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39th International symposium on Application of Computers and Operations Research in the Mineral Industry, APCOM 2019

作者： Araújo, C.P. Bassani, M.A.A. Costa, J.F.C.L. PPGE3M-Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul Porto AlegreRio Grande do Sul Brazil

ISBN: (纸本)9780367336042

To integrate the multiple variables, traditional methodologies suggest modelling the cross variograms and co-simulation using the Linear Model of Coregionalization (LMC), that is difficult task. This framework combines two approaches: Bayesian Updating and Sequential Gaussian Simulation considering all information regarding the relationship of the multiple variables without modelling the LMC. Firstly, at each soft data location, hard and soft data were incorporated using Bayesian Updating, which considers multivariate correlations between variables, to build a conditional distribution. Secondly, n-possible values are drawn from these conditional distributions and imputed as hard data. Next, Sequential Gaussian Simulation was performed to complete all the grid nodes using the original and pre-viously simulated hard data. The simulated models were compared with the models obtained by Sequential Gaussian Simulation (SGS) using only the original hard data. The results show the soft data addition improve the accuracy of the models once an appropriate methodology is used to incorporate them. © 2019 Taylor & Francis Group, London.

关键词： Gaussian distribution

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Influence of drilling spacing on the mineral resources uncertainty 39th

Influence of drilling spacing on the mineral resources uncer...

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39th International symposium on Application of Computers and Operations Research in the Mineral Industry, APCOM 2019

作者： Silva, C.J.E. Bassani, M.A.A. Costa, J.F.C.L. PPGE3M-Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul Porto AlegreRio Grande do Sul Brazil

ISBN: (纸本)9780367336042

Rock cores from drilling works in mineral research activities are the main ore modeling information and consume most of the budget. Data spacing should be optimized to reduce uncertainties in the geologic model and mineral resource inventory. This paper investigates how the uncertainty of the mineral resources is influenced by distinct data spacings through a case study on a bauxite mineralization in Brazilian Amazon plateau. The results showed that the uncertainty of the mineral resource decreases as the data spacing decreases. Depending on an acceptable uncertainty level, wider data spacings may be selected. This optimal drilling data spacing may be defined using the uncertainty in the mineral resource estimation, which is demonstrated in this case study. © 2019 Taylor & Francis Group, London.

关键词： Budget control

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Progressive fatigue damage modeling of composite curved structures used in offloading hoses 17

Progressive fatigue damage modeling of composite curved stru...

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17th European Conference on Composite Materials, ECCM 2016

作者： Tonatto, Maikson L. P. Forte, Maria M. C. Tita, Volnei Amico, Sandro C. Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul Porto AlegreRS Brazil Department of Aeronautical Engineering University of São Paulo São CarlosSP Brazil

ISBN: (纸本)9783000533877

Carbon fiber reinforced plastics (CFRP) have been used for manufacturing curved structures, which are applied in several equipment due to its high specific stiffness and strength. Recently, improvements in pultrusion and filament winding process allow the use of curved profile to manufacture coil and rings in equipment such as offloading hoses. In this research, a progressive fatigue damage modeling is proposed in order to simulate the fatigue behavior of unidirectional curved structure made of carbon fiber composite materials. In fact, a three-dimensional, non-linear, finite element model considering a central section of the hose was developed to simulate curved composites like coils and rings. A radial compressive displacement was applied in opposite direction to the fixed region. Kinetic theory of fracture (KTF) was used into the model to simulate the progressive fatigue damage. The failure analysis was carried out using the Multi-Continuum Theory (MTC). Using the proposed procedure, coils and rings fatigue life could be estimated. Therefore, this progressive fatigue damage modeling is an effective tool to predict failure in unidirectional curved composite structures used in offloading hose under fatigue. © 2016, European Conference on Composite Materials, ECCM. All rights reserved.

关键词： Finite element method

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Surface treatment of Kevlar® polyaramid fibers with imidazolium-based ionic liquids 11

Surface treatment of Kevlar® polyaramid fibers with imidazo...

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11th Annual TechConnect World Innovation Conference and Expo, Held Jointly with the 20th Annual Nanotech Conference and Expo, and the 2017 National SBIR/STTR Conference

作者： Moraes, C. Schrekker, H.S. Amico, S.C. Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul Porto Alegre Brazil Laboratory of Technological Processes and Catalysis Institute of Chemistry Federal University of Rio Grande do Sul Porto Alegre Brazil

ISBN: (纸本)9780997511789

Polyaramid fibers have excellent mechanical properties, such as high tensile strength-to-weight ratio and high thermal stability, but its applicability as reinforcement for composite materials is limited due to its high crystallinity and inert and smooth surface. In this work, an imidazolium-based ionic liquid (l-Butyl-3-methylimidazolium chloride) was used to treat Kevlar polyaramid fibers with the aim of improving Kevlar and epoxy resin interaction. The fibers were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM). Tensile strength tests were carried out to verify loss of mechanical properties caused by the treatment. Contact angle measurements and pull-out tests verified an improvement of the wettability and adhesion between the fibers and epoxy resin. The interfacial shear strength (IFSS) was improved by 37% and the contact angle was decreased from 35° to 22.

