Synchrotron X-Ray Measurement of Direct Injection Gasoline Fuel Sprays

2001 ◽  
Author(s):  
Y. Yue ◽  
C. Powell ◽  
R. Cuenca ◽  
R. Poola ◽  
J. Wang
Keyword(s):  
Visible Light ◽  
Volume Fraction ◽  
Direct Injection ◽  
X Rays ◽  
Hollow Cone ◽  
Optical Techniques ◽  
Time Resolved ◽  
X Ray ◽  
Direct Measurements ◽  
Strong Asymmetry

Abstract A quantitative and time-resolved radiographic has been used to characterize direct-injection (Dl) gasoline sprays in near-nozzle region. The highly penetrative nature of x-rays promises the direct measurements of dense sprays that are difficult to study by visible-light optical techniques. Appropriate models were developed to determine the fuel volume fraction as a function of time and positions. The results also show quantitatively the strong asymmetry of the hollow-cone sprays studied here.

Quantitative X-Ray Measurements of Diesel Spray Cores

2001 ◽  
Author(s):  
Christopher F. Powell ◽  
Yong Yue ◽  
Jin Wang ◽  
Ming-Chia Lai ◽  
Johannes Schaller
Keyword(s):  
Volume Fraction ◽  
Combustion Process ◽  
Argonne National Laboratory ◽  
Pollutant Emissions ◽  
Detailed Knowledge ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Fuel Sprays ◽  
Quantitative Measurements

Abstract A detailed knowledge of the fuel injection process is recognized as a key to the design of clean-burning and efficient combustion engines. As standards for pollutant emissions are tightened worldwide, such knowledge becomes more critical. Computer modeling of the combustion process relies on accurate measurements of the spray throughout its lifetime, and in particular knowledge of the near-nozzle region of the spray is of great importance. A number of techniques have been developed to study the properties of fuel sprays. However, all of these techniques are significantly limited in the region near the nozzle of high-pressure sprays. No mechanical or visible light probe is able to make non-intrusive and quantitative measurements of the spray in this region. We have been developing techniques to study sprays using synchrotron x-rays from the Advanced Photon Source at Argonne National Laboratory. We are using an intense, monochromatic x-ray beam as a probe to make time-resolved, quantitative measurements, of intermittent fuel sprays. These experiments have demonstrated that x-rays overcome many of the limitations of other techniques, allowing quantitative characterization of the spray with high time and position resolution. The x-ray technique enables us to make a time-resolved mapping of the mass distribution near the spray nozzle, even immediately adjacent to the orifice. With such a mapping of the mass a number of spray characteristics can be determined, such as the fuel volume fraction, the injection rate and total mass, the speed of the leading and trailing edges of the spray, etc. These quantitative measurements should allow more realistic computational modeling of sprays with better predictive power.

Studies of metaphase chromosomes in the scanning transmission x-ray microscope: Image fidelity, radiation damage and specimen preparation

1992 ◽  
Vol 50 (2) ◽  
pp. 1038-1039
Author(s):  
Shawn Williams ◽  
Xiaodong Zhang ◽  
Susan Lamm ◽  
Jack Van’t Hof
Keyword(s):  
Visible Light ◽  
Radiation Damage ◽  
Cross Section ◽  
Imaging Techniques ◽  
Dose Range ◽  
Specimen Preparation ◽  
X Rays ◽  
Metaphase Chromosomes ◽  
X Ray ◽  
Scanning Transmission

The Scanning Transmission X-ray Microscope (STXM) is well suited for investigating metaphase chromosome structure. The absorption cross-section of soft x-rays having energies between the carbon and oxygen K edges (284 - 531 eV) is 6 - 9.5 times greater for organic specimens than for water, which permits one to examine unstained, wet biological specimens with resolution superior to that attainable using visible light. The attenuation length of the x-rays is suitable for imaging micron thick specimens without sectioning. This large difference in cross-section yields good specimen contrast, so that fewer soft x-rays than electrons are required to image wet biological specimens at a given resolution. But most imaging techniques delivering better resolution than visible light produce radiation damage. Soft x-rays are known to be very effective in damaging biological specimens. The STXM is constructed to minimize specimen dose, but it is important to measure the actual damage induced as a function of dose in order to determine the dose range within which radiation damage does not compromise image quality.

