Moessbauer spectroscopy and X-ray diffraction studies of Fe-Ni order-disorder processes in a 35% Ni meteorite (Santa Catharina)

International Nuclear Information System (INIS)

Scorzelli, R.B.; Danon, J.

1985-01-01

The composition and structure of iron-nickel alloys in the Santa Catharina iron meteorite were investigated by metallographic techniques, electron microprobe analysis, Moessbauer spectroscopy and X-ray diffraction. The occurence of an ordered Fe-Ni phase with non-cubic symmetry is demonstrated. This phase is present in large proportions in the Santa Catharina meteorite, and has been identified by its asymmetric Moessbauer spectrum, arising from the presence of a quadrupolar splitting superposed on the magnetic hyperfine splitting. The other major Fe-Ni phase in Santa Catharina gives rise to a single line Moessbauer spectrum with no hyperfine components. X-ray diffraction confirms the presence of the Fe-Ni Llo superstructure in this meteorite. Lattice parameter variations with temperature were found to be identical for the meteorite and for electron irradiated Fe-Ni alloys of the sample composition. Detailed Moessbauer spectroscopy studies from room temperature to liquid helium, and in the presence of external magnetic field show the presence of a smaller amount of another ferromagnetic Fe-Ni phase, probably with disordered structure. The destruction of the superstructure in the Santa Catharina meteorite was investigated after heating the samples. Partial ordering seems to coexist with the disordered phase at intermediate annealing temperatures. At higher temperatures the samples are homogeneous and similar to laboratory produced Fe-Ni alloys with 35% Ni. Order-disorder transformations produced by shock waves and by mechanical treatment are also described. (orig.)

Prevalencia de infeccion por HTLV-I/II en donantes de sangre de la provincia de Santa Fe, Argentina Prevalence of HTLV-I/II infection among blood donors in Santa Fe Province, Argentina

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Roque O. Brun

2004-04-01

Full Text Available Subsecuentemente a que en 1997 el Programa Nacional de SIDA implementó un Programa deVigilancia Epidemiológica a escala nacional, se comenzaron a detectar anticuerpos anti-HTLV-I/II en donantes de sangre de la Provincia de Santa Fe. En base a ese hallazgo inicial, se consideró pertinente estimar la seroprevalencia de HTLV-I/II en donantes santafecinos en el curso de los 4 años siguientes. Así, desde 1997 hasta 2002, se estudiaron 9425 muestras provenientes de 17 de los 19 departamentos de la Provincia. Del total de muestras, 38 resultaron reactivas por técnicas de tamizaje, y de ellas 18 fueron confirmadas por western blot (WB. De esas muestras, 10 fueron HTLV-I/II seropositivas con una prevalencia final de 0.1% (10/9425, en tanto que 7 resultaron indeterminadas y 1 negativa. De las seropositivas, 2 (0.02 % eran HTLV, 3 (0.03 % HTLV-I, y 5 (0.05 % HTLV-II. Cabe destacar que por primera vez se constató la presencia de infección por HTLV-I/II en donantes de sangre de Santa Fe, y con una prevalencia mayor a las referidas para donantes de sangre de áreas no endémicas de Argentina. Estos datos fundamentan la necesidad de un screening sistemático para la infección por HTLV-I/II mediante normas regulatorias en bancos de sangre de esta provincia.Subsequent to the National Epidemiologic Surveillance Program developed in 1997 by the National AIDS Program, anti-HTLV-I/II antibodies among blood donors in Santa Fe Province started to be detected. On the basis of this initial finding, it was regarded of interest to evaluate the true HTLV-I/II seroprevalence in this population during a four-year survey. Thus, from 1997 up to 2002, 9425 samples were studied from 17 out of the 19 provincial departments. Out of the total sampling, 38 proved reactive by agglutination techniques, 18 of which were confirmed by western blot (WB. Out of the latter, 10 were HTLV-I/II seropositive with a final prevalence of 0.1% (10/9425, whereas 7 were indeterminate and 1

Remediation of acid mine drainage from the Santa Fe tin mine, Bolivia

Science.gov (United States)

Calvo, Daniel; Zamora Echenique, Gerardo; Alfonso, Pura; Casado, Jordi; Trujillo, Elvys; Jiménez-Franco, Abigail; Garcia-Valles, Maite

2015-04-01

The Santa Fe mine, department of Oruro, is located in the Andean Tin belt, is exploited for tin, zinc, lead and silver. This in an underground mine mined up to the -108 level. Today it is only mined up to the -50 level. Under this level the table water covers the mine. Water reaches the surface with a very acidic composition, with a high content in potentially toxic elements. This water drains directly to the Santa Fe River and contribute to the pollution present in this river that directly affect to the aquatic communities. In addition, population of this area have problems in the supply of drinking water, so remediation by obtaining cleaning water is a priority for this area. This study presents a neutralization-precipitation treatment with lime to the acid water inside the mine. The ore mineralogy of the Santa Fe mined deposit consists mainly in cassiterite, pyrite, sphalerite, galena, arsenopyrite argentite and sulphosalts. The host mineral is mainly quartz, with a minor content in feldspars and tourmaline. Alteration minerals as alunite, goethite and pumbojarosite are abundant and indicate the occurrence of reactions that lead to the formation of acid mine drainage. The mean pH of water drained from the Santa Fe mine is 2.2 and chemical analyses show high contents in potentially toxic elements: 27-295 ppm Zn, 0.05-0.2 ppm Pb, 0.06-0.09 ppm Cd, 04-0.12 ppm Cu, 113-165 ppm Fe, 4 ppm Mn and 564-664 ppm S. As and Sb were under 0.5 ppm. A settler tank inside the mine was designed by means of seal a selected gallery to clean the mine water. The function of this gallery is to sediment the sludge resulting from the neutralization - precipitation treatment process to obtain a clear water overflow continuously to the outside. The neutralization tests indicate that 0.65g/L of lime and 2ml of flocculant should be added to neutralize water up to pH 6-7. A flow rate of 80 L /s was considered. After a geotechnical study, a chamber located in the mine was selected to locate

Historia de uso del suelo y contenido de micronutrientes en argiudoles del centro de la provincia de Santa Fe (Argentina History of soil use and micronutrient content in argiudolls of the center of the Santa Fe province (Argentina

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María Celeste Miretti

2012-07-01

Full Text Available Las investigaciones realizadas en la zona Central de la provincia de Santa Fe en relación con la concentración y biodisponibilidad de micronutrientes en los suelos son muy limitadas, por lo que los objetivos del presente trabajo fueron: a determinar si se produjo una disminución en los contenidos de micronutrientes en Argiudoles del centro de la provincia de Santa Fe como consecuencia del uso a que fueron destinados y b correlacionar la biodisponibilidad con propiedades del suelo que se conoce que fueron afectadas por la intensificación de los sistemas productivos (MO, pH. Se trabajó en el departamento Las Colonias (Santa Fe, en suelos Argiudoles. Se colectaron muestras compuestas de 20 lotes en condiciones prístinas (CP, 22 lotes con uso ganadero dedicados a la producción láctea (G, 24 lotes con historia agrícola-ganadera (AG y 20 lotes con prolongada historia agrícola (A, que se utilizaron para determinar: pH, carbono orgánico oxidable (CO, boro (B, cobre (Cu, hierro (Fe, manganeso (Mn y cinc (Zn. Los resultados indican que el pH no varió entre las situaciones estudiadas; los valores de CO disminuyeron (40% con la intensificación de la agricultura; la concentración de B y Zn se redujo en un 50% de la condición prístina a los lotes con larga historia agrícola; el Cu no sufrió alteraciones; Fe y Mn no muestran una tendencia clara de cambio en función del uso del suelo. En algunos casos podrían ocurrir deficiencias de Zn, por lo que debería controlarse rutinariamente su concentración, especialmente en los sistemas intensivos, para asegurar una disponibilidad adecuada a las necesidades de los cultivos. En todos los sistemas de uso analizados los tenores de micronutrientes presentaron elevada variabilidad.The studies related to the concentration and bioavailability of soil micronutrients are very limited for the central region of Santa Fe province, reason for which the objectives of the current research were: a to determine

Los Alamos National Laboratory Modular Pumped Hydro Feasibility Study for Santa Fe Community College

Energy Technology Data Exchange (ETDEWEB)

Bibeault, Mark Leonide [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-04-21

Report on the Economic Energy Assessment for a community college in Santa Fe, New Mexico. Report shows graphically the demand for energy in the month of September, and illustrates the production of electricity as it goes onto the grid for use.

Discovery of South American suckermouth armored catfishes (Loricariidae, Pterygoplichthys spp.) in the Santa Fe River drainage, Suwannee River basin, USA

Science.gov (United States)

Nico, Leo G.; Butt, Peter L.; Johnston, Gerald R.; Jelks, Howard L.; Kail, Matthew; Walsh, Stephen J.

2012-01-01

We report on the occurrence of South American suckermouth armored catfishes (Loricariidae) in the Suwannee River basin, southeastern USA. Over the past few years (2009-2012), loricariid catfishes have been observed at various sites in the Santa Fe River drainage, a major tributary of the Suwannee in the state of Florida. Similar to other introduced populations of Pterygoplichthys, there is high likelihood of hybridization. To date, we have captured nine specimens (270-585 mm, standard length) in the Santa Fe River drainage. One specimen taken from Poe Spring best agrees with Pterygoplichthys gibbiceps (Kner, 1854) or may be a hybrid with either P. pardalis or P. disjunctivus. The other specimens were taken from several sites in the drainage and include seven that best agree with Pterygoplichthys disjunctivus (Weber, 1991); and one a possible P. disjunctivus x P. pardalis hybrid. We observed additional individuals, either these or similar appearing loricariids, in Hornsby and Poe springs and at various sites upstream and downstream of the long (> 4 km) subterranean portion of the Santa Fe River. These specimens represent the first confirmed records of Pterygoplichthys in the Suwannee River basin. The P. gibbiceps specimen represents the first documented record of an adult or near adult of this species in open waters of North America. Pterygoplichthys disjunctivus or its hybrids (perhaps hybrid swarms) are already abundant and widespread in other parts of peninsular Florida, but the Santa Fe River represents a northern extension of the catfish in the state. Pterygoplichthys are still relatively uncommon in the Santa Fe drainage and successful reproduction not yet documented. However, in May 2012 we captured five adult catfish (two mature or maturing males and three gravid females) from a single riverine swallet pool. One male was stationed at a nest burrow (no eggs present). To survive the occasional harsh Florida winters, these South American catfish apparently use

Core drilling provides information about Santa Fe Group aquifer system beneath Albuquerque's West Mesa

Science.gov (United States)

Allen, B.D.; Connell, S.D.; Hawley, J.W.; Stone, B.D.

1998-01-01

Core samples from the upper ???1500 ft of the Santa Fe Group in the Albuquerque West Mesa area provide a first-hand look at the sediments and at subsurface stratigraphic relationships in this important part of the basin-fill aquifer system. Two major hydrostratigraphic subunits consisting of a lower coarse-grained, sandy interval and an overlying fine-grained, interbedded silty sand and clay interval lie beneath the water table at the 98th St core hole. Borehole electrical conductivity measurements reproduce major textural changes observed in the recovered cores and support subsurface correlations of hydrostratigraphic units in the Santa Fe Group aquifer system based on geophysical logs. Comparison of electrical logs from the core hole and from nearby city wells reveals laterally consistent lithostratigraphic patterns over much of the metropolitan area west of the Rio Grande that may be used to delineate structural and related stratigraphic features that have a direct bearing on the availability of ground water.

Apache, Santa Fe energy units awarded two Myanmar blocks

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper reports that Myanmar's state oil company has awarded production sharing contracts (PSCs) on two blocks to units of Apache Corp. and Santa Fe Energy Resources Inc., both of Houston. That comes on the heels of a report by County NatWest Woodmac that notes Myanmar's oil production, currently meeting less than half the country's demand, is set to fall further this year. 150 line km of new seismic data could be acquired and one well drilled. During the initial 2 year exploration period on Block EP-3, Apache will conduct geological studies and conduct at least 200 line km of seismic data

Irradiation Effect of Argon Ion on Interfacial Structure Fe(2nm/Si(tsi=0.5-2 nm Multilayer thin Film

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S. Purwanto

2010-04-01

Full Text Available Investigation includes formation of interfacial structure of Fe(2nm/Si(tSi= 0.5-2 nm multilayer thin film and the behavior of antiferromagnetic coupling between Fe layers due to Argon ion irradiation was investigated. [Fe(2nm/Si]30 multilayers (MLs with a thickness of Si spacer 0.5 - 2 nanometer were prepared on n-type (100 Si substrate by the helicon plasma sputtering method. Irradiation were performed using 400keV Ar ion to investigate the behavior of magnetic properties of the Fe/Si MLs. The magnetization measurements of Fe/Si MLs after 400keV Ar ion irradiation show the degradation of antiferromagnetic behavior of Fe layers depend on the ion doses. The Magnetoresistance (MR measurements using by Four Point Probe (FPP method also confirm that MR ratio decrease after ion irradiation. X-ray diffraction (XRD patterns indicate that the intensity of a satellite peak induced by a superlattice structure does not change within the range of ion dose. These results imply that the surface of interface structures after ion irradiation become rough although the layer structures are maintained. Therefore, it is considered that the MR properties of Fe/Si MLs also are due to the metallic superlattice structures such as Fe/Cr and Co/Cu MLs.

Usando patrones de biodiversidad para la evaluación y diseño de áreas protegidas: las serpientes de la provincia de Santa Fe (Argentina como ejemplo Using biodiversity patterns for assessment and design protected areas: snakes of Santa Fe province (Argentina as example

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VANESA ARZAMENDIA

2004-06-01

Full Text Available Las serpientes son usualmente muy perseguidas por el hombre y poco consideradas en estrategias de conservación de la biodiversidad, siendo las áreas protegidas esenciales para su preservación. Se analizaron los patrones de riqueza y biogeográficos de las serpientes de Santa Fe, Argentina, para priorizar áreas para su conservación y evaluar si las reservas existentes coinciden con ellas. Los patrones de diversidad y distribución fueron establecidos mediante el análisis de 2.532 especímenes de ofidios de Santa Fe, obtenidos en muestreos de campo y revisión de colecciones, complementados con registros bibliográficos y un banco de datos regional de 8.000 ejemplares. Se determinaron las áreas de endemismos de serpientes, las que fueron comparadas con las divisiones fitogeográficas. Se dividió Santa Fe en 16 celdas de un grado de latitud y longitud, para comparar su riqueza, similitud y complementariedad, aplicándose un método para priorizar áreas de conservación según la riqueza y el valor de conservación de cada taxón. La riqueza de especies en Santa Fe aumenta con la disminución de la latitud y longitud en relación con un gradiente de aumento de temperatura y precipitaciones anuales promedio. En consecuencia las celdas ubicadas en el extremo nordeste poseen la mayor riqueza (conteniendo 84 % de las especies y las celdas ubicadas en el extremo suroeste la menor riqueza (20 %. Todas las celdas atravesadas por el río Paraná tienen una mayor riqueza que las celdas contiguas, probablemente, debido al efecto de este río como corredor de especies tropicales y subtropicales. Se definieron cinco áreas de endemismos, cuatro de ellas coinciden con una o dos divisiones fitogeográficas y son relevantes en análisis de conservación por tener especies exclusivas. El análisis de similitud entre celdas muestra tres grupos mayores, "noroeste", "noreste-centro" y "sur", que coinciden con tres áreas de endemismos. El análisis conjunto

High temperature annealing of fission tracks in fluorapatite, Santa Fe Springs oil field, Los Angeles Basin, California

Science.gov (United States)

Naeser, Nancy D.; Crowley, Kevin D.; McCulloh, Thane H.; Reaves, Chris M.; ,

1990-01-01

Annealing of fission tracks is a kinetic process dependent primarily on temperature and to a laser extent on time. Several kinetic models of apatite annealing have been proposed. The predictive capabilities of these models for long-term geologic annealing have been limited to qualitative or semiquantitative at best, because of uncertainties associated with (1) the extrapolation of laboratory observations to geologic conditions, (2) the thermal histories of field samples, and (3) to some extent, the effect of apatite composition on reported annealing temperatures. Thermal history in the Santa Fe Springs oil field, Los Angeles Basin, California, is constrained by an exceptionally well known burial history and present-day temperature gradient. Sediment burial histories are continuous and tightly constrained from about 9 Ma to present, with an important tie at 3.4 Ma. No surface erosion and virtually no uplift were recorded during or since deposition of these sediments, so the burial history is simple and uniquely defined. Temperature gradient (???40??C km-1) is well established from oil-field operations. Fission-track data from the Santa Fe Springs area should thus provide one critical field test of kinetic annealing models for apatite. Fission-track analysis has been performed on apatites from sandstones of Pliocene to Miocene age from a deep drill hole at Santa Fe Springs. Apatite composition, determined by electron microprobe, is fluorapatite [average composition (F1.78Cl0.01OH0.21)] with very low chlorine content [less than Durango apatite; sample means range from 0.0 to 0.04 Cl atoms, calculated on the basis of 26(O, F, Cl, OH)], suggesting that the apatite is not unusually resistant to annealing. Fission tracks are preserved in these apatites at exceptionally high present-day temperatures. Track loss is not complete until temperatures reach the extreme of 167-178??C (at 3795-4090 m depth). The temperature-time annealing relationships indicated by the new data

CATÓLICOS EN LA PRENSA PROFANA. NUEVA ÉPOCA FRENTE AL REFORMISMO LIBERAL, SANTA FE, 1920-1923

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Diego A. Mauro

2008-01-01

Full Text Available El presente trabajo se sitúa en el contexto del proceso de reforma de la constitucional de la provincia de Santa Fe en torno al año 1921. Los proyectos reformistas de tendencia liberal y laicista condujeron a un enfrentamiento directo con la Iglesia Católica que recorrió transversalmente las identidades partidarias. Católicos y reformistas marcharon por las calles de Santa Fe e hicieron de la prensa uno de sus campos de batalla. En este artículo se analizará la estrategia seguida por publicistas y columnistas católicos en las intervenciones realizadas en el diario Nueva Época entre 1920 y 1923. Su participación en este medio les permitió conducir eficazmente disputas de sentido en la esfera pública y proyectar sus posiciones más allá de los circuitos propiamente católicos.

Genetics of leaf rust resistance in the hard red winter wheat cultivars Santa Fe and Duster

Science.gov (United States)

Leaf rust caused by Puccinia triticina is a common and important disease of hard red winter wheat in the Great Plains of the United States. The hard red winter wheat cultivars 'Santa Fe' and 'Duster' have had effective leaf rust resistance since their release in 2003 and 2006, respectively. Both cul...

Susan Magoffin’s Santa Fe Days in 1846: The Value of Testimony Les journées de Santa Fé en 1846 de Susan Magoffin : la valeur du témoignage

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Susanne Berthier-Foglar

2009-11-01

Full Text Available Susan Magoffin, la jeune épouse d’un commerçant de la piste de Santa Fe, accompagna son mari en 1846 pour un voyage où la caravane suivait de près l’Armée de l’Ouest et pendant lequel elle tint un journal. Cet article traite des 37 jours que dura la pause de la caravane à Santa Fe et aborde plus spécifiquement la façon dont l’auteur appréhendait l’altérité dans un environnement inhabituel et parfois dangereux. Pour apprécier la valeur du témoignage, je combine une analyse du discours avec une évaluation statistique du contenu. La description, parfois naïve, de Santa Fe sous l’occupation américaine illustre les raisons de la guerre contre le Mexique. En tant qu’agent de la destinée manifeste, Susan Magoffin admirait le général Kearny en lui attribuant des qualités surhumaines et en participant à ses efforts de propagande. Alors qu’elle était enracinée dans sa classe et sa culture, elle voyait la population mexicaine et les Amérindiens avec un esprit ouvert bien que ses motifs pour apprendre l’espagnol, ainsi que le métier de commerçante, avaient une fonction plus prosaïque.

Proceedings of the neutrons in biology conference, Santa Fe, NM, October 1994

International Nuclear Information System (INIS)

Schoenborn, B.P.

1994-01-01

This volume provides the proceedings for the Neutrons in Biology Conference held in Sante Fe, New Mexico October 1994. The volume is composed of full papers authored by the presenters at the conference. The sessions by which the presentations were organized are entitled Neutron Anatomy, Neutron Sources, Neutron Instrumentation, Small Angle Scattering, Membrane Structures and Dynamics, Protein Structures, Fiber Diffraction, and New Analysis and Experimental Techniques. Each paper has been separately indexed and abstracted for the database

Proceedings of the neutrons in biology conference, Santa Fe, NM, October 1994

Energy Technology Data Exchange (ETDEWEB)

Schoenborn, B.P.

1994-12-31

This volume provides the proceedings for the Neutrons in Biology Conference held in Sante Fe, New Mexico October 1994. The volume is composed of full papers authored by the presenters at the conference. The sessions by which the presentations were organized are entitled Neutron Anatomy, Neutron Sources, Neutron Instrumentation, Small Angle Scattering, Membrane Structures and Dynamics, Protein Structures, Fiber Diffraction, and New Analysis and Experimental Techniques. Each paper has been separately indexed and abstracted for the database.

Knowledge, attitudes and practices (KAP) regarding leptospirosis among residents of riverside settlements of Santa Fe, Argentina.

Science.gov (United States)

Ricardo, Tamara; Bergero, Laura C; Bulgarella, Esteban P; Previtali, M Andrea

2018-05-01

Leptospirosis is a global and re-emerging zoonotic disease caused by Leptospira spirochetes that are shed into the environment by infected animals. Humans can get infected via contact with animal hosts or contaminated environment. In Argentina, the highest annual incidences were reported in the province of Santa Fe, where epidemic outbreaks occurred during flooding events. This study examined the knowledge, attitudes and practices (KAP) regarding leptospirosis among residents of riverside slum settlements from Santa Fe after a major flood. A cross-sectional questionnaire was administered to 113 residents of 3 riverside settlements from Santa Fe. The influence of knowledge and attitudes regarding leptospirosis on the likelihood that an individual will use preventive practices were evaluated using linear mixed-effects models. The majority of respondents (83.2%) had previously heard about leptospirosis; however specific knowledge about leptospirosis was limited. The results of the modeling efforts, show that the likelihood of using preventive practices was associated with having greater knowledge score, but not with more positive attitudes. We also found that females were more likely to use safer practices than males. Even though the majority of respondents had heard about leptospirosis, a high percentage of them had limited knowledge regarding the severity of the disease and its prevalence in the region. Our results suggest that public health interventions in these riverside communities should focus on educating the public on the multiple dimensions of leptospirosis in order to attain greater adherence to preventive practices instead of intending to change the perceptions or attitudes towards the disease, which did not have a significant influence. The key challenge lies in identifying effective strategies to reach the high risk group for leptospirosis here that is male fishermen, who spend most of the time in precarious campsites on the river islands.

78 FR 64909 - Southwestern Region: Invasive Plant Control Project, Carson and Santa Fe National Forests, New...

Science.gov (United States)

2013-10-30

... the following instructions: (1) Complete the analysis of effects on the Management Indicator Species... forest: Carson Forest Supervisor's Office, 208 Cruz Alta Road, Taos, NM 87571, Attn: Planning; or Santa... and each will prepare a separate record of decision. Importance of Public Participation in Subsequent...

Social, cultural, and economic aspects of livestock ranching on the Santa Fe and Carson National Forests

Science.gov (United States)

Alice M. McSweeney; Carol Raish

2012-01-01

We examined the cultural, social, and economic aspects of livestock operations of ranchers who have Federal grazing permits (called permittees) on the Santa Fe and Carson National Forests of northern New Mexico. This study was an expansion of the 2003 pilot study and was designed to provide much-needed information concerning the culture and economic practices of the...

Cointegración y Simetrías en Precios. El Caso del Dulce de Leche en Santa Fe y Rosario

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E. D. Guiguet

2005-12-01

Full Text Available Este estudio tiene como objetivo evaluar la forma en que están cointegrados los precios minoristas de un producto típico argentino como es el dulce de leche, y el de su insumo básico, la leche cruda, en los mercados de Santa Fe y Rosario en el período 1996-2005, y la simetría en su ajuste de corto plazo. Se utiliza un análisis de cointegración no lineal con los modelos TAR y MTAR. Los resultados confirman la existencia de cointegración en ambas ciudades, y asimetría en los ajustes en el corto plazo en Santa Fe. Además que la transmisión de los cambios de precios es más rápida cuando los márgenes de comercialización disminuyen que cuando se incrementan.

Imágenes especulares: Educación, laicidad y catolicismo en Santa Fe, 1900-1940

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Diego A. Mauro

2009-01-01

Full Text Available El presente trabajo se interroga en torno a las relaciones entre catolicismo y laicismo en el terreno educativo. Se pregunta, en particular, sobre la consistencia historiográfica de las imágenes construidas como reflejo de la tesis del "renacimiento católico". Según estos cuadros, la contracara del denominado "renacimiento" habría sido el ocaso de una "Argentina laica y liberal", consagrada en términos educativos en la ley 1420. Partiendo de estas visiones especulares, el texto se propone discutir, para el caso de la provincia de Santa Fe, algunos de los argumentos esgrimidos tras la "postal laicista", a la luz de los debates abiertos en torno a las teorías de la "secularización" y de la "modernidad".The present work studies the relationships between catholicism and laicism in the educational field. In particular, it wonders about the historiographic consistency of the images built as a reflection of the "catholic rebirth" thesis. According to these frames, the counterpart of the denominated "rebirth" would have been the decline of a "lay and liberal Argentina", established in educational terms in the 1420 law. Starting from these views, the text discusses, for the Santa Fe county case, some of the arguments fenced behind the "lay postal", in light of the opened debates around the theories of the "secularization" and of the "modernity".

Distribution of inorganic arsenic species in groundwater from Central-West Part of Santa Fe Province, Argentina

International Nuclear Information System (INIS)

Sigrist, Mirna; Albertengo, Antonela; Brusa, Lucila; Beldoménico, Horacio; Tudino, Mabel

2013-01-01

Highlights: • Study on inorganic arsenic species in groundwater for drinking in Santa Fe Argentina. • This information is currently scarce or absent in the region. • An analytical methodology based on SPE-FI-HGAAS coupling was used for speciation. • Information is given for a more accurate interpretation of the toxicological impact. - Abstract: The distribution of inorganic arsenic species in groundwater used as drinking water supply by the peri-urban and rural population from central-western area of Santa Fe Province, Argentina, was studied. An analytical methodology based on an online system of atomic absorption spectrometry with hydride generation and flow injection (FI-HGAAS) was used for total inorganic arsenic determination. For speciation purposes, the distinction between As(V) and As(III) was performed through the on line coupling of FI-HGAAS to a solid phase system based on an anionic exchanger able to retain As(V) as oxyanion, allowing As(III) to be selectively determined. The concentration of As(V) was calculated as the difference between total arsenic and As(III) concentrations. Effects of matrix interference due to the nonselective behavior of the exchange resins were carefully laid. Results for 59 samples collected from 27 localities showed an almost exclusive predominance of pentavalent forms

Modeling 13.3nm Fe XXIII Flare Emissions Using the GOES-R EXIS Instrument

Science.gov (United States)

Rook, H.; Thiemann, E.

2017-12-01

The solar EUV spectrum is dominated by atomic transitions in ionized atoms in the solar atmosphere. As solar flares evolve, plasma temperatures and densities change, influencing abundances of various ions, changing intensities of different EUV wavelengths observed from the sun. Quantifying solar flare spectral irradiance is important for constraining models of Earth's atmosphere, improving communications quality, and controlling satellite navigation. However, high time cadence measurements of flare irradiance across the entire EUV spectrum were not available prior to the launch of SDO. The EVE MEGS-A instrument aboard SDO collected 0.1nm EUV spectrum data from 2010 until 2014, when the instrument failed. No current or future instrument is capable of similar high resolution and time cadence EUV observation. This necessitates a full EUV spectrum model to study EUV phenomena at Earth. It has been recently demonstrated that one hot flare EUV line, such as the 13.3nm Fe XXIII line, can be used to model cooler flare EUV line emissions, filling the role of MEGS-A. Since unblended measurements of Fe XXIII are typically unavailable, a proxy for the Fe XXIII line must be found. In this study, we construct two models of this line, first using the GOES 0.1-0.8nm soft x-ray (SXR) channel as the Fe XXIII proxy, and second using a physics-based model dependent on GOES emission measure and temperature data. We determine that the more sophisticated physics-based model shows better agreement with Fe XXIII measurements, although the simple proxy model also performs well. We also conclude that the high correlation between Fe XXIII emissions and the GOES 0.1-0.8nm band is because both emissions tend to peak near the GOES emission measure peak despite large differences in their contribution functions.

Liberalismo, democracia y catolicismo en Argentina. La reforma constitucional de 1921 y las identidades políticas. Santa Fe 1920-1923

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Diego A. Mauro

2008-11-01

Full Text Available El presente trabajo reconstruye el proceso de reforma de la Constitución de la Provincia de Santa Fe entre 1920 y 1923 y su impacto sobre el sistema político y la opinión pública. El grado de movilización social de los militantes católicos y liberales en las calles de Santa Fe y Rosario, así como la alta densidad de conflictos, acuerdos y rupturas entre los partidos y sus inestables facciones en el seno de la Constituyente hicieron de la coyuntura un potente matrizador de las identidades políticas. El artículo intenta paralelamente acercarse de manera aproximatoria a algunos de los modos en que la política filtró las identidades de los sectores populares y alimentó los imaginarios sociales críticos sobre la democracia liberal.

Investigation of the 234U/238U disequilibrium in the natural waters of the Santa Fe River basin north-central Florida

International Nuclear Information System (INIS)

Briel, L.I.

1976-01-01

Typical surface water masses in the Santa Fe basin are characterized by a 238 U concentration of 0.224 +- .014 ppB and a 234 U/ 238 U activity ratio of 1.081 +- .038. The Floridan aquifer in this area is represented by at least two distinct regimes of ground water. The effluent from the Poe Springs group has a nominal uranium concentration of 0.938 +- .014 ppB and an activity ratio of 0.900 +- .012, while the effluent from the Ichetucknee Springs group has a nominal uranium concentration of 0.558 +- .018 ppB and an activity ratio of 0.707 +- .022. The effluent from ten additional springs in the Santa Fe system can be represented by hypothetical mixtures of these two ground water regimes and a hypothetical surface water component, which may reflect the extent of local recharge to the aquifer in different parts of the basin

Mortality of Plutella xylostella (Lepidoptera, Plutellidae by parasitoids in the Province of Santa Fe, Argentina

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Isabel Bertolaccini

2011-09-01

Full Text Available Mortality of Plutella xylostella (Lepidoptera, Plutellidae by parasitoids in the Province of Santa Fe, Argentina. Plutella xylostella (Linnaeus, 1758 (Lepidoptera, Plutellidae larvae cause severe economic damage on cabbage, Brassica oleracea L. variety capitata (Brassicaceae, in the horticultural fields in the Province of Santa Fe, Argentina. Overuse of broad spectrum insecticides affects the action of natural enemies of this insect on cabbage. The objectives of this work were to identify the parasitoids of P. xylostella and to determine their influence on larva and pupa mortality. Weekly collections of larvae and pupae were randomly conducted in cabbage crops during spring 2006 and 2007. The immature forms collected were classified according to their developmental stage: L1 and L2 (Ls = small larvae, L3 (Lm = medium larvae, L4 (Ll = large larvae, pre-pupae and pupae (P. Each individual was observed daily in the laboratory until the adult pest or parasitoid emergence. We identified parasitoids, the number of instar and the percentage of mortality of P. xylostella for each species of parasitoid. Parasitoids recorded were: Diadegma insulare (Cresson, 1875 (Hymenoptera, Ichneumonidae, Oomyzus sokolowskii (Kurdjumov, 1912 (Hymenoptera, Eulophidae, Cotesia plutellae (Kurdjumov, 1912 (Hymenoptera, Braconidae and an unidentified species of Chalcididae (Hymenoptera. Besides parasitoids, an unidentified entomopathogenic fungus was also recorded in 2006 and 2007. In 2006, the most successful parasitoids were D. insulare and O. sokolowskii, while in 2007 only D. insulare exerted a satisfactory control and it attacked the early instars of the pest.

Estudio epidemiológico de los casos de triquinelosis registrados en la provincia de Santa Fe, Argentina, 1998-2009 Epidemiological study of recorded trichinosis cases in Santa Fe Province, Argentina, 1998-2009

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Gabriel J. Sequeira

2013-05-01

Full Text Available OBJETIVO: Caracterizar desde los puntos de vista epidemiológico, clínico y de laboratorio los casos y brotes de triquinelosis que se registraron en la provincia de Santa Fe, Argentina, entre 1998 y 2009. MÉTODOS: Se analizaron 1 519 fichas epidemiológicas de personas que presentaron síntomas y signos compatibles con triquinelosis en la provincia de Santa Fe en el período 1998-2009. Se realizó el análisis estadístico descriptivo de la información contenida en las fichas epidemiológicas y los resultados clínicos y de laboratorio; se aplicó el análisis bifactorial para determinar las posibles asociaciones con factores epidemiológicos y ambientales. RESULTADOS: Se encontraron síntomas de triquinelosis en 1 276 casos; 372 cumplían la definición de caso clínico y 224 muestras resultaron positivas por inmunofluorescencia indirecta, independientemente de su clasificación como caso clínico. Se identificaron 27 brotes que involucraron a 1 157 casos en ocho departamentos, con mayor frecuencia en el centro y el sur de la provincia. La distribución anual de los casos asociados epidemiológicamente entre sí fue heterogénea, con una mayor frecuencia en el período 2000-2003 y en los meses de agosto a octubre. Hubo mayor probabilidad de enfermar cuando se consumieron productos de fuentes informales (OR = 3,69; P = 0,014 y en las áreas rurales (OR = 1,799; P = 0,011. El período de incubación de la enfermedad (mediana fue de 12 días. Las personas que consumieron carne de cerdo o sus derivados tuvieron 2,06 veces más riesgo de enfermar que las que no la consumieron. CONCLUSIONES: El mayor número de brotes ocurrió en los departamentos más poblados y con mayor producción porcina. Se deben diseñar acciones específicas de prevención y control de la enfermedad en esos departamentos. Se debe considerar el análisis epidemiológico de riesgos al evaluar, gestionar y comunicar los riesgos sanitarios de triquinelosis.OBJECTIVE: To

Magnetic Properties and Microstructure of FeOx/Fe/FePt and FeOx/FePt Films

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Jai-Lin Tsai

2013-01-01

Full Text Available The Fe(6 nm/FePt film with perpendicular magnetization was deposited on the glass substrate. To study the oxygen diffusion effect on the coupling of Fe/FePt bilayer, the plasma oxidation with 0.5~7% oxygen flow ratio was performed during sputtered part of Fe layer and formed the FeOx(3 nm/Fe(3 nm/FePt trilayer. Two-step magnetic hysteresis loops were found in trilayer with oxygen flow ratio above 1%. The magnetization in FeOx and Fe/FePt layers was decoupled. The moments in FeOx layer were first reversed and followed by coupled Fe/FePt bilayer. The trilayer was annealed again at 500°C and 800°C for 3 minutes. When the FeOx(3 nm/Fe(3 nm/FePt trilayer was annealed at 500°C, the layers structure was changed to FeOx(6 nm/FePt bilayer due to oxygen diffusion. The hard-magnetic FeOx(6 nm/FePt film was coupled with single switching field. The FeOx/(disordered FePt layer structure was observed with further annealing at 800°C and presented soft-magnetic loop. In summary, the coupling between soft-magnetic Fe, FeOx layer, and hard-magnetic L10 FePt layer can be controlled by the oxygen diffusion behavior, and the oxidation of Fe layer was tuned by the annealing temperature. The ordered L10 FePt layer was deteriorated by oxygen and became disordered FePt when the annealed temperature was up to 800°C.

An integrated approach to investigate the hydrological behavior of the Santa Fe River Basin, north central Florida

Science.gov (United States)

Vibhava, F.; Graham, W. D.; De Rooij, R.; Maxwell, R. M.; Martin, J. B.; Cohen, M. J.

2011-12-01

The Santa Fe River Basin (SFRB) consists of three linked hydrologic units: the upper confined region (UCR), semi-confined transitional region (Cody Escarpment, CE) and lower unconfined region (LUR). Contrasting geological characteristics among these units affect streamflow generation processes. In the UCR, surface runoff and surficial stores dominate whereas in the LCR minimal surface runoff occurs and flow is dominated by groundwater sources and sinks. In the CE region the Santa Fe River (SFR) is captured entirely by a sinkhole into the Floridan aquifer, emerging as a first magnitude spring 6 km to the south. In light of these contrasting hydrological settings, developing a predictive, basin scale, physically-based hydrologic simulation model remains a research challenge. This ongoing study aims to assess the ability of a fully-coupled, physically-based three-dimensional hydrologic model (PARFLOW-CLM), to predict hydrologic conditions in the SFRB. The assessment will include testing the model's ability to adequately represent surface and subsurface flow sources, flow paths, and travel times within the basin as well as the surface-groundwater exchanges throughout the basin. In addition to simulating water fluxes, we also are collecting high resolution specific conductivity data at 10 locations throughout the river. Our objective is to exploit hypothesized strong end-member separation between riverine source water geochemistry to further refine the PARFLOW-CLM representation of riverine mixing and delivery dynamics.

EVALUACIÓN DE Salvia hispanica L. CULTIVADA EN EL SUR DE SANTA FE (REPÚBLICA ARGENTINA)

OpenAIRE

Héctor Busilacchi; Mirta Quiroga; Mirian Bueno; Osvaldo Di Sapio; Voykos Flores; Cecilia Severin

2013-01-01

Salvia hispanica L. (chía)-Lamiaceae, es una especie de interés dietario-medicinal, fuente de ácidos grasos Omega-6 y Omega-3, proteínas, antioxidantes y fibras solubles e insolubles. No existen suficientes datos disponibles sobre las posibilidades de llevar el cultivo a término en el sur de la provincia de Santa Fe, considerando principalmente la incidencia de heladas tardías. Ante la escasez de información sobre el cultivo a campo de S. hispanica en diferentes regiones de Argentina, teni...

Espanola/Canjilon Pilot Study: Economic, social, and cultural aspects of public land grazing on the Santa Fe and Carson National Forests

Science.gov (United States)

Carol Raish

1999-01-01

Many of the livestock grazing permittees on the Carson and Santa Fe National Forests in northern New Mexico are descendants of Hispanic settlers who have farmed and ranched in the region for 400 years. Much of the permitted land was formerly owned or used by local communities under Spanish and Mexican land grants. Cultural differences and historical issues of...

Floodplain Mapping for Santa Fe County, NM

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — The Floodplain Mapping study deliverables depict and quantify the flood risks for the study area. The primary risk classifications used are the...

The Great Southwest of the Fred Harvey Company and the Santa Fe Railway, edited by Marta Weigle and Barbara A. Babcock. The Heard Museum, Pheonix (printed by The University of Arizona Press, Tucson, for The Heard Museum, 1996

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Douglas R. Givens

1997-11-01

Full Text Available One of the more colorful eras in American Southwestern archaelogy is reflected in The Great Southwest of the Fred Harvey Company and the Santa Fe Railway. Marta Weigle and Barbara A. Babcock, editors of the volume, have done a superb job weaving in early Southwestern archaeological activities with the role of the Fred Harvey Company and the Santa Fe Railway in bring the American Southwest to those "east of the Mississippi River". Many early Southwestern archaeologists made their way throughout the Southwest on the Santa Fe Railway while the "outposts of civilization" that the Fred Harvey Company provided in many railroad stations served as a " bit of home" to the traveler. This book describes the collaboration of both Fred Harvey and the Santa Fe Railroad tourism in the American Southwest and provides an excellent look into the Native American artists and their comumnities which were transformed on a massive scale by the Fred Harvey Company as it bought, sold, and popularized Native American art. Also part of the volume is an excellent discussion of the network of major museums that hold art collections which were purchased through the Harvey Company's Indian Department.

Guerra, imperio y violencia en la Audiencia de Santa Fe, Nuevo Reino de Granada, 1580-1620

OpenAIRE

Córdoba Ochoa, Luis Miguel

2013-01-01

Programa de Doctorado en Estudios sobre Europa, el Mundo Mediterráneo y su Difusión Atlántica: Élites y Procesos de Convergencia Cultural y Económica, 1450-1900 En la tesis se analizan los procesos mediante los cuales los españoles adquirieron, construyeron y reinterpretaron los conocimientos sobre la población indígena y sobre los recursos de los territorios bajo la jurisdicción de la Audiencia de Santa Fe -hoy Bogotá-, en el Nuevo Reino de Granada durante el siglo XVI, con el propósito d...

Magnetic rotational hysteresis study on spherical 85-160 nm Fe3O4 particles

Science.gov (United States)

Schmidbauer, E.

1988-05-01

Rotational hysteresis losses Wr were determined as a function of magnetic field H for dispensed spherical Fe3O4 particles of mean grain sizes 85 nm, 127 nm and 162 nm between 78 K and 294 K. The observed Wr-H curves are compared with theoretical curves for single domain particles. The analysed particles reveal centers of high magnetic anisotropy. Such centers can be of importance during the generation of a thermoremanent magnetization, as they may be the origin of enhanced magnetic stability.

Olga Cossettini in the labyrinth of the political sociability of Santa Fe (Argentina, 1937-1943

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Sandra Rita Fernandez

2015-01-01

Full Text Available This article's intent is to take into account the web of acquaintanceships that teacher and pedagogue V. Olga Cossettini developed during the 1930's and early 1940's, thanks to which she was able to organize her educational project in the official educational structures of Santa Fe province of Argentina. In a historical context marked by intervention and fraud, we intend to historically locate this educator, allowing the integral comprehension of said historical context's complexities; and also allowing the interpretation of what an experience such as Escuela Serena meant in a political climate that, a priori, one would have thought of as less than ideal for this type of pedagogical practices.

Channel bed particle size distribution procedure used to evaluate watershed cumulative effects for range permit re-issuance on the Santa Fe National Forest

Science.gov (United States)

Bruce Sims; Jim Piatt; Lee Johnson; Carol Purchase; John Phillips

1996-01-01

Personnel on the Santa Fe National Forest used methodologies adapted from Bevenger and King (1995) to collect base line particle size data on streams within grazing allotments currently scheduled for permit reissuance. This information was used to determine the relative current health of the watersheds as well as being used in the development of potential alternatives...

Conferences, workshops, trainings

Science.gov (United States)

Goals Recycling Green Purchasing Pollution Prevention Reusing Water Resources Environmental Management . Mar 1 Wed 8:00 AM Cosmic Rays, Pulsar Nebulae and Dark Matter La Fonda Hotel, Santa Fe, NM The purpose Quantum Matter La Fonda Hotel - 100 East San Francisco Street, Santa Fe, NM The purpose of this workshop

MFM study of NdFeB and NdFeB/Fe/NdFeB thin films

International Nuclear Information System (INIS)

Gouteff, P.C.; Folks, L.; Street, R.

1998-01-01

Domain structures of NdFeB thin films, ranging in thickness between 1500 and 29 nm, have been studied qualitatively by magnetic force microscopy (MFM). Samples were prepared using a range of sputtering conditions resulting in differences in properties such as texture, coercivity and magnetic saturation. MFM images of all the films showed extensive interaction domain structures, similar to those observed in nanocrystalline bulk NdFeB. An exchange-coupled NdFeB/Fe/NdFeB trilayer with layer thicknesses 18 nm/15 nm/18 nm, respectively, was also examined using MFM. (orig.)

Biologic origin of iron nodules in a marine terrace chronosequence, Santa Cruz, California

Science.gov (United States)

Schulz, M.S.; Vivit, D.; Schulz, C.; Fitzpatrick, J.; White, A.

2010-01-01

The distribution, chemistry, and morphology of Fe nodules were studied in a marine terrace soil chronosequence northwest of Santa Cruz, California. The Fe nodules are found at depths hyphae throughout the nodules, including organic structures incorporating fine-grained Fe oxides. The fine-grained nature of the Fe oxides was substantiated by M??ssbauer spectroscopy. Our microscopic observations led to the hypothesis that the nodules in the Santa Cruz terrace soils are precipitated by fungi, perhaps as a strategy to sequester primary mineral grains for nutrient extraction. The fungal structures are fixed by the seasonal wetting and dry cycles and rounded through bioturbation. The organic structures are compacted by the degradation of fungal C with time. ?? Soil Science Society of America. All rights reserved.

Earthquake scenario and probabilistic ground-shaking hazard maps for the Albuquerque-Belen-Santa Fe, New Mexico, corridor

Science.gov (United States)

Wong, I.; Olig, S.; Dober, M.; Silva, W.; Wright, D.; Thomas, P.; Gregor, N.; Sanford, A.; Lin, K.-W.; Love, D.

2004-01-01

New Mexico's population is concentrated along the corridor that extends from Belen in the south to Española in the north and includes Albuquerque and Santa Fe. The Rio Grande rift, which encompasses the corridor, is a major tectonically, volcanically, and seismically active continental rift in the western U.S. Although only one large earthquake (moment magnitude (M) ≥ 6) has possibly occurred in the New Mexico portion of the rift since 1849, paleoseismic data indicate that prehistoric surface-faulting earthquakes of M 6.5 and greater have occurred on aver- age every 400 yrs on many faults throughout the Rio Grande rift.

Frecuencia de parásitos intestinales en pacientes VIH+ en la ciudad de Santa Fe de Bogotá

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Myriam Consuelo López

1999-01-01

Full Text Available The objective ofthe present work is to find frequency of intestinasl opportunistic parasites in a population of HIV + outpatients that assisted to the program of Sexual Transmited Diseases (STD in University Hospital San Juan de Dios at Santa Fe de Bogotá. Cryptosporidum sp. and lsospora belli were observed in 1% of patients. It is important to emphasize the low frequency of opportunistic parasites in this study. The highest prevelence corresponded to Endolimax-nana (15.1 % and Entamoeba coli  (13.2%. The frequency of nematodes is very low: unicinaria and Strongyloides stercoralis were presentn 1%.

Ferroelectricity down to at least 2 nm in multiferroic BiFeO3 epitaxial thin films

International Nuclear Information System (INIS)

Bea, H.; Fusil, S.; Bouzehouane, K.; Sirena, M.; Herranz, G.; Jacquet, E.; Contour, J.-P.; Barthelemy, A.; Bibes, M.

2006-01-01

We report here on the preservation of ferroelectricity down to 2 nm in BiFeO 3 ultrathin films. The electric polarization can be switched reversibly and is stable over several days. Our findings insight on the fundamental problem of ferroelectricity at low thickness and confirm the potential of BiFeO 3 as a lead-free ferroelectric and multiferroic material for nanoscale devices. (author)

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion.

Science.gov (United States)

Burleigh, Thomas D; Gierke, Casey G; Fredj, Narjes; Boston, Penelope J

2014-06-05

Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC). In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS), then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM). The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water.

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion

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Thomas D. Burleigh

2014-06-01

Full Text Available Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC. In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS, then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM. The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water.

Imágenes especulares: Educación, laicidad y catolicismo en Santa Fe, 1900-1940

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Diego A. Mauro

2009-01-01

Full Text Available El presente trabajo se interroga en torno a las relaciones entre catolicismo y laicismo en el terreno educativo. Se pregunta, en particular, sobre la consistencia historiográfica de las imágenes construidas como reflejo de la tesis del "renacimiento católico". Según estos cuadros, la contracara del denominado "renacimiento" habría sido el ocaso de una "Argentina laica y liberal", consagrada en términos educativos en la ley 1420. Partiendo de estas visiones especulares, el texto se propone discutir, para el caso de la provincia de Santa Fe, algunos de los argumentos esgrimidos tras la "postal laicista", a la luz de los debates abiertos en torno a las teorías de la "secularización" y de la "modernidad".

Vigilancia de la resistencia de Neisseria gonorrhoeae en un hospital de la provincia de Santa Fe, Argentina: 1997-2004 Resistance surveillance of Neisseria gonorrhoeae in a hospital in Santa Fe province, Argentina: 1997-2004

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E. De Los A. Méndez

2008-09-01

Full Text Available Se determinaron los fenotipos de resistencia caracterizados por la concentración inhibitoria mínima, la difusión con discos y la producción de β-lactamasa de 434 aislamientos de Neisseria gonorrhoeae obtenidos de pacientes atendidos en el Servicio de Enfermedades de Transmisión Sexual del Hospital Dr. José María Cullen, Santa Fe, Argentina. Se realizaron pruebas de sensibilidad a los siguientes antimicrobianos: penicilina, tetraciclina, ciprofloxacina, espectinomicina, azitromicina y ceftriaxona. A tres aislamientos resistentes a ciprofloxacina se les realizó electroforesis de campo pulsado. Se destacaron tres situaciones epidemiológicas de interés: en el año 1997, alta incidencia de aislamientos con resistencia plasmídica a tetraciclina (33,3%; en el período 2002-2004, un aumento significativo de la resistencia plasmídica a penicilina (9,7% a 34,8%; y en el año 2000, la emergencia de dos de los tres primeros aislamientos con resistencia a quinolonas del país. El primer aislamiento resistente a azitromicina en nuestro hospital emerge en el 2004. Este trabajo jerarquiza el rol del Laboratorio de Microbiología Clínica en la orientación del tratamiento empírico de la gonorrea.Resistance phenotypes characterized by minimum inhibitory concentration, disk diffusion and β-lactamase production were determined in 434 isolates from patients attending the Sexually Transmitted Disease Service at Dr. José María Cullen Hospital in Santa Fe, Argentina. Susceptibility tests to penicillin, tetracycline, ciprofloxacin, espectinomycin, azithromycin and ceftriaxone were performed. Pulsed-field gel electrophoresis was conducted made to on three ciprofloxacin-resistant isolates. Epidemiologically speaking, three interesting events should be highlighted: during 1997, plasmid-mediated high level tetracycline-resistant strains were observed (33.3%; from 2002 to 2004 a significant increase of plasmid-mediated penicillin-resistant strains was

Soft magnetic properties of hybrid ferromagnetic films with CoFe, NiFe, and NiFeCuMo layers

Energy Technology Data Exchange (ETDEWEB)

Choi, Jong-Gu [Eastern-western Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Hwang, Do-Guwn [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of); Rhee, Jang-Roh [Dept. of Physics, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Lee, Sang-Suk, E-mail: sslee@sangji.ac.kr [Dept. of Oriental Biomedical Engineering, Sangji University, Wonju 220-702 (Korea, Republic of)

2011-09-30

Two-layered ferromagnetic alloy films (NiFe and CoFe) with intermediate NiFeCuMo soft magnetic layers of different thicknesses were investigated to understand the relationship between coercivity and magnetization process by taking into account the strength of hard-axis saturation field. The thickness dependence of H{sub EC} (easy-axis coercivity), H{sub HS} (hard-axis saturation field), and {chi} (susceptibility) of the NiFeCuMo thin films in glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared using the ion beam deposition method was determined. The magnetic properties (H{sub EC}, H{sub HS}, and {chi}) of the ferromagnetic CoFe, NiFe three-layers with an intermediate NiFeCuMo super-soft magnetic layer were strongly dependent on the thickness of the NiFeCuMo layer.

Exchange bias variations of the seed and top NiFe layers in NiFe/FeMn/NiFe trilayer as a function of seed layer thickness

International Nuclear Information System (INIS)

Sankaranarayanan, V.K.; Yoon, S.M.; Kim, C.G.; Kim, C.O.

2005-01-01

Development of exchange bias at the seed and top NiFe layers in the NiFe (t nm)/FeMn(10 nm)/NiFe(5 nm) trilayer structure is investigated as a function of seed layer thickness, in the range of 2-20 nm. The seed NiFe layer shows maximum exchange bias at 4 nm seed layer thickness. The bias shows inverse thickness dependence with increasing thickness. The top NiFe layer on the other hand shows only half the bias of the seed layer which is retained even after the sharp fall in seed layer bias. The much smaller bias for the top NiFe layer is related to the difference in crystalline texture and spin orientations at the top FeMn/NiFe interface, in comparison to the bottom NiFe/FeMn interface which grows on a saturated NiFe layer with (1 1 1) orientation

Ethnoastronomy in the Multicultural Context of the Agricultural Colonies in Northern Santa Fe Province, Argentina

Science.gov (United States)

Mudrik, Armando

In this paper, we present a study about cultural astronomy among European colonists and their Argentinean descendants, in the context of a complex interaction between criollos, aboriginals and European colonists from different origins and religions, who settled in the northern area of the Argentinean province of Santa Fe, which is part of the southern Gran Chaco. These colonists arrived among waves of immigration occurring in Argentina in the second half of the nineteenth century and the first half of the twentieth century. Through ethnographic field research among these immigrants and their descendants, we carried out a survey of their astronomical representations and practices, and the connections of these with their social life and farming tasks. Through this we gained an insight as to how the astronomical ideas of immigrants, criollos and aboriginal groups influenced each other, generating a variety of new relations with the celestial realm.

75 FR 16493 - Announcement of Funding Awards for the Public and Indian Housing Family Self-Sufficiency Program...

Science.gov (United States)

2010-04-01

... Orleans..... LA 70122 68,000 Orleans. Jefferson Parish Housing 1718 Betty Street.... Marrero......... LA 70072 45,893 Authority. Shreveport Housing Authority. 2500 Line Avenue..... Shreveport...... LA 71104 36... Vista Street Santa Fe........ NM 87505 55,908 Authority. Santa Fe County Housing 52 Camino De Jacobo...

Economic, social, and cultural aspects of livestock ranching on the Española and Canjilon Ranger Districts of the Santa Fe and Carson National Forests: a pilot study

Science.gov (United States)

Carol Raish; Alice M. McSweeney

2003-01-01

The ranches of northern New Mexico, composed of land and livestock, are integral components of family and community life. This pilot study examines current economic, social, and cultural aspects of livestock operations owned by ranchers with Federal grazing permits (permittees) on the Canjilon and Española Ranger Districts of the Santa Fe and Carson National...

Edilicia pública en el Archivo Municipal de Santa Fe: El arquitecto Francisco Fábregas Vehil (1925-1934

Directory of Open Access Journals (Sweden)

Ana María Castañeda Becerra

2009-12-01

Full Text Available Santa Fe inicia la remodelación de su edilicia pública durante la Dictadura de Primo de Rivera a raíz de tres decisiones municipales: construir un local apropiado para las Escuelas, un nuevo Ayuntamiento, y modernizar la imagen de la ciudad ante la celebración de la Exposición Iberoamericana de Sevilla en 1929. El proyecto (Casa Consistorial, Mercado con Matadero, Escuelas, Pavimentación y Alcantarillado, y dos Lavaderos se encarga a la empresa “Técnica de Construcción, S.A” y a su arquitecto Francisco Fábregas Vehil, quien realizó los proyectos y dirigió las obras desde Sevilla y Barcelona hasta bien entrada la Segunda República.

Repressive frames: continuities and discontinuities in a case study. The Dirección General de Informaciones, province of Santa Fe, 1966-1991"

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Gabriela Águila

2013-04-01

Full Text Available The article analyzes an intelligence agency acting provincial level (province of Santa Fe, which was not part of the police or military orbit and worked steadily between 1966 and the early 90s. It discusses its objectives and functions, rules, structure and agents, their actions and practices, recording the continuities and changes experienced over its decades of existence. It aims to contribute to a study of a particular case the knowledge of one of the gray areas, perhaps the most opaque, the exercise of repression in Argentina: the performance of the intelligence services.

76 FR 28222 - Extension of the Public Review and Comment Period and Announcement of an Additional Public...

Science.gov (United States)

2011-05-16

... Independence Avenue, SW., Washington, DC 20585, or telephone 202-586-9438. For general information concerning... (GC-54), U.S. Department of Energy, 1000 Independence Avenue, SW., Washington, DC 20585; (202) 586..., at 5 p.m. to 9 p.m., Santa Fe Community College, Jemez Rooms, 6401 Richards Avenue, Santa Fe, NM. The...

A case of familial transmission of community-acquired methicillin-resistant Staphylococcus aureus carrying the lnu(A gene in Santa Fe city, Argentina Caso de transmisión familiar de Staphylococcus aureus resistente a la meticilina adquirido en la comunidad portador del gen lnu(A en la ciudad de Santa Fe, Argentina

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Emilce de los A Méndez

2012-12-01

Full Text Available Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA is increasingly recognized as an important pathogen causing skin and soft tissue infections as well as necrotizing pneumonia. We describe a case of familial transmission of CA-MRSA between a 6-month-old boy and his mother in Santa Fe City, Argentina. Both isolates showed an identical antimicrobial susceptibility profile, carried type IV SCCmec and harboured the pvl and the lnu(A genes. Isolates showed indistinguishable SmaI-PFGE patterns confirming their genetic relationship. These results corroborate the intrafamilial transmission of CA-MRSA and might associate this strain with the repetitive events of furunculosis within the family.Staphylococcus aureus resistente a la meticilina adquirido en la comunidad (SARM-AC es reconocido como un patógeno importante que causa infecciones de piel y partes blandas y neumonía necrotizante. Describimos un caso de transmisión familiar de SARM-AC entre un nino de 6 meses de edad y su madre en la ciudad de Santa Fe, Argentina. Ambos aislamientos mostraron idéntico perfil de sensibilidad a los antimicrobianos, tenían el SCCmec tipo IV, y contenían los genes pvl y lnu(A. Los aislamientos presentaron patrones de SmaI-PFGE indistinguibles entre sí, lo cual confirmó su relación genética. Estos resultados corroboran la transmisión intrafamiliar de SARM-AC; asimismo, este aislamiento podría asociarse con los eventos repetitivos de furunculosis en la familia.

