New infrared laser transitions in Ag II

We have observed seven infrared laser transitions when exciting a He discharge in a silver hollow cathode. To our knowledge, five of the seven laser transitions have not been reported previously in the literature.     

Uncertainties in the estimation of ACF-based texture in syntheticaperture radar image data

Spatial analysis of synthetic aperture radar (SAR) image data holds much promise for characterizing and discriminating environmental scene elements. The autocorrelation function (ACF) has been identified as a potentially useful spatial metric because it admits an analysis with conventional linear system theory. Recent models of spatial scattering suggest that ACF-based texture analysis of SAR image data is capable of discriminating between a variety of area extensive targets. The incorporation of texture in an image classification or segmentation system requires some understanding of the uncertainties in the texture estimates. In this paper, the authors introduce a particular ACF model and examine the errors associated with estimating its parameters from image measurements. They also conduct an analysis of two important classes of errors: imaging system errors and estimation errors. They found that as the proportion of raw signal used to create the image increases the effects of system errors rapidly degrade ACF performance. This has implications for operationally produced image products that do not use an autofocusing procedure. They also found that the agreement between theoretical and observed estimation errors is quite good, so that the scale of these errors may be accurately estimated during a spatial analysis of the image data. They found some residual bias that may be attributed to both the use of the ACF itself and to the way the ACF model was constructed     

Engineering better wheelchairs to enhance community participation.

With about 2.2 million Americans currently using wheeled mobility devices, wheelchairs are frequently provided to people with impaired mobility to provide accessibility to the community. Individuals with spinal cord injuries, arthritis, balance disorders, and other conditions or diseases are typical users of wheelchairs. However, secondary injuries and wheelchair-related accidents are risks introduced by wheelchairs. Research is underway to advance wheelchair design to prevent or accommodate secondary injuries related to propulsion and transfer biomechanics, while improving safe, functional performance and accessibility to the community. This paper summarizes research and development underway aimed at enhancing safety and optimizing wheelchair design.     

Monetization methods for evaluating investments in electricity system resilience to extreme weather and climate change

Extreme weather events and associated damages have been increasing and these trends are expected to continue. Actions are being taken to enhance electricity system resilience. However, the justification for capital investments on resilience requires utilities to justify that the economic benefits outweigh the costs. This paper reviews the types of resilience measures being analyzed in cost-benefit analyses and addresses opportunities for improvement in characterizing the benefits for investments that enhance the resilience of electricity systems.     

Optical receiver front end for optically powered smart dust

The ability to create and direct beams of light means that optical communications potentially offer a large power advantage over RF communications for sensor networks. This paper presents an optically powered receiver front end for wireless optical communications. A complete optical receiver front end including a photodetector, clock and Manchester data recovery circuits has been fabricated using the UMC 180 nm CMOS process. A novel modulation scheme is described that has been devised so that this front end can recover the clock and Manchester data from an optical beam. Experimental results show that the total current consumption of the optical receiver front end is as low as 18.8 nA for a 0.5 V supply when a 1 kbps Manchester data and 8 kHz clock signal are successfully recovered. This means that photodiodes on the same substrate as the front end circuits extract enough power from the communications beam to allow the front end to work at distances of up to 10 m from the transmitter. Copyright © 2013 John Wiley & Sons, Ltd.     

Illumination with solid state lighting technology

High-power light-emitting diodes (LEDs) have begun to differentiate themselves from their more common cousins the indicator LED. Today these LEDs are designed to generate 10-100 lm per LED with efficiencies that surpass incandescent and halogen bulbs. After a summary of the motivation for the development of the high-power LED and a look at the future markets, we describe the current state of high-power LED technology and the challenges that lay ahead for development of a true "solid state lamp." We demonstrate record performance and reliability for high-power colored and white LEDs and show results from the worlds first 100-plus lumen white LED lamp, the solid state equivalent of Thomas Edison's 20-W incandescent lightbulb approximately one century later     

