Sample records for risoes nukleare anlaeg

  1. Terror mit Atomwaffen: reale Gefahr? Nukleare und Radiologische Waffen

    NASA Astrophysics Data System (ADS)

    Harigel, Gert G.


    Können Terroristen sich nukleare Massenvernichtungswaffen beschaffen? Dazu müssten sie ausreichende Mengen an waffenfähigem, spaltbarem Material stehlen. Selbst der Bau einer primitiven Atombombe erfordert einen hohen technischen Aufwand und Spezialisten. Wahrscheinlicher ist deshalb der Diebstahl einer kleinen taktischen Kernwaffe. Alternativ könnten Terroristen sich radioaktives Material aus zivilen Quellen beschaffen und daraus eine Schmutzige Bombe bauen. Eine solche radiologische Waffe wäre keine echte Massenvernichtungswaffe, doch ihre psychologische Wirkung könnte stark sein. Das macht sie für Terroristen attraktiv, weswegen diese Gefahr ernst genommen werden muss.

  2. RISO: A New Online Tool for Bringing the Sun into the Classroom

    NASA Astrophysics Data System (ADS)

    Johnson, Michael; Hood, J.; Cruzen, S. T.; Williams, R. N. M.


    The Real-Time Interactive Solar Observatory (RISO) is an online portal that allows schools worldwide to log in via the internet and control the telescopes at Columbus State University's Mead Observatory. Users of RISO are able to view live video of the Sun, image the Sun, and complete activities while observing the Sun, all from their own classroom. Debuted in 2007, RISO will begin its full observing schedule in January 2008. In this oral presentation, we will highlight the features of RISO and will discuss the current activities users can complete with RISO. We will also discuss the future activities, such as a cloudy day simulator and field of view calculations that are currently in development. Support for RISO has been provided by NASA through the Georgia Space Science Grant Consortium.

  3. TL emission spectra measurements using a spectrometer coupled to the Risoe TL/OSL reader

    NASA Astrophysics Data System (ADS)

    Yoshizumi, Maíra T.; Caldas, Linda V. E.


    A high sensitivity spectrometer (Ocean Optics QE65 Pro) was coupled to the Risoe TL/OSL reader to measure TL emission spectra of four different dosimeters. This spectrometer is based on a Hamamatsu FFT-CCD detector with a 2-D arrangement of pixels (1044×64), which detects luminescence in a range of 200-950 nm. An optical fiber was used to guide the signal from the sample to the spectrometer. TL spectra from LiF, CaSO4:Dy, BeO and Al2O3:C detectors were obtained and they are presented in this work. The proposed detection system showed good response; spectra shape, in accordance with the literature, were obtained, validating the system.


    SciTech Connect

    Edwards, Danny J.; Singh, Bachu N.


    PNNL and Riso have been collaborating since 1994 on a series of irradiation experiments on pure copper and various alloys of interest to the fusion materials community. The collaboration has been of great benefit to both institutes by sharing resources and experience. Past research has concentrated on examining the microstructural evolution during neutron irradiation and the influence this microstructural change exerts on the deformation response. Post-irradiation annealing experiments of both irradiated pure copper and CuCrZr yielded unique insights into the relationship between the microstructure and the deformation response. The results of that experiment also raised further questions regarding the stability and structure of the small defects produced during irradiation, particularly regarding the stability of these defects during annealing and how they interact with mobile dislocations. The focus of ongoing work has now shifted to examining the issues of defect stability in irradiated materials, dislocation generation from stress concentrations at interfaces in irradiated materials, and a new experiment on in-situ straining during irradiation and how this affects microstructural evolution and the relationship to mechanical properties.

  5. Die nuklearen Anlagen von Hanford (1943-1987) Eine Fallstudie über die Schnittstellen von Physik, Biologie und die US-amerikanische Gesellschaft zur Zeit des Kalten Krieges

    NASA Astrophysics Data System (ADS)

    Macuglia, Daniele

    Die Geschichte des Kalten Krieges eröffnet viele Möglichkeiten, sich näher mit den Schnittstellen von Physik und Biologie während des 20. Jahrhunderts zu befassen. Nicht nur das Unglück in Tschernobyl aus dem Jahr 1986, auch das Beispiel der nuklearen Anlagen in Hanford in den Vereinigten Staaten zeigt die biologischen Folgen von nuklearer Physik.

  6. Early User Experience with BISON Fuel Performance Code

    SciTech Connect

    D. M. Perez


    Three Fuel Modeling Exercise II (FUMEX II) LWR fuel irradiation experiments were simulated and analyzed using the fuel performance code BISON to demonstrate code utility for modeling of the LWR fuel performance. Comparisons were made against the BISON results and the experimental data for the three assessment cases. The assessment cases reported within this report include IFA-597.3 Rod 8, Riso AN3 and Riso AN4.

  7. PV Systems Reliability Final Technical Report: Ground Fault Detection

    SciTech Connect

    Lavrova, Olga; Flicker, Jack David; Johnson, Jay


    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  8. Collaborative Information Retrieval.

    ERIC Educational Resources Information Center

    Bruce, Harry; Fidel, Raya


    Researchers from the University of Washington, Microsoft Research, Boeing, and Risoe National Laboratory in Denmark have embarked on a project to explore the manifestations of Collaborative Information Retrieval (CIR) in work settings and to propose technological innovations and organizational changes that can support, facilitate, and improve CIR.…

  9. Reduced enrichment for research and test reactors: Proceedings

    SciTech Connect

    Not Available


    The 15th annual Reduced Enrichment for Research and Test Reactors (RERTR) international meeting was organized by Ris{o} National Laboratory in cooperation with the International Atomic Energy Agency and Argonne National Laboratory. The topics of the meeting were the following: National Programs, Fuel Fabrication, Licensing Aspects, States of Conversion, Fuel Testing, and Fuel Cycle. Individual papers have been cataloged separately.

  10. A model to predict the power output from wind farms

    SciTech Connect

    Landberg, L.


