduled to be launched on an Atlas IIAS vehicle in June of 1998. One concern is that the instruments on the EOS spacecraft are sensitive to the shock-induced vibration produced when the spacecraft separates from the launch vehicle. By employing unique statistical analysis to the available ground test shock data, the NASA Lewis Research Center found that shock-induced vibrations would not be as great as the previously specified levels of Lockheed Martin. The EOS pyroshock separation testing, which was completed in 1997, produced a large quantity of accelerometer data to characterize the shock response levels at the launch vehicle/spacecraft interface. Thirteen pyroshock separation firings of the EOS and payload adapter configuration yielded 78 total measurements at the interface. The multiple firings were necessary to qualify the newly developed Lockheed Martin six-hardpoint separation system. Because of the unusually large amount of data acquired, Lewis developed a statistical methodology to predict the maximum expected shock levels at the interface between the EOS spacecraft and the launch vehicle. Then, this methodology, which is based on six shear plate accelerometer measurements per test firing at the spacecraft/launch vehicle interface, was used to determine the shock endurance specification for EOS. Each pyroshock separation test of the EOS spacecraft simulator produced its own set of interface accelerometer data. Probability distributions, histograms, the median, and higher order moments (skew and kurtosis) were analyzed. The data were found to be lognormally distributed, which is consistent with NASA pyroshock standards. Each set of lognormally transformed test data produced was analyzed to determine if the data should be combined statistically. Statistical testing of the data's standard deviations and means (F and t testing, respectively) determined if data sets were significantly different at a 95-percent confidence level. If two data sets were found to be significantly different, these families of data were not combined for statistical purposes. This methodology produced three separate statistical data families of shear plate data. For each population, a P99.1/50 (probability/confidence) per-separation-nut firing level was calculated. By using the binomial distribution, Lewis researchers determined that this pernut firing level was equivalent to a P95/50 per-flight confidence level. The overall envelope of the per-flight P95/50 levels led to Lewis' recommended EOS interface shock endurance specification. A similar methodology was used to develop Lewis' recommended EOS mission assurance levels. The available test data for the EOS mission are significantly larger than for a normal mission, thus increasing the confidence level in the calculated expected shock environment. Lewis significantly affected the EOS mission by properly employing statistical analysis to the data. This analysis prevented a costly requalification of the spacecraft's instruments, which otherwise would have been exposed to significantly higher test levels.

McNelis, Anne M.; Hughes, William O.

1998-01-01

327

A semi-automatic parachute separation system for balloon payloads  

NASA Astrophysics Data System (ADS)

At the National Scientific balloon Facility (NSBF), when operating stratospheric balloons with scientific payloads, the current practice for separating the payload from the parachute after descent requires the sending of commands, over a UHF uplink, from the chase airplane or the ground control site. While this generally works well, there have been occasions when, due to shadowing of the receive antenna or unfavorable aircraft attitude, the command has not been received and the parachute has failed to separate. In these circumstances the payload may be dragged for long distances before being recovered, with consequent danger of damage to expensive and sometimes irreplaceable scientific instrumentation. The NSBF has therefore proposed a system which would automatically separate the parachute without the necessity for commanding after touchdown. Such a system is now under development.. Mechanical automatic release systems have been tried in the past with only limited success. The current design uses an electronic system based on a tilt sensor which measures the angle that the suspension train subtends relative to the gravity vector. With the suspension vertical, there is minimum output from the sensor. When the payload touches down, the parachute tilts and in any tilt direction the sensor output increases until a predetermined threshold is reached. At this point, a threshold detector is activated which fires the pyrotechnic cutter to release the parachute. The threshold level is adjustable prior to the flight to enable the optimum tilt angle to be determined from flight experience. The system will not operate until armed by command. This command is sent during the descent when communication with the on-board systems is still normally reliable. A safety interlock is included to inhibit arming if the threshold is already high at the time the command is sent. While this is intended to be the primary system, the manual option would be retained as a back- up. A market survey was carried out to choose a suitable tilt sensor and three prototype systems were built for evaluation. These were installed in standard NSBF terminate units, and flown on routine operational flights throughout 2001 with the automatic pyrotechnic cutter active but off-line. A data logger was also installed to record system parameters during the descent phase. The results of these flights validated the system concept and it was found that the telemetry threshold monitor was also an asset to the operator in deciding when it was safe to send a manual parachute release command. However, the accumu lated test experience indicated that the originally- chosen tilt sensor, which uses a liquid electrolyte and requires an in-flight microprocessor, was not sufficiently rugged or reliable. A solid-state accelerometer, with encapsulated analog signal processing, was therefore selected as a replacement and the threshold electronics redesigned to match this sensor. This system is currently being evaluated on NSBF operation al flights during 2002. On completion of this phase, NASA will review the results and a decision will be made whether to use this design as the primary operational system on future flights. This paper discusses the requirements for such a system and describes the current design in detail. It reports on the evaluation flights of 2001 and 2002 and their results to date.

Farman, M.

328

Improved neutron monitor systems for Savannah River Site separations facilities  

SciTech Connect

The Savannah River Laboratory (SRL), in conjunction with Savannah River Site (SRS) Separations Technology personnel, has developed and implemented a comprehensive program to improve the performance and reliability of neutron detector systems (neutron monitors) in the SRS separations areas. The neutron monitors, which monitor the buildup of fissile material in the mixer-settler banks of the solvent extraction process, are important nuclear safety control devices. A review of the performance history of the neutron monitors reveals that many of the systems exhibit problems arising from several causes, including: low neutron sensitivity, high susceptibility to electromagnetic interferences (due to long cable runs between detectors and their electronics), and high maintenance requirements. To address these problems, the neutron monitor improvement program encompasses both technical and administrative improvements, including: substitution of more sensitive neutron monitors at many locations in the solvent extraction areas, the development of an integrated preamplifier/amplifier package to eliminate long cable runs, and improvements in the neutron monitor functional test procedures to reduce maintenance requirements. The implementation of these improvements, already partially complete, is expected to provide enhanced operation and reliability for the neutron monitors. This paper will present a description of the solvent neutron monitors as well as technical details of the improvement program. 2 refs., 5 figs., 1 tab.

Griffin, J.C.

1989-01-01

329

Magnetic suspension and balance system study  

NASA Technical Reports Server (NTRS)

A compact design for a superconducting magnetic suspension and balance system is developed for a 8 ft. x 8 ft. transonic wind tunnel. The main features of the design are: a compact superconducting solenoid in the suspended airplane model; permanent magnet wings; one common liquid helium dewar for all superconducting coils; efficient new race track coils for roll torques; use of established 11 kA cryostable AC conductor; acceptable AC losses during 10 Hz control even with all steel structure; and a 560 liter/hour helium liquefier. Considerable design simplicity, reduced magnet weights, and reduced heat leak results from using one common dewar which eliminates most heavy steel structure between coils and the suspended model. Operational availability is thought to approach 100% for such magnet systems. The weight and cost of the magnet system is approximately one-third that of previous less compact designs.

Boom, R. W.; Eyssa, Y. M.; Mcintosh, G. E.; Abdelsalam, M. K.

1984-01-01

330

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

331

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.

