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Danger of General Spread of the Gypsy and Browntail Moths Through Imported Nursery Stock

Danger of General Spread of the Gypsy and Browntail Moths Through Imported Nursery Stock

Date: 1911
Creator: Marlatt, C. L.
Description: "This paper gives a record of the infested importations [of brown-tail and gypsy moths] during the last two years and descriptions of nursery conditions in Europe, showing the nature of the infestation there, and concludes with a brief description, with illustrations, of the two moth pests which are now being thus imported. The publication is, therefore, a warning to users of such imported stock and gives descriptions and figures enabling the prompt recognition of either of these pests wherever they may become established." -- p. 2
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Danger of ice formation on airplanes

Danger of ice formation on airplanes

Date: February 1, 1929
Creator: Kopp, W
Description: This paper relates the different types of ice formations that can occur on airplanes and the dangers that they pose.
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The danger of stalled flight and an analysis of the factors which govern it

The danger of stalled flight and an analysis of the factors which govern it

Date: November 1, 1921
Creator: Hopf, L
Description: A definition of "stalled fight" is presented as well as a detailed discussion on the how and why it occurs. Some suggestions are made to prevent its occurrence such as carrying an air speed instrument in the airplane.
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The dangerous flat spin and the factors affecting it

The dangerous flat spin and the factors affecting it

Date: July 1, 1931
Creator: Fuchs, Richard & Schmidt, Wilhelm
Description: This report deals first with the fundamental data required for the investigation. These are chiefly the aerodynamic forces and moments acting on an airplane in a flat spin. It is shown that these forces and moments depend principally on the angle of attack and on the rotation about the path axis, and can therefore either be measured in a wind tunnel or calculated from wind-tunnel measurements of lift, drag and moment about the leading edge of the wing of an airplane model at rest. The lift, drag and moments about the span axis are so greatly altered by the rapid rotation in a flat spin, that they can no longer be regarded as independent of rotation. No substantial change in the angles of attack and glide occurring in a flat spin is involved. The cross-wind force, as compared with the lift and drag, can be disregarded in a flat spin.
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A dangerous seaplane landing condition

A dangerous seaplane landing condition

Date: May 1, 1928
Creator: Carroll, Thomas
Description: A peculiar phenomena in seaplane landing is observed and reported. The seaplane having executed a normal fast landing at low incidence, a forward movement of the control stick effected an unusual condition in that the seaplane left the water suddenly in an abnormal attitude. The observations describing this phenomena are offered as a warning against possible accident and as a conjectural cause of seaplane landing accidents of a certain kind.
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The dangerous sideslip of a stalled airplane and its prevention

The dangerous sideslip of a stalled airplane and its prevention

Date: September 1, 1931
Creator: Schmidt, Wilhelm & Fuchs, Richard
Description: This investigation covers only that phase of airplane accidents which are the result of sideslip. We examine the circumstances under which this occurs, study the behavior of present-day airplane types (monoplane, conventional and staggered biplane) therein and endeavor to find a solution whereby this danger may be avoided.
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The dangers of heterogeneous network computing: heterogeneous networks considered harmful

The dangers of heterogeneous network computing: heterogeneous networks considered harmful

Date: December 31, 1996
Creator: Demmel, J.; Stanley, K.; Dongarra, J.; Hammarling, S. & Osstrouchov, S.
Description: This report addresses the issue of writing reliable numerical software for networks of heterogeneous computers. Much software has been written for distributed memory parallel computers and in principal such software could readily be ported to networks of machines, such as a collection of workstations connected by Ethernet, but if such a network is not homogeneous there are special challenges that need to be addressed. The symptoms can range from erroneous results returned without warning to deadlock. Some of the problems are straightforward to solve, but for others the solutions are not so obvious and indeed in some cases, such as the method of bisection which we shall discuss in the report, we have not yet decided upon a satisfactory solution that does not incur an unacceptable overhead. Making software robust on heterogeneous systems often requires additional communication. In this report we describe and illustrate the problems and, where possible, suggest solutions so that others may be aware of the potential pitfalls and either avoid them or, if that is not possible, ensure that their software is not used on heterogeneous networks.
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DANSCE: A 4PIBARIUM FLUORIDE DETECTOR FOR MEASURING NEUTRON CAPTURE ON UNSTABLE NUCLEAI.

DANSCE: A 4PIBARIUM FLUORIDE DETECTOR FOR MEASURING NEUTRON CAPTURE ON UNSTABLE NUCLEAI.

