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Sample records for nanotube magnet technology

  1. Magnetic carbon nanotubes: preparation, physical properties, and applications in biomedicine.

    Science.gov (United States)

    Samadishadlou, Mehrdad; Farshbaf, Masoud; Annabi, Nasim; Kavetskyy, Taras; Khalilov, Rovshan; Saghfi, Siamak; Akbarzadeh, Abolfazl; Mousavi, Sepideh

    2017-10-18

    Magnetic carbon nanotubes (MCNTs) have been widely studied for their potential applications in medicine, diagnosis, cell biology, analytical chemistry, and environmental technology. Introduction of MCNTs paved the way for the emergence of new approaches in nanobiotechnology and biomedicine as a result of their multifarious properties embedded within either the carbon nanotubes (CNTs) or magnetic parts. Numerous preparation techniques exists for functionalizing CNTs with magnetic nanoparticles, and these versatile strategies lay the ground for the generation of novel and versatile systems which are applicable to many industries and biological areas. Here, we review and discuss the recent papers dealing with MCNTs and their application in biomedical and industrial fields.

  2. Novel Magnetic Zinc Oxide Nanotubes for Phenol Adsorption: Mechanism Modeling

    Directory of Open Access Journals (Sweden)

    Marwa F. Elkady

    2017-11-01

    Full Text Available Considering the great impact of a material’s surface area on adsorption processes, hollow nanotube magnetic zinc oxide with a favorable surface area of 78.39 m2/g was fabricated with the assistance of microwave technology in the presence of poly vinyl alcohol (PVA as a stabilizing agent followed by sonic precipitation of magnetite nano-particles. Scanning electron microscopy (SEM and transmission electron microscopy (TEM micrographs identified the nanotubes’ morphology in the synthesized material with an average aspect ratio of 3. X-ray diffraction (XRD analysis verified the combination of magnetite material with the hexagonal wurtzite structure of ZnO in the prepared material. The immobilization of magnetite nanoparticles on to ZnO was confirmed using vibrating sample magnetometry (VSM. The sorption affinity of the synthesized magnetic ZnO nanotube for phenolic compounds from aqueous solutions was examined as a function of various processing factors. The degree of acidity of the phenolic solution has great influence on the phenol sorption process on to magnetic ZnO. The calculated value of ΔH0 designated the endothermic nature of the phenol uptake process on to the magnetic ZnO nanotubes. Mathematical modeling indicated a combination of physical and chemical adsorption mechanisms of phenolic compounds on to the fabricated magnetic ZnO nanotubes. The kinetic process correlated better with the second-order rate model compared to the first-order rate model. This result indicates the predominance of the chemical adsorption process of phenol on to magnetic ZnO nanotubes.

  3. Spin wave spectrum of magnetic nanotubes

    International Nuclear Information System (INIS)

    Gonzalez, A.L.; Landeros, P.; Nunez, Alvaro S.

    2010-01-01

    We investigate the spin wave spectra associated to a vortex domain wall confined within a ferromagnetic nanotube. Basing our study upon a simple model for the energy functional we obtain the dispersion relation, the density of states and dissipation induced life-times of the spin wave excitations in presence of a magnetic domain wall. Our aim is to capture the basics spin wave physics behind the geometrical confinement of nobel magnetic textures.

  4. Doping of wide-bandgap titanium-dioxide nanotubes: optical, electronic and magnetic properties

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Cerkovnik, Logan Jerome; Nagpal, Prashant

    2014-08-01

    Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications.Doping semiconductors is an important step for their technological application. While doping bulk semiconductors can be easily achieved, incorporating dopants in semiconductor nanostructures has proven difficult. Here, we report a facile synthesis method for doping titanium-dioxide (TiO2) nanotubes that was enabled by a new electrochemical cell design. A variety of optical, electronic and magnetic dopants were incorporated into the hollow nanotubes, and from detailed studies it is shown that the doping level can be easily tuned from low to heavily-doped semiconductors. Using desired dopants - electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties can be tailored, and these technologically important nanotubes can be useful for a variety of applications in photovoltaics, display technologies, photocatalysis, and spintronic applications. Electronic supplementary information (ESI) available: See DOI: 10.1039/c4nr02417f

  5. Magnetic properties of carbon nanotubes with and without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lipert, Kamil; Ritschel, Manfred; Leonhardt, Albrecht; Krupskaya, Yulia; Buechner, Bernd; Klingeler, Ruediger, E-mail: k.lipert@ifw-dresden.d [Leibniz Institute for Solid State and Materials Research (IFW) Dresden (Germany)

    2010-01-01

    In this paper we report on the magnetic properties of single- and multiwalled carbon nanotubes synthesized using different chemical vapour deposition methods and with variety of catalyst materials (ferromagnetic Fe, FeCo and diamagnetic Re). Different methods yield carbon nanotubes with different morphologies and different quantity of residual catalyst material. Catalyst particles are usually encapsulated in the nanotubes and influence the magnetic respond of the samples. Varying ferromagnetic properties depending on the shape, size and type of catalyst are discussed in detail. The data are compared with M(H) characteristics of carbon nanotubes without catalysts and with nonmagnetic rhenium, as a reference.

  6. Magnetic fusion technology

    CERN Document Server

    Dolan, Thomas J

    2014-01-01

    Magnetic Fusion Technology describes the technologies that are required for successful development of nuclear fusion power plants using strong magnetic fields. These technologies include: ? magnet systems, ? plasma heating systems, ? control systems, ? energy conversion systems, ? advanced materials development, ? vacuum systems, ? cryogenic systems, ? plasma diagnostics, ? safety systems, and ? power plant design studies. Magnetic Fusion Technology will be useful to students and to specialists working in energy research.

  7. Electronic properties of magnetically doped nanotubes

    Indian Academy of Sciences (India)

    Unknown

    Sharif Institute of Technology, and Institute for Physics and Mathematics, Tehran, Iran. †Institute for Materials Research, Tohoku University, Sendai, Japan. Abstract. ... The role of magnetic dopants has not been considered however. 2. Method.

  8. Investigation Effects of Magnetetic Impurity Doping on Average Magnetization of Semiconducting Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Saeedeh Ghafourian

    2011-01-01

    Full Text Available Single wall carbon nanotubes (SWCNT extensively are attractive from both theoretical and experimental point of view, due to its technological applications such as nano electronics devises. SWCNT are created by rolling a graphen sheet into a cyclindrical form. We have investigated the possibility of making a ferromagnetic semiconductor zigzag SWCNT by doping magnetic impurities. We found by increasing magnetic impurities doping on a zigzag SWCNT, average magnetization is increased and one can make a ferromagnetic semiconductor

  9. Magnetic properties and thermodynamics in a metallic nanotube

    International Nuclear Information System (INIS)

    Jiang, Wei; Li, Xiao-Xi; Guo, An-Bang; Guan, Hong-Yu; Wang, Zan; Wang, Kai

    2014-01-01

    A metallic nanotube composed of the ferromagnetic spin-3/2 inner shell and spin-1 outer shell with a ferrimagnetic interlayer coupling has been studied by using the effective-field theory with correlations (EFT). With both existence of the magnetic anisotropy and transverse field, we have studied effects of them on the magnetic properties and the thermodynamics. Some interesting phenomena have been found in the phase diagrams. At low temperature, the magnetization curves present different behaviors. Two compensation points have been found for the certain values of the system parameters in the system. The research results of metallic nanotubes may have potential applications in the fields of biomedicine and molecular devices. - Highlights: • A hexagonal metallic nanotube is composed of spin-3/2 inner layer and spin-1 outer layer. • Various types of magnetization curves depend on physical parameters and temperature. • We study the effects of physical parameters on the magnetic properties and thermodynamics

  10. Dysprosium Acetylacetonato Single-Molecule Magnet Encapsulated in Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ryo Nakanishi

    2016-12-01

    Full Text Available Dy single-molecule magnets (SMMs, which have several potential uses in a variety of applications, such as quantum computing, were encapsulated in multi-walled carbon nanotubes (MWCNTs by using a capillary method. Encapsulation was confirmed by using transmission electron microscopy (TEM. In alternating current magnetic measurements, the magnetic susceptibilities of the Dy acetylacetonato complexes showed clear frequency dependence even inside the MWCNTs, meaning that this hybrid can be used as magnetic materials in devices.

  11. Gate-dependent orbital magnetic moments in carbon nanotubes

    DEFF Research Database (Denmark)

    Jespersen, Thomas Sand; Grove-Rasmussen, Kasper; Flensberg, Karsten

    2011-01-01

    We investigate how the orbital magnetic moments of electron and hole states in a carbon nanotube quantum dot depend on the number of carriers on the dot. Low temperature transport measurements are carried out in a setup where the device can be rotated in an applied magnetic field, thus enabling...... accurate alignment with the nanotube axis. The field dependence of the level structure is measured by excited state spectroscopy and excellent correspondence with a single-particle calculation is found. In agreement with band structure calculations we find a decrease of the orbital magnetic moment...... with increasing electron or hole occupation of the dot, with a scale given by the band gap of the nanotube....

  12. Linear Optical Response of Silicon Nanotubes Under Axial Magnetic Field

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2013-01-01

    We investigated the optical properties of silicon nanotubes (SiNTs) in the low energy region, E < 0.5 eV, and middle energy region, 1.8 eV < E < 2 eV. The dependence of optical matrix elements and linear susceptibility on radius and magnetic field, in terms of one-dimensional (1-d) wavevector and subband index, is calculated using the tight-binding approximation. It is found that, on increasing the nanotube diameter, the low-energy peaks show red-shift and their intensities are decreased. Also, we found that in the middle energy region all tubes have two distinct peaks, where the energy position of the second peak is approximately constant and independent of the nanotube diameter. Comparing the band structure of these tubes in different magnetic fields, several differences are clearly seen, such as splitting of degenerate bands, creation of additional band-edge states, and bandgap modification. It is found that applying the magnetic field leads to a phase transition in zigzag silicon hexagonal nanotubes (Si h-NTs), unlike in zigzag silicon gear-like nanotubes (Si g-NTs), which remain semiconducting in any magnetic field. We found that the axial magnetic field has two effects on the linear susceptibility spectrum, namely broadening and splitting. The axial magnetic field leads to the creation of a peak with energy less than 0.2 eV in metallic Si h-NTs, whereas in the absence of a magnetic field such a transition is not allowed.

  13. The Application of Carbon Nanotubes in Magnetic Fluid Hyperthermia

    Directory of Open Access Journals (Sweden)

    Grzegorz Raniszewski

    2015-01-01

    Full Text Available The aim of this paper is to present the results of the investigation into the applications of carbon nanotubes with ferromagnetic nanoparticles as nanoheaters for targeted thermal ablation of cancer cells. Relevant nanoparticles’ characteristics were exploited in terms of their functionality for biomedical applications and their magnetic properties were examined to determine heat generation efficiency induced by the exposure of the particles to an alternating magnetic field. The influence of the electromagnetic field on the human body tissues was assessed, providing quantitative measures of the interaction. The behavior of a liquid containing magnetic particles, during the exposure to the alternating magnetic field, was verified. As for the application for the ferromagnetic carbon nanotubes, the authors investigated temperature distribution in human liver tumor together with Arrhenius tissue damage model and the thermal dose concept.

  14. Magnetic Suspension Technology Workshop

    International Nuclear Information System (INIS)

    Keckler, C.R.; Groom, N.J.; Britcher, C.P.

    1993-01-01

    In order to identify the state of magnetic suspension technology in such areas as rotating systems, pointing of experiments or subsystems, payload isolation, and superconducting materials, a workshop on Magnetic Suspension Technology was held at the Langley Research Center in Hampton, Virginia, on 2-4 Feb. 1988. The workshop included five technical sessions in which a total of 24 papers were presented. The technical sessions covered the areas of pointing, isolation, and measurement, rotating systems, modeling and control, and superconductors. A list of attendees is provided. Separate abstracts have been prepared for articles from this report

  15. Induced Magnetic Moment in Defected Single-Walled Carbon Nanotubes

    International Nuclear Information System (INIS)

    Liu Hong

    2006-01-01

    The existence of a large induced magnetic moment in defect single-walled carbon nanotube(SWNT) is predicted using the Green's function method. Specific to this magnetic moment of defect SWNT is its magnitude which is several orders of magnitude larger than that of perfect SWNT. The induced magnetic moment also shows certain remarkable features. Therefore, we suggest that two pair-defect orientations in SWNT can be distinguished in experiment through the direction of the induced magnetic moment at some Specific energy points

  16. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok; Da Costa, Pedro M. F. J.; Wolter, Anja U. B.; Maier, Diana; Buechner, Bernd; Hampel, Silke

    2013-01-01

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  17. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok

    2013-08-15

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  18. Magnetic Field Effect on Ultrashort Two-dimensional Optical Pulse Propagation in Silicon Nanotubes

    Science.gov (United States)

    Konobeeva, N. N.; Evdokimov, R. A.; Belonenko, M. B.

    2018-05-01

    The paper deals with the magnetic field effect which provides a stable propagation of ultrashort pulses in silicon nanotubes from the viewpoint of their waveform. The equation is derived for the electromagnetic field observed in silicon nanotubes with a glance to the magnetic field for two-dimensional optical pulses. The analysis is given to the dependence between the waveform of ultrashort optical pulses and the magnetic flux passing through the cross-sectional area of the nanotube.

  19. Dynamic interaction between localized magnetic moments in carbon nanotubes

    International Nuclear Information System (INIS)

    Costa, A T; Muniz, R B; Ferreira, M S

    2008-01-01

    Magnetic moments dilutely dispersed in a metallic host tend to be coupled through the conduction electrons of the metal. This indirect exchange coupling (IEC), known to occur for a variety of magnetic materials embedded in several different metallic structures, is of rather long range, especially for low-dimensional structures like carbon nanotubes. Motivated by recent claims that the indirect coupling between magnetic moments in precessional motion has a much longer range than its static counterpart, we consider here how magnetic atoms adsorbed to the walls of a metallic nanotube respond to a time-dependent perturbation that induces their magnetic moments to precess. By calculating the frequency-dependent spin susceptibility, we are able to identify resonant peaks whose respective widths provide information about the dynamic aspect of the IEC. We show that by departing from a purely static representation to another in which the moments are allowed to precess, we change from what is already considered a long-range interaction to another whose range is far superior. In other words, localized magnetic moments embedded in a metallic structure can feel each other's presence more easily when they are set in precessional motion. We argue that such an effect can have useful applications leading to large-scale spintronics devices

  20. NMR strategies to study the local magnetic properties of carbon nanotubes

    KAUST Repository

    Abou-Hamad, Edy; Kim, Younghyun; Bouhrara, Mohamed; Saih, Youssef; Wå gberg, Thomas; Luzzi, David E.; Goze-Bac, Christophe

    2012-01-01

    The local magnetic properties of the one dimensional inner space of the nanotubes are investigated using 13C nuclear magnetic resonance spectroscopy of encapsulated fullerene molecules inside single walled carbon nanotubes. Isotope engineering and magnetically purified nanotubes have been advantageously used on our study to discriminate between the different diamagnetic and paramagnetic shifts of the resonances. Ring currents originating from the π electrons circulating on the nanotube, are found to actively screen the applied magnetic field by -36.9 ppm. Defects and holes in the nanotube walls cancel this screening locally. What is interesting, that at high magnetic fields, the modifications of the NMR resonances of the molecules from free to encapsulated can be exploited to determine some structural characteristics of the surrounding nanotubes, never observed experimentally. © 2011 Elsevier B.V. All rights reserved.

  1. NMR strategies to study the local magnetic properties of carbon nanotubes

    KAUST Repository

    Abou-Hamad, Edy

    2012-02-01

    The local magnetic properties of the one dimensional inner space of the nanotubes are investigated using 13C nuclear magnetic resonance spectroscopy of encapsulated fullerene molecules inside single walled carbon nanotubes. Isotope engineering and magnetically purified nanotubes have been advantageously used on our study to discriminate between the different diamagnetic and paramagnetic shifts of the resonances. Ring currents originating from the π electrons circulating on the nanotube, are found to actively screen the applied magnetic field by -36.9 ppm. Defects and holes in the nanotube walls cancel this screening locally. What is interesting, that at high magnetic fields, the modifications of the NMR resonances of the molecules from free to encapsulated can be exploited to determine some structural characteristics of the surrounding nanotubes, never observed experimentally. © 2011 Elsevier B.V. All rights reserved.

  2. Magnetism for understanding catalyst analysis of purified carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Bellouard, Christine; Mercier, Guillaume; Cahen, Sébastien; Ghanbaja, Jaafar; Medjahdi, Ghouti [Institut Jean Lamour, CNRS-Université de Lorraine, BP 70239, 54506 Vandoeuvre-lès-Nancy (France); Gleize, Jérôme [Laboratoire de Chimie Physique-Approche Multi-échelle de Milieux Complexes-Université de Lorraine, 1 Bd Arago, 57078 Metz (France); Lamura, Gianrico [CNR-SPIN – Dipartimento di Fisica, via Dodecaneso 33, 16146 Genova (Italy); Hérold, Claire [Institut Jean Lamour, CNRS-Université de Lorraine, BP 70239, 54506 Vandoeuvre-lès-Nancy (France); Vigolo, Brigitte, E-mail: Brigitte.Vigolo@univ-lorraine.fr [Institut Jean Lamour, CNRS-Université de Lorraine, BP 70239, 54506 Vandoeuvre-lès-Nancy (France)

    2016-08-01

    The precise quantification of catalyst residues in purified carbon nanotubes is often a major issue in view of any fundamental and/or applicative studies. More importantly, since the best CNTs are successfully grown with magnetic catalysts, their quantification becomes strictly necessary to better understand intrinsic properties of CNT. For these reasons, we have deeply analyzed the catalyst content remained in nickel–yttrium arc-discharge single walled carbon nanotubes purified by both a chlorine-gas phase and a standard acid-based treatment. The study focuses on Ni analysis which has been investigated by transmission electron microscopy, X-ray diffraction, thermogravimetry analysis, and magnetic measurements. In the case of the acid-based treatment, all quantifications result in a decrease of the nanocrystallized Ni by a factor of two. In the case of the halogen gas treatment, analysis and quantification of Ni content is less straightforward: a huge difference appears between X-ray diffraction and thermogravimetry results. Thanks to magnetic measurements, this disagreement is explained by the presence of Ni{sup 2+} ions, belonging to NiCl{sub 2} formed during the Cl-based purification process. In particular, NiCl{sub 2} compound appears under different magnetic/crystalline phases: paramagnetic or diamagnetic, or well intercalated in between carbon sheets with an ordered magnetic phase at low temperature. - Highlights: • Cl-gas treatment of Ni catalyst of carbon nanotubes leads to NiCl{sub 2} residue. • Magnetic measurements show the transformation of Ni{sup 0} in Ni{sup 2+}through a purification process. • High temperature Cl treatment removes 75% of metallic impurities. • Cl-purification yields to an amount of metal of 1.5% in arc-discharge CNT samples.

  3. Investigation of magnetism in aluminum-doped silicon carbide nanotubes

    Science.gov (United States)

    Behzad, Somayeh; Chegel, Raad

    2013-11-01

    The effect of aluminum doping on the structural, electronic and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) is investigated using spin-polarized density functional theory. It is found from the calculation of the formation energies that aluminum substitution for silicon atom is preferred. Our results show that the magnetization depends on the substitutional site, aluminum substitution at silicon site does not introduce any spin-polarization, whereas the aluminum substitution for carbon atom yields a spin polarized, almost dispersionless π band within the original band gap.

  4. Magnetic susceptibility of molecular carbon: nanotubes and fullerite

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, A P; Haddon, R C; Zhou, O; Fleming, R M; Zhang, J; McClure, S M; Smalley, R E [AT T Bell Laboratories, Murray Hill, NJ (United States)

    1994-07-01

    Elemental carbon can be synthesized in a variety of geometrical forms, from three-dimensional extended structures (diamond) to finite molecules (C[sub 60] fullerite). Results are presented here on the magnetic susceptibility of the least well-understood members of this family, nanotubes and C[sub 60] fullerite. (1) Nanotubes represent the cylindrical form of carbon, intermediate between graphite and fullerite. They are found to have significantly larger orientation-averaged susceptibility, on a per carbon basis, than any other form of elemental carbon. This susceptibility implies an average band structure among nanotubes similar to that of graphite. (2) High-resolution magnetic susceptibility data on C[sub 60] fullerite near the molecular orientational-ordering transition at 259 K show a sharp jump corresponding to 2.5 centimeter-gram-second parts per million per mole of C[sub 60]. This jump directly demonstrates the effect of an intermolecular cooperative transition on an intramolecular electronic property, where the susceptibility jump may be ascribed to a change in the shape of the molecule due to lattice forces.

  5. Effects of C3+ ion irradiation on structural, electrical and magnetic properties of Ni nanotubes

    Science.gov (United States)

    Shlimas, D. I.; Kozlovskiy, A. L.; Zdorovets, M. V.; Kadyrzhanov, K. K.; Uglov, V. V.; Kenzhina, I. E.; Shumskaya, E. E.; Kaniukov, E. Y.

    2018-03-01

    Ion irradiation is an attractive method for obtaining nanostructures that can be used under extreme conditions. Also, it is possible to control the technological process that allows obtaining nanomaterials with new properties at ion irradiation. In this paper, we study the effect of irradiation with 28 MeV C3+ ions and fluences up to 5 × 1011 cm-2 on the structure and properties of template-synthesized nickel nanotubes with a length of 12 μm, with diameters of 400 nm, and a wall thickness of 100 nm. It is demonstrated that the main factor influencing the degradation of nanostructures under irradiation in PET template is the processes of mixing the material of nanostructures with the surrounding polymer. The influence of irradiation with various fluences on the crystal structure, electrical and magnetic properties of nickel nanotubes is studied.

  6. Electromagnetic properties of inner double walled carbon nanotubes investigated by nuclear magnetic resonance

    KAUST Repository

    Bouhrara, M.; Abou-Hamad, E.; Alabedi, G.; Al-Taie, I.; Kim, Y.; Wagberg, T.; Goze-Bac, C.

    2013-01-01

    The nuclear magnetic resonance (NMR) analytical technique was used to investigate the double walled carbon nanotubes (DWNTs) electromagnetic properties of inner walls. The local magnetic and electronic properties of inner nanotubes in DWNTs were analyzed using 25% 13C enriched C 60 by which the effect of dipolar coupling could be minimized. The diamagnetic shielding was determined due to the ring currents on outer nanotubes in DWNTs. The NMR chemical shift anisotropy (CSA) spectra and spin-lattice relaxation studies reveal the metallic properties of the inner nanotubes with a signature of the spin-gap opening below 70 K.

  7. Magnetoresponsive conductive colloidal suspensions with magnetized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Abdalla, Ahmed M. [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Abdel Fattah, Abdel Rahman [Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Ghosh, Suvojit [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Puri, Ishwar K., E-mail: ikpuri@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada); Department of Mechanical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2017-01-01

    We synthesize a novel and hitherto unreported class of colloidal suspensions for which the dispersed phase, which consists of multiwall carbon nanotubes (MWNTs) decorated with magnetic nanoparticles (MNPs), is both magnetoresponsive and electrically conductive. Synthesis of the dispersed phase merges processes for producing ferrofluids and magnetic MWNTs (mMWNTs). We explore means to tune the properties of these magnetic conductive colloids (MCCs) by varying the (1) MNP material composition, and (2) MNP:MWNT (w/w) magnetization weight ratio (γ). The mMWNTs are examined using XRD, TEM, EDX and SQUID and MCCs are by measuring their zeta potential and electric conductivity. Magnetite (Fe{sub 3}O{sub 4}) MNPs, which possess a high Curie temperature, produce mMWNTs with high saturation magnetization that respond relatively weakly to temperature variations. Mn{sub 0.2}Cu{sub 0.2}Zn{sub 0.6}Fe{sub 2}O{sub 4} and Cu{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} MNPs with lower Curie temperatures are more sensitive to changing temperature. Increasing the MNP Cu content improves the electric conductivity of the corresponding MCC while increasing γ enhances its magnetic response. After γ is raised above a threshold value, mMWNT decoration on the CNT surface becomes nonuniform since the MNPs now agglomerate perpendicular to the nanotube surface. These colloidal suspensions are a promising new class of material that can be manipulated with a magnetic field to tune their electrical conductivity. - Highlights: ●We synthesize a novel and hitherto unreported class of colloidal suspensions. ●These colloidal suspensions are both magnetoresponsive and electrically conductive. ●The dispersed phase consists of MWNTs decorated with different magnetic nanoparticles. ●These colloids have enhanced magnetic response and electric conductivity (up to 169.5 mS cm{sup −1}). ●It is a promising new class of material that can be manipulated with a magnetic field.

  8. Magnetic study of iron-containing carbon nanotubes: Feasibility for magnetic hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Krupskaya, Y. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany)], E-mail: y.krupskaya@ifw-dresden.de; Mahn, C.; Parameswaran, A. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany); Taylor, A.; Kraemer, K. [Department of Urology, Dresden University of Technology, 01307 Dresden (Germany); Hampel, S.; Leonhardt, A.; Ritschel, M.; Buechner, B.; Klingeler, R. [Leibniz-Institute for Solid State and Materials Research IFW Dresden, 01171 Dresden (Germany)

    2009-12-15

    We present a detailed magnetic study of iron containing carbon nanotubes (Fe-CNT), which highlights their potential for contactless magnetic heating in hyperthermia cancer treatment. Magnetic field dependent AC inductive heating experiments on Fe-CNT dispersions show a substantial temperature increase of Fe-CNT dispersions in applied AC magnetic fields. DC and AC magnetization studies have been done in order to elucidate the heating mechanism. We observe a different magnetic response of Fe-CNT powder compared to Fe-CNT dispersed in aqueous solution, e.g., ferromagnetic Fe-CNT in powder do not show any hysteresis when being dispersed in liquid. Our data indicate the motion of Fe-CNT in liquid in applied magnetic fields.

  9. Magnetic Particle Technology

    Science.gov (United States)

    Oliveira, Luiz C.A.; A. Rios, Rachel V.R.; Fabris, Jose D.; Lago, Rachel M.; Sapag, Karim

    2004-01-01

    An exciting laboratory environment is activated by the preparation and novel use of magnetic materials to decontaminate water through adsorption and magnetic removal of metals and organics. This uncomplicated technique is also adaptable to the possible application of adsorbents to numerous other environmental substances.

  10. Interfacial adsorption and surfactant release characteristics of magnetically functionalized halloysite nanotubes for responsive emulsions.

    Science.gov (United States)

    Owoseni, Olasehinde; Nyankson, Emmanuel; Zhang, Yueheng; Adams, Daniel J; He, Jibao; Spinu, Leonard; McPherson, Gary L; Bose, Arijit; Gupta, Ram B; John, Vijay T

    2016-02-01

    Magnetically responsive oil-in-water emulsions are effectively stabilized by a halloysite nanotube supported superparamagnetic iron oxide nanoparticle system. The attachment of the magnetically functionalized halloysite nanotubes at the oil-water interface imparts magnetic responsiveness to the emulsion and provides a steric barrier to droplet coalescence leading to emulsions that are stabilized for extended periods. Interfacial structure characterization by cryogenic scanning electron microscopy reveals that the nanotubes attach at the oil-water interface in a side on-orientation. The tubular structure of the nanotubes is exploited for the encapsulation and release of surfactant species that are typical of oil spill dispersants such as dioctyl sulfosuccinate sodium salt and polyoxyethylene (20) sorbitan monooleate. The magnetically responsive halloysite nanotubes anchor to the oil-water interface stabilizing the interface and releasing the surfactants resulting in reduction in the oil-water interfacial tension. The synergistic adsorption of the nanotubes and the released surfactants at the oil-water interface results in oil emulsification into very small droplets (less than 20μm). The synergy of the unique nanotubular morphology and interfacial activity of halloysite with the magnetic properties of iron oxide nanoparticles has potential applications in oil spill dispersion, magnetic mobilization and detection using magnetic fields. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Loading and release of doxorubicin with magnetic nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xia; Wang, Xiang; Lee, Sang Bok [Dept. of Chemistry and Biochemistry, University of Maryland, College Park (United States); English, Douglas [Dept. of Chemistry, Wichita State University, Wichita (United States)

    2015-03-15

    In this work, we study magnetic nanotubes (MNTs) as drug carriers to control the loading and release of doxorubicin (Dox). The inner surfaces of MNTs where Dox molecules are stored are modified with C18-silane and pyridine–silane. By tuning the interaction between the drug molecules and inner surfaces of MNTs via pH, Dox can be effectively encapsulated at pH 7.2 and released at pH 4.5. The successful loading of Dox is confirmed with confocal microscopy studies. The release profiles of Dox from modified MNTs are detected by spectrofluorophotometry, with bare MNTs as control. With proper modifications, MNTs can be used for pH-dependent, controlled release of drug molecules.

  12. Structural anisotropy of magnetically aligned single wall carbon nanotube films

    International Nuclear Information System (INIS)

    Smith, B. W.; Benes, Z.; Luzzi, D. E.; Fischer, J. E.; Walters, D. A.; Casavant, M. J.; Schmidt, J.; Smalley, R. E.

    2000-01-01

    Thick films of aligned single wall carbon nanotubes and ropes have been produced by filtration/deposition from suspension in strong magnetic fields. We measured mosaic distributions of rope orientations in the film plane, for samples of different thicknesses. For an ∼1 μm film the full width at half maximum (FWHM) derived from electron diffraction is 25 degree sign -28 degree sign . The FWHM of a thicker film (∼7 μm) measured by x-ray diffraction is slightly broader, 35±3 degree sign . Aligned films are denser than ordinary filter-deposited ones, and much denser than as-grown material. Optimization of the process is expected to yield smaller FWHMs and higher densities. (c) 2000 American Institute of Physics

  13. The effects of functional magnetic nanotubes with incorporated nerve growth factor in neuronal differentiation of PC12 cells

    International Nuclear Information System (INIS)

    Xie Jining; Chen Linfeng; Varadan, Vijay K; Yancey, Justin; Srivatsan, Malathi

    2008-01-01

    In this in vitro study the efficiency of magnetic nanotubes to bind with nerve growth factor (NGF) and the ability of NGF-incorporated magnetic nanotubes to release the bound NGF are investigated using rat pheochromocytoma cells (PC12 cells). It is found that functional magnetic nanotubes with NGF incorporation enabled the differentiation of PC12 cells into neurons exhibiting growth cones and neurite outgrowth. Microscope observations show that filopodia extending from neuron growth cones were in close proximity to the NGF-incorporated magnetic nanotubes, at times appearing to extend towards or into them. These results show that magnetic nanotubes can be used as a delivery vehicle for NGF and thus may be exploited in attempts to treat neurodegenerative disorders such as Parkinson's disease with neurotrophins. Further neurite outgrowth can be controlled by manipulating magnetic nanotubes with external magnetic fields, thus helping in directed regeneration

  14. Stable magnetization of iron filled carbon nanotube MFM probes in external magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Wolny, Franziska; Weissker, Uhland; Muehl, Thomas; Lutz, Matthias U; Mueller, Christian; Leonhardt, Albrecht; Buechner, Bernd, E-mail: f.wolny@ifw-dresden.d [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany)

    2010-01-01

    We present results on the application of an iron filled carbon nanotube (Fe-CNT) as a probe for magnetic force microscopy (MFM) in an external magnetic field. If an external field is applied parallel to the sample surface, conventional ferromagnetically coated MFM probes often have the disadvantage that the magnetization of the coating turns towards the direction of the applied field. Then it is difficult to distinguish the effect of the external field on the sample from those on the MFM probe. The Fe-CNT MFM probe has a large shape anisotropy due to the high aspect ratio of the enclosed iron nanowire. Thanks to this the direction of the magnetization stays mainly oriented along the long nanotube axis in in-plane fields up to our experimental limit of 250 mT. Thus, the quality of the MFM images remains unchanged. Apart from this, it is shown that Fe-CNT MFM probe yields a very good magnetic resolution of about 25 nm due to the small diameter of the iron filling.

  15. Influence of the structural properties on the pseudocritical magnetic behavior of single-wall ferromagnetic nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Salazar-Enriquez, C.D. [PCM Computational Applications, Universidad Nacional de Colombia - Sede Manizales, A.A. 127 Manizales (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [PCM Computational Applications, Universidad Nacional de Colombia - Sede Manizales, A.A. 127 Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulacion Gplus, Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia)

    2012-04-15

    In this work we address the influence of the crystalline structure, concretely when the system under study is formed by square or hexagonal unit cells, upon the magnetic properties and pseudocritical behavior of single-wall ferromagnetic nanotubes. We focus not only on the effect of the geometrical shape of the unit cell but also on their dimensions. The model employed is based on the Monte Carlo method, the Metropolis dynamics and a nearest neighbors classical Heisenberg Hamiltonian. Magnetization per magnetic site, magnetic susceptibility, specific heat and magnetic energy were computed. These properties were computed varying the system size, unit cell dimension and temperature. The dependence of the nearest neighbor exchange integral on the nanotubes geometrical characteristics is also discussed. Results revealed a strong influence of the system topology on the magnetic properties caused by the difference in the coordination number between square and hexagonal unit cell. Moreover, the nanotubes diameter influence on magnetic properties is only observed at very low values, when the distance between atoms is less than it, presented by the 2D sheet. On the other hand, it was concluded that the surface-related finite-size effects do not influence the magnetic nanotubes properties, contrary to the case of other nano-systems as thin films and nanoparticles among others. - Highlights: Black-Right-Pointing-Pointer Unit cell geometry has strong influence on the magnetic properties in ferromagnetic nanotubes. Black-Right-Pointing-Pointer The nanotube diameter increase produces a decrease of interaction between nearest neighbor. Black-Right-Pointing-Pointer Surface-related finite-size effects do not influence the magnetic nanotubes properties.

  16. Influence of the structural properties on the pseudocritical magnetic behavior of single-wall ferromagnetic nanotubes

    International Nuclear Information System (INIS)

    Salazar-Enríquez, C.D.; Restrepo-Parra, E.; Restrepo, J.

    2012-01-01

    In this work we address the influence of the crystalline structure, concretely when the system under study is formed by square or hexagonal unit cells, upon the magnetic properties and pseudocritical behavior of single-wall ferromagnetic nanotubes. We focus not only on the effect of the geometrical shape of the unit cell but also on their dimensions. The model employed is based on the Monte Carlo method, the Metropolis dynamics and a nearest neighbors classical Heisenberg Hamiltonian. Magnetization per magnetic site, magnetic susceptibility, specific heat and magnetic energy were computed. These properties were computed varying the system size, unit cell dimension and temperature. The dependence of the nearest neighbor exchange integral on the nanotubes geometrical characteristics is also discussed. Results revealed a strong influence of the system topology on the magnetic properties caused by the difference in the coordination number between square and hexagonal unit cell. Moreover, the nanotubes diameter influence on magnetic properties is only observed at very low values, when the distance between atoms is less than it, presented by the 2D sheet. On the other hand, it was concluded that the surface-related finite-size effects do not influence the magnetic nanotubes properties, contrary to the case of other nano-systems as thin films and nanoparticles among others. - Highlights: ► Unit cell geometry has strong influence on the magnetic properties in ferromagnetic nanotubes. ► The nanotube diameter increase produces a decrease of interaction between nearest neighbor. ► Surface-related finite-size effects do not influence the magnetic nanotubes properties.

  17. Superconductivity and magnet technology

    International Nuclear Information System (INIS)

    Lubell, M.S.

    1975-01-01

    The background theory of superconducting behavior is reviewed. Three parameters that characterize superconducting materials with values of commercial materials as examples are discussed. More than 1000 compounds and alloy systems and 26 elements are known to exhibit superconducting properties under normal conditions at very low temperatures. A wide variety of crystal structures are represented among the known superconductors. The most important ones do seem to have cubic symmetry such as the body-centered cubic (NbZr and NbTi), face-centered cubic (NbN), and the A15 or β-tungsten structures (Nb 3 Sn), V 3 Ga, Nb 3 Ge, Nb 3 Al, and V 3 Si). Attempts to understand some of the particular phenomena associated with superconductors as a necessary prelude to constructing superconducting magnets are discussed by the author. The origin of degradation is briefly discussed and methods to stabilize magnets are illustrated. The results of Oak Ridge National Laboratory design studies of toroidal magnet systems for fusion reactors are described

  18. Electronic, magnetic and transport properties of graphene ribbons terminated by nanotubes

    International Nuclear Information System (INIS)

    Akhukov, M A; Yuan Shengjun; Fasolino, A; Katsnelson, M I

    2012-01-01

    We study, by density functional and large-scale tight-binding transport calculations, the electronic structure, magnetism and transport properties of the recently proposed graphene ribbons with edges rolled to form nanotubes. Edges with armchair nanotubes present magnetic moments localized either in the tube or the ribbon and of metallic or half-metallic character, depending on the symmetry of the junction. These properties have potential for spin valve and spin filter devices with advantages over other proposed systems. Edges with zigzag nanotubes are either metallic or semiconducting without affecting the intrinsic mobility of the ribbon. Varying the type and size of the nanotubes and ribbons offers the possibility to tailor the magnetic and transport properties, making these systems very promising for applications. (paper)

  19. Fabrication of DNA nanotubes with an array of exterior magnetic nanoparticles.

    Science.gov (United States)

    Rafati, Adele; Zarrabi, Ali; Gill, Pooria

    2017-10-01

    Described here a methodology for arraying of magnetic nanoparticles (MNPs) on the surface of DNA nanotubes (DNTs). Positioning of magnetic nanoparticles at exterior surface of DNTs were shaped after self-assembling of oligonucleotide staples within an M13mp18 DNA scaffold via an origami process. The staples were partially labeled with biotin to be arrayed at the surface of DNTs. Gel retardation assay of the DNTs carrying magnetic nanoparticles indicated a reversely behavioral electrophoretic movement in comparison to the nanotubes have been demonstrated previously. Also, high resolution transmission electron microscopy confirmed positioning magnetic nanoparticles at the exterior surface of DNTs, correctly. Ultrastructural characteristics of these DNA nanotubes using atomic force microscopy demonstrated topographic heights on their surfaces formed through positioning of magnetic nanoparticles outside the tubules. This nanoarchitecture would be potential for multiple arraying of nanoparticles that those be useful as functionalized chimeric nanocarriers for developing novel nanodrugs and nanobiosensors. Copyright © 2017. Published by Elsevier B.V.

  20. Comparison of Electronic Structure and Magnetic Properties of Few Layer Graphene and Multiwall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Sekhar Chandra Ray

    2016-01-01

    Full Text Available A comparative study has been made for the non-catalyst based few layer graphene (FLG and Fe-catalyst based multiwall carbon nanotubes (MWCNTs. Magnetic and electronic properties of FLG and MWCNTs were studied using magnetic M-H hysteresis loops and synchrotron radiation based X-ray absorption fine structure spectroscopy measurements. Structural defects and electronic and bonding properties of FLG/MWCNTs have been studied using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS, and ultraviolet photoelectron spectroscopy (UPS. The work functions of FLG and MWCNTs are 4.01 eV and 3.79 eV, respectively, obtained from UPS (He-I spectra. UPS (He-II results suggest that the density of states (DOS of MWCNTs is higher than FLG and is consistent with Raman spectroscopy result that shows the defect of MWCNTs is higher than FLG. The magnetic coercivity (Hc of the MWCNTs (~750 Oe is higher than FLG (~85 Oe which could be used for various technological magnetic applications.

  1. Features of electron-phonon interactions in nanotubes with chiral symmetry in magnetic field

    CERN Document Server

    Kibis, O V

    2001-01-01

    Interaction of the electrons with acoustic phonons in the nanotube with chiral symmetry by availability of the magnetic field, parallel to the nanotube axis, is considered. It is shown that the electron energy spectrum is asymmetric relative to the electron wave vector inversion and for that reason the electron-phonon interaction appears to be different for similar phonons with mutually contrary directions of the wave vector. This phenomenon leads to origination of the electromotive force by the spatially uniform electron gas heating and to appearance of the quadrupole component in the nanotube volt-ampere characteristics

  2. Magnetic impurities in single-wall carbon nanotubes and graphene: a review

    Czech Academy of Sciences Publication Activity Database

    Vejpravová, Jana; Pacáková, Barbara; Kalbáč, Martin

    2016-01-01

    Roč. 141, č. 9 (2016), s. 2639-2656 ISSN 0003-2654 R&D Projects: GA MŠk LL1301 Institutional support: RVO:68378271 ; RVO:61388955 Keywords : graphene * carbon nanotube * magnetic impurities Subject RIV: BM - Solid Matter Physics ; Magnetism; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 3.885, year: 2016

  3. Technology of magnetically driven accelerators

    International Nuclear Information System (INIS)

    Brix, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-01-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

  4. Technology of magnetically driven accelerators

    International Nuclear Information System (INIS)

    Birx, D.L.; Hawkins, S.A.; Poor, S.E.; Reginato, L.L.; Smith, M.W.

    1985-01-01

    The marriage of Induction Linac technology with Nonlinear Magnetic Modulators has produced some unique capabilities. It appears possible to produce electron beams with average currents measured in amperes, at gradients exceeding 1 MeV/meter, and with power efficiencies approach 50%. A 2 MeV, 5 kA electron accelerator has been constructed at the Lawrence Livermore National Laboratory (LLNL) to demonstrate these concepts and to provide a test facility for high brightness sources. The pulse drive for the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak power capability, repetition rates exceeding a kilohertz and excellent reliability

  5. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, Remi; Bouhrara, M.; Kim, Y.; Wå gberg, T.; Goze-Bac, C.; Abou-Hamad, Edy

    2015-01-01

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play

  6. Magnetic and electronic properties of single-walled Mo2C nanotube: a first-principles study

    Science.gov (United States)

    Jalil, Abdul; Sun, Zhongti; Wang, Dayong; Wu, Xiaojun

    2018-04-01

    The structural, electronic, and magnetic properties of single-walled Mo2C nanotubes are investigated by using first-principles calculations. We establish that single-walled Mo2C nanotubes can be rolled up from a graphene-like Mo2C monolayer with H- or T-type phase, i.e. H-Mo2C and T-Mo2C nanotubes. The armchair-type T-Mo2C nanotubes are more energetically stable than H-Mo2C nanotubes with the same diameter, while zigzag-type H-Mo2C nanotubes are more energetically stable than T-Mo2C nanotubes. In particular, (8, 0) H-Mo2C nanotube are more stable than Mo2C monolayer due to structural deformation. All Mo2C nanotubes are magnetic metals, independent of their chirality, and the magnetic moments of Mo atoms in the outer layer are larger than the inner. The ionic and metallic bonds in Mo2C nanotubes and delocalized electrons around Mo atoms lead to the versatile electronic and magnetic properties in them, endowing them potential applications in catalysts and electronics.

  7. Magnetization Reversal Mechanism for CoFeB Ferromagnetic Nanotube Arrays

    International Nuclear Information System (INIS)

    Hai-Rui, Liu; Qing-Feng, Lu; Shamaila, S.; Jun-Yang, Chen; Sharif, R.; Xiu-Feng, Han

    2009-01-01

    CoFeB nanotube arrays are fabricated in anodic aluminum oxide (AAO) membranes and track etched polycarbonate (PCTE) membranes by using an electrochemical method, and their magnetic properties are investigated by vibrating sample magnetometry. The coercivity H c and remanent squareness S Q of these CoFeB nanotube arrays are derived from hysteresis loops as a function of angle between the field and tube axis. The H c (θ) curves for CoFeB nanotube arrays in AAO and PCTE membranes show M-type variation, while they change shape from M to mountain-type as the tube length increases. However, the overall easy axis perpendicular to tube axis does not change with tube length. The different angular dependences are attributed to different magnetization reversal mechanisms. (condensed matter: electronicstructure, electrical, magnetic, and opticalproperties)

  8. Bioinspired peptide nanotubes: deposition technology, basic physics and nanotechnology applications.

    Science.gov (United States)

    Rosenman, G; Beker, P; Koren, I; Yevnin, M; Bank-Srour, B; Mishina, E; Semin, S

    2011-02-01

    Synthetic peptide monomers can self-assemble into PNM such as nanotubes, nanospheres, hydrogels, etc. which represent a novel class of nanomaterials. Molecular recognition processes lead to the formation of supramolecular PNM ensembles containing crystalline building blocks. Such low-dimensional highly ordered regions create a new physical situation and provide unique physical properties based on electron-hole QC phenomena. In the case of asymmetrical crystalline structure, basic physical phenomena such as linear electro-optic, piezoelectric, and nonlinear optical effects, described by tensors of the odd rank, should be explored. Some of the PNM crystalline structures permit the existence of spontaneous electrical polarization and observation of ferroelectricity. The PNM crystalline arrangement creates highly porous nanotubes when various residues are packed into structural network with specific wettability and electrochemical properties. We report in this review on a wide research of PNM intrinsic physical properties, their electronic and optical properties related to QC effect, unique SHG, piezoelectricity and ferroelectric spontaneous polarization observed in PNT due to their asymmetric structure. We also describe PNM wettability phenomenon based on their nanoporous structure and its influence on electrochemical properties in PNM. The new bottom-up large scale technology of PNT physical vapor deposition and patterning combined with found physical effects at nanoscale, developed by us, opens the avenue for emerging nanotechnology applications of PNM in novel fields of nanophotonics, nanopiezotronics and energy storage devices. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.

  9. Dipolar interaction in arrays of magnetic nanotubes

    International Nuclear Information System (INIS)

    Velázquez-Galván, Y; Martínez-Huerta, J M; Encinas, A; De La Torre Medina, J; Danlée, Y; Piraux, L

    2014-01-01

    The dipolar interaction field in arrays of nickel nanotubes has been investigated on the basis of expressions derived from the effective demagnetizing field of the assembly as well as magnetometry measurements. The model incorporates explicitly the wall thickness and aspect ratio, as well as the spatial order of the nanotubes. The model and experiment show that the interaction field in nanotubes is smaller than that in solid nanowires due to the packing fraction reduction in tubes related to their inner cavity. Finally, good agreement between the model and experiment is found for the variation of the interaction field as a function of the tube wall thickness. (paper)

  10. Etching processes of transparent carbon nanotube thin films using laser technologies

    International Nuclear Information System (INIS)

    Lin, H.K.; Lin, R.C.; Li, C.H.

    2010-01-01

    Carbon nanotubes (CNTs) have potential as a transparent conductive material with good mechanical and electrical properties. However, carbon nanotube thin film deposition and etching processes are very difficult to pattern the electrode. In this study, transparent CNT film with a binder is coated on a PET flexible substrate. The transmittance and sheet resistance of carbon nanotube film are 84% and 1000 Ω/□, respectively. The etching process of carbon nanotube film on flexible substrates was investigated using 355 nm and 1064 nm laser sources. Experimental results show that carbon nanotube film can be ablated using laser technology. With the 355 nm UV laser, the minimum etched line width was 20 μm with a low amount of recast material of the ablated sections. The optimal conditions of laser ablation were determined for carbon nanotube film.

  11. Superconducting magnets technologies for large accelerator

    International Nuclear Information System (INIS)

    Ogitsu, Toru

    2017-01-01

    The first hadron collider with superconducting magnet technologies was built at Fermi National Accelerator Laboratory as TEVATRON. Since then, the superconducting magnet technologies are widely used in large accelerator applications. The paper summarizes the superconducting magnet technologies used for large accelerators. (author)

  12. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

    2016-05-15

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

  13. Conductive Carbon Nanotube Inks for Use with Desktop Inkjet Printing Technology

    Science.gov (United States)

    Roberson, Luke; Williams, Martha; Tate, LaNetra; Fortier, Craig; Smith, David; Davia, Kyle; Gibson, Tracy; Snyder, Sarah

    2013-01-01

    Inkjet printing is a common commercial process. In addition to the familiar use in printing documents from computers, it is also used in some industrial applications. For example, wire manufacturers are required by law to print the wire type, gauge, and safety information on the exterior of each foot of manufactured wire, and this is typically done with inkjet or laser printers. The goal of this work was the creation of conductive inks that can be applied to a wire or flexible substrates via inkjet printing methods. The use of inkjet printing technology to print conductive inks has been in testing for several years. While researchers have been able to get the printing system to mechanically work, the application of conductive inks on substrates has not consistently produced adequate low resistances in the kilohm range. Conductive materials can be applied using a printer in single or multiple passes onto a substrate including textiles, polymer films, and paper. The conductive materials are composed of electrical conductors such as carbon nanotubes (including functionalized carbon nanotubes and metal-coated carbon nanotubes); graphene, a polycyclic aromatic hydrocarbon (e.g., pentacene and bisperipentacene); metal nanoparticles; inherently conductive polymers (ICP); and combinations thereof. Once the conductive materials are applied, the materials are dried and sintered to form adherent conductive materials on the substrate. For certain formulations, increased conductivity can be achieved by printing on substrates supported by low levels of magnetic field alignment. The adherent conductive materials can be used in applications such as damage detection, dust particle removal, smart coating systems, and flexible electronic circuitry. By applying alternating layers of different electrical conductors to form a layered composite material, a single homogeneous layer can be produced with improved electrical properties. It is believed that patterning alternate layers of

  14. Hyperthermia in low aspect-ratio magnetic nanotubes for biomedical applications

    Science.gov (United States)

    Gutierrez-Guzman, D. F.; Lizardi, L. I.; Otálora, J. A.; Landeros, P.

    2017-03-01

    A simple model for the magnetization reversal process of low aspect-ratio ferromagnetic nanotubes (MNTs) is presented. Because of advantages over other geometries, these structures are interesting for biomedical applications, such as magnetic hyperthermia cancer therapy, where the heat released during magnetic reversal is used to destroy tumors. For example, the tubular geometry provides two independent functional surfaces that may be selectively manipulated and also gives a storage cavity. Owing to their large surface to weight ratio and low mass density, MNTs are not decanted by gravity. We calculated magnetic phase diagrams, energy barriers, nucleation fields, and the amount of dissipated heat and specific absorption rate for magnetite nanotubes. The geometrical parameters were varied, and simple formulae were used to optimize the tube response under alternating excitation, as required for magnetic hyperthermia applications.

  15. Preparation of magnetic carbon nanotubes (Mag-CNTs) for biomedical and biotechnological applications.

    Science.gov (United States)

    Masotti, Andrea; Caporali, Andrea

    2013-12-18

    Carbon nanotubes (CNTs) have been widely studied for their potential applications in many fields from nanotechnology to biomedicine. The preparation of magnetic CNTs (Mag-CNTs) opens new avenues in nanobiotechnology and biomedical applications as a consequence of their multiple properties embedded within the same moiety. Several preparation techniques have been developed during the last few years to obtain magnetic CNTs: grafting or filling nanotubes with magnetic ferrofluids or attachment of magnetic nanoparticles to CNTs or their polymeric coating. These strategies allow the generation of novel versatile systems that can be employed in many biotechnological or biomedical fields. Here, we review and discuss the most recent papers dealing with the preparation of magnetic CNTs and their application in biomedical and biotechnological fields.

  16. Carbon Nanotubes Technology for Removal of Arsenic from Water

    Directory of Open Access Journals (Sweden)

    Ali Naghizadeh

    2012-08-01

    Full Text Available Please cite this article as: Naghizadeh A, Yari AR, Tashauoei HR, Mahdavi M, Derakhshani E, Rahimi R, Bahmani P. Carbon nanotubes technology for removal of arsenic from water. Arch Hyg Sci 2012;1(1:6-11. Aims of the Study: This study was aimed to investigate the adsorption mechanism of the arsenic removal from water by using carbon nanotubes in continuous adsorption column. Materials & Methods: Independent variables including carbon nanotubes dosage, contact time and breakthrough point were carried out to determine the influence of these parameters on the adsorption capacity of the arsenic from water. Results: Adsorption capacities of single wall and multiwall carbon nanotubes were about 148 mg/g and 95 mg/g respectively. The experimental data were analyzed using Langmuir and Freundlich isotherm models and equilibrium data indicate the best fit obtained with Langmuir isotherm model. Conclusions: Carbon nanotubes can be considered as a promising adsorbent for the removal of arsenic from large volume of aqueous solutions. References: 1. Lomaquahu ES, Smith AH. Feasibility of new epidemiology studies on arsenic exposures at low levels. AWWA Inorganic Contaminants Workshop. San Antonio; 1998. 2. Burkel RS, Stoll RC. Naturally occurring arsenic in sandstone aquifer water supply wells of North Eastern Wisconsin. Ground Water Monit Remediat 1999;19(2:114-21. 3. Mondal P, Majumder CB, Mohanty B. Laboratory based approaches for arsenic remediation from contaminated water: recent developments. J Hazard Mater 2006;137(1: 464-79. 4. Meenakshi RCM. Arsenic removal from water: a review. Asian J Water Environ Pollut 2006;3(1:133-9. 5. Wickramasinghe SR, Binbing H, Zimbron J, Shen Z, Karim MN. Arsenic removal by coagulation and filtration: comparison of ground waters from United States and Bangladesh. Desalination 2004;169:231-44. 6. Hossain MF. Arsenic contamination in Bangladesh-an overview. Agric Ecosyst Environ 2006;113(1-4:1-16. 7. USEPA, Arsenic. Final

  17. Carbon nanotubes in an inhomogeneous transverse magnetic field: exactly solvable model

    Czech Academy of Sciences Publication Activity Database

    Jakubský, Vít; Kuru, S.; Negro, J.

    2014-01-01

    Roč. 47, č. 11 (2014), s. 115307 ISSN 1751-8113 R&D Projects: GA AV ČR GPP203/11/P038 Institutional support: RVO:61389005 Keywords : carbon nanotubes * dirac equation * magnetic field * finite-gap system Subject RIV: BE - Theoretical Physics Impact factor: 1.583, year: 2014

  18. Superconductor technology for fusion magnets

    International Nuclear Information System (INIS)

    Dustmann, C.H.; Juengst, K.P.; Komarek, P.; Krafft, G.; Krauth, H.; Maier, P.; Ries, G.; Schauer, W.; Schmidt, C.; Seibt, E.; Turowski, P.

    1976-11-01

    The development of advanced suoerconductors for magnets in fusion experiments is an essential problem. In this report the parameters of a big Tokamak magnet system are presented and the resulting constraints for the conductor are given. Comparing this constraints with the state of the art of the magnet and conductor technology, the goals of the needed conductor development are defined. Existing conductor concepts are described. Based on considerations on the main problems (cooling concepts, mechanical stress analysis, stabilization, ac-losses) a concept of an economically feasable and cryogenically stabilized flat cable conductor is developed. Typical parameters of a 10 kA conductor with NbTi at 8 T are given. The experimental investigations needed for the conductor development are discussed. Existing devices for measurements of Isub(c), ac-losses and the behaviour of the conductor under mechanical stress are described and typical experimental results are presented. The need of the completion of the measuring devices and programmes is stressed. The construction of a versatile conductor test facility is proposed. (orig.) [de

  19. Electron Gas Dynamic Conductivity Tensor on the Nanotube Surface in Magnetic Field

    Directory of Open Access Journals (Sweden)

    A. M. Ermolaev

    2011-01-01

    Full Text Available Kubo formula was derived for the electron gas conductivity tensor on the nanotube surface in longitudinal magnetic field considering spatial and time dispersion. Components of the degenerate and nondegenerate electron gas conductivity tensor were calculated. The study has showed that under high electron density, the conductivity undergoes oscillations of de Haas-van Alphen and Aharonov-Bohm types with the density of electrons and magnetic field changes.

  20. Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): a density functional study.

    Science.gov (United States)

    Dhaka, Kapil; Bandyopadhyay, Debashis

    2016-08-02

    The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the first-principles density functional theory. We found that the transition metal doping and in addition, the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and density of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order.

  1. Cobalt nanorods fully encapsulated in carbon nanotube and magnetization measurements by off-axis electron holography

    International Nuclear Information System (INIS)

    Fujita, Takeshi; Hayashi, Yasuhiko; Tokunaga, Tomoharu; Yamamoto, Kazuo

    2006-01-01

    Fully encapsulated face-centered-cubic (fcc) Co nanorods in multiwalled carbon nanotubes were produced by microwave plasma enhanced chemical vapor deposition. Quantitative magnetization measurements of the Co nanorods were carried out by off-axis electron holography using a theoretical cylindrical model. The component of magnetic induction was then measured to be 1.2±0.1 T, which is lower than the expected saturation magnetization of fcc Co of 1.7 T. The reason for the reduced magnetic component was discussed

  2. Rapid microwave-assisted regeneration of magnetic carbon nanotubes loaded with p-nitrophenol

    International Nuclear Information System (INIS)

    Cui, Chunyue; Zheng, Qingzhu; Han, Yanhe; Xin, Yanjun

    2015-01-01

    Highlights: • Magnetic CNTs material was successfully synthesized. • Magnetic CNTs have high fast adsorption rate and adsorption capacity. • Magnetic CNTs can be easily separated from the water by external magnetic field. • Magnetic CNTs can be recycled by MW irradiation regeneration. - Abstract: A novel magnetic carbon nanotubes (CNTs) adsorbent with good sorption, magnetic separability, and microwave (MW) regeneration properties was prepared successfully using thermal decomposition. The magnetic CNTs were characterized using transmission electron microscopy, energy dispersive X-ray, nitrogen adsorption (Brunauer–Emmett–Teller surface area), and X-ray diffraction and their magnetic properties were measured using a vibrating sample magnetometer. Magnetic nanoparticles (≈10 nm diameter) were dispersed uniformly on the CNTs with a magnetic CNTs surface area of 146.7 m 2 g −1 and a saturation magnetization of 21.11 emu g −1 . When the magnetic CNTs were used in the sorption of p-nitrophenol, the equilibrium time was 20 min and the sorption isotherms fit the Freundlich isotherm well. The spent magnetic CNTs could be separated magnetically and be regenerated by MW irradiation. After six adsorption and MW regeneration cycles (at 850 W for 180 s), the adsorption capacity of the magnetic CNTs was higher than that of the virgin magnetic CNTs with a low carbon loss

  3. Effect of magnetic field on thermal conductivity and viscosity of a magnetic nanofluid loaded with carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Shahsavar, Amin [Kermanshah University of Technology, Kermanshah (Iran, Islamic Republic of); Salimpour, Mohammad Reza; Saghafian, Mohsen [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Shafii, M. B. [Sharif University of Technology, Tehran(Iran, Islamic Republic of)

    2016-02-15

    The present work examines experimentally the effect of magnetic field on the viscosity and thermal conductivity of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe{sub 3}O{sub 4} nanoparticles and Gum arabic (GA) coated carbon nanotubes (CNTs). The hybrid nanofluid was prepared by using ultrasonic dispersion method. Magnetic field was created by a pair of spaced apart magnet plates. The effect of temperature on the time variation of thermal conductivity under applied magnetic field was also investigated. According to the results of this study, viscosity of the hybrid nanofluid increases with the strength of magnetic field, while it decreases with the increase of temperature. Additionally, it is found that the hybrid nanofluid behaves as a shear thinning fluid at low shear rates while it exhibits Newtonian behavior at high shear rates. Furthermore, results show that when an external magnetic field is applied to the studied magnetic nanofluids, the thermal conductivity experiences a peak.

