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Classificação das barragens de rejeito baseada no risco de eventos indesejaveis utilizando dados do SIGBM – Sistema Integrado de Gestão de Barragens de Mineração da ANM.
No full textPrograma de Pós-Graduação em Engenharia Geotécnica. Núcleo de Geotecnia, Escola de Minas, Universidade Federal de Ouro Preto.A segurança de barragens de rejeito é um tema crucial no setor de mineração, especialmente após os trágicos desastres ocorridos nos últimos anos. Neste contexto, a gestão de riscos em barragens é um assunto cada vez mais relevante, sendo crucial entender e mitigar os riscos envolvidos na construção, operação e manutenção dessas estruturas complexas e críticas, que apresentam riscos potenciais para as pessoas e o meio ambiente. Portanto, a análise de risco em barragens de rejeitos é uma etapa essencial para identificar, quantificar e mitigar os riscos associados a essas estruturas. No contexto das barragens de rejeito, a classificação de risco é aplicada para avaliar os riscos relacionados à estabilidade e segurança dessas estruturas. É um processo que envolve a análise de diversos fatores, tais como a geometria da barragem, método construtivo, características do rejeito armazenado, condições operacionais, sistema de drenagem, entre outros. Desta forma, a classificação de risco busca identificar e categorizar as barragens em diferentes níveis de risco, utilizando uma escala que varia de baixo a muito alto. A gestão de segurança em barragens de rejeitos enfrenta desafios significativos. Os processos envolvidos são complexos, as condições geotécnicas e hidrológicas são variáveis, e os dados disponíveis são limitados. Desta maneira, a metodologia proposta neste trabalho tem como principal objetivo realizar uma classificação de risco das barragens de rejeito utilizando os dados do SIGBM- Sistema Integrado de Gestão de Barragens de Mineração da ANM. Espera- se, então, proporcionar uma classificação geral das estruturas por meio do risco obtido para cada uma das barragens estudadas, assim como mensurar de forma quantitativa a vulnerabilidade, o potencial de risco e a consequência de um possível evento indesejado para cada estrutura, por fim fazer uma comparação com atual classificação do próprio SIGBM. Neste estudo foram avaliadas 203 barragens inseridas na Política Nacional de Segurança Barragens localizadas no Estado de Minas Gerais.Tailings dam safety is a crucial issue in the mining sector, especially after the tragic disasters that have occurred in recent years. In this context, risk management in dams is an increasingly relevant subject, and it is crucial to understand and mitigate the risks involved in the construction, operation and maintenance of these complex and critical structures, which present potential risks to people and the environment. Therefore, risk analysis of tailings dams is a crucial step to identify, quantify and mitigate the risks associated with these structures. In the context of tailings dams, risk classification is applied to assess the risks related to the stability and safety of these structures. It is a process that involves an analysis of several factors, such as the geometry of the dam, construction method, characteristics of the stored waste, operational conditions, drainage system, among others. In this way, the risk classification seeks to identify and categorize dams at different risk levels, using a scale that varies from low to very high. Safety management in tailings dams faces important challenges. The processes involved are complex, the geotechnical and hydrological conditions are variable, and the available data is limited. The risk classification of tailings dams is an essential component in the safety management of these structures. However, the lack of standardized and comprehensive methodologies for classifying risk in tailings dams has resulted in an inconsistent and insufficient approach to identifying, assessing and prioritizing associated risks. Therefore, the methodology proposed in this work has the main objective of carry out a risk classification of tailings dams using data from SIGBM - ANM's Integrated Mining Dam Management System. The aim is to provide a general classification of the structures by means of the risked obtained for each of the dams studied, as well as to quantitatively measure the vulnerability, risk potential and consequence of a possible unwanted event for each structure. This study evaluated 203 dams included in the National Dam Safety Policy located in the state of Minas Gerais
Lithological controls of phosphatization in oceanic islands, Equatorial Atlantic, Brazil.
