Remote measurements of ozone, water vapor and liquid water content, and vertical profiles of temperature in the lower troposphere

Several advanced atmospheric remote sensing systems developed at the Jet Propulsion Laboratory were demonstrated under various field conditions to determine how useful they would be for general use by the California Air Resources Board and local air quality districts. One of the instruments reported on is the Laser Absorption Spectrometer (LAS). It has a pair of carbon dioxide lasers with a transmitter and receiver and can be flown in an aircraft to measure the column abundance of such gases as ozone. From an aircraft, it can be used to rapidly survey a large region. The LAS is usually operated from an aircraft, although it can also be used at a fixed location on the ground. Some tests were performed with the LAS to measure ozone over a 2-km horizontal path. Another system reported on is the Microwave Atmospheric Remote Sensing System (MARS). It is tuned to microwave emissions from water vapor, liquid water, and oxygen molecules (for atmospheric temperature). It can measure water vapor and liquid water in the line-of-sight, and can measure the vertical temperature profile

Adaptive Bayesian decision feedback equalizer for dispersive mobile radio channels

The paper investigates adaptive equalization of time dispersive mobile ratio fading channels and develops a robust high performance Bayesian decision feedback equalizer (DFE). The characteristics and implementation aspects of this Bayesian DFE are analyzed, and its performance is compared with those of the conventional symbol or fractional spaced DFE and the maximum likelihood sequence estimator (MLSE). In terms of computational complexity, the adaptive Bayesian DFE is slightly more complex than the conventional DFE but is much simpler than the adaptive MLSE. In terms of error rate in symbol detection, the adaptive Bayesian DFE outperforms the conventional DFE dramatically. Moreover, for severely fading multipath channels, the adaptive MLSE exhibits significant degradation from the theoretical optimal performance and becomes inferior to the adaptive Bayesian DFE

Using ACIS on the Chandra X-ray Observatory as a particle radiation monitor

The Advanced CCD Imaging Spectrometer (ACIS) is one of two focal-plane instruments on the Chandra X-ray Observatory. During initial radiation-belt passes, the exposed ACIS suffered significant radiation damage from trapped soft protons scattering off the x-ray telescope's mirrors. The primary effect of this damage was to increase the charge-transfer inefficiency (CTI) of the ACIS 8 front-illuminated CCDs. Subsequently, the Chandra team implemented procedures to remove the ACIS from the telescope's focus during high-radiation events: planned protection during radiation-belt transits; autonomous protection triggered by an on-board radiation monitor; and manual intervention based upon assessment of space-weather conditions. However, as Chandra's multilayer insulation ages, elevated temperatures have reduced the effectiveness of the on-board radiation monitor for autonomous protection. Here we investigate using the ACIS CCDs themselves as a radiation monitor. We explore the 10-year database to evaluate the CCDs' response to particle radiation and to compare this response with other radiation data and environment models.Comment: 10 pages, 5 figures. To appear in Proc. SPIE vol. 773

Digital micromirror devices for laser-based manufacturing

Digital Micromirror Devices (DMDs), containing arrays of around one million individually-controllable ~10µm square mirrors, provide an extremely cost-effective and practical method to modulate the spatial beam profile of a pulsed laser source for both additive and subtractive laser processing and printing. When demagnified by a factor of ~100 in one dimension (hence ~10,000 in area) a ~1mJ/cm2 laser pulse reflected from the mirrors on the DMD surface that are switched to the 'on' position, attains a fluence of ~10J/cm2 at the workpiece, which is more than sufficient to ablate most materials of interest to the laser-manufacturing community. More familiar in the context of high values of magnification by the laser projection industry, reversing the role to use them for equally high values of demagnification opens up a wealth of possibilities for ablation, multiphoton polymerization, security marking and fabrication of features that perhaps surprisingly can be well below the wavelength of the laser used. Of key relevance is that very high-resolution patterning can be achieved by a single laser pulse, and step-and-repeat processes, when combined with the refresh rates of the DMD pattern that are currently at the 30kHz level, open up the possibility of processing areas of up to 1cm2 per second with micron-scale resolution where each ~100µm x 100µm area patterned per pulse can display arbitrary pixelated content. We will discuss the application of DMD-baser laser processing to the following areas of interest to the laser-manufacturing community

SOME EFFECTS OF RICE QUALITY ON ROUGH RICE PRICES

Quality discounts and premiums for rough rice in Texas rice bid/acceptance markets are analyzed. The most important quality factors determining the value of rough rice are head yield and peck. A one percentage point reduction in peck damage raises the price received per hundredweight of rough rice by $.13 to$.68 across markets and years. Since peck damage can be reduced by controlling the rice stinkbug, evaluation of alternative methods for better control of this pest in Texas rice fields is needed.Demand and Price Analysis,