124 research outputs found
Superhydrophobic Coatings for Corrosion Protection of Stainless Steel
Get PDFCorrosion is a persistent challenge in the aviation industry, affecting the safety, performance, and maintenance costs of aircraft. While composite materials have gained widespread use due to their lightweight properties and corrosion resistance, certain critical parts, such as the wing and empennage leading edges and the engine inlet, demand alternative solutions. Aluminum, titanium, and stainless steel emerge as mandatory materials for such components, given their exceptional strength and durability. However, protecting these metallic components from corrosion remains crucial. In this paper, we present a study aimed at evaluating the corrosion resistance of stainless steel, employed as an erosion shielding panel for a composite vehicle’s wing, layered with a superhydrophobic coating. The samples with and without coating have been characterized by contact angle measurements, microscopy (optical and electronic), and visual inspection after immersion in two solutions, NaCl and NaOH, respectively. The application of the superhydrophobic coating demonstrated a significant reduction in corrosion extent, especially in the demanding NaCl environment. This was evidenced by diminished formation of ripples and surface roughness, decreased iron oxide formation from oxidative processes, and a lower Surface Free Energy value in both liquid environments. Notably, the surface maintained its superhydrophobic properties even following an 8-day immersion in NaCl and NaOH solutions, demonstrating the reliability of the superhydrophobic coating offering as a potential solution to enhance the longevity and reliability of aircraft structures
MOBILE URBANITY. Translocal Traders and City in Southern Africa
No full textPiscitelli P. (2018), MOBILE URBANITY. Translocal Traders and City in Southern Africa, Planum Publisher, Roma-Milano | ISBN 9788899237141
See the preview of the publication on ISSUU.com (below) and download the full text (above and on the right column)!
As many translocal and cross-border traders, mukheristas cover thousands of miles every week to supply urban markets, thus feeding themselves, their families and the cities they connect.
After an intensive field work travelling with mukheristas between Maputo (Mozambique) and Johannesburg (South Africa), the author shows the role of complex hybrid practices of trans-local mobility in shaping cities and territories in sub-saharan Africa.
A "research on the road" to reflect on the political relevance of informal mobile practices in troubled urban societies, but also on new theoretical concepts and empirical research approaches.
In a world where change is extremely rapid and new issues emerge unremittingly, 'Mobile urbanity' opens up new ways of thinking the spatial dimensions and the agency embraced in human mobility
Enhancing Coating Adhesion on Fibre-Reinforced Composite by Femtosecond Laser Texturing
Get PDFCarbon fibre-reinforced polymers (CFRP), thanks to their properties such as lightness, resistance to corrosion and fatigue, are emerging composite materials in the aeronautic fields, guaranteeing to reduce weight and costs by maintaining high performances in terms of strength and security. For preventing fluid damage and freezing, in aeronautic applications, CFRP parts need to be coated by painting. However, the paint/coating adhesion on CFRP composites is generally poor and affected by surface conditions. In this work, femtosecond laser texturing was investigated as an approach to improve adhesion of superhydrophobic coatings (SHC) to CFRP substrates. The laser textured surfaces show, after coating, a more lasting superhydrophobic behaviour compared to the as received sample, even after several cleaning cycles, demonstrating that the laser pre-treatment is a reliable and green method to enhance the adhesion of the SHC to the composite substrate
Maria Filomena Gregori
Get PDFEntrevista de Maria Filomena Gregori a Silvia Aguião.Maria Filomena Gregori interview by Silvia Aguião.Maria Filomena Gregori é Professora livre-docente do Departamento de Antropologia na Universidade de Campinas e pesquisadora associada ao Pagu – Núcleo de Estudos de Gênero, sendo membro do seu Conselho Científico. Graduada em Ciências Sociais pela Universidade Estadual de Campinas, mestre em Ciência Política pela Universidade de São Paulo e doutora em Antropologia Social pela Universidade de São Paulo Foi presidente da Associação Brasileira de Antropologia em 2019 e 2020, coordenadora do Doutorado de Ciências Sociais do Instituto de Filosofia e Ciências Humanas. Membro do conselho consultor da Rede Universitária de Direitos Humanos e membro do conselho consultivo do Centro Latino-Americano de Sexualidade e Direitos Humanos e do Conselho Editorial da Contemporânea – Revista de Sociologia, da Universidade Federal de São Carlos. Tem experiência na área de Antropologia, atuando principalmente nos seguintes temas: gênero, estudos de gênero, violência urbana e antropologia urbana. Publicou os seguintes livros: Prazeres Perigosos – Erotismo, Gênero e Limites da Sexualidade (São Paulo: Companhia das Letras, 2016), Cenas e Queixas – um estudo sobre mulheres, relações violentas e a prática feminista (São Paulo: Paz e Terra/Anpocs, 1993); Viração – experiência de meninos nas ruas (São Paulo: Companhia das Letras, 2000); em coautoria com Cátia Aida da Silva Meninos de Rua e as Instituições (São Paulo: Contexto, 2000). Organizou as seguintes coletâneas: com Adriana Piscitelli e Sergio