4,298 research outputs found

    Environmental Impact Assessment, on the Operation of Conventional and More Electric Large Commercial Aircraft

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    Global aviation is growing exponentially and there is a great emphasis on trajectory optimization to reduce the overall environmental impact caused by aircraft. Many optimization techniques exist and are being studied for this purpose. The CLEAN SKY Joint Technology Initiative for aeronautics and Air transport, a European research activity run under the Seventh Framework program, is a collaborative initiative involving industry, research organizations and academia to introduce novel technologies to improve the environmental impact of aviation. As part of the overall research activities, "green" aircraft trajectories are addressed in the Systems for Green Operations (SGO) Integrated Technology Demonstrator. This paper studies the impact of large commercial aircraft trajectories optimized for different objectives applied to the on board systems. It establishes integrated systems models for both conventional and more electric secondary power systems and studies the impact of fuel, noise, time and emissions optimized trajectories on each configuration. It shows the significant change in the fuel burn due to systems operation and builds up the case as to why a detailed aircraft systems model is required within the optimization loop. Typically, the objective in trajectory optimization is to improve the mission performance of an aircraft or reduce the environmental impact. Hence parameters such as time, fuel burn, emissions and noise are key optimization objectives. In most instances, trajectory optimization is achieved by using models that represent such parameters. For example aircraft dynamics models to describe the flight performance, engine models to calculate the fuel burn, emissions and noise impact, etc. Such techniques have proved to achieve the necessary level of accuracy in trajectory optimization. This research enhances previous techniques by adding in the effect of systems power in the optimization process. A comparison is also made between conventional power systems and more electric architectures. In the conventional architecture, the environmental control system and the ice protection system are powered by engine bleed air while actuators and electrics are powered by engine shaft power off-takes. In the more electric architecture, bleed off take is eliminated and the environmental control system and ice protection system are also powered electrically through engine shaft power off takes

    Efficacy of first-line sodium thiosulphate administration in a case of potassium cyanide poisoning

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    Cyanide poisoning may occur following accidental fire-smoke inhalation or deliberate ingestion of salts. Hydroxocobalamin represents a first-line life-saving antidote. Although hydroxocobalamin represents a first-line lifesaving antidote, it is still not promptly available in the emergency department. Sodium thiosulfate can be administered in association with hydroxocobalamin whereas the delayed onset of clinical response makes sodium thiosulfate less suitable for emergency use. We describe a case of cyanide intoxication of a 43-year-old man who ingested an unknown amount of potassium cyanide, purchased via the Internet, in an attempted suicide. At admission to the emergency department, the patient presented GCS 3 with severe lactic acidosis. Orotracheal intubation, gastric lavage and oral activated charcoal were applied. Sodium thiosulfate was available in the emergency department and 10 grams were infused over a 30 minute period. Hydroxocobalamin was prescribed by the poison control centre and 5 grams were infused 2 hours after admission. Following sodium thiosulfate administration the patient was arousable and lactate concentration improved. No adverse effects were noted. Metabolic acidosis completely resolved 12 hours later. Cyanide concentration performed on blood samples collected at admission confirmed high cyanide blood levels (15 mg/L). This report highlights as the first-line administration of sodium thiosulfate, in rapid infusion, resulted effective and safe for cyanide poisoning. Our report suggests that sodium thiosulfate should be considered when hydroxocobalamin is not promptly available in an emergency settin

    GNC architecture solutions for robust operations of a free-floating space manipulator via image based visual servoing

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    On-orbit servicing often requires the use of robotic arms, and a key asset in this kind of operations is autonomy. In this framework, the use of optical devices is a solution, already analyzed in many researches both for autonomous rendezvous and docking and for the evaluation of the control of the manipulator. In the present paper, simulations for assessing the controller performance are realized in a high-fidelity purposely developed software architecture, in which not only the selected 6 DOF space manipulator is modeled, but also a virtual camera, acquiring in the loop images of the target CAD model imported, is included in the GNC loop. This approach allows to emphasis several problems that would not emerge in simulations with images characterized by easily-identifiable, purposely-created markers. At the scope, a specific GNC architecture is developed, based on finite-state machine logic. According to this approach, two different Image Based Visual Servoing strategies are alternatively performed, commanding only linear or angular velocity of the camera, switching between the two control techniques when the “stack” or “divergence” condition is triggered. In this way a stable and robust accomplishment of the tasks is achieved for many configurations and for different target models