No full textThe São Pedro and São Paulo archipelago (SPSPA) is noteworthy for its unusual lithology when compared to other oceanic archipelagos, consisting of mylonitized and serpentinized peridotites, and rare carbonate sedimentary rocks. There, marine bird species use these substrates as a nesting ground and excrement deposition (i.e. guano), resulting in widespread phosphatization of local substrates. The unique geological nature of the SPSPA makes it particularly fascinating for geochemical and mineralogical research since diverse lithological, microstructural and microchemical attributes are present. This study aims to investigate the microscale chemical and mineral composition of the phosphatization materials in SPSPA, in relation to different geological substrates and associated mineralogy. Speleothems of secondary phosphates formed in fractures and on the walls, as a result of guano percolation. The microstructural control is the primary factor, which depends on the degree of rock fracturing. Wider and interconnected fractures allow the gravitational flow of cations and phosphate rich solutions with resulting phosphatization. Secondary factor is the substrate/guano interaction, which contributes to the precipitation of secondary phosphate minerals. The microchemical control is influenced by the degree of serpentinization, which leads to the generation of iron phosphates with structural potassium and aluminum. Phosphatization of sedimentary rocks is associated with pre-existing fractures and cavities, as well as the carbonate composition of the rock. This study enhances our understanding of varying ornithogenesis in the SPSPA, with a specific emphasis on the process of phosphatization of oceanic islands. Understanding this process can assist in understand the genesis of phosphate deposits in comparable environments, enhancing the knowledge of the biogeochemical cycle of phosphorus on Earth
Activity of extracts and terpenoids from Tontelea micrantha (Mart. ex Schult.) A.C.Sm. (Celastraceae) against pathogenic bacteria.
No full textThe pharmacological properties of plant extracts and phytochemicals, such as flavonoids and terpenoids, remain of great interest. In this work, the effect of extracts, friedelan-3,21-dione, and 3β-O-D-glucosyl-sitosterol isolated from Tontelea micrantha roots was evaluated against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Klebsiella oxytoca and Escherichia coli. The antibacterial activity was evaluated by the minimum inhibitory and bactericidal concentrations (MIC and MBC, respectively), and the synergistic effect was assessed by the Checkerboard assay. Furthermore, the cytotoxicity of the plant-derived compounds against Vero cells was measured by the 3-(4 5-dimethylthiazol-2-yl)-2 5-diphenyltetrazolium bromide (MTT) method. The biological effects of the isolated compounds were predicted using the PASS online software. The chloroform and hexane extracts of T. micrantha roots showed promising antibacterial effect, with MIC in the range of 4.8–78.0 μg/mL. Further analyses showed that these compounds do not affect the integrity of the membrane. The combination with streptomycin strongly reduced the MIC of this antibiotic and extracts. The extracts were highly toxic to Vero cells, and no cytotoxicity was detected for the two terpenoids isolated from them (i.e. friedelan-3,21-dione and 3β-O-D-glucosyl-sitosterol; CC50 > 1000 μg/mL). Therefore, extracts obtained from T. micrantha roots significantly inhibited bacterial growth and are considered promising agents against pathogenic bacteria. The cytotoxicity results were very relevant and can be tested in bioassays
Potencial de uma vacina quimérica associada ao adjuvante Poly ICLC frente à Leishmaniose visceral experimental.
