1,284 research outputs found

    Olive Mill Wastewater Valorization through Steam Reforming Using Multifunctional Reactors: Challenges of the Process Intensification

    Get PDF
    Olive oil mill wastewater (OMW) is a polluting stream derived from the production of olive oil and is a source of environmental pollution; this is relevant in many countries around the world, but particularly in all the Mediterranean region where major producers are located. In this effluent, several pollutants are present-namely, sugars, fatty acids, and polyphenols, among others. Nowadays, to reduce the pollutant load, several treatment techniques are applied, but these technologies have numerous cost and efficiency problems. For this reason, the steam reforming of the OMW (OMWSR) presents as a good alternative, because this process decreases the pollutant load of the OMW and simultaneously valorizes the waste with the production of green H-2, which is consistent with the perspective of the circular economy. Currently, the OMWSR is an innovative treatment alternative in the scientific field and with high potential. In the last few years, some groups have studied the OMWSR and used innovative reactor configurations, aiming to improve the process' effectiveness. In this review, the OMW treatment/valorization processes, the last developments on catalysis for OMWSR (or steam reforming of similar species present in the effluent), as well as the last advances on OMWSR performed in multi-functional reactors are addressed

    Catalytic Steam Reforming of Biomass-Derived Oxygenates for H2 Production: A Review on Ni-Based Catalysts

    Get PDF
    The steam reforming of ethanol, methanol, and other oxygenates (e.g., bio-oil and olive mill wastewater) using Ni-based catalysts have been studied by the scientific community in the last few years. This process is already well studied over the last years, being the critical point, at this moment, the choice of a suitable catalyst. The utilization of these oxygenates for the production of green H2 is an interesting alternative to fuel fossils. For this application, Ni-based catalysts have been extensively studied since they are highly active and cheaper than noble metal-based materials. In this review, a comparison of several Ni-based catalysts reported in the literature for the different above-mentioned reactions is carried out. This study aims to understand if such catalysts demonstrate enough catalytic activity/stability for application in steam reforming of the oxygenated compounds and which preparation methods are most adequate to obtain these materials. In summary, it aims to provide insights into the performances reached and point out the best way to get better and improved catalysts for such applications (which depends on the feedstock used)

    Heart Rate Variability during Plateau Waves of Intracranial Pressure: a pilot descriptive study

    Get PDF
    This study aims to describe heart rate variability during the first episode of plateau waves of intracranial pressure (ICP) in Traumatic Brain Injury (TBI) in order to characterize and identify at bedside this cerebrovascular phenomenon. The general behavior of the heart rate variability (HRV) spectral measures expressed in the medians across patients is concordant with an increased HRV in the latter part of the baseline and plateau wave, followed by a decrease after the event and a new increase during the recovery. In low and high frequency bands the same increase is more marked in the parametric analysis. Interpretation of HRV may help clinicians to better identify the plateau waves and allow earlier management