332

Synchronization of magnetic stars in binary systems  

NASA Technical Reports Server (NTRS)

Asynchronous rotation of magnetic stars in close binary systems drives substantial field-aligned electrical currents between the magnetic star and its companion. The resulting magnetohydrodynamic torque is able to account for the heretofore unexplained synchronous rotation of the strongly magnetic degenerate dwarf component in systems like AM Her, VV Pup, AN UMa, and EF Eri as well as the magnetic A type component in systems like HD 98088 and 41 Tauri. The electric fields produced by even a small asynchronism are large and may accelerate some electrons to high energies, producing radio emission. The total energy dissipation rate in systems with degenerate dwarf spin periods as short as 1 minute may reach 10 to the 33rd ergs/s. Total luminosities of this order may be a characteristic feature of such systems.

Lamb, F. K.; Aly, J.-J.; Cook, M. C.; Lamb, D. Q.

1983-01-01

333

Combined air stripper/membrane vapor separation systems. Final report  

SciTech Connect

Air stripping is an economical and efficient method of removing dissolved volatile organic compounds (VOCs) from contaminated groundwater. Air strippers, however, produce a vent air stream, which must meet the local air quality limits. If the VOC content exceeds the limits, direct discharge is not possible; therefore, a carbon adsorption VOC capture system is used to treat the vent air. This treatment step adds a cost of at least $50/lb of VOC captured. In this program, a combined air stripper/membrane vapor separation system was constructed and demonstrated in the laboratory. The membrane system captures VOCs from the stripper vent stream at a projected cost of $15/lb VOC for a water VOC content of 5 ppmw, and $75/lb VOC for a water VOC content of 1 ppmw. The VOCs are recovered as a small, concentrated liquid fraction for disposal or solvent recycling. The concept has been demonstrated in experiments with a system capable of handling up to 150,000 gpd of water. The existing demonstration system is available for field tests at a DOE facility or remediation site. Replacement of the current short air stripping tower (effective height 3 m) with a taller tower is recommended to improve VOC removal.

Wijmans, J.G.; Baker, R.W.; Kamaruddin, H.D.; Kaschemekat, J.; Olsen, R.P.; Rose, M.E.; Segelke, S.V.

1992-11-01

334

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

335

a Uhv Compatible SQUID Magnetometer System for Investigations in Surface, Interface, and Thin Film Magnetism  

Microsoft Academic Search

The magnetic properties of Co thin films on silicon and magnetite single crystal substrates grown by electron beam evaporation were studied in situ in UHV using a superconducting quantum interference device magnetometer (UHVSQM). In this system, freshly deposited thin film samples from a separate molecular beam epitaxy (MBE) facility, were transported into the UHVSQM for magnetic characterization without breaking vacuum.

Stefano Spagna

1995-01-01

336

An autonomous surveillance system for blind sources localization and separation  

NASA Astrophysics Data System (ADS)

This paper aims at developing a new technology that will enable one to conduct an autonomous and silent surveillance to monitor sound sources stationary or moving in 3D space and a blind separation of target acoustic signals. The underlying principle of this technology is a hybrid approach that uses: 1) passive sonic detection and ranging method that consists of iterative triangulation and redundant checking to locate the Cartesian coordinates of arbitrary sound sources in 3D space, 2) advanced signal processing to sanitizing the measured data and enhance signal to noise ratio, and 3) short-time source localization and separation to extract the target acoustic signals from the directly measured mixed ones. A prototype based on this technology has been developed and its hardware includes six B and K 1/4-in condenser microphones, Type 4935, two 4-channel data acquisition units, Type NI-9234, with a maximum sampling rate of 51.2kS/s per channel, one NI-cDAQ 9174 chassis, a thermometer to measure the air temperature, a camera to view the relative positions of located sources, and a laptop to control data acquisition and post processing. Test results for locating arbitrary sound sources emitting continuous, random, impulsive, and transient signals, and blind separation of signals in various non-ideal environments is presented. This system is invisible to any anti-surveillance device since it uses the acoustic signal emitted by a target source. It can be mounted on a robot or an unmanned vehicle to perform various covert operations, including intelligence gathering in an open or a confined field, or to carry out the rescue mission to search people trapped inside ruins or buried under wreckages.

Wu, Sean; Kulkarni, Raghavendra; Duraiswamy, Srikanth

2013-05-01

337

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

338

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

339

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

340

An SLF magnetic antenna calibration system  

NASA Astrophysics Data System (ADS)

Calibrating the super low frequency (SLF) magnetic antenna in magnetic free space or an outdoor environment is difficult and complicated due to the large size calibration instruments and lots of measurement times. Aiming to calibrate the SLF magnetic antenna simply and efficiently, a calibration system comprised of a multi-frequency source, an AC constant-current source and a solenoid is proposed according to the characteristic of an SLF magnetic antenna. The static magnetic transfer coefficient of the designed solenoid is calibrated. The measurement of the frequency response characteristics suggests the transfer coefficient remains unchanged in the range of the SLF band and is unaffected by the magnetic antenna internally installed. The CORDIC algorithm implemented in an FPGA is realized to generate a linear evenly-spaced multi-frequency signal with equal energy at each frequency. An AC constant weak current source circuit is designed in order to avoid the impact on the magnetic induction intensity of a calibration system affected by impedance variation when frequency changing, linearity and the precision of the source are measured. The frequency characteristic of a magnetic antenna calibrated by the proposed calibration system agrees with the theoretical result and the standard Glass ring calibration result. The calibration precision satisfies the experimental requirement.

Shimin, Feng; Suihua, Zhou; Zhiyi, Chen; Hongxin, Zhang

2014-05-01

341

Compounds for expanding the descriptor space for characterizing separation systems.  

PubMed

A combination of gas chromatography and liquid-liquid partitions in totally organic biphasic systems is used to determine descriptor values for compounds of low volatility suitable for characterizing open tubular columns at high temperatures. The descriptor database of varied compounds includes several difficult to determine by conventional techniques due to their low water solubility or stability. The descriptor database facilitates an expansion of the descriptor space and compound variation for characterizing separation systems. As an application the descriptor database is used to determine the system constants for SPB-Octyl, HP-5, Rxi-5Sil MS, Rtx-440, and Rtx-OPP for the temperature range 200-300°C. As an example of the broader affect of temperature on column selectivity the variation of the system constants for Rtx-440 over the temperature range 60-300°C is described in detail. These studies demonstrate the persistence of polar interactions to the highest temperature studied and that at high temperatures selectivity differences persist for moderately polar stationary phases. PMID:23089515

Karunasekara, Thushara; Poole, Colin F

2012-11-30

342

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

343

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

344

Magnetic Tracking System: Monitoring Heart Valve Prostheses  

Microsoft Academic Search

A magnetic tracking system for monitoring the performance and activity of mechanical heart valve prostheses has been developed. Physicians may find the system valuable in detecting thrombosis (blood clots), scar tissue, or other complications that may indicate life-threatening medical conditions, such as heart attacks, strokes, or aneurysms. In this paper, a disk-shaped NdFeB magnet comparable in size to the floating