  4. Magnetic behaviour of arrays of Ni nanowires by electrodeposition into self-aligned titania nanotubes

    International Nuclear Information System (INIS)

    Prida, V.M.; Hernandez-Velez, M.; Cervera, M.; Pirota, K.; Sanz, R.; Navas, D.; Asenjo, A.; Aranda, P.; Ruiz-Hitzky, E.; Batallan, F.; Vazquez, M.; Hernando, B.; Menendez, A.; Bordel, N.; Pereiro, R.

    2005-01-01

    Arrays of Ni nanowires electrodeposited into self-aligned and randomly disordered titania nanotube arrays grown by anodization process are investigated by X-ray diffraction, SEM, rf-GDOES and VSM magnetometry. The titania nanotube outer diameter is about 160 nm, wall thickness ranging from 60 to 70 nm and 300 nm in depth. The so-obtained Ni nanowires reach above 100 nm diameter and 240 nm length, giving rise to coercive fields of 98 and 200 Oe in the perpendicular or parallel to the nanowires axis hysteresis loops, respectively. The formation of magnetic vortex domain states is also discussed

  5. A novel molecularly imprinted material based on magnetic halloysite nanotubes for rapid enrichment of 2,4-dichlorophenoxyacetic acid in water

    International Nuclear Information System (INIS)

    Zhong, Shian; Zhou, Chengyun; Zhang, Xiaona; Zhou, Hui; Li, Hui; Zhu, Xiaohong; Wang, Yan

    2014-01-01

    Graphical abstract: - Highlights: • Successful preparation of a novel type of magnetic halloysite molecularly imprinted material. • Rapid enrichment for 2,4-dichlorophenoxyacetic acid in water. • This material possesses high adsorption capacity and specific recognition to 2,4-dichlorophenoxyacetic acid. • Magnetic halloysite were synthesized by co-precipitation method. - Abstract: A new type of magnetic halloysite nanotubes molecularly imprinted polymer (MHNTs@MIP) based on halloysite nanotubes (HNTs) with embedded magnetic nanoparticles was introduced in this study. MHNTs@MIP was prepared through surface imprinting technology, using 2,4-dichlorophenoxyacetic acid (2,4-D) as a template, 4-vinylpyridine as the monomer, divinylbenzene as cross-linking agents, and 2,2-azodiisobutyronitrile as initiator. MHNTs@MIP was characterized by Fourier Transform Infrared Spectrometer, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometer. MHNTs@MIP exhibited rapid and reliable analysis with supermagnetic properties, as well as repeated use and template-specific recognition. The adsorption capacity of magnetic halloysite nanotubes non-imprinted polymer (MHNTs@NIP) and MHNTs@MIP was 10.3 mg/g and 35.2 mg/g, respectively. In the detailed discussion on specific selectivity, MHNTs@MIP can be applied as an adsorbent for sample pretreatment extraction and obtain high recoveries of about 85–94%. After extraction, high-performance liquid chromatography was used to detect 2,4-D residue in water

  6. A novel molecularly imprinted material based on magnetic halloysite nanotubes for rapid enrichment of 2,4-dichlorophenoxyacetic acid in water

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Shian; Zhou, Chengyun; Zhang, Xiaona [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhou, Hui [Cancer Hospital of Xiangya Medical College, Central South University, Changsha 410013 (China); Li, Hui; Zhu, Xiaohong [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Wang, Yan, E-mail: yanwangcsu@163.com [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2014-07-15

    Graphical abstract: - Highlights: • Successful preparation of a novel type of magnetic halloysite molecularly imprinted material. • Rapid enrichment for 2,4-dichlorophenoxyacetic acid in water. • This material possesses high adsorption capacity and specific recognition to 2,4-dichlorophenoxyacetic acid. • Magnetic halloysite were synthesized by co-precipitation method. - Abstract: A new type of magnetic halloysite nanotubes molecularly imprinted polymer (MHNTs@MIP) based on halloysite nanotubes (HNTs) with embedded magnetic nanoparticles was introduced in this study. MHNTs@MIP was prepared through surface imprinting technology, using 2,4-dichlorophenoxyacetic acid (2,4-D) as a template, 4-vinylpyridine as the monomer, divinylbenzene as cross-linking agents, and 2,2-azodiisobutyronitrile as initiator. MHNTs@MIP was characterized by Fourier Transform Infrared Spectrometer, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometer. MHNTs@MIP exhibited rapid and reliable analysis with supermagnetic properties, as well as repeated use and template-specific recognition. The adsorption capacity of magnetic halloysite nanotubes non-imprinted polymer (MHNTs@NIP) and MHNTs@MIP was 10.3 mg/g and 35.2 mg/g, respectively. In the detailed discussion on specific selectivity, MHNTs@MIP can be applied as an adsorbent for sample pretreatment extraction and obtain high recoveries of about 85–94%. After extraction, high-performance liquid chromatography was used to detect 2,4-D residue in water.

  7. The precise self-assembly of individual carbon nanotubes using magnetic capturing and fluidic alignment

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Joon S; Rust, Michael J; Do, Jaephil; Ahn, Chong H [Department of Electrical and Computer Engineering, Microsystems and BioMEMS Laboratory, University of Cincinnati, Cincinnati, OH 45221 (United States); Yun, Yeo-Heung; Schulz, Mark J [Department of Mechanical Engineering, University of Cincinnati, 45221 (United States); Shanov, Vesselin, E-mail: chong.ahn@uc.ed [Department of Chemical and Materials Engineering, University of Cincinnati, 45221 (United States)

    2009-08-12

    A new method for the self-assembly of a carbon nanotube (CNT) using magnetic capturing and fluidic alignment has been developed and characterized in this work. In this new method, the residual iron (Fe) catalyst positioned at one end of the CNT was utilized as a self-assembly driver to attract and position the CNT, while the assembled CNT was aligned by the shear force induced from the fluid flow through the assembly channel. The self-assembly procedures were successfully developed and the electrical properties of the assembled multi-walled carbon nanotube (MWNT) and single-walled carbon nanotube (SWNT) were fully characterized. The new assembly method developed in this work shows its feasibility for the precise self-assembly of parallel CNTs for electronic devices and nanobiosensors.

  8. Metal-functionalized single-walled graphitic carbon nitride nanotubes: a first-principles study on magnetic property

    Directory of Open Access Journals (Sweden)

    Shenoy Vivek

    2011-01-01

    Full Text Available Abstract The magnetic properties of metal-functionalized graphitic carbon nitride nanotubes were investigated based on first-principles calculations. The graphitic carbon nitride nanotube can be either ferromagnetic or antiferromagnetic by functionalizing with different metal atoms. The W- and Ti-functionalized nanotubes are ferromagnetic, which are attributed to carrier-mediated interactions because of the coupling between the spin-polarized d and p electrons and the formation of the impurity bands close to the band edges. However, Cr-, Mn-, Co-, and Ni-functionalized nanotubes are antiferromagnetic because of the anti-alignment of the magnetic moments between neighboring metal atoms. The functionalized nanotubes may be used in spintronics and hydrogen storage.

  9. Space-charge waves in magnetized and collisional quantum plasma columns confined in carbon nanotubes

    International Nuclear Information System (INIS)

    Bagheri, Mehran; Abdikian, Alireza

    2014-01-01

    We study the dispersion relation of electrostatic waves propagating in a column of quantum magnetized collisional plasma embraced completely by a metallic single-walled carbon nanotubes. The analysis is based on the quantum linearized hydrodynamic formalism of collective excitations within the quasi-static approximation. It is shown when the electronic de Broglie's wavelength of the plasma is comparable in the order of magnitude to the radius of the nanotube, the quantum effects are quite meaningful and our model anticipates one acoustical and two optical space-charge waves which are positioned into three propagating bands. With increasing the nanotube radius, the features of the acoustical branch remain unchanged, yet two distinct optical branches are degenerated and the classical behavior is recovered. This study might provide a platform to create new finite transverse cross section quantum magnetized plasmas and to devise nanometer dusty plasmas based on the metallic carbon nanotubes in the absence of either a drift or a thermal electronic velocity and their existence could be experimentally examined

  10. Superconducting Magnet Technology for the Upgrade

    Science.gov (United States)

    Todesco, E.; Ambrosio, G.; Ferracin, P.; Rifflet, J. M.; Sabbi, G. L.; Segreti, M.; Nakamoto, T.; van Weelderen, R.; Xu, Q.

    In this section we present the magnet technology for the High Luminosity LHC. After a short review of the project targets and constraints, we discuss the main guidelines used to determine the technology, the field/gradients, the operational margins, and the choice of the current density for each type of magnet. Then we discuss the peculiar aspects of each class of magnet, with special emphasis on the triplet.

  11. Superconducting Magnet Technology for the Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Todesco, E. [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TE Dept.; Ambrosio, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Ferracin, P. [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TE Dept.; Rifflet, J. M. [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TE Dept.; Sabbi, G. L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Segreti, M. [Alternative Energies and Atomic Energy Commission (CEA), Saclay (France); Nakamoto, T. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); van Weelderen, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TE Dept.; Xu, Q. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)

    2015-10-01

    In this section we present the magnet technology for the High Luminosity LHC. After a short review of the project targets and constraints, we discuss the main guidelines used to determine the technology, the field/gradients, the operational margins, and the choice of the current density for each type of magnet. Then we discuss the peculiar aspects of each class of magnet, with special emphasis on the triplet.

  12. Magnetic Carbon Nanotubes as a Theranostic Platform for Drug Delivery and Magnetic Resonance Imaging

    KAUST Repository

    Alkattan, Nedah

    2014-06-01

    Carbon nanotubes (CNTs) have special characteristics that made them good agents especially for biomedical applications. In this study, Fe3O4 nanoparticles were incorporated onto the surface of CNTs followed by polyethylene glycol (PEG) grafting forming CNTs-Fe3O4-PEG hybrids. The PEGylation improves their biocompatibility, water solubility, and increases blood circulation. CNTs-Fe3O4-PEG was used as T2-contrat agent for magnetic resonance imaging (MRI). In addition, doxorubicin (DOX) was loaded onto CNTs-Fe3O4-PEG. The release of DOX from DOX-loaded CNTs-Fe3O4-PEG was tested under different pH conditions (7.4, 6.3 and 5.2). The release increased at acidic pH compared to neutral pH, which shows the sensitivity of the system to pH change. Triggering the release by Near Infra-Red (NIR) irradiation was furthermore investigated. The release increased after irradiation with NIR compared to control sample. These result prove that the designed system can be triggered by an internal stimuli (pH) and external stimuli (NIR irradiation) making it a promising candidate to be used for biomedical applications.

  13. Augmentation of chain formation in a magnetic fluid by the addition of halloysite nanotubes

    International Nuclear Information System (INIS)

    Desai, Rucha; Upadhyay, R V; Mehta, R V

    2014-01-01

    The study aims to investigate the effect of the addition of nanotubes of halloysite on the augmentation of chains observed in an aqueous magnetic fluid consisting of co-precipitated magnetite particles stabilized with lauric acid. Three samples of the mixture containing 0.5%, 1% and 2% of halloysite nanotubes (HNTs) and a pure magnetic fluid are used for this study. A room temperature magnetization study shows that for 0.5% and 1% of HNT, the magnetization of the mixture significantly increases, while for the higher concentration (2%) it decreases. Such concentration dependent behaviour on the addition of a nonmagnetic system to a magnetic fluid has not previously been observed. The increase in the magnetization is attributed to smaller sized (<5–6 nm) magnetite attached to the HNT, forming a magnetite–HNT composite. Additionally, field-induced chaining is augmented by the addition of HNT in the magnetic fluid. The augmentation of chain formation is confirmed by optical microscopy, field-induced transmission changes and field-dependent diffraction effects. The augmentation will be useful in enhancing other properties of the composite, such as the viscosity and thermal conductivity of nanofluids. (paper)

  14. Magnetic and transport properties of Fe nanowires encapsulated in carbon nanotubes

    International Nuclear Information System (INIS)

    Munoz-Sandoval, E.; Lopez-Urias, F.; Diaz-Ortiz, A.; Terrones, M.; Reyes-Reyes, M.; Moran-Lopez, J.L.

    2004-01-01

    The magnetization reversal and magnetoresistance of two-dimensional arrays of aligned Fe-filled carbon nanotubes have been investigated. Our results show a linear temperature dependence of the coercivity above 10 K and a relative large hysteresis for the applied field perpendicular to the nanowires axes. A continuous decrease of the magnetoresistance for both field directions is observed. We attribute this behavior to the anisotropic nature of the system

  15. Carbon nanotubes/magnetite hybrids prepared by a facile synthesis process and their magnetic properties

    International Nuclear Information System (INIS)

    Zhang Li; Ni, Qing-Qing; Natsuki, Toshiaki; Fu Yaqin

    2009-01-01

    In this paper, a facile synthesis process is proposed to prepare multiwalled carbon nanotubes/magnetite (MWCNTs/Fe 3 O 4 ) hybrids. The process involves two steps: (1) water-soluble CNTs are synthesized by one-pot modification using potassium persulfate (KPS) as oxidant. (2) Fe 3 O 4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe 3 O 4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by X-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe 3 O 4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe 3 O 4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe 3 O 4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe 3 O 4 hybrids was discussed.

  16. Iron filled carbon nanotubes as novel monopole-like sensors for quantitative magnetic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wolny, F; Muehl, T; Weissker, U; Lipert, K; Schumann, J; Leonhardt, A; Buechner, B, E-mail: f.wolny@ifw-dresden.de, E-mail: t.muehl@ifw-dresden.de [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany)

    2010-10-29

    We present a novel ultrahigh stability sensor for quantitative magnetic force microscopy (MFM) based on an iron filled carbon nanotube. In contrast to the complex magnetic structure of conventional MFM probes, this sensor constitutes a nanomagnet with defined properties. The long iron nanowire can be regarded as an extended dipole of which only the monopole close to the sample surface is involved in the imaging process. We demonstrate its potential for high resolution imaging. Moreover, we present an easy routine to determine its monopole moment and prove that this calibration, unlike other approaches, is universally applicable. For the first time this enables straightforward quantitative MFM measurements.

  17. High magnetic fields science and technology

    CERN Document Server

    Miura, Noboru

    2003-01-01

    This three-volume book provides a comprehensive review of experiments in very strong magnetic fields that can only be generated with very special magnets. The first volume is entirely devoted to the technology of laboratory magnets: permanent, superconducting, high-power water-cooled and hybrid; pulsed magnets, both nondestructive and destructive (megagauss fields). Volumes 2 and 3 contain reviews of the different areas of research where strong magnetic fields are an essential research tool. These volumes deal primarily with solid-state physics; other research areas covered are biological syst

  18. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.Y.; Fu, M.J.; Tsai, C.Y. [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China); Lin, F.H. [Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (R.O.C.) (China); Chen, K.Y., E-mail: chenky@iner.gov.tw [Division of Isotope Application, Institute of Nuclear Energy Research, Atomic Energy Council, P.O. BOX 3-27 Longtan, Taoyuan County 32546, Taiwan (R.O.C.) (China)

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe{sub 3}O{sub 4} was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered. - Highlights: Dispersion ability of carbon nanotubes (CNTs) was improved by functionalization. CNTs were easily manipulated by precipitation of magnetic nanoparticles. Our product can be used as versatile biosensor substrate for biomarker screening.

  19. A novel molecularly imprinted material based on magnetic halloysite nanotubes for rapid enrichment of 2,4-dichlorophenoxyacetic acid in water.

    Science.gov (United States)

    Zhong, Shian; Zhou, Chengyun; Zhang, Xiaona; Zhou, Hui; Li, Hui; Zhu, Xiaohong; Wang, Yan

    2014-07-15

    A new type of magnetic halloysite nanotubes molecularly imprinted polymer (MHNTs@MIP) based on halloysite nanotubes (HNTs) with embedded magnetic nanoparticles was introduced in this study. MHNTs@MIP was prepared through surface imprinting technology, using 2,4-dichlorophenoxyacetic acid (2,4-D) as a template, 4-vinylpyridine as the monomer, divinylbenzene as cross-linking agents, and 2,2-azodiisobutyronitrile as initiator. MHNTs@MIP was characterized by Fourier Transform Infrared Spectrometer, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometer. MHNTs@MIP exhibited rapid and reliable analysis with supermagnetic properties, as well as repeated use and template-specific recognition. The adsorption capacity of magnetic halloysite nanotubes non-imprinted polymer (MHNTs@NIP) and MHNTs@MIP was 10.3mg/g and 35.2mg/g, respectively. In the detailed discussion on specific selectivity, MHNTs@MIP can be applied as an adsorbent for sample pretreatment extraction and obtain high recoveries of about 85-94%. After extraction, high-performance liquid chromatography was used to detect 2,4-D residue in water. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Advanced imaging technology using carbon nanotube x ray source

    International Nuclear Information System (INIS)

    Choi, Hae Young; Seol, Seung Kown; Kim, Jaehoon; Yoo, Seung Hoon; Kim, Jong Uk

    2008-01-01

    Recently, X ray imaging technology is a useful and leading medical diagnostic tool for healthcare professionals to diagnose disease in human body. CNTs(i.e. carbon nanotubes)are used in many applications like FED, Micro wave amplifier, X ray source, etc. because of its suitable electrical, chemical and physical properties. Specially, CNTs are well used electron emitters for x ray source. Conventionally, thermionic type of tungsten filament x ray tube is widely employed in the field of bio medical and industrial application fields. However, intrinsic problems such as, poor emission efficiency and low imaging resolution cause the limitation of use of the x ray tube. To fulfill the current market requirement specifically for medical diagnostic field, we have developed rather a portable and compact CNT based x ray source in which high imaging resolution is provided. Electron sources used in X ray tubes should be well focused to the anode target for generation of high quality x ray. In this study, Pierce type x ray generation module was tested based its simulation results using by OPERA 3D code. Pierce type module is composed of cone type electrical lens with its number of them and inner angles of them that shows different results with these parameters. And some preliminary images obtained using the CNT x ray source were obtained. The represented images are the finger bone and teeth in human body. It is clear that the trabeculation shape is observed in finger bone. To obtain the finger bone image, tube currents of 250A at 42kV tube voltage was applied. The human tooth image, however, is somewhat unclear because the supplied voltage to the tube was limited to max. 50kV in the system developed. It should be noted that normally 60∼70kV of tube voltage is supplied in dental imaging. Considering these it should be emphasized that if the tube voltage is over 60kV then clearer image is possible. In this paper, we are discussed comparing between these experiment results and

  1. Linear optical response of carbon nanotubes under axial magnetic field

    Science.gov (United States)

    Moradian, Rostam; Chegel, Raad; Behzad, Somayeh

    2010-04-01

    We considered single walled carbon naotubes (SWCNTs) as real three dimensional (3D) systems in a cylindrical coordinate. The optical matrix elements and linear susceptibility, χ(ω), in the tight binding approximation in terms of one-dimensional wave vector, kz and subband index, l are calculated. In an external axial magnetic field optical frequency dependence of linear susceptibility are investigated. We found that axial magnetic field has two effects on the imaginary part of the linear susceptibility spectrum, in agreement with experimental results. The first effect is broadening and the second, splitting. Also we found that for all metallic zigzag and armchair SWCNTs, the axial magnetic field leads to the creation of a peak with energy less than 1.5 eV, contrary to what is observed in the absence of a magnetic field.

  2. Synthesis and Magnetic Properties of Maghemite (γ-Fe2O3 Short-Nanotubes

    Directory of Open Access Journals (Sweden)

    Xiao XH

    2010-01-01

    Full Text Available Abstract We report a rational synthesis of maghemite (γ-Fe2O3 short-nanotubes (SNTs by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated γ-Fe2O3 SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (TB. The hysteresis loop was operated to show that the magnetic properties of γ-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

  3. Fabrication, morphological, structural and magnetic properties of electrodeposited Fe{sub 3}Pt nanowires and nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Khan, U. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Adeela, N. [Centre for High Energy Physics, University of the Punjab, Lahore 54000 (Pakistan); Li, Wenjing; Irfan, M.; Javed, K.; Riaz, S. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Han, X.F., E-mail: xfhan@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-02-15

    Highly ordered Fe{sub 3}Pt nanowires (NWs) and nanotubes (NTs) embedded in anodic aluminum oxide (AAO) template have been fabricated by dc electrodeposition method. Response of heat treatment on structural and magnetic properties of the samples has been studied with and without the presence of magnetic field (1 T). X-Ray Diffraction analysis shows chemically ordered L1{sub 2} face centered cubic (FCC) as the dominant phase for Fe{sub 3}Pt NWs and heat treatment improves crystallinity with retained its phase. Whereas, Fe{sub 3}Pt NTs show amorphous behavior with and without magnetic field annealing. Furthermore, magnetic properties of the samples have been investigated by vibrating sample magnetometer (VSM). Magnetic parameters of Fe{sub 3}Pt including magnetic coercivity, saturation magnetization, squareness and shape of MH-loops have been investigated as a result of simple and MF annealing. - Highlights: • Fe{sub 3}Pt NWs and NTs embedded into anodic alumina templates have been synthesized by dc electrodeposition method. • Structural analysis (XRD) confirmed the formation of fcc structure. • Magnetic properties have been measured as a function of simple and magnetic field annealing.

  4. Giant Magnetoresistance in Carbon Nanotubes with Single-Molecule Magnets TbPc2.

    Science.gov (United States)

    Krainov, Igor V; Klier, Janina; Dmitriev, Alexander P; Klyatskaya, Svetlana; Ruben, Mario; Wernsdorfer, Wolfgang; Gornyi, Igor V

    2017-07-25

    We present experimental results and a theoretical model for the gate-controlled spin-valve effect in carbon nanotubes with side-attached single-molecule magnets TbPc 2 (Terbium(III) bis-phthalocyanine). These structures show a giant magnetoresistance up to 1000% in experiments on single-wall nanotubes that are tunnel-coupled to the leads. The proposed theoretical model combines the spin-dependent Fano effect with Coulomb blockade and predicts a spin-spin interaction between the TbPc 2 molecules, mediated by conducting electrons via the charging effect. This gate-tuned interaction is responsible for the stable magnetic ordering of the inner spins of the molecules in the absence of magnetic field. In the case of antiferromagnetic arrangement, electrons with either spin experience the scattering by the molecules, which results in blocking the linear transport. In strong magnetic fields, the Zeeman energy exceeds the effective antiferromagnetic coupling and one species of electrons is not scattered by molecules, which leads to a much lower total resistance at the resonant values of gate voltage, and hence to a supramolecular spin-valve effect.

  5. A review of magnetic heat pump technology

    International Nuclear Information System (INIS)

    Barclay, J.A.

    1990-01-01

    The area of technology classified as heat pumps generally refers to refrigerators, heat pumps and heat engines. This review is restricted to the literature on magnetic refrigerators and magnetic heat pumps which are referred to interchangeably. Significant progress has been made on the development of engineering prototypes of cryogenic, nonregenerative magnetic refrigerators utilizing conductive heat transfer in the 0.1 K to 20 K temperature range. Advances have also been made in analysis of regenerative magnetic refrigerators and heat pumps utilizing the active magnetic regeneration (AMR) concept. Units based on AMR are being modeled, designed and/or built to operate in various temperature ranges including 1.8-4.5 K, 4-15 K, 15-85 K, and 270-320 K. The near room temperature units have been scaled to 50 kW as both refrigerators and heat pumps. The progress of magnetic refrigeration over the last three years is summarized and discussed

  6. Magnetic levitation Maglev technology and applications

    CERN Document Server

    Han, Hyung-Suk

    2016-01-01

    This book provides a comprehensive overview of magnetic levitation (Maglev) technologies, from fundamental principles through to the state-of-the-art, and describes applications both realised and under development. It includes a history of Maglev science and technology showing the various milestones in its advancement. The core concepts, operating principles and main challenges of Maglev applications attempted across various fields are introduced and discussed. The principle difficulties encountered when applying Maglev technology to different systems, namely air gap control and stabilization, are addressed in detail. The book describes how major advancements in linear motor and magnet technologies have enabled the development of the linear-motor-powered Maglev train, which has a high speed advantage over conventional wheeled trains and has the potential to reach speed levels achieved by aircraft. However, many expect that Maglev technology to be a green technology that is applied not only in rail transportat...

  7. Effects of axial magnetic field on the electronic and optical properties of boron nitride nanotube

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2011-07-01

    The splitting of band structure and absorption spectrum, for boron nitride nanotubes (BNNTs) under axial magnetic field, is studied using the tight binding approximation. It is found that the band splitting ( ΔE) at the Γ point is linearly proportional to the magnetic field ( Φ/Φ0). Our results indicate that the splitting rate νii, of the two first bands nearest to the Fermi level, is a linear function of n -2 for all (n,0) zigzag BNNTs. By investigation of the dependence of band structure and absorption spectrum to the magnetic field, we found that absorption splitting is equal to band splitting and the splitting rate of band structure can be used to determine the splitting rate of the absorption spectrum.

  8. Technology-development needs for magnetic fusion

    International Nuclear Information System (INIS)

    Stacey, W.M. Jr.; Baker, C.C.; Conn, R.W.; Krakowski, R.A.; Steiner, D.; Thomassen, K.I.

    1983-03-01

    The technology-development needs for magnetic fusion have been identified from an assessment of the conceptual design studies which have been performed. A summary of worldwide conceptual design effort is presented. The relative maturity of the various confinement concepts and the intensity and continuity of the design efforts are taken into account in identifying technology development needs. A major conclusion of this study is that there is a high degree of commonality among the technology requirements identified for the various confinement concepts

  9. Transport properties of finite carbon nanotubes under electric and magnetic fields

    International Nuclear Information System (INIS)

    Li, T S; Lin, M F

    2006-01-01

    Electronic and transport properties of finite carbon nanotubes subject to the influences of a transverse electric field and a magnetic field with varying polar angles are studied by the tight-binding model. The external fields will modify the state energies, destroy the state degeneracy, and modulate the energy gap. Both the state energy and the energy gap exhibit rich dependence on the field strength, the magnetic field direction, and the types of carbon nanotubes. The semiconductor-metal transition would be allowed for certain field strengths and magnetic field directions. The variations of state energies with the external fields will also be reflected in the electrical and thermal conductance. The number, the heights, and the positions of the conductance peaks are strongly dependent on the external fields. The heights of the electrical and thermal conductance peaks display a quantized behaviour, while that of the Peltier coefficient does not. Finally, it is found that the validity of the Wiedemann-Franz law depends upon the temperature, the field strength, the electronic structure, and the chemical potential

  10. Properties of Cs-intercalated single wall carbon nanotubes investigated by 133Cs Nuclear Magnetic resonance

    KAUST Repository

    Schmid, Marc R.

    2012-11-01

    In the present study, we investigated Cs-intercalated single wall carbon nanotubes (SWCNTs) using 133Cs Nuclear Magnetic resonance. We show that there are two types of Cs cations depending on the insertion level. Indeed, at low concentrations, Static spectra analysis shows that the Cs (α)+ species are fully ionized, i.e. α equal ca.1, while at higher concentrations a second paramagnetically shifted line appears, indicating the formation of Cs (β)+ ions with β < α ∼ +1. At low concentrations and low temperatures the Cs (α)+ ions exhibit a weak hyperfine coupling to the SWCNT conduction electrons, whereas, at higher temperatures, a thermally activated slow-motion diffusion process of the Cs (α)+ ions occurs along the interstitial channels present within the carbon nanotube bundles. At high concentrations, the Cs (β)+ ions seem to occupy well defined positions relative to the carbon lattice. As a matter of fact, the Korringa relaxation behavior suggests a strong hyperfine coupling between Cs nuclei and conduction electrons in the carbon nanotubes and a partial charge transfer, which suggest a plausible Cs(6s)-C(2p) hybridization. © 2012 Elsevier Ltd. All rights reserved.

  11. Flutter instability of cantilevered carbon nanotubes caused by magnetic fluid flow subjected to a longitudinal magnetic field

    Science.gov (United States)

    Sadeghi-Goughari, Moslem; Jeon, Soo; Kwon, Hyock-Ju

    2018-04-01

    CNT (Carbon nanotube)-based fluidic systems hold a great potential for emerging medical applications such as drug delivery for cancer therapy. CNTs can be used to deliver anticancer drugs into a target site under a magnetic field guidance. One of the critical issues in designing such systems is how to avoid the vibration induced by the fluid flow, which is undesirable and may even promote the structural instability. The main objective of the present research is to develop a fluid structure interaction (FSI) model to investigate the flutter instability of a cantilevered CNT induced by a magnetic fluid flow under a longitudinal magnetic field. The CNT is assumed to be embedded in a viscoelastic matrix to consider the effect of biological medium around it. To obtain a dynamical model for the system, the Navier-Stokes theory of magnetic-fluid flow is coupled to the Euler-Bernoulli beam model for CNT. The small size effects of the magnetic fluid and CNT are considered through the small scale parameters including Knudsen number (Kn) and the nonlocal parameter. Then, the extended Galerkin's method is applied to solve the FSI governing equations, and to derive the stability diagrams of the system. Results show how the magnetic properties of the fluid flow have an effect on improving the stability of the cantilevered CNT by increasing the flutter velocity.

  12. Magnetic properties of iron catalyst particles in HiPco single wall carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Bittová, Barbara; Poltierová Vejpravová, Jana; Kalbáč, Martin; Burianová, Simona; Mantlíková, A.; Daniš, S.; Doyle, S.

    2011-01-01

    Roč. 115, č. 35 (2011), s. 17303-17309 ISSN 1932-7447 R&D Projects: GA ČR GAP204/10/1677 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z40400503 Keywords : metal catalyst particles * carbon nanotubes * superparamagnet * core - shell model * inter-particle interactions Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.805, year: 2011 http://pubs.acs.org/doi/abs/10.1021/jp203365g

  13. Magnetic orientation of single-walled carbon nanotubes or their composites using polymer wrapping

    Directory of Open Access Journals (Sweden)

    Hiroaki Yonemura et al

    2008-01-01

    Full Text Available The magnetic orientation of single-walled carbon nanotubes (SWNTs or the SWNT composites wrapped with polymer using poly[2-methoxy-5-(2'-ethylhexyloxy-1,4-phenylene vinylene] (MEHPPV as the conducting polymer were examined. The formation of SWNT/MEHPPV composites was confirmed by examining absorption and fluorescence spectra. The N,N-dimethylformamide solution of SWNT/MEHPPV composites or the aqueous solution of the shortened SWNTs was introduced dropwise onto a mica or glass plate. The magnetic processing of the composites or the SWNTs was carried out using a superconducting magnet with a horizontal direction (8 T. The AFM images indicated that the SWNT/MEHPPV composites or the SWNTs were oriented randomly without magnetic processing, while with magnetic processing (8 T, they were oriented with the tube axis of the composites or the SWNTs parallel to the magnetic field. In polarized absorption spectra of SWNT/MEHPPV composites on glass plates without magnetic processing, the absorbance due to semiconducting SWNT in the near-IR region in horizontal polarized light was almost the same as that in vertical polarized light. In contrast, with magnetic processing (8 T, the absorbance due to semiconducting SWNT in the horizontal polarization direction against the direction of magnetic field was stronger than that in the vertical polarization direction. Similar results were obtained from the polarized absorption spectra for the shortened SWNTs. These results of polarized absorption spectra also support the magnetic orientation of the SWNT/MEHPPV composites or the SWNTs. On the basis of a comparison of the composites and the SWNTs alone, the magnetic orientation of SWNT/MEHPPV composites is most likely ascribable to the anisotropy in susceptibilities of SWNTs.

  14. Bioinspired peptide nanotubes: Deposition technology and physical properties

    International Nuclear Information System (INIS)

    Shklovsky, J.; Beker, P.; Amdursky, N.; Gazit, E.; Rosenman, G.

    2010-01-01

    Proteins and peptides have the intrinsic ability to self-assemble into elongated solid nanofibrils, which give rise to amyloid progressive neurodegenerative diseases (Alzheimer's, Parkinson, etc.). It has been found that of the core recognition motif of Aβ peptide is the diphenylalanine element. The diphenylalanine peptide can self-assemble into well-ordered peptide nanotubes (PNT). In this paper we report on our newly developed process-vapor deposition of PNT and 'bottom-up' nanotechnological techniques of PNT patterning. Study of several physical properties of PNT such as optical and electrochemical are presented. The results may lead to the development of a new generation of PNT-based bioinspired functional nanodevices.

  15. Magnetically anisotropic additive for scalable manufacturing of polymer nanocomposite: iron-coated carbon nanotubes

    International Nuclear Information System (INIS)

    Yamamoto, Namiko; Manohara, Harish; Platzman, Ellen

    2016-01-01

    Novel nanoparticles additives for polymer nanocomposites were prepared by coating carbon nanotubes (CNTs) with ferromagnetic iron (Fe) layers, so that their micro-structures can be bulk-controlled by external magnetic field application. Application of magnetic fields is a promising, scalable method to deliver bulk amount of nanocomposites while maintaining organized nanoparticle assembly throughout the uncured polymer matrix. In this work, Fe layers (∼18 nm thick) were deposited on CNTs (∼38 nm diameter and ∼50 μm length) to form thin films with high aspect ratio, resulting in a dominance of shape anisotropy and thus high coercivity of ∼50–100 Oe. The Fe-coated CNTs were suspended in water and applied with a weak magnetic field of ∼75 G, and yet preliminary magnetic assembly was confirmed. Our results demonstrate that the fabricated Fe-coated CNTs are magnetically anisotropic and effectively respond to magnetic fields that are ∼10 3 times smaller than other existing work (∼10 5 G). We anticipate this work will pave the way for effective property enhancement and bulk application of CNT–polymer nanocomposites, through controlled micro-structure and scalable manufacturing. (paper)

  16. In vivo biodistribution and biological impact of injected carbon nanotubes using magnetic resonance techniques

    Directory of Open Access Journals (Sweden)

    Achraf Al Faraj

    2011-02-01

    Full Text Available Achraf Al Faraj1,2, Florence Fauvelle3, Nathalie Luciani4, Ghislaine Lacroix5, Michael Levy4, Yannick Crémillieux1, Emmanuelle Canet-Soulas1Université Lyon1, Créatis-LRMN, Lyon, France; 2King Saud University, College of Applied Medical Sciences, Radiological Sciences Department, Riyadh, Kingdom of Saudi Arabia; 3CRSSA, Biophysique Cellulaire et Moléculaire, Laboratoire de RMN, La Tronche, France; 4Université Paris7-Paris Diderot, Matières et Systèmes Complexes, Paris, France; 5Institut National de l’Environnement et des Risques Industriels, Verneuil-en-Halatte, FranceBackground: Single-walled carbon nanotubes (SWCNT hold promise for applications as contrast agents and target delivery carriers in the field of nanomedicine. When administered in vivo, their biodistribution and pharmacological profile needs to be fully characterized. The tissue distribution of carbon nanotubes and their potential impact on metabolism depend on their shape, coating, and metallic impurities. Because standard radiolabeled or fluorescently-labeled pharmaceuticals are not well suited for long-term in vivo follow-up of carbon nanotubes, alternative methods are required.Methods: In this study, noninvasive in vivo magnetic resonance imaging (MRI investigations combined with high-resolution magic angle spinning (HR-MAS, Raman spectroscopy, iron assays, and histological analysis ex vivo were proposed and applied to assess the biodistribution and biological impact of intravenously injected pristine (raw and purified and functionalized SWCNT in a 2-week longitudinal study. Iron impurities allowed raw detection of SWCNT in vivo by susceptibility-weighted MRI.Results: A transitional accumulation in the spleen and liver was observed by MRI. Raman spectroscopy, iron assays, and histological findings confirmed the MRI readouts. Moreover, no acute toxicological effect on the liver metabolic profile was observed using the HR-MAS technique, as confirmed by quantitative real

  17. Magnetization measurement of single La0.67Ca0.33MnO3 nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator

    International Nuclear Information System (INIS)

    Antonio, D.; Dolz, M.I.; Pastoriza, H.

    2010-01-01

    Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La 0.67 Ca 0.33 MnO 3 . The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant k M of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H>>2K/M the magnetization is almost parallel to the applied magnetic field and for H<<2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition from one regime to the other, accompanied by a peak in the energy dissipation.

  18. Determination of puerarin in rat plasma using PEGylated magnetic carbon nanotubes by high performance liquid chromatography.

    Science.gov (United States)

    Yu, Panfeng; Wang, Qi; Ma, Hongwei; Wu, Ji; Shen, Shun

    2014-05-15

    This paper described a novel application of PEGylated magnetic carbon nanotubes as solid-phase extraction nanosorbents for the determination of puerarin in rat plasma by high performance liquid chromatography (HPLC). A solvothermal method was employed for the synthesis of monodisperse magnetites anchored onto multi-walled carbon nanotubes (MWCNTs@Fe3O4). In order to enhance the water solubility of MWCNTs@Fe3O4 that ensured sufficient contact between nanosorbents and analytes in the sampling procedure, the obtained nanomaterials were further noncovalently functionalized using a phospholipids-polyethylene glycol (DSPE-PEG). The PEGylated MWCNTs@Fe3O4 nanomaterials had an extremely large surface area and exhibit a strong interaction capability for puerarin with π-π stacking interactions. The captured puerarin/nanosorbents were easily isolated from the plasma by placing a magnet, and desorbed by acetonitrile. The experimental variables affecting the extraction efficiency were investigated. The calibration curve of puerarin was linear from 0.01 to 20 μg/ml, and the limit of detection was 0.005 μg/ml. The precisions ranged from 2.7% to 3.5% for within-day measurement, and for between-day variation was in the range of 3.1-5.9%. The method recoveries were acquired from 95.2% to 98.0%. Moreover, the analytical performance obtained by PEGylated magnetic MWCNTs was also compared with that of magnetic MWCNTs. All results showed that our proposed method was an excellent alternative for the analysis of puerarin in rat plasma. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Optical absorption of zigzag single walled boron nitride nanotubes in axial magnetic field

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2013-11-01

    We have investigated the effect of axial magnetic field on the band structure, dipole matrix elements and absorption spectrum in different energy ranges, using tight binding approximation. It is found that magnetic field breaks the degeneracy in the band structure and creates new allowed transitions in the dipole matrix which leads to creation of new peaks in the absorption spectrum. It is found that, unlike to CNTs which show metallic-semiconductor transition, the BNNTs remain semiconductor in any magnetic field strength. By calculation the diameter dependence of peak positions, we found that the positions of three first peaks in the lower energy region (E <5.3 eV) are proportional to n-2. In the middle energy region (7 < E < 7.5 eV) all (n, 0) zigzag BNNTs, with even and odd nanotube index, have two distinct peaks in the absence of magnetic field which these peaks may be used to identify zigzag BNNTs from other tube chiralities. For odd (even) tubes, in the middle energy region, applying the magnetic field leads to splitting of these two peaks into three (five) distinct peaks.

  20. Magnetic properties of a single iron atomic chain encapsulated in armchair carbon nanotubes: A Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Masrour, R., E-mail: rachidmasrour@hotmail.com [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63, 46000 Safi (Morocco); Jabar, A. [Laboratory of Materials, Processes, Environment and Quality, Cady Ayyed University, National School of Applied Sciences, PB 63, 46000 Safi (Morocco); Hamedoun, M. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Benyoussef, A. [Institute of Nanomaterials and Nanotechnologies, MAScIR, Rabat (Morocco); Hassan II Academy of Science and Technology, Rabat (Morocco); Hlil, E.K. [Institut Néel, CNRS, Université Grenoble Alpes, 25 rue des Martyrs BP 166, 38042 Grenoble cedex 9 (France)

    2017-06-15

    Highlights: • Magnetic properties of Fe atom chain wrapped in armchair carbon nanotubes have been studied. • Transition temperature of iron and carbon have been calculated using Monte Carlo simulations. • The multiples magnetic hysteresis have been found. - Abstract: The magnetic properties have been investigated of FeCu{sub x}C{sub 1−x} for a Fe atom chain wrapped in armchair (N,N) carbon nanotubes (N = 4,6,8,10,12) diluted by Cu{sup 2+} ions using Monte Carlo simulations. The thermal total magnetization and magnetic susceptibility are found. The reduced transition temperatures of iron and carbon have been calculated for different N and the exchange interactions. The total magnetization is obtained for different exchange interactions and crystal field. The Magnetic hysteresis cycles are obtained for different N, the reduced temperatures and exchange interactions. The multiple magnetic hysteresis is found. This system shows it can be used as magnetic nanostructure possessing potential current and future applications in permanent magnetism, magnetic recording and spintronics.

  1. Nanomanipulation and Lithography: The Building (and Modeling) of Carbon Nanotube Magnetic Tunnel Junctions

    Science.gov (United States)

    Louie, Richard Nam

    2002-12-01

    Aircraft fuselages suffer alternating stress during takeoffs and landings, and fatigue cracks begin to grow, usually at rivet holes. The detection of these fatigue cracks under installed fasteners in aging aircraft is a major goal of the nondestructive evaluation (NDE) community. The use of giant magnetoresistance (GMR) sensors in electromagnetic (EM) NDE has been increasing rapidly. For example, here at Langley Research Center, a Rotating Probe System (RPS) containing a GMR element has been incorporated into a product to detect deeply buried flaws in aerospace structures. In order to advance this eddy current probe application and many similar ones, research to create smaller, more sensitive and energy-efficient EM sensors has been aggressively pursued. Recent theoretical and experimental work on spin coherent transport supports the feasibility of carbon nanotube (CNT) based magnetic tunnel junctions. In this study, a spatial filtering scheme is presented that improves the signal to noise ratio of the RPS and does not significantly impact the number of false alarms. Signals due to buried flaws occur at higher frequencies than do signals due to rivet tilt or probe misalignment, and the strategy purposefully targets this fact. Furthermore, the spatial filtering scheme exploits decreases in the probe output that are observed immediately preceding and following the peak in output due to a fatigue crack. Using the new filters, an enhanced probability of flaw detection is expected. In the future, even tinier, more sensitive, low-power sensors are envisioned for the rotating probe and other nondestructive inspection systems. These may be comprised of single-walled carbon nanotubes (SWCNTs) that connect two ferromagnetic (FM) electrodes. Theoretical work has been done at Langley to model the electrical and magnetoconductance behavior of such junctions, for systems containing short "armchair" nanotubes. The present work facilitates the modeling of more realistic system

  2. Multifunctional nanocomposite based on halloysite nanotubes for efficient luminescent bioimaging and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Zhou T

    2016-09-01

    Full Text Available Tao Zhou,1 Lei Jia,1 Yi-Feng Luo,2 Jun Xu,1 Ru-Hua Chen,2 Zhi-Jun Ge,2 Tie-Liang Ma,2 Hong Chen,2 Tao-Feng Zhu2 1Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo, Henan, 2The Affiliated Yixing Hospital of Jiangsu University, Yixing, Jiangsu, People’s Republic of China Abstract: A novel multifunctional halloysite nanotube (HNT-based Fe3O4@HNT-polyethyleneimine-Tip-Eu(dibenzoylmethane3 nanocomposite (Fe-HNT-Eu NC with both photoluminescent and magnetic properties was fabricated by a simple one-step hydrothermal process combined with the coupling grafting method, which exhibited high suspension stability and excellent photophysical behavior. The as-prepared multifunctional Fe-HNT-Eu NC was characterized using various techniques. The results of cell viability assay, cell morphological observation, and in vivo toxicity assay indicated that the NC exhibited excellent biocompatibility over the studied concentration range, suggesting that the obtained Fe-HNT-Eu NC was a suitable material for bioimaging and biological applications in human hepatic adenocarcinoma cells. Furthermore, the biocompatible Fe-HNT-Eu NC displayed superparamagnetic behavior with high saturation magnetization and also functioned as a magnetic resonance imaging (MRI contrast agent in vitro and in vivo. The results of the MRI tests indicated that the Fe-HNT-Eu NC can significantly decrease the T2 signal intensity values of the normal liver tissue and thus make the boundary between the normal liver and transplanted cancer more distinct, thus effectively improving the diagnosis effect of cancers. Keywords: halloysite nanotube, lanthanide complex, iron oxide, luminescence, contrast agent

  3. Magnetically responsive polypyrrole nanotubes using Ce(III)-stabilized maghemite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Esman, Natasha; Haviv, Amit; Lellouche, Jean-Paul, E-mail: lellouj@biu.ac.il [Department of Chemistry, Nanomaterials Research Center, Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan 52900 (Israel)

    2011-07-15

    Nanocomposites (NCs) that are made magnetically responsive in controlled conditions attract continuing interest for their added magnetic properties. In this study, we report on the preparation and full characterization of a multifunctional NC composed of magnetic {gamma}-Fe{sub 2}O{sub 3} nanoparticles (NPs) covalently attached to the surface of polyaminated (polyNH{sub 2}) poly(2,6-di-pyrrol-1-yl-hexanoic acid) (pDPL) nanotubes (NTs). Such a hybrid conducting polymer iron oxide maghemite {gamma}-Fe{sub 2}O{sub 3}-pDPL NC built specifically on covalent bonding has never been reported. The maghemite {gamma}-Fe{sub 2}O{sub 3} NPs were prepared using an innovative ultrasound-assisted Ce{sup 3+} doping process, resulting in polycarboxylation of the NP surface useful for control of aggregation and derivatization of functionality. The second component of the NC, i.e. polyNH{sub 2}-modified pDPL NTs, was prepared from an acid functional pyrrole species followed by amine modification. The resulting innovative {gamma}-Fe{sub 2}O{sub 3}-pDPL NC can be viewed as a multifunctional nanomaterial since it possesses both types of derivatization, i.e. polyCOOH (NPs) and polyNH{sub 2} (NTs) combined with magnetic responsivity.

  4. Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

    KAUST Repository

    Abou-Hamad, E; Goze-Bac, C; Nitze, F; Schmid, M; Aznar, R; Mehring, M; Wå gberg, T

    2011-01-01

    We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The 'metallization' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

  5. Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

    KAUST Repository

    Abou-Hamad, E

    2011-05-24

    We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The \\'metallization\\' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

  6. SSC [Superconducting Super Collider] magnet technology

    International Nuclear Information System (INIS)

    Taylor, C.

    1987-09-01

    To minimize cost of the SSC facility, small-bore high field dipole magnets have been developed;some of the new technology that has been developed at several U.S. national laboratories and in industry is summarized. Superconducting wire with high J/sub c/ and filaments as small as 5μm diameter is not produced iwht mechanical properties suitable for reliable cable production. A variety of collar designs of both aluminum and stainless steel have been used in model magnets. A low-heat leak post-type cryostat support system is used and a system for accurate alignment of coil-collar-yoke in the cryostat has been developed. Model magnets of 1-m, 1.8 m, 4.5 m, and 17 m lengths have been build during the past two years. 23 refs., 5 figs., 2 tabs

  7. Vibration Reduction System Using Magnetic Suspension Technology

    Directory of Open Access Journals (Sweden)

    Spychała Jarosław

    2015-01-01

    Full Text Available The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

  8. Optimization on microwave absorbing properties of carbon nanotubes and magnetic oxide composite materials

    Science.gov (United States)

    Mingdong, Chen; Huangzhong, Yu; Xiaohua, Jie; Yigang, Lu

    2018-03-01

    Based on the physical principle of interaction between electromagnetic field and the electromagnetic medium, the relationship between microwave absorbing coefficient (MAC) and the electromagnetic parameters of materials was established. With the composite materials of nickel ferrite (NiFe2O4), carbon nanotubes (CNTs) and paraffin as an example, optimization on absorbing properties of CNTs/magnetic oxide composite materials was studied at the frequency range of 2-18 GHz, and a conclusion is drawn that the MAC is the biggest at the same frequency, when the CNTs is 10 wt% in the composite materials. Through study on the relationship between complex permeability and MAC, another interesting conclusion is drawn that MAC is obviously affected by the real part of complex permeability, and increasing real part of complex permeability is beneficial for improving absorbing properties. The conclusion of this paper can provide a useful reference for the optimization research on the microwave absorbing properties of CNTs/ferrite composite materials.

  9. Extraction of ochratoxin A in red wine with dopamine-coated magnetic multi-walled carbon nanotubes.

    Science.gov (United States)

    Wan, Hong; Zhang, Bo; Bai, Xiao-Lin; Zhao, Yan; Xiao, Meng-Wei; Liao, Xun

    2017-10-01

    A new, rapid, green, and cost-effective magnetic solid-phase extraction of ochratoxin A from red wine samples was developed using polydopamine-coated magnetic multi-walled carbon nanotubes as the absorbent. The polydopamine-coated magnetic multi-walled carbon nanotubes were fabricated with magnetic multi-walled carbon nanotubes and dopamine by an in situ oxidative self-polymerization approach. Transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy and vibrating sample magnetometry were used to characterize the absorbents. Ochratoxin A was quantified with high-performance liquid chromatography coupled with fluorescence detection, with excitation and emission wavelengths of 338 and 455 nm, respectively. The conditions affecting the magnetic solid-phase extraction procedure, such as pH, extraction solution, extraction time, absorbent amount, desorption solution and desorption time were investigated to obtain the optimal extraction conditions. Under the optimized conditions, the extraction recovery was 91.8-104.5% for ochratoxin A. A linear calibration curve was obtained in the range of 0.1-2.0 ng/mL. The limit of detection was 0.07 ng/mL, and the limit of quantitation was 0.21 ng/mL. The recoveries of ochratoxin A for spiked red wine sample ranged from 95.65 to 100.65% with relative standard deviation less than 8%. The polydopamine-coated magnetic multi-walled carbon nanotubes showed a high affinity toward ochratoxin A, allowing selective extraction and quantification of ochratoxin A from complex sample matrixes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis of carbon nanotubes using fluidized bed technology

    CSIR Research Space (South Africa)

    Swartbooi, AM

    2008-11-01

    Full Text Available virgin plastics as well as a carbonaceous gas using fluidized bed technology. Current investigations are underway to test various factors involved with the CNT growth and production. An understanding of these factors and their interactions could provide...

  11. Multifunctional nanocomposite based on halloysite nanotubes for efficient luminescent bioimaging and magnetic resonance imaging.

    Science.gov (United States)

    Zhou, Tao; Jia, Lei; Luo, Yi-Feng; Xu, Jun; Chen, Ru-Hua; Ge, Zhi-Jun; Ma, Tie-Liang; Chen, Hong; Zhu, Tao-Feng

    A novel multifunctional halloysite nanotube (HNT)-based Fe 3 O 4 @HNT-polyethyleneimine-Tip-Eu(dibenzoylmethane) 3 nanocomposite (Fe-HNT-Eu NC) with both photoluminescent and magnetic properties was fabricated by a simple one-step hydrothermal process combined with the coupling grafting method, which exhibited high suspension stability and excellent photophysical behavior. The as-prepared multifunctional Fe-HNT-Eu NC was characterized using various techniques. The results of cell viability assay, cell morphological observation, and in vivo toxicity assay indicated that the NC exhibited excellent biocompatibility over the studied concentration range, suggesting that the obtained Fe-HNT-Eu NC was a suitable material for bioimaging and biological applications in human hepatic adenocarcinoma cells. Furthermore, the biocompatible Fe-HNT-Eu NC displayed superparamagnetic behavior with high saturation magnetization and also functioned as a magnetic resonance imaging (MRI) contrast agent in vitro and in vivo. The results of the MRI tests indicated that the Fe-HNT-Eu NC can significantly decrease the T 2 signal intensity values of the normal liver tissue and thus make the boundary between the normal liver and transplanted cancer more distinct, thus effectively improving the diagnosis effect of cancers.

  12. Electronic structure and magnetic properties of substitutional transition-metal atoms in GaN nanotubes

    International Nuclear Information System (INIS)

    Zhang Min; Shi Jun-Jie

    2014-01-01

    The electronic structure and magnetic properties of the transition-metal (TM) atoms (Sc—Zn, Pt and Au) doped zigzag GaN single-walled nanotubes (NTs) are investigated using first-principles spin-polarized density functional calculations. Our results show that the bindings of all TM atoms are stable with the binding energy in the range of 6–16 eV. The Sc- and V-doped GaN NTs exhibit a nonmagnetic behavior. The GaN NTs doped with Ti, Mn, Ni, Cu and Pt are antiferromagnetic. On the contrary, the Cr-, Fe-, Co-, Zn- and Au-doped GaN NTs show the ferromagnetic characteristics. The Mn- and Co-doped GaN NTs induce the largest local moment of 4μ B among these TM atoms. The local magnetic moment is dominated by the contribution from the substitutional TM atom and the N atoms bonded with it. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Longitudinal waves in carbon nanotubes in the presence of transverse magnetic field and elastic medium

    Science.gov (United States)

    Liu, Hu; Liu, Hua; Yang, Jialing

    2017-09-01

    In the present paper, the coupling effect of transverse magnetic field and elastic medium on the longitudinal wave propagation along a carbon nanotube (CNT) is studied. Based on the nonlocal elasticity theory and Hamilton's principle, a unified nonlocal rod theory which takes into account the effects of small size scale, lateral inertia and radial deformation is proposed. The existing rod theories including the classic rod theory, the Rayleigh-Love theory and Rayleigh-Bishop theory for macro solids can be treated as the special cases of the present model. A two-parameter foundation model (Pasternak-type model) is used to represent the elastic medium. The influence of transverse magnetic field, Pasternak-type elastic medium and small size scale on the longitudinal wave propagation behavior of the CNT is investigated in detail. It is shown that the influences of lateral inertia and radial deformation cannot be neglected in analyzing the longitudinal wave propagation characteristics of the CNT. The results also show that the elastic medium and the transverse magnetic field will also affect the longitudinal wave dispersion behavior of the CNT significantly. The results obtained in this paper are helpful for understanding the mechanical behaviors of nanostructures embedded in an elastic medium.

  14. Simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma.

    Science.gov (United States)

    Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

    2012-02-02

    Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices(1-4). Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT (5), narrow the diameter distribution of metallic catalyst particles and carbon nanotubes (6), and change the ratio of metallic and semiconducting carbon nanotubes (7), as well as lead to graphene synthesis (8). Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the

  15. Isotactic polypropylene/carbon nanotube composites prepared by latex technology. Thermal analysis of carbon nanotube-induced nucleation

    NARCIS (Netherlands)

    Miltner, H.E.; Grossiord, N.; Lu, K.; Loos, J.; Koning, C.E.; Van Mele, B.

    2008-01-01

    During nonisothermal crystallization of highly dispersed polypropylene/carbon nanotube (CNT) composites, considerable heterogeneous nucleation is observed to an extent scaling with the CNT surface area. Saturation occurs at higher loadings, reaching a plateau value for the crystallization onset

  16. Detection of p53 Gene by Using Genomagnetic Assay Combined with Carbon Nanotube Modified Disposable Sensor Technology

    Czech Academy of Sciences Publication Activity Database

    Congur, G.; Plucnara, Medard; Erdem, A.; Fojta, Miroslav

    2015-01-01

    Roč. 27, č. 7 (2015), s. 1579-1586 ISSN 1040-0397 R&D Projects: GA ČR GAP206/11/1638 Institutional support: RVO:68081707 Keywords : p53 Gene * Carbon nanotubes * Magnetic particles Subject RIV: BO - Biophysics Impact factor: 2.471, year: 2015

  17. One-dimensional BiFeO{sub 3} nanotubes: Preparation, characterization, improved magnetic behaviors, and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lei [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China); School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China); Sui, Wenbo; Dong, Chunhui; Zhang, Chao [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China); Jiang, Changjun, E-mail: 779322052@qq.com [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China)

    2016-10-30

    Highlights: • We present a fabrication method of one-dimensional BFO nanotubes prepared using a sol–gel-based electrospinning process followed by thermal treatment. • By compared with BiFeO{sub 3} bulks, enhanced room temperature ferromagnetism has been successfully realized in BFO nanotubes. • The impacts of processing temperature on the final microscopic structure and component are characterized in detail. • The existence of plentiful oxygen vacancies will play a key role in terms of enhanced ferromagnetism. - Abstract: With the progress of science and technology, the growing demands for practical applications make low-dimensional multiferroics more appealing in areas such as chemical and bio-sensors, nanoelectronic, high-density data storage devices. One-dimensional BiFeO{sub 3} nanotubes were successfully synthesized by sol–gel-based electrospinning process. The images of scanning electron microscopy and transmission electron microscopy collectively demonstrate that BiFeO{sub 3} nanotubes with long slender structure and virtually uniform diameter of approximately 100 nm were observed at 500 °C annealing temperature. By compared with BiFeO{sub 3} bulks observed at 800 °C annealing temperature, enhanced room temperature ferromagnetism was successfully realized in BiFeO{sub 3} nanotubes at room temperature. The results of electron spin resonance measurement further confirm that ferromagnetic resonances were detected in BiFeO{sub 3} nanotubes at different temperature. X-ray photoelectron spectroscopy study proves the existence of plentiful oxygen vacancies in BiFeO{sub 3} nanotubes, which will play a key role in terms of enhanced ferromagnetism. The results will contribute to expand the applications of BiFeO{sub 3} into the new field of spintronic devices and high-density data storage media.

  18. Domain wall manipulation in magnetic nanotubes induced by electric current pulses

    International Nuclear Information System (INIS)

    Otálora, J A; López-López, J A; Landeros, P; Núñez, A S

    2012-01-01

    We propose that the injection of electric currents can be used to independently manipulate the position and chirality of vortex-like domain walls in metallic ferromagnetic nanotubes. We support this proposal upon theoretical and numerical assessment of the magnetization dynamics driven by such currents. We show that proper interplay between the tube geometry, magnitude of the electric current and the duration of a current pulse, can be used to manipulate the position, velocity and chirality of a vortex domain wall. Our calculations suggest that domain wall velocities greater than 1 km s -1 can be achieved for tube diameters of the order of 30 nm and increasing with it. We also find that the transition from steady to precessional domain wall motion occurs for very high electric current densities, of the order of 10 13 A m -2 . Furthermore, the great stability displayed by such chiral magnetic configurations, and the reduced Ohmic loses provided by the current pulses, lead to highly reproducible and efficient domain wall reversal mechanisms.

  19. Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    KAUST Repository

    Mahfouz, Remi

    2015-09-18

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(EF).

  20. Recent development of carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Yamabe, Tokio [Div. of Molecular Engineering, Kyoto Univ. (Japan); [Inst. for Fundamental Chemistry, Kyoto (Japan)

    1995-03-15

    Recent developments of carbon nanotubes are reviewed. Analytical solutions for the electronic structure of carbon nanotube on the basis of thight-binding approximation are presented and interpreted using the concepts of crystal orbital. The electronic properties of actual carbon nanotubes are presented. The electronic structures of carbon nanotubes in the presence of magnetic fiels are also summerized. (orig.)