    This paper will describe a model that can predict the power output from wind farms. To give examples of input the model is applied to a wind farm in Texas. The predictions are generated from forecasts from the NGM model of NCEP. These predictions are made valid at individual sites (wind farms) by applying a matrix calculated by the sub-models of WASP (Wind Atlas Application and Analysis Program). The actual wind farm production is calculated using the Riso PARK model. Because of the preliminary nature of the results, they will not be given. However, similar results from Europe will be given.

  11. Castor-1C spent fuel storage cask decay heat, heat transfer, and shielding analyses

    SciTech Connect

    Rector, D.R.; McCann, R.A.; Jenquin, U.P.; Heeb, C.M.; Creer, J.M.; Wheeler, C.L.


    This report documents the decay heat, heat transfer, and shielding analyses of the Gesellschaft fuer Nuklear Services (GNS) CASTOR-1C cask used in a spent fuel storage demonstration performed at Preussen Elektra's Wurgassen nuclear power plant. The demonstration was performed between March 1982 and January 1984, and resulted in cask and fuel temperature data and cask exterior surface gamma-ray and neutron radiation dose rate measurements. The purpose of the analyses reported here was to evaluate decay heat, heat transfer, and shielding computer codes. The analyses consisted of (1) performing pre-look predictions (predictions performed before the analysts were provided the test data), (2) comparing ORIGEN2 (decay heat), COBRA-SFS and HYDRA (heat transfer), and QAD and DOT (shielding) results to data, and (3) performing post-test analyses if appropriate. Even though two heat transfer codes were used to predict CASTOR-1C cask test data, no attempt was made to compare the two codes. The codes are being evaluated with other test data (single-assembly data and other cask data), and to compare the codes based on one set of data may be premature and lead to erroneous conclusions.

  12. Swedish-German actinide migration experiment at ASPO hard rock laboratory.


    Kienzler, B; Vejmelka, P; Römer, J; Fanghänel, E; Jansson, M; Eriksen, T E; Wikberg, P


    Within the scope of a bilateral cooperation between Svensk Kärnbränslehantering (SKB) and Forschungszentrum Karlsruhe, Institut für Nukleare Entsorgung (FZK-INE), an actinide migration experiment is currently being performed at the Aspö Hard Rock Laboratory (HRL) in Sweden. This paper covers laboratory and in situ investigations on actinide migration in single-fractured granite core samples. For the in situ experiment, the CHEMLAB 2 probe developed by SKB was used. The experimental setup as well as the breakthrough of inert tracers and of the actinides Am, Np and Pu are presented. The breakthrough curves of inert tracers were analyzed to determine hydraulic properties of the fractured samples. Postmortem analyses of the solid samples were performed to characterize the flow path and the sorbed actinides. After cutting the cores, the abraded material was analyzed with respect to sorbed actinides. The slices were scanned optically to visualize the flow path. Effective volumes and inner surface areas were measured. In the experiments, only breakthrough of Np(V) was observed. In each experiment, the recovery of Np(V) was < or = 40%. Breakthrough of Am(III) and Pu(IV) as well as of Np(IV) was not observed.

  13. Upgrading of data acquisition software for centralized radiation monitoring system in Malaysian Nuclear Agency

    NASA Astrophysics Data System (ADS)

    Yussup, F.; Ibrahim, M. M.; Haris, M. F.; Soh, S. C.; Hasim, H.; Azman, A.; Razalim, F. A. A.; Yapp, R.; Ramli, A. A. M.


    With the growth of technology, many devices and equipments can be connected to the network and internet to enable online data acquisition for real-time data monitoring and control from monitoring devices located at remote sites. Centralized radiation monitoring system (CRMS) is a system that enables area radiation level at various locations in Malaysian Nuclear Agency (Nuklear Malaysia) to be monitored centrally by using a web browser. The Local Area Network (LAN) in Nuclear Malaysia is utilized in CRMS as a communication media for data acquisition of the area radiation levels from radiation detectors. The development of the system involves device configuration, wiring, network and hardware installation, software and web development. This paper describes the software upgrading on the system server that is responsible to acquire and record the area radiation readings from the detectors. The recorded readings are called in a web programming to be displayed on a website. Besides the main feature which is acquiring the area radiation levels in Nuclear Malaysia centrally, the upgrading involves new features such as uniform time interval for data recording and exporting, warning system and dose triggering.

  14. Application of the BISON Fuel Performance Code to the FUMEX-III Coordinated Research Project

    SciTech Connect

    R. L. Williamson; S. R. Novascone


    INL recently participated in FUMEX-III, an International Atomic Energy Agency sponsored fuel modeling Coordinated Research Project. A main purpose of FUMEX-III is to compare code predictions to reliable experimental data. During the same time period, the INL initiated development of a new multidimensional (2D and 3D) multiphysics nuclear fuel performance code called BISON. Interactions with international fuel modeling researchers via FUMEX-III played a significant and important role in the BISON evolution, particularly influencing the selection of material and behavioral models which are now included in the code. BISON's ability to model integral fuel rod behavior did not mature until 2011, thus the only FUMEX-III case considered was the Riso3-GE7 experiment, which includes measurements of rod outer diameter following pellet clad mechanical interaction (PCMI) resulting from a power ramp late in fuel life. BISON comparisons to the Riso3-GE7 final rod diameter measurements are quite reasonable. The INL is very interested in participation in the next Fuel Modeling Coordinated Research Project and would like to see the project initiated as soon as possible.

  15. Protection of Operators and Environment - the Safety Concept of the Karlsruhe Vitrification Plant VEK

    SciTech Connect

    Fleisch, J.; Kuttruf, H.; Lumpp, W.; Pfeifer, W.; Roth, G.; Weisenburger, S.