Structural and magnetic properties of NdFeB and NdFeB/Fe films with Mo addition

Energy Technology Data Exchange (ETDEWEB)

Urse, M; Grigoras, M; Lupu, N; Chiriac, H, E-mail: urse@phys-iasi.ro [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)

2011-07-06

The influence of the Mo addition on the microstructure and magnetic properties of Nd-Fe-B and Nd-Fe-B/Fe films was studied. The coercivity is a key parameter in the control of technical performances of Nd-Fe-B films. A small amount of about 1 at.% Mo can enhance the coercivity of Nd-Fe-B film by controlling the growth of soft and hard magnetic grains. A coercivity of 22.1 kOe, a remanence ratio, M{sub r}/M{sub s}, of 0.83 and a maximum energy product of 8 MGOe were obtained for Ta/[NdFeBMo(1at.%)(540nm)/Ta films annealed at 650{sup 0}C for 20 minutes due to Mo precipitates formed at the Nd{sub 2}Fe{sub 14}B phase boundaries which prevent the nucleation and expansion of the magnetic domains. Simultaneous use of Mo as addition and the stratification of Nd-Fe-B-Mo films using Fe as spacer layer are important tools for the improvement of the hard magnetic properties of Nd-Fe-B films. The Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta multilayer film annealed at 620{sup 0}C exhibits an increase in the coercivity from 12.1 kOe to 22.8 kOe, in the remanence ratio from 0.77 to 0.80, and in the maximum energy product from 4.5 to 7.1 MGOe in comparison with Ta/Nd-Fe-B/Ta film. As compared to Ta/Nd-Fe-B/Ta film, the Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta film presents a decrease in the crystallization temperature of about 30{sup 0}C.

Inseguridad alimentaria en la ciudad de Santa Fe: percepción de los ciudadanos

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María Amalia Rosso

2015-01-01

Full Text Available El objetivo de este estudio fue describir el nivel de seguridad alimentaria percibida en los hogares de la ciudad de Santa Fe, Argenttina, en el año 2011. Se realizó un estudio descriptivo, de corte transversal, incluyendo 592 hogares que integran el Panel de Hogares del Observatorio Social de la Universidad Nacional del Litoral. Los hogares se caracterizaron sociodemográficamente, se los clasificó según el nivel de seguridad alimentaria, aplicando la Escala Latinoamericana y Caribeña de Seguridad Alimentaria y se determinó su asociación, mediante odds ratio y regresión logística, con factores sociodemográficos. Se halló que el 31,5% de los hogares santafesinos presenta inseguridad alimentaria, de los cuales el 21,7% es leve, el 7,4% moderada y el 2,4% severa, incrementándose cuando conviven menores. La inseguridad alimentaria se asoció positivamente con no poseer cobertura de salud, actividad económica, capacidad de ahorro ni el secundario completo y con la existencia de cuatro o más integrantes en el hogar.

Finance and faith at the Catholic Maternity Institute, Santa Fe, New Mexico, 1944-1969.

Science.gov (United States)

Cockerham, Anne Z; Keeling, Arlene W

2010-01-01

In 1944, the Medical Mission Sisters opened the Catholic Maternity Institute in Santa Fe, New Mexico, primarily to serve patients of Spanish American descent. The Maternity Institute offered nurse-midwifery care and functioned as a school to train nurse-midwifery students. Originally planned as a home birth service, the Catholic Maternity Institute soon evolved into a service in which patients chose whether to deliver in their own homes or in a small freestanding building called La Casita. In fact, despite their idealism about home birth and strong feelings that home birth was best, the sisters experienced significant ambivalence concerning La Casita. Births there met many of the institute's pragmatic needs for a larger number of student experiences, quick and safe transfers to a nearby hospital, and more efficient use of the midwives' time. Importantly, as the sisters realized that many of their patients preferred to deliver at La Casita, they came to see that this option permitted these impoverished patients an opportunity to exercise some choice. However, the choice of many patients to deliver at La Casita--which was significantly more expensive for the Maternity Institute than home birth--eventually led to the demise of the Maternity Institute.

Accreditation of the mammography's services in the city of Santa Fe

International Nuclear Information System (INIS)

Caspani, Carlos; Lescano, Roberto

2008-01-01

Full text: In Radiofisica of Santa Fe, like final work of the career of Bioengineering, a phantom developed with the purpose of being used in accreditation of mammography's services, where the inserted ones that simulate small fibbers, the nodules and the micro-calcifications arrange in random form, in such a way that the professional that reads the mammographic film does not know its distribution a priori. For that reason with a taking (with the best technique, than he determines the one that makes the practice, for a normal breast of 4.2 cm of compressed thickness), the informant it indicates what sees and in what place of the film is, and thus to obtain a number; this is complemented more with two actions, on the one hand a minimum evaluation of the service is made, (that registry takes of the made studies, that structured program of qualification they have, that percentage gives them control program of repetition of film, that control of the revealed make systematically and that control of quality of the equipment carries out). In order to complete this evaluation the capture of the phantom has a TLD's chip to be able to read in addition its dose to entrance in skin, that serves next to the record as the reading as the film as phantom and the fact to me to have implemented a minimum program of QC; to determine a priori and in very fast forms, if that audited service can credit or no, to join a program of pre-clinical detection of the mammary cancer. (author)

Microstructure and magnetic properties of nanocomposite FePt/MgO and FePt/Ag films

International Nuclear Information System (INIS)

Chen, S.C.; Kuo, P.C.; Sun, A.C.; Chou, C.Y.; Fang, Y.H.; Wu, T.H.

2006-01-01

An in-plane magnetic anisotropy of FePt film is obtained in the MgO 5 nm/FePt t nm/MgO 5 nm films (where t=5, 10 and 20 nm). Both the in-plane coercivity (H c- parallel ) and the perpendicular magnetic anisotropy of FePt films are increased when introducing an Ag-capped layer instead of MgO-capped layer. An in-plane coercivity is 3154 Oe for the MgO 5 nm/FePt 10 nm/MgO 5 nm film, and it can be increased to 4846 Oe as a 5 nm Ag-capped layer instead of MgO-capped layer. The transmission electron microscopy (TEM)-energy disperse spectrum (EDS) analysis shows that the Ag mainly distributed at the grain boundary of FePt, that leads the increase of the grain boundary energy, which will enhance coercivity and perpendicular magnetic anisotropy of FePt film

Tasa de infección en el sitio operatorio en cirugía de revascularización miocárdica en la Fundación Santa Fe de Bogotá

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Luis E. Silva, MD

2011-05-01

Conclusiones: la profilaxis usada para cirugía cardiovascular en la Fundación Santa Fe de Bogotá ha demostrado menor incidencia de infección del sitio operatorio tanto superficial como profundo, en comparación con la que recomiendan en las guías de la ACC/AHA, sin aumentar la incidencia de resistencia a los antibióticos usados.

Caracterización de los pacientes críticos ventilados en la Fundación Santa Fe de Bogotá 2009 a 2013

OpenAIRE

Gómez Cortés, Leonardo Andrés; Bernal Ramírez, Omar Javier

2013-01-01

Objetivo: Caracterizar a los pacientes que recibieron ventilación mecánica en las unidades de cuidado intensivo (UCI) de la Fundación Santa Fe de Bogotá entre los años 2009 y 2013. Metodología: Se analizó una cohorte retrospectiva de los pacientes en UCI que requirieron soporte ventilatorio mecánico al ingreso a la unidad independientemente de la causa. Resultados: La media de edad de los pacientes fue 63,83 años; el diagnóstico más frecuente de ingreso fue revascularización miocárdi...

Evaluación de la abundancia y diversidad de lombrices de tierra en relación con el uso del suelo en el cinturón hortícola de Santa Fe (Argentina Monitoring of earthworms populations in the cinturón hortícola Santa fe (Argentina

Directory of Open Access Journals (Sweden)

Carolina Elisabet Masín

2011-07-01

Full Text Available Las lombrices de tierra constituyen un componente importante en la fauna del suelo contribuyendo activa y beneficiosamente en su estructura y fertilidad. Estos organismos son sensibles ante distintos manejos y grados de perturbación del suelo respondiendo como bioindicadores de la «salud» del mismo. El Cinturón Hortícola Santafesino (Santa Fe, Argentina exhibe diferencias no sólo en tipos de cultivos sino también en sistemas de producción y condiciones de trabajo. El objetivo del estudio fue determinar la abundancia y diversidad de la oligoquetofauna en los suelos con distintos tipos de manejo en las localidades de Ángel Gallardo y Monte Vera (Dpto. La Capital, Santa Fe - Argentina. Se seleccionaron tres agroecosistemas: labranza convencional (LC, siembra directa orgánica (SDO y siembra directa (SD. En cada campo se realizaron dos muestreos, correspondiendo uno a la estación verano y el otro a otoño de 2008. Se analizaron algunas propiedades físicas y químicas de los suelos como también residuos de plaguicidas. La densidad de oligoquetos presentó diferencias por estación y sistemas de producción (p = 0,001 destacándose el sitio de SDO con el mayor número de individuos en las dos estaciones muestreadas. La taxocenosis constó de dos familias: Lumbricidae y Megascolecidae, y tres especies: Aporrectodea rosea, Aporrectodea trapezoides y Amynthas morrisi. La diversidad fue baja (H'= 0,33, siendo A. rosea la especie más común en los sitios muestreados y A. trapezoides la más abundante, incorporándose estaúltima a la lista de oligoquetos para la zona hortícola ya que en estudios anteriores no se hallaba registrada. La composición y estructura de la taxocenosis de lombrices de tierra se ve afectada no sólo por las condiciones ambientales y labores de producción, sino también por los parámetros físicos y químicos del suelo, que en conjunto condicionan la sensibilidad de la oligoquetofauna.Earthworms are an important

Gobierno provincial, empresarios y CGT frente a la apertura del juego corporativo durante el primer peronismo: Santa Fe, 1952-1955

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María Mercedes Prol

2010-04-01

Full Text Available Este artículo describe los conflictos suscitados durante el primer peronismo entre el Poder Ejecutivo de Santa Fe, la Federación Económica que agrupó a los empresarios del distrito y los diputados sindicales pertenecientes a la CGT a causa de la inclusión de la mencionada Federación en la gestión de gobierno. Tales conflictos se desarrollaron en un proceso de creciente corporativización de la política. Se reconstruyen brevemente dos movimientos paralelos que fomentaron dicha corporativización: la agremiación de los empresarios radicados en la provincia, quienes lograron conformar una central única; y la acción de los diputados sindicales dentro de la Cámara Legislativa provincial

Caracterización del régimen agroclimático de heladas para la provincia de Santa Fe durante el período 1979 - 2004

OpenAIRE

García, María Soledad; Leva, Perla E.; Valtorta, Silvia Elsa

2008-01-01

p.53-62 El conocimiento del régimen de las temperaturas consideradas limitantes para los cultivos, es indispensable para la toma de decisiones respecto al calendario agrícola de una región. Con datos de temperatura mínima diaria de seis localidades de la provincia de Santa Fe, donde existen estaciones del SMN (período 1979-2004) se caracterizó el régimen agroclimático de heladas meteorológicas y agronómicas. Se determinaron las fechas medias de primeras y últimas heladas, las respectivas f...

Sol-gel synthesis of 8 nm magnetite (Fe 3O 4) nanoparticles and their magnetic properties

KAUST Repository

Lemine, O. M.; Omri, Karim; Zhang, Bei; El Mir, Lassaad; Sajieddine, Mohammed; Alyamani, Ahmed Y.; Bououdina, M.

2012-01-01

Magnetite (Fe 3O 4) nanoparticles were successfully synthesized by a sol-gel method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDAX), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) and Mössbauer spectrometry. XRD and Mössbauer measurements indicate that the obtained nanoparticles are single phase. TEM analysis shows the presence of spherical nanoparticles with homogeneous size distribution of about 8 nm. Room temperature ferromagnetics behavior was confirmed by SQUID measurements. The mechanism of nanoparticles formation and the comparison with recent results are discussed. Finally, the synthesized nanoparticles present a potential candidate for hyperthermia application given their saturation magnetization. © 2012 Elsevier Ltd. All rights reserved.

Sol-gel synthesis of 8 nm magnetite (Fe 3O 4) nanoparticles and their magnetic properties

KAUST Repository

Lemine, O. M.

2012-10-01

Magnetite (Fe 3O 4) nanoparticles were successfully synthesized by a sol-gel method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDAX), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) and Mössbauer spectrometry. XRD and Mössbauer measurements indicate that the obtained nanoparticles are single phase. TEM analysis shows the presence of spherical nanoparticles with homogeneous size distribution of about 8 nm. Room temperature ferromagnetics behavior was confirmed by SQUID measurements. The mechanism of nanoparticles formation and the comparison with recent results are discussed. Finally, the synthesized nanoparticles present a potential candidate for hyperthermia application given their saturation magnetization. © 2012 Elsevier Ltd. All rights reserved.

Transportation of a 451 ton generator stator and a 234 ton generator rotor from Hartsville, TN, to Los Alamos, NM

International Nuclear Information System (INIS)

Boenig, H.J.; Rogers, J.D.; McLelland, G.R.; Pelts, C.T.

1989-01-01

A 1430 MVA steam turbine generator was acquired from a cancelled nuclear power plant in Tennessee to be used as the pulsed power and energy storage unit for the Confinement Physics Research Facility being built at Los Alamos, NM. The transportation from Hartsville, near Nashville, TN, to Los Alamos, NM, of the two largest single pieces of the generator, a 451 t stator and a 234 t rotor presented a special challenge. Details of the move, by barge from Hartsville to Catoosa, near Tulsa, OK, by rail from Catoosa to Lamy, near Santa Fe, NM, and by road from Lamy to Los Alamos are described. The greatest difficulty of the successful move was the crossing of the Rio Grande river on an existing reinforced concrete bridge. The two-lane wide road transporters for the stator and rotor were fitted with outriggers to provide a four-lane wide vehicle, thus spreading the load over the entire bridge width and meeting acceptable load distribution and bridge safety factors. 2 refs., 6 figs

Organic matter dynamics in a karstic watershed: Example from Santa Fe River, Florida, USA

Science.gov (United States)

Jin, J.; Khadka, M. B.; Martin, J. B.; Zimmerman, A. R.

2011-12-01

Organic matter (OM) dynamics in karstic watersheds can involve a range of interactions between organic and inorganic phases of carbon. These interactions include OM remineralization, which will changes its lability, increase dissolved inorganic carbon (DIC) concentrations, reduce pH, and enhance carbonate mineral dissolution. Dissolved organic carbon (DOC) concentrations are elevated in black-water rivers of northern Florida from both allochthonous and autochthonous sources and these rivers flow into and interact with the karstic Floridan Aquifer. One such river, the Santa Fe River, is split into upper confined and lower unconfined watersheds by the Cody Scarp, which represent the erosional edge of a regional confining unit. Water samples were collected from 8 sites across the entire Santa Fe River watershed (SFRW) during 9 sampling trips from December 2009 to May 2011 at flow conditions that ranged from 27 to 39 m3/s, with the highest flow about 45% higher than baseflow. At sites above the Cody Scarp, the river has elevated DOC concentrations, which decrease downstream, while dissolved inorganic carbon (DIC) and δ13C-DIC show opposite trends. At high flow, DOC concentrations progressively decrease downstream from dilution by low-DOC water discharging from the Floridan Aquifer. At low flow, the water chemistry varies little from upstream to downstream, largely because the composition of upstream water becomes similar to that of downstream water. DOC is inversely and linearly correlated with DIC and δ13C-DIC, but the slope of the correlations vary with discharge, with low flow having more negative slopes than high flow. The OM becomes more labile with distance downstream as assessed using two fluorescence indices, biological/autochthonous index (BIX) and humification index (HIX). This increase in lability suggests that DOC is produced in the river, and this production is reflected in a downstream increase in DOC flux regardless of dilution by the influx of low

Modification of interlayer exchange coupling in Fe/V/Fe trilayers using hydrogen

Energy Technology Data Exchange (ETDEWEB)

Skoryna, J., E-mail: jskoryna@ifmpan.poznan.pl [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland); Marczyńska, A. [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland); Lewandowski, M. [NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85 St., 61-614 Poznań (Poland); Smardz, L. [Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17 St., 60-179 Poznań (Poland)

2015-10-05

Highlights: • Magnetic films and multilayers. • Thin films. • Hydrogen absorbing materials. • Magnetic measurements. • Exchange coupling. - Abstract: Fe/V/Fe trilayers with constant-thickness Fe and step-like wedged V sublayers were prepared at room temperature using UHV magnetron sputtering. The bottom Fe layer grows onto oxidised Si(1 0 0) substrate and shows relatively high coercivity. The top Fe layer grows on vanadium spacer and shows considerably lower coercivity. The planar growth of the Fe and V sublayers was confirmed in-situ by X-ray photoelectron spectroscopy. Results show that the Fe sublayers are weakly exchange coupled for d{sub V} > 1.4 nm. Results on the coercivity studies as a function of the V interlayer thickness show near d{sub V} ∼ 1.95 nm (∼2.45 nm) weak antiferromagnetic (ferromagnetic) coupling, respectively. The hydrogenation of the Fe/V/Fe trilayers leads to increase of the strength of the ferromagnetic interlayer exchange coupling.

DCS Hydrology Submittal, Santa Fe County, NM and Incorporated Areas

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — Hydrology data include spatial datasets and data tables necessary for documenting the hydrologic procedures for estimating flood discharges for a flood insurance...

Propiedades fisicoquímicas en suelos predominantes del noroeste de Santa Fe y sur de Santiago del Estero, Argentina Physicochemical properties of predominant soils in Northwestern Santa Fe and Southern Santiago del Espero provinces, Argentina

Directory of Open Access Journals (Sweden)

Germán Roberto Revelli

2010-12-01

Full Text Available Un total de 175 muestras de suelos fueron recolectadas en la zona noroeste de Santa Fe y sur de Santiago del Estero durante el período 2001-2009. Se realizaron análisis fisicoquímicos (pH, Nitrógeno Total, Nitrógeno Nítrico, Nitrato, Fósforo, Potasio, Azufre y Materia Orgánica con el objetivo de categorizar las mismas en función a su calidad y aptitud para uso agrícola-ganadero. El perfil de los suelos analizados destaca deficiencias en Nitrógeno (NT = 0,127 ± 0,032%, N-NO3-= 13 ± 10,349 mg kg-1 y NO3- = 56 ± 45,830 mg kg-1 y un potencial de hidrógeno levemente ácido (pH = 6,4 ± 0,623, observándose una marcada tendencia a aumentar la acidificación en los últimos años. La fertilización equilibrada adquiere importancia estratégica a la hora de obtener óptimos rendimientos en los suelos de la zona, y la incorporación de prácticas de manejo conservadoras tales como labranza reducida, aumento de materia orgánica y rotación de cultivos son fundamentales para el desarrollo sostenible de la región.In recent years, there has been an increasing interest in evaluating soil quality and health. The resource soil is a fundamental component of the biosphere, participating in the production of food, fibers and energy and consequently impacting on the environmental quality. The indiscriminate expansion of agriculture added to the inadequate management in many areas has led to the deterioration of soil structure and to the consequent reduction in organic matter levels, affecting the soil chemical and physical fertility. A total of 175 soil samples were collected in the northwestern area of Santa Fe and in the southern part of Santiago del Estero provinces during the 2001-2009 period. Physicochemical analyses were carried out (pH, Total Nitrogen, Nitrate- Nitrogen, Nitrate, Phosphorus, Potassium, Sulfur and Organic Matter with the objective of categorizing the soil samples according to fertility and aptitude for agricultural-cattle use

Análisis espacial de los accidentes laborales in itinere en veterinarios de grandes animales en la provincia de Santa Fe

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Ana Inés Molineri

2016-12-01

Full Text Available En la práctica de grandes animales el profesional debe viajar frecuentemente para atender a sus clientes, exponiéndose a los riesgos del tránsito. Los objetivos de este trabajo fueron: a evaluar la frecuencia de veterinarios que sufrieron accidentes laborales in itinere (Alii en la provincia de Santa Fe y la posible asociación espacial entre los casos detectados y b estimar la percepción de los riesgos y el uso de elementos de protección personal. Se efectuó un estudio observacional sobre profesionales veterinarios que se dedican al manejo y atención de grandes animales en la provincia de Santa Fe, Argentina. El diseño fue transversal, la unidad de interés el veterinario y la población objetivo los veterinarios rurales santafesinos. La tasa de respuesta a un cuestionario estructurado que respondieron en forma anónima fue del 75,8 % (n= 562. El análisis de los datos incluyó la búsqueda de agrupamientos espaciales para poblaciones de distribución heterogénea utilizando el programa SatScan versión 9.2. La frecuencia de accidentes fue del 14,8 %. Se encontró un agrupamiento espacial (p= 0,017 en el sudeste provincial (riesgo relativo= 0,42. La frecuencia de veterinarios que sufrieron accidentes fue decreciendo desde el norte al sur de la provincia. El tránsito en rutas fue percibido como más riesgoso por una mayor proporción de entrevistados que el tránsito en caminos rurales. Las frecuencias de uso de luz baja durante el día y cinturón de seguridad fueron independientes de las percepciones del riesgo en el tránsito. Dado que la frecuencia de accidentes entre los veterinarios es alta, resulta fundamental diseñar estrategias de educación para evitar daños futuros.

La mortalidad infantil en Santa Fe, Argentina (2007-2011. Un aporte al monitoreo de los derechos de los niños

Directory of Open Access Journals (Sweden)

Ana Cecilia Augsburger

2015-07-01

Full Text Available La mortalidad infantil en Santa Fe tuvo un comportamiento similar al de Argentina, acompañando el descenso que se presentó para el país, aunque siempre con valores inferiores al indicador nacional. Pese a ello, mereció particular preocupación la elevada proporción de defunciones cuyas causas se consideran reducibles con valores históricos superiores al 50%. El establecimiento de las metas internacionales conocidas como Objetivos de Desarrollo del Milenio, que bregó por la protección de los derechos de la niñez, contó con la ratificación nacional al tiempo que la provincia se comprometió con estos fijándolos como política socio-sanitaria estratégica. El estudio construyó el perfil de la mortalidad infantil de la provincia de Santa Fe durante el quinquenio 2007-2011. Se realizó un estudio epidemiológico descriptivo y transversal. La población incluyó las defunciones en menores de un año del período estudiado. Se analizó su distribución según la edad al morir, peso al nacer y lugar de ocurrencia, causas de muerte y criterios de reducibilidad. Ocurrieron 2.904 muertes de niños, obteniendo una tasa del 10,9‰, que mantuvo el comportamiento descendente previo. Las muertes neonatales duplicaron la mortalidad posneonatal y se concentraron en la primera semana de vida. Las causas más frecuentes estuvieron asociadas a los problemas perinatales. El mayor riesgo de morir fue para los niños de menos de 1.000 gramos o inmadurez extrema. El 60% de los eventos podría haberse evitado. La persistencia de muertes consideradas reducibles debería estimular para incentivar estrategias de intervenciones sociales y sanitarias más equitativas y de protección de la infancia.

La mortalidad infantil en Santa Fe, Argentina (2007-2011. Un aporte al monitoreo de los derechos de los niños

Directory of Open Access Journals (Sweden)

Ana Cecilia Augsburger

2015-01-01

Full Text Available La mortalidad infantil en Santa Fe tuvo un comportamiento similar al de Argentina, acompañando el descenso que se presentó para el país, aunque siempre con valores inferiores al indicador nacional. Pese a ello, mereció particular preocupación la elevada proporción de defunciones cuyas causas se consideran reducibles con valores históricos superiores al 50%. El establecimiento de las metas internacionales conocidas como Objetivos de Desarrollo del Milenio, que bregó por la protección de los derechos de la niñez, contó con la ratificación nacional al tiempo que la provincia se comprometió con estos fijándolos como política socio-sanitaria estratégica. El estudio construyó el perfil de la mortalidad infantil de la provincia de Santa Fe durante el quinquenio 2007-2011. Se realizó un estudio epidemiológico descriptivo y transversal. La población incluyó las defunciones en menores de un año del período estudiado. Se analizó su distribución según la edad al morir, peso al nacer y lugar de ocurrencia, causas de muerte y criterios de reducibilidad. Ocurrieron 2.904 muertes de niños, obteniendo una tasa del 10,9‰, que mantuvo el comportamiento descendente previo. Las muertes neonatales duplicaron la mortalidad posneonatal y se concentraron en la primera semana de vida. Las causas más frecuentes estuvieron asociadas a los problemas perinatales. El mayor riesgo de morir fue para los niños de menos de 1.000 gramos o inmadurez extrema. El 60% de los eventos podría haberse evitado. La persistencia de muertes consideradas reducibles debería estimular para incentivar estrategias de intervenciones sociales y sanitarias más equitativas y de protección de la infancia.

Holocene soft-sediment deformation of the Santa Fe-Sopetrán Basin, northern Colombian Andes: Evidence for pre-Hispanic seismic activity?

Science.gov (United States)

Suter, F.; Martínez, J. I.; Vélez, M. I.

2011-04-01

The detailed study of four deformed intervals from the Holocene fluvio-lacustrine deposits of the Santa Fe-Sopetrán Basin in northern Colombia shows 17 types of soft-sediment deformation (SSD) structures. Evidence indicates that seismic activity was responsible for the SSD structures, a conclusion reached after considering the environmental conditions at the time of sediment deposition and shortly after, and the detailed analysis of the driving force systems. Other triggers (i.e. overloading and rapid sedimentation), however, are not discarded. Intervals showing SSD structures occurred at centennial frequencies and apparently resulted from Mw 6-7 earthquakes. The Holocene age of these major shaking events should be seriously considered when evaluating the seismic hazard and risk for the middle Cauca Valley and the nearby city of Medellín with 3 million inhabitants.

Saturated and trans fatty acids content in unpackaged traditional bakery products in Santa Fe city, Argentina: nutrition labeling relevance.

Science.gov (United States)

Negro, Emilse; González, Marcela Aída; Bernal, Claudio Adrián; Williner, María Rosa

2017-08-01

Studies have reported the relationship between the excessive intake of saturated fatty acids (SFA) and trans fatty acids (t-FA) and an increased risk of cardiovascular disease. Since 2006, the MERCOSUR countries require that the mandatory nutrition labeling should include information not only about the content of SFA but also about the content of t-FA. This does not apply to fractionated products at the point of retail, such as bakery products. This paper aimed to determine the total fat content and the fatty acid profile in unpackaged traditional bakery products (breads, biscuits and pastries) in Santa Fe, Argentina. Except for French bread, the contribution of t-FA and SFA to the total FA consumption from baked products was high. On the other hand, due to the high variability detected in the FA composition of bakery products between bakeries, it would be necessary to implement regulations making nutrition labeling mandatory in these products.

Exchange-coupled Fe3O4/CoFe2O4 nanoparticles for advanced magnetic hyperthermia

Science.gov (United States)

Glassell, M.; Robles, J.; Das, R.; Phan, M. H.; Srikanth, H.

Iron oxide nanoparticles especially Fe3O4, γ-Fe2O3 have been extensively studied for magnetic hyperthermia because of their tunable magnetic properties and stable suspension in superparamagnetic regime. However, their relatively low heating capacity hindered practical application. Recently, a large improvement in heating efficiency has been reported in exchange-coupled nanoparticles with exchange coupling between soft and hard magnetic phases. Here, we systematically studied the effect of core and shell size on the heating efficiency of the Fe3O4/CoFe2O4 core/shell nanoparticles. The nanoparticles were synthesized using thermal decomposition of organometallic precursors. Transmission electron microscopy (TEM) showed formation of spherical shaped Fe3O4 and Fe3O-/CoFe2O4 nanoparticles. Magnetic measurements showed high magnetization (≅70 emu/g) and superparamagnetic behavior for the nanoparticles at room temperature. Magnetic hyperthermia results showed a large increase in specific absorption rate (SAR) for 8nm Fe3O4/CoFe2O4 compared to Fe3O4 nanoparticles of the same size. The heating efficiency of the Fe3O4/CoFe2O4 with 1 nm CoFe2O4 (shell) increased from 207 to 220 W/g (for 800 Oe) with increase in core size from 6 to 8 nm. The heating efficiency of the Fe3O4/CoFe2O4 with 2 nm CoFe2O4 (shell) and core size of 8 nm increased from 220 to 460 W/g (for 800 Oe). These exchange-coupled Fe3O4/CoFe2O4 core/shell nanoparticles can be a good candidate for advanced hyperthermia application.

Determinación de la rugosidad superficial y anchos de inundación en la planicie del río Salado (Santa Fe) para la crecida de 2003

OpenAIRE

Imhoff, Matías; Trento, Alfredo

2012-01-01

Las planicies de inundación en ríos de llanura cumplen un papel fundamental en las crecidas, puesto que almacenan y conducen una parte importante del caudal, de lo cual se deriva la importancia de la correcta representación de la rugosidad superficial en las modelaciones hidrodinámicas. La zona de estudio corresponde al tramo del río Salado (Santa Fe, Argentina) comprendido entre la confluencia con el Arroyo Cululú y la ruta provincial N° 70. El objetivo fue determinar la rugosidad superficia...

Workshop on geologic data requirements for radioactive waste management assessment models, Santa Fe, New Mexico, June 28--July 1, 1976

International Nuclear Information System (INIS)

1976-09-01

Exchange of information is needed among persons working in two broad categories of studies concerned with terminal storage of radioactive waste. These two categories are: (1) investigations of several types of geologic formations in a number of locations to determine suitability for use with various emplacement techniques, and (2) development of models for the ERDA, NRC, and EPA, for the general purpose of assessing the long term safety of terminal storage facilities. The Workshop held in Santa Fe, New Mexico, June 28-July 1, 1976, sponsored by the Office of Waste Isolation and arranged by The University of New Mexico addressed this need. Presentations covered background topics of: geologic studies being made, methods for risk analysis, assessment models being developed, and descriptions of field observations of radionuclide migration. During vigorous discussion periods, a list of items to be jointly attacked by geologists and modelers was worked out

Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

Energy Technology Data Exchange (ETDEWEB)

Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

2016-03-15

Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

Exchange biased FeNi/FeMn bilayers with coercivity and switching field enhanced by FeMn surface oxidation

Directory of Open Access Journals (Sweden)

A. V. Svalov

2013-09-01

Full Text Available FeNi/FeMn bilayers were grown in a magnetic field and subjected to heat treatments at temperatures of 50 to 350 °C in vacuum or in a gas mixture containing oxygen. In the as-deposited state, the hysteresis loop of 30 nm FeNi layer was shifted. Low temperature annealing leads to a decrease of the exchange bias field. Heat treatments at higher temperatures in gas mixture result in partial oxidation of 20 nm thick FeMn layer leading to a nonlinear dependence of coercivity and a switching field of FeNi layer on annealing temperature. The maximum of coercivity and switching field were observed after annealing at 300 °C.

Clarifying roughness and atomic diffusion contributions to the interface broadening in exchange-biased NiFe/FeMn/NiFe heterostructures

Energy Technology Data Exchange (ETDEWEB)

Nascimento, V.P., E-mail: valberpn@yahoo.com.br [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Merino, I.L.C.; Passamani, E.C. [Departamento de Física, Universidade Federal do Espírito Santo, 29075-910 Vitória (Brazil); Alayo, W. [Departamento de Física, Universidade de Pelotas, 96010-610 Pelotas (Brazil); Tafur, M. [Instituto de Ciências Exatas, Universidade Federal de Itajubá, 37500-903 Itajubá (Brazil); Pelegrini, F. [Instituto de Física, Universidade Federal de Goiás, 74001-970 Goiânia (Brazil); Magalhães-Paniago, R. [Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Alvarenga, A.D. [Instituto Nacional de Metrologia, 25250-020 Xerém (Brazil); Saitovitch, E.B. [Coordenação de Física Experimental e Baixas Energias, Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro (Brazil)

2013-09-02

NiFe(30 nm)/FeMn(13 nm)/NiFe(10 nm) heterostructures prepared by magnetron sputtering at different argon working pressures (0.27, 0.67 and 1.33 Pa) were systematically investigated by using specular and off-specular diffuse X-ray scattering experiments, combined with ferromagnetic resonance technique, in order to distinguish the contribution from roughness and atomic diffusion to the total structural disorder at NiFe/FeMn interfaces. It was shown that an increase in the working gas pressure from 0.27 to 1.33 Pa causes an enhancement of the atomic diffusion at the NiFe/FeMn interfaces, an effect more pronounced at the top FeMn/NiFe interface. In particular, this atomic diffusion provokes a formation of non-uniform magnetic dead-layers at the NiFe/FeMn interfaces (NiFeMn regions with paramagnetic or weak antiferromagnetic properties); that are responsible for the substantial reduction of the exchange bias field in the NiFe/FeMn system. Thus, this work generically helps to understand the discrepancies found in the literature regarding the influence of the interface broadening on the exchange bias properties (e.g., exchange bias field) of the NiFe/FeMn system. - Highlights: • Roughness and atomic diffusion contributions to the interface broadening • Clarification of the exchange bias field dependence on the interface disorder • Ferromagnetic, paramagnetic and antiferromagnetic phases at the magnetic interface • Magnetic dead layers formed by increasing the argon work pressure • Atomic diffusion in heterostructures prepared at higher argon pressure.

[Diversity of birds in the Agricultural Center Cotové, Santa Fe de Antioquia, Colombia].

Science.gov (United States)

Martínez-Bravo, Caty Milena; Mancera-Rodríguez, Néstor Javier; Buitrago-Franco, Germán

2013-12-01

Fragmentation of natural habitats is a central concern of biodiversity conservation and is considered a significant factor contributing to species loss and populations decline. We studied this in Cotové Agricultural Center in the municipality of Santa Fe de Antioquia (Colombia),where the conversion of natural forests to different land use systems, has limited the amount of available habitat. With the aim to describe the effect of habitat loss on bird presence in five land uses (fruiting trees, silvopastoral systems, secondary forest, pasture low density of trees and grass cutting) in this area, we studied bird diversity using two methods: fixed point counts and mist nets to analyze the influence of land use in the composition, richness and abundance of birds present were studied. A total of 6633 individuals of 101 species were observed of which 11 species were migratory. The insectivorous and frugivorous foraging guilds were better represented. The Shannon index indicated the highest values of alpha diversity for the silvopastoral system, and the fruit with the lowest. The grazing and silvopastoral land systems shared more species with low tree density. The importance of the environmental heterogeneity found is highlighted as a positive factor for bird species richness, mostly of low and middle habitat specificity, and preferably from edge habitats and open areas. In order to preserve natural regeneration and connectivity between different land use types, and to promote stability of bird species populations, some management actions should be implemented in the area.

Descripción de un brote de leptospirosis en la ciudad de Santa Fe, Argentina, marzo-abril de 1998 Description of a leptospirosis outbreak in the city of Santa Fe, Argentina, March-April 1998

Directory of Open Access Journals (Sweden)

Norma B. Vanasco

2000-01-01

Full Text Available En marzo-abril de 1998 se identificó en un barrio de la ciudad de Santa Fe (Argentina un brote de una enfermedad aguda caracterizada por fiebre, cefaleas y mialgias intensas. Se presentan los estudios realizados en relación con este brote y los intentos de identificación de la fuente y del modo de transmisión. Los hallazgos epidemiológicos, serológicos y clínicos indicaron que el agente causal fue Leptospira interrogans. Como prueba de tamizaje se aplicó la técnica de aglutinación macroscópica con antígeno termorresistente, seguida de la prueba de ELISA y, como prueba de confirmación, la aglutinación microscópica frente a 10 serovariedades de L. interrogans. Se estudiaron 32 individuos, 8 perros y 8 muestras de agua. Se registraron 12 casos confirmados, 2 probables y 18 negativos. En seis perros se demostró la existencia de infección y en las muestras de agua se detectó la presencia de espiroquetas móviles. Los sueros humanos reaccionaron con las serovariedades ballum, canicola, icterohaemorrhagiae y pyrogenes, y los caninos con ballum, canicola y pomona. La coaglutinación observada en todos los casos confirmados indica que se trató de casos agudos de leptospirosis, pero no permite identificar la serovariedad causal. Salvo en el caso índice, no se reconoció clínicamente la enfermedad. Varios hechos sugieren que la causa del brote fue la inundación pluvial de la zona estudiada. Los resultados de este estudio resaltan la necesidad de una vigilancia activa de la leptospirosis ante desastres naturales como las inundaciones.In March-April 1998 in a neighborhood in the city of Santa Fe, Argentina, there was an outbreak of an acute disease characterized by fever, headaches, and intense myalgias. This article presents the studies surrounding this outbreak and the attempts to identify the source and the mode of transmission. The epidemiological, serological, and clinical findings indicated that the causative agent was Leptospira

Considerations on the feasibility of using wind energy for electricity generation in the regional areas of the Province of Santa Fe, Argentina; Consideraciones sobre la viabilidad del uso de energia eolica para la generacion de electricidad en el ambito regional de la Provincia de Santa Fe

Energy Technology Data Exchange (ETDEWEB)

Gibbons, Roberto E.; Nachez, Antonio E. [Universidad Nacional de Rosario (Argentina). Fac. de Ciencias Exactas, Ingenieria y Agrimensura. Dept. de Electronica], Emails: rgibbons@eie.fceia.unr.edu.ar, anachez@eie.fceia.unr.edu.ar

2009-07-01

This article presents the current status of the use of wind power and evaluating the factors that affecting the implementation in the generation of electricity. From information available on the winds in four cities in the Santa Fe Province, calculate the potential of generation to determine the feasibility of using energy wind as an alternative source of energy in the province. The information was provided by the Ministry of Defence, Ministry of Planning, National Weather Service Meteorological Information Center and consists of a total of 8462 measurements of wind speed and direction in hourly intervals during each day of the year 2007, in weather stations located in the towns of Ceres, Rosario, Reconquista and Sauce Viejo. Using data collected by weather stations in the expressions for the calculation of available power in the wind, it is shown that the study areas are not suitable for utilization of wind energy.

Cumplimiento de las recomendaciones de prevención secundaria de enfermedad coronaria en pacientes sometidos a revascularización coronaria percutánea en el Hospital Universitario Fundación Santa Fe de Bogotá

Directory of Open Access Journals (Sweden)

César J Villalobos

2013-04-01

Full Text Available Marco de referencia: diferentes ensayos clínicos han mostrado que el efecto de las revascularizaciones y los procedimientos de angioplastia en el pronóstico del paciente, tiene sólo un efecto a corto plazo, mientras que la prevención secundaria (cambio de estilo de vida y tratamiento intensivo mejora el pronóstico a largo plazo. Objetivo: evaluar el cumplimiento de las recomendaciones para prevención cardiovascular secundaria, de los pacientes sometidos a revascularización coronaria percutánea en el hospital universitario Fundación Santa Fe de Bogotá, entre los anos 2008 y 2010. Materiales y métodos: estudio descriptivo, ambispectivo, cuya población estuvo conformada por 332 pacientes sometidos a intervención coronaria percutánea atendidos entre enero de 2008 a diciembre de 2010 en el servicio de hemodinamia del Hospital Universitario Fundación Santa Fe de Bogotá. La recolección de la información se realizó mediante revisión de las historias clínicas de los pacientes y vía telefónica. Las metas de control se basaron en las recomendaciones de la Asociación Americana del Corazón y el Colegio Americano de Cardiología. Resultados: 332 pacientes fueron sometidos a revascularización coronaria percutánea y 4 fueron excluidos del estudio por falta de datos. La presentación clínica más frecuente fue la angina inestable (32,93%. Sólo se contactaron 172 (52,43% pacientes, de los cuales 77,4% eran hombres y 22,6% mujeres. Únicamente 6 (3,5% cumplían con el 100% de las recomendaciones para la prevención secundaria de enfermedad coronaria y 17% cumplía menos del 50% de éstas. Conclusiones: la experiencia en la Fundación Santa Fe de Bogotá muestra un pobre cumplimiento de las metas de prevención secundaria de enfermedad coronaria.

La cocina del trabajo periodístico. Desigualdades de género y distribución de poder en las redacciones informativas de la provincia de Santa Fe

Directory of Open Access Journals (Sweden)

Florencia Laura Rovetto

2015-12-01

Full Text Available En este trabajo abordamos las condiciones de producción de los mensajes periodísticos y las prácticas laborales teniendo en cuenta la distribución de poder y su articulación con los condicionantes de género en los medios informativos de la provincia de Santa Fe en un contexto determinado por planes y normativas provinciales y nacionales destinadas a fomentar el acceso y la participación de las mujeres en la producción de contenidos mediáticos. Para ello, en primer lugar, revisamos los antecedentes sobre la temática y su grado de desarrollo en el país con el fin de analizar las posibilidades que brindan para abordar este campo problemático en la actualidad. En segundo lugar, presentamos los resultados obtenidos a partir de la realización de una encuesta destinada a relevar el perfil de los profesionales que trabajan en los medios informativos de las principales ciudades de la provincia, así como sus percepciones en torno a desigualdades de género en las organizaciones y rutinas periodísticas. Hemos podido constatar que la participación diferenciada de varones y mujeres en las "cocinas" informativas de la provincia de Santa Fe pone en evidencia la persistencia de una "cultura periodística" masculina que lejos está de aproximarse a los principios emanados de las legislaciones sobre la igualdad de oportunidades y acceso equilibrado del conjunto de profesionales en las organizaciones mediáticas.

Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

Energy Technology Data Exchange (ETDEWEB)

Spizzo, F., E-mail: spizzo@fe.infn.it [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia and CNISM, Università di Perugia, I-06123 Perugia (Italy); Chinni, F.; Bonfiglioli, E. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy); Gerardino, A. [Istituto di Fotonica e Nanotecnologie, CNR, I-00156 Roma (Italy); Barucca, G. [Dipartimento SIMAU, Università Politecnica delle Marche, I-60131 Ancona (Italy); Bisero, D.; Fin, S.; Del Bianco, L. [Dipartimento di Fisica e Scienze della Terra and CNISM, Università di Ferrara, I-44122 Ferrara (Italy)

2016-02-15

We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm{sup 2}) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H{sub EX} measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H{sub EX} and of the coercivity H{sub C} are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H{sub EX}~90 Oe and H{sub C}~180 Oe in the dots and H{sub EX}~1270 Oe and H{sub C}~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K �

Exchange bias properties of 140 nm-sized dipolarly interacting circular dots with ultrafine IrMn and NiFe layers

International Nuclear Information System (INIS)

Spizzo, F.; Tamisari, M.; Chinni, F.; Bonfiglioli, E.; Gerardino, A.; Barucca, G.; Bisero, D.; Fin, S.; Del Bianco, L.

2016-01-01

We studied the exchange bias effect in an array of IrMn(3 nm)/NiFe(3 nm) circular dots (size ~140 nm and center-to-center distance ~200 nm, as revealed by microscopy analyses), prepared on a large area (3×3 mm"2) by electron beam lithography and lift-off, using dc sputtering deposition. Hysteresis loops were measured by SQUID magnetometer at increasing values of temperature T (in the 5–300 K range) after cooling from 300 K down to 5 K in zero field (ZFC mode) and in a saturating magnetic field (FC mode). The exchange bias effect disappears above T~200 K and, at each temperature, the exchange field H_E_X measured in ZFC is substantially lower than the FC one. Micromagnetic calculations indicate that, at room temperature, each dot is in high-remanence ground state, but magnetic dipolar interactions establish a low-remanence configuration of the array as a whole. Hence, at low temperature, following the ZFC procedure, the exchange anisotropy in the dot array is averaged out, tending to zero. However, even the FC values of H_E_X and of the coercivity H_C are definitely smaller compared to those measured in a reference continuous film with the same stack configuration (at T=5 K, H_E_X~90 Oe and H_C~180 Oe in the dots and H_E_X~1270 Oe and H_C~860 Oe in the film). Our explanation is based on the proven glassy magnetic nature of the ultrathin IrMn layer, implying the existence of magnetic correlations among the spins, culminating in a collective freezing below T~100 K. We propose, also by the light of micromagnetic simulations, that the small dot size imposes a spatial constraint on the magnetic correlation length among the IrMn spins so that, even at the lowest temperature, their thermal stability, especially at the dot border, is compromised. - Highlights: • Exchange bias in 140 nm-sized IrMn(3 nm)/NiFe(3 nm) dots much weaker than in a film. • Glassy magnetic nature of the IrMn phase and collective spin freezing at T<100 K • Confinement of IrMn magnetic

Violencia física contra la mujer en Santa Fe de Bogotá: prevalencia y factores asociados

Directory of Open Access Journals (Sweden)

Klevens Joanne

2001-01-01

Full Text Available Objetivos. Estimar la magnitud del problema de la violencia conyugal que afecta a las mujeres que acuden a los servicios de salud pública en Santa Fe de Bogotá, Colombia, e identificar los factores asociados con el riesgo de ser agredidas físicamente. Métodos. Se analizaron los datos recolectados desde septiembre de 1998 hasta septiembre de 1999 mediante entrevistas de las 3 971 mujeres con niños menores de 6 meses de edad, que solicitaron consulta por diversas causas pediátricas (control del niño sano, vacunación o morbilidad del menor o fueron atendidas por parto en la red de servicios de salud pública en la localidad de Suba, Santa Fe de Bogotá, Colombia. De la muestra indicada, 10 mujeres rehusaron participar y 804 no tenían compañero, por lo cual se excluyeron de los análisis. Resultados. De las 3 157 participantes que convivían con un compañero íntimo, 26,5% informaron que habían sido abofeteadas o empujadas por su compañero actual y 13,3% que habían sido agredidas gravemente por medio de golpes con el puño cerrado, patadas, golpes con algún objeto, "golpizas" y amenazas con un cuchillo o arma de fuego. Además de lo anterior, 26,2% de ellas indicaron que su compañero les imponía alguna prohibición. En los análisis bivariados, la violencia se asoció significativamente con menos escolaridad y menores ingresos (P < 0,001, mayor número de hijos (P < 0,001, mayor tiempo de unión con el compañero actual (P < 0,001, mayor frecuencia de conflicto con la pareja (P < 0,001, ausencia de otros familiares en el hogar (P < 0,01, historia de maltrato en la familia de origen (P < 0,001 y prohibiciones por parte del compañero (P < 0,001. La frecuencia del conflicto con la pareja y las prohibiciones fueron los factores más fuertemente asociados con la violencia, según el análisis multivariado. Conclusiones. Los servicios de salud pública son un buen lugar para detectar a las víctimas de la violencia intrafamiliar. Deben

Thick CoFeB with perpendicular magnetic anisotropy in CoFeB-MgO based magnetic tunnel junction

Directory of Open Access Journals (Sweden)

V. B. Naik

2012-12-01

Full Text Available We have investigated the effect of an ultra-thin Ta insertion in the CoFeB (CoFeB/Ta/CoFeB free layer (FL on magnetic and tunneling magnetoresistance (TMR properties of a CoFeB-MgO system with perpendicular magnetic anisotropy (PMA. It is found that the critical thickness (tc to sustain PMA is doubled (tc = 2.6 nm in Ta-inserted CoFeB FL as compared to single CoFeB layer (tc = 1.3 nm. While the effective magnetic anisotropy is found to increase with Ta insertion, the saturation magnetization showed a slight reduction. As the CoFeB thickness increasing, the thermal stability of Ta inserted structure is significantly increased by a factor of 2.5 for total CoFeB thickness less than 2 nm. We have observed a reasonable value of TMR for a much thicker CoFeB FL (thickness = 2-2.6 nm with Ta insertion, and without significant increment in resistance-area product. Our results reveal that an ultra-thin Ta insertion in CoFeB might pay the way towards developing the high-density memory devices with enhanced thermal stability.

Reduction under hydrogen of ferrite MFe{sub 2}O{sub 4} (M: Fe, Co, Ni) nanoparticles obtained by hydrolysis in polyol medium: A novel route to elaborate CoFe{sub 2}, Fe and Ni{sub 3}Fe nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ballot, N.; Schoenstein, F.; Mercone, S.; Chauveau, T.; Brinza, O. [Laboratoire des Sciences des Procedes et des Materiaux, CNRS, LSPM - UPR 3407, Universite Paris 13, PRES Sorbonne-Paris-Cite, 99 Avenue J.-B. Clement, 93430 Villetaneuse (France); Jouini, N., E-mail: jouini@univ-paris13.fr [Laboratoire des Sciences des Procedes et des Materiaux, CNRS, LSPM - UPR 3407, Universite Paris 13, PRES Sorbonne-Paris-Cite, 99 Avenue J.-B. Clement, 93430 Villetaneuse (France)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Spinels nano-particles MFe{sub 2}O{sub 4} (M: Co, Fe or Ni) are obtained by hydrolysis in polyol medium. Black-Right-Pointing-Pointer Gentle reduction under hydrogen flow of spinel nano-particles yields metal and alloy nanoparticles. Black-Right-Pointing-Pointer TEM and X-ray analysis show that CoFe{sub 2}, Fe and Ni{sub 3}Fe nano-particles are monocrystalline particles with size less than 160 nm. Black-Right-Pointing-Pointer Iron with size of 150 nm presents ferromagnetic behavior. Black-Right-Pointing-Pointer CoFe{sub 2} alloy with size of 55 nm could be considered as a superparamagnetic material. - Abstract: A novel method to process metal and various alloy particles of nanometric size is described. The first step consists in the elaboration of MFe{sub 2}O{sub 4} (M: Fe, Ni or Co) spinel nanoparticles in polyol medium via hydrolysis and the second one in gently reducing these latter under hydrogen at 300 Degree-Sign C. X-ray diffraction analysis shows that pure Fe and CoFe{sub 2} alloy are well obtained by reducing Fe{sub 3}O{sub 4} and CoFe{sub 2}O{sub 4}, respectively. This is not the case when we try to reduce NiFe{sub 2}O{sub 4}. A mixture of Fe and Ni{sub 3}Fe is observed. TEM analysis reveals that the size of metal particles stays within the range of a few tenths of nm up to 150 nm, while the precursors (MFe{sub 2}O{sub 4}) never exceed 5 nm. Our results show that the formation of metal particles occurs via two main steps: (i) reduction of the spinel oxide nanoparticles into metal ones and (ii) aggregation of the latter, leading to larger metal nanoparticles. Magnetic measurements indicate that the as-obtained metallic materials have good magnetic properties mainly affected by the sizes of the nanoparticles and the purity of the reduced phases.

Los derechos de propiedad en la frontera de Córdoba, Santa Fe y Buenos Aires a fines del siglo XIX

Directory of Open Access Journals (Sweden)

Tognetti, Luis Alberto

2010-01-01

Full Text Available En este trabajo analizamos la instauración de los derechos de propiedad sobre las tierras incorporadas por el avance de la frontera de 1869 en un espacio de contacto entre tres jurisdicciones provinciales. Con el objetivo de indagar cómo se resolvió la superposición de los intereses territoriales de Córdoba, Buenos Aires y Santa Fe, seguiremos la estrategia desarrollada por la primera de esas jurisdicciones, que definimos como una transacción incompleta. La perspectiva propuesta constituye un abordaje diferente respecto a la problemática del acceso a la propiedad en la frontera, que toma en cuenta el cambio institucional que significó el fortalecimiento del Estado nacional, con el consiguiente desarrollo de sus tres poderes: ejecutivo, legislativo y judicial. Cada uno de ellos tuvo a su cargo el control de las líneas de defensa y su desplazamiento; la sanción de las leyes que definieron los límites jurisdiccionales y los derechos de propiedad, público y privado, y la última instancia para dirimir los conflictos que surgieron en torno a esos derechos. El estudio se concentra sobre una zona de alta conflictividad, en la cual la definición de la propiedad demandó un largo proceso que se extendió desde 1875 hasta la última década del siglo XIX.In this paper we shall analyze the establishment of property rights on the land gained by advancing the frontier in 1869 and which was spread over an area where three provincial jurisdictions overlapped. We will describe the strategy used by one of the provinces – strategy defined as an incomplete transaction- in order to settle this conflict of interests among the provinces of Cordoba, Santa Fe and Buenos Aires. Our approach to the issue of property rights of border lands takes into account the institutional changes brought about by the strengthening of the Central Government and the development of the Executive, Legislative and Judicial powers. Each of these had a role in the control of

Three-dimensional geologic model of the southeastern Espanola Basin, Santa Fe County, New Mexico

Science.gov (United States)

Pantea, Michael P.; Hudson, Mark R.; Grauch, V.J.S.; Minor, Scott A.

2011-01-01

This multimedia model and report show and describe digital three-dimensional faulted surfaces and volumes of lithologic units that confine and constrain the basin-fill aquifers within the Espanola Basin of north-central New Mexico. These aquifers are the primary groundwater resource for the cities of Santa Fe and Espanola, six Pueblo nations, and the surrounding areas. The model presented in this report is a synthesis of geologic information that includes (1) aeromagnetic and gravity data and seismic cross sections; (2) lithologic descriptions, interpretations, and geophysical logs from selected drill holes; (3) geologic maps, geologic cross sections, and interpretations; and (4) mapped faults and interpreted faults from geophysical data. Modeled faults individually or collectively affect the continuity of the rocks that contain the basin aquifers; they also help define the form of this rift basin. Structure, trend, and dip data not previously published were added; these structures are derived from interpretations of geophysical information and recent field observations. Where possible, data were compared and validated and reflect the complex relations of structures in this part of the Rio Grande rift. This interactive geologic framework model can be used as a tool to visually explore and study geologic structures within the Espanola Basin, to show the connectivity of geologic units of high and low permeability between and across faults, and to show approximate dips of the lithologic units. The viewing software can be used to display other data and information, such as drill-hole data, within this geologic framework model in three-dimensional space.

Diversidad de aves en el Centro Agropecuario Cotové, Santa Fe de Antioquia, Colombia

Directory of Open Access Journals (Sweden)

Caty Milena Martínez-Bravo

2013-12-01

Full Text Available En el Centro Agropecuario Cotové, en el municipio de Santa Fe de Antioquia (Colombia, se estudió la diversidad de aves utilizando las metodologías de puntos fijos de conteo y redes de niebla en cinco usos del suelo (Frutales, Sistema silvopastoril, Bosque secundario, Pastoreo con baja densidad de árboles y Pastos de corte, para analizar la influencia sobre la composición, riqueza y abundancia de la avifauna. Se registraron 6 633 individuos de 101 especies, de las cuales 11 especies son migratorias. En términos de abundancia, la mayoría de las especies fueron raras y pocas comunes. Los gremios alimenticios mejor representados fueron insectívoros y frugívoros. El índice de Shannon indica que el Sistema silvopastoril presenta los valores de diversidad alfa más altos y los frutales los más bajos. Los usos del suelo que compartieron más especies fueron sistema Silvopastoril y Pastoreo con baja densidad de árboles. La heterogeneidad ambiental del centro actúa de forma diferente para las especies, beneficia en su mayoría aves de baja y media especificidad de hábitat, y con preferencia de hábitats de borde y áreas abiertas, por lo que se deben implementar acciones de manejo dirigidas a la conservación de áreas de regeneración natural y conectividad entre usos del suelo, para que las poblaciones de especies de aves presentes en la zona puedan ser mantenidas en el tiempo.

Synthesis of Pd-coated FeCo@Fe/C core-shell nanoparticles: microwave-induced ‘top-down’ nanostructuring and decoration

CSIR Research Space (South Africa)

Fashedemi, OO

2013-01-01

Full Text Available We report a novel microwave-induced fast and efficient synthesis of sub-10 nm sized palladium-decorated FeCo@Fe core–shell nanoparticles (ca. 3–7 nm) from a large-sized FeCo@Fe (0.21–1.5 µm) precursor, suggesting ‘top-down’ nanosizing. The high...

Characterization of the emerald of Santa Terezinha de Goias by spectroscopy, fluorescence and X-ray difraction

International Nuclear Information System (INIS)

Lariucci, C.

1988-01-01

The purpose of this work is to characterize the emerald of Santa Terezinha de Goias-GO, according to their physical properties (refractive index and specific gravity); spectrographic (infrared, ultraviolet and visible absorption); electron paramagnetic resonance; chemical analysis; crystal structure and specially by the recognition of their mineral inclusions. The results of the refractive index measure for the emerald of Santa Terezinha de Goias-GO are n e (1.575-1.585) and n o (1.590-1.9600) and the birrefringence = 0.012; the specific gravity is between the highest of the world (2.745 (4) Mg. m -3 ). The near infrared and infrared absorption, show the presence, in the structural channels of the emerald, of gas carbonic and free water interacting with an ion (Fe and/or Na) in these channels. The ultraviolet and visible absorption spectra accused the presence of Cr 3+ replacing Al 3+ and Fe 3+ in the channels of the structure. The study of electron paramagnetic resonance confirmed these last results [pt

Genetic differentiation between marine iguanas from different breeding sites on the island of Santa Fe (Galapagos Archipelago).

Science.gov (United States)

Lanterbecq, Deborah; Glaberman, Scott; Vitousek, Maren Noelani; Steinfartz, Sebastian; Benavides, Edgar; Wikelski, Martin; Caccone, Adalgisa

2010-01-01

We studied patterns of genetic diversity within and among 5 populations (318 individuals) of Galápagos marine iguanas (Amblyrhynchus cristatus) from the island Santa Fé. Populations were separated by distances of 0.2 to 9.9 km. We sequenced 1182 base pairs of the mitochondrial control region and screened 13 microsatellite loci for variability. We also added data from 5 populations (397 individuals) sampled on 4 neighboring islands (Santa Cruz, Floreana, Espanola, and San Cristobal). The 5 Santa Fé populations, revealed as genetically distinct from populations on other islands, present relatively low levels of genetic diversity, which are similar for both microsatellite (average observed heterozygosity from 0.7686 to 0.7773) and mitochondrial DNA (mtDNA) markers (haplotypic and nucleotide diversity from 0.587 to 0.728 and from 0.00079 to 0.00293, respectively), and comparable with those observed in similar-sized sampling sites on other islands. There was frequency-based evidence of genetic structure between northern and southern sites on Santa Fé (F(st) of 0.0027-0.0115 for microsatellite and 0.0447-0.2391 for mtDNA), but the 4 southern sites showed little differentiation. Most of the intra-island genetic variation was allocated within rather than between sites. There was no evidence of sex-biased dispersal or population substructuring due to lek-mating behavior, suggesting that these 2 observed behaviors are not strong enough to leave an evolutionary signal on genetic patterns in this species.

