Proton conductivity of Nafion-azolebisphosphonates membranes for PEM fuel cells

Energy systems with cleaner and sustainable sources are crucial challenges of the 21st century to deal with the environmental threat of global warming and the declining reserves of fossil fuels. Fuel cells are electrochemical devices that convert the chemical energy stored in a fuel directly into electrical energy, providing electrical energy with high efficiency and low environmental impact. Among them, proton exchange membrane fuel cells (PEMFCs) are considered promising power sources, due to their high power density and high power-to-weight ratio but their performance depends crucially on their proton exchange membranes [1]. Usually, these membranes are made of organic polymers containing acidic functionalities (ex. Nafion® ), which proton transport properties strongly depend on their water content and, consequently, limit their operation temperatures up to 90ºC. Preliminary studies have demonstrated that incorporation of aryl-bisphosphonic acids into Nafion, by casting, results in an enhancement of the proton conductivity of the membrane. The aim of this work was the preparation of new Nafion membranes doped with azolebisphosphonates derivatives, which could act as a source of protons and also function as proton acceptors, facilitating the intermolecular transmission of protons through the membrane

A CFD study of a pMDI plume spray

Uncorrected proofAsthma is an inflammatory chronic disease characterized by airway obstructions disorders. The treatment is usually done by inhalation therapy, in which pressurized metered-dose inhalers (pMDIs) are preferred devices. The objective of this paper is to characterize and simulate a pMDI spray plume by introducing realistic factors through a computational fluid dynamics (CFD) study. Numerical simulations were performed with Fluent® software, by using a three-dimensional “testbox” for room environment representation. A salbutamol/HFA-134a formulation was used for characterization, whose properties taken as input for the CFD simulations. Spray droplets were considered to be composed by ethanol, salbutamol and HFA-134a. Propellant evaporation was taken into consideration, as well as, drag coefficient correction. Results showed an air temperature drop of 3.3 °C near the nozzle. Also, an increase in air velocity of 3.27 m/s was noticed. The CFD results seem to be in good agreement with Dunbar (1997) data on particle average velocity along the axial distance from the nozzle.National Funds-Portuguese Foundation for Science and Technology, under Strategic Project PEst-C/EME/UI4077/2011 and PEst-OE/EME/299UI0252/201

Exergy efficiency optimization for gas turbine based cogeneration systems

Energy degradation can be calculated by the quantification of entropy and loss of work and is a common approach in power plant performance analysis. Information about the location, amount and sourc es of system deficiencies are determined by the exergy analysis, which quantifies the exergy destruction. Micro - gas turbines are prime movers that are ideally suited for cogeneration applications due to their flexibility in providing stable and reliable power. This paper presents an exergy analysis by means of a numerical simulation of a regenerative micro - gas turbine for cogeneration applications . The main objective is to study the best configuration of each system component , considering the minimization of the system irreversibilities . Each component of the system was evaluated considering the quantitative exergy balance . Subsequently the optimization procedure was applied to the mathematical model that describes the full system. The rate of irreversibility, efficiency and flaws are highlighted for each system component and for the whole system. The effect of turbine inlet temperature change on plant exergy destruction was also evaluated . The results disclose that considerable exergy destruction occurs in the combustion chamber. Also, it was revealed that the exergy efficiency is expressively dependent on the changes of the turbine inlet temperature and increases with the latter .The authors would like to express their acknowledgments for the support given by the Portuguese F01mdation for Science and Technology (FCT) through the PhD grant SFRH/BD/62287/2009. This work was financed by National Funds-Portuguese Foundation for Science and Technology, under Strategic Project and PEst-OE/EME/UI0252/2011 and also the PEst-C/EME/UI4077/2011

Biopolymeric matrices for structural and functional stabilization of bacteriophages

