Preliminary weight sizing of light pure-electric and hybrid-electric aircraft

Abstract The lack of consolidated preliminary design techniques coping with the characteristics of most recent electric and hybrid-electric power plants is often an obstacle for aircraft manufacturers and for owners and operators as well, making the design process less straightforward and hampering comparisons with respect to more traditional designs. In this paper, a technique for the preliminary weight sizing of electric aircraft in the General Aviation category is explained. This is based on existing procedures typical to conventionally-powered aircraft, integrated in a common framework to suitably tackle the issues raised by the peculiar features of electrically-powered aircraft. Then, an expansion of the design method to the case of a series hybrid propulsion system is investigated. Results in virtual environment on a realistic design are also presented

An observation methodology for non-measurable rotorcraft states

In an attempt to reduce acoustic pollution due to terminal flight phases (lift-offs and landings) in the surroundings of heliport, project MANOEUVRES developed a device capable of estimating the acoustic footprint of helicopters on the ground. This device requires knowledge of certain quantities that cannot be directly measured through physical sensors: the tip-path plane angle of attack and the main rotor thrust coefficient. Previous research has demonstrated that these quantities can be accurately estimated using observers that are properly fed with directly measurable flight mechanics and rotor state variables. However, these observers, which are based on linear mathematical models identified offline and employed through interpolation with respect to nominal airspeed, have shown poor robustness when the number of identification input cases is reduced, as required for a realistic design of observers in the field. This issue has particularly emerged when non-trimmed manoeuvres were considered during observation testing. To address this issue, this paper introduces a new baseline for the observation model, which includes dynamic pressure as an additional input. Moreover, a different model structure is considered depending on the observed variable. Specifically, for the tip-path plane angle of attack, a single model covers the entire airspeed range, while observation models for the rotor thrust coefficient are interpolated based on flight altitude. This new approach demonstrates results of comparable or superior quality to previous observation models. Furthermore, it exhibits increased robustness when the pool of identification cases used for observer synthesis is significantly reduced. Such improved performance and ease of synthesis pave the way for the setup and adoption of the proposed observers in the field

Innovative Helicopter In-Flight Noise Monitoring Systems Enabled by Rotor-State Measurements

The present contribution aims at providing a comprehensive illustration of a new approach to rotorcraft noise abatement, especially during terminal procedures, when the vehicle approaches the ground and the acoustic impact is higher. This approach pursues the development of technologies and tools for real-time, in-flight monitoring of the emitted noise. The effect of the acoustic radiation is presented to the pilot in a condensed, practical form on a new cockpit instrumentation, the Pilot Acoustic Indicator (PAI), to be used for performing quieter maneuvers. The PAI is based on the synergetic composition of pre-calculated acoustic data, which are used in a noise estimation algorithm together with the data gathered by an innovative contactless measurement system, capable of acquiring the main rotor blade motion. The paper reports on the current studies in unsteady and quasi-steady aeroacoustic prediction and tip-path-plane angle of attack and thrust coefficient observation. Results on novel methodologies are discussed, together with the main features of the PAI design and development process

Pet pyometra : correlating bacteria pathogenicity to endometrial histological changes

Pyometra is a life-threatening infectious disease that frequently affects bitches and queens. Although histopathological patterns of pyometra have been extensively explored, the microbiological aspects, such as bacteria pathogenicity, have not been correlated to microscopy endometrial lesions so far. In this study, these two pathological aspects of pyometra were analysed and correlated. Uterus fragments and intrauterine content samples were collected from pets diagnosed with pyometra (30) and submitted to histopathology analysis and bacterial culture, respectively. The degree of endometrial histopathological lesions in pyometra cases were classified as mild, moderate and severe. Thirty different bacteria isolates were identified from intrauterine content culture. Escherichia coli(E. coli) was pure isolated in 57.7% and highly related to severe endometrial lesions. Immunohistochemistry assay revealed the adhesion and invasion of this bacteria agent to the injured endometrium. Virulence aspects of these E. coli strains were explored, demonstrating biofilm formation ability and a set of virulence genes in most isolates. These results support the adaptive genetic and phenotypic advantages of E. coli for uterus infection, and justify the high frequency of this agent involved in pyometra cases

Measurement of Glutathionylated Haemoglobin by MALDI-ToF Mass Spectrometry as a Biomarker of Oxidative Stress in Heavy Smokers and in Occupational Obese Subjects

Glutathionyl-haemoglobin (Hb-SSG) is a minor form of haemoglobin characterized by the presence of a disulfide bond between the β-93 cysteine residue and the thiol group of glutathione. Hb-SSG is naturally present in the erythrocytes at levels comparable to those of glycated haemoglobin and can be measured by MALDI mass spectrometry on very small samples of erythrocytes from peripheral blood. Since Hb-SSG has been recognized as a sensitive biomarker of oxidative stress in several degenerative diseases (diabetes, hyperlipidemia, kidney disease) and in healthy workers exposed to glutathione-depleting toxic agents such as butadiene, we have measured for the first time the levels of Hb-SSG in two groups: healthy heavy cigarette smokers and overweight-obese

