Abstract In Brazil, 65% of the electric power production comes from hydroelectric power plants (HPPs). In some cases, these power plants divert the course of rivers, resulting in regions impacted by the absence of water, which are known as reduced fow sections (RFS). These sections are regulated by legislation and aim to maintain the minimum fow necessary to preserve the fauna, flora, fish, and human consumption in the region. Depending on the time of year, this minimum flow, also known as ecological flow (residual flow), can reach significant values, resulting in the interruption of power generation in these HPPs. This article presents a study case of two hydroelectric power plants located in different Brazilian states. The objective of this study is to explore the feasibility of implementing auxiliary generator groups that can operate uninterruptedly at different drop heights while ensuring the preservation of residual flow during low flow periods or taking advantage of the overflow flow by spillways during high flow periods. This auxiliary system would use the same set of structures and transmission systems as the main power plant, minimizing environmental impacts and implementation costs, allowing this solution to be implemented in HPPs that face this type of problem in Brazil. The results obtained indicate that HPPs with larger reservoirs have a greater ability to maintain residual flows with minimal generation loss and that run-of-the-river power plants are the most impacted by the maintenance of residual flow. Brazil 65 . (HPPs) cases rivers water RFS. RFS (RFS) fauna flora fish region year , flow) values states plant costs runoftheriver run river 6 (HPPs (RFS

Abstract In the county of Pedra Lavrada - PB, various mineral occurrences of pegmatite are observed with prominence at Alto Dois Irmãos - PB, where quartz, feldspar and mica are mined. The understanding of mineral constituents is fundamental to define their industrial employment and to implement improvements in the beneficiation process. The proposal of this research is the detailed characterization and proof of that part of the ore (quartz) considered waste, presenting low poisoning (Fe2O3) and high silica (SiO2) content, to enable its industrial use. Besides that, to minimize the environmental impact through the reuse of this waste, and to determine the correct utilization of the milling equipment. For the pegmatite characterization, done were density determination tests, mineralogical identification by X-ray diffraction (XRD), chemical analysis by fluorescents X-rays and morphological analysis by scanning electron microscopy (SEM/EDS). Then tests were done for the Work Index (WI) calculous and consequently the empirical determination of the dimensions (LxD) of the pebble mill. The sterile presented a medium density of 2.66g/cm³, majority chemical composition of silicon and oxygen and quartz as the main mineralogical stage, indicating that this material has high purity. The. The Work Index (WI) was 15.9 kwh/t showing that this material can be considered resistant to breaking in the grinding process. The necessary energy to the milling was defined in 11.52 kwh/st, that corresponds to 57.28 HP. This power allowed the mill selection with diammeter and length of 1.83m, that provides the production maximization and the energy saving. PB mined process (quartz waste Fe2O3 FeO Fe O (Fe2O3 SiO2 SiO (SiO2 content use equipment Xray X ray XRD, XRD , (XRD) Xrays rays SEM/EDS. SEMEDS SEM/EDS . SEM EDS (SEM/EDS) WI (WI LxD (LxD 266gcm³ gcm 2 66g cm³ g cm 2.66g/cm³ stage purity 159 15 9 15. kwht kwh t 1152 11 52 11.5 kwhst st kwh/st 5728 57 28 57.2 HP 183m m 1 83m 1.83m saving Fe2O (Fe2O (SiO (XRD (SEM/EDS 266gcm 2.66g/cm 115 5 11. 572 57.