    I-49. Influência do Ozono no processo de colonização bacteriana em Titânio

    Get PDF
    Objetivos: com uso de implantes dentários, surgem casos de ocorrência de peri-implantite, que se instala e permanece causando perda óssea peri-implantar podendo culminar no fracasso do implante dentário. Recentemente foram colocados no mercado equipamentos para aplicação de Ozono em medicina dentária, cuja aplicabilidade se baseia na potencial ação bacteriostático do Ozono mas da qual a evidência científica ainda é escassa. Deste modo, este estudo pretendeu avaliar a eficácia antimicrobiana do Ozono em culturas de Staphylococcus aureus sobre discos de titânio. Materiais e métodos: o efeito do ozono na formação de biofilme bacteriano pelo Staphylococcus aureus (Sa) foi testado através do uso de microplacas de 24 poços e de 8 discos de titânio com 1 cm2 de área e com uma superfície tratada quimicamente por aplicação de um ataque ácido (ácido fluorídrico ácido nítrico água na proporção 1:1:1). Cada disco foi revestido com um volume de inóculo correspondente a 1x108 ufc/ml e seco durante 30 min em condições assépticas. Cada disco inoculado foi tratado com jato de ozono durante 40 segundos, usando o HealOzone® (KaVo Dental GmbH, Biberach, Germany). Após esta aplicação do ozono os discos foram submersos em poços com 2 ml de 1% Tryptic Soy Broth (Difco®) e glucose a 1% (Sigma-Aldrich®). Simultaneamente, foi realizado um controlo positivo-disco e um controlo negativo. Após 48 h os discos foram recuperados e o número de unidades formadoras de colónias (UFC) foi determinado através do método Miles and Misra em Plate Count Agar (Merck®). As placas foram incubadas a 37 °C durante 24 h. Os resultados foram analisados aplicando a seguinte formula: %inibição = 100–(LOG UFCAMOSTRA COM OZONO/LOG UFCAMOSTRA SEM OZONO)x100. Resultados: verificou-se que houve uma inibição de crescimento do Sa de 31,4% após a aplicação do ozono. O tratamento da superfície do disco de titânio conduziu a uma redução de cerca de 2.5 ciclos logarítmicos. A analise estatística efetuada pelo método de Mann Whitney revelou a existência de uma diferença estatisticamente significativa entre os 2 grupos (com e sem aplicação de ozono) com o p = 0,0286. Conclusões: a aplicação do ozono em discos de titânio numa superfície revestida com elevado número de Sa (1x108 ufc/ml) conduziu a um efeito bacteriostático, demonstrando assim a potencial relevância deste equipamento na peri-implantite. São necessários mais estudos in vivo, com diferentes superfícies de implantes, para se testar a eficácia do Ozono no tratamento da patologia peri-implantar.info:eu-repo/semantics/publishedVersio

    An Enhanced Reservation-Based MAC Protocol for IEEE 802.15.4 Networks

    Get PDF
    The IEEE 802.15.4 Medium Access Control (MAC) protocol is an enabling standard for wireless sensor networks. In order to support applications requiring dedicated bandwidth or bounded delay, it provides a reservation-based scheme named Guaranteed Time Slot (GTS). However, the GTS scheme presents some drawbacks, such as inefficient bandwidth utilization and support to a maximum of only seven devices. This paper presents eLPRT (enhanced Low Power Real Time), a new reservation-based MAC protocol that introduces several performance enhancing features in comparison to the GTS scheme. This MAC protocol builds on top of LPRT (Low Power Real Time) and includes various mechanisms designed to increase data transmission reliability against channel errors, improve bandwidth utilization and increase the number of supported devices. A motion capture system based on inertial and magnetic sensors has been used to validate the protocol. The effectiveness of the performance enhancements introduced by each of the new features is demonstrated through the provision of both simulation and experimental results

    Social engineering program - MBA level: Designed for global education demand

    Get PDF
    Following the new trend in education, more focused on a global perspective, COPEC - Science and Education Research Council is offering an MBA, online, in Social Engineering for all Countries of CPLP - Portuguese Language Countries Community. The goal is to cover these countries' engineers, which are also seeking for opportunities, as the majority are countries of growing economy based on their very rich resources. The idea of an online program is the possibility of reaching a broader audience and at the same time of enriching the experience of offering and implementing a program that can disseminate ideas and concepts, which fits the needs of the target audience. The Education Research Team of COPEC is convinced that Engineers with proper knowledge and skills can take action in order to solve social problems, as engineers are problem solvers.This work was partly funded by FEDER funds through the Operational Competitiveness Program (COMPETE) and by FCT with the projects PEst-C/CTM/UI0264/2011 and FCOMP-01-0124-FEDER-022674

    Evidence of fractal structures in hadrons

    Full text link
    This study focuses on the presence of (multi)fractal structures in confined hadronic matter through the momentum distributions of mesons produced in proton-proton collisions between 23 GeV and 63 GeV. The analysis demonstrates that the qq-exponential behaviour of the particle momentum distributions is consistent with fractal characteristics, exhibiting fractal structures in confined hadronic matter with features similar to those observed in the deconfined quark-gluon plasma (QGP) regime. Furthermore, the systematic analysis of meson production in hadronic collisions at energies below 1 TeV suggests that specific fractal parameters are universal, independently of confinement or deconfinement, while others may be influenced by the quark content of the produced meson. These results pave the way for further research exploring the implications of fractal structures on various physical distributions and offer insights into the nature of the phase transition between confined and deconfined regimes.Comment: 23 pages, 11 figures, supplementary materia

