154 research outputs found

    Prediction of dynamic pairwise wake vortex separations for approach and landing

    Get PDF
    Design and performance of the Wake Vortex Prediction and Monitoring System WSVBS are described. The WSVBS has been developed to tactically increase airport capacity for approach and landing on single runways as well as closely-spaced parallel runways. It is thought to dynamically adjust aircraft separations dependent on weather conditions and the resulting wake vortex behavior without compro-mis>ing safety. Dedicated meteorological instrumentation and short-term numerical terminal weather prediction provide the input to the prediction of wake-vortex behavior and respective safety areas. LIDAR monitors the correctness of WSVBS predictions in the most critical gates at low altitude. The WSVBS is integrated in the arrival manager AMAN of DLR. Performance tests of the WSVBS have been accomplished at Frankfurt airport in winter 2006/07 and at Munich Airport in summer 2010. Aircraft separations for landings on single runways have been compared employing the concepts of either heavy-medium weight class combinations or dynamic pairwise separations where individual aircraft type pairings are considered. For the very conservative baseline setup of the WSVBS the potential capacity gains of dynamic pairwise operations for single runways appear to be very small. On the other hand, the consideration of individual aircraft types and their respective wake characteristics may almost double the fraction of time when radar separation could be applied

    Collaborative Development of Informal Processes

    Get PDF

    600-GHz Electronically Tunable Vector Measurement System

    Get PDF
    A compact, high-dynamic-range, electronically tunable vector measurement system that operates in the frequency range from approximately 560 to approximately 635 GHz has been developed as a prototype of vector measurement systems that would be suitable for use in nearly-real-time active submillimeter-wave imaging. As used here, 'vector measurement system" signifies an instrumentation system that applies a radio-frequency (RF) excitation to an object of interest and measures the resulting amplitude and phase response, relative to either the applied excitatory signal or another reference signal related in a known way to applied excitatory signal

    FORWARD DYNAMICS FOR THE EVALUATION OF PRACTICAL PROBLEMS IN SPORTS

    Get PDF
    INTRODUCTION: In athletic movements there are often situations where one cannot rate varying executions, because the effects of single actions are unknown. At a tennis stroke for example, the movement of the ball after hitting is well visible as an effect of the action. However, the conditions at hitting the ball and the actions that lead to the torque of hitting are not reliably visible. Their interpretation is only subjective. Nevertheless, the trainer and the player have to give statements of the muscular activity like "hold the racket loosely or firmly "or"relax or stiffen your wrist." This paper focuses on a controversial problem: the use of the wrist in tennis. Some favor a firm wrist, others an actively moving wrist. The group which favors the active wrist based their idea on the higher velocities of the racket head. For this idea biomechanical considerations are only based on kinematic data and on analysis in muscular physiology (see KLEINÖDER 1997, ELLIOT 1991, HUIJING 1994, KOMI 1994) and not on kinetic analysis. With this work we try to fill these gaps with computer simulation. In a similar way we worked on a problem in gymnastics: the increase of swings on the horizontal bar, which is necessary for all swing elements. Little work has been done in this area (see BAUER 1976, BÖHM1997 and WIEMANN 1993). Nevertheless, the research that allows a development of a general theory of the swing increase is lacking (except for the efforts of WIEMANN). The goal of this paper is to show that computer simulation can be a first step towards the development of such a theory

    Nitrate and nitrite variability at the seafloor of an oxygen minimum zone revealed by a novel microfluidic in-situ chemical sensor

    Get PDF
    Microfluidics, or lab-on-a-chip (LOC) is a promising technology that allows the development of miniaturized chemical sensors. In contrast to the surging interest in biomedical sciences, the utilization of LOC sensors in aquatic sciences is still in infancy but a wider use of such sensors could mitigate the undersampling problem of ocean biogeochemical processes. Here we describe the first underwater test of a novel LOC sensor to obtain in situ calibrated time-series (up to 40 h) of nitrate+nitrite (ΣNOx) and nitrite on the seafloor of the Mauritanian oxygen minimum zone, offshore Western Africa. Initial tests showed that the sensor successfully reproduced water column (160 m) nutrient profiles. Lander deployments at 50, 100 and 170 m depth indicated that the biogeochemical variability was high over the Mauritanian shelf: The 50 m site had the lowest ΣNOx concentration, with 15.2 to 23.4 μM (median=18.3 μM); while at the 100 site ΣNOx varied between 21.0 and 30.1 μM over 40 hours (median = 25.1μM). The 170 m site had the highest median ΣNOx level (25.8 μM) with less variability (22.8 to 27.7 μM). At the 50 m site, nitrite concentration decreased fivefold from 1 to 0.2 μM in just 30 hours accompanied by decreasing oxygen and increasing nitrate concentrations. Taken together with the time series of oxygen, temperature, pressure and current velocities, we propose that the episodic intrusion of deeper waters via cross-shelf transport leads to intrusion of nitrate-rich, but oxygen-poor waters to shallower locations, with consequences for benthic nitrogen cycling. This first validation of an LOC sensor at elevated water depths revealed that when deployed for longer periods and as a part of a sensor network, LOC technology has the potential to contribute to the understanding of the benthic biogeochemical dynamics