Abstract Nowadays, despite the implementation of new wind farms in Brazil, it still is difficult to form partnerships with companies in the sector, which significantly contributes to the gap in information provided by national literature and the lack of knowledge about the mechanical behavior of wind turbines subjected to transient wind effects. Therefore, through a Research and Development Project to optimize and improve modeling in wind systems, the Brazilian electric power company Eletrobras Furnas aims to facilitate the construction of smaller wind turbines to supply energy to regions far from the Brazilian coast that do not have high generation potential due to the incidence of low-speed winds. Two relevant aspects directly linked to the performance of this kind of structures are: (i) determining their natural frequency and (ii) ensuring that this frequency does not coincide with any external vibration frequency that the structure may experience in its lifetime. Wind turbines are complex systems with many degrees of freedom and their own frequencies associated with the respective mode shapes in which they naturally vibrate. These frequencies are inversely related to the mass and directly related to the stiffness of the structure. Thus, through numerical modeling using the Finite Element Method, the present article aims to list some of the main factors that can affect the prediction of the natural frequency of a real-scale wind turbine prototype and to evaluate its dynamic behavior, considering its rotor revolution frequency, its blade passing frequency and the wind characteristics of its operating area. Nowadays Brazil sector effects Therefore lowspeed low speed winds i (i ii (ii lifetime vibrate Thus Method realscale real scale area

Abstract Cornstarch is one of the most used depressants in mineral flotation operations. However, corn is a costly input for the Brazilian mineral industry, since its main destination is to serve the animal and human food market and exports. In this study, sorghum and millet, two cheaper starch sources, were tested in order to reduce the mining dependence on corn. A simplex lattice design mixture {3,4} was used to evaluate the best proportion of corn, millet, and sorghum flours to be used as a pyrochlore depressant in relation to the industrially adopted cornstarch (Stargill 6172 supplied by Cargill). Flotation tests were carried out on a bench scale Denver flotation cell. All tests were performed in triplicate in a single rougher stage. The results found suggest that sorghum flour was a stronger pyrochlore depressant compared to corn and millet flours, with an average Nb2O5 content of 1.72 ± 0.05% and recovery of 80.75 ± 4.10%. These values were close to the ones found with Stargill 6172 (1.32 ± 0.02 and 80.95 ± 1.13%, Nb2O5 content and recovery, respectively), the industrially adopted depressant. The marked price and the easiness in the production of the flour in relation to the extraction of starches makes the sorghum flour a potential pyrochlore depressant, replacing the industrially used cornstarch. operations However industry exports study sources 3,4 34 3 4 {3,4 617 Cargill. Cargill . Cargill) cell stage NbO Nb O Nb2O 172 1 72 1.7 005 0 05 0.05 8075 80 75 80.7 410 10 4.10% 1.32 132 32 (1.3 002 02 0.0 8095 95 80.9 113 13 1.13% respectively, respectively , respectively) 3, {3, 61 17 7 1. 00 807 8 80. 41 4.10 1.3 (1. 0. 809 9 11 1.13 {3 6 4.1 (1 1.1 { 4. (

Abstract A kitagohaite grain, measuring approximately 1.0 mm, was retrieved from an alluvial gold gravity concentrate from the southeastern Quadrilátero Ferrífero (QFe), Mariana, Brazil. The grain exhibits a cubic structure, whitish-steel-gray, and has a metallic luster. It is composed of Wt. 94.42% Pt and 5.56% Cu (n=9), yielding the empirical formula Pt6.78Cu1.22. This groundbreaking discovery marks the first documented occurrence of kitagohaite in South America. This hydrothermal deposition of kitagohaite indicates that its mineralization is constrained to temperatures <500º C, as inferred by the stability of synthetic Pt7Cu. 10 1 0 1. mm QFe, QFe , (QFe) Mariana Brazil structure whitishsteelgray, whitishsteelgray whitish steel gray, gray whitish-steel-gray luster Wt 9442 94 42 94.42 556 5 56 5.56 n=9, n9 n n=9 9 (n=9) Pt678Cu122 PtCu Pt6 78Cu1 22 Pt6.78Cu1.22 America 500º º C Pt7Cu (QFe 944 4 94.4 55 5.5 n= (n=9 Pt678Cu12 78Cu 2 Pt6.78Cu1.2 94. 5. (n= Pt678Cu1 Pt6.78Cu1. (n Pt678Cu Pt6.78Cu1 Pt6.78Cu

