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Sample records for acicular ferrite af

  1. Toughening mechanisms of a high-strength acicular ferrite steel heavy plate

    NASA Astrophysics Data System (ADS)

    Cao, Zhi-Qiang; Bao, Yan-Ping; Xia, Zheng-Hai; Luo, Deng; Guo, Ai-Min; Wu, Kai-Ming

    2010-10-01

    An ultra-low carbon acicular ferrite steel heavy plate was obtained with an advanced thermo-mechanical control process-relaxed precipitation controlled transformation (TMCP-RPC) at Xiangtan Steel, Valin Group. The heavy plate has a tensile strength of approximately 600 MPa with a lower yield ratio. The impact toughness of the heavy plate achieves 280 J at -40°C. The fine-grained mixed microstructures of the heavy plate mainly consist of acicular ferrite, granular bainite, and polygonal ferrite. The high strength and excellent toughness of the heavy plate are attributed to the formation of acicular ferrite microstructure. The prevention of blocks of martensite/retained austenite (M/A) and the higher cleanness are also responsible for the superior toughness.

  2. Fracture mechanisms in dual phase steels based on the acicular ferrite + martensite/austenite microstructure

    NASA Astrophysics Data System (ADS)

    Poruks, Peter

    The fracture mechanisms of low carbon microalloyed plate steels based on the acicular ferrite + marten site/austenite microstructure (AF + M/A) are investigated. The final microstructure consists of a dispersed phase of submicron equi-axed martensite particles with a bainitic ferrite matrix. A series of plates with M/A volume fractions of 0.076--0.179 are studied. Brittle fracture is investigated by Instrumented Charpy impact testing of samples at -196°C and subsequent metallography. The M/A particles are identified as the crack nucleation sites and the cleavage fracture stress calculated to be 2400 MPa in a complete AF microstrucuture. This value is significantly larger than in steels that contain significant proportions of conventional bainite. Standard Charpy and Instrumented Charpy impact testing is conducted through a temperature range from -80 to + 22°C to study ductile fracture behaviour. The total absorbed energy is separated into energies of crack nucleation and of crack propagation. It is found that the energy of crack nucleation is weakly dependent on the volume fraction of M/A and completely independent of temperature over the range studied. The crack propagation energy varies significantly with both variables, decreasing with increased volume fraction of M/A and with decreasing temperature. The peak load in the instrumented Charpy data is used to calculate the dynamic fracture toughness, KId, which is found to be 105--120 MPa-m1/2. The void nucleation and void growth stages of ductile fracture are studied by metallographic examination of tensile bars. The sites of void nucleation are identified as inclusions and M/A particles. Voids nucleate at the M/A particles by decohesion of the particle-matrix interface. A constant void nucleation strain of epsilon = 0.90 +/- 0.05 is measured for all of the samples independent of the volume fraction of M/A. A stress-based criterion is used to predict void nucleation and the interface strength is determined to be

  3. Factors Affecting the Inclusion Potency for Acicular Ferrite Nucleation in High-Strength Steel Welds

    NASA Astrophysics Data System (ADS)

    Kang, Yongjoon; Jeong, Seonghoon; Kang, Joo-Hee; Lee, Changhee

    2016-06-01

    Factors affecting the inclusion potency for acicular ferrite nucleation in high-strength weld metals were investigated and the contribution of each factor was qualitatively evaluated. Two kinds of weld metals with different hardenabilities were prepared, in both, MnTi2O4-rich spinel formed as the predominant inclusion phase. To evaluate the factors determining the inclusion potency, the inclusion characteristics of size, phase distribution in the multiphase inclusion, orientation relationship with ferrite, and Mn distribution near the inclusion were analyzed. Three factors affecting the ferrite nucleation potency of inclusions were evaluated: the Baker-Nutting (B-N) orientation relationship between ferrite and the inclusion; the formation of an Mn-depleted zone (MDZ) near the inclusion; and the strain energy around the inclusion. Among these, the first two factors were found to be the most important. In addition, it was concluded that the increased chemical driving force brought about by the formation of an MDZ contributed more to the formation of acicular ferrite in higher-strength weld metals, because the B-N orientation relationship between ferrite and the inclusion was less likely to form as the transformation temperature decreased.

  4. Factors Affecting the Inclusion Potency for Acicular Ferrite Nucleation in High-Strength Steel Welds

    NASA Astrophysics Data System (ADS)

    Kang, Yongjoon; Jeong, Seonghoon; Kang, Joo-Hee; Lee, Changhee

    2016-03-01

    Factors affecting the inclusion potency for acicular ferrite nucleation in high-strength weld metals were investigated and the contribution of each factor was qualitatively evaluated. Two kinds of weld metals with different hardenabilities were prepared, in both, MnTi2O4-rich spinel formed as the predominant inclusion phase. To evaluate the factors determining the inclusion potency, the inclusion characteristics of size, phase distribution in the multiphase inclusion, orientation relationship with ferrite, and Mn distribution near the inclusion were analyzed. Three factors affecting the ferrite nucleation potency of inclusions were evaluated: the Baker-Nutting (B-N) orientation relationship between ferrite and the inclusion; the formation of an Mn-depleted zone (MDZ) near the inclusion; and the strain energy around the inclusion. Among these, the first two factors were found to be the most important. In addition, it was concluded that the increased chemical driving force brought about by the formation of an MDZ contributed more to the formation of acicular ferrite in higher-strength weld metals, because the B-N orientation relationship between ferrite and the inclusion was less likely to form as the transformation temperature decreased.

  5. The role of molybdenum additions and prior deformation on acicular ferrite formation in microalloyed Nb-Ti low-carbon line-pipe steels

    SciTech Connect

    Tang Zhenghua Stumpf, Waldo

    2008-06-15

    Microstructures in Nb-Ti-microalloyed line-pipe steels with various molybdenum additions, consisted mostly of acicular ferrite plus polygonal ferrite after hot rolling and rapid cooling. Structure-sensitive surface relief after etching on shadowed extraction replicas, allowed quantification of the acicular and polygonal ferrite contents. Continuous cooling transformation diagrams of two alloys, one Mo-free and the other containing 0.22% Mo, were determined for cooling rates from 0.1 to 40 deg. C s{sup -1} without and with prior deformation of the austenite below the nil-recrystallisation temperature. Molybdenum additions slightly enhanced the acicular ferrite formation in the strain-free austenite whereas prior deformation had a much greater effect, and strongly promoted acicular ferrite formation in both alloys. Thin foil electron microscopy of acicular ferrite in these low-inclusion content alloys showed a preference for parallel acicular ferrite laths with less 'chaotically' nucleated laths.

  6. Effect of Ti-containing inclusions on the nucleation of acicular ferrite and mechanical properties of multipass weld metals.

    PubMed

    Fattahi, M; Nabhani, N; Hosseini, M; Arabian, N; Rahimi, E

    2013-02-01

    In the present study, the influence of Ti-containing inclusions on the development of acicular ferrite microstructure and mechanical properties in the multipass weld metals has been studied. Shielded metal arc weld deposits were prepared by varying titanium content in the range of 0.003-0.021%. The variation in the titanium content was obtained by the addition of different amounts of titanium oxide nanoparticles to the electrode coating. The dispersion of titanium oxide nanoparticles, composition of inclusions, microstructural analysis, tensile properties and Charpy impact toughness were evaluated. As the amount of Ti-containing inclusions in the weld metal was increased, the microstructure of the weld metal was changed from the grain boundary allotriomorphic ferrite structure to acicular ferrite with the intragranular nucleation of ferrite on the Ti-containing inclusions, and the mechanical properties were improved. This improvement is attributable to the increased percentage of acicular ferrite due to the uniform dispersion of Ti-containing inclusions and the pinning force of oxide nanoparticles against the growth of allotriomorphic ferrite and Widmanstätten ferrite from the austenite grain boundaries. PMID:23238108

  7. Upper acicular ferrite formation in a medium-carbon microalloyed steel by isothermal transformation: Nucleation enhancement by CuS

    NASA Astrophysics Data System (ADS)

    Madariaga, I.; Romero, J. L.; Gutiérrez, I.

    1998-03-01

    The isothermal transformation vs time of a medium-carbon microalloyed steel at 450°C, following austenitization at 1250°C for 45 minutes, has been investigated using optical microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). At short times, the fine microstructure of acicular ferrite is nucleated at MnS inclusions, which are covered by a shell of a hexagonal CuS phase. The special orientation between MnS and the CuS crystals of this shell enables the formation of a low-energy interface between the ferrite and the inclusion with, at the same time, the ferrite satisfying one of the 24 variants of the orientation relationship into the Bain region with austenite. As the treatment times are increased, the increase in the volume fraction of acicular ferrite being formed raises the carbon concentration of the austenite, such that some retained austenite instead of martensite is observed for these intermediate treatment times. This retained austenite transforms to ferrite plus carbides at long treatment times, resulting in a final microstructure of acicular ferrite, very similar in nature to those encountered in the case of upper bainite formation.

  8. Obtaining an Acicular Microstructure by Thermomechanical Sequences in X-80 Steel

    NASA Astrophysics Data System (ADS)

    de Castro, Renato Soares; Pedrosa, Igor Rafael Vilarouco; Yadava, Yogendra Prasad; Ferreira, Ricardo Artur Sanguinetti

    2014-09-01

    Microstructural modification is one of the routes to increase strength and toughness in high-strength low-alloy (HSLA) steels. Considering the good mechanical properties of acicular ferrite, thermomechanical sequences, with continuous cooling or isothermal treatment, were applied in an X-80 HSLA steel to obtain dominant acicular microstructure. Electron microscopy and electron back-scattered diffraction (EBDS) analyses were performed to identify and quantify microstructural changes. It was possible to correlate the misorientation boundaries profile with the occurrence of acicular microstructure, which was characterized by a high quantity of substructured and deformed units. Thermomechanical sequences with continuous cooling were more effective for obtaining acicular microstructure than sequences of isothermal treatments.

  9. Thermal Analysis of Acicular Shaped Magnetite

    NASA Technical Reports Server (NTRS)

    Lauer, H. V., Jr.; Ming, D. W.; Golden, D. C.

    2003-01-01

    We are in the process of developing a database on the thermal properties of well-characterized Martian analog materials in support of future Mars surface missions. The database contains the thermal behaviors of these analog materials under reduced and Earth ambient pressures. Magnetite in planetary materials has received considerable attention in recent years since the identification of fine grain single-domain magnetite in Martian meteorite ALH84001 and their possible link to past life on Mars (i.e., possible biominerals of magnetotactic bacteria). Because of its possible importance to Mars science, we report here the thermal properties of magnetite particles with acicular morphology, i.e., needle-shaped magnetite. Acicular shaped magnetite can be commercially produced from goethite (FeOOH) as the starting material via a H2 reduction process. However, instead of using this process or procedure, we report here on the thermal characterization of acicular magnetite formed under reducing conditions from well-characterized needle-shaped goethite at low temperature in controlled CO-CO2 1-bar atmosphere gas mixing furnaces.

  10. Kinetics and formation mechanisms of intragranular ferrite in V-N microalloyed 600 MPa high strength rebar steel

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Wang, Fu-ming; Li, Chang-rong

    2016-04-01

    To systematically investigate the kinetics and formation mechanisms of intragranular ferrite (IGF), isothermal heat treatment in the temperature range of 450°C to 600°C with holding for 30 s to 300 s, analysis of the corresponding microstructures, and observation of the precipitated particles were conducted in V-N microalloyed 600 MPa high strength rebar steel. The potency of V(C,N) for IGF nucleation was also analyzed statistically. The results show that the dominant microstructure transforms from bainite (B) and acicular ferrite (AF) to grain boundary ferrite (GBF), intragranular polygonal ferrite (IPF), and pearlite (P) as the isothermal temperature increases from 450°C to 600°C. When the holding time at 600°C is extended from 30 s to 60 s, 120 s, and 300 s, the GBF content ranges from 6.0vol% to 6.5vol% and the IPF content increases from 0.5vol% to 2.8vol%, 13.1vol%, and 13.5vol%, respectively, because the ferrite transformation preferentially occurs at the grain boundaries and then occurs at the austenite grains. Notably, V(C,N) particles are the most effective nucleation site for the formation of IPF, accounting for 51% of the said formation.

  11. Ferrite morphology and variations in ferrite content in austenitic stainless steel welds

    SciTech Connect

    David, S.A.; Hanzelka, S.E.; Haltom, C.P.

    1981-07-01

    Four distinct ferrite morphologies have been identified in type 308 stainless steel multipass welds: vermicular, lacy, acicular, and globular. The first three ferrite types are related to transformations following solidification and the fourth is related to the shape instability of the residual ferrite. An earlier study showed that most of the ferrite observed in austenitic stainless steel welds contaning a duplex structure may be identified as residual primary ferrite resulting from incomplete delta ..-->.. ..gamma.. transformation during solidification and/or residual ferrite after Widmanstaetten austenite precipitation in primary ferrite. These modes of ferrite formation can be used to explain observed ferrite morphologies in austenitic stainless steel welds. Variations in ferrite content within the weld were related to weld metal composition, ferrite morphology, and dissolution of ferrite resulting from thermal cycles during subsequent weld passes. An investigation of the type 308 stainless steel filler metal solidified over cooling rates ranging from 7 to 1600/sup 0/C/s showed that the cooling rate of the weld metal within the freezing range of the alloy affects the amount of ferrite in the microstructure very litte. However, the scale of the solidification substructure associated with various solidification rates may influence the ferrite dissolution kinetics.

  12. Ferrite morphology and variations in ferrite content in austenitic stainless steel welds

    SciTech Connect

    David, S.A.

    1981-04-01

    Four distinct ferrite morphologies have been identified in Type 308 stainless steel multipass welds: vermicular, lacy, acicular, and globular. The first three ferrite types are related to transformations following solidfication and the fourth is related to the shape instability of the residual ferrite. An earlier study showed that most of the ferrite observed in austenitic stainless steel welds containing a duplex structure may be identified as residual primary ferrite resulting from incomplete delta ..-->.. ..gamma.. transformation during solidification and/or residual ferrite after Widmanstatten austenite precipitation in primary ferrite. These modes of ferrite formation can be used to explain observed ferrite morphologies in austenitic stainless steel welds. Variations in ferrite content within the weld were also related to weld metal composition, ferrite morphology, and dissolution of ferrite resulting from thermal cycles during subsequent weld passes. An investigation of the Type 308 stainless steel filler metal solidified over cooling rates ranging from 7 to 1600/sup 0/C/s (44.6 to 2912/sup 0/F/s) showed that the cooling rate of the weld metal within the freezing range of the alloy affects the amount of ferrite in the microstructure very little. However, the scale of the solidification substructure associated with various solidification rates may influence the ferrite dissolution kinetics.

  13. Ferrite-Martensite Band Formation During the Intercritical Annealing

    NASA Astrophysics Data System (ADS)

    Etesami, S. A.; Enayati, M. H.

    2016-02-01

    Microstructural evolution during the intercritical annealing at 740 and 770 °C for 120-900 s in a low-carbon low-alloy steel from the initial martensitic matrix was studied by electron microscopy equipped with energy dispersive x-ray spectroscopy and x-ray diffraction. It was seen that during the intercritical annealing, the martensitic structure changes to the tempered martensite with carbides. The results depicted that the temperature and time of intercritical annealing influence significantly the distribution and amount of the formed carbides. Two types of austenite morphology were identified to grow simultaneously, i.e., globular and acicular. A longer annealing time led to the coarse globular and thick acicular austenite morphology. The austenite with globular morphology nucleated preferably at prior austenite grain boundary triple and quadruple junctions. The austenite with globular and acicular morphology was developed in Mn-rich and -poor regions, respectively. The globular austenite morphology intensified the banded microstructure of ferrite-martensite dual-phase steel, whereas the acicular austenite morphology led to a more isotropic microstructure. The experimental results illustrated that the intercritical temperature is a significant factor which can contribute to intensify the banded ferrite-martensite microstructure. The volume fractions of austenite with globular and acicular morphology were quantitatively measured. The volume fraction of globular to acicular morphology of austenite was high and low at 770 and 740 °C, respectively.

  14. Infrared reflectance spectra and formalism of precipitation of acicular magnetic particles in network glasses

    NASA Astrophysics Data System (ADS)

    Ram, S.; Ram, K.

    1996-06-01

    1-2 mm thin platelets of borate or silicate glasses precipitate peculiarly isolated magnetic particles (of micrometer sizes) of hexagonal ferrites, spinel ferrites, or garnets at reaction temperature. A small 0.5-3.0 mol % additive of Ag 2O, Bi 2O 3 or P 2O 5 in these glasses behaves as a strong catalyst in undercooling the melt (in the shape of the platelets) in a truly amorphous metastable glass state of locally ordered network of interconnected basis structural units. In a typical 35BaO-25Fe 2O 3-40B 2O 3 borate glass, for example, the ordered structure in the 1-2 mm thin platelets results in 15-52 cm -1 increase in the BO stretching vibration frequencies over the usual values in the bulk. The surface tension σ (which is modified by the additives) of the glass-liquid facilitates the chemical ordering of planar configurations of interconnected (B 3O 4.5) n → 8 boroxol rings one over other along the surface of the platelets. On isothermal annealing at 500-850°C, the planar network configurations (α) nucleate planar α-β interfaces with solid aggregates (β) of the immiscible (at this temperature) Ba 2+ and Fe 3+ cations caused in the network in the thermal induced recrystallization process of BaFe 12O 19 hexagonal ferrite. The initial shape and size of the α-β interface depends (in addition to the σ and the free-energy difference ΔGv between the two phases α and β) on the size and shape of the crystal (β) unit cell and the local structure of the glass. It therefore assumes an elongated shape in the elongated P6 3/mmc hexagonal crystal lattice (of crystallographic axial ration c/ a ˜ 3.94) of BaFe 12O 19 ferrite. That ultimately grows and precipitates in BaFe 12O 19 single crystal in the presumed acicular shape (along the c-axis) over the network, following the flow of the heat released in the reaction along the planar interface, maintained by the strong surface tension σ, surface anisotropy (δ), and α-β wetting. The results are modelled and

  15. Porous acicular mullite obtained by controlled oxidation of waste molybdenum disilicide

    SciTech Connect

    Bučevac, Dušan; Dapčević, Aleksandra; Maksimović, Vesna

    2014-02-01

    Highlights: • Waste MoSi{sub 2} heating elements were used as starting material for fabrication of porous acicular mullite. • Calcined MoSi{sub 2} powder was source of SiO{sub 2} and pore former at the same time. • Porous acicular mullite is promising material for filtration of diesel engine exhaust. • Samples with decent mechanical integrity and porosity of more than 60% were fabricated. - Abstract: Porous acicular mullite was fabricated by using waste MoSi{sub 2} heating element and Al{sub 2}O{sub 3}. Careful calcination of the pulverized heating element led to the formation of a mixture of MoO{sub 3} and amorphous SiO{sub 2}. This mixture was employed as both SiO{sub 2} precursor and pore former. The oxidation of MoSi{sub 2} and mullite formation were studied. The effect of fabrication temperature on phase composition, porosity, grain morphology, and compressive strength of sintered mullite was examined. Pure mullite with porosity of more than 60% and compressive strength of ∼20 MPa was obtained at temperature as low as 1300 °C. The microstructure consisted of elongated, rectangular, prism-like grains which are known to be effective in filtration of diesel engine exhaust. The increase in sintering temperature caused the change of grain morphology and reduction in compressive strength.

  16. Microstructure and properties of pipeline steel with a ferrite/martensite dual-phase microstructure

    SciTech Connect

    Li Rutao Zuo Xiurong Hu Yueyue Wang Zhenwei Hu, Dingxu

    2011-08-15

    In order to satisfy the transportation of the crude oil and gas in severe environmental conditions, a ferrite/martensite dual-phase pipeline steel has been developed. After a forming process and double submerged arc welding, the microstructure of the base metal, heat affected zone and weld metal was characterized using scanning electron microscopy and transmission electron microscopy. The pipe showed good deformability and an excellent combination of high strength and toughness, which is suitable for a pipeline subjected to the progressive and abrupt ground movement. The base metal having a ferrite/martensite dual-phase microstructure exhibited excellent mechanical properties in terms of uniform elongation of 7.5%, yield ratio of 0.78, strain hardening exponent of 0.145, an impact energy of 286 J at - 10 deg. C and a shear area of 98% at 0 deg. C in the drop weight tear test. The tensile strength and impact energy of the weld metal didn't significantly reduce, because of the intragranularly nucleated acicular ferrites microstructure, leading to high strength and toughness in weld metal. The heat affected zone contained complete quenching zone and incomplete quenching zone, which exhibited excellent low temperature toughness of 239 J at - 10 deg. C. - Research Highlights: {yields}The pipe with ferrite/martensite microstructure shows high deformability. {yields}The base metal of the pipe consists of ferrite and martensite. {yields}Heat affected zone shows excellent low temperature toughness. {yields}Weld metal mainly consists of intragranularly nucleated acicular ferrites. {yields}Weld metal shows excellent low temperature toughness and high strength.

  17. Precipitation of sigma and chi phases in δ-ferrite of Type 316FR weld metals

    SciTech Connect

    Chun, Eun Joon; Baba, Hayato; Nishimoto, Kazutoshi; Saida, Kazuyoshi

    2013-12-15

    The decomposition behavior and kinetics of δ-ferrite are examined using aging treatments between 873 and 1073 K for Type 316FR stainless steel weld metals with different solidification modes (316FR AF, 316FR FA). The dominant precipitates are sigma, chi, and secondary austenite nucleated at δ-ferrite/austenite interfaces or in the interior of the ferrite grains. These precipitates consume all the ferrite during isothermal aging in both 316FR AF and FA weld metals. Differences in the precipitation behavior (precipitation initiation time and precipitation speed) between weld metals can be explained by i) the degree of Cr and Mo microsegregation within δ-ferrite or austenite near ferrite and ii) the nucleation sites induced due to the solidification mode (AF or FA), such as the ferrite amount. For both weld materials, a Johnson–Mehl-type equation can express the precipitation behavior of the sigma + chi phases and quantitatively predict the behavior at the service-exposure temperatures of a fast breed reactor. - Highlights: • Precipitation of σ and χ phase in Type 316FR welds (two solidification modes) • Different precipitation behaviors: precipitation initiation time and growth speed • Johnson-Mehl–type equation is the most applicable to the precipitation behaviors • Precipitation behaviors are predicted under service conditions of FBRs.

  18. Cobalt oxide acicular nanorods with high sensitivity for the non-enzymatic detection of glucose.

    PubMed

    Kung, Chung-Wei; Lin, Chia-Yu; Lai, Yi-Hsuan; Vittal, R; Ho, Kuo-Chuan

    2011-09-15

    Acicular cobalt oxide nanorods (CoONRs) were prepared for the non-enzymatic detection of glucose, first by directly growing layered cobalt carbonate hydroxide (LCCH) on a conducting fluorine-doped tin oxide (FTO) substrate using a simple chemical bath deposition (CBD) technique and then by transforming the LCCH into CoONRs through pyrolysis. The composition and grain size of the films of LCCH and CoONRs were verified by X-ray diffraction (XRD); their morphologies were examined by scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images. CoONRs showed high electrocatalytic activity for the electro-oxidation of glucose in alkaline media, and the activity was strongly influenced by NaOH concentration, annealing temperature of CoONRs, and thickness of CoONRs film. The pertinent sensor could be successfully used for the quantification of glucose by amperometric method. The sensing parameters include wide linear range up to 3.5 mM, a high sensitivity of 571.8 μA/(cm(2) mM), and a remarkable low detection limit of 0.058 μM. The CoONRs modified electrode exhibited a high selectivity for glucose in human serum, against ascorbic acid, uric acid, and acetaminophen. PMID:21767942

  19. Growth characteristics of ultra long double-ended acicular ZnO synthesized by a hydrothermal process

    NASA Astrophysics Data System (ADS)

    Tzeng, S. K.; Hon, M. H.; Leu, I. C.

    2009-10-01

    Double-ended acicular ZnO structure can be synthesized via a hydrothermal process with tetramethylammonium hydroxide and zinc acetate as precursors and polyvinyl alcohol (PVA) as a structure-directing agent. The as-prepared ZnO products show the well crystalline wurtzite structure with growth direction along [0 0 0 1]. For the first time, PVA is found to be employed as a reservoir of Zn 2+ ions in the present study, and can control the concentration of Zn 2+ in reaction solution, and the acicular morphology can be formed at the two ends of the 1-D ZnO structure, due to the effect of secondary growth that occurs as the sufficient concentration of Zn 2+ ions chelated by PVA releasing to the reaction solution. Furthermore, the size of the 1-D ZnO structure can be tuned by different amounts of PVA addition.

  20. Novel functionally graded acicular electrode for solid oxide cells fabricated by the freeze-tape-casting process

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Bunch, Jacob; Li, Tingshuai; Mao, Zhengping; Chen, Fanglin

    2012-09-01

    The performance of electrode supported solid oxide cells is often limited by gas transport in the thick electrode support. In this study, a novel functionally graded acicular hydrogen electrode microstructure has been fabricated by the freeze-tape-casting method. The effects of freeze-tape-casting processing parameters such as solid loading, freezing bed temperature and tape pulling rate on the morphology of the hydrogen electrode support have been investigated. The electrochemical performance of the cells having the novel functionally graded acicular hydrogen electrode has been significantly improved. In the fuel cell mode, a high power output of 1.28 W cm-2 and a low polarization resistance of 0.166 Ω cm2 have been achieved at 800 °C with H2 as fuel and ambient air as oxidant using nickel-yttria-stabilized zirconia (YSZ) as the hydrogen electrode, YSZ as the electrolyte, and (La0.75Sr0.25)0.95MnO3-YSZ as the oxygen electrode. In the electrolysis mode, a high current density of 2.3 A cm-2 with 30 vol% absolute humidity in the hydrogen electrode at 800 °C has been achieved with an applied cell voltage of 1.6 V. It has been revealed that the novel acicular hydrogen electrode decreases the gas diffusion resistance, thus enhancing the cell performance.

  1. AFS controlling algorithm

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Jiang, Lanfang; Wang, Gengjie; Wang, Li

    2008-12-01

    Adaptive front lighting system (i.e., AFS) is the development trend of lighting system of motor vehicles. AFS means that headlamp can adjust beam direction to get best illumination according to road condition and its bodywork. The paper discusses the AFS key techniques: establishing calculation formulae of vehicle body state concerned road condition and steering state. Because of sensor technology limitations, it only can deal with inclination and turn of vehicle body state by means of sensor's signals. This paper studies the relationship between inclination and turn of the body and lamp lighting on the base of relative standards, and gives out the calculation formulae for the body and lamp lighting adjustment, also discusses its dynamical properties. The study is basic work for lighting adjustment automatically.

  2. Comminuting irradiated ferritic steel

    DOEpatents

    Bauer, Roger E.; Straalsund, Jerry L.; Chin, Bryan A.

    1985-01-01

    Disclosed is a method of comminuting irradiated ferritic steel by placing the steel in a solution of a compound selected from the group consisting of sulfamic acid, bisulfate, and mixtures thereof. The ferritic steel is used as cladding on nuclear fuel rods or other irradiated components.

  3. Cr-W-V bainitic/ferritic steel with improved strength and toughness and method of making

    DOEpatents

    Klueh, R.L.; Maziasz, P.J.

    1994-03-08

    This work describes a high strength, high toughness bainitic/ferritic steel alloy comprising about 2.75% to 4.0% chromium, about 2.0% to 3.5% tungsten, about 0.10% to 0.30% vanadium, and about 0.1% to 0.15% carbon with the balance iron, wherein the percentages are by total weight of the composition, wherein the alloy having been heated to an austenitizing temperature and then cooled at a rate sufficient to produce carbide-free acicular bainite. 15 figures.

  4. XXIst Century Ferrites

    NASA Astrophysics Data System (ADS)

    Mazaleyrat, F.; Zehani, K.; Pasko, A.; Loyau, V.; LoBue, M.

    2012-05-01

    Ferrites have always been a subject of great interest from point of view of magnetic application, since the fist compass to present date. In contrast, the scientific interest for iron based magnetic oxides decreased after Ørsted discovery as they where replaced by coil as magnetizing sources. Neel discovery of ferrimagnetism boosted again interest and leads to strong developments during two decades before being of less interest. Recently, the evolution of power electronics toward higher frequency, the downsizing of ceramics microstucture to nanometer scale, the increasing price of rare-earth elements and the development of magnetocaloric materials put light again on ferrites. A review on three ferrite families is given herein: harder nanostructured Ba2+Fe12O19 magnet processed by spark plasma sintering, magnetocaloric effect associated to the spin transition reorientation of W-ferrite and low temperature spark plasma sintered Ni-Zn-Cu ferrites for high frequency power applications.

  5. The use of nano-sized acicular material, sliding friction, and antisense DNA oligonucleotides to silence bacterial genes

    PubMed Central

    2014-01-01

    Viable bacterial cells impaled with a single particle of a nano-sized acicular material formed when a mixture containing the cells and the material was exposed to a sliding friction field between polystyrene and agar gel; hereafter, we refer to these impaled cells as penetrons. We have used nano-sized acicular material to establish a novel method for bacterial transformation. Here, we generated penetrons that carried antisense DNA adsorbed on nano-sized acicular material (α-sepiolite) by providing sliding friction onto the surface of agar gel; we then investigated whether penetron formation was applicable to gene silencing techniques. Antisense DNA was artificially synthesized as 15 or 90mer DNA oligonucleotides based on the sequences around the translation start codon of target mRNAs. Mixtures of bacterial cells with antisense DNA adsorbed on α-sepiolite were stimulated by sliding friction on the surface of agar gel for 60 s. Upon formation of Escherichia coli penetrons, β-lactamase and β-galactosidase expression was evaluated by counting the numbers of colonies formed on LB agar containing ampicillin and by measuring β-galactosidase activity respectively. The numbers of ampicillin resistant colonies and the β-galactosidase activity derived from penetrons bearing antisense DNA (90mer) was repressed to 15% and 25%, respectively, of that of control penetrons which lacked antisense DNA. Biphenyl metabolite, ring cleavage yellow compound produced by Pseudomonas pseudoalcaligenes penetron treated with antisense oligonucleotide DNA targeted to bphD increased higher than that lacking antisense DNA. This result indicated that expression of bphD in P. pseudoalcaligenes penetrons was repressed by antisense DNA that targeted bphD mRNA. Sporulation rates of Bacillus subtilis penetrons treated with antisense DNA (15mer) targeted to spo0A decreased to 24.4% relative to penetrons lacking antisense DNA. This novel method of gene silencing has substantial promise for

  6. Impedance calculation for ferrite inserts

    SciTech Connect

    Breitzmann, S.C.; Lee, S.Y.; Ng, K.Y.; /Fermilab

    2005-01-01

    Passive ferrite inserts were used to compensate the space charge impedance in high intensity space charge dominated accelerators. They study the narrowband longitudinal impedance of these ferrite inserts. they find that the shunt impedance and the quality factor for ferrite inserts are inversely proportional to the imaginary part of the permeability of ferrite materials. They also provide a recipe for attaining a truly passive space charge impedance compensation and avoiding narrowband microwave instabilities.

  7. Ferrite logic reliability study

    NASA Technical Reports Server (NTRS)

    Baer, J. A.; Clark, C. B.

    1973-01-01

    Development and use of digital circuits called all-magnetic logic are reported. In these circuits the magnetic elements and their windings comprise the active circuit devices in the logic portion of a system. The ferrite logic device belongs to the all-magnetic class of logic circuits. The FLO device is novel in that it makes use of a dual or bimaterial ferrite composition in one physical ceramic body. This bimaterial feature, coupled with its potential for relatively high speed operation, makes it attractive for high reliability applications. (Maximum speed of operation approximately 50 kHz.)

  8. Low activation ferritic alloys

    DOEpatents

    Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  9. Low activation ferritic alloys

    DOEpatents

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

    1985-02-07

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  10. Atrial Fibrillation (AF or AFib)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Atrial Fibrillation (AF or AFib) Updated:Feb 10,2016 What ... to the Terms and Conditions and Privacy Policy Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  11. Acicular photomultiplier photocathode structure

    DOEpatents

    Craig, Richard A.; Bliss, Mary

    2003-09-30

    A method and apparatus for increasing the quantum efficiency of a photomultiplier tube by providing a photocathode with an increased surface-to-volume ratio. The photocathode includes a transparent substrate, upon one major side of which is formed one or more large aspect-ratio structures, such as needles, cones, fibers, prisms, or pyramids. The large aspect-ratio structures are at least partially composed of a photoelectron emitting material, i.e., a material that emits a photoelectron upon absorption of an optical photon. The large aspect-ratio structures may be substantially composed of the photoelectron emitting material (i.e., formed as such upon the surface of a relatively flat substrate) or be only partially composed of a photoelectron emitting material (i.e., the photoelectron emitting material is coated over large aspect-ratio structures formed from the substrate material itself.) The large aspect-ratio nature of the photocathode surface allows for an effective increase in the thickness of the photocathode relative the absorption of optical photons, thereby increasing the absorption rate of incident photons, without substantially increasing the effective thickness of the photocathode relative the escape incidence of the photoelectrons.

  12. Pathogenesis of AF: Impact on intracardiac signals

    PubMed Central

    Shah, Ashok J; Dubois, Rémi; Miyazaki, Shinsuke; Jadidi, Amir S; Scherr, Daniel; Wilton, Stephen B; Roten, Laurent; Pascale, Patrizio; Pedersen, Michala; Derval, Nicolas; Knecht, Sebastien; Sacher, Frederic; Jais, Pierre; Narayan, Sanjiv; Hocini, Mélèze; Haïssaguerre, Michel

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia, and is responsible for the highest number of rhythm-related disorders and cardioembolic strokes worldwide. Intracardiac signal analysis during the onset of paroxysmal AF led to the discovery of pulmonary vein as a triggering source of AF, which has led to the development of pulmonary vein ablation—an established curative therapy for drug-resistant AF. Complex, multicomponent and rapid electrical activity widely involving the atrial substrate characterizes persistent/permanent AF. Widespread nature of the problem and complexity of signals in persistent AF reduce the success rate of ablation therapy. Although signal processing applied to extraction of relevant features from these complex electrograms has helped to improve the efficacy of ablation therapy in persistent/permanent AF, improved understanding of complex signals should help to identify sources of AF and further increase the success rate of ablation therapy. PMID:22255589

  13. High strength ferritic alloy

    DOEpatents

    Hagel, William C.; Smidt, Frederick A.; Korenko, Michael K.

    1977-01-01

    A high-strength ferritic alloy useful for fast reactor duct and cladding applications where an iron base contains from about 9% to about 13% by weight chromium, from about 4% to about 8% by weight molybdenum, from about 0.2% to about 0.8% by weight niobium, from about 0.1% to about 0.3% by weight vanadium, from about 0.2% to about 0.8% by weight silicon, from about 0.2% to about 0.8% by weight manganese, a maximum of about 0.05% by weight nitrogen, a maximum of about 0.02% by weight sulfur, a maximum of about 0.02% by weight phosphorous, and from about 0.04% to about 0.12% by weight carbon.

  14. Excimer laser ablation of ferrites

    NASA Astrophysics Data System (ADS)

    Tam, A. C.; Leung, W. P.; Krajnovich, D.

    1991-02-01

    Laser etching of ferrites was previously done by scanning a focused continuous-wave laser beam on a ferrite sample in a chemical environment. We study the phenomenon of photo-ablation of Ni-Zn or Mn-Zn ferrites by pulsed 248-nm KrF excimer laser irradiation. A transfer lens system is used to project a grating pattern of a mask irradiated by the pulsed KrF laser onto the ferrite sample. The threshold fluence for ablation at the ferrite surface is about 0.3 J/cm2. A typical fluence of 1 J/cm2 is used. The etched grooves produced are typically 20-50 μm wide, with depths achieved as deep as 70 μm . Groove straightness is good as long as a sharp image is projected onto the sample surface. The wall angle is steeper than 60 degrees. Scanning electron microscopy of the etched area shows a ``glassy'' skin with extensive microcracks and solidified droplets being ejected that is frozen in action. We found that this skin can be entirely removed by ultrasonic cleaning. A fairly efficient etching rate of about 10 nm/pulse for a patterned area of about 2 mm×2 mm is obtained at a fluence of 1 J/cm2. This study shows that projection excimer laser ablation is useful for micromachining of ferrite ceramics, and indicates that a hydrodynamic sputtering mechanism involving droplet emission is a cause of material removal.

  15. TiO2 decorated Co3O4 acicular nanotube arrays and its application as a non-enzymatic glucose sensor.

    PubMed

    Gao, Zhenfei; Zhang, Liqiang; Ma, Chi; Zhou, Qidong; Tang, Yushu; Tu, Zhiqiang; Yang, Wang; Cui, Lishan; Li, Yongfeng

    2016-06-15

    TiO2 modified Co3O4 acicular nanotube arrays (ANTAs) have been fabricated in this study, showing a good performance in glucose detection. In the experiment, the precursor Co(CO3)0.5(OH)·0.11H2O acicular nanowire arrays (ANWAs) was first grown on the fluorine doped tin oxide (FTO) substrate by a hydrothermal method. Thereafter, the uniform pink precursor Co(CO3)0.5(OH)·0.11H2O ANWAs was completely converted to the black Co3O4 ANTAs thin film by alkaline treatment. After the decoration of TiO2, the TiO2/Co3O4 ANTAs electrode exhibits a much higher current response to glucose compared with the Co3O4 ANTAs. Importantly, this neotype composite structure of Co3O4 enhances the glucose sensing performance by increasing specific surface area, additional reactive sites and synergistic effect, which make the TiO2/Co3O4 glucose sensor show a high sensitivity of 2008.82μAmM(-1)cm(-2), a fast response time (less than 5s) and a detection limit as low as 0.3396μM (S/N=3). The TiO2/Co3O4 ANTAs modified electrode exhibits a high selectivity for glucose in human serum, against ascorbic acid and uric acid. PMID:26890826

  16. Ferrite attenuator modulation improves antenna performance

    NASA Technical Reports Server (NTRS)

    Hooks, J. C.; Larson, S. G.; Shorkley, F. H.; Williams, B. T.

    1970-01-01

    Ferrite attenuator inserted into appropriate waveguide reduces the gain of the antenna element which is causing interference. Modulating the ferrite attenuator to change the antenna gain at the receive frequency permits ground tracking until the antenna is no longer needed.

  17. Effect of ferrite on cast stainless steels

    SciTech Connect

    Nadezhdin, A.; Cooper, K. ); Timbers, G. . Kraft Pulp Division)

    1994-09-01

    Premature failure of stainless steel castings in bleach washing service is attributed to poor casting quality high porosity and to a high ferrite content, which makes the castings susceptible to corrosion by hot acid chloride solutions. A survey of the chemical compositions and ferrite contents of corrosion-resistant castings in bleach plants at three pulp mills found high [delta]-ferrite levels in the austenitic matrix due to the improper balance between austenite and ferrite stabilizers.

  18. Articles comprising ferritic stainless steels

    DOEpatents

    Rakowski, James M.

    2016-06-28

    An article of manufacture comprises a ferritic stainless steel that includes a near-surface region depleted of silicon relative to a remainder of the ferritic stainless steel. The article has a reduced tendency to form an electrically resistive silica layer including silicon derived from the steel when the article is subjected to high temperature oxidizing conditions. The ferritic stainless steel is selected from the group comprising AISI Type 430 stainless steel, AISI Type 439 stainless steel, AISI Type 441 stainless steel, AISI Type 444 stainless steel, and E-BRITE.RTM. alloy, also known as UNS 44627 stainless steel. In certain embodiments, the article of manufacture is a fuel cell interconnect for a solid oxide fuel cell.

  19. High power ferrite microwave switch

    NASA Technical Reports Server (NTRS)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  20. Small high directivity ferrite antennas

    NASA Astrophysics Data System (ADS)

    Wright, T. M. B.

    A centimeter-wavelength antenna of millimetric dimensions, which uses the intrinsic angular sensitivity of ferrites, is described, with an emphasis on the modification of the material's permeability. The construction of both the ferrite film lens antenna and the ferrite film cassegrain antenna are detailed; both can be devised in a number of configurations for appropriate beam positioning and rf filtering. The antenna design, discussed primarily in the context of smart missiles, electronic warfare, and satellite systems, presents the possibility of magnetically switching between the transmit and receive modes within the antenna structure itself. Finally, it is noted that for a simple 2-dipole array the angular resolution can be two orders of magnitude higher than with the conventional techniques.

  1. Modeling C-Curves for the Growth Rate of Widmanstätten and Bainitic Ferrite in Fe-C Alloys

    NASA Astrophysics Data System (ADS)

    Leach, Lindsay; Hillert, Mats; Borgenstam, Annika

    2016-01-01

    When Zener formulated his maximum growth rate criterion for predicting the coarseness of various metallographic objects, he simplified the growth rate equations and predicted that the optimum coarseness should be twice the critical value for which all the driving force would be absorbed by interfacial energy. It is now emphasized that a composition dependence of the diffusion coefficient has a considerable influence and can result in a ratio much larger than two. Various approximations have now been removed from the growth rate equation. When applied to acicular ferrite in the Fe-C system, a C-curve for the growth rate is obtained that resembles the unusually wide C-curve obtained experimentally when information on Widmanstätten ferrite and bainite is combined. It is not necessary to explain that shape as a combination of separate curves for Widmanstätten ferrite and bainite. The main reason for the wide C-curve is the direct effect of the composition dependence of the diffusivity of carbon in austenite.

  2. Study about AFS swerve mode

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Jiang, Lanfang; Zhao, Qin; Wang, Li

    2009-11-01

    A swerving mathematical model was established after stating the shortage of the present AFS swerving algorithm. The conception of 'expected lighting distance' was extended to 'expected lighting bound' and approximate treatment of geometry of light beam falling to ground of headlamp was processed. The expected lighting bound was ascertained and the lighting range of turning angle of headlamp was calculated. The calculation formula of turning angle of headlamp was worked out. It was indicated that the turning angle of inside and outside of headlamp calculated by revised algorithm was reasonable by comparing calculation. Finally the control strategy about the turning angle of inside and outside headlamp when turning was worked out. It is of practical significance in promoting the active safety, reducing the traffic accidents caused by insufficient angle and range of irradiation of headlamp.

  3. Eaton AF5000+Genesis Communication Driver

    1995-05-25

    Communication driver allows the Genesis Control Series software to interact with Eaton AF5000+ frequency drives via RS-232 communications. All Eaton AF5000+ parameters that support communications are supported by the Genesis driver. Multidrop addressing to multiple units is available with the Genesis communication driver.

  4. Multiferroic bismuth ferrite material core based inductive displacement sensor

    NASA Astrophysics Data System (ADS)

    Rajeswari, R.; Biswal, M. R.; Nanda, J.; Mishra, N. C.

    2012-07-01

    In this research, an inductive displacement sensor with multiferroic bismuth ferrite core has been realized. The bismuth ferrite sample is synthesized and its structural and dielectric properties are studied. A rod-shaped bismuth ferrite core is prepared and displaced through the inductor of a RLC circuit. The performance of the prepared bismuth ferrite core has been compared with a commercially available ferrite core.

  5. Development of a monolithic ferrite memory array

    NASA Technical Reports Server (NTRS)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  6. Magnetocaloric effect in ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Poddar, P.; Gass, J.; Rebar, D. J.; Srinath, S.; Srikanth, H.; Morrison, S. A.; Carpenter, E. E.

    2006-12-01

    A comparative study of the magnetocaloric effect (MCE) is reported in two different types of chemically synthesized magnetic nanoparticle systems—cobalt ferrite and manganese zinc ferrite with mean size around 5 and 15 nm, respectively. While CoFe 2O 4 nanoparticles were synthesized using co-precipitation, the Mn 0.68Zn 0.25Fe 2.07O 4 (MZFO) nanoparticles were prepared by reverse micelle technique using AOT as surfactant. Our results indicate that the change in entropy with the change in applied magnetic field (d S/d H) is reasonably large for this class of nanoparticles and has a wide distribution over a broad temperature range covering the region above and below the blocking temperature. The maximum entropy change is influenced by the particle size, overall distribution in anisotropy and magnetic moments.

  7. Irradiation effects in ferritic steels

    NASA Astrophysics Data System (ADS)

    Lechtenberg, Thomas

    1985-08-01

    Since 1979 the Alloy Development for Irradiation Performance (ADIP) task funded by the US Department of Energy has been studying the 2-12Cr class of ferritic steels to establish the feasibility of using them in fusion reactor first wall/breeding blanket (FW/B) applications. The advantages of ferritic steels include superior swelling resistance, low thermal stresses compared to austenitic stainless steels, attractive mechanical properties up to 600°C. and service histories exceeding 100 000 h. These steels are commonly used in a range of microstructural conditions which include ferritic, martensitic. tempered martensitic, bainitic etc. Throughout this paper where the term "ferritic" is used it should be taken to mean any of these microstructures. The ADIP task is studying several candidate alloy systems including 12Cr-1MoWV (HT-9), modified 9Cr-1MoVNb, and dual-phased steels such as EM-12 and 2 {1}/{4}Cr-Mo. These materials are ferromagnetic (FM), body centered cubic (bcc), and contain chromium additions between 2 and 12 wt% and molybdenum additions usually below 2%. The perceived issues associated with the application of this class of steel to fusion reactors are the increase in the ductile-brittle transition temperature (DBTT) with neutron damage, the compatibility of these steels with liquid metals and solid breeding materials, and their weldability. The ferromagnetic character of these steels can also be important in reactor design. It is the purpose of this paper to review the current understanding of these bcc steels and the effects of irradiation. The major points of discussion will be irradiation-induced or -enhanced dimensional changes such as swelling and creep, mechanical properties such as tensile strength and various measurements of toughness, and activation by neutron interactions with structural materials.

  8. Multifunctionality of nanocrystalline lanthanum ferrite

    NASA Astrophysics Data System (ADS)

    Rai, Atma; Thakur, Awalendra K.

    2016-05-01

    Nanocrystalline lanthanum ferrite has been synthesized by adopting modified Pechini route. No evidence of impurity or secondary phase has been detected up to the detection of error limit of X-ray diffractometer (XRD). Rietveld refinement of X-ray diffraction pattern reveals orthorhombic crystal system with space group Pnma (62).Crystallite size and lattice strain was found to be ˜42.8nm and 0.306% respectively. Optical band gap was found to be 2.109 eV, by UV-Visible diffused reflectance spectrum (DRS). Brunauer-Emmet-Teller (BET) surface area was found to be ˜3.45 m2/g. Magnetization-hysteresis (M-H) loop was recorded at room temperature (300K) reveals weak ferromagnetism in Nanocrystalline lanthanum ferrite. The weak ferromagnetism in lanthanum ferrite is due to the uncompensated antiferromagnetic spin ordering. Ferroelectric loop hysteresis observed at room temperature at 100Hz depicts the presence of ferroelectric ordering in LaFeO3.Simultanious presence of magnetic and ferroelectric ordering at room temperature makes it suitable candidate of Multiferroic family.

  9. STBC AF relay for unmanned aircraft system

    NASA Astrophysics Data System (ADS)

    Adachi, Fumiyuki; Miyazaki, Hiroyuki; Endo, Chikara

    2015-01-01

    If a large scale disaster similar to the Great East Japan Earthquake 2011 happens, some areas may be isolated from the communications network. Recently, unmanned aircraft system (UAS) based wireless relay communication has been attracting much attention since it is able to quickly re-establish the connection between isolated areas and the network. However, the channel between ground station (GS) and unmanned aircraft (UA) is unreliable due to UA's swing motion and as consequence, the relay communication quality degrades. In this paper, we introduce space-time block coded (STBC) amplify-and-forward (AF) relay for UAS based wireless relay communication to improve relay communication quality. A group of UAs forms single frequency network (SFN) to perform STBC-AF cooperative relay. In STBC-AF relay, only conjugate operation, block exchange and amplifying are required at UAs. Therefore, STBC-AF relay improves the relay communication quality while alleviating the complexity problem at UAs. It is shown by computer simulation that STBC-AF relay can achieve better throughput performance than conventional AF relay.

  10. Exchange coupled ferrite nanocomposites through chemical synthesis.

    PubMed

    Dai, Qilin; Patel, Ketan; Ren, Shenqiang

    2016-08-16

    Exchange coupling between magnetically hard and soft phases has the potential to yield a large gain in the energy product. In this work, we present a scalable chemical synthetic route to produce magnetic iron oxide based nanocomposites, consisting of cobalt ferrite (CoFe2O4) and strontium ferrite (SrFe12O19) components. PMID:27476744

  11. Abnormal ferrite in hyper-eutectoid steels

    SciTech Connect

    Chairuangsri, T.; Edmonds, D.V.

    2000-04-19

    The microstructural characteristics of ultra-high carbon hyper-eutectoid Fe-C and Fe-C-Cu experimental steels have been examined after isothermal transformation in a range just beneath the eutectoid temperature. Particular attention was paid to the formation of so-called abnormal ferrite, which refers to coarse ferrite grains which can form, in hyper-eutectoid compositions, on the pro-eutectoid cementite before the pearlite reaction occurs. Thus it is confirmed that the abnormal ferrite is not a result of pearlite coarsening, but of austenite decomposition before the conditions for coupled growth of pearlite are established. The abnormal ferrite formed on both allotriomorphic and Widmanstaetten forms of pro-eutectoid cementite, and significantly, it was observed that the pro-eutectoid cementite continued to grow, despite being enclosed by the abnormal ferrite. Under certain conditions this could lead to the eventual formation of substantially reduced amounts of pearlite. Thus, a model for carbon redistribution that allows the proeutectoid cementite to thicken concurrently with the abnormal ferrite is presented. The orientation relationships between the abnormal ferrite and pro-eutectoid cementite were also determined and found to be close to those which have been reported between pearlitic ferrite and pearlitic cementite.

  12. Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success

    PubMed Central

    Choi, Eue-Keun; Park, Jae Hyung; Lee, Ji-Young; Nam, Chung Mo; Hwang, Min Ki; Uhm, Jae-Sun; Joung, Boyoung; Ko, Young-Guk; Lee, Moon-Hyoung; Lubitz, Steven A; Ellinor, Patrick T; Pak, Hui-Nam

    2015-01-01

    Background Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (PITX2), 16q22 (ZFHX3), and 1q21 (KCNN3) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF. Methods and Results We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age- and sex-matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF (PITX2/rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P=1.32×10−16; PITX2/rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P=2.20×10−11; ZFHX3/rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P=3.75×10−14; KCNN3/rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P=0.085). Among those patients who underwent catheter ablation for AF, none of the top AF-associated SNPs were associated with long-term clinical recurrence of AF after catheter ablation. Conclusions SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF-susceptibility SNPs predicted clinical recurrence after catheter ablation. PMID:26272656

  13. Delta ferrite in the weld metal of reduced activation ferritic martensitic steel

    NASA Astrophysics Data System (ADS)

    Sam, Shiju; Das, C. R.; Ramasubbu, V.; Albert, S. K.; Bhaduri, A. K.; Jayakumar, T.; Rajendra Kumar, E.

    2014-12-01

    Formation of delta(δ)-ferrite in the weld metal, during autogenous bead-on-plate welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the weld metal revealed presence of delta-ferrite in the weld metal. Volume fraction of delta-ferrite is found to be higher in the weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during welding affects the volume fraction of delta-ferrite retained in the weld metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the weld metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid metal to the ambient temperature. This manuscript will discuss the effect of welding parameters on formation of delta-ferrite and its retention in the weld metal of RAFM steel.

  14. Structural analysis of emerging ferrite: Doped nickel zinc ferrite

    SciTech Connect

    Kumar, Rajinder; Kumar, Hitanshu; Singh, Ragini Raj; Barman, P. B.

    2015-08-28

    Ni{sub 0.6-x}Zn{sub 0.4}Co{sub x}Fe{sub 2}O{sub 4} (x = 0, 0.033, 0.264) nanoparticles were synthesized by sol-gel method and annealed at 900°C. Structural properties of all prepared samples were examined with X-ray diffraction (XRD). The partial formation of hematite (α-Fe{sub 2}O{sub 3}) secondary phase with spinel phase cubic structure of undoped and cobalt doped nickel zinc ferrite was found by XRD peaks. The variation in crystallite size and other structural parameters with cobalt doping has been calculated for most prominent peak (113) of XRD and has been explained on the basis of cations ionic radii difference.

  15. Degradation of AF1Q by chaperone-mediated autophagy

    SciTech Connect

    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru; Li, Huanjie; Cui, Taixing; Li Wang, Xing; Tang, Dongqi; Ji, Chunyan

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  16. AFS Estuaries Section - A Successful Partnership

    EPA Science Inventory

    The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

  17. Ferrite Nanoparticles in Pharmacological Modulation of Angiogenesis

    NASA Astrophysics Data System (ADS)

    Deshmukh, Aparna; Radha, S.; Khan, Y.; Tilak, Priya

    2011-07-01

    Nanoparticles are being explored in the targeted drug delivery of pharmacological agents : angiogenesis being one such novel application which involves formation of new blood vessels or branching of existing ones. The present study involves the use of ferrite nanoparticles for precise therapeutic modulation of angiogenesis. The ferrite nanoparticles synthesized by co-precipitation of ferrous and ferric salts by a suitable base, were found to be 10-20 nm from X-ray diffraction and TEM measurements. The magnetization measurements showed superparamagnetic behavior of the uncoated nanoparticles. These ferrite nanoparticles were found to be bio-compatible with lymphocytes and neural cell lines from the biochemical assays. The chick chorioallantoic membrane(CAM) from the shell of fertile white Leghorn eggs was chosen as a model to study angiogenic activity. An enhancement in the angiogenic activity in the CAM due to addition of uncoated ferrite nanoparticles was observed.

  18. ALL-FERRITE RHIC INJECTION KICKER

    SciTech Connect

    HAHN,H.; FISCHER,W.; PTITSYN,V.I.; TUOZZOLO,J.E.

    2001-06-18

    Ion beams are transferred from the AGS into RHIC in boxcar fashion as single bunches. The nominal design assumes 60 bunches per ring but increasing the number of bunches to gain luminosity is possible, thereby requiring injection kickers with a shorter rise time. The original injection system consists of traveling-wave dielectric loaded kicker magnets and a Blumlein pulser with a rise time adequate for the present operation. Voltage breakdown in the dielectric kickers suggested the use of all-ferrite magnets. In order to minimize the conversion cost, the design of the all-ferrite kicker uses the same components as the dielectric loaded units. The all-ferrite kickers showed in bench measured good breakdown properties and a current rise time of < 50 ns. A prototype kicker has been installed in the blue ring and was tested with beam. Beam measurements indicate suitability of all-ferrite kicker magnets for upgraded operation.

  19. Ferrite HOM Absorber for the RHIC ERL

    SciTech Connect

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  20. Health Information in Somali (af Soomaali): MedlinePlus

    MedlinePlus

    ... af Soomaali (Somali) Bilingual PDF Health Information Translations Animal Bites Animal Bites and Scratches Qaniinyada iyo Xagashada Xayawaanka - af ... Soomaali (Somali) Bilingual PDF Health Information Translations Radiation Therapy Preventing Infections When Your White Blood Cell Count ...

  1. Health Information in Somali (af Soomaali): MedlinePlus

    MedlinePlus

    ... Bilingual PDF Health Information Translations Appendectomy for a Child Qabsin-saarid ilmo - af Soomaali (Somali) Bilingual PDF ... Somali) Bilingual PDF Health Information Translations Asthma in Children Nebulizer Treatments Daawenta wal in Xaqiiqsanaan - af Soomaali ( ...

  2. Ferrite insertion at Recycler Flying Wire System

    SciTech Connect

    K.Y. Ng

    2004-02-27

    Ferrite rods are installed inside the flying-wire cavity of the Recycler Ring and at entrance and exit beam pipes in order to absorb high-frequency electromagnetic waves excited by the beam. However, these rods may also deteriorate the vacuum pressure of the ring. An investigation is made to analyze the necessity of the ferrite rods at the entrance and exit beam pipes.

  3. Microfluidic Pumps Containing Teflon [Trademark] AF Diaphragms

    NASA Technical Reports Server (NTRS)

    Willis, Peter; White, Victor; Grunthaner, Frank; Ikeda, Mike; Mathies, Richard A.

    2009-01-01

    Microfluidic pumps and valves based on pneumatically actuated diaphragms made of Teflon AF polymers are being developed for incorporation into laboratory-on-a-chip devices that must perform well over temperature ranges wider than those of prior diaphragm-based microfluidic pumps and valves. Other potential applications include implanted biomedical microfluidic devices, wherein the biocompatability of Teflon AF polymers would be highly advantageous. These pumps and valves have been demonstrated to function stably after cycling through temperatures from -125 to 120 C. These pumps and valves are intended to be successors to similar prior pumps and valves containing diaphragms made of polydimethylsiloxane (PDMS) [commonly known as silicone rubber]. The PDMS-containing valves ae designed to function stably only within the temperature range from 5 to 80 C. Undesirably, PDMS membranes are somwehat porous and retain water. PDMS is especially unsuitable for use at temperatures below 0 C because the formation of ice crystals increases porosity and introduces microshear.

  4. Residual ferrite formation in 12CrODS steels

    NASA Astrophysics Data System (ADS)

    Ukai, S.; Kudo, Y.; Wu, X.; Oono, N.; Hayashi, S.; Ohtsuka, S.; Kaito, T.

    2014-12-01

    Increasing Cr content from 9 to 12 mass% leads to superior corrosion and high-temperature oxidation resistances, and usually changes microstructure from martensite to a ferrite. To make transformable martensitic type of 12CrODS steels that have superior processing capability by using α/γ phase transformation, alloy design was conducted through varying nickel content. The structure of 12CrODS steels was successfully modified from full ferrite to a transformable martensite-base matrix containing ferrite. This ferrite consists of both equilibrium ferrite and a metastable residual ferrite. It was shown that the fraction of the equilibrium ferrite is predictable by computed phase diagram and formation of the residual ferrite was successfully evaluated through pinning of α/γ interfacial boundaries by oxide particles.

  5. Magnetocaloric effect in ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Rebar, D.

    2005-03-01

    Miniaturization of the electronic devices for space, military and consumer applications requires cooling devices to be fabricated on a chip for power efficient, noise-free operations. Refrigeration based on the adiabatic-demagnetization has been used for several decades for cooling down to sub-kelvin temperatures. Superparamagnetic particles also hold tremendous potential towards this application. We have studied magnetocaloric effect (MCE) properties in chemically synthesized ferrite nanoparticles over a broad range in temperature and magnetic fields. Nanoparticles investigated include Fe3O4 (average size = 8 nm, synthesized using co-precipitation method), MnZnFe2O4 (average size = 15 nm, synthesized using reverse-micelle technique) and CoFe2O4 (average size 8 nm, synthesized using pyrolectic technique). The magnetic entropy change was calculated by applying Maxwell's relations to magnetization vs magnetic field curves at various temperatures. Our results indicate that the single-domain particles in their superparamagnetic state show a considerable entropy change near the blocking temperature. The influence of interactions on MCE effect will also be discussed. Work supported by NSF through Grant No. CTS-0408933

  6. Rapid phase synthesis of nanocrystalline cobalt ferrite

    SciTech Connect

    Shanmugavel, T.; Raj, S. Gokul; Rajarajan, G.; Kumar, G. Ramesh

    2014-04-24

    Synthesis of single phase nanocrystalline Cobalt Ferrite (CoFe{sub 2}O{sub 4}) was achieved by single step autocombustion technique with the use of citric acid as a chelating agent in mono proportion with metal. Specimens prepared with this method showed significantly higher initial permeability's than with the conventional process. Single phase nanocrystalline cobalt ferrites were formed at very low temperature. Surface morphology identification were carried out by transmission electron microscopy (TEM) analysis. The average grain size and density at low temperature increased gradually with increasing the temperature. The single phase formation is confirmed through powder X-ray diffraction analysis. Magnetization measurements were obtained at room temperature by using a vibrating sample magnetometer (VSM), which showed that the calcined samples exhibited typical magnetic behaviors. Temperature dependent magnetization results showed improved behavior for the nanocrystalline form of cobalt ferrite when compared to the bulk nature of materials synthesized by other methods.

  7. Excimer laser ablation of ferrite ceramics

    NASA Astrophysics Data System (ADS)

    Tam, A. C.; Leung, W. P.; Krajnovich, D.

