Science.gov

Sample records for ion detachment processes

  1. Electron collisional detachment processes for a 250 keV D/sup -/ ion beam in a partially ionized hydrogen target

    SciTech Connect

    Savas, S.E.

    1980-09-01

    Neutral atom beams with energies above 200 keV may be required for various purposes in magnetic fusion devices following TFTR, JET and MFTF-B. These beams can be produced much more efficiently by electron detachment from negative ion beams than by electron capture by positive ions. We have investigated the efficiency with which such neutral atoms can be produced by electron detachment in partially ionized hydrogen plasma neutralizers.

  2. Mutual electron detachment in collisions between negative ions

    NASA Astrophysics Data System (ADS)

    Schulze, R.; Melchert, F.; Krüdener, S.; Meuser, S.; Petri, S.; Benner, M.; Salzborn, E.

    1992-10-01

    Employing the crossed-beams technique, we have measured absolute cross sections for mutual electron detachment in collisions between two negative ions H-+X-→H0+X0+2e-(X-:B-, H-,Cu-,O-,Au-,F-) in the CM-energy range between a few keV and about 100 keV. The results obtained appear not to obey a simple scaling with negative ion binding energies. For H-+H--collisions also the single detachment reaction H-+H-→H0+... has been investigated.

  3. Divertor detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, Sergei

    2015-11-01

    The heat exhaust is one of the main conceptual issues of magnetic fusion reactor. In a standard operational regime the large heat flux onto divertor target reaches unacceptable level in any foreseeable reactor design. However, about two decades ago so-called ``detached divertor'' regimes were found. They are characterized by reduced power and plasma flux on divertor targets and look as a promising solution for heat exhaust in future reactors. In particular, it is envisioned that ITER will operate in a partly detached divertor regime. However, even though divertor detachment was studied extensively for two decades, still there are some issues requiring a new look. Among them is the compatibility of detached divertor regime with a good core confinement. For example, ELMy H-mode exhibits a very good core confinement, but large ELMs can ``burn through'' detached divertor and release large amounts of energy on the targets. In addition, detached divertor regimes can be subject to thermal instabilities resulting in the MARFE formation, which, potentially, can cause disruption of the discharge. Finally, often inner and outer divertors detach at different plasma conditions, which can lead to core confinement degradation. Here we discuss basic physics of divertor detachment including different mechanisms of power and momentum loss (ionization, impurity and hydrogen radiation loss, ion-neutral collisions, recombination, and their synergistic effects) and evaluate the roles of different plasma processes in the reduction of the plasma flux; detachment stability; and an impact of ELMs on detachment. We also evaluate an impact of different magnetic and divertor geometries on detachment onset, stability, in- out- asymmetry, and tolerance to the ELMs. Supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences under Award Number DE-DE-FG02-04ER54739 at UCSD.

  4. High-energy above-threshold detachment from negative ions

    SciTech Connect

    Gazibegovic-Busuladzic, A.; Milosevic, D.B.; Becker, W.

    2004-11-01

    Above-threshold detachment of electrons from negative ions by an elliptically polarized laser field is analyzed within the strong-field approximation. The low-energy part of the spectrum, that is, its structure and its apparent cutoff, strongly depends on the orbital quantum number l of the initial ground state. The high-energy part is characterized by the usual extended plateau caused by rescattering, which is essentially independent of the ground state. The potential that the returning electron experiences during rescattering is modeled by the sum of a polarization potential and a static potential. This rescattering potential does not have much effect on the shape of the plateau, but it does on its height. For H{sup -} (l=0), the yield of rescattered electrons is five orders of magnitude below the direct electrons, while for I{sup -} (l=1) the yields only differ by a factor of 40. We also analyze the dependence of the angle-resolved energy spectrum on the ellipticity of the laser field and confirm general symmetry properties. An angle-integrated elliptic dichroism parameter is introduced and analyzed.

  5. Experimental studies on ion acceleration and stream line detachment in a diverging magnetic field

    PubMed Central

    Terasaka, K.; Yoshimura, S.; Ogiwara, K.; Aramaki, M.; Tanaka, M. Y.

    2010-01-01

    The flow structure of ions in a diverging magnetic field has been experimentally studied in an electron cyclotron resonance plasma. The flow velocity field of ions has been measured with directional Langmuir probes calibrated with the laser induced fluorescence spectroscopy. For low ion-temperature plasmas, it is concluded that the ion acceleration due to the axial electric field is important compared with that of gas dynamic effect. It has also been found that the detachment of ion stream line from the magnetic field line takes place when the parameter |fciLB∕Vi| becomes order unity, where fci, LB, and Vi are the ion cyclotron frequency, the characteristic scale length of magnetic field inhomogeneity, and the ion flow velocity, respectively. In the detachment region, a radial electric field is generated in the plasma and the ions move straight with the E×B rotation driven by the radial electric field. PMID:20838424

  6. Model for electron detachment from negative ions by ultrashort half-cycle electric-field pulses

    NASA Astrophysics Data System (ADS)

    Grozdanov, T. P.; Jaćimović, J.

    2009-01-01

    We study a model for electron detachment from negative ions by ultrashort unipolar electric pulses. The electron-atom interaction is described by the zero-range potential and the temporal dependence of the electric field is approximated by the Dirac δ functions. The case of a single pulse can be treated semianalytically and explicit expressions are obtained for momentum and energy distributions of detached electrons as well as for the total detachment probability. The determination of angular distribution involves numerical evaluation of a one-dimensional integral. The case of two alternating electric pulses requires numerical evaluation of more complicated integrals but leads to interesting effects caused by the quantum interference of the electronic wave packets produced during the interactions with the first and the second pulses. The differential and integral detachment probabilities are calculated and discussed for a variety of pulse strengths and time delays between the pulses.

  7. A geomorphic process law for detachment-limited hillslopes

    NASA Astrophysics Data System (ADS)

    Turowski, Jens

    2015-04-01

    Geomorphic process laws are used to assess the shape evolution of structures at the Earth's surface over geological time scales, and are routinely used in landscape evolution models. There are two currently available concepts on which process laws for hillslope evolution rely. In the transport-limited concept, the evolution of a hillslope is described by a linear or a non-linear diffusion equation. In contrast, in the threshold slope concept, the hillslope is assumed to collapse to a slope equal to the internal friction angle of the material when the load due to the relief exists the material strength. Many mountains feature bedrock slopes, especially in the high mountains, and material transport along the slope is limited by the erosion of the material from the bedrock. Here, I suggest a process law for detachment-limited or threshold-dominated hillslopes, in which the erosion rate is a function of the applied stress minus the surface stress due to structural loading. The process law leads to the prediction of an equilibrium form that compares well to the shape of many mountain domes.

  8. Dielectric breakdown properties of N2-O2 mixtures by considering electron detachments from negative ions

    NASA Astrophysics Data System (ADS)

    Zhao, Hu; Lin, Hui

    2016-07-01

    The paper analyzes the dielectric breakdown properties of N2-O2 mixtures at different O2 concentrations and gas pressures, taking into account electron detachments from negative ions. The reduced effective ionization coefficients α(eff)/N in N2-O2 mixtures at different O2 concentrations and gas pressures were calculated and analyzed, by considering electron detachments. The critical reduced electric fields (E/N)cr and the critical electron temperature Tb were then determined. The result indicates a clear enhancement of α(eff)/N by collisional detachments, which causes a reduction in the (E/N)cr. In addition, a synergistic effect in the N2-O2 mixture was also observed in both (E/N)cr and Tb. The value of Tb was decreased by the increase of pd product, however, Tb tended to be constant at relatively high pd products.

  9. Over-the-barrier electron detachment in the hydrogen negative ion

    NASA Astrophysics Data System (ADS)

    Milošević, M. Z.; Simonović, N. S.

    2016-09-01

    The electron detachment from the hydrogen negative ion in strong fields is studied using the two-electron and different single-electron models within the quasistatic approximation. Special attention is payed to over-the-barrier regime where the Stark saddle is suppressed below the lowest energy level. It is demonstrated that the single-electron description of the lowest state of the ion, that is a good approximation for weak fields, fails in this and partially in the tunnelling regime. The exact lowest state energies and detachment rates for the ion at different strengths of the applied field are determined by solving the eigenvalue problem of the full two-electron Hamiltonian. A simple formula for the rate, which is valid in both regimes, is determined by fitting the exact data to the expression estimated using single-electron descriptions.

  10. The Detached Bridgman Process: Application for the Growth of Low-Defect Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Croell, A.; Dold, P.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    During crystal growth in the vertical Bridgman process, both the melt and the growing crystal are in contact with the ampoule wall. The different thermal coefficients of expansion of the crystal and the ampoule wall can lead to stresses, crystal defects, and not rarely to cracks and/or polycrystalline growth in the crystal. The detached Bridgman process is characterized by the fact that the melt meniscus frees itself from the ampoule wall and the crystal can be grown without wall contact with the ampoule. After the effect of detachment was observed due to the reduced force of gravity during the early experiments under microgravity conditions, in the past few years the Bridgman process likewise has been successfully used to grow at least partially detached under 1g-condition. If the requirements for detaching the melt meniscus from the ampoule wall are not fulfilled by the material-specific parameters (like e.g. wetting behavior between ampoule and melt and the growth angle of the crystal), detachment can be obtained also by the imposition of suitable pressure ratios in the growth ampoule. In the context of this paper, the growth of germanium by the detached and vertical Bridgman processes in pyrolytic boron nitride crucibles will be reported, Typical gap widths between ampoule wall and detached grown crystals are approximately 10-50 microns. Compared to the crystals grown with wall contact, a reduction of the etch pit density of approximately two orders of magnitude could be obtained by growing with the detached process.

  11. Monte Carlo simulation of electron detachment properties for {{\\text{O}_{2}^{{}}}^{-}} ions in oxygen and oxygen:nitrogen mixtures

    NASA Astrophysics Data System (ADS)

    Ponomarev, A. A.; Aleksandrov, N. L.

    2015-06-01

    Electron detachment properties of {{\\text{O}2{}}-} ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10-17 V·cm2). Swarm parameters were calculated for unexcited and vibrationally excited \\text{O}{{{}2}-} ions taking into account vibrational transfer and relaxation, charge transfer and electron detachment. The cross sections for vibrational transfer and relaxation in collisions between {{\\text{O}2{}}-} ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on electron detachment. Good agreement between the calculated detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on electron detachment.

  12. Numerical experiment to estimate the validity of negative ion diagnostic using photo-detachment combined with Langmuir probing

    SciTech Connect

    Oudini, N.; Sirse, N.; Ellingboe, A. R.; Benallal, R.; Taccogna, F.; Bendib, A.

    2015-07-15

    This paper presents a critical assessment of the theory of photo-detachment diagnostic method used to probe the negative ion density and electronegativity α = n{sub -}/n{sub e}. In this method, a laser pulse is used to photo-detach all negative ions located within the electropositive channel (laser spot region). The negative ion density is estimated based on the assumption that the increase of the current collected by an electrostatic probe biased positively to the plasma is a result of only the creation of photo-detached electrons. In parallel, the background electron density and temperature are considered as constants during this diagnostics. While the numerical experiments performed here show that the background electron density and temperature increase due to the formation of an electrostatic potential barrier around the electropositive channel. The time scale of potential barrier rise is about 2 ns, which is comparable to the time required to completely photo-detach the negative ions in the electropositive channel (∼3 ns). We find that neglecting the effect of the potential barrier on the background plasma leads to an erroneous determination of the negative ion density. Moreover, the background electron velocity distribution function within the electropositive channel is not Maxwellian. This is due to the acceleration of these electrons through the electrostatic potential barrier. In this work, the validity of the photo-detachment diagnostic assumptions is questioned and our results illustrate the weakness of these assumptions.

  13. Electric-field-induced electron detachment of 800-MeV H{sup {minus}} ions

    SciTech Connect

    Keating, P.B.; Gulley, M.S.; Bryant, H.C.; MacKerrow, E.P.; Miller, W.A.; Rislove, D.C.; Cohen, S.; Donahue, J.B.; Fitzgerald, D.H.; Funk, D.J.; Frankle, S.C.; Hutson, R.L.; Macek, R.J.; Plum, M.A.; Stanciu, N.G.; van Dyck, O.B.; Wilkinson, C.A.

    1995-12-01

    The lifetime of 800-MeV H{sup {minus}} ions against electron detachment in a static electric field was measured over a range of eight orders of magnitude in experiments at the High Resolution Atomic Beam Facility of the Los Alamos Meson Physics Facility. The ions traversed a linear gradient magnetic field of 1.3-T peak strength resulting in a 6-MV/cm peak rest-frame electric field capable of stripping a large fraction of H{sup {minus}} ions. The unstripped H{sup {minus}} ions, neutral H{sup 0} atoms, and protons were detected 5.5 m from the magnet. This spectrum was analyzed to determine the lifetime of the H{sup {minus}} ion versus electric-field strength and the results were compared with previous studies. Three parametrizations of the lifetime formula based on an existing theory were used to calculate the stripping probability. The data were fit to the lifetime formula and good agreement with theoretical predictions was found. Finally, a possible experiment for observing excited states of H{sup {minus}} is briefly discussed.

  14. Characterization of oligodeoxynucleotides by electron detachment dissociation fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Yang, Jiong; Mo, Jingjie; Adamson, Julie T; Håkansson, Kristina

    2005-03-15

    Electron detachment dissociation (EDD), recently introduced by Zubarev and co-workers for the dissociation of multiply charged biomolecular anions via a radical ion intermediate, has been shown to be analogous to electron capture dissociation (ECD) in several respects, including more random peptide fragmentation and retention of labile posttranslational modifications. We have previously demonstrated unique fragmentation behavior in ECD compared to vibrational excitation for oligodeoxynucleotide cations. However, that approach is limited by the poor sensitivity for oligonucleotide ionization in positive ion mode. Here, we show implementation of EDD on a commercial Fourier transform ion cyclotron resonance mass spectrometer utilizing two different configurations: a heated filament electron source and an indirectly heated hollow dispenser cathode electron source. The dispenser cathode configuration provides higher EDD efficiency and additional fragmentation channels for hexamer oligodeoxynucleotides. As in ECD, even-electron d/w ion series dominate the spectra, but we also detect numerous a/z (both even-electron and radical species), (a/z - B), c/x, (c/x - B), and (d/w - B) ions with minimal nucleobase loss from the precursor ions. In contrast to previous high-energy collision-activated dissociation (CAD) and ion trap CAD of radical oligonucleotide anions, we only observe minimum sugar cross-ring cleavage, possibly due to the short time scale of EDD, which limits secondary fragmentation. Thus, EDD provides fragmentation similar to ECD for oligodeoxynucleotides but at enhanced sensitivity. Finally, we show that noncovalent bonding in a DNA duplex can be preserved following EDD, illustrating another analogy with ECD. We believe the latter finding implies EDD has promise for characterization of nucleic acid structure and folding. PMID:15762599

  15. Listeria monocytogenes Attachment to and Detachment from Stainless Steel Surfaces in a Simulated Dairy Processing Environment▿

    PubMed Central

    Poimenidou, Sofia; Belessi, Charalambia A.; Giaouris, Efstathios D.; Gounadaki, Antonia S.; Nychas, George-John E.; Skandamis, Panagiotis N.

    2009-01-01

    The presence of pathogens in dairy products is often associated with contamination via bacteria attached to food-processing equipment, especially from areas where cleaning/sanitation is difficult. In this study, the attachment of Listeria monocytogenes on stainless steel (SS), followed by detachment and growth in foods, was evaluated under conditions simulating a dairy processing environment. Initially, SS coupons were immersed in milk, vanilla custard, and yogurt inoculated with the pathogen (107 CFU/ml or CFU/g) and incubated at two temperatures (5 and 20°C) for 7 days. By the end of incubation, cells were mechanically detached from coupons and used to inoculate freshly pasteurized milk which was subsequently stored at 5°C for 20 days. The suspended cells in all three products in which SS coupons were immersed were also used to inoculate freshly pasteurized milk (5°C for 20 days). When SS coupons were immersed in milk, shorter lag phases were obtained for detached than for planktonically grown cells, regardless of the preincubation temperature (5 or 20°C). The opposite was observed when custard incubated at 20°C was used to prepare the two types of inocula. However, in this case, a significant increase in growth rate was also evident when the inoculum was derived from detached cells. In another parallel study, while L. monocytogenes was not detectable on SS coupons after 7 days of incubation (at 5°C) in inoculated yogurt, marked detachment and growth were observed when these coupons were subsequently transferred and incubated at 5°C in fresh milk or/and custard. Overall, the results obtained extend our knowledge on the risk related to contamination of dairy products with detached L. monocytogenes cells. PMID:19767476

  16. Role of pulsed winds on detachment of low salinity water from the Pearl River Plume: Upwelling and mixing processes

    NASA Astrophysics Data System (ADS)

    Chen, Zhaoyun; Pan, Jiayi; Jiang, Yuwu

    2016-04-01

    The detachment of low salinity water (LSW) from the Pearl River plume occurs frequently as revealed by in situ observations and satellite images, and plays an important role in cross-shore transport of the nutrient-rich plume water. In this study, the Regional Ocean Modeling System (ROMS) is used to simulate the LSW detachment process forced by realistic and idealized winds, and to explore its dynamical mechanisms. Modeling results show that the LSW detachment appears under a pulsed southwesterly wind, while tidal mixing modifies the size and salinity of the detached LSW. Strong pulsed wind causes the LSW to separate from the plume and move offshore quickly after the detachment. Under a pulsed northeasterly wind, however, the plume without separation of the LSW moves shoreward, indicating that the LSW detachment is sensitive to wind direction. In the plume region, upwelling develops under the forcing of the pulsed southwesterly wind, which transports high salinity bottom water to the surface layer, while the shear mixing in the upper layer further enhances the surface buoyancy flux, leading to appearance of high salinity water in the surface layer off the Pearl River estuary mouth, cutting off the eastward-spreading plume water, and resulting in the plume LSW detachment. Further analysis shows that the pulsed southwesterly wind induces positive local salinity change rate in the LSW detachment area. The pulsed upwelling-favorable wind with duration of 2-5 days is responsible for the detachment process.

  17. Salix polaris growth responses to active layer detachment and solifluction processes in High Arctic.

    NASA Astrophysics Data System (ADS)

    Siekacz, Liliana

    2015-04-01

    The work is dedicated to demonstrate the potential of Salix polaris grow properties in the dendrogemorphologic image, analyzing periglacially induced slope processes in the high Arctic.. Observed anatomical and morphological plants responses to solifluction and active layer detachment processes are presented qualitatively and quantitatively as a summary of presented features frequency. The results are discussed against the background of the other research results in this field. The investigations was performed in Ebba valley, in the vicinity of Petunia Bay, northernmost part of Billefjorden in central Spitsbergen (Svalbard). Environmental conditions are characterized by annual precipitation sum lower than 200 mm (Hagen et al.,1993) and average summer temperature of about 5°C, with maximum daily temperatures rarely exceeding 10°C (Rachlewicz, 2009). Collected shrub material was prepared according to the methods presented by Schweingruber and Poschlod (2005). Thin (approx. 15-20μm) sections of the whole cross-section were prepared with a sledge microtome, stained with Safranine and Astra blue and finally permanently fixed on microslides with Canada balsam and dried. Snapshots were taken partially for each cross-section with digital camera (ColorView III, Olympus) connected to a microscope (Olympus BX41) and merged into one, high resolution image. After all, ring widths were measured in 3-4 radii in every single cross-section using ImageJ software. Analyzed plants revealed extremely harsh environmental conditions of their growth. Buchwał et al. (2013) provided quantitative data concerning missing rings and partially missing rings in shrubs growing on Ebba valley floor. Mean ring width at the level of 79μm represents one of the smallest values of yearly growth ever noted. The share of missing rings and partially missing rings was 11,2% and 13,6% respectively. Plants growing on Ebba valley slope indicate almost twice smaller values of ring width (41μm), and higher

  18. Growth Rate of Calcite Steps as a Function of Aqueous Calcium-to-Carbonate Ratio: Independent Attachment and Detachment of Calcium and Carbonate Ions

    SciTech Connect

    Stack, Andrew G; Grantham, Ms. Meg

    2010-01-01

    Growth rates of monolayer-height steps on the {1014} calcite surface have been measured as a function of the aqueous calcium-to-carbonate ratio. The maximum growth rates of the two common crystallographic orientations were found to deviate from the ideal stoichiometric ratio of 1:1, and dissolution features were observed under supersaturated solutions containing high calcium-to-carbonate ratios. To explain these phenomena, a theory is applied that treats the rates of attachment and detachment of aqueous calcium and carbonate ions separately. The resultant attachment rate constants are 1-3 orders of magnitude smaller than the water exchange rate of the constituent aqueous ions, suggesting that ligand-exchange processes may directly drive attachment. The broader implication is that the saturation state alone is not adequate to fully describe the rates of the multiple, independent reactions that occur on mineral surfaces under these conditions.

  19. Shape Change of the Vitreous Chamber Influences Retinal Detachment and Reattachment Processes: Is Mechanical Stress during Eye Rotations a Factor?

    PubMed Central

    Meskauskas, Julia; Repetto, Rodolfo; Siggers, Jennifer H.

    2012-01-01

    Purpose. We aim to understand how mechanical causation influences retinal detachment and reattachment processes. In particular, myopes suffer retinal detachment more frequently than emmetropes, and following a retinal detachment, scleral buckling promotes retinal reattachment. We test the hypothesis that stresses arising from saccadic eye rotations are involved in the processes, and that the alteration in the stress due to the change in the vitreous chamber geometry is sufficient to explain the phenomena. Methods. The vitreous chamber of the eye has an approximately spherical shape and it is filled with vitreous humor. We developed a mathematical model, treating the vitreous chamber in emmetropic and myopic eyes as a spheroid and in eyes subjected to scleral buckling as a sphere with a circumferential indentation. We assume that the eye performs prescribed small-amplitude, periodic, torsional rotations and we solve semi-analytically for the fluid pressure, velocity, and stress distributions. Results. The shape of the vitreous chamber has a large effect on the retinal stress. The vitreous and the retina of a highly myopic eye continuously experience shear stresses significantly higher than those of an emmetropic eye. An eye fitted with a scleral buckle experiences large stress levels localized around the buckle. Conclusions. Our results provide a mechanical explanation for the more frequent occurrence of posterior vitreous detachment and retinal detachment in myopic eyes. To understand how the stress distribution in a buckled eye facilitates reattachment, an additional model of the details of the reattachment process should be coupled to this model. PMID:22899755

  20. High-Field Asymmetric-Waveform Ion Mobility Spectrometry and Electron Detachment Dissociation of Isobaric Mixtures of Glycosaminoglycans

    NASA Astrophysics Data System (ADS)

    Kailemia, Muchena J.; Park, Melvin; Kaplan, Desmond A.; Venot, Andre; Boons, Geert-Jan; Li, Lingyun; Linhardt, Robert J.; Amster, I. Jonathan

    2013-11-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is shown to be capable of resolving isomeric and isobaric glycosaminoglycan negative ions and to have great utility for the analysis of this class of molecules when combined with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tandem mass spectrometry. Electron detachment dissociation (EDD) and other ion activation methods for tandem mass spectrometry can be used to determine the sites of labile sulfate modifications and for assigning the stereochemistry of hexuronic acid residues of glycosaminoglycans (GAGs). However, mixtures with overlapping mass-to-charge values present a challenge, as their precursor species cannot be resolved by a mass analyzer prior to ion activation. FAIMS is shown to resolve two types of mass-to-charge overlaps. A mixture of chondroitin sulfate A (CSA) oligomers with 4-10 saccharides units produces ions of a single mass-to-charge by electrospray ionization, as the charge state increases in direct proportion to the degree of polymerization for these sulfated carbohydrates. FAIMS is shown to resolve the overlapping charge. A more challenging type of mass-to-charge overlap occurs for mixtures of diastereomers. FAIMS is shown to separate two sets of epimeric GAG tetramers. For the epimer pairs, the complexity of the separation is reduced when the reducing end is alkylated, suggesting that anomers are also resolved by FAIMS. The resolved components were activated by EDD and the fragment ions were analyzed by FTICR-MS. The resulting tandem mass spectra were able to distinguish the two epimers from each other.

  1. Retinal Detachment: Torn or Detached Retina Diagnosis

    MedlinePlus

    ... Eye Health / Eye Health A-Z Detached or Torn Retina Sections Retinal Detachment: What Is a Torn ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment: Torn or Detached Retina Diagnosis Written by: Kierstan Boyd ...

  2. Retinal Detachment: Torn or Detached Retina Symptoms

    MedlinePlus

    ... Eye Health / Eye Health A-Z Detached or Torn Retina Sections Retinal Detachment: What Is a Torn ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment: Torn or Detached Retina Symptoms Written by: Kierstan Boyd ...

  3. Rock fall susceptibility assessment using structural geological indicators for detaching processes such as sliding or toppling

    NASA Astrophysics Data System (ADS)

    Melzner, Sandra; Tilch, Nils; Lotter, Michael; Kociu, Arben

    2010-05-01

    A structural geological assessment of cliffs in terms of rock fall susceptibility is expensive and time-consuming particularly in remote areas (exposed cliffs) where it may even be impossible. Hence it is important to develop methods and strategies that can be used to extrapolate the acquired knowledge from representative sub-regions to the whole study area. Using a case study in Carinthia (Austria), a GIS method was developed which can be used for regional, qualitative determination of the susceptibility of cliffs in carbonatic sedimentary rock, regarding two potential initial detachment processes of rock fall: sliding and/or toppling. During the development of this GIS method, it was found that not all of the mapped structural geologic parameters are equally suitable for a comprehensive regionalisation. Subsequently, only those parameters were included in the assessment which experts deemed to be representative in terms of parameter homogeneity/heterogeneity and thus applicable to the entire survey region: bedding thickness, tectonic lineaments, orientation of discontinuities and type of rock mass structure. Regions of homogeneity/heterogeneity differ with regard to parameter values, as well as parameter uncertainties and scattering. At first, the cliffs were categorised in terms of potential form and size of rock blocks by overlaying various parameter maps. In the next step, the relative orientation of the rock mass structures and their variations towards slope aspect and slope inclination were considered within a region of homogeneity. This allowed an accurate estimate of the possible maximum dip angle (or apparent dip angle) of a joint set over a wide area. It also permitted those areas to be pointed out in which process-initialising sliding and/or toppling might be possible along one or several joint sets. Comparing this method to the acquired field data has proven the approach to be successful when it comes to assessing cliffs in carbonate rocks in terms of

  4. Retinal detachment

    MedlinePlus

    ... separate from the underlying tissues, much like a bubble under wallpaper. This is most often caused by ... small detachment, the doctor may place a gas bubble in the eye. This is called pneumatic retinopexy. ...

  5. Retinal Detachment

    MedlinePlus

    ... immediately. Treatment How is retinal detachment treated? Small holes and tears are treated with laser surgery or ... laser surgery tiny burns are made around the hole to “weld” the retina back into place. Cryopexy ...

  6. The social organization of surrogacy: relinquishing a baby and the role of payment in the psychological detachment process.

    PubMed

    Baslington, Hazel

    2002-01-01

    This article presents the 'maternal-foetal detachment' theory providing a framework for understanding how some women relinquish a baby in the context of paid surrogacy. It is postulated that attitude towards payment becomes part of a psychological detachment process in which surrogate mothers emotionally distance themselves from the growing foetus. Important are the subcultural influences engendered by the social organization of surrogacy. Some surrogate mothers appear to learn not to attach to the unborn child or, if feelings emerge, they deal with these by deflecting emotions towards the couple. The discussion considers what can be learned about the concepts of maternal-foetal attachment and maternal instinct. The surrogacy case offers conflicting evidence in favour of, and in opposition to, the concept of maternal instinct. PMID:22114227

  7. Theoretical investigation of electron transfer and detachment processes in low energy H- + Li and Li- + H collisions

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Lin, X. H.; Yan, B.; Wang, J. G.; Janev, R. K.

    2016-02-01

    The charge exchange and collisional detachment processes in H- + Li and Li- + H collisions have been studied by using the quantal molecular orbital close-coupling (QMOCC) method in the energy ranges of about 0.12-1000 eV u-1 and 0.1 meV-1000 eV, respectively, and the inelastic collision cross sections and rate coefficients have been computed and presented. It is found that the electron transfer process in the H- + Li and Li- + H collisions is due to the Demkov coupling between the 12Σ+ and 22Σ+ states at internuclear distances of about 15a0. The collisional electron detachment in the considered collision system is due to the excitation of the remaining six states, which are all unstable against autodetachment. These states are populated through a series of Landau-Zener couplings of the 22Σ+ state with upper 2Σ+ states and by the rotational 2Σ+-2Π couplings at small internuclear distances. The cross sections for electron transfer in H- + Li and Li- + H collisions in the energy range of 10-1000 eV u-1 attain values in the range of 10-16-10-15 cm2 (reaching their maximum values of about 5 × 10-15 cm2 at 500-600 eV u-1), while the values of the corresponding electron detachment cross sections in this energy range attain generally smaller values.

  8. Bacteriophage PRD1 batch experiments to study attachment, detachment and inactivation processes

    NASA Astrophysics Data System (ADS)

    Sadeghi, Gholamreza; Schijven, Jack F.; Behrends, Thilo; Hassanizadeh, S. Majid; van Genuchten, Martinus Th.

