62 research outputs found
Towards the valorization of Cumbre Vieja volcanic ash - Production of alternative cements
No full text[EN] One of the most critical issues after a volcanic eruption is managing damaged infrastructure and human health. This study aims to promote the valorization of non-weathered volcanic ash (VA) from the Cumbre Vieja volcano (La Palma Island ¿ Spain) in the production of alternative cements. A detailed study related to the characterization of VA was performed, and its use in the production of alkali-activated cements is proposed. Promising results, achieving about 80 MPa in compression, indicated that using a cementing material based on VA could be a fascinating solution for the VA valorization and the reconstruction of the affected infrastructure of La Palma Island, especially in producing prefabricated elements.Thanks are given to the Government Presidency of the Canary Islands, the Spanish Military Emergency Unit (UME), and the General Directorate for Coordination of Action of the Generalitat Valenciana Government. Also, to the Electron Microscopy Service of the Universitat Politecnica de Val`encia and Sonia Cortes from Ediciones Fruit Today, S. L. to provide photos of the Cumbre Vieja volcano and affected zones (Figure b and suppl. Figure). Finally, M.M. Tashima wishes to thank the Spanish Ministry of Universities and the Universitat Politecnica de Valencia for the grant "Maria Zambrano for attraction of international talent", funded by European Union-Next Generation.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2023). Towards the valorization of Cumbre Vieja volcanic ash - Production of alternative cements. Construction and Building Materials. 370:1-8. https://doi.org/10.1016/j.conbuildmat.2023.130635S1837
New insights on understanding the Portland cement hydration using electrical impedance spectroscopy
No full text[EN] This study aimed to bring new perspectives and understandings, as well as to elucidate the behavior of Portland cement hydration through electrical conductivity curves obtained by impedance spectroscopy (IS). The IS measurement was performed on Portland cement paste with w/c ratio of 0.40 up to 28 curing days. According to the results, based on the inflection points of its respective derivative, the electrical conductivity curve of Portland cement paste can be subdivided into eight different regions. A new region (region IV) in the acceleration period, characterized by the resume of dissolution reactions and microstructure formation with the paste in a semi-fluid
state, was established. Moreover, a shoulder observed in region VI was attributed to the formation of AFt phases from the reduction of CaSO4, and secondary reactions of ionic release in the pore network. Hence, new insights on the electrical conductivity curve of Portland cement paste are reported confirming the IS as a sensitive and promising technique.The authors are grateful to Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brazil (CAPES) - (Finance Code 001) and to Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESP (Project 2020/16325-0 and CEPID-CDMF 2013/07296-2) for the financial support and scholarship. Finally, M.M. Tashima wishes to thank the Spanish Ministry of Universities and the Universitat Politecnica de Valencia for the grant "Maria Zambrano for attraction of international talent" funded by European Union -Next generation.Borboletto, M.; Sanches, A.; Santos, J.; Da Silva, R.; Mitsuuchi Tashima, M.; Paya Bernabeu, JJ.; Soriano Martinez, L.... (2023). New insights on understanding the Portland cement hydration using electrical impedance spectroscopy. Construction and Building Materials. 407. https://doi.org/10.1016/j.conbuildmat.2023.133566S40
An imperial diet: from cacao to coconuts – representing edible bodies in the Americas from the eighteenth century to the present
No full textThis dissertation endeavors to prove through a series of visual mediations that the alimentary tract signifies a gastropoetical dialectic between the eater and the eaten. Alimentary discourse is capable of developing a visual language that illustrates the interiority of appetites of empire through the politics of provender. In this study sugar, cacao, pineapples, and coconuts operate as a lens to view the scaffolding of social and artistic strategies. This project is committed to the excavation of image construction, the visual representation of the African Diaspora in the Americas, and understanding the formation of gastronomical narratives through colonial discourse. Anthropologist Sidney W. Mintz suggests that anthropology has the capabilities to answer the outside and inside meanings of food pathways; but so far it has not done so. This dissertation will be able to offer insight into these issues. In a way, this work calls out what I consider obvious omissions regarding the connections between art history, the visual archive, and tropical food pathways by clearly articulating the power of these foods to transform cultures of vision and the induction of a modern world system. Ultimately, my dissertation offers a critical study of race, gender, sexuality, transnational, and transhistorical food pathways.Ph.D.Includes bibliographical referencesby Tashima Thoma
