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Item Valuation of losses and damages resulting from the Fundão's dam failure : an emergy perspective.(2022) Scarpelin, Juliano; Agostinho, Feni Dalano Roosevelt; Almeida, Cecília Maria Villas Bôas de; Giannetti, Biagio Fernando; Dias, Lívia Cristina PintoIn 2015, the ‘Fundão’ dam’s failure in Brazil released 44 million m3 of tailings that traveled 670 km in the ‘Doce’ river watershed crossing 40 municipalities and two states until reaching the Atlantic Ocean. Since then, a public civil action (PCA) is responsible for litigation processes, and recently established a value of US$ 43.8 billion to repair losses and damages, a value that brings doubts about its accuracy in expressing the loses and damages of the disaster. This claims for alternative methods for its monetary quantification than the current tradicional economic ones. Among others biophysical approaches, the emergy accounting appears as a powerful tool due to its donor side perspective that objectively quantifies value and recognizes energy quality. This study aims to use emergy accounting as method to firstly identify and then quantify the impacts of ‘Fundão’ dam’s failure, considering exclusively the negative direct and immediate impacts. Three categories are considered to quantify loses and damages: (I) suppressed stocks in the mud passage and deposition areas (MPDA), (II) social disruption, and (III) changes in landscape. For all the three scenarios of turnover times (Tt), results show that about 98% of total emergy in the suppressed stocks are related to (II) and (III), while only 2% in average is related to (I). This discrepancy highlights the importance of accounting for (II) and (III) since they are often disregarded or not directly considered by traditional economic approaches. From a macroeconomic perspective, the highest total emergy-based dollars (emdollar, EmUS$) found for scenario #3 reached EmUS$ 149.18 billion, a value 3.4 times higher than the US$ 43.8 billion established by PCA. This higher value is equivalent to the annual emergy demanded by the Ecuador economy with 18 million inhabitants. Rather than providing an accurate monetary value for the ‘Fundão’ disaster repair, this study contributes for the advancement of discussions about using biophysical methods such as emergy accounting that allows tracking all numbers for objective verification as alternative to the traditional economic approaches in quantifying losses and damages of high proportion disasters.Item Susceptibility to liquefaction of iron ore tailings in upstream dams considering drainage conditions based on seismic piezocone tests.(2024) Costa, Giovani Cecatto Lopes Ribeiro da; Gomes, Guilherme José Cunha; Nierwinski, Helena PaulaOne of the critical challenges facing the mining sector is related to the prevention and mitigation of catastrophic incidents associated with its tailing dams. As mining tailings are very heterogeneous and field characterization is expensive and complex, geotechnical properties of these materials are largely unknown. The seismic cone penetration test (SCPTu) provides a field approach to estimate a large array of geotechnical information, including the liquefaction potential of tailing dams. Yet, the exploration of strain softening behaviors in geomaterials under undrained loading, utilizing the state parameter (ψ) inferred from SCPTu tests initially applied to soft soils, has been often used for mining tailings. This study is concerned with the implementation of a tailing classification system which uses the ratio between the small strain shear modulus and the cone tip resistance (G0/qt). A series of laboratory tests was executed, and three different methodologies were adopted to assess the effects of (partial) drainage conditions based on 531.26 m of SCPTu measurements conducted at three different upstream iron ore tailing dams in Brazil. Furthermore, the G0/qt ratio is integrated with ψ to assess the liquefaction tendencies of the investigated materials. The findings reveal the heterogeneous nature of the tailings, wherein indications of partial drainage are discernible across numerous records. Liquefaction analyses demonstrate that the tailings exhibit a contractive behavior in over 94% of the SCPTu data, confirming their susceptibility to flow liquefaction. Our findings are relevant for site characterization within iron ore tailing dams and other mining sites with similar geotechnical attributes.Item Recycled Kambara reactor slag powder as a sustainable stabilizer for clayey soils in road construction.