Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.

This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). Themore » goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.« less

Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Thomas Martin; Celik, Cihangir; Isbell, Kimberly McMahan

This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). Themore » goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.« less

ENDF/B-VII.0 Data Testing Using 1,172 Critical Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plechaty, E F; Cullen, D E

2007-10-01

In order to test the ENDF/B-VII.0 neutron data library [1], 1,172 critical assemblies from [2] have been calculated using the Monte Carlo transport code TART [3]. TART's 'best' physics was used for all of these calculations; this included continuous energy cross sections, delayed neutrons in their spectrum that is slower than prompt neutrons, unresolved resonance region self-shielding, the thermal scattering (free atom for all materials plus thermal scattering law data S({alpha},{beta}) when available). In this first pass through the assemblies the objective was to 'quickly' test the validity of the ENDF/B-VII.0 data [1], the assembly models as defined in [2]more » and coded for use with TART, and TART's physics treatment [3] of these assemblies. With TART we have the option of running criticality problems until K-eff has been calculated to an acceptable input accuracy. In order to 'quickly' calculate all of these assemblies K-eff was calculated in each case to +/- 0.002. For these calculations the assemblies were divided into ten types based on fuel (mixed, Pu239, U233, U235) and median fission energy (Fast, Midi, Slow). A table is provided that shows a summary of these results. This is followed be details for every assembly, and statistical information about the distribution of K-eff for each type of assembly. After a review of these results to eliminate any obvious errors in ENDF/B data, assembly models, or TART physics, all assemblies will be run again to a higher precision. Only after this second run is finished will we have highly precise results. Until then the results presently here should only be interpreted as approximate values of K-eff with a standard deviation of +/- 0.002; for such a large number of assemblies we expected the results to be approximately normal, with a spread out to several times the standard deviation; see the calculated statistical distributions and their comparisons to a normal distribution.« less

Los Alamos Climatology 2016 Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruggeman, David Alan

The Los Alamos National Laboratory (LANL or the Laboratory) operates a meteorology monitoring network to support LANL emergency response, engineering designs, environmental compliance, environmental assessments, safety evaluations, weather forecasting, environmental monitoring, research programs, and environmental restoration. Weather data has been collected in Los Alamos since 1910. Bowen (1990) provided climate statistics (temperature and precipitation) for the 1961– 1990 averaging period, and included other analyses (e.g., wind and relative humidity) based on the available station locations and time periods. This report provides an update to the 1990 publication Los Alamos Climatology (Bowen 1990).

Los Alamos offers Fellowships

NASA Astrophysics Data System (ADS)

Los Alamos National Laboratory in New Mexico is calling for applications for postdoctoral appointments and research fellowships. The positions are available in geoscience as well as other scientific disciplines.The laboratory, which is operated by the University of California for the Department of Energy, awards J. Robert Oppenheimer Research Fellowships to scientists that either have or will soon complete doctoral degrees. The appointments are for two years, are renewable for a third year, and carry a stipend of $51,865 per year. Potential applicants should send a resume or employment application and a statement of research goals to Carol M. Rich, Div. 89, Human Resources Development Division, MS P290, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 by mid-November.

Los Alamos National Lab: National Security Science

Science.gov Websites

SKIP TO PAGE CONTENT Los Alamos National Laboratory Delivering science and technology to protect Permit for Storm Water Public Reading Room Environment Home News Los Alamos National Lab: National deposition operations for the Center for Integrated Nanotechnologies at Los Alamos. Innovation drives his

Water Supply at Los Alamos 1998-2001

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard J. Koch; David B. Rogers

2003-03-01

For the period 1998 through 2001, the total water used at Los Alamos from all sources ranged from 1325 million gallons (Mg) in 1999 to 1515 Mg in 2000. Groundwater production ranged from 1323 Mg in 1999 to 1506 Mg in 2000 from the Guaje, Pajarito, and Otowi fields. Nonpotable surface water used from Los Alamos reservoir ranged from zero gallons in 2001 to 9.3 Mg in 2000. For years 1998 through 2001, over 99% of all water used at Los Alamos was groundwater. Water use by Los Alamos National Laboratory (LANL) between 1998 and 2001 ranged from 379 Mgmore » in 2000 to 461 Mg in 1998. The LANL water use in 2001 was 393 Mg or 27% of the total water use at Los Alamos. Water use by Los Alamos County ranged from 872 Mg in 1999 to 1137 Mg in 2000, and averaged 1006 Mg/yr. Four new replacement wells in the Guaje field (G-2A, G-3A, G-4A, and G-5A) were drilled in 1998 and began production in 1999; with existing well G-1A, the Guaje field currently has five producing wells. Five of the old Guaje wells (G-1, G-2, G-4, G-5, and G-6) were plugged and abandoned in 1999, and one well (G-3) was abandoned but remains as an observation well for the Guaje field. The long-term water level observations in production and observation (test) wells at Los Alamos are consistent with the formation of a cone of depression in response to water production. The water level decline is gradual and at most has been about 0.7 to 2 ft per year for production wells and from 0.4 to 0.9 ft/yr for observation (test) wells. The largest water level declines have been in the Guaje field where nonpumping water levels were about 91 ft lower in 2001 than in 1951. The initial water levels of the Guaje replacement wells were 32 to 57 ft lower than the initial water levels of adjacent original Guaje wells. When production wells are taken off-line for pump replacement or repair, water levels have returned to within about 25 ft of initial static levels within 6 to 12 months. Thus, the water-level trends suggest no

Benchmarking of HEU Mental Annuli Critical Assemblies with Internally Reflected Graphite Cylinder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xiaobo, Liu; Bess, John D.; Marshall, Margaret A.

Three experimental configurations of critical assemblies, performed in 1963 at the Oak Ridge Critical Experiment Facility, which are assembled using three different diameter HEU annuli (15-9 inches, 15-7 inches and 13-7 inches) metal annuli with internally reflected graphite cylinder are evaluated and benchmarked. The experimental uncertainties which are 0.00055, 0.00055 and 0.00055 respectively, and biases to the detailed benchmark models which are -0.00179, -0.00189 and -0.00114 respectively, were determined, and the experimental benchmark keff results were obtained for both detailed and simplified model. The calculation results for both detailed and simplified models using MCNP6-1.0 and ENDF VII.1 agree well tomore » the benchmark experimental results with a difference of less than 0.2%. These are acceptable benchmark experiments for inclusion in the ICSBEP Handbook.« less

Tiger Team Assessment of the Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-11-01

The purpose of the safety and health assessment was to determine the effectiveness of representative safety and health programs at the Los Alamos National Laboratory (LANL). Within the safety and health programs at LANL, performance was assessed in the following technical areas: Organization and Administration, Quality Verification, Operations, Maintenance, Training and Certification, Auxiliary Systems, Emergency Preparedness, Technical Support, Packaging and Transportation, Nuclear Criticality Safety, Security/Safety Interface, Experimental Activities, Site/Facility Safety Review, Radiological Protection, Personnel Protection, Worker Safety and Health (OSHA) Compliance, Fire Protection, Aviation Safety, Explosives Safety, Natural Phenomena, and Medical Services.

Keeping the Momentum and Nuclear Forensics at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steiner, Robert Ernest; Dion, Heather M.; Dry, Donald E.

LANL has 70 years of experience in nuclear forensics and supports the community through a wide variety of efforts and leveraged capabilities: Expanding the understanding of nuclear forensics, providing training on nuclear forensics methods, and developing bilateral relationships to expand our understanding of nuclear forensic science. LANL remains highly supportive of several key organizations tasked with carrying forth the Nuclear Security Summit messages: IAEA, GICNT, and INTERPOL. Analytical chemistry measurements on plutonium and uranium matrices are critical to numerous programs including safeguards accountancy verification measurements. Los Alamos National Laboratory operates capable actinide analytical chemistry and material science laboratories suitable formore » nuclear material and environmental forensic characterization. Los Alamos National Laboratory uses numerous means to validate and independently verify that measurement data quality objectives are met. Numerous LANL nuclear facilities support the nuclear material handling, preparation, and analysis capabilities necessary to evaluate samples containing nearly any mass of an actinide (attogram to kilogram levels).« less

Los Alamos National Security, LLC Request for Information from industrial entities that desire to commercialize Laboratory-developed Extremely Low Resource Optical Identifier (ELROI) tech

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Michael Charles

Los Alamos National Security, LLC (LANS) is the manager and operator of the Los Alamos National Laboratory for the U.S. Department of Energy National Nuclear Security Administration under contract DE-AC52-06NA25396. LANS is a mission-centric Federally Funded Research and Development Center focused on solving the most critical national security challenges through science and engineering for both government and private customers.

Los Alamos Fires From Landsat 7

NASA Technical Reports Server (NTRS)

2002-01-01

On May 9, 2000, the Landsat 7 satellite acquired an image of the area around Los Alamos, New Mexico. The Landsat 7 satellite acquired this image from 427 miles in space through its sensor called the Enhanced Thematic Mapper Plus (ETM+). Evident within the imagery is a view of the ongoing Cerro Grande fire near the town of Los Alamos and the Los Alamos National Laboratory. Combining the high-resolution (30 meters per pixel in this scene) imaging capacity of ETM+ with its multi-spectral capabilities allows scientists to penetrate the smoke plume and see the structure of the fire on the surface. Notice the high-level of detail in the infrared image (bottom), in which burn scars are clearly distinguished from the hotter smoldering and flaming parts of the fire. Within this image pair several features are clearly visible, including the Cerro Grande fire and smoke plume, the town of Los Alamos, the Los Alamos National Laboratory and associated property, and Cerro Grande peak. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false color image where vegetation appears as bright to dark green (bottom image). Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. The areas recently burned appear black. Dark red to bright red patches, or linear features within the burned area, are the hottest and possibly actively burning areas of the fire. The fire is spreading downslope and the front of the fire is readily detectable about 2 kilometers to the west and south of Los Alamos. Combining ETM+ channels 3, 2, and 1 provides a true-color image of the greater Los Alamos region (top image). Vegetation is generally dark to medium green. Forested areas are very dark green

Internship at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunham, Ryan Q.

2012-07-11

Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. It provides support for our country's nuclear weapon stockpile as well as many other scientific research projects. I am an Undergraduate Student Intern in the Systems Design and Analysis group within the Nuclear Nonproliferation division of the Global Security directorate at LANL. I have been tasked with data analysis and modeling of particles in a fluidized bed system for the capture of carbon dioxide from power plant flue gas.

Publications of Los Alamos Research, 1983

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheridan, C.J.; McClary, W.J.; Rich, J.A.

1984-10-01

This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1983. Papers published in 1982 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted - even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was published more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers releasedmore » as non-Laboratory reports, journal articles, books, chapters of books, conference papers either published separately or as part of conference proceedings issued as books or reports, papers publishd in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.« less

Airport-Noise Levels and Annoyance Model (ALAMO) system's reference manual

NASA Technical Reports Server (NTRS)

Deloach, R.; Donaldson, J. L.; Johnson, M. J.

1986-01-01

The airport-noise levels and annoyance model (ALAMO) is described in terms of the constituent modules, the execution of ALAMO procedure files, necessary for system execution, and the source code documentation associated with code development at Langley Research Center. The modules constituting ALAMO are presented both in flow graph form, and through a description of the subroutines and functions that comprise them.

A Sailor in the Los Alamos Navy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Judd, D. L.; Meade, Roger Allen

As part of the War Department’s Manhattan Engineer District (MED), Los Alamos was an Army installation during World War II, complete with a base commander and a brace of MPs. But it was a unique Army installation, having more civilian then military personnel. Even more unique was the work performed by the civilian population, work that required highly educated scientists and engineers. As the breadth, scope, and complexity of the Laboratory’s work increased, more and more technically educated and trained personnel were needed. But, the manpower needs of the nation’s war economy had created a shortage of such people. Tomore » meet its manpower needs, the MED scoured the ranks of the Army for anyone who had technical training and reassigned these men to its laboratories, including Los Alamos, as part of its Special Engineer Detachment (SED). Among the SEDs assigned to Los Alamos was Val Fitch, who was awarded the Nobel Prize in Physics in 1980. Another was Al Van Vessem, who helped stack the TNT for the 100 ton test, bolted together the Trinity device, and rode shotgun with the bomb has it was driven from Los Alamos to ground zero.« less

Environmental analysis of Lower Pueblo/Lower Los Alamos Canyon, Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferenbaugh, R.W.; Buhl, T.E.; Stoker, A.K.

1994-12-01

The radiological survey of the former radioactive waste treatment plant site (TA-45), Acid Canyon, Pueblo Canyon, and Los Alamos Canyon found residual contamination at the site itself and in the channel and banks of Acid, Pueblo, and lower Los Alamos Canyons all the way to the Rio Grande. The largest reservoir of residual radioactivity is in lower Pueblo Canyon, which is on DOE property. However, residual radioactivity does not exceed proposed cleanup criteria in either lower Pueblo or lower Los Alamos Canyons. The three alternatives proposed are (1) to take no action, (2) to construct a sediment trap in lowermore » Pueblo Canyon to prevent further transport of residual radioactivity onto San Ildefonso Indian Pueblo land, and (3) to clean the residual radioactivity from the canyon system. Alternative 2, to cleanup the canyon system, is rejected as a viable alternative. Thousands of truckloads of sediment would have to be removed and disposed of, and this effort is unwarranted by the low levels of contamination present. Residual radioactivity levels, under either present conditions or projected future conditions, will not result in significant radiation doses to persons exposed. Modeling efforts show that future transport activity will not result in any residual radioactivity concentrations higher than those already existing. Thus, although construction of a sediment trap in lower Pueblo Canyon is a viable alternative, this effort also is unwarranted, and the no-action alternative is the preferred alternative.« less

New Generation of Los Alamos Opacity Tables

NASA Astrophysics Data System (ADS)

Colgan, James; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

2016-05-01

We present a new generation of Los Alamos OPLIB opacity tables that have been computed using the ATOMIC code. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the long-standing `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

Criticality calculations of the Very High Temperature reactor Critical Assembly benchmark with Serpent and SCALE/KENO-VI

DOE PAGES

Bostelmann, Friederike; Hammer, Hans R.; Ortensi, Javier; ...

2015-12-30

Within the framework of the IAEA Coordinated Research Project on HTGR Uncertainty Analysis in Modeling, criticality calculations of the Very High Temperature Critical Assembly experiment were performed as the validation reference to the prismatic MHTGR-350 lattice calculations. Criticality measurements performed at several temperature points at this Japanese graphite-moderated facility were recently included in the International Handbook of Evaluated Reactor Physics Benchmark Experiments, and represent one of the few data sets available for the validation of HTGR lattice physics. Here, this work compares VHTRC criticality simulations utilizing the Monte Carlo codes Serpent and SCALE/KENO-VI. Reasonable agreement was found between Serpent andmore » KENO-VI, but only the use of the latest ENDF cross section library release, namely the ENDF/B-VII.1 library, led to an improved match with the measured data. Furthermore, the fourth beta release of SCALE 6.2/KENO-VI showed significant improvements from the current SCALE 6.1.2 version, compared to the experimental values and Serpent.« less

Los Alamos National Laboratory Overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neu, Mary

Mary Neu, Associate Director for Chemistry, Life and Earth Sciences at Los Alamos National Laboratory, delivers opening remarks at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM.

Additive manufacturing capabilities applied to inertial confinement confusion at Los Alamos National Laboratory

DOE PAGES

Cardenas, Tana; Schmidt, Derek William; Peterson, Dominic S.

2016-08-01

We describe the use at Los Alamos National Laboratory of additive manufacturing (AM) for a variety of jigs and coating, assembly, and radiography fixtures. Additive manufacturing has also been used to produce shipping containers of complex design that would be too costly to have fabricated using traditional techniques. The current goal for AM use in target fabrication is to increase target accuracy and rigidity. This has been realized by implementing AM into target stalk fabrication, allowing increased complexity to address target strength and the addition of features for alignment at facilities. As a result, we will describe the fabrication ofmore » these components and our plans to utilize AM in the future.« less

THE HOT CRITICAL ASSEMBLY $sub 4$CESAR$sub 4$ (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanguy, P.

1963-07-01

With Cesar, the Cadarache Center for Nuclear Studies will be equipped with a zero-power critical assembly, which will enable it to obtain the data necessary for the development of natural uranium, graphite, gas reactors. Reactivity balance, evolution of the reactivity, and deformation of the flux curves are to be studied. These studies will complement those already being done on Marius, but carried out at room temperature; in Cesar the graphite temperature can reach 500 deg C. (auth)

Los Alamos County Fire Department LAFD: TA-55 PF-4 Facility Familiarization Tour, OJT 55260

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutherford, Victor Stephen

Los Alamos National Laboratory (LANL) will conduct familiarization tours for Los Alamos County Fire Department (LAFD) personnel at the Plutonium Facility (PF-4) at Technical Area (TA)-55. These familiarization tours are official LANL business; the purpose of these tours is to orient the firefighters to the facility so that they can respond efficiently and quickly to a variety of emergency situations. This orientation includes the ingress and egress of the area and buildings, layout and organization of the facility, evacuation procedures and assembly points, and areas of concern within the various buildings at the facility. LAFD firefighters have the skills andmore » abilities to perform firefighting operations and other emergency response tasks that cannot be provided by other LANL personnel who have the required clearance level. This handout provides details of the information, along with maps and diagrams, to be presented during the familiarization tours. The handout will be distributed to the trainees at the time of the tour. A corresponding checklist will also be used as guidance during the familiarization tours to ensure that all required information is presented to LAFD personnel.« less

Carbon Stripper Foils Used in the Los Alamos PSR

NASA Astrophysics Data System (ADS)

Borden, M.; Plum, M. A.; Sugai, I.

1997-05-01

Carbon stripper foils produced by the modified controlled ACDC arc discharge method (mCADAD) at the Institute for Nuclear Study by Dr. Isao Sugai have been tested and used for high current 800-MeV beam production in the Proton Storage Ring (PSR) since 1993. Two approximately 110 μg/cm2 foils are sandwiched together to produce an equivalent 220 μg/cm^2 foil. The combined foil is supported by 4-5 μm diameter carbon fibers attached to an aluminum frame. These foils have survived as long as five months during PSR normal beam production of near 70 μA on target average current. Typical life-times of other foils vary from seven to fourteen days with lower on-target average current. Beam loss data also indicate that Sugai's foils have slower shrinkage rates than other foils. Equipment has been assembled and used to produce foils by the mCADAD method at Los Alamos. These foils will be tested during 1997 operation.

SEDs at Los Alamos: A Personal Memoir

NASA Astrophysics Data System (ADS)

Bederson, Benjamin

2001-03-01

I have written this personal memoir approximately 55 years after the events I describe. It is based almost exclusively on memory, since apart from the diary I kept while on Tinian, I have few documents concerning it. It covers my service in the U.S. Army's Special Engineering Detachment (SED) in Oak Ridge and Los Alamos in 1944-45, on Tinian island, the launching pad for the bombing raids on Japan, in the summer and fall of 1945, and my return to Los Alamos until my discharge in January 1946.

A Critical Appraisal of RAFT-Mediated Polymerization-Induced Self-Assembly

PubMed Central

2016-01-01

Recently, polymerization-induced self-assembly (PISA) has become widely recognized as a robust and efficient route to produce block copolymer nanoparticles of controlled size, morphology, and surface chemistry. Several reviews of this field have been published since 2012, but a substantial number of new papers have been published in the last three years. In this Perspective, we provide a critical appraisal of the various advantages offered by this approach, while also pointing out some of its current drawbacks. Promising future research directions as well as remaining technical challenges and unresolved problems are briefly highlighted. PMID:27019522

Experimental physics characteristics of a heavy-metal-reflected fast-spectrum critical assembly

NASA Technical Reports Server (NTRS)

Heneveld, W. H.; Paschall, R. K.; Springer, T. H.; Swanson, V. A.; Thiele, A. W.; Tuttle, R. J.

1971-01-01

A zero-power critical assembly was designed, constructed, and operated for the purpose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-7 cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power electric conversion system. The experimental program consisted basically of measuring the differential neutron spectra and the changes in critical mass that accompanied the stepwise addition of (Li-7)3N, Hf, Ta, and W to a basic core fueled with U metal in a pin-type Ta honeycomb structure. In addition, experimental results were obtained on power distributions, control characteristics, neutron lifetime, and reactivity worths of numerous absorber, structural, and scattering materials.

Los Alamos Explosives Performance Key to Stockpile Stewardship

ScienceCinema

Dattelbaum, Dana

2018-02-14

As the U.S. Nuclear Deterrent ages, one essential factor in making sure that the weapons will continue to perform as designed is understanding the fundamental properties of the high explosives that are part of a nuclear weapons system. As nuclear weapons go through life extension programs, some changes may be advantageous, particularly through the addition of what are known as "insensitive" high explosives that are much less likely to accidentally detonate than the already very safe "conventional" high explosives that are used in most weapons. At Los Alamos National Laboratory explosives research includes a wide variety of both large- and small-scale experiments that include small contained detonations, gas and powder gun firings, larger outdoor detonations, large-scale hydrodynamic tests, and at the Nevada Nuclear Security Site, underground sub-critical experiments.

ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

NASA Astrophysics Data System (ADS)

Kahler, A. C.; MacFarlane, R. E.; Mosteller, R. D.; Kiedrowski, B. C.; Frankle, S. C.; Chadwick, M. B.; McKnight, R. D.; Lell, R. M.; Palmiotti, G.; Hiruta, H.; Herman, M.; Arcilla, R.; Mughabghab, S. F.; Sublet, J. C.; Trkov, A.; Trumbull, T. H.; Dunn, M.

2011-12-01

The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., "ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data," Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected

Fifty-one years of Los Alamos Spacecraft

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fenimore, Edward E.

2014-09-04

From 1963 to 2014, the Los Alamos National Laboratory was involved in at least 233 spacecraft. There are probably only one or two institutions in the world that have been involved in so many spacecraft. Los Alamos space exploration started with the Vela satellites for nuclear test detection, but soon expanded to ionospheric research (mostly barium releases), radioisotope thermoelectric generators, solar physics, solar wind, magnetospheres, astrophysics, national security, planetary physics, earth resources, radio propagation in the ionosphere, and cubesats. Here, we present a list of the spacecraft, their purpose, and their launch dates for use during RocketFest

Using the Internet in Middle Schools: A Model for Success. A Collaborative Effort between Los Alamos National Laboratory (LANL) and Los Alamos Middle School (LAMS).

ERIC Educational Resources Information Center

Addessio, Barbara K.; And Others

Los Alamos National Laboratory (LANL) developed a model for school networking using Los Alamos Middle School as a testbed. The project was a collaborative effort between the school and the laboratory. The school secured administrative funding for hardware and software; and LANL provided the network architecture, installation, consulting, and…

A survey of macromycete diversity at Los Alamos National Laboratory, Bandelier National Monument, and Los Alamos County; A preliminary report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarmie, N.; Rogers, F.J.

The authors have completed a 5-year survey (1991--1995) of macromycetes found in Los Alamos County, Los Alamos National Laboratory, and Bandelier National Monument. The authors have compiled a database of 1,048 collections, their characteristics, and identifications. The database represents 123 (98%) genera and 175 (73%) species reliably identified. Issues of habitat loss, species extinction, and ecological relationships are addressed, and comparisons with other surveys are made. With this baseline information and modeling of this baseline data, one can begin to understand more about the fungal flora of the area.

Los Alamos, Toshiba probing Fukushima with cosmic rays

ScienceCinema

Morris, Christopher

2018-01-16

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

New Rad Lab for Los Alamos

ScienceCinema

None

2017-12-09

The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

Notes on Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, Roger Allen

In 1954 an unknown author drafted a report, reprinted below, describing the Laboratory and the community as they existed in late 1953. This report, perhaps intended to be crafted into a public relations document, is valuable because it gives us an autobiographical look at Los Alamos during the first half of the 1950s. It has been edited to enhance readability.

Los Alamos Explosives Performance Key to Stockpile Stewardship

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dattelbaum, Dana

2014-11-03

As the U.S. Nuclear Deterrent ages, one essential factor in making sure that the weapons will continue to perform as designed is understanding the fundamental properties of the high explosives that are part of a nuclear weapons system. As nuclear weapons go through life extension programs, some changes may be advantageous, particularly through the addition of what are known as "insensitive" high explosives that are much less likely to accidentally detonate than the already very safe "conventional" high explosives that are used in most weapons. At Los Alamos National Laboratory explosives research includes a wide variety of both large- andmore » small-scale experiments that include small contained detonations, gas and powder gun firings, larger outdoor detonations, large-scale hydrodynamic tests, and at the Nevada Nuclear Security Site, underground sub-critical experiments.« less

Pre Incident Planning For The Los Alamos National Laboratory

DTIC Science & Technology

2017-12-01

laboratory was asked to design and build the world’s first atomic bomb . The Los Alamos Fire Department (LAFD) provides emergency response services to...Project: the newly established laboratory was asked to design and build the world’s first atomic bomb . The Los Alamos Fire Department (LAFD) provides...lower priority despite its importance to the responders’ scene safety.20 In a Carolina Fire Rescue EMS Journal article, retired New York City

The fast changing landscape of sequencing technologies and their impact on microbial genome assemblies and annotation.

PubMed

Mavromatis, Konstantinos; Land, Miriam L; Brettin, Thomas S; Quest, Daniel J; Copeland, Alex; Clum, Alicia; Goodwin, Lynne; Woyke, Tanja; Lapidus, Alla; Klenk, Hans Peter; Cottingham, Robert W; Kyrpides, Nikos C

2012-01-01

The emergence of next generation sequencing (NGS) has provided the means for rapid and high throughput sequencing and data generation at low cost, while concomitantly creating a new set of challenges. The number of available assembled microbial genomes continues to grow rapidly and their quality reflects the quality of the sequencing technology used, but also of the analysis software employed for assembly and annotation. In this work, we have explored the quality of the microbial draft genomes across various sequencing technologies. We have compared the draft and finished assemblies of 133 microbial genomes sequenced at the Department of Energy-Joint Genome Institute and finished at the Los Alamos National Laboratory using a variety of combinations of sequencing technologies, reflecting the transition of the institute from Sanger-based sequencing platforms to NGS platforms. The quality of the public assemblies and of the associated gene annotations was evaluated using various metrics. Results obtained with the different sequencing technologies, as well as their effects on downstream processes, were analyzed. Our results demonstrate that the Illumina HiSeq 2000 sequencing system, the primary sequencing technology currently used for de novo genome sequencing and assembly at JGI, has various advantages in terms of total sequence throughput and cost, but it also introduces challenges for the downstream analyses. In all cases assembly results although on average are of high quality, need to be viewed critically and consider sources of errors in them prior to analysis. These data follow the evolution of microbial sequencing and downstream processing at the JGI from draft genome sequences with large gaps corresponding to missing genes of significant biological role to assemblies with multiple small gaps (Illumina) and finally to assemblies that generate almost complete genomes (Illumina+PacBio).

Los Alamos Programming Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergen, Benjamin Karl

This is the PDF of a powerpoint presentation from a teleconference on Los Alamos programming models. It starts by listing their assumptions for the programming models and then details a hierarchical programming model at the System Level and Node Level. Then it details how to map this to their internal nomenclature. Finally, a list is given of what they are currently doing in this regard.

Little Boy replication: justification and construction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malenfant, R.E.

A reconstruction of the Little Boy weapon allowed experiments to evaluate yield, leakage measurements for comparison with calculations, and phenomenological measurements to evaluate various in-situ dosimeters. The reconstructed weapon was operated at sustained delayed critical at the Los Alamos Critical Assembly Facility. The present experiments provide a wealth of information to benchmark calculations and demonstrate that the 1965 measurements on the Ichiban assembly (a spherical mockup of Little Boy) were in error.

A progress report on UNICOS misuse detection at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, J.L.; Jackson, K.A.; Stallings, C.A.

An effective method for detecting computer misuse is the automatic monitoring and analysis of on-line user activity. During the past year, Los Alamos enhanced its Network Anomaly Detection and Intrusion Reporter (NADIR) to include analysis of user activity on Los Alamos` UNICOS Crays. In near real-time, NADIR compares user activity to historical profiles and tests activity against expert rules. The expert rules express Los Alamos` security policy and define improper or suspicious behavior. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes the implementation to date of the UNICOS component ofmore » NADIR, along with the operational experiences and future plans for the system.« less

Los Alamos, Toshiba probing Fukushima with cosmic rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, Christopher

2014-06-16

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create imagesmore » of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.« less

Biological assessment for the effluent reduction program, Los Alamos National Laboratory, Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cross, S.P.

1996-08-01

This report describes the biological assessment for the effluent recution program proposed to occur within the boundaries of Los Alamos National Laboratory. Potential effects on wetland plants and on threatened and endangered species are discussed, along with a detailed description of the individual outfalls resulting from the effluent reduction program.

In-situ verification techniques for fast critical assembly cores

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brumbach, S.B.; Amundson, P.I.; Roche, C.T.

1979-01-01

Active and passive autoradiographic techniques were used to obtain piece counts of fuel plates in fast critical assembly drawers and to verify the assembly loading pattern. Active autoradiography using prompt-fission and fission-product radiation was more successful with uranium fuel while passive autoradiography was more successful with plutonium fuel. A source multiplication technique was used to measure changes in reactivity when small quantities (2-2.5 kg) of fissile material were removed from a subcritical reference core of the Zero Power Plutonium Reactor. Efforts to compensate for unsuccessful. Some compensation was achieved by replacing U-238 with polyethylene. The sensitivity for detection of partiallymore » compensated fuel removed from minimum worth regions was approximately 2.5 kg (fissile) for a core containing 2600 kg (fissile). Substitution of polyethylene was detected with a spectral index which was the ratio of the rate of the In-115 (n,..gamma..) reaction to the rate of the In-115 (n,n') reaction. This spectral index was sensitive to the presence of an 0.64-cm-thick, 5.08-cm-high polyethylene column 10-15 cm away from the indium foil. The reactivity worth of Pu-239 was also obtained as a function of location in the reactor core with the use of an inverse kinetics technique. Reactivity worths for Pu-239 varied from a maximum of 58.67 Ih/kg near the core center to a minimum of 14.86 Ih/kg at the core edge.« less

Los Alamos Using Neutrons to Stop Nuclear Smugglers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Favalli, Andrea; Swinhoe, Martyn; Roark, Kevin

Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

Los Alamos Using Neutrons to Stop Nuclear Smugglers

ScienceCinema

Favalli, Andrea; Swinhoe, Martyn; Roark, Kevin

2018-02-14

Los Alamos National Laboratory researchers have successfully demonstrated for the first time that laser-generated neutrons can be enlisted as a useful tool in the War on Terror. The international research team used the short-pulse laser at Los Alamos's TRIDENT facility to generate a neutron beam with novel characteristics that interrogated a closed container to confirm the presence and quantity of nuclear material inside. The successful experiment paves the way for creation of a table-top-sized or truck-mounted neutron generator that could be installed at strategic locations worldwide to thwart smugglers trafficking in nuclear materials.

Little Boy replication: justification and construction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malenfant, R.E.

A reconstruction of the Little Boy weapon allowed experiments to evaluate yield, leakage measurements for comparison with calculations, and phenomenological measurements to evaluate various in-situ dosimeters. The reconstructed weapon was operated at sustained delayed critical at the Los Alamos Critical Assembly Facility. The present experiments provide a wealth of information to benchmark calculations and demonstrate that the 1965 measurements on the Ichiban assembly (a spherical mockup of Little Boy) were in error. 5 references, 2 figures.

Flaws found in Los Alamos safety procedures

NASA Astrophysics Data System (ADS)

Gwynne, Peter

2017-12-01

A US government panel on nuclear safety has discovered a series of safety issues at the Los Alamos National Laboratory, concluding that government oversight of the lab's emergency preparation has been ineffective.

75 FR 72829 - Los Alamos Historical Document Retrieval and Assessment (LAHDRA) Project

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-26

... Historical Document Retrieval and Assessment (LAHDRA) Project The Centers for Disease Control and Prevention... release of the Final Report of the Los Alamos Historical Document Retrieval and Assessment (LAHDRA)Project... information about historical chemical or radionuclide releases from facilities at the Los Alamos National...

A physicists guide to The Los Alamos Primer

NASA Astrophysics Data System (ADS)

Reed, B. Cameron

2016-11-01

In April 1943, a group of scientists at the newly established Los Alamos Laboratory were given a series of lectures by Robert Serber on what was then known of the physics and engineering issues involved in developing fission bombs. Serber’s lectures were recorded in a 24 page report titled The Los Alamos Primer, which was subsequently declassified and published in book form. This paper describes the background to the Primer and analyzes the physics contained in its 22 sections. The motivation for this paper is to provide a firm foundation of the background and contents of the Primer for physicists interested in the Manhattan Project and nuclear weapons.

Environmental surveillance at Los Alamos during 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-07-01

This report describes environmental monitoring activities at Los Alamos National Laboratory for 1994. Data were collected to assess external penetrating radiation, airborne emissions, liquid effluents, radioactivity of environmental materials and food stuffs, and environmental compliance.

Recent Infrasound Calibration Activity at Los Alamos

NASA Astrophysics Data System (ADS)

Whitaker, R. W.; Marcillo, O. E.

2014-12-01

Absolute infrasound sensor calibration is necessary for estimating source sizes from measured waveforms. This can be an important function in treaty monitoring. The Los Alamos infrasound calibration chamber is capable of absolute calibration. Early in 2014 the Los Alamos infrasound calibration chamber resumed operations in its new location after an unplanned move two years earlier. The chamber has two sources of calibration signals. The first is the original mechanical piston, and the second is a CLD Dynamics Model 316 electro-mechanical unit that can be digitally controlled and provide a richer set of calibration options. During 2008-2010 a number of upgrades were incorporated for improved operation and recording. In this poster we give an overview of recent chamber work on sensor calibrations, calibration with the CLD unit, some measurements with different porous hoses and work with impulse sources.

Characterization of the Caliban and Prospero Critical Assemblies Neutron Spectra for Integral Measurements Experiments

NASA Astrophysics Data System (ADS)

Casoli, P.; Authier, N.; Jacquet, X.; Cartier, J.

2014-04-01

Caliban and Prospero are two highly enriched uranium metallic core reactors operated on the CEA Center of Valduc. These critical assemblies are suitable for integral experiments, such as fission yields measurements or perturbation measurements, which have been carried out recently on the Caliban reactor. Different unfolding methods, based on activation foils and fission chambers measurements, are used to characterize the reactor spectra and especially the Caliban spectrum, which is very close to a pure fission spectrum.

Geothermal investigation of spring and well waters of the Los Alamos Region, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goff, F.E.; Sayer, S.

1980-04-01

The chemical and isotopic characters of 20 springs and wells in the Los Alamos area were investigated for indications of geothermal potential. These waters were compared with known hot and mineral springs from adjacent Valles Caldera and San Ysidro. All waters in the Los Alamos area are composed of meteoric water. Isotopic data show that the two primary aquifers beneath the Los Alamos region have different recharge areas. Relatively high concentrations of lithium, arsenic, chlorine, boron, and fluorine in some of the Los Alamos wells suggest these waters may contain a small fraction of thermal/mineral water of deep origin. Thermalmore » water probably rises up high-angle faults associated with a graben of the Rio Grande rift now buried by the Pajarito Plateau.« less

Penetrating radiation: applications at Los Alamos National Laboratory

NASA Astrophysics Data System (ADS)

Watson, Scott; Hunter, James; Morris, Christopher

2013-09-01

Los Alamos has used penetrating radiography extensively throughout its history dating back to the Manhattan Project where imaging dense, imploding objects was the subject of intense interest. This interest continues today as major facilities like DARHT1 have become the mainstay of the US Stockpile Stewardship Program2 and the cornerstone of nuclear weapons certification. Meanwhile, emerging threats to national security from cargo containers and improvised explosive devices (IEDs) have invigorated inspection efforts using muon tomography, and compact x-ray radiography. Additionally, unusual environmental threats, like those from underwater oil spills and nuclear power plant accidents, have caused renewed interest in fielding radiography in severe operating conditions. We review the history of penetrating radiography at Los Alamos and survey technologies as presently applied to these important problems.

Los Alamos National Laboratory Human and Intellectual Capital for Sustaining Nuclear Deterrence

DOE Office of Scientific and Technical Information (OSTI.GOV)

McAlpine, Bradley

2015-04-01

This paper provides an overview of the current human and intellectual capital at Los Alamos National Laboratory, through specific research into the statistics and demographics as well as numerous personal interviews at all levels of personnel. Based on this information, a series of recommendations are provided to assist Los Alamos National Laboratory in ensuring the future of the human and intellectual capital for the nuclear deterrence mission. While the current human and intellectual capital is strong it stands on the precipice and action must be taken to ensure Los Alamos National Laboratory maintains leadership in developing and sustaining national nuclearmore » capabilities. These recommendations may be applicable to other areas of the nuclear enterprise, including the Air Force, after further research and study.« less

Los Alamos Before and After the Fire

NASA Technical Reports Server (NTRS)

2002-01-01

On May 4, 2000, a prescribed fire was set at Bandelier National Monument, New Mexico, to clear brush and dead and dying undergrowth to prevent a larger, subsequent wildfire. Unfortunately, due to high winds and extremely dry conditions in the surrounding area, the prescribed fire quickly raged out of control and, by May 10, the blaze had spread into the nearby town of Los Alamos. In all, more than 20,000 people were evacuated from their homes and more than 200 houses were destroyed as the flames consumed about 48,000 acres in and around the Los Alamos area. The pair of images above were acquired by the Enhanced Thematic Mapper Plus (ETM+) sensor, flying aboard NASA's Landsat 7 satellite, shortly before the Los Alamos fire (top image, acquired April 14) and shortly after the fire was extinguished (lower image, June 17). The images reveal the extent of the damage caused by the fire. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false-color image where vegetation appears as bright to dark green. Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. In the lower image, the areas recently burned appear bright red. Landsat 7 data courtesy United States Geological Survey EROS DataCenter. Images by Robert Simmon, NASA GSFC.

Los Alamos National Laboratory Facility Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Ronald Owen

2015-06-05

This series of slides depicts the Los Alamos Neutron Science Center (LANSCE). The Center's 800-MeV linac produces H + and H - beams as well as beams of moderated (cold to 1 MeV) and unmoderated (0.1 to 600 MeV) neutrons. Experimental facilities and their capabilities and characteristics are outlined. Among these are LENZ, SPIDER, and DANCE.

Los Alamos National Laboratory Prepares for Fire Season

ScienceCinema

L’Esperance, Manny

2018-01-16

Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

Los Alamos National Laboratory Prepares for Fire Season

DOE Office of Scientific and Technical Information (OSTI.GOV)

L’Esperance, Manny

Through the establishment of a Wildland Fire Program Office, and the Interagency Fire Base located on Laboratory property, Los Alamos National Laboratory is continuing and improving a program to prepare for wildland fire.

Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharirli, M.; Rand, J.L.; Sasser, M.K.

1992-01-01

The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief reviewmore » of the studies involved in Phases I and II of the program.« less

Limited-scope probabilistic safety analysis for the Los Alamos Meson Physics Facility (LAMPF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharirli, M.; Rand, J.L.; Sasser, M.K.

1992-12-01

The reliability of instrumentation and safety systems is a major issue in the operation of accelerator facilities. A probabilistic safety analysis was performed or the key safety and instrumentation systems at the Los Alamos Meson Physics Facility (LAMPF). in Phase I of this unique study, the Personnel Safety System (PSS) and the Current Limiters (XLs) were analyzed through the use of the fault tree analyses, failure modes and effects analysis, and criticality analysis. Phase II of the program was done to update and reevaluate the safety systems after the Phase I recommendations were implemented. This paper provides a brief reviewmore » of the studies involved in Phases I and II of the program.« less

Nuclear criticality safety: 5-day training course

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlesser, J.A.

1992-11-01

This compilation of notes is presented as a source reference for the criticality safety course. It represents the contributions of many people, particularly Tom McLaughlin, the course's primary instructor. At the completion of this training course, the attendee will: be able to define terms commonly used in nuclear criticality safety; be able to appreciate the fundamentals of nuclear criticality safety; be able to identify factors which affect nuclear criticality safety; be able to identify examples of criticality controls as used at Los Alamos; be able to identify examples of circumstances present during criticality accidents; be able to identify examples ofmore » computer codes used by the nuclear criticality safety specialist; be able to identify examples of safety consciousness required in nuclear criticality safety.« less

History of Los Alamos Participation in Active Experiments in Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pongratz, Morris B.

Beginning with the Teak nuclear test in 1958, Los Alamos has a long history of participation in active experiments in space. The last pertinent nuclear tests were the five explosions as part of the Dominic series in 1962. The Partial Test Ban Treaty signed in August 1963 prohibited all test detonations of nuclear weapons except for those conducted underground. Beginning with the “Apple” thermite barium release in June 1968 Los Alamos has participated in nearly 100 non-nuclear experiments in space, the last being the NASA-sponsored “AA-2” strontium and europium doped barium thermite releases in the Arecibo beam in July ofmore » 1992. The rationale for these experiments ranged from studying basic plasma processes such as gradientdriven structuring and velocity-space instabilities to illuminating the convection of plasmas in the ionosphere and polar cap to ionospheric depletion experiments to the B.E.A.R. 1-MeV neutral particle beam test in 1989. This report reviews the objectives, techniques and diagnostics of Los Alamos participation in active experiments in space.« less

Water Supply at Los Alamos during 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. N. Maes; S. G. McLin; W. D. Purtymun

1998-12-01

Production of potable municipal water supplies during 1997 totaled about 1,285.9 million gallons from wells in the Guaje, Pajarito, and Otowi well fields. There was no water used from the spring gallery in Water Canyon or from Guaje Reservoir during 1997. About 2.4 million gallons of water from Los Alamos Reservoir was used to irrigate public parks and recreational lands. The total water usage in 1997 was about 1,288.3 million gallons, or about 135 gallons per day per person living in Los Alamos County. Groundwater pumpage was down about 82.2 million gallons in 1997 compared with the pumpage in 1996.more » Four new replacement wells were drilled and cased in Guaje Canyon between October 1997 and March 1998. These wells are currently being developed and aquifer tests are being performed. A special report summarizing the geological, geophysical, and well construction logs will be issued in the near future for these new wells.« less

Los Alamos high-power proton linac designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, G.P.

1995-10-01

Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

Audit Report, "Fire Protection Deficiencies at Los Alamos National Laboratory"

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2009-06-01

The Department of Energy's Los Alamos National Laboratory (Los Alamos) maintains some of the Nation's most important national security assets, including nuclear materials. Many of Los Alamos' facilities are located in close proximity to one another, are occupied by large numbers of contract and Federal employees, and support activities ranging from nuclear weapons design to science-related activities. Safeguarding against fires, regardless of origin, is essential to protecting employees, surrounding communities, and national security assets. On June 1, 2006, Los Alamos National Security, LLC (LANS), became the managing and operating contractor for Los Alamos, under contract with the Department's National Nuclearmore » Security Administration (NNSA). In preparation for assuming its management responsibilities at Los Alamos, LANS conducted walk-downs of the Laboratory's facilities to identify pre-existing deficiencies that could give rise to liability, obligation, loss or damage. The walk-downs, which identified 812 pre-existing fire protection deficiencies, were conducted by subject matter professionals, including fire protection experts. While the Los Alamos Site Office has overall responsibility for the effectiveness of the fire protection program, LANS, as the Laboratory's operating contractor, has a major, day-to-day role in minimizing fire-related risks. The issue of fire protection at Los Alamos is more than theoretical. In May 2000, the 'Cerro Grande' fire burned about 43,000 acres, including 7,700 acres of Laboratory property. Due to the risk posed by fire to the Laboratory's facilities, workforce, and surrounding communities, we initiated this audit to determine whether pre-existing fire protection deficiencies had been addressed. Our review disclosed that LANS had not resolved many of the fire protection deficiencies that had been identified in early 2006: (1) Of the 296 pre-existing deficiencies we selected for audit, 174 (59 percent) had not been

Wireline-rotary air coring of the Bandelier Tuff, Los Alamos, New Mexico

USGS Publications Warehouse

Teasdale, W.E.; Pemberton, R.R.

1984-01-01

This paper describes experiments using wireline-rotary air-coring techniques conducted in the Bandelier Tuff using a modified standard wireline core-barrel system. The modified equipment was used to collect uncontaminated cores of unconsolidated ash and indurated tuff at Los Alamos, New Mexico. Core recovery obtained from the 210-foot deep test hole was about 92 percent. A standard HQ-size, triple-tube wireline core barrel (designed for the passage of liquid drilling fluids) was modified for air coring as follows: (1) Air passages were milled in the latch body part of the head assembly; (2) the inside dimension of the outer core barrel tube was machined and honed to provide greater clearance between the inner and outer barrels; (3) oversized reaming devices were added to the outer core barrel and the coring bit to allow more clearance for air and cuttings return; (4) the eight discharge ports in the coring bit were enlarged. To control airborne-dust pollution, a dust-and-cuttings discharge subassembly, designed and built by project personnel, was used. (USGS)

Los Alamos on Radio Café: Nina Lanza

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanza, Nina; Domandi, Mary-Charlotte

2017-04-11

First up in the new series is Los Alamos National Laboratory’s Nina Lanza from the Space and Remote Sensing group. Lanza is a planetary geologist who has been part of the Mars Curiosity Rover “ChemCam” team since 2012.

Airport-Noise Levels and Annoyance Model (ALAMO) user's guide

NASA Technical Reports Server (NTRS)

Deloach, R.; Donaldson, J. L.; Johnson, M. J.

1986-01-01

A guide for the use of the Airport-Noise Level and Annoyance MOdel (ALAMO) at the Langley Research Center computer complex is provided. This document is divided into 5 primary sections, the introduction, the purpose of the model, and an in-depth description of the following subsystems: baseline, noise reduction simulation and track analysis. For each subsystem, the user is provided with a description of architecture, an explanation of subsystem use, sample results, and a case runner's check list. It is assumed that the user is familiar with the operations at the Langley Research Center (LaRC) computer complex, the Network Operating System (NOS 1.4) and CYBER Control Language. Incorporated within the ALAMO model is a census database system called SITE II.

Transmutation of uranium and thorium in the particle field of the Quinta sub-critical assembly

NASA Astrophysics Data System (ADS)

Hashemi-Nezhad, S. R.; Asquith, N. L.; Voronko, V. A.; Sotnikov, V. V.; Zhadan, Alina; Zhuk, I. V.; Potapenko, A.; Husak, Krystsina; Chilap, V.; Adam, J.; Baldin, A.; Berlev, A.; Furman, W.; Kadykov, M.; Khushvaktov, J.; Kudashkin, I.; Mar'in, I.; Paraipan, M.; Pronskih, V.; Solnyshkin, A.; Tyutyunnikov, S.

2018-03-01

The fission rates of natural uranium and thorium were measured in the particle field of Quinta, a 512 kg natural uranium target-blanket sub-critical assembly. The Quinta assembly was irradiated with deuterons of energy 4 GeV from the Nuclotron accelerator of the Joint Institute for Nuclear Research (JINR), Dubna, Russia. Fission rates of uranium and thorium were measured using Gamma spectroscopy and fission track techniques. The production rate of 239Np was also measured. The obtained experimental results were compared with Monte Carlo predictions using the MCNPX 2.7 code employing the physics and fission-evaporation models of INCL4-ABLA, CEM03.03 and LAQGSM03.03. Some of the neutronic characteristics of the Quinta are compared with the "Energy plus Transmutation (EpT)" subcritical assembly, which is composed of a lead target and natU blanket. This comparison clearly demonstrates the importance of target material, neutron moderator and reflector types on the performance of a spallation neutron driven subcritical system. As the dimensions of the Quinta are very close to those of an optimal multi-rod-uranium target, the experimental and Monte Carlo calculation results presented in this paper provide insights on the particle field within a uranium target as well as in Accelerator Driven Systems in general.

A New Generation of Los Alamos Opacity Tables

DOE PAGES

Colgan, James Patrick; Kilcrease, David Parker; Magee, Jr., Norman H.; ...

2016-01-26

We present a new, publicly available, set of Los Alamos OPLIB opacity tables for the elements hydrogen through zinc. Our tables are computed using the Los Alamos ATOMIC opacity and plasma modeling code, and make use of atomic structure calculations that use fine-structure detail for all the elements considered. Our equation-of-state (EOS) model, known as ChemEOS, is based on the minimization of free energy in a chemical picture and appears to be a reasonable and robust approach to determining atomic state populations over a wide range of temperatures and densities. In this paper we discuss in detail the calculations thatmore » we have performed for the 30 elements considered, and present some comparisons of our monochromatic opacities with measurements and other opacity codes. We also use our new opacity tables in solar modeling calculations and compare and contrast such modeling with previous work.« less

Neutron spectra as a function of angle at two meters from the Little Boy assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffith, R.V.; Huntzinger, C.J.; Thorngate, J.H.

1984-07-02

Measurements of neutron spectra produced by the Los Alamos National Laboratory (LANL) Little Boy replica assembly (Comet) were made with a combined multisphere and liquid scintillator system, that has been widely used at the Lawrence Livermore National Laboratory. The combined system was used for measurements at the side (90/sup 0/) and nose (0/sup 0/) of the assembly; additional measurements were made at 45/sup 0/ using only the liquid scintillator. Data were obtained at two meters from the center of the reactive region of the assembly, with good agreement between the multisphere and scintillator results. Comparison with liquid scintillator measurements performedmore » by experimenters from the Canadian Defence Research Establishment, Ottawa (DREO) and calculations from LANL depended on the specific angle, obtaining the best agreement at 90/sup 0/. 32 references, 11 figures, 4 tables.« less

Multi-scale coarse-graining for the study of assembly pathways in DNA-brick self-assembly.

PubMed

Fonseca, Pedro; Romano, Flavio; Schreck, John S; Ouldridge, Thomas E; Doye, Jonathan P K; Louis, Ard A

2018-04-07

Inspired by recent successes using single-stranded DNA tiles to produce complex structures, we develop a two-step coarse-graining approach that uses detailed thermodynamic calculations with oxDNA, a nucleotide-based model of DNA, to parametrize a coarser kinetic model that can reach the time and length scales needed to study the assembly mechanisms of these structures. We test the model by performing a detailed study of the assembly pathways for a two-dimensional target structure made up of 334 unique strands each of which are 42 nucleotides long. Without adjustable parameters, the model reproduces a critical temperature for the formation of the assembly that is close to the temperature at which assembly first occurs in experiments. Furthermore, the model allows us to investigate in detail the nucleation barriers and the distribution of critical nucleus shapes for the assembly of a single target structure. The assembly intermediates are compact and highly connected (although not maximally so), and classical nucleation theory provides a good fit to the height and shape of the nucleation barrier at temperatures close to where assembly first occurs.

Multi-scale coarse-graining for the study of assembly pathways in DNA-brick self-assembly

NASA Astrophysics Data System (ADS)

Fonseca, Pedro; Romano, Flavio; Schreck, John S.; Ouldridge, Thomas E.; Doye, Jonathan P. K.; Louis, Ard A.

2018-04-01

Inspired by recent successes using single-stranded DNA tiles to produce complex structures, we develop a two-step coarse-graining approach that uses detailed thermodynamic calculations with oxDNA, a nucleotide-based model of DNA, to parametrize a coarser kinetic model that can reach the time and length scales needed to study the assembly mechanisms of these structures. We test the model by performing a detailed study of the assembly pathways for a two-dimensional target structure made up of 334 unique strands each of which are 42 nucleotides long. Without adjustable parameters, the model reproduces a critical temperature for the formation of the assembly that is close to the temperature at which assembly first occurs in experiments. Furthermore, the model allows us to investigate in detail the nucleation barriers and the distribution of critical nucleus shapes for the assembly of a single target structure. The assembly intermediates are compact and highly connected (although not maximally so), and classical nucleation theory provides a good fit to the height and shape of the nucleation barrier at temperatures close to where assembly first occurs.

James L. Tuck Los Alamos ball lightning pioneer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, D.A.