Spent FCC catalyst for preparing alkali-activated binders: an opportunity for a high-degree valorization
No full textSpent FCC catalyst is a waste from the petrochemical industry which has excellent pozzolanic properties, containing more than 90% silica and alumina. Its similarity to metakaolin creates interesting prospects for its use in the production of alkali-activated binders. In this study, the alkali activation of this residue, spent FCC catalyst, through mixtures with alkali hydroxide and silicate solutions (both sodium and potassium) has been carried out. The alkali cation had an important role in the nature of AA-FCC pastes: some differences in the mass loss in the thermogravimetric tests and in the X-ray mineral characterization were found. No significant differences in compressive strength were observed for mortars cured for 3 days in several conditions: room temperature and 65ºC. Prepared AA-FCC mortars had a compressive strength of about 65-70 MPa. Microstructural studies showed that an amorphous, dense and compact microstructure was obtained, independent of the activating solution and curing condition.Mitsuuchi Tashima, M.; Soriano Martinez, L.; Akasaki, JL.; Castaldelli, V.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2014). Spent FCC catalyst for preparing alkali-activated binders: an opportunity for a high-degree valorization. Key Engineering Materials. 600:709-716. doi:10.4028/www.scientific.net/KEM.600.709S709716600WBCSD – World Business Council for Sustainable Development, Cement industry energy and CO2 performance – Getting numbers right, WBCSD editor, (2009).S. Berger, C.C.D. Coumes, P. le Bescop, D. Damidot, Influence of a thermal cycle at early age on the hydration of calcium sulphoaluminate cements with variable gypsum contents, Cem. Concr. Res. 41-3 (2011) 149-160.I. García-Díaz, J.G. Palomo, F. Puertas, Belite cements obtained from ceramic wastes and the mineral pair CaF2/CaSO4, Cem. Concr. Comp. 33-10 (2011) 1063-1070.M.M. Tashima, L. Soriano, M.V. Borrachero, J. Monzó, C.R. Cheeseman, J. Payá, Alkali activation of vitreous calcium aluminosilicate derived from glass fiber waste, J. Sust. Cem-Based Mater. 1-3 (2012) 83-93.J. Payá, M.V. Borrachero, J. Monzó, L. Soriano, M.M. Tashima, A new geopolymeric binder from hydrated-carbonated cement, Mater. Lett. 74 (2012) 223-225.C. Shi, A. Fernández-Jiménez, A. Palomo, New cements for the 21st century: The pursuit of an alternative to Portland cement, Cem. Concr. Res. 41 (2011) 750-763.P. Duxson, A. Fernández-Jiménez, J.L. Provis, G.C. Lukey, A. Palomo, J.S.J. van Deventer, Geopolymer technology: the current state of the art, J. Mater. Sci. 42 (2007) 2917-2933.A. Fernández-Jiménez, A. Palomo, M. Criado, Microstructure development of alkali-activated fly ash cement: a descriptive model, Cem. Concr. Res. 35 (2005) 1204-1209.J. Payá, J. Monzó, M.V. Borrachero, Fluid catalytic cracking catalyst residue (FC3R) An excellent mineral by-product for improving early-strength development of cement mixtures, Cem. Concr. Res. 29 (1999) 1773-1779.J. Payá, M.V. Borrachero, J. Monzó, L. Soriano, Estudio del comportamiento de diversos residuos de catalizadores de craqueo catalítico (FCC) en cemento Portland, Mat. Construc. 59-296 (2009) 37-52.M.M. Tashima, J.L. Akasaki, V.N. Castaldelli, L. Soriano, J. Monzó, J. Payá, M.V. Borrachero, New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC), Mater. Lett. 80 (2012) 50-52.A.V. McCormick, A.T. Bell, The solution chemistry of zeolite precursors, Catal. Rev. Sci. Eng. 31 (1989) 97-127
Influence of sugar cane straw ash in metakaolin-based geopolymers
