Offshore field experiments with in-situ burning of oil: Emissions and burn efficiency

ABSTRACTTo better understand the microbial functional diversity changes with subsurface redox conditions duringin situuranium bioremediation, key functional genes were studied with GeoChip, a comprehensive functional gene microarray, in field experiments at a uranium mill tailings remedial action (UMTRA) site (Rifle, CO). The results indicated that functional microbial communities altered with a shift in the dominant metabolic process, as documented by hierarchical cluster and ordination analyses of all detected functional genes. The abundance ofdsrABgenes (dissimilatory sulfite reductase genes) and methane generation-relatedmcrgenes (methyl coenzyme M reductase coding genes) increased when redox conditions shifted from Fe-reducing to sulfate-reducing conditions. The cytochrome genes detected were primarily fromGeobactersp. and decreased with lower subsurface redox conditions. Statistical analysis of environmental parameters and functional genes indicated that acetate, U(VI), and redox potential (Eh) were the most significant geochemical variables linked to microbial functional gene structures, and changes in microbial functional diversity were strongly related to the dominant terminal electron-accepting process following acetate addition. The study indicates that the microbial functional genes clearly reflect thein situredox conditions and the dominant microbial processes, which in turn influence uranium bioreduction. Microbial functional genes thus could be very useful for tracking microbial community structure and dynamics during bioremediation.

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A High-Accuracy Multiwavelength Radiometer for In Situ Measurements in the Thermal Infrared. Part II: Behavior in Field Experiments

Journal of Atmospheric and Oceanic Technology ◽

10.1175/1520-0426(2003)20<1023:ahmrfi>2.0.co;2 ◽

2003 ◽

Vol 20 (7) ◽

pp. 1023-1033 ◽

Cited By ~ 21

Author(s):

Gérard Brogniez ◽

Christophe Pietras ◽

Michel Legrand ◽

Philippe Dubuisson ◽

Martial Haeffelin

Keyword(s):

Field Experiments ◽

Thermal Infrared ◽

High Accuracy ◽

In Situ Measurements

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Colonization of depopulated crinoids by symbionts: who comes from the bottom and who from the water column?

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315415000600 ◽

2015 ◽

Vol 95 (8) ◽

pp. 1607-1612 ◽

Cited By ~ 4

Author(s):

E.S. Mekhova ◽

P.Y. Dgebuadze ◽

V.N. Mikheev ◽

T.A. Britayev

Keyword(s):

Water Column ◽

Field Experiments ◽

Dispersal Ability ◽

Long Distance ◽

Sandy Substrate ◽

Limited Dispersal ◽

Set Up ◽

Almost All ◽

High Degree

Previous experiments with the comatulid Himerometra robustipinna (Carpenter, 1881) demonstrated intensive host-to-host migration processes for almost all symbiotic species both within host aggregations and among hosts separated by several metres. The aim of this study was to check the ability of symbionts to complete long-distance migrations, by means of two in situ experiments which depopulated the crinoid host. Two different sets of field experiments were set up: exposure of depopulated crinoids (set 1) on stony ‘islands’ isolated from native crinoid assemblages by sandy substrate, and (set 2) in cages suspended in the water column. Hosts from set 1 were exposed for 1, 2, 3 and 4 weeks to assess whether substrate has an influence on the symbionts' long-distance migrations. In set 2 cages were exposed for 10–11 days, aiming to check whether symbionts were able to disperse through the water column with currents. These experiments allow the conclusion that post-settled symbionts can actively migrate among their hosts. Symbionts are able to reach their hosts by employing two different ‘transport corridors’, by drifting or swimming in water column, and by moving on the bottom. Comparison of experimental results allows the division of symbionts into two conventional groups according to the dispersal ability of their post-settled stages: (1) species able to complete long-distance migrations, (2) species unable to migrate or having limited dispersal ability. The finding of the free-living shrimp Periclimenes diversipes Kemp, 1922 in set 2 raises the question about the factors that affect such a high degree of specialization of crinoid assemblages.

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THE SEPARATION OF REMANENT FROM INDUCED MAGNETISM IN SITU

Geophysics ◽

10.1190/1.1439810 ◽

1966 ◽

Vol 31 (4) ◽

pp. 779-796 ◽

Cited By ~ 19

Author(s):

N. E. Goldstein ◽

S. H. Ward

Keyword(s):

Magnetic Anomaly ◽

Field Experiments ◽

Magnetic Anomalies ◽

Static Field ◽

Observational Evidence ◽

Field Direction ◽

Dynamic Field ◽

In Situ Separation

Remanent and induced magnetism both contribute to static field magnetic anomalies whereas only induced magnetism contributes to dynamic field magnetic anomalies. The theory whereby this phenomenon may be used to advantage for in‐situ separation of remanent from induced magnetism is presented as a prelude to observational evidence confirming the phenomenon. Four field experiments on Western States magnetic anomalies prove that it is possible to predict whether or not a given static field magnetic anomaly is primarily due to remanent or to induced magnetism. The limitations of the method include variability of micropulsation field direction, ellipticity, and intensity.