Jeremy A. Baldoni; Benjamin B. Yellen

2007-01-01

345

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

346

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

347

Prototypes of Holding Magnet System  

Microsoft Academic Search

New experiments have been proposed with the 4-pi JLab CLAS detector and a Frozen Spin Polarized Target located at the center of the detector. In such experiments, the target will be polarized outside the detector by a high field (5.0 Tesla) magnet at T=0.5 K. Afterwards another \\

Nicolas Recalde; Oleksandr Dzyubak; Christopher Keith; Mikell Seely

2003-01-01

348

Ion optics system incorporating radio frequency mass separation  

NASA Technical Reports Server (NTRS)

Results of an experimental study are presented. They show that an RF mass discriminator, based on a Bennett mass spectrometer concept, can be used to discriminate between two species of ions with about a 2-to-1 charge-to-mass ratio. Such a device would be useful for separating monatomic and diatomic oxygen ions in a system designed to simulate the environment that spacecraft encounter in low earth orbit. The influence of changing mass discriminator parameters - such as the spacing of its grids, the amplitude and frequency of RF voltage signals applied to it and the current density of ions incident upon it - on its species discrimination capabilities is discussed. Experimental results are also compared to the results of a simple theoretical model to gain insight into the processes occurring in the discriminator. These results are shown to be in good agreement.

Anderson, John R.; Carruth, M. R., Jr.

1990-01-01

349

Multiparameter magnetic inspection system with magnetic field control and plural magnetic transducers  

DOEpatents

A multiparameter magnetic inspection system is disclosed for providing an efficient and economical way to derive a plurality of independent measurements regarding magnetic properties of the magnetic material under investigation. The plurality of transducers for a plurality of different types of measurements operatively connected to the specimen. The transducers are in turn connected to analytical circuits for converting transducer signals to meaningful measurement signals of the magnetic properties of the specimen. The measurement signals are processed and can be simultaneously communicated to a control component. The measurement signals can also be selectively plotted against one another. The control component operates the functioning of the analytical circuits and operates and controls components to impose magnetic fields of desired characteristics upon the specimen. The system therefore allows contemporaneous or simultaneous derivation of the plurality of different independent magnetic properties of the material which can then be processed to derive characteristics of the material. 1 figure.

Jiles, D.C.

1991-04-16

350

Multiparameter magnetic inspection system with magnetic field control and plural magnetic transducers  

DOEpatents

A multiparameter magnetic inspection system for providing an efficient and economical way to derive a plurality of independent measurements regarding magnetic properties of the magnetic material under investigation. The plurality of transducers for a plurality of different types of measurements operatively connected to the specimen. The transducers are in turn connected to analytical circuits for converting transducer signals to meaningful measurement signals of the magnetic properties of the specimen. The measurement signals are processed and can be simultaneously communicated to a control component. The measurement signals can also be selectively plotted against one another. The control component operates the functioning of the analytical circuits and operates and controls components to impose magnetic fields of desired characteristics upon the specimen. The system therefore allows contemporaneous or simultaneous derivation of the plurality of different independent magnetic properties of the material which can then be processed to derive characteristics of the material.

Jiles, David C. (Ames, IA)

1991-04-16

351

Polymerase chain reaction system using magnetic beads for analyzing a sample that includes nucleic acid  

DOEpatents

A polymerase chain reaction system for analyzing a sample containing nucleic acid includes providing magnetic beads; providing a flow channel having a polymerase chain reaction chamber, a pre polymerase chain reaction magnet position adjacent the polymerase chain reaction chamber, and a post pre polymerase magnet position adjacent the polymerase chain reaction chamber. The nucleic acid is bound to the magnetic beads. The magnetic beads with the nucleic acid flow to the pre polymerase chain reaction magnet position in the flow channel. The magnetic beads and the nucleic acid are washed with ethanol. The nucleic acid in the polymerase chain reaction chamber is amplified. The magnetic beads and the nucleic acid are separated into a waste stream containing the magnetic beads and a post polymerase chain reaction mix containing the nucleic acid. The reaction mix containing the nucleic acid flows to an analysis unit in the channel for analysis.

Nasarabadi, Shanavaz (Livermore, CA)

2011-01-11

352

Coolant quality for magnetic resonance imaging systems  

Microsoft Academic Search

As radiologists demand increased power, speed and duty cycle from their magnetic resonance imaging (MRI) systems, thermal management of the gradient sub-system becomes more challenging. A heat exchanger in the MRI system cools heat-generating components by pumping water through hollow copper tubing, which also carries high electrical currents. Water is used as a coolant because of its high specific heat

Julie Wong; Garron K Morris

2008-01-01

353

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

354

Magnetic Launch Assist System-Artist's Concept  

NASA Technical Reports Server (NTRS)

This illustration is an artist's concept of a Magnetic Launch Assist System, formerly referred as the Magnetic Levitation (Maglev) system, for space launch. Overcoming the grip of Earth's gravity is a supreme challenge for engineers who design rockets that leave the planet. Engineers at the Marshall Space Flight Center have developed and tested Magnetic Launch Assist System technologies that could levitate and accelerate a launch vehicle along a track at high speeds before it leaves the ground. Using electricity and magnetic fields, a Magnetic Launch Assist system would drive a spacecraft along a horizontal track until it reaches desired speeds. A full-scale, operational track would be about 1.5-miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, landing gear and the wing size, as well as the elimination of propellant weight resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

1999-01-01

355

DOE/Simplec magnetic susceptibility logging system  

SciTech Connect

A magnetic susceptibility logging system has been developed which is relatively stable under normal field logging conditions and which produces logs that accurately represent in situ variations in magnetic susceptibility. However, both field and laboratory tests indicate the need for further improvement of temperature stabilization and bridge compensation; a new generation system designed by Simplec may fill that need. A cubic granite block with a magnetic susceptibility of 385 ..mu..CGS is designated as the primary calibration standard and is available for public use at the DOE facility in Grand Junction, Colorado. Models are also available for characterization of magnetic susceptibility systems. These include models to provide borehole size correction factors, thin layer interpretation parameters, reproducibility limits, longitudinal resolution, and radius of investigation. The DOE/Simplec system has a 99-percent radius of investigation, approximately equal to the coil length (15 inches), and a 99-percent thickness of investigation, approximately equal to two coil lengths. The true magnetic susceptibility and thickness of isolated layers less than two coil lengths in thickness can be obtained through use of parameters measured from their log responses. Field tests show that the system has a reproducibility of at least 5 ..mu..CGS and that logging at 25 ft/min is a good compromise between speed of operation and keeping the probe on the sidewall. Comparison of log and core magnetic susceptibility measurements confirms the fact that the logging system samples a rather large volume and that interpretive aids are necessary to unfold the true variation of magnetic susceptibility with depth. Finally, logs from known uranium-favorable environments show that magnetic susceptibility measurements can give an indication of the degree of geochemical alteration, which is one of the uranium-favorable haloes sought by exploration geologists.

Emilia, D.A.; Allen, J.W.; Chessmore, R.B.; Wilson, R.B.

