Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
1,492
result(s) for
"Soares, Francisco"
Sort by:
InP-Based Foundry PICs for Optical Interconnects
2019
This paper describes a fabrication process for realizing Indium-Phosphide-based photonic-integrated circuits (PICs) with a high level of integration to target a wide variety of optical applications. To show the diversity in PICs achievable with our open-access foundry process, we illustrate two examples: a fully-integrated 20 Gb/s dual-polarization electro-absorption-modulated laser, and a balanced detector composed of avalanche photodiodes for detection of 28 Gb/s optical signals. On another note, datacenters are increasingly relying on hybrid integration of PICs from different technology platforms to increase transmission capacity, while simultaneously lowering cost, size, and power consumption. Several technology platforms require surface coupling rather than the traditional edge coupling to couple the light from one PIC to another. To accommodate the surface-coupling approach in our integration platform, we have developed a strategy to transfer the following optical Input/Output devices into our fabrication process: grating couplers, and vertical mirrors. In addition, we introduced etched facets into the process to improve the usability of our edge-coupling elements. We believe that the additional flexibility in Input/Output interfacing combined with the integration of multiple devices onto one PIC to reduce the number of PIC-to-PIC alignments can contribute significantly to the development of compact, low-cost, and high-performance datacenter modules.
Journal Article
Optimization of bacterial nanocellulose fermentation using recycled paper sludge and development of novel composites
by
Ferreira, Eugénio C.
,
Fernandes, Marta
,
Souto, António Pedro
in
Acids
,
Analysis
,
Biomedical and Life Sciences
2019
In this work, recycled paper sludge (RPS), composed of non-recyclable fibres, was used as a carbon source for bacterial nanocellulose (BNC) production. The biomass was enzymatically hydrolysed with Cellic CTec 2 to produce a sugar syrup with 45.40 g/L glucose, 1.69 g/L cellobiose and 2.89 g/L xylose. This hydrolysate was used for the optimization of BNC fermentation by static culture, using
Komagataeibacter xylinus
ATCC 700178
,
through response surface methodology (RSM). After analysis and validation of the model, a maximum BNC yield (5.69 g/L, dry basis) was obtained using 1.50% m/v RPS hydrolysate, 1.0% v/v ethanol and 1.45% m/v yeast extract/peptone (YE/P). Further, the BNC obtained was used to produce composites. A mixture of an amino-PolyDiMethylSiloxane-based softener, polyethyleneglycol (PEG) 400 and acrylated epoxidized soybean oil (AESO), was incorporated into the BNC membranes through an exhaustion process. The results show that BNC composites with distinct performances can be easily designed by simply varying the polymers percentage contents. This strategy represents a simple approach towards the production of BNC and BNC-based composites.
Journal Article
End-to-End Detection of a Landing Platform for Offshore UAVs Based on a Multimodal Early Fusion Approach
by
Claro, Rafael Marques
,
Pinto, Andry Maykol
,
Neves, Francisco Soares
in
Accuracy
,
Cameras
,
computer vision
2023
A perception module is a vital component of a modern robotic system. Vision, radar, thermal, and LiDAR are the most common choices of sensors for environmental awareness. Relying on singular sources of information is prone to be affected by specific environmental conditions (e.g., visual cameras are affected by glary or dark environments). Thus, relying on different sensors is an essential step to introduce robustness against various environmental conditions. Hence, a perception system with sensor fusion capabilities produces the desired redundant and reliable awareness critical for real-world systems. This paper proposes a novel early fusion module that is reliable against individual cases of sensor failure when detecting an offshore maritime platform for UAV landing. The model explores the early fusion of a still unexplored combination of visual, infrared, and LiDAR modalities. The contribution is described by suggesting a simple methodology that intends to facilitate the training and inference of a lightweight state-of-the-art object detector. The early fusion based detector achieves solid detection recalls up to 99% for all cases of sensor failure and extreme weather conditions such as glary, dark, and foggy scenarios in fair real-time inference duration below 6 ms.