The occupational health of Santa Claus

OpenAIRE

Straube, Sebastian; Fan, Xiangning

2015-01-01

Previous publications in the field of Santa studies have not focused on health and safety issues arising from Santa?s workplace activities. However, it should be acknowledged that unique occupational hazards exist for Santa Claus. Major occupational health issues affecting Santa are discussed, along with suggestions for future research directions.

XAFS Studies of Fe Doped PhTiO3 Nanoparticles

International Nuclear Information System (INIS)

Shibata, Tomohiro; Chattopadhyay, Soma; Lin Bin; Palkar, V. R.

2007-01-01

Fe K and Ti K edge XAFS studies are reported on Fe doped PbTiO3 nanoparticles down to the 10 nm size. Fe forms Fe3+ ions and substitute for Ti4+ ions. For 18 nm nanoparticles, the Fe and Ti environment is found to be quite different. For PbFe0.5Ti0.5O3, locally the structure remains distorted from bulk to 10 nm size although the average structure changes

Melting of Au and Al in nanometer Fe/Au and Fe/Al multilayers under swift heavy ions: A thermal spike study

International Nuclear Information System (INIS)

Chettah, A.; Wang, Z.G.; Kac, M.; Kucal, H.; Meftah, A.; Toulemonde, M.

2006-01-01

Knowing that Fe is sensitive to swift heavy ion irradiations whereas Au and Al are not, the behavior of nanometric metallic multilayer systems, like [Fe(3 nm)/Au(x)] y and [Fe(3 nm)/Al(x)] y with x ranging between 1 and 10 nm, were studied within the inelastic thermal spike model. In addition to the usual cylindrical geometry of energy dissipation perpendicular to the ion projectile direction, the heat transport along the ion path was implemented in the electronic and atomic sub-systems. The simulations were performed using three different values of linear energy transfer corresponding to 3 MeV/u of 208 Pb, 132 Xe and 84 Kr ions. For the Fe/Au system, evidence of appearance of a molten phase was found in the entire Au layer, provided the Au thickness is less than 7 nm and 3 nm for Pb and Xe ions, respectively. For the Fe/Al(x) system irradiated with Pb ions, the Al layers with a thickness less than 4 nm melt along the entire ion track. Surprisingly, the Fe layer does not melt if the Al thickness is larger than 2 nm, although the deposited energy surpasses the electronic stopping power threshold of track formation in Fe. For Kr ions melting does not occur in any of the multilayer systems

Aerial gamma ray and magnetic survey: Raton Basin Project. The Raton and Santa Fe Quadrangles of New Mexico. Final report

International Nuclear Information System (INIS)

1979-11-01

In 1978, EG and G geoMetrics collected 4955 line miles of high sensitivity airborne radiometric and magnetic data in New Mexico within the Raton and Santa Fe quadrangles. These quadrangles represent part of the Raton Basin Project. All radiometric and magnetic data for the two quadrangles were fully reduced and interpreted by geoMetrics, and are presented as three volumes; one Volume I covering both quadrangles and separate Volume II's for the individual quadrangles. Over 50% of the survey area is covered by flat lying Mesozoic and Cenozoic deposits of the southern Great Plains Province. The western and southern portions of the area contain a combination of Precambrian and Paleozoic igneous and metamorphic rocks. These rocks occur primarily within and in close proximity to the Sangre de Cristo Mountains and late Cenozoic volcanic deposits occur to the west of the mountains and in the Las Vegas Volcanic region. Uranium deposits are scattered throughout the region, but none are known to be economic at the time of this report

32 CFR Appendix D to Part 45 - State Directors of Veterans Affairs

Science.gov (United States)

2010-07-01

... 55155. Mississippi President, State Veterans Affairs Board, 120 North State Street, War Memorial..., Trenton, NJ 08608. New Mexico Director, Veterans Service Commission, P.O. Box 2324, Santa Fe, NM 87503...

Introduction and pinning of domain walls in 50 nm NiFe constrictions using local and external magnetic fields

International Nuclear Information System (INIS)

Zahnd, G.; Pham, V.T.; Marty, A.; Jamet, M.; Beigné, C.; Notin, L.; Vergnaud, C.; Rortais, F.; Vila, L.; Attané, J.-P.

2016-01-01

We study domain wall injection in 100 nm wide NiFe nanowires, followed by domain wall propagation and pinning on 50 nm wide constrictions. The injection is performed using local and external magnetic fields. Using several nucleation pad geometries, we show that at these small dimensions the use of an external field only does not allow obtaining a reproducible injection/pinning process. However, the use of an additional local field, created by an Oersted line, allows to nucleate a reversed domain at zero external applied field. Then, an external field of 5 mT enables the domain wall to propagate far from the Oersted line, and the pinning occurs reproducibly. We also show that notwithstanding the reproducibility of the pinning process, the depinning field is found to be stochastic, following a bimodal distribution. Using micromagnetic simulation we link two different DW configurations, vortex and transverse, to the two typical depinning fields. - Highlights: • Magnetic domain wall introduction and pinning in Permalloy nanowires with 50 nm wide constrictions. • Magnetic domain nucleation at zero external applied field. • Bimodal distribution of the domain wall configuration in the constriction.

High thermal stability in W/MgO/CoFeB/W/CoFeB/W stacks via ultrathin W insertion with perpendicular magnetic anisotropy

Energy Technology Data Exchange (ETDEWEB)

Liu, Yi; Yu, Tao [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhu, Zhengyong; Zhong, Huicai [Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029 (China); Khamis, Khamis Masoud [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhu, Kaigui, E-mail: kgzhu@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Key Laboratory of Micro-Nano Measurement-Manipulation and Physics, Ministry of Education, Beihang University, Beijing 100191 (China)

2016-07-15

The perpendicular magnetic anisotropy (PMA) of a series of top MgO/CoFeB/W stacks were studied. In these stacks, the thickness of CoFeB is limited in a range of 1.1–2.2 nm. It was found that the stack can still maintain PMA in a 1.9 nm thick CoFeB free layer. Besides, we investigated the thermal stability factor ∆ of a spin transfer torque magnetic random access memory (STT-MRAM) by inserting an ultra-thin W film of 0.8 nm between two CoFeB films. The result shows a clear PMA behavior for the samples with CoFeB thickness up to 2.5 nm, and an in-plane magnetic anisotropy (IMA) when the CoFeB is thicker than 2.5 nm. Moreover, the thermal stability factor ∆ of the CoFeB stack with W insertion is about 132 for a 50 nm size STT-MRAM device, which is remarkably improved compared to 112 for a sample without W insertion. Our results represent an alternative way to realize the endurance at high annealing temperature, high-density and high ∆ in STT-MRAM device by ultra-thin W insertion. - Highlights: • The MgO/CoFeB/W multilayer can still maintain PMA in a CoFeB thickness of 1.9 nm. • The sample with 2.5 nm thickness of CoFeB by W insertion can still maintain PMA. • The sample with W insertion can still maintain PMA until the annealing temperature as high as 350 °C. • The thermal stability factor ∆ of sample with W insertion could be increase to about 132 for a 50 nm size STT-MRAM device.

Use of Fe(III) oxalate for oxidativewastewater treatment; Einsatz von Fe(III)-Oxalat zur chemisch-oxidativen Abwasserbehandlung

Energy Technology Data Exchange (ETDEWEB)

Kim, S.M.; Vogelpohl, A. [Clausthal Univ., Clausthal-Zellerfeld (Germany). Inst. fuer Thermische Verfahrenstechnik

1998-08-01

Iron(III)-oxalate was used as an iron catalyst for the Photo Fenton reaction. Iron(III) oxalations ([Fe(C{sub 2}O{sub 4}){sub 3}]{sup 3-}) are reduced to Fe(II) by irradiation using near UV-light ({lambda} = 300 - 400 nm) or visible light ({lambda} > 400 nm). At the same time, CO{sub 2}{sup -} or C{sub 2}O{sub 4}{sup -}-radicals originate, which cause the secondary reduction of Fe(III) to Fe(II). By means of the photolytically regenerated Fe(II) ions, hydroxyl radicals are increasingly formed, so that the degradation of organic substances is accelerated. The work aimed to assess the catalytic effect of Fe(III) oxalate for photochemical oxidation processes and to establish the parameters influencing further treatment of leachate from a municipal waste sanitary landfill by means of technical-scale experiments. (orig.) [Deutsch] In der vorliegenden Arbeit wurde Eisen(III)-Oxalat als Eisenkatalysator fuer die Photo-Fenton-Reaktion eingesetzt. Eisen(III)-Oxalationen ([Fe(C{sub 2}O{sub 4}){sub 3}]{sup 3-}) werden durch Strahlung mit nahem UV-Licht ({lambda}=300 bis 400 nm) oder mit sichtbarem Licht ({lambda}>400 nm) zu Fe(II) reduziert. Gleichzeitig entstehen CO{sub 2}{sup .-} oder C{sub 2}O{sub 4}{sup .-}-Radikale, die eine sekundaere Reduktion von Fe(III) zu Fe(II) bewirken. Mit Hilfe der photolytiisch regenerierten Fe(II)-Ionen werden vermehrt Hydroxylradikale gebildet und damit die Abbaugeschwindigkeit der organischen Substanzen beschleunigt. Ziel der hier vorgestellten Arbeit war es, die katalytische Wirkung von Fe(III)-Oxalat fuer photochemische Oxidationsverfahren abzuschaetzen und die Einflussparameter zur weitergehenden Behandlung eines Deponiesickerwassers aus Hausmuelldeponie anhand von Technikumsversuchen zu ermitteln. (orig.)

Magnetocapacidad en nanopartículas de Fe3O4 y NiFe2O4

Directory of Open Access Journals (Sweden)

Mira, J.

2010-02-01

Full Text Available We have synthesized NiFe2O4 (φ∼ 6 nm and Fe3O4 (φ∼ 30 nm magnetic nanoparticles by solvothermal synthesis; furthermore the Fe3O4 nanoparticles have been coated with a SiO2 shell of approximately 5 nm of thickness by the Stöber method. In the study of the dielectric properties as a function of the frequency, temperature and applied magnetic field, we observe a magnetocapacitive behavior (MC at room temperature and under a moderate magnetic field (H=0.5T, that is specially important in the case of the Fe3O4, nanoparticles (MC≈ 6%. On the other hand, the NiFe2O4 and Fe3O4@SiO2 samples present smaller magnetocapacitive effects: MC≈ 2% y MC≈ 1%, respectively. These MC values, that are higher than those reported in the literature for other related magnetic nanoparticles, corroborate the theoretical model proposed by Catalán in which the combination of Maxwell-Wagner effects and magnetoresistance promote the appearance of stronger magnetocapacitive effects.Hemos preparado nanopartículas magnéticas de NiFe2O4 (φ∼ 6 nm y Fe3O4 (φ∼ 30 nm mediante el método de síntesis solvotermal; además estas últimas han sido recubiertas con una capa de SiO2 de unos 5 nm de espesor mediante el método de Stöber. Al estudiar el comportamiento dieléctrico en función de la frecuencia, temperatura y campo magnético aplicado, observamos un comportamiento magnetocapacitivo (MC a temperatura ambiente y bajo un campo magnético moderado (H= 0.5 T que es especialmente importante en el caso de las nanopartículas de Fe3O4 (MC≈ 6%. Por su parte las muestras de NiFe2O4 y Fe3O4@SiO2 presentan efectos magnetocapacitivos menores: MC≈ 2% y MC≈ 1%, respectivamente. Estos valores de MC, que son considerablemente superiores a los descritos hasta el momento para otras nanopartículas magnéticas, corroboran la predicción teórica de Catalán de que la combinación de efecto Maxwell-Wagner con efectos magnetorresitivos potencian la aparición de fen

Microbial-Physical Synthesis of Fe and Fe3O4 Magnetic Nanoparticles Using Aspergillus niger YESM1 and Supercritical Condition of Ethanol

Directory of Open Access Journals (Sweden)

Mai Abdeen

2016-01-01

Full Text Available Magnetic Fe and Fe3O4 (magnetite nanoparticles are successfully synthesized using Aspergillus niger YESM 1 and supercritical condition of liquids. Aspergillus niger is used for decomposition of FeSO4 and FeCl3 to FeS and Fe2O3, respectively. The produced particles are exposed to supercritical condition of ethanol for 1 hour at 300°C and pressure of 850 psi. The phase structure and the morphology measurements yield pure iron and major Fe3O4 spherical nanoparticles with average size of 18 and 50 nm, respectively. The crystal size amounts to 9 nm for Fe and 8 nm for Fe3O4. The magnetic properties are measured to exhibit superparamagnetic- and ferromagnetic-like behaviors for Fe and Fe3O4 nanoparticles, respectively. The saturation magnetization amounts to 112 and 68 emu/g for Fe and Fe3O4, respectively. The obtained results open new route for using the biophysical method for large-scale production of highly magnetic nanoparticles to be used for biomedical applications.

Microbial-Physical Synthesis of Fe and Fe_3O_4 Magnetic Nanoparticles Using Aspergillus niger YESM1 and Supercritical Condition of Ethanol

International Nuclear Information System (INIS)

Abdeen, M.; Sabry, S.; Ghozlan, H.; El-Gendy, A. A.; Carpenter, E.E.; El-Gendy, A. A.

2016-01-01

Magnetic Fe and Fe_3O_4 (magnetite) nanoparticles are successfully synthesized using Aspergillus niger YESM 1 and supercritical condition of liquids. Aspergillus niger is used for decomposition of FeSO_4 and FeCl_3 to FeS and Fe_2O_3, respectively. The produced particles are exposed to supercritical condition of ethanol for 1 hour at 300 degree and pressure of 850 psi. The phase structure and the morphology measurements yield pure iron and major Fe_3O_4 spherical nanoparticles with average size of 18 and 50 nm, respectively. The crystal size amounts to 9 nm for Fe and 8 nm for Fe_3O_4. The magnetic properties are measured to exhibit superparamagnetic- and ferromagnetic-like behaviors for Fe and Fe_3O_4 nanoparticles, respectively. The saturation magnetization amounts to 112 and 68 emu/g for Fe and Fe_3O_4, respectively. The obtained results open new route for using the biophysical method for large-scale production of highly magnetic nanoparticles to be used for biomedical applications

Influence of Fe underlayers on stress evolution of Ti in Ti/Fe multilayers

Energy Technology Data Exchange (ETDEWEB)

Wan, Li; Thompson, Gregory, E-mail: gthompson@eng.ua.edu [Department of Metallurgical Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0202 (United States)

2016-11-15

A series of 40–2 nm bilayer spacing Ti/Fe multilayers were sputter-deposited. As the length scale of individual Ti layers equaled to 2 nm, Ti phase transforms from a hexagonal close packed (hcp)-to-body centered cubic (bcc) crystal structures for equal layer thicknesses in Ti/Fe multilayers. Further equal reductions in bilayer spacing to less than 1 nm resulted in an additional transformation from a crystalline to amorphous structure. Atom probe tomography reveals significant intermixing between layers which contributes to the observed phase transformations. Real-time, intrinsic growth stress measurements were also performed to relate the adatom mobility to these phase transformations. For the hcp Ti/bcc Fe multilayers of equivalent volume fractions, the multilayers undergo an overall tensile stress state to a compressive stress state with decreasing bilayer thickness for the multilayers. When the above phase transformations occurred, a modest reduction in the overall compressive stress of the multilayer was noted. Depending on the Fe thickness, the Ti growth was observed to be a tensile to compressive growth change to a purely compressive growth for thinner bilayer spacing. Fe retained a tensile growth stress regardless of the bilayer spacing studied.

Moluscos asociados a las raíces sumergidas del mangle rojo Rhizophora mangle, en el Golfo de Santa Fe, Estado Sucre, Venezuela

Directory of Open Access Journals (Sweden)

B. Márquez

2002-12-01

Full Text Available Se realizó un estudio mensual cualitativo y cuantitativo de la comunidad de moluscos asociados a las raíces sumergidas del mangle rojo, Rhizophora mangle, entre octubre de 1998 y septiembre de 1999, en seis estaciones del Golfo de Santa Fe (Estado Sucre, Venezuela. Se colectaron e identificaron un total de 4 704 individuos pertenecientes a 45 especies de moluscos (22 gasterópodos, 15 bivalvos y 8 polyplacóforos. Las especies más abundantes fueron: Crassostrea rhizophorae, Isognomon bicolor L alatus y Brachidontes exustus. Los valores más altos de diversidad y equitabilidad, y los menores valores de dominancia, se encontraron en las estaciones tres y cuatro, mientras que lo opuesto ocurrió en las estaciones uno y dos. El análisis de afinidad mostró que en las cinco primeras estaciones las variaciones espaciales en la composición de la comunidad son mayores que las variaciones temporales, mientras que en la estación seis priman las diferencias temporales. Se encontraron factores que podrían ser importantes para determinar la estructura de la comunidad, como vecindad a otros ecosistemas y/6 aspectos biológicos específicos de las especies como adaptaciones a condiciones fluctuantes, hábitos alimenticios y migración en busca de ambientes sombreados y protegidos.A qualitative and quantitative monthly study of the mollusks community associated to the submered roots of the red mangrove, Rhizophora mangle (L., between October of 1998 and September of 1999, in six stations of the Gulf of Santa Fe. (Suere State, Venezuela. Were collected 4 704 specimens, 45 species of mollusks were identified (22 gastropods, 15 bivalves and 8 chitons. The most abundant species were: Crassostrea rhizophorae, Isognomon bicolor, L alatus and Brachidontes exustus. The highest values in diversity and evenness, and the smallest dominant values, were in the stations three and four, while the opposed happened in the stations one and two. The analysis of likeness

Morphology, magnetic and resonance properties of Fe/MgO multilayers

International Nuclear Information System (INIS)

Garcia-Garcia, A; Algarabel, P A; Ibarra, M R; Vovk, A; Strichovanec, P; Pardo, J A; Magen, C; Golub, V; Salyuk, O

2011-01-01

Magnetic, resonance and transport properties of Fe(t nm)/MgO(3.0 nm) multilayers prepared by pulsed laser deposition were investigated. Comparison of the data allows conclusions on Fe layers morphology. For t 1.25 nm a continuous coverage of MgO by Fe takes place. However, the morphology of Fe layers is rough. This causes the appearance of magnetostatic resonance modes analogous to those observed for continuous films deposited on embossed surfaces.

Study on the depth profile analysis of Fe/Co intermixing in [SmCo{sub 5}/Fe]{sub 11} magnetic multilayers

Energy Technology Data Exchange (ETDEWEB)

Saravanan, P., E-mail: psdrdo@gmail.com [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Perumal, A.; Gayen, Anabil [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Reddy, G.L.N.; Kumar, Sanjiv [National Centre for Compositional Characterization of Materials, Bhabha Atomic Research Centre, ECIL Post, Hyderabad 500062 (India); Kamat, S.V. [Defence Metallurgical Research Laboratory, Hyderabad 500058 (India)

2014-09-01

Multilayer films were sputtered on Si (1 0 0) substrate by following a layer sequence of Cr (10 nm)/[Fe (4 nm)/SmCo{sub 5} (20 nm)]{sub 11}/Cr (90 nm) at room temperature and subsequently, subjected to two-stage annealing. The phase composition, the extent of inter-diffusion at the SmCo{sub 5}/Fe interfaces and the magnetic properties of multilayered samples were investigated by X-ray diffraction (XRD), RBS and super-conducting quantum interference device (SQUID), respectively. The XRD studies showed the crystallization of SmCo{sub 5}-phase in the hard layer along with a bcc-Fe (Co)-phase in the soft layer, while the RBS depth profile analysis revealed the changes that occur in the effective Fe-layer thickness and diffused Co-content as minimal for the Fe-layer index, n{sub Fe}≤5. A single-phase behavior associated with strong in-plane anisotropy was evidenced with the SQUID measurements. The observed remanence enhancement (1020 kA/m) and energy product value (286 kJ/m{sup 3}) in these multilayers are discussed in the context of Fe-layer thickness and diffused Co-content.

Superconducting spin valve effect in Fe/In based heterostructures

Energy Technology Data Exchange (ETDEWEB)

Leksin, Pavel; Schumann, Joachim; Kataev, Vladislav; Schmidt, Oliver; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Garifyanov, Nadir; Garifullin, Ilgiz [Zavoisky Physical-Technical Institute, Kazan Scientific Center, Russian Academy of Sciences (Russian Federation)

2015-07-01

We report on magnetic and superconducting properties of the spin-valve multilayer system CoOx/Fe1/Cu/Fe2/In. The Superconducting Spin Valve Effect (SSVE) assumes the T{sub c} difference between parallel (P) and antiparallel (AP) orientations of the Fe1 and Fe2 layers' magnetizations. The SSVE value oscillates and changes its sign when the Fe2 layer thickness d{sub Fe2} is varied from 0 to 5 nm. The SSVE value is positive, as expected, in the range 0.4 nm ≤ d{sub Fe2} ≤ 0.8 nm. For a rather broad range of thicknesses 1 nm ≤ d{sub Fe2} ≤ 2.6 nm the SSVE has negative sign assuming the inverse SSVE. Moreover, the magnitude of the inverse effect is larger than that of the positive direct effect. We attribute these oscillations to a quantum interference of the cooper pair wave functions in the magnetic part of the system. For most of the spin-valve samples from this set we experimentally realized the full switching between normal and superconducting states due to direct and inverse SSVE. The analysis of the experimental data has enabled the determination of all microscopic parameters of the studied system.

Synthesis and electrical conductivity of nanocrystalline tetragonal FeS

International Nuclear Information System (INIS)

Zeng Shu-Lin; Wang Hui-Xian; Dong Cheng

2014-01-01

A convenient method for synthesis of tetragonal FeS using iron powder as iron source, is reported. Nanocrystalline tetragonal FeS samples were successfully synthesized by reacting metallic iron powder with sodium sulfide in acetate buffer solution. The obtained sample is single-phase tetragonal FeS with lattice parameters a = 0.3767 nm and c = 0.5037 nm, as revealed by X-ray diffraction. The sample consists of flat nanosheets with lateral dimensions from 20 nm up to 200 nm and average thickness of about 20 nm. We found that tetragonal FeS is a fairly good conductor from the electrical resistivity measurement on a pellet of the nanosheets. The temperature dependence of conductivity of the pellet was well fitted using an empirical equation wherein the effect of different grain boundaries was taken into consideration. This study provides a convenient, economic way to synthesize tetragonal FeS in a large scale and reports the first electrical conductivity data for tetragonal FeS down to liquid helium temperature. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Cuidado y Protección. Las Medidas de Protección de Derechos en la Provincia de Santa Fe, Argentina.

Directory of Open Access Journals (Sweden)

Silvina Laura Fernández

2016-04-01

Full Text Available Resumo: As adaptações normativas dos países á Convenção Internacional sobre os direitos da criança (1990 foram suscitando debates, controvérsias e ensaios entre os atores sociais, políticos e judiciários sob como tornar consistentes as mudanças propostas. Este artigo tem o objetivo de contribuir a expor as racionalidades, tensões e disputas entre os atores do campo da criança e do adolescente sob as medidas excepcionais estabelecidas pela lei de proteção integral a criança e ao adolescente no Estado de Santa Fe, Argentina (No 12927/09 Tais medidas têm revertidos nos procedimentos no qual se decreta a perda o suspensão do poder familiar. No caso da pesquisa e no analise dos depoimentos coletados, o estudo reconstrói os argumentos que guiaram o tema tanto no grupo de pais adotantes como no Foro de Infâncias Rosário nos primeiros anos do Sistema de Proteção de Direitos no Estado. Assim, o cuidado torna se hoje uma categoria privilegiada a fim de objetivar os diferentes argumentos sobre as responsabilidades sociais e da família em relação à minoria de idade nos processo administrativos e judiciários. O estudo nota seu ponto de condensação na transformação normativa do ano 2011. Palavras-chave: Infância; Políticas; Proteção; Direitos; Cuidado *** Resumen: Las adecuaciones normativas de los países a la Convención Internacional sobre los Derechos del Niño (1989 fueron suscitando  interrogantes, controversias y ensayos entre los actores sociales, políticos y judiciales sobre cómo tornar consistentes las transformaciones propuestas. El artículo tiene como objeto exponer las racionalidades, tensiones y disputas entre los actores del campo de la infancia sobre las medidas excepcionales establecidas por la ley de protección de derechos de niñas, niños y adolescentes en la provincia de Santa Fe, Argentina (N°12.927/09. Dichas medidas consisten en el proceso burocrático a través del cual un infante es separado

Morphology, magnetic and resonance properties of Fe/MgO multilayers

Energy Technology Data Exchange (ETDEWEB)

Garcia-Garcia, A; Algarabel, P A; Ibarra, M R [Instituto de Ciencia de Materiales de Aragon, Universidad de Zaragoza-CSIC 50009 Zaragoza (Spain); Vovk, A [Centro de Fisica da Materia Condensada Unversidade de Lisboa, Campo Grande Ed. C8, 1749-016, Lisboa (Portugal); Strichovanec, P; Pardo, J A; Magen, C [Instituto de Nanociencia de Aragon, Universidad de Zaragoza 50018 Zaragoza (Spain); Golub, V; Salyuk, O, E-mail: ayvovk@fc.ul.pt [Institute of Magnetism NAS of Ukraine, 36-b Vernnadsky blvd., 03142, Kyiv (Ukraine)

2011-07-06

Magnetic, resonance and transport properties of Fe(t nm)/MgO(3.0 nm) multilayers prepared by pulsed laser deposition were investigated. Comparison of the data allows conclusions on Fe layers morphology. For t<0.61 nm typical features of granular cermet films in dielectric regime are observed, i.e. high electrical resistance, isotropic magnetoresistance and strong temperature dependence of magnetization. For higher t coalescence of Fe granules occurs and metallic percolation cluster is formed at t{approx}0.81 nm. This is manifested by rapid decrease of films resistance and formation of multipeak ferromagnetic resonance spectra. For t>1.25 nm a continuous coverage of MgO by Fe takes place. However, the morphology of Fe layers is rough. This causes the appearance of magnetostatic resonance modes analogous to those observed for continuous films deposited on embossed surfaces.

All-optical measurement of interlayer exchange coupling in Fe/Pt/FePt thin films

Science.gov (United States)

Berk, C.; Ganss, F.; Jaris, M.; Albrecht, M.; Schmidt, H.

2018-01-01

Time Resolved Magneto Optic Kerr Effect spectroscopy was used to all-optically study the dynamics in exchange coupled Fe(10 nm)/Pt(x = 0-5 nm)/FePt (10 nm) thin films. As the Pt spacer decreases, the effective magnetization of the layers is seen to evolve towards the strong coupling limit where the two films can be described by a single effective magnetization. The coupling begins at x = 1.5 nm and reaches a maximum exchange coupling constant of 2.89 erg/cm2 at x = 0 nm. The films are ferromagnetically coupled at all Pt thicknesses in the exchange coupled regime (x ≤ 1.5 nm). A procedure for extracting the interlayer exchange constant by measuring the magnetic precession frequencies at multiple applied fields and angles is outlined. The dynamics are well reproduced using micromagnetic simulations.

PUENTES ENTRE LA EXTENSIÓN, LA INVESTIGACIÓN Y LA CIUDADANÍA SEXUAL: EL CASO DEL MONITOREO SOCIAL DE POLÍTICAS PÚBLICAS EN SALUD SEXUAL Y REPRODUCTIVA EN LA PROVINCIA DE SANTA FE

OpenAIRE

Pagura, Fernanda; Molina, Adriana; Cánaves, Violeta; Trevisi, Maica

2011-01-01

En un trabajo articulado y sostenido en el tiempo desde el año 2006 entre el Programa de Extensión “Género, Sociedad y Universidad perteneciente a la Universidad Nacional del Litoral y Organizaciones de la sociedad civil de la provincia de Santa Fe, se han generado diferentes acciones a partir de un objetivo común: monitorear la plena aplicabilidad de la Ley 11.888 (Programa provincial de salud reproductiva y procreación responsable) y la accesibilidad en igualdad de condiciones de parte de l...

Very high coercivities of top-layer diffusion Au/FePt thin films

International Nuclear Information System (INIS)

Yuan, F.T.; Chen, S.K.; Liao, W.M.; Hsu, C.W.; Hsiao, S.N.; Chang, W.C.

2006-01-01

The Au/FePt samples were prepared by depositing a gold cap layer at room temperature onto a fully ordered FePt layer, followed by an annealing at 800 deg. C for the purpose of interlayer diffusion. After the deposition of the gold layer and the high-temperature annealing, the gold atoms do not dissolve into the FePt Ll 0 lattice. Compared with the continuous FePt film, the TEM photos of the bilayer Au(60 nm)/FePt(60 nm) show a granular structure with FePt particles embedded in Au matrix. The coercivity of Au(60 nm)/FePt(60 nm) sample is 23.5 kOe, which is 85% larger than that of the FePt film without Au top layer. The enhancement in coercivity can be attributed to the formation of isolated structure of FePt ordered phase

76 FR 70120 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2011-11-10

... Trail, Suite B, Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or Email: msantistevan... Watch NM. 4 p.m. Presentation on Waste Disposal, Robert Neill. 5 p.m. Dinner Break. 6 p.m. Public... will be available by writing or calling Menice Santistevan at the address or phone number listed above...

Distribución de serotipos de Streptococcus pneumoniae aislados de infecciones invasoras en el Hospital de Niños de Santa Fe Serotype distribution of Streptococcus pneumoniae isolated from invasive infections at the Hospital de Niños of Santa Fe.

Directory of Open Access Journals (Sweden)

C. Mayoral

2008-03-01

Full Text Available Con la introducción de vacunas conjugadas antineumocócicas se observó, en muchos países, disminución de aislamientos de Streptococcus pneumoniae del serotipo 14 y aumento de aislamientos correspondientes a serotipos no incluidos en esas vacunas. En 1993, el Hospital de Niños de Santa Fe comenzó la vigilancia de la distribución de serotipos de Streptococcus pneumoniae invasores. En este trabajo se estudió la correlación entre serotipo y a patología (neumonía/meningitis, b edad (menor o mayor de dos años, y c CIM de penicilina, para los serotipos aislados en el período 2003-2005. El serotipo predominante fue el 14, seguido del 1, 6B, 18C, 7F, 19F y 5. El serotipo 14 mostró asociación estadísticamente significativa con valores de CIM de penicilina entre 0,5 y 2 mg/l, no así con alguna patología, aunque se lo halló con mayor frecuencia en neumonías que en meningitis. Los serotipos 14 y 1 prevalecieron en niños menores y mayores de 2 años, respectivamente. La CIM de penicilina = 2 mg/l se observó más en neumonías que en meningitis. La frecuencia relativa de los diferentes serotipos hallados fue semejante a la observada en el período 1993-99; no obstante, los serotipos 18C, 4, 12F y 22F no se habían encontrado antes. La aparición de nuevos serotipos convierte en importante la vigilancia, dada la necesidad de formular vacunas que los incluyan y que efectivamente prevengan las infecciones neumocócicas más comunes.The serotype distribution of Streptococcus pneumoniae varies through time. The introduction of pneumococcal conjugate vaccines showed a decreased prevalence of pneumococcal invasive isolates belonging to serotype 14 and an increase of serotypes not therein included. In 1993, the Hospital de Niños of Santa Fe began surveillance of the serotype distribution of invasive S. pneumoniae disease. In the period 2003 - 2005, 76 isolates were analysed by studying the correlation between serotype and pathology, age and MIC

Fe3O4 and metal-organic framework MIL-101(Fe) composites catalyze luminol chemiluminescence for sensitively sensing hydrogen peroxide and glucose.

Science.gov (United States)

Qian Tang, Xue; Dan Zhang, Yi; Wei Jiang, Zhong; Mei Wang, Dong; Zhi Huang, Cheng; Fang Li, Yuan

2018-03-01

In this work, Fe 3 O 4 and metal-organic framework MIL-101(Fe) composites (Fe 3 O 4 /MIL-101(Fe)) was demonstrated to possess excellent catalytic property to directly catalyze luminol chemiluminescence without extra oxidants. We utilized Fe 3 O 4 /MIL-101(Fe) to develop a ultra-sensitive quantitative analytical method for H 2 O 2 and glucose. The possible mechanism of the chemiluminescence reaction had been investigated. Under optimal conditions, the relative chemiluminescence intensity was linearly proportional to the logarithm of H 2 O 2 concentration in the range of 5-150nM with a limit of detection of 3.7nM (signal-to-noise ratio = 3), and glucose could be linearly detected in the range from 5 to 100nM and the detection limit was 4.9nM (signal-to-noise ratio = 3). Furthermore, the present approach was successfully applied to quantitative determination of H 2 O 2 in medical disinfectant and glucose in human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Kerr microscopy study of exchange-coupled FePt/Fe exchange spring magnets

Energy Technology Data Exchange (ETDEWEB)

Hussain, Zaineb; Kumar, Dileep [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Reddy, V. Raghavendra, E-mail: varimalla@yahoo.com [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Noida 201303 (India)

2017-05-15

Magnetization reversal and magnetic microstructure of top soft magnetic layer (Fe) in exchange spring coupled L1{sub 0} FePt/Fe is studied using high resolution Kerr microscopy. With remnant state of the hard magnetic layer (L1{sub 0} FePt) as initial condition, magnetization loops along with magnetic domains are recorded for the top soft magnetic layer (Fe) using Kerr microscopy. Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. It is also observed that one can tune the magnitude of hysteresis shift by reaching the remanent state from different saturating fields (H{sub SAT}) and also by varying the angle between measuring field and H{sub SAT}. The hysteresis loops and magnetic domains of top soft Fe layer demonstrate unambiguously that soft magnetic layer at remanent state in such exchange coupled system is having unidirectional anisotropy. An analogy is drawn and the observations are explained in terms of established model of exchange bias phenomena framed for field-cooled ferromagnetic - antiferromagnetic bilayer systems. - Highlights: • Kerr microscopy of top soft magnetic Fe layer in exchange spring coupled L1{sub 0} FePt (30 nm)/Fe (22 nm) is reported. • Considerable shifting of Fe layer hysteresis loop from center which is similar to exchange bias phenomena is observed. • Tuneable nature of magnitude of hysteresis shift is shown. • It is unambiguously shown that the top soft Fe magnetic layer at remanent state is having unidirectional anisotropy.

Corroded microstructure of HDDR-NdFeB magnetic powders

International Nuclear Information System (INIS)

Zhu, L.Y.; Itakura, M.; Tomokiyo, Y.; Kuwano, N.; Machida, K.

2004-01-01

The microstructure of corroded HDDR-NdFeB magnetic powders in bonded magnet has been investigated by transmission electron microscopy. Following an exposure time of 300 h at 398 K in air, the HDDR-NdFeB magnetic powders are found covered with an altered layer about 300 nm thick on the surface. The layer is composed of α-Fe grains 5-10 nm in diameter and h-Nd 2 O 3 grains smaller than 5 nm. Under the altered layer, corrosion has proceeded along the Nd 2 (Fe,Co) 14 B grain boundaries to leave a wetting layer composed of a dense mixture of α-Fe and h-Nd 2 O 3 phase. The appearance of α-Fe grains in both of the altered layer wetting layer leads to the high magnetic flux loss of the corroded HDDR-NdFeB bonded magnet

Nanostructure and magnetization reversal process in TbFeCo/Yx(FeCo)1-x spring-magnet type multilayers

International Nuclear Information System (INIS)

Duc, N.H.; Huong Giang, D.T.; Chau, N.

2004-01-01

Studies of the naturally formed nanostructure and magnetization reversal process were performed for the sputtered Tb(Fe 0.55 Co 0.45 ) 1.5 /Y x (Fe 0.7 Co 0.3 ) 1-x multilayers (0≤x≤0.2) with a TbFeCo layer thickness t TbFeCo =12 nm and YFeCo layer thickness t YFeCo =10 nm. The structural investigations showed that nanocrystals are naturally formed and coexist within the amorphous matrix in Y 0.1 (FeCo) 0.9 layers. In this state, low magnetic coercivity and large parallel magnetostrictive susceptibility are observed. The results are discussed in terms of the crystalline discontinuity of the soft YFeCo layers

Ordering process of sputtered FePt films

International Nuclear Information System (INIS)

Takahashi, Y.K.; Ohnuma, M.; Hono, K.

2003-01-01

We have investigated the in situ ordering process of sputtered FePt thin films deposited on heated substrates at 300 deg. C with different thicknesses. The films thinner than 50 nm were composed of nanograins (∼5 nm) of disordered FePt phase. Recrystallization occurred when films were grown thicker than 100 nm, and transformation twins were observed in recrystallized grains, in which ordering to the L1 0 structure was confirmed

Electrical conductivity in Fe_2O_3 and CoFe_2O_4 nanoparticle arrays and their application in gas sensing

International Nuclear Information System (INIS)

Luby, S.; Benkovicova, M.; Jergel, M.; Siffalovic, P.; Majkova, E.; Rella, R.; Capone, S.; Manera, M. G.

2013-01-01

In this paper we summarize the results obtained as a by product of γ-Fe_2O_3 and CoFe_2O_4 sensors testing. Monodisperse γ-Fe_2O_3 and CoFe_2O_4 NPs with the size of 6.4 ± 0.6 and 7.6 ± 0.6 nm, respectively, were synthesized by high-temperature solution phase reaction from methyl acetylacetonates. The thickness of surfactant is 1 nm and 0.8 nm for two types of NPs, respectively. Surfactant stops the growth of NPs at a certain size. The self-assembled NP monolayers were prepared by Langmuir-Blodgett technique from the colloid solutions spread on the water sub-phase in a standard LB trough. M = 1, 2, 4 or 10 NP monolayers (L) were deposited onto auxiliary oxidized Si substrates or onto 2 mm x 2 mm Al_2O_3 sensor substrates equipped with 20 nm Ti/500 nm Pt comb electrodes to read the measuring current and with 20 nm Ti/500 nm Pt meander on the back side for the heating of the structure to a working temperature. Material properties of NPs and arrays were studied by SEM/EDS, GI XRD, GISAXS, XANES and ellipsometry. (authors)

Mumps in a district primary school at the locality of Santa Fe, Bogota (Colombia 2010.

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Oneida Castañeda

2010-12-01

Full Text Available Background. Epidemic parotitis (“mumps” is a human viral infection which affects mainly the salivary glands; its peak incidence afflicts children 5 to 9-year. At epidemiologic week (EW 40/2010, the Centro Oriente II Level Hospital received a community report about a mumps outbreak in a District Primary School (DPS, eastwards of the locality of Santa Fe (Bogotá. The hospital’s epidemiology office sent a response team to investigate the situation and to guide prevention & control actions. Methods. The team made an outbreak descriptive study; field investigation included description time-place-person; case-definition as patient with active clinical condition of parotitis; Active Institutional Search (AIS and house visitations; study variables matched those of the official individual notification report. Data were registered and analyzed using Epi -Info 3.5.1® with frequency, central trend and association measurements. Results. 14 mumps cases were identified: 1 adult and 13(93% children; 5(35,7% were girls; median age was 11,9 year (range 7-40. Four cases (28,6% were confirmed by clinical signs, 10(71,4% by epidemiologic link; no one was hospitalized. 12 patients (86% had unknown vaccination status; 11 cases (78% produced neither the vaccination card nor any additional information. Index case occurred at EW30/2010 and the epidemic peak occurred at EW34/2010; attack rate was 8.1%. Conclusions. Epidemiology office confirmed mumps outbreak, delayed notification and impossibility to verify vaccination records. The response team recommended the DPS to strengthen biosafety measures; and advised local health institution to increase epidemiologic surveillance & control activities, adherence to national mumps protocol, school vaccination and to promote information, communication, education strategies on importance of vaccination and cards right use.

Novel solid-state synthesis of α-Fe and Fe3O4 nanoparticles embedded in a MgO matrix

Science.gov (United States)

Schneeweiss, O.; Zboril, R.; Pizurova, N.; Mashlan, M.; Petrovsky, E.; Tucek, J.

2006-01-01

Thermally induced reduction of amorphous Fe2O3 nanopowder (2-3 nm) with nanocrystalline Mg (~20 nm) under a hydrogen atmosphere is presented as a novel route to obtain α-Fe and Fe3O4 magnetic nanoparticles dispersed in a MgO matrix. The phase composition, structural and magnetic properties, size and morphology of the nanoparticles were monitored by x-ray diffraction, 57Fe Mössbauer spectroscopy at temperatures of 24-300 K, transmission electron microscopy and magnetic measurements. Spherical magnetite nanoparticles prepared at a reaction temperature of 300 °C revealed a well-defined structure, with a ratio of tetrahedral to octahedral Fe sites of 1/2 being common for the bulk material. A narrow particle size distribution (20-30 nm) and high saturation magnetization (95 ± 5 A m2 kg-1) predispose the magnetite nanoparticles to various applications, including magnetic separation processes. The Verwey transition of Fe3O4 nanocrystals was found to be decreased to about 80 K. The deeper reduction of amorphous ferric oxide at 600 °C allows α-Fe (40-50 nm) nanoparticles to be synthesized with a coercive force of about 30 mT. They have a saturation magnetization 2.2 times higher than that of synthesized magnetite nanoparticles, which corresponds well with the ratio usually found for the pure bulk phases. The magnetic properties of α-Fe nanocrystals combined with the high chemical and thermal stability of the MgO matrix makes the prepared nanocomposite useful for various magnetic applications.

Investigation of genotoxic potential of various sizes Fe2O3 nanoparticles with comet assay

Directory of Open Access Journals (Sweden)

İbrahim Hakkı Ciğerci

2015-06-01

In this study, genotoxic potential of <50 nm and <100 nm Fe2O3 nanoparticles were investigated by using Comet Assay. Allium cepa root meristems were exposed with five doses (0.001, 0.01, 0.1, 1, 10 mM of <50 nm for 4 hour and three doses (2.5, 5 (EC50, 10 mM for <100 nm of Fe2O3 nanoparticle for 24 and 96 h. Methyl methanesulfonate -MMS (10 ppm was used as a positive control. The results were also analyzed statistically by using SPSS by Windows, 18.0. It was determined that different doses of <50 nm Fe2O3 nanoparticle have no genotoxic effect of DNA. Different doses of <100 nm Fe2O3 have no genotoxic but only 10 mM dose have genotoxic effect on DNA. When compared <50 nm with <100 nm of Fe2O3 nanoparticle; <50 nm have more effects than <100 nm of Fe2O3 on DNA damage.

Santa and the Moon

NARCIS (Netherlands)

Barthel, P.

This article reflects on the use of illustrations of the Moon in images of Santa Claus, on Christmas gift-wrapping paper and in children's books, in two countries which have been important in shaping the image of Santa Claus and his predecessor Sinterklaas: the USA and the Netherlands. The

Room temperature luminescence and ferromagnetism of AlN:Fe

Energy Technology Data Exchange (ETDEWEB)

Li, H., E-mail: lihui@mail.iee.ac.cn, E-mail: wjwang@aphy.iphy.ac.cn [The Key Laboratory of Solar Thermal Energy and Photovoltaic System, Institute of Electrical engineering, Chinese Academy of Sciences, Beijing 100190 (China); Cai, G. M. [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Wang, W. J., E-mail: lihui@mail.iee.ac.cn, E-mail: wjwang@aphy.iphy.ac.cn [Research and Development Center for Functional Crystals, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2016-06-15

AlN:Fe polycrystalline powders were synthesized by a modified solid state reaction (MSSR) method. Powder X-ray diffraction and transmission electron microscopy results reveal the single phase nature of the doped samples. In the doped AlN samples, Fe is in Fe{sup 2+} state. Room temperature ferromagnetic behavior is observed in AlN:Fe samples. Two photoluminescence peaks located at about 592 nm (2.09 eV) and 598 nm (2.07 eV) are observed in AlN:Fe samples. Our results suggest that AlN:Fe is a potential material for applications in spintronics and high power laser devices.

Observation and analysis of X-ray spectra of highly-ionized atoms produced by laser irradiation in the wavelength range 0.60 nm to 0.95 nm

International Nuclear Information System (INIS)

Wyart, J.-F.; Ecole Polytech., Palaiseau; Fajardo, M.; Missalla, T.; Gauthier, J.-C.; Chenais-Popovics, C.; Klopfel, D.; Uschmann, I.; Foerster, E.

1999-01-01

The spectra of highly-charged ions produced by laser irradiation on flat targets at about 5 x 10 14 Wcm -2 are recorded in the range from 0.60 nm to 0.95 nm (6 A to 9.5 A) by means of two spectrographs (a flat ADP crystal and a Johann SiO 2 crystal spectrograph). The identification of the lines is supported by calculations of energies and transition probabilities in the relativistic parametric potential model. New identifications in several spectra of iron (Fe XXIII to Fe XXI), sodium-like strontium, Sr XXVIII, magnesium-like indium. In XXXVIII, and cobalt-like samarium, Sm XXXVI, are given. In the case of Fe XXIII, relativistic and non-relativistic (Cowan) ab initio calculations are compared. (orig.)

Profound Interfacial Effects in CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4 Core/Shell Nanoparticles

Science.gov (United States)

Polishchuk, Dmytro; Nedelko, Natalia; Solopan, Sergii; Ślawska-Waniewska, Anna; Zamorskyi, Vladyslav; Tovstolytkin, Alexandr; Belous, Anatolii

2018-03-01

Two sets of core/shell magnetic nanoparticles, CoFe2O4/Fe3O4 and Fe3O4/CoFe2O4, with a fixed diameter of the core ( 4.1 and 6.3 nm for the former and latter sets, respectively) and thickness of shells up to 2.5 nm were synthesized from metal chlorides in a diethylene glycol solution. The nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The analysis of the results of magnetic measurements shows that coating of magnetic nanoparticles with the shells results in two simultaneous effects: first, it modifies the parameters of the core-shell interface, and second, it makes the particles acquire combined features of the core and the shell. The first effect becomes especially prominent when the parameters of core and shell strongly differ from each other. The results obtained are useful for optimizing and tailoring the parameters of core/shell spinel ferrite magnetic nanoparticles for their use in various technological and biomedical applications.

Nearly Finished Genomes Produced Using Gel Microdroplet Culturing (Seventh Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting 2012)

Energy Technology Data Exchange (ETDEWEB)

Fitzsimmons, Michael

2012-06-01

Michael Fitzsimmons from Los Alamos National Laboratory gives a talk titled "Nearly Finished Genomes Produced Using Gel Microdroplet Culturing" at the 7th Annual Sequencing, Finishing, Analysis in the Future (SFAF) Meeting held in June, 2012 in Santa Fe, NM.

Breakfast habit and quality in students from two public primary schools in the city of Santa Fe.

Science.gov (United States)

Fugas, Valeria; Berta, Eugenia; Walz, Florencia; Fortino, Ma Alejandra; Martinelli, Marcela J

2013-12-01

Breakfast provides the necessary energy and nutrients to achieve an optimal physical and mental performance. OBJECTIVE. To find out breakfast frequency, factors that influence breakfast habit and skipping, breakfast quality and snack intake in children from public schools in the city of Santa Fe. POPULATION AND METHODS. Descriptive, cross-sectional study. A total of 637 students were assessed using a closed-ended question survey. RESULTS. Seventy five percent of children had breakfast on a daily basis; only 1.6% had a good quality breakfast. Eating breakfast every day or some days did not depend on having the company of a family member. In the case of first to fifth grade children, the weekly frequency depended on having a family member who made it (p= 0.04). The main cause for skipping breakfast was lack of time. Twenty-three percent of children in sixth and seventh grade indicated feeling unwell when having breakfast. More than 50% of children watched television while having breakfast. Most students in first to third grade had breakfast that could be improved (41%) and which was insufficient (41%). An insufficient quality breakfast was more common among fourth and fifth grade students (50%). A remarkable piece of information is the number of sixth and seventh grade children who had a poor quality breakfast (16%). Very few children had a snack that was appropriate to supplement the final quality of breakfast. CONCLUSIONS. Although a high percentage of school-aged children are used to having breakfast, most have an incomplete breakfast. Very few manage to supplement their breakfast with snacks at mid-morning.

Improved high-frequency soft magnetic properties of FeCo films on organic ferroelectric PVDF substrate

Energy Technology Data Exchange (ETDEWEB)

Li, Dong; Wang, Zhen; Han, Xuemeng; Li, Yue; Guo, Xiaobin; Zuo, Yalu; Xi, Li, E-mail: xili@lzu.edu.cn

2015-02-01

FeCo films with various thicknesses were fabricated by direct-current magnetron sputtering on corning glass and organic ferroelectric PVDF substrates at the same time with 5 nm Ru seed layer and 5 nm Ta protective layer. The in-plane uniaxial anisotropy field of FeCo on glass substrate increases from 24 to 36 Oe with the increase of FeCo film thickness from 5 to 100 nm. However, a large in-plane anisotropy field of FeCo on PVDF substrate increases with FeCo thickness from 5 to 20 nm and gradually decreases with the FeCo thickness further increasing. Atomic force microscope images of FeCo on glass show quite smooth surface with root-mean-square roughness around 0.5 nm and have none visible granules on the surface for all samples. While, AFM images of FeCo on PVDF show quite rough surface with RMS roughness around 25 nm and have visible granules with the smallest granules appearing at the FeCo thickness of 20 nm. The permeability spectra show the typical ferromagnetic resonance phenomenon and can be well fitted by the LLG equation with the obtained experimental parameters. The ferromagnetic resonance frequency can reach 7.0 GHz for the 20 nm FeCo film on PVDF. Moreover, the quality factor of this sample can respectively reach 26, 12 and 7 at 1.0, 2.0, and 3.0 GHz, indicating the potential real 3G application for high-frequency devices. - Highlights: 1.Magnetic and morphological properties of FeCo films on PVDF substrates are studied. 2.The large anisotropy field of FeCo films on PVDF is obtained. 3.Improved high frequency properties of FeCo films on flexible substrates are obtained. 4.The origin of improved high frequency properties of FeCo films on PVDF is studied.

Room temperature luminescence and ferromagnetism of AlN:Fe

Directory of Open Access Journals (Sweden)

H. Li

2016-06-01

Full Text Available AlN:Fe polycrystalline powders were synthesized by a modified solid state reaction (MSSR method. Powder X-ray diffraction and transmission electron microscopy results reveal the single phase nature of the doped samples. In the doped AlN samples, Fe is in Fe2+ state. Room temperature ferromagnetic behavior is observed in AlN:Fe samples. Two photoluminescence peaks located at about 592 nm (2.09 eV and 598 nm (2.07 eV are observed in AlN:Fe samples. Our results suggest that AlN:Fe is a potential material for applications in spintronics and high power laser devices.

Interparticle interactions of FePt core and Fe{sub 3}O{sub 4} shell in FePt/Fe{sub 3}O{sub 4} magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Akbari, Hossein, E-mail: Akbari.ph@iauardabil.ac.ir [Department of Physics, Ardabil Branch, Islamic Azad University, Ardabil (Iran, Islamic Republic of); Zeynali, Hossein [Department of Physics, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Bakhshayeshi, Ali [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2016-02-22

Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. In FePt/Fe{sub 3}O{sub 4} core/shell system, core thickness is 2 nm and shell thickness varies from zero to 2.5 nm. A theoretical model presented to calculate the shell thickness dependence of Coercivity. Presented model is compared with the results from Stoner–Wohlfarth model to interpret the shell thickness dependence of Coercivity in FePt/Fe{sub 3}O{sub 4} core/shell nanoparticles. There is a difference between the results from Stoner–Wohlfarth model and experimental data when the shell thickness increases. In the presented model, the effects of interparticle exchange and random magneto crystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve a better agreement with experimental data. For magnetic shells in FePt/Fe{sub 3}O{sub 4} core/shell, effective coupling between particles increases with increasing shell thickness which leads to Coercivity destruction for stronger couplings. According to the boundary conditions, in the harder regions with higher exchange stiffness, there is small variation in magnetization and so the magnetization modes become more localized. We discussed both localized and non-localized magnetization modes. For non-zero shell thickness, non-localized modes propagate in the soft phase which effects the quality of particle exchange interactions. - Highlights: • Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. • Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. • A theoretical model presented to calculate the shell thickness dependence of Coercivity. • Magnetic shells increase effective coupling between particles with increasing shell thickness. • Magnetization modes are more localized in the regions with

Photoluminescence and doping mechanism of theranostic Eu3+/Fe3+ dual-doped hydroxyapatite nanoparticles

Science.gov (United States)

Chen, Min-Hua; Yoshioka, Tomohiko; Ikoma, Toshiyuki; Hanagata, Nobutaka; Lin, Feng-Huei; Tanaka, Junzo

2014-10-01

Theranostic nanoparticles currently have been regarded as an emerging concept of ‘personalized medicine’ with diagnostic and therapeutic dual-functions. Eu3+ doped hydroxyapatite (HAp) has been regarded as a promising fluorescent probe for in vivo imaging applications. Additionally, substitution of Ca2+ with Fe3+ in HAp crystal may endow the capability of producing heat upon exposure to a magnetic field. Here we report a preliminary study of doping mechanism and photoluminescence of Eu3+ and Fe3+ doped HAp nanoparticles (Eu/Fe:HAp). HAp with varied concentration of Eu3+ and Fe3+ doping are presented as Eu(10 mol%):HAp, Eu(7 mol%)-Fe(3 mol%):HAp, Eu(5 mol%)-Fe(5 mol%):HAp, Eu(3 mol%)-Fe(7 mol%):HAp, and Fe(10 mol%):HAp in the study. The results showed that the HAp particles, in nano-size with rod-like morphology, were successfully doped with Eu3+ and Fe3+, and the particles can be well suspended in cell culture medium. Photoluminescence analysis revealed that particles have prominent emissions at 536 nm, 590 nm, 615 nm, 650 nm and 695 nm upon excitation at a wavelength of 397 nm. Moreover, these Eu/Fe:HAp nanoparticles belonged to B-type carbonated HAp, which has been considered an effective biodegradable and biocompatible drug/gene carrier in biological applications.

Photoluminescence and doping mechanism of theranostic Eu3+/Fe3+ dual-doped hydroxyapatite nanoparticles

International Nuclear Information System (INIS)

Chen, Min-Hua; Lin, Feng-Huei; Yoshioka, Tomohiko; Ikoma, Toshiyuki; Tanaka, Junzo; Hanagata, Nobutaka

2014-01-01

Theranostic nanoparticles currently have been regarded as an emerging concept of ‘personalized medicine’ with diagnostic and therapeutic dual-functions. Eu 3+ doped hydroxyapatite (HAp) has been regarded as a promising fluorescent probe for in vivo imaging applications. Additionally, substitution of Ca 2+ with Fe 3+ in HAp crystal may endow the capability of producing heat upon exposure to a magnetic field. Here we report a preliminary study of doping mechanism and photoluminescence of Eu 3+ and Fe 3+ doped HAp nanoparticles (Eu/Fe:HAp). HAp with varied concentration of Eu 3+ and Fe 3+ doping are presented as Eu(10 mol%):HAp, Eu(7 mol%)-Fe(3 mol%):HAp, Eu(5 mol%)-Fe(5 mol%):HAp, Eu(3 mol%)-Fe(7 mol%):HAp, and Fe(10 mol%):HAp in the study. The results showed that the HAp particles, in nano-size with rod-like morphology, were successfully doped with Eu 3+ and Fe 3+ , and the particles can be well suspended in cell culture medium. Photoluminescence analysis revealed that particles have prominent emissions at 536 nm, 590 nm, 615 nm, 650 nm and 695 nm upon excitation at a wavelength of 397 nm. Moreover, these Eu/Fe:HAp nanoparticles belonged to B-type carbonated HAp, which has been considered an effective biodegradable and biocompatible drug/gene carrier in biological applications. (paper)

Photoluminescence and doping mechanism of theranostic Eu3+/Fe3+ dual-doped hydroxyapatite nanoparticles.

Science.gov (United States)

Chen, Min-Hua; Yoshioka, Tomohiko; Ikoma, Toshiyuki; Hanagata, Nobutaka; Lin, Feng-Huei; Tanaka, Junzo

2014-10-01

Theranostic nanoparticles currently have been regarded as an emerging concept of 'personalized medicine' with diagnostic and therapeutic dual-functions. Eu 3+ doped hydroxyapatite (HAp) has been regarded as a promising fluorescent probe for in vivo imaging applications. Additionally, substitution of Ca 2+ with Fe 3+ in HAp crystal may endow the capability of producing heat upon exposure to a magnetic field. Here we report a preliminary study of doping mechanism and photoluminescence of Eu 3+ and Fe 3+ doped HAp nanoparticles (Eu/Fe:HAp). HAp with varied concentration of Eu 3+ and Fe 3+ doping are presented as Eu(10 mol%):HAp, Eu(7 mol%)-Fe(3 mol%):HAp, Eu(5 mol%)-Fe(5 mol%):HAp, Eu(3 mol%)-Fe(7 mol%):HAp, and Fe(10 mol%):HAp in the study. The results showed that the HAp particles, in nano-size with rod-like morphology, were successfully doped with Eu 3+ and Fe 3+ , and the particles can be well suspended in cell culture medium. Photoluminescence analysis revealed that particles have prominent emissions at 536 nm, 590 nm, 615 nm, 650 nm and 695 nm upon excitation at a wavelength of 397 nm. Moreover, these Eu/Fe:HAp nanoparticles belonged to B-type carbonated HAp, which has been considered an effective biodegradable and biocompatible drug/gene carrier in biological applications.

