[en] The goal of this program is to develop, optimize and deploy a silicon-based micromachined stripping analyzer for field monitoring trace levels of chromium and uranium. Such system will integrate the sample-handling steps and necessary chemical reactions (using a flow-injection operation) with the actual adsorptive stripping measurement on a small planar chip. Besides the drastic reduction in the size of the analytical system, such miniaturization should lead to increased speed, minimal reagent consumption and disposal, higher sensitivity and improved precision, and would thus revolutionize the way by which toxic metals are being monitored. The new electrochemical devices should have an enormous impact upon pollution control and prevention, as they should lead to a substantially more effective and economic monitoring of priority metal pollutants. The project combined fundamental and practical aspects of electroanalysis and microsystems to meet the monitoring and sensing needs of DOE sites

[en] This thesis presents a measurement of the cross section of t-channel single top-quark production using 1.04 fb^-1 data collected by the ATLAS detector at the LHC with proton-proton collision at center-of-mass √(s)=7 TeV. Selected events contain one lepton, missing transverse energy, and two or three jets, one of them b-tagged. The background model consists of multi-jets, W+jets and top-quark pair events, with smaller contributions from Z+jets and di-boson events. By using a selection based on the distribution of a multivariate discriminant constructed with the boosted decision trees, the cross section of t-channel single top-quark production is measured: σ_t = (97.3 +30.7 -30.2) pb, which is in good agreement with the prediction of the Standard Model. Assuming that the top-quark-related CKM matrix elements obey the relation |V_tb|>> |V_ts|, |V_td|, the coupling strength at the W_tb vertex is extracted from the measured cross section, |V_tb| = (1.23 +0.20 -0.19). If it is assumed that |V_tb| ≤ 1 a lower limit of |V_tb| > 0.61 is obtained at the 95% confidence level. (author)

[en] Although highly ordered nanostructures can often form in a self- assembled fashion, the formation of the structures can be extremely dynamic, far from commonly believed near-equilibrium conditions even at the end of the ordering processes. Therefore, a controlled self-assembling of the nanostructure has to be guided by a thorough understanding of ordering kinetics and nanoparticle dynamics in the complex matrices. For probing the systems involving dynamical structure of surfaces and buried interfaces, many x-ray surface and interfacial characterization techniques provides a unique scientific opportunity to study the principle of formation of ordered nanostructures. As an increasingly important structural-characterization technique, grazing-incidence small-angle scattering (GISAXS) finds vast applications in nanostructures and nanocomposites at surfaces and interfaces for in situ and real-time studies because of its probing q-range (0.001-1 nm^-1) and temporal resolution (0.001-1 s). At the Advanced Photon Source (APS), we pioneered in using real-time GISAXS to study nanoparticle/polymer nanocomposites. Also, the kinematics of nanoparticle crystal formation at air/liquid interfaces has been elucidated by the similar method during the liquid droplet evaporation. Recently, we used in situ GISAXS to investigate nucleation behavior of sol-gel derived oxide thin films. This talk will give an overview of studying the self-assembly of nanosctructures at the APS dedicated GISAXS beamline.

[en] The correction magnets in the Advanced Photon Source's storage ring are powered by PWM-controlled bipolar switching-mode converters. These converters are designed to operate at up to ±150 A. The original control circuit used a polarity detection circuit with a hysteresis to determine which IGBT was needed to regulate the current with a given polarity. Only the required IGBT was switched with PWM pulses while others were held on or off continuously. The overall IGBT switching losses were minimized by the design. The shortcoming of the design was that the converter's output was unstable near zero current because of the hysteresis. To improve the stability, a new current regulator using a different PWM method has been developed to eliminate the requirement of the polarity detection. With the new design, converters can operate smoothly in the full range of ±150 A. The new design also meets tighter specs in terms of the ripple current and dynamic response. This paper describes the design of the new regulator and the test results.

[en] The purpose of this Analysis/Model Report (AMR) is to update and document the data and subsequent analyses from ambient field-testing activities performed in underground drifts of the Yucca Mountain Site Characterization Project (YMP). This revision updates data and analyses presented in the initial issue of this AMR. This AMR was developed in accordance with the ''Technical Work Plan for Unsaturated Zone (UZ) Flow and Transport Process Model Report'' and ''Technical Work Plan for UZ Flow, Transport, and Coupled Processes Process Model Report. These activities were performed to investigate in situ flow and transport processes. The evaluations provide the necessary framework to: (1) refine and confirm the conceptual model of matrix and fracture processes in the unsaturated zone (UZ) and (2) analyze the impact of excavation (including use of construction water and effect of ventilation) on the UZ flow and transport processes. This AMR is intended to support revisions to ''Conceptual and Numerical Models for UZ Flow and Transport'' and ''Unsaturated Zone Flow and Transport Model Process Model Report''. In general, the results discussed in this AMR are from studies conducted using a combination or a subset of the following three approaches: (1) air-injection tests, (2) liquid-release tests, and (3) moisture monitoring using in-drift sensors or in-borehole sensors, to evaluate the impact of excavation, ventilation, and construction-water usage on the surrounding rocks. The liquid-release tests and air-injection tests provide an evaluation of in situ fracture flow and the competing processes of matrix imbibition. Only the findings from testing and data not covered in the ''Seepage Calibration Model and Seepage Testing Data'' are analyzed in detail in the AMR

No abstract available

[en] For more than fifteen years before the International Technology Recommendation Panel (ITRP) decision in August, 2004, there were intensive R and D activities and broad international collaboration among the groups at SLAC, KEK, FNAL, LLNL and other labs for the room temperature X-Band accelerator structures. The goal was to provide an optimized design of the main linac structure for the NLC (Next Linear Collider) or GLC (Global Linear Collider). There have been two major challenges in developing X-band accelerator structures for the linear colliders. The first is to demonstrate stable, long-term operation at the high gradient (65 MV/m) that is required to optimize the machine cost. The second is to strongly suppress the beam induced long-range wakefields, which is required to achieve high luminosity. More than thirty X-band accelerator structures with various RF parameters, cavity shapes and coupler types have been fabricated and tested since 1989. A summary of the main achievements and experiences are presented in this talk including the structure design, manufacturing techniques, high power performance, and other structure related issues. Also, the new progress in collaborating with the CLIC, high gradient structures and X-Band structure applications for RF deflectors and others are briefly introduced

[en] The accelerator structure groups for NLC (Next Linear Collider) and GLC (Global Linear Colliders) have successfully collaborated on the research and development of a major series of advanced accelerator structures based on room-temperature technology at X-band frequency. The progress in design, simulation, microwave measurement and high gradient tests are summarized in this paper. The recent effort in design and fabrication of the accelerator structure prototype for the main linac is presented in detail including HOM (High Order Mode) suppression and design of HOM couplers and fundamental mode couplers, optimized accelerator cavities as well as plans for future structures

No abstract available

[en] Design studies on the X-Band transverse RF deflectors operating at HEM_ll mode have been made for two different applications. One is for beam measurement of time-sliced emittance and slice energy spread for the upgraded LCLS project, its optimization in RF efficiency and system design are carefully considered. Another is to design an ultra-fast RF kicker in order to pick up single bunches from the bunch-train of the B-factory storage ring. The challenges are to obtain very short structure filling time with high RF group velocity and good RF efficiency with reasonable transverse shunt impedance. Its RF system will be discussed