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101.
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Die Old White Nile und die Old Blue Nile Bridge waren die ersten beiden Brücken überhaupt, die in Khartoum, der Hauptstadt des Sudan über den Nil führten. Sie wurden von der Britischen Baufirma Dorman Long Ltd. in den Jahren 1908 und 1928 gebaut und erfüllen bis heute in nahezu unveränderter Form ihren Dienst. Sie stellen damit funktionstüchtige, ingenieurtechnische Denkmale dar und zeugen von der außergewöhnlichen Ingenieurleistung, die hier unter schwierigen klimatischen und technologischen Bedingung erbracht wurde. Der folgende Beitrag befasst sich mit der Instandsetzung der Old White Nile Bridge, welche im Zeitraum von 2004 bis 2007 durchgeführt wurde. Die Schüßler‐Plan Ingenieurgesellschaft wurde von der Brückenbauverwaltung der Stadt Khartoum mit verschiedenen Untersuchungen im Zusammenhang mit dem Sanierungskonzept betraut. Der Aufsatz befasst sich neben einem historischen Rückblick mit der Entscheidung, ob ein Auswechseln der 80 Jahre alten, in ihrer Funktion stark eingeschränkten Brückenlager aus statischer Sicht notwendig ist oder diese am Bauwerk belassen werden können. Auch für die Old Blue Nile Bridge ist in den kommenden Jahren eine grundlegende Instandsetzung vorgesehen. Da die Konstruktion vergleichbar ist, können die bei der Old White Nile Bridge gewonnenen Erkenntnisse hierbei einen wertvollen Beitrag leisten. Rehabilitation of old steel bridges over the Nile in Khartoum/Sudan. The Old White Nile Bridge and the Old Blue Nile Bridge were the first bridges ever to cross the Nile at Khartoum – Capital of the Sudan. They were build In 1928 and 1908 by the British Company Dorman Long Ltd. and till today service the traffic in Khartoum in their since then unchanged form. They represent as such a functional technical monument and an attest of the unusual engineering achievement, which was realised under the most extreme climatic and technological conditions. The following report is about the rehabilitation of the Old White Nile Bridge, which was carried out from 2004 till 2007. The Schüßler‐Plan Ingenieurgesellschaft was contracted by the Bridge Department of the State of Khartoum with several analysis related with the rehabilitation concept. The report starts with an historic review of the bridge and continuous with the decision weather it is statically necessary to exchange the nearly 80 year old bearings that are strongly hindered in their function, or weather they could be left unchanged. For the Blue Nile Bridge also, a complete rehabilitation is planned in the near future. Since the two bridge structures are comparable, the knowledge collected at the Old White Nile Bridge could be of great advantage for the Blue Nile rehabilitation. 相似文献
104.
S. Chartier B. Schleicher T. Feger T. Purtova G. Fischer H. Schumacher 《Analog Integrated Circuits and Signal Processing》2008,55(1):77-83
In this work, a fully integrated, fully differential amplifier operating at 79 GHz using a high-speed Si/SiGe heterojunction
bipolar technology is presented. This integrated circuit needs a single supply voltage and shows high performance such as
high gain, excellent reverse isolation and low power consumption (90 mW at 3 V supply voltage). This result was achieved by
using three cascaded cascode amplifiers as well as thin-film microstrip lines and MIM capacitors as reactive elements. In
addition, the frequency of operation can be easily adjusted within a wide range by changing the length of the matching network
(by using a focused ion beam or an ultrasonic manipulator). Because the measurement of differential ICs operating in the millimeter-wave
domain is complex, a simple but efficient layout modification was utilized to easily measure single-ended the differential
integrated circuit, also at these high frequencies. 相似文献
105.