Abstract A continuous increase in levels of atmospheric pollution and emission restrictions has forced scientists and engineers to adopt new strategies to improve and develop internal combustion engines. One strategy is based on the development of new simulation methodologies using computational fluid dynamic (CFD) techniques, proposed in the present article. In this study,the dynamic loop methodology with ANSYS Fluent code is proposed to perform the numerical simulation ofa four-stroke spark ignition engine. The complexity of the real case was first simplified with three-dimensional CAD geometry, which was then discretized in ANSYS Meshing, whereby a hybrid mesh was created using prismatic and tetrahedral elements. Simulations for in-cylinder analyses were performed in cold flow and employing common flow parameters, such as swirl and tumble. The mesh quality results were classified as good or excellent, being higher than 0.79 for orthogonal quality criteria and lower than 0.36 for skewness criteria. Turbulent effects were introduced concerning the opening and closing of the valves. It was found that the turbulence increases during the intake stroke up to 90°, and during the power stroke, wherein the of the piston bowl, had a great contributionthat can be seen from the swirl and tumble profile for the engine cycle. In the case of the turbulence intensity, a sharp increase was registered during the admission step up to 90°, at which point the turbulence intensity was 4.0. It canbe concluded that this is an innovative approach, capable of simulating the engine motion profile in cold flow. engines CFD (CFD techniques article studythe study fourstroke four threedimensional three dimensional geometry Meshing elements incylinder cylinder parameters excellent 079 0 79 0.7 036 36 0.3 valves 90 90° bowl cycle 40 4 4.0 approach 07 7 0. 03 3 9 4.

Abstract The flotation mechanism of galena with xanthate as the collector is generally explained based on the mixed potential of the pulp, in which an anodic electron transfer reaction from the collector to the mineral is combined with an O2 cathodic reduction. Sodium sulphide, often used as a mineral activator, strongly influences the pulp's mixed potential, and depending on the dosage applied, it can become a galena depressor reagent. In this way, the current study assesses galena flotability in the absence of collector, as well as in the presence of the collector potassium amyl xanthate (PAX) and sodium sulphide. The effect of an extremely cathodic potential was also studied through the addition of hydrogen peroxide. In addition, the effect of different stages in the oxidation of the galena surface on the flotability was investigated. Moreover, the zeta potential was measured and contact angle (wettability) tests were carried out. The contact angle measurements were taken for a distilled water, PAX solution and for a mixture of PAX and sodium sulphide solution on the oxidized and non-oxidized surface of galena. All the results showed that galena could be floated in all the PAX concentrations tested. It was observed that a moderate oxidation in the galena surface may contribute to an improvement of its flotation with PAX. However, extremely anodic and cathodic potentials cause flotability close to zero. The zeta potential results showed that sodium sulphide affected the interaction between PAX and galena. The measurements of the contact angle corroborated the results obtained in the microflotation tests. pulp O reduction activator pulps s applied reagent way (PAX peroxide investigated Moreover wettability (wettability out water nonoxidized non tested However zero

Abstract Recent events involving iron ore tailings dam collapses have emphasized the need for developing alternative ways of depositing tailings. This study aims to evaluate the effects of using three hydroxamates and a sulfosuccinamate as collectors in the direct flotation of iron ore tailings, using a bench flotation. The best result obtained on bench flotation was tested in a pneumatic cell. The sample used in this study (10.8% of Fe) consists of quartz and hematite. The Aero® 6494 Promoter hydroxamate showed the highest selectivity among the analyzed reagents, reaching 64.31% of Fe in the final product of the test with the < 150 µm sample. The possibility of using these reagents as constituents of a mixed collector with dodecylamine was also investigated. In this case, the Aero® 845 Promoter sulfosuccinamate yielded the best results, with 62.84% of Fe and 59.01% of metallurgical recovery of Fe. The synergistic effect between the two reagents might be explained by the stability of the monolayer formed by the intercalation of the ions from the dodecylamine and the Aero® 845 Promoter, which reduces the electrostatic repulsion between ions of the same species This mixed collector was tested in a pneumatic cell. However, it had a lower performance in terms of Fe metallurgical recovery than in a bench-scale cell test, mainly for the finest particles, due to the greater control of the process’s variables in the bench cell. 10.8% 108 10 8 (10.8 hematite Aero 649 6431 64 31 64.31 15 investigated case 84 results 6284 62 62.84 5901 59 01 59.01 However benchscale scale particles processs process s 10.8 1 (10. 643 6 3 64.3 628 62.8 590 5 0 59.0 10. (10 64. 62. 59. (1 (