    The Karlsruhe Vitrification Plant (VEK) plant is a milestone in decommissioning and complete dismantling of the former Karlsruhe Reprocessing Plant WAK, which is in an advanced stage of disassembly. The VEK is scheduled to vitrify approx. 70 m3 of the highly radioactive liquid waste (HLW) resulting from reprocessing. Site preparation, civil work and component manufacturing began in 1999. The building will be finalized by mid of 2002, hot vitrification operation is currently scheduled for 2004/2005. Provisions against damages arising from construction and operation of the VEK had to be made in accordance with the state of the art as laid down in the German Atomic Law and the Radiation Protection Regulations. For this purpose, the appropriate analysis of accidents and their external and internal impacts were investigated. During the detailed design phase, a failure effects analysis was carried out, in which single events were studied with respect to the objectives of protection and ensuring activity containment, limiting radioactive discharges to the environment and protecting of the staff. Parallel to the planning phase of the VEK plant a cold prototype test facility (PVA) covering the main process steps was constructed and operated at the Institut fuer Nukleare Entsorgung (INE) of FZK. This pilot operation served to demonstrate the process technique and its operation with a simulated waste solution, and to test the main items of equipment, but was conducted also to use the experimental data and experience to back the safety concept of the radioactive VEK plant. This paper describes the basis of the safety concept of the VEK plant and results of the failure effect analysis. The experimental simulation of the failure scenarios, their effect on the process behavior, and the controllability of these events as well as the effect of the results on the safety concept of VEK are discussed. Additionally, an overview of the actual status of civil work and manufacturing of

  16. Dry Cask Storage Characterization Project - Phase 1: CASTOR V/21 Cask Opening and Examination

    SciTech Connect

    Bare, Walter Claude; Ebner, Matthias Anthony; Torgerson, Laurence Dale


    This report documents visual examination and testing conducted in 1999 and early 2000 at the Idaho National Engineering and Environmental Laboratory (INEEL) on a Gesellschaft für Nuklear Service (GNS) CASTOR V/21 pressurized water reactor (PWR) spent fuel dry storage cask. The purpose of the examination and testing is to develop a technical basis for renewal of licenses and Certificates of Compliance for dry storage systems for spent nuclear fuel and high-level waste at independent spent fuel storage installation sites. The examination and testing was conducted to assess the condition of the cask internal and external surfaces, cask contents consisting of 21 Westinghouse PWR spent fuel assemblies from Dominion’s (formerly named Virginia Power) Surry Power Station and cask concrete storage pad. The assemblies have been continuously stored in the CASTOR cask since 1985. Cask exterior surface and selected fuel assembly temperatures, and cask surface gamma and neutron dose rates were measured. Cask external/internal surfaces, fuel basket components including accessible weldments, fuel assembly exteriors, and primary lid seals were visually examined. Selected fuel rods were removed from one fuel assembly, visually examined, and then shipped to Argonne National Laboratory for nondestructive, destructive, and mechanical examination. Cask interior crud samples and helium cover gas samples were collected and analyzed. The results of the examination and testing indicate the concrete storage pad, CASTOR V/21 cask, and cask contents exhibited sound structural and seal integrity and that long-term storage has not caused detectable degradation of the spent fuel cladding or the release of gaseous fission products between 1985 and 1999.

  17. Mandibular implant-supported overdentures: attachment systems, and number and locations of implants--Part I.


    Warreth, Abdulhadi; Alkadhimi, Aslam Fadel; Sultan, Ahmed; Byrne, Caroline; Woods, Edel


    The use of dental implants in replacing missing teeth is an integral part of restorative dental treatment. Use of conventional complete dentures is associated with several problems such as lack of denture stability, support and retention. However, when mandibular complete dentures were used with two or more implants, an improvement in the patients' psychological and social well-being could be seen. There is general consensus that removable implant-supported overdentures (RISOs) with two implants should be considered as the first-choice standard of care for an edentulous mandible. This treatment option necessitates the use of attachment systems that connect the complete denture to the implant. Nevertheless, each attachment system has its inherent advantages and disadvantages, which should be considered when choosing a system. The first part of this article provides an overview on options available to restore the mandibular edentulous arch with dental implants. Different types of attachment systems, their features and drawbacks are also reviewed.

  18. Testing of a direct drive generator for wind turbines

    SciTech Connect

    Sondergaard, L.M.


    The normal drive train of a wind turbine consists a gearbox and a 4 to 8 poles asynchronous generator. The gearbox is an expensive and unreliable components and this paper deals with testing of a direct drive synchronous generator for a gearless wind turbine. The Danish company Belt Electric has constructed and manufactured a 27 kW prototype radial flux PM-generator (DD600). They have used cheap hard ferrite magnets in the rotor of this PM-generator. This generator has been tested at Riso and the test results are investigated and analyzed in this paper. The tests have been done with three different load types (1: resistance; 2: diode rectifier, DC-capacitor, resistance; 3: AC-capacitor, diode rectifier, DC-capacitor, resistance). 1 ref., 9 figs., 5 tabs.

  19. Basis of human factors methodology applied in the Westinghouse AP600 design

    SciTech Connect

    Carrera, J.P.; Easter, J.R. )


    The incident at Three Mile Island Unit 2 brought about an awareness that there is a need for a new perspective on nuclear power plant operator performance. It was discerned that besides executing control actions, the operator needs an additional role, that of systems supervisor-someone who considers plant health at the functional level of how all the plant processes are related and how they perform with regard to the high-level operational goals of the plant. Westinghouse has taken the initiative to apply these ideas in dealing with the operator by studying the work of Rasmussen of Denmark's Riso Laboratory, regarding knowledge-based behavior and the requirements for supporting the cognitive processes required of an operator. This has led to the Westinghouse Man-Machine-Interface System (MMIS) design process.

  20. Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method.