  1. Efficient removal of cadmium using magnetic multiwalled carbon nanotube nanoadsorbents: equilibrium, kinetic, and thermodynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Pashai Gatabi, Maliheh; Milani Moghaddam, Hossain, E-mail: Milani@umz.ac.ir [University of Mazandaran, Soid State Physics Department (Iran, Islamic Republic of); Ghorbani, Mohsen [Babol Noshirvani University of Technology, Chemical Engineering Department (Iran, Islamic Republic of)

    2016-07-15

    Adsorptive potential of maghemite decorated multiwalled carbon nanotubes (MWCNTs) for the removal of cadmium ions from aqueous solution was investigated. The magnetic nanoadsorbent was synthesized using a versatile and cost effective chemical route. Structural, magnetic and surface charge properties of the adsorbent were characterized using FTIR, XRD, TEM, VSM analysis and pH{sub PZC} determination. Batch adsorption experiments were performed under varied system parameters such as pH, contact time, initial cadmium concentration and temperature. Highest cadmium adsorption was obtained at pH 8.0 and contact time of 30 min. Adsorption behavior was kinetically studied using pseudo first-order, pseudo second-order, and Weber–Morris intra particle diffusion models among which data were mostly correlated to pseudo second-order model. Adsorbate-adsorbent interactions as a function of temperature was assessed by Langmuir, Freundlich, Dubinin–Radushkevich (D-R) and Temkin isotherm models from which Freundlich model had the highest consistency with the data. The adsorption capacity increased with increasing temperature and maximum Langmuir’s adsorption capacity was found to be 78.81 mg g{sup −1} at 298 K. Thermodynamic parameters and activation energy value suggest that the process of cadmium removal was spontaneous and physical in nature, which lead to fast kinetics and high regeneration capability of the nanoadsorbent. Results of this work are of great significance for environmental applications of magnetic MWCNTs as promising adsorbent for heavy metals removal from aqueous solutions.Graphical Abstract.

  2. Theoretical exploration of structural, electro-optical and magnetic properties of gallium-doped silicon carbide nanotubes

    Science.gov (United States)

    Behzad, Somayeh; Chegel, Raad; Moradian, Rostam; Shahrokhi, Masoud

    2014-09-01

    The effects of gallium doping on the structural, electro-optical and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) are investigated by using spin-polarized density functional theory. It is found from the calculation of the formation energies that gallium substitution for silicon atom is preferred. Our results show that gallium substitution at either single carbon or silicon atom site in SiCNT could induce spontaneous magnetization. The optical studies based on dielectric function indicate that new transition peaks and a blue shift are observed after gallium doping.

  3. Fabrication of Nickel Nanotube Using Anodic Oxidation and Electrochemical Deposition Technologies and Its Hydrogen Storage Property

    Directory of Open Access Journals (Sweden)

    Yan Lv

    2016-01-01

    Full Text Available Electrochemical deposition technique was utilized to fabricate nickel nanotubes with the assistance of AAO templates. The topography and element component of the nickel nanotubes were characterized by TEM and EDS. Furthermore, the nickel nanotube was made into microelectrode and its electrochemical hydrogen storage property was studied using cyclic voltammetry. The results showed that the diameter of nickel nanotubes fabricated was around 20–100 mm, and the length of the nanotube could reach micron grade. The nickel nanotubes had hydrogen storage property, and the hydrogen storage performance was higher than that of nickel powder.

  4. Application of carbon nanotube technology for removal of contaminants in drinking water: A review

    International Nuclear Information System (INIS)

    Upadhyayula, Venkata K.K.; Deng, Shuguang; Mitchell, Martha C.; Smith, Geoffrey B.

    2009-01-01

    Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM), and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.

  5. Effect of Longitudinal Magnetic Field on Vibration Characteristics of Single-Walled Carbon Nanotubes in a Viscoelastic Medium

    Science.gov (United States)

    Zhang, D. P.; Lei, Y.; Shen, Z. B.

    2017-12-01

    The effect of longitudinal magnetic field on vibration response of a sing-walled carbon nanotube (SWCNT) embedded in viscoelastic medium is investigated. Based on nonlocal Euler-Bernoulli beam theory, Maxwell's relations, and Kelvin viscoelastic foundation model, the governing equations of motion for vibration analysis are established. The complex natural frequencies and corresponding mode shapes in closed form for the embedded SWCNT with arbitrary boundary conditions are obtained using transfer function method (TFM). The new analytical expressions for the complex natural frequencies are also derived for certain typical boundary conditions and Kelvin-Voigt model. Numerical results from the model are presented to show the effects of nonlocal parameter, viscoelastic parameter, boundary conditions, aspect ratio, and strength of the magnetic field on vibration characteristics for the embedded SWCNT in longitudinal magnetic field. The results demonstrate the efficiency of the proposed methods for vibration analysis of embedded SWCNTs under magnetic field.

  6. Shape anisotropy and hybridization enhanced magnetization in nanowires of Fe/MgO/Fe encapsulated in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aryee, Dennis [Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005 (United States); Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251 (United States); Seifu, Dereje, E-mail: dereje.seifu@morgan.edu [Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251 (United States)

    2017-05-01

    Arrays of tunneling magnetoresistance (TMR) nanowires were synthesized for the first time by filling Fe/MgO/Fe inside vertically grown and substrate supported carbon nanotubes. The magnetic properties of nanowires and planar nanoscale thin films of Fe/MgO/Fe showed several similarities, such as two-fold magnetic symmetry and ratio of orbital moment to spin moment. Nanowires of Fe/MgO/Fe showed higher saturation magnetization by a factor of 2.7 compared to planar thin films of Fe/MgO/Fe at 1.5 kOe. The enhanced magnetic properties likely resulted from shape anisotropy of the nanowires and as well as the hybridization that occur between the π- electronic states of carbon and 3d-bands of the Fe-surface.

  7. Anomaly detection using magnetic flux leakage technology

    Energy Technology Data Exchange (ETDEWEB)

    Rempel, Raymond G. [BJ Pipeline Inspection Services, Alberta (Canada)

    2005-07-01

    There are many aspects to properly assessing the integrity of a pipeline. In-line-Inspection (ILI) tools, in particular those that employ the advanced use of Magnetic Flux Leakage (MFL) technology, provide a valuable means of achieving required up-to-date knowledge of a pipeline. More prevalent use of High Resolution MFL In-Line-Inspection tools is growing the knowledge base that leads to more reliable and accurate identification of anomalies in a pipeline, thus, minimizing the need for expensive verification excavations. Accurate assessment of pipeline anomalies can improve the decision making process within an Integrity Management Program and excavation programs can then focus on required repairs instead of calibration or exploratory digs. Utilizing the information from an MFL ILI inspection is not only cost effective but, as well, can also prove to be an extremely valuable building block of a Pipeline Integrity Management Program. (author)

  8. Optimization and evaluation of chelerythrine nanoparticles composed of magnetic multiwalled carbon nanotubes by response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yong [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541014 (China); Yuan, Yulin [Department of Clinical Laboratory, the People' s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi 530021 (China); Zhou, Zhide; Liang, Jintao; Chen, Zhencheng [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541014 (China); Li, Guiyin, E-mail: liguiyin01@163.com [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541014 (China)

    2014-02-15

    In this study, a new chelerythrine nanomaterial targeted drug delivery system (Fe{sub 3}O{sub 4}/MWNTs-CHE) was designed with chelerythrine (CHE) as model of antitumor drug and magnetic multiwalled carbon nanotubes (Fe{sub 3}O{sub 4}/MWNTs) nanocomposites as drug carrier. The process and formulation variables of Fe{sub 3}O{sub 4}/MWNTs-CHE were optimized using response surface methodology (RSM) with a three-level, three-factor Box–Behnken design (BBD). Mathematical equations and response surface plots were used to relate the dependent and independent variables. The experimental results were fitted into second-order response surface model. When Fe{sub 3}O{sub 4}/MWNTs:CHE ratio was 20.6:1, CHE concentration was 172.0 μg/mL, temperature was 34.5 °C, the drug loading content and entrapment efficiency were 3.04 ± 0.17% and 63.68 ± 2.36%, respectively. The optimized Fe{sub 3}O{sub 4}/MWNTs-CHE nanoparticles were characterized by scanning electron microscopy (SEM), Zeta potential, in vitro drug release and MTT assays. The in vitro CHE drug release behavior from Fe{sub 3}O{sub 4}/MWNTs-CHE displayed a biphasic drug release pattern and followed Korsmeyer–Peppas model with Fickian diffusion mechanism for drug release. The results from MTT assays suggested that the Fe{sub 3}O{sub 4}/MWNTs-CHE could effectively inhibit the proliferation of human hepatoma cells (HepG2), which displayed time or concentration-dependent manner. All these preliminary studies were expected to provide a theoretical basis and offer new methods for preparation efficient magnetic targeted drug delivery systems.

  9. Magnetic multiwalled carbon nanotubes as nanocarrier tags for sensitive determination of fetuin in saliva.

    Science.gov (United States)

    Sánchez-Tirado, Esther; González-Cortés, Araceli; Yáñez-Sedeño, Paloma; Pingarrón, José M

    2018-08-15

    This paper reports the development and performance of an electrochemical immunosensor using magnetic multiwalled carbon nanotubes (m-MWCNTs) as nanocarrier tags for the determination of human fetuin A (HFA), a relevant biomarker of obesity, insulin resistance, and type-2 diabetes as well as for pancreatic and liver cancers and inflammatory processes. Screen-printed carbon electrodes were grafted with p-aminobezoic acid and streptavidin was covalently immobilized on the electrode surface. A biotinylated capture antibody was immobilized through streptavidin-biotin interaction and a sandwich assay configuration was implemented using m-MWCNTs conjugated with HRP and anti-HFA antibodies as the detection label. The determination of HFA was accomplished by measuring the current produced by the electrochemical reduction of benzoquinone at -200 mV upon addition of H 2 O 2 as HRP substrate. The prepared m-MWCNTs were characterized by SEM, TEM, XRD and EDS. All the steps involved in the immunosensor preparation were monitored by electrochemical impedance spectroscopy and cyclic voltammetry. A linear calibration plot for HFA was found between 20 and 2000 pg/mL with a LOD value of 16 pg/mL. This performance is notably better than that reported for an ELISA kit and a chronoimpedimetric immunosensor. The favorable contribution of m-MWCNTs in comparison with MWCNTs without incorporated magnetic particles to this excellent analytical performance is also highlighted. The immunosensor selectivity against other proteins and potentially interfering compounds was excellent. In addition, the usefulness of the immunosensor was demonstrated by the analysis of HFA in saliva with minimal sample treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Integrated Magnetic MEMS Relays: Status of the Technology

    Directory of Open Access Journals (Sweden)

    Giuseppe Schiavone

    2014-08-01

    Full Text Available The development and application of magnetic technologies employing microfabricated magnetic structures for the production of switching components has generated enormous interest in the scientific and industrial communities over the last decade. Magnetic actuation offers many benefits when compared to other schemes for microelectromechanical systems (MEMS, including the generation of forces that have higher magnitude and longer range. Magnetic actuation can be achieved using different excitation sources, which create challenges related to the integration with other technologies, such as CMOS (Complementary Metal Oxide Semiconductor, and the requirement to reduce power consumption. Novel designs and technologies are therefore sought to enable the use of magnetic switching architectures in integrated MEMS devices, without incurring excessive energy consumption. This article reviews the status of magnetic MEMS technology and presents devices recently developed by various research groups, with key focuses on integrability and effective power management, in addition to the ability to integrate the technology with other microelectronic fabrication processes.

  11. Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

    Science.gov (United States)

    Im, Owen; Li, Jian; Wang, Mian; Zhang, Lijie Grace; Keidar, Michael

    2012-01-01

    Background Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT), biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan). Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels. Methods Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells) using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT) and without a magnetic field (N-SWCNT) for improving bone regeneration. Results Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment. Conclusion This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite promising for further exploration for bone regeneration. PMID:22619545

  12. Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

    Directory of Open Access Journals (Sweden)

    Im O

    2012-04-01

    Full Text Available Owen Im1, Jian Li2, Mian Wang2, Lijie Grace Zhang2,3, Michael Keidar2,31Department of Biomedical Engineering, Duke University, Durham, NC; 2Department of Mechanical and Aerospace Engineering, 3Institute for Biomedical Engineering and Institute for Nanotechnology, The George Washington University, Washington, DC, USABackground: Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT, biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan. Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels.Methods: Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT and without a magnetic field (N-SWCNT for improving bone regeneration.Results: Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment.Conclusion: This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite

  13. Magnetic field applications in modern technology and medicine

    International Nuclear Information System (INIS)

    Tenforde, T.S.

    1985-05-01

    A brief summary is given of several major applications of magnetism. A description of the range of magnetic field intensities to which humans are exposed in technologies that utilize large stationary magnetic fields is given. 12 refs., 8 figs., 3 tabs

  14. Adsorption behavior of multiwall carbon nanotube/iron oxide magnetic composites for Ni(II) and Sr(II)

    International Nuclear Information System (INIS)

    Chen Changlun; Hu Jun; Shao Dadong; Li Jiaxing; Wang Xiangke

    2009-01-01

    Multiwall carbon nanotube (MWCNT)/iron oxide magnetic composites were prepared, and were characterized by scan electron microscopy using a field emission scanning electron microscope, X-ray diffraction and vibrating sample magnetometer. The adsorptions of Ni(II) and Sr(II) onto MWCNT/iron oxide magnetic composites were studied as a function of pH and ionic strength. The results show that the adsorptions of Ni(II) and Sr(II) on the magnetic composites is strongly dependent on pH and ionic strength. The adsorption capacity of the magnetic composites is much higher than that of MWCNTs and iron oxides. The solid magnetic composites can be separated from the solution by a magnetic process. The Langmuir model fits the adsorption isotherm data of Ni(II) better than the Freundlich model. Results of desorption study shows that Ni(II) adsorbed onto the magnetic composites can be easily desorbed at pH < 2.0. MWCNT/iron oxide magnetic composites may be a promising candidate for pre-concentration and solidification of heavy metal ions and radionuclides from large volumes of aqueous solution, as required for remediation purposes.

  15. Civilian applications for superconducting magnet technology developed for defense

    International Nuclear Information System (INIS)

    Johnson, R.A.; Klein, S.W.; Gurol, H.

    1986-01-01

    Seventy years after its discovery, superconducting technology is beginning to play an important role in the civilian sector. Strategic defense initiative (SDI)-related research in space- and ground-based strategic defense weapons, particularly research efforts utilizing superconducting magnet energy storage, magnetohydrodynamics (MHD), and superconducting pulsed-power devices, have direct applications in the civilian sector as well and are discussed in the paper. Other applications of superconducting magnets, which will be indirectly enhanced by the overall advancement in superconducting technology, include high-energy physics accelerators, magnetic resonance imaging, materials purifying, water purifying, superconducting generators, electric power transmission, magnetically levitated trains, magnetic-fusion power plants, and superconducting computers

  16. Superconducting magnet technology for particle accelerators and detectors seminar

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    This lecture is an introduction to superconducting magnets for particle accelerators and detectors, the aim being to explain the vocabulary and describe the basic technology of modern superconducting magnets, and to explore the limits of the technology. It will include the following: - Why we need superconducting magnets - Properties of superconductors, critical field, critical temperature - Why accelerators need fine filaments and cables; conductor manufacture - Temperature rise and temperature margin: the quench process, training - Quench protection schemes. Protection in the case of the LHC. - Magnets for detectors - The challenges of state-of-the-art magnets for High Energy Physics

  17. The effect of Co content on the structure and the magnetic properties of Co{sub x}Ni{sub 1−x} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qin [Department of Applied Physics, Hebei University of Technology, Tianjin 300401 (China); Wang, Zhi-Jun [Hebei Chemical and Pharmaceutical Vocational Technology College, Shijiazhuang 050026 (China); Wang, Yong-Guo [Department of Public Foundation, Tianjin Youth Professional College, Tianjin 300350 (China); Sun, Hui-Yuan, E-mail: huiyuansun@126.com [College of Physics Science & Information Engineering, Hebei Normal University, Shijiazhuang 050024 (China)

    2016-12-01

    Co{sub x}Ni{sub 1−x} (x=0–0.5) nanotube arrays with different component contents were prepared by Electrodeposition Method. X-ray diffraction (XRD) measurement indicates that low Co content (x≤0.5) does not change their crystal structure. The direction of easy magnetization changes from being parallel with to being perpendicular to the direction of the nanotube axes, with Co content increasing from 0 to 0.5. This study suggests that the drastic change of magnetic anisotropy is attributed to the competition between the shape and magnetocrystalline anisotropies. - Highlights: • Co{sub x}Ni{sub 1–x}(x=0~0.5) nanotube arrays were prepared by a DC electrodeposition method. • The direction of easy magnetization changes with Co content increasing. • It suggests that the competition between shape and magnetocrystalline anisotropies.

  18. Chirality dependence of dipole matrix element of carbon nanotubes in axial magnetic field: A third neighbor tight binding approach

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh

    2014-02-01

    We have studied the electronic structure and dipole matrix element, D, of carbon nanotubes (CNTs) under magnetic field, using the third nearest neighbor tight binding model. It is shown that the 1NN and 3NN-TB band structures show differences such as the spacing and mixing of neighbor subbands. Applying the magnetic field leads to breaking the degeneracy behavior in the D transitions and creates new allowed transitions corresponding to the band modifications. It is found that |D| is proportional to the inverse tube radius and chiral angle. Our numerical results show that amount of filed induced splitting for the first optical peak is proportional to the magnetic field by the splitting rate ν11. It is shown that ν11 changes linearly and parabolicly with the chiral angle and radius, respectively.

  19. Magnetic and Electrical Properties of Nitrogen-Doped Multiwall Carbon Nanotubes Fabricated by a Modified Chemical Vapor Deposition Method

    Directory of Open Access Journals (Sweden)

    María Luisa García-Betancourt

    2015-01-01

    Full Text Available Chemical vapor deposition (CVD is a preferential method to fabricate carbon nanotubes (CNTs. Several changes have been proposed to obtain improved CNTs. In this work we have fabricated nitrogen-doped multiwall carbon nanotubes (N-MWCNTs by means of a CVD which has been slightly modified. Such modification consists in changing the content of the by-product trap. Instead of acetone, we have half-filled the trap with an aqueous solution of NaCl (0–26.82 wt.%. Scanning electron microscope (SEM characterization showed morphological changes depending upon concentration of NaCl included in the trap. Using high resolution transmission electron microscopy several shape changes on the catalyst nanoparticles were also observed. According to Raman spectroscopy results N-MWCNTs fabricated using pure distillate water exhibit better crystallinity. Resistivity measurements performed on different samples by physical properties measurement Evercool system (PPMS showed metallic to semiconducting temperature dependent transitions when high content of NaCl is used. Results of magnetic properties show a ferromagnetic response to static magnetic fields and the coercive fields were very similar for all the studied cases. However, saturation magnetization is decreased if aqueous solution of NaCl is used in the trap.

  20. Properties of Cs-intercalated single wall carbon nanotubes investigated by 133Cs Nuclear Magnetic resonance

    KAUST Repository

    Schmid, Marc R.; Mahfouz, Remi; Bouhrara, Mohamed; Saih, Youssef; Mehring, Michael; Basset, Jean-Marie; Goze-Bac, Christophe; Abou-Hamad, Edy

    2012-01-01

    present within the carbon nanotube bundles. At high concentrations, the Cs (β)+ ions seem to occupy well defined positions relative to the carbon lattice. As a matter of fact, the Korringa relaxation behavior suggests a strong hyperfine coupling between Cs

  1. Realizing Technologies for Magnetized Target Fusion

    Energy Technology Data Exchange (ETDEWEB)

    Wurden, Glen A. [Los Alamos National Laboratory

    2012-08-24

    Researchers are making progress with a range of magneto-inertial fusion (MIF) concepts. All of these approaches use the addition of a magnetic field to a target plasma, and then compress the plasma to fusion conditions. The beauty of MIF is that driver power requirements are reduced, compared to classical inertial fusion approaches, and simultaneously the compression timescales can be longer, and required implosion velocities are slower. The presence of a sufficiently large Bfield expands the accessibility to ignition, even at lower values of the density-radius product, and can confine fusion alphas. A key constraint is that the lifetime of the MIF target plasma has to be matched to the timescale of the driver technology (whether liners, heavy ions, or lasers). To achieve sufficient burn-up fraction, scaling suggests that larger yields are more effective. To handle the larger yields (GJ level), thick liquid wall chambers are certainly desired (no plasma/neutron damage materials problem) and probably required. With larger yields, slower repetition rates ({approx}0.1-1 Hz) for this intrinsically pulsed approach to fusion are possible, which means that chamber clearing between pulses can be accomplished on timescales that are compatible with simple clearing techniques (flowing liquid droplet curtains). However, demonstration of the required reliable delivery of hundreds of MJ of energy, for millions of pulses per year, is an ongoing pulsed power technical challenge.

  2. Technology transfer considerations for the collider dipole magnet

    International Nuclear Information System (INIS)

    Goodzeit, C.; Fischer, R.

    1991-03-01

    The R ampersand D program at the national laboratories has resulted in significant advances in design and fabrication methods for the Collider Dipole Magnets. The status of the transfer of the technology developed by the laboratories is reviewed. The continuation of the technology transfer program is discussed with a description of: (1) the relation of technology transfer activities to collider dipole product development; (2) content of the program relating to key magnet performance issues; and (3) methods to implement the program. 5 refs

  3. Electrospinning direct synthesis of magnetic ZnFe{sub 2}O{sub 4}/ZnO multi-porous nanotubes with enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunlei [College of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023 (China); Tan, Xing [College of Biology and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023 (China); Yan, Juntao, E-mail: yanjuntaonihao@163.com [College of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023 (China); Chai, Bo [College of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023 (China); Li, Jianfen, E-mail: lijfen@163.com [College of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023 (China); Chen, Shizhong [College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430023 (China)

    2017-02-28

    Highlights: • ZnFe2O4/ZnO heterojunctions are firstly fabricated by electrospinning method. • ZnFe{sub 2}O{sub 4}/ZnO heterojunctions possess multi-porous nanotube structure. • ZnFe{sub 2}O{sub 4}/ZnO heterojunctions can significantly enhance photocatalytic activity. - Abstract: Magnetic ZnFe{sub 2}O{sub 4}/ZnO (ZFO/ZnO) multi-porous nanotubes have been first fabricated via a facile electrospinning and subsequent calcination process. A series of ZFO/ZnO photocatalysts with different ZFO molar content and morphologies are also obtained by varying the molar ratio of Zn/Fe metal salt and its dosage. The morphology, composition, crystal structure and specific surface area of achieved photocatalysts are systematically examined. TEM images demonstrate ZFO/ZnO-3 multi-porous nanotubes possess perfect 1D nanotube profile with hierarchical pores. HRTEM images confirm the formation of ZFO/ZnO heterojunctions. DRS spectra show that ZFO/ZnO-3 multi-porous nanotubes exhibit an enhanced absorption both in UV and visible-light region. PL spectra and photocurrent responses of ZFO/ZnO-3 multi-porous nanotube demonstrated that the photogenerated electrons and holes are effectively separated. Above all, ZFO/ZnO-3 multi-porous nanotubes photocatalysts with a larger specific surface area of 57.79 m{sup 2} g{sup −1} exhibit the best photocatalytic efficiency of 99% after 150 min under the solar irradiation for the decolorization of RhB. Moreover, ZFO/ZnO photocatalysts not only possess magnetic separation property, but also keep a relatively high photocatalytic efficiency even after four cycles, which is beneficial for practical application. In addition, both the formation and potential photocatalytic mechanisms of ZFO/ZnO-3 multi-porous nanotubes are proposed in detail.

  4. Structural, electronic and magnetic properties of Fe, Co, Ni monatomic nanochains encapsulated in armchair LiF nanotubes

    Directory of Open Access Journals (Sweden)

    Nia B. Arghavani

    2017-07-01

    Full Text Available Structural, electronic and magnetic properties of transition metal TM (TM = Fe, Co and Ni atomic chains wrapped in single walled LiF armchair nanotubes have been investigated by the first-principles calculations in the framework of the density functional theory. The generalized gradient approximation (GGA with Hubbard repulsion potential and without Hubbard repulsion was employed to describe the exchange-correlation potential. It is found that all these TM chains @LiFNTs systems have negative formation energy so they are stable and exothermic. Total density of states and partial densities of states analyses show that the spin polarization and the magnetic moment of TM chains @LiFNTs(n,n systems come mostly from the TM atom chains. All these nanocomposites are ferromagnetic (FM and spin splitting between spin up and down is observed. The high magnetic moment and spin polarization of the TM chains @LiFNT(n,n systems show that they can be used as magnetic nanostructures possessing potential current and future applications in permanent magnetism, magnetic recording, and spintronics.

  5. Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nanotubes and Their Use as Magnetically Recyclable Catalysts

    Directory of Open Access Journals (Sweden)

    Hongkun He

    2011-01-01

    Full Text Available We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nanotubes (CNTs. The superparamagnetic Fe3O4 nanoparticles with average size of 4∼5 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanopartilces and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanopaticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

  6. Overview of Planar Magnetic Technology — Fundamental Properties

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Andersen, Michael A. E.

    2014-01-01

    The momentum towards high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic components. This article gives an overview of planar magnetic technologies with respect to the development of modern power electronics. The major...... advantages and disadvantages in the use of planar magnetics for high frequency power converters are covered, and publications on planar magnetics are reviewed. A detailed survey of winding conduction loss, leakage inductance and winding capacitance for planar magnetics is presented so power electronics...

  7. Magnetic properties of zigzag (0,9 GaAs nanotube doped with 3d transition metals

    Directory of Open Access Journals (Sweden)

    R Fathi

    2016-06-01

    Full Text Available of 3d transition metals (Sc, Ti, Cr, Mn , Fe, Co, Ni in both far and close situations were studied based on spin polarised density functional theory using the generalized gradient approximation (LDA with SIESTA code. The electronic structures show that zigzag (0,9 GaAs nanotubes are non-magnetic semiconductors with direct band gap. It was revealed that doping of 11.11 % Fe and Mn concentrations substituted in Ga sites in ferromagnetic phase in far situation and Cr sites in ferromagnetic phase in near situation introduces half metallic behavior with %100 spin polarization. The unique structure of spin polarised energy levels is primarily attributed to strong hybridization of 3d transition metal and its nearest-neighbor As-4p orbitals. The results of this study can be useful for empirical studies on diluted magnetic semiconductors (DMSs and systemic investigation in 3d transitional metals. We suggest that GaAs nanotubes doped by transition metals would have a potential application as a spin polarised electron source for spintronic devices in the future.

  8. Nanomodified composite magnetic materials and their molding technologies

    Directory of Open Access Journals (Sweden)

    I. Timoshkov

    2018-05-01

    Full Text Available Advanced electro-magnetic machines and systems require new materials with improved properties. Heterogeneous 3D nanomodified soft magnetic materials could be efficiently applied. Multistage technology of iron particle surface nanomodification by sequential oxidation and Si-organic coatings will be reported. The thickness of layers is 0.5-5 nm. Compaction and annealing are the final steps of magnetic parts and components shaping. The soft magnetic composite material shows the features: resistivity is controlled by insulating coating thickness and equals up to ρ =10-4 Ω⋅m for metallic state and ρ =104 Ω⋅m for insulator state, maximum magnetic permeability is μm = 2500 and μm = 300 respectively, induction is up to Bm=2.1 T. These properties of composite soft magnetic material allow applying for transformers, throttles, stator-rotor of high-efficient and powerful electric machines in 10 kHz–1MGz frequency range. For microsystems and microcomponents application, good opportunity to improve their reliability is the use of nanocomposite materials. Electroplating technology of nanocomposite magnetic materials into the ultra-thick micromolds will be presented. Co-deposition of the soft magnetic alloys with inert hard nanoparticles allows obtaining materials with magnetic permeability up to μm=104, magnetic induction of Bs=(0.62–1.3 T. Such LIGA-like technology will be applied in MEMS to produce high reliable devices with advanced physical properties.

  9. Nanomodified composite magnetic materials and their molding technologies

    Science.gov (United States)

    Timoshkov, I.; Gao, Q.; Govor, G.; Sakova, A.; Timoshkov, V.; Vetcher, A.

    2018-05-01

    Advanced electro-magnetic machines and systems require new materials with improved properties. Heterogeneous 3D nanomodified soft magnetic materials could be efficiently applied. Multistage technology of iron particle surface nanomodification by sequential oxidation and Si-organic coatings will be reported. The thickness of layers is 0.5-5 nm. Compaction and annealing are the final steps of magnetic parts and components shaping. The soft magnetic composite material shows the features: resistivity is controlled by insulating coating thickness and equals up to ρ =10-4 Ωṡm for metallic state and ρ =104 Ωṡm for insulator state, maximum magnetic permeability is μm = 2500 and μm = 300 respectively, induction is up to Bm=2.1 T. These properties of composite soft magnetic material allow applying for transformers, throttles, stator-rotor of high-efficient and powerful electric machines in 10 kHz-1MGz frequency range. For microsystems and microcomponents application, good opportunity to improve their reliability is the use of nanocomposite materials. Electroplating technology of nanocomposite magnetic materials into the ultra-thick micromolds will be presented. Co-deposition of the soft magnetic alloys with inert hard nanoparticles allows obtaining materials with magnetic permeability up to μm=104, magnetic induction of Bs=(0.62-1.3) T. Such LIGA-like technology will be applied in MEMS to produce high reliable devices with advanced physical properties.

  10. Fast microextraction of phthalate acid esters from beverage, environmental water and perfume samples by magnetic multi-walled carbon nanotubes.

    Science.gov (United States)

    Luo, Yan-Bo; Yu, Qiong-Wei; Yuan, Bi-Feng; Feng, Yu-Qi

    2012-02-15

    In this work, magnetic carbon nanotubes (CNTs) were prepared by mixing the magnetic particles and multi-walled carbon nanotubes dispersed solutions. Due to their excellent adsorption capability towards hydrophobic compounds, the magnetic CNTs were used as adsorbent of magnetic solid-phase extraction (MSPE) to extract phthalate acid esters (PAEs), which are widely used in many consumable products with potential carcinogenic properties. By coupling MSPE with gas chromatography/mass spectrometry (GC/MS), a rapid, sensitive and cost-effective method for the analysis of PAEs was established. Our results showed that the limits of detection (LODs) of 16 PAEs ranged from 4.9 to 38 ng L(-1), which are much lower compared to the previously reported methods. And good linearities of the detection method were obtained with correlation coefficients (R(2)) between 0.9821 and 0.9993. In addition, a satisfying reproducibility was achieved by evaluating the intra- and inter-day precisions with relative standard deviations (RSDs) less than 11.7% and 14.6%, respectively. Finally, the established MSPE-GC/MS method was successfully applied to the determination of PAEs from bottled beverages, tap water and perfume samples. The recoveries of the 16 PAEs from the real samples ranged from 64.6% to 125.6% with the RSDs less than 16.5%. Taken together, the MSPE-GC/MS method developed in current study provides a new option for the detection of PAEs from real samples with complex matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Comparative kinetic study of functionalized carbon nanotubes and magnetic biochar for removal of Cd2+ ions from wastewater

    International Nuclear Information System (INIS)

    Ruthiraan, Manimaran; Thines, Raj Kogiladas; Abdullah, Ezzat Chan; Mubarak, Nabisab Mujawar; Jayakumar, Natesan Subramanian; Ganesan, Poobalan; Sahu, Jaya Narayan

    2015-01-01

    We did a comparative study between functionalized multiwall carbon nanotube (FMWCNTs), and magnetic biochar was carried out to determine the most efficient adsorbent to be employed in the Cd 2+ ion removal. We optimized parameters such as agitation speed, contact time, pH and adsorbent dosage using design expert vrsion 6.08. The statistical analysis reveals that optimized condition for highest removal of Cd 2+ are at pH 5.0, with dosage 1.0 g, agitation speed and contact time of 100 rpm and 90 minutes, respectively. For the initial concentration of 10mg/l, the removal efficiency of Cd 2+ using FMWCNTs was 90% and and 82% of magnetic biochar. The maximum Cd 2+ adsorption capacities of both FMWCNTs and magnetic biochar were calculated: 83.33mg/g and 62.5mg/g. The Langmuir and Freundlich constants for FMWCNTs were 0.056 L/mg and 13.613 L/mg, while 0.098 L/mg and 25.204 L/mg for magnetic biochar. The statistical analysis proved that FMWCNTs have better adsorption capacity compared to magnetic biochar and both models obeyed the pseudo-second-order

  12. Comparative kinetic study of functionalized carbon nanotubes and magnetic biochar for removal of Cd{sup 2+} ions from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Ruthiraan, Manimaran; Thines, Raj Kogiladas; Abdullah, Ezzat Chan [Universiti Teknologi Malaysia, Kuala Lumpur (Malaysia); Mubarak, Nabisab Mujawar [UCSI University, Kuala Lumpur (Malaysia); Jayakumar, Natesan Subramanian; Ganesan, Poobalan [University of Malaya, Kuala Lumpur (Malaysia); Sahu, Jaya Narayan [Institut Teknologi Brunei, Gadong (Brunei Darussalam)

    2015-03-15

    We did a comparative study between functionalized multiwall carbon nanotube (FMWCNTs), and magnetic biochar was carried out to determine the most efficient adsorbent to be employed in the Cd{sup 2+} ion removal. We optimized parameters such as agitation speed, contact time, pH and adsorbent dosage using design expert vrsion 6.08. The statistical analysis reveals that optimized condition for highest removal of Cd{sup 2+} are at pH 5.0, with dosage 1.0 g, agitation speed and contact time of 100 rpm and 90 minutes, respectively. For the initial concentration of 10mg/l, the removal efficiency of Cd{sup 2+} using FMWCNTs was 90% and and 82% of magnetic biochar. The maximum Cd{sup 2+} adsorption capacities of both FMWCNTs and magnetic biochar were calculated: 83.33mg/g and 62.5mg/g. The Langmuir and Freundlich constants for FMWCNTs were 0.056 L/mg and 13.613 L/mg, while 0.098 L/mg and 25.204 L/mg for magnetic biochar. The statistical analysis proved that FMWCNTs have better adsorption capacity compared to magnetic biochar and both models obeyed the pseudo-second-order.

  13. United States Superconducting MHD Magnet Technology Development Program

    International Nuclear Information System (INIS)

    Dawson, A.M.; Marston, P.G.; Thome, R.J.; Iwasa, Y.; Tarrh, J.M.

    1981-01-01

    A three-faceted program supported by the U.S. Dep of Energy is described. These facets include basic technology development, technology transfer and construction by industry of magnets for the national MHD program. The program includes the maintenance of a large component test facility; investigation of superconductor stability and structural behavior; measurements of materials' properties at low temperatures; structural design optimization; analytical code development; cryogenic systems and power supply design. The technology transfer program is designed to bring results of technology development and design and construction effort to the entire superconducting magnet community. The magnet procurement program is responsible for developing conceptual designs of magnets needed for the national MHD program, for issuing requests for quotation, selecting vendors and supervising design, construction, installation and test of these systems. 9 refs

  14. Technology spin-offs from the magnetic fusion energy program

    International Nuclear Information System (INIS)

    1982-05-01

    A description is given of 138 possible spin-offs from the magnetic fusion program. The spin-offs cover the following areas: (1) superconducting magnets, (2) materials technology, (3) vacuum systems, (4) high frequency and high power rf, (5) electronics, (6) plasma diagnostics, (7) computers, and (8) particle beams

  15. Fusion and technology: An introduction to the physics and technology of magnetic confinment fusion

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1984-01-01

    This book is an introduction covering all aspects of magnetic fusion and magnetic fusion technology. Physical property data relevant to fusion technology and a summary of fusion reactor design parameters are provided. Topics covered include: basic properties; equilibrium and transport confinement concepts; plasma heating; plasma wall interaction; magnetics; energy storage and transfer; interaction of radiation with matter; primary energy conversion and tritium breeding blanket; tritium and vacuum; and Fusion Reactor Design

  16. Compact and energy saving magnet technology for particle accelerators

    International Nuclear Information System (INIS)

    Baurichter, A.

    2013-01-01

    Despite the fact that funding agencies and industrial users of particle accelerators get more and more alerted about costs of civil engineering, installation and operation, only little effort has been put into development of sustainable, energy and cost saving accelerator technology. In order to reduce the total-cost-of ownership of accelerator magnets, operating at high electrical power for twenty years or more, permanent magnet based Green Magnet technology has been developed at a consortium around Danfysik's R and D team. Together with our partners from ISA, Aarhus University, the Aarhus School of Engineering, the company Sintex and Aalborg University all obstacles in applying permanent magnet technology as e.g. thermal drift and inhomogeneities of magnetic fields have been overcome. The first Green Magnet has now been operated for more than half a year in an Accelerator Mass Spectrometry facility at the ETH in Zurich. The performance of this B=0.43T 90 deg. H-type bending magnet and the most recently builtB=1T, 30 deg. C-type Green Magnet for the synchrotron light source ASTRID2 at ISA in Aarhus will be presented. Danfysik also is designing, manufacturing and testing 60 compact magnet systems, developed at MAX-Lab for the new MAXIV 3.0 GeV synchrotron light source. In addition, 12 for the 1.5 GeV light source and another 12 for the new SOLARIS light source in Krakow, Poland are buying built. Up to a dozen or more magnet functions have been integrated into one yoke of these compact magnet systems, which makes the new MAXIV light sources compact, energy saving and at the same time very bright. Test results and design concepts of the new MAXIV and SOLARIS magnets will be presented. (author)

  17. Halloysite nanotube-magnetic iron oxide nanoparticle hybrids for the rapid catalytic decomposition of pentachlorophenol

    NARCIS (Netherlands)

    Tsoufis, T.; Katsaros, F.; Kooi, B. J.; Bletsa, E.; Papageorgiou, S.; Deligiannakis, Y.; Panagiotopoulos, I.

    2017-01-01

    Halloysite clay are a very attractive class of alumino-silicate based, natural nanotubes possessing high aspect ratio, significant thermal and mechanical stability, as well as tunable surface chemistry. We report a novel, facile, synthetic approach involving a modified wet-impregnation method for

  18. Magnetic-Field Dependence of Tunnel Couplings in Carbon Nanotube Quantum Dots

    DEFF Research Database (Denmark)

    Grove-Rasmussen, Kasper; Grap, S.; Paaske, Jens

    2012-01-01

    By means of sequential and cotunneling spectroscopy, we study the tunnel couplings between metallic leads and individual levels in a carbon nanotube quantum dot. The levels are ordered in shells consisting of two doublets with strong- and weak-tunnel couplings, leading to gate-dependent level...

  19. Polymer nanotube nanocomposites: synthesis, properties, and applications

    National Research Council Canada - National Science Library

    Mittal, Vikas

    2010-01-01

    ... in these commercially important areas of polymer technology. It sums up recent advances in nanotube composite synthesis technology, provides basic introduction to polymer nanotubes nanocomposite technology for the readers new to this field, provides valuable...

  20. Electroless Co–P-Carbon Nanotube composite coating to enhance magnetic properties of grain-oriented electrical steel

    International Nuclear Information System (INIS)

    Goel, Vishu; Anderson, Philip; Hall, Jeremy; Robinson, Fiona; Bohm, Siva

    2016-01-01

    The effect of Co–P-CNT coating on the magnetic properties of grain oriented electrical steel was investigated. To analyse the coating, Raman spectroscopy, Superconducting QUantum Interference Device (SQUID), single strip testing, Scanning Electron Microscopy (SEM) and talysurf surface profilometry were performed. Raman spectra showed the D and G band which corroborates the presence of Multi-Walled Carbon Nanotubes (MWCNT) in the coating. The magnetic nature of the coating was confirmed by SQUID results. Power loss results show an improvement ranging 13–15% after coating with Co–P-CNT. The resistivity of the coating was measured to be 10 4 µΩ cm. Loss separation graphs were plotted before and after coating to study the improvement in power loss. It was found that the coating helps in reducing the hysteresis loss. The thickness of the coating was found to be 414±40 nm. The surface profilometry results showed that the surface roughness improved after coating the sample. - Highlights: • Co–P-CNT coating on Fe–3%Si steel was able to reduce the power loss by 13–15%. • Co–P-CNT coating reduced the surface roughness and enhanced the magnetic properties. • The decrease in coating thickness increased the stacking factor. • The stacking factor was further improved by the magnetic nature of the coating.

  1. Electroless Co–P-Carbon Nanotube composite coating to enhance magnetic properties of grain-oriented electrical steel

    Energy Technology Data Exchange (ETDEWEB)

    Goel, Vishu, E-mail: vishu.goel.nit@gmail.com [Wolfson Centre for Magnetics, Cardiff University, Cardiff CF243AA (United Kingdom); Anderson, Philip, E-mail: AndersonPI1@cf.ac.uk [Wolfson Centre for Magnetics, Cardiff University, Cardiff CF243AA (United Kingdom); Hall, Jeremy, E-mail: HallJP@cf.ac.uk [Wolfson Centre for Magnetics, Cardiff University, Cardiff CF243AA (United Kingdom); Robinson, Fiona, E-mail: fiona.cj.robinson@tatasteel.com [Cogent power Ltd., Newport NP19 0RB (United Kingdom); Bohm, Siva, E-mail: siva.bohm@tatasteel.com [IIT Bombay, Mumbai 400076 (India)

    2016-06-01

    The effect of Co–P-CNT coating on the magnetic properties of grain oriented electrical steel was investigated. To analyse the coating, Raman spectroscopy, Superconducting QUantum Interference Device (SQUID), single strip testing, Scanning Electron Microscopy (SEM) and talysurf surface profilometry were performed. Raman spectra showed the D and G band which corroborates the presence of Multi-Walled Carbon Nanotubes (MWCNT) in the coating. The magnetic nature of the coating was confirmed by SQUID results. Power loss results show an improvement ranging 13–15% after coating with Co–P-CNT. The resistivity of the coating was measured to be 10{sup 4} µΩ cm. Loss separation graphs were plotted before and after coating to study the improvement in power loss. It was found that the coating helps in reducing the hysteresis loss. The thickness of the coating was found to be 414±40 nm. The surface profilometry results showed that the surface roughness improved after coating the sample. - Highlights: • Co–P-CNT coating on Fe–3%Si steel was able to reduce the power loss by 13–15%. • Co–P-CNT coating reduced the surface roughness and enhanced the magnetic properties. • The decrease in coating thickness increased the stacking factor. • The stacking factor was further improved by the magnetic nature of the coating.

  2. MHD magnet technology development program summary, September 1982

    Energy Technology Data Exchange (ETDEWEB)

    1983-11-01

    The program of MHD magnet technology development conducted for the US Department of Energy by the Massachusetts Institute of Technology during the past five years is summarized. The general strategy is explained, the various parts of the program are described and the results are discussed. Subjects covered include component analysis, research and development aimed at improving the technology base, preparation of reference designs for commercial-scale magnets with associated design evaluations, manufacturability studies and cost estimations, the detail design and procurement of MHD test facility magnets involving transfer of technology to industry, investigations of accessory subsystem characteristics and magnet-flow-train interfacing considerations and the establishment of tentative recommendations for design standards, quality assurance procedures and safety procedures. A systematic approach (framework) developed to aid in the selection of the most suitable commercial-scale magnet designs is presented and the program status as of September 1982 is reported. Recommendations are made for future work needed to complete the design evaluation and selection process and to provide a sound technological base for the detail design and construction of commercial-scale MHD magnets. 85 references.

  3. MHD magnet technology development program summary, September 1982

    International Nuclear Information System (INIS)

    1983-11-01

    The program of MHD magnet technology development conducted for the US Department of Energy by the Massachusetts Institute of Technology during the past five years is summarized. The general strategy is explained, the various parts of the program are described and the results are discussed. Subjects covered include component analysis, research and development aimed at improving the technology base, preparation of reference designs for commercial-scale magnets with associated design evaluations, manufacturability studies and cost estimations, the detail design and procurement of MHD test facility magnets involving transfer of technology to industry, investigations of accessory subsystem characteristics and magnet-flow-train interfacing considerations and the establishment of tentative recommendations for design standards, quality assurance procedures and safety procedures. A systematic approach (framework) developed to aid in the selection of the most suitable commercial-scale magnet designs is presented and the program status as of September 1982 is reported. Recommendations are made for future work needed to complete the design evaluation and selection process and to provide a sound technological base for the detail design and construction of commercial-scale MHD magnets. 85 references

  4. Magnetization measurement of single La{sub 0.67}Ca{sub 0.33}MnO{sub 3} nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, D., E-mail: dario.antonio@cab.cnea.gov.a [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, (8400) S. C. de Bariloche (Argentina); Dolz, M.I.; Pastoriza, H. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, (8400) S. C. de Bariloche (Argentina)

    2010-03-15

    Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La{sub 0.67}Ca{sub 0.33}MnO{sub 3}. The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant k{sub M} of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H>>2K/M the magnetization is almost parallel to the applied magnetic field and for H<<2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition from one regime to the other, accompanied by a peak in the energy dissipation.

  5. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.

    2011-09-06

    We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

  6. Large magnetic coils for fusion technology

    International Nuclear Information System (INIS)

    Komarek, P.; Ulbricht, A.

    1989-01-01

    This paper reviews the current status of research in this field and outlines future tasks and experiments for the Next European Torus (NET). Research and development work accomplished so far permits generation and safe operation of magnetic fields up to 9 T by means of NbTi coils. Fields up to 11 T are feasible if the coils are cooled with superfluid helium at 1.8 K. The potential of the Nb 3 Sn coils promise achievement of magnetic fields between 12 and 13 T. (MM) [de

  7. Permanent magnet motor technology design and applications

    CERN Document Server

    Gieras, Jacek F

    2009-01-01

    Demonstrates the construction of permanent magnet (PM) motor drives and supplies ready-to-implement solutions to common roadblocks along the way. This book also supplies fundamental equations and calculations for determining and evaluating system performance, efficiency, reliability, and cost. It explores modern computer-aided design of PM motors.

  8. The heat storage material based on paraffin-modified multilayer carbon nanotubes with Nickel-zinc ferrite

    Science.gov (United States)

    Shchegolkov, A.; Shchegolkov, A.; Dyachkova, T.; Semenov, A.

    2018-02-01

    The paper presents an investigation of magnetically controlled heat-storage material based on paraffin, modified with multilayer carbon nanotubes with nickel-zinc ferrite. The technology of obtaining nanomodified material capable of interacting with magnetic field is presented. The study of the heat-exchange processes of charge/discharge with the help of magnetic field are carried out.

  9. Magnetic nanoparticles modified with polydimethylsiloxane and multi-walled carbon nanotubes for solid-phase extraction of fluoroquinolones

    International Nuclear Information System (INIS)

    Xu, S.; Jiang, C.; Lin, Y.; Jia, L.

    2012-01-01

    We have surface-functionalized magnetic particles (MPs) with polydimethylsiloxane and multi-walled carbon nanotubes in a two-step reaction. The MPs were applied to solid-phase extraction of the fluoroquinolones ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin prior to their determination by capillary liquid chromatography. The effects of sample pH, adsorption time, type of eluent, desorption time and desorption temperature were investigated. Under the optimum conditions, the extraction efficiencies are in the range from 81.5 % to 94.1 %, with relative standard deviations (RSDs) of -1 . The method was applied to the analysis of spiked mineral water and honey. The recoveries for the fluoroquinolones in the real samples range from 84.0 % to 112 %, with RSDs ranging from 2.9 % to 7.8 %. (author)

  10. AuPd Bimetallic Nanocrystals Embedded in Magnetic Halloysite Nanotubes: Facile Synthesis and Catalytic Reduction of Nitroaromatic Compounds

    Directory of Open Access Journals (Sweden)

    Lei Jia

    2017-10-01

    Full Text Available In this research, a facile and effective approach was developed for the preparation of well-designed AuPd alloyed catalysts supported on magnetic halloysite nanotubes (HNTs@Fe3O4@AuPd. The microstructure and the magnetic properties of HNTs@Fe3O4@AuPd were confirmed by transmission electron microscopy (TEM, high resolution TEM (HRTEM, energy-dispersive X-ray spectroscopy (EDS, and vibrating sample magnetometry (VSM analyses. The catalysts, fabricated by a cheap, environmentally friendly, and simple surfactant-free formation process, exhibited high activities during the reduction of 4-nitrophenol and various other nitroaromatic compounds. Moreover, the catalytic activities of the HNTs@Fe3O4@AuPd nanocatalysts were tunable via adjusting the atomic ratio of AuPd during the synthesis. As compared with the monometallic nanocatalysts (HNTs@Fe3O4@Au and HNTs@Fe3O4@Pd, the bimetallic alloyed HNTs@Fe3O4@AuPd nanocatalysts exhibited excellent catalytic activities toward the reduction of 4-nitrophenol (4-NP to 4-aminophenol. Furthermore, the as-obtained HNTs@Fe3O4@AuPd can be recycled several times, while retaining its functionality due to the stability and magnetic separation property.

  11. CLIQ. A new quench protection technology for superconducting magnets

    CERN Document Server

    Ravaioli, Emmanuele; ten Kate, H H J

    CLIQ, the Coupling-Loss Induced Quench system, is a new method for protecting superconducting magnets after a sudden transition to the normal state. It offers significant advantages over the conventional technology due to its effective mechanism for heating the superconductor relying on coupling loss and its robust electrical design, which makes it more reliable and less interfering with the coil winding process. The analysis of the electro-magnetic and thermal transients during and after a CLIQ discharge allows identifying the system parameters that affect the system performance and defining guidelines for implementing this technology on coils of various characteristics. Most existing superconducting magnets can be protected by CLIQ as convincingly shown by test results performed on magnets of different sizes, superconductor types, geometries, cables and strand parameters. Experimental results are successfully reproduced by means of a novel technique for modeling non-linear dynamic effects in superconducting...

  12. Fast magnetic field computation in fusion technology using GPU technology

    Energy Technology Data Exchange (ETDEWEB)

    Chiariello, Andrea Gaetano [Ass. EURATOM/ENEA/CREATE, Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, Via Roma 29, Aversa (CE) (Italy); Formisano, Alessandro, E-mail: Alessandro.Formisano@unina2.it [Ass. EURATOM/ENEA/CREATE, Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, Via Roma 29, Aversa (CE) (Italy); Martone, Raffaele [Ass. EURATOM/ENEA/CREATE, Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, Via Roma 29, Aversa (CE) (Italy)

    2013-10-15

    Highlights: ► The paper deals with high accuracy numerical simulations of high field magnets. ► The porting of existing codes of High Performance Computing architectures allowed to obtain a relevant speedup while not reducing computational accuracy. ► Some examples of applications, referred to ITER-like magnets, are reported. -- Abstract: One of the main issues in the simulation of Tokamaks functioning is the reliable and accurate computation of actual field maps in the plasma chamber. In this paper a tool able to accurately compute magnetic field maps produced by active coils of any 3D shape, wound with high number of conductors, is presented. Under linearity assumption, the coil winding is modeled by means of “sticks”, following each conductor's shape, and the contribution of each stick is computed using high speed Graphic Computing Units (GPU's). Relevant speed enhancements with respect to standard parallel computing environment are achieved in this way.

  13. Use of permanent magnets in accelerator technology: Present and future

    International Nuclear Information System (INIS)

    Halbach, K.

    1987-01-01

    Permanent magnet systems have some generic properties that, under some circumstances, make them not only mildy preferable over electromagnets, but make it possible to do things that can not be done with any other technology. After a general discussion of these generic advantages, some specific permanent magnet systems will be described. Special emphasis will be placed on systems that have now, or are likely to have in the future, a significant impact on how some materials research is conducted

  14. Recent advances in the technology of superconducting accelerator magnets

    International Nuclear Information System (INIS)

    Taylor, C.E.

    1985-05-01

    Recent progress in technology of high-current-density cables for SSC model magnets is summarized. NbTi cable with J/sub c/ up to 50% higher than Tevatron cable can be expected. Magnetization effects can be predicted and corrected with several new techniques. Development of Superconductor with 2 to 3 μm filament diameter and high J/sub c/ is expected. 15 refs., 3 figs

  15. Nanotube cathodes.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-11-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  16. Nanotube cathodes

    International Nuclear Information System (INIS)

    Overmyer, Donald L.; Lockner, Thomas Ramsbeck; Siegal, Michael P.; Miller, Paul Albert

    2006-01-01

    Carbon nanotubes have shown promise for applications in many diverse areas of technology. In this report we describe our efforts to develop high-current cathodes from a variety of nanotubes deposited under a variety of conditions. Our goal was to develop a one-inch-diameter cathode capable of emitting 10 amperes of electron current for one second with an applied potential of 50 kV. This combination of current and pulse duration significantly exceeds previously reported nanotube-cathode performance. This project was planned for two years duration. In the first year, we tested the electron-emission characteristics of nanotube arrays fabricated under a variety of conditions. In the second year, we planned to select the best processing conditions, to fabricate larger cathode samples, and to test them on a high-power relativistic electron beam generator. In the first year, much effort was made to control nanotube arrays in terms of nanotube diameter and average spacing apart. When the project began, we believed that nanotubes approximately 10 nm in diameter would yield sufficient electron emission properties, based on the work of others in the field. Therefore, much of our focus was placed on measured field emission from such nanotubes grown on a variety of metallized surfaces and with varying average spacing between individual nanotubes. We easily reproduced the field emission properties typically measured by others from multi-wall carbon nanotube arrays. Interestingly, we did this without having the helpful vertical alignment to enhance emission; our nanotubes were randomly oriented. The good emission was most likely possible due to the improved crystallinity, and therefore, electrical conductivity, of our nanotubes compared to those in the literature. However, toward the end of the project, we learned that while these 10-nm-diameter CNTs had superior crystalline structure to the work of others studying field emission from multi-wall CNT arrays, these nanotubes still

  17. Use of permanent magnets in accelerator technology: Present and future

    International Nuclear Information System (INIS)

    Halbach, K.

    1987-05-01

    This report is a collection of viewgraphs discussing accelerator magnets. Permanent magnet systems have some generic properties that, under some circumstances, make them not only mildly preferable over electromagnets, but make it possible to do things that can not be done with any other technology. After a general discussion of these generic advantages, some specific permanent magnet systems will be described. Special emphasis will be placed on systems that have now, or are likely to have in the future, a significant impact on how some materials research is conducted. 4 refs., 33 figs

  18. One pot synthesis of magnetic graphene/carbon nanotube composites as magnetic dispersive solid-phase extraction adsorbent for rapid determination of oxytetracycline in sewage water.

    Science.gov (United States)

    Sun, Yunyun; Tian, Jing; Wang, Lu; Yan, Hongyuan; Qiao, Fengxia; Qiao, Xiaoqiang

    2015-11-27

    A simple and time-saving one pot synthesis of magnetic graphene/carbon nanotube composites (M-G/CNTs) was developed that could avoid the tedious drying process of graphite oxide, and G/CNTs were modified by Fe3O4 nanoparticles in the reduction procedure. It contributed to a shorten duration of the synthesis process of M-G/CNTs. The obtained M-G/CNTs were characterized and the results indicated that CNTs and Fe3O4 nanoparticles were served as spacer distributing to the layers of graphene, which was beneficial for enlarging surface area and improving extraction efficiency. Moreover, M-G/CNTs showed good magnetic property and outstanding thermal stability. Then M-G/CNTs were applied as adsorbent of magnetic dispersive solid-phase extraction for rapid extraction and determination of oxytetracycline in sewage water. Under the optimum conditions, good linearity was obtained in the range of 20-800ngmL(-1) and the recoveries were ranged from 95.5% to 112.5% with relative standard deviations less than 5.8%. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Sub-Audio Magnetics: Miniature Sensor Technology for Simultaneous Magnetic and Electromagnetic Detection of UXO

    Science.gov (United States)

    2010-07-01

    inputs such as laser altimeters and fluxgate magnetometers to determine heading errors etc. 2.2 Technology Development Introduction The technology...hardware and software development, testing and performance evaluation. Initial funding saw the development of a fast sampling magnetometer (called the...Electromagnetic Induction TMI Total Magnetic Intensity TM-6 Magnetometer system developed for SAM applications Tx Transmitter UXO Unexploded

  20. Self-assembly synthesis of hollow double silica @ mesoporous magnesium silicate magnetic hierarchical nanotubes with excellent performance for fast removal of cationic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Yaxi; Cui, Guijia; Liu, Yan; Li, Haizhen; Sun, Zebin; Yan, Shiqiang, E-mail: yansq@lzu.edu.cn

    2016-11-30

    Highlights: • Hollow double silica @ mesoporous magnesium silicate magnetic hierarchical nanotubes were synthesized for the first time. • MgSNTs showed excellent prformance for the removal of low concentration methylene blue and high concentration rodamine B. • It could be easily discovered from solution. - Abstract: In this work, novel hollow double silica @ mesoporous magnesium silicate magnetic hierarchical nanotubes (MgSNTs) were successfully synthesized by using magnetic mesoporous silica nanocapsules (MSNCs) as morphology templates via a hydrothermal method for the first time. MgSNTs were characterized by transmission electron microscopy, Mapping, X-ray diffraction, Fourier transform infraed spetroscopy, N{sub 2} adorption-desorption, X-ray photoelectron spectroscopy and vibrating sample magnetometry. The synthesized MgSNTs with high specific surface area (588 m{sup 2}/g), average pore width (7.13 nm) and pore volume (1.05 cm{sup 3}/g) had high removal efficiency for low concentration methylene blue (70 mg/L, 299 mg/g) and high adsorption capacities for high concentration rodamine B (300 mg/L, 752 mg/g). Besides, it could be easily recovered due with the help of γ-Fe{sub 2}O{sub 3} in the inner chamber. Moreover, the adsorption capacity, the influence of pH, adsorption kinetics and adsorption mechanism were also carefully and comprehensively investigated. The results indicated that magnetic magnesium silicate nanotubes (MgSNTs) using mesoporous silica nanocapsules as the assisted templates were promsing adsorbents for water purification.

  1. Health technology assessment of magnet therapy for relieving pain.

    Science.gov (United States)

    Arabloo, Jalal; Hamouzadeh, Pejman; Eftekharizadeh, Fereshteh; Mobinizadeh, Mohammadreza; Olyaeemanesh, Alireza; Nejati, Mina; Doaee, Shila

    2017-01-01

    Background: Magnet therapy has been used increasingly as a new method to alleviate pain. Magnetic products are marketed with claims of effectiveness for reducing pain of various origins. However, there are inconsistent results from a limited number of randomized controlled trials (RCTs) testing the analgesic efficacy of magnet therapy. This study aimed to evaluate the safety and effectiveness of magnet therapy on reliving various types of pain. Methods: A systematic search of two main medical databases (Cochrane Library and Ovid Medline) was conducted from 1946 to May 2014. Only English systematic reviews that compared magnet therapy with other conventional treatments in patients with local pain in terms of pain relieving measures were included. The results of the included studies were thematically synthesized. Results: Eight studies were included. Magnet therapy could be used to alleviate pain of various origins including pain in various organs, arthritis, myofascial muscle pain, lower limb muscle cramps, carpal tunnel syndrome and pelvic pain. Results showed that the effectiveness of magnetic therapy was only approved in muscle pains, but its effectiveness in other indications and its application as a complementary treatment have not been established. Conclusion: According to the results, it seems that magnet therapy could not be an effective treatment for relieving different types of pain. Our results highlighted the need for further investigations to be done in order to support any recommendations about this technology.