    2013-09-01

    Knowledge of virus removal in subsurface environments is pivotal for assessing the risk of viral contamination of water resources and developing appropriate protection measures. Columns packed with sand are frequently used to quantify attachment, detachment and inactivation rates of viruses. Since column transport experiments are very laborious, a common alternative is to perform batch experiments where usually one or two measurements are done assuming equilibrium is reached. It is also possible to perform kinetic batch experiments. In that case, however, it is necessary to monitor changes in the concentration with time. This means that kinetic batch experiments will be almost as laborious as column experiments. Moreover, attachment and detachment rate coefficients derived from batch experiments may differ from those determined using column experiments. The aim of this study was to determine the utility of kinetic batch experiments and investigate the effects of different designs of the batch experiments on estimated attachment, detachment and inactivation rate coefficients. The experiments involved various combinations of container size, sand-water ratio, and mixing method (i.e., rolling or tumbling by pivoting the tubes around their horizontal or vertical axes, respectively). Batch experiments were conducted with clean quartz sand, water at pH 7 and ionic strength of 20 mM, and using the bacteriophage PRD1 as a model virus. Values of attachment, detachment and inactivation rate coefficients were found by fitting an analytical solution of the kinetic model equations to the data. Attachment rate coefficients were found to be systematically higher under tumbling than under rolling conditions because of better mixing and more efficient contact of phages with the surfaces of the sand grains. In both mixing methods, more sand in the container yielded higher attachment rate coefficients. A linear increase in the detachment rate coefficient was observed with increased

  9. Retinal detachment

    MedlinePlus

    ... of the first symptoms of new flashes of light and floaters. ... diabetes. See your eye care specialist once a year. You may need more frequent visits if you have risk factors for retinal detachment. Be alert to symptoms of new flashes of light and floaters.

  10. Impurity ion flow and temperature measured in a detached divertor with externally applied non-axisymmetric fields on DIII-D

    DOE PAGESBeta

    Briesemeister, A. R.; Isler, R. C.; Allen, S. L.; Ahn, J. -W.; McLean, A. G.; Unterberg, E. A.; Hillis, D. L.; Fenstermacher, M. E.; Meyer, W. H.

    2014-11-15

    Externally applied non-axisymmetric magnetic fields are shown to have little effect on the impurity ion flow velocity and temperature as measured by the multichord divertor spectrometer in the DIII-D divertor for both attached and detached conditions. These experiments were performed in H-mode plasmas with the grad-B drift toward the target plates, with and without n = 3 resonant magnetic perturbations (RMPs). The flow velocity in the divertor is shown to change by as much as 30% when deuterium gas puffing is used to create detachment of the divertor plasma. No measurable changes in the C III flow were observed inmore » response to the RMP fields for the conditions used in this work. Images of the C III emission are used along with divertor Thomson scattering to show that the local electron and C III temperatures are equilibrated for the conditions shown.« less

  11. Impurity ion flow and temperature measured in a detached divertor with externally applied non-axisymmetric fields on DIII-D

    NASA Astrophysics Data System (ADS)

    Briesemeister, A. R.; Isler, R. C.; Allen, S. L.; Ahn, J.-W.; McLean, A. G.; Unterberg, E. A.; Hillis, D. L.; Fenstermacher, M. E.; Meyer, W. H.

    2015-08-01

    Externally applied non-axisymmetric magnetic fields are shown to have little effect on the impurity ion flow velocity and temperature as measured by the multichord divertor spectrometer in the DIII-D divertor for both attached and detached conditions. These experiments were performed in H-mode plasmas with the grad-B drift toward the target plates, with and without n = 3 resonant magnetic perturbations (RMPs). The flow velocity in the divertor is shown to change by as much as 30% when deuterium gas puffing is used to create detachment of the divertor plasma. No measurable changes in the C III flow were observed in response to the RMP fields for the conditions used in this work. Images of the C III emission are used along with divertor Thomson scattering to show that the local electron and C III temperatures are equilibrated for the conditions shown.

  12. Ion funnel ion trap and process

    DOEpatents

    Belov, Mikhail E [Richland, WA; Ibrahim, Yehia M [Richland, WA; Clowers, Biran H [West Richland, WA; Prior, David C [Hermiston, OR; Smith, Richard D [Richland, WA

    2011-02-15

    An ion funnel trap is described that includes a inlet portion, a trapping portion, and a outlet portion that couples, in normal operation, with an ion funnel. The ion trap operates efficiently at a pressure of .about.1 Torr and provides for: 1) removal of low mass-to-charge (m/z) ion species, 2) ion accumulation efficiency of up to 80%, 3) charge capacity of .about.10,000,000 elementary charges, 4) ion ejection time of 40 to 200 .mu.s, and 5) optimized variable ion accumulation times. Ion accumulation with low concentration peptide mixtures has shown an increase in analyte signal-to-noise ratios (SNR) of a factor of 30, and a greater than 10-fold improvement in SNR for multiply charged analytes.

  13. Detachment of Tertiary Dendrite Arms during Controlled Directional Solidification in Aluminum - 7 wt Percent Silicon Alloys: Observations from Ground-based and Microgravity Processed Samples

    NASA Technical Reports Server (NTRS)

    Grugel, Richard N.; Erdman, Robert; Van Hoose, James R.; Tewari, Surendra; Poirier, David

    2012-01-01

    Electron Back Scattered Diffraction results from cross-sections of directionally solidified aluminum 7wt% silicon alloys unexpectedly revealed tertiary dendrite arms that were detached and mis-oriented from their parent arm. More surprisingly, the same phenomenon was observed in a sample similarly processed in the quiescent microgravity environment aboard the International Space Station (ISS) in support of the joint US-European MICAST investigation. The work presented here includes a brief introduction to MICAST and the directional solidification facilities, and their capabilities, available aboard the ISS. Results from the ground-based and microgravity processed samples are compared and possible mechanisms for the observed tertiary arm detachment are suggested.

  14. Retinal Detachment Vision Simulator

    MedlinePlus

    ... Retina Treatment Retinal Detachment Vision Simulator Retinal Detachment Vision Simulator Mar. 01, 2016 How does a detached or torn retina affect your vision? If a retinal tear is occurring, you may ...

  15. Investigation of detachment and transport processes of sediment using different sand mixtures in high precision rainfall simulations

    NASA Astrophysics Data System (ADS)

    Fister, Wolfgang; Mayer, Marius; Reichle, Elisabeth; Kinnell, Peter I. A.; Kuhn, Nikolaus J.

    2016-04-01

    Detachment and transport of sediment in the landscape are controlled by many different factors. Beside environmental factors such as soil surface properties, land management and vegetation cover, the dominant ones are rainfall and surface flow characteristics. In order to be able to investigate the change of sediment properties over transport distance and time, it is, therefore, necessary to understand the basic interactions between rainfall kinetic energy and amount, particle size and density as well as flow depth and velocity. So far, the mechanistic understanding of these principal physical interactions is mostly of empirical nature, obtained either under natural, highly complex and uncontrollable conditions, or with rainfall experiments that weren't able to control the conditions with high enough precision. The aim of this study was, therefore, to fill this gap of knowledge in our mechanical process understanding by conducting rainfall experiments on different sand mixtures. In this bottom-up approach, the highly controlled experimental conditions and the use of stable sand ensured that the number of variable factors was kept to a minimum. Thus, specific relations between sand-sizes, drop kinetic energy, force of flow, and resulting erosion rates could be obtained. Although the results are very promising and could lead to a better understanding of the erosion processes in the future, they clearly show that already straightforward sand mixtures behave in a very complex way. Further experiments with simple grain mixtures are, therefore, needed before experiments on more complex, instable sediments can or should be investigated.

  16. Experimental Characterization of Plasma Detachment from Magnetic Nozzles

    NASA Astrophysics Data System (ADS)

    Olsen, Christopher Scott

    Magnetic nozzles, like Laval nozzles, are observed in several natural systems and have application in areas such as electric propulsion and plasma processing. Plasma flowing through these nozzles is inherently tied to the field lines and must separate for momentum redirection or particle transport to occur. Plasma detachment and associated mechanisms from a magnetic nozzle are investigated. Experimental results are presented from the plume of the VASIMRRTM VX-200 device flowing along an axisymmetric magnetic nozzle and operated at two ion energies to explore momentum dependent detachment. The argon plume expanded into a 150m3 vacuum chamber where the background pressure was low enough that charge-exchange mean-free-paths were longer than experiment scale lengths. This magnetic nozzle system is demonstrated to hydrodynamically scale up to astrophysical plasmas, particularly the solar chromosphere, implying general relevance to many systems. Plasma parameters were mapped over a large spatial range using measurements from multiple plasma diagnostics. The data show that the plume does not follow the magnetic field lines. A mapped integration of the ion flux shows the plume may be divided into three regions where 1) the plume briefly follows the magnetic flux, 2) diverges quadratically before 3) expanding with linear trajectories. Transitioning from region 1→2, the ion flux departs from the magnetic flux suggesting ion detachment. An instability forms in region 2 driving an oscillating electric field that causes ions to expand before enhancing electron cross-field transport through anomalous resistivity. Transitioning from region 2→3 the electric field dissipates, the trajectories linearize, and the plume effectively detaches. A delineation of sub-to-super Alfvenic flow aligns well with the inflection points of the linearization without a change in magnetic topology. The detachment process is best described as a two part process: First, ions detach by a breakdown of

  17. Orthogonal ion injection apparatus and process

    DOEpatents

    Kurulugama, Ruwan T; Belov, Mikhail E

    2014-04-15

    An orthogonal ion injection apparatus and process are described in which ions are directly injected into an ion guide orthogonal to the ion guide axis through an inlet opening located on a side of the ion guide. The end of the heated capillary is placed inside the ion guide such that the ions are directly injected into DC and RF fields inside the ion guide, which efficiently confines ions inside the ion guide. Liquid droplets created by the ionization source that are carried through the capillary into the ion guide are removed from the ion guide by a strong directional gas flow through an inlet opening on the opposite side of the ion guide. Strong DC and RF fields divert ions into the ion guide. In-guide orthogonal injection yields a noise level that is a factor of 1.5 to 2 lower than conventional inline injection known in the art. Signal intensities for low m/z ions are greater compared to convention inline injection under the same processing conditions.

  18. Process in high energy heavy ion acceleration

    NASA Astrophysics Data System (ADS)

    Dinev, D.

    2009-03-01

    A review of processes that occur in high energy heavy ion acceleration by synchrotrons and colliders and that are essential for the accelerator performance is presented. Interactions of ions with the residual gas molecules/atoms and with stripping foils that deliberately intercept the ion trajectories are described in details. These interactions limit both the beam intensity and the beam quality. The processes of electron loss and capture lie at the root of heavy ion charge exchange injection. The review pays special attention to the ion induced vacuum pressure instability which is one of the main factors limiting the beam intensity. The intrabeam scattering phenomena which restricts the average luminosity of ion colliders is discussed. Some processes in nuclear interactions of ultra-relativistic heavy ions that could be dangerous for the performance of ion colliders are represented in the last chapter.

  19. Ion loss processes in the stratosphere

    NASA Technical Reports Server (NTRS)

    Prasad, B. S. N.; Chandramma, S.

    1985-01-01

    Small ions consisting of aggregates of a few molecules determine th stratospheric electrical parameters such as conductivity, mobility, etc. The small ion density is controlled by the ionizing mechanisms for the production of ions and electrons and the loss processes for these charged particles. Ion production in stratosphere is chiefly due to galactic cosmic rays, and the loss processes due to recombination and attachment. Free electrons do not exist at stratospheric heights. The primary positive ion O2+ and the electrons are converted into complex clusters of positive and negative ions. The equilibrium ion density is governed by the equation of continuity for the production and loss of these ions. In the generalized equation of continuity, the gain or loss of ions due to transport is neglected. When aerosols or particulates are not present in the atmosphere, ions are loss due to ion-ion recombination. In the presence of aerosols, small ions can also be lost by attachment to the aerosols, and thus aerosols are likely to cause perturbations in the stratosphere electrification. A simplified model approach is adopted to study the effect of aerosols on the equilibrium ion density. The results of the analysis for the equatorial station Thumba (8.5 deg N) are presented.

  20. Stability of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.; Croell, A.

    2009-01-01

    Bridgman crystal growth can be conducted in the so-called "detached" solidification regime, where the growing crystal is detached from the crucible wall. A small gap between the growing crystal and the crucible wall, of the order of 100 micrometers or less, can be maintained during the process. A meniscus is formed at the bottom of the melt between the crystal and crucible wall. Under proper conditions, growth can proceed without collapsing the meniscus. The meniscus shape plays a key role in stabilizing the process. Thermal and other process parameters can also affect the geometrical steady-state stability conditions of solidification. The dynamic stability theory of the shaped crystal growth process has been developed by Tatarchenko. It consists of finding a simplified autonomous set of differential equations for the radius, height, and possibly other process parameters. The problem then reduces to analyzing a system of first order linear differential equations for stability. Here we apply a modified version of this theory for a particular case of detached solidification. Approximate analytical formulas as well as accurate numerical values for the capillary stability coefficients are presented. They display an unexpected singularity as a function of pressure differential. A novel approach to study the thermal field effects on the crystal shape stability has been proposed. In essence, it rectifies the unphysical assumption of the model that utilizes a perturbation of the crystal radius along the axis as being instantaneous. It consists of introducing time delay effects into the mathematical description and leads, in general, to stability over a broader parameter range. We believe that this novel treatment can be advantageously implemented in stability analyses of other crystal growth techniques such as Czochralski and float zone methods.

  1. Ion processing element with composite media

    DOEpatents

    Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

    2009-03-24

    An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

  2. Ion processing element with composite media

    DOEpatents

    Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

    2003-02-04

    An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

  3. Medical applications of ion beam processes

    NASA Astrophysics Data System (ADS)

    Sioshansi, P.

    The use of ions beams for treatment of surfaces in medical prostheses has gained increasing interest in the past few years. The application of ion beams has taken different forms: (1) ion implantation has been used for increasing the hardness and wear resistance of the new generation titanium based alloys, as well as reducing the wear of the mating polyethylene component used in orthopedic total joint replacement. Spire Corporation has been successful in commercializing ion implantation technology and is processing several thousand artificial knees and hips per year. (Spire uses the tradename IONGUARD™ for this application.) (2) Similarly, ion implantation has proven to be very effective for increasing the corrosion resistance of the Co-Cr based alloys that have traditionally been used in orthopedic prostheses. This application should be of particular interest in resolving the issues surrounding ion release problems associated with these alloys. (3) Ion beam etching/milling has been used for producing a highly textured surface for tissue ingrowth in applications ranging from porous orthopedic implants and percutaneous devices to artificial skin and the process should have a significant impact in this application. (4) There are indications that ion implantation is a useful process for increasing biocompatibility and tissue attachment on metallic samples. This subject deserves considerable attention in the coming years.

  4. Ion beam processing of advanced electronic materials

    SciTech Connect

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B.; International Business Machines Corp., Yorktown Heights, NY . Thomas J. Watson Research Center; Oak Ridge National Lab., TN )

    1989-01-01

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  5. Isotopic evidence (B, C, O) of deep fluid processes in fault rocks from the active Woodlark Basin detachment zone

    NASA Astrophysics Data System (ADS)

    Kopf, Achim; Behrmann, Jan H.; Deyhle, Annette; Roller, Sybille; Erlenkeuser, Helmut

    2003-03-01

    We report results from boron, carbon and oxygen stable isotope analyses of faulted and veined rocks recovered by scientific ocean drilling during ODP Leg 180 in the western Woodlark Basin, off Papua New Guinea. In this area of active continental extension, crustal break-up and incipient seafloor spreading, a shallow-dipping, seismically active detachment fault accommodates strain, defining a zone of mylonites and cataclasites, vein formation and fluid infiltration. Syntectonic microstructures and vein-fill mineralogy suggest frictional heating during slip during extension and exhumation of Moresby Seamount. Low carbon and oxygen isotope ratios of calcite veins indicate precipitation from hydrothermal fluids (δ 13C PDB down to -17‰; δ 18O PDB down to -22‰) formed by both dehydration and decarbonation. Boron contents are low (<7 ppm), indicating high-grade metamorphic source rock for the fluids. Some of the δ 11B signatures (17-35‰; parent solutions to calcite vein fills) are low when compared to deep-seated waters in other tectonic environments, likely reflecting preferential loss of 11B during low-grade metamorphism at depth. Pervasive devolatilization and flux of CO 2-rich fluids are evident from similar vein cement geochemistry in the detachment fault zone and splays further updip. Multiple rupture-and-healing history of the veins suggests that precipitation may be an important player in fluid pressure evolution and, hence, seismogenic fault movement.

  6. Descemet membrane detachment.

    PubMed

    Mackool, R J; Holtz, S J

    1977-03-01

    Four eyes of three patients had extensive postoperative Descemet membrane (DM) detachment. Blood was present just anterior to the DM in three of the four eyes and later converted to and persisted as pigment. Haziness of the cornea at the level of the DM could be seen with reattachment. Detachments of the DM are classified as planar when there is 1 mm or less separation of the DM from its overlying stroma in all areas. Nonplanar DM detachments exceed 1 mm of separation. Planar detachments have a much better prognosis than nonplanar detachments do, with or without descemetopexy. Repair of DM detachments, when necessary, should include air injection, with the lease possible instrumentation of the DM. PMID:843278

  7. Composite media for ion processing

    DOEpatents

    Mann, Nick R.; Wood, Donald J.; Todd, Terry A.; Sebesta, Ferdinand

    2009-12-08

    Composite media, systems, and devices for substantially removing, or otherwise processing, one or more constituents of a fluid stream. The composite media comprise a plurality of beads, each having a matrix substantially comprising polyacrylonitrile (PAN) and supporting one or more active components which are effective in removing, by various mechanisms, one or more constituents from a fluid stream. Due to the porosity and large surface area of the beads, a high level of contact is achieved between composite media of the present invention and the fluid stream being processed. Further, the homogeneity of the beads facilitates use of the beads in high volume applications where it is desired to effectively process a large volume of flow per unit of time.

  8. Quantum information processing with trapped ion chains

    NASA Astrophysics Data System (ADS)

    Manning, Timothy Andrew

    Trapped atomic ion systems are currently the most advanced platform for quantum information processing. Their long coherence times, pristine state initialization and detection, and precisely controllable and versatile interactions make them excellent quantum systems for experiments in quantum computation and quantum simulation. One of the more promising schemes for quantum computing consists of performing single and multi-qubit quantum gates on qubits in a linear ion crystal. Some of the key challenges of scaling such a system are the individual addressing of arbitrary subsets of ions and controlling the growing complexity of motional mode interactions as the number of qubits increases or when the gates are performed faster. Traditional entangling quantum gates between ion qubits use laser pulses to couple the qubit states to the collective motion of the crystal, thereby generating a spin-spin interaction that can produce entanglement between selected qubits. The intrinsic limitations on the performance of gates using this method can be alleviated by applying optimally shaped pulses instead of pulses with constant amplitude. This thesis explains the theory behind this pulse shaping scheme and how it is implemented on a chain of Yb ions held in a linear radiofrequency 'Paul' trap. Several experiments demonstrate the technique in chains of two, three, and five ions using various types of pulse shapes. A tightly focused individual addressing beam allows us to apply the entangling gates to a target pair of ions, and technical issues related to such tight focusing are discussed. Other advantages to the pulse shaping scheme include a robustness against detuning errors and the possibility of suppressing undesirable coupling due to optical spillover on neighboring ions. Combined with ion shuttling, we harness these features to perform sequential gates to different qubit pairs in order to create genuine tripartite entangled states and demonstrate the programmable quantum

  9. A New Interpretation of the CrO-Photoelectron Detachment Experiment

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Gutsev, G. L.; Arnold, Jim (Technical Monitor)

    2001-01-01

    CASSCF/MRCI calculations are performed on CrO(-) and CrO. The ground state of CrO(-) is identified as 4-II, not 6-Epsilon(+), as recently suggested. We assign the experimental detachment features to the seven one-electron processes arising from the two ion states.

  10. Modeling of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Popov, Dmitri

    1997-01-01

    Our long term goal is to develop techniques to achieve detached solidification reliably and reproducibly, in order to produce crystals with fewer defects. To achieve this goal it is necessary to understand thoroughly the physics of detached solidification. It was the primary objective of the current project to make progress toward this complete understanding. 'Me products of this grant are attached. These include 4 papers and a preliminary survey of the observations of detached solidification in space. We have successfully modeled steady state detached solidification, examined the stability of detachment, and determined the influence of buoyancy-driven convection under different conditions. Directional solidification in microgravity has often led to ingots that grew with little or no contact with the ampoule wall. When this occurred, crystallographic perfection was usually greatly improved -- often by several orders of magnitude. Indeed, under the Soviet microgravity program the major objective was to achieve detached solidification with its resulting improvement in perfection and properties. Unfortunately, until recently the true mechanisms underlying detached solidification were unknown. As a consequence, flight experiments yielded erratic results. Within the past three years, we have developed a new theoretical model that explains many of the flight results. This model gives rise to predictions of the conditions required to yield detached solidification.

  11. Surface modification by plasma immersion ion processing

    NASA Astrophysics Data System (ADS)

    Walter, Kevin C.; Lee, Deok H.; He, X. M.; Baker, N. P.; Nastasi, Michael; Munson, C. P.; Scarborough, W. K.; Tuszewski, M.; Wood, B. P.

    1998-09-01

    Los Alamos National Laboratory is actively researching a surface modification technique called plasma immersion ion processing (PIIP). PIIP is the latest innovation of the plasma source ion implantation (PSII) approach to surface modification. Like PSII, PIIP allows the modification of large areas and non-planar surface geometries, however PIIP is primarily a coating deposition technology rather than solely an ion implantation technology. PIIP utilizes a pulsed-bias on a target to extract ions out of plasma for ion implantation and coating deposition. Plasmas can be made by capacitive or inductive radio frequency sources or by initiating a glow discharge during each pulse of high voltage. Plasmas of hydrocarbon gases have been used to deposit adherent diamond-like carbon (DLC) coating son a variety of ferrous and non-ferrous materials. Instead of sputter depositing interlayers to improve the adhesion of DLC, PIIP uses ion implantation to create a graded interface between the metallic substrate and the DLC coating. Demonstrating the scaleability of PIIP, a 3 m2 area has been simultaneously coated with an adherent DLC coating approximately 7 micrometers thick. Plasmas of diborane and acetylene mixtures are being used to develop deposition processes for boron-carbide coatings. Through the use of organometallics and inorganic gases, other coatings are possible. The PIIP deposition conditions, composition and tribological properties of DLC and boron-carbide coatings will be highlighted.

  12. Electromagnetic processes in relativistic heavy ion collisions

    NASA Astrophysics Data System (ADS)

    Bertulani, C. A.; Baur, G.

    1986-10-01

    Electromagnetic effects in relativistic heavy ion collisions with impact parameter larger than the sum of the nuclear radii are studied using the virtual photon method. With increasing value of the relativistic parameter γ the hardness of the virtual photon spectrum increases. This leads to interesting new effects which will also have to be considered in the design of future relativistic heavy ion machines and experiments. The excitation of high-lying giant E1 and E2 multipole resonances is calculated as well as electromagnetic pion production. Coulomb bremsstrahlung is calculated and compared to the bremsstrahlung emitted in the more violent central nuclear collisions. K-shell ionization and electron-positron pair production is studied. The latter process has a very large cross section for heavy ions and contributes significantly to the stopping power of relativistic heavy ions in a dense medium.

  13. On plasma detachment in propulsive magnetic nozzles

    SciTech Connect

    Ahedo, Eduardo; Merino, Mario

    2011-05-15

    Three detachment mechanisms proposed in the literature (via resistivity, via electron inertia, and via induced magnetic field) are analyzed with an axisymmetric model of the expansion of a small-beta, weakly collisional, near-sonic plasma in a diverging magnetic nozzle. The model assumes cold, partially magnetized ions and hot, isothermal, fully magnetized electrons. Different conditions of the plasma beam at the nozzle throat are considered. A central feature is that a positive thrust gain in the nozzle of a plasma thruster is intimately related to the azimuthal current in the plasma being diamagnetic. Then, and contrary to existing expectations, the three aforementioned detachment mechanisms are divergent, that is, the plasma beam diverges outwards of the guide nozzle, further hindering its axial expansion and the thrust efficiency. The rate of divergent detachment is quantified for the small-parameter range of the three mechanisms. Alternative mechanisms for a convergent detachment of the plasma beam are suggested.

  14. Characteristics of divertor detachment for ITER conditions

    NASA Astrophysics Data System (ADS)

    Kukushkin, A. S.; Pacher, H. D.; Pitts, R. A.

    2015-08-01

    The relative role of particle balance vs. momentum balance in the phenomenon of divertor plasma detachment in tokamaks is re-assessed. Ion removal from the plasma flow by volumetric recombination and/or cross-field transport is identified as the key element in the formation of the rollover of the ion saturation current on the targets, whereas "momentum removal" (friction) is responsible for maintaining high plasma pressure upstream. The deterioration of neutral particle confinement in the divertor as particle throughput increases is the primary cause of the solution collapse typically seen when deep detachment is modelled for present day experiments.

  15. Divertor plasma detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, S. I.; Kukushkin, A. S.; Pshenov, A. A.

    2016-05-01

    Regime with the plasma detached from the divertor targets (detached divertor regime) is a natural continuation of the high recycling conditions to higher density and stronger impurity radiation loss. Both the theoretical considerations and experimental data show clearly that the increase of the impurity radiation loss and volumetric plasma recombination causes the rollover of the plasma flux to the target when the density increases, which is the manifestation of detachment. Plasma-neutral friction (neutral viscosity effects), although important for the sustainment of high density/pressure plasma upstream and providing the conditions for efficient recombination and power loss, is not directly involved in the reduction of the plasma flux to the targets. The stability of detachment is also discussed.

  16. Retinal detachment in pseudophakia.

    PubMed

    Galin, M A; Poole, T A; Obstbaum, S A

    1979-07-01

    In a series of cataract patients excluding myopic individuals, under age 60 years, and cases in which vitreous loss occurred, retinal detachment was no less frequent after intracapsular cataract extraction and Sputnik iris supported lenses than in controls. Both groups were followed up for a minimum of two years. The detachments predominantly occurred from retinal breaks in areas of the retina that looked normal preoperatively. PMID:464014

  17. Plume detachment from a magnetic nozzle

    SciTech Connect

    Deline, Christopher A.; Bengtson, Roger D.; Breizman, Boris N.; Tushentsov, Mikhail R.; Jones, Jonathan E.; Chavers, D. Greg; Dobson, Chris C.; Schuettpelz, Branwen M.

    2009-03-15

    High-powered electric propulsion thrusters utilizing a magnetized plasma require that plasma exhaust detach from the applied magnetic field in order to produce thrust. This paper presents experimental results demonstrating that a sufficiently energetic and flowing plasma can indeed detach from a magnetic nozzle. Microwave interferometer and probe measurements provide plume density, electron temperature, and ion flux measurements in the nozzle region. Measurements of ion flux show a low-beta plasma plume which follows applied magnetic field lines until the plasma kinetic pressure reaches the magnetic pressure and a high-beta plume expanding ballistically afterward. Several magnetic configurations were tested including a reversed field nozzle configuration. Despite the dramatic change in magnetic field profile, the reversed field configuration yielded little measurable change in plume trajectory, demonstrating the plume is detached. Numerical simulations yield density profiles in agreement with the experimental results.

  18. Dynamical processes in heavy ion reactions

    SciTech Connect

    Blann, M.; Remington, B.A.

    1988-07-25

    In this report I review the physical assumptions of the Boltzmann Master Equation (BME). Comparisons of the model with experimental neutron spectra gated on evaporation residues for a range of incident projectile energies and masses are presented; next, I compare n spectra gated on projectile-like fragments, followed by comparisons with ungated, inclusive proton spectra. I will then consider secondary effects from the nucleon-nucleon processes involved in the heavy ion relaxation processes, specifically the high energy ..gamma..-rays which have been observed at energies up to 140 MeV in collisions of heavy ions of 20/endash/84 MeV/..mu... Another secondary effect, subthreshold pion production, was covered in the XVII School and will not be repeated. 39 refs., 16 figs.

  19. Trapped Atomic Ions and Quantum Information Processing

    SciTech Connect

    Wineland, D. J.; Leibfried, D.; Bergquist, J. C.; Blakestad, R. B.; Bollinger, J. J.; Britton, J.; Chiaverini, J.; Epstein, R. J.; Hume, D. B.; Itano, W. M.; Jost, J. D.; Koelemeij, J. C. J.; Langer, C.; Ozeri, R.; Reichle, R.; Rosenband, T.; Schaetz, T.; Schmidt, P. O.; Seidelin, S.; Shiga, N.

    2006-11-07

    The basic requirements for quantum computing and quantum simulation (single- and multi-qubit gates, long memory times, etc.) have been demonstrated in separate experiments on trapped ions. Construction of a large-scale information processor will require synthesis of these elements and implementation of high-fidelity operations on a very large number of qubits. This is still well in the future. NIST and other groups are addressing part of the scaling issue by trying to fabricate multi-zone arrays of traps that would allow highly-parallel and scalable processing. In the near term, some simple quantum processing protocols are being used to aid in quantum metrology, such as in atomic clocks. As the number of qubits increases, Schroedinger's cat paradox and the measurement problem in quantum mechanics become more apparent; with luck, trapped ion systems might be able to shed light on these fundamental issues.

  20. Experimental characterization and atomistic modeling of interfacial void formation and detachment in short pulse laser processing of metal surfaces covered by solid transparent overlayers

    NASA Astrophysics Data System (ADS)

    Karim, Eaman T.; Shugaev, Maxim V.; Wu, Chengping; Lin, Zhibin; Matsumoto, Hisashi; Conneran, Maria; Kleinert, Jan; Hainsey, Robert F.; Zhigilei, Leonid V.

