Export 444 results:
Sort by: Author Title Type [ Year  (Desc)]
2022
Díaz, Rafael Sanabria, Brisid Isufi, Leandro Mouta Trautwein, and António Pinho Ramos. "Nonlinear analysis of flat slab-column connections to optimize the use of HPFRC under monotonic vertical loading." Structural Concrete (2022). AbstractWebsite
n/a
Isufi, Brisid, António Pinho Ramos, and Válter Lúcio. "Post-earthquake Performance of a Slab-Column Connection with Punching Shear Reinforcement." Journal of Earthquake Engineering. 26 (2022): 1171-1193. AbstractWebsite
n/a
Ramos, António, Brisid Isufi, Rui Marreiros, Mária Bolešová, and Katarina Gajdošová. "Rational use of HPFRC in slab – column connections under reversed horizontal cyclic loading." Engineering Structures. 270 (2022). AbstractWebsite
n/a
Isufi, Brisid, André Almeida, Rui Marreiros, António Pinho Ramos, and Válter Lúcio. "Slab–column connection punching and ductility improvement methods for seismic response of buildings with flat slabs." Structural Concrete. 23 (2022): 1385-1398. AbstractWebsite
n/a
Torabian, Ala, Brisid Isufi, Davood Mostofinejad, and António Pinho Ramos. "STRENGTHENING OF FLAT SLABS WITH FIBRE REINFORCED POLYMERS USING THE EXTERNALLY BONDED REINFORCEMENT ON GROOVES METHOD: A REVIEW." REHABEND. 2022. 1946-1953. Abstract
n/a
Boillos, J. M., D. Cortina-Gil, J. Benlliure, J. L. Rodr{\'ıguez-Sánchez, H. Alvarez-Pol, L. Atar, T. Aumann, V. V. Avdeichikov, S. Beceiro-Novo, D. Bemmerer, C. A. Bertulani, K. Boretzky, M. J. G. Borge, M. Caamano, C. Caesar, E. Casarejos, W. Catford, J. Cederkäll, M. Chartier, L. Chulkov, E. Cravo, R. N. P. Crespo, I. Dillmann, Diaz P. Fernandez, Z. Elekes, J. Enders, O. Ershova, A. Estrade, F. Farinon, L. M. Fraile, M. Freer, Galaviz D. Redondo, H. Geissel, R. Gernhäuser, P. Golubev, K. Göbel, J. Hagdahl, T. Heftrich, M. Heil, M. Heine, A. Heinz, A. Henriques, M. Holl, A. Hufnagel, A. Ignatov, H. T. Johansson, B. Jonson, J. Kahlbow, N. Kalantar-Nayestanaki, R. Kanungo, A. Kelic-Heil, A. Knyazev, T. Kröll, N. Kurz, M. Labiche, C. Langer, T. Le Bleis, R. Lemmon, S. Lindberg, J. F. D. C. Machado, J. Marganiec, A. Movsesyan, E. Nacher, M. A. Najafi, T. Nilsson, C. Nociforo, V. Panin, S. Paschalis, A. Perea, M. Petri, S. Pietri, R. Plag, R. Reifarth, G. Ribeiro, C. Rigollet, D. M. Rossi, M. Röder, D. Savran, H. Scheit, H. Simon, O. Sorlin, I. J. Syndikus, J. T. Taylor, O. Tengblad, R. Thies, Y. Togano, M. Vandebrouck, P. J. F. Velho, V. Volkov, A. Wagner, F. Wamers, H. Weick, C. Wheldon, G. L. Wilson, J. S. Winfield, P. Woods, D. Yakorev, M. Zhukov, A. Zilges, and K. Zuber. "{Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near $400A$ MeV}." (2022): 1-13. Abstract