    Плазменное получение тепловой энергии из сульфатного лигнина

    Get PDF
    This article shows an overview and analysis of the literature on methods of using sludge lignin. This product obtained after treatment of pulp. As a result of calculating the optimum composition of water, organic materials with mechanical impurities from the adiabatic combustion temperature of about 1200 K were determined. Using the obtained results of experimental studies have been carried out in a plasma reactor of the catalytic reactor and has been optimized. The obtained results can be used to create industrial enterprises based on plasma catalytic reactors for waste sludge lignin for the purpose of obtaining heat

    Biodiversity patterns of dry grasslands in the Central Apennines (Italy) along a precipitation gradient : experiences from the 10th EDGG Field Workshop

    Get PDF
    The 10th EDGG Field Workshop took place in a sector of the Central Apennine Mountains, Italy, in June 2017. Altogether, 22 researchers from nine European and Asian countries attended this Field Workshop. We sampled plant and insect biodiversity in submontane and lower-montane grasslands along a precipitation gradient, from the L’Aquila valley and the Fucino basin to the “Abruzzo, Lazio & Molise” National Park. The standardized EDGG sampling protocol, involving nested-plot series and additional 10-m2 relevés, was used. In the course of seven days of intensive fieldwork, we sampled 20 biodiversity plots along with 57 additional normal plots (yielding a total dataset of 97 10-m2 plots). Methodological additions tested in this workshop included the assessment of observer-related error (around 12% of the 10-m2 plots was resurveyed by a different team). In all plots, vascular plants, bryophytes and lichens were sampled. At each nested-plot series, also insects (Auchenorrhyncha) were sampled by local specialists, who developed an ad-hoc sampling procedure

    Differential involvement of forearm muscles in ALS does not relate to sonographic structural nerve alterations

    Get PDF
    We aimed to assess whether differential peripheral nerve involvement parallels dissociated forearm muscle weakness in amyotrophic lateral sclerosis (ALS).The analysis comprised 41 ALS patients and 18 age-, sex-, height- and weight-matched healthy controls. Strength of finger-extension and -flexion was measured using the Medical Research Council (MRC) scale. Radial, median and ulnar nerve sonographic cross-sectional area (CSA) and echogenicity, expressed by the hypoechoic fraction (HF), were determined.In ALS, finger extensors were significantly weaker than finger flexors. Sonographic evaluation revealed peripheral nerve atrophy, affecting various nerve segments in ALS. HF was unaltered.This systematic study confirmed a long-observed physical examination finding in ALS - weakness in finger-extension out of proportion to finger-flexion. This phenomenon was not related to any particular sonographic pattern of upper limb peripheral nerve alteration.In ALS, dissociated forearm muscle weakness could aid in the disease's diagnosis. Nerve ultrasound did not provide additional information on the differential involvement of finger-extension and finger-flexion strength

    ReSurveyGermany: Vegetation-plot time-series over the past hundred years in Germany

    Get PDF
    Vegetation-plot resurvey data are a main source of information on terrestrial biodiversity change, with records reaching back more than one century. Although more and more data from re-sampled plots have been published, there is not yet a comprehensive open-access dataset available for analysis. Here, we compiled and harmonised vegetation-plot resurvey data from Germany covering almost 100 years. We show the distribution of the plot data in space, time and across habitat types of the European Nature Information System (EUNIS). In addition, we include metadata on geographic location, plot size and vegetation structure. The data allow temporal biodiversity change to be assessed at the community scale, reaching back further into the past than most comparable data yet available. They also enable tracking changes in the incidence and distribution of individual species across Germany. In summary, the data come at a level of detail that holds promise for broadening our understanding of the mechanisms and drivers behind plant diversity change over the last century

    Ecological Indicator Values for Europe (EIVE) 1.0

    Get PDF
    Aims: To develop a consistent ecological indicator value system for Europe for five of the main plant niche dimensions: soil moisture (M), soil nitrogen (N), soil reaction (R), light (L) and temperature (T). Study area: Europe (and closely adjacent regions). Methods: We identified 31 indicator value systems for vascular plants in Europe that contained assessments on at least one of the five aforementioned niche dimensions. We rescaled the indicator values of each dimension to a continuous scale, in which 0 represents the minimum and 10 the maximum value present in Europe. Taxon names were harmonised to the Euro+Med Plantbase. For each of the five dimensions, we calculated European values for niche position and niche width by combining the values from the individual EIV systems. Using T values as an example, we externally validated our European indicator values against the median of bioclimatic conditions for global occurrence data of the taxa. Results: In total, we derived European indicator values of niche position and niche width for 14,835 taxa (14,714 for M, 13,748 for N, 14,254 for R, 14,054 for L, 14,496 for T). Relating the obtained values for temperature niche position to the bioclimatic data of species yielded a higher correlation than any of the original EIV systems (r = 0.859). The database: The newly developed Ecological Indicator Values for Europe (EIVE) 1.0, together with all source systems, is available in a flexible, harmonised open access database. Conclusions: EIVE is the most comprehensive ecological indicator value system for European vascular plants to date. The uniform interval scales for niche position and niche width provide new possibilities for ecological and macroecological analyses of vegetation patterns. The developed workflow and documentation will facilitate the future release of updated and expanded versions of EIVE, which may for example include the addition of further taxonomic groups, additional niche dimensions, external validation or regionalisation
    corecore