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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

The Test and Evaluation of a Non-Chromate Finishing Agent

This research is focused on the design, development and implementation of an industry, military and commercial standard testing cell for surface coatings, which focuses on advanced non-chromate materials technology and their commercialization. Currently, within both private and commercial sectors, chromates are used in the corrosion prevention. processes. However, there is a great demand for chromate-free systems that are able to provide equal protection. At the end of this effort, it is intended that a patented alternative to chromate conversion coatings would be tested and processed for commercialization. Thus far, research studies have been concerned primarily with current corrosion knowledge and testing methods. Corrosion can be classified into five categories: The first type is uniform corrosion which is dominated by a uniform thinning due to an even and regular loss of metal. The second type is called localized corrosion in which most of the loss occurs in discrete areas. The third type, metallurgically influenced corrosion is a form of attack where metallurgy plays a significant role. The fourth type, titled mechanically assisted degradation is a form of attack where velocity, abrasion, and hydrodynamics control the corrosion process. The last type of corrosion is defined as environmentally induced cracking which occurs when cracks are produced under specific, premeditated stress. Oddly enough, with these varying classifications, there are not as many standardized corrosion testing sites. Two of the most common testing methods for corrosion are salt spray testing and filiform. Although neither has proven to be absolute, in terms of the resulting observations, our research aims to help provide data that may be used to support the standardization for corrosion testing. We would acquire and use a Singleton Cyclic Corrosion Testing Chamber. Singleton test chambers perform a wide range of commonly used catalytic corrosion tests. They are used throughout the industry, some of which are - automotive, aerospace, electronic and many more. In addition to this, Singleton test chambers are fully expandable to accommodate cyclic corrosion testing needs. Singleton chambers are also designed for complete compliance and conformity with ASTM (American Society for Testing and Materials), military and commercial standards.

Gulley, H.↗
DOE OSTI2011

Chromaticity correction for a muon collider optics

Muon Collider (MC) is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 10{sup 34} cm{sup 2}s{sup -1} range the collider lattice designmust satisfy a number of stringent requirements. In particular the expected large momentum spread of the muon beam and the very small {beta}* call for a careful correction of the chromatic effects. Here we present a particular solution for the interaction region (IR) optics whose distinctive feature is a three-sextupole local chromatic correction scheme. The scheme may be applied to other future machines where chromatic effects are expected to be large. The expected large muon energy spread requires the optics to be stable over a wide range of momenta whereas the required luminosity calls for {beta}* in the mm range. To avoid luminosity degradation due to hour-glass effect, the bunch length must be comparatively small. To keep the needed RF voltage within feasible limits the momentum compaction factor must be small over the wide range of momenta. A low {beta}* means high sensitivity to alignment and field errors of the Interaction Region (IR) quadrupoles and large chromatic effects which limit the momentum range of optics stability and require strong correction sextupoles, which eventually limit the Dynamic Aperture (DA). Finally, the ring circumference should be as small as possible, luminosity being inversely proportional to the collider length. A promising solution for a 1.5 TeV center of mass energy MC with {beta}* = 1 m in both planes has been proposed. This {beta}* value has been chosen as a compromise between luminosity and feasibility based on the magnet design and energy deposition considerations. The proposed solution for the IR optics together with a new flexible momentum compaction arc cell design allows to satisfy all requirements and is relatively insensitive to the beam-beam effect.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Chromatic and Dispersive Effects in Nonlinear Integrable Optics

Proton accumulator rings and other circular hadron accelerators are susceptible to intensity-driven parametric instabilities because the zero-current charged particle dynamics are characterized by a single tune. Landau damping can suppress these instabilities, which requires energy spread in the beam or introducing nonlinear magnets such as octupoles. However, this approach reduces dynamic aperture. Nonlinear integrable optics can suppress parametric instabilities independent of energy spread in the distribution, while preserving the dynamic aperture. This novel approach promises to reduce particle losses and enable order-of-magnitude increases in beam intensity. In this paper we present results, obtained using the Lie operator formalism, on how chromaticity and dispersion affect particle orbits in integrable optics. We conclude that chromaticity in general breaks the integrability, unless the vertical and horizontal chromaticities are equal. Because of this, the chromaticity correcting magnets can be weaker and fewer correcting magnet families are required, thus minimizing the impact on dynamic aperture.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Theoretical Approach Of The Reduction Of Chromatic And Spherical Aberrations In An Acceleration Lens System For Hundreds Of keV Gaseous Ion Nanobeam