    DyNetVis: a system for visualization of dynamic networks

    Get PDF
    The concept of networks has been important in the study of complex systems. In networks, links connect pairs of nodes forming complex structures. Studies have shown that networks not only contain structure but may also evolve in time. The addition of the temporal dimension adds complexity on the analysis and requests the development of innovative methods for the visualization of real-life networks. In this paper we introduce the Dynamic Network Visualization System (DyNetVis), a software tool for visualization of dynamic networks. The system provides several tools for user interaction and offers two coordinated visual layouts, named structural and temporal. Structural refers to standard network drawing techniques, in which a single snapshot of nodes and links are placed in a plane, whereas the temporal layout allows for simultaneously visualization of several temporal snapshots of the dynamic network. In addition, we also investigate two approaches for temporal layout visualization: (i) Recurrent Neighbors, a node ordering strategy that highlights frequent connections in time, and (ii) Temporal Activity Map (TAM), a layout technique with focus on nodes activity. We illustrate the applicability of the layouts and interaction functionalities provided by the system in two visual analysis case studies, demonstrating their advantages to improve the overall user experience on visualization and exploratory data analysis on dynamic networks

    High-resolution seismocardiogram acquisition and analysis system

    Get PDF
    Several devices and measurement approaches have recently been developed to perform ballistocardiogram (BCG) and seismocardiogram (SCG) measurements. The development of a wireless acquisition system (hardware and software), incorporating a novel high-resolution micro-electro-mechanical system (MEMS) accelerometer for SCG and BCG signals acquisition and data treatment is presented in this paper. A small accelerometer, with a sensitivity of up to 0.164 µs/µg and a noise density below 6.5 µg/ Hz is presented and used in a wireless acquisition system for BCG and SCG measurement applications. The wireless acquisition system also incorporates electrocardiogram (ECG) signals acquisition, and the developed software enables the real-time acquisition and visualization of SCG and ECG signals (sensor positioned on chest). It then calculates metrics related to cardiac performance as well as the correlation of data from previously performed sessions with echocardiogram (ECHO) parameters. A preliminarily clinical study of over 22 subjects (including healthy subjects and cardiovascular patients) was performed to test the capability of the developed system. Data correlation between this measurement system and echocardiogram exams is also performed. The high resolution of the MEMS accelerometer used provides a better signal for SCG wave recognition, enabling a more consistent study of the diagnostic capability of this technique in clinical analysis.This work is supported by FCT with the reference project UID/EEA/04436/2013, COMPETE 2020 with the code POCI-01-0145-FEDER-006941

    From handcrafting to a certified and ergonomic collaborative workstation: the digital transformation process

    Get PDF
    As manufacturing enters an era of mass customization, new technological solutions with more versatility and flexibility are brought to the industry. Collaborative robots, or COBOTs, can now safely work near humans, a key advantage that enables highly-flexible production and opens the possibility to tackle the incidence of occupational health problems. Although the advantages of collaborative robotic manufacturing have been extensively praised, adapting a manual production workstation to integrate robotic technology is far from being a linear and easy process. In this work, we explore this delicate balance between the ergonomic, production, and safety requirements in the design of a new collaborative cell. We explain the different steps of this digital transformation process and the thought process behind human-robot task allocation to maximize the collaborative robot efficiency while improving the work conditions. This work describes the development of a certified and production-ready collaborative workstation based on ergonomic criteria. Results show a significant reduction in the global ergonomic risk score associated with the workers' actions and postures and an increase in production quotas, compared to the previous manual process.This work was supported by NORTE-06-3559-FSE-000018, integrated into the invitation NORTE-59-2018-41, aiming to hire highly-qualified human resources, co-financed by the Regional Operational Programme of the North 2020, thematic area of Competitiveness and Employment, through the European Social Fund (ESF)
    • …
    corecore