    We study the ablation of Ni-Zn or Mn-7n ferrites by 248-nm KrF excimer laser irradiation for high-resolution patterning. A transfer lens system is used to project the image of a mask irradiated by the pulsed KrF laser onto the ferrite sample. The threshold fluente for ablation of the ferrite surface is about 0.3 J/cm2. A typical fluente of 1 J/cm2 is used to produce good-quality patterning. Scanning electron microscopy of the ablated area shows a "glassy" skin with extensive microcracks and solidified droplets being ejected that is frozen in action. This skin can be removed by ultrasonic cleaning.

  8. Cation distributions on rapidly solidified cobalt ferrite

    NASA Technical Reports Server (NTRS)

    De Guire, Mark R.; Kalonji, Gretchen; O'Handley, Robert C.

    1990-01-01

    The cation distributions in two rapidly solidified cobalt ferrites have been determined using Moessbauer spectroscopy at 4.2 K in an 8-T magnetic field. The samples were obtained by gas atomization of a Co0-Fe2O3-P2O5 melt. The degree of cation disorder in both cases was greater than is obtainable by cooling unmelted cobalt ferrite. The more rapidly cooled sample exhibited a smaller departure from the equilibrium cation distribution than did the more slowly cooled sample. This result is explained on the basis of two competing effects of rapid solidification: high cooling rate of the solid, and large undercooling.

  9. Development of Lanthanum Ferrite SOFC Cathodes

    SciTech Connect

    Simner, Steve P.; Bonnett, Jeff F.; Canfield, Nathan L.; Meinhardt, Kerry D.; Shelton, Jayne P.; Sprenkle, Vince L.; Stevenson, Jeffry W.

    2003-01-01

    A number of studies have been conducted concerning compositional/microstructural modifications of a Sr-doped lanthanum ferrite (LSF) cathode and protective Sm-doped ceria (SDC) layer in an anode supported solid oxide fuel cell (SOFC). Emphasis was placed on achieving enhanced low temperature (700-800 degrees C) performance, and long-term cell stability. Investigations involved manipulation of the lanthanum ferrite chemistry, addition of noble metal oxygen reduction catalysts, incorporation of active cathode layer compositions containing Co, Fe and higher Sr contents, and attempts to optimize the ceria barrier layer between the LSF cathode and YSZ electrolyte.

  10. A preliminary ferritic-martensitic stainless steel constitution diagram

    SciTech Connect

    Balmforth, M.C.; Lippold, J.C.

    1998-01-01

    This paper describes preliminary research to develop a constitution diagram that will more accurately predict the microstructure of ferritic and martensitic stainless steel weld deposits. A button melting technique was used to produce a wide range of compositions using mixtures of conventional ferritic and martensitic stainless steels, including types 403, 409, 410, 430, 439 and 444. These samples were prepared metallographically, and the vol-% ferrite and martensite was determined quantitatively. In addition, the hardness and ferrite number (FN) were measured. Using this data, a preliminary constitution diagram is proposed that provides a more accurate method for predicting the microstructures of arc welds in ferritic and martensitic stainless steels.

  11. 4:2:1 conduction of an AF initiating trigger

    PubMed Central

    Kojodjojo, Pipin; Chong, Eric; Lim, Toon Wei; Seow, Swee Chong

    2015-01-01

    A 44 year old male with idiopathic dilated cardiomyopathy was undergoing persistent atrial fibrillation (AF) ablation. Following antral ablation, AF terminated into a regular narrow complex rhythm. Earliest activation was mapped to a focus in the superior vena cava (SVC) which was conducted in a 2:1 ratio to the atria which in turn was conducted with 2:1 ratio to the ventricles, resulting in an unusual 4:2:1 conduction of the SVC tachycardia. 1:1 conduction of the SVC tachycardia to the atrium preceded initiation of AF. During AF, SVC tachycardia continued unperturbed. Sinus rhythm was restored following catheter ablation of the focus. PMID:27134438

  12. Thermodynamic studies on lithium ferrites

    SciTech Connect

    Rakshit, S.K.; Parida, S.C.; Naik, Y.P.; Chaudhary, Ziley Singh; Venugopal, V.

    2011-05-15

    Thermodynamic studies on ternary oxides of Li-Fe-O systems were carried out using differential scanning calorimetry, Knudsen effusion mass spectrometry, and solid-state electrochemical technique based on fluoride electrolyte. Heat capacities of LiFe{sub 5}O{sub 8}(s) and LiFeO{sub 2}(s) were determined in the temperature range 127-861 K using differential scanning calorimetry. Gibbs energies of formation of LiFe{sub 5}O{sub 8}(s) and LiFeO{sub 2}(s) were determined using Knudsen effusion mass spectrometry and solid-state galvanic cell technique. The combined least squares fits can be represented as {Delta}{sub f}G{sub m}{sup o}(LiFe{sub 5}O{sub 8},s,T)/kJ mol{sup -1} ({+-}6)=-2341+0.6764(T/K) (588{<=}T/K{<=}971) {Delta}{sub f}G{sub m}{sup o}(LiFeO{sub 2},s,T)/kJ mol{sup -1} ({+-}3)=-708+0.1656(T/K) (569{<=}T/K{<=}1021) The temperature independent term of the above equations represents {Delta}{sub f}H{sup o}{sub m}(T{sub av}) and temperature dependent term represents negative change in entropy of the respective compounds. Thermodynamic analysis shows that LiFe{sub 5}O{sub 8}(s) is more stable compared to LiFeO{sub 2}(s). -- Graphical abstract: Comparison of {Delta}{sub f}G{sub m}{sup o}(T) of lithium ferrites determined using different techniques. Display Omitted Highlights: {yields} Thermodynamic studies on Li-Fe-O system using DSC, KEQMS and galvanic cell. {yields} Heat capacities of LiFe{sub 5}O{sub 8}(s) and LiFeO{sub 2}(s) were determined using DSC 127-861 K. {yields} {Delta}{sub f}G{sup o}{sub m} of these compounds were determined and compared. {yields} Thermodynamic tables for LiFe{sub 5}O{sub 8}(s) and LiFeO{sub 2}(s) were constructed.

  13. Contact material for pressure-sintering ferrites

    NASA Technical Reports Server (NTRS)

    Wentworth, C.

    1970-01-01

    Pressure-sintering, in which the unfired laminated ferrite plane is placed between two flat punches and pressed during firing, reduces lateral firing shrinkage to less than one percent. A decrease in thickness of the laminate produces the required volume shrinkage. Phlogopite is the most suitable contact material investigated.

  14. Adding calcium improves lithium ferrite core

    NASA Technical Reports Server (NTRS)

    Lessoff, H.

    1969-01-01

    Adding calcium increases uniformity of grain growth over a wide range of sintering temperatures and reduces porosity within the grain. Ferrite cores containing calcium have square hysteresis loops and high curie temperatures, making them useful in coincident current memories of digital electronic computers.

  15. Tantalum modified ferritic iron base alloys

    NASA Technical Reports Server (NTRS)

    Oldrieve, R. E.; Blankenship, C. P. (Inventor)

    1977-01-01

    Strong ferritic alloys of the Fe-CR-Al type containing 0.4% to 2% tantalum were developed. These alloys have improved fabricability without sacrificing high temperature strength and oxidation resistance in the 800 C (1475 F) to 1040 C (1900 F) range.

  16. Effect of ferrite addition above the base ferrite on the coupling factor of wireless power transfer for vehicle applications

    NASA Astrophysics Data System (ADS)

    Batra, T.; Schaltz, E.; Ahn, S.

    2015-05-01

    Power transfer capability of wireless power transfer systems is highly dependent on the magnetic design of the primary and secondary inductors and is measured quantitatively by the coupling factor. The inductors are designed by placing the coil over a ferrite base to increase the coupling factor and reduce magnetic emissions to the surroundings. Effect of adding extra ferrite above the base ferrite at different physical locations on the self-inductance, mutual inductance, and coupling factor is under investigation in this paper. The addition can increase or decrease the mutual inductance depending on the placement of ferrite. Also, the addition of ferrite increases the self-inductance of the coils, and there is a probability for an overall decrease in the coupling factor. Correct placement of ferrite, on the other hand, can increase the coupling factor relatively higher than the base ferrite as it is closer to the other inductor. Ferrite being a heavy compound of iron increases the inductor weight significantly and needs to be added judiciously. Four zones have been identified in the paper, which shows different sensitivity to addition of ferrite in terms of the two inductances and coupling factor. Simulation and measurement results are presented for different air gaps between the coils and at different gap distances between the ferrite base and added ferrite. This paper is beneficial in improving the coupling factor while adding minimum weight to wireless power transfer system.

  17. AF4 and AF4N protein complexes: recruitment of P-TEFb kinase, their interactome and potential functions

    PubMed Central

    Scholz, Bastian; Kowarz, Eric; Rössler, Tanja; Ahmad, Khalil; Steinhilber, Dieter; Marschalek, Rolf

    2015-01-01

    AF4/AFF1 and AF5/AFF4 are the molecular backbone to assemble “super-elongation complexes” (SECs) that have two main functions: (1) control of transcriptional elongation by recruiting the positive transcription elongation factor b (P-TEFb = CyclinT1/CDK9) that is usually stored in inhibitory 7SK RNPs; (2) binding of different histone methyltransferases, like DOT1L, NSD1 and CARM1. This way, transcribed genes obtain specific histone signatures (e.g. H3K79me2/3, H3K36me2) to generate a transcriptional memory system. Here we addressed several questions: how is P-TEFb recruited into SEC, how is the AF4 interactome composed, and what is the function of the naturally occuring AF4N protein variant which exhibits only the first 360 amino acids of the AF4 full-length protein. Noteworthy, shorter protein variants are a specific feature of all AFF protein family members. Here, we demonstrate that full-length AF4 and AF4N are both catalyzing the transition of P-TEFb from 7SK RNP to their N-terminal domain. We have also mapped the protein-protein interaction network within both complexes. In addition, we have first evidence that the AF4N protein also recruits TFIIH and the tumor suppressor MEN1. This indicate that AF4N may have additional functions in transcriptional initiation and in MEN1-dependend transcriptional processes. PMID:26171280

  18. Differential cytotoxicity of copper ferrite nanoparticles in different human cells.

    PubMed

    Ahmad, Javed; Alhadlaq, Hisham A; Alshamsan, Aws; Siddiqui, Maqsood A; Saquib, Quaiser; Khan, Shams T; Wahab, Rizwan; Al-Khedhairy, Abdulaziz A; Musarrat, Javed; Akhtar, Mohd Javed; Ahamed, Maqusood

    2016-10-01

    Copper ferrite nanoparticles (NPs) have the potential to be applied in biomedical fields such as cell labeling and hyperthermia. However, there is a lack of information concerning the toxicity of copper ferrite NPs. We explored the cytotoxic potential of copper ferrite NPs in human lung (A549) and liver (HepG2) cells. Copper ferrite NPs were crystalline and almost spherically shaped with an average diameter of 35 nm. Copper ferrite NPs induced dose-dependent cytotoxicity in both types of cells, evident by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide and neutral red uptake assays. However, we observed a quite different susceptibility in the two kinds of cells regarding toxicity of copper ferrite NPs. Particularly, A549 cells showed higher susceptibility against copper ferrite NP exposure than those of HepG2 cells. Loss of mitochondrial membrane potential due to copper ferrite NP exposure was observed. The mRNA level as well as activity of caspase-3 enzyme was higher in cells exposed to copper ferrite NPs. Cellular redox status was disturbed as indicated by induction of reactive oxygen species (oxidant) generation and depletion of the glutathione (antioxidant) level. Moreover, cytotoxicity induced by copper ferrite NPs was efficiently prevented by N-acetylcysteine treatment, which suggests that reactive oxygen species generation might be one of the possible mechanisms of cytotoxicity caused by copper ferrite NPs. To the best of our knowledge, this is the first report showing the cytotoxic potential of copper ferrite NPs in human cells. This study warrants further investigation to explore the mechanisms of differential toxicity of copper ferrite NPs in different types of cells. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26918645

  19. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 14 2013-01-01 2013-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  20. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 14 2012-01-01 2012-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  1. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  2. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  3. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 14 2014-01-01 2014-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  4. Part III: AFS - A Secure Distributed File System

    SciTech Connect

    Wachsmann, A.; /SLAC

    2005-06-29

    AFS is a secure distributed global file system providing location independence, scalability and transparent migration capabilities for data. AFS works across a multitude of Unix and non-Unix operating systems and is used at many large sites in production for many years. AFS still provides unique features that are not available with other distributed file systems even though AFS is almost 20 years old. This age might make it less appealing to some but with IBM making AFS available as open-source in 2000, new interest in use and development was sparked. When talking about AFS, people often mention other file systems as potential alternatives. Coda (http://www.coda.cs.cmu.edu/) with its disconnected mode will always be a research project and never have production quality. Intermezzo (http://www.inter-mezzo.org/) is now in the Linux kernel but not available for any other operating systems. NFSv4 (http://www.nfsv4.org/) which picked up many ideas from AFS and Coda is not mature enough yet to be used in serious production mode. This article presents the rich features of AFS and invites readers to play with it.

  5. Toward a petabyte-scale AFS service at CERN

    NASA Astrophysics Data System (ADS)

    van der Ster, Daniel; Moscicki, Jakub T.; Wiebalck, Arne

    2014-06-01

    AFS is a mature and reliable storage service at CERN, having worked for more than 20 years as the provider of Unix home directories and project areas. Recently, the AFS service has grown at unprecedented rates (200% in the past year); this growth was unlocked thanks to innovations in both the hardware and software components of our file servers. This work presents how AFS is used at CERN and how the service offering is evolving with the increasing storage needs of its local and remote user communities. In particular, we demonstrate the usage patterns for home directories, workspaces and project spaces, as well as show the daily work which is required to rebalance data and maintaining stability and performance. Finally, we highlight some recent changes and optimisations made to the AFS Service, thereby revealing how AFS can possibly operate at all while being subjected to frequent-almost DDOS-like-attacks from its users.

  6. Design of ferrite-tuned accelerator cavities using perpendicular-biased high-Q ferrites

    SciTech Connect

    Kaspar, K.

    1984-11-01

    Microwave ferrites with dc bias fields perpendicular to the rf fields exhibit magnetic and dielectric quality factors 1 order of magnitude above that of ferrites used in ferrite-tuned synchrotron accelerating cavities built in the past. For the LAMPF II project, these ferrites appear to allow the design of synchrotron cavities with high gap voltages and high efficiency. A simple coaxial quarter-wave-resonator geometry, first considered only as a model for preliminary studies, turned out to be a good basis for the solution of most technical problems such as generation of the bias field, cooling of the ferrites, and installation of a generous high-voltage gap design. Two quarter-wave resonators combined to form one accelerating unit of about 2.5-m length and 0.6-m diameter should be capable of delivering 120 kV of accelerating voltage in the tuning range 50-60 MHz, up to 200 kV in the range 59-60 MHz. The main advantage of the given resonator design is its full rotational symmetry, which allows calculation and optimization of all electrical properties with maximum reliability.

  7. FCRD Milestone Report: M21AF050901

    SciTech Connect

    Hoelzer, David T; Sokolov, Mikhail A; Byun, Thak Sang; Odette, George R.; Klingensmith, Doug; Gragg, David; Stergar, Eric; Fields, Kirk

    2011-09-01

    The objective of this study was to perform mechanical testing on large scale heats of the advanced ODS 14YWT alloy to investigate the effects of processing parameters on mechanical properties. Mechanical properties tests were conducted on two heats of the advanced ODS 14YWT ferritic alloy: the 14YWT-SM11 was produced by extrusion at ORNL and OW4 was produced by HIP at UCSB. The 14YWT-SM11 showed very high tensile strength compared to OW4, but showed less ductility as a result. The fracture toughness transition temperature of 14YWT-SM11 was determined in two orientations and showed T{sub 0} = 48 C in the favorably strong L-T direction while shifting by 63 C to T{sub 0} = 111 C in the weaker T-L direction. The fracture toughness transition temperature for OW4 was not determined but appeared to be within the range observed for 14YWT-SM11. The fracture toughness of 14YWT-SM11 at room temperature was 86.8 MPa{radical}m and 93.1 MPa{radical}m, which was much higher than that of OW4 (27.4 MPa{radical}m). The strain rate jump tests conducted on OW4 indicated that the creep properties were similar to MA957 at 750 C.

  8. Ferritization treatment of copper in soil by electrokinetic remediation.

    PubMed

    Kimura, Tomoyuki; Takase, Ken-Ichi; Terui, Norifumi; Tanaka, Shunitz

    2007-05-17

    The usefulness of the combined use of the electrokinetic (EK) remediation and a ferrite treatment zone (FTZ) was demonstrated for a treatment of the contaminated soil with heavy metal ions. Copper ions in contaminated soil were transferred into the FTZ by the EK technology and were ferritized in this system. The distribution of copper in a migration chamber after EK treatment with FTZ for 48h showed the large difference in the total and eluted concentration of copper. This indicated that copper ions transferred by EK into the FTZ were ferritized there with ferrite reagent in soil alkalified by EK process. The copper-ferrite compound, which was not dissolved with diluted acid, was retained in the FTZ and accumulated there. The ratio of the ferritized amount of copper against total copper was 92% in the EK process with FTZ after 48 h. PMID:17374444

  9. Low temperature synthesis of zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Bardhan, A.; Ghosh, C. K.; Mitra, M. K.; Das, G. C.; Mukherjee, S.; Chattopadhyay, K. K.

    2010-05-01

    Zinc ferrite (ZnFe 2O 4) nanocrystalline powder materials with various particle sizes were prepared by a unique solid-state combustion method. Phase purity of ZnFe 2O 4 was confirmed by X-ray diffraction studies. High resolution transmission electron microscopic analysis and selected area diffraction pattern also confirmed the correct crystalline phase formation. Particle size was determined from both the transmission electron microscopic images and also from the XRD peak broadening analysis. Oxidation states of different elements present in ZnFe 2O 4 were determined by X-ray photoelectron spectroscopy. Frequency dependent dielectric constant and a.c. conductivity were measured as a function of particle size and both of them were found to decrease with decreasing particle size. These studies indicated that good quality zinc ferrite nanocrystalline powdered materials can be synthesized at low temperature.

  10. Lithium ferrite nanoparticles for ferrofluid applications

    NASA Astrophysics Data System (ADS)

    Sankaranarayanan, V. K.; Prakash, Om; Pant, R. P.; Islam, Mohammad

    2002-11-01

    Nanoparticles of Lithium ferrite in the particle size range of 10 nm have been prepared by a citrate precursor method at a relatively low temperature of 200°C. The particles show characteristic infra red (IR) spectrum of lithium ferrite and broadened X-ray diffraction (XRD) patterns typical of the nanoparticle nature. The sample decomposed at 200°C has the β-LiFe 5O 8 type (a disordered type of spinel) structure which on annealing at 350°C transforms to the α-LiFe 5O 8 type (an ordered type spinel) structure as shown by both IR spectra and XRD studies. Magnetization curves indicate a particle size distribution consisting of both ferromagnetic particles and a superparamagnetic fraction. With 4 ΠMs values of 2000 G these particles could be useful for applications in certain low magnetization ferrofluids.

  11. Cytotoxicity of ferrite particles by MTT and agar diffusion methods for hyperthermic application

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Hyun; Lee, Se-Ho; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Shim, In-Bo; Lee, Yong-Keun

    2005-05-01

    We investigated the cytotoxicity of the prepared various ferrites (Fe-, Li-, Ni/Zn/Cu-, Ba-, Sr-, Co-, Co/Ni-ferrites) using MTT assay as well as agar diffusion method. Their cytotoxicity was compared with that of alginate-encapsulated ferrites. In the MTT assay, Fe 3O 4 and SrFe 12O 19 ferrite showed the highest cell viability of 90%. Alginate-encapsulated Ba-ferrite was ranked mildly cytotoxic, whereas their ferrite particles were ranked cytotoxic.

  12. Cold worked ferritic alloys and components

    DOEpatents

    Korenko, Michael K.

    1984-01-01

    This invention relates to liquid metal fast breeder reactor and steam generator precipitation hardening fully ferritic alloy components which have a microstructure substantially free of the primary precipitation hardening phase while having cells or arrays of dislocations of varying population densities. It also relates to the process by which these components are produced, which entails solution treating the alloy followed by a final cold working step. In this condition, the first significant precipitation hardening of the component occurs during high temperature use.

  13. Atomically flat ultrathin cobalt ferrite islands.

    PubMed

    Martín-García, Laura; Quesada, Adrián; Munuera, Carmen; Fernández, Jose F; García-Hernández, Mar; Foerster, Michael; Aballe, Lucía; de la Figuera, Juan

    2015-10-21

    A route for fabricating structurally perfect cobalt ferrite magnetic nanostructures is demonstrated. Ultrathin islands of up to 100 μm(2) with atomically flat surfaces and free from antiphase boundaries are developed. The extremely low defect concentration leads to a robust magnetic order, even for thicknesses below 1 nm, and exceptionally large magnetic domains. This approach allows the evaluation of the influence of specific extrinsic effects on domain wall pinning. PMID:26306027

  14. Characterizing and Modeling Ferrite-Core Probes

    NASA Astrophysics Data System (ADS)

    Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H.; Aldrin, John C.

    2010-02-01

    In this paper, we accurately and carefully characterize a ferrite-core probe that is widely used for aircraft inspections. The characterization starts with the development of a model that can be executed using the proprietary volume-integral code, VIC-3D©, and then the model is fitted to measured multifrequency impedance data taken with the probe in freespace and over samples of a titanium alloy and aluminum. Excellent results are achieved, and will be discussed.

  15. Compact magnetooptical isolator with cobalt ferrite on silicon photonic circuits

    NASA Astrophysics Data System (ADS)

    Yanaga, Megumi; Shoji, Yuya; Takamura, Yota; Nakagawa, Shigeki; Mizumoto, Tetsuya

    2015-08-01

    In the telecom wavelength range, the magnetooptical effect of cobalt ferrites is approximately 10 times larger than that of conventional magnetooptical materials such as yttrium iron garnets. In this study, we focus on an application of cobalt ferrite to a magnetooptical isolator that is to be miniaturized and made suitable for integration. First, we prepare polycrystalline cobalt ferrite films deposited on a silicon substrate using a MgO buffer layer. Next, we fabricate a waveguide optical isolator of silicon waveguides by the partial deposition of the cobalt ferrite films. An optical isolation ratio of 5.5 dB is demonstrated.

  16. Preparation of single-crystal copper ferrite nanorods and nanodisks

    SciTech Connect

    Du Jimin; Liu Zhimin . E-mail: liuzm@iccas.ac.cn; Wu Weize; Li Zhonghao; Han Buxing . E-mail: hanbx@iccas.ac.cn; Huang Ying

    2005-06-15

    This article, for the first time, reports the preparation of single-crystal copper ferrite nanorods and nanodisks. Using amorphous copper ferrite nanoparticles synthesized by reverse micelle as reaction precursor, single-crystal copper ferrite nanorods were synthesized via hydrothermal method in the presence of surfactant polyethylene glycol (PEG), however, copper ferrite nanodisks were prepared through the same procedures except the surfactant PEG. The resulting nanomaterials have been characterized by powder X-ray diffraction (XRD), selected electron area diffraction (SEAD), and transmission electron microscopy (TEM). The bulk composition of the samples was determined by means of X-ray photoelectron spectroscopy (XPS)

  17. Tunable Dielectric Properties of Ferrite-Dielectric Based Metamaterial

    PubMed Central

    Bi, K.; Huang, K.; Zeng, L. Y.; Zhou, M. H.; Wang, Q. M.; Wang, Y. G.; Lei, M.

    2015-01-01

    A ferrite-dielectric metamaterial composed of dielectric and ferrite cuboids has been investigated by experiments and simulations. By interacting with the electromagnetic wave, the Mie resonance can take place in the dielectric cuboids and the ferromagnetic precession will appear in the ferrite cuboids. The magnetic field distributions show the electric Mie resonance of the dielectric cuboids can be influenced by the ferromagnetic precession of ferrite cuboids when a certain magnetic field is applied. The effective permittivity of the metamaterial can be tuned by modifying the applied magnetic field. A good agreement between experimental and simulated results is demonstrated, which confirms that these metamaterials can be used for tunable microwave devices. PMID:25993433

  18. Tunable dielectric properties of ferrite-dielectric based metamaterial.

    PubMed

    Bi, K; Huang, K; Zeng, L Y; Zhou, M H; Wang, Q M; Wang, Y G; Lei, M

    2015-01-01

    A ferrite-dielectric metamaterial composed of dielectric and ferrite cuboids has been investigated by experiments and simulations. By interacting with the electromagnetic wave, the Mie resonance can take place in the dielectric cuboids and the ferromagnetic precession will appear in the ferrite cuboids. The magnetic field distributions show the electric Mie resonance of the dielectric cuboids can be influenced by the ferromagnetic precession of ferrite cuboids when a certain magnetic field is applied. The effective permittivity of the metamaterial can be tuned by modifying the applied magnetic field. A good agreement between experimental and simulated results is demonstrated, which confirms that these metamaterials can be used for tunable microwave devices. PMID:25993433

  19. Magnetoelastic coupling in epitaxial cobalt ferrite/barium titanate heterostructures

    NASA Astrophysics Data System (ADS)

    Gräfe, Joachim; Welke, Martin; Bern, Francis; Ziese, Michael; Denecke, Reinhard

    2013-08-01

    Ultra-thin cobalt ferrite films have been synthesised on ferroelectric barium titanate crystals. The cobalt ferrite films exhibit a magnetic response to strain induced by structural changes in the barium titanate substrate, suggesting a pathway to multiferroic coupling. These structural changes are achieved by heating through the phase transition temperatures of barium titanate. In addition the ferromagnetic signal of the substrate itself is taken into account, addressing the influence of impurities or defects in the substrate. The cobalt ferrite/barium titanate heterostructure is a suitable oxidic platform for future magnetoelectric applications with an established ferroelectric substrate and widely tuneable magnetic properties by changing the transition metal in the ferrite film.

  20. Properties of ferrites important to their friction and wear behavior

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1983-01-01

    Environmental, chemical and crystallographical effects on the fundamental nature on friction and wear of the ferrites in contact with metals, magnetic tapes and themselves are reviewed. The removal of adsorbed films from the surfaces of ferrites results in very strong interfacial adhesion and high friction in ferrite to metal and ferrite to magnetic tape contacts. The metal ferrite bond at the interface is primarily a chemical bond between the metal atoms and the large oxygen anions in the ferrite surface, and the strength of these bonds is related to the oxygen to metal bond strength in the metal oxide. The more active the metal, the higher is the coefficient of friction. Not only under adhesive conditions, but also under abrasive conditions the friction and wear properties of ferrites are related to the crystallographic orientation. With ferrite to ferrite contact the mating of highest atomic density (most closely packed) direction on matched crystallographic planes, that is, 110 directions on /110/planes, results in the lowest coefficient of friction.

  1. Nanosized copper ferrite materials: Mechanochemical synthesis and characterization

    SciTech Connect

    Manova, Elina; Tsoncheva, Tanya; Paneva, Daniela; Popova, Margarita; Velinov, Nikolay; Kunev, Boris; Tenchev, Krassimir; Mitov, Ivan

    2011-05-15

    Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Moessbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe{sub 2}O{sub 3}. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium. -- Graphical abstract: It is demonstrated that the catalytic behavior of the obtained copper ferrites depends not only on their initial phase composition, but on the concomitant phase transformations by the influence of the reaction medium. Display Omitted Highlights: {yields} Two-step co-precipitation-ball-milling procedure for copper ferrites preparation. {yields} The phase composition of ferrites depends on the milling duration. {yields} Ferrites transforms under the reaction medium, which affects their catalytic behavior. {yields} Ferrites decompose to magnetite and carbides during methanol decomposition. {yields} Agglomeration and further crystallization of ferrite occur during toluene oxidation.

  2. Preferential spin canting in nanosize zinc ferrite

    NASA Astrophysics Data System (ADS)

    Pandey, Brajesh; Litterst, F. J.; Baggio-Saitovitch, E. M.

    2015-07-01

    Zinc ferrite nanoparticles powder with average size of 10.0±0.5 nm was synthesized by the citrate precursor route. We studied the structural and magnetic properties using X-ray diffraction, vibrating sample magnetometry and Mössbauer spectroscopy. X-ray diffraction patterns show that the synthesized zinc ferrite possesses good spinel structure. Both Mössbauer and magnetization data indicate superparamagnetic ferrimagnetic particles at room temperature. The magnetic behavior is determined by a considerable degree of cation inversion with FeIII in tetrahedral A-sites. Mössbauer spectroscopy at low temperature and in high applied magnetic field reveals that A-site spins are aligned antiparallel to the applied field with some possible angular scatter whereas practically all octahedral B-site spins are canted contrasting some earlier reported partial B-site spin canting in nanosize zinc ferrite. Deviations from the antiferromagnetic arrangement of B-site spins are supposed to be caused by magnetic frustration effects.

  3. Ferrite nanoparticles for future heart diagnostics

    NASA Astrophysics Data System (ADS)

    Hong, Nguyen Hoa; Raghavender, A. T.; Ciftja, O.; Phan, M.-H.; Stojak, K.; Srikanth, H.; Zhang, Yin Hua

    2013-08-01

    Normally, CoFe2O4 has been known as ferromagnetic ferrite with a quite large magnetic moment. However, since we aim to inject the particles into the human body, we are also interested in ZnFe2O4 because in the human body, Fe and Zn exist, so that adding ZnFe2O4 is safer. In both cases, the nanoparticles are coated by silica in order to get rid of toxicity. Our main purpose is to test whether these nanoparticles affect the contractile function of heart cells. Our results on rat's heart cells have shown that both Zn and Co ferrites improved the contractility of heart cells. Notably, although both nanoparticles increased contraction and delayed relaxation, Co ferrites induced a greater contraction but with a slower relaxation. We can theoretically argue that the magnetization effects of the quantum dots have a considerable effect on the pulsating properties of the heart cells. Through this effect, the locally applied magnetic field is able to induce as well as turn on/off various regular beating patterns, thus, resetting the heart beatings.

  4. Studies on the activation energy from the ac conductivity measurements of rubber ferrite composites containing manganese zinc ferrite

    NASA Astrophysics Data System (ADS)

    Hashim, Mohd.; Alimuddin; Kumar, Shalendra; Shirsath, Sagar E.; Mohammed, E. M.; Chung, Hanshik; Kumar, Ravi

    2012-11-01

    Manganese zinc ferrites (MZF) have resistivities between 0.01 and 10 Ω m. Making composite materials of ferrites with either natural rubber or plastics will modify the electrical properties of ferrites. The moldability and flexibility of these composites find wide use in industrial and other scientific applications. Mixed ferrites belonging to the series Mn(1-x)ZnxFe2O4 were synthesized for different ‘x’ values in steps of 0.2, and incorporated in natural rubber matrix (RFC). From the dielectric measurements of the ceramic manganese zinc ferrite and rubber ferrite composites, ac conductivity and activation energy were evaluated. A program was developed with the aid of the LabVIEW package to automate the measurements. The ac conductivity of RFC was then correlated with that of the magnetic filler and matrix by a mixture equation which helps to tailor properties of these composites.

  5. Ferritic steel melt and FLiBe/steel experiment : melting ferritic steel.

    SciTech Connect

    Troncosa, Kenneth P.; Smith, Brandon M.; Tanaka, Tina Joan

    2004-11-01

    In preparation for developing a Z-pinch IFE power plant, the interaction of ferritic steel with the coolant, FLiBe, must be explored. Sandia National Laboratories Fusion Technology Department was asked to drop molten ferritic steel and FLiBe in a vacuum system and determine the gas byproducts and ability to recycle the steel. We tried various methods of resistive heating of ferritic steel using available power supplies and easily obtained heaters. Although we could melt the steel, we could not cause a drop to fall. This report describes the various experiments that were performed and includes some suggestions and materials needed to be successful. Although the steel was easily melted, it was not possible to drip the molten steel into a FLiBe pool Levitation melting of the drop is likely to be more successful.

  6. An Implicit LU/AF FDTD Method

    NASA Technical Reports Server (NTRS)

    Beggs, John H.; Briley, W. Roger

    2001-01-01

    There has been some recent work to develop two and three-dimensional alternating direction implicit (ADI) FDTD schemes. These ADI schemes are based upon the original ADI concept developed by Peaceman and Rachford and Douglas and Gunn, which is a popular solution method in Computational Fluid Dynamics (CFD). These ADI schemes work well and they require solution of a tridiagonal system of equations. A new approach proposed in this paper applies a LU/AF approximate factorization technique from CFD to Maxwell s equations in flux conservative form for one space dimension. The result is a scheme that will retain its unconditional stability in three space dimensions, but does not require the solution of tridiagonal systems. The theory for this new algorithm is outlined in a one-dimensional context for clarity. An extension to two and threedimensional cases is discussed. Results of Fourier analysis are discussed for both stability and dispersion/damping properties of the algorithm. Results are presented for a one-dimensional model problem, and the explicit FDTD algorithm is chosen as a convenient reference for comparison.

  7. Prevention of Obesity and Insulin Resistance by Estrogens Requires ERα Activation Function-2 (ERαAF-2), Whereas ERαAF-1 Is Dispensable

    PubMed Central

    Handgraaf, Sandra; Riant, Elodie; Fabre, Aurélie; Waget, Aurélie; Burcelin, Rémy; Lière, Philippe; Krust, Andrée; Chambon, Pierre; Arnal, Jean-François; Gourdy, Pierre

    2013-01-01

    The beneficial metabolic actions of estrogen-based therapies are mainly mediated by estrogen receptor α (ERα), a nuclear receptor that regulates gene transcription through two activation functions (AFs): AF-1 and AF-2. Using mouse models deleted electively for ERαAF-1 (ERαAF-1°) or ERαAF-2 (ERαAF-2°), we determined their respective roles in the actions of estrogens on body composition and glucose homeostasis in response to either a normal diet or a high-fat diet (HFD). ERαAF-2° males and females developed accelerated weight gain, massive adiposity, severe insulin resistance, and glucose intolerance—quite reminiscent of the phenotype observed in mice deleted for the entire ERα protein (ERα−/−). In striking contrast, ERαAF-1° and wild-type (wt) mice shared a similar metabolic phenotype. Accordingly, 17β-estradiol administration regulated key metabolic genes in insulin-sensitive tissues and conferred a strong protection against HFD-induced metabolic disturbances in wt and ERαAF-1° ovariectomized mice, whereas these actions were totally abrogated in ERαAF-2° and ERα−/− mice. Thus, whereas both AFs have been previously shown to contribute to endometrial and breast cancer cell proliferation, the protective effect of estrogens against obesity and insulin resistance depends on ERαAF-2 but not ERαAF-1, thereby delineating new options for selective modulation of ERα. PMID:23903353

  8. Tuning the Music: Acoustic Force Spectroscopy (AFS) 2.0.

    PubMed

    Kamsma, Douwe; Creyghton, Ramon; Sitters, Gerrit; Wuite, Gijs J L; Peterman, Erwin J G

    2016-08-01

    AFS is a recently introduced high-throughput single-molecule technique that allows studying structural and mechanochemical properties of many biomolecules in parallel. To further improve the method, we developed a modelling tool to optimize the layer thicknesses, and a calibration method to experimentally validate the modelled force profiles. After optimization, we are able to apply 350pN on 4.5μm polystyrene beads, without the use of an amplifier, at the coverslip side of the AFS chip. Furthermore, we present the use of a transparent piezo to generate the acoustic force and we show that AFS can be combined with high-NA oil or water-immersion objectives. With this set of developments AFS will be applicable to a broad range of single-molecule experiments. PMID:27163865

  9. Ferritic weldment of grain-refined ferritic steels for cryogenic use

    SciTech Connect

    Kim, H.J.; Syn, C.K.; Morris, J.W. Jr.

    1981-08-01

    The problem of welding grain-refined Fe-12Ni-0.25Ti for 4K service was first approached in this laboratory by using high nickel filler metals such as are often specified for ferritic steel weldments at 77K. This approach led to an undesirable brittleness in the fusion zone and a low yield strength in the weld metal. A more promising approach was developed in joint research between the Japanese steel companies, who showed that quench-and-tempered 9Ni steel may be welded for 77K service with a matching ferritic filler if a multipass GTAW technique is employed. The present paper reports the initial resultsof similar studies on ferritic GTA weldments in grain-refined 9Ni steel. Information is included on the preparation of the 9Ni steel and the weld filler metal, on the welding procedure, the microstructure of both the weld metal and the heat affected zone, and on impact toughness and fracture toughness testing at 77/sup 0/K and 4.2/sup 0/K. The results show that it is possible to weld grain-refined 9Ni steel with ferritic weld filler metal so as to retain good toughness at cryogenic temperatures. The results of this work may permit the utilization of retreated commercial grade 9Ni steel in structural applications within helium-cooled cryogenic devices where high strength and good toughness are required. (LCL)

  10. Irradiation embrittlement of neutron-irradiated low activation ferritic steels

    NASA Astrophysics Data System (ADS)

    Kayano, H.; Kimura, A.; Narui, M.; Sasaki, Y.; Suzuki, Y.; Ohta, S.

    1988-07-01

    Effects of neutron irradiation and additions of small amounts of alloying elements on the ductile-brittle transition temperature (DBTT) of three different groups of ferritic steels were investigated by means of the Charpy impact test in order to gain an insight into the development of low-activation ferritic steels suitable for the nuclear fusion reactor. The groups of ferritic steels used in this study were (1) basic 0-5% Cr ferritic steels, (2) low-activation ferritic steels which are FeCrW steels with additions of small amounts of V, Mn, Ta, Ti, Zr, etc. and (3) FeCrMo, Nb or V ferritic steels for comparison. In Fe-0-15% Cr and FeCrMo steels, Fe-3-9% Cr steels showed minimum brittleness and provided good resistance against irradiation embrittlement. Investigations on the effects of additions of trace amounts of alloying elements on the fracture toughness of low-activation ferritic steels made clear the optimum amounts of each alloying element to obtain higher toughness and revealed that the 9Cr-2W-Ta-Ti-B ferritic steel showed the highest toughness. This may result from the refinement of crystal grains and improvement of quenching characteristics caused by the complex effect of Ti and B.

  11. Intragranular ferrite nucleation in medium-carbon vanadium steels

    SciTech Connect

    Ishikawa, Fusao; Takahashi, Toshihiko ); Ochi, Tatsurou . Muroran R D Lab.)

    1994-05-01

    In this study, the mechanism of intragranular ferrite nucleation is investigated. It is found that intragranular ferrite idiomorphs'' nucleate at vanadium nitrides which precipitate at manganese sulfide particles during cooling in the austenite region. It is observed that intragranular ferrite has the Baker-Nutting orientation relationship with vanadium nitride which precipitated at manganese sulfide. According to classical nucleation theory, the proeutectoid ferrite nucleation rate depends on the following factors: (1) the driving free energy for ferrite nucleation, (2) the diffusivity of carbon atoms in austenite, and (3) the increase in the interfacial energy associated with ferrite nucleation. In the Baker-Nutting orientation relationship, the lattice mismatch across the habit planes is likely to be very small. Depleted zones of solute atoms such as vanadium are assumed to be formed in the austenite matrix around precipitates. The effect of the depleted zones on factors (1) and (2) is estimated thermodynamically and it is proved that those effects are negligibly small. Thus, the authors conclude that the most important factor in nucleation kinetics of intragranular ferrite is the formation of precipitates which can develop coherent, low energy interfaces with ferrite.

  12. Synthesis And Characterization Of Reduced Size Ferrite Reinforced Polymer Composites

    SciTech Connect

    Borah, Subasit; Bhattacharyya, Nidhi S.

    2008-04-24

    Small sized Co{sub 1-x}Ni{sub x}Fe{sub 2}O{sub 4} ferrite particles are synthesized by chemical route. The precursor materials are annealed at 400, 600 and 800 C. The crystallographic structure and phases of the samples are characterized by X-ray diffraction (XRD). The annealed ferrite samples crystallized into cubic spinel structure. Transmission Electron Microscopy (TEM) micrographs show that the average particle size of the samples are <20 nm. Particulate magneto-polymer composite materials are fabricated by reinforcing low density polyethylene (LDPE) matrix with the ferrite samples. The B-H loop study conducted at 10 kHz on the toroid shaped composite samples shows reduction in magnetic losses with decrease in size of the filler sample. Magnetic losses are detrimental for applications of ferrite at high powers. The reduction in magnetic loss shows a possible application of Co-Ni ferrites at high microwave power levels.

  13. Ferrites and Different Winding Types in Permanent Magnet Synchronous Motor

    NASA Astrophysics Data System (ADS)

    Sekerák, Peter; Hrabovcová, Valéria; Pyrhönen, Juha; Kalamen, Lukáš; Rafajdus, Pavol; Onufer, Matúš

    2012-05-01

    This paper deals with design of permanent magnet synchronous machines with ferrites. The ferrites became popular due to their low cost and cost increasing of NdFeB. The progress in ferrite properties in the last decade allows the use of ferrites in high power applications. Three models of ferrite motors are presented. It is shown that also the type of stator winding and the shape of the slot opening have an important effect on the PMSM properties. The first motor has a distributed winding, the second motor has concentrated, non-overlapping winding and open stator slots. The third motor has a concentrated non-overlapping winding and semi - open slots. All models are designed for the same output power and they do not have the same dimensions. The paper shows how important the design of an electric machine is for excellent motor properties or better to say how the motor properties can be improved by an appropriate design.

  14. Electrical transport behavior of nonstoichiometric magnesium-zinc ferrite

    SciTech Connect

    Ghatak, S.; Sinha, M.; Meikap, A.K.; Pradhan, S.K.

    2010-08-15

    This paper presents the direct current conductivity, alternate current conductivity and dielectric properties of nonstoichiometric magnesium-zinc ferrite below room temperature. The frequency exponent (s) of conductivity shows an anomalous temperature dependency. The magnitude of the temperature exponent (n) of dielectric permittivity strongly depends on frequency and its value decreases with increasing frequency. The grain boundary contribution is dominating over the grain contribution in conduction process and the temperature dependence of resistance due to grain and grain boundary contribution exhibits two activation regions. The ferrite shows positive alternating current magnetoconductivity. The solid state processing technique was used for the preparation of nanocrystalline ferrite powder from oxides of magnesium, zinc and iron. The X-ray diffraction methods were used in determining the structure and composition of obtained ferrite, while multimeter, impedance analyzer, liquid nitrogen cryostat and electromagnet were used in the study of conducting and dielectric properties of ferrite.

  15. Cobalt ferrite nanoparticles under high pressure

    SciTech Connect

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V.; Errandonea, D.

    2015-08-21

    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  16. Helium entrapment in a nanostructured ferritic alloy

    SciTech Connect

    Edmondson, Philip D; Parish, Chad M; Zhang, Yanwen; Hallen, Dr Anders; Miller, Michael K

    2011-01-01

    The nanostructured ferritic alloy 14YWT has been irradiated with He ions to simulate accumulation of He during the service life of a nuclear reactor to test the hypothesis that the large surface area for nanoclusters is a preferential nucleation site for bubbles. Transmission electron microscopy and atom probe tomography showed that high number densities of He bubbles were formed on the surface of nanoclusters and Ti(C,N) precipitates, and along grain boundaries and dislocations. At higher fluences, facetted bubbles are formed and it is postulated that the lowest energy state configuration is the truncated rhombic dodecahedron.

  17. Corrosion behavior of magnetic ferrite coating prepared by plasma spraying

    SciTech Connect

    Liu, Yi; Wei, Shicheng Tong, Hui; Tian, Haoliang; Liu, Ming; Xu, Binshi

    2014-12-15

    Graphical abstract: The saturation magnetization (M{sub s}) of the ferrite coating is 34.417 emu/g while the M{sub s} value of the ferrite powder is 71.916 emu/g. It can be seen that plasma spray process causes deterioration of the room temperature soft magnetic properties. - Highlights: • Spinel ferrite coatings have been prepared by plasma spraying. • The coating consists of nanocrystalline grains. • The saturation magnetization of the ferrite coating is 34.417 emu/g. • Corrosion behavior of the ferrite coating was examined in NaCl solution. - Abstract: In this study, spray dried spinel ferrite powders were deposited on the surface of mild steel substrate through plasma spraying. The structure and morphological studies on the ferrite coatings were carried out using X-ray diffraction, scanning electron microscope and Raman spectroscopy. It was showed that spray dried process was an effective method to prepare thermal spraying powders. The coating showed spinel structure with a second phase of LaFeO{sub 3}. The magnetic property of the ferrite samples were measured by vibrating sample magnetometer. The saturation magnetization (M{sub s}) of the ferrite coating was 34.417 emu/g. The corrosion behavior of coating samples was examined by electrochemical impedance spectroscopy. EIS diagrams showed three corrosion processes as the coating immersed in 3.5 wt.% NaCl solution. The results suggested that plasma spraying was a promising technology for the production of magnetic ferrite coatings.

  18. Soft ferrite cores characterization for integrated micro-inductors

    NASA Astrophysics Data System (ADS)

    Nguyen, Yen Mai; Bourrier, David; Charlot, Samuel; Valdez-Nava, Zarel; Bley, Vincent; Combettes, Céline; Lopez, Thomas; Laur, Jean-Pierre; Brunet, Magali

    2014-10-01

    Low-profile soft ferrite films constitute a competitive solution for the integration of micro-inductors on silicon in low-power medium frequency dc-dc conversion applications. The high resistivity of soft ferrites is indeed a major advantage for operating frequencies in the range of 5‒10 MHz. We have studied several soft ferrites, including commercial ferrite films and ferrites made in-house. Test inductors were fabricated at a wafer level using micro-machining and assembling techniques. The proposed process is based on a sintered ferrite core placed between thick electroplated copper windings. The low-profile ferrite cores of 1.2  ×  2.6  ×  0.1 mm3 were produced by two methods using green tape-cast films or ferrite powders. This article presents the magnetic characterization of the fabricated ferrite cores, cut and printed in a rectangular shape and sintered at different temperatures. Comparisons are made in order to find the best material for the core that can offer micro-inductors a high inductance in the range of 200-1000 nH at 6 MHz, and that generate the smallest losses. Thanks to a test inductor, it is demonstrated that with a commercial ferrite core, an inductance density of 215 nH mm-2 up to 6 MHz could be reached. Extracted losses at 6 MHz, under 10 mT are in the range of 0.7 to 2.5 W cm-3.

  19. Anomalous magnetic behaviour of zinc and chromium ferrites without any hyperfine splitting

    NASA Astrophysics Data System (ADS)

    Pandey, B.; Verma, H. C.

    2008-04-01

    Two groups of ferrite namely zinc ferrite and chromium ferrite were synthesized by citrate precursor route in the size range of 8 to 35 nm. We have studied the structural and magnetic behaviour of these ferrites using X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Mössbauer spectroscopic techniques. Our studies show that the nanocrystalline ferrites interact with the hand magnet strongly and give large magnetization in the VSM measurement. The maximum magnetization in the samples sensitively depends on the particle size of synthesized ferrites. We observed as large as 28 Am2/kg of magnetization in the zinc ferrite nanoparticles while that in chromium ferrite is around 11 Am2/kg. In spite of the large magnetization in the zinc ferrite nanoparticles we did not observe any hyperfine splitting even down to 12 K of temperature. Similar behaviour is also observed for chromium ferrite down to 16 K.

  20. A 30-GHz Hexagonal Ferrite Phase Shifter

    NASA Astrophysics Data System (ADS)

    Semenov, A. S.; Slavin, A. N.; Mantese, J. V.

    2005-03-01

    Highly-anisotropic hexaferrites, such as barium ferrite BaFe12O19 (BFO), are ideal for millimeter wave phase shifters due to a large ferromagnetic resonance frequency at low magnetic bias field H. It enables one to make millimeter-wave devices with compact magnetic systems. Here we discuss the design, fabrication and characterization of a BFO phase shifter. A microstrip line deposited on a ferrite substrate supports the propagation of electromagnetic wave, leading to a phase shift kb, where k is the wave number and b is the length of the microstrip line. As k is a function of the bias H, we obtain a differential phase shift with a change of H. A phase shifter consisting of a single crystal (7 x 7 x 0.5 mm^3) BFO and a 500 μm wide stripline was evaluated at 30 GHz. A differential phase shift of 30 deg. was measured for H=1.2 kOe. The measured value of the insertion loss was about 10 dB. -Work supported by a grant from the Delphi Automotive Corporation.

  1. Phase transformation of strontium hexagonal ferrite

    NASA Astrophysics Data System (ADS)

    Bilovol, V.; Martínez-García, R.

    2015-11-01

    The phase transformation of strontium hexagonal ferrite (SrFe12O19) to magnetite (Fe3O4) as main phase and strontium carbonate (SrCO3) as secondary phase is reported here. SrFe12O19 powder was obtained by a heat treatment at 250 °C under controlled oxygen flow. It was observed that the phase transformation occurred when the SrFe12O19 ferrite was heated up to 625 °C in confinement conditions. This transformation took place by a combination of three factors: the presence of stresses in the crystal lattice of SrFe12O19 due to a low synthesis temperature, the reduction of Fe3+ to Fe2+ during the heating up to 625 °C, and the similarity of the coordination spheres of the iron atoms present in the S-block of SrFe12O19 and Fe3O4. X-ray diffraction analysis confirmed the existence of strain and crystal deformation in SrFe12O19 and the absence of them in the material after the phase transformation. Dispersive X-ray absorption spectroscopy and Fe57 Mössbauer spectroscopy provided evidences of the reduction of Fe3+ to Fe2+ in the SrFe12O19 crystal.

  2. Cast Stainless Steel Ferrite and Grain Structure

    SciTech Connect

    Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

  3. Effects of Iron Depletion on CALM-AF10 Leukemias

    PubMed Central

    Heath, Jessica L.; Weiss, Joshua M.

    2014-01-01

    Iron, an essential nutrient for cellular growth and proliferation, enters cells via clathrin-mediated endocytosis (CME). The clathrin assembly lymphoid myeloid (CALM) protein plays an essential role in the cellular import of iron by CME. CALM-AF10 leukemias harbor a single copy of the normal CALM gene, and may therefore be more sensitive to the growth inhibitory effect of iron restriction compared with normal hematopoietic cells. We found that Calm heterozygous (CalmHET) murine fibroblasts exhibit signs of iron deficiency, with increased surface transferrin receptor (sTfR) levels and reduced growth rates. CalmHET hematopoietic cells are more sensitive in vitro to iron chelators than their wild type counterparts. Iron chelation also displayed toxicity towards cultured CalmHET CALM-AF10 leukemia cells and this effect was additive to that of chemotherapy. In mice transplanted with CalmHET CALM-AF10 leukemia, we found that dietary iron restriction reduces tumor burden in the spleen. However, dietary iron restriction, used alone or in conjunction with chemotherapy, did not increase survival of mice with CalmHET CALM-AF10 leukemia. In summary, while Calm heterozygosity results in iron deficiency and increased sensitivity to iron chelation in vitro, our data in mice do not suggest that iron depletion strategies would be beneficial for the therapy of CALM-AF10 leukemia patients. PMID:25193880

  4. Simulations of ferrite-dielectric-wire composite negative index materials.

    PubMed

    Rachford, Frederic J; Armstead, Douglas N; Harris, Vincent G; Vittoria, Carmine

    2007-08-01

    We perform extensive finite difference time domain simulations of ferrite based negative index of refraction composites. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the ferrite resonance. Notwithstanding the extreme anisotropy in the index of refraction of the composite, negative refraction is seen at the composite air interface allowing the construction of a focusing concave lens with a magnetically tunable focal length. PMID:17930783

  5. Nickel hydroxide/cobalt-ferrite magnetic nanocatalyst for alcohol oxidation.

    PubMed

    Bhat, Pooja B; Inam, Fawad; Bhat, Badekai Ramachandra

    2014-08-11

    A magnetically separable, active nickel hydroxide (Brønsted base) coated nanocobalt ferrite catalyst has been developed for oxidation of alcohols. High surface area was achieved by tuning the particle size with surfactant. The surface area of 120.94 m2 g(-1) has been achieved for the coated nanocobalt ferrite. Improved catalytic activity and selectivity were obtained by synergistic effect of transition metal hydroxide (basic hydroxide) on nanocobalt ferrite. The nanocatalyst oxidizes primary and secondary alcohols efficiently (87%) to corresponding carbonyls in good yields. PMID:25075969

  6. Magnetooptical and crystalline properties of sputtered garnet ferrite film on spinel ferrite buffer layer

    NASA Astrophysics Data System (ADS)

    Furuya, Akinori; Sasaki, Ai-ichiro; Morimura, Hiroki; Kagami, Osamu; Tanabe, Takaya

    2016-09-01

    The purpose of this study is to provide garnet films for volumetric magnetic holography. Volumetric magnetic holography usually employs an easily obtainable short-wavelength laser (visible light, not infrared light) with a large diffraction intensity. Bi-substituted garnet ferrite with a large Faraday rotation is promising for volumetric magnetic holography applications in the visible light region. However, a garnet film without a deteriorated layer must be obtained because a deteriorated layer (minute polycrystalline grains containing an amorphous phase) is formed during the initial deposition on a glass substrate. In particular, the required magnetooptical properties have not been obtained in a thin garnet film (100 nm or less) after annealing (1 h, 700 °C, oxygen atmosphere). Therefore, there is a need for excellent garnet films with the required magnetooptical (MO) properties even if the films are thin. By using a spinel ferrite buffer layer for garnet film deposition, we could obtain a thin garnet film with excellent MO properties. We determined the effect of the initial buffer layer on the crystallinity of the deposited garnet films by observing the film cross section. In addition, we undertook a qualitative estimation of the influence of the crystallinity and optical properties of the garnet film on a glass substrate with a spinel ferrite buffer layer.

  7. AF-GEOSpace Version 2.5: Space Environment Software

    NASA Astrophysics Data System (ADS)

    Hilmer, R. V.; Hall, T.; Roth, C.; Ling, A.; Ginet, G. P.; Madden, D.

    2010-12-01

    AF-GEOSpace is a graphics-intensive software program with space environment models and applications developed by the Space Weather Center of Excellence at AFRL. The software addresses a wide range of physical domains, e.g., solar disturbance propagation, geomagnetic field and radiation belt configurations, auroral particle precipitation, and ionospheric scintillation. AF-GEOSpace has become a platform for developing and prototyping space weather visualization products. The new AF-GEOSpace Version 2.5 (release scheduled for 2010) expands on the content of Version 2.1 by including modules addressing the following new topics: (1) energetic proton maps for the South Atlantic Anomaly (from Ginet et al. [2007]), (2) GPS scintillation outage simulation tools, (3) magnetopause location determination (Shue et al. [1998]), (4) a plasmasphere model (Global Core Plasma Model, 2009 version based on Gallagher et al. [2000]), (5) a standard ionospheric model (International Reference Ionosphere 2007), (6) the CAMMICE/MICS model of inner magnetosphere plasma population (based on Roeder et al. [2005]), (7) magnetic field models (e.g., Tsyganenko and Sitnov [2005]), and (8) loading and displaying externally-produced 3D gridded data sets within AF-GEOSpace. Improvements to existing Version 2.1 capabilities include: (1) a 2005 update to the geomagnetic cutoff rigidity model of Smart and Shea [2003], (2) a 2005 update to the ionospheric scintillation Wide-Band Model (WBMOD) of Secan and Bussey [1994], and (3) improved magnetic field flux mapping options for the existing set of AF-GEOSpace radiation belt models. A basic review of these new AF-GEOSpace capabilities will be provided. To obtain a copy of the software, please contact the first author.

  8. AF-GEOSpace Version 2.1 Release

    NASA Astrophysics Data System (ADS)

    Hilmer, R. V.; Ginet, G. P.; Hall, T.; Holeman, E.; Madden, D.; Perry, K. L.; Tautz, M.; Roth, C.

    2006-05-01

    AF-GEOSpace Version 2.1 is a graphics-intensive software program with space environment models and applications developed recently by the Space Weather Center of Excellence at AFRL. A review of new and planned AF-GEOSpace capabilities will be given. The software addresses a wide range of physical domains and addresses such topics as solar disturbance propagation, geomagnetic field and radiation belt configurations, auroral particle precipitation, and ionospheric scintillation. Building on the success of previous releases, AF-GEOSpace has become a platform for the rapid prototyping of automated operational and simulation space weather visualization products and helps with a variety of tasks, including: orbit specification for radiation hazard avoidance; satellite design assessment and post-event anomaly analysis; solar disturbance effects forecasting; determination of link outage regions for active ionospheric conditions; satellite magnetic conjugate studies, scientific model validation and comparison, physics research, and education. Previously, Version 2.0 provided a simplified graphical user interface, improved science and application modules, significantly enhanced graphical performance, common input data archive sets, and 1-D, 2-D, and 3- D visualization tools for all models. Dynamic capabilities permit multiple environments to be generated at user- specified time intervals while animation tools enable the display of satellite orbits and environment data together as a function of time. Building on the Version 2.0 software architecture, AF-GEOSpace Version 2.1 includes a host of new modules providing, for example, plasma sheet charged particle fluxes, neutral atmosphere densities, 3-D cosmic ray cutoff maps, low-altitude trapped proton belt flux specification, DMSP particle data displays, satellite magnetic field footprint mapping determination, and meteor sky maps and shower/storm fluxes with spacecraft impact probabilities. AF-GEOSpace Version 2.1 was

  9. GPIM AF-M315E Propulsion System

    NASA Technical Reports Server (NTRS)

    Spores, Ronald A.; Masse, Robert; Kimbrel, Scott; McLean, Chris

    2014-01-01

    The NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) Technology Demonstration Mission (TDM) will demonstrate an operational AF-M315E green propellant propulsion system. Aerojet-Rocketdyne is responsible for the development of the propulsion system payload. This paper statuses the propulsion system module development, including thruster design and system design; Initial test results for the 1N engineering model thruster are presented. The culmination of this program will be high-performance, green AF-M315E propulsion system technology at TRL 7+, with components demonstrated to TRL 9, ready for direct infusion to a wide range of applications for the space user community.

  10. Characterization of Irradiated Nanostructured Ferritic Steels

    SciTech Connect

    Bentley, James; Hoelzer, David T; Tanigawa, H.; Yamamoto, T.; Odette, George R.

    2007-01-01

    The past decade has seen the development of a new class of mechanically alloyed (MA) ferritic steels with outstanding mechanical properties that come, at least in part, from the presence of high concentrations (>10{sup 23} m{sup -3}) of Ti-, Y-, and O-enriched nanoclusters (NC). From the outset, there has been much interest in their potential use for applications to fission and proposed fusion reactors, not only because of their attractive high-temperature strength, but also because the presence of NC may result in a highly radiation-resistant material by efficiently trapping point defects to enhance recombination. Of special interest for fusion applications is the potential of NC to trap transmutation-produced He in high concentrations of small cavities, rather than in fewer but larger cavities that lead to greater radiation-induced swelling and other degraded properties.

  11. Joining Techniques for Ferritic ODS Alloys

    SciTech Connect

    V.G. Krishnardula; V.G. Krishnardula; D.E. Clark; T.C. Totemeier

    2005-06-01

    This report presents results of research on advanced joining techniques for ferritic oxide-dispersion strengthened alloys MA956 and PM2000. The joining techniques studied were resistance pressure welding (also known as pressure forge welding), transient liquid phase bonding, and diffusion bonding. All techniques were shown to produce sound joints in fine-grained, unrecrystallized alloys. Post-bond heat treatment to produce a coarse-grained, recrystallized microstructure resulted in grain growth across the bondline for transient liquid phase and diffusion bonds, giving microstructures essentially identical to that of the parent alloy in the recrystallized condition. The effects of bond orientation, boron interlayer thickness, and bonding parameters are discussed for transient liquid phase and diffusion bonding. The report concludes with a brief discussion of ODS joining techniques and their applicability to GEN IV reactor systems.

  12. Ethanol sensor based on nanocrystallite cadmium ferrite

    SciTech Connect

    Gadkari, Ashok B.; Shinde, Tukaram J.; Vasambekar, Pramod N.

    2015-06-24

    The cadmium ferrite was synthesized by oxalate co-precipitation method. The crystal structure and surface morphology were examined by X-ray diffraction and SEM techniques, respectively. The nanocrystallite CdFe{sub 2}O{sub 4} sensor was tested for LPG, Cl{sub 2} and C{sub 2}H{sub 5}OH. The sensitivity was measured at various operating temperatures in the range of 100-400°C. The sensor shows highest sensitivity and selectivity to C{sub 2}H{sub 5}OH at 350°C. The response and recovery time was measured at operating temperature of 350°C. The sensor exhibits a lower response and recovery time for LPG and Cl{sub 2} as compared to ethanol.

  13. High strength ferritic alloy-D53

    DOEpatents

    Hagel, William C.; Smidt, Frederick A.; Korenko, Michael K.

