39 documents found, page 1 of 4
A multidisciplinary engineering-based approach for tunnelling strengthening wit...
Barros, Joaquim; Costelha, Hugo; Bento, David; Brites, Nelson; Luís, Rui; Patrício, Hugo; Cunha, Vítor M.C.F.; Bento, Luís; Miranda, TiagoThis paper describes the relevant research activities that are being carried out on the development of a novel shotcrete technology capable of applying, autonomously and in real time, fibre reinforced shotcrete (FRS) with tailored properties regarding the optimum structural strengthening of railway tunnels (RT). This technique allows to apply fibre reinforced concrete (FRC) of strain softening (SSFRC) and strai...
A multidisciplinary engineering-based approach for tunnelling strengthening wit...
Barros, Joaquim A. O.; Costelha, Hugo; Bento, David; Brites, Nelson; Luís, Rui; Patrício, Hugo; Cunha, Vitor; Bento, Luís; Miranda, Tiago; Coelho, PauloThis paper describes the relevant research activities that are being carried out on the development of a novel shotcrete technology capable of applying, autonomously and in real time, fibre reinforced shotcrete (FRS) with tailored properties regarding the optimum structural strengthening of railway tunnels (RT). This technique allows to apply fibre reinforced concrete (FRC) of strain softening (SSFRC) and strai...
Manual and automatic image analysis segmentation methods for blood flow studies...
Carvalho, Violeta Meneses; Gonçalves, Inês M.; Souza, Andrews Victor Almeida; Souza, Maria Sabrina; Bento, David; Ribeiro, J.E.; Lima, Rui A.In blood flow studies, image analysis plays an extremely important role to examine raw data obtained by high-speed video microscopy systems. This work shows different ways to process the images which contain various blood phenomena happening in microfluidic devices and in microcirculation. For this purpose, the current methods used for tracking red blood cells (RBCs) flowing through a glass capillary and techni...
Manual and automatic image analysis segmentation methods for blood flow studies...
Carvalho, Violeta Meneses; Gonçalves, Inês M.; Souza, Andrews Victor Almeida; Souza, Maria Sabrina Veira Miranda Palva; Bento, David; Ribeiro, João E.In blood flow studies, image analysis plays an extremely important role to examine raw data obtained by high-speed video microscopy systems. This work shows different ways to process the images which contain various blood phenomena happening in microfluidic devices and in microcirculation. For this purpose, the current methods used for tracking red blood cells (RBCs) flowing through a glass capillary and techni...
Bubbles moving in blood flow in a microchannel network: the effect on the local...
Bento, David; Lopes, Sara; Maia, Inês; Lima, Rui Alberto Madeira Macedo; Miranda, João M.Air inside of blood vessels is a phenomenon known as gas embolism. During the past years, studies have been performed to assess the influence of air bubbles in microcirculation. In this study, we investigated the flow of bubbles in a microchannel network with several bifurcations, mimicking part of a capillary system. Thus, two working fluids were used, composed by sheep red blood cells (RBCs) suspended in a De...
Blood flow of bubbles moving in microchannels with bifurcations
Bento, David; Lopes, Sara Helena Carvalho; Maia, Inês; Pereira, Ana I.; Fernandes, Carla S.; Miranda, João Mário; Lima, Rui A.The gas embolism is a well-known phenomenon. Previous studies have been performed to understand the formation, the behavior and the influence of air bubbles in microcirculation. This study aims to investigate the flow of bubbles in a microchannel network with bifurcations. For that purpose, a microchannel network was fabricated by soft lithography. The working fluids used were composed by sheep red blood cells ...
In vitro blood flow visualizations and cell-free layer (CFL) measurements in a ...
Bento, David; Fernandes, Carla S.; Miranda, João Mário; Lima, Rui A.Microvascular networks are not simple straight microchannels but rather complex geometries composed by successive asymmetric divergent and convergent bifurcations. Despite the extensive research work in this field, still lack of knowledge about the blood flow behavior in microvascular networks. The current study applies the most current advanced visualization and microfabrication techniques to provide further i...
Deformation of red blood cells, air bubbles and droplets in microfluidic device...
Bento, David; Rodrigues, Raquel Oliveira; Faustino, Vera; Pinho, Diana; Fernandes, Carla S.; Pereira, Ana I.; Garcia, Valdemar; Miranda, João MárioTechniques, such as micropipette aspiration and optical tweezers, are widely used to measure cell mechanical properties, but are generally labor-intensive and time-consuming, typically involving a difficult process of manipulation. In the past two decades, a large number of microfluidic devices have been developed due to the advantages they offer over other techniques, including transparency for direct optical a...
Visualization and measurement of the cell-free layer (CFL) in a microchannel ne...
Bento, David; Fernandes, Carla S.; Pereira, Ana I.; Miranda, João Mário; Lima, Rui A.In the past years, in vitro blood studies have revealed several significant hemodynamic phenomena that have played a key role in recent developments of biomedical microdevices for cells separation, sorting and analysis. However, the blood flow phenomena happening in complex geometries, such as microchannel networks, have not been fully understood. Thus, it is important to investigate in detail the blood flow be...
Deformation of red blood cells, air bubbles, and droplets in microfluidic devic...
Bento, David; Rodrigues, Raquel O.; Faustino, Vera; Pinho, Diana; Fernandes, Carla S.; Pereira, Ana I.; Garcia, Valdemar; Miranda, João M.Techniques, such as micropipette aspiration and optical tweezers, are widely used to measure cell mechanical properties, but are generally labor-intensive and time-consuming, typically involving a difficult process of manipulation. In the past two decades, a large number of microfluidic devices have been developed due to the advantages they offer over other techniques, including transparency for direct optical ...