Time-resolved fast-neutron imaging with a pulse-counting image intensifier

A new imaging method that combines high-efficiency fast-neutron detection with sub-ns time resolution is presented. This is achieved by exploiting the high neutron detection efficiency of a thick scintillator and the fast timing capability and flexibility of light-pulse detection with a dedicated image intensifier. The neutron converter is a plastic scintillator slab or, alternatively, a scintillating fibre screen. The scintillator is optically coupled to a pulse counting image intensifier which measures the 2-dimensional position coordinates and the Time-Of-Flight (TOF) of each detected neutron with an intrinsic time resolution of less than 1 ns. Large-area imaging devices with high count rate capability can be obtained by lateral segmentation of the optical readout channels

Cardiac hybrid imaging

Computed tomography coronary angiography (CTCA) and myocardial perfusion imaging techniques (single photon emission computed tomography, SPECT, or positron emission tomography, PET) are established non-invasive modalities for the diagnosis of coronary artery disease (CAD). Cardiac hybrid imaging consists of the combination (or ‘fusion') of both modalities and allows obtaining complementary morphological (coronary anatomy, stenoses) and functional (myocardial perfusion) information in a single setting. However, hybrid cardiac imaging has also generated controversy with regard to which patients should undergo such integrated examinations for clinical effectiveness and minimization of costs and radiation dose. The feasibility and clinical value of hybrid imaging has been documented in small cohort studies and selected series of patients. Hybrid imaging appears to offer superior diagnostic and prognostic information compared with stand-alone or side-by-side interpretation of data sets. Particularly in patients with multivessel disease, the hybrid approach allows identification of flow-limiting coronary lesions and thereby provides useful information for the planning of revascularization procedures. Furthermore, integration of the detailed anatomical information from CTCA with the high molecular sensitivity of SPECT and PET may be useful to evaluate targeted molecular and cellular abnormalities in the future. While currently still restricted to specialized cardiac centres, the ongoing efforts to reduce radiation exposure and the increasing clinical interest will further pave the way for an increasing use of cardiac hybrid imaging in clinical practic

Evaluation of the consistency of fiber reinforced cementitious composites

The rheological properties of fresh concrete, mortar or cement paste are among the most important parameters when cementitious building materials are placed. New material designs, like high or ultrahigh performance concretes, include the addition of a high volume of fibers to the fresh mix influencing its workability properties. However, the analysis of the rheological properties of fiber reinforced cementitious composites is difficult. Conventional methods mostly do not apply, especially when a high fiber content and relatively stiff mixtures are used. For this reason, a new method was developed to evaluate the workability of fiber reinforced composites. This method was applied to carbon and PVA fiber reinforced high performance composites and was used to optimize the rheological properties of these composites for an application in a centrifugation casting proces

Der Wandel des Benutzerverhaltens in Zeiten des Internet

Im Rahmen eines Projektseminars am Institut für Bibliotheks- und Informationswissenschaft der Humboldt Universität zu Berlin wurden an wissenschaftlichen Bibliotheken Benutzerbefragungen durchgeführt. Wir haben die Antworten auf eine Frage zum Informationsverhalten bibliotheksübergreifend statistisch ausgewertet. Neben Unterschieden zwischen Fächern stellen wir fest, dass sich das Informationsverhalten junger Bibliotheksnutzer oft erheblich von dem älterer Nutzer unterscheidet. Das Verhalten von Bibliotheksnutzern hinsichtlich der Häufigkeit der Nutzung von Bibliotheksangeboten und dem World Wide Web (WWW) ist vorwiegend ähnlich. Nutzer mit konträrem Verhalten sind unterrepräsentiert gegenüber denen, die beides, Bibliothek und Web, oft oder beides wenig nutzen

An Optimization And Decision Support Tool For Long-Term Strategies In The Transformation Of Urban Water Infrastructure

Predicted climatic, demographic and socio-economic developments cause major adaptions of urban water infrastructures. The central water supply and wastewater systems in Europe do not meet the increased requirements of resource efficiency and sustainability anymore. Especially in rural areas predicted demographic change and the particular differentiated settlement structure affect the functionality of present water infrastructures. These new challenges require extensive and flexible adaptions or even a long-term and dynamic system change of urban infrastructures. These long-term transformations of infrastructure systems require the design of innovative strategies. In the project presented, environmental engineers together with city planners, mathematicians and computer scientists develop an innovative software-supported optimization and decision support system for the implementation of long-term transformations of existing infrastructures of water supply, wastewater and energy. Special attention is paid to the increasing uncertainty of future factors. Boundary conditions of transformation processes in rural areas as well as the connected political, economic and legal requirements are implied. The planning and decision scope of a cross-sectoral system transformation is focused on the local level under consideration of predicted future regional requirements and the engineering consideration of the supply and disposal system. The optimal solution for adaptation and transformation of systems regarding different objective functions will calculated for selected pilot studies and scenarios. The developed demonstrator of the decision model will be a prototype software solution for interactive process modeling and decision supporting. It will be tested and evaluated in a rural case study region in the Southwest of Germany. The selected municipalities have a wide range of settlement structures and face different challenges for the future design of urban supply and disposal systems

trans-Bis(perchlorato-κO)tetra­kis(1H-pyrazole-κN 2)copper(II)

The title compound, [Cu(ClO4)2(C3H4N2)4], was obtained unexpectedly by the reaction of copper(II) perchlorate hexa­hydrate with equimolar amounts of 1-chloro-1-nitro-2,2,2-tripyrazolylethane in methanol solution. The crystal structure comprises octa­hedrally coordinated Cu2+ ions, located on an inversion centre, with four pyrazole ligands in the equatorial plane. The average Cu—N distance is 2.000 (1) Å. Two perchlorate ions are coordinated to copper in trans positions [Cu—O = 2.4163 (11) Å]