Uniform materials and the multiplicative decomposition of the deformation gradient in finite elasto-plasticity

In this work we analyze the relation between the multiplicative decomposition $\mathbf F=\mathbf F^{e}\mathbf F^{p}$ of the deformation gradient as a product of the elastic and plastic factors and the theory of uniform materials. We prove that postulating such a decomposition is equivalent to having a uniform material model with two configurations - total $\phi$ and the inelastic $\phi_{1}$. We introduce strain tensors characterizing different types of evolutions of the material and discuss the form of the internal energy and that of the dissipative potential. The evolution equations are obtained for the configurations $(\phi,\phi_{1})$ and the material metric $\mathbf g$. Finally the dissipative inequality for the materials of this type is presented.It is shown that the conditions of positivity of the internal dissipation terms related to the processes of plastic and metric evolution provide the anisotropic yield criteria

A Fractional Model of Complex Permittivity of Conductor Media with Relaxation: Theory vs. Experiments

Moving from the study of plasmonic materials with relaxation, in this work we propose a fractional Abraham-Lorentz-like model of the complex permittivity of conductor media. This model extends the Ciancio-Kluitenberg, based on the Mazur-de Groot non-equilibrium thermodynamics theory (NET). The approach based on NET allows us to link the phenomenological function of internal variables and electrodynamics variables for a large range of frequencies. This allows us to closer reproduce experimental data for some key metals, such as Cu, Au and Ag. Particularly, our fitting significantly improves those obtained by Rakic and coworkers and we were able to operate in a larger range of energy values. Moreover, in this work we also provide a definition of a substantial fractional derivative, and we extend the fractional model proposed by Flora et al

Thermomechanics of Interstitial Working at Liquid Boundaries

A model of material interface, for which the metric tensor is regarded as an internal variable, is considered. Both a local and a non-local evolution equation for such a variable are analyzed. The consequences of the second law of thermodynamics are derived in both cases

Application of the Mesoscopic Theory to Dipolar Media

Mesoscopic continuum theory is a way to deal with complex materials, i.e. materials with an internal structure, which can change under the action of external elds, within continuum theory. In the mesoscopic theory eld quantities are introduced, which depend not only on position and time, but also on an additional, so called mesoscopic variable. In our case this additional variable is the orientation of a dipole. The orientation distribution function (ODF) gives the fraction of dipoles of a particular orientation. The magnetization is proportional to the rst moment of the ODF. Balance equations for the mesoscopic elds, and an equation of motion for the distribution function have been derived in the general case. With some additional assumptions these equations are used here to derive a relaxation equation for the magnetization. The linear limit case of this relaxation equation is the well known DEBYE equation

Health Screening for Emerging and Non-Communicable Disease Burdens Among the Global Poor

Among adults in rural Malawi, population health screening for high blood pressure (BP) led to a 22-percentage point drop in the likelihood of being hypertensive four years later. Individuals with elevated BP received a referral letter upon initial screening; at follow-up, they had lower BP and higher self-reported mental health than individuals with similar BP who were just below the threshold for referral. Population health screenings can reduce the burden of non-communicable diseases in low-income countries

Health Screening for Emerging Disease Burdens Among the Global Poor

Evidence for the effectiveness of population health screenings to reduce the burden of non-communicable diseases in low income countries remains very limited. We investigate the sustained effects of a health screening in Malawi where individuals received a referral letter if they had elevated blood pressure. Using a regression discontinuity design and a matching estimator, we find that receiving a referral letter reduced blood pressure and the probability of being hypertensive by about 22 percentage points four years later. These lasting effects are explained by a 20 percentage points increase in the probability of being diagnosed with hypertension. There is also evidence of an increase in the uptake of medication, while we do not identify improvements in hypertension-related knowledge or risk behaviors. The health screening had some positive effects on mental health. Overall, this study suggests that population-based hypertension screening interventions are an effective tool to improve health in low-income contexts

Mortality Risk Information, Survival Expectations and Sexual Behaviors

Individuals in low-income settings are often overly pessimistic about their own survival, suggesting that better knowledge about survival risks might encourage investments in health. This paper provides evidence from a randomized experiment that provided mature adults aged 45+ in Malawi with information about mortality risks. Treated individuals are less likely to engage in risky sexual practices one year after the intervention, and they increase other forward-looking behaviors such as investments in agriculture. Expectations of HIV+ people living longer, which makes the pool of potential partners riskier, are a primary driver of reduced sexual risk taking in response to the intervention

Multiple double-exchange mechanism by Mn2+^{2+}-doping in manganite compounds

Double-exchange mechanisms in RE$_{1-x}$AE$_{x}$MnO$_{3}$ manganites (where RE is a trivalent rare-earth ion and AE is a divalent alkali-earth ion) relies on the strong exchange interaction between two Mn$^{3+}$ and Mn$^{4+}$ ions through interfiling oxygen 2p states. Nevertheless, the role of RE and AE ions has ever been considered "silent" with respect to the DE conducting mechanisms. Here we show that a new path for DE-mechanism is indeed possible by partially replacing the RE-AE elements by Mn$^{2+}$-ions, in La-deficient La$_{x}$MnO$_{3-\delta}$ thin films. X-ray absorption spectroscopy demonstrated the relevant presence of Mn$^{2+}$ ions, which is unambiguously proved to be substituted at La-site by Resonant Inelastic X-ray Scattering. Mn$^{2+}$ is proved to be directly correlated to the enhanced magneto-transport properties because of an additional hopping mechanism trough interfiling Mn$^{2+}$-ions, theoretically confirmed by calculations within the effective single band model. The very idea to use Mn$^{2+}$ both as a doping element and an ions electronically involved in the conduction mechanism, has never been foreseen, revealing a new phenomena in transport properties of manganites. More important, such a strategy might be also pursed in other strongly correlated materials.Comment: 6 pages, 5 figure