The GEO Group, Inc. is a company specializing in corrections, detention and mental health treatment. The company is organized as a real estate investment trust REIT. It maintains facilities in North America, Australia, South Africa and the United Kingdom. GEO Group facilities include maximum, medium and minimum security prisons, immigration detention centers, minimum security detention centers and mental health and residential treatment facilities. Wikipedia.
Goossens D.,University of Nevada, Las Vegas |
Goossens D.,The GEO Group
Aeolian Research | Year: 2010
Wind tunnel experiments were conducted with the USGS (United States Geological Survey) dust deposition sampler to test its efficiency for dust deposition and its capacity to collect representative samples for grain size analysis. Efficiency for dust deposition was ascertained relative to a water surface, which was considered the best alternative for simulating a perfectly absorbent surface. Capacity to collect representative samples for grain size analysis was ascertained by comparing the grain size distribution of the collected dust to that of the original dust. Three versions were tested: an empty sampler, a sampler filled with glass marbles, and a sampler filled with water. Efficiencies and capacity to collect representative samples were ascertained for five wind velocities (range: 1-5ms-1) and seven grain size classes (range: 10-80μm). All samplers showed a rapid drop in collection efficiency with increasing wind speed. Efficiencies are low, in the order of 10% or less for most common wind speeds over the continents. Efficiency also drops as the particles become coarser. Adding glass marbles to the sampler increases its efficiency, protects the settled dust from resuspension, and minimizes outsplash during rainfall. The sediment collected by the sampler is finer than the original dust. The bias in the grain size is more expressed in fine particle fractions than in coarse particle fractions. The performance of the USGS sampler is rather low when compared to other dust deposition samplers, but a procedure is provided that allows calculation of the original grain size distribution and dust deposition quantities. © 2010 Elsevier B.V.
Goossens D.,University of Nevada, Las Vegas |
Goossens D.,The GEO Group |
Buck B.,University of Nevada, Las Vegas
Earth Surface Processes and Landforms | Year: 2011
Wind erosion measurements were carried out in Nellis Dunes Recreation Area, southern Nevada, USA. Gross erosion (the total mass of sediment effectively blown away from a surface), gross deposition (the total mass of sediment effectively depositing on a surface) and net erosion (the difference in sediment mass before and after an event) were measured for 1 year, on 17 different types of surfaces developed on loose dune sand, compacted sand, loose silt, compacted and/or aggregated silt, rock-covered sands and silts, mixtures of sand, silt and clay, exposed petrocalcic horizons, gravelly substrata and bedrock. Results showed that net erosion, which is the type of erosion measured in field and laboratory experiments, strongly differs from gross erosion. Activity on a surface is much higher than classic net erosion measurements suggest. Future studies on wind erosion should better acknowledge the distinction between the two types of process. Also, a grain diameter of maximum susceptibility to wind erosion ('optimum deflation diameter') near 70μm as proposed by the aeolian literature only exists for net wind erosion. No such optimum diameter was found for gross wind erosion within the particle range 0-100μm delineating the transport modes of suspension and modified saltation. In addition, desert surfaces predominantly composed of sand did not show an optimum deflation diameter (for net erosion) around 70μm. Instead, there was a preferential grain size around 15μm at which particles were most vulnerable to net emission. Desert surfaces poor in sand showed the classic value of 70μm. This suggests that interactions exist between the type of surface and the susceptibility of particles to wind erosion. This study is solely based on field data. Although results are supported by two previous wind tunnel studies, more wind tunnel experiments documenting the interactions between gross erosion and gross deposition are necessary. © 2010 John Wiley & Sons, Ltd.