关键词： Epoxy resins

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Experimental analysis of jet slurry erosion on martensitic stainless steel 9

Experimental analysis of jet slurry erosion on martensitic s...

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9th International Scientific Conference on Research and Development of Mechanical Elements and Systems, IRMES 2019

作者： Santacruz, G. Takimi, A.S. Vannucchide Camargo, F. Bergmann, C.P. Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande Do Sul-UFRGS Osvaldo Aranha 99 Porto AlegreRS 90035-190 Brazil Department of Industrial Engineering University of Bologna Viale del Risorgimento 2 Bologna40136 Italy

Due to their enhanced tribological properties that contribute to an increased useful life of components, martensitic stainless steels are an excellent option for industrial applications such as hydroelectric, petrochemical, civil construction and mineral processing plants. In the present investigation, the erosive wear of AISI 410 martensitic stainless steel is evaluated after thermal treatment by quenching and tempering by mass loss, under erosive attack at 30° and 90° incidence angles, using a self-made jet slurry erosion equipment controlling parameters such as speed, volume of fluid, temperature and concentration of erosive particles of erodent. The characterization of the eroded samples was carried out in terms of the microstructure (SEM) and microhardness as well as the particle size distribution (LG) and morphology of the erodent. It was possible to establish the relationship between the slurry erosive wear and the physical properties inherent of stainless steel for this particular experimental configuration, concluding that the steel presents better resistance to jet slurry erosion wear when compared to austenitic steel commonly used in the industry. © Published under licence by IOP Publishing Ltd.

关键词： Erosion

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The Effect of Adding Ni and Sn to Pd Catalysts on the Direct Ethanol Fuel Cell Performance

The Effect of Adding Ni and Sn to Pd Catalysts on the Direct...

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2014 International Conference on Energy, Environment and Materials Engineering(EEME 2014)

作者： A.M.SHEIKH E.L.SILVA P.S.CORREA T.L.MENEZES C.F.MALFATTI Department of Mechanical Engineering South Valley University Corrosion Research Laboratory (LAPEC) Post-graduation Program in MiningMetallurgical and Materials Engineering Faculdade da Serra Gaúcha – FSG

Direct ethanol fuel cells DEFCs can convert chemical energy from ethanol electrooxidation directly to *** significant challenge for DEFC is the need for highly active surface catalysts for ethanol oxidation reaction *** this work,the impregnation-reduction method is used to synthesize binary Pd Ni and Pd Sn catalysts supported on functionalized carbon（Vulcan XC-72） with HNO to accelerate the EOR in alkaline electrolyte.X-ray diffraction XRD,cyclic voltammetry CV,and chronoamperometry CA tests were undertaken to characterize the structure and to evaluate the electrochemical performance of different *** was observed that Pd-Sn catalyst has achieved good alloying results enhancing the EOR activity;however the addition of Ni to Pd was even higher though synthesizing Pd and Ni has not proved strong alloying,and the best results were observed for the PdNi/C catalyst.

关键词： DEFC Ethanol oxidation Alkaline medium Pd catalyst

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Dual Synergetic Approach for Targeting Dysfunctional Cells Based on Rare-Earth-Doped Forsterite Nanoparticles

SSRN

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SSRN 2024年

作者： Zampiva, Rúbia Young Sun Kaufmann, Claudir Gabriel Viana, Altevir Rossato Rhoden, Cristiano Rodrigo Bohn Krause, Luciana Maria Fontanari Mortari, Sergio Roberto Rossi, Marco Bergmann, Carlos Pérez Alves, Annelise Kopp Jacinto, Carlos Brazil Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul-UFRGS RS Porto Alegre90035-190 Brazil RS Santa Maria Brazil Group of Cell Culture Bioscience Laboratory Franciscan University -UFN RS Santa Maria97010-032 Brazil Universidade Federal de Alagoas Brazil Department of Basic and Applied Sciences for Engineering University of Rome Sapienza RM Rome00185 Italy