No full textPrograma de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa de Pós Graduação, Universidade Federal de Ouro Preto.Dada sua expansão em centros urbanos, a leishmaniose visceral canina (LVC) é um problema de saúde pública de difícil controle diante da alta prevalência de cães infectados assintomáticos. Destaca-se a necessidade de desenvolver uma vacina eficaz para uso profilático em campanhas de vacinação. Além de segura e eficaz em ativar a resposta imune, a imunização deve ser administrada por uma via de fácil acesso e, de preferência, indolor. Dentre as vias parenterais, a via subcutânea é comumente utilizada devido ao fácil acesso e segurança, além de afetar a magnitude, a duração e a geração de memória imunológica específica frente ao antígeno vacinal dada a diversidade de células apresentadoras de antígenos (APCs) na pele. A imunização intradérmica também surge como uma opção atrativa, principalmente a partir do uso de dispositivos, como é o caso das microagulhas. O presente estudo avaliou o desempenho vacinal de uma proteína quimérica associada ao adjuvante Poly ICLC quanto à sua capacidade em gerar uma resposta imune efetiva e protetora frente ao desafio por Leishmania infantum em camundongos BALB/c. Os camundongos foram divididos segundo os grupos experimentais: controles (i) Salina e (ii) Adjuvante (Hiltonol®), e a (iii) Quimera A isolada (Qui-A) ou (iv) associada ao adjuvante vacinal (Qui-A/Hiltonol®). Os camundongos foram submetidos a três imunizações via intradérmica, empregando microagulhas ocas, ou via subcutânea, com intervalo de quinze dias entre elas. Após quinze dias da terceira imunização, parte dos camundongos foi eutanasiado e o restante desafiado com 1×106 formas promastigotas de L. infantum (MCAN/BR/2008/OP46). Após quarenta e cinco dias do desafio experimental, os camundongos foram eutanasiados. Os experimentos foram conduzidos em duplicata (n=6+6/grupo). Avaliamos o perfil de imunoglobulinas séricas IgG total e as subclasses IgG1 e IgG2a anti-Qui-A, e a produção de citocinas intracitoplasmáticas, a proliferação de células T e suas subpopulações, e a geração e diferenciação em células T de memória efetora (TME), central (TMC) e residente (TMR). Adicionalmente, quantificamos a carga parasitária hepática e esplênica. Observamos aumento na produção de IgG total e da subclasse IgG1 após imunização tanto com Qui-A quanto Qui-A/Hiltonol®, a qual também desencadeou a produção da subclasse IgG2a, sugestivos de uma resposta equilibrada TH1/TH2. Observamos aumento do percentual de células T CD4+CD44+ e T CD8+CD44+ produtoras das citocinas IL-2, TNF e IFN- após o término do protocolo de imunização e após o desafio experimental, e redução do percentual de células T CD4+ e T CD8+ produtoras da citocina IL-10. Independentemente da via de imunização empregada, houve o estabelecimento de um perfil de resposta TH1, sustentado pela razão IFN- + /IL-10+ aumentada. Tanto a imunização com Qui-A quanto com Qui-A/Hiltonol® elevaram o percentual de proliferação de células T totais, T CD4+ e T CD8+ . A imunização com Qui-A/Hiltonol® estimulou a diferenciação de células TME e TMC específicas após o término do protocolo de imunização e após o desafio experimental no baço, exceto para as células TME CD8+ após o desafio experimental. Cabe destacar que apenas a imunização subcutânea estimulou a diferenciação das células TME CD8+ após o protocolo de imunização. As células TMR aumentaram significativamente no fígado após o protocolo de imunização com Qui- A/Hiltonol®, independentemente da via de imunização. Por fim, observamos carga parasitária hepática e esplênica reduzida após o protocolo de imunização com Qui-A/Hiltonol®, as quais se relacionaram com o aumento das células T que expressam os fenótipos de memória. A imunização apresentou potencial para promover imunidade protetora contra a infecção por L. infantum. A despeito disso, há restrições para a generalização dos dados obtidos em modelos murinos para outros hospedeiros, o que demanda a realização de futuras investigações para análise da segurança, imunogenicidade e potência em hamsters, cães e/ou humanos.Given its expansion in Brazilian urban centers, canine visceral leishmaniasis (CVL) is considered a public health problem that is difficult to control due to the high prevalence of asymptomatic infected dogs. Therefore, the need to develop an effective and safe vaccine for prophylactic use in vaccination campaigns stands out. In addition to being safe and effective in activating the immune response, immunization must be administered through an easily accessible and, preferably, painless route. Among the parenteral routes, the subcutaneous route is commonly used due to easy access and safety, in addition to affecting the