    1977-01-01

    A high strength ferritic alloy is described having from about 0.2% to about 0.8% by weight nickel, from about 2.5% to about 3.6% by weight chromium, from about 2.5% to about 3.5% by weight molybdenum, from about 0.1% to about 0.5% by weight vanadium, from about 0.1% to about 0.5% by weight silicon, from about 0.1% to about 0.6% by weight manganese, from about 0.12% to about 0.20% by weight carbon, from about 0.02% to about 0.1% by weight boron, a maximum of about 0.05% by weight nitrogen, a maximum of about 0.02% by weight phosphorous, a maximum of about 0.02% by weight sulfur, and the balance iron.

  14. Design of tough ferritic steels for cryogenic use

    SciTech Connect

    Morris, J.W. Jr.

    1985-10-01

    This paper describes the design of ferritic steels and weldments that combine strength and toughness at cryogenic temperatures. The alloy must have a ductile-brittle transition temperature below the intended service temperature and a high fracture toughness in the ductile mode. Its systematic design uses the microstructure-property relations that govern the transition temperature and fracture toughness to identify a suitable microstructure, and then employs the microstructure-processing relations that govern its thermal response to manipulate the microstructure into the appropriate form. The procedure is illustrated by describing the heat treatments, microstructures and properties of a variety of laboratory and commercial alloys, including conventional ''9Ni'' steel, the low-Ni and Fe-Mn ferritic steels that have been developed as an alternative to 9Ni, the 12Ni steels that are promising for use at 4K, and the welding procedures and ferritic filler metals that are useful for ferritic cryogenic steels.

  15. Ferrite core coupled slapper detonator apparatus and method

    DOEpatents

    Boberg, Ralph E.; Lee, Ronald S.; Weingart, Richard C.

    1989-01-01

    Method and apparatus are provided for coupling a temporally short electric power pulse from a thick flat-conductor power cable into a thin flat-conductor slapper detonator circuit. A first planar and generally circular loop is formed from an end portion of the power cable. A second planar and generally circular loop, of similar diameter, is formed from all or part of the slapper detonator circuit. The two loops are placed together, within a ferrite housing that provides a ferrite path that magnetically couples the two loops. Slapper detonator parts may be incorporated within the ferrite housing. The ferrite housing may be made vacuum and water-tight, with the addition of a hermetic ceramic seal, and provided with an enclosure for protecting the power cable and parts related thereto.

  16. Dynamic recrystallization of ferrite in interstitial free steel

    SciTech Connect

    Tsuji, N.; Matsubara, Y.; Saito, Y.

    1997-08-15

    The present study using IF steel confirmed that dynamic recrystallization can occur also in ferrite where it has been generally considered that recovery is an only restoration process during hot deformation. Although the occurrence of DRX has been clarified by microstructural observations and crystallographic determinations, stress-strain curves do not show obvious drop of stress which has been typically reported in the case of DRX of austenite. This result indicates that it is quite difficult to distinguish whether DRX occurs in ferrite only by stress-strain behavior. The noticeable feature of DRX of ferrite is inhomogeneity of recrystallization, i.e., some of the initial grains are hard to recrystallize. This is presumably due to orientation dependence of recrystallization, which is the essential feature of ferrite.

  17. New sintering process adjusts magnetic value of ferrite cores

    NASA Technical Reports Server (NTRS)

    Vinal, A. W.

    1964-01-01

    A two-phase sintering technique based on time and temperature permits reversible control of the coercive threshold of sintered ferrite cores. Threshold coercivity may be controlled over a substantial range of values by selective control of the cooling rate.

  18. Dielectric investigations of polycrystalline samarium bismuth ferrite ceramic

    SciTech Connect

    Palaimiene, E.; Macutkevic, J.; Banys, J.; Karpinsky, D. V.; Kholkin, A. L.

    2015-01-05

    Results of broadband dielectric investigations of samarium doped bismuth ferrite ceramics are presented in wide temperature range (20–800 K). At temperatures higher than 400 K, the dielectric properties of samarium bismuth ferrite ceramics are governed by Maxwell-Wagner relaxation and electrical conductivity. The DC conductivity increases and activation energy decreases with samarium concentration. In samarium doped bismuth ferrite, the ferroelectric phase transition temperature decreases with samarium concentration and finally no ferroelectric order is observed at x = 0.2. At lower temperatures, the dielectric properties of ferroelectric samarium doped bismuth ferrite are governed by ferroelectric domains dynamics. Ceramics with x = 0.2 exhibit the relaxor-like behaviour.

  19. Ferrite core coupled slapper detonator apparatus and method

    DOEpatents

    Boberg, R.E.; Lee, R.S.; Weingart, R.C.

    1989-08-01

    Method and apparatus are provided for coupling a temporally short electric power pulse from a thick flat-conductor power cable into a thin flat-conductor slapper detonator circuit. A first planar and generally circular loop is formed from an end portion of the power cable. A second planar and generally circular loop, of similar diameter, is formed from all or part of the slapper detonator circuit. The two loops are placed together, within a ferrite housing that provides a ferrite path that magnetically couples the two loops. Slapper detonator parts may be incorporated within the ferrite housing. The ferrite housing may be made vacuum and water-tight, with the addition of a hermetic ceramic seal, and provided with an enclosure for protecting the power cable and parts related thereto. 10 figs.

  20. Controlled ferrite content improves weldability of corrosion-resistant steel

    NASA Technical Reports Server (NTRS)

    Malin, C. O.

    1967-01-01

    Corrosion-resistant steel that adds restrictions on chemical composition to ensure sufficient ferrite content decreases the tendency of CRES to develop cracks during welding. The equations restricting composition are based on the Schaeffler constitution diagram.

  1. Sustainable synthesis of monodispersed spinel nano-ferrites

    EPA Science Inventory

    A sustainable approach for the synthesis of various monodispersed spinel ferrite nanoparticles has been developed that occurs at water-toluene interface under both conventional and microwave hydrothermal conditions. This general synthesis procedure utilizes readily available and ...

  2. Charpy impact test results for low-activation ferritic alloys

    SciTech Connect

    Cannon, N.S.; Hu, W.L.; Gelles, D.S.

    1987-05-01

    The objective of this work is to evaluate the shift of the ductile to brittle transition temperature (DBTT) and the reduction of the upper shelf energy (USE) due to neutron irradiation of low activation ferritic alloys. Six low activation ferritic alloys have been tested following irradiation at 365/sup 0/C to 10 dpa and compared with control specimens in order to assess the effect of irradiation on Charpy impact properties.

  3. DARHT-II Injector Transients and the Ferrite Damper

    SciTech Connect

    Waldron, Will; Reginato, Lou; Chow, Ken; Houck, Tim; Henestroza, Enrique; Yu, Simon; Kang, Michael; Briggs, Richard

    2006-08-04

    This report summarizes the transient response of the DARHT-II Injector and the design of the ferrite damper. Initial commissioning of the injector revealed a rise time excited 7.8 MHz oscillation on the diode voltage and stalk current leading to a 7.8 MHz modulation of the beam current, position, and energy. Commissioning also revealed that the use of the crowbar to decrease the voltage fall time excited a spectrum of radio frequency modes which caused concern that there might be significant transient RF electric field stresses imposed on the high voltage column insulators. Based on the experience of damping the induction cell RF modes with ferrite, the concept of a ferrite damper was developed to address the crowbar-excited oscillations as well as the rise-time-excited 7.8 MHz oscillations. After the Project decided to discontinue the use of the crowbar, further development of the concept focused exclusively on damping the oscillations excited by the rise time. The design was completed and the ferrite damper was installed in the DARHT-II Injector in February 2006. The organization of this report is as follows. The suite of injector diagnostics are described in Section 2. The data and modeling of the injector transients excited on the rise-time and also by the crowbar are discussed in Section 3; the objective is a concise summary of the present state of understanding. The design of the ferrite damper, and the small scale circuit simulations used to evaluate the ferrite material options and select the key design parameters like the cross sectional area and the optimum gap width, are presented in Section 4. The details of the mechanical design and the installation of the ferrite damper are covered in Section 5. A brief summary of the performance of the ferrite damper following its installation in the injector is presented in Section 6.

  4. MHD Effects of a Ferritic Wall on Tokamak Plasmas

    NASA Astrophysics Data System (ADS)

    Hughes, Paul E.

    It has been recognized for some time that the very high fluence of fast (14.1MeV) neutrons produced by deuterium-tritium fusion will represent a major materials challenge for the development of next-generation fusion energy projects such as a fusion component test facility and demonstration fusion power reactor. The best-understood and most promising solutions presently available are a family of low-activation steels originally developed for use in fission reactors, but the ferromagnetic properties of these steels represent a danger to plasma confinement through enhancement of magnetohydrodynamic instabilities and increased susceptibility to error fields. At present, experimental research into the effects of ferromagnetic materials on MHD stability in toroidal geometry has been confined to demonstrating that it is still possible to operate an advanced tokamak in the presence of ferromagnetic components. In order to better quantify the effects of ferromagnetic materials on tokamak plasma stability, a new ferritic wall has been installated in the High Beta Tokamak---Extended Pulse (HBT-EP) device. The development, assembly, installation, and testing of this wall as a modular upgrade is described, and the effect of the wall on machine performance is characterized. Comparative studies of plasma dynamics with the ferritic wall close-fitting against similar plasmas with the ferritic wall retracted demonstrate substantial effects on plasma stability. Resonant magnetic perturbations (RMPs) are applied, demonstrating a 50% increase in n = 1 plasma response amplitude when the ferritic wall is near the plasma. Susceptibility of plasmas to disruption events increases by a factor of 2 or more with the ferritic wall inserted, as disruptions are observed earlier with greater frequency. Growth rates of external kink instabilities are observed to be twice as large in the presence of a close-fitting ferritic wall. Initial studies are made of the influence of mode rotation frequency

  5. Molecular and functional identification of three interleukin-17A/F (IL-17A/F) homologues in large yellow croaker (Larimichthys crocea).

    PubMed

    Ding, Yang; Ao, Jingqun; Ai, Chunxiang; Chen, Xinhua

    2016-02-01

    The interleukin-17 (IL-17) cytokine family plays a central role in the coordination of inflammatory responses. In fish species, three genes that have a similar homology to both IL-17A and IL-17F were designated IL-17A/F1, 2, and 3. In this study, we identified three IL-17A/F homologues (LycIL-17A/F1, 2, and 3) from large yellow croaker (Larimichthys crocea). The deduced LycIL-17A/F1 and 3 had four cysteine residues conserved in teleost IL-17A/F1 and 3 homologues and shared a domain similar to the B chain of human IL-17F. The deduced LycIL-17A/F2 possessed the unique arrangement of six cysteine residues as teleost IL-17A/F2 (except Fugu IL-17A/F2) and higher vertebrate IL-17A and F, and shared a domain similar to the D/E chain of human IL-17A. Phylogenetic analysis showed that teleost IL-17A/F1 and 3 fall into a major clade, whereas IL-17A/F2 forms a separated clade and is clustered with IL-17N. Based on structural and phylogenetic analyses, we suggest that teleost IL-17A/Fs may be classified into two subgroups: one consisting of IL-17A/F1 and 3, and the other composed of IL-17A/F2. The three LycIL-17A/Fs were constitutively expressed in all tissues examined although at a different level. Following challenge with Aeromonas hydrophila, expression of these three LycIL-17A/Fs was rapidly increased in head kidney and gills. The in vivo assays showed that recombinant LycIL-17A/F1, 2, and 3 all were able to enhance the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α2), chemokines (CXCL8 and CXCL13), and antimicrobial peptide hepcidin in head kidney. Furthermore, LycIL-17A/Fs appeared to mediate pro-inflammatory responses via NF-κB signalling. These results therefore reveal similar functions between the two subgroup members,LycIL-17A/F1 and 3 and LycIL-17A/F2, in promoting inflammation and host defences. PMID:26429410

  6. Ongoing Ferritic Wall Mode studies on HBT-EP

    NASA Astrophysics Data System (ADS)

    Hughes, P. E.; Mauel, M. E.; Levesque, J. P.; Navratil, G. A.

    2015-11-01

    Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective US component test facility and DEMO. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these experiments. Although the ferritic wall mode (FWM) was seen in a linear machine, ferritic steel was observed to be compatible with high-performance operation in JFT-2M. Using its high-resolution magnetic diagnostics and adjustable wall segments, HBT-EP now operates successfully with a high-permeability tiled ferritic first wall. Initial measurements showed the ferritic wall enhances the growth rate of the m/n = 3/1 kink mode. In this poster, we report results of our study of the evolution of naturally rotating modes, increased plasma response to phase-flip resonant magnetic perturbations (RMPs), and enhanced plasma disruptivity as the walls are adjusted from stainless wall to ferritic wall configuration. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  7. Preparation of high-permeability NiCuZn ferrite*

    PubMed Central

    Hu, Jun; Yan, Mi

    2005-01-01

    Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature of NiZn ferrite from 1200 °C to 930 °C. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 °C is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 °C because the microstructure of the NiZn ferrite sintered at 930 °C is more uniform and compact than that of the NiZn ferrite sintered at 1200 °C. The high permeability of 1700 and relative loss coefficient tanδ/μi of 9.0×10−6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite. PMID:15909348

  8. Epitaxial single crystalline ferrite films for high frequency applications

    SciTech Connect

    Suzuki, Y.; Dover, R.B. van; Korenivski, V.; Werder, D.; Chen, C.H.; Felder, R.J.; Phillips, J.M.

    1996-11-01

    The successful growth of single crystal ferrites in thin film form is an important step towards their future incorporation into integrated circuits operating at microwave frequencies. The authors have successfully grown high quality single crystalline spinel ferrite thin films of (Mn,Zn)Fe{sub 2}O{sub 4} and CoFe{sub 2}O{sub 4} on (100) and (110) SrTiO{sub 3} and MgAl{sub 2}O{sub 4} at low temperature. These ferrite films are buffered with spinel structure layers that are paramagnetic at room temperature. In contrast to ferrite films grown directly on the substrates, ferrite films grown on buffered substrates exhibit excellent crystallinity and bulk saturation magnetization values, thus indicating the importance of lattice match and structural similarity between the film and the immediately underlying layer. X-ray, RBS, AFM and TEM analysis provide a consistent picture of the structural properties of these ferrite films. The authors then use this technique to grow exchange-coupled bilayers of single crystalline CoFe{sub 2}O{sub 4} and (Mn,Zn)Fe{sub 2}O{sub 4}. In these bilayers, they observe strong exchange coupling across the interface that is similar in strength to the exchange coupling in the individual layers.

  9. Exchange-spring mechanism of soft and hard ferrite nanocomposites

    SciTech Connect

    Manjura Hoque, S.; Srivastava, C.; Kumar, V.; Venkatesh, N.; Das, H.N.; Saha, D.K.; Chattopadhyay, K.

    2013-08-01

    Graphical abstract: - Highlights: • Exchange-spring behaviour of soft and hard ferrites was studied. • XRD patterns indicated soft and hard ferrites as fcc and hcp structure. • Hysteresis loops indicate wide difference in coercivity of soft and hard phases. • Nanocomposites produced convex hysteresis loop characteristic of single-phase. - Abstract: The paper reports exchange-spring soft and hard ferrite nanocomposites synthesized by chemical co-precipitation with or without the application of ultrasonic vibration. The composites contained BaFe{sub 12}O{sub 19} as the hard phase and CoFe{sub 2}O{sub 4}/MgFe{sub 2}O{sub 4} as the soft phase. X-ray diffraction patterns of the samples in the optimum calcined condition indicated the presence of soft ferrites as face-centred cubic (fcc) and hard ferrites as hexagonal close packed (hcp) structure respectively. Temperature dependence of magnetization in the range of 20–700 °C demonstrated distinct presence of soft and hard ferrites as magnetic phases which are characterized by wide difference in magnetic anisotropy and coercivity. Exchange-spring mechanism led these nanocomposite systems to exchange-coupled, which ultimately produced convex hysteresis loops characteristic of a single-phase permanent magnet. Fairly high value of coercivity and maximum energy product were observed for the samples in the optimum calcined conditions with a maximum applied field of 1600 kA/m (2 T)

  10. Kinetics of Ferrite Recrystallization and Austenite Formation During Intercritical Annealing of the Cold-Rolled Ferrite/Martensite Duplex Structures

    NASA Astrophysics Data System (ADS)

    Mazaheri, Y.; Kermanpur, A.; Najafizadeh, A.; Kalashami, A. Ghatei

    2016-03-01

    Ultrafine-grained, dual-phase (UFG DP) steels were produced by a new route using an uncommon cold-rolling and subsequent intercritical annealing of ferrite/martensite duplex starting microstructures. The effects of processing parameters such as rolling reduction, intercritical annealing temperature, and time on the microstructural evaluations have been studied. UFG DP steels with an average grain size of about 1 to 2 μm were achieved by short intercritical annealing of the 80 pct cold-rolled duplex microstructures. The kinetics of ferrite recrystallization and austenite formation were studied based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. The proposed model for describing the isothermal austenite formation kinetics was applied successfully to the nonisothermal conditions. It was found that complete recrystallization of ferrite before the austenite formation led to the formation of a large extent randomly distributed austenite in the ferrite matrix and a chain-networked structure.

  11. An Empirical Test of Oklahoma's A-F School Grades

    ERIC Educational Resources Information Center

    Adams, Curt M.; Forsyth, Patrick B.; Ware, Jordan; Mwavita, Mwarumba; Barnes, Laura L.; Khojasteb, Jam

    2016-01-01

    Oklahoma is one of 16 states electing to use an A-F letter grade as an indicator of school quality. On the surface, letter grades are an attractive policy instrument for school improvement; they are seemingly clear, simple, and easy to interpret. Evidence, however, on the use of letter grades as an instrument to rank and improve schools is scant…

  12. R2 AIRS/AFS FACILITY GIS LAYER

    EPA Science Inventory

    The AFS subsystem contains emissions, compliance, and permit data for stationary sources regulated by the U.S. EPA and state and local air pollution agencies. This information is used by states in preparation of State Implementation Plans (SIPs), to track the compliance status ...

  13. R2 AIRS/AFS PERMITS GIS LAYER

    EPA Science Inventory

    The Region 2 AIRS/AFS Permits Regulated Facility GIS layer contains identification (name, address, ID), and location (latitude, longitude, and locational metadata), attributes of stationary source(s) of air pollution associated with facilities that are regulated by the U. S. EPA....

  14. Treatment Guidelines of Atrial Fibrillation (AFib or AF)

    MedlinePlus

    ... Pressure Tools & Resources Stroke More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 23,2016 What ... content was last reviewed on 04/16/14. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  15. Extracting uranium from seawater: Promising AF series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.

  16. Extracting uranium from seawater: Promising AF series adsorbents

    DOE PAGESBeta

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8more » ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.« less

  17. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2010-07-01 2010-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  18. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2011-07-01 2011-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  19. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2013-07-01 2013-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  20. Development of ferritic weldments for grain-refined ferritic steels for 4. 2K service

    SciTech Connect

    Kim, H.J.

    1982-11-01

    The weldability of grain-refined ferritic nickel steels designed for structural use in liquid helium was investigated. Plates of interstitial-free Fe-12Ni-0.25Ti alloy and carbon-containing 9 Ni steel were welded with 14 Ni ferritic fillers using a gas tungsten arc welding (GTAW) process with pure argon gas shielding. The ferritic weldments made have a strength closely matching those of the base plates without a significant loss in base metal toughness at temperatures as low as 4.2 K. The comparable toughness obtained in the welded region is attributed to three factors; the defect-free weldment, the chemical cleanliness of the GTAW weld deposit, and the in-process formation of an appropriate microstructure in the welded region. Special emphasis in this study was placed on changes in microstructures with respect to the characteristic of the weld thermal cycles and the effect of the resultant microstructures on low temperature toughness. In the heat-affected zone (HAZ) of multipass welded 9Ni steel, the retained (or precipitated) austenite is removed by the weld heat cycles but the sequential rapid heat cycles to successively lower peak temperatures associated with succeeding weld passes re-establish high toughness by sequentially refining the grain size and gettering carbon in the form of cementite precipitates. On the other hand, the high toughness in the HAZ of the 12Ni alloy and in the weld deposit is a direct consequence of repeated grain refinement through the overlapped austenitizing cycles and is not affected by the tempering cycles because of the carbon-free nature of these materials. 46 figures.

  1. Development of ferritic weldments for grain-refined ferritic steels for 4. 2K service

    SciTech Connect

    Kim, H.J.

    1982-01-01

    The weldability of grain-refined ferritic nickel steels designed for structural use in liquid helium was investigated. Plates of interstitial-free Fe-12Ni-0.25Ti alloy and carbon-containing 9Ni steel were welded with 14Ni ferritic fillers using a gas tungsten arc welding (GTAW) process with pure argon gas shielding. The ferritic weldments made have a strength closely matching those of the base plates without a significant loss in base metal toughness at temperatures as low as 4.2K. The comparable toughness obtained in the welded region is attributed to three factors; the defect-free weldment, the chemical cleanliness of the GTAW weld deposit, and the in-process formation of an appropriate microstructure in the welded region. Special emphasis in this study was placed on changes in microstructures with respect to the characteristic of the weld thermal cycles and the effect of the resultant microstructures on low temperature toughness. In the heat-affected zone (HAZ) of multipass welded 9Ni steel, the retained (or precipitated) austenite is removed by the weld heat cycles but the sequential rapid heat cycles to successively lower peak temperatures associated with succeeding weld passes re-establish high toughness by sequentially refining the grain size and gettering carbon in the form of cementite precipitates. On the other hand, the high toughness in the HAZ of the 12Ni alloy and in the weld deposit is a direct consequence of repeated grain refinement through the overlapped austenitizing cycles and is not affected by the tempering cycles because of the carbon-free nature of these materials.

  2. Lift-Off Performance of Ferrite Enhanced Generation Emats

    NASA Astrophysics Data System (ADS)

    Fan, Yichao; Dixon, Steve; Jian, Xiaoming

    2008-02-01

    Electromagnetic Acoustic Transducers (EMATs) are non-contact ultrasonic transducers capable of generating wide-band ultrasonic waves on electrically conductive and magnetostrictive samples. The lack of physical contact makes EMATs particularly suitable for online inspection applications, or situations where samples may be moving or hot. The generation efficiency of a given EMAT on a given sample is dependent on the "lift-off", which is the distance between the EMAT and the sample surface. Efficiency dramatically reducing with increased lift-off. This requirement to be in close proximity to the sample imposes a practical limit of operation and changes in lift-off due to phenomena such as sample vibration can have practical implications in certain NDE applications. This paper describes some results from experiments comparing the performance of a ferrite enhanced EMAT design to one of our `standard' EMATs, where we have substituted the permanent magnet from the standard EMAT with a suitable ferrite material. When the EMAT coil is placed in proximity to the ferrite, but not wrapped around the ferrite, the increase in the generated eddy current amplitude is significant, whilst the inductance or bandwidth of the EMAT is not significantly affected. Using a ferrite material eliminated eddy current losses in the permanent magnet, and also enhances the self-field generation mechanism, which generates a repulsive normal force on the sample surface. Direct experimental results show the ferrite enhanced EMAT generation efficiency can be higher at large stand-offs and is also less sensitive to lift-off variations. Although the example we describe here only applies to EMAT generation, there are situations where ferrite could be used to enhance detector efficiencies.

  3. Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

    NASA Technical Reports Server (NTRS)

    Willis, Peter; Hunt, Brian; White,Victor; Grunthaner, Frank

    2008-01-01

    A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013. Fabrication processes have been developed to make the microfabricated Teflon-AF microfluidic diaphragm pumps capable of surviving extreme temperature excursions before and after exposure to liquid water. Two glass wafers are etched with features and a continuous Teflon membrane is sandwiched between them (see figure). Single valves are constructed using this geometry. The microfabricated devices are then post processed by heating the assembled device while applying pneumatic pressure to force the Teflon diaphragm against the valve seat while it is softened. After cooling the device, the embossed membrane retains this new shape. This solves previous problems with bubble introduction into the fluid flow where deformations of the membrane at the valve seat occurred during device bonding at elevated temperatures (100-150 C). The use of laminated membranes containing commercial Teflon AF 2400 sheet sandwiched between spun Teflon AF 1600 layers performed best, and were less gas permeable than Teflon AF 1600 membranes on their own. Spinning Teflon AF 1600 solution (6 percent in FLOURINERT(Registered TradeMark) FC40 solvent, 3M Company) at 500 rpm for 1.5 seconds, followed by 1,000 rpm for 3 seconds onto Borofloat glass wafers, results in a 10-micron-thick film of extremely smooth Teflon AF. This spinning process is repeated several times on flat, blank, glass wafers in order to gradually build a thick, smooth membrane. After running this process at least five times, the wafer and Teflon coating are heated under vacuum

  4. Synthesis of Novel Ferrite Based Recyclable Catalyst Used to Clean Dye and Emerging Contaminates from Water

    EPA Science Inventory

    Herein, we describe synthesis of novel palladium, copper, cobalt and vanadium ferrites. The ferrites were synthesized by combustion method using polyvinyl alcohol. The particles phases were confirmed using X-ray diffraction and sizes were determined using particle size analyzer. ...

  5. Unraveling the Effect of Thermomechanical Treatment on the Dissolution of Delta Ferrite in Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Rezayat, Mohammad; Mirzadeh, Hamed; Namdar, Masih; Parsa, Mohammad Habibi

    2016-02-01

    Considering the detrimental effects of delta ferrite stringers in austenitic stainless steels and the industrial considerations regarding energy consumption, investigating, and optimizing the kinetics of delta ferrite removal is of vital importance. In the current study, a model alloy prone to the formation of austenite/delta ferrite dual phase microstructure was subjected to thermomechanical treatment using the wedge rolling test aiming to dissolve delta ferrite. The effect of introducing lattice defects and occurrence of dynamic recrystallization (DRX) were investigated. It was revealed that pipe diffusion is responsible for delta ferrite removal during thermomechanical process, whereas when the DRX is dominant, the kinetics of delta ferrite dissolution tends toward that of the static homogenization treatment for delta ferrite removal that is based on the lattice diffusion of Cr and Ni in austenite. It was concluded that the optimum condition for dissolution of delta ferrite can be defined by the highest rolling temperature and strain in which DRX is not pronounced.

  6. Towards Radiation Tolerant Nanostructured Ferritic Alloys

    SciTech Connect

    Miller, Michael K; Hoelzer, David T; Russell, Kaye F

    2010-01-01

    The high temperature and irradiation response of a new class of nanostructured ferritic alloys have been investigated by atom probe tomography. These materials are candidate materials for use in the extreme environments that will be present in the next generation of power generating systems. Atom probe tomography has revealed that the yttria powder is forced into solid solution during the mechanical alloying process andsubsequently 2-nm-diameter Ti-, Y- and O-enriched nanoclusters are formedduring the extrusion process. These nanoclusters have been shown to be remarkably stable during isothermal annealing treatments up to 0.92 of the melting temperature and during proton irradiation up to 3 displacements per atom. No significant difference in sizes, compositions and number densities of the nanoclusters was also observed between the unirradiated and proton irradiated conditions. The grain boundaries were found to have high number densities of nanoclusters as well as chromium and tungsten segregation which pin the grain boundary to minimize creep and grain growth.

  7. Development of low activation Ferritic steels

    NASA Astrophysics Data System (ADS)

    Noda, T.; Abe, F.; Araki, H.; Okada, M.

    1986-11-01

    Fe-(2-15)%Cr-(0-4)%W-0.1%C and Fe-9%Cr-(0-l)%V-0.1%C steels were prepared on the basis of reduced activation of ferritic steels. Tempering characteristics of these alloys were studied as a preliminary evaluation of mechanical properties. Alloys except for 12-15%Cr, 9%Cr-4%W, and 9%Cr-1%V showed a single phase of martensite. Carbides which precipitated in as-tempered steels are M 23C 6, M 6C, and W 2C for Cr-W steels and M 23C 6 and V 4C 3 for Cr-V steels. The toughness of the alloys was examined with Charpy impact test. The minimum DBTT (ductile-brittle transition temperature) was observed at around 0.25 at% of W or V concentration for 9%Cr steels. 9%Cr-V steels were superior to commercial 9%Cr-2%Mo steel in the point of toughness. The order of alloying element with a low DBTT was V > Mo > W.

  8. Spinel cobalt ferrite by complexometric synthesis

    NASA Astrophysics Data System (ADS)

    Thang, Pham D.; Rijnders, Guus; Blank, Dave H. A.

    2005-09-01

    Magnetic fine particles of cobalt ferrite (CoFe 2O 4) have been synthesized using complexometric method in which ethylene diamine tetra acetic acid C 10H 16N 2O 8 (EDTA) acts as a complexing agent. The crystallographic structure, microstructure and magnetic properties of the synthesized powder were characterized by using X-ray diffraction (XRD), particle size analysis and vibrating sample magnetometry (VSM). The material crystallized in cubic spinel structure with lattice parameter of about 8.38 Å. Depending on the calcining temperature, the particle size of the powders varies in the range of hundreds of nanometers to tens of micrometers. A desired relative density above 95% of the theoretical value is obtained for the bulk sample after sintering. The calcined powders and sintered sample exhibit saturation magnetizations around 80 Am 2/kg which is expected for inverse CoFe 2O 4. With increasing calcining temperature the coercivity of these samples decreases. This simple synthesis route leads to a reproducible and stoichiometric material.

  9. A biosensor system using nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Singh, Prachi; Rathore, Deepshikha

    2016-05-01

    NiFe2O4 ferrite nanoparticles were synthesized by chemical co-precipitation method and the structural characteristics were investigated using X-ray diffraction technique, where single cubic phase formation of nanoparticles was confirmed. The average particle size of NiFe2O4 was found to be 4.9 nm. Nanoscale magnetic materials are an important source of labels for biosensing due to their strong magnetic properties which are not found in biological systems. This property of the material was exploited and the fabrication of the NiFe2O4 nanoparticle based biosensor was done in the form of a capacitor system, with NiFe2O4 as the dielectric material. The biosensor system was tested towards different biological materials with the help of electrochemical workstation and the same was analysed through Cole-Cole plot of NiFe2O4. The performance of the sensor was determined based on its sensitivity, response time and recovery time.

  10. Must we use ferritic steel in TBM?

    SciTech Connect

    Salavy, Jean-Francois; Boccaccini, Lorenzo V.; Chaudhuri, Paritosh; Cho, Seungyon; Enoeda, Mikio; Giancarli, Luciano; Kurtz, Richard J.; Luo, Tian Y.; Rao, K. Bhanu Sankara; Wong, Clement

    2010-12-13

    Mock-ups of DEMO breeding blankets, called Test Blanket Modules (TBMs), inserted and tested in ITER in dedicated equatorial ports directly facing the plasma, are expected to provide the first experimental answers on the necessary performance of the corresponding DEMO breeding blankets. Several DEMO breeding blanket designs have been studied and assessed in the last 20 years. At present, after considering various coolant and breeder combinations, all the TBM concepts proposed by the seven ITER Parties use Reduced-Activation Ferritic/Martensitic (RAFM) steel as the structural material. In order to perform valuable tests in ITER, the TBMs are expected to use the same structural material as corresponding DEMO blankets. However, due to the fact that this family of steels is ferromagnetic, their presence in the ITER vacuum vessel will create perturbations of the ITER magnetic fields that could reduce the quality of the plasma confinement during H-mode. As a consequence, a legitimate question has been raised on the necessity of using RAFM steel for TBMs structural material in ITER. By giving a short description of the main TBM testing objectives in ITER and assessing the consequences of not using such a material, this paper gives a comprehensive answer to this question. According to the working group author of the study, the use of RAFM steel as structural material for TBM is judged mandatory.

  11. Energy of domain walls in ferrite films

    NASA Astrophysics Data System (ADS)

    Gomez, M. E.; Prieto, P.; Mendoza, A.; Guzman, O.

    2007-03-01

    MnZn Ferrite films were deposited by RF sputtering on (001) single crystal MgO substrates. AFM images show an increment in grain size with the film thickness. Grains with diameter between φ ˜ 70 and 700 nm have been observed. The coercive field Hc as a function of the grain size reaches a maximum value of about 80 Oe for φc˜ 300 nm. The existence of a multidomain structure associated with a critical grain size was identified by Magneto-optical Kerr effect technique (MOKE). The transition of the one-domain regime to the two-domain regime was observed at a critical grain size of Dc˜ 530 nm. This value agree with values predicted previously. The Jiles-Atherton model (JAM) was used to discuss the experimental hysteresis loops. The k pinning parameter obtained from JAM shows a maximum value of k/μo = 67 Am^2 for grains with Lc˜ 529 nm. The total energy per unit area E was correlated with k and D. We found a simple phenomenological relationship given by E α kD; where D is the magnetic domain width.

  12. Development of advanced barium ferrite tape media

    NASA Astrophysics Data System (ADS)

    Shimizu, Osamu; Oyanagi, Masahito; Morooka, Atsushi; Mori, Masahiko; Kurihashi, Yuich; Tada, Toshio; Suzuki, Hiroyuki; Harasawa, Takeshi

    2016-02-01

    We developed an advanced particulate magnetic tape using fine barium ferrite (BaFe) particles for magnetic-tape storage systems. The new tape showed a signal-to-noise ratio (SNR) that was 3.5 dB higher than that of the commercially available BaFe tape used for the Linear Tape Open generation 6 tape-storage system, at a linear density of 300 kfci measured with a giant magnetoresistive head with a reader width of 0.45 μm. Such significant increase in SNR was achieved by reducing the magnetic particle volume from 1950 to 1350 nm3, while maintaining a sufficiently high thermal stability, improving the perpendicular squareness ratio from 0.66 to 0.83, and improving the surface roughness from 2.5 to 2.0 nm when measured by atomic force microscopy and from 2.4 to 0.9 nm when measured by optical interferometry. This paper describes the characteristics of the new BaFe particles and media, which are expected to be employed for future high-capacity linear-tape systems.

  13. Feedback controlled hybrid fast ferrite tuners

    SciTech Connect

    Remsen, D.B.; Phelps, D.A.; deGrassie, J.S.; Cary, W.P.; Pinsker, R.I.; Moeller, C.P.; Arnold, W.; Martin, S.; Pivit, E.

    1993-09-01

    A low power ANT-Bosch fast ferrite tuner (FFT) was successfully tested into (1) the lumped circuit equivalent of an antenna strap with dynamic plasma loading, and (2) a plasma loaded antenna strap in DIII-D. When the FFT accessible mismatch range was phase-shifted to encompass the plasma-induced variation in reflection coefficient, the 50 {Omega} source was matched (to within the desired 1.4 : 1 voltage standing wave ratio). The time required to achieve this match (i.e., the response time) was typically a few hundred milliseconds, mostly due to a relatively slow network analyzer-computer system. The response time for the active components of the FFT was 10 to 20 msec, or much faster than the present state-of-the-art for dynamic stub tuners. Future FFT tests are planned, that will utilize the DIII-D computer (capable of submillisecond feedback control), as well as several upgrades to the active control circuit, to produce a FFT feedback control system with a response time approaching 1 msec.

  14. Chemical looping coal gasification with calcium ferrite and barium ferrite via solid--solid reactions

    SciTech Connect

    Siriwardane, Ranjani; Tian, Hanjing; Richards, George

    2016-01-01

    Coal gasification to produce synthesis gas by chemical looping was investigated with two oxygen carriers, barium ferrite (BaFe2O4) and calcium ferrite (CaFe2O4). Thermo-gravimetric analysis (TGA) and fixed-bed flow reactor data indicated that a solid–solid interaction occurred between oxygen carriers and coal to produce synthesis gas. Both thermodynamic analysis and experimental data indicated that BaFe2O4 and CaFe2O4 have high reactivity with coal but have a low reactivity with synthesis gas, which makes them very attractive for the coal gasification process. Adding steam increased the production of hydrogen (H2) and carbon monoxide (CO), but carbon dioxide (CO2) remained low because these oxygen carriers have minimal reactivity with H2 and CO. Therefore, the combined steam–oxygen carrier produced the highest quantity of synthesis gas. It appeared that neither the water–gas shift reaction nor the water splitting reaction promoted additional H2 formation with the oxygen carriers when steam was present. Wyodak coal, which is a sub-bituminous coal, had the best gasification yield with oxygen carrier–steam while Illinois #6 coal had the lowest. The rate of gasification and selectivity for synthesis gas production was significantly higher when these oxygen carriers were present during steam gasification of coal. The rates and synthesis gas yields during the temperature ramps of coal–steam with oxygen carriers were better than with gaseous oxygen.

  15. Ferritic Alloys with Extreme Creep Resistance via Coherent Hierarchical Precipitates

    NASA Astrophysics Data System (ADS)

    Song, Gian; Sun, Zhiqian; Li, Lin; Xu, Xiandong; Rawlings, Michael; Liebscher, Christian H.; Clausen, Bjørn; Poplawsky, Jonathan; Leonard, Donovan N.; Huang, Shenyan; Teng, Zhenke; Liu, Chain T.; Asta, Mark D.; Gao, Yanfei; Dunand, David C.; Ghosh, Gautam; Chen, Mingwei; Fine, Morris E.; Liaw, Peter K.

    2015-11-01

    There have been numerous efforts to develop creep-resistant materials strengthened by incoherent particles at high temperatures and stresses in response to future energy needs for steam turbines in thermal-power plants. However, the microstructural instability of the incoherent-particle-strengthened ferritic steels limits their application to temperatures below 900 K. Here, we report a novel ferritic alloy with the excellent creep resistance enhanced by coherent hierarchical precipitates, using the integrated experimental (transmission-electron microscopy/scanning-transmission-electron microscopy, in-situ neutron diffraction, and atom-probe tomography) and theoretical (crystal-plasticity finite-element modeling) approaches. This alloy is strengthened by nano-scaled L21-Ni2TiAl (Heusler phase)-based precipitates, which themselves contain coherent nano-scaled B2 zones. These coherent hierarchical precipitates are uniformly distributed within the Fe matrix. Our hierarchical structure material exhibits the superior creep resistance at 973 K in terms of the minimal creep rate, which is four orders of magnitude lower than that of conventional ferritic steels. These results provide a new alloy-design strategy using the novel concept of hierarchical precipitates and the fundamental science for developing creep-resistant ferritic alloys. The present research will broaden the applications of ferritic alloys to higher temperatures.

  16. Ferritic Alloys with Extreme Creep Resistance via Coherent Hierarchical Precipitates

    PubMed Central

    Song, Gian; Sun, Zhiqian; Li, Lin; Xu, Xiandong; Rawlings, Michael; Liebscher, Christian H.; Clausen, Bjørn; Poplawsky, Jonathan; Leonard, Donovan N.; Huang, Shenyan; Teng, Zhenke; Liu, Chain T.; Asta, Mark D.; Gao, Yanfei; Dunand, David C.; Ghosh, Gautam; Chen, Mingwei; Fine, Morris E.; Liaw, Peter K.

    2015-01-01

    There have been numerous efforts to develop creep-resistant materials strengthened by incoherent particles at high temperatures and stresses in response to future energy needs for steam turbines in thermal-power plants. However, the microstructural instability of the incoherent-particle-strengthened ferritic steels limits their application to temperatures below 900 K. Here, we report a novel ferritic alloy with the excellent creep resistance enhanced by coherent hierarchical precipitates, using the integrated experimental (transmission-electron microscopy/scanning-transmission-electron microscopy, in-situ neutron diffraction, and atom-probe tomography) and theoretical (crystal-plasticity finite-element modeling) approaches. This alloy is strengthened by nano-scaled L21-Ni2TiAl (Heusler phase)-based precipitates, which themselves contain coherent nano-scaled B2 zones. These coherent hierarchical precipitates are uniformly distributed within the Fe matrix. Our hierarchical structure material exhibits the superior creep resistance at 973 K in terms of the minimal creep rate, which is four orders of magnitude lower than that of conventional ferritic steels. These results provide a new alloy-design strategy using the novel concept of hierarchical precipitates and the fundamental science for developing creep-resistant ferritic alloys. The present research will broaden the applications of ferritic alloys to higher temperatures. PMID:26548303

  17. Ferritic Alloys with Extreme Creep Resistance via Coherent Hierarchical Precipitates

    DOE PAGESBeta

    Song, Gian; Sun, Zhiqian; Li, Lin; Xu, Xiandong; Rawlings, Michael; Liebscher, Christian H.; Clausen, Bjørn; Poplawsky, Jonathan; Leonard, Donovan N.; Huang, Shenyan; et al

    2015-11-09

    There have been numerous efforts to develop creep-resistant materials strengthened by incoherent particles at high temperatures and stresses in response to future energy needs for steam turbines in thermal-power plants. However, the microstructural instability of the incoherent-particle-strengthened ferritic steels limits their application to temperatures below 900 K. Here, we report a novel ferritic alloy with the excellent creep resistance enhanced by coherent hierarchical precipitates, using the integrated experimental (transmission-electron microscopy/scanning-transmission-electron microscopy, in-situ neutron diffraction, and atom-probe tomography) and theoretical (crystal-plasticity finite-element modeling) approaches. This alloy is strengthened by nano-scaled L21-Ni2TiAl (Heusler phase)-based precipitates, which themselves contain coherent nano-scaled B2 zones.more » These coherent hierarchical precipitates are uniformly distributed within the Fe matrix. Our hierarchical structure material exhibits the superior creep resistance at 973 K in terms of the minimal creep rate, which is four orders of magnitude lower than that of conventional ferritic steels. These results provide a new alloy-design strategy using the novel concept of hierarchical precipitates and the fundamental science for developing creep-resistant ferritic alloys. Finally, the present research will broaden the applications of ferritic alloys to higher temperatures.« less

  18. Ferritic Alloys with Extreme Creep Resistance via Coherent Hierarchical Precipitates

    SciTech Connect

    Song, Gian; Sun, Zhiqian; Li, Lin; Xu, Xiandong; Rawlings, Michael; Liebscher, Christian H.; Clausen, Bjørn; Poplawsky, Jonathan; Leonard, Donovan N.; Huang, Shenyan; Teng, Zhenke; Liu, Chain T.; Asta, Mark D.; Gao, Yanfei; Dunand, David C.; Ghosh, Gautam; Chen, Mingwei; Fine, Morris E.; Liaw, Peter K.

    2015-11-09

    There have been numerous efforts to develop creep-resistant materials strengthened by incoherent particles at high temperatures and stresses in response to future energy needs for steam turbines in thermal-power plants. However, the microstructural instability of the incoherent-particle-strengthened ferritic steels limits their application to temperatures below 900 K. Here, we report a novel ferritic alloy with the excellent creep resistance enhanced by coherent hierarchical precipitates, using the integrated experimental (transmission-electron microscopy/scanning-transmission-electron microscopy, in-situ neutron diffraction, and atom-probe tomography) and theoretical (crystal-plasticity finite-element modeling) approaches. This alloy is strengthened by nano-scaled L21-Ni2TiAl (Heusler phase)-based precipitates, which themselves contain coherent nano-scaled B2 zones. These coherent hierarchical precipitates are uniformly distributed within the Fe matrix. Our hierarchical structure material exhibits the superior creep resistance at 973 K in terms of the minimal creep rate, which is four orders of magnitude lower than that of conventional ferritic steels. These results provide a new alloy-design strategy using the novel concept of hierarchical precipitates and the fundamental science for developing creep-resistant ferritic alloys. Finally, the present research will broaden the applications of ferritic alloys to higher temperatures.

  19. Strong and moldable cellulose magnets with high ferrite nanoparticle content.

    PubMed

    Galland, Sylvain; Andersson, Richard L; Ström, Valter; Olsson, Richard T; Berglund, Lars A

    2014-11-26

    A major limitation in the development of highly functional hybrid nanocomposites is brittleness and low tensile strength at high inorganic nanoparticle content. Herein, cellulose nanofibers were extracted from wood and individually decorated with cobalt-ferrite nanoparticles and then for the first time molded at low temperature (<120 °C) into magnetic nanocomposites with up to 93 wt % inorganic content. The material structure was characterized by TEM and FE-SEM and mechanically tested as compression molded samples. The obtained porous magnetic sheets were further impregnated with a thermosetting epoxy resin, which improved the load-bearing functions of ferrite and cellulose material. A nanocomposite with 70 wt % ferrite, 20 wt % cellulose nanofibers, and 10 wt % epoxy showed a modulus of 12.6 GPa, a tensile strength of 97 MPa, and a strain at failure of ca. 4%. Magnetic characterization was performed in a vibrating sample magnetometer, which showed that the coercivity was unaffected and that the saturation magnetization was in proportion with the ferrite content. The used ferrite, CoFe2O4, is a magnetically hard material, demonstrated by that the composite material behaved as a traditional permanent magnet. The presented processing route is easily adaptable to prepare millimeter-thick and moldable magnetic objects. This suggests that the processing method has the potential to be scaled-up for industrial use for the preparation of a new subcategory of magnetic, low-cost, and moldable objects based on cellulose nanofibers. PMID:25331121

  20. Ferritic Alloys with Extreme Creep Resistance via Coherent Hierarchical Precipitates.

    PubMed

    Song, Gian; Sun, Zhiqian; Li, Lin; Xu, Xiandong; Rawlings, Michael; Liebscher, Christian H; Clausen, Bjørn; Poplawsky, Jonathan; Leonard, Donovan N; Huang, Shenyan; Teng, Zhenke; Liu, Chain T; Asta, Mark D; Gao, Yanfei; Dunand, David C; Ghosh, Gautam; Chen, Mingwei; Fine, Morris E; Liaw, Peter K

    2015-01-01

    There have been numerous efforts to develop creep-resistant materials strengthened by incoherent particles at high temperatures and stresses in response to future energy needs for steam turbines in thermal-power plants. However, the microstructural instability of the incoherent-particle-strengthened ferritic steels limits their application to temperatures below 900 K. Here, we report a novel ferritic alloy with the excellent creep resistance enhanced by coherent hierarchical precipitates, using the integrated experimental (transmission-electron microscopy/scanning-transmission-electron microscopy, in-situ neutron diffraction, and atom-probe tomography) and theoretical (crystal-plasticity finite-element modeling) approaches. This alloy is strengthened by nano-scaled L21-Ni2TiAl (Heusler phase)-based precipitates, which themselves contain coherent nano-scaled B2 zones. These coherent hierarchical precipitates are uniformly distributed within the Fe matrix. Our hierarchical structure material exhibits the superior creep resistance at 973 K in terms of the minimal creep rate, which is four orders of magnitude lower than that of conventional ferritic steels. These results provide a new alloy-design strategy using the novel concept of hierarchical precipitates and the fundamental science for developing creep-resistant ferritic alloys. The present research will broaden the applications of ferritic alloys to higher temperatures. PMID:26548303

  1. Characterization of physically vapor deposited AF2400 thin films

    SciTech Connect

    Chow, R.; Spragge, M.K.; Loomis, G.E.; Rainer, F.; Ward, R.; Thomas, I.M.; Kozlowski, M.R.

    1993-11-01

    Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.

  2. Sinuladiterpenes A-F, new cembrane diterpenes from Sinularia flexibilis.

    PubMed

    Lo, Kuang-Liang; Khalil, Ashraf Taha; Kuo, Yao-Haur; Shen, Ya-Ching

    2009-12-01

    Chromatographic investigation of the octocoral Sinularia flexibilis afforded six new cembrane diterpenes, sinuladiterpenes A-F (1-6, resp.), in addition to four known cembranolides, 11-episinulariolide acetate, 11-dehydrosinulariolide, 11-episinulariolide, and sinulariolide. Their structures were elucidated by spectroscopic analysis, especially 2D-NMR and HR-ESI-MS. Compound 2 exhibited significant in vitro cytotoxic activity against human colon adenocarcinoma (WiDr) cell line. PMID:20020460

  3. 77 FR 60478 - Control of Ferrite Content in Stainless Steel Weld Metal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... COMMISSION Control of Ferrite Content in Stainless Steel Weld Metal AGENCY: Nuclear Regulatory Commission... Ferrite Content in Stainless Steel Weld Metal.'' This guide describes a method that the NRC staff considers acceptable for controlling ferrite content in stainless steel weld metal. Revision 4 updates...

  4. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    SciTech Connect

    Leitnaker, J.M.

    1981-05-05

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 015-0.030 times the volume percent ferrite present in alloy. The formation of chi phase upon aging is controlled by controlling the mo content.

  5. 40 CFR 721.10223 - Styrenyl surface treated manganese ferrite with acrylic ester polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ferrite with acrylic ester polymer (generic). 721.10223 Section 721.10223 Protection of Environment... manganese ferrite with acrylic ester polymer (generic). (a) Chemical substance and significant new uses... manganese ferrite with acrylic ester polymer (PMN P-09-582) is subject to reporting under this section...

  6. Durable Superhydrophobic Surfaces via Spontaneous Wrinkling of Teflon AF.

    PubMed

    Scarratt, Liam R J; Hoatson, Ben S; Wood, Elliot S; Hawkett, Brian S; Neto, Chiara

    2016-03-16

    We report the fabrication of both single-scale and hierarchical superhydrophobic surfaces, created by exploiting the spontaneous wrinkling of a rigid Teflon AF film on two types of shrinkable plastic substrates. Sub-100 nm to micrometric wrinkles were reproducibly generated by this simple process, with remarkable control over the size and hierarchy. Hierarchical Teflon AF wrinkled surfaces showed extremely high water repellence (contact angle 172°) and very low contact angle hysteresis (2°), resulting in droplets rolling off the surface at tilt angles lower than 5°. The wrinkling process intimately binds the Teflon AF layer with its substrate, making these surfaces mechanically robust, as revealed by macroscale and nanoscale wear tests: hardness values were close to that of commercial optical lenses and aluminum films, resistance to scratch was comparable to commercial hydrophobic coatings, and damage by extensive sonication did not significantly affect water repellence. By this fabrication method the size of the wrinkles can be reproducibly tuned from the nanoscale to the microscale, across the whole surface in one step; the fabrication procedure is extremely rapid, requiring only 2 min of thermal annealing to produce the desired topography, and uses inexpensive materials. The very low roll-off angles achieved in the hierarchical surfaces offer a potentially up-scalable alternative as self-cleaning and drag-reducing coatings. PMID:26910574

  7. Genomic functions of U2AF in constitutive and regulated splicing

    PubMed Central

    Wu, Tongbin; Fu, Xiang-Dong

    2015-01-01

    The U2AF heterodimer is generally accepted to play a vital role in defining functional 3′ splice sites in pre-mRNA splicing. Given prevalent mutations in U2AF, particularly in the U2AF1 gene (which encodes for the U2AF35 subunit) in blood disorders and other human cancers, there are renewed interests in these classic splicing factors to further understand their regulatory functions in RNA metabolism in both physiological and disease settings. We recently reported that U2AF has a maximal capacity to directly bind ˜88% of functional 3′ splice sites in the human genome and that numerous U2AF binding events also occur in various exonic and intronic locations, thus providing additional mechanisms for the regulation of alternative splicing besides their traditional role in titrating weak splice sites in the cell. These findings, coupled with the existence of multiple related proteins to both U2AF65 and U2AF35, beg a series of questions on the universal role of U2AF in functional 3′ splice site definition, their binding specificities in vivo, potential mechanisms to bypass their requirement for certain intron removal events, contribution of splicing-independent functions of U2AF to important cellular functions, and the mechanism for U2AF mutations to invoke specific diseases in humans. PMID:25901584

  8. Magnetic and EXAFS Characterization of Inverted Zinc Ferrite Powders

    NASA Astrophysics Data System (ADS)

    Oliver, S. A.; Harris, V. G.; Hamdeh, H. H.; Ho, J. C.; Willey, R. J.

    1996-03-01

    Zinc ferrite is typically considered to be a normal spinel, with zinc cations exclusively occupying the tetrahedral (A) sites, and the iron cations on the octahedral (B) sites. Then zinc ferrite is an antiferromagnet with a Neel temperature near 10 K. We have found that fine (10 nm) zinc ferrite powders produced by the supercritical sol-gel (aerogel) process have a substantial site inversion parameter of 0.20. These powders show indications from Mossbauer effect measurements for magnetic ordering to temperatures above 200 K, along with strong superparamagnetic effects. As expected, calcining these powders lowers the measured Curie temperature. However, ball-milling the powders yields samples with substantial magnetizations at room temperature. We have used EXAFS to confirm the large inversion parameter for the ball-milled powders, and will report on Mossbauer effect, magnetization, and calorimetric measurements taken on these powders.

  9. Recovery of Manganese Ferrite in Nanoform from the Metallurgical Slags

    NASA Astrophysics Data System (ADS)

    Semykina, Anna; Seetharaman, Seshadri

    2011-02-01

    The present work investigates the formation of manganese ferrite of nanosize by oxidation of MnO- and FeO-containing slag. A horizontal resistance furnace was used as an experimental setup. The experiment was conducted in the temperature range of 1573 K to 1673 K (1300 °C to 1400 °C) in an oxidizing atmosphere. The samples were quenched to the cold end of the furnace and were analyzed by X-ray diffraction (XRD). The XRD patterns of the products showed the presence of two phases—manganese ferrite and calcium silicate. The particle size of the manganese ferrite was estimated by the Scherrer formula to be in the range of nanometers.

  10. Mixed-phase bismuth ferrite nanoflake electrodes for supercapacitor application

    NASA Astrophysics Data System (ADS)

    Jadhav, Vijaykumar V.; Zate, Manohar K.; Liu, Shude; Naushad, Mu.; Mane, Rajaram S.; Hui, K. N.; Han, Sung-Hwan

    2016-04-01

    Nanoflake bismuth ferrite thin film was synthesized by means of electrodeposition technique at room temperature. The morphology and phase evaluation of the synthesized electrode were analyzed using scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and surface wettability techniques. Specifically, the bismuth ferrite nanoflake electrode exhibited high specific capacitance of 72.2 F g-1 at a current density of 1 A g-1, and high rate capability with 37 % retention of capacitance even up to 20A g-1, and excellent cycling stability with 82.8 % retention of the initial capacitance after 1500 charge/discharge cycles, supporting that the bismuth ferrite thin-film electrode could be a potential candidate for supercapacitor application.

  11. Study on the mechanism of ferrite-induced dinitrophenol photodegradation.

    PubMed

    Zaharia, Marius; Borhan, Adrian; Gherca, Daniel; Pui, Aurel; Gradinaru, Robert; Zbancioc, Gheorghita; Drochioiu, Gabi

    2014-01-01

    We report here the effectiveness of gas chromatography mass spectrometry techniques in establishing the ferrite-associated photocatalytic degradation mechanism of pesticide 2,4-dinitrophenol (2,6-DNP). Unlike the previously discussed DNP-degradation mechanisms that involve either oxidation or reduction reactions, ferrite-based ultraviolet (UV) photodegradation of DNP affords the nontoxic 6-hydroxy-3,5-dinitrohexa-2,4-dienal by an unusual water addition to the benzene core. We searched for and demonstrated the presence of an epoxide of DNP within the photodegradation process, which may unambiguously explain the novel photochemical mechanism. During the 15 min UV photoinduced process, DNP degradation efficiency on the zinc ferrite catalyst was calculated to be 82%, whereas the first-order kinetic rate constant k was as high as 3.4 x 10(-2)min(-1). PMID:24895780

  12. Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications.

    PubMed

    Sanpo, Noppakun; Berndt, Christopher C; Wen, Cuie; Wang, James

    2013-03-01

    Transition metals of copper, zinc, chromium and nickel were substituted into cobalt ferrite nanoparticles via a sol-gel route using citric acid as a chelating agent. The microstructure and elemental composition were characterized using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. Phase analysis of transition metal-substituted cobalt ferrite nanoparticles was performed via X-ray diffraction. Surface wettability was measured using the water contact angle technique. The surface roughness of all nanoparticles was measured using profilometry. Moreover, thermogravimetric analysis and differential scanning calorimetry were performed to determine the temperature at which the decomposition and oxidation of the chelating agents took place. Results indicated that the substitution of transition metals influences strongly the microstructure, crystal structure and antibacterial property of the cobalt ferrite nanoparticles. PMID:23137676

  13. Ferrite core non-linearity in coils for magnetic neurostimulation

    PubMed Central

    Lazzi, Gianluca

    2014-01-01

    The need to correctly predict the voltage across terminals of mm-sized coils, with ferrite core, to be employed for magnetic stimulation of the peripheral neural system is the motivation for this work. In such applications, which rely on a capacitive discharge on the coil to realise a transient voltage curve of duration and strength suitable for neural stimulation, the correct modelling of the non-linearity of the ferrite core is critical. A demonstration of how a finite-difference model of the considered coils, which include a model of the current-controlled inductance in the coil, can be used to correctly predict the time-domain voltage waveforms across the terminals of a test coil is presented. Five coils of different dimensions, loaded with ferrite cores, have been fabricated and tested: the measured magnitude and width of the induced pulse are within 10% of simulated values. PMID:26609390

  14. Nanosized copper ferrite materials: Mechanochemical synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Manova, Elina; Tsoncheva, Tanya; Paneva, Daniela; Popova, Margarita; Velinov, Nikolay; Kunev, Boris; Tenchev, Krassimir; Mitov, Ivan

    2011-05-01

    Nanodimensional powders of cubic copper ferrite are synthesized by two-steps procedure of co-precipitation of copper and iron hydroxide carbonates, followed by mechanochemical treatment. X-ray powder diffraction, Mössbauer spectroscopy and temperature-programmed reduction are used for the characterization of the obtained materials. Their catalytic behavior is tested in methanol decomposition to hydrogen and CO and total oxidation of toluene. Formation of nanosized ferrite material is registered even after one hour of milling time. It is established that the prolonging of treatment procedure decreases the dispersion of the obtained product with the appearance of Fe 2O 3. It is demonstrated that the catalytic behavior of the samples depends not only on their initial phase composition, but on the concomitant ferrite phase transformations by the influence of the reaction medium.

  15. Comparison of conventional and microwave sintering on Y-ferrite

    NASA Astrophysics Data System (ADS)

    Obulesu, K. Rama; James Raju, K. C.

    2013-06-01

    In this paper we are comparing the results of the conventional and microwave sintered samples of Zn2-Y(Ba2Zn2Fe12O22) ferrite. Y ferrite sample was synthesized using the commercial solid-state reaction method. In CS process, the sample was sintered in muffle furnace at 1200°C for 6 h. In MS process, the sample was sintered at 1120 °C for 30 min in air at the rate of 10°C per min. X-ray powder diffraction revealed that a single phase rhombohedral structure with space group R3m (166) for both samples. The average grain size of CS sample is 1.5-2μm which is greater than MS sample. Magnetic properties also changed with the microwave sintering. These results demonstrate that the strong microwave method is an alternative way to synthesize high performance Y ferrite.

  16. Identification and functional characterization of grass carp IL-17A/F1: An evaluation of the immunoregulatory role of teleost IL-17A/F1.

    PubMed

    Du, Linyong; Feng, Shiyu; Yin, Licheng; Wang, Xinyan; Zhang, Anying; Yang, Kun; Zhou, Hong

    2015-07-01

    In mammals, IL-17A and IL-17F are hallmark cytokines of Th17 cells which act significant roles in eradicating extracellular pathogens. IL-17A and IL-17F homologs nominated as IL-17A/F1-3 have been revealed in fish and their functions remain largely undefined. Here we identified and characterized grass carp IL-17A/F1 (gcIL-17A/F1) in fish immune system. In this regard, both tissue distribution and inductive expression of gcIL-17A/F1 indicated its possible involvement in immune response. Moreover, recombinant gcIL-17A/F1 (rgcIL-17A/F1) was prepared and displayed an ability to enhance pro-inflammatory cytokines (IL-1β, TNF-α and IL-6) mRNA expression in head kidney leukocytes. It is suggestive of that gcIL-17A/F1 may act as a proinflammatory cytokine in fish immunity. Besides, rgcIL-17A/F1 induced gene expression and protein release of grass carp chemokine CXCL-8 (gcCXCL-8) in head kidney cells (HKCs), probably via NF-κB, p38 and Erk1/2 pathways. In particular, culture medium from the HKCs treated by rgcIL-17A/F1 could stimulate peripheral blood leukocytes migration and immunoneutralization of endogenous gcCXCL-8 could partially attenuate this stimulation, suggesting that rgcIL-17A/F1 could recruit immune cells through producing gcCXCL-8 as mammalian IL-17 A and F. Taken together, we not only identified the pro-inflammatory role of gcIL-17A/F1 in host defense, but also provided the basis for clarifying Th17 cells in teleost. PMID:25847875

  17. XANES evidence of arsenate removal from water with magnetic ferrite.

    PubMed

    Tu, Yao-Jen; You, Chen-Feng; Chang, Chien-Kuei; Wang, Shan-Li

    2013-05-15

    Arsenic (As) in groundwater and surface water is a worldwide problem possessing a serious threat to public health. In this study, a magnetic ferrite, was synthesized and investigated for its As(V) removal efficiency. The adsorption of As(V) by magnetic ferrite exhibited an L-shaped nonlinear isotherm, suggesting limiting binding sites on the adsorbent surface. The As K-edge X-Ray Absorption Near-Edge Structure (XANES) revealed that the adsorbed As(V) on ferrite was not reduced to more toxic As(III) by Fe(2+) in the ferrite structure. The maximum As adsorption capacity of ferrite was 14 mg/g at pH 3 and decreased with increasing pH due to enhanced electrostatic repulsion between As(V) and the adsorbent surface. Desorption of As(V) using six different acid and salt solutions showed that the desorption rate decreased in an order of H3PO4 > Na3PO4 > H2SO4 > Na2SO4 > HCl > HNO3. These results suggest that magnetic ferrite without surface modification is an effective adsorbent for removing As(V) from water, which was confirmed by the effective removal of As(V) from contaminated groundwater using this material. The used material can then be recovered using a magnet because of its paramagnetism; the adsorbed As(V) on the material can be recovered using H3PO4 or Na3PO4 solutions. PMID:23507250

  18. Gas atomization of cobalt ferrite-phosphate melts

    NASA Technical Reports Server (NTRS)

    De Guire, Mark R.; O'Handley, R. C.; Kalonji, G.

