4,000 research outputs found

    Stress induced magnetic anisotropy on BaTiO3-CoFe2O4 nanogranular composite thin films

    Get PDF
    The influence of stress on the magnetic properties of BaTiO3-CoFe2O4 nanocomposites deposited by laser ablation on platinum covered Si(001) substrates, was characterized. The cobalt ferrite phase was under compressive strain in the growth direction that progressively relaxed as its concentration increased. A stress induced perpendicular magnetic anisotropy was observed, that decreased with increasing CoFe2O4 content, due to the relaxation of stress in the films.This work has been financially supported by the Portuguese Foundation for Science and Technology (FCT) and FEDER, through the projects POCI/CTM/60181/2004, FEDER/POCTI/0155/94, and through the Associated Laboratory-IN

    Productiveness Evaluation of a Machine Tool Manual Setup Compared with Automated CNC Machine

    Full text link
    The automatic tool change of machine tools affects the productive efficiency in several ways such as starving time reduction, increase/decrease of production rate as well reliability and reduce the process related costs of manufacturing. Based on that background an analysis of experimental scenarios of manual tool change versus automatic tool change was made in order to compare and evaluate its related production rate

    Cobalt ferrite thin films deposited by electrophoresis on p-doped Si substrates

    Get PDF
    The structural and magnetic properties of cobalt ferrite (CoFe2O4) thin films deposited by electrophoresis on p-doped Si(001) substrates have been characterized. The films were polycrystalline and composed by cobalt ferrite with the cubic spinnel structure. The observed decrease of the coercive field with the sixth power of the grain size was indicative of a competition between the magnetocrystalline anisotropy and the exchange coupling energy, on these randomly oriented nanosized grained films.J. Barbosa and M.P. Proenca gratefully acknowledge a PhD grant from Fundacao para a Ciencia e Tecnologia (SFRH/BD/41913/2007 and SFRH/BD/43440/2008, respectively)

    High-field magnetoresistance of La0.67Sr0.33MnO3 thin films deposited on LiNbO3 substrates

    Get PDF
    Colossal magnetoresistive manganites have been widely studied due to their potential use in sensor and device applications. In this work, La0.67Sr0.33MnO3 thin films were deposited by pulsed laser ablation on LiNbO3 substrates and magnetoresistance measurements were performed using pulsed magnetic fields up to 25 T. The corresponding magnetoconductance of the films was fitted in order to obtain the grain boundary (GB) contribution to the transport properties. The observed temperature dependence of the fitting parameters was indicative of antiferromagnetism across GB spins and reflected the progressive reduction of magnetic ordering with increasing temperature.This work was supported in part by Project No. FEDER/POCTI 155/94 from Fundação para a Ciência e Tecnologia (FCT). I.T. Gomes, A. Pereira and J. Barbosa gratefully acknowledge Ph.D. grants (SFRH/BD/36348/2007, SFRH/BD/22373/2005 and SFRH/BD/41913/2007, respectively) from FCT

    Development of novel magnetoliposomes containing nickel ferrite nanoparticles covered with gold for applications in thermotherapy

    Get PDF
    Multifunctional nanosystems combining magnetic and plasmonic properties are a promising approach for cancer therapy, allowing magnetic guidance and a local temperature increase. This capability can provide a triggered drug release and synergistic cytotoxic effect in cancer cells. In this work, nickel ferrite/gold nanoparticles were developed, including nickel ferrite magnetic nanoparticles decorated with plasmonic gold nanoparticles and core/shell nanostructures (with a nickel ferrite core and a gold shell). These nanoparticles were covered with a surfactant/lipid bilayer, originating liposome-like structures with diameters below 160 nm. The heating capacity of these systems, upon excitation with light above 600 nm wavelength, was assessed through the emission quenching of rhodamine B located in the lipid layer. The developed nanosystems show promising results for future applications in thermotherapy.This research was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2019) and through the research project PTDC/QUI-QFI/28020/2017 (POCI-01-0145-FEDER-028020), financed by European Fund of Regional Development (FEDER), COMPETE2020, and Portugal2020. The magnetic measurements were supported by projects UTAP-EXPL/NTec/0046/2017, NORTE-01-0145-FEDER-028538, and PTDC/FIS-MAC/29454/2017. I.S.R.R. acknowledges FCT for a research grant under CF-UM-UP Strategic Funding (UID/FIS/04650/2019)

    Nitrogen Metabolism in Lactating Goats Fed with Diets Containing Different Protein Sources

    Get PDF
    This study aimed to evaluate urea excretion, nitrogen balance and microbial protein synthesis in lactating goats fed with diets containing different protein sources in the concentrate (soybean meal, cottonseed meal, aerial part of cassava hay and leucaena hay). Four Alpine goats whose mean body weight was 42.6±6.1 kg at the beginning of the experiment, a mean lactation period of 94.0±9.0 days and a production of 1.7±0.4 kg of milk were distributed in a 4×4 Latin square with four periods of 15 days. Diets were formulated to be isonitrogenous, containing 103.0 g/kg of CP, 400 g/kg of Tifton 85 hay and 600 g/kg of concentrate. Diet containing cottonseed meal provided (p<0.05) increased excretion of urea and urea nitrogen in the urine (g/d and mg/kg of BW) when compared with leucaena hay. The diets affected the concentrations of urea nitrogen in plasma (p<0.05) and excretion of urea nitrogen in milk, being that soybean meal and cottonseed meal showed (p<0.05) higher than the average aerial part of the cassava hay. The use of diets with cottonseed meal as protein source in the concentrate in feeding of lactating goats provides greater nitrogen excretion in urine and negative nitrogen balance, while the concentrate with leucaena hay as a source of protein, provides greater ruminal microbial protein synthesis

    Magnetic liposomes containing calcium ferrite nanoparticles for breast cancer therapy

    Get PDF
    In this work, calcium ferrite nanoparticles were prepared and characterized. The structural and magnetic properties of the nanoparticles were evaluated by XRD, TEM and SQUID. The synthesized nanoparticles were either entrapped in liposomes, originating aqueous magnetoliposomes (AMLs), or covered with a lipid bilayer, forming solid magnetoliposomes (SMLs). Magnetoliposomes present average diameters around 150 nm, suitable for biomedical applications. The magnetoliposomes were loaded with new potential anticancer drugs, thienopyridine derivatives, with a strong antitumor activity against breast cancer cells.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UID/FIS/04650/2013) and of CQUM (UID/QUI/00686/2013). FCT, POPH-QREN and FSE are acknowledged for the PhD grants of A. R. O. Rodrigues (SFRH/BD/90949/2012) and V. A. Machado (SFRH/BD/77373/2011) and for financial support to MAP-Fis Joint Doctoral Programme.info:eu-repo/semantics/publishedVersio

    Crescimento do algodoeiro herbáceo sob déficit hídrico.

    Get PDF
    Um trabalho foi desenvolvido em casa de vegetação na Embrapa Algodão em Campina Grande, PB, com o objetivo de avaliar déficits hídricos no crescimento de duas cultivares de algodoeiro herbáceo. Foi utilizado o delineamento experimental blocos casualizados, com 4 repetições, em combinação fatorial 4 x 2 (T1 ? irrigado, T2, T3 e T4 ? 14 dias sem irrigação nas fases de botão floral, flor e maçã, respectivamente) x (cultivares BRS 286 e BRS 336 de algodoeiro herbáceo). Concluiu-se que ambas as cultivares se comportaram de forma similar frente aos diferentes déficits hídricos aplicados no estudo e que a aplicação de déficits após a fase de floração não reduziu o crescimento em altura da planta, diâmetro do caule e número de folhas por planta das cultivares de algodoeiro herbáceo estudadas

    The Holographic Model of Dark Energy and Thermodynamics of Non-Flat Accelerated Expanding Universe

    Get PDF
    Motivated by recent results on non-vanishing spatial curvature \cite{curve} we employ the holographic model of dark energy to investigate the validity of first and second laws of thermodynamics in non-flat (closed) universe enclosed by apparent horizon RAR_A and the event horizon measured from the sphere of horizon named LL. We show that for the apparent horizon the first law is roughly respected for different epochs while the second laws of thermodynamics is respected while for LL as the system's IR cut-off first law is broken down and second law is respected for special range of deceleration parameter. It is also shown that at late-time universe LL is equal to RAR_A and the thermodynamic laws are hold, when the universe has non-vanishing curvature. Defining the fluid temperature to be proportional to horizon temperature the range for coefficient of proportionality is obtained provided that the generalized second law of thermodynamics is hold.Comment: 12 pages, no figure, abstract and text extended, references added, accepted for publication in JCA
    corecore