Workshop on oiled seabird cleaning and rehabilitation : proceedings of a workshop held in Townsville, Australia, 26 February 1991

This report is a summary of the proceedings from the Oiled Seabird Cleaning and Rehabilitation Workshop, the first in Queensland to address this issue. It is hoped that more workshops will be held in the future.Table of Contents: Dr Wendy Craik, Seabird Cleaning and Rehabilitation in the Great Barrier Reef Marine Park 17; Mr Terry Walker, Seabird Distribution on the Great Barrier Reef 24; Dr Peter Dann and Dr Ros Jessop, The Effect of Oil on Birds 37; Ms Erna Walraven and Mr Larry Vogelnest, Emergency Care for Birds at Lake Liddell Oil Spill 44; Mr Peter Brookhouse, Management of Wildlife Operations 49; and Material Submitted: Dr Geoffrey Smith, Rescuing Oiled Seabirds 61

Workshop on the use of bioremediation for oil spill response in the Great Barrier Reef Region : proceedings of a workshop held in Townsville, Australia, 25 February 1991

The intensity of shipping within the Great Barrier Reef presents a very real threat to the’ Reef from oil spills. In response to this threat, the Great Barrier Reef Marine Park Authority and the Commonwealth Department of Transport and Communications have developed REEFPLAN, the marine pollution contingency plan for the Great Barrier Reef Region. As of 1 January 1991, the role of the Department of Transport and Communications under REEFPLAN has been taken over by the Australian Maritime Safety Authority.Table of Contents: Papers Presented: Dr Wendy Craik, Bioremediation in the Great Barrier Reef Marine Park 15; Dr Riehard Edgehill, Bioremediation - The Biological, Physical, and Chemical Bases 20; Dr Bruce Kelley and Mr Stuart Rhodes, Bioremediation of Industrial Wastes 26; Ms Randi Larson, Research into Bioremediation of Oil and Related Compounds in Australia 32; Prof. Paul Greenfield, Bioremediation Applications in the Great Barrier Reef Marine Park 41; Dr Alan Sheehy, Bioremediation of Oil Spills 45; Mr Locon Wall, The Exxon Valdez Oil Spill - Woodward-Clyde Consultants' Contributions to Bioremediation 48; Papers Submitted: American Society for Microbiology, Biodegradation of Oil in the Open Ocean 53; and Ms Rebecca Hoff Bioremediation for Oil Spills - Update 55

Copper vapor laser drilling of copper, iron, and titanium foils in atmospheric pressure air and argon

A copper vapor laser (511 and 578 nm) is used to drill submillimeter diameter holes in 0.025–0.127 mm thick foils of copper, iron, and titanium. Foils are machined in atmospheric pressure air and argon. The laser is repetitively pulsed at 10 kHz with a per pulse energy of 0.5 mJ giving an average power of 5 W at the sample surface for a pulse width of 40 ns. A p‐i‐n photodiode and a photomultiplier tube detector are connected to a digital‐display timing circuit that records the number of incident laser pulses used to drill through the sample. The number of pulses is converted to an average drilling time and can provide an estimate for the average laser energy used to drill the hole. Typical data for all three materials with a per‐pulse fluence of 0.7 J/cm2 ranged from 0.1 to 500 s to produce holes of ∼0.3 mm diameter. Drilling times decreased in some cases by an order of magnitude when machining in air. This is attributed to the increased laser absorption of the metal‐oxide layer formed in air and was especially noticeable with titanium. A continuous wave thermal model is used to compare experimental data as well as verify the thermal machining mechanism.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69638/2/RSINAK-64-11-3308-1.pd

Ionization dynamics of iron plumes generated by laser ablation versus a laser‐ablation‐assisted‐plasma discharge ion source

The ionization dynamics (iron ion and neutral atom absolute line densities) produced in the KrF excimer laser ablation of iron and a laser‐ablation‐assisted plasma discharge (LAAPD) ion source have been characterized by a new dye‐laser‐based resonant ultraviolet interferometry diagnostic. The ablated material is produced by focusing a KrF excimer laser (248 nm,<1 J, 40 ns) onto a solid iron target. The LAAPD ion source configuration employs an annular electrode in front of the grounded target. Simultaneous to the excimer laser striking the target, a three‐element, inductor–capacitor, pulse‐forming network is discharged across the electrode–target gap. Peak discharge parameters of 3600 V and 680 A yield a peak discharge power of 1.3 MW through the laser ablation plume. Iron neutral atom line densities are measured by tuning the dye laser near the 271.903 nm (a 5D–y 5P0) ground‐state and 273.358 nm (a 5F–w 5D0) excited‐state transitions while iron singly ionized line densities are measured using the 263.105 nm (a 6D–z 6D0) and 273.955 nm (a 4D–z 4D0) excited‐state transitions. The line density, expansion velocity, temperature, and number of each species have been characterized as a function of time for laser ablation and the LAAPD. Data analysis assuming a Boltzmann distribution yields the ionization ratio (ni/nn) and indicates that the laser ablation plume is substantially ionized. With application of the discharge, neutral iron atoms are depleted from the plume, while iron ions are created, resulting in a factor of ∼5 increase in the plume ionization ratio. Species temperatures range from 0.5 to 1.0 eV while ion line densities in excess of 1×1015 cm−2 have been measured, implying peak ion densities of ∼1×1015 cm−3. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70077/2/JAPIAU-79-5-2287-1.pd

Laser‐ablation‐assisted‐plasma discharges of aluminum in a transverse‐magnetic field