  2. Polyaniline-stabilized electromagnetic wave absorption composites of reduced graphene oxide on magnetic carbon nanotube film

    Science.gov (United States)

    Li, Jinsong; Duan, Yan; Lu, Weibang; Chou, Tsu-Wei

    2018-04-01

    A multi-layered composite with exceptionally high electromagnetic wave-absorbing capacity and performance stability was fabricated via the facile electrophoresis of a reduced graphene oxide network on carbon nanotube (CNT)-Fe3O4-polyaniline (PANI) film. Minimum reflection loss (RL) of -53.2 dB and absorbing bandwidth of 5.87 GHz (graphene-based absorbers. In particular, comparing to the original composites, the minimum RL and bandwidth (< -10 dB) maintains 82.5% and 99.7%, respectively, after 20 h charge/discharge cycling, demonstrating high environmental suitability.

  3. Novel technologies and configurations of superconducting magnets for MRI

    International Nuclear Information System (INIS)

    Lvovsky, Yuri; Stautner, Ernst Wolfgang; Zhang Tao

    2013-01-01

    A review of non-traditional approaches and emerging trends in superconducting magnets for MRI is presented. Novel technologies and concepts have arisen in response to new clinical imaging needs, changes in market cost structure, and the realities of newly developing markets. Among key trends are an increasing emphasis on patient comfort and the need for ‘greener’ magnets with reduced helium usage. The paper starts with a brief overview of the well-optimized conventional MR magnet technology that presently firmly occupies the dominant position in the imaging market up to 9.4 T. Non-traditional magnet geometries, with an emphasis on openness, are reviewed. The prospects of MgB 2 and high-temperature superconductors for MRI applications are discussed. In many cases the introduction of novel technologies into a cost-conscious commercial market will be stimulated by growing needs for advanced customized procedures, and specialty scanners such as orthopedic or head imagers can lead the way due to the intrinsic advantages in their design. A review of ultrahigh-field MR is presented, including the largest 11.7 T Iseult magnet. Advanced cryogenics approaches with an emphasis on low-volume helium systems, including hermetically sealed self-contained cryostats requiring no user intervention, as well as future non-traditional non-helium cryogenics, are presented. (topical review)

  4. Donor impurity in nanotube with two GaAs/GaAlAs quantum wells: Magnetic field effects

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, J D; Escorcia, R; Sierra-Ortega, J, E-mail: jdavid0831@gmail.co [Grupo de Investigacion en teorIa de la Materia Condensada, Universidad del Magdalena, A.A. 731, Santa Marta (Colombia)

    2009-05-01

    Micro-tubes containing two GaAs/GaAlAs quantum wells (QWs) in a section of the tube layer has been fabricated and optical properties of the embedded QWs has been studied. The ground state binding energy of an off-axis donor in a cylindrical nanotube, containing two GaAs/GaAlAs quantum wells (QWs) in the presence of a uniform magnetic field is calculated as a function of the donor location as well as the density of states. A trial function for describing the asymmetric electron charge distribution is taken as a product of the combination of 1s and 2p{sub x,y} subband wave functions and an unknown function that depends only on electron-ion separation. We found that the increasing the magnetic field the increasing the binding energy while the impurity is located in the QW1, whereas the opposite occurs when the impurity is located in the QW2. Two peaks in the curves of the binding energy, as a function of the impurity position, are also found as well as in the density of impurity states.

  5. Preliminary analysis of patent trends for magnetic fusion technology

    International Nuclear Information System (INIS)

    Levine, L.O.; Ashton, W.B.; Campbell, R.S.

    1984-02-01

    This study presents a preliminary analysis of development trends in magnetic fusion technology based on data from US patents. The research is limited to identification and description of general patent activity and ownership characteristics for 373 patents. The results suggest that more detailed studies of fusion patents could provide useful R and D planning information

  6. CLIQ. A new quench protection technology for superconducting magnets

    NARCIS (Netherlands)

    Ravaioli, Emanuele

    2015-01-01

    CLIQ, the Coupling-Loss Induced Quench system, is a new method for protecting superconducting magnets after a sudden transition to the normal state. It offers significant advantages over the conventional technology due to its effective mechanism for heating the superconductor relying on coupling

  7. Magnetic Refrigeration – an Energy Efficient Technology for the Future

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Smith, Anders; Pryds, Nini

    2009-01-01

    . This magnetocaloric effect is inherent to all magnetic materials, but manifests itself stronger in some materials. The thermodynamically reversible nature of the magnetocaloric effect holds out the promise of a more energy efficient method of refrigeration compared to conventional compressor technology. Coupling...

  8. Properties of K,Rb-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Mahfouz, R. [Division of Physical Sciences & Engineering, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia); Bouhrara, M. [Department of Chemistry, School of Science and Technology, Nazarbayev University, 010000 Astana, Republic of Kazakhstan (Kazakhstan); Kim, Y. [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Wågberg, T. [Department of Physics, Umeå University, 901 87 Umeå (Sweden); Goze-Bac, C. [nanoNMRI Group, UMR5587, Université Montpellier II, Place E. Bataillon, 34095 Montpellier, Cedex 5 (France); Abou-Hamad, E., E-mail: edy.abouhamad@kaust.edu.sa [KAUST Catalysis Center (KCC) King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2015-09-21

    We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods can be derived from {sup 13}C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T{sub 1}) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C{sub 60} that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C{sub 60} at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(E{sub F})

  9. Synthesis of polydopamine-functionalized magnetic graphene and carbon nanotubes hybrid nanocomposites as an adsorbent for the fast determination of 16 priority polycyclic aromatic hydrocarbons in aqueous samples.

    Science.gov (United States)

    Chen, Kun; Jin, Rongrong; Luo, Chen; Song, Guoxin; Hu, Yaoming; Cheng, Hefa

    2018-04-01

    A novel adsorbent made of polydopamine-functionalized magnetic graphene and carbon nanotubes hybrid nanocomposite was synthesized and applied to determine 16 priority polycyclic aromatic hydrocarbons by magnetic solid phase extraction in water samples. FTIR spectroscopy, transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy consistently indicate that the synthesized adsorbents are made of core-shell nanoparticles well dispersed on the surface of graphene and carbon nanotubes. The major factors affecting the extraction efficiency, including the pH value of samples, the amount of adsorbent, adsorption time and desorption time, type and volume of desorption solvent, were systematically optimized. Under the optimum extraction conditions, a linear response was obtained for polycyclic aromatic hydrocarbons between concentrations of 10 and 500 ng/L with the correlation coefficients ranging from 0.9958 to 0.9989, and the limits of detection (S/N = 3) were between 0.1 and 3.0 ng/L. Satisfactory results were also obtained when applying these magnetic graphene/carbon nanotubes/polydopamine hybrid nanocomposites to detect polycyclic aromatic hydrocarbons in several environmental aqueous samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. γ-Fe{sub 2}O{sub 3} magnetic nanoparticle functionalized with carboxylated multi walled carbon nanotube: Synthesis, characterization, analytical and biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Kılınç, Ersin, E-mail: kilincersin@gmail.com

    2016-03-01

    In recent years, magnetic nanoparticles attained special interest in nanobiotechnology and nanomedicine due to their uniqe properties and biocompatibilities. From this perspective, hybride nanostructure composed from γ-Fe{sub 2}O{sub 3} magnetic nanoparticle and carboxylated multi walled carbon nanotube was synthesized and characterized by FT-IR, VSM, SEM, HR-TEM and ICP-OES. Microscopy images showed that magnetic nanoparticles were nearly spherical structure that arranged on the axis of carboxylated MWCNT. Particle size was found lower than 10 nm. VSM results showed that the obtained magnetic nanoparticles presented superparamagnetic properties at room temperature. The magnetic saturation value was determined as 35.2 emu/g. It was used for the adsorption and controlled release of harmane, a potent tremor-producing neurotoxin. Maximum adsorption capacity was calculated as 151.5 mg/g from Langmuir isotherm. Concentration of harmane was determined by HPLC with fluorescence detection. The antimicrobial activity of synthesized magnetic nanoparticle was investigated against gram-negative and gram-positive bacteria. However, no activity was observed. - Highlights: • A nanomaterial from gamma iron oxide and multi walled carbon nanotube was synthesized. • It was characterized and microstructure was investigated. • No antimicrobial activity was observed. • Adsorption and release of harmane on its were examined.

  11. γ-Fe_2O_3 magnetic nanoparticle functionalized with carboxylated multi walled carbon nanotube: Synthesis, characterization, analytical and biomedical application

    International Nuclear Information System (INIS)

    Kılınç, Ersin

    2016-01-01

    In recent years, magnetic nanoparticles attained special interest in nanobiotechnology and nanomedicine due to their uniqe properties and biocompatibilities. From this perspective, hybride nanostructure composed from γ-Fe_2O_3 magnetic nanoparticle and carboxylated multi walled carbon nanotube was synthesized and characterized by FT-IR, VSM, SEM, HR-TEM and ICP-OES. Microscopy images showed that magnetic nanoparticles were nearly spherical structure that arranged on the axis of carboxylated MWCNT. Particle size was found lower than 10 nm. VSM results showed that the obtained magnetic nanoparticles presented superparamagnetic properties at room temperature. The magnetic saturation value was determined as 35.2 emu/g. It was used for the adsorption and controlled release of harmane, a potent tremor-producing neurotoxin. Maximum adsorption capacity was calculated as 151.5 mg/g from Langmuir isotherm. Concentration of harmane was determined by HPLC with fluorescence detection. The antimicrobial activity of synthesized magnetic nanoparticle was investigated against gram-negative and gram-positive bacteria. However, no activity was observed. - Highlights: • A nanomaterial from gamma iron oxide and multi walled carbon nanotube was synthesized. • It was characterized and microstructure was investigated. • No antimicrobial activity was observed. • Adsorption and release of harmane on its were examined.

  12. The magnetic diagnostics subsystem of the LISA Technology Package

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Aguilo, M; Garcia-Berro, E [Departament de Fisica Aplicada, Universitat Politecnica de Catalunya, c/Esteve Terrades, 5, 08860 Castelldefels (Spain); Lobo, A; Mateos, N; Sanjuan, J, E-mail: marc.diaz.aguilo@fa.upc.ed [Institut d' Estudis Espacials de Catalunya, c/Gran Capita 2-4, Edif. Nexus 104, 08034 Barcelona (Spain)

    2010-05-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  13. The magnetic diagnostics subsystem of the LISA Technology Package

    International Nuclear Information System (INIS)

    Diaz-Aguilo, M; Garcia-Berro, E; Lobo, A; Mateos, N; Sanjuan, J

    2010-01-01

    The Magnetic Diagnostics Subsystem of the LISA Technology Package (LTP) on board the LISA Pathfinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at the positions they occupy. However, their readouts do not provide a direct measurement of the magnetic field at the positions of the test masses. Therefore, an interpolation method must be implemented to obtain this information. However, such interpolation process faces serious difficulties. Indeed, the size of the interpolation region is excessive for a linear interpolation to be reliable, and the number of magnetometer channels does not provide sufficient data to go beyond that poor approximation. Recent research points to a possible alternative to address the magnetic interpolation problem by means of neural network algorithms. The key point of this approach is the ability neural networks have to learn from suitable training data representing the magnetic field behaviour. Despite the large distance to the test masses and the insufficient magnetic readings, artificial neural networks are able to significantly reduce the estimation error to acceptable levels. The learning efficiency can be best improved by making use of data obtained from on-ground measurements prior to mission launch in all relevant satellite locations and under real operation conditions. Reliable information on that appears to be essential for a meaningful assessment of magnetic noise in the LTP.

  14. Isotactic polypropylene/carbon nanotube composites prepared by latex technology: Electrical conductivity study

    NARCIS (Netherlands)

    Grossiord, N.; Wouters, M.E.L.; Miltner, H.E.; Lu, K.; Loos, J.; Van Mele, B.; Koning, C.E.

    2010-01-01

    Several series of nanocomposites were prepared using a latex-based process, the main step of which consisted of mixing an aqueous suspension of exfoliated carbon nanotubes (CNTs) and a polymer latex. In the present work, a systematic study on the electrical properties of fully amorphous (polystyrene

  15. Novel Antimicrobial Titanium Dioxide Nanotubes Obtained through a Combination of Atomic Layer Deposition and Electrospinning Technologies

    Science.gov (United States)

    Patiño, Cristian; Galotto, María Jose; Palma, Juan Luis; Alburquenque, Daniela

    2018-01-01

    The search for new antimicrobial substances has increased in recent years. Antimicrobial nanostructures are one of the most promising alternatives. In this work, titanium dioxide nanotubes were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers (PVN) at different temperatures with the purpose of obtaining antimicrobial nanostructures with a high specific area. Electrospinning and ALD parameters were studied in order to obtain PVN with smallest diameter and highest deposition rate, respectively. Chamber temperature was a key factor during ALD process and an appropriate titanium dioxide deposition performance was achieved at 200 °C. Subsequently, thermal and morphological analysis by SEM and TEM microscopies revealed hollow nanotubes were obtained after calcination process at 600 °C. This temperature allowed complete polymer removal and influenced the resulting anatase crystallographic structure of titanium dioxide that positively affected their antimicrobial activities. X-ray analysis confirmed the change of titanium dioxide crystallographic structure from amorphous phase of deposited PVN to anatase crystalline structure of nanotubes. These new nanostructures with very large surface areas resulted in interesting antimicrobial properties against Gram-positive and Gram-negative bacteria. Titanium dioxide nanotubes presented the highest activity against Escherichia coli with 5 log cycles reduction at 200 μg/mL concentration. PMID:29495318

  16. Synthesis and characterization of CoFe{sub 2}O{sub 4} magnetic nanotubes, nanorods and nanowires. Formation of magnetic structured elastomers by magnetic field-induced alignment of CoFe{sub 2}O{sub 4} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Antonel, P. Soledad [Universidad de Buenos Aires, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Instituto de Química Física de Materiales, Ambiente y Energía (INQUIMAE) (Argentina); Oliveira, Cristiano L. P. [Universidade de São Paulo, Grupo de Fluidos Complexos, Instituto de Física (Brazil); Jorge, Guillermo A. [Universidad Nacional de General Sarmiento, Instituto de Ciencias (Argentina); Perez, Oscar E. [Universidad de Buenos Aires, Departamento de Industrias, Facultad de Ciencias Exactas y Naturales (Argentina); Leyva, A. Gabriela, E-mail: leyva@tandar.cnea.gov.ar [Universidad Nacional de San Martín, Grupo de Materia Condensada, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica (Argentina); Escuela de Ciencia y Tecnología (Argentina); Negri, R. Martín, E-mail: rmn@qi.fcen.uba.ar [Universidad de Buenos Aires, Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Instituto de Química Física de Materiales, Ambiente y Energía (INQUIMAE) (Argentina)

    2015-07-15

    Magnetic CoFe{sub 2}O{sub 4} nanotubes, nanorods and nanowires were synthesized by the template method. The materials are highly crystalline and formed by compactly packed ceramic particles whose equivalent size diameter depends on the nanostructure type. Nanotubes and nanorods present the remarkable characteristic of having very large coercive fields (1000–1100 Oe) in comparison with nanoparticles of the same crystallite size (400 Oe) while keeping similar saturation magnetization (53–55 emu/g). Nanorods were used as filler material in polydimethylsiloxane elastomer composites, which were structured by curing in the presence of uniform magnetic field, H{sub curing}. In that way the nanorods agglomerate in the cured elastomer, forming needles-like structures (pseudo-chains) oriented in the direction of H{sub curing}. SEM analysis show that pseudo-chains are formed by bunches of nanorods oriented in that direction. At the considered filler concentration (1 % w/w), the structured elastomers conserve the magnetic properties of the fillers, that is, high coercive fields without observing magnetic anisotropy. The elastomer composites present strong elastic anisotropy, with compression constants about ten times larger in the direction parallel to the pseudo-chains than in the perpendicular direction, as determined by compression stress–strain curves. That anisotropic factor is about three-four times higher than that observed when using spherical CoFe{sub 2}O{sub 4} nanoparticles or elongated Ni nanochains. Hence, the use of morphological anisotropic structures (nanorods) results in composites with enhanced elastic anisotropy. It is also remarkable that the large elastic anisotropy was obtained at lower filler concentration compared with the above-mentioned systems (1 % w/w vs. 5–10 % w/w)

  17. Synthesis and characterization of CoFe2O4 magnetic nanotubes, nanorods and nanowires. Formation of magnetic structured elastomers by magnetic field-induced alignment of CoFe2O4 nanorods

    International Nuclear Information System (INIS)

    Antonel, P. Soledad; Oliveira, Cristiano L. P.; Jorge, Guillermo A.; Perez, Oscar E.; Leyva, A. Gabriela; Negri, R. Martín

    2015-01-01

    Magnetic CoFe 2 O 4 nanotubes, nanorods and nanowires were synthesized by the template method. The materials are highly crystalline and formed by compactly packed ceramic particles whose equivalent size diameter depends on the nanostructure type. Nanotubes and nanorods present the remarkable characteristic of having very large coercive fields (1000–1100 Oe) in comparison with nanoparticles of the same crystallite size (400 Oe) while keeping similar saturation magnetization (53–55 emu/g). Nanorods were used as filler material in polydimethylsiloxane elastomer composites, which were structured by curing in the presence of uniform magnetic field, H curing . In that way the nanorods agglomerate in the cured elastomer, forming needles-like structures (pseudo-chains) oriented in the direction of H curing . SEM analysis show that pseudo-chains are formed by bunches of nanorods oriented in that direction. At the considered filler concentration (1 % w/w), the structured elastomers conserve the magnetic properties of the fillers, that is, high coercive fields without observing magnetic anisotropy. The elastomer composites present strong elastic anisotropy, with compression constants about ten times larger in the direction parallel to the pseudo-chains than in the perpendicular direction, as determined by compression stress–strain curves. That anisotropic factor is about three-four times higher than that observed when using spherical CoFe 2 O 4 nanoparticles or elongated Ni nanochains. Hence, the use of morphological anisotropic structures (nanorods) results in composites with enhanced elastic anisotropy. It is also remarkable that the large elastic anisotropy was obtained at lower filler concentration compared with the above-mentioned systems (1 % w/w vs. 5–10 % w/w)

  18. Low temperature synthesis of coiled carbon nanotubes and their magnetic properties

    Science.gov (United States)

    Krishna, Vemula Mohana; Somanathan, T.; Manikandan, E.

    2018-04-01

    In this paper, coiled like structure of carbon nanotubes (c-CNTs) have been effectively grown on bi-metal substituted α-alumina nanoparticles catalyst by chemical vapor deposition (CVD) system. Highly graphitized and dense bundles of carbon product were attained at a low temperature of 550 °C. The coiled carbon nanostructures in very longer lengths were noticed by field emission scanning electron microscope (FESEM) observation. Furthermore, high purity material was achieved, which correlates the energy dispersive x-ray spectroscopy (EDX) analysis. High resolution transmission electron microscope (HRTEM) revealed the diameter and graphitization of coiled structures. The superparamagnetic like behavior was observed at room temperature for the as-synthesized product, which was found by VSM investigation.

  19. Resonant Magnetic Field Sensors Based On MEMS Technology

    Directory of Open Access Journals (Sweden)

    Elías Manjarrez

    2009-09-01

    Full Text Available Microelectromechanical systems (MEMS technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration.

  20. Resonant Magnetic Field Sensors Based On MEMS Technology

    Science.gov (United States)

    Herrera-May, Agustín L.; Aguilera-Cortés, Luz A.; García-Ramírez, Pedro J.; Manjarrez, Elías

    2009-01-01

    Microelectromechanical systems (MEMS) technology allows the integration of magnetic field sensors with electronic components, which presents important advantages such as small size, light weight, minimum power consumption, low cost, better sensitivity and high resolution. We present a discussion and review of resonant magnetic field sensors based on MEMS technology. In practice, these sensors exploit the Lorentz force in order to detect external magnetic fields through the displacement of resonant structures, which are measured with optical, capacitive, and piezoresistive sensing techniques. From these, the optical sensing presents immunity to electromagnetic interference (EMI) and reduces the read-out electronic complexity. Moreover, piezoresistive sensing requires an easy fabrication process as well as a standard packaging. A description of the operation mechanisms, advantages and drawbacks of each sensor is considered. MEMS magnetic field sensors are a potential alternative for numerous applications, including the automotive industry, military, medical, telecommunications, oceanographic, spatial, and environment science. In addition, future markets will need the development of several sensors on a single chip for measuring different parameters such as the magnetic field, pressure, temperature and acceleration. PMID:22408480

  1. Evaluation of environmental control technologies for magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-01

    The peripheral magnetic fields of several energy-related technologies are calculated, and shielding options are studied for three field intensities as possible exposure levels: 200 G, 10 G, and 0.3 G. Seven fusion reactor designs are studied. For a 200-G field level, shielding is not required. For the 10- and 0.3-G levels, land is the most economical shielding method, with shield coils an acceptable alternative at 0.3 G. Nonnuclear technologies studied are superconducting magnetic energy storage, magnetohydrodynamic (MHD) electric generators, magnetically levitated vehicles, superconducting ac generators, and underground transmission lines. Superconducting ac generators and underground transmission lines require no shielding. The superconducting magnetic energy storage coil requires no shielding for 200 G. Both a shield coil and land are needed to meet 10 G or 0.3 G. The MHD generator needs no shielding to 200 G and 10 G. Land is the most economical means of meeting the 0.3 G level. Most of the magnetically levitated vehicles require no shielding to 200 G. The field on-board can be reduced from 200 to 25 G, depending upon the vehicle design, with shield coils. The use of iron, or another permeable material, is necessary to reduce the field to 10 G or 0.3 G. However, iron introduces too much added weight to allow efficient operation.

  2. Development of magnetic molecularly imprinted polymers based on carbon nanotubes - application for trace analysis of pyrethroids in fruit matrices.

    Science.gov (United States)

    Ma, Guifu; Chen, Ligang

    2014-02-14

    The sensitive and efficient magnetic molecularly imprinted polymers (MMIPs) were successfully synthesized using carbon nanotubes as matrix and Fe3O4 particles as magnetic ingredient. Tetraethyl orthosilicate was used as modification material of the carbon nanotubes. Cyhalothrin, methacrylic acid and ethylene glycol dimethacrylate were used as template molecule, functional monomer and cross-linker, respectively. Azo-isobutyronitrile and polyvinylpyrrolidone were used as initiator and dispersant, respectively. The MMIPs were used for the separation of pyrethroids including beta-cyfluthrin, cyhalothrin, cyphenothrin and permethrin in fruit samples followed by high performance liquid chromatography analysis. The polymers were characterized with Fourier transform infrared spectrometry, Brunauer-Emmett-Teller method, transmission electron microscopy and a physical property measurement system. The isothermal absorption experiment, kinetics absorption experiment and selectivity of MMIPs were studied in detail. Scatchard analysis revealed that two kinds of different binding sites existed in MMIPs. The maximum adsorption capacities of two binding sites were 65.21 and 189.83mgg(-1), and dissociation constants were 7.11 and 30.40μgmL(-1), respectively. The kinetic property of MMIPs was well fitted to the second-order equation. The selectivity experiment indicated that MMIPs had higher selectivity toward cyhalothrin and its structural analogs than reference compound. The feasibility of detecting pyrethroids from real samples was testified in spiked fruit samples with different concentrations (0.025, 0.25 and 2.5mgkg(-1)). The LODs of beta-cyfluthrin, cyhalothrin, cyphenothrin and permethrin were 0.0072, 0.0035, 0.0062 and 0.0068mgkg(-1), respectively. Precisions of intra-day and inter-day ranging from 2.6% to 4.3% and 4.2% to 5.6% were obtained, respectively. This method was applied to determine pyrethroids in different fruit samples including apple, pear, orange, grape and

  3. Development of magnetic resonance technology for noninvasive boron quantification

    International Nuclear Information System (INIS)

    Bradshaw, K.M.

    1990-11-01

    Boron magnetic resonance imaging (MRI) and spectroscopy (MRS) were developed in support of the noninvasive boron quantification task of the Idaho National Engineering Laboratory (INEL) Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) program. The hardware and software described in this report are modifications specific to a GE Signa trademark MRI system, release 3.X and are necessary for boron magnetic resonance operation. The technology developed in this task has been applied to obtaining animal pharmacokinetic data of boron compounds (drug time response) and the in-vivo localization of boron in animal tissue noninvasively. 9 refs., 21 figs

  4. Magnetic Tools for Lab-on-a-chip Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Pekas, Nikola Slobodan [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    This study establishes a set of magnetics-based tools that have been integrated with microfluidic systems. The overall impact of the work begins to enable the rapid and efficient manipulation and detection of magnetic entities such as particles, picoliter-sized droplets, or bacterial cells. Details of design, fabrication, and theoretical and experimental assessments are presented. The manipulation strategy has been demonstrated in the format of a particle diverter, whereby micron-sized particles are actively directed into desired flow channels at a split-flow junction by means of integrated microelectromagnets. Magnetic detection has been realized by deploying Giant Magnetoresistance (GMR) sensors--microfabricated structures originally developed for use as readout elements in computer hard-drives. We successfully transferred the GMR technology to the lab-on-a-chip arena, and demonstrated the versatility of the concept in several important areas: real-time, integrated monitoring of the properties of multiphase droplet flows; rapid quantitative determination of the concentration of magnetic nanoparticles in droplets of ferrofluids; and high-speed detection of individual magnetic microparticles and magnetotactic bacteria. The study also includes novel schemes for hydrodynamic flow focusing that work in conjunction with GMR-based detection to ensure precise navigation of the sample stream through the GMR detection volume, therefore effectively establishing a novel concept of a microfabricated magnetic flow cytometer.

  5. First-principles study of the stability, magnetic and electronic properties of Fe and Co monoatomic chains encapsulated into copper nanotube

    Science.gov (United States)

    Ma, Liang-Cai; Ma, Ling; Zhang, Jian-Min

    2017-07-01

    By using first-principles calculations based on density-functional theory, the stability, magnetic and electronic properties of Fe and Co monoatomic chains encapsulated into copper nanotube are systematically investigated. The binding energies of the hybrid structures are remarkably higher than those of corresponding freestanding TM chains, indicating the TM chains are significantly stabilized after encapsulating into copper nanotube. The formed bonds between outer Cu and inner TM atoms show some degree of covalent bonding character. The magnetic ground states of Fe@CuNW and Co@CuNW hybrid structures are ferromagnetic, and both spin and orbital magnetic moments of inner TM atoms have been calculated. The magnetocrystalline anisotropy energies (MAE) of the hybrid structures are enhanced by nearly fourfold compared to those of corresponding freestanding TM chains, indicating that the hybrid structures can be used in ultrahigh density magnetic storage. Furthermore, the easy magnetization axis switches from that along the axis in freestanding Fe chain to that perpendicular to the axis in Fe@CuNT hybrid structure. The large spin polarization at the Fermi level also makes the hybrid systems interesting as good potential materials for spintronic devices.

  6. Designing an optimum pulsed magnetic field by a resistance/self-inductance/capacitance discharge system and alignment of carbon nanotubes embedded in polypyrrole matrix

    Science.gov (United States)

    Kazemikia, Kaveh; Bonabi, Fahimeh; Asadpoorchallo, Ali; Shokrzadeh, Majid

    2015-02-01

    In this work, an optimized pulsed magnetic field production apparatus is designed based on a RLC (Resistance/Self-inductance/Capacitance) discharge circuit. An algorithm for designing an optimum magnetic coil is presented. The coil is designed to work at room temperature. With a minor physical reinforcement, the magnetic flux density can be set up to 12 Tesla with 2 ms duration time. In our design process, the magnitude and the length of the magnetic pulse are the desired parameters. The magnetic field magnitude in the RLC circuit is maximized on the basis of the optimal design of the coil. The variables which are used in the optimization process are wire diameter and the number of coil layers. The coil design ensures the critically damped response of the RLC circuit. The electrical, mechanical, and thermal constraints are applied to the design process. A locus of probable magnetic flux density values versus wire diameter and coil layer is provided to locate the optimum coil parameters. Another locus of magnetic flux density values versus capacitance and initial voltage of the RLC circuit is extracted to locate the optimum circuit parameters. Finally, the application of high magnetic fields on carbon nanotube-PolyPyrrole (CNT-PPy) nano-composite is presented. Scanning probe microscopy technique is used to observe the orientation of CNTs after exposure to a magnetic field. The result shows alignment of CNTs in a 10.3 Tesla, 1.5 ms magnetic pulse.

  7. Alignment of Carbon Nanotubes Comprising Magnetically Sensitive Metal Oxides in Nanofluids

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G. P. " Bud" (Inventor)

    2016-01-01

    The present invention is a nanoparticle mixture or suspension or nanofluid comprising nonmagnetically sensitive nanoparticles, magnetically sensitive nanoparticles, and surfactant(s). The present invention also relates to methods of preparing and using the same.

  8. Characterization of magnetic soluble starch-functionalized carbon nanotubes and its application for the adsorption of the dyes

    International Nuclear Information System (INIS)

    Chang, Peter R.; Zheng Pengwu; Liu Baoxiang; Anderson, Debbie P.; Yu Jiugao; Ma Xiaofei

    2011-01-01

    Soluble starch-functionalized multiwall carbon nanotube composites (MWCNT-starch) were prepared to improve the hydrophilicity and biocompatibility of MWCNTs. Characterization of the MWCNT-starch by Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM) and thermogravimetric analysis (TG), showed that the starch component (about 14.3 wt%) was covalently grafted onto the surface of MWCNT. MWCNT-starch-iron oxide composites, intended for use as adsorbents for the removal of dyes from aqueous solutions, were prepared by synthesizing iron oxide nanoparticles at the surface of MWCNT-starch. Starch acts as a template for growth of iron oxide nanoparticles which are uniformly dispersed on the surface of the MWCNT-starch. MWCNT-starch-iron oxide exhibits superparamagnetic properties with a saturation magnetization (23.15 emu/g) and better adsorption for anionic methyl orange (MO) and cationic methylene blue (MB) dyes than MWCNT-iron oxide.

  9. Thermoelectric power in ultrathin films, quantum wires and carbon nanotubes under classically large magnetic field: Simplified theory and relative comparison

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.; Choudhury, S. [Electronics and Communication Engineering, Sikkim Manipal Institute of Technology, Majitar, East Sikkim 737 132 (India); Saha, S. [Electronics and Communication Engineering, Mallabhum Institute of Technology College Campus, Brajaradhanagar, P.O. Gosaipur, P.S. Bishnupur, District - Bankura 722 122 (India); Pahari, S. [Administration Department, Jadavpur University, Kolkata 700 032 (India); De, D. [Department of Computer Science Engineering, West Bengal University of Technology, BF 142, Sector 1, Kolkatta 700 064, West Bengal (India); Bhattacharya, S. [Nano Scale Device Research Laboratory, Center for Electronics Design and Technology, Indian Institute of Science, Bangalore 560 012 (India); Ghatak, K.P., E-mail: kamakhyaghatak@yahoo.co.i [Department of Electronic Science, University Calcutta, 92 Acharyya Prafulla Chandra Road, Kolkata 700 009 (India)

    2010-01-01

    We study the thermoelectric power under classically large magnetic field (TPM) in ultrathin films (UFs), quantum wires (QWs) of non-linear optical materials on the basis of a newly formulated electron dispersion law considering the anisotropies of the effective electron masses, the spin-orbit splitting constants and the presence of the crystal field splitting within the framework of k.p formalism. The results of quantum confined III-V compounds form the special cases of our generalized analysis. The TPM has also been studied for quantum confined II-VI, stressed materials, bismuth and carbon nanotubes (CNs) on the basis of respective dispersion relations. It is found taking quantum confined CdGeAs{sub 2}, InAs, InSb, CdS, stressed n-InSb and Bi that the TPM increases with increasing film thickness and decreasing electron statistics exhibiting quantized nature for all types of quantum confinement. The TPM in CNs exhibits oscillatory dependence with increasing carrier concentration and the signature of the entirely different types of quantum systems are evident from the plots. Besides, under certain special conditions, all the results for all the materials gets simplified to the well-known expression of the TPM for non-degenerate materials having parabolic energy bands, leading to the compatibility test.

  10. Reinforced carbon fiber laminates with oriented carbon nanotube epoxy nanocomposites: Magnetic field assisted alignment and cryogenic temperature mechanical properties.

    Science.gov (United States)

    He, Yuxin; Yang, Song; Liu, Hu; Shao, Qian; Chen, Qiuyu; Lu, Chang; Jiang, Yuanli; Liu, Chuntai; Guo, Zhanhu

    2018-05-01

    The epoxy nanocomposites with ordered multi-walled carbon nanotubes (MWCNTs) were used to influence the micro-cracks resistance of carbon fiber reinforced epoxy (CF/EP) laminate at 77 K, Oxidized MWCNTs functionalized with Fe 3 O 4 (Fe 3 O 4 /O-MWCNTs) with good magnetic properties were prepared by co-precipitation method and used to modify epoxy (EP) for cryogenic applications. Fe 3 O 4 /O-MWCNTs reinforced carbon fiber epoxy composites were also prepared through vacuum-assisted resin transfer molding (VARTM). The ordered Fe 3 O 4 /O-MWCNTs were observed to have effectively improved the mechanical properties of epoxy (EP) matrix at 77 K and reduce the coefficient of thermal expansion (CTE) of EP matrix. The ordered Fe 3 O 4 /O-MWCNTs also obviously improved the micro-cracks resistance of CF/EP composites at 77 K. Compared to neat EP, the CTE of ordered Fe 3 O 4 /O-MWCNTs modified CF/EP composites was decreased 37.6%. Compared to CF/EP composites, the micro-cracks density of ordered Fe 3 O 4 /O-MWCNTs modified CF/EP composites at 77 K was decreased 37.2%. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Evaluation of airborne thermal, magnetic, and electromagnetic characterization technologies

    International Nuclear Information System (INIS)

    Josten, N.E.

    1992-03-01

    The identification of Buried Structures (IBS) or Aerial Surveillance Project was initiated by the US Department of Energy (DOE) Office of Technology Development to demonstrate airborne methods for locating and identifying buried waste and ordnance at the Idaho National Engineering Laboratory (INEL). Two technologies were demonstrated: (a) a thermal infrared imaging system built by Martin Marietta Missile Systems and (b) a magnetic and electromagnetic (EM) geophysical surveying system operated by EBASCO Environmental. The thermal system detects small differences in ground temperature caused by uneven heating and cooling of the ground by the sun. Waste materials on the ground can be detected when the temperature of the waste is different than the background temperature. The geophysical system uses conventional magnetic and EM sensors. These sensors detect disturbances caused by magnetic or conductive waste and naturally occurring magnetic or conductive features of subsurface soils and rock. Both systems are deployed by helicopter. Data were collected at four INEL sites. Tests at the Naval Ordnance Disposal Area (NODA) were made to evaluate capabilities for detecting ordnance on the ground surface. Tests at the Cold Simulated Waste Demonstration Pit were made to evaluate capabilities for detecting buried waste at a controlled site, where the location and depth of buried materials are known. Tests at the Subsurface Disposal Area and Stationary Low-Power Reactor-1 burial area were made to evaluate capabilities for characterizing hazardous waste at sites that are typical of DOE buried waste sites nationwide

  12. Evaluation of airborne thermal, magnetic, and electromagnetic characterization technologies

    Energy Technology Data Exchange (ETDEWEB)

    Josten, N.E.

    1992-03-01

    The identification of Buried Structures (IBS) or Aerial Surveillance Project was initiated by the US Department of Energy (DOE) Office of Technology Development to demonstrate airborne methods for locating and identifying buried waste and ordnance at the Idaho National Engineering Laboratory (INEL). Two technologies were demonstrated: (a) a thermal infrared imaging system built by Martin Marietta Missile Systems and (b) a magnetic and electromagnetic (EM) geophysical surveying system operated by EBASCO Environmental. The thermal system detects small differences in ground temperature caused by uneven heating and cooling of the ground by the sun. Waste materials on the ground can be detected when the temperature of the waste is different than the background temperature. The geophysical system uses conventional magnetic and EM sensors. These sensors detect disturbances caused by magnetic or conductive waste and naturally occurring magnetic or conductive features of subsurface soils and rock. Both systems are deployed by helicopter. Data were collected at four INEL sites. Tests at the Naval Ordnance Disposal Area (NODA) were made to evaluate capabilities for detecting ordnance on the ground surface. Tests at the Cold Simulated Waste Demonstration Pit were made to evaluate capabilities for detecting buried waste at a controlled site, where the location and depth of buried materials are known. Tests at the Subsurface Disposal Area and Stationary Low-Power Reactor-1 burial area were made to evaluate capabilities for characterizing hazardous waste at sites that are typical of DOE buried waste sites nationwide.

  13. Combination of Polymer Technology and Carbon Nanotube Array for the Development of an Effective Drug Delivery System at Cellular Level

    Directory of Open Access Journals (Sweden)

    Riggio Cristina

    2009-01-01

    Full Text Available Abstract In this article, a carbon nanotube (CNT array-based system combined with a polymer thin film is proposed as an effective drug release device directly at cellular level. The polymeric film embedded in the CNT array is described and characterized in terms of release kinetics, while in vitro assays on PC12 cell line have been performed in order to assess the efficiency and functionality of the entrapped agent (neural growth factor, NGF. PC12 cell differentiation, following incubation on the CNT array embedding the alginate delivery film, demonstrated the effectiveness of the proposed solution. The achieved results indicate that polymeric technology could be efficiently embedded in CNT array acting as drug delivery system at cellular level. The implication of this study opens several perspectives in particular in the field of neurointerfaces, combining several functions into a single platform.

  14. Superconducting magnetic energy storage (SMES). Results of a technology assessment

    International Nuclear Information System (INIS)

    Fleischer, T.; Juengst, K.P.; Brandl, V.; Maurer, W.; Nieke, E.

    1995-05-01

    The authors report on results of a Technology Assessment study commissioned by the German Federal Ministry of Education, Science, Research and Technology. The objective of this study was to evaluate the potential of superconducting magnetic energy storage (SMES) technology with respect to the economical, political and organization structures in the Federal Republic of Germany. The main focus of the study was on the technical and economic potential of large-scale SMES for diurnal load levelling applications. It was shown that there is no demand for the development of large SMES in Germany in the short and medium term. A second range of applications investigated is storage of electric energy for immediate delivery or consumption of electric power in case of need or for periodic power supply within the range of seconds. Due to its excellent dynamic properties SMES has substantial advantages over conventional storage technologies in this field. For those so-called dynamic applications SMES of small and medium energy capacity are needed. It was shown that SMES may be economically attractive for the provision of spinning reserve capacity in electrical networks, in particular cases for power quality applications (uninterruptable power supply, UPS) and for the compensation of cyclic loads, as well as in some market niches. The use of SMES for storage of recuperated energy in electrical railway traction systems has been proven to be uneconomical. Mobile SMES applications are unrealistic due to technical and size limitations. In SMES systems the energy is stored in a magnetic field. Biological objects as well as technical systems in the vicinity of a SMES plant are exposed to this field. The knowledge on impacts of magnetic fields on sensitive technical systems as well as on living organisms and especially on effects on human health is rather small and quite uncertain. (orig./MM) [de

  15. Magnetic Probe Construction using Thick-film Technology

    International Nuclear Information System (INIS)

    Takahashi, H.; Sakakibara, S.; Kubota, Y.; Yamada, H.

    2001-01-01

    Thick-film technology has been successfully adapted for the design and fabrication of magnetic probes of a new type suitable for use in the simultaneous ultra-high vacuum and high-temperature environment of a nuclear fusion device. The maximum usable temperature is expected to be around 900 degrees C. This new probe has a specific sensitivity (coupling area per unit volume) an order of magnitude higher than a conventional coil. The new probe in one implementation is capable of simultaneously measuring magnetic field in three orthogonal directions about a single spatial point and in two frequency ranges. Low-frequency coils have a measured coupling area of 296-323 cm squared and a frequency response of about 300 kHz. High-frequency coils have a design coupling area of 12-15 cm squared

  16. Status of tritium technology development for magnetic-fusion energy

    International Nuclear Information System (INIS)

    Anderson, J.L.

    1983-01-01

    The development of tritium technology for the magnetic fusion energy program has progressed at a rapid rate over the past two years. The focal points for this development in the United States have been the Tritium Systems Test Assembly at Los Alamos and the FED/INTOR studies supported by the Fusion Engineering Design Center at Oak Ridge. In Canada the Canadian Fusion Fuel Technology Project has been initiated and promises to make significant contributions to the tritium technology program in the next few years. The Japanese government has now approved funding for the Tritium Processing Laboratory at the Japan Atomic Energy Research Institute's Tokai Research Establishment. Construction on this new facility is scheduled to begin in April 1983. This facility will be the center for fusion tritium technology development in Japan. The European Community is currently working on the design of the tritium facility for the Joint European Torus. There is considerable interaction between all of these programs, thus accelerating the overall development of this crucial technology

  17. Development of Novel Magnetic Metal Oxide Thin Films and Carbon Nanotube Materials for Potential Device Applications

    Science.gov (United States)

    2016-05-09

    9 3 Fe/MWCNTs/ SiO2 and Nano...magnetization measurements -1.5 0.0 1.5 To rq ue (a .u .) IP H = 1.9 T CoFe2 on glass in-Field -1.5 0.0 1.5 To rq ue (a . u .) 360300240180120600 Field Angle...deg.) IP H = 1.9 T CoFe2 on glass no-Field a b Fig. 2.3: Torque magnetometry for CoFe2 layer deposited (a) in-field and (b) deposited with no

  18. Ozone-assisted Regeneration of Magnetic Carbon Nanotubes for Removing Organic Water Pollutants

    DEFF Research Database (Denmark)

    Ateia, Mohamed; Ceccato, Marcel; Budi, Akin

    2018-01-01

    (MCNTs) after they have been used to remove organic pollutants from water. We ran MCNT through multiple regeneration cycles (i.e. magnetic collection → ozone regeneration → washing with ethanol then water) to adsorb atrazine. The results of our adsorption experiments show that the atrazine removal...... consecutive regeneration cycles. Additionally, we used a three layer graphite slab as a model system for CNTs and performed density functional theory (DFT) calculations to determine the free energy of adsorption and the free energy of solvation of atrazine and its byproducts in water and ethanol. The results...

  19. Characterization of carbon nanotubes decorated with NiFe2O4 magnetic nanoparticles as a novel electrochemical sensor: Application for highly selective determination of sotalol using voltammetry

    International Nuclear Information System (INIS)

    Ensafi, Ali A.; Allafchian, Ali R.; Rezaei, B.; Mohammadzadeh, R.

    2013-01-01

    A magnetic nano‐composite of multiwall carbon nanotube, decorated with NiFe 2 O 4 nanoparticles, was synthesized with citrate sol–gel method. The multiwall carbon nanotubes decorated with NiFe 2 O 4 nanoparticles (NiFe 2 O 4 –MWCNTs) were characterized with different methods such as Fourier transform infrared spectroscopy (FT‐IR), transmission electron microscopy (TEM), atomic force microscopy (AFM), vibrating sample magnetometer (VSM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The new nano-composite acts as a suitable electrocatalyst for the oxidation of sotalol at a potential of 500 mV at the surface of the modified electrode. Linear sweep voltammetry exhibited two wide linear dynamic ranges of 0.5–1000 μmol L −1 sotalol with a detection limit of 0.09 μmol L −1 . The modified electrode was used as a novel electrochemical sensor for the determination of sotalol in real samples such as pharmaceutical, patient and safe human urine. - Graphical abstract: Multiwall carbon nanotube, decorated with NiFe 2 O 4 nanoparticles, was prepared using citrate sol–gel method. We characterized the new nanoparticles with different spectroscopic and voltammetric methods. The nano sensor was used as a voltammetric sensor for the determination of trace amounts of sotalol at pH 7.0. Highlights: ► We synthesized and prepared new sensor, multiwall carbon nanotubes decorated with NiFe 2 O 4 . ► Several spectroscopic and voltammetric methods were used to study its characteristics. ► The nanoparticles act as suitable electrocatalyst for the oxidation of sotalol. ► Sotalol could be measured as low as 0.09 μmol L −1 using linear sweep voltammetry.

  20. Thermal behavior of dynamic magnetizations, hysteresis loop areas and correlations of a cylindrical Ising nanotube in an oscillating magnetic field within the effective-field theory and the Glauber-type stochastic dynamics approach

    International Nuclear Information System (INIS)

    Deviren, Bayram; Keskin, Mustafa

    2012-01-01

    The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.

  1. Thermal behavior of dynamic magnetizations, hysteresis loop areas and correlations of a cylindrical Ising nanotube in an oscillating magnetic field within the effective-field theory and the Glauber-type stochastic dynamics approach

    Energy Technology Data Exchange (ETDEWEB)

    Deviren, Bayram, E-mail: bayram.deviren@nevsehir.edu.tr [Department of Physics, Nevsehir University, 50300 Nevsehir (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

    2012-02-20

    The dynamical aspects of a cylindrical Ising nanotube in the presence of a time-varying magnetic field are investigated within the effective-field theory with correlations and Glauber-type stochastic approach. Temperature dependence of the dynamic magnetizations, dynamic total magnetization, hysteresis loop areas and correlations are investigated in order to characterize the nature of dynamic transitions as well as to obtain the dynamic phase transition temperatures and compensation behaviors. Some characteristic phenomena are found depending on the ratio of the physical parameters in the surface shell and core, i.e., five different types of compensation behaviors in the Néel classification nomenclature exist in the system. -- Highlights: ► Kinetic cylindrical Ising nanotube is investigated using the effective-field theory. ► The dynamic magnetizations, hysteresis loop areas and correlations are calculated. ► The effects of the exchange interactions have been studied in detail. ► Five different types of compensation behaviors have been found. ► Some characteristic phenomena are found depending on ratio of physical parameters.

  2. Technologies for the 21st century: carbon nanotubes as adsorbents of metals

    Directory of Open Access Journals (Sweden)

    Alguacil, Francisco José

    2014-09-01

    Full Text Available Nowadays and in the recent past when the word “nano” appeared in almost anything it attracted immediate attention and interest, this is why carbon nanotubes, since its discovery nearly twenty years ago, caught the interest of a wide scientific and industrial population to apply the somewhat amazing properties of these nanomaterials in a number of applications. Among them, the removal of toxic and sometimes profitable metals from aqueous streams appeared, due to its economical and social impact, as one of the targets for their uses. This paper reviews some recent advances (2009–2013 years in the application of carbon nanotubes materials in the removal of a variety of metals from these aqueous streams.Tanto en el pasado como hoy en día, cuando la palabra “nano” aparece en cualquier sitio inmediatamente suscita atención e interés; por eso y desde su descubrimiento hace cerca de veinte años, los nanotubos de carbono interesaron tanto a científicos como a industriales, que utilizaron las propiedades de estos nanomateriales en una serie de aplicaciones. Entre éstas, se incluye la eliminación de metales tóxicos, y otros con un cierto valor económico, de medios acuosos, problemática que además tiene unas implicaciones económicas y sociales importantes. Este trabajo revisa los avances más recientes (años 2009–2013 de la utilización de estos nanotubos de carbono en la eliminación de una serie de metales contenidos en distintos medios acuosos.

  3. Technology of magnetic abrasive finishing in machining of difficult-to-machine alloy complex surface

    Directory of Open Access Journals (Sweden)

    Fujian MA

    2016-10-01

    Full Text Available The technology of magnetic abrasive finishing is one of the important finishing technologies. Combining with low-frequency vibration and ultrasonic vibration, it can attain higher precision, quality and efficiency. The characteristics and the related current research of magnetic abrasive finishing, vibration assisted magnetic abrasive finishing and ultrasonic assisted magnetic abrasive finishing are introduced. According to the characteristics of the difficult-to-machine alloy's complex surface, the important problems for further study are presented to realize the finishing of complex surface with the technology of magnetic abrasive finishing, such as increasing the machining efficiency by enhancing the magnetic flux density of machining gap and compounding of magnetic energy and others, establishing of the control function during machining and the process planning method for magnetic abrasive finishing of complex surface under the space geometry restraint of complex surface on magnetic pole, etc.

  4. Magnetic MoS2 on multiwalled carbon nanotubes for sulfide sensing.

    Science.gov (United States)

    Li, Chunxiang; Zhang, Dan; Wang, Jiankang; Hu, Pingan; Jiang, Zhaohua

    2017-07-04

    A novel hybrid metallic cobalt insided in multiwalled carbon nanotubles/molybdenum disulfide (Co@CNT/MoS 2 ) modified glass carbon electrode (GCE) was fabricated with a adhesive of Nafion suspension and used as chemical sensors for sulfide detection. Single-layered MoS 2 was coated on CNTs through magnetic traction force between paramagnetic monolayer MoS 2 and Co particles in CNTs. Co particles faciliated the collection of paramagnetic monolayer MoS 2 exfoliated from bulk MoS 2 in solution. Amperometric analysis, cycle voltammetry, cathodic stripping analysis and linear sweep voltammetry results showed the Co@CNT/MoS 2 modified GCE exhibited excellent electrochemical activity to sulfide in buffer solutions, but amperometric analysis was found to be more sensitive than the other methods. The amperometric response result indicated the Co@CNT/MoS 2 -modified GCE electrode was an excellent electrochemical sensor for detecting S 2- with a detection limit of 7.6 nM and sensitivity of 0.23 mA/μM. The proposed electrode was used for the determination of sulfide levels in hydrogen sulfide-pretreated fruits, and the method was also verified with recovery studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Magnetic solid-phase extraction based on carbon nanotubes for the determination of polyether antibiotic and s-triazine drug residues in animal food with LC-MS/MS.

    Science.gov (United States)

    Liu, Xiaoxing; Xie, Shuyu; Ni, Tengteng; Chen, Dongmei; Wang, Xu; Pan, Yuanhu; Wang, Yulian; Huang, Lingli; Cheng, Guyue; Qu, Wei; Liu, Zhenli; Tao, Yanfei; Yuan, Zonghui

    2017-06-01

    Carbon nanotubes-magnetic nanoparticles, comprising ferroferric oxide nanoparticles and carbon nanotubes, were prepared through a simple one-step synthesis method and subsequently applied to magnetic solid-phase extraction for the determination of polyether antibiotic and s-triazine drug residues in animal food coupled with liquid chromatography with tandem mass spectrometry. The nanocomposites were characterized by transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The components within the nanocomposites endowed the material with high extraction performance and manipulative convenience. Compared with carbon nanotubes, the as-prepared carbon nanotubes-magnetic nanoparticles showed better extraction and separation efficiencies for polyether antibiotics and s-triazine drugs thanks to the contribution of the iron-containing magnetic nanoparticles. Various experimental parameters affecting the extraction efficiency had been investigated in detail. Under the optimal conditions, the good linearity ranging from 1 to 200 μg/kg for diclazuril, toltrazuril, toltrazuril sulfone, lasalocid, monensin, salinomycin, narasin, nanchangmycin, and maduramicin, low limits of detection ranging from 1 to 5 μg/kg, and satisfactory spiked recoveries (77.1-91.2%, with the inter relative standard deviation values from 4.0 to 12.2%) were shown. It was confirmed that this novel method was an efficient pretreatment and enrichment procedure and could be successfully applied for extraction and determination of polyether and s-triazine drug residues in complex matrices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. New Effective Material Couple--Oxide Ceramic and Carbon Nanotube-- Developed for Aerospace Microsystem and Micromachine Technologies

    Science.gov (United States)

    Miyoshi, Kazuhisa; VanderWal, Randall L.; Tomasek, Aaron J.; Sayir, Ali; Farmer, Serene C.

    2004-01-01

    The prime driving force for using microsystem and micromachine technologies in transport vehicles, such as spacecraft, aircraft, and automobiles, is to reduce the weight, power consumption, and volume of components and systems to lower costs and increase affordability and reliability. However, a number of specific issues need to be addressed with respect to using microsystems and micromachines in aerospace applications--such as the lack of understanding of material characteristics; methods for producing and testing the materials in small batches; the limited proven durability and lifetime of current microcomponents, packaging, and interconnections; a cultural change with respect to system designs; and the use of embedded software, which will require new product assurance guidelines. In regards to material characteristics, there are significant adhesion, friction, and wear issues in using microdevices. Because these issues are directly related to surface phenomena, they cannot be scaled down linearly and they become increasingly important as the devices become smaller. When microsystems have contacting surfaces in relative motion, the adhesion and friction affect performance, energy consumption, wear damage, maintenance, lifetime and catastrophic failure, and reliability. Ceramics, for the most part, do not have inherently good friction and wear properties. For example, coefficients of friction in excess of 0.7 have been reported for ceramics and ceramic composite materials. Under Alternate Fuels Foundation Technologies funding, two-phase oxide ceramics developed for superior high-temperature wear resistance in NASA's High Operating Temperature Propulsion Components (HOTPC) project and new two-layered carbon nanotube (CNT) coatings (CNT topcoat/iron bondcoat/quartz substrate) developed in NASA's Revolutionary Aeropropulsion Concepts (RAC) project have been chosen as a materials couple for aerospace applications, including micromachines, in the nanotechnology

  7. Modification of polydopamine-coated Fe3O4 nanoparticles with multi-walled carbon nanotubes for magnetic-μ-dispersive solid-phase extraction of antiepileptic drugs in biological matrices.

    Science.gov (United States)

    Zhang, Ruiqi; Wang, Siming; Yang, Ye; Deng, Yulan; Li, Di; Su, Ping; Yang, Yi

    2018-06-01

    In this study, multi-walled carbon nanotubes were coated on the surface of magnetic nanoparticles modified by polydopamine. The synthesized composite was characterized and applied to magnetic-μ-dispersive solid-phase extraction of oxcarbazepine (OXC), phenytoin (PHT), and carbamazepine (CBZ) from human plasma, urine, and cerebrospinal fluid samples prior to analysis by a high-performance liquid chromatography-photodiode array detector. The extraction parameters were investigated and the optimum condition was obtained when the variables were set to the following: sorbent type, Fe 3 O 4 @polyDA-MWCNTs (length Graphical abstract Magnetic multi-walled carbon nanotube core-shell composites were applied as magnetic-μ-dispersive solid-phase extraction adsorbents for determination of antiepileptic drugs in biological matrices.

  8. Improved microwave shielding behavior of carbon nanotube-coated PET fabric using plasma technology

    Energy Technology Data Exchange (ETDEWEB)

    Haji, Aminoddin, E-mail: Ahaji@iaubir.ac.ir [Department of Textile Engineering, Birjand Branch, Islamic Azad University, Birjand (Iran, Islamic Republic of); Semnani Rahbar, Ruhollah [Department of Textile and Leather, Faculty of Chemistry and Petrochemical Engineering, Standard Research Institute, Karaj (Iran, Islamic Republic of); Mousavi Shoushtari, Ahmad [Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2014-08-30

    Four different procedures were conducted to load amine functionalized multiwall carbon nanotube (NH{sub 2}-MWCNT) onto poly (ethylene terephthalate) (PET) fabric surface to obtain a microwave shielding sample. Plasma treated fabric which was subsequently coated with NH{sub 2}-MWCNT in the presence of acrylic acid was chosen as the best sample. Surface changes in the PET fabrics were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Wide-angle X-ray diffraction was used to study the crystalline structure of the PET fabric. The microwave shielding performance of the PET fabrics in term of reflection loss was determined using a network analyzer at X-band (8.2–12.4 GHz). The XPS results revealed that the carbon atomic percentage decreased while the oxygen atomic percentage increased when the fabric was plasma treated and coated with NH{sub 2}-MWCNT. The SEM images showed that the NH{sub 2}-MWCNTs were homogenously dispersed and individually separated in the surface of fabric. Moreover, the structural studies showed that the crystalline region of the fabrics was not affected by NH{sub 2}-MWCNT and plasma treatment. The best microwave absorbing properties were obtained from the plasma treated fabric which was then coated with 10% NH{sub 2}-MWCNT in the presence of acrylic acid. It showed a minimum reflection loss of ∼−18.2 dB about 11 GHz. Proper attachments of NH{sub 2}-MWCNT on the PET fabric surface was explained in the suggested mechanism in which hydrogen bonding and amide linkage are responsible for the achievement of microwave shielding properties with high durability.

  9. Improved microwave shielding behavior of carbon nanotube-coated PET fabric using plasma technology

    International Nuclear Information System (INIS)

    Haji, Aminoddin; Semnani Rahbar, Ruhollah; Mousavi Shoushtari, Ahmad

    2014-01-01

    Four different procedures were conducted to load amine functionalized multiwall carbon nanotube (NH 2 -MWCNT) onto poly (ethylene terephthalate) (PET) fabric surface to obtain a microwave shielding sample. Plasma treated fabric which was subsequently coated with NH 2 -MWCNT in the presence of acrylic acid was chosen as the best sample. Surface changes in the PET fabrics were investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Wide-angle X-ray diffraction was used to study the crystalline structure of the PET fabric. The microwave shielding performance of the PET fabrics in term of reflection loss was determined using a network analyzer at X-band (8.2–12.4 GHz). The XPS results revealed that the carbon atomic percentage decreased while the oxygen atomic percentage increased when the fabric was plasma treated and coated with NH 2 -MWCNT. The SEM images showed that the NH 2 -MWCNTs were homogenously dispersed and individually separated in the surface of fabric. Moreover, the structural studies showed that the crystalline region of the fabrics was not affected by NH 2 -MWCNT and plasma treatment. The best microwave absorbing properties were obtained from the plasma treated fabric which was then coated with 10% NH 2 -MWCNT in the presence of acrylic acid. It showed a minimum reflection loss of ∼−18.2 dB about 11 GHz. Proper attachments of NH 2 -MWCNT on the PET fabric surface was explained in the suggested mechanism in which hydrogen bonding and amide linkage are responsible for the achievement of microwave shielding properties with high durability

  10. Superconducting Magnet Technology for Future High Energy Proton Colliders

    Science.gov (United States)

    Gourlay, Stephen

    2017-01-01

    Interest in high field dipoles has been given a boost by new proposals to build a high-energy proton-proton collider to follow the LHC and programs around the world are taking on the task to answer the need. Studies aiming toward future high-energy proton-proton colliders at the 100 TeV scale are now being organized. The LHC and current cost models are based on technology close to four decades old and point to a broad optimum of operation using dipoles with fields between 5 and 12T when site constraints, either geographical or political, are not a factor. Site geography constraints that limit the ring circumference can drive the required dipole field up to 20T, which is more than a factor of two beyond state-of-the-art. After a brief review of current progress, the talk will describe the challenges facing future development and present a roadmap for moving high field accelerator magnet technology forward. This work was supported by the Director, Office of Science, High Energy Physics, US Department of Energy, under contract No. DE-AC02-05CH11231.

