Critical Behavior of a Three-State Potts Model on a Voronoi Lattice

We use the single-histogram technique to study the critical behavior of the three-state Potts model on a (random) Voronoi-Delaunay lattice with size ranging from 250 to 8000 sites. We consider the effect of an exponential decay of the interactions with the distance,$J(r)=J_0\exp(-ar)$, with $a>0$, and observe that this system seems to have critical exponents $\gamma$ and $\nu$ which are different from the respective exponents of the three-state Potts model on a regular square lattice. However, the ratio $\gamma/\nu$ remains essentially the same. We find numerical evidences (although not conclusive, due to the small range of system size) that the specific heat on this random system behaves as a power-law for $a=0$ and as a logarithmic divergence for $a=0.5$ and $a=1.0$Comment: 3 pages, 5 figure

Aeolian transport of sand

Abstract.: The airborne transport of particles on a granular surface by the saltation mechanism is studied through numerical simulation of particles dragged by turbulent air flow. We calculate the saturated flux qs and show that its dependence on the wind strength u* is consistent with several empirical relations obtained from experimental measurements. We propose and explain a new relation for fluxes close to the threshold velocity ut, namely, qs=a(u*-ut)α with α≈2. We also obtain the distortion of the velocity profile of the wind due to the drag of the particles and find a novel dynamical scaling relation. We also obtain a new expression for the dependence of the height of the saltation layer as function of the strength of the win

A co-cretion process for premium traditional portuguese pocket knifes

During an eight weeks DEMOLA project, from March to June 2019, a team of five students together with the representative of Martins Cutelaria Tradicional de Palaçoulo, putted into practice the steps towards an innovative design of a new premium series, the “Portuguese History Collection”. This design project was driven through a co-creation process with the traditional Portuguese pocket knifes company Martins Cutelaria Tradicional de Palaçoulo, based in the old village of Palaçoulo, Bragança, Portugal (see [1]). Martins Cutelaria, which has a long history in the design, production and innovation of traditional Portuguese pocket knifes, launched the challenge of designing a new premium line for their traditional pocket knifes segment. The challenge was to innovate while keeping untouched the identity, tradition and the solid values that are the pillars of the company since it was founded in 1954. Based on the company's motto: “Ter uma navalha Martins Palaçoulo, é ter nas mãos um pedaço da nossa história."(*) and inspired by the fact that the year 2019 celebrates the 500th anniversary of the departure of the navigator Fernão de Magalhães for his circumnavigation of the globe by sea, the team worked out the new pocket knifes collection “Portuguese History Collection – The Navigations”.info:eu-repo/semantics/publishedVersio

O capital social nas relações sociais de agricultores parceiros dos projetos Tipitamba e Raízes da Terra, no Nordeste Paraense.

Este trabalho teve como objetivo analisar o capital social em comunidades rurais do nordeste paraense. As ferramentas utilizadas para coleta de dados foram: o Questionário Integrado para Medir Capital Social ? QI MCS e entrevistas semi-estruturadas a partir QI MCS composto de perguntas abertas e fechadas. Dos 32 agricultores entrevistados 100% fazem parte da associação e dos projetos Tipitamba e Raízes da Terra, porém 44% destes agricultores participam de outros diferentes grupos dentre os quais destacamos: futebol, igreja, mutirão, conselho escolar, associação de meliponicultores de Igarapé Açu, grupo de agricultor São Sebastião e horta orgânica. Quanto à participação dos agricultores parceiros ou membros de sua família nas atividades em grupo, as mais citadas foram: reuniões na associação, intercâmbio, mutirão, dia de campo. Os dados apontam que os agricultores das comunidades São João, Novo Brasil e Aparecida participam mais de grupos que os agricultores de Nova Olinda e Nossa Senhora do Rosário. Os agricultores das comunidades de São João, Nova Olinda e Novo Brasil e Aparecida são os que melhor interagem interna e externamente a comunidade, porque participam mais das reuniões das associações, dos dias de campo e dos intercâmbios

An extended-phase-space dynamics for the generalized nonextensive thermostatistics

We apply a variant of the Nose-Hoover thermostat to derive the Hamiltonian of a nonextensive system that is compatible with the canonical ensemble of the generalized thermostatistics of Tsallis. This microdynamical approach provides a deterministic connection between the generalized nonextensive entropy and power law behavior. For the case of a simple one-dimensional harmonic oscillator, we confirm by numerical simulation of the dynamics that the distribution of energy H follows precisely the canonical q-statistics for different values of the parameter q. The approach is further tested for classical many-particle systems by means of molecular dynamics simulations. The results indicate that the intrinsic nonlinear features of the nonextensive formalism are capable to generate energy fluctuations that obey anomalous probability laws. For q<1 a broad distribution of energy is observed, while for q>1 the resulting distribution is confined to a compact support.Comment: 4 pages, 5 figure

Aeolian transport layer

We investigate the airborne transport of particles on a granular surface by the saltation mechanism through numerical simulation of particle motion coupled with turbulent flow. We determine the saturated flux $q_{s}$ and show that its behavior is consistent with a classical empirical relation obtained from wind tunnel measurements. Our results also allow to propose a new relation valid for small fluxes, namely, $q_{s}=a(u_{*}-u_{t})^{\alpha}$, where $u_{*}$ and $u_{t}$ are the shear and threshold velocities of the wind, respectively, and the scaling exponent is $\alpha \approx 2$. We obtain an expression for the velocity profile of the wind distorted by the particle motion and present a dynamical scaling relation. We also find a novel expression for the dependence of the height of the saltation layer as function of the wind velocity.Comment: 4 pages, 4 figure

Relações de confiança e solidariedade entre os agricultores parceiros do Projeto Tipitamba, Embrapa Amazônia Oriental: Evidências sobre a formação de capital social.

Este trabalho tem como objetivo avaliar o grau de confiança e solidariedade entre os agricultores das comunidades parceiras do Projeto Tipitamba. O instrumento utilizado para coleta de dados nas comunidades onde ocorreu a pesquisa foi o Questionário Integrado para Medir Capital Social ? QI MCS, proposto por Grootaert et. al. (2003), a partir de um conjunto de estudos e pesquisas desenvolvidos pelos autores sobre o tema. Os dados aqui apontam que a confiança nos últimos 10 anos entre os membros das comunidades São João e Nossa Senhora do Rosário permaneceu o mesmo. Já para as comunidades: Nova Olinda e Novo Brasil e Aparecida à confiança entre os membros das comunidades melhorou. Quanto à confiança em determinados grupos, a pesquisa aponta para um alto grau de confiança em parentes, atores institucionais, professores e agente de saúde, já em grupos como governo local, governo central e comerciantes há uma redução no grau de confiança. Pode-se afirmar que o estabelecimento da confiança e solidariedade tem um papel fundamental na formação, acumulação, manutenção e difusão do capital social, seja nos grupos, nas organizações ou na sociedade e que, por apresentar nuances e fragilidades, altera a configuração e o conteúdo do capital social