Phys. Rev. C 105, 014611 (2022). doi:10.1103/PhysRevC.105.014611

Ménesguen, Y., M. - C. Lépy, Y. Ito, M. Yamashita, S. Fukushima, T. Tochio, M. Polasik, K. Słabkowska, Ł. Syrocki, P. Indelicato, J. P. Gomilsek, J. P. Marques, J. M. Sampaio, J. Machado, P. Amaro, M. Guerra, J. P. Santos, and F. Parente. "{Structure of single KL$^0$-, double KL$^1$-, and triple KL$^2$- ionization in Mg, Al, and Si targets induced by photons, and their absorption spectra}." Radiation Physics and Chemistry. 194 (2022): 110048. AbstractWebsite

Radiation Physics and Chemistry, 194 (2022) 110048. doi:10.1016/j.radphyschem.2022.110048

2021
{Henriques Ferreira}, Sofia, Ana Rovisco, Andreia dos Santos, Hugo Águas, Rui Igreja, Pedro Barquinha, Elvira Fortunato, and Rodrigo Martins. "{Porous ZnO Nanostructures Synthesized by Microwave Hydrothermal Method for Energy Harvesting Applications}." Nanopores. Eds. Sadia Ameen, Shaheer M. Akhtar, and Hyung-Shik Shin. IntechOpen, 2021. Abstract

Abstract Long-haul travel does not constitute an obstacle for tourists to travel and is fast gaining the attention of tourists in new and unique experiences. This study was conducted to identify the long-haul travel motivation by international tourists to Penang. A total of 400 respondents participated in this survey, conducted around the tourist attractions in Penang, using cluster random sampling. However, only 370 questionnaires were only used for this research. Data were analysed using SPSS software 22 version. The findings, ‘knowledge and novelty seeking' were the main push factors that drove long-haul travel by international tourists to Penang. Meanwhile, the main pull factor that attracts long- haul travel by international tourists to Penang was its ‘culture and history'. Additionally, there were partly direct and significant relationships between socio-demographic, trip characteristics and travel motivation (push factors and pull factors). Overall, this study identified the long-haul travel motivations by international tourists to Penang based on socio-demographic, trip characteristics and travel motivation and has indirectly helped in understanding the long-haul travel market particularly for Penang and Southeast Asia. This research also suggested for an effective marketing and promotion strategy in pro- viding useful information that is the key to attract international tourists to travel long distances. Keywords:

Krauth, Julian J., Karsten Schuhmann, Marwan Abdou Ahmed, Fernando D. Amaro, Pedro Amaro, François Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Marc Diepold, Luis M. P. Fernandes, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Jens Hartmann, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Yi-Wei Liu, Jorge Machado, Cristina M. B. Monteiro, Françoise Mulhauser, Boris Naar, Tobias Nebel, François Nez, Joaquim M. F. dos Santos, José Paulo Santos, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Jan Vogelsang, Andreas Voss, Birgit Weichelt, Randolf Pohl, Aldo Antognini, and Franz Kottmann. "Measuring the $\upalpha$-particle charge radius with muonic helium-4 ions." Nature. 589 (2021): 527-531. AbstractWebsite
n/a
Krauth, Julian J., Karsten Schuhmann, Marwan Abdou Ahmed, Fernando D. Amaro, Pedro Amaro, Fran{\c c}ois Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Marc Diepold, Luis M. P. Fernandes, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Jens Hartmann, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Yi-Wei Liu, Jorge Machado, Cristina M. B. Monteiro, Fran{\c c}oise Mulhauser, Boris Naar, Tobias Nebel, Fran{\c c}ois Nez, Joaquim M. F. dos Santos, José Paulo Santos, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Jan Vogelsang, Andreas Voss, Birgit Weichelt, Randolf Pohl, Aldo Antognini, and Franz Kottmann. "{Measuring the $\alpha$-particle charge radius with muonic helium-4 ions}." Nature. 589 (2021): 527-531. AbstractWebsite

