Science.gov (United States)

The exposure and subsequent undermining of pier/abutment foundations through the scouring action of a flood can result in the structural failure of a bridge. Bridge scour is one of the leading causes of bridge failure. Bridges subject to periods of flood/high flow require monitoring during those times in order to protect the traveling public. In this study, an innovative scour monitoring system using button-like fiber Bragg grating (FBG) sensors was developed and applied successfully in the field during the Aere typhoon period in 2004. The in situ FBG scour monitoring system has been demonstrated to be robust and reliable for real-time scour-depth measurements, and to be valid for indicating depositional depth at the Dadu Bridge. The field results show that this system can function well and survive a typhoon flood.

Energy Technology Data Exchange (ETDEWEB)

The Fermilab Linac Upgrade is planned to increase the energy of the H- linac from 200 to 400 MeV. This is intended to reduce the incoherent space-charge tuneshift at injection into the 8 GeV Booster which can limit either the brightness or the total intensity of the beam. The Linac Upgrade will be achieved by replacing the last four 201.25 MHz drift-tube tanks which accelerate the beam from 116 to 200 MeV, with seven 805 MHz side-coupled cavity modules operating at an average axial field of abut 7.5 MV/m. This will allow acceleration to 400 MeV in the existing Linac enclosure. Each accelerator module will be driven with a klystron-based rf power supply. A prototype rf modulator has been built and tested at Fermilab, and a prototype 12 MW klystron is being fabricated by Litton Electron Devices. Fabrication of production accelerator modules is in progress. 8 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

WASAG DECON developed a concept for the biological in situ remediation of an TNT-contaminated former seepage pond. This pond is located on the site of an ammunition factory in Lower Saxony. Unit 1982 all the waste water from the production buildings was directed into this pond, including TNT-contaminated water from the flushing of shells. Due to this practice, the sediment of the pond, the underlying soil and the groundwater became contaminated with TNT. The area of the soil contamination adds to abut 2.000 m{sup 2}. The remediation concept includes three steps: 1. Excavation of the most highly contaminated soil with TNT-concentrations above 1000 mg/kg. 2. Reduction of the remaining contamination by a biological in situ treatment using organic and inorganic amendments and mechanical tillage. After about to years of treatment, remediation goals of 50 mg/kg are expected to be reached on most of the area. 3. Contaminations eventually remaining in deeper soil layers ...

Energy Technology Data Exchange (ETDEWEB)

An add-on multileaf collimator for electrons (eMLC) has been developed that provides computer-controlled beam collimation and isocentric dose delivery. The design parameters result from the design study by Gauer et al (2006 Phys. Med. Biol. 51 5987-6003) and were configured such that a compact and light-weight eMLC with motorized leaves can be industrially manufactured and stably mounted on a conventional linear accelerator. In the present study, the efficiency of an initial computer-controlled prototype was examined according to the design goals and the performance of energy- and intensity-modulated treatment techniques. This study concentrates on the attachment and gantry stability as well as the dosimetric characteristics of central-axis and off-axis dose, field size dependence, collimator scatter, field abutment, radiation leakage and the setting of the accelerator jaws. To provide isocentric irradiation, the eMLC can be placed either 16 or 28 cm above the ...

International Nuclear Information System (INIS)

The objective of this study was to explore the role of three-dimensional (3-D) rotational angiography (RA) of the inferior vena cava (IVC; 3-D CV) before filter retrieval and its impact on treatment planning compared with standard anteroposterior cavography (sCV). Thirty patients underwent sCV and 3-D CV before IVC filter retrieval. Parameters assessed were: projection of filter arms or legs beyond the caval lumen, thrombus burden within the filter and IVC, and orientation of the filter within IVC. Skin and effective radiation doses were calculated. Statistical analysis was performed using paired Student t test and nonparametric McNemar's test. Standard anteroposterior cavography detected 49 filter arms or legs projecting beyond the caval lumen in 25 patients. Three-dimensional CV demonstrated 89 filter arms or legs projecting beyond the caval lumen in 28 patients. Twenty-two patients had additional filter arms or legs projecting beyond the caval lumen detected on 3-D CV that were not ...