High Power Disk Loaded Guide Load (open access)

High Power Disk Loaded Guide Load

A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.
Date: February 22, 2006
Creator: Farkas, Z. D.
System: The UNT Digital Library
Status of the ATF Extraction Line Laser-wire (open access)

Status of the ATF Extraction Line Laser-wire

A new laser-wire is being installed in the extraction line of the ATF at KEK. This device aims at demonstrating that laser-wires can be used to measure micrometre scale beam size.
Date: February 22, 2006
Creator: Delerue, Nicolas; Gannaway, Fred; Howell, David; Blair, Grahame; Boorman, Gary; Driouichi, Chafik et al.
System: The UNT Digital Library
Linearizing Intra-Train Beam-Beam Deflection Feedback (open access)

Linearizing Intra-Train Beam-Beam Deflection Feedback

Beam-beam deflection feedback acting within the crossing time of a single bunch train may be needed to keep linear collider beams colliding at high luminosity. In a short-pulse machine such as the Next Linear Collider (NLC) this feedback must converge quickly to be useful. The non-linear nature of beam-beam deflection vs. beam-beam offset in these machines precludes obtaining both rapid convergence and a stable steady-state lock to beam offsets with a linear feedback algorithm. We show that a simply realizable programmable non-linear amplifier in the feedback loop can linearize the feedback loop, approximately compensating the beam-beam deflection non-linearity. Performance of a prototype non-linear amplifier is shown. Improvement of convergence and stability of the beam-beam feedback loop is simulated.
Date: February 22, 2006
Creator: Smith, S. R.
System: The UNT Digital Library
Measurement of Low Energy e+e- Interactions at BABARwith Initial State Radiation (open access)

Measurement of Low Energy e+e- Interactions at BABARwith Initial State Radiation

The status of the analysis of e{sup +}e{sup -} annihilation using the radiative return technique at BaBar is presented. Cross sections for the processes e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0}, {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}, {pi}{sup +}{pi}{sup -}K{sup +}K{sup -}, K{sup +}K{sup -}K{sup +}K{sup -}, 3({pi}{sup +}{pi}{sup -}), {pi}{sup 0}{pi}{sup 0}2({pi}{sup +}{pi}{sup -}), K{sup +}K{sup -}2({pi}{sup +}{pi}{sup -}) and p{bar p} are measured in the energy range from threshold up to 4.5 GeV. Studies on resonant structures involved in these processes have been performed. We present also new precise measurements of the effective proton form factor and of the ratio of the electric to magnetic proton form factor, |G{sub E}/G{sub M}|. In addition, the J/{psi} and {psi}(2S) branching fractions to all these final states have been measured.
Date: February 22, 2006
Creator: Anulli, F.
System: The UNT Digital Library
Interaction of LEAFY, AGAMOUS, and TERMINAL FLOWER1 in maintaining floral identity in Arabidopsis (open access)

Interaction of LEAFY, AGAMOUS, and TERMINAL FLOWER1 in maintaining floral identity in Arabidopsis

OAK-B135 The Arabidopsis transcription factor LEAFY (LFY) acts upstream of homeotic genes such as AGAMOUS (AG) to confer floral identity on meristems that arise after the transition to reproductive development. Compared to the genetic circuitry regulating the establishment of floral meristem identity, little is known about its maintenance. Previous experiments with fly heterozygous plants and ag mutants grown in conditions that reduce the floral inductive stimulus have shown that both genes are required to prevent reversion of floral to inflorescence meristems. Here, we present evidence that LFY maintains floral meristem identity independently of AG, and that the primary role of LFY is either direct repression of shoot identity genes or repression of an intermediate factor that activates shoot identity genes. The latter conclusions were deduced from the phenotypes conferred by a gain-of-function transgene, LFY:VP16, that appears to act as a dominant negative, or antimorphic, allele during maintenance of floral meristem identity. These observations contrast with previous findings that LFY acts as a direct activator of floral homeotic genes, supporting the hypothesis that the transcriptional activity of LFY is dependent on specific co-regulators.
Date: February 22, 2002
Creator: Parcy, F., Bomblies, K., and Weigel, D.
System: The UNT Digital Library
RF gas plasma source development for heavy ion fusion (open access)