1981-03-01

356

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

357

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

358

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

359

Identification of active magnetic bearing system with a flexible rotor  

NASA Astrophysics Data System (ADS)

Active magnetic bearings (AMBs) are widely applied in high-speed rotating machinery, especially in special environments. In designing and adjusting an AMB system, the mathematical model of the system plays an important role. Identification is a useful method to obtain the models of AMB systems. This paper concentrates on identification method for an AMB system with a flexible rotor. Based on the theoretical system model and the measured frequency-response model, the proposed method estimates the unknown parameters and establishes the transfer function matrix model of the AMB system. According to the theoretical model, this paper decomposes the identification procedure into a few steps and the model is sequentially reduced by these steps. In this procedure, the submodels are identified separately and finally combined together. The proposed method is validated by experiments on three AMB systems.

Sun, Zhe; He, Ying; Zhao, Jingjing; Shi, Zhengang; Zhao, Lei; Yu, Suyuan

2014-12-01

360

Dynamically stable magnetic suspension/bearing system  

DOEpatents

A magnetic bearing system contains magnetic subsystems which act together to support a rotating element in a state of dynamic equilibrium. However, owing to the limitations imposed by Earnshaw's Theorem, the magnetic bearing systems to be described do not possess a stable equilibrium at zero rotational speed. Therefore, mechanical stabilizers are provided, in each case, to hold the suspended system in equilibrium until its speed has exceeded a low critical speed where dynamic effects take over, permitting the achievement of a stable equilibrium for the rotating object. A state of stable equilibrium is achieved above a critical speed by use of a collection of passive elements using permanent magnets to provide their magnetomotive excitation. The magnetic forces exerted by these elements, when taken together, levitate the rotating object in equilibrium against external forces, such as the force of gravity or forces arising from accelerations. At the same time, this equilibrium is made stable against displacements of the rotating object from its equilibrium position by using combinations of elements that possess force derivatives of such magnitudes and signs that they can satisfy the conditions required for a rotating body to be stably supported by a magnetic bearing system over a finite range of those displacements.

Post, Richard F. (Walnut Creek, CA)

1996-01-01

361

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

362

Magnetic Field Response Measurement Acquisition System  

NASA Technical Reports Server (NTRS)

A measurement acquisition method that alleviates many shortcomings of traditional measurement systems is presented in this paper. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed.

Woodard, Stanley E.; Taylor, Bryant D.; Shams, Qamar A.; Fox, Robert L.

2005-01-01

363

Permanent-magnet-less synchronous reluctance system  

DOEpatents

A permanent magnet-less synchronous system includes a stator that generates a magnetic revolving field when sourced by an alternating current. An uncluttered rotor is disposed within the magnetic revolving field and spaced apart from the stator to form an air gap relative to an axis of rotation. The rotor includes a plurality of rotor pole stacks having an inner periphery biased by single polarity of a north-pole field and a south-pole field, respectively. The outer periphery of each of the rotor pole stacks are biased by an alternating polarity.

Hsu, John S

2012-09-11

364

Magnetically Coupled Adjustable Speed Drive Systems  

SciTech Connect

Adjustable speed drive (ASD) technologies have the ability to precisely control motor sytems output and produce a numbr of benefits including energy and demand savings. This report examines the performance and cost effectiveness of a specific class of ASDs called magnetically-coupled adjustable speed drives (MC-ASD) which use the strength of a magnetic field to control the amount of torque transferred between motor and drive shaft. The MagnaDrive Adjustable Speed Coupling System uses fixed rare-earth magnets and varies the distance between rotating plates in the assembly. the PAYBACK Variable Speed Drive uses an electromagnet to control the speed of the drive

Chvala, William D.; Winiarski, David W.

2002-08-18

365

Systems and methods for separating a multiphase fluid  

NASA Technical Reports Server (NTRS)

Apparatus and methods for separating a fluid are provided. The apparatus can include a separator and a collector having an internal volume defined at least in part by one or more surfaces narrowing toward a bottom portion of the volume. The separator can include an exit port oriented toward the bottom portion of the volume. The internal volume can receive a fluid expelled from the separator into a flow path in the collector and the flow path can include at least two directional transitions within the collector.

Weislogel, Mark M. (Inventor); Thomas, Evan A. (Inventor); Graf, John C. (Inventor)

2011-01-01

366

Fuel cell system with separating structure bonded to electrolyte  

DOEpatents

A fuel cell assembly comprises a separating structure configured for separating a first reactant and a second reactant wherein the separating structure has an opening therein. The fuel cell assembly further comprises a fuel cell comprising a first electrode, a second electrode, and an electrolyte interposed between the first and second electrodes, and a passage configured to introduce the second reactant to the second electrode. The electrolyte is bonded to the separating structure with the first electrode being situated within the opening, and the second electrode being situated within the passage.

Bourgeois, Richard Scott (Albany, NY); Gudlavalleti, Sauri (Albany, NY); Quek, Shu Ching (Clifton Park, NY); Hasz, Wayne Charles (Pownal, VT); Powers, James Daniel (Santa Monica, CA)

2010-09-28

367

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

368

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

369

Wide gap, permanent magnet biased magnetic bearing system  

NASA Astrophysics Data System (ADS)

The unique features and applications of the presented electrical permanent magnetic bearing system essentially result from three facts: (1) the only bearing rotor components are nonlaminated ferromagnetic steel collars or cylinders; (2) all radial and axial forces are transmitted via radial gaps; and (3) large radial bearing gaps can be provided with minimum electric power consumption. The large gaps allow for effective encapsulation and shielding of the rotors at elevated or low temperatures, corrosive or ultra clean atmosphere or vacuum or high pressure environment. Two significant applications are described: (1) a magnetically suspended x ray rotary anode was operated under high vacuum conditions at 100 KV anode potential, 600 C temperature at the rotor collars and speed 18000 rpm with 13 mm radial bearing gap; and (2) an improved Czochralski type crystal growth apparatus using the hot wall method for pulling GaAs single crystals of low dislocation density. Both crystal and crucible are carried and transported by magnetically suspended shafts inside a hermetically sealed housing at 800 C shaft and wall temperature. The radial magnetic bearing gap measures 24 mm.

Boden, Karl

1992-05-01

370

Large-gap magnetic suspension systems  

NASA Technical Reports Server (NTRS)

The classification of magnetic suspension devices into small-gap and large-gap categories is addressed. The relative problems of position sensing, control systems, power supplies, electromagnets, and magnetic field or force analysis are discussed. The similarity of all systems from a controls standpoint is qualified. Some applications where large-gap technology is being applied to systems with a physically small air-gap are mentioned. Finally, the applicability of some other suspension approaches, such as electrodynamic or superconducting are briefly addressed.

Britcher, Colin P.

1992-01-01

371

Knolle Magnetrans: A magnetically levitated train system  

NASA Technical Reports Server (NTRS)

The Knolle Magnetrans is a continuous transportation system featuring small cars traveling in rapid succession, levitated by permanent magnets in repulsion, and propelled by stationary linear induction motors. The vehicles' headway, speed, acceleration, and deceleration are designed into the system and mechanically enforced. Passengers board dynamically and controls consist of a simple on-off relay. This paper summarizes the system design goals, describes the system components and discusses related environmental issues.

Knolle, Ernst G.