    2016-04-01

    The short pulse laser interaction with metal surfaces covered by solid transparent overlayers is investigated in experiments and atomistic simulations, with a particular aim of revealing the mechanisms responsible for structural modification of the metal-overlayer interfacial regions. Experimental characterization of Al-silica targets modified by single-pulse laser irradiation with the pulse duration of 10 ps reveals the transitions from the generation of extended interfacial voids with internal nanoscale surface roughness to the partial detachment of the overlayer from the metal substrate, and to the cracking/chipping or complete removal of the overlayer as the laser fluence increases. The mechanisms responsible for the appearance, growth, and percolation of the interfacial voids leading to the detachment of the overlayer from the metal substrate are investigated in a large-scale atomistic simulation. The results of the simulation demonstrate that the processes of nucleation and growth of the interfacial voids are driven by the dynamic relaxation of laser-induced stresses proceeding simultaneously with rapid phase transformations and temperature variation in the interfacial region. The growth and coalescence of the interfacial voids results in the formation of liquid bridges connecting the overlayer and the metal substrate, whereas solidification of the transient liquid structures produced by the breakup of the liquid bridges may be responsible for the formation of the nanoscale roughness of the interfacial voids observed in experiments. Computational analysis of the effect of preexisting interfacial voids reveals a complex dynamic picture of the initial expansion and subsequent compaction of the surface region of the metal substrate and suggests a possible scenario for the formation of voids below the metal-overlayer interface.

  1. Quantum Information Processing with Trapped Ions

    SciTech Connect

    Barrett, M.D.; Schaetz, T.; Chiaverini, J.; Leibfried, D.; Britton, J.; Itano, W.M.; Jost, J.D.; Langer, C.; Ozeri, R.; Wineland, D.J.; Knill, E.

    2005-05-05

    We summarize two experiments on the creation and manipulation of multi-particle entangled states of trapped atomic ions - quantum dense coding and quantum teleportation. The techniques used in these experiments constitute an important step toward performing large-scale quantum information processing. The techniques also have application in other areas of physics, providing improvement in quantum-limited measurement and fundamental tests of quantum mechanical principles, for example.

  2. ION EXCHANGE ADSORPTION PROCESS FOR PLUTONIUM SEPARATION

    DOEpatents

    Boyd, G.E.; Russell, E.R.; Taylor, M.D.

    1961-07-11

    Ion exchange processes for the separation of plutonium from fission products are described. In accordance with these processes an aqueous solution containing plutonium and fission products is contacted with a cation exchange resin under conditions favoring adsorption of plutonium and fission products on the resin. A portion of the fission product is then eluted with a solution containing 0.05 to 1% by weight of a carboxylic acid. Plutonium is next eluted with a solution containing 2 to 8 per cent by weight of the same carboxylic acid, and the remaining fission products on the resin are eluted with an aqueous solution containing over 10 per cent by weight of sodium bisulfate.

  3. Signal processing for ION mobility spectrometers

    NASA Technical Reports Server (NTRS)

    Taylor, S.; Hinton, M.; Turner, R.

    1995-01-01

    Signal processing techniques for systems based upon Ion Mobility Spectrometry will be discussed in the light of 10 years of experience in the design of real-time IMS. Among the topics to be covered are compensation techniques for variations in the number density of the gas - the use of an internal standard (a reference peak) or pressure and temperature sensors. Sources of noise and methods for noise reduction will be discussed together with resolution limitations and the ability of deconvolution techniques to improve resolving power. The use of neural networks (either by themselves or as a component part of a processing system) will be reviewed.

  4. Plasma immersion ion implantation for silicon processing

    NASA Astrophysics Data System (ADS)

    Yankov, Rossen A.; Mändl, Stephan

    2001-04-01

    Plasma Immersion Ion Implantation (PIII) is a technology which is currently widely investigated as an alternative to conventional beam line implantation for ultrashallow doping beyond the 0.15 m technology. However, there are several other application areas in modern semiconductor processing. In this paper a detailed discussion of the PIII process for semiconductors and of actual as well as future applications is given. Besides the well known advantages of PIII - fast process, implantation of the whole surface, low cost of ownership - several peculiarities - like spread of the implantation energy due to finite rise time or collisions, no mass separation, high secondary electron emission - must be mentioned. However, they can be overcome by adjusting the system and the process parameters. Considering the applications, ultrashallow junction formation by PIII is an established industrial process, whereas SIMOX and Smart-Cut by oxygen and hydrogen implantation are current topics between research and introduction into industry. Further applications of PIII, of which some already are research topics and some are only investigated by conventional ion implantation, include seeding for metal deposition, gettering of metal impurities, etch stop layers and helium implantation for localized lifetime control.

  5. Process analysis using ion mobility spectrometry.

    PubMed

    Baumbach, J I

    2006-03-01

    Ion mobility spectrometry, originally used to detect chemical warfare agents, explosives and illegal drugs, is now frequently applied in the field of process analytics. The method combines both high sensitivity (detection limits down to the ng to pg per liter and ppb(v)/ppt(v) ranges) and relatively low technical expenditure with a high-speed data acquisition. In this paper, the working principles of IMS are summarized with respect to the advantages and disadvantages of the technique. Different ionization techniques, sample introduction methods and preseparation methods are considered. Proven applications of different types of ion mobility spectrometer (IMS) used at ISAS will be discussed in detail: monitoring of gas insulated substations, contamination in water, odoration of natural gas, human breath composition and metabolites of bacteria. The example applications discussed relate to purity (gas insulated substations), ecology (contamination of water resources), plants and person safety (odoration of natural gas), food quality control (molds and bacteria) and human health (breath analysis). PMID:16132133

  6. VANISHING RETINAL DETACHMENT

    PubMed Central

    2015-01-01

    Purpose: The purpose of this report is to describe a case of rhegmatogenous retinal detachment in the setting of chronic kidney disease that exhibited complete retinal reattachment after serial hemodialysis. Methods: Retrospective case report. Results: A 58-year-old woman with acute vision loss was found to have a macula-involving rhegmatogenous retinal detachment. Due to chronic kidney disease, she continued with routinely scheduled hemodialysis for 1 week until surgical clearance was obtained. Preoperative examination revealed complete reattachment of the retina with a persistent retinal tear. Barrier laser was applied to the tear and the retina remained attached until the most recent follow-up 8 months later. The workup of alternate etiologies was unrevealing. Conclusion: This case describes a temporal association between hemodialysis and resolution of subretinal fluid due to rhegmatogenous retinal detachment. A potential causal linkage is suggested based on shifting fluid dynamics associated with hemodialysis. A shift in treatment paradigm is not advised. PMID:26352323

  7. Ouabain enhances lung cancer cell detachment.

    PubMed

    Ruanghirun, Thidarat; Pongrakhananon, Varisa; Chanvorachote, Pithi

    2014-05-01

    A human steroid hormone, ouabain, has been shown to play a role in several types of cancer cell behavior; however, its effects on cancer metastasis are largely unknown. Herein, we demonstrate that sub-toxic concentrations of ouabain facilitate cancer cell detachment from the extracellular matrix in human lung cancer cells. Ouabain at concentrations of 0-10 pM significantly enhanced cell detachment in dose- and time- dependent manners, while having minimal effect on cell viability. The detachment-inducing effect of ouabain was found to be mediated through focal-adhesion kinase and ATP-dependent tyrosine kinase pathways. Alpha-5 and beta-1 integrins were found to be down-regulated in response to ouabain treatment. Since detachment of cancer cells is a prerequisite process for metastasis to begin, these insights benefit our understanding over the molecular basis of cancer biology. PMID:24778025

  8. Detached rock evaluation device

    DOEpatents

    Hanson, David R.

    1986-01-01

    A rock detachment evaluation device (10) having an energy transducer unit 1) for sensing vibrations imparted to a subject rock (172) for converting the sensed vibrations into electrical signals, a low band pass filter unit (12) for receiving the electrical signal and transmitting only a low frequency segment thereof, a high band pass filter unit (13) for receiving the electrical signals and for transmitting only a high frequency segment thereof, a comparison unit (14) for receiving the low frequency and high frequency signals and for determining the difference in power between the signals, and a display unit (16) for displaying indicia of the difference, which provides a quantitative measure of rock detachment.

  9. Photodetachment process for beam neutralization

    DOEpatents

    Fink, Joel H. [Livermore, CA; Frank, Alan M. [Livermore, CA

    1979-02-20

    A process for neutralization of accelerated ions employing photo-induced charge detachment. The process involves directing a laser beam across the path of a negative ion beam such as to effect photodetachment of electrons from the beam ions. The frequency of the laser beam employed is selected to provide the maximum cross-section for the photodetachment process.

  10. Photodetachment process for beam neutralization

    DOEpatents

    Fink, J.H.; Frank, A.M.

    1979-02-20

    A process for neutralization of accelerated ions employing photo-induced charge detachment is disclosed. The process involves directing a laser beam across the path of a negative ion beam such as to effect photodetachment of electrons from the beam ions. The frequency of the laser beam employed is selected to provide the maximum cross-section for the photodetachment process. 2 figs.

  11. Industrialization of the ion plating process

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1976-01-01

    A new process referred to as ion plating by induction heating (IPIH) is described, which combines the advantages of both ion plating and induction heating. The IPIH apparatus consists of the specimen (cathode) to be coated and the evaporation heating source, which is a ceramic crucible containing the metal to be heated. The specimen is an internal part of the high-voltage ceramic-metal vacuum feedthrough and is connected to the negative terminal of the high-voltage power supply, the positive terminal of the power supply being grounded. The plating conditions are the same as those most commonly used in industrial ion plating. A number of metals - such as nickel, iron, platinum - which were practically impossible to deposit by resistance heating evaporation can now be effectively evaporated and deposited to any desired thickness. Excellent adherence is observed for many metals deposited on various metal surfaces in thicknesses from 0.15 to 50 microns, regardless of the materials selected for coating and substrate.

  12. Measurements of single-electron detachment cross-sections for Cu- and Ag- in collision with He and N2

    NASA Astrophysics Data System (ADS)

    Zhang, Xuemei; Wu, Shimin; Li, Guangwu; Lu, Fuquan; Tang, Jiayong; Yang, Fujia

    2001-12-01

    Electron detachment of negative ions, in collision with a static gas target, is known to be one of the most fundamental processes occurring in negative-ion-atom collisions. The experimental results of cross-section data for transition element ions in collision with gases are of great interest not only for their potential application value, but also as a challenge to a theoretical study of complex negative ions in collision with atoms or molecules. In the present work, the single-electron detachment (SED) cross-sections for Cu- and Ag- in collision with He, N2 have been obtained in the energy region of 10-30 keV. By using a single-particle detector for both neutral atoms and ions, the experimental uncertainty of the results is improved in this work.

  13. Neutralization of a fast negative-ion beam

    SciTech Connect

    Schlachter, A.S.; Mowat, J.R.; Stearns, J.W.; Gohil, P.; Pyle, R.V.

    1986-01-01

    Neutralization of a fast negative-ion beam, primarily H/sup -/, is discussed in terms of competing one- and two-electron detachment processes in a variety of media: gas (vapor), plasma, liquid sheet, solid foil.

  14. Measurement of electronegativity at different laser wavelengths: accuracy of Langmuir probe assisted laser photo-detachment

    NASA Astrophysics Data System (ADS)

    Sirse, N.; Oudini, N.; Bendib, A.; Ellingboe, A. R.

    2016-08-01

    Langmuir probe (LP) assisted pulsed laser photo-detachment (LPD) of negative ions is one of the frequently used diagnostic techniques in electronegative plasmas. The technique is based on measuring the rise in electron saturation current following photo-detachment. During the photo-detachment process it is assumed that the background electron parameters (temperature and density) remain unchanged in the laser channel and the photo-detached electrons thermalize instantaneously with the background electrons (same temperature). Therefore, the measured electronegativity should be independent of laser wavelengths. However, our recent simulation results (2015 Phys. Plasmas 22 073509) demonstrates a failure of these assumptions and suggests that the measured rise in electron saturation current has a dependence on the laser wavelength. This letter presents experimental evidence in support of these simulation results. In this work, photo-detachment is performed at two different laser wavelengths in an oxygen inductively coupled plasma discharge. Electronegativity measured by LP assisted LPD is compared with those obtained by the hairpin probe (HPP) assisted LPD which is based on quasi-neutrality assumption. The experimental results reveal that the electronegativities measured by LP assisted LPD are affected by the laser wavelength, whereas, electronegativities measured by HPP assisted LPD are almost independent. The discrepancy between the measurements is higher at high electronegativities. In conclusion, the experimental results validate the weakness of assumptions to estimate electronegativity from LPD combined with LP and therefore emphasizes the need of a more realistic model to analyze raw data or an alternate solution is to utilize HPP.

  15. Materials processing with intense pulsed ion beams

    SciTech Connect

    Rej, D.J.; Davis, H.A.; Olson, J.C.

    1996-12-31

    We review research investigating the application of intense pulsed ion beams (IPIBs) for the surface treatment and coating of materials. The short range (0.1-10 {mu}m) and high-energy density (1-50 J/cm{sup 2}) of these short-pulsed ({le} 1 {mu}s) beams (with ion currents I = 5 - 50 kA, and energies E = 100 - 1000 keV) make them ideal to flash-heat a target surface, similar to the more familiar pulsed laser processes. IPIB surface treatment induces rapid melt and solidification at up to 10{sup 10} K/s to cause amorphous layer formation and the production of non-equilibrium microstructures. At higher energy density the target surface is vaporized, and the ablated vapor is condensed as coatings onto adjacent substrates or as nanophase powders. Progress towards the development of robust, high-repetition rate IPIB accelerators is presented along with economic estimates for the cost of ownership of this technology.

  16. Prompt processes in heavy ion reactions

    SciTech Connect

    Blann, M.; Remington, B.A.

    1987-12-01

    We test a relaxation model based on two body nucleon-nucleon scattering processes to interpret phenomena observed in heavy ion reactions. We use the Boltzmann Master Equation to accomplish this. By assuming that the projectile nucleons partition the total excitation with equal a-priori probability of all configurations, we are able to reproduce several sets of neutron spectra from /sup 20/Ne and /sup 12/C induced reactions on /sup 165/Ho and from reactions of /sup 40/Ar or /sup 40/Ca. We point out ambiguities in deducing angle-integrated energy spectra from double differential spectra. With no additional free parameters, our model successfully reproduces a large body of high energy ..gamma..-ray spectra by assuming an incoherent n-p-bremsstrahlung mechanism. 45 refs., 13 figs.

  17. An atmospheric process to explain the formation of the detached layers of dust on Mars: GCM modelling, validation and comparison with observations

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Bertrand, Tanguy; Forget, François; Spiga, Aymeric; Millour, Ehouarn

    2015-04-01

    Dust is the crucial component of the Martian atmosphere. Its motion, horizontal and vertical transportation, is of great importance to Martian meteorology and climate. Recently, detached layers of dust are confirmed by the observations of the Mars Climate Sounder (MCS) as well as the Thermal Emission Spectrometer (TES). The origin of the detached layers has remained debated. They cannot be reproduced by traditional Global Climate Models (GCM) including a dust cycle. Several possible interpretations were proposed to explain the origins of the detached layers of dust, such as small-scale dust lifting, upslope topographic winds, scavenging by water ice clouds, dust storms... Scavenging has been shown to be unable to form of dust detached layer through the simulations using the GCM developed at the Laboratoire de Météorologie Dynamique (LMD). In the present study, a new parameterization called 'rocket dust storms' in the LMD Martian GCM were implemented on the basis of mesoscale model simulations. The parameterization works like this: In the GCM, when a strong dust opacity gradient is observed, a local (subgrid scale) dust storm will be produced. Because of the difference of radiative heating rates between inside and outside of the dust storm, the dust particles inside the dust storm will be transported to high altitudes due to the vertical velocity of the dust which is directly deduced from the extra dust radiative heating, since we have found that this heating is almost integrally converted to adiabatic heating . The dust particles injected in the high layers are then horizontally transported by the large scale winds in the GCM. In the present study, the validation of the 'rocket dust storm' parameterization and the comparison between model outputs and MCS observations is implemented. To do so, case studies of the dust storm are performed to see how the dust were lifted and transported and how the detached layers formed in the upper atmosphere. We find that the

  18. Retinal detachment associated with atopic dermatitis.

    PubMed Central

    Takahashi, M; Suzuma, K; Inaba, I; Ogura, Y; Yoneda, K; Okamoto, H

    1996-01-01

    BACKGROUND: Retinal detachment associated with atopic dermatitis, one of the most common forms of dermatitis in Japan, has markedly increased in Japan in the past 10 years. To clarify pathogenic mechanisms of retinal detachment in such cases, we retrospectively studied clinical characteristics of retinal detachment associated with atopic dermatitis. METHODS: We examined the records of 80 patients (89 eyes) who had retinal detachment associated with atopic dermatitis. The patients were classified into three groups according to lens status: group A, eyes with clear lenses (40 eyes); group B, eyes with cataract (38 eyes), and group C, aphakic or pseudophakic eyes (11 eyes). RESULTS: No significant differences were noted in the ratio of males to females, age distribution, refractive error, or characteristic of retinal detachment among the three groups. The types of retinal breaks, however, were different in eyes with and without lens changes. While atrophic holes were dominant in group A, retinal dialysis was mainly seen in groups B and C. CONCLUSION: These findings suggested that anterior vitreoretinal traction may play an important role in the pathogenesis of retinal breaks in eyes with atopic cataract and that the same pathological process may affect the formation of cataract and tractional retinal breaks in patients with atopic dermatitis. PMID:8664234

  19. Effects of van der Waals forces and salt ions on the growth of water films on ice and the detachment of CO2 bubbles

    NASA Astrophysics Data System (ADS)

    Thiyam, P.; Lima, E. R. A.; Malyi, O. I.; Parsons, D. F.; Buhmann, S. Y.; Persson, C.; Boström, M.

    2016-02-01

    We study the effect of salts on the thickness of wetting films on melting ice and interactions acting on CO2 bubble near ice-water and vapor-water interfaces. Governing mechanisms are the Lifshitz and the double-layer interactions in the respective three-layer geometries. We demonstrate that the latter depend on the Casimir-Polder interaction of the salt ions dissolved in water with the respective ice, vapor and CO2 interfaces, as calculated using different models for their effective polarizability in water. Significant variation in the predicted thickness of the equilibrium water film is observed for different salt ions and when using different models for the ions' polarizabilities. We find that CO2 bubbles are attracted towards the ice-water interface and repelled from the vapor-water interface.

  20. Secondary ion coincidence in highly charged ion based secondary ion mass spectroscopy for process characterization

    SciTech Connect

    Hamza, A.V.; Schenkel, T.; Barnes, A.V.; Schneider, D.H.

    1999-01-01

    Coincidence counting in highly charged ion based secondary ion mass spectroscopy has been applied to the characterization of selective tungsten deposition via disilane reduction of tungsten hexafluoride on a patterned SiO{sub 2}/Si wafer. The high secondary ion yield and the secondary ion emission from a small area produced by highly charged ions make the coincidence technique very powerful.

  1. Sediment detachment by rain power

    NASA Astrophysics Data System (ADS)

    Gabet, Emmanuel J.; Dunne, Thomas

    2003-01-01

    In interrill areas, overland flow is often incapable of detaching soil particles so detachment is primarily by raindrop impact. We derive a mathematical expression, rain power (R, W m-2), relating the energy expenditure of raindrops impacting a soil surface to the rate of detachment of soil particles. Rain power incorporates rainfall, hillslope, and vegetation characteristics and is modulated by flow depths. Rainfall simulation experiments on natural hillslopes were performed to measure detachment rates and across-slope flow depth distributions in surface runoff. Our results indicate that flow depths follow a Poisson distribution, and this observation is used to develop a dimensionless function, A(?, d), that accounts for the interaction of flow depths (h) and raindrop diameter (d) in moderating detachment rates. Rain power correlates well with the detachment rate of fine-grained particles (ψ, g m-2 s-1) so that ψ = 0.011R1.4A(?, d) (n = 44, R2 = 0.88, p < 0.005). We generalize this result to represent natural rainfall conditions and present a method for modeling sediment detachment rates and sediment discharge along entire lengths of hillslopes under the range of conditions where detached sediment is transported as wash load. Modeling simulations demonstrate the temporal and spatial variation in detachment rates caused by increases in flow depth.

  2. Dynamic stability of detached solidification

    NASA Astrophysics Data System (ADS)

    Mazuruk, K.; Volz, M. P.

    2016-06-01

    A dynamic stability analysis model is developed for meniscus-defined crystal growth processes. The Young-Laplace equation is used to analyze the response of a growing crystal to perturbations to its radius and a thermal transport model is used to analyze the effect of perturbations on the evolution of the crystal-melt interface. A linearized differential equation is used to analyze radius perturbations but a linear integro-differential equation is required for the height perturbations. The stability model is applied to detached solidification under zero-gravity and terrestrial conditions. A numerical analysis is supplemented with an approximate analytical analysis, valid in the limit of small Bond numbers. For terrestrial conditions, a singularity is found to exist in the capillary stability coefficients where, at a critical value of the pressure differential across the meniscus, there is a transition from stability to instability. For the zero-gravity condition, exact formulas for the capillary stability coefficients are derived.

  3. High-Speed Nano-Processing with Cluster Ion Beams

    NASA Astrophysics Data System (ADS)

    Seki, T.; Matsuo, J.

    2006-11-01

    The gas cluster ion beam process has a high potential for material processing in nano-technology devices, such as photonic crystals, thin film transistors (TFTs) and micro-electromechanical systems (MEMS). In order to fabricate the devices, one needs to etch target materials with a high-speed, low-damage and ultra-smooth process. Extremely high rate sputtering was realized by high-energy cluster ion beam. We have been using this technique for poly-Si TFTs. There are many hillocks on poly-Si films formed by using a laser anneal technique, and they cause degradation of devices. When the laser crystallized poly-Si film was irradiated with cluster ion beam, the higher hillocks could be etched selectively and the surfaces of poly-Si films could be processed with low ion dose. High-speed nano-processing was realized by cluster ion beam.

  4. Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

    DOEpatents

    Dietz, Mark L.; Horwitz, E. Philip; Bartsch, Richard A.; Barrans, Jr., Richard E.; Rausch, David

    1999-01-01

    A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution.

  5. Composition and process for separating cesium ions from an acidic aqueous solution also containing other ions

    DOEpatents

    Dietz, M.L.; Horwitz, E.P.; Bartsch, R.A.; Barrans, R.E. Jr.; Rausch, D.

    1999-03-30

    A crown ether cesium ion extractant is disclosed as is its synthesis. The crown ether cesium ion extractant is useful for the selective purification of cesium ions from aqueous acidic media, and more particularly useful for the isolation of radioactive cesium-137 from nuclear waste streams. Processes for isolating cesium ions from aqueous acidic media using the crown ether cesium extractant are disclosed as are processes for recycling the crown ether cesium extractant and processes for recovering cesium from a crown ether cesium extractant solution. 4 figs.

  6. Three-dimensional necking during viscous slab detachment

    NASA Astrophysics Data System (ADS)

    Tscharner, M.; Schmalholz, S. M.; Duretz, T.

    2014-06-01

    We study the three-dimensional (3-D) deformation during detachment of a lithospheric slab with simple numerical models using the finite element method. An initially vertical layer of power law viscous fluid mimics the slab and is surrounded by a linear or power law viscous fluid representing asthenospheric mantle. We quantify the impact of slab size and shape (symmetric/asymmetric) on slab detachment and identify two processes that control the lateral (i.e., along-trench) slab deformation: (1) the horizontal deflection of the lateral, vertical slab sides (> 100 km with velocities up to 16 mm/yr) and (2) the propagation of localized thinning (necking) inside the slab (with velocities >9 cm/yr). The lateral propagation velocity is approximately constant during slab detachment. Larger slabs (here wider than approximately 300 km) detach with rates similar to those predicted by 2-D models, whereas smaller slabs detach slower. Implications for geodynamic processes and interpretations of seismic tomography are discussed.

  7. Two-dimensional simulations of surface deformation caused by slab detachment

    NASA Astrophysics Data System (ADS)

    Buiter, Susanne J. H.; Govers, Rob; Wortel, M. J. R.

    2002-09-01

    Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth's surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where detachment is expected. In this study, we quantify surface deformation caused by detachment of subducted lithosphere. We determine the range of displacement magnitudes which can be associated with slab detachment using numerical models. The lithospheric plates in our models have an effective elastic thickness, which provides an upper bound for rapid processes, like slab detachment, to the surface deformation of lithosphere with a more realistic rheology. The surface topography which develops during subduction is compared with the topography shortly after detachment is imposed. Subduction with a non-migrating trench system followed by detachment leads to a maximum surface uplift of 2-6 km, while this may be higher for the case of roll-back preceding detachment. In the latter situation, the back-arc basin may experience a phase of compression after detachment. Within the context of our elastic model, the surface uplift resulting from slab detachment is sensitive to the depth of detachment, a change in friction on the subduction fault during detachment and viscous stresses generated by sinking of the detached part of the slab. Overall, surface uplift of these magnitudes is not diagnostic of slab detachment since variations during ongoing subduction may result in similar vertical surface displacements.

  8. Measurements of scattering processes in negative ion: Atom collisions. Technical progress report, 1 September 1991--31 December 1994

    SciTech Connect

    Kvale, T.J.

    1994-09-27

    This report describes the progress made on the research objectives during the past three years of the grant. This research project is designed to study various scattering processes which occur in H{sup {minus}} collisions with atomic (specifically, noble gas and atomic hydrogen) targets in the intermediate energy region. These processes include: elastic scattering, single- and double-electron detachment, and target excitation/ionization. For the elastic and target inelastic processes where H{sup {minus}} is scattered intact, the experimental technique of Ion Energy-Loss Spectroscopy (IELS) will be employed to identify the final target state(s). In most of the above processes, cross sections are unknown both experimentally and theoretically. The measurements will provide total cross sections (TCS) initially, and once the angular positioning apparatus is installed, will provide angular differential cross sections (ADCS).

  9. Electrically induced drop detachment and ejection

    NASA Astrophysics Data System (ADS)

    Cavalli, Andrea; Preston, Daniel J.; Tio, Evelyn; Martin, David W.; Miljkovic, Nenad; Wang, Evelyn N.; Blanchette, Francois; Bush, John W. M.

    2016-02-01

    A deformed droplet may leap from a solid substrate, impelled to detach through the conversion of surface energy into kinetic energy that arises as it relaxes to a sphere. Electrowetting provides a means of preparing a droplet on a substrate for lift-off. When a voltage is applied between a water droplet and a dielectric-coated electrode, the wettability of the substrate increases in a controlled way, leading to the spreading of the droplet. Once the voltage is released, the droplet recoils, due to a sudden excess in surface energy, and droplet detachment may follow. The process of drop detachment and lift-off, prevalent in both biology and micro-engineering, has to date been considered primarily in terms of qualitative scaling arguments for idealized superhydrophobic substrates. We here consider the eletrically-induced ejection of droplets from substrates of finite wettability and analyze the process quantitatively. We compare experiments to numerical simulations and analyze how the energy conversion efficiency is affected by the applied voltage and the intrinsic contact angle of the droplet on the substrate. Our results indicate that the finite wettability of the substrate significantly affects the detachment dynamics, and so provide new rationale for the previously reported large critical radius for drop ejection from micro-textured substrates.

  10. Polymer processing by a low energy ion accelerator

    NASA Astrophysics Data System (ADS)

    Lorusso, A.; Velardi, L.; Nassisi, V.; Paladini, F.; Visco, A. M.; Campo, N.; Torrisi, L.; Margarone, D.; Giuffrida, L.; Rainò, A.

    2008-05-01

    Ion implantation is a process in which ions are accelerated toward a substrate at energies high enough to bury them just below the surface substrate in order to modify the surface characteristics. Laser-produced plasma is a very suitable and low cost technique in the production of ion sources. In this work, a laser ion source is developed by a UV pulsed laser of about 108 W/cm2 power density, employing a C target and a post ion acceleration of 40 kV to increase the ion energy. In this work, we implanted C ions on ultra-high-molecular-weight-polyethylene (UHMWPE) and low-density polyethylene (LDPE). We present the preliminary results of surface property modifications for both samples. In particular, we have studied the modifications of the surface micro-hardness of the polymers by applying the "scratch test" method as well as the hydrophilicity modifications by the contact angle measurements.

  11. Numerical simulation of plasma processes driven by transverse ion heating

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Chan, C. B.

    1993-01-01

    The plasma processes driven by transverse ion heating in a diverging flux tube are investigated with numerical simulation. The heating is found to drive a host of plasma processes, in addition to the well-known phenomenon of ion conics. The downward electric field near the reverse shock generates a doublestreaming situation consisting of two upflowing ion populations with different average flow velocities. The electric field in the reverse shock region is modulated by the ion-ion instability driven by the multistreaming ions. The oscillating fields in this region have the possibility of heating electrons. These results from the simulations are compared with results from a previous study based on a hydrodynamical model. Effects of spatial resolutions provided by simulations on the evolution of the plasma are discussed.

  12. Detachment of Sessile Droplets in Immiscible Fluids Using Electrowetting

    NASA Astrophysics Data System (ADS)

    Hong, Jiwoo; Lee, Sang Joon

    2014-11-01

    The detachment (or removal) of droplets from a solid surface is an indispensable process in numerous practical applications. Here we firstly detach sessile droplets in immiscible fluids from a hydrophobic surface by electrowetting. The critical conditions for droplet detachment are determined by exploring the retracting dynamics for a wide range of driving voltages and physical properties of fluids. The relationships between physical parameters and dynamic characteristics of retracting and jumping droplets, such as contact time and jumping height, are also established. The threshold voltage for droplet detachment in oil with high viscosity is largely reduced by electrowetting actuations with a square pulse. Finally, by using DC and AC electrowetting actuations, we demonstrate the detachment of oil droplets with very low contact angle on a hydrophobic surface in water.