The focused gaseous ion beam (gas-FIB) system composed of a series of electrostatic lenses, called ''acceleration lens system'', has been developed to form nanobeams using gaseous ions generated from a plasma ion source. Ion beams are accelerated and focused simultaneously by a pair of electrodes. A new all-in-one compact acceleration system including an acceleration tube is now under development to form 300 keV ion nanobeam. Chromatic and spherical aberrations are, however, hindrance to form nanobeams with their smaller sizes in diameter. A deceleration lens, which performs like a defocusing lens, was theoretically introduced to downstream of the present acceleration lens system to reduce the aberrations. Ion beam optics simulations were carried out to show that this aberration reduction technique is effective to reduce chromatic and spherical aberrations. As a result, we reduced the chromatic aberration coefficient by 26%, the spherical aberration coefficient by 17% and a beam diameter by 17%, with the deceleration energy of 15 keV. In case of using an electrostatic acceleration tube with 100 mm length, the final beam diameter of 103 nm at 300 keV is obtained by the all-in-one acceleration lens system with the total acceleration length of only 650 mm.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site - Part 2

At the Hanford Site, chromate was used throughout the 100 Areas (100-B, 100-C, 100-D/DR, 100-F, 100-H, and 100 K) as a corrosion inhibitor in reactor cooling water. Chromate was delivered in rail cars, tanker trucks, barrels, and local pipelines as dichromate granular solid or stock solution. In many occasions, chromate was inevitably discharged to surface or near-surface ground through spills during handling, pipeline leaks, or during disposal to cribs. The composition of the liquids that were discharged is not known and it is quite possible that Cr(VI) fate and transport in the contaminated sediments would be a function of the chemical composition of the waste fluids. The major objectives of this investigation which was limited in scope by the financial resources available, were to 1) determine the leaching characteristics of hexavalent chromium [Cr(VI)] from contaminated sediments collected from 100-D Area spill sites; 2) elucidate possible Cr(VI) mineral and/or chemical associations that may be responsible for Cr(VI) retention in the Hanford Site 100 Areas through the use of macroscopic leaching studies, and microscale characterization of contaminated sediments; and 3) provide information to construct a conceptual model of Cr(VI) geochemistry in the Hanford 100 Area vadose zone that can be used for developing options for environmental remediation. The information gathered from this research effort will help to further improve our understanding of Cr(VI) behavior in the vadose zone and will also help in accelerating the 100 Area Columbia River Corridor cleanup by providing valuable information to develop remedial action based on a fundamental understanding of Cr(VI) vadose zone geochemistry. A series of column experiments were conducted with contaminated sediments to study Cr(VI) desorption patterns. Column experiments used the field size fraction of the sediment samples and a simulated Hanford Site groundwater solution. Periodic stop flow events were applied to evaluate the change in elemental concentration during time periods of no flow and greater fluid residence time. Sediments were characterized for the spatial and mineralogical associations of the contamination using some microscale techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Mössbauer spectroscopy.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Influences of wide-angle and multi-beam interference on the chromaticity and efficiency of top-emitting white organic light-emitting diodes

Wide-angle interference (WI) and multi-beam interference (MI) in microcavity are analyzed separately to improve chromaticity and efficiency of the top-emitting white organic light-emitting diodes (TWOLEDs). A classic electromagnetic theory is used to calculate the resonance intensities of WI and MI in top-emitting organic light-emitting diodes (TOLEDs) with influence factors (e.g., electrodes and exciton locations) being considered. The role of WI on the performances of TOLEDs is revealed through using δ-doping technology and comparing blue and red EML positions in top-emitting and bottom-emitting devices. The blue light intensity significantly increases and the chromaticity of TWOLEDs is further improved with the use of enhanced WI (the blue emitting layer moving towards the reflective electrode) in the case of a weak MI. In addition, the effect of the thicknesses of light output layer and carrier transport layers on WI and MI are also investigated. Apart from the microcavity effect, other factors, e.g., carrier balance and carrier recombination regions are considered to obtain TWOLEDs with high efficiency and improved chromaticity near white light equal-energy point.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Chromatic annuli formation and sample oxidation on copper thin films by femtosecond laser