1992-01-01

372

Knolle Magnetrans: A magnetically levitated train system  

NASA Astrophysics Data System (ADS)

The Knolle Magnetrans is a continuous transportation system featuring small cars traveling in rapid succession, levitated by permanent magnets in repulsion, and propelled by stationary linear induction motors. The vehicles' headway, speed, acceleration, and deceleration are designed into the system and mechanically enforced. Passengers board dynamically and controls consist of a simple on-off relay. This paper summarizes the system design goals, describes the system components and discusses related environmental issues.

Knolle, Ernst G.

1992-05-01

373

Optimal design of hybrid magnet in maglev system with both permanent and electro magnets  

SciTech Connect

A magnetic levitation system with both permanent magnets and electromagnets has less power loss than a conventional attractive-type system. In this paper, the authors propose an analysis procedure of the hybrid magnet in the experimental levitation system. First, they make a two-dimensional analysis of the hybrid magnet. Though the vector potential A method is often adopted to solve magnetic problems, they propose the magnetic field intensity H method. Second, utilizing the sequential quadratic programming method, they attempt to optimize the arrangement of permanent magnets, which have the maximum guidance force. Finally, they investigate the responses of the experimental magnet levitation system by simulations.

Onuki, Takashi; Toda, Yasushi (Waseda Univ., Tokyo (Japan))

1993-03-01

374

Dynamic analysis of a magnetic bearing system with flux control  

NASA Technical Reports Server (NTRS)

Using measured values of two-dimensional forces in a magnetic actuator, equations of motion for an active magnetic bearing are presented. The presence of geometric coupling between coordinate directions causes the equations of motion to be nonlinear. Two methods are used to examine the unbalance response of the system: simulation by direct integration in time; and determination of approximate steady state solutions by harmonic balance. For relatively large values of the derivative control coefficient, the system behaves in an essentially linear manner, but for lower values of this parameter, or for higher values of the coupling coefficient, the response shows a split of amplitudes in the two principal directions. This bifurcation is sensitive to initial conditions. The harmonic balance solution shows that the separation of amplitudes actually corresponds to a change in stability of multiple coexisting solutions.

Knight, Josiah; Walsh, Thomas; Virgin, Lawrence

1994-01-01

375

Temperature-induced phenomena in systems of magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticle ensembles have received a lot of attention, stemming in part from their current and potential applications in biomedicine and in the development of high-density magnetic storage media. Key to the functionality of these systems are microscopic structures and mechanisms that make them exhibit unique properties and behave differently from their bulk counterparts. We studied microscopic structures and processes that dictate macroscopic properties, behavior and functionality of magnetic nanoparticle ensembles. As the temperature T strongly influences the magnetic behavior of these systems, we studied temperature dependent magnetic properties using AC-susceptibility and DC-magnetization measurements carried out over a broad range of temperatures, between 3 and 300 K. We extracted structural information from X-ray diffraction (XRD) and direct imaging techniques and correlate it with magnetic properties, in an attempt at better understanding the microscopic structures and magnetic mechanisms responsible for the macroscopic magnetic behavior. We studied ensembles of magnetic nanoparticles: nickel ferrite immobilized in a solid matrix and cobalt ferrite immersed in carrier fluid respectively, in order to explore their potential use in biomedical applications and magnetic recording. For both NiFe2O4(NFO) and Co0.2Fe2.8O4 (CFO) relaxation mechanisms were determined. Structural properties and average particle sizes were derived from XRD, including synchrotron XRD, and direct imaging techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Temperature dependent magnetic measurements, FC-ZFC DC magnetometry, as well as AC complex susceptibility measurements at frequencies between 10 and 10,000 Hz were carried out within the temperature range 3Kmagnetization and AC susceptibility measurements were performed using a Physical Property Measurement System (PPMS), which allows measurements in magnetic fields up to 9T and within a temperature range between 2 and 350 K. For NFO, besides the expected blocking of the superspin, observed at T1 ? 45 K, we found that the system undergoes a magnetic transition at T2 ? 6 K. For the latter, frequency- and temperature-resolved dynamic susceptibility data reveal characteristics that are unambiguously related to collective spin freezing: the relative variation (per frequency decade) of the in-phase-susceptibility peak temperature is ˜0.025, critical dynamics analysis yields an exponent zv = 9.6 and a zero-field freezing temperature TF = 5.8 K, and, in a magnetic field, TF (H) is excellently described by the de Almeida-Thouless line deltaT F infinity H2/3. Moreover, out-of-phase-susceptibility vs. temperature datasets collected at different frequencies collapse on a universal dynamic scaling curve. All these observations indicate the existence of a spin-glass-like surface layer that surrounds the superparamagnetic core and undergoes a transition to a frozen state upon cooling below 5.8 K. For the CFO ferrofluid, we used temperature- and frequency-resolved AC-susceptibility measurements to investigate its magnetic relaxation above the freezing point of the liquid carrier. Our data show that both the Neel and the Brown relaxation mechanisms are operative at temperatures in the vicinity of the out-of-phase (imaginary) susceptibility peak. We separate the contributions of the two mechanisms to the overall-relaxation time, and demonstrate that Brownian relaxation plays a dominant role at all temperatures within this high-dissipation regime.

Bhuiya, Abdul Wazed

376

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...

377

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

378

Light scattering investigation of phase separation in a micelle system  

SciTech Connect

We report a real-time, two-dimensional light scattering study of the evolution of structure in a two component nonionic micelle system during phase separation via spinodal decomposition. Our principal finding is that domain growth proceeds much slower than the cube root of time prediction for simple binary fluids. In fact, the growth kinetics can be empirically described as a stretched exponential approach to a pinned domain size. Although the kinetics are not yet understood, this anomalous behavior may be due to the ability of the spherical micelles to reorganize into more complex structures. The domain structure also shows some anomalies. Although at short times the expected structure factor for a critical quench is observed, at long times the structure factor crosses over to the off-critical form. However, in all cases the average scattered intensity is proportional to the cube of the domain size. These findings are discussed in comparison to standard theories of and experimental work on binary fluids.

Wilcoxon, J.P.; Martin, J.E.; Odinek, J.

1993-12-31

379

The Effect of Stress on the Susceptibility and Magnetization of a Partially Magnetized Multidomain System  

Microsoft Academic Search

An analysis of the effects of directed stress on magnetization and susceptibility is presented, with special attention to the problems of rock magnetism. A model is proposed for partial magnetization of an isotropic multidomain magnetic system. The behavior of the model system in response to applied stress is analyzed. It is found that the response of the system to applied

John W. Kern

1961-01-01

380

Progress of magnetic suspension systems and magnetic bearings in the USSR  

NASA Technical Reports Server (NTRS)

This paper traces the development and progress of magnetic suspension systems and magnetic bearings in the USSR. The paper describes magnetic bearings for turbomachines, magnetic suspension systems for vibration isolation, some special measuring devices, wind tunnels, and other applications. The design, principles of operation, and dynamic characteristics of the system are presented.

Kuzin, A. V.

1992-01-01

381

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

382

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

383

A new MAGLEV system for magnetically levitated carrier system  

Microsoft Academic Search

A power-saving electromagnetic suspension system has been developed in which electromagnets with permanent magnets are used to suspend the vehicle. The electromagnets are controlled to maintain air gap length so that the attractive force by the permanent magnet always balances the total weight of the vehicle and its loads, based on modern control theory. This technology realizes a significantly power-saving

Mimpei Morishita; Teruo Azukizawa; Shuji Kanda; Noburu Tamura; Toyohiko Yokoyama

1989-01-01

384

Computational analysis of enhanced magnetic bioseparation in microfluidic systems with flow-invasive magnetic elements.  