Date: September 19, 2002
Creator: ULLMAN, JL; HAIGHT, RC, HUNT, LF; REIFARTH, R; BREDEWEG, TA; MILLER, GG; WILHELMY, JB et al.
Description: No abstract prepared.
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The DANTE Boltzmann transport solver: An unstructured mesh, 3-D, spherical harmonics algorithm compatible with parallel computer architectures

The DANTE Boltzmann transport solver: An unstructured mesh, 3-D, spherical harmonics algorithm compatible with parallel computer architectures

Date: June 1, 1997
Creator: McGhee, J.M.; Roberts, R.M. & Morel, J.E.
Description: A spherical harmonics research code (DANTE) has been developed which is compatible with parallel computer architectures. DANTE provides 3-D, multi-material, deterministic, transport capabilities using an arbitrary finite element mesh. The linearized Boltzmann transport equation is solved in a second order self-adjoint form utilizing a Galerkin finite element spatial differencing scheme. The core solver utilizes a preconditioned conjugate gradient algorithm. Other distinguishing features of the code include options for discrete-ordinates and simplified spherical harmonics angular differencing, an exact Marshak boundary treatment for arbitrarily oriented boundary faces, in-line matrix construction techniques to minimize memory consumption, and an effective diffusion based preconditioner for scattering dominated problems. Algorithm efficiency is demonstrated for a massively parallel SIMD architecture (CM-5), and compatibility with MPP multiprocessor platforms or workstation clusters is anticipated.
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DANTSYS: A diffusion accelerated neutral particle transport code system

DANTSYS: A diffusion accelerated neutral particle transport code system

Date: June 1, 1995
Creator: Alcouffe, R.E.; Baker, R.S.; Brinkley, F.W.; Marr, D.R.; O`Dell, R.D. & Walters, W.F.
Description: The DANTSYS code package includes the following transport codes: ONEDANT, TWODANT, TWODANT/GQ, TWOHEX, and THREEDANT. The DANTSYS code package is a modular computer program package designed to solve the time-independent, multigroup discrete ordinates form of the boltzmann transport equation in several different geometries. The modular construction of the package separates the input processing, the transport equation solving, and the post processing (or edit) functions into distinct code modules: the Input Module, one or more Solver Modules, and the Edit Module, respectively. The Input and Edit Modules are very general in nature and are common to all the Solver Modules. The ONEDANT Solver Module contains a one-dimensional (slab, cylinder, and sphere), time-independent transport equation solver using the standard diamond-differencing method for space/angle discretization. Also included in the package are solver Modules named TWODANT, TWODANT/GQ, THREEDANT, and TWOHEX. The TWODANT Solver Module solves the time-independent two-dimensional transport equation using the diamond-differencing method for space/angle discretization. The authors have also introduced an adaptive weighted diamond differencing (AWDD) method for the spatial and angular discretization into TWODANT as an option. The TWOHEX Solver Module solves the time-independent two-dimensional transport equation on an equilateral triangle spatial mesh. The THREEDANT Solver Module solves the time independent, ...
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DANTSYS: a system for deterministic, neutral particle transport calculations

DANTSYS: a system for deterministic, neutral particle transport calculations

Date: December 31, 1996
Creator: Alcouffe, R.E. & Baker, R.S.
Description: The THREEDANT code is the latest addition to our system of codes, DANTSYS, which perform neutral particle transport computations on a given system of interest. The system of codes is distinguished by geometrical or symmetry considerations. For example, ONEDANT and TWODANT are designed for one and two dimensional geometries respectively. We have TWOHEX for hexagonal geometries, TWODANT/GQ for arbitrary quadrilaterals in XY and RZ geometry, and THREEDANT for three-dimensional geometries. The design of this system of codes is such that they share the same input and edit module and hence the input and output is uniform for all the codes (with the obvious additions needed to specify each type of geometry). The codes in this system are also designed to be general purpose solving both eigenvalue and source driven problems. In this paper we concentrate on the THREEDANT module since there are special considerations that need to be taken into account when designing such a module. The main issues that need to be addressed in a three-dimensional transport solver are those of the computational time needed to solve a problem and the amount of storage needed to accomplish that solution. Of course both these issues are directly related to the ...
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DANTSYS/MPI: a system for 3-D deterministic transport on parallel architectures