  13. One- and two-photon detachment of O-

    NASA Astrophysics Data System (ADS)

    Génévriez, Matthieu; Urbain, Xavier; Dochain, Arnaud; Cyr, Alain; Dunseath, Kevin M.; Terao-Dunseath, Mariko

    2016-08-01

    Cross sections for one- and two-photon detachment of O-(1 s22 s22 p5P2o) have been determined in a joint experimental and theoretical study. The absolute measurement is based on the animated-crossed-beam technique, which is extended to the case of pulsed lasers, pulsed ion beams, and multiphoton detachment. The ab initio calculations employ R -matrix Floquet theory, with simple descriptions of the initial bound state and the residual oxygen atom which reproduce well the electron affinity and ground-state polarizability. For one-photon detachment, the measured and computed cross sections are in good mutual agreement, departing significantly from previous reference experiments and calculations. The generalized two-photon detachment cross section, measured at the Nd:YAG laser wavelength, is in good agreement with the R -matrix Floquet calculations. Long-standing discrepancies between theory and experiment are thus resolved.

  14. Balancing engagement/detachment in AIDS-related multiple losses.

    PubMed

    Carmack, B J

    1992-01-01

    The process gay persons use to manage the multiple losses and cumulative grief from losing lovers, friends, colleagues and clients to AIDS was explored. Interviews with gay individuals (n = 19) in a large urban area in the West provided data for conceptual coding and comparative analysis. Balancing engagement and detachment was identified as the basic social-psychological process that described how gay individuals struggled to reach an optimal balance in their involvement in the needs of individuals and the community. Four conceptual categories were identified: dysfunctional engagement, functional engagement, functional detachment and dysfunctional detachment. These four categories occur within the contexts of previous life style and redefinition of personal values. PMID:1541482

  15. Status and directions of modified tribological surfaces by ion processes

    NASA Technical Reports Server (NTRS)

    Spalvins, Talivaldis

    1988-01-01

    An overview is presented of recent advances in modifying contacting surfaces in motion by the various ion assisted surface coating/modification processes to reduce and control tribological failures. The ion assisted coating processes and the surface modification processes offer the greatest potential to custom tailor and optimize the tribological performance. Hard, wear resistant and low shear coatings deposited by the ion assisted processes are discussed. Primarily the recent advances of sputtered MoS2 ion plated Au, Ag, Pb lubricating films and sputtered and ion plated hard, wear resistant TiN, HfN, TiC films are described in terms of structural property performance interrelationships which lead to improved adhesion, cohesion, nucleation, morphological growth, density, film thickness as determined by structural and chemical characterization and frictional and wear behavior. Also, the recent tribological advances using the surface modification processes such as ion implantation, ion beam mixing is discussed with emphasis on the development of lubricous high temperature ceramic surfaces.

  16. PIMASERTIB AND SEROUS RETINAL DETACHMENTS

    PubMed Central

    AlAli, Alaa; Bushehri, Ahmad; Park, Jonathan C.; Krema, Hatem

    2016-01-01

    Purpose: To report a case of multifocal serous retinal detachments associated with pimasertib. Methods: The authors report a 26-year-old patient who developed bilateral multifocal serous retinal detachments appearing 2 days after starting pimasertib (as part of a clinical trial investigating its use in low-grade metastatic ovarian cancer) and rapidly resolving 3 days after stopping it. Conclusion: The mechanism of MEK inhibitor induced visual toxicity remains unclear. The pathophysiology of multifocal serous retinal detachments as a complication of pimasertib is still poorly understood. PMID:26444523

  17. Ion-molecule processes in lasers

    NASA Technical Reports Server (NTRS)

    Laudenslager, J. B.

    1979-01-01

    Three classes of molecular electronic transition lasers produced by hybrid pumping of high pressure rate gas mixtures are discussed. These are (1) rare gas dimer lasers (such as excited Ar2, Kr2, and Xe2) lasing in the VUV, (2) rare gas halide lasers or excimer lasers (such as KrF, ArF, and XeCl excimers) lasing in the UV, and (3) the charge transfer molecular ion laser (such as N2/+/) lasing in the visible range. Laser excitation methods and kinetic sequences are examined for these lasers.

  18. Use of energetic ion beams in materials synthesis and processing

    SciTech Connect

    Appleton, B R

    1991-01-01

    A brief review of the use energetic ion beams and related techniques for the synthesis, processing, and characterization of materials is presented. Selected opportunity areas are emphasized with examples, and references are provided for more extensive coverage.

  19. Simulating data processing for an Advanced Ion Mobility Mass Spectrometer

    SciTech Connect

    Chavarría-Miranda, Daniel; Clowers, Brian H.; Anderson, Gordon A.; Belov, Mikhail E.

    2007-11-03

    We have designed and implemented a Cray XD-1-based sim- ulation of data capture and signal processing for an ad- vanced Ion Mobility mass spectrometer (Hadamard trans- form Ion Mobility). Our simulation is a hybrid application that uses both an FPGA component and a CPU-based soft- ware component to simulate Ion Mobility mass spectrome- try data processing. The FPGA component includes data capture and accumulation, as well as a more sophisticated deconvolution algorithm based on a PNNL-developed en- hancement to standard Hadamard transform Ion Mobility spectrometry. The software portion is in charge of stream- ing data to the FPGA and collecting results. We expect the computational and memory addressing logic of the FPGA component to be portable to an instrument-attached FPGA board that can be interfaced with a Hadamard transform Ion Mobility mass spectrometer.

  20. High-energy ion processing of materials for improved hardcoatings

    SciTech Connect

    Williams, J.M.; Gorbatkin, S.M.; Rhoades, R.L.; Oliver, W.C.; Riester, L.; Tsui, T.Y.

    1994-02-01

    Research has been directed toward use of economically viable ion processing strategies for production and improvement of hardcoatings. Processing techniques were high-energy ion implantation and electron cyclotron resonance microwave plasma processing. Subject materials were boron suboxides, Ti-6Al-4V alloy, CoCrMo alloy (a Stellite{trademark}), and electroplated Cr. These materials may be regarded either as coatings themselves (which might be deposited by thermal spraying, plasma processing, etc.) or in some cases, as substrates whose surfaces can be improved. hardness and other properties in relation to process variables are reported.

  1. Detachable acoustic electric feedthrough

    NASA Astrophysics Data System (ADS)

    Moss, Scott; Skippen, Jeremy; Konak, Michael; Powlesland, Ian; Galea, Steve

    2010-04-01

    This paper outlines the development and characterisation of a detachable acoustic electric feedthrough (DAEF) to transfer power and data across a metal (or composite) plate. The DAEF approach is being explored as a potential means of wirelessly powering in-situ structural health monitoring systems embedded within aircraft and other high value engineering assets. The DAEF technique operates via two axially aligned piezoelectric-magnet structures mounted on opposite sides of a plate. Magnetic force is used to align the two piezoelectric-magnet structures, to create an acoustic path across a plate. The piezoelectric-magnet structures consisted of Pz26 piezoelectric disk elements bonded to NdFeB magnets, with a standard ultrasonic couplant (High-Z) used between the magnet and plate to facilitate the passage of ultrasound. Measured impedance curves are matched to modeled curves using the Comsol multi-physics software coupled with a particle-swarm approach, allowing optimised Pz26 material parameters to be found (i.e. stiffness, coupling and permittivity matrices). The optimised Pz26 parameters are then used in an axi-symmetric Comsol model to make predictions about the DAEF power transfer, which is then experimentally confirmed. With an apparent input power of 1 VA and 4.2 MHz drive frequency, the measured power transfer efficiency across a 1.6 mm Al plate is ~34%. The effect of various system parameters on power transfer is explored, including bondline thickness and plate thickness. DAEF data communication is modelled using LTspice with three-port one-dimensional piezoelectric models, indicating that data rates of 115 kBit/s are feasible.

  2. Retinal detachment repair - series (image)

    MedlinePlus

    ... scleral buckle is applied. This consists of a silicone patch wrapped around the eye, compressing the globe ... of the eye, and sealing the detachment. The silicone patch is usually left in place permanently, unless ...

  3. Detachment of stretched viscoelastic fibrils

    NASA Astrophysics Data System (ADS)

    Glassmaker, N. J.; Hui, C. Y.; Yamaguchi, T.; Creton, C.

    2008-03-01

    New experimental results are presented about the final stage of failure of soft viscoelastic adhesives. A microscopic view of the detachment of the adhesive shows that after cavity growth and expansion, well adhered soft adhesives form a network of fibrils connected to expanded contacting feet which fail via a sliding mechanism, sensitive to interfacial shear stresses rather than by a fracture mechanism as sometimes suggested in earlier work. A mechanical model of this stretching and sliding failure phenomenon is presented which treats the fibril as a nonlinear elastic or viscoelastic rod and the foot as an elastic layer subject to a friction force proportional to the local displacement rate. The force on the stretched rod drives the sliding of the foot against the substrate. The main experimental parameter controlling the failure strain and stress during the sliding process is identified by the model as the normalized probe pull speed, which also depends on the magnitude of the friction and PSA modulus. In addition, the material properties, viscoelasticity and finite extensibility of the polymer chains, are shown to have an important effect on both the details of the sliding process and the ultimate failure strain and stress. Appendix B is only available in electronic form at 10.1140/epje/i2007-10287-y and are accessible for authorised users.

  4. Enhancement of surface processes with low energy ions

    SciTech Connect

    Chason, E.

    1995-05-01

    Continuing trends in device fabrication towards smaller feature sizes, lower thermal budgets and advanced device structures put greater emphasis on controlling the surface structure and reactivity during processing. Since the evolution of the semiconductor surface during processing is determined by the interaction of multiple surface processes, understanding how to control and modify these processes on the atomic level would enable us to exert greater control over the resulting morphology and composition. Low energy ions represent one method for bringing controlled amounts of energy to the surface to modify surface structure and kinetics. The kinetic energy deposited by the ions can break bonds and displace atoms, creating defect populations significantly in excess of the equilibrium concentration. Consequences of these non-equilibrium conditions include the enhancement of surface kinetic processes, increased surface reactivity and formation of metastable structures and compositions. These effects can be beneficial (ion enhanced mass transport can lead to surface smoothing) or they can be detrimental (residual defects can degrade electrical properties or lead to amorphization). The net results depend on a complex balance that depends on many parameters including ion mass, energy, flux and temperature. In the following section, we review progress both in our fundamental understanding of the production of low-energy ion-induced defects and in the use of low energy ions to enhance surface morphology, stimulate low temperature growth and obtain non-equilibrium structures and compositions.

  5. detached_shells_carbon_stars

    NASA Astrophysics Data System (ADS)

    Hony, Sacha; Bouwman, Jeroen; Waters, Laurens

    2004-09-01

    We propose to obtain 19-37 micrometer IRS spectra of the detached shells around nearby carbon-stars. We have selected a small (11) sample of bright, well studied, carbon-stars with known detached shells. The sample covers a range of angular diameters of the detached shells from 8-200" and stellar effective temperatures between 800-2600 K. With the spectra of the dust in the detached shell we aim to establish: i) The location of the shell. ii) The chemistry of the shell in order to constrain it's origin. iii) Test the MgS identification for the ``30'' micrometer emission feature. iv) Determine observationally the relationship between the ``30'' micrometer feature peak-position and the distance to the star. These observations will contribute greatly to the understanding AGB-star mass loss, in general, and the phenomenon of detached shells around carbon-stars, in particular. They will also be used to develop a diagnostic tool that allows to study detached shell properties of distant carbon-stars, that cannot be spatially resolved, based on their IR spectrum alone. The total requested time is 2.5h.

  6. Multiple-electron processes in fast ion-atom collisions

    SciTech Connect

    Schlachter, A.S.

    1989-03-01

    Research in atomic physics at the Lawrence Berkeley Laboratory Super-HILAC and Bevalac accelerators on multiple-electron processes in fast ion-atom collisions is described. Experiments have studied various aspects of the charge-transfer, ionization, and excitation processes. Examples of processes in which electron correlation plays a role are resonant transfer and excitation and Auger-electron emission. Processes in which electron behavior can generally be described as uncorrelated include ionization and charge transfer in high-energy ion-atom collisions. A variety of experiments and results for energies from 1 MeV/u to 420 MeV/u are presented. 20 refs., 15 figs.

  7. Evaluation of negative ion distribution changes by image processing diagnostic

    SciTech Connect

    Ikeda, K. Nakano, H.; Tsumori, K.; Kisaki, M.; Nagaoka, K.; Tokuzawa, T.; Osakabe, M.; Takeiri, Y.; Kaneko, O.; Geng, S.

    2015-04-08

    Distributions of hydrogen Balmer-α (H{sub α}) intensity and its reduction behavior close to a plasma grid (PG) surface have been observed by a spectrally selective imaging system in an arc discharge type negative hydrogen ion source in National Institute for Fusion Science. H{sub α} reduction indicates a reduction of negative hydrogen ions because the mutual neutralization process between H{sup +} and H{sup −} ions causes the dominant excitation process for H{sub α} emission in the rich H{sup −} condition such as in ionic plasma. We observed a significant change in H{sub α} reduction distribution due to change in the bias voltage, which is used to suppress the electron influx. Small H{sub α} reduction in higher bias is likely because the production of negative ions is suppressed by the potential difference between the plasma and PG surface.

  8. On Transients in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.

    2011-01-01

    In detached Bridgman growth, a gap exists between the growing crystal and the crucible wall. According to crystal shape stability theory, only specific gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. The transient shapes are calculated assuming that the growth angle is constant. Anisotropy and dynamic contact angle effects are considered. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. However, heat transfer will influence the crystal-melt interface shape. The local angles and the crystal-melt-vapor triple junction are analyzed and the applicability of the Herring formula is discussed. A potential microgravity experiment is proposed which would enhance our understanding of the detached growth dynamic stability problem.

  9. COLUMBIC OXIDE ADSORPTION PROCESS FOR SEPARATING URANIUM AND PLUTONIUM IONS

    DOEpatents

    Beaton, R.H.

    1959-07-14

    A process is described for separating plutonium ions from a solution of neutron irradiated uranium in which columbic oxide is used as an adsorbert. According to the invention the plutonium ion is selectively adsorbed by Passing a solution containing the plutonium in a valence state not higher than 4 through a porous bed or column of granules of hydrated columbic oxide. The adsorbed plutonium is then desorbed by elution with 3 N nitric acid.

  10. Detached Growth of Germanium and Germaniumsilicon

    NASA Technical Reports Server (NTRS)

    Dold, P.; Schweizer, M.; Szofran, F.; Benz, K. W.

    1999-01-01

    Up to now, detached growth was observed mainly under microgravity, i.e. under the absence of hydrostatic pressure that hinders the formation of a free melt meniscus. the detached growth of germanium doped with gallium was obtained under 1 g conditions, the growth was performed in quartz-glass ampoule. Part of the crystal grew without wall contact, the detached growth was observed in-situ with a CCD-camera as well as after the growth process in form of growth lines and the formation of <111> facets on the crystal surface. GeSi crystal (oriientation: <111>, maximum silicon content: 4 at%, seed material: Ge) was grown in a pBN crucible (excluding the possibility of in-situ monitoring of the growth process). The grown crystal exhibits three growth facets, indicating also wall free growth. Surface analysis of the crystals (NDIC, SEM) and characterization of crystal segregation (EDAX, resistivity measurement) and defect structure (EPD, x-ray diffraction measurements) will be presented.

  11. Gelling process of sodium alginate with bivalent ions rich microsphere: Nature of bivalent ions

    NASA Astrophysics Data System (ADS)

    Mauri, Marco; Vicini, Silvia; Castellano, Maila

    2016-05-01

    In the paper we present a new approach for obtaining a controlled gelling process of sodium alginate, based on the quantity of bivalent ions rich alginate micro-beads added as crosslinkers. Typically, calcium ions are used in gelation of alginate solutions. In this study we present different gelling systems realized with alginate microspheres, made by electrospinning methodology, enriched with different bivalent ions (Ca2+, Ba2+ and Mg2+). The microspheres were characterized under the point of view of the morphology by OM and as the ions content. Realized gels were characterized in light of the amount of the ions added to the alginate solution, and in light of the different dimensions of the micro-beads, using rheological measurements to assess the variation in the storage modulus (G'), loss modulus (G″) and complex viscosity (η*).

  12. Silicon solar cells by ion implantation and pulsed energy processing

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, A. R.; Minnucci, J. A.; Shaughnessy, T. S.; Greenwald, A. C.

    1976-01-01

    A new method for fabrication of silicon solar cells is being developed around ion implantation in conjunction with pulsed electron beam techniques to replace conventional furnace processing. Solar cells can be fabricated totally in a vacuum environment at room temperature. Cells with 10% AM0 efficiency have been demonstrated. High efficiency cells and effective automated processing capabilities are anticipated.

  13. Experimental study of single-electron detachment for Cu{sup −}, Ag{sup −}, Au{sup −}, Co{sup −}, and Ir{sup −} in collisions with Kr and Xe

    SciTech Connect

    Ye, Jingru; Zhao, Zilong; Zhu, Yiyang; Li, Junqin; Zhang, Xuemei

    2014-09-15

    The single electron detachment (SED) cross sections for Cu{sup −}, Ag{sup −}, Au{sup −}, Co{sup −}, and Ir{sup −} in collisions with Kr and Xe in the energy range of 10keV≤E≤30keV are measured by using the growth rate method in our experiments. The SED cross sections increase as the incident velocity increases. These data are compared with other available experimental data for the corresponding negative ions colliding with Ar. The affinities of the negative ions and the mass relation between the projectile and the target seem important in the electron detachment process.

  14. Defect production and recombination during low-energy ion processing

    SciTech Connect

    Kellerman, B.K.; Floro, J.A.; Chason, E.; Brice, D.K.; Picraux, S.T.; White, J.M.

    1994-10-01

    Low-energy ion processing produces damaged, microroughened semiconductor surfaces due to the production of point defects. The authors present a study of point defect production and annealing on the Ge(001)-2x1 surface during low-energy inert ion bombardment as a function of ion energy, ion mass and substrate temperature. Ion-induced surface point defect production was quantified experimentally in real time using in situ Reflection High Energy Electron Diffraction. The observed surface defect yield decreased abruptly around room temperature as the substrate temperature was increased from 175 K to 475 K. The authors have developed Monte Carlo simulations of defect diffusion to model defect recombination both in the bulk and on the surface. Bulk defect production statistics generated by a binary collision simulator, TRIMRC, were coupled with our bulk diffusion simulator to predict the number of ion-induced surface defects. A comparison between the experimental results and the simulation predictions indicated that defects produced in the bulk may represent a significant contribution to the observed surface defect yield and suggested that TRIMRC may overestimate the depth distribution of the defects. The simulations further indicated that the abrupt drop in the experimental yield with increasing substrate temperature does not arise from bulk defect recombination. The Monte Carlo simulations of surface diffusion (applicable to any crystalline surface) support a defect annealing mechanism (at low ion fluxes) that involves surface recombination of defects generated within a single cascade.

  15. A closed loop process for recycling spent lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Gratz, Eric; Sa, Qina; Apelian, Diran; Wang, Yan

    2014-09-01

    As lithium ion (Li-ion) batteries continue to increase their market share, recycling Li-ion batteries will become mandatory due to limited resources. We have previously demonstrated a new low temperature methodology to separate and synthesize cathode materials from mixed cathode materials. In this study we take used Li-ion batteries from a recycling source and recover active cathode materials, copper, steel, etc. To accomplish this the batteries are shredded and processed to separate the steel, copper and cathode materials; the cathode materials are then leached into solution; the concentrations of nickel, manganese and cobalt ions are adjusted so NixMnyCoz(OH)2 is precipitated. The precipitated product can then be reacted with lithium carbonate to form LiNixMnyCozO2. The results show that the developed recycling process is practical with high recovery efficiencies (∼90%), and 1 ton of Li-ion batteries has the potential to generate 5013 profit margin based on materials balance.

  16. Elementary processes during collisions of ions with tryptophan molecules

    NASA Astrophysics Data System (ADS)

    Afrosimov, V. V.; Basalaev, A. A.; Kuz'michev, V. V.; Panov, M. N.; Smirnov, O. V.

    2016-03-01

    The relative cross sections of elementary processes occurring in single collisions of tryptophan molecules in the gaseous phase with He2+ ions with energy 4 keV/u are measured using time-of-flight mass spectrometry for studying the mechanism of radiation damage of amino acid molecules. The fragmentation channels for intermediate singly and doubly charged tryptophan molecular ions formed during one-electron capture, two-electron capture, and electron capture with ionization are investigated. Significant difference is observed in the mass spectra of fragmentation of intermediate doubly charged ions formed during the capture with ionization and double capture, which is associated with different energies of excitation of {C11H12N2O2}2+* ions.

  17. Analytic formulas for above threshold ionization or detachment plateau spectra

    NASA Astrophysics Data System (ADS)

    Frolov, M. V.; Manakov, N. L.; Starace, Anthony F.

    2009-11-01

    Closed form analytic formulas are derived in the tunneling limit for both above threshold detachment (ATD) of negative ions and above threshold ionization (ATI) of neutral atoms. These formulas provide a fully quantum justification of the well-known classical three-step scenario for strong field ionization and detachment spectra in the high energy region of the ATI or ATD plateau and also provide analytical insight into how the ATI/ATD rates may be controlled by varying the laser field parameters or by varying the atomic species.

  18. On Favorable Thermal Fields for Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Stelian, Carmen; Volz, Martin P.; Derby, Jeffrey J.

    2009-01-01

    The thermal fields of two Bridgman-like configurations, representative of real systems used in prior experiments for the detached growth of CdTe and Ge crystals, are studied. These detailed heat transfer computations are performed using the CrysMAS code and expand upon our previous analyses [14] that posited a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. Computational results indicate that heat transfer conditions that led to successful detached growth in both of these systems are in accordance with our prior assertion, namely that the prevention of crystal reattachment to the crucible wall requires the avoidance of any undercooling of the melt meniscus during the growth run. Significantly, relatively simple process modifications that promote favorable thermal conditions for detached growth may overcome detrimental factors associated with meniscus shape and crucible wetting. Thus, these ideas may be important to advance the practice of detached growth for many materials.

  19. High and Low Temperature Oceanic Detachment Faults

    NASA Astrophysics Data System (ADS)

    Titarenko, Sofya; McCaig, Andrew

    2013-04-01

    One of the most important discoveries in Plate Tectonics in the last ten years is a "detachment mode" of seafloor spreading. Up to 50% of the Atlantic seafloor has formed by a combination of magmatism and slip on long-lived, convex-up detachment faults, forming oceanic core complexes (OCC). Two end-member types of OCC can be defined: The Atlantis Bank on the Southwest Indian Ridge is a high temperature OCC sampled by ODP Hole 735b. Deformation was dominated by crystal-plastic flow both above and below the solidus at 800-950 °C, over a period of around 200 ka. In contrast, the Atlantis Massif at 30 °N in the Atlantic, sampled by IODP Hole 1309D, is a low temperature OCC in which crystal plastic deformation of gabbro is very rare and greenschist facies deformation was localised onto talc-tremolite-chlorite schists in serpentinite, and breccia zones in gabbro and diabase. The upper 100m of Hole 1309D contains about 43% diabase intruded into hydrated fault breccias. This detachment fault zone can be interpreted as a dyke-gabbro transition, which was originally (before flexural unroofing) a lateral boundary between active hydrothermal circulation in the fault zone and hangingwall, and intrusion of gabbroic magma in the footwall. Thus a major difference between high and low temperature detachment faults may be cooling of the latter by active hydrothermal circulation. 2-D thermal modelling suggests that if a detachment fault is formed in a magmatically robust segment of a slow spreading ridge, high temperature mylonites can be formed for 1-2 ka provided there is no significant hydrothermal cooling of the fault zone. In contrast, if the fault zone is held at temperatures of 400 °C by fluid circulation, cooling of the upper 1 km of the fault footwall occurs far too rapidly for extensive mylonites to form. Our models are consistent with published cooling rate data from geospeedometry and isotopic closure temperatures. The control on this process is likely a combination of

  20. Process for recovering pertechnetate ions from an aqueous solution also containing other ions

    DOEpatents

    Rogers, Robin; Horwitz, E. Philip; Bond, Andrew H.

    1997-01-01

    A solid/liquid process for the separation and recovery of TcO.sub.4.sup.-1 ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO.sub.4.sup.-1 ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO.sub.4.sup.-1 ions in such an aqueous solution that is free from MoO.sub.4.sup.-2 ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture.

  1. Process for recovering pertechnetate ions from an aqueous solution also containing other ions

    DOEpatents

    Rogers, R.; Horwitz, E.P.; Bond, A.H.

    1997-02-18

    A solid/liquid process for the separation and recovery of TcO{sub 4}{sup {minus}1} ions from an aqueous solution is disclosed. The solid support comprises separation particles having surface-bonded poly(ethylene glycol) groups; whereas the aqueous solution from which the TcO{sub 4}{sup {minus}1} ions are separated contains a poly(ethylene glycol) liquid/liquid biphase-forming amount of a dissolved salt. A solid/liquid phase admixture of separation particles containing bound TcO{sub 4}{sup {minus}1} ions in such an aqueous solution that is free from MoO{sub 4}{sup {minus}2} ions is also contemplated, as is a chromatography apparatus containing that solid/liquid phase admixture. 15 figs.

  2. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    SciTech Connect

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

  3. Arbitrary waveform generator for quantum information processing with trapped ions

    NASA Astrophysics Data System (ADS)

    Bowler, R.; Warring, U.; Britton, J. W.; Sawyer, B. C.; Amini, J.

    2013-03-01

    Atomic ions confined in multi-electrode traps have been proposed as a basis for scalable quantum information processing. This scheme involves transporting ions between spatially distinct locations by use of time-varying electric potentials combined with laser or microwave pulses for quantum logic in specific locations. We report the development of a fast multi-channel arbitrary waveform generator for applying the time-varying electric potentials used for transport and for shaping quantum logic pulses. The generator is based on a field-programmable gate array controlled ensemble of 16-bit digital-to-analog converters with an update frequency of 50 MHz and an output range of ±10 V. The update rate of the waveform generator is much faster than relevant motional frequencies of the confined ions in our experiments, allowing diabatic control of the ion motion. Numerous pre-loaded sets of time-varying voltages can be selected with 40 ns latency conditioned on real-time signals. Here we describe the device and demonstrate some of its uses in ion-based quantum information experiments, including speed-up of ion transport and the shaping of laser and microwave pulses.

  4. The mechanics of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2013-03-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular, and retinal pigment epithelium (RPE) pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed tissue within which e.g., the hydraulic conductivities of the retina or choroid increase, the RPE pumps fail, or the adhesion properties change. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. This work supported by the Army Research Office through grant 58386MA

  5. Size distribution of detached drops

    NASA Astrophysics Data System (ADS)

    Baluev, V. V.; Stepanov, V. M.

    1989-10-01

    The law governing the size distribution of detached gas-liquid streams of drops has been determined analytically, and a comparison is carried out against experimental data existing in the literature. The derived theoretical relationships offer an excellent description of existing experimental results.

  6. SOLPS5.1 analysis of detachment with drifts and gas pumping effects in EAST

    NASA Astrophysics Data System (ADS)

    Du, Hailong; Sang, Chaofeng; Wang, Liang; Bonnin, Xavier; Guo, Houyang; Sun, Jizhong; Wang, Dezhen

    2016-08-01

    The aim of this paper is to estimate the effects of usual drifts and gas puffing/pumping locations on divertor detachment and Ar ion transport in the Experimental Advanced Superconducting Tokamak (EAST) by using the edge plasma code package SOLPS5.1. The simulated results reveal that which target plate first detaches depends strongly on the usual drifts, but not on the location of impurity gas puffing, which could be one of the possible explanations for the experimentally observed phenomenon (Chen et al 2013 Phys. Plasmas 20 022311) that the lower inner target first detached compared to the lower outer target with the lower outer gas puffing. The physics behind this phenomenon is that drifts not only can induce background ion flux, plasma density and temperature redistribution in the scrape-off layer (SOL) and divertor region, but also can change the Ar impurity force balance leading to Ar ions being dragged from bottom to top. Furthermore, the simulated results illustrate that the Ar ion transport in the SOL and divertor region is similar for different gas puffing locations including upstream and divertor region before partial detachment. However, the Ar ions penetrate into the core more easily, giving rise to more discharge disruption during complete detachment with upstream gas puffing than with divertor region puffing. Finally, we also estimate the effect of gas pumping on the detachment in order to realize long-pulse partial detachment in EAST. The results indicate that long-pulse partial detachment could be obtained by improving the pumping speed to match the puffing speed in case the excess Ar atoms accumulate in the core plasma during partial detachment in EAST.

  7. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M. P.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al.

  8. Detached growth of germanium by directional solidification

    NASA Astrophysics Data System (ADS)

    Palosz, W.; Volz, M. P.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2005-04-01

    The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al.

  9. Process for modifying the metal ion sorption capacity of a medium

    DOEpatents

    Lundquist, Susan H.

    2002-01-01

    A process for modifying a medium is disclosed that includes treating a medium having a metal ion sorption capacity with a solution that includes: A) an agent capable of forming a complex with metal ions; and B) ions selected from the group consisting of sodium ions, potassium ions, magnesium ions, and combinations thereof, to create a medium having an increased capacity to sorb metal ions relative to the untreated medium.