(2024) Causado Mendoza, Luis Eduardo; Gomes, Guilherme José Cunha; Pires, Patrício José Moreira; Bridi, Lucas OliveiraSteel manufacturers around the world are looking for ways to produce higher quality, lower-sulfur steel. This requires an additional desulfurization step using the Kambara reactor (KR) during steel production. As a side effect, the Kambara reactor’s slag processing generates emissions that are captured and concentrated in dust collectors such as bag filters, reducing overall air pollution. While the use of KR slag has gained attention in the road material industry for improving pavement design performance, the reuse potential of KR slag powder (KRSP), collected by special bag filters, remains underexplored. This study investigates the chemical composition, physical properties, and mechanical characteristics of clayey soil mixed with KRSP. To assess the byproduct’s ability to stabilize this soil, laboratory experiments were conducted on raw materials and soil mixed with 3% and 5% KRSP. The results reveal that the specific gravity of KRSP (2.23 g/cm3) is lower than that of granulated KR slag. X-ray fluorescence analysis detected no iron (Fe) in its composition, and the percentage of calcium oxide (CaO) was below 40%. Portland cement (Ca(OH)2) was identified as the main mineral present through X-ray diffraction analysis, and brucite (Mg(OH)2) as the minor mineral. The addition of 3% and 5% KRSP to clayey soil resulted in a significant increase in California Bearing Ratio (CBR) values (from 13 to 42% and 41%, respectively) after only 4 days of curing. Unconfined compressive strength values obtained for the 3% and 5% KRSP mixtures were 1.25 MPa and 0.95 MPa, respectively, after 7 days of curing. Atterberg limits, particle size distribution, and expansion tests reinforced the results, showing compliance with the requirements for first-class subbase materials. This finding demonstrates that KR desulfurization dust collector powder has the potential to be used as an environmentally friendly stabilizing agent, contributing to improved waste management in the steel industry.Item Polymeric delivery systems as a potential vaccine against Visceral Leishmaniasis : formulation development and immunogenicity.(2023) Silva, João Guilherme Lino da; Gonçalves, Ana Alice Maia; Oliveira, Liliam Teixeira; Garcia, Giani Martins; Batista, Maurício Azevedo; Mendonça, Ludmila Zanandreis de; Viana, Kelvinson Fernandes; Sant’Ana, Rita de Cássia Oliveira; Melo Júnior, Otoni Alves de Oliveira; Lemos, Denise Silveira; Dutra, Walderez Ornelas; Martins-Filho, Olindo Assis; Galdino, Alexsandro Sobreira; Moura, Sandra Aparecida Lima de; Mosqueira, Vanessa Carla Furtado; Giunchetti, Rodolfo Cordeiro; Garcia 3 , , Giani MartinsRecent studies suggest that the association of antigens in microparticles increases the anti-Leishmania vaccine immunogenicity. This study aims to investigate the in situ effect of the adjuvant performance consisting of chitosan-coated poly(D,L-lactic) acid submicrometric particles (SMP) and analyze the inflammatory profile and toxicity. Two formulations were selected, SMP1, containing poly(D,L-lactide) (PLA) 1% wt/v and chitosan 1% wt/v; and SMP2, containing PLA 5% wt/v and chitosan 5% wt/v. After a single dose of the unloaded SMP1 or SMP2 in mice, the SMPs promoted cell recruitment without tissue damage. In addition, besides the myeloperoxidase (MPO) activity having demonstrated similar results among the analyzed groups, a progressive reduction in the levels of N-acetyl-β-D-glucosaminidase (NAG) until 72 h was observed for SMPs. While IL-6 levels were similar among all the analyzed groups along the kinetics, only the SMPs groups had detectable levels of TNF-α. Additionally, the Leishmania braziliensis antigen was encapsulated in SMPs (SMP1Ag and SMP2Ag), and mice were vaccinated with three doses. The immunogenicity analysis by flow cytometry demonstrated a reduction in NK (CD3−CD49+) cells in all the SMPs groups, in addition to impairment in the T cells subsets (CD3+CD4+) and CD3+CD8+) and B cells (CD19+) of the SMP2 group. The resulting data demonstrate that the chitosan-coated SMP formulations stimulate the early events of an innate immune response, suggesting their ability to increase the immunogenicity of co-administered Leishmania antigens.Item The influence of cartographic representation on landslide susceptibility models : empirical evidence from a Brazilian UNESCO world heritage site.(2024) Araujo Junior, Jefferson Alves; Barella, Cesar Falcão; Eiras, Cahio Guimarães Seabra; Montandon, Larissa Flávia; Fonseca, Alberto de Freitas CastroThe influence of cartographic representation of landslides on susceptibility models is well-known but often neglected by academic studies, which rarely explore its practical implications. This study aims to address this knowledge gap by evaluating the impact of different landslide sampling strategies on statistical models of landslide susceptibility in Ouro Preto, a UNESCO World Heritage Site located in South-eastern Brazil. The study’s main objective was to assess how different landslide sampling strategies affected statistical susceptibility models. It adopted an innovative methodological approach that categorized dependent variables between training and test subgroups, adopting both balanced and unbalanced divisions of dependent variables, and focusing on shallow and deep landslides. In addition, the study introduced a systematic and critical approach to cartographic representation, providing valuable insights for future research