The energy levels of hydrogen-like atomic systems can be calculated with great precision. Starting from their quantum mechanical solution, they have been refined over the years to include the electron spin, the relativistic and quantum field effects, and tiny energy shifts related to the complex structure of the nucleus. These energy shifts caused by the nuclear structure are vastly magnified in hydrogen-like systems formed by a negative muon and a nucleus, so spectroscopy of these muonic ions can be used to investigate the nuclear structure with high precision. Here we present the measurement of two 2S–2P transitions in the muonic helium-4 ion that yields a precise determination of the root-mean-square charge radius of the $\alpha$ particle of 1.67824(83) femtometres. This determination from atomic spectroscopy is in excellent agreement with the value from electron scattering1, but a factor of 4.8 more precise, providing a benchmark for few-nucleon theories, lattice quantum chromodynamics and electron scattering. This agreement also constrains several beyond-standard-model theories proposed to explain the proton-radius puzzle2–5, in line with recent determinations of the proton charge radius6–9, and establishes spectroscopy of light muonic atoms and ions as a precise tool for studies of nuclear properties. The 2S–2P transitions in muonic helium-4 ions are measured using laser spectroscopy and used to obtain an $\alpha$-particle charge-radius value five times more precise than that from electron scattering.

dos Santos, Andreia, Filipe Sabino, Ana Rovisco, Pedro Barquinha, Hugo Águas, Elvira Fortunato, Rodrigo Martins, and Rui Igreja. "{Optimization of ZnO Nanorods Concentration in a Micro-Structured Polymeric Composite for Nanogenerators}." Chemosensors. 9 (2021): 27. AbstractWebsite

The growing use of wearable devices has been stimulating research efforts in the development of energy harvesters as more portable and practical energy sources alternatives. The field of piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), especially employing zinc oxide (ZnO) nanowires (NWs), has greatly flourished in recent years. Despite its modest piezoelectric coefficient, ZnO is very attractive due to its sustainable raw materials and the facility to obtain distinct morphologies, which increases its multifunctionality. The integration of ZnO nanostructures into polymeric matrices to overcome their fragility has already been proven to be fruitful, nevertheless, their concentration in the composite should be optimized to maximize the harvesters' output, an aspect that has not been properly addressed. This work studies a composite with variable concentrations of ZnO nanorods (NRs), grown by microwave radiation assisted hydrothermal synthesis, and polydimethylsiloxane (PDMS). With a 25 wt % ZnO NRs concentration in a composite that was further micro-structured through laser engraving for output enhancement, a nanogenerator (NG) was fabricated with an output of 6 V at a pushing force of 2.3 N. The energy generated by the NG could be stored and later employed to power small electronic devices, ultimately illustrating its potential as an energy harvesting device.

Santos, J. P., Mauro Guerra, Jorge M. Sampaio, Gonçalo R. Vília, César A. Godinho, Daniel Pinheiro, Pedro Amaro, José P. Marques, Jorge Machado, Paul Indelicato, Fernando Parente, and José Paulo Santos. "Fundamental Parameters Related to Selenium K\alpha and K\beta Emission X-ray Spectra." Atoms (2021). AbstractWebsite
n/a
Isufi, Brisid, Mariana Rossi, and António Pinho Ramos. "Influence of flexural reinforcement on the seismic performance of flat slab – Column connections." Engineering Structures. 242 (2021). AbstractWebsite
n/a
Isufi, Brisid, and António Pinho Ramos. "A review of tests on slab-column connections with advanced concrete materials." Structures. 32 (2021): 849-860. AbstractWebsite

Advances in concrete technology during the last decades have resulted in the development of materials with enhanced mechanical properties, such as High Strength Concrete (HSC), Fibre Reinforced Concrete (FRC) and Ultra-High Performance Fibre Reinforced Concrete (UHPFRC). The application of these materials in flat slabs, which are a popular structural solution in Reinforced Concrete (RC) buildings worldwide, has the potential of significantly reducing raw material consumption by enabling the design of slenderer and therefore lighter structures. However, flat slabs are susceptible to punching shear failure, which is a complex phenomenon that remains challenging, even though significant efforts have been made to experimentally study it. For advanced concrete materials (HSC, FRC and UHPFRC), the challenge is further accentuated by the continuous and rapid development of these materials. With the purpose of identifying and highlighting gaps in the published literature, a review of tests with HSC, FRC and UHPFRC slab-column connections in non-seismic and seismic loading applications is presented in this paper. It is shown that future research directions in this field include, among others, testing thicker slabs, HSC slabs with higher concrete compressive strength, HSC combined with FRC and several more cases related to seismic loading conditions.