We report an experimental investigation on the irradiation of copper thin films with high repetition rate femtosecond laser pulses (1040 nm, 50 MHz), in ambient air and liquid water. We observe a novel, striking phenomenon of chromatic copper oxides (CuO and Cu{sub 2}O) annuli generation. The characteristic features of the chromatic copper oxide annuli are studied by exploiting micro-Raman spectroscopy, optical and scanning electron microscopies. In the case of irradiation in water, the seldom investigated effects of the immersion time, t{sub w}, after irradiation with a fixed number of pulses are analyzed, and an intriguing dependence of the color of the chromatic annuli on t{sub w} is observed. This remarkable behavior is explained by proposing an interpretation scenario addressing the various processes involved in the process. Our experimental findings show that Cu{sub 2}O nanoparticles (size of ≈20 nm) and Cu{sub 2}O nanocubes (nanocube edges of ≈30, ≈60 nm) can be effectively generated by exploiting high repetition rate laser-assisted oxidation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Obstructions to the realization of distance graphs with large chromatic numbers on spheres of small radii

We investigate in detail some properties of distance graphs constructed on the integer lattice. Such graphs find wide applications in problems of combinatorial geometry, in particular, such graphs were employed to answer Borsuk's question in the negative and to obtain exponential estimates for the chromatic number of the space. This work is devoted to the study of the number of cliques and the chromatic number of such graphs under certain conditions. Constructions of sequences of distance graphs are given, in which the graphs have unit length edges and contain a large number of triangles that lie on a sphere of radius 1/√3 (which is the minimum possible). At the same time, the chromatic numbers of the graphs depend exponentially on their dimension. The results of this work strengthen and generalize some of the results obtained in a series of papers devoted to related issues. Bibliography: 29 titles.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Widening and distortion of the particle energy distribution by chromaticity in quasi-isochronous rings

This paper reports the observation of beam energy widening and distortion from Gaussian due to a nonvanishing horizontal chromaticity at a quasi-isochronous storage ring. The result originates from an average path-length dependence on the betatron oscillation amplitudes, which is intimately correlated to the transverse chromaticities. It is the first experimental validation of the impact of such a nonlinear transverse-longitudinal coupling effect on the equilibrium beam characteristics in a storage ring. The results could be important for quasi-isochronous rings, steady-state microbunching, nonscaling fixed-field alternate gradient accelerators, etc., where very small momentum compaction or large chromaticity is required.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Local chromatic correction optics for Future Circular Collider e + e −

Local chromatic correction optics are proposed for the Future Circular e + − e − Collider. These new optics assume an identical layout of the magnets at all operation energies and include a new design for the arcs, for the straight sections, and for the final focus. The arcs design is a step forward from the classic FODO lattice that achieves near cancellation up to the fourth order of chromatic and geometric aberrations. Straight sections and the final focus benefit from the application of transparency conditions and are thus minimally impacting the global beam dynamics. The final focus design includes both vertical and horizontal chromaticity correction sections, crab sextupoles, and additional specific sextupoles and decapoles for the optimization of the dynamics off-energy. Decapoles are very effective in mitigating the reduction of dynamic aperture due to synchrotron radiation. Nonlinear magnet settings are further optimized with multiobjective algorithms. The overall properties of the new optics proposed are analyzed in the presence of errors and compared to other optics designs.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Explicit formulas for 2nd-order driving terms due to sextupoles and chromatic effects of quadrupoles

Optimization of nonlinear driving terms have become a useful tool for designing storage rings, especially modern light sources where the strong nonlinearity is dominated by the large chromatic effects of quadrupoles and strong sextupoles for chromaticity control. The Lie algebraic method is well known for computing such driving terms. However, it appears that there was a lack of explicit formulas in the public domain for such computation, resulting in uncertainty and/or inconsistency in widely used codes. This note presents explicit formulas for driving terms due to sextupoles and chromatic effects of quadrupoles, which can be considered as thin elements. The computation is accurate to the 4th-order Hamiltonian and 2nd-order in terms of magnet parameters. The results given here are the same as the APS internal note AOP-TN-2009-020. This internal nte has been revised and published here as a Light Source Note in order to get this information into the public domain, since both ELEGANT and OPA are using these formulas.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Corrosion Behavior of Laser-Interference Structured AA2024 Coated with a Chromate-Containing Epoxy Primer

