Automated nose fairing design - Honeycomb sandwich construction

Computer program for near optimum structural designs of ring stiffened honeycomb sandwich nose fairing

Theory of coherent active convolved illumination for superresolution enhancement

Recently an optical amplification process called the plasmon injection scheme was introduced as an effective solution to overcoming losses in metamaterials. Implementations with near-field imaging applications have indicated substantial performance enhancements even in the presence of noise. This powerful and versatile compensation technique, which has since been renamed to a more generalized active convolved illumination, offers new possibilities of improving the performance of many previously conceived metamaterial-based devices and conventional imaging systems. In this work, we present the first comprehensive mathematical breakdown of active convolved illumination for coherent imaging. Our analysis highlights the distinctive features of active convolved illumination, such as selective spectral amplification and correlations, and provides a rigorous understanding of the loss compensation process. These features are achieved by an auxiliary source coherently superimposed with the object field. The auxiliary source is designed to have three important properties. First, it is correlated with the object field. Second, it is defined over a finite spectral bandwidth. Third, it is amplified over that selected bandwidth. We derive the variance for the image spectrum and show that utilizing the auxiliary source with the above properties can significantly improve the spectral signal-to-noise ratio and resolution limit. Besides enhanced superresolution imaging, the theory can be potentially generalized to the compensation of information or photon loss in a wide variety of coherent and incoherent linear systems including those, for example, in atmospheric imaging, time-domain spectroscopy, ${\cal PT}$ symmetric non-Hermitian photonics, and even quantum computing.Comment: revised, more details and references adde

Spectral mixture modeling: Further analysis of rock and soil types at the Viking Lander sites

A new image processing technique was applied to Viking Lander multispectral images. Spectral endmembers were defined that included soil, rock and shade. Mixtures of these endmembers were found to account for nearly all the spectral variance in a Viking Lander image

MSFC evaluation of the space fabrication demonstration system (beam builder)

The beam builder, designed and manufactured as a ground demonstration model, is a precursor to a machine for use in the space environment, transportable by the space shuttle. The beam builder has the capability to automatically fabricate triangular truss beams in low Earth orbit with a highly reliable machine that requires a minimum of in-space maintenance and repair. A performance assessment of the beam builder, which was fabricated from commercial hardware is given

Interpretation of AIS Images of Cuprite, Nevada Using Constraints of Spectral Mixtures

A technique is outlined that tests the hypothesis Airborne Imaging Spectrometer (AIS) image spectra are produced by mixtures of surface materials. This technique allows separation of AIS images into concentration images of spectral endmembers (e.g., surface materials causing spectral variation). Using a spectral reference library it was possible to uniquely identify these spectral endmembers with respect to the reference library and to calibrate the AIS images

Compositional variability of the Martian surface

Spectral reflectance data from Viking Landers and Orbiters and from telescopic observations were analyzed with the objective of isolating compositional information about the Martian surface and assessing compositional variability. Two approaches were used to calibrate the data to reflectance to permit direct comparisons with laboratory reference spectra of well characterized materials. In Viking Lander multispectral images (six spectral bands) most of the spectral variation is caused by changes in lighting geometry within individual scenes, from scene to scene, and over time. Lighting variations are both wavelength independent and wavelength dependent. By calibrating lander image radiance values to reflectance using spectral mixture analysis, the possible range of compositions was assessed with reference to a collection of laboratory samples, also resampled to the lander spectral bands. All spectra from the lander images studied plot (in six-space) within a planar triangle having at the apexes the respective spectra of tan basaltic palagonite, gray basalt, and shale. Within this plane all lander spectra fit as mixtures of these three endmembers. Reference spectra that plot outside of the triangle are unable to account for the spectral variation observed in the images

Active plasmon injection scheme for subdiffraction imaging with imperfect negative index flat lens

We present an active physical implementation of the recently introduced plasmon injection loss compensation scheme for Pendry's non-ideal negative index flat lens in the presence of realistic material losses and signal-dependent noise. In this active implementation, we propose to use a physically convolved external auxiliary source for signal amplification and suppression of the noise in the imaging system. In comparison with the previous passive implementations of the plasmon injection scheme for sub-diffraction limited imaging, where an inverse filter post-processing is used, the active implementation proposed here allows for deeper subwavelength imaging far beyond the passive post-processing scheme by extending the loss compensation to even higher spatial frequencies.Comment: 13 pages, 15 figure

Hyperbolic metamaterial as a tunable near-field spatial filter for the implementation of the active plasmon injection loss compensation scheme

We present how to physically realize the auxiliary source described in the recently introduced active plasmon injection loss compensation scheme for enhanced near-field superlensing. Particularly, we show that the characteristics of the auxiliary source described in the active plasmon injection scheme including tunable narrow-band and selective amplification via convolution can be realized by using a hyperbolic metamaterial functioning as a near-field spatial filter. Besides loss compensation, the proposed near-field spatial filter can be useful for real-time high resolution edge detection.Comment: 8 pages, 8 figure

Are primary care practitioners in Barbados following diabetes guidelines? - a chart audit with comparison between public and private care sectors

<p>Abstract</p> <p>Background</p> <p>Over 19% of the population ≥ 40 years of age in Barbados are diabetic. The quality of diabetes primary care is uncertain.</p> <p>Findings</p> <p>Charts of diabetic and hypertensive patients were randomly sampled at all public and 20 private sector primary care clinics. Charts of all diabetic patients ≥ 40 years of age were then selected. Processes of care, and quality targets for blood pressure (BP), fasting blood glucose (FBG) and glycosylated haemoglobin (HbA1c) were documented.</p> <p>252 charts of diabetic patients (125 public and 127 private) were audited. Patients had the following characteristics: mean age 64 years, female gender 61%, mean duration of diagnosis 9 years, and hypertension diagnosed 78%. Patients had an average of 4.7 clinic visits per year, 66% were prescribed metformin, 68% a sulphonylurea, 25% a statin, 21% insulin, 15% aspirin and 12% a glucosidase inhibitor. Public patients compared to private patients were more likely to be female (77% vs. 46%, p < 0.01); have a longer duration of diagnosis (11.4 vs. 6.6 years, p < 0.01), have more clinic visits per year (5.2 vs. 4.3, p < 0.01), and to be using insulin (28 vs. 15% p = 0.01). Over a 2 year period, the proportion of charts with the following recorded at least once was: BP 98%, weight 80%, FBG 76%, total cholesterol 72%, urine tested for albumin 66%, serum creatinine 62%, dietary advice 61%, exercise advice 49%, lipid profile 48%, foot examination 41%, HbA1c 33%, dietician referral 23%, retinal examination 18%, tobacco use 17%, body mass index 0%, and waist circumference 0%. Public patients were more likely to have recorded: weight (92% vs. 68%, p = < 0.01); tests for total cholesterol (78% vs. 65%, p = 0.02), albuminuria (72% vs. 59%, p = 0.03), serum creatinine (79% vs. 44%, p < 0.01), and foot examination (50% vs. 32%, p = < 0.01); dietician referral (37% vs. 8%, p < 0.01), and tobacco use (26% vs. 8%, p < 0.01). For those tested, the most recent BP was < 140/90 for 43%, HBA1c was < 7% for 28%, and FBG was < 6.7 mmol/L for 27%.</p> <p>Conclusions</p> <p>Interventions such as body mass assessment, lifestyle advice, screening for retinopathy, monitoring blood glucose control, and achieving BP and glycaemic targets need improvement.</p