Magnetic separation for wastepaper recycle mills

Journal ArticleAn alternative approach to the conventional washing and flotation techniques for de-inking of mixed office waste (MOW) is magnetic separation. The use of magnetic de-inking has great potential to improve the efficiency of ink removal due to the magnetic content of toners. It is shown experimentally that the magnetic susceptibility of toners typically found in MOW varies from weakly paramagnetic to ferromagnetic. The magnetic de-inking of MOW in itself is not sufficient to achieve a high quality final product due to variations in the magnetic susceptibility of the toner particles. Nevertheless a combination of magnetic separation with flotation appears to be able to produce a final product of superior quality with 92.7% of the dirt removed. Considering these findings appropriate flowsheet modifications are suggested for improved plant performanc

Surface chemistry of pulping and flotation for mixed office wastepaper

Journal ArticleThe effect of pulping reagents on the de-inking flotation of laser printed wastepaper was investigated with regard to the removal efficiency of toner and mineral filler particles at different pH values. These results show that caustic pulping causes the toner to be released from the fibers as larger particles with a reduced hydrophobicity. On the other hand, neutral pulping not only causes the toner to be released as smaller particles but also increases the simultaneous flotation removal of mineral filler particles

Pressure effect in the X-ray intrinsic position resolution in noble gases and mixtures

A study of the gas pressure effect in the position resolution of an interacting X- or gamma-ray photon in a gas medium is performed. The intrinsic position resolution for pure noble gases (Argon and Xenon) and their mixtures with CO2 and CH4 were calculated for several gas pressures (1-10bar) and for photon energies between 5.4 and 60.0 keV, being possible to establish a linear match between the intrinsic position resolution and the inverse of the gas pressure in that energy range. In order to evaluate the quality of the method here described, a comparison between the available experimental data and the calculated one in this work, is done and discussed. In the majority of the cases, a strong agreement is observed

Primavera: arroz precoce 'agulhinha' para os cerrados de Rondonia.

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Simulation of gain stability of THGEM gas-avalanche particle detectors

Charging-up processes affecting gain stability in Thick Gas Electron Multipliers (THGEM) were studied with a dedicated simulation toolkit. Integrated with Garfield++, it provides an effective platform for systematic phenomenological studies of charging-up processes in MPGD detectors. We describe the simulation tool and the fine-tuning of the step-size required for the algorithm convergence, in relation to physical parameters. Simulation results of gain stability over time in THGEM detectors are presented, exploring the role of electrode-thickness and applied voltage on its evolution. The results show that the total amount of irradiated charge through electrode's hole needed for reaching gain stabilization is in the range of tens to hundreds of pC, depending on the detector geometry and operational voltage. These results are in agreement with experimental observations presented previously

Influencia de doses e volumes de aplicação na eficácia do glifosato no controle de plantas daninhas em seringal em formação.

Os objetivos deste trabalho foram avaliar a viabilidade da aplicação de glifosato em pos-emergencia no controle de ervas em seringueira em formação e determinar o efeito de doses de herbicidas e volume de calda aplicados com aparelho rotativo que produz goticulas de diametro controlado (CDA), em ultra baixo e baixo volume, comparado com aparelho tradicional, em medio volume de calda.bitstream/item/67392/1/CPAF-RO-DOCUMENTOS-30-INFLUENCIA-DE-DOSES-E-VOLUMES-DE-APLICACAO-NA-EFICACIA-DO-GLIFOSATO-NO-CONT.pd

Spherical f-Tilings by Two Noncongruent Classes of Isosceles Triangles

The study of spherical dihedral f-tilings when the prototiles are twononcongruent isosceles triangles was started in two previous papers. Here,we complete the classication, characterizing the f-tilings that satisfy theremaining case of adjacency. As it will be shown, this class is composed bytwo three-parameter families denoted by An;m; and Bn;m; and a relatedfour-parameter family denoted by Bp;q;p′;q′, where p > p′ 0; q′> q 0;two isolated tilings denoted by P and Q; and six distinct discrete familiesdenoted by J k;Lk; Mk;Nk(k 3); and Fk;Kk with k 4