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Notification of change in a data base

Description: The Supervisory Control and Diagnostics System for the Mirror Fusion Test Facility is an event driven system; tasks that handle specific events are active only when those events occur. One method of monitoring and generating events is the data base notification facility; a task can request that it be loaded and started by the dbms if a data element is touched or goes outside of a specified range. The motivations for this facility (along with an example of its use and some specifics regarding how it is done) are presented.
Date: October 5, 1981
Creator: Nelson, B.C.
Partner: UNT Libraries Government Documents Department

Evaluation of pulse coil alternatives for the large coil program

Description: The Large Coil Program (LCP) is chartered to develop viable superconducting toroidal field (TF) coils for tokamak reactors. The Large Coil Facility (LCTF) portion of the LCP will include pulse coils designed to simulate the transient fields in future ignition tokamaks. The magnitude, distribution, pulse ramp rate, and duration of pulsed fields expected in a TF coil for an ignition reactor serve as criteria for the simulation. The LCP coil test stand is an arrangement of six tokamak TF coils in a compact toroidal geometry. The design of a pulse field coil tailored to this geometry and providing the proper simulation of time-variant fields is the subject of this report. Several pulse coil candidate concepts are evaluated, including (1) a pair of poloidal coils outside the LCTF torus, (2) a single poloidal coil threaded through the torus, and (3) a pair of vertical axis coil windings inside the bore of the toroidal test coils. The latter configuration was selected for use in the LCTF due to its versatility, ease of fabrication, and lower operating cost.
Date: July 1, 1978
Creator: Nelson, B.E.
Partner: UNT Libraries Government Documents Department

Potential of Photovoltaics

Description: Presented at the Association of Industrial Metallizers, Coaters and Laminators (AIMCAL) Fall Technical Conference 2008 and 22nd International Vacuum Web Coating Conference held October 19-22, 2008 in Myrtle Beach, South Carolina. This presentation discusses PV in the world energy portfolio, PV basics, PV technologies, and vacuum web-coating applications in PV.
Date: October 22, 2008
Creator: Nelson, B. P.
Partner: UNT Libraries Government Documents Department

Process Development and Integration Lab (PDIL) + Measurements and Characterization (Presentation)

Description: The Process Development and Integration Lab (PDIL) Vision is to integrate deposition, characterization, and processing by being flexible and robust; having a standardized transfer interface; and controlled sample ambient between tools. The benefits are: (1) answers to previously inaccessible research questions; (2) control and characterization of critical surfaces (interfaces) and how their impact on subsequent layers; (3) assess process-related source chemistry, surface chemistry and kinetics, and bulk reconstruction; (4) grow layers and alter interfaces using controlled processes and transfer ambients (without exposure to air); (5) develop new techniques, methodologies, device structures, materials, and tools (growth, processing, and analytical); and (6) improved collaborations with university and industry researchers.
Date: April 1, 2008
Creator: Nelson, B.
Partner: UNT Libraries Government Documents Department

Fusion Ignition Research Experiment Vacuum Vessel Design and Configuration

Description: The design status of the vacuum vessel for the Fusion Ignition Research Experiment (FIRE) is presented. The purpose and configuration of the various components of the vessel are described, along with the results of preliminary structural analysis. It appears that a vessel can be designed to meet the requirements within the rather restricted space constraints.
Date: July 19, 2001
Creator: Nelson, B.E.
Partner: UNT Libraries Government Documents Department

Pulse coil concepts for the LCP Facility

Description: The pulse coils described in this paper are resistive copper magnets driven by time-varying currents. They are included in the Large Coil Test Facility (LCTF) portion of the Large Coil Program (LCP) to simulate the pulsed field environment of the toroidal coils in a tokamak reactor. Since TNS (a 150 sec, 5MA, igniting tokamak) and the Oak Ridge EPR (Experimental Power Reactor) are representative of the first tokamaks to require the technology developed in LCP, the reference designs for these machines, especially TNS, are used to derive the magnetic criteria for the pulse coils. This criteria includes the magnitude, distribution, and rate of change of pulsed fields in the toroidal coil windings. Three pulse coil concepts are evaluated on the basis of magnetic criteria and factors such as versatility of design, ease of fabrication and cost of operation. The three concepts include (1) a pair of poloidal coils outside the LCTF torus, (2) a single poloidal coil threaded through the torus, and (3) a pair of vertical axis coil windings inside the bore of one or more of the toroidal test coils.
Date: January 1, 1977
Creator: Nelson, B.E. & Burn, P.B.
Partner: UNT Libraries Government Documents Department

Pulse forming network design program for linear and time-varying loads for the IBM personal computer

Description: A design aid program written to perform pulse forming network calculations is described. The program will perform calculations for either linear, time-varying, or near linear loads. The program is described as ''user-friendly'' and is written in BASIC language for the IBM PC. 6 refs., 3 figs. (DWL)
Date: January 1, 1986
Creator: McDuff, G.G. & Nelson, B.D.
Partner: UNT Libraries Government Documents Department

Integrating Deposition, Processing, and Characterization Equipment within the National Center for Photovoltaics

Description: The purpose of the process integration project of the National Center for Photovoltaics (NCPV) is to develop an infrastructure that will allow researchers to gain new knowledge that is difficult--if not impossible--to obtain with existing equipment. This difficulty is due, in part, to the state of our existing tool set, which lacks sufficient in-situ or real-time measurement capabilities, or lacks access to analytical tools where the sample remains in a controlled environment between deposition and processing or measurement. This new infrastructure will provide flexible and robust integration of deposition, processing (etching, annealing, etc.), and characterization tools via a standardized transfer interface such that samples move between tools in a controlled ambient. Ultimately, this synergistic effort between NREL staff, universities, and the photovoltaic (PV) industry--around an integrated tool base--will add to the PV knowledge base and help move many PV technologies forward.
Date: November 1, 2005
Creator: Nelson, B.; Robbins, S. & Sheldon, P.
Partner: UNT Libraries Government Documents Department

