120 research outputs found
Designing aircraft in Italy; internship at Piaggio Aero Industries
No full textFrom October 2012 to January 2013, I went to the south of Italy to do my internship at Piaggio, the company famous for manufacturing the P.180 Avanti business aircraft. The office where I was located was in Pozzuoli, a town just outside the city of Naples, in the shadow of Mount Vesuvius.Aerospace Engineerin
Follow-the-Leader Guidance, Navigation, and Control of Surface Vessels: Design and Experiments
No full textA novel follow-the-leader approach for azimuth-driven vessels is devised and experimentally tested in a model-scale outdoor scenario. The vessels are equipped with global navigation satellite and inertial navigation systems. A line-of-sight algorithm ensures the yaw-check ability of the follower vessel along the leader's path, while a speed-regulation allows to track its velocity. Track generation, guidance, navigation, and control modules are designed and assembled to be executed on-board in real time. The results of an outdoor experimental campaign are illustrated to show the effectiveness of the proposed approach.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
The role of ethics in science: a systematic literature review from the first wave of COVID-19
No full textThis paper proposes a systematic literature review on ethics and CoviD-19, aiming to understand the impact and the perception of the pandemic during the first wave (January-June 2020) and the consequences one year later. PubMed was systematically searched up May 2020 to identify studies that took into consideration various ethical issues that have been arising from the Covid-19 outbreak. The eligibility of the papers was determined by two authors, who screened the results mediated by a third author. In order to facilitate the screening, the titles were divided into five sub-thematic macro-areas, namely allocation, policy, specialist, clinical trials, and technology and, when possible, per geographical area. Specifically, a posteriori, we decided to focus on the papers referring to policies and technology, as they highlighted ethical issues that are not overused and worthy of particular attention. Thus, 38 studies out of 233 met our inclusion criteria and were fully analysed. Accordingly, this review touches on themes such as fairness, equity, transparency of information, the duty of care, racial disparities, the marginalisation of the poor, and privacy and ethical concerns. Overall, it was found that despite the increased awareness of interdisciplinarity and the essential reference to ethics, many scientific articles use it with little competence, considering it only a "humanitarian" enrichment. In fact, as we understand, reflecting a year after the outbreak of the pandemic, although Covid-19 is leading scientists to increasingly recognise the importance of ethical issues, there is still a lot of confusion that could be helped by establishing international guidelines to act as a moral compass in times of crisis.Supplementary informationThe online version contains supplementary material available at 10.1007/s12553-021-00570-6
There is life beyond the statistical significance
No full textThis article challenges the “tyranny of P-value” and promote more valuable and applicable interpretations of the results of research on health care delivery. We provide here solid arguments to retire statistical significance as the unique way to interpret results, after presenting the current state of the debate inside the scientific community. Instead, we promote reporting the much more informative confidence intervals and eventually adding exact P-values. We also provide some clues to integrate statistical and clinical significance by referring to minimal important differences and integrating the effect size of an intervention and the certainty of evidence ideally using the GRADE approach. We have argued against interpreting or reporting results as statistically significant or statistically non-significant. We recommend showing important clinical benefits with their confidence intervals in cases of point estimates compatible with results benefits and even important harms. It seems fair to report the point estimate and the more likely values along with a very clear statement of the implications of extremes of the intervals. We recommend drawing conclusions, considering the multiple factors besides P-values such as certainty of the evidence for each outcome, net benefit, economic considerations and values and preferences. We use several examples and figures to illustrate different scenarios and further suggest a wording to standardize the reporting. Several statistical measures have a role in the scientific communication of studies, but it is time to understand that there is life beyond the statistical significance. There is a great opportunity for improvement towards a more complete interpretation and to a more standardized reporting.Fil: Ciapponi, Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Belizan, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Piaggio, Gilda. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Yaya, Sanni. Imperial College London; Reino Unido. University of Ottawa; Canad
Follow-the-Leader Control Strategy for Azimuth Propulsion System on Surface Vessels
No full textThis paper presents an effective autonomous follow-the-leader strategy for Azimuthal Stern Drive vessels. The control logic has been investigated from a theoretical point of view. A line-of-sight algorithm is exploited to ensure yaw-check ability, while a speed-check feature is implemented to track the velocity of the target along the path. For this purpose, a linearised manoeuvrability model for azimuthal drive surface vessels is presented. A model-based control synthesis is proposed to ensure the stability of the closed-loop system and robust PID controllers are designed by using Linear Matrix Inequalities technique. The control strategy has been successively validated in two steps, initially by using simulation techniques, and then experimentally using an outdoor scenario with model scale tugs. The path planning, navigation, guidance and control modules are studied, detailed, and digitally implemented on-board of the model scale tugs. The models are supplied with GNSS+INS navigation system. Low-level management and control of Azimuthals angles and shaft revolutions is implemented on-board. High-level decen-tralised path planning, guidance, and control sequence evaluation are dealt with at a remote ground station. In particular, the presented follow-the-leader strategy meets the most generic needs of platooning convoys, and, in the specific instance, of Escort convoy tugs. The operative profile of the latter concerns long-lasting and routine chases with the continuous demand of tuning heading and speed to track the target vessels, until the rare occurrence of an emergency event. In a realistic scenario, the proposed control system would be beneficial for the tug master’s lucidity and alertness, while reducing avoidable risks. At the end of the paper, the results of the experimental campaign are shown to demonstrate the effectiveness of the proposed control logic.Transport Engineering and Logistic