Mesoscopic structure of SiC fibers by neutron and x-ray scattering

1996 ◽  
Vol 11 (5) ◽  
pp. 1169-1178 ◽  
Author(s):  
Kentaro Suzuya ◽  
Michihiro Furusaka ◽  
Noboru Watanabe ◽  
Makoto Osawa ◽  
Kiyohito Okamura ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Volume Fraction ◽  
X Rays ◽  
X Ray ◽  
Sic Fibers ◽  
X Ray Scattering ◽  
Mesoscopic Structure ◽  
Angle Scattering ◽  
Momentum Transfer Range ◽  
First Time

Mesoscopic structures of SiC fibers produced from polycarbosilane by different methods were studied by diffraction and small-angle scattering of neutrons and x-rays. Microvoids of a size of 4–10 Å in diameter have been observed for the first time by neutron scattering in a medium momentum transfer range (Q = 0.1–1.0 Å−1). The size and the volume fraction of β–SiC particles were determined for fibers prepared at different heat-treatment temperatures. The results show that wide-angle neutron scattering measurements are especially useful for the study of the mesoscopic structure of multicomponent materials.

Structural dynamics of PZT thin films at the nanoscale

2005 ◽  
Vol 902 ◽  
Author(s):  
Alexei Grigoriev ◽  
Dal-Hyun Do ◽  
Dong Min Kim ◽  
Chang-Beom Eom ◽  
Bernhard Adams ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Lattice Distortion ◽  
Piezoelectric Effect ◽  
Polarization Switching ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Converse Piezoelectric Effect ◽  
Ferroelectric Capacitors ◽  
Crystal Lattice Distortion

AbstractWhen an electric field is applied to a ferroelectric the crystal lattice spacing changes as a result of the converse piezoelectric effect. Although the piezoelectric effect and polarization switching have been investigated for decades there has been no direct nanosecond-scale visualization of these phenomena in solid crystalline ferroelectrics. Synchrotron x-rays allow the polarization switching and the crystal lattice distortion to be visualized in space and time on scales of hundreds of nanometers and hundreds of picoseconds using ultrafast x-ray microdiffraction. Here we report the polarization switching visualization and polarization domain wall velocities for Pb(Zr0.45Ti0.55)O3 thin film ferroelectric capacitors studied by time-resolved x-ray microdiffraction.

X-ray Microscopy in your Lab

2013 ◽  
Vol 21 (2) ◽  
pp. 7-7
Author(s):  
Charles Lyman
Keyword(s):  
Grain Size ◽  
Point Source ◽  
Visible Light ◽  
Light Microscope ◽  
Construction Materials ◽  
X Rays ◽  
X Ray ◽  
Projection Images ◽  
Straight Lines

Using X rays to produce magnified images of objects has been a goal for 150 years. Ever since Ernst Abbe declared in 1873 that light microscope resolution was limited by the wavelength of light, the search was on for a microscopy medium with a wavelength shorter than visible light (<500 nm). When Roentgen discovered X rays in 1895, it was thought that the new medium may have been found. Soon it was clear, however, that it was not easy to construct a physical lens for X rays because the rays penetrated all lens construction materials. X-ray “radiography images” of a few times magnification were possible but only as projection images, formed as X rays from millimeter-sized sources traveled in straight lines through the specimen to be captured on film. Unfortunately, even in the best cases, useful magnification was limited by the relatively large “point source” of X rays and the large grain size of X-ray film (both about 0.1–1.0 mm).

scholarly journals Time-Resolved Macromolecular Crystallography at Pulsed X-ray Sources

2019 ◽  
Vol 20 (6) ◽  
pp. 1401 ◽  
Author(s):  
Marius Schmidt
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Reaction Dynamics ◽  
X Rays ◽  
Free Electron Lasers ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
X Ray ◽  
Methodological Aspects

The focus of structural biology is shifting from the determination of static structures to the investigation of dynamical aspects of macromolecular function. With time-resolved macromolecular crystallography (TRX), intermediates that form and decay during the macromolecular reaction can be investigated, as well as their reaction dynamics. Time-resolved crystallographic methods were initially developed at synchrotrons. However, about a decade ago, extremely brilliant, femtosecond-pulsed X-ray sources, the free electron lasers for hard X-rays, became available to a wider community. TRX is now possible with femtosecond temporal resolution. This review provides an overview of methodological aspects of TRX, and at the same time, aims to outline the frontiers of this method at modern pulsed X-ray sources.

scholarly journals Experimental and numerical study of ultra-short laser-produced collimated Cu Kα X-ray source

2017 ◽  
Vol 35 (3) ◽  
pp. 442-449 ◽  
Author(s):  
R. Rathore ◽  
V. Arora ◽  
H. Singhal ◽  
T. Mandal ◽  
J.A. Chakera ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Numerical Study ◽  
Low Cost ◽  
Laser Pulses ◽  
Photon Flux ◽  
X Rays ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Short Laser Pulses

AbstractKα X-ray sources generated from the interaction of ultra-short laser pulses with solids are compact and low-cost source of ultra-short quasi-monochromatic X-rays compared with synchrotron radiation source. Development of collimated ultra-short Kα X-ray source by the interaction of 45 fs Ti:sapphire laser pulse with Cu wire target is presented in this paper. A study of the Kα source with laser parameters such as energy and pulse duration was carried out. The observed Kα X-ray photon flux was ~2.7 × 108 photons/shot at the laser intensity of ~2.8 × 1017 W cm−2. A model was developed to analyze the observed results. The Kα radiation was coupled to a polycapillary collimator to generate a collimated low divergence (0.8 mrad) X-ray beam. Such sources are useful for time-resolved X-ray diffraction and imaging studies.

