51 research outputs found
Scaling-up of wastewater bioremediation by Tetradesmus obliquus, sequential bio-treatments of nutrients and metals
No full textMicroalgae may be exploited in water or wastewater treatment facilities to reduce excess concentrations of nutrients and metals to comply with regulatory limits. In this study, we characterized the growth and phosphorus (P) removal capacity of an isolated strain of Tetradesmus obliquus VRUC280. Investigations were carried out from laboratory scale (50 mL) up to a 100 L outdoor photobioreactor (PBR). After 10 days, batch cultures removed up to 74% of the media P, while in the PBR, 95% removal was achieved within five days. The harvested biomass was then inactivated (freeze-dried) and used for metal adsorption tests, employing solutions containing 6.0 mg Cu L −1 or 4.8 mg Ni L −1 . Metal removal rates were evaluated after 15, 30, 60 and 120 min by the analysis of liquid and biomass metal contents. For the latter, a specific biomass digestion method was developed. Cu removal ranged between 50% and 65%, while for Ni, removal varied between 30% and 50%. 300–400 mg Cu Kg DW −1 and 130–250 mg Ni Kg DW −1 were rapidly adsorbed on the cell surface of T. obliquus (ca. 15–30 min incubations). This study demonstrates the potential of microalgae, in this case T. obliquus, to remove sequentially P and metals from aqueous media
Sol–gel synthesis and characterization of Co-doped LSGM perovskites
No full textOne of the major requirements for the development and commercialization of low-cost SOFCs is the reduction in the operating temperature. One of the methods to reach this aim is the use of solid electrolytes which exhibit superior ionic conductivity at intermediate temperatures (IT, T < 800 °C). Among these ionic conductors, doped LaGaO3 materials show high oxide ionic conductivity in the 600–800 °C range. These perovskites are usually prepared by time- and energy-consuming solid state reaction. In this paper, La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) and La0.8Sr0.20Ga0.8Mg0.2−xCoxO3−δ (LSGMC) powders containing different amounts of Co (x = 0.05, 0.085 and 0.10) were prepared from precursors synthesised by citrate sol–gel method. The precursors were calcined at 1000 °C (10 h) and dense high-purity pellets were obtained by pressing (300 MPa) and sintering in air at 1475 °C (5, 10 and 20 h). Sintered pellets of LSGM and LSGMC contained very small amounts (<1%) of SrLaGa3O7 and SrLaGaO4, respectively, as detected by X-ray diffraction (XRD) and by the combined use of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The data clearly showed the feasibility of sol–gel methods to produce Co-doped LSGM perovskite type oxides
Ripensare la borgata romana: il caso del Quarticciolo
No full textAmong the examples of the Roman suburbs best known as “borgate”, built between 1924 and 1937, the case study of Quarticciolo stands out clearly for the hierarchical design of the plan and for the architectural quality of the whole intervention.
In spite of the hostile attitude of critics, some of these projects still maintain distinctive features considered by the population as identity-creating representations.
Quarticciolo was designed between 1939-1940 and it was the last realization of the construction program in Roman suburbs promoted by the Italian government.
The Ifacp office was coordinated by Roberto Nicolini, author of the workers' village in Torre Gaia and of the suburb of Trullo, the latter designed with Giuseppe Nicolosi.
The first phase of construction was completed between 1941-1943 but the construction site went on during the second world war.
On July 1943 it was interrupted by the bombing of Rome when many unfinished houses were occupied by homeless and displaced persons coming from other suburbs in the east part of the eternal city.
The studying case analyzed in this paper is an urban settlement completely integrated with the topography of the area. Thanks to the hierarchy of its parts Quarticciolo is able to “resist” to all the changes of the Roman outskirt.