magnitude, duration, and generation of specific immunological memory against the vaccine antigen since skin presents several antigen-presenting cells (APCs). Intradermal immunization also emerges as an attractive option, mainly using recently developed devices, such as microneedles. Therefore, the present study evaluated whether the vaccine performance of a chimeric protein adjuvanted with the Poly ICLC can generate an effective immune response, memory T-cells, and protection against L. infantum challenge in BALB/c mice. Then, the mice were divided according to experimental groups: (i) Saline and (ii) Adjuvant (Hiltonol®) control groups, and (iii) Chimera A alone (Chi-A) or (iv) adjuvanted with Poly ICLC (Chi-A/Hiltonol®). The mice underwent an immunization protocol, which consisted of three doses intradermally in the left thigh using hollow microneedles or subcutaneously in the dorsum using a hypodermic needle, with an interval of fifteen days between doses. Subsequently, fifteen days after the third immunization, part of the mice were euthanized. The remaining animals were intravenously challenged with 1×106 stationary-phase L. infantum promastigotes (MCAN/BR/2008/OP46). After forty-five days, the mice were euthanized. Experiments were carried out in duplicate (n=6+6/group). We evaluated the serum immunoglobulin profile of total IgG and the IgG1 and IgG2a anti-Chi-A, and the intracellular cytokines production (IL-2, TNF, IFN- and IL-10), the proliferation of T cells and CD4+ and CD8+ T cell subsets, and the generation and differentiation into effector (TME), central (TMC) and resident (TMR) memory T-cells. Additionally, we quantified the hepatic and splenic parasite load. We observed an increase in total IgG and the IgG1 subclass production with both Chi-A and ChiA/Hiltonol® immunization, which also triggered IgG2a subclass production, suggesting a balanced TH1/TH2 response. We observed an increase in the percentage of IL-2, TNF, and IFN--producing CD4+CD44 + and CD8+CD44 + T cells post-immunization and post-challenge and reduced the percentage of IL-10-producing CD4+ and CD8+ T cells post-challenge. We found an establishment of TH1-type immune response supported by the increased IFN- + /IL-10+ ratio, regardless of the immunization route. Both Chi-A and Chi-A/Hiltonol® immunization enhanced the proliferation percentage of total T cells and CD4+ and CD8+ T cells. Chi-A/Hiltonol® immunization also induced effector and central memory T-cell subsets differentiation post-immunization and post-challenge in the spleen, except for CD8+ effector T-cell memory post-challenge. It is noteworthy to mention that only subcutaneous immunization stimulates CD8+ TEM cells post-immunization. Notably, tissue-resident memory T cells were significantly increased in the liver, regardless of the immunization route. Lastly, Chi-A/Hiltonol® immunized mice exhibited a remarkable reduction in the hepatic and splenic parasite load, which was correlated with the increased memory phenotypes-expressing T cells. Immunization showed the potential to promote protective immunity against L. infantum infection. Nevertheless, there are restrictions on the generalization of data obtained in murine models to other hosts, which requires future investigations to analyze safety, immunogenicity, and efficacy in hamsters, dogs, and/or humans
Complex tribology of bolted assembly.
No full textThreaded fasteners are widely used in various popular areas such as mechanical, civil, transport, medical, space, and many more because of extreme assembly and disassembly facilities. An everyday activity during the use of bolts is their reuse. In this work, inorganic and organic topcoats were used as a lubricant to investigate their influence on tribological properties. Grease-based lubrication was used after the three-time cyclic tightening to find the performance when it was reused. The tightening process was divided into two steps: from the specific torque value to the yield point. The clamping force and the surface morphology was monitored and analysed during cyclic tightening. Experimental results showed that the use of lubrication was able to increase the clamping force of the threaded fasteners. With an inorganic topcoat, obtained clamping force during cyclic tightening was more stable than that using organic topcoat. Even through significant friction and wear were observed during cyclic tightening, the higher clamping force can also be kept with additional lubricant when threaded fasteners were reused. The results helped to provide insight into the influence of surface treatment on the tribological behaviour of threaded fasteners during cyclic tightening
El cine de Larissa Sansour y la solución de un solo Estado al conflicto palestino-israelí.