Fabrication and magnetic properties of Fe/GaAs/Fe hybrid structures

OpenAIRE

Wong, P.K.J.; Zhang, W.; Zhang, W.; Wu, J.; Will, I.G.; Xu, Y.B.; Farrer, I.; Ritchie, D.A.

2010-01-01

In this contribution, experimental results on the fabrication and magnetic characterization of a novel type vertical Fe/GaAs(100)/Fe spin-valve (SV) spintronic device are presented. An array of techniques has been developed by combining use of ex-situ chemical and selective etching of GaAs/AlGaAs/n-GaAs epilayers and ultrahigh vacuum deposition of Fe by molecular beam epitaxy (MBE). The thinnest achievable GaAs membrane by these sequences can be as thin as 50 nm.

A Novel Ternary CoFe2O4/CuO/CoFe2O4 as a Giant Magnetoresistance Sensor

Directory of Open Access Journals (Sweden)

Ramli

2016-12-01

Full Text Available This paper reports the results of a study relating to the synthesis of a novel ternary CoFe2O4/CuO/CoFe2O4 thin film as a giant magnetoresistance (GMR sensor. The CoFe2O4/CuO/CoFe2O4 thin film was prepared onto silicon substrate via DC magnetron sputtering with the targets facing each other. X-ray diffraction was used to determine the structure of the thin film and a 4-point method was used to measure the MR ratio. The GMR ratio is highly dependent on the ferrimagnetic (CoFe2O4 and nonmagnetic (CuO layer thickness. The maximum GMR ratio at room temperature obtained in the CoFe2O4/CuO/CoFe2O4 thin film was 70% when the CoFe2O4 and the CuO layer had a thickness of 62.5 nm and 14.4 nm respectively.

Presencia de Hydrochoerus hydrochaeris (Hydrochoeridae, Rodentia, Mammalia en la cuenca del río Carcarañá, Santa Fe, Argentina: Comentarios acerca de su conservación y biogeografía en Argentina

Directory of Open Access Journals (Sweden)

Pablo G. Rimoldi

2014-01-01

Full Text Available El carpincho (Hydrochoerus hydrochaeris es el roedor actual más grande del mundo y uno de los mamíferos típico de las Provincias Fitogeográficas Pampeana y del Espinal, habitando todo el sector Este de las mismas. Estas regiones han sido categorizadas por la World Wildlife Foundation (WWF como áreas "en peligro crítico/ amenazada", y se les asigna el nivel de máxima prioridad de conservación como consecuencia de la destrucción de hábitat, la sobreexplotación, la contaminación y la introducción de especies exóticas. El carpincho presenta una preferencia marcada por los ambientes con abundancia de cuerpos de agua donde la vegetación palustre le proporciona alimento y refugio. De esta forma, tanto los cuerpos de agua como la vegetación asociada es determinante para la prevalescencia de poblaciones de carpinchos en un ambiente determinado. Para la provincia de Santa Fe los registros no son muy abundantes, registrándose hasta la actualidad unos 33 puntos de colecta/observación, la gran mayoría ubicados en el centro y norte de la provincia. El objetivo de la presente contribución es presentar nuevos registros de presencia de Hydrochoerus hydrochaeris en la cuenca del río Carcarañá (sur de la provincia de Santa Fe, y su asociación con algunas variables climático-ambientales y evaluar la distribución de esta especie. Finalmente, se discute la posible expansión o migración de este especie hacia el oeste de esta provincia y de la provincia de Buenos Aires.

DOE ZERH Case Study: Palo Duro Homes, Via del Cielo, Santa Fe, NM

Energy Technology Data Exchange (ETDEWEB)

none,

2015-09-01

Case study of a DOE 2015 Housing Innovation Award winning production home in the mixed-dry climate that got a HERS 48 without PV, with 2x6 24” on center walls with R-21 blown fiberglass; slab foundation with R-10 under slab and R-5rigid foam at slab edge; vented attic with R-75 blown fiberglass; ducted minisplit heat pump 16.5 SEER, 9.5 HSPF.

Santa Fe, NM 1:250,000 Quad USGS Land Use/Land Cover, 1986

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This dataset contains boundaries for land use and land cover polygons in New Mexico at a scale of 1:250,000. It is in a vector digital data structure. The source...

Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers

Energy Technology Data Exchange (ETDEWEB)

Bouziane, K.; Al-Busaidi, M.; Gismelseed, A.; Al-Rawas, A. [Physics Department, College of Science, Sultan Qabos University, P. O. Box 36, Postal Code 123, Al-Khodh, Muscat (Oman)

2004-05-01

Structural, magnetic and magneto-transport properties of thermally evaporated Fe/Cu multilayers (MLs) have been investigated. Although multilayered structure has been successfully obtained, a substantial interfacial roughness ranging from 0.6 nm to 1.2 nm has been determined. All Fe/Cu MLs were polycrystalline with an average grain size of about 10 nm. Fe was bcc and textured (110) whereas Cu was fcc(111). Transmission electron microscopy analysis showed that the fcc Cu layer was rather textured (110) and (100) at least in the first stage of growth of the Fe/Cu MLs. Conversion electron Moessbauer (CEMS) measurements indicated the existence of three phases. Two of them were magnetic with a dominant bcc Fe phase, followed by fcc Fe phase. The third phase was superparamagnetic. The CEMS results were explained in terms of the partial diffusion of Fe into Cu with three different zones. The small magnetoresistance (MR<0.2%) was correlated to Fe clusters located at Fe-Cu interfaces. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

Aspectos epidemiológicos del cáncer no melanoma de piel en un servicio de dermatología de la ciudad de Santa Fe - Argentina 2007 Epidemiologic aspects to the skin cancer non melanoma in a dermatologic office of the Santa Fe city - Argentine 2007

Directory of Open Access Journals (Sweden)

B L M Lukaszuk

2008-03-01

Full Text Available Antecedentes: la incidencia del cáncer no melanoma de piel (CNMP, principalmente en países tropicales ha aumentado en grandes proporciones. La identificación de lesiones sospechosas y aquellas relacionadas directamente con el cáncer de piel es efectuada en ocasiones por colegas de muchas especialidades médicas. Objetivos: estudiar las características de la frecuencia del CNMP en relación con ciertos factores de riesgo en el Hospital José María Cullen, de la ciudad de Santa Fe, capital de la provincia del mismo nombre, Argentina. Materiales y métodos: estudio retrospectivo, no experimental, descriptivo y de corte transversal. La muestra quedó conformada por 61 pacientes de ambos sexos y de 1 a 83 años. Se confeccionó una historia clínica completa de los pacientes candidatos a la toma de biopsia, que luego fue analizada por el Servicio de Anatomía Patológica. Se realizó un análisis descriptivo utilizando el programa SPSS 11.5, mediante el cual se usó la prueba de Chi cuadrado y tablas de contingencia para relacionar las variables y comparar los datos. Se estableció una asociación estadísticamente significativa cuando se halló un valor de pBackground: The incidence of non-melanoma skin cancer (NMSC, mainly in tropical countries has increased in large proportions. The identification of suspicious lesions and those directly related to the skin cancer is made by colleagues of many medical specialities. Objectives: Study the characteristics of the frequency of NMSC and their relation with certain risk factors in the Hospital José María Cullen, city of Santa Fe, capital of the province of the same name, Argentina. Materials and Methods: This was a retrospective, not experimental, descriptive and transversal cut study. The sample was composed by 61 patients of both sexs and from 1 to 83 years old. A complete clinical history of patients with suspected lesions were developed. After the biopsy collection, the Department of

Magnetic and microstructural properties of thin NdFeB based films and nanostructures

Energy Technology Data Exchange (ETDEWEB)

Bommer, Lars; Goll, Dagmar [Max-Planck-Institut fuer Metallforschung, Stuttgart (Germany)

2010-07-01

The magnetic and microstructural properties of NdFeB and NdFeB/Fe thin films and nanostructures are presented. Samples with Cr buffer and protection layer (minimum thickness: d=50 nm) have been produced by ion beam sputtering at elevated temperatures (T{sub s}=700 C) using Al{sub 2}O{sub 3} and MgO(001) single crystal substrates. Films deposited on Al{sub 2}O{sub 3} substrates show c-axis growth in out-of-plane direction down to thicknesses of the NdFeB film of d=10 nm with coercivities up to {mu}{sub 0}H{sub c}=1 T. The texture of films deposited on MgO(001) substrates is less pronounced and films below d=20 nm show no hard magnetic behavior. For comparison, films were deposited at room temperature on Al{sub 2}O{sub 3} and MgO(001) followed by post-annealing in Ar atmosphere (T{sub pa}=525-650 C) leading to coercivities as high as {mu}{sub 0}H{sub c}=1.2 T but with isotropic behavior. By TEM images the grain structure of the NdFeB samples is studied. Bilayers of NdFeB (d=50 nm) and Fe (d=0-20 nm) show fully exchange coupled behavior. From the temperature dependence of the coercivity the microstructural parameters of all samples have been determined. Furthermore NdFeB periodical patterns were produced by means of electron beam lithography with dot sizes of 1000 nm and 500 nm, respectively.

Growth and characterization of Fe nanostructures on GaN

International Nuclear Information System (INIS)

Honda, Yuya; Hayakawa, Satoko; Hasegawa, Shigehiko; Asahi, Hajime

2009-01-01

We have investigated the growth of Fe nanostructures on GaN(0 0 0 1) substrates at room temperature using reflection high-energy electron diffraction (RHEED), scanning tunneling microscopy (STM), and superconducting quantum interference device magnetometer. Initially, a ring RHEED pattern appears, indicating the growth of polycrystalline α-Fe. At around 0.5 nm deposition, the surface displays a transmission pattern from α-Fe films with the epitaxial relationship of Fe(1 1 0)//GaN(0 0 0 1) and Fe[1 -1 1]//GaN[1 1 -2 0] (Kurdjumov-Sachs (KS) orientational relationship). Further deposition to 1 nm results in the appearance of a new spot pattern together with the pattern from domains with the KS orientation relationship. The newly observed pattern shows that Fe layers are formed with the epitaxial relationship of Fe(1 1 0)//GaN(0 0 0 1) and Fe[0 0 1]//GaN[1 1 -2 0] (Nishiyama-Wasserman (NW) orientational relationship). From STM images for Fe layers with the KS and NW orientational relationships, it can be seen that Fe layers with the KS relationship consist of round-shaped Fe nanodots with below 7 nm in average diameter. These nanodots coalesce to form nanodots elongating along the Fe[1 0 0] direction, and they have the KS orientational relationship. Elongated Fe nanodots with the NW relationship show ferromagnetism while round-shaped Fe nanodots with the KS relationship show super-paramagnetic behavior. We will discuss their magnetic properties in connection with the change in crystalline configurations of nanodots.

Metal concentrations in demersal fish species from Santa Maria Bay, Baja California Sur, Mexico (Pacific coast).

Science.gov (United States)

Jonathan, M P; Aurioles-Gamboa, David; Villegas, Lorena Elizabeth Campos; Bohórquez-Herrera, Jimena; Hernández-Camacho, Claudia J; Sujitha, S B

2015-10-15

Concentrations of 11 trace metals (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd, As, Hg) in 40 fish species from Santa Maria Bay, Baja California Sur, Mexico, the strategically important area for marine mammals and organisms were analyzed. Based on their concentrations the ranking of metals Fe>Zn>Ni>Cr>Mn>Pb>Cu>Co>As>Cd>Hg suggests that organism size, metabolism and feeding habits are correlated with metal concentrations. Local geological formations affect the concentrations of different metals in the aquatic environment and are subsequently transferred to fishes. The correlation analysis suggests that metabolism and nurturing habits impact the concentration of metals. Concentrations of Fe and Mn appear to be influenced by scavenging and absorption processes, which vary by species. The considerable variability in the metal concentrations obtained in different species underscores the importance of regular monitoring. Copyright © 2015 Elsevier Ltd. All rights reserved.

Observation of high coercive fields in chemically synthesized coated Fe-Pt nanostructures

Energy Technology Data Exchange (ETDEWEB)

Dalavi, Shankar B.; Panda, Rabi N., E-mail: rnp@goa.bits-pilani.ac.in

2017-04-15

Nanocrystalline Fe-Pt alloys have been synthesized via chemical reduction route using various capping agents; such as: oleic acid/oleylamine (route-1) and oleic acid/CTAB (route-2). We could able to synthesize Fe50Pt and Fe54Pt alloys via route 1 and 2, respectively. As-prepared Fe-Pt alloys crystallize in disordered fcc phase with crystallite sizes of 2.3 nm and 6 nm for route-1 and route-2, respectively. Disordered Fe-Pt alloys were transformed to ordered fct phase after annealing at 600 °C. SEM studies confirm the spherical shape morphologies of annealed Fe-Pt nanoparticles with SEM particle sizes of 24.4 nm and 21.2 nm for route-1 and route-2, respectively. TEM study confirms the presence of 4.6 nm particles for annealed Fe50Pt alloys with several agglomerating clusters of bigger size and appropriately agrees well with the XRD study. Room temperature magnetization studies of as-prepared Fe-Pt alloys (fcc) show ferromagnetism with negligible coercivities. Average magnetic moments per particle for as-prepared Fe-Pt alloys were estimated to be 753 μ{sub B} and 814 μ{sub B}, for route 1 and 2, respectively. Ordered fct Fe-Pt alloys show high values of coercivities of 10,000 Oe and 10,792 Oe for route-1 and route-2, respectively. Observed magnetic properties of the fct Fe-Pt alloys nps were interpreted with the basis of order parameters, size, surface, and composition effects. - Highlights: • Synthesis of capped nanocrystalline Fe-Pt alloys via chemical routes. • Ordered fct phase were obtained at 600 °C. • Microstructural studies were carried out using SEM and TEM. • Investigation on evolution of magnetic properties from fcc to fct state. • Maximum values of coercivities up to 10,792 Oe were observed.

Summary: Electron-cloud effects and fast-ion instability

International Nuclear Information System (INIS)

Furman, Miguel A.

2000-01-01

This is my summary of the talks on the electron-cloud effect and the fast-ion instability that were presented at the 8th ICFA Beam Dynamics Mini-Work shop on Two-Stream Instabilities in Particle Accelerators and Storage Rings,Santa Fe, NM, February 16--18, 2000

Uniformed Services Worldwide Legal Assistance & Reserve Components Office Directory. Revised.

Science.gov (United States)

1999-11-01

257-1829 Commander (dl) 14th Coast Guard District Prince Kalanianaole Federal Building 300 Ala Moana Blvd, 9th Floor Honolulu, Hawaii 96850-4982...a),aarons.org Practice Area: 351 - Criminal Law - Defense, 400 - General Practice Bars Admitted: NM County of Practice: Santa Fe, Rio Arriba , Los

Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. 'Santa Maria' in semi-arid conditions

Directory of Open Access Journals (Sweden)

Ali Ikinci

2014-01-01

Full Text Available BACKGROUND: Rootstocks play an essential role to determining orchard performance of fruit trees. Pyrus communisand Cydonia oblonga are widely used rootstocks for European pear cultivars. The lack of rootstocks adapted to different soil conditions and different grafted cultivars is widely acknowledged in pear culture. Cydonia rootstocks (clonal and Pyrus rootstocks (seedling or clonal have their advantages and disadvantages. In each case, site-specific environmental characteristics, specific cultivar response and production objectives must be considered before choosing the best rootstock. In this study, the influence of three Quince (BA 29, Quince A = MA, Quince C = MC and a local European pear seedling rootstocks on the scion yield, some fruit quality characteristics and leaf macro (N, P, K, Ca and Mg and micro element (Fe, Zn, Cu, Mn and B content of 'Santa Maria' pear (Pyrus communis L. were investigated. RESULTS: Trees on seedling rootstock had the highest annual yield, highest cumulative yield (kg tree−1, largest trunk cross-sectional area (TCSA, lowest yield efficiency and lowest cumulative yield (ton ha−1 in the 10th year after planting. The rootstocks had no significant effect on average fruit weight and fruit volume. Significantly higher fruit firmness was obtained on BA 29 and Quince A. The effect of rootstocks on the mineral element accumulation (N, K, Ca, Mg, Fe, Zn, Cu, Mn and B was significant. Leaf analysis showed that rootstocks used had different mineral uptake efficiencies throughout the early season. CONCLUSION: The results showed that the rootstocks strongly affected fruit yield, fruit quality and leaf mineral element uptake of 'Santa Maria' pear cultivar. Pear seedling and BA 29 rootstock found to be more prominent in terms of several characteristics for 'Santa Maria' pear cultivar that is grown in highly calcareous soil in semi-arid climate conditions. We determined the highest N, P (although insignificant, K, Ca, Mg, Fe

1D Magnetic Materials of Fe3O4 and Fe with High Performance of Microwave Absorption Fabricated by Electrospinning Method

Science.gov (United States)

Han, Rui; Li, Wei; Pan, Weiwei; Zhu, Minggang; Zhou, Dong; Li, Fa-shen

2014-01-01

Fe3O4 and Fe nanowires are successfully fabricated by electrospinning method and reduction process. Wiry microstructures were achieved with the phase transformation from α-Fe2O3 to Fe3O4 and Fe by partial and full reduction, while still preserving the wire morphology. The diameters of the Fe3O4 and Fe nanowires are approximately 50–60 nm and 30–40 nm, respectively. The investigation of microwave absorption reveals that the Fe3O4 nanowires exhibit excellent microwave absorbing properties. For paraffin-based composite containing 50% weight concentration of Fe3O4 nanowires, the minimum reflection loss reaches −17.2 dB at 6.2 GHz with the matching thickness of 5.5 mm. Furthermore, the calculation shows that the modulus of the ratio between the complex permittivity and permeability |ε/μ| is far away from unity at the minimum reflection loss point, which is quite different from the traditional opinions. PMID:25510415

Synthesis and characterization of magnetic Fe/CNTs composites with controllable Fe nanoparticle concentration

International Nuclear Information System (INIS)

Zhao Fan; Duan Hongyan; Wang Weigao; Wang Jun

2012-01-01

Fe/CNTs composites, with different concentrations of Fe nanoparticles (NPs) on carbon nanotube (CNT) surfaces, were successfully fabricated via a facile solvothermal method. The lengths of CNTs are up to 10 μm and the mean diameter of the Fe nanoparticles is about 25 nm. The structures, composition and magnetic properties of the Fe/CNTs were characterized by XRD, FTIR, FE-SEM, TEM and PPMS. We found that the concentrations of Fe nanoparticles depositing on the CNTs could be controlled by adjusting the initial mass ratio of ferrocene to CNTs. The Fe/CNTs composites display good ferromagnetic properties at room temperature, with a saturation magnetization of 125 emu/g-Fe and a coercivity of 276 Oe. The Curie temperature of the sample is about 1038 K, slightly lower than that (1043 K) of the bulk iron.

Amorphous Fe-B alloys in B-Fe-Ag multilayers studied by magnetization and Mössbauer measurements

DEFF Research Database (Denmark)

Kiss, L. F.; Balogh, J.; Bujdoso, L.

2011-01-01

Bulk and local magnetic properties were studied in [1 nm B + 1 nm 57Fe + x nm Ag]5, x = 1, 2, 4, 5 and 10, multilayer samples. Although Ag does not mix with either of the other two elements the magnetic properties of the multilayers are strongly influenced by the Ag thickness below x = 5, whereas...

Preparation and properties of [(NdFeB)x/(Nb)z]n multi-layer films

International Nuclear Information System (INIS)

Tsai, J.-L.; Chin, T.-S.; Yao, Y.-D.; Melsheimer, A.; Fisher, S.; Drogen, T.; Kelsch, M.; Kronmueller, H.

2003-01-01

Multi-layer [(NdFeB) x /(Nb) z ] n films with 200 nm≥x≥10 nm, 10 nm≥z≥0, 40≥n≥2, prepared by ion beam sputtering and subsequent annealing, show significantly enhanced coercivity due to the reduced grain size that enhances the anisotropy of individual grains. After annealing at 630 deg. C, some Nd 2 Fe 14 B grains were enriched with Nb and isolated as the thickness of the Nb spacer layer increases. For multi-layer (NdFeB x /Nb z ) n films with 100 nm ≥x≥25 nm, 5 nm≥z≥2 nm, their coercivity and remanence ratio are better than that of a single NdFeB film. Up to 17.8 kOe room temperature coercivity has been obtained for a sample with x=25 nm, z=5 nm and n=16

A study on the microstructural characteristics of rapidly solidified Al-Fe alloys(I)

International Nuclear Information System (INIS)

Kim, D.H.; Lee, H.I.

1991-01-01

Solidification microstructures and phases in rapidly solidified Al-5, 10wt% Fe alloys have been investigated by TEM bright field and dark field imaging techniques and electron and x-ray diffraction techniques. Rapid solidification of Al-5, 10wt%Fe alloys produces various metastable and stable phases, such as Al m Fe, Al 6 Fe and Al 13 Fe 4 . In addition to these phases, clusters of randomly oriented few nm scale particles exist in the form of fine cellular network with α-Al or primary spherical particles. Solidification microstructures of the rapidly solidified Al-5, 10wt%Fe alloys consist of various combination of primary phases such as Al 13 Fe 4 , Al m Fe and cluster of nm scale particles, and cellular/dendritic structures such as fine cellular network structure of nm scale particle clusters and α-Al and cellular structure of Al m Fe and α-Al, depending upon alloy compositions and local cooling rates. (Author)

Rapid thermal annealing of FePt and FePt/Cu thin films

Energy Technology Data Exchange (ETDEWEB)

Brombacher, Christoph

2011-01-10

Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

Macroeconomia do Turismo Argentino em Santa Catarina

Directory of Open Access Journals (Sweden)

Roberto Meurer

2010-07-01

Full Text Available Resumo O Estado de Santa Catarina experimentou um considerável crescimento do setor de turismo nas últimas décadas. O fluxo turístico de origem argentina revelou-se um ingrediente importante dessa trajetória. Este artigo focaliza um aspecto pouco explorado, aparentemente, da participação argentina no turismo estadual: a relação entre a situação macroeconômica do país vizinho e a demanda turística por Santa Catarina lá originada. Começa-se abordando brevemente a problemática geral da macroeconomia do turismo. Depois, discorre-se sobre o crescimento desse setor em Santa Catarina, destacando a presença de argentinos. A terceira parte desenvolve uma análise baseada em tratamento estatístico de dados sobre demanda e receita geradas por esses turistas no estado, com exame das correlações envolvendo taxa de câmbio e taxa de crescimento do PIB da Argentina. Palavras-chave: turismo; Santa Catarina; turistas argentinos; economia argentina Abstract The State of Santa Catarina has witnessed a considerable development of its tourist sector in the last decades. The demand from Argentina has proved to be an important factor of that growth. This article deals with a feature of the presence of Argentinians in the state which seems to be scarcely studied: the relationship between the macroeconomic situation of Argentina and the tourist demand in Santa Catarina originated from that country. The first part of the article considers briefly the general issue of tourism macroeconomics. The second one looks upon tourism growth in Santa Catarina, stressing the presence of visitors from Argentine. The third section develops an analysis based on statistical treatment of data concerning demand and income generated by such tourists in Santa Catarina, involving correlations that consider aspects like exchange rate and the rate of GDP increase in Argentina. Keywords: tourism; Santa Catarina; tourists from Argentina; Argentina’s economy

Harold A. Hyde: Recollections of Santa Cruz County

OpenAIRE

Hyde, Harold A.; Jarrell, Randall; Regional History Project, UCSC Library

2002-01-01

A fifth-generation Santa Cruz County resident, Hyde has been in on the creation of organizations and institutions ranging from UCSC and Cabrillo College to the Community Foundation and the Cultural Council of Santa Cruz County. His contributions to California and Santa Cruz are documented in his oral history. Following infantry combat service with the U.S. Army in Europe during World War II and graduate studies in business at Harvard, Hyde returned to Santa Cruz County and a career a...

New stable phase in binary Fe-Nd

International Nuclear Information System (INIS)

Schneider, G.; Landgraf, F.J.G.; Villas-Boas, V.; Bezerra, G.H.; Missell, F.P.; Ray, A.E.

1992-01-01

An investigation of binary Fe-Nd alloys revealed the existence of an oxygen-free, stable Fe-rich phase A 2 , formed peritecticly in the range 750-800 deg C. EPMA shows this phase to contain 22.8 atomic percent Nd. This ferromagnetic phase has T c = 230 de C, but is magnetically soft. The X-ray diffraction pattern can be indexed using a hexagonal cell with a = 2.021 nm. and c = 1.235 nm. (author)

Calidad de los suelos del norte de Santa Fe: Efecto de la geomorfología y uso de la tierra Soil quality in the north of Santa Fe: Effect of geomorphology and land use

Directory of Open Access Journals (Sweden)

Olga Susana Heredia

2006-12-01

Full Text Available En el norte de la provincia de Santa Fe existen escasos trabajos a escala detallada de las propiedades del suelo, cuyo conocimiento es importante a la hora de tomar decisiones para el uso más adecuado del mismo a nivel predial. En este trabajo se plantea como objetivo analizar el efecto de la geomorfología y el uso de la tierra sobre las propiedades físicoquímicas en suelos de la cuña boscosa santafesina. Se evaluaron los tipos de suelos presentes en distintos ambientes geomorfológicos, se clasificaron taxonómicamente, y se analizaron: textura, carbono oxidable (Cox, fósforo extractable (Pe, reacción del suelo (pH y conductividad eléctrica (CE. Las situaciones analizadas fueron: pastizal natural (Ai; chacra nueva, 2 años de uso agrícola (Ch2; chacra vieja, 20 años de uso agrícola (Ch20; monte (M; quebrachal (Qu y espartillar (Es. Se realizó un ANVA entre las distintas situaciones. Los suelos son Argiudoles típicos, Albacualfes y Epiacualfes, con diferente contenido de arcilla, pH y CE. Al comparar los suelos por su posición en le paisaje, todos se caracterizan por poseer texturas finas, con síntomas de hidromorfismo a distintas profundidades del perfil, bajo contenido de Pe a excepción del monte y pH moderadamente ácido a neutro en superficie alcalinizándose en profundidad, y se diferencian en el espesor del horizonte superficial y en el contenido de sales. Los suelos de posiciones del paisaje positivas (monte se encuentran más desarrollados y si bien son en general de textura fina, presentan menor contenido de arcillas que los de posiciones negativas del paisaje, como el quebrachal y el espartillar. El uso agrícola disminuye los valores de Cox y pH en el corto plazo y solo en el largo plazo disminuye el Pe. El Cox disminuyó 29,1% en la situación Ch2 y 46,7% en la situación Ch20 con respecto a la Ai. Los suelos son deficientes en Pe y su disminución fue de un 35,9% en la situación de mayor uso, sin presentar

Interplay between out-of-plane anisotropic L1{sub 1}-type CoPt and in-plane anisotropic NiFe layers in CoPt/NiFe exchange springs

Energy Technology Data Exchange (ETDEWEB)

Saravanan, P. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Defence Metallurgical Research Laboratory, Hyderabad 500058 (India); Hsu, Jen-Hwa, E-mail: jhhsu@phys.ntu.edu.tw; Tsai, C. L. [Department of Physics, National Taiwan University, Taipei 106, Taiwan (China); Tsai, C. Y.; Lin, Y. H. [Graduate Institute of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan (China); Kuo, C. Y.; Wu, J.-C. [Department of Physics, National Chang Hua University of Education, Chang Hua 50000, Taiwan (China); Lee, C.-M. [Graduate School of Materials Science, National Yunlin University of Science and Technology, Douliou 64002, Taiwan (China)

2014-06-28

Films of L1{sub 1}-type CoPt/NiFe exchange springs were grown with different NiFe (Permalloy) layer thickness (t{sub NiFe} = 0–10 nm). X-ray diffraction analysis reveals that the characteristic peak position of NiFe(111) is not affected by the CoPt-layer—confirming the absence of any inter-diffusion between the CoPt and NiFe layers. Magnetic studies indicate that the magnetization orientation of NiFe layer can be tuned through varying t{sub NiFe} and the perpendicular magnetic anisotropy of L1{sub 1}-type CoPt/NiFe films cannot sustain for t{sub NiFe} larger than 3.0 nm due to the existence of exchange interaction at the interface of L1{sub 1}-CoPt and NiFe layers. Magnetic force microscopy analysis on the as-grown samples shows the changes in morphology from maze-like domains with good contrast to hazy domains when t{sub NiFe} ≥ 3.0 nm. The three-dimensional micro-magnetic simulation results demonstrate that the magnetization orientation in NiFe layer is not uniform, which continuously increases from the interface to the top of NiFe layer. Furthermore, the tilt angle of the topmost NiFe layers can be changed over a very wide range from a small number to about 75° by varying t{sub NiFe} from 1 to 10 nm. It is worth noting that there is an abrupt change in the magnetization direction at the interface, for all the t{sub NiFe} investigated. The results of present study demonstrate that the tunable tilted exchange springs can be realized with L1{sub 1}-type CoPt/NiFe bilayers for future applications in three-axis magnetic sensors or advanced spintronic devices demanding inclined magnetic anisotropy.

Diversidad y aspectos biológicos de abejas silvestres de un ambiente urbano y otro natural de la región central de Santa Fe, Argentina Diversity and biological aspects of wild bees in an urban and a natural environment in the central region of Santa Fe, Argentina

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Milagros Dalmazzo

2010-06-01

Full Text Available El objetivo del presente trabajo fue relevar el elenco de abejas silvestres en la región central de Santa Fe y comparar la diversidad de especies y aspectos biológicos en dos ambientes de una misma región. Las abejas fueron colectadas en el estrato herbáceo de la Reserva Universitaria "Escuela Granja" de la localidad Esperanza, y en la zona urbana de la localidad Susana, ambas ubicadas dentro de la Provincia Fitogeográfica del Espinal. La colecta se realizó en octubre, noviembre y diciembre de 2004 y en enero, febrero y marzo de 2005, registrando las especies vegetales sobre las que se capturaron. Se colectaron 277 ejemplares en total, de los cuales se identificaron 62 especies (27 géneros en 5 familias. Las curvas de rarefacción indican una tasa de acumulación de especies mayor para la Reserva Ecológica, los índices de diversidad de Shannon son 3,25 para la Reserva Ecológica y 2,64 para la Zona Urbana. Para la comparación de las comunidades en ambos sitios, las abejas fueron clasificadas en tres categorías según la especialización en el uso del recurso floral, sustrato de nidificación y comportamiento social. Se observó una asociación entre los grupos especialistas y de nidificación en el suelo con el ambiente natural, y por otro lado, las especies generalistas y de nidificación en cavidades con el ambiente urbano. No se identificaron diferencias, en cuanto a la sociabilidad de las especies, entre ambos sitios.The purpose of this contribution is to present a survey of wild bees in the central region of Santa Fe, and to compare the diversity and biological aspects of the bee communities at two different environments of the same region. Bees were surveyed at the ecological reserve Reserva Universitaria "Escuela Granja" in the locality of Esperanza, and at an urban area in the locality of Susana, both in the Espinal Phytogeographic Province. Bees were sampled from October to December 2004 and from January to March 2005

77 FR 68827 - Notice of Intent To Repatriate Cultural Items: The Museum of Indian Arts and Culture, Museum of...

Science.gov (United States)

2012-11-16

... Intent To Repatriate Cultural Items: The Museum of Indian Arts and Culture, Museum of New Mexico, Santa Fe, NM AGENCY: National Park Service, Interior. ACTION: Notice. SUMMARY: The Museum of Indian Arts... Museum of Indian Arts and Culture. DATES: Representatives of any Indian tribe that believes it has a...

Molecular magnetism of a linear Fe(III)-Mn(II)-Fe(III) complex. Influence of long-range exchange interaction

International Nuclear Information System (INIS)

Lengen, M.; Chaudhuri, P.

1994-01-01

The magnetic properties of [L-Fe(III)-dmg 3 Mn(II)-Fe(III)-L] (ClO 4 ) 2 have been characterized by magnetic susceptibility, EPR, and Moessbauer studies. L represents 1,4,7-trimethyl-,1,4,7-triazacyclononane and dmg represents dimethylglyoxime. X-ray diffraction measurements yield that the arrangement of the three metal centers is strictly linear with atomic distances d Fe-Mn 0.35 nm and d Fe-Fe = 0.7 nm. Magnetic susceptibility measurements (3-295 K) were analyzed in the framework of the spin-Hamiltonian formalism considering Heisenberg exchange and Zeeman interaction: H = J Fe-Mn (S Fe1 + S Fe2 )S Mn + J Fe-Fe S Fe1 S Fe2 + gμ B S total B. The spins S Fe1 = S Fe2 = S Mn = 5/2 of the complex are antiferromagnetically coupled, yielding a total spin of S total = 5/2 with exchange coupling constants F Fe-Mn = 13.4 cm -1 and J Fe-Fe = 4.5 cm -1 . Magnetically split Moessbauer spectra were recorded at 1.5 K under various applied fields (20 mT, 170 mT, 4 T). The spin-Hamiltonian analysis of these spectra yields isotropic magnetic hyperfine coupling with A total /(g N μ N ) = -18.5 T. The corresponding local component A Fe is related to A total via spin-projection: A total = (6/7)A Fe . The resulting A Fe /(g N μ N ) -21.6 T is in agreement with standard values of ferric high-spin complexes. Spin-Hamiltonian parameters as obtained from Moessbauer studies and exchange coupling constants as derived from susceptibility measurements are corroborated by temperature-dependent EPR studies. (orig.)

Spacer layer effect and microstructure on multi-layer [NdFeB/Nb]n films

International Nuclear Information System (INIS)

Tsai, J.-L.; Yao, Y.-D.; Chin, T.-S.; Kronmueller, H.

2002-01-01

Spacer layer effect on multi-layer [NdFeB/Nb] n films has been investigated from the variation of magnetic properties and microstructure of the films. From a HRTEM cross-section view observation, the average grain size of [NdFeB/Nb] n multi-layers was controlled by both annealing temperature and thickness of NdFeB layer. Selected area diffraction pattern indicated that the structure of Nb spacer layer was amorphous. The grain size and coercivity of [NdFeB x /Nb] n films change from 50 nm and 16.7 kOe to 167 nm and 9 kOe for films with x=40 nm, n=10 and x=200 nm, n=2, respectively

Sub-10 nm Fe3O4@Cu2-xS core-shell nanoparticles for dual-modal imaging and photothermal therapy

KAUST Repository

Tian, Qiwei

2013-06-12

Photothermal nanomaterials have recently attracted significant research interest due to their potential applications in biological imaging and therapeutics. However, the development of small-sized photothermal nanomaterials with high thermal stability remains a formidable challenge. Here, we report the rational design and synthesis of ultrasmall (<10 nm) Fe3O 4@Cu2-xS core-shell nanoparticles, which offer both high photothermal stability and superparamagnetic properties. Specifically, these core-shell nanoparticles have proven effective as probes for T 2-weighted magnetic resonance imaging and infrared thermal imaging because of their strong absorption at the near-infrared region centered around 960 nm. Importantly, the photothermal effect of the nanoparticles can be precisely controlled by varying the Cu content in the core-shell structure. Furthermore, we demonstrate in vitro and in vivo photothermal ablation of cancer cells using these multifunctional nanoparticles. The results should provide improved understanding of synergistic effect resulting from the integration of magnetism with photothermal phenomenon, important for developing multimode nanoparticle probes for biomedical applications. © 2013 American Chemical Society.

Sub-10 nm Fe3O4@Cu2-xS core-shell nanoparticles for dual-modal imaging and photothermal therapy

KAUST Repository

Tian, Qiwei; Hu, Junqing; Zhu, Yihan; Zou, Rujia; Chen, Zhigang; Yang, Shiping; Li, Runwei; Su, Qianqian; Han, Yu; Liu, Xiaogang

2013-01-01

Photothermal nanomaterials have recently attracted significant research interest due to their potential applications in biological imaging and therapeutics. However, the development of small-sized photothermal nanomaterials with high thermal stability remains a formidable challenge. Here, we report the rational design and synthesis of ultrasmall (<10 nm) Fe3O 4@Cu2-xS core-shell nanoparticles, which offer both high photothermal stability and superparamagnetic properties. Specifically, these core-shell nanoparticles have proven effective as probes for T 2-weighted magnetic resonance imaging and infrared thermal imaging because of their strong absorption at the near-infrared region centered around 960 nm. Importantly, the photothermal effect of the nanoparticles can be precisely controlled by varying the Cu content in the core-shell structure. Furthermore, we demonstrate in vitro and in vivo photothermal ablation of cancer cells using these multifunctional nanoparticles. The results should provide improved understanding of synergistic effect resulting from the integration of magnetism with photothermal phenomenon, important for developing multimode nanoparticle probes for biomedical applications. © 2013 American Chemical Society.

Electronic structures and magnetism of CaFeAsH and CaFeAsF

International Nuclear Information System (INIS)

Wang Guangtao; Shi Xianbiao; Liu Haipeng; Liu Qingbo

2015-01-01

We studied the electronic structures, magnetism, and Fermi surface (FS) nesting of CaFeAsH and CaFeAsF by first-principles calculations. In the nonmagnetic (NM) states, we found strong FS nesting, which induces magnetic instability and a spin density wave (SDW). Our calculations indicate that the ground state of CaFeAsH and CaFeAsF is the stripe antiferromagnetic state. The calculated bare susceptibility χ 0 (q) peaked at the M-point and was clearly suppressed and became slightly incommensurate with both electron doping and hole doping for both materials. (author)

Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink-Rise system, north Florida, USA

Science.gov (United States)

Jin, Jin; Zimmerman, Andrew R.; Moore, Paul J.; Martin, Jonathan B.

2014-03-01

Spatiotemporal variations in dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major ions concentrations and other geochemical parameters including stable carbon isotopes of DIC (δ13CDIC), were measured in surface water and deep and shallow well water samples of the Santa Fe River Sink-Rise eogenetic karst system, north Florida, USA. Three end-member water sources were identified: one DOC-rich/DIC-poor/δ13CDIC-depleted, one DOC-poor/DIC-rich/δ13CDIC-enriched, and one enriched in major ions. Given their spatiotemporal distributions, they were presumed to represent soil water, upper aquifer groundwater, and deep aquifer water sources, respectively. Using assumed ratios of Na+, Cl, and SO42- for each end-member, a mixing model calculated the contribution of each water source to each sample. Then, chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations. In general, carbonate mineral dissolution occurred throughout the Sink-Rise system, surface waters were net autotrophic and the subsurface was in metabolic balance, i.e., no net DOC or DIC production or consumption. However, there was evidence for chemolithoautotrophy, perhaps by hydrogen oxidizing microbes, at some deep aquifer sites. Mineralization of this autochthonous natural dissolved organic matter (NDOM) led to localized carbonate dissolution as did surface water-derived NDOM supplied to shallow well sites during the highest flow periods. This study demonstrates linkages between hydrology, abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality, karst morphologic evolution, and hydrogeologic projects such as aquifer storage and recovery in karst systems.

L1{sub 0}-FePt films fabricated by wet-chemical route

Energy Technology Data Exchange (ETDEWEB)

Hong, Xiaoliang; Xiao, Wen; Bao, Nina; Li, Weimin; Chichvarina, Olga, E-mail: A0077107@nus.edu.sg; Ding, Jun, E-mail: msedingj@nus.edu.sg

2015-08-31

In this work, we have developed a method to fabricate FePt films by a combination of chemical deposition and post-annealing. Pt-doped Fe films were deposited on Pt(100 nm)/Ti(50 nm)/SiO{sub 2}/Si substrate using thermal deposition and the as-deposited films were subsequently annealed from 300 °C to 800 °C under 5% H{sub 2}/95% N{sub 2}. FePt films were achieved through diffusion and rearrangement of Fe and Pt atoms in post-annealing process. From X-ray diffraction results, the face-centered cubic (fcc) FePt phase appeared at 300 °C and the transformation from fcc to L1{sub 0} phase started at 400 °C. The L1{sub 0}-FePt film possessed an out-of-plane anisotropy and a coercivity of 729 kA/m after annealing at 600 °C. A further increase in annealing temperature led to lower value of coercivity, probably because of grain growth. In addition, the thickness of Pt-doped Fe films could be controlled from 150 nm to 700 nm by adjusting the amount of surfactant used. Our superconducting quantum interference device analysis showed that Pt dopant could significantly improve the chemical stability of Fe films in air. - Highlights: • We fabricated FePt film by a combination of chemical deposition and post-annealing. • L1{sub 0} FePt film was formed by Fe/Pt diffusion in annealing of Pt-doped Fe film. • L1{sub 0}-phase FePt with high coercivity and small out-of-plane anisotropy • Relatively small amount of Pt dopant can enhance chemical stability greatly. • We studied structure and magnetic property of as-deposited and annealed FePt film.

Resenha do livro: 'The Revolutions of 1893 in the Province of Santa F e Argentina'

Directory of Open Access Journals (Sweden)

Antônio E. Muniz Barreto

1977-03-01

Full Text Available (primeiro parágrafo do texto Ezequiel Gallo, conhecido historiador argentino, diretor do Instituto Torcuato Di Tella, assíduo colaborador da revista Desarrollo Economico e antigo membro do Instituto de Estudos Latino-Americanos da Universidade de Londres, acrescentou nesta monografia mais uma pesquisa, publicada na Inglaterra pelo Instituto acima mencionado, sobre a história de seu país. O estudo é desenvolvido a partir da sua tese de Doutor, Agricultural Colonization and Society in Argentina. The Province of Santa Fe, 1870-1895, apresentada em Oxford em 1970.

Magnetic properties and microstructure study of high coercivity Au/FePt/Au trilayer thin films

International Nuclear Information System (INIS)

Chen, S.K.; Yuan, F.T.; Liao, W.M.; Hsu, C.W.; Horng, Lance

2006-01-01

High-coercivity Au(60 nm)/FePt(δ nm)/Au(60 nm) trilayer samples were prepared by sputtering at room temperature, followed by post annealing at different temperatures. For the sample with δ=60 nm, L1 ordering transformation occurs at 500 deg. C. Coercivity (H c ) is increased with the annealing temperature in the studied range 400-800 deg. C. The H c value of the trilayer films is also varied with thickness of FePt intermediate layer (δ), from 27 kOe for δ=60 nm to a maximum value of 33.5 kOe for δ=20 nm. X-ray diffraction data indicate that the diffusion of Au atoms into the FePt L1 lattice is negligible even after a high-temperature (800 deg. C) annealing process. Furthermore, ordering parameter is almost unchanged as δ is reduced from 60 to 15 nm. Transmission electron microscope (TEM) photos indicate that small FePt Ll particles are dispersed amid the large-grained Au. We believe that the high coercivity of the trilayer sample is attributed to the small and uniform grain sizes of the highly ordered FePt particles which have perfect phase separation with Au matrix

Green rusts synthesis by coprecipitation of Fe II-Fe III ions and mass-balance diagram

Science.gov (United States)

Ruby, Christian; Aïssa, Rabha; Géhin, Antoine; Cortot, Jérôme; Abdelmoula, Mustapha; Génin, Jean-Marie

2006-06-01

A basic solution is progressively added to various mixed Fe II-Fe III solutions. The nature and the relative quantities of the compounds that form can be visualised in a mass-balance diagram. The formation of hydroxysulphate green rust {GR( SO42-)} is preceded by the precipitation of a sulphated ferric basic salt that transforms in a badly ordered ferric oxyhydroxide. Then octahedrally coordinated Fe II species and SO42- anions are adsorbed on the FeOOH surface and GR( SO42-) is formed at the solid/solution interface. By using the same method of preparation, other types of green rust were synthesised, e.g. hydroxycarbonate green rust {GR( CO32-)}. Like other layered double hydroxides, green rusts obey the general chemical formula [ṡ[ṡmHO]x+ with x⩽1/3. Al-substituted hydroxysulphate green rust consists of small hexagonal crystals with a lateral size ˜50 nm, which is significantly smaller than the size of the GR( SO42-) crystals (˜500 nm). To cite this article: C. Ruby et al., C. R. Geoscience 338 (2006).

Strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy

International Nuclear Information System (INIS)

Shi, Guodong; Chen, Xiaohua; Jiang, Han; Wang, Zidong; Tang, Hao; Fan, Yongquan

2015-01-01

A single crystal Cu–Fe alloy with finely dispersed precipitate Fe nanoparticles was fabricated in this study. The interface relationship of iron nanoparticle and copper matrix was analyzed with a high-resolution transmission electron microscope (HRTEM), and the effect of Fe nanoparticles on mechanical properties of single crystal Cu–Fe alloy was discussed. Results show that, the finely dispersed Fe nanoparticles can be obtained under the directional solidification condition, with the size of 5–50 nm and the coherent interface between the iron nanoparticle and the copper matrix. Single crystal Cu–Fe alloy possesses improved tensile strength of 194.64 MPa, and total elongation of 44.72%, respectively, at room temperature, in contrast to pure Cu sample. Nanoparticles which have coherent interface with matrix can improve the dislocation motion state. Some dislocations can slip through the nanoparticle along the coherent interface and some dislocations can enter into the nanoparticles. Thus to improve the tensile strength of single crystal Cu–Fe alloy without sacrificing the ductility simultaneously. Based on the above analyses, strengthening mechanisms of Fe nanoparticles for single crystal Cu–Fe alloy was described

Perpendicularly magnetized CoFeB multilayers with tunable interlayer exchange for synthetic ferrimagnets

Energy Technology Data Exchange (ETDEWEB)

Pirro, P., E-mail: ppirro@physik.uni-kl.de [Institut Jean Lamour, Université de Lorraine, UMR 7198 CNRS, 54506 Vandoeuvre-lés-Nancy (France); Hamadeh, A.; Lavanant-Jambert, M. [Institut Jean Lamour, Université de Lorraine, UMR 7198 CNRS, 54506 Vandoeuvre-lés-Nancy (France); Meyer, T. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany); Tao, B.; Rosario, E.; Lu, Y.; Hehn, M.; Mangin, S.; Petit Watelot, S. [Institut Jean Lamour, Université de Lorraine, UMR 7198 CNRS, 54506 Vandoeuvre-lés-Nancy (France)

2017-06-15

Highlights: • MgO/CoFeB/Ta/CoFeB/MgO multilayers as synthetic ferrimagnets. • Comprehensive characterization by measurement of static and dynamic properties. • Different pinning for domain walls with different alignment of the individual layers. - Abstract: A study of the multilayer system MgO/CoFeB(1.1 nm)/Ta(t)/CoFeB(0.8 nm)/MgO is presented, where the two CoFeB layers are separated by a Ta interlayer of varying thickness t. The magnetization properties deduced from complementary techniques such as superconducting quantum interference magnetometry, ferromagnetic resonance frequency measurements and Brillouin light scattering spectroscopy can be tuned by changing the Ta thickness between t = 0.25 nm, 0.5 nm and 0.75 nm. For t = 0.5 nm, a ferromagnetic coupling is observed, whereas for t = 0.75 nm, the antiferromagnetic coupling needed to construct a synthetic ferrimagnet is realized. In the latter case, the shape of magnetic domain walls between two ferrimagnetic alignments or between a ferro- and a ferrimagnetic alignment is very different. This behavior can be interpreted as a result of the change in dipolar as well as interlayer exchange energy and domain wall pinning, which is an important conclusion for the realization of data storage devices based on synthetic ferri- and antiferromagnets.

Perpendicular magnetic anisotropy in Ta|Co40Fe40B20|MgAl2O4 structures and perpendicular CoFeB|MgAl2O4|CoFeB magnetic tunnel junction

KAUST Repository

Tao, B. S.

2014-09-08

Magnetic properties of Co40Fe40B20(CoFeB) thin films sandwiched between Ta and MgAl2O4layers have been systematically studied. For as-grown state, Ta/CoFeB/MgAl2O4structures exhibit good perpendicular magnetic anisotropy (PMA) with interface anisotropy Ki=1.22erg/cm2, which further increases to 1.30erg/cm2after annealing, while MgAl2O4/CoFeB/Ta multilayer shows in-plane magnetic anisotropy and must be annealed in order to achieve PMA. For bottom CoFeB layer, the thickness window for PMA is from 0.6 to 1.0nm, while that for top CoFeB layer is between 0.8 and 1.4nm. Perpendicular magnetic tunnel junctions (p-MTJs) with a core structure of CoFeB/MgAl2O4/CoFeB have also been fabricated and tunneling magnetoresistance ratio of about 36% at room temperature and 63% at low temperature have been obtained. The intrinsic excitations in the p-MTJs have been identified by inelastic electron-tunneling spectroscopy.

Perpendicular magnetic anisotropy in Ta|Co40Fe40B20|MgAl2O4 structures and perpendicular CoFeB|MgAl2O4|CoFeB magnetic tunnel junction

KAUST Repository

Tao, B. S.; Li, D. L.; Yuan, Z. H.; Liu, H. F.; Ali, S. S.; Feng, J. F.; Wei, H. X.; Han, X. F.; Liu, Y.; Zhao, Y. G.; Zhang, Q.; Guo, Zaibing; Zhang, Xixiang

2014-01-01

Magnetic properties of Co40Fe40B20(CoFeB) thin films sandwiched between Ta and MgAl2O4layers have been systematically studied. For as-grown state, Ta/CoFeB/MgAl2O4structures exhibit good perpendicular magnetic anisotropy (PMA) with interface anisotropy Ki=1.22erg/cm2, which further increases to 1.30erg/cm2after annealing, while MgAl2O4/CoFeB/Ta multilayer shows in-plane magnetic anisotropy and must be annealed in order to achieve PMA. For bottom CoFeB layer, the thickness window for PMA is from 0.6 to 1.0nm, while that for top CoFeB layer is between 0.8 and 1.4nm. Perpendicular magnetic tunnel junctions (p-MTJs) with a core structure of CoFeB/MgAl2O4/CoFeB have also been fabricated and tunneling magnetoresistance ratio of about 36% at room temperature and 63% at low temperature have been obtained. The intrinsic excitations in the p-MTJs have been identified by inelastic electron-tunneling spectroscopy.

Las masas de aire que afectan el sur de la provincia de Santa Fe y su relación con la precipitación diaria en enero Classification of air masses that affect the south of Santa Fe, their trajectories and the relationship between them to the the daily precipitation in January abstract

Directory of Open Access Journals (Sweden)

Alejandra S. Coronel

2010-06-01

Full Text Available El objetivo del trabajo es identificar las masas de aire que afectan el sur de Santa Fe durante los eneros de 1998-2006 y relacionarlas con la precipitación diaria, tomando como estación representativa a Zavalla (33º01´S, 60º53´O. La información diaria analizada es: temperaturas media, máxima y mínima, humedad relativa, heliofanía efectiva, presión atmosférica, precipitación y dirección de viento a las 8 y 14 horas local, campos de altura geopotencial en 1000 y 500 hPa, de temperatura en 1000 hPa y de humedad específica en 850 hPa del NCEP. Se aplica el algoritmo K-means y se identifican cuatro tipos de masas de aire: Cálida Seca (mCS: muy cálida; Cálida Húmeda (mCH: aumenta significativamente la humedad y la nubosidad respecto a mCS; Templada Seca (mTS: menores temperaturas mínimas; Templada Húmeda (mTH: muy húmeda, y bajas amplitudes térmicas diarias, asociada a condiciones previas al pasaje de frentes fríos. El 50% de días lluviosos ocurren durante mCH y el 32% con mTH, y el 93% de las más intensas acontecen durante el predominio de dichas masas. Las mTH tienen mayor eficiencia en la ocurrencia de precipitación pues en el 50% de los casos precipita, y para las mCH solo en el 27%.The aim of this work is to identify the air masses that affect the south of Santa Fe in January during 1998-2006 and to relate it to the daily precipitation, in Zavalla (33º01´S, 60º53´O. The analyzed daily information is: mean, maximum and minimum temperature, relative humidity, effective insolation, atmospheric pressure, precipitation and wind direction of the 8 and 14 hours. The fields of circulation and temperature in 1000 and 500 hPa, and specific humidity in 850 hPa, are calculated using NCEP Reanálisis data. Analysis of cluster k-means is applied and it determines four types of air masses: Warm Drought: a very warm air mass; Warm Humid: it increases the humidity and cloudiness, Moderate Dry: air mass with the smallest minimum

75 FR 64719 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2010-10-20

..., Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or E- mail: [email protected] Continue Presentation on LANL's Environmental Surveillance Report. 5 p.m. Dinner Break. 6 p.m. Public...: Minutes will be available by writing or calling Menice Santistevan at the address or phone number listed...

Santa Rosa de Lima: uma santa anoréxica na América Latina? Santa Rosa de Lima: ¿una santa anoréxica en Latinoamérica? Saint Rose of Lima: an anorexic saint in Latin America?

Directory of Open Access Journals (Sweden)

Cybelle Weinberg

2005-04-01

Full Text Available A literatura especializada tem nos mostrado que é grande a semelhança entre o comportamento alimentar das santas jejuadoras medievais e o das anoréxicas atuais. No entanto, há poucas referências sobre a existência de santas jejuadoras na América Latina. No presente trabalho, os autores salientam aspectos da vida de Santa Rosa de Lima, Patrona da América e Filipinas, que poderiam ser descritos como comportamentos anoréxicos. Comparando os aspectos psicopatológicos da vida de Santa Rosa com o comportamento das anoréxicas atuais, pareceu confirmar-se um padrão uniforme de comportamento, especialmente quanto ao aspecto imitativo, fator que poderia levar as jovens da atualidade a desenvolverem um transtorno alimentar após terem algum tipo de informação sobre o transtorno.La literatura especializada nos muestra gran similitud entre el comportamiento alimentar de las santas de la edad media que ayunaban y el de las anoréxicas de la actualidad. Hay pocas informaciones sobre santas que practicaban ayuno en Latinoamérica. En este artículo, los autores resaltan aspectos de la vida de santa Rosa de Lima, Patrona de América y Filipinas, que pueden ser considerados como comportamientos anoréxicos. Al comparar aspectos psicopatológicos de la vida de santa Rosa con el comportamiento de anoréxicas de la actualidad, parece que se confirma un modelo uniforme de comportamiento, especialmente respecto al aspecto de imitación, hecho que podría llevar a las jóvenes de hoy a desarrollar un trastorno de la alimentación luego de recibir informaciones sobre el tema.The specialized literature has shown us the great similarity between the eating habits of medieval fasting women saints and today's anorexic women. Nonetheless, there are few references to the existence of such fasting women saints in Latin America. The authors of this paper present some aspects of the life of Saint Rose of Lima, the patroness of the Americas and the Philippines, that

Magnetic and structural characterizations on nanoparticles of FePt, FeRh and their composites

International Nuclear Information System (INIS)

Ko, Hnin Yu Yu; Suzuki, Takao; Nam, Nguyen T.; Phuoc, Nguyen N.; Cao Jiangwei; Hirotsu, Yoshihiko

2008-01-01

The various compositions of FePt and FeRh nanoparticles, and their composite particles have been fabricated by the solution-phase chemical method and their magnetic properties characterized. High-resolution transmission electron microscopic observations indicate that mono-dispersed FeRh and FePt/FeRh nanoparticles are fabricated with the average size of 3-5 nm. However, larger size particles are distributed in the annealed state. From X-ray diffraction results, the as-deposited FeRh nanoparticles reveal a chemically disordered fcc structure which can be transformed into CsCl-type structure through thermal annealing. Similarly, the annealed FePt nanoparticles show the L1 0 -phase fct structure although the fcc structure is apparent in the as-deposited state. It is also found that the first time in the exchange bias effect in the composite of ferromagnetic (FePt) and anti-ferromagnetic (FeRh) nanoparticles; result in a shift of the hysteresis loop after field cooling process

Thermal decomposition of barium ferrate(VI): Mechanism and formation of FeIV intermediate and nanocrystalline Fe2O3 and ferrite

International Nuclear Information System (INIS)

Machala, Libor; Sharma, Virender K.; Kuzmann, Ernö; Homonnay, Zoltán; Filip, Jan; Kralchevska, Radina P.

2016-01-01

Simple high-valent iron-oxo species, ferrate(VI) (Fe VI O 4 2− , Fe(VI)) has applications in energy storage, organic synthesis, and water purification. Of the various salts of Fe(VI), barium ferrate(VI) (BaFeO 4 ) has also a great potential as a battery material. This paper presents the thermal decomposition of BaFeO 4 in static air and nitrogen atmosphere, monitored by combination of thermal analysis, Mössbauer spectroscopy, X-ray powder diffraction, and electron-microscopic techniques. The formation of Fe IV species in the form of BaFeO 3 was found to be the primary decomposition product of BaFeO 4 at temperature around 190 °C under both studied atmospheres. BaFeO 3 was unstable in air reacting with CO 2 to form barium carbonate and speromagnetic amorphous iron(III) oxide nanoparticles (<5 nm). Above 600 °C, a solid state reaction between BaCO 3 and Fe 2 O 3 occurred, leading to the formation of barium ferrite nanoparticles, BaFe 2 O 4 (20–100 nm). - Highlights: • We explained the mechanism of thermal decomposition of barium ferrate(VI). • We confirmed the formation of Fe(IV) intermediate phase during the decomposition. • The mechanism of the decomposition is influenced by a presence of carbon dioxide.