  10. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Paul Mattione

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  11. A Scalable Microfabricated Ion Trap for Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Maunz, Peter; Haltli, Raymond; Hollowell, Andrew; Lobser, Daniel; Mizrahi, Jonathan; Rembetski, John; Resnick, Paul; Sterk, Jonathan D.; Stick, Daniel L.; Blain, Matthew G.

    2016-05-01

    Trapped Ion Quantum Information Processing (QIP) relies on complex microfabricated trap structures to enable scaling of the number of quantum bits. Building on previous demonstrations of surface-electrode ion traps, we have designed and characterized the Sandia high-optical-access (HOA-2) microfabricated ion trap. This trap features high optical access, high trap frequencies, low heating rates, and negligible charging of dielectric trap components. We have observed trap lifetimes of more than 100h, measured trap heating rates for ytterbium of less than 40quanta/s, and demonstrated shuttling of ions from a slotted to an above surface region and through a Y-junction. Furthermore, we summarize demonstrations of high-fidelity single and two-qubit gates realized in this trap. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000. This work was supported by the Intelligence Advanced Research Projects Activity (IARPA).

  12. Production of distributed phase plates using an energetic ion process

    NASA Astrophysics Data System (ADS)

    Smith, Douglas J.; Warner, Joy A.; LeBarron, Nelson E.; LaDelia, Salvatore

    1999-04-01

    Laser-driven implosion experiments require optical phase conversion to create a uniformly irradiated target. Distributed phase plates provide a quasi-random phase front that aids in beam smoothing on the target; however, the DPP must survive the high fluences of the tripled OMEGA beam at 351 nm. The continuous DPP produces higher efficiency and less risk of damage to opposing optics than the previous binary design. DPPs are created by exposing a gray scale pattern in photoresist and then etching the pattern in to silica. Several problems were solved during the development stage of ion etching DPPs. The etch uniformity was limited to less than 6 percent across a 28-cm clear aperture by modeling the 16-cm ion source and erosion characteristics of the photoresist and silica. Surface texturing was linked to overheating of the photoresist by the ion source and was solved by radiant cooling. Near-field defects capable of focusing damage in levels of fluence on downstream optics were created in the photoresist exposure process and were removed after etching. The damage thresholds of the silica surface generally increase after etching is fare is taken to avoid re-sputtering of tooling onto the optics surface. Sixty ion-etched DPPs were installed in December 1997 and, currently, damage has not been observed on the optics.

  13. Subduction and slab detachment in the Mediterranean-Carpathian region.

    PubMed

    Wortel, M J; Spakman, W

    2000-12-01

    Seismic tomography models of the three-dimensional upper mantle velocity structure of the Mediterranean-Carpathian region provide a better understanding of the lithospheric processes governing its geodynamical evolution. Slab detachment, in particular lateral migration of this process along the plate boundary, is a key element in the lithospheric dynamics of the region during the last 20 to 30 million years. It strongly affects arc and trench migration, and causes along-strike variations in vertical motions, stress fields, and magmatism. In a terminal-stage subduction zone, involving collision and suturing, slab detachment is the natural last stage in the gravitational settling of subducted lithosphere. PMID:11110653

  14. Adhesion and detachment of a capsule in axisymmetric flow

    NASA Astrophysics Data System (ADS)

    Keh, M. P.; Leal, L. G.

    2016-05-01

    The adhesion and detachment of a capsule on a solid boundary surface is studied via a combination of scaling theory and numerical simulation and the behavior is compared and contrasted with a vesicle. It is shown that the dominant physical property for both capsules and vesicles is the area dilation modulus Ks of the membrane. The nonzero shear modulus Gs for capsules increases the resistance to deformation and thus decreases slightly the equilibrium contact radius for an adhered capsule compared to an adhered vesicle. The detachment process in this study is due to an external axisymmetric flow. Unlike a rigid body that must be pulled away without change of shape, capsules (and vesicles) almost always detach dominantly by peeling in which the contact radius decreases but the minimum separation distance does not change until the final moments of detachment. Compared to a vesicle with the same Ks, a capsule maintains a more compact shape and is harder to elongate under a given external flow. Hence, the detachment process is slower for capsules compared to vesicles with the same Ks.

  15. Detached tip of a transseptal sheath during left atrial ablation.

    PubMed

    El-Damaty, Ahmed; Love, Michael; Parkash, Ratika

    2012-02-15

    Left atrial ablation has become more commonplace with the advent of catheter ablation for atrial fibrillation. A number of transseptal sheaths have been produced to enhance safe and efficient catheter manipulation in the left atrium (LA) for these procedures. Some of the sheaths have been subject to recall due to partial or complete detachment of its radiopaque tip. We report a case of a 46 year-old female diagnosed with idiopathic dilated cardiomyopathy that presented with atypical left atrial flutter. During electrophysiologic study, a Swartz braided SL1 (SL-1) transseptal sheath was used to introduce the ablation catheter to the left atrium. During left atrial mapping, the radiopaque tip of the sheath detached from the rest of the sheath and was seen floating in the LA. After exchanging the SL-1 sheath with a deflectable sheath, the detached segment was retrieved out of the LA and eventually out of the vascular system using an angioplasty balloon advanced over a wire and inflated distal to the lumen of the detached tip. The root cause of this malfunction was found to be lack of a secondary bonding process that these sheaths generally undergo during the manufacturing process. We describe the case of a left atrial ablation procedure where a novel percutaneous method was able to successfully retrieve the detached tip of a transseptal sheath from the vascular system, thereby avoiding a potential catastrophic complication or thoracotomy. This method may be useful in other cases where similar circumstances may present. PMID:22162088

  16. Cbl-b promotes cell detachment via ubiquitination of focal adhesion kinase

    PubMed Central

    Fan, Yibo; Qu, Xiujuan; Ma, Yanju; Liu, Yunpeng; Hu, Xuejun

    2016-01-01

    Cancer cell detachment from the primary tumor site represents the first stage of metastasis. Previous studies have identified that cell detachment is triggered by cytoskeletal disruption, which may induce a wide variety of cellular changes. Focal adhesion kinase (FAK) exhibits crucial cellular functions, including regulation of the cytoskeleton. These observations have provided exciting insights into the effect of FAK in cell detachment; however, the involvement of FAK in cell detachment remains controversial. The aim of the present study was to evaluate the effect of FAK and its function in the process of cell detachment. The results revealed that FAK expression was downregulated following trypsin treatment in human gastric, lung, colon and breast cancer cell lines, as well as a human gastric epithelial cell line. Knockdown of FAK enhanced cell detachment in gastric cancer MGC803 cells, indicating that FAK inhibits cell detachment. Further investigation revealed that trypsin induced monoubiquitination of FAK. In addition, the lysosome inhibitor, NH4Cl, decreased trypsin-induced degradation of FAK. Casitas B-lineage lymphoma-b (Cbl-b), an E3 ubiquitin ligase, was involved in this process, which interacted with FAK, as demonstrated by co-precipitation experiments, and promoted trypsin-induced ubiquitin-lysosome degradation of FAK. These results indicate that Cbl-b promotes cell detachment via ubiquitination of FAK. These findings provide novel insights regarding the effect of FAK and Cbl-b in the process of cancer cell detachment.

  17. Growth and Detachment of Cell Clusters from Mature Mixed-Species Biofilms

    PubMed Central

    Stoodley, Paul; Wilson, Suzanne; Hall-Stoodley, Luanne; Boyle, John D.; Lappin-Scott, Hilary M.; Costerton, J. W.

    2001-01-01

    Detachment from biofilms is an important consideration in the dissemination of infection and the contamination of industrial systems but is the least-studied biofilm process. By using digital time-lapse microscopy and biofilm flow cells, we visualized localized growth and detachment of discrete cell clusters in mature mixed-species biofilms growing under steady conditions in turbulent flow in situ. The detaching biomass ranged from single cells to an aggregate with a diameter of approximately 500 μm. Direct evidence of local cell cluster detachment from the biofilms was supported by microscopic examination of filtered effluent. Single cells and small clusters detached more frequently, but larger aggregates contained a disproportionately high fraction of total detached biomass. These results have significance in the establishment of an infectious dose and public health risk assessment. PMID:11722913

  18. Nano-scale processes behind ion-beam cancer therapy

    NASA Astrophysics Data System (ADS)

    Surdutovich, Eugene; Garcia, Gustavo; Mason, Nigel; Solov'yov, Andrey V.

    2016-04-01

    This topical issue collates a series of papers based on new data reported at the third Nano-IBCT Conference of the COST Action MP1002: Nanoscale Insights into Ion Beam Cancer Therapy, held in Boppard, Germany, from October 27th to October 31st, 2014. The Nano-IBCT COST Action was launched in December 2010 and brought together more than 300 experts from different disciplines (physics, chemistry, biology) with specialists in radiation damage of biological matter from hadron-therapy centres, and medical institutions. This meeting followed the first and the second conferences of the Action held in October 2011 in Caen, France and in May 2013 in Sopot, Poland respectively. This conference series provided a focus for the European research community and has highlighted the pioneering research into the fundamental processes underpinning ion beam cancer therapy. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Gustavo Garcia and Eugene Surdutovich.

  19. ION EXCHANGE PROCESS FOR THE RECOVERY AND PURIFICATION OF MATERIALS

    DOEpatents

    Long, R.S.; Bailes, R.H.

    1958-04-15

    A process for the recovery of certain metallic ions from aqueous solutions by ion exchange techniques is described. It is applicable to elements such as vanadium, chromium, nnanganese, and the like, which are capable of forming lower valent cations soluble in aqueous solutions and which also form ldgher valent anions soluble in aqueous acidic solutions. For example, small amounts of vanadium occurring in phosphoric acid prepared from phosphate rock may be recovered by reducing the vanadium to a trivalent cation adsorbing; the vanadium in a cationic exchange resin, then treating the resin with a suitable oxidizing agent to convert the adsorbed vanadium to a higher valent state, and finally eluting; the vanadium as an anion from the resin by means of an aqueous acidic solution.

  20. Entanglement and Quantum Information Processing with Trapped Ions*

    NASA Astrophysics Data System (ADS)

    Chiaverini, John

    2004-05-01

    Atomic ions confined in radio frequency traps, cooled and addressed with laser pulses, constitute a scalable system for bringing about and exploring quantum entanglement and information processing. Along with relatively high entangling-gate and single-qubit-rotation fidelities, long coherence times enable the execution of some basic quantum algorithms and communication protocols. At NIST we use a multi-zone trap in which entanglement can be distributed over the zones through the spatial separation and combination of several entangled ion qubits, each of which can be separately measured. Current experiments include superdense coding, quantum teleportation, entanglement-enhanced quantum state detection, and entangled state spectroscopy. These experiments and those from other groups will be summarized. *This work was supported by ARDA/NSA and NIST, and done in collaboration with T. Schaetz, M. Barrett, D. Leibfried, J. Britton, W. Itano, J. Jost, C. Langer, R. Ozeri, T. Rosenband, and D. J. Wineland.

  1. Ageing dynamics of ion bombardment induced self-organization processes

    PubMed Central

    Bikondoa, Oier; Carbone, Dina; Chamard, Virginie; Metzger, Till Hartmut

    2013-01-01

    Instabilities caused during the erosion of a surface by an ion beam can lead to the formation of self-organized patterns of nanostructures. Understanding the self-organization process requires not only the in-situ characterization of ensemble averaged properties but also probing the dynamics. This can be done with the use of coherent X-rays and analyzing the temporal correlations of the scattered intensity. Here, we show that the dynamics of a semiconductor surface nanopatterned by normal incidence ion beam sputtering are age-dependent and slow down with sputtering time. This work provides a novel insight into the erosion dynamics and opens new perspectives for the understanding of self-organization mechanisms. PMID:23685386

  2. Mechanical and tribological properties of ion beam-processed surfaces

    SciTech Connect

    Kodali, P.

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness.

  3. Enzymatic Detachment of Therapeutic Mesenchymal Stromal Cells Grown on Glass Carriers in a Bioreactor

    PubMed Central

    Salzig, Denise; Schmiermund, Alexandra; P. Grace, Pablo; Elseberg, Christiane; Weber, Christian; Czermak, Peter

    2013-01-01

    Cell therapies require the in vitro expansion of adherent cells such as mesenchymal stromal cells (hMSCs) in bioreactor systems or other culture environments, followed by cell harvest. As hMSCs are strictly adherent cells, cell harvest requires cell detachment. The use of hMSCs for cell therapy requires GMP production in accordance with the guidelines for advanced therapeutic medical products. Therefore, several GMP-conform available proteolytic enzymes were investigated for their ability to promote hMSC detachment. An allogeneic hMSC cell line (hMSC-TERT) that is used in clinical trials in the form of alginate cell capsules was chosen as a model. This study investigated the influence of several factors on the outcome of proteolytic hMSC-TERT detachment. Therefore, hMSC-TERT detachment was analyzed in different cultivation systems (static, dynamic) and in combination with further cell processing including encapsulation. Only two of the commercially available enzymes (AccutaseTM, TrypZeanTM) that fulfill all process requirements (commercial availability, cost, GMP conditions during manufacturing and non-animal origin) are found to be generally suitable for detaching hMSC-TERT. Combining cell detachment with encapsulation demonstrated a high impact of the experimental set up on cell damage. It was preferable to reduce the temperature during detachment and limit the detachment time to a maximum of 20 minutes. Cell detachment in static systems was not comparable with detachment in dynamic systems. Detachment yields in dynamic systems were lower and cell damage was higher for the same experimental conditions. Finally, only TrypZeanTM seemed to be suitable for the detachment of hMSC-TERT from dynamic reactor systems. PMID:24478807

  4. Numerical Investigation of Plasma Detachment in Magnetic Nozzle Experiments

    NASA Technical Reports Server (NTRS)

    Sankaran, Kamesh; Polzin, Kurt A.

    2008-01-01

    At present there exists no generally accepted theoretical model that provides a consistent physical explanation of plasma detachment from an externally-imposed magnetic nozzle. To make progress towards that end, simulation of plasma flow in the magnetic nozzle of an arcjet experiment is performed using a multidimensional numerical simulation tool that includes theoretical models of the various dispersive and dissipative processes present in the plasma. This is an extension of the simulation tool employed in previous work by Sankaran et al. The aim is to compare the computational results with various proposed magnetic nozzle detachment theories to develop an understanding of the physical mechanisms that cause detachment. An applied magnetic field topology is obtained using a magnetostatic field solver (see Fig. I), and this field is superimposed on the time-dependent magnetic field induced in the plasma to provide a self-consistent field description. The applied magnetic field and model geometry match those found in experiments by Kuriki and Okada. This geometry is modeled because there is a substantial amount of experimental data that can be compared to the computational results, allowing for validation of the model. In addition, comparison of the simulation results with the experimentally obtained plasma parameters will provide insight into the mechanisms that lead to plasma detachment, revealing how they scale with different input parameters. Further studies will focus on modeling literature experiments both for the purpose of additional code validation and to extract physical insight regarding the mechanisms driving detachment.

  5. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described.

  6. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described

  7. Ion Sponge: A 3-Dimentional Array of Quadrupole Ion Traps for Trapping and Mass-Selectively Processing Ions in Gas Phase

    PubMed Central

    2015-01-01

    In this study, the concept of ion sponge has been explored for developing 3D arrays of large numbers of ion traps but with simple configurations. An ion sponge device with 484 trapping units in a volume of 10 × 10 × 3.2 cm has been constructed by simply stacking 9 meshes together. A single rf was used for trapping ions and mass-selective ion processing. The ion sponge provides a large trapping capacity and is highly transparent for transfer of ions, neutrals, and photons for gas phase ion processing. Multiple layers of quadrupole ion traps, with 121 trapping units in each layer, can operate as a single device for MS or MS/MS analysis, or as a series of mass-selective trapping devices with interlayer ion transfers facilitated by AC and DC voltages. Automatic sorting of ions to different trapping layers based on their mass-to-charge (m/z) ratios was achieved with traps of different sizes. Tandem-in-space MS/MS has also been demonstrated with precursor ions and fragment ions trapped in separate locations. PMID:24758328

  8. Electron cyclotron resonance microwave ion sources for thin film processing

    SciTech Connect

    Berry, L.A.; Gorbatkin, S.M.

    1990-01-01

    Plasmas created by microwave absorption at the electron cyclotron resonance (ECR) are increasingly used for a variety of plasma processes, including both etching and deposition. ECR sources efficiently couple energy to electrons and use magnetic confinement to maximize the probability of an electron creating an ion or free radical in pressure regimes where the mean free path for ionization is comparable to the ECR source dimensions. The general operating principles of ECR sources are discussed with special emphasis on their use for thin film etching. Data on source performance during Cl base etching of Si using an ECR system are presented. 32 refs., 5 figs.

  9. Prospects for reducing the processing cost of lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Wood, David L.; Li, Jianlin; Daniel, Claus

    2015-02-01

    A detailed processing cost breakdown is given for lithium-ion battery (LIB) electrodes, which focuses on: 1) elimination of toxic, costly N-methylpyrrolidone (NMP) dispersion chemistry; 2) doubling the thicknesses of the anode and cathode to raise energy density; and 3) reduction of the anode electrolyte wetting and SEI-layer formation time. These processing cost reduction technologies generically adaptable to any anode or cathode cell chemistry and are being implemented at ORNL. This paper shows step by step how these cost savings can be realized in existing or new LIB manufacturing plants using a baseline case of thin (power) electrodes produced with NMP processing and a standard 10-14-day wetting and formation process. In particular, it is shown that aqueous electrode processing can cut the electrode processing cost and energy consumption by an order of magnitude. Doubling the thickness of the electrodes allows for using half of the inactive current collectors and separators, contributing even further to the processing cost savings. Finally wetting and SEI-layer formation cost savings are discussed in the context of a protocol with significantly reduced time. These three benefits collectively offer the possibility of reducing LIB pack cost from 502.8 kW h-1-usable to 370.3 kW h-1-usable, a savings of 132.5/kWh (or 26.4%).

  10. Soil detachment by overland flow under different vegetation restoration models in the loess plateau of China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land use change has significant effects on soil properties and vegetation cover and thus probably affects soil detachment by overland flow. Few studies were conducted to evaluate the effect of restoration models on the soil detachment process in the Loess Plateau in the past decade during which a Gr...

  11. Online process control of acidic texturisation baths with ion chromatography.

    PubMed

    Zimmer, Martin; Oltersdorf, Antje; Rentsch, Jochen

    2009-12-15

    Etching of silicon with mixtures of hydrofluoric acid and nitric acid is a widely used process in silicon solar cell fabrication. One precondition for an optimized usage of the acidic etching baths is the exact knowledge of the chemical bath composition. In this paper, we investigated a fast and online-capable method for the total analysis of all bath constituents by ion chromatography. The chromatographical system consists of a low-volume injection valve, which injects the concentrated samples directly into the KOH-based eluent. After separation and detection of nitrate and fluoride, a post-column derivatization with sodium molybdate is applied to detect the hexafluorosilicic acid, which enriches in the texturisation bath during the etching process. The results of the presented approach are discussed and compared with already published chromatographical and titration methods found in literature. PMID:19836511

  12. Bacterial detachment from salivary conditioning films by dentifrice supernates.

    PubMed

    van der Mei, Henny C; White, Donald J; Cox, Ed R; Geertsema-Doornbusch, Gesinda I; Busscher, Henk J

    2002-01-01

    This study compared the detachment by supernates of nine different dentifrices of four oral bacterial strains adhering to a salivary pellicle in a parallel plate flow chamber. Ultra-thin bovine enamel slabs were coated for 1.5 h with human whole saliva. Following buffer rinsing, a bacterial suspension of Streptococcus oralis, Streptococcus sanguis, Streptococcus mutans or Actinomyces naeslundii was perfused through the flow chamber at a shear rate of 30 s-1 for four hours, and the number of adhering bacteria n4h was enumerated by image analysis after buffer rinsing at the same shear rate. Then, a 25 wt%-dentifrice/water supernate was perfused through the flow chamber for four minutes, followed by eight minutes of buffer rinsing and another enumeration of the number of bacteria that had remained adhering nad. Finally, an air-bubble was passed through the flow chamber to mimic the occasionally high detachment forces occurring in the oral cavity, and the adhering bacteria nab were counted again. On average, S. sanguis was the easiest to detach (73% averaged over all dentifrice supernates), while A. naeslundii was the most difficult (22% on average). The combined detachment of bacteria by dentifrice supernates and air-bubble ranged from a low of 16% to a high of 80%. Dentifrices containing pyrophosphate and polymeric polyphosphate (hexametaphosphate) surface active ingredients appeared to produce the most consistent and strongest desorption effects on plaque bacteria. Factors apparently important to bacterial detachment from pellicle-covered tooth surfaces by dentifrice formulations include the nature of adhesion of bacterial strains and chemical composition of the dentifrice formulations, including pH, surfactant system and the effect of added ingredients (dispersants, metal ions, peroxides, baking soda). PMID:11507932

  13. Observations of energetic water-group ions at Comet Giacobini-Zinner - Implications for ion acceleration processes

    NASA Astrophysics Data System (ADS)

    Richardson, I. G.; Cowley, S. W. H.; Hynds, R. J.; Tranquille, C.; Sanderson, T. R.; Wenzel, K.-P.

    1987-10-01

    Observations of energetic water-group pick-up ions made by the EPAS instrument during ICE fly-by of Comet P/Giacobini-Zinner are investigated for evidence concerning the processes which accelerate the ions from initial pick-up energies of around 10 keV to energies of a few hundred keV. The form of the ion spectrum in the ion rest frame is investigated and compared with theoretical suggestions that exponential energy distributions might be produced by either first- or second-order Fermi acceleration in the cometary environment. It is shown that such distributions do not fit the data at all well, but that rather the observed distribution functions closely approximate an exponential in ion speed. The variations of ion intensity and spectral hardness which occur during the comet encounter are investigated, and an indication of the degree of isotropy of the ion distribution in the rest frame of the flow is obtained.

  14. Mechanical and tribological properties of ion beam-processed surfaces

    NASA Astrophysics Data System (ADS)

    Kodali, Padma

    A variety of surface modification and surface coating techniques are currently used in industry to modify the near-surface mechanical properties that influence the friction and wear behavior of metals, metallic alloys, ceramics, and polymers. Near-surface mechanical properties such as hardness and fracture toughness of a coating-substrate system can be tailored economically without changing the bulk properties of the system. The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) Investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation. (2) Characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation. (3) Developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. Wear mechanisms that occurred in implanted and unimplanted surfaces tested against AIS152100

  15. Detached Solidification of Germanium-Silicon Crystals on the ISS

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.; Croell, A.

    2016-01-01

    A series of Ge(sub 1-x) Si(sub x) crystal growth experiments are planned to be conducted in the Low Gradient Furnace (LGF) onboard the International Space Station. The primary objective of the research is to determine the influence of containment on the processing-induced defects and impurity incorporation in germanium-silicon alloy crystals. A comparison will be made between crystals grown by the normal and "detached" Bridgman methods and the ground-based float zone technique. Crystals grown without being in contact with a container have superior quality to otherwise similar crystals grown in direct contact with a container, especially with respect to impurity incorporation, formation of dislocations, and residual stress in crystals. "Detached" or "dewetted" Bridgman growth is similar to regular Bridgman growth in that most of the melt is in contact with the crucible wall, but the crystal is separated from the wall by a small gap, typically of the order of 10-100 microns. Long duration reduced gravity is essential to test the proposed theory of detached growth. Detached growth requires the establishment of a meniscus between the crystal and the ampoule wall. The existence of this meniscus depends on the ratio of the strength of gravity to capillary forces. On Earth, this ratio is large and stable detached growth can only be obtained over limited conditions. Crystals grown detached on the ground exhibited superior structural quality as evidenced by measurements of etch pit density, synchrotron white beam X-ray topography and double axis X-ray diffraction.

  16. Numerical Optimization of the Thermal Field in Bridgman Detached Growth

    NASA Technical Reports Server (NTRS)

    Stelian, C.; Volz, M. P.; Derby, J. J.

    2009-01-01

    The global modeling of the thermal field in two vertical Bridgman-like crystal growth configurations, has been performed to get optimal thermal conditions for a successful detached growth of Ge and CdTe crystals. These computations are performed using the CrysMAS code and expand upon our previous analysis [1] that propose a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. The analysis of the vertical Bridgman configuration with two heaters, used by Palosz et al. for the detached growth of Ge, shows, consistent with their results, that the large wetting angle of germanium on boron nitride surfaces was an important factor to promote a successful detached growth. Our computations predict that by initiating growth much higher into the hot zone of the furnace, the thermal conditions will be favorable for continued detachment even for systems that did not exhibit high contact angles. The computations performed for a vertical gradient freeze configuration with three heaters representative of that used for the detached growth of CdTe, show favorable thermal conditions for dewetting during the entirely growth run described. Improved thermal conditions are also predicted for coated silica crucibles when the solid-liquid interface advances higher into the hot zone during the solidification process. The second set of experiments on CdTe growth described elsewhere has shown the reattachment of the crystal to the crucible after few centimeters of dewetted growth. The thermal modeling of this configuration shows a second solidification front appearing at the top of the sample and approaching the middle line across the third heater. In these conditions, the crystal grows detached from the bottom, but will be attached to the crucible in the upper part because of the solidification without gap in this region. The solidification with two interfaces can be avoided when the top of the sample is positioned below

  17. Espisodic detachment of Martian crustal magnetic fields leading to bulk atmospheric plasma escape

    SciTech Connect

    Brain, D A; Baker, A H; Briggs, J; Eastwood, J P; Halekas, J S; Phan, T

    2009-06-02

    We present an analysis of magnetic field and suprathermal electron measurements from the Mars Global Surveyor (MGS) spacecraft that reveals isolated magnetic structures filled with Martian atmospheric plasma located downstream from strong crustal magnetic fields with respect to the flowing solar wind. The structures are characterized by magnetic field enhancements and rotations characteristic of magnetic flux ropes, and characteristic ionospheric electron energy distributions with angular distributions distinct from surrounding regions. These observations indicate that significant amounts of atmosphere are intermittently being carried away from Mars by a bulk removal process: the top portions of crustal field loops are stretched through interaction with the solar wind and detach via magnetic reconnection. This process occurs frequently and may account for as much as 10% of the total present-day ion escape from Mars.

  18. An experimental investigation of the dissociative ionization process of argon cluster ions induced by electron impact

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Ma, X.; Yan, S.; Xu, S.; Zhang, S.; Zhu, X.; Li, B.; Feng, W.; Qian, D.; Zhang, R.; Guo, D.; Wen, W.; Zhang, D.; Yang, J.; Zhao, D.; Liu, H.

    2014-04-01

    Utilizing the Cold Target Recoil Ions Momentum Spectrometer (COLTRIMS), dissociative ionization of argon cluster was experimentally investigated by electron impact. The recoil ions produced both in the pure ionization process and the dissociative ionization channels are measured with collision energies from 100 and 1000 eV. The ratios of the dimer ions from pure ionization (Ar2P+) and the dimer ions from small cluster dissociation (Ar+2D) to the atomic argon ion (Ar+) in different stagnation pressures were obtained.

  19. IMPACT OF THE SMALL COLUMN ION EXCHANGE PROCESS ON THE DEFENSE WASTE PROCESSING FACILITY - 12112

    SciTech Connect

    Koopman, D.; Lambert, D.; Fox, K.; Stone, M.

    2011-11-07

    The Savannah River Site (SRS) is investigating the deployment of a parallel technology to the Salt Waste Processing Facility (SWPF, presently under construction) to accelerate high activity salt waste processing. The proposed technology combines large waste tank strikes of monosodium titanate (MST) to sorb strontium and actinides with two ion exchange columns packed with crystalline silicotitanate (CST) resin to sorb cesium. The new process was designated Small Column Ion Exchange (SCIX), since the ion exchange columns were sized to fit within a waste storage tank riser. Loaded resins are to be combined with high activity sludge waste and fed to the Defense Waste Processing Facility (DWPF) for incorporation into the current glass waste form. Decontaminated salt solution produced by SCIX will be fed to the SRS Saltstone Facility for on-site immobilization as a grout waste form. Determining the potential impact of SCIX resins on DWPF processing was the basis for this study. Accelerated salt waste treatment is projected to produce a significant savings in the overall life cycle cost of waste treatment at SRS.

  20. Experimental results from detached plasmas in TFTR

    SciTech Connect

    Strachan, J.D.; Boody, F.P.; Bush, C.E.; Cohen, S.A.; Grek, B.; Grisham, L.; Jobes, F.C.; Johnson, D.W.; Mansfield, D.K.; Medley, S.S.

    1986-10-01

    Detached plasmas are formed in TFTR which have the principal property of the boundary to the high temperature plasma core being defined by a radiating layer. This paper documents the properties of TFTR ohmic-detached plasmas with a range of plasma densities at two different plasma currents.