No full textEste artigo busca compreender como a cineasta palestina Larissa Sansour mobiliza a luta anticolonialista palestina contra a ocupação sionista através da análise fílmica de Patrimônio Nacional (2013). Além de refletir a respeito das interações entre as imagens do filme dentro da própria narrativa, relacionamos a obra com as categorias violência, território, temporalidade e vestígios; entrevistas da cineasta sobre seu trabalho e a situação da Palestina; e com os recentes acontecimentos pós 7 de outubro de 2023. Além disso, investigamos como Sansour se apropria do gênero da ficção científica e seus tropos, como elementos constitutivos para criar um filme-manifesto baseado nas teorias decoloniais de autores como Achille Mbembe (2018), Ilan Pappé (2016) e Edward Said (2012), tensionando os conceitos e apontamentos deles junto à narrativa fílmica, principalmente os que se referem aos efeitos prolongados de processos de colonização como o estabelecido por Israel na Palestina desde 1948. Mais do que refletir sobre a colonização, entendemos que Larissa Sansour, através de Patrimonio Nacional, se estabelece como uma força anticolonial, endereçando uma contundente crítica ao sionismo e aos empreendimentos capitalistas que acompanham processos de colonialidade como este.Este artículo busca comprender cómo la cineasta palestina Larissa Sansour moviliza la lucha anticolonialista palestina contra una ocupación sionista a través del análisis cinematográfico de Patrimônio Nacional (2013). Además de reflexionar sobre las interacciones entre las imágenes de la película dentro de la propia narrativa, relacionamos la obra con las categorías de violencia, territorio, temporalidad y huellas; entrevistas con la cineasta sobre su trabajo y la situación en Palestina; y con los acontecimientos recientes posteriores al 7 de octubre de 2023. Además, investigamos cómo Sansour se apropia del género de ciencia ficción y sus tropos y elementos constitutivos para crear una película manifiesto basada en teorías decoloniales de autores como Achille Mbembe (2018), Ilan Pappé (2016) y Edward Said (2012), tensionando sus conceptos y apuntes junto con la narrativa fílmica, especialmente aquellos que hacen referencia a los efectos prolongados de procesos de colonización como el establecido por Israel en Palestina desde 1948. Más que reflexionar sobre la colonización, entendemos que Larissa Sansour, a través de Patrimonio nacional, se establece como una fuerza anticolonial, lanzando una crítica mordaz al sionismo y a las empresas capitalistas que acompañan procesos de colonialidad como este
r-primitive k-normal elements in arithmetic progressions over finite fields.
No full textLet Fqn be a finite field with qn elements. For a positive divisor r of qn − 1, the element α ∈ F∗ qn is called r-primitive if its multiplicative order is (qn − 1)/r. Also, for a non-negative integer k, the element α ∈ Fqn is k-normal over Fq if gcd(αxn−1 + αqxn−2 +···+ αqn−2 x + αqn−1, xn − 1) in Fqn [x] has degree k. In this paper we discuss the existence of elements in arithmetic progressions {α, α+β, α+2β, ...α+(m−1)β} ⊂ Fqn with α+(i−1)β being ri-primitive and at least one of the elements in the arithmetic progression being k-normal over Fq. We obtain asymptotic results for general k, r1, ... , rm and concrete results when k = ri = 2 for i ∈ {1, ... , m}
Origin and significance of macroscopic organic aggregates from the lacustrine Aptian Crato Konservat-Lagerstätte.