The urban model proposed in the Quarticciolo can stimulate a positive reflection: in fact, this intervention of council housing is able to produce the idea of “organism”, different from any utopia of several towns built during the fascist regime or from any “self-referential” context, like the districts built after the world war
Role of Endothelium in Cardiovascular Sequelae of Long COVID
No full textThe global action against coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2 infection, shed light on endothelial dysfunction. Although SARS-CoV-2 primarily affects the pulmonary system, multiple studies have documented pan-vascular involvement in COVID-19. The virus is able to penetrate the endothelial barrier, damaging it directly or indirectly and causing endotheliitis and multi-organ injury. Several mechanisms cooperate to development of endothelial dysfunction, including endothelial cell injury and pyroptosis, hyperinflammation and cytokine storm syndrome, oxidative stress and reduced nitric oxide bioavailability, glycocalyx disruption, hypercoagulability, and thrombosis. After acute-phase infection, some patients reported signs and symptoms of a systemic disorder known as long COVID, in which a broad range of cardiovascular (CV) disorders emerged. To date, the exact pathophysiology of long COVID remains unclear: in addition to the persistence of acute-phase infection mechanisms, specific pathways of CV damage have been postulated, such as persistent viral reservoirs in the heart or an autoimmune response to cardiac antigens through molecular mimicry. The aim of this review is to provide an overview of the main molecular patterns of enduring endothelial activation following SARS-CoV-2 infection and to offer the latest summary of CV complications in long COVID
Infrared temperature measurements on fast moving targets: A novel calibration approach
No full textIn this study, an infrared system is developed for accurate measurements of surface temperature and heat transfer on fast moving targets. The system was designed for the Oxford Turbine Research Facility, a world-leading experimental facility delivering highly engine representative, scalable heat transfer results for aerospace research. Infrared thermography is employed to acquire temperature maps of high-pressure turbine blades, allowing assessment of surface thermal conditions including heat transfer coefficient, adiabatic wall temperature, Nusselt number, cooling effectiveness, and metal effectiveness. Achieving accurate infrared thermography measurements in rotating turbomachinery experimental conditions is arduous due to reflections from the surroundings, low emissivity of metallic parts, and motion blur resulting from high speed. To overcome these challenges, calibration procedures were developed against a traceable standard using a bespoke steady experimental facility. A method to determine the reflected temperature from surroundings was also validated. Correction for all measurement disturbances is demonstrated to within the accuracy of the primary measurement thermocouple. Finally, the developed calibration method was validated on a fast-moving rotating geometry demonstrating accurate correction for all measurement disturbances, without the need for an in situ calibration. A detailed uncertainty analysis for each calibration step is also presented.Fluid Mechanic
Project ElectriFly: Electric Commuter Aircraft with Mid-Flight Recharging Capability
No full textBachelor Thesis: Design Synthesis Exercise 2023Group 13: Electric General Aircraftin collaboration withGroup 10: Mid-Flight Recharging SystemAddressing the pressing need for sustainability amid climate change, the aviation sector is under pressure to mitigate its significant carbon emissions. As aviation accounts for over 2% of global emissions, achieving zero-emissions aviation by 2050 is crucial. The challenge lies in finding alternatives to jet fuel. One option is battery-powered electric aviation, but limitations such as range constraints and emissions during production and disposal must be considered.This report proposes a solution to extend the range of all-electric passenger aircraft. The ElectriFly aircraft can currently fly 600km at 110m/s before requiring recharging. To achieve perpetual flight capability, a mid-flight recharging system is introduced using a drogue and probe system, similar to military refueling technologies. This approach not only increases range but also reduces turn around time at airports.Powered by four parallel-connected solid-state batteries with an energy density of 600kWh/kg, the ElectriFly aircraft features 14 propellers using distributed propulsion and potential plasma actuators. This setup improves aerodynamic performance, reduces noise, and allows for regenerative braking, easing the burden on the recharging drone. Real-time data sensors enable predictive maintenance, minimizing downtime and providing pilots with crucial flight anomaly information.This research presents a promising solution for electric aircraft limitations through mid-flight recharging. The proposed ElectriFly aircraft offers extended range capabilities and improved operational efficiency, supporting the goal of sustainable aviation.AE3200 - Design Synthesis ExerciseAerospace Engineerin
Electrochemical behaviour of Co-doped LSGM perovskites prepared by sol-gel synthesis
