Decision-making for unmanned aerial vehicle operation in icing conditions

With the increased use of unmanned aerial systems (UAS) for civil and commercial applications, there is a strong demand for new regulations and technology that will eventually permit for the integration of UAS in unsegregated airspace. This requires new technology to ensure sufficient safety and a smooth integration process. The absence of a pilot on board a vehicle introduces new problems that do not arise in manned flight. One challenging and safety-critical issue is flight in known icing conditions. Whereas in manned flight, dealing with icing is left to the pilot and his appraisal of the situation at hand; in unmanned flight, this is no longer an option and new solutions are required. To address this, an icing-related decision-making system (IRDMS) is proposed. The system quantifies in-flight icing based on changes in aircraft performance and measurements of environmental properties, and evaluates what the effects on the aircraft are. Based on this, it determines whether the aircraft can proceed, and whether and which available icing protection systems should be activated. In this way, advice on an appropriate response is given to the operator on the ground, to ensure safe continuation of the flight and avoid possible accidents

Transient hypercortisolism and symptomatic hyperthyroidism associated to primary hyperparathyroidism in an elderly patient: case report and literature review.

Abstract Background: Primary hyperparathyroidism (PHPT) is often found on routine blood tests, at a relatively asymptomatic stage. However many studies suggest different systemic effects related to PHPT, which could be enhanced by an abnormal cortisol release due to chronic stress of hyperparathyroidism. Being PHPT frequently found in the 6th to 7th decade of life, a careful and multifaceted approach should be taken. Case presentation: We report the case of an elderly patient with symptomatic PHPT and incidental pulmonary embolism. He was treated with hydration, zoledronic acid, cinacalcet and high-dose unfractionated heparin. Parathyroid surgery was successfully performed, but patient's conditions suddenly worsened because of a transient thyrotoxicosis, probably induced by a previous exposure to iodine load and/or thyroid surgical manipulation. A short-term treatment with beta-blockers was introduced for symptomatic relief. The patient also presented a transient hypercortisolism with elevated ACTH, likely due to stress related not only to aging and hospitalization but also to PHPT, resolved only four months after parathyroid surgery. Conclusion: Chronic hyperparathyroidism has been linked with increased all-cause mortality. A functional chronic hypercortisolism could be established, enhancing PHPT related disorders. Only parathyroid surgery has been demonstrated to cure PHPT and complications related, showing similar outcome between older and younger patients. However, the management of post-operative period should be more careful in fragile patients. In particular, the early diagnosis and treatment of a transient post-operative thyrotoxicosis could improve recovery. Due to the increase in prevalence and the evidence of many related complications even in asymptomatic PHPT, expert opinion-based guidelines for surgical treatment of PHPT should be developed especially for elderly patients

Evaluation of the flow resistance in mobile bed vegetated rivers

River hydrodynamicsBed roughness and flow resistanc

Dynamic impact of a water and sediments surge against a rigid wall

The paper addresses the dynamic impact of channel flows of water and mixtures of water and sediments on a test wall. Two types of impact may occur: the first characterized by the formation of a complete reflected wave moving upstream; the second type consisting in the vertical deviation of the flow along the wall with a jet-like behaviour. The paper deepens this second type of impact. During the impact of the flow against the wall, the pressure distribution along the wall and the impact force were measured. In order to explain the phenomenon, a rational approach based on the conservation equations for mass, momentum and energy was adopted; from this approach some simplified solutions were derived. We discuss the possible effects of the impact of single gravel particles and the influence of the dimensionless groups that govern the phenomenon. A good agreement between the experimental data and the results of the theoretical approach was obtained

drag forces in statistically stationary and homogeneous submerged granular flows

n/

Analisi di un database di una palestra padovana: andamento e previsioni

openPer problemi con il pdf inviare e-mail a [email protected]

Validation of Collision Detection and Avoidance Methods for Urban Air Mobility through Simulation

Urban Air Mobility is a new concept of regional aviation that has been growing in popularity as a solution to the issue of ever-increasing ground traffic. Electric vehicles with vertical take-off and landing capabilities are being developed by numerous market companies as a result of the push toward environmentally sustainable aviation. The next stage in the eVTOL development process would be to define the concept of operation of these conceptual aircraft and then to integrate them with the existing airspace once they are airborne. In addition to coordinating with conventional air traffic and other Urban Air Mobility (UAM) vehicles, collision avoidance with uncooperative airspace users has to be addressed. Birds and drones of all sizes could be dangerous for these low-flying aircraft. Innovative collision detection and avoidance techniques need to be employed due to the uncooperative nature of these airspace users and different performance characteristics of urban air mobility vehicles compared to classical fixed-wing aircraft. The aim of this study is to validate one such system by means of fast-time solutions. This system uses a decision tree and safety envelopes to prevent collisions with non-cooperative airspace members. The system is designed to work with different aircraft configurations used for Urban Air Mobility (UAM) operations. Various scenarios are modelled by varying intruder type, location, flight path among others. Changes in flight time and closest point of approach are assessed to evaluate the system with regard to safety and efficiency

Perceptions et représentations de l’«engagement» chinois en Amérique latine : l’image médiatique de la Chine au Panama en 2017

Le retour de la puissance chinoise se traduit par un engagement multidimensionnel croissant sur la scène internationale ; c’est le cas en Amérique latine. La littérature académique s’intéresse principalement à l’impacts économique de l’engagement chinois dans la région. Elle révèle des déséquilibres quantitatifs et sectoriels au sens des relations entre la Chine et l’Amérique latine. Toutefois, peu d’articles semblent traiter de la manière dont les acteurs latinoaméricains perçoivent cet engagement et ces déséquilibres. Ce mémoire se propose d’étudier les perceptions et représentations publiques de l’engagement chinois dans un état d’Amérique centrale : le Panama. Cette étude de cas portera sur la version numérique d’un quotidien panaméen, La Estrella de Panama ; elle se propose d’analyser l’image médiatique de la Chine au cours de l’année 2017. Elle confirme que la Chine est devenue une sujet significatif de l’espace médiatique latino-américain. Elle jouit d’une couverture multidimensionnelle, et bénéficie d’une image fortement positive, malgré les profonds déséquilibres économiques dans ses relations avec l’Amérique latine et le Panama. Ce paradoxe s’explique par une surreprésentation d’informations positives, et une analyse insuffisante des écueils de l’engagement chinois. Les intérêts économiques amènent le Panama à faire la promotion des relations avec la RPC, malgré les défis qu’elles soulèvent pour les autres acteurs régionaux.China’s rise comes with an worldwide and increasing multidimensional engagement. That happens to be the case in Latin America. Academic literature is mainly concerned with the economic implications of this engagement. It shows quantitative and sectoral imbalances within the economic relations between the PRC and Latin America. Research is still to be broadened on how Latin America perceives this engagement. This paper aims to study how it is perceived and depicted in a Central American state : Panama. This research will be based on the digital version of a Panamanian newspaper, La Estrella de Panama, and it will cover China’s media image in 2017. This Master’s thesis shows that China has become a significant media subject in Latin America. The country gets a multidimensional coverage, and a highly positive image, despite deep imbalances within its economic relations with both Latin America and Panama. This paradox is based on a disproportionate number of positive information, together with an insufficient analysis of the drawbacks of the Chinese engagement. Economic interests lead Panama to promote relations with China, regardless of the challenges they raise in the region

Analysis of a fluvial groynes system on hydraulic scale model

River morphodynamics and sediment transportSediment-structure interactio