  11. Mechanically Robust Magnetic Carbon Nanotube Papers Prepared with CoFe2O4 Nanoparticles for Electromagnetic Interference Shielding and Magnetomechanical Actuation.

    Science.gov (United States)

    Lim, Guh-Hwan; Woo, Seongwon; Lee, Hoyoung; Moon, Kyoung-Seok; Sohn, Hiesang; Lee, Sang-Eui; Lim, Byungkwon

    2017-11-22

    The introduction of inorganic nanoparticles into carbon nanotube (CNT) papers can provide a versatile route to the fabrication of CNT papers with diverse functionalities, but it may lead to a reduction in their mechanical properties. Here, we describe a simple and effective strategy for the fabrication of mechanically robust magnetic CNT papers for electromagnetic interference (EMI) shielding and magnetomechanical actuation applications. The magnetic CNT papers were produced by vacuum filtration of an aqueous suspension of CNTs, CoFe 2 O 4 nanoparticles, and poly(vinyl alcohol) (PVA). PVA plays a critical role in enhancing the mechanical strength of CNT papers. The magnetic CNT papers containing 73 wt % of CoFe 2 O 4 nanoparticles exhibited high mechanical properties with Young's modulus of 3.2 GPa and tensile strength of 30.0 MPa. This magnetic CNT paper was successfully demonstrated as EMI shielding paper with shielding effectiveness of ∼30 dB (99.9%) in 0.5-1.0 GHz, and also as a magnetomechanical actuator in an audible frequency range from 200 to 20 000 Hz.

  12. A novel magnetic ionic liquid modified carbon nanotube for the simultaneous determination of aryloxyphenoxy-propionate herbicides and their metabolites in water

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Mai; Liu, Donghui; Zhao, Lu; Han, Jiajun; Liang, Yiran; Wang, Peng; Zhou, Zhiqiang, E-mail: zqzhou@cau.edu.cn

    2014-12-10

    Highlights: • A new kind of ionic liquid modified carbon nanotube has been synthesized and applied for simultaneous analysis of AOPPs and their metabolites. • The potential pollutants, such as metabolites of AOPPs, have been analyzed. • The mechanism of absorption has been discussed. • Varieties of experiment factors were optimized and selected. • This method has been successfully applied in the analysis of real water samples. - Abstract: A reliable, sensitive, rapid and environmentally friendly analysis procedure for the simultaneous determination of the analytes with a wide range of polarity in the environmental water was developed by coupling dispersive magnetic solid-phase extraction (d-MSPE) with high-performance liquid chromatography (HPLC)–diode array detector (DAD) and ultra-high pressure liquid chromatography (UHPLC)-triple quadrupole mass spectrometer (MS/MS), in this work. Magnetic ionic liquid modified multi-walled carbon nanotubes (m-IL-MWCNTs) were prepared by spontaneous assembly of magnetic nanoparticles and imidazolium-modified carbon nanotubes, and used as the sorbent of d-MSPE to simultaneously extract aryloxyphenoxy-propionate herbicides (AOPPs) and their polar acid metabolites due to the excellent π–π electron donor–acceptor interactions and anion exchange ability. The factors, including the amount of sorbent, pH of the sample solution, extraction time and the volume of elution solvent were investigated. Under the optimized conditions, the proposed d-MSPE coupling to HPLC–DAD system had a satisfactory performance, the limits of detection (LODs, defined as the signal to noise ratio of 3) and the limits of quantification (LOQs, defined as the signal to noise ratio of 10) for analytes in Milli-Q water were in the range of 2.8–14.3 and 9.8–43.2 μg L{sup −1} respectively. Calibration curves were linear (r{sup 2} > 0.998) over the concentration range from 0.02 to 1 mg L{sup −1}. The recoveries of the eight analytes ranged

  13. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  14. Near-infrared magneto-optical study of excitonic states in single-walled carbon nanotubes under ultra-high magnetic fields

    International Nuclear Information System (INIS)

    Yokoi, H; Effendi, Mukhtar; Minami, N; Takeyama, S

    2011-01-01

    Singlet excitonic states at the first subband-edge in single-walled carbon nanotubes (SWCNTs) have been studied through near-infrared magneto-absorption spectroscopy under magnetic fields to 105.9 T. Well-resolved absorption spectra of stretch-aligned SWCNT(CoMoCAT)-gelatin films were obtained above 100 T. By the application of magnetic fields in parallel to the alignment of SWCNTs, peak shift toward the lower energy was observed for (8, 4) and (7, 6) tubes and the opposite behavior was observed for (7, 5) and (6, 5) tubes. Above 28.8 T, new peaks emerged at the higher energy side of the peak for the (8, 4) and (7, 6) tubes, and at the lower energy side of the peaks for the (7, 5) and (6, 5) tubes. The magnetic splitting between the existing peak and the new peak was symmetric for every tube, which is in line with the energy splitting due to the Aharonov-Bohm effect. Judging from the energetic positions where the new peaks emerged, the singlet dark excitonic state locates at the lower energy than the singlet bright one in the (7, 5) and (6, 5) tubes while it is suggested strongly that the bright one locates at the lower energy in the (8, 4) and (7, 6) tubes.

  15. Magnetic super-hydrophilic carbon nanotubes/graphene oxide composite as nanocarriers of mesenchymal stem cells: Insights into the time and dose dependences.

    Science.gov (United States)

    Granato, Alessandro E C; Rodrigues, Bruno V M; Rodrigues-Junior, Dorival M; Marciano, Fernanda R; Lobo, Anderson O; Porcionatto, Marimelia A

    2016-10-01

    Among nanostructured materials, multi-walled carbon nanotubes (MWCNT) have demonstrated great potential for biomedical applications in recent years. After oxygen plasma etching, we can obtain super-hydrophilic MWCNT that contain graphene oxide (GO) at their tips. This material exhibits good dispersion in biological systems due to the presence of polar groups and its excellent magnetic properties due to metal particle residues from the catalyst that often remain trapped in its walls and tips. Here, we show for the first time a careful biological investigation using magnetic superhydrophilic MWCNT/GO (GCN composites). The objective of this study was to investigate the application of GCN for the in vitro immobilization of mesenchymal stem cells. Our ultimate goal was to develop a system to deliver mesenchymal stem cells to different tissues and organs. We show here that mesenchymal stem cells were able to internalize GCN with a consequent migration when subjected to a magnetic field. The cytotoxicity of GCN was time- and dose-dependent. We also observed that GCN internalization caused changes in the gene expression of the proteins involved in cell adhesion and migration, such as integrins, laminins, and the chemokine CXCL12, as well as its receptor CXCR4. These results suggest that GCN represents a potential new platform for mesenchymal stem cell immobilization at injury sites. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Wave propagation in fluid-conveying viscoelastic carbon nanotubes under longitudinal magnetic field with thermal and surface effect via nonlocal strain gradient theory

    Science.gov (United States)

    Zhen, Yaxin; Zhou, Lin

    2017-03-01

    Based on nonlocal strain gradient theory, wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes (SWCNTs) is studied in this paper. With consideration of thermal effect and surface effect, wave equation is derived for fluid-conveying viscoelastic SWCNTs under longitudinal magnetic field utilizing Euler-Bernoulli beam theory. The closed-form expressions are derived for the frequency and phase velocity of the wave motion. The influences of fluid flow velocity, structural damping coefficient, temperature change, magnetic flux and surface effect are discussed in detail. SWCNTs’ viscoelasticity reduces the wave frequency of the system and the influence gets remarkable with the increase of wave number. The fluid in SWCNTs decreases the frequency of wave propagation to a certain extent. The frequency (phase velocity) gets larger due to the existence of surface effect, especially when the diameters of SWCNTs and the wave number decrease. The wave frequency increases with the increase of the longitudinal magnetic field, while decreases with the increase of the temperature change. The results may be helpful for better understanding the potential applications of SWCNTs in nanotechnology.

  17. Fabrication of titanate nanotubes/iron oxide magnetic composite for the high efficient capture of radionuclides: a case investigation of 109Cd(II)

    International Nuclear Information System (INIS)

    Lei Dai; Jun Zheng; Lijie Wang

    2013-01-01

    In this paper, the capture of radiocadmium (Cd(II)) by adsorption onto the titanate nanotube/iron oxide (TNT/IOM) magnetic composite as a function of contact time, pH, ionic strength, foreign cation and anion ions, humic acid (HA) and fulvic acid (FA) was studied using batch technique. The results indicated that the adsorption of Cd(II) onto the TNT/IOM magnetic composite was dependent on ionic strength at pH 9.0. Outer-sphere surface complexation were the main mechanism of Cd(II) adsorption onto the TNT/IOM magnetic composite at low pH values, whereas the adsorption was mainly dominated via inner-sphere surface complexation at high pH values. The adsorption of Cd(II) onto the TNT/IOM magnetic composite was dependent on foreign cation and anion ions at low pH values, but was independent of foreign cation and anion ions at high pH values. A positive effect of HA/FA on Cd(II) adsorption onto the TNT/IOM magnetic composite was found at low pH values, while a negative effect was observed at high pH values. From the results of Cd(II) removal by the TNT/IOM magnetic composite, the optimum reaction conditions can be obtained for the maximum removal of Cd(II) from water. It is clear that the best pH values of the system to remove Cd(II) from solution by using the TNT/IOM magnetic composite are 7.0-8.0. Considering the low cost and effective disposal of Cd(II)-contaminated wastewaters, the best condition for Cd(II) capture by the TNT/IOM magnetic composite is at room temperature and solid content of 0.5 g L -1 . These results are quite important for estimating and optimizing the removal of Cd(II) and related metal ions by the TNT-based magnetic composite. (author)

  18. Determination of type A trichothecenes in coix seed by magnetic solid-phase extraction based on magnetic multi-walled carbon nanotubes coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dong, Maofeng; Si, Wenshuai; Wang, Weimin; Bai, Bing; Nie, Dongxia; Song, Weiguo; Zhao, Zhihui; Guo, Yirong; Han, Zheng

    2016-09-01

    Magnetic solid-phase extraction (m-SPE) is a promising sample preparation approach due to its convenience, speed, and simplicity. For the first time, a rapid and reliable m-SPE approach using magnetic multi-walled carbon nanotubes (m-MWCNTs) as the adsorbent was proposed for purification of type A trichothecenes including T-2 toxins (T2), HT-2 toxins (HT-2), diacetoxyscirpenol (DAS), and neosolaniol (NEO) in coix seed. The m-MWCNTs were synthesized by assembling the magnetic nanoparticles (Fe3O4) with MWCNTs by sonication through an aggregation wrap mechanism, and characterized by transmission electron microscope. Several key parameters affecting the performance of the procedure were extensively investigated including extraction solutions, desorption solvents, and m-MWCNT amounts. Under the optimal sample preparation conditions followed by analysis with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), high sensitivity (limit of quantification in the range of 0.3-1.5 μg kg(-1)), good linearity (R (2) > 0.99), satisfactory recovery (73.6-90.6 %), and acceptable precision (≤2.5 %) were obtained. The analytical performance of the developed method has also been successfully evaluated in real coix seed samples. Graphical Abstract Flow chart of determination of type A trichothecenes in coix seed by magnetic solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

  19. Magnetic Fusion Energy Technology Fellowship Program: Summary of program activities for calendar year 1985

    International Nuclear Information System (INIS)

    1985-01-01

    This report summarizes the activities of the US Department of Energy (DOE) Magnetic Fusion Energy Technology Fellowship program (MFETF) for the 1985 calendar year. The MFETF program has continued to support the mission of the Office of Fusion Energy (OFE) and its Division of Development and Technology (DDT) by ensuring the availability of appropriately trained engineering manpower needed to implement the OFE/DDT magnetic fusion energy agenda. This program provides training and research opportunities to highly qualified students at DOE-designated academic, private sector, and government magnetic fusion energy institutions. The objectives of the Magnetic Fusion Energy Technology Fellowship program are: (1) to provide support for graduate study, training, and research in magnetic fusion energy technology; (2) to ensure an adequate supply of appropriately trained manpower to implement the nation's magnetic fusion energy agenda; (3) to raise the visibility of careers in magnetic fusion energy technology and to encourage students to pursue such careers; and (4) to make national magnetic fusion energy facilities available for manpower training

  20. Illuminating the future of silicon photonics: optical coupling of carbon nanotubes to microrings

    International Nuclear Information System (INIS)

    Kato, Y K

    2015-01-01

    Advances in carbon nanotube material quality and processing techniques have led to an increased interest in nanotube photonics. In particular, emission in the telecommunication wavelengths makes nanotubes compatible with silicon photonics. Noury et al (2014 Nanotechnology 25 215201) have reported on carbon nanotube photoluminescence coupled to silicon microring resonators, underscoring the advantage of combining carbon nanotube emitters with silicon photonics. Their results open up the possibility of using nanotubes in other waveguide-based devices, taking advantage of well-established technologies. (viewpoint)

  1. Magnetic Refrigeration Technology for High Efficiency Air Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Boeder, A; Zimm, C

    2006-09-30

    Magnetic refrigeration was investigated as an efficient, environmentally friendly, flexible alternative to conventional residential vapor compression central air conditioning systems. Finite element analysis (FEA) models of advanced geometry active magnetic regenerator (AMR) beds were developed to minimize bed size and thus magnet mass by optimizing geometry for fluid flow and heat transfer and other losses. Conventional and magnetocaloric material (MCM) regenerator fabrication and assembly techniques were developed and advanced geometry passive regenerators were built and tested. A subscale engineering prototype (SEP) magnetic air conditioner was designed, constructed and tested. A model of the AMR cycle, combined with knowledge from passive regenerator experiments and FEA results, was used to design the regenerator beds. A 1.5 Tesla permanent magnet assembly was designed using FEA and the bed structure and plenum design was extensively optimized using FEA. The SEP is a flexible magnetic refrigeration platform, with individually instrumented beds and high flow rate and high frequency capability, although the current advanced regenerator geometry beds do not meet performance expectations, probably due to manufacturing and assembly tolerances. A model of the AMR cycle was used to optimize the design of a 3 ton capacity magnetic air conditioner, and the system design was iterated to minimize external parasitic losses such as heat exchanger pressure drop and fan power. The manufacturing cost for the entire air conditioning system was estimated, and while the estimated SEER efficiency is high, the magnetic air conditioning system is not cost competitive as currently configured. The 3 ton study results indicate that there are other applications where magnetic refrigeration is anticipated to have cost advantages over conventional systems, especially applications where magnetic refrigeration, through the use of its aqueous heat transfer fluid, could eliminate intermediate

  2. Synergistic effect of non-covalent interaction in colloidal nematic liquid crystal doped with magnetic functionalized single-walled carbon nanotubes

    Science.gov (United States)

    Dalir, Nima; Javadian, Soheila

    2018-03-01

    Single-walled carbon nanotubes (SWCNTs), CNT@Fe3O4, and Fe3O4 nanocomposites were doped to eutectic uniaxial nematic liquid crystal (NLC's) (E5CN7) to improve physiochemical properties such as phase transition temperature, activation energy (Ea), dielectric anisotropy, and electro-optical properties. The thermal study of nematic phase shows a decrease in the nematic to isotropic phase transition temperature as CNT is doped. However, higher doping concentration of CNTs leads to the further increase in transition temperature. The anchoring effect or π-π interaction plays a key role in N-I phase transition. The functionalization of SWCNTs with Fe3O4 diminishes the CNT aggregation while the magnetic susceptibility is increased. The functionalized CNT doping to NLC's decrease significantly the phase transition temperature compared to doping of non-functionalized CNTs. Attractive interaction between guest and host molecules by magnetic and geometry effect increased the enthalpy and entropy of phase transition in the SWCNT@Fe3O4 sample compared to non-functionalized CNT doped system. Also, the Ea values are decreased as SWCNT@Fe3O4 is doped to pure E5CN7. The difference of N-I phase transition temperature was observed in Fe3O4 and CNT@Fe3O4 compared to SWCNT doped systems. Finally, dielectric anisotropy was increased in the doped system compared to pure NLC.

  3. Application of Laplace transform for the exact effect of a magnetic field on heat transfer of carbon nanotubes-suspended nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Ebaid, Abdelhalim; Al Sharif, Mohammed A. [Tabuk Univ. (Saudi Arabia). Faculty of Science

    2015-10-01

    Since the discovery of the carbon nanotubes (CNTs), there is an increasing interest in their applications in industry and medical fields. Attempts of using such CNTs as drug carriers and in cancer therapy in the presence of a magnetic field are now undertaken because of their direct impacts on increasing the thermal conductivity of base fluids. Two types of CNTs are well known for the researchers, the single-walled CNT (SWCNTs) and the multi-walled CNTs (MWCNTs); however, the subject of which one is more effective in treatment of cancer deserves more investigations. The present article discusses the effect of such types of CNTs on the flow and heat transfer of nanofluids in the presence of a magnetic field. Exact analytical solution for the heat equation has been obtained by using the Laplace transform, where the solution is expressed in terms of a new special function, the generalised incomplete gamma function. The effects of various parameters on the fluid velocity, temperature distribution, and heat transfer rates have been introduced. Details of possible applications of the current results in the treatment of cancer have been also discussed.

  4. Application of Laplace transform for the exact effect of a magnetic field on heat transfer of carbon nanotubes-suspended nanofluids

    International Nuclear Information System (INIS)

    Ebaid, Abdelhalim; Al Sharif, Mohammed A.

    2015-01-01

    Since the discovery of the carbon nanotubes (CNTs), there is an increasing interest in their applications in industry and medical fields. Attempts of using such CNTs as drug carriers and in cancer therapy in the presence of a magnetic field are now undertaken because of their direct impacts on increasing the thermal conductivity of base fluids. Two types of CNTs are well known for the researchers, the single-walled CNT (SWCNTs) and the multi-walled CNTs (MWCNTs); however, the subject of which one is more effective in treatment of cancer deserves more investigations. The present article discusses the effect of such types of CNTs on the flow and heat transfer of nanofluids in the presence of a magnetic field. Exact analytical solution for the heat equation has been obtained by using the Laplace transform, where the solution is expressed in terms of a new special function, the generalised incomplete gamma function. The effects of various parameters on the fluid velocity, temperature distribution, and heat transfer rates have been introduced. Details of possible applications of the current results in the treatment of cancer have been also discussed.

  5. Solid phase extraction of heavy metal ions based on a novel functionalized magnetic multi-walled carbon nanotube composite with the aid of experimental design methodology

    International Nuclear Information System (INIS)

    Taghizadeh, Mohsen; Asgharinezhad, Ali Akbar; Samkhaniany, Noorallah; Tadjarodi, Azadeh; Abbaszadeh, Abolfazl; Pooladi, Mohsen

    2014-01-01

    We report that magnetic multiwalled carbon nanotubes functionalized with 8-aminoquinoline can be applied to the preconcentration of Cd(II), Pb(II) and Ni(II) ions. The parameters affecting preconcentration were optimized by a Box-Behnken design through response surface methodology. Three variables (extraction time, magnetic sorbent amount, and pH value) were selected as the main factors affecting sorption, and four variables (type, volume and concentration of the eluent; elution time) were selected for optimizing elution. Following sorption and elution, the ions were quantified by FAAS. The LODs are 0.09, 0.72, and 1.0 ng mL −1 for Cd(II), Ni(II), and Pb(II) ions, respectively. The relative standard deviations are <5.1 % for five separate batch determinations at 30 ng mL −1 level of Cd(II), Ni(II), and Pb(II) ions. The sorption capacities (in mg g −1 ) of this new sorbent are 201 for Cd(II), 150 for Pb(II), and 172 Ni(II). The composite was successfully applied to the rapid extraction of trace quantities of heavy metal ions in fish, sediment, soil, and water samples. (author)

  6. Nb3Sn accelerator magnet technology R&D at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; DiMarco, J.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; /Fermilab

    2007-06-01

    Accelerator magnets based on Nb{sub 3}Sn superconductor are being developed at Fermilab. Six nearly identical 1-m long dipole models and several mirror configurations were built and tested demonstrating magnet performance parameters and their reproducibility. The technology scale up program has started by building and testing long dipole coils. The results of this work are reported in the paper.

  7. Nb3Sn accelerator magnet technology R and D at Fermilab

    International Nuclear Information System (INIS)

    Zlobin, A.V.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; DiMarco, J.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Fermilab

    2007-01-01

    Accelerator magnets based on Nb 3 Sn superconductor are being developed at Fermilab. Six nearly identical 1-m long dipole models and several mirror configurations were built and tested demonstrating magnet performance parameters and their reproducibility. The technology scale up program has started by building and testing long dipole coils. The results of this work are reported in the paper

  8. A new application and experimental validation of moulding technology for ferrite magnet assisted synchronous reluctance machine

    DEFF Research Database (Denmark)

    Wu, Qian; Lu, Kaiyuan; Rasmussen, Peter Omand

    2016-01-01

    This paper introduces a new application of moulding technology to the installation of ferrite magnet material into the rotor flux barriers of Ferrite Magnet Assisted Synchronous Reluctance Machine (FASynRM). The feasibility of this application with respect to manufacturing process and motor...

  9. Multiscale Modeling with Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A

    2006-02-21

    Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of such materials can range from equilibrium and nonequilibrium Quantum Mechanics, to force-field-based Molecular Mechanics and kinetic Monte Carlo, to Mesoscale simulation of evolving morphology, to Finite-Element computation of physical properties. This brief review illustrates some of the above modeling techniques through a number of recent applications with carbon nanotubes: nano electromechanical sensors (NEMS), chemical sensors, metal-nanotube contacts, and polymer-nanotube composites.

  10. Scaffold-free, label-free and nozzle-free biofabrication technology using magnetic levitational assembly.

    Science.gov (United States)

    Parfenov, Vladislav A; Koudan, Elizaveta V; Bulanova, Elena A; Karalkin, Pavel A; Pereira, Frederico DAS; Norkin, Nikita E; Knyazeva, Alisa D; Gryadunova, Anna A; Petrov, Oleg F; Vasiliev, M M; Myasnikov, Maxim; Chernikov, Valery P; Kasyanov, Vladimir A; Marchenkov, Artem Yu; Brakke, Kenneth A; Khesuani, Yusef D; Demirci, Utkan; Mironov, Vladimir A

    2018-05-31

    Tissue spheroids have been proposed as building blocks in 3D biofabrication. Conventional magnetic force-driven 2D patterning of tissue spheroids requires prior cell labeling by magnetic nanoparticles, meanwhile a label-free approach for 3D magnetic levitational assembly has been introduced. Here we present first-time report on rapid assembly of 3D tissue construct using scaffold-free, nozzle-free and label-free magnetic levitation of tissue spheroids. Chondrospheres of standard size, shape and capable to fusion have been biofabricated from primary sheep chondrocytes using non-adhesive technology. Label-free magnetic levitation was performed using a prototype device equipped with permanent magnets in presence of gadolinium (Gd3+) in culture media, which enables magnetic levitation. Mathematical modeling and computer simulations were used for prediction of magnetic field and kinetics of tissue spheroids assembly into 3D tissue constructs. First, we used polystyrene beads to simulate the assembly of tissue spheroids and to determine the optimal settings for magnetic levitation in presence of Gd3+. Second, we proved the ability of chondrospheres to assemble rapidly into 3D tissue construct in the permanent magnetic field in the presence of Gd3+. Thus, scaffold- and label-free magnetic levitation of tissue spheroids is a promising approach for rapid 3D biofabrication and attractive alternative to label-based magnetic force-driven tissue engineering. . © 2018 IOP Publishing Ltd.

  11. High resolution method for the magnetic axis localization for multipole magnets on the base of the garnet films technology

    International Nuclear Information System (INIS)

    Gertsev, K.F.; Gribkov, V.L.; Liskov, V.A.; Chervonenkis, A.J.

    1992-01-01

    The methods of stretched wires for the localization of the magnetic axis may be inconvenient sometimes in accelerators and colliders of very high energies because of high gradients, large lengths and small apertures. High gradients may deform the wires due to the nonzero magnetic susceptibility and microscopic ferromagnetic particles on their surface. Long wires have large sagittas and small apertures of magnets limit the transversal working domains for the measuring devices. Precision optics magnets possess extreme parameters, in particular, in interaction regions. The magneto-optic (MO) methods of the measurements present some new possibilities for the solution of the above problems. The use of MO films for magnetic field visualization and mapping was proposed and shown that on the basis of Bi-substituted iron garnet films and MO Faraday effect it's possible to obtain the quantitative vector maps of complicated magnetic field structure. Later this was described on a large scale. This method was discussed in terms of its applicability to the magnetic axis localization in quadrupoles of accelerators. In our opinion, the films technology has great advantages as compared with the colloidal solution. In this paper the principles and variants of the films method are presented and further development of the method under discussion is described

  12. A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase.

    Science.gov (United States)

    Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

    2016-10-05

    A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV-vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7-102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Influence of multiwalled carbon nanotube addition on the magnetic and reflection-loss characteristics of Mn–Sn–Ti substituted strontium ferrite nanoparticles

    International Nuclear Information System (INIS)

    Jamalian, Majid; Ghasemi, Ali; Paimozd, Ebrahim

    2014-01-01

    Highlights: • Structural properties of nanocomposites were investigated. • The microwave absorbing characteristics were studied. • The synthesized materials are proper candidates for electromagnetic wave absorber. - Abstract: In this work, Mn–Sn–Ti substituted strontium ferrite (Sr-ferrite:SrM) nanoparticles were attached on the outer surface of varied multi-walled carbon nanotubes volume fraction with the amount of 10, 15, 20, 25 and 30, by employing of the sol–gel method. The phase identification and morphologies of the nanocomposites were characterized by X-ray diffraction and field emission scanning microscopy respectively. The obtained results showed that the single phase SrFe 9.5 (Mn 1.25 Sn 0.625 Ti 0.625 ) O 19 nanoparticles were decorated on MWCNTs can be obtained at 900 °C. Fourier transform infrared revealed that both the stretching and the bending modes are formed in the citrate complex in the ferrite and hydroxyl and carboxyl groups on the external surface of MWCNTs. The Magnetic properties were measured by a vibrating sample magnetometer. It was found that saturation magnetization, remanent magnetization and coercivity decrease by an increase in the MWCNTs content from 10 to 30 vol%. The reflection loss measurement of the prepared absorber which contain the ratio of 70–30 mass% for the nanocomposite to the polyvinyl chloride, done by the vector network analyzer, proved that the prepared nanocomposites have the maximum reflection loss of −28 dB at the frequency of 8.8 GHz for Mn–Ti–Sn substituted strontium ferrite −30 vol% MWCNT nanocomposite with a bandwidth of 4 GHz (RL > −10 dB)

  14. Influence of multiwalled carbon nanotube addition on the magnetic and reflection-loss characteristics of Mn–Sn–Ti substituted strontium ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Jamalian, Majid, E-mail: mjscience@yahoo.com; Ghasemi, Ali; Paimozd, Ebrahim

    2014-08-01

    Highlights: • Structural properties of nanocomposites were investigated. • The microwave absorbing characteristics were studied. • The synthesized materials are proper candidates for electromagnetic wave absorber. - Abstract: In this work, Mn–Sn–Ti substituted strontium ferrite (Sr-ferrite:SrM) nanoparticles were attached on the outer surface of varied multi-walled carbon nanotubes volume fraction with the amount of 10, 15, 20, 25 and 30, by employing of the sol–gel method. The phase identification and morphologies of the nanocomposites were characterized by X-ray diffraction and field emission scanning microscopy respectively. The obtained results showed that the single phase SrFe{sub 9.5} (Mn{sub 1.25}Sn{sub 0.625}Ti{sub 0.625}) O{sub 19} nanoparticles were decorated on MWCNTs can be obtained at 900 °C. Fourier transform infrared revealed that both the stretching and the bending modes are formed in the citrate complex in the ferrite and hydroxyl and carboxyl groups on the external surface of MWCNTs. The Magnetic properties were measured by a vibrating sample magnetometer. It was found that saturation magnetization, remanent magnetization and coercivity decrease by an increase in the MWCNTs content from 10 to 30 vol%. The reflection loss measurement of the prepared absorber which contain the ratio of 70–30 mass% for the nanocomposite to the polyvinyl chloride, done by the vector network analyzer, proved that the prepared nanocomposites have the maximum reflection loss of −28 dB at the frequency of 8.8 GHz for Mn–Ti–Sn substituted strontium ferrite −30 vol% MWCNT nanocomposite with a bandwidth of 4 GHz (RL > −10 dB)

  15. Adsorption of Nile Blue A from Wastewater Using Magnetic Multi-Walled Carbon Nanotubes: Kinetics and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    Mehrnaz Ghoochian

    2016-04-01

    Full Text Available Background: Synthetic dyes are serious pollutants and wide ranges of methods have been employed for their removal from aquatic systems. We studied the adsorption of "Nile blue A" (NBA, an anionic dye, from aqueous solution by oxidized multi-walled carbon nanotubes (MWCNTs. Methods: Scanning electron microscope and Fourier transform infrared spectroscopy were used to characterize function groups produced at MWCNTs surface. Kinetics and adsorption isotherms of NBA, the effect of temperature, pH, contact time and initial dosage of nanotubes on the adsorption capacity were also assessed. The experimental data were analyzed by Langmuir and Freundlich models. Results: Most of the dye was removed in the first 5 min and best adsorption percentage was at pH 7.0. The equilibrium reached at 45 min. The experimental data were analyzed by Langmuir and Freundlich models and the results fitted well with the Freundlich model. The adsorption kinetic data were analyzed using first-order and the pseudo-second order model and the adsorption kinetic data of NBA dye onto MWCNTs fitted the pseudo-second order model. The maximum adsorption capacity was obtained as 169.49 mg g-1. Conclusion: Freundlich model suggested that the adsorption process followed heterogeneous distribution onto MWCNTs and pseudo-second model of adsorption implied that chemical processes controlled the rate-controlling step. Oxidized MWCNTs could be used as an effective adsorbent for the removal of "Nile Blue A" dye. Oxidization of MWCNTs by nitric acid, improves the efficiency of NBA removal due to increases in functional groups and total number of adsorption sites.

  16. Development and Test of LARP Technological Quadrupole (TQC) Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Whitson, G.; Yamada, R.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hannaford, R.; Hafalia, A.R.; Sabbi, G.

    2007-06-01

    In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5 K are presented, including magnet training, current ramp rate studies and magnet quench current. Results of magnetic measurements at helium temperature are also presented.

  17. Development and Test of LARP Technological Quadrupole (TQC) Magnet

    International Nuclear Information System (INIS)

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Whitson, G.; Yamada, R.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hannaford, R.; Hafalia, A.R.; Sabbi, G.

    2007-01-01

    In support of the development of a large-aperture Nb 3 Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90 mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5 K are presented, including magnet training, current ramp rate studies and magnet quench current. Results of magnetic measurements at helium temperature are also presented

  18. Development and test of LARP technological quadrupole (TQC) magnet

    Energy Technology Data Exchange (ETDEWEB)

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.; /Fermilab /LBL, Berkeley

    2006-08-01

    In support of the development of a large-aperture Nb{sub 3}Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90-mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5K are presented, including magnet training, current ramp rate studies and magnet quench current . Results of magnetic measurements at helium temperature are also presented.

  19. Development and test of LARP technological quadrupole (TQC) magnet

    International Nuclear Information System (INIS)

    Feher, S.; Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Nobrega, F.; Novitski, I.

    2006-01-01

    In support of the development of a large-aperture Nb 3 Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90-mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the construction and test of model TQC01. ANSYS calculations of the structure are compared with measurements during construction. Fabrication experience is described and in-process measurements are reported. Test results at 4.5K are presented, including magnet training, current ramp rate studies and magnet quench current . Results of magnetic measurements at helium temperature are also presented

  20. A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Qian; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

    2016-10-05

    A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV–vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7–102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. - Highlights: • A strategy for the magnetic solid-phase extraction of Cu, Zn-SOD based on polymeric ionic liquid has been developed. • The Cu, Zn-SOD remained high specific activity after extraction. • The magnetic adsorbent could be recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples.

  1. A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase

    International Nuclear Information System (INIS)

    Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

    2016-01-01

    A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV–vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7–102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. - Highlights: • A strategy for the magnetic solid-phase extraction of Cu, Zn-SOD based on polymeric ionic liquid has been developed. • The Cu, Zn-SOD remained high specific activity after extraction. • The magnetic adsorbent could be recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples.

  2. Progress in fusion technology in the U.S. magnetic fusion program

    International Nuclear Information System (INIS)

    Dowling, R.J.; Beard, D.S.; Haas, G.M.; Stone, P.M.; George, T.V.

    1987-01-01

    In this paper the authors discuss the major technological achievements that have taken place during the past few years in the U.S. magnetic fusion program which have contributed to the global efforts. The goal has been to establish the scientific and technological base required for fusion energy. To reach this goal the fusion RandD program is focused on four key technical issues: determine the optimum configuration of magnetic confinement systems; determine the properties of burning plasmas; develop materials for fusion systems; and establish the nuclear technology of fusion systems. The objective of the fusion technology efforts has been to develop advanced technologies and provide the necessary support for research of these four issues. This support is provided in a variety of areas such as: high vacuum technology, large magnetic field generation by superconducting and copper coils, high voltage and high current power supplies, electromagnetic wave and particle beam heating systems, plasma fueling, tritium breeding and handling, remote maintenance, energy recovery. The U.S. Fusion Technology Program provides major support or has the primary responsibility in each of the four key technical issues of fusion, as described in the Magnetic Fusion Program Plan of February 1985. This paper has summarized the Technology Program in terms of its activities and progress since the Proceedings of the SOFT Conference in 1984

  3. Tradition and Technology. A Magnet School-Museum Partnership.

    Science.gov (United States)

    Judd, Michael; Judd, Elizabeth

    1996-01-01

    Presents a case study of an educational partnership between an Albuquerque magnet elementary school and the New Mexico Museum of Natural History and Science. Descriptions of the school and museum are provided as well as the program's goals, current activities and products, outcomes, and future directions. The Proyecto Futuro program, a multiyear…

  4. Overview of the Magnetic Fusion Energy Devlopment and Technology Program

    International Nuclear Information System (INIS)

    1978-03-01

    This publication gives a comprehensive introduction to controlled fusion research. Topics covered in the discussion include the following: (1) fusion system engineering and advanced design, (2) plasma engineering, (3) magnetic systems, (4) materials, (5) environment and safety, and (6) alternate energy applications

  5. Effects of electric and magnetic fields on the electronic properties of zigzag carbon and boron nitride nanotubes

    Science.gov (United States)

    Chegel, Raad; Behzad, Somayeh; Ahmadi, Eghbal

    2012-04-01

    We have investigated the electronic properties of zigzag CNTs and BNNTs under the external transverse electric field and axial magnetic field, using tight binding approximation. It was found that after switching on the electric and magnetic fields, the band modification such as distortion of the degeneracy, change in energy dispersion, subband spacing and band gap size reduction occurs. The band gap of zigzag BNNTs decreases linearly with increasing the electric field strength but the band gap variation for CNTs increases first and later decreases (Metallic) or first hold constant and then decreases (semiconductor). For type (II) CNTs, at a weak magnetic field, by increasing the electric field strength, the band gap remains constant first and then decreases and in a stronger magnetic field the band gap reduction becomes parabolic. For type (III) CNTs, in any magnetic field, the band gap increases slowly until reaches a maximum value and then decreases linearly. Unlike to CNTs, the magnetic field has less effects on the BNNTs band gap variation.

  6. Decorating Mg/Fe oxide nanotubes with nitrogen-doped carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cao Yong, E-mail: caoyangel@126.com [Institute of Environment and Municipal Engineering, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Jiao Qingze, E-mail: jiaoqz@bit.edu.cn [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Zhao Yun [School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081 (China); Dong Yingchao [Materials and Surface Science Institute (MSSI), University of Limerick, Limerick (Ireland)

    2011-09-22

    Graphical abstract: Highlights: > Mg/Fe oxide nanotubes arrayed parallel to each other were prepared by an AAO template method. > The Mg/Fe oxide nanotubes decorated with CN{sub x} were realized by CVD of ethylenediamine on the outer surface of oxide nanotubes. > The magnetic properties of Mg/Fe oxide nanotubes were highly improved after being decorated. - Abstract: Mg/Fe oxide nanotubes decorated with nitrogen-doped carbon nanotubes (CN{sub x}) were fabricated by catalytic chemical vapor deposition of ethylenediamine on the outer surface of oxide nanotubes. Mg/Fe oxide nanotubes were prepared using a 3:1 molar precursor solution of Mg(NO{sub 3}){sub 2} and Fe(NO{sub 3}){sub 3} and anodic aluminum oxide as the substrate. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM). The XRD pattern shows that the oxide nanotubes are made up of MgO and Fe{sub 2}O{sub 3}. TEM and SEM observations indicate the oxide nanotubes are arrayed roughly parallel to each other, and the outer surface of oxide nanotubes are decorated with CN{sub x}. XPS results show the nitrogen-doped level in CN{sub x} is about 7.3 at.%. Magnetic measurements with VSM demonstrate the saturated magnetization, remanence and coercivity of oxide nanotubes are obvious improved after being decorated with CN{sub x}.

  7. Synthesis and application of novel ion-imprinted polymer coated magnetic multi-walled carbon nanotubes for selective solid phase extraction of lead(II) ions

    Energy Technology Data Exchange (ETDEWEB)

    Fayazi, Maryam, E-mail: maryam.fayazi@yahoo.com [Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Researchers Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Taher, Mohammad Ali [Department of Chemistry, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Department of Environment, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman (Iran, Islamic Republic of); Mostafavi, Ali [Department of Chemistry, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ghanei-Motlagh, Masoud, E-mail: m.ghaneimotlagh@yahoo.com [Young Researchers Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Department of Chemistry, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2016-03-01

    In this study, novel magnetic ion-imprinted polymer (MIIP) nanoparticles were utilized for the sensitive and selective detection of Pb(II) ions by graphite furnace atomic absorption spectrometry (GFAAS). The Pb(II)-imprinted polymer was synthesized by using 4-vinylpyridine (4VP) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,3,5,6-tetra(2-pyridyl) pyrazine (TPPZ) as the chelating agent and magnetic multi-walled carbon nanotubes (MMWCNTs) as the carrier. The synthesized MIIP materials were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). Various analytical parameters such as extraction and desorption time, eluent type and concentration, pH and sample volume were systematically examined. The selectivity of MIIP sorbent for Pb(II) ions in the presence of some cations was also evaluated. The limit of detection (LOD, 3S{sub b}) and the relative standard deviation (RSD, n = 8, c = 25 ng L{sup −1}) were found to be 2.4 ng L{sup −1} and 5.6%, respectively. The maximum sorption capacity of the MIIP for Pb(II) was found to be 48.1 mg g{sup −1}. Finally, the proposed analytical procedure was successfully applied to monitoring lead in human hair and water samples with satisfactory results for the spiked samples. - Highlights: • A selective and sensitive method based on MSPE-GFAAS was proposed. • The MIIP nanoparticles were characterized using FE-SEM, XRD, VSM and FT-IR techniques. • The synthesized MIIP material is efficient at extracting lead ions. • The method was applied to determine lead ions in several real samples.

  8. Dispersive micro-solid phase extraction of aromatic amines based on an efficient sorbent made from poly(1,8-diaminonaphtalen) and magnetic multiwalled carbon nanotubes composite.

    Science.gov (United States)

    Jalilian, Niloofar; Ebrahimzadeh, Homeira; Asgharinezhad, Ali Akbar

    2017-05-26

    In this work, the extraction of aromatic amines with an efficient magnetic multiwalled carbon nanotubes/Fe 3 O 4 @Poly(1,8-diaminonaphtalen) (MWCNTs/Fe 3 O 4 @PDAN) composite followed by HPLC-DAD was presented. Imprimis, the comparison among different magnetic nanosorbents including Fe 3 O 4 , MWCNTs/Fe 3 O 4 , Fe 3 O 4 @PDAN and MWCNTs/Fe 3 O 4 @PDAN was conducted. The obtained results, exhibited that the MWCNTs/Fe 3 O 4 @PDAN composite has the highest extraction efficiency for target analytes (3-nitroaniline, 4-chloroaniline, 4-bromoaniline and 3,4-dichloroaniline). This sorbent was characterized by Fourier transform infrared spectroscopy, X-ray dispersive spectroscopy, thermogravimetry analysis, scanning electron microscopy, transition electron microscopy, vibrating sample magnetometry and X-ray diffraction. Design of experiment approach was applied to find out the optimal experimental conditions. The optimal extraction conditions were: pH of the sample, 10; sorbent amount, 10mg; sorption time, 15min; salt concentration, 10% w/w; type and volume of the eluent, 0.01molL -1 HCl in acetonitrile, 145μL; elution time; 2min. Under the optimal extraction conditions detection limits and linear dynamic ranges were achieved in the range of 0.1-0.25μgL -1 and 0.25-500μgL -1 , respectively. The percent of extraction recovery and relative standard deviations (n=5) were in the range of 31.2-82.8% and 3.4-5.6%, respectively. Finally, the applicability of the method was successfully confirmed by the extraction and determination of target analytes in various water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Superconducting accelerator magnet technology in the 21st century: A new paradigm on the horizon?

    Science.gov (United States)

    Gourlay, S. A.

    2018-06-01

    Superconducting magnets for accelerators were first suggested in the mid-60's and have since become one of the major components of modern particle colliders. Technological progress has been slow but steady for the last half-century, based primarily on Nb-Ti superconductor. That technology has reached its peak with the Large Hadron Collider (LHC). Despite the superior electromagnetic properties of Nb3Sn and adoption by early magnet pioneers, it is just now coming into use in accelerators though it has not yet reliably achieved fields close to the theoretical limit. The discovery of the High Temperature Superconductors (HTS) in the late '80's created tremendous excitement, but these materials, with tantalizing performance at high fields and temperatures, have not yet been successfully developed into accelerator magnet configurations. Thanks to relatively recent developments in both Bi-2212 and REBCO, and a more focused international effort on magnet development, the situation has changed dramatically. Early optimism has been replaced with a reality that could create a new paradigm in superconducting magnet technology. Using selected examples of magnet technology from the previous century to define the context, this paper will describe the possible innovations using HTS materials as the basis for a new paradigm.

  10. Chitosan magnetic microspheres for technological applications: Preparation and characterization

    International Nuclear Information System (INIS)

    Podzus, P.E.; Daraio, M.E.; Jacobo, S.E.

    2009-01-01

    One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 μm. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

  11. Science and technology of reduced-dimensional magnetic materials

    International Nuclear Information System (INIS)

    Heffner, R.H.; Bishop, A.R.; Hundley, M.F.; Jia, Q.; Neumeier, J.J.; Trugman, S.A.; Thompson, J.D.; Wu, X.D.; Zhang, J.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This work involved the synthesis of single crystal and thin film samples of magnetoresistive manganites (LaMnO 3 doped with Ca and Sr) and the characterization of their electronic transport properties to understand the underlying physical mechanisms responsible for the colossal magnetoresistance (CMR) of these materials. The experimental program was supplemented by a modeling effort that sought to develop microscopic mathematical models of the observed phenomena. The authors succeeded in finding an important relation between the magnetization and resistivity in these materials, which helps to explain the importance of lattice distortions accompanied by clusters of ferromagnetic spins (called spin-lattice polarons) in the CMR phenomena. In addition, they developed rudimentary tunnel junctions of CMR-insulator-CMR multilayers that will lead to possible applications of these materials as magnetic sensors

  12. Synthesis and application of ion imprinting polymer coated magnetic multi-walled carbon nanotubes for selective adsorption of nickel ion

    Science.gov (United States)

    He, Junnan; Shang, Hongzhou; Zhang, Xing; Sun, Xiaoran

    2018-01-01

    A novel nickel ion imprinted polymers (IIPs) based on multi-walled carbon nanotubes (MWCNTs) were synthesized inverse emulsion system, using chitosan(CS) and acrylic acid as the functional monomers, Ni (II) as the template, and N' N-methylene bis-acrylamide as the cross-linker. The chemical structure and morphological feature of the IIPs were characterized by scanning electron microscopy (SEM), Thermogravimetry (TG), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR). The studies indicated that the gel layer was well grafted on the surface of MWCNTs. Studies on the adsorption ability of the IIPs, by atomic absorption spectrophotometry, demonstrated that IIPs possessed excellent adsorption and selective ability towards Ni (II), fitting to pseudo second-order kinetic isotherms and with a maximum capacity of 19.86 mg/g, and selectivity factor of 13.09 and 4.42. The electrochemical performance of ion imprinting carbon paste electrode (CPE/IIPs) was characterized by Cyclic voltammetry (CV). Studies have shown that CPE/IIPs showed excellent electrochemical performance.

  13. Impacts of Interior Permanent Magnet Machine Technology for Electric Vehicles

    Science.gov (United States)

    2012-01-01

    corrosion constraints of magnets  Minimum gear and more direct drive  Regenerative braking and short charging cycle of batteries  Impulse...be found in limited applications such as, antilock braking system (ABS) of the vehicles. Considering the performance enhancement and reliability of... system forms the backbone of modern society. Electricity and its accessibility is one of the major engineering achievements. In order to maintain and

  14. Chirality effect on nearly half-metallic properties in systematic endo-doping of 3d transition metals of narrow carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Malehmir, M.; Khoshnevisan, B., E-mail: b.khosh@kashanu.ac.ir

    2016-10-20

    Spin polarized density functional calculations were employed to study chirality effect on electronic and magnetic properties of 3d transition metals (TMs) endo-doped co-diameter (∼7 Å) narrow (5,5) and (9,0) single walled carbon nanotubes (CNTs). Various magnetizations up to ∼6μ{sub B} was obtained for different 3dTM-CNT systems (recall that the magnetization of fcc structure cobalt is ∼1.6μ{sub B}). In addition nearly half-metallic magnetic behavior has been observed for the most of considered systems. These results would be useful for spintronic and nano-magnetic technology.

  15. Superconductivity application technologies. Superconducting quadrupole magnet and cooling system for KEK B factory

    International Nuclear Information System (INIS)

    Tsuchiya, Kiyosumi; Yamaguchi, Kiyoshi; Sakurabata, Hiroaki; Seido, Masahiro; Matsumoto, Kozo.

    1997-01-01

    At present in National Laboratory for High Energy Physics (KEK), the construction of B factory is in progress. By colliding 8 GeV electrons and 3.5 GeV positrons, this facility generates large amounts of B mesons and anti-B mesons, and performs the elementary particle experiment of high accuracy. It is the collision type accelerator of asymmetric two-ring type comprising 8 GeV and 3.5 GeV rings. In the field of high energy physics, superconductivity technology has been put to practical use. As the objects of superconductivity technology, there are dipole magnet for bending beam, quadrupole magnet for adjusting beam, large solenoid magnet used for detector and so on. Superconducting magnets which are indispensable for high energy, superconducting wire material suitable to accelerators, and the liquid helium cooling system for maintaining superconducting magnets at 4.4 K are reported. The technologies of metallic conductors and making their coils have advanced rapidly, and also cooling technology has advanced, accordingly, superconductivity technology has reached the stage of practical use perfectly. (K.I.)

  16. Technology for SQUID systems for the application in magnetically disturbed environment. Final report

    International Nuclear Information System (INIS)

    Schultze, V.; Fritzsch, L.; Thrum, F.; Stolz, R.; Chwala, A.

    1996-06-01

    International available SQUID systems, as used for example in biomagnetic research, obtain high sensitivities for magnetic fields or magnetic fieldgradients. However, these systems were optimised for operation in magnetically shielded rooms. Goal of this project was to develop SQUIDs suppressing the external noise and therefore are able to operate without external shielding in normal environments. As a consequence, the required Nb/AlO x /Nb technology has also been developed. The resulting planar SQUID gradiometers as produced at the IPHT, reached a suppression of homogeneous fields up to 5 x 10 4 for a magnetic field sensitivity c , project. SQUID gradiometers, produced using YBCO technology, were successfully operated in non shielded eddy current NDE measurements in the lab. (orig.) [de

  17. Technological parameter effect on properties of sintered hard-magnetic type Nd-Fe-B materials

    International Nuclear Information System (INIS)

    Rastegaev, V.S.; Stepanova, G.I.; Gudim, Z.Yu.

    1989-01-01

    The effect of each technological operation on manufacturing hard magnets from Nd-Fe-B alloys on properties of sintered permanent magnets is studied. It is noted that violation of the metting regime can result in burn-up of boron and rare earths, and violation of the grinding mode-formation of nonmagnetic powder fractions, etc. Special attention is paid to material protection against oxidation by introducing passivating additions and creating of particular conditions for alloy sintering and heat treatment

  18. Biodegradable polymer nanocomposites based on natural nanotubes: effect of magnetically modified halloysite on the behaviour of polycaprolactone

    Czech Academy of Sciences Publication Activity Database

    Khunová, V.; Šafařík, Ivo; Škrátek, M.; Kelnar, Ivan; Tomanová, K.

    2016-01-01

    Roč. 51, č. 3 (2016), s. 435-444 ISSN 0009-8558 R&D Projects: GA ČR(CZ) GA13-15255S Institutional support: RVO:60077344 ; RVO:61389013 Keywords : magnetically modified HNTs * biodegradable polymer nanocomposites * polycaprolactone Subject RIV: CD - Macromolecular Chemistry ; JI - Composite Materials (UMCH-V) Impact factor: 1.052, year: 2016

  19. Development and test of a Nb3Sn racetrack magnet using the react and wind technology

    International Nuclear Information System (INIS)

    Ambrosio, G.; Andreev, N.; Barzi, E.; Bauer, P.; Carcagno, R.; Chichili, D.; Ewald, K.; Feher, S.; Imbasciati, L.; Kashikhin, V. V.; Limon, P.; Novitski, I.; Orris, D.; Pischalnikov, Y.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; Yadav, S.; Zlobin, A.V.

    2002-01-01

    Fermilab is involved in the development of a high field accelerator magnet for future hadron colliders using Nb 3 Sn superconductor and the react-and-wind technology. The magnet design is based on single-layer common coils wound simultaneously into a laminated mechanical structure and impregnated with epoxy. In order to develop and optimize the fabrication techniques and to study the conductor performance, a magnet with flat racetrack type coils in a common coil configuration was assembled and tested. The coils were wound in the mechanical structure and in situ impregnated following a procedure that will be used in the single-layer common coil. The magnetic and mechanical design of the racetrack magnet, the fabrication techniques and the test results are presented and discussed in this paper

  20. The overview and history of permanent magnet devices in accelerator technology

    International Nuclear Information System (INIS)

    Kraus, R.H.

    1994-01-01

    This paper looks at the early history of accelerator development with a particular focus on the important discoveries that opened the door for the application of permanent-magnet materials to this area of science. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, that showed magnetic fields could be used to control the transverse envelope of charged-particle beams. Since that time, permanent-magnet materials have found wide application in the modern charged particle accelerator. A brief history of permanent-magnet use in accelerator physics and technology is outlined, some of the general design considerations are presented, and several material properties of concern for particle accelerator applications are discussed

  1. The overview and history of permanent magnet devices in accelerator technology

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.

    1993-01-01

    This paper reviews the early history of accelerator development with a particular focus on the important discoveries that opened the door for the application of permanent-magnet materials to this area of science. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, that showed magnetic fields could be used to control the transverse envelope of charged-particle beams. Since that time, permanent-magnet materials have found wide application in the modern charged particle accelerator. The history of permanent-magnet use in accelerator physics and technology is outlined, general design considerations are presented, and material properties of concern for particle accelerator applications are discussed

  2. The 17th Annual Magnet Technology Conference Hosted By CERN Is Proving That Opposites Attract...

    CERN Multimedia

    2001-01-01

    Hundreds were drawn together by the 17th Magnet Technology Conference, the largest conference devoted to magnets in the world. Thirty-six years ago about 50 physicists and engineers came together at SLAC, Stanford, to have a symposium on magnet technology. Simple as it seemed at the moment, it was the first time that anyone seriously considered building superconducting magnets and was the birth of the Magnet Technology (MT) conference. The conference has occurred every two years since that time and had its most recent incarnation, MT-17, hosted by CERN just last week at the International Conference Centre here in Geneva. With so much innovative work being done with magnets in the LHC and its experiments (ATLAS, CMS, Alice and LHCb), having an MT conference hosted by CERN in Geneva was expected. However, what was not expected was the level of interest with which MT-17 was met. 'We are victims of our own success', says Romeo Perin who was one of the 50 physicists/engineers who attended the Stanford symposium a...

  3. Nb3Sn accelerator magnet technology scale up using cos-theta dipole coils

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, F.; Andreev, N.; Ambrosio, G.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; /Fermilab

    2007-06-01

    Fermilab is working on the development of Nb{sub 3}Sn accelerator magnets using shell-type dipole coils and the wind-and-react method. As a part of the first phase of technology development, Fermilab built and tested six 1 m long dipole model magnets and several dipole mirror configurations. The last three dipoles and two mirrors reached their design fields of 10-11 T. The technology scale up phase has started by building 2 m and 4 m dipole coils and testing them in a mirror configuration in which one of the two coils is replaced by a half-cylinder made of low carbon steel. This approach allows for shorter fabrication times and extensive instrumentation preserving almost the same level of magnetic field and Lorentz forces in the coils as in a complete dipole model magnet. This paper presents details on the 2 m (HFDM07) and 4 m long (HFDM08) Nb{sub 3}Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models.

  4. Nb3Sn accelerator magnet technology scale up using cos-theta dipole coils

    International Nuclear Information System (INIS)

    Nobrega, F.; Andreev, N.; Ambrosio, G.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Fermilab

    2007-01-01

    Fermilab is working on the development of Nb 3 Sn accelerator magnets using shell-type dipole coils and the wind-and-react method. As a part of the first phase of technology development, Fermilab built and tested six 1 m long dipole model magnets and several dipole mirror configurations. The last three dipoles and two mirrors reached their design fields of 10-11 T. The technology scale up phase has started by building 2 m and 4 m dipole coils and testing them in a mirror configuration in which one of the two coils is replaced by a half-cylinder made of low carbon steel. This approach allows for shorter fabrication times and extensive instrumentation preserving almost the same level of magnetic field and Lorentz forces in the coils as in a complete dipole model magnet. This paper presents details on the 2 m (HFDM07) and 4 m long (HFDM08) Nb 3 Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models

  5. Technologies pioneered by LHC. Superconducting magnet and radiation-tolerant tracking detector

    International Nuclear Information System (INIS)

    Yamamoto, Akira; Unno, Yoshinobu

    2007-01-01

    In the LHC project of proton-proton collisions exploring the energy frontier, superconducting magnets and radiation-tolerant tracking detector play fundamental roles as key technologies. The superconducting magnets contribute to bending and focusing particle beam by using high magnetic field created with the NbTi superconductor cooled to the superfluid temperature of He (1.9 K). In order to overcome the unprecedented radiation damage and to capture the particles emerging with high energy and high density, the large area and highly radiation-tolerant silicon semiconductor tracking detector has been developed for the LHC experiment. (author)

  6. Enhanced microwave absorption and magnetic phase transitions of nanoparticles of multiferroic LaFeO3 incorporated in multiwalled carbon nanotubes (MWCNTs)

    International Nuclear Information System (INIS)

    Mitra, A.; Mahapatra, A.S.; Mallick, A.; Chakrabarti, P.K.

    2017-01-01

    Highlights: • Nanoparticles of LaFeO 3 are successfully incorporated in MWCNTs. • Interestingly, phase transitions of LaFeO 3 -MWCNTs are observed in magnetic data. • Superparamagnetic relaxations of LFO in MWCNTs are found at and above ∼298 K. • Microwave absorption of LFO is highly enhanced in the composite of LFO-MWCNTs. - Abstract: Multiferroic nanoparticles of LaFeO 3 (LFO) are prepared by a combination of sono-chemical and sol-gel auto combustion method. The as prepared sample is calcined at 500 °C for 5 h to get the desired crystallographic phase. To enhance the microwave absorption, nanoparticles of LFO are incorporated in the matrix of multi-walled carbon nanotubes (MWCNTs). Crystallographic phases of LFO and LFO-MWCNTs are confirmed by analyzing the X-ray diffractograms (XRD) using Rietveld method. The average size of nanoparticles, crystallographic phase, morphology, and incorporation of LFO nanoparticles in MWCNTs are also obtained by high-resolution transmission electron microscope (HRTEM). Micrographs, nanocrystalline fringe pattern and selected area electron diffraction pattern recorded during HRTEM observations confirmed the formation of the desired nanocomposite phase of LFO-MWCNTs. FTIR and Raman spectroscopy of LFO and LFO-MWCNTs are also recorded at room temperature (RT) which confirm the presence of the individual component in the nanocomposite sample. Hysteresis loops at different temperatures from 300 K down to 5 K, zero field cooled (ZFC) and field cooled (FC) magnetizations (M) as a function of temperature (T) of LFO-MWCNTs are recorded in SQUID magnetometer. Analysis of the observed magnetic data of LFO-MWCNTs suggests the presence of superparamagnetism above ∼298 K and a spin-glass like behavior is found below ∼50 K. The electromagnetic wave absorbing properties in X and K u bands of microwave regions (8–12 GHz and 12–18 GHz) measured by a vector network analyzer (VNA) confirm the significant enhancement of microwave

  7. Enhanced microwave absorption and magnetic phase transitions of nanoparticles of multiferroic LaFeO{sub 3} incorporated in multiwalled carbon nanotubes (MWCNTs)

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, A.; Mahapatra, A.S.; Mallick, A.; Chakrabarti, P.K., E-mail: pabitra_c@hotmail.com

    2017-08-01

    Highlights: • Nanoparticles of LaFeO{sub 3} are successfully incorporated in MWCNTs. • Interestingly, phase transitions of LaFeO{sub 3}-MWCNTs are observed in magnetic data. • Superparamagnetic relaxations of LFO in MWCNTs are found at and above ∼298 K. • Microwave absorption of LFO is highly enhanced in the composite of LFO-MWCNTs. - Abstract: Multiferroic nanoparticles of LaFeO{sub 3} (LFO) are prepared by a combination of sono-chemical and sol-gel auto combustion method. The as prepared sample is calcined at 500 °C for 5 h to get the desired crystallographic phase. To enhance the microwave absorption, nanoparticles of LFO are incorporated in the matrix of multi-walled carbon nanotubes (MWCNTs). Crystallographic phases of LFO and LFO-MWCNTs are confirmed by analyzing the X-ray diffractograms (XRD) using Rietveld method. The average size of nanoparticles, crystallographic phase, morphology, and incorporation of LFO nanoparticles in MWCNTs are also obtained by high-resolution transmission electron microscope (HRTEM). Micrographs, nanocrystalline fringe pattern and selected area electron diffraction pattern recorded during HRTEM observations confirmed the formation of the desired nanocomposite phase of LFO-MWCNTs. FTIR and Raman spectroscopy of LFO and LFO-MWCNTs are also recorded at room temperature (RT) which confirm the presence of the individual component in the nanocomposite sample. Hysteresis loops at different temperatures from 300 K down to 5 K, zero field cooled (ZFC) and field cooled (FC) magnetizations (M) as a function of temperature (T) of LFO-MWCNTs are recorded in SQUID magnetometer. Analysis of the observed magnetic data of LFO-MWCNTs suggests the presence of superparamagnetism above ∼298 K and a spin-glass like behavior is found below ∼50 K. The electromagnetic wave absorbing properties in X and K{sub u} bands of microwave regions (8–12 GHz and 12–18 GHz) measured by a vector network analyzer (VNA) confirm the significant

  8. Sorption and preconcentration of uranium and thorium from aqueous solutions using multi-walled carbon nanotubes decorated with magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zolfonoun, Ehsan; Yousefi, Seyed Reza [NFCRS, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2015-07-01

    The presented study investigates application of MWCNTs-Fe{sub 3}O{sub 4} nanocomposite as an adsorbent for solid phase extraction and preconcentration of uranium and thorium prior to inductively coupled plasma optical emission spectrometry determination. The magnetic MWCNTs with adsorbed analytes can be easily separated from the aqueous solution by using an external magnet without additional centrifugation or filtration of the sample. Due to the high surface area of MWCNTs, satisfactory concentration factor and extraction recovery can be achieved with only 10 mg nanocomposite in 5 min. The effects of pH, sorbent amount, eluent type, chelating reagent concentration, sample volume and time on the recovery of the analytes were investigated. Under the optimum conditions, the detection limits for U(VI) and Th(IV) were 0.44 and 0.27 μg L{sup -1}, respectively.