    Virtual Reality to Simulate Visual Tasks for Robotic Systems

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    Virtual reality (VR) can be used as a tool to analyze the interactions between the visual system of a robotic agent and the environment, with the aim of designing the algorithms to solve the visual tasks necessary to properly behave into the 3D world. The novelty of our approach lies in the use of the VR as a tool to simulate the behavior of vision systems. The visual system of a robot (e.g., an autonomous vehicle, an active vision system, or a driving assistance system) and its interplay with the environment can be modeled through the geometrical relationships between the virtual stereo cameras and the virtual 3D world. Differently from conventional applications, where VR is used for the perceptual rendering of the visual information to a human observer, in the proposed approach, a virtual world is rendered to simulate the actual projections on the cameras of a robotic system. In this way, machine vision algorithms can be quantitatively validated by using the ground truth data provided by the knowledge of both the structure of the environment and the vision system

    particle size evaluation of total mixed rations in intensive beef production systems

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    AbstractSamples of total mixed ration (TMR) were collected periodically in 15 beef cattle farms and submitted to a nutritional and particle size evaluation. Samples of faeces were taken and analysed for pH, consistency, colour and visually ranked for corn residues (Corn Residue Index) from 4 (totally digested) to 0 (very high presence of maize residues). Dry matter (DM), crude protein (CP), and ash content of TMR for Limousine were higher than that for Charolaise while an opposite situation was observed for crude fiber (CF). Particle size analysis of TMR showed an higher content of small ( 19.0 mm) particles in Charolaise than in Limousine TMR. From May to September a general increase of larger fractions and a reduction of the smaller ones were observed, as a consequence of empirical practices of TMR formulation during summer. Faeces characteristics did not show any difference between breeds (overall mean pH: 6.00 vs 6.13; Corn Residue Index: 2.90 vs 3.24, respectively for Charolaise a..

    A mass spectrometric study on tannin degradation within dyed woolen yarns

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    Natural tannins from various plants have been used throughout human history in textile dyeing, often as mordant dyes. The ageing behavior of these dyes is a challenge in conservation science, requiring a thorough knowledge of the textile–mordant-dye system. In this work, we analyzed reference wool yarns dyed with natural tannins from oak gallnuts, walnut (Juglans regia), and catechu (Acacia catechu), after artificial ageing. To gain insights on the composition of the dyestuffs and on how they aged, an analytical procedure based on extraction with Na2EDTA/DMF (ethylenediaminetetraacetic acid/dimethylformamide) and high-performance liquid chromatography (HPLC) analysis using high-resolution mass spectrometry detection was used. Since conventional reversed-phase (RP) columns usually show poor retention efficiency of highly polar compounds such as tannins, an RP-amide embedded polar group stationary phase was used to achieve optimal retention of the most polar compounds. Tannins from oak gallnuts showed little degradation after ageing, while a significant increase in the content of hydroxybenzoic acids was observed for tannins from walnut and catechu. Finally, the analytical procedure was applied to characterize the tannin dyes in historical tapestries from the 15th to 16th century, and the results were discussed in comparison with the reference yarns

    Facility for validating technologies for the autonomous space rendezvous and docking to uncooperative targets

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    We present the latest advancements in the air-bearing facility installed at La Sapienza’s GN Lab in the School of Aerospace Engineering. This facility has been utilized in recent times to validate robust control laws for simultaneous attitude control and vibration active damping. The instrumentation and testbed have been restructured and enhanced to enable simulations of close proximity operations. Relative pose determination, accomplished through visual navigation as either an auxiliary or standalone system, is the first building block. Leveraging the acquired knowledge, optimal guidance and control algorithms can be tested for contactless operations (e.g. on-orbit inspection), as well as berthing and docking tasks

    Morphologic and genetic characterisation of Corsican and Sardinian trout with comments on Salmo taxonomy

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    Both morphological and molecular data are presented and discussed for indigenous Salmo sp. from Corsica and Sardinia, here called Tyrrhenian trout. For comparison, morphological data obtained from museum specimens, including the Algerian S. macrostigma, are discussed in the light of recent and new molecular findings. In total, 29 measurements and 20 meristic characters were taken from each specimen. Out of the meristic characters, 12 were obtained by means of X-ray. One important morphometric character in the present study is the size of the head measured from premaxilla to posterior margin of preoperculum. This character was particularly stable in all Tyrrhenian trout, showing relatively large head compared to Atlantic trout and to S. macrostigma. On the contrary, other characters like body punctuations, black and white edges of fins, body depth or number of epurals in the caudal skeleton are quite polymorphic. In certain meristic characters, range of variation of Tyrrhenian trout even exceeds that of the extensive comparative material. Each trout has been genetically characterized. New haplotypes from Tyrrhenian trout were discovered, belonging to three mitochondrial lineages viz. Adriatic, marble and Mediterranean, however, Adriatic haplotypes are dominant. Comparing morphological and genetic data, observed morphology lacks any obvious correlation to mitochondrial lineages and it is concluded that Tyrrhenian trout show no particular affinity to S. macrostigma from Algeria
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