    1989-01-01

    XRD, Moessbauer spectroscopy, and EDXS have been used to characterize a rapidly-solidified (Co,Fe)3O4 spinel generated in a cobalt-iron-phosphate glass matrix by gas atomization of melts. Of the two compositions tested, that containing 20 mol pct P2O5 exhibited randomly-oriented ferrite crystallization whose growth appears to have been diffusion-controlled. Unlike the ferrite, in which the iron has both tetrahedral and octahedral coordination, the iron in the glassy matrix was primarily of distorted-octahedral coordination. Calculations indicate that the cooling rates obtained with oxide melts vary strongly with droplet size, but less strongly with melt temperature.

  19. Microstructural examination of commercial ferritic alloys at 200 dpa

    NASA Astrophysics Data System (ADS)

    Gelles, D. S.

    1996-10-01

    Microstructures and density change measurements are reported for martensitic commercial steels HT-9 and modified 9Cr1Mo (T91) and oxide dispersion strengthened ferritic alloys MA956 and MA957 following irradiation in the FFTF/MOTA at 420°C to 200 dpa. Swelling as determined by density change remains below 2% for all conditions. Microstructures are found to be stable except in recrystallized grains of MA957, which are fabrication artifacts, with only minor swelling in the martensitic steels and α' precipitation in alloys with 12% or more chromium. These results further demonstrate the high swelling resistance and microstructural stability of the ferritic alloy class.

  20. Microstructure and texture of Nb + Ti stabilized ferritic stainless steel

    SciTech Connect

    Yan Haitao Bi Hongyun; Li Xin; Xu Zhou

    2008-12-15

    The microstructure, texture and grain boundary character distribution of Nb + Ti stabilized ferritic stainless steel were analyzed using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The addition of alloying elements such as Ti and Nb to ferritic stainless steel causes the formation of TiN, NbC and Fe{sub 2}Nb. The textures of cold rolled samples were dominated by the {alpha}-fiber, while the textures of annealed samples exhibit a very strong {gamma}-fiber. The changes in texture are closely related to the grain boundary characteristics.

  1. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1988-11-14

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  2. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1989-05-02

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  3. ON QUANTIFICATION OF HELIUM EMBRITTLEMENT IN FERRITIC/MARTENSITIC STEELS

    SciTech Connect

    Gelles, David S.

    2000-12-01

    Helium accumulation due to transmutation has long been considered a potential cause for embrittlement in ferritic/martensitic steels. Three Charpy impact databases involving nickel- and boron-doped alloys are quantified with respect to helium accumulation, and it is shown that all predict a very large effect of helium production on embrittlement. If these predictions are valid, use of Ferritic/Martensitic steels for Fusion first wall applications is highly unlikely. It is therefore necessary to reorient efforts regarding development of these steels for fusion applications to concentrate on the issue of helium embrittlement.

  4. Fabrication of oxide dispersion strengthened ferritic clad fuel pins

    SciTech Connect

    Zirker, L.R. ); Bottcher, J.H. ); Shikakura, S. ); Tsai, C.L. . Dept. of Welding Engineering); Hamilton, M.L. )

    1991-01-01

    A resistance butt welding procedure was developed and qualified for joining ferritic fuel pin cladding to end caps. The cladding are INCO MA957 and PNC ODS lots 63DSA and 1DK1, ferritic stainless steels strengthened by oxide dispersion, while the end caps are HT9 a martensitic stainless steel. With adequate parameter control the weld is formed without a residual melt phase and its strength approaches that of the cladding. This welding process required a new design for fuel pin end cap and weld joint. Summaries of the development, characterization, and fabrication processes are given for these fuel pins. 13 refs., 6 figs., 1 tab.

  5. Achieving process control through improved grinding techniques for ferrite materials

    SciTech Connect

    Bruce, J.

    1995-09-01

    In manufacturing soft ferrite materials the particle size of the raw material has a significant impact on the reactivity of calcination. The control of particle size distribution and final formulation at wet milling after calcining impacts the reactivity during sintering and the magnetic properties of the final product. This paper will deal with steps taken to improve process control during the grinding operations of raw material and calcine in soft ferrite production. Equipment modifications as well as changes to the grinding and material handling techniques will be included. All examples of process control and improvements will be supported by data.

  6. Structural and magnetic study of dysprosium substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kumar, Hemaunt; Srivastava, R. C.; Pal Singh, Jitendra; Negi, P.; Agrawal, H. M.; Das, D.; Hwa Chae, Keun

    2016-03-01

    The present work investigates the magnetic behavior of Dy3+ substituted cobalt ferrite nanoparticles. X-ray diffraction studies reveal presence of cubic spinel phases in these nanoparticles. Raman spectra of these nanoparticles show change in intensity of Raman bands, which reflects cation redistribution in cubic spinel lattice. Saturation magnetization and coercivity decrease with increase of Dy3+concentration in these nanoparticles. Room temperature Mössbauer measurements show the cation redistribution in these nanoparticles and corroborates the results obtained from Raman Spectroscopic measurements. Decrease in magnetization of Dy3+ substituted cobalt ferrite is attributed to the reduction in the magnetic interaction and cation redistribution.

  7. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect

    Mukherjee, A. Banerjee, M. Basu, S.; Pal, M.

    2014-04-24

    Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

  8. Control of magnetization reversal in oriented strontium ferrite thin films

    SciTech Connect

    Roy, Debangsu Anil Kumar, P. S.

    2014-02-21

    Oriented Strontium Ferrite films with the c axis orientation were deposited with varying oxygen partial pressure on Al{sub 2}O{sub 3}(0001) substrate using Pulsed Laser Deposition technique. The angle dependent magnetic hysteresis, remanent coercivity, and temperature dependent coercivity had been employed to understand the magnetization reversal of these films. It was found that the Strontium Ferrite thin film grown at lower (higher) oxygen partial pressure shows Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of pinning and nucleation processes during magnetization reversal is used to explain the type of the magnetization reversal with different oxygen partial pressure during growth.

  9. The role of cobalt ferrite magnetic nanoparticles in medical science.

    PubMed

    Amiri, S; Shokrollahi, H

    2013-01-01

    The nanotechnology industry is rapidly growing and promises that the substantial changes that will have significant economic and scientific impacts be applicable to a wide range of areas, such as aerospace engineering, nano-electronics, environmental remediation and medical healthcare. In this area, cobalt ferrite nanoparticles have been regarded as one of the competitive candidates because of their suitable physical, chemical and magnetic properties like the high anisotropy constant, high coercivity and high Curie temperature, moderate saturation magnetization and ease of synthesis. This paper introduces the magnetic properties, synthesis methods and some medical applications, including the hyperthermia, magnetic resonance imaging (MRI), magnetic separation and drug delivery of cobalt ferrite nanoparticles. PMID:25428034

  10. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1988-08-19

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  11. Influence of Nanocrystalline Ferrite Particles on Properties of Magnetic Systems

    NASA Astrophysics Data System (ADS)

    Mueller, Robert; Habisreuther, Tobias; Hiergeist, Robert; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    Nanocrystalline mainly superparamagnetic ferrite particles ≈ 10 nm are used for the preparation of magnetic fluids. Barium hexaferrite BaFe12-2xTixCoxO19 powders with mean particle sizes < 30 nm show the transition to single domain Stoner-Wohlfarth behaviour. Hysteresis parameters, losses and the initial susceptibility versus temperature were obtained by VSM. Ba-ferrite ferrofluids have been prepared using Isopar M or dodecane as carrier liquid. Small Angle Neutron Scattering curves lead to a bimodal size distribution consisting of single magnetic particles and aggregated magnetic particles. Particle size investigations were done by TEM.

  12. Connection between micro and macro hardness pearlitic-ferritic steel

    NASA Astrophysics Data System (ADS)

    Duka, Edlira; Oettel, Heinrich; Dilo, Teuta

    2012-09-01

    Many physical and mechanical properties of materials are closely related to their microstructure, technologies to control the microstructure of materials have been well developed to obtain suitable properties. We measured the volume fraction of perlite and ferrite, micro Vickers hardness in pearlite and ferrite and macro hardness using different sample with different carbon content. The volume fraction of pearlite increases by increasing carbon content. By increasing carbon content, micro and macro hardness increase. We can conclude that for those conditional the mixing rule can't be use.

  13. Corrosion performance of laser-welded austenitic-ferritic connections

    NASA Astrophysics Data System (ADS)

    Weigl, M.; Schmidt, M.

    2013-02-01

    In order to reduce the material costs of white-goods made of stainless steels, tailored constructions with unequally alloyed stainless steels shall be used. For that purpose nickel-alloyed austenitic stainless steels are supposed to be limited to zones with demanding needs for corrosions resistance, whereas nickel-free ferritic stainless steels provide an attractive cost-performance ratio for the remaining components of a system. Particularly the present article discusses the corrosion performance of austenitic-ferritic connections, welded with high-power disc lasers at accelerated feed rates, as a function of the shielding gas composition and the surface condition.

  14. The filler powders laser welding of ODS ferritic steels

    NASA Astrophysics Data System (ADS)

    Liang, Shenyong; Lei, Yucheng; Zhu, Qiang

    2015-01-01

    Laser welding was performed on Oxide Dispersion Strengthened (ODS) ferritic steel with the self-designed filler powders. The filler powders were added to weld metal to produce nano-particles (Y-M-O and TiC), submicron particles (Y-M-O) and dislocation rings. The generated particles were evenly distributed in the weld metal and their forming mechanism and behavior were analyzed. The results of the tests showed that the nano-particles, submicron particles and dislocation rings were able to improve the micro-hardness and tensile strength of welded joint, and the filler powders laser welding was an effective welding method of ODS ferritic steel.

  15. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Jha, M.C.; Berggren, M.H.

    1989-03-06

    AMAX Research Development Center (AMAX R D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  16. Microstructural Characterization and Mechanical Properties Analysis of Weld Metals with Two Ni Contents During Post-Weld Heat Treatments

    NASA Astrophysics Data System (ADS)

    Wu, Da-yong; Han, Xiu-lin; Tian, Hong-tao; Liao, Bo; Xiao, Fu-ren

    2015-05-01

    This study designed post-weld heat treatments, including reheating and tempering, associated with hot bending to investigate the microstructures, toughness, and hardness of two weld metals with different Ni contents (<1 wt pct level). The results indicated that a high Ni content decreased the ferrite transformation temperature and increased the proportion of acicular ferrite (AF). Furthermore, a high Ni content promoted the martensite/austenite (M/A) constituent formation after reheating. The promotion of the M/A formation increased the number of cementite particles, and accelerated cementite coarsening during tempering. The large-angle grain boundary density from the AF improved the toughness despite the negative effect of cementite. The strengthening contributions were calculated, and the grain refinement was the greatest. The high Ni content decreased the effective grain size with a 2 deg tolerance angle, thus enhancing the grain refinement contribution.

  17. Cobalt ferrite based magnetostrictive materials for magnetic stress sensor and actuator applications

    NASA Technical Reports Server (NTRS)

    Jiles, David C. (Inventor); Paulsen, Jason A. (Inventor); Snyder, John E. (Inventor); Lo, Chester C. H. (Inventor); Ring, Andrew P. (Inventor); Bormann, Keith A. (Inventor)

    2008-01-01

    Magnetostrictive material based on cobalt ferrite is described. The cobalt ferrite is substituted with transition metals (such manganese (Mn), chromium (Cr), zinc (Zn) and copper (Cu) or mixtures thereof) by substituting the transition metals for iron or cobalt to form substituted cobalt ferrite that provides mechanical properties that make the substituted cobalt ferrite material effective for use as sensors and actuators. The substitution of transition metals lowers the Curie temperature of the material (as compared to cobalt ferrite) while maintaining a suitable magnetostriction for stress sensing applications.

  18. Influence of initial particle size on the magnetostriction of sintered cobalt ferrite derived from nanocrystalline powders

    NASA Astrophysics Data System (ADS)

    Khaja Mohaideen, K.; Joy, P. A.

    2013-11-01

    The role of initial particle size on the magnetostriction coefficient of sintered cobalt ferrite derived from nanocrystalline powders is studied. Nanoparticles of cobalt ferrite with different sizes in the range 3-80 nm are synthesized by an autocombustion method using metal nitrates and glycine. It has been observed that the initial particle size of the starting powders has a strong influence on the magnetostrictive behavior of sintered cobalt ferrite. Highest magnetostrictive strain and strain derivative are obtained for sintered ferrite derived from nanoparticles of size < 5 nm. The results show that higher magnetostriction coefficient for sintered cobalt ferrite can be achieved by compacting nanocrystalline particles of very small size.

  19. Microwave absorption property of plasma spray W-type hexagonal ferrite coating

    NASA Astrophysics Data System (ADS)

    Wei, Shicheng; Liu, Yi; Tian, Haoliang; Tong, Hui; Liu, Yuxin; Xu, Binshi

    2015-03-01

    In order to enhance the adhesion strength of microwave absorbing materials, W-type hexagonal ferrite coating is fabricated by plasma spray. The feedstock of ferrite powders is synthesized by solid-state reaction and spray dried process. Microstructures of the coating are analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectra (EDS). Hexagonal ferrite coating is successfully deposited on the substrate with adhesion strength of 28 MPa. The magnetic property of ferrite samples is measured using vibrating sample magnetometer (VSM). Saturation magnetization of the ferrite coating is lower than ferrite powder. Reflection loss of the hexagonal ferrite coating is measured in frequency of 2-18 GHz. The result shows that the coating is suitable for electromagnetic wave absorbers in Ku-band.

  20. Binding sites for two novel phosphoproteins, 3AF5 and 3AF3, are required for rbcS-3A expression.

    PubMed Central

    Sarokin, L P; Chua, N H

    1992-01-01

    Previous studies of boxes II (-151 to -138) and III (-125 to -114), binding sites for the nuclear factor GT-1 within the -166 deleted promoter of the ribulose-1,5-bisphosphate carboxylase-3A (rbcS-3A) gene, suggested that GT-1 might act in concert with an additional protein to confer light-responsive rbcS-3A expression. In this work, S1 analysis of RNA isolated from transgenic tobacco plants carrying mutant rbcS-3A constructs led to the identification of two short sequences located at the 5' and 3' ends of box III that are required for expression. These two sequences serve as binding sites for two novel proteins, 3AF5 and 3AF3. Gel shift studies using tetramerized binding sites for both 3AF5 and 3AF3 showed that complexes with faster mobilities were formed using nuclear extracts prepared from dark-adapted plants compared with those from light-grown tobacco plants. Phosphatase treatment of extracts from light-grown plants resulted in the formation of complexes with faster mobility. Although the binding of 3AF3 to its target site is dependent upon phosphorylation, the binding of 3AF5 does not appear to be affected by its phosphorylation state. These results suggest that the phosphorylated forms of both 3AF5 and 3AF3 are required for -166 rbcS-3A expression but that the mechanisms differ by which phosphorylation regulates the activities of 3AF5 and 3AF3. PMID:1498605

  1. Ferritic Fe-Mn alloy for cryogenic applications

    DOEpatents

    Hwang, Sun-Keun; Morris, Jr., John W.

    1979-01-01

    A ferritic, nickel-free alloy steel composition, suitable for cryogenic applications, which consists essentially of about 10-13% manganese, 0.002-0.01% boron, 0.1-0.5% titanium, 0-0.05% aluminum, and the remainder iron and incidental impurities normally associated therewith.

  2. Austenite to ferrite transformation kinetics during continuous cooling

    SciTech Connect

    Militzer, M.; Pandi, R.; Hawbolt, E.B.

    1994-12-31

    The austenite decomposition has been investigated in a hypo-eutectoid plain carbon steel under continuous cooling conditions using a dilatometer and a Gleeble 1500 thermomechanical simulator. The experimental results were used to verify model calculations based on a fundamental approach for the dilute ternary systems Fe-C-Mn. The austenite to ferrite transformation start temperature can be predicted from a nucleation model for slow cooling rates. The formation of ferrite nuclei takes place with equilibrium composition on austenite grain boundaries. The nuclei are assumed to have a pill box shape in accordance with minimal interfacial energy. For higher cooling rates, early growth has to be taken into account to describe the transformation start. In contrast to nucleation, growth of the ferrite is characterized by paraequilibrium; i.e. only carbon can redistribute, whereas the diffusion of Mn is too slow to allow full equilibrium in the ternary system. However, Mn segregation to the moving ferrite-austenite interface has to be considered. The latter, in turn, exerts a solute drag effect on the boundary movement. Thus, growth kinetics is controlled by carbon diffusion in austenite modified by interfacial segregation of Mn. Employing a phenomenological segregation model, good agreement has been achieved with the measurements.

  3. Mechanistic investigation of the sonochemical synthesis of zinc ferrite.

    PubMed

    Choudhury, Hanif A; Choudhary, Amit; Sivakumar, Manickam; Moholkar, Vijayanand S

    2013-01-01

    In this investigation, an attempt has been made to establish the physical mechanism of sonochemical synthesis of zinc ferrite with concurrent analysis of experimental results and simulations of cavitation bubble dynamics. Experiments have been conducted with mechanical stirring as well as under ultrasound irradiation with variation of pH and the static pressure of the reaction medium. Results of this study reveal that physical effects produced by transient cavitation bubbles play a crucial role in the chemical synthesis. Generation of high amplitude shock waves by transient cavitation bubbles manifest their effect through in situ micro-calcination of metal oxide particles (which are generated through thermal hydrolysis of metal acetates) due to energetic collisions between them. Micro-calcination of oxide particles can also occur in the thin liquid shell surrounding bubble interface, which gets heated up during transient collapse of bubbles. The sonochemical effect of production of OH radicals and H(2)O(2), in itself, is not able to yield ferrite. Moreover, as the in situ micro-calcination involves very small number of particles or even individual particles (as in intra-particle collisions), the agglomeration between resulting ferrite particles is negligible (as compared to external calcination in convention route), leading to ferrite particles of smaller size (6 nm). PMID:22805260

  4. Magnetic properties of bio-synthesized zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Yeary, Lucas W.; Moon, Ji-Won; Rawn, Claudia J.; Love, Lonnie J.; Rondinone, Adam J.; Thompson, James R.; Chakoumakos, Bryan C.; Phelps, Tommy J.

    2011-12-01

    The magnetic properties of zinc ferrite (Zn-substituted magnetite, ZnyFe1-yFe2O4) formed by a microbial process compared favorably with chemically synthesized materials. A metal reducing bacterium, Thermoanaerobacter, strain TOR-39 was incubated with ZnxFe1-xOOH (x=0.01, 0.1, and 0.15) precursors and produced nanoparticulate zinc ferrites. Composition and crystalline structure of the resulting zinc ferrites were verified using X-ray fluorescence, X-ray diffraction, transmission electron microscopy, and neutron diffraction. The average composition from triplicates gave a value for y of 0.02, 0.23, and 0.30 with the greatest standard deviation of 0.02. Average crystallite sizes were determined to be 67, 49, and 25 nm, respectively. While crystallite size decreased with more Zn substitution, the lattice parameter and the unit cell volume showed a gradual increase in agreement with previous literature values. The magnetic properties were characterized using a superconducting quantum interference device magnetometer and were compared with values for the saturation magnetization (Ms) reported in the literature. The averaged Ms values for the triplicates with the largest amount of zinc (y=0.30) gave values of 100.1, 96.5, and 69.7 emu/g at temperatures of 5, 80, and 300 K, respectively indicating increased magnetic properties of the bacterially synthesized zinc ferrites.

  5. Study of DNA interaction with cobalt ferrite nanoparticles.

    PubMed

    Pershina, A G; Sazonov, A E; Novikov, D V; Knyazev, A S; Izaak, T I; Itin, V I; Naiden, E P; Magaeva, A A; Terechova, O G

    2011-03-01

    Interaction of cobalt ferrite nanopowder and nucleic acid was investigated. Superparamagnetic cobalt ferrite nanoparticles (6-12 nm) were prepared by mechanochemical synthesis. Structure of the nanopowder was characterized using X-ray diffraction. It was shown that cobalt ferrite nanoparticles were associated with ssDNA and dsDNA in Tris-buffer resulting in bionanocomposite formation with mass weight relation nanoparticles: DNA 1:(0.083 +/- 0.003) and 1:(0.075 +/- 0.003) respectively. The mechanism of interaction between a DNA and cobalt ferrite nanoparticles was considered basing on the whole set of obtained data: FTIR-spectroscopy, analyzing desorption of DNA from the surface of the particles while changing the chemical content of the medium, and on the modeling interaction of specific biomolecule fragments with surface of a inorganic material. It was supposed that the linkage was based on coordination interaction of the phosphate groups and oxygen atoms heterocyclic bases of DNA with metal ions on the particle surface. These data can be used to design specific magnetic DNA-nanoparticles hybrid structures. PMID:21449452

  6. Effect of rare earth substitution in cobalt ferrite bulk materials

    NASA Astrophysics Data System (ADS)

    Bulai, G.; Diamandescu, L.; Dumitru, I.; Gurlui, S.; Feder, M.; Caltun, O. F.

    2015-09-01

    The study was focused on the influence of small amounts of rare earth (RE=La, Ce, Sm, Gd, Dy, Ho, Er, Yb) addition on the microstructure, phase content and magnetic properties of cobalt ferrite bulk materials. The X-Ray diffraction measurements confirmed the formation of the spinel structure but also the presence of secondary phases of RE oxides or orthoferrite in small percentages (up to 3%). Density measurements obtained by Archimedes method revealed a ~1 g cm-3 decrease for the RE doped cobalt ferrite samples compared with stoichiometric one. Both the Mössbauer and Fourier Transform Infrared Spectrocopy analysis results confirmed the formation of the spinel phase. The saturation magnetization and coercive field values of the doped samples obtained by Vibrating Sample Magnetometry were close to those of the pure cobalt ferrite. For magnetostrictive property studies the samples were analyzed using the strain gauge method. Higher maximum magnetostriction coefficients were found for the Ho, Ce, Sm and Yb doped cobalt ferrite bulk materials as related to the stoichiometric CoFe2O4 sample. Moreover, improved strain derivative was observed for these samples but at higher magnetic fields due to the low increase of the coercive field values for doped samples.

  7. Tuning of magnetic properties in cobalt ferrite nanocrystals

    SciTech Connect

    Cedeno-Mattei, Y.; Roman, F.; Perales-Perez, O.; Tomar, M. S.; Voyles, P. M.; Stratton, W. G.

    2008-04-01

    Cobalt ferrite (CoFe{sub 2}O{sub 4}) possesses excellent chemical stability, good mechanical hardness, and a large positive first order crystalline anisotropy constant, making it a promising candidate for magneto-optical recording media. In addition to precise control of the composition and structure of CoFe{sub 2}O{sub 4}, its practical application will require the capability to control particle size at the nanoscale. The results of a synthesis approach in which size control is achieved by modifying the oversaturation conditions during ferrite formation in water through a modified coprecipitation approach are reported. X-ray diffraction, transmission electron microscopy (TEM) diffraction, and TEM energy-dispersive x-ray spectroscopy analyses confirmed the formation of the nanoscale cobalt ferrite. M-H measurements verified the strong influence of synthesis conditions on crystal size and hence, on the magnetic properties of ferrite nanocrystals. The room-temperature coercivity values increased from 460 up to 4626 Oe under optimum synthesis conditions determined from a 2{sup 3} factorial design.

  8. Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Hernández-Gómez, P.; Muñoz, J. M.; Valente, M. A.; Torres, C.; de Francisco, C.

    2013-01-01

    Nickel ferrite nanoparticles were prepared by a modified sol-gel technique employing coconut oil, and then annealed at different temperatures in 400-1200 °C range. This route of preparation has revealed to be one efficient and cheap technique to obtain high quality nickel ferrite nanosized powder. Sample particles sizes obtained with XRD data and Scherrer's formula lie in 13 nm to 138 nm, with increased size with annealing temperature. Hysteresis loops have been obtained at room temperature with an inductive method. Magnetic field induced microwave absorption in nanoscale ferrites is a recent an active area of research, in order to characterize and explore potential novel applications. In the present work microwave magnetoabsorption data of the annealed nickel ferrite nanoparticles are presented. These data have been obtained with a system based on a network analyzer that operates in the frequency range 0 - 8.5 GHz. At fields up to 400 mT we can observe a peak according to ferromagnetic resonance theory. Sample annealed at higher temperature exhibits different absorption, coercivity and saturation magnetization figures, revealing its multidomain character.

  9. Dielectric behavior of Cu—Zn ferrites with Si additive

    NASA Astrophysics Data System (ADS)

    Uzma, G.

    2014-05-01

    Since ferrites are highly sensitive to the additives present in or added to them, extensive work, to improve the properties of basic ferrites, has been carried out on these aspects. The present paper reports the effects of composition, frequency, and temperature on the dielectric behavior of a series of CuxZn1—xFe2O4 ferrite samples prepared by the usual ceramic technique. In order to improve the properties of the samples, low cost Fe2O3 having 0.5 wt.% Si as an additive is selected to introduce into the system. The dielectric constant increases by increasing the Cu content, as the electron exchange of Cu2+ <=> Cu+ is responsible for the conduction and the polarization. However, the addition of Si could decrease the dielectric constant as it suppresses the ceramic grain growth and promotes the quality factor at higher frequencies. Dielectric constant ɛ' and loss tangent tan δ of the mixed Cu—Zn ferrite decrease with increasing frequency, attributed to the Maxwell—Wagner polarization, which increases as the temperature increases.

  10. Deuterium Retention and Physical Sputtering of Low Activation Ferritic Steel

    NASA Astrophysics Data System (ADS)

    T, Hino; K, Yamaguchi; Y, Yamauchi; Y, Hirohata; K, Tsuzuki; Y, Kusama

    2005-04-01

    Low activation materials have to be developed toward fusion demonstration reactors. Ferritic steel, vanadium alloy and SiC/SiC composite are candidate materials of the first wall, vacuum vessel and blanket components, respectively. Although changes of mechanical-thermal properties owing to neutron irradiation have been investigated so far, there is little data for the plasma material interactions, such as fuel hydrogen retention and erosion. In the present study, deuterium retention and physical sputtering of low activation ferritic steel, F82H, were investigated by using deuterium ion irradiation apparatus. After a ferritic steel sample was irradiated by 1.7 keV D+ ions, the weight loss was measured to obtain the physical sputtering yield. The sputtering yield was 0.04, comparable to that of stainless steel. In order to obtain the retained amount of deuterium, technique of thermal desorption spectroscopy (TDS) was employed to the irradiated sample. The retained deuterium desorbed at temperature ranging from 450 K to 700 K, in the forms of DHO, D2, D2O and hydrocarbons. Hence, the deuterium retained can be reduced by baking with a relatively low temperature. The fluence dependence of retained amount of deuterium was measured by changing the ion fluence. In the ferritic steel without mechanical polish, the retained amount was large even when the fluence was low. In such a case, a large amount of deuterium was trapped in the surface oxide layer containing O and C. When the fluence was large, the thickness of surface oxide layer was reduced by the ion sputtering, and then the retained amount in the oxide layer decreased. In the case of a high fluence, the retained amount of deuterium became comparable to that of ferritic steel with mechanical polish or SS 316L, and one order of magnitude smaller than that of graphite. When the ferritic steel is used, it is required to remove the surface oxide layer for reduction of fuel hydrogen retention. Ferritic steel sample was

  11. The Advancing State of AF-M315E Technology

    NASA Technical Reports Server (NTRS)

    Masse, Robert; Spores, Ronald A.; McLean, Chris

    2014-01-01

    The culmination of twenty years of applied research in hydroxyl ammonium nitrate (HAN)-based monopropellants, the NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) will achieve the first on-orbit demonstration of an operational AF-M315E green propellant propulsion system by the end of 2015. Following an contextual overview of the completed flight design of the GPIM propellant storage and feed system, results of first operation of a flight-representative heavyweight 20-N engineering model thruster (to be conducted in mid-2014) are presented with performance comparisons to prior lab model (heavyweight) test articles.

  12. RX-26-AY/AF rifle bullet tests

    SciTech Connect

    Sharp, D.D.

    1980-11-01

    A series of rifle bullet tests was performed on two explosives, RX-26-AY and RX-26-AF, using the Pantex version of the Picatinny Arsenal Test (PA-2). With the exception of one test, both explosives displayed a relatively low sensitivity to bullet impact. However, a marked difference was noted in the average burn time duration between the two types of explosives being tested. A minor modification was made on the rifle barrel used at the test site in order to improve the sighting procedure.

  13. NMR study of the AF-SC-SC-AF phased transition in a pnictide superconductor LaFeAsO1-xHx

    NASA Astrophysics Data System (ADS)

    Fujiwara, Naoki; Sakurai, Ryosuke; Iimura, Soushi; Matsuishi, Satoru; Hosono, Hideo; Yamakawa, Youichi; Kontani, Hiroshi

    2014-03-01

    We have performed 75As and 1H NMR measurements in LaFeAsO1xHx, an isomorphic compound of LaFeAsO1xFx. LaFeAsO1xHx is an electron doped system, and O2- can be replaced with H- up to x = 0.5. LaFeAsO1xHx is known for having double superconducting (SC) domes on H doping. Recently, we discovered that a new antiferromagnetic (AF) phase follows the double SC domes on further H doping, forming a symmetric AF-SC-SC-AF phase alignment in the electronic phase diagram Unlike the AF ordering in the lightly H-doped regime, the AF ordering in the highly H-doped regime is attributed to the nesting between electron pockets. In the conference, we will show the data of both NMR spectra and the relaxation rate 1/T1 in the whole doping region. We will discuss the difference of electronic states between the lightly H-doped AF-SC phases and highly H-doped SC-AF phases. This work is supported by a Grant-in-Aid (Grant No. KAKENHI 23340101) from the Ministry of Education, Science, and Culture, Japan.

  14. AFS men and women differ most in their lifestyle choices

    USGS Publications Warehouse

    Connelly, N.A.; Brown, T.L.; Hardiman, J.M.

    2006-01-01

    The American Fisheries Society sponsored a survey to examine the career development choices of men and women and how they might differ by gender. A random sample of 700 men and 700 women was selected from the AFS membership database. The survey was mailed out in October 2004 and 991 questionnaires were returned for an adjusted response rate of 71%. Some differences exist between men and women in the areas of interest development, education, and employment, but the substantive differences occur in lifestyle choices. Women with a fisheries career are less likely to be married than men, even when age is controlled for, and women who are married are more likely to have dual-career considerations than their male counterparts. Among respondents without dependents in their home during their professional career, twice as many women as men think having children will adversely affect their career. For those with dependents, more than twice as many women as men said they had to put their career "on hold" because of their dependents. While AFS members do not represent all members of the fisheries profession, their experiences shed substantial light on the lifestyle choices likely faced by most members of the profession.

  15. Identification and characterization of the afsR homologue regulatory gene from Streptomyces peucetius ATCC 27952.

    PubMed

    Parajuli, Niranjan; Viet, Hung Trinh; Ishida, Kenji; Tong, Hang Thi; Lee, Hei Chan; Liou, Kwangkyoung; Sohng, Jae Kyung

    2005-01-01

    We have isolated an afsR homologue, called afsR-p, through genome analysis of Streptomyces peucetius ATCC 27952. AfsR-p shares 60% sequence identity with AfsR from Streptomyces coelicolor A3 (2). afsR-p was expressed under the control of the ermE* promoter in its hosts S. peucetius, Streptomyces lividans TK 24, Streptomyces clavuligerus and Streptomyces griseus. We observed overproduction of doxorubicin (4-fold) in S. peucetius, gamma-actinorhodin (2.6-fold) in S. lividans, clavulanic acid (1.5-fold) in S. clavuligerus and streptomycin (slight) in S. griseus. Overproduction was due to expression of the gene in these strains as compared to the wild-type strains harboring the vector only. Comparative study of the expression of afsR-p revealed that regulatory networking in Streptomyces is not uniform. We speculate that phosphorylated AfsR-p becomes bound to the promoter region of afsS. The latter activates other regulatory genes, including pathway regulatory genes, and induces the production of secondary metabolites including antibiotics. We identified specific conserved amino acids and exploited them for the isolation of the partial sequence of the afsR homologue from S. clavuligerus and Streptomyces achromogens (rubradirin producer). Such findings provide additional evidence for the presence of a serine/threonine and tyrosine kinase-dependent global regulatory network in Streptomyces. PMID:15921897

  16. Dual Function for U2AF35 in AG-Dependent Pre-mRNA Splicing

    PubMed Central

    Guth, Sabine; Tange, Thomas O/.; Kellenberger, Esther; Valcárcel, Juan

    2001-01-01

    The splicing factor U2AF is required for the recruitment of U2 small nuclear RNP to pre-mRNAs in higher eukaryotes. The 65-kDa subunit of U2AF (U2AF65) binds to the polypyrimidine (Py) tract preceding the 3′ splice site, while the 35-kDa subunit (U2AF35) contacts the conserved AG dinucleotide at the 3′ end of the intron. It has been shown that the interaction between U2AF35 and the 3′ splice site AG can stabilize U2AF65 binding to weak Py tracts characteristic of so-called AG-dependent pre-mRNAs. U2AF35 has also been implicated in arginine-serine (RS) domain-mediated bridging interactions with splicing factors of the SR protein family bound to exonic splicing enhancers (ESE), and these interactions can also stabilize U2AF65 binding. Complementation of the splicing activity of nuclear extracts depleted of U2AF by chromatography in oligo(dT)-cellulose requires, for some pre-mRNAs, only the presence of U2AF65. In contrast, splicing of a mouse immunoglobulin M (IgM) M1-M2 pre-mRNA requires both U2AF subunits. In this report we have investigated the sequence elements (e.g., Py tract strength, 3′ splice site AG, ESE) responsible for the U2AF35 dependence of IgM. The results indicate that (i) the IgM substrate is an AG-dependent pre-mRNA, (ii) U2AF35 dependence correlates with AG dependence, and (iii) the identity of the first nucleotide of exon 2 is important for U2AF35 function. In contrast, RS domain-mediated interactions with SR proteins bound to the ESE appear to be dispensable, because the purine-rich ESE present in exon M2 is not essential for U2AF35 activity and because a truncation mutant of U2AF35 consisting only of the pseudo-RNA recognition motif domain and lacking the RS domain is active in our complementation assays. While some of the effects of U2AF35 can be explained in terms of enhanced U2AF65 binding, other activities of U2AF35 do not correlate with increased cross-linking of U2AF65 to the Py tract. Collectively, the results argue that

  17. Analysis of delta-ferrite data from production stainless steel pipe welds

    SciTech Connect

    Hebble, T.L.; Canonico, D.A.; Edmonds, D.P.; Goodwin, G.M.; Nanstad, R.K.

    1984-01-01

    An American Society of Mechanical Engineers task group on stainless steel weld materials was organized to determine the need for ferrite measurements of production welds required by the US Nuclear Regulatory Commission Regulatory Guide 1.31 (Rev. 1). The task group studied paired ferrite measurements (i.e., calculated and measured ferrite numbers (FNs) for the material qualifications versus measured ferrite numbers for corresponding production welds (PWs)). Our purpose was to compare delta-ferrite content as measured in the filler metal weld qualification pad with that in the resultant PW. Welds made predominantly by three common processes (submerged arc, shielded metal arc, and gas tungsten arc) were included in the study. Weld metals investigated included types 308, 308L, 316, and 316L stainless steel. An initial evaluation of the paired ferrite measurements was made by the task group, and specific conclusions and recommendations were made. We describe the analysis of the data and the conclusions drawn. The data base consisted of a heterogeneous collection of 1449 paired ferrite measurements for several forms and combinations of types 304 and 316 stainless steel pipe qualification pad and production welds. Qualification pad values ranged from 5 to 15 FN, and corresponding values for the PWs ranged from 2.3 to 17.5 FN. Only two PW ferrite numbers were less than 3. For qualification weld ferrite numbers less than 14, the median PW ferrite number was in reasonable agreement. However, the results show a wide scatter. As a result of this analysis and the task group evaluation, we concluded that the requirements of Regulatory Guide 1.31 on the measurement of ferrite in PWs are not necessary and that a ferrite number of 5 in the qualification welds will, in most cases, result in PW ferrite contents greater than 3 FN.

  18. A Comparison of Creep Rupture Strength of Ferritic/Austenitic Dissimilar Weld Joints of Different Grades of Cr-Mo Ferritic Steels

    NASA Astrophysics Data System (ADS)

    Laha, K.; Chandravathi, K. S.; Parameswaran, P.; Goyal, Sunil; Mathew, M. D.

    2012-04-01

    Evaluations of creep rupture properties of dissimilar weld joints of 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb steels with Alloy 800 at 823 K were carried out. The joints were fabricated by a fusion welding process employing an INCONEL 182 weld electrode. All the joints displayed lower creep rupture strength than their respective ferritic steel base metals, and the strength reduction was greater in the 2.25Cr-1Mo steel joint and less in the 9Cr-1Mo steel joint. Failure location in the joints was found to shift from the ferritic steel base metal to the intercritical region of the heat-affected zone (HAZ) of the ferritic steel (type IV cracking) with the decrease in stress. At still lower stresses, the failure in the joints occurred at the ferritic/austenitic weld interface. The stress-life variation of the joints showed two-slope behavior and the slope change coincided with the occurrence of ferritic/austenitic weld interface cracking. Preferential creep cavitation in the soft intercritical HAZ induced type IV failure, whereas creep cavitation at the interfacial particles induced ferritic/austenitic weld interface cracking. Micromechanisms of the type IV failure and the ferritic/austenitic interface cracking in the dissimilar weld joint of the ferritic steels and relative cracking susceptibility of the joints are discussed based on microstructural investigation, mechanical testing, and finite element analysis (FEA) of the stress state across the joint.

  19. Influence of ferrite phase in alite-calcium sulfoaluminate cements

    NASA Astrophysics Data System (ADS)

    Duvallet, Tristana Yvonne Francoise

    Since the energy crisis in 1970's, research on low energy cements with low CO2- emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminateferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition

  20. Ferritic weldment of grain-refined ferritic steels for cryogenic service

    SciTech Connect

    Kim, H.J.; Morris, J.W. Jr.; Syn, C.K.

    1982-01-01

    This paper reports the initial results of the development of a weld filler metal and multipass GTA welding process for grain-refined 9Ni steel. The weld filler metal was cast in 4.5-kg ingots of the nominal composition Fe-14Ni-O.2Ti-0.003B, homogenized, hot-rolled, and then swaged into wire of 1.6-mm diameter. The chemical compositions of the base and filler metal are tabulated and the test welding procedure is described. Among the tests that were conducted on the welds are x-ray diffraction analysis for the residual austenite content; the Charpy impact test at 77 and 4.2 K for the fracture toughness; and scanning electron fractography for the weld metal, the HAZ, and the base metal of 9Ni Charpy specimens broken at 4.2 K. The procedure for grain refinement is defined; the retained austenite volume fraction is calculated using the method proposed by Miller. The results indicate that it is possible to weld grain-refined 9Ni steel with a ferritic weld filler metal and retain good toughness at cryogenic liquid helium temperatures.

  1. Pharmacokinetics of cefaclor AF: effects of age, antacids and H2-receptor antagonists.

    PubMed

    Satterwhite, J H; Cerimele, B J; Coleman, D L; Hatcher, B L; Kisicki, J; DeSante, K A

    1992-01-01

    The pharmacokinetics and bioavailability of cefaclor advanced formulation (cefaclor AF) were investigated in two studies, one comparing healthy elderly and younger volunteers and the other assessing the effects of an antacid and H2-receptor antagonist on cefaclor AF bioavailability. The pharmacokinetics of a 750 mg dose of cefaclor AF were studied in 30 subjects ranging in age from 65 to 84 years and 10 control subjects 21-45 years of age. Compared with controls, elderly subjects exhibited higher plasma concentrations of cefaclor which were attributed to lower plasma clearance. There was a strong association between age and renal function, and the plasma clearance of cefaclor was highly dependent upon renal function. Thus, elderly patients with impaired renal function had a reduced ability to eliminate cefaclor. Due to a short elimination half-life and wide therapeutic index, dosage adjustments are not necessary in patients exhibiting moderate renal dysfunction. The 15 healthy men in the second trial were crossed over to receive five treatments, including cefaclor AF (500 mg) alone, cefaclor AF with or preceded by cimetidine, cefaclor AF followed by Maalox TC and cefaclor immediate release (500 mg) alone. Cefaclor AF and immediate release cefaclor had similar bioavailability, but plasma concentrations were maintained for a longer period of time when cefaclor AF was administered. Cimetidine did not alter the bioavailability of cefaclor AF but Maalox TC, coadministered with cefaclor AF, reduced the extent of absorption. This suggests that cefaclor AF bioavailability is influenced by the antacid Maalox TC but not by H2-receptor antagonist cimetidine. PMID:1287615

  2. Effects of transformed ferrite growth on the tensile fracture characteristics of a dual-phase steel

    NASA Astrophysics Data System (ADS)

    Jeong, W. C.; Kim, C. H.

    1988-02-01

    The effects of transformed ferrite growth on the tensile fracture characteristics of a dual-phase steel were investigated by observing crack initiation, propagation, and fracture behaviors. Crack initiation occurred by decohesion between martensite and ferrite. However, cracks propagated along the ferrite-martensite interface in a high temperature quenched specimen, whereas in specimens quenched from lower temperature cracks propagated into the martensite particle. Tensile fracture behaviors were not strongly influenced by the cooling rate. At both cooling rates of 5.6 and 0.1 °C/sec, specimens quenched from high temperature fractured by partially brittle fracture mode, but fracture mode changed to ductile mode as the quenching temperature decreased. The effect of transformed ferrite on the fracture mode was not substantially different from that of retained ferrite. However, the crack initiation and propagation was influenced by the variation in martensite distribution caused by different growth behavior of transformed ferrite.

  3. Magnetic materials based on manganese zinc ferrite with surface-organized polyaniline coating

    NASA Astrophysics Data System (ADS)

    Kazantseva, N. E.; Bespyatykh, Yu. I.; Sapurina, I.; Stejskal, J.; Vilčáková, J.; Sáha, P.

    2006-06-01

    Core-shell composites of manganese-zinc (MnZn) ferrite and polyaniline (PANI) have been prepared by the oxidation of aniline with ammonium peroxydisulfate in the presence of ferrite. The various reaction conditions allowed controlling the thickness of PANI coating, 50-250 nm. Complex magnetic permeability spectra of MnZn ferrite of various particles sizes, 25-250 μm, and of their composites with PANI, have been studied in the frequency range 1 MHz-10 GHz. The formation of a polymer p-semiconducting nanolayer on the surface of a MnZn ferrite particle changes the character of the frequency dispersion of the permeability. The interfacial effects between MnZn ferrite and PANI nanofilm are responsible for the shifts of resonance frequency from MHz closer to GHz. This effect strongly depends on the specific area of the ferrite-PANI interface and, moreover, on the properties of the PANI overlayer.

  4. Hot-rolling of reduced activation 8CrODS ferritic steel

    NASA Astrophysics Data System (ADS)

    Wu, Xiaochao; Ukai, Shigeharu; Leng, Bin; Oono, Naoko; Hayashi, Shigenari; Sakasegawa, Hideo; Tanigawa, Hiroyasu

    2013-11-01

    The 8CrODS ferritic steel is based on J1-lot developed for the advanced fusion blanket material to increase the coolant outlet temperature. A hot-rolling was conducted at the temperature above Ar3 of 716 °C, and its effect on the microstructure and tensile strength in 8CrODS ferritic steel was evaluated, comparing together with normalized and tempered specimen. It was confirmed that hot-rolling leads to slightly increased fraction of the ferrite and highly improved tensile strength. This ferrite was formed by transformation from the hot-rolled austenite during cooling due to fine austenite grains induced by hot-rolling. The coarsening of the transformed ferrite in hot-rolled specimen can be attributed to the crystalline rotation and coalescence of the similar oriented grains. The improved strength of hot-rolled specimen was ascribed to the high dislocation density and replacement of easily deformed martensite with the transformed coarse ferrite.

  5. Field-dependent neutron depolarization study of the ferrite formation in medium-carbon steels

    SciTech Connect

    Te Velthuis, S.G.E.; Van Dijk, N.H.; Rekveldt, M.T.; Sietsma, J.; Van Der Zwaag, S.

    2000-03-14

    Neutron depolarization experiments have been performed on the ferrite and pearlite phase transformations of the medium-carbon C60 and C35 steels. The interaction of the polarized neutron beam with the ferromagnetic ferrite grains gives information on the mean magnetization and the magnetic correlation length. From these parameters the ferrite fraction and the mean ferrite grain size are determined in situ as a function of time and temperature during the phase transformation. The applied magnetic field was varied periodically in order to record a full hysteresis curve of the magnetization, which gives essential information on the microstructure of the ferromagnetic ferrite grains. The field dependence of the mean particle size during the early stages of the pearlite formation is a strong indication of multi-domain behavior, which is absent in the austenite-ferrite transformation and at the end of the pearlite formation.

  6. Dye removal using modified copper ferrite nanoparticle and RSM analysis.

    PubMed

    Mahmoodi, Niyaz Mohammad; Soltani-Gordefaramarzi, Sajjad; Sadeghi-Kiakhani, Moosa

    2013-12-01

    In this paper, copper ferrite nanoparticle (CFN) was synthesized, modified by cetyl trimethylammonium bromide, and characterized. Dye removal ability of the surface modified copper ferrite nanoparticle (SMCFN) from single system was investigated. The physical characteristics of SMCFN were studied using Fourier transform infrared, scanning electron microscopy, and X-ray diffraction. Acid Blue 92, Direct Green 6, Direct Red 23, and Direct Red 80 were used as model compounds. The effect of operational parameters (surfactant concentration, adsorbent dosage, dye concentration, and pH) on dye removal was evaluated. Response surface methodology (RSM) was used for the analysis of the dye removal data. The experimental checking in these optimal conditions confirms good agreements with RSM results. The results showed that the SMCFN being a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions. PMID:23852534

  7. Stress insensitive multilayer chip inductor with ferrite core

    SciTech Connect

    Vishwas, B.; Madhuri, W. Rao, N. Madhusudan; Kaleemulla, S.

    2015-06-24

    Mg{sub 0.25}Cu{sub 0.25}Zn{sub 0.5}Fe{sub 2}O{sub 4} is synthesized by sol gel auto combustion technique. The obtained ferrite powder is finally sintered in a microwave furnace at 850°C. Multilayer chip inductor (MLCI) of two layers is prepared by screen printing technique. The sintered ferrite is characterized by X-ray diffraction. The frequency response of dielectric constant is studied in the frequency range of 100Hz to 5MHz. Dielectric polarization is discussed in the light of Maxwell-Wagner interfacial polarization. The prepared MLCI is studied for stress sensitivity in the range of 0 to 8 MPa.

  8. The nucleation of austenite in ferritic ductile cast iron

    SciTech Connect

    Chou, J.M.; Hon, M.H. ); Lee, J.L. )

    1992-07-01

    Austempered ductile cast iron has recently been receiving increasing attention because of its excellent combination of strength and ductility. Since the austenitization process has a significant influence on the mechanical properties of austempered ductile cast iron, several investigations on the nucleation sites of austenite and diffusion paths of carbon from spheroidal graphite have been reported in ferritic ductile cast iron. However, agreement on this subject has not ben reached. The purpose of this paper is to study the preferential nucleation sites of austenite during austenitization at two austenitizing temperatures in ferritic ductile cast iron. An attempt was made to understand the reasons which give rise to preferential austenite nucleation sites. The carbon diffusion paths from spheroidal graphite were also investigated.

  9. Development of oxide dispersion strengthened ferritic steels for fusion

    SciTech Connect

    Mukhopadhyay, D.K.; Froes, F.H.; Gelles, D.S.

    1998-03-01

    An oxide dispersion strengthened (ODS) ferritic steel with high temperature strength has been developed in line with low activation criteria for application in fusion power systems. The composition Fe-13.5Cr-2W-0.5Ti-0.25Y{sub 2}O{sup 3} was chosen to provide a minimum chromium content to insure fully delta-ferrite stability. High temperature strength has been demonstrated by measuring creep response of the ODS alloy in uniaxial tension at 650 and 900 C in an inert atmosphere chamber. Results of tests at 900 C demonstrate that this alloy has creep properties similar to other alloys of similar design and can be considered for use in high temperature fusion power system designs. The alloy selection process, materials production, microstructural evaluation and creep testing are described.

  10. The Role of Alloying Elements in Nanostructured Ferritic Steels

    SciTech Connect

    Miller, Michael K; Parish, Chad M

    2010-01-01

    The roles of the alloying elements in three nanostructured ferritic alloys (14YWT, MA957 and Eurofer 97) have been established through the characterisation of the microstructure by atom probe tomography and spectrum imaging in a transmission electron microscope. Cr, W, Mo, Ti and Y were found in the ferrite matrix and contributed to solid solution hardening. Ti, Y, C, O and N were found in high number densities of precipitates and nanoclusters both in the grain interior and on grain boundaries and thereby contributed to precipitation hardening. Cr, W and Mo were enriched at the intraparticle regions of the grain boundaries. The solute segregation and precipitation pinned the grain boundaries and contributed to the excellent creep properties of the alloys.

  11. Ferritic/martensitic steels - overview of recent results

    NASA Astrophysics Data System (ADS)

    Klueh, R. L.; Gelles, D. S.; Jitsukawa, S.; Kimura, A.; Odette, G. R.; van der Schaaf, B.; Victoria, M.

    2002-12-01

    Considerable research work has been conducted on the ferritic/martensitic steels since the last International Conference on Fusion Reactor Materials in 1999. Since only a limited amount of that work can be reviewed in this paper, four areas will be emphasized: (1) the international collaboration under the auspices of the International Energy Agency (IEA) to address potential problems with ferritic/martensitic steels and to prove their feasibility for fusion, (2) the major uncertainty that remains concerning the effect of transmutation helium on mechanical properties of the steels when irradiated in a fusion neutron environment, (3) development of new reduced-activation steels beyond the F82H and JLF-1 steels studied in the IEA collaboration, and (4) work directed at developing oxide dispersion-strengthened steels for operation above 650 °C.

  12. Chemisorption of cyanogen chloride by spinel ferrite magnetic nanoparticles.

    PubMed

    Glover, T Grant; DeCoste, Jared B; Sabo, Daniel; Zhang, Z John

    2013-05-01

    Spinel ferrite magnetic nanoparticles, MnFe2O4, NiFe2O4, and CoFe2O4, were synthesized and used as gas-phase adsorbents for the removal of cyanogen chloride from dry air. Fixed-bed adsorption breakthrough experiments show adsorption wave behavior at the leading edge of the breakthrough curve that is not typical of physically adsorbed species. Fourier transform infrared spectroscopy (FTIR) results indicate that CK is reacting with the spinel ferrite surface and forming a carbamate species. The reaction is shown to be a function of the hydroxyl groups and adsorbed water on the surface of the particles as well as the metallic composition of the particles. The surface reaction decreases the remnant and saturation magnetism of the MnFe2O4 and CoFe2O4 particles by approximately 25%. PMID:23540752

  13. Studies on structural properties of clay magnesium ferrite nano composite

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Singh, Mandeep; Jeet, Kiran; Kaur, Rajdeep

    2015-08-01

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m2/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  14. Development of ferrite logic devices for an arithmetic processor

    NASA Technical Reports Server (NTRS)

    Heckler, C. H., Jr.

    1972-01-01

    A number of fundamentally ultra-reliable, all-magnetic logic circuits are developed using as a basis a single element ferrite structure wired as a logic delay element. By making minor additions or changes to the basic wiring pattern of the delay element other logic functions such as OR, AND, NEGATION, MAJORITY, EXCLUSIVE-OR, and FAN-OUT are developed. These logic functions are then used in the design of a full-adder, a set/reset flip-flop, and an edge detector. As a demonstration of the utility of all the developed devices, an 8-bit, all-magnetic, logic arithmetic unit capable of controlled addition, subtraction, and multiplication is designed. A new basic ferrite logic element and associated complementary logic scheme with the potential of improved performance is also described. Finally, an improved batch process for fabricating joint-free power drive and logic interconnect conductors for this basic class of all-magnetic logic is presented.

  15. Magnetic properties of nanocrystalline Ni Zn ferrites doped with samarium

    NASA Astrophysics Data System (ADS)

    Gama, L.; Diniz, A. P.; Costa, A. C. F. M.; Rezende, S. M.; Azevedo, A.; Cornejo, D. R.

    2006-10-01

    We describe the influence of the temperature of sintering on the structure and the static magnetic properties in Ni 0.5Zn 0.5Sm xFe 2-xO 4 ferrites prepared by combustion synthesis. The increase in Sm content increases the lattice parameter and decreases the mean grain size. The material treated at 600 °C should be single spinel ferrite but with low magnetization saturation. Calcinations carried out at 800 and 1000 °C resulted in materials with cubic spinel phase, but a small amount of SmFeO 3 was also formed. A smooth diminution of the saturation magnetization with an increase in Sm amount was observed. The highest Curie temperatures were obtained for sample treatment at 1000 °C with higher Sm content.

  16. Unusual Thermal Stability of Nano-structured Ferritic alloys

    SciTech Connect

    Wang, Xun-Li; Liu, Chain T; Stoica, A. D.; Keiderling, Dr. Uwe; Yang, Ling; Miller, Michael K; Fu, Chong Long; Ma, Dong; An, Ke

    2012-01-01

    A scientific question vitally important to the materials community is whether there exist self-assembled nanoclusters that are thermodynamically stable at elevated temperatures. Using in-situ neutron scattering, we characterized the structure and thermal stability of a nano-structured ferritic (NSF) alloy. Nanometer sized clusters were found to persist up to ~1400 C, providing direct evidence of a thermodynamically stable alloying state for the nanoclusters. Cluster formation requires the coexistence of Y, Ti, and O without the precipitation of oxide phases. The presence of thermally stable nanoclusters at grain boundaries limits the diffusion of Fe atoms, thereby stabilizing the microstructure of the ferritic matrix at high temperatures. Our experimental results provide physical insights of the dramatically improved high-temperature mechanical properties in NSF alloy and point to a new direction in alloy design.

  17. Studies on structural properties of clay magnesium ferrite nano composite

    SciTech Connect

    Kaur, Manpreet Singh, Mandeep; Jeet, Kiran Kaur, Rajdeep

    2015-08-28

    Magnesium ferrite-bentonite clay composite was prepared by sol-gel combustion method employing citric acid as complexing agent and fuel. The effect of clay on the structural properties was studied with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) Spectroscopy, Scanning electron microscopy (SEM), SEM- Energy dispersive Spectroscope (EDS) and BET surface area analyzer. Decrease in particle size and density was observed on addition of bentonite clay. The BET surface area of nano composite containing just 5 percent clay was 74.86 m{sup 2}/g. Whereas porosity increased from 40.5 per cent for the pure magnesium ferrite to 81.0 percent in the composite showing that nano-composite has potential application as an adsorbent.

  18. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    DOEpatents

    Leitnaker, J.M.

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 0.015 to 0.030 times the volume percent ferrite present in the alloy. The formation of chi phase upon aging is controlled by controlling the Mo content.

  19. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    DOEpatents

    Leitnaker, James M.

    1981-01-01

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 0.015-0.030 times the volume percent ferrite present in the alloy. The formation of chi phase upon aging is controlled by controlling the Mo content.

  20. New design concepts for ferrite-tuned low-energy-booster cavities

    SciTech Connect

    Schaffer, G.

    1991-05-01

    The design concepts for ferrite-tuned accelerating cavities discussed in this paper differ from conventional solutions using thick ferrite toroids for frequency tuning. Instead, tuners consisting of an array of ferrite-loaded striplines are investigated. These promise more efficient cooling and higher operational reliability. Layout examples for the SSC-LEB rf system are presented (tuning range 47.5 to 59.8 MHz, repetition frequency 10 Hz). 15 refs., 4 figs., 1 tab.

  1. Penipyridones A-F, Pyridone Alkaloids from Penicillium funiculosum.

    PubMed

    Zhou, Haibo; Li, Liyuan; Wu, Chongming; Kurtán, Tibor; Mándi, Attila; Liu, Yankai; Gu, Qianqun; Zhu, Tianjiao; Guo, Peng; Li, Dehai

    2016-07-22

    Six new pyridone alkaloids, named penipyridones A-F (1-6), were isolated from the fermentation broth of an Antarctic moss-derived fungus, Penicillium funiculosum GWT2-24. Their structures were elucidated from extensive NMR and MS data. Although they possess the same major chromophore and some of them presented almost mirror ECD spectra, their absolute configurations were found to be uniformly S, as evidenced by X-ray single-crystal diffraction analysis, stereocontrolled total synthesis, and chemical conversions. TDDFT-ECD calculations of compounds 3 and 6 revealed that subtle conformational changes are responsible for the significantly different ECD curves. None of the compounds were cytotoxic (IC50 > 50 μM), while compounds 1, 2, 5, and 7 elicited lipid-lowering activity in HepG2 hepatocytes. PMID:27359163

  2. Optimised secure transmission through untrusted AF relays using link adaptation

    NASA Astrophysics Data System (ADS)

    Taki, Mehrdad; Sadeghi, Mohammad

    2016-05-01

    A new transmission scheme is presented for a two-hop relay network including two AF relays, considering physical layer security where relays are not able to detect signal with an acceptable bit error rate (BER) but the combined received signal is detected with an acceptable BER at the final receiver. It is assumed that there is no direct path between the transmitter and the receiver (relay network without diversity). Adaptive modulation and coding is utilised at the transmitter and transmission powers of the transmitter and of the relays are continuously adapted provisioning individual average power constraint for each node. Numerical evaluations show that an acceptable performance degradation is seen by the proposed secure relaying scheme compared to the optimum relay selection scheme without security constraint.

  3. Anomalous ultrasonic attenuation in ferritic steels at elevated temperatures.

    PubMed

    Hutchinson, Bevis; Lundin, Peter; Lindh-Ulmgren, Eva; Lévesque, Daniel

    2016-07-01

    An unexpected peak in attenuation has been observed at ∼800°C when heating low carbon steels in a laser-ultrasonic instrument. An explanation is given in terms of enhanced crystalline anisotropy with increasing temperature in the bcc ferrite range combined with subsequent transformation to austenite at still higher temperatures. An analysis based on theoretical models of attenuation in the Rayleigh regime is in good agreement with the experimental observations. PMID:27015796

  4. Growth of Ferrite Needles in Compacted Graphite Cast Iron

    SciTech Connect

    Duran, G.A.; Mercader, R.C.; Desimoni, J.; Perez, T.; Gregorutti, R.W.

    2005-04-26

    The austempering kinetics transformation of compacted graphite cast irons austempered at 623K is studied. The length (l) and the number per unit volume (N) of ferrite needles were followed by Scanning Electron Microscopy (SEM), while Moessbauer spectroscopy (MS) was used to determine the austenite relative areas. The SEM results are compared with theoretical calculations available in the literature and indicate that the diffusion of C atoms in austenite controls the transformation, confirming the indirect MS determinations.

  5. Layer morphology and growth mechanisms in barium ferrites

    NASA Astrophysics Data System (ADS)

    Turner, G.; Stewart, B.; Baird, T.; Peacock, R. D.; Cairns-Smith, A. G.