Abstract This article presents a formulation for the optimization problem that minimizes the CO2 emission of pile caps with variations of geometry and pile position. The problem is defined by the design variables: concrete pile cap dimensions, rebar ratio, concrete compressive strength, the number of piles, the diameter, and length. The environmental impact was chosen as the objective function, taking CO2 emission as the main parameter. The design procedure was based on the ABNT NBR 6118:2014 (2014), and by the formulation proposed by Blévot & Frémy (1967). Also, the soil structure interaction between the cap and the piles was considered in the optimization problem. The problem was implemented using MATLAB (2016) and solved via a Genetic Algorithm native to the program. Results obtained from numerical examples were compared with structural designs solutions located in the Grande Vitória metropolitan area, Espírito Santo, Brazil and validated with a commercial software. The analyses indicate that design optimizations of pile caps considering the compressive strength of concrete, the diameter and length of piles and the optimal geometry of the pile caps may lead to significant reductions of material consumption, and consequently, a reduction of environmental impacts. CO position variables dimensions ratio function parameter 61182014 6118 2014 6118:201 2014, , (2014) 1967. 1967 . (1967) Also 2016 (2016 program area Santo software consumption consequently impacts 6118201 611 201 6118:20 (2014 196 (1967 (201 611820 61 20 6118:2 19 (196 (20 61182 6 2 6118: 1 (19 (2 (1 (

Abstract The transport capacity of the slurry pipelines is related to the internal roughness of the pipe. Thus, the application of corrosion protection methods is of fundamental importance, both in the operational phase and in times of temporary shutdown. In addition, corrosion also affects the service life of the duct. The studied pipeline was hibernated with nitrogen using the ABNT NBR 15280-2 standard as a reference and remained hibernated for 3.5 years. Chemical, mineralogical, and microstructural analyses were carried out on samples of materials removed from the pipeline interior during the hibernation period. The most striking phase found was magnetite, with botrioidal morphology, formed by the oxidation of steel in the pipeline. After reactivation, the pipeline was inspected by smart pigs with ultrasound and MFL technologies. It was found that the corroded regions are more concentrated in the initial kilometers of the sections, where important depths of corrosion were also observed, as well as higher rates of corrosion and erosion, which show the influence of the operational phase in the development of the pipeline corrosive process and wear. Thus, the application of the nitrogen hibernation process in long-distance pipelines proved to be feasible for long periods of time. However, improvements are suggested in this article to make the process more robust. pipe Thus importance shutdown addition duct 152802 15280 2 15280- 35 3 5 3. years Chemical mineralogical period magnetite morphology reactivation technologies sections observed erosion wear longdistance distance time However robust 1528 152 15 1

Abstract Process simulations can be used to improve grinding circuit performance, which efficiently reduces operating costs. The population balance model (PBM) is widely accepted for grinding modeling because it can reproduce breakage events in tumbling mills, as described by Austin et al. (1984). In this study, a pseudo-dynamic model is introduced, integrating the PBM with the Monte Carlo Method to stochastically simulate variables in an industrial grinding circuit. This integrated approach enabled circuit simulations over a period of 2 hours, representing the operational variables as seen in historical data. Model validation showed a correlation of 0.74 in the product size distribution when comparing simulated outcomes with the original population. performance costs (PBM mills al 1984. 1984 . (1984) study pseudodynamic pseudo dynamic introduced hours data 074 0 74 0.7 198 (1984 07 7 0. 19 (198 1 (19 (1 (

Abstract The modeling of mineral deposits has been improved over the years with the incorporation of mineralogical and metallurgical information obtained from drilling samples that make up the pillars for the construction of resource models. However, sampling data is being made available in large quantities, causing current databases to grow exponentially. The use of machine learning (ML) algorithms has been applied to deal with multidimensional data problems. Principal component analysis (PCA) is a multivariate analysis (MA) technique whose aim is to reduce the dimension of multivariate data. Studies show that results obtained with the reduction of variables were satisfactory in different areas of activity. The purpose of this article is to test variable selection criteria using PCA for geometallurgical data and to check the feasibility of the technique for simplifying variable types and defining typological domains. models However quantities exponentially ML (ML problems (PCA MA (MA activity domains