1999-07-01

James Tuck was well known for starting the Project Sherwood group at Los Alamos Scientific Laboratory in 1952. This group was formed to study and develop concepts for controlled fusion energy. In his later years after retiring from Controlled Fusion Division, he continued research at Los Alamos on the topic of ball lightning. He traveled widely giving lectures on both observations of others and his own experimental efforts. He collected anecdotal observations obtained from those in his lecture audiences during his travels and from responses from newspaper articles where he asked for specific information from ball lightning observers. He finallymore » cut off this collection of data when the number of responses became overwhelming. The author's primary publication on ball lightning was a short laboratory report. He planned on publishing a book on the subject but this was never completed before his death. Tuck focused his experimental effort on attempting to duplicate the production of plasma balls claimed to be observed in US Navy submarines when a switch was opened under overload conditions with battery power. During lunch breaks he made use of a Los Alamos N-division battery bank facility to mock up a submarine power pack and switch gear. This non-funded effort was abruptly terminated when an explosion occurred in the facility. An overview of Tuck's research and views will be given. The flavor Jim's personality as well as a ball produced with his experimental apparatus will be shown using video chips.« less

A Temporospatial Map That Defines Specific Steps at Which Critical Surfaces in the Gag MA and CA Domains Act during Immature HIV-1 Capsid Assembly in Cells

PubMed Central

Robinson, Bridget A.; Reed, Jonathan C.; Geary, Clair D.; Swain, J. Victor

2014-01-01

ABSTRACT During HIV-1 assembly, Gag polypeptides target to the plasma membrane, where they multimerize to form immature capsids that undergo budding and maturation. Previous mutational analyses identified residues within the Gag matrix (MA) and capsid (CA) domains that are required for immature capsid assembly, and structural studies showed that these residues are clustered on four exposed surfaces in Gag. Exactly when and where the three critical surfaces in CA function during assembly are not known. Here, we analyzed how mutations in these four critical surfaces affect the formation and stability of assembly intermediates in cells expressing the HIV-1 provirus. The resulting temporospatial map reveals that critical MA residues act during membrane targeting, residues in the C-terminal CA subdomain (CA-CTD) dimer interface are needed for the stability of the first membrane-bound assembly intermediate, CA-CTD base residues are necessary for progression past the first membrane-bound intermediate, and residues in the N-terminal CA subdomain (CA-NTD) stabilize the last membrane-bound intermediate. Importantly, we found that all four critical surfaces act while Gag is associated with the cellular facilitators of assembly ABCE1 and DDX6. When correlated with existing structural data, our findings suggest the following model: Gag dimerizes via the CA-CTD dimer interface just before or during membrane targeting, individual CA-CTD hexamers form soon after membrane targeting, and the CA-NTD hexameric lattice forms just prior to capsid release. This model adds an important new dimension to current structural models by proposing the potential order in which key contacts within the immature capsid lattice are made during assembly in cells. IMPORTANCE While much is known about the structure of the completed HIV-1 immature capsid and domains of its component Gag proteins, less is known about the sequence of events leading to formation of the HIV-1 immature capsid. Here we used

Upgrades and Enclosure of Building 15 at Technical Area 40: Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plimpton, Kathryn D; Garcia, Kari L. M; Brunette, Jeremy Christopher

The U.S. Department of Energy, National Nuclear Security Administration, Los Alamos Field Office (Field Office) proposes to upgrade and enclose Building 15 at Technical Area (TA) 40, Los Alamos National Laboratory. Building TA-40-15, a Cold War-era firing site, was determined eligible for listing in the National Register of Historic Places (Register) in DX Division’s Facility Strategic Plan: Consolidation and Revitalization at Technical Areas 6, 8, 9, 14, 15, 22, 36, 39, 40, 60, and 69 (McGehee et al. 2005). Building TA-40-15 was constructed in 1950 to support detonator testing. The firing site will be enclosed by a steel building tomore » create a new indoor facility that will allow for year-round mission capability. Enclosing TA-40-15 will adversely affect the building by altering the characteristics that make it eligible for the Register. In compliance with Section 106 of the National Historic Preservation Act of 1966, as amended, the Field Office is initiating consultation for this proposed undertaking. The Field Office is also requesting concurrence with the use of standard practices to resolve adverse effects as defined in the Programmatic Agreement among the U.S. Department of Energy, National Nuclear Security Administration, Los Alamos Field Office, the New Mexico State Historic Preservation Office and the Advisory Council on Historic Preservation Concerning Management of the Historic Properties at Los Alamos National Laboratory, Los Alamos, New Mexico.« less

Los Alamos on Radio Café: Ludmil Alexandrov

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domandi, Mary-Charlotte; Alexandrov, Ludmil

In a creative breakthrough in cancer research, Ludmil Alexandrov, the J. Robert Oppenheimer Distinguished Postdoctoral Fellow at Los Alamos National Laboratory, combines Big Data, supercomputing and machine-learning to identify the telltale mutations of cancer. Knowing these mutational signatures can help researchers develop new methods of prevention.

Neutron spectrum measurements using proton recoil proportional counters: results of measurements of leakage spectra for the Little Boy assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bennett, E.F.; Yule, T.J.

1984-01-01

Measurements of degraded fission-neutron spectra using recoil proportional counters are done routinely for studies involving fast reactor mockups. The same techniques are applicable to measurements of neutron spectra required for personnel dosimetry in fast neutron environments. A brief discussion of current applications of these methods together with the results of a measurement made on the LITTLE BOY assembly at Los Alamos are here described.

Induction Inserts at the Los Alamos PSR

NASA Astrophysics Data System (ADS)

Ng, K. Y.

2002-12-01

Ferrite-loaded induction tuners installed in the Los Alamos Proton Storage Ring have been successful in compensating space-charge effects. However, the resistive part of the ferrite introduces unacceptable microwave instability and severe bunch lengthening. An effective cure was found by heating the ferrite cores up to ˜ 130°C. An understanding of the instability and cure is presented.

Los Alamos Team Demonstrates Bottle Scanner Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espy, Michelle; Schultz, Larry

2014-05-06

Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

Los Alamos Team Demonstrates Bottle Scanner Technology

ScienceCinema

Espy, Michelle; Schultz, Larry

2018-02-13

Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

30 CFR 7.45 - Critical characteristics

Code of Federal Regulations, 2011 CFR

2011-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.45 Critical characteristics The following critical characteristics shall be inspected or tested on each battery assembly to...

30 CFR 7.45 - Critical characteristics

Code of Federal Regulations, 2012 CFR

2012-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.45 Critical characteristics The following critical characteristics shall be inspected or tested on each battery assembly to...

30 CFR 7.305 - Critical characteristics.

Code of Federal Regulations, 2010 CFR

2010-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.305 Critical characteristics. The following critical characteristics shall be inspected on each motor assembly to which an...

Analysis of a water moderated critical assembly with anisn-Vitamin C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, L.

1979-03-01

A tightly packed water moderated /sup 233/UO/sub 2/--ThO/sub 2/ critical assembly was analyzed with the Vitamin C library and the 1-D S/s n/ code, ANISN (S/sub 8/,P/sub 3/). The purpose of the study was to provide validation of this calculational model as applied to water-cooled hybrid fusion blankets. The quantities compared were the core eigenvalue and various activation shapes. The calculated eigenvalue was 1.02 +- 0.01. The /sup 233/U fission and /sup 232/Th capture shapes were found to be in good agreement (+-5%) with experiment, except near water--metal boundaries where differences up to 24% were observed. No such error peakingmore » was observed in the /sup 232/Th fast fission shape. We conclude that the model provides good volume averaged reaction rates in water-cooled systems. However, care must be exercised near water boundaries where thermally dependent reaction rates are significantly underestimated.« less

75 FR 1793 - Study Team for the Los Alamos Historical Document Retrieval and Assessment (LAHDRA) Project

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-13

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Study Team for the Los Alamos Historical Document Retrieval and Assessment (LAHDRA) Project The Centers for Disease... the following meeting. Name: Public Meeting of the Study Team for the Los Alamos Historical Document...

Total electron content (TEC) variability at Los Alamos, New Mexico: A comparative study: FORTE-derived TEC analysis

NASA Astrophysics Data System (ADS)

Huang, Zhen; Roussel-Dupré, Robert

2005-12-01

Data collected from Fast On-Orbit Recording of Transient Events (FORTE) satellite-received Los Alamos Portable Pulser (LAPP) signals during 1997-2002 are used to derive the total electron content (TEC) at Los Alamos, New Mexico. The LAPP-derived TECs at Los Alamos are analyzed for diurnal, seasonal, interannual, and 27-day solar cycle variations. Several aspects in deriving TEC are analyzed, including slant to vertical TEC conversion, quartic effects on transionosperic signals, and geomagnetic storm effects on the TEC variance superimposed on the averaged TEC values.

Los Alamos Novel Rocket Design Flight Tested

ScienceCinema

Tappan, Bryce

2018-04-16

Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

Los Alamos Novel Rocket Design Flight Tested

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tappan, Bryce

Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

Experimental physics characteristics of a heavy-metal-reflected fast-spectrum critical assembly

NASA Technical Reports Server (NTRS)

Heneveld, W. H.; Paschall, R. K.; Springer, T. H.; Swanson, V. A.; Thiele, A. W.; Tuttle, R. J.

1972-01-01

A zero-power critical assembly was designed, constructed, and operated for the purpose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power electric conversion system. The range of the previous experimental investigations has been expanded to include the reactivity effects of:(1) surrounding the reactor with 15.24 cm (6 in.) of polyethylene, (2) reducing the heights of a portion of the upper and lower axial reflectors by factors of 2 and 4, (3) adding 45 kg of W to the core uniformly in two steps, (4) adding 9.54 kg of Ta to the core uniformly, and (5) inserting 2.3 kg of polyethylene into the core proper and determining the effect of a Ta addition on the polyethylene worth.

Evaluation of nine popular de novo assemblers in microbial genome assembly.

PubMed

Forouzan, Esmaeil; Maleki, Masoumeh Sadat Mousavi; Karkhane, Ali Asghar; Yakhchali, Bagher

2017-12-01

Next generation sequencing (NGS) technologies are revolutionizing biology, with Illumina being the most popular NGS platform. Short read assembly is a critical part of most genome studies using NGS. Hence, in this study, the performance of nine well-known assemblers was evaluated in the assembly of seven different microbial genomes. Effect of different read coverage and k-mer parameters on the quality of the assembly were also evaluated on both simulated and actual read datasets. Our results show that the performance of assemblers on real and simulated datasets could be significantly different, mainly because of coverage bias. According to outputs on actual read datasets, for all studied read coverages (of 7×, 25× and 100×), SPAdes and IDBA-UD clearly outperformed other assemblers based on NGA50 and accuracy metrics. Velvet is the most conservative assembler with the lowest NGA50 and error rate. Copyright © 2017. Published by Elsevier B.V.

Los Alamos Science: The Human Genome Project. Number 20, 1992

DOE R&D Accomplishments Database

Cooper, N. G.; Shea, N. eds.

1992-01-01

This document provides a broad overview of the Human Genome Project, with particular emphasis on work being done at Los Alamos. It tries to emphasize the scientific aspects of the project, compared to the more speculative information presented in the popular press. There is a brief introduction to modern genetics, including a review of classic work. There is a broad overview of the Genome Project, describing what the project is, what are some of its major five-year goals, what are major technological challenges ahead of the project, and what can the field of biology, as well as society expect to see as benefits from this project. Specific results on the efforts directed at mapping chromosomes 16 and 5 are discussed. A brief introduction to DNA libraries is presented, bearing in mind that Los Alamos has housed such libraries for many years prior to the Genome Project. Information on efforts to do applied computational work related to the project are discussed, as well as experimental efforts to do rapid DNA sequencing by means of single-molecule detection using applied spectroscopic methods. The article introduces the Los Alamos staff which are working on the Genome Project, and concludes with brief discussions on ethical, legal, and social implications of this work; a brief glimpse of genetics as it may be practiced in the next century; and a glossary of relevant terms.

Nuclear Criticality Experimental Research Center (NCERC) Overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goda, Joetta Marie; Grove, Travis Justin; Hayes, David Kirk

The mission of the National Criticality Experiments Research Center (NCERC) at the Device Assembly Facility (DAF) is to conduct experiments and training with critical assemblies and fissionable material at or near criticality in order to explore reactivity phenomena, and to operate the assemblies in the regions from subcritical through delayed critical. One critical assembly, Godiva-IV, is designed to operate above prompt critical. The Nuclear Criticality Experimental Research Center (NCERC) is our nation’s only general-purpose critical experiments facility and is only one of a few that remain operational throughout the world. This presentation discusses the history of NCERC, the general activitiesmore » that makeup work at NCERC, and the various government programs and missions that NCERC supports. Recent activities at NCERC will be reviewed, with a focus on demonstrating how NCERC meets national security mission goals using engineering fundamentals. In particular, there will be a focus on engineering theory and design and applications of engineering fundamentals at NCERC. NCERC activities that relate to engineering education will also be examined.« less

Optical velocimetry at the Los Alamos Proton Radiography Facility

NASA Astrophysics Data System (ADS)

Tupa, Dale; Tainter, Amy; Neukirch, Levi; Hollander, Brian; Buttler, William; Holtkamp, David; The Los Alamos Proton Radiography Team Team

2016-05-01

The Los Alamos Proton Radiography Facility (pRad) employs a high-energy proton beam to image the properties and behavior of materials driven by high explosives. We will discuss features of pRad and describe some recent experiments, highlighting optical diagnostics for surface velocity measurements.

Aqueous Nitrate Recovery Line at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finstad, Casey Charles

2016-06-15

This powerpoint is part of the ADPSM Plutonium Engineering Lecture Series, which is an opportunity for new hires at LANL to get an overview of work done at TA55. It goes into detail about the aqueous nitrate recovery line at Los Alamos National Laboratory.

Equilibrium polymerization models of re-entrant self-assembly

NASA Astrophysics Data System (ADS)

Dudowicz, Jacek; Douglas, Jack F.; Freed, Karl F.

2009-04-01

As is well known, liquid-liquid phase separation can occur either upon heating or cooling, corresponding to lower and upper critical solution phase boundaries, respectively. Likewise, self-assembly transitions from a monomeric state to an organized polymeric state can proceed either upon increasing or decreasing temperature, and the concentration dependent ordering temperature is correspondingly called the "floor" or "ceiling" temperature. Motivated by the fact that some phase separating systems exhibit closed loop phase boundaries with two critical points, the present paper analyzes self-assembly analogs of re-entrant phase separation, i.e., re-entrant self-assembly. In particular, re-entrant self-assembly transitions are demonstrated to arise in thermally activated equilibrium self-assembling systems, when thermal activation is more favorable than chain propagation, and in equilibrium self-assembly near an adsorbing boundary where strong competition exists between adsorption and self-assembly. Apparently, the competition between interactions or equilibria generally underlies re-entrant behavior in both liquid-liquid phase separation and self-assembly transitions.

Evaluation of Macroinvertebrate Communities and Habitat for Selected Stream Reaches at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

L.J. Henne; K.J. Buckley

2005-08-12

This is the second aquatic biological monitoring report generated by Los Alamos National Laboratory's (LANL's) Water Quality and Hydrology Group. The study has been conducted to generate impact-based assessments of habitat and water quality for LANL waterways. The monitoring program was designed to allow for the detection of spatial and temporal trends in water and habitat quality through ongoing, biannual monitoring of habitat characteristics and benthic aquatic macroinvertebrate communities at six key sites in Los Alamos, Sandia, Water, Pajarito, and Starmer's Gulch Canyons. Data were collected on aquatic habitat characteristics, channel substrate, and macroinvertebrate communities during 2001 and 2002. Aquaticmore » habitat scores were stable between 2001 and 2002 at all locations except Starmer's Gulch and Pajarito Canyon, which had lower scores in 2002 due to low flow conditions. Channel substrate changes were most evident at the upper Los Alamos and Pajarito study reaches. The macroinvertebrate Stream Condition Index (SCI) indicated moderate to severe impairment at upper Los Alamos Canyon, slight to moderate impairment at upper Sandia Canyon, and little or no impairment at lower Sandia Canyon, Starmer's Gulch, and Pajarito Canyon. Habitat, substrate, and macroinvertebrate data from the site in upper Los Alamos Canyon indicated severe impacts from the Cerro Grande Fire of 2000. Impairment in the macroinvertebrate community at upper Sandia Canyon was probably due to effluent-dominated flow at that site. The minimal impairment SCI scores for the lower Sandia site indicated that water quality improved with distance downstream from the outfall at upper Sandia Canyon.« less

Los Alamos - A Short History

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, Roger A.

At 5:45 am on the morning of July 16, 1945, the world’s first atomic bomb exploded over a remote section of the southern New Mexican desert known as the Jornada del Muerto, the Journey of Death. Three weeks later, the atomic bombs known as Little Boy and Fat Man brought World War II to an end. Working literally around the clock, these first atomic bombs were designed and built in just thirty months by scientists working at a secret scientific laboratory in the mountains of New Mexico known by its codename, Project Y, better known to the world as Losmore » Alamos.« less

Assembly, alignment and test of the Transiting Exoplanet Survey Satellite (TESS) optical assemblies

NASA Astrophysics Data System (ADS)

Balonek, Gregory; Brown, Joshua J.; Andre, James E.; Chesbrough, Christian D.; Chrisp, Michael P.; Dalpiaz, Michael; Lennon, Joseph; Richards, B. C.; Clark, Kristin E.

2017-08-01

The Transiting Exoplanet Survey Satellite (TESS) will carry four visible waveband, seven-element, refractive F/1.4 lenses, each with a 34 degree diagonal field of view. This paper describes the methods used for the assembly, alignment and test of the four flight optical assemblies. Prior to commencing the build of the four flight optical assemblies, a Risk Reduction Unit (RRU) was successfully assembled and tested [1]. The lessons learned from the RRU were applied to the build of the flight assemblies. The main modifications to the flight assemblies include the inking of the third lens element stray light mitigation, tighter alignment tolerances, and diamond turning for critical mechanical surfaces. Each of the optical assemblies was tested interferometrically and measured with a low coherence distance measuring interferometer (DMI) to predict the optimal shim thickness between the lens assembly and detector before -75°C environmental testing. In addition to individual test data, environmental test results from prior assemblies allow for the exploration of marginal performance differences between each of the optical assemblies.

Los Alamos Science: The Human Genome Project. Number 20, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, N G; Shea, N

1992-01-01

This article provides a broad overview of the Human Genome Project, with particular emphasis on work being done at Los Alamos. It tries to emphasize the scientific aspects of the project, compared to the more speculative information presented in the popular press. There is a brief introduction to modern genetics, including a review of classic work. There is a broad overview of the Genome Project, describing what the project is, what are some of its major five-year goals, what are major technological challenges ahead of the project, and what can the field of biology, as well as society expect tomore » see as benefits from this project. Specific results on the efforts directed at mapping chromosomes 16 and 5 are discussed. A brief introduction to DNA libraries is presented, bearing in mind that Los Alamos has housed such libraries for many years prior to the Genome Project. Information on efforts to do applied computational work related to the project are discussed, as well as experimental efforts to do rapid DNA sequencing by means of single-molecule detection using applied spectroscopic methods. The article introduces the Los Alamos staff which are working on the Genome Project, and concludes with brief discussions on ethical, legal, and social implications of this work; a brief glimpse of genetics as it may be practiced in the next century; and a glossary of relevant terms.« less

An independent evaluation of plutonium body burdens in populations near Los Alamos Laboratory using human autopsy data.

PubMed

Gaffney, Shannon H; Donovan, Ellen P; Shonka, Joseph J; Le, Matthew H; Widner, Thomas E

2013-06-01

In the mid-1940s, the United States began producing atomic weapon components at the Los Alamos National Laboratory (LANL). In an attempt to better understand historical exposure to nearby residents, this study evaluates plutonium activity in human tissue relative to residential location and length of time at residence. Data on plutonium activity in the lung, vertebrae, and liver of nearby residents were obtained during autopsies as a part of the Los Alamos Tissue Program. Participant residential histories and the distance from each residence to the primary plutonium processing buildings at LANL were evaluated in the analysis. Summary statistics, including Student t-tests and simple regressions, were calculated. Because the biological half-life of plutonium can vary significantly by organ, data were analyzed separately by tissue type (lung, liver, vertebrae). The ratios of plutonium activity (vertebrae:liver; liver:lung) were also analyzed in order to evaluate the importance of timing of exposure. Tissue data were available for 236 participants who lived in a total of 809 locations, of which 677 were verified postal addresses. Residents of Los Alamos were found to have higher plutonium activities in the lung than non-residents. Further, those who moved to Los Alamos before 1955 had higher lung activities than those who moved there later. These trends were not observed with the liver, vertebrae, or vertebrae:liver and liver:lung ratio data, however, and should be interpreted with caution. Although there are many limitations to this study, including the amount of available data and the analytical methods used to analyze the tissue, the overall results indicate that residence (defined as the year that the individual moved to Los Alamos) may have had a strong correlation to plutonium activity in human tissue. This study is the first to present the results of Los Alamos Autopsy Program in relation to residential status and location in Los Alamos. Copyright © 2012

Critical Role of the HTLV-1 Capsid N-Terminal Domain for Gag-Gag Interactions and Virus Particle Assembly.

PubMed

Martin, Jessica L; Mendonça, Luiza; Marusinec, Rachel; Zuczek, Jennifer; Angert, Isaac; Blower, Ruth J; Mueller, Joachim D; Perilla, Juan R; Zhang, Wei; Mansky, Louis M

2018-04-25

The retroviral Gag protein is the main structural protein responsible for virus particle assembly and release. Like human immunodeficiency virus type 1 (HIV-1) Gag, human T-cell leukemia virus type 1 (HTLV-1) has a structurally conserved capsid (CA) domain, including a β-hairpin turn and a centralized coiled-coil-like structure of six α helices in the CA amino-terminal domain (NTD) as well as four α-helices in the CA carboxy-terminal domain (CTD). CA drives Gag oligomerization, which is critical for both immature Gag lattice formation and particle production. The HIV-1 CA CTD has previously been shown to be a primary determinant for CA-CA interactions, and while both the HTLV-1 CA NTD and CTD have been implicated in Gag-Gag interactions, our recent observations have implicated the HTLV-1 CA NTD as encoding key determinants that dictate particle morphology. Here, we have conducted alanine-scanning mutagenesis in the HTLV-1 CA NTD nucleotide-encoding sequences spanning the loop regions and amino acids at the beginning and ends of α-helices due to their structural dissimilarity from the HIV-1 CA NTD structure. We analyzed both Gag subcellular distribution and efficiency of particle production for these mutants. We discovered several important residues (i.e., M17, Q47/F48, and Y61). Modeling implicated that these residues reside at the dimer interface (i.e., M17 and Y61) or at the trimer interface (i.e., Q47/F48). Taken together, these observations highlight the critical role of the HTLV-1 CA NTD in Gag-Gag interactions and particle assembly, which is, to the best of our knowledge, in contrast to HIV-1 and other retroviruses. Importance Retrovirus particle assembly and release from infected cells is driven by the Gag structural protein. Gag-Gag interactions, which form an oligomeric lattice structure at a particle budding site, are essential to the biogenesis of an infectious virus particle. The capsid (CA) domain of Gag is generally thought to possess the key

30 CFR 7.45 - Critical characteristics

Code of Federal Regulations, 2014 CFR

2014-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.45 Critical characteristics The following critical characteristics shall be inspected or tested on each battery assembly to... terminations. (e) Strain relief devices for cables leaving boxes. (f) Type, location, and physical protection...

30 CFR 7.45 - Critical characteristics

Code of Federal Regulations, 2013 CFR

2013-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.45 Critical characteristics The following critical characteristics shall be inspected or tested on each battery assembly to... terminations. (e) Strain relief devices for cables leaving boxes. (f) Type, location, and physical protection...

30 CFR 7.45 - Critical characteristics

Code of Federal Regulations, 2010 CFR

2010-07-01

... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.45 Critical characteristics The following critical characteristics shall be inspected or tested on each battery assembly to... terminations. (e) Strain relief devices for cables leaving boxes. (f) Type, location, and physical protection...

In-field Calibration of a Fast Neutron Collar for the Measurement of Fresh PWR Fuel Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swinhoe, Martyn Thomas; De Baere, Paul

2015-04-17

A new neutron collar has been designed for the measurement of fresh LEU fuel assemblies. This collar uses “fast mode” measurement to reduce the effect of burnable poison rods on the assay and thus reduce the dependence on the operator’s declaration. The new collar design reduces effect of poison rods considerably. Instead of 12 pins of 5.2% Gd causing a 20.4% effect, as in the standard thermal mode collar, they only cause a 3.2% effect in the new collar. However it has higher efficiency so that reasonably precise measurements can be made in 25 minutes, rather than the 1 hourmore » of previous collars. The new collar is fully compatible with the use of the standard data collection and analysis code INCC. This report describes the calibration that was made with a mock-up assembly at Los Alamos National Laboratory and with actual assemblies at the AREVA Fuel fabrication Plant in Lingen, Germany.« less

Carbon isotope chemostratigraphy and precise dating of middle Frasnian (lower Upper Devonian) Alamo Breccia, Nevada, USA

USGS Publications Warehouse

Morrow, J.R.; Sandberg, C.A.; Malkowski, K.; Joachimski, M.M.

2009-01-01

At Hancock Summit West, Nevada, western USA, uppermost Givetian (upper Middle Devonian) and lower and middle Frasnian (lower Upper Devonian) rocks of the lower Guilmette Formation include, in stratigraphic sequence, carbonate-platform facies of the conodont falsiovalis, transitans, and punctata Zones; the type Alamo Breccia Member of the middle punctata Zone; and slope facies of the punctata and hassi Zones. The catastrophically deposited Alamo Breccia and related phenomena record the ~ 382??Ma Alamo event, produced by a km-scale bolide impact into a marine setting seaward of an extensive carbonate platform fringing western North America. Re-evaluation of conodonts from the lower Guilmette Formation and Alamo Breccia Member, together with regional sedimentologic and conodont biofacies comparisons, now firmly locates the onset of the Johnson et al. (1985) transgressive-regressive (T-R) cycle IIc, which occurred after the start of the punctata Zone, within a parautochthonous megablock low in the Alamo Breccia. Whole-rock carbon isotope analyses through the lower Guilmette Formation and Alamo Breccia Member reveal two positive ??13Ccarb excursions: (1) a small, 3??? excursion, which is possibly correlative with the falsiovalis Event previously identified from sections in Western Europe and Australia, occurs below the breccia in the Upper falsiovalis Zone to early part of the transitans Zone; and (2) a large, multi-part excursion, dominated by a 6??? positive shift, begins above the start of the punctata Zone and onset of T-R cycle IIc and continues above the Alamo Breccia, ending near the punctata- hassi zonal boundary. This large excursion correlates with the punctata Event, a major positive ??13C excursion previously recognized in eastern Laurussia and northern Gondwana. Consistent with previous studies, at Hancock Summit West the punctata Event is apparently not associated with any regional extinctions or ecosystem reorganizations. In the study area, onset of the

CICE, The Los Alamos Sea Ice Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunke, Elizabeth; Lipscomb, William; Jones, Philip

The Los Alamos sea ice model (CICE) is the result of an effort to develop a computationally efficient sea ice component for a fully coupled atmosphere–land–ocean–ice global climate model. It was originally designed to be compatible with the Parallel Ocean Program (POP), an ocean circulation model developed at Los Alamos National Laboratory for use on massively parallel computers. CICE has several interacting components: a vertical thermodynamic model that computes local growth rates of snow and ice due to vertical conductive, radiative and turbulent fluxes, along with snowfall; an elastic-viscous-plastic model of ice dynamics, which predicts the velocity field of themore » ice pack based on a model of the material strength of the ice; an incremental remapping transport model that describes horizontal advection of the areal concentration, ice and snow volume and other state variables; and a ridging parameterization that transfers ice among thickness categories based on energetic balances and rates of strain. It also includes a biogeochemical model that describes evolution of the ice ecosystem. The CICE sea ice model is used for climate research as one component of complex global earth system models that include atmosphere, land, ocean and biogeochemistry components. It is also used for operational sea ice forecasting in the polar regions and in numerical weather prediction models.« less

The Los Alamos Supernova Light Curve Project: Current Projects and Future Directions

NASA Astrophysics Data System (ADS)

Wiggins, Brandon Kerry; Los Alamos Supernovae Research Group

2015-01-01

The Los Alamos Supernova Light Curve Project models supernovae in the ancient and modern universe to determine the luminosities of observability of certain supernovae events and to explore the physics of supernovae in the local universe. The project utilizes RAGE, Los Alamos' radiation hydrodynamics code to evolve the explosions of progenitors prepared in well-established stellar evolution codes. RAGE allows us to capture events such as shock breakout and collisions of ejecta with shells of material which cannot be modeled well in other codes. RAGE's dumps are then ported to LANL's SPECTRUM code which uses LANL's OPLIB opacities database to calculate light curves and spectra. In this paper, we summarize our recent work in modeling supernovae.

Amphibians and Reptiles of Los Alamos County

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

Visiting Scholars Program to Attract Brightest Minds | Poster

Cancer.gov

By Walter G. Hubert, Guest Writer National laboratories have a knack for assembling critical mass … and Frederick National Laboratory for Cancer Research, the newest kid on the block among such recognized research and development (R&D) leaders like Los Alamos, Oakridge, Sandia, and others, is just the place to bring together the brightest minds to take on the toughest

Portable MRI developed at Los Alamos

ScienceCinema

Espy, Michelle

2018-02-14

Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines just can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block. "SQUIDs are

Portable MRI developed at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espy, Michelle

Scientists at Los Alamos National Laboratory are developing an ultra-low-field Magnetic Resonance Imaging (MRI) system that could be low-power and lightweight enough for forward deployment on the battlefield and to field hospitals in the World's poorest regions. "MRI technology is a powerful medical diagnostic tool," said Michelle Espy, the Battlefield MRI (bMRI) project leader, "ideally suited for imaging soft-tissue injury, particularly to the brain." But hospital-based MRI devices are big and expensive, and require considerable infrastructure, such as large quantities of cryogens like liquid nitrogen and helium, and they typically use a large amount of energy. "Standard MRI machines justmore » can't go everywhere," said Espy. "Soldiers wounded in battle usually have to be flown to a large hospital and people in emerging nations just don't have access to MRI at all. We've been in contact with doctors who routinely work in the Third World and report that MRI would be extremely valuable in treating pediatric encephalopathy, and other serious diseases in children." So the Los Alamos team started thinking about a way to make an MRI device that could be relatively easy to transport, set up, and use in an unconventional setting. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make. Espy and her team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth's magnetic field. To achieve images at such low fields they use exquisitely sensitive detectors called Superconducting Quantum Interference Devices, or SQUIDs. SQUIDs are among the most sensitive magnetic field detectors available, so interference with the signal is the primary stumbling block

Sulfur activation at the Little Boy-Comet Critical Assembly: a replica of the Hiroshima bomb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerr, G.D.; Emery, J.F.; Pace, J.V. III

1985-04-01

Studies have been completed on the activation of sulfur by fast neutrons from the Little Boy-Comet Critical Assembly which replicates the general features of the Hiroshima bomb. The complex effects of the bomb's design and construction on leakage of sulfur-activation neutrons were investigated both experimentally and theoretically. Our sulfur activation studies were performed as part of a larger program to provide benchmark data for testing of methods used in recent source-term calculations for the Hiroshima bomb. Source neutrons capable of activating sulfur play an important role in determining neutron doses in Hiroshima at a kilometer or more from the pointmore » of explosion. 37 refs., 5 figs., 6 tabs.« less

Geohydrology and simulation of ground-water flow near Los Alamos, north-central New Mexico

USGS Publications Warehouse

Frenzel, P.F.

1995-01-01

An existing model was modified in recognition of new geohydrologic interpretations and adjusted to simulate hydrographs in well fields in the Los Alamos area. Hydraulic-head drawdowns at the Buckman well field resulting from two projected ground-water-withdrawal alternatives were estimated with the modified model. The Chaquehui formation (informal usage) is the main new feature of recent hydrologic interpretations for the Los Alamos area. The Chaquehui occupies a 'channel' that was eroded or faulted into the Tesuque Formation, and the Chaquehui is more permeable than the Tesuque. The Chaquehui is a major producing zone in the Pajarito Mesa well field and to a lesser extent in the Guaje well field. Model modification included splitting the four layers of the McAda-Wasiolek model (McAda, D.P., and Wasiolek, Maryann, 1988, Simulation of the regional geohydrology of the Tesuque aquifer system near Santa Fe, New Mexico: U.S. Geological Survey Water- Resources Investigations Report 87-4056, 71 p.) into eight layers to better simulate vertical ground-water movement. Other model modifications were limited as much as possible to the area of interest near Los Alamos and consisted mainly of adjusting hydraulic-conductivity values representing the Tesuque Formation, Chaquehui formation (informal usage), and Puye Formation, and adjusting simulated recharge along the Pajarito Fault Zone west of Los Alamos. Adjustments were based mainly on simulation of fluctuations in measured hydraulic heads near Los Alamos. Two possible alternative plans for replacing Guaje well field production were suggested by Los Alamos National Laboratory. In the first plan (Guaje alternative), the Guaje field would be renewed with four new wells replacing the existing production wells in the Guaje field. In the second plan (Pajarito-Otowi alternative), the Guaje well field would be retired and its former production would be made up by additional withdrawals from the Pajarito Mesa and Otowi well fields. A

The Los Alamos universe: Using multimedia to promote laboratory capabilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kindel, J.

2000-03-01

This project consists of a multimedia presentation that explains the technological capabilities of Los Alamos National Laboratory. It takes the form of a human-computer interface built around the metaphor of the universe. The project is intended promote Laboratory capabilities to a wide audience. Multimedia is simply a means of communicating information through a diverse set of tools--be they text, sound, animation, video, etc. Likewise, Los Alamos National Laboratory is a collection of diverse technologies, projects, and people. Given the ample material available at the Laboratory, there are tangible benefits to be gained by communicating across media. This paper consists ofmore » three parts. The first section provides some basic information about the Laboratory, its mission, and its needs. The second section introduces this multimedia presentation and the metaphor it is based on along with some basic concepts of color and user interaction used in the building of this project. The final section covers construction of the project, pitfalls, and future improvements.« less

Tritium concentrations in bees and honey at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fresquez, P.R.; Armstrong, D.R.; Salazar, J.G.

Los Alamos National Laboratory (LANL) has maintained a network of honey bee colonies at LANL, perimeter (Los Alamos townsite and White Rock/Pajarito Acres) and regional (background) areas for over 15 years; the main objective of this honey bee network was to help determine the bioavailability of certain radionuclides in the environment. Of all the radionuclides studied ({sup 3}H, {sup 57}Co, {sup 7}Be, {sup 22}Na, {sup 54}Mn, {sup 83}Rb, {sup 137}Cs, {sup 238}Pu, {sup 239}Pu, {sup 90}Sr and total U), tritium was consistently detected in bees and was most readily transferred to the honey. In fact, honey collected from hives locatedmore » at TA-21, TA-33, TA-50, TA-53, and TA-54 and from White Rock/Pajarito Acres contained significantly higher concentrations of {sup 3}H than regional background hives. Based on the average concentration of all radionuclides measured over the years, the effective dose equivalent (EDE) from consuming 5 kg (11 lb) of honey collected from Los Alamos (townsite) and White Rock/Pajarito Acres, after regional background has been subtracted, was 0.0186 ({+-}0.0507) and 0.0016 ({+-}0.0010) mrem/yr, respectively. The highest EDE, based on the mean + 2SD (95% confidence level), was 0.1200 mrem/y; this was <0.2% of the International Commission on Radiological Protection permissible dose limit of 100 mrem/yr from all pathways.« less

Rapid centriole assembly in Naegleria reveals conserved roles for both de novo and mentored assembly.

PubMed

Fritz-Laylin, Lillian K; Levy, Yaron Y; Levitan, Edward; Chen, Sean; Cande, W Zacheus; Lai, Elaine Y; Fulton, Chandler

2016-03-01

Centrioles are eukaryotic organelles whose number and position are critical for cilia formation and mitosis. Many cell types assemble new centrioles next to existing ones ("templated" or mentored assembly). Under certain conditions, centrioles also form without pre-existing centrioles (de novo). The synchronous differentiation of Naegleria amoebae to flagellates represents a unique opportunity to study centriole assembly, as nearly 100% of the population transitions from having no centrioles to having two within minutes. Here, we find that Naegleria forms its first centriole de novo, immediately followed by mentored assembly of the second. We also find both de novo and mentored assembly distributed among all major eukaryote lineages. We therefore propose that both modes are ancestral and have been conserved because they serve complementary roles, with de novo assembly as the default when no pre-existing centriole is available, and mentored assembly allowing precise regulation of number, timing, and location of centriole assembly. © 2016 Wiley Periodicals, Inc.

Examination of the home destruction in Los Alamos associated with the Cerro Grande Fire - July 10, 2000

Treesearch

Jack D. Cohen

2000-01-01

I arrived at Los Alamos on May 14, 2000 to conduct an examination of the home destruction associated with the Cerro Grande Fire. My examination occurred between the afternoon of 5/14 and late afternoon on 5/16. I had contact with the southern command post incident management team, the Los Alamos Fire Department, and the Santa Fe National Forest.The...

Differential Die-Away Instrument: Report on Fuel Assembly Mock-up Measurements with Neutron Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodsell, Alison Victoria; Swinhoe, Martyn Thomas; Henzl, Vladimir

2014-09-18

Fresh fuel experiments for the differential die-away (DDA) project were performed using a DT neutron generator, a 15x15 PWR fuel assembly, and nine 3He detectors in a water tank inside of a shielded cell at Los Alamos National Laboratory (LANL). Eight different fuel enrichments were created using low enriched (LEU) and depleted uranium (DU) dioxide fuel rods. A list-mode data acquisition system recorded the time-dependent signal and analysis of the DDA signal die-away time was performed. The die-away time depended on the amount of fissile material in the fuel assembly and the position of the detector. These experiments were performedmore » in support of the spent nuclear fuel Next Generation Safeguards Initiative DDA project. Lessons learned from the fresh fuel DDA instrument experiments and simulations will provide useful information to the spent fuel project.« less

Optical critical dimension metrology for directed self-assembly assisted contact hole shrink

NASA Astrophysics Data System (ADS)

Dixit, Dhairya; Green, Avery; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe E.; Keller, Nick; Race, Joseph; Chun, Jun Sung; O'Sullivan, Michael; Khare, Prasanna; Montgomery, Warren; Diebold, Alain C.

2016-01-01

Directed self-assembly (DSA) is a potential patterning solution for future generations of integrated circuits. Its main advantages are high pattern resolution (˜10 nm), high throughput, no requirement of high-resolution mask, and compatibility with standard fab-equipment and processes. The application of Mueller matrix (MM) spectroscopic ellipsometry-based scatterometry to optically characterize DSA patterned contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) is described. A regression-based approach is used to calculate the guide critical dimension (CD), DSA CD, height of the PS column, thicknesses of underlying layers, and contact edge roughness of the post PMMA etch DSA contact hole sample. Scanning electron microscopy and imaging analysis is conducted as a comparative metric for scatterometry. In addition, optical model-based simulations are used to investigate MM elements' sensitivity to various DSA-based contact hole structures, predict sensitivity to dimensional changes, and its limits to characterize DSA-induced defects, such as hole placement inaccuracy, missing vias, and profile inaccuracy of the PMMA cylinder.

Evaluation of the Pool Critical Assembly Benchmark with Explicitly-Modeled Geometry using MCNP6

DOE PAGES

Kulesza, Joel A.; Martz, Roger Lee

2017-03-01

Despite being one of the most widely used benchmarks for qualifying light water reactor (LWR) radiation transport methods and data, no benchmark calculation of the Oak Ridge National Laboratory (ORNL) Pool Critical Assembly (PCA) pressure vessel wall benchmark facility (PVWBF) using MCNP6 with explicitly modeled core geometry exists. As such, this paper provides results for such an analysis. First, a criticality calculation is used to construct the fixed source term. Next, ADVANTG-generated variance reduction parameters are used within the final MCNP6 fixed source calculations. These calculations provide unadjusted dosimetry results using three sets of dosimetry reaction cross sections of varyingmore » ages (those packaged with MCNP6, from the IRDF-2002 multi-group library, and from the ACE-formatted IRDFF v1.05 library). These results are then compared to two different sets of measured reaction rates. The comparison agrees in an overall sense within 2% and on a specific reaction- and dosimetry location-basis within 5%. Except for the neptunium dosimetry, the individual foil raw calculation-to-experiment comparisons usually agree within 10% but is typically greater than unity. Finally, in the course of developing these calculations, geometry that has previously not been completely specified is provided herein for the convenience of future analysts.« less

CHEMO/mechanical energy conversiona via supramolecular self-assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynn, David G.; Conticello, Vincent

With the assembly codes for protein/peptide self-assembly sufficiently developed to control these phases, we are positioned to address critical requirements for generating unique self-propagating functional assemblies such as chemical batteries and engines that can be used to extend the capability of living cells. These integrative functional assemblies can then be used within cells to create new functions that will address the world’s energy challenges.

The Los Alamos suite of relativistic atomic physics codes

DOE PAGES

Fontes, C. J.; Zhang, H. L.; Jr, J. Abdallah; ...

2015-05-28

The Los Alamos SuitE of Relativistic (LASER) atomic physics codes is a robust, mature platform that has been used to model highly charged ions in a variety of ways. The suite includes capabilities for calculating data related to fundamental atomic structure, as well as the processes of photoexcitation, electron-impact excitation and ionization, photoionization and autoionization within a consistent framework. These data can be of a basic nature, such as cross sections and collision strengths, which are useful in making predictions that can be compared with experiments to test fundamental theories of highly charged ions, such as quantum electrodynamics. The suitemore » can also be used to generate detailed models of energy levels and rate coefficients, and to apply them in the collisional-radiative modeling of plasmas over a wide range of conditions. Such modeling is useful, for example, in the interpretation of spectra generated by a variety of plasmas. In this work, we provide a brief overview of the capabilities within the Los Alamos relativistic suite along with some examples of its application to the modeling of highly charged ions.« less

Diversity in virus assembly: biology makes things complicated

NASA Astrophysics Data System (ADS)

Zlotnick, Adam

2008-03-01

Icosahedral viruses have an elegance of geometry that implies a general path of assembly. However, structure alone provides insufficient information. Cowpea Chlorotic Mottle Virus (CCMV), an important system for studying virus assembly, consists of 90 coat protein (CP) homodimers condensed around an RNA genome. The crystal structure (Speir et al, 1995) reveals that assembly causes burial of hydrophobic surface and formation of β hexamers, the intertwining of N-termini of the CPs surrounding a quasi-sixfold. This structural view leads to reasonable and erroneous predictions: (i) CCMV capsids are extremely stable, and (ii) β hexamer formation is critical to assembly. Experimentally, we have found that capsids are based on a network of extremely weak (4-5 kT) pairwise interactions and that pentamer formation is the critical step in assembly kinetics. Because of the fragility of CP-Cp interaction, we can redirect assembly to generate and dissociate tubular nanostructures. The dynamic behavior of CCMV reflects the requirements and peculiarities of an evolved biological system; it does not necessarily reflect the behavior predicted from a more static picture of the virus.

Visiting Scholars Program to Attract Brightest Minds | Poster

Cancer.gov

By Walter G. Hubert, Guest Writer National laboratories have a knack for assembling critical mass … and Frederick National Laboratory for Cancer Research, the newest kid on the block among such recognized research and development (R&D) leaders like Los Alamos, Oakridge, Sandia, and others, is just the place to bring together the brightest minds to take on the toughest challenges in cancer and AIDS research.

Structural performance of light-frame roof assemblies. I, Truss assemblies designed for high variability and wood failure

Treesearch

R.W. Wolfe; Monica McCarthy

1989-01-01

The first report of a three-part series that covers results of a full-scale roof assemblies research program. The focus of this report is the structural performance of truss assemblies comprising trusses with abnormally high stiffness variability and critical joint strength. Results discussed include properties of truss members and connections. individual truss...

Metagenomic Assembly: Overview, Challenges and Applications

PubMed Central

Ghurye, Jay S.; Cepeda-Espinoza, Victoria; Pop, Mihai

2016-01-01

Advances in sequencing technologies have led to the increased use of high throughput sequencing in characterizing the microbial communities associated with our bodies and our environment. Critical to the analysis of the resulting data are sequence assembly algorithms able to reconstruct genes and organisms from complex mixtures. Metagenomic assembly involves new computational challenges due to the specific characteristics of the metagenomic data. In this survey, we focus on major algorithmic approaches for genome and metagenome assembly, and discuss the new challenges and opportunities afforded by this new field. We also review several applications of metagenome assembly in addressing interesting biological problems. PMID:27698619

Proton Radiography at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saunders, Alexander

2017-02-28

The proton radiography (pRad) facility at Los Alamos National Lab uses high energy protons to acquire multiple frame flash radiographic sequences at megahertz speeds: that is, it can make movies of the inside of explosions as they happen. The facility is primarily used to study the damage to and failure of metals subjected to the shock forces of high explosives as well as to study the detonation of the explosives themselves. Applications include improving our understanding of the underlying physical processes that drive the performance of the nuclear weapons in the United States stockpile and developing novel armor technologies inmore » collaboration with the Army Research Lab. The principle and techniques of pRad will be described, and examples of some recent results will be shown.« less

Self-assembly of coiled coil peptides into nanoparticles vs 2-d plates: effects of assembly pathway

NASA Astrophysics Data System (ADS)

Kim, Kyunghee; Pochan, Darrin

Molecular solution assembly, or self-assembly, is a process by which ordered nanostructures or patterns are formed by non-covalent interactions during assembly. Biomimicry, the use of bioinspired molecules or biologically relevant materials, is an important area of self-assembly research with peptides serving a critical role as molecular tools. The morphology of peptide assemblies can be controlled by adjusting solution conditions such as the concentration of peptides, the temperature, and pH. Herein, spherical nanostructures, which have potential for creating an encapsulation system, are formed by self-assembly when coiled coil peptides are combined in solution. These peptides are homotrimeric and heterodimeric coiled-coil bundles and the homotrimer is connected with each of heterodimer through their external surfaces via disulfide bonds. The resultant covalent constructs could co-assemble into complementary trimeric hubs, respectively. The two peptide constructs are directly mixed and assembled in solution in order to produce either spherical particles or 2-d plates depending on the solution conditions and kinetic pathway of assembly. In particular, structural changes of the self-assembled peptides are explored by control of the thermal history of the assembly solution.

Review of Rover fuel element protective coating development at Los Alamos

NASA Technical Reports Server (NTRS)

Wallace, Terry C.

1991-01-01

The Los Alamos Scientific Laboratory (LASL) entered the nuclear propulsion field in 1955 and began work on all aspects of a nuclear propulsion program with a target exhaust temperature of about 2750 K. A very extensive chemical vapor deposition coating technology for preventing catastrophic corrosion of reactor core components by the high temperature, high pressure hydrogen propellant gas was developed. Over the 17-year term of the program, more than 50,000 fuel elements were coated and evaluated. Advances in performance were achieved only through closely coupled interaction between the developing fuel element fabrication and protective coating technologies. The endurance of fuel elements in high temperature, high pressure hydrogen environment increased from several minutes at 2000 K exit gas temperature to 2 hours at 2440 K exit gas temperature in a reactor test and 10 hours at 2350 K exit gas temperature in a hot gas test. The purpose of this paper is to highlight the rationale for selection of coating materials used (NbC and ZrC), identify critical fuel element-coat interactions that had to be modified to increase system performance, and review the evolution of protective coating technology.

Dissolved pesticides in the Alamo River and the Salton Sea, California, 1996-97

USGS Publications Warehouse

Crepeau, Kathryn L.; Kuivila, Kathryn; Bergamaschi, Brian A.

2002-01-01

Water samples were collected from the Alamo River and the Salton Sea, California, in autumn 1996 and late winter/early spring 1997 and analyzed for dissolved pesticides. The two seasons chosen for sampling were during pesticide application periods in the Imperial Valley. Pesticide concentrations were measured in filtered water samples using solid-phase extraction and analyzed by gas chromatography/mass spectrometry. Generally, the highest concentrations were measured in the Alamo River. The concentrations of carbaryl, chlorpyrifos, cycloate, dacthal, diazinon, and eptam were highest in samples collected in autumn 1996. In contrast, the concentrations of atrazine, carbofuran, and malathion were highest in samples collected in late winter/early spring 1997. The highest concentrations measured of atrazine, carbofuran, dacthal, eptam, and malathion all exceeded 1,000 nanograms per liter.

Los Alamos Scientific Laboratory energy-related history, research, managerial reorganization proposals, actions taken, and results. History report, 1945--1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammel, E.F.

1997-03-01

This report documents the development of major energy-related programs at the Los Alamos Scientific Laboratory between 1945 and 1979. Although the Laboratory`s primary mission during that era was the design and development of nuclear weapons and most of the Laboratory`s funding came from a single source, a number of factors were at work that led to the development of these other programs. Some of those factors were affected by the Laboratory`s internal management structure and organization; others were the result of increasing environmental awareness within the general population and the political consequences of that awareness; still others were related tomore » the increasing demand for energy and the increasing turmoil in the energy-rich Middle East. This report also describes the various activities in Los Alamos, in Washington, and in other areas of the world that contributed to the development of major energy-related programs at Los Alamos. The author has a unique historical perspective because of his involvement as a scientist and manager at the Los Alamos Scientific Laboratory during the time period described within the report. In addition, in numerous footnotes and references, he cites a large body of documents that include the opinions and perspectives of many others who were involved at one time or another in these programs. Finally the report includes a detailed chronology of geopolitical events that led to the development of energy-related programs at Los Alamos.« less

Critical seeding density improves properties and translatability of self-assembling anatomically shaped knee menisci

PubMed Central

Hadidi, Pasha; Yeh, Timothy C.; Hu, Jerry C.; Athanasiou, Kyriacos A.

2014-01-01

A recent development in the field of tissue engineering is the rise of all-biologic, scaffold-free engineered tissues. Since these biomaterials rely primarily upon cells, investigation of initial seeding densities constitutes a particularly relevant aim for tissue engineers. In this study, a scaffold-free method was used to create fibrocartilage in the shape of the rabbit knee meniscus. The objectives of this study were: (i) to determine the minimum seeding density, normalized by an area of 44 mm2, necessary for the self-assembling process of fibrocartilage to occur, (ii) examine relevant biomechanical properties of engineered fibrocartilage, such as tensile and compressive stiffness and strength, and their relationship to seeding density, and (iii) identify a reduced, or optimal, number of cells needed to produce this biomaterial. It was found that a decreased initial seeding density, normalized by the area of the construct, produced superior mechanical and biochemical properties. Collagen per wet weight, glycosaminoglycans per wet weight, tensile properties, and compressive properties were all significantly greater in the 5 million cells per construct group as compared to the historical 20 million cells per construct group. Scanning electron microscopy demonstrated that a lower seeding density results in a denser tissue. Additionally, the translational potential of the self-assembling process for tissue engineering was improved though this investigation, as fewer cells may be used in the future. The results of this study underscore the potential for critical seeding densities to be investigated when researching scaffold-free engineered tissues. PMID:25234157

An Analysis on the TEC Variability and Ionospheric Scintillation at Los Alamos, New Mexico Derived from FORTE-Received LAPP Signals

NASA Astrophysics Data System (ADS)

Huang, Z.; Roussel-Dupre, R.

2003-12-01

The total electron content (TEC) of ionosphere and its electron density irregularities (scintillation) have effects of degradation and disruption on radio signals passed between ground stations and orbiting man-made satellites. With the rapid increase in operational reliance on UHF/VHF satellite communication, it is desirable to obtain understandings of ionosphere TEC variability and scintillation characteristics to improve our ability of predicting satellite communication outages. In this work, data collected from FORTE satellite received LAPP (Los Alamos Portable Pulser) signals during 1998-2002 are used to derive TEC and ionospheric scintillation index at Los Alamos, New Mexico. To characterize in-situ TEC variability at Los Alamos, the FORTE-LAPP derived TECs are analyzed against diurnal, seasonal, solar activity, magnetic storm, and stratospheric warming. The results are also compared with the TEC estimates from the Los Alamos ionospheric transfer function (ITF) implemented with the global ionospheric models (IRI, PIM), and GPS -derived TEC maps. The FORTE-LAPP signals are also analyzed against two important measures of the effect of scintillation on broadband signals, the mean time delay and the time delay jitter. The results are used to examine coherence frequency bandwidth and compared with the predictions from a global scintillation model (WBMOD). The FORTE-LAPP analyzed and WBMOD predicted scintillation characteristics are used to investigate temporal and seasonal behavior of scintillation at Los Alamos.

Igniting the Light Elements: The Los Alamos Thermonuclear Weapon Project, 1942-1952

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzpatrick, Anne C.

1999-07-01

The American system of nuclear weapons research and development was conceived and developed not as a result of technological determinism, but by a number of individual architects who promoted the growth of this large technologically-based complex. While some of the technological artifacts of this system, such as the fission weapons used in World War II, have been the subject of many historical studies, their technical successors--fusion (or hydrogen) devices--are representative of the largely unstudied highly secret realms of nuclear weapons science and engineering. In the postwar period a small number of Los Alamos Scientific Laboratory's staff and affiliates were responsiblemore » for theoretical work on fusion weapons, yet the program was subject to both the provisions and constraints of the US Atomic Energy Commission, of which Los Alamos was a part. The Commission leadership's struggle to establish a mission for its network of laboratories, least of all to keep them operating, affected Los Alamos's leaders' decisions as to the course of weapons design and development projects. Adapting Thomas P. Hughes's ''large technological systems'' thesis, I focus on the technical, social, political, and human problems that nuclear weapons scientists faced while pursuing the thermonuclear project, demonstrating why the early American thermonuclear bomb project was an immensely complicated scientific and technological undertaking. I concentrate mainly on Los Alamos Scientific Laboratory's Theoretical, or T, Division, and its members' attempts to complete an accurate mathematical treatment of the ''Super''--the most difficult problem in physics in the postwar period--and other fusion weapon theories. Although tackling a theoretical problem, theoreticians had to address technical and engineering issues as well. I demonstrate the relative value and importance of H-bomb research over time in the postwar era to scientific, politician, and military participants in this project

Integrating Safety with Science,Technology and Innovation at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rich, Bethany M

2012-04-02

The mission of Los Alamos National Laboratory (LANL) is to develop and apply science, technology and engineering solutions to ensure the safety, security, and reliability of the U.S. nuclear deterrent; reduce global threats; and solve emerging national security challenges. The most important responsibility is to direct and conduct efforts to meet the mission with an emphasis on safety, security, and quality. In this article, LANL Environmental, Safety, and Health (ESH) trainers discuss how their application and use of a kinetic learning module (learn by doing) with a unique fall arrest system is helping to address one the most common industrialmore » safety challenges: slips and falls. A unique integration of Human Performance Improvement (HPI), Behavior Based Safety (BBS) and elements of the Voluntary Protection Program (VPP) combined with an interactive simulator experience is being used to address slip and fall events at Los Alamos.« less

Environmental surveillance at Los Alamos during 2005

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2006-09-30

Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (LANL or the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.IA, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory's efforts to ensure public safety and to monitor environmental quality atmore » and near the Laboratory. Chapter 1 provides an overview of the Laboratory's major environmental programs. Chapter 2 reports the Laboratory's compliance status for 2005. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, Air; Chapters 5 and 6, Water and Sediments; Chapter 7, Soils; and Chapter 8, Foodstuffs and Biota) in a format to meet the needs of a general and scientific audience. Chapter 9, new for this year, provides a summary of the status of environmental restoration work around LANL. A glossary and a list ofacronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory's technical areas and their associated programs, and Appendix D provides web links to more information.« less

Surface water data at Los Alamos National Laboratory: 2009 water year

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz, David; McCullough, Betsy

2010-05-01

The principal investigators collected and computed surface water discharge data from 73 stream-gage stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs— two that flow into Cañon de Valle and one that flows into Water Canyon.

Surface water data at Los Alamos National Laboratory: 2008 water year

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ortiz, David; Cata, Betsy; Kuyumjian, Gregory

2009-09-01

The principal investigators collected and computed surface water discharge data from 69 stream-gage stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs— two that flow into Cañon de Valle and one that flows into Water Canyon.

Fuels Inventories in the Los Alamos National Laboratory Region: 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balice, R.G.; Oswald, B.P.; Martin, C.

1999-03-01

Fifty-four sites were surveyed for fuel levels, vegetational structures, and topographic characteristics. Most of the surveyed sites were on Los Alamos National Laboratory property, however, some surveys were also conducted on U.S. Forest Service property. The overall vegetation of these sites ranged from pinon-juniper woodlands to ponderosa pine forests to mixed conifer forests, and the topographic positions included canyons, mesas, and mountains. The results of these surveys indicate that the understory fuels are the greatest in mixed conifer forests and that overstory fuels are greatest in both mixed conifer forests and ponderosa pine forests on mesas. The geographic distribution ofmore » these fuels would suggest a most credible wildfire scenario for the Los Alamos region. Three major fires have occurred since 1954 and these fires behaved in a manner that is consistent with this scenario. The most credible wildfire scenario was also supported by the results of BEHAVE modeling that used the fuels inventory data as inputs. Output from the BEHAVE model suggested that catastrophic wildfires would continue to occur during any season with sufficiently dry, windy weather.« less

Characterization of the CALIBAN Critical Assembly Neutron Spectra using Several Adjustment Methods Based on Activation Foils Measurement

NASA Astrophysics Data System (ADS)

Casoli, Pierre; Grégoire, Gilles; Rousseau, Guillaume; Jacquet, Xavier; Authier, Nicolas

2016-02-01

CALIBAN is a metallic critical assembly managed by the Criticality, Neutron Science and Measurement Department located on the French CEA Center of Valduc. The reactor is extensively used for benchmark experiments dedicated to the evaluation of nuclear data, for electronic hardening or to study the effect of the neutrons on various materials. Therefore CALIBAN irradiation characteristics and especially its central cavity neutron spectrum have to be very accurately evaluated. In order to strengthen our knowledge of this spectrum, several adjustment methods based on activation foils measurements are being studied for a few years in the laboratory. Firstly two codes included in the UMG package have been tested and compared: MAXED and GRAVEL. More recently, the CALIBAN cavity spectrum has been studied using CALMAR, a new adjustment tool currently under development at the CEA Center of Cadarache. The article will discuss and compare the results and the quality of spectrum rebuilding obtained with the UMG codes and with the CALMAR software, from a set of activation measurements carried out in the CALIBAN irradiation cavity.

Los Alamos National Laboratory Economic Analysis Capability Overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boero, Riccardo; Edwards, Brian Keith; Pasqualini, Donatella

Los Alamos National Laboratory has developed two types of models to compute the economic impact of infrastructure disruptions. FastEcon is a fast running model that estimates first-­order economic impacts of large scale events such as hurricanes and floods and can be used to identify the amount of economic activity that occurs in a specific area. LANL’s Computable General Equilibrium (CGE) model estimates more comprehensive static and dynamic economic impacts of a broader array of events and captures the interactions between sectors and industries when estimating economic impacts.

Hydrologic transport of depleted uranium associated with open air dynamic range testing at Los Alamos National Laboratory, New Mexico, and Eglin Air Force Base, Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, N.M.; Vanta, E.B.

Hydrologic investigations on depleted uranium fate and transport associated with dynamic testing activities were instituted in the 1980`s at Los Alamos National Laboratory and Eglin Air Force Base. At Los Alamos, extensive field watershed investigations of soil, sediment, and especially runoff water were conducted. Eglin conducted field investigations and runoff studies similar to those at Los Alamos at former and active test ranges. Laboratory experiments complemented the field investigations at both installations. Mass balance calculations were performed to quantify the mass of expended uranium which had transported away from firing sites. At Los Alamos, it is estimated that more thanmore » 90 percent of the uranium still remains in close proximity to firing sites, which has been corroborated by independent calculations. At Eglin, we estimate that 90 to 95 percent of the uranium remains at test ranges. These data demonstrate that uranium moves slowly via surface water, in both semi-arid (Los Alamos) and humid (Eglin) environments.« less

Refinements in the Los Alamos model of the prompt fission neutron spectrum

DOE PAGES

Madland, D. G.; Kahler, A. C.

2017-01-01

This paper presents a number of refinements to the original Los Alamos model of the prompt fission neutron spectrum and average prompt neutron multiplicity as derived in 1982. The four refinements are due to new measurements of the spectrum and related fission observables many of which were not available in 1982. Here, they are also due to a number of detailed studies and comparisons of the model with previous and present experimental results including not only the differential spectrum, but also integal cross sections measured in the field of the differential spectrum. The four refinements are (a) separate neutron contributionsmore » in binary fission, (b) departure from statistical equilibrium at scission, (c) fission-fragment nuclear level-density models, and (d) center-of-mass anisotropy. With these refinements, for the first time, good agreement has been obtained for both differential and integral measurements using the same Los Alamos model spectrum.« less

Surface Water Data at Los Alamos National Laboratory: 2002 Water Year

DOE Office of Scientific and Technical Information (OSTI.GOV)

D.A. Shaull; D. Ortiz; M.R. Alexander

2003-03-03

The principal investigators collected and computed surface water discharge data from 34 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data from 16 stations.

Surface Water Data at Los Alamos National Laboratory 2006 Water Year

DOE Office of Scientific and Technical Information (OSTI.GOV)

R.P. Romero, D. Ortiz, G. Kuyumjian

2007-08-01

The principal investigators collected and computed surface water discharge data from 44 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data for 44 stations.

Simplifying Complexity: Miriam Blake--Los Alamos National Laboratory Research Library, NM

ERIC Educational Resources Information Center

Library Journal, 2004

2004-01-01

The holy grail for many research librarians is one-stop searching: seamless access to all the library's resources on a topic, regardless of the source. Miriam Blake, Library Without Walls Project Leader at Los Alamos National laboratory (LANL), is making this vision a reality. Blake is part of a growing cadre of experts: a techie who is becoming a…

Steel pin and hanger assembly replacement options : final report.

DOT National Transportation Integrated Search

2017-01-01

A number of steel beam bridges exist in the United States that contain pin and hanger assemblies. Pin and hanger assemblies are fracture critical members whose failure would result in collapse of the bridge or render it unable to perform its expected...

Extracellular chloride signals collagen IV network assembly during basement membrane formation

PubMed Central

Cummings, Christopher F.; Pedchenko, Vadim; Brown, Kyle L.; Colon, Selene; Rafi, Mohamed; Jones-Paris, Celestial; Pokydeshava, Elena; Liu, Min; Pastor-Pareja, Jose C.; Stothers, Cody; Ero-Tolliver, Isi A.; McCall, A. Scott; Vanacore, Roberto; Bhave, Gautam; Santoro, Samuel; Blackwell, Timothy S.; Zent, Roy; Pozzi, Ambra

2016-01-01

Basement membranes are defining features of the cellular microenvironment; however, little is known regarding their assembly outside cells. We report that extracellular Cl− ions signal the assembly of collagen IV networks outside cells by triggering a conformational switch within collagen IV noncollagenous 1 (NC1) domains. Depletion of Cl− in cell culture perturbed collagen IV networks, disrupted matrix architecture, and repositioned basement membrane proteins. Phylogenetic evidence indicates this conformational switch is a fundamental mechanism of collagen IV network assembly throughout Metazoa. Using recombinant triple helical protomers, we prove that NC1 domains direct both protomer and network assembly and show in Drosophila that NC1 architecture is critical for incorporation into basement membranes. These discoveries provide an atomic-level understanding of the dynamic interactions between extracellular Cl− and collagen IV assembly outside cells, a critical step in the assembly and organization of basement membranes that enable tissue architecture and function. Moreover, this provides a mechanistic framework for understanding the molecular pathobiology of NC1 domains. PMID:27216258

BamA β16C strand and periplasmic turns are critical for outer membrane protein insertion and assembly.

PubMed

Gu, Yinghong; Zeng, Yi; Wang, Zhongshan; Dong, Changjiang

2017-11-21

Outer membrane (OM) β-barrel proteins play important roles in importing nutrients, exporting wastes and conducting signals in Gram-negative bacteria, mitochondria and chloroplasts. The outer membrane proteins (OMPs) are inserted and assembled into the OM by OMP85 family proteins. In Escherichia coli , the β-barrel assembly machinery (BAM) contains four lipoproteins such as BamB, BamC, BamD and BamE, and one OMP BamA, forming a 'top hat'-like structure. Structural and functional studies of the E. coli BAM machinery have revealed that the rotation of periplasmic ring may trigger the barrel β1C-β6C scissor-like movement that promote the unfolded OMP insertion without using ATP. Here, we report the BamA C-terminal barrel structure of Salmonella enterica Typhimurium str. LT2 and functional assays, which reveal that the BamA's C-terminal residue Trp, the β16C strand of the barrel and the periplasmic turns are critical for the functionality of BamA. These findings indicate that the unique β16C strand and the periplasmic turns of BamA are important for the outer membrane insertion and assembly. The periplasmic turns might mediate the rotation of the periplasmic ring to the scissor-like movement of BamA β1C-β6C, triggering the OMP insertion. These results are important for understanding the OMP insertion in Gram-negative bacteria, as well as in mitochondria and chloroplasts. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Resource Management Technology: Los Alamos Technical Capabilities for Emergency Management,

DTIC Science & Technology

1983-07-18

synthetic fuels from coal (analogous to the Fischer-Tropsch process), olefin polymerization, and flue - gas desulfurization . In order to successfully...world. It has been a major research effort here for decades. Also, in the area of desulfurization of flue gases, Los Alamos scientists have been...Tectonic and Geochemical Controls on Copper-Molybdenum Porphyry Mineralization in the Southwestern United States (M. J. Aldrich and A. W. Laughlin) 1.0.6

Los Alamos Canyon Ice Rink Parking Flood Plain Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hathcock, Charles Dean; Keller, David Charles

2015-02-10

The project location is in Los Alamos Canyon east of the ice rink facility at the intersection of West and Omega roads (Figure 1). Forty eight parking spaces will be constructed on the north and south side of Omega Road, and a lighted walking path will be constructed to the ice rink. Some trees will be removed during this action. A guardrail of approximately 400 feet will be constructed along the north side of West Road to prevent unsafe parking in that area.

Environmental surveillance at Los Alamos during 2008

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuehne, David; Gallagher, Pat; Hjeresen, Denny

2009-09-30

Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Programs Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at andmore » near the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information.« less

An organizational survey of the Los Alamos Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shurberg, D.A.; Haber, S.B.

An Organizational Survey (OS) was administered at the Los Alamos Site that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental, safety, and health concern, hazardous nature of work, safety and overall job satisfaction. The purpose of the OS is to measure in a quantitative and objective way the notion of culture;'' that is, the values, attitudes, and beliefs of the individuals working within the organization. In addition, through the OS, a broad sample of individuals can be reached that would probably not be interviewed or observed duringmore » the course of a typical assessment. The OS also provides a descriptive profile of the organization at one point in time that can then be compared to a profile taken at a different point in time to assess changes in the culture of the organization. While comparisons among groups are made, it is not the purpose of this report to make evaluative statements of which profile may be positive or negative. However, using the data presented in this report in conjunction with other evaluative activities, may provide useful insight into the organization. The OS administration at the Los Alamos Site was the ninth to occur at a Department of Energy (DOE) facility. All data from the OS is presented in group summaries, by organization, department or directorate within organization, supervisory level both overall and within organization, and staff classification within organization. Statistically significant differences between groups are identified and discussed. 9 refs., 94 figs., 11 tabs.« less

An organizational survey of the Los Alamos Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shurberg, D.A.; Haber, S.B.

An Organizational Survey (OS) was administered at the Los Alamos Site that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental, safety, and health concern, hazardous nature of work, safety and overall job satisfaction. The purpose of the OS is to measure in a quantitative and objective way the notion of ``culture;`` that is, the values, attitudes, and beliefs of the individuals working within the organization. In addition, through the OS, a broad sample of individuals can be reached that would probably not be interviewed or observed duringmore » the course of a typical assessment. The OS also provides a descriptive profile of the organization at one point in time that can then be compared to a profile taken at a different point in time to assess changes in the culture of the organization. While comparisons among groups are made, it is not the purpose of this report to make evaluative statements of which profile may be positive or negative. However, using the data presented in this report in conjunction with other evaluative activities, may provide useful insight into the organization. The OS administration at the Los Alamos Site was the ninth to occur at a Department of Energy (DOE) facility. All data from the OS is presented in group summaries, by organization, department or directorate within organization, supervisory level both overall and within organization, and staff classification within organization. Statistically significant differences between groups are identified and discussed. 9 refs., 94 figs., 11 tabs.« less

New geochronologic and stratigraphic evidence confirms the paleocene age of the dinosaur-bearing ojo alamo sandstone and animas formation in the San Juan Basin, New Mexico and Colorado

USGS Publications Warehouse

Fassett, J.E.

2009-01-01

Dinosaur fossils are present in the Paleocene Ojo Alamo Sandstone and Animas Formation in the San Juan Basin, New Mexico, and Colorado. Evidence for the Paleo-cene age of the Ojo Alamo Sandstone includes palynologic and paleomagnetic data. Palynologic data indicate that the entire Ojo Alamo Sandstone, including the lower dinosaur-bearing part, is Paleocene in age. All of the palynomorph-productive rock samples collected from the Ojo Alamo Sandstone at multiple localities lacked Creta-ceous index palynomorphs (except for rare, reworked specimens) and produced Paleocene index palynomorphs. Paleocene palynomorphs have been identified strati-graphically below dinosaur fossils at two separate localities in the Ojo Alamo Sand-stone in the central and southern parts of the basin. The Animas Formation in the Colorado part of the basin also contains dinosaur fossils, and its Paleocene age has been established based on fossil leaves and palynology. Magnetostratigraphy provides independent evidence for the Paleocene age of the Ojo Alamo Sandstone and its dinosaur-bearing beds. Normal-polarity magnetochron C29n (early Paleocene) has been identified in the Ojo Alamo Sandstone at six localities in the southern part of the San Juan Basin. An assemblage of 34 skeletal elements from a single hadrosaur, found in the Ojo Alamo Sandstone in the southern San Juan Basin, provided conclusive evidence that this assemblage could not have been reworked from underlying Cretaceous strata. In addition, geochemical studies of 15 vertebrate bones from the Paleocene Ojo Alamo Sandstone and 15 bone samples from the underlying Kirtland Formation of Late Creta-ceous (Campanian) age show that each sample suite contained distinctly different abundances of uranium and rare-earth elements, indicating that the bones were miner-alized in place soon after burial, and that none of the Paleocene dinosaur bones ana-lyzed had been reworked. ?? U.S. Geological Survey, Public Domain April 2009.

2 x 2 Polyethylene Reflected and Moderated Highly Enriched Uranium System with Rhenium

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Nichole Ellis; Jesson Hutchinson; John D. Bess

2010-09-01

The 2 × 2 array HEU-Re experiment was performed on the Planet universal critical assembly machine on November 4th, 2003 at the Los Alamos Critical Experiments Facility (LACEF) at Los Alamos National Laboratory (LANL). For this experiment, there were 10 ½ units, each full unit containing four HEU foils and two rhenium foils. The top unit contained only two HEU foils and two rhenium foils. A total of 42 HEU foils were used for this experiment. Rhenium is a desirable cladding material for space nuclear power applications. This experiment consisted of HEU foils interleaved with rhenium foils and is moderatedmore » and reflected by polyethylene plates. A unit consisted of a polyethylene plate, which has a recess for rhenium foils, and four HEU foils in a single layer in the top recess of each polyethylene plate. The Planet universal criticality assembly machine has been previously used in experiments containing HEU foils interspersed with SiO2 (HEU-MET-THERM-001), Al (HEU-MET-THERM-008), MgO (HEU-MET-THERM-009), Gd foils (HEU-MET-THERM-010), 2 × 2 × 26 Al (HEU-MET-THERM-012), Fe (HEU-MET-THERM-013 and HEU-MET-THERM-015), 2 × 2 × 23 SiO2 (HEU-MET-THERM-014), 2 × 2 × 11 hastalloy plates (HEU-MET-THERM-016), and concrete (HEU-MET-THERM-018). The 2 × 2 array of HEU-Re is considered acceptable for use as a benchmark critical experiment.« less

Scalable Directed Self-Assembly Using Ultrasound Waves

DTIC Science & Technology

2015-09-04

SECURITY CLASSIFICATION OF: We aim to understand how ultrasound waves can be used to create organized patterns of nanoparticles in a host medium such...as a polymer matrix material. The critical difference between the ultrasound technology studied in this project, and other directed self-assembly...of nanoparticles dispersed in a host medium are assembled by means of standing ultrasound waves. Additionally, we have obtained experimental

Francis Perrin's 1939 Analysis of Uranium Criticality

NASA Astrophysics Data System (ADS)

Reed, Cameron

2012-03-01

In May 1939, French physicist Francis Perrin published the first numerical estimate of the fast-neutron critical mass of a uranium compound. While his estimate of about 40 metric tons (12 tons if tamped) pertained to uranium oxide of natural isotopic composition as opposed to the enriched uranium that would be required for a nuclear weapon, it is interesting to examine Perrin's physics and to explore the subsequent impact of his paper. In this presentation I will discuss Perrin's model, the likely provenance of his parameter values, and how his work compared to the approach taken by Robert Serber in his 1943 Los Alamos Primer.

Environmental Assessment and Finding of No Significant Impact: The Proposed Issuance of an Easement to Public Service Company of New Mexico for the Construction and Operation of a 12-inch Natural Gas Pipeline within Los Alamos National Laboratory, Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

N /A

2002-07-30

installation. PNM would also construct and maintain a service road along the pipeline easement. In addition, when construction is complete, the easement would be reseeded. Portions of the Proposed Action are located within potential roosting and nesting habitat for the Mexican spotted owl (Strix occidentalis lucida), a Federally protected threatened species. Surveys over the last seven years have identified no owls within this area. The Proposed Action would be conducted according to the provisions of the LANL Threatened and Endangered Species Habitat Management Plan. Effects would not be adverse to either individuals or potential critical habitat for protected species. Cultural resources within the vicinity of the proposed easement would be avoided with the exception of an historic trail. However, the original trail has been affected by previous activities and no longer has sufficient historical value to be eligible for listing on the National Register of Historic Places. Minimal undisturbed areas would be involved in the Proposed Action. Most of the proposed easement follows an established ROW for the existing electrical power line. There are several potentially contaminated areas within Los Alamos Canyon; however, these areas would be avoided, where possible, or, if avoidance isn't possible or practicable under the Proposed Action, the contaminated areas would be sampled and remediated in accordance with New Mexico Environment Department requirements before construction.« less

Metal Ion-Assembled Micro-Collagen Heterotrimers

PubMed Central

LeBruin, Lyndelle Toni; Banerjee, Sunandan; O'Rourke, Bruce Delany; Case, Martin Ashley

2011-01-01

Collagen mimetic peptides (CMPs) provide critical insight into the assembly, stability and structure of the triple helical collagen protein. The majority of natural fibrous collagens are aab or abc heterotrimers, yet few examples of heterotrimeric CMPs have been reported. Previously CMP heterotrimers have only been accessible by total syntheses or by introducing complementary interstrand electrostatic or steric interactions. Here we describe an abc CMP heterotrimer in which each contributing CMP consists of only three amino acids: glycine, proline and 4-hydroxyproline. Assembly of the heterotrimeric triple helix is directed by a combination of metal-ion coordination to set the relative register of the CMPs, and minimization of valence frustration to direct heterotrimerization. Assembly of the four-component mixture is facile and extremely rapid, and equilibration to the abc heterotrimer occurs within a few hours at modestly elevated temperatures. The melting temperatures of the metal-assembled collagen trimers are higher by some 30 °C than the apopeptide assemblies. Two iterations of the design are described, and the outcomes suggest possibilities for designing self-assembling abc and abb heterotrimers. PMID:21590759

Nondeterministic self-assembly of two tile types on a lattice.

PubMed

Tesoro, S; Ahnert, S E

2016-04-01

Self-assembly is ubiquitous in nature, particularly in biology, where it underlies the formation of protein quaternary structure and protein aggregation. Quaternary structure assembles deterministically and performs a wide range of important functions in the cell, whereas protein aggregation is the hallmark of a number of diseases and represents a nondeterministic self-assembly process. Here we build on previous work on a lattice model of deterministic self-assembly to investigate nondeterministic self-assembly of single lattice tiles and mixtures of two tiles at varying relative concentrations. Despite limiting the simplicity of the model to two interface types, which results in 13 topologically distinct single tiles and 106 topologically distinct sets of two tiles, we observe a wide variety of concentration-dependent behaviors. Several two-tile sets display critical behaviors in the form of a sharp transition from bound to unbound structures as the relative concentration of one tile to another increases. Other sets exhibit gradual monotonic changes in structural density, or nonmonotonic changes, while again others show no concentration dependence at all. We catalog this extensive range of behaviors and present a model that provides a reasonably good estimate of the critical concentrations for a subset of the critical transitions. In addition, we show that the structures resulting from these tile sets are fractal, with one of two different fractal dimensions.

Los Alamos National Laboratory W76 Pit Tube Lifetime Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abeln, Terri G.

2012-04-25

A metallurgical study was requested as part of the Los Alamos National Laboratory (LANL) W76-1 life-extension program (LEP) involving a lifetime analysis of type 304 stainless steel pit tubes subject to repeat bending loads during assembly and disassembly operations at BWXT/Pantex. This initial test phase was completed during the calendar years of 2004-2006 and the report not issued until additional recommended tests could be performed. These tests have not been funded to this date and therefore this report is considered final. Tubes were reportedly fabricated according to Rocky Flats specification P14548 - Seamless Type 304 VIM/VAR Stainless Steel Tubing. Tubemore » diameter was specified as 0.125 inches and wall thickness as 0.028 inches. A heat treat condition is not specified and the hardness range specification can be characteristic of both 1/8 and 1/4 hard conditions. Properties of all tubes tested were within specification. Metallographic analysis could not conclusively determine a specified limit to number of bends allowable. A statistical analysis suggests a range of 5-7 bends with a 99.95% confidence limit. See the 'Statistical Analysis' section of this report. The initial phase of this study involved two separate sets of test specimens. The first group was part of an investigation originating in the ESA-GTS [now Gas Transfer Systems (W-7) Group]. After the bend cycle test parameters were chosen (all three required bends subjected to the same amount of bend cycles) and the tubes bent, the investigation was transferred to Terri Abeln (Metallurgical Science and Engineering) for analysis. Subsequently, another limited quantity of tubes became available for testing and were cycled with the same bending fixture, but with different test parameters determined by T. Abeln.« less

Growth promotion and colonization of switchgrass (Panicum virgatum) cv. Alamo by bacterial endophyte Burkholderia phytofirmans strain PsJN

PubMed Central

2012-01-01

Background Switchgrass is one of the most promising bioenergy crop candidates for the US. It gives relatively high biomass yield and can grow on marginal lands. However, its yields vary from year to year and from location to location. Thus it is imperative to develop a low input and sustainable switchgrass feedstock production system. One of the most feasible ways to increase biomass yields is to harness benefits of microbial endophytes. Results We demonstrate that one of the most studied plant growth promoting bacterial endophytes, Burkholderia phytofirmans strain PsJN, is able to colonize and significantly promote growth of switchgrass cv. Alamo under in vitro, growth chamber, and greenhouse conditions. In several in vitro experiments, the average fresh weight of PsJN-inoculated plants was approximately 50% higher than non-inoculated plants. When one-month-old seedlings were grown in a growth chamber for 30 days, the PsJN-inoculated Alamo plants had significantly higher shoot and root biomass compared to controls. Biomass yield (dry weight) averaged from five experiments was 54.1% higher in the inoculated treatment compared to non-inoculated control. Similar results were obtained in greenhouse experiments with transplants grown in 4-gallon pots for two months. The inoculated plants exhibited more early tillers and persistent growth vigor with 48.6% higher biomass than controls. We also found that PsJN could significantly promote growth of switchgrass cv. Alamo under sub-optimal conditions. However, PsJN-mediated growth promotion in switchgrass is genotype specific. Conclusions Our results show B. phytofirmans strain PsJN significantly promotes growth of switchgrass cv. Alamo under different conditions, especially in the early growth stages leading to enhanced production of tillers. This phenomenon may benefit switchgrass establishment in the first year. Moreover, PsJN significantly stimulated growth of switchgrass cv. Alamo under sub-optimal conditions

A Conversation with Robert F. Christy Part II

NASA Astrophysics Data System (ADS)

Lippincott, Sara

2006-12-01

Robert F. Christy, Institute Professor of Theoretical Physics Emeritus at Caltech, recalls his wartime work at Los Alamos on the critical assembly for the plutonium bomb (“the Christy bomb”); the Alamogordo test, July 16, 1945; the postwar concerns of ALAS (Association of Los Alamos Scientists); his brief return to the University of Chicago and move to Caltech; friendship with and later alienation from Edward Teller; work with Charles and Tommy Lauritsen and William A. Fowler in Caltech’s Kellogg Radiation Laboratory; Freeman Dyson’s Orion Project; work on the meson and RR Lyrae stars; fellowship at Cambridge University; 1950s Vista Project at Caltech; his opposition to the Strategic Defense Initiative; and his post-retirement work for the National Research Council’s Committee on Dosimetry and on inertial-confinement fusion.

Effect of a dual-purpose cask payload increment of spent fuel assemblies from VVER 1000 Bushehr Nuclear Power Plant on basket criticality.

PubMed

Rezaeian, M; Kamali, J

2017-01-01

Dual-purpose casks can be utilized for dry interim storage and transportation of the highly radioactive spent fuel assemblies (SFAs) of Bushehr Nuclear Power Plant (NPP). Criticality safety analysis was carried out using the MCNP code for the cask containing 12, 18, or 19 SFAs. The basket materials of borated stainless steel and Boral (Al-B 4 C) were investigated, and the minimum required receptacle pitch of the basket was determined. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct assembling methodologies for high-throughput bioscreening

PubMed Central

Rodríguez-Dévora, Jorge I.; Shi, Zhi-dong; Xu, Tao

2012-01-01

Over the last few decades, high-throughput (HT) bioscreening, a technique that allows rapid screening of biochemical compound libraries against biological targets, has been widely used in drug discovery, stem cell research, development of new biomaterials, and genomics research. To achieve these ambitions, scaffold-free (or direct) assembly of biological entities of interest has become critical. Appropriate assembling methodologies are required to build an efficient HT bioscreening platform. The development of contact and non-contact assembling systems as a practical solution has been driven by a variety of essential attributes of the bioscreening system, such as miniaturization, high throughput, and high precision. The present article reviews recent progress on these assembling technologies utilized for the construction of HT bioscreening platforms. PMID:22021162

Whiteness and Critical Pedagogy

ERIC Educational Resources Information Center

Allen, Ricky Lee

2004-01-01

The purpose of this article is to rethink critical pedagogy by imagining it from a race-radical perspective that owes its lineage to scholars like W. E. B. Du Bois. The author assembles a critical pedagogy that hopes to contribute to both the transformation of white identity and the abolition of white supremacy. He draws from the roots of critical…

Self-assembly of nanocomposite materials

DOEpatents

Brinker, C. Jeffrey; Sellinger, Alan; Lu, Yunfeng

2001-01-01

A method of making a nanocomposite self-assembly is provided where at least one hydrophilic compound, at least one hydrophobic compound, and at least one amphiphilic surfactant are mixed in an aqueous solvent with the solvent subsequently evaporated to form a self-assembled liquid crystalline mesophase material. Upon polymerization of the hydrophilic and hydrophobic compounds, a robust nanocomposite self-assembled material is formed. Importantly, in the reaction mixture, the amphiphilic surfactant has an initial concentration below the critical micelle concentration to allow formation of the liquid-phase micellar mesophase material. A variety of nanocomposite structures can be formed, depending upon the solvent evaporazation process, including layered mesophases, tubular mesophases, and a hierarchical composite coating composed of an isotropic worm-like micellar overlayer bonded to an oriented, nanolaminated underlayer.

Self assembly of rectangular shapes on concentration programming and probabilistic tile assembly models

PubMed Central

Rajasekaran, Sanguthevar

2013-01-01

Efficient tile sets for self assembling rectilinear shapes is of critical importance in algorithmic self assembly. A lower bound on the tile complexity of any deterministic self assembly system for an n × n square is Ω(log(n)log(log(n))) (inferred from the Kolmogrov complexity). Deterministic self assembly systems with an optimal tile complexity have been designed for squares and related shapes in the past. However designing Θ(log(n)log(log(n))) unique tiles specific to a shape is still an intensive task in the laboratory. On the other hand copies of a tile can be made rapidly using PCR (polymerase chain reaction) experiments. This led to the study of self assembly on tile concentration programming models. We present two major results in this paper on the concentration programming model. First we show how to self assemble rectangles with a fixed aspect ratio (α:β), with high probability, using Θ(α + β) tiles. This result is much stronger than the existing results by Kao et al. (Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008) and Doty (Randomized self-assembly for exact shapes. In: proceedings of the 50th annual IEEE symposium on foundations of computer science (FOCS), IEEE, Atlanta. pp 85–94, 2009)—which can only self assembly squares and rely on tiles which perform binary arithmetic. On the other hand, our result is based on a technique called staircase sampling. This technique eliminates the need for sub-tiles which perform binary arithmetic, reduces the constant in the asymptotic bound, and eliminates the need for approximate frames (Kao et al. Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008). Our second result applies staircase sampling on the equimolar concentration programming model (The tile complexity of linear assemblies. In: proceedings of the 36th international colloquium automata, languages and programming: Part I on ICALP ’09, Springer-Verlag, pp 235�

Self assembly of rectangular shapes on concentration programming and probabilistic tile assembly models.

PubMed

Kundeti, Vamsi; Rajasekaran, Sanguthevar

2012-06-01

Efficient tile sets for self assembling rectilinear shapes is of critical importance in algorithmic self assembly. A lower bound on the tile complexity of any deterministic self assembly system for an n × n square is [Formula: see text] (inferred from the Kolmogrov complexity). Deterministic self assembly systems with an optimal tile complexity have been designed for squares and related shapes in the past. However designing [Formula: see text] unique tiles specific to a shape is still an intensive task in the laboratory. On the other hand copies of a tile can be made rapidly using PCR (polymerase chain reaction) experiments. This led to the study of self assembly on tile concentration programming models. We present two major results in this paper on the concentration programming model. First we show how to self assemble rectangles with a fixed aspect ratio ( α:β ), with high probability, using Θ( α + β ) tiles. This result is much stronger than the existing results by Kao et al. (Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008) and Doty (Randomized self-assembly for exact shapes. In: proceedings of the 50th annual IEEE symposium on foundations of computer science (FOCS), IEEE, Atlanta. pp 85-94, 2009)-which can only self assembly squares and rely on tiles which perform binary arithmetic. On the other hand, our result is based on a technique called staircase sampling . This technique eliminates the need for sub-tiles which perform binary arithmetic, reduces the constant in the asymptotic bound, and eliminates the need for approximate frames (Kao et al. Randomized self-assembly for approximate shapes, LNCS, vol 5125. Springer, Heidelberg, 2008). Our second result applies staircase sampling on the equimolar concentration programming model (The tile complexity of linear assemblies. In: proceedings of the 36th international colloquium automata, languages and programming: Part I on ICALP '09, Springer-Verlag, pp 235

Radonuclide concentrations in bees and honey in the vicinity of Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fresquez, P.R.; Armstrong, D.R.

Honeybees are effective monitors of environmental pollution; they forage for P len and nectar over a large area ({congruent}7 km{sup 2}), accumulate contaminants from air, water, plants, and soil, and return to a fixed location (the hive) for sampling. Los Alamos National Laboratory (LANL), in fact, has maintained a network of honeybee colonies within and around LANL for 16 years (1979 to 1994); the objectives for maintaining this honeybee network were to (1) determine the bioavailability of radionuclides in the environment, and (2) the committed effective dose equivalent (CEDE) to people who may consume honey from these beehives (Los Alamosmore » and White Rock/Pajarito Acres lownsites). Of all the radionuclides studied over the years, tritium (314) was consistently picked up by the bees and was most readily transferred to the honey. Tritium in honey collected from hives located within LANL, for example, ranged in concentration from 0.07 Bq mL{sup -1} (1.9 pCi mL{sup -1}) to 27.75 Bq mL{sup -1} (749.9 pCi mL{sup -1}) (LANL Neutron Science Center); the average concentration of {sup 3}H in honey Collected from hives located around the LANL area (perimeter) ranged in concentration from 0.34 Bq mL{sup -1} (9.3 pCi mL{sup -1}) (White Rock/Pajarito Acres townsite) to 3.67 Bq mL{sup -1} (99.3 pCi mL{sup -1}) (Los Alamos townsite). Overall, the CEDE-based on the average concentration of all radionuclides measured over the years-from consuming 5 kg (11 lbs) of honey collected from hives located within the townsites of Los Alamos and White Rock/Pajarito Acres, after regional (background) as been subtracted, was 0.074 {mu}Sv y{sup -1} (0.0074 mrem y{sup -1}) and 0.024 pSv y{sup -1} (0.0024 mrem y{sup -1}), respectively. The highest CEDE, based on the mean + 2 standard deviations (95% confidence level), was 0.334 fiSv y{sup -1} (0.0334 mrem y{sup -1}) (Los Alamos townsitc).« less

Environmental Survey preliminary report, Los Alamos National Laboratory, Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-01-01

This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy's (DOE) Los Alamos National Laboratory (LANL), conducted March 29, 1987 through April 17, 1987. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are outside experts being supplied by a private contractor. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with the LANL. The Survey covers all environmental media andmore » all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. The on-site phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at the LANL, and interviews with site personnel. The Survey team developed Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during its on-site activities. The Sampling and Analysis Plan will be executed by the Idaho National Engineering Laboratory. When completed, the results will be incorporated into the LANL Environmental Survey Interim Report. The Interim Report will reflect the final determinations of the Survey for the LANL. 65 refs., 68 figs., 73 tabs.« less

Stormwater Pollution Prevention Plan for the TA-60-02 Salvage Warehouse, Los Alamos National Laboratory, Revision 3, January 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgin, Jillian Elizabeth

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector P-Land Transportation and Warehousing as a guide. The applicable stormwater discharge permit is EPA General Permit Registration Number NMR053915 (Los Alamos National Security (LANS) (U.S. EPA, June 2015). Contents of the Junemore » 4, 2015 Multi-sector General Permit can be viewed at: https://www.epa.gov/sites/production/files/2015- 10/documents/msgp2015_finalpermit.pdf This SWPPP applies to discharges of stormwater from the operational areas of the TA-60-02 Salvage and Warehouse facility at Los Alamos National Laboratory. Los Alamos National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-60-02 Salvage/ Warehouse and associated areas. The current permit expires at midnight on June 4, 2020. A copy of the facility NOI and LANS Delegation of Authority Letter are located in Appendix C of this SWPPP.« less

Environmental surveillance at Los Alamos during 2009

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuehne, David; Poff, Ben; Hjeresen, Denny

2010-09-30

Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) environmental organization, as required by US Department of Energy Order 5400.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and nearmore » the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2009. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (air in Chapter 4; water and sediments in Chapters 5 and 6; soils in Chapter 7; and foodstuffs and biota in Chapter 8) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. The new Chapter 10 describes the Laboratory’s environmental stewardship efforts and provides an overview of the health of the Rio Grande. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the Laboratory�

Environmental surveillance at Los Alamos during 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohen, K.; Stoker, A.; Stone, G.

1994-07-01

This report describes the environmental surveillance program at Los Alamos National Laboratory during 1992. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring results to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1992 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Using comparisons with standards, regulations,more » and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, laboratory employees, or the environment.« less

TOPAZ II Anti-Criticality Device Rapid Prototype

NASA Astrophysics Data System (ADS)

Campbell, Donald R.; Otting, William D.

1994-07-01

The Ballistic Missile Defense Organization (BMDO) has been working on a Nuclear Electric Propulsion Space Test Project (NEPSTP) using an existing Russian Topaz II reactor system to power the NEPSTP satellite. Safety investigations have shown that it will be possible to safely launch the Topaz II system in the United States with some modification to preclude water flooded criticality. A ``fuel-out'' water subcriticality concept was selected by the Los Alamos National Laboratory (LANL) as the baseline concept. A fuel-out anti-criticality device (ACD) conceptual design was developed by Rockwell. The concept functions to hold the fuel from the four centermost thermionic fuel elements (TFEs) outside the reactor during launch and reliably inserts the fuel into the reactor once the operational orbit is achieved. A four-tenths scale ACD rapid prototype model, fabricated from the CATIA solids design model, clearly shows in three dimensions the relative size and spatial relationship of the ACD components.

Summary of ORSphere critical and reactor physics measurements

NASA Astrophysics Data System (ADS)

Marshall, Margaret A.; Bess, John D.

2017-09-01

In the early 1970s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950s. The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVA I experiments. This critical configuration has been evaluated. Preliminary results were presented at ND2013. Since then, the evaluation was finalized and judged to be an acceptable benchmark experiment for the International Criticality Safety Benchmark Experiment Project (ICSBEP). Additionally, reactor physics measurements were performed to determine surface button worths, central void worth, delayed neutron fraction, prompt neutron decay constant, fission density and neutron importance. These measurements have been evaluated and found to be acceptable experiments and are discussed in full detail in the International Handbook of Evaluated Reactor Physics Benchmark Experiments. The purpose of this paper is to summarize all the evaluated critical and reactor physics measurements evaluations.

Critical Contribution of Tyr15 in the HIV-1 Integrase (IN) in Facilitating IN Assembly and Nonenzymatic Function through the IN Precursor Form with Reverse Transcriptase.

PubMed

Takahata, Tatsuro; Takeda, Eri; Tobiume, Minoru; Tokunaga, Kenzo; Yokoyama, Masaru; Huang, Yu-Lun; Hasegawa, Atsuhiko; Shioda, Tatsuo; Sato, Hironori; Kannagi, Mari; Masuda, Takao

2017-01-01

sites targeted by INSTI, have been discovered. Importantly, ALLINIs affect the nonenzymatic role(s) of HIV-1 IN, providing a rationale for the development of next-generation IN inhibitors with a mechanism that is distinct from that of INSTI. Here, we demonstrate that Tyr15 in the HIV-1 IN NTD plays a critical role during IN assembly by facilitating the hydrophobic interaction of the NTD with the other domains of IN. Importantly, we found that the functional assembly of IN through its fusion form with RT is critical for IN to exert its nonenzymatic function. Our results provide a novel mechanistic insight into the nonenzymatic function of HIV-1 IN and its prevention. Copyright © 2016 American Society for Microbiology.

A Handbook for Derivative Classifiers at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinkula, Barbara Jean

The Los Alamos Classification Office (within the SAFE-IP group) prepared this handbook as a resource for the Laboratory’s derivative classifiers (DCs). It contains information about United States Government (USG) classification policy, principles, and authorities as they relate to the LANL Classification Program in general, and to the LANL DC program specifically. At a working level, DCs review Laboratory documents and material that are subject to classification review requirements, while the Classification Office provides the training and resources for DCs to perform that vital function.

Fuel assembly design for APR1400 with low CBC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hah, Chang Joo, E-mail: changhah@kings.ac.kr

2015-04-29

APR 1400 is a PWR (Pressurized Water Reactor) with rated power of 3983 MWth and 241 assemblies. Recently, demand for extremely longer cycle up to 24 months is increasing with challenge of higher critical boron concentration (CBC). In this paper, assembly design method of selecting Gd-rods is introduced to reduce CBC. The purpose of the method is to lower the critical boron concentration of the preliminary core loading pattern (PLP), and consequently to achieve more negative or less positive moderator temperature coefficient (MTC). In this method, both the ratio of the number of low-Gd rod to the number of high-Gdmore » rod (r) and assembly average Gd wt% (w) are the decision variables. The target function is the amount of soluble boron concentration reduction, which can be converted to Δk{sub TARGET}. A set of new designed fuel assembly satisfies an objective function, min [f=∑{sub i}(Δk{sub FA}−Δk{sub i})], and enables a final loading pattern to reach a target CBC. The constraints required to determine a set of Δk are physically realizable pair, (r,w), and the sum of Δk of new designed assemblies as close to Δk{sub TARGET} as possible. New Gd-bearing assemblies selected based on valid pairs of (r,w) are replaced with existing assemblies in a PLP. This design methodology is applied to Shin-Kori Unit 3 Cycle 1 used as a reference model. CASMO-3/MASTER code is used for depletion calculation. CASMO-3/MASTER calculations with new designed assemblies produce lower CBC than the expected CBC, proving that the proposed method works successful.« less

Self-assembly micro optical filter

NASA Astrophysics Data System (ADS)

Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

2006-01-01

Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

Destructive analysis capabilities for plutonium and uranium characterization at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tandon, Lav; Kuhn, Kevin J; Drake, Lawrence R

Los Alamos National Laboratory's (LANL) Actinide Analytical Chemistry (AAC) group has been in existence since the Manhattan Project. It maintains a complete set of analytical capabilities for performing complete characterization (elemental assay, isotopic, metallic and non metallic trace impurities) of uranium and plutonium samples in different forms. For a majority of the customers there are strong quality assurance (QA) and quality control (QC) objectives including highest accuracy and precision with well defined uncertainties associated with the analytical results. Los Alamos participates in various international and national programs such as the Plutonium Metal Exchange Program, New Brunswick Laboratory's (NBL' s) Safeguardsmore » Measurement Evaluation Program (SME) and several other inter-laboratory round robin exercises to monitor and evaluate the data quality generated by AAC. These programs also provide independent verification of analytical measurement capabilities, and allow any technical problems with analytical measurements to be identified and corrected. This presentation will focus on key analytical capabilities for destructive analysis in AAC and also comparative data between LANL and peer groups for Pu assay and isotopic analysis.« less

Critical factors for assembling a high volume of DNA barcodes

PubMed Central

Hajibabaei, Mehrdad; deWaard, Jeremy R; Ivanova, Natalia V; Ratnasingham, Sujeevan; Dooh, Robert T; Kirk, Stephanie L; Mackie, Paula M; Hebert, Paul D.N

2005-01-01

Large-scale DNA barcoding projects are now moving toward activation while the creation of a comprehensive barcode library for eukaryotes will ultimately require the acquisition of some 100 million barcodes. To satisfy this need, analytical facilities must adopt protocols that can support the rapid, cost-effective assembly of barcodes. In this paper we discuss the prospects for establishing high volume DNA barcoding facilities by evaluating key steps in the analytical chain from specimens to barcodes. Alliances with members of the taxonomic community represent the most effective strategy for provisioning the analytical chain with specimens. The optimal protocols for DNA extraction and subsequent PCR amplification of the barcode region depend strongly on their condition, but production targets of 100K barcode records per year are now feasible for facilities working with compliant specimens. The analysis of museum collections is currently challenging, but PCR cocktails that combine polymerases with repair enzyme(s) promise future success. Barcode analysis is already a cost-effective option for species identification in some situations and this will increasingly be the case as reference libraries are assembled and analytical protocols are simplified. PMID:16214753

Peptide self-assembly: thermodynamics and kinetics.

PubMed

Wang, Juan; Liu, Kai; Xing, Ruirui; Yan, Xuehai

2016-10-21

Self-assembling systems play a significant role in physiological functions and have therefore attracted tremendous attention due to their great potential for applications in energy, biomedicine and nanotechnology. Peptides, consisting of amino acids, are among the most popular building blocks and programmable molecular motifs. Nanostructures and materials assembled using peptides exhibit important potential for green-life new technology and biomedical applications mostly because of their bio-friendliness and reversibility. The formation of these ordered nanostructures pertains to the synergistic effect of various intermolecular non-covalent interactions, including hydrogen-bonding, π-π stacking, electrostatic, hydrophobic, and van der Waals interactions. Therefore, the self-assembly process is mainly driven by thermodynamics; however, kinetics is also a critical factor in structural modulation and function integration. In this review, we focus on the influence of thermodynamic and kinetic factors on structural assembly and regulation based on different types of peptide building blocks, including aromatic dipeptides, amphiphilic peptides, polypeptides, and amyloid-relevant peptides.

Initial condition of stochastic self-assembly

NASA Astrophysics Data System (ADS)

Davis, Jason K.; Sindi, Suzanne S.

2016-02-01

The formation of a stable protein aggregate is regarded as the rate limiting step in the establishment of prion diseases. In these systems, once aggregates reach a critical size the growth process accelerates and thus the waiting time until the appearance of the first critically sized aggregate is a key determinant of disease onset. In addition to prion diseases, aggregation and nucleation is a central step of many physical, chemical, and biological process. Previous studies have examined the first-arrival time at a critical nucleus size during homogeneous self-assembly under the assumption that at time t =0 the system was in the all-monomer state. However, in order to compare to in vivo biological experiments where protein constituents inherited by a newly born cell likely contain intermediate aggregates, other possibilities must be considered. We consider one such possibility by conditioning the unique ergodic size distribution on subcritical aggregate sizes; this least-informed distribution is then used as an initial condition. We make the claim that this initial condition carries fewer assumptions than an all-monomer one and verify that it can yield significantly different averaged waiting times relative to the all-monomer condition under various models of assembly.

A history of the working group to address Los Alamos community health concerns - A case study of community involvement and risk communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harry Otway; Jon Johnson

2000-01-01

In May 1991, at a Department of Energy (DOE) public hearing at Los Alamos, New Mexico, a local artist claimed there had been a recent brain tumor cluster in a small Los Alamos neighborhood. He suggested the cause was radiation from past operations of Los Alamos National Laboratory. Data from the Laboratory's extensive environmental monitoring program gave no reason to believe this charge to be true but also could not prove it false. These allegations, reported in the local and regional media, alarmed the community and revealed an unsuspected lack of trust in the Laboratory. Having no immediate and definitivemore » response, the Laboratory offered to collaborate with the community to address this concern. The Los Alamos community accepted this offer and a joint Community-Laboratory Working Group met for the first time 29 days later. The working group set as its primary goal the search for possible carcinogens in the local environment. Meanwhile, the DOE announced its intention to fund the New Mexico Department of Health to perform a separate and independent epidemiological study of all Los Alamos cancer rates. In early 1994, after commissioning 17 environmental studies and meeting 34 times, the working group decided that the public health concerns had been resolved to the satisfaction of the community and voted to disband. This paper tells the story of the artist and the working group, and how the media covered their story. It summarizes the environmental studies directed by the working group and briefly reviews the main findings of the epidemiology study. An epilogue records the present-day recollections of some of the key players in this environmental drama.« less

Bradbury science museum: your window to Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deck, Linda Theresa

The Bradbury Science Museum is the public's window to Los Alamos National Laboratory and supports the Community Program Office's mission to develop community support to accomplish LANL's national security and science mission. It does this by stimulating interest in and increasing basic knowledge of science and technology in northern New Mexico audiences, and increasing public understanding and appreciation of how LANL science and technology solve our global problems. In performing these prime functions, the Museum also preserves the history of scientific accomplishment at the Lab by collecting and preserving artifacts of scientific and historical importance.

Environmental surveillance at Los Alamos during 1987

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1988-05-01

This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1987. Routine monitoring for radiation and radioactive or chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1987 cover: external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface and ground waters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriatemore » standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are insignificant and do not pose a threat to the public, Laboratory employees, or the environment. 113 refs., 33 figs., 120 tabs.« less

Environmental surveillance at Los Alamos during 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-10-01

This report describes the environmental surveillance program at Los Alamos National Laboratory (LANL or the Laboratory) during 1995. The Laboratory routinely monitors for radiation and for radioactive and nonradioactive materials at (or on) Laboratory sites as well as in the surrounding region. LANL uses the monitoring result to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1995 to assess external penetrating radiation; quantities of airborne emissions and liquid effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Usingmore » comparisons with standards, regulations, and background levels, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, Laboratory employees, or the environment.« less

Los Alamos Plutonium Facility Waste Management System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, K.; Montoya, A.; Wieneke, R.

1997-02-01

This paper describes the new computer-based transuranic (TRU) Waste Management System (WMS) being implemented at the Plutonium Facility at Los Alamos National Laboratory (LANL). The Waste Management System is a distributed computer processing system stored in a Sybase database and accessed by a graphical user interface (GUI) written in Omnis7. It resides on the local area network at the Plutonium Facility and is accessible by authorized TRU waste originators, count room personnel, radiation protection technicians (RPTs), quality assurance personnel, and waste management personnel for data input and verification. Future goals include bringing outside groups like the LANL Waste Management Facilitymore » on-line to participate in this streamlined system. The WMS is changing the TRU paper trail into a computer trail, saving time and eliminating errors and inconsistencies in the process.« less

2013 Los Alamos National Laboratory Hazardous Waste Minimization Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salzman, Sonja L.; English, Charles J.

2015-08-24

Waste minimization and pollution prevention are inherent goals within the operating procedures of Los Alamos National Security, LLC (LANS). The US Department of Energy (DOE) and LANS are required to submit an annual hazardous waste minimization report to the New Mexico Environment Department (NMED) in accordance with the Los Alamos National Laboratory (LANL or the Laboratory) Hazardous Waste Facility Permit. The report was prepared pursuant to the requirements of Section 2.9 of the LANL Hazardous Waste Facility Permit. This report describes the hazardous waste minimization program (a component of the overall Waste Minimization/Pollution Prevention [WMin/PP] Program) administered by the Environmentalmore » Stewardship Group (ENV-ES). This report also supports the waste minimization and pollution prevention goals of the Environmental Programs Directorate (EP) organizations that are responsible for implementing remediation activities and describes its programs to incorporate waste reduction practices into remediation activities and procedures. LANS was very successful in fiscal year (FY) 2013 (October 1-September 30) in WMin/PP efforts. Staff funded four projects specifically related to reduction of waste with hazardous constituents, and LANS won four national awards for pollution prevention efforts from the National Nuclear Security Administration (NNSA). In FY13, there was no hazardous, mixedtransuranic (MTRU), or mixed low-level (MLLW) remediation waste generated at the Laboratory. More hazardous waste, MTRU waste, and MLLW was generated in FY13 than in FY12, and the majority of the increase was related to MTRU processing or lab cleanouts. These accomplishments and analysis of the waste streams are discussed in much more detail within this report.« less

Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides.

PubMed

Weitzhandler, Isaac; Dzuricky, Michael; Hoffmann, Ingo; Garcia Quiroz, Felipe; Gradzielski, Michael; Chilkoti, Ashutosh

2017-08-14

Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

Efficacy of Alamo for prophylactic and therapeutic treatment of oak wilt in red oaks, 2004

Treesearch

K. Ward; J. Juzwik; S. Bernick

2004-01-01

An experiment (prophylactic study) to determine the efficacy of Alamo in preventing spread of C. fagacearum through grafted roots of oak wilt-affected and of apparently healthy red oaks was initiated in eight locations in east-central and southeastern Minnesota in Jul 2002.

Criticality Safety Evaluation for the TACS at DAF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Percher, C. M.; Heinrichs, D. P.

2011-06-10

Hands-on experimental training in the physical behavior of multiplying systems is one of ten key areas of training required for practitioners to become qualified in the discipline of criticality safety as identified in DOE-STD-1135-99, Guidance for Nuclear Criticality Safety Engineer Training and Qualification. This document is a criticality safety evaluation of the training activities and operations associated with HS-3201-P, Nuclear Criticality 4-Day Training Course (Practical). This course was designed to also address the training needs of nuclear criticality safety professionals under the auspices of the NNSA Nuclear Criticality Safety Program1. The hands-on, or laboratory, portion of the course will utilizemore » the Training Assembly for Criticality Safety (TACS) and will be conducted in the Device Assembly Facility (DAF) at the Nevada Nuclear Security Site (NNSS). The training activities will be conducted by Lawrence Livermore National Laboratory following the requirements of an Integrated Work Sheet (IWS) and associated Safety Plan. Students will be allowed to handle the fissile material under the supervision of an LLNL Certified Fissile Material Handler.« less

Autonomous Assembly of Modular Structures in Space and on Extraterrestrial Locations

NASA Astrophysics Data System (ADS)

Alhorn, Dean C.

2005-02-01

The new U.S. National Vision for Space Exploration requires many new enabling technologies to accomplish the goals of space commercialization and returning humans to the moon and extraterrestrial environments. Traditionally, flight elements are complete sub-systems requiring humans to complete the integration and assembly. These bulky structures also require the use of heavy launch vehicles to send the units to a desired location. This philosophy necessitates a high degree of safety, numerous space walks at a significant cost. Future space mission costs must be reduced and safety increased to reasonably achieve exploration goals. One proposed concept is the autonomous assembly of space structures. This concept is an affordable, reliable solution to in-space and extraterrestrial assembly. Assembly is autonomously performed when two components join after determining that specifications are correct. Local sensors continue monitor joint integrity post assembly, which is critical for safety and structural reliability. Achieving this concept requires a change in space structure design philosophy and the development of innovative technologies to perform autonomous assembly. Assembly of large space structures will require significant numbers of integrity sensors. Thus simple, low-cost sensors are integral to the success of this concept. This paper addresses these issues and proposes a novel concept for assembling space structures autonomously. Core technologies required to achieve in space assembly are presented. These core technologies are critical to the goal of utilizing space in a cost efficient and safe manner. Additionally, these novel technologies can be applied to other systems both on earth and extraterrestrial environments.

Autonomous Assembly of Modular Structures in Space and on Extraterrestrial Locations

NASA Technical Reports Server (NTRS)

Alhorn, Dean C.

2005-01-01

The new U.S. National Vision for Space Exploration requires many new enabling technologies to accomplish the goals of space commercialization and returning humans to the moon and extraterrestrial environments. Traditionally, flight elements are complete subsystems requiring humans to complete the integration and assembly. These bulky structures also require the use of heavy launch vehicles to send the units to a desired location. This philosophy necessitates a high degree of safety, numerous space walks at a significant cost. Future space mission costs must be reduced and safety increased to reasonably achieve exploration goals. One proposed concept is the autonomous assembly of space structures. This concept is an affordable, reliable solution to in-space and extraterrestrial assembly. Assembly is autonomously performed when two components join after determining that specifications are correct. Local sensors continue monitor joint integrity post assembly, which is critical for safety and structural reliability. Achieving this concept requires a change in space structure design philosophy and the development of innovative technologies to perform autonomous assembly. Assembly of large space structures will require significant numbers of integrity sensors. Thus simple, low-cost sensors are integral to the success of this concept. This paper addresses these issues and proposes a novel concept for assembling space structures autonomously. Core technologies required to achieve in space assembly are presented. These core technologies are critical to the goal of utilizing space in a cost efficient and safe manner. Additionally, these novel technologies can be applied to other systems both on earth and extraterrestrial environments.

Development of an Advanced Recycle Filter Tank Assembly for the ISS Urine Processor Assembly

NASA Technical Reports Server (NTRS)

Link, Dwight E., Jr.; Carter, Donald Layne; Higbie, Scott

2010-01-01

Recovering water from urine is a process that is critical to supporting larger crews for extended missions aboard the International Space Station. Urine is collected, preserved, and stored for processing into water and a concentrated brine solution that is highly toxic and must be contained to avoid exposure to the crew. The brine solution is collected in an accumulator tank, called a Recycle Filter Tank Assembly (RFTA) that must be replaced monthly and disposed in order to continue urine processing operations. In order to reduce resupply requirements, a new accumulator tank is being developed that can be emptied on orbit into existing ISS waste tanks. The new tank, called the Advanced Recycle Filter Tank Assembly (ARFTA) is a metal bellows tank that is designed to collect concentrated brine solution and empty by applying pressure to the bellows. This paper discusses the requirements and design of the ARFTA as well as integration into the urine processor assembly.

Environmental assessment for effluent reduction, Los Alamos National Laboratory, Los Alamos, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-09-11

The Department of Energy (DOE) proposes to eliminate industrial effluent from 27 outfalls at Los Alamos National Laboratory (LANL). The Proposed Action includes both simple and extensive plumbing modifications, which would result in the elimination of industrial effluent being released to the environment through 27 outfalls. The industrial effluent currently going to about half of the 27 outfalls under consideration would be rerouted to LANL`s sanitary sewer system. Industrial effluent from other outfalls would be eliminated by replacing once-through cooling water systems with recirculation systems, or, in a few instances, operational changes would result in no generation of industrial effluent.more » After the industrial effluents have been discontinued, the affected outfalls would be removed from the NPDES Permit. The pipes from the source building or structure to the discharge point for the outfalls may be plugged, or excavated and removed. Other outfalls would remain intact and would continue to discharge stormwater. The No Action alternative, which would maintain the status quo for LANL`s outfalls, was also analyzed. An alternative in which industrial effluent would be treated at the source facilities was considered but dismissed from further analysis because it would not reasonably meet the DOE`s purpose for action, and its potential environmental effects were bounded by the analysis of the Proposed Action and the No Action alternatives.« less

Ecological baseline studies in Los Alamos and Guaje Canyons County of Los Alamos, New Mexico. A two-year study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foxx, T.S.

1995-11-01

During the summers of 1993 and 1994, the Biological Resource Evaluations Team (BRET) of the Environmental Protection Group (ESH-8) conducted baseline studies within two canyon systems, Los Alamos and Guaje Canyons. Biological data was collected within each canyon to provide background and baseline information for Ecological Risk models. Baseline studies included establishment of permanent vegetation plots within each canyon along the elevational gradient. Then, in association with the various vegetation types, surveys were conducted for ground dwelling insects, birds, and small mammals. The stream channels associated with the permanent vegetation plots were characterized and aquatic macroinvertebrates collected within the streammore » monthly throughout a six-month period. The Geographic Position System (GPS) in combination with ARC INFO was used to map the study areas. Considerable data was collected during these surveys and are summarized in individual chapters.« less

Los Alamos Science, Number 25 -- 1997: Celebrating the Neutrino

DOE R&D Accomplishments Database

Cooper, N. G. ed.

1997-01-01

This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solar neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.

Los Alamos Guns Take Aim at Material's Mysteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byers, Mark; Moore, David; Dimarino, Steve

Los Alamos National Laboratory scientists and technicians conduct thousands of experiments a year, delving into the fundamental nature of everything from supernovas to subatomic particles. One set of instruments used to better understand the fundamental nature of various materials are 10 scientific gun systems that fire various projectiles at high-tech targets to create enormous velocities, pressures, and temperatures - and using laser, x-ray, and other diagnostics - explore the very nature of metals and other materials. The hundreds of gun-based experiments conducted every year at the Laboratory require a highly-skilled staff of scientists and technicians, and has given rise tomore » a special organization called the "gun working group" to foster open communications, cooperation, problem-solving, and a healthy safety culture.« less

Smoking patterns among Los Alamos National Laboratory employees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahoney, M.C.; Wilkinson, G.S.

Smoking patterns among 5507 employees at Los Alamos National Laboratory were investigated for those who underwent physical examinations by occupational physicians from 1978 to 1983. More male than female employees smoked, although differences in smoking rates between the sexes were not as large as differences observed for national smoking rates. Employees over 40 were more likely to smoke than younger employees, males consumed more cigarettes than did females, and Anglo employees smoked more cigarettes than did Hispanic employees. Highly educated employees smoked less than did less-educated workers, and staff members exhibited the lowest rates of smoking. Smoking cessation programs formore » Laboratory employees should be directed toward those subpopulations with the highest rates of smoking. 31 refs., 8 figs., 1 tab.« less

Los Alamos Guns Take Aim at Material's Mysteries

ScienceCinema

Byers, Mark; Moore, David; Dimarino, Steve

2018-05-30

Los Alamos National Laboratory scientists and technicians conduct thousands of experiments a year, delving into the fundamental nature of everything from supernovas to subatomic particles. One set of instruments used to better understand the fundamental nature of various materials are 10 scientific gun systems that fire various projectiles at high-tech targets to create enormous velocities, pressures, and temperatures - and using laser, x-ray, and other diagnostics - explore the very nature of metals and other materials. The hundreds of gun-based experiments conducted every year at the Laboratory require a highly-skilled staff of scientists and technicians, and has given rise to a special organization called the "gun working group" to foster open communications, cooperation, problem-solving, and a healthy safety culture.

77 FR 3257 - Transfer of Land Tracts Located at Los Alamos National Laboratory, New Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-23

... DEPARTMENT OF ENERGY Transfer of Land Tracts Located at Los Alamos National Laboratory, New Mexico AGENCY: National Nuclear Security Administration, U.S. Department of Energy. ACTION: Amended Record of Decision. SUMMARY: The U.S. Department of Energy's National Nuclear Security Administration (DOE/NNSA) is...

Toward high throughput optical metamaterial assemblies.

PubMed

Fontana, Jake; Ratna, Banahalli R

2015-11-01

Optical metamaterials have unique engineered optical properties. These properties arise from the careful organization of plasmonic elements. Transitioning these properties from laboratory experiments to functional materials may lead to disruptive technologies for controlling light. A significant issue impeding the realization of optical metamaterial devices is the need for robust and efficient assembly strategies to govern the order of the nanometer-sized elements while enabling macroscopic throughput. This mini-review critically highlights recent approaches and challenges in creating these artificial materials. As the ability to assemble optical metamaterials improves, new unforeseen opportunities may arise for revolutionary optical devices.

Leading Change: A Case Study of Alamo Academies--An Industry-Driven Workforce Partnership Program

ERIC Educational Resources Information Center

Hu, Xiaodan; Bowman, Gene

2016-01-01

In this study, the authors focus on the initiation and development of the Alamo Academies, aiming to illustrate an exemplary industry-driven model that addresses workforce development in local community. After a brief introduction of the context, the authors summarized major factors that contribute to the success of the collaboration model,…

Stormwater Pollution Prevention Plan for the TA-03-38 Metals Fabrication Shop, Los Alamos National Laboratory, Revision 3, January 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgin, Jillian Elizabeth

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector AA-Fabricated Metal Products as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-03-38 Metals Fabrication Shop at Los Alamos National Laboratory. Los Alamos National Laboratorymore » (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-03-38 Metals Fabrication Shop and associated areas. The current permit expires at midnight on June 4, 2020.« less

Stormwater Pollution Prevention Plan for the TA-60-01 Heavy Equipment Shop, Los Alamos National Laboratory, Revision 3, January 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgin, Jillian Elizabeth

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector P-Land Transportation and Warehousing as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-60-01 Heavy Equipment Shop at Los Alamos National Laboratory. Los Alamos Nationalmore » Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-60-01 Heavy Equipment Shop and associated areas. The current permit expires at midnight on June 4, 2020.« less

Environmental Surveillance at Los Alamos during 2007

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Environmental Surveillance at Los Alamos reports are prepared annually by the Los Alamos National Laboratory (the Laboratory) Environmental Directorate, as required by US Department of Energy Order 450.1, General Environmental Protection Program, and US Department of Energy Order 231.1A, Environment, Safety, and Health Reporting. These annual reports summarize environmental data that are used to determine compliance with applicable federal, state, and local environmental laws and regulations, executive orders, and departmental policies. Additional data, beyond the minimum required, are also gathered and reported as part of the Laboratory’s efforts to ensure public safety and to monitor environmental quality at and nearmore » the Laboratory. Chapter 1 provides an overview of the Laboratory’s major environmental programs and explains the risks and the actions taken to reduce risks at the Laboratory from environmental legacies and waste management operations. Chapter 2 reports the Laboratory’s compliance status for 2007. Chapter 3 provides a summary of the maximum radiological dose the public and biota populations could have potentially received from Laboratory operations and discusses chemical exposures. The environmental surveillance and monitoring data are organized by environmental media (Chapter 4, air; Chapters 5 and 6, water and sediments; Chapter 7, soils; and Chapter 8, foodstuffs and biota) in a format to meet the needs of a general and scientific audience. Chapter 9 provides a summary of the status of environmental restoration work around LANL. A glossary and a list of acronyms and abbreviations are in the back of the report. Appendix A explains the standards for environmental contaminants, Appendix B explains the units of measurements used in this report, Appendix C describes the laboratory’s technical areas and their associated programs, and Appendix D provides web links to more information. In printed copies of this report or Executive Summary

The "El Alamo" project (1990-1997): two consecutive hospital-based studies of breast cancer outcomes in Spain.

PubMed

Martín, M; Mahillo, E; Llombart-Cussac, A; Lluch, A; Munarriz, B; Pastor, M; Alba, E; Ruiz, A; Antón, A; Bermejo, B

2006-07-01

The "Alamo" project is a retrospective analysis of 14,854 patients diagnosed of breast cancer between 1990 and 1997 in 50 Spanish hospitals. Alamo I (AI) consisted of 4,532 patients diagnosed with breast cancer between 1990 and 1993. Data were collected in 2000. Alamo II (AII) consisted of 10,322 patients diagnosed between 1994 and 1997. Data were collected in 2003. At presentation, there were (AI vs. AII) 17.6% vs. 24.3% at stage I; 55.5% vs. 53.1% at stage II; 18.7% vs. 15% at stage III; 7.2% vs. 5.9 at stage IV. Median age was 57 (AI) vs. 58 years (AII) and 65.9% vs. 67.2% (AI vs. AII) were post-menopausal. Firstline treatment for disease stages I, II and III was surgery in 91% of patients in both studies. Breast conserving surgery rate increased from 20.2% (AI) to 32.7% (AII). Adjuvant systemic treatments were administered to 87.6% (AI) and 92.8% (AII) of patients. Recurrence rate diminished from 36.6% (AI) to 22.5% (AII) and the 9-year survival rate increased from 63.2% (95% CI: 61.5-64.9) to 70.1% (95% CI: 68.5-71.8). Breast cancer outcomes in Spain have improved from 1990-1993 to 1994-1997, likely because of breast cancer screening program implementation and new therapies.

Measuring the efficiency of control rods in the RBMK critical assembly using a model of RKI-1 reactimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhitarev, V. E., E-mail: vejitarev@yandex.ru; Lebedev, G. V.; Sergevnin, A. Yu.

2016-12-15

The efficiency of control rods of the RBMK critical assembly is measured in a series of experiments. The aim of measurements is to determine the characteristics of the model of an RKI-1 reactimeter. The RKI-1 reactimeter is intended for measuring the efficiency of control rods when, according to conditions of operation, the metrological certification of results of an experiment is required. Complications with the metrological certification of reactimeters arise owing to the fact that usually calculated corrections to the results of measurements are required. When the RKI-1 reactimeter is used, there is no need to introduce calculated corrections; the resultmore » of measurements is given with the indication of substantiated errors. In connection with this, the metrological certification of the results of measurements using the RKI-1 reactimeter is simplified.« less

Erosion and Deposition Monitoring Using High-Density Aerial Lidar and Geomorphic Change Detection Software Analysis at Los Alamos National Laboratory, Los Alamos New Mexico, LA-UR-17-26743

NASA Astrophysics Data System (ADS)

Walker, T.; Kostrubala, T. L.; Muggleton, S. R.; Veenis, S.; Reid, K. D.; White, A. B.

2017-12-01

The Los Alamos National Laboratory storm water program installed sediment transport mitigation structures to reduce the migration of contaminants within the Los Alamos and Pueblo (LA/P) watershed in Los Alamos, NM. The goals of these structures are to minimize storm water runoff and erosion, enhance deposition, and reduce mobility of contaminated sediments. Previous geomorphological monitoring used GPS surveyed cross-sections on a reach scale to interpolate annual geomorphic change in sediment volumes. While monitoring has confirmed the LA/P watershed structures are performing as designed, the cross-section method proved difficult to estimate uncertainty and the coverage area was limited. A new method, using the Geomorphic Change Detection (GCD) plugin for ESRI ArcGIS developed by Wheaton et al. (2010), with high-density aerial lidar data, has been used to provide high confidence uncertainty estimates and greater areal coverage. Following the 2014 monsoon season, airborne lidar data has been collected annually and the resulting DEMs processed using the GCD method. Additionally, a more accurate characterization of low-amplitude geomorphic changes, typical of low-flow/low-rainfall monsoon years, has been documented by applying a spatially variable error to volume change calculations using the GCD based fuzzy inference system (FIS). The FIS method allows for the calculation of uncertainty based on data set quality and density e.g. point cloud density, ground slope, and degree of surface roughness. At the 95% confidence level, propagated uncertainty estimates of the 2015 and 2016 lidar DEM comparisons yielded detectable changes greater than 0.3 m - 0.46 m. Geomorphic processes identified and verified in the field are typified by low-amplitude, within-channel aggradation and incision and out of channel bank collapse that over the course of a monsoon season result in localized and dectetable change. While the resulting reach scale volume change from 2015 - 2016 was often

Alamos: An International Collaboration to Provide a Space Based Environmental Monitoring Solution for the Deep Space Network

NASA Astrophysics Data System (ADS)

Kennedy, S. O.; Dunn, A.; Lecomte, J.; Buchheim, K.; Johansson, E.; Berger, T.

2018-02-01

This abstract proposes the advantages of an externally mounted instrument in support of the human physiology, space biology, and human health and performance key science area. Alamos provides Space-Based Environmental Monitoring capabilities.

Pinon Pine Tree Study, Los Alamos National Laboratory: Source document

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. R. Fresquez; J. D. Huchton; M. A. Mullen

One of the dominant tree species growing within and around Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis) tree. Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food--the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup tot}U, {sup 238}Pu, {sup 239,240}Pu, and {sup 241}Am in soils (0- to 12-in. [31 cm] depth underneath themore » tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) concentrations of radionuclides in PPN collected in 1977 to present data, (3) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (4) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of {sup 3}H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 {micro}Sv). Soil-to-nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.« less

Feral Cattle in the White Rock Canyon Reserve at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hathcock, Charles D.; Hansen, Leslie A.

2014-03-27

At the request of the Los Alamos Field Office (the Field Office), Los Alamos National Security (LANS) biologists placed remote-triggered wildlife cameras in and around the mouth of Ancho Canyon in the White Rock Canyon Reserve (the Reserve) to monitor use by feral cattle. The cameras were placed in October 2012 and retrieved in January 2013. Two cameras were placed upstream in Ancho Canyon away from the Rio Grande along the perennial flows from Ancho Springs, two cameras were placed at the north side of the mouth to Ancho Canyon along the Rio Grande, and two cameras were placed atmore » the south side of the mouth to Ancho Canyon along the Rio Grande. The cameras recorded three different individual feral cows using this area as well as a variety of local native wildlife. This report details our results and issues associated with feral cattle in the Reserve. Feral cattle pose significant risks to human safety, impact cultural and biological resources, and affect the environmental integrity of the Reserve. Regional stakeholders have communicated to the Field Office that they support feral cattle removal.« less

Encoded physics knowledge in checking codes for nuclear cross section libraries at Los Alamos

NASA Astrophysics Data System (ADS)

Parsons, D. Kent

2017-09-01

Checking procedures for processed nuclear data at Los Alamos are described. Both continuous energy and multi-group nuclear data are verified by locally developed checking codes which use basic physics knowledge and common-sense rules. A list of nuclear data problems which have been identified with help of these checking codes is also given.

Summary of ORSphere Critical and Reactor Physics Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Margaret A.; Bess, John D.

In the early 1970s Dr. John T. Mihalczo (team leader), J. J. Lynn, and J. R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950s. The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with the GODIVAmore » I experiments. This critical configuration has been evaluated. Preliminary results were presented at ND2013. Since then, the evaluation was finalized and judged to be an acceptable benchmark experiment for the International Criticality Safety Benchmark Experiment Project (ICSBEP). Additionally, reactor physics measurements were performed to determine surface button worths, central void worth, delayed neutron fraction, prompt neutron decay constant, fission density and neutron importance. These measurements have been evaluated and found to be acceptable experiments and are discussed in full detail in the International Handbook of Evaluated Reactor Physics Benchmark Experiments. The purpose of this paper is summary summarize all the critical and reactor physics measurements evaluations and, when possible, to compare them to GODIVA experiment results.« less

Supplement Analysis for the Site-Wide Environmental Impact Statement for Continued Operation of Los Alamos National Laboratory -- Recovery and Storage of Strontium-90 Fueled Radioisotope Thermal Electric Generators at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

N /A

2004-01-22

This Supplement Analysis (SA) has been prepared to determine if the Site-Wide Environmental Impact Statement for Continued Operations of Los Alamos National Laboratory (SWEIS) (DOE/EIS-0238) adequately addresses the environmental effects of recovery and storage for disposal of six strontium-90 (Sr-90) fueled radioisotope thermal electric generators (RTGs) at the Los Alamos National Laboratory (LANL) Technical Area (TA)-54, Area G, or if the SWEIS needs to be supplemented. DOE's National Nuclear Security Administration (NNSA) proposed to recover and store six Sr-90 RTGs from the commercial sector as part of its Offsite-Source Recovery Project (OSRP). The OSRP focuses on the proactive recovery andmore » storage of unwanted radioactive sealed sources exceeding the US Nuclear Regulatory Commission (NRC) limits for Class C low-level waste (also known as Greater than Class C waste, or GTCC). In response to the events of September 11, 2001, NRC conducted a risk-based evaluation of potential vulnerabilities to terrorist threats involving NRC-licensed nuclear facilities and materials. NRC's evaluation concluded that possession of unwanted radioactive sealed sources with no disposal outlet presents a potential vulnerability (NRC 2002). In a November 25, 2003 letter to the manager of the NNSA's Los Alamos Site Office, the NRC Office of Nuclear Security and Incident Response identified recovery of several Sr-90 RTGs as the highest priority and requested that DOE take whatever actions necessary to recovery these sources as soon as possible. This SA specifically compares key impact assessment parameters of this proposal to the offsite source recovery program evaluated in the SWEIS and a subsequent SA that evaluated a change to the approach of a portion of the recovery program. It also provides an explanation of any differences between the Proposed Action and activities described in the previous SWEIS and SA analyses.« less

Post-Cold War Science and Technology at Los Alamos

NASA Astrophysics Data System (ADS)

Browne, John C.

2002-04-01

Los Alamos National Laboratory serves the nation through the development and application of leading-edge science and technology in support of national security. Our mission supports national security by: ensuring the safety, security, and reliability of the U.S. nuclear stockpile; reducing the threat of weapons of mass destruction in support of counter terrorism and homeland defense; and solving national energy, environment, infrastructure, and health security problems. We require crosscutting fundamental and advanced science and technology research to accomplish our mission. The Stockpile Stewardship Program develops and applies, advanced experimental science, computational simulation, and technology to ensure the safety and reliability of U.S. nuclear weapons in the absence of nuclear testing. This effort in itself is a grand challenge. However, the terrorist attack of September 11, 2001, reminded us of the importance of robust and vibrant research and development capabilities to meet new and evolving threats to our national security. Today through rapid prototyping we are applying new, innovative, science and technology for homeland defense, to address the threats of nuclear, chemical, and biological weapons globally. Synergistically, with the capabilities that we require for our core mission, we contribute in many other areas of scientific endeavor. For example, our Laboratory has been part of the NASA effort on mapping water on the moon and NSF/DOE projects studying high-energy astrophysical phenomena, understanding fundamental scaling phenomena of life, exploring high-temperature superconductors, investigating quantum information systems, applying neutrons to condensed-matter and nuclear physics research, developing large-scale modeling and simulations to understand complex phenomena, and exploring nanoscience that bridges the atomic to macroscopic scales. In this presentation, I will highlight some of these post-cold war science and technology advances

2016 Los Alamos National Laboratory Hazardous Waste Minimization Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salzman, Sonja L.; English, Charles Joe

Waste minimization and pollution prevention are goals within the operating procedures of Los Alamos National Security, LLC (LANS). The US Department of Energy (DOE), inclusive of the National Nuclear Security Administration (NNSA) and the Office of Environmental Management, and LANS are required to submit an annual hazardous waste minimization report to the New Mexico Environment Department (NMED) in accordance with the Los Alamos National Laboratory (LANL or the Laboratory) Hazardous Waste Facility Permit. The report was prepared pursuant to the requirements of Section 2.9 of the LANL Hazardous Waste Facility Permit. This report describes the hazardous waste minimization program, whichmore » is a component of the overall Pollution Prevention (P2) Program, administered by the Environmental Stewardship Group (EPC-ES). This report also supports the waste minimization and P2 goals of the Associate Directorate of Environmental Management (ADEM) organizations that are responsible for implementing remediation activities and describes its programs to incorporate waste reduction practices into remediation activities and procedures. This report includes data for all waste shipped offsite from LANL during fiscal year (FY) 2016 (October 1, 2015 – September 30, 2016). LANS was active during FY2016 in waste minimization and P2 efforts. Multiple projects were funded that specifically related to reduction of hazardous waste. In FY2016, there was no hazardous, mixed-transuranic (MTRU), or mixed low-level (MLLW) remediation waste shipped offsite from the Laboratory. More non-remediation hazardous waste and MLLW was shipped offsite from the Laboratory in FY2016 compared to FY2015. Non-remediation MTRU waste was not shipped offsite during FY2016. These accomplishments and analysis of the waste streams are discussed in much more detail within this report.« less

A review of the Los Alamos effort in the development of nuclear rocket propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durham, F.P.; Kirk, W.L.; Bohl, R.J.

1991-01-01

This paper reviews the achievements of the Los Alamos nuclear rocket propulsion program and describes some specific reactor design and testing problems encountered during the development program along with the progress made in solving these problems. The relevance of these problems to a renewed nuclear thermal rocket development program for the Space Exploration Initiative (SEI) is discussed. 11 figs.

Los Alamos Neutron Science Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kippen, Karen Elizabeth

For more than 30 years the Los Alamos Neutron Science Center (LANSCE) has provided the scientific underpinnings in nuclear physics and material science needed to ensure the safety and surety of the nuclear stockpile into the future. In addition to national security research, the LANSCE User Facility has a vibrant research program in fundamental science, providing the scientific community with intense sources of neutrons and protons to perform experiments supporting civilian research and the production of medical and research isotopes. Five major experimental facilities operate simultaneously. These facilities contribute to the stockpile stewardship program, produce radionuclides for medical testing, andmore » provide a venue for industrial users to irradiate and test electronics. In addition, they perform fundamental research in nuclear physics, nuclear astrophysics, materials science, and many other areas. The LANSCE User Program plays a key role in training the next generation of top scientists and in attracting the best graduate students, postdoctoral researchers, and early-career scientists. The U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) —the principal sponsor of LANSCE—works with the Office of Science and the Office of Nuclear Energy, which have synergistic long-term needs for the linear accelerator and the neutron science that is the heart of LANSCE.« less

Los Alamos Science, Number 25 -- 1997: Celebrating the neutrino

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, N.G.

1997-12-31

This issue is devoted to the neutrino and its remaining mysteries. It is divided into the following areas: (1) The Reines-Cowan experiment -- detecting the poltergeist; (2) The oscillating neutrino -- an introduction to neutrino masses and mixing; (3) A brief history of neutrino experiments at LAMPF; (4) A thousand eyes -- the story of LSND (Los Alamos neutrino oscillation experiment); (5) The evidence for oscillations; (6) The nature of neutrinos in muon decay and physics beyond the Standard Model; (7) Exorcising ghosts -- in pursuit of the missing solar neutrinos; (8) MSW -- a possible solution to the solarmore » neutrino problem; (8) Neutrinos and supernovae; and (9) Dark matter and massive neutrinos.« less

Research to Assembly Scheme for Satellite Deck Based on Robot Flexibility Control Principle

NASA Astrophysics Data System (ADS)

Guo, Tao; Hu, Ruiqin; Xiao, Zhengyi; Zhao, Jingjing; Fang, Zhikai

2018-03-01

Deck assembly is critical quality control point in final satellite assembly process, and cable extrusion and structure collision problems in assembly process will affect development quality and progress of satellite directly. Aimed at problems existing in deck assembly process, assembly project scheme for satellite deck based on robot flexibility control principle is proposed in this paper. Scheme is introduced firstly; secondly, key technologies on end force perception and flexible docking control in the scheme are studied; then, implementation process of assembly scheme for satellite deck is described in detail; finally, actual application case of assembly scheme is given. Result shows that compared with traditional assembly scheme, assembly scheme for satellite deck based on robot flexibility control principle has obvious advantages in work efficiency, reliability and universality aspects etc.

Los Alamos National Laboratory Meteorology Monitoring Program: 2016 Data Completeness/ Quality Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruggeman, David Alan

This report summarizes data completeness by tower and by instrument for 2016 and compares that data with the Los Alamos National Laboratory (LANL) and American National Standards Institute (ANSI) 2015 standards. This report is designed to make data users aware of data completeness and any data quality issues. LANL meteorology monitoring goals include 95% completeness for all measurements. The ANSI 2015 standard requires 90% completeness for all measurements. This report documents instrument/tower issues as they impact data completeness.

A Manual for the Prediction of Blast and Fragment Loadings on Structures

DTIC Science & Technology

1981-08-15

ives , assembles exp los ives components i n t o assemblies , does more i n s p e c t i o n s , and f i n a l l y packages and s h i p s t h...4100, Los Alamos S c i e n t i f i c Laboratory, Un ive r s i ty of C a l i f o r n i a , Los Alamos , New Mexico, February 1970. 4.29 " I n t e...Massachusetts I n s t i t u t e of Technology, 1976. B- 7 Bdzi l , J. B. and Davis, W. C., "Time-Dependent Detonat ions," J.A-5926-MS, Los Alamos S c i

Saving Water at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erickson, Andy

Los Alamos National Laboratory decreased its water usage by 26 percent in 2014, with about one-third of the reduction attributable to using reclaimed water to cool a supercomputing center. The Laboratory's goal during 2014 was to use only re-purposed water to support the mission at the Strategic Computing Complex. Using reclaimed water from the Sanitary Effluent Reclamation Facility, or SERF, substantially decreased water usage and supported the overall mission. SERF collects industrial wastewater and treats it for reuse. The reclamation facility contributed more than 27 million gallons of re-purposed water to the Laboratory's computing center, a secured supercomputing facility thatmore » supports the Laboratory’s national security mission and is one of the institution’s larger water users. In addition to the strategic water reuse program at SERF, the Laboratory reduced water use in 2014 by focusing conservation efforts on areas that use the most water, upgrading to water-conserving fixtures, and repairing leaks identified in a biennial survey.« less

Saving Water at Los Alamos National Laboratory

ScienceCinema

Erickson, Andy

2018-01-16

Los Alamos National Laboratory decreased its water usage by 26 percent in 2014, with about one-third of the reduction attributable to using reclaimed water to cool a supercomputing center. The Laboratory's goal during 2014 was to use only re-purposed water to support the mission at the Strategic Computing Complex. Using reclaimed water from the Sanitary Effluent Reclamation Facility, or SERF, substantially decreased water usage and supported the overall mission. SERF collects industrial wastewater and treats it for reuse. The reclamation facility contributed more than 27 million gallons of re-purposed water to the Laboratory's computing center, a secured supercomputing facility that supports the Laboratory’s national security mission and is one of the institution’s larger water users. In addition to the strategic water reuse program at SERF, the Laboratory reduced water use in 2014 by focusing conservation efforts on areas that use the most water, upgrading to water-conserving fixtures, and repairing leaks identified in a biennial survey.

Crystal structure of an HIV assembly and maturation switch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wagner, Jonathan M.; Zadrozny, Kaneil K.; Chrustowicz, Jakub

Virus assembly and maturation proceed through the programmed operation of molecular switches, which trigger both local and global structural rearrangements to produce infectious particles. HIV-1 contains an assembly and maturation switch that spans the C-terminal domain (CTD) of the capsid (CA) region and the first spacer peptide (SP1) of the precursor structural protein, Gag. The crystal structure of the CTD-SP1 Gag fragment is a goblet-shaped hexamer in which the cup comprises the CTD and an ensuing type II β-turn, and the stem comprises a 6-helix bundle. The β-turn is critical for immature virus assembly and the 6-helix bundle regulates proteolysismore » during maturation. This bipartite character explains why the SP1 spacer is a critical element of HIV-1 Gag but is not a universal property of retroviruses. Our results also indicate that HIV-1 maturation inhibitors suppress unfolding of the CA-SP1 junction and thereby delay access of the viral protease to its substrate.« less

IMPACTS OF DRILLING ADDITIVES ON DATA OBTAINED FROM HYDROGEOLOGIC CHARACTERIZATION WELLS AT LOS ALAMOS NATIONAL LABORATORY

EPA Science Inventory

Personnel at the EPA Ground Water and Ecosystems Restoration Division (GWERD) were requested by EPA Region 6 to evaluate the impacts of well drilling practices at the Los Alamos National Laboratory (LANL). The focus of this review involved analysis of the impacts of bentonite- a...

Self-assembly behaviours of peptide-drug conjugates: influence of multiple factors on aggregate morphology and potential self-assembly mechanism

NASA Astrophysics Data System (ADS)

Fan, Qin; Ji, Yujie; Wang, Jingjing; Wu, Li; Li, Weidong; Chen, Rui; Chen, Zhipeng

2018-04-01

Peptide-drug conjugates (PDCs) as self-assembly prodrugs have the unique and specific features to build one-component nanomedicines. Supramolecular structure based on PDCs could form various morphologies ranging from nanotube, nanofibre, nanobelt to hydrogel. However, the assembly process of PDCs is too complex to predict or control. Herein, we investigated the effects of extrinsic factors on assembly morphology and the possible formation of nanostructures based on PDCs. To this end, we designed a PDC consisting of hydrophobic drug (S)-ketoprofen (Ket) and valine-glutamic acid dimeric repeats peptide (L-VEVE) to study their assembly behaviour. Our results showed that the critical assembly concentration of Ket-L-VEVE was 0.32 mM in water to form various nanostructures which experienced from micelle, nanorod, nanofibre to nanoribbon. The morphology was influenced by multiple factors including molecular design, assembly time, pH and hydrogen bond inhibitor. On the basis of experimental results, we speculated the possible assembly mechanism of Ket-L-VEVE. The π-π stacking interaction between Ket molecules could serve as an anchor, and hydrogen bonded-induced β-sheets and hydrophilic/hydrophobic balance between L-VEVE peptide play structure-directing role in forming filament-like or nanoribbon morphology. This work provides a new sight to rationally design and precisely control the nanostructure of PDCs based on aromatic fragment.

Self-assembly behaviours of peptide-drug conjugates: influence of multiple factors on aggregate morphology and potential self-assembly mechanism.

PubMed

Fan, Qin; Ji, Yujie; Wang, Jingjing; Wu, Li; Li, Weidong; Chen, Rui; Chen, Zhipeng

2018-04-01

Peptide-drug conjugates (PDCs) as self-assembly prodrugs have the unique and specific features to build one-component nanomedicines. Supramolecular structure based on PDCs could form various morphologies ranging from nanotube, nanofibre, nanobelt to hydrogel. However, the assembly process of PDCs is too complex to predict or control. Herein, we investigated the effects of extrinsic factors on assembly morphology and the possible formation of nanostructures based on PDCs. To this end, we designed a PDC consisting of hydrophobic drug ( S )-ketoprofen (Ket) and valine-glutamic acid dimeric repeats peptide (L-VEVE) to study their assembly behaviour. Our results showed that the critical assembly concentration of Ket-L-VEVE was 0.32 mM in water to form various nanostructures which experienced from micelle, nanorod, nanofibre to nanoribbon. The morphology was influenced by multiple factors including molecular design, assembly time, pH and hydrogen bond inhibitor. On the basis of experimental results, we speculated the possible assembly mechanism of Ket-L-VEVE. The π-π stacking interaction between Ket molecules could serve as an anchor, and hydrogen bonded-induced β-sheets and hydrophilic/hydrophobic balance between L-VEVE peptide play structure-directing role in forming filament-like or nanoribbon morphology. This work provides a new sight to rationally design and precisely control the nanostructure of PDCs based on aromatic fragment.

Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yuecheng; Li, Bo; Li, Songsong

Advances in supramolecular assembly have enabled the design and synthesis of functional materials with well-defined structures across multiple length scales. Biopolymer-synthetic hybrid materials can assemble into supramolecular structures with a broad range of structural and functional diversity through precisely controlled noncovalent interactions between subunits. Despite recent progress, there is a need to understand the mechanisms underlying the assembly of biohybrid/synthetic molecular building blocks, which ultimately control the emergent properties of hierarchical assemblies. Here in this work, we study the concentration-driven self-assembly and gelation of π-conjugated synthetic oligopeptides containing different π-conjugated cores (quaterthiophene and perylene diimide) using a combination of particlemore » tracking microrheology, confocal fluorescence microscopy, optical spectroscopy, and electron microscopy. Our results show that π-conjugated oligopeptides self-assemble into β-sheet-rich fiber-like structures at neutral pH, even in the absence of electrostatic screening of charged residues. A critical fiber formation concentration c fiber and a critical gel concentration c gel are determined for fiber-forming π-conjugated oligopeptides, and the linear viscoelastic moduli (storage modulus G' and loss modulus G") are determined across a wide range of peptide concentrations. These results suggest that the underlying chemical structure of the synthetic π-conjugated cores greatly influences the self-assembly process, such that oligopeptides appended to π-conjugated cores with greater torsional flexibility tend to form more robust fibers upon increasing peptide concentration compared to oligopeptides with sterically constrained cores. Overall, our work focuses on the molecular assembly of π-conjugated oligopeptides driven by concentration, which is controlled by a combination of enthalpic and entropic interactions between oligopeptide subunits.« less

Concentration-Driven Assembly and Sol–Gel Transition of π-Conjugated Oligopeptides

DOE PAGES

Zhou, Yuecheng; Li, Bo; Li, Songsong; ...

2017-08-17

Advances in supramolecular assembly have enabled the design and synthesis of functional materials with well-defined structures across multiple length scales. Biopolymer-synthetic hybrid materials can assemble into supramolecular structures with a broad range of structural and functional diversity through precisely controlled noncovalent interactions between subunits. Despite recent progress, there is a need to understand the mechanisms underlying the assembly of biohybrid/synthetic molecular building blocks, which ultimately control the emergent properties of hierarchical assemblies. Here in this work, we study the concentration-driven self-assembly and gelation of π-conjugated synthetic oligopeptides containing different π-conjugated cores (quaterthiophene and perylene diimide) using a combination of particlemore » tracking microrheology, confocal fluorescence microscopy, optical spectroscopy, and electron microscopy. Our results show that π-conjugated oligopeptides self-assemble into β-sheet-rich fiber-like structures at neutral pH, even in the absence of electrostatic screening of charged residues. A critical fiber formation concentration c fiber and a critical gel concentration c gel are determined for fiber-forming π-conjugated oligopeptides, and the linear viscoelastic moduli (storage modulus G' and loss modulus G") are determined across a wide range of peptide concentrations. These results suggest that the underlying chemical structure of the synthetic π-conjugated cores greatly influences the self-assembly process, such that oligopeptides appended to π-conjugated cores with greater torsional flexibility tend to form more robust fibers upon increasing peptide concentration compared to oligopeptides with sterically constrained cores. Overall, our work focuses on the molecular assembly of π-conjugated oligopeptides driven by concentration, which is controlled by a combination of enthalpic and entropic interactions between oligopeptide subunits.« less

Neutron and gamma-ray dose measurements at various distances from the Little Boy replica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huntzinger, C.J.; Hankins, D.E.

We measured neutron and gamma-ray dose rates at various distances from the Little Boy-Comet Critical Assembly at Los Alamos National Laboratory (LANL) in April of 1983. The Little Boy-Comet Assembly is a replica of the atomic weapon detonated over Hiroshima, designed to be operated at various steady-state power levels. The selected distances for measurement ranged from 107 m to 567 m. Gamma-ray measurements were made with a Reuter-Stokes environmental ionization chamber which has a sensitivity of 1.0 ..mu..R/hour. Neutron measurements were made with a pulsed-source remmeter which has a sensitivity of 0.1 ..mu..rem/hour, designed and built at Lawrence Livermore Nationalmore » Laboratory (LLNL). 12 references, 7 figures, 6 tables.« less

A Tracer Test at the Los Alamos Canyon Weir

NASA Astrophysics Data System (ADS)

Levitt, D. G.; Stone, W. J.; Newell, D. L.; Wykoff, D. S.

2002-12-01

A low-head weir was constructed in the Los Alamos Canyon to reduce the transport of contaminant-bearing sediment caused by fire-enhanced runoff off Los Alamos National Laboratory (LANL) property towards the Rio Grande following the May 2000 Cerro Grande fire at Los Alamos, New Mexico. Fractured basalt was exposed in the channel by grading during construction of the weir, and water temporarily ponds behind the weir following periods of runoff. In order to monitor any downward transport of contaminants into fractured basalt, and potentially downward to the regional ground water, three boreholes (one vertical, one at 43 degrees, and one at 34 degrees from horizontal) were installed for environmental monitoring. The boreholes penetrate to depths ranging from approximately 9 to 82 m below the weir floor. The two angled boreholes are fitted with flexible FLUTe liners with resistance sensors to measure relative moisture content and absorbent sampling pads for contaminant and environmental tracer sampling within the vadose zone. The two angled boreholes are also monitored for relative changes in moisture content by neutron logging. The vertical borehole penetrates three perched water zones and is equipped with four screens and sampling ports. In April 2002, a tracer test was initiated with the application of a 0.2 M (16,000 ppm) solution of potassium bromide (KBr) onto the weir floor. The tracer experiment was intended to provide data on travel times through the complex hydrogeologic media of fractured basalt. A precipitation and runoff event in June 2002 resulted in approximately 0.61 m of standing water behind the weir. If the KBr and flood waters were well mixed, the concentration of KBr in the flood waters was approximately 24 ppm. Bromide was detected in the absorbent membrane in the 43 degree hole at concentrations up to 2 ppm. Resistance sensors in the 43 degree borehole detected moisture increases within 3 days at a depth of 27 m, indicating an average wetting

Pesticide concentrations in water and in suspended and bottom sediments in the New and Alamo rivers, Salton Sea Watershed, California, April 2003

USGS Publications Warehouse

LeBlanc, Lawrence A.; Orlando, James L.; Kuivila, Kathryn

2004-01-01

This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use pesticides associated with water and sediment into the New and Alamo Rivers. Five sites along the New River and seven sites along the Alamo River, downstream of major agricultural drains, were selected and covered the lengths of the rivers from the international boundary to approximately 1.5 km from the river mouths. Sampling from bridges occurred at seven of the twelve sites. At these sites, streamflow measurements were taken. These same sites were also characterized for cross-stream homogeneity by measuring dissolved oxygen, pH, specific conductance, temperature, and suspended solids concentration at several vertical (depths) and horizontal (cross-stream) points across the river. Large volume water samples (200?300 L) were collected for isolation of suspended sediments by flow-through centrifugation. Water from the outflow of the flow-through centrifuge was sampled for the determination of aqueous pesticide concentrations. In addition, bottom sediments were sampled at each site. Current-use pesticides and legacy organochlorine compounds (p,p'-DDT, p,p'-DDE and p,p'-DDD) were extracted from sediments and measured via gas chromatography/mass spectrometry (GC/MS). Organic carbon and percentage of fines were also determined for suspended and bottom sediments. Cross-stream transects of dissolved constituents and suspended sediments showed that the rivers were fairly homogeneous at the sites sampled. Streamflow was higher at the outlet sites, with the Alamo River having higher flow (1,240 cfs) than the New River (798 cfs). Twelve current-use pesticides, one legacy organochlorine compound (p

Los Alamos Discovers Super Efficient Solar Using Perovskite Crystals

ScienceCinema

Mohite, Aditya; Nie, Wanyi

2018-05-11

State-of-the-art photovoltaics using high-purity, large-area, wafer-scale single-crystalline semiconductors grown by sophisticated, high temperature crystal-growth processes offer promising routes for developing low-cost, solar-based clean global energy solutions for the future. Solar cells composed of the recently discovered material organic-inorganic perovskites offer the efficiency of silicon, yet suffer from a variety of deficiencies limiting the commercial viability of perovskite photovoltaic technology. In research to appear in Science, Los Alamos National Laboratory researchers reveal a new solution-based hot-casting technique that eliminates these limitations, one that allows for the growth of high-quality, large-area, millimeter-scale perovskite crystals and demonstrates that highly efficient and reproducible solar cells with reduced trap assisted recombination can be realized.

75 FR 24957 - Decision to Evaluate a Petition to Designate a Class of Employees From the Los Alamos National...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... Laboratory. Location: Los Alamos, New Mexico. Job Titles and/or Job Duties: All employees of the Department.... Hinnefeld, Interim Director, Division of Compensation Analysis and Support, National Institute for...

Modeling the assembly order of multimeric heteroprotein complexes

PubMed Central

Esquivel-Rodriguez, Juan; Terashi, Genki; Christoffer, Charles; Shin, Woong-Hee

2018-01-01

Protein-protein interactions are the cornerstone of numerous biological processes. Although an increasing number of protein complex structures have been determined using experimental methods, relatively fewer studies have been performed to determine the assembly order of complexes. In addition to the insights into the molecular mechanisms of biological function provided by the structure of a complex, knowing the assembly order is important for understanding the process of complex formation. Assembly order is also practically useful for constructing subcomplexes as a step toward solving the entire complex experimentally, designing artificial protein complexes, and developing drugs that interrupt a critical step in the complex assembly. There are several experimental methods for determining the assembly order of complexes; however, these techniques are resource-intensive. Here, we present a computational method that predicts the assembly order of protein complexes by building the complex structure. The method, named Path-LzerD, uses a multimeric protein docking algorithm that assembles a protein complex structure from individual subunit structures and predicts assembly order by observing the simulated assembly process of the complex. Benchmarked on a dataset of complexes with experimental evidence of assembly order, Path-LZerD was successful in predicting the assembly pathway for the majority of the cases. Moreover, when compared with a simple approach that infers the assembly path from the buried surface area of subunits in the native complex, Path-LZerD has the strong advantage that it can be used for cases where the complex structure is not known. The path prediction accuracy decreased when starting from unbound monomers, particularly for larger complexes of five or more subunits, for which only a part of the assembly path was correctly identified. As the first method of its kind, Path-LZerD opens a new area of computational protein structure modeling and will be

Modeling the assembly order of multimeric heteroprotein complexes.

PubMed

Peterson, Lenna X; Togawa, Yoichiro; Esquivel-Rodriguez, Juan; Terashi, Genki; Christoffer, Charles; Roy, Amitava; Shin, Woong-Hee; Kihara, Daisuke

2018-01-01

Protein-protein interactions are the cornerstone of numerous biological processes. Although an increasing number of protein complex structures have been determined using experimental methods, relatively fewer studies have been performed to determine the assembly order of complexes. In addition to the insights into the molecular mechanisms of biological function provided by the structure of a complex, knowing the assembly order is important for understanding the process of complex formation. Assembly order is also practically useful for constructing subcomplexes as a step toward solving the entire complex experimentally, designing artificial protein complexes, and developing drugs that interrupt a critical step in the complex assembly. There are several experimental methods for determining the assembly order of complexes; however, these techniques are resource-intensive. Here, we present a computational method that predicts the assembly order of protein complexes by building the complex structure. The method, named Path-LzerD, uses a multimeric protein docking algorithm that assembles a protein complex structure from individual subunit structures and predicts assembly order by observing the simulated assembly process of the complex. Benchmarked on a dataset of complexes with experimental evidence of assembly order, Path-LZerD was successful in predicting the assembly pathway for the majority of the cases. Moreover, when compared with a simple approach that infers the assembly path from the buried surface area of subunits in the native complex, Path-LZerD has the strong advantage that it can be used for cases where the complex structure is not known. The path prediction accuracy decreased when starting from unbound monomers, particularly for larger complexes of five or more subunits, for which only a part of the assembly path was correctly identified. As the first method of its kind, Path-LZerD opens a new area of computational protein structure modeling and will be

2009 Community College Futures Assembly Focus: Leading Change--Leading in an Uncertain Environment

ERIC Educational Resources Information Center

Campbell, Dale F.; Morris, Phillip A.

2009-01-01

The Community College Futures Assembly has served as a national, independent policy thinktank since 1995. Its purpose is to articulate the critical issues facing American community colleges and recognize innovative programs. Convening annually in January in Orlando, Florida, the Assembly offers a learning environment where tough questions are…

Los Alamos Laser Eye Investigation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odom, C. R.

2005-01-01

A student working in a laser laboratory at Los Alamos National Laboratory sustained a serious retinal injury to her left eye when she attempted to view suspended particles in a partially evacuated target chamber. The principle investigator was using the white light from the flash lamp of a Class 4 Nd:YAG laser to illuminate the particles. Since the Q-switch was thought to be disabled at the time of the accident, the principal investigator assumed it would be safe to view the particles without wearing laser eye protection. The Laboratory Director appointed a team to investigate the accident and to reportmore » back to him the events and conditions leading up to the accident, equipment malfunctions, safety management causal factors, supervisory and management action/inaction, adequacy of institutional processes and procedures, emergency and notification response, effectiveness of corrective actions and lessons learned from previous similar events, and recommendations for human and institutional safety improvements. The team interviewed personnel, reviewed documents, and characterized systems and conditions in the laser laboratory during an intense six week investigation. The team determined that the direct and primary failures leading to this accident were, respectively, the principle investigator's unsafe work practices and the institution's inadequate monitoring of worker performance. This paper describes the details of the investigation, the human and institutional failures, and the recommendations for improving the laser safety program.« less

Assembly: a resource for assembled genomes at NCBI

PubMed Central

Kitts, Paul A.; Church, Deanna M.; Thibaud-Nissen, Françoise; Choi, Jinna; Hem, Vichet; Sapojnikov, Victor; Smith, Robert G.; Tatusova, Tatiana; Xiang, Charlie; Zherikov, Andrey; DiCuccio, Michael; Murphy, Terence D.; Pruitt, Kim D.; Kimchi, Avi

2016-01-01

The NCBI Assembly database (www.ncbi.nlm.nih.gov/assembly/) provides stable accessioning and data tracking for genome assembly data. The model underlying the database can accommodate a range of assembly structures, including sets of unordered contig or scaffold sequences, bacterial genomes consisting of a single complete chromosome, or complex structures such as a human genome with modeled allelic variation. The database provides an assembly accession and version to unambiguously identify the set of sequences that make up a particular version of an assembly, and tracks changes to updated genome assemblies. The Assembly database reports metadata such as assembly names, simple statistical reports of the assembly (number of contigs and scaffolds, contiguity metrics such as contig N50, total sequence length and total gap length) as well as the assembly update history. The Assembly database also tracks the relationship between an assembly submitted to the International Nucleotide Sequence Database Consortium (INSDC) and the assembly represented in the NCBI RefSeq project. Users can find assemblies of interest by querying the Assembly Resource directly or by browsing available assemblies for a particular organism. Links in the Assembly Resource allow users to easily download sequence and annotations for current versions of genome assemblies from the NCBI genomes FTP site. PMID:26578580

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, Margaret A.

In the early 1970s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an effort to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950s. The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with themore » GODIVA I experiments. Additionally, various material reactivity worths, the surface material worth coefficient, the delayed neutron fraction, the prompt neutron decay constant, relative fission density, and relative neutron importance were all measured. The critical assembly, material reactivity worths, the surface material worth coefficient, and the delayed neutron fraction were all evaluated as benchmark experiment measurements. The reactor physics measurements are the focus of this paper; although for clarity the critical assembly benchmark specifications are briefly discussed.« less

Reactor Physics Measurements and Benchmark Specifications for Oak Ridge Highly Enriched Uranium Sphere (ORSphere)

DOE PAGES

Marshall, Margaret A.