The Potential of Anaerobic Digestion combined with Dissolved Air Flotation (AD-DAF) for Wastewater Treatment
No full textIn the context of a worldwide scenario characterized by a progressively expanding human population, the combining effects of climate change, escalating water stress, and the degradation of freshwater resources, water reclamation has emerged as a viable solution to alleviate the critical issue of water scarcity. Several streams around the world are subjected to a wide range of pollutants concentration and water-born pathogens, like antibiotic-resistant bacteria (ARB), due to human activity. The latter can be considered as a global emerging threat, due to its potential to deteriorate the human health system. Thus, adequate treatment of these polluted streams is needed to overcome water scarcity. While anaerobic membrane bioreactors (AnMBR) systems are a promising anaerobic digestion (AD) technology to treat municipal and concentrated wastewater, the application of membranes to separate solids from the bioreactor broth also has considerable constraints. An alternative physical separation method could be used to overcome the AnMBR limitations. Replacing the membrane unit of an AnMBR with a dissolved air flotation (DAF) system, and returning the flotation layer to the anaerobic reactor, may ensure high total suspended solids (TSS) retention while overcoming the membrane limitations. However, the oxygen-saturated flotation layer and the overall introduction of oxygen into the reactor through the DAF may negatively impact the anaerobic conversion process. This dissertation investigates the potential to use an AD coupled with a DAF system (AD-DAF) as a pre-treatment technology, specifically for the treatment of drain- and wastewater that mimics the ever-changing conditions of the Barapullah drain in New Delhi. Since testing an AD-DAF system on a laboratory-scale is not practically feasible, due to the constraints in downscaling a DAF unit, the implications of coupling these two technologies were assessed in two different systems: a column bench-scale DAF unit, and a lab-scale micro-aerated anaerobic membrane bioreactor (MA-AnMBR). To begin with, a data-driven experimental DAF model was developed to predict TSS removal. Input values for the experimental model were particle and bubble characteristics. The experimental model outcomes were verified in a bench-scale column DAF and two full-scale DAF systems. Results showed a predicted TSS removal aligned with the measured one of Delft canal water, anaerobic sludge, and DAF2 influents, 68 ± 1% vs. 66-96%, 77 ± 3% vs. 68-92%, and 98 ± 1% vs. 96± 1%, respectively.Afterwards, the bench-scale DAF was used to investigate the removal of suspended solids under four different influent conditions and seven DAF independent control variables (influent TSS, pH, temperature, DAF particles residence time, white water pressure, coagulants and flocculants concentration and mixing time). The influents simulated the Barapullah drain conditions under 1) dry and 2) monsoon times, and 3) close or 4) far from the pollution source. The results obtained indicated that TSS removal efficiency on the bench-scale DAF unit could mimic a full-scale system and that a DAF can remove over 90% of TSS for the four different tested influents. On the other hand, the effect of the performance variables altered depending on the influent type, with pressure showing a positive influence on the separation efficiency.Secondly, to assess the effect of coupling the DAF system with AD, a lab-scale AnMBR system was subjected to an oxygen load similar to the one used on a DAF unit. The effects of the oxygen load were compared to a fully anaerobic system, and the MA-AnMBR performance was assessed, for removal of organic matter, biogas production, nutrient concentration, operation and maintenance, and removal of two antibiotics sulfamethoxazole, SMX, and trimethoprim, TMP). Results showed a slight significant increase in COD removal, from 98.2 to 98.5%, and an increase of 35% in the ammonium concentration in the MA-AnMBR permeate, which indicated improved hydrolysis. Furthermore, biogas production decreased by 27%, but methane concentration on both MA-AnMBR and AnMBR was high (85%). Micro-aeration of the AnMBR had no negative effect in the removal of the tested antibiotics, which have a preferred anaerobic degradation pathway. TMP was rapidly adsorbed onto the sludge biomass and then degraded due to the long solids’ retention time (27 days). SMX adsorption was minimal, but the system hydraulic retention time of 2.6 days allowed its biodegradation. The addition of SMX and TMP led to an increase in the relative abundance of all studied anti-microbial resistant genes (ARGs) ( sul1, sul2, and dfrA1) and one mobile genetic element (intI1) in the MA-AnMBR sludge. Furthermore, the presence of antibiotic-resistant bacteria and antibiotic-resistance genes in the reactor permeate indicated that further treatment was needed. The outcomes obtained in this dissertation showed that an AD-DAF system has the potential to effectively remove total suspended solids under different influent conditions, and that the added oxygen load could improve hydrolysis with minimal impacts on the anaerobic conversion processes.Sanitary Engineerin
Comparison of two doses and two routes of administration of misoprostol after pre-treatment with mifepristone for early pregnancy termination
No full textAbstract Background It is not known whether a 400 μg dose of misoprostol has a similar efficacy as an 800 μg dose when administered sublingually or vaginally 24 hours after 200 mg mifepristone. Methods It is proposed to undertake a placebo-controlled, randomized, non-inferiority trial (3% margin of equivalence) of the two misoprostol doses when administered sublingually or vaginally using factorial design. A total of 3008 pregnant women ( The four treatment regimens will be compared in terms of: (i) their efficacy to induce complete abortion; (ii) induction-to-abortion interval when possible; (iii) the frequency of side effects; and (iv) women's perceptions. The initial judgment of the outcome of treatment is made at the follow-up visit on day 15 of the study and the final assessment four weeks later. It is estimated that the clinical phase will require 12–14 months for data collection. To compare the two routes and two doses, relative risks (RR) of failure to achieve a complete abortion and failure to terminate pregnancy and the two-sided 95% CIs will be calculated by standard methods, as well as risk differences and two-sided 95% CIs. The latter will be used to test the non-inferiority hypotheses (at 2.5% level of significance) for achieving complete abortion. The factorial structure will be taken into account in the analysis after testing the interaction. Trial registration ISRCTN87811512</p
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