In the recent past years, bacteriophage research has experienced a renaissance due to their potential application in the pharmaceutical field, especially with the increase of bacterial resistance to antibiotics and the possibility to take part in new methods of early detection and diagnosis of bacterial infections. In that context, the structural and functional stabilization of bacteriophages using biopolymeric microporous hydrogels represents a promising research focus with a broad potential biomedical/ biopharmaceutical application. The scope of this work was to develop biopolymeric non-toxic phage-hydrogels of agar and sodium alginate, obtained at neutral pH and mild polymerization conditions, in order to offer adequate characteristics to the maintenance of phage’s lytic activity. Disc-like phage-hydrogels were prepared, with a phage and polymer concentration of 1.3x108 PFU/ml and 1.5% (w/v), respectively. Regarding the alginate hydrogels, CaCO3 (22.5 mM) and GDL (48 mM) were also included in the formulation. Agar hydrogels were prepared naturally by jellification, as a function of temperature lowering, and alginate hydrogels were prepared by internal gelation. The matrices were inoculated with a suspension of susceptible (host) bacteria and incubated at 37 ºC for 24h. Observation of bacterial lawn’s lysis demonstrated that bacteriophages kept their lytic activity, being the method of physical entrapment able to promote their stabilization. Cryo-SEM analysis revealed that both types of phage-hydrogels present interconnective microporous network, which guaranties a facilitated access of the phages to the bacteria, ensuring an efficient lysis of the host bacteria present in the surface of the hydrogels.The developed hydrogels also present appropriate physical and chemical properties for a wider variety of applications in the field of pharmaceutical sciences, such as controlled release of (macro)molecules, cell immobilization and 3D support for tissue regeneration

Numerical study of the unsteady flow in simplified and realistic iliac bifurcation models

Cardiovascular diseases are a major cause of death and disability worldwide and they are commonly associated with the occurrence of atherosclerotic plaque deposition in the vessel walls, a process denoted as atherosclerosis. This is a chronic and progressive inflammatory disease of large-/medium-sized blood vessels that affects blood flow profiles, with the abdominal aorta and its branches being one of the locations prone to the development of this pathology, due to their curvatures and bifurcations. In this regard, the effect of flow patterns was studied and compared for both a simplified three-dimensional model of aorta bifurcation on the iliac arteries and a realistic model of iliac bifurcation, which was constructed from a computational tomography medical image. The flow patterns were analyzed in terms of velocity and wall shear stress distribution, but a special focus was given to the size and location of the recirculation zone. The simulations were performed using the Computational Fluid Dynamics software, FLUENT, taking into account the cardiac cycle profile at the infrarenal aorta. The shear stress and the velocity distribution observed for both models indicated that higher shear stress occurred along the flow divider wall (inner wall) and low shear stress occurred along the outer walls. In addition, the results demonstrated that the wall shear stress profiles were deeply affected by the transient profile of the cardiac cycle, with the deceleration phase being the most critical phase to the occurrence of backflow.This work was supported by FCT—Fundação para a Ciência e Tecnologia through the R&D Units Project Scope: UIDB/00319/2020, UIDB/04077/2020, and NORTE-01-0145-FEDER-030171, funded by COMPETE2020, NORTE 2020, PORTUGAL 2020, and FEDER

Development of tools to support the production planning in a textile company

Technologies are constantly evolving and so with advances in industry 4.0, its intelligent technologies with production planning and control (PPC) give rise to a smart PPC. Nowadays, one of the fundamental systems in a company is the ERP, since it allows the integration of various information from the different areas belonging to an organization, which allows access to data in real time, among other things. Through a work carried out in a textile company, it was noticeable the need to develop a tool to support its installed ERP system and the respective data control. Thus, it is noted that PPC systems, which include the integration of all areas of a company, must be adapted to its environment, work method and characteristics. With the application of this tool, it was possible to perceive an increase in efficiency and speed in obtaining the desired results, being that it is still under development and could evolve even more.FCT - Fundação para a Ciência e a Tecnologia(UIDB/00319/2020

Internal variation temperature analysis and thermal mapping of a central processing unit (CPU)

This work aims to analyze the internal temperature variation of the central processing unit (CPU) of a personal computer, through the development of three distinct scenarios: one for reference and two aiming at its performance improvement. The finite volume method (FVM) was applied. Thus, Hypermesh 13.0 software was used for geometric model development and for surface mesh generation. For model contour conditions configuration, virtual simulation and post-processing, Starccm+ software was used. The results of this work indicated hot spots due to the heat dissipated during the operation of the CPU components. As expected, the processor region presented the highest temperatures in all proposed scenarios. The opening on the side of the cabinet, proposed in scenario 2, allowed a temperature reduction of about 18 °C in the processor region. In turn, scenario 3, in which heat exchangers were used in order to minimize the temperature of the hot air from the recirculation in the processor region, showed a minimum temperature reduction (about 3 °C) when compared to scenario 1

