46 documents found, page 1 of 5
Development of cement industry, technology, and artistic applications: a histor...
Gueidão, Marta; Bordalo, Rui; Nunes, Sandra; Vieira, EduardaThe development of the cement industry and technology was a significant driver of progress in construction and artistic applications. Between the late 19th and 20th centuries, cement-based mortars and concrete were widely used in both utilitarian and artistic heritage, serving as structural materials and decorative ornaments. This paper presents a historical overview of the Portuguese cement industry within an ...
Strawberry plant as a biomonitor of trace metal air pollution: a citizen scienc...
Gamelas ou Carla A. Gamelas, Carla; Canha, Nuno; Justino, Ana R.; Nunes, Alexandre; Nunes, Sandra; Dionísio, Isabel; Kertesz, ZsofiaA biomonitoring study of air pollution was developed in an urban-industrial area (Seixal, Portugal) using leaves of strawberry plants (Fragaria × ananassa Duchesne ex Rozier) as biomonitors to identify the main sources and hotspots of air pollution in the study area. The distribution of exposed strawberry plants in the area was based on a citizen science approach, where residents were invited to have the plants...
Reactivity of ethyl nitrosoacrylate toward pyrrole, indole and pyrrolo[3,2-c]ca...
Benzi, Alice; Lopes, Susana M. M.; Nunes, Sandra; Giorgi, Gianluca; Bianchi, Lara; Tavani, Cinzia; Pais, Alberto; Petrillo, GiovanniNitrosoalkenes react with 8-methyl-1,6-dihydropyrrolo[3,2-c]carbazole to give both 2- and 3-alkylated products via hetero-Diels-Alder reaction followed by the cycloadduct ring-opening. Quantum chemical calculations, at DFT level of theory, were carried out to investigate the regioselectivity of the cycloaddition of ethyl nitrosoacrylate with 1,6-dihydropyrrolo[3,2-c]carbazoles as well as with pyrrole and indole...
Hardening characterisation of a non-proprietary and more eco-friendly UHPC
Matos, Ana Mafalda; Granja, José Luís Duarte; Nunes, Sandra; Aguiar, J. L. Barroso de; Azenha, MiguelThe current work provides an integrated analysis of autogenous shrinkage, isothermal calorimetry, and modulus of elasticity measurement through ambient response method (EMM-ARM), to characterise the hardening behaviour of a non-proprietary and more eco-friendly ultra-high performance fibre reinforced cementitious composite (UHPFRC). Isothermal calorimetry revealed that induction period ends at 3 h, and the rapi...
“Betão” de ultraelevado desempenho reforçado com fibras metálicas
Matos, Ana Mafalda; Nunes, Sandra; Costa, Carla; Aguiar, J. L. Barroso deNo âmbito da investigação de Doutoramento da primeira autora, foi desenvolvido um UHPFRC mais eco-eficiente para aplicações de reabilitação/ reforço, utilizando materiais disponíveis no mercado Português. O novo UHPFRC, além de incorporar menores quantidades de cimento e sílica de fumo, contou ainda com a incorporação de um subproduto nacional, proveniente da indústria petrolífera. Além disso não foram aplicado...
Multi-level study on UHPFRC incorporating ECat
Abrishambaf, Amin; Pimentel, Mário; Nunes, Sandra; Costa, CarlaThe suitability of a recently developed ultra-high performance fibre reinforced cementitious composite (UHPFRC) incorporating Spent Equilibrium Catalyst, ECat, for structural applications is investigated through a systematic multi-level investigation across micro, meso and composite levels. Scanning electron microscopy, isothermal calorimetry, thermogravimetric analysis, and mercury intrusion porosimetry tests ...
Durability of an UHPFRC under mechanical and chloride loads
Matos, Ana Mafalda; Figueiredo, Stefan Chaves; Nunes, Sandra; Schlangen, Erik; Aguiar, J. L. Barroso deThe high cost of UHPFRC is a limitation on the practical application in real construction projects. However, a very competitive UHPFRC approach is the hybrid structural elements, where thin layers of UHPFRC are employed to rehabilitate/strengthen damage cover concrete. New layers subjected to harsh conditions (loads and/or environmental) can eventually crack under service conditions, changing the local transpor...
Chloride ion penetration into cracked UHPFRC during wetting-drying cycles
Matos, Ana Mafalda; Nunes, Sandra; Figueiredo, Stefan; Schlangen, Erik; Aguiar, J. L. Barroso deThe subject of this paper is the extent to which, during wetting–drying cycles, chloride ions can penetrate Ultra-high-Performance Fibre Reinforced Cementitious Composites (UHPFRC) specimens subjected to combined mechanical and environmental load. Pre-cracking was obtained by subjecting prismatic specimens (40 40 60mm3) to four-point bending until a predefined crack opening displacement (COD) is reached, using ...
Durability of an UHPC containing spent equilibrium catalyst
Matos, Ana Mafalda; Nunes, Sandra; Costa, Carla; Aguiar, JoséUHPC is an advanced cementitious material able to meet the current construction industry challenges regarding structural safety and durability. However, new UHPC formulations with limited shrinkage are still being pursued to reduce residual tensile stresses in the UHPFRC layers, for rehabilitation/strengthening applications. This investigation estimates the durability of a non-proprietary UHPC incorporating a b...
Financial Capacity During a Pandemic Crisis
Santos, Márcia Cadete; Nunes, Sandra; Dominguinhos, Pedro; Mourato, Joaquim; Mata, Carlos; Teixeira, Nuno MiguelThis chapter seeks to provide empirical evidence of the financial shocks that non-profits experienced during the coronavirus disease-19 (COVID-19) pandemic lockdown period. The research included a literature review of the main up-to-date publications to understand non-profits’ financial vulnerabilities. The statistical analyses’ results facilitate a fuller understanding of the impacts that the abrupt loss of cl...