Formation and sustainment of a very low aspect ratio tokamak using coaxial helicity injection (the Helicity Injected Torus (HIT) experiment)

Description: In the paper we will detail the progress of the HIT experiment construction, including the following components: preliminary data and interpretation; diagnostic systems; vacuum vessel and pumping system; helicity source and power supplies; toroidal field coil and power supply; data acquisition system; collaboration with general atomics, with a brief summary given on each.
Date: January 1, 1992
Creator: Jarboe, T.R. & Nelson, B.A.
Partner: UNT Libraries Government Documents Department

Formation and sustainment of a very low aspect ratio tokamak using coaxial helicity injection (the Helicity Injected [HIT] experiment). Annual progress report No. 5, December 1, 1993--December 31, 1994

Description: This is the fifth Progress Report on the Helicity Injected Tokamak (HIT) at the University of Washington, Seattle, DOE Grant DE-FE06-90ER54095. This report covers the period of December 1, 1993 through December 31.
Date: February 6, 1995
Creator: Jarboe, T.R. & Nelson, B.A.
Partner: UNT Libraries Government Documents Department

Integrating Deposition, Processing, and Characterization Equipment within the National Center for Photovoltaics

Description: The purpose of the process integration project of the National Center for Photovoltaics (NCPV) is to develop an infrastructure that will allow researchers to gain new knowledge that is difficult--if not impossible--to obtain with existing equipment. This difficulty is due, in part, to the state of our existing tool set, which lacks sufficient in-situ or real-time measurement capabilities, or lacks access to analytical tools where the sample remains in a controlled environment between deposition and processing or measurement. This new infrastructure will provide flexible and robust integration of deposition, processing (etching, annealing, etc.), and characterization tools via a standardized transfer interface such that samples move between tools in a controlled ambient. This concept will also require the cooperation of experts from various material technologies and characterization disciplines to work directly with each other to obtain answers to key scientific and technological questions. Ultimately, this synergistic effort between NREL staff, universities, and the photovoltaic (PV) industry--around an integrated tool base--will add to the PV knowledge base and help move many PV technologies forward.
Date: January 1, 2005
Creator: Nelson, B.; Robbins, S. & Sheldon, P.
Partner: UNT Libraries Government Documents Department

Managing EHS of PV-Related Equipment at the National Renewable Energy Laboratory: Preprint

Description: Managing environment, health, and safety (EHS) risks at a national laboratory, or university, can be intimidating to a researcher who is focused on research results. Laboratory research and development (R&D) operations are often driven by scientists with limited engineering support and lack well-refined equipment development resources. To add to the burden for a researcher, there is a plethora of codes, standards, and regulations that govern the safe installation and operation of photovoltaic-related R&D equipment -- especially those involving hazardous production materials. To help guide the researcher through the vast list of requirements, the EHS office at NREL has taken a variety of steps. Organizationally, the office has developed hazard-specific laboratory-level procedures to govern particular activities. These procedures are a distillation of appropriate international codes, fire agencies, SEMI standards, U.S. Department of Energy orders, and other industry standards to those necessary and sufficient to govern the safe operation of a given activity. The EHS office works proactively with researchers after a concept for a new R&D capability is conceived to help guide the safe design, acquisition, installation, and operation of the equipment. It starts with a safety assessment at the early stages such that requirements are implemented to determine the level of risk and degree of complexity presented by the activity so appropriate controls can be put in place to manage the risk. As the equipment requirements and design are refined, appropriate equipment standards are applied. Before the 'to-build' specifications are finalized, a process hazard analysis is performed to ensure that no single-point failure presents an unacceptable risk. Finally, as the tool goes through construction and installation stages, reviews are performed at logical times to ensure that the requisite engineering controls and design are in place and operational. Authorization to operate is not given until adherence to these requirements is fully ...
Date: June 1, 2012
Creator: McCuskey, T. & Nelson, B. P.
Partner: UNT Libraries Government Documents Department

Ultrafast Dynamics of Photoexcited Carriers in HWCVD a-Si:H and a-SiGe:H

Description: We present femtosecond studies of photoexcited carrier dynamics in hydrogenated amorphous silicon and silicon-germanium alloys grown by the hot-wire assisted chemical vapor deposition (HWCVD) technique, which is promising for producing high-quality device-grade materials.
Date: January 1, 2000
Creator: Dexheimer, S. L.; Young, J. E. & Nelson, B. P.
Partner: UNT Libraries Government Documents Department

Solenoid-free Plasma Start-up in NSTX using Transient CHI

Description: Experiments in NSTX have now demonstrated the coupling of toroidal plasmas produced by the technique of Coaxial Helicity Injection (CHI) to inductive sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer was used to apply an inductive loop voltage to discharges with a toroidal current of about 100 kA created by CHI. The coupled discharges have ramped up to >700 kA and transitioned into an H-mode demonstrating compatibility of this startup method with conventional operation. The electron temperature in the coupled discharges reached over 800 eV and the resulting plasma had low inductance, which is preferred for long-pulse high performance discharges. These results from NSTX in combination with the previously obtained record 160 kA non-inductively-generated startup currents in an ST or tokamak in NSTX demonstrate that CHI is a viable solenoid-free plasma startup method for future STs and tokamaks.
Date: January 5, 2009
Creator: Raman, R; Jarboe, T; Nelson, B; Mueller, D & Soukhanovskii, V A
Partner: UNT Libraries Government Documents Department