    Leveque, Nathalie L; Acheampong, Akwasi; Heron, Sylvie; Tchapla, Alain


    The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG((AAB and/or ABA))](+) generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)](+) or the neutral TAG molecule (TAG((AAB and/or ABA))) leading to [ref, Li](+). The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (R(iso)), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures. PMID:22444537

  1. Rotor loading on a three-bladed wind turbine

    NASA Astrophysics Data System (ADS)

    Madsen, Peter Hauge; Rasmussen, Flemming

    For a well designed and adjusted horizontal axis wind turbine, the turbulence in the wind is one of the primary sources of cyclic loading. Wind turbulence not only causes blade loads, but is responsible for the major part of the cyclic rotor loads which are transferred through the rotor shaft. In order to predict the cyclic part of the primary structural rotor loads, the thrust, the yaw and the tilt moment, a model was developed. The model works in the frequency domain and uses the standard engineering representation of turbulence in terms of a coherence function and a power spectrum. The model which accounts for the rotational sampling of the turbulent wind field, shows good agreement with the results of testing programs on wind turbines which are tested at The Test Station for Windmills at Risoe National Laboratory. The comparison is made in terms of both the frequency content of the turbulence induced loads as well as the associated fatigue damage. A parametric study demonstrates the effect of the tower bending and tower torsion flexibility on the magnitude of the cyclic rotor loads.

  2. On application of low doses from beta radiation source in OSL retrospective dosimetry

    NASA Astrophysics Data System (ADS)

    Przegietka, K.; Chruscinska, A.


    The paper reports on three levels of dose rates obtainable from single beta source: (133±3) mGy/s, (17.8±0.3) mGy/s and (1.94±0.04) mGy/s, as calibrated for quartz sand grains. These values were achieved for different attenuation stages of beta radiation emitted by standard 90Sr/90Y source with the nominal activity of 1.48 GBq attached to an automatic luminescence reader. Lower dose rates give opportunity for exact dosing, which is especially required in luminescence dating applied to young samples as well as in environmental dosimetry. Moreover new method for determining time lag in opening the source in the Riso beta irradiator is presented. This allowed to resolve the contradiction appearing in the literature. The time delay was found to be (0.15±0.01) s per single irradiation. For improving accuracy the dose rate correction is suggest to be taken into account for irradiations shorter than 30 s.

  3. Measurement of ClO and CO2 for ACCENT

    NASA Technical Reports Server (NTRS)

    Toohey, Darin


    Observations have shown that ozone in largely removed in rocket plumes within an hour of launch [M.N. Ross, et al., Nature 390, 62-64, 1997]. Large abundances of chlorine oxide (ClO) were first detected in the fresh plume of a Delta rocket in May of 1998 from the NASA WB-57 during the Air Force RISO campaign by the CORE instrument developed at UC Irvine. Similar abundances were detected a month later in the plume of an ATLAS II rocket. Although the maximum ClO observed in these plumes was twenty-five times larger than the highest values ever observed in the perturbed polar vortices, in a new study, [M.N. Ross, et al., Geophys. Res. Lett., 2000, in press] could not account for observed ozone losses based on known chlorine photochemistry. New measurements were obtained in plumes of Delta, Atlas, and Athena rockets in 1999 during ACCENT with the CORE instrument augmented with a modified LiCor non-dispersed infrared detector for fast-response measurements of carbon-dioxide (CO2). The absolute abundance of this specie constrains the rocket emission stoichiometry, and its relative abundance serves as a tracer of dilution. The combination of ClO and CO2 will provide important new insights into the temporal and spatial evolution of reactive chlorine partitioning and its dependence on rocket motor type.

  4. Recent results on the neutron irradiation of ITER candidate copper alloys irradiated in DR-3 at 250{degrees}C to 0.3 dpa

    SciTech Connect

    Edwards, D.J.; Singh, B.N.; Toft, P.; Eldrup, M.


    Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime-ageing and bonding thermal treatment with additional specimens re-aged and given a reactor bakeout treatment at 350{degrees}C for 100 h. CuAl-25 was also heat treated to simulate the effects of a bonding thermal cycle on the material. A number of heat treated specimens were neutron irradiated at 250{degrees}C to a dose level of {approximately}0.3 dpa in the DR-3 reactor as Riso. The main effect of the bonding thermal cycle heat treatment was a slight decrease in strength of CuCrZr and CuNiBe alloys. The strength of CuAl-25, on the other hand, remained almost unaltered. The post irradiation tests at 250{degrees}C showed a severe loss of ductility in the case of the CuNiBe alloy. The irradiated CuAl-25 and CuCrZr specimens exhibited a reasonable amount of uniform elongation, with CuCrZr possessing a lower strength.

  5. Design, Synthesis, and Protein Crystallography of Biaryltriazoles as Potent Tautomerase Inhibitors of Macrophage Migration Inhibitory Factor

    PubMed Central

    Dziedzic, Pawel; Cisneros, José A.; Robertson, Michael J.; Hare, Alissa A.; Danford, Nadia E.; Baxter, Richard H. G.; Jorgensen, William L.


    Optimization is reported for biaryltriazoles as inhibitors of the tautomerase activity of human macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with numerous inflammatory diseases and cancer. A combined approach was taken featuring organic synthesis, enzymatic assaying, crystallography, and modeling including free-energy perturbation (FEP) calculations. X-ray crystal structures for 3a and 3b bound to MIF are reported and provided a basis for the modeling efforts. The accommodation of the inhibitors in the binding site is striking with multiple hydrogen bonds and aryl–aryl interactions. Additional modeling encouraged pursuit of 5-phenoxyquinolinyl analogues, which led to the very potent compound 3s. Activity was further enhanced by addition of a fluorine atom adjacent to the phenolic hydroxyl group as in 3w, 3z, 3aa, and 3bb to strengthen a key hydrogen bond. It is also shown that physical properties of the compounds can be modulated by variation of solvent-exposed substituents. Several of the compounds are likely the most potent known MIF tautomerase inhibitors; the most active ones are more than 1000-fold more active than the well-studied (R)-ISO-1 and more than 200-fold more active than the chromen-4-one Orita-13. PMID:25697265

  6. Processing and Characterization of New Materials at Pomona College with External Collaborations

    NASA Astrophysics Data System (ADS)