and practice on landslide susceptibility mapping. Eighteen models were produced using an inventory with 57 historical landslides mapped with an Unmanned Aerial Vehicle. The area and volume of these landslides were determined. Three divisions of dependent variables were adopted between training and test subgroups: one balanced division, with large and deep landslides in both subgroups, and two unbalanced divisions, with a predominance of large and deep landslides in the training subgroup or test subgroup. The construction of landslide susceptibility models employed the information value method, validated through success and prediction curves. The results show the significant influence of cartographic representation (point or polygon) on the quality of statistical models and the spatial distribution of susceptibility classes. The polygonal cartographic representation and balanced partition of dependent variables produced the best results. However, it is emphasized that this cartographic representation is not universally optimal in other contexts. The worst result was obtained using a point and random cartographic representation. Overall, findings indicate the need for more accurate landslide inventories and databases, possibly through standards and regulations.Item Implementação de uma topografia pré-ruptura na predição estatística bivariada de escorregamentos.(2023) Araújo, João Paulo de Carvalho; Barella, César Falcão; Zêzere, José Luís; Fernandes, Nelson FerreiraMovimentos gravitacionais de massa são fenômenos naturais que impactam a economia, a infraestrutura e a vida de milhares de pessoas. Na modelagem estatística, os Modelos Digitais do Terreno (MDTs) são frequentemente utilizados na identificação das cicatrizes de escorregamentos e na geração dos mapas temáticos causativos que podem ser analisados individualmente ou computados em conjunto para gerar o mapa final de susceptibilidade a escorregamentos. Contudo, quando obtidos após a ocorrência dos movimentos de massa, estes MDTs não mais representarão as características do terreno que favoreceram a ocorrência das instabilidades (topografia pós-falha). Ademais, o uso de assinaturas morfométricas arquetípicas de escorregamentos pretéritos em modelos estatísticos implica em erros conceituais relevantes. Uma possível solução para este problema é assumir que a morfometria pré-ruptura possa ser inferida pelas áreas adjacentes às cicatrizes que não foram perturbadas pelos escorregamentos. Este trabalho apresenta um método de reconstrução da topografia pré-ruptura a partir da nuvem de pontos de elevação do último retorno dos pulsos laser de um sensor LIDAR e faz uso do MDT pré-ruptura na modelagem de predição estatística bivariada (Pesos de Evidência) dos escorregamentos nas bacias do Quitite e Papagaio, na cidade do Rio de Janeiro. Sete modelos de susceptibilidade a escorregamentos foram produzidos pela combinação de oito fatores causativos. Cada mapa teve sua capacidade preditiva testada pelo cálculo da área abaixo da curva (AAC) de predição. O modelo final (AAC = 0,77) evidencia os controles topográficos e hidrológicos diretos e o controle litológico e estrutural indireto na deflagração dos escorregamentos. Os escorregamentos são condicionados, principalmente pelas encostas entre os ângulos de 26° e 52°, voltadas para as faces Norte, Nordeste e Noroeste, em forma côncava convergente e côncava divergente e com área de contribuição entre log101,8m2 e log104,1m2. Os resultados respeitam os principais pressupostos do modelo e proporcionam uma visão sintetizada e robusta das áreas susceptíveis a escorregamento, mesmo em um ambiente de grande complexidade geoambiental, como é o caso da área de estudo.Item The impacts of plastic waste from personal protective equipment used during the COVID-19 pandemic.(2023) Cubas, Anelise Leal Vieira; Moecke, Elisa Helena Siegel; Provin, Ana Paula; Dutra, Ana Regina Aguiar; Machado, Marina Medeiros; Gouveia, Isabel CristinaThe period from 2019 to 2022 has been defined by the COVID-19 pandemic, resulting in an unprecedented demand for and use of Personal Protective Equipment (PPE). However, the disposal of PPE without considering its environmental impact and proper waste management practices has become a growing concern. The increased demand for PPE during the pandemic and associated waste management practices have been analyzed. Additionally, the discussion around treating these residues and exploring more environmentally friendly alternatives, such as biodegradable or reusable PPE, is crucial. The extensive use of predominantly non-degradable plastics in PPE has led to their accumulation in landfills, with potential consequences for marine environments through the formation of microplastics. Therefore, this article seeks to establish a connection between these issues and the Sustainable Development Goals, emphasizing the importance of efficient management aligned with sustainable development objectives to address these emerging challenges and ensure a more sustainable future.Item Green propolis : a review of pharmaceutical patents with potential therapeutic applications.