Composition and Structural Studies of Strong Glow Discharge Polymer Coatings

OAK A271 COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS. An investigation of the chemical composition and structure of strong glow discharge (GDP) polymer shells made for cryogenic experiments at OMEGA is described. The investigation was carried out using combustion and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The strongest coatings were observed to have the lowest hydrogen content or hydrogen/carbon H/C ratio, whereas the weakest coatings had the highest hydrogen content or H/C ratio. Chemical composition results from combustion were used to complement FTIR analysis to determine the relative hydrogen content of as-fabricated coatings. Good agreement was observed between composition results obtained from combustion and FTIR analysis. FTIR analysis of coating structures showed the strongest coatings to have less terminal methyl groups and a more double bond or olefinic structure. Strong GDP coatings that were aged in air react more with oxygen and moisture than standard GDP coatings. In addition to a more olefinic structure, there may also be more free-radial sites present in strong GDP coatings, which leads to greater oxygen uptake

COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS

OAK A271 COMPOSITION AND STRUCTURAL STUDIES OF STRONG GLOW DISCHARGE POLYMER COATINGS. An investigation of the chemical composition and structure of strong glow discharge (GDP) polymer shells made for cryogenic experiments at OMEGA is described. The investigation was carried out using combustion and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The strongest coatings were observed to have the lowest hydrogen content or hydrogen/carbon H/C ratio, whereas the weakest coatings had the highest hydrogen content or H/C ratio. Chemical composition results from combustion were used to complement FTIR analysis to determine the relative hydrogen content of as-fabricated coatings. Good agreement was observed between composition results obtained from combustion and FTIR analysis. FTIR analysis of coating structures showed the strongest coatings to have less terminal methyl groups and a more double bond or olefinic structure. Strong GDP coatings that were aged in air react more with oxygen and moisture than standard GDP coatings. In addition to a more olefinic structure, there may also be more free-radial sites present in strong GDP coatings, which leads to greater oxygen uptake

Recent Progress in Fabrication of High-Strength Glow Discharge Polymer Shells by Optimization of Coating Parameters

OAK A271 RECENT PROGRESS IN FABRICATION OF HIGH-STRENGTH GLOW DISCHARGE POLYMER SHELLS BY OPTIMIZATION OF COATING PARAMETERS. In this paper, the authors report the progress they have made in fabrication of high-strength thin-walled glow discharge polymer (GDP) shells for cryogenic experiments at OMEGA. They have investigated a number of different parameters involved in making such shells. Optimization of hydrogen to hydrocarbon precursor flow has been observed to be critical in obtaining strong shells. They can routinely make high-strength shells of OMEGA size (900 {micro}m in diameter) with thicknesses in the range of 1.0 to 1.5 {micro}m. The permeabilities of these shells to various gases have been found to be as much as three times higher than those of lower strength shells. Run to run variability and other batch statistics are discussed

FABRICATION AND PROPERTIES OF OER COATED RESORCINOL-FORMALDEHYDE SHELLS FOR OMEGA EXPERIMENTS

OAK-B135 New high gain designs for direct drive ignition on NIF require foam shells. Scaled down versions of these designs are needed for near term experiments on the OMEGA laser facility at the Laboratory Laser Energetics (LLE). These shells need to be about 1 mm in diameter and 50-100 {micro}m wall thickness and densities of 100-250 mg/cc. In addition, a full density permeation seal needs to be deposited for retention of the fill gas at room temperature or the ice at cryogenic temperatures. They have fabricated such shells using Resorcinol-formaldehyde (R/F) as the selected foam material due to its transparency in the optical region. Extensive characterization of the wall uniformity of these shells has been performed. The foam shells have {approx} 5%-6% non-concentricities on the average. A full density permeation seal has been deposited on the R/F shells using two different techniques. In the first technique R/F shells are coated directly with plasma polymer to thicknesses of 3-4 {micro}m. In the second technique, R/F shells are coated with polyvinylphenol, using a chemical interfacial polymerization technique. Data on surface finish and gas retention for R/F shells coated by both methods are provided

An orifice shape-based reduced order model of patient-specific mitral valve regurgitation

