Gordon Research Conference on Radiation & Climate in 2009, July 5 -10 (open access)

Gordon Research Conference on Radiation & Climate in 2009, July 5 -10

The 2009 Gordon Research Conference on Radiation and Climate will present cutting-edge research on the outstanding issues in global climate change with focus on the radiative forcing and sensitivity of the climate system and associated physical processes. The Conference will feature a wide range of topics, including grand challenges in radiation and climate, radiative forcing, climate feedbacks, cloud processes in climate system, hydrological cycle in changing climate, absorbing aerosols and Asian monsoon, recent climate changes, and geo-engineering. The invited speakers will present the recent most important advances and future challenges in these areas. The Conference will bring together a collection of leading investigators who are at the forefront of their field, and will provide opportunities for scientists especially junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented.
Date: July 10, 2009
Creator: Fu, Quiang
System: The UNT Digital Library
State of the art in electromagnetic modeling for the Compact Linear Collider (open access)

State of the art in electromagnetic modeling for the Compact Linear Collider

SLAC's Advanced Computations Department (ACD) has developed the parallel 3D electromagnetic time-domain code T3P for simulations of wakefields and transients in complex accelerator structures. T3P is based on state-of-the-art Finite Element methods on unstructured grids and features unconditional stability, quadratic surface approximation and up to 6th-order vector basis functions for unprecedented simulation accuracy. Optimized for large-scale parallel processing on leadership supercomputing facilities, T3P allows simulations of realistic 3D structures with fast turn-around times, aiding the design of the next generation of accelerator facilities. Applications include simulations of the proposed two-beam accelerator structures for the Compact Linear Collider (CLIC) - wakefield damping in the Power Extraction and Transfer Structure (PETS) and power transfer to the main beam accelerating structures are investigated.
Date: July 10, 2009
Creator: Candel, Arno; Kabel, Andreas; Lee, Lie-Quan; Li, Zenghai; Ng, Cho; Schussman, Greg et al.
System: The UNT Digital Library
Characterization of secondary phases in modified vertical bridgman growth czt (open access)

Characterization of secondary phases in modified vertical bridgman growth czt

CdZnTe or 'CZT' crystals are highly suitable for use as a room temperature based spectrometer for the detection and characterization of gamma radiation. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. For example, various structural heterogeneities within the CZT crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SP) can have a negative impact on the detector performance. In this study, a CZT material was grown by the modified vertical Bridgman growth (MVB) method with zone leveled growth without excess Te in the melt. Visual observations of material from the growth of this material revealed significant voids and SP. Three samples from this material was analyzed using various analytical techniques to evaluate its electrical properties, purity and detector performance as radiation spectrometers and to determine the morphology, dimension and elemental/structural composition of one of the SP in this material. This material was found to have a high resistivity but poor radiation spectrometer performance. It had SP that were rich in polycrystalline aluminum oxide (Al{sub 2}O{sub 3}), metallic Te and polycrystalline CdZnTe …
Date: July 10, 2009
Creator: Duff, Martine
System: The UNT Digital Library
Over-Pressurized Drums: Their Causes and Mitigation (open access)

Over-Pressurized Drums: Their Causes and Mitigation

Having to contend with bulging or over-pressurized drums is, unfortunately, a common event for people storing chemicals and chemical wastes. (Figure 1) The Department of Energy alone reported over 120 incidents of bulging drums between 1992 and 1999 (1). Bulging drums can be caused by many different mechanisms, represent a number of significant hazards and can be tricky to mitigate. In this article, we will discuss reasons or mechanisms by which drums can become over-pressurized, recognition of the hazards associated with and mitigation of over-pressurized drums, and methods that can be used to prevent drum over-pressurization from ever occurring. Drum pressurization can represent a significant safety hazard. Unless recognized and properly mitigated, improperly manipulated pressurized drums can result in employee exposure, employee injury, and environmental contamination. Therefore, recognition of when a drum is pressurized and knowledge of pressurized drum mitigation techniques is essential.
Date: July 10, 2009
Creator: Simmons, Fred; Kuntamukkula, Murty; Quigley, David; Robertson, Janeen & Freshwater, David
System: The UNT Digital Library
Advance Network Reservation and Provisioning for Science (open access)

Advance Network Reservation and Provisioning for Science

We are witnessing a new era that offers new opportunities to conduct scientific research with the help of recent advancements in computational and storage technologies. Computational intensive science spans multiple scientific domains, such as particle physics, climate modeling, and bio-informatics simulations. These large-scale applications necessitate collaborators to access very large data sets resulting from simulations performed in geographically distributed institutions. Furthermore, often scientific experimental facilities generate massive data sets that need to be transferred to validate the simulation data in remote collaborating sites. A major component needed to support these needs is the communication infrastructure which enables high performance visualization, large volume data analysis, and also provides access to computational resources. In order to provide high-speed on-demand data access between collaborating institutions, national governments support next generation research networks such as Internet 2 and ESnet (Energy Sciences Network). Delivering network-as-a-service that provides predictable performance, efficient resource utilization and better coordination between compute and storage resources is highly desirable. In this paper, we study network provisioning and advanced bandwidth reservation in ESnet for on-demand high performance data transfers. We present a novel approach for path finding in time-dependent transport networks with bandwidth guarantees. We plan to improve the current ESnet advance …
Date: July 10, 2009
Creator: Balman, Mehmet; Chaniotakis, Evangelos; Shoshani, Arie & Sim, Alex
System: The UNT Digital Library
Parameter Study of the LIFE Engine Nuclear Design (open access)

Parameter Study of the LIFE Engine Nuclear Design

LLNL is developing the nuclear fusion based Laser Inertial Fusion Energy (LIFE) power plant concept. The baseline design uses a depleted uranium (DU) fission fuel blanket with a flowing molten salt coolant (flibe) that also breeds the tritium needed to sustain the fusion energy source. Indirect drive targets, similar to those that will be demonstrated on the National Ignition Facility (NIF), are ignited at {approx}13 Hz providing a 500 MW fusion source. The DU is in the form of a uranium oxycarbide kernel in modified TRISO-like fuel particles distributed in a carbon matrix forming 2-cm-diameter pebbles. The thermal power is held at 2000 MW by continuously varying the 6Li enrichment in the coolants. There are many options to be considered in the engine design including target yield, U-to-C ratio in the fuel, fission blanket thickness, etc. Here we report results of design variations and compare them in terms of various figures of merit such as time to reach a desired burnup, full-power years of operation, time and maximum burnup at power ramp down and the overall balance of plant utilization.
Date: July 10, 2009
Creator: Kramer, K. J.; Meier, W. R.; Latkowski, J. F. & Abbott, R. P.
System: The UNT Digital Library
First-principles electronic and elastic properties of plutonium metal (open access)

First-principles electronic and elastic properties of plutonium metal

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Date: July 10, 2009
Creator: Soderlind, P.; Landa, A. & Klepeis, J. E.
System: The UNT Digital Library