No full textABSTRACTLa0.8Sr0.2Ga0.8Mg0.2-xCoxO3-δ (LSGMC) powders containing different amounts of Co (x = 0.05 and 0.085) were prepared by a citrate sol-gel method. Crystalline powders were obtained by firing at 1000°C (10 h) and dense high-purity pellets were prepared by pressing (300 MPa) and sintering in air at 1475°C (5, 10 and 20 h). The sintered pellets of LSGMC were characterized by X-Ray Diffraction (XRD) Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The conductivity of sintered LSGMC pellets containing different amounts of Co ions in the B sites of the perovskite lattice was assessed by electrochemical impedance spectroscopy (EIS) in the 250–750 °C temperature range. Conductivity values and apparent activation energies were in good agreement with previously published data referring to materials with same composition, but prepared by solid-state reaction.</jats:p
SEM-EDX Analysis of Gunshot Residue on Pig Cranial Bone Following Decomposition and Maceration
No full textabstract: Distinguishing between projectile and blunt force or sharp force trauma can be complicated by processes that result in fragmentation or loss of skeletal features. Postmortem processes that obscure skeletal features may result in the inability to properly determine the mechanism of trauma using morphology alone. The presence of gunshot residue (GSR) is indicative of a gunshot event and can be used to differentiate between etiologies of skeletal trauma. Primer GSR is composed of barium (Ba), antimony (Sb), and lead (Pb), which are vaporized during the firearm discharge and can be deposited in small quantities on surfaces within proximity of a gunshot event. Scanning Electron Microscopes with Energy Dispersive X-Ray Spectroscopy (SEM-EDX) have been used in the past to detect GSR on a variety of surfaces including bone. The purpose of this study is to determine the ability to detect GSR on bone tissue using SEM-EDX following warm-water maceration or decomposition
Numerical investigation of bubble dynamics and flow boiling heat transfer in cylindrical micro-pin-fin heat exchangers
No full textMicro-pin-fin evaporators are a promising alternative to multi-microchannel heat sinks for two-phase cooling of high power-density devices. Within pin-fin evaporators, the refrigerant flows through arrays of obstacles in cross-flow and is not restricted by the walls of a channel. The dynamics of bubbles generated upon flow boiling and the associated heat transfer mechanisms are expected to be substantially different from those pertinent to microchannels; however, the fundamental aspects of two-phase flows evolving through micro-pin-fin arrays are still little understood. This article presents a systematic analysis of flow boiling within a micro-pin-fin evaporator, encompassing bubble, thin-film dynamics and heat transfer. The flow is studied by means of numerical simulations, performed using a customised boiling solver in OpenFOAM v2106, which adopts the built-in geometric Volume of Fluid method to capture the liquid–vapour interface dynamics. The numerical model of the evaporator includes in-line arrays of pin-fins of diameter of 50μm and height of 100μm, streamwise pitch of 91.7μm and cross-stream pitch of 150μm. The fluid utilised is refrigerant R236fa at a saturation temperature of 30 °C. The range of operating conditions simulated includes values of mass flux G=500–2000kg/(m2s), heat flux q=200kW/m2, and inlet subcooling ΔTsub=0–5K. This study shows that bubbles nucleated in a pin-fin evaporator tend to travel along the channels formed in between the pin-fin lines. Bubbles grow due to liquid evaporation and elongate in the direction of the flow, leaving thin liquid films that partially cover the pin-fins surface. The main contributions to heat transfer arise from the evaporation of this thin liquid film and from a cross-stream convective motion induced by the bubbles in the gap between the cylinders, which displace the hot fluid otherwise stagnant in the cylinders wakes. When the mass flow rate is increased, bubbles depart earlier from the nucleation sites and grow more slowly, which results in a reduction of the two-phase heat transfer. Higher inlet subcooling yields lower two-phase heat transfer coefficients because condensation becomes important when bubbles depart from the hot pin-fin surfaces and reach highly subcooled regions, thus reducing the two-phase heat transfer
Analysis of Sexual Dimorphism in Sub-adult Crania
No full textabstract: Forensic anthropologists rely on the validated sex determination methods that utilize post-cranial elements in adult remains, but, recently, research has been conducted to determine adult remain sex using just the skull. Similar research for sub-adult remains is lacking the robustness and validation that adult determination methods possess. This study utilized 20 crania measurements taken from CT scans of child patients with known sexes at the Phoenix Children’s Hospital to investigate if a sex determination method could be produced. The measurements were assessed with a t-Test, Linear Discriminant Analysis, and Principle Component Analysis to determine if sexual dimorphism was detectable and if the predictive model had discriminant power when the sample size was categorized by age. The results revealed that a few measurements were dimorphic, but were not statistically significant to determine the sex of a sub-adult outside of the sample population. Future investigations will remove age group classification to observe if this model can predict age
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