  1. Characterization of Surface Features in Detached Grown GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Cobb, S. D.; Volz, M. P.; Schweizer, M.; Kaiser, N.; Carpenter, P. K.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The growth of detached crystals by the Bridgman technique, in which the growing crystal is not in contact with the crucible wall, has been observed both on earth and in microgravity conditions. At present, the mechanisms contributing to the detachment are not completely understood and until recently detachment has not been reproducibly obtained. It is commonly understood that the main factors that promote the occurrence of detached growth include: high contact angle between the melt and the crucible material, high growth angle, and a pressure difference between the annular gap around the solid below the melt and the volume above the melt along the meniscus. These parameters were varied in Bridgman growth experiments to determine the conditions required to achieve detached growth terrestrially in Ge and GeSi alloys. These experiments are in preparation for experiments on the International Space Station (ISS). The detailed objectives of the flight experiments and a description of the growth methods employed are the subject of another presentation at this Congress. Detached crystals were achieved repeatedly in pyrolytic boron nitride ampoules when a pressure difference was employed. All crystals, except for those grown in fused silica ampoules, were easily removed from their containers; however, this fact alone is not sufficient to infer detached growth. Detachment was verified by comparing profilometer measurements of the radius of the samples with observations of the sample surfaces using optical and electron microscopy. The surfaces of the attached areas of the crystals had the same shape and surface texture as the interior crucible wall. Regions of detached growth contained many unique features and crystal facets could usually be observed. Several of these surface features have been correlated with mechanisms of detachment or free surface growth in general and others to processing events or conditions. These results will be compared with observations of surface

  2. Process for improving moisture resistance of epoxy resins by addition of chromium ions

    NASA Technical Reports Server (NTRS)

    St.clair, A. K.; Stoakley, D. M.; St.clair, T. L.; Singh, J. J. (Inventor)

    1985-01-01

    A process for improving the moisture resistance properties of epoxidized TGMDA and DGEBA resin system by chemically incorporating chromium ions is described. The addition of chromium ions is believed to prevent the absorption of water molecules.

  3. All-ion-implantation process for integrated circuits

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1979-01-01

    Simpler than diffusion fabrication, ion bombardment produces complementary-metal-oxide-semiconductor / silicon-on-sapphire (CMOS/SOS) circuits that are one-third faster. Ion implantation simplifies the integrated circuit fabrication procedure and produces circuits with uniform characteristics.

  4. Biofilm Growth and Detachment of Actinobacillus actinomycetemcomitans

    PubMed Central

    Kaplan, Jeffrey B.; Meyenhofer, Markus F.; Fine, Daniel H.

    2003-01-01

    The gram-negative, oral bacterium Actinobacillus actinomycetemcomitans has been implicated as the causative agent of several forms of periodontal disease in humans. When cultured in broth, fresh clinical isolates of A. actinomycetemcomitans form tenacious biofilms on surfaces such as glass, plastic, and saliva-coated hydroxyapatite, a property that probably plays an important role in the ability of this bacterium to colonize the oral cavity and cause disease. We examined the morphology of A. actinomycetemcomitans biofilm colonies grown on glass slides and in polystyrene petri dishes by using light microscopy and scanning and transmission electron microscopy. We found that A. actinomycetemcomitans developed asymmetric, lobed biofilm colonies that displayed complex architectural features, including a layer of densely packed cells on the outside of the colony and nonaggregated cells and large, transparent cavities on the inside of the colony. Mature biofilm colonies released single cells or small clusters of cells into the medium. These released cells adhered to the surface of the culture vessel and formed new colonies, enabling the biofilm to spread. We isolated three transposon insertion mutants which produced biofilm colonies that lacked internal, nonaggregated cells and were unable to release cells into the medium. All three transposon insertions mapped to genes required for the synthesis of the O polysaccharide (O-PS) component of lipopolysaccharide. Plasmids carrying the complementary wild-type genes restored the ability of mutant strains to synthesize O-PS and release cells into the medium. Our findings suggest that A. actinomycetemcomitans biofilm growth and detachment are discrete processes and that biofilm cell detachment evidently involves the formation of nonaggregated cells inside the biofilm colony that are destined for release from the colony. PMID:12562811

  5. Intraretinal proliferation induced by retinal detachment

    SciTech Connect

    Fisher, S.K.; Erickson, P.A.; Lewis, G.P.; Anderson, D.H. )

    1991-05-01

    Cellular proliferation after retinal detachment was studied by {sup 3}H-thymidine light microscopic autoradiography in cats that had experimental detachments of 0.5-180 days duration. The animals underwent labeling 2 hr before death with an intraocular injection of 200 microCi of {sup 3}H-thymidine. The number of labeled nuclei were counted in 1-micron thick tissue sections in regions of detachment, in regions of the experimental eyes that remained attached, and in control eyes that had no detachments. In the normal eye, in one that had only the lens and vitreous removed, and in the eyes with 0.5- and 1-day detachments, the number of labeled nuclei ranged from 0/mm (0.5-day detachment) to 0.38/mm (lens and vitreous removed only). By 2 days postdetachment, the number of labeled nuclei increased to 2.09/mm. The highest levels of labeling occurred in two animals with detachments of 3 (7.86/mm) and 4 (7.09/mm) days. Thereafter, the numbers declined steadily until near-baseline counts were obtained at 14 days. The number of labeled nuclei was slightly elevated in the attached regions of two animals with 3-day detachments. Labeled cell types included: Mueller cells, astrocytes, pericytes, and endothelial cells of the retinal vasculature, and both resident (microglial cells) and invading macrophages. In an earlier study RPE cells were also shown to proliferate in response to detachment. Thus, these data show that proliferation is a rapid response to detachment, reaching a maximum within 4 days, and that virtually every nonneuronal cell type in the retina can participate in this response. The data suggest that events leading to such clinical manifestations as proliferative vitreoretinopathy and subretinal fibrosis may have their beginnings in this very early proliferative response.

  6. Space processing applications of ion beam technology. [surface finishing, welding, milling and film deposition

    NASA Technical Reports Server (NTRS)

    Grodzka, P. G.

    1977-01-01

    Ion thruster engines for spacecraft propulsion can serve as ion beam sources for potential space processing applications. The advantages of space vacuum environments and the possible gravity effects on thruster ion beam materials operations such as thin film growth, ion milling, and surface texturing were investigated. The direct gravity effect on sputter deposition and vapor deposition processes are discussed as well as techniques for cold and warm welding.

  7. Removal of heavy metal ions from oil shale beneficiation process water by ferrite process

    SciTech Connect

    Mehta, R.K.; Zhang, L.; Lamont, W.E.; Schultz, C.W. . Mineral Resources Inst.)

    1991-01-01

    The ferrite process is an established technique for removing heavy metals from waste water. Because the process water resulting from oil shale beneficiation falls into the category of industrial waste water, it is anticipated that this process may turn out to be a potential viable treatment for oil shale beneficiation process water containing many heave metal ions. The process is chemoremedial because not only effluent water comply with quality standards, but harmful heavy metals are converted into a valuable, chemically stable by-product known as ferrite. These spinel ferrites have magnetic properties, and therefore can be use in applications such as magnetic marker, ferrofluid, microwave absorbing and scavenging material. Experimental results from this process are presented along with results of treatment technique such as sulfide precipitation.

  8. Removal of heavy metal ions from oil shale beneficiation process water by ferrite process

    SciTech Connect

    Mehta, R.K.; Zhang, L.; Lamont, W.E.; Schultz, C.W.

    1991-12-31

    The ferrite process is an established technique for removing heavy metals from waste water. Because the process water resulting from oil shale beneficiation falls into the category of industrial waste water, it is anticipated that this process may turn out to be a potential viable treatment for oil shale beneficiation process water containing many heave metal ions. The process is chemoremedial because not only effluent water comply with quality standards, but harmful heavy metals are converted into a valuable, chemically stable by-product known as ferrite. These spinel ferrites have magnetic properties, and therefore can be use in applications such as magnetic marker, ferrofluid, microwave absorbing and scavenging material. Experimental results from this process are presented along with results of treatment technique such as sulfide precipitation.

  9. Liquid Droplet Detachment and Entrainment in Microscale Flows

    NASA Astrophysics Data System (ADS)

    Hidrovo, Carlos

    2005-11-01

    In this talk we will present a first order study of liquid water detachment and entrainment into air flows in hydrophobic microchannels. Silicon based microstructures consisting of 23 mm long U-shaped channels of different geometry were used for this purpose. The structures are treated with a Molecular Vapor Deposition (MVD) process that renders them hydrophobic. Liquid water is injected through a side slot located 2/3 of the way downstream from the air channel inlet. The water entering the air channel beads up into slugs or droplets that grow in size at this injection location until they fill and flood the channel or are carried away by the air flow. The slugs/droplets dimensions at detachment are correlated against superficial gas velocity and proper dimensionless parameters are postulated and examined to compare hydrodynamic forces against surface tension. It is found that slug/droplet detachment is dominated by two main forces: pressure gradient drag, arising from confinement of a viscous flow in the channel, and inertial drag, arising from the stagnation of the air due to obstruction by the slugs/droplets. A detachment regime map is postulated based on the relative importance of these forces under different flow conditions.

  10. On favorable thermal fields for detached Bridgman growth

    NASA Astrophysics Data System (ADS)

    Stelian, Carmen; Volz, Martin P.; Derby, Jeffrey J.

    2009-06-01

    The thermal fields of two Bridgman-like configurations, representative of real systems used in prior experiments for the detached growth of CdTe and Ge crystals, are studied. These detailed heat transfer computations are performed using the CrysMAS code and expand upon our previous analysis [C. Stelian, A. Yeckel, J.J. Derby, Influence of thermal phenomena on crystal reattachment during the dewetted Bridgman growth, J. Cryst. Growth, in press] that posited a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. Computational results indicate that heat transfer conditions that led to successful detached growth in both of these systems are in accordance with our prior assertion, namely that the prevention of crystal reattachment to the crucible wall requires the avoidance of any undercooling of the melt meniscus during the growth run. Significantly, relatively simple process modifications that promote favorable thermal conditions for detached growth may overcome detrimental factors associated with meniscus shape and crucible wetting. Thus, these ideas may be important to advance the practice of detached growth for many materials.

  11. Existence and Stability of Menisci in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2011-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The Young-Laplace capillary equation was used to calculate the crystal radii of detached states as a function of the pressure differential across the meniscus. The detached states depend on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, and the Bond number. A static stability analysis was performed on the calculated detached states. The stability criterion was the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The conditions considered corresponded to the growth of Ge and InSb, in both terrestrial and microgravity conditions. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes which are single-valued functions of the radius are statically stable in a microgravity environment.

  12. OEDGE Modeling of Detachment Threshold Experiments on DIII-D

    NASA Astrophysics Data System (ADS)

    Elder, J. D.; Stangeby, P. C.; McLean, A. G.; Leonard, A. W.; Watkins, J. G.

    2015-11-01

    A detachment threshold experiment was performed on DIII-D in which the divertor plasma transitioned from attached to weakly detached at the strike point with minimal changes in upstream parameters. The value of Te at the outer strike point measured by Thompson scattering decreased from ~ 10eV (attached) to ~ 2 eV (weakly detached). Both the Langmuir probes and the divertor Thomson diagnostics recorded increases in the particle flux on the order of a factor of two between these divertor conditions. OEDGE is used to model both of these plasma regimes for both L-mode and H-mode discharges. The behaviour of molecular hydrogen is assessed using OEDGE and possible roles of hydrogen molecules in the detachment process are examined. Work supported by the US Department of Energy under DE-FC02-04ER54698, DE-FG02-04ER54578, DE-AC04-94AL85000, DE-AC05-00OR22725, and DE-AC52-07NA27344.

  13. Erbium doping of lithium niobate by the ion exchange process for high-gain optical amplifiers

    NASA Astrophysics Data System (ADS)

    Caccavale, Frederico; Fedorov, Vyacheslav A.; Korkishko, Yuri N.; Morozova, Tamara V.; Sada, Cinzia; Segato, Francesco

    2000-04-01

    The erbium-lithium ion exchange is presented as a method for the erbium local doping of lithium niobate crystals. Ion exchange process is performed immersing the LiNbO3 substrates in a liquid melt, containing erbium ions; due to their high mobility, the lithium ions migrate from the crystal to the melt, and are replaced by erbium ions. A systematic analysis of the doping process is performed, and the influence of the process parameters is investigated: exchange time and temperature, crystal cut direction, composition and chemical reactivity of the Er ions liquid source. By structural (X-Ray Diffraction and Rutherford Backscattering Spectrometry), compositional (Secondary Ion Mass Spectrometry) and spectroscopic techniques (optical spectroscopy and micro-luminescence), the formation of lithium deficient phases and the incorporation of the Er ions into the LiNbO3 matrix is studied.

  14. Dynamics of mussel plaque detachment.

    PubMed

    Desmond, Kenneth W; Zacchia, Nicholas A; Waite, J Herbert; Valentine, Megan T

    2015-09-14

    Mussels are well known for their ability to generate and maintain strong, long-lasting adhesive bonds under hostile conditions. Many prior studies attribute their adhesive strength to the strong chemical interactions between the holdfast and substrate. While chemical interactions are certainly important, adhesive performance is also determined by contact geometry, and understanding the coupling between chemical interactions and the plaque shape and mechanical properties is essential in deploying bioinspired strategies when engineering improved adhesives. To investigate how the shape and mechanical properties of the mussel's plaque contribute to its adhesive performance, we use a custom built load frame capable of fully characterizing the dynamics of the detachment. With this, we can pull on samples along any orientation, while at the same time measuring the resulting force and imaging the bulk deformations of the plaque as well as the holdfast-substrate interface where debonding occurs. We find that the force-induced yielding of the mussel plaque improves the bond strength by two orders of magnitude and that the holdfast shape improves bond strength by an additional order of magnitude as compared to other simple geometries. These results demonstrate that optimizing the contact geometry can play as important a role on adhesive performance as optimizing the chemical interactions as observed in other organisms and model systems. PMID:26223522

  15. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Vujisic, L.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years, especially under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 micrometers, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5 mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 micrometers. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  16. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Motakef, S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years especially, under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 microns, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 microns. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  17. Toward scalable ion traps for quantum information processing

    NASA Astrophysics Data System (ADS)

    Amini, J. M.; Uys, H.; Wesenberg, J. H.; Seidelin, S.; Britton, J.; Bollinger, J. J.; Leibfried, D.; Ospelkaus, C.; VanDevender, A. P.; Wineland, D. J.

    2010-03-01

    In this paper, we report the design, fabrication and preliminary testing of a 150 zone ion trap array built in a 'surface-electrode' geometry microfabricated on a single substrate. We demonstrate the transport of atomic ions between the legs of a 'Y'-type junction and measure the in-situ heating rates for the ions. The trap design demonstrates the use of a basic component design library that can be quickly assembled to form structures optimized for a particular experiment.

  18. Characterization of Surface Features in Detached Grown GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Cobb, S. D.; Volz, M. P.; Schweizer, M.; Kaiser, N.; Carpenter, P. K.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The growth of detached crystals by the Bridgman technique, in which the growing crystal is not in contact with the crucible wall, has been observed both on earth and in microgravity conditions. At present, the mechanisms contributing to the detachment are not completely understood and until recently detachment has not been reproducibly obtained. It is commonly understood that the main factors that promote the occurrence of detached growth include: high contact angle between the melt and the crucible material, high growth angle, and a pressure difference between the annular gap around the solid below the melt and the volume above the melt along the meniscus. These parameters were varied in Bridgman growth experiments to determine the conditions required to achieve detached growth terrestrially in Ge and GeSi alloys. These experiments are in preparation for experiments on the International Space Station (ISS). The detailed objectives of the flight experiments and a description of the growth methods employed are the subject of another presentation at this Conference. Detached crystals were achieved repeatedly in pyrolytic boron nitride ampoules when a pressure difference was employed. All crystals, except for those grown in fused silica ampoules, were easily removed from their containers, however, this fact alone is not sufficient to infer detached growth. Detachment was verified by comparing profilometer measurements of the radius of the samples with observations of the sample surfaces using optical and electron microscopy. The surfaces of the attached areas of the crystals had the same shape and surface texture as the interior crucible wall. Regions of detached growth contained many unique features and crystal facets could usually be observed. Several of these surface features have been correlated with mechanisms of detachment or free-surface growth and others to processing events or conditions.

  19. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. In microgravity, the parameters that influence the existence of a stable gap are the growth angle of the solidifying crystal, the contact angle between the melt and the crucible wall, and the pressure difference across the meniscus. During actual crystal growth, the initial crystal radius will not have the precise value required for stable detached growth. Beginning with a crystal diameter that differs from stable conditions, numerical calculations are used to analyze the transient crystal growth process. Depending on the initial conditions and growth parameters, the crystal shape will either evolve towards attachment at the crucible wall, towards a stable gap width, or inwards towards eventual collapse of the meniscus. Dynamic growth stability is observed only when the sum of the growth and contact angles exceeds 180 degrees.

  20. The highly eccentric detached eclipsing binaries in ACVS and MACC

    NASA Astrophysics Data System (ADS)

    Shivvers, Isaac; Bloom, Joshua S.; Richards, Joseph W.

    2014-06-01

    Next-generation synoptic photometric surveys will yield unprecedented (for the astronomical community) volumes of data and the processes of discovery and rare-object identification are, by necessity, becoming more autonomous. Such autonomous searches can be used to find objects of interest applicable to a wide range of outstanding problems in astronomy, and in this paper we present the methods and results of a largely autonomous search for highly eccentric detached eclipsing binary systems in the Machine-learned All-Sky Automated Survey Classification Catalog. 106 detached eclipsing binaries with eccentricities of e ≳ 0.1 are presented, most of which are identified here for the first time. We also present new radial-velocity curves and absolute parameters for six of those systems with the long-term goal of increasing the number of highly eccentric systems with orbital solutions, thereby facilitating further studies of the tidal circularization process in binary stars.

  1. Heat and detachment in core-complex extension

    NASA Technical Reports Server (NTRS)

    Lucchitta, I.

    1985-01-01

    It is proposed here that the Miocene to Recent structural and volcanic features of the Basin and Range Province can be explained by a single thermotectonic process acting through time. This process consists of a thermal pulse resulting in a high-temperature regime that includes a steep thermal front moving first up toward the topographic surface, then down owing to cooling induced by a combination of convection and conduction. Within the front is a condition defining a critical surface that separates brittle from ductile behavior, and is marked by a nearly horizonal detachment fault. The most prominent and structurally highest position of the detachment results from interaction between the critical surface and a hydrothermal system near the topographic surface. These various features can be superposed on older ones through thermal remobilization or structural reactivation.

  2. Electrowetting-on-dielectric assisted bubble detachment in a liquid film

    NASA Astrophysics Data System (ADS)

    Wang, S.; Chen, H. H.; Chen, C. L.

    2016-05-01

    Drawing inspiration from electrowetting-controlled droplets, the potential advantages of electrowetting for bubble dynamics are investigated experimentally. In this study, we present and characterize an open electrowetting-on-dielectric (EWOD) system for studying the bubble behavior. Both detachment and non-detachment processes of a small single bubble in a thick liquid film under EWOD were experimentally observed. The measurement of contact angle changes of the small air bubble shows relatively good agreement with Young-Lippmann's equation within the majority of the test voltage range, except for the saturation region. Meanwhile, we have experimentally demonstrated both the characteristics of single- and double-bubble detachment within a thin liquid film. Direct bubble detachment may occur when it touches the gas-liquid interface during the process of contact angle change, while indirect bubble detachment is highly possible due to the dramatic oscillation resulting from the detachment of adjacent bubbles. The experimental results demonstrate that EWOD can effectively facilitate the detachment of small air bubble in a thin liquid film.

  3. Quantifying micron-scale grain detachment during weathering experiments on limestone

    NASA Astrophysics Data System (ADS)

    Levenson, Yael; Emmanuel, Simon

    2016-01-01

    Weathering in carbonate rocks is often assumed to be governed by chemical dissolution. Nevertheless, chemical processes can be coupled to mechanical mechanisms, with small grains undergoing partial dissolution along grain boundaries, followed by detachment from the rock surface. Crucially, this process can even extend down to the micron-scale. Although chemo-mechanical detachment could be critical for the understanding of carbonate weathering at the global scale, the role it plays has not been directly quantified. To calculate the contribution of grain detachment to surface retreat rates, and to determine the impact of the flow regime, we carried out a series of flow-through weathering experiments on micritic limestone. Using atomic force microscopy, we obtained high resolution in situ data of surface topography for reacting rock surfaces. In all the experiments, both grain detachment and chemical dissolution were observed. Under the laminar flow conditions we explored, we found no clear correlation between flow rate and the size of detached grains, or between the flow rate and the frequency of grain detachment events. Importantly, our results establish that grain detachment contributes significantly to the overall surface retreat, on average accelerating mass loss by 38%. In addition to speeding up weathering, this micron-scale mechanism could also influence the evolution of porosity in aquifers and hydrocarbon reservoirs, and provide a natural flux of colloids that could transport heavy metals or radionuclides in groundwater.

  4. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition.

    PubMed

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-01-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism. PMID:27270334

  5. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition

    NASA Astrophysics Data System (ADS)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-06-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism.

  6. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition

    PubMed Central

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-01-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism. PMID:27270334

  7. Detached plasma in Saturn's front side magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1983-01-01

    Plasma observations in the outer front side Saturnian magnetosphere are discussed which indicate the existence of dense flux tubes outside the plasma sheets. It is suggested that flux tubes are detached from the plasma sheet by a centifugally driven flute instability. The same instability leads to a dispersal of Titan-injected plasma. It is shown that the detached flux tubes will probably break open as they convect into the nightside magnetotail and lose their content in the form of a planetary wind.

  8. Pre-equilibrium decay processes in energetic heavy ion reactions

    SciTech Connect

    Blann, M.

    1986-04-15

    The Boltzmann master equation (BME) is defined for application to precompound decay in heavy ion reactions in the 10 100 MeV/nucleon regime. Predicted neutron spectra are compared with measured results for central collisions of /sup 20/Ne and /sup 12/C with /sup 165/Ho target nuclei. Comparisons are made with subthreshold ..pi../sup 0/ yields in heavy ion reactions between 35 and 84 MeV/nucleon, and with the ..pi../sup 0/ spectra. The BME is found to be an excellent tool for investigating these experimentally observed aspects of non-equilibrium heavy ion reactions. 18 refs., 8 figs.

  9. Ion implantation processing of GaN epitaxial layers

    SciTech Connect

    Tan, H.H.; Williams, J.S.; Zou, J.; Cockayne, D.J.H.; Pearton, S.J.; Yuan, C.

    1996-12-31

    Ion implantation induced-damage build up in epitaxial GaN layers grown on sapphire has been analyzed by ion channeling and electron microscopy techniques. The epitaxial layers are extremely resistant to ion beam damage in that substantial dynamic annealing of implantation disorder occurs even at liquid nitrogen temperatures. Amorphous layers can be formed in some cases if the implantation dose is high enough. However, the damage (amorphous or complex extended defects) that is formed is also extremely difficult to remove during annealing and required temperatures in excess of 1,100 C.

  10. Anion A– • HX Clusters with Reduced Electron Binding Energies: Proton vs Hydrogen Atom Relocation Upon Electron Detachment

    SciTech Connect

    Wang, Xue B.; Kass, Steven R.

    2014-12-10

    Clustering an anion with one or more neutral molecules is a stabilizing process that enhances the oxidation potential of the complex relative to the free ion. Several hydrogen bond clusters (i.e., A— • HX, where A— = H2PO4— and CF3CO2— and HX = MeOH, PhOH, and Me2NOH or Et2NOH) are examined by photoelectron spectroscopy and M06-2X and CCSD(T) computations. Remarkably, these species are experimentally found to have adiabatic detachment energies that are smaller than those for the free ion and reductions of 0.47 to 1.87 eV are predicted computationally. Hydrogen atom and proton transfers upon vertical photodetachment are two limiting extremes on the neutral surface in a continuum of mechanistic pathways that account for these results, and the whole gamut of possibilities are predicted to occur.

  11. WASTEWATER DEMINERALIZATION BY CONTINUOUS COUNTER-CURRENT ION EXCHANGE PROCESS

    EPA Science Inventory

    A wastewater demineralization study employing a 38 lpm (10 gpm) continuous counter-current ion exchange pilot plant, manufactured by the Chemical Separations Corporation, Oak Ridge, Tennessee, has been conducted at the County Sanitation Districts, Pomona Research Facility, Pomona...

  12. Influence of hard water ions on the growth of salmonella in poultry processing water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of magnesium and calcium ions in process water on the growth of Salmonella was evaluated and related to the contamination in process wastewater. Salmonella typhimurium was grown in the laboratory and exposed to 500 mg/kg and 1000 mg/kg of magnesium and calcium ions to simulate hard pr...

  13. Ion distribution measurements to probe target and plasma processes in electronegative magnetron discharges. II. Positive ions

    SciTech Connect

    Welzel, Th.; Ellmer, K.; Naumov, S.

    2011-04-01

    Spectra of the ion mass and energy distributions of positive ions in reactive (Ar/O{sub 2}) and nonreactive (Ar) dc magnetron sputtering discharges have been investigated by energy-resolved mass spectrometry. The results of three sputter target materials, i.e., Cu, In, and W are compared to each other. Besides the main gas constituents, mass spectra reveal a variety of molecular ions which are dependent on the target material. In reactive mode, ArO{sup +} is always observed in Ar/O{sub 2} but molecules containing Ar and the metal were exclusively found for the Cu target. The occurrence of the different ions is explained in the context of their bond strengths obtained from density functional theory calculations. The energy spectra generally contain the known low-energy peak corresponding to the plasma potential. Differently extended high-energy tails due to sputtered material were observed for the different targets. Besides these, high-energetic ions were detected with up to several 100 eV. Their energies are significantly different for Ar{sup +} and O{sup +} with Ar{sup +} strongly depending on the target material. The spectra are discussed together with results from transport of ions in matter (TRIM) calculation to elucidate the origin of these energetic ions.

  14. Stability of Menisci in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, Konstantin; Volz, Martin P.

    2013-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The meniscus shape depends on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, the gas pressure differential, the Weber number describing the rotation rate of the crucible, and the Bond number. Only some of the meniscus shapes are stable and the stability criterion is the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The effects of confined gas volumes above and below the melt and crucible rotation are evaluated. The analysis is applicable to the non-stationary case where the crystal radius changes during growth. Static stability maps (crystal radius versus pressure differential) are obtained for a series of Bond numbers, growth angles and Weber numbers. Also, the specific cases of Ge and InSb, in both terrestrial and microgravity conditions, are analyzed. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes are statically stable in a microgravity environment.

  15. Microfabricated Surface-Electrode Ion Trap for Scalable Quantum Information Processing

    SciTech Connect

    Seidelin, S.; Chiaverini, J.; Reichle, R.; Bollinger, J.J.; Leibfried, D.; Britton, J.; Wesenberg, J.H.; Blakestad, R.B.; Epstein, R.J.; Hume, D.B.; Itano, W.M.; Jost, J.D.; Langer, C.; Ozeri, R.; Shiga, N.; Wineland, D.J.

    2006-06-30

    Individual laser-cooled {sup 24}Mg{sup +} ions are confined in a linear Paul trap with a novel geometry where gold electrodes are located in a single plane and the ions are trapped 40 {mu}m above this plane. The relatively simple trap design and fabrication procedure are important for large-scale quantum information processing (QIP) using ions. Measured ion motional frequencies are compared to simulations. Measurements of ion recooling after cooling is temporarily suspended yield a heating rate of approximately 5 motional quanta per millisecond for a trap frequency of 2.83 MHz, sufficiently low to be useful for QIP.

  16. [Treatment of serous macular retinal detachment with antihistamines].

    PubMed

    Kirschfeld, K

    2015-01-01

    The etiology of retinal detachment in central serous retinopathy (CSR) is unknown; however, three facts are generally accepted: (1) the serous exudate which raises the layers of the receptors/pigment epithelium is formed due to hyperpermeability in the choriocapillaries, (2) patients frequently suffer from headaches and (3) stress promotes the incidence of CSR. A high blood plasma histamine concentration can cause the abovementioned symptoms which suggests that histamine might provoke CSR. Within 1 week after administration of the antihistamine loratadin a considerable reduction in the retinal exudate and restoration of vision were observed. This supports the hypothesis that histamine could be involved in the process of retinal detachment. Further investigations and large scale clinical trials should clarify if this hypothesis can be proved or disproved and whether antihistamines can be used for age-related macular degeneration (AMD). PMID:25278347

  17. Magnetic Nozzle and Plasma Detachment Scenario

    NASA Astrophysics Data System (ADS)

    Breizman, Boris

    2007-11-01

    Some plasma propulsion concepts rely on a strong magnetic field to guide the plasma flow through the thruster nozzle. The question then arises of how the magnetically controlled plasma can detach from the spacecraft. This talk presents a magnetohydrodynamic detachment scenario in which the plasma stretches the magnetic field lines to infinity [1]. Such a scenario is of particular interest for high-power thrusters. As plasma flows along the magnetic field lines, the originally sub-Alfv'enic flow becomes super-Alfv'enic: this transition is similar to what occurs in the solar wind [2]. In order to describe the detachment quantitatively, the ideal MHD equations have been solved analytically for a plasma flow in a slowly diverging nozzle. The solution exhibits a well-behaved transition from sub- to super- Alfv'enic flow inside the nozzle and a rarefaction wave at the edge of the outgoing flow. The magnetic field in the detached plume is almost entirely due to the plasma currents. It is shown that efficient detachment is feasible if the nozzle is sufficiently long. In order to extend the detachment model beyond the idealizations of analytical theory, a Lagrangian fluid code has been developed to solve steady-stated MHD equations and to optimize nozzle efficiency by adjusting the magnetic coil configuration. This numerical tool enables broad parameter scan with modest computational requirements (single workstation). The code has been benchmarked against the idealized analytical picture of plasma detachment and then used to investigate more realistic nozzle configurations that are not analytically tractable. Most recently, the code has been used to interpret experimental data from the Detachment Demonstration Experiment (DDEX) [3] facility at NASA Marshall Space Flight Center. In collabotation with: M. Tushentsov, A. Arefiev, R. Bengtson, J.Meyers (University of Texas at Austin), D. Chavers, C. Dobson, J. Jones (Marshall Space Flight Center), B.Schuettpelz, (University of

  18. Theoretical investigations of plasma processes in the ion bombardment thruster

    NASA Technical Reports Server (NTRS)

    Wilhelm, H. E.

