O Refino estiriano na Fábrica de Ferro de Ipanema: gestos engendrando cristais em 1885

A fabricação de barras de ferro maleável na Fábrica de Ferro de Ipanema é examinada com base na descrição do processo de refino do ferro-gusa feita pelo engenheiro Dupré, em 1884, e pela análise da microestrutura de alguns exemplares obtidos no Museu Nacional, no Rio de Janeiro, em 2014. Barras desse tipo foram utilizadas nas estradas de ferro do século 19. São contextualizados e explicados, a luz dos conhecimentos atuais, os gestos dos operadores do refino. As heterogeneidades microestruturais nelas observadas são similares às citadas na literatura sobre peças contemporâneas. Foi possível correlacionar a composição química do minério de ferro de Ipanema com a composição das inclusões de escória presentes naqueles objetos, parâmetro viável para estabelecer a “assinatura química” das barras lá fabricadas.The production of wrought iron bars at Ipanema Ironworks is examined based on the description written by Dupré, in 1884, about the refining process used there, and by the microstructural analysis of samples obtained in the collections of Museu Nacional, in Rio de Janeiro, in 2014. Similar bars were used in the Brazilian railroads of the 19 Century. The microstructural inhomogeneities observed in those bars are similar to those described in the international literature about contemporary pieces. It is possible to correlate the chemical composition of the iron ore used at Ipanema to the composition of crystals found in the slag inclusions, becoming a viable parameter to establish a “chemical signature” of the bars there made

Anomalous loss hysteresis loop

This paper discusses the anomalous loss behavior in two electrical steels types. Starting from a non oriented electrical steel coil, three groups of samples with different grain sizes were produced. Grain oriented steel samples were produced from a commercially available material. The experimental procedure was performed by means of magnetic properties measurements using an Epstein frame. A procedure to draw the hysteresis curve of the anomalous loss is proposed. The results reported that anomalous loss has a different behavior when the two electrical steel types are compared. In non oriented steels anomalous loss is concentrated at the low induction region. In grain oriented steels, a remarkable participation of high induction region is observedIPTCAPE

An analysis of Brazilian sugarcane bagasse ash behavior under thermal gasification.

Background: Ashes from sugarcane were analyzed by X-ray fluorescence, ash content, X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). FactSage 6.4 database software was used to estimate viscosity at high temperatures (900 - 1550°C) of them. Results: The results showed that although ashes from sugarcane bagasse contain silica, most of its SiO2 is from soil contamination. Higher and lower silica samples treated at 1350°C for 20 minutes showed that the fine portion of fraction of the ashes melted at this temperature. Conclusions: The melting phase could act as sticking flux for the coarse silica particles on the gasifier bottom wall, which could compromise the gasification process

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements