Laboratory Advanced Research Articles

Phase Contrast X‐Ray Imaging of the Collapse of an Engineered Void in Single‐Crystal HMX

AbstractImaging the collapse of a single void that creates a hot spot initiation site in an otherwise defect‐free explosive is challenging given the spatial and temporal scales involved in explosive systems. This work presents our attempt to examine a single hot spot mode (void collapse) in single‐crystal octahydro‐l,3,5,7‐tetranitro‐l,3,5,7‐tetrazocine (HMX) embedded in Sylgard. The hot spot heating mechanisms involved with pore collapse include adiabatic heating, jetting, and viscoplastic dissipation. Quantifying the dynamics of a pore collapse is a crucial step to understanding which mechanisms dominate during ignition events. Our experiments were conducted with a single‐stage, light‐gas gun at Argonne National Laboratory's Advanced Photon Source, applying the phase contrast imaging technique while collecting high‐speed video. The details of HMX single crystal production, defect (pore) engineering, and sample construction, along with experimental results are presented here. These results demonstrate that detailed collapse dynamics can be obtained from homogeneous, single‐crystal explosives with this approach. Qualitative comparisons are made with simulation data which show good agreement in the transition between a quasi‐symmetric pore collapse and an asymmetric collapse with jetting across the pore as measured with normalized pore area and pore circularity.

Chronic Musculoskeletal Pain Moderates the Association between Sleep Quality and Dorsostriatal-Sensorimotor Resting State Functional Connectivity in Community-Dwelling Older Adults

Aging is associated with poor sleep quality, and greater chronic pain prevalence with age-related changes in brain function as potential underlying mechanisms. The following cross-sectional study aimed to determine whether self-reported chronic musculoskeletal pain in community-dwelling older adults moderates the association between sleep quality and resting state functional brain connectivity (rsFC). Community-dwelling older individuals (mean age=73.29 years) part of the NEPAL study who completed the Pittsburg Sleep Quality Index (PSQI) and an rsFC scan were included (n=48) in the present investigation. To that end, we tested the effect of chronic pain-by-PSQI interaction on rsFC among atlas-based brain regions-of-interest, controlling for age and sex. A significant network connecting the bilateral putamen and left caudate with bilateral precentral gyrus, postcentral gyrus and juxtapositional lobule cortex, survived global multiple comparisons (FDR; q<0.05) and threshold-free network-based-statistics. Greater PSQI scores were significantly associated with greater dorsostriatal-sensorimotor rsFC in the no-pain group, suggesting that a state of somatomotor hyperarousal may be associated with poorer sleep quality in this group. However, in the pain group greater PSQI scores were associated with less dorsostriatal-sensorimotor rsFC, possibly due to a shift of striatal functions toward regulation sensorimotor aspects of the pain experience, and/or aberrant cortico-striatal loops in the presence of chronic pain. This preliminary investigation advances knowledge about the neurobiology underlying the associations between chronic pain and sleep in community-dwelling older adults that may contribute to the development of effectitractve therapies to decrease disability in geriatric populations. This work was supported by the National Institutes of Aging (NIAK01AG048259, R01AG059809, R01AG067757, and T32AG049673). A portion of this work was performed in the McKnight Brain Institute at the National High Magnetic Field Laboratory's Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility, which is supported by National Science Foundation Cooperative Agreement No. DMR-1644779 and DMR-1157490, and the State of Florida and the University of Florida Claude D. Pepper Older Americans Independence Center.

Ultrafast x-ray imaging of pulsed plasmas in water

Pulsed plasmas in liquids exhibit complex interaction between three phases of matter (liquids, gas, plasmas) and are currently used in a wide range of applications across several fields, however significant knowledge gaps in our understanding of plasma initiation in liquids hinder additional application and control; this area of research currently lacks a comprehensive predictive model. To aid progress in this area experimentally, here we present the first-known ultrafast (50 ps) X-ray images of pulsed plasma initiation processes in water (+25 kV, 10 ns, 5 mJ), courtesy of the X-ray imaging techniques available at Argonne National Laboratory's Advanced Photon Source (APS), with supporting nanosecond optical imaging and a computational X-ray diffraction model. These results clearly resolve narrow (~10 micron) low-density plasma channels during initiation timescales typically obscured by optical emission (<100 ns), a well-known and difficult problem to plasma experiments without access to state-of-the-art X-ray sources such as the APS synchrotron. Images presented in this work speak to several of the prevailing plasma initiation hypotheses, supporting electrostriction and bubble deformation as dominant initiation phenomena. We also demonstrate the plasma setup used in this work as a cheap ($<$US\$100k), compact, and repeatable benchmark imaging target (29.1 km/s, 1 TW/cm$^2$) useful for the development of next-generation ultrafast imaging of high-energy-density physics (HEDP), as well as easier integration of HEDP research into synchrotron-enabled facilities.

Time resolved small angle X-ray scattering experiments performed on detonating explosives at the advanced photon source: Calculation of the time and distance between the detonation front and the x-ray beam

Time resolved Small Angle X-ray Scattering (SAXS) experiments on detonating explosives have been conducted at Argonne National Laboratory's Advanced Photon Source Dynamic Compression Sector. The purpose of the experiments is to measure the SAXS patterns at tens of ns to a few μs behind the detonation front. Corresponding positions behind the detonation front are of order 0.1–10 mm. From the scattering patterns, properties of the explosive products relative to the time behind the detonation front can be inferred. This report describes how the time and distance from the x-ray probe location to the detonation front is calculated, as well as the uncertainties and sources of uncertainty associated with the calculated times and distances.

Process R&D and Scale-up of Advanced Battery Materials at Argonne's Materials Engineering Research Facility

Argonne's Materials Engineering Research Facility (MERF) supports the laboratory's Advanced Battery Materials Synthesis and Manufacturing R&D Program. The MERF is enabling the development of manufacturing processes for producing advanced battery materials in sufficient quantity for industrial testing. The engineering research conducted in this program is known as process scale-up. Scale-up R&D involves taking a laboratory-developed material and developing a safe, reliable and economical commercial-scale process. This represents one of the most significant hurdles in transitioning new battery materials and technologies to the market. By bridging the gap between small-scale laboratory research and high-volume battery manufacturing, research at the MERF will lead to substantial progress in the development, validation and ultimate commercialization of advanced battery materials chemistries. In addition, advanced manufacturing processes are investigated to determine performance and cost benefits to material production. Advanced materials produced are then made available to the battery research community to further their work using high quality, standardized baseline materials. An overview of the program will be given as well as a summary of current scale-up projects.

Institutional persistence and the material transformation of the US national labs: The curious story of the advent of the Advanced Photon Source

The 1990s saw a radical shift in the US investment in large-scale projects along with a shift in the rationale for US support of such projects and the national laboratories which host them. Previously, the largest projects were for the esoteric field of high energy and justifications drew on the Cold War priorities of national security and the cultural benefits of a free society. Starting with Argonne National Laboratory's Advanced Photon Source, a materials science accelerator, all this changed. From this time forward those promoting large-scale projects instead pointed to more practical considerations in line with the post-Cold-War moral economy valuing entrepreneurship and measurable utility. It might seem that change resulted from a direct competition between high energy physicists and materials scientists that was mediated by high-level policy makers in favor of the latter. This case study reveals a much more telling and nuanced story in which science policy was shaped at every turn by the need of the US national laboratories to adapt to a changing social, political, economic, technological and scientific context amidst the underlying desire for institutional persistence. Copyright The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com, Oxford University Press.

Mechanistic Details of Glutathione Biosynthesis Revealed by Crystal Structures of Saccharomyces cerevisiae Glutamate Cysteine Ligase

Glutathione is a thiol-disulfide exchange peptide critical for buffering oxidative or chemical stress, and an essential cofactor in several biosynthesis and detoxification pathways. The rate-limiting step in its de novo biosynthesis is catalyzed by glutamate cysteine ligase, a broadly expressed enzyme for which limited structural information is available in higher eukaryotic species. Structural data are critical to the understanding of clinical glutathione deficiency, as well as rational design of enzyme modulators that could impact human disease progression. Here, we have determined the structures of Saccharomyces cerevisiae glutamate cysteine ligase (ScGCL) in the presence of glutamate and MgCl(2) (2.1 A; R = 18.2%, R(free) = 21.9%), and in complex with glutamate, MgCl(2), and ADP (2.7 A; R = 19.0%, R(free) = 24.2%). Inspection of these structures reveals an unusual binding pocket for the alpha-carboxylate of the glutamate substrate and an ATP-independent Mg(2+) coordination site, clarifying the Mg(2+) dependence of the enzymatic reaction. The ScGCL structures were further used to generate a credible homology model of the catalytic subunit of human glutamate cysteine ligase (hGCLC). Examination of the hGCLC model suggests that post-translational modifications of cysteine residues may be involved in the regulation of enzymatic activity, and elucidates the molecular basis of glutathione deficiency associated with patient hGCLC mutations.

Fuel economy and emissions evaluation of BMW Hydrogen 7 Mono-Fuel demonstration vehicles

This article summarizes the testing of two BMW Hydrogen 7 Mono-Fuel demonstration vehicles at Argonne National Laboratory's Advanced Powertrain Research Facility (APRF). The BMW Hydrogen 7 Mono-Fuel demonstration vehicles are derived from the BMW Hydrogen 7 bi-fuel vehicles and based on a BMW 760iL. The mono-fuel as well as the bi-fuel vehicle(s) is equipped with cryogenic hydrogen on-board storage and a gaseous hydrogen port fuel injection system. The BMW Hydrogen 7 Mono-Fuel demonstration vehicles were tested for fuel economy as well as emissions on the Federal Test Procedure FTP-75 cold-start test as well as the highway test. The results show that these vehicles achieve emissions levels that are only a fraction of the Super Ultra Low Emissions Vehicle (SULEV) standard for nitric oxide (NO x ) and carbon monoxide (CO) emissions. For non-methane hydrocarbon (NMHC) emissions the cycle-averaged emissions are actually 0 g/mile, which require the car to actively reduce emissions compared to the ambient concentration. The fuel economy numbers on the FTP-75 test were 3.7 kg of hydrogen per 100 km, which, on an energy basis, is equivalent to a gasoline fuel consumption of 17 miles per gallon (mpg). Fuel economy numbers for the highway cycle were determined to be 2.1 kg of hydrogen per 100 km or 30 miles per gallon of gasoline equivalent (GGE). In addition to cycle-averaged emissions and fuel economy numbers, time-resolved (modal) emissions as well as air/fuel ratio data is analyzed to further investigate the root causes of the remaining emissions traces. The BMW Hydrogen 7 vehicles employ a switching strategy with lean engine operation at low engine loads and stoichiometric operation at high engine loads that avoids the NO x emissions critical operating regime with relative air/fuel ratios between 1 < λ < 2. The switching between these operating modes was found to be a major source of the remaining NO x emissions. The emissions results collected during this period lead to the conclusion that the BMW Hydrogen 7 Mono-Fuel demonstration vehicles are likely the cleanest combustion engine vehicles ever tested at Argonne's APRF.

Duel-Band Infared Imagery of an Atlas 5 Launch Vehicle in Flight

Imagery acquired with a quantum-well infrared photodetector dual-band infrared focal plane array of the inaugural launch of the Atlas 5 launch vehicle is presented. The focal plane array was developed under the U.S. Army Research Laboratory's Advanced Sensors Federated Laboratory program and used a read-out integrated circuit produced under the Air Force Research Laboratory's Advanced Multi-Quantum Well Technology program. The detectors are able to sense light in both the 3-5- and 8-12-μm atmospheric transmission windows such that the resulting single-band images are pixel registered and simultaneous. The focal plane array was installed in a camera system that used a closed-cycle cooler to operate at 60 K. The camera was placed at the prime focus of an all-reflective telescope on a computer-controlled tracking mount at the Innovative Sensor Technology Evaluation Facility at the Kennedy Space Center. The launch was observed from a distance of 15 km from the pad. The dual-band camera system was calibrated using standard blackbody sources. The launch vehicle was observed from about 30 s after launch until approximately 4 min after launch. This corresponded to ranges between 15 km and more than 300 km and altitudes from just over 1 km to more than 100 km

Design and implementation of a vacuum-compatible laser-based subnanometer-resolution absolute distance measurement system

We describe the design and implementation of a vacuum compatible laser-based absolute distance measurement gauge with sub-nm resolution. The present system is compatible with operation in the 10{sup -8} Torr range and with some minor modifications could be used in the 10{sup -9} Torr range. The system is based on glancing incidence reflection and dual segmented diode detection. The system has been implemented as a focus sensor for extreme ultraviolet interferometry and microlithography experiments at Lawrence Berkeley National Laboratory's Advanced Light Source synchrotron radiation facility and 1{sigma} operational measurement noise floor of 0.26 nm has been demonstrated.

Air Force Research Laboratory Advanced Compact Range RCS uncertainty analysis for a general target

A calibration uncertainty analysis was conducted for the Air Force Research Laboratory's (AFRL's) Advanced Compact Range (ACR) in 2000. This analysis was a key component of the Radar Cross Section (RCS) ISO-25 (ANSI-Z-540) Range Certification Demonstration Project. The scope of the RCS uncertainty analysis for the demonstration project-was limited to calibration targets. Since that time, we have initiated a detailed RCS uncertainty analysis for a more-typical measured in the ACR. A more is one that is much larger with respect to a wavelength than the calibration targets, and that is characterized by a wide dynamic range of RCS scattering levels. We chose a 10-foot ogive as the target, due to the fact it was a large target, exhibited a wide dynamic range of scattering, and the scattering levels could be predicted using readily available CEM codes. We present the methodology for the uncertainty analysis and detailed analyses of selected component uncertainties. The aspects of the uncertainty analysis that are unique to the typical target (i.e., a non-calibration target) are emphasized.

Tolerancing of diffraction-limited Kirkpatrick–Baez synchrotron beamline optics for extreme-ultraviolet metrology

The recent interest in extreme-ultraviolet (EUV) lithography has led to the development of an array of at-wavelength metrologies implemented on synchrotron beamlines. These beamlines commonly use Kirkpatrick-Baez (K-B) systems consisting of two perpendicular, elliptically bent mirrors in series. To achieve high-efficiency focusing into a small spot, unprecedented fabrication and assembly tolerance is required of these systems. Here we present a detailed error-budget analysis and develop a set of specifications for diffraction-limited performance for the K-B optic operating on the EUV interferometry beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The specifications are based on code v modeling tools developed explicitly for these optical systems. Although developed for one particular system, the alignment sensitivities presented here are relevant to K-B system designs in general.

Sequestration of the Active Site by Interdomain Shifting: CRYSTALLOGRAPHIC AND SPECTROSCOPIC EVIDENCE FOR DISTINCT CONFORMATIONS OF l-3-HYDROXYACYL-CoA DEHYDROGENASE

Sequestration of the Active Site by Interdomain Shifting: CRYSTALLOGRAPHIC AND SPECTROSCOPIC EVIDENCE FOR DISTINCT CONFORMATIONS OF l-3-HYDROXYACYL-CoA DEHYDROGENASE

Electronic structure ofCu1−xNixRh2S4andCuRh2Se4: Band-structure calculations, x-ray photoemission, and fluorescence measurements

The electronic structure of spinel-type Cu_(1-x)Ni_xRh_2S_4 (x = 0.0, 0.1, 0.3, 0.5, 1.0) and CuRh_2Se_4 compounds has been studied by means of X-ray photoelectron and fluorescent spectroscopy. Cu L_3, Ni L_3, S L_(2,3) and Se M_(2,3) X-ray emission spectra (XES) were measured near thresholds at Beamline 8.0 of the Lawrence Berkeley Laboratory's Advanced Light Source. XES measurements of the constituent atoms of these compounds, reduced to the same binding energy scale, are found to be in excellent agreement with XPS valence bands. The calculated XES spectra which include dipole matrix elements show that the partial density of states reproduce experimental spectra quite well. States near the Fermi level (E_F) have strong Rh d and S(Se) p character in all compounds. In NiRh_2S_4 the Ni 3d states contribute strongly at E_F, whereas in both Cu compounds the Cu 3d bands are only ~1 eV wide and centered ~2.5 eV below E_F, leaving very little 3d character at E_F. The density of states at the Fermi level is less in NiRh_2S_4 than in CuRh_2S_4. This difference may contribute to the observed decrease, as a function of Ni concentration, in the superconducting transition temperature in Cu_(1-x)Ni_xRh_2S_4. The density of states of the ordered alloy Cu_(1/2)Ni_(1/2)Rh_2S_4 shows behavior that is more ``split-band''-like than ``rigid band''-like.

Active vibration control of large optical space structures

The paper describes techniques for designing and implementing active damping systems for large optical support structures. Each step in the design process is illustrated with results from the Advanced Composites with Embedded Sensors and Actuators (ACESA) vibration control system. The system is installed on a space based laser structural simulator at the Air Force Research Laboratory's Advanced Space Structure Research Experiments facility. The ACESA system consists of three large tubular active members; embedded bad zirconate-titanate (PZTs) wafers in each strut, which allows control of deformation axially and in two bending planes; 400 V drive electronics for each active member; and a nine-channel, digitally programmable, analogue control electronics unit. Design begins with the determination of the critical modes through a gain factor analysis. Actuators are located through modal strain energy analysis. Using piezostructural analysis methods, sensing and actuation functions are included in the open- and closed-loop dynamic simulations. The simulation includes local strain feedthrough effects through a static correction. Damping is applied to all modes in the frequency range up to 100 Hz, with fundamental modes achieving 20% damping, two orders of magnitude greater than the intrinsic damping level. The actuator PZTs used for active damping were also experimentally shunted with resistive elements in an attempt to introduce passive damping, although the effect was barely measurable. This demonstrates that active damping gives three orders of magnitude better performance than a passive resistive shunt in a controlled comparison.

Taking MAD to the extreme: ultrafast protein structure determination.

Multiwavelength anomalous diffraction data were measured in 23 min from a 16 kDa selenomethionyl substituted protein, producing experimental phases to 2.25 A resolution. The data were collected on a mosaic 3 x 3 charge-coupled device using undulator radiation from the Structural Biology Center 19ID beamline at the Argonne National Laboratory's Advanced Photon Source. The phases were independently obtained semiautomatically by two crystallographic program suites, CCP4 and CNS. The quality and speed of this data acquisition exemplify the opportunities at third-generation synchrotron sources for high-throughput protein crystal structure determination.

Experimental Study of Electronically Based Instrument Approach Plates

Issues associated with the electronic presentation of instrument approach plates (IAPs) were investigated in a part-task simulation study using the Massachusetts Institute of Technology Aeronautical Systems Laboratory's Advanced Cockpit Simulator. Several electronic IAP chart formats were developed and evaluated. A decluttering system that allowed the pilots to selectively suppress various information groups in some of the prototype formats was also investigated. Results of the experimental study indicated that there was no degradation, and possibly a limited gain in information-retrieval performance when IAP information was presented in electronic format and compared to traditional paper IAPs. Each pilot preferred the selectable decluttering feature. The preferred chart was a color, north-up (nonmoving map) format with the decluttering capability. During the simulation, low levels of terrain situational awareness were observed when pilots were given erroneous air traffic control vectors toward hazardous terrain.