PubMed

A microfluidic design is proposed for realizing greatly enhanced separation of magnetically-labeled bioparticles using integrated soft-magnetic elements. The elements are fixed and intersect the carrier fluid (flow-invasive) with their length transverse to the flow. They are magnetized using a bias field to produce a particle capture force. Multiple stair-step elements are used to provide efficient capture throughout the entire flow channel. This is in contrast to conventional systems wherein the elements are integrated into the walls of the channel, which restricts efficient capture to limited regions of the channel due to the short range nature of the magnetic force. This severely limits the channel size and hence throughput. Flow-invasive elements overcome this limitation and enable microfluidic bioseparation systems with superior scalability. This enhanced functionality is quantified for the first time using a computational model that accounts for the dominant mechanisms of particle transport including fully-coupled particle-fluid momentum transfer. PMID:24931437

Khashan, S A; Alazzam, A; Furlani, E P

2014-01-01

385

Timing Recovery Strategies in Magnetic Recording Systems  

NASA Astrophysics Data System (ADS)

At some point in a digital communications receiver, the received analog signal must be sampled. Good performance requires that these samples be taken at the right times. The process of synchronizing the sampler with the received analog waveform is known as timing recovery. Conventional timing recovery techniques perform well only when operating at high signal-to-noise ratio (SNR). Nonetheless, iterative error-control codes allow reliable communication at very low SNR, where conventional techniques fail. This paper provides a detailed review on the timing recovery strategies based on per-survivor processing (PSP) that are capable of working at low SNR. We also investigate their performance in magnetic recording systems because magnetic recording is a primary method of storage for a variety of applications, including desktop, mobile, and server systems. Results indicate that the timing recovery strategies based on PSP perform better than the conventional ones and are thus worth being employed in magnetic recording systems.

Kovintavewat, Piya

386

Magnetic Field Response Measurement Acquisition System  

NASA Technical Reports Server (NTRS)

Magnetic field response sensors designed as passive inductor-capacitor circuits produce magnetic field responses whose harmonic frequencies correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induction. A radio frequency antenna produces the time varying magnetic field used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for discerning changes in sensor s response kequency, resistance and amplitude is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminating the need to have a data acquisition channel dedicated to each sensor. The method does not require the sensors to be in proximity to any form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

Woodard, Stanley E. (Inventor); Taylor, Bryant D. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, Christopher L. (Inventor); Fox, Melanie L. (Inventor); Bryant, Robert G. (Inventor)

2006-01-01

387

Magnetic Field Response Measurement Acquisition System  

NASA Technical Reports Server (NTRS)

Magnetic field response sensors designed as passive inductor- capacit or circuits produce magnetic field responses whose harmonic frequenci es correspond to states of physical properties for which the sensors measure. Power to the sensing element is acquired using Faraday induc tion. A radio frequency antenna produces the time varying magnetic fi eld used for powering the sensor, as well as receiving the magnetic field response of the sensor. An interrogation architecture for disce rning changes in sensor's response frequency, resistance and amplitud e is integral to the method thus enabling a variety of measurements. Multiple sensors can be interrogated using this method, thus eliminat ing the need to have a data acquisition channel dedicated to each se nsor. The method does not require the sensors to be in proximity to a ny form of acquisition hardware. A vast array of sensors can be used as interchangeable parts in an overall sensing system.

Woodward, Stanley E. (Inventor); Taylor, Bryant D. (Inventor)

2007-01-01

388

Soundprism: An Online System for Score-Informed Source Separation of Music Audio  

Microsoft Academic Search

Soundprism, as proposed in this paper, is a computer system that separates single-channel polyphonic music audio played by harmonic sources into source signals in an online fashion. It uses a musical score to guide the separation process. To the best of our knowledge, this is the first online system that addresses score-informed music source separation that can be made into

Zhiyao Duan; Bryan Pardo

2011-01-01

389

Broadband antenna systems for lightning magnetic fields  

NASA Technical Reports Server (NTRS)

Broadband magnetic antenna systems suitable for recording submicrosecond field changes are described, and typical data from distant lightning are presented. Two types of systems are described, one with a high-impedance antenna loop connected to the integrator by a twisted pair of coaxial cables and another with the antenna loop and twisted signal loops formed from a single piece of coaxial cable. Data for correlated magnetic and electric field waveforms from lightning at a distance of 50 to 100 km are presented and are shown to be almost identical.

Krider, E. P.; Noggle, R. C.

1975-01-01

390

Permanent magnetic system design for the wall-climbing robot  

Microsoft Academic Search

This paper presents the design of the permanent magnetic system for the wall climbing robot with permanent magnetic tracks. A proposed wall climbing robot with permanent magnetic adhesion mechanism for inspecting the oil tanks is briefly put forward, including the mechanical system architecture. The permanent magnetic adhesion mechanism and the tracked locomotion mechanism are employed in the robot system. By

Weimin Shen; Jason Gu; Yanjun Shen

2005-01-01

391

Magnetic Field Response Measurement Acquisition System  

NASA Technical Reports Server (NTRS)

This paper presents a measurement acquisition method that alleviates many shortcomings of traditional measurement systems. The shortcomings are a finite number of measurement channels, weight penalty associated with measurements, electrical arcing, wire degradations due to wear or chemical decay and the logistics needed to add new sensors. Wire degradation has resulted in aircraft fatalities and critical space launches being delayed. The key to this method is the use of sensors designed as passive inductor-capacitor circuits that produce magnetic field responses. The response attributes correspond to states of physical properties for which the sensors measure. Power is wirelessly provided to the sensing element by using Faraday induction. A radio frequency antenna produces a time-varying magnetic field used to power the sensor and receive the magnetic field response of the sensor. An interrogation system for discerning changes in the sensor response frequency, resistance and amplitude has been developed and is presented herein. Multiple sensors can be interrogated using this method. The method eliminates the need for a data acquisition channel dedicated to each sensor. The method does not require the sensors to be near the acquisition hardware. Methods of developing magnetic field response sensors and the influence of key parameters on measurement acquisition are discussed. Examples of magnetic field response sensors and the respective measurement characterizations are presented. Implementation of this method on an aerospace system is discussed.

Woodard, Stanley E.; Taylor,Bryant D.; Shams, Qamar A.; Fox, Robert L.

2007-01-01

392

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

393

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

394

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

395

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

396

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

397

Enhancement of the efficiency of magnetic targeting for drug delivery: Development and evaluation of magnet system  

NASA Astrophysics Data System (ADS)

Deep magnetic capture and clinical application are the current trends for magnetic targeted drug delivery system. More promising and possible strategies are needed to overcome the current limitations and further improve the magnetic targeting technique. Recent advances in the development of targeting magnet system show promise in progressing this technology from the laboratory to the clinic. Starting from well-known basic concepts, current limitations of magnetic targeted drug delivery system are analyzed. Meanwhile, the design concepts and evaluations of some effective improvements in magnet system are discussed and reviewed with reference to (i) reasonable design of magnet system; (ii) control modes of magnet system used to generate dynamical magnetic fields; and (iii) magnetic field driving types.