2014-11-04

In the early 1970s Dr. John T. Mihalczo (team leader), J.J. Lynn, and J.R. Taylor performed experiments at the Oak Ridge Critical Experiments Facility (ORCEF) with highly enriched uranium (HEU) metal (called Oak Ridge Alloy or ORALLOY) in an effort to recreate GODIVA I results with greater accuracy than those performed at Los Alamos National Laboratory in the 1950s. The purpose of the Oak Ridge ORALLOY Sphere (ORSphere) experiments was to estimate the unreflected and unmoderated critical mass of an idealized sphere of uranium metal corrected to a density, purity, and enrichment such that it could be compared with themore » GODIVA I experiments. Additionally, various material reactivity worths, the surface material worth coefficient, the delayed neutron fraction, the prompt neutron decay constant, relative fission density, and relative neutron importance were all measured. The critical assembly, material reactivity worths, the surface material worth coefficient, and the delayed neutron fraction were all evaluated as benchmark experiment measurements. The reactor physics measurements are the focus of this paper; although for clarity the critical assembly benchmark specifications are briefly discussed.« less

Structural Geology of the Northwestern Portion of Los Alamos National Laboratory, Rio Grande Rift, New Mexico: Implications for Seismic Surface Rupture Potential from TA-3 to TA-55

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamie N. Gardner: Alexis Lavine; Giday WoldeGabriel; Donathon Krier

1999-03-01

Los Alamos National Laboratory lies at the western boundary of the Rio Grande rift, a major tectonic feature of the North American Continent. Three major faults locally constitute the modem rift boundary, and each of these is potentially seismogenic. In this study we have gathered structural geologic data for the northwestern portion of Los Alamos National Laboratory through high-precision geologic mapping, conventional geologic mapping, stratigraphic studies, drilling, petrologic studies, and stereographic aerial photograph analyses. Our study area encompasses TA-55 and TA-3, where potential for seismic surface rupture is of interest, and is bounded on the north and south by themore » townsite of Los Alamos and Twomile Canyon, respectively. The study area includes parts of two of the potentially active rift boundary faults--the Pajarito and Rendija Canyon faults-that form a large graben that we name the Diamond Drive graben. The graben embraces the western part of the townsite of Los Alamos, and its southern end is in the TA-3 area where it is defined by east-southeast-trending cross faults. The cross faults are small, but they accommodate interactions between the two major fault zones and gentle tilting of structural blocks to the north into the graben. North of Los Alamos townsite, the Rendija Canyon fault is a large normal fault with about 120 feet of down-to-the-west displacement over the last 1.22 million years. South from Los Alamos townsite, the Rendija Canyon fault splays to the southwest into a broad zone of deformation. The zone of deformation is about 2,000 feet wide where it crosses Los Alamos Canyon and cuts through the Los Alamos County Landfill. Farther southwest, the fault zone is about 3,000 feet wide at the southeastern corner of TA-3 in upper Mortandad Canyon and about 5,000 feet wide in Twomile Canyon. Net down-to-the-west displacement across the entire fault zone over the last 1.22 million years decreases to the south as the fault zone

Hepatitis E virus capsid protein assembles in 4M urea in the presence of salts.

PubMed

Yang, Chunyan; Pan, Huirong; Wei, Minxi; Zhang, Xiao; Wang, Nan; Gu, Ying; Du, Hailian; Zhang, Jun; Li, Shaowei; Xia, Ningshao

2013-03-01

The hepatitis E virus (HEV) capsid protein has been demonstrated to be able to assemble into particles in vitro. However, this process and the mechanism of protein-protein interactions during particle assembly remain unclear. In this study, we investigated the assembly mechanism of HEV structural protein subunits, the capsid protein p239 (aa368-606), using analytical ultracentrifugation. It was the first to observe that the p239 can form particles in 4M urea as a result of supplementation with salt, including ammonium sulfate [(NH₄)₂SO₄], sodium sulfate (Na₂SO₄), sodium chloride (NaCl), and ammonium chloride (NH₄Cl). Interestingly, it is the ionic strength that determines the efficiency of promoting particle assembly. The assembly rate was affected by temperature and salt concentration. When (NH₄)₂SO₄ was used, assembling intermediates of p239 with sedimentation coefficient values of approximately 5 S, which were mostly dodecamers, were identified for the first time. A highly conserved 28-aa region (aa368-395) of p239 was found to be critical for particle assembly, and the hydrophobic residues Leu³⁷², Leu³⁷⁵, and Leu³⁹⁵ of p239 was found to be critical for particle assembly, which was revealed by site-directed mutagenesis. This study provides new insights into the assembly mechanism of native HEV, and contributes a valuable basis for further investigations of protein assembly by hydrophobic interactions under denaturing conditions. Copyright © 2012 The Protein Society.

JEFF-3.1, ENDF/B-VII and JENDL-3.3 Critical Assemblies Benchmarking With the Monte Carlo Code TRIPOLI

NASA Astrophysics Data System (ADS)

Sublet, Jean-Christophe

2008-02-01

ENDF/B-VII.0, the first release of the ENDF/B-VII nuclear data library, was formally released in December 2006. Prior to this event the European JEFF-3.1 nuclear data library was distributed in April 2005, while the Japanese JENDL-3.3 library has been available since 2002. The recent releases of these neutron transport libraries and special purpose files, the updates of the processing tools and the significant progress in computer power and potency, allow today far better leaner Monte Carlo code and pointwise library integration leading to enhanced benchmarking studies. A TRIPOLI-4.4 critical assembly suite has been set up as a collection of 86 benchmarks taken principally from the International Handbook of Evaluated Criticality Benchmarks Experiments (2006 Edition). It contains cases for a variety of U and Pu fuels and systems, ranging from fast to deep thermal solutions and assemblies. It covers cases with a variety of moderators, reflectors, absorbers, spectra and geometries. The results presented show that while the most recent library ENDF/B-VII.0, which benefited from the timely development of JENDL-3.3 and JEFF-3.1, produces better overall results, it suggest clearly also that improvements are still needed. This is true in particular in Light Water Reactor applications for thermal and epithermal plutonium data for all libraries and fast uranium data for JEFF-3.1 and JENDL-3.3. It is also true to state that other domains, in which Monte Carlo code are been used, such as astrophysics, fusion, high-energy or medical, radiation transport in general benefit notably from such enhanced libraries. It is particularly noticeable in term of the number of isotopes, materials available, the overall quality of the data and the much broader energy range for which evaluated (as opposed to modeled) data are available, spanning from meV to hundreds of MeV. In pointing out the impact of the different nuclear data at the library but also the isotopic levels one could not help

The Los Alamos Neutron Science Center Spallation Neutron Sources

NASA Astrophysics Data System (ADS)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutrons are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ∼100 keV. The characteristics of these sources, and

The Los Alamos Neutron Science Center Spallation Neutron Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutronsmore » are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

The Los Alamos Neutron Science Center Spallation Neutron Sources

DOE PAGES

Nowicki, Suzanne F.; Wender, Stephen A.; Mocko, Michael

2017-10-26

The Los Alamos Neutron Science Center (LANSCE) provides the scientific community with intense sources of neutrons, which can be used to perform experiments supporting civilian and national security research. These measurements include nuclear physics experiments for the defense program, basic science, and the radiation effect programs. This paper focuses on the radiation effects program, which involves mostly accelerated testing of semiconductor parts. When cosmic rays strike the earth's atmosphere, they cause nuclear reactions with elements in the air and produce a wide range of energetic particles. Because neutrons are uncharged, they can reach aircraft altitudes and sea level. These neutronsmore » are thought to be the most important threat to semiconductor devices and integrated circuits. The best way to determine the failure rate due to these neutrons is to measure the failure rate in a neutron source that has the same spectrum as those produced by cosmic rays. Los Alamos has a high-energy and a low-energy neutron source for semiconductor testing. Both are driven by the 800-MeV proton beam from the LANSCE accelerator. The high-energy neutron source at the Weapons Neutron Research (WNR) facility uses a bare target that is designed to produce fast neutrons with energies from 100 keV to almost 800 MeV. The measured neutron energy distribution from WNR is very similar to that of the cosmic-ray-induced neutrons in the atmosphere. However, the flux provided at the WNR facility is typically 5×107 times more intense than the flux of the cosmic-ray-induced neutrons. This intense neutron flux allows testing at greatly accelerated rates. An irradiation test of less than an hour is equivalent to many years of neutron exposure due to cosmic-ray neutrons. The low-energy neutron source is located at the Lujan Neutron Scattering Center. It is based on a moderated source that provides useful neutrons from subthermal energies to ~100 keV. The characteristics of these sources

Biological Assessment of the Continued Operation of Los Alamos National Laboratory on Federally Listed Threatened and Endangered Species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Leslie A.

2006-09-19

This biological assessment considers the effects of continuing to operate Los Alamos National Laboratory on Federally listed threatened or endangered species, based on current and future operations identified in the 2006 Site-wide Environmental Impact Statement for the Continued Operation of Los Alamos National Laboratory (SWEIS; DOE In Prep.). We reviewed 40 projects analyzed in the SWEIS as well as two aspects on ongoing operations to determine if these actions had the potential to affect Federally listed species. Eighteen projects that had not already received U.S. Fish and Wildlife Service (USFWS) consultation and concurrence, as well as the two aspects ofmore » ongoing operations, ecological risk from legacy contaminants and the Outfall Reduction Project, were determined to have the potential to affect threatened or endangered species. Cumulative impacts were also analyzed.« less

The Los ALamos Neutron Science Center Hydrogen Moderator System

NASA Astrophysics Data System (ADS)

Jarmer, J. J.; Knudson, J. N.

2006-04-01

At the Los Alamos Neutron Science Center (LANSCE), spallation neutrons are produced by an 800-MeV proton beam interacting with tungsten targets. Gun-barrel-type penetrations through the heavy concrete and steel shielding that surround the targets collimate neutrons to form neutron beams used for scattering experiments. Two liquid hydrogen moderators of one-liter volume each are positioned adjacent to the neutron-production targets. Some of the neutrons that pass through a moderator interact with or scatter from protons in the hydrogen. The neutron-proton interaction reduces the energy or moderates neutrons to lower energies. Lower energy "moderated" neutrons are the most useful for some neutron scattering experiments. We provide a description of the LANSCE hydrogen-moderator system and its cryogenic performance with proton beams of up to 125 micro-amp average current.

Space Science at Los Alamos National Laboratory

NASA Astrophysics Data System (ADS)

Smith, Karl

2017-09-01

The Space Science and Applications group (ISR-1) in the Intelligence and Space Research (ISR) division at the Los Alamos National Laboratory lead a number of space science missions for civilian and defense-related programs. In support of these missions the group develops sensors capable of detecting nuclear emissions and measuring radiations in space including γ-ray, X-ray, charged-particle, and neutron detection. The group is involved in a number of stages of the lifetime of these sensors including mission concept and design, simulation and modeling, calibration, and data analysis. These missions support monitoring of the atmosphere and near-Earth space environment for nuclear detonations as well as monitoring of the local space environment including space-weather type events. Expertise in this area has been established over a long history of involvement with cutting-edge projects continuing back to the first space based monitoring mission Project Vela. The group's interests cut across a large range of topics including non-proliferation, space situational awareness, nuclear physics, material science, space physics, astrophysics, and planetary physics.

Threatened and Endangered Species Habitat Management Plan for Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hathcock, Charles Dean; Keller, David Charles; Thompson, Brent E.

Los Alamos National Laboratory’s (LANL) Threatened and Endangered Species Habitat Management Plan (HMP) fulfills a commitment made to the U.S. Department of Energy (DOE) in the “Final Environmental Impact Statement for the Dual-Axis Radiographic Hydrodynamic Test Facility Mitigation Action Plan” (DOE 1996). The HMP received concurrence from the U.S. Fish and Wildlife Service (USFWS) in 1999 (USFWS consultation numbers 2-22-98-I-336 and 2-22-95-I-108). This 2017 update retains the management guidelines from the 1999 HMP for listed species, and updates some descriptive information.

New facility for ion beam materials characterization and modification at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tesmer, J.R.; Maggiore, C.J.; Parkin, D.M.

1988-01-01

The Ion Beam Materials Laboratory (IBML) is a new Los Alamos laboratory devoted to the characterization and modification of the near surfaces of materials. The primary instruments of the IBML are a tandem electrostatic accelerator, a National Electrostatics Corp. Model 9SDH, coupled with a Varian CF-3000 ion implanter. The unique organizational structure of the IBML as well as the operational characteristics of the 9SDH (after approximately 3000 h of operation) and the laboratories' research capabilities will be discussed. Examples of current research results will also be presented. 5 refs., 2 figs.

Critical experiments at Sandia National Laboratories : technical meeting on low-power critical facilities and small reactors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harms, Gary A.; Ford, John T.; Barber, Allison Delo

2010-11-01

Sandia National Laboratories (SNL) has conducted radiation effects testing for the Department of Energy (DOE) and other contractors supporting the DOE since the 1960's. Over this period, the research reactor facilities at Sandia have had a primary mission to provide appropriate nuclear radiation environments for radiation testing and qualification of electronic components and other devices. The current generation of reactors includes the Annular Core Research Reactor (ACRR), a water-moderated pool-type reactor, fueled by elements constructed from UO2-BeO ceramic fuel pellets, and the Sandia Pulse Reactor III (SPR-III), a bare metal fast burst reactor utilizing a uranium-molybdenum alloy fuel. The SPR-IIImore » is currently defueled. The SPR Facility (SPRF) has hosted a series of critical experiments. A purpose-built critical experiment was first operated at the SPRF in the late 1980's. This experiment, called the Space Nuclear Thermal Propulsion Critical Experiment (CX), was designed to explore the reactor physics of a nuclear thermal rocket motor. This experiment was fueled with highly-enriched uranium carbide fuel in annular water-moderated fuel elements. The experiment program was completed and the fuel for the experiment was moved off-site. A second critical experiment, the Burnup Credit Critical Experiment (BUCCX) was operated at Sandia in 2002. The critical assembly for this experiment was based on the assembly used in the CX modified to accommodate low-enriched pin-type fuel in water moderator. This experiment was designed as a platform in which the reactivity effects of specific fission product poisons could be measured. Experiments were carried out on rhodium, an important fission product poison. The fuel and assembly hardware for the BUCCX remains at Sandia and is available for future experimentation. The critical experiment currently in operation at the SPRF is the Seven Percent Critical Experiment (7uPCX). This experiment is designed to provide

Alignment and assembly process for primary mirror subsystem of a spaceborne telescope

NASA Astrophysics Data System (ADS)

Lin, Wei-Cheng; Chang, Shenq-Tsong; Chang, Sheng-Hsiung; Chang, Chen-Peng; Lin, Yu-Chuan; Chin, Chi-Chieh; Pan, Hsu-Pin; Huang, Ting-Ming

2015-11-01

In this study, a multispectral spaceborne Cassegrain telescope was developed. The telescope was equipped with a primary mirror with a 450-mm clear aperture composed of Zerodur and lightweighted at a ratio of approximately 50% to meet both thermal and mass requirements. Reducing the astigmatism was critical for this mirror. The astigmatism is caused by gravity effects, the bonding process, and deformation from mounting the main structure of the telescope (main plate). This article presents the primary mirror alignment, mechanical ground-supported equipment (MGSE), assembly process, and optical performance test used to assemble the primary mirror. A mechanical compensated shim is used as the interface between the bipod flexure and main plate. The shim was used to compensate for manufacturer errors found in components and differences between local coplanarity errors to prevent stress while the bipod flexure was screwed to the main plate. After primary mirror assembly, an optical performance test method called a bench test with an algorithm was used to analyze the astigmatism caused by the gravity effect and deformation from the mounting or supporter. The tolerance conditions for the primary mirror assembly require the astigmatism caused by gravity and mounting force deformation to be less than P-V 0.02 λ at 632.8 nm. The results demonstrated that the designed MGSE used in the alignment and assembly processes met the critical requirements for the primary mirror assembly of the telescope.

An experimental topographic amplification study at Los Alamos National Laboratory using ambient vibrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolte, Andrew C.; Cox, Brady R.; Lee, Richard C.

An experimental study aimed at investigating potential topographic amplification of seismic waves was conducted on a 50-m-tall and 185-m-wide soft-rock ridge located at Los Alamos National Laboratory near Los Alamos, New Mexico. Ten portable broadband seismograph stations were placed in arrays across the ridge and left to record ambient vibration data for ~9 hours. Clear evidence of topographic amplification was observed by comparing spectral ratios calculated from ambient noise recordings at the toe, slope, and crest of the instrumented ridge. The inferred resonance frequency of the ridge obtained from the experimental recordings was found to agree well with several simplemore » estimates of the theoretical resonance frequency based on its geometry and stiffness. Results support the feasibility of quantifying the frequency range of topographic amplification solely using ambient vibrations, rather than strong or weak ground motions. Additionally, comparisons have been made between a number of widely used experimental methods for quantifying topographic effects, such as the standard spectral ratio, median reference method, and horizontal-to-vertical spectral ratio. As a result, differences in the amplification and frequency range of topographic effects indicated by these methods highlight the importance of choosing a reference condition that is appropriate for the site-specific conditions and goals associated with an experimental topographic amplification study.« less

An experimental topographic amplification study at Los Alamos National Laboratory using ambient vibrations

DOE PAGES

Stolte, Andrew C.; Cox, Brady R.; Lee, Richard C.

2017-03-14

An experimental study aimed at investigating potential topographic amplification of seismic waves was conducted on a 50-m-tall and 185-m-wide soft-rock ridge located at Los Alamos National Laboratory near Los Alamos, New Mexico. Ten portable broadband seismograph stations were placed in arrays across the ridge and left to record ambient vibration data for ~9 hours. Clear evidence of topographic amplification was observed by comparing spectral ratios calculated from ambient noise recordings at the toe, slope, and crest of the instrumented ridge. The inferred resonance frequency of the ridge obtained from the experimental recordings was found to agree well with several simplemore » estimates of the theoretical resonance frequency based on its geometry and stiffness. Results support the feasibility of quantifying the frequency range of topographic amplification solely using ambient vibrations, rather than strong or weak ground motions. Additionally, comparisons have been made between a number of widely used experimental methods for quantifying topographic effects, such as the standard spectral ratio, median reference method, and horizontal-to-vertical spectral ratio. As a result, differences in the amplification and frequency range of topographic effects indicated by these methods highlight the importance of choosing a reference condition that is appropriate for the site-specific conditions and goals associated with an experimental topographic amplification study.« less

Self-assembled nanolaminate coatings (SV)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, H.

2012-03-01

Sandia National Laboratories (Sandia) and Lockheed Martin Aeronautics (LM Aero) are collaborating to develop affordable, self-assembled, nanocomposite coatings and associated fabrication processes that will be tailored to Lockheed Martin product requirements. The purpose of this project is to develop a family of self-assembled coatings with properties tailored to specific performance requirements, such as antireflective (AR) optics, using Sandia-developed self-assembled techniques. The project met its objectives by development of a simple and economic self-assembly processes to fabricate multifunctional coatings. Specifically, materials, functionalization methods, and associated coating processes for single layer and multiple layers coatings have been developed to accomplish high reflectivemore » coatings, hydrophobic coatings, and anti-reflective coatings. Associated modeling and simulations have been developed to guide the coating designs for optimum optical performance. The accomplishments result in significant advantages of reduced costs, increased manufacturing freedom/producibility, improved logistics, and the incorporation of new technology solutions not possible with conventional technologies. These self-assembled coatings with tailored properties will significantly address LMC's needs and give LMC a significant competitive lead in new engineered materials. This work complements SNL's LDRD and BES programs aimed at developing multifunctional nanomaterials for microelectronics and optics as well as structure/property investigations of self-assembled nanomaterials. In addition, this project will provide SNL with new opportunities to develop and apply self-assembled nanocomposite optical coatings for use in the wavelength ranges of 3-5 and 8-12 micrometers, ranges of vital importance to military-based sensors and weapons. The SANC technologies will be applied to multiple programs within the LM Company including the F-35, F-22, ADP (Future Strike Bomber, UAV

Nuclear reactor removable radial shielding assembly having a self-bowing feature

DOEpatents

Pennell, William E.; Kalinowski, Joseph E.; Waldby, Robert N.; Rylatt, John A.; Swenson, Daniel V.

1978-01-01

A removable radial shielding assembly for use in the periphery of the core of a liquid-metal-cooled fast-breeder reactor, for closing interassembly gaps in the reactor core assembly load plane prior to reactor criticality and power operation to prevent positive reactivity insertion. The assembly has a lower nozzle portion for inserting into the core support and a flexible heat-sensitive bimetallic central spine surrounded by blocks of shielding material. At refueling temperature and below the spine is relaxed and in a vertical position so that the tolerances permitted by the interassembly gaps allow removal and replacement of the various reactor core assemblies. During an increase in reactor temperature from refueling to hot standby, the bimetallic spine expands, bowing the assembly toward the core center line, exerting a radially inward gap-closing-force on the above core load plane of the reactor core assembly, closing load plane interassembly gaps throughout the core prior to startup and preventing positive reactivity insertion.

Mars aerobrake assembly simulation

NASA Technical Reports Server (NTRS)

Filatovs, G. J.; Lee, Gordon K. F.; Garvey, John

1992-01-01

On-orbit assembly operation simulations in neutral buoyancy conditions are presently undertaken by a partial/full-scale Mars mission aerobrake mockup, whose design, conducted in the framework of an engineering senior students' design project, involved several levels of constraints for critical physical and operational features. Allowances had to be made for the auxiliary constraints introduced by underwater testing, as well as the subsegmenting required for overland shipment to the neutral-buoyancy testing facility. This mockup aerobrake's fidelity is determined by the numerous, competing design objectives.

CSM docked DAP/orbital assembly bending interaction-axial case

NASA Technical Reports Server (NTRS)

Turnbull, J. F.; Jones, J. E.

1972-01-01

A digital autopilot which can provide attitude control for the entire Skylab orbital assembly using the service module reaction control jets is described. An important consideration is the potential interaction of the control system with the bending modes of the orbital assembly. Two aspects of this potential interaction were considered. The first was the possibility that bending induced rotations feeding back through the attitude sensor into the control system could produce an instability or self-sustained oscillation. The second was whether the jet activity commanded by the control system could produce excessive loads at any of the critical load points of the orbital assembly. Both aspects were studied by using analytic techniques and by running simulations on the all-digital simulator.

76 FR 62330 - Radio Broadcasting Services; Alamo, GA; Alton, MO; Boscobel, WI; Buffalo, OK; Cove, AR; Clayton...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-07

... Broadcasting Services; Alamo, GA; Alton, MO; Boscobel, WI; Buffalo, OK; Cove, AR; Clayton, LA; Daisy, AR; Ennis... competitive bidding process, and are considered unsold permits that were included in Auction 91. Interested... competitive bidding process. DATES: Comments must be filed on or before October 31, 2011, and reply comments...

Statistical analyses of the background distribution of groundwater solutes, Los Alamos National Laboratory, New Mexico.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longmire, Patrick A.; Goff, Fraser; Counce, D. A.

2004-01-01

Background or baseline water chemistry data and information are required to distingu ish between contaminated and non-contaminated waters for environmental investigations conducted at Los Alamos National Laboratory (referred to as the Laboratory). The term 'background' refers to natural waters discharged by springs or penetrated by wells that have not been contaminated by LANL or other municipal or industrial activities, and that are representative of groundwater discharging from their respective aquifer material. These investigations are conducted as part of the Environmental Restoration (ER) Project, Groundwater Protection Program (GWPP), Laboratory Surveillance Program, the Hydrogeologic Workplan, and the Site-Wide Environmental Impact Statement (SWEIS).more » This poster provides a comprehensive, validated database of inorganic, organic, stable isotope, and radionuclide analyses of up to 136 groundwater samples collected from 15 baseline springs and wells located in and around Los Alamos National Laboratory, New Mexico. The region considered in this investigation extends from the western edge of the Jemez Mountains eastward to the Rio Grande and from Frijoles Canyon northward to Garcia Canyon. Figure 1 shows the fifteen stations sampled for this investigation. The sampling stations and associated aquifer types are summarized in Table 1.« less

Climate Change and the Los Alamos National Laboratory. The Adaptation Challenge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, Kimberly M.; Hjeresen, Dennis; Silverman, Josh

2015-02-01

The Los Alamos National Laboratory (LANL) has been adapting to climate change related impacts that have been occurring on decadal time scales. The region where LANL is located has been subject to a cascade of climate related impacts: drought, devastating wildfires, and historic flooding events. Instead of buckling under the pressure, LANL and the surrounding communities have integrated climate change mitigation strategies into their daily operations and long-term plans by increasing coordination and communication between the Federal, State, and local agencies in the region, identifying and aggressively managing forested areas in need of near-term attention, addressing flood control and retentionmore » issues, and more.« less

Dismantlement of the TSF-SNAP Reactor Assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peretz, Fred J

2009-01-01

This paper describes the dismantlement of the Tower Shielding Facility (TSF)?Systems for Nuclear Auxiliary Power (SNAP) reactor, a SNAP-10A reactor used to validate radiation source terms and shield performance models at Oak Ridge National Laboratory (ORNL) from 1967 through 1973. After shutdown, it was placed in storage at the Y-12 National Security Complex (Y-12), eventually falling under the auspices of the Highly Enriched Uranium (HEU) Disposition Program. To facilitate downblending of the HEU present in the fuel elements, the TSF-SNAP was moved to ORNL on June 24, 2006. The reactor assembly was removed from its packaging, inspected, and the sodium-potassiummore » (NaK) coolant was drained. A superheated steam process was used to chemically react the residual NaK inside the reactor assembly. The heat exchanger assembly was removed from the top of the reactor vessel, and the criticality safety sleeve was exchanged for a new safety sleeve that allowed for the removal of the vessel lid. A chain-mounted tubing cutter was used to separate the lid from the vessel, and the 36 fuel elements were removed and packaged in four U.S. Department of Transportation 2R/6M containers. The fuel elements were returned to Y-12 on July 13, 2006. The return of the fuel elements and disposal of all other reactor materials accomplished the formal objectives of the dismantlement project. In addition, a project model was established for the handling of a fully fueled liquid-metal?cooled reactor assembly. Current criticality safety codes have been benchmarked against experiments performed by Atomics International in the 1950s and 1960s. Execution of this project provides valuable experience applicable to future projects addressing space and liquid-metal-cooled reactors.« less

Multilayer block copolymer meshes by orthogonal self-assembly

PubMed Central

Tavakkoli K. G., Amir; Nicaise, Samuel M.; Gadelrab, Karim R.; Alexander-Katz, Alfredo; Ross, Caroline A.; Berggren, Karl K.

2016-01-01

Continued scaling-down of lithographic-pattern feature sizes has brought templated self-assembly of block copolymers (BCPs) into the forefront of nanofabrication research. Technologies now exist that facilitate significant control over otherwise unorganized assembly of BCP microdomains to form both long-range and locally complex monolayer patterns. In contrast, the extension of this control into multilayers or 3D structures of BCP microdomains remains limited, despite the possible technological applications in next-generation devices. Here, we develop and analyse an orthogonal self-assembly method in which multiple layers of distinct-molecular-weight BCPs naturally produce nanomesh structures of cylindrical microdomains without requiring layer-by-layer alignment or high-resolution lithographic templating. The mechanisms for orthogonal self-assembly are investigated with both experiment and simulation, and we determine that the control over height and chemical preference of templates are critical process parameters. The method is employed to produce nanomeshes with the shapes of circles and Y-intersections, and is extended to produce three layers of orthogonally oriented cylinders. PMID:26796218

Recreating America's Community Colleges: Critical Policy Issues Facing America's Community Colleges

ERIC Educational Resources Information Center

Honeyman, David S.; Sullivan, Michael D.

2006-01-01

During the conduct of the 2004 Community Colleges Futures Assembly, sponsored by the University of Florida, delegates to the meeting identified three critical policy issues facing America's community colleges and challenged the delegates attending the 2005 Assembly to debate these issues and make recommendations. A total of 252 higher-education…

Block copolymer self-assembly-directed synthesis of mesoporous gyroidal superconductors.

PubMed

Robbins, Spencer W; Beaucage, Peter A; Sai, Hiroaki; Tan, Kwan Wee; Werner, Jörg G; Sethna, James P; DiSalvo, Francis J; Gruner, Sol M; Van Dover, Robert B; Wiesner, Ulrich

2016-01-01

Superconductors with periodically ordered mesoporous structures are expected to have properties very different from those of their bulk counterparts. Systematic studies of such phenomena to date are sparse, however, because of a lack of versatile synthetic approaches to such materials. We demonstrate the formation of three-dimensionally continuous gyroidal mesoporous niobium nitride (NbN) superconductors from chiral ABC triblock terpolymer self-assembly-directed sol-gel-derived niobium oxide with subsequent thermal processing in air and ammonia gas. Superconducting materials exhibit a critical temperature (T c) of about 7 to 8 K, a flux exclusion of about 5% compared to a dense NbN solid, and an estimated critical current density (J c) of 440 A cm(-2) at 100 Oe and 2.5 K. We expect block copolymer self-assembly-directed mesoporous superconductors to provide interesting subjects for mesostructure-superconductivity correlation studies.

Los Alamos nEDM Experiment and Demonstration of Ramsey's Method on Stored UCNs at the LANL UCN Source

NASA Astrophysics Data System (ADS)

Clayton, Steven; Chupp, Tim; Cude-Woods, Christopher; Currie, Scott; Ito, Takeyasu; Liu, Chen-Yu; Long, Joshua; MacDonald, Stephen; Makela, Mark; O'Shaughnessy, Christopher; Plaster, Brad; Ramsey, John; Saunders, Andy; LANL nEDM Collaboration

2017-09-01

The Los Alamos National Laboratory ultracold neutron (UCN) source was recently upgraded for a factor of 5 improvement in stored density, providing the statistical precision needed for a room temperature neutron electric dipole moment measurement with sensitivity 3 ×10-27 e . cm, a factor 10 better than the limit set by the Sussex-RAL-ILL experiment. Here, we show results of a demonstration of Ramsey's separated oscillatory fields method on stored UCNs at the LANL UCN source and in a geometry relevant for a nEDM measurement. We argue a world-leading nEDM experiment could be performed at LANL with existing technology and a short lead time, providing a physics result with sensitivity intermediate between the current limit set by Sussex-RAL-ILL, and the anticipated limit from the complex, cryogenic nEDM experiment planned for the next decade at the ORNL Spallation Neutron Source (SNS-nEDM). This work was supported by the Los Alamos LDRD Program, Project 20140015DR.

Availability of environmental radioactivity to honey bee colonies at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hakonson, T.E.; Bostick, K.V.

Data are presented on the availability of tritium, cesium 137, and plutonium to honey bee colonies foraging in the environment surrounding the Los Alamos Scientific Laboratory. Sources of these radionuclides in the laboratory environs include liquid and atmospheric effluents and buried solid waste. Honey bee colonies were placed in three canyon liquid waste disposal areas and were sampled frequently, along with honey, surface water, and surrounding vegetation, to qualitatively determine the availability of these radionuclides to bees (Apis mellifera) and to identify potential food chain sources of the elements. Tritium concentrations in bee and honey samples from the canyons increasedmore » rapidly from initial values of <1 pCi/ml moisture to as much as 9.2 nCi/ml in 75 days after placement of the hives in the canyons. Seasonal patterns in foraging activities as influenced by weather and food availability were apparent in the data. It appears that several sources of tritium were utilized by the colonies, including surface water in the canyons and vegetation receiving tritium from atmospheric effluents and buried solid waste. Concentrations of cesium 137 and plutonium were generally low or undetectable in bees throughout the study. However, levels of both nuclides increased by factors of 10 to 20 in bees from two of the canyon study areas during a 3-month period in 1973. It was speculated that the liquid effluents in the two canyons were the source of the increased concentrations in bee samples, since this water was the only significant source of /sup 137/Cs in the environs. The existence of at least three radionuclide sources in the Los Alamos Scientific Laboratory (LASL) environs complicates the interpretation of the data. However, it is apparent that honey bees can acquire /sup 3/H, /sup 137/Cs, and Pu from multiple sources in the environs.« less

2015 Los Alamos Space Weather Summer School Research Reports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cowee, Misa; Chen, Yuxi; Desai, Ravindra

The fifth Los Alamos Space Weather Summer School was held June 1st - July 24th, 2015, at Los Alamos National Laboratory (LANL). With renewed support from the Institute of Geophysics, Planetary Physics, and Signatures (IGPPS) and additional support from the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) Office of Science, we hosted a new class of five students from various U.S. and foreign research institutions. The summer school curriculum includes a series of structured lectures as well as mentored research and practicum opportunities. Lecture topics including general and specialized topics in the field of spacemore » weather were given by a number of researchers affiliated with LANL. Students were given the opportunity to engage in research projects through a mentored practicum experience. Each student works with one or more LANL-affiliated mentors to execute a collaborative research project, typically linked with a larger ongoing research effort at LANL and/or the student’s PhD thesis research. This model provides a valuable learning experience for the student while developing the opportunity for future collaboration. This report includes a summary of the research efforts fostered and facilitated by the Space Weather Summer School. These reports should be viewed as work-in-progress as the short session typically only offers sufficient time for preliminary results. At the close of the summer school session, students present a summary of their research efforts. Titles of the papers included in this report are as follows: Full particle-in-cell (PIC) simulation of whistler wave generation, Hybrid simulations of the right-hand ion cyclotron anisotropy instability in a sub-Alfvénic plasma flow, A statistical ensemble for solar wind measurements, Observations and models of substorm injection dispersion patterns, Heavy ion effects on Kelvin-Helmholtz instability: hybrid study, Simulating plasmaspheric electron densities with

Reactor Testing and Qualification: Prioritized High-level Criticality Testing Needs

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. Bragg-Sitton; J. Bess; J. Werner

2011-09-01

Researchers at the Idaho National Laboratory (INL) were tasked with reviewing possible criticality testing needs to support development of the fission surface power system reactor design. Reactor physics testing can provide significant information to aid in development of technologies associated with small, fast spectrum reactors that could be applied for non-terrestrial power systems, leading to eventual system qualification. Several studies have been conducted in recent years to assess the data and analyses required to design and build a space fission power system with high confidence that the system will perform as designed [Marcille, 2004a, 2004b; Weaver, 2007; Parry et al.,more » 2008]. This report will provide a summary of previous critical tests and physics measurements that are potentially applicable to the current reactor design (both those that have been benchmarked and those not yet benchmarked), summarize recent studies of potential nuclear testing needs for space reactor development and their applicability to the current baseline fission surface power (FSP) system design, and provide an overview of a suite of tests (separate effects, sub-critical or critical) that could fill in the information database to improve the accuracy of physics modeling efforts as the FSP design is refined. Some recommendations for tasks that could be completed in the near term are also included. Specific recommendations on critical test configurations will be reserved until after the sensitivity analyses being conducted by Los Alamos National Laboratory (LANL) are completed (due August 2011).« less

Characterization of the Arabidopsis Augmin Complex Uncovers Its Critical Function in the Assembly of the Acentrosomal Spindle and Phragmoplast Microtubule Arrays[W

PubMed Central

Hotta, Takashi; Kong, Zhaosheng; Ho, Chin-Min Kimmy; Zeng, Cui Jing Tracy; Horio, Tetsuya; Fong, Sophia; Vuong, Trang; Lee, Yuh-Ru Julie; Liu, Bo

2012-01-01

Plant cells assemble the bipolar spindle and phragmoplast microtubule (MT) arrays in the absence of the centrosome structure. Our recent findings in Arabidopsis thaliana indicated that AUGMIN subunit3 (AUG3), a homolog of animal dim γ-tubulin 3, plays a critical role in γ-tubulin–dependent MT nucleation and amplification during mitosis. Here, we report the isolation of the entire plant augmin complex that contains eight subunits. Among them, AUG1 to AUG6 share low sequence similarity with their animal counterparts, but AUG7 and AUG8 share homology only with proteins of plant origin. Genetic analyses indicate that the AUG1, AUG2, AUG4, and AUG5 genes are essential, as stable mutations in these genes could only be transmitted to heterozygous plants. The sterile aug7-1 homozygous mutant in which AUG7 expression is significantly reduced exhibited pleiotropic phenotypes of seriously retarded vegetative and reproductive growth. The aug7-1 mutation caused delocalization of γ-tubulin in the mitotic spindle and phragmoplast. Consequently, spindles were abnormally elongated, and their poles failed to converge, as MTs were splayed to discrete positions rendering deformed arrays. In addition, the mutant phragmoplasts often had disorganized MT bundles with uneven edges. We conclude that assembly of MT arrays during plant mitosis depends on the augmin complex, which includes two plant-specific subunits. PMID:22505726

Evaluation of aircraft crash hazard at Los Alamos National Laboratory facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Selvage, R.D.

This report selects a method for use in calculating the frequency of an aircraft crash occurring at selected facilities at the Los Alamos National Laboratory (the Laboratory). The Solomon method was chosen to determine these probabilities. Each variable in the Solomon method is defined and a value for each variable is selected for fourteen facilities at the Laboratory. These values and calculated probabilities are to be used in all safety analysis reports and hazards analyses for the facilities addressed in this report. This report also gives detailed directions to perform aircraft-crash frequency calculations for other facilities. This will ensure thatmore » future aircraft-crash frequency calculations are consistent with calculations in this report.« less

GFinisher: a new strategy to refine and finish bacterial genome assemblies

NASA Astrophysics Data System (ADS)

Guizelini, Dieval; Raittz, Roberto T.; Cruz, Leonardo M.; Souza, Emanuel M.; Steffens, Maria B. R.; Pedrosa, Fabio O.

2016-10-01

Despite the development in DNA sequencing technology, improving the number and the length of reads, the process of reconstruction of complete genome sequences, the so called genome assembly, is still complex. Only 13% of the prokaryotic genome sequencing projects have been completed. Draft genome sequences deposited in public databases are fragmented in contigs and may lack the full gene complement. The aim of the present work is to identify assembly errors and improve the assembly process of bacterial genomes. The biological patterns observed in genomic sequences and the application of a priori information can allow the identification of misassembled regions, and the reorganization and improvement of the overall de novo genome assembly. GFinisher starts generating a Fuzzy GC skew graphs for each contig in an assembly and follows breaking down the contigs in critical points in order to reassemble and close them using jFGap. This has been successfully applied to dataset from 96 genome assemblies, decreasing the number of contigs by up to 86%. GFinisher can easily optimize assemblies of prokaryotic draft genomes and can be used to improve the assembly programs based on nucleotide sequence patterns in the genome. The software and source code are available at http://gfinisher.sourceforge.net/.

GFinisher: a new strategy to refine and finish bacterial genome assemblies.

PubMed

Guizelini, Dieval; Raittz, Roberto T; Cruz, Leonardo M; Souza, Emanuel M; Steffens, Maria B R; Pedrosa, Fabio O

2016-10-10

Despite the development in DNA sequencing technology, improving the number and the length of reads, the process of reconstruction of complete genome sequences, the so called genome assembly, is still complex. Only 13% of the prokaryotic genome sequencing projects have been completed. Draft genome sequences deposited in public databases are fragmented in contigs and may lack the full gene complement. The aim of the present work is to identify assembly errors and improve the assembly process of bacterial genomes. The biological patterns observed in genomic sequences and the application of a priori information can allow the identification of misassembled regions, and the reorganization and improvement of the overall de novo genome assembly. GFinisher starts generating a Fuzzy GC skew graphs for each contig in an assembly and follows breaking down the contigs in critical points in order to reassemble and close them using jFGap. This has been successfully applied to dataset from 96 genome assemblies, decreasing the number of contigs by up to 86%. GFinisher can easily optimize assemblies of prokaryotic draft genomes and can be used to improve the assembly programs based on nucleotide sequence patterns in the genome. The software and source code are available at http://gfinisher.sourceforge.net/.

Environmental surveillance and compliance at Los Alamos during 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1997-09-01

This report presents environmental data that characterize environmental performance and addresses compliance with environmental standards and requirements at Los Alamos National Laboratory (LANL or the Laboratory) during 1996. The Laboratory routinely monitors for radiation and for radioactive nonradioactive materials at Laboratory sites as well as in the surrounding region. LANL uses the monitoring results to determine compliance with appropriate standards and to identify potentially undesirable trends. Data were collected in 1996 to assess external penetrating radiation; quantities of airborne emissions; and concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, the municipal water supply, soils and sediments,more » and foodstuffs. Using comparisons with standards and regulations, this report concludes that environmental effects from Laboratory operations are small and do not pose a demonstrable threat to the public, Laboratory employees, or the environment. Laboratory operations were in compliance with all major environmental regulations.« less

Los Alamos National Laboratory Science Education Programs. Progress report, October 1, 1994--December 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gill, D.H.

During the 1994 summer institute NTEP teachers worked in coordination with LANL and the Los Alamos Middle School and Mountain Elementary School to gain experience in communicating on-line, to gain further information from the Internet and in using electronic Bulletin Board Systems (BBSs) to exchange ideas with other teachers. To build on their telecommunications skills, NTEP teachers participated in the International Telecommunications In Education Conference (Tel*ED `94) at the Albuquerque Convention Center on November 11 & 12, 1994. They attended the multimedia keynote address, various workshops highlighting many aspects of educational telecommunications skills, and the Telecomm Rodeo sponsored by Losmore » Alamos National Laboratory. The Rodeo featured many presentations by Laboratory personnel and educational institutions on ways in which telecommunications technologies can be use din the classroom. Many were of the `hands-on` type, so that teachers were able to try out methods and equipment and evaluate their usefulness in their own schools and classrooms. Some of the presentations featured were the Geonet educational BBS system, the Supercomputing Challenge, and the Sunrise Project, all sponsored by LANL; the `CU-seeMe` live video software, various simulation software packages, networking help, and many other interesting and useful exhibits.« less

Beam Loss Measurements at the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Spickermann, Thomas

2005-06-01

During normal operation the Los Alamos Proton Storage Ring (PSR) accumulates up to 4ṡ1013 protons over 625μs with a repetition rate of 20 Hz, corresponding to a current of 125μA to the Lujan Neutron Science Center. Beam losses in the ring as well as in the extraction beam line and the subsequent activation of material are a limiting factor at these currents. Careful tuning of injection, ring and extraction line is paramount to limiting losses to acceptable levels. Losses are typically not uniform around the ring, but occur in significantly higher levels in certain "hot spots". Here I will report on losses related to the stripper foil which are the dominant source of losses in the ring. First results of a comparison with simulations will also be presented.

Neutron Capture Experiments Using the DANCE Array at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dashdorj, D.; MonAme Scientific Research Center, Ulaanbaatar; Mitchell, G. E.

2009-03-31

The Detector for Advanced Neutron Capture Experiments (DANCE) is designed for neutron capture measurements on very small and/or radioactive targets. The DANCE array of 160 BaF{sub 2} scintillation detectors is located at the Lujan Center at the Los Alamos Neutron Science Center (LANSCE). Accurate measurements of neutron capture data are important for many current applications as well as for basic understanding of neutron capture. The gamma rays following neutron capture reactions have been studied by the time-of-flight technique using the DANCE array. The high granularity of the array allows measurements of the gamma-ray multiplicity. The gamma-ray multiplicities and energy spectramore » for different multiplicities can be measured and analyzed for spin and parity determination of the resolved resonances.« less

The Los Alamos Scientific Laboratory - An Isolated Nuclear Research Establishment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradbury, Norris E.; Meade, Roger Allen

Early in his twenty-five year career as the Director of the Los Alamos Scientific Laboratory, Norris Bradbury wrote at length about the atomic bomb and the many implications the bomb might have on the world. His themes were both technical and philosophical. In 1963, after nearly twenty years of leading the nation’s first nuclear weapons laboratory, Bradbury took the opportunity to broaden his writing. In a paper delivered to the International Atomic Energy Agency’s symposium on the “Criteria in the Selection of Sites for the Construction of Reactors and Nuclear Research Centers,” Bradbury took the opportunity to talk about themore » business of nuclear research and the human component of operating a scientific laboratory. This report is the transcript of his talk.« less

Common ground: An environmental ethic for Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menlove, F.L.

1991-01-01

Three predominant philosophies have characterized American business ethical thinking over the past several decades. The first phase is the ethics of self-interest'' which argues that maximizing self-interest coincidentally maximizes the common good. The second phase is legality ethics.'' Proponents argue that what is important is knowing the rules and following them scrupulously. The third phase might be called stake-holder ethics.'' A central tenant is that everyone affected by a decision has a moral hold on the decision maker. This paper will discuss one recent initiative of the Los Alamos National Laboratory to move beyond rules and regulations toward an environmentalmore » ethic that integrates the values of stakeholder ethics'' into the Laboratory's historical culture and value systems. These Common Ground Principles are described. 11 refs.« less

Neutron spectrum determination in a sub-critical assembly using the multi-disc neutron activation technique

NASA Astrophysics Data System (ADS)

Koseoglou, P.; Vagena, E.; Stoulos, S.; Manolopoulou, M.

2016-09-01

Neutron spectrum of the sub-critical nuclear assembly-reactor of Aristotle University of Thessaloniki was measured at three radial distances from the reactor core. The neutron activation technique was applied irradiating 15 thick foils - disc of various elements at each position. The data of 38 (n, γ), (n, p) and (n, α) reactions were analyzed for specific activity determination. Discs instead of foils were used due to the relevant low neutron flux, so the gamma self-absorption as well as the neutron self-shielding factors has been calculated using GEANT simulations in order to determine the activity induced. The specific activities calculated for all isotopes studied were the input to the SANDII code, which was built specifically for the neutron spectrum de-convolution when the neutron activation technique is used. For the optimization of the results a technique was applied in order to minimize the influence of the initial-"guessed" spectrum shape SANDII uses. The neutron spectrum estimated presents a peak in the regions of (i) thermal neutrons ranged between 0.001 and 1 eV peaking at neutron energy ∼0.1 eV and (ii) fast neutrons ranged between 0.1 and 20 MeV peaking at neutron energy ∼1.2 MeV. The reduction of thermal neutrons is higher than the fast one as the distance from the reactor core increases since thermal neutrons capture by natural U-fuel has higher cross section than the fast neutrons.

Tilt assembly for tracking solar collector assembly

DOEpatents

Almy, Charles; Peurach, John; Sandler, Reuben

2012-01-24

A tilt assembly is used with a solar collector assembly of the type comprising a frame, supporting a solar collector, for movement about a tilt axis by pivoting a drive element between first and second orientations. The tilt assembly comprises a drive element coupler connected to the drive element and a driver, the driver comprising a drive frame, a drive arm and a drive arm driver. The drive arm is mounted to the drive frame for pivotal movement about a drive arm axis. Movement on the drive arm mimics movement of the drive element. Drive element couplers can extend in opposite directions from the outer portion of the drive arm, whereby the assembly can be used between adjacent solar collector assemblies in a row of solar collector assemblies.

Role of proton balance in formation of self-assembled chitosan nanoparticles.

PubMed

Dey, Anomitra; Kamat, Aditya; Nayak, Sonal; Danino, Dganit; Kesselman, Ellina; Dandekar, Prajakta; Jain, Ratnesh

2018-06-01

Researchers have explored the ability of chitosan to form nanoparticles, to suit varying applications, ranging from wound-healing to gene delivery. Ionic gelation is a widely used method for formulating chitosan nanoparticles, where self-assembly plays a crucial role. This self-assembly is initially promoted by hydrophilic-hydrophobic parity amongst individual chitosan residues, along with electrostatic and Van der Waals interactions with the cross-linker. However, until now the intrinsic ability of chitosan to self-assemble is not widely studied; hence, we investigate the self-assembly of chitosan, based on proton balance between its protonated and deprotonated residues, to promote facile nanoparticle synthesis. This is one of the first reports that highlights subtle but critical influence of proton balance in the chitosan polymer on the formation of chitosan nanoparticles. Copyright © 2018 Elsevier B.V. All rights reserved.

Framework for Defining and Assessing Benefits of a Modular Assembly Design Approach for Exploration Systems

NASA Technical Reports Server (NTRS)

Dorsey, John T.; Collins, Timothy J.; Moe, Rud V.; Doggett,. William R.

2006-01-01

A comprehensive modular assembly system model has been proposed that extends the art from modular hardware, to include in-space assembly, servicing and repair and it s critical components of infrastructure, agents and assembly operations. Benefits of modular assembly have been identified and a set of metrics defined that extends the art beyond the traditional measures of performance, with emphasis on criteria that allow life-cycle mission costs to be used as a figure of merit (and include all substantive terms that have an impact on the evaluation). The modular assembly approach was used as a basis for developing a Solar Electric Transfer Vehicle (SETV) concept and three modular assembly scenarios were developed. The modular assembly approach also allows the SETV to be entered into service much earlier than competing conventional configurations and results in a great deal of versatility in accommodating different launch vehicle payload capabilities, allowing for modules to be pre-assembled before launch or assembled on orbit, without changing the space vehicle design.

Engineering Globular Protein Vesicles through Tunable Self-Assembly of Recombinant Fusion Proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Yeongseon; Choi, Won Tae; Heller, William T.

Vesicles assembled from folded, globular proteins have potential for functions different from traditional lipid or polymeric vesicles. However, they also present challenges in understanding the assembly process and controlling vesicle properties. From detailed investigation of the assembly behavior of recombinant fusion proteins, this work reports a simple strategy to engineer protein vesicles containing functional, globular domains. This is achieved through tunable self-assembly of recombinant globular fusion proteins containing leucine zippers and elastin-like polypeptides. The fusion proteins form complexes in solution via high affinity binding of the zippers, and transition through dynamic coacervates to stable hollow vesicles upon warming. The thermalmore » driving force, which can be tuned by protein concentration or temperature, controls both vesicle size and whether vesicles are single or bi-layered. Lastly, these results provide critical information to engineer globular protein vesicles via self-assembly with desired size and membrane structure.« less

Engineering Globular Protein Vesicles through Tunable Self-Assembly of Recombinant Fusion Proteins

DOE PAGES

Jang, Yeongseon; Choi, Won Tae; Heller, William T.; ...

2017-07-27

Vesicles assembled from folded, globular proteins have potential for functions different from traditional lipid or polymeric vesicles. However, they also present challenges in understanding the assembly process and controlling vesicle properties. From detailed investigation of the assembly behavior of recombinant fusion proteins, this work reports a simple strategy to engineer protein vesicles containing functional, globular domains. This is achieved through tunable self-assembly of recombinant globular fusion proteins containing leucine zippers and elastin-like polypeptides. The fusion proteins form complexes in solution via high affinity binding of the zippers, and transition through dynamic coacervates to stable hollow vesicles upon warming. The thermalmore » driving force, which can be tuned by protein concentration or temperature, controls both vesicle size and whether vesicles are single or bi-layered. Lastly, these results provide critical information to engineer globular protein vesicles via self-assembly with desired size and membrane structure.« less

Evaluation of Cask Drop Criticality Issues at K Basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

GOLDMANN, L.H.

An analysis of ability of Multi-canister Overpack (MCO) to withstand drops at K Basin without exceeding the criticality design requirements. Report concludes the MCO will function acceptably. The spent fuel currently residing in the 105 KE and 105 KW storage basins will be placed in fuel storage baskets which will be loaded into the MCO cask assembly. During the basket loading operations the MCO cask assembly will be positioned near the bottom of the south load out pit (SLOP). The loaded MCO cask will be lifted from the SLOP transferred to the transport trailer and delivered to the Cold Vacuummore » Drying Facility (CVDF). In the wet condition there is a potential for criticality problems if significant changes in the designed fuel configurations occur. The purpose of this report is to address structural issues associated with criticality design features for MCO cask drop accidents in the 105 KE and 105 KW facilities.« less

An Approach to Self-Assembling Swarm Robots Using Multitree Genetic Programming

PubMed Central

An, Jinung

2013-01-01

In recent days, self-assembling swarm robots have been studied by a number of researchers due to their advantages such as high efficiency, stability, and scalability. However, there are still critical issues in applying them to practical problems in the real world. The main objective of this study is to develop a novel self-assembling swarm robot algorithm that overcomes the limitations of existing approaches. To this end, multitree genetic programming is newly designed to efficiently discover a set of patterns necessary to carry out the mission of the self-assembling swarm robots. The obtained patterns are then incorporated into their corresponding robot modules. The computational experiments prove the effectiveness of the proposed approach. PMID:23861655

An approach to self-assembling swarm robots using multitree genetic programming.

PubMed

Lee, Jong-Hyun; Ahn, Chang Wook; An, Jinung

2013-01-01

In recent days, self-assembling swarm robots have been studied by a number of researchers due to their advantages such as high efficiency, stability, and scalability. However, there are still critical issues in applying them to practical problems in the real world. The main objective of this study is to develop a novel self-assembling swarm robot algorithm that overcomes the limitations of existing approaches. To this end, multitree genetic programming is newly designed to efficiently discover a set of patterns necessary to carry out the mission of the self-assembling swarm robots. The obtained patterns are then incorporated into their corresponding robot modules. The computational experiments prove the effectiveness of the proposed approach.