No full textThe Crato Konservat-Lagerstätte is one of the main Mesozoic fossil sites from Gondwana, recording a wide diversity of terrestrial and non-marine aquatic fossils of great paleobiological and evolutionary significance. This conservation deposit is recorded in a 9 m-thick interval of laminite, microbialite, and grainstone deposited in a lake system with variable water level, alternating moments of hypersaline and freshwater conditions. Despite numerous studies describing new species of plants, arthropods, fish, pterosaurs, birds, and many others, there remains a significant gap in our understanding of the most common and archetypal fossils, which are the rod-shaped macrofossils found on bedding surfaces in distinct stratigraphic intervals of the Crato Konservat-Lagerstätte. The rodshaped macrofossils are up to 1.6 cm-long and 0.1 cm-wide, straight to curved compressions that preserve pyritized microfossils. Here we interpret the rod-shaped macrofossils as macroscopic organic aggregates that sank into the lakebed in a process called lake snow. During high organic productivity periods in the epilimnion, planktonic organisms thrived and produced exopolymers responsible for aggregation. Their concentrations in the limestone bedding planes reflect intensity of lake snow and environmental seasonality. Aggregates are prolate particles that are commonly oriented, suggesting their transport as bedload for short distances, which was facilitated by biostabilization by microbes and their exopolymers. Finally, pyritization was mediated by microbial communities living in the lakebed
Óleos básicos vegetais biodegradáveis como potencial alternativa aos óleos básicos convencionais : comparação das propriedades físico-químicas e tribológicas e viabilidade econômica na formulação de biolubrificantes automotivos e industriais.
No full textA demanda de energia global apresenta uma projeção de crescimento entre os anos de 2010
e 2030 de 33,5%. Esta expectativa impacta diretamente no consumo do petróleo, fonte principal dos
óleos básicos utilizados na formulação de óleos lubrificantes. Atualmente, estima-se que estes óleos
minerais são usados em 95% do volume global de lubrificantes. A grande preocupação sobre este tipo
de produto é a sua disposição incorreta no meio ambiente, uma vez que de 40% a 55% do volume
total não possuem uma logística reversa apropriada. Diante desta necessidade por fontes renováveis
de energia, preocupações com políticas ambientais como o ESG, depreciação das reservas de óleos
brutos, criação de normas internacionais como a MARPOL 73/78 e crescimento da participação dos
biolubrificantes nos setores de transporte e equipamentos pesados, os óleos básicos biodegradáveis
têm se mostrado fortes candidatos a substituírem as bases convencionais nas formulações dos
lubrificantes, total ou parcialmente. Estes produtos são, em sua maioria, polialfaolefinas (PAOs)
polialquilenoglicois (PAGs), ésteres sintéticos e ésteres naturais provenientes de fontes animais e/ou
vegetais. Para o presente trabalho, os principais óleos vegetais foram mapeados aplicando equações
de busca (bibliometria) nas bases de dados Web of Science e Scopus a fim de definir suas fontes bem
como a frequência com que eles são discutidos nas produções científicas. O Brasil produziu em 2019
cerca 35.000 m3
de lubrificantes biodegradáveis, volume que corresponde a, aproximadamente 2,65%
da produção total nacional neste mesmo ano. As bases biodegradáveis utilizadas nestas formulações,
quando comparadas físico-quimicamente com os óleos básicos minerais, apresentam baixa
toxicidade, boa lubricidade, elevado ponto de fulgor, elevado índice de viscosidade, baixa volatilidade
e boa resistência ao cisalhamento. Por outro lado, a pouca eficiência na resistência à oxidação e a
fluidez limitada em baixas temperaturas geram necessidade de modificar quimicamente estas bases
para que elas sejam utilizadas na formulação dos biolubrificantes. Quando se avalia os custos das
bases sustentáveis, nota-se que elas se tornam competitivas à medida que as comparações são feitas
com óleos convencionais mais refinados, como os de Grupo III e PAOs, por exemplo. No entanto,
óleos minerais, principalmente no cenário nacional devido ao refino local, ainda se posicionam mais
competitivos. Frente a estes expostos, um caminho interessante a ser seguido é avaliar o uso conjunto
das bases convencionais e biodegradáveis a fim de se obter um custo atrativo e desempenho adequado
para o lubrificante final, além de contribuir com a descarbonização do setor e reduzir a sua pegada de
carbono.