    1975-01-01

    A physical model for a thruster discharge was developed, consisting of a spatially diverging plasma sustained electrically between a small ring cathode and a larger ring anode in a cylindrical chamber with an axial magnetic field. The associated boundary-value problem for the coupled partial differential equations with mixed boundary conditions, which describe the electric potential and the plasma velocity fields, was solved in closed form. By means of quantum-mechanical perturbation theory, a formula for the number S(E) of atoms sputtered on the average by an ion of energy E was derived from first principles. The boundary-value problem describing the diffusion of the sputtered atoms through the surrounding rarefied electron-ion plasma to the system surfaces of ion propulsion systems was formulated and treated analytically. It is shown that outer boundary-value problems of this type lead to a complex integral equation, which requires numerical resolution.

  19. A mechanical model of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2012-08-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate, typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular and RPE pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed lesions in which the tissue has a higher choroidal hydraulic conductivity, has insufficient RPE pump activity, or has defective adhesion bonds. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. The corresponding stable blister radius and shape are calculated. Our analysis provides a quantitative description of the physical mechanisms involved in exudative retinal detachments and can help guide the development of retinal reattachment protocols or preventative procedures.

  20. Effects of near soil surface characteristics on soil detachment by overland flow in a natural succession grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetation restoration probably has great effects on the process of soil detachment. This study was conducted to investigate the effects of near soil surface characteristics on soil detachment by overland flow in a 7-year naturally restored grassland. Four treatments were designed to characterize th...

  1. Characterization of silicon-gate CMOS/SOS integrated circuits processed with ion implantation

    NASA Technical Reports Server (NTRS)

    Woo, D. S.

    1977-01-01

    Progress in developing the application of ion implantation techniques to silicon gate CMOS/SOS processing is described. All of the conventional doping techniques such as in situ doping of the epi-film and diffusion by means of doped oxides are replaced by ion implantation. Various devices and process parameters are characterized to generate an optimum process by the use of an existing SOS test array. As a result, excellent circuit performance is achieved. A general description of the all ion implantation process is presented.

  2. Electrolytic process to produce sodium hypochlorite using sodium ion conductive ceramic membranes

    SciTech Connect

    Balagopal, Shekar; Malhotra, Vinod; Pendleton, Justin; Reid, Kathy Jo

    2012-09-18

    An electrochemical process for the production of sodium hypochlorite is disclosed. The process may potentially be used to produce sodium hypochlorite from seawater or low purity un-softened or NaCl-based salt solutions. The process utilizes a sodium ion conductive ceramic membrane, such as membranes based on NASICON-type materials, in an electrolytic cell. In the process, water is reduced at a cathode to form hydroxyl ions and hydrogen gas. Chloride ions from a sodium chloride solution are oxidized in the anolyte compartment to produce chlorine gas which reacts with water to produce hypochlorous and hydrochloric acid. Sodium ions are transported from the anolyte compartment to the catholyte compartment across the sodium ion conductive ceramic membrane. Sodium hydroxide is transported from the catholyte compartment to the anolyte compartment to produce sodium hypochlorite within the anolyte compartment.

  3. Dual ion beam processed diamondlike films for industrial applications

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Kussmaul, M. T.; Banks, B. A.; Sovey, J. S.

    1991-01-01

    Single and dual beam ion source systems are used to generate amorphous diamondlike carbon (DLC) films, which were evaluated for a variety of applications including protective coatings on transmitting materials, power electronics as insulated gates and corrosion resistant barriers. A list of the desirable properties of DLC films along with potential applications are presented.

  4. ION-EXCHANGE PROCESSES AND MECHANISMS IN GLASSES

    EPA Science Inventory

    Recent performance assessment calculations of a disposal system at Hanford, Washington for low activity waste glass show that a Na ion-exchange reaction can effectively increase the radionuclide release rate by over a factor of 1000 and so is a major factor that currently limits ...

  5. Ion distribution measurements to probe target and plasma processes in electronegative magnetron discharges. I. Negative ions

    SciTech Connect

    Welzel, Th.; Ellmer, K.; Naumov, S.

    2011-04-01

    Mass and energy spectra of negative ions in magnetron sputtering discharges have been investigated with an energy-dispersive mass spectrometer. The dc magnetrons have been operated in the same reactive Ar/O{sub 2} atmosphere but with three different target materials: Cu, In, and W. Besides negative ions of the working gas, a variety of target metal containing negative molecular ions were found in the discharge. Their occurrence is strongly dependent on the target material. It has been correlated to the electron affinity and the bond strength of the molecules which has been calculated by density functional theory. Energy spectra of the negative ions exhibit three contributions that are clearly distinguishable. Their different origin is discussed as electron attachment in the gas phase and at the target surface, and molecule fragmentation during transport from target to substrate. The latter two contributions again significantly deviate for different target material. The high-energy part of the spectra has been analyzed with respect to the energy the particles gain upon release from the surface. It suggests that bigger molecules formed on the surface are released by ion-assisted desorption.

  6. Negative ion production and beam extraction processes in a large ion source (invited)

    NASA Astrophysics Data System (ADS)

    Tsumori, K.; Ikeda, K.; Nakano, H.; Kisaki, M.; Geng, S.; Wada, M.; Sasaki, K.; Nishiyama, S.; Goto, M.; Serianni, G.; Agostinetti, P.; Sartori, E.; Brombin, M.; Veltri, P.; Wimmer, C.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O.

    2016-02-01

    Recent research results on negative-ion-rich plasmas in a large negative ion source have been reviewed. Spatial density and flow distributions of negative hydrogen ions (H-) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a photodetachment (PD) signal of a Langmuir probe. The PD signal is converted to local H- density from signal calibration to a scanning cavity ring down PD measurement. Introduction of Cs changes the slope of plasma potential local distribution depending upon the plasma grid bias. A higher electron density H2 plasma locally shields the bias potential and behaves like a metallic free electron gas. On the other hand, the bias and extraction electric fields penetrate in a Cs-seeded electronegative plasma even when the electron density is similar. Electrons are transported by the penetrated electric fields from the driver region along and across the filter and electron deflection magnetic fields. Plasma ions exhibited a completely different response against the penetration of electric fields.

  7. Negative ion production and beam extraction processes in a large ion source (invited).

    PubMed

    Tsumori, K; Ikeda, K; Nakano, H; Kisaki, M; Geng, S; Wada, M; Sasaki, K; Nishiyama, S; Goto, M; Serianni, G; Agostinetti, P; Sartori, E; Brombin, M; Veltri, P; Wimmer, C; Nagaoka, K; Osakabe, M; Takeiri, Y; Kaneko, O

    2016-02-01

    Recent research results on negative-ion-rich plasmas in a large negative ion source have been reviewed. Spatial density and flow distributions of negative hydrogen ions (H(-)) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a photodetachment (PD) signal of a Langmuir probe. The PD signal is converted to local H(-) density from signal calibration to a scanning cavity ring down PD measurement. Introduction of Cs changes the slope of plasma potential local distribution depending upon the plasma grid bias. A higher electron density H2 plasma locally shields the bias potential and behaves like a metallic free electron gas. On the other hand, the bias and extraction electric fields penetrate in a Cs-seeded electronegative plasma even when the electron density is similar. Electrons are transported by the penetrated electric fields from the driver region along and across the filter and electron deflection magnetic fields. Plasma ions exhibited a completely different response against the penetration of electric fields. PMID:26932108

  8. Time-resolved investigation of ionization processes in the Dresden Electron Beam Ion Source

    SciTech Connect

    Zschornack, G.; Heller, R.; Kreller, M.; Landgraf, S.; Grossmann, F.; Kentsch, U.; Ovsyannikov, V.P.; Schmidt, M.; Ullmann, F.

    2006-03-15

    The emission of characteristic x-ray lines of iron and krypton ions was measured in dependence on the confinement time in an Electron Beam Ion Source, the DRESDEN EBIS. Primarily the measurement was focused on x-ray lines from dielectronic recombination (DR) processes. Due to the sharp resonant character of DR processes the formation of individual ion charge states can be observed at different electron energies (resonance energies) with time-resolved energy-dispersive x-ray spectroscopy. In the case of iron ions, experimentally observed resonance energies are compared to resonance energies calculated with the Flexible Atomic Code (FAC). Further, on outer-shell K{sub {alpha}} x-ray satellites of krypton ions are time-resolve analyzed to construct the evolution of the ionization of krypton ions in the electron beam.

  9. Space Plasma Ion Processing of Ilmenite in the Lunar Soil: Insights from In-Situ TEM Ion Irradiation Experiments

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Keller, L. P.

    2007-01-01

    Space weathering on the moon and asteroids results largely from the alteration of the outer surfaces of regolith grains by the combined effects of solar ion irradiation and other processes that include deposition of impact or sputter-derived vapors. Although no longer considered the sole driver of space weathering, solar ion irradiation remains a key part of the space weathering puzzle, and quantitative data on its effects on regolith minerals are still in short supply. For the lunar regolith, previous transmission electron microscope (TEM) studies performed by ourselves and others have uncovered altered rims on ilmenite (FeTiO3) grains that point to this phase as a unique "witness plate" for unraveling nanoscale space weathering processes. Most notably, the radiation processed portions of these ilmenite rims consistently have a crystalline structure, in contrast to radiation damaged rims on regolith silicates that are characteristically amorphous. While this has tended to support informal designation of ilmenite as a "radiation resistant" regolith mineral, there are to date no experimental data that directly and quantitatively compare ilmenite s response to ion radiation relative to lunar silicates. Such data are needed because the radiation processed rims on ilmenite grains, although crystalline, are microstructurally and chemically complex, and exhibit changes linked to the formation of nanophase Fe metal, a key space weathering process. We report here the first ion radiation processing study of ilmenite performed by in-situ means using the Intermediate Voltage Electron Microscope- Tandem Irradiation facility (IVEM-Tandem) at Argonne National Laboratory. The capability of this facility for performing real time TEM observations of samples concurrent with ion irradiation makes it uniquely suited for studying the dose-dependence of amorphization and other changes in irradiated samples.

  10. Integrated System Technologies for Modular Trapped Ion Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Crain, Stephen G.

    Although trapped ion technology is well-suited for quantum information science, scalability of the system remains one of the main challenges. One of the challenges associated with scaling the ion trap quantum computer is the ability to individually manipulate the increasing number of qubits. Using micro-mirrors fabricated with micro-electromechanical systems (MEMS) technology, laser beams are focused on individual ions in a linear chain and steer the focal point in two dimensions. Multiple single qubit gates are demonstrated on trapped 171Yb+ qubits and the gate performance is characterized using quantum state tomography. The system features negligible crosstalk to neighboring ions (< 3e-4), and switching speeds comparable to typical single qubit gate times (< 2 mus). In a separate experiment, photons scattered from the 171Yb+ ion are coupled into an optical fiber with 63% efficiency using a high numerical aperture lens (0.6 NA). The coupled photons are directed to superconducting nanowire single photon detectors (SNSPD), which provide a higher detector efficiency (69%) compared to traditional photomultiplier tubes (35%). The total system photon collection efficiency is increased from 2.2% to 3.4%, which allows for fast state detection of the qubit. For a detection beam intensity of 11 mW/cm 2, the average detection time is 23.7 mus with 99.885(7)% detection fidelity. The technologies demonstrated in this thesis can be integrated to form a single quantum register with all of the necessary resources to perform local gates as well as high fidelity readout and provide a photon link to other systems.

  11. Real-time control of ion density and ion energy in chlorine inductively coupled plasma etch processing

    NASA Astrophysics Data System (ADS)

    Chang, Cheng-Hung; Leou, Keh-Chyang; Lin, Chaung; Lin, Tsan-Lang; Tseng, Chih-Wei; Tsai, Chuen-Horng

    2003-07-01

    In this study, we have experimentally demonstrated the real-time closed-loop control of both ion density and ion energy in a chlorine inductively coupled plasma etcher. To measure positive ion density, the trace rare gases-optical emission spectroscopy is used to measure the chlorine positive ion density. An rf voltage probe is adopted to measure the root-mean-square rf voltage on the electrostatic chuck which is linearly dependent on sheath voltage. One actuator is a 13.56 MHz rf generator to drive the inductive coil seated on a ceramic window. The second actuator is also a 13.56 MHz rf generator to power the electrostatic chuck. The closed-loop controller is designed to compensate for process drift, process disturbance, and pilot wafer effect and to minimize steady-state error of plasma parameters. This controller has been used to control the etch process of unpatterned polysilicon. The experimental results showed that the closed-loop control had a better repeatability of plasma parameters compared with open-loop control. The closed-loop control can eliminate the process disturbance resulting from reflected power. In addition, experimental results also demonstrated that closed-loop control has a better reproducibility in etch rate as compared with open-loop control.

  12. Electron-ion collisions. [Basic physics of inelastic processes of excitation, ionization, and recombination

    SciTech Connect

    Crandall, D.H.

    1982-01-01

    This discussion concentrates on basic physics aspects of inelastic processes of excitation, ionization, and recombination that occur during electron-ion collisions. Except for cases of illustration along isoelectronic sequences, only multicharged (at least +2) ions will be specifically discussed with some emphasis of unique physics aspects associated with ionic charge. The material presented will be discussed from a primarily experimental viewpoint with most attention to electron-ion interacting beams experiments.

  13. Surface ion trap structures with excellent optical access for quantum information processing

    NASA Astrophysics Data System (ADS)

    Maunz, P.; Blain, M.; Benito, F.; Chou, C.; Clark, C.; Descour, M.; Ellis, R.; Haltli, R.; Heller, E.; Kemme, S.; Sterk, J.; Tabakov, B.; Tigges, C.; Stick, D.

    2013-05-01

    Microfabricated surface electrode ion traps are necessary for the advancement of trapped ion quantum information processing as it offers a scalable way for realizing complex trap structures capable of storing and controlling many ions. The most promising way of performing two-qubit quantum gates in a chain of trapped ions is to focus laser beams on individual ions of the chain to drive gates. However, in surface ion traps the close proximity of the ions to the surface and the size of the chips usually cannot accommodate the tightly focused laser beams necessary to address individual ions parallel to the chip surface. Here we present a surface electrode ion trap monolithically fabricated in standard silicon technology that implements a linear quadrupole trap on a bowtie shaped chip with a narrow section that is only 1.2 mm wide. Laser beams parallel to the surface can be focused down to a waist of 4 μm with enough separation from the trap chip to prevent light scattering. The trap structure incorporates two Y-junctions for reordering ions and is optimized for quantum information processing. This work was supported by the Intelligence Advanced Research Projects Activity (IARPA). Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. Study of Electron Transfer Processes between Simple Plasma Ions and Electron Attaching Gases

    NASA Astrophysics Data System (ADS)

    Williams, Ted; Adams, Nigel; Babcock, Lucia

    1998-11-01

    CCl4 and SF6 are gases that rapidly attach electrons. They are used in etchant plasmas and in high power switches to prevent breakdown. This attachment results in a simple negative ion chemistry that can be well characterized. A concurrent series of reactions involving positive ions also occurs, with ionization eventually being removed by ion-ion mutual neutralization. However, unlike the negative ion chemistry, the positive ion chemistry is more complex and has not been well characterized. Common plasma ions are those of the rare and diatomic gases, along with impurity ions such as H_2O^+ and H_3O^+. Reactions of these ions with CCl4 and SF6 generally occur rapidly by dissociative electron transfer. Some exceptions have been observed when the reactant ion contains an H-atom(s), such as the production of HCl when H_3^+ reacts with CCl_4. Since these reactions involve a fixed amount of energy, they bear similarity to photoelectron and photoelectron-photoion coincidence studies of these electron attaching gases in which only Franck-Condon transitions can occur. Comparision of product ions observed and rate coefficients gives better insights into the mechanism of the electron transfer process. Support by NSF AST-9415485 is gratefully acknowledged.

  15. Dependence of electric potentials at trench surfaces on ion angular distribution in plasma etching processes

    NASA Astrophysics Data System (ADS)

    Palov, A. P.; Mankelevich, Yu A.; Rakhimova, T. V.; Baklanov, M. R.

    2016-03-01

    Ion-stimulated etching of dielectrics in radio frequency plasma results in positive charging of a trench bottom because of the significant difference in the angular distribution functions of ions and electrons. They are anisotropic for ions and quasi-isotropic for electrons. The charging leads to a decrease in the energy of the ions bombarding the trench bottom and to undesirable sputtering of the walls near the trench bottom because of the curving of the ion trajectories. This process is normally investigated by Monte Carlo methods in the absence of experimental data. In this paper the analytical dependence of the ion flux bombarding the trench bottom on a trench aspect ratio and ion angular distribution function is obtained. Numerical calculations of the electric potential on the trench bottom for a set of trench aspect ratios and angles of the ion angular distribution function were performed based on a Monte Carlo method to demonstrate the ion flux and electric potential correlated well with each other. The proposed formula for an ion flux is suggested to be helpful for analyzing charging the trenches with different aspect ratios in plasma with an arbitrary angular ion distribution function.

  16. Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment

    SciTech Connect

    Lin, Yuehe; Choi, Daiwon; Wang, Jun; Bontha, Jagannadha R.

    2009-01-01

    The objective of our work is to develop an electrically switched ion exchange (ESIX) system based on conducting polymer/carbon nanotube (CNT) nanocomposites as a new and cost-effective approach for removal of radioactive cesium, chromate, and perchlorate from contaminated groundwater. The ESIX technology combines ion exchange and electrochemistry to provide a selective, reversible method for the removal of target species from wastewater. In this technique, an electroactive ion exchange layer is deposited on a conducting substrate, and ion uptake and elution are controlled directly by modulation of the potential of the layer. ESIX offers the advantages of highly-efficient use of electrical energy combined with no secondary waste generation. Recently, we have improved upon the ESIX process by modifying the conducting substrate with carbon nanotubes prior to the deposition of the electroactive ion exchanger. The nanomaterial-based electroactive ion exchange technology will remove cesium-137, chromate, and perchlorate rapidly from wastewater. The high porosity and high surface area of the electroactive ion exchange nanocomposites results in high loading capacity and minimize interferences for non-target species. Since the ion adsorption/desorption is controlled electrically without generating a secondary waste, this electrically active ion exchange process is a green process technology that will greatly reduce operating costs.

  17. Terminal Stage Subduction and Slab Detachment: From Structure to Dynamics

    NASA Astrophysics Data System (ADS)

    Wortel, M. J.; Spakman, W.; Govers, R.

    2007-12-01

    In this contribution we focus on terminal stage subduction, often triggered by continent-continent or arc-continent collision. Rupturing of subducted lithosphere, including slab detachment, is a key process in this stage. Seismic tomography information on the 3D structure of subduction zones has been key towards developing a better understanding of subduction processes. We show how structural information on lithosphere and mantle structure, obtained from seismic tomography, can be used to formulate hypotheses concerning the evolution and dynamics of subduction zones which (1) can be subjected to numerical modeling to investigate the physical soundness of the hypotheses, and (2) can subsequently be tested against geological, geophysical, and geodetical data to assess their general or regional validity. In combination, this approach increases our understanding of the relation between deep processes and the geological processes at the surface. The landlocked basin setting of the Mediterranean region provides unique opportunities to study terminal stage subduction and its consequences. Subducted lithosphere is subject to various types of rupturing: Slab detachment, vertical slab tearing and the formation of STEP (tear) faults have been identified and analysed. The different Mediterranean arc systems being in slightly different stages of evolution provides additional clues towards unraveling the dynamics of the process. Using examples from the western-central and eastern Mediterranean, we show how temporal and spatial variations in slab structure affect the dynamics and stress field of convergent plate boundaries, with arc migration and back-arc extension as a prominent expression. In addition, terminal stage subduction appears to be have played a crucial role in Italian magmatism. Terminal stage subduction involving slab detachment is a strongly transient stage with great impact on geological processes, on a wide variety of scales. The information obtained from

  18. Evaluation and management of pediatric rhegmatogenous retinal detachment

    PubMed Central

    Wenick, Adam S.; Barañano, David E.

    2012-01-01

    Pediatric rhegmatogenous retinal detachments are rare, accounting for less than ten percent of all rhegmatogenous retinal detachments. While most retinal detachments in the adult population are related to posterior vitreous detachment, pediatric retinal detachment are often related to trauma or an underlying congenital abnormalities or genetic syndrome. The anatomy of pediatric eyes, the often late presentation of the disease, and the high incidence of bilateral pathology in children all pose significant challenges in the management of these patients. We discuss the epidemiology of pediatric rhegmatogenous retinal detachment, review the genetic syndromes associated with a high incidence of retinal detachment, and examine other common causes of retinal detachment in this age group. We then outline an approach to evaluation and management and describe the expected outcomes of repair of retinal detachment in the pediatric population. PMID:23961003

  19. III-Nitride ion implantation and device processing

    SciTech Connect

    Zolper, J.C.; Shul, R.J.; Baca, A.G.; Pearton, S.J.; Abernathy, C.R.; Wilson, R.G.; Stall, R.A.; Shur, M.

    1996-06-01

    Ion implantation doping and isolation has played a critical role in realizing high performance photonic and electronic devices in all mature semiconductor materials; this is also expected for binary III-Nitride materials (InN, GaN, AlN) and their alloys as epitaxy improves and more advanced device structures fabricated. This paper reports on recent progress in ion implantation doping of III-Nitride materials that has led to the first demonstration of a GaN JFET (junction field effect transistor). The JFET was fabricated with all ion implantation doping; in particular, p-type doping of GaN with Ca has been demonstrated with an estimated acceptor ionization energy of 169 meV. O-implantation has also been studied and shown to yield n-type conduction with an ionization energy of {similar_to}29 meV. Neither Ca or O display measurable redistribution during a 1125 C, 15 s activation anneal which sets an upper limit on their diffusivity at this temperature of 2.7{times}10{sup {minus}13}cm{sup 2}/s.

  20. Optical Performance And Process Characterizations Of Several High Contrast Metal-Ion-Free Developer Processes

    NASA Astrophysics Data System (ADS)

    Petersen, John S.; Kozlowski, Alan E.

    1984-05-01

    Projection print quality is dependent upon the response of the resist/developer system to the optically projected image. For this reason, it is critical, during process optimization, to relate final pattern quality to both the chemical and physical contrast terms. One method for doing this is to monitor resist/developer response in the absence and then the presence of diffracted light. These results are then compared to the predicted optical requirements. For best performance, the resist/developer (or chemical) contrast must ex-ceed that of the potential optical (or physical) contrast. To do rapid contrast compari-sons it is convenient to relate the chemical contrast term,r, to the physical contrast term MTF, via the CMTF1: where the CMTF = (1014- 1)/(lol* 1) = (Ethreshold Einitial)/ (Ethreshold Einitial) and the MTF=(Emax Emin)/(Emax + EmiA. Perfect imaging potential occurs chemically when the CMTF = 0, Einitial r-- Ethreshold, and physically when the MTF = 1.0, Emin = 0. As a result, acceptable patterning occurs when the MTF/CMTF ratio is greater than one. This ratio is a comparative, accept/reject test only; final nrocess optimization is done by monitoring the accepted resist/developer systems' performance on projected images. Optimum process latitude is predicted by determining focal tolerances at various mask sizing biases and by measuring linewidth necking over steps. This study demonstrates the dependence of the final print quality on the chemical con-trast. A method is examined for approximating minimum allowable chemical contrast required for adequately printing desired device design sizes. Then chemical contrast results for various metal-ion-free develop processes are shown. Next, the combined resist/developer/ optical performance is optimized by using focal tolerance and linewidth control over steps as process constraints. Finally, it is shown that focal tolerances are dependent on chemical contrast and that the focus budget is tunable.

  1. Jules Gonin. Pioneer of retinal detachment surgery.

    PubMed

    Wolfensberger, Thomas J

    2003-12-01

    Before the turn of the 20th century, eyes with a retinal detachment were considered doomed. Contrary to other branches of ophthalmology, such as cataract extraction, the surgical treatment of retinal detachment was still in its infancy, and the surgical success rates were less than five percent. From 1902 to 1921 Jules Gonin almost single handedly changed the landscape of retinal detachment surgery forever. He recognised that the retinal break was the cause--and not the consequence as it was largely believed at the time--of the retinal detachment, and that the treatment had at all costs to comprise the closure of the break by cauterisation. He named the procedure ignipuncture, as he cauterised the retina through the sclera with a very hot pointed instrument. Despite rigorously detailed clinical observations and increasing success rates, his discovery was not readily accepted and sometimes openly opposed by a large part of the ophthalmic establishment. It was not until 1929 that he received worldwide acclaim at the International Ophthalmological Congress in Amsterdam for his surgical technique. His legacy lives on in the eye hospital in Lausanne that bears his name, in the Gonin Medal awarded by the International Council of Ophthalmology every four years for the highest achievement in ophthalmology, and in a street named after him, the very street that he used to walk from his home to the hospital every day. PMID:14750617

  2. Current understanding of divertor detachment: experiments and modelling

    SciTech Connect

    Wischmeier, W; Groth, M; Kallenbach, A; Chankin, A; Coster, D; Dux, R; Herrmann, A; Muller, H; Pugno, R; Reiter, D; Scarabosio, A; Watkins, J; Team, T D; Team, A U

    2008-05-23

    A qualitative as well as quantitative evaluation of experimentally observed plasma parameters in the detached regime proves to be difficult for several tokamaks. A series of ohmic discharges have been performed in ASDEX Upgrade and DIII-D at similar as possible plasma parameters and at different line averaged densities, {bar n}{sub e}. The experimental data represent a set of well diagnosed discharges against which numerical simulations are compared. For the numerical modeling the fluid-code B2.5 coupled to the Monte Carlo neutrals transport code EIRENE is used. Only the combined enhancement of effects, such as geometry, drift terms, neutral conductance, increased radial transport and divertor target composition, explains a significant fraction of the experimentally observed asymmetries of the ion fluxes as a function of {bar n}{sub e} to the inner and outer target plates in ASDEX Upgrade. The relative importance of the mechanisms leading to detachment are different in DIII-D and ASDEX Upgrade.

  3. Two-stage Uplift of Granite-Gneiss-Migmatite Complex (GGMC) of Çataldaǧ Core Complex (Western Anatolia, Turkey): the role of detachment faults on uplift processes

    NASA Astrophysics Data System (ADS)

    Kamaci, Omer; Altunkaynak, Safak

    2016-04-01

    The most recently identified core complex of western Anatolia (Turkey), the Çataldaǧ Core Complex (ÇCC) consists of a granite-gneiss-migmatite complex (GGMC) representing deep crustal rocks of NW Turkey and a shallow level granodioritic body (ÇG: Çataldaǧ granodiorite). The GGMC is Latest Eocene-Early Oligocene and ÇG is Early Miocene in age, and both were exhumed in the footwall of the Çataldaǧ Detachment Fault Zone (ÇDFZ) in the Early Miocene. On the basis of correlation of age data and the closure temperatures of zircon, monazite, muscovite, biotite and K-feldspar, the T-time history of GGMC reveals that GGMC has experienced at least two stages of cooling and uplift, from 33.8 to 30.1 Ma and 21.3 to 20.7 Ma. In stage I, from 33.8 to 30.1 Ma, the cooling rate of GGMC was relatively slow (35°C/my) however cooling rate increase dramatically to ≥500°C/my in stage II between 21.3 and 20.7 Ma. T-time history also indicate that GGMC was elevated to the final location in at least 8-13 My according to the monazite and zircon and mica ages obtained from the same rock. Rapid slab rollback at the Hellenic trench at ca. 23 Ma may have increased extension rates leading to the development of detachment faults (i.e. ÇDFZ), core complexes and associated syn-extensional granitoids in Western Anatolia and the Aegean extensional province.

  4. Solar Ion Processing of Itokawa Grains: Reconciling Model Predictions with Sample Observations

    NASA Technical Reports Server (NTRS)

    Christoffersen, Roy; Keller, L. P.

    2014-01-01

    Analytical TEM observations of Itokawa grains reported to date show complex solar wind ion processing effects in the outer 30-100 nm of pyroxene and olivine grains. The effects include loss of long-range structural order, formation of isolated interval cavities or "bubbles", and other nanoscale compositional/microstructural variations. None of the effects so far described have, however, included complete ion-induced amorphization. To link the array of observed relationships to grain surface exposure times, we have adapted our previous numerical model for progressive solar ion processing effects in lunar regolith grains to the Itokawa samples. The model uses SRIM ion collision damage and implantation calculations within a framework of a constant-deposited-energy model for amorphization. Inputs include experimentally-measured amorphization fluences, a Pi steradian variable ion incidence geometry required for a rotating asteroid, and a numerical flux-versus-velocity solar wind spectrum.

