Showing papers by "Mobil published in 2016"

Human impacts and aridity differentially alter soil N availability in drylands worldwide

Abstract: Aims Climate and human impacts are changing the nitrogen (N) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We conducted a global observational study to evaluate how aridity and human impacts, together with biotic and abiotic factors, affect key soil variables of the N cycle. Location Two hundred and twenty-four dryland sites from all continents except Antarctica widely differing in their environmental conditions and human influence. Methods Using a standardized field survey, we measured aridity, human impacts (i.e. proxies of land uses and air pollution), key biophysical variables (i.e. soil pH and texture and total plant cover) and six important variables related to N cycling in soils: total N, organic N, ammonium, nitrate, dissolved organic:inorganic N and N mineralization rates. We used structural equation modelling to assess the direct and indirect effects of aridity, human impacts and key biophysical variables on the N cycle. Results Human impacts increased the concentration of total N, while aridity reduced it. The effects of aridity and human impacts on the N cycle were spatially disconnected, which may favour scarcity of N in the most arid areas and promote its accumulation in the least arid areas. Main conclusions We found that increasing aridity and anthropogenic pressure are spatially disconnected in drylands. This implies that while places with low aridity and high human impact accumulate N, most arid sites with the lowest human impacts lose N. Our analyses also provide evidence that both increasing aridity and human impacts may enhance the relative dominance of inorganic N in dryland soils, having a negative impact on key functions and services provided by these ecosystems.

Traffic flow at a freeway work zone with reversible median lane

Abstract: Work zones on freeways usually affect the quality of service for road users. Aiming to reduce traffic flow disruptions to a minimum, Hessen Mobil - Road and Traffic Management installed an innovative reversible lane system in a work zone on Autobahn A 3 south-east of Frankfurt, Germany. The section with three lanes and temporary hard shoulder running in both directions carries a high amount of commuter traffic with considerable fluctuations in peak traffic flow direction. During road works, four lanes in the peak direction and three lanes in the non-peak direction could be maintained through the use of a reversible lane system. The paper discusses the effects of the reversible lane system on traffic flow and road safety. Radar measurements revealed a maximum traffic volume of roughly 1500 veh/h on the reversible lane, which is around 25% of the total traffic volume during peak hours. The capacity of the work zone was estimated with the stochastic capacity estimation technique based on models for censored data. Compared with the capacity of the unaffected three-lane carriageway with temporary hard shoulder running, a decrease of the capacity by 14% to 17% was estimated for the four-lane work zone configuration including the reversible lane, depending on the direction. The difference between the capacities in both directions can be explained by the different lane geometries at the respective beginning of the work zone, leading to a higher number of lane changing manoeuvers directly upstream of the lane diverge in one direction. The traffic flow analysis also yielded a considerable impact of the work zone on peak hour traffic demand volumes, which were reduced by approximately 1000 veh/h. Similar to other freeway work zones, the road safety analysis revealed an increase of accident rates during road works. However, based on police accident reports only 10% of the total number of accidents and none of the severe accidents could be linked to particular features of the reversible lane system. Altogether, the investigation shows that a reversible lane system is a useful, safe and accepted instrument of intelligent traffic management for freeway work zones with high fluctuations in peak traffic flow direction. At the analyzed work zone, estimated travel time losses of 400000 veh*h could be saved during two months of road works by the application of the reversible lane compared with a permanent lane reduction in one direction. Language: en

Vehicle Development for Natural Gas and Renewable Methane

Abstract: Natural gas vehicles are a mature technology already available today for solving the environmental problems caused by the automobile. The advantage is based on the features of the main fuel content methane. While keeping a minimum fuel quality standard, it is doesn’t matter to the vehicle technology whether the Methane is several million years old or just a few days. There is complete compatibility between fossil and renewable sources for this most simple of all hydrocarbons. Its highest possible ratio between hydrogen and carbon and the resulting features considering production/availability (fossil & renewable), the justifiable effort in the fuel system and the engine and environmental features make methane an ideal vehicle fuel.