Rossi, Mariana, Brisid Isufi, and António Pinho Ramos. "Seismic behavior of slab-column connections with varying flexural reinforcement ratio." fib Symposium. Vol. 2021-June. 2021. 987-994. Abstract
n/a
Isufi, Brisid, Rui Marreiros, António Pinho Ramos, and Válter Lúcio. "Seismic behaviour of slab-column connections with various punching shear enhancement methods." fib Symposium. Vol. 2021-June. 2021. 978-986. Abstract
n/a
Torabian, Ala, Brisid Isufi, Davood Mostofinejad, and António Pinho Ramos. "Shear and flexural strengthening of deficient flat slabs with post-installed bolts and CFRP composites bonded through EBR and EBROG." Structural Concrete. 22 (2021): 1147-1164. AbstractWebsite

Abstract Fiber reinforced polymer (FRP) composites can be efficient for flexural strengthening of flat slabs if debonding of the FRP is postponed. However, with the increase of the flexural capacity, the flat slab becomes more susceptible to punching shear failure. In this context, four flexural or simultaneous flexural and punching shear retrofitting systems are investigated in this study to strengthen a flexure-deficient flat slab. Externally Bonded Reinforcement on Grooves (EBROG) and externally bonded reinforcement (EBR) methods are used for flexural strengthening in two cases: slabs without punching shear reinforcement and with post-installed shear bolts as shear reinforcement. According to the results, flexural strengthening of the slab using the EBR and EBROG techniques increased its load capacity by 12% and 21%, respectively. Simultaneous flexural and shear strengthening of the slab using the EBROG technique was the most effective, leading to a 57% enhancement of the load capacity. For specimens whose failure was governed by punching, comparing the results with code predictions showed that Eurocode and ACI (and the respective guide documents fib bulletin 90 and ACI 440.2R) overestimated the capacity of these specimens. In cases where failure was governed by flexure, a simple application of the yield line theory predicted reasonably well the load capacity of the specimens.

{Guerra, Mauro, Jorge Sampaio, Gon{\c c}alo V{\'ılia, César Godinho, Daniel Pinheiro, Pedro Amaro, José Marques, Jorge Machado, Paul Indelicato, Fernando Parente, and José Santos. "{Fundamental Parameters Related to Selenium K$\alpha$ and K$\beta$ Emission X-ray Spectra}." Atoms. 9 (2021): 8-10. AbstractWebsite

We present relativistic ab initio calculations of fundamental parameters for atomic selenium, based on the Multiconfiguration Dirac-Fock method. In detail, fluorescence yields and subshell linewidths, both of K shell, as well as K$\beta$ to K$\alpha$ intensity ratio are provided, showing overall agreement with previous theoretical calculations and experimental values. Relative intensities were evaluated assuming the same ionization cross-section for the K-shell hole states, leading to a statistical distribution of these initial states. A method for estimating theoretical linewidths of X-ray lines, where the lines are composed by a multiplet of fine-structure levels that are spread in energy, is proposed. This method provides results that are closer to K$\alpha$1,2 experimental width values than the usual method, although slightly higher discrepancies occur for the K$\beta$1,3 lines. This indicates some inaccuracies in the calculation of Auger rates that have a higher contribution for partial linewidths of the subshells involved in the K$\beta$1,3 profile. Apart from this, the calculated value of K$\beta$ to K$\alpha$ intensity ratio, which is less sensitive to Auger rates issues, is in excellent agreement with recommended values.