DANTSYS/MPI: a system for 3-D deterministic transport on parallel architectures

Date: December 31, 1996
Creator: Baker, R.S. & Alcouffe, R.E.
Description: Since 1994, we have been using a data parallel form of our deterministic transport code DANTSYS to perform time-independent fixed source and eigenvalue calculations on the CM-200`s at Los Alamos National Laboratory (LANL). Parallelization of the transport sweep is obtained by using a 2-D spatial decomposition which retains the ability to invert the source iteration equation in a single iteration (i.e., the diagonal plane sweep). We have now implemented a message passing version of DANTSYS, referred to as DANTSYS/MPI, on the Cray T3D installed at Los Alamos in 1995. By taking advantage of the SPMD (Single Program, Multiple Data) architecture of the Cray T3D, as well as its low latency communications network, we have managed to achieve grind times (time to solve a single cell in phase space) of less than 10 nanoseconds on the 512 PE (Processing Element) T3D, as opposed to typical grind times of 150-200 nanoseconds on a 2048 PE CM-200, or 300-400 nanoseconds on a single PE of a Cray Y-MP. In addition, we have also parallelized the Diffusion Synthetic Accelerator (DSA) equations which are used to accelerate the convergence of the transport equation. DANTSYS/MPI currently runs on traditional Cray PVP`s and the Cray T3D, and ...
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DAPHNE Operation And Plans for DAPHNE2

DAPHNE Operation And Plans for DAPHNE2

Date: January 20, 2006
Creator: Zobov, M.; Alesini, D.; Benedetti, G.; Biagini, M.E.; Biscari, C.; Boni, R. et al.
Description: The e{sup +}e{sup -} collider DA{Phi}NE, a 1.02 GeV c.m. {Phi}-factory, has reached a peak luminosity of about 1.4 x 10{sup 32} cm{sup -2} s{sup -1} and a peak integrated luminosity in one day of about 8.6 pb{sup -1}. With the current rates the physics program of the three main experiments DEAR, FINUDA and KLOE will be completed by the end of 2007. In this paper we describe in detail the steps which have led to the luminosity improvement and the options for the upgrade of the collider towards higher energy and/or luminosity.
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Darex Process: Processing of Stainless Steel-Containing Reactor Fuels with Dilute Aqua Regia

Darex Process: Processing of Stainless Steel-Containing Reactor Fuels with Dilute Aqua Regia

Date: June 7, 1962
Creator: Kitts, F. G.
Description: From abstract: "The Darex process developed for the recovery of uranium from stainless steel-containing reactor fuels consists of three steps: (1) dissolution of the fuel material in dilute aqua regia, (2) removal of chloride from the solution to prevent corrosion of downstream stainless steel process equipment, and (3) adjustment of the nitrate solution to solvent extraction feed conditions."
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Darfur Crisis: Death Estimates Demonstrates Severity of Crisis, but Their Accuracy and Credibility Could Be Enhanced

Darfur Crisis: Death Estimates Demonstrates Severity of Crisis, but Their Accuracy and Credibility Could Be Enhanced

Date: November 9, 2006
Creator: United States. Government Accountability Office.
Description: A letter report issued by the Government Accountability Office with an abstract that begins "In 2003, violent conflict in Darfur, Sudan, broke out between rebel groups and government troops and government-supported Arab militias. While few would dispute that many thousands of Darfur civilians have died, less consensus exists about the total number of deaths attributable to the crisis. Estimates by the Department of State (State) and other parties report death tolls up to about 400,000 for varying populations and periods of time between February 2003 and August 2005. Based on the views of experts convened by GAO and the National Academy of Sciences, interviews with estimate authors, and a review of relevant literature, this report (1) evaluates six Darfur death estimates, (2) identifies general challenges to estimating deaths in such crises, and (3) discusses measures to improve death estimates."
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Darfur Crisis: Progress in Aid and Peace Monitoring Threatened by Ongoing Violence and Operational Challenges

Darfur Crisis: Progress in Aid and Peace Monitoring Threatened by Ongoing Violence and Operational Challenges

Date: November 9, 2006
Creator: United States. Government Accountability Office.
Description: A letter report issued by the Government Accountability Office with an abstract that begins "In 2003, violent conflict in Darfur, Sudan broke out between rebel groups, government troops, and government-supported Arab militias, known as the Janjaweed. The conflict has displaced about 2 million Darfurians and has so affected over 1.9 million others that they require assistance. Since October 2003, the U.S. government has provided humanitarian assistance in Darfur and supported African Union Mission in Sudan's (AMIS) efforts to fulfill a peace support mandate. This report reviews (1) U.S. humanitarian assistance provided to Darfur and the challenges that have been encountered and (2) African Union efforts to fulfill its mandate and challenges that have affected these efforts."
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DARHT 2 kA Cathode Development