(2024) Batista, Marcos Adriano Carlos; Nolasco, Emanuelle Rodrigues; Moura, João Pedro Mendes; França, Robert Lucas Ramos; Moura, Sandra Aparecida Lima de; Cardoso, Leonardo Máximo; Ceron, Carla SperoniGreen propolis is a resin produced from Baccharis dracunculifolia, which has as its main compounds flavonoids, derivatives of cinnamic acids, such as artepillin C and baccarin. This resin has antibacterial, antifungal, anti-inflammatory, antioxidant, and anticancer activities. This review aimed to analyze pharmaceutical patents containing green propolis in various formulations. The search was conducted in the National Institute of Industrial Property (INPI), the Patent Search of Spain and Latin America (Latipat-Espacenet), the World Intellectual Property Organization (WIPO), and Google Patents, with a combination of the keywords green propolis, green propolis extract, pharmacology, and pharmaceutical product. Primary research identified 60 patents, from which 22 were selected after applying the inclusion criteria. The selected patents referred to products with pharmacological activities, from cancer treatment to food supplements and included innovations for improved controlled release of the green propolis compounds. Most of the documents concerned the preparation and/or formulation of the green propolis extract, followed by innovative extraction methods, treatment and systemic use, and finally by topical use and quality control techniques and procedures. Thus, the reviewed patents of green propolis provided valuable insights into the pharmaceutical applications of green propolis, showing its potential in diverse formulations and treatments.Item Geotechnical performance of isotropic and foliated quartzite waste as aggregate for road base and asphalt mixture.(2024) Mendonça, Whilison Marques; Marques, Geraldo Luciano de Oliveira; Gomes, Guilherme José CunhaQuartzite mines produce a large amount of waste. Although the reuse of materials is essential for sustainable constructions, little is known about the geotechnical properties of isotropic (massive) and foliated (discontinuous) quartzite waste. In this paper, the potential use of these wastes as base layers and asphalt mixtures were examined by a series of laboratory tests and numerical simulations. This paper presents an analysis of the particle properties, durability, strength, and deformation response of quartzite waste in isotropic (IGM) and foliated granular (FGM) mixtures. Asphalt mixtures with isotropic (IAM) and foliated (FAM) quartzite waste as aggregates are evaluated using Brazilian tensile strength, moisture susceptibility, and repeated-load indirect tension tests, such as the resilient modulus and fatigue. To estimate the performance of these materials as pavement layers, numerical experiments are also carried out using the mechanistic-empirical design framework of the MeDiNa software package. As a base material, the mixtures showed plastic creep responses at the highest stress level (higher permanent strain of 1.2 % at σ3/σd = 360/120 kPa) and negligible expansion. The California bearing ratio (higher than 130 % for both IGM and FGM) and resilient modulus (average of 224 and 130 MPa for IGM and FGM, respectively) greatly exceeded the minimum requirement of Brazilian standards. As asphalt mixtures, both IAM and FAM met the minimum limit of tensile strength, but IAM showed greater stiffness. According to the stress–strain analysis of the MeDiNa software, granular and asphalt mixtures incorporating quartzite waste fulfilled the fatigue crack area and rut depth criteria, falling within the allowed thickness ranges for road pavements subjected to up to 5 × 106 repetitions (medium heavy traffic). This study provides support for the transformation of quartzite waste into a valuable byproduct.Item Exploring tailings dam stability considering uncertainties in the critical state parameters of the NorSand Model.(2024) Silva, Alexandre Vilaça; Gomes, Guilherme José Cunha; Huertas, Jackeline Rosemery Castañeda; Cândido, Eduardo SouzaStability analyses of tailings dams often utilize advanced constitutive models that require the calibration of many parameters. Yet, there remains limited research on the implications of parameter uncertainties within these constitutive models on the safety factor of tailings dams. This study successfully investigated the impact of uncertainty in critical state parameters of the NorSand model on the stability of a tailings dam. To achieve this goal, feld and laboratory tests characterized the materials constituting the geotechnical profle of the dam, involving residual shale soils, alluvial soils, and granular-textured tailings. These tests were included in the fnite element (FE) program PLAXIS 2D to estimate several parameters of the constitutive models that characterized the materials of the dam: Hardening Soil, Mohr–Coulomb, and NorSand. Monte Carlo simulations of FE analyses were conducted considering the construction period of the dam spanning 2500 days. Furthermore, the