Carrara (orgs) Sexualidade e Saberes: convenções e fronteiras (Rio de Janeiro: Garamond, 2004); com Guita Grin Debert e Adriana Piscitelli (orgs) Gênero e Distribuição de Justiça: as delegacias de defesa da mulher e a construção das diferenças (Campinas: Pagu, 2006); com Guita Grin Debert e Marcella Beraldo de Oliveira (orgs) Gênero, família e gerações: juizado especial criminal e tribunal do júri (Campinas: Pagu, 2008). Entrevista realizada por Silvia Aguião em maio de 2010 no âmbito do projeto Trajetórias Intelectuais: sexualidade, direitos e políticas na América-Latina, coordenado por Mario Pecheny (Universidad de Buenos Aires e Conicet). O projeto, a partir da realização de entrevistas com intelectuais e ativistas de diversos países latino-americanos, buscou sistematizar o modo particular como se tem conformado uma determinada tradição intelectual e modo de pensar o vínculo entre sexualidade, direitos e política na América Latina
Icephobic Properties of Superhydrophobic Coatings Developed for Aeronautical Applications
Get PDFIce accumulation poses a significant hazard to aviation safety, particularly in cold weather conditions, as it can compromise aerodynamic performance, increase structural weight, and diminish lift, occasionally resulting in severe stall incidents. At present, such risks are managed through the use of energy-demanding active ice protection systems (IPSs), which operate either by inhibiting ice formation (anti-icing) or by removing existing ice (de-icing). Nonetheless, in the context of future sustainable aviation, there is a pressing need to develop IPSs with lower energy requirements. A promising approach involves hybrid IPSs that integrate conventional active systems with passive superhydrophobic or icephobic surface treatments, which are capable of preventing, delaying, or minimizing ice buildup. These systems offer the potential to substantially decrease the energy consumption and consequently the CO2 emissions. Furthermore, in accordance with FAA regulations, active IPSs are not permitted to operate during takeoff and initial flight stages to prevent any reduction in engine thrust. These two reasons emphasize the critical importance of developing efficient coatings that, on the one hand, promote the mobility of water droplets, hereby preventing ice formation, as achieved by superhydrophobic surfaces, and on the other hand, facilitate ice detachment, as required for icephobic performance. In this context, the primary objective of the present work is to emphasize the icephobic properties of two superhydrophobic coatings. To achieve this, an extensive characterization is first conducted, including wettability, Surface Free Energy (SFE), and surface roughness, to confirm their superhydrophobic nature. This is followed by an assessment of their icephobic performance, specifically in terms of ice adhesion strength, with comparisons made against a commercial aeronautical coating. The results revealed a significant reduction in both the wettability and SFE of the developed coatings compared to the reference, along with a marked decrease in ice adhesion strength, thereby demonstrating their icephobic properties. Future activities will focus on the combination of coatings with active IPS in order to assess the energy efficiency under extensive icing conditions where both superhydrophobic and icephobic properties are required
Melt-Crystallizations of α and γ Forms of Isotactic Polypropylene in Propene-Butene Copolymers
Get PDFRandom isotactic propene-butene copolymers (iPPC4) of different stereoregularity have been synthesized with three different homogeneous single center metallocene catalysts having different stereoselectivity. All samples crystallize from the polymerization solution in mixtures of α and γ forms, and the relative amount of γ form increases with increasing concentrations of butene and of rr stereodefects. All samples crystallize from the melt in mixtures of α and γ forms and the fraction of γ form increases with decreasing cooling rate. At high cooling rates, the crystallization of the α form is always favored, even for samples that contain high total concentration of defects that should crystallize in the γ form. The results demonstrate that in iPPs containing significant concentrations of defects, such as stereodefects and comonomeric units, the γ form is the thermodynamically stable form of iPP and crystallizes in selective conditions of very slow crystallization, whereas the α form is the kinetically favored form and crystallizes in conditions of fast crystallization
Primera etapa en el desarrollo de un sistema de información geográfica [SIG] aplicada a la vigilancia epidemiológica
No full textUNIRED: PROYECTO PADRINAZGO PUBLICACIONES PERIODICAS ARGENTINAS. Título (A):
Primera etapa en el desarrollo de un sistema de información geográfica (SIG) aplicada a la
vigilancia epidemiológica: comunicación, pp. 331. Autor Personal (A): Sanchez, J.; Piscitelli, Hernán
Gustavo; Severina, W.; Larriestra, A.; González, J.; Degioani, A.; Giraudo, J. Título Serie - Nº - Vol.:
Revista argentina de producción animal - v. 18, supl. 1 (1998). Idioma - Referencias: es. Notas:
Presentado al 22º Congreso Argentino de Producción Animal. ..
AIQUAV 2020/21 VII Convegno Nazionale dell’Associazione Italiana per gli Studi sulla Qualità della Vita Qualità della vita: ripartire dai territori - Libro dei Contributi Brevi
No full textAtti del VII Convegno Nazionale dell’Associazione Italiana per gli Studi sulla Qualità della Vit
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