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Many polysaccharides with varying shear stability have been grafted with polyacrylamide branches to enhance their turbulent drag‐reducing and flocculating characteristics. Their aqueous solutions have been studied by shear and extensional rheometric techniques. All the solutions of grafted carboxymethyl cellulose, guar gum, starch, and sodium alginate exhibit shear‐thinning non‐Newtonian behavior. The viscosities are higher than those of ungrafted polysaccharides. The solutions of grafted carboxymethyl cellulose, guar gum and sodium alginate are spinnable. When subjected to uniaxial stretching in a stretching device, the formation of a thread and reduction of the thread diameter with time were observed. The stretching device was used to measure the relaxation time, which was found to be the largest (∼26 ms), on the order of flexible polyacrylamide, for the grafted carboxymethyl cellulose. Though a polyacrylamide solution degrades through nozzle flow and completely loses its extensional properties, a solution of grafted carboxymethyl cellulose retains about half its relaxation time because of the shear stability of polysaccharide chains and their structure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3200–3209, 2000

ABSTRACT:Various polysaccharides, such as starch and its constituent amylopectin, are used as flocculants in industrial effluent treatment. Grafting them with polyacrylamide branches enhances their flocculating and turbulent drag-reducing characteristics drastically. Aqueous solutions of the graft copolymer of amylopectin with polyacrylamide show a shear thinning non-Newtonian behavior. It is also expected that the solutions exhibit extensional effects. When the aqueous solution at 1000 ppm was subjected to a stretching device, the formation of a thread and reduction of the thread diameter with time were observed. The extensional relaxation time was thus estimated and compared with that of polyacrylamide. The measured relaxation time indicates that the performance of the rigid branched amylopectin, when grafted with fewer and longer polyacrylamide branches, is overwhelmed by the grafted polyacrylamide chains and the reduction of rigidity by the grafting process itself. This article reports the details of the investigations that led to these conclusions.

Mainly in the context of global climate change the awareness of landslide hazards has risen considerably in most mountainous regions worldwide in the last years. National and regional hazard mapping programs were set up in many countries and most of the potentially endangered sites have been identified. Although exclusive geodetic and geotechnical instrumentation is available today, due to some economical reasons only few of the identified potentially risky landslides are monitored permanently. The intention of the alpEWAS research project is to develop and to test new techniques suitable for e‰cient and cost-e¤ective landslide monitoring. These techniques are combined in a geo sensor network with an enclosed geo data base and a developed software package to use the whole system for stakeholder information and early warning purposes. The core of the project is the development and testing of the three innovative measurement systems time domain reflectometry (TDR) for the detection of subsurface displacements in boreholes and reflectorless video tacheometry (VTPS) and a low cost GNSS sensor component for the determination of 3D surface movements. Essential experiences obtained during the project will be described.

Modern electronic tacheometers offer the possibility to capture kinematic processes in real time. In case when the kinematic process is observed with only one measurement system, we have no possibility to perform redundant observations that would enable the accuracy estimation of observations and computed values. The Kalman filter represents a method of advanced geodetic analysis and as such adjusts the redundant data in an optimum way. Incorporating a time component directly into a processing of terrestrial kinematic observations demands good knowledge about the procedure of processing kinematic terrestrial observations and the electronic tacheometer capabilities. For this purpose the developed model of Kalman filter for processing kinematic terrestrial observations-discrete Wiener process acceleration model-was tested on reference trajectory in the Geodetic Laboratory of the Technical University Munich.

Engine 3E is the aero engine part of the German Aeronautics Research Program under which Rolls-Royce Deutschland developed key technologies for an all new core engine that incorporates major advances with regard to environmental friendliness, efficiency and economy. The derived E3E core engine will serve as a scalable baseline for the future two-shaft engine family in the medium take-off thrust range between 12 – 40 klb. The core consists of a highly loaded 9-stage HPC, a lean burn combustion chamber with internal fuel staging and a 2-stage shroudless HPT. On the basis of its high specific power, low NOx combustion and low manufacturing cost, it will enable significant improvements in SFC, emissions, unit cost and weight. The related technology demonstrator is currently in the final build and instrumentation phase for testing in an altitude test facility in first quarter 2008.

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