RF gas plasma source development for heavy ion fusion

Presently the Heavy Ion Fusion Virtual National Laboratory is researching ion sources and injector concepts to understand how to optimize beam brightness over a range of currents (50-2000 mA argon equivalent). One concept initially accelerates millimeter size, milliamp beamlets to 1 MeV before merging them into centimeter size, ampere beams. Computer simulations have shown the final brightness of the merged beams is dominated by the emittance growth of the merging process, as long as the beamlets ion temperature is below a few eV. Thus, a RF multicusp source capable of high current density can produce beams with better brightness compared to ones extracted from a colder source with a large aperture and lower current density. As such, experiments have begun to develop a RF multicusp source capable of delivering one amp of extracted beam current. It is expected that it will require 10 kW of 13 MHz RF power delivered via a quartz shielded, one and half turn, four inch diameter antenna. Important considerations in the development of the source include the dependence of current density and beam ion temperature on consumed RF power and gas pressure. A fast rise time ({approx}100 ns) for the extracted beam pulse must also …
Date: February 22, 2002
Creator: Ahle, L.E.; Hall, R.P. & Molvik, A.W.
System: The UNT Digital Library
Development of a bipolar cell for electrochemical production of lithium (open access)

Development of a bipolar cell for electrochemical production of lithium

Lithium metal can be electrolytically refined from aqueous solutions of its compounds by partial reduction to form a lithium amalgam, followed by reduction of the amalgam to liquid lithium in a molten salt cell at 225 C. A bipolar cell (with a continuous, amalgam electrode circulating between the aqueous and salt cells) was designed, constructed and successfully tested on the bench scale, as a proof of principle of an efficient, safe and low-temperature alternative to existing processes.
Date: February 22, 1995
Creator: Cooper, J.F.; Mack, G.; Peterman, K.; Weinland, S. & McKenzie, P.
System: The UNT Digital Library
Research perspectives on the evaluation of steam generator tube integrity. (open access)

Research perspectives on the evaluation of steam generator tube integrity.

Industry effects have been largely successful in managing degradation of steam generator tubes due to wastage, pitting, and denting, but fretting, SCC and intergranular attack have proved more difficult to manage. Although steam generator replacements are proceeding there is substantial industry interest in operating with degraded steam generators, and significant numbers of plants will continue to do so. In most cases degradation of steam generator tubing by stress corrosion cracking is still managed by plug or repair on detection, because current NDE techniques for characterization of flaws are not accurate enough to permit continued operation. This paper reviews some of the historical background that underlies current steam generator degradation management strategies and outlines some of the additional research that must be done to provide more effective management of degradation in current generators and provide greater assurance of satisfactory performance in replacement steam generators.
Date: February 22, 2001
Creator: Muscara, J.; Diercks, D. R.; Majumdar, S.; Kupperman, D. S.; Bakhtiari, S. & Shack, W. J.
System: The UNT Digital Library
Flow of a two-dimensional liquid metal jet in a strong magnetic field. (open access)

Flow of a two-dimensional liquid metal jet in a strong magnetic field.

Two-dimensional, steady flow of a liquid metal slender jet pouring from a nozzle in the presence of a transverse, nonuniform magnetic field is studied. The surface tension has been neglected, while gravity is shown to be not important. The main aim of the study is to evaluate the importance of the inertial effects. It has been shown that for gradually varying fields characteristic for the divertor region of a tokamak, inertial effects are negligible for N > 10, where N is the interaction parameter. Thus the inertialess flow model is expected to give good results even for relatively low magnetic fields and high jet velocity. Simple relations for the jet thickness and velocity have been derived. The results show that the jet becomes thicker if the field increases along the flow and thinner if it decreases.
Date: February 22, 2002
Creator: Reed, C. B. & Molokov, S.
System: The UNT Digital Library
Real-Time Local Range On-Demand and Dynamic Regional Range Images (open access)

Real-Time Local Range On-Demand and Dynamic Regional Range Images

This paper presents a new approach to a gesture tracking system using real-time range on-demand. The system represents a gesture-controlled interface for interactive visual exploration of large data sets. The paper describes a method performing range processing only when necessary and where necessary. Range data is processed only for non-static regions of interest. This is accomplished by a set of filters on the color, motion, and range data. The speedup achieved is between 41% and 54%. The algorithm also includes a robust skin color segmentation insensitive to illumination changes. Selective range processing results in dynamic regional range images (DRRIs). This development is also placed in a broader context of a biological visual system emulation, specifically redundancies and attention mechanisms.
Date: February 22, 2000
Creator: Tsap, L.V.
System: The UNT Digital Library
Statistical Modeling of Large-Scale Simulation Data (open access)