Concurrent and construct validation of a new scale for rating perceived exertion during elastic resistance training in the elderly

Purpose: To examine the concurrent and construct validity of a new perceptual scale to control the exercise intensity using elastic bands (Resistance Intensity Scale for Exercise; RISE) in the elderly. Methods: Twenty-six participants underwent two sessions consisting of 4 exercises. The participants performed three sets of 15 repetitions per exercise of either low, medium, or high intensity. The criterion variables were heart rate and applied force (mean and peak). Following the final repetition of each set, active muscle (AM) and overall body (OB) ratings of perceived exertion (RPE) were collected from RISE and the OMNI-Resistance Exercise Scale of perceived exertion with elastic bands (OMNI-RES EB). Construct validity was established by correlating the perceptual score obtained from both scales, RISE and OMNI-RES EB. Results: Significant (p ≤ 0.05) and positive linear relationships between both scales were found (RPE-AM R2 = 0.90; RPE-OB R2 = 0.77). Significant differences in heart rate applied force, and RISE scores were observed between the sets of the three intensities. For all 4 analyzed exercises, high-intensity sets elicited higher heart rate, applied force, and perceptual scores compared with the medium- and low-intensity sets. Furthermore, the medium-intensity sets produced higher perceptual, physiologic, and performance responses than the low-intensity sets. Intersession reliability was 0.88 for heart rate, 0.94 and 0.95 for applied force, 0.88 for the RPE-AM, and 0.80 for the RPEOB. Conclusion: The RISE scale can be considered a valid method for assessing the perceived exertion during resistance exercises performed with bands in the elderly

Biological treatment of solid wastes from the tobacco industry for enzyme production

Aiming at the production of enzymes using solid wastes from the tobacco industry, the solid fermentation kinetics of Aspergillus niger and Aspergillus terreus using waste of dark tobacco and Virginia tobacco as substrate were characterized. The efficiency of the fermentation process was evaluated by determining the enzymatic activity of the three enzymes that constitute the cellulose enzymatic system (CMCase, PFase and Xylanase). The results obtained led to the establishment of the best initial conditions of fermentation and the selection of the most efficient microorganism for enzyme production. The best results were obtained with Aspergillus terreus for both tobacco residues. In the case of black tobacco, the best incubation temperature was 31 ºC for the enzymes CMCase and Xylanase and 36 ºC for the PFase and initial pH 5.5 for the three enzymes. For the Virginia tobacco, the best incubation temperature and initial pH are the same for the three enzymes, 36 ºC and 5.5 respectively. The biological activity of the fermented tobacco residues was evaluated being the highest rate of inhibition of microbial growth – 72% - obtained with the residue of Virginia tobacco treated with Aspergillus niger

Budd-chiari syndrome and unsuspected gastric adenocarcinoma

A síndrome de Budd-Chiari não tem sido descrita em pacientes jovens portadores de câncer gástrico. Relata-se caso de síndrome de Budd-Chiari e linfangite carcinomatosa em homem branco de 28 anos, portador de câncer gástrico insuspeito, apresentando icterícia, hematêmese e dispnéia. O estudo de autopsia revelou adenocarcinoma gástrico infiltrando vasos das camadas submucosa e serosa, com sangramento do estômago e intestino, além de metástases hepáticas e pulmonares. Múltiplos microtrombos mistos (fibrina, plaquetas e células tumorais) foram observados em pequenos vasos sangüíneos pulmonares e tanto os vasos linfáticos subpleurais quanto o interstício pulmonar continham células tumorais metastáticas.The Budd-Chiari syndrome has not been described in young patients with gastric cancer. A case of Budd-Chiari syndrome and carcinomatous lymphangitis is reported in a 28 years-old white man with unsuspected gastric cancer, presenting jaundice, hematemesis and dyspnea. Autopsy disclosed gastric adenocarcinoma invading vessels of the submucous and serous layers, with gastric and intestinal bleeding, liver and lung metastases. Multiple mixed (fibrin, platelets and tumor cells) microthrombi were observed in small pulmonary blood vessels, and both subpleural lymph vessels and lung interstitium contained metastatic tumor cells