Formation of FePt nanodots by wetting of nanohole substrates

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Ahmed M. Abdelgawad

2016-05-01

Full Text Available Large area arrays of FePt nanodots are fabricated on patterned substrates made of SiOx, SiNx and TiNx. The templates have a depth of ∼10 nm and a pitch of ∼20 nm with 18 nm wide holes. FePt is sputtered on the nanohole arrays, then back-etched, leaving a highly ordered array of FePt nanodots behind. To promote phase transformation to the L10 phase, the samples are annealed at temperatures of 550-650° C. During annealing, the FePt strongly dewets SiOx and SiNx substrates, causing sintering and coalescence of the FePt nanodots, but the nanodots remain highly ordered on the TiNx substrate. The nanodot arrays on TiNx are characterized magnetically before and after annealing. The out-of-plane coercivity increases by ∼1 kOe, suggesting partial transformation to the L10 phase. We also show that a capping layer can be sputtered on top of the nanodot arrays prior to annealing to prevent dewetting.

You're a "What"? Santa Claus

Science.gov (United States)

Royster, Sara

2013-01-01

Professional Santas entertain children and adults during the holiday season at all types of events. They work at shopping malls or stores; entertain crowds at parades and tree lightings; and make appearances at holiday parties, charity events, and people's homes. Most Santas work during the Christmas holiday season, which usually lasts from late…

Seasonal changes in Fe along a glaciated Greenlandic fjord.

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Mark James Hopwood

2016-03-01

Full Text Available Greenland’s ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from 6 glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (<10 m, outflowing, low-salinity surface layer. Dissolved (<0.2 µm Fe concentrations in meltwater entering Godthåbsfjord (200 nM, in freshly melted glacial ice (mean 38 nM and in surface waters close to a land terminating glacial system (80 nM all indicated high Fe inputs into the fjord in summer. Total dissolvable (unfiltered at pH <2.0 Fe was similarly high with concentrations always in excess of 100 nM throughout the fjord and reaching up to 5.0 µM close to glacial outflows in summer. Yet, despite the large seasonal freshwater influx into the fjord, Fe concentrations near the fjord mouth in the out-flowing surface layer were similar in summer to those measured before the meltwater season. Furthermore, turbidity profiles indicated that sub-glacial particulate Fe inputs may not actually mix into the outflowing surface layer of this fjord. Emphasis has previously been placed on the possibility of increased Fe export from Greenland as meltwater fluxes increase. Here we suggest that in-fjord processes may be effective at removing Fe from surface waters before it can be exported to coastal seas.

Simple electrodepositing of CoFe/Cu multilayers: Effect of ferromagnetic layer thicknesses

Energy Technology Data Exchange (ETDEWEB)

Tekgül, Atakan, E-mail: atakantekgul@gmail.com [Akdeniz University, Physics Department, Science Faculty, TR-07058 Antalya (Turkey); Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Alper, Mürsel [Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Kockar, Hakan [Balikesir University, Physics Department, Science and Literature Faculty, TR-10145 Balikesir (Turkey)

2017-01-01

The CoFe/Cu magnetic multilayers were produced by changing CoFe ferromagnetic layers from 3 nm to 10 nm using electrodeposition. By now, the thinnest Cu (0.5 nm) layer thicknesses were used to see whether the GMR effect in the multilayers can be obtained or not since the pinning of non-magnetic layer between the ferromagnetic layers is required. For the proper depositions, the cyclic voltammograms was used, and the current–time transients were obtained. The Cu and CoFe layers were deposited at a cathode potential of −0.3 and −1.5 V with respect to saturated calomel electrode, respectively. From the XRD patterns, the multilayers were shown to be fcc crystal structures. For the magnetization measurements, saturation magnetization increases from 160 to 600 kA/m from 3 to 8 nm ferromagnetic layer thicknesses. And, the coercivity values increase until the 8 nm of the CoFe layer thickness. It is seen that the thin Cu layer (fixed at 0.5 nm) and pinholes support the random magnetization orientation and thus all multilayers exhibited the giant magnetoresistance (GMR) effect, and the highest GMR value was observed about 5.5%. And, the variation of GMR field sensitivity was calculated. The results show that the GMR and GMR sensitivity are compatible among the multilayers. The CoFe/Cu magnetic multilayers having GMR properties are used in GMR sensors and hard disk drive of the nano-technological devices. - Highlights: • The much thinner (0.5 nm) Cu layer was used to obtain the GMR effect on the electrodeposited CoFe/Cu multilayers. • All samples exhibited GMR and the maximum GMR value was 5.5%. • The M{sub s} and the H{sub c} changed with increasing magnetic layer thickness.

Mössbauer Studies of Core-Shell FeO/Fe3O4 Nanoparticles

Science.gov (United States)

Kamzin, A. S.; Valiullin, A. A.; Khurshid, H.; Nemati, Z.; Srikanth, H.; Phan, M. H.

2018-02-01

FeO/Fe3O4 nanoparticles were synthesized by thermal decomposition. Electron microscopy revealed that these nanoparticles were of the core-shell type and had a spherical shape with an average size of 20 nm. It was found that the obtained FeO/Fe3O4 nanoparticles had exchange coupling. The effect of anisotropy on the efficiency of heating (hyperthermic effect) of FeO/Fe3O4 nanoparticles by an external alternating magnetic field was examined. The specific absorption rate (SAR) of the studied nanoparticles was 135 W/g in the experiment with an external alternating magnetic field with a strength of 600 Oe and a frequency of 310 kHz. These data led to an important insight: the saturation magnetization is not the only factor governing the SAR, and the efficiency of heating of magnetic FeO/Fe3O4 nanoparticles may be increased by enhancing the effective anisotropy. Mössbauer spectroscopy of the phase composition of the synthesized nanoparticles clearly revealed the simultaneous presence of three phases: magnetite Fe3O4, maghemite γ-Fe2O3, and wustite FeO.

Sandra Patricia Rodríguez Ávila. Sujeción, corrección y disciplina: pedagogía social de masas en Santa Fe de Bogotá 1780-1821

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Juan Carlos Villamizar

2008-01-01

Full Text Available El libro ganador del vii Premio Nacional de Educación Francisca Radke, versión 2005-2006, se compone de una introducción y tres capítulos, en los que la autora se ocupa de las prácticas de sujeción, corrección y disciplina a finales del siglo xviii y comienzos del xix, en que la administración colonial llegó a su fin en América. Los dos primeros capítulos abordan la problemática de la pobreza y las propuestas de cómo tratarla. El tercer capítulo se ocupa de la pedagogía social de masas y de la asistencia, enseñanza y corrección de pobres, mendigos, vagos y malentretenidos en Santa Fe de Bogotá entre 1780 y 1820. A diferencia de los dos primeros capítulos, este último está construido estrictamente con fuentes primarias.

Constraining Line-of-sight Confusion in the Corona Using Linearly Polarized Observations of the Infrared FeXIII 1075nm and SiX 1430nm Emission Lines

Science.gov (United States)

Dima, G. I.; Kuhn, J. R.; Berdyugina, S.

2017-12-01

Measurements of the coronal magnetic field are difficult because of the intrinsically faint emission of coronal plasma and the large spurious background due to the bright solar disk. This work addresses the problem of resolving the confusion of the line-of-sight (LOS) integration through the optically-thin corona being observed. Work on developing new measuring techniques based on single-point inversions using the Hanle effect has already been described (Dima et al. 2016). It is important to develop a technique to assess when the LOS confusion makes comparing models and observations problematic. Using forward integration of synthetic emission through magnetohydrodynamic (MHD) models together with simultaneous linearly polarized observations of the FeXIII 1075nm and SiX 1430nm emission lines allows us to assess LOS confusion. Since the lines are both in the Hanle saturated regime their polarization angles are expected to be aligned as long as the gas is sampling the same magnetic field. If significant contributions to the emission is taking place from different regions along the LOS due to the additive nature of the polarized brightness the measured linear polarization between the two lines will be offset. The size of the resolution element is important for this determination since observing larger coronal regions will confuse the variation along the LOS with that in the plane-of-sky. We also present comparisons between synthetic linearly polarized emission through a global MHD model and observations of the same regions obtained using the 0.5m Scatter-free Observatory for Limb Active Regions and Coronae (SOLARC) telescope located on Haleakala, Maui. This work is being done in preparation for the type of observations that will become possible when the next generation 4m DKIST telescope comes online in 2020.

Columnar grain growth of FePt(L10) thin films

International Nuclear Information System (INIS)

Yang En; Ho Hoan; Laughlin, David E.; Zhu Jiangang

2012-01-01

An experimental approach for obtaining perpendicular FePt-SiOx thin films with a large height to diameter ratio FePt(L1 0 ) columnar grains is presented in this work. The microstructure for FePt-SiOx composite thin films as a function of oxide volume fraction, substrate temperature, and film thickness is studied by plan view and cross section TEM. The relations between processing, microstructure, epitaxial texture, and magnetic properties are discussed. By tuning the thickness of the magnetic layer and the volume fraction of oxide in the film at a sputtering temperature of 410 deg. C, a 16 nm thick perpendicular FePt film with ∼8 nm diameter of FePt grains was obtained. The height to diameter ratio of the FePt grains was as large as 2. Ordering at lower temperature can be achieved by introducing a Ag sacrificial layer.

Microstructure and Magnetic Properties of NdFeB Films through Nd Surface Diffusion Process

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Wenfeng Liu

2017-01-01

Full Text Available Ta/Nd/NdFeB/Nd/Ta films were deposited by magnetron sputtering on Si (100 substrates and subsequently annealed for 30 min at 923 K in vacuum. It was found that the microstructure and magnetic properties of Ta/Nd/NdFeB/Nd/Ta films strongly depend on the NdFeB layer thickness. With NdFeB layer thickness increasing, both the grain size and the strain firstly reduce and then increase. When NdFeB layer thickness is 750 nm, the strain reaches the minimum value. Meanwhile, both the in-plane and perpendicular coercivities firstly drastically increase and then slowly decrease with NdFeB layer thickness increasing. The highest in-plane and perpendicular coercivities can be obtained at NdFeB layer thickness of 750 nm, which are 21.2 kOe and 19.5 kOe, respectively. In addition, the high remanence ratio (remanent magnetization/saturation magnetization of 0.87 can also be achieved in Ta/Nd/NdFeB (750 nm/Nd/Ta film.

ZnFe2O4 Containing Nanoparticles: Synthesis and Magnetic Properties

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Zālīte Ilmārs

2017-05-01

Full Text Available Solid solutions of Co1−xZnxFe2O4 and Ni1−xZnxFe2O4 (0 < x < 1 nanoparticles were synthesized by sol-gel self-propagating combustion method. The obtained single cubic phase product has a specific surface area 25 m2∙g−1 to 33 m2∙g−1 and crystallite size 25 nm to 40 nm. Lattice parameters change linearly from 8.371 A (CoFe2O4 and 8.337 A (NiFe2O4 to 8.431 A (ZnFe2O4. The saturation magnetization (Ms changes non-linearly from 60.8 emu∙g−1 (CoFe2O4, respectively, from 35.6 emu∙g−1 (NiFe2O4 to 3.3 emu∙g−1 (ZnFe2O4 reaching maximal value 76.1 emu∙g−1 for Co0.8Zn0.2Fe2O4 and 64.9 emu∙g−1 – for Ni0.6Zn0.4Fe2O4.

Growth and magnetic study of sputtered Fe/Al multilayers

International Nuclear Information System (INIS)

Cherif, S.M.; Bouziane, K.; Roussigne, Y.; Al-Busaidy, M.

2007-01-01

Brillouin light scattering (BLS) and vibrating sample magnetometry (VSM) were used to study the effect of interfacial intermixing and microstructure on the magnetic properties of DC magnetron sputtered Fe/Al multilayers (MLs) on Si(1 0 0) substrate. Three samples with nominal composition [Al (4 nm)/Fe (3.7 nm)] x18 and deposited under different negative DC bias voltages (V b = -50, -200 and -400 V) have been investigated. The X-ray diffraction results indicate that the FeAl MLs have a poor crystallinity with no evidence of the absence of B2 phase. The grazing X-ray reflectivity results suggest that the interfacial roughness and intermixing were gradually reduced from 0.7 to 0.5 nm (±0.05 nm) by increasing V b from -50 to -400 V. The magnetization measurements demonstrate the presence of in-plane uniaxial anisotropy and magnetically dead interfacial layers. The BLS results reveal spin-wave surface modes whose frequencies also depend on the applied V b . The same trend upon V b was observed for the perpendicular and in-plane anisotropies

Growth and magnetic study of sputtered Fe/Al multilayers

Energy Technology Data Exchange (ETDEWEB)

Cherif, S.M. [LPMTM (CNRS-UPR 9001), Universite Paris 13, 99 Av. J.B. Clement, 93430 Villetaneuse (France); Bouziane, K. [LPMTM (CNRS-UPR 9001), Universite Paris 13, 99 Av. J.B. Clement, 93430 Villetaneuse (France) and Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman)]. E-mail: bouzi@squ.edu.om; Roussigne, Y. [LPMTM (CNRS-UPR 9001), Universite Paris 13, 99 Av. J.B. Clement, 93430 Villetaneuse (France); Al-Busaidy, M. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman)

2007-03-15

Brillouin light scattering (BLS) and vibrating sample magnetometry (VSM) were used to study the effect of interfacial intermixing and microstructure on the magnetic properties of DC magnetron sputtered Fe/Al multilayers (MLs) on Si(1 0 0) substrate. Three samples with nominal composition [Al (4 nm)/Fe (3.7 nm)]{sub x18} and deposited under different negative DC bias voltages (V {sub b} = -50, -200 and -400 V) have been investigated. The X-ray diffraction results indicate that the FeAl MLs have a poor crystallinity with no evidence of the absence of B2 phase. The grazing X-ray reflectivity results suggest that the interfacial roughness and intermixing were gradually reduced from 0.7 to 0.5 nm ({+-}0.05 nm) by increasing V {sub b} from -50 to -400 V. The magnetization measurements demonstrate the presence of in-plane uniaxial anisotropy and magnetically dead interfacial layers. The BLS results reveal spin-wave surface modes whose frequencies also depend on the applied V{sub b}. The same trend upon V {sub b} was observed for the perpendicular and in-plane anisotropies.

77 FR 12044 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2012-02-28

..., Santa Fe, NM 87506. Phone (505) 995-0393; Fax (505) 989-1752 or Email: [email protected]/Bernalillo County Water Authority 5 p.m.--Dinner Break 6 p.m.--Public Comment Period 6:15 p.m.--Consideration...: Minutes will be available by writing or calling Menice Santistevan at the address or phone number listed...

75 FR 35446 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2010-06-22

..., Santa Fe, NM 87505. Phone (505) 995-0393; fax (505) 989-1752 or e- mail: [email protected] Dinner Break. 6 p.m. Public Comment Period. 6:15 p.m. Continue Consideration and Action on Draft... Santistevan at the address or phone number listed above. Minutes and other Board documents are on the Internet...

75 FR 9886 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2010-03-04

..., Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or E- mail: [email protected] Area G, George Henckel 4 p.m. Consideration and Action on Draft Recommendation(s) 5 p.m. Dinner Break 6...: Minutes will be available by writing or calling Menice Santistevan at the address or phone number listed...

76 FR 78909 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2011-12-20

..., Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or Email: [email protected] Recommendation(s) to DOE, Ralph Phelps. 5 p.m. Dinner Break. 6 p.m. Public Comment Period . 6:15 p.m... calling Menice Santistevan at the address or phone number listed above. Minutes and other Board documents...

Ferromagnetic resonance on oxideless magnetic Fe and FeRh nanoparticles; Ferromagnetische Resonanz an oxidfreien magnetischen Fe und FeRh Nanopartikeln

Energy Technology Data Exchange (ETDEWEB)

Trunova, Anastasia

2009-05-25

This work is dedicated to investigations of structural and magnetic properties of the colloidal Fe/Fe{sub x}O{sub y} nanocubes (13 nm) and the Fe{sub x}Rh{sub 100-x} core/shell nanoparticles (2 nm). As compared with other works, where the measurements on oxidized nanoparticles were carried out, we additionally performed investigations on nanoparticles in an oxide free state. In order to make the measurements on oxide free particles possible, oxygen- and hydrogenplasma was used to remove the ligands and reduce the oxide shell of the Fe nanocubes. The oxide free Fe nanocubes were covered with a Ag/Pt protective coating to prevent them from new oxidation. This method allowed carrying out the magnetic measurements on oxide free Fe nanocubes. Micromagnetic simulations as well as simulations of the high frequency susceptibility were used for the data analysing. It was found that both the g-factor g=2.09{+-}0.01 and the anisotropy constant K{sub 4}=(4.8{+-}0.5).10{sup 4} J/m{sup 3} coincide with that of bulk iron. However, the saturation magnetization M{sub S}(5 K)=(1.2{+-}0.12).10{sup 6} A/m differs from the bulk value by 30%. The reduction by 30% compared to the bulk value in the case of nanoparticles may be caused by the following possible reasons: a) the presence of inner oxide layer (approx. 10 at.%) that cannot be reduced; b) the anti-parallel order between magnetic moments of iron core and magnetic moments of antiferomagnetic iron oxide; c) some structural changes of the surface after plasma treatment. The obtained damping parameter {alpha}=0.03{+-}0.005 is ten times larger than that of the Fe layers as it is known for nanoparticles systems in general. The core/shell Fe{sub x}Rh{sub 100-x} nanoparticles (x=80,50) were produced under Ar-atmosphere and were sealed into a quartz tube to prevent oxidation. The analysis of g-factors shows that the value for the FePh nanoparticles with Fe-rich core is larger (g=2.08{+-}0.01) than that for the nanoparticles with Rh

Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

International Nuclear Information System (INIS)

Miko, Annamaria; Kuzmann, Erno; Lakatos-Varsanyi, Magda; Kakay, Attila; Nagy, Ferenc; Varga, Lajos Karoly

2005-01-01

57 Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and 57 Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t on = 2 ms), with short relaxation time (t off = 9 ms) and low current density (I p = 0.05 Acm -2 ) or at short deposition time (t on = 1 ms) with long relaxation time (t off = 250 ms) and high current density (I p = 1.0 Acm -2 ). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

High magnetic coercivity of FePt-Ag/MgO granular nanolayers

Science.gov (United States)

Roghani, R.; Sebt, S. A.; Khajehnezhad, A.

2018-06-01

L10-FePt ferromagnetic nanoparticles have a hight coercivity of Tesla order. Thus, these nanoparticles, with size of 10 to 15 nm and uniform surface distribution, are suitable in magnetic data storage technology with density of more than 1GB. In order to improve structural and magnetic properties of FePt nanoparticles, some elements and combinations have been added to compound. In this research, we show that due to the presence of the Ag, the phase transition temperature of FePt from fcc to L10-fct phase decreases. The presence of Ag as an additive in FePt-Ag nanocomposite, increases the magnetic coercivity. This nanocomposite, with 10% Ag, was deposited by magnetron sputtering on the MgO heat layer. VSM results of 10 nm nanoparticles show that coercivity has increased up to 1.4 T. XRD and FESEM results confirm that the size of the L10-FePt nanoparticles are 10 nm and their surface distribution are uniform. Ag gradually form nano scale clusters with separate lattice and FePt-Ag nanocomposite appears. The result of this process is emptiness of Ag position in FePt-fcc lattice. So, the mobility of Fe and Pt atoms in this lattice increases and it can be possible for them to move in lower temperature. This mechanism explain the effect of Ag on decreasing the transition temperature to fct-L10 phase, and hight coercivity of FePt nanoparticles.

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

International Nuclear Information System (INIS)

Julian Fernandez, C. de; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P.

2004-01-01

The nanostructural and magnetic properties of Fe-Al/SiO 2 granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the α-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of α-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior

Structural and magnetic properties of Fe-Al silica composites prepared by sequential ion implantation

Energy Technology Data Exchange (ETDEWEB)

Julian Fernandez, C. de E-mail: dejulian@padova.infm.it; Tagliente, M.A.; Mattei, G.; Sada, C.; Bello, V.; Maurizio, C.; Battaglin, G.; Sangregorio, C.; Gatteschi, D.; Tapfer, L.; Mazzoldi, P

2004-02-01

The nanostructural and magnetic properties of Fe-Al/SiO{sub 2} granular solids prepared by ion implantation have been investigated. A strong effect of the implantation order of the Fe and Al ions has been evidenced. By implanting first the Al ions and later Fe ions, 5-40 nm core-shell nanoparticles are formed with a magnetic behavior similar to that of Fe. The lattice parameter of the nanoparticles is consistent with that of the {alpha}-Fe. By changing the implantation order, 10-15 nm core-shell nanoparticles of a bcc Fe-based phase with a lattice 2.5% smaller than that of {alpha}-Fe are formed. The temperature dependence of the magnetization indicates a superparamagnetic behavior.

Electrical control of antiferromagnetic metal up to 15 nm

Science.gov (United States)

Zhang, PengXiang; Yin, GuFan; Wang, YuYan; Cui, Bin; Pan, Feng; Song, Cheng

2016-08-01

Manipulation of antiferromagnetic (AFM) spins by electrical means is on great demand to develop the AFM spintronics with low power consumption. Here we report a reversible electrical control of antiferromagnetic moments of FeMn up to 15 nm, using an ionic liquid to exert a substantial electric-field effect. The manipulation is demonstrated by the modulation of exchange spring in [Co/Pt]/FeMn system, where AFM moments in FeMn pin the magnetization rotation of Co/Pt. By carrier injection or extraction, the magnetic anisotropy of the top layer in FeMn is modulated to influence the whole exchange spring and then passes its influence to the [Co/Pt]/FeMn interface, through a distance up to the length of exchange spring that fully screens electric field. Comparing FeMn to IrMn, despite the opposite dependence of exchange bias on gate voltages, the same correlation between carrier density and exchange spring stiffness is demonstrated. Besides the fundamental significance of modulating the spin structures in metallic AFM via all-electrical fashion, the present finding would advance the development of low-power-consumption AFM spintronics.

Synthesis of novel magnetic iron metal-silica (Fe-SBA-15) and magnetite-silica (Fe{sub 3}O{sub 4}-SBA-15) nanocomposites with a high iron content using temperature-programed reduction

Energy Technology Data Exchange (ETDEWEB)

Yiu, H H P [Department of Chemistry, University of Liverpool, Liverpool, Merseyside L69 7ZD (United Kingdom); Keane, M A [Chemical Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Lethbridge, Z A D [Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Lees, M R [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom); Haj, A J El; Dobson, J [Institute of Science and Technology in Medicine, Keele University, Thornburrow Drive, Hartshill, Stoke-on-Trent ST4 7QB (United Kingdom)], E-mail: j.p.dobson@keele.ac.uk

2008-06-25

Magnetic iron metal-silica and magnetite-silica nanocomposites have been prepared via temperature-programed reduction (TPR) of an iron oxide-SBA-15 (SBA: Santa Barbara Amorphous) composite. TPR of the starting SBA-15 supported Fe{sub 2}O{sub 3} generated Fe{sub 3}O{sub 4} and FeO as stepwise intermediates in the ultimate formation of Fe-SBA-15. The composite materials have been characterized by means of x-ray diffraction, high resolution transmission electron microscopy and SQUID (superconducting quantum interference device) magnetometry. The Fe oxide and metal components form a core, as nanoscale particles, that is entrapped in the SBA-15 pore network. Fe{sub 3}O{sub 4}-SBA-15 and Fe-SBA-15 exhibited superparamagnetic properties with a total magnetization value of 17 emu g{sup -1}. The magnetite-silica composite (at an Fe{sub 3}O{sub 4} loading of 30% w/w) delivered a magnetization that exceeded values reported in the literature or obtained with commercial samples. Due to the high pore volume of the mesoporous template, the magnetite content can be increased to 83% w/w with a further enhancement of magnetization.

Synthesis and electrochemical properties of nanosized LiFeO2 particles with a layered rocksalt structure for lithium batteries

International Nuclear Information System (INIS)

Hirayama, Masaaki; Tomita, Hiroki; Kubota, Kei; Ido, Hidekazu; Kanno, Ryoji

2012-01-01

Highlights: ► 40-nm-sized O3-LiFeO 2 exhibits higher discharge capacities and rate characteristics than 400-nm-sized O3-LiFeO 2 . ► The cation disorder of Li and Fe ions might have affected the electrochemical activity of the O3-LiFeO 2 nanoparticles. ► A phase change from a layered structure to a cubic structure during electrochemical cycling. ► The new cubic phase allowed a stable electrochemical reaction between 4.5 and 1.0 V. -- Abstract: Layered rocksalt-type LiFeO 2 particles (O3-LiFeO 2 ) with average particle sizes of ca. 40 and 400 nm were synthesized by an ion exchange reaction from α-NaFeO 2 precursors. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images confirmed the formation of nanosized O3-LiFeO 2 . 40-nm LiFeO 2 exhibited a higher discharge capacity (115 mAh g −1 ) than 400-nm LiFeO 2 (80 mAh g −1 ), and also had better rate characteristics. The downsizing effect and cation disorder between the lithium and iron layers may have improved the electrochemical activity of the LiFeO 2 particles. Transmission electron microscopy (TEM) observation indicated a phase transition from O3-LiFeO 2 to a cubic lattice system during the electrochemical process. The cubic lithium iron oxide exhibited stable electrochemical reactions based on the Fe 2+ /Fe 3+ and Fe 2+ /Fe 0 redox couples at voltages between 4.5 and 1.0 V. The discharge capacities of 40-nm LiFeO 2 were ca. 115, 210, and 390 mAh g −1 under cutoff voltages of 4.5–2.0 V, 4.5–1.5 V, and 4.5–1.0 V, respectively.

Rainfall, soil moisture, and runoff dynamics in New Mexico pinon-juniper woodland watersheds

Science.gov (United States)

Carlos Ochoa; Alexander Fernald; Vincent Tidwell

2008-01-01

Clearing trees in pinon-juniper woodlands may increase grass cover and infiltration, leading to reduced surface runoff and erosion. This study was conducted to evaluate pinon-juniper hydrology conditions during baseline data collection in a paired watershed study. We instrumented six 1.0 to 1.3 ha experimental watersheds near Santa Fe, NM to collect rainfall, soil...

77 FR 66599 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2012-11-06

..., Santa Fe, NM 87506. Phone (505) 995-0393; Fax (505) 989-1752 or Email: [email protected] Mayer 3:00 p.m. Break 3:15 p.m. Update on Framework Agreement 5:00 p.m. Dinner Break 6:00 p.m. Public... will be available by writing or calling Menice Santistevan at the address or phone number listed above...

75 FR 53280 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2010-08-31

..., Suite B, Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or E- mail: [email protected]), Andrew Green 4:15 p.m. Storm Water Management at LANL 5 p.m. Dinner Break 6 p.m. Public Comment Period 6... calling Menice Santistevan at the address or phone number listed above. Minutes and other Board documents...

76 FR 11773 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2011-03-03

..., Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or E- mail: [email protected] Budget. 4:15 p.m. Presentation on the Testing and Handling of a Water Sample. 5 p.m. Dinner Break. 6 p.m... will be available by writing or calling Menice Santistevan at the address or phone number listed above...

76 FR 51361 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Science.gov (United States)

2011-08-18

..., Suite B, Santa Fe, NM 87505. Phone (505) 995-0393; Fax (505) 989-1752 or e- mail: [email protected] Stewardship, Tom Longo. 4:30 p.m. Discussion of Draft Recommendation(s) to DOE. 5 p.m. Dinner... Santistevan at the address or phone number listed above. Minutes and other Board documents are on the Internet...

Exchange coupling behavior in bimagnetic CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Leite, G.C.P. [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Chagas, E.F., E-mail: efchagas@fisica.ufmt.br [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Pereira, R.; Prado, R.J. [Instituto de Fisica, Universidade Federal de Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Terezo, A.J. [Departamento de Quimica, Universidade Federal do Mato Grosso, 78060-900 Cuiaba-MT (Brazil); Alzamora, M.; Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud 150 Urca, Rio de Janeiro (Brazil)

2012-09-15

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe{sub 2}O{sub 4} and ferrimagnetic oxide/ferromagnetic metal CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite. The latter compound is a good system to study hard ferrimagnet/soft ferromagnet exchange coupled. Two steps were followed to synthesize the bimagnetic CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite: (i) first, preparation of CoFe{sub 2}O{sub 4} nanoparticles using a simple hydrothermal method, and (ii) second, reduction reaction of cobalt ferrite nanoparticles using activated charcoal in inert atmosphere and high temperature. The phase structures, particle sizes, morphology, and magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles were investigated by X-Ray diffraction (XRD), Mossbauer spectroscopy (MS), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) with applied field up to 3.0 kOe at room temperature and 50 K. The mean diameter of CoFe{sub 2}O{sub 4} particles is about 16 nm. Mossbauer spectra revealed two sites for Fe{sup 3+}. One site is related to Fe in an octahedral coordination and the other one to the Fe{sup 3+} in a tetrahedral coordination, as expected for a spinel crystal structure of CoFe{sub 2}O{sub 4}. TEM measurements of nanocomposite showed the formation of a thin shell of CoFe{sub 2} on the cobalt ferrite and indicate that the nanoparticles increase to about 100 nm. The magnetization of the nanocomposite showed a hysteresis loop that is characteristic of exchange coupled systems. A maximum energy product (BH){sub max} of 1.22 MGOe was achieved at room temperature for CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposites, which is about 115% higher than the value obtained for CoFe{sub 2}O{sub 4} precursor. The exchange coupling interaction and the enhancement of product (BH){sub max} in nanocomposite CoFe{sub 2}O{sub 4}/CoFe{sub 2} are discussed. - Highlights: Black-Right-Pointing-Pointer CoFe{sub 2}O{sub 4}/CoFe{sub 2} nanocomposite

Magnetic properties of {alpha}-Fe and Fe{sub 3}C nanowires

Energy Technology Data Exchange (ETDEWEB)

Lutz, M U; Weissker, U; Wolny, F; Mueller, C; Loeffler, M; Muehl, T; Leonhardt, A; Buechner, B; Klingeler, R, E-mail: m.lutz@ifw-dresden.d [Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany)

2010-01-01

The magnetic properties of single domain {alpha}-Fe and Fe{sub 3}C nanowires encapsulated within Multi Walled Carbon Nanotubes (MWNT) are investigated with a Magnetic Force Microscope (MFM). The wires are formed during the Chemical Vapour Deposition growth process, partially filling the hollow center of the MWNTs. The wires have a diameter variation of 10-60nm and can be several {mu}m long. The phase and crystal orientation of the filling relative to the long tube axis are probed by Transmission Electron Microscopy. The remanent magnetization states of the wires are investigated by MFM imaging. The {alpha}-Fe wires show shape dominated magnetization along the tube axis, whereas the FesC wires show a perpendicular magnetization imposed by magneto-crystalline anisotropy. Switching fields of {alpha}-Fe nanowires are determined by the application of an in-situ magnetic field, revealing a tip triggered magnetization reversal by localized nucleation.

Arsenic content of soils from three regions of Santa Catarina State

Directory of Open Access Journals (Sweden)

Leticia Cristina de Souza

2016-03-01

Full Text Available The determination of trace elements is necessary in order to monitor their entry into the soil system and to remediate contaminated areas. The purpose of this study was to determine the natural content of arsenic (As in soils of three regions of Santa Catarina State (SC: the Southern Plateau, the Metropolitan area and the Southern Coast. Arsenic content was obtained after digestion in a microwave oven, following the USEPA 3051 A protocol and quantification was made by atomic absorption spectrometry with electrothermal atomization. The results were analyzed by the Scott-Knott test at a 5% significance level. Soil attributes that best correlated with arsenic content were clay, organic carbon, cation exchange capacity and Al and Fe oxides. The arsenic levels are related to the source material and the slope of regional soils.

Effect of Ta buffer and NiFe seed layers on pulsed-DC magnetron sputtered Ir{sub 20}Mn{sub 80}/Co{sub 90}Fe{sub 10} exchange bias

Energy Technology Data Exchange (ETDEWEB)

Oksuezoglu, Ramis Mustafa, E-mail: rmoksuzoglu@anadolu.edu.t [University of Anadolu, Faculty of Engineering and Architecture, Department of Materials Sciences and Engineering, Iki Eyluel Campus, 26555 Eskisehir (Turkey); Yildirim, Mustafa; Cinar, Hakan [University of Anadolu, Faculty of Engineering and Architecture, Department of Materials Sciences and Engineering, Iki Eyluel Campus, 26555 Eskisehir (Turkey); Hildebrandt, Erwin; Alff, Lambert [Department of Materials Sciences, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany)

2011-07-15

A systematic investigation has been done on the correlation between texture, grain size evolution and magnetic properties in Ta/Ni{sub 81}Fe{sub 19}/Ir{sub 20}Mn{sub 80}/Co{sub 90}Fe{sub 10}/Ta exchange bias in dependence of Ta buffer and NiFe seed layer thickness in the range of 2-10 nm, deposited by pulsed DC magnetron sputtering technique. A strong dependence of <1 1 1> texture on the Ta/NiFe thicknesses was found, where the reducing and increasing texture was correlated with exchange bias field and unidirectional anisotropy energy constant at both NiFe/IrMn and IrMn/CoFe interfaces. However, a direct correlation between average grain size in IrMn and H{sub ex} and H{sub c} was not observed. L1{sub 2} phase IrMn{sub 3} could be formed by thickness optimization of Ta/NiFe layers by deposition at room temperature, for which the maximum exchange coupling parameters were achieved. We conclude finally that the coercivity is mainly influenced by texture induced interfacial effects at NiFe/IrMn/CoFe interfaces developing with Ta/NiFe thicknesses. - Research highlights: We discussed the influence of Ta/NiFe thicknesses on structure and grain size in AF layer and texture. A direct correlation between the <1 1 1> texture and exchange coupling was found. A direct relation between average grain size and H{sub ex} and H{sub c} was not observed. L1{sub 2} phase IrMn{sub 3} was formed by deposition at room temperature for Ta (5-6 nm)/NiFe (6-8 nm). We conclude that the coercivity is influenced by order/disorder at NiFe/IrMn/CoFe interfaces.

Investigation of the morphology and electrical characteristics of FeSi2 quantum dots on silicon

International Nuclear Information System (INIS)

Dozsa, L.; Molnar, G.; Horvath, Zs.J.; Toth, A.L.; Gyulai, J.; Raineri, V.; Giannazzo, F.

2004-01-01

β-FeSi 2 quantum dots (QD) were grown by evaporating 2, 4 and 7 nm Fe onto Si(1 0 0) wafers and in situ annealed at 600 deg. C for 10 min. QDs were grown also by reactive deposition epitaxy (RDE) evaporating 2 nm Fe onto a 600 deg. C Si substrate and annealed further for 5 min. MIS structures were prepared by evaporating SiO x over the QDs and Al dots on the oxide. The SEM investigations show the density of the QDs is about 10 10 cm -2 in the 2 and 4 nm Fe samples, and it increases to about 3x10 11 cm -2 in the 7 nm Fe sample. The nanoscope investigation shows well resolved QDs only in the 7 nm Fe samples, but their density and size do not allow individual characterization of the QDs by scanning capacitance microscopic measurements. In the RDE samples the QDs are small and irregular, indicating the need for thicker Fe layer. Capacitance-voltage (C-V) measurements show point defects generated by silicidation which compensate the silicon doping (2x10 15 cm -3 ) in about 1 μm depth. C-V results show that in the RDE samples less point defect are generated, their concentration is lower than doping of the Si wafers. The electrical characteristics of MIS structures show that the room temperature deposited iron degrades the I-V characteristics, and induces leakage

Investigation on magnetic properties of orientated nanocomposite Pr2Fe14B/α-Fe permanent magnets by micromagnetic finite-element method

International Nuclear Information System (INIS)

He, Shu-li; Zhang, Hong-wei; Rong, Chuan-bing; Chen, Juan; Sun, Ji-rong; Shen, Bao-gen

2012-01-01

Demagnetization curves for nanocomposite Pr 2 Fe 14 B/α-Fe permanent magnets with different hard grain alignment are calculated by a micromagnetic finite-element method. The results show that both remanence and coercivity increase with improving hard grains alignment. The demagnetization curves show a single-phase demagnetization behavior for the samples with grain size d of 10 nm and two-phase behavior for the samples with d of 20 and 30 nm. H ex (reflecting the magnetic hardening of α-Fe) and H irr (expressing the irreversible reversal of hard phase) are both enhanced with improving the hard grain alignment. The magnetic reversal in orientated nanocomposite permanent magnets is mainly controlled by inhomogeneous pinning of the nucleated type. - Highlights: ► The magnetic properties of nanocomposite Pr 2 Fe 14 B/α-Fe permanent magnets with different hard grains alignment are investigated by micromagnetic finite-element method. ► The calculated results show that both remanence and coercivity increase with improving hard grains alignment. ► Highly ordered orientation of hard phase is the critical factor to improve the properties of nanocomposites.

Gas phase synthesis of core-shell Fe@FeO{sub x} magnetic nanoparticles into fluids

Energy Technology Data Exchange (ETDEWEB)

Aktas, Sitki, E-mail: aksitki61@gmail.com; Thornton, Stuart C.; Binns, Chris [University of Leicester, Department of Physics and Astronomy (United Kingdom); Denby, Phil [Ensol As, Nesttun (Norway)

2016-12-15

Sorbitol, short chain molecules, have been used to stabilise of Fe@FeO{sub x} nanoparticles produced in the gas phase under the ultra-high vacuum (UHV) conditions. The sorbitol coated Fe@FeO{sub x} nanoparticles produced by our method have a narrow size distribution with a hydrodynamic diameter of 35 nm after NaOH is added to the solution. Magnetisation measurement shows that the magnetic nanoparticles are superparamagnetic at 100 K and demonstrate hysteresis at 5 K with an anisotropy constant of 5.31 × 10{sup 4} J/m{sup 3} (similar to bulk iron). Also, it is shown that sorbitol is only suitable for stabilising the Fe@FeO{sub x} suspensions, and it does not prevent further oxidation of the metallic Fe core. According to MRI measurement, the nanoparticles have a high transverse relaxation rate of 425 mM{sup −1} s{sup −1}.

La imagen profesional del bibliotecario escolar la percepción de los directivos y la autopercepción de los bibliotecarios de las escuelas primarias de la ciudad de Rafaela, Santa Fe The School Librarian's Professional Image: The Perception of Headmasters and Self-Perceptions of Librarians in Primary Schools in The City of Rafaela, Santa Fe

Directory of Open Access Journals (Sweden)

Fabiana María Jaime

2012-12-01

Full Text Available Se analiza la imagen profesional del bibliotecario escolar desde la percepción de los directivos y la autopercepción de los bibliotecarios de las escuelas primarias de la ciudad de Rafaela, Santa Fe. De allí se desprenden, como objetivos específicos, analizar la formación profesional del bibliotecario, la imagen ante la sociedad, el rol específico actual, la comunicación con los directivos de escuela, el interés de estos por la función del bibliotecario escolar, la relación con toda la comunidad educativa y las políticas bibliotecarias que rigen el trabajo bibliotecario. Se trata de un estudio crítico descriptivo, con un enfoque cuantitativo. El procedimiento metodológico utilizado es el empírico-deductivo. El universo y la población de estudio, son diez escuelas de la ciudad de Rafaela con bibliotecarios de cargo oficial y título profesional. Se concluye que la imagen que los directivos poseen de los bibliotecarios escolares está desdibujada. Reconocen la capacidad profesional de los bibliotecarios escolares pero no les ofrecen el acompañamiento y las herramientas imprescindibles para desplegar su máximo potencial. Sin embargo, los bibliotecarios fortalecen esta imagen debilitada. De igual modo, la inestabilidad en la implementación de políticas bibliotecarias desde la institución escolar y la carencia de figura legal de bibliotecario escolar para el Estado no brindan oportunidad para reforzar la imagen profesional del bibliotecario escolar.This work examines the professional image of school librarian of the city of Rafaela, Santa Fe. Their specific objectives are to analyse the training of librarians, the image in society, the specific role today, the communication with school headmasters, their interest in the role of school librarian, the relationship with all the educational community and library policies governing library work. This is a critical descriptive and quantitative approach and a design field that extracts

Visible and IR photoluminescence of c-FeSi@a–Si core–shell nano-fibres produced by vapour transport

Energy Technology Data Exchange (ETDEWEB)

Thabethe, Sibongiseni [DST/CSIR National Centre for Nano-Structured Materials, PO Box 395, Pretoria 0001 (South Africa); Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Linganiso, Ella; Motaung, David; Mashapa, Matete G.; Nkosi, Steven [DST/CSIR National Centre for Nano-Structured Materials, PO Box 395, Pretoria 0001 (South Africa); Arendse, Christopher J. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Mwakikunga, Bonex W., E-mail: bmwakikunga@csir.co.za [DST/CSIR National Centre for Nano-Structured Materials, PO Box 395, Pretoria 0001 (South Africa); Department of Physics and Biochemical Sciences, University of Malawi, The Polytechnic, Private Bag 303, Chichiri, Blantyre 3 (Malawi)

2013-11-15

The procedures for the synthesis of amorphous ε-FeSi/Si core–shell nanofibres by vapour transport in a CVD configuration are reported. Crystallite studies by the Williamson-Hall method show the sizes to be typically about 8.0 nm which agrees with TEM value of 7.9 nm fibre diameter with a compressive strain of about 0.04. Features in the photoluminescence of these FeSi core–shells in both visible and IR are at 410 nm, 1062 nm, 1414 nm and 1772 nm and absorption feature at 1000 cm{sup −1} from FTIR are explained from density functional theory (DFT) ab initio calculations. PL confirms the intra-band transition whereas FTIR agrees perfectly with the band-to-band transition whose band gap energy is 0.13 eV for FeSi. FTIR also unveils inter-band transition which DFT calculation could not predict. Raman spectroscopy data confirm FeSi and nano-Si presence. -- Highlights: • New PL data has been obtained for the c-FeSi@a–Si nano-fibres in the range (0.7–3.1 eV). • FTIR unveils the band-to-band transition within this narrow band gap FeSi. • The new data are explained through electronic energy band structure and density of states of FeSi. • Intra-band transitions as well as quantum confinement are responsible for blue shifts.

Colorimetric determination of Fe2+/Fe3+ ratio in radioactive glasses

International Nuclear Information System (INIS)

Coleman, C.J.; Baumann, E.W.; Bibler, N.E.

1992-01-01

In the vitrification of nuclear wastes, the Fe 2+ /Fe 3+ ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe 2+ /Fe 3+ ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that will be produced in the Savannah River Site Defense Waste Processing Facility. The first step of the method is dissolution of finely crushed glass with a hydrofluoric/sulfuric acid mixture with ammonium vanadate added to preserve the Fe 2+ content of the glass during the dissolution. Boric acid is then added to complex fluoride and to destroy iron-fluoride complexes. After adjusting the solution to pH 5, FerroZine TM (trademark of the Hach Company, Loveland, CO) reagent is added to form a magenta-colored complex with Fe 2+ . The absorbance at 562 nm is measured by using a fiber optic-coupled photodiode array spectrophotometer. Ascorbic acid is then used to reduce all the iron in solution to Fe 2+ and the absorbance is again measured. The difference in absorbance measurements corresponds to the Fe 3+ in the sample and the Fe 2+ /Fe 3+ ratio can be calculated

Smooth and rapid microwave synthesis of MIL-53(Fe) including superparamagnetic γ-Fe2O3 nanoparticles

Science.gov (United States)

Wengert, Simon; Albrecht, Joachim; Ruoss, Stephen; Stahl, Claudia; Schütz, Gisela; Schäfer, Ronald

2017-12-01

MIL-53(Fe) linked to superparamagnetic γ-Fe2O3 nanoparticles was created using time-efficient microwave synthesis. Intermediates as well as the final product have been characterized by Dynamic Light Scattering (DLS), Infrared Spectroscopy (FTIR) and Thermal Gravimetric Analysis (TGA). It is found that this route allows the production of Fe nanoparticles with typical sizes of about 80 nm that are embedded inside the metal-organic structures. Detailed magnetization measurements using SQUID magnetometry revealed a nearly reversible magnetization loop indicating essentially superparamagnetic behavior.

Moessbauer and XRD study of pulse plated Fe-P and Fe-Ni thin layers

Energy Technology Data Exchange (ETDEWEB)

Miko, Annamaria [Bay Zoltan Institute for Material Science (Hungary); Kuzmann, Erno, E-mail: kuzmann@para.chem.elte.hu [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Lakatos-Varsanyi, Magda [Bay Zoltan Institute for Material Science (Hungary); Kakay, Attila [Research Institute for Solid State Physics and Optics (Hungary); Nagy, Ferenc [Eoetvoes Lorand University, Research Group for Nuclear Methods in Structural Chemistry, Hungarian Academy of Sciences, Department of Nuclear Chemistry (Hungary); Varga, Lajos Karoly [Research Institute for Solid State Physics and Optics (Hungary)

2005-09-15

{sup 57}Fe conversion electron Moessbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe-P and Ni-Fe coatings. XRD and {sup 57}Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe-P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe-P deposits pulse plated at medium long deposition time (t{sub on} = 2 ms), with short relaxation time (t{sub off} = 9 ms) and low current density (I{sub p} = 0.05 Acm{sup -2}) or at short deposition time (t{sub on} = 1 ms) with long relaxation time (t{sub off} = 250 ms) and high current density (I{sub p} = 1.0 Acm{sup -2}). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni-Fe alloy with a very fine, 5-8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni-Fe and Fe-P pulse plated thin layers.

Orientation and magnetic properties of the thick multilayered [NdFeBxTby]n films

International Nuclear Information System (INIS)

Liu, Weifang; Suzuki, Shunji; Machida, Kenichi

2007-01-01

Multilayered [NdFeB x /Tb y ] n films were prepared by a three-demensional sputtering system. From the thickness of NdFeB layer dependence on the orientation and magnetic properties of multilayered [NdFeB (xμm)/Tb (50nm)] n films with 7.2μm as a total thickness of NdFeB layers, it was found that the orientation of NdFeB grains was maintained. However, the coercivity was enhanced with decreasing the thickness of each NdFeB thin layer. The (BH) max value of 240kJ/m 3 was obtained on the layered [NdFeB (1.2μm)/Tb (50 nm)] 6 film as an optimal value. For the multilayered [NdFeB (1.2μm)/Tb (50 nm)] n films with various multiple layer sets (n), the coercivity value increased with the film thickness without any deterioration of the c-axis texture and consequently, multilayered NdFeB/Tb film magnets with total thickness values around 70μm showed the superior magnetic properties (H cj approx. = 1360kA/m, I r approx.= 1.05T, and (BH) max approx.= 202kJ/m 3 ). (author)

Structural and magnetic properties of CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell nanocomposite prepared by the hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Sattar, A.A. [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); EL-Sayed, H.M., E-mail: h_m_elsaid@hotmail.com [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); ALsuqia, Ibrahim [Department of Physics, Faculty of Education and Applied Science, Hajjah University, Alshahli, Hajjah (Yemen)

2015-12-01

CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell magnetic nanocomposite was synthesized by using hydrothermal method.The analysis of XRD indicated the coexistence of CoFe{sub 2}O{sub 4}, NiFe{sub 2}O{sub 4}as core/shell composite. The core/shell structure of the composite sample has been confirmed by HR-TEM images, EDX and FT-IR measurements. The size of obtained core/shell nanoparticles was 17 nm in core diameter and about 3 nm in shell thickness. The magnetization measurements showed that both the coercive field and the saturation magnetization of the resulting core/shell nanocomposite were slightly decreased compared to those of the CoFe{sub 2}O{sub 4} core but the thermal stability is of the magnetization parameter was enhanced. Furthermore, superparamagnetic phase is established at temperatures higher than the room temperature. The results were discussed in terms of the surface pinning and the magnetic interaction at the interface between the core and shell. - Highlights: • CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell could be prepared by hydrothermal method. • The structural analysis proved the formation of NiFe{sub 2}O{sub 4} shell with thickness 3 nm. • The thermal stability of M{sub s} and H{sub c} is enhanced due to the presence of NiFe{sub 2}O{sub 4} as a shell. • Super paramagnetic transition is confirmed and the effective magnetic anisotropy was calculated.

New carbazole-based Schiff base: Colorimetric chemosensor for Fe{sup 3+} and fluorescent turn-on chemosensor for Fe{sup 3+} and Cr{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Zhu, Weiju; Yang, Lianlian; Fang, Min; Wu, Zhenyu; Zhang, Qing; Yin, Fangfang; Huang, Qiang; Li, Cun, E-mail: cun_li@126.com

2015-02-15

Two novel carbazole-based Schiff-bases L1 and L2 have been synthesized and characterized by {sup 1}H NMR, {sup 13}C NMR, FT-IR spectroscopy and elemental analysis. L1 can selectively detect Fe{sup 3+} by UV–vis spectroscopy and Fe{sup 3+}/Cr{sup 3+} by fluorescent spectroscopy in CH{sub 3}CN among various metal ions. The addition of Fe{sup 3+} ions to a L1 solution results in a significant blue-shift from 410 nm to 378 nm accompanied with color change from yellowish green to colorless. Upon excitation at 380 nm, the addition of Fe{sup 3+} or Cr{sup 3+} causes a 13-fold or 11-fold fluorescence enhancement. The binding stoichiometry ratio of L1–Fe{sup 3+} and L1–Cr{sup 3+} is recognized as 2:1 by the method of Job's plot, and the possible binding mode of the system also proposes. The results indicate that L1 is an ideal chemosensor for Fe{sup 3+} and Cr{sup 3+} recognition. However, L2 without hydroxyl in ortho imino group cannot selectively recognize the tasted metal ions, indicating that the introduction of the appropriate coordination binding site to receptor can improve efficiently the selectivity of chemosensor. - Highlights: • We designed and synthesized two new carbazole-based Schiff bases L1 and L2. • L1 could selectively recognize Fe{sup 3+} but L2 could not, which suggested that increase recognition site helped to improve the selectivity of probe. • L1 not only could serve as a highly selective visual chemosensor for Fe{sup 3+} ion without the aid of any instruments, but also could be used as a fluorescent chemosensor for Fe{sup 3+} and Cr{sup 3+}.

Nanocrystalline Fe-Pt alloys. Phase transformations, structure and magnetism

Energy Technology Data Exchange (ETDEWEB)

Lyubina, J.V.

2006-12-21

This work has been devoted to the study of phase transformations involving chemical ordering and magnetic properties evolution in bulk Fe-Pt alloys composed of nanometersized grains. Nanocrystalline Fe{sub 100-x}Pt{sub x} (x=40-60) alloys have been prepared by mechanical ball milling of elemental Fe and Pt powders at liquid nitrogen temperature. The as-milled Fe-Pt alloys consist of {proportional_to} 100 {mu}m sized particles constituted by randomly oriented grains having an average size in the range of 10-40 nm. Depending on the milling time, three major microstructure types have been obtained: samples with a multilayer-type structure of Fe and Pt with a thickness of 20-300 nm and a very thin (several nanometers) A1 layer at their interfaces (2 h milled), an intermediate structure, consisting of finer lamellae of Fe and Pt (below approximately 100 nm) with the A1 layer thickness reaching several tens of nanometers (4 h milled) and alloys containing a homogeneous A1 phase (7 h milled). Subsequent heat treatment at elevated temperatures is required for the formation of the L1{sub 0} FePt phase. The ordering develops via so-called combined solid state reactions. It is accompanied by grain growth and thermally assisted removal of defects introduced by milling and proceeds rapidly at moderate temperatures by nucleation and growth of the ordered phases with a high degree of the long-range order. In a two-particle interaction model elaborated in the present work, the existence of hysteresis in recoil loops has been shown to arise from insufficient coupling between the low- and the high-anisotropy particles. The model reveals the main features of magnetisation reversal processes observed experimentally in exchange-coupled systems. Neutron diffraction has been used for the investigation of the magnetic structure of ordered and partially ordered nanocrystalline Fe-Pt alloys. (orig.)

Morphology-controlled synthesis of α-FeOOH and its derivatives

International Nuclear Information System (INIS)

Sun Zhengzong; Feng Xiaomiao; Hou Wenhua

2007-01-01

α-FeOOH nanocrystals were synthesized in high yield via a facile and template-free hydrothermal method at low temperature. The morphology and composition of the samples were controlled by slowly releasing the SO 4 2- ions from ammonium persulfate. The rod-like, bundle-like, and urchin-like α-FeOOH nanocrystals could be acquired respectively through a direct hydrothermal route with different quantities of SO 4 2- ions. The rod-like α-FeOOH nanocrystals obtained have a diameter of 5-25 nm and a length of 100-200 nm. When the molar ratio of iron to SO 4 2- was 1:1, the product was pure α-FeOOH phase. However, as the molar ratio was decreased from 1:1 to 1:4, pure FeSO 4 OH·2H 2 O phase was obtained. When the molar ratio was between 1:4 and 1:1, the prepared product was composed of two phases (α-FeOOH and FeSO 4 OH·2H 2 O). After hydrothermally aging the as-synthesized α-FeOOH nanorods at 180 deg. C for 1 d, α-Fe 2 O 3 nanorods were obtained. However, the edge of the α-Fe 2 O 3 nanorods was sword-like and different from the blunt edge of α-FeOOH nanorods due to a recrystallization mechanism

Thermal decomposition of barium ferrate(VI): Mechanism and formation of Fe{sup IV} intermediate and nanocrystalline Fe{sub 2}O{sub 3} and ferrite

Energy Technology Data Exchange (ETDEWEB)

Machala, Libor, E-mail: libor.machala@upol.cz [Regional Centre of Advanced Technologies and Materials, Department of Experimental Physics, Faculty of Science, Palacký University, Olomouc (Czech Republic); Sharma, Virender K. [Department of Environmental and Occupational Health, School of Public Health, Texas A& M University, 1266 TAMU, College Station, TX 77843 (United States); Kuzmann, Ernö; Homonnay, Zoltán [Institute of Chemistry, Eötvös Loránd University, Budapest (Hungary); Filip, Jan; Kralchevska, Radina P. [Regional Centre of Advanced Technologies and Materials, Department of Experimental Physics, Faculty of Science, Palacký University, Olomouc (Czech Republic)

2016-05-25

Simple high-valent iron-oxo species, ferrate(VI) (Fe{sup VI}O{sub 4}{sup 2−}, Fe(VI)) has applications in energy storage, organic synthesis, and water purification. Of the various salts of Fe(VI), barium ferrate(VI) (BaFeO{sub 4}) has also a great potential as a battery material. This paper presents the thermal decomposition of BaFeO{sub 4} in static air and nitrogen atmosphere, monitored by combination of thermal analysis, Mössbauer spectroscopy, X-ray powder diffraction, and electron-microscopic techniques. The formation of Fe{sup IV} species in the form of BaFeO{sub 3} was found to be the primary decomposition product of BaFeO{sub 4} at temperature around 190 °C under both studied atmospheres. BaFeO{sub 3} was unstable in air reacting with CO{sub 2} to form barium carbonate and speromagnetic amorphous iron(III) oxide nanoparticles (<5 nm). Above 600 °C, a solid state reaction between BaCO{sub 3} and Fe{sub 2}O{sub 3} occurred, leading to the formation of barium ferrite nanoparticles, BaFe{sub 2}O{sub 4} (20–100 nm). - Highlights: • We explained the mechanism of thermal decomposition of barium ferrate(VI). • We confirmed the formation of Fe(IV) intermediate phase during the decomposition. • The mechanism of the decomposition is influenced by a presence of carbon dioxide.

Interfacial magnetic coupling between Fe nanoparticles in Fe–Ag granular alloys

International Nuclear Information System (INIS)

Alonso, J; Fdez-Gubieda, M L; Sarmiento, G; Chaboy, J; Boada, R; García Prieto, A; Haskel, D; Laguna-Marco, M A; Lang, J C; Meneghini, C; Fernández Barquín, L; Neisius, T; Orue, I

2012-01-01

The role of the interface in mediating interparticle magnetic interactions has been analysed in Fe 50 Ag 50 and Fe 55 Ag 45 granular thin films deposited by the pulsed laser deposition technique (PLD). These samples are composed of crystalline bcc Fe (2–4 nm) nanoparticles and fcc Ag (10–12 nm) nanoparticles, separated by an amorphous Fe 50 Ag 50 interface, occupying around 20% of the sample volume, as determined by x-ray diffraction (XRD), x-ray absorption spectroscopy (XAS), and high resolution transmission electron microscopy (HRTEM). Interfacial magnetic coupling between Fe nanoparticles is studied by dc magnetization and x-ray magnetic circular dichroism (XMCD) measurements at the Fe K and Ag L 2,3 edges. This paper reveals that these thin films present two magnetic transitions, at low and high temperatures, which are strongly related to the magnetic state of the amorphous interface, which acts as a barrier for interparticle magnetic coupling.

Reciprocidades y gubernamentalidad tras la inserción del dispositivo religioso en cárceles de mediana y máxima seguridad de la provincia de Santa Fe (Argentina

Directory of Open Access Journals (Sweden)

Mauricio Manchado

2016-05-01

Full Text Available En el presente trabajo indagaremos sobre la reconfiguración de las dinámicas institucionales en dos cárceles de la provincia de Santa Fe, Argentina, tras la inserción del dispositivo religiosoevangélico- pentecostal. Los casos serán las penitenciarías n° 3 —mediana seguridad— y n° 11 — máxima seguridad—, y nos interrogaremos sobre las relaciones de reciprocidad que el dispositivo religioso configura en el encierro, en cómo dichas relaciones definen nuevas estrategias de gobierno por parte del servicio penitenciario y de qué manera se rediseñan las relaciones de poder en el dispositivo carcelario. Abordaje comparativo que responde a la hipótesis de que el dispositivo religioso-evangélicopentecostal construye matrices comunes de ordenamiento social, funcionamiento y reciprocidades en el encierro pero, al mismo tiempo, consolida su funcionamiento a raíz de una identificación precisa de las necesidades y oportunidades de los sujetos según atraviesen situaciones de ingreso o egreso carcelario.