Mitral valve regurgitation (MR) is one of the most prevalent valvular heart diseases. Its quantitative assessment is challenging but crucial for treatment decisions. Using computational fluid dynamics (CFD), we developed a reduced order model (ROM) describing the relationship between MR flow rates, transvalvular pressure differences, and the size and shape of the regurgitant valve orifice. Due to its low computational cost, this ROM could easily be implemented into clinical workflows to support the assessment of MR. We reconstructed mitral valves of 43 patients from 3D transesophageal echocardiographic images and estimated the 3D anatomic regurgitant orifice areas using a shrink-wrap algorithm. The orifice shapes were quantified with three dimensionless shape parameters. Steady-state CFD simulations in the reconstructed mitral valves were performed to analyse the relationship between the regurgitant orifice geometry and the regurgitant hemodynamics. Based on the results, three ROMs with increasing complexity were defined, all of which revealed very good agreement with CFD results with a mean bias below 3% for the MR flow rate. Classifying orifices into two shape groups and assigning group-specific flow coefficients in the ROM reduced the limit of agreement predicting regurgitant volumes from 9.0 ml to 5.7 ml at a mean regurgitant volume of 57 ml

Advances in Target Design for Heavy-Ion Fusion

Over the past few years, the emphasis in heavy ion target design has moved from the distributed radiator target to the 'hybrid' target because the hybrid target allows a larger beam focal spot than the distributed radiator ({approx} 5 mm radius rather than {approx} 2 mm radius). The larger spot relaxes some of the requirements on the driver, but introduces some new target physics issues. Most notable is the use of shine shields and shims in the hohlraum to achieve symmetry rather than achieving symmetry by beam placement. The shim is a thin layer of material placed on or near the capsule surface to block a small amount of excess radiation. While we have been developing this technique for the heavy ion hybrid target, the technique can be used in any indirect drive target. We have begun testing the concept of a shim to improve symmetry using a double-ended z-pinch hohlraum on the Sandia Z-machine. Experiments using shimmed thin wall capsules have shown that we can reverse the sign of a P{sub 2} asymmetry and significantly reduce the size of a P{sub 4} asymmetry. These initial experiments demonstrate the concept of a shim as another method for controlling early time asymmetries in ICF capsules

An Overview of Science Education and Outreach Activities at the Princeton Plasma Physics Laboratory

The U. S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) has an energetic science education program and outreach effort. This overview describes the components of the programs and evaluates the changes that have occurred in this effort during the last several years. Efforts have been expanded to reach more students, as well as the public in general. The primary goal is to inform the public regarding the fusion and plasma research at PPPL and to excite students so that they can appreciate science and technology. A student's interest in science can be raised by tours, summer research experiences, in-classroom presentations, plasma expos, teacher workshops and web-based materials. The ultimate result of this effort is a better-informed public, as well as an increase in the number of women and minorities who choose science as a vocation. Measuring the results is difficult, but current metrics are reviewed. The science education and outreach programs are supported by a de dicated core group of individuals and supplemented by other members of the PPPL staff and consultants who perform various outreach and educational activities

Modelling the hemodynamics of coronary ischemia

Acting upon clinical patient data, acquired in the pathway of percutaneous intervention, we deploy hierarchical, multi-stage, data-handling protocols and interacting low- and high-order mathematical models (chamber elastance, state-space system and CFD models), to establish and then validate a framework to quantify the burden of ischaemia. Our core tool is a compartmental, zero-dimensional model of the coupled circulation with four heart chambers, systemic and pulmonary circulations and an optimally adapted windkessel model of the coronary arteries that reflects the diastolic dominance of coronary flow. We guide the parallel development of protocols and models by appealing to foundational physiological principles of cardiac energetics and a parameterisation (stenotic Bernoulli resistance and micro-vascular resistance) of patients’ coronary flow. We validate our process first with results which substantiate our protocols and, second, we demonstrate good correspondence between model operation and patient data. We conclude that our core model is capable of representing (patho)physiological states and discuss how it can potentially be deployed, on clinical data, to provide a quantitative assessment of the impact, on the individual, of coronary artery disease