    Tanenbaum, David


    My research program focuses on the evolution of novel lithographic, growth, and characterization processes for use with thin films for microelectronics and photovoltaic technologies. We have established facilities at Pomona College for wet chemistry, spin coating, thermal evaporation,~micro-contact printing, ultra violet ozone cleaning, oxygen plasma cleaning, Au/Pd sputter coating, critical point drying, optical microscopy, optical lithography, ellipsometry, spectral reflectance, electrical conductivity, current-voltage characterization, atomic force microscopy, scanning tunneling microscopy, electron microscopy, electron beam lithography, and energy dispersive x-ray spectroscopy. Active collaborations with researchers at Cornell University and at Riso National Laboratory for Sustainable Energy (in Denmark) keep the research program vibrant and relevant. Since 2001, I have been an active member of the Cornell Center for Nanoscale Systems. Recent research and publications have focused on carbon nanotubes, graphene sheets, and organic photovoltaics. Pomona College students have played significant roles in all these projects, as well as in the development of our facilities. Connections to a wide range of researchers are invaluable not only for scientific discussions, but provide many opportunities for summer REU internships for my research students. This provides valuable training, access to facilities, and seeds future collaborations. Collaborations at Cornell span 15 years including two sabbatical years and regular summer visits to work at sites such as the Cornell Nanofabrication Facility, the Cornell Center for Materials Research, and the Cornell Center for Nanoscale Systems.

  7. Characterization of wind velocities in the wake of a full scale wind turbine using three ground-based synchronized WindScanners

    NASA Astrophysics Data System (ADS)

    Yazicioglu, Hasan; Angelou, Nikolas; Mikkelsen, Torben; José Trujillo, Juan


    The wind energy community is in need of detailed full-field measurements in the wake of wind turbines. Here, three dimensional(3D) wind vector field measurements obtained in the near-wake region behind a full-scale test turbine are presented. Specifically, the wake of a NEG Nordtank turbine, installed at Risoe test field, has been measured from 0 to 2 diameters downstream. For this, three ground-based synchronised short-range WindScanners and a spinner lidar have been used. The 3D wind velocity field has been reconstructed in horizontal and vertical planes crossing the hub. The 10-min mean values of the three wind components reveal detailed information regarding the wake properties while propagating downwind over flat terrain. Furthermore, the wake centre is tracked from the measurements and its meander is investigated as function of yaw misalignment of the turbine. The centre-line wake deficit is calculated both in a Nacelle and Moving Frame of Reference. The results can be used in quantitative validation of numerical wake models.

  8. Investigation of the Degradation Mechanisms of a Variety of Organic Photovoltaic Devices by Combination of Imaging Techniques—the ISOS-3Inter-laboratory Collaboration

    SciTech Connect

    Germack D.; Rosch, R.; Tanenbaum, D.M.; Jorgensen, M.; Seeland, M.; Barenklau, M.; Hermenau, M.; Voroshazi, E.; Lloyd, M.T.; Galagan, Y.; Zimmermann, B.; Wurfel, U.; Hosel, M.; Dam, H.F.; Gevorgyan, S.A.; Kudret, S.; Maes, W.; Lutsen, L.; Vanderzande, D.; Andriessen, R.; Teran-Escobar, G.; Lira-Cantu, M.; Rivaton, A.; Uzunoglu, G.Y.; Andreasen, B.; Madsen, M.V.; Norrman, K.; Hoppe, H.; Krebs, F.C.


    The investigation of degradation of seven distinct sets (with a number of individual cells of n {ge} 12) of state of the art organic photovoltaic devices prepared by leading research laboratories with a combination of imaging methods is reported. All devices have been shipped to and degraded at Risoe DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. Imaging of device function at different stages of degradation was performed by laser-beam induced current (LBIC) scanning; luminescence imaging, specifically photoluminescence (PLI) and electroluminescence (ELI); as well as by lock-in thermography (LIT). Each of the imaging techniques exhibits its specific advantages with respect to sensing certain degradation features, which will be compared and discussed here in detail. As a consequence, a combination of several imaging techniques yields very conclusive information about the degradation processes controlling device function. The large variety of device architectures in turn enables valuable progress in the proper interpretation of imaging results - hence revealing the benefits of this large scale cooperation in making a step forward in the understanding of organic solar cell aging and its interpretation by state-of-the-art imaging methods.

  9. Air Force Research Laboratory (AFRL) research highlights, September--October 1998

    SciTech Connect


    New AFOSR-sponsored research shows that exhausts from solid-fueled rocket motors have very limited impact on stratospheric ozone. The research provides the Air Force with hard data to support continued access to space using the existing fleet of rockets and rocket technology. This basic research data allows the Air Force to maintain a strongly proactive environmental stance, and to meet federal guidelines regarding environmental impacts. Long-standing conjecture within the international rocket community suggests that chlorine compounds and alumina particulates produced in solid rocket motor (SRM) exhausts could create localized, temporary ozone toss in rocket plumes following launches. The extent of a local depletion of ozone and its environmental impact depends on details of the composition and chemistry in these plumes. Yet direct measurements of plume composition and plume chemistry in the stratosphere had never been made. Uncertainty about these details left the Air Force and commercial space launch capability potentially vulnerable to questions about the environmental impact of rocket launches. In 1995, APOSR and the Space and Missiles Systems Center Launch Programs Office (SMC/CL) jointly began the Rocket Impacts on Stratospheric Ozone (RISO) program to make the first-ever detailed measurements of rocket exhaust plumes. These measurements were aimed at understanding how the exhaust from large rocket motors effect the Earth`s stratospheric ozone layer. The studies determined: the size distribution of alumina particles in these exhausts, the amount of reactive chlorine in SRM exhaust, and the size and duration of localized ozone toss in the rocket plumes.

  10. A new facility for Quaternary Geochronology in Spain: The National Research Centre for Human Evolution (CENIEH) in Burgos

    NASA Astrophysics Data System (ADS)

    Parés, Josep M.; Duval, Mathieu; Arnold, Lee J.; Hoffmann, Dirk L.