  9. Development and Test of TQC models, LARP Technological Quadrupole Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Nobrega, F.; Novitski, I.; Orris, D.; Tartaglia, M.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hafalia, A.R.; Sabbi, G.

    2008-06-01

    In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the development and test of TQC01b, the second TQC model, and the experience during construction of TQE02 and TQC02, subsequent models in the series. ANSYS analysis of the mechanical structure, its underlying assumptions, and changes based on experience with TQC01 are presented and discussed. Construction experience, in-process measurements, and modifications to the assembly since TQC01 are described. The test results presented here include magnet strain and quench performance during training of TQC01b, as well as quench studies of current ramp rate dependence.

  10. Development and Test of TQC models, LARP Technological Quadrupole Magnets

    International Nuclear Information System (INIS)

    Bossert, R.C.; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Nobrega, F.; Novitski, I.; Orris, D.; Tartaglia, M.; Zlobin, A.V.; Caspi, S.; Dietderich, D.; Ferracin, P.; Hafalia, A.R.; Sabbi, G.

    2008-01-01

    In support of the development of a large-aperture Nb3Sn superconducting quadrupole for the Large Hadron Collider (LHC) luminosity upgrade, two-layer quadrupole models (TQC and TQS) with 90mm aperture are being constructed at Fermilab and LBNL within the framework of the US LHC Accelerator Research Program (LARP). This paper describes the development and test of TQC01b, the second TQC model, and the experience during construction of TQE02 and TQC02, subsequent models in the series. ANSYS analysis of the mechanical structure, its underlying assumptions, and changes based on experience with TQC01 are presented and discussed. Construction experience, in-process measurements, and modifications to the assembly since TQC01 are described. The test results presented here include magnet strain and quench performance during training of TQC01b, as well as quench studies of current ramp rate dependence

  11. Active magnetic regenerator refrigeration with rotary multi-bed technology

    DEFF Research Database (Denmark)

    Eriksen, Dan

    is a flux conducting iron core which was laminated for electrical and thermal insulation to minimize heat leaks and eddy current losses. Experimental investigations with different configurations of iron and insulation in the core focusing on the impact on temperature span and COP were conducted. AMR...... magnetic regenerator (AMR) prototypes. The starting point is the design and ex- periments with a rotary multi-bed prototype at the Technical University of Denmark. Promising results were obtained with this machine in terms of temperature span and cooling power. However, issues limiting the energy...... the former may be reduced by simple design improvements, the latter is non- trivial and requires detailed geometrical optimization assisted by numerical modeling and improved manufacturing techniques. Finally, possible applications are discussed and a concept of operating the AMR machine in combination...

  12. Development of nuclear magnetic resonance tomography technology - TORM

    International Nuclear Information System (INIS)

    Tannus, A.

    1987-01-01

    The development of hardware and software necessary to implement the Magnetic Resonance Imaging (MRI) techniques is described. The major subjects were the construction of an aquisition and control system which allowed the operation of a pulsed Fourier NMR spectrometer as a NMR Tomograph; further it was oriented the developing of a NMR spectrometer whose parameters could be easily reconfigured by the controlling system. As a result a sofisticated equipment which allows, more than the proposed, working with high resolution spectroscopic techniques and spectroscopy in solids, was obtained. Since the basic techniques employed in NMR and CT Tomographs are well known, a great emphasis was also given on the understanding of the image reconstruction techniques that constitutes today the frontier of research in this area. The results obtained with the system described here are considered good, comparable to the results from commercial units developed in cooperation with imaging groups located in universities abroad. (author) [pt

  13. Monte Carlo study of magnetic nanoparticles adsorbed on halloysite Al2Si2O5(OH) 4 nanotubes

    Science.gov (United States)

    Sotnikov, O. M.; Mazurenko, V. V.; Katanin, A. A.

    2017-12-01

    We study properties of magnetic nanoparticles adsorbed on the halloysite surface. For that a distinct magnetic Hamiltonian with a random distribution of spins on a cylindrical surface was solved by using a nonequilibrium Monte Carlo method. The parameters for our simulations, the anisotropy constant, nanoparticle size distribution, saturated magnetization, and geometrical characteristics of the halloysite template, were taken from recent experiments. We calculate the hysteresis loops and temperature dependence of the zero-field-cooling (ZFC) susceptibility, the maximum of which determines the blocking temperature. It is shown that the dipole-dipole interaction between nanoparticles moderately increases the blocking temperature and weakly increases the coercive force. The obtained hysteresis loops (e.g., the value of the coercive force) for Ni nanoparticles are in reasonable agreement with the experimental data. We also discuss the sensitivity of the hysteresis loops and ZFC susceptibilities to the change in anisotropy and dipole-dipole interaction, as well as the 3 d -shell occupation of the metallic nanoparticles; in particular we predict larger coercive force for Fe than for Ni nanoparticles.

  14. Photodetector based on carbon nanotubes

    Science.gov (United States)

    Pavlov, A.; Kitsyuk, E.; Ryazanov, R.; Timoshenkov, V.; Adamov, Y.

    2015-09-01

    Photodetector based on carbon nanotubes (CNT) was investigated. Sensors were done on quartz and silicon susbtrate. Samples of photodetectors sensors were produced by planar technology. This technology included deposition of first metal layer (Al), lithography for pads formation, etching, and formation of local catalyst area by inverse lithography. Vertically-aligned multi-wall carbon nanotubes were directly synthesized on substrate by PECVD method. I-V analysis and spectrum sensitivity of photodetector were investigated for 0.4 μm - 1.2 μm wavelength. Resistivity of CNT layers over temperature was detected in the range of -20°C to 100°C.

  15. High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

    KAUST Repository

    Bouhrara, M.; Saih, Y.; Wågberg, T.; Goze-Bac, C.; Abou-Hamad, E.

    2011-01-01

    charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites

  16. Development of Laser-Polarized Noble Gas Magnetic Resonance Imaging (MRI) Technology

    Science.gov (United States)

    Walsworth, Ronald L.

    2004-01-01

    We are developing technology for laser-polarized noble gas nuclear magnetic resonance (NMR), with the aim of enabling it as a novel biomedical imaging tool for ground-based and eventually space-based application. This emerging multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI)-e.g., of lung ventilation, perfusion, and gas-exchange. In addition, laser-polarized noble gases (3He and 1BXe) do not require a large magnetic field for sensitive NMR detection, opening the door to practical MRI with novel, open-access magnet designs at very low magnetic fields (and hence in confined spaces). We are pursuing two specific aims in this technology development program. The first aim is to develop an open-access, low-field (less than 0.01 T) instrument for MRI studies of human gas inhalation as a function of subject orientation, and the second aim is to develop functional imaging of the lung using laser-polarized He-3 and Xe-129.

  17. Nanotube phonon waveguide

    Science.gov (United States)

    Chang, Chih-Wei; Zettl, Alexander K.

    2013-10-29

    Disclosed are methods and devices in which certain types of nanotubes (e.g., carbon nanotubes and boron nitride nanotubes conduct heat with high efficiency and are therefore useful in electronic-type devices.

  18. Nb3Sn accelerator magnet technology scale up based on cos-theta coils

    International Nuclear Information System (INIS)

    Nobrega, F.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; Fermilab

    2006-01-01

    After successful testing of a 1 m long dipole mirror magnet and three dipole models based on two-layer Nb 3 Sn coils, Fermilab has started a Nb 3 Sn technology scale-up program using the dipole mirror design and the developed Nb 3 Sn coil fabrication technology based on the wind-and-react method. The scale-up will be performed in several steps starting from a 2 m long coil made of Powder-in-Tube (PIT) strand. This will be followed by 4 m long Nb 3 Sn coils made of PIT and RRP strands that will be fabricated into dipole mirror magnets and tested. This paper presents a summary of Fermilab's wind-and-react short model program. It includes details on the 2 m and 4 m long, 2 layer Nb 3 Sn dipole mirror magnet design, mechanical structure, and fabrication infrastructure

  19. Nb3Sn accelerator magnet technology scale up based on cos-theta coils

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, F.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bossert, R.; Carcagno, R.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Pischalnikov, Yu.; Sylvester, C.; Tartaglia, M.; Turrioni, D.; Yamada, R.; Zlobin, A.V.; /Fermilab

    2006-08-01

    After successful testing of a 1 m long dipole mirror magnet and three dipole models based on two-layer Nb{sub 3}Sn coils, Fermilab has started a Nb{sub 3}Sn technology scale-up program using the dipole mirror design and the developed Nb{sub 3}Sn coil fabrication technology based on the wind-and-react method. The scale-up will be performed in several steps starting from a 2 m long coil made of Powder-in-Tube (PIT) strand. This will be followed by 4 m long Nb{sub 3}Sn coils made of PIT and RRP strands that will be fabricated into dipole mirror magnets and tested. This paper presents a summary of Fermilab's wind-and-react short model program. It includes details on the 2 m and 4 m long, 2 layer Nb{sub 3}Sn dipole mirror magnet design, mechanical structure, and fabrication infrastructure.

  20. Magnetically responsive (nano) composites as perspective materials for environmental technology applications

    Czech Academy of Sciences Publication Activity Database

    Šafařík, Ivo; Šafaříková, Miroslava

    -, č. 0 (2010), s. 85-90 R&D Projects: GA MPO(CZ) 2A-1TP1/094; GA MŠk OC09052 Institutional research plan: CEZ:AV0Z60870520 Keywords : magnetically responsive materials * ( nano )biocomposites * environmental technology Subject RIV: JI - Composite Materials

  1. Spanish Minister of Science and Technology visits the LHC magnet test facility

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister for Science and Technology, Spain, toured the test facility for LHC magnets in building SM18 during his visit to CERN in November. Photos 01, 02: Felix Rodriguez Mateos (right) explains some of a cryomagnet's myriad connections to the Minister.

  2. Spanish Minister of Science and Technology visits the LHC magnet test facility

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister for Science and Technology, Spain, toured the test facility for LHC magnets in building SM18 during his visit to CERN in November. Photo 01: The Minister (left) with M. Cerrada and G. Babé.

  3. The Mossbauer spectra of carbon nanotubes synthesize using ferrite catalyst

    International Nuclear Information System (INIS)

    Zhang Haiyan; Lin Jiapeng; Peng Zuxiong; Zeng Guoxun; Pang Jinshan; Chen Yiming

    2009-01-01

    The ferrite powder with honeycombed structure obtained by chemical combustion was used as catalyst to synthesize multi-walled carbon nanotubes by chemical vapor deposition. The magnetic components and characters of the the carbon nanotubes synthesized were investigated by X-ray diffraction (XRD), Mossbauer spectra and vibrating-sample magnetometer (VSM). The ferric components of the carbon nanotubes samples can be identified by Mossbauer spectra. The Mossbauer spectra of carbon nanotubes sample after purification contains two ferromagnetic sextet components corresponding to α-Fe species and Fe 3 C (cementite) species. While the Mossbauer spectra of the carbon nanotubes sample before purification contains three ferromagnetic sextet components corresponding to α-Fe species, Fe 3 C species and γ-Fe 2 O 3 . The saturation magnetization intensity Ms of carbon nanotubes sample after purification is decreased from 46.61 to 2.94 emu/g, but the coercive force increasd and reached 328Oe.

  4. Technical Training: EMAG-2005 - Electromagnetic Design and Mathematical Optimization Methods in Magnet Technology

    CERN Multimedia

    Monique Duval

    2005-01-01

    CERN Technical Training 2005: Learning for the LHC! CERN Technical Training, in collaboration with the AT-MEL-EM section, is organising a new course series in the framework of the 2005 CERN Technical Training programme: EMAG-2005 - Electromagnetic Design and Mathematical Optimization Methods in Magnet Technology, composed of three-hour lectures in the morning and topical seminars in the afternoon. The EMAG-2005 course series will run at CERN from Monday April 4 until Thursday April 14 (no lectures on Friday 8). The course series, in English, will focus on the foundations of electromagnetism and the design of accelerator magnets, both normal conducting and superconducting, employing analytical and numerical field computations. Examples of the LHC magnet design using the CERN field computation program ROXIE will be presented. However, EMAG-2005 is not a ROXIE user course: it is rather a course for users or potential users of numerical field computation software, and for magnet designers. The course will be o...

  5. Accelerator Magnet Quench Heater Technology and Quality Control Tests for the LHC High Luminosity Upgrade

    CERN Document Server

    AUTHOR|(CDS)2132435; Seifert, Thomas

    The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) foresees the installation of new superconducting Nb$_{3}$Sn magnets. For the protection of these magnets, quench heaters are placed on the magnet coils. The quench heater circuits are chemically etched from a stainless steel foil that is glued onto a flexible Polyimide film, using flexible printed circuit production technology. Approximately 500 quench heaters with a total length of about 3000 m are needed for the HL-LHC magnets. In order to keep the heater circuit electrical resistance in acceptable limits, an approximately 10 µm-thick Cu coating is applied onto the steel foil. The quality of this Cu coating has been found critical in the quench heater production. The work described in this thesis focuses on the characterisation of Cu coatings produced by electrolytic deposition, sputtering and electron beam evaporation. The quality of the Cu coatings from different manufacturers has been assessed for instance by ambient temperature electrica...

  6. COMMERCIALIZATION DEMONSTRATION OF MID-SIZED SUPERCONDUCTING MAGNETIC ENERGY STORAGE TECHNOLOGY FOR ELECTRIC UTILITYAPPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    CHARLES M. WEBER

    2008-06-24

    As an outgrowth of the Technology Reinvestment Program of the 1990’s, an Agreement was formed between BWXT and the DOE to promote the commercialization of Superconducting Magnetic Energy Storage (SMES) technology. Business and marketing studies showed that the performance of electric transmission lines could be improved with this SMES technology by stabilizing the line thereby allowing the reserved stability margin to be used. One main benefit sought was to double the capacity and the amount of energy flow on an existing transmission line by enabling the use of the reserved stability margin, thereby doubling revenue. Also, electrical disturbances, power swings, oscillations, cascading disturbances and brown/black-outs could be mitigated and rendered innocuous; thereby improving power quality and reliability. Additionally, construction of new transmission lines needed for increased capacity could be delayed or perhaps avoided (with significant savings) by enabling the use of the reserved stability margin of the existing lines. Two crucial technical aspects were required; first, a large, powerful, dynamic, economic and reliable superconducting magnet, capable of oscillating power flow was needed; and second, an electrical power interface and control to a transmission line for testing, demonstrating and verifying the benefits and features of the SMES system was needed. A project was formed with the goals of commercializing the technology by demonstrating SMES technology for utility applications and to establish a domestic capability for manufacturing large superconducting magnets for both commercial and defense applications. The magnet had very low AC losses to support the dynamic and oscillating nature of the stabilizing power flow. Moreover, to economically interface to the transmission line, the magnet had the largest operating voltage ever made. The manufacturing of that design was achieved by establishing a factory with newly designed and acquired equipment

  7. Real-time positioning technology in horizontal directional drilling based on magnetic gradient tensor measurement

    Science.gov (United States)

    Deng, Guoqing; Yao, Aiguo

    2017-04-01

    Horizontal directional drilling (HDD) technology has been widely used in Civil Engineering. The dynamic position of the drill bit during construction is one of significant facts determining the accuracy of the trajectory of HDD. A new method now has been proposed to detecting the position of drill bit by measuring the magnetic gradient tensor of the ground solenoid magnetic beacon. Compared with traditional HDD positioning technologies, this new model is much easier to apply with lower request for construction sites and higher positioning efficiency. A direct current (DC) solenoid as a magnetic dipole is placed on ground near the drill bit, and related sensors array which contains four Micro-electromechanical Systems (MEMS ) tri-axial magnetometers, one MEMS tri-axial accelerometer and one MEMS tri-axial gyroscope is set up for measuring the magnetic gradient tensor of the magnetic dipole. The related HDD positioning model has been established and simulation experiments have been carried out to verify the feasibility and reliability of the proposed method. The experiments show that this method has good positioning accuracy in horizontal and vertical direction, and totally avoid the impact of the environmental magnetic field. It can be found that the posture of the magnetic beacon will impact the remote positioning precision within valid positioning range, and the positioning accuracy is higher with longer baseline for limited space in drilling tools. The results prove that the relative error can be limited in 2% by adjusting position of the magnetic beacon, the layers of the enameled coil, the sensitive of magnetometers and the baseline distance. Conclusion can be made that this new method can be applied in HDD positioning with better effect and wider application range than traditional method.

  8. Dephasing and hyperfine interaction in carbon nanotubes double quantum dots

    DEFF Research Database (Denmark)

    Reynoso, Andres Alejandro; Flensberg, Karsten

    2012-01-01

    We study theoretically the return probability experiment, which is used to measure the dephasing time T-2*, in a double quantum dot (DQD) in semiconducting carbon nanotubes with spin-orbit coupling and disorder-induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the C...... with these for DQDs in clean nanotubes, whereas the disorder effect is always relevant when the magnetic field is perpendicular to the nanotube axis....

  9. Magnetic fusion energy technology fellowship: Report on survey of institutional coordinators

    International Nuclear Information System (INIS)

    1993-02-01

    In 1980, the Magnetic Fusion Energy Technology (MFET) Fellowship program was established by the US Department of Energy, Office of Fusion Energy, to encourage outstanding students interested in fusion energy technology to continue their education at a qualified graduate school. The basic objective of the MFET Fellowship program is to ensure an adequate supply of scientists in this field by supporting graduate study, training, and research in magnetic fusion energy technology. The program also supports the broader objective of advancing fusion toward the realization of commercially viable energy systems through the research by MFET fellows. The MFET Fellowship program is administered by the Science/Engineering Education Division of Oak Ridge Institute for Science and Education. Guidance for program administration is provided by an academic advisory committee

  10. A magnetic levitation rotating plate model based on high-Tc superconducting technology

    Science.gov (United States)

    Zheng, Jun; Li, Jipeng; Sun, Ruixue; Qian, Nan; Deng, Zigang

    2017-09-01

    With the wide requirements of the training aids and display models of science, technology and even industrial products for the public like schools, museums and pleasure grounds, a simple-structure and long-term stable-levitation technology is needed for these exhibitions. Opportunely, high temperature superconducting (HTS) technology using bulk superconductors indeed has prominent advantages on magnetic levitation and suspension for its self-stable characteristic in an applied magnetic field without any external power or control. This paper explores the feasibility of designing a rotatable magnetic levitation (maglev) plate model with HTS bulks placed beneath a permanent magnet (PM) plate. The model is featured with HTS bulks together with their essential cryogenic equipment above and PMs below, therefore it eliminates the unclear visual effects by spray due to the low temperature coolant such as liquid nitrogen (LN2) and additional levitation weight of the cryogenic equipment. Besides that, a matched LN2 automation filling system is adopted to help achieving a long-term working state of the rotatable maglev plate. The key low-temperature working condition for HTS bulks is maintained by repeatedly opening a solenoid valve and automatically filling LN2 under the monitoring of a temperature sensor inside the cryostat. With the support of the cryogenic devices, the HTS maglev system can meet all requirements of the levitating display model for exhibitions, and may enlighten the research work on HTS maglev applications.

  11. A novel redox-sensitive system based on single-walled carbon nanotubes for chemo-photothermal therapy and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Hou L

    2016-02-01

    Full Text Available Lin Hou,1,2 Xiaomin Yang,1 Junxiao Ren,1 Yongchao Wang,1 Huijuan Zhang,1 Qianhua Feng,1 Yuyang Shi,1 Xiaoning Shan,1 Yujie Yuan,1 Zhenzhong Zhang1,21School of Pharmaceutical Sciences, Zhengzhou University, Henan Province, Zhengzhou, People’s Republic of China; 2Collaborative Innovation Center of New Drug Research and Safety Evaluation, Henan Province, Zhengzhou, People’s Republic of ChinaAbstract: Recently, nanomaterials with multiple functions, such as drug carrier, magnetic resonance imaging (MRI and optical imaging, and photothermal therapy, have become more and more popular in cancer research. In this work, a novel redox-sensitive system constructed from hyaluronic acid (HA, single-walled carbon nanotubes (SWCNTs, doxorubicin (DOX, and gadolinium (Gd was successfully developed. Herein, HA-modified SWCNTs (SWCNTs-HA was first synthesized, and then DOX was conjugated with HA by disulfide bond (SWCNTs-HA-ss-DOX. Finally, MRI contrast agents, Gd3+-ion loading occurred through the sidewall defects of SWCNTs, whose cytotoxicity could be sequestered within the SWCNTs. In vitro release of DOX showed that this system accomplished much faster drug release under reducing condition. Confocal microscopy analysis confirmed that Gd/SWCNTs-HA-ss-DOX were capable of simultaneously delivering DOX and SWCNTs into Michigan Cancer Foundation-7 cells via HA receptor-mediated endocytosis followed by rapid transport of cargoes into the cytosol. Enhanced cytotoxicity of Gd/SWCNTs-HA-ss-DOX further proved that the sensitive system was more potent for intracellular drug delivery as compared with the insensitive control. Meanwhile, tumor cell killing potency was improved when Gd/SWCNTs-HA-ss-DOX were combined with near-infrared irradiation, with IC50 of 0.61 µg/mL at 48 hours. In vivo investigation demonstrated that Gd/SWCNTs-HA-ss-DOX could effectively accumulate in tumor sites and possessed the greatest synergistic antitumor efficacy, especially under the 808 nm

  12. Scalable Solution Processing of Pristine Carbon Nanotubes for Self-Assembled, Tunable Materials with Direct Application to Space Technologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Current material technologies limit space exploration and vehicle performance due to often unnecessary mass increase from copper wiring or heavy structural...

  13. Magnetic fusion energy materials technology program annual progress report for period ending June 30, 1977

    International Nuclear Information System (INIS)

    Scott, J.L.

    1977-09-01

    The objectives of the Magnetic Fusion Energy (MFE) Materials Technology Program, which is described in this report, are to continue to solve the materials problems of the Fusion Energy Division of ORNL and to meet needs of the national MFE program, directed by the ERDA Division of Magnetic Fusion Energy (DMFE). This work is a continuation of the program described in previous annual progress reports. The principal areas of work include radiation effects, compatibility studies, materials studies related to the plasma-materials interaction, materials engineering, radiation behavior of superconducting magnet insulation, and mechanical properties of superconducting composites. The level of effort and schedules are consistent with Logic II of the DMFE Program Plan

  14. Carbon nanotube composite materials

    Science.gov (United States)

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  15. A historical overview of magnetic resonance imaging, focusing on technological innovations.

    Science.gov (United States)

    Ai, Tao; Morelli, John N; Hu, Xuemei; Hao, Dapeng; Goerner, Frank L; Ager, Bryan; Runge, Val M

    2012-12-01

    Magnetic resonance imaging (MRI) has now been used clinically for more than 30 years. Today, MRI serves as the primary diagnostic modality for many clinical problems. In this article, historical developments in the field of MRI will be discussed with a focus on technological innovations. Topics include the initial discoveries in nuclear magnetic resonance that allowed for the advent of MRI as well as the development of whole-body, high field strength, and open MRI systems. Dedicated imaging coils, basic pulse sequences, contrast-enhanced, and functional imaging techniques will also be discussed in a historical context. This article describes important technological innovations in the field of MRI, together with their clinical applicability today, providing critical insights into future developments.

  16. Design and Fabrication of a Miniaturized GMI Magnetic Sensor Based on Amorphous Wire by MEMS Technology

    Directory of Open Access Journals (Sweden)

    Jiawen Chen

    2018-03-01

    Full Text Available A miniaturized Co-based amorphous wire GMI (Giant magneto-impedance magnetic sensor was designed and fabricated in this paper. The Co-based amorphous wire was used as the sense element due to its high sensitivity to the magnetic field. A three-dimensional micro coil surrounding the Co-based amorphous wire was fabricated by MEMS (Micro-Electro-Mechanical System technology, which was used to extract the electrical signal. The three-dimensional micro pick-up coil was designed and simulated with HFSS (High Frequency Structure Simulator software to determine the key parameters. Surface micro machining MEMS (Micro-Electro-Mechanical System technology was employed to fabricate the three-dimensional coil. The size of the developed amorphous wire magnetic sensor is 5.6 × 1.5 × 1.1 mm3. Helmholtz coil was used to characterize the performance of the device. The test results of the sensor sample show that the voltage change is 130 mV/Oe and the linearity error is 4.83% in the range of 0~45,000 nT. The results indicate that the developed miniaturized magnetic sensor has high sensitivity. By testing the electrical resistance of the samples, the results also showed high uniformity of each device.

  17. Workshop on CEBAF [Continuous Electron Beam Accelerator Facility] spectrometer magnet design and technology: Proceedings

    International Nuclear Information System (INIS)

    1986-09-01

    The planned experimental program at CEBAF includes high-resolution, large acceptance spectrometers and a large toroidal magnetic, detector. In order to take full advantage of the high quality beam characteristics, the performances required will make these devices quite unique instruments compared to existing facilities in the same energy range. Preliminary designs have shown that such performances can be reached, but key questions concerning design concepts and most appropriate and cost-effective technologies had to be answered before going further with the designs. It was the purpose of the Workshop on CEBAF Spectrometer Magnet Design and Technology, organized by the CEBAF Research and Engineering Divisions, to provide the most complete information about the state-of-the-art tools and techniques in magnet design and construction and to discuss the ones most appropriate to the CEBAF spectrometers. In addition, it is expected that this Workshop will be the staring point for further interactions and collaborations between international magnet experts and the CEBAF staff, during the whole process of designing and building the spectrometers

  18. An Overview of the Thermal Calculation and the Cooling Technology for Active Magnetic Bearing

    Science.gov (United States)

    Zhang, Li; Yu, Meiyun; Luo, Yanyan; Liu, Jun; Ren, Yafeng

    2017-10-01

    The cooling process of AMB is that the energy loss is sent out to the outside world when the system is operating. The energy loss transfers to the surrounding medium in the form of heat, which leads to raise the temperature of system components and influences the performance of the system. So it is necessary to study the internal loss of the magnetic bearing system and thermal calculation method. Three kinds of thermal calculation methods are compared, which is important for the design and calculation of cooling. At the same time, the cooling way, the cooling method, and the cooling system is summarized on the basis of cooling technology of active magnetic bearing, and the design method of the cooling system is studied. But for the active magnetic bearing system, when designing the cooling system, heat dissipation of the motor can not be ignored. It is important not only for the performance of the active magnetic bearing system and stable operation, and but also for the improvement of the cooling technology.

  19. The technology and science of steady-state operation in magnetically confined plasmas

    International Nuclear Information System (INIS)

    Becoulet, A; Hoang, G T

    2008-01-01

    The steady-state operation of magnetically confined fusion plasmas is considered as one of the 'grand challenges' of future decades, if not the ultimate goal of the research and development activities towards a new source of energy. Reaching such a goal requires the high-level integration of both science and technology aspects of magnetic fusion into self-consistent plasma regimes in fusion-grade devices. On the physics side, the first constraint addresses the magnetic confinement itself which must be made persistent. This means to either rely on intrinsically steady-state configurations, like the stellarator one, or turn the inductively driven tokamak configuration into a fully non-inductive one, through a mix of additional current sources. The low efficiency of the external current drive methods and the necessity to minimize the re-circulating power claim for a current mix strongly weighted by the internal 'pressure driven' bootstrap current, itself strongly sensitive to the heat and particle transport properties of the plasma. A virtuous circle may form as the heat and particle transport properties are themselves sensitive to the current profile conditions. Note that several other factors, e.g. plasma rotation profile, magneto-hydro-dynamics activity, also influence the equilibrium state. In the present tokamak devices, several examples of such 'advanced tokamak' physics research demonstrate the feasibility of steady-state regimes, though with a number of open questions still under investigation. The modelling activity also progresses quite fast in this domain and supports understanding and extrapolation. This high level of physics sophistication of the plasma scenario however needs to be combined with steady-state technological constraints. The technology constraints for steady-state operation are basically twofold: the specific technologies required to reach the steady-state plasma conditions and the generic technologies linked to the long pulse operation of a

  20. Influence of science and technology magnet middle schools on students' motivation and achievement in science

    Science.gov (United States)

    Allen, David

    Some informal discussions among educators regarding motivation of students and academic performance have included the topic of magnet schools. The premise is that a focused theme, such as an aspect of science, positively affects student motivation and academic achievement. However, there is limited research involving magnet schools and their influence on student motivation and academic performance. This study provides empirical data for the discussion about magnet schools influence on motivation and academic ability. This study utilized path analysis in a structural equation modeling framework to simultaneously investigate the relationships between demographic exogenous independent variables, the independent variable of attending a science or technology magnet middle school, and the dependent variables of motivation to learn science and academic achievement in science. Due to the categorical nature of the variables, Bayesian statistical analysis was used to calculate the path coefficients and the standardized effects for each relationship in the model. The coefficients of determination were calculated to determine the amount of variance each path explained. Only five of 21 paths had statistical significance. Only one of the five statistically significant paths (Attended Magnet School to Motivation to Learn Science) explained a noteworthy amount (45.8%) of the variance.

  1. Studies of magnetic properties of permalloy (Fe-30%Ni) prepared by SLM technology

    International Nuclear Information System (INIS)

    Zhang Baicheng; Fenineche, Nour-Eddine; Zhu Lin; Liao Hanlin; Coddet, Christian

    2012-01-01

    In the present study, a high permeability induction Fe-30%Ni alloy cubic bulk was prepared by the selective laser melting process. In order to reveal the microstructure effect on soft magnetic properties, the microstructure and magnetic properties of the Fe-30%Ni alloy were carefully investigated by scanning electron microscopy, X-ray diffraction and hysteresis measurements. The bcc-Fe (Ni) phase formation is identified by X-ray diffraction. Meanwhile, it was found that low bcc lattice parameter and high grain size could be obtained when high laser scanning velocity and low laser power were used. Moreover, the lowest value of coercivity is 88 A/m, and the highest value of saturation magnetization is 565 Am 2 /kg, which can be obtained at a low laser scanning velocity of 0.4 m/s and high laser power input at 110 W. - Highlights: → Proper Fe-30%Ni alloy (permalloy) using selective laser melting technology. → Microstructure of Fe-30%Ni alloy exhibits fine cellular structure of approximately 100 nm. → Magnetic properties can be controlled by laser parameter. → Lowest coercivity is 88 A/m and highest saturation magnetization is 565 Am 2 /kg.

  2. Functionalization of carbon nanotubes with silver clusters

    International Nuclear Information System (INIS)

    Cveticanin, Jelena; Krkljes, Aleksandra; Kacarevic-Popovic, Zorica; Mitric, Miodrag; Rakocevic, Zlatko; Trpkov, Djordje; Neskovic, Olivera

    2010-01-01

    In this paper, an advanced method of one-step functionalization of single and multi walled carbon nanotubes (SWCNTs and MWCNTs) using γ-irradiation was described. Two synthesis procedures, related with different reduction species, were employed. For the first time, poly(vinyl alcohol) PVA is successfully utilized as a source to reduce silver (Ag) metal ions without having any additional reducing agents to obtain Ag nanoparticles on CNTs. The decoration of carbon nanotubes with Ag nanoparticles takes place through anchoring of (PVA) on nanotube's surface. Optical properties of as-prepared samples and mechanism responsible for the functionalization of carbon nanotubes were investigated using UV-vis and FTIR spectroscopy, respectively. Decorated carbon nanotubes were visualized using microscopic techniques: transmission electron microscopy and scanning tunneling microscopy. Also, the presence of Ag on the nanotubes was confirmed using energy dispersive X-ray spectroscopy. This simple and effective method of making a carbon nanotube type of composites is of interest not only for an application in various areas of technology and biology, but for investigation of the potential of radiation technology for nanoengineering of materials.

  3. Positioning and aligning CNTs by external magnetic field to assist localised epoxy cure

    Directory of Open Access Journals (Sweden)

    Ariu G.

    2016-01-01

    Full Text Available This work focuses on the generation of conductive networks through the localised alignment of nano fillers, such as multi-walled carbon nanotubes (MWCNTs. The feasibility of alignment and positioning of functionalised MWCNTs by external DC magnetic fields was investigated. The aim of this manipulation is to enhance resin curing through AC induction heating due to hysteresis losses from the nanotubes. Experimental analyses focused on in-depth assessment of the nanotube functionalisation, processing and characterisation of magnetic, rheological and cure kinetics properties of the MWCNT solution. The study has shown that an external magnetic field has great potential for positioning and alignment of CNTs. The study demonstrated potential for creating well-ordered architectures with an unprecedented level of control of network geometry. Magnetic characterisation indicated cobalt-plated nanotubes to be the most suitable candidate for magnetic alignment due to their high magnetic sensitivity. Epoxy/metal-plated CNT nanocomposite systems were validated by thermal analysis as induction heating mediums. The curing process could therefore be optimised by the use of dielectric resins. This study offers a first step towards the proof of concept of this technique as a novel repair technology.

  4. Positioning and aligning CNTs by external magnetic field to assist localised epoxy cure

    Science.gov (United States)

    Ariu, G.; Hamerton, I.; Ivanov, D.

    2016-01-01

    This work focuses on the generation of conductive networks through the localised alignment of nano fillers, such as multi-walled carbon nanotubes (MWCNTs). The feasibility of alignment and positioning of functionalised MWCNTs by external DC magnetic fields was investigated. The aim of this manipulation is to enhance resin curing through AC induction heating due to hysteresis losses from the nanotubes. Experimental analyses focused on in-depth assessment of the nanotube functionalisation, processing and characterisation of magnetic, rheological and cure kinetics properties of the MWCNT solution. The study has shown that an external magnetic field has great potential for positioning and alignment of CNTs. The study demonstrated potential for creating well-ordered architectures with an unprecedented level of control of network geometry. Magnetic characterisation indicated cobalt-plated nanotubes to be the most suitable candidate for magnetic alignment due to their high magnetic sensitivity. Epoxy/metal-plated CNT nanocomposite systems were validated by thermal analysis as induction heating mediums. The curing process could therefore be optimised by the use of dielectric resins. This study offers a first step towards the proof of concept of this technique as a novel repair technology.

  5. Self-inductance of chiral conducting nanotubes

    International Nuclear Information System (INIS)

    Miyamoto, Yoshiyuki; Rubio, Angel; Louie, Steven G.; Cohen, Marvin L.

    1998-01-01

    Chiral conductivity in nanotubes has recently been predicted theoretically. The realization and application of chiral conducting nanotubes can be of great interest from both fundamental and technological viewpoints. These chiral currents, if they are realized, can be detected by measuring the self-inductance. We have treated Maxwell's equations for chiral conducting nanotubes (nanocoils) and find that the self-inductance and the resistivity of nanocoils should depend on the frequency of the alternating current even when the capacitance of the nanocoils is not taken into account. This is in contrast to elementary treatment of ordinary coils. This fact is useful to distinguish nanocoils by electrical measurements

  6. The suspended magnetic separator with large blocks from NdFeB magnets and its long term technological tests

    Czech Academy of Sciences Publication Activity Database

    Žežulka, Václav; Straka, Pavel

    2011-01-01

    Roč. 8, č. 1 (2011), s. 89-97 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30460519 Keywords : magnetic separation * magnetic separators * magnetic circuits Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/01_11/8_Zezulka.pdf

  7. The permanent NdFeB magnets in the circuits for magnetic filters and the first technological tests

    Czech Academy of Sciences Publication Activity Database

    Žežulka, Václav; Straka, Pavel; Mucha, Pavel

    2005-01-01

    Roč. 78, - (2005), s. 31-39 ISSN 0301-7516 R&D Projects: GA AV ČR IBS3046004 Institutional research plan: CEZ:AV0Z30460519 Keywords : magnetic circuit * magnetic filter * rare earth magnets ( NdFeB ) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.965, year: 2005

  8. Emerging boom in nano magnetic particle incorporated high-Tc superconducting materials and technologies - A South African perspective

    CSIR Research Space (South Africa)

    Srinivasu, VV

    2009-01-01

    Full Text Available With a strategy to establish and embrace the emerging nano particle incorporated superconductivity technology (based on the HTS materials and nano magnetic particles) in South Africa, the author has initiated the following research activity in South...

  9. Adoption and diffusion of a new imaging technology: a magnetic resonance imaging prospective

    International Nuclear Information System (INIS)

    Hillman, B.J.; Winkler, J.D.; Phelps, C.E.; Aroesty, J.; Williams, A.P.

    1984-01-01

    Adoption of magnetic resonance imaging (MRI) by individual purchasers and by the health care system will be influenced by many factors. A framework for considering these influences is offered, incorporating them into four major considerations: (1) MRI and its attributes - the technology, its safety and efficacy, and the benefits of acquisition; (2) communication channels - commercial and professional; (3) time for consideration of adoption and experiential testing; and (4) the medical system, including potential acquirers, health planning, and reimbursement. Factors that should most strongly motivate early adoption are the potential of the technology for providing new and useful clinical information and the competitive and economic benefits that early acquirers might enjoy. Important discouragements include the possibility of early obsolescence and that MRI represents an economic risk under diagnostic-related-group reimbursement. The less risky approach for most practices is to delay acquisition of MRI pending further experience with the technology and the changing reimbursement climate

  10. Implications for School Leaders of the Impact of Math, Science, and Technology Magnet Programs on Middle School Student Achievement

    Science.gov (United States)

    Hinojosa, Lupita

    2012-01-01

    Although many national studies have been conducted on the effectiveness of magnet programs, there is limited research involving math, science, and technology magnet schools and their influence on student academic performance, especially at the middle school level. The purpose of this study was to determine whether a statistical difference existed…

  11. Performance of new 400-MHz HTS power-driven magnet NMR technology on typical pharmaceutical API, cinacalcet HCl.

    Science.gov (United States)

    Silva Elipe, Maria Victoria; Donovan, Neil; Krull, Robert; Pooke, Donald; Colson, Kimberly L

    2018-04-17

    After years towards higher field strength magnets, nuclear magnetic resonance (NMR) technology in commercial instruments in the past decade has expanded at low and high magnetic fields to take advantage of new opportunities. At lower field strengths, permanent magnets are well established, whereas for midrange and high field, developments utilize superconducting magnets cooled with cryogenic liquids. Recently, the desire to locate NMR spectrometers in nontypical NMR laboratories has created interest in the development of cryogen-free magnets. These magnets require no cryogenic maintenance, eliminating routine filling and large cryogen dewars in the facility. Risks of spontaneous quenches and safety concerns when working with cryogenic liquids are eliminated. The highest field commercially available cryogen-free NMR magnet previously reported was at 4.7 T in 2013. Here we tested a prototype cryogen-free 9.4-T power-driven high-temperature-superconducting (HTS) magnet mated to commercial NMR spectrometer electronics. We chose cinacalcet HCl, a typical active pharmaceutical ingredient, to evaluate its performance towards structure elucidation. Satisfactory standard 1D and 2D homonuclear and heteronuclear NMR results were obtained and compared with those from a standard 9.4-T cryogenically cooled superconducting NMR instrument. The results were similar between both systems with minor differences. Further comparison with different shims and probes in the HTS magnet system confirmed that the magnet homogeneity profile could be matched with commercially available NMR equipment for optimal results. We conclude that HTS magnet technology works well providing results comparable with those of standard instruments, leading us to investigate additional applications for this magnet technology outside a traditional NMR facility. Copyright © 2018 John Wiley & Sons, Ltd.

  12. Magnets

    International Nuclear Information System (INIS)

    Young, I.R.

    1984-01-01

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

  13. Technology of mirror machines: LLL facilities for magnetic mirror fusion experiments

    International Nuclear Information System (INIS)

    Batzer, T.H.

    1977-01-01

    Significant progress in plasma confinement and temperature has been achieved in the 2XIIB facility at Livermore. These encouraging results, and their theoretical corroboration, have provided a firm basis for the design of a new generation of magnetic mirror experiments, adding support to the mirror concept of a fusion reactor. Two new mirror experiments have been proposed to succeed the currently operating 2XIIB facility. The first of these called TMX (Tandem Mirror Experiment) has been approved and is currently under construction. TMX is designed to utilize the intrinsic positive plasma potential of two strong, and relatively small, minimum B mirror cells to enhance the confinement of a much larger, magnetically weaker, centrally-located mirror cell. The second facility, MFTF (Mirror Fusion Test Facility), is currently in preliminary design with line item approval anticipated for FY 78. MFTF is designed primarily to exploit the experimental and theoretical results derived from 2XIIB. Beyond that, MFTF will develop the technology for the transition from the present small mirror experiments to large steady-state devices such as the mirror FERF/FTR. The sheer magnitude of the plasma volume, magnetic field, neutral beam power, and vacuum pumping capacity, particularly in the case of MFTF, has placed new and exciting demands on engineering technology. An engineering overview of MFTF, TMX, and associated MFE activities at Livermore will be presented

  14. TECHNOLOGICAL AND ECOLOGICAL SAFETY IN ASPECT OF CHEMICAL PROPERTIES OF RECYCLED NEODYMIUM MAGNETS - ELECTRIC MO-TORS AND HARD DISK

    Directory of Open Access Journals (Sweden)

    Katarzyna Kapustka

    2018-01-01

    Full Text Available Neodymium magnets currently dominate the magnet market due to their superior magnetic proper-ties with maximum volume minimization. In this paper, the results of X-ray analysis for two types of magnetic powder obtained from the recovered magnets traditionally used in electric motors and hard disk have been presented. The NdFeB magnets are composed of 25-35 wt. % rare earth elements (RE and the rest being transition metals (mainly Fe.. RE, other than Nd, such Dy, Pr, Tb and Gd or exogen elements, other than Fe, such as Al, Co, Ga, Nb, Si, Cu and Zr can also be present as minor admixtures. This paper brings an opportunity to introduce the hard magnets recycling technology on an industrial scale.

  15. Test of piezo-ceramic motor technology in ITER relevant high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Monti, Chiara, E-mail: chiara.monti@enea.it [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Besi Vetrella, Ugo; Mugnaini, Giampiero; Neri, Carlo; Rossi, Paolo; Viola, Rosario [Associazione EURATOM-ENEA sulla Fusione, via Enrico Fermi 45, 00044 Frascati, Rome (Italy); Dubus, Gregory; Damiani, Carlo [Fusion for Energy, c/ Josep Pla, 2 Torres Diagonal Litoral, 08019 Barcelona (Spain)

    2014-10-15

    In the framework of a Fusion for Energy (F4E) grant, a test campaign started in 2012 in order to assess the performance of the in-vessel viewing system (IVVS) probe concept and to verify its compatibility when exposed to ITER typical working conditions. ENEA laboratories went through with several tests simulating high magnetic fields, high temperature, high vacuum, gamma radiation and neutron radiation. A customized motor has been adopted to study the performances of ultrasonic piezo motors technology in high magnetic field conditions. This paper reports on the testing activity performed on the motor in a multi Tesla magnetic field. The job was carried out in a test facility of ENEA laboratories able to achieve 14 T. A maximum field of 10 T, fully compliant with ITER requirements (8 T), was applied. A specific mechanical assembly has been designed and manufactured to hold the motor in the region with high homogeneity of the field. Results obtained so far indicate that the motor is compatible with high magnetic fields, and are presented in the paper.

  16. Experimental Design of Electrocoagulation and Magnetic Technology for Enhancing Suspended Solids Removal from Synthetic Wastewater

    Directory of Open Access Journals (Sweden)

    Moh Faiqun Ni'am

    2014-10-01

    Full Text Available Design of experiments (DOE is one of the statistical method that is used as a tool to enhance and improve experimental quality. The changes to the variables of a process or system is supposed to give the optimal result (response and quite satisfactory. Experimental design can defined as a test or series of test series by varying the input variables (factors of a process that can known to cause changes in output (response. This paper presents the results of experimental design of wastewater treatment by electrocoagulation (EC technique. A combined magnet and electrocoagulation (EC technology were designed to increase settling velocity and to enhance suspended solid removal efficiencies from wastewater samples. In this experiment, a synthetic wastewater samples were prepared by mixing 700 mg of the milk powder in one litre of water and treated by using an acidic buffer solution. The monopolar iron (Fe plate anodes and cathodes were employed as electrodes. Direct current was varied in a range of between 0.5 and 1.1 A, and flowrate in a range of between 1.00 to 3.50 mL/s. One permanent magnets namely AlNiCo with a magnetic strength of 0.16T was used in this experiment. The results show that the magnetic field and the flowrate have major influences on suspended solids removal. The efficiency removals of suspended solids, turbidity and COD removal efficiencies at optimum conditions were found to be more than 85%, 95%, and 75%, respectively.

  17. Magnetoelectronic properties of chiral carbon nanotubes and tori

    International Nuclear Information System (INIS)

    Shyu, F L; Tsai, C C; Lee, C H; Lin, M F

    2006-01-01

    Magnetoelectronic properties of chiral carbon nanotubes and toroids are studied for any magnetic field. They are sensitive to the changes in the magnitude and the direction of the magnetic field, as well as the chirality. The important differences between chiral and achiral carbon nanotubes include band symmetry, band curvature, band crossing, band-edge state, state degeneracy, band spacing, energy gap, and semiconductor-metal transition. Carbon tori also exhibit the strong chirality dependence on the field modulation of discrete states. Chiral carbon tori might differ from chiral carbon nanotubes in energy-gap modulation, density of states, and state degeneracy

  18. Method for Transformation of Weakly Magnetic Minerals (Hematite, Goethite into Strongly Magnetic Mineral (Magnetite to Improve the Efficiency of Technologies for Oxidized Iron Ores Benefication

    Directory of Open Access Journals (Sweden)

    Ponomarenko, O.

    2015-03-01

    Full Text Available A new method for relatively simple transformation of weakly magnetic minerals (goethite (α-FeOOH and hematite (α-Fe2O3 into strongly magnetic mineral (magnetite (Fe3O4 was developed. It was shown, that transformation of structure and magnetic characteristics of go ethite and hematite are realized in the presence of starch at relatively low temperatures (in the range of 300—600 °С. Obtained results open up new possibilities for development of effective technologies for oxidized iron ore beneficiation.

  19. Optical properties of titanium dioxide nanotube arrays

    Energy Technology Data Exchange (ETDEWEB)

    Abdelmoula, Mohamed [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Department of Materials Science, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Sokoloff, Jeffrey; Lu, Wen-Tao; Menon, Latika [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Close, Thomas; Richter, Christiaan, E-mail: christiaan.richter@rit.edu [Department of Chemical Engineering, Rochester Institute of Technology, Rochester, New York, 14623 (United States)

    2014-01-07

    We present experimental measurements and a theoretical analysis of the near UV to NIR optical properties of free standing titania nanotube arrays. An improved understanding of the optical physics of this type of nanostructure is important to several next generation solar energy conversion technologies. We measured the transmission, reflection, and absorption of the electromagnetic spectrum from 300 nm to 1000 nm (UV to NIR) of titania nanotube arrays. We measured the total, specular, and diffuse reflection and transmission using both single point detection and an integrating sphere spectrometer. We find that the transmission, but not the reflection, of light (UV to NIR) through the nanotube array is well-explained by classic geometric optics using an effective medium model taking into account the conical geometry of the nanotubes. For wavelengths shorter than ∼500 nm, we find the surprising result that the reflection coefficient for light incident on the open side of the nanotube array is greater than the reflection coefficient for light incident on the closed “floor” of the nanotube array. We consider theoretical models based on the eikonal approximation, photonic crystal band theory, and a statistical treatment of scattering to explain the observed data. We attribute the fact that light with wavelengths shorter than 500 nm is more highly reflected from the open than the closed tube side as being due to disorder scattering inside the nanotube array.

  20. Magnetic Field Sensors Based on Giant Magnetoresistance (GMR Technology: Applications in Electrical Current Sensing

    Directory of Open Access Journals (Sweden)

    Càndid Reig

    2009-10-01

    Full Text Available The 2007 Nobel Prize in Physics can be understood as a global recognition to the rapid development of the Giant Magnetoresistance (GMR, from both the physics and engineering points of view. Behind the utilization of GMR structures as read heads for massive storage magnetic hard disks, important applications as solid state magnetic sensors have emerged. Low cost, compatibility with standard CMOS technologies and high sensitivity are common advantages of these sensors. This way, they have been successfully applied in a lot different environments. In this work, we are trying to collect the Spanish contributions to the progress of the research related to the GMR based sensors covering, among other subjects, the applications, the sensor design, the modelling and the electronic interfaces, focusing on electrical current sensing applications.

  1. Technology requirements for fusion--fission reactors based on magnetic-mirror confinement

    International Nuclear Information System (INIS)

    Moir, R.W.

    1978-01-01

    Technology requirements for mirror hybrid reactors are discussed. The required 120-keV neutral beams can use positive ions. The magnetic fields are 8 T or under and can use NbTi superconductors. The value of Q (where Q is the ratio of fusion power to injection power) should be in the range of 1 to 2 for economic reasons relating to the cost of recirculating power. The wall loading of 14-MeV neutrons should be in the range of 1 to 2 MW/m 2 for economic reasons. Five-times higher wall loading will likely be needed if fusion reactors are to be economical. The magnetic mirror experiments 2XIIB, TMX, and MFTF are described

  2. Spanish Minister of Science and Technology visits the LHC magnet test facility

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister for Science and Technology, Spain, toured the test facility for LHC magnets in building SM18 during his visit to CERN in November. Photos 01, 02: (left to right) M. Cerrada, CERN; Francisco Giménez-Reyna, Spanish delegate to the CERN Finance Committee; G. Léon; Juan Antonio Rubio, leader of the Education and Technology Transfer division at CERN; M. Aguilar-Benitez, Spanish delegate to CERN Council; (behind) H.E. Mr Joaquin Pérez-Villanueva y Tovar, Ambassador and Permanent Representative of Spain to the United Nations in Geneva; the Minister; Manuel Delfino, leader of the Information Technology division at CERN; bodyguard; Matteo Cavalli-Sforza, ATLAS national contact physicist for Spain; Felix Rodriguez Mateos, CERN; G. Babé. Visible in the left background is one of the test benches where magnets are prepared for installation in String 2: the full-scale model of an LHC cell of the regular part of the arc. The extremity of String 2, which measures 120 m and runs the ...

  3. EXPERIMENTAL STUDIES FOR DEVELOPMENT HIGH-POWER AUDIO SPEAKER DEVICES PERFORMANCE USING PERMANENT NdFeB MAGNETS SPECIAL TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Constantin D. STĂNESCU

    2013-05-01

    Full Text Available In this paper the authors shows the research made for improving high-power audio speaker devices performance using permanent NdFeB magnets special technology. Magnetic losses inside these audio devices are due to mechanical system frictions and to thermal effect of Joules eddy currents. In this regard, by special technology, were made conical surfaces at top plate and center pin. Analysing results obtained by modelling the magnetic circuit finite element method using electronic software package,was measured increase efficiency by over 10 %, from 1,136T to13T.

  4. Nanomagnetic domains of chromium deposited on vertically-aligned carbon nanotubes

    International Nuclear Information System (INIS)

    Wright, Andrew C.; Faulkner, Michael K.; Harris, Robert C.; Goddard, Alex; Abbott, Andrew P.

    2012-01-01

    The drive to create ever smaller magnetic memory devices has led to the development of new nanomagnetic domains on surfaces. This paper reports the development of nano-chromium magnetic domains obtained using electrodeposition on vertically aligned carbon nanofibers arrays. Attempts to achieve this using conventional aqueous solutions were unsuccessful even after thin nickel underlayers were applied. The use of a novel electrolyte, a deep eutectic solvent, made from choline chloride: chromium (III) chloride enabled highly conformal overcoatings of chromium on individual bare carbon nanotubes to be obtained. Very high aspect ratio metal microstructures could be obtained by this novel technology. Magnetic imaging of the coated nanoarrays showed there to be clear magnetic character to the coating when the thin coatings were applied but this disappeared when the deposits were thicker and more contiguous. - Highlights: ► Nanoscale chromium deposited from non-aqueous electrolyte shows magnetic behavior. ► Vertically aligned carbon nanotubes conformally coated with chromium metal. ► Ionic liquid electrolyte superior to chromic acid for plating high aspect ratio structures.

  5. Nanomagnetic domains of chromium deposited on vertically-aligned carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Andrew C., E-mail: a.wright@glyndwr.ac.uk [Advanced Materials Research Laboratory, Materials Science Research Center, Glyndwr University, Wrexham LL11 2AW (United Kingdom); Faulkner, Michael K., E-mail: m.faulkner@manchester.ac.uk [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, Manchester M13 9PL (United Kingdom); Harris, Robert C.; Goddard, Alex; Abbott, Andrew P., E-mail: apa1@le.ac.uk [Department of Chemistry, University of Leicester, Leicester LE1 7RH (United Kingdom)

    2012-12-15

    The drive to create ever smaller magnetic memory devices has led to the development of new nanomagnetic domains on surfaces. This paper reports the development of nano-chromium magnetic domains obtained using electrodeposition on vertically aligned carbon nanofibers arrays. Attempts to achieve this using conventional aqueous solutions were unsuccessful even after thin nickel underlayers were applied. The use of a novel electrolyte, a deep eutectic solvent, made from choline chloride: chromium (III) chloride enabled highly conformal overcoatings of chromium on individual bare carbon nanotubes to be obtained. Very high aspect ratio metal microstructures could be obtained by this novel technology. Magnetic imaging of the coated nanoarrays showed there to be clear magnetic character to the coating when the thin coatings were applied but this disappeared when the deposits were thicker and more contiguous. - Highlights: Black-Right-Pointing-Pointer Nanoscale chromium deposited from non-aqueous electrolyte shows magnetic behavior. Black-Right-Pointing-Pointer Vertically aligned carbon nanotubes conformally coated with chromium metal. Black-Right-Pointing-Pointer Ionic liquid electrolyte superior to chromic acid for plating high aspect ratio structures.

  6. Functionalization of Carbon Nanotubes

    Science.gov (United States)

    Khare, Bishun N. (Inventor); Meyyappan, Meyya (Inventor)

    2009-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H2 or F2 or CnHm) is irradiated to provide a cold plasma of selected target species particles, such as atomic H or F, in a first chamber. The target species particles are d irected toward an array of CNTs located in a second chamber while suppressing transport of ultraviolet radiation to the second chamber. A CNT array is functionalized with the target species particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec. *Discrimination against non-target species is provided by (i) use of a target species having a lifetime that is much greater than a lifetime of a non-target species and/or (2) use of an applied magnetic field to discriminate between charged particle trajectories for target species and for non-target species.

  7. The Effect of External Magnetic Field on Dielectric Permeability of Multiphase Ferrofluids

    Science.gov (United States)

    Dotsenko, O. A.; Pavlova, A. A.; Dotsenko, V. S.

    2018-03-01

    Nowadays, ferrofluids are applied in various fields of science and technology, namely space, medicine, geology, biology, automobile production, etc. In order to investigate the feasibility of applying ferrofluids in magnetic field sensors, the paper presents research into the influence of the external magnetic field on dielectric permeability of ferrofluids comprising magnetite nanopowder, multiwall carbon nanotubes, propanetriol and deionized water. The real and imaginary parts of the dielectric permeability change respectively by 3.7 and 0.5% when applying the magnetic field parallel to the electric. The findings suggest that the considered ferrofluid can be used as a magnetic level gauge or in design of variable capacitors.

  8. Nanotubes and nanowires

    Indian Academy of Sciences (India)

    Unknown

    junction nanotubes by the pyrolysis of appropriate organic precursors. ... By making use of carbon nanotubes, nanowires of metals, metal ..... The use of activated carbon in place of ..... required for the complete removal of the carbon template.

  9. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  10. Printing nanotube/nanowire for flexible microsystems

    Science.gov (United States)

    Tortorich, Ryan P.; Choi, Jin-Woo

    2014-04-01

    Printing has become an emerging manufacturing technology for mechanics, electronics, and consumer products. Additionally, both nanotubes and nanowires have recently been used as materials for sensors and electrodes due to their unique electrical and mechanical properties. Printed electrodes and conductive traces particularly offer versatility of fabricating low-cost, disposable, and flexible electrical devices and microsystems. While various printing methods such as screen printing have been conventional methods for printing conductive traces and electrodes, inkjet printing has recently attracted great attention due to its unique advantages including no template requirement, rapid printing at low cost, on-demand printing capability, and precise control of the printed material. Computer generated conductive traces or electrode patterns can simply be printed on a thin film substrate with proper conductive ink consisting of nanotubes or nanowires. However, in order to develop nanotube or nanowire ink, there are a few challenges that need to be addressed. The most difficult obstacle to overcome is that of nanotube/nanowire dispersion within a solution. Other challenges include adjusting surface tension and controlling viscosity of the ink as well as treating the surface of the printing substrate. In an attempt to pave the way for nanomaterial inkjet printing, we present a method for preparing carbon nanotube ink as well as its printing technique. A fully printed electrochemical sensor using inkjet-printed carbon nanotube electrodes is also demonstrated as an example of the possibilities for this technology.

  11. Recent developments in the food quality detected by non-invasive nuclear magnetic resonance technology.

    Science.gov (United States)

    Fan, Kai; Zhang, Min

    2018-02-16

    Nuclear magnetic resonance (NMR) is a rapid, accurate and non-invasive technology and widely used to detect the quality of food, particularly to fruits and vegetables, meat and aquatic products. This review is a survey of recent developments in experimental results for the quality of food on various NMR technologies in processing and storage over the past decade. Following a discussion of the quality discrimination and classification of food, analysis of food compositions and detection of physical, chemical, structural and microbiological properties of food are outlined. Owing to high cost, low detection limit and sensitivity, the professional knowledge involved and the safety issues related to the maintenance of the magnetic field, so far the practical applications are limited to detect small range of food. In order to promote applications for a broader range of foods further research and development efforts are needed to overcome the limitations of NMR in the detection process. The needs and opportunities for future research and developments are outlined.