    1996-01-01

    Crystals of hexagonal barium ferrites have been grown using a standard flux technique and, as a modification, on platinum tabs removed early from the hot flux. Products have been examined by SEM. Mature crystals often show highly laminated structures. Early crystals may consist of thin, somewhat flexible plates or slabs which overgrow themselves in ways which provide a possible explanation for the long c-axis repeats previously reported in these materials.

  6. Evaluation of the atoxigenic Aspergillus flavus strain AF36 in pistachio orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was a...

  7. Suitability of cation substituted cobalt ferrite materials for magnetoelastic sensor applications

    SciTech Connect

    Nlebedim, Ikenna Catjetan; Jiles, David C

    2015-02-01

    The results of a study on the suitability of materials derived from cobalt ferrite for sensor and actuator applications are presented. The mechanism responsible for the superior sensor properties of Ge-substituted cobalt ferrite compared with Ti and other cation substituted cobalt ferrite materials is believed to be due to the tetrahedral site preference of Ge4+ and its co-substitution with Co2+. Results also showed that the higher strain derivative of Ge-substituted cobalt ferrite compared with Ti-substitution is due to a higher magnetostrictive coupling in response to applied field in the material.

  8. Material for magnetostrictive sensors and other applications based on ferrite materials

    DOEpatents

    McCallum, R. William; Snyder, John E.; Dennis, Kevin W.; Schwichtenberg, Carl R.; Jiles, David C.

    2000-07-25

    The present invention provides magnetostrictive compositions that include an oxide ferrite which provides mechanical properties that make the magnetostrictive compositions effective for use as sensors and actuators.

  9. Method for making conductors for ferrite memory arrays. [from pre-formed metal conductors

    NASA Technical Reports Server (NTRS)

    Heckler, C. H.; Baba, P. D.; Bhiwandker, N. C. (Inventor)

    1974-01-01

    The ferrite memory arrays are made from pre-formed metal conductors for the ferrite arrays. The conductors are made by forming a thin sheet of a metallizing paste of metal alloy powder, drying the paste layer, bisque firing the dried sheet at a first temperature, and then punching the conductors from the fired sheet. During the bisque firing, the conductor sheet shrinks to 58 percent of its pre-fired volume and the alloy particles sinter together. The conductors are embedded in ferrite sheet material and finally fired at a second higher temperature during which firing the conductors shrink approximately the same degree as the ferrite material.

  10. Investigation of structural, dielectric, and magnetic properties of hard and soft mixed ferrite composites

    NASA Astrophysics Data System (ADS)

    Kotnala, R. K.; Ahmad, Shahab; Ahmed, Arham S.; Shah, Jyoti; Azam, Ameer

    2012-09-01

    Barium ferrite (hard ferrite) and manganese nickel zinc ferrite (soft ferrite) were successfully synthesized by citrate gel combustion technique. They were used to form the composites by mixing them properly in required compositions (x)BaFe12O19-(1-x)Mn0.2Ni0.4Zn0.4Fe2O4 (0 ≤ x ≤ 1). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to investigate the different structural and morphological parameters of pure and mixed ferrite composites. XRD and SEM results confirmed the coexistence of both phases in the composite material. Moreover, it has been observed that the composites were constituted by nanosized particles. Structure of pure soft ferrite was found to be cubic and that of pure hard ferrite was hexagonal. Dielectric constant (ɛ' and ɛ″) and dielectric loss (tan δ) were analyzed as a function of frequency and composition and the behaviour is explained on the basis of Maxwell-Wagner model. It was observed that the dielectric loss decreases with the increase of hard ferrite content in the composite material. Magnetic measurements suggest the exchange coupling between the magnetizations of soft and hard ferrite grains. It has been observed that the coercivity increases with the increase of the volume of the hard phase in the composite material after an optimal value.

  11. Giant piezomagnetism, piezocapacitance, and piezoimpedance effects in MnZn ferrite device under hydrostatic pressure

    NASA Astrophysics Data System (ADS)

    Zhang, N.; Fang, X.; Wang, Z. L.

    2008-07-01

    The effects of hydrostatic pressure on the magnetism, capacitance, and impedance of a manganese zinc ferrite device have been investigated. Giant piezomagnetism, piezocapacitance, and piezoimpedance that are independent of skin effects have been observed simultaneously under a pressure of a few megapascals. With increasing frequency of the current applied across the ferrite device, these pressure effects have been found to undergo a maximum at a frequency below 3kHz. Under a pressure of 6MPa, a piezoimpedance over 60% has been observed for the ferrite devices with permeabilities ranging from 5000 to 15 000. Analysis shows that these pressure effects result from the variation of the interior stress in the ferrite.

  12. Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

    SciTech Connect

    Rahman, Md. T. Ramana, C. V.

    2014-10-28

    Gadolinium (Gd) substituted cobalt ferrites (CoFe{sub 2−x}Gd{sub x}O{sub 4}, referred to CFGO) with variable Gd content (x = 0.0–0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectroscopy analysis was performed under a wide range of frequency (f = 20 Hz–1 MHz) and temperature (T = 303–573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe{sub 2}O{sub 4} due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and capacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics.

  13. Ferrite formation from photo-Fenton treated wastewater.

    PubMed

    Navarro, Ronald R; Ichikawa, Hiroyasu; Tatsumi, Kenji

    2010-06-01

    Photo-Fenton oxidation followed by ferrite formation was applied for the degradation of a representative organic compound, phenol, and the subsequent removal of the Fe ions. At a phenol:Fe(II):H(2)O(2) molar ratio of 1:0.5:15, TOC analysis showed almost complete mineralization of 10.6mM phenol after 2h at a controlled pH of 3. Recalcitrant low molecular weight organic acid by-products particularly oxalic acid were destroyed. A ferrous-rich solution was generated so that alkalinization at pH 10.5 generated a pitch black sludge of lower volume and moisture content than a ferric hydroxide control of the same Fe concentration. The flocs exhibited a strong affinity for a magnet and its X-ray diffraction pattern showed a close similarity to a standard spinel magnetite. With proper monitoring of Fe(II) and dissolved oxygen, the reaction was successfully controlled to generate flocs with more than 30% magnetite content. When photo-Fenton was employed as a pre-treatment step so that residual oxalic acid remained, ferrite formation was not inhibited. The presence of oxalates even allowed ferrites to form in a solution containing Ca(2+) ions, which is well-known to be deterrent to the process. PMID:20435331

  14. High-Performance Ferrite Nanoparticles through Nonaqueous Redox Phase Tuning.

    PubMed

    Chen, Ritchie; Christiansen, Michael G; Sourakov, Alexandra; Mohr, Alan; Matsumoto, Yuri; Okada, Satoshi; Jasanoff, Alan; Anikeeva, Polina

    2016-02-10

    From magnetic resonance imaging to cancer hyperthermia and wireless control of cell signaling, ferrite nanoparticles produced by thermal decomposition methods are ubiquitous across biomedical applications. While well-established synthetic protocols allow for precise control over the size and shape of the magnetic nanoparticles, structural defects within seemingly single-crystalline materials contribute to variability in the reported magnetic properties. We found that stabilization of metastable wüstite in commonly used hydrocarbon solvents contributed to significant cation disorder, leading to nanoparticles with poor hyperthermic efficiencies and transverse relaxivities. By introducing aromatic ethers that undergo radical decomposition upon thermolysis, the electrochemical potential of the solvent environment was tuned to favor the ferrimagnetic phase. Structural and magnetic characterization identified hallmark features of nearly defect-free ferrite nanoparticles that could not be demonstrated through postsynthesis oxidation with nearly 500% increase in the specific loss powers and transverse relaxivity times compared to similarly sized nanoparticles containing defects. The improved crystallinity of the nanoparticles enabled rapid wireless control of intracellular calcium. Our work demonstrates that redox tuning during solvent thermolysis can generate potent theranostic agents through selective phase control in ferrites and can be extended to other transition metal oxides relevant to memory and electrochemical storage devices. PMID:26756463

  15. Isomorphism of actinides and REE in synthetic ferrite garnets

    NASA Astrophysics Data System (ADS)

    Livshits, T. S.

    2010-02-01

    The reprocessing of spent nuclear fuel (SNF) is accompanied by the formation of liquid high-level radioactive waste (HLW). To increase the safety of handling HLW, it is proposed to extract actinide isotopes (An) and REE from them. These elements may be incorporated into crystalline matrices, e.g., based on ferrites with garnet structure, and then disposed in a geologic repository. The actinide-REE fraction is characterized by a complex composition. In addition to major components (An and REE), Al, Si, Na, and Sn occur therein in small amounts (a few wt %). Possible incorporation of the admixtures into ferrite garnets, as well as their effect on the phase composition of matrices and Th, Ce, Gd, and La contents were studied. It was shown that admixtures enter into garnet by means of isomorphic replacement. The properties of samples change only when admixtures are added in amounts exceeding their concentrations in HLW. The ability of ferrite garnets to accumulate significant amounts of An, REE, and admixture elements makes them suitable for use as matrices in immobilizing actinide-REE HLW of complex composition.

  16. Antimicrobial Lemongrass Essential Oil-Copper Ferrite Cellulose Acetate Nanocapsules.

    PubMed

    Liakos, Ioannis L; Abdellatif, Mohamed H; Innocenti, Claudia; Scarpellini, Alice; Carzino, Riccardo; Brunetti, Virgilio; Marras, Sergio; Brescia, Rosaria; Drago, Filippo; Pompa, Pier Paolo

    2016-01-01

    Cellulose acetate (CA) nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG) essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs), with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities. PMID:27104514

  17. Study of Zn-Cu Ferrite Nanoparticles for LPG Sensing

    PubMed Central

    Jain, Anuj; Baranwal, Ravi Kant; Bharti, Ajaya; Vakil, Z.; Prajapati, C. S.

    2013-01-01

    Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. XRD patterns of different compositions of zinc-copper ferrite, Zn(1−x)CuxFe2O4 (x = 0.0, 0.25, 0.50, 0.75), revealed single phase inverse spinel ferrite in all the samples synthesized. With increasing copper concentration, the crystallite size was found to be increased from 28 nm to 47 nm. The surface morphology of all the samples studied by the Scanning Electron Microscopy there exhibits porous structure of particles throughout the samples. The pellets of the samples are prepared for LPG sensing characteristics. The sensing is carried out at different operating temperatures (200, 225, and 250°C) with the variation of LPG concentrations (0.2, 0.4, and 0.6 vol%). The maximum sensitivity of 55.33% is observed at 250°C operating for the 0.6 vol% LPG. PMID:23864833

  18. Evidence of domain wall pinning in aluminum substituted cobalt ferrites

    NASA Astrophysics Data System (ADS)

    Maurya, J. C.; Janrao, P. S.; Datar, A. A.; Kanhe, N. S.; Bhoraskar, S. V.; Mathe, V. L.

    2016-08-01

    In the present work spinel structured cobalt ferrites with aluminum substitution having composition CoAlxFe2-xO4 (x=0.0, 0.1, 0.2 and 0.3) have been synthesized using chemical co-precipitation method. Their microstructural, magnetic, magnetostriction and magnetoimpedance properties have been investigated. The piezomagnetic coefficient (dλ/dH) obtained from magnetostriction data is found to enhance with 0.1 Al substitutions in place of iron which decreases with further increase of Al content. It is noticed that 0.3 Al substitutions in place of Fe introduces domain wall pinning as evidenced from magnetostriction, magnetoimpedance and dc magnetization data. It is noted that ferrites so prepared using a simple procedure are magnetostrictive in good measure and with the addition of very small amount of non-magnetic aluminum their magnetostriction has shown saturation at relatively low magnetic fields. Such magnetostrictive ferrites find their applications in magnetic sensors and actuators.

  19. Mechanical alloying of lanthana-bearing nanostructured ferritic steels

    SciTech Connect

    Somayeh Paseban; Indrajit Charit; Yaqiao Q. Wu; Jatuporn Burns; Kerry N. Allahar; Darryl P. Butt; James I. Cole

    2013-09-01

    A novel nanostructured ferritic steel powder with the nominal composition Fe–14Cr–1Ti–0.3Mo–0.5La2O3 (wt.%) was developed via high energy ball milling. La2O3 was added to this alloy instead of the traditionally used Y2O3. The effects of varying the ball milling parameters, such as milling time, steel ball size and ball to powder ratio, on the mechanical properties and micro structural characteristics of the as-milled powder were investigated. Nanocrystallites of a body-centered cubic ferritic solid solution matrix with a mean size of approximately 20 nm were observed by transmission electron microscopy. Nanoscale characterization of the as-milled powder by local electrode atom probe tomography revealed the formation of Cr–Ti–La–O-enriched nanoclusters during mechanical alloying. The Cr:Ti:La:O ratio is considered “non-stoichiometric”. The average size (radius) of the nanoclusters was about 1 nm, with number density of 3.7 1024 m3. The mechanism for formation of nanoclusters in the as-milled powder is discussed. La2O3 appears to be a promising alternative rare earth oxide for future nanostructured ferritic steels.

  20. Perpendicular Biased Ferrite Tuned Cavities for the Fermilab Booster

    SciTech Connect

    Romanov, Gennady; Awida, Mohamed; Khabiboulline, Timergali; Pellico, William; Tan, Cheng-Yang; Terechkine, Iouri; Yakovlev, Vyacheslav; Zwaska, Robert

    2014-07-01

    The aging Fermilab Booster RF system needs an upgrade to support future experimental program. The important feature of the upgrade is substantial enhancement of the requirements for the accelerating cavities. The new requirements include enlargement of the cavity beam pipe aperture, increase of the cavity voltage and increase in the repetition rate. The modification of the present traditional parallel biased ferrite cavities is rather challenging. An alternative to rebuilding the present Fermilab Booster RF cavities is to design and construct new perpendicular biased RF cavities, which potentially offer a number of advantages. An evaluation and a preliminary design of the perpendicular biased ferrite tuned cavities for the Fermilab Booster upgrade is described in the paper. Also it is desirable for better Booster performance to improve the capture of beam in the Booster during injection and at the start of the ramp. One possible way to do that is to flatten the bucket by introducing second harmonic cavities into the Booster. This paper also looks into the option of using perpendicularly biased ferrite tuners for the second harmonic cavities.

  1. Magnetic and magnetostrictive properties of Cu substituted Co-ferrites

    NASA Astrophysics Data System (ADS)

    Chandra Sekhar, B.; Rao, G. S. N.; Caltun, O. F.; Dhana Lakshmi, B.; Parvatheeswara Rao, B.; Subba Rao, P. S. V.

    2016-01-01

    Copper substituted cobalt ferrite, Co1-xCuxFe2O4 (x=0.00-0.25), nanoparticles were synthesized by sol-gel autocombustion method. X-ray diffraction analysis on the samples was done to confirm the cubic spinel structures and Scherrer equation was used to estimate the mean crystallite size as 40 nm. Using the obtained nanoparticles, fabrication of the sintered pellets was done by standard ceramic technique. Magnetic and magnetostrictive measurements on the samples were made by strain gauge and vibrating sample magnetometer techniques, respectively. Maximum magnetostriction and strain derivative values were deduced from the field dependent magnetostriction curves while the magnetic parameters such as saturation magnetization (51.7-61.9 emu/g) and coercivity (1045-1629 Oe) on the samples were estimated from the obtained magnetic hysteresis loops. Curie temperature values (457-315 °C) were measured by a built in laboratory set-up. Copper substituted cobalt ferrites have shown improved strain derivative values as compared to the pure cobalt ferrite and thus making them suitable for stress sensing applications. The results have been explained on the basis of cationic distributions, strength of exchange interactions and net decreased anisotropic contributions due to the increased presence of Co2+ ions in B-sites as a result of Cu substitutions.

  2. Mutant U2AF1 Expression Alters Hematopoiesis and Pre-mRNA Splicing In Vivo

    PubMed Central

    Shirai, Cara Lunn; Ley, James N.; White, Brian S.; Kim, Sanghyun; Tibbitts, Justin; Shao, Jin; Ndonwi, Matthew; Wadugu, Brian; Duncavage, Eric J.; Okeyo-Owuor, Theresa; Liu, Tuoen; Griffith, Malachi; McGrath, Sean; Magrini, Vincent; Fulton, Robert S.; Fronick, Catrina; O’Laughlin, Michelle; Graubert, Timothy A.; Walter, Matthew J.

    2015-01-01

    SUMMARY Heterozygous somatic mutations in the spliceosome gene U2AF1 occur in ~11% of patients with myelodysplastic syndromes (MDS), the most common adult myeloid malignancy. It is unclear how these mutations contribute to disease. We examined in vivo hematopoietic consequences of the most common U2AF1 mutation using a doxycycline-inducible transgenic mouse model. Mice expressing mutant U2AF1(S34F) display altered hematopoiesis and changes in pre-mRNA splicing in hematopoietic progenitor cells by whole transcriptome analysis (RNA-seq). Integration with human RNA-seq datasets determined that common mutant U2AF1-induced splicing alterations are enriched in RNA processing genes, ribosomal genes, and recurrently-mutated MDS and acute myeloid leukemia-associated genes. These findings support the hypothesis that mutant U2AF1 alters downstream gene isoform expression, thereby contributing to abnormal hematopoiesis in MDS patients. PMID:25965570

  3. Atrial Fibrillation Management Strategies in Routine Clinical Practice: Insights from the International RealiseAF Survey

    PubMed Central

    Chiang, Chern-En; Naditch-Brûlé, Lisa; Brette, Sandrine; Silva-Cardoso, José; Gamra, Habib; Murin, Jan; Zharinov, Oleg J.; Steg, Philippe Gabriel

    2016-01-01

    Background Atrial fibrillation (AF) can be managed with rhythm- or rate-control strategies. There are few data from routine clinical practice on the frequency with which each strategy is used and their correlates in terms of patients’ clinical characteristics, AF control, and symptom burden. Methods RealiseAF was an international, cross-sectional, observational survey of 11,198 patients with AF. The aim of this analysis was to describe patient profiles and symptoms according to the AF management strategy used. A multivariate logistic regression identified factors associated with AF management strategy at the end of the visit. Results Among 10,497 eligible patients, 53.7% used a rate-control strategy, compared with 34.5% who used a rhythm-control strategy. In 11.8% of patients, no clear strategy was stated. The proportion of patients with AF-related symptoms (EHRA Class > = II) was 78.1% (n = 4396/5630) for those using a rate-control strategy vs. 67.8% for those using a rhythm-control strategy (p<0.001). Multivariate logistic regression analysis revealed that age <75 years or the paroxysmal or persistent form of AF favored the choice of a rhythm-control strategy. A change in strategy was infrequent, even in patients with European Heart Rhythm Association (EHRA) Class > = II. Conclusions In the RealiseAF routine clinical practice survey, rate control was more commonly used than rhythm control, and a change in strategy was uncommon, even in symptomatic patients. In almost 12% of patients, no clear strategy was stated. Physician awareness regarding optimal management strategies for AF may be improved. PMID:26800084

  4. Lessons from the dissection of the activation functions (AF-1 and AF-2) of the estrogen receptor alpha in vivo.

    PubMed

    Arnal, Jean-François; Fontaine, Coralie; Abot, Anne; Valera, Marie-Cécile; Laurell, Henrik; Gourdy, Pierre; Lenfant, Françoise

    2013-06-01

    Estrogens influence most of the physiological processes in mammals, including but not limited to reproduction, cognition, behavior, vascular system, metabolism and bone integrity. Given this widespread role for estrogen in human physiology, it is not surprising that estrogen influence the pathophysiology of numerous diseases, including cancer (of the reproductive tract as breast, endometrial but also colorectal, prostate,…), as well as neurodegenerative, inflammatory-immune, cardiovascular and metabolic diseases, and osteoporosis. These actions are mediated by the activation of estrogen receptors (ER) alpha (ERα) and beta (ERβ), which regulate target gene transcription (genomic action) through two independent activation functions (AF)-1 and AF-2, but can also elicit rapid membrane initiated steroid signals (MISS). Targeted ER gene inactivation has shown that although ERβ plays an important role in the central nervous system and in the heart, ERα appears to play a prominent role in most of the other tissues. Pharmacological activation or inhibition of ERα and/or ERβ provides already the basis for many therapeutic interventions, from hormone replacement at menopause to prevention of the recurrence of breast cancer. However, the use of these estrogens or selective estrogen receptors modulators (SERMs) have also induced undesired effects. Thus, an important challenge consists now to uncouple the beneficial actions from other deleterious ones. The in vivo molecular "dissection" of ERα represents both a molecular and integrated approach that already allowed to delineate in mouse the role of the main "subfunctions" of the receptor and that could pave the way to an optimization of the ER modulation. PMID:23200732

  5. Calculation of the standard heat capacity at constant pressure for cobalt ferrite-zinc ferrite solid solutions

    SciTech Connect

    Chachanidze, G.D.; Pavlenishvili, T.A.; Machaladze, T.E.; Khutsishvili, D.I.

    1994-08-01

    Magnetic, electrical, and other properties of Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} solid solutions are widely studied because of their high coercive force and Curie temperature ({Tc}), which makes these compounds applicable in modern electronic devices. However, the information published on their thermodynamic properties is limited. This paper focuses on calculation of the standard heat capacity C{sub p}{sup 0} (298 K) for cobalt zinc ferrites using correlation analysis of the relationship between C{sub p}{sup 0} (298 K) and the saturation magnetic moment {mu}{sub o}. The authors studied the solid solutions Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} (x = 0.2, 0.4, 0.5, 0.6, and 0.8), whose magnetic and thermal parameters, crucial in our calculations, are known to be strongly dependent on the preparation conditions. An equation was derived for calculation of the standard heat capacity at constant pressure from the saturation magnetic moment of Co{sub 1-x}Zn{sub x}Fe{sub 2}O{sub 4} solid solutions. The equation allows a satisfactory estimation of the standard heat capacity at 298 Kelvin for any cobalt ferrite-zinc ferrite solid, providing the saturation magnetic moment is available.

  6. Copper ferrite nanoparticle-induced cytotoxicity and oxidative stress in human breast cancer MCF-7 cells.

    PubMed

    Ahamed, Maqusood; Akhtar, Mohd Javed; Alhadlaq, Hisham A; Alshamsan, Aws

    2016-06-01

    Copper ferrite (CuFe2O4) nanoparticles (NPs) are important magnetic materials currently under research due to their applicability in nanomedicine. However, information concerning the biological interaction of copper ferrite NPs is largely lacking. In this study, we investigated the cellular response of copper ferrite NPs in human breast cancer (MCF-7) cells. Copper ferrite NPs were prepared by co-precipitation technique with the thermal effect. Prepared NPs were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and dynamic light scattering (DLS). Characterization data showed that copper ferrite NPs were crystalline, spherical with smooth surfaces and average diameter of 15nm. Biochemical studies showed that copper ferrite NPs induce cell viability reduction and membrane damage in MCF-7 cells and degree of induction was dose- and time-dependent. High SubG1 cell population during cell cycle progression and MMP loss with a concomitant up-regulation of caspase-3 and caspase-9 genes suggested that copper ferrite NP-induced cell death through mitochondrial pathway. Copper ferrite NP was also found to induce oxidative stress in MCF-7 cells as indicated by reactive oxygen species (ROS) generation and glutathione depletion. Cytotoxicity due to copper ferrite NPs exposure was effectively abrogated by N-acetyl-cysteine (ROS scavenger) suggesting that oxidative stress could be the plausible mechanism of copper ferrite NPs toxicity. Further studies are underway to explore the toxicity mechanisms of copper ferrite NPs in different types of human cells. This study warrants further generation of extensive biointeraction data before their application in nanomedicine. PMID:26925725

  7. A role of {delta}-ferrite in edge-crack formation during hot-rolling of austenitic stainless steels

    SciTech Connect

    Czerwinski, F.; Brodtka, A.; Cho, J.Y.; Szpunar, J.A.; Zielinska-Lipiec, A.; Sunwoo, J.H.

    1997-10-15

    Austenitic stainless steels are substantially harder during hot-rolling than either ferritic or mild steels. The objective of this study is to verify the possible correlation between the edge-crack formation during hot-rolling and the presence of {delta} ferrite in austenitic stainless steel. Hot-rolled plates of austenitic stainless steels, examined at room temperatures, contain up to 9% of {delta} ferrite in austenitic matrix. The distribution of ferrite in steel plate is inhomogeneous: the highest ferrite content is located in the vicinity of the plate edge. Moreover, the content of {delta} ferrite changes irregularly across the plate thickness. The results obtained from analysis of several plates suggest a correlation between the maximum content of {delta} ferrite in steel microstructure and the length of the edge-crack formed during hot-rolling: the higher the volume fraction of ferrite, the longer the edge-crack.

  8. Hsp90 Directly Modulates the Spatial Distribution of AF9/MLLT3 and Affects Target Gene Expression*

    PubMed Central

    Lin, Jeffrey J.; Hemenway, Charles S.

    2010-01-01

    AF9/MLLT3 contributes to the regulation of the gene encoding the epithelial sodium channel α, ENaCα, in renal tubular cells. Specifically, increases in AF9 protein lead to a reduction in ENaCα expression and changes in AF9 activity appear to be an important component of aldosterone signaling in the kidney. Whereas AF9 is found in the nucleus where it interacts with the histone H3 lysine 79 methyltransferase, Dot1, AF9 is also present in the cytoplasm. Data presented in this report indicate that the heat shock protein Hsp90 directly and specifically interacts with AF9 as part of an Hsp90-Hsp70-p60/Hop chaperone complex. Experimental manipulation of Hsp90 function by the inhibitor novobiocin, but not 17-AAG, results in redistribution of AF9 from a primarily nuclear to cytoplasmic location. Knockdown of Hsp90 with siRNA mimics the effect elicited by novobiocin. As expected, a shift in AF9 from the nucleus to the cytoplasm in response to Hsp90 interference leads to increased ENaCα expression. This is accompanied by a decrease in AF9 occupancy at the ENaCα promoter. Our data suggest that the interaction of Hsp90, Hsp70, and p60/Hop with AF9 is necessary for the proper subnuclear localization and activity of AF9. AF9 is among a growing number of nuclear proteins recognized to rely on the Hsp90 complex for nuclear targeting. PMID:20159978

  9. [Factor AF2--the 4th column in tumor therapy. Documentation No.22].

    PubMed

    Kast, A; Hauser, S P

    1990-04-17

    Factor AF2 is an extract from the spleen and liver of sheep embryos and lambs. The product contains biotechnologically produced, chromatographically uniform, molecularly standardized polypeptides, glycopeptides, glycolipids and nucleotides, deproteinized and free of pyrogens'. Factor AF2 is intended mainly for use in 'supportive antitumour therapy', as a 'biological antiemetic and analgesic'. The proposed duration of treatment is usually more than six months. The dosage varies considerably according to the indication. The average daily costs are, therefore, between DM 4.- (prevention of recurrence) and DM 107.- (adjuvant to chemotherapy). Allergic reactions have been reported in 'rare cases'. Factor AF2 was developed in the forties by Guarnieri in Rome. Since 1984, Factor AF2 is 'biotechnologically' produced and as a 'biological response modifier' (BRM) in the oncotherapy distributed by Biosyn Arzneimittel GmbH, Stuttgart. Dr. rer. nat. T. Stiefel and Dr. rer. nat. H. Porcher are the representatives of Biosyn Arzneimittel GmbH. In the past, both worked with Vitorgan Arzneimittel GmbH (cytoplasmatic therapy according to Theurer). It is claimed that Factor AF2 contains 'immunomodulating and immunorestorative biomolecules' assignable to the BRM group. Terms and investigations from current immunological research are applied to Factor AF2. No preclinical investigations are available which demonstrate any cytostatic effect of Factor AF2. In vivo, no effects were observed on the transplanted meth-A-sarcoma in mice.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2349412

  10. The Ras Target AF-6 is a Substrate of the Fam Deubiquitinating Enzyme

    PubMed Central

    Taya, Shinichiro; Yamamoto, Takaharu; Kano, Kyoko; Kawano, Yoji; Iwamatsu, Akihiro; Tsuchiya, Tomoko; Tanaka, Keiji; Kanai-Azuma, Masami; Wood, Stephen A.; Mattick, John S.; Kaibuchi, Kozo

    1998-01-01

    The Ras target AF-6 has been shown to serve as one of the peripheral components of cell–cell adhesions, and is thought to participate in cell–cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of ∼220 kD (p220) to investigate the function of AF-6 at cell–cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell–cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6. PMID:9722616

  11. Critical behavior of a triangular lattice Ising AF/FM bilayer

    NASA Astrophysics Data System (ADS)

    Žukovič, M.; Bobák, A.

    2016-03-01

    We study a bilayer Ising spin system consisting of antiferromagnetic (AF) and ferromagnetic (FM) triangular planes, coupled by ferromagnetic exchange interaction, by standard Monte Carlo and parallel tempering methods. The AF/FM bilayer is found to display the critical behavior completely different from both the single FM and AF constituents as well as the FM/FM and AF/AF bilayers. Namely, by finite-size scaling (FSS) analysis we identify at the same temperature a standard Ising transition from the paramagnetic to FM state in the FM plane that induces a ferrimagnetic state with a finite net magnetic moment in the AF plane. At lower temperatures there is another phase transition, that takes place only in the AF plane, to different ferrimagnetic state with spins on two sublattices pointing parallel and on one sublattice antiparallel to the spins on the FM plane. FSS indicates that the corresponding critical exponents are close to the two-dimensional three-state ferromagnetic Potts model values.

  12. U2AF1 Mutations Alter Sequence Specificity of pre-mRNA Binding and Splicing

    PubMed Central

    Okeyo-Owuor, Theresa; White, Brian S.; Chatrikhi, Rakesh; Mohan, Dipika R.; Kim, Sanghyun; Griffith, Malachi; Ding, Li; Ketkar-Kulkarni, Shamika; Hundal, Jasreet; Laird, Kholiswa M.; Kielkopf, Clara L.; Ley, Timothy J.; Walter, Matthew J.; Graubert, Timothy A.

    2014-01-01

    We previously identified missense mutations in the U2AF1 splicing factor affecting codons S34 (S34F and S34Y) or Q157 (Q157R and Q157P) in 11% of patients with de novo myelodysplastic syndromes (MDS). Although the role of U2AF1 as an accessory factor in the U2 snRNP is well established, it is not yet clear how mutations affect splicing or contribute to MDS pathophysiology. We analyzed splice junctions in RNA-seq data generated from transfected CD34+ hematopoietic cells and found significant differences in the abundance of known and novel junctions in samples expressing mutant U2AF1 (S34F). For selected transcripts, splicing alterations detected by RNA-seq were confirmed by analysis of primary de novo MDS patient samples. These effects were not due to impaired U2AF1 (S34F) localization as it co-localized normally with U2AF2 within nuclear speckles. We further found evidence in the RNA-seq data for decreased affinity of U2AF1 (S34F) for uridine (relative to cytidine) at the e-3 position immediately upstream of the splice acceptor site and corroborated this finding using affinity binding assays. These data suggest that the S34F mutation alters U2AF1 function in the context of specific RNA sequences, leading to aberrant alternative splicing of target genes, some of which may be relevant for MDS pathogenesis. PMID:25311244

  13. Ternary complex formation and competition quench fluorescence of ZnAF family zinc sensors.

    PubMed

    Staszewska, Anna; Kurowska, Ewa; Bal, Wojciech

    2013-11-01

    Our current understanding of the intracellular thermodynamics and kinetics of Zn(ii) ions is largely based on the application of fluorescent sensor molecules, used to study and visualize the concentration, distribution and transport of Zn(ii) ions in real time. Such agents are designed for high selectivity for zinc in respect to other biological metal ions. However, the issue of their sensitivity to physiological levels of low molecular weight Zn(ii) ligands (LMWLs) has not been addressed. We followed the effects of eight such compounds on the fluorescence of ZnAF-1 and ZnAF-2F, two representatives of the ZnAF family of fluorescein-based zinc sensors containing the N,N-bis(2-pyridylmethyl)ethylenediamine chelating unit. Fluorescence titrations of equimolar Zn(ii)-ZnAF-1 and Zn(ii)-ZnAF-2F solutions with acetate, phosphate, citrate, glycine, glutamic acid, histidine, ATP and GSH demonstrated strong fluorescence quenching. These results are interpreted in terms of an interplay of the formation of the [ZnAF-Zn(ii)-LMWL] ternary complexes and the competition for Zn(ii) between ZnAF and LMWLs. UV-vis spectroscopic titrations revealed the existence of supramolecular interactions between the fluorescein moiety of ZnAF-1 and ATP and His, which, however, did not contribute to fluorescence quenching. Therefore, the obtained results show that the ZnAF sensors, other currently used zinc sensors containing the N,N-bis(2-pyridylmethyl)ethylenediamine unit, and, in general, all sensors that do not saturate the Zn(ii) coordination sphere may co-report cellular metabolites and Zn(ii) ions, leading to misrepresentations of the concentrations and fluxes of biological zinc. PMID:23939683

  14. Hospitalizations in patients with atrial fibrillation: an analysis from ROCKET AF

    PubMed Central

    DeVore, Adam D.; Hellkamp, Anne S.; Becker, Richard C.; Berkowitz, Scott D.; Breithardt, Guenter; Hacke, Werner; Halperin, Jonathan L.; Hankey, Graeme J.; Mahaffey, Kenneth W.; Nessel, Christopher C.; Singer, Daniel E.; Fox, Keith A. A.; Patel, Manesh R.; Piccini, Jonathan P.

    2016-01-01

    Aims The high costs associated with treatment for atrial fibrillation (AF) are primarily due to hospital care, but there are limited data to understand the reasons for and predictors of hospitalization in patients with AF. Methods and results The ROCKET AF trial compared rivaroxaban with warfarin for stroke prophylaxis in AF. We described the frequency of and reasons for hospitalization during study follow-up and utilized Cox proportional hazards models to assess for baseline characteristics associated with all-cause hospitalization. Of 14 171 patients, 14% were hospitalized at least once. Of 2614 total hospitalizations, 41% were cardiovascular including 4% for AF; of the remaining, 12% were for bleeding. Compared with patients not hospitalized, hospitalized patients were older (74 vs. 72 years), and more frequently had diabetes (46 vs. 39%), prior MI (23 vs. 16%), and paroxysmal AF (19 vs. 17%), but less frequently had prior transient ischaemic attack/stroke (49 vs. 56%). After multivariable adjustment, lung disease [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.29–1.66], diabetes [1.22, (1.11–1.34)], prior MI [1.27, (1.13–1.42)], and renal dysfunction [HR 1.07 per 5 unit GFR < 65 mL/min, (1.04–1.10)] were associated with increased hospitalization risk. Treatment assignment was not associated with differential rates of hospitalization. Conclusion Nearly 1 in 7 of the moderate-to-high-risk patients with AF enrolled in this trial was hospitalized within 2 years, and both AF and bleeding were rare causes of hospitalization. Further research is needed to determine whether care pathways directed at comorbid conditions among AF patients could reduce the need for and costs associated with hospitalization. PMID:27174904

  15. Modeling Direct and Inverse Problems in Ferritic Heat-Exchanger Tubes

    NASA Astrophysics Data System (ADS)

    Sabbagh, Harold A.; Murphy, R. Kim; Sabbagh, Elias H.; Aldrin, John C.

    2011-06-01

    In this paper, we present examples of direct and inverse problems involving ferritic tubes, using the proprietary eddy-current NDE code, VIC-3D©. We demonstrate conditions that are peculiar to ferritic tubes, and give insight into the optimum methods for characterizing the tubes and flaws within them.

  16. 40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Styrenyl surface treated manganese... Specific Chemical Substances § 721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical... as styrenyl surface treated manganese ferrite (PMN P-09-581) is subject to reporting under...

  17. 40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Styrenyl surface treated manganese... Specific Chemical Substances § 721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical... as styrenyl surface treated manganese ferrite (PMN P-09-581) is subject to reporting under...

  18. 40 CFR 721.10222 - Styrenyl surface treated manganese ferrite (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Styrenyl surface treated manganese... Specific Chemical Substances § 721.10222 Styrenyl surface treated manganese ferrite (generic). (a) Chemical... as styrenyl surface treated manganese ferrite (PMN P-09-581) is subject to reporting under...

  19. Interaction of magnetoacoustic waves with flux-line lattice in superconducting-ferrite layered structure

    SciTech Connect

    Sayko, G.V.; Bugaev, A.S.; Popkov, A.F.

    1994-12-31

    The authors consider vortex lattice interaction with transverse surface magnetoacoustic wave in high-{Tc} superconductor-ferrite structure. It has been found that the magnetoacoustic waves excited in the ferrite can be efficiently coupled with vortex structure in superconducting film. The nonlinear effect of vortex drift as well as the possibility of the wave amplification are discussed.

  20. 78 FR 63517 - Control of Ferrite Content in Stainless Steel Weld Metal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... Information The NRC published DG-1279 in the Federal Register on October 3, 2012 (77 FR 60479), for a 60-day... COMMISSION Control of Ferrite Content in Stainless Steel Weld Metal AGENCY: Nuclear Regulatory Commission... revision to Regulatory Guide (RG) 1.31, ``Control of Ferrite Content in Stainless Steel Weld Metal.''...

  1. Nano-ferrites for Water Splitting: Unprecedented High Photocatalytic Hydrogen Production under Visible Light

    EPA Science Inventory

    In the present investigation, hydrogen production via water splitting by nano ferrites has been studied using ethanol as the sacrificial donor. The nano ferrite has shown great potential in hydrogen generation with hydrogen yield of 8275 9moles/h/ g of photocatalyst under visible...

  2. The Effect of Interfacial Element Partitioning on Ferrite and Bainite Formation

    NASA Astrophysics Data System (ADS)

    Chen, Hao; van der Zwaag, Sybrand

    2016-05-01

    The formation of bainitic ferrite and that of grain boundary ferrite in low alloy steels have been two of the most important and interesting research topics in the field of solid state ferrous phase transformation for several decades, and various aspects of these two transformations have been discussed extensively in the literature. Recently, a so-called Gibbs energy balance (GEB) model was proposed by the authors to evaluate alloying element effects on the growth of bainitic ferrite and grain boundary ferrite. The model predicts a growth mode transition from paraequilibrium, negligible partitioning to partitioning during the isothermal formation of bainitic ferrite and grain boundary ferrite. Transformation stasis and bay phenomenon are well explained by the GEB model and both of them are found to be due to alloying element diffusion at the interface. This overview gives a summary of the authors' recent progress in the understanding of the growth of bainitic ferrite and grain boundary ferrite, with particular focus on the growth mode transition, the transformation stasis phenomenon and the bay phenomenon.

  3. The Inhibition of Inflammasome by Brazilian Propolis (EPP-AF)

    PubMed Central

    Hori, Juliana I.; Zamboni, Dario S.; Carrão, Daniel B.; Goldman, Gustavo Henrique; Berretta, Andresa A.

    2013-01-01

    Propolis extracts have gained the attention of consumers and researchers due to their unique chemical compositions and functional properties such as its anti-inflammatory activity. Recently, it was described a complex that is also important in inflammatory processes, named inflammasome. The inflammasomes are a large molecular platform formed in the cell cytosol in response to stress signals, toxins, and microbial infections. Once activated, the inflammasome induces caspase-1, which in turn induces the processing of inflammatory cytokines such as IL-1β and IL-18. So, to understand inflammasomes regulation becomes crucial to treat several disorders including autoinflammatory diseases. Since green propolis extracts are able to regulate inflammatory pathways, this work purpose was to investigate if this extract could also act on inflammasomes regulation. First, the extract was characterized and it demonstrated the presence of important compounds, especially Artepillin C. This extract was effective in reducing the IL-1β secretion in mouse macrophages and this reduction was correlated with a decrease in activation of the protease caspase-1. Furthermore, we found that the extract at a concentration of 30 μg/mL was not toxic to the cells even after a 18-hour treatment. Altogether, these data indicate that Brazilian green propolis (EPP-AF) extract has a role in regulating the inflammasomes. PMID:23690844

  4. Flacourtosides A-F, phenolic glycosides isolated from Flacourtia ramontchi.

    PubMed

    Bourjot, Mélanie; Leyssen, Pieter; Eydoux, Cécilia; Guillemot, Jean-Claude; Canard, Bruno; Rasoanaivo, Philippe; Guéritte, Françoise; Litaudon, Marc

    2012-04-27

    In an effort to identify novel inhibitors of chikungunya (CHIKV) and dengue (DENV) virus replication, a systematic study with 820 ethyl acetate extracts of madagascan plants was performed in a virus-cell-based assay for CHIKV, and a DENV NS5 RNA-dependent RNA polymerase (RdRp) assay. The extract obtained from the stem bark of Flacourtia ramontchi was selected for its significant activity in both assays. Six new phenolic glycosides, named flacourtosides A-F (1-6), phenolic glycosides itoside H, xylosmin, scolochinenoside D, and poliothrysoside, and betulinic acid 3β-caffeate were obtained using the bioassay-guided isolation process. Their structures were elucidated by comprehensive analyses of NMR spectroscopic and mass spectrometric data. Even though several extracts and fractions showed significant selective antiviral activity in the CHIKV virus-cell-based assay, none of the purified compounds did. However, in the DENV RNA polymerase assay, significant inhibition was observed with betulinic acid 3β-caffeate (IC(50) = 0.85 ± 0.1 μM) and to a lesser extent for the flacourtosides A and E (1 and 5, respectively), and scolochinenoside D (IC(50) values ~10 μM). PMID:22439591

  5. Effects of Solute Nb Atoms and Nb Precipitates on Isothermal Transformation Kinetics from Austenite to Ferrite

    NASA Astrophysics Data System (ADS)

    Wang, Li; Parker, Sally; Rose, Andrew; West, Geoff; Thomson, Rachel

    2016-05-01

    Nb is a very important micro-alloying element in low-carbon steels, for grain size refinement and precipitation strengthening, and even a low content of Nb can result in a significant effect on phase transformation kinetics from austenite to ferrite. Solute Nb atoms and Nb precipitates may have different effects on transformation behaviors, and these effects have not yet been fully characterized. This paper examines in detail the effects of solute Nb atoms and Nb precipitates on isothermal transformation kinetics from austenite to ferrite. The mechanisms of the effects have been analyzed using various microscopy techniques. Many solute Nb atoms were found to be segregated at the austenite/ferrite interface and apply a solute drag effect. It has been found that solute Nb atoms have a retardation effect on ferrite nucleation rate and ferrite grain growth rate. The particle pinning effect caused by Nb precipitates is much weaker than the solute drag effect.

  6. R&D of low activation ferritic steels for fusion in japanese universities*1

    NASA Astrophysics Data System (ADS)

    Kohyama, Akira; Kohno, Yutaka; Asakura, Kentaro; Kayano, Hideo

    1994-09-01

    Following the brief review of the R&D of low activation ferritic steels in Japanese universities, the status of 9Cr-2W type ferritic steels development is presented. The main emphasis is on mechanical property changes by fast neutron irradiation in FFTF. Bend test, tensile test, CVN test and in-reactor creep results are provided including some data about low activation ferritic steels with Cr variation from 2.25 to 12%. The 9Cr-2W ferritic steel, denoted as JLF-1, showed excellent mechanical properties under fast neutron irradiation as high as 60 dpa. As potential materials for DEMO and beyond, innovative oxide dispersion strengthened (ODS) quasi-amorphous low activation ferritic steels are introduced. The baseline properties, microstructural evolution under ion irradiation and the recent progress of new processes are provided.

  7. FERRITE-LINED HOM ABSORBER FOR THE E-COOL ERL

    SciTech Connect

    HAHN,H.

    2007-06-25

    An R&D Energy Recovery Linac (ERL) intended as step towards electron-cooling of RHIC-II is being constructed at this laboratory. The center piece of the project is the experimental 5-cell 703.75 MHz superconducting ECX cavity. Successful operation will depend on effective NOM suppression, and it is planned to achieve NOM damping exclusively with room temperature ferrite absorbers. A ferrite-lined pillbox test model with dimensions reflecting the operational unit was assembled and attached to the 5-cell copper cavity. The cavity resonances of the lowest dipole and monopole modes and their damping due to the ferrite were determined. The effective ferrite properties in a form portable to other structures were obtained from network analyzer measurements of the ferrite absorber models and their interpretation with the simulation code Microwave Studio.

  8. Negative and near zero refraction metamaterials based on permanent magnetic ferrites

    PubMed Central

    Bi, Ke; Guo, Yunsheng; Zhou, Ji; Dong, Guoyan; Zhao, Hongjie; Zhao, Qian; Xiao, Zongqi; Liu, Xiaoming; Lan, Chuwen

    2014-01-01

    Ferrite metamaterials based on the negative permeability of ferromagnetic resonance in ferrites are of great interest. However, such metamaterials face a limitation that the ferromagnetic resonance can only take place while an external magnetic field applied. Here, we demonstrate a metamaterial based on permanent magnetic ferrite which exhibits not only negative refraction but also near zero refraction without applied magnetic field. The wedge-shaped and slab-shaped structures of permanent magnetic ferrite-based metamaterials were prepared and the refraction properties were measured in a near-field scanning system. The negative and near zero refractive behaviors are confirmed by the measured spatial electric field maps. This work offers new opportunities for the development of ferrite-based metamaterials. PMID:24553188

  9. Millimeter wave complementary metal-oxide-semiconductor on-chip hexagonal nano-ferrite circulator

    NASA Astrophysics Data System (ADS)

    Chao, Liu; Oukacha, Hassan; Fu, Enjin; Koomson, Valencia Joyner; Afsar, Mohammed N.

    2015-05-01

    Hexagonal ferrites such as M-type BaFe12O19 and SrFe12O19 have strong uniaxial anisotropic magnetic field and remanent magnetism. The nano-sized ferrite powder exhibits high compatibility and processability in composite material. New magnetic devices using the M-type ferrite materials can work in the tens of GHz frequency range from microwave to millimeter wave without the application of strong external magnetic field. The micro- and nano-sized hexagonal ferrite can be conveniently utilized to fabricate magnetic components integrated in CMOS integrated circuits as thin as several micrometers. The micro-fabrication method of such nano ferrite device is presented in this paper. A circulator working at 60 GHz is designed and integrated into the commercial CMOS process. The circulator exhibits distinct circulation properties in the frequency range from 56 GHz to 58 GHz.

  10. Magnetic properties of Sr-ferrites synthesized in molten (NaCl+KCl) flux

    NASA Astrophysics Data System (ADS)

    Kim, Si-Dong; Kim, Jung-Sik

    2006-12-01

    The Sr-ferrite powders, SrFe12O19, were synthesized by the molten salt method using (NaCl+KCl) mixture. Particle morphology was homogeneous and hexagonal platelet like. Both particle size and thickness increased as the reaction temperature and time increased. The sintering density of Sr-ferrite magnet prepared with powders by the molten salt method showed the maximum value at the sintering temperature of 1200C. The magnetic properties of the Sr-ferrite magnet were investigated with various sintering temperatures. The maximum values of remanent magnetization ( σr, 45 emu/g) and coercivity field ( Hcj, 298 kA/m) occurred at the sintering temperatures of 1150- 1200C. The Sr-ferrite magnet by a molten salt method showed higher remanent magnetization and coercivity field than those of the Sr-ferrite magnet prepared with the same starting materials by a conventional ceramic process.

  11. Negative and near zero refraction metamaterials based on permanent magnetic ferrites.

    PubMed

    Bi, Ke; Guo, Yunsheng; Zhou, Ji; Dong, Guoyan; Zhao, Hongjie; Zhao, Qian; Xiao, Zongqi; Liu, Xiaoming; Lan, Chuwen

    2014-01-01

    Ferrite metamaterials based on the negative permeability of ferromagnetic resonance in ferrites are of great interest. However, such metamaterials face a limitation that the ferromagnetic resonance can only take place while an external magnetic field applied. Here, we demonstrate a metamaterial based on permanent magnetic ferrite which exhibits not only negative refraction but also near zero refraction without applied magnetic field. The wedge-shaped and slab-shaped structures of permanent magnetic ferrite-based metamaterials were prepared and the refraction properties were measured in a near-field scanning system. The negative and near zero refractive behaviors are confirmed by the measured spatial electric field maps. This work offers new opportunities for the development of ferrite-based metamaterials. PMID:24553188

  12. Effect of chemical composition and ferrite content on room temperature SCC behavior of austenitic weld metals

    SciTech Connect

    Raghunatha Rao, B.; Prasad Rao, K.; Iyer, K.J.L. )

    1993-03-01

    Austenitic stainless steels are widely used in the welded condition especially in chemical, petrochemical, thermal power, and nuclear industries where they are subjected to stresses in corrosive environments. Since austenitic stainless steel weld metals invariably contain some delta ferrite to avoid hot cracking, the effect of ferrite on the stress corrosion cracking behavior is important. Austenitic weld metals with different alloy additions and different ferrite contents were investigated for their resistance to room temperature stress corrosion cracking (SCC) in 5 N H[sub 2]SO[sub 4] + 0.5 N NaCl solution. It was found that the delta ferrite content in the weld metals had a predominant effect on the SCC resistance. Higher ferrite contents increased the tendency for SCC. Post-weld heat treatment of weld metals resulted in the improvement of the SCC resistance.

  13. High-frequency dielectric behaviour of erbium substituted Ni-Zn ferrites

    NASA Astrophysics Data System (ADS)

    Kumar, K. Vijaya; Reddy, A. Chandra Shekhar; Ravinder, D.

    2003-07-01

    Dielectric properties such as dielectric constant ( ɛ') and dielectric loss tangent (tan δ) of mixed Ni-Zn-Er ferrites have been measured at room temperature in the frequency range 1-13 MHz using a HP 4192A impedance analyser. Plots of dielectric constant ( ɛ') versus frequency show a normal dielectric behaviour of spinel ferrites. The frequency dependence of dielectric loss tangent (tan δ) is found to be abnormal, giving a peak at certain frequency for all mixed Ni-Zn-Er ferrites. A qualitative explanation is given for the composition and frequency dependence of the dielectric constant and dielectric loss tangent. Plot of dielectric constant versus temperature has shown a transition near the Curie temperature for all the samples of Ni-Zn-Er ferrites. On the basis of these results an explanation for the dielectric mechanism in Ni-Zn-Er ferrites is suggested.

  14. Effects of Solute Nb Atoms and Nb Precipitates on Isothermal Transformation Kinetics from Austenite to Ferrite

    NASA Astrophysics Data System (ADS)

    Wang, Li; Parker, Sally; Rose, Andrew; West, Geoff; Thomson, Rachel

    2016-07-01

    Nb is a very important micro-alloying element in low-carbon steels, for grain size refinement and precipitation strengthening, and even a low content of Nb can result in a significant effect on phase transformation kinetics from austenite to ferrite. Solute Nb atoms and Nb precipitates may have different effects on transformation behaviors, and these effects have not yet been fully characterized. This paper examines in detail the effects of solute Nb atoms and Nb precipitates on isothermal transformation kinetics from austenite to ferrite. The mechanisms of the effects have been analyzed using various microscopy techniques. Many solute Nb atoms were found to be segregated at the austenite/ferrite interface and apply a solute drag effect. It has been found that solute Nb atoms have a retardation effect on ferrite nucleation rate and ferrite grain growth rate. The particle pinning effect caused by Nb precipitates is much weaker than the solute drag effect.

  15. Correlation Between Microstructures and Tensile Properties of Strain-Based API X60 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Kim, Hyoung Seop; Ro, Yunjo; Lee, Chang Sun; Hwang, Byoungchul; Shin, Sang Yong

    2016-03-01

    The correlation between the microstructures and tensile properties of strain-based American Petroleum Institute (API) X60 pipeline steels was investigated. Eight types of strain-based API X60 pipeline steels were fabricated by varying the chemical compositions, such as C, Ni, Cr, and Mo, and the finish cooling temperatures, such as single-phase and dual-phase regions. In the 4N and 5C steels, the volume fractions of bainitic ferrite (BF) and the secondary phases increased with the increasing C and adding Cr instead of Ni. In the 5C and 6NC steels, the volume fractions of acicular ferrite (AF) and BF decreased with increasing C and adding Ni, whereas the volume fractions of polygonal ferrite (PF) and the secondary phases increased. In the 6NC and 6NM steels, the volume fraction of BF was increased by adding Mo instead of Cr, whereas the volume fractions of PF and the secondary phases decreased. In the steels rolled in the single-phase region, the volume fraction of polygonal ferrite ranged from 40 to 60 pct and the volume fraction of AF ranged from 20 to 40 pct. In the steels rolled in the dual-phase region, however, the volume fraction of PF was more than 70 pct and the volume fraction of AF was below 20 pct. The strength of the steels with a high volume fraction of AF was higher than those of the steels with a high volume fraction of PF, whereas the yield point elongation and the strain hardening exponent were opposite. The uniform elongation after the thermal aging process decreased with increasing volume fraction of PF, whereas the uniform elongation increased with increasing volume fraction of AF. The strain hardening exponent increased with increasing volume fraction of PF, but decreased with increasing volume fraction of AF and effective grain size.

  16. Correlation Between Microstructures and Tensile Properties of Strain-Based API X60 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Kim, Hyoung Seop; Ro, Yunjo; Lee, Chang Sun; Hwang, Byoungchul; Shin, Sang Yong

    2016-06-01

    The correlation between the microstructures and tensile properties of strain-based American Petroleum Institute (API) X60 pipeline steels was investigated. Eight types of strain-based API X60 pipeline steels were fabricated by varying the chemical compositions, such as C, Ni, Cr, and Mo, and the finish cooling temperatures, such as single-phase and dual-phase regions. In the 4N and 5C steels, the volume fractions of bainitic ferrite (BF) and the secondary phases increased with the increasing C and adding Cr instead of Ni. In the 5C and 6NC steels, the volume fractions of acicular ferrite (AF) and BF decreased with increasing C and adding Ni, whereas the volume fractions of polygonal ferrite (PF) and the secondary phases increased. In the 6NC and 6NM steels, the volume fraction of BF was increased by adding Mo instead of Cr, whereas the volume fractions of PF and the secondary phases decreased. In the steels rolled in the single-phase region, the volume fraction of polygonal ferrite ranged from 40 to 60 pct and the volume fraction of AF ranged from 20 to 40 pct. In the steels rolled in the dual-phase region, however, the volume fraction of PF was more than 70 pct and the volume fraction of AF was below 20 pct. The strength of the steels with a high volume fraction of AF was higher than those of the steels with a high volume fraction of PF, whereas the yield point elongation and the strain hardening exponent were opposite. The uniform elongation after the thermal aging process decreased with increasing volume fraction of PF, whereas the uniform elongation increased with increasing volume fraction of AF. The strain hardening exponent increased with increasing volume fraction of PF, but decreased with increasing volume fraction of AF and effective grain size.

  17. Development of ferritic steels for fusion reactor applications

    SciTech Connect

    Klueh, R.L.; Maziasz, P.J.; Corwin, W.R.

    1988-08-01

    Chromium-molybdenum ferritic (martensitic) steels are leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment will produce long-lived radioactive isotopes that will lead to difficult waste-disposal problems. Such problems could be reduced by replacing the elements in the steels (i.e., Mo, Nb, Ni, N, and Cu) that lead to long-lived radioactive isotopes. We have proposed the development of ferritic steels analogous to conventional Cr-Mo steels, which contain molybdenum and niobium. It is proposed that molybdenum be replaced by tungsten and niobium be replaced by tantalum. Eight experimental steels were produced. Chromium concentrations of 2.25, 5, 9, and 12% were used (all concentrations are in wt %). Steels with these chromium compositions, each containing 2% W and 0.25% V, were produced. To determine the effect of tungsten and vanadium, 2.25 Cr steels were produced with 2% W and no vanadium and with 0.25% V and O and 1% W. A 9Cr steel containing 2% W, 0.25 V, and 0.07% Ta was also studied. For all alloys, carbon was maintained at 0.1%. Tempering studies on the normalized steels indicated that the tempering behavior of the new Cr-W steels was similar to that of the analogous Cr-Mo steels. Microscopy studies indicated that 2% tungsten was required in the 2.25 Cr steels to produce 100% bainite in 15.9-mm-thick plate during normalization. The 5Cr and 9Cr steels were 100% martensite, but the 12 Cr steel contained about 75% martensite with the balance delta-ferrite. 33 refs., 35 figs., 5 tabs.

  18. Optimization and testing results of Zr-bearing ferritic steels

    SciTech Connect

    Tan, Lizhen; Yang, Ying; Tyburska-Puschel, Beata; Sridharan, K.

    2014-09-01

    The mission of the Nuclear Energy Enabling Technologies (NEET) program is to develop crosscutting technologies for nuclear energy applications. Advanced structural materials with superior performance at elevated temperatures are always desired for nuclear reactors, which can improve reactor economics, safety margins, and design flexibility. They benefit not only new reactors, including advanced light water reactors (LWRs) and fast reactors such as sodium-cooled fast reactor (SFR) that is primarily designed for management of high-level wastes, but also life extension of the existing fleet when component exchange is needed. Developing and utilizing the modern materials science tools (experimental, theoretical, and computational tools) is an important path to more efficient alloy development and process optimization. Ferritic-martensitic (FM) steels are important structural materials for nuclear reactors due to their advantages over other applicable materials like austenitic stainless steels, notably their resistance to void swelling, low thermal expansion coefficients, and higher thermal conductivity. However, traditional FM steels exhibit a noticeable yield strength reduction at elevated temperatures above ~500°C, which limits their applications in advanced nuclear reactors which target operating temperatures at 650°C or higher. Although oxide-dispersion-strengthened (ODS) ferritic steels have shown excellent high-temperature performance, their extremely high cost, limited size and fabricability of products, as well as the great difficulty with welding and joining, have limited or precluded their commercial applications. Zirconium has shown many benefits to Fe-base alloys such as grain refinement, improved phase stability, and reduced radiation-induced segregation. The ultimate goal of this project is, with the aid of computational modeling tools, to accelerate the development of a new generation of Zr-bearing ferritic alloys to be fabricated using conventional

  19. Hot-Pressed Ferrite-Lead Zirconate Titanate Magnetoelectric Composites

    NASA Astrophysics Data System (ADS)

    Devreugd, C. P.; Srinivasan, G.; Micheli, A. L.; Mantese, J. V.

    2004-03-01

    The electromagnetic coupling in magnetostrictive/piezoelectric is mediated by mechanical stress: magnetostriction induced mechanical deformation and piezoelectric effect induced electric fields. Composites studied so far include ferrite-lead zirconate titanate (PZT) and manganite-PZT [1-3]. Bulk or layered composites are usually synthesized by conventional sintering of mixture of powders or laminated thick films. This study is concerned with the fabrication of novel ferromagnetic-ferroelectric bulk and thin film layered composites by hot pressing together with studies on the nature of magnetoelectric interactions. The objective is to obtain defect free samples with good interface coupling. Systems studied includes Ni-Zn, Co-Zn and Co-Ni ferrites that are predicted to show high piezomagnetic and magnetomechanical couplings and PZT. Samples were prepared using aluminum oxide or high temperature alloy dies. Sintering was done at 1300 K at a pressure of 5000-7000 psi. Measurements of transverse and longitudinal ME coefficients are performed at low frequencies (10 Hz-1kHz), and at electromechanical resonance (100-300 kHz). Important results of our studies are follows. (1) Hot-pressed samples show an order of magnitude improvement in ME voltage coefficient compared to samples processed by conventional sintering. The enhancement is attributed to an increase in density, sample resistivity, and interface coupling. (2) The longitudinal coupling is stronger than the transverse effect. (3) There is a significant increase in ME interactions at electromechanical resonance. (4) Samples with Ni-Zn ferrites show the highest ME coefficients. The results are analysed using our model for a bulk composite. - supported by a grant from the National Science Foundation (DMR-0322254) 1. G. Srinivasan, E. T. Rasmussen, J. Gallegos, Yu. I. Bokhan, and V. M. Laletin, Phys. Rev. B, 64, 214408 (2001). 2. G. Srinivasan, E. T. Rasmussen, B. J. Levin, and R. Hayes, Phys. Rev. B 65, 134402 (2002). 3

  20. Size dependence of magnetorheological properties of cobalt ferrite ferrofluid

    SciTech Connect

    Radhika, B.; Sahoo, Rasmita; Srinath, S.

    2015-06-24

    Cobalt Ferrite nanoparticles were synthesized using co-precipitation method at reaction temperatures of 40°C and 80°C. X-Ray diffraction studies confirm cubic phase formation. The average crystallite sizes were found to be ∼30nm and ∼48nm for 40°C sample and 80°C sample respectively. Magnetic properties measured using vibrating sample magnetometer show higher coercivety and magnetization for sample prepared at 80°C. Magnetorheological properties of CoFe2O4 ferrofluids were measured and studied.

  1. R-SQUARE IMPEDANCES OF ERL FERRITE HOM ABSORBER.

    SciTech Connect

    HAHN, H.; BURRILL, A.; CALAGA,R.; KAYRAN, D.; ZHAO, Y.