In recent years, forsterite (Fo, Mg₂SiO₄) has emerged as a promising biomaterial for bone tissue engineering scaffolds, demonstrating efficacy in inhibiting the growth of clinical bacterial isolates. Additionally, rare-earth (RE) doped Fo exhibits excitation properties that match the near-infrared (NIR) biological transparency window (700-1800 nm), facilitating deep penetration into biological tissues. Despite these advantageous properties, the literature lacks data on the toxicity of RE-doped forsterite and its effects on damaged or dysfunctional cells, such as cancer cells. This study presents, for the first time, toxicity analyses of RE-doped forsterite nanoparticles (NPs) in cultures of healthy and tumor skin cells. Specifically, forsterite doped with Er³⁺, Yb³⁺, and a combination of Er³⁺/Yb³⁺, produced via reverse strike coprecipitation (RSC), was employed in cytotoxicity assays. The influence of solution pH on the toxicity response was also investigated. The results indicated that all NPs exhibited biocompatibility with keratinocytes, while melanoma cells showed increased cell death. Photoluminescence (PL) analyses revealed that Fo:Yb displayed enhanced blue emission under 980 nm excitation, whereas Fo:Er/Yb exhibited green and red emissions. The study proposes that the combination of the alkalinization effect of forsterite with the upconversion (UC) photoactivity of the NPs could serve as a dual-attack system for in situ oncological treatment. © 2024, The Authors. All rights reserved.

关键词： Nanoparticles

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Synthesis of cobalt ferrite (CoFe2O4) by combustion with different concentrations of glycine

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IOP Conference Series: Materials Science and Engineering 2019年第1期659卷

作者： C G Kaufmann Junior R Y S Zampiva A K Alves C P Bergmann L Giorgini Post-Graduation Program in Mining Metallurgy and Materials Engineering (PPGE3M) Federal University of Rio Grande do Sul Osvaldo Aranha 99 90035-190 Porto Alegre Brazil Post-Graduation Program in Production and Transport Engineering (PPGEP) Federal University of Rio Grande do Sul Osvaldo Aranha 99 90035-190 Porto Alegre Brazil Department of Industrial Chemistry 'Toso Montanari' University of Bologna Viale del Risorgimento 4 40136 Bologna Italy

Among the wide range of applications of Cobalt Ferrite (CoFe2O4), its usage for the manufacturing of modern electronic devices such as solar panels, capacitors and batteries has been studied' lately. Hence, solar-powered vehicles, which strongly rely their performance on energy efficient electronics, is a sector that could particularly benefit from enhanced applications of such material. In this work, the synthesis of Cobalt Ferrite was studied by means of Solution Combustion Synthesis (SCS) using iron nitrate nonahydrate and cobalt nitrate hexahydrate as precursors, and glycine as fuel. The nitrates were dissolved in distilled water and placed under stirring and heating for 5 minutes; when the temperature reached 60°C, glycine was added; after complete homogenization, the solution was placed in an electric oven (400°C) until complete combustion (approximately 15 minutes). Three syntheses were carried out using different concentrations of fuel: lean, stoichiometric and rich. The product crystallite size and composition were investigated in order to determine the influence of the fuel concentration on the structure of the produced cobalt ferrite.

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Experimental analysis of jet slurry erosion on martensitic stainless steel

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IOP Conference Series: Materials Science and Engineering 2019年第1期659卷

作者： G Santacruz AS Takimi F Vannucchide Camargo CP Bergmann Post-Graduation Program in Mining Metallurgical and Materials Engineering Federal University of Rio Grande do Sul - UFRGS Osvaldo Aranha 99 Porto Alegre RS 90035-190 Brazil Department of Industrial Engineering University of Bologna Viale del Risorgimento 2 40136 Bologna Italy

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Solution combustion synthesis of Mo-Fe/MgO: Influence of the fuel composition on the production of doped catalyst nanopowder

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IOP Conference Series: Materials Science and Engineering 2019年第1期659卷

作者： R Y S Zampiva C P Bergmann A K Alves L Giorgini Post-Graduation Program in Mining Metallurgy and Materials Engineering (PPGE3M) Federal University of Rio Grande do Sul Osvaldo Aranha 99 90035-190 Porto Alegre Brazil Department of Industrial Chemistry 'Toso Montanari' University of Bologna Viale del Risorgimento 4 40136 Bologna Italy

Among the techniques for producing oxide catalysts, the solution combustion synthesis (SCS) has been widely used to produce high-quality nanostructured powders at low-cost. Through SCS, due to the high exothermic energy liberated by the reaction between the transition metal nitrate and the fuel, it is possible to homogeneously incorporate dopant ions into the catalyst. Besides, SCS allows the production of nanopowders with sizes in the decimal scale, which is extremely important for powdered catalysts. The smaller the particle is, the larger the surface area is. Based on these possibilities, the aim of this work is to produce Fe-Mo/MgO nanopowders by SCS. The influence of concentration and composition of the fuels glycine and polyethylene glycol (PEG) on the final product were investigated. The morphology and the physicochemical properties were characterized by X-ray diffraction (XRD), electron microscopy (SEM), granulometry and surface area analysis. The results indicated high crystallinity for the samples produced with PEG and a wide variation on the nanoparticles sizes depending on the fuel properties.

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