Statistical Modeling of Large-Scale Simulation Data

With the advent of fast computer systems, Scientists are now able to generate terabytes of simulation data. Unfortunately, the shear size of these data sets has made efficient exploration of them impossible. To aid scientists in gathering knowledge from their simulation data, we have developed an ad-hoc query infrastructure. Our system, called AQSim (short for Ad-hoc Queries for Simulation) reduces the data storage requirements and access times in two stages. First, it creates and stores mathematical and statistical models of the data. Second, it evaluates queries on the models of the data instead of on the entire data set. In this paper, we present two simple but highly effective statistical modeling techniques for simulation data. Our first modeling technique computes the true mean of systematic partitions of the data. It makes no assumptions about the distribution of the data and uses a variant of the root mean square error to evaluate a model. In our second statistical modeling technique, we use the Andersen-Darling goodness-of-fit method on systematic partitions of the data. This second method evaluates a model by how well it passes the normality test on the data. Both of our statistical models summarize the data so as to answer …
Date: February 22, 2002
Creator: Eliassi-Rad, T.; Critchlow, T. & Abdulla, G.
System: The UNT Digital Library
Integration and Evaluation of a Position Sensor with Continuous Read-Out for use with the Environmental Measurement-While-Drilling Gamma Ray Spectrometer System (open access)

Integration and Evaluation of a Position Sensor with Continuous Read-Out for use with the Environmental Measurement-While-Drilling Gamma Ray Spectrometer System

The Environmental Measurement-While-Drilling-Gamma Ray Spectrometer (EMWD-GRS) system represents an innovative blend of new and existing technology that provides real-time environmental and drill bit data during drilling operations. The EMWD-GRS technology was demonstrated at Savannah River Site (SRS) F-Area Retention Basin. The EMWD-GRS technology demonstration consisted of continuously monitoring for gamma-radiation-producing contamination while drilling two horizontal boreholes below the backfilled waste retention basin. These boreholes passed near previously sampled locations where concentrations of contaminant levels of cesium had been measured. Contaminant levels continuously recorded by the EMWD-GRS system during drilling were compared to contaminant levels previously determined through quantitative laboratory analysis of soil samples. The demonstration of the EMWD-GRS was a complete success. The results show general agreement between the soil sampling and EMWD-GRS techniques for CS-137. It was recognized that the EMWD-GRS tool would better satisfy our customers' needs if the instrument location could be continuously monitored. During the demonstration at SRS, an electromagnetic beacon with a walkover monitor (Subsite{reg_sign}) was used to measure bit location at depth. To use a beacon locator drilling must be stopped, thus it is normally only used when a new section of pipe was added. The location of contamination could only be estimated based …
Date: February 22, 1999
Creator: Lockwood, G. J.; Normann, R. A.; Selph, M. M. & Williams, C. V.
System: The UNT Digital Library
Design and Testing of Metal and Silicon Heat Spreaders with Embedded Micromachined Heat Pipes (open access)

Design and Testing of Metal and Silicon Heat Spreaders with Embedded Micromachined Heat Pipes

The authors have developed a new type of heat spreader based on the integration of heat pipes directly within a thin planar structure suitable for use as a heat spreader or as the base layer in a substrate. The process uses micromachining methods to produce micron scale patterns that act as a wick in these small scale heat pipes. By using silicon or a low expansion metal as the wall material of these spreaders, they achieve a good match to the thermal coefficient of expansion of the die. The match allows the use of a thin high performance die attachment even on large size die. The embedded heat pipes result in high effective thermal conductivity for the new spreader technology.
Date: February 22, 1999
Creator: Benson, D. A. & Robino, C. V.
System: The UNT Digital Library
WIPP Waste Characterization: Implementing Regulatory Requirements in the Real World (open access)

WIPP Waste Characterization: Implementing Regulatory Requirements in the Real World

It is imperative to ensure compliance of the Waste Isolation Pilot Project (WIPP) with applicable statutory and regulatory requirements. In particular, compliance with the waste characterization requirements of the Resource Conservation and Recovery Act (RCRA) and its implementing regulation found at 40 CFR Parts 262,264 and 265 for hazardous and mixed wastes, as well as those of the Atomic Energy Act of 1954, as amended, the Reorganization Plan No. 3 of 1970, the Nuclear Waste Policy Act of 1982, as amended, and the WIPP Land Withdrawal Act, as amended, and their implementing regulations found at 40 CFR Parts 191 and 194 for non-mixed radioactive wastes, are often difficult to ensure at the operational level. For example, where a regulation may limit a waste to a certain concentration, this concentration may be difficult to measure. For example, does the definition of transuranic waste (TRU) as 100 nCi/grain of alpha-emitting transuranic isotopes per gram of waste mean that the radioassay of a waste must show a reading of 100 plus the sampling and measurement error for the waste to be a TRU waste? Although the use of acceptable knowledge to characterize waste is authorized by statute, regulation and DOE Orders, its implementation …
Date: February 22, 1999
Creator: Cooper Wayman, J.D. & Goldstein, J.D.
System: The UNT Digital Library
Solder Contamination (open access)