No full text[EN] The present investigation studied the use of agro-industrial waste, sugar cane straw ash (SCSA), to partially replace commercial metakaolin (MK) in geopolymers (0 %, 15 %, 30 %, and 45 % percentages of substitution by mass). The study presented solid precursors characterization, microstructural studies of pastes, and compressive strength of mortars assessed between 1 and 90 days of curing at 25 degrees C. The chemical composition of MK was mainly based on SiO2 2 (54.1 wt%) and Al2O3 2 O 3 (35.9 wt%), and SCSA was mainly composed of SiO2 2 (58.6 wt%). Microstructural studies of pastes showed that occurred a formation of N-A-S-H amorphous reaction products and no crystalline phases were formed; SCSA contributed to the formation of geopolymer reaction products as a secondary role to the main reaction of MK; the presence of SCSA slightly increased the porosity and did not excessively modify the pore distribution; and the pastes with SCSA presented a heterogeneous microstructure. The compressive strength of mortars reached values over 50 MPa after 90 days of curing. Therefore, SCSA was a sustainable replacement for MK in producing geopolymers.This work was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [grant number 153164/2016-6] for scholarship to J.C.B. Moraes; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [grant number 401724/2013-1] ; and the "Ministerio de Educacion, Cultura y Deporte" of Spain ("Cooperacion Interuniversitaria" program with Brazil) [grant number PHB-2011-0016-PC] . Finally, M.M. Tashima wishes to thank the Spanish Ministry of Universities and the Universitat Politecnica de Valencia for the grant "Maria Zambrano for attraction of international talent", funded by European Union-Next Generation.Moraes, J.; Moraes, M.; Batista, J.; Akasaki, J.; Font, A.; Tashima, M.; Soriano Martinez, L.... (2024). Influence of sugar cane straw ash in metakaolin-based geopolymers. Construction and Building Materials. 444. https://doi.org/10.1016/j.conbuildmat.2024.137835S44
Avaliação psicológica de migrantes internacionais [Psychological assessment of international migrants]
No full textPessoas vulneráveis são aquelas cujas condições políticas, sociais e econômicas limitam seus direitos enquanto cidadãos. A vulnerabilidade psicossocial, por sua vez, refere-se ao sofrimento psíquico desencadeado pela exposição a riscos como a pobreza, a doença, a vivência de traumas, a exposição à violência, a privação de direitos civis básicos, entre tantos outros. Infelizmente, os contextos de vulnerabilidade psicossocial são bastante comuns na sociedade brasileira, exigindo da Psicologia, um posicionamento político e, sobretudo, tecnicamente qualificado.
Destinado aos psicólogos e estudantes de Psicologia, esse livro tem por objetivo apresentar a prática da avaliação psicológica aplicada a pessoas em diferentes situações de vulnerabilidade psicossocial. Pretende discutir os procedimentos de avaliação considerando as especificidades e limitações de cada contexto abordando, de forma clara e didática, as técnicas e recursos possíveis para a compreensão de cada demanda
Effect of wastes from sugar cane industry on the mechanical and hydraulic properties of pervious concrete
No full text[EN] Pervious concrete is a construction material widely used in pervious
pavements. Pozzolanic materials replacing partially Portland cement can improve mechanical and hydraulic issues associated with the use of pervious concrete. This paper reports the use of wastes from the sugar cane industry (sugar cane bagasse ash and sugar cane straw ash) and their influence on the mechanical and hydraulic properties of pervious concrete for different binder:aggregate mass ratio (1:3.5, 1:4.0, 1:4.5, 1:5.0). The assessed pervious concrete achieved a compressive strength in the range 7.4¿14.2 MPa, a total porosity between 26.4 and 32.4% and an infiltration rate of 0.6¿1.3 cm/s.The authors would like to acknowledge the FEIS/UNESP microscopy service and MineracAo Grandes Lagos Ltda by supplying aggregates. The first author would like to acknowledge CoordenacAo de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) for the scholarship.Da Silva, R.; Bortoletto, M.; Bigotto, S.; Akasaki, JL.; Soriano Martinez, L.; Mitsuuchi Tashima, M. (2022). Effect of wastes from sugar cane industry on the mechanical and hydraulic properties of pervious
concrete. Road Materials and Pavement Design. 23(9):1981-1998. https://doi.org/10.1080/14680629.2021.1927156S1981199823
A 100% waste-based alkali-activated material by using olive-stone biomass ash (OBA) and blast furnace slag (BFS)