DARHT 2 kA Cathode Development

Date: March 9, 2009
Creator: Henestroza, E.; Houck, T.; Kwan, J.W.; Leitner, M.; Miram, G.; Prichard, B. et al.
Description: In the campaign to achieve 2 kA of electron beam current, we have made several changes to the DARHT-II injector during 2006-2007. These changes resulted in a significant increase in the beam current, achieving the 2 kA milestone. Until recently (before 2007), the maximum beam current that was produced from the 6.5-inch diameter (612M) cathode was about 1300 A when the cathode was operating at a maximum temperature of 1140 C. At this temperature level, the heat loss was dominated by radiation which is proportional to temperature to the fourth power. The maximum operating temperature was limited by the damage threshold of the potted filament and the capacity of the filament heater power supply, as well as the shortening of the cathode life time. There were also signs of overheating at other components in the cathode assembly. Thus it was clear that our approach to increase beam current could not be simply trying to run at a higher temperature and the preferred way was to operate with a cathode that has a lower work function. The dispenser cathode initially used was the type 612M made by SpectraMat. According to the manufacturer's bulletin, this cathode should be able to produce more ...
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DARHT - an `adequate` EIS: A NEPA case study

DARHT - an `adequate` EIS: A NEPA case study

Date: August 1, 1997
Creator: Webb, M.D.
Description: The Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility Environmental Impact Statement (EIS) provides a case study that is interesting for many reasons. The EIS was prepared quickly, in the face of a lawsuit, for a project with unforeseen environmental impacts, for a facility that was deemed urgently essential to national security. Following judicial review the EIS was deemed to be {open_quotes}adequate.{close_quotes} DARHT is a facility now being built at Los Alamos National Laboratory (LANL) as part of the Department of Energy (DOE) nuclear weapons stockpile stewardship program. DARHT will be used to evaluate the safety and reliability of nuclear weapons, evaluate conventional munitions and study high-velocity impact phenomena. DARHT will be equipped with two accelerator-driven, high-intensity X-ray machines to record images of materials driven by high explosives. DARHT will be used for a variety of hydrodynamic tests, and DOE plans to conduct some dynamic experiments using plutonium at DARHT as well.
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The DARHT-II-DC Final Focus Solenoid

The DARHT-II-DC Final Focus Solenoid

Date: March 6, 2000
Creator: Paul, A.C.
Description: The baseline DARHT2 external beam uses a pulsed solenoid final focus lens. The design of this lens was presented at TOS2 and has been considered as the final focus lens in all of the Livermore beamlines for DARHT2. In this note, we consider a new alternative DC final focus solenoid. A crude comparison between the parameters of these two designs is given in table 1. The small spot size required by the radiography and the small drift distance available between the last magnetic focusing element and the final focus solenoid imposed by the close proximity between the DARHT 2 building and the DARHT 1 axis, implies a short focal length solenoid. This in turn requires that the final focus solenoid mount inside the re-entrant cavity of the containment vessel in order to accommodate the 0.9 meter conjugate: figure 1. The ID of this cavity is 13.88 inches (35.25 cm).
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DARHT-II Injector Transients and the Ferrite Damper

DARHT-II Injector Transients and the Ferrite Damper

Date: August 4, 2006
Creator: Waldron, Will; Reginato, Lou; Chow, Ken; Houck, Tim; Henestroza, Enrique; Yu, Simon et al.
Description: This report summarizes the transient response of the DARHT-II Injector and the design of the ferrite damper. Initial commissioning of the injector revealed a rise time excited 7.8 MHz oscillation on the diode voltage and stalk current leading to a 7.8 MHz modulation of the beam current, position, and energy. Commissioning also revealed that the use of the crowbar to decrease the voltage fall time excited a spectrum of radio frequency modes which caused concern that there might be significant transient RF electric field stresses imposed on the high voltage column insulators. Based on the experience of damping the induction cell RF modes with ferrite, the concept of a ferrite damper was developed to address the crowbar-excited oscillations as well as the rise-time-excited 7.8 MHz oscillations. After the Project decided to discontinue the use of the crowbar, further development of the concept focused exclusively on damping the oscillations excited by the rise time. The design was completed and the ferrite damper was installed in the DARHT-II Injector in February 2006. The organization of this report is as follows. The suite of injector diagnostics are described in Section 2. The data and modeling of the injector transients excited on the rise-time ...
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DARHT II Scaled Accelerator Tests on the ETA II Accelerator*