AN EXPERT SYSTEM FOR TUNING PARTICLE BEAM ACCELERATORS

An expert system that acts as an intelligent assistant to operators tuning a particle beam accelerator was developed. The system incorporates three approaches to tuning: (1) Duplicating within a software program the reasoning and the procedures used by an operator to tune an accelerator. This approach has been used to steer particle beams through the transport section of Lawrence Livermore National Laboratory's Advanced Test Accelerator and through the injector section of the Experimental Test Accelerator. (2) Using a model to simulate the position of a beam in an accelerator. The simulation is based on data taken directly from the accelerator while it is running. This approach will ultimately be used by operators of the Experimental Test Accelerator to first compare actual and simulated beam performance in real time, then to determine which set of parameters is optimum in terms of centering the beam, and finally to feed those parameters to the accelerator. Operators can also use the model to determine if a component has failed. (3) Using a mouse to manually select and control the magnets that steer the beam. Operators on the Experimental Test Accelerator can also use the mouse to call up windows that display the horizontal and vertical positions of the beam as well as its current.

PRAISDPD: An aging pipe reliability analysis PC code

A double guillotine break of primary piping when a reactor is at full power has long been considered a bounding accident. But just what is its probability of occurrence? This paper presents a review of attempts to assess the probability of this never occurring event from WASH-1400 through the Thomas model to efforts using probabilistic fracture mechanics as exemplified in the PRAISE code which resulted in a revision of the Code of Federal Regulations to recognize the tendency of pipe to leak-before-break. The interactive PC code PRAISDPD implements the PRAISE algorithms and was used to perform safety optimizing parametric studies of Oak Ridge National Laboratory's Advanced Neutron Source (ANS) reactor. From this, the sensitivity of the pipe break probability to the piping parameters were determined and suggestions were made to minimize the break probability. Qualitative conclusions are: 1. • Pipe lengths should be minimized. 2. • Large diameter pipe is more reliable than smaller pipe because of the greater wall thickness through which a crack must grow and the larger circumference around which a crack must grow before becoming unstable with subsequent breakage. 3. • The probability of leakage and breakage is significantly reduced by periodic non-destructive examination (NDE—specifically ultrasound testing). 4. • Aging increases the probability of leak/break.

PRA using event tables and the Brookhaven event tree analyzer (BETA)

Event trees are key elements in applying PRA in pre-conceptual design for safety enhancement of Oak Ridge National Laboratory's Advanced Neutron Source (ANS) research reactor which will be the world's best source of low-energy neutrons for material studies, physics research, transplutonium production and radiation effects. Event trees exhaustively explore the combinations of system failures that may follow from accident initiator through dendritic diagrams connecting initiator with plant damage state and by calculating the frequency of each accident sequence. They are the central element of PRA, but require supplementary text to relate the sequences to plant systems, explain the logic and state assumptions. These tasks are accomplished by the integration of a popular word processor and the event tree analysis code BETA. Using the worl processor, the analyst writes text that describes each sequence to a depth deemed necessary and prepares an Event Table which indicates by symbols the operability of each system in the accident sequence and the judged fuel damage state. The matrix of symbols so formed is copied to another file, edited to remove spaces, additional information is added and the file is saved in ASCII format to provide input to BETA. BETA, which may be used for further editing, displays or plots on HP laser or Epson printer, the event tree specified by the Event Table logic and computes, displays and/or prints the end or intermediate state probabilities according to damage criteria. It also provides for changing nodal probabilities within the event tree according to the preceding sequences (‘binary conditionals’). The size of event trees is essentially unlimited by its ability to branch and link with other event trees. Work sessions may be saved to floppy or hard disk for recall. This paper describes how to use BETA, and how it works.