Boretzky, K., I. Gasparic, M. Heil, J. Mayer, A. Heinz, C. Caesar, D. Kresan, H. Simon, H. T. Törnqvist, D. Körper, G. Alkhazov, L. Atar, T. Aumann, D. Bemmerer, S. V. Bondarev, L. T. Bott, S. Chakraborty, M. I. Cherciu, L. V. Chulkov, M. Ciobanu, U. Datta, E. De Filippo, C. A. Douma, J. Dreyer, Z. Elekes, J. Enders, D. Galaviz, E. Geraci, B. Gnoffo, K. Göbel, V. L. Golovtsov, Gonzalez D. Diaz, N. Gruzinsky, T. Heftrich, H. Heggen, J. Hehner, T. Hensel, E. Hoemann, M. Holl, A. Horvat, Á. Horváth, G. Ickert, Jelavić D. Malenica, H. T. Johansson, B. Jonson, J. Kahlbow, N. Kalantar-Nayestanaki, A. Kelic-Heil, M. Kempe, K. Koch, N. G. Kozlenko, A. G. Krivshich, N. Kurz, V. Kuznetsov, C. Langer, Y. Leifels, I. Lihtar, B. Löher, J. Machado, N. S. Martorana, K. Miki, T. Nilsson, E. M. Orischin, E. V. Pagano, S. Pirrone, G. Politi, P. M. Potlog, A. Rahaman, R. Reifarth, C. Rigollet, M. Röder, D. M. Rossi, P. Russotto, D. Savran, H. Scheit, F. Schindler, D. Stach, E. Stan, Stomvall J. Gill, P. Teubig, M. Trimarchi, L. Uvarov, M. Volknandt, S. Volkov, A. Wagner, V. Wagner, S. Wranne, D. Yakorev, L. Zanetti, A. Zilges, K. Zuber, and R. 3B. collaboration. "{NeuLAND: The high-resolution neutron time-of-flight spectrometer for R3B at FAIR}." Nuclear Inst. and Methods in Physics Research, A. 1014 (2021): 165701. AbstractWebsite

Nuclear Inst. and Methods in Physics Research, A, 1014 (2021) 165701. doi:10.1016/j.nima.2021.165701

2020
Ito, Y., T. Tochio, M. Yamashita, S. Fukushima, A. M. Vlaicu, J. P. Marques, J. M. Sampaio, M. Guerra, J. P. Santos, Ł. Syrocki, K. Słabkowska, E. WÈ©der, M. Polasik, J. Rzadkiewicz, P. Indelicato, Y. Ménesguen, M.-Ch. Lépy, and F. Parente. "Structure of K$\upalpha$1,2- and K$\upbeta$1,3-emission x-ray spectra for Se, Y, and Zr." Physical Review A. 102 (2020). AbstractWebsite
n/a
Martins, L., P. Amaro, S. Pessanha, M. Guerra, J. Machado, M. L. Carvalho, J. P. Santos, and P. Indelicato. "{Overview and calculation of X-ray K-shell transition yields for comprehensive data libraries}." X-Ray Spectrom.. 62 (2020): 63-26. AbstractWebsite

The simulation of atomic relaxation relies on data libraries with tabulated partial fluorescence yield values of radiative transitions, commonly derived from the Evaluated Atomic Data Library (EADL)....

Rovisco, Ana, Andreia dos Santos, Tobias Cramer, Jorge Martins, Rita Branquinho, Hugo Águas, Beatrice Fraboni, Elvira Fortunato, Rodrigo Martins, Rui Igreja, and Pedro Barquinha. "{Piezoelectricity Enhancement of Nanogenerators Based on PDMS and ZnSnO 3 Nanowires through Microstructuration}." ACS Applied Materials & Interfaces. 12 (2020): 18421-18430. AbstractWebsite