Palavras-chave: biolubrificantes, óleos vegetais, sustentabilidade, pegada de carbono, ESG,
bibliometria.he global energy demand presents a growth projection of 33.5% between the years
2010 and 2030. This expectation directly impacts the consumption of oil, the primary source of
base oils used in lubricating oil formulations. Currently, it is estimated that these mineral oils
are used in 95% of the global lubricant volume. The major concern regarding this type of
product is its improper disposal into the environment, as from 40% to 55% of the total volume
lack proper reverse logistics. In the face of the need for renewable energy sources,
environmental policy concerns such as ESG, depreciation of crude oil reserves, the
establishment of international standards like MARPOL 73/78, and the increasing role of
biolubricants in transportation and heavy equipment sectors, biodegradable base oils have
emerged as strong candidates to replace conventional bases in lubricant formulations, either
entirely or partially. These products are primarily composed of polyalphaolefins (PAOs),
polyalkylene glycols (PAGs), synthetic esters, and natural esters derived from animal and/or
vegetable sources. For this study, the primary vegetable oils were mapped using search
equations (bibliometrics) in the Web of Science and Scopus databases to determine their
sources and frequency of discussion in scientific literature. In 2019, Brazil produced
approximately 35,000 m3
of biodegradable lubricants, which corresponds to approximately
2.65% of the total national production in the same year. The biodegradable bases used in these
formulations, when compared to the physicochemical parameters of mineral base oils, exhibit
low toxicity, good lubricity, high flash point, high viscosity index, low volatility, and good
shear stability. On the other hand, their limited oxidation resistance and restricted fluidity at
low temperatures necessitate chemical modifications to make these bases suitable for
biolubricant formulations. When evaluating the costs of sustainable bases, they become
competitive when comparisons are made with more refined conventional oils, such as Group
III and PAOs, for example. However, mineral oils, especially in the Brazilian context due to
local refining, still maintain a competitive position. Given these factors, an interesting approach
to consider is the joint use of conventional and biodegradable bases to achieve an attractive cost
and suitable performance for the final lubricant, in addition to contributing to the decarbonization
of the sector as well as reducing its carbon footprint
Characterization of the Brazilian musical landscape : a study of regional preferences based on the Spotify charts.
No full textIn the digital age, streaming services such as Spotify have changed
the way people consume music, highlighting the enormous influence these platforms have on the market. In the highly competitive
music industry, it is crucial for independent artists in particular to
maintain their popularity. This is especially true in countries like
Brazil, where geographical and cultural differences influence music
consumption patterns. Understanding these patterns is essential for
effective marketing and production strategies. Despite previous research on music consumption, genre preferences and user behavior,
there is a lack of detailed studies on the geographical and cultural
distribution of music preferences in Brazil. Our study fills this gap
by examining musical genre preferences and acoustic features of
tracks across Brazilian regions over two years. We collected Spotify chart data from 2022 and 2023, modeled bipartite genre-city
networks, and used backbone extraction methods to highlight significant genre preferences. Temporal analysis revealed patterns and
persistence of musical preferences across cities, while clustering
techniques revealed regional and cultural differences in acoustic
features. Our results show that genre preferences are stable across
Brazilian regions, with important genres emphasized by backbone
networks. Persistence analysis suggests minimal changes over time,
except during major holidays. Furthermore, Brazilian city clusters
exhibit distinct acoustic patterns regardless of music genres, with
notable differences in features such as liveliness, speechiness, and
valence. This research provides new insights into regional musical
diversity in Brazil and paves the way for future studies on cultural
and geographical influences on music preferences