Solder Contamination

There are two sources of contamination in solder alloys. The first source is trace elements from the primary metals used in the as-manufactured product, be that product in ingot, wire, or powder form. Their levels in the primary metal are determined by the refining process. While some of these trace elements are naturally occurring materials, additional contamination can result from the refining and/or forming processes. Sources include: furnace pot liners, debris on the cutting edges of shears, rolling mill rollers, etc. The types and levels of contaminants per solder alloy are set by recognized industrial, federal, military, and international specifications. For example, the 63Sn-37Pb solder purchased to the ASTM B 32 standard can have maximum levels of contamination for the following metals: 0.08(wt.)%Cu, 0.001 %Cd, 0.005%Al, 0.25%Bi, 0.03%As, 0.02%Fe, and 0.005 %Zn. A second cause of contamination in solders, and solder baths in particular, is their actual use in soldering operations. Each time a workpiece is introduced into the bath, some dissolution of the joint base metal(s), protective or solderable coatings, and fixture metal takes place which adds to contamination levels in the solder. The potential impurities include Cu; Ni; Au or other noble metals used as protective finishes and …
Date: February 22, 1999
Creator: Vianco, P. T.
System: The UNT Digital Library
Environmental Measurement While Drilling System for Real-Time Field Screening of Contaminants (open access)

Environmental Measurement While Drilling System for Real-Time Field Screening of Contaminants

Sampling during environmental drilling is essential to fully characterize the spatial distribution and migration of subsurface contaminants. However, analysis of the samples is expensive and time-consuming: off-site laboratory analysis can take weeks or months. Real-time information on environmental conditions, drill bit location and temperature during drilling is valuable in many environmental restoration operations. This type of information can be used to provide field screening data and improved efficiency of site characterization activities. The Environmental Measurement-While-Drilling (EMWD) System represents an innovative blending of new and existing technology in order to obtain real-time data during drilling. The system consists of two subsystems. The down-hole subsystem (at the drill bit) consists of sensors, a power supply, a signal conditioning and transmitter board, and a radio-frequency (RF) coaxial cable. The up-hole subsystem consists of a battery pack/coil, pickup coil, receiver, and personal computer. The system is compatible with fluid miser drill pipe, a directional drilling technique that uses minimal drilling fluids and generates little to no secondary waste. In EMWD, downhole sensors are located behind the drill bit and linked by a high-speed data transmission system to a computer at the surface. Sandia-developed Windows{trademark}-based software is used for data display and storage. As drilling …
Date: February 22, 1999
Creator: Lockwood, G. J.; Normann, R. A. & Williams, C. V.
System: The UNT Digital Library
A Parametric Analysis of Solidification in Y(Fe,Ni,Cr)-Nb-C Alloys (open access)

A Parametric Analysis of Solidification in Y(Fe,Ni,Cr)-Nb-C Alloys

A parametric analysis is presented which summarizes the amount of total ({gamma}/NbC + {gamma}/Laves) and individual {gamma}/NbC and {gamma}/Laves constituents which form during solidification of {gamma}{sub (Fe,Ni,Cr)} alloys with variations in nominal Nb and C contents. Calculated results are presented for Fe base alloys and Ni base alloys. The results provide a quantitative rationale for understanding the relation between alloy composition and solidification microstructures and should provide useful insight into commercial alloys of similar composition.
Date: February 22, 1999
Creator: DuPont, J. N. & Robino, C. V.
System: The UNT Digital Library
The Design Process of Physical Security as Applied to a U.S. Border Port of Entry (open access)

The Design Process of Physical Security as Applied to a U.S. Border Port of Entry

This paper details the application of a standard physical security system design process to a US Border Port of Entry (PoE) for vehicle entry/exit. The physical security design methodology is described as well as the physical security similarities to facilities currently at a US Border PoE for vehicles. The physical security design process description includes the various elements that make up the methodologies well as the considerations that must be taken into account when dealing with system integration of those elements. The distinctions between preventing unlawful entry/exit of illegal contraband and personnel are described. The potential to enhance the functions of drug/contraband detection in the Pre-Primary Inspection area through the application of emerging technologies are also addressed.
Date: February 22, 1999
Creator: Wagner, G.G.
System: The UNT Digital Library
Environmental Measurement-While-Drilling System for Real-Time Field Screening of Contaminants (open access)

Environmental Measurement-While-Drilling System for Real-Time Field Screening of Contaminants