Journal Article
Study and valorisation of wastewaters generated in the production of bacterial nanocellulose
by
Dourado Fernando
,
Gama, Miguel
,
da Silva Francisco A G Soares
in
Anaerobic digestion
,
Anaerobic treatment
,
Biogas
2020
Two culture media were tested for the production of bacterial nanocellulose (BNC) under static culture fermentation, one containing molasses (Mol-HS), the other molasses and corn steep liquor (Mol-CSL), as a source of carbon and nitrogen, respectively. These are low-cost nutrients widely available, which provide very good BNC productivities. However, the use of these substrates generates wastewaters with high organic loads. Anaerobic digestion is one of the most promising treatments for industrial wastewaters with high organic loads since, beyond removal of the organic matter, it generates energy, in form of biogas. The wastewaters from BNC fermentation were thus evaluated for their biochemical methane potential through anaerobic digestion. For this, two wastewaters streams were collected: (i) the culture medium obtained after fermentation (WaF) and (ii) the WaF combined with BNC washing wastewaters (WaW). These two effluents—WaF and WaW—were characterized regarding their chemical oxygen demand, total nitrogen, total and volatile solids, to assess their suitability for anaerobic digestion. The biochemical methane potential of WaF and WaW from Mol-CSL wastewaters was (387 ± 14 L kg−1 VS) and (354 ± 4 L kg−1 VS), corresponding to a methanization percentage of (86.9 ± 3.1) % and (79.5 ± 0.9) %, respectively. After treatment, the chemical oxygen demand of WaF and WaW was reduced by (89.2 ± 0.4) and (88.7 ± 1.5), respectively. An exploratory test using an Upflow Anaerobic Sludge Blanket reactor for WaW treatment was also performed. The reactor was operated with a organic loading rate of [(6.5 ± 0.1) g L−1 d−1] and hydraulic retention time of 3.33 days, allowing a chemical oxygen demand removal of 58% of WaW. Results here obtained demonstrate, for the first time, the high potential of AD for the valorisation of the BNC fermentation wastewaters.
Journal Article
Pedestrian Behavior in Static and Dynamic Virtual Road Crossing Experiments
by
Pereira, Frederico
,
Faria, Susana
,
Freitas, Elisabete F.
in
Age groups
,
Auditory stimuli
,
crossing decision
2024
Virtual studies involving pedestrians have gained relevance due to the advantage of not exposing them to actual risk, and simulation setups have benefitted from rapid technical advancements, becoming increasingly complex and immersive. However, it remains unclear whether complex setups affecting participants’ freedom of movement impact their decision-making. This research evaluated the effects of a more realistic approach to studying pedestrian crossing behavior by comparing a perception-action task requiring participants to walk effectively along a semi-virtual crosswalk with a similar experiment using static crossing conditions. Using a CAVE system, two real-world streets were modeled in two different virtual scenarios, varying vehicle speed patterns and distance from the crosswalk. Visual stimuli were presented to two groups of 30 participants, with auditory stimuli adapted accordingly. The impact of various factors on participants’ crossing decisions was evaluated by examining the percentage of crossings, crossing start time, and time-to-passage. Overall, the experimental approach did not significantly affect participants’ crossing decisions.