  12. Development of the Facility for Transformation of Magnetic Characteristics of Weakly Magnetic Oxidized Iron Ores Related to Improvement of Technologies for Iron Ore Concentrate Production

    Directory of Open Access Journals (Sweden)

    Ponomarenko, O.M.

    2016-01-01

    Full Text Available New facility for continuous registration of iron ore magnetization depending on temperature by heating of iron ores upon reducing conditions was created. Facility allows to register the processes of transformation of weakly magnetic minerals into strongly magnetic ones under the influence of reducing agents and temperature, as well as to determine the Curie temperature of the minerals. Using created facility it was shown, that heating of goethite and hematite in the presence of 4 % of starch in the temperature range of 300—650 °С leads to significant increase of magnetization of the samples. X-Ray diffraction confirmed that under indicated conditions the structure of hematite and goethite is transformed into magnetite structure. Obtained results open up new possibilities for the development of effective technologies for oxidized iron ore beneficiation.

  13. Electronics with carbon nanotubes

    International Nuclear Information System (INIS)

    Avouris, P.

    2007-01-01

    From mobile phones and laptops to Xboxes and iPods, it is difficult to think of any aspect of modern life that has not been touched by developments in electronics, computing and communications over the last few decades. Many of these technological advances have arisen from our ability to create ever smaller electronic devices, in particular silicon-based field effect transistors (FETs), which has led to denser, faster and less power-hungry circuits. The problem is that this device miniaturization, or 'scaling', cannot continue forever. Fundamental scientific and technological limitations exist that will make it impossible to build better performing silicon devices below a certain size. This potential show-stopper has inspired a worldwide effort to develop alternative device technologies based on 1D materials or those that exploit the spin, as well as the charge, of electrons. One promising and, in principle, simpler approach is to maintain the operating concept of today's silicon-based FETs but to replace a key component of the device - the semiconducting silicon channel - with 1D nanostructures that have much more versatile electrical-transport properties. Among the different 1D materials that have been developed, those with the most desirable properties are 'single-walled' carbon nanotubes, which were first created in 1993 by Sumio Ijima at the NEC Fundamental Research Laboratory in Tsukuba, Japan, and by Donald Bethune of IBM's Almaden Research Center in California. These materials are hollow tubes made from rolled up sheets of carbon just one atom thick, otherwise known as graphene. In the March issue of Physics World, Phaedon Avouris discusses some of the many properties and applications of carbon nanotubes, which he describes as an 'engineer's dream' because of their exceptionally high strength and heat conduction. (U.K.)

  14. Topological phase diagram of superconducting carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Milz, Lars; Marganska-Lyzniak, Magdalena; Grifoni, Milena [Institut I - Theoretische Physik Universitaet Regensburg (Germany)

    2016-07-01

    The topological superconducting phase diagram of superconducting carbon nanotubes is discussed. Under the assumption of a short-ranged pairing potential, there are two spin-singlet states: an s-wave and an exotic p + ip-wave that are possible because of the special structure of the honeycomb lattice. The consequences for the possible presence of Majorana edge states in carbon nanotubes are addressed. In particular, regions in the magnetic field-chemical potential plane possibly hosting localized Majorana modes are discussed.

  15. Development of varying magnetic field analysis technology caused by vibration of MRI apparatus

    International Nuclear Information System (INIS)

    Imamura, Yukinobu; Motoshiromizu, Hirofumi; Abe, Mitsushi; Watanabe, Hiroyuki; Takeuchi, Hiroyuki

    2015-01-01

    In Magnetic Resonance Imaging (MRI) apparatus, pulse current is energized to the gradient coils in a strong static magnetic field generated by the static magnetic poles. Since electromagnetic force (i.e. Lorentz force) is generated in the gradient coils, the MRI magnet system vibrates. On the other hand, vibration of the MRI magnet system is affected by electromagnetic force caused by static magnetic poles vibration. As the vibration of MRI magnet system causes magnetic field disturbance (so-called 'error magnetic field') and affect image quality, it is important to evaluate them in the design process. In this study, a varying magnetic field evaluation method for MRI magnet system was developed. Vibration and electromagnetic force is considered in the weak coupling formation using the Modal Magnetic Dumping (MMD) method. In the eddy current analysis by vibration, the displacement was considered in the magnetic field changes in the finite elements. Error magnetic field caused by equipment vibration was obtained by superposition of the static magnetic field fluctuation and the eddy current magnetic field. Then open type MRI magnet was evaluated by the proposed methodology. A a result, vibration of static magnet poles were suppressed by magnetic dumping at 50 Hz or less and eddy current magnetic field was dominant at 50 Hz or more. (author)

  16. Spanish Minister of Science and Technology visits the LHC magnet test facility

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister of Science and Technology, Spain, toured the test facility for LHC magnets in building SM18 during his visit to CERN in November. In this series of photos Felix Rodriguez Mateo explains the operation of the test facilty to the ministerial party. Photo 01: (left to right) Felix Rodriguez Mateo; the Minister; Francisco Giménez-Reyna, Spanish delegate to the CERN Finance Committee; M. Aguilar Benitez, Spanish delegate to the CERN Council; G. Babé and G. Léon. Photo 02: (left to right) Felix Rodriguez Mateos; César Dopazo, Director-General of CIEMAT (Spanish Research Centre for Energy, Environment and Technology); the Minister; G. Babé; M. Aguilar Benitez; and G. Léon. Photo 03: Francisco Giménez-Reyna; Felix Rodriguez Mateos; César Dopazo; the Minister; Juan Antonio Rubio, leader of the Education and Technology Transfer division at CERN; G. Babé behind M. Aguilar Benitez. Photo 04: Francisco Giménez-Reyna, partially hidden behind Felix Rodriguez Mateos; César Dop...

  17. Carbon Nanotube based Nanotechnolgy

    Science.gov (United States)

    Meyyappan, M.

    2000-10-01

    Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

  18. MAGNET

    CERN Multimedia

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  19. Dependence of the electrical properties of defective single-walled carbon nanotubes on the vacancy density

    International Nuclear Information System (INIS)

    Luo Yu-Pin; Tien Li-Gan; Tsai Chuen-Horng; Lee Ming-Hsien; Li Feng-Yin

    2011-01-01

    The relationship between the electric properties and the vacancy density in single-walled carbon nanotubes has been investigated from first principles as well as the dependence of the influencing range of a vacancy in the nanotube on the nanotube chirality. Compared with the long-range interaction of the vacancies in a single-walled carbon nanotube with non-zero chiral angle, a much shorter interaction was found between vacancies in a zigzag single-walled carbon nanotube. In this study, we investigated the bandstructure fluctuations caused by the nanotube strain, which depends on both the vacancy density and the tube chirality. These theoretical results provide new insight to understand the relationship between the local deformation of a defective single-walled carbon nanotube and its measurable electronic properties. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Local gate control in carbon nanotube quantum devices

    Science.gov (United States)

    Biercuk, Michael Jordan

    This thesis presents transport measurements of carbon nanotube electronic devices operated in the quantum regime. Nanotubes are contacted by source and drain electrodes, and multiple lithographically-patterned electrostatic gates are aligned to each device. Transport measurements of device conductance or current as a function of local gate voltages reveal that local gates couple primarily to the proximal section of the nanotube, hence providing spatially localized control over carrier density along the nanotube length. Further, using several different techniques we are able to produce local depletion regions along the length of a tube. This phenomenon is explored in detail for different contact metals to the nanotube. We utilize local gating techniques to study multiple quantum dots in carbon nanotubes produced both by naturally occurring defects, and by the controlled application of voltages to depletion gates. We study double quantum dots in detail, where transport measurements reveal honeycomb charge stability diagrams. We extract values of energy-level spacings, capacitances, and interaction energies for this system, and demonstrate independent control over all relevant tunneling rates. We report rf-reflectometry measurements of gate-defined carbon nanotube quantum dots with integrated charge sensors. Aluminum rf-SETs are electrostatically coupled to carbon nanotube devices and detect single electron charging phenomena in the Coulomb blockade regime. Simultaneous correlated measurements of single electron charging are made using reflected rf power from the nanotube itself and from the rf-SET on microsecond time scales. We map charge stability diagrams for the nanotube quantum dot via charge sensing, observing Coulomb charging diamonds beyond the first order. Conductance measurements of carbon nanotubes containing gated local depletion regions exhibit plateaus as a function of gate voltage, spaced by approximately 1e2/h, the quantum of conductance for a single

  1. Experimental investigation of an active magnetic regenerative heat circulator applied to self-heat recuperation technology

    International Nuclear Information System (INIS)

    Kotani, Yui; Kansha, Yasuki; Ishizuka, Masanori; Tsutsumi, Atsushi

    2014-01-01

    An experimental investigation into an active magnetic regenerative (AMR) heat circulator based on self-heat recuperation technology, was conducted to evaluate its energy saving potential in heat circulation. In an AMR heat circulator, magnetocaloric effect is applied to recuperate the heat exergy of the process fluid. The recuperated heat can be reused to heat the feed process fluid and realize self-heat recuperation. In this paper, AMR heat circulator has newly been constructed to determine the amount of heat circulated when applied to self-heat recuperation and the energy consumption of the heat circulator. Gadolinium and water was used as the magnetocaloric working material and the process fluid, respectively. The heat circulated amount was determined by measuring the temperature of the process fluid and gadolinium. The net work input for heat circulation was obtained from the magnetizing and demagnetizing forces and the distance travelled by the magnetocaloric bed. The results were compared with the minimum work input needed for heat circulation derived from exergy loss during heat exchange. It was seen that the experimentally obtained value was close to the minimum work input needed for heat circulation. - Highlights: • AMR heat circulator has newly been constructed for experimental evaluation. • Heat circulation in the vicinity of Curie temperature was observed. • Energy consumption of an AMR heat circulator has been measured. • Energy saving for processes near Curie temperature of working material was seen

  2. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.; Cachim, P.B.; Da Costa, Pedro M. F. J.

    2014-01-01

    The benefits of filling carbon nanotubes (CNTs) with assorted molecular and crystalline substances have been investigated for the past two decades. Amongst the study of new structural phases, defects, chemical reactions and varied types of host-guest interactions, there is one fundamental characterisation aspect of these systems that continues to be overlooked: the mechanical behaviour of filled CNTs. In contrast to their empty counterparts, the mechanics of filled CNTs is a subject where reports appear far and apart, this despite being key to the application of these materials in technological devices. In the following paragraphs, we review the work that has been carried out up to the present on the mechanics of filled CNTs. The studies discussed range from experimental resonant frequency essays performed within electron microscopes to modelling, via molecular dynamics, of three-point bending of nanotubes filled with gases. (C) 2014 Elsevier B.V. All rights reserved.

  3. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.

    2014-04-01

    The benefits of filling carbon nanotubes (CNTs) with assorted molecular and crystalline substances have been investigated for the past two decades. Amongst the study of new structural phases, defects, chemical reactions and varied types of host-guest interactions, there is one fundamental characterisation aspect of these systems that continues to be overlooked: the mechanical behaviour of filled CNTs. In contrast to their empty counterparts, the mechanics of filled CNTs is a subject where reports appear far and apart, this despite being key to the application of these materials in technological devices. In the following paragraphs, we review the work that has been carried out up to the present on the mechanics of filled CNTs. The studies discussed range from experimental resonant frequency essays performed within electron microscopes to modelling, via molecular dynamics, of three-point bending of nanotubes filled with gases. (C) 2014 Elsevier B.V. All rights reserved.

  4. Carbon nanotubes in neuroregeneration and repair.

    Science.gov (United States)

    Fabbro, Alessandra; Prato, Maurizio; Ballerini, Laura

    2013-12-01

    In the last decade, we have experienced an increasing interest and an improved understanding of the application of nanotechnology to the nervous system. The aim of such studies is that of developing future strategies for tissue repair to promote functional recovery after brain damage. In this framework, carbon nanotube based technologies are emerging as particularly innovative tools due to the outstanding physical properties of these nanomaterials together with their recently documented ability to interface neuronal circuits, synapses and membranes. This review will discuss the state of the art in carbon nanotube technology applied to the development of devices able to drive nerve tissue repair; we will highlight the most exciting findings addressing the impact of carbon nanotubes in nerve tissue engineering, focusing in particular on neuronal differentiation, growth and network reconstruction. © 2013.

  5. Tuning of graphene nanoribbon Landau levels by a nanotube

    International Nuclear Information System (INIS)

    Li, T S; Chang, S C; Lin, M F

    2009-01-01

    We investigate theoretically the effects of a nanotube on the graphene nanoribbon Landau level spectrum utilizing the tight-binding model. The addition of a nanotube changes the original dispersionless Landau subbands into distorted parabolic ones, creates additional band-edge states, and modifies the subband spacings. Moreover, the dispersion relations rely sensitively on the nanotube location. The nanotube-ribbon couplings disrupt the Landau wavefunctions and lift their spatial symmetry, which will change the selection rule of optical transitions. The numbers, frequencies and heights of the density of states (DOS) peaks are found to be strongly dependent on the magnetic flux density and the nanotube location. The evolution of the DOS peak with the magnetic flux density is explored. The graphene nanoribbon Landau levels are shown to be modified in an unexpected fashion by the nanotube-ribbon interactions. These predictions can be validated by measuring the spectra of scanning tunneling experiments or magneto-optical experiments, and they are most observable by placing the nanotube at the electron wavefunction localization sites.

  6. Strain-modified RKKY interaction in carbon nanotubes

    DEFF Research Database (Denmark)

    Gorman, P. D.; Duffy, J. M.; Power, Stephen R.

    2015-01-01

    been shown that the interaction range depends on the conformation of the magnetic dopants in both graphene and nanotubes. Here we examine the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in carbon nanotubes in the presence of uniaxial strain for a range of different impurity configurations. We show......For low-dimensionalmetallic structures, such as nanotubes, the exchange coupling between localized magnetic dopants is predicted to decay slowly with separation. The long-range character of this interaction plays a significant role in determining the magnetic order of the system. It has previously...... that strain is capable of amplifying or attenuating the RKKY interaction, significantly increasing certain interaction ranges, and acting as a switch: effectively turning on or off the interaction. We argue that uniaxial strain can be employed to significantly manipulate magnetic interactions in carbon...

  7. Methods Reduce Cost, Enhance Quality of Nanotubes

    Science.gov (United States)

    2009-01-01

    For all the challenges posed by the microgravity conditions of space, weight is actually one of the more significant problems NASA faces in the development of the next generation of U.S. space vehicles. For the Agency s Constellation Program, engineers at NASA centers are designing and testing new vessels as safe, practical, and cost-effective means of space travel following the eventual retirement of the space shuttle. Program components like the Orion Crew Exploration Vehicle, intended to carry astronauts to the International Space Station and the Moon, must be designed to specific weight requirements to manage fuel consumption and match launch rocket capabilities; Orion s gross liftoff weight target is about 63,789 pounds. Future space vehicles will require even greater attention to lightweight construction to help conserve fuel for long-range missions to Mars and beyond. In order to reduce spacecraft weight without sacrificing structural integrity, NASA is pursuing the development of materials that promise to revolutionize not only spacecraft construction, but also a host of potential applications on Earth. Single-walled carbon nanotubes are one material of particular interest. These tubular, single-layer carbon molecules - 100,000 of them braided together would be no thicker than a human hair - display a range of remarkable characteristics. Possessing greater tensile strength than steel at a fraction of the weight, the nanotubes are efficient heat conductors with metallic or semiconductor electrical properties depending on their diameter and chirality (the pattern of each nanotube s hexagonal lattice structure). All of these properties make the nanotubes an appealing material for spacecraft construction, with the potential for nanotube composites to reduce spacecraft weight by 50 percent or more. The nanotubes may also feature in a number of other space exploration applications, including life support, energy storage, and sensor technologies. NASA s various

  8. Carbon Nanotubes Hybrid Hydrogels in Drug Delivery: A Perspective Review

    Science.gov (United States)

    Hampel, Silke; Spizzirri, Umile Gianfranco; Parisi, Ortensia Ilaria; Picci, Nevio; Iemma, Francesca

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review. PMID:24587993

  9. FeNi nanotubes: perspective tool for targeted delivery

    Science.gov (United States)

    Kaniukov, Egor; Shumskaya, Alena; Yakimchuk, Dzmitry; Kozlovskiy, Artem; Korolkov, Ilya; Ibragimova, Milana; Zdorovets, Maxim; Kadyrzhanov, Kairat; Rusakov, Vyacheslav; Fadeev, Maxim; Lobko, Eugenia; Saunina, Kristina; Nikolaevich, Larisa

    2018-05-01

    Targeted delivery of drugs and proteins by magnetic field is a promising method to treat cancer that reduces undesired systemic toxicity of drugs. In this method, the therapeutic agent is attached through links to functional groups with magnetic nanostructure and injected into the blood to be transported to the problem area. To provide a local effect of drug treatment, nanostructures are concentrated and fixed in the selected area by the external magnetic field (magnet). After the exposure, carriers are removed from the circulatory system by magnetic field. In this study, Fe20Ni80 nanotubes are considered as carriers for targeted delivery of drugs and proteins. A simple synthesis method is proposed to form these structures by electrodeposition in PET template pores, and structural and magnetic properties are studied in detail. Nanotubes have polycrystalline walls providing mechanical strength of carriers and magnetic anisotropy that allow controlling the nanostructure movement under the exposure of by magnetic field. Moreover, potential advantages of magnetic nanotubes are discussed in comparison with other carrier types. Most sufficient of them is predictable behavior in magnetic field due to the absence of magnetic core, low specific density that allows floating in biological media, and large specific surface area providing the attachment of a larger number of payloads for the targeted delivery. A method of coating nanotube surfaces with PMMA is proposed to exclude possible negative impact of the carrier material and to form functional bonds for the payload connection. Cytotoxicity studies of coated and uncoated nanotubes are carried out to understand their influence on the biological media.

  10. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

  11. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

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

  12. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

  13. Carbon nanotube computer.

    Science.gov (United States)

    Shulaker, Max M; Hills, Gage; Patil, Nishant; Wei, Hai; Chen, Hong-Yu; Wong, H-S Philip; Mitra, Subhasish

    2013-09-26

    The miniaturization of electronic devices has been the principal driving force behind the semiconductor industry, and has brought about major improvements in computational power and energy efficiency. Although advances with silicon-based electronics continue to be made, alternative technologies are being explored. Digital circuits based on transistors fabricated from carbon nanotubes (CNTs) have the potential to outperform silicon by improving the energy-delay product, a metric of energy efficiency, by more than an order of magnitude. Hence, CNTs are an exciting complement to existing semiconductor technologies. Owing to substantial fundamental imperfections inherent in CNTs, however, only very basic circuit blocks have been demonstrated. Here we show how these imperfections can be overcome, and demonstrate the first computer built entirely using CNT-based transistors. The CNT computer runs an operating system that is capable of multitasking: as a demonstration, we perform counting and integer-sorting simultaneously. In addition, we implement 20 different instructions from the commercial MIPS instruction set to demonstrate the generality of our CNT computer. This experimental demonstration is the most complex carbon-based electronic system yet realized. It is a considerable advance because CNTs are prominent among a variety of emerging technologies that are being considered for the next generation of highly energy-efficient electronic systems.

  14. Proceedings of the third symposium on the physics and technology of compact toroids in the magnetic fusion energy program

    International Nuclear Information System (INIS)

    Siemon, R.E.

    1981-03-01

    This document contains papers contributed by the participants of the Third Symposium on Physics and Technology of Compact Toroids in the Magnetic Fusion Energy Program. Subjects include reactor aspects of compact toroids, energetic particle rings, spheromak configurations (a mixture of toroidal and poloidal fields), and field-reversed configurations

  15. Purification of carbon nanotubes via selective heating

    Science.gov (United States)

    Rogers, John A.; Wilson, William L.; Jin, Sung Hun; Dunham, Simon N.; Xie, Xu; Islam, Ahmad; Du, Frank; Huang, Yonggang; Song, Jizhou

    2017-11-21

    The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

  16. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  17. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

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

  18. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  19. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

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

  20. Carbon nanotube forests growth using catalysts from atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bingan; Zhang, Can; Esconjauregui, Santiago; Xie, Rongsi; Zhong, Guofang; Robertson, John [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Bhardwaj, Sunil [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy); Sincrotone Trieste S.C.p.A., s.s. 14, km 163.4, I-34149 Trieste (Italy); Cepek, Cinzia [Istituto Officina dei Materiali-CNR Laboratorio TASC, s.s. 14, km 163.4, I-34012 Trieste (Italy)

    2014-04-14

    We have grown carbon nanotubes using Fe and Ni catalyst films deposited by atomic layer deposition. Both metals lead to catalytically active nanoparticles for growing vertically aligned nanotube forests or carbon fibres, depending on the growth conditions and whether the substrate is alumina or silica. The resulting nanotubes have narrow diameter and wall number distributions that are as narrow as those grown from sputtered catalysts. The state of the catalyst is studied by in-situ and ex-situ X-ray photoemission spectroscopy. We demonstrate multi-directional nanotube growth on a porous alumina foam coated with Fe prepared by atomic layer deposition. This deposition technique can be useful for nanotube applications in microelectronics, filter technology, and energy storage.

  1. Rotational actuator of motor based on carbon nanotubes

    Science.gov (United States)

    Zettl, Alexander K.; Fennimore, Adam M.; Yuzvinsky, Thomas D.

    2008-11-18

    A rotational actuator/motor based on rotation of a carbon nanotube is disclosed. The carbon nanotube is provided with a rotor plate attached to an outer wall, which moves relative to an inner wall of the nanotube. After deposit of a nanotube on a silicon chip substrate, the entire structure may be fabricated by lithography using selected techniques adapted from silicon manufacturing technology. The structures to be fabricated may comprise a multiwall carbon nanotube (MWNT), two in plane stators S1, S2 and a gate stator S3 buried beneath the substrate surface. The MWNT is suspended between two anchor pads and comprises a rotator attached to an outer wall and arranged to move in response to electromagnetic inputs. The substrate is etched away to allow the rotor to freely rotate. Rotation may be either in a reciprocal or fully rotatable manner.

  2. Chemistry of Carbon Nanotubes for Everyone

    Science.gov (United States)

    Basu-Dutt, Sharmistha; Minus, Marilyn L.; Jain, Rahul; Nepal, Dhriti; Kumar, Satish

    2012-01-01

    Carbon nanotubes (CNTs) have the extraordinary potential to change our lives by improving existing products and enabling new ones. Current and future research and industrial workforce professionals are very likely to encounter some aspects of nanotechnology including CNT science and technology in their education or profession. The simple structure…

  3. Self-grafting carbon nanotubes on polymers for stretchable electronics

    Science.gov (United States)

    Morales, Piero; Moyanova, Slavianka; Pavone, Luigi; Fazi, Laura; Mirabile Gattia, Daniele; Rapone, Bruno; Gaglione, Anderson; Senesi, Roberto

    2018-06-01

    Elementary bidimensional circuitry made of single-wall carbon-nanotube-based conductors, self-grafted on different polymer films, is accomplished in an attempt to develop a simple technology for flexible and stretchable electronic devices. Unlike in other studies of polymer-carbon nanotube composites, no chemical functionalization of single-wall carbon nanotubes is necessary for stable grafting onto several polymeric surfaces, suggesting viable and cheap fabrication technologies for stretchable microdevices. Electrical characterization of both unstretched and strongly stretched conductors is provided, while an insight on the mechanisms of strong adhesion to the polymer is obtained by scanning electron microscopy of the surface composite. As a first example of technological application, the electrical functionality of a carbon-nanotube-based 6-sensor (electrode) grid was demonstrated by recording of subdural electrocorticograms in freely moving rats over approximately three months. The results are very promising and may serve as a basis for future work targeting clinical applications.

  4. Status of teaching elementary science for English learners in science, mathematics and technology centered magnet schools

    Science.gov (United States)

    Han, Alyson Kim

    According to the California Commission on Teacher Credentialing (2001), one in three students speaks a language other than English. Additionally, the Commission stated that a student is considered to be an English learner if the second language acquisition is English. In California more than 1.4 million English learners enter school speaking a variety of languages, and this number continues to rise. There is an imminent need to promote instructional strategies that support this group of diverse learners. Although this was not a California study, the results derived from the nationwide participants' responses provided a congruent assessment of the basic need to provide effective science teaching strategies to all English learners. The purpose of this study was to examine the status of elementary science teaching practices used with English learners in kindergarten through fifth grade in public mathematics, science, and technology-centered elementary magnet schools throughout the country. This descriptive research was designed to provide current information and to identify trends in the areas of curriculum and instruction for English learners in science themed magnet schools. This report described the status of elementary (grades K-5) school science instruction for English learners based on the responses of 116 elementary school teachers: 59 grade K-2, and 57 grade 3-5 teachers. Current research-based approaches support incorporating self-directed learning strategy, expository teaching strategy, active listening strategies, questioning strategies, wait time strategy, small group strategy, peer tutoring strategy, large group learning strategy, demonstrations strategy, formal debates strategy, review sessions strategy, mediated conversation strategy, cooperative learning strategy, and theme-based instruction into the curriculum to assist English learners in science education. Science Technology Society (STS) strategy, problem-based learning strategy, discovery learning

  5. Development of dual field magnetic flux leakage (MFL) inspection technology to detect mechanical damage.

    Science.gov (United States)

    2013-03-01

    This report details the development and testing of a dual magnetization in-line inspection (ILI) : tool for detecting mechanical damage in operating pipelines, including the first field trials of a : fully operational dual-field magnetic flux leakage...

  6. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

  7. Characterizing gas shaly sandstone reservoirs using the magnetic resonance technology in the Anaco area, East Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Fam, Maged; August, Howard [Halliburton, Houston, TX (United States); Zambrano, Carlos; Rivero, Fidel [PDVSA Gas (Venezuela)

    2008-07-01

    With demand for natural gas on the rise every day, accounting for and booking every cubic foot of gas is becoming very important to operators exploiting natural gas reservoirs. The initial estimates of gas reserves are usually established through the use of petrophysical parameters normally based on wireline and/or LWD logs. Conventional logs, such as gamma ray, density, neutron, resistivity and sonic, are traditionally used to calculate these parameters. Sometimes, however, the use of such conventional logs may not be enough to provide a high degree of accuracy in determining these petrophysical parameters, which are critical to reserve estimates. Insufficient accuracy can be due to high complexities in the rock properties and/or a formation fluid distribution within the reservoir layers that is very difficult to characterize with conventional logs alone. The high degree of heterogeneity in the shaly sandstone rock properties of the Anaco area, East Venezuela, can be characterized by clean, high porosity, high permeability sands to very shaly, highly laminated, and low porosity rock. This wide variation in the reservoir properties may pose difficulties in identifying gas bearing zones which may affect the final gas reserves estimates in the area. The application of the magnetic resonance imaging (MRI) logging technology in the area, combined with the application of its latest acquisition and interpretation methods, has proven to be very adequate in detecting and quantifying gas zones as well as providing more realistic petrophysical parameters for better reserve estimates. This article demonstrates the effectiveness of applying the MRI logging technology to obtain improved petrophysical parameters that will help better characterize the shaly-sands of Anaco area gas reservoirs. This article also demonstrates the value of MRI in determining fluid types, including distinguishing between bound water and free water, as well as differentiating between gas and liquid

  8. Carbon nanotubes: Sensor properties. A review

    Directory of Open Access Journals (Sweden)

    Irina V. Zaporotskova

    2016-12-01

    Full Text Available Recent publications dealing with dealing with the fabrication of gas and electrochemical biosensors based on carbon nanotubes have been reviewed. Experimental and theoretical data on the working principles of nanotubes have been presented. The main regularities of the structure, energy parameters and sensor properties of modified semiconducting systems on the basis of cabon nanotubes have been studied by analyzing the mechanisms of nanotubule interaction with functional groups (including carboxyl and amino groups, metallic nanoparticles and polymers leading to the formation of chemically active sensors. The possibility of using boundary modified nanotubes for the identification of metals has been discussed. Simulation results have been reported for the interaction of nanotubes boundary modified by –СООН and –NH2 groups with atoms and ions of potassium, sodium and lithium. The simulation has been carried out using the molecular cluster model and the MNDO and DFT calculation methods. Sensors fabricated using this technology will find wide application for the detection of metallic atoms and their ions included in salts and alkali.

  9. Challenges of in-vacuum and cryogenic permanent magnet undulator technologies

    Directory of Open Access Journals (Sweden)

    Jui-Che Huang

    2017-06-01

    Full Text Available An in-vacuum undulator (IVU provides a means to reach high-brilliance x rays in medium energy storage rings. The development of short period undulators with low phase errors creates the opportunity for an unprecedented brilliant light source in a storage ring. Since the spectral quality from cryogenic permanent magnet undulators (CPMUs has surpassed that of IVUs, NdFeB or PrFeB CPMUs have been proposed for many new advanced storage rings to reach high brilliance x-ray photon beams. In a low emittance ring, not only the performance of the undulator but also the choice of the lattice functions are important design considerations. Optimum betatron functions and a zero-dispersion function shall be provided in the straight sections for IVU/CPMUs. In this paper, relevant factors and design issues for IVUs and CPMUs are discussed together with many technological challenges in short period undulators associated with beam induced–heat load, phase errors, and the deformation of support girders.

  10. Challenges of in-vacuum and cryogenic permanent magnet undulator technologies

    Science.gov (United States)

    Huang, Jui-Che; Kitamura, Hideo; Yang, Chin-Kang; Chang, Cheng-Hsing; Chang, Cheng-Hsiang; Hwang, Ching-Shiang

    2017-06-01

    An in-vacuum undulator (IVU) provides a means to reach high-brilliance x rays in medium energy storage rings. The development of short period undulators with low phase errors creates the opportunity for an unprecedented brilliant light source in a storage ring. Since the spectral quality from cryogenic permanent magnet undulators (CPMUs) has surpassed that of IVUs, NdFeB or PrFeB CPMUs have been proposed for many new advanced storage rings to reach high brilliance x-ray photon beams. In a low emittance ring, not only the performance of the undulator but also the choice of the lattice functions are important design considerations. Optimum betatron functions and a zero-dispersion function shall be provided in the straight sections for IVU/CPMUs. In this paper, relevant factors and design issues for IVUs and CPMUs are discussed together with many technological challenges in short period undulators associated with beam induced-heat load, phase errors, and the deformation of support girders.

  11. Space Technology 5 Multi-point Measurements of Near-Earth Magnetic Fields: Initial Results

    Science.gov (United States)

    Slavin, James A.; Le, G.; Strangeway, R. L.; Wang, Y.; Boardsen, S.A.; Moldwin, M. B.; Spence, H. E.

    2007-01-01

    The Space Technology 5 (ST-5) mission successfully placed three micro-satellites in a 300 x 4500 km dawn-dusk orbit on 22 March 2006. Each spacecraft carried a boom-mounted vector fluxgate magnetometer that returned highly sensitive and accurate measurements of the geomagnetic field. These data allow, for the first time, the separation of temporal and spatial variations in field-aligned current (FAC) perturbations measured in low-Earth orbit on time scales of approximately 10 sec to 10 min. The constellation measurements are used to directly determine field-aligned current sheet motion, thickness and current density. In doing so, we demonstrate two multi-point methods for the inference of FAC current density that have not previously been possible in low-Earth orbit; 1) the "standard method," based upon s/c velocity, but corrected for FAC current sheet motion, and 2) the "gradiometer method" which uses simultaneous magnetic field measurements at two points with known separation. Future studies will apply these methods to the entire ST-5 data set and expand to include geomagnetic field gradient analyses as well as field-aligned and ionospheric currents.

  12. Optimizing magnetic nanoparticles for drinking water technology: The case of Cr(VI).

    Science.gov (United States)

    Simeonidis, K; Kaprara, E; Samaras, T; Angelakeris, M; Pliatsikas, N; Vourlias, G; Mitrakas, M; Andritsos, N

    2015-12-01

    The potential of magnetite nanoparticles to be applied in drinking water treatment for the removal of hexavalent chromium is discussed. In this study, a method for their preparation which combines the use of low-cost iron sources (FeSO4 and Fe2(SO4)3) and a continuous flow mode, was developed. The produced magnetite nanoparticles with a size of around 20 nm, appeared relatively stable to passivation providing a removal capacity of 1.8 μg Cr(VI)/mg for a residual concentration of 50 μg/L when tested in natural water at pH7. Such efficiency is explained by the reducing ability of magnetite which turns Cr(VI) to an insoluble Cr(OH)3 form. The successful operation of a small-scale system consisting of a contact reactor and a magnetic separator demonstrates a way for the practical introduction and recovery of magnetite nanoparticles in water treatment technology. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Advancing Cardiovascular, Neurovascular and Renal Magnetic Resonance Imaging in Small Rodents Using Cryogenic Radiofrequency Coil Technology

    Directory of Open Access Journals (Sweden)

    Thoralf eNiendorf

    2015-11-01

    Full Text Available Research in pathologies of the brain, heart and kidney have gained immensely from the plethora of studies that have helped shape new methods in magnetic resonance (MR for characterizing preclinical disease models. Methodical probing into preclinical animal models by MR is invaluable since it allows a careful interpretation and extrapolation of data derived from these models to human disease. In this review we will focus on the applications of cryogenic radiofrequency (RF coils in small animal MR as a means of boosting image quality (e.g. by supporting MR microscopy and making data acquisition more efficient (e.g. by reducing measuring time; both being important constituents for thorough investigational studies on animal models of disease. This review attempts to make the (biomedical imaging, molecular medicine and pharmaceutical communities aware of this productive ferment and its outstanding significance for anatomical and functional MR in small rodents. The goal is to inspire a more intense interdisciplinary collaboration across the fields to further advance and progress non-invasive MR methods that ultimately support thorough (pathophysiological characterization of animal disease models. In this review, current and potential future applications for the RF coil technology in cardiovascular, neurovascular and renal disease will be discussed.

  14. Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.

    Science.gov (United States)

    Sakudo, Akikazu; Chou, Han; Nagatsu, Masaaki

    2015-03-01

    Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Carbon nanotube woven textile photodetector

    Science.gov (United States)

    Zubair, Ahmed; Wang, Xuan; Mirri, Francesca; Tsentalovich, Dmitri E.; Fujimura, Naoki; Suzuki, Daichi; Soundarapandian, Karuppasamy P.; Kawano, Yukio; Pasquali, Matteo; Kono, Junichiro

    2018-01-01

    The increasing interest in mobile and wearable technology demands the enhancement of functionality of clothing through incorporation of sophisticated architectures of multifunctional materials. Flexible electronic and photonic devices based on organic materials have made impressive progress over the past decade, but higher performance, simpler fabrication, and most importantly, compatibility with woven technology are desired. Here we report on the development of a weaved, substrateless, and polarization-sensitive photodetector based on doping-engineered fibers of highly aligned carbon nanotubes. This room-temperature-operating, self-powered detector responds to radiation in an ultrabroad spectral range, from the ultraviolet to the terahertz, through the photothermoelectric effect, with a low noise-equivalent power (a few nW/Hz 1 /2) throughout the range and with a Z T -factor value that is twice as large as that of previously reported carbon nanotube-based photothermoelectric photodetectors. Particularly, we fabricated a ˜1 -m-long device consisting of tens of p+-p- junctions and weaved it into a shirt. This device demonstrated a collective photoresponse of the series-connected junctions under global illumination. The performance of the device did not show any sign of deterioration through 200 bending tests with a bending radius smaller than 100 μ m as well as standard washing and ironing cycles. This unconventional photodetector will find applications in wearable technology that require detection of electromagnetic radiation.

  16. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

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

  17. MAGNET

    CERN Multimedia

    B. Curé

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

  18. MAGNET

    CERN Multimedia

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  19. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

    The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

  20. Rapid and accurate biofuel moisture content gauging using magnetic resonance measurement technology

    Energy Technology Data Exchange (ETDEWEB)

    Jaervinen, T.

    2013-04-15

    Biomass is extensively utilised in energy production and as a raw material, such as for the production of liquid biofuels. All those processes will benefit if the moisture content of bio material is known in advance as accurately as possible under transient circumstances. Biofuel trade is increasingly based on the calorific value of fuels. In the first step, this also increases the need for rapid and accurate moisture content determination. During the last few years, large biofuel standardisation has been implemented, emphasising biofuel quality control at all stages of the utilisation chain. In principle, the moisture instrumental measurement can be utilised by many technologies and procedures. Typical techniques are infrared, radiofrequency, microwave, radiometric, electrical conductivity, capacitance, and impedance. Nuclear magnetic resonance (MR) and thermal neutron absorption are also applied. The MR measurement principle has been known and utilised already since the early 1950s. It has become the basic instrumental analysis tool in chemistry. It is also well-known as a very accurate method for analysing most compounds, especially substances containing hydrogen. The utilisation of MR metering is expanded extensively to medical diagnostics as a form of magnetic resonance imaging (MRI). Because of the precision of the MR principle, there have for a long time been efforts to apply it in new and different areas, and to make more user-friendly, smaller, and even portable devices. Such a device was designed by Vaisala a few years ago. VTT has utilised Vaisala's MR prototype for approximately one year for moisture content measurement of different biofuels. The first step in the use of an MR device for moisture determination was the definition of its measurement accuracy compared to the standard method (EN 14774). Those tests proved that the absolute precision seems to be comparable to the standard moisture content measurement method. It was also found out that

  1. Iron oxide nanotubes synthesized via template-based electrodeposition

    Science.gov (United States)

    Lim, Jin-Hee; Min, Seong-Gi; Malkinski, Leszek; Wiley, John B.

    2014-04-01

    Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition. In the case of magnetite nanotubes, which consist of slightly larger nanoparticles, magnetization curves show ferromagnetism with weak coercivity at room temperature, while FC-ZFC curves exhibit the Verwey transition at 125 K.Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition

  2. Technological challenges in Magnetic Resonance Imaging: enhancing sensitivity, moving to quantitative imaging and searching for disease biomarkers

    Science.gov (United States)

    Retico, A.

    2018-02-01

    Diagnostic imaging based on the Nuclear Magnetic Resonance phenomenon has increasingly spread in the recent few decades, mainly owing to its exquisite capability in depicting a contrast between soft tissues, to its generally non-invasive nature, and to the priceless advantage of using non-ionizing radiation. Magnetic Resonance (MR)-based acquisition techniques allow gathering information on the structure (through Magnetic Resonance Imaging— MRI), the metabolic composition (through Magnetic Resonance Spectroscopy—MRS), and the functioning (through functional MRI —fMRI) of the human body. MR investigations are the methods of choice for studying the brain in vivo, including anatomy, structural wiring and functional connectivity, in healthy and pathological conditions. Alongside the efforts of the clinical research community in extending the acquisition protocols to allow the exploration of a large variety of pathologies affecting diverse body regions, some relevant technological improvements are on the way to maximize the impact of MR in medical diagnostic. The development of MR scanners operating at ultra-high magnetic field (UHF) strength (>= 7 tesla), is pushing forward the spatial resolution of MRI and the spectral resolution of MRS, and it is increasing the specificity of fMRI to grey matter signal. UHF MR systems are currently in use for research purposes only; nevertheless, UHF technological advances are positively affecting MR investigations at clinical field strengths. To overcome the current major limitation of MRI, which is mostly based on contrast between tissues rather than on absolute measurements of physical quantities, a new acquisition modality is under development, which is referred as Magnetic Resonance Fingerprinting technique. Finally, as neuroimaging data acquired worldwide are reaching the typical size of Big Data, dedicated technical solutions are required to mine large amount of information and to identify specific biomarkers of

  3. Optimized design on condensing tubes high-speed TIG welding technology magnetic control based on genetic algorithm

    Science.gov (United States)

    Lu, Lin; Chang, Yunlong; Li, Yingmin; Lu, Ming

    2013-05-01

    An orthogonal experiment was conducted by the means of multivariate nonlinear regression equation to adjust the influence of external transverse magnetic field and Ar flow rate on welding quality in the process of welding condenser pipe by high-speed argon tungsten-arc welding (TIG for short). The magnetic induction and flow rate of Ar gas were used as optimum variables, and tensile strength of weld was set to objective function on the base of genetic algorithm theory, and then an optimal design was conducted. According to the request of physical production, the optimum variables were restrained. The genetic algorithm in the MATLAB was used for computing. A comparison between optimum results and experiment parameters was made. The results showed that the optimum technologic parameters could be chosen by the means of genetic algorithm with the conditions of excessive optimum variables in the process of high-speed welding. And optimum technologic parameters of welding coincided with experiment results.

  4. NMR study of local diamagnetic properties of carbon structures with multiwalled nanotubes

    International Nuclear Information System (INIS)

    Nikolaev, E.G.; Omel'yanovsky, O.E.; Prudkovsky, V.S.; Sadakov, A.V.; Tsebro, V.I.

    2009-01-01

    The reasons for the high diamagnetic susceptibility of carbon columns, which are covered with a nanotube mesh, from the interior part of cathode deposits have been studied by means of NMR. A comparative study is made of the 13 C NMR spectra and the magnetic susceptibility of carbon columns before and after ultrasonic processing as well as of finely dispersed material, obtained as a result of such processing, enriched with multilayer nanotubes. The strong diamagnetism of the carbon columns is apparently associated with a quite dense conglomerate of graphite particles, nanotubes, and multilayer polyhedral particles present in their core and not with the surface mesh of multilayer nanotubes. To make a more accurate determination of the character of the anisotropy of the magnetic susceptibility of multilayer carbon nanotubes, the form of the 13 C NMR spectra of samples enriched with multilayer nanotubes, where the nanotubes are either not oriented or only partially oriented, is analyzed. It is shown that the diamagnetic susceptibility of multilayer carbon nanotubes is highest when the magnetic field is oriented perpendicular to their axis

  5. Ultra-High Field NMR and MRI—The Role of Magnet Technology to Increase Sensitivity and Specificity

    Directory of Open Access Journals (Sweden)

    Ewald Moser

    2017-08-01

    Full Text Available “History, of course, is difficult to write, if for no other reason, than that it has so many players and so many authors.” – P. J. Keating (former Australian Prime MinisterStarting with post-war developments in nuclear magnetic resonance (NMR a race for stronger and stronger magnetic fields has begun in the 1950s to overcome the inherently low sensitivity of this promising method. Further challenges were larger magnet bores to accommodate small animals and eventually humans. Initially, resistive electromagnets with small pole distances, or sample volumes, and field strengths up to 2.35 T (or 100 MHz 1H frequency were used in applications in physics, chemistry, and material science. This was followed by stronger and more stable (Nb-Ti based superconducting magnet technology typically implemented first for small-bore systems in analytical chemistry, biochemistry and structural biology, and eventually allowing larger horizontal-bore magnets with diameters large enough to fit small laboratory animals. By the end of the 1970s, first low-field resistive magnets big enough to accommodate humans were developed and superconducting whole-body systems followed. Currently, cutting-edge analytical NMR systems are available at proton frequencies up to 1 GHz (23.5 T based on Nb3Sn at 1.9 K. A new 1.2 GHz system (28 T at 1.9 K, operating in persistent mode but using a combination of low and high temperature multi-filament superconductors is to be released. Preclinical instruments range from small-bore animal systems with typically 600–800 MHz (14.1–18.8 T up to 900 MHz (21 T at 1.9 K. Human whole-body MRI systems currently operate up to 10.5 T. Hybrid combined superconducting and resistive electromagnets with even higher field strength of 45 T dc and 100 T pulsed, are available for material research, of course with smaller free bore diameters. This rather costly development toward higher and higher field strength is a consequence of the inherently low

  6. Advances in Fiber Optic Sensors Technology Development for temperature and strain measurements in Superconducting magnets and devices

    CERN Document Server

    Chiuchiolo, A.; Bajko, M.; Bottura, L.; Consales, M.; Cusano, A.; Giordano, M.; Perez, J. C.

    2016-01-01

    The luminosity upgrade of the Large Hadron Collider (HL-LHC) requires the development of a new generation of superconducting magnets based on Nb$_{3}$Sn technology. In order to monitor the magnet thermo-mechanical behaviour during its service life, from the coil fabrication to the magnet operation, reliable sensing systems need to be implemented. In the framework of the FP7 European project EUCARD, Nb$_{3}$Sn racetrack coils are developed as test beds for the fabrication validation, the cable characterization and the instrumentation development. Fiber optic sensors (FOS) based on Fiber Bragg Grating (FBG) technology have been embedded in the coils of the Short Model Coil (SMC) magnet. The FBG sensitivity to both temperature and strain required the development of a solution able to separate the mechanical and temperature effects. This work presents the feasibility study of the implementation of embedded FBG sensors for the temperature and strain monitoring of the 11 T type conductor. We aim to monitor and regi...

  7. Applications of Magnetic Water Technology in Farming and Agriculture Development: A Review of Recent Advances

    OpenAIRE

    Yadollahpour Ali; Rashidi Samaneh; Fatemeh Kavakebian

    2014-01-01

    Magnetic water treatment (MWT) techniques have shown promising potentials in different areas specially agriculture. Safety, compatibility and simplicity, environmentally friendliness, low operating cost and not proven harmful effects are the main advantages of electromagnetic field (EMF) over conventional methods for water treatment. Magnetized or magnetic water (MW) possesses unique physical and chemical characteristics making it a multi-purpose compound with potential benefits in medical tr...

  8. Technology transfer for industrial production of superconducting magnets for the RHIC project at BNL

    International Nuclear Information System (INIS)

    Wanderer, P.; Anerella, M.D.; Greene, A.F.; Kelly, E.; Willen, E.

    1994-01-01

    Industrial production of superconducting magnets for the Relativistic Heavy Ion Collider (RHIC) has begun. The R ampersand D for the magnets was carried out at BNL. Following the award of built-to-print contracts, staff from the laboratory and the vendors worked toward transferring both design principles and practical details to an industrial framework for cost effective production. All magnets made thus far have been acceptable for use in RHIC

  9. Vertically aligned carbon nanotubes for microelectrode arrays applications.

    Science.gov (United States)

    Castro Smirnov, J R; Jover, Eric; Amade, Roger; Gabriel, Gemma; Villa, Rosa; Bertran, Enric

    2012-09-01

    In this work a methodology to fabricate carbon nanotube based electrodes using plasma enhanced chemical vapour deposition has been explored and defined. The final integrated microelectrode based devices should present specific properties that make them suitable for microelectrode arrays applications. The methodology studied has been focused on the preparation of highly regular and dense vertically aligned carbon nanotube (VACNT) mat compatible with the standard lithography used for microelectrode arrays technology.

  10. Modeling Heterogeneous Carbon Nanotube Networks for Photovoltaic Applications Using Silvaco Atlas Software

    OpenAIRE

    Garfrerick, Adam R.

    2012-01-01

    Recent developments in carbon nanotube technology have allowed for semi-transparent electrodes to be created which can possibly improve the efficiency of solar cells. A method for simulating the use of semi-transparent carbon nanotube networks as a charge collector for solar cells in Silvaco ATLAS software is presented in this thesis. Semi-transparent carbon nanotube networks allow for a greater area of charge collection on the surface of solar cells as well as a lower resistance path for cha...

  11. FERROMAGNETIC NANOTUBES IN PORES OF TRACK MEMBRANES FOR THE FLEXIBLE ELECTRONIC ELEMENTS

    Directory of Open Access Journals (Sweden)

    E. Yu. Kaniukov

    2017-01-01

    Full Text Available In the paper the template synthesis of ferromagnetic (Fe, Co, Ni nanotubes in the pores of track membranes were studied. The aim of this work was determination of nanotubes basic structural and magnetic parameters and demonstration of the possibility of application in the flexible electronics elements.By electrochemical deposition, ferromagnetic nanotubes with a diameter of 110 nm and an aspect ratio of 100 were formed in the pores of polyethylene terephthalate track membranes. The morphology of the obtained nanostructures were studied by scanning electron microscopy, the elemental composition was determined by the energy-dispersion analysis. Using the X-ray structural analysis, the main parameters of the crystal structure were established: lattice type, lattice parameter and average crystallite size. The magnetic properties were studied by the method of vibrational magnetometry.It was shown that in the selected conditions of synthesis without reference to the type of ferromagnetic metals nanotubes had the same dimensions – length, diameter and wall thickness. The produced nanotubes consisted of iron, cobalt and nickel, respectively without oxides impurities. Nanotubes had a polycrystalline structure of walls with a body-centered cubic (iron, face-centered cubic (cobalt and nickel crystal lattice. According to the main magnetic parameters, nanotubes belonged to a group of soft magnetic materials. Also, the presence of magnetic anisotropy, which is caused by the features of crystalline structure and shape of the nanostructures.Based on the analysis of structural and magnetic characteristics of ferromagnetic nanotubes which were synthesized in the pores of track membranes, were proposed the main principles of their using in the elements’ of flexible electronics constructing (magnetic field direction sensors and magnetic memory elements. 

  12. MAGNET

    CERN Multimedia

    Benoit Curé

    The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

  13. MAGNET

    CERN Multimedia

    B. Curé

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

  14. Spin transport in ferromagnetically contacted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.; Morgan, C.; Schneider, C.M. [Peter Gruenberg Institut, PGI-6, Forschungszentrum Juelich and JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany)

    2011-11-15

    We present magnetoresistance (MR) measurements on carbon nanotubes (CNTs) with different ferromagnetic leads. A sample with permalloy (Ni{sub 80}Fe{sub 20}) contacts shows the expected tunneling-type MR effect. Measurements on devices with CoPd contacts show a larger change of resistance with magnetic field. However, only minor loops are observed, which is explained with domain wall pinning. This is supported by magnetic force microscopy (MFM) measurements, which reveal a complicated bubble and stripe domain pattern. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Nanotube resonator devices

    Science.gov (United States)

    Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

    2014-05-06

    A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

  16. Beating liquid helium: the technologies of cryogen-free superconducting magnets

    Science.gov (United States)

    Burgoyne, John

    2015-03-01

    Cryogen-free superconducting magnets have been available now for almost 15 years, but have only become standard commercial products in more recent years. In this review we will consider the pros and cons of ``dry'' design including superconducting wire development and selection, thermal budgeting, and the alternative methods for achieving magnet cooling.

  17. Quantum oscillations and ferromagnetic hysteresis observed in iron filled multiwall carbon nanotubes.

    Science.gov (United States)

    Barzola-Quiquia, J; Klingner, N; Krüger, J; Molle, A; Esquinazi, P; Leonhardt, A; Martínez, M T

    2012-01-13

    We report on the electrical transport properties of single multiwall carbon nanotubes with and without an iron filling as a function of temperature and magnetic field. For the iron filled nanotubes the magnetoresistance shows a magnetic behavior induced by iron, which can be explained by taking into account a contribution of s-d hybridization. In particular, ferromagnetic-like hysteresis loops were observed up to 50 K for the iron filled multiwall carbon nanotubes. The magnetoresistance shows quantum interference phenomena such as universal conductance fluctuations and weak localization effects.

  18. Theoretical studies of the lithium atom on the silicon carbide nanotubes

    International Nuclear Information System (INIS)

    Yu, Guolong; Chen, Na; Wang, Feifei; Xie, Yiqun; Ye, Xiang; Gu, Xiao

    2014-01-01

    Based on density functional theory method, we have investigated structural, electronic, and magnetic properties of lithium (Li) atom adsorbed on silicon carbide (SiC) zigzag (9,0) and armchair (5,5) nanotubes. Effective adsorptions are found on both inner- and outer-side of the SiC nanotubes, with adsorption energies ranging from 1.03 to 1.71 eV. Interestingly, we have found that SiC nanotubes exhibit different behaviors with several Li adsorption sites. Li adsorptions on the s-Si and s-H sites of the outer surface and all the five sites of the inner surface in zigzag (9,0) nanotube emerge metallic features, whereas adsorptions on other sides of (9,0) and all sites of armchair (5,5) SiC nanotubes show semiconducting characters. The calculating results also indicate that lithium adsorptions on most sites of SiC nanotubes yield spontaneous magnetization, where net magnetic moment is 1 μ B . Additionally, spin density of states, spin density distribution, and charge density difference are also calculated to investigate the electronic and magnetic properties of SiC nanotubes induced by Li adsorption

  19. Magnets and magnetic materials

    International Nuclear Information System (INIS)

    Meuris, Ch.; Rifflet, J.M.

    2007-01-01

    The Large Hadron Collider (LHC), the world's largest highest-energy particle collider that the CERN plans to commission in 2008, gets a double boost from superconducting magnet technology. Superconducting magnets are first used to guide the particles scheduled for collision through the accelerator, and then to observe the events triggered by the collision inside giant detectors in a known magnetic field. Despite the installation's massive dimensions, all this is done with minimal expenditure of energy. (author)

  20. Moessbauer Study of Iron-Containing Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Marco, J. F.; Gancedo, J. R. [CSIC, Instituto de Quimica-Fisica ' Rocasolano' (Spain); Hernando, A.; Crespo, P.; Prados, C.; Gonzalez, J. M. [Instituto de Magnetismo Aplicado (Spain); Grobert, N.; Terrones, M.; Walton, D. R. M.; Kroto, H. W. [University of Sussex, Fullerene Science Centre, School of Chemistry, Physics and Environmental Science (United Kingdom)

    2002-03-15

    {sup 57}Fe transmission Moessbauer at temperatures between 18 and 298 K and magnetic measurements have been used to characterize Fe-filled carbon nanotubes which were prepared by pyrolisis of Ferrocene + C{sub 60} at atmospheric pressure under an Ar atmosphere at 1050{sup o}C. The Moessbauer data have shown that the Fe phases encapsulated within the carbon nanotubes are {alpha}-Fe, Fe{sub 3}C and {gamma}-Fe. The magnetic results are compatible with the Moessbauer data. Taken together the results allow us to propose a simple picture of the distribution of iron phases within the carbon nanotubes which would consist of an {alpha}-Fe core surrounded by an {gamma}-Fe shell, finally covered by an Fe{sub 3}C layer.

  1. Current technological advances in magnetic resonance with critical impact for clinical diagnosis and therapy.

    Science.gov (United States)

    Runge, Val M

    2013-12-01

    The last 5 years of technological advances with major impact on clinical magnetic resonance (MR) are discussed, with greater emphasis on those that are most recent. These developments have already had a critical positive effect on clinical diagnosis and therapy and presage continued rapid improvements for the next 5 years. This review begins with a discussion of 2 topics that encompass the breadth of MR, in terms of anatomic applications, contrast media, and MR angiography. Subsequently, innovations are discussed by anatomic category, picking the areas with the greatest development, starting with the brain, moving forward to the liver and kidney, and concluding with the musculoskeletal system, breast, and prostate. Two final topics are then considered, which will likely, with time, become independent major fields in their own right, interventional MR and MR positron emission tomography (PET).The next decade will bring a new generation of MR contrast media, with research focused on substantial improvements (>100-fold) in relaxivity (contrast effect), thus providing greater efficacy, safety, and tissue targeting. Magnetic resonance angiography will see major advances because of the use of compressed sensing, in terms of spatial and temporal resolution, with movement away from nondynamic imaging. The breadth of available techniques and tissue contrast has greatly expanded in brain imaging, benefiting both from the introduction of new basic categories of imaging techniques, such as readout-segmented echo planar imaging and 3D fast spin echo imaging with variable flip angles, and from new refinements specific to anatomic areas, such as double inversion recovery and MP2RAGE. Liver imaging has benefited from the development of techniques to easily and rapidly assess lipid, and will see, overall, a marked improvement in the next 5 years from new techniques on the verge of clinical introduction, such as controlled aliasing in parallel imaging results in higher acceleration

  2. 28 May 2010 - Japanese Ambassador H. Ueda visiting the LHC superconducting magnet test hall with CERN Technology Deputy Department Head L. Rossi.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    CERN-HI-1005088 02 Japanese Ambassador H. Ueda (right) visiting the LHC superconducting magnet test hall with Technology Deputy Department Head L. Rossi(left). H. Ueda is accompanied by KEK and ATLAS Collaboration T. Kondo (centre).

  3. Development of ultra-short high voltage pulse technology using magnetic pulse compression

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Byung Heon; Kim, S. G.; Nam, S. M.; Lee, B. C.; Lee, S. M.; Jeong, Y. U.; Cho, S. O.; Jin, J. T.; Choi, H. L

    1998-01-01

    The control circuit for high voltage switches, the saturable inductor for magnetic assist, and the magnetic pulse compression circuit were designed, constructed, and tested. The core materials of saturable inductors in magnetic pulse compression circuit were amorphous metal and ferrite and total compression stages were 3. By the test, in high repetition rate, high pulse compression were certified. As a result of this test, it became possible to increase life-time of thyratrons and to replace thyratrons by solid-state semiconductor switches. (author). 16 refs., 16 tabs.

  4. Development of ultra-short high voltage pulse technology using magnetic pulse compression

    International Nuclear Information System (INIS)

    Cha, Byung Heon; Kim, S. G.; Nam, S. M.; Lee, B. C.; Lee, S. M.; Jeong, Y. U.; Cho, S. O.; Jin, J. T.; Choi, H. L.

    1998-01-01

    The control circuit for high voltage switches, the saturable inductor for magnetic assist, and the magnetic pulse compression circuit were designed, constructed, and tested. The core materials of saturable inductors in magnetic pulse compression circuit were amorphous metal and ferrite and total compression stages were 3. By the test, in high repetition rate, high pulse compression were certified. As a result of this test, it became possible to increase life-time of thyratrons and to replace thyratrons by solid-state semiconductor switches. (author). 16 refs., 16 tabs

  5. Surface magnetic structures in amorphous ferromagnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Usov, N.A., E-mail: usov@obninsk.ru [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Serebryakova, O.N.; Gudoshnikov, S.A. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Tarasov, V.P. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation)

    2017-05-01

    The spatial period of magnetization perturbations that occur near the surface of magnetic nanotube or nanowire under the influence of surface magnetic anisotropy is determined by means of numerical simulation as a function of the sample geometry and material parameters. The surface magnetization distribution obtained is then used to estimate the period of the surface magnetic texture in amorphous microwire of several micrometers in diameter by means of appropriate variational procedure. The period of the surface magnetic texture in amorphous microwire is found to be significantly smaller than the wire diameter. - Highlights: • Magnetic structure may arise near the magnetic nanotube surface under the influence of surface magnetic anisotropy. • The period of the surface magnetization pattern is calculated as a function of the sample geometry. • Similar magnetic structure may exist in amorphous microwire of several micrometers in diameter. • The period of the surface magnetic structure in amorphous wire is found to be significantly smaller than the wire diameter.