Cao, Quanliang; Han, Xiaotao; Li, Liang

2011-08-01

398

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

399

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

400

Magnetic phase separation-induced coercivity enhancement in epitaxial Nd0.5Sr0.5CoO3 films  

NASA Astrophysics Data System (ADS)

Interfacial magneto-electronic phase separation has recently been observed in epitaxial thin films of the doped perovskite cobaltite La1-xSrxCoO3 at doping values where no such phase separation exists in bulk. Such systems also display anomalously large coercivity, which is not understood. To achieve a better understanding of this phenomenon we have extended this study to Nd1-xSrxCoO3 (x = 0.5), the perovskite cobaltite with the largest coercivity in bulk. Thin films of Nd0.5Sr0.5CoO3 are grown via high pressure reactive sputtering on SrTiO3 (001) substrates. We have observed a rapid deterioration in magnetization and onset of large intercluster-type magnetoresistance below a critical thickness of 80 å, signatures of interfacial magneto-electronic phase separation also seen in our earlier work on La1-xSrxCoO3. The temperature, angular, and thickness dependence of the coercivity (Hc) was studied using magnetoresistance. Low temperature HC values become very large (up to 3.6 Tesla) at low thickness, and a strong, superlinear T dependence emerges. We propose that the coercivity enhancement arises due to efficient domain wall pinning by the inhomogeneous magnetically phase separated region near the SrTiO3 substrate.

Sharma, M.; Gazquez, J.; Varela, M.; Leighton, C.

2009-03-01

401

The Conceptual Design of a Magnetic Tape Seal System.  

National Technical Information Service (NTIS)

A conceptual design of a magnetic tape seal system, capable of in-situ verification, is proposed for possible applications in nuclear safeguards systems. The system makes use of magnetic recording techniques for the deposition and retrieval of identificat...

H. Y. Soo

1981-01-01

402

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

403

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

404

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

405

Actively Controlled Magnetic Vibration-Isolation System  

NASA Technical Reports Server (NTRS)

Prototype magnetic suspension system with active control isolates object from vibrations in all six degrees of freedom at frequencies as low as 0.01 Hz. Designed specifically to protect instruments aboard spacecraft by suppressing vibrations to microgravity levels; basic control approach used for such terrestrial uses as suppression of shocks and other vibrations in trucks and railroad cars.

Grodsinky, Carlos M.; Logsdon, Kirk A.; Wbomski, Joseph F.; Brown, Gerald V.

1993-01-01

406

A communication system using magnetic fields  

Microsoft Academic Search

A new wireless communication system using a low frequency signal transmitted by current loop antennas is proposed. The communication range is relatively small (about several meters) so that the range is included in near field of a carrier signal. The use of magnetic fields makes it possible to provide high quality communication in an unfavorable environment where metal or fluids

Yun-Jae Won; Shin-Jae Kang; Sun-Hee Kim; David Choi; Seung-Ok Lim

2009-01-01

407

Magnetic particle clutch controls servo system  

NASA Technical Reports Server (NTRS)

Magnetic clutches provide alternative means of driving low-power rate or positioning servo systems. They may be used over wide variety of input speed ranges and weigh comparatively little. Power drain is good with overall motor/clutch efficiency greater than 50 percent, and gain of clutch is close to linear, following hysteresis curve of core and rotor material.

Fow, P. B.

1973-01-01

408

System characterization of a magnetically suspended flywheel  

NASA Technical Reports Server (NTRS)

The purpose of flywheel energy storage is to provide a means to save energy during times when the satellite is in sunlight, and then return the energy during the time when the satellite is in darkness. Typically, an energy storage device operates cyclically, where for satellites in Low Earth Orbit (LEO) the typical period is 60 minutes of sunlight followed by 30 minutes of darkness. If a lifetime of 17 years is required the energy storage system must be capable of sustaining approximately 100,000 cycles. The recent developments at the University of Maryland and how these progressions apply to a 500 Watt-hour magnetically suspended flywheel stack energy storage system are covered. The work includes hardware testing results from a stack flywheel energy storage system, improvements in the area of non-contacting displacement transducers, and performance enhancements of magnetic bearings. The experimental results show that a stack flywheel energy storage system is a feasible technology.

Kirk, James A.; Anand, Dave K.; Plant, David P.

1988-01-01

409

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

410

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

411

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

412

STP Textbook Chapter 5: Magnetic Systems  

NSDL National Science Digital Library

We apply the general formalism of statistical mechanics developed in Chapter 4 to the Ising model, a model magnetic system for which the interactions between the magnetic moments are important. We will discover that these interactions lead to a wide range of phenomena, including the existence of phase transitions and other cooperative phenomena. Computer simulation methods will be used extensively and a simple approximation method known as mean-field theory will be introduced. The simulations can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan

2008-05-28

413

Observing solitons in one dimensional magnetic systems  

SciTech Connect

Classical models of one dimensional magnetic systems show that in addition to the linear spin wave excitations, there should exist localized, large amplitude excitations, that can move along the chains while retaining their integrity. It is expected that these excitations, solitons, exist in real materials. The progress that has been made to date in observing solitons in one dimensional magnets by means of neutron scattering, and the difficulties that still remain in unambiguously identifying the soliton contributions to S(q,..omega..) are discussed.

Reiter, G.

1981-01-01

414

A desktop magnetic resonance imaging system.  

PubMed

Modern magnetic resonance imaging (MRI) systems consist of several complex, high cost subsystems. The cost and complexity of these systems often makes them impractical for use as routine laboratory instruments, limiting their use to hospitals and dedicated laboratories. However, advances in the consumer electronics industry have led to the widespread availability of inexpensive radio-frequency integrated circuits with exceptional abilities. We have developed a small, low-cost MR system derived from these new components. When combined with inexpensive desktop magnets, this type of MR scanner has the promise of becoming standard laboratory equipment for both research and education. This paper describes the development of a prototype desktop MR scanner utilizing a 0.21 T permanent magnet with an imaging region of approximately 2 cm diameter. The system uses commercially available components where possible and is programmed in LabVIEW software. Results from 3D data sets of resolution phantoms and fixed, newborn mice demonstrate the capability of this system to obtain useful images from a system constructed for approximately $13,500. PMID:11755094

Wright, Steven M; Brown, David G; Porter, Jay R; Spence, David C; Esparza, Emilio; Cole, David C; Huson, F Russell

2002-01-01

415

Propulsion and stabilization system for magnetically levitated vehicles  

DOEpatents

A propulsion and stabilization system for an inductive repulsion type magnetically levitated vehicle which is propelled and stabilized by a system which includes propulsion windings mounted above and parallel to vehicle-borne suspension magnets. A linear synchronous motor is part of the vehicle guideway and is mounted above and parallel to superconducting magnets attached to the magnetically levitated vehicle.