In this study, the corrosion behavior of laser-interference treated AA2024-T3 specimens, which are coated with a primer, is presented. The surface of as-received AA2024-T3 specimens were laser-interference structured by splitting the primary beam of a Q-switched Nd:YAG pulsed nanosecond laser into two beams and focusing them to the same spot on the specimen surface. After being stored in plastic cases for up to 70 d, without any additional cleaning, the specimens were spray painted with a chromate-containing epoxy primer, CA7233, compliant to MIL-PRF-23377 Type I Class C2 specification. The corrosion behavior of laser-interference specimens was assessed against that of specimens prepared by chromated conversion coating and sulfuric acid anodizing treatments. After the ASTM B117 corrosion exposure, it was found that the laser processed specimens exhibited only few blisters. On one hand, most specimens prepared at a laser fluence of 1.78 J/cm 2 , without any additional chemical cleaning, were found to develop one very small blister after only 96 h of exposure. However, the growth of these blisters was not significant even after 1,000 h of salt spray exposure. On the other hand, only a fraction of the specimens prepared at a laser fluence of 1.24 J/cm 2 and acetone wiped right after the laser structuring were found to develop several tiny blisters after 790 h and longer exposure. Overall, it was found that the corrosion damage was minimized at a laser rastering speed of 4 mm/s, a condition for which only 33% of specimens developed very minor corrosion damage. Furthermore, the ASTM D1654 creepage ratings, which was used to evaluate the corrosion damage along the scribe lines, were found to be at least nine for all coated panels. These results indicate that the laser-interference technique with the additional acetone wiping has the potential to be further developed as a nonchemical surface preparation technique for chromate-containing epoxy primers coating systems.

36 MATERIALS SCIENCE↗
NASA NTRS2008

Chromatic Modulator for a High-Resolution CCD or APS

A chromatic modulator has been proposed to enable the separate detection of the red, green, and blue (RGB) color components of the same scene by a single charge-coupled device (CCD), active-pixel sensor (APS), or similar electronic image detector. Traditionally, the RGB color-separation problem in an electronic camera has been solved by use of either (1) fixed color filters over three separate image detectors; (2) a filter wheel that repeatedly imposes a red, then a green, then a blue filter over a single image detector; or (3) different fixed color filters over adjacent pixels. The use of separate image detectors necessitates precise registration of the detectors and the use of complicated optics; filter wheels are expensive and add considerably to the bulk of the camera; and fixed pixelated color filters reduce spatial resolution and introduce color-aliasing effects. The proposed chromatic modulator would not exhibit any of these shortcomings. The proposed chromatic modulator would be an electromechanical device fabricated by micromachining. It would include a filter having a spatially periodic pattern of RGB strips at a pitch equal to that of the pixels of the image detector. The filter would be placed in front of the image detector, supported at its periphery by a spring suspension and electrostatic comb drive. The spring suspension would bias the filter toward a middle position in which each filter strip would be registered with a row of pixels of the image detector. Hard stops would limit the excursion of the spring suspension to precisely one pixel row above and one pixel row below the middle position. In operation, the electrostatic comb drive would be actuated to repeatedly snap the filter to the upper extreme, middle, and lower extreme positions. This action would repeatedly place a succession of the differently colored filter strips in front of each pixel of the image detector. To simplify the processing, it would be desirable to encode information on the color of the filter strip over each row (or at least over some representative rows) of pixels at a given instant of time in synchronism with the pixel output at that instant.

Hartley, Frank↗
DOE OSTI2012

Recycler Chromaticities and End Shims for NOvA at Fermilab

In era of NOvA operation, it is planned to slip-stack six on six Booster proton batches in the Recycler ring for a total intensity of 5 x 10{sup 13} protons/cycle. During the slip-stacking, the chromaticities are required to be jumped from (-2,-2) to (-20,-20). However, with the existing 2 families of powered sextupoles in the lattice, the chromaticities can only be adjusted to (-12,-12) from (-2,-2). On the other hand, the presently designed Recycler lattice for Nova replaces the 30 straight section with 8 'D-D half FODO cells'. With the limit of the feasible quad strength, 3 quads in a half-cell were used to obtain the working point under, and the maximum beta-functions in this section cannot be less than 80 m. In this paper, we re-designed the end shims of the permanent magnets in the ring lattice with appropriate quadrupole and sextupole components to meet both chromaticity and tune requirements. We are able to use 2 quads in a half cell in RR30 straight section within feasible quad strength. The maximum beta-functions are also lowered to around 55 m. The dynamic aperture tracking has been done using MAD to simulate the scenario of beam injection into the Recycler ring for Nova.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Traverse Focusing of Intense Charged Particle Beams with Chromatic Effects for Heavy Ion Fusion