critical state line (CSL) parameters employed within the NorSand model were reconciled with void ratio data for the uncompacted tailings utilizing a Bayesian framework. The Bayesian framework allowed us to investigate: (i) the statistical distribution of the critical state parameters, (ii) confdence intervals for horizontal and vertical displacements, (iii) shear strains at various monitoring points across the tailings dam, (iv) and the marginal distribution of the factor of safety. The fndings reveal a strong correlation between the three CSL parameters, which presented poorly defned statistical distributions. Nonetheless, the power law equation used to model the CSL closely matches laboratory data from triaxial tests (R2=0.97). Uncertainties in the CSL, especially at lower stress levels, contribute to settlement prediction uncertainties. Monitoring points at the structure’s base showed strains that could induce downstream slope instability and potential liquefaction failure. The histogram of the safety factors remained narrow, normally distributed, ranging from 1.39 to 1.47. This work is important because it explicitly addresses the uncertainty in the critical state parameters of the Nor-Sand model within geotechnical analysis.Item Assessing and managing safety risks to downstream communities (in hindsight) : what went wrong in the licensing and impact assessment procedures of Brazil’s deadliest dam breaks?(2024) Paiva, Camilla Adriane de; Barella, Cesar Falcão; Fonseca, Alberto de Freitas CastroEnvironmental impact assessment (EIA) is a policy tool used all around the world to predict, mitigate, and manage the impacts and risks of development proposals. This tool, if well implemented and articulated with licensing procedures, can result in improvements of project design and in the prevention and mitigation of environmental and social harms. But sometimes EIA can fail, as illustrated the collapse of the Brazilian tailings dams Fundão and B1, in 2015 and 2019 respectively. Despite having gone through licensing and EIA procedures, the two dams collapsed, killing almost 300 people. This study set out to understand how the vulnerability of downstream communities to dam breaks were predicted and managed in the dams’ EIA processes. This study also tried to understand whether the EIA process of a newly approved tailings dam in Brazil (Maravilhas Dam III) improved the prediction of safety risks to downstream communities. The study was based on literature reviews and a content analysis of eighty-four (84) key documents related to the dams’ licensing and EIA procedures. The study found that the risk-related studies of the dams were based on a variety of methods (e.g., Preliminary Hazard Analysis, Failure Mode and Effects Analysis, Dam Break simulations, Contingency Plans) that were implemented in different phases of the licensing procedures. It was possible to identify several flaws and limitations in these methods, such as vagueness, late implementation, fragmented reviews of interdependent risks, and low influence on decision-making. Both the Fundão and B1 dams were approved despite the lack of in-depth and up-to-date risk assessments. Public consultations were generally weak and plagued by tokenism. Post-approval procedures, while informed by monitoring, audits and inspections that confirmed problems in the dams, were unable to educate developers and State authorities about the likelihood of failures and the safety risks to communities. Overall, the Fundão and B1 cases show the importance of not only predicting but also managing risks in a timely, transparent and articulated manner. The Maravilhas III Dam, compared to Fundão and B1, was found to have sounder evaluations of safety risks and stronger public participation. The regulatory and voluntary frameworks concerning tailings dams have improved in recent years. The projects of Fundão and B1 could not receive an environmental license had they been subject to the current Brazilian legislation, because they proposed a now-banned technology (upstream dams) and had vulnerable communities located in self-rescue zones, which is now legally unacceptable. Despite these regulatory changes, there is still room to improve regulations, guidelines and Terms of References for risk analysis and its articulation with impact assessment and public participation. The article discusses the academic implications of the cases to international audiences and put forward several practical recommendations.Item Analyses of colloidal, truly dissolved, and DGT-labile metal species and phosphorus in mining area surrounded by tailing dams using self-organising maps.