Coffey, Howard T. (Darien, IL)

1993-06-29

416

Electronic phase separation due to magnetic polaron formation in the semimetallic ferromagnet EuB6 — A weakly-nonlinear-transport study  

NASA Astrophysics Data System (ADS)

We report measurements of weakly nonlinear electronic transport, as measured by third-harmonic voltage generation V 3?, in the low-carrier density semimetallic ferromagnet EuB6, which exhibits an unusual magnetic ordering with two consecutive transitions at T_{c_1 } = 15.6K and T_{c_2 } = 12.5K. In contrast to the linear resistivity, the third-harmonic voltage is sensitive to the microgeometry of the electronic system. Our measurements provide evidence for magnetically-driven electronic phase separation consistent with the picture of percolation of magnetic polarons (MP), which form highly conducting magnetically ordered clusters in a paramagnetic and less conducting background. Upon cooling in zero magnetic field through the ferromagnetic transition, the dramatic drop in the linear resistivity at the upper transition T_{c_1 } coincides with the onset of nonlinearity, and upon further cooling is followed by a pronounced peak in V 3? at the lower transition T_{c_2 } . Likewise, in the paramagnetic regime, a drop of the material's magnetoresistance R( H) precedes a magnetic-fieldinduced peak in nonlinear transport. A striking observation is a linear temperature dependence of V {3?/peak}. We suggest a picture where at the upper transition T_{c_1 } the coalescing MP form a conducting path giving rise to a strong decrease in the resistance. The MP formation sets in at around T* ˜ 35K below which these entities are isolated and strongly fluctuating, while growing in number. The MP then start to form links at T_{c_1 } , where percolative electronic transport is observed. The MP merge and start forming a continuum at the threshold T_{c_2 } . In the paramagnetic temperature regime T_{c_1 } < T < T*, MP percolation is induced by a magnetic field, and the threshold accompanied by charge carrier delocalization occurs at a single critical magnetization.

Amyan, Adham; Das, Pintu; Müller, Jens; Fisk, Zachary

2013-05-01

417

A semi-automatic parachute separation system for balloon payloads  

Microsoft Academic Search

At the National Scientific balloon Facility (NSBF), when operating stratospheric balloons with scientific payloads, the current practice for separating the payload from the parachute after descent requires the sending of commands, over a UHF uplink, from the chase airplane or the ground control site. While this generally works well, there have been occasions when, due to shadowing of the receive

M. Farman

2002-01-01

418

Model System Studies with a Phase Separated Membrane Bioreactor.  

National Technical Information Service (NTIS)

The operation and evaluation of a bioreactor designed for high intensity oxygen transfer in a microgravity environment is described. The reactor itself consists of a zero headspace liquid phase separated from the air supply by a long length of silicone ru...

G. R. Petersen P. K. Seshan E. H. Dunlop

1989-01-01

419

Kinetics of phase separation in systems exhibiting simple coacervation  

NASA Astrophysics Data System (ADS)

The kinetics of phase separation of a homogeneous polyelectrolytic solution into a dense polymer-rich coacervate and the dilute supernatant phase is discussed through statistical thermodynamics. It has been shown that the coacervate phase is associated with higher internal pressure, consequently giving rise to syneresis. Physical conditions for phase separations has been deduced explicitly which reveals that ?2/I? constant (where ? is polyelectrolyte charge density and I is solution ionic strength), consistent with experimental observations. In the lattice model, r is the number of sites occupied by the polymer having a volume critical fraction ?2c , it was found that phase separation would ensue when ?3r?(64/9?2)[?2c/(1-?2c)2] , which reduces to (?3r/?2c)?(64/9?2)?0.45 at 20 °C for ?2c?1 . The separation kinetics mimics a spinodal decomposition process. Rate of release of supernatant due to syneresis was found to be independent of the initial coacervate mass. Syneresis results are discussed in the context of temporal evolution of self-organization in polymer melts through Avrami model.

Gupta, Amarnath; Bohidar, H. B.

2005-07-01

420

HMS: towards hierarchical mapping system for ID\\/locator separation  

Microsoft Academic Search

Recently, Internet Default Free Zone (DFZ) is facing a scalability problem due to the double use of the current Internet Protocol (IP) namespace. IP namespace is used for both the location finding and host identification. However, scalability is not the only problem, mobility is difficult to achieve due to the dual use of IP. Therefore, Identifier and Locator separation is

Mukankunga Bisamaza Angel; Rim Rhaw; Jun Lee; Choong Seon Hong

2011-01-01

421

Separation of Closely Related Systems by Molecular Sieve Zeolites  

Microsoft Academic Search

Molecular sieve zeolites are robust, thermally stable selective absorbents. They are chemically pure crystalline aluminosilicates with up to 50% of their crystal volume available for adsorption. Zeolites are widely used for industrial drying, purification, and separation, as well as catalysts and ion exchangers. They can be synthesized, on a plant scale, from silica (or sodium silicate) and sodium aluminate. The

A. Dyer

1978-01-01

422

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

423

Cell separation by non-inertial force fields in microfluidic systems  

Microsoft Academic Search

Cell and microparticle separation in microfluidic systems has recently gained significant attention in sample preparations for biological and chemical studies. Microfluidic separation is typically achieved by applying differential forces on the target particles to guide them into different paths. This paper reviews basic concepts and novel designs of such microfluidic separators with emphasis on the use of non-inertial force fields,

Hideaki Tsutsui; Chih-Ming Ho

2009-01-01

424

Multi-column step-gradient chromatography system for automated ion exchange separations  

SciTech Connect

A multi-column step-gradient chromatography system has been designed to perform automated sequential separations of radionuclides by ion exchange chromatography. The system consists of a digital programmer with automatic stream selection valve, two peristaltic pumps, ten columns, and a fraction collector. The automation allows complicated separations of radionuclides to be made with minimal analyst attention and allows for increased productivity and reduced cost of analyses. Results are reported for test separations on mixtures of radionuclides by the system.

Rucker, T.L.

1985-01-01

425

Two separate, but interacting, neural systems for familiarity and novelty detection: A dual-route mechanism.  

PubMed

It has long been assumed that familiarity- and novelty-related processes fall on a single continuum drawing on the same cognitive and neural mechanisms. The possibility that familiarity and novelty processing involve distinct neural networks was explored in a functional magnetic resonance imaging study (fMRI), in which familiarity and novelty judgments were made in contexts emphasizing either familiarity or novelty decisions. Parametrically modulated BOLD responses to familiarity and novelty strength were isolated in two separate, nonoverlapping brain networks. The novelty system involved brain regions along the ventral visual stream, the hippocampus, and the perirhinal and parahippocampal cortices. The familiarity system, on the other hand, involved the dorsomedial thalamic nucleus, and regions within the medial prefrontal cortex and the medial and lateral parietal cortex. Convergence of the two networks, treating familiarity and novelty as a single continuum was only found in a fronto-parietal network. Finally, the orbitomedial prefrontal cortex was found to be sensitive to reported strength/confidence, irrespective of stimulus' familiarity or novelty. This pattern of results suggests a dual-route mechanism supported by the existence of two distinct but interacting functional systems for familiarity and novelty. Overall, these findings challenge current assumptions regarding the neural systems that support the processing of novel and familiar information, and have important implications for research into the neural bases of recognition memory. © 2014 Wiley Periodicals, Inc. PMID:24436072

Kafkas, Alexandros; Montaldi, Daniela

2014-05-01