A fi nal focusing scheme designed to minimize chromatic effects is discussed. The Neutralized Drift Compression Experiment-II (NDCX-II) will apply a velocity tilt for longitudinal bunch compression, and a fi nal focusing solenoid (FFS) for transverse bunch compression. In the beam frame, neutralized drift compression causes a suffi ciently large spread in axial momentum, pz , resulting in chromatic effects to the fi nal focal spot during transverse bunch compression. Placing a weaker solenoid upstream of a stronger fi nal focusing solenoid (FFS) mitigates chromatic effects and improves transverse focusing by a factor of approximately 2-4 for appropriate NDCX-II parameters.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Analytic Chromaticity Formulas for the Muon g -2 experiment at fermilab

The Muon g-2 Experiment (E989) at Fermilab measured the muon anomalous magnetic moment aμ with unprecedented precision of 127 ppb using a storage ring. The experiment pushed the limits in terms of accuracy and systematic errors. Achieving the 78-ppb total systematic uncertainty required precise beam dynamics modeling and corrections for effects on the measured muon precession frequency. Here, we derived the first analytic aberration formulas up to the second order for the muon g-2 storage ring’s combined-function electrostatic quadrupoles (superimposed magnetic dipole and electric quadrupole fields) using an order-by-order perturbation method. From these, we obtained the exact chromaticity formulas for three ring models of different granularity and validated them against numerical calculations using COSY INFINITY, achieving analytic-numerical agreement to ⁠$\mathscr{O}(10^{-10})$. This work resolved discrepancies between previous approximate derivations and provided essential beam dynamics results for Runs 4-6 analyses. We also calculated nonlinear chromaticities up to ninth order. The experiment completed its final Run 6 in July 2023, collecting 21 times more data than the previous muon g-2 experiment at Brookhaven National Laboratory, with the final result announced in June 2025.

aberrations↗
DOE OSTI2019

Influence of Time-of-Flight Chromatic Aberration on the Dynamics of Propagation of Pulsed Electron Beam in Ultrafast Electron Microscopy: A New Strategy for Better Temporal Resolution

A common strategy aimed at achieving a high temporal resolution in ultrafast electron microscopy and diffraction is based on the use of strong electrostatic fields in the accelerating gap to form fast electron pulses of ultrashort duration. In this work, the dynamics of the propagation of ultrashort photoelectron bunches is studied taking into account the time-of-flight chromatic aberration: the spread-out of electron pulses at the exit from the region of the accelerating electric field. The results of the calculation of the duration of photoelectron pulses taking into account Coulomb repulsion are presented. According to the analysis, the use of strong electrostatic fields in the accelerating gap for the formation of fast electron pulses of ultrashort duration is not a necessary condition for achieving the final high temporal resolution in the method of ultrafast electron microscopy. The modes of operation of ultrafast transmission electron microscope were found for which the temporal resolution increases with the growth of time-of-flight chromatic aberration.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Complete genome sequence of the chromate-reducing bacterium Thermoanaerobacter thermohydrosulfuricus strain BSB-33

Thermoanaerobacter thermohydrosulfuricus BSB-33 is a thermophilic gram positive obligate anaerobe isolated from a hot spring in West Bengal, India. Unlike other T. thermohydrosulfuricus strains, BSB-33 is able to anaerobically reduce Fe(III) and Cr(VI) optimally at 60 °C. BSB-33 is the first Cr(VI) reducing T. thermohydrosulfuricus genome sequenced and of particular interest for bioremediation of environmental chromium contaminations. Here we discuss features of T. thermohydrosulfuricus BSB-33 and the unique genetic elements that may account for the peculiar metal reducing properties of this organism. The T. thermohydrosulfuricus BSB-33 genome comprises 2597606 bp encoding 2581 protein genes, 12 rRNA, 193 pseudogenes and has a G + C content of 34.20 %. Lastly, putative chromate reductases were identified by comparative analyses with other Thermoanaerobacter and chromate-reducing bacteria.

Bioremediation↗