288 research outputs found

    The Group of Responsables Flight Mechanics, Systems and Integration (GoR FM): An Overview of Activities and Success Stories

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    This paper gives an overview of the activities of the Group of Responsables for Flight Mechanics, Systems and Integration (GopR FM) within GARTEUR (Group for Aeronautical Research and Technology in EURope) over nearly half a century of European collaboration. It presents the research fields, some very successful highlights and gives an outlook on future activities

    Enabling LPV for GLS Equipped Aircraft Using a SBAS to GBAS Converter

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    We build a prototype system intended to bring together the advantages of both the ground based and satellite based augmentation systems (GBAS, SBAS). It combines an SBAS-capable global navigation satellite systems receiver with a database and a GBAS-compatible data link. The correction and integrity data received from the SBAS satellite are automatically translated into GBAS-compatible structures and sent to the airborne multi-mode receiver using the final approach segment data block. As commercial air transport aircraft are rarely equipped with SBAS capable receivers but are increasingly fitted with GBAS receivers our System adds the SBAS capability to a GBAS equipped aircraft. Here, we present data collected during airline trials in the summer of 2022

    Treatment of critical bone defects using calcium phosphate cement and mesoporous bioactive glass providing spatiotemporal drug delivery

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    Calcium phosphate cements (CPC) are currently widely used bone replacement materials with excellent bioactivity, but have considerable disadvantages like slow degradation. For critical-sized defects, however, an improved degradation is essential to match the tissue regeneration, especially in younger patients who are still growing. We demonstrate that a combination of CPC with mesoporous bioactive glass (MBG) particles led to an enhanced degradation in vitro and in a critical alveolar cleft defect in rats. Additionally, to support new bone formation the MBG was functionalized with hypoxia conditioned medium (HCM) derived from rat bone marrow stromal cells. HCM-functionalized scaffolds showed an improved cell proliferation and the highest formation of new bone volume. This highly flexible material system together with the drug delivery capacity is adaptable to patient specific needs and has great potential for clinical translation

    Virtual Cockpit Instruments - How Head-Worn Displays Can Enhance the Obstacle Awareness of Helicopter Pilots

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    The rise of augmented reality glasses and related technologies offers new possibilities for the human-machine interface design of future aircraft. Today, head-worn displays (HWDs) are mainly used by military pilots, for instance by helicopter crews for low-visibility operations close to ground and obstacles. Nevertheless, recent technological advances in this area allow the prediction that these systems could become available for more pilots in the future. This article presents a concept how state-of-the-art HWD symbology can be expanded to get even more out of the advantages of this technology. With so-called "virtual cockpit instruments" (VCIs), an HWD can show information, which is conventionally rendered on panel-mounted displays. These VCIs can be imagined as virtual display screens, which can be positioned freely around the pilot. Their major benefit is that they create many new options for the design of a flexible, situation-adaptive cockpit environment. This article introduces the general concept and presents several options how such an approach can be put into practice. Here, the concept is applied to helicopter operations in offshore windparks. We implemented a VCI-adapted obstacle awareness display and assessed a set of positioning variants for the new VCI. Two simulator studies -- with 11 and 7 participants -- provide interesting insights on the realization of this concept. In addition to high subjective ratings, the VCI significantly increased the pilot's head-up, eyes-out time -- an important measure for challenging maneuvers close to obstacles. Overall, this article illustrates a promising concept for the human-machine interface design of future cockpits and discusses its potentials and limitations

    GNSS Double Differences used as Beacon Landing System for Aircraft Instrument Approach

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    When using GNSS navigation for final approach guidance of aircraft to a landing site, the only systems currently available are differential GNSS with additional integrity data called augmentation systems. These work well when the landing site is fixed in space and well surveyed. In all other cases, augmentation systems are difficult to use. Here, we propose relative navigation based on GNSS double difference measurement to accomplish the same task, but also onto moving landing platforms or at unsurveyed locations. We call this the Beacon Landing System. Furthermore, we show long term measurement data confirming the sub-meter accuracy and results from flight tests. During the flight test we successfully used the relative navigation for aircraft guidance