    2005-07-10

    An R&D facility for an Energy Recovery Linac (ERL) intended as part of an electron-cooling project for RHIC is, being constructed at this laboratory. The center piece of the facility is a 5-cell 703.75 MHz super-conducting RF linac. Successful operation will depend on effective HOM damping. It is planned to achieve HOM damping exclusively with ferrite absorbers. The performance of a prototype absorber was measured by transforming it into a resonant cavity and alternatively by a conventional wire method. The results expressed as a surface or R-square impedance are presented in this paper.

  2. Modeling the austenite decomposition into ferrite and bainite

    NASA Astrophysics Data System (ADS)

    Fazeli, Fateh

    2005-12-01

    Novel advanced high-strength steels such as dual-phase (DP) and transformation induced plasticity (TRIP) steels, are considered as promising materials for new generation of lightweight vehicles. The superior mechanical properties of these steels, compared to classical high strength steels, are associated with their complex microstructures. The desired phase configuration and morphology can only be achieved through well-controlled processing paths with rather tight processing windows. To implement such challenging processing stages into the current industrial facilities a significant amount of development efforts, in terms of mill trials, have to be performed. Alternatively, process models as predictive tools can be employed to aid the process development' and also to design new steel grades. Knowledge-based process models are developed by virtue of the underlying physical phenomena occurring during the industrial processing and are validated with experimental data. The goal of the present work is to develop an integrated microstructure model to adequately describe the kinetics of austenite decomposition into polygonal ferrite and bainite, such that for complex thermal paths simulating those of industrial practice, the final microstructure in advanced high strength steels can reasonably be predicted. This is in particular relevant to hot-rolled DP and TRIP steels, where the intercritical ferrite evolution due to its crucial influence on the onset and kinetics of the subsequent bainite formation, has to be quantified precisely. The calculated fraction, size and spatial carbon distribution of the intercritical austenite are employed as input to characterize adequately the kinetic of the bainite reaction. Pertinent to ferrite formation, a phenomenological, physically-based model was developed on the ground of the mixed-mode approach. The model deals with the growth stage since nucleation site saturation at prior austenite grain boundaries is likely to be attained

  3. A method for reducing encapsulation stress to ferrite pot cores

    SciTech Connect

    Sanchez, R.O.

    1994-08-01

    This paper describes a method of reducing the mechanical stress caused when a ferrite pot core is encapsulated in a rigid epoxy. the stresses are due to the differences of coefficient of thermal expansion between the two materials. A stress relief medium, phenolic micro-balloon-filled, syntactic polysulfide, is molded into the shape of the pot core. The molded polysulfide is bonded to the core prior to encapsulation. The new package design has made a significant difference in the ability to survive temperature cycles.

  4. Electrical and magnetic properties of nano-sized magnesium ferrite

    NASA Astrophysics Data System (ADS)

    T, Smitha; X, Sheena; J, Binu P.; Mohammed, E. M.

    2015-02-01

    Nano-sized magnesium ferrite was synthesized using sol-gel techniques. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. Vibration Sample Magnetometer was used to record the magnetic measurements. XRD analysis reveals the prepared sample is single phasic without any impurity. Particle size calculation shows the average crystallite size of the sample is 19nm. FTIR analysis confirmed spinel structure of the prepared samples. Magnetic measurement study shows that the sample is ferromagnetic with high degree of isotropy. Hysterisis loop was traced at temperatures 100K and 300K. DC electrical resistivity measurements show semiconducting nature of the sample.

  5. High Temperature Fracture Characteristics of a Nanostructured Ferritic Alloy (NFA)

    SciTech Connect

    Byun, Thak Sang; Kim, Jeoung H; Ji Hyun, Yoon; Hoelzer, David T

    2010-01-01

    High temperature fracture behavior has been investigated for the nanostructured ferritic alloy 14YWT (SM10). The fracture toughness of the alloy was above 140 MPa m at low temperatures, room temperature (RT) and 200 C, but decreased to a low fracture toughness range of 52 82 MPa m at higher temperatures up to 700 C. This behavior was explained by the fractography results indicating that the unique nanostructure of 14YWT alloy produced shallow plasticity layers at high temperatures and a low-ductility grain boundary debonding occurred at 700 C.

  6. Size dependence of magnetorheological properties of cobalt ferrite ferrofluid

    NASA Astrophysics Data System (ADS)

    Radhika, B.; Sahoo, Rasmita; Srinath, S.

    2015-06-01

    Cobalt Ferrite nanoparticles were synthesized using co-precipitation method at reaction temperatures of 40°C and 80°C. X-Ray diffraction studies confirm cubic phase formation. The average crystallite sizes were found to be ˜30nm and ˜48nm for 40°C sample and 80°C sample respectively. Magnetic properties measured using vibrating sample magnetometer show higher coercivety and magnetization for sample prepared at 80°C. Magnetorheological properties of CoFe2O4 ferrofluids were measured and studied.

  7. Complex electric modulus and dielectric relaxation of nanocrystalline zinc ferrite

    NASA Astrophysics Data System (ADS)

    Choudhury, S.; Sinha, M.; Mandal, M. K.; Pradhan, S. K.; Meikap, A. K.

    2015-06-01

    We report the complex electric modulus and dielectric relaxation studies of nanocrystalline zinc ferrite. The dielectric constant exhibits strong temperature dependence at higher temperature and lower frequencies and this has been analyzed in terms of electric modulus vector. The real part of complex impedance has also been modeled by an ideal equivalent circuit consisting of grain and grain boundary resistances and capacitances. The metallic electrode and semiconductor junction forms Schottky diode, whose parameters like built in voltage and space charge density have been extracted from the capacitance-voltage characteristics.

  8. SELECTIVE SEPARATION OF URANIUM FROM FERRITIC STAINLESS STEELS

    DOEpatents

    Beaver, R.J.; Cherubini, J.H.

    1963-05-14

    A process is described for separating uranium from a nuclear fuel element comprising a uranium-containing core and a ferritic stainless steel clad by heating said element in a non-carburizing atmosphere at a temperature in the range 850-1050 un. Concent 85% C, rapidly cooling the heated element through the temperature range 815 un. Concent 85% to 650 EC to avoid annealing said steel, and then contacting the cooled element with an aqueous solution of nitric acid to selectively dissolve the uranium. (AEC)

  9. Corrosion Performance of Ferritic Steel for SOFC Interconnect Applications

    SciTech Connect

    Ziomek-Moroz, M.; Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Jablonski, P.D.; Alman, D.E.

    2006-11-01

    Ferritic stainless steels have been identified as potential candidates for interconnects in planar-type solid oxide fuel cells (SOFC) operating below 800ºC. Crofer 22 APU was selected for this study. It was studied under simulated SOFC-interconnect dual environment conditions with humidified air on one side of the sample and humidified hydrogen on the other side at 750ºC. The surfaces of the oxidized samples were studied by scanning electron microscopy (SEM) equipped with microanalytical capabilities. X-ray diffraction (XRD) analysis was also used in this study.

  10. In situ fabrication and characterization of cobalt ferrite nanorods/graphene composites

    SciTech Connect

    Fu, Min; Jiao, Qingze; Zhao, Yun

    2013-12-15

    Cobalt ferrite nanorods/graphene composites were prepared by a one-step hydrothermal process using NaHSO{sub 3} as the reducing agent and 1-propyl-3-hexadecylimidazolium bromide as the structure growth-directing template. The reduction of graphene oxide and the in situ formation of cobalt ferrite nanorods were accomplished in a one-step reaction. The structure and morphology of as-obtained composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, atomic force microscope, X-ray diffractometer, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and Raman spectroscopy. Uniform rod-like cobalt ferrites with diameters of about 100 nm and length of about 800 nm were homogeneously distributed on the graphene sheets. The hybrid materials showed a saturation magnetization of 42.5 emu/g and coercivity of 495.1 Oe at room temperature. The electromagnetic parameters were measured using a vector network analyzer. A minimum reflection loss (RL) of − 25.8 dB was observed at 16.1 GHz for the cobalt ferrite nanorods/graphene composites with a thickness of 2 mm, and the effective absorption frequency (RL < − 10 dB) ranged from 13.5 to 18.0 GHz. The composites exhibited better absorbing properties than the cobalt ferrite nanorods and the mixture of cobalt ferrite nanorods and graphene. - Highlights: • Reduction of GO and formation of ferrites were accomplished in a one-step reaction. • Ionic liquid was used to control 1D growth of ferrite nanorods for the first time. • Cobalt ferrite nanorods/graphene composites showed dielectric and magnetic loss. • Cobalt ferrite nanorods/graphene composites exhibited better absorbing properties.

  11. Exchange coupling between soft magnetic ferrite and hard ferromagnetic Sm2Fe17N3 in ferrite/Sm2Fe17N3 composites

    NASA Astrophysics Data System (ADS)

    Imaoka, N.; Kakimoto, E.; Takagi, K.; Ozaki, K.; Tada, M.; Nakagawa, T.; Abe, M.

    2016-05-01

    In our previous work, we succeeded in fabricating ferrite/Sm2Fe17N3 composite magnets from explosive-consolidating Sm2Fe17N3 powders (2μm size) which were coated with a continuous iron ferrite layer (50nm thick) in an aqueous solution. The magnetization curves had no inflection, which suggests that the soft magnetic ferrite layer is exchange-coupled with the hard ferromagnetic Sm2Fe17N3 particles. In this paper, we provide evidence of exchange coupling in ferrite/Sm2Fe17N3 composites by the following means: 1) measurements of recoil permeability, 2) detailed microstructural observation and 3) calculations of the reduction in remanence due to the introduction of a ferrite layer in the Sm2Fe17N3 magnets. Our ferrite/Sm2Fe17N3 composite magnets are a novel type of spring magnet in which an insulating soft magnetic phase is exchange-coupled with hard magnetic phase.

  12. Addition of MgO Nanoparticles to Carbon Structural Steel and the Effect on Inclusion Characteristics and Microstructure

    NASA Astrophysics Data System (ADS)

    Gao, Xiangzhou; Yang, Shufeng; Li, Jingshe; Liao, Hang; Gao, Wei; Wu, Tuo

    2016-04-01

    An innovative approach for pre-dispersing MgO nanoparticles with AlSi alloy nanoparticles was established, and the nanoparticles were dispersed well in carbon structural steel. After adding different mass fractions of MgO nanoparticles in steel, the majority of inclusions contained MgO·Al2O3 spinel and MgO-Al2O3-bearing hybrid inclusion, and these inclusions promoted acicular ferrite (AF) formation. With increasing amount of added nanoparticles, the average inclusion size increased from 0.90 to 1.50 μm and the inclusion size was considerably refined, but the ability of inclusions to induce AF was greatly declined. It was revealed that the inclusion size was the decisive factor influencing the inducing ability of inclusions for AF, which also got a solid support from the nucleation thermomechanical and dynamic analyses. When the mass fraction of MgO nanoparticles reached 0.05 pct, the proportion of AF in microstructure is relatively larger and the degree of interlocking of the AF within the microstructure was optimized. The ferrite grains also got refined and the average grain size decreased by more than 94 pct compared with that of the original steel.

  13. Effects of Ultra Fast Cooling on Microstructure and Mechanical Properties of Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Tian, Yong; Li, Qun; Wang, Zhao-dong; Wang, Guo-dong

    2015-09-01

    X70 (steel A) and X80 (steel B) pipeline steels were fabricated by ultra fast cooling (UFC). UFC processing improves not only ultimate tensile strength (UTS), yield strength (YS), yield ratio (YS/UTS), and total elongation of both steels, but also their Charpy absorbed energy ( A K) as well. The microstructures of both steels were all composed of quasi polygonal, acicular ferrite (AF), and granular bainite. MA islands (the mixtures of brittle martensite and residual austenite) are more finely dispersed in steel B, and the amount of AF in steel B is much more than that in steel A. The strength of steel B is higher than that of steel A. This is mainly attributed to the effect of the ferrite grain refinement which is resulted from UFC processing. The finely dispersed MA islands not only provide dispersion strengthening, but also reduce loss of impact properties to pipeline steels. UFC produces low-temperature transformation microstructures containing larger amounts of AFs. The presence of AF is a crucial factor in achieving desired mechanical properties for both steels. It is suggested that the toughness of the experimental steel increases with increasing the amount of AF.

  14. Relations between magneto-optical properties and reactivity in cobalt-manganese ferrite thin films and powders

    NASA Astrophysics Data System (ADS)

    Bouet, Laurence; Tailhades, Philippe; Rousset, Abel

    1996-02-01

    Co-Mn spinel ferrites were prepared as submicron powders and thin films. Because of their finely divided state, these spinels could be oxidized at low temperatures to give novel cation-deficient ferrites. For these two material forms, the magneto-optical properties were found to be strongly dependent on the ferrite oxidation state. The highest coercivities and Faraday rotations were obtained when the ferrites were partially oxidized. These phenomena are attributed to the mechanical stress effect developed during the oxidation of the manganese ions. The properties of these ferrites could be of interest for magneto-optical recording applications. The first static recording tests were performed at 780 nm wavelength.

  15. Totally thorascopic surgical ablation of persistent AF and long-standing persistent atrial fibrillation using the "Dallas" lesion set.

    PubMed

    Edgerton, James R; Jackman, Warren M; Mahoney, Cecile; Mack, Michael J

    2009-12-01

    Minimally invasive surgery consisting of bipolar radiofrequency pulmonary vein (PV) isolation and limited ganglionated plexus ablation is effective in eliminating atrial fibrillation (AF) in patients with paroxysmal AF but is less effective in those with persistent AF or long-standing persistent AF. The purpose of this study was examine the results of minimally invasive surgery incorporating an additional set of radiofrequency ablation lines replicating a left-sided Cox maze III procedure. Thirty patients with persistent AF (n = 10) or long-standing persistent AF (n = 20) underwent minimally invasive surgery with an extended lesion set and PV isolation for a minimum follow-up of 6 months. Linear lesions were created at the roof line, at the anterior line, and between the roof line and the left atrial appendage. All patients underwent limited ganglionated plexus ablation and left atrial appendage excision as well as PV isolation verification. Block across the roof and anterior lines was confirmed in 29 (96.6%) of the 30 patients. Follow-up included 2-week event monitoring with auto-trigger in 21 patients, pacemaker interrogation in 8, and ECG in 1 who was in AF and refused longer-term monitoring. No operative mortality or major morbidity occurred. At 6 months, 24 (80%) of the 30 patients were free of AF: 15 (75%) with long-standing persistent AF and 9 (90%) with persistent AF. Among the six failures, burden of AF was low: one had 1 episode >15 seconds, two had 4 episodes, one had 6 episodes, one had >50 episodes, and one had AF on ECG and refused further monitoring. Early results of minimally invasive surgery with a new extended linear lesion set suggest increased efficacy over PV isolation and limited ganglionated plexus ablation in patients with persistent AF or long-standing persistent AF. PMID:19959146

  16. Surface chemistry, friction and wear of Ni-Zn and Mn-Zn ferrites in contact with metals

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    X-ray photoelectron and Auger electron spectroscopy analysis were used in sliding friction experiments. These experiments were conducted with hot-pressed polycrystalline Ni-Zn and Mn-Zn ferrites, and single-crystal Mn-Zn ferrite in contact with various transition metals at room temperature in both vacuum and argon. The results indicate that Ni2O3 and Fe3O4 were present on the Ni-Zn ferrite surface in addition to the nominal bulk constituents, while MnO2 and Fe3O4 were present on the Mn-Zn ferrite surface in addition to the nominal bulk constituents. The coefficients of friction for the ferrites in contact with metals were related to the relative chemical activity of these metals. The more active the metal, the higher is the coefficient of friction. The coefficients of friction for the ferrites were correlated with the free energy of formation of the lowest metal oxide. The interfacial bond can be regarded as a chemical bond between the metal atoms and the oxygen anions in the ferrite surfaces. The adsorption of oxygen on clean metal and ferrite does strengthen the metal-ferrite contact and increase the friction. The ferrites exhibit local cracking and fracture with sliding under adhesive conditions. All the metals transferred to he surfaces of the ferrites in sliding.

  17. Synthesis and Characterization of Zirconium Substituted Cobalt Ferrite Nanopowders

    DOE PAGESBeta

    Rus, S. F.; Vlazan, P.; Herklotz, A.

    2016-01-01

    Nanocrystalline ferrites; CoFe2O4 (CFO) and CoFe1.9Zr0.1O4 (CFZO) have been synthesized through chemical coprecipitation method. Moreover, the role played by the zirconium ions in improving the magnetic and structural properties is analyzed. X-ray diffraction revealed a single-phase cubic spinel structure for both materials, where the crystallite size increases and the lattice parameter decreases with substitution of Zr. The average sizes of the nanoparticles are estimated to be 16-19 nm. These sizes are small enough to achieve the suitable signal to noise ratio in the high density recording media. An increase in the saturation magnetization with the substitution of Zr suggests themore » preferential occupation of Zr4+ ions in the tetrahedral sites. A decrease in the coercivity values indicates the reduction of magneto-crystalline anisotropy. We investigated spinel ferrites can be used also in recoding media due to the large value of coercivity 1000 Oe which is comparable to those of hard magnetic materials.« less

  18. Synthesis and Characterization of Zirconium Substituted Cobalt Ferrite Nanopowders

    SciTech Connect

    Rus, S. F.; Vlazan, P.; Herklotz, A.

    2016-01-01

    Nanocrystalline ferrites; CoFe2O4 (CFO) and CoFe1.9Zr0.1O4 (CFZO) have been synthesized through chemical coprecipitation method. Moreover, the role played by the zirconium ions in improving the magnetic and structural properties is analyzed. X-ray diffraction revealed a single-phase cubic spinel structure for both materials, where the crystallite size increases and the lattice parameter decreases with substitution of Zr. The average sizes of the nanoparticles are estimated to be 16-19 nm. These sizes are small enough to achieve the suitable signal to noise ratio in the high density recording media. An increase in the saturation magnetization with the substitution of Zr suggests the preferential occupation of Zr4+ ions in the tetrahedral sites. A decrease in the coercivity values indicates the reduction of magneto-crystalline anisotropy. We investigated spinel ferrites can be used also in recoding media due to the large value of coercivity 1000 Oe which is comparable to those of hard magnetic materials.

  19. An analytical model of eddy current ferrite-core probes

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Bowler, J. R.

    2012-05-01

    An analytical model of an axisymmetric eddy current probe with a cylindrical ferrite core above a layered conductive half-space is developed. Initially we consider the magnetic vector potential of a circular filament coaxial with a ferrite core over a layered conducting half-space. The principle of superposition is then used to derive close-form expressions for both the electromagnetic field and the impedance of a coil from the filament field. Rather than locating the probe in infinite space, it is confined coaxially within a circularly cylindrical boundary on which the vector potential field is zero. The radius of this artificial boundary is large in order to ensure that does not interfere substantially with the field near the probe. By using a truncated region in this way, the vector potential in the probe region can be expanded as a series rather than an integral form. Thus the solution of the problem amounts to finding the expansion coeefficients in the series. The numerical predictions of probe impedance have been compared with experimental data showing good agreement.

  20. Structural and magnetic properties of chromium doped zinc ferrite

    SciTech Connect

    Sebastian, Rintu Mary; Thankachan, Smitha; Xavier, Sheena; Mohammed, E. M.; Joseph, Shaji

    2014-01-28

    Zinc chromium ferrites with chemical formula ZnCr{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were prepared by Sol - Gel technique. The structural as well as magnetic properties of the synthesized samples have been studied and reported here. The structural characterizations of the samples were analyzed by using X – Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The single phase spinel cubic structure of all the prepared samples was tested by XRD and FTIR. The particle size was observed to decrease from 18.636 nm to 6.125 nm by chromium doping and induced a tensile strain in all the zinc chromium mixed ferrites. The magnetic properties of few samples (x = 0.0, 0.4, 1.0) were investigated using Vibrating Sample Magnetometer (VSM)

  1. Stability tests of permanent magnets built with strontium ferrite

    SciTech Connect

    Glass, H.D.; Brown, B.C.; Foster, G.W.; Fowler, W.B.; Gustafson, R.; Jackson, G.P.; Ostiguy, J.F.; Volk, J.T.

    1997-06-01

    Permanent magnets built using strontium ferrite bricks have been tested for stability against demagnetization. Ten test dipoles were built to monitor ferrite behavior under a variety of stressing conditions, including irradiation, mechanical shock, extreme thermal excursions, and long term magnetization stability. The test magnets were geometrically similar to, but much shorter than, the magnets built for the 8 GeV transfer line at FNAL. No loss of magnetization was observed for bricks exposed to a proton beam, and a magnet exposed to several Gigarads of Co{sup 60} gamma radiation suffered no measurable demagnetization. The magnet strength was observed to decrease logarithmically with time, consistent with the expected effect of thermal fluctuations. Irreversible demagnetization of {approx}0.1% was seen in cooling magnets to 0{degree}C, and the loss was {approx}0.2% for magnets cooled to -20{degree}C. No additional demagnetization was seen on subsequent cycling to 0{degree}C. Finally, one of the long dipoles built for the 8 GeV line was periodically tested over the course of 3 months, and showed no measurable demagnetization.

  2. Anticorrosion Properties of Pigments based on Ferrite Coated Zinc Particles

    NASA Astrophysics Data System (ADS)

    Benda, P.; Kalendová, A.

    The paper deals with a new anticorrosion pigment, synthesized on a core-shell basis. For its syntheses a starting substance is used that forms the lamellar shaped core; namely lamellar zinc. The cover of the core is represented by zinc oxide, which is in fact partly oxidized lamellar zinc core, and is created during the calcination of the pigment. The compound that forms the top layer of the core, a ferrite, is also formed during calcination. The formula for the prepared pigment is then defined as MexZn1-xFe2O4/Zn and the formula of thin ferrite layer is MexZn1-xFe2O4 (where Me = Ca, Mg). Due to its shape, this anticorrosion pigment includes another anticorrosion effect, the so called "barrier effect". The mechanisms of anticorrosion effect, corrosion efficiency and mechanical properties were investigated for epoxy-ester paint systems with 10%pigment volume concentration (PVC). Mechanical tests were performed to determine the adhesiveness and mechanical resistance of paints and accelerated corrosion tests were carried out to evaluate efficiency against chemical degradation factors.

  3. Oriented attachment explains cobalt ferrite nanoparticle growth in bioinspired syntheses.

    PubMed

    Wolff, Annalena; Hetaba, Walid; Wißbrock, Marco; Löffler, Stefan; Mill, Nadine; Eckstädt, Katrin; Dreyer, Axel; Ennen, Inga; Sewald, Norbert; Schattschneider, Peter; Hütten, Andreas

    2014-01-01

    Oriented attachment has created a great debate about the description of crystal growth throughout the last decade. This aggregation-based model has successfully described biomineralization processes as well as forms of inorganic crystal growth, which could not be explained by classical crystal growth theory. Understanding the nanoparticle growth is essential since physical properties, such as the magnetic behavior, are highly dependent on the microstructure, morphology and composition of the inorganic crystals. In this work, the underlying nanoparticle growth of cobalt ferrite nanoparticles in a bioinspired synthesis was studied. Bioinspired syntheses have sparked great interest in recent years due to their ability to influence and alter inorganic crystal growth and therefore tailor properties of nanoparticles. In this synthesis, a short synthetic version of the protein MMS6, involved in nanoparticle formation within magnetotactic bacteria, was used to alter the growth of cobalt ferrite. We demonstrate that the bioinspired nanoparticle growth can be described by the oriented attachment model. The intermediate stages proposed in the theoretical model, including primary-building-block-like substructures as well as mesocrystal-like structures, were observed in HRTEM measurements. These structures display regions of substantial orientation and possess the same shape and size as the resulting discs. An increase in orientation with time was observed in electron diffraction measurements. The change of particle diameter with time agrees with the recently proposed kinetic model for oriented attachment. PMID:24605288

  4. Low-chromium reduced-activation ferritic steels for fusion

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.; Kenik, E.A.

    1996-04-01

    Development of reduced-activation ferritic steels has concentrated on high-chromium (8-10 wt% Cr) steels. However, there are advantages for a low-chromium steel, and initial ORNL studies on reduced-activation steels were on compositions with 2.25 to 12% Cr. Those studies showed an Fe-2.25Cr-2W-0.25V-0.1C (2 1/4Cr-2WV) steel to have the highest strenglth of the steels studied. Although this steel had the best strength, Charpy impact properties were inferior to those of an Fe-9Cr-2W-0.25V-0.07Ta-0.1C (9Cr-2WVTa) and an Fe-2.25Cr-2W-0.1C (2 1/4Cr-2W) steel. Therefore, further development of the low-chromium Cr-W steels was required. These results indicate that it is possible to develop low-chromium reduced-activation ferritic steels that have tensile and impact properties as good or better than those of high-chromium (7-9% Cr) steels. Further improvement of properties should be possible by optimizing the composition.

  5. Magnetic Contribution to heat capacity and entropy of nickel ferrite

    SciTech Connect

    Ziemniak, S. E.; Anovitz, Lawrence {Larry} M; Castelli, R. A.; Porter, Wallace D

    2006-01-01

    The heat capacity of nickel ferrite was measured as a function of temperature from 50 to 1200 C using a differential scanning calorimeter. A thermal anomaly was observed at 584.9 C, the expected Curie temperature, TC. The observed behavior was interpreted by recognizing the sum of three contributions: (1) lattice (vibrational), (2) a spin wave (magnetic) component and (3) a ?-transition (antiferromagnetic-paramagnetic transition) at the Curie temperature. The first was modeled using vibrational frequencies derived from an experimentally-based IR absorption spectrum, while the second was modeled using a spin wave analysis that provided a T3/2 dependency in the low-temperature limit, but incorporated an exchange interaction between cation spins in the octahedral and tetrahedral sites at elevated temperatures, as first suggested by Grimes [15]. The ?-transition was fitted to an Inden-type model which consisted of two truncated power law series in dimensionless temperature (T/TC). Exponential equality (m=n=7) was observed below and above TC, indicating symmetry about the Curie temperature. Application of the methodology to existing heat capacity data for other transition metal ferrites (AFe2O4, A=Fe, Co) revealed nearly the same exponential equality, i.e., m=n=5.

  6. Study of dielectric and impedance properties of Mn ferrites

    NASA Astrophysics Data System (ADS)

    Mujasam Batoo, Khalid

    2011-02-01

    The paper reports on the effect of Al substitution on the structural and electrical properties of bulk ferrite series of basic composition MnFe 2-2 xAl 2 xO 4 (0.0≤ x≤0.5) synthesized using solid state reaction method. XRD analysis confirms that all the samples exhibit single phase cubic spinel structure excluding presence of any secondary phase. The dielectric constant shows a normal behaviour with frequency, whereas the loss tangent exhibits an anomalous behaviour with frequency for all compositions. Variation of dielectric properties and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type of interfacial polarization in general and hopping of charge between Fe +2 and Fe +3 as well as between Mn +2 and Mn +3 ions at octahedral sites. The complex impedance plane spectra shows the presence of two semicircles up to x=0.2, and only one semicircle for the higher values of x. The analysis of the data shows that the resistive and capacitive properties of the Mn ferrite are mainly due to processes associated with grain and grain boundaries.

  7. Preparation and Characterization of Zinc-Containing Nickel Gallate Ferrite

    NASA Astrophysics Data System (ADS)

    Hashhash, A.; Imam, N. G.; Ismail, S. M.; Yehia, M.

    2015-10-01

    Polycrystalline Ni1- x Zn x FeGaO4 samples containing different amounts of zinc ( x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized by solid-state reaction. Study of the crystal structure by x-ray diffraction (XRD) revealed peaks typical of a single-phase polycrystalline face-centered cubic structure (FCC). Elemental composition was determined by x-ray fluorescence (XRF) analysis. Fourier-transform infrared (FTIR) spectra contained two absorption bands related to the tetrahedral A and octahedral B sites of the spinel ferrite. Magnetization loops obtained by vibrating sample magnetometry (VSM) indicated that the saturation magnetization, M s, decreased gradually with increasing in Zn content ( x), and that coercivity H c was related to the microstructure of the Zn-doped samples. Mössbauer effect (ME) spectra of the samples were broad and magnetically split for x = 0.0 and 0.1 and quadruple doublets for the other Zn2+ concentrations. The dielectric constant ( ɛ') and dielectric loss tangent (tan δ) were also measured over wide ranges of frequency and temperature by use of the two probe method. The results were explained on the basis of cation-anion-cation and cation-cation interactions through the metal sites in the Ni-Zn-Ga ferrites.

  8. The conduction mechanism of Cu-Ge ferrite

    NASA Astrophysics Data System (ADS)

    Mazen, S. A.; El Taher, A. M.

    2010-09-01

    The electric conductivity, σ (DC and AC), drift mobility and dielectric properties of germanium-substituted copper ferrite, with the chemical formula CuGeFeO (where x=0.0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3), have been studied. Plots of lnσT versus 104/T (K) are linear and showed two sloping regions for all values of x except for the values 0.0 and 0.05, which showed one slope only. The two activation energies around a kink point called Tk were calculated. The electrical conduction in these ferrites is explained on the basis of the hopping mechanism. The values of the charge carrier mobility have been calculated from the experimental values of electrical conductivity which increased exponentially with increasing temperature. Dielectric properties such as dielectric loss tangent tanδ were measured at elevated temperature in the frequency range from 10 2 to 10 6 Hz. The variation of these parameters with temperature is explained qualitatively. An attempt is made to explain the possible mechanism.

  9. A micro-alloyed ferritic steel strengthened by nanoscale precipitates

    SciTech Connect

    Shen, Yongfeng; Wang, Chong M.; Sun, Xin

    2011-10-25

    A ferritic steel with finely dispersive precipitates was investigated to reveal the fundamental strengthening mechanisms. The steel has a yield strength of 760 MPa, approximately three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels, and its ultimate tensile strength reaches 850 MPa with an elongation-to-failure value of 18%. Using energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM), fine carbides TiC with an average diameter of 10 nm were observed in the ferrite matrix of the 0.08%Ti steel, and some cubic M23C6 precipitates were also observed at the grain boundaries and the interior of the grains. The finely dispersive TiC precipitates in the matrix provide matrix strengthening. The estimated magnitude of precipitation strengthening is around 458 MPa, depending on the average size of the nanoscale precipitates. Dislocation densities increased from 3.42×1013 m-2 to 1.69 × 1014 m-2, respectively, with increasing tensile strain from 5.5% to 22%. The measured work-hardening behavior can be related to the observed dislocation accumulations resulting from the dispersive nano-scale precipitates.

  10. Synthesis and Characterization of Zirconium Substituted Cobalt Ferrite Nanopowders.

    PubMed

    Rus, S F; Vlazan, P; Herklotz, A

    2016-01-01

    Nanocrystalline ferrites; CoFe₂O₄ (CFO) and CoFe₁.₉Zr₀.₁O₄ (CFZO) have been synthesized through chemical coprecipitation method. The role played by the zirconium ions in improving the magnetic and structural properties is analyzed. X-ray diffraction revealed a single-phase cubic spinel structure for both materials, where the crystallite size increases and the lattice parameter decreases with substitution of Zr. The average sizes of the nanoparticles are estimated to be 16-19 nm. These sizes are small enough to achieve the suitable signal to noise ratio in the high density recording media. The increase in the saturation magnetization with the substitution of Zr suggests the preferential occupation of Zr⁴⁺ ions in the tetrahedral sites. A decrease in the coercivity values indicates the reduction of magneto-crystalline anisotropy. In the present study the investigated spinel ferrites can be used also in recoding media due to the large value of coercivity 1000 Oe which is comparable to those of hard magnetic materials. PMID:27398535

  11. Anaerobic treatment of strong sewage by a two stage system of AF and UASB reactors.

    PubMed

    Sawajneh, Z; Al-Omari, A; Halalsheh, M

    2010-01-01

    An anaerobic treatment system that consists of an Anaerobic Filter (AF) and an Upflow Anaerobic Sludge Blanket (UASB) in series was built and operated to investigate its performance in treating strong domestic wastewater with high suspended solids fraction under Jordan's ambient temperatures of 25 degrees C for summer and 18 degrees C for winter. The system was operated from September 2003 until early April 2004. The system was operated at a Hydraulic Retention Time (HRT) of 4 hours for the first stage AF and 8 hours for the second stage UASB. Average COD(t) and COD(ss) removal efficiencies of the AF/UASB were 58% and 81% respectively for the operation period. The results showed that the first stage AF was effective in removing suspended solids. In addition, hydrolysis, acidification and methanogenesis took place in the first stage AF which was advantageous to the second stage UASB. It was concluded that the AF/UASB system is effective in treating strong domestic wastewater with high suspended solids content under Jordan's ambient temperatures. PMID:20418638

  12. PUF60: a novel U2AF65-related splicing activity.

    PubMed Central

    Page-McCaw, P S; Amonlirdviman, K; Sharp, P A

    1999-01-01

    We have identified a new pyrimidine-tract binding factor, PUF, that is required, together with U2AF, for efficient reconstitution of RNA splicing in vitro. The activity has been purified and consists of two proteins, PUF60 and the previously described splicing factor p54. p54 and PUF60 form a stable complex in vitro when cotranslated in a reaction mixture. PUF activity, in conjunction with U2AF, facilitates the association of U2 snRNP with the pre-mRNA. This reaction is dependent upon the presence of the large subunit of U2AF, U2AF65, but not the small subunit U2AF35. PUF60 is homologous to both U2AF65 and the yeast splicing factor Mud2p. The C-terminal domain of PUF60, the PUMP domain, is distantly related to the RNA-recognition motif domain, and is probably important in protein-protein interactions. PMID:10606266

  13. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    PubMed

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. PMID:27372134

  14. Influence of particle size on the magnetic spectrum of NiCuZn ferrites for electromagnetic shielding applications

    NASA Astrophysics Data System (ADS)

    Wu, Xiaohan; Yan, Shuoqing; Liu, Weihu; Feng, Zekun; Chen, Yajie; Harris, Vincent G.

    2016-03-01

    The effect of ferrite particle size on the magnetic spectra (1 MHz to 1 GHz) of NiCuZn polycrystalline ferrites doped with Co2O3 and Bi2O3 were systematically investigated. The experiments indicate that the ferrite particle size tailored by grinding time and corresponding sintering temperatures is crucial to achieving high permeability, high Q-factor and low magnetic loss, at 13.56 MHz for electromagnetic shielding applications especially in the near field communication (NFC) field. It is evident that high-performance NiZnCu ferrite materials are strongly tailored by morphology and microstructure. It is conclusive that fine ferrite particles and relatively low sintering temperatures are favorable to lowering magnetic loss and enhancing permeability. This work has built a foundation for improvement of the ferrite slurry used for fabrication of large area tape-casting ferrite sheets.

  15. Effect of O-vacancies on magnetic properties of bismuth ferrite nanoparticles by solution evaporation method

    NASA Astrophysics Data System (ADS)

    Afzal, A. M.; Umair, M.; Dastgeer, G.; Rizwan, M.; Yaqoob, M. Z.; Rashid, R.; Munir, H. S.

    2016-02-01

    Bismuth ferrite is a multiferroic material which shows high magnetization and polarization at room temperature. In present work, the effect of Oxygen (O) vacancies on magnetic properties of bismuth ferrite nanoparticles is studied. Bismuth ferrite nanoparticles (BiFeO3) were synthesized by solution evaporation method (SEM) at room temperature. The sample was annealed under two different atmospheres such as in air and oxygen, to check the effect of O-vacancies on magnetic properties. The average crystallite size of Bismuth ferrite nanoparticles (NPs) as calculated by X-ray diffraction (XRD) falls in the range of 23-32 nm and 26-39 nm for the case of air and oxygen respectively. The crystallite size of bismuth ferrite nanoparticles increases as the temperature was varied from 450 °C to 650 °C. Further the influence of annealing temperature on the magnetic properties of the bismuth ferrite nanoparticles was also observed. It was concluded that the magnetic properties of Bismuth ferrite nanoparticles are directly interconnected to annealing atmosphere and annealing temperature. The magnetic properties were increased in the case of oxygen annealing, which actually leads in our case to an improvement of the crystallinity.

  16. Development of Bimodal Ferrite-Grain Structures in Low-Carbon Steel Using Rapid Intercritical Annealing

    NASA Astrophysics Data System (ADS)

    Karmakar, A.; Karani, A.; Patra, S.; Chakrabarti, Debalay

    2013-05-01

    Mixed ferrite grain structures, which have fine- and coarse-grain regions and showing "bimodal" grain size distributions, have been produced by rapid intercritical annealing of warm-rolled (or cold-rolled) samples. Microstructural changes have been analyzed using dilatometric studies, size prediction of transformed and recrystallized grains, and microtexture measurements. Fine austenite grains (<5 μm) developed during rapid annealing and transformed into fine-ferrite grains (2 to 4 μm) after cooling. Coarse-ferrite grains (28 to 42 μm) resulted from the recrystallization and growth of deformed ferrite. The effect of heating rate on microstructural morphologies during intercritical annealing has also been studied. A slow rate of heating (30 K/s) developed a uniform distribution of fine-ferrite grains and austenitic islands, while rapid heating (300 K/s) generated coarse blocks of austenite, elongated along the prior-pearlitic regions, in the ferrite matrix. As expected, bimodal ferrite grain structures or fine-scale dual-phase structures showed superior combination of tensile strength and ductility, compared to the ultrafine-grained steels.

  17. Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Debnath, A.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

    2016-05-01

    Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl3) and Calcium chloride dihydrate (CaCl2.2H2O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

  18. Effect of filler loading of nickel zinc ferrite on the tensile properties of PLA nanocomposites

    NASA Astrophysics Data System (ADS)

    Shahdan, Dalila; Ahmad, Sahrim Hj

    2013-05-01

    The mechanical strength of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90:10. The MPNC were prepared at constant mixing temperature at 180°C, mixing time of 15 min. and mixing speed of 100 rpm. In order to achieve a good dispersion of NiZn ferrite in the matrix, firstly an ultrasonic treatment had been employed to mix the LNR and NiZn ferrite for 1 hour. The MPNC of PLA/LNR/NiZn ferrite then were prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1-5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases the tensile strength also increases until an optimum value of filler loading was reached. The Young's modulus, tensile strength and elongation at break have also increased. The study proves that NiZn ferrite is excellent reinforcement filler in PLA matrix. Scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX) were meant to show the homogeneity dispersion of nanoparticles within the matrix and to confirm the elemental composition of NiZn ferrites-PLA/LNR nanocomposites respectively.

  19. Heat treatment effects on microstructure and magnetic properties of Mn-Zn ferrite powders

    NASA Astrophysics Data System (ADS)

    Hu, Ping; Yang, Hai-bo; Pan, De-an; Wang, Hua; Tian, Jian-jun; Zhang, Shen-gen; Wang, Xin-feng; Volinsky, Alex A.

    2010-01-01

    Mn-Zn ferrite powders (Mn 0.5Zn 0.5Fe 2O 4) were prepared by the nitrate-citrate auto-combustion method and subsequently annealed in air or argon. The effects of heat treatment temperature on crystalline phases formation, microstructure and magnetic properties of Mn-Zn ferrite were investigated by X-ray diffraction, thermogravimetric and differential thermal analysis, scanning electron microscopy and vibrating sample magnetometer. Ferrites decomposed to Fe 2O 3 and Mn 2O 3 after annealing above 550 °C in air, and had poor magnetic properties. However, Fe 2O 3 and Mn 2O 3 were dissolved after ferrites annealing above 1100 °C. Moreover, the 1200 °C annealed sample showed pure ferrite phase, larger saturation magnetization ( Ms=48.15 emu g -1) and lower coercivity ( Hc=51 Oe) compared with the auto-combusted ferrite powder ( Ms=44.32 emu g -1, Hc=70 Oe). The 600 °C air annealed sample had the largest saturation magnetization ( Ms=56.37 emu g -1) and the lowest coercivity ( Hc=32 Oe) due to the presence of pure ferrite spinel phase, its microstructure and crystalline size.

  20. Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep

    SciTech Connect

    Li, Shengzhi; Eliniyaz, Zumrat; Zhang, Lanting; Sun, Feng; Shen, Yinzhong; Shan, Aidang

    2012-11-15

    This research focused on the formation and microstructural evolution of delta ferrite phase in SAVE12 steel. The formation of delta ferrite was due to the high content of ferrite forming alloy elements such as Cr, W, and Ta. This was interpreted through either JMatPro-4.1 computer program or Cr{sub eq} calculations. Delta ferrite was found in bamboo-like shape and contained large amount of MX phase. It was surrounded by Laves phases before creep or aging treatment. Annealing treatments were performed under temperatures from 1050 Degree-Sign C to 1100 Degree-Sign C and various time periods to study its dissolution kinetics. The result showed that most of the delta ferrite can be dissolved by annealing in single phase austenitic region. Dissolution process of delta ferrite may largely depend on dissolution kinetic factors, rather than on thermodynamic factors. Precipitation behavior during short-term (1100 h) creep was investigated at temperature of 600 Degree-Sign C under a stress of 180 MPa. The results demonstrated that delta ferrite became preferential nucleation sites for Laves phase at the early stage of creep. Laves phase on the boundary around delta ferrite showed relatively slower growth and coarsening rate than that inside delta ferrite. - Highlights: Black-Right-Pointing-Pointer Delta ferrite is systematically studied under heat treatment and short-term creep. Black-Right-Pointing-Pointer Delta ferrite contains large number of MX phase and is surrounded by Laves phases before creep or aging treatment. Black-Right-Pointing-Pointer Formation of delta ferrite is interpreted by theoretical and empirical methods. Black-Right-Pointing-Pointer Most of the delta ferrite is dissolved by annealing in single phase austenitic region. Black-Right-Pointing-Pointer Delta ferrite becomes preferential nucleation sites for Laves phase at the early stage of creep.

  1. Current topics in the field of materials technology of soft ferrites

    SciTech Connect

    Nomura, Takeshi; Ochiai, Tatusshiro

    1995-09-01

    The present paper focuses on the recent progress of materials technology for high performance soft ferrites. The electromagnetic properties of ferrites depend on the producing process and micro- and nano-structures. MnZn ferrite is a principal ferrite for high permeability and power uses. Recently, spray roasting method of Mn-Zn-Fe ternary system has been developed. High initial permeability over 20000 at 10kHz was achieved by using highly pure spray roasted powder of Mn-Fe binary system. Low power loss is of prime importance for power application. Control of grain boundary chemistry and grain size by the adequate selection of additives and firing conditions is required for achieving low power loss at high frequencies. NiCuZn ferrites for multilayer-ferrite chip-components fired under controlled oxygen partial pressure showed high Q-value. This could be explained by nanostructure of grain boundary. MnMgZn ferrites for deflection yoke cores satisfy high cost-performance. Problems of MnMgZn ferrites are loss characteristics and instability of initial permeability. Relaxation of permeability could be depressed by the control of chemical composition and microstructure. Fine magnetite powders by thermal decomposition of iron chloride are under development. This method may be a promising way to low cost and high performance toner for copy machines. High performance such as low loss or high permeability can be achieved by controlling ferrite microstructure and grain boundary chemistry. These can be attained by a highly pure raw powder, a small amount of additives, and an adequate firing program.

  2. Investigations into sub-ns pulse generation using ferrite-loaded coaxial lines

    NASA Astrophysics Data System (ADS)

    Bolton, H. R.; Dolan, J. E.; Shapland, A. J.; Parkes, D. M.; Trafford, K.; Kerr, B.

    1995-03-01

    Systems such as Pockels Cell drivers and UWB radar require electrical pulses of less than 200 ps rise-time and amplitude of 10 kV or greater into 50 ohms. Desired p.r.f.'s may be 50 kHz or higher in burst mode. The output rise-time of high power and p.r.f. capable pulsers is generally of the order 2-20 ns, and ferrite-loaded coaxial lines are one means of reducing the leading edge 10-90% rise-time to the order of 100-200 ps. The development of the fast-rising leading edge in ferrite lines is due to the non-linearity of the magnetic medium, and the consequent formation of an 'electromagnetic shock front' at the pulse leading edge. Over the past decade, the use of magnets to bias the ferrite has been found to improve output rise-time and amplitude characteristics considerably. Steady-state analyses made by Soviet analysts in the 1960's do not explain the magnet-biased ferrite line characteristics, and a numerical approach will be presented which shows how the microwave characteristics of the ferrite may be combined with the TEM transmission line equations to model electromagnetic shock wave propagation in such ferrite-loaded lines. It now appears reasonably clear that ferrite lines may be effectively modelled and designed in terms of parameters including the ferrite saturation magnetisation, and the dimensions of the line and the ferrite beads. Second order effects such as conductor and dielectric losses may also be taken into account if required.

  3. AF9 promotes hESC neural differentiation through recruiting TET2 to neurodevelopmental gene loci for methylcytosine hydroxylation

    PubMed Central

    Qiao, Yunbo; Wang, Xiongjun; Wang, Ran; Li, Yuanyuan; Yu, Fang; Yang, Xianfa; Song, Lu; Xu, Guoliang; Chin, Y Eugene; Jing, Naihe

    2015-01-01

    AF9 mutations have been implicated in human neurodevelopmental diseases and murine Af9 mediates histone methylation during cortical neuron generation. However, AF9 function and related mechanisms in human neurodevelopment remain unknown. Here we show that AF9 is necessary and sufficient for human embryonic stem cell (hESC) neural differentiation and neurodevelopmental gene activation. The 5-methylcytosine (5mC) dioxygenase TET2, which was identified in an AF9-associated protein complex, physically interacted with AF9. Both AF9 and TET2 co-localized in 5-hydroxymethylcytosine (5hmC)-positive hESC-derived neurons and were required for appropriate hESC neural differentiation. Upon binding to AAC-containing motifs, AF9 recruited TET2 to occupy the common neurodevelopmental gene loci to direct 5mC-to-5hmC conversion, which was followed by sequential activation of neural target genes and hESC neural commitment. These findings define an AF9–TET2 regulatory complex for modulating human neural development and reveal a novel mechanism by which the AF9 recognition specificity and TET2 hydroxylation activity cooperate to control neurodevelopmental gene activation. PMID:27462416

  4. Fabrication of silver-coated cobalt ferrite nanocomposite and the study of its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Kooti, M.; Saiahi, S.; Motamedi, H.

    2013-05-01

    A new silver coated cobalt ferrite nanocomposite, Ag@CoFe2O4, was prepared by a two-step procedure. In the first step, cobalt ferrite nanoparticles were synthesized by a combustion method using glycine as a fuel. This ferrite was then coated with nanosilver via chemical reduction of Ag+ solution. The as-synthesized Ag@CoFe2O4 was characterized by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The antibacterial activity of this composite was investigated against some Gram-positive and Gram-negative bacteria and compared with those of silver nanoparticles and some standard antibacterial drugs.

  5. Broadband impedance-matched electromagnetic structured ferrite composite in the megahertz range

    SciTech Connect

    Parke, L.; Hibbins, A. P.; Sambles, J. R.; Youngs, I. J.

    2014-06-02

    A high refractive-index structured ferrite composite is designed to experimentally demonstrate broadband impedance matching to free-space. It consists of an array of ferrite cubes that are anisotropically spaced, thereby allowing for independent control of the effective complex permeability and permittivity. Despite having a refractive index of 9.5, the array gives less than 1% reflection and over 90% transmission of normally incident radiation up to 70 MHz for one of the orthogonal linear polarisations lying in a symmetry plane of the array. This result presents a route to the design of MHz-frequency ferrite composites with bespoke electromagnetic parameters for antenna miniaturisation.

  6. Characterization and Applications of Micro- and Nano- Ferrites at Microwave and Millimeter Waves

    NASA Astrophysics Data System (ADS)

    Chao, Liu

    Ferrite materials are one of the most widely used magnetic materials in microwave and millimeter wave applications such as radar, wireless communication. They provide unique properties for microwave and millimeter wave devices especially non-reciprocal devices. Some ferrite materials with strong magnetocrystalline anisotropy fields can extend these applications to tens of GHz range while reducing the size, weight and cost. This thesis focuses on characterization of such ferrite materials as micro- and nano-powder and the fabrication of the devices. The ferrite materials with strong magnetocrystalline anisotropy field are metal/non-metal substituted iron oxides oriented in low crystal symmetry. The ferrite materials characterized in this thesis include M-type hexagonal ferrites such as barium ferrite (BaFe12O19), strontium ferrite (SrFe12O19), epsilon phase iron oxide (epsilon-Fe 2O3), substituted epsilon phase iron oxide (epsilon-Ga xFe2-xO3, epsilon-AlxFe2-xO 3). These ferrites exhibit great anisotropic magnetic fields. A transmission-reflection based in-waveguide technique that employs a vector network analyzer was used to determine the scattering parameters for each sample in the microwave bands (8.2--40 GHz). From the S-parameters, complex dielectric permittivity and complex magnetic permeability are evaluated by an improved algorithm. The millimeter wave measurement is based on a free space quasi-optical spectrometer. Initially precise transmittance spectra over a broad millimeter wave frequency range from 40 GHz to 120 GHz are acquired. Later the transmittance spectra are converted into complex permittivity and permeability spectra. These ferrite powder materials are further characterized by x-ray diffraction (XRD) to understand the crystalline structure relating to the strength and the shift of the ferromagnetic resonance affected by the particle size. A Y-junction circulator working in the 60 GHz frequency band is designed based on characterized M

  7. Stability of Y–Ti–O precipitates in friction stir welded nanostructured ferritic alloys

    DOE PAGESBeta

    Yu, Xinghua; Mazumder, B.; Miller, M. K.; David, S. A.; Feng, Z.

    2015-01-19

    Nanostructured ferritic alloys, which have complex microstructures which consist of ultrafine ferritic grains with a dispersion of stable oxide particles and nanoclusters, are promising materials for fuel cladding and structural applications in the next generation nuclear reactor. This paper evaluates microstructure of friction stir welded nanostructured ferritic alloys using electron microscopy and atom probe tomography techniques. Atom probe tomography results revealed that nanoclusters are coarsened and inhomogeneously distributed in the stir zone and thermomechanically affected zone. Three hypotheses on coarsening of nanoclusters are presented. Finally, the hardness difference in different regions of friction stir weld has been explained.

  8. Low temperature bainitic ferrite: Evidence of carbon super-saturation and tetragonality

    DOE PAGESBeta

    Garcia-Mateo, C.; Jimenez, J. A.; Yen, Hung-Wei; Miller, Michael K.; Morales-Rivas, L; Kuntz, M; Ringer, S. P.; Yang, Jer-Ren; Caballero, Francesca G.

    2015-03-31

    Experimental evidence indicates that bainitic ferrite formed by transformation at low temperatures (200-350 °C) includes quantities of carbon in solid solution far beyond those expected from para-equilibrium. A change in the conventional symmetry of the bainitic ferrite lattice from cubic to tetragonal explains the abnormal solid solubility detected. This carbon supersaturation was measured by atom probe tomography, and the tetragonality of the bainitic ferrite, was characterized by means of X-ray diffraction analysis and high resolution transmission electron microscopy.

  9. Statin Therapy for the Prevention of Atrial Fibrillation Trial (SToP AF trial)

    PubMed Central

    Negi, Smita; Shukrullah, Irfan; Veledar, Emir; Bloom, Heather L.; Jones, Dean P.; Dudley, Samuel C.

    2010-01-01

    Background Inflammation and oxidative stress are associated with atrial fibrillation (AF). Statins have antioxidant and anti-inflammatory properties. We tested if atorvastatin reduced AF recurrence after DC cardioversion (CV) by modifying systemic oxidative stress and inflammation. (NCT00252967) Methods and Results In a randomized, double-blinded, placebo-controlled trial, patients with atrial fibrillation/flutter (AF) were randomized to receive either atorvastatin 80 mg (n=33) or placebo (n=31) before CV. Treatment was continued for 12 months or until AF recurred. Serum oxidative stress markers (ratios of oxidized to reduced glutathione and cysteine, derivatives of reactive oxygen species, isoprostanes) and inflammatory markers [ high sensitivity C- reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-1β(IL-1β), tumor necrosis factor-α (TNFα)] were measured at baseline and on follow-up. AF recurred in 22 (66.7%) of atorvastatin and 26 (83.9%) of placebo group (p=0.2). The adjusted hazard ratio of having recurrence on atorvastatin versus on placebo was 0.99 (95% CI: 0.98-1.01, p=0.3). There was no significant difference in the time to recurrence using Kaplan-Meier survival estimates (median (IR): 29 (2-145) days vs. 22 (7-70) days, p=0.9). While no significant effect was seen on oxidative stress, 2 of 4 inflammatory markers, IL-6 (adjusted OR: 0.59, 95% CI: 0.35-0.97, p= 0.04) and hs-CRP (adjusted OR: 0.59, 95% CI: 0.37-0.95, p=0.03) were significantly lowered with atorvastatin. Cholesterol levels significantly decreased with atorvastatin (p=0.03). Conclusions High dose atorvastatin did not reduce the recurrence of AF after CV. It reduced selective markers of inflammation without affecting systemic oxidative stress. Failure of atorvastatin to prevent AF recurrence may be due to its failure to affect oxidative stress. PMID:20946227

  10. Natalizumab-induced POU2AF1/Spi-B upregulation

    PubMed Central

    Meira, Maria; Sievers, Claudia; Hoffmann, Francine; Haghikia, Aiden; Rasenack, Maria; Décard, Bernhard F.; Kuhle, Jens; Derfuss, Tobias; Kappos, Ludwig

    2016-01-01

    Objectives: To assess messenger RNA (mRNA) expression of POU2AF1 and Spi-B and their potential regulatory microRNAs (miRNAs) in natalizumab-treated patients with multiple sclerosis and in therapy-associated progressive multifocal leukoencephalopathy (PML). Methods: Expression of POU2AF1/Spi-B was analyzed by using real-time reverse transcription PCR assays on isolated B/CD8+ T lymphocytes and peripheral blood mononuclear cells (PBMCs) from cohorts of untreated and natalizumab-treated patients with and without PML. Longitudinal expression analysis was performed on CD4+, CD8+ T and B cells from 14 patients who interrupted natalizumab therapy for 8 weeks. The miRNA profiling was conducted in PBMCs from 5 untreated and 5 natalizumab-treated patients using low-density arrays followed by validation with single miRNAs assays in untreated and natalizumab-treated patients. Results: POU2AF1 and Spi-B mRNAs were upregulated in B and CD8+ T cells from natalizumab-treated patients, which was validated in PBMCs from different cohorts of natalizumab-treated patients with and without PML, with a noteworthy higher expression of Spi-B in patients with PML. In contrast, downregulation of POU2AF1/Spi-B expression was measured in B and CD8+ T cells after natalizumab discontinuation. Seventeen differentially expressed miRNAs including miR-10b, a regulator of POU2AF1 mRNA, were identified in long-term natalizumab-treated patients compared with untreated ones. Conclusions: Upregulation of POU2AF1 and Spi-B, known transactivators of the JC virus, the causative agent for PML, and its association with occurrence of PML in natalizumab-treated patients, corroborates POU2AF1/Spi-B as potential biomarkers for PML risk, which merits further evaluation. PMID:27088119

  11. Evaluation Of Shielding Efficacy Of A Ferrite Containing Ceramic Material

    SciTech Connect

    Verst, C.

    2015-10-12

    The shielding evaluation of the ferrite based Mitsuishi ceramic material has produced for several radiation sources and possible shielding sizes comparative dose attenuation measurements and simulated projections. High resolution gamma spectroscopy provided uncollided and scattered photon spectra at three energies, confirming theoretical estimates of the ceramic’s mass attenuation coefficient, μ/ρ. High level irradiation experiments were performed using Co-60, Cs-137, and Cf-252 sources to measure penetrating dose rates through steel, lead, concrete, and the provided ceramic slabs. The results were used to validate the radiation transport code MCNP6 which was then used to generate dose rate attenuation curves as a function of shielding material, thickness, and mass for photons and neutrons ranging in energy from 200 keV to 2 MeV.

  12. Magnetic Cobalt Ferrite Nanocrystals For an Energy Storage Concentration Cell.

    PubMed

    Dai, Qilin; Patel, Ketan; Donatelli, Greg; Ren, Shenqiang

    2016-08-22

    Energy-storage concentration cells are based on the concentration gradient of redox-active reactants; the increased entropy is transformed into electric energy as the concentration gradient reaches equilibrium between two half cells. A recyclable and flow-controlled magnetic electrolyte concentration cell is now presented. The hybrid inorganic-organic nanocrystal-based electrolyte, consisting of molecular redox-active ligands adsorbed on the surface of magnetic nanocrystals, leads to a magnetic-field-driven concentration gradient of redox molecules. The energy storage performance of concentration cells is dictated by magnetic characteristics of cobalt ferrite nanocrystal carriers. The enhanced conductivity and kinetics of redox-active electrolytes could further induce a sharp concentration gradient to improve the energy density and voltage switching of magnetic electrolyte concentration cells. PMID:27440206

  13. Soft ferrite materials for magnetic temperature transducers and applications

    NASA Astrophysics Data System (ADS)

    Miclea, C.; Tanasoiu, C.; Miclea, C. F.; Gheorghiu, A.; Tanasoiu, V.

    2005-04-01

    Soft ferrites in the CuZnTi system, having the formula Cu 1-xZn xTi yFe 2-yO 4, with 0.50⩽ x⩽0.60 and 0.00⩽ y⩽0.05 were investigated as a function of composition, sintering temperature and cooling speed, in order to obtain materials with controlled TC and very high change rate of permeability with temperature around their TC. The effect of Zn and Ti additions was a drastic change of the Curie temperature with about 10-12 °C for each atomic percent of Zn and Ti introduced into the spinel lattice while the cooling speed changed the behaviour of magnetic permeability with temperature around the Curie point. An application using such magnetic temperature sensors for a thermostat is presented.

  14. Electrophoretic deposition of nickel zinc ferrite nanoparticles into microstructured patterns

    NASA Astrophysics Data System (ADS)

    Kelly, Stefan J.; Wen, Xiao; Arnold, David P.; Andrew, Jennifer S.

    2016-05-01

    Using DC electric fields, nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) nanoparticles (Dh =16.6 ± 3.6 nm) are electrophoretically deposited onto silicon substrates to form dense structures defined by photoresist molds. Parameters such as electric field, bath composition, and deposition time are tuned to produce films ranging in thickness from 177 to 805 nm. The deposited films exhibit soft magnetic properties with a saturation magnetization of 60 emu/g and a coercivity of 2.6 kA/m (33 Oe). Additionally, the influence of the photoresist mold on the deposit profile is studied, and patterned films with different shapes (lines, squares, circles, etc.) are demonstrated with feature sizes down to 5 μm.

  15. Growth, structure, morphology, and magnetic properties of Ni ferrite films

    PubMed Central

    2013-01-01

    The morphology, structure, and magnetic properties of nickel ferrite (NiFe2O4) films fabricated by radio frequency magnetron sputtering on Si(111) substrate have been investigated as functions of film thickness. Prepared films that have not undergone post-annealing show the better spinel crystal structure with increasing growth time. Meanwhile, the size of grain also increases, which induces the change of magnetic properties: saturation magnetization increased and coercivity increased at first and then decreased. Note that the sample of 10-nm thickness is the superparamagnetic property. Transmission electron microscopy displays that the film grew with a disorder structure at initial growth, then forms spinel crystal structure as its thickness increases, which is relative to lattice matching between substrate Si and NiFe2O4. PMID:23622034

  16. Ferroelectric and ferromagnetic properties of Gd substituted nickel ferrite

    NASA Astrophysics Data System (ADS)

    Kamala Bharathi, K.; Markandeyulu, G.

    2008-04-01

    Ferromagnetic and ferroelectric characteristics of Gd substituted nickel ferrite (NiOṡFe1.925Gd0.075O3) were investigated. The material formed in the cubic inverse spinel phase and in addition, a small amount of GdFeO3 phase was identified. A small distortion of the cubic lattice was observed upon the substitution of Fe by Gd in the B site. Substitution of Gd for Fe lowered the saturation magnetization. However, the saturation magnetostriction is seen not to change significantly by the substitution of Gd. From the temperature variation of dielectric constant measurement, the ferroelectric transition temperature was found to be 512K. The existence of the ferroelectricity was confirmed from the ferroelectric loop. The (high) dielectric constant with frequency is seen to reveal a dispersion of relaxation times.

  17. Magnetoelectric Effects in hexagonal ferrite-PZT bilayers

    NASA Astrophysics Data System (ADS)

    Mathe, V. M.; Srinivasan, G.