Characteristics of pigments,modification, and their functionalities

Novel treatments of pigments with inorganic materials have tremendous industrial and commercial prospects. Specific treatment of pigment has a marked effect on its behavior during application. The treatment allows a broad modification of the surface characteristics of pigment particles which leads to improved functionalities. Surface modification of pigments is achieved via coating, polymerization with modifying reagent, treatment with derivatives or polymers, which alter either the optical, conductivity or dispersibility during processing and application. These and many other distinguishing factors that affect the characteristics of pigments such as the class, crystal structure, particle morphology, particle size, hiding power, pigment volume concentration, surface character, and surface treatment have been reviewed. Various organic pigments such as those from fungus and bacteria, and the various families of pigment types such as metallic pigment, light interference, and diffractive pigments which presents decorative quality such as leafing, nonleafing, pearlscent, and Fabry‐Perot effects on substrates have also been reviewed in addition to those from inorganic sources with emphasis on the structure and physiochemical modifications using metal and nonmetal Ions.     

Performance of Methanol Oxidation Catalysts with Varying Pt:Ru Ratio as a Function of Temperature

This paper describes the effects of varying the Pt to Ru ratio in carbon-supported catalysts for methanol oxidation as a function of temperature. Previously these effects were studied in isolation, but now it is shown that the composition of a given catalyst as a function of temperature is extremely important for its activity towards methanol oxidation. Platinum rich 3:2 atomic ratio catalysts perform better than a 1:1 catalyst at 25 °C, where only Pt is believed to be active towards methanol dehydrogenation, since this process is a highly thermally activated process on Ru sites. This result is reversed at 65 °C, where the 1:1 catalyst displays much higher currents across the entire range of polarization. This may result from methanol dehydrogenation occurring on both Ru and Pt sites at higher temperatures. At an intermediate temperature, 45 °C, the 3:2 catalyst is seen to perform better at lower current values, while the 1:1 catalyst is superior at higher current densities, with the crossover occurring at 62 A g^–1. As a consequence, when designing fuel cell catalysts, the composition of the catalyst employed should be tailored with respect to the exact operating conditions, in order to promote optimum fuel cell performance.     

Lycopene from two food sources does not affect antioxidant or cholesterol status of middle-aged adults

Background

Epidemiological studies have reported associations between reduced cardiovascular disease and diets rich in tomato and/or lycopene. Intervention studies have shown that lycopene-containing foods may reduce cholesterol levels and lipid peroxidation, factors implicated in the initiation of cardiovascular disease. The objective of this study was to determine whether consumption of lycopene rich foods conferred cardiovascular protection to middle-aged adults as indicated by plasma lipid concentrations and measures of ex vivo antioxidants.

Methods

Ten healthy men and women consumed a low lycopene diet with no added lycopene (control treatment) or supplemented with watermelon or tomato juice each containing 20 mg lycopene. Subjects consumed each treatment for three weeks in a crossover design. Plasma, collected weekly was analyzed for total cholesterol, high density lipoprotein cholesterol (HDL-C) and triglyceride concentrations and for the antioxidant biomarkers of malondialdehyde formation products (MDA), plasma glutathione peroxidase (GPX) and ferric reducing ability of plasma (FRAP). Data were analyzed using Proc Mixed Procedure and associations between antioxidant and lipid measures were identified by Pearson's product moment correlation analysis.

Results

Compared to the control diet, the lycopene-containing foods did not affect plasma lipid concentrations or antioxidant biomarkers. Women had higher total cholesterol, HDL-C and triglyceride concentrations than did the men. Total cholesterol was positively correlated to MDA and FRAP while HDL-C was positively correlated to MDA and GPX. GPX was negatively correlated to triglyceride concentration.

Conclusions

The inclusion of watermelon or tomato juice containing 20 mg lycopene did not affect plasma lipid concentrations or antioxidant status of healthy subjects. However, plasma cholesterol levels impacted the results of MDA and FRAP antioxidant tests.