No full text[EN] This study presents the use of olive-stone biomass ash (OBA) as an alkali source in alkali-activated materials (AAM) based on blast furnace slag (BFS). The OBA was physically and chemically characterized. It presented high K2O and CaO contents, and yielded high alkalinity in water medium. The newly designed OBA + BFS mixes (a 100% waste-based AAM) reached a compressive strength of 30 MPa after 7 days of curing at 65 ºC, which was higher than for BFS activated with KOH solution. Thermogravimetric studies showed the formation of C-S-H/(C,K)-A-S-H gels and hydrotalcite. The OBA presented excellent performance as a component in AAM and a good valorisation was achievedFont-Pérez, A.; Soriano Martínez, L.; Moraes, J.; Tashima, M.; Monzó Balbuena, JM.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2017). A 100% waste-based alkali-activated material by using olive-stone biomass ash (OBA) and blast furnace slag (BFS). Materials Letters. 203:46-49. https://doi.org/10.1016/j.matlet.2017.05.129S464920
Eucalyptus ash from biomass combustion for energy as a partial replacement for sand in mortars: a sustainable alternative
No full textThis study investigated the use of eucalyptus ash (EA) as a partial replacement for sand in mortar properties. The EA underwent particle size reclassification (ERA) to match the particle size distribution of the sand used in the mortar mixtures. Properties of the mortar in both fresh and hardened states were evaluated, as well as the microstructure of the mortars, with substitution levels of 15%, 30%, and 50% of sand by ERA. The experimental program included the physical and chemical characterization of eucalyptus ash and its derivatives, including X-ray diffraction (XRD), scanning electron microscopy (SEM), consistency index, density in fresh and hardened states, capillary absorption, immersion absorption, and compressive strength. The results indicated that EA has a crystalline nature with high hygroscopicity. The reclassification process significantly reduced carbonate and pulverulent material content in the ash. Mortars with ERA tended to have more voids and absorb more water than the control. However, the compressive strength of the mortars with ERA showed similar values to the control at 7 and 28 days of curing, reaching values of 48.55 ± 0.77 MPa and 46.44 (± 0.44) MPa for 30% and 50% of ERA substitution at 28 days, respectively. Therefore, ERA provided the production of mortars with higher sustainability, with replacements of 15% and 30% being the most recommended, without significant loss in properties in the fresh and hardened state of the mortar.This study was financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) – Finance Code 001. M.M. Tashima wishes to thanks the Ramón y Cajal grant RYC2023-045079-I, funded by MCIU/AEI/10.13039/501100011033 and by FSE+
New insights on the development of sustainable pervious concrete using sand replacing paste volume - technical, economical, and environmental analysis
No full textSeveral studies in the literature report the use of fine aggregates in pervious concrete. In all reported cases, pervious concrete (PC) consistently demonstrates a reduction in the total porosity, leading to changes in hydraulic and mechanical properties. This could compromise the desired material efficiency, leading to a reduction in its environmental efficiency. In this laboratorial-scale study, the feasibility of producing sustainable PC by partially replacing paste volume by sand, in percentages up to 59%, without significant alteration in the total porosity was assessed. A fixed-porosity methodology was employed, adjusting cement paste volume to maintain constant total porosity across mixtures, regardless of sand incorporation levels. This methodological advance could provide new insights into the production of sustainable PC, and highlights the precise effect of sand on its mechanical and hydraulic properties, as well as its economic and environmental aspects. Obtained results demonstrated the fixed-porosity methodology could be considered a powerful tool to evaluate the effect of fine aggregates in PC, contributing to the development of more sustainable solutions. Specifically, the feasibility of producing PC with sand replacing paste volume up to 38% without changes in the total porosity was demonstrated. The OPC consumption was reduced by approximately 100 kg/m3, costs were reduced up to 25% while maintaining compressive strength and GHG emissions were reduced between 16.7-30-7% when compared to conventional PC.This study was financed in part by the Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001. The authors would like to acknowledge Mineraçao Grandes Lagos Ltda by supplying aggregates. R.G. da Silva wishes to thanks the Conselho Nacional de Desenvolvimento Científico e Tecnologico (CNPq) by scholarship PDJ process n◦ 151502/2024-2. Finally, M.M. Tashima wishes to thanks the Ramon y Cajal grant RYC2023-045079-I, funded by MCIU/AEI/10.13039/ 501100011033 and by FSE+
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