Journal Article
The Influence of Noise Emitted by Vehicles on Pedestrian Crossing Decision-Making: A Study in a Virtual Environment
by
Pereira, Frederico
,
Silva, Emanuel
,
Soares, Francisco
in
Blindness
,
crossing decision-making
,
Decision making
2020
When crossing a road, pedestrians must detect traffic, combine data coming from different perceptual modalities, evaluate the time envelope for safely cross the street, and monitor the position of oncoming vehicles to perform corrective actions if needed. This study analyzed the influence of noise emitted by vehicles, or its absence, on pedestrians’ crossing decision-making. Experiments were performed in a virtual environment using two road scenarios. Participants were presented with stimuli of approaching vehicles that varied regarding speed, movement patterns, and auditory condition: one concerning the approaching of an electric vehicle, another regarding the approaching of a gasoline combustion vehicle, and, finally, a condition regarding the absence of auditory cues. Participants were tasked with indicating the moment when they decided to cross the street. The results show that, despite the noise variations caused by the type of vehicle and its speed pattern, the participants’ decision to cross was mostly based on vehicle distance. When a vehicle approaches the crosswalk from a short distance and with no occlusion to the pedestrian’s visibility, the sound does not seem to influence the pedestrians’ crossing decision-making.
Journal Article
Real-time full-field arbitrary optical waveform measurement
by
Scott, Ryan P.
,
Heritage, J. P.
,
Fontaine, Nicolas K.
in
639/624/1111/1112
,
639/624/1111/1116
,
639/624/400/584
2010
The development of a real-time optical waveform measurement technique with quantum-limited sensitivity, unlimited record lengths and an instantaneous bandwidth scalable to terahertz frequencies would be beneficial in the investigation of many ultrafast optical phenomena. Currently, full-field (amplitude and phase) optical measurements with a bandwidth greater than 100 GHz require repetitive signals to facilitate equivalent-time sampling methods or are single-shot in nature with limited time records. Here, we demonstrate a bandwidth- and time-record scalable measurement that performs parallel coherent detection on spectral slices of arbitrary optical waveforms in the 1.55 µm telecommunications band. External balanced photodetection and high-speed digitizers record the in-phase and quadrature-phase components of each demodulated spectral slice, and digital signal processing reconstructs the signal waveform. The approach is passive, extendable to other regions of the optical spectrum, and can be implemented as a single silicon photonic integrated circuit.
A measurement scheme that is capable of recording the amplitude and phase of arbitrary shaped optical waveforms with a bandwidth of up to 160 GHz is presented. The approach is compatible with integration on a silicon photonic chip and could aid the study of transient ultrafast phenomena.
Journal Article
Effectiveness of telesimulation on cardiorespiratory arrest for nursing students
by
Nunes de Miranda, Francisco Arnoldo
,
Morais Soares, Francisco Mayron
,
Nascimento da Silva, Maria Jocelane
in
educational technology
,
entrenamiento simulado
,
estudantes de enfermagem
2023
Objective. To evaluate the effectiveness of telesimulation on cardiorespiratory arrest to improve the performance of nursingstudents. Methods. This was an experimental study, whose sample consisted of 30 undergraduate nursing students from a Brazilian university. It was structured from two groups: an experimental (n=15) and a control (n=15). For both groups, expository classes and skills training were held. For the experimental group, a virtual clinical simulation scenario was implemented. Before the beginning of the interventions, a pre-test was applied and, after the end of this, a post-test was applied to evaluate the students ; gain of knowledge and skills. Results: From the analysis of the total correct answers and the scores obtained in the pre-test and post-test, it was found that there was an improvement in the performance of both study groups. Regarding the averages of the points obtained, there was a statistically significant difference between the groups (p=0.001). The post-test score was significantly higher than the pre-test score in the intervention group (p=0.001). Conclusion. The virtual scenario developed proved to be superior in improving the performance of nursing students in managing cardiorespiratory arrest when compared to traditional teaching methods.