(2022) Gontijo, Erik Sartori Jeunon; Monteiro, Adnívia Santos Costa; Tonello, Paulo Sérgio; Roeser, Hubert Mathias Peter; Friese, Kurt; Rosa, André HenriqueThe knowledge of size-distribution and lability of metals and nutrients in freshwater systems is important for estimation of the ecological effects of mining. However, it is still limited in several mining areas such as the Quadrilatero ́ Ferrífero (Brazil) which was severely polluted by the collapse of the Fundão tailings dam in November 2015. In this study, results of an investigation from 2014 using a neural network named self-organising map (SO-Map) into the conditions of selected trace metals that are of particular importance to mining areas (Cr, Cu, Co, Mn, Ni, Pb, Zn) are presented. Additionally, P was considered by its high importance as a nutrient and sites later affected by the dam burst were also included by chance. Water samples were collected at six sites in dry and rainy seasons and filtered and ultrafiltered for determination of total dissolved (<0.45 μm) and truly dissolved (<1 kDa) fractions. Diffusive gradients in thin films (DGT) devices were deployed in situ for determination of the DGT-labile fraction. All data were analysed using SO-Map and Spearman’s rank correlation. Phosphorus in the Carmo River occurred mainly in the truly dissolved and DGT-labile fractions. The higher amounts of this element in the river water (up to 263 μg L− 1 of total P) might be related to untreated sewage discharge. Moreover, the concentrations of other trace metals (Mn, Cu, Co, Ni, Zn) were high, even under the “natural” conditions (before the dam failure) due to natural and anthropogenic factors such as local lithology and mining.Item Weak participation and ideological exemption : the latest stage of EIA simplification in Brazil?(2023) Fonseca, Alberto de Freitas CastroDevelopers’ concerns over the costs and delays of environmental impact assessment (EIA) have increasingly been driving ‘simplification’ solutions and reforms. This letter critically reviews the evolution of EIA simplification in Brazil. More specifically, it (1) sets out to describe the main stages of EIA simplification in Brazil, and (2) calls for conceptually clear and evidence-based simplification reforms. I argue that the first simplification efforts in Brazil mirrored an attempt to bring procedural proportionality to EIA. But simplification gradually became a more nuanced phenomenon reflecting a variety of streamlining, digitalization, and decentralization strategies. However, the many simplification efforts do not seem to be affecting developers’ predominant perception about EIA ineffectiveness. Brazil may be witnessing a more radical stage of EIA simplification, in which ‘simplicity’ is pursued through weak public participation and the exemption of specific economic sectors of the Brazilian economy from EIA. Without conceptually clear and evidence-based simplification reforms, debates over EIA effectiveness are likely to be influenced by simplistic win-win narratives, and Brazil’s increasingly fragile environment is likely to get worse.Item Weathering resistance of Linz–Donawitz (LD) slag as ballast material using freeze-thaw and sulfate soundness.(2023) Alves, Hebert da Consolação; Gomes, Guilherme José CunhaAs nonrenewable natural aggregates with acceptable geotechnical properties become scarce, costly, and entail negative environmental impacts, the study of alternatives remains a first-order challenge for sustainable railway design. This paper focuses on the physical and chemical weathering effects of the industrial byproduct Linz–Donawitz (LD) slag as a ballast material. For this purpose, 75 freeze–thaw (F-T) and 40 sulfate soundness (SS) cycles were carried out on the byproduct. We present a series of laboratory experiments involving particle characteristics, durability and strength for different F-T and SS cycles. To benchmark the performance of LD slag, we also performed our experiments on two natural aggregates: gneiss and basalt. Our main findings reveal that: (i) the shape of LD slag ballast and its particle size distribution are unnafected by the F-T and SS cycles, (ii) the basalt exhibits higher magnitudes of fouling after SS cycles, (iii) losses in Los Angeles abrasion and shock resistance were much more pronounced in SS tests for all ballast materials, (iv) LD slag is more resistant and less susceptible to the degrading effects of freezing and thawing, (v) point load tests indicate that the loss of resistance of basalt is small compared to that of gneiss, (vi) the byproduct showed a decrease in strength of 87% after 40 SS cycles, suggesting that chemical weathering exerts a dominant control on the performance of LD slag. The findings are relevant to elucidate the physical and chemical weathering effects of LD slag and to promote its sustainable use.Item Sodium butyrate-loaded nanoparticles coated with chitosan for the treatment of neovascularization in age-related macular degeneration : ocular biocompatibility and antiangiogenic activity.