DARHT II Scaled Accelerator Tests on the ETA II Accelerator*

Date: May 26, 2005
Creator: Weir, J T; Anaya Jr, E M; Caporaso, G J; Chambers, F W; Chen, Y; Falabella, S et al.
Description: The DARHT II accelerator at LANL is preparing a series of preliminary tests at the reduced voltage of 7.8 MeV. The transport hardware between the end of the accelerator and the final target magnet was shipped to LLNL and installed on ETA II. Using the ETA II beam at 5.2 MeV we completed a set of experiments designed reduce start up time on the DARHT II experiments and run the equipment in a configuration adapted to the reduced energy. Results of the beam transport using a reduced energy beam, including the kicker and kicker pulser system will be presented.
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DARHT: INTEGRATION OF AUTHORIZATION BASIS REQUIREMENTS AND WORKER SAFETY

DARHT: INTEGRATION OF AUTHORIZATION BASIS REQUIREMENTS AND WORKER SAFETY

Date: April 2001
Creator: McClure, Donald A.; Nelson, Christine A. & Boudrie, Richard L.
Description: This document describes the results of consensus agreements reached by the DARHT Safety Planning Team during the development of the update of the DARHT Safety Analysis Document (SAD). The SAD is one of the Authorization Basis (AB) Documents required by the Department prior to granting approval to operate the DARHT Facility. The DARHT Safety Planning Team is lead by Mr. Joel A. Baca of the Department of Energy Albuquerque Operations Office (DOE/AL). Team membership is drawn from the Department of Energy Albuquerque Operations Office, the Department of Energy Los Alamos Area Office (DOE/LAAO), and several divisions of the Los Alamos National Laboratory. Revision 1 of the DARHT SAD had been written as part of the process for gaining approval to operate the Phase 1 (First Axis) Accelerator. Early in the planning stage for the required update of the SAD for the approval to operate both Phase 1 and Phase 2 (First Axis and Second Axis) DARHT Accelerator, it was discovered that a conflict existed between the Laboratory approach to describing the management of facility and worker safety.
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DARHT : integration of shielding design and analysis with facility design /

DARHT : integration of shielding design and analysis with facility design /

Date: January 1, 2002
Creator: Boudrie, R. L. (Richard L.); Brown, T. H. (Thomas H.); Gilmore, W. E. (Walter E.); Downing, J. N. (James N.), Jr.; Hack, Alan; McClure, D. A. (Donald A.) et al.
Description: The design of the interior portions of the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility incorporated shielding and controls from the beginning of the installation of the Accelerators. The purpose of the design and analysis was to demonstrate the adequacy of shielding or to determine the need for additional shielding or controls. Two classes of events were considered: (1) routine operation defined as the annual production of 10,000 2000-ns pulses of electrons at a nominal energy of 20 MeV, some of which are converted to the x-ray imaging beam consisting of four nominal 60-ns pulses over the 2000-ns time frame, and (2) accident case defined as up to 100 2000-ns pulses of electrons accidentally impinging on some metallic surface, thereby producing x rays. Several locations for both classes of events were considered inside and outside of the accelerator hall buildings. The analysis method consisted of the definition of a source term for each case studied and the definition of a model of the shielding and equipment present between the source and the dose areas. A minimal model of the fixed existing or proposed shielding and equipment structures was used for a first approximation. If the resulting dose from the first ...
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The DARHT Scattering Wire Spectrometer: Operation and Checkout on ETA II

The DARHT Scattering Wire Spectrometer: Operation and Checkout on ETA II

Date: March 9, 2005
Creator: Fessenden, T J
Description: The DARHT Scattering wire energy spectrometer has been realized and checked out on ETA II. The ETA II beam energy is generally around 5.3 MeV. This value varies from pulse-to-pulse by around 0.5% and from month-to-month by as much as 6%. The energy acceptance of the spectrometer is {+-} 5% and the time response is less than 10 ns. The instrument was calibrated to enable absolute measurements of the ETA II beam energy accurate to {+-}3%. The beam energy in MeV is related to the bending magnetic field B{sub kG} according to E{sub MeV} = 0.511[{radical}(1+347.2B{sub kG}{sup 2}) -1]. The major difficulty encountered was in the development of detectors for the scattered electrons passing through the instrument. Fortunately one detector was fabricated that worked satisfactorily which enabled us to complete the tests on ETA II. The ETA II experiments and initial FXR experiments suggest that spurious X-ray signals will not prove troublesome. No results are yet available in the x-ray environment of DARHT.
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