The current trend for smart, self-sustainable, and multifunctional technology demands for the development of energy harvesters based on widely available and environmentally friendly materials. In this context, ZnSnO3 nanostructures show promising potential because of their high polarization, which can be explored in piezoelectric devices. Nevertheless, a pure phase of ZnSnO3 is hard to achieve because of its metastability, and obtaining it in the form of nanowires is even more challenging. Although some groups have already reported the mixing of ZnSnO3 nanostructures with polydimethylsiloxane (PDMS) to produce a nanogenerator, the resultant polymeric film is usually flat and does not take advantage of an enhanced piezoelectric contribution achieved through its microstructuration. Herein, a microstructured composite of nanowires synthesized by a seed-layer free hydrothermal route mixed with PDMS (ZnSnO3@PDMS) is proposed to produce nanogenerators. PFM measurements show a clear enhancement of d33 for single ZnSnO3 versus ZnO nanowires (23 ± 4 pm/V vs 9 ± 2 pm/V). The microstructuration introduced herein results in an enhancement of the piezoelectric effect of the ZnSnO3 nanowires, enabling nanogenerators with an output voltage, current, and instantaneous power density of 120 V, 13 $μ$A, and 230 $μ$W·cm-2, respectively. Even using an active area smaller than 1 cm2, the performance of this nanogenerator enables lighting up multiple LEDs and other small electronic devices, thus proving great potential for wearables and portable electronics.

dos Santos, Raquel, Inês Iria, Ana M. Manuel, Ana P. Leandro, Catarina A. C. Madeira, Joao Goncalves, Ana Luísa Carvalho, and Ana Cecília Roque. "Magnetic Precipitation: A New Platform for Protein Purification." Biotechnology JournalBiotechnology Journal. n/a.n/a (2020): 2000151. AbstractWebsite

One of the trends in downstream processing comprises the use of ?anything-but-chromatography? methods to overcome the current downfalls of standard packed-bed chromatography. Precipitation and magnetic separation are two techniques already proven to accomplish protein purification from complex media, yet never used in synergy. With the aim to capture antibodies directly from crude extracts, a new approach combining precipitation and magnetic separation was developed and named as affinity magnetic precipitation. A precipitation screening, based on the Hofmeister series, and a commercial precipitation kit were tested with affinity magnetic particles to assess the best condition for antibody capture from human serum plasma and clarified cell supernatant. The best conditions were obtained when using PEG3350 as precipitant at 4°C for 1h, reaching 80% purity and 50% recovery of polyclonal antibodies from plasma, and 99% purity with 97% recovery yield of anti-TNFα mAb from cell supernatants. These results show that the synergetic use of precipitation and magnetic separation can represent an alternative for the efficient capture of antibodies. This article is protected by copyright. All rights reserved

Torabian, Ala, Brisid Isufi, Davood Mostofinejad, and António Pinho Ramos. "Shear and flexural strengthening of deficient flat slabs with post-installed bolts and CFRP composites bonded through EBR and EBROG." Structural Concrete. n/a (2020). AbstractWebsite

Abstract Fiber reinforced polymer (FRP) composites can be efficient for flexural strengthening of flat slabs if debonding of the FRP is postponed. However, with the increase of the flexural capacity, the flat slab becomes more susceptible to punching shear failure. In this context, four flexural or simultaneous flexural and punching shear retrofitting systems are investigated in this study to strengthen a flexure-deficient flat slab. Externally Bonded Reinforcement on Grooves (EBROG) and externally bonded reinforcement (EBR) methods are used for flexural strengthening in two cases: slabs without punching shear reinforcement and with post-installed shear bolts as shear reinforcement. According to the results, flexural strengthening of the slab using the EBR and EBROG techniques increased its load capacity by 12% and 21%, respectively. Simultaneous flexural and shear strengthening of the slab using the EBROG technique was the most effective, leading to a 57% enhancement of the load capacity. For specimens whose failure was governed by punching, comparing the results with code predictions showed that Eurocode and ACI (and the respective guide documents fib bulletin 90 and ACI 440.2R) overestimated the capacity of these specimens. In cases where failure was governed by flexure, a simple application of the yield line theory predicted reasonably well the load capacity of the specimens.

Penalva, H., M. Ivette Gomes, F. Caeiro, and M. Manuela Neves. "A couple of non reduced bias generalized means in extreme value theory: An asymptotic comparison." Revstat Statistical Journal. 18 (2020): 281-298. Abstract
n/a