Time-Resolved X-ray Shadowgraphy Experiment of Laser Ablation of Aluminum using Laser-Induced Picosecond Pulsed X-rays

1999 ◽  
Vol 38 (Part 2, No. 3A) ◽  
pp. L242-L244 ◽  
Author(s):  
Yoichiro Hironaka ◽  
Tomoharu Inoue ◽  
Yasushi Fujimoto ◽  
Kazutaka G. Nakamura ◽  
Ken-ichi Kondo ◽  
...  
Keyword(s):  
Laser Ablation ◽  
X Rays ◽  
Time Resolved ◽  
X Ray

scholarly journals Measurements of the ablation-front trajectory and low-mode nonuniformity in direct-drive implosions using x-ray self-emission shadowgraphy

2015 ◽  
Vol 3 ◽  
Author(s):  
D.T. Michel ◽  
A.K. Davis ◽  
W. Armstrong ◽  
R. Bahr ◽  
R. Epstein ◽  
...  
Keyword(s):  
Plasma Phys ◽  
X Rays ◽  
Direct Drive ◽  
Time Resolved ◽  
X Ray ◽  
Laser Facility ◽  
Omega Laser ◽  
Control Fusion ◽  
Pm 10 ◽  
Ablation Front

Self-emission x-ray shadowgraphy provides a method to measure the ablation-front trajectory and low-mode nonuniformity of a target imploded by directly illuminating a fusion capsule with laser beams. The technique uses time-resolved images of soft x-rays ( ${>}1$  keV) emitted from the coronal plasma of the target imaged onto an x-ray framing camera to determine the position of the ablation front. Methods used to accurately measure the ablation-front radius ( ${\it\delta}R=\pm 1.15~{\rm\mu}\text{m}$ ), image-to-image timing ( ${\it\delta}({\rm\Delta}t)=\pm 2.5$  ps) and absolute timing ( ${\it\delta}t=\pm 10$  ps) are presented. Angular averaging of the images provides an average radius measurement of ${\it\delta}(R_{\text{av}})=\pm 0.15~{\rm\mu}\text{m}$ and an error in velocity of ${\it\delta}V/V=\pm 3\%$ . This technique was applied on the Omega Laser Facility [Boehly et al., Opt. Commun. 133, 495 (1997)] and the National Ignition Facility [Campbell and Hogan, Plasma Phys. Control. Fusion 41, B39 (1999)].

scholarly journals Creating flat-top X-ray beams by applying surface profiles of alternating curvature to deformable piezo bimorph mirrors

2016 ◽  
Vol 23 (6) ◽  
pp. 1333-1347 ◽  
Author(s):  
John P. Sutter ◽  
Simon G. Alcock ◽  
Yogesh Kashyap ◽  
Ioana Nistea ◽  
Hongchang Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Surface Modifications ◽  
X Rays ◽  
X Ray ◽  
Optical Surfaces ◽  
Surface Errors ◽  
Surface Profiles ◽  
Active Mirrors ◽  
Non Gaussian ◽  
First Time

Beam shaping is becoming increasingly important for synchrotron X-ray applications. Although routine for visible light lasers, this is challenging for X-rays due to the limited source coherence and extreme optical tolerances required for the shaping mirrors. In deliberate defocusing, even surface errors <5 nm r.m.s. introduce damagingly large striations into the reflected beam. To counteract such problems, surface modifications with alternating concave and convex curvature on equal segments were polished onto the surface of non-active mirrors of fixed curvature. Such optics are useful for providing a fixed size of X-ray beam, but do not provide the adaptability required by many experiments. In contrast, deformable piezo bimorph mirrors permit a continuous range of X-ray beam sizes and shapes. A new theory is developed for applying non-periodic modifications of alternating curvature to optical surfaces. The position and length of the segments may be freely chosen. For the first time, surface modifications of alternating curvature are applied to bimorph mirrors to generate non-Gaussian X-ray beam profiles of specified width. The new theory's freedom is exploited to choose the segments to match the polishing errors of medium wavelength (>10 mm) and the piezos' influence on the mirror's figure. Five- and seven-segment modifications of alternating curvature are calculated and verified by visible light and X-ray metrology. The latter yields beam profiles with less striation than those made by defocusing. Remaining beam striations are explained by applying geometrical optics to the deviations from the ideal surface modifications of alternating curvature.

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