    2008-03-01

    Magnetoelectric (ME) bilayers consisting of magnetostrictive and a piezoelectric layer are of interest for studies on the nature of ME interactions and useful technologies. Co2Z and Zn2Y are well known hexagonal ferrites with easy plane or uniaxial anisotropy. PZT has high piezoelectric coefficient. This study is on samples with Co2Z or Zn2Y as a magnetostrictive layer and PZT as a piezoelectric layer to form magnetoelectric bilayers. Low frequency (100 Hz) ME coefficient was measured over 0-17 kOe for various orientations of bilayers in a plane parallel to ac and bias magnetic fields. We measured a strong dependence of the ME voltage coefficients on magneitude and orientation of the bias field. The data are compared with theory. VLM gratefully acknowledge the award of a BOYSCAST fellowship and a FAST TRACK fellowship by DST, India. The research was supported by NSF grants.

  18. Investigation of structural and electrical properties of mixed ferrite system

    SciTech Connect

    Astik, Nidhi M. Jha, Prafulla K.

    2015-05-15

    In the present work, structural and electrical properties of mixed ferrite systems are studied. As prepared compound of Co{sub 0.85}Ca{sub 0.15-y}Cd{sub y}Fe{sub 2}O{sub 4} (y=0.10, 0.15) is synthesized in polycrystalline form, using the stoichiometric mixture of oxides with conventional standard ceramic route with double sintering at 950°C and 1100°C and characterized by X-ray diffraction. The X-ray diffraction pattern confirms the presence of cubic (FCC) structure. The sharp intensified peaks in X-ray diffraction pattern clearly indicate the completeness of reaction.

  19. Electrical and magnetic properties of Co-Zn-Mg ferrite

    NASA Astrophysics Data System (ADS)

    Oza, M. H.; Baldha, G. J.

    2016-05-01

    The series Co(0.8)Zn0.2-XMgXFe2O4 has been synthesized using standard ceramic technique and characterized using different techniques. The XRD analysis shows single phase cubic structure of the sample. It was also observed from XRD that lattice constant values calculated from these data were found to increase on increasing value of concentration X. The a.c susceptibility was carried out which exhibited ferromagnetic ordering. The Neel's temperature Tc determined from it increases with increasing X. There is an agreement in ferrimagnetic behaviour between magnetization and susceptibility data. This also suggests that A-B interaction increases with increasing X. The electrical properties of Zn - Mg substituted Co ferrite were found through DC resistivity measurements.

  20. Mechanical behaviour of ferritic ODS steels - Temperature dependancy and anisotropy

    NASA Astrophysics Data System (ADS)

    Fournier, B.; Steckmeyer, A.; Rouffie, A.-L.; Malaplate, J.; Garnier, J.; Ratti, M.; Wident, P.; Ziolek, L.; Tournie, I.; Rabeau, V.; Gentzbittel, J. M.; Kruml, T.; Kubena, I.

    2012-11-01

    Ferritic 14%Cr and 18%Cr ODS steels produced at CEA in round bars or plates were tested mechanically. The present paper reports results obtained in tension, impact, fatigue, creep and toughness tests. These tests were carried out at various temperatures and in different directions. These materials show a pronounced anisotropy at all tested temperatures. No matter the loading, the transversal direction is always found to be far less resistant than the longitudinal one. This anisotropy is mainly observed in terms of damage mechanisms, with intergranular fracture preferentially occurring along the extrusion direction. This intergranular fracture mode leads to very low and anisotropic toughness values and to the absence of tertiairy creep stage, pointing out the unstable nature of fracture, even at high temperature. The unrealistically high values of the Norton exponent measured in creep suggests the existence of a threshold stress, which is consistent with the mainly kinematic nature of the stress as revealed by fatigue tests.

  1. Calculation of the ferrite volume in some dual phase steels

    SciTech Connect

    Qixun, D.; Ruzeng, Y.

    1997-04-01

    The relation between the {gamma}/{gamma} + {alpha} boundary temperature, T{sub {alpha}}, and the equivalent values of [Cr] and [Ni], as well as the variation of the ferrite volume, V{sub f}, with the temperature in {alpha} + {gamma} dual-phase steels have been studied. With the aid of a computer, the regressive expressions derived from the experimental results are: T{sub {alpha}} (C) = T{sub 3} + 21.2 [Cr] {minus} 15.8 [Ni] + 223; V{sub f} (%) = 0.715 {l_brace}exp [0.015(T-T{sub {delta}})] {minus} exp[0.015(T{sub c}-T{sub {delta}})]{r_brace} + 1.85 exp [0.0083(T{sub {alpha}}-T{sub c})].

  2. Preparation of transparent conductors ferroelectric memory materials and ferrites

    DOEpatents

    Bhattacharya, Raghu Nath; Ginley, David S.

    1998-01-01

    A process for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

  3. Preparation of transparent conductors ferroelectric memory materials and ferrites

    DOEpatents

    Bhattacharya, R.N.; Ginley, D.S.

    1998-07-28

    A process is described for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

  4. Magnetic and ultrasonic studies on stable cobalt ferrite magnetic nanofluid.

    PubMed

    Nabeel Rashin, M; Hemalatha, J

    2014-03-01

    Stable cobalt ferrite nanofluids of various concentrations have been prepared through co-precipitation method. Structural and morphological studies of nanoparticles are made with the help of X-ray diffraction technique and Transmission Electron Microscope respectively and it is found that the particles exhibit face centered cubic structure with an average size of 14 nm. The magnetic properties of the nanofluids have been analyzed at room temperature which revealed ferromagnetic behavior and also the very low value of coupling constant which ensures the negligible interparticle interaction in the absence of magnetic field. Ultrasonic investigations have been made for the nanofluids at different temperatures and magnetic fields. The temperature effects are explained with the help of open and close-packed water structure. The inter particle interactions of surface modified CoFe2O4 particles and the cluster formation at higher concentrations are realized through the variations in ultrasonic parameters. PMID:24188514

  5. Soliton interactions between multivalued localized waveguide channels within ferrites.

    PubMed

    Nguepjouo, Francis T; Kuetche, Victor K; Kofane, Timoleon C

    2014-06-01

    In this paper, we investigate both analytically and numerically the localized multivalued waveguide channels-the loop solitons-dynamics within a ferrite slab. In the starting point of the work, we solve in detail the initial value problem of the system while unveiling the existence of multivalued waveguide channels solutions. Paying particular interest to the nonlinear scattering among these excitations, we study extensively the different kinds of interacting features between these localized waves alongside the depiction of their energy densities. As a result, we find that the interactions can be attractive or repulsive depending strongly on the ratio of the amplitudes of the interacting structures. In the wake of these results, we address some physical implications, accordingly. PMID:25019903

  6. Microwave-assisted synthesis and characterization of nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Carpenter, Gopal; Sen, Ravindra; Malviya, Nitin; Gupta, Nitish

    2015-08-01

    Nickel ferrite nanoparticles (NiFe2O4) were successfully prepared by microwave-assisted combustion method (MWAC) using citric Electron acid as a chelating agent. NiFe2O4 nanoparticles were characterized by X-ray diffraction (XRD) pattern, Scanning Microscopy (SEM), Fourier transform infrared (FTIR) and UV-Visible techniques. XRD analysis revealed that NiFe2O4 nanoparticles have spinel cubic structure with the average crystalline size of 26.38 nm. SEM analysis revealed random and porous structural morphology of particles and FTIR showed absorption bands related to octahedral and tetrahedral sites, in the range 400-600cm-1 which strongly favor the formation of NiFe2O4 nanoparticles. The optical band gap is determined by UV Visible method and found to be 5.4 eV.

  7. Dielectric properties of Ni substituted Li-Zn ferrites

    NASA Astrophysics Data System (ADS)

    Soibam, Ibetombi; Phanjoubam, Sumitra; Radhapiyari, L.

    2010-05-01

    Li 0.4-0.5xZn 0.2Ni x Fe 2.4-0.5xO 4 ferrites with x varying from 0.02 to 0.1 in steps of 0.02 have been synthesized by the citrate precursor method and investigated for their dielectric properties. A decrease in the value of room temperature dielectric constant is observed with the increase in Ni concentration. It has been explained in terms of space charge polarization and Koop's two layer model. The variation in dielectric constant with frequency shows dispersion while a resonance peak could be seen in the variation of dielectric loss with frequency. With increase in temperature the dielectric constant and dielectric loss increased, which have been discussed in terms of polarization and the Debye-type of dispersion. Possible mechanism contributing to the above process is discussed.

  8. Microwave-assisted synthesis and characterization of nickel ferrite nanoparticles

    SciTech Connect

    Carpenter, Gopal; Sen, Ravindra; Gupta, Nitish; Malviya, Nitin

    2015-08-28

    Nickel ferrite nanoparticles (NiFe{sub 2}O{sub 4}) were successfully prepared by microwave-assisted combustion method (MWAC) using citric Electron acid as a chelating agent. NiFe{sub 2}O{sub 4} nanoparticles were characterized by X-ray diffraction (XRD) pattern, Scanning Microscopy (SEM), Fourier transform infrared (FTIR) and UV-Visible techniques. XRD analysis revealed that NiFe{sub 2}O{sub 4} nanoparticles have spinel cubic structure with the average crystalline size of 26.38 nm. SEM analysis revealed random and porous structural morphology of particles and FTIR showed absorption bands related to octahedral and tetrahedral sites, in the range 400–600cm{sup −1} which strongly favor the formation of NiFe{sub 2}O{sub 4} nanoparticles. The optical band gap is determined by UV Visible method and found to be 5.4 eV.

  9. Mössbauer study of chromium-substituted nickel ferrites

    NASA Astrophysics Data System (ADS)

    Gismelseed, Abbasher M.; Yousif, Ali A.

    2005-12-01

    The structural and magnetic properties of the Cr substituted NiCr xFe 1-xO 4 ( 0⩽x⩽1.4) spinel ferrites have been investigated by means of X-ray diffraction and Mössbauer spectroscopy techniques. Their crystal structures are found to be pure cubic phases. The Mössbauer spectra at 295 and 78 K of all samples showed two well-resolved magnetic patterns corresponding to the tetrahedral A-sites and octahedral B-sites. The cation distributions driven from the area under resonance curve of each site revealed that the compounds are gradually transferred from perfect inverse spinel to partially normal spinel structure. The behavior of the magnetic properties as a function of Cr 3+ concentration has been explained on the basis of the driven cation distribution and it showed that the chrome-rich compositions can be explained in terms of the non-collinear spin model.

  10. Cr3+ substituted spinel ferrite nanoparticles with high coercivity

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Zuo, Xudong; Zhang, Dongmei; Wu, Chengwei; Silva, S. Ravi P.

    2016-06-01

    The low coercivity of spinel ferrites is a major barrier that significantly limits their use in high density magnetic recording applications. By controlling the substituting content of Cr3+, in this article we describe how magnetic CoCr x Fe2‑x O4 (0 < x < 1.2) nanoparticles with coercivity of up to 6.4 kOe were successfully obtained by the hydrothermal process. The high coercivity is attributed to the synergetic effects of magnetocrystalline anisotropy and the nanoscale size effect. X-ray diffraction analysis confirmed the spinel structure of the nanoparticles with transmission electron microscopy (TEM) suggesting regular tetragonal morphology. The TEM indicated an edge length ranging from 15 nm to 150 nm, which increases monotonically with increasing Cr content. Raman analyses supported the proposed model on the formation mechanism of the nanoparticles, i.e. heterogeneous and homogeneous nucleation.

  11. Cr(3+) substituted spinel ferrite nanoparticles with high coercivity.

    PubMed

    Zhang, Wei; Zuo, Xudong; Zhang, Dongmei; Wu, Chengwei; Silva, S Ravi P

    2016-06-17

    The low coercivity of spinel ferrites is a major barrier that significantly limits their use in high density magnetic recording applications. By controlling the substituting content of Cr(3+), in this article we describe how magnetic CoCr x Fe2-x O4 (0 < x < 1.2) nanoparticles with coercivity of up to 6.4 kOe were successfully obtained by the hydrothermal process. The high coercivity is attributed to the synergetic effects of magnetocrystalline anisotropy and the nanoscale size effect. X-ray diffraction analysis confirmed the spinel structure of the nanoparticles with transmission electron microscopy (TEM) suggesting regular tetragonal morphology. The TEM indicated an edge length ranging from 15 nm to 150 nm, which increases monotonically with increasing Cr content. Raman analyses supported the proposed model on the formation mechanism of the nanoparticles, i.e. heterogeneous and homogeneous nucleation. PMID:27159283

  12. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent

    SciTech Connect

    Berggren, M.H.; Jha, M.C.

    1989-10-01

    AMAX Research Development Center (AMAX R D) investigated methods for enhancing the reactivity and durability of zinc ferrite desulfurization sorbents. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For this program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such as size, strength, and specific surface area during 10 cycles of sulfidation and oxidation. Two base case sorbents, a spherical pellet and a cylindrical extrude used in related METC-sponsored projects, were used to provide a basis for the aimed enhancement in durability and reactivity. Sorbent performance was judged on the basis of physical properties, single particle kinetic studies based on thermogravimetric (TGA) techniques, and multicycle bench-scale testing of sorbents. A sorbent grading system was utilized to quantify the characteristics of the new sorbents prepared during the program. Significant enhancements in both reactivity and durability were achieved for the spherical pellet shape over the base case formulation. Overall improvements to reactivity and durability were also made to the cylindrical extrude shape. The primary variables which were investigated during the program included iron oxide type, zinc oxide:iron oxide ratio, inorganic binder concentration, organic binder concentration, and induration conditions. The effects of some variables were small or inconclusive. Based on TGA studies and bench-scale tests, induration conditions were found to be very significant.

  13. Electrical and optical properties of nickel ferrite/polyaniline nanocomposite.

    PubMed

    Khairy, M; Gouda, M E

    2015-07-01

    Polyaniline-NiFe2O4 nanocomposites (PANI-NiFe2O4) with different contents of NiFe2O4 (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol-gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI-NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg  = 1.0 for PANI-NiFe2O4 nanocomposite. PMID:26199745

  14. Electrical and optical properties of nickel ferrite/polyaniline nanocomposite

    PubMed Central

    Khairy, M.; Gouda, M.E.

    2014-01-01

    Polyaniline–NiFe2O4 nanocomposites (PANI–NiFe2O4) with different contents of NiFe2O4 (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol–gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI–NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg = 1.0 for PANI–NiFe2O4 nanocomposite. PMID:26199745

  15. Carbides in a High-Chromium Ferritic/Martensitic Steel

    NASA Astrophysics Data System (ADS)

    Shen, Yin Zhong; Ji, Bo; Zhou, Xiao Ling; Zhu, Jun

    2014-06-01

    The precipitate phases in an 11 pct Cr ferritic/martensitic steel normalized at 1323 K (1050 °C) for 0.5 hour and tempered at 1053 K (780 °C) for 1.5 hours have been investigated. Except for dominant phases, Cr-rich M23C6 carbide and Nb-rich, Ta-Nb-rich, and V-rich MC carbides, needle-like precipitates with a typical size of 70 to 310 and 10 to 30 nm for the length of the long and short axis of the needles, respectively, were also observed on the extraction carbon replica of the steel. The typical metallic element composition of the needle-like precipitates is about 53-82Fe, 14-26Cr, 0.5-18Ta, 1-6W, and 2-5Co in atomic pct. Through energy dispersive X-ray analysis and electron diffraction along with calculations regarding lattice parameter and interplanar spacing, the needle-like precipitates were identified as a Fe-rich M5C2 carbide, which is not known to have been reported previously in high-chromium steels. The M5C2 carbide has a base-centered monoclinic crystal structure with the approximate lattice parameters a/ b/ c = 1.142/0.5186/0.5383 nm and β = 104.68 deg. The formation of the Fe-rich M5C2 carbides in the steel has been discussed. The effect of chromium content in matrix and boron addition on the precipitate phases in ferritic/martensitic steels has also been discussed.

  16. A Micro-Alloyed Ferritic Steel Strengthened by Nanoscale Precipitates

    SciTech Connect

    Shen, Yongfeng; Wang, Chong M.; Sun, Xin

    2011-08-04

    A high strength ferritic steel with finely dispersive precipitates was investigated to reveal the fundamental strengthening mechanisms. Using energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM), fine carbides with an average diameter of 10 nm were observed in the ferrite matrix of the 0.08%Ti steel, and some cubic M23C6 precipitates were also observed at the grain boundaries and the interior of grains. The dual precipitate structure of finely dispersive TiC precipitates in the matrix and coarse M23C6 at grain boundaries provides combined matrix and grain boundary strengthening. The calculated amount of precipitation strengthening by the carbides was approximately 450 ~ 630 MPa, depending on the average size of nanoscale precipitates. This value is two or three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels. Dislocation densities increased from 3.42×1013 m-2 to 1.69 × 1014 m-2, espectively, with increasing tensile strain from 5.5% to 22%. The effect of the particle size, particle distribution and intrinsic particle strength have been investigated through dislocation dynamics (DD) simulations and the relationship for resolved shear stress for single crystal under this condition has been presented using simulation data. The results show that the finely dispersive precipitates can strengthen the material by pinning the dislocations up to a certain shear stress and retarding the recovery as well as annihilation of dislocations. The DD results also show that strengthening is not only a function of the density of the nano-scale precipitates but also of their size.

  17. Design, fabrication, testing and delivery of a feasibility model laminated ferrite memory

    NASA Technical Reports Server (NTRS)

    Heckler, H. C.

    1973-01-01

    The effect of using multiword addressing with laminated ferrite arrays was made. Both a reduction in the number of components, and a reduction in power consumption was obtained for memory capacities between one million bits and one million words. An investigation into the effect of variations in the processing steps resulted in a number of process modifications that improved the quality of the arrays. A feasibility model laminated ferrite memory system was constructed by modifying a commercial plated wire memory system to operate with laminated ferrite arrays. To provide flexibility for the testing of the laminated ferrite memory, an exerciser has been constructed to automatically control the loading and recirculation of arbitrary size checkerboard patterns of one's and zero's and to display the patterns of stored information on a CRT screen.

  18. Detection and quantification of solute clusters in a nanostructured ferritic alloy

    NASA Astrophysics Data System (ADS)

    Miller, M. K.; Reinhard, D.; Larson, D. J.

    2015-07-01

    A series of simulated atom probe datasets were examined with a friends-of-friends method to establish the detection efficiency required to resolve solute clusters in the ferrite phase of a 14YWT nanostructured ferritic alloy. The size and number densities of solute clusters in the ferrite of the as-milled mechanically-alloyed condition and the stir zone of a friction stir weld were estimated with a prototype high-detection-efficiency (∼80%) local electrode atom probe. High number densities, 1.8 × 1024 m-3 and 1.2 × 1024 m-3, respectively of solute clusters containing between 2 and 9 solute atoms of Ti, Y and O and were detected for these two conditions. These results support first principle calculations that predicted that vacancies stabilize these Ti-Y-O- clusters, which retard diffusion and contribute to the excellent high temperature stability of the microstructure and radiation tolerance of nanostructured ferritic alloys.

  19. Impedance spectroscopy studies in cobalt ferrite-reduced graphene oxide nanocomposite

    NASA Astrophysics Data System (ADS)

    Supriya, Sweety; Kumar, Sunil; Kar, Manoranjan

    2016-05-01

    (1-x)Cobalt ferrite-(x)reduced graphene oxidenanocomposites with x=0, 0.1, 0.2 and 0.3 were prepared by the ultrasonic method. The crystal symmetry modification due to reduced graphene oxide and cobalt ferrite interaction has been studied by employing the X-ray diffraction technique. Morphology of the samples was studied by the Field emission scanning electron microscopy (FE-SEM). Study on electrical properties of the cobalt ferrite-reduced graphene oxide nanocomposites explores the possible application of these composites as anode material. Impedance decreases with an increase in frequency as well as temperature, which supports an increase in ac electrical conductivity. The modified Debye relaxation model can explain the behavior of impedance in cobalt ferrite-reduced graphene oxide nanocomposites.

  20. Low temperature synthesis of nanocrystalline lithium ferrite by a modified citrate gel precursor method

    SciTech Connect

    Verma, Seema; Joy, P.A.

    2008-12-01

    Single phase nanocrystalline lithium ferrite is synthesized by a modified citrate gel precursor technique. Ferrite nanoparticles of average size of 8 nm, obtained after calcination of the citrate gel made by the usual method at 450 deg. C, show superparamagnetic behavior. However, small amounts of {alpha}-Fe{sub 2}O{sub 3} is formed as an impurity phase due to the initial formation of some {gamma}-Fe{sub 2}O{sub 3} phase. On the other hand, when the pH of the mixed solution is increased to 7 after the addition of ammonia solution, a lower calcination temperature of 200 deg. C is sufficient for the formation of single phase lithium ferrite nanoparticles of size 30 nm. No impurity phases are detected when the nanocrystalline powders are calcined at higher temperatures. The magnetic properties of the ferrite nanoparticles of different sizes obtained by calcining the powders at different temperatures are studied.

  1. Material for magnetostrictive sensors and other applications based on ferrite materials

    DOEpatents

    McCallum, R. William; Snyder, John E.; Dennis, Kevin W.; Schwichtenberg, Carl R.; Jiles, David C.

    2002-03-05

    The present invention provides magnetostrictive composites that include an oxide ferrite and metallic binders which provides mechanical properties that make the magnetostrictive compositions effective for use as sensors and actuators.

  2. Friction and wear of single-crystal manganese-zinc ferrite

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1979-01-01

    Sliding friction experiments were conducted with single crystal manganese-zinc ferrite in contact with itself and with transition metals. Results indicate mating highest atomic density directions (110) on matched crystallographic planes exhibit the lowest coefficient of friction, indicating that direction is important in the friction behavior of ferrite. Matched parallel high atomic density planes and crystallographic directions at the interface exhibit low coefficients of friction. The coefficients of friction for ferrite in contact with various metals are related to the relative chemical activity of these metals. The more active the metal, the higher the coefficient of friction. Cracking and the formation of hexagon- and rectangular-shaped platelet wear debris due to cleavages of (110) planes are observed on the ferrite surfaces as a result of sliding.

  3. Two-magnon processes and ferrimagnetic linewidth calculation in manganese ferrite

    NASA Astrophysics Data System (ADS)

    Flores, A. G.; Raposo, V.; Torres, L.; Iñiguez, J.

    1999-04-01

    A procedure has been developed to obtain the two-magnon linewidth contributions in single and polycrystalline ferrites in which, working with ferrimagnetic resonance experiments, the applied field was only slightly larger than the value required to saturate the sample. This theory has been shown to work in manganese ferrites. Single-crystal MnFe2O4 has been prepared by the floating-zone technique and polycrystalline ferrite by the ceramic method. The spinel structure and composition have been confirmed by x-ray and inductively coupled plasma spectrometry, respectively. Fitting of the experimental ferrimagnetic resonance linewidth obtained by means of the Bloch-Bloembergern formalism show errors less than 4%. The fit gave the following parameters: averaged radius of the sample surface pits, porosity in polycrystalline sample, activation energy, and values of the conductivity. The values of the activation energy imply the existence of Fe2+ cations in the sample. Additional measurements on magnetization in manganese ferrites are presented.

  4. Improvements of magnetic properties of Sr ferrite magnets by substitutions of La and Co

    SciTech Connect

    Ogata, Yasunobu; Kubota, Yutaka; Takami, Takashi; Tokunaga, Masaaki; Shinohara, Tadashi

    1999-09-01

    Recently, it is intensively required to improve the magnetic properties of Sr ferrite magnets in order to decrease the weight of motors used in automobiles and to improve the efficiency of motors used in electric appliances such as air conditioners. The effect of the simultaneous partial substitution of Co{sup 2+} for Fe{sup 3+} and of La{sup 3+} for Sr{sup 2+} ion in Sr ferrite on the magnetic properties of anisotropic Sr ferrite magnets was investigated. It was found that the coercive force of Sr ferrite magnets is increased without significant decrease in residual flux density by La-Co substitution. Temperature coefficients of coercive force were found to be also improved by La-Co substitution.

  5. Low temperature synthesis of bismuth ferrite nanoparticles by a ferrioxalate precursor method

    SciTech Connect

    Ghosh, Sushmita; Dasgupta, Subrata . E-mail: sdasgupta@cgcri.res.in; Sen, Amarnath; Maiti, Himadri Sekhar

    2005-12-08

    The synthesis of bismuth ferrite by solid-state reaction of Bi{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} results in the formation of multiphase products. Even coprecipitation followed by calcination leads to the formation of impurity phases. Here, we report the synthesis of magnetoelectric bismuth ferrite by a ferrioxalate precursor method. In this process, bismuth ferrite, synthesized through solutions of some specific salts led to the formation of phase pure (perovskite) nanocrystalline powder (11-22 nm as evident from X-ray diffraction analysis) at a temperature of 600 deg. C. The synthesized powders were characterized by X-ray diffractometry, thermogravimetry and differential thermal analysis, Fourier transformation infrared spectroscopy and scanning electron microscopy. The synthesis route is simple, energy saving and cost-effective. Such nanosized bismuth ferrite powder may have a potential application in making lead free piezoelectric materials for actuators as well as magnetoelectric sensors.

  6. One-pot production of copper ferrite nanoparticles using a chemical method

    NASA Astrophysics Data System (ADS)

    Nishida, Naoki; Amagasa, Shota; Kobayashi, Yoshio; Yamada, Yasuhiro

    2016-12-01

    Copper ferrite nanoparticles were synthesized via the oxidation of precipitates obtained from the reaction of FeCl2, CuSO4 and N2H4 in the presence of gelatin. These copper ferrite particles were subsequently examined using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and Mössbauer spectroscopy. The average size of the copper ferrite nanoparticles was less than 5 nm, and they exhibited superparamagnetic behavior as a result of their small size. The low temperature Mössbauer spectrum exhibited three sets of sextets, two corresponding to the tetrahedral and octahedral sites of the copper spinel structure and one with small hyperfine magnetic field corresponding to the surface or defects of the nanoparticles. When the ratio of copper salt was increased, the tetrahedral site became preferable for copper, and metallic copper and copper ferrite were both present in a single nanoparticle.

  7. Abrasion and deformed layer formation of manganese-zinc ferrite in sliding contact with lapping tapes

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.; Tanaka, K.

    1986-01-01

    Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and the deformed layers produced in single-crystal Mn-Zn ferrite simulated heads during contact with lapping tapes. The crystaline state of the head is changed drastically during the abrasion process. Crystalline states ranging from nearly amorphous to highly textured polycrystalline can be produced on the wear surface of a single-crystal Mn-Zn ferrite head. The total thickness of the deformed layer was approximately 0.8 microns. This thickness increased as the load and abrasive grit size increased. The anisotropic wear of the ferrite was found to be inversely proportional to the hardness of the wear surface. The wear was lower in the order 211 111 10 0110. The wear of the ferrite increased markedly with an increase in sliding velocity and abrasive grit size.

  8. Friction and wear of single-crystal manganese-zinc ferrite

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.

    1979-01-01

    Sliding friction experiments were conducted with single-crystal manganese-zinc ferrite in contact with itself and with transition metals. Results indicate mating highest atomic density directions (110 line type) on matched crystallographic planes exhibit the lowest coefficient of friction indicating that direction is important in the friction behavior of ferrite. Matched parallel high atomic density planes and crystallographic directions at the interface exhibit low coefficients of friction. The coefficients of friction for ferrite in contact with various metals are related to the relative chemical activity of these metals. The more active the metal, the higher the coefficient of friction. Cracking and the formation of hexagon- and rectangular-shaped platelet wear debris due to cleavages are observed on the ferrite surfaces as a result of sliding.

  9. Ferrite-Cored Solenoidal Induction Coil Sensor for BUD (MM-1667)

    SciTech Connect

    Morrison, F.; Becker, A.; Conti, U.; Gasperikova, E.

    2011-06-15

    We have designed and lab tested a new ferrite cored induction coil sensor for measuring the secondary fields from metallic UXO with the BUD system. The objective was to replace the 5-inch diameter air-cored coils in the BUD system with smaller sensors that would allow the placement of multiple sensors in the smaller package of the new BUD hand-held system. A ferrite-cored solenoidal coil of length L can easily be made to have sensitivity and noise level roughly the same as an air-cored coil of a diameter on the same order as L. A ferrite-cored solenoidal coil can easily have a feedback configuration to achieve critical damping. The feedback configuration leads to a very stable response. Feedback ferrite-cored solenoidal coils show very little interaction as long as they are separated by one half their length.

  10. Modelling of Nb influence on phase transformation behaviours from austenite to ferrite in low carbon steels

    NASA Astrophysics Data System (ADS)

    Wang, L.; Parker, S. V.; Rose, A. J.; West, G. D.; Thomson, R. C.

    2016-03-01

    In this paper, a new model has been developed to predict the phase transformation behaviours from austenite to ferrite in Nb-containing low carbon steels. The new model is based on some previous work and incorporates the effects of Nb on phase transformation behaviours, in order to make it applicable for Nb-containing steels. Dissolved Nb atoms segregated at prior austenite grain boundaries increase the critical energy for ferrite nucleation, and thus the ferrite nucleation rate is decreased. Dissolved Nb atoms also apply a solute drag effect to the moving transformation interface, and the ferrite grain growth rate is also decreased. The overall transformation kinetics is then calculated according to the classic Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory. The new model predictions are quite consistent with experimental results for various steels during isothermal transformations or continuous cooling.

  11. Normal and Inverse Ferrite Spinels: A Set of Solid State Chemistry Related Experiments.

    ERIC Educational Resources Information Center

    Chaumont, C.; Burgard, M.

    1979-01-01

    Presents one of the themes of a French chemistry college laboratory course, which concerns the field of solid state chemistry and is focused on the study of the cation distribution in the case of certain spinel ferrites. (HM)

  12. Slow bainite: an opportunity to determine the carbon content of the bainitic ferrite during growth

    SciTech Connect

    Caballero, Francesca G.; Miller, Michael K; Garcia-Mateo, C.

    2011-01-01

    The amount of carbon in solid solution in bainitic ferrite at the early stage of transformation has been directly determined by atom probe tomography at 200 C, taking advantage of the extremely slow transformation kinetics of a novel nanocrystalline steel. Results demonstrated that the original bainitic ferrite retains much of the carbon content of the parent austenite providing strong evidence that bainite transformation is essentially displacive in nature. In this work, the carbon content of the bainitic ferrite away from any carbon-enriched regions has been determined by atom probe tomography as the bainite transformation progresses at 200 C in this nanocrystalline steel. Results provide experimental evidence for the mechanism controlling bainitic ferrite growth in steels.

  13. Low strain, long life creep fatigue of AF2-1DA and INCO 718

    SciTech Connect

    Thakker, A.B.; Cowles, B.A.

    1983-04-01

    Two aircraft turbine disk alloys, GATORIZED AF2-DA and INCO 718 were evaluated for their low strain long life creep-fatigue behavior. Static (tensile and creep rupture) and cyclic properties of both alloys were characterized. The cntrolled strain LCF tests were conducted at 760 C (1400 F) and 649 C (1200 F) for AF2-1DA and INCO 718, respectively. Hold times were varied for tensile, compressive and tensile/compressive strain dwell (relaxation) tests. Stress (creep) hold behavior of AF2-1DA was also evaluated. Generally, INCO 718 exhibited more pronounced reduction in cyclic life due to hold than AF2-1DA. The percent reduction in life for both alloys for strain dwell tests was greater at low strain ranges (longer life regime). Changing hold time from 0 to 0.5, 2.0 and 15.0 min. resulted in corresponding reductions in life. The continuous cycle and cyclic/dwell initiation failure mechanism was predominantly transgranular for AF2-1DA and intergranular for INCO 718.

  14. A simple web-based tool to compare freshwater fish data collected using AFS standard methods

    USGS Publications Warehouse

    Bonar, Scott A.; Mercado-Silva, Norman; Rahr, Matt; Torrey, Yuta T.; Cate, Averill, Jr.

    2016-01-01

    The American Fisheries Society (AFS) recently published Standard Methods for Sampling North American Freshwater Fishes. Enlisting the expertise of 284 scientists from 107 organizations throughout Canada, Mexico, and the United States, this text was developed to facilitate comparisons of fish data across regions or time. Here we describe a user-friendly web tool that automates among-sample comparisons in individual fish condition, population length-frequency distributions, and catch per unit effort (CPUE) data collected using AFS standard methods. Currently, the web tool (1) provides instantaneous summaries of almost 4,000 data sets of condition, length frequency, and CPUE of common freshwater fishes collected using standard gears in 43 states and provinces; (2) is easily appended with new standardized field data to update subsequent queries and summaries; (3) compares fish data from a particular water body with continent, ecoregion, and state data summaries; and (4) provides additional information about AFS standard fish sampling including benefits, ongoing validation studies, and opportunities to comment on specific methods. The web tool—programmed in a PHP-based Drupal framework—was supported by several AFS Sections, agencies, and universities and is freely available from the AFS website and fisheriesstandardsampling.org. With widespread use, the online tool could become an important resource for fisheries biologists.

  15. GLA-AF, an emulsion-free vaccine adjuvant for pandemic influenza.

    PubMed

    Clegg, Christopher H; Roque, Richard; Perrone, Lucy A; Rininger, Joseph A; Bowen, Richard; Reed, Steven G

    2014-01-01

    The ongoing threat from Influenza necessitates the development of new vaccine and adjuvant technologies that can maximize vaccine immunogenicity, shorten production cycles, and increase global vaccine supply. Currently, the most successful adjuvants for Influenza vaccines are squalene-based oil-in-water emulsions. These adjuvants enhance seroprotective antibody titers to homologous and heterologous strains of virus, and augment a significant dose sparing activity that could improve vaccine manufacturing capacity. As an alternative to an emulsion, we tested a simple lipid-based aqueous formulation containing a synthetic TLR4 ligand (GLA-AF) for its ability to enhance protection against H5N1 infection. GLA-AF was very effective in adjuvanting recombinant H5 hemagglutinin antigen (rH5) in mice and was as potent as the stable emulsion, SE. Both adjuvants induced similar antibody titers using a sub-microgram dose of rH5, and both conferred complete protection against a highly pathogenic H5N1 challenge. However, GLA-AF was the superior adjuvant in ferrets. GLA-AF stimulated a broader antibody response than SE after both the prime and boost immunization with rH5, and ferrets were better protected against homologous and heterologous strains of H5N1 virus. Thus, GLA-AF is a potent emulsion-free adjuvant that warrants consideration for pandemic influenza vaccine development. PMID:24551202

  16. Low strain, long life creep fatigue of AF2-1DA and INCO 718

    NASA Technical Reports Server (NTRS)

    Thakker, A. B.; Cowles, B. A.

    1983-01-01

    Two aircraft turbine disk alloys, GATORIZED AF2-DA and INCO 718 were evaluated for their low strain long life creep-fatigue behavior. Static (tensile and creep rupture) and cyclic properties of both alloys were characterized. The cntrolled strain LCF tests were conducted at 760 C (1400 F) and 649 C (1200 F) for AF2-1DA and INCO 718, respectively. Hold times were varied for tensile, compressive and tensile/compressive strain dwell (relaxation) tests. Stress (creep) hold behavior of AF2-1DA was also evaluated. Generally, INCO 718 exhibited more pronounced reduction in cyclic life due to hold than AF2-1DA. The percent reduction in life for both alloys for strain dwell tests was greater at low strain ranges (longer life regime). Changing hold time from 0 to 0.5, 2.0 and 15.0 min. resulted in corresponding reductions in life. The continuous cycle and cyclic/dwell initiation failure mechanism was predominantly transgranular for AF2-1DA and intergranular for INCO 718.

  17. Effect of X irradiation on optical properties of Teflon-AF

    NASA Astrophysics Data System (ADS)

    Jahan, M. S.; Ermer, D. R.; Cooke, D. W.

    1993-03-01

    Radiation effects in optical-grade amorphous fluoropolymer, Teflon-AF, is investigated by UV-visible absorption and electron spin resonance (ESR) measurements. When irradiated with low-energy (40 kVp) X-rays at room temperature in air, Teflon-AF is found to develop a broad, structureless UV-absorption band in the wavelength interval 200-350 nm. While the UV absorption increases as a function of X-ray dose, with relative rates of approx 2 × 10 -5 Gy -1 (1 × 10 -5 Gy -1) in Teflon-AF 1600 (Teflon-AF 2400), its optical transparency for a given dose of 67.5 kGy, however, remains unaffected. Additional measurements conducted using electron spin resonance (ESR) technique reveal that the observed UV absorption is caused by the X-ray induced peroxy radical (POO .˙). The results also suggest that the inclusion of dioxole monomer in the PTFE chain not only improves the optical clarity of Teflon-AF, as reported, but also increases its radiation tolerance. During a post-irradiation storage in air at RT for about 30 days the peroxy radical is observed to decay, with a concomitant decrease in UV absorption. A tentative model is proposed to explain the radiation damage and recovery mechanisms.

  18. The antitumor effect of locoregional magnetic cobalt ferrite in dog mammary adenocarcinoma

    NASA Astrophysics Data System (ADS)

    Şincai, Mariana; Gângǎ, Diana; Bica, Doina; Vékás, Ladislau

    2001-01-01

    The endocytosis of nanosized magnetic particles by tumor cells led to numerous tests to establish the use of this phenomenon in antitumor therapy. The direct antitumor effect of a biocompatible cobalt-ferrite-based magnetic fluid directly inoculated in bitch mammary tumors was studied. A direct correlation between tumor cell lysis and cobalt ferrite was established in tumors. Massive endocytosis of magnetic particles was observed 1 h after the contact of magnetic fluid with tumor cells.

  19. Decomposition Kinetics of Ferrite in Isothermally Aged SAF 2507-Type Duplex Stainless Steel

    NASA Astrophysics Data System (ADS)

    Berecz, Tibor; Fazakas, Éva; Mészáros, István; Sajó, István

    2015-12-01

    Decomposition of the ferritic phase is studied in isothermally aged SAF 2507 superduplex stainless steel (SDSS) by means of different examination methods. The ferritic phase ( δ) undergoes an eutectoid transformation into secondary austenite ( γ 2) and σ-phase between 650 and 1000 °C. Samples were treated at 900 °C because the incubation time of this transformation is the shortest at this temperature. In order to follow the microstructural changes, x-ray diffraction analysis (XRD), automated electron backscatter diffraction (EBSD), applied magnetic investigation [vibrating sample magnetometer (VSM)], micro-hardness tests, and differential thermal analysis (DTA) were used. The results of XRD and EBSD methods for phase quantification showed nearly the same amounts for all three phases. The results of applied magnetic investigation for the fraction of ferritic phase were also in good agreement with the corresponding results of XRD and EBSD methods. Decomposition of ferrite is similarly well-traceable on EBSD phase maps where the coherent ferritic areas gradually broke into pieces with increasing time of heat treatment. According to the EBSD measurements the σ-phase grains appeared and started to grow after 2 min aging time in the ferritic-austenitic matrix, usually on the boundaries of ferritic and austenitic grains. After 15 min treating time, the microstructure consisted of mainly σ- and austenitic (primary and secondary) phases with negligible amount of ferrite. Chemical composition of the σ-phase was measured by energy-dispersive x-ray spectroscopy (EDS) at different aging times. Activation energies of σ-phase precipitation and α'-phase formation were determined by the Kissinger plot, through DTA measurements; they are 243 and 261 kJ/mol, respectively. Using the results of phase quantifications, the Johnson-Mehl-Avrami equation was fitted.

  20. Quantitative metallographic method for determining delta ferrite content in austenitic stainless steels. Final report

    SciTech Connect

    Pressly, G.A.

    1986-01-01

    Delta ferrite is a magnetic form of iron and has a body centered cubic crystal structure. It is often present as a nonequilibrium phase in austenitic stainless steel welds, castings, and wrought materials. The ferrite content of austenitic stainless steel can directly affect its properties, especially weldability and formability. Therefore, it is highly desirable to be able to predict and/or measure the ferrite content accurately. Current magnetic ferrite measuring methods are not applicable when test materials are geometrically small (less than 2.54 mm thick and 6.35 mm wide). Therefore, a standard metallographic test method STM 00107-A was established to determine delta ferrite content in small weldments and base metals of austenitic stainless steel. This standard test method (STM 00107-A) was then performed on several exemplary metallographic specimens to illustrate its capabilities and applications. The results from the exemplary tests were compared and contrasted to metallographic manual point count measurements, Ferritescope measurements, and predicted values calculated from chemical analyses. By utilizing the manual metallographic point count data, an accuracy of +-16% and a precision of +-0.77% were determined for the standard test method. The comparison of Ferritescope data to standard test method revealed that the results obtained by the two methods are close at low (0 to 3%) ferrite contents and Ferritscope results are substantially greater at higher (6 to 10%) ferrite contents. The standard test method data compiled from the exemplary weld specimens was noted to be very similar to the predicted values calculated from chemical analyses. It was also shown that because the standard test method utilizes optics the morphology of the delta ferrite particles can be determined. This type of determination is possible only with metallographic methods.

  1. Study of mechanical behavior and internal structure of ferritic nanocrystalline material

    SciTech Connect

    Weertman, J.R.; Murphy, W.P.

    1992-08-01

    The research thrust of this grant has been directed into two areas. The principal effort has been spent in an investigation of the synthesis, mechanical behavior and internal structure of ferritic nanocrystalline material. A second effort involves a study of the high temperature behavior of several ferritic steels. In particular, we are investigating the precursors and earliest stages of fatigue crack initiation, especially how initiation is affected by hold times and by environment.

  2. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    DOEpatents

    Park, Jong-Hee; Natesan, Krishnamurti; Rink, David L.

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  3. Chromium and copper substituted lanthanum nano-ferrites: Their synthesis, characterization and application studies

    NASA Astrophysics Data System (ADS)

    Jauhar, Sheenu; Singhal, Sonal

    2014-10-01

    Nano-crystalline lanthanum ferrites substituted by chromium and copper having formula LaMxFe1-xO3 (M = Cr, Cu; 0.0 ⩽ x ⩽ 0.5) were synthesized using sol-gel auto-combustion method. The formation of ferrite particles was confirmed using Fourier Transform Infra-Red (FT-IR) spectra and powder X-ray Diffraction (XRD) techniques. The entire ferrite compositions were found to be pure phased with same symmetry as LaFeO3. The average crystallite size was calculated to be ∼60 nm. The ferrite compositions were observed to behave as semi-conductors, as their resistivity decreased with increasing temperature. These ferrite compositions were employed as catalysts in the decomposition of hydrogen peroxide solution (0.17 M). Pure LaFeO3 was found to have a very low catalytic activity towards the decomposition of hydrogen peroxide solution, while presence of copper in the lanthanum ferrite lattice was found to significantly enhance its catalytic activity. The rate constant in case of reactions catalysed by LaCu0.5Fe0.5O3 was nearly 25 times larger than that obtained from reactions catalysed by pure LaFeO3. However, chromium substitution was not found to influence the catalytic activity of lanthanum ferrites as chromium substituted lanthanum ferrites exhibited very low catalytic activity. This was explained on the basis of relative stability of oxidation states of the substituent ions and the presence of defects in the crystal lattice.

  4. Stability of Y Ti O Precipitates in Friction Stir Welded Nanostructured Ferritic Alloys

    DOE PAGESBeta

    Yu, Xinghua; Mazumder, Baishakhi; Miller, Michael K; David, Stan A; Feng, Zhili

    2015-01-01

    Nanostructured ferritic alloys (NFAs), which have complex microstructures consisting of ultrafine ferritic grains with a dispersion of stable oxide particles and nanoclusters (NC), are promising materials for fuel cladding and structural applications in the next generation nuclear reactor. This study evaluates microstructure of friction stir welded NFA using electron microscopy and atom probe tomography (APT) techniques. APT results revealed NCs are coarsened and inhomogeneously distributed in the stir zone. Three hypotheses on coarsening of NC are presented.

  5. Effect of tetra ionic substitution on the dielectric properties of Cu-ferrite

    NASA Astrophysics Data System (ADS)

    Mazen, S. A.; Zaki, H. M.

    2003-09-01

    X-ray diffraction (XRD), of the two systems of mixed ferrites Cu1+xTixFe2-2xO4 (where x = 0.0, 0.1, 0.2, 0.3, and 0.4); indicates that the samples of x = 0 (CuFe2O4) and x = 0.1 of the Cu-Ti system were formed in tetragonal structure and all other samples of the two system were formed in the cubic system.The ac conductivity , dielectric constant , dielectric loss and the loss tangent tan δ were determined against frequency at room temperature for Cu-Ge and Cu-Ti ferrites. The measurements of and tan δ were performed over a wide range of frequency and temperature.The Maxwell-Wagner model was applied to analyze the dielectric properties of the investigated systems, according to which the dielectric parameters such as the relaxation time . A value of 1 = 5 × 10-7 s was found for Cu-Ge ferrite and 2 = 1.85 × 10-6 s for Cu-Ti ferrites. The hopping rate (g) was found to be 2 × 106 s-1 and 5.4 × 105 s-1 for the two systems Cu-Ge and Cu-Ti ferrites, respectively.The conduction of the two-ferrite systems was discussed on the basis of the hopping mechanism. The activation energy for conduction was calculated and found in the range of 0.27-0.39 eV for Cu-Ge ferrite and 0.21-0.30 eV for Cu-Ti ferrite. (

  6. Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

    PubMed Central

    Washington, Erica J.; Mukhtar, M. Shahid; Finkel, Omri M.; Wan, Li; Kieber, Joseph J.; Dangl, Jeffery L.

    2016-01-01

    HopAF1 is a type III effector protein of unknown function encoded in the genomes of several strains of Pseudomonas syringae and other plant pathogens. Structural modeling predicted that HopAF1 is closely related to deamidase proteins. Deamidation is the irreversible substitution of an amide group with a carboxylate group. Several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. We identified Arabidopsis methylthioadenosine nucleosidase proteins MTN1 and MTN2 as putative targets of HopAF1 deamidation. MTNs are enzymes in the Yang cycle, which is essential for the high levels of ethylene biosynthesis in Arabidopsis. We hypothesized that HopAF1 inhibits the host defense response by manipulating MTN activity and consequently ethylene levels. We determined that bacterially delivered HopAF1 inhibits ethylene biosynthesis induced by pathogen-associated molecular patterns and that Arabidopsis mtn1 mtn2 mutant plants phenocopy the effect of HopAF1. Furthermore, we identified two conserved asparagines in MTN1 and MTN2 from Arabidopsis that confer loss of function phenotypes when deamidated via site-specific mutation. These residues are potential targets of HopAF1 deamidation. HopAF1-mediated manipulation of Yang cycle MTN proteins is likely an evolutionarily conserved mechanism whereby HopAF1 orthologs from multiple plant pathogens contribute to disease in a large variety of plant hosts. PMID:27274076

  7. A Critical Role for CRM1 in Regulating HOXA Gene Transcription in CALM-AF10 Leukemias

    PubMed Central

    Conway, Amanda E.; Haldeman, Jonathan M.; Wechsler, Daniel S.; Lavau, Catherine P.

    2014-01-01

    The leukemogenic CALM-AF10 fusion protein is found in patients with immature acute myeloid and T-lymphoid malignancies. CALM-AF10 leukemias display abnormal H3K79 methylation and increased HOXA cluster gene transcription. Elevated expression of HOXA genes is critical for leukemia maintenance and progression; however, the precise mechanism by which CALM-AF10 alters HOXA gene expression is unclear. We previously determined that CALM contains a CRM1-dependent nuclear export signal (NES), which is both necessary and sufficient for CALM-AF10-mediated leukemogenesis. Here, we find that interaction of CALM-AF10 with the nuclear export receptor CRM1 is necessary for activating HOXA gene expression. We show that CRM1 localizes to HOXA loci where it recruits CALM-AF10, leading to transcriptional and epigenetic activation of HOXA genes. Genetic and pharmacological inhibition of the CALM-CRM1 interaction prevents CALM-AF10 enrichment at HOXA chromatin, resulting in immediate loss of transcription. These results provide a comprehensive mechanism by which the CALM-AF10 translocation activates the critical HOXA cluster genes. Furthermore, this report identifies a novel function of CRM1: the ability to bind chromatin and recruit the NES-containing CALM-AF10 transcription factor. PMID:25027513

  8. An Evaluation of the Impacts of AF-M315E Propulsion Systems for Varied Mission Applications

    NASA Technical Reports Server (NTRS)

    Deans, Matthew C.; Oleson, Steven R.; Fittje, James; Colozza, Anthony; Packard, Tom; Gyekenyesi, John; McLean, Christopher H.; Spores, Ronald A.

    2015-01-01

    The purpose of the AF-M315E COMPASS study is to identify near-term (3-5 years) and long term (5 years +) opportunities for infusion, specifically the thruster and associated component technologies being developed as part of the GPIM project. Develop design reference missions which show the advantages of the AF-M315E green propulsion system. Utilize a combination of past COMPASS designs and selected new designs to demonstrate AF-M315E advantages. Use the COMPASS process to show the puts and takes of using AF-M315E at the integrated system level.

  9. AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis.

    PubMed

    Park, Jino; Schlederer, Michaela; Schreiber, Martin; Ice, Ryan; Merkel, Olaf; Bilban, Martin; Hofbauer, Sebastian; Kim, Soojin; Addison, Joseph; Zou, Jie; Ji, Chunyan; Bunting, Silvia T; Wang, Zhengqi; Shoham, Menachem; Huang, Gang; Bago-Horvath, Zsuzsanna; Gibson, Laura F; Rojanasakul, Yon; Remick, Scot; Ivanov, Alexey; Pugacheva, Elena; Bunting, Kevin D; Moriggl, Richard; Kenner, Lukas; Tse, William

    2015-08-21

    AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent "metastatic founder cells" which have invasive properties. PMID:26079538

  10. AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis

    PubMed Central

    Park, Jino; Schlederer, Michaela; Schreiber, Martin; Ice, Ryan; Merkel, Olaf; Bilban, Martin; Hofbauer, Sebastian; Kim, Soojin; Addison, Joseph; Zou, Jie; Ji, Chunyan; Bunting, Silvia T.; Wang, Zhengqi; Shoham, Menachem; Huang, Gang; Bago-Horvath, Zsuzsanna; Gibson, Laura F.; Rojanasakul, Yon; Remick, Scot; Ivanov, Alexey; Pugacheva, Elena; Bunting, Kevin D.; Moriggl, Richard

    2015-01-01

    AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent “metastatic founder cells” which have invasive properties. PMID:26079538

  11. Outcomes registry for better informed treatment of atrial fibrillation II: Rationale and design of the ORBIT-AF II registry

    PubMed Central

    Steinberg, Benjamin A.; Blanco, Rosalia G.; Ollis, Donna; Kim, Sunghee; Holmes, DaJuanicia N.; Kowey, Peter R.; Fonarow, Gregg C.; Ansell, Jack; Gersh, Bernard; Go, Alan S.; Hylek, Elaine; Mahaffey, Kenneth W.; Thomas, Laine; Chang, Paul; Peterson, Eric D.; Piccini, Jonathan P.

    2014-01-01

    Background Recent clinical trials have demonstrated the safety and efficacy of several non–vitamin K oral anticoagulants (NOACs) for the treatment of atrial fibrillation (AF). However, there are limited data on their use and outcomes in routine clinical practice, particularly among patients newly diagnosed as having AF and patients with AF recently transitioned to a NOAC. Methods/Design ORBIT-AF II is a multicenter, national registry of patients with AF that is enrolling up to 15,000 newly diagnosed patients with AF and/or those with AF recently transitioned to a NOAC from 300 US outpatient practices. These patients will be followed for up to 2 years, including clinical status, outcomes (major adverse cardiovascular events, bleeding), and management of anticoagulation surrounding bleeding events. In addition, detailed data regarding the use of these agents in and around cardiac procedures, their complications, and management of such complications will be collected. Conclusions The ORBIT-AF II registry will provide valuable insights into the safety and effectiveness of NOACs used in AF in community practice settings. PMID:25066554

  12. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  13. Thermodynamic and Kinetic Studies for Intensifying Selective Decomposition of Zinc Ferrite

    NASA Astrophysics Data System (ADS)

    Han, Junwei; Liu, Wei; Qin, Wenqing; Jiao, Fen; Wang, Dawei; Liang, Chao

    2016-01-01

    A novel method to intensify the selective decomposition of zinc ferrite by a roasting process including reduction and magnetization stages was proposed. The relevant thermodynamic analysis with HSC [enthalpy (H), entropy (S) and heat capacity (C)] Chemistry 5.0 and experimental research on a laboratory scale were investigated. The thermodynamic calculations show that increasing the temperature and the CO amount promote not only the decomposition of zinc ferrite but also the formation of wustite, which can be converted to magnetite using sufficient CO2 at 823 K. The experimental results indicate that the zinc ferrite was decomposed into zinc oxide and wustite by reduction roasting under a gas mixture of 20% CO, 20% CO2 and 60% N2 at 1023 K for 90 min, and the decomposition degree of zinc ferrite reached 94%. Then, the generated wustite was transformed into magnetite by magnetization roasting under CO2 atmosphere at 823 K for 75 min, after which the selective extraction of zinc from zinc ferrite could be well achieved by low acid leaching. Increasing temperature and time were conducive to the magnetization within low temperature range, but when the temperature was above 823 K the zinc ferrite could be regenerated.

  14. Effect of Er doping on the structural and magnetic properties of cobalt-ferrite

    SciTech Connect

    Prathapani, Sateesh; Vinitha, M.; Das, D.; Jayaraman, T. V.

    2014-05-07

    Nanocrystalline particulates of Er doped cobalt-ferrites CoFe{sub (2−x)}Er{sub x}O{sub 4} (0 ≤ x ≤ 0.04), were synthesized, using sol-gel assisted autocombustion method. Co-, Fe-, and Er- nitrates were the oxidizers, and malic acid served as a fuel and chelating agent. Calcination (400–600 °C for 4 h) of the precursor powders was followed by sintering (1000 °C for 4 h) and structural and magnetic characterization. X-ray diffraction confirmed the formation of single phase of spinel for the compositions x = 0, 0.01, and 0.02; and for higher compositions an additional orthoferrite phase formed along with the spinel phase. Lattice parameter of the doped cobalt-ferrites was higher than that of pure cobalt-ferrite. The observed red shift in the doped cobalt-ferrites indicates the presence of induced strain in the cobalt-ferrite matrix due to large size of the Er{sup +3} compared to Fe{sup +3}. Greater than two-fold increase in coercivity (∼66 kA/m for x = 0.02) was observed in doped cobalt-ferrites compared to CoFe{sub 2}O{sub 4} (∼29 kA/m)

  15. Residual Ferrite and Relationship Between Composition and Microstructure in High-Nitrogen Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Wang, Qingchuan; Ren, Yibin; Yao, Chunfa; Yang, Ke; Misra, R. D. K.

    2015-12-01

    A series of high-nitrogen stainless steels (HNS) containing δ-ferrite, which often retained in HNS, were studied to establish the relationship between composition and microstructure. Both ferrite and nitrogen depletions were found in the center regions of cast ingots, and the depletion of nitrogen in that area was found to be the main reason for the existence of δ-ferrite. Because of the existence of heterogeneity, the variation of microstructure with nitrogen content was detected. Hence, the critical contents of nitrogen (CCN) for the fully austenitic HNS were obtained. Then the effects of elements such as N, Cr, Mn, and Mo on austenite stability were investigated via thermodynamic calculations. The CCN of HNS alloys were also obtained by calculations. Comparing the CCN obtained from experiment and calculation, it was found that the forged microstructure of the HNS was close to the thermodynamic equilibrium. To elucidate the above relationship, by regression analysis using calculated thermodynamic data, nitrogen equivalent and a new constitution diagram were proposed. The constitution diagram accurately distinguishes the austenitic single-phase region and the austenite + ferrite dual-phase region. The nitrogen equivalent and the new constitution diagram can be used for alloying design and microstructural prediction in HNS. According to the nitrogen equivalent, the ferrite stabilizing ability of Mo is weaker than Cr, and with Mn content increases, Mn behaves as a weak austenite stabilizer first and then as a ferrite stabilizer.

  16. Synthesis of magnetic nickel spinel ferrite nanospheres by a reverse emulsion-assisted hydrothermal process

    SciTech Connect

    Zhang Jilin; Shi Jianxin; Gong Menglian

    2009-08-15

    Nickel ferrite nanospheres were successfully synthesized by a reverse emulsion-assisted hydrothermal method. The reverse emulsion was composed of water, cetyltrimethyl ammonium bromide, polyoxyethylene(10)nonyl phenyl ether, iso-amyl alcohol and hexane. During the hydrothermal process, beta-FeO(OH) and Ni{sub 0.75}Fe{sub 0.25}(CO{sub 3}){sub 0.125}(OH){sub 2}.0.38H{sub 2}O (INCHH) nanorods formed first and then transformed into nickel spinel ferrite nanospheres. The phase transformation mechanism is proposed based on the results of X-ray powder diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy, etc. Nickel ferrite may form at the end of the INCHH nanorods or from the solution accompanied by the dissolution of beta-FeO(OH) and INCHH nanorods. The X-ray photoelectron spectroscopy analysis shows that a few Fe{sup 3+} ions have been reduced to Fe{sup 2+} ions during the formation of nickel ferrite. The maximum magnetization of the nickel ferrite nanospheres obtained after hydrothermal reaction for 30 h is 55.01 emu/g, which is close to that of bulk NiFe{sub 2}O{sub 4}. - Graphical abstract: Nickel ferrite nanospheres were obtained through a reverse emulsion-assisted hydrothermal process. The phase transformation as a function of reaction time was studied based on the XRD, TEM and EDS analyses.

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

    SciTech Connect

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

    2013-12-16

    This paper investigates the magnetic and structural properties of iron-based soft magnetic composites coated with silicone-MnZn ferrite hybrid. The organic silicone resin was added to improve the flexibility of the insulated iron powder and causes better adhesion between particles to increase the mechanical properties. Scanning electron microscopy and distribution maps show that the iron particle surface is covered with a thin layer of silicone-MnZn ferrite. Silicone-MnZn ferrite coated samples have higher permeability when compared with the non-magnetic silicone resin coated compacts. The real part of permeability increases by 34.18% when compared with the silicone resin coated samples at 20 kHz. In this work, a formula for calculating the total loss component by loss separation method is presented and finally the different parts of total losses are calculated. The results show that the eddy current loss coefficient is close to each other for the silicone-MnZn ferrite, silicone resin and MnZn ferrite coated samples (0.0078ferrite coated sample (k{sub 2} =1.4058) in comparison with other samples.

  18. Transformation Characteristics of Ferrite/Carbide Aggregate in Continuously Cooled, Low Carbon-Manganese Steels

    NASA Astrophysics Data System (ADS)

    Di Martino, S. F.; Thewlis, G.

    2014-02-01

    Transformation characteristics and morphological features of ferrite/carbide aggregate (FCA) in low carbon-manganese steels have been investigated. Work shows that FCA has neither the lamellae structure of pearlite nor the lath structure of bainite and martensite. It consists of a fine dispersion of cementite particles in a smooth ferrite matrix. Carbide morphologies range from arrays of globular particles or short fibers to extended, branched, and densely interconnected fibers. Work demonstrates that FCA forms over similar cooling rate ranges to Widmanstätten ferrite. Rapid transformation of both phases occurs at temperatures between 798 K and 973 K (525 °C and 700 °C). FCA reaction is not simultaneous with Widmanstätten ferrite but occurs at temperatures intermediate between Widmanstätten ferrite and bainite. Austenite carbon content calculations verify that cementite precipitation is thermodynamically possible at FCA reaction temperatures without bainite formation. The pattern of precipitation is confirmed to be discontinuous. CCT diagrams have been constructed that incorporate FCA. At low steel manganese content, Widmanstätten ferrite and bainite bay sizes are significantly reduced so that large amounts of FCA are formed over a wide range of cooling rates.

  19. Modeling the Ferrite-Austenite Transformation in the Heat-Affected Zone of Stainless Steel Welds

    SciTech Connect

    Vitek, J.M.; David, S.A.

    1997-12-01

    The diffusion-controlled ferrite-austenite transformation in stainless steel welds was modeled. An implicit finite-difference analysis that considers multi-component diffusion was used. The model was applied to the Fe-Cr-Ni system to investigate the ferrite- austenite transformation in the heat-affected zone of stainless steel weld metal. The transformation was followed as a function of time as the heat-affected zone was subjected to thermal cycles comparable to those experienced during gas-tungsten arc welding. The results showed that the transformation behavior and the final microstructural state are very sensitive to the maximum temperature that is experienced by the heat-affected zone. For high maximum exposure temperatures ({approximately} 1300{degree} C), the ferrite formation that occurs at the highest temperatures is not completely offset by the reverse ferrite dissolution at lower temperatures. As a result, for high temperature exposures there is a net increase in the amount of ferrite in the microstructure. It was also found that if compositional gradients are present in the initial ferrite and austenite phases, the extent of the transformation is impacted.