First diagnosis of multisystem inflammatory syndrome in children (MIS-C): an analysis of PoCUS findings in the ED

Children with multisystem inflammatory syndrome (MIS-C) tend to develop a clinical condition of fluid overload due both to contractile cardiac pump deficit and to endotheliitis with subsequent capillary leak syndrome. In this context, the ability of point-of-care ultrasound (PoCUS) to simultaneously explore multiple systems and detect polyserositis could promote adequate therapeutic management of fluid balance. We describe the PoCUS findings in a case-series of MIS-C patients admitted to the Emergency Department. At admission 10/11 patients showed satisfactory clinical condition without signs and symptoms suggestive for cardiovascular impairment/shock, but PoCUS showed pathological findings in 11/11 (100%). In particular, according to Rapid Ultrasound in SHock (RUSH) protocol, cardiac hypokinesis was detected in 5/11 (45%) and inferior vena cava dilatation in 3/11 (27%). Peritoneal fluid was reported in 6/11 cases (54%). Lung ultrasound (LUS) evaluation revealed an interstitial syndrome in 11/11 (100%), mainly localized in posterior basal lung segments. We suggest PoCUS as a useful tool in the first evaluation of children with suspected MIS-C for the initial therapeutic management and the following monitoring of possible cardiovascular deterioration

Offline and online LSTM networks for respiratory motion prediction in MR-guided radiotherapy

Objective. Gated beam delivery is the current clinical practice for respiratory motion compensation in MR-guided radiotherapy, and further research is ongoing to implement tracking. To manage intra-fractional motion using multileaf collimator tracking the total system latency needs to be accounted for in real-time. In this study, long short-term memory (LSTM) networks were optimized for the prediction of superior–inferior tumor centroid positions extracted from clinically acquired 2D cine MRIs. Approach. We used 88 patients treated at the University Hospital of the LMU Munich for training and validation (70 patients, 13.1 h), and for testing (18 patients, 3.0 h). Three patients treated at Fondazione Policlinico Universitario Agostino Gemelli were used as a second testing set (1.5 h). The performance of the LSTMs in terms of root mean square error (RMSE) was compared to baseline linear regression (LR) models for forecasted time spans of 250 ms, 500 ms and 750 ms. Both the LSTM and the LR were trained with offline (offline LSTM and offline LR) and online schemes (offline+online LSTM and online LR), the latter to allow for continuous adaptation to recent respiratory patterns. Main results. We found the offline+online LSTM to perform best for all investigated forecasts. Specifically, when predicting 500 ms ahead it achieved a mean RMSE of 1.20 mm and 1.00 mm, while the best performing LR model achieved a mean RMSE of 1.42 mm and 1.22 mm for the LMU and Gemelli testing set, respectively. Significance. This indicates that LSTM networks have potential as respiratory motion predictors and that continuous online re-optimization can enhance their performance

Methodologies for the initial design studies of an innovative community-friendly miniliner

The present paper illustrates some of the strategies adopted to set the top-level aircraft requirements for an innovative near-zero emission miniliner. This novel 19-seater is conceived to provide a micro-feeder service, devised to exploit the existing European network of small local airports and airfields as feeders to hubs, as well as an intercity service to enhance connections between destinations that are not served by efficient ground transportation. First, a survey of the current network of airports and airfields is carried out and the existing ground transportation is analysed. Secondly, the potential demand for the microfeeder and intercity services is estimated based on the assessment of the time advantage between ground based means of transport and the miniliner option. Application examples in different geographic contexts provide useful information for the definition of crucial design requirements such as payload, range, runway length, and cruising airspeed

Observing the Angle of Attack of the Tip-Path Plane from Rotor Blade Measurements

A recurring problem in helicopters is the difficulty to accurately measure the angle of attack of the airframe and tip-path plane with respect to the slipstream. Differently from fixed wing aircraft, it is hard to find a spot on the airframe of a helicopter where the velocity vector of the stream is not polluted by a very relevant downwash component due to the deflecting action of the main rotor on the air stream. Furthermore, the geometrical definition of the tip-path plane calls for the knowledge of the attitude of the blades with respect to a plane normal to the main rotor mast. This attitude is related to the flap motion of the blades, which to this time cannot be measured effectively through a direct measurement method. Building on the experience and research results of the MANOEUVRES project, which is aimed at developing a novel sensor for the flap motion of the blades, making possible monitoring the noise intensity emitted by the helicopter during approach maneuvers, this paper presents a possible way to estimate the angle of attack of the tip-path plane starting from a basic set of measurements including those related to the flapping angle of the blades. The knowledge of the flap motion of the blades allows to observe also other flight mechanics performance parameters, like the thrust force coefficient, without the need for further sensor information. Support for the feasibility of the proposed observer comes from the well known equations for the flapping blade. The presented results assessing the quality of the synthesized observer and its ability to work under both design and off-design conditions have been obtained working on the virtual model of an existing machine