Crude Oil Remote Sensing, Characterization and Cleaning with CW and Pulsed Lasers

For detection, identification and characterization of crude oil we combine several optical methods of remote sensing of crude oil films and emulsions (coherent fringe projection illumination (CFP), holographic in-line interferometry (HILI), and laser induced fluorescence). These methods allow the three-dimensional characterization of oil spills, important for practical applications. Combined methods of CFP and HILI are described in the frame of coherent superposition of partial interference patterns. It is shown, that in addition to detection/identification laser illumination in the green-blue region can also degrade oil slicks. Different types of surfaces contaminated by oil spills are tested: oil on the water, oil on the flat solid surfaces and oil on the curved surfaces of pipes. For the detection and monitoring of the laser-induced oil degradation in pipes, coherent fiber bundles were used. Both continuous-wave (CW) and pulsed lasers are tested using pump-probe schemes. This finding suggests that properly structured laser clean-up can be an alternative environmentally-friendly method of decontamination, as compared to the currently used chemical methods that are dangerous to environment

Volume Holographic Recording and Readout for 90-Deg Geometry

When a prerecorded cross-beam hologram is reconstructed (so-called edge-lit readout) with a uniform plane wave and a point source, the resulting exact solutions reveal Bessel-function-type diffracted beam profiles, which are fundamentally modified under weak propagational diffraction. The case of a profiled beam readout with propagational diffraction may be analyzed using a transfer function approach based on 2-D Laplace transforms. In a second series of investigations, dynamic readout from a cross-beam volume hologram recorded with two orthogonal uniform plane waves is considered for various dependences of the refractive index modulation with intensity. Typically, refractive index profiles that are proportional to the intensity (as in the case of Kerr-type media or photorefractives with predominantly photovoltaic effect) and to the derivative of the intensity (as in diffusion-dominated photorefractives) are considered. Two-dimensional nonlinear coupled equations are developed for the two (Bragg) orders for both cases. Closed form solutions are obtained for the first case, indicating only nonlinearly induced self and cross-phase coupling. A simple experiment involving simultaneous recording and readout using photorefractive lithium niobate crystal indicates beam profile distortion, which may be expected in such 90-deg geometries

Broadband Dynamic, Holographically Self-Recorded, and Static Hexagonal Scattering Patterns in Photorefractive KNbO3:Fe

We have observed and explained three types of hexagon pattern formation in photo refractive crystal KNb03:Fe. These are: Dynamic (laser induced) Semipermanent (holographically stored) Permanent (induced by a static domain grid) over a wide wavelength rang

Self-Enhancement of Dynamic Gratings in Photogalvanic Crystals

We have developed a compact closed-form solution of the band transport model for high-contrast gratings in photogalvanic crystals. Our solution predicts the effect of the photoconductivity and the electric field grating enhancement due to the photogalvanic effect. We predict a pronounced dependence of the steady-state photogalvanic current on the contrast of the interference pattern and an increase of holographic storage time due to the enhancement of the photoconductivity grating contrast. In the high contrast limit and a large photogalvanic effect the refractive index grating will be shifted from the position of the intensity modulation pattern, contrary to the usually adopted model of unshifted gratings

Heavy electrons: Electron droplets generated by photogalvanic and pyroelectric effects

Electron clusters, X-rays and nanosecond radio-frequency pulses are produced by 100 mW continuous-wave laser illuminating ferroelectric crystal of LiNbO_3. A long-living stable electron droplet with the size of about 100 mcm has freely moved with the velocity 0.5 cm/s in the air near the surface of the crystal experiencing the Earth gravitational field. The microscopic model of cluster stability, which is based on submicroscopic mechanics developed in the real physical space, is suggested. The role of a restraining force plays the inerton field, a substructure of the particles' matter waves, which a solitary one can elastically withstand the Coulomb repulsion of electrons. It is shown that electrons in the droplet are heavy electrons whose mass at least 1 million of times exceeds the rest mass of free electron. Application for X-ray imaging and lithography is discussed.Comment: 15 p., 3 fig

Rapid Laser-assisted Nanosizing Noble Silver Nanoparticles in Plant Extracts and Physiochemical Characterization

Abstract Production of silver nanoparticles (AgNP

Remote Detection of Oil Slicks at the Ocean Surface

The 2010 Deepwater Horizon (DWH) oil slick caused by the explosion of the Macondo well was the worst man-made disaster in the history of the Gulf of Mexico, and the largest marine spill in the history of the petroleum industry. We provide an overview of our efforts to monitor the extent of these slicks using automated algorithms for the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Synthetic Aperture Radar (SAR). We discuss the advantages and limitations of each of the methods in detection of oil from space, and suggest that the NIR bands may be the best option to monitor emulsified oil when using passive sensors. Additionally, we discuss current laboratory-based efforts to measure oil thickness via holographic interferometry, and propose this as an ideal technique for future remote sensing of oil.

A Unified Treatment of Radiation-Induced Photorefractive, Thermal, and Neutron Transmutation Gratings

We have reviewed different types of periodic structures (superlattices) induced by optical, infrared, and neutron irradiation. Both optical and electrical properties of these superlattices are analyzed, starting from the standard photorefractive model. New results on the thermoelectric and pyroelectric dynamic gratings are discussed in connection to the energy conversion and vibration sensing. For the neutron irradiation both real-time and static grating are analyzed, suggesting transmutation doping as a mechanism of recording

Green Synthesis of Silver Nanoparticles, Their Characterization, Application and Antibacterial Activity

Our research focused on the production, characterization and application of silver nanoparticles (AgNPs), which can be utilized in biomedical research and environmental cleaning applications. We used an environmentally friendly extracellular biosynthetic technique for the production of the AgNPs. The reducing agents used to produce the nanoparticles were from aqueous extracts made from the leaves of various plants. Synthesis of colloidal AgNPs was monitored by UV-Visible spectroscopy. The UV-Visible spectrum showed a peak between 417 and 425 nm corresponding to the Plasmon absorbance of the AgNPs. The characterization of the AgNPs such as their size and shape was performed by Atom Force Microscopy (AFM), and Transmission Electron Microscopy (TEM) techniques which indicated a size range of 3 to 15 nm. The anti-bacterial activity of AgNPs was investigated at concentrations between 2 and 15 ppm for Gram-negative and Gram-positive bacteria. Staphylococcus aureus and Kocuria rhizophila, Bacillus thuringiensis (Gram-positive organisms); Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium (Gram-negative organisms) were exposed to AgNPs using Bioscreen C. The results indicated that AgNPs at a concentration of 2 and 4 ppm, inhibited bacterial growth. Preliminary evaluation of cytotoxicity of biosynthesized silver nanoparticles was accomplished using the InQ™ Cell Research System instrument with HEK 293 cells. This investigation demonstrated that silver nanoparticles with a concentration of 2 ppm and 4 ppm were not toxic for human healthy cells, but inhibit bacterial growth

Remote Detection of Oil Slicks at the Ocean Surface

The 2010 Deepwater Horizon (DWH) oil slick caused by the explosion of the Macondo well was the worst man-made disaster in the history of the Gulf of Mexico, and the largest marine spill in the history of the petroleum industry. We provide an overview of our efforts to monitor the extent of these slicks using automated algorithms for the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Synthetic Aperture Radar (SAR). We discuss the advantages and limitations of each of the methods in detection of oil from space, and suggest that the NIR bands may be the best option to monitor emulsified oil when using passive sensors. Additionally, we discuss current laboratory-based efforts to measure oil thickness via holographic interferometry, and propose this as an ideal technique for future remote sensing of oil.