Laser‐ablation‐assisted‐plasma discharges (LAAPD) have been used to enhance the ionization of laser ablated aluminum metal. Ablation is accomplished by focusing a KrF excimer laser (248 nm, 40 ns, ≤0.4 J) on a solid aluminum target with a fluence of 4 J/cm2. Peak plasma discharge voltage is 1–4 kV and peak plasma current is 0.2–1 kA, while peak power is 0.1–1 MW. Gated emission spectroscopy is used to determine the charge states and the electronic temperatures within the plasma discharge. With unmagnetized discharge parameters of 3 kV and 760 A, the observed light emission is dominated by transitions from Al2+ ions indicating nearly complete ionization of the plume. From the emission spectra intensities, an Al2+ electronic temperature of 3.3 eV is determined. Emission spectra from unmagnetized LAAPD of 1.2 kV and 280 A show no visible Al2+ ion transitions indicating cooler plasma and a lower ionization state. Introducing a 620 G transverse magnetic field (at 1.2 kV, 280 A) enhances the ionization due to the increased electron confinement and leads to the observance of the Al2+ lines as seen with discharges of 3 kV and 760 A.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70075/2/APPLAB-65-5-531-1.pd

Effects of laser‐ablation target damage on particulate production investigated by laser scattering with deposited thin film and target analysis

Experiments have been carried out to correlate ablated particulate density and size to the number of KrF excimer laser (248 nm, 40 ns, <1.2 J) pulses incident on a single location of a pure solid aluminum target and to relate particulate production to target surface damage. An analysis of laser ablation deposited aluminum films on silicon substrates was used to determine the density of ablated particulate greater than 0.5 μm in diameter. For an undamaged target, the laser deposited particulate density was on the order of 8.6×105 cm−2 per 1000 shots. A damaged target (following 1000 laser pulses) produced a density on the order of 1.6×106 cm−2 per 1000 shots on the substrate. Dye laser optical scattering was also used to measure, in real time, the velocity of the particulate and the relative particulate density in the laser‐ablation plume versus target damage. Results indicated a rapid rise in the production of particulate as target damage was increased up to 3000 laser pulses; after this number of shots the density of particulate in the laser ablation plume saturated. A peak in the scattered light for each stage of target damage occurred 40 μs after the initial KrF laser pulse, translating to a velocity of about 100 m/s for the smaller particulate (<1 μm diameter). The later scattered signal, around 160 μs, was apparently due to the larger particulate (5–15 μm), traveling at a velocity of approximately 25 m/s. Particulate production is related to the formation of laser ablation‐induced cones on the damaged targets. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70140/2/APPLAB-68-23-3245-1.pd

Hot dense capsule implosion cores produced by z-pinch dynamic hohlraum radiation

Hot dense capsule implosions driven by z-pinch x-rays have been measured for the first time. A ~220 eV dynamic hohlraum imploded 1.7-2.1 mm diameter gas-filled CH capsules which absorbed up to ~20 kJ of x-rays. Argon tracer atom spectra were used to measure the Te~ 1keV electron temperature and the ne ~ 1-4 x10^23 cm-3 electron density. Spectra from multiple directions provide core symmetry estimates. Computer simulations agree well with the peak compression values of Te, ne, and symmetry, indicating reasonable understanding of the hohlraum and implosion physics.Comment: submitted to Phys. Rev. Let

Resonant‐holographic‐interferometry for absolute measurements of excimer laser‐ablated neutral‐atom plume line‐density profiles

Experiments have been performed to measure Al neutral atom absolute line‐density profiles using resonant‐holographic‐interferometry. The ablation source is a KrF excimer laser with a per‐pulse energy of about 0.8 J. Targets are either pure aluminum or Al2O3. Aluminum ground‐state neutral atom line‐densities are probed by a dye laser tuned near the 394.401 nm line. A double‐pulse interferometry technique is employed in which one pulse includes the laser ablation plume and a second pulse generates reference fringes on a holographic plate by rotating a mirror. Holograms are reconstructed to give interference fringes on film by using a helium‐neon laser. Interferograms of laser ablated Al metal give maximum Al neutral plume line‐densities in the range of 4‐10×104 cm−2. Aluminum neutral line‐densities from Al2O3 targets are as much as 10‐20 times larger than from Al metal targets. The sensitivity of this resonant diagnostic is 4 to 5 orders of magnitude higher than nonresonant neutral‐particle interferometry and may be adjusted by tuning the dye laser wavelength shift away from the resonance line. This diagnostic has been demonstrated in vacuum, gas (14 mTorr ‐ 35 Torr) and RF plasma (30 mTorr ‐ 1 Torr) environments. At higher gas pressures, the nonresonant gas‐dynamic fringe shift can be subtracted to give the resonant fringe shift and species density.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87415/2/421_1.pd

Laser diagnostic experiments on KrF laser ablation plasma‐plume dynamics relevant to manufacturing applications@f|

A brief review is given of the potential applications of laser ablation in the automotive and electronics manufacturing industries. Experiments are presented on KrF laser ablation of three materials relevant to manufacturing applications: aluminum metal vs aluminum–nitride (AlN) and alumina (Al2O3) ceramics. Plasma and neutral‐atom diagnostic data are presented from resonant‐holographic‐interferometry, dye‐laser‐resonance‐absorption photography, and HeNe laser deflection. Data show that plasma electron densities in excess of 1018 cm−3 exist in the ablation of AlN, with lower densities in Al and Al2O3. Aluminum neutral and ion expansion velocities are in the range of cm/μs. Ambipolar electric fields are estimated to be 5–50 V/cm.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71186/2/PHPAEN-1-5-1619-1.pd