    A new geochronology facility has been recently set up in Burgos, Spain, as part of the recently established National Research Centre for Human Evolution (CENIEH). The CENIEH is sponsored by governmental funding and was established to foster major advances in our understanding of human evolution through multidisciplinary research. As part of this initiative, a modern laboratory complex is emerging as an European facility for Geochronology and Geoarchaeology. The Geochronology laboratories include archaeomagnetism, electron spin resonance, luminescence, uranium-series, and a clean laboratory for sample preparation. The facility includes a 2G, 755-4K SRM superconducting magnetometer, a Bruker ESR spectrometer (EMXmicro-6/1 model) associated with a low-temperature control system, allowing ESR measurements at room and liquid nitrogen temperature, two Riso readers with a single-grain and pulsed OSL attachments, a ThermoFinnigan Neptune MC-ICP-MS, with a CETAC Aridus and an ESI Apex sample introduction system, a NewWave UP213 nm laser ablation facility, a NewWave Instr. Micromill and ancillary sample preparation and field equipment. The Geochronology group, GEB (Geochronology rEsearch group in Burgos) is being set up as a facility that provides auxiliary laboratory and general support to the scientific community interested in Quaternary studies, and in archaeological and paleontological sites. Methodological advancements in Quaternary dating, and inter-technique collaborative studies form an integral part of GEBs research activities. Current research projects include the chronology of the oldest human occupation of Europe (Atapuerca and Orce), north-African archaeological sites and integration with Plio-Pleistocene climatic changes, rates of incision and uplift of Cenozoic basins in Spain, and dating of ancient DNA sequences and early human occupation sites across Siberia and North America.

  11. OSL and TT-OSL dating of sediments and pottery from a paleoseismological trench across the Gyrtoni Fault, Central Greece: Preliminary results

    NASA Astrophysics Data System (ADS)

    Tsodoulos, Ioannis; Stamoulis, Konstantinos; Papachristodoulou, Christina; Ioannides, Konstantinos; Pavlides, Spyros; Chatzipetros, Alexandros; Koukouvelas, Ioannis; Caputo, Riccardo


    T he preliminary results from optically stimulated luminescence (OSL) ages from a paleoseismological trench excavated in the Gyrtoni Fault, Tyrnavos Basin, Central Greece are presented. The initial preliminary interpretation of the trench wall structure provided indications of recent reactivations of the fault. The footwall of the fault consists of well stratified lagustrine deposits, while the hanging wall consists of poorly stratified scarp-derived deposits. Seven samples, one for each lithologic unit, were collected from the upthrown fault block in order to establish a reliable chronological framework and nine sediment and pottery samples were collected from the downthrown fault block to constrain the timing of the linear morphogenic earthquakes observed in the trench and thus reconstruct the recent seismotectonic behaviour. The samples were dated following the OSL dating method, using the Riso TL/OSL DA-20 reader. The OSL ages were obtained from chemically purified quartz and a single-aliquot regenerative-dose (SAR) protocol was followed for the equivalent dose (De) determination. Also, the natural radioactivity of soil from the surroundings of the original sample location was assessed, using gamma spectrometry. The dose rates were calculated using the appropriate dose conversion factors and corrected for the humidity content of the surrounding soils. The OSL ages from the upthrown fault block are in stratigraphic order (except one sample), but the signal of the five oldest samples occurs above the saturation level of the exponential part of the dose response curve and thus the reliability of the calculated De value for use in dating is uncertain. To obtain a more reliable De value, thermally transferred optically stimulated luminescence (TT-OSL) signal has been investigated for five samples. The age of the earthquakes observed in the trench and the recent seismotectonic behavior of the fault are also discussed.

  12. Comparison of properties and microstructures of Trefimetaux and Hycon 3HP{trademark} after neutron irradiation

    SciTech Connect

    Edwards, D.J.; Singh, B.N.; Toft, P.; Eldrup, M.


    The precipitation strengthened CuNiBe alloys are among three candidate copper alloys being evaluated for application in the first wall, divertor, and limiter components of ITER. Generally, CuNiBe alloys have higher strength but poorer conductivity compared to CuCrZr and CuAl{sub 2}O{sub 3} alloys. Brush-Wellman Inc. has manufactured an improved version of their Hycon CuNiBe alloy that has higher conductivity while maintaining a reasonable level strength. It is of interest, therefore, to investigate the effect of radiation on the physical and mechanical properties of this alloy. In the present work the authors have investigated the physical and mechanical properties of the Hycon 3HP{trademark} alloy both before and after neutron irradiation and have compared its microstructure and properties with the European CuNiBe candidate alloy manufactured by Trefirmetaux. Tensile specimens of both alloys were irradiated in the DR-3 reactor at Risoe to displacement dose levels up to 0.3 dpa at 100, 250 and 350 C. Both alloys were tensile tested in the unirradiated and irradiated conditions at 100, 250 and 350 C. Both pre- and post-irradiation microstructures of the alloys were investigated in detail using transmission electron microscopy. Fracture surfaces were examined under a scanning electron microscope. Electrical resistivity measurements were made on tensile specimens before and after irradiation; all measurements were made at 23 C. At this point it seems unlikely that CuNiBe alloys can be recommended for applications in neutron environments where the irradiation temperature exceeds 200 C. Applications at temperatures below 200 C might be plausible, but only after careful experiments have determined the dose dependence of the mechanical properties and the effect of sudden temperature excursions on the material to establish the limits on the use of the alloy.

  13. Section 9.1 new dosimeters. New dosimetry systems

    NASA Astrophysics Data System (ADS)

    McLaughlin, William L.