    Aircraft Wake Vortex Scenarios Simulation Package - WakeScene

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    Wake-vortex advisory systems and modifications of ATC procedures that aim at increasing airport capacity without compromising safety have been developed in recent years. Prior to the introduction of such systems the associated risks must be assessed. The WakeScene (Wake Vortex Scenarios Simulation) Package allows to assess the encounter probability behind different wake-vortex generating aircraft during approach and landing. WakeScene consists of modules that model traffic mix, aircraft trajectories, meteorological conditions, wake vortex evolution, and potential hazard area. This manuscript introduces the operating sequence of WakeScene, the employed sub-models and data bases, the simulation environment and evaluation tools together with the so far accomplished validation work. Examples of WakeScene applications and an outlook on further developments of the software package conclude the report

    FLIGHT TESTING OF NOISE ABATING RNP PROCEDURES AND STEEP APPROACHES

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    To test different types of noise abatement approach procedures the Institute of Flight Guidance and the Institute of Aerodynamics and Flow Technology performed flight tests on the 6th September 2010 with a Boeing 737-700. In total 13 approaches to the Research Airport in Brunswick were flown while the approach area of the airport was equipped with six noise measurement microphones. Brunswick airport is equipped with an experimental ground based augmentation system (GBAS) which allows the implementation of 48 ILS lookalike precision approach procedures with different approach angles simultaneously

    BK viremia and polyomavirus nephropathy in 352 kidney transplants; risk factors and potential role of mTOR inhibition

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    Background Polyomavirus BK nephropathy (PyVAN) remains an important cause of early graft dysfunction and graft loss in kidney transplantation. Methods In this retrospective, single centre cohort study we studied the incidence and outcome of BK viral infection in 352 patients transplanted in 2008–2011. Results During follow-up viral replication was detected in 48 patients (13.6%); 22 patients (6.2%) had biopsy proven PyVAN. In multivariate logistic regression analyses risk factors for BK-viremia were lack of enrolment into randomized controlled trials (RCTs), biopsy proven acute rejections, cytomegaly virus (CMV) serostatus of both donor and recipient and previous transplantation. In patients without PyVAN reduction or switch of immunosuppression was associated with rapid viral clearance and stable graft function. In contrast, in most patients with PyVAN graft function deteriorated and 5 patients prematurely lost their allograft. Switch of immunosuppression to a low dose cyclosporine plus mTOR inhibitor based regimen in patients with PyVAN was safe, well tolerated and tended to be associated with a better short-term outcome in terms of graft function compared to reduction of existing immunosuppression alone. Conclusions With the lack of licensed anti-polyoma viral drugs reduction or conversion of immunosuppression remains the mainstay of therapy in patients with PyVAN. The combination of low dose cyclosporine plus mTOR inhibition appears to be safe and warrants further investigation

    Paradigms in multiple sclerosis: time for a change, time for a unifying concept

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    It has recently been suggested that, rather than being an autoimmune disease, multiple sclerosis (MS) is an example of a neurocristopathy, a pathological process resulting from a faulty development of the neural crest. Whilst several characteristics of the disease suggest a neurocristopathy, other aetiological factors require consideration, including hygiene-related factors that alter the immune responses to common pathogens resulting in an eclipse of immune reactivity that could protect against MS, the possible role of human endogenous retroviruses (HERVs) in pathogenesis and autoimmune phenomena, HLA polymorphism, vitamin D levels before and after birth and immune repair mechanisms. A postulated aetiological factor in MS, associated with altered vitamin D metabolism and abnormal HERV expression, is a long-lasting disturbed redox regulation in the biosynthesis of a melanoma-like melanin pigment. Although intensive further studies on melanin pigments in nerve tissue in MS are required, the known properties of a pathological form of such pigments in melanoma could explain a number of observations in MS, including the impact of light, UV-light, and vitamin D, and could explain the clinical manifestations of MS on the basis of an oscillating process of oxidative charge and discharge of the pigments and a threshold phenomenon with a change of the quasi-catalytic function of the pigment from destroying reactive oxygen radicals or species to transforming them to more harmful long-persisting highly reactive species. Taken together with the consequences of an adaptive process in partly demyelinated neurons, resulting in an increase in number of mitochondria, and the impact of stressful life events, these conditions are necessary and sufficient to explain the disease process of MS with its spatial (plaques) and temporal (attacks and remissions) characteristics. This suggested unifying concept of the pathogenesis of MS may open perspectives for prevention, diagnosis and therapy. In particular, prevention may be achieved by vaccinating against Epstein-Barr virus in early childhood
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