  5. Syneresis and delayed detachment in agar plates.

    PubMed

    Divoux, Thibaut; Mao, Bosi; Snabre, Patrick

    2015-05-14

    Biogels made of crosslinked polymers such as proteins or polysaccharides behave as porous soft solids and store large amounts of solvent. These gels undergo spontaneous aging, called syneresis, which consists of the shrinkage of the gel matrix and the progressive expulsion of solvent. As a result, a biogel originally casted in a container often loses contact with the container sidewalls, and the detachment time is difficult to anticipate a priori, since it may occur over variable time spans (from hours to days). Here we report on syneresis phenomena in agar plates, which consist of Petri dishes filled with a gel mainly composed of agar. Direct observations and speckle pattern correlation analysis allow us to rationalize the delayed detachment of the gel from the sidewall of the Petri dish. The detachment time t* is surprisingly not controlled by the mass loss as one would intuitively expect. Instead, t* is strongly correlated to the gel minimum thickness emin measured along the sidewall of the plate, and increases as a robust function of emin, independently of the prior mass-loss history. Time-resolved correlation spectroscopy atypically applied to such weakly diffusive media gives access to the local thinning rate of the gel. This technique also allows us to detect the gel micro-displacements that are triggered by water evaporation prior to the detachment, and even to anticipate the latter from a few hours. Our work provides observables to predict the detachment time of agar gels in dishes, and highlights the relevance of speckle pattern correlation analysis for the quantitative investigation of the syneresis dynamics in biopolymer gels. PMID:25812667

  6. Heavy-ion induced genetic changes and evolution processes

    NASA Technical Reports Server (NTRS)

    Yang, C. H.; Craise, L. M.; Durante, M.; Mei, M.

    1994-01-01

    On Moon and Mars, there will be more galactic cosmic rays and higher radiation doses than on Earth. Our experimental studies showed that heavy ion radiation can effectively cause mutation and chromosome aberrations and that high Linear Energy Transfer (LET) heavy-ion induced mutants can be irreversible. Chromosome translocations and deletions are common in cells irradiated by heavy particles, and ionizing radiations are effective in causing hyperploidy. The importance of the genetic changes in the evolution of life is an interesting question. Through evolution, there is an increase of DNA content in cells from lower forms of life to higher organisms. The DNA content, however, reached a plateau in vertebrates. By increasing DNA content, there can be an increase of information in the cell. For a given DNA content, the quality of information can be changed by rearranging the DNA. Because radiation can cause hyperploidy, an increase of DNA content in cells, and can induce DNA rearrangement, it is likely that the evolution of life on Mars will be effected by its radiation environment. A simple analysis shows that the radiation level on Mars may cause a mutation frequency comparable to that of the spontaneous mutation rate on Earth. To the extent that mutation plays a role in adaptation, radiation alone on Mars may thus provide sufficient mutation for the evolution of life.

  7. Threshold processes of sodium ion emission from NaAu surface alloy

    NASA Astrophysics Data System (ADS)

    Knat'ko, M. V.; Lapushkin, M. N.

    2015-04-01

    We have studied threshold processes of Na+ ion emission from a semiconductor Na x Au y film formed on the surface of a gold substrate. In contrast to the classical notions of threshold processes involved in the surface ionization of alkali metal ions from heated metal surfaces, the diffusion exchange of atomic species between the surface and volume of the Na x Au y film ensures stable emission of Na+ ions from the substrate in the region of threshold temperatures. A diffusion mechanism of self-regulation of the surface coverage of alkali metal in the Na x Au y film is proposed.

  8. Process for the displacement of cyanide ions from metal-cyanide complexes

    DOEpatents

    Smith, Barbara F.; Robinson, Thomas W.

    1997-01-01

    The present invention relates to water-soluble polymers and the use of such water-soluble polymers in a process for the displacement of the cyanide ions from the metal ions within metal-cyanide complexes. The process waste streams can include metal-cyanide containing electroplating waste streams, mining leach waste streams, mineral processing waste streams, and related metal-cyanide containing waste streams. The metal ions of interest are metals that give very strong complexes with cyanide, mostly iron, nickel, and copper. The physical separation of the water-soluble polymer-metal complex from the cyanide ions can be accomplished through the use of ultrafiltration. Once the metal-cyanide complex is disrupted, the freed cyanide ions can be recovered for reuse or destroyed using available oxidative processes rendering the cyanide nonhazardous. The metal ions are released from the polymer, using dilute acid, metal ion oxidation state adjustment, or competing chelating agents, and collected and recovered or disposed of by appropriate waste management techniques. The water-soluble polymer can then be recycled. Preferred water-soluble polymers include polyethyleneimine and polyethyleneimine having a catechol or hydroxamate group.

  9. Dynamics of Faceted Nanoparticles Formation in a Crystalline Matrix During Ion Implantation Processing.

    PubMed

    Li, Kun-Dar

    2016-02-01

    The faceted nanoparticle synthesized by ion implantation, such as Zn, Cu or Ag nanoparticles, is one of the promising materials for the next generation of optical devices. To understand and better control the manufacturing processes of ion implantation, a theoretical model is applied to investigate the formation and evolution of faceted nanoparticles under various experimental conditions of implantation processing. In this study, the mechanisms of the anisotropic interfacial energy and kinetics with different ion distributions are taken into consideration to demonstrate the role of the crystallographic symmetry, ion energy and temperature on the faceted nanoparticles formation in a crystalline matrix. As presented in the numerical results, the morphological shape of the nanoparticles is mainly affected by the crystallographic symmetry, while the distribution of the precipitates is principally determined by the ion energy. For the condition of high-temperature implantation, a high mobility of ions causes the characteristic length of nanostructures to increase and creates a coarsening morphology of nanoparticles. It is attributed to a longer diffusion distance during the nucleation and growth processes. This model can be widely used for the predictions of the nanostructures formation with various ion implantation processes. PMID:27433726

  10. Current and Prospective Li-Ion Battery Recycling and Recovery Processes

    NASA Astrophysics Data System (ADS)

    Heelan, Joseph; Gratz, Eric; Zheng, Zhangfeng; Wang, Qiang; Chen, Mengyuan; Apelian, Diran; Wang, Yan

    2016-06-01

    The lithium ion (Li-ion) battery industry has been growing exponentially since its initial inception in the late 20th century. As battery materials evolve, the applications for Li-ion batteries have become even more diverse. To date, the main source of Li-ion battery use varies from consumer portable electronics to electric/hybrid electric vehicles. However, even with the continued rise of Li-ion battery development and commercialization, the recycling industry is lagging; approximately 95% of Li-ion batteries are landfilled instead of recycled upon reaching end of life. Industrialized recycling processes are limited and only capable of recovering secondary raw materials, not suitable for direct reuse in new batteries. Most technologies are also reliant on high concentrations of cobalt to be profitable, and intense battery sortation is necessary prior to processing. For this reason, it is critical that a new recycling process be commercialized that is capable of recovering more valuable materials at a higher efficiency. A new technology has been developed by the researchers at Worcester Polytechnic Institute which is capable of recovering LiNi x Mn y Co z O2 cathode material from a hydrometallurgical process, making the recycling system as a whole more economically viable. By implementing a flexible recycling system that is closed-loop, recycling of Li-ion batteries will become more prevalent saving millions of pounds of batteries from entering the waste stream each year.

  11. Risk factors of rhegmatogenous retinal detachment associated with choroidal detachment in Chinese patients

    PubMed Central

    Gu, Yong-Hao; Ke, Gen-Jie; Wang, Lin; Gu, Qi-Hong; Zhou, En-Liang; Pan, Hong-Biao; Wang, Shi-Ying

    2016-01-01

    AIM To comprehensively analyze the risk factors of rhegmatogenous retinal detachment (RRD) associated with choroidal detachment (CD). METHODS A total of 265 eyes of 265 consecutive cases of RRD were retrospectively analyzed. All patients had systemic and ophthalmologic examination. CD was diagnosed by indirect ophthalmoscopy, B-scan ultrasonography, and ultrasound biomicroscope (UBM). Each parameter was compared between patients of RRD and rhegmatogenous retinal detachment associated with choroidal detachment (RRDCD). Logistic regression analysis was used to determine the independent risk factors of CD. RESULTS There were 52 eyes (19.62%) with CD. Pseudophakia was more commonly seen in RRDCD (21.15% vs 6.10%, P=0.002). Intraocular pressure (IOP) was lower (8.60±3.62 vs 12.96±3.55, P<0.001), best-corrected visual acuity was worse [3.00 (2.00 to 3.00) vs 1.92 (1.22 to 3.00), P=0.001], and refractive error was more myopic [-4 (-9 to -2) vs -2 (-6 to 0), P=0.007] in RRDCD. Eyes with RRDCD had larger extent of retinal detachment (P=0.007). In RRDCD, 34.62% of eyes presented with multiple holes (P=0.044) and 25.00% with macular holes (P=0.012), compared with 20.66% and 14.08% in RRD. High myopia (P=0.039), low IOP (P=0.017), and larger extent of retinal detachment (P<0.001) were significant and independent risk factors for developing CD. CONCLUSION For CD in RRD, related factors include BCVA, IOP, lens status, refractive error, extent of retinal detachment, number of holes, and macular hole. Larger extent of retinal detachment, high myopia, and low IOP are significant and independent risk factors. PMID:27500106

  12. Quantum Information Processing with Ytterbium Ions and a Frequency Comb in a Surface Trap

    NASA Astrophysics Data System (ADS)

    Mount, Emily; Baek, So-Young; Gaultney, Daniel; Crain, Stephen; Noek, Rachel; Maunz, Peter; Kim, Jungsang

    2012-06-01

    Microfabricated surface ion traps are one of the key components for building a trapped ion quantum information processor.These multi-segmented traps are fabricated using existing silicon processing technology and can provide the fields to store a chain of ions and shuttle ions within the trap structure. Using a surface trap microfabricated by Sandia National Laboratories [1] we trap individual Yb-171 ions and demonstrate fundamental quantum information processing primitives. Low light scatter from the trap and the use of photon arrival times during fluorescence state detection enables a state detection fidelity of 98%. High fidelity rotations of the hyperfine clock state qubit have been performed using a resonant microwave field. Furthermore, we have realized single qubit rotations using Raman transitions driven by a repetition-rate stabilized frequency comb, a prerequisite for realizing motional gates with frequency combs [2]. Microelectromechanical systems (MEMS) mirrors will be used to focus Raman laser beams on individual ions in a chain to perform single qubit gates. MEMS beam steering systems can easily be scaled to multiple beams to realize two-ion gates between arbitrary ions in the chain.[4pt] [1] D Stick et al., arXiv:1008.0990v2 2010[0pt] [2] D Hayes et al., PRL 104(14)2010

  13. Ion-Neutral Collisions in the Interstellar Medium: Wave Damping and Elimination of Collisionless Processes

    SciTech Connect

    Spangler, Steven R.; Savage, Allison H.; Redfield, Seth

    2011-09-21

    Most phases of the interstellar medium contain neutral atoms in addition to ions and electrons. This introduces differences in plasma physics processes in those media relative to the solar corona and the solar wind at a heliocentric distance of 1 astronomical unit. In this paper, we consider two well-diagnosed, partially-ionized interstellar plasmas. The first is the Warm Ionized Medium (WIM) which is probably the most extensive phase in terms of volume. The second is the gas of the Local Clouds of the Very Local Interstellar Medium (VLISM). Ion-neutral interactions seem to be important in both media. In the WIM, ion-neutral collisions are relatively rare, but sufficiently frequent to damp magnetohydrodynamic (MHD) waves (as well as propagating MHD eddies) within less than a parsec of the site of generation. This result raises interesting questions about the sources of turbulence in the WIM. In the case of the VLISM, the ion-neutral collision frequency is higher than that in the WIM, because the hydrogen is partially neutral rather than fully ionized. We present results showing that prominent features of coronal and solar wind turbulence seem to be absent in VLISM turbulence. For example, ion temperature does not depend on ion mass. This difference may be due to ion-neutral collisions, which distribute power from more effectively heated massive ions such as iron to other ion species and neutral atoms.

  14. Ion-Neutral Collisions in the Interstellar Medium: Wave Damping and Elimination of Collisionless Processes

    NASA Astrophysics Data System (ADS)

    Spangler, Steven R.; Savage, Allison H.; Redfield, Seth

    2011-09-01

    Most phases of the interstellar medium contain neutral atoms in addition to ions and electrons. This introduces differences in plasma physics processes in those media relative to the solar corona and the solar wind at a heliocentric distance of 1 astronomical unit. In this paper, we consider two well-diagnosed, partially-ionized interstellar plasmas. The first is the Warm Ionized Medium (WIM) which is probably the most extensive phase in terms of volume. The second is the gas of the Local Clouds of the Very Local Interstellar Medium (VLISM). Ion-neutral interactions seem to be important in both media. In the WIM, ion-neutral collisions are relatively rare, but sufficiently frequent to damp magnetohydrodynamic (MHD) waves (as well as propagating MHD eddies) within less than a parsec of the site of generation. This result raises interesting questions about the sources of turbulence in the WIM. In the case of the VLISM, the ion-neutral collision frequency is higher than that in the WIM, because the hydrogen is partially neutral rather than fully ionized. We present results showing that prominent features of coronal and solar wind turbulence seem to be absent in VLISM turbulence. For example, ion temperature does not depend on ion mass. This difference may be due to ion-neutral collisions, which distribute power from more effectively heated massive ions such as iron to other ion species and neutral atoms.

  15. Early Miocene mylonitization and detachment faulting, South Mountains, central Arizona

    SciTech Connect

    Reynolds, S.J.; Shafiqullah, M.; Damon, P.E.; DeWitt, E.

    1986-04-01

    The South Mountains of central Arizona are one of the geologically simplest metamorphic core complexes of the North American Cordillera. An early Miocene age of mylonitization is indicated by crosscutting relationships between mylonitic fabric and a composite pluton dated at 22-25 Ma by Rb-Sr, U-Th-Pb, and K-Ar techniques. The kinematic agreement and close temporal association of mylonitization and detachment faulting support models in which the two processes are related to an evolving crustal shear zone that accommodated mid-Tertiary continental extension. 19 references, 3 figures, 2 tables.

  16. Detached divertor operation in DIII-D helium plasmas

    SciTech Connect

    Hill, D. N., LLNL

    1998-05-01

    This paper presents results from operating helium plasmas in DIII-D in which helium gas puffing is used to reduce the peak divertor heat flux by factors of four or more. The threshold density for achieving these conditions is nearly the same as for deuterium plasmas, which is surprising given the fact that lack of chemical sputtering reduces the carbon concentration in the plasma by more than a factor of five. Spectroscopic analysis shows that helium becomes the primary radiation in these plasmas, which is possible because, unlike carbon, it is the primary species present. These plasmas differ from the usual partially detached divertor (PDD) plasmas in that there is no concomitant reduction in target plate ion flux with target plate heat flux in the scrape off later outside the separatrix.

  17. Flexible system for multiple plasma immersion ion implantation-deposition processes

    NASA Astrophysics Data System (ADS)

    Tian, Xiubo; Fu, Ricky K. Y.; Chu, Paul K.; Anders, Andre; Gong, Chunzhi; Yang, Shiqin

    2003-12-01

    Multiple plasma immersion ion implantation-deposition offers better flexibility compared to other thin film deposition techniques with regard to process optimization. The plasmas may be based on either cathodic arc plasmas (metal ions) or gas plasmas (gas ions) or both of them. Processing parameters such as pulsing frequency, pulse duration, bias voltage amplitude, and so on, that critically affect the film structure, internal stress, surface morphology, and other surface properties can be adjusted relatively easily to optimize the process. The plasma density can be readily controlled via the input power to obtain the desirable gas-to-metal ion ratios in the films. The high-voltage pulses can be applied to the samples within (in-duration mode), before (before-duration mode), or after (after-duration mode) the firing of the cathodic arcs. Consequently, dynamic ion beam assisted deposition processes incorporating various mixes of gas and metal ions can be achieved to yield thin films with the desirable properties. The immersion configuration provides to a certain degree the ability to treat components that are large and possess irregular geometries without resorting to complex sample manipulation or beam scanning. In this article we describe the hardware functions of such a system, voltage-current behavior to satisfy the needs of different processes, as well as typical experimental results.

  18. Physical Ion Sputtering At Glancing Angles As A Novel IC De-processing Technique

    SciTech Connect

    Vyatkin, A. F.; Zinenko, V. I.

    2011-01-07

    Failure analysis (de-processing) techniques are becoming more and more important in tackling integrated circuits (IC) process-related problems. Particularly, failure analysis of ICs requires opening and de-layering a chip in a layer by layer mode in order to find hidden defects. Selective chemical etching, reactive ion etching, plasma etching and chemical mechanical polishing or a combination of these techniques are traditionally used for de-processing of IC. In this work a novel technique which is physical ion sputtering at glancing incidence angles allowing precise information about possible reasons of IC failures occurring at different steps of IC processing is proposed.

  19. Modeling of detached and unsteady eutectic solidification

    NASA Astrophysics Data System (ADS)

    Popov, Dmitri I.

    Detached solidification provides a new possibility to grow crystals with improved quality. However, it has not been reproducible. The first part of this dissertation is dedicated to discussion of the mechanisms and conditions that would help to bring detached solidification from a space laboratory to a terrestrial factory. The possibility of a steady-state gap during detached solidification was proved by solving the mass transport and Navier-Stokes equations. A high contact angle of the melt with the ampoule wall, appreciable gas atmosphere, and a low freezing rate are needed to obtain detachment. Stability analysis showed that mass transfer of volatile species from the melt into the gap and heat transfer stabilize detached configuration. In vertical solidification on earth, a convex freezing interface was shown to provide enhanced transport of volatile species towards the gap, and, therefore, supports detachment. The influence of convection on eutectic microstructure selection has been a question for many years. Both experiment and theory have shown that buoyancy-driven convection alone is not enough to explain the difference in microstructure of earth- and space-grown eutectics. The second part of this dissertation is devoted to a study of the influence of temperature oscillations on microstructure selection. Two different models were chosen. The first, a sharp-interface model, was able to give a solution for the excess compositional undercooling for different leading conditions of both lamellar and rod eutectics. The limitation of this model is that it's not able to set the conditions for catastrophic morphological changes. Application of the principle of minimum entropy production to stationary eutectic growth predicts a decrease in eutectic spacing due to freezing rate oscillations. The second, a phase-field model, was developed for the evolution of the microstructure. This phase-field model correctly describes unsteady eutectic solidification, as well as

  20. Hard surfaced polymeric materials by ion beam processing

    SciTech Connect

    Simandl, R.F.; Rose, D.

    1996-09-27

    Initially, both General Motors and Lockheed Martin Energy Systems, Inc. were interested in altering the surface properties of polymers using ion beam technologies. Specifically, GM wished to treat the nylon that is used to encapsulate automotive assemblies so that it would be impervious to the alcohols and ethers used in present day blends of gasoline. Fuel oxygenates such as methanol can rapidly permeate the nylon encapsulant and tend to corrode the components within the assemblies. Once the CRADA was initiated, GM learned about the cleaning/decontamination expertise that was available at the Oak Ridge Y-12 Plant. Because GM was also interested in solving contamination issues related to these assemblies, GM worked with Lockheed Martin Energy Systems, Inc. to amend the CRADA to include such issues. Y-12 was eager to share its environmentally friendly, cleaning/decontamination expertise and also to expand upon its knowledge in this area. GM provided funds into the CRADA in order to address these contamination issues. Further on into the CRADA, GM put even more emphasis on the decontamination issues. This change in direction resulted because of rapid progress on the decontamination issues and, secondly, because GM changed its component material from nylon to the highly impervious polyphenylene sulfide.

  1. Receptor-mediated adhesion phenomena. Model studies with the Radical-Flow Detachment Assay.

    PubMed Central

    Cozens-Roberts, C; Quinn, J A; Lauffenberger, D A

    1990-01-01

    Receptor-mediated cell adhesion phenomena play a vital role in many physiological and biotechnology-related processes. To investigate the physical and chemical factors that influence the cell/surface interaction, we have used a radial flow device, a so-called Radial-Flow Detachment Assay (RFDA). The RFDA allows us to make direct observations of the detachment process under specified experimental conditions. In results reported here, we have studied the detachment of receptor-coated latex beads (prototype cells) from ligand-coated glass surfaces. The receptors and ligands used in this work are complementary antibodies. The beads enable us to examine several aspects of the adhesion process with particles having uniform properties that can be varied systematically. Advantages of the RFDA are many, especially direct observation of cell detachment over a range of shear stresses with quantitative measurement of the adhesive force. We focus our studies on the effects of ligand and receptor densities, along with the influence of pH and ionic strength of the medium. These data are analyzed with a mathematical model based on the theoretical framework of Bell, G. I. (1978. Science [Wash. DC]. 200:618-627) and Hammer, D. A. and D. A. Lauffenburger (1987. Biophys. J. 52:475-487). We demonstrate experimental validation of a theoretical expression for the critical shear stress for particle detachment, and show that it is consistent with reasonable estimates for the receptor-ligand bond affinity. Images FIGURE 2 PMID:2166596

  2. Retinoschisis transposition following a retinal detachment repair

    PubMed Central

    McVeigh, Katherine; Keller, Johannes; Haynes, Richard J.

    2015-01-01

    Objective: The authors have observed this phenomenon of translocation of the schisis cavity in a few previous cases and aim to report this unusual finding. Method: A patient with known superotemporal retinoschisis developed a distinctly separate inferotemporal retinal detachment in his left eye. This was repaired with a vitrectomy, cryotherapy and C2F6 tamponade under local anaesthetic. Following surgery, the retinoschisis was found in the inferonasal quadrant of the eye and remained stable as the gas dispersed. Result: We hypothesise that the tamponading agent compressed the viscous fluid within the area of schisis, displacing the area of schisis circumferentially. Conclusion: This case emphasises that as long as the retinal breaks are properly sealed, no intervention is required with the schisis during rhegmatogenous retinal detachment surgery.

  3. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    Detached crystal growth technique (dewetting) offers improvement in the quality of the grown crystals by preventing sticking to the walls of the crucible and thus reducing the possibility of parasitic nucleation and formation of lattice defects upon cooling. One of the factors relevant for the phenomena is the pressure differential across the meniscus at the crystal-melt interface. We investigated this effect experimentally. The growth took place in closed ampoules under the pressure of an inert gas (forming gas: 96% Ar + 4% H2). The pressure above the melt was adjustable and allowed for a control of the pressure difference between the top and bottom menisci. The crystals were characterized, particularly by taking profilometer measurements along the grown crystals surface. The effects of the experimental conditions on the detachment were compared with those predicted based on the theory of Duffar et al.

  4. Mechanism of bubble detachment from vibrating walls

    SciTech Connect

    Kim, Dongjun; Park, Jun Kwon Kang, Kwan Hyoung; Kang, In Seok

    2013-11-15

    We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

  5. Crystallization depth beneath an oceanic detachment fault (ODP Hole 923A, Mid-Atlantic Ridge)

    NASA Astrophysics Data System (ADS)

    Lissenberg, C. Johan; Rioux, Matthew; MacLeod, Christopher J.; Bowring, Samuel A.; Shimizu, Nobumichi

    2016-01-01

    Oceanic detachment faults are increasingly recognized as playing an integral role in the seafloor spreading process at slow and ultraslow spreading mid-ocean ridges, with significant consequences for the architecture of the oceanic lithosphere. Although melt supply is considered to play a critical control on the formation and evolution of oceanic detachments, much less well understood is how melts and faults interact and influence each other. Few direct constraints on the locus and depth of melt emplacement in the vicinity of detachments are available. Gabbros drilled in ODP Hole 923A near the intersection of the Mid-Atlantic Ridge and the Kane transform fault (23°N; the MARK area) represent magmas emplaced into the footwall of such a detachment fault and unroofed by it. We here present U-Pb zircon dates for these gabbros and associated diorite veins which, when combined with a tectonic reconstruction of the area, allow us to calculate the depths at which the melts crystallized. Th-corrected single zircon U-Pb dates from three samples range from 1.138 ± 0.062 to 1.213 ± 0.021 Ma. We find a crystallization depth of 6.4 +1.7/-1.3 km, and estimate that the melts parental to the gabbros were initially emplaced up to 1.5 km deeper, at <8 km below the seafloor. The tectonic reconstruction implies that the detachment fault responsible for the exposure of the sampled sequence likely crossed the ridge axis at depth, suggesting that melt emplacement into the footwall of oceanic detachment faults is an important process. The deep emplacement depth we find associated with "detachment mode" spreading at ˜1.2 Ma appears to be significantly greater than the depth of magma reservoirs during the current "magmatic mode" of spreading in the area, suggesting that the northern MARK segment preserves a recent switch between two temporally distinct modes of spreading with fundamentally different lithospheric architecture.

  6. Fast and slow ion diffusion processes in lithium ion pouch cells during cycling observed with fiber optic strain sensors

    NASA Astrophysics Data System (ADS)

    Sommer, Lars Wilko; Kiesel, Peter; Ganguli, Anurag; Lochbaum, Alexander; Saha, Bhaskar; Schwartz, Julian; Bae, Chang-Jun; Alamgir, Mohamed; Raghavan, Ajay

    2015-11-01

    Cell monitoring for safe capacity utilization while maximizing pack life and performance is a key requirement for effective battery management and encouraging their adoption for clean-energy technologies. A key cell failure mode is the build-up of residual electrode strain over time, which affects both cell performance and life. Our team has been exploring the use of fiber optic (FO) sensors as a new alternative for cell state monitoring. In this present study, various charge-cycling experiments were performed on Lithium-ion pouch cells with a particular class of FO sensors, fiber Bragg gratings (FBGs), that were externally attached to the cells. An overshooting of the volume change at high SOC that recovers during rest can be observed. This phenomenon originates from the interplay between a fast and a slow Li ion diffusion process, which leads to non-homogeneous intercalation of Li ions. This paper focuses on the strain relaxation processes that occur after switching from charge to no-load phases. The correlation of the excess volume and subsequent relaxation to SOC as well as temperature is discussed. The implications of being able to monitor this phenomenon to control battery utilization for long life are also discussed.

  7. Mesospheric electron detachment and LORE recovery times

    NASA Astrophysics Data System (ADS)

    Gordillo-Vazquez, Francisco J.; Haldoupis, Christos; Luque, Alejandro

    2015-04-01

    We present new results concerning the recovery times (> 10 minutes) of LOng Recovery Early VLF events (LORE) in the upper mesosphere connected to electromagnetic pulses (EMP) of large (> 250 kA km) charge moment change (CMC) ± CG (cloud to ground) lightning capable of producing elves or elve-sprite pairs (in the case of +CG parent lightning) [1], [2]. We have modeled two possible scenarios considering first the relaxation of slightly perturbed ambient electron densities (ne0 + Δne) without an impulsive ionization source and another scenario where the ambient electron density is considerably enhanced due to an impulsive ionization source (the lightning EMP). The full non-equilibrium kinetic and 2D EMP modelling of the perturbed mesosphere in the 76 km - 92 km range during LORE occurring conditions indicates that the electron density relaxation time (defined as the time the perturbed electron density, Δne, takes to decay a factor 1/e of the way to the ambient electron density (ne0)) is critically controlled at each altitude by the relative importance of associative detachment (of O- by, respectively, O and CO and of O2- by O) with respect to electron loss mechanisms (mainly 3-body, 2-body attachment and electron-ion recombination at the highest altitudes). We found that the maximum electron density relaxation time (> 15000 s) occur between 80 km and 82 km while it decreases with increasing altitudes to 12000 s (at 85 km) and about 2000 s (at 92 km). However, LORES are presumably due to VLF scattering from electron density enhancements caused by lightning-induced EMPs in the uppermost D region ionosphere (85 - 92 km). Thus the observed VLF signal recoveries (LORE recovery times) should associate with the relaxation of the maximum enhanced electron densities produced by elves between 85 km and 92 km [3]. Finally, our results for the lowest altitudes considered (76 km and 77 km) are in good agreement with the recovery times (between 20 s and 120 s) of the typical

  8. Features of the processes of ion heating in polar boundary of the night auroral oval

    NASA Astrophysics Data System (ADS)

    Chugunin, Dmitriy; Lutsenko, Volt; Romantsova, Tatiana; Mogilevsky, Mikhail; Moiseenko, Irina

    Investigation of the processes of ion heating in polar boundary of the night auroral oval measured by INTERBALL-2 (Auroral probe) is presented. Measurements of particles and waves were made on altitude about 20000 км. Feature of the orbits was the satellite slid along auroral oval and stay long time in the auroral zone. It were cases chosen when the polar boundary moved and passed through satellite. Particular attention is given to ions heating at this border and to ion heating position in relation to polar boundary of particle precipitation.

  9. Energy Transfer Process of Eu3+ Ions Doped in Tellurite Glass

    NASA Astrophysics Data System (ADS)

    Hong, Tran Thi; Dung, Phan Tien; Quang, Vu Xuan

    2016-05-01

    Tellurite glass doped with different concentrations of Eu3+ ions has been prepared by the conventional melting process. Photoluminescence, Raman spectra, phonon side-band spectra, and Judd-Ofelt analysis were carried out. Some spectroscopic parameters were estimated to predict the luminescence efficiency of the materials. The energy transfer between the rare-earth ions was observed, and a model for its cross-relaxation was proposed and quantitatively estimated. The charged intrinsic defects in the form of nonbridging oxygen (NBO) were determined, and the energy transfer between NBO and rare-earth ions observed. The energy-transfer-induced Eu3+ photoluminescence enhancement in tellurite glass is studied.

  10. Separation of Molybdenum-Uranium by a Process Combining Ion Exchange Resin and Membranes

    NASA Astrophysics Data System (ADS)

    Lounis, A.; Setti, L.; Djennane, A.; Melikchi, R.

    The purpose of this study is to determine whether the electrodeionization with ion-exchange resin is suitable for removing uranium from a solution containing molybdenum. A hybrid process combining ion exchange (resins and membranes) using electric current. For this electroextraction process, the cation exchange resin is introduced into an electrodialysis cell and compressed between two cations exchange membranes. We have investigated a continuous electroextraction process. As important result we note that: The factor of selectivity,r, for molybdenum versus uranium is superior to 3; the concentration in radio active element (U3O8) is lower than 1.5 mg L-1 and small cell voltage is observed.