Zur Entwicklungsgeschichte des Stahlverbundbaus

Abstract: Uber die historische Entwicklung des Fugens biegesteifer Bauteile der Werkstoffe Stahl und Beton – des Stahlverbundbaus – ist bisher wenig bekannt. Im vorliegenden Aufsatz werden deshalb die einzelnen Phasen so herausgearbeitet, dass die Entwicklungsgeschichte des Stahlverbundbaus in grosen Zugen erkennbar wird. Die Initialphase (1850–1900) bildet den Verbundtrager im Sinne von Empergers Ideal vom Haftverbund der Werkstoffpartner aus. Sukzessive folgt die konstruktive Trennung der Querschnittsteile in der Konstituierungsphase (1900–1925). In der Etablierungsphase (1925–1945) wachst die Erkenntnis, die Querschnittsteile konstruktiv verbinden zu mussen, zunachst als Lage- und dann als mechanische Schubsicherung. Dabei steht der Versuch im Mittelpunkt des Erkenntnisgewinns. Das quantifizierte Verbinden der Querschnittsteile durch ein konsolidiertes Versuchswesen und die Theoriebildung in der Vollendungsphase (1945–1981) lasst eine vielfaltig gebaute Wirklichkeit im Industrie- und Stahlverbundbruckenbau entstehen. On the evolution of steel-concrete composite construction. Little has been written so far about the historical development of the joining of rigid elements made from steel and concrete – steel-concrete composite construction. This article therefore describes the individual phases in such a way that the reader gains an overview of the evolution of composite construction with steel and concrete. The composite beam in the sense of Emperger's ideal of the friction/adhesion bond between the materials marked the initial phase (1850–1900). This was followed by the constitution phase (1900–1925) with its constructional separation of the elements of the cross-section. During the establishment phase (1925–1945) it was gradually realized that the elements of the cross-section had to be connected structurally, initially as positional restraint, later as mechanical shear connector. Tests verifies the bearing capacity of steel composite constructions. The quantified connection of the elements of the cross-section through standardized testing and the formation of theories in the classical phase (1945–1981) enabled the realization of multiple forms of steel-concrete composite construction for industrial buildings and bridges.

Horn-shaped decanter

Abstract: The decanter according to the invention for wines which comprises a receiving space (5) for the wine has a spout (4) that is connected thereto. The decanter has the shape of a horn with an approximately tangentially protruding leadpipe (2), wherein the spout (4) is the bell section. The bell section (4) is formed without bell. It is essential that the decanter according to the invention can be used as a music instrument, wherein the spout (4) serves as the bell section of the horn. It is possible with the decanter according to the invention, as a natural horn, to generate the tones of the natural tones series.

Messtechnische Überwachung extern vorgespannter Betonbrücken

Abstract: Die Instandsetzung von bestehenden Massivbrucken durch externe Vorspannung stellt eine verbreitete Masnahme der Tragwerksertuchtigung dar, da so Defizite in der Tragfahigkeit, Gebrauchstauglichkeit und Dauerhaftigkeit von Bauwerken kompensiert und eine Verlangerung der Nutzungsdauer erreicht werden konnen. Ein wichtiges Detail solcher Verstarkungsmasnahmen ist die Endverankerung der externen Spannglieder, da hier beachtliche Krafte in das Bauwerk eingeleitet werden. An drei mit externer Vorspannung verstarkten Talbrucken in Hessen wurde ein Monitoring installiert. Es wurden Wegaufnehmer in Langs- und Querrichtung der Brucke an die Verankerungsblocke und Dehnungsmessstreifen an die Querspannstabe installiert, um die Kraftubertragung zu uberwachen. Zusatzlich wurde die Luft- und Bauwerkstemperatur aufgezeichnet. Uber den Beobachtungszeitraum von mehr als drei Jahren konnten sowohl die Auswirkungen der Verstarkung erfasst als auch der Effekt der kurz- und langzeitigen Temperaturschwankungen beobachtet werden. Auch die Spannkraftverluste der Spannstabe wurden verfolgt. Die Messergebnisse wurden kontinuierlich ausgewertet und bei Uberschreitung definierter Grenzbedingungen wurde eine automatisierte Warnung ausgelost. Bei einem der Bauwerke konnte zudem die Uberfahrt von Schwertransporten mithilfe der Monitoringeinrichtung uberwacht werden. Insgesamt lieferten die Messungen wertvolle Hinweise zum Tragverhalten sowie zur Interaktion zwischen Verstarkung und Bestandsbauwerk.

Indoor- und Outdoor-Navigation in Smart Mobility-Szenarien

Abstract: Die Bereitstellung einer durchgangigen Indoor-/Outdoor-Navigation unterliegt auch heute nach wie vor umfangreichen technischen Anforderungen. Eine hohe Daten-Aktualitat, eine zuverlassige Indoor-Ortung und eine intuitive Bedienung sind Voraussetzung fur die Akzeptanz bei den Nutzern. Im Wettstreit der Anbieter urbaner Mobilitat wird die Bereitstellung einer durchgangigen Indoor-/Outdoor-Navigation zukunftig ein wesentlicher Baustein fur die Akzeptanz eines Verkehrsmittelanbieters und den Erfolg von Smart Mobility-Szenarien sein.

Die neue Lahntalbrücke Limburg im Zuge der BAB 3 – Wettbewerb und Entwurf

Abstract: An der Lahntalbrucke Limburg wird das Bemuhen der planenden Ingenieure/innen und Architekten/innen deutlich, immer dann, wenn ein Neubau erforderlich wird, fur das reprasenta tive Tal eine gelungen gestaltete Bruckenkonstruktion auszu arbeiten. Bei beiden Ersatzneubauten, auch notig, um dem stetig steigenden Verkehrsaufkommen gerecht zu werden, haben sich im Wettbewerb Spannbetonkonstruktionen durchgesetzt, die optisch im Wesentlichen durch ihre Schlichtheit uberzeugen und dem Dom seine gestalterische Prasenz im Tal belassen.