  20. Ferrous sulfate based low temperature synthesis and magnetic properties of nickel ferrite nanostructures

    SciTech Connect

    Tejabhiram, Y.; Pradeep, R.; Helen, A.T.; Gopalakrishnan, C.; Ramasamy, C.

    2014-12-15

    Highlights: • Novel low temperature synthesis of nickel ferrite nanoparticles. • Comparison with two conventional synthesis techniques including hydrothermal method. • XRD results confirm the formation of crystalline nickel ferrites at 110 °C. • Superparamagnetic particles with applications in drug delivery and hyperthermia. • Magnetic properties superior to conventional methods found in new process. - Abstract: We report a simple, low temperature and surfactant free co-precipitation method for the preparation of nickel ferrite nanostructures using ferrous sulfate as the iron precursor. The products obtained from this method were compared for their physical properties with nickel ferrites produced through conventional co-precipitation and hydrothermal methods which used ferric nitrate as the iron precursor. X-ray diffraction analysis confirmed the synthesis of single phase inverse spinel nanocrystalline nickel ferrites at temperature as low as 110 °C in the low temperature method. Electron microscopy analysis on the samples revealed the formation of nearly spherical nanostructures in the size range of 20–30 nm which are comparable to other conventional methods. Vibrating sample magnetometer measurements showed the formation of superparamagnetic particles with high magnetic saturation 41.3 emu/g which corresponds well with conventional synthesis methods. The spontaneous synthesis of the nickel ferrite nanoparticles by the low temperature synthesis method was attributed to the presence of 0.808 kJ mol{sup −1} of excess Gibbs free energy due to ferrous sulfate precursor.

  1. Synthesis, structure and electromagnetic properties of Mn-Zn ferrite by sol-gel combustion technique

    NASA Astrophysics Data System (ADS)

    Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

    2014-01-01

    The electromagnetic absorbing behaviors of a thin coating fabricated by mixing Mn-Zn ferrite with epoxy resin (EP) were studied. The spinel ferrites Mn1-xZnxFe2O4 (x=0.2, 0.5 and 0.8) were synthesized with citrate acid as complex agent by sol-gel combustion method. The microstructure and surface morphology of Mn-Zn ferrite powders were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The complex permittivity and complex permeability of the fabricated ferrite/EP composites were investigated in terms of their contributions to the absorbing properties in the low frequency (10 MHz to 1 GHz). The microwave absorption of the prepared ferrite/EP composites could be tailored by matching the dielectric loss and magnetic loss and by controlling the doped metal ratio. The composites with the ferrite composition x=0.2 are found to show higher reflection loss compared with the composites with other compositions. It is proposed that the prepared composites can potentially be applied in electromagnetic microwave absorbing field.

  2. Effects of Heat Treatment on the Microstructure and Mechanical Properties of Low-Carbon Steel with Magnesium-Based Inclusions

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Feng, Pei-Hsien; Pan, Yan-Chi; Hwang, Weng-Sing; Su, Yen-Hao; Lu, Muh-Jung

    2016-08-01

    The effects of heat treatment on the microstructure and mechanical properties of Mg-containing (7 ppm), low-carbon commercial steel (SS400) were investigated. Twenty different heat treatment paths were performed using a Gleeble 1500 thermomechanical simulator. It was observed by using an optical microscope that as the cooling rate increased and holding temperature decreased, the volume fractions of pearlite, Widmanstätten ferrite, and grain boundary allotriomorphs ferrite fell, whereas that of acicular ferrite (AF) increased. Quantifying the fractions of AF and other phases by using electron backscatter diffraction shows that the heat treatment path with a cooling rate of 20 K/s and holding temperature of 723 K (450 °C) induced the highest volume fraction (44 pct) of AF. As such, the toughness of the sample was increased 12.4 times compared with that observed in the sample containing 4 pct AF. Typical inclusions were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy. The results showed that the magnesium-based complex inclusions could act as nucleation sites of AF. Inclusions with a size of about 5 μm can serve as heterogeneous nucleation sites for AF. Mg-containing SS400 steel also has excellent hot-ductility in the temperature range of 973 K to 1273 K (700 °C to 1000 °C), and the minimum percentage reduction in area (R.A pct) value of around 63 pct at 1073 K (800 °C).

  3. Design and position control of AF lens actuator for mobile phone using IPMC-EMIM

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Joo; Kim, Chul-Jin; Park, No-Cheol; Yang, Hyun-Seok; Park, Young-Pil; Park, Kang-Ho; Lee, Hyung-Kun; Choi, Nak-Jin

    2008-03-01

    IPMC-EMIM (Ionic Polyer Metal Composites + 1-ethyl-3- methyl imidazolium trifluromethane sulfonate, EMIM-Tfo) is fabricated by substituting ionic liquid for water in Nafion film, which improves water sensitiveness of IPMC and guarantees uniform performance regardless of the surrounding environment. In this paper, we will briefly introduce the procedure of fabrication of IPMC-EMIM and proceed to introduce the Hook-type actuator using IPMC-EMIM and application to AF Lens actuator. Parameters of Hook-type actuator are estimated from experimental data. In the simulation, The proposed AF Lens Actuator is assumed to be a linear system and based on estimated parameters, PID controller will be designed and controlled motion of AF Lens actuator will be shown through simulation.

  4. Cloning and characterization of two duplicated interleukin-17A/F2 genes in common carp (Cyprinus carpio L.): Transcripts expression and bioactivity of recombinant IL-17A/F2.

    PubMed

    Li, Hongxia; Yu, Juhua; Li, Jianlin; Tang, Yongkai; Yu, Fan; Zhou, Jie; Yu, Wenjuan

    2016-04-01

    Interleukin-17 (IL-17) plays an important role in inflammation and host defense in mammals. In this study, we identified two duplicated IL-17A/F2 genes in the common carp (Cyprinus carpio) (ccIL-17A/F2a and ccIL-17A/F2b), putative encoded proteins contain 140 amino acids (aa) with conserved IL-17 family motifs. Expression analysis revealed high constitutive expression of ccIL-17A/F2s in mucosal tissues, including gill, skin and intestine, their expression could be induced by Aeromonas hydrophila, suggesting a potential role in mucosal immunity. Recombinant ccIL-17A/F2a protein (rccIL-17A/F2a) produced in Escherichia coli could induce the expression of proinflammatory cytokines (IL-1β) and the antimicrobial peptides S100A1, S100A10a and S100A10b in the primary kidney in a dose- and time-dependent manner. Above findings suggest that ccIL-17A/F2 plays an important role in both proinflammatory and innate immunity. Two duplicated ccIL-17A/F2s showed different expression level with ccIL-17A/F2a higher than b, comparison of two 5' regulatory regions indicated the length from anticipated promoter to transcriptional start site (TSS) and putative transcription factor binding site (TFBS) were different. Promoter activity of ccIL-17A/F2a was 2.5 times of ccIL-17A/F2b which consistent with expression results of two genes. These suggest mutations in 5'regulatory region contributed to the differentiation of duplicated genes. To our knowledge, this is the first report to analyze 5'regulatory region of piscine IL-17 family genes. PMID:26921542

  5. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    NASA Astrophysics Data System (ADS)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-04-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  6. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    NASA Astrophysics Data System (ADS)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-06-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  7. A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy.

    PubMed

    Gazder, Azdiar A; Al-Harbi, Fayez; Spanke, Hendrik Th; Mitchell, David R G; Pereloma, Elena V

    2014-12-01

    Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth. PMID:25126753

  8. Compliance testing of the Clear AFS Power Plant, coal-fired boiler 1, Clear AFS, Alaska. Final report, 18-23 April 1989

    SciTech Connect

    Scott, P.T.

    1989-10-01

    The 13 MWS/DE through HQ AFSPACECOM/SG requested AFOEHL Quality Function conduct source emission testing of the Clear AFS Power Plant to determine compliance with applicable Alaska Air Quality Control Codes. The Alaska Department of Environmental Conservation required testing of one representative boiler for permit compliance and to determine operating limitations for each boiler. At 80,000 lbs steam/hour particulate emission were within emission limits allowed by the State of Alaska.

  9. 27. "SITE PLAN." Specifications No. OC15775, Drawing No. AF600915, sheet ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. "SITE PLAN." Specifications No. OC1-57-75, Drawing No. AF-60-09-15, sheet 1 of 96, D.O. Series No. AF 1394/20, Rev. B. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 5296 Rev. B, Date: 11/17/59. Site plan of 20,000-foot track, including construction phasing notes. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  10. Multi-object spectroscopy data reduction: the AF2+WYFFOS pipeline

    NASA Astrophysics Data System (ADS)

    Domínquez Palmero, Lilian; Jackson, Richard; Molaeinezhad, Alireza; Fariña, Cecilia; Balcells, Marc; Benn, Chris R.

    2014-08-01

    The scientific productivity of complex instrumentation strongly depends on the availability of data-reduction pipelines. In the case of AF2+WYFFOS, the multi-object one-degree field-of-view fibre-fed spectrograph at the 4.2 m William Herschel Telescope (WHT), the full scientific exploitation of the data has often been slowed down because of the non-availability of a pipeline. A dedicated pipeline has been developed to overcome this. Running in IDL, it performs full reduction of AF2+WYFFOS data: fibre-to-fibre sensitivity corrections, fibre tracing, wavelength calibration, optimal extraction, sky subtraction.

  11. Modeling spall in HY100, HY130, and AF1410 steels

    NASA Astrophysics Data System (ADS)

    Garrett, R. K.; Rajendran, A. M.; Last, H. R.

    1996-05-01

    A comparison spall analysis between three matensitic steels: HY100, HY130, and AF1410 is presented Metallurgical observations on the fracture surfaces of uniaxial tensile specimens as well as the spalled target plates confirmed the nucleation, growth, and coalescence of microvoids in these steels. The threshold stress for void nucleation in these steels were determined from the spall analysis using the EPIC finite element code. According to the model, the spall nucleation occurred at higher stress levels in AF1410 compared to HY100 and HY130. A complete set of material model constants has been determined for these three steels.

  12. A CALM-derived nuclear export signal is essential for CALM-AF10–mediated leukemogenesis

    PubMed Central

    Conway, Amanda E.; Scotland, Paula B.; Lavau, Catherine P.

    2013-01-01

    The t(10;11) chromosomal translocation gives rise to the CALM-AF10 fusion gene and is found in patients with aggressive and difficult-to-treat hematopoietic malignancies. CALM-AF10–driven leukemias are characterized by HOXA gene up-regulation and a global reduction in H3K79 methylation. DOT1L, the H3K79 methyltransferase, interacts with the octapeptide/leucine zipper domain of AF10, and this region has been shown to be necessary and sufficient for CALM-AF10–mediated transformation. However, the precise role of CALM in leukemogenesis remains unclear. Here, we show that CALM contains a nuclear export signal (NES) that mediates cytoplasmic localization of CALM-AF10 and is necessary for CALM-AF10–dependent transformation. Fusions of the CALM NES (NESCALM-AF10) or NES motifs from heterologous proteins (ABL1, Rev, PKIA, APC) in-frame with AF10 are sufficient to immortalize murine hematopoietic progenitors in vitro. The CALM NES is essential for CALM-AF10–dependent Hoxa gene up-regulation and aberrant H3K79 methylation, possibly by mislocalization of DOT1L. Finally, we observed that CALM-AF10 leukemia cells are selectively sensitive to inhibition of nuclear export by Leptomycin B. These findings uncover a novel mechanism of leukemogenesis mediated by the nuclear export pathway and support further investigation of the utility of nuclear export inhibitors as therapeutic agents for patients with CALM-AF10 leukemias. PMID:23487024

  13. The splicing factor U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis

    SciTech Connect

    Kim, Jeonghee; Chung, In Kwon

    2014-01-17

    Highlights: •Identification of U2AF65 as a novel TRF1-interacting protein. •U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. •U2AF65 interferes with the interaction between TRF1 and Fbx4. •U2AF65 represents a new route for modulating TRF1 function at telomeres. -- Abstract: The human telomeric protein TRF1 is a component of the six-subunit protein complex shelterin, which provides telomere protection by organizing the telomere into a high-order structure. TRF1 functions as a negative regulator of telomere length by controlling the access of telomerase to telomeres. Thus, the cellular abundance of TRF1 at telomeres should be maintained and tightly regulated to ensure proper telomere function. Here, we identify U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor 65 (U2AF65), an essential pre-mRNA splicing factor, as a novel TRF1-interacting protein. U2AF65 interacts with TRF1 in vitro and in vivo and is capable of stabilizing TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. We also found that U2AF65 interferes with the interaction between TRF1 and Fbx4, an E3 ubiquitin ligase for TRF1. Depletion of endogenous U2AF65 expression by short interfering RNA (siRNA) reduced the stability of endogenous TRF1 whereas overexpression of U2AF65 significantly extended the half-life of TRF1. These findings demonstrate that U2AF65 plays a critical role in regulating the level of TRF1 through physical interaction and ubiquitin-mediated proteolysis. Hence, U2AF65 represents a new route for modulating TRF1 function at telomeres.

  14. The fatigue crack initiation at the interface between matrix and {delta}-ferrite in 304L stainless steel

    SciTech Connect

    Rho, B.S.; Hong, H.U.; Nam, S.W.

    1998-10-13

    It is well known that austenitic stainless steels have good mechanical properties and good corrosion resistance at high temperatures and are widely used in high temperature application. However, representative 304L stainless steel among austenitic stainless steels has the undesirable {delta}-ferrite in {gamma} matrix unavoidably because of the limitation of the manufacturing process. While large amounts of {delta}-ferrite in the austenitic stainless steels can give rise to a decrease in the hot workability, the absence of {delta}-ferrite in 304L stainless steel can be the cause of longitudinal facial crack and shortness of continuous cast slab. However, there are few reported papers related with the effect of {delta}-ferrite nucleating the initial crack at the interface between matrix and {delta}-ferrite on fatigue properties at high temperature. In the present work, a comparison of fatigue life with the amount of {delta}-ferrite was examined and to find out the mechanism of crack initiation caused by {delta}-ferrite, dislocation behavior near the interface between {delta}-ferrite and matrix during fatigue testing was analyzed. To analyze the dislocation character near the interface between the matrix and {delta}-ferrite during a low cycle fatigue test, trace analysis was applied. Using Burgers vector and dislocation line direction, calculated by trace analysis, it was possible to obtain some characteristic of dislocation behaviors near the interface.

  15. Wear-resistant and electromagnetic absorbing behaviors of oleic acid post-modified ferrite-filled epoxy resin composite coating

    NASA Astrophysics Data System (ADS)

    Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

    2015-03-01

    The post-modified Mn-Zn ferrite was prepared by grafting oleic acid on the surface of Mn-Zn ferrite to inhibit magnetic nanoparticle aggregation. Fourier Transform Infrared (FT-IR) spectroscopy was used to characterize the particle surfaces. The friction and electromagnetic absorbing properties of a thin coating fabricated by dispersing ferrite into epoxy resin (EP) were investigated. The roughness of the coating and water contact angle were measured using the VEECO and water contact angle meter. Friction tests were conducted using a stainless-steel bearing ball and a Rockwell diamond tip, respectively. The complex permittivity and complex permeability of the composite coating were studied in the low frequency (10 MHz-1.5 GHz). Surface modified ferrites are found to improve magnetic particles dispersion in EP resulting in significant compatibility between inorganic and organic materials. Results also indicate that modified ferrite/EP coatings have a lower roughness average value and higher water contact angle than original ferrite/EP coatings. The enhanced tribological properties of the modified ferrite/EP coatings can be seen from the increased coefficient value. The composite coatings with modified ferrite are observed to exhibit better reflection loss compared with the coatings with original ferrite.

  16. Effect of Ni-Zn ferrite on bandwidth and radiation efficiency of embedded antenna for mobile phone

    NASA Astrophysics Data System (ADS)

    Bae, S.; Hong, Y. K.; Lyle, A.

    2008-04-01

    Performance of inverted F meander antenna with a lossy ferrite film was investigated and compared to air-core antenna with the same design. We have fabricated ferrite film antenna using 3μm thick plated Ni0.21Zn0.45Fe2.34O4. Loss tanδμ of the plated ferrite was about 1.5 around 500MHz. It was found that bandwidth significantly increased by the use of lossy ferrite, while radiation efficiency (RE) decreased. However, the RE increases as the thickness of lossy ferrite film decreases below 10μm. The fractional bandwidth of ferrite film antenna was found to be 13.8%, which shows a 431% as compared to an air-core antenna. The center frequency (fc) for ferrite film antenna decreased from 584to534MHz of the air-core antenna. This implies 7.5% decrease in the fc, while the gain of the ferrite was not much lower than the air-core antenna. Lossy ferrite thin film has been found to be effective in broadening of bandwidth, while retaining an acceptable gain.

  17. Magneto acoustical emission in nanocrystalline Mn–Zn ferrites

    SciTech Connect

    Praveena, K.; Murthty, S.R.

    2013-11-15

    Graphical abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 °C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz–1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie temperature. It is found that the magneto-acoustic emission (MAE) activity along hysteresis loop is proportional to the hysteresis losses during the same loop. This law has been verified on series of polycrystalline ferrites and found that the law is valid whatever the composition, the grain size and temperature. It is also found that the domain wall creation/or annihilation processes are the origin of the MAE. - Highlights: • The AE been measured along the hysteresis loops from 80 K to Curie temperature. • The MAE activity along hysteresis loop is proportional to P{sub h} during the same loop. • It is found that the domain wall creation/or annihilation processes are the origin of the MAE. - Abstract: Mn{sub 0.4}Zn{sub 0.6}Fe{sub 2}O{sub 4} powders were prepared by microwave hydrothermal method. The powders were characterized by X-ray diffraction, transmission electron microscope. The powders were sintered at different temperatures 400, 500, 600, 700, 800 and 900 °C/30 min using microwave sintering method. The grain size was estimated by scanning electron microscope. The room temperature dielectric and magnetic properties were studied in the frequency range (100 kHz–1.8 GHz). The magnetization properties were measured upto 1.5 T. The acoustic emission has been measured along the hysteresis loops from 80 K to Curie

  18. Stress-relief cracking of a new ferritic steel

    NASA Astrophysics Data System (ADS)

    Nawrocki, Jesse Gerald

    The mechanism of stress-relief cracking in the coarse-grained heat-affected zone (CGHAZ) of low-alloy ferritic steels was studied through a tempering study, stress-relaxation testing, and detailed microstructural characterization. A new ferritic alloy steel, HCM2S, was used as the model system. Common 2.25Cr-1 Mo steel, which is susceptible to stress-relief cracking, was used for comparison to HCM2S. The CGHAZ was simulated using Gleeble techniques. A dense distribution of small tungsten-rich carbides within the prior austenite grains induced secondary hardening in the CGHAZ of HCM2S. The CGHAZ of 2.25Cr-1 Mo steel exhibited secondary hardening due to the intragranular precipitation of many Fe-rich M3C carbides. The hardness of HCM2S was more stable at longer times and high temperatures than 2.25Cr-1 Mo steel due to the intragranular precipitation of small W and V-rich carbides. The CGHAZs of HCM2S and 2.25Cr-1 Mo steel were susceptible to stress-relief cracking between 575 and 725°C. HCM2S exhibited C-curve behavior with respect to the time to failure as a function of post-weld heat treatment (PWHT) temperature. No segregation of tramp elements to prior austenite grain boundaries was detected in HCM2S. Both intergranular and intragranular carbide precipitation controlled the stress-relief cracking behavior. The amount of intergranular failure increased with test temperature due to the increasing amounts of Fe-rich M3C carbides at the prior austenite grain boundaries. These carbides acted as cavity nucleation sites. The cavities coalesced to form microcracks along prior austenite grain boundaries. Eventually, the remaining uncracked areas could not support the load and failed by ductile rupture. The balance of intergranular and intragranular carbide precipitation resulted in the C-curve behavior. The nose of the C-curve occurred at 675°C. The intragranular regions were strong because of a dense distribution of W/Fe-rich carbides, but the prior austenite grain

  19. Catalysts prepared from copper-nickel ferrites for the steam reforming of methanol

    NASA Astrophysics Data System (ADS)

    Huang, Yung-Han; Wang, Sea-Fue; Tsai, An-Pang; Kameoka, Satoshi

    2015-05-01

    In this study, Fe3O4-supported Cu and Ni catalysts are prepared through reduction of Cu-Ni (Ni1-xCuxFe2O4) ferrites. The Cu-Ni ferrites, synthesized using a solid-state reaction method, are reduced at temperatures from 240 °C to 500 °C in a H2 atmosphere. All ferrites are characterized with granular morphology and a smooth particle surface before reduction. For the CuFe2O4, Ni0.5Cu0.5Fe2O4 and NiFe2O4 ferrites reduced at 240, 300, and 400 °C, respectively, nanosized Cu and/or Ni particles (5-32 nm) and mesopores (5-30 nm) are distributed and adhered on the surfaces of Fe3O4 supports. After increasing the reduction temperature of NiFe2O4 ferrite to 500 °C, the Ni particles and mesopores disappear from the Fe3O4 surfaces, which is due to the formation of a Fe-Ni alloy covering on the Fe3O4 surfaces. The CuFe2O4 ferrite after H2 reduction at 240 °C exhibits the highest H2 production rate of 149 ml STP/min g-cat at 360 °C. The existence of Ni content in the Cu-Ni ferrites enhances the reverse water gas shift reaction, and raises the CO selectivity while reducing the CO2 selectivity. Formation of a Fe-Ni alloy exaggerates the trend and poisons the H2 production rate.

  20. 77 FR 14287 - Aspergillus flavus AF36; Amendment to an Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ...This regulation amends the existing temporary tolerance exemption for Aspergillus flavus AF36 by establishing a permanent exemption from the requirement of a tolerance for residues of the microbial pesticide, Aspergillus flavus AF36, in or on pistachio when applied as an antifungal agent and used in accordance with good agricultural practices. On behalf of the Arizona Cotton Research and......

  1. Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea.

    PubMed

    Dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

    2015-01-01

    Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. PMID:26634755

  2. Identification and Characterization of an Antifungal Protein, AfAFPR9, Produced by Marine-Derived Aspergillus fumigatus R9.

    PubMed

    Rao, Qi; Guo, Wenbin; Chen, Xinhua

    2015-05-01

    A fungal strain, R9, was isolated from the South Atlantic sediment sample and identified as Aspergillus fumigatus. An antifungal protein, AfAFPR9, was purified from the culture supernatant of Aspergillus fumigatus R9. AfAFPR9 was identified to be restrictocin, which is a member of the ribosome-inactivating proteins (RIPs), by MALDI-TOF-TOF-MS. AfAFPR9 displayed antifungal activity against plant pathogenic Fusarium oxysporum, Alternaria longipes, Colletotrichum gloeosporioides, Paecilomyces variotii, and Trichoderma viride at minimum inhibitory concentrations of 0.6, 0.6, 1.2, 1.2, and 2.4 μg/disc, respectively. Moreover, AfAFPR9 exhibited a certain extent of thermostability, and metal ion and denaturant tolerance. The iodoacetamide assay showed that the disulfide bridge in AfAFPR9 was indispensable for its antifungal action. The cDNA encoding for AfAFPR9 was cloned from A. fumigatus R9 by RTPCR and heterologously expressed in E. coli. The recombinant AfAFPR9 protein exhibited obvious antifungal activity against C. gloeosporioides, T. viride, and A. longipes. These results reveal the antifungal properties of a RIP member (AfAFPR9) from marine-derived Aspergillus fumigatus and indicated its potential application in controlling plant pathogenic fungi. PMID:25394604

  3. Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea

    PubMed Central

    dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues

    2015-01-01

    Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. PMID:26634755

  4. A method to decrease the harmonic distortion in Mn-Zn ferrite/PZT and Ni-Zn ferrite/PZT layered composite rings exhibiting high magnetoelectric effects

    NASA Astrophysics Data System (ADS)

    Loyau, V.; Morin, V.; Fortineau, J.; LoBue, M.; Mazaleyrat, F.

    2015-10-01

    We have investigated the magnetoelectric (ME) effect in layered composite rings subjected to circumferential AC magnetic fields and DC magnetic fields in radial, axial, or circumferential directions. Bilayer samples were obtained combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low magnetostriction saturation ( λs<10-6 ) and low magneto-crystalline anisotropy constants show high ME capabilities when associated with PZT in ring structures. In certain conditions, these ME effects are higher than those obtained with Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive and mechanical characterizations have given results that explain these high ME performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages responses with low linearity especially at high signal level. Based on the particular structure of the ME device, a method to decrease the nonlinear harmonic distortion of the ME voltages is proposed. Harmonic distortion analysis of ME voltages measured in different configurations allows us to explain the phenomenon.

  5. Oleate Coated Magnetic Cores Based on Magnetite, Zn Ferrite and Co Ferrite Nanoparticles—Preparation, Physical Characterization and Biological Impact on Helianthus Annuus Photosynthesis

    NASA Astrophysics Data System (ADS)

    Ursache-Oprisan, Manuela; Foca-nici, Ecaterina; Cirlescu, Aurelian; Caltun, Ovidiu; Creanga, Dorina

    2010-12-01

    Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic nanoparticle levels of 10-14-10-15/cm3) on sunflower seedlings was studied considering the changes in the photosynthesis pigment levels. Similar responses were obtained for magnetite and cobalt ferrite nanoparticle treatment consisting in the apparent inhibition of chlorophyll biosynthesis while for zinc ferrite nanoparticles some concentrations seemed to have stimulatory effects on the chlorophylls as well as on the carotene levels. But the chlorophyll ratio was diminished in the case of all three types of magnetic nanoparticles meaning their slight negative effect on the light harvesting complex II (LHC II) from the chloroplast membranes and consequently on the photosynthesis efficiency.

  6. The Coexistence of Two Different Pearlites, Lamellae of (Ferrite + M3C), and Lamellae of (Ferrite + M23C6) in a Mn-Al Steel

    NASA Astrophysics Data System (ADS)

    Cheng, Wei-Chun; Li, Yu-Cheng

    2012-06-01

    Two different pearlites after two separate eutectoid reactions were observed in an Fe-19.8 Mn-1.64 Al-1.03 C (wt pct) steel. The steel specimens were processed under solution heat treatment at 1373 K (1100 °C) and received isothermal holding at temperatures from 1073 K to 773 K (800 °C to 500 °C). The constituent phase of the steel is single austenite at temperatures between 1373 K and 1073 K (1100 °C and 800 °C). At temperatures below 1048 K (775 °C), M3C and M23C6 carbides coprecipitate at the austenitic grain boundaries. Two different pearlites appear in the austenite matrix simultaneously at temperatures below 923 K (650 °C). One is lamellae of ferrite and M3C carbide, and the other is lamellae of ferrite and M23C6 carbide. These two pearlites are product phases from two separate eutectoid reactions, i.e., austenite → ferrite + cementite and austenite → ferrite + M23C6. Therefore, the supersaturated austenite has decomposed into two different pearlites, separately.

  7. Oleate Coated Magnetic Cores Based on Magnetite, Zn Ferrite and Co Ferrite Nanoparticles - Preparation, Physical Characterization and Biological Impact on Helianthus Annuus Photosynthesis

    SciTech Connect

    Ursache-Oprisan, Manuela; Foca-nici, Ecaterina; Cirlescu, Aurelian; Caltun, Ovidiu; Creanga, Dorina

    2010-12-02

    Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic nanoparticle levels of 10{sup -14}-10{sup -15}/cm{sup 3}) on sunflower seedlings was studied considering the changes in the photosynthesis pigment levels. Similar responses were obtained for magnetite and cobalt ferrite nanoparticle treatment consisting in the apparent inhibition of chlorophyll biosynthesis while for zinc ferrite nanoparticles some concentrations seemed to have stimulatory effects on the chlorophylls as well as on the carotene levels. But the chlorophyll ratio was diminished in the case of all three types of magnetic nanoparticles meaning their slight negative effect on the light harvesting complex II (LHC II) from the chloroplast membranes and consequently on the photosynthesis efficiency.

  8. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  9. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  10. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  11. Fracture Mechanics Testing of Titanium 6AL-4V in AF-M315E

    NASA Technical Reports Server (NTRS)

    Sampson, J. W.; Martinez, J.; McLean, C.

    2016-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant on orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent processing flaws will not cause failure during the design life of the tank. Material property inputs for this analysis require testing to determine the stress intensity factor for environment-assisted cracking (KEAC) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched, or SE(B), specimens representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to AF-M315E at 50 C for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor for environment-assisted cracking of the Ti 6Al-4V forged tank material was found to be at least 22 ksivin and at least 31 ksivin for the weld material when exposed to AF-M315E monopropellant.

  12. K-theory of the chair tiling via AF-algebras

    NASA Astrophysics Data System (ADS)

    Julien, Antoine; Savinien, Jean

    2016-08-01

    We compute the K-theory groups of the groupoid C∗-algebra of the chair tiling, using a new method. We use exact sequences of Putnam to compute these groups from the K-theory groups of the AF-algebras of the substitution and the induced lower dimensional substitutions on edges and vertices.

  13. 28. Site Plan: AF Station P67, Fort Custer, Michigan, Plot ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Site Plan: AF Station P-67, Fort Custer, Michigan, Plot Plan (to accompany FY 1956 project planning report), USACOE, 22 July 1954. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  14. Acutangulosides A-F, monodesmosidic saponins from the bark of Barringtonia acutangula.

    PubMed

    Mills, Clive; Carroll, Anthony R; Quinn, Ronald J

    2005-03-01

    Nine triterpene saponins, acutangulosides A-F (2-7), and acutanguloside D-F methyl esters (5a-7a) and a single triterpene aglycone (1) were isolated from a water extract of the bark of Barringtonia acutangula. Their structures were assigned on the basis of spectroscopic data. PMID:15787427

  15. The role of nickel in radiation damage of ferritic alloys

    DOE PAGESBeta

    Osetskiy, Yury N.; Anento, Napoleon; Serra, Anna; Terentyev, Dmitry

    2014-11-26

    According to the modern theory damage evolution under neutron irradiation depends on the fraction of self interstitial atoms (SIAs) produced in the form of one-dimensionally (1-D) glissile clusters. These clusters, having a low interaction cross-section with other defects, sink mainly on grain boundaries and dislocations creating the so-called production bias. It is known empirically that addition of certain alloying elements affect many radiation effects, including swelling, however the mechanisms are unknown in many cases. In this paper we report the results of an extensive multi-technique atomistic level modeling of SIA clusters mobility in bcc Fe-Ni alloys with Ni content frommore » 0.8 to 10 at.%. We have found that Ni interacts strongly with periphery of clusters affecting their mobility. The total effect is defined by all Ni atoms interacting with the cluster at the same time and can be significant even in low-Ni alloys. Thus 1nm (37SIAs) cluster is practically immobile at T < 500K in the Fe-0.8at.% Ni alloy. Increasing cluster size and Ni content enhance cluster immobilization. Furthermore, this effect should have quite broad consequences in swelling rate, matrix damage accumulation, radiation induced hardening, etc. and the results obtained help in better understanding and prediction of radiation effects in Fe-Ni ferritic alloys.« less

  16. Magnetic heating of silica-coated manganese ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Iqbal, Yousaf; Bae, Hongsub; Rhee, Ilsu; Hong, Sungwook

    2016-07-01

    Manganese ferrite nanoparticles were synthesized using the reverse micelle method; these particles were then coated with silica. The silica-coated nanoparticles were spherical in shape, with an average diameter of 14 nm. The inverse spinel crystalline structure was observed through X-ray diffraction patterns. The coating status of silica on the surface of the nanoparticles was confirmed with a Fourier transform infrared spectrometer. The superparamagnetic properties were revealed by the zero coercive force in the hysteresis curve. Controllable heating at a fixed temperature of 42 °C was achieved by changing either the concentration of nanoparticles in the aqueous solution or the intensity of the alternating magnetic field. We found that at a fixed field strength of 5.5 kA/m, the 2.6 mg/ml sample showed a saturation temperature of 42 °C for magnetic hyperthermia. On the other hand, at a fixed concentration of 3.6 mg/ml, a field intensity of 4.57 kA/m satisfied the required temperature of 42 °C.

  17. Magnetic and electrical properties of In doped cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Nongjai, Razia; Khan, Shakeel; Asokan, K.; Ahmed, Hilal; Khan, Imran

    2012-10-01

    Nanoparticles of CoFe2O4 and CoIn0.15Fe1.85O4 ferrites were prepared by citrate gel route and characterized to understand their structural, electrical, and magnetic properties. X-ray diffraction and Raman spectroscopy were used to confirm the formation of single phase cubic spinel structure. The average grain sizes from the Scherrer formula were below 50 nm. Microstructural features were obtained by scanning electron microscope and compositional analysis by energy dispersive spectroscopy. The hysteresis curve shows enhancement in coercivity while reduction in saturation magnetization with the substitution of In3+ ions. Enhancement of coercivity is attributed to the transition from multidomain to single domain nature. Electrical properties, such as dc resistivity as a function of temperature and ac conductivity as a function of frequency and temperature were studied for both the samples. The activation energy derived from the Arrhenius equation was found to increase in the doped sample. The dielectric constant (ɛ') and dielectric loss (tan δ) are also studied as a function of frequency and temperature. The variation of dielectric properties ɛ', tan δ, and ac conductivity (σac) with frequency reveals that the dispersion is due to Maxwell-Wagner type of interfacial polarization in general and the hopping of charge between Fe2+ and Fe3+ as well as between Co2+ and Co3+ ions at B-sites. Magnetization and electrical property study showed its dominant dependence on the grain size.

  18. Calculation of exchange integrals and electronic structure for manganese ferrite

    NASA Astrophysics Data System (ADS)

    Zuo, Xu; Vittoria, Carmine

    2002-11-01

    The electrical and magnetic properties of manganese ferrite (MnFe2O4) are calculated with the density-functional theory (DFT) method for both normal and inverse spinel structures. The exchange functional is chosen to be a mixture of Becke exchange and Fock exchange with variable weight (w). The exchange integrals JAB (the exchange integral between the nearest-neighbor A and B sites) and JBB (the exchange integral between nearest-neighbor B sites) are calculated by substituting the total energies of different magnetic ground states into the Heisenberg model. The calculated value of JAB is in agreement with the experimental values measured by neutron diffraction and NMR. Also, the parameters U (Coulomb repulsion energy), Δ (charge-transfer energy), and EG (band gap) are extracted from the density of states (DOS) and plotted versus w. Our calculated band gap shows that MnFe2O4 is a complex insulator, in contrast to previous local spin-density approximation and generalized gradient approximation calculations, which showed it to be half metallic.

  19. Effect Of Neodymium Substitution In Structural Characteristics Of Magnesium Ferrite

    SciTech Connect

    Thankachan, Smitha; Binu, P. J.; Xavier, Sheena; Mohammed, E. M.

    2011-10-20

    The effect of Nd{sup 3+} substitution on the structural properties of Magnesium ferrite was studied in the series MgNd{sub x}Fe{sub 2-x}O{sub 4}, where x = 0 to 0.3 in steps of 0.05. The series was prepared by sol-gel technique which is one of the novel technique to prepare nanosized samples. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. XRD analysis reveals the prepared samples are single phasic till x = 0.2. From x0 = .25, a secondary phase of iron neodymium oxide appears along with the spinel phase. Particle size calculation shows the prepared samples are in the 9nm to 11 nm regime. Lattice parameter was found to increase with concentration of Nd. XRD and FTIR analysis confirmed spinel structure of the prepared samples. XRF result shows the expected composition of prepared samples. The frequency dependence of the dielectric constant in the range 100 Hz--120MHz was also studied

  20. Investigations of low-temperature neutron embrittlement of ferritic steels

    SciTech Connect

    Farrell, K.; Mahmood, S.T.; Stoller, R.E.; Mansur, L.K.

    1992-12-31

    Investigations were made into reasons for accelerated embrittlement of surveillance specimens of ferritic steels irradiated at 50C at the High Flux Isotope Reactor (HFIR) pressure vessel. Major suspects for the precocious embrittlement were a highly thermalized neutron spectrum,a low displacement rate, and the impurities boron and copper. None of these were found guilty. A dosimetry measurement shows that the spectrum at a major surveillance site is not thermalized. A new model of matrix hardening due to point defect clusters indicates little effect of displacement rate at low irradiation temperature. Boron levels are measured at 1 wt ppM or less, inadequate for embrittlement. Copper at 0.3 wt % and nickel at 0.7 wt % are shown to promote radiation strengthening in iron binary alloys irradiated at 50 to 60C, but no dependence on copper and nickel was found in steels with 0.05 to 0.22% Cu and 0.07 to 3.3% Ni. It is argued that copper impurity is not responsible for the accelerated embrittlement of the HFIR surveillance specimens. The dosimetry experiment has revealed the possibility that the fast fluence for the surveillance specimens may be underestimated because the stainless steel monitors in the surveillance packages do not record an unexpected component of neutrons in the spectrum at energies just below their measurement thresholds of 2 to 3 MeV.

  1. Long-term high temperature oxidation behavior of ODS ferritics

    NASA Astrophysics Data System (ADS)

    Pint, B. A.; Wright, I. G.

    2002-12-01

    Four oxide dispersion strengthened Fe-(13-14 at.%) Cr ferritic compositions were exposed in air and air with 10 vol.% water vapor for up to 10 000 h at 700-1100 °C. At 700-800 °C in air, the reaction rates were very low for all of the alloys compared to stainless steels. At 900 °C, a dispersion of Y 2O 3, compared to Al 2O 3, showed a distinct benefit in improving the oxidation resistance, due to a reactive element effect. However, failure occurred after 7000 h at 900 °C when only 13% Cr was present. The absence of Ti and W in one alloy appeared to result in a thinner reaction product after oxidation at 800 °C. One composition was exposed in 10 vol.% water vapor at 800 and 900 °C and in air at 1000 and 1100 °C. Under both of these conditions, there was a significant increase in the rates of oxidation. With the relatively low Cr contents in these alloys, their corrosion-limited operating temperature in air is near 900 °C.

  2. Ferroelectric and photocatalytic behavior of bismuth ferrite nano wire

    NASA Astrophysics Data System (ADS)

    William, R. V.; Marikani, A.; Madhavan, D.

    2016-05-01

    Multiferroic bismuth ferrite nanowires are prepared through polyol method with an average diameter of 35 nm with a narrow size distribution. The band gap was determined to be 2.10 eV, indicating their potential application as visible-light-response photo catalyst. The magnificent photocatalytic behaviors of BiFeO3 nanowires are understood from the methyl violet degradation under visible light irradiation. Moreover, the nano-wire takes only a lesser time for the diffusion of electron-hole pair from the surface of the sample. Further the BiFeO3 nano-wire was characterized using XRD, SEM, and U-V. The ferroelectric studies of BiFeO3 nano-wire show a frequency dependent property and maximum coercivity of 2.7 V/cm were achieved with a remanent polarization at 0.5 µC/cm2 at the frequency 4 kHz. The coercivity of BiFeO3 nano wire changes with variation of frequency from 1 kHz to 4 kHz.

  3. Magnetic liposomes based on nickel ferrite nanoparticles for biomedical applications.

    PubMed

    Rodrigues, Ana Rita O; Gomes, I T; Almeida, Bernardo G; Araújo, J P; Castanheira, Elisabete M S; Coutinho, Paulo J G

    2015-07-21

    Nickel ferrite nanoparticles with superparamagnetic behavior at room temperature were synthesized using a coprecipitation method. These magnetic nanoparticles were either covered with a lipid bilayer, forming dry magnetic liposomes (DMLs), or entrapped in liposomes, originating aqueous magnetoliposomes (AMLs). A new and promising method for the synthesis of DMLs is described. The presence of the lipid bilayer in DMLs was confirmed by FRET (Förster Resonance Energy Transfer) measurements between the fluorescent-labeled lipids NBD-C12-HPC (NBD acting as a donor) included in the second lipid layer and rhodamine B-DOPE (acceptor) in the first lipid layer. An average donor-acceptor distance of 3 nm was estimated. Assays of the non-specific interactions of magnetoliposomes with biological membranes (modeled using giant unilamellar vesicles, GUVs) were performed. Membrane fusion between both aqueous and dry magnetoliposomes and GUVs was confirmed by FRET, which is an important result regarding applications of these systems both as hyperthermia agents and antitumor drug nanocarriers. PMID:26095537

  4. Synthesis and magnetic properties of tin spinel ferrites doped manganese

    NASA Astrophysics Data System (ADS)

    El Moussaoui, H.; Mahfoud, T.; Habouti, S.; El Maalam, K.; Ben Ali, M.; Hamedoun, M.; Mounkachi, O.; Masrour, R.; Hlil, E. K.; Benyoussef, A.

    2016-05-01

    In this work we report the synthesis, the microstructural characterization and the magnetic properties of tin spinel ferrites doped manganese (Sn1-xMnxFe2O4 with x=0.25, 0.5, 0.75, and 1) nanoparticles prepared by co-precipitation method. The effect of annealing temperature on the structure, morphology and magnetic properties of Sn0.5Mn0.5Fe2O4 has been investigated. The synthesized nanoparticle sizes have been controlled between 4 and 9 nm, with uniform spherical morphology as confirmed by transmission electron microscopy (TEM). All the samples prepared possess single domain magnetic. The nanoparticles of Sn0.5Mn0.5Fe2O4 with 4 nm in diameter have a blocking temperature close to 100 K. In addition, the cation distribution obtained from the X-ray diffraction of this sample was confirmed by magnetic measurement. For the Sn1-xMnxFe2O4; (0≤x≤1) samples, the magnetization and coercive fields increase when the augmentation of Mn content increases. For x=0.5, such parameters decrease when the calcination temperature increases.

  5. Ferroelectric and dielectric properties of ferrite-ferroelectric ceramic composites

    SciTech Connect

    Elena Ciomaga, Cristina; Maria Neagu, Alexandra; Valentin Pop, Mihai; Mitoseriu, Liliana; Airimioaei, Mirela; Tascu, Sorin; Schileo, Giorgio; Galassi, Carmen

    2013-02-21

    Particulate composites of ferrite and ferroelectric phases with xNiFe{sub 2}O{sub 4} (NF) and (1 - x)Pb{sub 0.988}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.976}Nb{sub 0.024}O{sub 3} (where x = 2, 10, 20, 30, 50, 70, and 100 wt. %) were prepared in situ by sol-gel method. The presence of a diphase composition was confirmed by X-ray diffraction while the microstructure of the composites was studied by scanning electron microscopy revealing a good mixing of the two phases and a good densification of the bulk ceramics. The dielectric permittivity shows usual dielectric dispersion behavior with increasing frequency due to Maxwell-Wagner interfacial polarization. AC conductivity measurements made in frequency range 1 Hz-1 MHz suggest that the conduction process is due to mixed polaron hopping. The effect of NF phase concentration on the P-E and M-H hysteresis behavior and dielectric properties of the composites was investigated. At low NF concentration a sharp ferro-paraelectric transition peak can be observed at around 360 Degree-Sign C while for higher NF concentrations a trend to a diffuse phase transition occurs. All the composite samples exhibit typical ferromagnetic hysteresis loops, indicating the presence of ordered magnetic structure.

  6. UNDERSTANDING DAMAGE MECHANISMS IN FERRITIC/MARTENSITIC STEELS

    SciTech Connect

    Swindeman, R.W.; Maziasz, P.J.; Swindeman, M.J.

    2003-04-22

    Advanced ferritic/martensitic steels are being used extensively in fossil energy applications. New steels such as 2 1/4Cr-W-V (T23, T24), 3Cr-W-V, 9Cr-Mo-V (T91), 7Cr-W-V, 9Cr-W-V (T92 and T911), and 12Cr-W-V (T122, SAVE 12, and NF12) are examples of tubing being used in boilers and heat recovery steam generators (1). Other products for these new steels include piping, plates, and forgings. There is concern about the high-temperature performance of the advanced steels for several reasons. First, they exhibit a higher sensitivity to temperature than the 300 series stainless steels that they often replace. Second, they tend to be metallurgically unstable and undergo significant degradation at service temperatures in the creep range. Third, the experience base is limited in regard to duration. Fourth, they will be used for thick-section, high-pressure components that require high levels of integrity. To better understand the potential limitations of these steels, damage models are being developed that consider metallurgical factors as well as mechanical performance factors. Grade 91 steel was chosen as representative of these steels for evaluation of cumulative damage models since laboratory and service exposures of grade 91 exceed 100,000 hours.

  7. New ferritic steels increase the thermal efficiency of steam turbines

    SciTech Connect

    Mayer, K.H.; Bakker, W.T.

    1996-12-31

    The further development of ferritic high-temperature-resistant 9--11%Cr steels has paved the way for fossil-fired power stations to be operated at turbine steam inlet temperatures of up to around 600 C and high supercritical steam pressures with a distinct improvement in thermal efficiency, a significant contribution towards reducing the environmental impact of SO{sub 2}, NO{sub x} and CO{sub 2} emissions and to a more economical utilization of fossil fuels. Advances in the development of these steels are primarily attributable to joint research projects undertaken by the manufacturers and operators of power stations in Japan (EPDC), in the USA (EPRI) and in Europe (COST 501). The report gives details on the results achieved under EPRI Research Project RP 140 3-15/23 on the creep behavior of modified 9%CrMo cast steel used in the manufacture of steam turbines for coal-fired power plants. The modified 9%CrMo cast steel also offers great benefits as regards improving the useful life and thermal efficiency of existing power plants.

  8. Spin-phonon coupling in scandium doped gallium ferrite

    SciTech Connect

    Chakraborty, Keka R. E-mail: smyusuf@barc.gov.in; Mukadam, M. D.; Basu, S.; Yusuf, S. M. E-mail: smyusuf@barc.gov.in; Paul, Barnita; Roy, Anushree; Grover, Vinita; Tyagi, A. K.

    2015-03-28

    We embarked on a study of Scandium (Sc) doped (onto Ga site) gallium ferrite (GaFeO{sub 3}) and found remarkable magnetic properties. In both doped as well as parent compounds, there were three types of Fe{sup 3+} ions (depending on the symmetry) with the structure conforming to space group Pna2{sub 1} (Sp. Grp. No. 33) below room temperature down to 5 K. We also found that all Fe{sup 3+} ions occupy octahedral sites, and carry high spin moment. For the higher Sc substituted sample (Ga{sub 1−x}Sc{sub x}FeO{sub 3}: x = 0.3), a canted magnetic ordered state is found. Spin-phonon coupling below Néel temperature was observed in doped compounds. Our results indicated that Sc doping in octahedral site modifies spin-phonon interactions of the parent compound. The spin-phonon coupling strength was estimated for the first time in these Sc substituted compounds.

  9. Exchange spring like magnetic behavior in cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Chithra, M.; Anumol, C. N.; Sahu, Baidyanath; Sahoo, Subasa C.

    2016-03-01

    Cobalt ferrite nanoparticles were prepared by sol-gel technique and were annealed at 900 °C in air for 2 h. Structural properties were studied by X-ray diffraction, Raman spectroscopy and Fourier transformed infrared spectroscopy. Scanning electron microscopy and transmission electron microscopy studies show presence of mostly two different sizes of grains in these samples. Magnetization value of 58.36 emu/g was observed at 300 K for the as prepared sample and an enhanced magnetization close to the bulk value of 80.59 emu/g was observed for the annealed sample. At 10 K a two stepped hysteresis loop showing exchange spring magnetic behavior was observed accompanied by very high values of coercivity and remanence. Two clear peaks were observed in the derivative of demagnetization curve in the as prepared sample where as two partially overlapped peaks were observed in the annealed sample. The observed magnetic properties can be understood on the basis of the grain size and their distribution leading to the different types of intergranular interactions in these nanoparticles.

  10. Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Salunkhe, A. B.; Khot, V. M.; Thorat, N. D.; Phadatare, M. R.; Sathish, C. I.; Dhawale, D. S.; Pawar, S. H.

    2013-01-01

    In the present work, cobalt ferrite nanoparticles (CoFe2O4 NPs) have been synthesized by combustion method. The surface of the CoFe2O4 NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe2O4 NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe2O4 NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe2O4 NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe2O4 NPs up to 1.8 mg mL-1 when tested with mouse fibroblast L929 cell line.

  11. Tritium retention in reduced-activation ferritic/martensitic steels

    SciTech Connect

    Hatano, Y.; Abe, S.; Matsuyama, M.; Alimov, V.K.; Spitsyn, A.V.; Bobyr, N.P.; Cherkez, D.I.; Khripunov, B.I.; Golubeva, A.V.; Ogorodnikova, O.V.; Klimov, N.S.; Chernov, V.M.; Oyaidzu, M.; Yamanishi, T.

    2015-03-15

    Reduced-activation ferritic/martensitic (RAFM) steels are structural material candidates for breeding blankets of future fusion reactors. Therefore, tritium (T) retention in RAFM steels is an important problem in assessing the T inventory of blankets. In this study, specimens of RAFM steels were subjected to irradiation of 20 MeV W ions to 0.54 displacements per atom (dpa), exposure to high flux D plasmas at 400 and 600 K and that to pulsed heat loads. The specimens thus prepared were exposed to DT gas at 473 K. Despite severe modification in the surface morphology, heat loads had negligible effects on T retention. Significant increase in T retention at the surface and/or subsurface was observed after D plasma exposure. However, T trapped at the surface/subsurface layer was easily removed by maintaining the specimens in the air at about 300 K. Displacement damage led to increase in T retention in the bulk due to the trapping effects of defects, and T trapped was stable at 300 K. It was therefore concluded that displacement damages had the largest influence on T retention under the present conditions.

  12. Vacancy-controlled ultrastable nanoclusters in nanostructured ferritic alloys

    DOE PAGESBeta

    Zhang, Z. W.; Yao, L.; Wang, X. -L.; Miller, M. K.

    2015-05-29

    A new class of advanced structural materials, based on the Fe-O-vacancy system, has exceptional resistance to high-temperature creep and excellent tolerance to extremely high-dose radiation. Although these remarkable improvements in properties compared to steels are known to be associated with the Y-Ti-O-enriched nanoclusters, the roles of vacancies in facilitating the nucleation of nanoclusters are a long-standing puzzle, due to the experimental difficulties in characterizing vacancies, particularly in-situ while the nanoclusters are forming. We report an experiment study that provides the compelling evidence for the presence of significant concentrations of vacancies in Y-Ti-O-enriched nanoclusters in a nanostructured ferritic alloy using amore » combination of state-of-the-art atom-probe tomography and in situ small angle neutron scattering. The nucleation of nanoclusters starts from the O-enriched solute clustering with vacancy mediation. The nanoclusters grow with an extremely low growth rate through attraction of vacancies and O:vacancy pairs, leading to the unusual stability of the nanoclusters.« less

  13. The role of nickel in radiation damage of ferritic alloys

    SciTech Connect

    Osetskiy, Yury N.; Anento, Napoleon; Serra, Anna; Terentyev, Dmitry

    2014-11-26

    According to the modern theory damage evolution under neutron irradiation depends on the fraction of self interstitial atoms (SIAs) produced in the form of one-dimensionally (1-D) glissile clusters. These clusters, having a low interaction cross-section with other defects, sink mainly on grain boundaries and dislocations creating the so-called production bias. It is known empirically that addition of certain alloying elements affect many radiation effects, including swelling, however the mechanisms are unknown in many cases. In this paper we report the results of an extensive multi-technique atomistic level modeling of SIA clusters mobility in bcc Fe-Ni alloys with Ni content from 0.8 to 10 at.%. We have found that Ni interacts strongly with periphery of clusters affecting their mobility. The total effect is defined by all Ni atoms interacting with the cluster at the same time and can be significant even in low-Ni alloys. Thus 1nm (37SIAs) cluster is practically immobile at T < 500K in the Fe-0.8at.% Ni alloy. Increasing cluster size and Ni content enhance cluster immobilization. Furthermore, this effect should have quite broad consequences in swelling rate, matrix damage accumulation, radiation induced hardening, etc. and the results obtained help in better understanding and prediction of radiation effects in Fe-Ni ferritic alloys.

  14. Dielectric behaviour of Zn substituted Cu nano-ferrites

    NASA Astrophysics Data System (ADS)

    Parashar, Jyoti; Saxena, V. K.; Jyoti; Bhatnagar, Deepak; Sharma, K. B.

    2015-11-01

    Herein, the dielectric properties such as permittivity (real part ε‧ and imaginary part ε‧‧) and dielectric loss tangent (tan δ) are reported for Zn substituted Cu ferrites (Cu1-xZnxFe2O4; 0≤x≤1) composite using the sol-gel auto-combustion method. The variations of real and imaginary part of dielectric constant, tan δ and AC conductivity (σac) are studied at room temperature in the frequency range of 100 Hz-120 MHz. The real part of dielectric constant decrease with increasing frequency and the imaginary part (ε‧‧) varies with frequency showing the characteristic peak for each sample. The relation of tan δ with frequency shows relaxation spectra. Further, the σac tended to increase with increase in frequency. The variation in dielectric constant may be explained on the basis of space charge polarization, according to Maxwell and Wagner two-layer model. The dielectric constant and tan δ as a function of temperature are also studied with different temperatures ranging from 323 K to 583 K.

  15. Microwave Dielectric and Magnetic Properties of Co-Zn Ferrites

    NASA Astrophysics Data System (ADS)

    Lamani, A. R.; Jayanna, H. S.; Naveen, C. S.; Rajeeva, M. P.; Prasanna, G. D.

    2015-02-01

    The dielectric permittivity, loss tangent, in the frequency range 1MHz to 1.8 GHz and hysteresis loop parameters at room temperature were studied on a series of Zn substituted cobalt ferrites with general formula Co1-xZnx Fe2O4 where (x=0.0, 0.2, 0.4, 0.6, 1.0.). The experimental results indicate that the Zn substitution affects all these parameters. The observed dispersion in dielectric permittivity with frequency is in accordance with Maxwell-Wagner model. The high temperature sintering is used to synthesize these materials via solid state reaction route and these samples were characterized by X-ray diffractometer (XRD), vibrating sample magnetometer (VSM). The saturation magnetizations (MS) Hc and Mr of the Particles were measured at room temperature. Here for the smaller dopent concentration Ms increases with increasing in the Zn content this can explained on the basis of increased number of magnetic ions in the spinel lattice, at some point Ms decrease because of the difference between the magnetic moment of Fe2+ and Zn2+, the magnetic moment of the A sub lattice will increases and the moment of the B sub lattice will decrease. The variation of crystalline shape ellipsoid is correlated with variation of dielectric constant.

  16. Moessbauer spectra of ferrite catalysts used in oxidative dehydrogenation

    NASA Technical Reports Server (NTRS)

    Cares, W. R.; Hightower, J. W.

    1971-01-01

    Room temperature Mossbauer spectroscopy was used to examine bulk changes which occur in low surface area CoFe2O4 and CuFe2O4 catalysts as a result of contact with various mixtures of trans-2-butene and O2 during oxidative dehydrogenation reactions at about 420 C. So long as there was at least some O2 in the gas phase, the CoFe2O4 spectrum was essentially unchanged. However, the spectrum changed from a random spinel in the oxidized state to an inverse spinel as it was reduced by oxide ion removal. The steady state catalyst lies very near the fully oxidized state. More dramatic solid state changes occurred as the CuFe2O4 underwent reduction. Under severe reduction, the ferrite was transformed into Cu and Fe3O4, but it could be reversibly recovered by oxidation. An intense doublet located near zero velocity persisted in all spectra of CuFe2O4 regardless of the state of reduction.

  17. Magnetoelectric Effect in Ceramics Based on Bismuth Ferrite

    NASA Astrophysics Data System (ADS)

    Jartych, Elżbieta; Pikula, Tomasz; Kowal, Karol; Dzik, Jolanta; Guzdek, Piotr; Czekaj, Dionizy

    2016-04-01

    Solid-state sintering method was used to prepare ceramic materials based on bismuth ferrite, i.e., (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions and the Aurivillius Bi5Ti3FeO15 compound. The structure of the materials was examined using X-ray diffraction, and the Rietveld method was applied to phase analysis and structure refinement. Magnetoelectric coupling was registered in all the materials using dynamic lock-in technique. The highest value of magnetoelectric coupling coefficient α ME was obtained for the Bi5Ti3FeO15 compound ( α ME ~ 10 mVcm-1 Oe-1). In the case of (BiFeO3)1 - x -(BaTiO3) x and Bi1 - x Nd x FeO3 solid solutions, the maximum α ME is of the order of 1 and 2.7 mVcm-1 Oe-1, respectively. The magnitude of magnetoelectric coupling is accompanied with structural transformation in the studied solid solutions. The relatively high magnetoelectric effect in the Aurivillius Bi5Ti3FeO15 compound is surprising, especially since the material is paramagnetic at room temperature. When the materials were subjected to a preliminary electrical poling, the magnitude of the magnetoelectric coupling increased 2-3 times.

  18. Lanthana-bearing nanostructured ferritic steels via spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Pasebani, Somayeh; Charit, Indrajit; Wu, Yaqiao; Burns, Jatuporn; Allahar, Kerry N.; Butt, Darryl P.; Cole, James I.; Alsagabi, Sultan F.

    2016-03-01

    A lanthana-containing nanostructured ferritic steel (NFS) was processed via mechanical alloying (MA) of Fe-14Cr-1Ti-0.3Mo-0.5La2O3 (wt.%) and consolidated via spark plasma sintering (SPS). In order to study the consolidation behavior via SPS, sintering temperature and dwell time were correlated with microstructure, density, microhardness and shear yield strength of the sintered specimens. A bimodal grain size distribution including both micron-sized and nano-sized grains was observed in the microstructure of specimens sintered at 850, 950 and1050 °C for 45 min. Significant densification occurred at temperatures greater than 950 °C with a relative density higher than 98%. A variety of nanoparticles, some enriched in Fe and Cr oxides and copious nanoparticles smaller than 10 nm with faceted morphology and enriched in La and Ti oxides were observed. After SPS at 950 °C, the number density of Cr-Ti-La-O-enriched nanoclusters with an average radius of 1.5 nm was estimated to be 1.2 × 1024 m-3. The La + Ti:O ratio was close to 1 after SPS at 950 and 1050 °C; however, the number density of nanoclusters decreased at 1050 °C. With SPS above 950 °C, the density improved but the microhardness and shear yield strength decreased due to partial coarsening of the grains and nanoparticles.

  19. Vacancy-controlled ultrastable nanoclusters in nanostructured ferritic alloys

    SciTech Connect

    Zhang, Z. W.; Yao, L.; Wang, X. -L.; Miller, M. K.

    2015-05-29

    A new class of advanced structural materials, based on the Fe-O-vacancy system, has exceptional resistance to high-temperature creep and excellent tolerance to extremely high-dose radiation. Although these remarkable improvements in properties compared to steels are known to be associated with the Y-Ti-O-enriched nanoclusters, the roles of vacancies in facilitating the nucleation of nanoclusters are a long-standing puzzle, due to the experimental difficulties in characterizing vacancies, particularly in-situ while the nanoclusters are forming. We report an experiment study that provides the compelling evidence for the presence of significant concentrations of vacancies in Y-Ti-O-enriched nanoclusters in a nanostructured ferritic alloy using a combination of state-of-the-art atom-probe tomography and in situ small angle neutron scattering. The nucleation of nanoclusters starts from the O-enriched solute clustering with vacancy mediation. The nanoclusters grow with an extremely low growth rate through attraction of vacancies and O:vacancy pairs, leading to the unusual stability of the nanoclusters.

  20. Harmonic Ratcheting for Ferrite Tuned RF Acceleration of Charged Particles

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Brennan, Mike

    2013-04-01

    One of the most persistent difficulties in the design of RF cavities for acceleration of charged particles is the rapid and efficient acceleration of particles over a large range of frequencies. From medical synchrotrons to accelerator driven systems, there is a strong need for fast acceleration of protons and light ions over hundreds of MeV. Conventionally, this is a costly undertaking, requiring specially designed ferrite loaded cavities to be tuned over a large range of frequencies. Ferromagnetic materials allow for the precise adjustment of cavity resonant frequency, but rapid changes in the frequency as well as operation outside material specific frequency ranges result in significant Q-loss to the cavity. This leads to a considerable increase in power required and is thus undesirable for regular operation. We introduce an acceleration scheme known as harmonic ratcheting which can be used to reduce the cavity frequency range needed for accelerating an ion beam in a synchrotron. In particular, this scheme addresses the need for high rep. rate machines for applications such as radiation therapy in which low beam intensity is needed. We demonstrate with simulations the type of ramps achievable using this technique and consider its advantages over h=1 acceleration schemes.