(2022) Reis, Júlia Stephania dos; Teixeira, Aniely dos Reis; Quaresma, Amanda de Vasconcelos; Almeida, Tamires Cunha; Arribada, Raquel Gregorio; Neto, Julia Teixeira; Silva, Fábio Henrique Rodrigues da; Cunha Júnior, Armando da Silva; Moura, Sandra Aparecida Lima de; Silva, Glenda Nicioli da; Fialho, Sílvia Ligório; Silva, Gisele Rodrigues daSodium butyrate-loaded nanoparticles coated chitosan (NaBu-loaded nanoparticles/CS) were developed to treat the choroidal neovascularization in wet age-related macular degeneration (AMD). The nanoparticles were produced by double emulsification and solvent evaporation technique, optimized by experimental statistical design, characterized by analytical methods, investigated in terms of in vitro and in vivo ocular biocompatibility, and evaluated as an antiangiogenic system in vivo. The NaBu-loaded nanoparticles/CS were 311.1 ± 3.1 nm in diameter with a 0.208 ± 0.007 polydispersity index; had a +56.3 ± 2.6 mV zeta potential; showed a 92.3 % NaBu encapsulation efficiency; and sustained the drug release over 35 days. The NaBu-loaded nanoparticles/CS showed no toxicity to human retinal pigment epithelium cells (ARPE-19 cells); was not irritant to the chorioallantoic membrane (CAM); did not interfere in the integrity of the retinal layers of rat’s eyes, as detected by the Optical Coherence Tomography and histopathology; and inhibited the angiogenesis in CAM assay. The NaBu-loaded nanoparticles/CS could be a therapeutic alternative to limit the neovascularization in AMD.Item Blending Linz–Donawitz and Blast Furnace slags with the Kambara reactor byproduct to improve their reuse in roadworks.(2022) Schumacher, Aécio Guilherme; Gomes, Guilherme José Cunha; Schneider, Denise S. G.; Pires, Patrício José Moreira; Gomes, Ruan Gonçalves de SouzaThe use of industrial byproducts as replacement of natural aggregates has been extensively investigated to design eco-friendly roads. One of the most examined byproducts for this purpose is steel slag. However, existing studies do not explore the blending of different slags to enhance the engineering performance of base layers. The applicability of Linz–Donawitz (LD), Blast Furnace (BF) and Kambara Reactor (KR) steel byproducts is evaluated as a single base layer for rural (unsurfaced) roads in Brazil. A series of laboratory experiments were performed to assess the characteristics of eight soil-byproduct mixtures with 50% and 75% byproduct contents, including new blends of LD/KR and BF/KR slags. Additionally, the most suitable mixture was proposed considering different performance indicators. Results demonstrate the coarse-grained, nonplastic and non-expansive nature of the byproducts, with CBR values higher than 100%. The more byproduct added to soil, the larger is the strength and the lower the expansion. The mixture with 75% of the proposed LD/KR blend and 25% of a clayey soil was considered as optimum, based on a trade-off between engineering properties, environmental impacts, and material costs. Findings and discussions are relevant to reduce waste stockpiles of steel companies, helping engineers and policy makers reuse blended slag byproducts.Item A hybrid multi-step sensitivity-driven evolutionary polynomial regression enables robust model structure selection.(2022) Gomes, Ruan Gonçalves de Souza; Gomes, Guilherme José Cunha; Vrugt, Jasper A.Evolutionary Polynomial Regression (EPR) has found widespread application and use for model structure development in engineering and science. This hybrid evolutionary approach merges real world data and explanatory variables to generate well-structured models in the form of polynomial equations. The simple and transparent models produced by this technique enable us to explore, via sensitivity analysis, the robustness of the derived models. Yet, existing EPR frameworks do not make explicit use of sensitivity analysis in the selection of robust and high-fidelity model structures. In this paper, we develop a multi-step sensitivity-driven method which combines the strengths of differential evolution and model selection via Monte Carlo simulation to explore the input–output relationships of model structures. In the first step, our hybrid approach automatically determines the optimum number of terms of the polynomial equations. In a subsequent step, our algorithm explores the mean parametric response of each explanatory variable used in the mathematical formulation to select a final model structure. Finally, in our selection of the most robust mathematical structure, we take explicit consideration of the prediction uncertainty of the simulated output. We illustrate and evaluate our EPR method for different engineering problems involving modeling and prediction of the moisture content and creep index of soils. Altogether, our results demonstrate that the use of sensitivity analysis as an integral part of model structure search and selection will lead to robust models with high predictive ability.Item Ferronickel slag as free‐draining rockfll dike material : a novel waste solution for mining regions.