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In situ study of volcanic ash resuspension using a portable wind tunnel.

10.5194/egusphere-egu2020-21556 ◽

2020 ◽

Author(s):

Jacopo Taddeucci ◽

Elisabetta del Bello ◽

Jonathan P Merrison ◽

Keld R Rasmussen ◽

Jens J Iversen ◽

...

Keyword(s):

Wind Speed ◽

Wind Tunnel ◽

High Speed ◽

Volcanic Ash ◽

Field Experiments ◽

Critical Parameters ◽

Test Bed ◽

High Definition ◽

Sustained Activity

<p>The resuspension of volcanic ash deposits by wind is a well-known source of hazard following explosive eruptions. Besides the mail control exerted by the local wind field, ash resuspension is also influenced by: 1) atmospheric humidity; 2) features of the deposit (grain size distribution, sedimentary structures, etc.), and 3) features of the substrate (i.e. moisture, roughness). Ash resuspension is modeled using numerical simulations, which however require physical characterization and identification of the critical parameters controlling ash resuspension. Wind tunnel studies on volcanic particles are very limited and restricted to laboratory parameterizations, with in-situ effects not been parameterized. We tested field experiments of volcanic ash resuspension developing a portable wind tunnel and deploying on proximal (3 km) ash deposits from the semi-sustained activity of Sakurajima volcano (Japan) and from distal (250 km ca.) ash deposits from the 2011 Cordon Caulle eruption (Chile). The wind tunnel is calibrated with both LDA and pitot tubes measurements. The device allows generating a controlled wind profile within a 110x12x12 cm test section, which is placed directly on an untouched test bed of naturally deposited ash. Two types of experiments were performed: 1) ramp up speed experiments, where the wind speed is increased until reaching the threshold friction speed on four different substrates; 2) constant speed experiments, where three wind speed values where kept for 20 minutes using the same substrate. The threshold friction speed is measured with a hot wire anemometer, and the movement of resuspended ash is detected by means of multiple high speed and high definition digital camcorders. In-situ measured threshold friction speeds are compared to 1) in situ observed episodes of resuspension driven by local winds and 2) laboratory determination of threshold friction speed in controlled environmental conditions, and using the same ash deposited homogeneously.</p><p>&#160;</p>

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In situ soft sediment nutrient enrichment: A unified approach to eutrophication field experiments

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2016.06.096 ◽

2016 ◽

Vol 111 (1-2) ◽

pp. 287-294 ◽

Cited By ~ 13

Author(s):

Emily J. Douglas ◽

Conrad A. Pilditch ◽

Laura V. Hines ◽

Casper Kraan ◽

Simon F. Thrush

Keyword(s):

Nutrient Enrichment ◽

Field Experiments ◽

Soft Sediment ◽

Unified Approach

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Corrosion of Ti99.8-Pd Under Gamma Irradiation in MgC12-Rich Brine

MRS Proceedings ◽

10.1557/proc-506-477 ◽

1997 ◽

Vol 506 ◽

Cited By ~ 2

Author(s):

E. Smailos ◽

D. Schild ◽

K. Gompper

Keyword(s):

Surface Layer ◽

Field Experiments ◽

Surface Films ◽

General Corrosion ◽

Experimental Conditions ◽

Test Conditions ◽

Strong Candidate ◽

Main Component ◽

Container Material

ABSTRACTThe combined influence of gamma radiation (10 Gy/h) and high temperature (150 °C) on the corrosion of the promising HLW container material Ti99.8-Pd was investigated in an MgCl2-rich brine, and the corrosion surface films formed were characterized by XPS. For comparison, specimens without irradiation were also examined.Under the test conditions used, the alloy Ti99.8-Pd is resistant to local corrosion and its general corrosion is negligible low. The thin corrosion films formed on the surface of unirradiated specimens and in the crevices of specimens exposed to radiation consist of TiO2. However, outside the crevices of irradiated specimens, a surface layer consisting of Mg (main component of the brine) and Si (impurity in the brine) oxide is built up over the TiO2 layer. Comparable TiO2 layer thicknesses (30 - 65 nm, depending on the experimental conditions) are found for unirradiated and irradiated laboratory specimens. The TiO2 layer formed on the in-situ corrosion specimens (33 nm / 5.3 years) is thinner than that of the laboratory specimens (58 nm / 191 days) indicating less aggressive conditions in the field experiments. In view of these results, the alloy Ti99.8-Pd continues to be considered as a strong candidate container material and will be further investigated.

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