Domain wall motions in perpendicularly magnetized CoFe/Pd multilayer nanowire

DEFF Research Database (Denmark)

Meng, Zhaoliang; Kumar, Manoj; Qiu, Jinjun

2014-01-01

Current-induced domain wall (DW) motion is investigated in a 600nm wide nanowire using multilayer film with a structure of Ta(5nm)/Pd(5nm)/[CoFe(0.4nm)/Pd(1.2nm)]15/Ta(5nm) in terms of anomalous Hall effect measurements. It is found that motion of DWs can be driven by a current density as low as 1...

Dos visiones sobre la planificación regional en el final del auge desarrollista: las propuestas de orientación del crecimiento urbano (Santa Fe, Argentina, 1980

Directory of Open Access Journals (Sweden)

Gisela Ariana Rausch

2013-12-01

Full Text Available El desarrollismo de la segunda posguerra -en sus diferentes vertientes- llevó a su máxima expresión el ideal moderno de instrumentalización de la naturaleza como vía del mejoramiento social. En Argentina (como en América Latina, se adoptarían una variedad de prescripciones surgidas, principalmente, de la Comisión Económica para América Latina (CEPAL, mientras la disciplina urbanística sufriría una transformación profunda de sus bases teóricas, produciéndose un pasaje del “Urbanismo” al “planeamiento”. Esto como correlato directo del pasaje de una concepción “jurisdiccional” del territorio de intervención, a otra concepción “regional”. A partir de ello, se expondrán dos propuestas de crecimiento urbano para la ciudad de Santa Fe, una asentada en el desarrollismo tecnocrático, que hizo énfasis en las infraestructuras como medio técnico de control de la naturaleza, y la otra, más híbrida y alternativa, que hizo foco en la especificidad geográfica y cultural santafesina.

Parallel ferromagnetic resonance and spin-wave excitation in exchange-biased NiFe/IrMn bilayers

Energy Technology Data Exchange (ETDEWEB)

Sousa, Marcos Antonio de, E-mail: marcossharp@gmail.com [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Pelegrini, Fernando [Instituto de Física, Universidade Federal de Goiás, Goiânia, 74001-970 (Brazil); Alayo, Willian [Departamento de Física, Universidade Federal de Pelotas, Pelotas, 96010-900 (Brazil); Quispe-Marcatoma, Justiniano; Baggio-Saitovitch, Elisa [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, 22290-180 (Brazil)

2014-10-01

Ferromagnetic Resonance study of sputtered Ru(7 nm)/NiFe(t{sub FM})/IrMn(6 nm)/Ru(5 nm) exchange-biased bilayers at X and Q-band microwave frequencies reveals the excitation of spin-wave and NiFe resonance modes. Angular variations of the in-plane resonance fields of spin-wave and NiFe resonance modes show the effect of the unidirectional anisotropy, which is about twice larger for the spin-wave mode due to spin pinning at the NiFe/IrMn interface. At Q-band frequency the angular variations of in-plane resonance fields also reveal the symmetry of a uniaxial anisotropy. A modified theoretical model which also includes the contribution of a rotatable anisotropy provides a good description of the experimental results.

Size effect on L10 ordering and magnetic properties of chemically synthesized FePt and FePtAu nanoparticles

Science.gov (United States)

Jia, Zhiyong; Kang, Shishou; Shi, Shifan; Nikles, David E.; Harrell, J. W.

2005-05-01

There is growing evidence that FePt nanoparticles become increasingly difficult to chemically order as the size approaches a few nanometers. We have studied the chemical ordering of FePt and FePtAu nanoparticle arrays as a function of particle size. Monodisperse Fe49Pt51 and Fe48Pt44Au8 nanoparticles with a size about 6nm were synthesized by the simultaneous decomposition of iron pentacarbonyl and reduction of platinum acetylacetonate and gold (III) acetate in a mixture of phenyl ether and hexadecylamine (HDA), with 1-adamantanecarboxylic acid and HDA as stabilizers. The nanoparticles were dispersed in toluene, films of the particles were cast onto silicon wafers from the dispersion, and the films were annealed in a tube furnace with flowing Ar +5%H2. The magnetic anisotropy and switching volumes were determined from time- and temperature-dependent coercivity measurements. By comparing with 3-nm FePt and FePtAu nanoparticles of comparable composition, the phase transformation is easier for the larger particles. Under the same annealing conditions, the larger particles have higher anisotropy and order parameter. Additive Au is very effective in enhancing the chemical ordering in both small and large particles, with x-ray diffraction superlattice peaks appearing after annealing at 350°C. Dynamic remnant coercivity measurements and magnetic switching volumes suggest particle aggregation at the higher annealing temperatures in both small and large particles.

Myxomycetes de Florianópolis (Santa Catarina - Brasil Myxomycetes of Florianópolis (State of Santa Catarina - Brazil

Directory of Open Access Journals (Sweden)

Laise de Holanda Cavalcanti

1994-07-01

Full Text Available Considerando a inexistência de registros de ocorrência de Myxomycetes em Florianópolis, realizou- se coletas nas matas da Lagoa do Peri e Lagoa da Conceição, em 1990, assinalando-se as seguintes espécies : Lycogala exiguum Morg. (Enteridiaceae ; Cribraria languescem Rex, C. vulgaris Sclir. (Cribrariaceae ; Arcyria cinerea ( Bull. Pers. , Hemitrichia serpula ( Scop. Rost., H. calyculata ( Speg. Farr e Hemitrichia sp (Trichiaceae ; Stemonitis fusca Roth. e S. smithii Macbr. (Stemonitaceae. Exsicatas encontram-se depositadas no herbário UFP. Lycogala exiguum é assinalada pela primeira vez para Santa Catarina, Cribraria languescens para a região Sul e Cribraria vulgaris para o Brasil. O levantamento eleva para 47 o número de espécies referidas para o Estado de Santa Catarina. Fornece-se um histórico do estudo deste qrupo de organismos em Santa Catarina bem como a área de ocorrência de cada espécie no Estado e nas diferentes regiões do Brasil.A survey on Myxomycetes was made in the woods of Lagoa do Peri and Lagoa da Conceição in 1990, considering the absence of reports of this kind for the city of Florianópolis, when the following species were registered: Lycogala exiguum Morg. (Enteridiaceae; Cribraria languescem Rex, C. vulgaris Schr. (Cribrariaceae; Arcyria cinerea (Bull. Pers. Hemitrichia serpula (Scop. Rost., H. calyculata (Speg. Fair and Hemitrichia sp (Trichiaceae; Stemonitis fusca Roth, and S. smithii Macbr. (Stemonitaceae. Exicates are deposited at the herbarium UFP. Lycogala exiguum is noted for the first time in the state of Santa Catarina, Cribraria languescem in the South and Cribraria vulgaris in Brazil. The survey raises up the number of registers refered to the state of Santa Catarina to 47 species. A review of the studies on this group of organisms in Santa Catarina is given as well as the area where each species occur in this state and in different regions of Brazil.

Ion-irradiation induced chemical ordering of FePt and FePtAu nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Seetala, Naidu V. [Department of Physics, Grambling State University, RWE Jones Drive, Carver Hall 81, Grambling, LA 71245 (United States)]. E-mail: naidusv@gram.edu; Harrell, J.W. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Lawson, Jeremy [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Nikles, David E. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Williams, John R. [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Isaacs-Smith, Tamara [Department of Physics, Auburn University, Auburn, AL 36849 (United States)

2005-12-15

We have studied the effect of ion-beam irradiation on reducing the ordering temperature of FePt and FePtAu nanoparticles. FePt and FePt(Au14%) 4 nm particles dispersed on a Si-substrate were irradiated by 300 keV Al-ions with a dose of 1 x 10{sup 16} ions/cm{sup 2} at 43 {sup o}C using a water-cooled flange in order to minimize the vacancy migration and voids formation within the collision cascades. Partial chemical ordering has been observed in as-irradiated particles with coercivity of 60-130 Oe. Post-irradiation annealing at 220 {sup o}C enhanced chemical ordering in FePt nanoparticles with coercivity of 3500 Oe, magnetic anisotropy of 1.5 x 10{sup 7} erg/cc, and thermal stability factor of 130. A much higher 375 {sup o}C post-irradiation annealing was required in FePtAu, presumably because Au atoms were trapped at Fe/Pt lattice sites at lower temperatures. As the annealing temperature increased, anomalous features in the magnetization reversal curves were observed that disappeared at higher annealing temperatures.

Magnetron-sputter deposition of Fe3S4 thin films and their conversion into pyrite (FeS2) by thermal sulfurization for photovoltaic applications

International Nuclear Information System (INIS)

Liu Hongfei; Chi Dongzhi

2012-01-01

The authors report on the fabrication of FeS 2 (pyrite) thin films by sulfurizing Fe 3 S 4 that were deposited by direct current magnetron sputtering at room temperature. Under the selected sputtering conditions, Fe 3 S 4 nanocrystal films are obtained and the nanocrystals tend to locally cluster and closely pack into ricelike nanoparticles with an increase in film thickness. Meanwhile, the film tends to crack when the film thickness is increased over ∼1.3 μm. The film cracking can be effectively suppressed by an introduction of a 3-nm Cu intermediate layer prior to Fe 3 S 4 deposition. However, an introduction of a 3-nm Al intermediate layer tends to enhance the film cracking. By post-growth thermal sulfurization of the Fe 3 S 4 thin films in a tube-furnace, FeS 2 with high phase purity, as determined by using x ray diffraction, is obtained. Optical absorption spectroscopy was employed to characterize the resultant FeS 2 thin films, which revealed two absorption edges at 0.9 and 1.2 eV, respectively. These two absorption edges are assigned to the direct bandgap (0.9 eV) and the indirect allowed transitions (1.2 eV) of FeS 2 , respectively.

Oxidation states of Fe and Ti in blue sapphire

International Nuclear Information System (INIS)

Wongrawang, P; Wongkokua, W; Monarumit, N; Thammajak, N; Wathanakul, P

2016-01-01

X-ray absorption near-edge spectroscopy (XANES) can be used to study the oxidation state of a dilute system such as transition metal defects in solid-state samples. In blue sapphire, Fe and Ti are defects that cause the blue color. Inter-valence charge transfer (IVCT) between Fe 2+ and Ti 4+ has been proposed to describe the optical color’s origin. However, the existence of divalent iron cations has not been thoroughly investigated. Fluorescent XANES is therefore employed to study K-edge absorptions of Fe and Ti cations in various blue sapphire samples including natural, synthetic, diffused and heat-treated sapphires. All the samples showed an Fe absorption edge at 7124 eV, corresponding to the Fe 3+ state; and Ti at 4984 eV, corresponding to Ti 4+ . From these results, we propose Fe 3+ -Ti 4+ mixed acceptor states located at 1.75 eV and 2.14 eV above the valence band of corundum, that correspond to 710 nm and 580 nm bands of UV–vis absorption spectra, to describe the cause of the color of blue sapphire. (paper)

An environment-friendly microemulsion approach to α-FeOOH nanorods at room temperature

International Nuclear Information System (INIS)

Geng Fengxia; Zhao Zhigang; Cong Hongtao; Geng Jianxin; Cheng Huiming

2006-01-01

α-FeOOH nanorods have been prepared at room temperature by an environment-friendly microemulsion approach. X-ray diffraction and transmission electron microscopy revealed that the single-crystalline orthorhombic α-FeOOH nanorods are 8.2 ± 1.5 nm in diameter and 106 ± 16 nm in length. Furthermore, the mechanism for the formation of α-FeOOH nanorods is preliminarily presented. This method may be widely used for reference to fabricate other inorganic one-dimensional nanostructured materials and easily realized in industrial-scale synthesis

Microstructure, magnetic and Moessbauer studies on spark-plasma sintered Sm-Co-Fe/Fe(Co) nanocomposite magnets

Energy Technology Data Exchange (ETDEWEB)

Rao, N V Rama; Saravanan, P; Gopalan, R; Raja, M Manivel; Rao, D V Sreedhara; Chandrasekaran, V [Defence Metallurgical Research Laboratory, Hyderabad-500 058 (India); Sivaprahasam, D [International Advanced Research Centre for Powder Metallurgy and New Materials Hyderabad-500 005 (India); Ranganathan, R [Saha Institute of Nuclear Physics, Kolkata-700 064 (India)], E-mail: rg_gopy@yahoo.com

2008-03-21

Nanocomposite powders comprising Sm-Co-Fe intermetallic phases and Fe(Co) were synthesized by high-energy ball milling and were consolidated into bulk magnets by the spark-plasma sintering (SPS) technique. While the microstructure of the SPS samples was characterized by transmission electron microscopy (TEM), the solubility of Fe in different phases was investigated using Moessbauer spectroscopy. TEM studies revealed that the spark-plasma sintered sample has Sm(Co,Fe){sub 5} as a major phase with Sm{sub 2}(Co,Fe){sub 17}, Sm(Co,Fe){sub 2} and Fe(Co) as secondary phases. The size of the nanocrystalline grains of all these phases was found to be in the range 50-100 nm. The Moessbauer spectra of the as-milled powders exhibited two different subspectra: a sextet corresponding to the Fe phase and a broad sextet associated with the Fe(Co) phase; while that of the SPS sample showed four different subspectra: a sextet corresponding to Fe and other three sextets corresponding to the Fe(Co), Sm(Co,Fe){sub 5} and Sm{sub 2}(Co,Fe){sub 17} phases; these results are in accordance with the TEM observation. Recoil magnetization and reversible susceptibility measurements revealed magnetically single phase behaviour of the SPS magnets.

Pr2Fe14B/α-Fe nanocomposites for thermal applications

International Nuclear Information System (INIS)

Silva, Suelanny Carvalho da

2012-01-01

In this work, Pr x Fe 94 - x B 6 (x = 6, 8, 10 and 12) nanostructured powders were prepared by a combination of hydrogenation, disproportionation, desorption and recombination (HDDR) process with high energy milling applied to the mixture of an as-cast alloy (Pr 14 Fe 80 B 6 ) and α-Fe. The produced nanoparticles showed magnetic properties comparable to those reported in hyperthermia studies. The optimal time to obtain the magnetic nanoparticles is 5 hours (at 900 rpm). It was verified that longer milling times cause an increase in carbon percentage on the particles. The carbon is derived from oleic acid added as a surfactant in the milling step. The nanocomposites exhibit coercive force ranging from 80 Oe (6.5 kAm -1 ) to 170 Oe (13.5 kAm -1 ) and magnetic moments in the range of 81 129 Am2kg -1 . From the X-ray diffraction analyses, only two phases were found in all samples: α-Fe and the magnetic phase Pr 2 Fe 14 B. Individual nanoparticles with diameter of about 20 nm were verified. The samples studied presented heating when exposed to an alternating magnetic field (f = 222 kHz e H max ∼3.7 kAm -1 ) comparable to reported in literature. Temperature variations (ΔT) of the powders were: 51 K for Pr 6 Fe 88 B 6 , 41 K for Pr 8 Fe 86 B 6 , 38 K for Pr 10 Fe 8 4 B 6 and T = 34 K for Pr 12 Fe 82 B 6 . The specific absorption rates (SARs) of the powders were 201 Wkg -1 for Pr 6 Fe 88 B 6 composition, 158 Wkg -1 on the composition Pr 8 Fe 86 B 6 , and 114 Wkg -1 for Pr 10 Fe 84 B 6 and Pr 12 Fe 82 B 6 compositions. (author)

Channel and hillslope processes revisited in the Arroyo de los Frijoles watershed near Santa Fe, New Mexico

Science.gov (United States)

Gellis, Allen C.; Emmett, William W.; Leopold, Luna Bergere

2005-01-01

Detailed documentation of geomorphic changes in the landscape of more than a few years is rarely possible. Channel cross sections, channel profiles, sediment deposition behind dams, and hillslope-erosion plots, originally benchmarked within several watersheds outside Santa Fe, New Mexico, in the 1950’s and 1960’s, for a 1966 report that documented processes and rates of arid-region sediment production and deposition, were resurveyed in the mid-1990’s. Many of the original study sites were relocated and surveyed in the mid-1990’s to determine subsequent channel and hillslope changes and to determine whether trends of channel and hillslope aggradation and degradation that were evident in the 1950’s and 1960’s have continued. In general, the net change in channel geometry has been small over the last 30–40 years. The average change in cross-sectional area of 32 resurveyed cross sections was erosion of 0.27 square meter, which equates to a 4-percent increase in cross-sectional area. The average net change in thalweg elevation for 51 resurveyed cross sections was degradation of 0.04 meter. Unpublished data (1964–68) from the scour chains showed that 371 chains had an average scour of 0.14 ± 0.14 meter and that 372 chains showed an average fill of 0.13 + 0.11 meter. Scour, found in the original study (1958–64) to be proportional to the square root of discharge, was confirmed with the addition of unpublished data (1964–68). The observed channel changes have no consistent trend, compared either to results observed in the original 1966 study or to distance from the watershed divide. The conclusion drawn in the original study was that most channels were aggrading; the resurvey showed that aggradation did not continue.An increase in housing and population in the Arroyo de los Frijoles watershed since the 1950’s has led to more roads. Channel degradation is most noticeable at road crossings. The greatest degradation of the main channel Arroyo de los

Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2006-01-01

The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

Optical and magneto-optical characterization of TbFeCo and GdFeCo thin films for high-density recording

International Nuclear Information System (INIS)

Hendren, W R; Atkinson, R; Pollard, R J; Salter, I W; Wright, C D; Clegg, W W; Jenkins, D F L

2003-01-01

Thin, optically semi-infinite films of amorphous TbFeCo and GdFeCo, suitable for magneto-optical recording, have been deposited by DC magnetron sputtering onto glass. Ellipsometric techniques have been used to determine the complex refractive index and complex magneto-optical parameter of the films in the wavelength range 400-900 nm, thus characterizing the materials. A review of the literature is presented and shows that the results for the TbFeCo films compare favourably with published results obtained from measurements conducted in situ, with the films protected with ZnS barrier layers. It is found that GdFeCo and TbFeCo are optically very similar, but magneto-optically the materials are quite different

Optical and magneto-optical characterization of TbFeCo and GdFeCo thin films for high-density recording

Energy Technology Data Exchange (ETDEWEB)

Hendren, W R [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Atkinson, R [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Pollard, R J [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Salter, I W [Department of Pure and Applied Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Wright, C D [School of Engineering and Computer Science, University of Exeter, Exeter EX4 4QF (United Kingdom); Clegg, W W [CRIST, University of Plymouth, Plymouth PL4 8AA (United Kingdom); Jenkins, D F L [CRIST, University of Plymouth, Plymouth PL4 8AA (United Kingdom)

2003-03-12

Thin, optically semi-infinite films of amorphous TbFeCo and GdFeCo, suitable for magneto-optical recording, have been deposited by DC magnetron sputtering onto glass. Ellipsometric techniques have been used to determine the complex refractive index and complex magneto-optical parameter of the films in the wavelength range 400-900 nm, thus characterizing the materials. A review of the literature is presented and shows that the results for the TbFeCo films compare favourably with published results obtained from measurements conducted in situ, with the films protected with ZnS barrier layers. It is found that GdFeCo and TbFeCo are optically very similar, but magneto-optically the materials are quite different.

Magnetic interaction reversal in watermelon nanostructured Cr-doped Fe nanoclusters

International Nuclear Information System (INIS)

Kaur, Maninder; Qiang, You; Dai, Qilin; Tang, Jinke; Bowden, Mark; Engelhard, Mark; Wu, Yaqiao

2013-01-01

Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr ( 2 O 3 and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (∼25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of σ-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs

Role of the antiferromagnetic pinning layer on spin wave properties in IrMn/NiFe based spin-valves

Energy Technology Data Exchange (ETDEWEB)

Gubbiotti, G., E-mail: gubbiotti@fisica.unipg.it; Tacchi, S. [Istituto Officina dei Materiali del CNR (IOM-CNR), Unità di Perugia, I-06123 Perugia (Italy); Del Bianco, L. [Department of Physics and Astronomy, University of Bologna, I-40127 Bologna (Italy); Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Bonfiglioli, E.; Giovannini, L.; Spizzo, F.; Zivieri, R. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia (Italy)

2015-05-07

Brillouin light scattering (BLS) was exploited to study the spin wave properties of spin-valve (SV) type samples basically consisting of two 5 nm-thick NiFe layers (separated by a Cu spacer of 5 nm), differently biased through the interface exchange coupling with an antiferromagnetic IrMn layer. Three samples were investigated: a reference SV sample, without IrMn (reference); one sample with an IrMn underlayer (10 nm thick) coupled to the bottom NiFe film; one sample with IrMn underlayer and overlayer of different thickness (10 nm and 6 nm), coupled to the bottom and top NiFe film, respectively. The exchange coupling with the IrMn, causing the insurgence of the exchange bias effect, allowed the relative orientation of the NiFe magnetization vectors to be controlled by an external magnetic field, as assessed through hysteresis loop measurements by magneto-optic magnetometry. Thus, BLS spectra were acquired by sweeping the magnetic field so as to encompass both the parallel and antiparallel alignment of the NiFe layers. The BLS results, well reproduced by the presented theoretical model, clearly revealed the combined effects on the spin dynamic properties of the dipolar interaction between the two NiFe films and of the interface IrMn/NiFe exchange coupling.

Magnetization reversal and coercivity of Fe3Se4 nanowire arrays

Science.gov (United States)

Li, D.; Li, S. J.; Zhou, Y. T.; Bai, Y.; Zhu, Y. L.; Ren, W. J.; Long, G.; Zeng, H.; Zhang, Z. D.

2015-05-01

The microstructure and magnetic properties of Fe3Se4 nanowire (NW) arrays in anodic aluminum oxide (AAO) porous membrane are studied. Cross-sectional SEM and plane-view TEM images show that the mean wire diameter (dw) and the center-to-center spacing (D) of Fe3Se4 nanowires are about 220 nm and 330 nm, respectively. The field-cooled magnetization dependent on the temperature indicates a Curie temperature around 334 K for the Fe3Se4 nanowires. The coercivities of Fe3Se4 nanowires at 10 K, obtained from the in-plane and out-of-plane hysteresis loops, are as high as 22.4 kOe and 23.3 kOe, which can be understood from the magnetocrystalline anisotropy and the magnetization reversal process.

LA INFORMACIÓN ETNOGRÁFICA Y ETNOLÓGICA COMO MARCO INTERPRETATIVO PARA CONTEXTOS ZOOARQUEOLÓGICOS EN LA LLANURA ALUVIAL DEL PARANÁ (SANTA FE, ARGENTINA / The ethnographic and ethnologic information as interpretative framework for zooarchaeological ...

Directory of Open Access Journals (Sweden)

Julieta Isabel Sartori

2015-12-01

Full Text Available En este trabajo se presenta información histórica proveniente de diferentes documentos escritos, los cuales fueron producidos por viajeros que estuvieron en el nuevo continente durante los S XVI y XVII. Los mismos otorgan datos acerca de la subsistencia de cazadores-recolectores-pescadores que habitaban la llanura aluvial del Paraná (centro-este de la actual provincia de Santa Fe, así como también sectores aledaños (como en el Gran Chaco y Buenos Aires, Argentina.Por otra parte también se hace referencia a investigaciones etnográficas sobre grupos de momentos históricos y actuales. En todos los casos el hincapié está puesto en aquellos grupos cuyo tipo de subsistencia podría ser comparable con la de quienes habitaron el área de interés en el pasado pre-europeo. Teniendo en cuenta los distintos tipos de registros a considerar aquí, el objetivo de este trabajo es analizar si la información que refiere a la explotación de los recursos faunísticos es útil para proporcionar marcos de referencia más amplios para las interpretaciones arqueológicas de un sector de la llanura aluvial del Paraná. AbstractIn this paper we develop historic information provide for different writings, which were produce by explorers that stay in the new continent during XVI and XVIII centuries. These documents give data about subsistence of hunter-gatherers that inhabit the Alluvial Plain of the Paraná River (east-center of Santa Fe and adjacent sectors (i.e. Gran Chaco y Buenos Aires, Argentina.In addition, we also make references about the ethnographical researches for current and historical groups. In all cases we emphasis those which subsistence could be comparable with the hunter-gatherers that lived in the area under studied. Considering the different types of works that we refer, we aim to analyze if the information about the exploitation of fauna resources is useful to provide a frame of reference to archaeological interpretations in the

Ferromagnetic resonance on oxideless magnetic Fe and FeRh nanoparticles

International Nuclear Information System (INIS)

Trunova, Anastasia

2009-01-01

This work is dedicated to investigations of structural and magnetic properties of the colloidal Fe/Fe x O y nanocubes (13 nm) and the Fe x Rh 100-x core/shell nanoparticles (2 nm). As compared with other works, where the measurements on oxidized nanoparticles were carried out, we additionally performed investigations on nanoparticles in an oxide free state. In order to make the measurements on oxide free particles possible, oxygen- and hydrogenplasma was used to remove the ligands and reduce the oxide shell of the Fe nanocubes. The oxide free Fe nanocubes were covered with a Ag/Pt protective coating to prevent them from new oxidation. This method allowed carrying out the magnetic measurements on oxide free Fe nanocubes. Micromagnetic simulations as well as simulations of the high frequency susceptibility were used for the data analysing. It was found that both the g-factor g=2.09±0.01 and the anisotropy constant K 4 =(4.8±0.5).10 4 J/m 3 coincide with that of bulk iron. However, the saturation magnetization M S (5 K)=(1.2±0.12).10 6 A/m differs from the bulk value by 30%. The reduction by 30% compared to the bulk value in the case of nanoparticles may be caused by the following possible reasons: a) the presence of inner oxide layer (approx. 10 at.%) that cannot be reduced; b) the anti-parallel order between magnetic moments of iron core and magnetic moments of antiferomagnetic iron oxide; c) some structural changes of the surface after plasma treatment. The obtained damping parameter α=0.03±0.005 is ten times larger than that of the Fe layers as it is known for nanoparticles systems in general. The core/shell Fe x Rh 100-x nanoparticles (x=80,50) were produced under Ar-atmosphere and were sealed into a quartz tube to prevent oxidation. The analysis of g-factors shows that the value for the FePh nanoparticles with Fe-rich core is larger (g=2.08±0.01) than that for the nanoparticles with Rh-rich core and coincides within error bars with the g-factor of bulk

Structural and magnetic properties of Gd/Fe multilayers grown by pulsed laser deposition

DEFF Research Database (Denmark)

Kant, K. Mohan; Bahl, Christian Robert Haffenden; Pryds, Nini

2010-01-01

This work investigates the structural and the magnetic properties of Gd/Fe multilayered thin films grown by pulsed laser deposition onto Si (001) substrates at room temperature. he Fe layer thickness is varied from 70 to 150 nm and its effect on the structural and magnetic properties of Fe/Gd/Fe ...

The influence of Cd-dopant on the properties of α-FeOOH and α-Fe2O3 particles precipitated in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2007-01-01

The effects of Cd-dopant on the phenomenology of the precipitation of α-(Fe, Cd)OOH and α-(Fe, Cd) 2 O 3 particles, the formation of solid solutions, particle size and their geometrical shapes were investigated using Moessbauer and Fourier transform infrared (FT-IR) spectroscopies, field emission scanning electron microscopy (FE SEM) and energy dispersive X-ray analysis (EDS). The formation of merely α-(Fe, Cd)OOH solid solutions was measured up to r = 0.0196, where r = [Cd]/([Cd] + [Fe]). The formation of two types of solid solutions, α-(Fe, Cd)OOH and α-(Fe, Cd) 2 O 3 was found at r between 0.0291 and 0.0698, whereas the formation of an α-(Fe, Cd) 2 O 3 solid solution alone was obtained at r = 0.0909. The incorporation of Cd-substitutions into α-FeOOH and α-Fe 2 O 3 structures decreased the hf > values of the corresponding hyperfine magnetic field. The IR band at 639 cm -1 , recorded for α-FeOOH, was found to be sensitive to Cd-substitutions. With an increased r value a gradual elongation of α-(Fe, Cd)OOH particles along the c-axis was observed, with the maximum elongation (∼600-700 nm) obtained at r = 0.0476. At the same time, particle width (b-axis direction) and thickness (a-axis direction) showed a gradual decrease. With a further increase in the r value the length of α-(Fe, Cd)OOH particles rapidly decreased. α-(Fe, Cd) 2 O 3 particles ∼100-200 nm in size were obtained at r = 0.0909

Santa Fe, NM 1:250,000 Quad West Half USGS Land Use/Land Cover, 2000

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This land cover data set was produced as part of a cooperative project between the U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (USEPA)...

Santa Fe, NM 1:250,000 Quad East Half USGS Land Use/Land Cover, 2000

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This land cover data set was produced as part of a cooperative project between the U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (USEPA)...

Size-Controlled Synthesis of Fe3O4 Magnetic Nanoparticles in the Layers of Montmorillonite

Directory of Open Access Journals (Sweden)

Katayoon Kalantari

2014-01-01

Full Text Available Iron oxide nanoparticles (Fe3O4-NPs were synthesized using chemical coprecipitation method. Fe3O4-NPs are located in interlamellar space and external surfaces of montmorillonite (MMT as a solid supported at room temperature. The size of magnetite nanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium. The interlamellar space changed from 1.24 nm to 2.85 nm and average diameter of Fe3O4 nanoparticles was from 12.88 nm to 8.24 nm. The synthesized nanoparticles were characterized using some instruments such as transmission electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and Fourier transform infrared spectroscopy.

Enhanced antiferromagnetic coupling in dual-synthetic antiferromagnet with Co2FeAl electrodes

International Nuclear Information System (INIS)

Zhang, D.L.; Xu, X.G.; Wu, Y.; Li, X.Q.; Miao, J.; Jiang, Y.

2012-01-01

We study dual-synthetic antiferromagnets (DSyAFs) using Co 2 FeAl (CFA) Heusler electrodes with a stack structure of Ta/CFA/Ru/CFA/Ru/CFA/Ta. When the thicknesses of the two Ru layers are 0.45 nm, 0.65 nm or 0.45 nm, 1.00 nm, the CFA-based DSyAF has a strong antiferromagnetic coupling between adjacent CFA layers at room temperature with a saturation magnetic field of ∼11,000 Oe, a saturation magnetization of ∼710 emu/cm 3 and a coercivity of ∼2.0 Oe. Moreover, the DSyAF has a good thermal stability up to 400 °C, at which CFA films show B2-ordered structure. Therefore, the CFA-based DSyAFs are favorable for applications in future spintronic devices. - Graphical abstract: Display Omitted Highlights: ► Co 2 FeAl can be applied in room temperature dual-synthetic antiferromagnets. ► Co 2 FeAl dual-synthetic antiferromagnets have a good thermal stability up to 400 °C. ► The Co 2 FeAl has B2-ordered structure in annealed dual-synthetic antiferromagnets.

Interlayer exchange coupling, dipolar coupling and magnetoresistance in Fe/MgO/Fe trilayers with a subnanometer MgO barrier

Energy Technology Data Exchange (ETDEWEB)

Kozioł-Rachwał, A. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Skowroński, W.; Frankowski, M. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Chęciński, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ziętek, S.; Rzeszut, P. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ślęzak, M.; Matlak, K.; Ślęzak, T. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Stobiecki, T. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Korecki, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland)

2017-02-15

Fe/MgO/Fe trilayers with a subnanometer MgO tunnel barrier were grown by molecular beam epitaxy. Longitudinal magnetooptic Kerr effect measurements confirmed the existence of the antiferromagnetic interlayer exchange coupling (IEC) between the Fe layers for 2 Ånm to 520 nm. We showed that the dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers, and we determined dependence of the dipolar coupling on the pillar diameter. Finally, magnetoresistance (MR) was measured as a function of MgO thickness (d{sub MgO}), and a non-zero MR was found for the MgO as thin as 3.4 Å. Extrapolation of the MR (d{sub MgO}) dependence to MR=0 allowed us to determine the length of the pinholes in our sample, which was estimated to be (3.2±0.5) Å. - Highlights: • Strong antiferromagnetic (AFM) interlayer exchange coupling (IEC) between Fe layers in Fe/MgO/Fe. • After nanofabrication the effective AFM IEC is enhanced due to the dipolar coupling. • The dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers. • Non-zero magnetoresistance values registered for the Fe/MgO/Fe trilayers with the MgO spacers as thin as 3.4 Å.

Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate

International Nuclear Information System (INIS)

Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

2016-01-01

Highlights: • A route to prepare nano α-Fe 2 O 3 red pigment from waste ferrous sulfate is proposed. • Acidithiobacillus ferrooxidans is introduced for accelerating iron oxidation. • The particle size of synthetic α-Fe 2 O 3 is ranged from 22 nm to 86 nm. • The prepared nano α-Fe 2 O 3 red pigment fulfills ISO 1248-2006. - Abstract: Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe 2 O 3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe 2 O 3 red pigment powders contained 98.24 wt.% of Fe 2 O 3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22 nm to 86 nm and averaged at 45 nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

Controllable synthesis and characterization of Fe3O4/Au composite nanoparticles

International Nuclear Information System (INIS)

Xing, Yan; Jin, Yan-Yan; Si, Jian-Chao; Peng, Ming-Li; Wang, Xiao-Fang; Chen, Chao; Cui, Ya-Li

2015-01-01

Fe 3 O 4 /Au composite nanoparticles (GoldMag NPs) have received considerable attention because of their advantageous properties arisen from both individual Au and Fe 3 O 4 nanoparticles. Many efforts have been devoted to the synthesis of these composite nanoparticles. Herein, GoldMag NPs were reported to be synthesized by two-step method. Fe 3 O 4 nanoparticles were prepared by co-precipitation and modified by the citric acid, and then citric acid-coated Fe 3 O 4 nanoparticles were used as seeds in sodium citrate solution to reduce the HAuCl 4 . The size of obtained nanoparticles was geared from 25 to 300 nm by controlling the concentration of reactants. The GoldMag NPs were characterized by UV–vis spectrometer, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The GoldMag NPs showed good superparamagnetism at room temperature and were well dispersed in water with surface plasmon resonance absorption peak varied from 538 nm to 570 nm. - Highlights: • A low cost, simple manipulation and nontoxic approach was designed for preparation of magnetic Fe 3 O 4 /Au (GoldMag NPs) nanocomposites. • The size of GoldMag NPs could be controlled from 25 to 300 nm by varying the concentration of reactants. • GoldMag NPs possessed good magnetic response, high dispersion, and good stability

Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

International Nuclear Information System (INIS)

Liu Wen-Feng; Zhang Min-Gang; Zhang Ke-Wei; Zhang Hai-Jie; Chai Yue-Sheng; Xu Xiao-Hong

2016-01-01

Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. (paper)

Chemical decontamination of Santa Maria de Garona NPP recirculation loops

Energy Technology Data Exchange (ETDEWEB)

Coello, R. [Santa Maria de Garona NPP - NUCLENOR, S.A. (Spain)

2002-07-01

Santa Maria de Garona is a boiling water reactor (BWR-3) with a Primary Containment type Mark 1. Its electrical power is 466 Mw and began its commercial operation in 1971. The plant currently operates in 24 month cycles. The reactor water recirculation system (RWRS) is composed of two independent loops. Each of them has a one stage vertical centrifugal recirculation pump, with a nominal flow of 2020 l/s, and ten jet pumps. It is worthy of mention that in 1986 it was started to inject hydrogen into the feedwater (concentration = 0,3 mg/l) in order to implement the chemical condition known as hydrogen water chemistry (HWC) in the primary circuit. The objective was to create an electrochemical potential below -230 mV in the RWRS which is assumed to be low enough to mitigate the intergranular stress corrosion cracking phenomena (IGSCC) in the sensitized austenitic stainless steels. Later, in 1994, the hydrogen concentration in the feedwater was increased to 0,9 mg/l in order to obtain the protection's ECP in the bottom of the reactor vessel. This feedwater hydrogen concentration has been maintained since then. The nature of the oxides that are formed in the RWRS is strongly affected by the electrochemical conditions (ECP) which have been maintained in this system. It is frequent to find oxides like Fe{sub 2}O{sub 3} (hematite), Fe{sub 3}O{sub 4} (magnetite), NiFe{sub 2}O{sub 4} (trevorite), Cr{sub 2} FeO{sub 4} (chromite), Fe{sub 3-x-y} Cr{sub x} Ni{sub y} O{sub 4} (spinels), etc. However, it is normal to find a combination of all of them in various proportions, depending on the ECP established. Radioactive isotopes of the transition metals ({sup 60}Co, {sup 54}Mn, {sup 51}Cr, {sup 59}Fe, etc.) also participate in these oxides and contribute greatly to increase the dose rate in the circuit. The chemical decontamination processes are designed for the effective dissolution of the metallic oxides present and therefore the type of process to be applied will depend

Temperature dependence of the interfacial magnetic anisotropy in W/CoFeB/MgO

Directory of Open Access Journals (Sweden)

Kyoung-Min Lee

2017-06-01

Full Text Available The interfacial perpendicular magnetic anisotropy in W/CoFeB (1.2 ∼ 3 nm/MgO thin film structures is strongly dependent on temperature, and is significantly reduced at high temperature. The interfacial magnetic anisotropy is generally proportional to the third power of magnetization, but an additional factor due to thermal expansion is required to explain the temperature dependence of the magnetic anisotropy of ultrathin CoFeB films. The reduction of the magnetic anisotropy is more prominent for the thinner films; as the temperature increases from 300 K to 400 K, the anisotropy is reduced ∼50% for the 1.2-nm-thick CoFeB, whereas the anisotropy is reduced ∼30% for the 1.7-nm-thick CoFeB. Such a substantial reduction of magnetic anisotropy at high temperature is problematic for data retention when incorporating W/CoFeB/MgO thin film structures into magneto-resistive random access memory devices. Alternative magnetic materials and structures are required to maintain large magnetic anisotropy at elevated temperatures.

33 CFR 334.730 - Waters of Santa Rosa Sound and Gulf of Mexico adjacent to Santa Rosa Island, Air Force Proving...

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Waters of Santa Rosa Sound and..., Fla. 334.730 Section 334.730 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.730 Waters of Santa Rosa...

Control of crystallite orientation and size in Fe and FeCo nanoneedles

International Nuclear Information System (INIS)

Mendoza-Reséndez, Raquel; Luna, Carlos; Diaz Barriga-Castro, Enrique; Bonville, Pierre; Serna, Carlos J

2012-01-01

Uniform magnetic nanoneedles have been prepared by hydrogen reduction of elongated nanoarchitectures. These precursors are as-prepared or cobalt-coated aggregates of highly oriented haematite nanocrystals (∼5 nm). The final materials are flattened nanoneedles formed by chains of assembled Fe or FeCo single-domain nanocrystals. The microstructural properties of such nanoneedles were tailored using renewed and improved synthetic strategies. In this fashion, the needle elongation and composition, the crystallite size (from 15 up to 30 nm), the nanocrystal orientation (with the 〈110〉 or 〈001〉 directions roughly along the long axis of the nanoneedle) and their type of arrangement (single chains, frustrated double chains and double chains) were controlled by modifying the reduction time, the axial ratio of the precursor haematite and the presence of additional coatings of aluminum or yttrium compounds. The values of the coercivity H C found for these nanoneedles are compared with the values predicted by the chain of spheres model assuming a symmetric fanning mechanism for magnetization reversal. (paper)

Synthesis of peptide templated copper nanoclusters for fluorometric determination of Fe(III) in human serum

International Nuclear Information System (INIS)

Tang, Ting; Ouyang, Jiang; Hu, Lanshuang; Guo, Linyan; Yang, Minghui; Chen, Xiang

2016-01-01

Copper nanoclusters (Cu-NCs) were prepared by reducing CuCl 2 with ascorbic acid in the presence of the short peptide template Cys-Cys-Cys-Asp-Leu. They were characterized by UV-vis absorption and fluorescence spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. The Cu-NCs have a size of ∼2 nm, can be well dispersed in water and are photostable. Their fluorescence (peaking at 425 nm under 365-nm excitation) is quenched by Fe(III) ions. Based on this finding, a sensitive and selective fluorescence assay for the detection of Fe(III) was developed. Under optimized conditions and a pH value of 2.0, the assay displays a linear response in the 0.05 to 30 μM Fe(III) concentration range, with a detection limit of 20 nM based on an S/N ratio of 3. The assay was successfully applied to the determination of Fe(III) in spiked human serum where is gave recoveries that ranged from 96.2 % to 98.3 %. (author)

Magnetic interaction reversal in watermelon nanostructured Cr-doped Fe nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Kaur, Maninder; Qiang, You, E-mail: youqiang@uidaho.edu [Department of Physics, University of Idaho, Moscow, Idaho 83844 (United States); Dai, Qilin; Tang, Jinke [Department of Physics and Astronomy, University of Wyoming, Laramie, Wyoming 82071 (United States); Bowden, Mark; Engelhard, Mark [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Wu, Yaqiao [Department of Materials Science and Engineering, Boise State University, Boise, Idaho 83725 (United States); Center for Advanced Energy Studies, Idaho Falls, Idaho 83401 (United States)

2013-11-11

Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (<10 at. %) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr{sub 2}O{sub 3} and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (∼25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of σ-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs.

Synthesis of Fe nanoparticles-graphene composites for environmental applications

International Nuclear Information System (INIS)

Guo, Juan; Wang, Ruiyu; Tjiu, Weng Weei; Pan, Jisheng; Liu, Tianxi

2012-01-01

Graphical abstract: Fe nanoparticles-graphene composites (FGC) are successfully synthesized by forming a complex Fe 3+ -GO and further reducing it with NaBH4 as one step at ambient condition. The morphology and structure studies of FGC indicate that Fe nanoparticles with size of about 5 nm are finely dispersed on graphene sheets. Decolorization experiments show that the FGC hybrids display better removal capacities to decolorize methyl blue (MB), a model dye in the dyeing and printing industry, compared with bare Fe particles. On the other hand, FGC hybrids exhibit superparamagnetic properties and can be separated from MB solution leaving a colorless solution by using a magnet. All of these suggest FGC an excellent candidate for dye removal. Highlights: ► Graphene oxide (GO) and Fe 3+ are used as precursors. ► By adding NaBH 4 , Fe 3+ and GO are in situ reduced to Fe and graphene, respectively, thus forming FGC hybrids. ► Fe nanoparticles with size of about 5 nm are finely dispersed on graphene sheets. ► FGC hybrids have better decolorization capacities than bare Fe nanoparticles. - Abstract: Fe nanoparticles-graphene composites (FGC) are successfully synthesized by using graphene oxide (GO) as a supporting matrix. GO is first treated with Fe 3+ to form Fe 3+ -GO complexes. Then, by adding NaBH 4 solution, Fe 3+ and GO are simultaneously reduced in situ to Fe and graphene respectively, forming FGC hybrid composites. The structures, properties and applications of the hybrids thus obtained are investigated by X-ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis and magnetization measurements. The hybrids are also evaluated for decolorization of methyl blue solution, a model dye in wastewater of dyeing industry. Compared with bare Fe particles, the high removal capacities of FGC are due to the

Study of ion beam sputtered Fe/Si interfaces as a function of Si layer thickness

Science.gov (United States)

Kumar, Anil; Brajpuriya, Ranjeet; Singh, Priti

2018-01-01

The exchange interaction in metal/semiconductor interfaces is far from being completely understood. Therefore, in this paper, we have investigated the nature of silicon on the Fe interface in the ion beam deposited Fe/Si/Fe trilayers keeping the thickness of the Fe layers fixed at 3 nm and varying the thickness of the silicon sandwich layer from 1.5 nm to 4 nm. Grazing incidence x-ray diffraction and atomic force microscopy techniques were used, respectively, to study the structural and morphological changes in the deposited films as a function of layer thickness. The structural studies show silicide formation at the interfaces during deposition and better crystalline structure of Fe layers at a lower spacer layer thickness. The magnetization behavior was investigated using magneto-optical Kerr effect, which clearly shows that coupling between the ferromagnetic layers is highly influenced by the semiconductor spacer layer thickness. A strong antiferromagnetic coupling was observed for a value of tSi = 2.5 nm but above this value an unexpected behavior of hysteresis loop (step like) with two coercivity values is recorded. For spacer layer thickness greater than 2.5 nm, an elemental amorphous Si layer starts to appear in the spacer layer in addition to the silicide layer at the interfaces. It is observed that in the trilayer structure, Fe layers consist of various stacks, viz., Si doped Fe layers, ferromagnetic silicide layer, and nonmagnetic silicide layer at the interfaces. The two phase hysteresis loop is explained on the basis of magnetization reversal of two ferromagnetic layers, independent of each other, with different coercivities. X-ray photo electron spectroscopy technique was also used to study interfaces characteristics as a function of tSi.

1D Atmosphere Models from Inversion of Fe i 630 nm Observations with an Application to Solar Irradiance Studies

Energy Technology Data Exchange (ETDEWEB)

Cristaldi, Alice; Ermolli, Ilaria, E-mail: alice.cristaldi@oaroma.inaf.it [INAF Osservatorio Astronomico di Roma, via Frascati 33, Monte Porzio Catone, I-00078 (Italy)

2017-06-01

Present-day semi-empirical models of solar irradiance (SI) variations reconstruct SI changes measured on timescales greater than a day by using spectra computed in one dimensional atmosphere models (1D models), which are representative of various solar surface features. Various recent studies have pointed out, however, that the spectra synthesized in 1D models do not reflect the radiative emission of the inhomogenous atmosphere revealed by high-resolution solar observations. We aimed to derive observation-based atmospheres from such observations and test their accuracy for SI estimates. We analyzed spectropolarimetric data of the Fe i 630 nm line pair in photospheric regions that are representative of the granular quiet-Sun pattern (QS) and of small- and large-scale magnetic features, both bright and dark with respect to the QS. The data were taken on 2011 August 6, with the CRisp Imaging Spectropolarimeter at the Swedish Solar Telescope, under excellent seeing conditions. We derived atmosphere models of the observed regions from data inversion with the SIR code. We studied the sensitivity of results to spatial resolution and temporal evolution, and discuss the obtained atmospheres with respect to several 1D models. The atmospheres derived from our study agree well with most of the 1D models we compare our results with, both qualitatively and quantitatively (within 10%), except for pore regions. Spectral synthesis computations of the atmosphere obtained from the QS observations return an SI between 400 and 2400 nm that agrees, on average, within 2.2% with standard reference measurements, and within −0.14% with the SI computed on the QS atmosphere employed by the most advanced semi-empirical model of SI variations.

CoFe Layers Thickness and Annealing Effect on the Magnetic Behavior of the CoFe/Cu Multilayer Nanowires

Directory of Open Access Journals (Sweden)

M. Ahmadzadeh

2015-04-01

Full Text Available CoFe/Cu multilayer nanowires were electrodeposited into anodic aluminum oxide templates prepared by a two-step mild anodization method, using the single-bath technique. Nanowires with 30 nm diameter and the definite lengths were obtained. The effect of CoFe layers thickness and annealing on the magnetic behavior of the multilayer nanowires was investigated. The layers thickness was controlled through the pulses numbers: 200, 260, 310,360 and 410 pulses were used to deposit the CoFe layers, while 300 pulse for the Cu layers. A certain increase in coercivity and squareness of CoFe/Cu multilayer nanowires observed with increasing the CoFe layer thickness and annealing improved the coercivity and decrease squareness of CoFe/Cu multilayer nanowires. First order reversal curves after annealed showed amount domains with soft magnetic phase, it also shows decreasing spreading of distribution function along the Hu axis after annealed

High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

Directory of Open Access Journals (Sweden)

Anabil Gayen

2013-01-01

Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

Energy Technology Data Exchange (ETDEWEB)

Kalisvaart, W.P., E-mail: pkalisvaart@gmail.com [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada); Mitlin, David, E-mail: dmitlin@ualberta.ca [Chemical and Materials Engineering, University of Alberta and National Research Council Canada, National Institute for Nanotechnology, Edmonton, AB, T6G 2V4 (Canada)

2011-03-15

This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

Microstructural evolution during hydrogen sorption cycling of Mg-FeTi nanolayered composites

International Nuclear Information System (INIS)

Kalisvaart, W.P.; Kubis, Alan; Danaie, Mohsen; Amirkhiz, Babak Shalchi; Mitlin, David

2011-01-01

This paper describes the microstructural evolution of Mg-FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg-5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg-10%Fe-10%Ti), which is included as a baseline case. At 200 deg. C, the FeTi layers act as a barrier, preventing agglomeration of Mg particles. At 300 deg. C, the initial structure of the multilayer is preserved up to 35 cycles, followed by fracturing of the Mg layers in the in-plane direction and progressive delamination of the FeTi layers as observed by electron microscopy. Concurrently, an increase in the Mg grain size was observed from 32 to 76 nm between cycles 35 and 300. As a result, the absorption kinetics deteriorate with cycling, although 90% of the total capacity is still absorbed within 2 min after as many as 300 cycles. The desorption kinetics, on the other hand, remain rapid and stable, and complete desorption of 4.6 wt.% H is achieved in 1.5 min at ambient desorption pressure. In addition to showing good hydrogen storage performance, multilayers are an excellent model system for studying the relation between microstructure and hydrogen absorption/desorption kinetics.

Study of the Thermodynamics of Chromium(III) and Chromium(VI) Binding to Fe3O4 and MnFe2O4 nanoparticles

Science.gov (United States)

Luther, Steven; Brogfeld, Nathan; Kim, Jisoo; Parsons, J.G.

2013-01-01

Removal of chromium(III) or (VI) from aqueous solution was achieved using Fe3O4, and MnFe2O4 nanomaterials. The nanomaterials were synthesized using a precipitation method and characterized using XRD. The size of the nanomaterials was determined to be 22.4 ± 0.9 nm (Fe3O4) and 15.5 ± 0.5 nm (MnFe2O4). The optimal binding pH for chromium(III) and chromium(VI) were pH 6 and pH 3. Isotherm studies were performed, under light and dark conditions, to determine the capacity of the nanomaterials. The capacities for the light studies with MnFe2O4 and Fe3O4 were determined to be 7.189 and 10.63 mg/g, respectively, for chromium(III). The capacities for the light studies with MnFe2O4 and Fe3O4 were 3.21 and 3.46 mg/g, respectively, for chromium(VI). Under dark reaction conditions the binding of chromium(III) to the MnFe2O4 and Fe3O4 nanomaterials were 5.74 and 15.9 mg/g, respectively. The binding capacity for the binding of chromium(VI) to MnFe2O4 and Fe3O4 under dark reaction conditions were 3.87 and 8.54 mg/g, respectively. The thermodynamics for the reactions showed negative ΔG values, and positive ΔH values. The ΔS values were positive for the binding of chromium(III) and for chromium(VI) binding under dark reaction conditions. The ΔS values for chromium(VI) binding under the light reaction conditions were determined to be negative. PMID:23558081

Influence of Zn/Fe Molar Ratio on Optical and Magnetic Properties of ZnO and ZnFe2O4 Nanocrystal as Calcined Products of Layered Double Hydroxides

Directory of Open Access Journals (Sweden)

Abdullah Ahmed Ali Ahmed

2014-01-01

Full Text Available The coprecipitation method has been used to synthesize layered double hydroxide (Zn-Fe-LDH nanostructure at different Zn2+/Fe3+ molar ratios. The structural properties of samples were studied using powder X-ray diffraction (PXRD. LDH samples were calcined at 600°C to produce mixed oxides (ZnO and ZnFe2O4. The crystallite size of mixed oxide was found in the nanometer scale (18.1 nm for ZnFe2O4 and 43.3 nm for ZnO. The photocatalytic activity of the calcination products was investigated using ultraviolet-visible-near infrared (UV-VIS-NIR diffuse reflectance spectroscopy. The magnetic properties of calcined LDHs were investigated using a vibrating sample magnetometer (VSM. The calcined samples showed a paramagnetic behavior for all Zn2+/Fe3+ molar ratios. The effect of molar ratio on magnetic susceptibility of the calcined samples was also studied.

Characterisation of Fe-bearing particles and colloids in the Lena River basin, NE Russia

Science.gov (United States)

Hirst, Catherine; Andersson, Per S.; Shaw, Samuel; Burke, Ian T.; Kutscher, Liselott; Murphy, Melissa J.; Maximov, Trofim; Pokrovsky, Oleg S.; Mörth, Carl-Magnus; Porcelli, Don

2017-09-01

Rivers are significant contributors of Fe to the ocean. However, the characteristics of chemically reactive Fe remain poorly constrained, especially in large Arctic rivers, which drain landscapes highly susceptible to climate change and carbon cycle alteration. The aim of this study was a detailed characterisation (size, mineralogy, and speciation) of riverine Fe-bearing particles (>0.22 μm) and colloids (1 kDa-0.22 μm) and their association with organic carbon (OC), in the Lena River and tributaries, which drain a catchment almost entirely underlain by permafrost. Samples from the main channel and tributaries representing watersheds that span a wide range in topography and lithology were taken after the spring flood in June 2013 and summer baseflow in July 2012. Fe-bearing particles were identified, using Transmission Electron Microscopy, as large (200 nm-1 μm) aggregates of smaller (20-30 nm) spherical colloids of chemically-reactive ferrihydrite. In contrast, there were also large (500 nm-1 μm) aggregates of clay (illite) particles and smaller (100-200 nm) iron oxide particles (dominantly hematite) that contain poorly reactive Fe. TEM imaging and Scanning Transmission X-ray microscopy (STXM) indicated that the ferrihydrite is present as discrete particles within networks of amorphous particulate organic carbon (POC) and attached to the surface of primary produced organic matter and clay particles. Together, these larger particles act as the main carriers of nanoscale ferrihydrite in the Lena River basin. The chemically reactive ferrihydrite accounts for on average 70 ± 15% of the total suspended Fe in the Lena River and tributaries. These observations place important constraints on Fe and OC cycling in the Lena River catchment area and Fe-bearing particle transport to the Arctic Ocean.

Santa Elena. Ready to reshape its transport energy matrix

Energy Technology Data Exchange (ETDEWEB)

Moreano, Hernan [Universidad Estatal Peninsula de Santa Elena (Ecuador). Inst. de Investigacion Cientifica y Desarrollo Tecnologico (INCYT)

2012-07-01

The renewable energy issue opens the door to an ambient of opportunities. Santa Elena, one of the coastal provinces of Ecuador has the chance to go from a fossil fuel energy culture to a new energy scheme based on the use of environmental friendly fuels like natural gas and other renewable energy carriers like hydrogen. The marginal production of oil and natural gas from the Gustavo Galindo Velasco field and the updated gas reserves from the Gulf of Guayaquil make it possible. Infrastructure for natural gas production and distribution for vehicles is almost ready and any of the three refineries can generate hydrogen from natural gas. This provides the opportunity to reshape the Santa Elena transport energy matrix, where vehicles can burn natural gas and inter country buses can work with hydrogen. Traditional Fishing boats can be fitted with hydrogen storage and fuel systems later on. Santa Elena should face this challenge through a joint effort of public and private parties. Santa Elena State University and its partners as a focus point to create: The Campus of Energy Knowledge, where research, science and technology will serve companies that work in the energy business with a strong synergy, which will create jobs for the Santa Elena people. (orig.)

The dependence of critical current density of GdFeCo layer on composition of thermally assisted STT-RAM

Science.gov (United States)

Dai, B.; Zhu, J.; Liu, K.; Yang, L.; Han, J.

2017-07-01

Amorphous rare earth-transitional metal (RETM) GdFeCo memory layer with RE- and TM-rich compositions was fabricated in stacks of GdFeCo (10 nm)/Cu (3 nm)/[Co(0.2 nm)/Pd(0.4 nm)]6. Their magnetic properties and spin transfer torque (STT) switching of magnetization were investigated. The maximum magneto-resistance (MR) was around 0.24% for the TM-rich Gd21.4 (Fe90Co10)78.6 memory layer and was -0.03% for the RE-rich Gd29.0 (Fe90Co10)71.0 memory layer. The critical current densities Jc to switch the GdFeCo memory layers are in the range of 1.4 × 107 A/cm2-4.5 × 107 A/cm2. The dependence of critical current density Jc and effective anisotropy constant Keff on Gd composition were also investigated. Both Jc and Keff have maximum values in the Gd composition range from 21-29 at.%, suitable for thermally assisted STT-RAM for storage density exceeding Gb/inch2.

Santa soja: narrativa documental em fotolivro

OpenAIRE

Seidl, Eduardo

2016-01-01

A partir do fotolivro Santa Soja como objeto e do resgate histórico das práticas jornalísticas de reportagem e de edição por meio de entrevistas com os cinco autores, esta pesquisa busca identificar o fotolivro como formato potencializador do fotodocumentarismo. Para tanto, foi proposta uma localização conceitual sobre o fotolivro, a linguagem e a narrativa fotográfica e sobre a vocação historiográfica e testemunhal da fotografia, a fim de contextualizar uma análise do fotolivro Santa Soja qu...

Santa Cruz thermic plant islanding with local loads

Energy Technology Data Exchange (ETDEWEB)

Nascimento, A R [Light Servicos de Eletricidade SA, Rio de Janeiro, RJ (Brazil); Gomes, Paulo; Almeida, Paulo C. de [ELETROBRAS, Rio de Janeiro, RJ (Brazil); Sereno, Marcos G [FURNAS, Rio de Janeiro, RJ (Brazil)

1988-12-31

This work looks into the feasibility of implementing a scheme for the islanding of the Santa Cruz Thermic Plant ( Rio de janeiro State) with LIGHT`s (Electric power public utility) loads fed by the Santa Cruz-Jacarepagua trunk connection, considering presently-existing system problems relative to a significant frequency drop when a loss occurs of a large generation block and which causes the blockade scheme of the mentioned Plant to work, thus aggravating the frequency control still further. An analysis is made of such scheme implementation implications on the scheme for islanding a Santa Cruz 84 MW machine to provide supply to the auxiliary services of The Angra dos Reis nuclear plant presently existing in the system. 2 refs., 9 figs.

