This work presents an atmospheric-pressure protocol for generating and characterizing cyclopentane hydrate slurries. Water-in-oil emulsions containing 30 and 40
Hydrogen embrittlement (HE) remains a critical challenge in steels, particularly as hydrogen gains importance as a clean energy carrier. Direct microstructural evidence of HE mechanisms is difficult to obtain due to the high mobility of hydrogen and the instability of crack propagation. In this study, we introduce a controlled experimental approach using low-energy proton implantation to locally introduce hydrogen into 22MnB5 press hardened steel. This technique, adapted from prior investigations in silicon, confines hydrogen-induced effects to a well-defined depth, enabling focused nano-scale analysis by transmission electron microscopy. The results reveal the nucleation of hydrogen-stabilized nano-cavities aligned in one-dimensional rafts, which subsequently coalesce into nano-cracks within the martensitic matrix. These findings provide direct experimental insight into the incipience of HE, supporting the synergistic action of hydrogen-enhanced localized plasticity and hydrogen-enhanced decohesion. The proposed methodology offers a promising route to systematically investigate the onset of hydrogen embrittlement in metallurgy with nanoscale resolution.
We propose a methodology to detect weak Lorentz-violating (LV) backgrounds through the nonlinear shift photocurrent in noncentrosymmetric crystals. Using a spinful Rice–Mele model, we show that a LV background induces a momentum-odd correction to the Bloch Hamiltonian that reshapes the phase of the interband dipole matrix elements. As a result, the shift conductivity develops a robust π-periodic modulation as a function of the angle of a perpendicularly applied static electric field, in contrast to a weakly 2π-periodic response of the Lorentz-symmetric case. This change in angular periodicity provides a signature of LV effects which can be directly identified through a photocurrent measurement. For realistic optical intensities, the predicted signal lies in the picoampere range, which can be enhanced in a matrix of weakly interacting chains, allowing sensitivity to LV coupling strengths of the order of ξ∼10^-24 C m. These results establish nonlinear optical transport as a viable probe of emergent LV effects in solid-state systems.
Diante desse contexto, o estudo busca compreender de que maneira a Educação Ambiental Crítica contribui para a formação de sujeitos políticos capazes de enfrentar os desafios socioambientais do século XXI, analisando seu papel na promoção da consciência crítica, da justiça socioambiental e da emancipação humana. O estudo fundamenta-se teoricamente no diálogo entre autores clássicos da Educação e do Saber Ambiental — Freire (1996), Leff (2001), Loureiro (2004), Carvalho (2012) e Brandão (2006) — e produções científicas e relatórios internacionais recentes (UNESCO, 2020; IPBES, 2022; Jacobi, 2022; IPCC, 2023). Parte-se do entendimento de que a crise ambiental contemporânea ultrapassa os limites ecológicos, configurando-se como uma crise civilizatória, ética e socioeconômica decorrente de um modelo de desenvolvimento extrativista, predatório e concentrador. Metodologicamente, trata-se de uma pesquisa qualitativa, exploratória e descritiva, desenvolvida via revisão bibliográfica integrada ao recorte analítico da comunidade quilombola de Graúna, em Itapemirim-ES. O estudo evidencia que a Educação Ambiental, quando assumida em sua dimensão transformadora, territorializada e antirracista, é capaz de fortalecer os saberes ancestrais, combater o racismo ambiental e promover a emancipação humana. Conclui-se que a formação de sujeitos críticos exige a articulação entre conhecimento científico, justiça socioambiental e a valorização das epistemologias e práticas comunitárias de resistência.
