Optical storage device

A new holographic image storage device which uses four-wave mixing in two photorefractive crystals is described. Photorefractive crystals promise information storage densities on the order of 10(exp 9) to 10(exp 12) bits per cubic centimeter at real-time rates. Several studies in recent years have investigated the use of photorefractive crystals for storing holographic image information. However, all of the previous studies have focused on techniques for storing information in a single crystal. The disadvantage of using a single crystal is that the read process is destructive. Researchers have developed techniques for fixing the information in a crystal so that it may be read many times. However, when fixed, the information cannot be readily erased and overwritten with new information. It two photorefractive crystals are used, holographic image information may be stored dynamically. That is, the stored image information may be read out more than once, and it may be easily erased and overwritten with new image information

Quantitative non-destructive testing

The work undertaken during this period included two primary efforts. The first is a continuation of theoretical development from the previous year of models and data analyses for NDE using the Optical Thermal Infra-Red Measurement System (OPTITHIRMS) system, which involves heat injection with a laser and observation of the resulting thermal pattern with an infrared imaging system. The second is an investigation into the use of the thermoelastic effect as an effective tool for NDE. As in the past, the effort is aimed towards NDE techniques applicable to composite materials in structural applications. The theoretical development described produced several models of temperature patterns over several geometries and material types. Agreement between model data and temperature observations was obtained. A model study with one of these models investigated some fundamental difficulties with the proposed method (the primitive equation method) for obtaining diffusivity values in plates of thickness and supplied guidelines for avoiding these difficulties. A wide range of computing speeds was found among the various models, with a one-dimensional model based on Laplace's integral solution being both very fast and very accurate

Solar radiation and atmospheric absorption in the mm wave region Semiannual report, 1 Apr. - 30 Sep. 1968

Study of absorption and emission of millimeter wave

Application of remote sensing to study nearshore circulation

Immediate use of drogued buoy tracking was made when the Virginia State Highway Department requested assistance in selecting the best route for a new bridge-tunnel complex across the James River at Newport News. The result was that the Highway Department acted and chose a preferred route from several alternatives. It was also observed that the drogues did not follow the channel as predicted by the James River hydraulic model. This permitted telling the Navy why it is that part of their channel always silts up. The Hampton Roads Sanitation District asked help locate the best route and position of an ocean sewer outfall. Biological activities are focused primarily on delineating biological interaction between the marsh and continental shelf waters on Virginia's Eastern Shore. Information derived is helpful in categorizing the relative biological value of different marsh areas so that meaningful use and management decisions can be made concerning their eventual disposition

Prevalence of QoI resistance and mtDNA diversity in the Irish Zymoseptoria tritici population

peer-reviewedThe emergence and spread of Quinone outside Inhibitor (QoI) fungicide resistance in the Irish Zymoseptoria tritici population in the early 2000s had immediate impacts on the efficacy of the entire group of fungicides for the control of septoria tritici blotch. As a result, a dramatic reduction in the quantities applied to winter wheat occurred in the following seasons. Even in the absence of these fungicides, the frequency of the resistance allele, G143A in the pathogens mtDNA has remained exceptionally high (>97%), and as such, it can be anticipated that continued poor efficacy of current QoI fungicides will be observed. Amongst the isolates with G143A, differences in sensitivity to the QoI pyraclostrobin were observed in vitro. The addition of the alternative oxidase (AOX) inhibitor salicylhydroxamic acid increased sensitivity in these isolates, suggesting some continued impairment of respiration by the QoI fungicides, albeit weak. Interestingly, amongst those tested, the strains from a site with a high frequency of inserts in the MFS1 transporter gene known to enhance QoI efflux did not exhibit this increase in sensitivity. A total of 19 mtDNA haplotypes were detected amongst the 2017 strain collection. Phylogenetic analysis confirmed the suggestion of a common ancestry of all the haplotypes, even though three of the haplotypes contained at least one sensitive strain

Bicarbonate or Carbonate Processes for Coupling Carbon Dioxide Capture and Electrochemical Conversion

Designing a scalable system to capture CO₂ from the air and convert it into valuable chemicals, fuels, and materials could be transformational for mitigating climate change. Climate models predict that negative greenhouse gas emissions will be required by the year 2050 in order to stay below a 2 °C change in global temperature. The processes of CO₂ capture, CO₂ conversion, and finally product separation all require significant energy inputs; devising a system that simultaneously minimizes the energy required for all steps is an important challenge. To date, a variety of prototype or pilot-level CO₂ capture and/or conversion systems have been designed and built targeting the individual objectives of either capture or conversion. One approach has focused on CO₂ removal from the atmosphere and storage of pure pressurized CO₂. Other efforts have concentrated on CO₂ conversion processes, such as electrochemical reduction or fermentation. Only a few concepts or analyses have been developed for complete end-to-end processes that perform both CO₂ capture and transformation