Gadolinium substitution effect on the thermomagnetic properties of Ni ferrite ferrofluids

Versión enviada del artículo; finalmente publicado en: Jacobo, S. E., Arana, M. y Bercoff, P. G. (2016). Gadolinium substitution effect on the thermomagnetic properties of Ni ferrite ferrofluids. Journal of Magnetism and Magnetic Materials, 415, 30-34. https://doi.org/10.1016/j.jmmm.2015.11.047Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina.Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina.Fil: Jacobo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina.Fil: Arana, Mercedes. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Fil: Arana, Mercedes. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Fil: Arana, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Fil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Fil: Bercoff, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.This work is focused on the characterization of Ni-ferrite nanocrystals and their subsequent doping with Gd, in an attempt to explore Gd inclusion in the thermomagnetic properties of prepared ferrofluids. Spinel ferritesNiFe2O4, and NiFe1.88Gd0.12O4 were prepared by the auto-combustion method. The substituted sample is obtained with a small amount of Gd inclusion and the excess appears as GdFeO3. The smallest nanoparticles of both samples were properly coated and dispersed in kerosene. Thermal conductivities of the produced ferrofluids were measured at 25 °C in a magnetic field. There is a significant enhancement in thermal conductivity of the ferrofluid prepared with NiGd ferrite with respect to the one with Ni ferrite, in presence of a magnetic field. This effect is directly related to the well-known magnetocaloric effect of Gd.info:eu-repo/semantics/submittedVersionFil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina.Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina.Fil: Jacobo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina.Fil: Arana, Mercedes. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Fil: Arana, Mercedes. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Fil: Arana, Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.Fil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina.Fil: Bercoff, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Cerámico

Formation of a magnetic composite by reduction of Co-Nd doped strontium hexaferrite in a hydrogen gas flow

Co-Nd strontium hexaferrite nanoparticles synthesized by the self-combustion method were treated in a hydrogen flow at different temperatures and times. The samples were characterized structurally by scanning electron microscopy and X-ray diffraction and magnetically with a vibrating sample magnetometer. Phase identification showed decomposition of the hexaferrite structure into Fe 3O 4 and different strontium mixed oxides. The sample treated at 500 °C for 30 minutes shows good magnetic properties due to the formation of a magnetite/hexaferrite composite. In this case magnetization is very close to the original sample while the coercivity slightly diminishes. The hexagonal phase is almost completely transformed into different oxides at a reducing temperature of 500 °C for 120 minutes. The obtained results are analyzed in terms of the phase composition and of the magnetic susceptibility of the studied samples.Fil: Herme, Carlos Alberto. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bercoff, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Corrosion of steel alloys with ferrite coating

Ponencia presentada en el Congreso Internacional de Metalurgia y Materiales 14º SAM-CONAMET/IBEROMAT/MATERIA. Santa Fe, Argentina, 21 al 24 de octubre de 2014The corrosion protection offered by coatings of hexagonal Sr ferrites on steel samples in the presence of chloride was evaluated by electrochemical techniques. Different samples were prepared using Nd-Co doped and un-doped strontium hexaferrite coatings, and tested in sodium chloride (NaCl) solutions during 45 days. Time variation of the corrosion potential and polarization resistance measurements were carried out for each of the tested steel samples at different immersion times. All the samples were characterized by scanning electronic microscopy and energy dispersive X-ray analysis (SEM/EDX). All the tested ferrite coatings offered good protection and corrosion resistance, which increased as the samples remained immersed in the chloride solution. When a concentrated NaCl solution was employed as corrosive agent, the coatings continued offering protection and the currents increased one order of magnitude, while remaining constant with the variation of the immersion time. The samples coated with doped ferrite showed the highest resistance to the aggressive environment, with low corrosion rates even after 48 hours of immersion in NaCl 0.5 M.Fil: Herme, Carlos Alberto. Universidad de Buenos Aires. Facultad de Ingeniería. Laboratorio de Fisicoquímica de Materiales Cerámicos Electrónicos; Argentina.Fil: Herme, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina.Fil: Herme, Carlos Alberto. Universidad de Buenos Aires. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina.Fil: Cicileo, Gabriela Perla. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Centro de Investigaciones en Sólidos. División Corrosión; Argentina.Fil: Cicileo, Gabriela Perla. Ministerio de Defensa de la Nación. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Centro de Investigaciones en Sólidos. División Corrosión; Argentina.Fil: Bercoff, Paula Gabriela. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Bercoff, Paula Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Facultad de Ingeniería. Laboratorio de Fisicoquímica de Materiales Cerámicos Electrónicos; Argentina.Fil: Jacobo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina.Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Instituto de Tecnologías y Ciencias de la Ingeniería; Argentina.Otras Ciencias Física

3-Amino-1,2,4-Triazole Tetramer: Electrical Conductivity Related To The Doped Degree

A study on the electrical conductivity and thermal behavior of the new oligomer 3-amino-1,2,4- triazole tetramer, related to the doped degree and temperature in the range of 300 K ≤ T ≤ 370 K has been performed. Sample doped in acid medium, at room temperature, showed the highest electrical conductivity (7.0 10-3 S / cm), whereas neutral or basic samples presented two orders minor values of electrical conductivity. Morphological and structural characteristics are discussed. This new organic semiconductor can be prepared as a thin film in order to explore its optical properties. The results show that the energy at which absorption starts corresponds to the direct band gap at 1.7 eV. As the organic semiconductor OATA may be used to prepare large-area thin film and flexible device on low-price, flexible substrates by means of solution method, the authors deduce that this oligomer may have an important application potential in UV-Vis optoelectronic detecting or lighting fieldFil: Lamanna, Melisa Elsa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física. Laboratorio de Polímeros y Materiales Compuestos; Argentina; Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina;Fil: de la Horra, E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería;Fil: Jacobo, Silvia Elena. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería;Fil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina; Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina

Acid-base behavior of an oligomer of 3-amino-1,2,4-triazole

We report the acid-base behavior of OATA, an oligomer synthesized from 3-amino-1,2,4-triazole (ATA). We analyze the UV-vis spectroscopy at different media, and we analyze and discuss the acid-base equilibria taking into account tautomeric equilibria at different pH. The low aqueous solubility at neutral pH can be attributed to the neutral form. Indeed, OATA was synthesized in an ordinary filter paper, which can be used as a sensor for ammonia as well as endpoint indication. Using the OATA-containing paper, ammonia concentrations in a solution as low as 5 ppm could be measured.Fil: Lamanna, Melisa Elsa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: De La Horra, Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Sanabria, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: Jacobo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; ArgentinaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism

Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass