Temperature oscillations of magnetization observed in nanofluid ferromagnetic graphite

We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed to manifestation of finite size effects below the quantum temperature) as well as pronounced temperature oscillations above T=50K (attributed to manifestation of the hard-sphere type pair correlations between ferromagnetic particles in the nanofluid)

Universal reduction of pressure between charged surfaces by long-wavelength surface charge modulation

We predict theoretically that long-wavelength surface charge modulations universally reduce the pressure between the charged surfaces with counterions compared with the case of uniformly charged surfaces with the same average surface charge density. The physical origin of this effect is the fact that surface charge modulations always lead to enhanced counterion localization near the surfaces, and hence, fewer charges at the midplane. We confirm the last prediction with Monte Carlo simulations.Comment: 8 pages 1 figure, Europhys. Lett., in pres

Thermodynamic potential with correct asymptotics for PNJL model

An attempt is made to resolve certain incongruities within the Nambu - Jona-Lasinio (NJL) and Polyakov loop extended NJL models (PNJL) which currently are used to extract the thermodynamic characteristics of the quark-gluon system. It is argued that the most attractive resolution of these incongruities is the possibility to obtain the thermodynamic potential directly from the corresponding extremum conditions (gap equations) by integrating them, an integration constant being fixed in accordance with the Stefan-Boltzmann law. The advantage of the approach is that the regulator is kept finite both in divergent and finite valued integrals at finite temperature and chemical potential. The Pauli-Villars regularization is used, although a standard 3D sharp cutoff can be applied as well.Comment: 16 pages, 5 figures, extended version, title change

A new species of Calacarus Keifer (Acari: Eriophyidae) on papaya in Northeastern Brazil.

Calacarus flagelliseta n.sp. (Acari: Prostigmata: Eriophyidae) is described from Northeastern Brazil based on adults of both sexes collected from papaya leaves

Área irrigada, produção e produtividade das principais hortaliças no Brasil - 1985/1986.

Foi criada e vem sendo gerenciada uma base de dados sobre hortaliças objetivando apoiar o estabelecimento de planos e programas para o desenvolvimento deste setor no país. Os valores médios para os dois anos estudados, 1985 e 1986, possibllltaram concluir que a batata foi a hortaliça com a maior área colhida (158 mil ha) e Irrigada (57 mil ha) evidenciando que 60% da área colhida nao utilizou irrigação.bitstream/item/107318/1/CNPH-DOC.-4-89.pd

Manifestation of finite temperature size effects in nanogranular magnetic graphite

In addition to the double phase transition (with the Curie temperatures T_C=300K and T_{Ct}=144K), a low-temperature anomaly in the dependence of the magnetization is observed in the bulk magnetic graphite (with an average granular size of L=10nm), which is attributed to manifestation of the size effects below the quantum temperature. The best fits of the high-temperature data (using the mean-field Curie-Weiss and Bloch expressions) produced reasonable estimates for the model parameters, such as defects mediated effective spin exchange energy J=12meV (which defines the intragranular Curie temperature T_C) and proximity mediated interactions between neighboring grains (through potential barriers created by thin layers of non-magnetic graphite) with energy J_t=exp(-d/s)J=5.8meV (which defines the intergranular Curie temperature T_{Ct}) with d=1.5nm and s=2nm being the intergranular distance and characteristic length, respectively

Manejo dos restos culturais (soqueira) do algodoeiro como ferramenta de combate às pragas.

bitstream/CPATC-2009-09/20523/1/ct-41.pd