Los Alamos Shows Airport Security Technology at Work

ScienceCinema

Espy, Michelle; Schultz, Larry; Hunter, James

2018-05-30

Los Alamos scientists have advanced a Magnetic Resonance Imaging (MRI) technology that may provide a breakthrough for screening liquids at airport security. They've added low-power X-ray data to the mix, and as a result have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new system is named MagRay. The goal is to quickly and accurately distinguish between liquids that visually appear identical. For example, what appears to be a bottle of white wine could potentially be nitromethane, a liquid that could be used to make an explosive. Both are clear liquids, one would be perfectly safe on a commercial aircraft, the other would be strictly prohibited. How to tell them apart quickly without error at an airport security area is the focus of Michelle Espy, Larry Schultz and their team. In this video, Espy and the MagRay team explain how the new technology works, how they've developed an easy operator interface, and what the next steps might be in transitioning this technology to the private sector.

World's Largest Gold Crystal Studied at Los Alamos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vogel, Sven; Nakotte, Heinz

2014-04-03

When geologist John Rakovan needed better tools to investigate whether a dazzling 217.78-gram piece of gold was in fact the world's largest single-crystal specimen - a distinguishing factor that would not only drastically increase its market value but also provide a unique research opportunity - he traveled to Los Alamos National Laboratory's Lujan Neutron Scattering Center to peer deep inside the mineral using neutron diffractometry. Neutrons, different from other probes such as X-rays and electrons, are able to penetrate many centimeters deep into most materials. Revealing the inner structure of a crystal without destroying the sample - imperative, as thismore » one is worth an estimated $1.5 million - would allow Rakovan and Lujan Center collaborators Sven Vogel and Heinz Nakotte to prove that this exquisite nugget, which seemed almost too perfect and too big to be real, was a single crystal and hence a creation of nature. Its owner, who lives in the United States, provided the samples to Rakovan to assess the crystallinity of four specimens, all of which had been found decades ago in Venezuela.« less

World's Largest Gold Crystal Studied at Los Alamos

ScienceCinema

Vogel, Sven; Nakotte, Heinz

2018-02-07

When geologist John Rakovan needed better tools to investigate whether a dazzling 217.78-gram piece of gold was in fact the world's largest single-crystal specimen - a distinguishing factor that would not only drastically increase its market value but also provide a unique research opportunity - he traveled to Los Alamos National Laboratory's Lujan Neutron Scattering Center to peer deep inside the mineral using neutron diffractometry. Neutrons, different from other probes such as X-rays and electrons, are able to penetrate many centimeters deep into most materials. Revealing the inner structure of a crystal without destroying the sample - imperative, as this one is worth an estimated $1.5 million - would allow Rakovan and Lujan Center collaborators Sven Vogel and Heinz Nakotte to prove that this exquisite nugget, which seemed almost too perfect and too big to be real, was a single crystal and hence a creation of nature. Its owner, who lives in the United States, provided the samples to Rakovan to assess the crystallinity of four specimens, all of which had been found decades ago in Venezuela.

Interconnect assembly for an electronic assembly and assembly method therefor

DOEpatents

Gerbsch, Erich William

2003-06-10

An interconnect assembly and method for a semiconductor device, in which the interconnect assembly can be used in lieu of wirebond connections to form an electronic assembly. The interconnect assembly includes first and second interconnect members. The first interconnect member has a first surface with a first contact and a second surface with a second contact electrically connected to the first contact, while the second interconnect member has a flexible finger contacting the second contact of the first interconnect member. The first interconnect member is adapted to be aligned and registered with a semiconductor device having a contact on a first surface thereof, so that the first contact of the first interconnect member electrically contacts the contact of the semiconductor device. Consequently, the assembly method does not require any wirebonds, but instead merely entails aligning and registering the first interconnect member with the semiconductor device so that the contacts of the first interconnect member and the semiconductor device make electrically contact, and then contacting the second contact of the first interconnect member with the flexible finger of the second interconnect member.

Multidimensional analysis of fast-spectrum material replacement measurements for systematic estimation of cross section uncertainties

NASA Technical Reports Server (NTRS)

Klann, P. G.; Lantz, E.; Mayo, W. T.

1973-01-01

A series of central core and core-reflector interface sample replacement experiments for 16 materials performed in the NASA heavy-metal-reflected, fast spectrum critical assembly (NCA) were analyzed in four and 13 groups using the GAM 2 cross-section set. The individual worths obtained by TDSN and DOT multidimensional transport theory calculations showed significant differences from the experimental results. These were attributed to cross-section uncertainties in the GAM 2 cross sections. Simultaneous analysis of the measured and calculated sample worths permitted separation of the worths into capture and scattering components which systematically provided fast spectrum averaged correction factors to the magnitudes of the GAM 2 absorption and scattering cross sections. Several Los Alamos clean critical assemblies containing Oy, Ta, and Mo as well as one of the NCA compositions were reanalyzed using the corrected cross sections. In all cases the eigenvalues were significantly improved and were recomputed to within 1 percent of the experimental eigenvalue. A comparable procedure may be used for ENDF cross sections when these are available.

Data Mining Techniques to Estimate Plutonium, Initial Enrichment, Burnup, and Cooling Time in Spent Fuel Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trellue, Holly Renee; Fugate, Michael Lynn; Tobin, Stephen Joesph

The Next Generation Safeguards Initiative (NGSI), Office of Nonproliferation and Arms Control (NPAC), National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE) has sponsored a multi-laboratory, university, international partner collaboration to (1) detect replaced or missing pins from spent fuel assemblies (SFA) to confirm item integrity and deter diversion, (2) determine plutonium mass and related plutonium and uranium fissile mass parameters in SFAs, and (3) verify initial enrichment (IE), burnup (BU), and cooling time (CT) of facility declaration for SFAs. A wide variety of nondestructive assay (NDA) techniques were researched to achieve these goals [Veal, 2010 andmore » Humphrey, 2012]. In addition, the project includes two related activities with facility-specific benefits: (1) determination of heat content and (2) determination of reactivity (multiplication). In this research, a subset of 11 integrated NDA techniques was researched using data mining solutions at Los Alamos National Laboratory (LANL) for their ability to achieve the above goals.« less

Fast assembly of ordered block copolymer nanostructures through microwave annealing.

PubMed

Zhang, Xiaojiang; Harris, Kenneth D; Wu, Nathanael L Y; Murphy, Jeffrey N; Buriak, Jillian M

2010-11-23

Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy.

Molecular Origins of Thermal Transitions in Polyelectrolyte Assemblies

NASA Astrophysics Data System (ADS)

Yildirim, Erol; Zhang, Yanpu; Antila, Hanne S.; Lutkenhaus, Jodie L.; Sammalkorpi, Maria; Aalto Team; Texas A&M Team

2015-03-01

Polyelectrolyte (PE) multilayers and complexes formed from oppositely charged polymers can exhibit extraordinary superhydrophobicity, mechanical strength and responsiveness resulting in applications ranging functional membranes, optics, sensors and drug delivery. Depending on the assembly conditions, PE assemblies may undergo a thermal transition from glassy to soft behavior under heating. Our earlier work using thermal analysis measurements shows a distinct thermal transition for PE layer-by-layer (LbL) systems assembled with added salt but no analogous transition in films assembled without added salt or dry systems. These findings raise interesting questions on the nature of the thermal transition; here, we explore its molecular origins through characterization of the PE aggregates by temperature-controlled all-atom molecular dynamics simulations. We show via molecular simulations the thermal transition results from the existence of an LCST (lower critical solution temperature) in the PE systems: the diffusion behavior, hydrogen bond formation, and bridging capacity of water molecules plasticizing the complex changes at the transition temperature. We quantify the behavior, map its chemistry specificity through comparison of strongly and weakly charged PE complexes, and connect the findings to our interrelated QCM-D experiments.

ZPPR-20 phase D : a cylindrical assembly of polyethylene moderated U metal reflected by beryllium oxide and polyethylene.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lell, R.; Grimm, K.; McKnight, R.

The Zero Power Physics Reactor (ZPPR) fast critical facility was built at the Argonne National Laboratory-West (ANL-W) site in Idaho in 1969 to obtain neutron physics information necessary for the design of fast breeder reactors. The ZPPR-20D Benchmark Assembly was part of a series of cores built in Assembly 20 (References 1 through 3) of the ZPPR facility to provide data for developing a nuclear power source for space applications (SP-100). The assemblies were beryllium oxide reflected and had core fuel compositions containing enriched uranium fuel, niobium and rhenium. ZPPR-20 Phase C (HEU-MET-FAST-075) was built as the reference flight configuration.more » Two other configurations, Phases D and E, simulated accident scenarios. Phase D modeled the water immersion scenario during a launch accident, and Phase E (SUB-HEU-MET-FAST-001) modeled the earth burial scenario during a launch accident. Two configurations were recorded for the simulated water immersion accident scenario (Phase D); the critical configuration, documented here, and the subcritical configuration (SUB-HEU-MET-MIXED-001). Experiments in Assembly 20 Phases 20A through 20F were performed in 1988. The reference water immersion configuration for the ZPPR-20D assembly was obtained as reactor loading 129 on October 7, 1988 with a fissile mass of 167.477 kg and a reactivity of -4.626 {+-} 0.044{cents} (k {approx} 0.9997). The SP-100 core was to be constructed of highly enriched uranium nitride, niobium, rhenium and depleted lithium. The core design called for two enrichment zones with niobium-1% zirconium alloy fuel cladding and core structure. Rhenium was to be used as a fuel pin liner to provide shut down in the event of water immersion and flooding. The core coolant was to be depleted lithium metal ({sup 7}Li). The core was to be surrounded radially with a niobium reactor vessel and bypass which would carry the lithium coolant to the forward inlet plenum. Immediately inside the reactor vessel was a

Orientation-controlled parallel assembly at the air-water interface

NASA Astrophysics Data System (ADS)

Park, Kwang Soon; Hao Hoo, Ji; Baskaran, Rajashree; Böhringer, Karl F.

2012-10-01

This paper presents an experimental and theoretical study with statistical analysis of a high-yield, orientation-specific fluidic self-assembly process on a preprogrammed template. We demonstrate self-assembly of thin (less than few hundred microns in thickness) parts, which is vital for many applications in miniaturized platforms but problematic for today's pick-and-place robots. The assembly proceeds row-by-row as the substrate is pulled up through an air-water interface. Experiments and analysis are presented with an emphasis on the combined effect of controlled surface waves and magnetic force. For various gap values between a magnet and Ni-patterned parts, magnetic force distributions are generated using Monte Carlo simulation and employed to predict assembly yield. An analysis of these distributions shows that a gradual decline in yield following the probability density function can be expected with degrading conditions. The experimentally determined critical magnetic force is in good agreement with a derived value from a model of competing forces acting on a part. A general set of design guidelines is also presented from the developed model and experimental data.

Structural insight into TPX2-stimulated microtubule assembly

PubMed Central

2017-01-01

During mitosis and meiosis, microtubule (MT) assembly is locally upregulated by the chromatin-dependent Ran-GTP pathway. One of its key targets is the MT-associated spindle assembly factor TPX2. The molecular mechanism of how TPX2 stimulates MT assembly remains unknown because structural information about the interaction of TPX2 with MTs is lacking. Here, we determine the cryo-electron microscopy structure of a central region of TPX2 bound to the MT surface. TPX2 uses two flexibly linked elements (’ridge’ and ‘wedge’) in a novel interaction mode to simultaneously bind across longitudinal and lateral tubulin interfaces. These MT-interacting elements overlap with the binding site of importins on TPX2. Fluorescence microscopy-based in vitro reconstitution assays reveal that this interaction mode is critical for MT binding and facilitates MT nucleation. Together, our results suggest a molecular mechanism of how the Ran-GTP gradient can regulate TPX2-dependent MT formation. PMID:29120325

The microviridae: Diversity, assembly, and experimental evolution.

PubMed

Doore, Sarah M; Fane, Bentley A

2016-04-01

The Microviridae, comprised of ssDNA, icosahedral bacteriophages, are a model system for studying morphogenesis and the evolution of assembly. Historically limited to the φX174-like viruses, recent results demonstrate that this richly diverse family is broadly divided into two groups. The defining feature appears to be whether one or two scaffolding proteins are required for assembly. The single-scaffolding systems contain an internal scaffolding protein, similar to many dsDNA viruses, and have a more complex coat protein fold. The two-scaffolding protein systems (φX174-like) encode an internal and external species, as well as an additional structural protein: a spike on the icosahedral vertices. Here, we discuss recent in silico and in vivo evolutionary analyses conducted with chimeric viruses and/or chimeric proteins. The results suggest 1) how double scaffolding systems can evolve into single and triple scaffolding systems; and 2) how assembly is the critical factor governing adaptation and the maintenance of species boundaries. Copyright © 2016 Elsevier Inc. All rights reserved.

Regulation of corneal stroma extracellular matrix assembly.

PubMed

Chen, Shoujun; Mienaltowski, Michael J; Birk, David E

2015-04-01

The transparent cornea is the major refractive element of the eye. A finely controlled assembly of the stromal extracellular matrix is critical to corneal function, as well as in establishing the appropriate mechanical stability required to maintain corneal shape and curvature. In the stroma, homogeneous, small diameter collagen fibrils, regularly packed with a highly ordered hierarchical organization, are essential for function. This review focuses on corneal stroma assembly and the regulation of collagen fibrillogenesis. Corneal collagen fibrillogenesis involves multiple molecules interacting in sequential steps, as well as interactions between keratocytes and stroma matrix components. The stroma has the highest collagen V:I ratio in the body. Collagen V regulates the nucleation of protofibril assembly, thus controlling the number of fibrils and assembly of smaller diameter fibrils in the stroma. The corneal stroma is also enriched in small leucine-rich proteoglycans (SLRPs) that cooperate in a temporal and spatial manner to regulate linear and lateral collagen fibril growth. In addition, the fibril-associated collagens (FACITs) such as collagen XII and collagen XIV have roles in the regulation of fibril packing and inter-lamellar interactions. A communicating keratocyte network contributes to the overall and long-range regulation of stromal extracellular matrix assembly, by creating micro-domains where the sequential steps in stromal matrix assembly are controlled. Keratocytes control the synthesis of extracellular matrix components, which interact with the keratocytes dynamically to coordinate the regulatory steps into a cohesive process. Mutations or deficiencies in stromal regulatory molecules result in altered interactions and deficiencies in both transparency and refraction, leading to corneal stroma pathobiology such as stromal dystrophies, cornea plana and keratoconus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Regulation of Corneal Stroma Extracellular Matrix Assembly

PubMed Central

Chen, Shoujun; Mienaltowski, Michael J.; Birk, David E.

2014-01-01

The transparent cornea is the major refractive element of the eye. A finely controlled assembly of the stromal extracellular matrix is critical to corneal function, as well as in establishing the appropriate mechanical stability required to maintain corneal shape and curvature. In the stroma, homogeneous, small diameter collagen fibrils, regularly packed with a highly ordered hierarchical organization, are essential for function. This review focuses on corneal stroma assembly and the regulation of collagen fibrillogenesis. Corneal collagen fibrillogenesis involves multiple molecules interacting in sequential steps, as well as interactions between keratocytes and stroma matrix components. The stroma has the highest collagen V:I ratio in the body. Collagen V regulates the nucleation of protofibril assembly, thus controlling the number of fibrils and assembly of smaller diameter fibrils in the stroma. The corneal stroma is also enriched in small leucine-rich proteoglycans (SLRPs) that cooperate in a temporal and spatial manner to regulate linear and lateral collagen fibril growth. In addition, the fibril-associated collagens (FACITs) such as collagen XII and collagen XIV have roles in the regulation of fibril packing and inter-lamellar interactions. A communicating keratocyte network contributes to the overall and long-range regulation of stromal extracellular matrix assembly, by creating micro-domains where the sequential steps in stromal matrix assembly are controlled. Keratocytes control the synthesis of extracellular matrix components, which interact with the keratocytes dynamically to coordinate the regulatory steps into a cohesive process. Mutations or deficiencies in stromal regulatory molecules result in altered interactions and deficiencies in both transparency and refraction, leading to corneal stroma pathobiology such as stromal dystrophies, cornea plana and keratoconus. PMID:25819456

40 CFR 1033.630 - Staged-assembly and delegated assembly exemptions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Staged-assembly and delegated assembly... Staged-assembly and delegated assembly exemptions. (a) Staged assembly. You may ask us to provide a... assembly. This paragraph (b) applies where the engine manufacturer/remanufacturer does not complete...

40 CFR 1033.630 - Staged-assembly and delegated assembly exemptions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Staged-assembly and delegated assembly... Staged-assembly and delegated assembly exemptions. (a) Staged assembly. You may ask us to provide a... assembly. This paragraph (b) applies where the engine manufacturer/remanufacturer does not complete...

40 CFR 1033.630 - Staged-assembly and delegated assembly exemptions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Staged-assembly and delegated assembly... Staged-assembly and delegated assembly exemptions. (a) Staged assembly. You may ask us to provide a... assembly. This paragraph (b) applies where the engine manufacturer/remanufacturer does not complete...

40 CFR 1033.630 - Staged-assembly and delegated assembly exemptions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Staged-assembly and delegated assembly... Staged-assembly and delegated assembly exemptions. (a) Staged assembly. You may ask us to provide a... assembly. This paragraph (b) applies where the engine manufacturer/remanufacturer does not complete...

Assembly constraints drive co-evolution among ribosomal constituents.

PubMed

Mallik, Saurav; Akashi, Hiroshi; Kundu, Sudip

2015-06-23

Ribosome biogenesis, a central and essential cellular process, occurs through sequential association and mutual co-folding of protein-RNA constituents in a well-defined assembly pathway. Here, we construct a network of co-evolving nucleotide/amino acid residues within the ribosome and demonstrate that assembly constraints are strong predictors of co-evolutionary patterns. Predictors of co-evolution include a wide spectrum of structural reconstitution events, such as cooperativity phenomenon, protein-induced rRNA reconstitutions, molecular packing of different rRNA domains, protein-rRNA recognition, etc. A correlation between folding rate of small globular proteins and their topological features is known. We have introduced an analogous topological characteristic for co-evolutionary network of ribosome, which allows us to differentiate between rRNA regions subjected to rapid reconstitutions from those hindered by kinetic traps. Furthermore, co-evolutionary patterns provide a biological basis for deleterious mutation sites and further allow prediction of potential antibiotic targeting sites. Understanding assembly pathways of multicomponent macromolecules remains a key challenge in biophysics. Our study provides a 'proof of concept' that directly relates co-evolution to biophysical interactions during multicomponent assembly and suggests predictive power to identify candidates for critical functional interactions as well as for assembly-blocking antibiotic target sites. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

ZPR-6 assembly 7 high {sup 240} PU core : a cylindrical assemby with mixed (PU, U)-oxide fuel and a central high {sup 240} PU zone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lell, R. M.; Schaefer, R. W.; McKnight, R. D.

Over a period of 30 years more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited to form the basis for criticality safety benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactormore » physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. The term 'benchmark' in a ZPR program connotes a particularly simple loading aimed at gaining basic reactor physics insight, as opposed to studying a reactor design. In fact, the ZPR-6/7 Benchmark Assembly (Reference 1) had a very simple core unit cell assembled from plates of depleted uranium, sodium, iron oxide, U3O8, and plutonium. The ZPR-6/7 core cell-average composition is typical of the interior region of liquid-metal fast breeder reactors (LMFBRs) of the era. It was one part of the Demonstration Reactor Benchmark Program,a which provided integral experiments characterizing the important features of

30 CFR 7.405 - Critical characteristics.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cable Splice Kits § 7.405 Critical characteristics. (a) A sample from each production run, batch, or lot of manufactured electric cable, signaling cable, or splice made from a splice kit shall be flame... cable or splice and a sample of the cable or splice kit assembly shall be visually inspected or tested...

30 CFR 7.405 - Critical characteristics.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Cable Splice Kits § 7.405 Critical characteristics. (a) A sample from each production run, batch, or lot of manufactured electric cable, signaling cable, or splice made from a splice kit shall be flame... cable or splice and a sample of the cable or splice kit assembly shall be visually inspected or tested...

The assembly of MreB, a prokaryotic homolog of actin.

PubMed

Esue, Osigwe; Cordero, Maria; Wirtz, Denis; Tseng, Yiider

2005-01-28

MreB, a major component of the bacterial cytoskeleton, exhibits high structural homology to its eukaryotic counterpart actin. Live cell microscopy studies suggest that MreB molecules organize into large filamentous spirals that support the cell membrane and play a key shape-determining function. However, the basic properties of MreB filament assembly remain unknown. Here, we studied the assembly of Thermotoga maritima MreB triggered by ATP in vitro and compared it to the well-studied assembly of actin. These studies show that MreB filament ultrastructure and polymerization depend crucially on temperature as well as the ions present on solution. At the optimal growth temperature of T. maritima, MreB assembly proceeded much faster than that of actin, without nucleation (or nucleation is highly favorable and fast) and with little or no contribution from filament end-to-end annealing. MreB exhibited rates of ATP hydrolysis and phosphate release similar to that of F-actin, however, with a critical concentration of approximately 3 nm, which is approximately 100-fold lower than that of actin. Furthermore, MreB assembled into filamentous bundles that have the ability to spontaneously form ring-like structures without auxiliary proteins. These findings suggest that despite high structural homology, MreB and actin display significantly different assembly properties.

Transportation of part supply improvement in agricultural machinery assembly plant

NASA Astrophysics Data System (ADS)

Saysaman, Anusit; Chutima, Parames

2018-02-01

This research focused on the problem caused by the transportation of part supply in agricultural machinery assembly plant in Thailand, which is one of the processes that are critical to the whole production process. If poorly managed, it will affect transportation of part supply, the emergence of sink cost, quality problems, and the ability to respond to the needs of the customers in time. Since the competition in the agricultural machinery market is more intense, the efficiency of part transportation process has to be improved. In this study, the process of transporting parts of the plant was studied and it was found that the efficiency of the process of transporting parts from the sub assembly line to its main assembly line was 83%. The approach to the performance improvement is done by using the Lean tool to limit wastes based on the ECRS principle and applying pull production system by changing the transportation method to operate as milkrun for transportation of parts to synchronize with the part demands of the main assembly line. After the transportation of parts from sub-assembly line to the main assembly line was improved, the efficiency raised to 98% and transportation process cost was saved to 540,000 Baht per year.

Environmental surveillance at Los Alamos during 1991. Environmental protection group

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewart, J.; Kohen, K.L.

1993-08-01

This report describes the environmental surveillance program conducted by Los Alamos National Laboratory during 1991. Routine monitoring for radiation and for radioactive and chemical materials is conducted on the Laboratory site as well as in the surrounding region. Monitoring results are used to determine compliance with appropriate standards and to permit early identification of potentially undesirable trends. Results and interpretation of data for 1991 cover external penetrating radiation; quantities of airborne emissions and effluents; concentrations of chemicals and radionuclides in ambient air, surface waters and groundwaters, municipal water supply, soils and sediments, and foodstuffs; and environmental compliance. Comparisons with appropriatemore » standards, regulations, and background levels provide the basis for concluding that environmental effects from Laboratory operations are small and do not pose a threat to the public, Laboratory employees, or the environment.« less

Monitoring Sensitive Bat Species at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schoenberg, Kari M.

Bats play a critical role in ecosystems and are vulnerable to disturbance and disruption by human activities. In recent decades, bat populations in the United States and elsewhere have decreased tremendously. There are 47 different species of bat in the United States and 28 of these occur in New Mexico with 15 different species documented at the Los Alamos National Laboratory (LANL) and surrounding areas. Euderma maculatum(the spotted bat) is listed as “threatened” by the state of New Mexico and is known to occur at LANL. Four other species of bats are listed as “sensitive” and also occur here. Inmore » 1995, a four year study was initiated at LANL to assess the status of bat species of concern, elucidate distribution and relative abundance, and obtain information on roosting sites. There have been no definitive studies since then. Biologists in the Environmental Protection Division at LANL initiated a multi-year monitoring program for bats in May 2013 to implement the Biological Resources Management Plan. The objective of this ongoing study is to monitor bat species diversity and seasonal activity over time at LANL. Bat species diversity and seasonal activity were measured using an acoustic bat detector, the Pettersson D500X. This ultrasound recording unit is intended for long-term, unattended recording of bat and other high frequency animal calls. During 2013, the detector was deployed at two locations around LANL. Study sites were selected based on proximity to water where bats may be foraging. Recorded bat calls were analyzed using Sonobat, software that can help determine specific species of bat through their calls. A list of bat species at the two sites was developed and compared to lists from previous studies. Species diversity and seasonal activity, measured as the number of call sequences recorded each month, were compared between sites and among months. A total of 17,923 bat calls were recorded representing 15 species. Results indicate that

2010 Community College Futures Assembly Focus: Effective Leadership-Addressing the Graduation Challenge in the 21st Century

ERIC Educational Resources Information Center

Campbell, Dale F.; Yu, Hongwei

2010-01-01

The Community College Futures Assembly has served as a national independent policy think tank since 1995. Its purpose is to articulate the critical issues facing American community colleges and recognize innovative programs. Convening annually in January in Orlando, Florida, the Assembly provides an interactive learning environment where tough…

Rewriting nature's assembly manual for a ssRNA virus.

PubMed

Patel, Nikesh; Wroblewski, Emma; Leonov, German; Phillips, Simon E V; Tuma, Roman; Twarock, Reidun; Stockley, Peter G

2017-11-14

Satellite tobacco necrosis virus (STNV) is one of the smallest viruses known. Its genome encodes only its coat protein (CP) subunit, relying on the polymerase of its helper virus TNV for replication. The genome has been shown to contain a cryptic set of dispersed assembly signals in the form of stem-loops that each present a minimal CP-binding motif AXXA in the loops. The genomic fragment encompassing nucleotides 1-127 is predicted to contain five such packaging signals (PSs). We have used mutagenesis to determine the critical assembly features in this region. These include the CP-binding motif, the relative placement of PS stem-loops, their number, and their folding propensity. CP binding has an electrostatic contribution, but assembly nucleation is dominated by the recognition of the folded PSs in the RNA fragment. Mutation to remove all AXXA motifs in PSs throughout the genome yields an RNA that is unable to assemble efficiently. In contrast, when a synthetic 127-nt fragment encompassing improved PSs is swapped onto the RNA otherwise lacking CP recognition motifs, assembly is partially restored, although the virus-like particles created are incomplete, implying that PSs outside this region are required for correct assembly. Swapping this improved region into the wild-type STNV1 sequence results in a better assembly substrate than the viral RNA, producing complete capsids and outcompeting the wild-type genome in head-to-head competition. These data confirm details of the PS-mediated assembly mechanism for STNV and identify an efficient approach for production of stable virus-like particles encapsidating nonnative RNAs or other cargoes. Copyright © 2017 the Author(s). Published by PNAS.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Venkateswaran, Kasthuri J.; Vaishampayan, Parag A.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 mRad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 Mrad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

An Assembly Funnel Makes Biomolecular Complex Assembly Efficient

PubMed Central

Zenk, John; Schulman, Rebecca

2014-01-01

Like protein folding and crystallization, the self-assembly of complexes is a fundamental form of biomolecular organization. While the number of methods for creating synthetic complexes is growing rapidly, most require empirical tuning of assembly conditions and/or produce low yields. We use coarse-grained simulations of the assembly kinetics of complexes to identify generic limitations on yields that arise because of the many simultaneous interactions allowed between the components and intermediates of a complex. Efficient assembly occurs when nucleation is fast and growth pathways are few, i.e. when there is an assembly “funnel”. For typical complexes, an assembly funnel occurs in a narrow window of conditions whose location is highly complex specific. However, by redesigning the components this window can be drastically broadened, so that complexes can form quickly across many conditions. The generality of this approach suggests assembly funnel design as a foundational strategy for robust biomolecular complex synthesis. PMID:25360818

Recent Research with the Detector for Advanced Neutron Capture Experiments (dance) at the LOS Alamos Neutron Science Center

NASA Astrophysics Data System (ADS)

Ullmann, J. L.

2014-09-01

The DANCE detector at Los Alamos is a 160 element, nearly 4π BaF2 detector array designed to make measurements of neutron capture on rare or radioactive nuclides. It has also been used to make measurements of gamma-ray multiplicity following capture and gamma-ray output from fission. Several examples of measurements are briefly discussed.

The Los Alamos Laser Acceleration of Particles Workshop and beginning of the advanced accelerator concepts field

NASA Astrophysics Data System (ADS)

Joshi, C.

2012-12-01

The first Advanced Acceleration of Particles-AAC-Workshop (actually named Laser Acceleration of Particles Workshop) was held at Los Alamos in January 1982. The workshop lasted a week and divided all the acceleration techniques into four categories: near field, far field, media, and vacuum. Basic theorems of particle acceleration were postulated (later proven) and specific experiments based on the four categories were formulated. This landmark workshop led to the formation of the advanced accelerator R&D program in the HEP office of the DOE that supports advanced accelerator research to this day. Two major new user facilities at Argonne and Brookhaven and several more directed experimental efforts were built to explore the advanced particle acceleration schemes. It is not an exaggeration to say that the intellectual breadth and excitement provided by the many groups who entered this new field provided the needed vitality to then recently formed APS Division of Beams and the new online journal Physical Review Special Topics-Accelerators and Beams. On this 30th anniversary of the AAC Workshops, it is worthwhile to look back at the legacy of the first Workshop at Los Alamos and the fine groundwork it laid for the field of advanced accelerator concepts that continues to flourish to this day.

Capabilities for high explosive pulsed power research at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goforth, James H; Oona, Henn; Tasker, Douglas G

2008-01-01

Research on topics requiring high magnetic fields and high currents have been pursued using high explosive pulsed power (HEPP) techniques since the 1950s at Los Alamos National Laboratory. We have developed many sophisticated HEPr systems through the years, and most of them depend on technology available from the nuclear weapons program. Through the 1980s and 1990s, our budgets would sustain parallel efforts in zpinch research using both HEPr and capacitor banks. In recent years, many changes have occurred that are driven by concerns such as safety, security, and environment, as well as reduced budgets and downsizing of the National Nuclearmore » Security Administration (NNSA) complex due to the end of the cold war era. In this paper, we review the teclmiques developed to date, and adaptations that are driven by changes in budgets and our changing complex. One new Ranchero-based solid liner z-pinch experimental design is also presented. Explosives that are cast to shape instead of being machined, and initiation systems that depend on arrays of slapper detonators are important new tools. Some materials that are seen as hazardous to the environment are avoided in designs. The process continues to allow a wide range of research however, and there are few, if any, experiments that we have done in the past that could not be perform today. The HErr firing facility at Los Alamos continues to have a 2000 lb. high explosive limit, and our 2.4 MJ capacitor bank remains a mainstay of the effort. Modem diagnostic and data analysis capabilities allow fewer personnel to achieve better results, and in the broad sense we continue to have a robust capability.« less

Detection of Intermediates And Kinetic Control During Assembly of Bacteriophage P22 Procapsid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuma, R.; Tsuruta, H.; French, K.H.

2009-05-26

Bacteriophage P22 serves as a model for the assembly and maturation of other icosahedral double-stranded DNA viruses. P22 coat and scaffolding proteins assemble in vitro into an icosahedral procapsid, which then expands during DNA packaging (maturation). Efficient in vitro assembly makes this system suitable for design and production of monodisperse spherical nanoparticles (diameter {approx} 50 nm). In this work, we explore the possibility of controlling the outcome of assembly by scaffolding protein engineering. The scaffolding protein exists in monomer-dimer-tetramer equilibrium. We address the role of monomers and dimers in assembly by using three different scaffolding proteins with altered monomer-dimer equilibriummore » (weak dimer, covalent dimer, monomer). The progress and outcome of assembly was monitored by time-resolved X-ray scattering, which allowed us to distinguish between closed shells and incomplete assembly intermediates. Binding of scaffolding monomer activates the coat protein for assembly. Excess dimeric scaffolding protein resulted in rapid nucleation and kinetic trapping yielding incomplete shells. Addition of monomeric wild-type scaffold with excess coat protein completed these metastable shells. Thus, the monomeric scaffolding protein plays an essential role in the elongation phase by activating the coat and effectively lowering its critical concentration for assembly.« less

Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

NASA Technical Reports Server (NTRS)

Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

2017-01-01

This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called digital materials. We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

Robotically Assembled Aerospace Structures: Digital Material Assembly using a Gantry-Type Assembler

NASA Technical Reports Server (NTRS)

Trinh, Greenfield; Copplestone, Grace; O'Connor, Molly; Hu, Steven; Nowak, Sebastian; Cheung, Kenneth; Jenett, Benjamin; Cellucci, Daniel

2017-01-01

This paper evaluates the development of automated assembly techniques for discrete lattice structures using a multi-axis gantry type CNC machine. These lattices are made of discrete components called "digital materials." We present the development of a specialized end effector that works in conjunction with the CNC machine to assemble these lattices. With this configuration we are able to place voxels at a rate of 1.5 per minute. The scalability of digital material structures due to the incremental modular assembly is one of its key traits and an important metric of interest. We investigate the build times of a 5x5 beam structure on the scale of 1 meter (325 parts), 10 meters (3,250 parts), and 30 meters (9,750 parts). Utilizing the current configuration with a single end effector, performing serial assembly with a globally fixed feed station at the edge of the build volume, the build time increases according to a scaling law of n4, where n is the build scale. Build times can be reduced significantly by integrating feed systems into the gantry itself, resulting in a scaling law of n3. A completely serial assembly process will encounter time limitations as build scale increases. Automated assembly for digital materials can assemble high performance structures from discrete parts, and techniques such as built in feed systems, parallelization, and optimization of the fastening process will yield much higher throughput.

Analysis of large space structures assembly: Man/machine assembly analysis

NASA Technical Reports Server (NTRS)

1983-01-01

Procedures for analyzing large space structures assembly via three primary modes: manual, remote and automated are outlined. Data bases on each of the assembly modes and a general data base on the shuttle capabilities to support structures assembly are presented. Task element times and structure assembly component costs are given to provide a basis for determining the comparative economics of assembly alternatives. The lessons learned from simulations of space structures assembly are detailed.

Electron cryo-microscopy structure of Ebola nucleoprotein reveals a mechanism for nucleocapsid-like assembly

PubMed Central

Su, Zhaoming; Wu, Chao; Shi, Liuqing; Luthra, Priya; Pintilie, Grigore D.; Johnson, Britney; Porter, Justin R.; Ge, Peng; Chen, Muyuan; Liu, Gai; Frederick, Thomas E.; Binning, Jennifer M.; Bowman, Gregory R.; Zhou, Z. Hong; Basler, Christopher F.; Gross, Michael L.; Leung, Daisy W.

2018-01-01

Summary Ebola virus nucleoprotein (eNP) assembles into higher-ordered structures that form the viral nucleocapsid (NC) and serve as the scaffold for viral RNA synthesis. However, molecular insights into the NC assembly process are lacking. Using a hybrid approach, we characterized the NC-like assembly of eNP, identified novel regulatory elements, and described how these elements impact function. We generated a three-dimensional structure of the eNP NC-like assembly at 5.8 Å using electron cryo-microscopy and identified a new regulatory role for eNP helices α22–α23. Biochemical, biophysical, and mutational analysis revealed inter-eNP contacts within α22–α23 are critical for viral NC-assembly and regulate viral RNA synthesis. These observations suggest that the N-terminus and α22–α23 of eNP function as context dependent regulatory modules (CDRMs). Our current study provides a framework for a structural mechanism for NC-like assembly and a new therapeutic target. PMID:29474922

Consistent criticality and radiation studies of Swiss spent nuclear fuel: The CS2M approach.

PubMed

Rochman, D; Vasiliev, A; Ferroukhi, H; Pecchia, M

2018-06-15

In this paper, a new method is proposed to systematically calculate at the same time canister loading curves and radiation sources, based on the inventory information from an in-core fuel management system. As a demonstration, the isotopic contents of the assemblies come from a Swiss PWR, considering more than 6000 cases from 34 reactor cycles. The CS 2 M approach consists in combining four codes: CASMO and SIMULATE to extract the assembly characteristics (based on validated models), the SNF code for source emission and MCNP for criticality calculations for specific canister loadings. The considered cases cover enrichments from 1.9 to 5.0% for the UO 2 assemblies and 4.8% for the MOX, with assembly burnup values from 7 to 74 MWd/kgU. Because such a study is based on the individual fuel assembly history, it opens the possibility to optimize canister loadings from the point-of-view of criticality, decay heat and emission sources. Copyright © 2018 Elsevier B.V. All rights reserved.

One step DNA assembly for combinatorial metabolic engineering.

PubMed

Coussement, Pieter; Maertens, Jo; Beauprez, Joeri; Van Bellegem, Wouter; De Mey, Marjan

2014-05-01

The rapid and efficient assembly of multi-step metabolic pathways for generating microbial strains with desirable phenotypes is a critical procedure for metabolic engineering, and remains a significant challenge in synthetic biology. Although several DNA assembly methods have been developed and applied for metabolic pathway engineering, many of them are limited by their suitability for combinatorial pathway assembly. The introduction of transcriptional (promoters), translational (ribosome binding site (RBS)) and enzyme (mutant genes) variability to modulate pathway expression levels is essential for generating balanced metabolic pathways and maximizing the productivity of a strain. We report a novel, highly reliable and rapid single strand assembly (SSA) method for pathway engineering. The method was successfully optimized and applied to create constructs containing promoter, RBS and/or mutant enzyme libraries. To demonstrate its efficiency and reliability, the method was applied to fine-tune multi-gene pathways. Two promoter libraries were simultaneously introduced in front of two target genes, enabling orthogonal expression as demonstrated by principal component analysis. This shows that SSA will increase our ability to tune multi-gene pathways at all control levels for the biotechnological production of complex metabolites, achievable through the combinatorial modulation of transcription, translation and enzyme activity. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Desmosome Assembly and Disassembly Are Membrane Raft-Dependent

PubMed Central

Faundez, Victor; Koval, Michael; Mattheyses, Alexa L.; Kowalczyk, Andrew P.

2014-01-01

Strong intercellular adhesion is critical for tissues that experience mechanical stress, such as the skin and heart. Desmosomes provide adhesive strength to tissues by anchoring desmosomal cadherins of neighboring cells to the intermediate filament cytoskeleton. Alterations in assembly and disassembly compromise desmosome function and may contribute to human diseases, such as the autoimmune skin blistering disease pemphigus vulgaris (PV). We previously demonstrated that PV auto-antibodies directed against the desmosomal cadherin desmoglein 3 (Dsg3) cause loss of adhesion by triggering membrane raft-mediated Dsg3 endocytosis. We hypothesized that raft membrane microdomains play a broader role in desmosome homeostasis by regulating the dynamics of desmosome assembly and disassembly. In human keratinocytes, Dsg3 is raft associated as determined by biochemical and super resolution immunofluorescence microscopy methods. Cholesterol depletion, which disrupts rafts, prevented desmosome assembly and adhesion, thus functionally linking rafts to desmosome formation. Interestingly, Dsg3 did not associate with rafts in cells lacking desmosomal proteins. Additionally, PV IgG-induced desmosome disassembly occurred by redistribution of Dsg3 into raft-containing endocytic membrane domains, resulting in cholesterol-dependent loss of adhesion. These findings demonstrate that membrane rafts are required for desmosome assembly and disassembly dynamics, suggesting therapeutic potential for raft targeting agents in desmosomal diseases such as PV. PMID:24498201

Overview of the 1997 Dirac High-Magnetic Series at LOS Alamos

NASA Astrophysics Data System (ADS)

Clark, D. A.; Campbell, L. J.; Forman, K. C.; Fowler, C. M.; Goettee, J. D.; Mielke, C. H.; Rickel, D. G.; Marshall, B. R.

2004-11-01

During the summer of 1997, a series of high magnetic field experiments was conducted at Los Alamos National Laboratory. Four experiments utilizing Russian built MC-1 generators, which can reach fields as high as 10 Megagauss, and four smaller strip generator experiments at fields near 1.5 Megagauss were conducted. Experiments mounted on the devices included magnetoresistance of high temperature superconductors and semiconductors, optical reflectivity (conductivity) of semiconductors, magnetization of a magnetic cluster material and a semiconductor, Faraday rotation in a semiconductor and a magnetic cluster material, and transmission spectroscopy of molecules. Brief descriptions of the experimental setups, magnetic field measurement techniques, field results and various experiments are presented. Magnetic field data and other information on Dirac `97 can be found at .

MANHATTAN: The View From Los Alamos of History's Most Secret Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carr, Alan Brady

This presentation covers the political and scientific events leading up to the creation of the Manhattan Project. The creation of the Manhattan Project’s three most significant sites--Los Alamos, Oak Ridge, and Hanford--is also discussed. The lecture concludes by exploring the use of the atomic bombs at the end of World War II. The presentation slides include three videos. The first is a short clip of the 100-ton Test. The 100-Ton Test was history’s largest measured blast at that point in time; it was a pre-test for Trinity, the world’s first nuclear detonation. The second clip features views of Trinity followedmore » a short statement by the Laboratory’s first director, J. Robert Oppenheimer. The final clip shows Norris Bradbury talking about arms control.« less

The Los Alamos Seismic Network (LASN): Recent Network Upgrades and Northern New Mexico Earthquake Catalog Updates

NASA Astrophysics Data System (ADS)

Roberts, P. M.; House, L. S.; Greene, M.; Ten Cate, J. A.; Schultz-Fellenz, E. S.; Kelley, R.

2012-12-01

From the first data recorded in the fall of 1973 to now, the Los Alamos Seismograph Network (LASN) has operated for nearly 40 years. LASN data have been used to locate more than 2,500 earthquakes in north-central New Mexico. The network was installed for seismic verification research, as well as to monitor and locate earthquakes near Los Alamos National Laboratory (LANL). LASN stations are the only earthquake monitoring stations in New Mexico north of Albuquerque. In the late 1970s, LASN included 22 stations spread over a geographic area of 150 km (N-S) by 350 km (E-W), of northern New Mexico. In the early 1980s, the available funding limited the stations that could be operated to a set of 7, located within an area of about 15 km (N-S) by 15 km (E-W), centered on Los Alamos. Over the last 3 years, 6 additional stations have been installed, which have considerably expanded the spatial coverage of the network. These new stations take advantage of broadband state-of-the-art sensors as well as digital recording and telemetry technology. Currently, 7 stations have broadband, three-component seismometers with digital telemetry, and the remaining 6 have traditional 1 Hz short-period seismometers with analog telemetry. In addition, a vertical array of accelerometers was installed in a wellbore on LANL property. This borehole station has 3-component digital strong-motion sensors. In addition, four forensic strong-motion accelerometers (SMA) are operated at LANL facilities. With 3 of the new broadband stations in and around the nearby Valles Caldera, LASN is now able to monitor any very small volcano-seismic events that may be associated with the caldera. We will present a complete description of the current LASN station, instrumentation and telemetry configurations, as well as the data acquisition and event-detection software structure used to record events in Earthworm. More than 2,000 earthquakes were detected and located in north-central New Mexico during the first 11

Los Alamos Shows Airport Security Technology at Work

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espy, Michelle; Schultz, Larry; Hunter, James

Los Alamos scientists have advanced a Magnetic Resonance Imaging (MRI) technology that may provide a breakthrough for screening liquids at airport security. They've added low-power X-ray data to the mix, and as a result have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new system is named MagRay. The goal is to quickly and accurately distinguish between liquids that visually appear identical. For example, what appears to be a bottle of white wine could potentially be nitromethane, a liquid that could be used to make an explosive. Both aremore » clear liquids, one would be perfectly safe on a commercial aircraft, the other would be strictly prohibited. How to tell them apart quickly without error at an airport security area is the focus of Michelle Espy, Larry Schultz and their team. In this video, Espy and the MagRay team explain how the new technology works, how they've developed an easy operator interface, and what the next steps might be in transitioning this technology to the private sector.« less

Organizational cultural survey of the Los Alamos Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

An Organizational Survey (OS) was administered at the Los Alamos Site that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental, safety, and health concerns, hazardous nature of work, safety and overall job satisfaction. The purpose of the OS is to measure in a quantitative and objective way the notion of ``culture;`` that is, the values, attitudes, and beliefs of the individuals working within the organization. In addition, through the OS, a broad sample of individuals can be reached that would probably not be interviewed or observed duringmore » the course of a typical assessment. The OS also provides a descriptive profile of the organization at one point in time that can then be compared to a profile taken at a different point in time to assess changes in the culture of the organization. While comparisons among groups are made, it is not the purpose of this report to make evaluative statements of which profile may be positive or negative. However, using the data presented in this report in conjunction with other evaluative activities, may provide useful insight into the organization.« less

Organizational cultural survey of the Los Alamos Site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

An Organizational Survey (OS) was administered at the Los Alamos Site that queried employees on the subjects of organizational culture, various aspects of communications, employee commitment, work group cohesion, coordination of work, environmental, safety, and health concerns, hazardous nature of work, safety and overall job satisfaction. The purpose of the OS is to measure in a quantitative and objective way the notion of culture;'' that is, the values, attitudes, and beliefs of the individuals working within the organization. In addition, through the OS, a broad sample of individuals can be reached that would probably not be interviewed or observed duringmore » the course of a typical assessment. The OS also provides a descriptive profile of the organization at one point in time that can then be compared to a profile taken at a different point in time to assess changes in the culture of the organization. While comparisons among groups are made, it is not the purpose of this report to make evaluative statements of which profile may be positive or negative. However, using the data presented in this report in conjunction with other evaluative activities, may provide useful insight into the organization.« less

Los Alamos radiation transport code system on desktop computing platforms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Briesmeister, J.F.; Brinkley, F.W.; Clark, B.A.

The Los Alamos Radiation Transport Code System (LARTCS) consists of state-of-the-art Monte Carlo and discrete ordinates transport codes and data libraries. These codes were originally developed many years ago and have undergone continual improvement. With a large initial effort and continued vigilance, the codes are easily portable from one type of hardware to another. The performance of scientific work-stations (SWS) has evolved to the point that such platforms can be used routinely to perform sophisticated radiation transport calculations. As the personal computer (PC) performance approaches that of the SWS, the hardware options for desk-top radiation transport calculations expands considerably. Themore » current status of the radiation transport codes within the LARTCS is described: MCNP, SABRINA, LAHET, ONEDANT, TWODANT, TWOHEX, and ONELD. Specifically, the authors discuss hardware systems on which the codes run and present code performance comparisons for various machines.« less

Noncanonical self-assembly of multifunctional DNA nanoflowers for biomedical applications.

PubMed

Zhu, Guizhi; Hu, Rong; Zhao, Zilong; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

2013-11-06

DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via rolling circle replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery.

Noncanonical self-assembly of multifunctional DNA nanoflowers for biomedical applications

PubMed Central

Zhu, Guizhi; Hu, Rong; Zhao, Zilong; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

2013-01-01

DNA nanotechnology has been extensively explored to assemble various functional nanostructures for versatile applications. Mediated by Watson-Crick base-pairing, these DNA nanostructures have been conventionally assembled through hybridization of many short DNA building blocks. Here we report the noncanonical self-assembly of multifunctional DNA nanostructures, termed as nanoflowers (NFs), and the versatile biomedical applications. These NFs were assembled from long DNA building blocks generated via Rolling Circle Replication (RCR) of a designer template. NF assembly was driven by liquid crystallization and dense packaging of building blocks, without relying on Watson-Crick base-pairing between DNA strands, thereby avoiding the otherwise conventional complicated DNA sequence design. NF sizes were readily tunable in a wide range, by simply adjusting such parameters as assembly time and template sequences. NFs were exceptionally resistant to nuclease degradation, denaturation, or dissociation at extremely low concentration, presumably resulting from the dense DNA packaging in NFs. The exceptional biostability is critical for biomedical applications. By rational design, NFs can be readily incorporated with myriad functional moieties. All these properties make NFs promising for versatile applications. As a proof-of-principle demonstration, in this study, NFs were integrated with aptamers, bioimaging agents, and drug loading sites, and the resultant multifunctional NFs were demonstrated for selective cancer cell recognition, bioimaging, and targeted anticancer drug delivery. PMID:24164620

Clean then Assemble Versus Assemble then Clean: Several Comparisons

NASA Technical Reports Server (NTRS)

Welker, Roger W.

2004-01-01

Cleanliness of manufactured parts and assemblies is a significant issue in many industries including disk drives, semiconductors, aerospace, and medical devices. Clean manufacturing requires cleanroom floor space and cleaning technology that are both expensive to own and expensive to operate. Strategies to reduce these costs are an important consideration. One strategy shown to be effective at reducing costs is to assemble parts into subassemblies and then clean the subassembly, rather than clean the individual parts first and then assemble them. One advantage is that assembly outside of the cleanroom reduces the amount of cleanroom floor space and its associated operating cost premium. A second advantage is that this strategy reduces the number of individual parts that must be cleaned prior to assembly, reducing the number of cleaning baskets, handling and, possibly, reducing the number of cleaners. The assemble then clean strategy also results in a part that is significantly cleaner because contamination generated during the assembly steps are more effectively removed that normally can be achieved by hand wiping after assembly in the cleanroom.

Initial Validation of Robotic Operations for In-Space Assembly of a Large Solar Electric Propulsion Transport Vehicle

NASA Technical Reports Server (NTRS)

Komendera, Erik E.; Dorsey, John T.

2017-01-01

Developing a capability for the assembly of large space structures has the potential to increase the capabilities and performance of future space missions and spacecraft while reducing their cost. One such application is a megawatt-class solar electric propulsion (SEP) tug, representing a critical transportation ability for the NASA lunar, Mars, and solar system exploration missions. A series of robotic assembly experiments were recently completed at Langley Research Center (LaRC) that demonstrate most of the assembly steps for the SEP tug concept. The assembly experiments used a core set of robotic capabilities: long-reach manipulation and dexterous manipulation. This paper describes cross-cutting capabilities and technologies for in-space assembly (ISA), applies the ISA approach to a SEP tug, describes the design and development of two assembly demonstration concepts, and summarizes results of two sets of assembly experiments that validate the SEP tug assembly steps.

Plasma Pyrolysis Assembly Regeneration Evaluation

NASA Technical Reports Server (NTRS)

Medlen, Amber; Abney, Morgan B.; Miller, Lee A.

2011-01-01

In April 2010 the Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS). This technology requires hydrogen to recover oxygen from carbon dioxide. This results in the production of water and methane. Water is electrolyzed to provide oxygen to the crew. Methane is vented to space resulting in a loss of valuable hydrogen and unreduced carbon dioxide. This is not critical for ISS because of the water resupply from Earth. However, in order to have enough oxygen for long-term missions, it will be necessary to recover the hydrogen to maximize oxygen recovery. Thus, the Plasma Pyrolysis Assembly (PPA) was designed to recover hydrogen from methane. During operation, the PPA produces small amounts of carbon that can ultimately reduce performance by forming on the walls and windows of the reactor chamber. The carbon must be removed, although mechanical methods are highly inefficient, thus chemical methods are of greater interest. The purpose of this effort was to determine the feasibility of chemically removing the carbon from the walls and windows of a PPA reactor using a pure carbon dioxide stream.

The space station assembly phase: Flight telerobotic servicer feasibility, volume 1

NASA Technical Reports Server (NTRS)

Smith, Jeffrey H.; Gyamfi, Max A.; Volkmer, Kent; Zimmerman, Wayne F.

1987-01-01

The question is addressed which was raised by the Critical Evaluation Task Force (CETF) analysis of the space station: if a Flight Telerobotic Servicer (FTS) of a given technical risk could be built for use during space station assembly, could it save significant extravehicular (EVA) resources. Key issues and trade-offs associated with using an FTS to aid in space station assembly phase tasks such as construction and servicing are identified. A methodology is presented that incorporates assessment of candidate assembly phase tasks, telerobotics performance capabilities, development costs, operational constraints (STS and proximity operations), maintenance, attached payloads, and polar platforms. A discussion of the issues is presented with focus on potential FTS roles: (1) as a research-oriented test bed to learn more about space usage of telerobotics; (2) as a research-based test bed with an experimental demonstration orientation and limited assembly and servicing applications; or (3) as an operational system to augment EVA, to aid the construction of the space station, and to reduce the programmatic (schedule) risk by increasing the flexibility of mission operations. During the course of the study, the baseline configuration was modified into Phase 1 (a station assembled in 12 flights), and Phase 2 (a station assembled over a 30 flight period) configuration.

ZPR-3 Assembly 11 : A cylindrical sssembly of highly enriched uranium and depleted uranium with an average {sup 235}U enrichment of 12 atom % and a depleted uranium reflector.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lell, R. M.; McKnight, R. D.; Tsiboulia, A.