Quan-Bao Ma Jürgen Ziegler Bernhard Kaiser Dominic Fertig Wolfram Calvet Eswaran Murugasen Wolfram Jaegermann 《International Journal of Hydrogen Energy》2014
The electrochemical properties of single-crystalline p-type 3C-SiC films on p-Si substrate were investigated as an electrode in H2SO4 aqueous solutions in dark and under white light illumination. The photoelectrochemical (PEC) measurements indicates the p-type 3C-SiC film on p-Si substrate can generate a cathodic photocurrent as a photocathode, which corresponds to hydrogen production, and generate an anodic photocurrent as a photoanode, which corresponds to oxygen evolution. The surface chemical states of the films were investigated by XPS. In order to observe the surface chemical state changes after PEC test, the range of applied potential to the electrode was divided into three zones: −3.6 to 0 V, 0–1.5 V and 1.5–4 V vs. Ag/AgCl. After separated PEC tests in these three areas, XPS shows the surface of the SiC film in the range of −3.6 to 0 V and 0–1.5 V was stable without oxidation except the band bending occurred. But in the range of 1.5–4 V the film surface was oxidized due to anodic oxidation. 相似文献
106.
Investigations concerning the behaviour and load-bearing capacity of built-up light-gauge structures
A V-shaped roof system for spans between 15 and 30 m is presented. The research project has two different purposes—the first is to demonstrate new possibilities for the use of thin-walled structural elements and to prove the efficiency and the competitive position of such structures, and the second is to study different problems concerning the behaviour and load-bearing capacity of structural elements built up by profiled sheeting and thin-walled sections.Some test results concerning the diaphragm action of the webs and the load-bearing capacity of the elastically restrained flange sections are revised. 相似文献
107.
In the current study the savings of CO2 emissions due to the use of ground source heat pump (GSHP) systems was investigated in comparison to conventional heating systems. Based on a subsidy program for GSHP systems in southwest Germany, the regional, average, and total CO2 savings of 1105 installed GSHP systems were determined on a regional scale. The emitted CO2 per kWh of heating demand for the studied scenario resulted in 149 g CO2/kWh for GSHP using the German electricity mix and 65 g CO2/kWh using the regional electricity mix, which results in CO2 savings of 35% or 72%, respectively. Similar CO2 avoidances of GSHP systems were found in American and European studies ranging between 15% and 77% strongly depending on the supplied energy for the heat pumps and the efficiency of installation. The resulting CO2 savings for one installed GSHP unit in the present study therefore range between 1800 and 4000 kg per year. Nevertheless, the minimum average total annual CO2 savings of all installed GSHP systems due to the subsidy program amounted to 2000 tons per year. The maximum regional avoided additional CO2 emissions are primarily associated with the affluent suburbs of the most densely populated area in the region. In 2006 the total contribution of CO2 savings due to GSHP systems in Germany was only about 3.4% of the total renewable energies. However, continuously rising numbers of installed GSHP units and the increasing use of renewable electricity demonstrate that there is a fine opportunity to substantially avoid additional CO2 emissions associated with the provision of heating (and cooling) of buildings and other facilities. 相似文献
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109.
The interaction kinetics of the Am(III) ion with aquatic humic colloids is investigated under near-natural conditions by column experiments with a sandy aquifer sample rich in humic substancesforthe appraisal of the migration behavior of Am. The association and dissociation kinetics of the Am ion onto and from humic colloids control the migration of colloid-borne Am. As the contact time between Am and humic colloids prior to introduction into a column is increased, the mobility of colloid-borne Am is enhanced and hence the recovery of Am in the effluent increases. On the other hand, an increase of the migration time and residence time in column, respectively, reduces the Am recovery. Considering these experimental results a refined version of the kinetic model KICAM (Kinetically Controlled Availability Model), which suggests different Am binding modes with humic colloids, was developed. Applying KICAM it is possible to predict static and dynamic experiments affected by the kinetically controlled Am/humic colloid interactions over the range of 1 h up to several months. However, to apply these experimental results to long-term conditions, the Am binding scheme as proposed in KICAM needs to be verified. This paper provides, therefore, a basis for a better understanding of the colloid-borne Am migration in porous aquifer systems. 相似文献
110.