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

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At least 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Non-invasive airway health measurement using synchrotron x-ray microscopy of high refractive index glass microbeads

Cystic fibrosis (CF) is caused by a gene defect that compromises the ability of the mucociliary transit (MCT) system to clear the airways of debris and pathogens. To directly characterise airway health and the effects of treatments we have developed a synchrotron X-ray microscopy method that non-invasively measures the local rate and patterns of MCT behaviour. Although the nasal airways of CF mice exhibit the CF pathophysiology, there is evidence that nasal MCT is not altered in CF mice1. The aim of this experiment was to determine if our non-invasive local airway health assessment method could identify differences in nasal MCT rate between normal and CF mice, information that is potentially lost in bulk MCT measurements. Experiments were performed on the BL20XU beamline at the SPring-8 Synchrotron in Japan. Mice were anaesthetized, a small quantity of micron-sized marker particles were delivered to the nose, and images of the nasal airways were acquired for 15 minutes. The nasal airways were treated with hypertonic saline or mannitol to increase surface hydration and MCT. Custom software was used to locate and track particles and calculate individual and bulk MCT rates. No statistically significant differences in MCT rate were found between normal and CF mouse nasal airways or between treatments. However, we hope that the improved sensitivity provided by this technique will accelerate the ability to identify useful CF lung disease-modifying interventions in small animal models, and enhance the development and efficacy of proposed new therapies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Investigations on nonlinear absorption and nonlinear refraction of a new photonic crystal using Z-scan

A new photonic material, (2E)-1-(3-chlorophenyl)-3-(2,4-dichlorophenyl)prop-2-en-1-one (DCPP) was synthesized and crystallised at room temperature. The functional groups of synthesised material were confirmed using FT-IR. The third order nonlinear optical (NLO) properties were investigated using Z-scan technique with 5 ns Nd:YAG laser pulses operating at a wavelength of 532 nm. Linear absorption spectrum of DCPP crystals shows an optical transmittance window and a lower cutoff wavelength of absorption at 380 nm. The direct transition band gap energy was determined using Tauc’s plot. The melting point and thermal stability of the crystal have been investigated by thermo gravimetric analysis/differential thermal analysis (TGA/DTA). The Thermo gravimetric curve showed absence of any phase transition before melting point.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Gain and refractive index dynamics in p-doped InAs quantum dash semiconductor optical amplifiers

The ultrafast carrier dynamics in a p-doped dash-in-a-well structure at 1.5 μm is experimentally investigated. An analysis of the timescales related to carrier relaxation and escape processes as well as the “dynamical” linewidth enhancement factor is presented and compared with results obtained from similar un-doped materials. Intentional p-doping of the active region results in an enhancement of the intermediate timescale of the gain dynamics associated with phonon-assisted electron capture and a reduction of the α-factor due to increased differential gain.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Effect of alpha and Gaussian refractive index profiles on the design of highly nonlinear optical fibre for efficient nonlinear optical signal processing

We propose an index profiled, highly nonlinear ultra-flattened dispersion fibre (HN-UFF) with appreciable values of fibre parameters such as dispersion, dispersion slope, effective area, nonlinearity, bending loss and splice loss. The designed fibre has normal zero flattened dispersion over S, C, L, U bands and extends up to 1.9857 μm. The maximum dispersion variation observed for this fibre is as low as 1.61 ps km{sup −1} nm{sup −1} over the 500-nm optical fibre transmission spectrum. This fibre also has two zero dispersion wavelengths at 1.487 and 1.9857 μm and the respective dispersion slopes are 0.02476 and 0.0068 ps nm{sup −2} km{sup −1}. The fibre has a very low ITU-T cutoff wavelength of 1.2613 μm and a virtuous nonlinear coefficient of 9.43 W{sup −1} km{sup −1}. The wide spectrum of zero flattened dispersion and a good nonlinear coefficient make the designed fibre very promising for different nonlinear optical signal processing applications. (fibre optics)

42 ENGINEERING↗
DOE OSTI2017

New laser technologies in ophthalmology for normalisation of intraocular pressure and correction of refraction

We present the results of recent studies that develop principally new approaches to solving the problem of visual impairment and provide the basis for new laser technologies in ophthalmology for the treatment of glaucoma, myopia and hypermetropia. The considered theoretical models and optical methods for detecting laser-induced structural changes in eye tissues pave the way to the invention of control systems with feedback, providing efficient and safe laser treatment. (laser medicine)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Seismic refraction tracks porosity generation and possible CO 2 production at depth under a headwater catchment

Significance To understand groundwater in weathered bedrock aquifers, we explore (bio)geochemical reactions using geophysical measurements. The result leads to a conceptual model for the three-dimensional distribution of geochemical alteration in the subsurface—well beyond the typical approach of inferring (bio)geochemical reactions in the subsurface from pits, boreholes, and outcrops. With this geophysical technique we discovered the prevalence of gas beneath the water table at this site. This geophysical viewing of the subsurface highlights patterns of water movement, reactions of clays, and microbial and abiotic gas-producing reactions recorded in the subsurface and thus illuminates storage, flow, and reactions of groundwater in bedrock systems. Protecting the groundwater resource beneath our feet will rely on such enhanced capacities to see into the subsurface.

58 GEOSCIENCES↗
DOE OSTI2017

Dispersion of the refractive index in high-k dielectrics

A brief review of the optical properties of oxide materials that are used at present as dielectrics in modern microelectronics is presented. Using spectral ellipsometry, dispersion dependencies for different materials are measured. A brief comparative analysis of different dielectric coatings is carried out. The results of our research will be useful in further studies of the properties of dielectrics, as well as in technologies that are employed in the development of new semiconductor instruments and devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS2002

A study of the refractivity bias in occultation retrievals using end-to-end simulations

Direct Methanol Fuel Cells in portable applications are expected to provide substantially higher energy density and longer operating times over advanced batteries. The time threshold of advantage of using a fuel cell instead of a battery is almost independent of the power level, and is determined by the power density of the fuel cell and its operating efficiency.

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