2010-09-30

Over a period of 30 years, more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited for nuclear data validation and to form the basis for criticality safety benchmarks. A number of the Argonne ZPR/ZPPR critical assemblies have been evaluated as ICSBEP and IRPhEP benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physicsmore » benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. ZPR-3 Assembly 11 (ZPR-3/11) was designed as a fast reactor physics benchmark experiment with an average core {sup 235}U enrichment of approximately 12 at.% and a depleted uranium reflector. Approximately 79.7% of the total fissions in this assembly occur above 100 keV, approximately 20.3% occur below 100 keV, and essentially none below 0.625 eV - thus the classification as a 'fast' assembly. This assembly is Fast Reactor Benchmark No. 8 in the Cross Section Evaluation Working

Stormwater Pollution Prevention Plan for the TA-03-38 Carpenter's Shop, Los Alamos National Laboratory, Revision 3, January 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgin, Jillian Elizabeth

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector A–Timber Products, Subsector A4 (Wood Products Facilities not elsewhere classified) as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-03-38 Carpenter’s Shop at Los Alamosmore » National Laboratory. Los Alamos National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-03-38 Carpenter’s Shop and associated areas. The current permit expires at midnight on June 4, 2020.« less

The critical thinking curriculum model

NASA Astrophysics Data System (ADS)

Robertson, William Haviland

The Critical Thinking Curriculum Model (CTCM) utilizes a multidisciplinary approach that integrates effective learning and teaching practices with computer technology. The model is designed to be flexible within a curriculum, an example for teachers to follow, where they can plug in their own critical issue. This process engages students in collaborative research that can be shared in the classroom, across the country or around the globe. The CTCM features open-ended and collaborative activities that deal with current, real world issues which leaders are attempting to solve. As implemented in the Critical Issues Forum (CIF), an educational program administered by Los Alamos National Laboratory (LANL), the CTCM encompasses the political, social/cultural, economic, and scientific realms in the context of a current global issue. In this way, students realize the importance of their schooling by applying their efforts to an endeavor that ultimately will affect their future. This study measures student attitudes toward science and technology and the changes that result from immersion in the CTCM. It also assesses the differences in student learning in science content and problem solving for students involved in the CTCM. A sample of 24 students participated in classrooms at two separate high schools in New Mexico. The evaluation results were analyzed using SPSS in a MANOVA format in order to determine the significance of the between and within-subjects effects. A comparison ANOVA was done for each two-way MANOVA to see if the comparison groups were equal. Significant findings were validated using the Scheffe test in a Post Hoc analysis. Demographic information for the sample population was recorded and tracked, including self-assessments of computer use and availability. Overall, the results indicated that the CTCM did help to increase science content understanding and problem-solving skills for students, thereby positively effecting critical thinking. No matter if the

CRITICAL EXPERIMENT TANK (CET) REACTOR HAZARDS SUMMARY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becar, N.J.; Kunze, J.F.; Pincock, G..D.

1961-03-31

The Critical Experiment Tank (CET) reactor assembly, the associated systems, and the Low Power Test Facility in which the reactor is to be operated are described. An evaluation and summary of the hazards associated with the operation of the CET reactor in the LPTF at the ldsho Test Station are also presented. (auth)

Metagenome assembly through clustering of next-generation sequencing data using protein sequences.

PubMed

Sim, Mikang; Kim, Jaebum

2015-02-01

The study of environmental microbial communities, called metagenomics, has gained a lot of attention because of the recent advances in next-generation sequencing (NGS) technologies. Microbes play a critical role in changing their environments, and the mode of their effect can be solved by investigating metagenomes. However, the difficulty of metagenomes, such as the combination of multiple microbes and different species abundance, makes metagenome assembly tasks more challenging. In this paper, we developed a new metagenome assembly method by utilizing protein sequences, in addition to the NGS read sequences. Our method (i) builds read clusters by using mapping information against available protein sequences, and (ii) creates contig sequences by finding consensus sequences through probabilistic choices from the read clusters. By using simulated NGS read sequences from real microbial genome sequences, we evaluated our method in comparison with four existing assembly programs. We found that our method could generate relatively long and accurate metagenome assemblies, indicating that the idea of using protein sequences, as a guide for the assembly, is promising. Copyright © 2015 Elsevier B.V. All rights reserved.

Facile "modular assembly" for fast construction of a highly oriented crystalline MOF nanofilm.

PubMed

Xu, Gang; Yamada, Teppei; Otsubo, Kazuya; Sakaida, Shun; Kitagawa, Hiroshi

2012-10-10

The preparation of crystalline, ordered thin films of metal-organic frameworks (MOFs) will be a critical process for MOF-based nanodevices in the future. MOF thin films with perfect orientation and excellent crystallinity were formed with novel nanosheet-structured components, Cu-TCPP [TCPP = 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin], by a new "modular assembly" strategy. The modular assembly process involves two steps: a "modularization" step is used to synthesize highly crystalline "modules" with a nanosized structure that can be conveniently assembled into a thin film in the following "assembly" step. With this method, MOF thin films can easily be set up on different substrates at very high speed with controllable thickness. This new approach also enabled us to prepare highly oriented crystalline thin films of MOFs that cannot be prepared in thin-film form by traditional techniques.

Floodplain Assessment for the Middle Los Alamos Canyon Aggregate Area Investigations in Technical Area 02 at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hathcock, Charles Dean

The proposed action being assessed in this document occurs in TA-02 in the bottom of Los Alamos Canyon. The DOE proposes to conduct soil sampling at AOC 02-011 (d), AOC 02- 011(a)(ii), and SWMU 02-005, and excavate soils in AOC 02-011(a)(ii) as part of a corrective actions effort. Additional shallow surface soil samples (soil grab samples) will be collected throughout the TA-02 area, including within the floodplain, to perform ecotoxicology studies (Figures 1 and 2). The excavation boundaries in AOC 02-011(a)(ii) are slightly within the delineated 100-year floodplain. The project will use a variety of techniques for soil sampling andmore » remediation efforts to include hand/digging, standard hand auger/sampling, excavation using machinery such as backhoe and front end loader and small drill rig. Heavy equipment will traverse the floodplain and spoils piles will be staged in the floodplain within developed or previously disturbed areas (e.g., existing paved roads and parking areas). The project will utilize and maintain appropriate best management practices (BMPs) to contain excavated materials, and all pollutants, including oil from machinery/vehicles. The project will stabilize disturbed areas as appropriate at the end of the project.« less

Chemical decontamination technical resources at Los Alamos National Laboratory (2008)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Murray E

This document supplies information resources for a person seeking to create planning or pre-planning documents for chemical decontamination operations. A building decontamination plan can be separated into four different sections: Pre-planning, Characterization, Decontamination (Initial response and also complete cleanup), and Clearance. Of the identified Los Alamos resources, they can be matched with these four sections: Pre-planning -- Dave Seidel, EO-EPP, Emergency Planning and Preparedness; David DeCroix and Bruce Letellier, D-3, Computational fluids modeling of structures; Murray E. Moore, RP-2, Aerosol sampling and ventilation engineering. Characterization (this can include development projects) -- Beth Perry, IAT-3, Nuclear Counterterrorism Response (SNIPER database); Fernandomore » Garzon, MPA-11, Sensors and Electrochemical Devices (development); George Havrilla, C-CDE, Chemical Diagnostics and Engineering; Kristen McCabe, B-7, Biosecurity and Public Health. Decontamination -- Adam Stively, EO-ER, Emergency Response; Dina Matz, IHS-IP, Industrial hygiene; Don Hickmott, EES-6, Chemical cleanup. Clearance (validation) -- Larry Ticknor, CCS-6, Statistical Sciences.« less

Small-Molecule Effectors of Hepatitis B Virus Capsid Assembly Give Insight into Virus Life Cycle▿

PubMed Central

Bourne, Christina; Lee, Sejin; Venkataiah, Bollu; Lee, Angela; Korba, Brent; Finn, M. G.; Zlotnick, Adam

2008-01-01

The relationship between the physical chemistry and biology of self-assembly is poorly understood, but it will be critical to quantitatively understand infection and for the design of antivirals that target virus genesis. Here we take advantage of heteroaryldihydropyrimidines (HAPs), which affect hepatitis B virus (HBV) assembly, to gain insight and correlate in vitro assembly with HBV replication in culture. Based on a low-resolution crystal structure of a capsid-HAP complex, a closely related series of HAPs were designed and synthesized. These differentially strengthen the association between neighboring capsid proteins, alter the kinetics of assembly, and give rise to aberrant structures incompatible with a functional capsid. The chemical nature of the HAP variants correlated well with the structure of the HAP binding pocket. The thermodynamics and kinetics of in vitro assembly had strong and predictable effects on product morphology. However, only the kinetics of in vitro assembly had a strong correlation with inhibition of HBV replication in HepG2.2.15 cells; there was at best a weak correlation between assembly thermodynamics and replication. The correlation between assembly kinetics and virus suppression implies a competition between successful assembly and misassembly, small molecule induced or otherwise. This is a predictive and testable model for the mechanism of action of assembly effectors. PMID:18684823

Role of Histone Acetylation in the Assembly and Modulation of Chromatin Structures

PubMed Central

Annunziato, Anthony T.; Hansen, Jeffrey C.

2000-01-01

The acetylation of the core histone N-terminal “tail” domains is now recognized as a highly conserved mechanism for regulating chromatin functional states. The following article examines possible roles of acetylation in two critically important cellular processes: replication-coupled nucleosome assembly, and reversible transitions in chromatin higher order structure. After a description of the acetylation of newly synthesized histones, and of the likely acetyltransferases involved, an overview of histone octamer assembly is presented. Our current understanding of the factors thought to assemble chromatin in vivo is then described. Genetic and biochemical investigations of the function the histone tails, and their acetylation, in nucleosome assembly are detailed, followed by an analysis of the importance of histone deacetylation in the maturation of newly replicated chromatin. In the final section the involvement of the histone tail domains in chromatin higher order structures is addressed, along with the role of histone acetylation in chromatin folding. Suggestions for future research are offered in the concluding remarks. PMID:11097424

Ordered patterns and structures via interfacial self-assembly: superlattices, honeycomb structures and coffee rings.

PubMed

Ma, Hongmin; Hao, Jingcheng

2011-11-01

Self-assembly is now being intensively studied in chemistry, physics, biology, and materials engineering and has become an important "bottom-up" approach to create intriguing structures for different applications. Self-assembly is not only a practical approach for creating a variety of nanostructures, but also shows great superiority in building hierarchical structures with orders on different length scales. The early work in self-assembly focused on molecular self-assembly in bulk solution, including the resultant dye aggregates, liposomes, vesicles, liquid crystals, gels and so on. Interfacial self-assembly has been a great concern over the last two decades, largely because of the unique and ingenious roles of this method for constructing materials at interfaces, such as self-assembled monolayers, Langmuir-Blodgett films, and capsules. Nanocrystal superlattices, honeycomb films and coffee rings are intriguing structural materials with more complex features and can be prepared by interfacial self-assembly on different length scales. In this critical review, we outline the recent development in the preparation and application of colloidal nanocrystal superlattices, honeycomb-patterned macroporous structures by the breath figure method, and coffee-ring-like patterns (247 references). This journal is © The Royal Society of Chemistry 2011

New Developments in Proton Radiography at the Los Alamos Neutron Science Center (LANSCE)

DOE PAGES

Morris, C. L.; Brown, E. N.; Agee, C.; ...

2015-12-30

An application of nuclear physics, a facility for using protons for flash radiography, was developed at the Los Alamos Neutron Science Center (LANSCE). Protons have proven far superior to high energy x-rays for flash radiography because of their long mean free path, good position resolution, and low scatter background. Although this facility is primarily used for studying very fast phenomena such as high explosive driven experiments, it is finding increasing application to other fields, such as tomography of static objects, phase changes in materials and the dynamics of chemical reactions. The advantages of protons are discussed, data from some recentmore » experiments will be reviewed and concepts for new techniques are introduced.« less

Performance of the New Los Alamos UCN Source and Implications for Future Experiments

NASA Astrophysics Data System (ADS)

Makela, Mark; LANL UCN Team

2017-01-01

The Los Alamos Ultracold Neutron (UCN) source was replaced during this past summer and has been commissioned during the last few months. The new source is the result of lessons learned during the 10 year operation of the first UCN source and extensive Monte Carlo analysis. The new source is a spallation driven source based on a solid deuterium UCN moderator similar the previous one. This talk will present an overview of the new source design and the results of commissioning tests. The talk will conclude with a brief overview of the implications of source performance on the neutron lifetime and LANL nEDM experiments. This work was funded by LANL LDRD.

Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria

PubMed Central

Chahales, Peter; Thanassi, David G.

2015-01-01

Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities such as biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hairlike fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections. PMID:26542038

Launch and Assembly Reliability Analysis for Human Space Exploration Missions

NASA Technical Reports Server (NTRS)

Cates, Grant; Gelito, Justin; Stromgren, Chel; Cirillo, William; Goodliff, Kandyce

2012-01-01

NASA's future human space exploration strategy includes single and multi-launch missions to various destinations including cis-lunar space, near Earth objects such as asteroids, and ultimately Mars. Each campaign is being defined by Design Reference Missions (DRMs). Many of these missions are complex, requiring multiple launches and assembly of vehicles in orbit. Certain missions also have constrained departure windows to the destination. These factors raise concerns regarding the reliability of launching and assembling all required elements in time to support planned departure. This paper describes an integrated methodology for analyzing launch and assembly reliability in any single DRM or set of DRMs starting with flight hardware manufacturing and ending with final departure to the destination. A discrete event simulation is built for each DRM that includes the pertinent risk factors including, but not limited to: manufacturing completion; ground transportation; ground processing; launch countdown; ascent; rendezvous and docking, assembly, and orbital operations leading up to trans-destination-injection. Each reliability factor can be selectively activated or deactivated so that the most critical risk factors can be identified. This enables NASA to prioritize mitigation actions so as to improve mission success.

Feedbacks between community assembly and habitat selection shape variation in local colonization

USGS Publications Warehouse

Kraus, J.M.; Vonesh, J.R.

2010-01-01

1. Non-consumptive effects of predators are increasingly recognized as important drivers of community assembly and structure. Specifically, habitat selection responses to top predators during colonization and oviposition can lead to large differences in aquatic community structure, composition and diversity. 2. These differences among communities due to predators may develop as communities assemble, potentially altering the relative quality of predator vs. predator-free habitats through time. If so, community assembly would be expected to modify the subsequent behavioural responses of colonists to habitats containing top predators. Here, we test this hypothesis by manipulating community assembly and the presence of fish in experimental ponds and measuring their independent and combined effects on patterns of colonization by insects and amphibians. 3. Assembly modified habitat selection of dytscid beetles and hylid frogs by decreasing or even reversing avoidance of pools containing blue-spotted sunfish (Enneacanthus gloriosus). However, not all habitat selection responses to fish depended on assembly history. Hydrophilid beetles and mosquitoes avoided fish while chironomids were attracted to fish pools, regardless of assembly history. 4. Our results show that community assembly causes taxa-dependent feedbacks that can modify avoidance of habitats containing a top predator. Thus, non-consumptive effects of a top predator on community structure change as communities assemble and effects of competitors and other predators combine with the direct effects of top predators to shape colonization. 5. This work reinforces the importance of habitat selection for community assembly in aquatic systems, while illustrating the range of factors that may influence colonization rates and resulting community structure. Directly manipulating communities both during colonization and post-colonization is critical for elucidating how sequential processes interact to shape communities.

Inlet nozzle assembly

DOEpatents

Christiansen, David W.; Karnesky, Richard A.; Precechtel, Donald R.; Smith, Bob G.; Knight, Ronald C.

1987-01-01

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Inlet nozzle assembly

DOEpatents

Christiansen, D.W.; Karnesky, R.A.; Knight, R.C.; Precechtel, D.R.; Smith, B.G.

1985-09-09

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Multifunctional Self-Assembled Monolayers for Organic Field-Effect Transistors

NASA Astrophysics Data System (ADS)

Cernetic, Nathan

Organic field effect transistors (OFETs) have the potential to reach commercialization for a wide variety of applications such as active matrix display circuitry, chemical and biological sensing, radio-frequency identification devices and flexible electronics. In order to be commercially competitive with already at-market amorphous silicon devices, OFETs need to approach similar performance levels. Significant progress has been made in developing high performance organic semiconductors and dielectric materials. Additionally, a common route to improve the performance metric of OFETs is via interface modification at the critical dielectric/semiconductor and electrode/semiconductor interface which often play a significant role in charge transport properties. These metal oxide interfaces are typically modified with rationally designed multifunctional self-assembled monolayers. As means toward improving the performance metrics of OFETs, rationally designed multifunctional self-assembled monolayers are used to explore the relationship between surface energy, SAM order, and SAM dipole on OFET performance. The studies presented within are (1) development of a multifunctional SAM capable of simultaneously modifying dielectric and metal surface while maintaining compatibility with solution processed techniques (2) exploration of the relationship between SAM dipole and anchor group on graphene transistors, and (3) development of self-assembled monolayer field-effect transistor in which the traditional thick organic semiconductor is replaced by a rationally designed self-assembled monolayer semiconductor. The findings presented within represent advancement in the understanding of the influence of self-assembled monolayers on OFETs as well as progress towards rationally designed monolayer transistors.

Engineering aqueous fiber assembly into silk-elastin-like protein polymers.

PubMed

Zeng, Like; Jiang, Linan; Teng, Weibing; Cappello, Joseph; Zohar, Yitshak; Wu, Xiaoyi

2014-07-01

Self-assembled peptide/protein nanofibers are valuable 1D building blocks for creating complex structures with designed properties and functions. It is reported that the self-assembly of silk-elastin-like protein polymers into nanofibers or globular aggregates in aqueous solutions can be modulated by tuning the temperature of the protein solutions, the size of the silk blocks, and the charge of the elastin blocks. A core-sheath model is proposed for nanofiber formation, with the silk blocks in the cores and the hydrated elastin blocks in the sheaths. The folding of the silk blocks into stable cores--affected by the size of the silk blocks and the charge of the elastin blocks--plays a critical role in the assembly of silk-elastin nanofibers. Furthermore, enhanced hydrophobic interactions between the elastin blocks at elevated temperatures greatly influence the nanoscale features of silk-elastin nanofibers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spatial Extent of Charge Repulsion Regulates Assembly Pathways for Lysozyme Amyloid Fibrils

PubMed Central

Hill, Shannon E.; Miti, Tatiana; Richmond, Tyson; Muschol, Martin

2011-01-01

Formation of large protein fibrils with a characteristic cross β-sheet architecture is the key indicator for a wide variety of systemic and neurodegenerative amyloid diseases. Recent experiments have strongly implicated oligomeric intermediates, transiently formed during fibril assembly, as critical contributors to cellular toxicity in amyloid diseases. At the same time, amyloid fibril assembly can proceed along different assembly pathways that might or might not involve such oligomeric intermediates. Elucidating the mechanisms that determine whether fibril formation proceeds along non-oligomeric or oligomeric pathways, therefore, is important not just for understanding amyloid fibril assembly at the molecular level but also for developing new targets for intervening with fibril formation. We have investigated fibril formation by hen egg white lysozyme, an enzyme for which human variants underlie non-neuropathic amyloidosis. Using a combination of static and dynamic light scattering, atomic force microscopy and circular dichroism, we find that amyloidogenic lysozyme monomers switch between three different assembly pathways: from monomeric to oligomeric fibril assembly and, eventually, disordered precipitation as the ionic strength of the solution increases. Fibril assembly only occurred under conditions of net repulsion among the amyloidogenic monomers while net attraction caused precipitation. The transition from monomeric to oligomeric fibril assembly, in turn, occurred as salt-mediated charge screening reduced repulsion among individual charged residues on the same monomer. We suggest a model of amyloid fibril formation in which repulsive charge interactions are a prerequisite for ordered fibril assembly. Furthermore, the spatial extent of non-specific charge screening selects between monomeric and oligomeric assembly pathways by affecting which subset of denatured states can form suitable intermolecular bonds and by altering the energetic and entropic

jsc2018m000297_Investigation_Seeks_to_Create_Self-Assembling_Materials-MP4

NASA Image and Video Library

2018-05-14

Investigation Seeks to Create Self-Assembling Materials------ As we travel farther into space, clever solutions to problems like engine part malfunctions and other possible mishaps will be a vital part of the planning process. 3D printing, or additive manufacturing, is an emerging technology that may be used to custom-create mission-critical parts. An integral piece of this process is understanding how particle shape, size distribution and packing behavior affect the manufacturing process. The Advanced Colloids Experiment-Temperature-7 investigation (ACE-T-7) aboard the International Space Station explores the feasibility of creating self-assembling microscopic particles for use in the manufacturing of materials during spaceflight. Read more about ACE-T-& here: https://www.nasa.gov/feature/investigation-seeks-to-create-self-assembling-materials

Two criteria for the selection of assembly plans - Maximizing the flexibility of sequencing the assembly tasks and minimizing the assembly time through parallel execution of assembly tasks

NASA Technical Reports Server (NTRS)

Homem De Mello, Luiz S.; Sanderson, Arthur C.

1991-01-01

The authors introduce two criteria for the evaluation and selection of assembly plans. The first criterion is to maximize the number of different sequences in which the assembly tasks can be executed. The second criterion is to minimize the total assembly time through simultaneous execution of assembly tasks. An algorithm that performs a heuristic search for the best assembly plan over the AND/OR graph representation of assembly plans is discussed. Admissible heuristics for each of the two criteria introduced are presented. Some implementation issues that affect the computational efficiency are addressed.

Mineral Surface Chemistry and Nanoparticle-aggregation Control Membrane Self-Assembly

PubMed Central

Sahai, Nita; Kaddour, Hussein; Dalai, Punam; Wang, Ziqiu; Bass, Garrett; Gao, Min

2017-01-01

The self-assembly of lipid bilayer membranes to enclose functional biomolecules, thus defining a “protocell,” was a seminal moment in the emergence of life on Earth and likely occurred at the micro-environment of the mineral-water interface. Mineral-lipid interactions are also relevant in biomedical, industrial and technological processes. Yet, no structure-activity relationships (SARs) have been identified to predict lipid self-assembly at mineral surfaces. Here we examined the influence of minerals on the self-assembly and survival of vesicles composed of single chain amphiphiles as model protocell membranes. The apparent critical vesicle concentration (CVC) increased in the presence of positively-charged nanoparticulate minerals at high loadings (mg/mL) suggesting unfavorable membrane self-assembly in such situations. Above the CVC, initial vesicle formation rates were faster in the presence of minerals. Rates were correlated with the mineral’s isoelectric point (IEP) and reactive surface area. The IEP depends on the crystal structure, chemical composition and surface hydration. Thus, membrane self-assembly showed rational dependence on fundamental mineral properties. Once formed, membrane permeability (integrity) was unaffected by minerals. Suggesting that, protocells could have survived on rock surfaces. These SARs may help predict the formation and survival of protocell membranes on early Earth and other rocky planets, and amphiphile-mineral interactions in diverse other phenomena. PMID:28266537

Mineral Surface Chemistry and Nanoparticle-aggregation Control Membrane Self-Assembly

NASA Astrophysics Data System (ADS)

Sahai, Nita; Kaddour, Hussein; Dalai, Punam; Wang, Ziqiu; Bass, Garrett; Gao, Min

2017-03-01

The self-assembly of lipid bilayer membranes to enclose functional biomolecules, thus defining a “protocell,” was a seminal moment in the emergence of life on Earth and likely occurred at the micro-environment of the mineral-water interface. Mineral-lipid interactions are also relevant in biomedical, industrial and technological processes. Yet, no structure-activity relationships (SARs) have been identified to predict lipid self-assembly at mineral surfaces. Here we examined the influence of minerals on the self-assembly and survival of vesicles composed of single chain amphiphiles as model protocell membranes. The apparent critical vesicle concentration (CVC) increased in the presence of positively-charged nanoparticulate minerals at high loadings (mg/mL) suggesting unfavorable membrane self-assembly in such situations. Above the CVC, initial vesicle formation rates were faster in the presence of minerals. Rates were correlated with the mineral’s isoelectric point (IEP) and reactive surface area. The IEP depends on the crystal structure, chemical composition and surface hydration. Thus, membrane self-assembly showed rational dependence on fundamental mineral properties. Once formed, membrane permeability (integrity) was unaffected by minerals. Suggesting that, protocells could have survived on rock surfaces. These SARs may help predict the formation and survival of protocell membranes on early Earth and other rocky planets, and amphiphile-mineral interactions in diverse other phenomena.

Threatened and Endangered Species Habitat Management Plan for Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, David Charles; Hathcock, Charles Dean

Los Alamos National Laboratory’s (LANL) Threatened and Endangered Species Habitat Management Plan (HMP) fulfills a commitment made to the U.S. Department of Energy (DOE) in the “Final Environmental Impact Statement for the Dual-Axis Radiographic Hydrodynamic Test Facility Mitigation Action Plan” (DOE 1996). The HMP received concurrence from the U.S. Fish and Wildlife Service (USFWS) in 1999 (USFWS consultation numbers 2-22-98-I-336 and 2-22-95-I-108). This 2015 update retains the management guidelines from the 1999 HMP for listed species, updates some descriptive information, and adds the New Mexico Meadow Jumping Mouse (Zapus hudsonius luteus) and Yellow-billed Cuckoo (Coccyzus americanus) which were federally listedmore » in 2014 (Keller 2015: USFWS consultation number 02ENNM00- 2015-I-0538).« less

Architecture and assembly of the Bacillus subtilis spore coat.

PubMed

Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J

2014-01-01

Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of "nanodot" particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

Architecture and Assembly of the Bacillus subtilis Spore Coat

PubMed Central

Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J.

2014-01-01

Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of “nanodot” particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

Reconnaissance assessment of erosion and sedimentation in the Canada de los Alamos basin, Los Angeles and Ventura Counties, California

USGS Publications Warehouse

Knott, J.M.

1980-01-01

An assessment of present erosion and sedimentation conditions in the Ca?ada de los Alamos basin was made to aid in estimating the impact of off-road-vehicle use on the sediment yield of the basin. Impacts of off-road vehicles were evaluated by reconnaissance techniques and by comparing the study area with other offroad-vehicle sites in California. Major-storm sediment yields for the basin were estimated using empirical equations developed for the Transverse Ranges and measurements of gully erosion in a representative off-road-vehicle basin. Normal major-storm yields of 73,200 cubic yards would have to be increased to about 98,000 cubic yards to account for the existing level of accelerated erosion caused by off-road vehicles. Long-term sediment yield of the Ca?ada de los Alamos basin upstream from its confluence with Gorman Creek, under present conditions of off-road-vehicle use, is approximately 420 cubic yards per square mile per year--a rate that is considerably lower than a previous estimate of 1,270 cubic yards per square mile per year for the total catchment area above Pyramid Lake.

Self-assembly in Dipolar Fluids

NASA Astrophysics Data System (ADS)

Ronti, Michela; Kantorovich, Sofia

We are studying low temperature structural transitions in dipolar hard spheres (DHS), combining grand-canonical Monte Carlo simulations and direct analytical theoretical calculations. DHS is characterized by long-range anisotropic interactions: it consists of a point dipole at the center of a hard sphere. We are interested in low temperature and low density phase behaviour of DHS systems. From a theoretical point of view the process of self-assembly is not responsible for a phase transition; this belief was completely reverted by theoretical studies showing that the process of self-assembly is alone capable to induce phase transition. On the other hand in the last years it was proved that no sign of critical behaviour is observed, implementing efficient and tailored Monte Carlo algorithms. Moreover a theoretical approach based on Density Functional Theory was developed: a series of structural transitions were discovered providing evidence of a hierarchy in the structures on cooling. We are performing free-energy calculations in order to draw the phase diagram of DHS model. Comparing the numerical results with the theoretical ones shed light on the scenario of temperature induced structural transitions in magnetic nanocolloids. Etn-COLLDENSE (H2020-MCSA-ITN-2014, Grant No. 642774).

Mounting for Fabrication, Metrology, and Assembly of Full Shell Grazing Incidence Optics

NASA Technical Reports Server (NTRS)

Roche, Jacqueline M.; Gubarev, Mikhail V.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Ramsey, Brian D.; Elsner, Ronald F.

2014-01-01

Future x-ray telescopes will likely require lightweight mirrors to attain the large collecting areas needed to accomplish the science objectives. Understanding and demonstrating processes now is critical to achieving sub-arcsecond performance in the future. Consequently, designs not only of the mirrors but of fixtures for supporting them during fabrication, metrology, handling, assembly, and testing must be adequately modeled and verified. To this end, MSFC is using finite-element modeling to study the effects of mounting on full-shell grazing-incidence mirrors, during all processes leading to flight mirror assemblies. Here we report initial results of this study.

Sensor mount assemblies and sensor assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David H

2012-04-10

Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and themore » tooth is formed on the second end of the first finger.« less

Overview and Status of the Los Alamos PSR Injection Upgrade Project

NASA Astrophysics Data System (ADS)

Fitzgerald, D. H.; Ahn, H.; Blind, B.; Borden, M. J.; Macek, R. J.; Neri, F.; Rose, C. R.; Thiessen, H. A.; Wilkinson, C. A.; Zumbro, M. V.

1997-05-01

An upgrade is in progress to the Los Alamos Proton Storage Ring (PSR) to allow direct injection of the H^- beam into the ring and provide a beam bump system to move the circulating beam off the stripper foil. The primary benefits of this upgrade are matching the transverse phase space of the injected beam to the PSR acceptance and reduction of foil hits by the circulating beam by a factor of ten. Foil thickness is optimized to minimize the combination of circulating-beam losses plus losses due to excited H^0 states produced at injection. An overall factor of four reduction in losses is expected. The project comprises extensive modifications of the injection line, the injection section of the ring, and the waste-beam transport line. We will discuss the goals of the project, present an overview of the technical design, and describe the status of the implementation plan.

Firearm trigger assembly

DOEpatents

Crandall, David L.; Watson, Richard W.

2010-02-16

A firearm trigger assembly for use with a firearm includes a trigger mounted to a forestock of the firearm so that the trigger is movable between a rest position and a triggering position by a forwardly placed support hand of a user. An elongated trigger member operatively associated with the trigger operates a sear assembly of the firearm when the trigger is moved to the triggering position. An action release assembly operatively associated with the firearm trigger assembly and a movable assembly of the firearm prevents the trigger from being moved to the triggering position when the movable assembly is not in the locked position.

Electrical Engineering in Los Alamos Neutron Science Center Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Michael James

The field of electrical engineering plays a significant role in particle accelerator design and operations. Los Alamos National Laboratories LANSCE facility utilizes the electrical energy concepts of power distribution, plasma generation, radio frequency energy, electrostatic acceleration, signals and diagnostics. The culmination of these fields produces a machine of incredible potential with uses such as isotope production, neutron spallation, neutron imaging and particle analysis. The key isotope produced in LANSCE isotope production facility is Strontium-82 which is utilized for medical uses such as cancer treatment and positron emission tomography also known as PET scans. Neutron spallation is one of the verymore » few methods used to produce neutrons for scientific research the other methods are natural decay of transuranic elements from nuclear reactors. Accelerator produce neutrons by accelerating charged particles into neutron dense elements such as tungsten imparting a neutral particle with kinetic energy, this has the benefit of producing a large number of neutrons as well as minimizing the waste generated. Utilizing the accelerator scientist can gain an understanding of how various particles behave and interact with matter to better understand the natural laws of physics and the universe around us.« less

The performance of the upgraded Los Alamos Neutron Source

NASA Astrophysics Data System (ADS)

Ito, Takeyasu; LANL UCN Source Collaboration

2017-09-01

Los Alamos National Laboratory has been operating an ultracold (UCN) source based on a solid deuterium (SD2) UCN converter driven by spallation neutrons for over 10 years. It has recently been successfully upgraded, by replacing the cryostat that contains the cold neutron moderator, SD2 volume, and vertical UCN guide. The horizontal UCN guide that transports UCN out of the radiation shield was also replaced. The new design reflects lessons learned from the 10+ year long operation of the previous version of the UCN source and is optimized to maximize the cold neutron flux at the SD2 volume, featuring a close coupled cold neutron moderator, and maximize the transport of the UCN to experiments. During the commissioning of the upgraded UCN source, data were collected to measure its performance, including cold neutron spectra as a function of the cold moderator temperature, and the UCN density in a vessel outside the source. In this talk, after a brief overview of the design of the upgraded source, the results of the performance tests and comparison to prediction will be presented. This work was funded by LANL LDRD.

Portable propellant cutting assembly, and method of cutting propellant with assembly

NASA Technical Reports Server (NTRS)

Sharp, Roger A. (Inventor); Hoskins, Shawn W. (Inventor); Payne, Brett D. (Inventor)

2002-01-01

A propellant cutting assembly and method of using the assembly to cut samples of solid propellant in a repeatable and consistent manner is disclosed. The cutting assembly utilizes two parallel extension beams which are shorter than the diameter of a central bore of an annular solid propellant grain and can be loaded into the central bore. The assembly is equipped with retaining heads at its respective ends and an adjustment mechanism to position and wedge the assembly within the central bore. One end of the assembly is equipped with a cutting blade apparatus which can be extended beyond the end of the extension beams to cut into the solid propellant.

Atomistic Design and Simulations of Nanoscale Machines and Assembly

NASA Technical Reports Server (NTRS)

Goddard, William A., III; Cagin, Tahir; Walch, Stephen P.

2000-01-01

Over the three years of this project, we made significant progress on critical theoretical and computational issues in nanoscale science and technology, particularly in:(1) Fullerenes and nanotubes, (2) Characterization of surfaces of diamond and silicon for NEMS applications, (3) Nanoscale machine and assemblies, (4) Organic nanostructures and dendrimers, (5) Nanoscale confinement and nanotribology, (6) Dynamic response of nanoscale structures nanowires (metals, tubes, fullerenes), (7) Thermal transport in nanostructures.

PNNL Results from 2010 CALIBAN Criticality Accident Dosimeter Intercomparison Exercise

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, Robin L.; Conrady, Matthew M.

2011-10-28

This document reports the results of the Hanford personnel nuclear accident dosimeter (PNAD) and fixed nuclear accident dosimeter (FNAD) during a criticality accident dosimeter intercomparison exercise at the CEA Valduc Center on September 20-23, 2010. Pacific Northwest National Laboratory (PNNL) participated in a criticality accident dosimeter intercomparison exercise at the Commissariat a Energie Atomique (CEA) Valduc Center near Dijon, France on September 20-23, 2010. The intercomparison exercise was funded by the U.S. Department of Energy, Nuclear Criticality Safety Program, with Lawrence Livermore National Laboratory as the lead Laboratory. PNNL was one of six invited DOE Laboratory participants. The other participatingmore » Laboratories were: Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Savannah River Site (SRS), the Y-12 National Security Complex at Oak Ridge, and Sandia National Laboratory (SNL). The goals of PNNL's participation in the intercomparison exercise were to test and validate the procedures and algorithm currently used for the Hanford personnel nuclear accident dosimeters (PNADs) on the metallic reactor, CALIBAN, to test exposures to PNADs from the side and from behind a phantom, and to test PNADs that were taken from a historical batch of Hanford PNADs that had varying degrees of degradation of the bare indium foil. Similar testing of the PNADs was done on the Valduc SILENE test reactor in 2009 (Hill and Conrady, 2010). The CALIBAN results are reported here.« less

Multiple mechanisms of early plant community assembly with stochasticity driving the process.

PubMed

Marteinsdóttir, Bryndís; Svavarsdóttir, Kristín; Thórhallsdóttir, Thóra Ellen

2018-01-01

Initial plant establishment is one of the most critical phases in ecosystem development, where an early suite of physical (environmental filtering), biological (seed limitation, species interactions) and stochastic factors may affect successional trajectories and rates. While functional traits are commonly used to study processes that influence plant community assembly in late successional communities, few studies have applied them to primary succession. The objective here was to determine the importance of these factors in shaping early plant community assembly on a glacial outwash plain, Skeiðarársandur, in SE Iceland using a trait based approach. We used data on vascular plant assemblages at two different spatial scales (community and neighborhood) sampled in 2005 and 2012, and compiled a dataset on seven functional traits linked to species dispersal abilities, establishment, and persistence for all species within these assemblages. Trait-based null model analyses were used to determine the processes that influenced plant community assembly from the regional species pool into local communities, and to determine if the importance of these processes in community assembly was dependent on local environment or changed with time. On the community scale, for most traits, random processes dominated the assembly from the regional species pool. However, in some communities, there was evidence of non-random assembly in relation to traits linked to species dispersal abilities, persistence, and establishment. On the neighborhood scale, assembly was mostly random. The relative importance of different processes varied spatially and temporally and the variation was linked to local soil conditions. While stochasticity dominated assembly patterns of our early successional communities, there was evidence of both seed limitation and environmental filtering. Our results indicated that as soil conditions improved, environmental constraints on assembly became weaker and the

2016 Results for Avian Monitoring at the TA-36 Minie Site, TA-39 Point 6, and TA-16 Burn Ground at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hathcock, Charles Dean; Thompson, Brent E.; Berryhill, Jesse Tobias

Los Alamos National Security, LLC (LANS) biologists in the Environmental Compliance and Protection Division at Los Alamos National Laboratory (LANL) initiated a multi-year program in 2013 to monitor avifauna at two open detonation sites and one open burn site on LANL property. Monitoring results from these efforts are compared among years and with avifauna monitoring conducted at other areas across LANL. The objectives of this study are to determine whether LANL firing site operations impact bird abundance or diversity. LANS biologists completed the fourth year of this effort in 2016. The overall results from 2016 continue to indicate that operationsmore » are not negatively affecting bird populations. Data suggest that community structure may be changing at some sites and this trend will continue to be monitored.« less

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly

PubMed Central

Andreou, Andreas I.

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile—simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation. PMID:29293531

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly.

PubMed

Andreou, Andreas I; Nakayama, Naomi

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile-simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation.

Seal assembly

DOEpatents

Johnson, Roger Neal; Longfritz, William David

2001-01-01

A seal assembly that seals a gap formed by a groove comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove.

Dynamic Nanoparticles Assemblies

PubMed Central

WANG, LIBING; XU, LIGUANG; KUANG, HUA; XU, CHUANLAI; KOTOV, NICHOLAS A.

2012-01-01

CONSPECTUS Importance Although nanoparticle (NP) assemblies are at the beginning of their development, their unique geometrical shapes and media-responsive optical, electronic and magnetic properties have attracted significant interest. Nanoscale assembly bridges multiple sizes of materials: individual nanoparticles, discrete molecule-like or virus-like nanoscale agglomerates, microscale devices, and macroscale materials. The capacity to self-assemble can greatly facilitate the integration of nanotechnology with other technologies and, in particular, with microscale fabrication. In this Account, we describe developments in the emerging field of dynamic NP assemblies, which are spontaneously formed superstructures containing more than two inorganic nanoscale particles that display ability to change their geometrical, physical, chemical, and other attributes. In many ways, dynamic assemblies can represent a bottleneck in the ‘bottom-up’ fabrication of NP-based devices because they can produce a much greater variety of assemblies, but they also provide a convenient tool for variation of geometries and dimensions of nanoparticle assemblies. Classification Superstructures of NPs (and those held together by similar intrinsic forces) are classified into two groups: Class 1 where media and external fields can alter shape, conformation, and order of stable superstructures with a nearly constant number same. The future development of successful dynamic assemblies requires understanding the equilibrium in dynamic NP systems. The dynamic nature of Class 1 assemblies is associated with the equilibrium between different conformations of a superstructure and is comparable to the isomerization in classical chemistry. Class 2 assemblies involve the formation and/or breakage of linkages between the NPs, which is analogous to the classical chemical equilibrium for the formation of a molecule from atoms. Finer classification of NP assemblies in accord with established conventions

Safety Criticality Standards Using the French CRISTAL Code Package: Application to the AREVA NP UO{sub 2} Fuel Fabrication Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doucet, M.; Durant Terrasson, L.; Mouton, J.

2006-07-01

Criticality safety evaluations implement requirements to proof of sufficient sub critical margins outside of the reactor environment for example in fuel fabrication plants. Basic criticality data (i.e., criticality standards) are used in the determination of sub critical margins for all processes involving plutonium or enriched uranium. There are several criticality international standards, e.g., ARH-600, which is one the US nuclear industry relies on. The French Nuclear Safety Authority (DGSNR and its advising body IRSN) has requested AREVA NP to review the criticality standards used for the evaluation of its Low Enriched Uranium fuel fabrication plants with CRISTAL V0, the recentlymore » updated French criticality evaluation package. Criticality safety is a concern for every phase of the fabrication process including UF{sub 6} cylinder storage, UF{sub 6}-UO{sub 2} conversion, powder storage, pelletizing, rod loading, assembly fabrication, and assembly transportation. Until 2003, the accepted criticality standards were based on the French CEA work performed in the late seventies with the APOLLO1 cell/assembly computer code. APOLLO1 is a spectral code, used for evaluating the basic characteristics of fuel assemblies for reactor physics applications, which has been enhanced to perform criticality safety calculations. Throughout the years, CRISTAL, starting with APOLLO1 and MORET 3 (a 3D Monte Carlo code), has been improved to account for the growth of its qualification database and for increasing user requirements. Today, CRISTAL V0 is an up-to-date computational tool incorporating a modern basic microscopic cross section set based on JEF2.2 and the comprehensive APOLLO2 and MORET 4 codes. APOLLO2 is well suited for criticality standards calculations as it includes a sophisticated self shielding approach, a P{sub ij} flux determination, and a 1D transport (S{sub n}) process. CRISTAL V0 is the result of more than five years of development work focusing on

SM, TVIS Chassis Assembly, Treadmill Belt Assembly, Top

NASA Image and Video Library

2002-01-01

jsc2002e38738 (2002) --- Top view of the Treadmill Belt Assembly on the Treadmill Vibration Isolation System (TVIS) Chassis Assembly for use in the International Space Station (ISS) Service Module (SM).

Programmed Nanomaterial Assemblies in Large Scales: Applications of Synthetic and Genetically- Engineered Peptides to Bridge Nano-Assemblies and Macro-Assemblies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsui, Hiroshi

Work is reported in these areas: Large-scale & reconfigurable 3D structures of precise nanoparticle assemblies in self-assembled collagen peptide grids; Binary QD-Au NP 3D superlattices assembled with collagen-like peptides and energy transfer between QD and Au NP in 3D peptide frameworks; Catalytic peptides discovered by new hydrogel-based combinatorial phage display approach and their enzyme-mimicking 2D assembly; New autonomous motors of metal-organic frameworks (MOFs) powered by reorganization of self-assembled peptides at interfaces; Biomimetic assembly of proteins into microcapsules on oil-in-water droplets with structural reinforcement via biomolecular recognition-based cross-linking of surface peptides; and Biomimetic fabrication of strong freestanding genetically-engineered collagen peptide filmsmore » reinforced by quantum dot joints. We gained the broad knowledge about biomimetic material assembly from nanoscale to microscale ranges by coassembling peptides and NPs via biomolecular recognition. We discovered: Genetically-engineered collagen-like peptides can be self-assembled with Au NPs to generate 3D superlattices in large volumes (> μm{sup 3}); The assembly of the 3D peptide-Au NP superstructures is dynamic and the interparticle distance changes with assembly time as the reconfiguration of structure is triggered by pH change; QDs/NPs can be assembled with the peptide frameworks to generate 3D superlattices and these QDs/NPs can be electronically coupled for the efficient energy transfer; The controlled assembly of catalytic peptides mimicking the catalytic pocket of enzymes can catalyze chemical reactions with high selectivity; and, For the bacteria-mimicking swimmer fabrication, peptide-MOF superlattices can power translational and propellant motions by the reconfiguration of peptide assembly at the MOF-liquid interface.« less

Analysis of benchmark critical experiments with ENDF/B-VI data sets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hardy, J. Jr.; Kahler, A.C.

1991-12-31

Several clean critical experiments were analyzed with ENDF/B-VI data to assess the adequacy of the data for U{sup 235}, U{sup 238} and oxygen. These experiments were (1) a set of homogeneous U{sup 235}-H{sub 2}O assemblies spanning a wide range of hydrogen/uranium ratio, and (2) TRX-1, a simple, H{sub 2}O-moderated Bettis lattice of slightly-enriched uranium metal rods. The analyses used the Monte Carlo program RCP01, with explicit three-dimensional geometry and detailed representation of cross sections. For the homogeneous criticals, calculated k{sub crit} values for large, thermal assemblies show good agreement with experiment. This supports the evaluated thermal criticality parameters for U{supmore » 235}. However, for assemblies with smaller H/U ratios, k{sub crit} values increase significantly with increasing leakage and flux-spectrum hardness. These trends suggest that leakage is underpredicted and that the resonance eta of the ENDF/B-VI U{sup 235} is too large. For TRX-1, reasonably good agreement is found with measured lattice parameters (reaction-rate ratios). Of primary interest is rho28, the ratio of above-thermal to thermal U{sup 238} capture. Calculated rho28 is 2.3 ({+-} 1.7) % above measurement, suggesting that U{sup 238} resonance capture remains slightly overpredicted with ENDF/B-VI. However, agreement is better than observed with earlier versions of ENDF/B.« less

Lattice modeling and application of independent component analysis to high power, long bunch beams in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Kolski, Jeffrey

The linear lattice properties of the Proton Storage Ring (PSR) at the Los Alamos Neutron Science Center (LANSCE) in Los Alamos, NM were measured and applied to determine a better linear accelerator model. We found that the initial model was deficient in predicting the vertical focusing strength. The additional vertical focusing was located through fundamental understanding of experiment and statistically rigorous analysis. An improved model was constructed and compared against the initial model and measurement at operation set points and set points far away from nominal and was shown to indeed be an enhanced model. Independent component analysis (ICA) is a tool for data mining in many fields of science. Traditionally, ICA is applied to turn-by-turn beam position data as a means to measure the lattice functions of the real machine. Due to the diagnostic setup for the PSR, this method is not applicable. A new application method for ICA is derived, ICA applied along the length of the bunch. The ICA modes represent motions within the beam pulse. Several of the dominate ICA modes are experimentally identified.

Stormwater Pollution Prevention Plan for the TA-03-22 Power and Steam Plant, Los Alamos National Laboratory, Revision 3, January 2018

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgin, Jillian Elizabeth

This Storm Water Pollution Prevention Plan (SWPPP) was developed in accordance with the provisions of the Clean Water Act (33 U.S.C. §§1251 et seq., as amended), and the Multi-Sector General Permit for Storm Water Discharges Associated with Industrial Activity (U.S. EPA, June 2015) issued by the U.S. Environmental Protection Agency (EPA) for the National Pollutant Discharge Elimination System (NPDES) and using the industry specific permit requirements for Sector O-Steam Electric Generating Facilities as a guide. This SWPPP applies to discharges of stormwater from the operational areas of the TA-03-22 Power and Steam Plant at Los Alamos National Laboratory. Los Alamosmore » National Laboratory (also referred to as LANL or the “Laboratory”) is owned by the Department of Energy (DOE), and is operated by Los Alamos National Security, LLC (LANS). Throughout this document, the term “facility” refers to the TA-03-22 Power and Steam Plant and associated areas. The current permit expires at midnight on June 4, 2020.« less

The Los Alamos Seismic Network (LASN): Improved Network Instrumentation, Local Earthquake Catalog Updates, and Peculiar Types of Data

NASA Astrophysics Data System (ADS)

Roberts, P. M.; Ten Cate, J. A.; House, L. S.; Greene, M. K.; Morton, E.; Kelley, R. E.

2013-12-01

The Los Alamos Seismic Network (LASN) has operated for 41 years, and provided the data to locate more than 2,500 earthquakes in north-central New Mexico. The network was installed for seismic verification research, as well as to monitor and locate earthquakes near Los Alamos National Laboratory (LANL). LASN stations are the only monitoring stations in New Mexico north of Albuquerque. The original network once included 22 stations in northern Mew Mexico. With limited funding in the early 1980's, the network was downsized to 7 stations within an area of about 15 km (N-S) by 15 km (E-W), centered on Los Alamos. Over the last four years, eight additional stations have been installed, which have considerably expanded the spatial coverage of the network. Currently, 7 stations have broadband, three-component seismometers with digital telemetry, and the remaining 8 have traditional 1 Hz short-period seismometers with either analog telemetry or on-site digital recording. A vertical array of accelerometers was also installed in a wellbore on LANL property. This borehole array has 3-component digital strong-motion sensors. Recently we began upgrading the local strong-motion accelerometer (SMA) network as well, with the addition of high-resolution digitizers and high-sensitivity force-balance accelerometers (FBA). We will present an updated description of the current LASN station, instrumentation and telemetry configurations, as well as the data acquisition and event-detection software structure used to record events in Earthworm. Although more than 2,000 earthquakes were detected and located in north-central New Mexico during the first 11 years of LASN's operation (1973 to 1984), currently only 1-2 earthquakes per month are detected and located within about 150 km of Los Alamos. Over 850 of these nearby earthquakes have been located from 1973 to present. We recently updated the LASN earthquake catalog for north-central New Mexico up through 2012 and most of 2013. Locations

Comparison of three assembly strategies for a heterozygous seedless grapevine genome assembly.

PubMed

Patel, Sagar; Lu, Zhixiu; Jin, Xiaozhu; Swaminathan, Padmapriya; Zeng, Erliang; Fennell, Anne Y

2018-01-17

De novo heterozygous assembly is an ongoing challenge requiring improved assembly approaches. In this study, three strategies were used to develop de novo Vitis vinifera 'Sultanina' genome assemblies for comparison with the inbred V. vinifera (PN40024 12X.v2) reference genome and a published Sultanina ALLPATHS-LG assembly (AP). The strategies were: 1) a default PLATANUS assembly (PLAT_d) for direct comparison with AP assembly, 2) an iterative merging strategy using METASSEMBLER to combine PLAT_d and AP assemblies (MERGE) and 3) PLATANUS parameter modifications plus GapCloser (PLAT*_GC). The three new assemblies were greater in size than the AP assembly. PLAT*_GC had the greatest number of scaffolds aligning with a minimum of 95% identity and ≥1000 bp alignment length to V. vinifera (PN40024 12X.v2) reference genome. SNP analysis also identified additional high quality SNPs. A greater number of sequence reads mapped back with zero-mismatch to the PLAT_d, MERGE, and PLAT*_GC (>94%) than was found in the AP assembly (87%) indicating a greater fidelity to the original sequence data in the new assemblies than in AP assembly. A de novo gene prediction conducted using seedless RNA-seq data predicted > 30,000 coding sequences for the three new de novo assemblies, with the greatest number (30,544) in PLAT*_GC and only 26,515 for the AP assembly. Transcription factor analysis indicated good family coverage, but some genes found in the VCOST.v3 annotation were not identified in any of the de novo assemblies, particularly some from  the MYB and ERF families. The PLAT_d and PLAT*_GC had a greater number of synteny blocks with the V. vinifera (PN40024 12X.v2) reference genome than AP or MERGE. PLAT*_GC provided the most contiguous assembly with only 1.2% scaffold N, in contrast to AP (10.7% N), PLAT_d (6.6% N) and Merge (6.4% N). A PLAT*_GC pseudo-chromosome assembly with chromosome alignment to the reference genome V. vinifera, (PN40024 12X.v2) provides new information

New self-assembly strategies for next generation lithography

NASA Astrophysics Data System (ADS)

Schwartz, Evan L.; Bosworth, Joan K.; Paik, Marvin Y.; Ober, Christopher K.

2010-04-01

Future demands of the semiconductor industry call for robust patterning strategies for critical dimensions below twenty nanometers. The self assembly of block copolymers stands out as a promising, potentially lower cost alternative to other technologies such as e-beam or nanoimprint lithography. One approach is to use block copolymers that can be lithographically patterned by incorporating a negative-tone photoresist as the majority (matrix) phase of the block copolymer, paired with photoacid generator and a crosslinker moiety. In this system, poly(α-methylstyrene-block-hydroxystyrene)(PαMS-b-PHOST), the block copolymer is spin-coated as a thin film, processed to a desired microdomain orientation with long-range order, and then photopatterned. Therefore, selfassembly of the block copolymer only occurs in select areas due to the crosslinking of the matrix phase, and the minority phase polymer can be removed to produce a nanoporous template. Using bulk TEM analysis, we demonstrate how the critical dimension of this block copolymer is shown to scale with polymer molecular weight using a simple power law relation. Enthalpic interactions such as hydrogen bonding are used to blend inorganic additives in order to enhance the etch resistance of the PHOST block. We demonstrate how lithographically patternable block copolymers might fit in to future processing strategies to produce etch-resistant self-assembled features at length scales impossible with conventional lithography.

Biomimetic Layer-by-Layer Self-Assembly of Nanofilms, Nanocoatings, and 3D Scaffolds for Tissue Engineering.