    During the past two years there have been significant advances in several forms of radiation measurement systems for radiation processing, covering dose ranges of 1-10 6 Gy. Calorimeters as reference standards for both ionizing photon and electron fields have become well-established. In addition to the older ceric-cerous dosimetry solution analyzed potentiometrically, new liquid-phase dosimeters include those analyzed by spectrophotometry, e.g., improved forms of acidic aqueous solutions of K-Ag dichromate and organic radiochromic dye solutions. It has recently been demonstrated that by using certain refined sugars, e.g., D-(-) ribose, optical rotation response in aqueous solutions can be enhanced for dosimetry at doses > 10 4 Gy. There has been expanded development, use, and formulation (rods, tablets, and thin films) of the amino acid, alanine, as a solid-phase dosimeter analyzed by either ESR spectrometry or by glutamine or alanine spectrophotometry of complexes with ferric ion in the presence of a sulfonphthalein dye (xylenol orange). New commercial types of radiochromic plastic dosimeters, e.g., GafChromic TM, Riso B3 TM, GAMMACHROME YR TM, Radix TM, and Gammex TM, have been introduced and applied in practice. Improvements and broader use of optical waveguide dosimeters, e.g., Opti-Chromic TM, have also been reported, especially in food irradiation applications. Several novel dyed plastic dosimeters are available in large quantities and they lose color due to irradiation. An example is a dyed cellulosic thin film (ATC type DY-42 TM) which can be measured spectrophotometrically or densitometrically up to doses as high as 10 6 Gy.

  14. Calcium transport in protoplasts isolated from ml-o barley isolines resistant and susceptible to powdery mildew. [Hordeum vulgare L

    SciTech Connect

    Wrona, A.F.; Spanswick, R.M.; Aist, J.R. )


    Free cytoplasmic calcium has been postulated to play a role in preventing powdery mildew in a series of homozygous ml-o mutants of barley, Hordeum vulgare L. Protoplasts isolated from 7-day-old plants of the ml-o resistant-susceptible (R-S) barley isolines, Riso 5678/3* {times} Carlsberg II R and S, were used to test for differences in fluxes of Ca{sup 2+} across the plasmalemma. Greater influx or lesser efflux might account for a higher free cytosolic Ca{sup 2+} postulated to exist in ml-o R mutants. Uniform patterns of uptake were maintained for 3 hours from solutions of 0.2 and 2 millimolar Ca{sup 2+}. Washout curves of {sup 45}Ca{sup 2+} from R and S protoplasts revealed three compartments - presumed to represent release from the vacuole, organelles, and the cytoplasm (which included bound as well as free Ca{sup 2+}). Uptake and washout did not differ between isolines. On the basis of recent determinations of submicromolar levels of free cytoplasmic Ca{sup 2+} and their initial rates of {sup 45}ca-labeled Ca{sup 2+} uptake, they show that measurement of the unidirectional influx of Ca{sup 2+} across the plasmalemma is not feasible because the specific activity of the pool of free cytoplasmic calcium increases almost instantaneously to a level that would result in a significant, but unknown, efflux of label. Similarly, measurement of the efflux of Ca{sup 2+} across the plasmalemma is not possible since the activity of the pool of free cytoplasmic calcium is a factor of 350 smaller than the most rapid component of the washout experiment. This pool of cytoplasmic free Ca{sup 2+} will wash out too rapidly and be too small to detect under the conditions of these experiments.

  15. Proceedings of the 4th New World Luminescence Dating and Dosimetry Workshop, Denver, Colorado, May 31 June 2, 2006

    USGS Publications Warehouse

    Wise, Richard A.


    Introduction: Optically stimulated luminescence (OSL) is one of a class of measurements known as stimulated phenomena. Such phenomena may be stimulated thermally or optically and the reader is referred to works by Aitken (1998) and Botter-Jensen and others (2003) for more detail. In recent years OSL has become a popular procedure for the determination of environmental radiation doses absorbed by archeological and geological materials in an attempt to date these materials. The first OSL measurements on quartz and feldspar were made using an argon ion-laser (Huntley et al., 1985). However, the development of cheaper stimulation systems based first on filtered lamps and then on light- emitting diodes (LEDs) (Spooner, et al., 1990; Botter-Jensen, and others, 1999) has led to a massive expansion in OSL dating applications. The abstracts in this volume represent presentations from a workshop held in May-June 2006, at the Denver Federal Center, Denver, Colorado, in which OSL methodologies and applications were summarized and integrated to provide a current synthesis of the OSL science being applied throughout North America. The workshop, sponsored by the U.S. Geological Survey Crustal Imaging and Characterization Team and North Dakota State University, was open to all scientists interested in OSL dating techniques and radiation dosimetry. Participants included thirty-six research scientists and students in geology, archaeology, and physics from the U.S. Geological Survey, Los Alamos National Labs, Kentucky Geological Survey, eight universities in the United States, one university in Canada, one university in India, and Riso National Labs of Denmark. The workshop included two keynote speakers: Dr. Ashok Singhvi (Physical Research Laboratory, Ahmedabad, India) spoke on 'Some Unexplored Methodological Aspects and Some New Applications of Luminescence Dating,' while Dr. Jim Feathers (University of Seattle, WA) spoke on OSL Dating of Sediments From Paleoindian Sites in Brazil

  16. Effects of bonding bakeout thermal cycles on pre- and post irradiation microstructures, physical, and mechanical properties of copper alloys

    SciTech Connect

    Singh, B.N.; Eldrup, M.; Toft, P.; Edwards, D.J.


    At present, dispersion strengthened (DS) copper is being considered as the primary candidate material for the ITER first wall and divertor components. Recently, it was agreed among the ITER parties that a backup alloy should be selected from the two well known precipitation hardened copper alloys, CuCrZr and CuNiBe. It was therefore decided to carry out screening experiments to simulate the effect of bonding and bakeout thermal cycles on microstructure, mechanical properties, and electrical resistivity of CuCrZr and CuNiBe alloys. On the basis of the results of these experiments, one of the two alloys will be selected as a backup material. Tensile specimens of CuCrZr and CuNiBe alloys were given various heat treatments corresponding to solution anneal, prime ageing, and bonding thermal cycle followed by reageing and the reactor bakeout treatment at 623K for 100 hours. Tensile specimens of the DS copper were also given the heat treatment corresponding to the bonding thermal cycle. A number of these heat treated specimens of CuCrZr, CuNiBe, and DS copper were neutron irradiated at 523K to a dose level of {approx}0.3 dpa (NRT) in the DR-3 reactor at Riso. Both unirradiated and irradiated specimens with the various heat treatments were tensile tested at 532K. The dislocation, precipitate and void microstructures and electrical resistivity of these specimens were also determined. Results of these investigations will be reported and discussed in terms of thermal and irradiation stability of precipitates and irradiation-induced precipitation and recovery of dislocation microstructure. Results show that the bonding and bakeout thermal cycles are not likely to have any serious deleterious effects on the performance of these alloys. The CuNiBe alloys were found to be susceptible to radiation-induced embrittlement, however, the exact mechanism is not yet known. It is thought that radiation-induced precipitation and segregation of the beryllium may be responsible.