Buffer layer dependence of magnetoresistance effects in Co2Fe0.4Mn0.6Si/MgO/Co50Fe50 tunnel junctions

Science.gov (United States)

Sun, Mingling; Kubota, Takahide; Takahashi, Shigeki; Kawato, Yoshiaki; Sonobe, Yoshiaki; Takanashi, Koki

2018-05-01

Buffer layer dependence of tunnel magnetoresistance (TMR) effects was investigated in Co2Fe0.4Mn0.6Si (CFMS)/MgO/Co50Fe50 magnetic tunnel junctions (MTJs). Pd, Ru and Cr were selected for the buffer layer materials, and MTJs with three different CFMS thicknesses (30, 5, and 0.8 nm) were fabricated. A maximum TMR ratio of 136% was observed in the Ru buffer layer sample with a 30-nm-thick CFMS layer. TMR ratios drastically degraded for the CFMS thickness of 0.8 nm, and the values were 26% for Cr buffer layer and less than 1% for Pd and Ru buffer layers. From the annealing temperature dependence of the TMR ratios, amounts of interdiffusion and effects from the lattice mismatch were discussed.

Anodic oxidation of Ta/Fe alloys

International Nuclear Information System (INIS)

Mato, S.; Alcala, G.; Thompson, G.E.; Skeldon, P.; Shimizu, K.; Habazaki, H.; Quance, T.; Graham, M.J.; Masheder, D.

2003-01-01

The behaviour of iron during anodizing of sputter-deposited Ta/Fe alloys in ammonium pentaborate electrolyte has been examined by transmission electron microscopy, Rutherford backscattering spectroscopy, glow discharge optical emission spectroscopy and X-ray photoelectron spectroscopy. Anodic films on Ta/1.5 at.% Fe, Ta/3 at.% Fe and Ta/7 at.% Fe alloys are amorphous and featureless and develop at high current efficiency with respective formation ratios of 1.67, 1.60 and 1.55 nm V -1 . Anodic oxidation of the alloys proceeds without significant enrichment of iron in the alloy in the vicinity of the alloy/film interface and without oxygen generation during film growth, unlike the behaviour of Al/Fe alloys containing similar concentrations of iron. The higher migration rate of iron species relative to that of tantalum ions leads to the formation of an outer iron-rich layer at the film surface

One-pot synthesis of FePt/CNTs nanocomposites for efficient cellular imaging and cancer therapy

Energy Technology Data Exchange (ETDEWEB)

Chen, Weihong; Zheng, Xiuwen, E-mail: xwzheng1976@163.com [Linyi University, School of Chemistry & Chemical Engineering, Shandong Provincial Key Laboratory of Detection Technology for Tumor Makers (China); Li, Shulian [Linyi Tumor Hospital (China); Zhang, Wei; Wen, Xin [Linyi University, School of Chemistry & Chemical Engineering, Shandong Provincial Key Laboratory of Detection Technology for Tumor Makers (China); Yue, Ludan [Shandong Normal University (China); Wang, Jinlong [Shandong University of Technology (China)

2015-11-15

Here, we developed a facile route to synthesize carbon nanotube-based FePt nanocomposites (FePt/CNTs) as a potential theranostic platform in the cancer treatment. FePt/CNTs were firstly synthesized via one-pot polyol route, and then functionalized with 6-arm-polyethylene glycol-amine polymer. The average size of FePt nanoparticles (NPs) is 3–4 nm, which is dispersed on the CNT surface (ca.50–150 nm). The as-prepared FePt NPs display high cytotoxicity by highly reactive oxygen species in cancer cells. Folic acid and fluorescein isothiocyanate are assembled onto the surface of FePt/CNTs for effective targeting of folate receptor-positive cancer cells and simultaneously for the visualization of cellular uptake. Therefore, the FePt/CNTs NPs capability of simultaneously performing diagnosis, therapy, and targeting is, therefore, promising for future potential widespread application in biomedicine.

Synthesis and characterization of iron-cobalt (FeCo) alloy nanoparticles supported on carbon

DEFF Research Database (Denmark)

Koutsopoulos, Sotiris; Barfod, Rasmus; Eriksen, Kim Michael

2017-01-01

of the alloy nanoparticles differed depending on the preparation method. When the wet impregnation technique of acetate precursor salts of Fe and Co were used for the synthesis, the size of FeCo alloy nanoparticles was approximately 13 nm. FeCo alloy nanoparticles were characterized by crystallography (XRD...

Synthesis and influence of alkaline concentration on α-FeOOH ...

Indian Academy of Sciences (India)

-FeOOH nanorods having uniform morphology were synthesized by water bath process. X-ray diffraction and transmission electron microscopy revealed that the single-crystalline orthorhombic -FeOOH nanorods are about 10 nm in diameter and hundreds of nanometer in length. The effect of concentration of KOH on ...

Decolorization of Methylene Blue by Persulfate Activated with FeO Magnetic Particles.

Science.gov (United States)

Hung, Chang-Mao; Chen, Chiu-Wen; Liu, Yi-Yuan; Dong, Cheng-Di

2016-08-01

In this study, the degradation of methylene blue (MB) was conducted to evaluate the feasibility of using persulfate oxidation activated with iron oxide (FeO) magnetic particles. The results demonstrated that the decolorization rate of MB increased with increasing FeO concentration, exhibiting maximum efficiency at pH0 3.0. The kinetics of MB was studied in the binary FeO catalyst and persulfate oxidation system. The surface properties of FeO before and after reaction was analyzed using cyclic voltammogram (CV), three-dimensional excitation-emission fluorescence matrix (EEFM) spectroscopy, zeta potential, particle size distribution measurements, X-ray diffraction (XRD) and environmental scanning electron microscopy-energy dispersive X-ray spectrometry (ESEM-EDS). The CV data indicated that a reversible redox reaction holds the key to explaining the significant activity of the catalyst. EEFM was used to evaluate the catalyst yield of FeO by fluorescence intensity plots with excitation/emission at 220/300 nm and 260/300 nm. The XRD and ESEM-EDS results confirmed the presence of FeO in the catalyst.

Hard magnetic properties of rapidly annealed NdFeB thin films on Nb and V buffer layers

International Nuclear Information System (INIS)

Jiang, H.; Evans, J.; O'Shea, M.J.; Du Jianhua

2001-01-01

NdFeB thin films of the form A (20 nm)/NdFeB(d nm)/A(20 nm), where d ranges from 54 to 540 nm and the buffer layer A is Nb or V were prepared on a Si(1 0 0) substrate by magnetron sputtering. The hard Nd 2 Fe 14 B phase is formed by a 30 s rapid anneal or a 20 min anneal. Average crystallite size ranged from 20 to 35 nm with the rapidly annealed samples having the smaller crystallite size. These samples also exhibited a larger coercivity and energy product than those treated by a 20 min vacuum anneal. A maximum coercivity of 26.3 kOe at room temperature was obtained for a Nb/NdFeB (180 nm)/Nb film after a rapid anneal at 725 deg. C. Initial magnetization curves indicate magnetization rotation rather than nucleation of reverse domains is important in the magnetization process. A Brown's equation analysis of the coercivity as a function of temperature allowed us to compare the rapidly annealed and 20 min annealed samples. This analysis suggests that rapid annealing gives higher quality crystalline grains than the 20 min annealed sample leading to the observed large coercivity in the rapidly annealed samples

Curie temperature rising by fluorination for Sm2Fe17

Directory of Open Access Journals (Sweden)

Matahiro Komuro

2013-02-01

Full Text Available Fluorine atoms can be introduced to Sm2Fe17 using XeF2 below 423 K. The resulting fluorinated Sm2Fe17 powders have ferromagnetic phases containing Sm2Fe17FY1(0Fe17FY2 (1Fe17, and α-Fe. The unit cell for Sm2Fe17 is elongated by the fluorination. The largest unit cell volume among the rhombohedral Sm2Fe17 compounds is 83.8 nm3, which is 5.8% larger than Sm2Fe17. The rhombohedral Sm2Fe17 with the largest unit cell volume is dissociated above 873 K, and fluorination increases Curie temperature from 403 K for Sm2Fe17 to 675 K. This increase can be explained by the magneto-volume effect.

"Santa Maria" forever : Eesti ja Portugali kirjandussuhetest / Toomas Haug

Index Scriptorium Estoniae

Haug, Toomas, 1956-

2012-01-01

Jaanuaris 1961 Portugali diktaatorlikule režiimile protestiks kaaperdatud laevast "Santa Maria", mis sai omamoodi vabaduse ja vastuhaku sümboliks ka okupeeritud Eestis. Artiklis käsitletakse sellest sündmusest mõjutatud teoseid, täpsemalt Aleksander Suumanni maali "Santa Maria" ja Paul-Eerik Rummo samanimelist luuletust

"Santa Maria" forever : Eesti ja Portugali kirjandussuhetest / Toomas Haug

Index Scriptorium Estoniae

Haug, Toomas, 1956-

2015-01-01

Jaanuaris 1961 Portugali diktaatorlikule režiimile protestiks kaaperdatud laevast "Santa Maria", mis sai omamoodi vabaduse ja vastuhaku sümboliks ka okupeeritud Eestis. Artiklis käsitletakse sellest sündmusest mõjutatud teoseid, täpsemalt Aleksander Suumanni maali "Santa Maria" ja Paul-Eerik Rummo samanimelist luuletust

Crystal structure of a Ce2Fe2Mg15 compound

International Nuclear Information System (INIS)

Opainich, I.M.; Pavlyuk, V.V.; Bodak, O.I.

1996-01-01

A structure of a new Ce2Fe2Mg15 ternary compound (P63/mmc sp.gr., a=1.0324(5) nm, c=1.02080(4) nm) was determined by powder methods on a DRON-4.07 automatic diffractometer. The structure of a Ce2Fe2Mg15 crystal is a new variant of the ordered Th2Ni17 type superstructure, in which cerium atoms occupy the thorium positions; magnesium atoms occupy the nickel position 6g, 12k, and 12j; and iron atoms occupy the 4f position

Magnetic properties and microstructure of low ordering temperature L10 FePt thin films

International Nuclear Information System (INIS)

Sun, A.C.; Kuo, P.C.; Chen, S.C.; Chou, C.Y.; Huang, H.L.; Hsu, J.H.

2004-01-01

Polycrystalline Fe 52 Pt 48 alloy thin films were prepared by dc magnetron sputtering on preheated natural-oxidized silicon wafer substrates. The film thickness was varied from 10 to 100 nm. The as-deposited film was encapsulated in a quartz tube and postannealed in vacuum at various temperatures for 1 h, then furnace cooled. It is found that the ordering temperature from as-deposited soft magnetic fcc FePt phase to hard magnetic fct L1 0 FePt phase could be reduced to about 350 deg. C by preheating substrate and furnace cooling treatment. The magnetic properties measurements indicated that the in-plane coercivity of the films was increased rapidly as annealing temperature is increased from 300 to 400 deg. C, but it decreased when the annealing temperature is higher than 400 deg. C. X-ray diffraction analysis shown that the as-deposited FePt thin film was a disorder fcc FePt phase. The magnetic measurement indicated that the transformation of disorder fcc FePt to fct L1 0 FePt phase was started at about 350 deg. C, which is consistent with the analysis of x-ray diffraction patterns. From scanning electron microscopy observation and selected area energy disperse spectrum analysis, the distributions of Fe and Pt elements in the films became nonuniform when the annealing temperature was higher than 500 deg. C due to the formation of the Fe 3 Pt phase. After annealing at 400 deg. C, the in plane coercivity of Fe 52 Pt 48 thin film with film thickness of 100 nm is 10 kOe, M s is 580 emu/cm3, and grain size is about 12 nm

A rhodamine–dansyl conjugate as a FRET based sensor for Fe{sup 3+} in the red spectral region

Energy Technology Data Exchange (ETDEWEB)

Xie, Puhui, E-mail: pxie2007@yahoo.com.cn [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Guo, Fengqi, E-mail: fqguo@zzu.edu.cn [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Xia, Ruirui; Wang, Yao [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China); Yao, Denghui [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Yang, Guoyu; Xie, Lixia [College of Sciences, Henan Agricultural University, Zhengzhou 450002 (China)

2014-01-15

A new fluorescent resonance energy transfer (FRET) based fluorescent probe (compound 1) containing a dansyl unit as a donor and rhodamine 101 as an acceptor was developed to detect Fe{sup 3+} from other transition metal ions through ratiometric sensing in organic-aqueous solutions. Fe{sup 3+} induced a ring-opening reaction of the spirolactam rhodamine moiety of 1 resulting in the formation of a fluorescent derivative that can serve as the FRET acceptor. Ratiometric sensing of Fe{sup 3+} was accomplished by plotting the fluorescence intensity ratio at 605 nm and 515 nm versus ferric ion concentration. The probe displayed a linear response to Fe{sup 3+} in the range of 5.5–25 μM with a detection limit of 0.64 μM. A 1:1 stoichiometry for the 1–Fe{sup 3+} complex was formed with an association constant of 1.74×10{sup 4} M{sup −1}. The probe also exhibited a large Stokes shift (225 nm) which can eliminate backscattering effects of excitation light. -- Highlights: • A new colorimetric and fluorescent “off–on” chemosensor for Fe{sup 3+} was synthesized. • It can respond to Fe{sup 3+} in the red spectral region based on a FRET mechanism. • Its ratiometric sensing for Fe{sup 3+} can be accomplished with a signal to noise ratio of 214. • The large Stokes shift (225 nm) can rule out the excitation backscattering effects.

Characterization of Bi and Fe co-doped PZT capacitors for FeRAM.

Science.gov (United States)

Cross, Jeffrey S; Kim, Seung-Hyun; Wada, Satoshi; Chatterjee, Abhijit

2010-08-01

Ferroelectric random access memory (FeRAM) has been in mass production for over 15 years. Higher polarization ferroelectric materials are needed for future devices which can operate above about 100 °C. With this goal in mind, co-doping of thin Pb(Zr 40 ,Ti 60 )O 3 (PZT) films with 1 at.% Bi and 1 at.% Fe was examined in order to enhance the ferroelectric properties as well as characterize the doped material. The XRD patterns of PZT-5% BiFeO 3 (BF) and PZT 140-nm thick films showed (111) orientation on (111) platinized Si wafers and a 30 °C increase in the tetragonal to cubic phase transition temperature, often called the Curie temperature, from 350 to 380 °C with co-doping, indicating that Bi and Fe are substituting into the PZT lattice. Raman spectra revealed decreased band intensity with Bi and Fe co-doping of PZT compared to PZT. Polarization hysteresis loops show similar values of remanent polarization, but square-shaped voltage pulse-measured net polarization values of PZT-BF were higher and showed higher endurance to repeated cycling up to 10 10 cycles. It is proposed that Bi and Fe are both in the +3 oxidation state and substituting into the perovskite A and B sites, respectively. Substitution of Bi and Fe into the PZT lattice likely creates defect dipoles, which increase the net polarization when measured by the short voltage pulse positive-up-negative-down (PUND) method.

Santa Gertrudis : Pétroglifo

OpenAIRE

Puaux , Olivier

1986-01-01

Las Milpillas ( site n°95 ), Santa Gertrudis, Municipio de Zacapu, Michoacán. Opéración 1. Groupo B. Estructura B1. Unidad Excavación Noroeste. Pétroglifo dibajo de los escombros, Fachaba Escalinatas. Coordenadas : 19°51'48" 101°49'.

Surface structure of MgO underlayer with Ti diffusion for (002 oriented L10 FePt-based heat assisted magnetic recording media

Directory of Open Access Journals (Sweden)

Sintaro Hinata

2018-05-01

Full Text Available Surface morphology of the MgO layer and magnetic properties of FePt-C layer deposited on the MgO were investigated for the FePt-based heat assisted magnetic recording media. Stacking structure of the underlayer for the FePt-C layer was MgO (0-5 nm/Cr80Mn20 (0-30 nm/Cr50Ti50 (0-50 nm/glass sub.. Surface observation result for the MgO film by using an atomic force microscope revealed the existence of nodules with a height of about 2 nm and a network-like convex structure with a height difference of about sub nm (boundary wall, BW on the MgO crystal grain boundary. Density of the nodules largely depends on the surface roughness of the CrTi layer, RaCrTi and it is suppressed from 10 to 2/0.5 μm2 by reducing RaCrTi from 420 to 260 pm. Height of the BW depends on thickness of the MgO layer, tMgO and it can be suppressed by reducing tMgO to less than 4 nm. From the cross-sectional energy dispersive x-ray mapping, it is clarified that the BW is formed by atomic diffusion of Ti atoms from CrTi layer due to the substrate heating process, and a compound consists of Mg, Ti and O atoms. This BW can be used as a template to magnetically isolate the FePt column in the FePt-based granular film, such as FePt-SiO2, if the size of the BW is reduced to less than 10 nm. M-H loop of the FePt-C granular film deposited on the underlayer showed that the nodule and BW induce oxidation of the FePt grains, and reduction of intergranular exchange coupling.

Surface structure of MgO underlayer with Ti diffusion for (002) oriented L10 FePt-based heat assisted magnetic recording media

Science.gov (United States)

Hinata, Sintaro; Jo, Shin; Saito, Shin

2018-05-01

Surface morphology of the MgO layer and magnetic properties of FePt-C layer deposited on the MgO were investigated for the FePt-based heat assisted magnetic recording media. Stacking structure of the underlayer for the FePt-C layer was MgO (0-5 nm)/Cr80Mn20 (0-30 nm)/Cr50Ti50 (0-50 nm)/glass sub.. Surface observation result for the MgO film by using an atomic force microscope revealed the existence of nodules with a height of about 2 nm and a network-like convex structure with a height difference of about sub nm (boundary wall, BW) on the MgO crystal grain boundary. Density of the nodules largely depends on the surface roughness of the CrTi layer, RaCrTi and it is suppressed from 10 to 2/0.5 μm2 by reducing RaCrTi from 420 to 260 pm. Height of the BW depends on thickness of the MgO layer, tMgO and it can be suppressed by reducing tMgO to less than 4 nm. From the cross-sectional energy dispersive x-ray mapping, it is clarified that the BW is formed by atomic diffusion of Ti atoms from CrTi layer due to the substrate heating process, and a compound consists of Mg, Ti and O atoms. This BW can be used as a template to magnetically isolate the FePt column in the FePt-based granular film, such as FePt-SiO2, if the size of the BW is reduced to less than 10 nm. M-H loop of the FePt-C granular film deposited on the underlayer showed that the nodule and BW induce oxidation of the FePt grains, and reduction of intergranular exchange coupling.

Magnetic characteristics and nanostructures of FePt granular films with GeO2 segregant

Science.gov (United States)

Ono, Takuya; Moriya, Tomohiro; Hatayama, Masatoshi; Tsumura, Kaoru; Kikuchi, Nobuaki; Okamoto, Satoshi; Kitakami, Osamu; Shimatsu, Takehito

2017-01-01

To realize a granular film composed of L10-FePt grains with high uniaxial magnetic anisotropy energy, Ku, and segregants for energy-assisted magnetic recording, a FePt-GeO2/FePt-C stacked film was investigated in the engineering process. The FePt-GeO2/FePt-C stacked film fabricated at a substrate temperature of 450 °C realized uniaxial magnetic anisotropy, Kugrain , of about 2.5 × 107 erg/cm3, which is normalized by the volume fraction of FePt grains, and a granular structure with an averaged grain size of 7.7 nm. As the thickness of the FePt-GeO2 upper layer was increased to 9 nm, the Ku values were almost constant. That result differs absolutely from the thickness dependences of the other oxide segregant materials such as SiO2 and TiO2. Such differences on the oxide segregant are attributed to their chemical bond. The strong covalent bond of GeO2 is expected to result in high Ku of the FePt-GeO2/FePt-C stacked films.

Use of spermicide and impact of prophylactic condom use among sex workers in Santa Fe de Bogota, Colombia.

Science.gov (United States)

Farr, G; Acosta Castro, L A; DiSantostefano, R; Claassen, E; Olguin, F

1996-01-01

Condom use is one of the most important preventive measures sex workers can take to reduce the risk of becoming infected with a sexually transmitted disease. However, a client may refuse to use a condom when requested. Some sexually transmitted disease prevention programs are recommending that sex workers use spermicide as an alternative prophylaxis when a condom is refused, yet little is known about the effect of this recommendation on prophylactic condom use. To determine if using spermicide, either in conjunction with condoms or as a backup, influenced overall condom use among a group of sex workers at high risk of sexually transmitted diseases in Santa Fe de Bogota, Colombia. Participants were assigned randomly to one of three condom use groups: use of condoms only (Condoms Only), use of condoms and spermicides concurrently (Condom and Spermicide), or use of spermicide when condoms were refused (Spermicide as a Backup). A total of 199 sex workers entered the study and were asked to return for follow-up every 2 weeks for a period of 12 weeks. Women assigned to the Spermicide as a Backup group used a condom for an average of 78.1% of their reported acts of intercourse, compared with an average of 94.5% in the Condom Only and 92.3% in the Condom and Spermicide groups. However, women in the Spermicide as a Backup group used a condom or spermicide for an average of 96.9% of their acts of intercourse. Condoms were used for every intercourse act by less than 5% of the women in the Spermicide as a Backup groups, compared with 50.7% in the Condom Only group and 41.2% in the Condom and Spermicide group (P 0.001). When condoms were not used, client refusal was the primary reason reported. The incidence of sexually transmitted diseases and other urogenital inflammations in all groups was lower than expected. Among Colombian sex workers, condom use declined substantially when women were instructed to use spermicides if they were unable to persuade their partner to use a

Magnetic SiO2/Fe3O4 colloidal crystals

International Nuclear Information System (INIS)

Huang, C-K; Hou, C-H; Chen, C-C; Tsai, Y-L; Chang, L-M; Wei, H-S; Hsieh, K-H; Chan, C-H

2008-01-01

We proposed a novel technique to fabricate colloidal crystals by using monodisperse SiO 2 coated magnetic Fe 3 O 4 (SiO 2 /Fe 3 O 4 ) microspheres. The magnetic SiO 2 /Fe 3 O 4 microspheres with a diameter of 700 nm were synthesized in the basic condition with ferric sulfate, ferrous sulfate, tartaric acid and tetraethyl orthosilicate (TEOS) in the reaction system. Monodisperse SiO 2 /Fe 3 O 4 superparamagnetic microspheres have been successfully used to fabricate colloidal crystals under the existing magnetic field

Supplying Fe from molten coal ash to revive kelp community

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, K.; Yamamoto, M.; Sadakata, M. [University of Tokyo, Tokyo (Japan)

2006-02-15

The phenomenon of a kelp-dominated community changing to a crust-dominated community, which is called 'barren-ground', is progressing in the world, and causing serious social problems in coastal areas. Among several suggested causes of 'barren-ground', we focused on the lack of Fe in seawater. Kelp needs more than 200 nM of Fe to keep its community. However there are the areas where the concentration of Fe is less than 1 nM, and the lack of Fe leads to the 'barren-ground.' Coal ash is one of the appropriate materials to compensate the lack of Fe for the kelp growth, because the coal ash is a waste from the coal combustion process and contains more than 5 wt% of Fe. The rate of Fe elution from coal fly ash to water can be increased by 20 times after melting in Ar atmosphere, because 39 wt% of the Fe(III) of coal fly ash was reduced to Fe(II). Additionally molten ash from the IGCC (integrated coal gasification combined cycle) furnace in a reducing atmosphere and one from a melting furnace pilot plant in an oxidizing atmosphere were examined. Each molten ash was classified into two groups; cooled rapidly with water and cooled slowly without water. The flux of Fe elution from rapidly cooled IGCC molten ash was the highest; 9.4 x 10{sup -6} g m{sup -2} d{sup -1}. It was noted that the coal ash melted in a reducing atmosphere could elute Fe effectively, and the dissolution of the molten ash itself controlled the rate of Fe elution in the case of rapidly cooled molten ash.

A sensitive and selective sensor for biothiols based on the turn-on fluorescence of the Fe-MIL-88 metal-organic frameworks-hydrogen peroxide system.

Science.gov (United States)

Sun, Zheng Juan; Jiang, Jun Ze; Li, Yuan Fang

2015-12-21

Herein, we present a novel strategy based on a "turn-on" fluorescence system made up of metal-organic frameworks Fe-MIL-88 and H2O2 for detecting biothiols in human serum. The nonfluorescent Fe-MIL-88 gives weak fluorescence in the presence of H2O2. Interestingly, it was found that biothiols such as glutathione (GSH), cysteine (Cys) or homocysteine (Hcy) could induce fluorescence turn-on of the Fe-MIL-88/H2O2 system. Under optimal conditions, the relative fluorescence intensity exhibited a good linear relationship in the range from 50 nM-10 μM for GSH (r = 0.994), 50 nM-10 μM for Cys (r = 0.990), and 50 nM-10 μM (r = 0.992) for Hcy; the detection limits of GSH, Cys and Hcy were 30 nM, 40 nM, and 40 nM respectively. Mechanism investigation reveals that biothiols could associate with Fe-MIL-88 via hydrogen bonding and electrostatic interaction followed by redox reaction between biothiols and Fe(3+) present in the Fe-MIL-88, Fe(3+) was thus reduced to Fe(2+), and then Fe(2+) could efficiently catalyze the decomposition of H2O2 to yield ˙OH radicals through the Fenton reaction. Besides, biothiols were able to reduce H2O2 to produce ˙OH radicals directly. Thus the Fe-MIL-88 as well as biothiols could cooperatively contribute to the activation of H2O2 to generate higher amounts of ˙OH radicals, which in turn oxidize the free ligand terephthalic acid (BDC) outside or within the Fe-MIL-88 structure to strongly fluorescent hydroxylated terephthalic acid (OHBDC), thereby turning on the fluorescence.

Effect of magnetic fullerene on magnetization reversal created at the Fe/C60 interface.

Science.gov (United States)

Mallik, Srijani; Mattauch, Stefan; Dalai, Manas Kumar; Brückel, Thomas; Bedanta, Subhankar

2018-04-03

Probing the hybridized magnetic interface between organic semiconductor (OSC) and ferromagnetic (FM) layers has drawn significant attention in recent years because of their potential in spintronic applications. Recent studies demonstrate various aspects of organic spintronics such as magnetoresistance, induced interface moment etc. However, not much work has been performed to investigate the implications of such OSC/FM interfaces on the magnetization reversal and domain structure which are the utmost requirements for any applications. Here, we show that non-magnetic Fullerene can obtain non-negligible magnetic moment at the interface of Fe(15 nm)/C 60 (40 nm) bilayer. This leads to substantial effect on both the magnetic domain structure as well as the magnetization reversal when compared to a single layer of Fe(15 nm). This is corroborated by the polarized neutron reflectivity (PNR) data which indicates presence of hybridization at the interface by the reduction of magnetic moment in Fe. Afterwards, upto 1.9 nm of C 60 near the interface exhibits magnetic moment. From the PNR measurements it was found that the magnetic C 60 layer prefers to be aligned anti-parallel with the Fe layer at the remanant state. The later observation has been confirmed by domain imaging via magneto-optic Kerr microscopy.

The structure and electronic properties of hexagonal Fe{sub 2}Si

Energy Technology Data Exchange (ETDEWEB)

Tang, Chi Pui; Tam, Kuan Vai; Zhang, Xiaoping, E-mail: xpzhang@must.edu.mo [Lunar and Planetary Science Laboratory, Macau University of Science and Technology, Macau (Macao); Xiong, Shi Jie [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Cao, Jie [College of Science, Hohai University, Nanjing 211171 (China)

2016-06-15

On the basis of first principle calculations, we show that a hexagonal structure of Fe{sub 2}Si is a ferromagnetic crystal. The result of the phonon spectra indicates that it is a stable structure. Such material exhibits a spin-polarized and half-metal-like band structure. From the calculations of generalized gradient approximation, metallic and semiconducting behaviors are observed with a direct and nearly 0 eV band gap in various spin channels. The densities of states in the vicinity of the Fermi level is mainly contributed from the d-electrons of Fe. We calculate the reflection spectrum of Fe{sub 2}Si, which has minima at 275 nm and 3300 nm with reflectance of 0.27 and 0.49, respectively. Such results may provide a reference for the search of hexagonal Fe{sub 2}Si in experiments. With this band characteristic, the material may be applied in the field of novel spintronics devices.

Environmental Assessment of Proposed White Lakes Drop Zones for Kirtland Air Force Base

Science.gov (United States)

2005-09-01

measuring 2’ X 3’, filled with rubber ballast (each weighing approximately 45 pounds [lbs]). Half of these drops would occur with parachutes...Santa Fe, NM Rayo McCollough Data Services Manager New Mexico Natural Heritage Program UNM Biology Dept. University of New Mexico Terry...5270 Mr. Rayo McCollough Information Coordinator Natural Heritage New Mexico UNM Biology Department MSC03 2020 1 University of New Mexico

Climate Change Impacts on Water and Energy for Army Installations

Science.gov (United States)

2015-09-01

CO; Houston, TX; Santa Fe, NM, Salt Lake City, UT; Carson City and Los Vegas, NV; and San Fran- cisco , CA (Melillo, Richmond, and Yohe 2014). This...United States, have already affected the Bonneville Power Administration (BPA). BPA markets electric power from the Bonneville Dam located on the...the electricity generated in the Electricity Market Module (EMM) region* and therefore this work’s forecast of the increase in future electricity gen

All-epitaxial Co{sub 2}FeSi/Ge/Co{sub 2}FeSi trilayers fabricated by Sn-induced low-temperature epitaxy

Energy Technology Data Exchange (ETDEWEB)

Kawano, M.; Ikawa, M.; Arima, K.; Yamada, S.; Kanashima, T.; Hamaya, K., E-mail: hamaya@ee.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka 560-8531 (Japan)

2016-01-28

We demonstrate low-temperature growth of all-epitaxial Co{sub 2}FeSi/Ge/Co{sub 2}FeSi trilayer structures by developing Sn-induced surfactant-mediated molecular beam epitaxy (SMBE) of Ge on Co{sub 2}FeSi. Despite the growth of a semiconductor on a metal, we verify that the inserted Sn monolayers between Ge and Co{sub 2}FeSi enable to promote the 2D epitaxial growth of Ge up to 5 nm at a T{sub G} of 250 °C. An understanding of the mechanism of the Sn-induced SMBE leads to the achievement of all-epitaxial Co{sub 2}FeSi/Ge/Co{sub 2}FeSi trilayer structures with spin-valve-like magnetization reversals. This study will open a way for vertical-type and high-performance Ge-based spintronics devices.

Novel method of room temperature ionic liquid assisted Fe3O4 nanocubes and nanoflakes synthesis

International Nuclear Information System (INIS)

Ramalakshmi, M.; Shakkthivel, P.; Sundrarajan, M.; Chen, S.M.

2013-01-01

Graphical abstract: - Highlights: • First time [Bmim][TfO] IL is used for the Fe 3 O 4 nanoparticle synthesis. • Novel method tunes Fe 3 O 4 nanocubes and nanoflakes forms influenced by the base and IL. • Fe 3 O 4 oxidized topotactically into γ-Fe 2 O 3 nanoparticles by annealing and base. • Uniform morphology with average size of 33 nm negligible superstructure are formed. • Ms values are characterized by thin layer of γ-Fe 2 O 3 on the nanoparticle surface. - Abstract: For the first time, the nanomagnetite superparamagnetic particles are successfully synthesized by precipitation method using 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim][TfO] ionic liquid medium/surfactant. The obtained Fe 3 O 4 particles are nanocubes and nanoflakes and this formation is influenced by the base concentration and anisotropic circumstances produced by the ionic liquid and their size varies from 20 nm to 150 × 300 nm (width × length). The synthesized magnetite nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) studies. The results show that the core of the Fe 3 O 4 nanoparticles is surrounded by a thin layer of γ-Fe 2 O 3 by topotactical partial oxidation, which is remarkably proceed with the subsequent calcination. The magnetite nanocubes have high saturation magnetization value and exhibit superparamagnetic hysteresis loop

Structural-phase changes of α-Fe implanted with high ion doses

International Nuclear Information System (INIS)

Ivanov, Y.F.; Pogrebnyak, A.; Martynenko, V.

2001-01-01

The CEMS method was used to examine and implanted layer of α-Fe with a thickness of up to 100 nm. The radiation of α-Fe with carbon ions results of the formation of the solid solution of carbon in α-Fe and the precipitation of the iron carbides Fe 2 C. The implantation of aluminium in the α-Fe is accompanied by the formation of the order phase Fe 3 Al. The results of show that the phase the composition of the surface layer of α-Fe, irradiated with titanium, is represented by the solid solution of the titanium in α-Fe, and also by the micro-clusters of iron characterised by different environment of the titanium atoms of the level of several co-ordination spheres. The presence of these micro-clusters indicates the non-uniform distribution of titanium in α-Fe. The additional Auger analysis of the specimens of α-Fe, implanted with titanium with a dose of 5 x 10 -17 cm -2 , showed a high concentration of carbon (up to 20 at.%) in the layer up to 50 nm thick. The authors of 2 assumed that the carbon, implanted from the residual atmosphere, affects not only the resultant profile of the distribution of titanium in the depth of α-Fe, but also the change of the physical-mechanical properties of the surface layer. The main aim of the investigations was to examine the phase composition and the formation of secondary defects (dislocations and dislocation sub structures) in the surface layer of α-Fe, implanted with titanium, aluminium, carbon, with a dose of 5 x 10 -17 cm -2

Investigating the Interaction of Fe Nanoparticles with Lysozyme by Biophysical and Molecular Docking Studies.

Directory of Open Access Journals (Sweden)

Zahra Aghili

Full Text Available Herein, the interaction of hen egg white lysozyme (HEWL with iron nanoparticle (Fe NP was investigated by spectroscopic and docking studies. The zeta potential analysis revealed that addition of Fe NP (6.45±1.03 mV to HEWL (8.57±0.54 mV can cause to greater charge distribution of nanoparticle-protein system (17.33±1.84 mV. In addition, dynamic light scattering (DLS study revealed that addition of Fe NP (92.95±6.11 nm to HEWL (2.68±0.37 nm increases suspension potential of protein/nanoparticle system (51.17±3.19 nm. Fluorescence quenching studies reveled that both static and dynamic quenching mechanism occur and hydrogen bond and van der Waals interaction give rise to protein-NP system. Synchronous fluorescence spectroscopy of HEWL in the presence of Fe NP showed that the emission maximum wavelength of tryptophan (Trp residues undergoes a red-shift. ANS fluorescence data indicated a dramatic exposure of hydrophobic residues to the solvent. The considerable reduction in melting temperature (T(m of HEWL after addition of Fe NP determines an unfavorable interaction system. Furthermore circular dichoroism (CD experiments demonstrated that, the secondary structure of HEWL has not changed with increasing Fe NP concentrations; however, some conformational changes occur in tertiary structure of HEWL. Moreover, protein-ligand docking study confirmed that the Fe NP forms hydrogen bond contacts with HEWL.

Synthesis of Fe2O3/TiO2 nanorod-nanotube arrays by filling TiO2 nanotubes with Fe

International Nuclear Information System (INIS)

Mohapatra, Susanta K; Banerjee, Subarna; Misra, Mano

2008-01-01

Synthesis of hematite (α-Fe 2 O 3 ) nanostructures on a titania (TiO 2 ) nanotubular template is carried out using a pulsed electrodeposition technique. The TiO 2 nanotubes are prepared by the sonoelectrochemical anodization method and are filled with iron (Fe) by pulsed electrodeposition. The Fe/TiO 2 composite is then annealed in an O 2 atmosphere to convert it to Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The length of the Fe 2 O 3 inside the TiO 2 nanotubes can be tuned from 50 to 550 nm by changing the deposition time. The composite material is characterized by scanning electron microscopy, transmission electron microscopy and diffuse reflectance ultraviolet-visible studies to confirm the formation of one-dimensional Fe 2 O 3 /TiO 2 nanorod-nanotube arrays. The present approach can be used for designing variable one-dimensional metal oxide heterostructures

Pelas trilhas da ILha de Santa Catarina

OpenAIRE

Silveira, Flavio Leonel Abreu da

1996-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciencias Humanas O estudo sobre o ecoturismo na Ilha de Santa Catarina vem demonstrar o surgimento de novas modalidades turísticas entre os grupos urbanos. A pesquisa aponta para a intersecção entre lazer, turismo, ecologia e esporte, demonstrando a importân-cia das práticas ecoturísticas na atualidade. A partir de tal perspectiva, as questões de gênero surgem com significativa relevância. Estamos frente...

Ion irradiation effects on high purity bcc Fe and model FeCr alloys

International Nuclear Information System (INIS)

Bhattacharya, Arunodaya

2014-01-01

irradiated FeCr alloys, and the results were compared to bcc Fe. The analysis was performed at an intermediate depth 300 - 400 nm below the surface (to avoid injected interstitial effect and surface effects), corresponding to 128 dpa, 13 appm He/dpa. TEM study revealed that the addition of small quantities of Cr, as low as 3 wt.%, is highly efficient in strongly reducing void swelling. It was achieved by a drastic reduction of cavity sizes. For instance, average cavity size in Fe3%Cr was 0.9 nm as opposed to 6.8 nm in bcc Fe. Furthermore, the variation of void swelling as a function of Cr content is non-monotonic, with a local maxima around 9 -10 wt.% Cr. 3) Coupling of conventional TEM, STEM/EDS and APT analysis on low and intermediate dose irradiated FeCr alloys revealed the presence of Cr enriched zones on the habit plane of the dislocation loops. This is expected to be due to radiation induced segregation (RIS) of Cr close to the core of the loops. As the loop grows under irradiation, the segregated areas are probably prevented from re-dissolution by impurity elements such as C. When imaged by TEM using classical diffraction contrast imaging techniques, these enriched zones produce displacement fringe contrast on the loop plane. A quantitative estimate of this enrichment was deduced by STEM/EDS and APT. The Cr content in these areas was between 23 - 35 at.% measured by EDS and 22 ± 2 at.% obtained by APT, which is well below the Cr content of the Cr-rich α' phase. (author) [fr

Free inside: The Music Class at Santa Ana Jail

Science.gov (United States)

Fierro, Joe

2010-01-01

This article examines the workings of the music class at the Santa Ana Jail in Santa Ana, California. It gives us insight into a jail system and a music class focused on helping inmates position themselves to become productive members of society. In this article I examine how the facility encourages inmates' good behaviour and why the music class…

Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.

Science.gov (United States)

Zhao, Cen; Arroyo-Mora, Luis E; DeCaprio, Anthony P; Sharma, Virender K; Dionysiou, Dionysios D; O'Shea, Kevin E

2014-12-15

Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (OH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.19 ± 0.12 and 0.30 ± 0.01 μM/min, respectively. The steady-state concentration of hydroxyl radical (OH) for the Fe(III)-oxalate/H2O2/UV (350 nm) conditions was 10.88 ± 1.13 × 10(-14) M and 2.7 ± 0.1 × 10(-14) M for the Fe(III)-oxalate/H2O2/visible (450 nm). The rate of superoxide anion radical (O2(-)) production under Fe(III)-oxalate/H2O2/UV (350 nm) was 0.19 ± 0.02 μM/min with a steady-state concentration of 5.43 ± 0.473 × 10(-10) M. Detailed product studies using liquid chromatography coupled to Q-TOF/MS demonstrate both reduction (multiple dehalogenations) and oxidation (aromatic ring and side chains) contribute to the degradation pathways. The reduction processes appear to be initiated by the carbon dioxide anion radical (CO2(-)) while oxidation processes are consistent with OH initiated reaction pathways. Unlike most advanced oxidation processes the Fe(III)-oxalate/H2O2/photochemical system can initiate to both reductive and oxidative degradation processes. The observed reductive dehalogenation is an attractive remediation strategy for halogenated organic compounds as the process can dramatically reduce the formation of the problematic disinfection by-products often associated with oxidative treatment processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Physical data of soil profiles formed on late Quaternary marine terraces near Santa Cruz, California

Science.gov (United States)

Munster, Jennie; Harden, Jennifer W.

2002-01-01

last site selected, and this report contains minimal data on this terrace. Sites on the second, third, and fourth terraces are located in Wilder Ranch, Santa Cruz, California. Site five is on private property north of Wilder Ranch. Careful consideration was taken in selecting field sites, choosing locations in a topographically flat area to avoid effects of erosion, and trying to keep parent material similar. This report contains physical properties of the soil profiles on four of the five marine terraces near Santa Cruz, California, excluding the youngest terrace in all tables except 6 and 7. Data includes field descriptions, bulk density, grain size analyses, weight percent magnetic fraction, and the soil development index. Soil properties are important when trying to understand the chemistry of a given profile or when comparing profiles. Grain size constrains the movement of water in a profile, thus controlling movement of chemicals and weathering rates. Bulk density is a useful property to calculate chemical inventory. Quantifying the magnetic fraction aids in understanding the Fe inventory for these soils. The soil development index is a semi-quantitative way to define the degree of development of a soil profile. This is a useful way to compare development of profiles for this chronosequence or compare the Santa Cruz terraces to a suit of other terraces or another chronosequence.

Study of Nd-Fe-B alloys with nonstoichiometric Nd content in optimal magnetic state

Directory of Open Access Journals (Sweden)

Ćosović V.

2009-01-01

Full Text Available Characterization of two rapid-quenched Nd-Fe-B alloys with nonstoichiometric Nd content in the optimized magnetic state was carried out using the X-ray diffractometry (XRD, 57Fe Mössbauer spectroscopic phase analysis (MS, electron microscopy (TEM, high resolution TEM (HREM and Superconducting Quantum Interference Device (SQUID magnetometer. The experimental results demonstrate the fundamental difference in the structure and magnetic properties of the two investigated alloys in the optimized magnetic state. The Nd-Fe-B alloy with the reduced Nd content (Nd4.5Fe77B18.5 was found to have the nanocomposite structure of Fe3B/Nd2Fe14B and partly α-Fe/Nd2Fe14B, with mean grain size below 30 nm. On the other side, the overstoichiometric Nd14Fe79B7 alloy has almost a monophase structure with the dominant content of the hard magnetic phase Nd2Fe14B (up to 95 wt. % and a mean crystallite size about 60 nm, as determined by XRD and TEM analysis. The results of magnetic measurements on SQUID magnetometer also suggest the nanocomposite structure of the Nd-low alloy and nanocrystalline decoupled structure of the Nd-rich alloy after the optimal heat treatment.

From core/shell to hollow Fe/γ-Fe_2O_3 nanoparticles: evolution of the magnetic behavior

International Nuclear Information System (INIS)

Nemati, Z; Khurshid, H; Alonso, J; Phan, M H; Mukherjee, P; Srikanth, H

2015-01-01

High quality Fe/γ-Fe_2O_3 core/shell, core/void/shell, and hollow nanoparticles with two different sizes of 8 and 12 nm were synthesized, and the effect of morphology, surface and finite-size effects on their magnetic properties including the exchange bias (EB) effect were systematically investigated. We find a general trend for both systems that as the morphology changes from core/shell to core/void/shell, the magnetization of the system decays and inter-particle interactions become weaker, while the effective anisotropy and the EB effect increase. The changes are more drastic when the nanoparticles become completely hollow. Noticeably, the morphological change from core/shell to hollow increases the mean blocking temperature for the 12 nm particles but decreases for the 8 nm particles. The low-temperature magnetic behavior of the 12 nm particles changes from a collective super-spin-glass system mediated by dipolar interactions for the core/shell nanoparticles to a frustrated cluster glass-like state for the shell nanograins in the hollow morphology. On the other hand for the 8 nm nanoparticles core/shell and hollow particles the magnetic behavior is more similar, and a conventional spin glass-like transition is obtained at low temperatures. In the case of the hollow nanoparticles, the coupling between the inner and outer spin layers in the shell gives rise to an enhanced EB effect, which increases with increasing shell thickness. This indicates that the morphology of the shell plays a crucial role in this kind of exchange-biased systems. (paper)

Spectroscopic ellipsometry study of FePt nanoparticle films

Energy Technology Data Exchange (ETDEWEB)

Lee, S.J.; Lo, C.C.H. [Ames Laboratory, Iowa State University, Ames, IA 50011 (United States); Yu, A.C.C. [Sony Corporation, Sendai Technology Center, 3-4-1 Sakuragi, Miyagi 985-0842 (Japan); Fan, M. [School of Materials Science and Technology, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2006-12-15

The optical properties of a FePt nanoparticle film were investigated using spectroscopic ellipsometry. The FePt nanoparticle film of thickness about 15 nm was prepared by deposition of FePt nanoparticles directly on a Si substrate. The nanoparticle film was annealed at 600 C in vacuum for two hours before the measurements. The optical properties of the FePt nanoparticle film showed distinctively different spectra from those obtained from the bulk and thin film FePt samples, in particular in the low photon energy range (below 3.5 eV) where the nanoparticle film exhibited a relatively flat refractive index and a substantially lower extinction coefficient than the bulk and epitaxial thin film samples. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Effect of heat treatment on interface driven magnetic properties of CoFe films

Science.gov (United States)

Singh, Akhilesh Kr.; Hsu, Jen-Hwa

2017-06-01

We report systematic studies on non-magnetic Ta underlayer and cap layer driven microstructural and magnetic properties at a wide temperature range for CoFe films. All the films were grown at room temperature and post annealed at different annealing temperatures (TA = 200 °C, 250 °C, 300 °C, 350 °C, 400 °C and 450 °C). The in-plane magnetic hysteresis (M-H) loops of 10 nm thick CoFe single layer films, grown directly on thermally oxidized Si substrate, exhibit anisotropic nature for TA above 250 °C. However, the CoFe (10 nm) films grown on the 5 nm thick Ta underlayer show reduced anisotropy. Moreover, with underlayer and cap layers (2 nm) the anisotropy is disappeared. The in-plane coercivity (HC) shows a strong variation with TA, underlayer and cap layers. HC increases significantly with Ta underlayer and cap layers. The out of plane M-H loops exhibit increase in the remanence magnetization and squareness with both Ta underlayer and cap layers due to transition of in-plane magnetization component to the out of plane direction. The atomic force microscopic observations revealed that grain/particle size and shape depend strongly on TA and Ta layers. Moreover, a large reduction in the surface roughness is observed with the Ta cap layer. The magnetic domain patterns depend on the TA, and Ta layers. However, for Ta/CoFe/Ta films no clear domains were observed for all the TA. Hence, the Ta cap layers not only protect the CoFe magnetic layer against the heat treatment, but also show a smooth surface at a wide temperature range. These results could be discussed on the basis of random anisotropy model, TA, underlayer and cap layers driven microstructure and magnetization orientation of the CoFe films.

Highly selective ratiometric fluorescent detection of Fe{sup 3+} with a polyphenyl derivative

Energy Technology Data Exchange (ETDEWEB)

Li, Zhan-Xian, E-mail: lizx@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhou, Wan; Zhang, Li-Feng; Yuan, Rui-Li; Liu, Xing-Jiang; Wei, Liu-He [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Yu, Ming-Ming, E-mail: yumm@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

2013-04-15

Compared with other fluorescent probes, ratiometric fluorescence responses are more attractive because the ratio between the two emission intensities can be used to measure the analyte concentration and provide a built-in correction for environmental effects. A highly selective and sensitive ratiometric fluorescent probe for Fe{sup 3+} was synthesized, which exhibits an enhanced fluorescence with a large red-shift in emission from 361 to 455 nm upon addition of Fe{sup 3+}. The red-shift of the emission peak can be ascribed to the reformed orbital, and the increase of emission intensity may be ascribed to the inhibition of the rotation of C–C bonds between each two aromatic rings. -- Graphical abstract: A highly selective and sensitive ratiometric fluorescent probe for Fe{sup 3+} was synthesized, which exhibits an enhanced fluorescence with a large red-shift in emission from 361 to 455 nm upon addition of Fe{sup 3+}. Highlights: ► A ratiometric fluorescent probe for Fe{sup 3+} was synthesized. ► The probe exhibits an enhanced fluorescence with a red-shift upon addition of Fe{sup 3+}. ► Inhibition of the rotation of C–C bonds was possible detection mechanism for Fe{sup 3+}.

Growth of Ferromagnetic Epitaxial Film of Hexagonal FeGe on (111) Ge Surface

Science.gov (United States)

Kumar, Dushyant; Joshi, P. C.; Hossain, Z.; Budhani, R. C.

2014-03-01

The realization of semiconductors showing ferromagnetic order at easily accessible temperatures has been of interest due to their potential use in spintronic devices where long spin life times are of key interest. We have realized the growth of FeGe thin films on Ge (111) wafers using pulsed laser deposition (PLD). The stoichiometric and single phase FeGe target used in PLD chamber has been made by arc melting. A typical θ-2 θ diffraction spectra performed on 40 nm thick FeGe film suggests the stabilization of β-Ni2In (B82-type) hexagonal phase with an epitaxial orientation of (0001)FeGe ||(111)Ge and [11-20]FeGe ||[-110]Ge. SEM images shows a granular structure with the formation of very large grains of about 100 to 500 nm in lateral dimension. The magnetization vs. temperature data taken from SQUID reveal the TC of ~ 270K. Since, PLD technique makes it easier to stabilize the B82 (Ni2In) hexagonal phase in thin FeGe films, this work opens opportunities to reinvestigate many conflicting results on various properties of the FeGe system.

Permanent magnetic properties of NdFe12Nx sputtered films epitaxially grown on V buffer layer

Science.gov (United States)

Sato, T.; Ohsuna, T.; Yano, M.; Kato, A.; Kaneko, Y.

2017-08-01

To clarify the magnetic properties of the NdFe12Nx compound, which shows promise as a high-performance permanent magnet material, NdFe12Nx epitaxial films fabricated by using a V underlayer on MgO (100) single-crystalline substrates were investigated. Nd-Fe films deposited on a V underlayer consist of NdFe12 grains, which have a c-axis orientation perpendicular to the film plane, as well as α-Fe and Nd2Fe17 phases. In the Nd-Fe-N film obtained by subsequent nitridation of the Nd-Fe film, NdFe12Nx grains grew as the dominant phase, and the volume fractions of α-Fe phases dropped below 5%. A Nd-Fe-N film with a thickness of 50 nm exhibits a saturation magnetization (Ms) of 1.7 T, an anisotropy field (HA) of ˜60 kOe, a magnetocrystalline anisotropy energy (K1) of ˜4.1 MJ/m3, and a coercivity (Hc) of 1.7 kOe. The Hc of a Nd-Fe-N film with a thickness of 25 nm is 4.3 kOe. These results indicate that NdFe12Nx compounds have a superior Ms compared to Nd-Fe-B magnets, while the enhancement in Hc is indispensable.

Bacteria-assisted preparation of nano α-Fe{sub 2}O{sub 3} red pigment powders from waste ferrous sulfate

Energy Technology Data Exchange (ETDEWEB)

Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui, E-mail: zhangyongkui@scu.edu.cn

2016-11-05

Highlights: • A route to prepare nano α-Fe{sub 2}O{sub 3} red pigment from waste ferrous sulfate is proposed. • Acidithiobacillus ferrooxidans is introduced for accelerating iron oxidation. • The particle size of synthetic α-Fe{sub 2}O{sub 3} is ranged from 22 nm to 86 nm. • The prepared nano α-Fe{sub 2}O{sub 3} red pigment fulfills ISO 1248-2006. - Abstract: Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe{sub 2}O{sub 3} red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe{sub 2}O{sub 3} red pigment powders contained 98.24 wt.% of Fe{sub 2}O{sub 3} were successfully prepared, with a morphology of spheroidal and particle size ranged from 22 nm to 86 nm and averaged at 45 nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments.

Noteworthy bird records at Lagoa Santa, southeastern Brazil Registros notáveis de aves em Lagoa Santa, sudeste do Brasil

OpenAIRE

Marcos Rodrigues

2008-01-01

Lagoa Santa, a small town in southeastern Brazil where naturalist Peter Lund lived, is regarded nowadays as an important historical site for the biological sciences. From 1847 to 1855, J.T. Reinhardt, hosted by Lund, collected 343 bird species. This material is an outstanding reference for many modern ornithological studies. The present paper reports the occurrence of some rare and threatened birds for the region of Lagoa Santa between 1998 and 2005. In this account I list the Rusty-margined ...

Microstructure and magnetic properties of Sm(CobalFexCu0.128Zr0.02)7.0 magnets with Fe substitution

International Nuclear Information System (INIS)

Tang, W.; Zhang, Y.; Hadjipanayis, G.C.

2000-01-01

The effect of Fe substitution on the microstructure and magnetic properties of Sm(Co bal Fe x Cu 0.128 Zr 0.02 ) 7.0 magnets was systematically studied. With increasing Fe content (x=0-0.25), the cellular structure changes from a fine inhomogeneous (the average cell size is 25 nm.) to a larger but uniform cell size (120 nm), and finally to coarse and inhomogeneous (180 nm). The coercivity gradually increases reaching an optimal value of 30 kOe with x=0.2, and then drops sharply with further Fe increase. These results suggest that Fe mainly goes into the 2 : 17R structure and stabilizes the phase. The addition of a certain amount of Fe is necessary to develop a uniform cellular with a larger cell size and thus a high coercivity. The excessive addition of Fe hinders the transformation of 2 : 17R to 2 : 17H structure during a solid solution and leads to the disappearance of the cellular microstructure and deterioration of coercivity

Origin of magnetostriction in Fe-Ga

DEFF Research Database (Denmark)

Mudivarthi, Chaitanya; Laver, Mark; Cullen, James

2010-01-01

This paper investigates the origin of large magnetostriction in Fe-Ga alloys using small-angle neutron scattering (SANS) and Kerr microscopy. The SANS data for a single-crystal, electron irradiated, and quenched Fe81Ga19 sample under externally applied magnetic and elastic fields revealed...... the existence of magnetostrictive nanoclusters spaced at similar to 15 nm apart that have a different magnetization than the A2 matrix. Combining the SANS results and the magnetization orientation obtained from the magnetic domain images using a Kerr microscope, it appears that the nanoclusters contribute...

Facile synthesis of Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet as high-performance anode for lithium-ion batteries

Science.gov (United States)

Zhang, Dan; Li, Guangshe; Yu, Meijie; Fan, Jianming; Li, Baoyun; Li, Liping

2018-04-01

Iron nitrides are considered as highly promising anode materials for lithium-ion batteries because of their nontoxicity, high abundance, low cost, and higher electrical conductivity. Unfortunately, their limited synthesis routes are available and practical application is still hindered by their fast capacity decay. Herein, a facile and green route is developed to synthesize Fe4N/Fe2O3/Fe/porous N-doped carbon nanosheet composite. The size of Fe4N/Fe2O3/Fe particles is small (10-40 nm) and they are confined in porous N-doped carbon nanosheet. These features are conducive to accommodate volume change well, shorten the diffusion distance and further elevate electrical conductivity. When tested as anode material for lithium-ion batteries, a high discharge capacity of 554 mA h g-1 after 100 cycles at 100 mA g-1 and 389 mA h g-1 after 300 cycles at 1000 mA g-1 are retained. Even at 2000 mA g-1, a high capacity of 330 mA h g-1 can be achieved, demonstrating superior cycling stability and rate performance. New prospects will be brought by this work for the synthesis and the potential application of iron nitrides materials as an anode for LIBs.

Sub-50 nm patterning of functional oxides by soft lithographic edge printing

NARCIS (Netherlands)

George, A.; ten Elshof, Johan E.

2012-01-01

We report a fast, versatile and reproducible method to make arbitrary nanoscale patterns of functional metal oxides by edge transfer printing of aqueous metal-loaded water-soluble polyacrylic acid (PAA) solutions on silicon. Patterns of ZnO, CuO, NiO and Fe2O3 with lateral dimensions below 50 nm

XRD analysis of undoped and Fe doped TiO2 nanoparticles by Williamson Hall method

International Nuclear Information System (INIS)

Bharti, Bandna; Barman, P. B.; Kumar, Rajesh

2015-01-01

Undoped and Fe doped titanium dioxide (TiO 2 ) nanoparticles were synthesized by sol-gel method at room temperature. The synthesized samples were annealed at 500°C. For structural analysis, the prepared samples were characterized by X-ray diffraction (XRD). The crystallite size of TiO 2 and Fe doped TiO 2 nanoparticles were calculated by Scherer’s formula, and was found to be 15 nm and 11 nm, respectively. Reduction in crystallite size of TiO 2 with Fe doping was observed. The anatase phase of Fe-doped TiO 2 nanoparticles was also confirmed by X-ray diffraction. By using Williamson-Hall method, lattice strain and crystallite size were also calculated. Williamson–Hall plot indicates the presence of compressive strain for TiO 2 and tensile strain for Fe-TiO 2 nanoparticles annealed at 500°C

Mechanically activated synthesis of nanocrystalline ternary carbide Fe3Mo3C

International Nuclear Information System (INIS)

Zakeri, M.; Rahimipour, M.R.; Khanmohammadian, A.