Sarangi R.K.,The GEO Group
Journal of Applied Remote Sensing | Year: 2013
Abstract. Observation was made to understand the spectral behavior of aerosol from the NASA moderate resolution imaging spectroradiometer (MODIS-Aqua) sensor data. The 869 nm central wavelength band MODIS-Aqua-derived images were retrieved and interpreted. The aerosol concentration was found to be higher during December (Northeast monsoon) over the Bay of Bengal (BoB). Its characterized distinct plume with higher aerosol optical depth (AOD) ranged between 0.05 and 0.25. The coastal aerosol concentration was higher than the offshore region, with decreasing trend (AOD ? 0.05). To understand aerosol's link with ocean biological productivity in terms of phytoplankton pigment, the ocean surface chlorophyll was retrieved from 8-years monthly datasets (2002 to 2010). MODIS-Aqua-derived monthly scale aerosol and chlorophyll data were analyzed in the northern Indian Ocean (NIO) region during July 2002 to June 2010. Their interrelationship was found to be significant (r2 0.663 and 0.584) over pockets in the BoB and Arabian Sea. Land to seaward movement of wind and aerosol plays a significant role to increasing ocean productivity. This study is very important and interesting to understand the precise composition of aerosol dust like iron (Fe) and increase in sulfate ions, nitrates, etc., and their link to phytoplankton biomass and the related productivity in the Indian water and attempted for the first time in the NIO water. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE).
Sreejith K.M.,The GEO Group |
Krishna K.S.,National Institute of Oceanography of India
Journal of Geophysical Research: Solid Earth | Year: 2013
The Ninetyeast Ridge (NER), one of the longest linear volcanic features on the Earth, offers an excellent opportunity of understanding the isostatic response to the interactions of mantle plume with the migrating mid-ocean ridge. Bathymetry, geoid, and gravity (shipborne and satellite) data along 72 closely spaced transects and 17 overlapping grids on the NER are analyzed and modeled to determine the effective elastic thickness (Te) beneath the entire ridge. The results of 2-D and 3-D flexural modeling of the NER show large spatial variations in Te values ranging from 4 to 35 km, suggesting that the ridge was compensated along its length by different isostatic mechanisms. The southern (south of 22°S latitude) and northern (north of 2°N latitude) parts of the NER have Te values of >10 and >23 km, respectively, revealing that the southern part was emplaced on a lithosphere of intermediate strength possibly on flank of the Indian plate, whereas the northern part was emplaced in an intraplate setting. In contrast, in the central part of the NER (between latitudes 22°S and 2°N), highly variable Te values (4-22 km) are estimated. The scattered Te values in the central NER suggest that this part may have evolved due to the occurrence of frequent ridge jumps caused by the interaction of Kerguelen hot spot with rapid northward migration of the Wharton spreading ridge. Residual Mantle Bouguer Anomaly (RMBA) map of the NER and adjacent basins reveals that the entire length of the NER is associated with a significant negative anomaly up to 200 mGal, indicating the presence of thickened crust or less dense mantle beneath the ridge. 3-D crustal thickness map of the NER, generated by inversion of the RMBA data, shows a thick crust ranging from 15 to 19 km. The present study clearly shows that NER possesses a highly segmented isostatic pattern with the occurrence of subcrustal underplating or subsurface loading. Key Points Long aseismic ridge offers the opportunity of studying the isostasy Ridge jumps derived from isostasy Effect of rapid plate motions in isostasy ©2013. American Geophysical Union. All Rights Reserved.
Sarangi R.K.,The GEO Group
Marine Geodesy | Year: 2012
Algal bloom observed using Indian Remote Sensing Satellite IRS-P4 Ocean Color Monitor (OCM) derived chlorophyll images during December 23, 2003-January 8, 2004, off the Oman coast. High chlorophyll concentration (~20 mg m -3) patches were observed. MODIS-Aqua data of January 1, 2004, were analyzed to generate normalized water leaving radiance (nLw) images for seven visible channels: 412, 443, 488, 531, 551, 667 and 678 nm. The channels 667 and 678 nm showed interesting algal bloom features. The bloom features were detected in OCM image of January 2, 2004, using Subramanian's Trichodesmium detection Protocol. MODIS-Aqua retrieved Sea Surface Temperature (SST) around the bloom patches was observed to be >240°C. The OCM chlorophyll mean observed to be very high (>10.0 mg m -3) in two bloom pockets. Quickscat scatterometer derived wind speed was found to be optimum in the range of 3-5 m/sec. © 2012 Copyright Taylor and Francis Group, LLC.