  6. Transparent conducting oxide nanotubes

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

    2014-09-01

    Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 × 10-4 Ωcm at T = 300 K (compared to 6.5 × 10-1 Ωcm for nominally undoped nanotubes) to 2.2 × 10-4 Ωcm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

  7. Conducting carbonized polyaniline nanotubes

    International Nuclear Information System (INIS)

    Mentus, Slavko; Ciric-Marjanovic, Gordana; Trchova, Miroslava; Stejskal, Jaroslav

    2009-01-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min -1 up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 μm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 μm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm -1 , increased to 0.7 S cm -1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  8. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  9. Integrated Approach to Dense Magnetized Plasmas Applications in Nuclear Fusion Technology. Report of a Coordinated Research Project 2007-2011

    International Nuclear Information System (INIS)

    2013-04-01

    Through its coordinated research activities, the IAEA promotes the development and application of nuclear technologies in Member States. The scientific and technical knowledge required for the construction and operation of large nuclear fusion research facilities, including ITER and the Laser Megajoule in France, and the Z machine and the National Ignition Facility in the United States of America, necessitates several accompanying research and development programmes in physics and technology. This is particularly true in the areas of materials science and fusion technology. Hence, the long standing IAEA effort to conduct coordinated research projects (CRPs) in these areas is aimed at: (i) the development of appropriate technical tools to investigate the issue of materials damage and degradation in a fusion plasma environment; and (ii) the emergence of a knowledge based understanding of the various processes underlying materials damage and degradation, thereby leading to the identification of suitable candidate materials fulfilling the stringent requirements of a fusion environment in any next step facility. Dense magnetized plasma (DMP) devices serve as a first test bench for testing of fusion relevant plasma facing materials, diagnostic development and calibration, technologies and scaling to conceptual principles of larger devices while sophisticated testing facilities such as the International Fusion Materials Irradiation Facility (IFMIF) are being designed. The CRP on Integrated Approach to Dense Magnetized Plasmas Applications in Nuclear Fusion Technology described herein was initiated in 2007 with the participation of 12 research institutions in 8 Member States and was concluded in 2011. It was designed with specific research objectives falling into two main categories: support to mainstream fusion research and development of DMP technology. This publication is a compilation of the individual reports submitted by the 12 CRP participants. These reports discuss

  10. Magnetic

    Science.gov (United States)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  11. MAGNET

    CERN Multimedia

    Benoit Curé

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

  12. MAGNET

    CERN Document Server

    B. Curé

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

  13. MAGNET

    CERN Multimedia

    Benoit Curé

    2013-01-01

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

  14. Ultra-high field NMR and MRI - the role of magnet technology to increase sensitivity and specificity

    Science.gov (United States)

    Moser, Ewald; Laistler, Elmar; Schmitt, Franz; Kontaxis, Georg

    2017-08-01

    "History, of course, is difficult to write, if for no other reason, than that it has so many players and so many authors." - P. J. Keating (former Australian Prime Minister) Starting with post-war developments in nuclear magnetic resonance (NMR) a race for stronger and stronger magnetic fields has begun in the 1950s to overcome the inherently low sensitivity of this promising method. Further challenges were larger magnet bores to accommodate small animals and eventually humans. Initially, resistive electromagnets with small pole distances, or sample volumes, and field strengths up to 2.35 T (or 100 MHz 1H frequency) were used in applications in physics, chemistry, and material science. This was followed by stronger and more stable (NbTi based) superconducting magnet technology typically implemented first for small-bore systems in analytical chemistry, biochemistry and structural biology, and eventually allowing larger horizontal-bore magnets with diameters large enough to fit small laboratory animals. By the end of the 1970s, first low-field resistive magnets big enough to accommodate humans were developed and superconducting whole-body systems followed. Currently, cutting-edge analytical NMR systems are available at proton frequencies up to 1 GHz (23.5 T) based on Nb3Sn at 1.9 K. A new 1.2 GHz system (28 T) at 1.9 K, operating in persistent mode but using a combination of low and high temperature multi-filament superconductors is to be released. Preclinical instruments range from small-bore animal systems with typically 600 - 800 MHz (14.1 - 18.8 T) up to 900 MHz (21 T) at 1.9 K. Human whole-body MRI systems currently operate up to 10.5 T. Hybrid combined superconducting and resistive electromagnets with even higher field strength of 45 T dc and 100 T pulsed, are available for material research, of course with smaller free bore diameters. This rather costly development towards higher and higher field strength is a consequence of the inherently low and, thus

  15. Application of Java Technology to Simulation of Transient Effects in Accelerator Magnets

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Superconducting magnets are one of the key building blocks of modern high-energy particle accelerators. Operating at extremely low temperatures (1.9 K), superconducting magnets produce high magnetic field needed to control the trajectory of beams travelling at nearly the speed of light. With high performance comes considerable complexity represented by several coupled physical domains characterized by multi-rate and multi-scale behaviour. The full exploitation of the LHC, as well as the design of its upgrades and future accelerators calls for more accurate simulations. With such a long-term vision in mind, the STEAM (Simulation of Transient Effects in Accelerator Magnets) project has been establish and is based on two pillars: (i) models developed with optimised solvers for particular sub-problems, (ii) coupling interfaces allowing to exchange information between the models. In order to tackle these challenges and develop a maintainable and extendable simulation framework, a team of developers implemented a ...

  16. Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography.

    Science.gov (United States)

    Attenberger, Ulrike I; Morelli, John; Budjan, Johannes; Henzler, Thomas; Sourbron, Steven; Bock, Michael; Riffel, Philipp; Hernando, Diego; Ong, Melissa M; Schoenberg, Stefan O

    2015-09-01

    Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

  17. Selective growth of carbon nanotube on silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZOU Xiao-ping; H. ABE; T. SHIMIZU; A. ANDO; H. TOKUMOT; ZHU Shen-ming; ZHOU Hao-shen

    2006-01-01

    The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies,and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

  18. Modelling the relative stability of carbon nanotubes exposed to environmental adsorbates and air

    International Nuclear Information System (INIS)

    Barnard, Amanda S

    2009-01-01

    In parallel with the development of technological applications for carbon nanotubes, issues related to toxicology and environmental impact are also under increased scrutiny. It is clear from the available literature that the integrity of future carbon nanotube-based devices, our ability to anticipate failure of these devices, and our ability to manage the toxicological and environmental impacts require a detailed understanding of the stability of pure and functionalized carbon nanotubes under a full range of environmental conditions. Motivated by this endeavour, the present study uses a general thermodynamic model to predict the relative stability of carbon nanotubes exposed to a variety of atmospheric adsorbates, and uses them to examine the stability of nanotubes in air, as a function of the relative humidity. In general the results indicate that the adsorption of a sparse coverage of air is thermodynamically favoured, depending on the humidity, and the stability of small diameter nanotubes may be improved by exposure to humid air.

  19. Characterisation of a new carbon nanotube detector coating for solar absolute radiometers

    Science.gov (United States)

    Remesal Oliva, A.; Finsterle, W.; Walter, B.; Schmutz, W.

    2018-02-01

    A new sprayable carbon nanotube coating for bolometric detectors aims to increase the absorptance compared to regular space qualified black paints. In collaboration with the National Institute of Standards and Technology (NIST), we have characterized the optical properties and mechanical and thermal stability of the carbon nanotube coating inside conical shaped cavity detectors.

  20. Influence of the concentration of carbon nanotubes on electrical ...

    Indian Academy of Sciences (India)

    Influence of the concentration of carbon nanotubes on electrical conductivity of magnetically aligned MWCNT–polypyrrole composites. KAVEH KAZEMIKIA1,∗, FAHIMEH BONABI2, ALI ASADPOORCHALLO3 and. MAJID SHOKRZADEH4. 1Department of Electrical and Computer Engineering, Islamic Azad University, Bonab ...

  1. Plasma excitations in a single-walled carbon nanotube

    Indian Academy of Sciences (India)

    The effect of different uniform transverse external magnetic fields in plasma frequency when propagated parallel to the surface of the single-walled metallic carbon nanotubes is studied. The classical electrodynamics as well as Maxwell's equations are used in the calculations. Equations are developed for both short- and ...

  2. Bends in nanotubes allow electric spin control and coupling

    DEFF Research Database (Denmark)

    Flensberg, Karsten; Marcus, Charles Masamed

    2010-01-01

    We investigate combined effects of spin-orbit coupling and magnetic field in carbon nanotubes containing one or more bends along their length. We show how bends can be used to provide electrical control of confined spins, while spins confined in straight segments remain insensitive to electric...

  3. Carbon nanotube junctions and devices

    NARCIS (Netherlands)

    Postma, H.W.Ch.

    2001-01-01

    In this thesis Postma presents transport experiments performed on individual single-wall carbon nanotubes. Carbon nanotubes are molecules entirely made of carbon atoms. The electronic properties are determined by the exact symmetry of the nanotube lattice, resulting in either metallic or

  4. Technological and economical analysis of salient pole and permanent magnet synchronous machines designed for wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Guendogdu, Tayfun, E-mail: tgundogdu@itu.edu.tr [Istanbul Technical University, Department of Electrical Engineering, Ayazaga Campus, 34469 Maslak/Istanbul (Turkey); Koemuergoez, Gueven, E-mail: komurgoz@itu.edu.tr [Istanbul Technical University, Department of Electrical Engineering, Ayazaga Campus, 34469 Maslak/Istanbul (Turkey)

    2012-08-15

    Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality. The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted. - Highlights: Black-Right-Pointing-Pointer Importance of the design of electrical machines and the determination of criteria are emphasized. Black-Right-Pointing-Pointer Machines were investigated in terms of

  5. Technological and economical analysis of salient pole and permanent magnet synchronous machines designed for wind turbines

    International Nuclear Information System (INIS)

    Gündoğdu, Tayfun; Kömürgöz, Güven

    2012-01-01

    Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality. The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted. - Highlights: ► Importance of the design of electrical machines and the determination of criteria are emphasized. ► Machines were investigated in terms of efficiency, weight and maintenance requirements. ► An

  6. Synthesis of carbon nanotubes and nanotube forests on copper catalyst

    International Nuclear Information System (INIS)

    Kruszka, Bartosz; Terzyk, Artur P; Wiśniewski, Marek; Gauden, Piotr A; Szybowicz, Mirosław

    2014-01-01

    The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices. (paper)

  7. Electric and Magnetic Fields (EMF) RAPID Program Engineering Project 8: FINAL REPORT, Evaluation of Field Reduction Technologies, Volume 1 (Report) and Volume 2 (Appendices)

    Energy Technology Data Exchange (ETDEWEB)

    Commonwealth Associates, Inc.; IIT Research Institute

    1997-08-01

    This draft report consists of two volumes. Volume 1, the main body, contains an introducto~ sectionj an overview of magnetic fields sectio~ and field reduction technology evaluation section. Magnetic field reduction methods are evalpated for transmission lines, distribution Iines,sulxtations, building wiring applkmd machinery, and transportation systems. The evaluation considers effectiveness, co% and other ftiors. Volume 2 contains five appendices, Append~ A presents magnetic field shielding information. Appendices B and C present design assumptions and magnetic field plots for transmission and distribution lines, respectively. Appendices D and E present cost estimate details for transmission and distribution limes, respectively.

  8. PCR-free detection of genetically modified organisms using magnetic capture technology and fluorescence cross-correlation spectroscopy.

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhou

    2009-11-01

    Full Text Available The safety of genetically modified organisms (GMOs has attracted much attention recently. Polymerase chain reaction (PCR amplification is a common method used in the identification of GMOs. However, a major disadvantage of PCR is the potential amplification of non-target DNA, causing false-positive identification. Thus, there remains a need for a simple, reliable and ultrasensitive method to identify and quantify GMO in crops. This report is to introduce a magnetic bead-based PCR-free method for rapid detection of GMOs using dual-color fluorescence cross-correlation spectroscopy (FCCS. The cauliflower mosaic virus 35S (CaMV35S promoter commonly used in transgenic products was targeted. CaMV35S target was captured by a biotin-labeled nucleic acid probe and then purified using streptavidin-coated magnetic beads through biotin-streptavidin linkage. The purified target DNA fragment was hybridized with two nucleic acid probes labeled respectively by Rhodamine Green and Cy5 dyes. Finally, FCCS was used to detect and quantify the target DNA fragment through simultaneously detecting the fluorescence emissions from the two dyes. In our study, GMOs in genetically engineered soybeans and tomatoes were detected, using the magnetic bead-based PCR-free FCCS method. A detection limit of 50 pM GMOs target was achieved and PCR-free detection of GMOs from 5 microg genomic DNA with magnetic capture technology was accomplished. Also, the accuracy of GMO determination by the FCCS method is verified by spectrophotometry at 260 nm using PCR amplified target DNA fragment from GM tomato. The new method is rapid and effective as demonstrated in our experiments and can be easily extended to high-throughput and automatic screening format. We believe that the new magnetic bead-assisted FCCS detection technique will be a useful tool for PCR-free GMOs identification and other specific nucleic acids.

  9. Synthesis and characterization of magnetic cobalt ferrite nanoparticles covered with 3-aminopropyltriethoxysilane for use as hybrid material in nano technology

    International Nuclear Information System (INIS)

    Camilo, Ruth Luqueze

    2006-01-01

    Nowadays with the appear of nano science and nano technology, magnetic nanoparticles have been finding a variety of applications in the fields of biomedicine, diagnosis, molecular biology, biochemistry, catalysis, etc. The magnetic functionalized nanoparticles are constituted of a magnetic nucleus, involved by a polymeric layer with active sites, which ones could anchor metals or selective organic compounds. These nanoparticles are considered organic inorganic hybrid materials and have great interest as materials for commercial applications due to the specific properties. Among the important applications it can be mentioned: magneto hyperthermia treatment, drugs delivery in specific local of the body, molecular recognition, biosensors, enhancement of nuclear magnetic resonance images quality, etc. This work was developed in two parts: 1) the synthesis of the nucleus composed by superparamagnetic nanoparticles of cobalt ferrite and, 2) the recovering of nucleus by a polymeric bifunctional 3-aminopropyltriethoxysilane. The parameters studied in the first part of the research were: pH, hydroxide molar concentration, hydroxide type, reagent order of addition, reagent way of addition, speed of shake, metals initial concentrations, molar fraction of cobalt and thermal treatment. In the second part it was studied: pH, temperature, catalyst type, catalyst concentration, time of reaction, relation ratios of H 2 O/silane, type of medium and the efficiency of the recovering regarding to pH. The products obtained were characterized using the following techniques X-ray powder diffraction (DRX), transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), spectroscopy of scatterbrained energy spectroscopy (DES), atomic emission spectroscopy (ICP-AES), thermogravimetric analysis (TGA/DTGA), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and magnetization curves (VSM). (author)

  10. Review of core technologies for development of 2G HTS NMR/MRI magnet: A status report of progress in Korea University

    Directory of Open Access Journals (Sweden)

    J.B. Song

    Full Text Available In this paper, we briefly review our recent progress on development of core technologies for 2G HTS NMR/MRI magnets at Korea University. To outperform the current state-of-art NMR/MRI magnet systems, we have developed the following technologies: 1 a REBCO-REBCO superconducting joint for operation of persistent current mode; 2 partial and grease-insulation winding techniques for self-protection of the HTS magnets; 3 pre-shimming to reduce the screening-current-induced-field; and 4 optimization of multi-width winding to minimize conductor consumption and volume of the HTS magnets. The test results demonstrated the feasibility of employing the developed techniques to achieve ultra-high-field and LHe-free 2G NMR/MRI magnets possessing self-protecting feature.

  11. Electron diffraction from carbon nanotubes

    International Nuclear Information System (INIS)

    Qin, L-C

    2006-01-01

    The properties of a carbon nanotube are dependent on its atomic structure. The atomic structure of a carbon nanotube can be defined by specifying its chiral indices (u, v), that specify its perimeter vector (chiral vector), with which the diameter and helicity are also determined. The fine electron beam available in a modern transmission electron microscope (TEM) offers a unique probe to reveal the atomic structure of individual nanotubes. This review covers two aspects related to the use of the electron probe in the TEM for the study of carbon nanotubes: (a) to understand the electron diffraction phenomena for inter-pretation of the electron diffraction patterns of carbon nanotubes and (b) to obtain the chiral indices (u, v), of the carbon nanotubes from the electron diffraction patterns. For a nanotube of a given structure, the electron scattering amplitude from the carbon nanotube is first described analytically in closed form using the helical diffraction theory. From a known structure as given by the chiral indices (u, v), its electron diffraction pattern can be calculated and understood. The reverse problem, i.e. assignment of the chiral indices from an electron diffraction pattern of a carbon nanotube, is approached from the relationship between the electron scattering intensity distribution and the chiral indices (u, v). We show that electron diffraction patterns can provide an accurate and unambiguous assignment of the chiral indices of carbon nanotubes. The chiral indices (u, v) can be read indiscriminately with a high accuracy from the intensity distribution on the principal layer lines in an electron diffraction pattern. The symmetry properties of electron diffraction from carbon nanotubes and the electron diffraction from deformed carbon nanotubes are also discussed in detail. It is shown that 2mm symmetry is always preserved for single-walled carbon nanotubes, but it can break down for multiwalled carbon nanotubes under some special circumstances

  12. Modifying the electronic and optical properties of carbon nanotubes

    Science.gov (United States)

    Kinder, Jesse M.

    The intrinsic electronic and optical properties of carbon nanotubes make them promising candidates for circuit elements and LEDs in nanoscale devices. However, applied fields and interactions with the environment can modify these intrinsic properties. This dissertation is a theoretical study of perturbations to an ideal carbon nanotube. It illustrates how transport and optical properties of carbon nanotubes can be adversely affected or intentionally modified by the local environment. The dissertation is divided into three parts. Part I analyzes the effect of a transverse electric field on the single-electron energy spectrum of semiconducting carbon nanotubes. Part II analyzes the effect of the local environment on selection rules and decay pathways relevant to dark excitons. Part III is a series of 26 appendices. Two different models for a transverse electric field are introduced in Part I. The first is a uniform field perpendicular to the nanotube axis. This model suggests the field has little effect on the band gap until it exceeds a critical value that can be tuned with strain or a magnetic field. The second model is a transverse field localized to a small region along the nanotube axis. The field creates a pair of exponentially localized bound states but has no effect on the band gap for particle transport. Part II explores the physics of dark excitons in carbon nanotubes. Two model calculations illustrate the effect of the local environment on allowed optical transitions and nonradiative recombination pathways. The first model illustrates the role of inversion symmetry in the optical spectrum. Broken inversion symmetry may explain low-lying peaks in the exciton spectrum of boron nitride nanotubes and localized photoemission around impurities and interfaces in carbon nanotubes. The second model in Part II suggests that free charge carriers can mediate an efficient nonradiative decay process for dark excitons in carbon nanotubes. The appendices in Part III

  13. Adhered Supported Carbon Nanotubes

    International Nuclear Information System (INIS)

    Johnson, Dale F.; Craft, Benjamin J.; Jaffe, Stephen M.

    2001-01-01

    Carbon nanotubes (NTs) in excess of 200 μm long are grown by catalytic pyrolysis of hydrocarbon vapors. The nanotubes grow continuously without the typical extinction due to catalyst encapsulation. A woven metal mesh supports the nanotubes creating a metal supported nanotube (MSNT) structure. The 140 μm wide mesh openings are completely filled by 70 nm diameter multiwalled nanotubes (MWNTs). The MWNTs are straight, uniform and highly crystalline. Their wall thickness is about 10 nm (30 graphite layers). The adherent NTs are not removed from the support in a Scotch tape pull test. A 12.5 cm 2 capacitor made from two MSNT structures immersed in 1 M KCl has a capacitance of 0.35 F and an equivalent series resistance of 0.18 Ω. Water flows through the MSNT at a flow velocity of 1 cm/min with a pressure drop of 15 inches of water. With the support removed, the MWNTs naturally form a carbon nanocomposite (CNC) paper with a specific area of 80 m 2 /gm, a bulk density of 0.21 g/cm 3 , an open pore fraction of 0.81, and a resistivity of 0.16 Ω-cm

  14. Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.

    Science.gov (United States)

    Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk

    2015-03-01

    Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Magnetic fusion energy materials technology program, annual progress report for period ending June 30, 1976

    International Nuclear Information System (INIS)

    Scott, J.L.

    1976-09-01

    Activities in research programs are reported on materials for use in thermonuclear reactor development. Information and data are included on radiation effects on stainless steel 316, nickel-base alloys, molybdenum-base alloys, vanadium alloys, and SAP. Results of compatibility studies involving iron-base alloys and lithium are also included along with research results on magnet development

  16. Magnetic fusion energy materials technology program, annual progress report for period ending June 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Scott, J.L. (comp.)

    1976-09-01

    Activities in research programs are reported on materials for use in thermonuclear reactor development. Information and data are included on radiation effects on stainless steel 316, nickel-base alloys, molybdenum-base alloys, vanadium alloys, and SAP. Results of compatibility studies involving iron-base alloys and lithium are also included along with research results on magnet development. (JRD)

  17. Soldering of Nanotubes onto Microelectrodes

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing sold...... bonds were consistently found to be mechanically stronger than the carbon nanotubes.......Suspended bridges of individual multiwalled carbon nanotubes were fabricated inside a scanning electron microscope by soldering the nanotube onto microelectrodes with highly conducting gold-carbon material. By the decomposition of organometallic vapor with the electron beam, metal-containing solder...... bonds were formed at the intersection of the nanotube and the electrodes. Current-voltage curves indicated metallic conduction of the nanotubes, with resistances in the range of 9-29 kOmega. Bridges made entirely of the soldering material exhibited resistances on the order of 100 Omega, and the solder...

  18. Development of high-resolution two-dimensional magnetic field measurement system by use of printed-circuit technology

    Science.gov (United States)

    Akimitsu, Moe; Qinghong, Cao; Sawada, Asuka; Hatano, Hironori; Tanabe, Hiroshi; Ono, Yasushi; TS-Group Team

    2017-10-01

    We have developed a new-types of high-resolution magnetic probe array for our new magnetic reconnection experiments: TS-3U (ST, FRC: R =0.2m, 2017-) and TS-4U (ST, FRC: R =0.5m, 2018-), using the advanced printed-circuit technology. They are equipped with all three-components of magnetic pick-up coils whose size is 1-5mm x 3mm. Each coil is composed of two-sided coil pattern with line width of 0.05mm. We can install two or three printed arrays in a single glass (ceramic) tube for two or three component measurements. Based on this new probe technique, we started high-resolution and high-accuracy measurement of the current sheet thickness and studied its plasma parameter dependence. We found that the thickness of current sheet increases inversely with the guide toroidal field. It is probably determined by the ion gyroradius in agreement with the particle simulation by Horiuchi etc. While the reconnection speed is steady under low guide field condition, it is observed to oscillate in the specific range of guide field, suggesting transition from the quasi-steady reconnection to the intermittent reconnection. Cause and mechanism for intermittent reconnection will be discussed using the current sheet dissipation and dynamic balance between plasma inflow and outflow. This work supported by JSPS KAKENHI Grant Numbers 15H05750, 15K14279 and 17H04863.

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

    Science.gov (United States)

    Xue, Mianqiang; Li, Jia; Xu, Zhenming

    2012-03-06

    Metal-plated plastics (MPP), which are important from the standpoint of aesthetics or even performance, are increasingly employed in a wide variety of situations in the automotive industry. Serious environmental problems will be caused if they are not treated appropriately. Therefore, recycling of MPP is an important subject not only for resource recycling but also for environmental protection. This work represents a novel attempt to deal with the MPP. A self-designed hammer crusher was used to liberate coatings from the plastic substrate. The size distribution of particles was analyzed and described by the Rosin-Rammler function model. The optimum retaining time of materials in the crusher is 3 min. By this time, the liberation rate of the materials can reach 87.3%. When the density of the suspension is 31,250 g/m(3), the performance of liberation is the best. Two-step magnetic separation was adopted to avoid excessive crushing and to guarantee the quality of products. Concerning both the separation efficiency and grade of products, the optimum rotational speed of the magnetic separator is 50-70 rpm. On the basis of the above studies about the liberating and separating behavior of the materials, a continuous recycling system (the technology of crush-magnetic separation) is developed. This recycling system provides a feasible method for recycling MPP efficiently, economically, and environmentally.

  20. EB treatment of carbon nanotube-reinforced polymer composites

    International Nuclear Information System (INIS)

    Szebenyi, G.; Romhany, G.; Czvikovszky, T.; Vajna, B.

    2011-01-01

    Complete text of publication follows. A small amount - less than 0.5% - carbon nanotube reinforcement may improve significantly the mechanical properties of epoxy based composite materials. The basic technical problem is on one side the dispersion of the nanotubes into the viscous matrix resin. Namely the fine, powder-like - less than 100 nanometer diameter - nanotubes are prone to form aggregates. On the other side, the good connection between the nanofiber and matrix, - which is determining the success of the reinforcement, - requires some efficient adhesion promoting treatment. After an elaborate masterbatch mixing technology we applied Electron Beam treatment of epoxy-matrix polymer composites containing carbon nanotubes in presence of vinylester resins. The Raman spectra of vinylester-epoxy mixtures treated by an 8 MeV EB showed the advantage of the electron treatment. Even in the case of partially immiscible epoxy and vinylester resins, the anchorage of carbon nanotubes reflects improvement if a reasonable 25 kGy EB dose is applied. Atomic Force Microscopy as well as mechanical tests on flexural and impact properties confirm the benefits of EB treatment. Simultaneous application of multiwall carbon nanotubes and 'conventional' carbon fibers as reinforcement in vinylester modified epoxies results in new types of hybrid nanocomposites as engineering materials. The bending- and interlaminar properties of such hybrid systems showed the beneficial effect of the EB treatment. Acknowledgement: This work has been supported by the New Hungary Development Plan (Project ID: TAMOP-4.2.1/B-09/1/KMR-2010-0002).

  1. Solar energy harvesting by magnetic-semiconductor nanoheterostructure in water treatment technology.

    Science.gov (United States)

    Mahmoodi, Vahid; Bastami, Tahereh Rohani; Ahmadpour, Ali

    2018-03-01

    Photocatalytic degradation of toxic organic pollutants in the wastewater using dispersed semiconductor nanophotocatalysts has a number of advantages such as high activity, cost effectiveness, and utilization of free solar energy. However, it is difficult to recover and recycle nanophotocatalysts since the fine dispersed nanoparticles are easily suspended in waters. Furthermore, a large amount of photocatalysts will lead to color contamination. Thus, it is necessary to prepare photocatalysts with easy separation for the reusable application. To take advantage of high photocatalysis activity and reusability, magnetic photocatalysts with separation function were utilized. In this review, the photocatalytic principle, structure, and application of the magnetic-semiconductor nanoheterostructure photocatalysts under solar light are evaluated. Graphical abstract ᅟ.

  2. Development of superconductor application technology - Flywheel energy storage system using superconducting magnetic bearing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Soo Hun; Oh, Hueng Kuk; Yun, Keyng Reyl; Lee, Jeung Kun [Ahju University, Suwon (Korea, Republic of)

    1996-06-01

    Electricity must be used simultaneously with its generation. Existing storage methods either are dependent on special geography, are too expensive,= or are too inefficient. Electricity demand changes by as much as 30% over a 12-hour period and result in significant costs for utilities as power output get adjusted to meet these changes. The purpose of HTS FES is to store unused nighttime electricity until it is needed during the daytime. If every element of a rotating flywheel is stressed to a prescribed allowable value, the flywheel material will clearly be used in most efficient manner. The uniformlt stressed flywheel is about 25% stronger than a flat disk. The gap between superconductor and permanent magnet was 1.85 mm, and using bearing connector with the values, joining superconductor to permanent magnet Using bolt connector, joining permanent magnet to flywheel. Joined system is excited by exciting function that magnitude is 1, range is 0 up to 4000 HZ. 3 rd and 4 th natural frequency, 1857 HZ and 2340 HZ, in X direction and 2 nd natural frequency, 28.57 HZ, are avoided to prevent resonance. 15 refs., 11 tabs., 53 figs. (author)

  3. Carbon-Containing Waste of Coal Enterprises in Magnetic Sorbents Technology

    Science.gov (United States)

    Kvashevaya, Ekaterina; Ushakova, Elena; Ushakov, Andrey

    2017-11-01

    The article shows the issues state of coal-mining enterprises carbonaceous wastes utilization, including by obtaining oil-sorbent. The characteristics of the feedstock are presented; experiment methods of obtaining a binder based on the livestock enterprises waste, of forming binder with filler (sawdust, coal waste); of pyrogenetic processing to obtain a sorbent are described. Possible options for the introduction of magnetite (a magnetic component) in the composition of the oil sorbent are considered: on the surface, in the volume of the granule and the magnetite core. In the course of the work it was found that the optimum content of coal dust in the sorbent granules is 75% by weight, and the most effective way of obtaining the magnetic sorbent is to apply the carbon material directly to the "core" of magnetite. However, in this case, the problem of finding an effective binder for magnetite arises. The option of applying magnetite on the surface of a carbon sorbent is not effective. Thus, at present, we use a mixture of coal waste, which binds to the uniform distribution of magnetite in the volume. The developed magnetic sorbents can be used in various weather conditions, including strong winds and icing of water bodies, as well as for small and medium currents.

  4. Carbon Nanotubes Filled with Ferromagnetic Materials

    Directory of Open Access Journals (Sweden)

    Albrecht Leonhardt

    2010-08-01

    Full Text Available Carbon nanotubes (CNT filled with ferromagnetic metals like iron, cobalt or nickel are new and very interesting nanostructured materials with a number of unique properties. In this paper we give an overview about different chemical vapor deposition (CVD methods for their synthesis and discuss the influence of selected growth parameters. In addition we evaluate possible growth mechanisms involved in their formation. Moreover we show their identified structural and magnetic properties. On the basis of these properties we present different application possibilities. Some selected examples reveal the high potential of these materials in the field of medicine and nanotechnology.

  5. Carbon Nanotubes Filled with Ferromagnetic Materials

    Science.gov (United States)

    Weissker, Uhland; Hampel, Silke; Leonhardt, Albrecht; Büchner, Bernd

    2010-01-01

    Carbon nanotubes (CNT) filled with ferromagnetic metals like iron, cobalt or nickel are new and very interesting nanostructured materials with a number of unique properties. In this paper we give an overview about different chemical vapor deposition (CVD) methods for their synthesis and discuss the influence of selected growth parameters. In addition we evaluate possible growth mechanisms involved in their formation. Moreover we show their identified structural and magnetic properties. On the basis of these properties we present different application possibilities. Some selected examples reveal the high potential of these materials in the field of medicine and nanotechnology. PMID:28883334

  6. Magnetoreresistance of carbon nanotube-polypyrrole composite yarns

    Science.gov (United States)

    Ghanbari, R.; Ghorbani, S. R.; Arabi, H.; Foroughi, J.

    2018-05-01

    Three types of samples, carbon nanotube yarn and carbon nanotube-polypyrrole composite yarns had been investigated by measurement of the electrical conductivity as a function of temperature and magnetic field. The conductivity was well explained by 3D Mott variable range hopping (VRH) law at T < 100 K. Both positive and negative magnetoresistance (MR) were observed by increasing magnetic field. The MR data were analyzed based a theoretical model. A quadratic positive and negative MR was observed for three samples. It was found that the localization length decreases with applied magnetic field while the density of states increases. The increasing of the density of states induces increasing the number of available energy states for hopping. Thus the electron hopping probability increases in between sites with the shorter distance that results to small the average hopping length.

  7. Magnetoresistive phenomena in an Fe-filled carbon nanotube/elastomer composite

    International Nuclear Information System (INIS)

    Hudziak, S; Baxendale, M; Darfeuille, A; Zhang, R; Peijs, T; Mountjoy, G; Bertoni, G

    2010-01-01

    DC magnetoresistive effects were observed in above-percolation-threshold loaded Fe-filled carbon nanotube/polyurethane-urea composite samples. A phenomenological model is derived from interpretation of resistance relaxation for a range of axial strains. The large instantaneous magnetoresistance of + 90% observed at low axial strain was a result of conduction pathway breaking caused by preferential orientation of the conducting nanotubes perpendicular to the axial current flow: a result of the magnetic torque experienced by the ferromagnetic nanotube core. At large strain the observed large instantaneous change in resistance of - 90% resulted from voltage-driven relaxation in the conducting nanotube network. At high axial strain the competition between voltage-driven relaxation and a magnetic torque gave rise to an oscillatory component of resistance relaxation.

  8. Magnetoresistive phenomena in an Fe-filled carbon nanotube/elastomer composite.

    Science.gov (United States)

    Hudziak, S; Darfeuille, A; Zhang, R; Peijs, T; Mountjoy, G; Bertoni, G; Baxendale, M

    2010-03-26

    DC magnetoresistive effects were observed in above-percolation-threshold loaded Fe-filled carbon nanotube/polyurethane-urea composite samples. A phenomenological model is derived from interpretation of resistance relaxation for a range of axial strains. The large instantaneous magnetoresistance of + 90% observed at low axial strain was a result of conduction pathway breaking caused by preferential orientation of the conducting nanotubes perpendicular to the axial current flow: a result of the magnetic torque experienced by the ferromagnetic nanotube core. At large strain the observed large instantaneous change in resistance of - 90% resulted from voltage-driven relaxation in the conducting nanotube network. At high axial strain the competition between voltage-driven relaxation and a magnetic torque gave rise to an oscillatory component of resistance relaxation.

  9. Experimental Nanofluidics in an individual Nanotube

    Science.gov (United States)

    Siria, Alessandro; Poncharal, Philippe; Biance, Anne Laure; Fulcrand, Remy; Purcell, Stephen; Bocquet, Lyderic

    2012-11-01

    Building new devices that benefit from the strange transport behavior of fluids at nanoscales is an open and worthy challenge that may lead to new scientific and technological paradigms. We present here a new class of nanofluidic device, made of individual Boron-Nitride (BN) nanotube inserted in a pierced membrane and connecting two macroscopic reservoirs. We explore fluidic transport inside a single BN nanotube under electric fields, pressure drops, chemical gradients, and combinations of these. We show that in this transmembrane geometry, the pressure-driven streaming current is voltage gated, with an apparent electro-osmotic zeta potential raising up to one volt. Further, we measured the current induced by ion concentration gradients and show its dependency on the surface charge.

  10. Continuous carbon nanotube reinforced composites.

    Science.gov (United States)

    Ci, L; Suhr, J; Pushparaj, V; Zhang, X; Ajayan, P M

    2008-09-01

    Carbon nanotubes are considered short fibers, and polymer composites with nanotube fillers are always analogues of random, short fiber composites. The real structural carbon fiber composites, on the other hand, always contain carbon fiber reinforcements where fibers run continuously through the composite matrix. With the recent optimization in aligned nanotube growth, samples of nanotubes in macroscopic lengths have become available, and this allows the creation of composites that are similar to the continuous fiber composites with individual nanotubes running continuously through the composite body. This allows the proper utilization of the extreme high modulus and strength predicted for nanotubes in structural composites. Here, we fabricate such continuous nanotube polymer composites with continuous nanotube reinforcements and report that under compressive loadings, the nanotube composites can generate more than an order of magnitude improvement in the longitudinal modulus (up to 3,300%) as well as damping capability (up to 2,100%). It is also observed that composites with a random distribution of nanotubes of same length and similar filler fraction provide three times less effective reinforcement in composites.

  11. Biomimetic Approach to Solar Cells Based on TiO2 Nanotubes

    National Research Council Canada - National Science Library

    Allen, Jan L; Lee, Ivan C; Wolfenstine, Jeff

    2008-01-01

    The goal of this research was to explore the use of nanotube titanium dioxide (TiO2) as an electrode material in dye-sensitized solar cells in order to further the development of solar cell technology...

  12. Problems of Electromagnetic Filtration of Technological Liquid on the Basis of Iron-Containing Particle Deposition in High-Gradient Magnetic Field

    Directory of Open Access Journals (Sweden)

    R. A. Muradova

    2006-01-01

    Full Text Available Conventional methods for separation of liquid systems are out of use for cleaning liquid products of chemical technology from finely dispersed micro-quantity of iron-containing particles. Majority of these impurities is characterized by magneto-receptive behavior, in other words they exhibit a capability for magnetic precipitation; so application of magnetic precipitating filters shows promise for a removal of such particles.

  13. Technological Innovations in Magnetic Resonance for Early Detection of Cardiovascular Diseases.

    Science.gov (United States)

    Santarelli, Maria F; Positano, Vincenzo; Martini, Nicola; Valvano, Giuseppe; Landini, Luigi

    2016-01-01

    Most recent technical innovations in cardiovascular MR imaging (CMRI) are presented in this review. They include hardware and software developments, and novelties in parametric mapping. All these recent improvements lead to high spatial and temporal resolution and quantitative information on the heart structure and function. They make it achievable ambitious goals in the field of magnetic resonance, such as the early detection of cardiovascular pathologies. In this review article, we present recent innovations in CMRI, emphasizing the progresses performed and the solutions proposed to some yet opened technical problems.

  14. A new spin-functional MOSFET based on magnetic tunnel junction technology: pseudo-spin-MOSFET

    OpenAIRE

    Shuto, Yusuke; Nakane, Ryosho; Wang, Wenhong; Sukegawa, Hiroaki; Yamamoto, Shuu'ichirou; Tanaka, Masaaki; Inomata, Koichiro; Sugahara, Satoshi

    2009-01-01

    We fabricated and characterized a new spin-functional MOSFET referred to as a pseudo-spin-MOSFET (PS-MOSFET). The PS-MOSFET is a circuit using an ordinary MOSFET and magnetic tunnel junction (MTJ) for reproducing functions of spin-transistors. Device integration techniques for a bottom gate MOSFET using a silicon-on-insulator (SOI) substrate and for an MTJ with a full-Heusler alloy electrode and MgO tunnel barrier were developed. The fabricated PS-MOSFET exhibited high and low transconductanc...

  15. The status of the federal magnetic fusion program, or fusion in transition: from science to technology

    International Nuclear Information System (INIS)

    Kane, J.S.

    1983-01-01

    The current status of magnetic fusion is summarized. The science is in place; the application must be made. Government will have to underwrite the risk of the program, but the private sector must manage it. Government officials must be convinced fusion is in the interest of the taxpayer, private sector decision makers that it is commercial. Questions concerning reliability, availability, first cost, safety, environment, and sociology must be asked. Fusion energy is essentially inexhaustible, appears environmentally acceptable, and is one of a very short list of alternatives

  16. Large-scale synthesis of coiled-like shaped carbon nanotubes using bi-metal catalyst

    Science.gov (United States)

    Krishna, Vemula Mohana; Somanathan, T.; Manikandan, E.; Umar, Ahmad; Maaza, M.

    2018-02-01

    Carbon nanomaterials (CNMs), especially carbon nanotubes (CNTs) with coiled structure exhibit scientifically fascinating. They may be projected as an innovative preference to future technological materials. Coiled carbon nanotubes (c-CNTs) on a large-scale were successfully synthesized with the help of bi-metal substituted α-alumina nanoparticles catalyst via chemical vapor deposition (CVD) technique. Highly spring-like carbon nanostructures were observed by field emission scanning electron microscope (FESEM) examination. Furthermore, the obtained material has high purity, which correlates the X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. Raman spectroscopy reveals that the carbon multi layers are well graphitized and crystalline, even if they have defects in its structure due to coiled morphology. High-resolution transmission electron microscope (HRTEM) describes internal structure and dia of the product. Ultimately, results support the activity of bi-metal impregnated α-alumina nanoparticles catalyst to determine the high yield, graphitization and internal structure of the material. We have also studied the purified c-CNTs magnetic properties at room temperature and will be an added advantage in several applications.

  17. Endovascular brain intervention and mapping in a dog experimental model using magnetically-guided micro-catheter technology.

    Science.gov (United States)

    Kara, Tomas; Leinveber, Pavel; Vlasin, Michal; Jurak, Pavel; Novak, Miroslav; Novak, Zdenek; Chrastina, Jan; Czechowicz, Krzysztof; Belehrad, Milos; Asirvatham, Samuel J

    2014-06-01

    Despite the substantial progress that has been achieved in interventional cardiology and cardiac electrophysiology, endovascular intervention for the diagnosis and treatment of central nervous system (CNS) disorders such as stroke, epilepsy and CNS malignancy is still limited, particularly due to highly tortuous nature of the cerebral arterial and venous system. Existing interventional devices and techniques enable only limited and complicated access especially into intra-cerebral vessels. The aim of this study was to develop a micro-catheter magnetically-guided technology specifically designed for endovascular intervention and mapping in deep CNS vascular structures. Mapping of electrical brain activity was performed via the venous system on an animal dog model with the support of the NIOBE II system. A novel micro-catheter specially designed for endovascular interventions in the CNS, with the support of the NIOBE II technology, was able to reach safely deep intra-cerebral venous structures and map the electrical activity there. Such structures are not currently accessible using standard catheters. This is the first study demonstrating successful use of a new micro-catheter in combination with NIOBE II technology for endovascular intervention in the brain.

  18. Development of tritium technology for the United States magnetic fusion energy program

    International Nuclear Information System (INIS)

    Anderson, J.L.; Wilkes, W.R.

    1980-01-01

    Tritium technology development for the DOE fusion program is taking place principally at three laboratories, Mound Facility, Argonne National Laboratory and the Los Alamos Scientific Laboratory. This paper will review the major aspects of each of the three programs and look at aspects of the tritium technology being developed at other laboratories within the United States. Facilities and experiments to be discussed include the Tritium Effluent Control Laboratory and the Tritium Storage and Delivery System for the Tokamak Fusion Test Reactor at Mound Facility; the Lithium Processing Test Loop and the solid breeder blanket studies at Argonne; and the Tritium Systems Test Assembly at Los Alamos

  19. Fusion an introduction to the physics and technology of magnetic confinement fusion

    CERN Document Server

    Stacey, Weston M

    2010-01-01

    This second edition of a popular textbook is thoroughly revised with around 25% new and updated content.It provides an introduction to both plasma physics and fusion technology at a level that can be understood by advanced undergraduates and graduate students in the physical sciences and related engineering disciplines.As such, the contents cover various plasma confinement concepts, the support technologies needed to confine the plasma, and the designs of ITER as well as future fusion reactors.With end of chapter problems for use in courses.

  20. Conceptual design of an active magnetic regenerative heat circulator based on self-heat recuperation technology

    International Nuclear Information System (INIS)

    Kotani, Yui; Kansha, Yasuki; Tsutsumi, Atsushi

    2013-01-01

    A conceptual design of an active magnetic regenerative (AMR) heat circulator for self-heat recuperation to realize energy savings in thermal processes is proposed. The process fluid heat is recuperated by the magnetocaloric effect of ferromagnetic material through the AMR heat circulation cycle. In an AMR heat circulator, all the process fluid heat is circulated and no make-up heat is added to raise the process fluid to its set temperature. A one-dimensional mathematical model of the AMR heat circulator was constructed to understand its behavior and verify its energy-saving potential. From the constructed one-dimensional mathematical model, it is seen that AMR heat circulator has potential to drastically reduce the total energy consumption in a thermal process. The temperature–entropy diagram shows that in order to gain the maximum energy saving, optimization of the parameters such as the flow rate and geometry of the ferromagnetic working material beds is needed. - Highlights: • Self-heat recuperative active magnetic regenerative heat circulator is introduced. • One-dimensional model is constructed to verify its energy-saving potential. • Total energy consumption in thermal process is drastically reduced. • Further energy can be saved by reducing the overlapping of thermodynamic cycles

  1. Spanish Minister of Science and Technology visits the LHC magnet test facility

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    H.E. Mr Josep Piqué i Camps, Minister of Science and Technology, Spain, visited CERN in November. Here Felix Rodriguez Mateos (right) explains aspects of the test facility to the Minister (left). Between them are M. Aguilar Benitez, Spanish delegate to CERN Council (left), and Francisco Giménez-Reyna, Spanish delegate to the CERN Finance Committee.

  2. Focus on Materials Analysis and Processing in Magnetic Fields

    Directory of Open Access Journals (Sweden)

    Yoshio Sakka, Noriyuki Hirota, Shigeru Horii and Tsutomu Ando

    2009-01-01

    Full Text Available Recently, interest in the applications of feeble (diamagnetic and paramagnetic magnetic materials has grown, whereas the popularity of ferromagnetic materials remains steady and high. This trend is due to the progress of superconducting magnet technology, particularly liquid-helium-free superconducting magnets that can generate magnetic fields of 10 T and higher. As the magnetic energy is proportional to the square of the applied magnetic field, the magnetic energy of such 10 T magnets is in excess of 10 000 times that of conventional 0.1 T permanent magnets. Consequently, many interesting phenomena have been observed over the last decade, such as the Moses effect, magnetic levitation and the alignment of feeble magnetic materials. Researchers in this area are widely spread around the world, but their number in Japan is relatively high, which might explain the success of magnetic field science and technology in Japan.Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. The 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3, which was held on 14–16 May 2008 at the University of Tokyo, Japan, focused on various topics including magnetic field effects on chemical, physical, biological, electrochemical, thermodynamic and hydrodynamic phenomena; magnetic field effects on the crystal growth and processing of materials; diamagnetic levitation, the magneto-Archimedes effect, spin chemistry, magnetic orientation, control of structure by magnetic fields, magnetic separation and purification, magnetic-field-induced phase transitions, properties of materials in high magnetic fields, the development of NMR and MRI, medical applications of magnetic fields, novel magnetic phenomena, physical property measurement by magnetic fields, and the generation of high magnetic fields.This focus issue compiles 13 key papers selected from the proceedings

  3. FOREWORD: Focus on Materials Analysis and Processing in Magnetic Fields Focus on Materials Analysis and Processing in Magnetic Fields

    Science.gov (United States)

    Sakka, Yoshio; Hirota, Noriyuki; Horii, Shigeru; Ando, Tsutomu

    2009-03-01

    Recently, interest in the applications of feeble (diamagnetic and paramagnetic) magnetic materials has grown, whereas the popularity of ferromagnetic materials remains steady and high. This trend is due to the progress of superconducting magnet technology, particularly liquid-helium-free superconducting magnets that can generate magnetic fields of 10 T and higher. As the magnetic energy is proportional to the square of the applied magnetic field, the magnetic energy of such 10 T magnets is in excess of 10 000 times that of conventional 0.1 T permanent magnets. Consequently, many interesting phenomena have been observed over the last decade, such as the Moses effect, magnetic levitation and the alignment of feeble magnetic materials. Researchers in this area are widely spread around the world, but their number in Japan is relatively high, which might explain the success of magnetic field science and technology in Japan. Processing in magnetic fields is a rapidly expanding research area with a wide range of promising applications in materials science. The 3rd International Workshop on Materials Analysis and Processing in Magnetic Fields (MAP3), which was held on 14-16 May 2008 at the University of Tokyo, Japan, focused on various topics including magnetic field effects on chemical, physical, biological, electrochemical, thermodynamic and hydrodynamic phenomena; magnetic field effects on the crystal growth and processing of materials; diamagnetic levitation, the magneto-Archimedes effect, spin chemistry, magnetic orientation, control of structure by magnetic fields, magnetic separation and purification, magnetic-field-induced phase transitions, properties of materials in high magnetic fields, the development of NMR and MRI, medical applications of magnetic fields, novel magnetic phenomena, physical property measurement by magnetic fields, and the generation of high magnetic fields. This focus issue compiles 13 key papers selected from the proceedings of MAP3. Other

  4. Continuum theory for nanotube piezoelectricity.

    Science.gov (United States)

    Michalski, P J; Sai, Na; Mele, E J

    2005-09-09

    We develop and solve a continuum theory for the piezoelectric response of one-dimensional nanotubes and nanowires, and apply the theory to study electromechanical effects in boron-nitride nanotubes. We find that the polarization of a nanotube depends on its aspect ratio, and a dimensionless constant specifying the ratio of the strengths of the elastic and electrostatic interactions. The solutions of the model as these two parameters are varied are discussed. The theory is applied to estimate the electric potential induced along the length of a boron-nitride nanotube in response to a uniaxial stress.

  5. Mechanical properties of carbon nanotubes

    Science.gov (United States)

    Salvetat, J.-P.; Bonard, J.-M.; Thomson, N. H.; Kulik, A. J.; Forró, L.; Benoit, W.; Zuppiroli, L.

    A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing. These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a qualitative relationship between the Young's modulus of a nanotube and the amount of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before suitable engineering materials can be produced.

  6. Fabricating Copper Nanotubes by Electrodeposition

    Science.gov (United States)

    Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

    2009-01-01

    Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

  7. A Report on the Development of Rare Earth-Cobalt Permanent Magnet Technology - Japan.

    Science.gov (United States)

    1981-07-01

    Implantable pumps and valves , head support harness in development). C. MICROWAVE AND ION BEAM TECHNOLOGY 1. Microwave Tubes: TWT PPM focusing, klystrons...III and IV were devoted to various medical applications that employ REPM. These included various dental prosthetic devices, tech- niques for measuring...minimize losses due to fracture in handling or heat treatment. Very little work has been done on this topic in the West or in Japan. The only two papers

  8. Gravity, Magnetic and Electromagnetic Gradiometry; Strategic technologies in the 21st century

    Science.gov (United States)

    Veryaskin, Alexey V.

    2018-02-01

    Gradiometry is a multidisciplinary area that combines theoretical and applied physics, ultra-low noise electronics, precision engineering, and advanced signal processing. Applications include the search for oil, gas, and mineral resources, GPS-free navigation, defence, space missions, and medical research. This book provides readers with a comprehensive introduction, history, potential applications, and current developments in relation to some of the most advanced technologies in the 21st Century.

  9. Magnetic-Field-Assisted Assembly of Ordered Multifunctional Ceramic Nanocomposites for Extreme Environments

    Science.gov (United States)

    2016-04-01

    SUBJECT TERMS carbon nanotubes, composite, electromagnetic shielding , extreme environments, magnetism, fibers, woven composite, boron nitride...The samples were sealed in glass vial and exposed to the magnetic field immediately after deposition prior to crystallization of PEG that allowed

  10. The role of defects in the design of space elevator cable: From nanotube to megatube

    Energy Technology Data Exchange (ETDEWEB)

    Pugno, Nicola M. [Department of Structural Engineering and Geotechnics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy)], E-mail: nicola.pugno@polito.it

    2007-09-15

    Researchers are claiming that the feasibility of space elevator cable is now realistic, thanks to carbon nanotube technology, proposing its realization within a decade. However, the current view of basing the design of the megacable on the theoretical strength of a single carbon nanotube is naive, as has recently been emphasized. In this paper the role of thermodynamically unavoidable atomistic defects with different size and shape is quantified on brittle fracture, fatigue and elasticity, for nanotubes and nanotube bundles. Nonasymptotic regimes, elastic plasticity, rough cracks, finite domains and size effects are also discussed. The results are compared with atomistic simulations and nanotensile tests of carbon nanotubes. Key simple formulas for the design of a flaw-tolerant space elevator megacable are reported, suggesting that it would need a taper ratio (for uniform stress) of about two orders of magnitude larger than currently proposed.

  11. Strategies for dispersing carbon nanotubes in highly viscous polymers

    NARCIS (Netherlands)

    Grossiord, N.; Loos, J.; Koning, C.E.

    2005-01-01

    We describe a new technique based on latex technology, which allows the production of conductive composites with potential applications in electronics. These composites consist of exfoliated single-wall nanotubes in a polymer matrix of choice, with very low percolation threshold.

  12. Angular and geometry dependence of coercivity and remanence nickel nanotube isolated

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, J.L.; Davila, Y.G.; Garcia, R.P.; Del Toro, A.D.; Martins, I.G.; Hernandez, E.P. [Universidade Federal de Pernambuco (UFPE), PE (Brazil)

    2016-07-01

    Fell text: During the last decade, interesting properties of magnetic nanotubes have attracted great attention. Besides their basic properties, there is evidence that they can be used in the production of magnetic devices. More recently, magnetic nanotubes have been grown motivating intense research in the field. Magnetic measurements, numerical simulations and analytical calculations on such tubes have identied two main states: an in-plane magnetic ordering, namely, the uxclosure vortex state, and a uniform state with all the magnetic moments pointing parallel to the axis of the tube. Nanotubes exhibit a core-free magnetic conguration leading to uniform switching elds, guaranteeing reproducibility and due to their low density they can oat in solutions making them suitable for applications in biotechnology. For the analysis of the magnetic properties of nanotubes through computer simulation, the internal energy has the following contributions: Exchange of interaction, magnetocrystalline anisotropy, demagnetizing energy, anisotropy of form and Zeeman energy. Geometrically, tubes are characterized by their external and internal radii, R and a, respectively, and length H. It is convenient to dene the ratio, beta = a / R, so that beta = 0 represents a solid cylinder and beta - -> 1 corresponds to a very narrow tube. It was made a study of the anisotropic magnetization, varying the angle of application of the magnetic field, an angle 0° ≤ theta ≤ 90° with the axis z. In our work, we used the internal radius equal to 20 nm and the outer radius of 40 nm, that is the ratio beta = 0.5, the length of the nanotube is 10⌃-3 m. The magneticmicro-simulation is performed using the typical parameters Ni: saturation magnetization, MS = 4,85.10⌃5 A/m, your exchange constant, A = 9,0.10⌃12 J / m. Arrays nanotubes nickel are investigated through micromagnetic simulation by Object Oriented Micromagnetic Framework (OOMMF). We analyze the results for the hysteresis loop

  13. Transport Phenomena in Nanowires, Nanotubes, and Other Low-Dimensional Systems

    KAUST Repository

    Montes, Enrique

    2017-01-01

    Nanoscale materials are not new in either nature or physics. However, the recent technological improvements have given scientists new tools to understand and quantify phenomena that occur naturally due to quantum confinement effects. In general, these phenomena induce remarkable optical, magnetic, and electronic properties in nanoscale materials in contrast to their bulk counterpart. In addition, scientists have recently developed the necessary tools to control and exploit these properties in electronic devices, in particular field effect transistors, magnetic memories, and gas sensors. In the present thesis we implement theoretical and computational tools for analyzing the ground state and electronic transport properties of nanoscale materials and their performance in electronic devices. The ground state properties are studied within density functional theory using the SIESTA code, whereas the transport properties are investigated using the non-equilibrium Green\\'s functions formalism implemented in the SMEAGOL code. First we study Si-based systems, as Si nanowires are believed to be important building blocks of the next generation of electronic devices. We derive the electron transport properties of Si nanowires connected to Au electrodes and their dependence on the nanowire growth direction, diameter, and length. At equilibrium Au-nanowire distance we find strong electronic coupling between electrodes and nanowire, resulting in low contact resistance. For the tunneling regime, the decay of the conductance with the nanowire length is rationalized using the complex band structure. The nanowires grown along the (110) direction show the smallest decay and the largest conductance and current. Due to the high spin coherence in Si, Si nanowires represent an interesting platform for spin devices. Therefore, we built a magnetic tunneling junction by connecting a (110) Si nanowire to ferromagnetic Fe electrodes. We have find a substantial low bias magnetoresistance of

  14. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes.

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  15. High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes

    Science.gov (United States)

    Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

    2017-09-01

    As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

  16. Nuclear Technology. Course 32: Nondestructive Examination (NDE) II. Module 32-3, Fundamentals of Magnetic Particle Testing.

    Science.gov (United States)

    Groseclose, Richard

    This third in a series of six modules for a course titled Nondestructive Examination (NDE) Techniques II explains the principles of magnets and magnetic fields and how they are applied in magnetic particle testing, describes the theory and methods of magnetizing test specimens, describes the test equipment used, discusses the principles and…

  17. Health technology assessment of magnetic resonance imaging of the spine and bone marrow

    International Nuclear Information System (INIS)

    Verstraete, K.L.; Huysse, W.C.J.

    2008-01-01

    The high spatial resolution and the lack of ionizing radiation, makes magnetic resonance imaging the method of choice for imaging most spinal pathology, especially if associated with neurological symptoms. However, due to the high sensitivity of MR imaging, careful correlation between imaging findings and clinical findings is important to ensure appropriate treatment. Substituting radiographic evaluations for rapid MRI in the primary care setting may offer little additional benefit to patients. It may even increase the costs of care but the decisions about the use of imaging depend on judgments concerning whether the small observed improvement in outcome justifies additional cost. Because the presence of an abscess is a major factor in deciding between conservative and surgical treatment, MRI plays an essential role in the decision-making process concerning the treatment of spondylodiscitis. MR is also the method of choice for quantitative evaluation of bone marrow in lymphoma patients when a crucial therapeutic decision has to be made or for the qualitative evaluation of the spinal cord if compression is suspected in primary spinal malignancy or metastatic disease

  18. Magnetic resonance imaging-three-dimensional printing technology fabricates customized scaffolds for brain tissue engineering

    Institute of Scientific and Technical Information of China (English)

    Feng Fu; Chong Chen; Sai Zhang; Ming-liang Zhao; Xiao-hong Li; Zhe Qin; Chao Xu; Xu-yi Chen; Rui-xin Li; Li-na Wang; Ding-wei Peng; Hong-tao Sun; Yue Tu

    2017-01-01

    Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer- aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine.

  19. Health technology assessment of magnetic resonance imaging of the spine and bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Verstraete, K.L. [Department of Radiology, Ghent University, De Pintelaan 185, B-9000 Gent (Belgium)], E-mail: Koenraad.verstraete@ugent.be; Huysse, W.C.J. [Department of Radiology, Ghent University, De Pintelaan 185, B-9000 Gent (Belgium)], E-mail: Wouter.huysse@ugent.be

    2008-02-15

    The high spatial resolution and the lack of ionizing radiation, makes magnetic resonance imaging the method of choice for imaging most spinal pathology, especially if associated with neurological symptoms. However, due to the high sensitivity of MR imaging, careful correlation between imaging findings and clinical findings is important to ensure appropriate treatment. Substituting radiographic evaluations for rapid MRI in the primary care setting may offer little additional benefit to patients. It may even increase the costs of care but the decisions about the use of imaging depend on judgments concerning whether the small observed improvement in outcome justifies additional cost. Because the presence of an abscess is a major factor in deciding between conservative and surgical treatment, MRI plays an essential role in the decision-making process concerning the treatment of spondylodiscitis. MR is also the method of choice for quantitative evaluation of bone marrow in lymphoma patients when a crucial therapeutic decision has to be made or for the qualitative evaluation of the spinal cord if compression is suspected in primary spinal malignancy or metastatic disease.

  20. Isolation of murine postnatal brain microglia for phenotypic characterization using magnetic cell separation technology.

    Science.gov (United States)

    Harms, Ashley S; Tansey, Malú G

    2013-01-01

    To shorten the time between brain harvesting and microglia isolation, and characterization, we utilized the MACS(®) neural dissociation kit followed by OctoMACS(®) CD11b magnetic bead isolation technique to positively select for brain microglia expressing the pan-microglial marker CD11b, a key subunit of the membrane attack complex (MAC). This protocol yields a viable and highly pure (>95%) microglial population of approximately 500,000 cells per pup that is amenable for in vitro characterization within hours or days after being harvested from brain tissue. Primary microglia from C57Bl/6 mice were plated for next-day analyses of morphology and cellular markers by immunocytochemistry or for analysis of gene expression under resting or LPS-stimulated conditions. The ease of isolation enables investigators to perform molecular and cellular analyses without having to wait 1-2 weeks to isolate microglia by conventional methods involving mechanical agitation to dislodge these from astrocyte beds.