(2022) Costa, João Paulo Rodrigues da; Gomes, Guilherme José Cunha; Fernandes, Gilberto; Magarinos, Dario Mozzer; Fonseca, Alberto de Freitas Castro; Pires, Patrício José MoreiraMining sites are vulnerable to erosion and siltation of rivers. While the construction of rockfill dikes can mitigate siltation, existing rockfill dikes are typically constructed with natural aggregates, whose mining, beneficiation, and transportation entail additional adverse impacts. In this paper, ferronickel slag (FNS) was investigated as a free-draining rockfill dike material to be used in nearby mining sites. A series of laboratory tests, including physical, environmental, durability, chemical and mineralogical analyzes, was executed to evaluate the engineering characteristics of this byproduct and its potential use in dikes. Results demonstrate that FNS is non-uniform with relatively low Los Angeles abrasion. Leaching and dissolution tests have not shown harm to the environment since the average concentrations of chemical elements existing in FNS were below the standard requirements. Accelerated weathering cycling tests with ethylene glycol further highlighted that the byproduct does not suffer premature disaggregation in the presence of water, thereby revealing that the material can be employed adequately under saturated condition. Findings suggest that the use of FNS in rockfill dikes represents a technically and environmentally feasible solution, while reducing the use of natural aggregates, avoiding the formation of stockpiles, preventing siltation in downstream fluvial networks and other adverse impacts.Item Understanding the environmental impact of a mine dam rupture in Brazil : prospects for remediation.(2019) Santos, O. S. H.; Avellar, F. C.; Alves, M.; Trindade, R. C.; Menezes, M. B.; Ferreira, M. C.; França, G. S.; Cordeiro, Juni Silveira; Sobreira, Frederico Garcia; Yoshida, Maria Irene; Moura, P. M.; Scotti, M. R.The rupture of the Fundão mine dam in Mariana municipality, Minas Gerais State, Brazil, spilled the tailings across the Doce River basin. These tailings, composed of residues discarded from the beneficiation of iron ore, are rich in SiO2 and Al2O3, as well as some ether amine compounds and NaOH. The aim of this study was to assess the distribution of these sediments, as well as their effect on the riparian zones reached, as compared with preserved sites. Sediment deposition in the river resulted in a morphological change from a meandering profile to a braided aspect. The nutrient and mineral content (P, K, Ca, Mg, Cu, Fe, Mn, Zn, and NO3−) and soil organic matter of the sediments were depleted, whereas NH4+, Na, and pH increased. A random presence of ether amines in the sediments was confirmed by quantitative and chromatographic analyses, with concentrations ranging from 0 to 57.8 mg kg−1; Na reached values as high as 150 mg kg−1. The impact of the dam tailings on biota was assessed by estimating total microbial biomass (phospholipid fatty acids), which were depleted in sediments relative to soils from preserved sites. Overall plant mortality, as well as a low resilience capacity, were also observed. Ether amines and Na present in the sediments had a strong toxic effect in the environment. Identification of these substances as the main impact factors will help guide future remediation efforts.Item Effects of Psidium guajava L. leaves extract on blood pressure control and IL-10 production in salt-dependent hypertensive rats.(2022) Braga, Daiane Cristina de Assis; Gomes, Paula Magalhães; Batista, Marcos Adriano Carlos; Souza, Jaqueline Aparecida de; Bastos, Juliana Cristina Santos Almeida; Dôres, Rosana Gonçalves Rodrigues das; Alzamora, Andréia Carvalho; Souza, Gustavo Henrique Bianco de; Moura, Sandra Aparecida Lima de; Silva, André Talvani Pedrosa da; Antunes, Vagner Roberto; Cardoso, Leonardo MáximoPsidium guajava (guava) leaves extract displays anti-hypertensive properties by mechanisms not yet fully un- derstood. Here, we investigated whether sympathetic drive and immune signaling mechanisms are involved with the antihypertensive effect of the guava extract in a model of salt-dependent hypertension. Raw guava extract (rPsE) was characterized by colorimetric and UPLC-MS techniques. Two doses of rPsE (100 and 200 mg/kg) were evaluated for anti-hypertensive effect using a suspension system (PsE). Weaned male Wistar rats were put on a high-salt diet (HSD, 0.90 % Na+) for 16 weeks and received gavages of PsE for the last 4 weeks. Blood pressure (BP) was measured at the end of treatment in conscious rats. The neurogenic pressor effect was assessed by ganglionic blockade with hexamethonium. Autonomic modulation of heart rate was evaluated by spectral analysis. The effects of orally administered PsE on lumbar sympathetic nerve activity (LSNA) were assessed in anesthetized rats. Blood IL-10, IL-17A, and TNF were measured. The increased neurogenic pressor effect of HSD rats was reduced by PsE 100 mg/kg, but not by 200 mg/kg. PsE (200 mg/kg) administration in anesthetized rats produced a greater fall in BP of HSD rats compared to standard salt diet (SSD) rats. PsE hypotensive response elicited an unproportionable increase in LSNA of HSD rats compared to SSD rats. PsE (200 mg/kg) increased plasma concentrations of IL-10 but had no effect on TNF or IL-17A. Our data indicate that the antihypertensive effects of PsE may involve autonomic mechanisms and immunomodulation by overexpression of IL-10 in salt- dependent hypertensive rats.