Journal Article
Diversity and richness of the herbaceous plants on urbanized and non-urbanized dunes on the Brazilian Amazonian coast
by
Santos-Filho, Francisco Soares
,
Amorim, Ingrid Fabiana Fonseca
,
Lima, Patrícia Barbosa
in
Biodiversity
,
Composition
,
Conservation
2023
Urbanization directly affects the structure of vegetation, which makes essential studies focused on understanding and conserving the biodiversity along urban environments. This study aimed to describe the structure of the vegetation and identify the predominant herbaceous species in non-urbanized and urbanized sand dune areas, analyzing their diversity and richness in Maranhão Island. The study was conducted in six dunes area, in which were allocated where 150 plots were allocated in three urbanized area, and 150 plots in three non-urbanized area. We counted all the herbs in each plot (1 m2), recording data on richness, diversity and vegetation cover. To evaluate the difference in the composition of the areas, the following tests were used: Shapiro-Wilk W test (data distribution), Student t test (species richness) and Hutcheson t test (diversity comparison). We recorded 3,643 individuals: of this total, 2,075 individuals in urbanized dunes and 1,568 individuals in non-urbanized dunes; we found 91 species, 59 genera and 27 families. Richness was higher in urbanized areas; however, non-urbanized areas showed greater diversity and uniformity. The floristic composition of the areas differed, according to the species indicator, showing 19 typical urbanized dune species and 9 non-urbanized dune species. NMDS showed that the urbanized and non-urbanized dunes presented distinct species compositions and densities; the ANOSIM revealed a significant correlation between the type of dune and the degree of taxonomic similarity between plots. The diversity of the herbaceous vegetation provides important data that can be used to guide research on conservation and management of dune areas.
Journal Article
Clinical evaluation of allogeneic adipose tissue-derived stem cells for the treatment of osteoarthritis secondary to hip dysplasia in dogs
by
Martins, João Flávio Panattoni
,
Barros, Michele Andrade de
,
Leite, Caroline da Silva
in
Adipose tissue
,
AGRONOMY
,
Body fat
2024
This study assessed the efficacy of an intra-articular injection of allogeneic adipose tissue-derived from mesenchymal stem cells (AD-MSCs) for the treatment of hip dysplasia in dogs. The study group included 12 otherwise healthy dogs of different breeds, ages, weights, and degrees of hip dysplasia diagnosed using radiography. An orthopedic assessment was performed on all dogs before and at 30, 60, and 90 days after infusion of AD-MSCs(2 × 106cells). On the same days, each dog’s owner answered a questionnaire based on theHelsinkiChronic Pain Index. The data were converted to ordinal data based on the score for each variable, and the Friedman test for multiple comparisons was used to verify the results. Compared with the corresponding values on day 0, orthopedic and gait assessments and owners’ reported pain indexes improved over the 90-day observation period. These results suggested that treatment with allogeneic AD-MSCs significantly reduced the clinical signs associated with hip dysplasia during the study period. However, long-term studies are needed to determine the optimal therapeutic protocol for routine clinical use of AD-MSCs in hip dysplasia. RESUMO: O objetivo deste estudo foi avaliar a eficácia clínica da aplicação intra-articular de células-tronco mesenquimais alógenas derivadas do tecido adiposo (AD-CTM) no tratamento de cães portadores de osteoartrite secundária a displasia do coxofemoral (DCF). Doze cães de ambos os sexos, diferentes raças, idades e peso, portadores de graus variados de DCF comprovada em radiografia e livres de quaisquer outras alterações clínicas ou ortopédicas, foram utilizados no estudo. Todos os cães foram submetidos a avaliação ortopédica nos dias 0, 30, 60 e 90 após aplicação de AD-CTM na dose de 2 x 106. Além disso, os tutores preencheram a um questionário, baseado no Índice de dor crônica de Helsinque (IDCH) nos mesmos intervalos. Em comparação com o dia 0, observou-se melhora significativa na avalição em locomoção e físico-ortopédica assim como na avaliação dos tutores pelo IDCH ao longo dos 90 dias. Os resultados permitem inferir que as AD-CTM alógenas contribuíram significativamente para a redução dos sinais clínicos comumente associados a DCF durante o período de estudo. Entretanto, há necessidade de estudos de longo prazo para melhor determinação de protocolos terapêuticos baseados no uso de AD-CTM na rotina clínica.
Journal Article