Analysis on linac quadrupole misalignment in FACET commissioning 2012 (open access)

Analysis on linac quadrupole misalignment in FACET commissioning 2012

In this note, the analysis on linac quadrupole misalignment is presented for the FACET linac section LI05-09 plus LI11-19. The effectiveness of the beam-based alignment technique is preliminarily confirmed by the measurement. Beam-based alignment technique was adopted at SLAC linac since SLC time. Here the beam-based alignment algorithms are further developed and applied in the FACET commissioning during 2012 run.
Date: July 5, 2012
Creator: Sun, Yipeng
System: The UNT Digital Library
Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study (open access)

Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study

The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we …
Date: July 5, 2012
Creator: Burghaus, U.
System: The UNT Digital Library
Foreign Travel Trip Report for LLNL travel with DOE FES funding,May 19th-30th, 2012 (open access)

Foreign Travel Trip Report for LLNL travel with DOE FES funding,May 19th-30th, 2012

I attended the 20th biannual International Conference on Plasma Surface Interaction (PSI) in Fusion Devices in Aachen, Germany, hosted this year by the Forschungszentrum Julich (FZJ) research center. The PSI conference is one of the main international forums for the presentation and discussion of results on plasma surface interactions and edge plasma physics relevant to magnetic confinement fusion devices. I disseminated the recent results of FESP/LLNL tokamak research by presenting three posters on: (i) understanding reconnection and controlling edge localized modes (ELMs) using the BOUT++ code, (ii) simulation of resistive ballooning mode turbulence, and (iii) innovative design of Snowflake divertors. I learned of many new and recent results from international tokamak facilities and had the opportunity for discussion of these topics with other scientists at the poster sessions, conference lunches/receptions, etc. Some of the major highlights of the PSI conference topics were: (1) Review of the progress in using metallic tungsten and beryllium (ITER-like) walls at international tokamak facilities: JET (Culham, UK), TEXTOR (FZJ, Germany) and Alcator CMOD (MIT, USA). Results included: effect of small and large-area melting on plasma impurity content and recovery, expected reduction in retention of hydrogenic species, increased heat load during disruptions and need for mitigation …
Date: July 5, 2012
Creator: Joseph, I
System: The UNT Digital Library