PubMed

Zhang, Shichao; Xing, Malcolm; Li, Bingyun

2018-06-01

Achieving surface design and control of biomaterial scaffolds with nanometer- or micrometer-scaled functional films is critical to mimic the unique features of native extracellular matrices, which has significant technological implications for tissue engineering including cell-seeded scaffolds, microbioreactors, cell assembly, tissue regeneration, etc. Compared with other techniques available for surface design, layer-by-layer (LbL) self-assembly technology has attracted extensive attention because of its integrated features of simplicity, versatility, and nanoscale control. Here we present a brief overview of current state-of-the-art research related to the LbL self-assembly technique and its assembled biomaterials as scaffolds for tissue engineering. An overview of the LbL self-assembly technique, with a focus on issues associated with distinct routes and driving forces of self-assembly, is described briefly. Then, we highlight the controllable fabrication, properties, and applications of LbL self-assembly biomaterials in the forms of multilayer nanofilms, scaffold nanocoatings, and three-dimensional scaffolds to systematically demonstrate advances in LbL self-assembly in the field of tissue engineering. LbL self-assembly not only provides advances for molecular deposition but also opens avenues for the design and development of innovative biomaterials for tissue engineering.

Self-assembly of peptide-amphiphile nanofibers: the roles of hydrogen bonding and amphiphilic packing.

PubMed

Paramonov, Sergey E; Jun, Ho-Wook; Hartgerink, Jeffrey D

2006-06-07

The role of hydrogen bonding and amphiphilic packing in the self-assembly of peptide-amphiphiles (PAs) was investigated using a series of 26 PA derivatives, including 19 N-methylated variants and 7 alanine mutants. These were studied by circular dichroism spectroscopy, a variety of Fourier transform infrared spectroscopies, rheology, and vitreous ice cryo-transmission electron microscopy. From these studies, we have been able to determine which amino acids are critical for the self-assembly of PAs into nanofibers, why the nanofiber is favored over other possible nanostructures, the orientation of hydrogen bonding with respect to the nanofiber axis, and the constraints placed upon the portion of the peptide most intimately associated with the biological environment. Furthermore, by selectively eliminating key hydrogen bonds, we are able to completely change the nanostructure resulting from self-assembly in addition to modifying the macroscopic mechanical properties associated with the assembled gel. This study helps to clarify the mechanism of self-assembly for peptide amphiphiles and will thereby help in the design of future generations of PAs.

Fuel injection assembly for use in turbine engines and method of assembling same

DOEpatents

Uhm, Jong Ho; Johnson, Thomas Edward

2015-03-24

A fuel injection assembly for use in a turbine engine is provided. The fuel injection assembly includes a plurality of tube assemblies, wherein each of the tube assemblies includes an upstream portion and a downstream portion. Each tube assembly includes a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid through the tube assembly to facilitate reducing a temperature therein.

Population array and agricultural data arrays for the Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, K.W.; Duffy, S.; Kowalewsky, K.

1998-07-01

To quantify or estimate the environmental and radiological impacts from man-made sources of radioactive effluents, certain dose assessment procedures were developed by various government and regulatory agencies. Some of these procedures encourage the use of computer simulations (models) to calculate air dispersion, environmental transport, and subsequent human exposure to radioactivity. Such assessment procedures are frequently used to demonstrate compliance with Department of Energy (DOE) and US Environmental Protection Agency (USEPA) regulations. Knowledge of the density and distribution of the population surrounding a source is an essential component in assessing the impacts from radioactive effluents. Also, as an aid to calculatingmore » the dose to a given population, agricultural data relevant to the dose assessment procedure (or computer model) are often required. This report provides such population and agricultural data for the area surrounding Los Alamos National Laboratory.« less

Water droplets as template for next-generation self-assembled poly-(etheretherketone) with cardo membranes.

PubMed

Gugliuzza, Annarosa; Aceto, Marianna Carmela; Macedonio, Francesca; Drioli, Enrico

2008-08-28

Next generation PEEK-WC membranes have been fabricated by using an innovative self-assembly technique. Patterned architectures have been achieved via a solvent-reduced and water-assisted process, resulting in honeycomb packed geometry. The membranes exhibit monodisperse pores with size and shape comparable to those left by templating water droplets. Influencing factors for the formation of self-assembled poly-(etheretherketone) with Cardo [PEEK-WC] membranes have been evaluated, identifying the critical parameters for nucleation, growth, and propagation of the droplet-mobile arrays through the overall films. Structure-transport relationships have been discussed according to the results achieved from the implementation of membrane distillation processes, yielding indication about the suitability of self-assembled PEEK-WC films to work as interfaces in contactor operations.

The mechanics and design of a lightweight three-dimensional graphene assembly

PubMed Central

Qin, Zhao; Jung, Gang Seob; Kang, Min Jeong; Buehler, Markus J.

2017-01-01

Recent advances in three-dimensional (3D) graphene assembly have shown how we can make solid porous materials that are lighter than air. It is plausible that these solid materials can be mechanically strong enough for applications under extreme conditions, such as being a substitute for helium in filling up an unpowered flight balloon. However, knowledge of the elastic modulus and strength of the porous graphene assembly as functions of its structure has not been available, preventing evaluation of its feasibility. We combine bottom-up computational modeling with experiments based on 3D-printed models to investigate the mechanics of porous 3D graphene materials, resulting in new designs of carbon materials. Our study reveals that although the 3D graphene assembly has an exceptionally high strength at relatively high density (given the fact that it has a density of 4.6% that of mild steel and is 10 times as strong as mild steel), its mechanical properties decrease with density much faster than those of polymer foams. Our results provide critical densities below which the 3D graphene assembly starts to lose its mechanical advantage over most polymeric cellular materials. PMID:28070559

VITRIFICATION SYSTEM FOR THE TREATMENT OF PLUTONIUM-BEARING WASTE AT LOS ALAMOS NATIONAL LABORATORY

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. NAKAOKA; G. VEAZEY; ET AL

2001-05-01

A glove box vitrification system is being fabricated to process aqueous evaporator bottom waste generated at the Plutonium Facility (TA-55) at Los Alamos National Laboratory (LANL). The system will be the first within the U.S. Department of Energy Complex to routinely convert Pu{sup 239}-bearing transuranic (TRU) waste to a glass matrix for eventual disposal at the Waste Isolation Pilot Plant (WIPP). Currently at LANL, this waste is solidified in Portland cement. Radionuclide loading in the cementation process is restricted by potential radiolytic degradation (expressed as a wattage limit), which has been imposed to prevent the accumulation of flammable concentrations ofmore » H{sub 2} within waste packages. Waste matrixes with a higher water content (e.g., cement) are assigned a lower permissible wattage limit to compensate for their potential higher generation of H{sub 2}. This significantly increases the number of waste packages that must be prepared and shipped, thus driving up the costs of waste handling and disposal. The glove box vitrification system that is under construction will address this limitation. Because the resultant glass matrix produced by the vitrification process is non-hydrogenous, no H{sub 2} can be radiolytically evolved, and drums could be loaded to the maximum allowable limit of 40 watts. In effect, the glass waste form shifts the limiting constraint for loading disposal drums from wattage to the criticality limit of 200 fissile gram equivalents, thus significantly reducing the number of drums generated from this waste stream. It is anticipated that the number of drums generated from treatment of evaporator bottoms will be reduced by a factor of 4 annually when the vitrification system is operational. The system is currently undergoing non-radioactive operability testing, and will be fully operational in the year 2003.« less

User Guide for the Plotting Software for the Los Alamos National Laboratory Nuclear Weapons Analysis Tools Version 2.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleland, Timothy James

The Los Alamos National Laboratory Plotting Software for the Nuclear Weapons Analysis Tools is a Java™ application based upon the open source library JFreeChart. The software provides a capability for plotting data on graphs with a rich variety of display options while allowing the viewer interaction via graph manipulation and scaling to best view the data. The graph types include XY plots, Date XY plots, Bar plots and Histogram plots.

The First Thirty-six Years: A History of the Albuquerque District, 1935-1971

DTIC Science & Technology

1973-01-01

rights of American citizens in the nation’s history . ZIA PROJECT LOS ALAMOS RANCH SCHOOL, FULLER LODGE Late in 1938 German scientists discovered that...explosive components of the atomic bomb were loaded into the rear seat of a sedan at Los Alamos for the journey to Trinity . Further assembly and tests of...TYPE 3. DATES COVERED 00-00-1973 to 00-00-1973 4. TITLE AND SUBTITLE The First Thirty-six Years : A History of the Albuquerque District, 1935

Criticality assessment of LLRWDF closure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarrack, A.G.; Weber, J.H.; Woody, N.D.

1992-10-06

During the operation of the Low Level Radioactive Waste Disposal Facility (LLRWDF), large amounts (greater than 100 kg) of enriched uranium (EU) were buried. This EU came primarily from the closing and decontamination of the Naval Fuels Facility in the time period from 1987--1989. Waste Management Operations (WMO) procedures were used to keep the EU boxes separated to prevent possible criticality during normal operation. Closure of the LLRWDF is currently being planned, and waste stabilization by Dynamic Compaction (DC) is proposed. Dynamic compaction will crush the containers in the LLRWDF and result in changes in their geometry. Research of themore » LLRWDF operations and record keeping practices have shown that the EU contents of trenches are known, but details of the arrangement of the contents cannot be proven. Reviews of the trench contents, combined with analysis of potential critical configurations, revealed that some portions of the LLRWDF can be expected to be free of criticality concerns while other sections have credible probabilities for the assembly of a critical mass, even in the uncompacted configuration. This will have an impact on the closure options and which trenches can be compacted.« less

Role of Surface Charge Density in Nanoparticle-templated Assembly of Bromovirus Protein Cages

PubMed Central

Daniel, Marie-Christine; Tsvetkova, Irina B.; Quinkert, Zachary T.; Murali, Ayaluru; De, Mrinmoy; Rotello, Vincent M.; Kao, C. Cheng; Dragnea, Bogdan

2010-01-01

Self-assembling icosahedral protein cages have potencially useful physical and chemical characteristics for a variety of nanotechnology applications, ranging from therapeutic or diagnostic vectors to building blocks for hierarchical materials. For application-specific functional control of protein cage assemblies, a deeper understanding of the interaction between the protein cage and its payload is necessary. Protein-cage encapsulated nanoparticles, with their well-defined surface chemistry, allow for systematic control over key parameters of encapsulation such as the surface charge, hydrophobicity, and size. Independent control over these variables allows experimental testing of different assembly mechanism models. Previous studies done with Brome mosaic virus capsids and negatively-charged gold nanoparticles indicated that the result of the self-assembly process depends on the diameter of the particle. However, in these experiments, the surface-ligand density was maintained at saturation levels, while the total charge and the radius of curvature remained coupled variables, making the interpretation of the observed dependence on the core size difficult. The current work furnishes evidence of a critical surface charge density for assembly through an analysis aimed at decoupling the surface charge the core size. PMID:20575505

The Mammalian Cell Cycle Regulates Parvovirus Nuclear Capsid Assembly

PubMed Central

Riolobos, Laura; Domínguez, Carlos; Kann, Michael; Almendral, José M.

2015-01-01

It is unknown whether the mammalian cell cycle could impact the assembly of viruses maturing in the nucleus. We addressed this question using MVM, a reference member of the icosahedral ssDNA nuclear parvoviruses, which requires cell proliferation to infect by mechanisms partly understood. Constitutively expressed MVM capsid subunits (VPs) accumulated in the cytoplasm of mouse and human fibroblasts synchronized at G0, G1, and G1/S transition. Upon arrest release, VPs translocated to the nucleus as cells entered S phase, at efficiencies relying on cell origin and arrest method, and immediately assembled into capsids. In synchronously infected cells, the consecutive virus life cycle steps (gene expression, proteins nuclear translocation, capsid assembly, genome replication and encapsidation) proceeded tightly coupled to cell cycle progression from G0/G1 through S into G2 phase. However, a DNA synthesis stress caused by thymidine irreversibly disrupted virus life cycle, as VPs became increasingly retained in the cytoplasm hours post-stress, forming empty capsids in mouse fibroblasts, thereby impairing encapsidation of the nuclear viral DNA replicative intermediates. Synchronously infected cells subjected to density-arrest signals while traversing early S phase also blocked VPs transport, resulting in a similar misplaced cytoplasmic capsid assembly in mouse fibroblasts. In contrast, thymidine and density arrest signals deregulating virus assembly neither perturbed nuclear translocation of the NS1 protein nor viral genome replication occurring under S/G2 cycle arrest. An underlying mechanism of cell cycle control was identified in the nuclear translocation of phosphorylated VPs trimeric assembly intermediates, which accessed a non-conserved route distinct from the importin α2/β1 and transportin pathways. The exquisite cell cycle-dependence of parvovirus nuclear capsid assembly conforms a novel paradigm of time and functional coupling between cellular and virus life

Drosophila TRP and TRPL are assembled as homomultimeric channels in vivo

PubMed Central

Katz, Ben; Oberacker, Tina; Richter, David; Tzadok, Hanan; Peters, Maximilian; Minke, Baruch; Huber, Armin

2013-01-01

Summary Family members of the cationic transient receptor potential (TRP) channels serve as sensors and transducers of environmental stimuli. The ability of different TRP channel isoforms of specific subfamilies to form heteromultimers and the structural requirements for channel assembly are still unresolved. Although heteromultimerization of different mammalian TRP channels within single subfamilies has been described, even within a subfamily (such as TRPC) not all members co-assemble with each other. In Drosophila photoreceptors two TRPC channels, TRP and TRP-like protein (TRPL) are expressed together in photoreceptors where they generate the light-induced current. The formation of functional TRP–TRPL heteromultimers in cell culture and in vitro has been reported. However, functional in vivo assays have shown that each channel functions independently of the other. Therefore, the issue of whether TRP and TRPL form heteromultimers in vivo is still unclear. In the present study we investigated the ability of TRP and TRPL to form heteromultimers, and the structural requirements for channel assembly, by studying assembly of GFP-tagged TRP and TRPL channels and chimeric TRP and TRPL channels, in vivo. Interaction studies of tagged and native channels as well as native and chimeric TRP–TRPL channels using co-immunoprecipitation, immunocytochemistry and electrophysiology, critically tested the ability of TRP and TRPL to interact. We found that TRP and TRPL assemble exclusively as homomultimeric channels in their native environment. The above analyses revealed that the transmembrane regions of TRP and TRPL do not determine assemble specificity of these channels. However, the C-terminal regions of both TRP and TRPL predominantly specify the assembly of homomeric TRP and TRPL channels. PMID:23687378

Drosophila TRP and TRPL are assembled as homomultimeric channels in vivo.

PubMed

Katz, Ben; Oberacker, Tina; Richter, David; Tzadok, Hanan; Peters, Maximilian; Minke, Baruch; Huber, Armin

2013-07-15

Family members of the cationic transient receptor potential (TRP) channels serve as sensors and transducers of environmental stimuli. The ability of different TRP channel isoforms of specific subfamilies to form heteromultimers and the structural requirements for channel assembly are still unresolved. Although heteromultimerization of different mammalian TRP channels within single subfamilies has been described, even within a subfamily (such as TRPC) not all members co-assemble with each other. In Drosophila photoreceptors two TRPC channels, TRP and TRP-like protein (TRPL) are expressed together in photoreceptors where they generate the light-induced current. The formation of functional TRP-TRPL heteromultimers in cell culture and in vitro has been reported. However, functional in vivo assays have shown that each channel functions independently of the other. Therefore, the issue of whether TRP and TRPL form heteromultimers in vivo is still unclear. In the present study we investigated the ability of TRP and TRPL to form heteromultimers, and the structural requirements for channel assembly, by studying assembly of GFP-tagged TRP and TRPL channels and chimeric TRP and TRPL channels, in vivo. Interaction studies of tagged and native channels as well as native and chimeric TRP-TRPL channels using co-immunoprecipitation, immunocytochemistry and electrophysiology, critically tested the ability of TRP and TRPL to interact. We found that TRP and TRPL assemble exclusively as homomultimeric channels in their native environment. The above analyses revealed that the transmembrane regions of TRP and TRPL do not determine assemble specificity of these channels. However, the C-terminal regions of both TRP and TRPL predominantly specify the assembly of homomeric TRP and TRPL channels.

Fuel injection assembly for use in turbine engines and method of assembling same

DOEpatents

Berry, Jonathan Dwight; Johnson, Thomas Edward; York, William David; Uhm, Jong Ho

2015-12-15

A fuel injection assembly for use in a turbine engine is provided. The fuel injection assembly includes an end cover, an endcap assembly, a fluid supply chamber, and a plurality of tube assemblies positioned at the endcap assembly. Each of the tube assemblies includes housing having a fuel plenum and a cooling fluid plenum. The cooling fluid plenum is positioned downstream from the fuel plenum and separated from the fuel plenum by an intermediate wall. The plurality of tube assemblies also include a plurality of tubes that extends through the housing. Each of the plurality of tubes is coupled in flow communication with the fluid supply chamber and a combustion chamber positioned downstream from the tube assembly. The plurality of tube assemblies further includes an aft plate at a downstream end of the cooling fluid plenum. The plate includes at least one aperture.

AutoAssemblyD: a graphical user interface system for several genome assemblers.

PubMed

Veras, Adonney Allan de Oliveira; de Sá, Pablo Henrique Caracciolo Gomes; Azevedo, Vasco; Silva, Artur; Ramos, Rommel Thiago Jucá

2013-01-01

Next-generation sequencing technologies have increased the amount of biological data generated. Thus, bioinformatics has become important because new methods and algorithms are necessary to manipulate and process such data. However, certain challenges have emerged, such as genome assembly using short reads and high-throughput platforms. In this context, several algorithms have been developed, such as Velvet, Abyss, Euler-SR, Mira, Edna, Maq, SHRiMP, Newbler, ALLPATHS, Bowtie and BWA. However, most such assemblers do not have a graphical interface, which makes their use difficult for users without computing experience given the complexity of the assembler syntax. Thus, to make the operation of such assemblers accessible to users without a computing background, we developed AutoAssemblyD, which is a graphical tool for genome assembly submission and remote management by multiple assemblers through XML templates. AssemblyD is freely available at https://sourceforge.net/projects/autoassemblyd. It requires Sun jdk 6 or higher.

Self Assembled Particles

NASA Technical Reports Server (NTRS)

Palacci, Jeremie (Inventor); Pine, David J. (Inventor); Chaikin, Paul Michael (Inventor); Sacanna, Stefano (Inventor)

2017-01-01

A self-assembling structure using non-equilibrium driving forces leading to 'living crystals' and other maniputable particles with a complex dynamics. The dynamic self-assembly assembly results from a competition between self-propulsion of particles and an attractive interaction between the particles. As a result of non-equilibrium driving forces, the crystals form, grow, collide, anneal, repair themselves and spontaneously self-destruct, thereby enabling reconfiguration and assembly to achieve a desired property.

Probe tip heating assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmitz, Roger William; Oh, Yunje

A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably receivedmore » and clamped within the socket.« less

The Teaching of Critical Thinking Skills by Academic Librarians.

ERIC Educational Resources Information Center

Goetzfridt, Nicholas J.

Teaching critical thinking is a relatively new dimension of bibliographic instruction (BI) in the academic environment. It marks a departure from the teaching of "user skills" in which the primary concern is enabling library patrons to determine the appropriateness of reference tools and to use those tools effectively. This report assembles a…

Explosively driven two-shockwave tools with application to ejecta formation at the Los Alamos National Laboratory Proton Radiography Facility

NASA Astrophysics Data System (ADS)

Buttler, William

2013-06-01

We present the development of an explosively driven physics tool to generate two mostly uniaxial shockwaves. The tool is being used to extend single shockwave ejecta models to a subsequent shockwave event separated by a time interval on the order of a few microseconds. We explore the possibility of varying the amplitude of both the first and second shockwaves, and we apply the tool in experimental geometries on Sn with a surface roughness of Ra = 0 . 8 μ m. We then evaluate the tool further at the Los Alamos National Laboratory Proton Radiography (pRad) Facility in an application to Sn with larger scale perturbations of wavelength 550 μ m, and various amplitudes that gave wave-number amplitude products of η0 2 π / λ = { 3 / 4 , 1 / 2 , 1 / 4 , 1 / 8 } , where the perturbation amplitude is η0, and the wave-number k = 2 π / λ . The pRad data and velocimetry imply it should be possible to develop a second shock ejecta model based on unstable Richtmyer-Meshkov physics. In collaboration with David Oro, Fesseha Mariam, Alexander Saunders, Malcolm Andrews, Frank Cherne, James Hammerberg. Robert Hixson, Christopher Morris, Russell Olson, Dean Preston, Joseph Stone, Dale Tupa, and Wendy Vogan-McNeil, Los Alamos National Laboratory,

High-Rate Assembly of Nanomaterials on Insulating Surfaces Using Electro-Fluidic Directed Assembly.

PubMed

Yilmaz, Cihan; Sirman, Asli; Halder, Aditi; Busnaina, Ahmed

2017-08-22

Conductive or semiconducting nanomaterials-based applications such as electronics and sensors often require direct placement of such nanomaterials on insulating surfaces. Most fluidic-based directed assembly techniques on insulating surfaces utilize capillary force and evaporation but are diffusion limited and slow. Electrophoretic-based assembly, on the other hand, is fast but can only be utilized for assembly on a conductive surface. Here, we present a directed assembly technique that enables rapid assembly of nanomaterials on insulating surfaces. The approach leverages and combines fluidic and electrophoretic assembly by applying the electric field through an insulating surface via a conductive film underneath. The approach (called electro-fluidic) yields an assembly process that is 2 orders of magnitude faster compared to fluidic assembly. By understanding the forces on the assembly process, we have demonstrated the controlled assembly of various types of nanomaterials that are conducting, semiconducting, and insulating including nanoparticles and single-walled carbon nanotubes on insulating rigid and flexible substrates. The presented approach shows great promise for making practical devices in miniaturized sensors and flexible electronics.

A method for development of efficient 3D models for neutronic calculations of ASTRA critical facility using experimental information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balanin, A. L.; Boyarinov, V. F.; Glushkov, E. S.

The application of experimental information on measured axial distributions of fission reaction rates for development of 3D numerical models of the ASTRA critical facility taking into account azimuthal asymmetry of the assembly simulating a HTGR with annular core is substantiated. Owing to the presence of the bottom reflector and the absence of the top reflector, the application of 2D models based on experimentally determined buckling is impossible for calculation of critical assemblies of the ASTRA facility; therefore, an alternative approach based on the application of the extrapolated assembly height is proposed. This approach is exemplified by the numerical analysis ofmore » experiments on measurement of efficiency of control rods mockups and protection system (CPS).« less

Drive piston assembly for a valve actuator assembly

DOEpatents

Sun, Zongxuan

2010-02-23

A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

Microfluidic assembly blocks.

PubMed

Rhee, Minsoung; Burns, Mark A

2008-08-01

An assembly approach for microdevice construction using prefabricated microfluidic components is presented. Although microfluidic systems are convenient platforms for biological assays, their use in the life sciences is still limited mainly due to the high-level fabrication expertise required for construction. This approach involves prefabrication of individual microfluidic assembly blocks (MABs) in PDMS that can be readily assembled to form microfluidic systems. Non-expert users can assemble the blocks on glass slides to build their devices in minutes without any fabrication steps. In this paper, we describe the construction and assembly of the devices using the MAB methodology, and demonstrate common microfluidic applications including laminar flow development, valve control, and cell culture.

Storm Water Quality in Los Alamos Canyon following the Cerro Grande Fire

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Johansen; B. Enz; B. Gallaher

In May 2000, the Cerro Grande Fire burned about 7400 acres of forest on the Los Alamos National Laboratory (LANL) and about 10,000 acres in watersheds above LANL on Santa Fe National Forest lands. The resulting burned landscapes raised concerns of increased storm water runoff and transport of contaminants by runoff in the canyons traversing LANL. On June 2 and 3, 2000, rain fell in the Los Alamos Canyon watershed generating storm water runoff in the canyon bottom. This event was important in that it was the first significant runoff on LANL following the fire and occurred in a canyonmore » containing known legacy waste sites. Samples from this runoff were analyzed for radionuclide, metal, inorganic, and organic constituents. Results show radionuclide concentrations at or below previous (pre-fire) maximum levels at locations on LANL and downstream. However, greater concentrations of some fallout-associated radionuclides (cesium-137 and strontium-90) were seen arriving on LANL from upstream areas compared to pre-fire conditions. Tests indicate most of the radionuclides in the samples were bound to sediments, not dissolved in water. Most radionuclide concentrations in sediments were below LANL Screening Action Levels, with cesium-137 and strontium-90 as exceptions. Most radionuclide concentrations in samples taken at LANL's downstream boundary were greater than those taken upstream, indicating the presence of contributing sources on LANL. For comparison purposes, doses were calculated on a mrem per liter of unfiltered water basis for 11 radionuclides commonly associated with atmospheric fallout and with LANL operations. The maximum dose was 0.094 mrem per liter unfiltered water and was largely associated with plutonium-239/240. In contrast, all filtered samples had total doses less than 0.001 mrem per liter. Compared to past data, potential doses were not increased by the fire during this initial runoff event. Of the 25 metals tested for, seven were above pre

University of New Mexico-Los Alamos National Laboratory Program in Volcanology

NASA Astrophysics Data System (ADS)

Goff, F.; Fischer, T.; Baldridge, W.; Wohletz, K.; Smith, G.; Heiken, G.; Valentine, G.; Elston, W.

2002-05-01

The UNM-LANL Program in Volcanology was a vision of Wolf Elston in the late 1980s. Finally established in mid-1992, the program takes advantage of the extensive volcanic record preserved in northern New Mexico, and of the unique expertise and exceptional research facilities existing at the two institutions. Courses are directed toward upper division and graduate level students. The Los Alamos participants are adjunct professors and they take an active role in creating courses, advising thesis candidates, and providing research support. The curriculum is flexible but has a core upper division class in Physical Volcanology. Other classes offered in various years have included Volcanology and Human Affairs; Magmatic and Geothermal Systems; Tectonics and Magma Generation; Volcanoes of North America; Instrumentation for Volcanology; and Advanced Igneous Petrology. Perhaps the most renowned class in the program is the Volcanology Summer Field Course offered in even numbered years. This 3.5-week class is based in the Jemez Mountains volcanic field, which contains the famous Valles caldera (1.2 Ma to 50 ka). All types of calc-alkaline to alkalic domes, flows, tuffs, and intrusions, plus derivative sediments, mineralized zones, and thermal fluids are available for instructional purposes. Students are required to complete nine rigorous field exercises starting with basic instruction in pyroclastic fall, flow, and surge, then progressing towards hydrothermally altered, intracaldera resurgent dome and moat deposits in an active hot spring and fumarole system. The class is open to graduate students, advanced undergraduates, and private sector employees with special needs. Enrollment is competitive with limited financial support and limited space for 17 students. Evening lectures, study time, lodging, and meals are provided at the UNM-owned Young's Ranch built in the 1920s, nestled in a canyon flanked by orange cliffs of Bandelier Tuff. About 120 students from 12 countries have

Autonomous Assembly of Modular Structures in Space and on Extraterrestrial Locations

NASA Technical Reports Server (NTRS)

Alhorn, Dean C.

2005-01-01

the number of integrity sensors will be significant. Thus simple, low cost sensors are integral to the success of this concept. This paper will address these issues and will propose a novel concept for assembling space structures autonomously. The paper will present Several autonomous assembly methods. Core technologies required to achieve in space assembly will be discussed and novel techniques for communicating, sensing, docking and assembly will be detailed. These core technologies are critical to the goal of utilizing space in a cost efficient and safe manner. Finally, these technologies can also be applied to other systems both on earth and extraterrestrial environments.

Wider pulsation instability regions for β Cephei and SPB stars calculated using new Los Alamos opacities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walczak, Przemysław; Fontes, Christopher John; Colgan, James Patrick

Here, our goal is to test the newly developed OPLIB opacity tables from Los Alamos National Laboratory and check their influence on the pulsation properties of B-type stars. We calculated models using MESA and Dziembowski codes for stellar evolution and linear, nonadiabatic pulsations, respectively. We derived the instability domains of β Cephei and SPB-types for different opacity tables OPLIB, OP, and OPAL. As a result, the new OPLIB opacities have the highest Rosseland mean opacity coefficient near the so-called Z-bump. Therefore, the OPLIB instability domains are wider than in the case of OP and OPAL data.

Wider pulsation instability regions for β Cephei and SPB stars calculated using new Los Alamos opacities

DOE PAGES

Walczak, Przemysław; Fontes, Christopher John; Colgan, James Patrick; ...

2015-08-13

Here, our goal is to test the newly developed OPLIB opacity tables from Los Alamos National Laboratory and check their influence on the pulsation properties of B-type stars. We calculated models using MESA and Dziembowski codes for stellar evolution and linear, nonadiabatic pulsations, respectively. We derived the instability domains of β Cephei and SPB-types for different opacity tables OPLIB, OP, and OPAL. As a result, the new OPLIB opacities have the highest Rosseland mean opacity coefficient near the so-called Z-bump. Therefore, the OPLIB instability domains are wider than in the case of OP and OPAL data.

Gradated assembly of multiple proteins into supramolecular nanomaterials

NASA Astrophysics Data System (ADS)

Hudalla, Gregory A.; Sun, Tao; Gasiorowski, Joshua Z.; Han, Huifang; Tian, Ye F.; Chong, Anita S.; Collier, Joel H.

2014-08-01

Biomaterials exhibiting precise ratios of different bioactive protein components are critical for applications ranging from vaccines to regenerative medicine, but their design is often hindered by limited choices and cross-reactivity of protein conjugation chemistries. Here, we describe a strategy for inducing multiple different expressed proteins of choice to assemble into nanofibres and gels with exceptional compositional control. The strategy employs ‘βTail’ tags, which allow for good protein expression in bacteriological cultures, yet can be induced to co-assemble into nanomaterials when mixed with additional β-sheet fibrillizing peptides. Multiple different βTail fusion proteins could be inserted into peptide nanofibres alone or in combination at predictable, smoothly gradated concentrations, providing a simple yet versatile route to install precise combinations of proteins into nanomaterials. The technology is illustrated by achieving precisely targeted hues using mixtures of fluorescent proteins, by creating nanofibres bearing enzymatic activity, and by adjusting antigenic dominance in vaccines.

Charged triblock copolymer self-assembly into charged micelles

NASA Astrophysics Data System (ADS)

Chen, Yingchao; Zhang, Ke; Zhu, Jiahua; Wooley, Karen; Pochan, Darrin; Department of Material Science; Engineering University of Delaware Team; Department of Chemistry Texas A&M University Collaboration

2011-03-01

Micelles were formed through the self-assembly of amphiphlic block copolymer poly(acrylic acid)-block-poly(methyl acrylate)-block-polystyrene (PAA-PMA-PS). ~Importantly, the polymer is complexed with diamine molecules in pure THF solution prior to water titration solvent processing-a critical aspect in the control of final micelle geometry. The addition of diamine triggers acid-base complexation ~between the carboxylic acid PAA side chains and amines. ~Remarkably uniform spheres were found to form close-packed patterns when forced into dried films and thin, solvated films when an excess of amine was used in the polymer assembly process. Surface properties and structural features of these hexagonal-packed spherical micelles with charged corona have been explored by various characterization methods including Transmission Electron Microscopy (TEM), cryogenic TEM, z-potential analysis and Dynamic Light Scattering. The forming mechanism for this pattern and morphology changes against external stimulate such as salt will be discussed.

Assembly of an FtsZ Mutant Deficient in GTPase Activity Has Implications for FtsZ Assembly and the Role of the Z Ring in Cell Division

PubMed Central

Mukherjee, Amit; Saez, Cristian; Lutkenhaus, Joe

2001-01-01

FtsZ, the ancestral homologue of eukaryotic tubulins, assembles into the Z ring, which is required for cytokinesis in prokaryotic cells. Both FtsZ and tubulin have a GTPase activity associated with polymerization. Interestingly, the ftsZ2 mutant is viable, although the FtsZ2 mutant protein has dramatically reduced GTPase activity due to a glycine-for-aspartic acid substitution within the synergy loop. In this study, we have examined the properties of FtsZ2 and found that the reduced GTPase activity is not enhanced by DEAE-dextran-induced assembly, indicating it has a defective catalytic site. In the absence of DEAE-dextran, FtsZ2 fails to assemble unless supplemented with wild-type FtsZ. FtsZ has to be at or above the critical concentration for copolymerization to occur, indicating that FtsZ is nucleating the copolymers. The copolymers formed are relatively stable and appear to be stabilized by a GTP-cap. These results indicate that FtsZ2 cannot nucleate assembly in vitro, although it must in vivo. Furthermore, the stability of FtsZ-FtsZ2 copolymers argues that FtsZ2 polymers would be stable, suggesting that stable FtsZ polymers are able to support cell division. PMID:11717278

Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

NASA Astrophysics Data System (ADS)

Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

2015-12-01

Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process.

Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

PubMed Central

Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

2015-01-01

Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process. PMID:26643504

Annual Report for Los Alamos National Laboratory Technical Area 54, Area G Disposal Facility - Fiscal Year 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birdsell, Kay Hanson; Stauffer, Philip H.; Atchley, Adam Lee

As a condition to the disposal authorization statement issued to Los Alamos National Laboratory (LANL or the Laboratory) on March 17, 2010, a comprehensive performance assessment and composite analysis (PA/CA) maintenance program must be implemented for the Technical Area 54, Area G disposal facility. Annual determinations of the adequacy of the PA/CA are to be conducted under the maintenance program to ensure that the conclusions reached by those analyses continue to be valid. This report summarizes the results of the fiscal year (FY) 2016 annual review for Area G.

Structural assembly in space

NASA Technical Reports Server (NTRS)

Stokes, J. W.; Pruett, E. C.

1980-01-01

A cost algorithm for predicting assembly costs for large space structures is given. Assembly scenarios are summarized which describe the erection, deployment, and fabrication tasks for five large space structures. The major activities that impact total costs for structure assembly from launch through deployment and assembly to scientific instrument installation and checkout are described. Individual cost elements such as assembly fixtures, handrails, or remote minipulators are also presented.

Space-charge-sustained microbunch structure in the Los Alamos Proton Storage Ring

NASA Astrophysics Data System (ADS)

Cousineau, S.; Danilov, V.; Holmes, J.; Macek, R.

2004-09-01

We present experimental data from the Los Alamos Proton Storage Ring (PSR) showing long-lived linac microbunch structure during beam storage with no rf bunching. Analysis of the experimental data and particle-in-cell simulations of the experiments indicate that space charge, coupled with energy spread effects, is responsible for the sustained microbunch structure. The simulated longitudinal phase space of the beam reveals a well-defined separatrix in the phase space between linac microbunches, with particles executing unbounded motion outside of the separatrix. We show that the longitudinal phase space of the beam was near steady state during the PSR experiments, such that the separatrix persisted for long periods of time. Our simulations indicate that the steady state is very sensitive to the experimental conditions. Finally, we solve the steady-state problem in an analytic, self-consistent fashion for a set of periodic longitudinal space-charge potentials.

Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution.

PubMed

Edwards-Gayle, Charlotte J C; Greco, Francesca; Hamley, Ian W; Rambo, Robert P; Reza, Mehedi; Ruokolainen, Janne; Skoulas, Dimitrios; Iatrou, Hermis

2018-01-08

We investigate the self-assembly of two telechelic star polymer-peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyrosine. The conjugates were prepared via N-carboxy anhydride-mediated ring-opening polymerization from PEO star polymer macroinitiators. Self-assembly occurs above a critical aggregation concentration determined via fluorescence probe assays. Peptide conformation was examined using circular dichroism spectroscopy. The structure of self-assembled aggregates was probed using small-angle X-ray scattering and cryogenic transmission electron microscopy. In contrast to previous studies on linear telechelic PEO-oligotyrosine conjugates that show self-assembly into β-sheet fibrils, the star architecture suppresses fibril formation and micelles are generally observed instead, a small population of fibrils only being observed upon pH adjustment. Hydrogelation is also suppressed by the polymer star architecture. These peptide-functionalized star polymer solutions are cytocompatible at sufficiently low concentration. These systems present tyrosine at high density and may be useful in the development of future enzyme or pH-responsive biomaterials.

Fibrillar α-Synuclein and Huntingtin Exon 1 Assemblies Are Toxic to the Cells

PubMed Central

Pieri, Laura; Madiona, Karine; Bousset, Luc; Melki, Ronald

2012-01-01

The aggregation of alpha-synuclein (α-syn) and huntingtin (htt) into fibrillar assemblies in nerve and glial cells is a molecular hallmark of Parkinson's and Huntington's diseases. Within the aggregation process, prefibrillar and fibrillar oligomeric species form. Prefibrillar assemblies rather than fibrils are nowadays considered cytotoxic. However, recent reports describing spreading of fibrillar assemblies from one cell to another, in cell cultures, animal models, and brains of grafted patients suggest a critical role for fibrillar assemblies in pathogenesis. Here we compare the cytotoxic effect of defined and comparable particle concentrations of on-assembly pathway oligomeric and fibrillar α-syn and Htt fragment corresponding to the first exon of the protein (HttEx1). We show that homogeneous populations of α-syn and HttEx1 fibrils, rather than their precursor on-assembly pathway oligomers, are highly toxic to cultured cells and induce apoptotic cell death. We document the reasons that make fibrils toxic. We show that α-syn and HttEx1 fibrils bind and permeabilize lipid vesicles. We also show that fibrils binding to the plasma membrane in cultured cells alter Ca2+ homeostasis. Overall, our data indicate that fibrillar α-syn and HttEx1, rather than their precursor oligomers, are highly cytotoxic, the toxicity being associated to their ability to bind and permeabilize the cell membranes. PMID:22735540

Membrane module assembly

DOEpatents

Kaschemekat, Jurgen

1994-01-01

A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

Yeast Mitoribosome Large Subunit Assembly Proceeds by Hierarchical Incorporation of Protein Clusters and Modules on the Inner Membrane.

PubMed

Zeng, Rui; Smith, Erin; Barrientos, Antoni

2018-03-06

Mitoribosomes are specialized for the synthesis of hydrophobic membrane proteins encoded by mtDNA, all essential for oxidative phosphorylation. Despite their linkage to human mitochondrial diseases and the recent cryoelectron microscopy reconstruction of yeast and mammalian mitoribosomes, how they are assembled remains obscure. Here, we dissected the yeast mitoribosome large subunit (mtLSU) assembly process by systematic genomic deletion of 44 mtLSU proteins (MRPs). Analysis of the strain collection unveiled 37 proteins essential for functional mtLSU assembly, three of which are critical for mtLSU 21S rRNA stability. Hierarchical cluster analysis of mtLSU subassemblies accumulated in mutant strains revealed co-operative assembly of protein sets forming structural clusters and preassembled modules. It also indicated crucial roles for mitochondrion-specific membrane-binding MRPs in anchoring newly transcribed 21S rRNA to the inner membrane, where assembly proceeds. Our results define the yeast mtLSU assembly landscape in vivo and provide a foundation for studies of mitoribosome assembly across evolution. Copyright © 2018 Elsevier Inc. All rights reserved.

A laboratory facility for research on wind-driven rain intrusion in building envelope assemblies

Treesearch

Samuel V. Glass

2010-01-01

Moisture management is critical for durable, energy-efficient buildings. To address the need for research on wind-driven rain intrusion in wall assemblies, the U.S. Forest Products Laboratory is developing a new facility. This paper describes the underlying principle of this facility and its capabilities.

Distinct roles for Arp2/3 regulators in actin assembly and endocytosis.

PubMed

Galletta, Brian J; Chuang, Dennis Y; Cooper, John A

2008-01-01

The Arp2/3 complex is essential for actin assembly and motility in many cell processes, and a large number of proteins have been found to bind and regulate it in vitro. A critical challenge is to understand the actions of these proteins in cells, especially in settings where multiple regulators are present. In a systematic study of the sequential multicomponent actin assembly processes that accompany endocytosis in yeast, we examined and compared the roles of WASp, two type-I myosins, and two other Arp2/3 activators, along with that of coronin, which is a proposed inhibitor of Arp2/3. Quantitative analysis of high-speed fluorescence imaging revealed individual functions for the regulators, manifested in part by novel phenotypes. We conclude that Arp2/3 regulators have distinct and overlapping roles in the processes of actin assembly that drive endocytosis in yeast. The formation of the endocytic actin patch, the creation of the endocytic vesicle, and the movement of the vesicle into the cytoplasm display distinct dependencies on different Arp2/3 regulators. Knowledge of these roles provides insight into the in vivo relevance of the dendritic nucleation model for actin assembly.

Assembly of collagen matrices as a phase transition revealed by structural and rheologic studies.

PubMed

Forgacs, Gabor; Newman, Stuart A; Hinner, Bernhard; Maier, Christian W; Sackmann, Erich

2003-02-01

We have studied the structural and viscoelastic properties of assembling networks of the extracellular matrix protein type-I collagen by means of phase contrast microscopy and rotating disk rheometry. The initial stage of the assembly is a nucleation process of collagen monomers associating to randomly distributed branched clusters with extensions of several microns. Eventually a sol-gel transition takes place, which is due to the interconnection of these clusters. We analyzed this transition in terms of percolation theory. The viscoelastic parameters (storage modulus G' and loss modulus G") were measured as a function of time for five different frequencies ranging from omega = 0.2 rad/s to 6.9 rad/s. We found that at the gel point both G' and G" obey a scaling law, with the critical exponent Delta = 0.7 and a critical loss angle being independent of frequency as predicted by percolation theory. Gelation of collagen thus represents a second order phase transition.

Induction of Micronuclei in Human Fibroblasts from the Los Alamos High Energy Neutron Beam

NASA Technical Reports Server (NTRS)

Cox, Bradley

2009-01-01

The space radiation field includes a broad spectrum of high energy neutrons. Interactions between these neutrons and a spacecraft, or other material, significantly contribute to the dose equivalent for astronauts. The 15 degree beam line in the Weapons Neutron Research beam at Los Alamos Nuclear Science Center generates a neutron spectrum relatively similar to that seen in space. Human foreskin fibroblast (AG1522) samples were irradiated behind 0 to 20 cm of water equivalent shielding. The cells were exposed to either a 0.05 or 0.2 Gy entrance dose. Following irradiation, micronuclei were counted to see how the water shield affects the beam and its damage to cell nuclei. Micronuclei induction was then compared with dose equivalent data provided from a tissue equivalent proportional counter.

Fragile X mental retardation protein stimulates ribonucleoprotein assembly of influenza A virus

NASA Astrophysics Data System (ADS)

Zhou, Zhuo; Cao, Mengmeng; Guo, Yang; Zhao, Lili; Wang, Jingfeng; Jia, Xue; Li, Jianguo; Wang, Conghui; Gabriel, Gülsah; Xue, Qinghua; Yi, Yonghong; Cui, Sheng; Jin, Qi; Wang, Jianwei; Deng, Tao

2014-02-01

The ribonucleoprotein (RNP) of the influenza A virus is responsible for the transcription and replication of viral RNA in the nucleus. These processes require interplay between host factors and RNP components. Here, we report that the Fragile X mental retardation protein (FMRP) targets influenza virus RNA synthesis machinery and facilitates virus replication both in cell culture and in mice. We demonstrate that FMRP transiently associates with viral RNP and stimulates viral RNP assembly through RNA-mediated interaction with the nucleoprotein. Furthermore, the KH2 domain of FMRP mediates its association with the nucleoprotein. A point mutation (I304N) in the KH2 domain, identified from a Fragile X syndrome patient, disrupts the FMRP-nucleoprotein association and abolishes the ability of FMRP to participate in viral RNP assembly. We conclude that FMRP is a critical host factor used by influenza viruses to facilitate viral RNP assembly. Our observation reveals a mechanism of influenza virus RNA synthesis and provides insights into FMRP functions.

Classification of self-assembling protein nanoparticle architectures for applications in vaccine design

NASA Astrophysics Data System (ADS)

Indelicato, G.; Burkhard, P.; Twarock, R.

2017-04-01

We introduce here a mathematical procedure for the structural classification of a specific class of self-assembling protein nanoparticles (SAPNs) that are used as a platform for repetitive antigen display systems. These SAPNs have distinctive geometries as a consequence of the fact that their peptide building blocks are formed from two linked coiled coils that are designed to assemble into trimeric and pentameric clusters. This allows a mathematical description of particle architectures in terms of bipartite (3,5)-regular graphs. Exploiting the relation with fullerene graphs, we provide a complete atlas of SAPN morphologies. The classification enables a detailed understanding of the spectrum of possible particle geometries that can arise in the self-assembly process. Moreover, it provides a toolkit for a systematic exploitation of SAPNs in bioengineering in the context of vaccine design, predicting the density of B-cell epitopes on the SAPN surface, which is critical for a strong humoral immune response.

LightAssembler: fast and memory-efficient assembly algorithm for high-throughput sequencing reads.

PubMed

El-Metwally, Sara; Zakaria, Magdi; Hamza, Taher

2016-11-01

The deluge of current sequenced data has exceeded Moore's Law, more than doubling every 2 years since the next-generation sequencing (NGS) technologies were invented. Accordingly, we will able to generate more and more data with high speed at fixed cost, but lack the computational resources to store, process and analyze it. With error prone high throughput NGS reads and genomic repeats, the assembly graph contains massive amount of redundant nodes and branching edges. Most assembly pipelines require this large graph to reside in memory to start their workflows, which is intractable for mammalian genomes. Resource-efficient genome assemblers combine both the power of advanced computing techniques and innovative data structures to encode the assembly graph efficiently in a computer memory. LightAssembler is a lightweight assembly algorithm designed to be executed on a desktop machine. It uses a pair of cache oblivious Bloom filters, one holding a uniform sample of [Formula: see text]-spaced sequenced [Formula: see text]-mers and the other holding [Formula: see text]-mers classified as likely correct, using a simple statistical test. LightAssembler contains a light implementation of the graph traversal and simplification modules that achieves comparable assembly accuracy and contiguity to other competing tools. Our method reduces the memory usage by [Formula: see text] compared to the resource-efficient assemblers using benchmark datasets from GAGE and Assemblathon projects. While LightAssembler can be considered as a gap-based sequence assembler, different gap sizes result in an almost constant assembly size and genome coverage. https://github.com/SaraEl-Metwally/LightAssembler CONTACT: sarah_almetwally4@mans.edu.egSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 5 2012-10-01 2012-10-01 false Seats, seat belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to Transportation... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses...

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Seats, seat belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to Transportation... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses...

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Seats, seat belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to Transportation... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses...

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Seats, seat belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to Transportation... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses...

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Seats, seat belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to Transportation... § 393.93 Seats, seat belt assemblies, and seat belt assembly anchorages. (a) Buses—(1) Buses...

Biomineralization of a Self-assembled, Soft-Matrix Precursor: Enamel

NASA Astrophysics Data System (ADS)

Snead, Malcolm L.

2015-04-01

Enamel is the bioceramic covering of teeth, a composite tissue composed of hierarchical organized hydroxyapatite crystallites fabricated by cells under physiologic pH and temperature. Enamel material properties resist wear and fracture to serve a lifetime of chewing. Understanding the cellular and molecular mechanisms for enamel formation may allow a biology-inspired approach to material fabrication based on self-assembling proteins that control form and function. A genetic understanding of human diseases exposes insight from nature's errors by exposing critical fabrication events that can be validated experimentally and duplicated in mice using genetic engineering to phenocopy the human disease so that it can be explored in detail. This approach led to an assessment of amelogenin protein self-assembly that, when altered, disrupts fabrication of the soft enamel protein matrix. A misassembled protein matrix precursor results in loss of cell-to-matrix contacts essential to fabrication and mineralization.

Assembly-directed antivirals differentially bind quasiequivalent pockets to modify hepatitis B virus capsid tertiary and quaternary structure.

PubMed

Katen, Sarah P; Tan, Zhenning; Chirapu, Srinivas Reddy; Finn, M G; Zlotnick, Adam

2013-08-06

Hepatitis B virus (HBV) is a major cause of liver disease. Assembly of the HBV capsid is a critical step in virus production and an attractive target for new antiviral therapies. We determined the structure of HBV capsid in complex with AT-130, a member of the phenylpropenamide family of assembly effectors. AT-130 causes tertiary and quaternary structural changes but does not disrupt capsid structure. AT-130 binds a hydrophobic pocket that also accommodates the previously characterized heteroaryldihydropyrimidine compounds but favors a unique quasiequivalent location on the capsid surface. Thus, this pocket is a promiscuous drug-binding site and a likely target for different assembly effectors with a broad range of mechanisms of activity. That AT-130 successfully decreases virus production by increasing capsid assembly rate without disrupting capsid structure delineates a paradigm in antiviral design, that disrupting reaction timing is a viable strategy for assembly effectors of HBV and other viruses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Membrane module assembly

DOEpatents

Kaschemekat, J.

1994-03-15

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

Development of the Los Alamos National Laboratory Cryogenic Pressure Loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebey, Peter S.; Dole, James M.; Hoffer, James K.

2003-05-15

Targets for inertial fusion research and ignition at OMEGA, the National Ignition Facility, LMJ, and future facilities rely on beta-radiation-driven layering of spherical cryogenic DT ice layers contained within plastic or metal shells. Plastic shells will be permeation filled at room temperature then cooled to cryogenic temperatures before removal of the overpressure. The cryogenic pressure loader (CPL) was recently developed at Los Alamos National Laboratory as a testbed for studying the filling and layering of plastic target shells with DT. A technical description of the CPL is provided. The CPL consists of a cryostat, which contains a high-pressure permeation cell,more » and has optical access for investigating beta layering. The cryostat is housed within a tritium glovebox that contains manifolds for supplying high-pressure DT. The CPL shares some design elements with the cryogenic target handling system at the OMEGA facility to allow testing of tritium issues related to that system. The CPL has the capability to fill plastic targets by permeation to pressures up to 100 MPa and to cool them to 15 K. The CPL will accommodate a range of targets and may be modified for future experiments.« less

Thermally Simulated 32kW Direct-Drive Gas-Cooled Reactor: Design, Assembly, and Test

NASA Astrophysics Data System (ADS)

Godfroy, Thomas J.; Kapernick, Richard J.; Bragg-Sitton, Shannon M.

2004-02-01

One of the power systems under consideration for nuclear electric propulsion is a direct-drive gas-cooled reactor coupled to a Brayton cycle. In this system, power is transferred from the reactor to the Brayton system via a circulated closed loop gas. To allow early utilization, system designs must be relatively simple, easy to fabricate, and easy to test using non-nuclear heaters to closely mimic heat from fission. This combination of attributes will allow pre-prototypic systems to be designed, fabricated, and tested quickly and affordably. The ability to build and test units is key to the success of a nuclear program, especially if an early flight is desired. The ability to perform very realistic non-nuclear testing increases the success probability of the system. In addition, the technologies required by a concept will substantially impact the cost, time, and resources required to develop a successful space reactor power system. This paper describes design features, assembly, and test matrix for the testing of a thermally simulated 32kW direct-drive gas-cooled reactor in the Early Flight Fission - Test Facility (EFF-TF) at Marshall Space Flight Center. The reactor design and test matrix are provided by Los Alamos National Laboratories.

Material selection and assembly method of battery pack for compact electric vehicle

NASA Astrophysics Data System (ADS)

Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.

2018-01-01

Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

2010 Critical Success Factors for the North Carolina Community College System. Twenty First Annual Report

ERIC Educational Resources Information Center

North Carolina Community College System (NJ1), 2010

2010-01-01

First mandated by the North Carolina General Assembly in 1989 (S.L. 1989; C. 752; S. 80), the Critical Success Factors report has evolved into the major accountability document for the North Carolina Community College System. This twenty first annual report on the critical success factors is the result of a process undertaken to streamline and…

Immature HIV-1 lattice assembly dynamics are regulated by scaffolding from nucleic acid and the plasma membrane

PubMed Central

Pak, Alexander J.; Grime, John M. A.; Sengupta, Prabuddha; Chen, Antony K.; Durumeric, Aleksander E. P.; Srivastava, Anand; Yeager, Mark; Briggs, John A. G.; Lippincott-Schwartz, Jennifer; Voth, Gregory A.

2017-01-01

The packaging and budding of Gag polyprotein and viral RNA is a critical step in the HIV-1 life cycle. High-resolution structures of the Gag polyprotein have revealed that the capsid (CA) and spacer peptide 1 (SP1) domains contain important interfaces for Gag self-assembly. However, the molecular details of the multimerization process, especially in the presence of RNA and the cell membrane, have remained unclear. In this work, we investigate the mechanisms that work in concert between the polyproteins, RNA, and membrane to promote immature lattice growth. We develop a coarse-grained (CG) computational model that is derived from subnanometer resolution structural data. Our simulations recapitulate contiguous and hexameric lattice assembly driven only by weak anisotropic attractions at the helical CA–SP1 junction. Importantly, analysis from CG and single-particle tracking photoactivated localization (spt-PALM) trajectories indicates that viral RNA and the membrane are critical constituents that actively promote Gag multimerization through scaffolding, while overexpression of short competitor RNA can suppress assembly. We also find that the CA amino-terminal domain imparts intrinsic curvature to the Gag lattice. As a consequence, immature lattice growth appears to be coupled to the dynamics of spontaneous membrane deformation. Our findings elucidate a simple network of interactions that regulate the early stages of HIV-1 assembly and budding. PMID:29114055

Crystalline modification of a rare earth nucleating agent for isotactic polypropylene based on its self-assembly.