  17. Numerical investigation of wind turbine and wind farm aerodynamics

    NASA Astrophysics Data System (ADS)

    Selvaraj, Suganthi

    A numerical method based on the solution of Reynolds Averaged Navier Stokes equations and actuator disk representation of turbine rotor is developed and implemented in the OpenFOAM software suite for aerodynamic analysis of horizontal axis wind turbines (HAWT). The method and the implementation are validated against the 1-D momentum theory, the blade element momentum theory and against experimental data. The model is used for analyzing aerodynamics of a novel dual rotor wind turbine concept and wind farms. Horizontal axis wind turbines suffer from aerodynamic inefficiencies in the blade root region (near the hub) due to several non-aerodynamic constraints (e.g., manufacturing, transportation, cost, etc.). A new dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating these losses. A DRWT is designed using an existing turbine rotor for the main rotor (Risoe turbine and NREL 5 MW turbine), while the secondary rotor is designed using a high lift to drag ratio airfoil (the DU 96 airfoil from TU Delft). The numerical aerodynamic analysis method developed as a part of this thesis is used to optimize the design. The new DRWT design gives an improvement of about 7% in aerodynamic efficiency over the single rotor turbine. Wind turbines are typically deployed in clusters called wind farms. HAWTs also suffer from aerodynamic losses in a wind farm due to interactions with wind turbine wakes. An interesting mesoscale meteorological phenomenon called "surface flow convergence" believed to be caused by wind turbine arrays is investigated using the numerical method developed here. This phenomenon is believed to be caused by the pressure gradient set up by wind turbines operating in close proximity in a farm. A conceptual/hypothetical wind farm simulation validates the hypothesis that a pressure gradient is setup in wind farms due to turbines and that it can cause flow veering of the order of 10 degrees. Simulations of a real wind farm (Story County) are also

  18. Computational Investigations of Inboard Flow Separation and Mitigation Techniques on Multi-Megawatt Wind Turbines

    NASA Astrophysics Data System (ADS)

    Chow, Raymond

    The aerodynamic characteristics of the NREL 5-MW rotor have been examined using a Reynolds-averaged Navier-Stokes method, OVERFLOW2. A comprehensive off-body grid independence study has been performed. A strong dependence on the size of the near-body wake grid has been found. Rapid diffusion of the wake appears to generate an overprediction of power and thrust. A large, continuous near-wake grid at minimum of two rotor diameters downstream of the rotor appears to be necessary for accurate predictions of near-body forces. The NREL 5-MW rotor demonstrates significant inboard flow separation up to 30% of span. This separation appears to be highly three-dimensional, with a significant amount of radial flow increasing the size of the separated region outboard. Both integrated aerodynamic coefficients and detailed wake structures for the baseline NREL 5-MW rotor are in excellent agreement with results by Riso at Uinfinity = 8 and 11 m/s. A simple, continuous full-chord fence was applied at the maximum chord location of the blade, within the region of separation. This non-optimized device reduced the boundary-layer cross-flow and resulting separation, and increased rotor power capture by 0.9% and 0.6% at U infinity = 8 and 11 m/s, respectively. Suction side only fences perform similarly in terms of power capture but reduce the increase in rotor thrust. Fence heights from 0.5% to 17.5% of the maximum chord all demonstrate some level of effectiveness, with fences (1-2.5%cmax) showing similar performance gains to taller fences with smaller penalties in thrust. Performance in terms of power capture is not very sensitive to spanwise location when placed within the separation region. Blunt trailing edge modifications to the inboard region of the blade showed a relatively significant effect on rotor power. Over a large range of trailing edge thicknesses from hTE = 10 to 25%c, power was found to increase by 1.4%. Thrust increased proportionally with the thicknesses examined

  19. Preface

    NASA Astrophysics Data System (ADS)

    Lindgård, Per-Anker


    This special issue presents a series of papers on biological physics. It emphasizes the fact that Journal of Physics: Condensed Matter welcomes papers in this area and foresees a fruitful cross-fertilization between this and other more conventional condensed matter fields. The work was presented at the conference ÂNanophysics in Life SciencesÂ' held in Copenhagen on 21-22 June 2002. The meeting was arranged by, and marked the start of, the new Division of Physics in Life Sciences (DPL) within the European Physical Society (EPS). It also celebrated the opening of a new Danish research centre on quantum protein physics (QUP), which was co-organizer and co-sponsor. The meeting was organized at short notice and yet attracted some 80 participants from a number of countries (despite the fact that the chosen weekend included the `midsummer night', a feast nobody in the Northern Scandinavian countries would wish to miss - even when offered an event in the beautiful venue of the Carlsberg estate). The audience included many young people and students, demonstrating the great interest in the field of biological physics and in the topics chosen within that field. The selection represented, furthermore, the present scope of the new DPL division. All but one of the board members of DPL were able to attend and present their work, among others. They have subsequently delivered valuable contributions to this special issue. The subjects cover a large area (the full programme can be found on the division's web-page: To mention a few: the dynamical and optical properties of biomolecules (proteins), experimental studies of single biomolecules, various theoretical approaches to the protein folding problem and DNA motion, biomolecular motor and transport functions, quantum chemical calculations. Many of these problems are closely related to those studied in conventional condensed matter. To emphasize one topic we have written the Viewpoint article (pages V5-V9) which