2008-01-01

In this investigation, Fe 3 Mo 3 C ternary carbide was synthesized from the elemental powders of 3Mo/3Fe/C by mechanical milling and subsequent heat treatment. Structural and morphological evolutions of powders were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that no phase transformation occurs during milling. A nanostructure Mo (Fe) solid solution obtained after 30 h of milling. With increasing milling time to 70 h no change takes place except grain size reduction to 9 nm and strain enhancement to 0.86%. Milled powders have spheroid shape and very narrow size distribution about 2 μm at the end of milling. Fe 3 Mo 3 C was synthesized during annealing of 70 h milled sample at 700 deg. C. Undesired phases of MoOC and Fe 2 C form at 1100 deg. C. No transformation takes place during annealing of 10 h milled sample at 700 deg. C. Mean grain size and strain get to 69 nm and 0.23% respectively with annealing of 70 h milled sample at 1100 deg. C

California State Waters Map Series: offshore of Santa Barbara, California

Science.gov (United States)

Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Greene, H. Gary; Krigsman, Lisa M.; Kvitek, Rikk G.; Dieter, Bryan E.; Endris, Charles A.; Seitz, Gordon G.; Sliter, Ray W.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Wong, Florence L.; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Conrad, James E.; Cochran, Susan A.; Johnson, Samuel Y.; Cochran, Susan A.

2013-01-01

In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar data, acoustic backscatter, seafloor video, seafloor photography, high-resolution seismic-reflection profiles, and bottom-sediment sampling data. The map products display seafloor morphology and character, identify potential marine benthic habitats, and illustrate both the surficial seafloor geology and shallow (to about 100 m) subsurface geology. The Offshore of Santa Barbara map area lies within the central Santa Barbara Channel region of the Southern California Bight. This geologically complex region forms a major biogeographic transition zone, separating the cold-temperate Oregonian province north of Point Conception from the warm-temperate California province to the south. The map area is in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland. Significant clockwise rotation—at least 90°—since the early Miocene has been proposed for the Western Transverse Ranges province, and geodetic studies indicate that the region is presently undergoing north-south shortening. Uplift rates (as much as 2.2 mm/yr) that are based on studies of onland marine terraces provide further evidence of significant shortening. The city of Santa Barbara, the main coastal population center in the map area, is part of a contiguous urban area that extends from Carpinteria to Goleta. This urban area was developed on the coalescing alluvial surfaces, uplifted marine terraces, and low hills that lie south of the east-west-trending Santa Ynez Mountains. Several beaches line the actively

Influence of Ba/Fe mole ratios on magnetic properties, crystallite size and shifting of X-ray diffraction peaks of nanocrystalline BaFe12O19 powder, prepared by sol gel auto combu

Science.gov (United States)

Suastiyanti, Dwita; Sudarmaji, Arif; Soegijono, Bambang

2012-06-01

Barium hexaferrite BaFe12O19 (BFO) is of great importance as permanent magnets, particularly for magnetic recording as well as in microwave devices. Nano-crystalline BFO powders were prepared by sol gel auto combustion method in citric acid - metal nitrates system. Hence the mole ratios of Ba/Fe were variated at 1:12; 1:11.5 and 1:11. Ratio of cation to fuel was fixed at 1:1. An appropriate amount of amonia solution was added dropwise to this solution with constant stirring until the PH reached 7 in all cases. Heating at 850oC for 10 hours for each sample to get final formation of BFO nanocrystalline. The data from XRD showing the lattice parameters a,c and the unit-cell volume V, confirm that BFO with ratio 1:12 has same crystall parameters with ratio 1:11. Ratio of Ba/Fe 1:12 and 1:11 have diffraction pattern similarly at almost each 2 θ for each samples. Ratio of Ba/Fe 1: 11.5 has the finest crystallite size 22 nm. Almost diffraction pattern peaks of Ba/Fe 1:11.5 move to the left from of Ba/Fe 1:12 then return to diffraction pattern of Ba/Fe 1:12 for Ba/Fe 1:11. SEM observations show the particle size less than 100 nm and the same shape for each sample. Ratio of Ba/Fe 1: 12 gives the highest intrinsic coercive Hc = 427.3 kA/m. The highest remanent magnetization is at ratio 1:11 with Mr = 0.170 T. BFO with mole ratio 1:11.5 has the finest grain 22 nm, good magnetic properties and the highest value of best FoM 89%.

Interface properties of bilayer structure Alq{sub 3}/Fe{sub 65}Co{sub 35}

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhen, E-mail: wangzhen@chd.edu.cn [Department of Applied Physics, Chang’an University, Xi’an 710064 (China); Xu, Chunlong; Wang, Jinguo; Chang, Qiaoli [Department of Applied Physics, Chang’an University, Xi’an 710064 (China); Zuo, Yalu; Xi, Li [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China)

2015-04-01

Highlights: • Bilayer structure of Alq{sub 3}/FeCo was fabricated in a dual ultra high vacuum chamber. • Organic layer reacts partially with the FeCo film. • Electronic injection barrier is 0.76 eV in the interface. • The induced uniaxial anisotropy appears in Alq{sub 3}/FeCo. - Abstract: The interface between the organic and magnetic electrodes is a fundamental problem in organic spintronics devices. Therefore, bilayer structure of Alq{sub 3}/FeCo was fabricated in a dual ultra high vacuum chamber. The electronic structure of Alq{sub 3}–FeCo interface has been studied by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy with Argon ion etching technique. It was found that organic layer reacts partially with the FeCo film, forming complex binding of metallic carbide and/or oxidation state in the interfacial region. Electronic injection barrier is 0.76 eV in the interface. The structural variation of the contact region is proposed to be one of the possible factors resulting in spin-injection failure. The magnetic properties of FeCo film with different thicknesses on glass substrate and Alq{sub 3} layer are also investigated. The induced uniaxial anisotropy only presents in 3 nm FeCo thickness for glass/FeCo, while it appears in 3–5 nm FeCo for Alq{sub 3}/FeCo.

Microstructure and Magnetic Properties of Fe and Fe-alloy Thin Films Epitaxially Grown on MgO(100) Substrates

Energy Technology Data Exchange (ETDEWEB)

Matsubara, Katsuki; Ohtake, Mitsuru; Futamoto, Masaaki [Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Kirino, Fumiyoshi, E-mail: matsubara@futamoto.elect.chuo-u.ac.jp [Graduate School of Fine Arts, Tokyo National University of Fine Arts and Music, 12-8 Ueno-koen, Taito-ku, Tokyo 110-8714 (Japan)

2011-07-06

Fe, Fe{sub 50}Co{sub 50}, and Fe{sub 80}Ni{sub 20} (at. %) single-crystal films with the (100){sub bcc} plane parallel to the substrate surface were prepared on MgO(100) single-crystals heated at 300 {sup 0}C by ultra high vacuum molecular beam epitaxy. The film growth mechanism, the film structure, and the magnetic properties were investigated. In-situ reflection high energy electron diffraction and X-ray diffraction analyses indicate that the strains in the films are very small though there are fairly large mismatches of -3.7{approx}-4.3% at the film/substrate interface. Cross-sectional high-resolution transmission electron microscopy shows that misfit dislocations are introduced in the film at the interface. Dislocations are also observed in the film up to around 10{approx}20 nm distance from the interface. The presence of such dislocation relieves the strain caused by the lattice mismatch. The in-plane magnetization properties of these films reflect the magnetocrystalline anisotropies of respective bulk Fe, Fe{sub 50}Co{sub 50}, and Fe{sub 80}Ni{sub 20} crystals.

Microstructure and Magnetic Properties of Fe and Fe-alloy Thin Films Epitaxially Grown on MgO(100) Substrates

International Nuclear Information System (INIS)

Matsubara, Katsuki; Ohtake, Mitsuru; Futamoto, Masaaki; Kirino, Fumiyoshi

2011-01-01

Fe, Fe 50 Co 50 , and Fe 80 Ni 20 (at. %) single-crystal films with the (100) bcc plane parallel to the substrate surface were prepared on MgO(100) single-crystals heated at 300 0 C by ultra high vacuum molecular beam epitaxy. The film growth mechanism, the film structure, and the magnetic properties were investigated. In-situ reflection high energy electron diffraction and X-ray diffraction analyses indicate that the strains in the films are very small though there are fairly large mismatches of -3.7∼-4.3% at the film/substrate interface. Cross-sectional high-resolution transmission electron microscopy shows that misfit dislocations are introduced in the film at the interface. Dislocations are also observed in the film up to around 10∼20 nm distance from the interface. The presence of such dislocation relieves the strain caused by the lattice mismatch. The in-plane magnetization properties of these films reflect the magnetocrystalline anisotropies of respective bulk Fe, Fe 50 Co 50 , and Fe 80 Ni 20 crystals.

Physicochemical characterization of Fe3O4/SiO2/Au multilayer nanostructure

International Nuclear Information System (INIS)

Khosroshahi, Mohammad E.; Ghazanfari, Lida

2012-01-01

Highlights: ► The purpose of the research was to synthesize and characterize Fe 3 O 4 /SiO 2 /Au NPs. ► Uncoated MNPs showed an Ms range of 80–100 emu g −1 for particles between 35–96 nm. ► The magnetic NPs were modified with a thin layer of silica using Stober method. ► Small gold colloids (1–3 nm) were covered the amino functionalized particle surface. ► An absorption peak of 550 nm was obtained for a gold thickness of about 35 nm. - Abstract: The purpose of this research was to synthesize and characterize gold-coated Fe 3 O 4 /SiO 2 nanoshells for biomedical applications. Magnetite nanoparticles (NPs) were prepared using co-precipitation method. Smaller particles were synthesized by decreasing the NaOH concentration, which in our case this corresponded to 35 nm using 0.9 M of NaOH at 750 rpm with a specific surface area of 41 m 2 g −1 . For uncoated Fe 3 O 4 NPs, the results showed an octahedral geometry with saturation magnetization range of 80–100 emu g −1 and coercivity of 80–120 Oe for particles between 35 and 96 nm, respectively. The magnetic NPs were modified with a thin layer of silica using Stober method. Small gold colloids (1–3 nm) were synthesized using Duff method and covered the amino functionalized particle surface. Magnetic and optical properties of gold nanoshells were assessed using Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM), UV–Vis spectrophotometer, atomic and magnetic force microscope (AFM, MFM), and transmission electron microscope (TEM). Based on the X-ray diffraction (XRD) results, three main peaks of Au (1 1 1), (2 0 0) and (2 2 0) were identified. The formation of each layer of a nanoshell is also demonstrated by Fourier transform infrared (FTIR) results. The Fe 3 O 4 /SiO 2 /Au nanostructures, with 85 nm as particle size, exhibited an absorption peak at ∼550 nm with a magnetization value of 1.3 emu g −1 with a specific surface area of 71 m 2 g −1 .

Synthesis and photocatalytic activity of mesoporous nanocrystalline Fe-doped titanium dioxide

KAUST Repository

Qamar, Mohd

2014-07-01

Synthesis of mesoporous nanocrystalline iron-doped titania following the sol-gel method is presented in this work. Samples with various molar ratios (0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10 and 20%) of Fe to Ti were prepared. The particle size was found to be in the range of ∼12 nm while mesopores were approximately near to ∼5.5 nm. The effect of Fe as doping element on titania properties, such as crystallite size, surface area, pore size, pore volume and d-spacing was investigated. Moreover, distribution of Fe in TiO2 matrix was determined by elemental mapping whereas change in absorption properties was evaluated by diffuse reflectance spectroscopy. It was observed that as the Fe content was increased, a partial phase transformation from anatase to rutile and pseudorutile took place. Effect of ultraviolet, ultraviolet-visible and visible radiations on the photocatalytic activity of these catalysts was studied by removal of Methyl Orange as model pollutant. As results, it was found that the photocatalytic activity of such catalysts depends strongly on Fe amount and type of radiation. © 2013 Elsevier B.V.

Sediment Dynamics Affecting the Threatened Santa Ana Sucker in the Highly-modified Santa Ana River and Inset Channel, Southern California, USA

Science.gov (United States)

Minear, J. T.; Wright, S. A.

2015-12-01

In this study, we investigate the sediment dynamics of the low-flow channel of the Santa Ana River that is formed by wastewater discharges and contains some of the last remaining habitat of the Santa Ana Sucker (Catostomus santaanae). The Santa Ana River is a highly-modified river draining the San Bernardino Mountains and Inland Empire metropolitan area east of Los Angeles. Home to over 4 million people, the watershed provides habitat for the federally-threatened Santa Ana Sucker, which presently reside within the mainstem Santa Ana River in a reach supported by year-round constant discharges from water treatment plants. The nearly constant low-flow wastewater discharges and infrequent runoff events create a small, approximately 8 m wide, inset channel within the approximately 300 m wide mainstem channel that is typically dry except for large flood flows. The sediment dynamics within the inset channel are characterized by constantly evolving bed substrate and sediment transport rates, and occasional channel avulsions. The sediment dynamics have large influence on the Sucker, which rely on coarse-substrate (gravel and cobble) for their food production. In WY 2013 through the present, we investigated the sediment dynamics of the inset channel using repeat bathymetric and substrate surveys, bedload sampling, and discharge measurements. We found two distinct phases of the inset channel behavior: 1. 'Reset' flows, where sediment-laden mainstem discharges from upstream runoff events result in sand deposition in the inset channel or avulse the inset channel onto previously dry riverbed; and 2. 'Winnowing' flows, whereby the sand within the inset channel is removed by clear-water low flows from the wastewater treatment plant discharges. Thus, in contrast to many regulated rivers where high flows are required to flush fine sediments from the bed (for example, downstream from dams), in the Santa Ana River the low flows from wastewater treatment plants serve as the flushing

Composition dependence of crystallization temperature and magnetic property of NdFeB thin films

Energy Technology Data Exchange (ETDEWEB)

Khoa, T.V. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi (Viet Nam); Ha, N.D. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Hong, S.M. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Jin, H.M. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Kim, G.W. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Hien, T.D. [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi (Viet Nam); Tai, L.T. [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi (Viet Nam); Duong, N.P. [International Training Institute for Materials Science (ITIMS), Hanoi University of Technology, 1 Dai Co Viet, Hanoi (Viet Nam); Lee, K.E. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Kim, C.G. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of); Kim, C.O. [Research Center for Advanced Magnetic Materials (ReCAMM), Chungnam National University, Daejon, 305-764 (Korea, Republic of)]. E-mail: magkim@cnu.ac.kr

2006-09-15

Si(100)/Mo(30nm)/Nd{sub x}Fe{sub 92-x}B{sub 8}(800nm)/Mo(30nm) (x=14, 20, 30) films are prepared by RF magnetron sputtering at room temperature. As-deposited films are amorphous materials. The crystallization temperature of the Nd{sub 2}Fe{sub 14}B phase decreases from 575deg. C to 500deg. C with increase of x from 14 to 20-30. The optimum annealing temperature with 30min annealing time is 650 deg. C, 625 deg. C and 600 deg. C for x=14, 20 and 30, respectively, and the x=20 film has the largest energy product of 100118MG.

The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar; Skoko, Zeljko; Popovic, Stanko

2006-01-01

The influence of Zn-dopant on the precipitation of α-FeOOH in highly alkaline media was monitored by X-ray diffraction (XRD), 57 Fe Moessbauer and Fourier transform infrared (FT-IR) spectroscopies and field emission scanning electron microscopy (FE SEM). Acicular and monodisperse α-FeOOH particles were precipitated at a very high pH by adding a tetramethylammonium hydroxide solution to an aqueous solution of FeCl 3 . The XRD analysis of the samples precipitated in the presence of Zn 2+ ions showed the formation of solid solutions of α-(Fe, Zn)OOH up to a concentration ratio r = [Zn]/([Zn] + [Fe]) = 0.0909. ZnFe 2 O 4 was additionally formed in the precipitate for r = 0.1111, whereas the three phases α-FeOOH, α-Fe 2 O 3 and ZnFe 2 O 4 were formed for r 0.1304. In the corresponding FT-IR spectra, the Fe-OH and Fe-O stretching bands were sensitive to the Zn 2+ substitution, whereas the Fe-OH bending bands of α-FeOOH at 892 and 796 cm -1 were almost insensitive. The Moessbauer spectra showed a high sensitivity to the formation of α-(Fe, Zn)OOH solid solutions which were monitored on the basis of a decrease in B hf values in dependence on Zn-doping. A strictly linear decrease in B hf for α-FeOOH doped with Zn 2+ ions was measured up to r = 0.0291, whereas for r = 0.0476 and higher there was a deviation from linearity. The presence of α-(Fe, Zn)OOH, α-Fe 2 O 3 and ZnFe 2 O 4 phases in the samples was determined quantitatively by Moessbauer spectroscopy. Likewise, Moessbauer spectroscopy did not show any formation of the solid solutions of α-Fe 2 O 3 with Zn 2+ ions. FE SEM showed a strong effect of Zn-doping on the elongation of acicular α-FeOOH particles (∼500-700 nm in length) up to r = 0.1111. For r = 0.1304 the sizes of ZnFe 2 O 4 particles were around 30-50 nm, and those of α-Fe 2 O 3 particles were around 500 nm, whereas a relatively small number of very elongated α-(Fe, Zn)OOH particles was observed. A possible mechanism of the formation of α-(Fe

New method for simultaneous determination of Fe(II) and Fe(III) in water using flow injection technique

International Nuclear Information System (INIS)

Kozak, J.; Gutowski, J.; Kozak, M.; Wieczorek, M.; Koscielniak, P.

2010-01-01

The method exploits the possibilities of flow injection gradient titration in a system of reversed flow with spectrophotometric detection. In the developed approach a small amount of titrant (EDTA) is injected into a stream of sample containing a mixture of indicators (sulfosalicylic acid and 1,10-phenanthroline). In acid environment sulfosalicylic acid forms a complex with Fe(III), whereas 1,10-phenanthroline forms a complex with Fe(II). Measurements are performed at wavelength λ = 530 nm when radiation is absorbed by both complexes. After injection EDTA replaces sulfosalicylic acid and forms with Fe(III) more stable colourless complex. As a result, a characteristic 'cut off' peak is registered with a width corresponding to the Fe(III) concentration and with a height corresponding to the Fe(II) concentration. Calibration was performed by titration of four two-component standard solutions of the Fe(II)/Fe(III) concentrations established in accordance with 2 2 factorial plan. The method was tested with the use of synthetic samples and then it was applied to the analysis of water samples taken from artesian wells. Under optimized experimental conditions Fe(II) and Fe(III) were determined with precision less than 0.8 and 2.5% (RSD) and accuracy less than 3.2 and 5.1% (relative error) within the concentration ranges of 0.1-3.0 and 0.9-3.5 mg L -1 of both analytes, respectively.

Structure and magnetic properties of NdFeB thin films with Cr, Mo, Nb, Ta, Ti, and V buffer layers

International Nuclear Information System (INIS)

Jiang, H.; O'Shea, M.J.

2000-01-01

Layers of NdFeB of the form A(20 nm)/NdFeB(d nm)/A(20 nm) where A represents Cr, Mo, Nb, Ta, Ti, V were prepared on a silicon substrate by magnetron sputtering. The purpose is to determine how (i) the chosen buffer layer and (ii) NdFeB layer thickness d (especially d 2 Fe 14 B with no preferred crystalline orientation. Our highest coercivities occur for buffer layer elements from row five of the periodic table, 20 kOe (1600 kA/m) in a Nb buffered sample with d of 180 nm and 17 kOe (1350 kA/m) in a Mo buffered sample with d of 180 nm. Buffer layers from row four (Ti, V, and Cr) and row six (Ta) all give lower coercivities. Our largest energy product, 10.3 MG-Oe (82 kJ/m 3 ), is obtained for the Mo buffered sample. Average Nd 2 Fe 14 B crystallite size for this sample is 27 nm. Only the Cr and Ti buffered films show a large coercivity (≥2 kOe) for d of 54 nm with the Cr films showing the highest coercivity, 2.7 kOe (215 kA/m). In films subjected to a rapid thermal anneal (anneal time 30 s) we find that both the coercivity and energy product are larger than in samples subjected to a 20 min anneal. In our Nb buffered systems we obtain coercivities as high as 26.3 kOe (2090 kA/m) after a rapid thermal anneal

Nanosized catalysts based on Fe oxide for combustion of n-hexane

International Nuclear Information System (INIS)

Picasso, Gino; Hermoza, Emilia; Lopez, Alcides; Gomez, Gemma; Pina, Maria Pilar; Herguido, Javier

2009-01-01

In this work, nanosized catalysts on Fe oxide have been prepared for total combustion on n-hexane (2000 ppmV). The synthesis of Fe oxide have been performed following sol-gel procedure starting from precursors based on nitrate salts. According to XRD analysis, nanoparticles formed α-hematite and the average particle size estimated by TEM was 9 nm with formation of agglomerations of 140 nm. Moreover, different clays pillared with Al (Al-PILC), Ti (Ti-PILC) and Fe (Fe-PILC) have been synthesized. Some samples based on Fe-Mn equimolar mixed supported on Al-PILC (FeMn/Al-PILC) and on Ti-PILC (FeMn/Ti-PILC) have been prepared in order to study the cooperative effect of Mn. Experimental conditions of calcination were adjusted in order to obtain samples with high thermal stability. XRD analysis of pillared samples revealed the formation of stable pillars, except for Fe-PILC which described a delaminated structure. As a consequence of pillaring, an enhancement of total surface area compared to starting clay material is observed. Concerning surface area, the decreasing order series of pillared material was: Ti-PILC > Fe-PILC > Al-PILC. Depression of total surface area decreasing of basal spacing d 001 with no modification of basal structure of starting natural clay have been observed due to the incorporation of Fe-Mn active phase into the structures of Ti-PILC and Al-PILC. The Fe-Mn mixed phase supported over pillared material exhibited higher catalytic activity than the Fe-PILC sample, which was attributed to the cooperative effect of Mn. This effect could be associated with redox properties of Mn and improving of surface oxygen mobility. Delaminated structure and strong interaction of Fe with clay porous network into the Fe-PILC sample could be the reason of lower activities. However, higher performances were observed in the case of Fe oxide nanoparticles prepared with surfactant agent over bentonite, due to a lesser extent of Fe-porous structure interaction presented in

The effect of the MgO buffer layer thickness on magnetic anisotropy in MgO/Fe/Cr/MgO buffer/MgO(001)

Energy Technology Data Exchange (ETDEWEB)

Kozioł-Rachwał, Anna, E-mail: a.koziolrachwal@aist.go.jp [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Nozaki, Takayuki; Zayets, Vadym; Kubota, Hitoshi; Fukushima, Akio; Yuasa, Shinji [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Suzuki, Yoshishige [National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

2016-08-28

The relationship between the magnetic properties and MgO buffer layer thickness d was studied in epitaxial MgO/Fe(t)/Cr/MgO(d) layers grown on MgO(001) substrate in which the Fe thickness t ranged from 0.4 nm to 1.1 nm. For 0.4 nm ≤ t ≤ 0.7 nm, a non-monotonic coercivity dependence on the MgO buffer thickness was shown by perpendicular magneto-optic Kerr effect magnetometry. For thicker Fe films, an increase in the buffer layer thickness resulted in a spin reorientation transition from perpendicular to the in-plane magnetization direction. Possible origins of these unusual behaviors were discussed in terms of the suppression of carbon contamination at the Fe surface and changes in the magnetoelastic anisotropy in the system. These results illustrate a method to control magnetic anisotropy in MgO/Fe/Cr/MgO(d) via an appropriate choice of MgO buffer layer thickness d.

Hydrothermal synthesis, off-axis electron holography and magnetic properties of Fe3O4 nanoparticles

DEFF Research Database (Denmark)

Almeida, Trevor P.; Muxworthy, Adrian R.; Williams, Wyn

2014-01-01

The hydrothermal synthesis of Fe3O4 nanoparticles (NPs) (<50 nm) from mixed FeCl3 / FeCl2 precursor solution at pH ~ 12 has been confirmed using complementary characterisation techniques of transmission electron microscopy and X-ray diffractometry. Off-axis electron holography allowed for visuali......The hydrothermal synthesis of Fe3O4 nanoparticles (NPs) (holography allowed...

High rectification ratios of Fe-porphyrin molecules on Au facets

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaoyu; Wang, Gwo-Ching [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, NY 12180 (United States); Lewis, Kim M., E-mail: lewisk2@rpi.edu [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110, 8th Street, Troy, NY 12180 (United States)

2012-09-14

We report room temperature measurements of current vs. voltage (I-V) from self-assembled Fe porphyrin [Fe(III) 5,15-di[4-(s-acetylthio)phenyl]-10,20-diphenyl porphine] molecular layers formed on annealed gold crystal facets on glass substrates. I-V curves were measured using an atomic force microscope with a conductive platinum tip. We observed a rectifier effect that shows asymmetric I-V curves from a monolayer of molecules. The majority rectification ratios at {+-}1 V obtained from hundreds of I-V lie in between 20 and 200, with the highest up to 9000. This is in contrast to the symmetric I-V curves measured from a few nm thick multilayer molecular islands. We contribute the observed rectification in ultrathin FeP molecular layers from asymmetric Schottky barriers that result from molecules in different bonding strengths to electrodes of gold and platinum. -- Highlights: Black-Right-Pointing-Pointer FeP molecular layers or islands of different thickness were self-assembled on Au. Black-Right-Pointing-Pointer High rectification ratios up to 9000 observed in sub-nm thick FeP molecular layers. Black-Right-Pointing-Pointer Measured current vs. voltage using a conductive AFM tip as one electrode. Black-Right-Pointing-Pointer Observed rectification of symmetric molecules using two different electrodes.

Room temperature ferromagnetism in Fe-doped CuO nanoparticles.

Science.gov (United States)

Layek, Samar; Verma, H C

2013-03-01

The pure and Fe-doped CuO nanoparticles of the series Cu(1-x)Fe(x)O (x = 0.00, 0.02, 0.04, 0.06 and 0.08) were successfully prepared by a simple low temperature sol-gel method using metal nitrates and citric acid. Rietveld refinement of the X-ray diffraction data showed that all the samples were single phase crystallized in monoclinic structure of space group C2/c with average crystallite size of about 25 nm and unit cell volume decreases with increasing iron doping concentration. TEM micrograph showed nearly spherical shaped agglomerated particles of 4% Fe-doped CuO with average diameter 26 nm. Pure CuO showed weak ferromagnetic behavior at room temperature with coercive field of 67 Oe. The ferromagnetic properties were greatly enhanced with Fe-doping in the CuO matrix. All the doped samples showed ferromagnetism at room temperature with a noticeable coercive field. Saturation magnetization increases with increasing Fe-doping, becomes highest for 4% doping then decreases for further doping which confirms that the ferromagnetism in these nanoparticles are intrinsic and are not resulting from any impurity phases. The ZFC and FC branches of the temperature dependent magnetization (measured in the range of 10-350 K by SQUID magnetometer) look like typical ferromagnetic nanoparticles and indicates that the ferromagnetic Curie temperature is above 350 K.

Violet emission from Fe doped ZnO nanoparticles synthesized by precipitation method

Energy Technology Data Exchange (ETDEWEB)

Kanchana, S., E-mail: skanchana09@gmail.com [PG & Research Department of Physics, Urumu Dhanalaksmi College, Tiruchirapalli 620019 (India); Chithra, M. Jay [Nanomaterials Research Laboratory, Department of Physics, Government Arts College, Karur 639005 (India); Ernest, Suhashini [PG & Research Department of Physics, Urumu Dhanalaksmi College, Tiruchirapalli 620019 (India); Pushpanathan, K. [Nanomaterials Research Laboratory, Department of Physics, Government Arts College, Karur 639005 (India)

2016-08-15

In this article we have reported the synthesis of Fe doped zinc oxide nanoparticles by the chemical precipitation method. The structural, compositional and optical properties have been examined by powder X-ray diffractometer, scanning electron microscope, transmission electron microscope, ultraviolet–visible and spectrophotometer. X-ray diffraction analysis confirmed the crystallites are in nanometer size and the sample contains polycrystals with hexagonal wurtzite structure. The average crystallite size has been found to increase from 25 nm to 36 nm with increase in Fe concentration. Scanning electron microscope result also confirmed the nanosize of the particles. Ultraviolet–visible spectrum of Fe doped zinc oxide shows a red shift with respect to undoped zinc oxide. The band gap of the samples was calculated from ultraviolet–visible spectrum and it is narrow from 3.30 eV to 3.23 eV with increasing Fe dopant upto 6%. The stretching bonds in Zn– Fe–O have been observed in FTIR spectra.

Quasicrystalline and crystalline phases in Al65Cu20(Fe, Cr)15 alloys

International Nuclear Information System (INIS)

Liu, W.; Koester, U.; Mueller, F.; Rosenberg, M.

1992-01-01

Two types of icosahedral quasicrystals are observed in Al 65 Cu 20 Fe 15-x Cr x (0 ≤ x ≤ 15) alloys, the face-centred AlCuFe-type icosahedral phase with dissoluted Cr and the primitive AlCuCr-type icosahedral phase with dissoluted Fe. In the vicinity of Al 65 Cu 20 Fe 8 Cr 7 a stable decagonal phase (a=0.45 nm and c=1.23 nm) forms competitively with the icosahedral quasicrystals. All these three quasicrystalline phases can be regarded as Hume-Rothery phases stabilized by the energy band factor. The density is measured to be 4.57, 4.44, and 4.11 g/cm 3 for the icosahedral Al 65 Cu 20 Fe 15 , the decagonal Al 65 Cu 20 Fe 8 Cr 7 , and the icosahedral Al 65 Cu 20 Cr 15 alloys, respectively. Depending on the composition in the range between Al 65 Cu 20 Fe 8 Cr 7 and Al 65 Cu 20 Cr 15 , several crystalline phases are observed during the transormation of the AlCuCr-type icosahedral phase: the 1/1-3/2-type orthorhombic (o) and the 1/0-3/2-type tetragonal (t) approximants of the decagonal phase, a hexagonal (h) phase, as well as a long-range vacancy ordered τ 3 -phase derived from a CsCl-type structure with a=0.2923 nm. The structures of all the crystalline phases are closely related to those of the icosahedral (i) and decagonal (d) quasicrystals, which leads to a definite orientation relationship as follows: i5 parallel d10 parallel o[100] parallel t[100] parallel h[001] parallel τ 3 [110]. (orig.)

Synthesis and characterization of Fe-doped TiO2 photocatalyst by the sol–gel method

International Nuclear Information System (INIS)

Luu, Cam Loc; Ho, Si Thoang; Nguyen, Quoc Tuan

2010-01-01

Thin layers of pure TiO 2 and TiO 2 doped by different amounts of Fe 2 O 3 have been prepared by the sol–gel method with tetraisopropyl orthotitanate and Fe(NO 3 ) 3 . Physico-chemical properties of catalysts were characterized by BET Adsorption, x-ray Diffraction (XRD), FE-SEM, as well as Raman and UV-Vis spectroscopy. The photocatalytic activity of the obtained materials was investigated in the reaction of complete oxidation of p-xylene in gas phase under the radiation of UV (λ=365 nm) and LED (λ=470 nm) lamps. It has been found that the particle size of all samples was distributed in the range 20–30 nm. The content of the rutile phase in Fe-doped TiO 2 samples varied in the range 6.8 to 41.8% depending on the Fe content. Iron oxide doped into TiO 2 enables the photon absorbing zone of TiO 2 to extend from UV towards visible waves as well as to reduce its band gap energy from 3.2 to 2.67 eV. Photocatalytic activities of the TiO 2 samples modified by Fe 3+ have been found to be higher than those of pure TiO 2 by about 2.5 times

Early Neogene unroofing of the Sierra Nevada de Santa Marta along the Bucaramanga -Santa Marta Fault

Science.gov (United States)

Piraquive Bermúdez, Alejandro; Pinzón, Edna; Bernet, Matthias; Kammer, Andreas; Von Quadt, Albrecht; Sarmiento, Gustavo

2016-04-01

Plate interaction between Caribbean and Nazca plates with Southamerica gave rise to an intricate pattern of tectonic blocks in the Northandean realm. Among these microblocks the Sierra Nevada de Santa Marta (SNSM) represents a fault-bounded triangular massif composed of a representative crustal section of the Northandean margin, in which a Precambrian to Late Paleozoic metamorphic belt is overlain by a Triassic to Jurassic magmatic arc and collateral volcanic suites. Its western border fault belongs to the composite Bucaramanga - Santa Marta fault with a combined left lateral-normal displacement. SE of Santa Marta it exposes remnants of an Oligocene marginal basin, which attests to a first Cenoizoic activation of this crustal-scale lineament. The basin fill consists of a sequence of coarse-grained cobble-pebble conglomerates > 1000 m thick that unconformably overlay the Triassic-Jurassic magmatic arc. Its lower sequence is composed of interbedded siltstones; topwards the sequence becomes dominated by coarser fractions. These sedimentary sequences yields valuable information about exhumation and coeval sedimentation processes that affected the massif's western border since the Upper Eocene. In order to analyse uplifting processes associated with tectonics during early Neogene we performed detrital zircon U-Pb geochronology, detrital thermochronology of zircon and apatites coupled with the description of a stratigraphic section and its facies composition. We compared samples from the Aracataca basin with analog sequences found at an equivalent basin at the Oca Fault at the northern margin of the SNSM. Our results show that sediments of both basins were sourced from Precambrian gneisses, along with Mesozoic acid to intermediate plutons; sedimentation started in the Upper Eocene-Oligocene according to palynomorphs, subsequently in the Upper Oligocene a completion of Jurassic to Cretaceous sources was followed by an increase of Precambrian input that became the dominant

Magneto-optical properties of α-Fe2O3@ZnO nanocomposites prepared by the high energy ball-milling technique

Science.gov (United States)

Chaudhury, Chandana Roy; Roychowdhury, Anirban; Das, Anusree; Das, Dipankar

2016-05-01

Magnetic-fluorescent nanocomposites (NCs) with 10 wt% of α-Fe2O3 in ZnO have been prepared by the high energy ball-milling. The crystallite sizes of α-Fe2O3 and ZnO in the NCs are found to vary from 65 nm to 20 nm and 47 nm to 15 nm respectively as milling time is increased from 2 to 30 h. XRD analysis confirms presence of α-Fe2O3 and ZnO in pure form in all the NCs. UV-vis study of the NCs shows a continuous blue-shift of the absorption peak and a steady increase of band gap of ZnO with increasing milling duration that are assigned to decreasing particle size of ZnO in the NCs. Photoluminescence (PL) spectra of the NCs reveal three weak emission bands in the visible region at 421, 445 and 485 nm along with the strong near band edge emission at 391 nm. These weak emission bands are attributed to different defect - related energy levels e.g. Zn-vacancy, Zn interstitial and oxygen vacancy. Dc and ac magnetization measurements show presence of weakly interacting superparamagnetic (SPM) α-Fe2O3 particles in the NCs. 57Fe-Mössbauer study confirms presence of SPM hematite in the sample milled for 30 h. Positron annihilation lifetime measurements indicate presence of cation vacancies in ZnO nanostructures confirming results of PL studies.

Simulation of SANS signal due to radiation damage in Fe

International Nuclear Information System (INIS)

Yu, G.; Schaublin, R.; Spatig, P.; Fikar, J.; Baluc, N.

2007-01-01

Full text of publication follows: A wide number of irradiation-induced defects in Fe-base materials (e.g. RAFM steels) have sizes in the range about 0.5 to 1 nm, which are expected to contribute to the irradiation-induced hardening and/or embrittlement phenomena. These defects are at the limit in spatial resolution of transmission electron microscopy (TEM), but they can be investigated using the small angle neutron scattering (SANS) technique, at least in terms of number density and size distribution. Determination of the type of defects (small dislocation loops, interstitials or vacancy clusters, precipitates and cavities, like voids or helium bubbles) is not straightforward. In order to analyze the type of nanometer-sized irradiation-induced defects in Fe-base materials Molecular Dynamics (MD) simulations of various distributions of different types irradiation-induced defects have been performed. The defects investigated consisted in dislocation loops with sizes of 0.5, 1.0 and 2.0 nm and 1/2 a 0 , 1/2 a 0 and a 0 Burgers vectors, cavities, like voids and helium bubbles, with sizes of 0.5, 1.0 and 2.0 nm, MD simulations of atomic displacement cascades were performed using MD samples with a size of 18 x 18 x 18 nm 3 at 10, 300 and 523 K, for PKA energies of 1, 3, 7 and 10 keV. Simulation of the corresponding nuclear SANS signal was performed using the Electron Microscopy Software (EMS) code that was originally designed to simulate TEM images and diffraction patterns and that was modified to simulate the SANS signal. Results of such simulations in pure Fe have been compared to experimental SANS measurements and TEM observations of irradiation-induced defects in Fe-base materials. (authors)

Selective growth of vertically aligned Fe-filled carbon nanotubes on oxidized silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Moench, I; Kozhuharova-Koseva, R; Ruemmeli, M; Elefant, D; Gemming, T; Kaltofen, R; Leonhardt, A; Schaefer, T; Buechner, B [Leibniz Institute of Solid State and Materials Research Dresden (IFW Dresden), Helmholtzstr. 20, D-01069 Dresden (Germany)

2007-04-15

Vertically aligned Fe-filled multi-wall carbon nanotubes (MWNTs) have been grown selectively on the SiO{sub 2} surfaces of patterned amorphous carbon (a-C)/SiO{sub 2}/Si substrates. Their morphology, structure and magnetic properties have been studied. The a-C patterns were prepared using conventional lithography processes combined with a sputter-deposition of a-C (thickness of 100 nm). The aligned Fe-filled MWNTs were produced by pyrolysis of ferrocene in a CVD reactor with a two zone furnace system and have high filling yield. The encapsulated Fe nanowires grown on the SiO{sub 2} structures of the patterned a-C/SiO{sub 2}/Si substrates have diameters of 10-20 nm and can reach a few micrometers in length. The described method enables the preparation of complex architectures of Fe-filled MWNTs and may be used for future applications based on filled nanotubes.

Multiobjective Optimal Control Methodology for the Analysis of Certain Sociodynamic Problems

Science.gov (United States)

2009-03-01

but less expensive in both time and memory. 137 References [1] R. Albert and A-L Barabasi. Statistical mechanics of complex networks. Reviews of Modern...Review, E(51):4282–4286, 1995. [24] D. Helbing, P. Molnar, and F. Schweitzer . Computer simulation of pedestrian dynamics and trail formation. May 1998...Patterson AFB, OH, 2001. [49] F. Schweitzer . Brownian Agents and Active Particles. Springer, Santa Fe, NM, 2003. [50] P. Sen. Complexities of social

The anisotropy field of FePt L10 nanoparticles controlled by very thin Pt layer

International Nuclear Information System (INIS)

Okamoto, Satoshi; Kitakami, Osamu; Kikuchi, Nobuaki; Miyazaki, Takamichi; Shimada, Yutaka; Chiang, Te-Hsuan

2004-01-01

We have prepared epitaxial FePt L1 0 (001) nanoparticles covered with Pt [d Pt nm]/Ag[(4-d Pt ) nm] overlayers. The particles are oblate spheroids approximately 10 nm in diameter and 2 nm in height. The anisotropy field H k at 0 K, which is evaluated from the temperature dependences of coercivity H c , decreases from 90 to 60 kOe on increasing the Pt thickness from d Pt 0 to 1.5 nm, while the energy barrier at zero field remains unchanged. The significant reduction of H k due to the presence of the adjacent Pt layer can be attributed to an enhanced magnetic moment caused by the ferromagnetic polarization of Pt atoms at the interface. This finding suggests an effective method of controlling the switching field of FePt L1 0 nanoparticles

Evaluation of Antioxidant and Cytotoxicity Activities of Copper Ferrite (CuFe2O4 and Zinc Ferrite (ZnFe2O4 Nanoparticles Synthesized by Sol-Gel Self-Combustion Method

Directory of Open Access Journals (Sweden)

Samikannu Kanagesan

2016-08-01

Full Text Available Spinel copper ferrite (CuFe2O4 and zinc ferrite (ZnFe2O4 nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe2O4 and 68 nm for ZnFe2O4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug−1 for copper ferrite (50.63 Am2/Kg and 28.8 Am2/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH free radicals. ZnFe2O4 and CuFe2O4 nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL of ZnFe2O4 and CuFe2O4 with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

Streamflow in the upper Santa Cruz River basin, Santa Cruz and Pima Counties, Arizona

Science.gov (United States)

Condes de la Torre, Alberto

1970-01-01

Streamflow records obtained in the upper Santa Cruz River basin of southern Arizona, United States, and northern Sonora, Mexico, have been analyzed to aid in the appraisal of the surface-water resources of the area. Records are available for 15 sites, and the length of record ranges from 60 years for the gaging station on the Santa .Cruz River at Tucson to 6 years for Pantano Wash near Vail. The analysis provides information on flow duration, low-flow frequency magnitude, flood-volume frequency and magnitude, and storage requirements to maintain selected draft rates. Flood-peak information collected from the gaging stations has been projected on a regional basis from which estimates of flood magnitude and frequency may be made for any site in the basin. Most streams in the 3,503-square-mile basin are ephemeral. Ground water sustains low flows only at Santa Cruz River near Nogales, Sonoita Creek near Patagonia, and Pantano Wash near Vail. Elsewhere, flow occurs only in direct response to precipitation. The median number of days per year in which there is no flow ranges from 4 at Sonoita Creek near Patagonia to 335 at Rillito Creek near Tomson. The streamflow is extremely variable from year to year, and annual flows have a coefficient of variation close to or exceeding unity at most stations. Although the amount of flow in the basin is small most of the time, the area is subject to floods. Most floods result from high-intensity precipitation caused by thunderstorms during the period ,July to September. Occasionally, when snowfall at the lower altitudes is followed by rain, winter floods produce large volumes of flow.

MnFe2O4/CdSe magneto-fluorescent nanocomposite for possible biomedical applications

Science.gov (United States)

Chandunika, R. K.; Vijayaraghavan, R.; Sahu, Niroj Kumar

2018-04-01

Acombined superparamagnetic and fluorescent MnFe2O4/CdSe multifunctional nanocompositehas been prepared by suitable surface functionalizationswith citric acid, polyethyleneimine(PEI) and thioglycolic acid (ThA).and the samples were characterized by XRD, FT-IR, TEM, Zeta Potential, VSM, UV-Vis and PL spectroscopy. MnFe2O4 crystalizes with average size of 38.6 nm whereas CdSe with average size of 2.03 nm. In composite, the CdSe quantum dots (QD) are homogeneously distributed in the matrix of porous MnFe2O4 nanoparticles. Thenanocomposites are well dispersed in aqueous solvent and possess significant magnetic and luminescence properties which may be utilised for magnetic resonance imaging and luminescence tagging of biomolecules.

Prospects of Fe/MCM-41 as a Catalyst for Hydrocarbon Synthesis

International Nuclear Information System (INIS)

Cagnoli, Maria V.; Gallegos, Norma G.; Bengoa, Jose F.; Alvarez, Ana M.; Marchetti, Sergio G.; Moreno, Sergio M. J.; Roig, Anna; Mercader, Roberto C.

2005-01-01

We report the synthesis of cylindrical nanoparticles of metallic Fe entirely included in MCM-41 pores. Their dimensions are approx.3 nm diameter and approx. 3.8 nm length. We show that a coherent analysis of the results yielded by the various techniques is essential to obtain a catalyst supported on an MCM-41 matrix of ≅ 3 nm average pore diameter, which is active and selective toward olefins. The solids were characterized by low-angle x-ray diffraction, high-resolution transmission electron microscopy, high-resolution scanning transmission electron microscopy equipped with a high-angle annular dark-field, CO chemisorption, volumetric oxidation, and Moessbauer spectroscopy (in controlled atmosphere for the reduced catalysts). Catalytic results in the Fischer-Tropsch synthesis, as well as some unexpected results --like the inhomogeneous pore filling and discontinuous Fe particles-- are also discussed

Effect of heat treatment on interface driven magnetic properties of CoFe films

Energy Technology Data Exchange (ETDEWEB)

Singh, Akhilesh Kr., E-mail: drakhintu@gmail.com; Hsu, Jen-Hwa

2017-06-15

Highlights: • Ta underlayer and cap layer dependent anisotropy nature in thin CoFe films. • Thin Ta layer induces the magnetization component along normal to the film plane. • Heat treatment and Ta layers driven surface morphology, roughness and grain size. • Roughness reduces more than an order of magnitude with 2 nm Ta cap layer. • H{sub C}, domain patterns and domain size depend on Ta layers and heat treatment. - Abstract: We report systematic studies on non-magnetic Ta underlayer and cap layer driven microstructural and magnetic properties at a wide temperature range for CoFe films. All the films were grown at room temperature and post annealed at different annealing temperatures (T{sub A} = 200 °C, 250 °C, 300 °C, 350 °C, 400 °C and 450 °C). The in-plane magnetic hysteresis (M–H) loops of 10 nm thick CoFe single layer films, grown directly on thermally oxidized Si substrate, exhibit anisotropic nature for T{sub A} above 250 °C. However, the CoFe (10 nm) films grown on the 5 nm thick Ta underlayer show reduced anisotropy. Moreover, with underlayer and cap layers (2 nm) the anisotropy is disappeared. The in-plane coercivity (H{sub C}) shows a strong variation with T{sub A}, underlayer and cap layers. H{sub C} increases significantly with Ta underlayer and cap layers. The out of plane M–H loops exhibit increase in the remanence magnetization and squareness with both Ta underlayer and cap layers due to transition of in-plane magnetization component to the out of plane direction. The atomic force microscopic observations revealed that grain/particle size and shape depend strongly on T{sub A} and Ta layers. Moreover, a large reduction in the surface roughness is observed with the Ta cap layer. The magnetic domain patterns depend on the T{sub A}, and Ta layers. However, for Ta/CoFe/Ta films no clear domains were observed for all the T{sub A}. Hence, the Ta cap layers not only protect the CoFe magnetic layer against the heat treatment, but also

Effect of heat treatment on interface driven magnetic properties of CoFe films

International Nuclear Information System (INIS)

Singh, Akhilesh Kr.; Hsu, Jen-Hwa

2017-01-01

Highlights: • Ta underlayer and cap layer dependent anisotropy nature in thin CoFe films. • Thin Ta layer induces the magnetization component along normal to the film plane. • Heat treatment and Ta layers driven surface morphology, roughness and grain size. • Roughness reduces more than an order of magnitude with 2 nm Ta cap layer. • H C , domain patterns and domain size depend on Ta layers and heat treatment. - Abstract: We report systematic studies on non-magnetic Ta underlayer and cap layer driven microstructural and magnetic properties at a wide temperature range for CoFe films. All the films were grown at room temperature and post annealed at different annealing temperatures (T A = 200 °C, 250 °C, 300 °C, 350 °C, 400 °C and 450 °C). The in-plane magnetic hysteresis (M–H) loops of 10 nm thick CoFe single layer films, grown directly on thermally oxidized Si substrate, exhibit anisotropic nature for T A above 250 °C. However, the CoFe (10 nm) films grown on the 5 nm thick Ta underlayer show reduced anisotropy. Moreover, with underlayer and cap layers (2 nm) the anisotropy is disappeared. The in-plane coercivity (H C ) shows a strong variation with T A , underlayer and cap layers. H C increases significantly with Ta underlayer and cap layers. The out of plane M–H loops exhibit increase in the remanence magnetization and squareness with both Ta underlayer and cap layers due to transition of in-plane magnetization component to the out of plane direction. The atomic force microscopic observations revealed that grain/particle size and shape depend strongly on T A and Ta layers. Moreover, a large reduction in the surface roughness is observed with the Ta cap layer. The magnetic domain patterns depend on the T A , and Ta layers. However, for Ta/CoFe/Ta films no clear domains were observed for all the T A . Hence, the Ta cap layers not only protect the CoFe magnetic layer against the heat treatment, but also show a smooth surface at a wide

Annealing-induced Fe oxide nanostructures on GaAs

OpenAIRE

Lu, Y X; Ahmad, E; Xu, Y B; Thompson, S M

2005-01-01

We report the evolution of Fe oxide nanostructures on GaAs(100) upon pre- and post-growth annealing conditions. GaAs nanoscale pyramids were formed on the GaAs surface due to wet etching and thermal annealing. An 8.0-nm epitaxial Fe film was grown, oxidized, and annealed using a gradient temperature method. During the process the nanostripes were formed, and the evolution has been demonstrated using transmission and reflection high energy electron diffraction, and scanning electron microscopy...

Synthesis and characterization of bracelet-like magnetic nanorings consisting of Ag-Fe3O4 bi-component nanoparticles.

Science.gov (United States)

Zhou, Shuai; Chen, Qianwang

2011-09-14

Stable bracelet-like magnetic nanorings, formed by Ag-Fe(3)O(4) nanoparticles with an average size around 40 nm, have been successfully prepared in large scale by means of reducing Ag(+) and Fe(3+) simultaneously under mild conditions. In the reaction, tiny grains of silver are used as seeds to prompt small Fe(3)O(4) nanoparticles to grow larger, which is essential to enhance the magnetic dipole-dipole interactions, while only superparamagnetic Fe(3)O(4) nanoparticles (about 10 nm in size) can be obtained in the absence of Ag seeds. The XRD, TEM, SAED and the EDS line scan data reveal that these nanoparticles are in the core-shell structure. These magnetic Ag-Fe(3)O(4) nanoparticles assembled into nanorings by magnetic dipole-dipole interactions with a diameter of 100-200 nm. The saturation magnetization of the nanorings is 39.5 emu g(-1) at room temperature. The MRI images indicate that these kind of nanorings have the potential application in diagnostics as a T(2) MRI contrast agent. This journal is © The Royal Society of Chemistry 2011

V-insertion in Li(Fe,Mn)FePO4

Science.gov (United States)

Wu, T.; Liu, J.; Sun, L.; Cong, L.; Xie, H.; Abdel-Ghany, A.; Mauger, A.; Julien, C. M.

2018-04-01

Insertion of 3% vanadium in LiMn1-yFeyPO4 has been investigated, with y = 0.2 corresponding to the highest manganese concentration before the stress/strain field degrades the electrochemical performance. V substitutes for Fe2+ in the trivalent state V3+. This substitution is accompanied with the formation of Fe vacancies while Mn remains in the Mn2+ valence state, leading to a composition LiMn0.8Fe0.2-0.045V0.03□0.015PO4 where □ is a Fe vacancy. The comparison between electrochemical properties of a pristine sample and a sample with 3 mol.% vanadium made of particles with the same morphology (spherical particles with the same dispersion 100-150 nm in size) and same carbon coating (same conductivity of the carbon layer) is reported. Although the vanadium is in the V3+ state at open circuit voltage (2.6 V) before cycling, a reversible V3+/V2+ is observed when the potential of the half-cell is lowered below the redox potential of 1.8 V vs Li+/Li, due to Li-vacancies. The V-insertion improves the electrochemical properties, due to a synergetic effect of an increase of the lithium diffusion coefficient by a factor two and an increase of the electric conductivity at any Li-concentration during the cycling process, in contradiction with prior claims that attributed the increase of conductivity to V-based impurities.

Recuento de bacterias totales en leche cruda de tambos que caracterizan la zona noroeste de Santa Fe y sur de Santiago del Estero Total bacterial count in raw milk of dairy farms that characterize the northwest zone of Santa Fe and south of Santiago del Estero

Directory of Open Access Journals (Sweden)

G.R. Revelli

2004-09-01

Full Text Available Un total de 6.998 muestras de leche cruda de pool de tanque, correspondientes a 55 establecimientos lecheros asociados a la Cooperativa Tambera Nueva Alpina Ltda., fueron recolectadas entre los años 1993 y 2002. Se realizó el Recuento de Microorganismos Aerobios Mesófilos Totales, obteniéndose como resultado un valor medio de 1,2 x 105± 2,4 x 105UFC/ml que caracteriza la zona. El año de finalización de la experiencia, se observó un 97% de los tambos evaluados con promedios £ 1,0 x 105UFC/ml. Solamente un 3% sobrepasa este límite, no encontrándose establecimientos con niveles superiores a 1,5 x 105UFC/ml. Al relacionar este indicador con parámetros composicionales, las correlaciones más significativas resultaron para: Recuento de Bacterias Totales vs Acidez (r = 0,292; P A total of 6.998 raw milk samples of bulk tank, belonging to 55 dairy farms associated to the Cooperativa Tambera Nueva Alpina Ltda., were collected between the years 1993 and 2002. The Total Mesophilic Aerobic Microorganisms Count was analyzed, obtaining a medium value of 1.2 x 105± 2.4 x 105CFU/ml that characterizes the zone. The final year of experience, observed a 97% of dairy farms evaluated with averages £ 1,0 x 105CFU/ml. Only a 3% it surpasses this limit, not being found establishments with levels over 1.5 x 105CFU/ml. Relating this indicators with compositionals parameters, the most significant correlation resulted for: Total Bacterial Count vs Acidity (r = 0.292; P < 0.001 and Total Bacterial Count vs Freezing Point (r = 0.157; P < 0.001. The microbiological quality in raw milk of dairy farms belonging to the northwest zone of Santa Fe and south of Santiago del Estero showed a significant improvement during this time.

78 FR 47007 - National Environmental Policy Act; Santa Susana Field Laboratory

Science.gov (United States)

2013-08-02

... project Web site address listed below. http://www.nasa.gov/agency/nepa/news/SSFL.html . ADDRESSES...; Santa Susana Field Laboratory AGENCY: National Aeronautics and Space Administration (NASA). ACTION... Environmental Cleanup Activities for the NASA-administered portion of the Santa Susana Field Laboratory (SSFL...

Observation of hidden atomic order at the interface between Fe and topological insulator Bi2Te3.

Science.gov (United States)

Sánchez-Barriga, Jaime; Ogorodnikov, Ilya I; Kuznetsov, Mikhail V; Volykhov, Andrey A; Matsui, Fumihiko; Callaert, Carolien; Hadermann, Joke; Verbitskiy, Nikolay I; Koch, Roland J; Varykhalov, Andrei; Rader, Oliver; Yashina, Lada V

2017-11-22

To realize spintronic devices based on topological insulators (TIs), well-defined interfaces between magnetic metals and TIs are required. Here, we characterize atomically precisely the interface between the 3d transition metal Fe and the TI Bi 2 Te 3 at different stages of its formation. Using photoelectron diffraction and holography, we show that after deposition of up to 3 monolayers Fe on Bi 2 Te 3 at room temperature, the Fe atoms are ordered at the interface despite the surface disorder revealed by our scanning-tunneling microscopy images. We find that Fe occupies two different sites: a hollow adatom deeply relaxed into the Bi 2 Te 3 quintuple layers and an interstitial atom between the third (Te) and fourth (Bi) atomic layers. For both sites, our core-level photoemission spectra and density-functional theory calculations demonstrate simultaneous chemical bonding of Fe to both Te and Bi atoms. We further show that upon deposition of Fe up to a thickness of 20 nm, the Fe atoms penetrate deeper into the bulk forming a 2-5 nm interface layer containing FeTe. In addition, excessive Bi is pushed down into the bulk of Bi 2 Te 3 leading to the formation of septuple layers of Bi 3 Te 4 within a distance of ∼25 nm from the interface. Controlling the magnetic properties of the complex interface structures revealed by our work will be of critical importance when optimizing the efficiency of spin injection in TI-based devices.

Crystal structure of Fe2TiO5

International Nuclear Information System (INIS)

Shiojiri, M.; Sekimoto, S.; Maeda, T.; Ikeda, Y.; Iwauchi, K.

1984-01-01

The crystal structure of metal pseudobrookite, Fe 2 TiO 5 , is determined from high-resolution electron microscopy images observed and their computer simulated images, with the aid of electron diffraction and X-ray powder diffraction. The new structure has a monoclinic unit, containing eight molecules, with a = 2.223, b = 0.373, c = 0.980 nm, and β = 116.2 0 . The Fe, Ti, and O atoms occupy the positions (4c), +-(u, 0, w; 1/2 + u, 1/2, w), of C 2 3 (C2). The most probable parameters u and w, of Fe(1 to 4), Ti(1, 2), and O(1 to 10) are given. (author)

Multi-jump magnetic switching in ion-beam sputtered amorphous Co20Fe60B20 thin films

International Nuclear Information System (INIS)

Raju, M.; Chaudhary, Sujeet; Pandya, D. K.

2013-01-01

Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co 20 Fe 60 B 20 (5–75 nm) thin films grown on Si/amorphous SiO 2 are reported. While such multi-jump behavior is observed in CoFeB(10 nm) film when the magnetic field is applied at 10°–20° away from the easy-axis, the same is observed in CoFeB(12.5 nm) film when the magnetic field is 45°–55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 °C. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices

Effects of thickness and annealing condition on magnetic properties and thermal stabilities of Ta/Nd/NdFeB/Nd/Ta sandwiched films

Science.gov (United States)

Liu, Wen-Feng; Zhang, Min-Gang; Zhang, Ke-Wei; Zhang, Hai-Jie; Xu, Xiao-Hong; Chai, Yue-Sheng

2016-11-01

Ta/Nd/NdFeB/Nd/Ta sandwiched films are deposited by magnetron sputtering on Si (100) substrates, and subsequently annealed in vacuum at different temperatures for different time. It is found that both the thickness of NdFeB and Nd layer and the annealing condition can affect the magnetic properties of Ta/Nd/NdFeB/Nd/Ta films. Interestingly, the thickness and annealing temperature show the relevant behaviors that can affect the magnetic properties of the film. The high coercivity of 24.1 kOe (1 Oe = 79.5775 A/m) and remanence ratio (remanent magnetization/saturation magnetization) of 0.94 can be obtained in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed for 3 min at 1023 K. In addition, the thermal stability of the film is also linked to the thickness of NdFeB and Nd layer and the annealing temperature as well. The excellent thermal stability can be achieved in a Ta/Nd(250 nm)/NdFeB(600 nm)/Nd(250 nm)/Ta film annealed at 1023 K. Program supported by the National Natural Science Foundation of China (Grant No. 51305290), the Higher Education Technical Innovation Project of Shanxi Province, China (Grant No. 2013133), the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals of Shanxi Province, China (Grant No. 2015003), and the Program for the Key Team of Scientific and Technological Innovation of Shanxi Province, China (Grant No. 2013131009).