Abstract When processed conventionally, aluminum-bronze alloys with high mechanical strength require machining after the raw state of fusion, and the waste (chips), if not reused, can cause problems for the environment and costs for the company. Therefore, this article proposes an alternative for recycling aluminum bronze through the new route via Powder Metallurgy (PM), analyzing the resulting microstructure. This study compares the microstructures of the aluminum bronze derived from extraction (the samples received - SR) and the state after the powder metallurgy (PM) process with the addition of vanadium carbides (VC). The study also analyzes the distribution of VC in the microstructure of the PM composite as well as the influence of the TQ30 heat treatment on this composite. For the PM process, aluminum alloy and bronze chips were ground together with vanadium carbide (VC) in a high-energy mill for 50 hours. The powders obtained were pressed uniaxially (400 MPa) to achieve good compaction. The samples were then sintered (900°C/lh), water quenched (900°C/2h), and subjected to treatment according to the TQ30 standard, which, in addition to the previous treatments, also includes tempering at 500°C for 2 hours (ASTM B150/B150M-12 standard). The microstructure observed in the SR samples was martensitic (in needles), with secondary phases dispersed in the matrix. On the other hand, the microstructure of the PM samples showed equiaxed grains of the alpha phase (a), as well as the secondary phases kapa (k) and beta line (β1), in contrast to the needle-shaped microstructure of the conventional melting process. conventionally aluminumbronze fusion chips, , (chips) reused company Therefore PM, (PM VC. . TQ TQ3 (VC highenergy energy 5 400 (40 MPa compaction 900°C/lh, 900Clh Clh 900°C/lh 900 C lh (900°C/lh) 900°C/2h, 900C2h Ch 900°C/2h 2h h (900°C/2h) standard which treatments 500C 500 ASTM B150/B150M12 B150B150M12 BBM B150/B150M 12 B150 B150M B M B150/B150M-1 standard. standard) needles, needles needles) matrix hand a, (a) k (k β1, β1 β (β1) needleshaped needle shaped (chips 40 (4 90 (900°C/lh (900°C/2h B150M12 B150/B150M1 B150B150M1 B150B150M 1 B15 BM B150/B150M- (a (β1 4 ( 9 B150M1 B1 (β

Abstract Federal higher education institutions in Brazil have particularities in terms of construction, geographical location, use of buildings, organizational structures and allocation of budgetary resources. These characteristics make managing the Fire Protection System a significant challenge, requiring an even higher level of attention and commitment. This article aims to present data describing the current context of Fire Protection and Fire Fighting System management at Federal higher education institutions in Brazil (Federal universities and institutes). The data collection was a survey, in which 87 employees, representing 69 institutions, occupying the positions of Occupational Safety Engineer or Technician took part. Among the results, the following stand out: 51% of the institutions do not have a Fire Protection System Management Plan and 32% are in the process of creating one. All institutions inspect and maintain fire extinguishers; only a minority monitor other equipment. Operational routines are weakened by a lack of management (35%), financial resources (31%) and technical staff to carry out the service (24%). Only 9% of the institutions have a Fire Department Inspection Certificate for all their buildings and 5% have an active fire department in all their buildings. Only 9% of institutions have a Fire Department Inspection Certificate for all buildings and 5% have an active fire department in all buildings. The management of the Fire Protection System in Federal higher education institutions in Brazil faces significant challenges, including a lack of management plans, insufficient control of devices and limited resources, resulting in low compliance with fire safety regulations. construction location challenge commitment institutes. institutes . institutes) survey 8 employees 6 part results 51 32 one extinguishers equipment 35%, 35 35% , (35%) 31% 31 (31% 24%. 24 24% (24%) 9 5 challenges plans regulations 3 (35% (31 2 (24% (35 (3 (24 ( (2