Sampling during environmental drilling is essential to fully characterize the spatial distribution and migration of near surface contaminants. However, analysis of the samples is expensive and time-consuming: off-site laboratory analysis can take weeks or months. An alternative screening technology, Environmental Measurement-While-Drilling (EMWD), could save money and valuable time by quickly distinguishing between contaminated and uncontaminated areas. Real time measurements provided by an EMWD system enable on-the-spot decisions to be made regarding sampling strategies. The system also enhances worker safety and provides the added flexibility of being able to steer a drill bit in or out of hazardous zones.
Date: February 22, 1999
Creator: Bishop, L. B.; Lockwood, G. J.; Normann, R. A.; Selph, M. M. & Williams, C. V.
System: The UNT Digital Library
Dissipated power measurements in the A0 SRF cavity system (open access)

Dissipated power measurements in the A0 SRF cavity system

Fermilab operates a single TESLA 9-cell superconducting RF cavity in support of a photoelectron R and D beam line. Power going into the 1.8K cryogenic system via static heat leak and RF dissipation is measured from the rate of rise of the pressure in the helium bath. This paper describes the techniques used to determine the cryostat heat load and the RF performance of the cavity. A photo-injector has been constructed at Fermilab to produce a low-energy (14--18 MeV) electron beam with high charge per bunch (8 nC), short bunch length (1 mm RMS), and small transverse emittance (<20 mm mrad). The facility was used to commission a photo-cathode RF gun for the TESLA Test Facility (TTF) Linac at DESY. At present, the Fermilab machine is being used for R and D in bunch length compression and fast beam diagnostics; experiments in plasma wake field acceleration and channeling acceleration are in preparation.
Date: February 22, 2000
Creator: Fuerst, J. D. & Hartung, W. H.
System: The UNT Digital Library
Dynamic Impact Analysis of Bagless Transfer System 3013 Can in Drops at Various Inclination Angles (open access)

Dynamic Impact Analysis of Bagless Transfer System 3013 Can in Drops at Various Inclination Angles

The purpose of this analysis is to provide rational judgment for the most pernicious impact angle of dropping. A numerical simulation method, finite element analysis, is adopted for this study. The general-purpose finite element analysis code, ABAQUS(R) [HKS, 1998], facilitates the numerical computation. The geometrical finite element modeling is developed with the software PATRAN(R) [MSC, 1999]. The finite element code ABAQUS(R)has been verified according to the QA plans.
Date: February 22, 2001
Creator: Gong, C.
System: The UNT Digital Library
Method for Sampling Alpha-Helical Protein Backbones (open access)

Method for Sampling Alpha-Helical Protein Backbones

We present a novel technique of sampling the configurations of helical proteins. Assuming knowledge of native secondary structure, we employ assembly rules gathered from a database of existing structures to enumerate the geometrically possible 3-D arrangements of the constituent helices. We produce a library of possible folds for 25 helical protein cores. In each case the method finds significant numbers of conformations close to the native structure. In addition we assign coordinates to all atoms for 4 of the 25 proteins. In the context of database driven exhaustive enumeration our method performs extremely well, yielding significant percentages of structures (0.02%--82%) within 6A of the native structure. The method's speed and efficiency make it a valuable contribution towards the goal of predicting protein structure.
Date: February 22, 2000
Creator: Fain, Boris & Levitt, Michael
System: The UNT Digital Library
Shortest Path Planning for a Tethered Robot or an Anchored Cable (open access)

Shortest Path Planning for a Tethered Robot or an Anchored Cable

We consider the problem of planning shortest paths for a tethered robot with a finite length tether in a 2D environment with polygonal obstacles. We present an algorithm that runs in time O((k{sub 1} + 1){sup 2}n{sup 4}) and finds the shortest path or correctly determines that none exists that obeys the constraints; here n is the number obstacle vertices, and k{sub 1} is the number loops in the initial configuration of the tether. The robot may cross its tether but nothing can cross obstacles, which cause the tether to bend. The algorithm applies as well for planning a shortest path for the free end of an anchored cable.
Date: February 22, 1999
Creator: Xavier, P.G.
System: The UNT Digital Library
A note on simulation and dynamical hierarchies (open access)

A note on simulation and dynamical hierarchies

This paper summarizes some of the problems associated with the generation of higher order emergent structures in formal dynamical systems as well as some of the formal properties of dynamical systems capable of generating higher order structures.
Date: February 22, 1996
Creator: Rasmussen, S.; Barrett, C. L.; Baas, N. A. & Olesen, M. W.
System: The UNT Digital Library