459 research outputs found
Photoexcitation of lasers and chemical reactions for NASA missions: A theoretical study
The possibility of obtaining CW laser oscillation by optical pumping in the infrared at an elevated gas pressure is reviewed. A specific example utilizing a mixture of CO and NO gases is included. The gas pressures considered are in excess of several atmospheres. Laser frequency tuning over a broad region becomes possible at such elevated gas pressures due to collisional broadening of the amplifying transitions. The prior-rate and surprisal analysis are applied to obtain detailed VV and VT rates for CO and NO molecules and the transfer rates in a CO-NO gas mixture. The analysis is capable of giving temperature dependence of the rate constants. Computer estimates of the rates are presented for vibrational levels up to v = 50. The results show that in the high-lying vibrational states the VV transfer rates with Delta nu = 2 become appreciable
Development of tunable high pressure CO2 laser for lidar measurements of pollutants and wind velocities
The problem of laser energy extraction at a tunable monochromatic frequency from an energetic high pressure CO2 pulsed laser plasma, for application to remote sensing of atmospheric pollutants by Differential Absorption Lidar (DIAL) and of wind velocities by Doppler Lidar, was investigated. The energy extraction principle analyzed is based on transient injection locking (TIL) at a tunable frequency. Several critical experiments for high gain power amplification by TIL are presented
Electronic and optical properties of 5-AVA-functionalized BN nanoclusters: A DFT study
We carried out detailed density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations upon 5-aminolevulinic acid-functionalized B12N12 and B16N16 nanoclusters with the B3LYP, B3PW91, and PBE methods using the 6-311+G∗∗ basis set. The calculated adsorption energies of 5-aminolevulinic acid with the BN nanoclusters were evaluated at T = 298.15 and 311.15 K in the gaseous and aqueous environments with the B3LYP, B3PW91, and PBE methods. Our results showed that the adsorption of the 5-AVA molecule (NH2 group) with B12N12 is more favorable than-with the B16N16 nanocluster in the gas and solvent phases. It is anticipated that a 5-aminolevulinic acid (5-AVA) drug incorporating BN clusters could find application in drug delivery systems and in biomedical devices. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016
Vibrational relaxation measurements in CO2 USING an induced fluorescence technique
Vibrational relaxation measurements in carbon dioxide using induced infrared fluorescence techniqu
Survey on enrichment of Artemia urmiana nauplii with oxolinic acid and determination of its accumulation rate in different dosages and times
The nauplii of Artemia urmiana was enriched with oxolinic acid and the accumulation rate of this antibacterial drug in different times and dosages was determined. The nauplii which were hatched out of cysts from Urmia Lake's Artemia were incubated in the antibiotic/ seawater suspension with dosages of 25, 50, 75 and 100mg/l of oxolinic acid, in intervals of 2, 4, 6 and 8 hours. All factors including salinity, pH, aeration, dosage and enrichment time were kept the same for all treatments. Each treatment was repeated three times. After enrichment, the concentration of oxolinic acid per sample was determined by high performance liquid chromatography (HPLC). One way ANOVA and Duncan's tests were implemented to analyze the data
Advanced Control of FACTS Devices for Improving Power Quality Regarding to Wind Farms
AbstractIn recent years, there has been a worldwide development in the utilization of wind farms. Because of enlarging wind generation, growing non-liner loads and competitive electricity markets the operation mechanism of power systems are facing some problems like voltage regulation, damping of power oscillation, etc. in shunt FACTS devices STATCOM and SVC have been identified as a good device and perfect compensators to solve these troubles. So control strategies for STATCOM are sequentially changing. The proposed paper is shown that the use of advanced control methods, such as the standard robust control method, in the control system of FACTS could improve their performance
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Forecasting Seasonal Habitat Connectivity in a Developing Landscape
Connectivity and wildlife corridors are often key components to successful conservation and management plans. Connectivity for wildlife is typically modeled in a static environment that reflects a single snapshot in time. However, it has been shown that, when compared with dynamic connectivity models, static models can underestimate connectivity and mask important population processes. Therefore, including dynamism in connectivity models is important if the goal is to predict functional connectivity. We incorporated four levels of dynamism (individual, daily, seasonal, and interannual) into an individual-based movement model for black bears (Ursus americanus) in Massachusetts, USA. We used future development projections to model movement into the year 2050. We summarized habitat connectivity over the 32-year simulation period as the number of simulated movement paths crossing each pixel in our study area. Our results predict black bears will further colonize the expanding part of their range in the state and move beyond this range towards the greater Boston metropolitan area. This information is useful to managers for predicting and addressing human–wildlife conflict and in targeting public education campaigns on bear awareness. Including dynamism in connectivity models can produce more realistic models and, when future projections are incorporated, can ensure the identification of areas that offer long-term functional connectivity for wildlife
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